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pandas-bug-163 | """
Provide a generic structure to support window functions,
similar to how we have a Groupby object.
"""
from collections import defaultdict
from datetime import timedelta
from textwrap import dedent
from typing import Callable, List, Optional, Set, Union
import warnings
import numpy as np
import pandas._libs.window as libwindow
from pandas.compat._optional import import_optional_dependency
from pandas.compat.numpy import function as nv
from pandas.util._decorators import Appender, Substitution, cache_readonly
from pandas.core.dtypes.common import (
ensure_float64,
is_bool,
is_float_dtype,
is_integer,
is_integer_dtype,
is_list_like,
is_scalar,
is_timedelta64_dtype,
needs_i8_conversion,
)
from pandas.core.dtypes.generic import (
ABCDataFrame,
ABCDateOffset,
ABCDatetimeIndex,
ABCPeriodIndex,
ABCSeries,
ABCTimedeltaIndex,
)
from pandas._typing import Axis, FrameOrSeries, Scalar
from pandas.core.base import DataError, PandasObject, SelectionMixin
import pandas.core.common as com
from pandas.core.generic import _shared_docs
from pandas.core.groupby.base import GroupByMixin
from pandas.core.index import Index, MultiIndex, ensure_index
_shared_docs = dict(**_shared_docs)
_doc_template = """
Returns
-------
Series or DataFrame
Return type is determined by the caller.
See Also
--------
Series.%(name)s : Series %(name)s.
DataFrame.%(name)s : DataFrame %(name)s.
"""
class _Window(PandasObject, SelectionMixin):
_attributes = [
"window",
"min_periods",
"center",
"win_type",
"axis",
"on",
"closed",
] # type: List[str]
exclusions = set() # type: Set[str]
def __init__(
self,
obj,
window=None,
min_periods: Optional[int] = None,
center: Optional[bool] = False,
win_type: Optional[str] = None,
axis: Axis = 0,
on: Optional[str] = None,
closed: Optional[str] = None,
**kwargs
):
self.__dict__.update(kwargs)
self.obj = obj
self.on = on
self.closed = closed
self.window = window
self.min_periods = min_periods
self.center = center
self.win_type = win_type
self.win_freq = None
self.axis = obj._get_axis_number(axis) if axis is not None else None
self.validate()
@property
def _constructor(self):
return Window
@property
def is_datetimelike(self) -> Optional[bool]:
return None
@property
def _on(self):
return None
@property
def is_freq_type(self) -> bool:
return self.win_type == "freq"
def validate(self):
if self.center is not None and not is_bool(self.center):
raise ValueError("center must be a boolean")
if self.min_periods is not None and not is_integer(self.min_periods):
raise ValueError("min_periods must be an integer")
if self.closed is not None and self.closed not in [
"right",
"both",
"left",
"neither",
]:
raise ValueError("closed must be 'right', 'left', 'both' or 'neither'")
def _create_blocks(self):
"""
Split data into blocks & return conformed data.
"""
obj = self._selected_obj
# filter out the on from the object
if self.on is not None:
if obj.ndim == 2:
obj = obj.reindex(columns=obj.columns.difference([self.on]), copy=False)
blocks = obj._to_dict_of_blocks(copy=False).values()
return blocks, obj
def _gotitem(self, key, ndim, subset=None):
"""
Sub-classes to define. Return a sliced object.
Parameters
----------
key : str / list of selections
ndim : 1,2
requested ndim of result
subset : object, default None
subset to act on
"""
# create a new object to prevent aliasing
if subset is None:
subset = self.obj
self = self._shallow_copy(subset)
self._reset_cache()
if subset.ndim == 2:
if is_scalar(key) and key in subset or is_list_like(key):
self._selection = key
return self
def __getattr__(self, attr):
if attr in self._internal_names_set:
return object.__getattribute__(self, attr)
if attr in self.obj:
return self[attr]
raise AttributeError(
"%r object has no attribute %r" % (type(self).__name__, attr)
)
def _dir_additions(self):
return self.obj._dir_additions()
def _get_window(self, other=None, **kwargs) -> int:
"""
Returns window length
Parameters
----------
other:
ignored, exists for compatibility
Returns
-------
window : int
"""
return self.window
@property
def _window_type(self) -> str:
return self.__class__.__name__
def __repr__(self) -> str:
"""
Provide a nice str repr of our rolling object.
"""
attrs = (
"{k}={v}".format(k=k, v=getattr(self, k))
for k in self._attributes
if getattr(self, k, None) is not None
)
return "{klass} [{attrs}]".format(
klass=self._window_type, attrs=",".join(attrs)
)
def __iter__(self):
url = "https://github.com/pandas-dev/pandas/issues/11704"
raise NotImplementedError("See issue #11704 {url}".format(url=url))
def _get_index(self) -> Optional[np.ndarray]:
"""
Return integer representations as an ndarray if index is frequency.
Returns
-------
None or ndarray
"""
if self.is_freq_type:
return self._on.asi8
return None
def _prep_values(self, values: Optional[np.ndarray] = None) -> np.ndarray:
"""Convert input to numpy arrays for Cython routines"""
if values is None:
values = getattr(self._selected_obj, "values", self._selected_obj)
# GH #12373 : rolling functions error on float32 data
# make sure the data is coerced to float64
if is_float_dtype(values.dtype):
values = ensure_float64(values)
elif is_integer_dtype(values.dtype):
values = ensure_float64(values)
elif needs_i8_conversion(values.dtype):
raise NotImplementedError(
"ops for {action} for this "
"dtype {dtype} are not "
"implemented".format(action=self._window_type, dtype=values.dtype)
)
else:
try:
values = ensure_float64(values)
except (ValueError, TypeError):
raise TypeError("cannot handle this type -> {0}".format(values.dtype))
# Always convert inf to nan
values[np.isinf(values)] = np.NaN
return values
def _wrap_result(self, result, block=None, obj=None):
"""
Wrap a single result.
"""
if obj is None:
obj = self._selected_obj
index = obj.index
if isinstance(result, np.ndarray):
# coerce if necessary
if block is not None:
if is_timedelta64_dtype(block.values.dtype):
# TODO: do we know what result.dtype is at this point?
# i.e. can we just do an astype?
from pandas import to_timedelta
result = to_timedelta(result.ravel(), unit="ns").values.reshape(
result.shape
)
if result.ndim == 1:
from pandas import Series
return Series(result, index, name=obj.name)
return type(obj)(result, index=index, columns=block.columns)
return result
def _wrap_results(self, results, blocks, obj, exclude=None) -> FrameOrSeries:
"""
Wrap the results.
Parameters
----------
results : list of ndarrays
blocks : list of blocks
obj : conformed data (may be resampled)
exclude: list of columns to exclude, default to None
"""
from pandas import Series, concat
final = []
for result, block in zip(results, blocks):
result = self._wrap_result(result, block=block, obj=obj)
if result.ndim == 1:
return result
final.append(result)
# if we have an 'on' column
# we want to put it back into the results
# in the same location
columns = self._selected_obj.columns
if self.on is not None and not self._on.equals(obj.index):
name = self._on.name
final.append(Series(self._on, index=obj.index, name=name))
if self._selection is not None:
selection = ensure_index(self._selection)
# need to reorder to include original location of
# the on column (if its not already there)
if name not in selection:
columns = self.obj.columns
indexer = columns.get_indexer(selection.tolist() + [name])
columns = columns.take(sorted(indexer))
# exclude nuisance columns so that they are not reindexed
if exclude is not None and exclude:
columns = [c for c in columns if c not in exclude]
if not columns:
raise DataError("No numeric types to aggregate")
if not len(final):
return obj.astype("float64")
return concat(final, axis=1).reindex(columns=columns, copy=False)
def _center_window(self, result, window) -> np.ndarray:
"""
Center the result in the window.
"""
if self.axis > result.ndim - 1:
raise ValueError("Requested axis is larger then no. of argument dimensions")
offset = _offset(window, True)
if offset > 0:
if isinstance(result, (ABCSeries, ABCDataFrame)):
result = result.slice_shift(-offset, axis=self.axis)
else:
lead_indexer = [slice(None)] * result.ndim
lead_indexer[self.axis] = slice(offset, None)
result = np.copy(result[tuple(lead_indexer)])
return result
def _get_roll_func(
self, cfunc: Callable, check_minp: Callable, index: np.ndarray, **kwargs
) -> Callable:
"""
Wrap rolling function to check values passed.
Parameters
----------
cfunc : callable
Cython function used to calculate rolling statistics
check_minp : callable
function to check minimum period parameter
index : ndarray
used for variable window
Returns
-------
func : callable
"""
def func(arg, window, min_periods=None, closed=None):
minp = check_minp(min_periods, window)
return cfunc(arg, window, minp, index, closed, **kwargs)
return func
def _apply(
self,
func: Union[str, Callable],
name: Optional[str] = None,
window: Optional[Union[int, str]] = None,
center: Optional[bool] = None,
check_minp: Optional[Callable] = None,
**kwargs
):
"""
Rolling statistical measure using supplied function.
Designed to be used with passed-in Cython array-based functions.
Parameters
----------
func : str/callable to apply
name : str, optional
name of this function
window : int/str, default to _get_window()
window length or offset
center : bool, default to self.center
check_minp : function, default to _use_window
**kwargs
additional arguments for rolling function and window function
Returns
-------
y : type of input
"""
if center is None:
center = self.center
if check_minp is None:
check_minp = _use_window
if window is None:
window = self._get_window(**kwargs)
blocks, obj = self._create_blocks()
block_list = list(blocks)
index_as_array = self._get_index()
results = []
exclude = [] # type: List[Scalar]
for i, b in enumerate(blocks):
try:
values = self._prep_values(b.values)
except (TypeError, NotImplementedError):
if isinstance(obj, ABCDataFrame):
exclude.extend(b.columns)
del block_list[i]
continue
else:
raise DataError("No numeric types to aggregate")
if values.size == 0:
results.append(values.copy())
continue
# if we have a string function name, wrap it
if isinstance(func, str):
cfunc = getattr(libwindow, func, None)
if cfunc is None:
raise ValueError(
"we do not support this function "
"in libwindow.{func}".format(func=func)
)
func = self._get_roll_func(cfunc, check_minp, index_as_array, **kwargs)
# calculation function
if center:
offset = _offset(window, center)
additional_nans = np.array([np.NaN] * offset)
def calc(x):
return func(
np.concatenate((x, additional_nans)),
window,
min_periods=self.min_periods,
closed=self.closed,
)
else:
def calc(x):
return func(
x, window, min_periods=self.min_periods, closed=self.closed
)
with np.errstate(all="ignore"):
if values.ndim > 1:
result = np.apply_along_axis(calc, self.axis, values)
else:
result = calc(values)
result = np.asarray(result)
if center:
result = self._center_window(result, window)
results.append(result)
return self._wrap_results(results, block_list, obj, exclude)
def aggregate(self, func, *args, **kwargs):
result, how = self._aggregate(func, *args, **kwargs)
if result is None:
return self.apply(func, raw=False, args=args, kwargs=kwargs)
return result
agg = aggregate
_shared_docs["sum"] = dedent(
"""
Calculate %(name)s sum of given DataFrame or Series.
Parameters
----------
*args, **kwargs
For compatibility with other %(name)s methods. Has no effect
on the computed value.
Returns
-------
Series or DataFrame
Same type as the input, with the same index, containing the
%(name)s sum.
See Also
--------
Series.sum : Reducing sum for Series.
DataFrame.sum : Reducing sum for DataFrame.
Examples
--------
>>> s = pd.Series([1, 2, 3, 4, 5])
>>> s
0 1
1 2
2 3
3 4
4 5
dtype: int64
>>> s.rolling(3).sum()
0 NaN
1 NaN
2 6.0
3 9.0
4 12.0
dtype: float64
>>> s.expanding(3).sum()
0 NaN
1 NaN
2 6.0
3 10.0
4 15.0
dtype: float64
>>> s.rolling(3, center=True).sum()
0 NaN
1 6.0
2 9.0
3 12.0
4 NaN
dtype: float64
For DataFrame, each %(name)s sum is computed column-wise.
>>> df = pd.DataFrame({"A": s, "B": s ** 2})
>>> df
A B
0 1 1
1 2 4
2 3 9
3 4 16
4 5 25
>>> df.rolling(3).sum()
A B
0 NaN NaN
1 NaN NaN
2 6.0 14.0
3 9.0 29.0
4 12.0 50.0
"""
)
_shared_docs["mean"] = dedent(
"""
Calculate the %(name)s mean of the values.
Parameters
----------
*args
Under Review.
**kwargs
Under Review.
Returns
-------
Series or DataFrame
Returned object type is determined by the caller of the %(name)s
calculation.
See Also
--------
Series.%(name)s : Calling object with Series data.
DataFrame.%(name)s : Calling object with DataFrames.
Series.mean : Equivalent method for Series.
DataFrame.mean : Equivalent method for DataFrame.
Examples
--------
The below examples will show rolling mean calculations with window sizes of
two and three, respectively.
>>> s = pd.Series([1, 2, 3, 4])
>>> s.rolling(2).mean()
0 NaN
1 1.5
2 2.5
3 3.5
dtype: float64
>>> s.rolling(3).mean()
0 NaN
1 NaN
2 2.0
3 3.0
dtype: float64
"""
)
class Window(_Window):
"""
Provide rolling window calculations.
Parameters
----------
window : int, or offset
Size of the moving window. This is the number of observations used for
calculating the statistic. Each window will be a fixed size.
If its an offset then this will be the time period of each window. Each
window will be a variable sized based on the observations included in
the time-period. This is only valid for datetimelike indexes.
min_periods : int, default None
Minimum number of observations in window required to have a value
(otherwise result is NA). For a window that is specified by an offset,
`min_periods` will default to 1. Otherwise, `min_periods` will default
to the size of the window.
center : bool, default False
Set the labels at the center of the window.
win_type : str, default None
Provide a window type. If ``None``, all points are evenly weighted.
See the notes below for further information.
on : str, optional
For a DataFrame, a datetime-like column on which to calculate the rolling
window, rather than the DataFrame's index. Provided integer column is
ignored and excluded from result since an integer index is not used to
calculate the rolling window.
axis : int or str, default 0
closed : str, default None
Make the interval closed on the 'right', 'left', 'both' or
'neither' endpoints.
For offset-based windows, it defaults to 'right'.
For fixed windows, defaults to 'both'. Remaining cases not implemented
for fixed windows.
.. versionadded:: 0.20.0
Returns
-------
a Window or Rolling sub-classed for the particular operation
See Also
--------
expanding : Provides expanding transformations.
ewm : Provides exponential weighted functions.
Notes
-----
By default, the result is set to the right edge of the window. This can be
changed to the center of the window by setting ``center=True``.
To learn more about the offsets & frequency strings, please see `this link
<http://pandas.pydata.org/pandas-docs/stable/user_guide/timeseries.html#offset-aliases>`__.
The recognized win_types are:
* ``boxcar``
* ``triang``
* ``blackman``
* ``hamming``
* ``bartlett``
* ``parzen``
* ``bohman``
* ``blackmanharris``
* ``nuttall``
* ``barthann``
* ``kaiser`` (needs beta)
* ``gaussian`` (needs std)
* ``general_gaussian`` (needs power, width)
* ``slepian`` (needs width)
* ``exponential`` (needs tau), center is set to None.
If ``win_type=None`` all points are evenly weighted. To learn more about
different window types see `scipy.signal window functions
<https://docs.scipy.org/doc/scipy/reference/signal.html#window-functions>`__.
Examples
--------
>>> df = pd.DataFrame({'B': [0, 1, 2, np.nan, 4]})
>>> df
B
0 0.0
1 1.0
2 2.0
3 NaN
4 4.0
Rolling sum with a window length of 2, using the 'triang'
window type.
>>> df.rolling(2, win_type='triang').sum()
B
0 NaN
1 0.5
2 1.5
3 NaN
4 NaN
Rolling sum with a window length of 2, min_periods defaults
to the window length.
>>> df.rolling(2).sum()
B
0 NaN
1 1.0
2 3.0
3 NaN
4 NaN
Same as above, but explicitly set the min_periods
>>> df.rolling(2, min_periods=1).sum()
B
0 0.0
1 1.0
2 3.0
3 2.0
4 4.0
A ragged (meaning not-a-regular frequency), time-indexed DataFrame
>>> df = pd.DataFrame({'B': [0, 1, 2, np.nan, 4]},
... index = [pd.Timestamp('20130101 09:00:00'),
... pd.Timestamp('20130101 09:00:02'),
... pd.Timestamp('20130101 09:00:03'),
... pd.Timestamp('20130101 09:00:05'),
... pd.Timestamp('20130101 09:00:06')])
>>> df
B
2013-01-01 09:00:00 0.0
2013-01-01 09:00:02 1.0
2013-01-01 09:00:03 2.0
2013-01-01 09:00:05 NaN
2013-01-01 09:00:06 4.0
Contrasting to an integer rolling window, this will roll a variable
length window corresponding to the time period.
The default for min_periods is 1.
>>> df.rolling('2s').sum()
B
2013-01-01 09:00:00 0.0
2013-01-01 09:00:02 1.0
2013-01-01 09:00:03 3.0
2013-01-01 09:00:05 NaN
2013-01-01 09:00:06 4.0
"""
def validate(self):
super().validate()
window = self.window
if isinstance(window, (list, tuple, np.ndarray)):
pass
elif is_integer(window):
if window <= 0:
raise ValueError("window must be > 0 ")
import_optional_dependency(
"scipy", extra="Scipy is required to generate window weight."
)
import scipy.signal as sig
if not isinstance(self.win_type, str):
raise ValueError("Invalid win_type {0}".format(self.win_type))
if getattr(sig, self.win_type, None) is None:
raise ValueError("Invalid win_type {0}".format(self.win_type))
else:
raise ValueError("Invalid window {0}".format(window))
def _get_window(self, other=None, **kwargs) -> np.ndarray:
"""
Provide validation for the window type, return the window
which has already been validated.
Parameters
----------
other:
ignored, exists for compatibility
Returns
-------
window : ndarray
the window, weights
"""
window = self.window
if isinstance(window, (list, tuple, np.ndarray)):
return com.asarray_tuplesafe(window).astype(float)
elif is_integer(window):
import scipy.signal as sig
# the below may pop from kwargs
def _validate_win_type(win_type, kwargs):
arg_map = {
"kaiser": ["beta"],
"gaussian": ["std"],
"general_gaussian": ["power", "width"],
"slepian": ["width"],
"exponential": ["tau"],
}
if win_type in arg_map:
win_args = _pop_args(win_type, arg_map[win_type], kwargs)
if win_type == "exponential":
# exponential window requires the first arg (center)
# to be set to None (necessary for symmetric window)
win_args.insert(0, None)
return tuple([win_type] + win_args)
return win_type
def _pop_args(win_type, arg_names, kwargs):
msg = "%s window requires %%s" % win_type
all_args = []
for n in arg_names:
if n not in kwargs:
raise ValueError(msg % n)
all_args.append(kwargs.pop(n))
return all_args
win_type = _validate_win_type(self.win_type, kwargs)
# GH #15662. `False` makes symmetric window, rather than periodic.
return sig.get_window(win_type, window, False).astype(float)
def _get_roll_func(
self, cfunc: Callable, check_minp: Callable, index: np.ndarray, **kwargs
) -> Callable:
def func(arg, window, min_periods=None, closed=None):
minp = check_minp(min_periods, len(window))
return cfunc(arg, window, minp)
return func
_agg_see_also_doc = dedent(
"""
See Also
--------
pandas.DataFrame.rolling.aggregate
pandas.DataFrame.aggregate
"""
)
_agg_examples_doc = dedent(
"""
Examples
--------
>>> df = pd.DataFrame(np.random.randn(10, 3), columns=['A', 'B', 'C'])
>>> df
A B C
0 -2.385977 -0.102758 0.438822
1 -1.004295 0.905829 -0.954544
2 0.735167 -0.165272 -1.619346
3 -0.702657 -1.340923 -0.706334
4 -0.246845 0.211596 -0.901819
5 2.463718 3.157577 -1.380906
6 -1.142255 2.340594 -0.039875
7 1.396598 -1.647453 1.677227
8 -0.543425 1.761277 -0.220481
9 -0.640505 0.289374 -1.550670
>>> df.rolling(3, win_type='boxcar').agg('mean')
A B C
0 NaN NaN NaN
1 NaN NaN NaN
2 -0.885035 0.212600 -0.711689
3 -0.323928 -0.200122 -1.093408
4 -0.071445 -0.431533 -1.075833
5 0.504739 0.676083 -0.996353
6 0.358206 1.903256 -0.774200
7 0.906020 1.283573 0.085482
8 -0.096361 0.818139 0.472290
9 0.070889 0.134399 -0.031308
"""
)
@Substitution(
see_also=_agg_see_also_doc,
examples=_agg_examples_doc,
versionadded="",
klass="Series/DataFrame",
axis="",
)
@Appender(_shared_docs["aggregate"])
def aggregate(self, arg, *args, **kwargs):
result, how = self._aggregate(arg, *args, **kwargs)
if result is None:
# these must apply directly
result = arg(self)
return result
agg = aggregate
@Substitution(name="window")
@Appender(_shared_docs["sum"])
def sum(self, *args, **kwargs):
nv.validate_window_func("sum", args, kwargs)
return self._apply("roll_weighted_sum", **kwargs)
@Substitution(name="window")
@Appender(_shared_docs["mean"])
def mean(self, *args, **kwargs):
nv.validate_window_func("mean", args, kwargs)
return self._apply("roll_weighted_mean", **kwargs)
class _GroupByMixin(GroupByMixin):
"""
Provide the groupby facilities.
"""
def __init__(self, obj, *args, **kwargs):
parent = kwargs.pop("parent", None) # noqa
groupby = kwargs.pop("groupby", None)
if groupby is None:
groupby, obj = obj, obj.obj
self._groupby = groupby
self._groupby.mutated = True
self._groupby.grouper.mutated = True
super().__init__(obj, *args, **kwargs)
count = GroupByMixin._dispatch("count")
corr = GroupByMixin._dispatch("corr", other=None, pairwise=None)
cov = GroupByMixin._dispatch("cov", other=None, pairwise=None)
def _apply(
self, func, name=None, window=None, center=None, check_minp=None, **kwargs
):
"""
Dispatch to apply; we are stripping all of the _apply kwargs and
performing the original function call on the grouped object.
"""
def f(x, name=name, *args):
x = self._shallow_copy(x)
if isinstance(name, str):
return getattr(x, name)(*args, **kwargs)
return x.apply(name, *args, **kwargs)
return self._groupby.apply(f)
class _Rolling(_Window):
@property
def _constructor(self):
return Rolling
class _Rolling_and_Expanding(_Rolling):
_shared_docs["count"] = dedent(
r"""
The %(name)s count of any non-NaN observations inside the window.
Returns
-------
Series or DataFrame
Returned object type is determined by the caller of the %(name)s
calculation.
See Also
--------
Series.%(name)s : Calling object with Series data.
DataFrame.%(name)s : Calling object with DataFrames.
DataFrame.count : Count of the full DataFrame.
Examples
--------
>>> s = pd.Series([2, 3, np.nan, 10])
>>> s.rolling(2).count()
0 1.0
1 2.0
2 1.0
3 1.0
dtype: float64
>>> s.rolling(3).count()
0 1.0
1 2.0
2 2.0
3 2.0
dtype: float64
>>> s.rolling(4).count()
0 1.0
1 2.0
2 2.0
3 3.0
dtype: float64
"""
)
def count(self):
blocks, obj = self._create_blocks()
# Validate the index
self._get_index()
window = self._get_window()
window = min(window, len(obj)) if not self.center else window
results = []
for b in blocks:
result = b.notna().astype(int)
result = self._constructor(
result,
window=window,
min_periods=0,
center=self.center,
axis=self.axis,
closed=self.closed,
).sum()
results.append(result)
return self._wrap_results(results, blocks, obj)
_shared_docs["apply"] = dedent(
r"""
The %(name)s function's apply function.
Parameters
----------
func : function
Must produce a single value from an ndarray input if ``raw=True``
or a single value from a Series if ``raw=False``.
raw : bool, default None
* ``False`` : passes each row or column as a Series to the
function.
* ``True`` or ``None`` : the passed function will receive ndarray
objects instead.
If you are just applying a NumPy reduction function this will
achieve much better performance.
The `raw` parameter is required and will show a FutureWarning if
not passed. In the future `raw` will default to False.
.. versionadded:: 0.23.0
*args, **kwargs
Arguments and keyword arguments to be passed into func.
Returns
-------
Series or DataFrame
Return type is determined by the caller.
See Also
--------
Series.%(name)s : Series %(name)s.
DataFrame.%(name)s : DataFrame %(name)s.
"""
)
def apply(self, func, raw=None, args=(), kwargs={}):
from pandas import Series
kwargs.pop("_level", None)
window = self._get_window()
offset = _offset(window, self.center)
index_as_array = self._get_index()
# TODO: default is for backward compat
# change to False in the future
if raw is None:
warnings.warn(
"Currently, 'apply' passes the values as ndarrays to the "
"applied function. In the future, this will change to passing "
"it as Series objects. You need to specify 'raw=True' to keep "
"the current behaviour, and you can pass 'raw=False' to "
"silence this warning",
FutureWarning,
stacklevel=3,
)
raw = True
def f(arg, window, min_periods, closed):
minp = _use_window(min_periods, window)
if not raw:
arg = Series(arg, index=self.obj.index)
return libwindow.roll_generic(
arg,
window,
minp,
index_as_array,
closed,
offset,
func,
raw,
args,
kwargs,
)
return self._apply(f, func, args=args, kwargs=kwargs, center=False, raw=raw)
def sum(self, *args, **kwargs):
nv.validate_window_func("sum", args, kwargs)
return self._apply("roll_sum", "sum", **kwargs)
_shared_docs["max"] = dedent(
"""
Calculate the %(name)s maximum.
Parameters
----------
*args, **kwargs
Arguments and keyword arguments to be passed into func.
"""
)
def max(self, *args, **kwargs):
nv.validate_window_func("max", args, kwargs)
return self._apply("roll_max", "max", **kwargs)
_shared_docs["min"] = dedent(
"""
Calculate the %(name)s minimum.
Parameters
----------
**kwargs
Under Review.
Returns
-------
Series or DataFrame
Returned object type is determined by the caller of the %(name)s
calculation.
See Also
--------
Series.%(name)s : Calling object with a Series.
DataFrame.%(name)s : Calling object with a DataFrame.
Series.min : Similar method for Series.
DataFrame.min : Similar method for DataFrame.
Examples
--------
Performing a rolling minimum with a window size of 3.
>>> s = pd.Series([4, 3, 5, 2, 6])
>>> s.rolling(3).min()
0 NaN
1 NaN
2 3.0
3 2.0
4 2.0
dtype: float64
"""
)
def min(self, *args, **kwargs):
nv.validate_window_func("min", args, kwargs)
return self._apply("roll_min", "min", **kwargs)
def mean(self, *args, **kwargs):
nv.validate_window_func("mean", args, kwargs)
return self._apply("roll_mean", "mean", **kwargs)
_shared_docs["median"] = dedent(
"""
Calculate the %(name)s median.
Parameters
----------
**kwargs
For compatibility with other %(name)s methods. Has no effect
on the computed median.
Returns
-------
Series or DataFrame
Returned type is the same as the original object.
See Also
--------
Series.%(name)s : Calling object with Series data.
DataFrame.%(name)s : Calling object with DataFrames.
Series.median : Equivalent method for Series.
DataFrame.median : Equivalent method for DataFrame.
Examples
--------
Compute the rolling median of a series with a window size of 3.
>>> s = pd.Series([0, 1, 2, 3, 4])
>>> s.rolling(3).median()
0 NaN
1 NaN
2 1.0
3 2.0
4 3.0
dtype: float64
"""
)
def median(self, **kwargs):
return self._apply("roll_median_c", "median", **kwargs)
_shared_docs["std"] = dedent(
"""
Calculate %(name)s standard deviation.
Normalized by N-1 by default. This can be changed using the `ddof`
argument.
Parameters
----------
ddof : int, default 1
Delta Degrees of Freedom. The divisor used in calculations
is ``N - ddof``, where ``N`` represents the number of elements.
*args, **kwargs
For NumPy compatibility. No additional arguments are used.
Returns
-------
Series or DataFrame
Returns the same object type as the caller of the %(name)s calculation.
See Also
--------
Series.%(name)s : Calling object with Series data.
DataFrame.%(name)s : Calling object with DataFrames.
Series.std : Equivalent method for Series.
DataFrame.std : Equivalent method for DataFrame.
numpy.std : Equivalent method for Numpy array.
Notes
-----
The default `ddof` of 1 used in Series.std is different than the default
`ddof` of 0 in numpy.std.
A minimum of one period is required for the rolling calculation.
Examples
--------
>>> s = pd.Series([5, 5, 6, 7, 5, 5, 5])
>>> s.rolling(3).std()
0 NaN
1 NaN
2 0.577350
3 1.000000
4 1.000000
5 1.154701
6 0.000000
dtype: float64
>>> s.expanding(3).std()
0 NaN
1 NaN
2 0.577350
3 0.957427
4 0.894427
5 0.836660
6 0.786796
dtype: float64
"""
)
def std(self, ddof=1, *args, **kwargs):
nv.validate_window_func("std", args, kwargs)
window = self._get_window()
index_as_array = self._get_index()
def f(arg, *args, **kwargs):
minp = _require_min_periods(1)(self.min_periods, window)
return _zsqrt(
libwindow.roll_var(arg, window, minp, index_as_array, self.closed, ddof)
)
return self._apply(
f, "std", check_minp=_require_min_periods(1), ddof=ddof, **kwargs
)
_shared_docs["var"] = dedent(
"""
Calculate unbiased %(name)s variance.
Normalized by N-1 by default. This can be changed using the `ddof`
argument.
Parameters
----------
ddof : int, default 1
Delta Degrees of Freedom. The divisor used in calculations
is ``N - ddof``, where ``N`` represents the number of elements.
*args, **kwargs
For NumPy compatibility. No additional arguments are used.
Returns
-------
Series or DataFrame
Returns the same object type as the caller of the %(name)s calculation.
See Also
--------
Series.%(name)s : Calling object with Series data.
DataFrame.%(name)s : Calling object with DataFrames.
Series.var : Equivalent method for Series.
DataFrame.var : Equivalent method for DataFrame.
numpy.var : Equivalent method for Numpy array.
Notes
-----
The default `ddof` of 1 used in :meth:`Series.var` is different than the
default `ddof` of 0 in :func:`numpy.var`.
A minimum of 1 period is required for the rolling calculation.
Examples
--------
>>> s = pd.Series([5, 5, 6, 7, 5, 5, 5])
>>> s.rolling(3).var()
0 NaN
1 NaN
2 0.333333
3 1.000000
4 1.000000
5 1.333333
6 0.000000
dtype: float64
>>> s.expanding(3).var()
0 NaN
1 NaN
2 0.333333
3 0.916667
4 0.800000
5 0.700000
6 0.619048
dtype: float64
"""
)
def var(self, ddof=1, *args, **kwargs):
nv.validate_window_func("var", args, kwargs)
return self._apply(
"roll_var", "var", check_minp=_require_min_periods(1), ddof=ddof, **kwargs
)
_shared_docs[
"skew"
] = """
Unbiased %(name)s skewness.
Parameters
----------
**kwargs
Keyword arguments to be passed into func.
"""
def skew(self, **kwargs):
return self._apply(
"roll_skew", "skew", check_minp=_require_min_periods(3), **kwargs
)
_shared_docs["kurt"] = dedent(
"""
Calculate unbiased %(name)s kurtosis.
This function uses Fisher's definition of kurtosis without bias.
Parameters
----------
**kwargs
Under Review.
Returns
-------
Series or DataFrame
Returned object type is determined by the caller of the %(name)s
calculation.
See Also
--------
Series.%(name)s : Calling object with Series data.
DataFrame.%(name)s : Calling object with DataFrames.
Series.kurt : Equivalent method for Series.
DataFrame.kurt : Equivalent method for DataFrame.
scipy.stats.skew : Third moment of a probability density.
scipy.stats.kurtosis : Reference SciPy method.
Notes
-----
A minimum of 4 periods is required for the %(name)s calculation.
"""
)
def kurt(self, **kwargs):
return self._apply(
"roll_kurt", "kurt", check_minp=_require_min_periods(4), **kwargs
)
_shared_docs["quantile"] = dedent(
"""
Calculate the %(name)s quantile.
Parameters
----------
quantile : float
Quantile to compute. 0 <= quantile <= 1.
interpolation : {'linear', 'lower', 'higher', 'midpoint', 'nearest'}
.. versionadded:: 0.23.0
This optional parameter specifies the interpolation method to use,
when the desired quantile lies between two data points `i` and `j`:
* linear: `i + (j - i) * fraction`, where `fraction` is the
fractional part of the index surrounded by `i` and `j`.
* lower: `i`.
* higher: `j`.
* nearest: `i` or `j` whichever is nearest.
* midpoint: (`i` + `j`) / 2.
**kwargs:
For compatibility with other %(name)s methods. Has no effect on
the result.
Returns
-------
Series or DataFrame
Returned object type is determined by the caller of the %(name)s
calculation.
See Also
--------
Series.quantile : Computes value at the given quantile over all data
in Series.
DataFrame.quantile : Computes values at the given quantile over
requested axis in DataFrame.
Examples
--------
>>> s = pd.Series([1, 2, 3, 4])
>>> s.rolling(2).quantile(.4, interpolation='lower')
0 NaN
1 1.0
2 2.0
3 3.0
dtype: float64
>>> s.rolling(2).quantile(.4, interpolation='midpoint')
0 NaN
1 1.5
2 2.5
3 3.5
dtype: float64
"""
)
def quantile(self, quantile, interpolation="linear", **kwargs):
window = self._get_window()
index_as_array = self._get_index()
def f(arg, *args, **kwargs):
minp = _use_window(self.min_periods, window)
if quantile == 1.0:
return libwindow.roll_max(
arg, window, minp, index_as_array, self.closed
)
elif quantile == 0.0:
return libwindow.roll_min(
arg, window, minp, index_as_array, self.closed
)
else:
return libwindow.roll_quantile(
arg,
window,
minp,
index_as_array,
self.closed,
quantile,
interpolation,
)
return self._apply(f, "quantile", quantile=quantile, **kwargs)
_shared_docs[
"cov"
] = """
Calculate the %(name)s sample covariance.
Parameters
----------
other : Series, DataFrame, or ndarray, optional
If not supplied then will default to self and produce pairwise
output.
pairwise : bool, default None
If False then only matching columns between self and other will be
used and the output will be a DataFrame.
If True then all pairwise combinations will be calculated and the
output will be a MultiIndexed DataFrame in the case of DataFrame
inputs. In the case of missing elements, only complete pairwise
observations will be used.
ddof : int, default 1
Delta Degrees of Freedom. The divisor used in calculations
is ``N - ddof``, where ``N`` represents the number of elements.
**kwargs
Keyword arguments to be passed into func.
"""
def cov(self, other=None, pairwise=None, ddof=1, **kwargs):
if other is None:
other = self._selected_obj
# only default unset
pairwise = True if pairwise is None else pairwise
other = self._shallow_copy(other)
# GH 16058: offset window
if self.is_freq_type:
window = self.win_freq
else:
window = self._get_window(other)
def _get_cov(X, Y):
# GH #12373 : rolling functions error on float32 data
# to avoid potential overflow, cast the data to float64
X = X.astype("float64")
Y = Y.astype("float64")
mean = lambda x: x.rolling(
window, self.min_periods, center=self.center
).mean(**kwargs)
count = (X + Y).rolling(window=window, center=self.center).count(**kwargs)
bias_adj = count / (count - ddof)
return (mean(X * Y) - mean(X) * mean(Y)) * bias_adj
return _flex_binary_moment(
self._selected_obj, other._selected_obj, _get_cov, pairwise=bool(pairwise)
)
_shared_docs["corr"] = dedent(
"""
Calculate %(name)s correlation.
Parameters
----------
other : Series, DataFrame, or ndarray, optional
If not supplied then will default to self.
pairwise : bool, default None
Calculate pairwise combinations of columns within a
DataFrame. If `other` is not specified, defaults to `True`,
otherwise defaults to `False`.
Not relevant for :class:`~pandas.Series`.
**kwargs
Unused.
Returns
-------
Series or DataFrame
Returned object type is determined by the caller of the
%(name)s calculation.
See Also
--------
Series.%(name)s : Calling object with Series data.
DataFrame.%(name)s : Calling object with DataFrames.
Series.corr : Equivalent method for Series.
DataFrame.corr : Equivalent method for DataFrame.
%(name)s.cov : Similar method to calculate covariance.
numpy.corrcoef : NumPy Pearson's correlation calculation.
Notes
-----
This function uses Pearson's definition of correlation
(https://en.wikipedia.org/wiki/Pearson_correlation_coefficient).
When `other` is not specified, the output will be self correlation (e.g.
all 1's), except for :class:`~pandas.DataFrame` inputs with `pairwise`
set to `True`.
Function will return ``NaN`` for correlations of equal valued sequences;
this is the result of a 0/0 division error.
When `pairwise` is set to `False`, only matching columns between `self` and
`other` will be used.
When `pairwise` is set to `True`, the output will be a MultiIndex DataFrame
with the original index on the first level, and the `other` DataFrame
columns on the second level.
In the case of missing elements, only complete pairwise observations
will be used.
Examples
--------
The below example shows a rolling calculation with a window size of
four matching the equivalent function call using :meth:`numpy.corrcoef`.
>>> v1 = [3, 3, 3, 5, 8]
>>> v2 = [3, 4, 4, 4, 8]
>>> fmt = "{0:.6f}" # limit the printed precision to 6 digits
>>> # numpy returns a 2X2 array, the correlation coefficient
>>> # is the number at entry [0][1]
>>> print(fmt.format(np.corrcoef(v1[:-1], v2[:-1])[0][1]))
0.333333
>>> print(fmt.format(np.corrcoef(v1[1:], v2[1:])[0][1]))
0.916949
>>> s1 = pd.Series(v1)
>>> s2 = pd.Series(v2)
>>> s1.rolling(4).corr(s2)
0 NaN
1 NaN
2 NaN
3 0.333333
4 0.916949
dtype: float64
The below example shows a similar rolling calculation on a
DataFrame using the pairwise option.
>>> matrix = np.array([[51., 35.], [49., 30.], [47., 32.],\
[46., 31.], [50., 36.]])
>>> print(np.corrcoef(matrix[:-1,0], matrix[:-1,1]).round(7))
[[1. 0.6263001]
[0.6263001 1. ]]
>>> print(np.corrcoef(matrix[1:,0], matrix[1:,1]).round(7))
[[1. 0.5553681]
[0.5553681 1. ]]
>>> df = pd.DataFrame(matrix, columns=['X','Y'])
>>> df
X Y
0 51.0 35.0
1 49.0 30.0
2 47.0 32.0
3 46.0 31.0
4 50.0 36.0
>>> df.rolling(4).corr(pairwise=True)
X Y
0 X NaN NaN
Y NaN NaN
1 X NaN NaN
Y NaN NaN
2 X NaN NaN
Y NaN NaN
3 X 1.000000 0.626300
Y 0.626300 1.000000
4 X 1.000000 0.555368
Y 0.555368 1.000000
"""
)
def corr(self, other=None, pairwise=None, **kwargs):
if other is None:
other = self._selected_obj
# only default unset
pairwise = True if pairwise is None else pairwise
other = self._shallow_copy(other)
window = self._get_window(other)
def _get_corr(a, b):
a = a.rolling(
window=window, min_periods=self.min_periods, center=self.center
)
b = b.rolling(
window=window, min_periods=self.min_periods, center=self.center
)
return a.cov(b, **kwargs) / (a.std(**kwargs) * b.std(**kwargs))
return _flex_binary_moment(
self._selected_obj, other._selected_obj, _get_corr, pairwise=bool(pairwise)
)
class Rolling(_Rolling_and_Expanding):
@cache_readonly
def is_datetimelike(self):
return isinstance(
self._on, (ABCDatetimeIndex, ABCTimedeltaIndex, ABCPeriodIndex)
)
@cache_readonly
def _on(self):
if self.on is None:
return self.obj.index
elif isinstance(self.obj, ABCDataFrame) and self.on in self.obj.columns:
return Index(self.obj[self.on])
else:
raise ValueError(
"invalid on specified as {0}, "
"must be a column (if DataFrame) "
"or None".format(self.on)
)
def validate(self):
super().validate()
# we allow rolling on a datetimelike index
if (self.obj.empty or self.is_datetimelike) and isinstance(
self.window, (str, ABCDateOffset, timedelta)
):
self._validate_monotonic()
freq = self._validate_freq()
# we don't allow center
if self.center:
raise NotImplementedError(
"center is not implemented "
"for datetimelike and offset "
"based windows"
)
# this will raise ValueError on non-fixed freqs
self.win_freq = self.window
self.window = freq.nanos
self.win_type = "freq"
# min_periods must be an integer
if self.min_periods is None:
self.min_periods = 1
elif not is_integer(self.window):
raise ValueError("window must be an integer")
elif self.window < 0:
raise ValueError("window must be non-negative")
if not self.is_datetimelike and self.closed is not None:
raise ValueError(
"closed only implemented for datetimelike and offset based windows"
)
def _validate_monotonic(self):
"""
Validate on is_monotonic.
"""
if not self._on.is_monotonic:
formatted = self.on or "index"
raise ValueError("{0} must be monotonic".format(formatted))
def _validate_freq(self):
"""
Validate & return window frequency.
"""
from pandas.tseries.frequencies import to_offset
try:
return to_offset(self.window)
except (TypeError, ValueError):
raise ValueError(
"passed window {0} is not "
"compatible with a datetimelike "
"index".format(self.window)
)
_agg_see_also_doc = dedent(
"""
See Also
--------
Series.rolling
DataFrame.rolling
"""
)
_agg_examples_doc = dedent(
"""
Examples
--------
>>> df = pd.DataFrame(np.random.randn(10, 3), columns=['A', 'B', 'C'])
>>> df
A B C
0 -2.385977 -0.102758 0.438822
1 -1.004295 0.905829 -0.954544
2 0.735167 -0.165272 -1.619346
3 -0.702657 -1.340923 -0.706334
4 -0.246845 0.211596 -0.901819
5 2.463718 3.157577 -1.380906
6 -1.142255 2.340594 -0.039875
7 1.396598 -1.647453 1.677227
8 -0.543425 1.761277 -0.220481
9 -0.640505 0.289374 -1.550670
>>> df.rolling(3).sum()
A B C
0 NaN NaN NaN
1 NaN NaN NaN
2 -2.655105 0.637799 -2.135068
3 -0.971785 -0.600366 -3.280224
4 -0.214334 -1.294599 -3.227500
5 1.514216 2.028250 -2.989060
6 1.074618 5.709767 -2.322600
7 2.718061 3.850718 0.256446
8 -0.289082 2.454418 1.416871
9 0.212668 0.403198 -0.093924
>>> df.rolling(3).agg({'A':'sum', 'B':'min'})
A B
0 NaN NaN
1 NaN NaN
2 -2.655105 -0.165272
3 -0.971785 -1.340923
4 -0.214334 -1.340923
5 1.514216 -1.340923
6 1.074618 0.211596
7 2.718061 -1.647453
8 -0.289082 -1.647453
9 0.212668 -1.647453
"""
)
@Substitution(
see_also=_agg_see_also_doc,
examples=_agg_examples_doc,
versionadded="",
klass="Series/Dataframe",
axis="",
)
@Appender(_shared_docs["aggregate"])
def aggregate(self, arg, *args, **kwargs):
return super().aggregate(arg, *args, **kwargs)
agg = aggregate
@Substitution(name="rolling")
@Appender(_shared_docs["count"])
def count(self):
# different impl for freq counting
if self.is_freq_type:
return self._apply("roll_count", "count")
return super().count()
@Substitution(name="rolling")
@Appender(_shared_docs["apply"])
def apply(self, func, raw=None, args=(), kwargs={}):
return super().apply(func, raw=raw, args=args, kwargs=kwargs)
@Substitution(name="rolling")
@Appender(_shared_docs["sum"])
def sum(self, *args, **kwargs):
nv.validate_rolling_func("sum", args, kwargs)
return super().sum(*args, **kwargs)
@Substitution(name="rolling")
@Appender(_doc_template)
@Appender(_shared_docs["max"])
def max(self, *args, **kwargs):
nv.validate_rolling_func("max", args, kwargs)
return super().max(*args, **kwargs)
@Substitution(name="rolling")
@Appender(_shared_docs["min"])
def min(self, *args, **kwargs):
nv.validate_rolling_func("min", args, kwargs)
return super().min(*args, **kwargs)
@Substitution(name="rolling")
@Appender(_shared_docs["mean"])
def mean(self, *args, **kwargs):
nv.validate_rolling_func("mean", args, kwargs)
return super().mean(*args, **kwargs)
@Substitution(name="rolling")
@Appender(_shared_docs["median"])
def median(self, **kwargs):
return super().median(**kwargs)
@Substitution(name="rolling")
@Appender(_shared_docs["std"])
def std(self, ddof=1, *args, **kwargs):
nv.validate_rolling_func("std", args, kwargs)
return super().std(ddof=ddof, **kwargs)
@Substitution(name="rolling")
@Appender(_shared_docs["var"])
def var(self, ddof=1, *args, **kwargs):
nv.validate_rolling_func("var", args, kwargs)
return super().var(ddof=ddof, **kwargs)
@Substitution(name="rolling")
@Appender(_doc_template)
@Appender(_shared_docs["skew"])
def skew(self, **kwargs):
return super().skew(**kwargs)
_agg_doc = dedent(
"""
Examples
--------
The example below will show a rolling calculation with a window size of
four matching the equivalent function call using `scipy.stats`.
>>> arr = [1, 2, 3, 4, 999]
>>> fmt = "{0:.6f}" # limit the printed precision to 6 digits
>>> import scipy.stats
>>> print(fmt.format(scipy.stats.kurtosis(arr[:-1], bias=False)))
-1.200000
>>> print(fmt.format(scipy.stats.kurtosis(arr[1:], bias=False)))
3.999946
>>> s = pd.Series(arr)
>>> s.rolling(4).kurt()
0 NaN
1 NaN
2 NaN
3 -1.200000
4 3.999946
dtype: float64
"""
)
@Appender(_agg_doc)
@Substitution(name="rolling")
@Appender(_shared_docs["kurt"])
def kurt(self, **kwargs):
return super().kurt(**kwargs)
@Substitution(name="rolling")
@Appender(_shared_docs["quantile"])
def quantile(self, quantile, interpolation="linear", **kwargs):
return super().quantile(
quantile=quantile, interpolation=interpolation, **kwargs
)
@Substitution(name="rolling")
@Appender(_doc_template)
@Appender(_shared_docs["cov"])
def cov(self, other=None, pairwise=None, ddof=1, **kwargs):
return super().cov(other=other, pairwise=pairwise, ddof=ddof, **kwargs)
@Substitution(name="rolling")
@Appender(_shared_docs["corr"])
def corr(self, other=None, pairwise=None, **kwargs):
return super().corr(other=other, pairwise=pairwise, **kwargs)
class RollingGroupby(_GroupByMixin, Rolling):
"""
Provide a rolling groupby implementation.
"""
@property
def _constructor(self):
return Rolling
def _gotitem(self, key, ndim, subset=None):
# we are setting the index on the actual object
# here so our index is carried thru to the selected obj
# when we do the splitting for the groupby
if self.on is not None:
self._groupby.obj = self._groupby.obj.set_index(self._on)
self.on = None
return super()._gotitem(key, ndim, subset=subset)
def _validate_monotonic(self):
"""
Validate that on is monotonic;
we don't care for groupby.rolling
because we have already validated at a higher
level.
"""
pass
class Expanding(_Rolling_and_Expanding):
"""
Provide expanding transformations.
Parameters
----------
min_periods : int, default 1
Minimum number of observations in window required to have a value
(otherwise result is NA).
center : bool, default False
Set the labels at the center of the window.
axis : int or str, default 0
Returns
-------
a Window sub-classed for the particular operation
See Also
--------
rolling : Provides rolling window calculations.
ewm : Provides exponential weighted functions.
Notes
-----
By default, the result is set to the right edge of the window. This can be
changed to the center of the window by setting ``center=True``.
Examples
--------
>>> df = pd.DataFrame({'B': [0, 1, 2, np.nan, 4]})
B
0 0.0
1 1.0
2 2.0
3 NaN
4 4.0
>>> df.expanding(2).sum()
B
0 NaN
1 1.0
2 3.0
3 3.0
4 7.0
"""
_attributes = ["min_periods", "center", "axis"]
def __init__(self, obj, min_periods=1, center=False, axis=0, **kwargs):
super().__init__(obj=obj, min_periods=min_periods, center=center, axis=axis)
@property
def _constructor(self):
return Expanding
def _get_window(self, other=None, **kwargs):
"""
Get the window length over which to perform some operation.
Parameters
----------
other : object, default None
The other object that is involved in the operation.
Such an object is involved for operations like covariance.
Returns
-------
window : int
The window length.
"""
axis = self.obj._get_axis(self.axis)
length = len(axis) + (other is not None) * len(axis)
other = self.min_periods or -1
return max(length, other)
_agg_see_also_doc = dedent(
"""
See Also
--------
DataFrame.expanding.aggregate
DataFrame.rolling.aggregate
DataFrame.aggregate
"""
)
_agg_examples_doc = dedent(
"""
Examples
--------
>>> df = pd.DataFrame(np.random.randn(10, 3), columns=['A', 'B', 'C'])
>>> df
A B C
0 -2.385977 -0.102758 0.438822
1 -1.004295 0.905829 -0.954544
2 0.735167 -0.165272 -1.619346
3 -0.702657 -1.340923 -0.706334
4 -0.246845 0.211596 -0.901819
5 2.463718 3.157577 -1.380906
6 -1.142255 2.340594 -0.039875
7 1.396598 -1.647453 1.677227
8 -0.543425 1.761277 -0.220481
9 -0.640505 0.289374 -1.550670
>>> df.ewm(alpha=0.5).mean()
A B C
0 -2.385977 -0.102758 0.438822
1 -1.464856 0.569633 -0.490089
2 -0.207700 0.149687 -1.135379
3 -0.471677 -0.645305 -0.906555
4 -0.355635 -0.203033 -0.904111
5 1.076417 1.503943 -1.146293
6 -0.041654 1.925562 -0.588728
7 0.680292 0.132049 0.548693
8 0.067236 0.948257 0.163353
9 -0.286980 0.618493 -0.694496
"""
)
@Substitution(
see_also=_agg_see_also_doc,
examples=_agg_examples_doc,
versionadded="",
klass="Series/Dataframe",
axis="",
)
@Appender(_shared_docs["aggregate"])
def aggregate(self, arg, *args, **kwargs):
return super().aggregate(arg, *args, **kwargs)
agg = aggregate
@Substitution(name="expanding")
@Appender(_shared_docs["count"])
def count(self, **kwargs):
return super().count(**kwargs)
@Substitution(name="expanding")
@Appender(_shared_docs["apply"])
def apply(self, func, raw=None, args=(), kwargs={}):
return super().apply(func, raw=raw, args=args, kwargs=kwargs)
@Substitution(name="expanding")
@Appender(_shared_docs["sum"])
def sum(self, *args, **kwargs):
nv.validate_expanding_func("sum", args, kwargs)
return super().sum(*args, **kwargs)
@Substitution(name="expanding")
@Appender(_doc_template)
@Appender(_shared_docs["max"])
def max(self, *args, **kwargs):
nv.validate_expanding_func("max", args, kwargs)
return super().max(*args, **kwargs)
@Substitution(name="expanding")
@Appender(_shared_docs["min"])
def min(self, *args, **kwargs):
nv.validate_expanding_func("min", args, kwargs)
return super().min(*args, **kwargs)
@Substitution(name="expanding")
@Appender(_shared_docs["mean"])
def mean(self, *args, **kwargs):
nv.validate_expanding_func("mean", args, kwargs)
return super().mean(*args, **kwargs)
@Substitution(name="expanding")
@Appender(_shared_docs["median"])
def median(self, **kwargs):
return super().median(**kwargs)
@Substitution(name="expanding")
@Appender(_shared_docs["std"])
def std(self, ddof=1, *args, **kwargs):
nv.validate_expanding_func("std", args, kwargs)
return super().std(ddof=ddof, **kwargs)
@Substitution(name="expanding")
@Appender(_shared_docs["var"])
def var(self, ddof=1, *args, **kwargs):
nv.validate_expanding_func("var", args, kwargs)
return super().var(ddof=ddof, **kwargs)
@Substitution(name="expanding")
@Appender(_doc_template)
@Appender(_shared_docs["skew"])
def skew(self, **kwargs):
return super().skew(**kwargs)
_agg_doc = dedent(
"""
Examples
--------
The example below will show an expanding calculation with a window size of
four matching the equivalent function call using `scipy.stats`.
>>> arr = [1, 2, 3, 4, 999]
>>> import scipy.stats
>>> fmt = "{0:.6f}" # limit the printed precision to 6 digits
>>> print(fmt.format(scipy.stats.kurtosis(arr[:-1], bias=False)))
-1.200000
>>> print(fmt.format(scipy.stats.kurtosis(arr, bias=False)))
4.999874
>>> s = pd.Series(arr)
>>> s.expanding(4).kurt()
0 NaN
1 NaN
2 NaN
3 -1.200000
4 4.999874
dtype: float64
"""
)
@Appender(_agg_doc)
@Substitution(name="expanding")
@Appender(_shared_docs["kurt"])
def kurt(self, **kwargs):
return super().kurt(**kwargs)
@Substitution(name="expanding")
@Appender(_shared_docs["quantile"])
def quantile(self, quantile, interpolation="linear", **kwargs):
return super().quantile(
quantile=quantile, interpolation=interpolation, **kwargs
)
@Substitution(name="expanding")
@Appender(_doc_template)
@Appender(_shared_docs["cov"])
def cov(self, other=None, pairwise=None, ddof=1, **kwargs):
return super().cov(other=other, pairwise=pairwise, ddof=ddof, **kwargs)
@Substitution(name="expanding")
@Appender(_shared_docs["corr"])
def corr(self, other=None, pairwise=None, **kwargs):
return super().corr(other=other, pairwise=pairwise, **kwargs)
class ExpandingGroupby(_GroupByMixin, Expanding):
"""
Provide a expanding groupby implementation.
"""
@property
def _constructor(self):
return Expanding
_bias_template = """
Parameters
----------
bias : bool, default False
Use a standard estimation bias correction.
*args, **kwargs
Arguments and keyword arguments to be passed into func.
"""
_pairwise_template = """
Parameters
----------
other : Series, DataFrame, or ndarray, optional
If not supplied then will default to self and produce pairwise
output.
pairwise : bool, default None
If False then only matching columns between self and other will be
used and the output will be a DataFrame.
If True then all pairwise combinations will be calculated and the
output will be a MultiIndex DataFrame in the case of DataFrame
inputs. In the case of missing elements, only complete pairwise
observations will be used.
bias : bool, default False
Use a standard estimation bias correction.
**kwargs
Keyword arguments to be passed into func.
"""
class EWM(_Rolling):
r"""
Provide exponential weighted functions.
Parameters
----------
com : float, optional
Specify decay in terms of center of mass,
:math:`\alpha = 1 / (1 + com),\text{ for } com \geq 0`.
span : float, optional
Specify decay in terms of span,
:math:`\alpha = 2 / (span + 1),\text{ for } span \geq 1`.
halflife : float, optional
Specify decay in terms of half-life,
:math:`\alpha = 1 - exp(log(0.5) / halflife),\text{for} halflife > 0`.
alpha : float, optional
Specify smoothing factor :math:`\alpha` directly,
:math:`0 < \alpha \leq 1`.
min_periods : int, default 0
Minimum number of observations in window required to have a value
(otherwise result is NA).
adjust : bool, default True
Divide by decaying adjustment factor in beginning periods to account
for imbalance in relative weightings
(viewing EWMA as a moving average).
ignore_na : bool, default False
Ignore missing values when calculating weights;
specify True to reproduce pre-0.15.0 behavior.
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to use. The value 0 identifies the rows, and 1
identifies the columns.
Returns
-------
DataFrame
A Window sub-classed for the particular operation.
See Also
--------
rolling : Provides rolling window calculations.
expanding : Provides expanding transformations.
Notes
-----
Exactly one of center of mass, span, half-life, and alpha must be provided.
Allowed values and relationship between the parameters are specified in the
parameter descriptions above; see the link at the end of this section for
a detailed explanation.
When adjust is True (default), weighted averages are calculated using
weights (1-alpha)**(n-1), (1-alpha)**(n-2), ..., 1-alpha, 1.
When adjust is False, weighted averages are calculated recursively as:
weighted_average[0] = arg[0];
weighted_average[i] = (1-alpha)*weighted_average[i-1] + alpha*arg[i].
When ignore_na is False (default), weights are based on absolute positions.
For example, the weights of x and y used in calculating the final weighted
average of [x, None, y] are (1-alpha)**2 and 1 (if adjust is True), and
(1-alpha)**2 and alpha (if adjust is False).
When ignore_na is True (reproducing pre-0.15.0 behavior), weights are based
on relative positions. For example, the weights of x and y used in
calculating the final weighted average of [x, None, y] are 1-alpha and 1
(if adjust is True), and 1-alpha and alpha (if adjust is False).
More details can be found at
http://pandas.pydata.org/pandas-docs/stable/user_guide/computation.html#exponentially-weighted-windows
Examples
--------
>>> df = pd.DataFrame({'B': [0, 1, 2, np.nan, 4]})
>>> df
B
0 0.0
1 1.0
2 2.0
3 NaN
4 4.0
>>> df.ewm(com=0.5).mean()
B
0 0.000000
1 0.750000
2 1.615385
3 1.615385
4 3.670213
"""
_attributes = ["com", "min_periods", "adjust", "ignore_na", "axis"]
def __init__(
self,
obj,
com=None,
span=None,
halflife=None,
alpha=None,
min_periods=0,
adjust=True,
ignore_na=False,
axis=0,
):
self.obj = obj
self.com = _get_center_of_mass(com, span, halflife, alpha)
self.min_periods = min_periods
self.adjust = adjust
self.ignore_na = ignore_na
self.axis = axis
self.on = None
@property
def _constructor(self):
return EWM
_agg_see_also_doc = dedent(
"""
See Also
--------
pandas.DataFrame.rolling.aggregate
"""
)
_agg_examples_doc = dedent(
"""
Examples
--------
>>> df = pd.DataFrame(np.random.randn(10, 3), columns=['A', 'B', 'C'])
>>> df
A B C
0 -2.385977 -0.102758 0.438822
1 -1.004295 0.905829 -0.954544
2 0.735167 -0.165272 -1.619346
3 -0.702657 -1.340923 -0.706334
4 -0.246845 0.211596 -0.901819
5 2.463718 3.157577 -1.380906
6 -1.142255 2.340594 -0.039875
7 1.396598 -1.647453 1.677227
8 -0.543425 1.761277 -0.220481
9 -0.640505 0.289374 -1.550670
>>> df.ewm(alpha=0.5).mean()
A B C
0 -2.385977 -0.102758 0.438822
1 -1.464856 0.569633 -0.490089
2 -0.207700 0.149687 -1.135379
3 -0.471677 -0.645305 -0.906555
4 -0.355635 -0.203033 -0.904111
5 1.076417 1.503943 -1.146293
6 -0.041654 1.925562 -0.588728
7 0.680292 0.132049 0.548693
8 0.067236 0.948257 0.163353
9 -0.286980 0.618493 -0.694496
"""
)
@Substitution(
see_also=_agg_see_also_doc,
examples=_agg_examples_doc,
versionadded="",
klass="Series/Dataframe",
axis="",
)
@Appender(_shared_docs["aggregate"])
def aggregate(self, arg, *args, **kwargs):
return super().aggregate(arg, *args, **kwargs)
agg = aggregate
def _apply(self, func, **kwargs):
"""
Rolling statistical measure using supplied function. Designed to be
used with passed-in Cython array-based functions.
Parameters
----------
func : str/callable to apply
Returns
-------
y : same type as input argument
"""
blocks, obj = self._create_blocks()
block_list = list(blocks)
results = []
exclude = []
for i, b in enumerate(blocks):
try:
values = self._prep_values(b.values)
except (TypeError, NotImplementedError):
if isinstance(obj, ABCDataFrame):
exclude.extend(b.columns)
del block_list[i]
continue
else:
raise DataError("No numeric types to aggregate")
if values.size == 0:
results.append(values.copy())
continue
# if we have a string function name, wrap it
if isinstance(func, str):
cfunc = getattr(libwindow, func, None)
if cfunc is None:
raise ValueError(
"we do not support this function "
"in libwindow.{func}".format(func=func)
)
def func(arg):
return cfunc(
arg,
self.com,
int(self.adjust),
int(self.ignore_na),
int(self.min_periods),
)
results.append(np.apply_along_axis(func, self.axis, values))
return self._wrap_results(results, block_list, obj, exclude)
@Substitution(name="ewm")
@Appender(_doc_template)
def mean(self, *args, **kwargs):
"""
Exponential weighted moving average.
Parameters
----------
*args, **kwargs
Arguments and keyword arguments to be passed into func.
"""
nv.validate_window_func("mean", args, kwargs)
return self._apply("ewma", **kwargs)
@Substitution(name="ewm")
@Appender(_doc_template)
@Appender(_bias_template)
def std(self, bias=False, *args, **kwargs):
"""
Exponential weighted moving stddev.
"""
nv.validate_window_func("std", args, kwargs)
return _zsqrt(self.var(bias=bias, **kwargs))
vol = std
@Substitution(name="ewm")
@Appender(_doc_template)
@Appender(_bias_template)
def var(self, bias=False, *args, **kwargs):
"""
Exponential weighted moving variance.
"""
nv.validate_window_func("var", args, kwargs)
def f(arg):
return libwindow.ewmcov(
arg,
arg,
self.com,
int(self.adjust),
int(self.ignore_na),
int(self.min_periods),
int(bias),
)
return self._apply(f, **kwargs)
@Substitution(name="ewm")
@Appender(_doc_template)
@Appender(_pairwise_template)
def cov(self, other=None, pairwise=None, bias=False, **kwargs):
"""
Exponential weighted sample covariance.
"""
if other is None:
other = self._selected_obj
# only default unset
pairwise = True if pairwise is None else pairwise
other = self._shallow_copy(other)
def _get_cov(X, Y):
X = self._shallow_copy(X)
Y = self._shallow_copy(Y)
cov = libwindow.ewmcov(
X._prep_values(),
Y._prep_values(),
self.com,
int(self.adjust),
int(self.ignore_na),
int(self.min_periods),
int(bias),
)
return X._wrap_result(cov)
return _flex_binary_moment(
self._selected_obj, other._selected_obj, _get_cov, pairwise=bool(pairwise)
)
@Substitution(name="ewm")
@Appender(_doc_template)
@Appender(_pairwise_template)
def corr(self, other=None, pairwise=None, **kwargs):
"""
Exponential weighted sample correlation.
"""
if other is None:
other = self._selected_obj
# only default unset
pairwise = True if pairwise is None else pairwise
other = self._shallow_copy(other)
def _get_corr(X, Y):
X = self._shallow_copy(X)
Y = self._shallow_copy(Y)
def _cov(x, y):
return libwindow.ewmcov(
x,
y,
self.com,
int(self.adjust),
int(self.ignore_na),
int(self.min_periods),
1,
)
x_values = X._prep_values()
y_values = Y._prep_values()
with np.errstate(all="ignore"):
cov = _cov(x_values, y_values)
x_var = _cov(x_values, x_values)
y_var = _cov(y_values, y_values)
corr = cov / _zsqrt(x_var * y_var)
return X._wrap_result(corr)
return _flex_binary_moment(
self._selected_obj, other._selected_obj, _get_corr, pairwise=bool(pairwise)
)
# Helper Funcs
def _flex_binary_moment(arg1, arg2, f, pairwise=False):
if not (
isinstance(arg1, (np.ndarray, ABCSeries, ABCDataFrame))
and isinstance(arg2, (np.ndarray, ABCSeries, ABCDataFrame))
):
raise TypeError(
"arguments to moment function must be of type "
"np.ndarray/Series/DataFrame"
)
if isinstance(arg1, (np.ndarray, ABCSeries)) and isinstance(
arg2, (np.ndarray, ABCSeries)
):
X, Y = _prep_binary(arg1, arg2)
return f(X, Y)
elif isinstance(arg1, ABCDataFrame):
from pandas import DataFrame
def dataframe_from_int_dict(data, frame_template):
result = DataFrame(data, index=frame_template.index)
if len(result.columns) > 0:
result.columns = frame_template.columns[result.columns]
return result
results = {}
if isinstance(arg2, ABCDataFrame):
if pairwise is False:
if arg1 is arg2:
# special case in order to handle duplicate column names
for i, col in enumerate(arg1.columns):
results[i] = f(arg1.iloc[:, i], arg2.iloc[:, i])
return dataframe_from_int_dict(results, arg1)
else:
if not arg1.columns.is_unique:
raise ValueError("'arg1' columns are not unique")
if not arg2.columns.is_unique:
raise ValueError("'arg2' columns are not unique")
with warnings.catch_warnings(record=True):
warnings.simplefilter("ignore", RuntimeWarning)
X, Y = arg1.align(arg2, join="outer")
X = X + 0 * Y
Y = Y + 0 * X
with warnings.catch_warnings(record=True):
warnings.simplefilter("ignore", RuntimeWarning)
res_columns = arg1.columns.union(arg2.columns)
for col in res_columns:
if col in X and col in Y:
results[col] = f(X[col], Y[col])
return DataFrame(results, index=X.index, columns=res_columns)
elif pairwise is True:
results = defaultdict(dict)
for i, k1 in enumerate(arg1.columns):
for j, k2 in enumerate(arg2.columns):
if j < i and arg2 is arg1:
# Symmetric case
results[i][j] = results[j][i]
else:
results[i][j] = f(
*_prep_binary(arg1.iloc[:, i], arg2.iloc[:, j])
)
from pandas import concat
result_index = arg1.index.union(arg2.index)
if len(result_index):
# construct result frame
result = concat(
[
concat(
[results[i][j] for j, c in enumerate(arg2.columns)],
ignore_index=True,
)
for i, c in enumerate(arg1.columns)
],
ignore_index=True,
axis=1,
)
result.columns = arg1.columns
# set the index and reorder
if arg2.columns.nlevels > 1:
result.index = MultiIndex.from_product(
arg2.columns.levels + [result_index]
)
result = result.reorder_levels([2, 0, 1]).sort_index()
else:
result.index = MultiIndex.from_product(
[range(len(arg2.columns)), range(len(result_index))]
)
result = result.swaplevel(1, 0).sort_index()
result.index = MultiIndex.from_product(
[result_index] + [arg2.columns]
)
else:
# empty result
result = DataFrame(
index=MultiIndex(
levels=[arg1.index, arg2.columns], codes=[[], []]
),
columns=arg2.columns,
dtype="float64",
)
# reset our index names to arg1 names
# reset our column names to arg2 names
# careful not to mutate the original names
result.columns = result.columns.set_names(arg1.columns.names)
result.index = result.index.set_names(
result_index.names + arg2.columns.names
)
return result
else:
raise ValueError("'pairwise' is not True/False")
else:
results = {
i: f(*_prep_binary(arg1.iloc[:, i], arg2))
for i, col in enumerate(arg1.columns)
}
return dataframe_from_int_dict(results, arg1)
else:
return _flex_binary_moment(arg2, arg1, f)
def _get_center_of_mass(comass, span, halflife, alpha):
valid_count = com.count_not_none(comass, span, halflife, alpha)
if valid_count > 1:
raise ValueError("comass, span, halflife, and alpha are mutually exclusive")
# Convert to center of mass; domain checks ensure 0 < alpha <= 1
if comass is not None:
if comass < 0:
raise ValueError("comass must satisfy: comass >= 0")
elif span is not None:
if span < 1:
raise ValueError("span must satisfy: span >= 1")
comass = (span - 1) / 2.0
elif halflife is not None:
if halflife <= 0:
raise ValueError("halflife must satisfy: halflife > 0")
decay = 1 - np.exp(np.log(0.5) / halflife)
comass = 1 / decay - 1
elif alpha is not None:
if alpha <= 0 or alpha > 1:
raise ValueError("alpha must satisfy: 0 < alpha <= 1")
comass = (1.0 - alpha) / alpha
else:
raise ValueError("Must pass one of comass, span, halflife, or alpha")
return float(comass)
def _offset(window, center):
if not is_integer(window):
window = len(window)
offset = (window - 1) / 2.0 if center else 0
try:
return int(offset)
except TypeError:
return offset.astype(int)
def _require_min_periods(p):
def _check_func(minp, window):
if minp is None:
return window
else:
return max(p, minp)
return _check_func
def _use_window(minp, window):
if minp is None:
return window
else:
return minp
def _zsqrt(x):
with np.errstate(all="ignore"):
result = np.sqrt(x)
mask = x < 0
if isinstance(x, ABCDataFrame):
if mask.values.any():
result[mask] = 0
else:
if mask.any():
result[mask] = 0
return result
def _prep_binary(arg1, arg2):
if not isinstance(arg2, type(arg1)):
raise Exception("Input arrays must be of the same type!")
# mask out values, this also makes a common index...
X = arg1 + 0 * arg2
Y = arg2 + 0 * arg1
return X, Y
# Top-level exports
def rolling(obj, win_type=None, **kwds):
if not isinstance(obj, (ABCSeries, ABCDataFrame)):
raise TypeError("invalid type: %s" % type(obj))
if win_type is not None:
return Window(obj, win_type=win_type, **kwds)
return Rolling(obj, **kwds)
rolling.__doc__ = Window.__doc__
def expanding(obj, **kwds):
if not isinstance(obj, (ABCSeries, ABCDataFrame)):
raise TypeError("invalid type: %s" % type(obj))
return Expanding(obj, **kwds)
expanding.__doc__ = Expanding.__doc__
def ewm(obj, **kwds):
if not isinstance(obj, (ABCSeries, ABCDataFrame)):
raise TypeError("invalid type: %s" % type(obj))
return EWM(obj, **kwds)
ewm.__doc__ = EWM.__doc__
"""
Provide a generic structure to support window functions,
similar to how we have a Groupby object.
"""
from collections import defaultdict
from datetime import timedelta
from textwrap import dedent
from typing import Callable, List, Optional, Set, Union
import warnings
import numpy as np
import pandas._libs.window as libwindow
from pandas.compat._optional import import_optional_dependency
from pandas.compat.numpy import function as nv
from pandas.util._decorators import Appender, Substitution, cache_readonly
from pandas.core.dtypes.common import (
ensure_float64,
is_bool,
is_float_dtype,
is_integer,
is_integer_dtype,
is_list_like,
is_scalar,
is_timedelta64_dtype,
needs_i8_conversion,
)
from pandas.core.dtypes.generic import (
ABCDataFrame,
ABCDateOffset,
ABCDatetimeIndex,
ABCPeriodIndex,
ABCSeries,
ABCTimedeltaIndex,
)
from pandas._typing import Axis, FrameOrSeries, Scalar
from pandas.core.base import DataError, PandasObject, SelectionMixin
import pandas.core.common as com
from pandas.core.generic import _shared_docs
from pandas.core.groupby.base import GroupByMixin
from pandas.core.index import Index, MultiIndex, ensure_index
_shared_docs = dict(**_shared_docs)
_doc_template = """
Returns
-------
Series or DataFrame
Return type is determined by the caller.
See Also
--------
Series.%(name)s : Series %(name)s.
DataFrame.%(name)s : DataFrame %(name)s.
"""
class _Window(PandasObject, SelectionMixin):
_attributes = [
"window",
"min_periods",
"center",
"win_type",
"axis",
"on",
"closed",
] # type: List[str]
exclusions = set() # type: Set[str]
def __init__(
self,
obj,
window=None,
min_periods: Optional[int] = None,
center: Optional[bool] = False,
win_type: Optional[str] = None,
axis: Axis = 0,
on: Optional[str] = None,
closed: Optional[str] = None,
**kwargs
):
self.__dict__.update(kwargs)
self.obj = obj
self.on = on
self.closed = closed
self.window = window
self.min_periods = min_periods
self.center = center
self.win_type = win_type
self.win_freq = None
self.axis = obj._get_axis_number(axis) if axis is not None else None
self.validate()
@property
def _constructor(self):
return Window
@property
def is_datetimelike(self) -> Optional[bool]:
return None
@property
def _on(self):
return None
@property
def is_freq_type(self) -> bool:
return self.win_type == "freq"
def validate(self):
if self.center is not None and not is_bool(self.center):
raise ValueError("center must be a boolean")
if self.min_periods is not None and not is_integer(self.min_periods):
raise ValueError("min_periods must be an integer")
if self.closed is not None and self.closed not in [
"right",
"both",
"left",
"neither",
]:
raise ValueError("closed must be 'right', 'left', 'both' or 'neither'")
def _create_blocks(self):
"""
Split data into blocks & return conformed data.
"""
obj = self._selected_obj
# filter out the on from the object
if self.on is not None:
if obj.ndim == 2:
obj = obj.reindex(columns=obj.columns.difference([self.on]), copy=False)
blocks = obj._to_dict_of_blocks(copy=False).values()
return blocks, obj
def _gotitem(self, key, ndim, subset=None):
"""
Sub-classes to define. Return a sliced object.
Parameters
----------
key : str / list of selections
ndim : 1,2
requested ndim of result
subset : object, default None
subset to act on
"""
# create a new object to prevent aliasing
if subset is None:
subset = self.obj
self = self._shallow_copy(subset)
self._reset_cache()
if subset.ndim == 2:
if is_scalar(key) and key in subset or is_list_like(key):
self._selection = key
return self
def __getattr__(self, attr):
if attr in self._internal_names_set:
return object.__getattribute__(self, attr)
if attr in self.obj:
return self[attr]
raise AttributeError(
"%r object has no attribute %r" % (type(self).__name__, attr)
)
def _dir_additions(self):
return self.obj._dir_additions()
def _get_window(self, other=None, **kwargs) -> int:
"""
Returns window length
Parameters
----------
other:
ignored, exists for compatibility
Returns
-------
window : int
"""
return self.window
@property
def _window_type(self) -> str:
return self.__class__.__name__
def __repr__(self) -> str:
"""
Provide a nice str repr of our rolling object.
"""
attrs = (
"{k}={v}".format(k=k, v=getattr(self, k))
for k in self._attributes
if getattr(self, k, None) is not None
)
return "{klass} [{attrs}]".format(
klass=self._window_type, attrs=",".join(attrs)
)
def __iter__(self):
url = "https://github.com/pandas-dev/pandas/issues/11704"
raise NotImplementedError("See issue #11704 {url}".format(url=url))
def _get_index(self) -> Optional[np.ndarray]:
"""
Return integer representations as an ndarray if index is frequency.
Returns
-------
None or ndarray
"""
if self.is_freq_type:
return self._on.asi8
return None
def _prep_values(self, values: Optional[np.ndarray] = None) -> np.ndarray:
"""Convert input to numpy arrays for Cython routines"""
if values is None:
values = getattr(self._selected_obj, "values", self._selected_obj)
# GH #12373 : rolling functions error on float32 data
# make sure the data is coerced to float64
if is_float_dtype(values.dtype):
values = ensure_float64(values)
elif is_integer_dtype(values.dtype):
values = ensure_float64(values)
elif needs_i8_conversion(values.dtype):
raise NotImplementedError(
"ops for {action} for this "
"dtype {dtype} are not "
"implemented".format(action=self._window_type, dtype=values.dtype)
)
else:
try:
values = ensure_float64(values)
except (ValueError, TypeError):
raise TypeError("cannot handle this type -> {0}".format(values.dtype))
# Convert inf to nan for C funcs
inf = np.isinf(values)
if inf.any():
values = np.where(inf, np.nan, values)
return values
def _wrap_result(self, result, block=None, obj=None):
"""
Wrap a single result.
"""
if obj is None:
obj = self._selected_obj
index = obj.index
if isinstance(result, np.ndarray):
# coerce if necessary
if block is not None:
if is_timedelta64_dtype(block.values.dtype):
# TODO: do we know what result.dtype is at this point?
# i.e. can we just do an astype?
from pandas import to_timedelta
result = to_timedelta(result.ravel(), unit="ns").values.reshape(
result.shape
)
if result.ndim == 1:
from pandas import Series
return Series(result, index, name=obj.name)
return type(obj)(result, index=index, columns=block.columns)
return result
def _wrap_results(self, results, blocks, obj, exclude=None) -> FrameOrSeries:
"""
Wrap the results.
Parameters
----------
results : list of ndarrays
blocks : list of blocks
obj : conformed data (may be resampled)
exclude: list of columns to exclude, default to None
"""
from pandas import Series, concat
final = []
for result, block in zip(results, blocks):
result = self._wrap_result(result, block=block, obj=obj)
if result.ndim == 1:
return result
final.append(result)
# if we have an 'on' column
# we want to put it back into the results
# in the same location
columns = self._selected_obj.columns
if self.on is not None and not self._on.equals(obj.index):
name = self._on.name
final.append(Series(self._on, index=obj.index, name=name))
if self._selection is not None:
selection = ensure_index(self._selection)
# need to reorder to include original location of
# the on column (if its not already there)
if name not in selection:
columns = self.obj.columns
indexer = columns.get_indexer(selection.tolist() + [name])
columns = columns.take(sorted(indexer))
# exclude nuisance columns so that they are not reindexed
if exclude is not None and exclude:
columns = [c for c in columns if c not in exclude]
if not columns:
raise DataError("No numeric types to aggregate")
if not len(final):
return obj.astype("float64")
return concat(final, axis=1).reindex(columns=columns, copy=False)
def _center_window(self, result, window) -> np.ndarray:
"""
Center the result in the window.
"""
if self.axis > result.ndim - 1:
raise ValueError("Requested axis is larger then no. of argument dimensions")
offset = _offset(window, True)
if offset > 0:
if isinstance(result, (ABCSeries, ABCDataFrame)):
result = result.slice_shift(-offset, axis=self.axis)
else:
lead_indexer = [slice(None)] * result.ndim
lead_indexer[self.axis] = slice(offset, None)
result = np.copy(result[tuple(lead_indexer)])
return result
def _get_roll_func(
self, cfunc: Callable, check_minp: Callable, index: np.ndarray, **kwargs
) -> Callable:
"""
Wrap rolling function to check values passed.
Parameters
----------
cfunc : callable
Cython function used to calculate rolling statistics
check_minp : callable
function to check minimum period parameter
index : ndarray
used for variable window
Returns
-------
func : callable
"""
def func(arg, window, min_periods=None, closed=None):
minp = check_minp(min_periods, window)
return cfunc(arg, window, minp, index, closed, **kwargs)
return func
def _apply(
self,
func: Union[str, Callable],
name: Optional[str] = None,
window: Optional[Union[int, str]] = None,
center: Optional[bool] = None,
check_minp: Optional[Callable] = None,
**kwargs
):
"""
Rolling statistical measure using supplied function.
Designed to be used with passed-in Cython array-based functions.
Parameters
----------
func : str/callable to apply
name : str, optional
name of this function
window : int/str, default to _get_window()
window length or offset
center : bool, default to self.center
check_minp : function, default to _use_window
**kwargs
additional arguments for rolling function and window function
Returns
-------
y : type of input
"""
if center is None:
center = self.center
if check_minp is None:
check_minp = _use_window
if window is None:
window = self._get_window(**kwargs)
blocks, obj = self._create_blocks()
block_list = list(blocks)
index_as_array = self._get_index()
results = []
exclude = [] # type: List[Scalar]
for i, b in enumerate(blocks):
try:
values = self._prep_values(b.values)
except (TypeError, NotImplementedError):
if isinstance(obj, ABCDataFrame):
exclude.extend(b.columns)
del block_list[i]
continue
else:
raise DataError("No numeric types to aggregate")
if values.size == 0:
results.append(values.copy())
continue
# if we have a string function name, wrap it
if isinstance(func, str):
cfunc = getattr(libwindow, func, None)
if cfunc is None:
raise ValueError(
"we do not support this function "
"in libwindow.{func}".format(func=func)
)
func = self._get_roll_func(cfunc, check_minp, index_as_array, **kwargs)
# calculation function
if center:
offset = _offset(window, center)
additional_nans = np.array([np.NaN] * offset)
def calc(x):
return func(
np.concatenate((x, additional_nans)),
window,
min_periods=self.min_periods,
closed=self.closed,
)
else:
def calc(x):
return func(
x, window, min_periods=self.min_periods, closed=self.closed
)
with np.errstate(all="ignore"):
if values.ndim > 1:
result = np.apply_along_axis(calc, self.axis, values)
else:
result = calc(values)
result = np.asarray(result)
if center:
result = self._center_window(result, window)
results.append(result)
return self._wrap_results(results, block_list, obj, exclude)
def aggregate(self, func, *args, **kwargs):
result, how = self._aggregate(func, *args, **kwargs)
if result is None:
return self.apply(func, raw=False, args=args, kwargs=kwargs)
return result
agg = aggregate
_shared_docs["sum"] = dedent(
"""
Calculate %(name)s sum of given DataFrame or Series.
Parameters
----------
*args, **kwargs
For compatibility with other %(name)s methods. Has no effect
on the computed value.
Returns
-------
Series or DataFrame
Same type as the input, with the same index, containing the
%(name)s sum.
See Also
--------
Series.sum : Reducing sum for Series.
DataFrame.sum : Reducing sum for DataFrame.
Examples
--------
>>> s = pd.Series([1, 2, 3, 4, 5])
>>> s
0 1
1 2
2 3
3 4
4 5
dtype: int64
>>> s.rolling(3).sum()
0 NaN
1 NaN
2 6.0
3 9.0
4 12.0
dtype: float64
>>> s.expanding(3).sum()
0 NaN
1 NaN
2 6.0
3 10.0
4 15.0
dtype: float64
>>> s.rolling(3, center=True).sum()
0 NaN
1 6.0
2 9.0
3 12.0
4 NaN
dtype: float64
For DataFrame, each %(name)s sum is computed column-wise.
>>> df = pd.DataFrame({"A": s, "B": s ** 2})
>>> df
A B
0 1 1
1 2 4
2 3 9
3 4 16
4 5 25
>>> df.rolling(3).sum()
A B
0 NaN NaN
1 NaN NaN
2 6.0 14.0
3 9.0 29.0
4 12.0 50.0
"""
)
_shared_docs["mean"] = dedent(
"""
Calculate the %(name)s mean of the values.
Parameters
----------
*args
Under Review.
**kwargs
Under Review.
Returns
-------
Series or DataFrame
Returned object type is determined by the caller of the %(name)s
calculation.
See Also
--------
Series.%(name)s : Calling object with Series data.
DataFrame.%(name)s : Calling object with DataFrames.
Series.mean : Equivalent method for Series.
DataFrame.mean : Equivalent method for DataFrame.
Examples
--------
The below examples will show rolling mean calculations with window sizes of
two and three, respectively.
>>> s = pd.Series([1, 2, 3, 4])
>>> s.rolling(2).mean()
0 NaN
1 1.5
2 2.5
3 3.5
dtype: float64
>>> s.rolling(3).mean()
0 NaN
1 NaN
2 2.0
3 3.0
dtype: float64
"""
)
class Window(_Window):
"""
Provide rolling window calculations.
Parameters
----------
window : int, or offset
Size of the moving window. This is the number of observations used for
calculating the statistic. Each window will be a fixed size.
If its an offset then this will be the time period of each window. Each
window will be a variable sized based on the observations included in
the time-period. This is only valid for datetimelike indexes.
min_periods : int, default None
Minimum number of observations in window required to have a value
(otherwise result is NA). For a window that is specified by an offset,
`min_periods` will default to 1. Otherwise, `min_periods` will default
to the size of the window.
center : bool, default False
Set the labels at the center of the window.
win_type : str, default None
Provide a window type. If ``None``, all points are evenly weighted.
See the notes below for further information.
on : str, optional
For a DataFrame, a datetime-like column on which to calculate the rolling
window, rather than the DataFrame's index. Provided integer column is
ignored and excluded from result since an integer index is not used to
calculate the rolling window.
axis : int or str, default 0
closed : str, default None
Make the interval closed on the 'right', 'left', 'both' or
'neither' endpoints.
For offset-based windows, it defaults to 'right'.
For fixed windows, defaults to 'both'. Remaining cases not implemented
for fixed windows.
.. versionadded:: 0.20.0
Returns
-------
a Window or Rolling sub-classed for the particular operation
See Also
--------
expanding : Provides expanding transformations.
ewm : Provides exponential weighted functions.
Notes
-----
By default, the result is set to the right edge of the window. This can be
changed to the center of the window by setting ``center=True``.
To learn more about the offsets & frequency strings, please see `this link
<http://pandas.pydata.org/pandas-docs/stable/user_guide/timeseries.html#offset-aliases>`__.
The recognized win_types are:
* ``boxcar``
* ``triang``
* ``blackman``
* ``hamming``
* ``bartlett``
* ``parzen``
* ``bohman``
* ``blackmanharris``
* ``nuttall``
* ``barthann``
* ``kaiser`` (needs beta)
* ``gaussian`` (needs std)
* ``general_gaussian`` (needs power, width)
* ``slepian`` (needs width)
* ``exponential`` (needs tau), center is set to None.
If ``win_type=None`` all points are evenly weighted. To learn more about
different window types see `scipy.signal window functions
<https://docs.scipy.org/doc/scipy/reference/signal.html#window-functions>`__.
Examples
--------
>>> df = pd.DataFrame({'B': [0, 1, 2, np.nan, 4]})
>>> df
B
0 0.0
1 1.0
2 2.0
3 NaN
4 4.0
Rolling sum with a window length of 2, using the 'triang'
window type.
>>> df.rolling(2, win_type='triang').sum()
B
0 NaN
1 0.5
2 1.5
3 NaN
4 NaN
Rolling sum with a window length of 2, min_periods defaults
to the window length.
>>> df.rolling(2).sum()
B
0 NaN
1 1.0
2 3.0
3 NaN
4 NaN
Same as above, but explicitly set the min_periods
>>> df.rolling(2, min_periods=1).sum()
B
0 0.0
1 1.0
2 3.0
3 2.0
4 4.0
A ragged (meaning not-a-regular frequency), time-indexed DataFrame
>>> df = pd.DataFrame({'B': [0, 1, 2, np.nan, 4]},
... index = [pd.Timestamp('20130101 09:00:00'),
... pd.Timestamp('20130101 09:00:02'),
... pd.Timestamp('20130101 09:00:03'),
... pd.Timestamp('20130101 09:00:05'),
... pd.Timestamp('20130101 09:00:06')])
>>> df
B
2013-01-01 09:00:00 0.0
2013-01-01 09:00:02 1.0
2013-01-01 09:00:03 2.0
2013-01-01 09:00:05 NaN
2013-01-01 09:00:06 4.0
Contrasting to an integer rolling window, this will roll a variable
length window corresponding to the time period.
The default for min_periods is 1.
>>> df.rolling('2s').sum()
B
2013-01-01 09:00:00 0.0
2013-01-01 09:00:02 1.0
2013-01-01 09:00:03 3.0
2013-01-01 09:00:05 NaN
2013-01-01 09:00:06 4.0
"""
def validate(self):
super().validate()
window = self.window
if isinstance(window, (list, tuple, np.ndarray)):
pass
elif is_integer(window):
if window <= 0:
raise ValueError("window must be > 0 ")
import_optional_dependency(
"scipy", extra="Scipy is required to generate window weight."
)
import scipy.signal as sig
if not isinstance(self.win_type, str):
raise ValueError("Invalid win_type {0}".format(self.win_type))
if getattr(sig, self.win_type, None) is None:
raise ValueError("Invalid win_type {0}".format(self.win_type))
else:
raise ValueError("Invalid window {0}".format(window))
def _get_window(self, other=None, **kwargs) -> np.ndarray:
"""
Provide validation for the window type, return the window
which has already been validated.
Parameters
----------
other:
ignored, exists for compatibility
Returns
-------
window : ndarray
the window, weights
"""
window = self.window
if isinstance(window, (list, tuple, np.ndarray)):
return com.asarray_tuplesafe(window).astype(float)
elif is_integer(window):
import scipy.signal as sig
# the below may pop from kwargs
def _validate_win_type(win_type, kwargs):
arg_map = {
"kaiser": ["beta"],
"gaussian": ["std"],
"general_gaussian": ["power", "width"],
"slepian": ["width"],
"exponential": ["tau"],
}
if win_type in arg_map:
win_args = _pop_args(win_type, arg_map[win_type], kwargs)
if win_type == "exponential":
# exponential window requires the first arg (center)
# to be set to None (necessary for symmetric window)
win_args.insert(0, None)
return tuple([win_type] + win_args)
return win_type
def _pop_args(win_type, arg_names, kwargs):
msg = "%s window requires %%s" % win_type
all_args = []
for n in arg_names:
if n not in kwargs:
raise ValueError(msg % n)
all_args.append(kwargs.pop(n))
return all_args
win_type = _validate_win_type(self.win_type, kwargs)
# GH #15662. `False` makes symmetric window, rather than periodic.
return sig.get_window(win_type, window, False).astype(float)
def _get_roll_func(
self, cfunc: Callable, check_minp: Callable, index: np.ndarray, **kwargs
) -> Callable:
def func(arg, window, min_periods=None, closed=None):
minp = check_minp(min_periods, len(window))
return cfunc(arg, window, minp)
return func
_agg_see_also_doc = dedent(
"""
See Also
--------
pandas.DataFrame.rolling.aggregate
pandas.DataFrame.aggregate
"""
)
_agg_examples_doc = dedent(
"""
Examples
--------
>>> df = pd.DataFrame(np.random.randn(10, 3), columns=['A', 'B', 'C'])
>>> df
A B C
0 -2.385977 -0.102758 0.438822
1 -1.004295 0.905829 -0.954544
2 0.735167 -0.165272 -1.619346
3 -0.702657 -1.340923 -0.706334
4 -0.246845 0.211596 -0.901819
5 2.463718 3.157577 -1.380906
6 -1.142255 2.340594 -0.039875
7 1.396598 -1.647453 1.677227
8 -0.543425 1.761277 -0.220481
9 -0.640505 0.289374 -1.550670
>>> df.rolling(3, win_type='boxcar').agg('mean')
A B C
0 NaN NaN NaN
1 NaN NaN NaN
2 -0.885035 0.212600 -0.711689
3 -0.323928 -0.200122 -1.093408
4 -0.071445 -0.431533 -1.075833
5 0.504739 0.676083 -0.996353
6 0.358206 1.903256 -0.774200
7 0.906020 1.283573 0.085482
8 -0.096361 0.818139 0.472290
9 0.070889 0.134399 -0.031308
"""
)
@Substitution(
see_also=_agg_see_also_doc,
examples=_agg_examples_doc,
versionadded="",
klass="Series/DataFrame",
axis="",
)
@Appender(_shared_docs["aggregate"])
def aggregate(self, arg, *args, **kwargs):
result, how = self._aggregate(arg, *args, **kwargs)
if result is None:
# these must apply directly
result = arg(self)
return result
agg = aggregate
@Substitution(name="window")
@Appender(_shared_docs["sum"])
def sum(self, *args, **kwargs):
nv.validate_window_func("sum", args, kwargs)
return self._apply("roll_weighted_sum", **kwargs)
@Substitution(name="window")
@Appender(_shared_docs["mean"])
def mean(self, *args, **kwargs):
nv.validate_window_func("mean", args, kwargs)
return self._apply("roll_weighted_mean", **kwargs)
class _GroupByMixin(GroupByMixin):
"""
Provide the groupby facilities.
"""
def __init__(self, obj, *args, **kwargs):
parent = kwargs.pop("parent", None) # noqa
groupby = kwargs.pop("groupby", None)
if groupby is None:
groupby, obj = obj, obj.obj
self._groupby = groupby
self._groupby.mutated = True
self._groupby.grouper.mutated = True
super().__init__(obj, *args, **kwargs)
count = GroupByMixin._dispatch("count")
corr = GroupByMixin._dispatch("corr", other=None, pairwise=None)
cov = GroupByMixin._dispatch("cov", other=None, pairwise=None)
def _apply(
self, func, name=None, window=None, center=None, check_minp=None, **kwargs
):
"""
Dispatch to apply; we are stripping all of the _apply kwargs and
performing the original function call on the grouped object.
"""
def f(x, name=name, *args):
x = self._shallow_copy(x)
if isinstance(name, str):
return getattr(x, name)(*args, **kwargs)
return x.apply(name, *args, **kwargs)
return self._groupby.apply(f)
class _Rolling(_Window):
@property
def _constructor(self):
return Rolling
class _Rolling_and_Expanding(_Rolling):
_shared_docs["count"] = dedent(
r"""
The %(name)s count of any non-NaN observations inside the window.
Returns
-------
Series or DataFrame
Returned object type is determined by the caller of the %(name)s
calculation.
See Also
--------
Series.%(name)s : Calling object with Series data.
DataFrame.%(name)s : Calling object with DataFrames.
DataFrame.count : Count of the full DataFrame.
Examples
--------
>>> s = pd.Series([2, 3, np.nan, 10])
>>> s.rolling(2).count()
0 1.0
1 2.0
2 1.0
3 1.0
dtype: float64
>>> s.rolling(3).count()
0 1.0
1 2.0
2 2.0
3 2.0
dtype: float64
>>> s.rolling(4).count()
0 1.0
1 2.0
2 2.0
3 3.0
dtype: float64
"""
)
def count(self):
blocks, obj = self._create_blocks()
# Validate the index
self._get_index()
window = self._get_window()
window = min(window, len(obj)) if not self.center else window
results = []
for b in blocks:
result = b.notna().astype(int)
result = self._constructor(
result,
window=window,
min_periods=0,
center=self.center,
axis=self.axis,
closed=self.closed,
).sum()
results.append(result)
return self._wrap_results(results, blocks, obj)
_shared_docs["apply"] = dedent(
r"""
The %(name)s function's apply function.
Parameters
----------
func : function
Must produce a single value from an ndarray input if ``raw=True``
or a single value from a Series if ``raw=False``.
raw : bool, default None
* ``False`` : passes each row or column as a Series to the
function.
* ``True`` or ``None`` : the passed function will receive ndarray
objects instead.
If you are just applying a NumPy reduction function this will
achieve much better performance.
The `raw` parameter is required and will show a FutureWarning if
not passed. In the future `raw` will default to False.
.. versionadded:: 0.23.0
*args, **kwargs
Arguments and keyword arguments to be passed into func.
Returns
-------
Series or DataFrame
Return type is determined by the caller.
See Also
--------
Series.%(name)s : Series %(name)s.
DataFrame.%(name)s : DataFrame %(name)s.
"""
)
def apply(self, func, raw=None, args=(), kwargs={}):
from pandas import Series
kwargs.pop("_level", None)
window = self._get_window()
offset = _offset(window, self.center)
index_as_array = self._get_index()
# TODO: default is for backward compat
# change to False in the future
if raw is None:
warnings.warn(
"Currently, 'apply' passes the values as ndarrays to the "
"applied function. In the future, this will change to passing "
"it as Series objects. You need to specify 'raw=True' to keep "
"the current behaviour, and you can pass 'raw=False' to "
"silence this warning",
FutureWarning,
stacklevel=3,
)
raw = True
def f(arg, window, min_periods, closed):
minp = _use_window(min_periods, window)
if not raw:
arg = Series(arg, index=self.obj.index)
return libwindow.roll_generic(
arg,
window,
minp,
index_as_array,
closed,
offset,
func,
raw,
args,
kwargs,
)
return self._apply(f, func, args=args, kwargs=kwargs, center=False, raw=raw)
def sum(self, *args, **kwargs):
nv.validate_window_func("sum", args, kwargs)
return self._apply("roll_sum", "sum", **kwargs)
_shared_docs["max"] = dedent(
"""
Calculate the %(name)s maximum.
Parameters
----------
*args, **kwargs
Arguments and keyword arguments to be passed into func.
"""
)
def max(self, *args, **kwargs):
nv.validate_window_func("max", args, kwargs)
return self._apply("roll_max", "max", **kwargs)
_shared_docs["min"] = dedent(
"""
Calculate the %(name)s minimum.
Parameters
----------
**kwargs
Under Review.
Returns
-------
Series or DataFrame
Returned object type is determined by the caller of the %(name)s
calculation.
See Also
--------
Series.%(name)s : Calling object with a Series.
DataFrame.%(name)s : Calling object with a DataFrame.
Series.min : Similar method for Series.
DataFrame.min : Similar method for DataFrame.
Examples
--------
Performing a rolling minimum with a window size of 3.
>>> s = pd.Series([4, 3, 5, 2, 6])
>>> s.rolling(3).min()
0 NaN
1 NaN
2 3.0
3 2.0
4 2.0
dtype: float64
"""
)
def min(self, *args, **kwargs):
nv.validate_window_func("min", args, kwargs)
return self._apply("roll_min", "min", **kwargs)
def mean(self, *args, **kwargs):
nv.validate_window_func("mean", args, kwargs)
return self._apply("roll_mean", "mean", **kwargs)
_shared_docs["median"] = dedent(
"""
Calculate the %(name)s median.
Parameters
----------
**kwargs
For compatibility with other %(name)s methods. Has no effect
on the computed median.
Returns
-------
Series or DataFrame
Returned type is the same as the original object.
See Also
--------
Series.%(name)s : Calling object with Series data.
DataFrame.%(name)s : Calling object with DataFrames.
Series.median : Equivalent method for Series.
DataFrame.median : Equivalent method for DataFrame.
Examples
--------
Compute the rolling median of a series with a window size of 3.
>>> s = pd.Series([0, 1, 2, 3, 4])
>>> s.rolling(3).median()
0 NaN
1 NaN
2 1.0
3 2.0
4 3.0
dtype: float64
"""
)
def median(self, **kwargs):
return self._apply("roll_median_c", "median", **kwargs)
_shared_docs["std"] = dedent(
"""
Calculate %(name)s standard deviation.
Normalized by N-1 by default. This can be changed using the `ddof`
argument.
Parameters
----------
ddof : int, default 1
Delta Degrees of Freedom. The divisor used in calculations
is ``N - ddof``, where ``N`` represents the number of elements.
*args, **kwargs
For NumPy compatibility. No additional arguments are used.
Returns
-------
Series or DataFrame
Returns the same object type as the caller of the %(name)s calculation.
See Also
--------
Series.%(name)s : Calling object with Series data.
DataFrame.%(name)s : Calling object with DataFrames.
Series.std : Equivalent method for Series.
DataFrame.std : Equivalent method for DataFrame.
numpy.std : Equivalent method for Numpy array.
Notes
-----
The default `ddof` of 1 used in Series.std is different than the default
`ddof` of 0 in numpy.std.
A minimum of one period is required for the rolling calculation.
Examples
--------
>>> s = pd.Series([5, 5, 6, 7, 5, 5, 5])
>>> s.rolling(3).std()
0 NaN
1 NaN
2 0.577350
3 1.000000
4 1.000000
5 1.154701
6 0.000000
dtype: float64
>>> s.expanding(3).std()
0 NaN
1 NaN
2 0.577350
3 0.957427
4 0.894427
5 0.836660
6 0.786796
dtype: float64
"""
)
def std(self, ddof=1, *args, **kwargs):
nv.validate_window_func("std", args, kwargs)
window = self._get_window()
index_as_array = self._get_index()
def f(arg, *args, **kwargs):
minp = _require_min_periods(1)(self.min_periods, window)
return _zsqrt(
libwindow.roll_var(arg, window, minp, index_as_array, self.closed, ddof)
)
return self._apply(
f, "std", check_minp=_require_min_periods(1), ddof=ddof, **kwargs
)
_shared_docs["var"] = dedent(
"""
Calculate unbiased %(name)s variance.
Normalized by N-1 by default. This can be changed using the `ddof`
argument.
Parameters
----------
ddof : int, default 1
Delta Degrees of Freedom. The divisor used in calculations
is ``N - ddof``, where ``N`` represents the number of elements.
*args, **kwargs
For NumPy compatibility. No additional arguments are used.
Returns
-------
Series or DataFrame
Returns the same object type as the caller of the %(name)s calculation.
See Also
--------
Series.%(name)s : Calling object with Series data.
DataFrame.%(name)s : Calling object with DataFrames.
Series.var : Equivalent method for Series.
DataFrame.var : Equivalent method for DataFrame.
numpy.var : Equivalent method for Numpy array.
Notes
-----
The default `ddof` of 1 used in :meth:`Series.var` is different than the
default `ddof` of 0 in :func:`numpy.var`.
A minimum of 1 period is required for the rolling calculation.
Examples
--------
>>> s = pd.Series([5, 5, 6, 7, 5, 5, 5])
>>> s.rolling(3).var()
0 NaN
1 NaN
2 0.333333
3 1.000000
4 1.000000
5 1.333333
6 0.000000
dtype: float64
>>> s.expanding(3).var()
0 NaN
1 NaN
2 0.333333
3 0.916667
4 0.800000
5 0.700000
6 0.619048
dtype: float64
"""
)
def var(self, ddof=1, *args, **kwargs):
nv.validate_window_func("var", args, kwargs)
return self._apply(
"roll_var", "var", check_minp=_require_min_periods(1), ddof=ddof, **kwargs
)
_shared_docs[
"skew"
] = """
Unbiased %(name)s skewness.
Parameters
----------
**kwargs
Keyword arguments to be passed into func.
"""
def skew(self, **kwargs):
return self._apply(
"roll_skew", "skew", check_minp=_require_min_periods(3), **kwargs
)
_shared_docs["kurt"] = dedent(
"""
Calculate unbiased %(name)s kurtosis.
This function uses Fisher's definition of kurtosis without bias.
Parameters
----------
**kwargs
Under Review.
Returns
-------
Series or DataFrame
Returned object type is determined by the caller of the %(name)s
calculation.
See Also
--------
Series.%(name)s : Calling object with Series data.
DataFrame.%(name)s : Calling object with DataFrames.
Series.kurt : Equivalent method for Series.
DataFrame.kurt : Equivalent method for DataFrame.
scipy.stats.skew : Third moment of a probability density.
scipy.stats.kurtosis : Reference SciPy method.
Notes
-----
A minimum of 4 periods is required for the %(name)s calculation.
"""
)
def kurt(self, **kwargs):
return self._apply(
"roll_kurt", "kurt", check_minp=_require_min_periods(4), **kwargs
)
_shared_docs["quantile"] = dedent(
"""
Calculate the %(name)s quantile.
Parameters
----------
quantile : float
Quantile to compute. 0 <= quantile <= 1.
interpolation : {'linear', 'lower', 'higher', 'midpoint', 'nearest'}
.. versionadded:: 0.23.0
This optional parameter specifies the interpolation method to use,
when the desired quantile lies between two data points `i` and `j`:
* linear: `i + (j - i) * fraction`, where `fraction` is the
fractional part of the index surrounded by `i` and `j`.
* lower: `i`.
* higher: `j`.
* nearest: `i` or `j` whichever is nearest.
* midpoint: (`i` + `j`) / 2.
**kwargs:
For compatibility with other %(name)s methods. Has no effect on
the result.
Returns
-------
Series or DataFrame
Returned object type is determined by the caller of the %(name)s
calculation.
See Also
--------
Series.quantile : Computes value at the given quantile over all data
in Series.
DataFrame.quantile : Computes values at the given quantile over
requested axis in DataFrame.
Examples
--------
>>> s = pd.Series([1, 2, 3, 4])
>>> s.rolling(2).quantile(.4, interpolation='lower')
0 NaN
1 1.0
2 2.0
3 3.0
dtype: float64
>>> s.rolling(2).quantile(.4, interpolation='midpoint')
0 NaN
1 1.5
2 2.5
3 3.5
dtype: float64
"""
)
def quantile(self, quantile, interpolation="linear", **kwargs):
window = self._get_window()
index_as_array = self._get_index()
def f(arg, *args, **kwargs):
minp = _use_window(self.min_periods, window)
if quantile == 1.0:
return libwindow.roll_max(
arg, window, minp, index_as_array, self.closed
)
elif quantile == 0.0:
return libwindow.roll_min(
arg, window, minp, index_as_array, self.closed
)
else:
return libwindow.roll_quantile(
arg,
window,
minp,
index_as_array,
self.closed,
quantile,
interpolation,
)
return self._apply(f, "quantile", quantile=quantile, **kwargs)
_shared_docs[
"cov"
] = """
Calculate the %(name)s sample covariance.
Parameters
----------
other : Series, DataFrame, or ndarray, optional
If not supplied then will default to self and produce pairwise
output.
pairwise : bool, default None
If False then only matching columns between self and other will be
used and the output will be a DataFrame.
If True then all pairwise combinations will be calculated and the
output will be a MultiIndexed DataFrame in the case of DataFrame
inputs. In the case of missing elements, only complete pairwise
observations will be used.
ddof : int, default 1
Delta Degrees of Freedom. The divisor used in calculations
is ``N - ddof``, where ``N`` represents the number of elements.
**kwargs
Keyword arguments to be passed into func.
"""
def cov(self, other=None, pairwise=None, ddof=1, **kwargs):
if other is None:
other = self._selected_obj
# only default unset
pairwise = True if pairwise is None else pairwise
other = self._shallow_copy(other)
# GH 16058: offset window
if self.is_freq_type:
window = self.win_freq
else:
window = self._get_window(other)
def _get_cov(X, Y):
# GH #12373 : rolling functions error on float32 data
# to avoid potential overflow, cast the data to float64
X = X.astype("float64")
Y = Y.astype("float64")
mean = lambda x: x.rolling(
window, self.min_periods, center=self.center
).mean(**kwargs)
count = (X + Y).rolling(window=window, center=self.center).count(**kwargs)
bias_adj = count / (count - ddof)
return (mean(X * Y) - mean(X) * mean(Y)) * bias_adj
return _flex_binary_moment(
self._selected_obj, other._selected_obj, _get_cov, pairwise=bool(pairwise)
)
_shared_docs["corr"] = dedent(
"""
Calculate %(name)s correlation.
Parameters
----------
other : Series, DataFrame, or ndarray, optional
If not supplied then will default to self.
pairwise : bool, default None
Calculate pairwise combinations of columns within a
DataFrame. If `other` is not specified, defaults to `True`,
otherwise defaults to `False`.
Not relevant for :class:`~pandas.Series`.
**kwargs
Unused.
Returns
-------
Series or DataFrame
Returned object type is determined by the caller of the
%(name)s calculation.
See Also
--------
Series.%(name)s : Calling object with Series data.
DataFrame.%(name)s : Calling object with DataFrames.
Series.corr : Equivalent method for Series.
DataFrame.corr : Equivalent method for DataFrame.
%(name)s.cov : Similar method to calculate covariance.
numpy.corrcoef : NumPy Pearson's correlation calculation.
Notes
-----
This function uses Pearson's definition of correlation
(https://en.wikipedia.org/wiki/Pearson_correlation_coefficient).
When `other` is not specified, the output will be self correlation (e.g.
all 1's), except for :class:`~pandas.DataFrame` inputs with `pairwise`
set to `True`.
Function will return ``NaN`` for correlations of equal valued sequences;
this is the result of a 0/0 division error.
When `pairwise` is set to `False`, only matching columns between `self` and
`other` will be used.
When `pairwise` is set to `True`, the output will be a MultiIndex DataFrame
with the original index on the first level, and the `other` DataFrame
columns on the second level.
In the case of missing elements, only complete pairwise observations
will be used.
Examples
--------
The below example shows a rolling calculation with a window size of
four matching the equivalent function call using :meth:`numpy.corrcoef`.
>>> v1 = [3, 3, 3, 5, 8]
>>> v2 = [3, 4, 4, 4, 8]
>>> fmt = "{0:.6f}" # limit the printed precision to 6 digits
>>> # numpy returns a 2X2 array, the correlation coefficient
>>> # is the number at entry [0][1]
>>> print(fmt.format(np.corrcoef(v1[:-1], v2[:-1])[0][1]))
0.333333
>>> print(fmt.format(np.corrcoef(v1[1:], v2[1:])[0][1]))
0.916949
>>> s1 = pd.Series(v1)
>>> s2 = pd.Series(v2)
>>> s1.rolling(4).corr(s2)
0 NaN
1 NaN
2 NaN
3 0.333333
4 0.916949
dtype: float64
The below example shows a similar rolling calculation on a
DataFrame using the pairwise option.
>>> matrix = np.array([[51., 35.], [49., 30.], [47., 32.],\
[46., 31.], [50., 36.]])
>>> print(np.corrcoef(matrix[:-1,0], matrix[:-1,1]).round(7))
[[1. 0.6263001]
[0.6263001 1. ]]
>>> print(np.corrcoef(matrix[1:,0], matrix[1:,1]).round(7))
[[1. 0.5553681]
[0.5553681 1. ]]
>>> df = pd.DataFrame(matrix, columns=['X','Y'])
>>> df
X Y
0 51.0 35.0
1 49.0 30.0
2 47.0 32.0
3 46.0 31.0
4 50.0 36.0
>>> df.rolling(4).corr(pairwise=True)
X Y
0 X NaN NaN
Y NaN NaN
1 X NaN NaN
Y NaN NaN
2 X NaN NaN
Y NaN NaN
3 X 1.000000 0.626300
Y 0.626300 1.000000
4 X 1.000000 0.555368
Y 0.555368 1.000000
"""
)
def corr(self, other=None, pairwise=None, **kwargs):
if other is None:
other = self._selected_obj
# only default unset
pairwise = True if pairwise is None else pairwise
other = self._shallow_copy(other)
window = self._get_window(other)
def _get_corr(a, b):
a = a.rolling(
window=window, min_periods=self.min_periods, center=self.center
)
b = b.rolling(
window=window, min_periods=self.min_periods, center=self.center
)
return a.cov(b, **kwargs) / (a.std(**kwargs) * b.std(**kwargs))
return _flex_binary_moment(
self._selected_obj, other._selected_obj, _get_corr, pairwise=bool(pairwise)
)
class Rolling(_Rolling_and_Expanding):
@cache_readonly
def is_datetimelike(self):
return isinstance(
self._on, (ABCDatetimeIndex, ABCTimedeltaIndex, ABCPeriodIndex)
)
@cache_readonly
def _on(self):
if self.on is None:
return self.obj.index
elif isinstance(self.obj, ABCDataFrame) and self.on in self.obj.columns:
return Index(self.obj[self.on])
else:
raise ValueError(
"invalid on specified as {0}, "
"must be a column (if DataFrame) "
"or None".format(self.on)
)
def validate(self):
super().validate()
# we allow rolling on a datetimelike index
if (self.obj.empty or self.is_datetimelike) and isinstance(
self.window, (str, ABCDateOffset, timedelta)
):
self._validate_monotonic()
freq = self._validate_freq()
# we don't allow center
if self.center:
raise NotImplementedError(
"center is not implemented "
"for datetimelike and offset "
"based windows"
)
# this will raise ValueError on non-fixed freqs
self.win_freq = self.window
self.window = freq.nanos
self.win_type = "freq"
# min_periods must be an integer
if self.min_periods is None:
self.min_periods = 1
elif not is_integer(self.window):
raise ValueError("window must be an integer")
elif self.window < 0:
raise ValueError("window must be non-negative")
if not self.is_datetimelike and self.closed is not None:
raise ValueError(
"closed only implemented for datetimelike and offset based windows"
)
def _validate_monotonic(self):
"""
Validate on is_monotonic.
"""
if not self._on.is_monotonic:
formatted = self.on or "index"
raise ValueError("{0} must be monotonic".format(formatted))
def _validate_freq(self):
"""
Validate & return window frequency.
"""
from pandas.tseries.frequencies import to_offset
try:
return to_offset(self.window)
except (TypeError, ValueError):
raise ValueError(
"passed window {0} is not "
"compatible with a datetimelike "
"index".format(self.window)
)
_agg_see_also_doc = dedent(
"""
See Also
--------
Series.rolling
DataFrame.rolling
"""
)
_agg_examples_doc = dedent(
"""
Examples
--------
>>> df = pd.DataFrame(np.random.randn(10, 3), columns=['A', 'B', 'C'])
>>> df
A B C
0 -2.385977 -0.102758 0.438822
1 -1.004295 0.905829 -0.954544
2 0.735167 -0.165272 -1.619346
3 -0.702657 -1.340923 -0.706334
4 -0.246845 0.211596 -0.901819
5 2.463718 3.157577 -1.380906
6 -1.142255 2.340594 -0.039875
7 1.396598 -1.647453 1.677227
8 -0.543425 1.761277 -0.220481
9 -0.640505 0.289374 -1.550670
>>> df.rolling(3).sum()
A B C
0 NaN NaN NaN
1 NaN NaN NaN
2 -2.655105 0.637799 -2.135068
3 -0.971785 -0.600366 -3.280224
4 -0.214334 -1.294599 -3.227500
5 1.514216 2.028250 -2.989060
6 1.074618 5.709767 -2.322600
7 2.718061 3.850718 0.256446
8 -0.289082 2.454418 1.416871
9 0.212668 0.403198 -0.093924
>>> df.rolling(3).agg({'A':'sum', 'B':'min'})
A B
0 NaN NaN
1 NaN NaN
2 -2.655105 -0.165272
3 -0.971785 -1.340923
4 -0.214334 -1.340923
5 1.514216 -1.340923
6 1.074618 0.211596
7 2.718061 -1.647453
8 -0.289082 -1.647453
9 0.212668 -1.647453
"""
)
@Substitution(
see_also=_agg_see_also_doc,
examples=_agg_examples_doc,
versionadded="",
klass="Series/Dataframe",
axis="",
)
@Appender(_shared_docs["aggregate"])
def aggregate(self, arg, *args, **kwargs):
return super().aggregate(arg, *args, **kwargs)
agg = aggregate
@Substitution(name="rolling")
@Appender(_shared_docs["count"])
def count(self):
# different impl for freq counting
if self.is_freq_type:
return self._apply("roll_count", "count")
return super().count()
@Substitution(name="rolling")
@Appender(_shared_docs["apply"])
def apply(self, func, raw=None, args=(), kwargs={}):
return super().apply(func, raw=raw, args=args, kwargs=kwargs)
@Substitution(name="rolling")
@Appender(_shared_docs["sum"])
def sum(self, *args, **kwargs):
nv.validate_rolling_func("sum", args, kwargs)
return super().sum(*args, **kwargs)
@Substitution(name="rolling")
@Appender(_doc_template)
@Appender(_shared_docs["max"])
def max(self, *args, **kwargs):
nv.validate_rolling_func("max", args, kwargs)
return super().max(*args, **kwargs)
@Substitution(name="rolling")
@Appender(_shared_docs["min"])
def min(self, *args, **kwargs):
nv.validate_rolling_func("min", args, kwargs)
return super().min(*args, **kwargs)
@Substitution(name="rolling")
@Appender(_shared_docs["mean"])
def mean(self, *args, **kwargs):
nv.validate_rolling_func("mean", args, kwargs)
return super().mean(*args, **kwargs)
@Substitution(name="rolling")
@Appender(_shared_docs["median"])
def median(self, **kwargs):
return super().median(**kwargs)
@Substitution(name="rolling")
@Appender(_shared_docs["std"])
def std(self, ddof=1, *args, **kwargs):
nv.validate_rolling_func("std", args, kwargs)
return super().std(ddof=ddof, **kwargs)
@Substitution(name="rolling")
@Appender(_shared_docs["var"])
def var(self, ddof=1, *args, **kwargs):
nv.validate_rolling_func("var", args, kwargs)
return super().var(ddof=ddof, **kwargs)
@Substitution(name="rolling")
@Appender(_doc_template)
@Appender(_shared_docs["skew"])
def skew(self, **kwargs):
return super().skew(**kwargs)
_agg_doc = dedent(
"""
Examples
--------
The example below will show a rolling calculation with a window size of
four matching the equivalent function call using `scipy.stats`.
>>> arr = [1, 2, 3, 4, 999]
>>> fmt = "{0:.6f}" # limit the printed precision to 6 digits
>>> import scipy.stats
>>> print(fmt.format(scipy.stats.kurtosis(arr[:-1], bias=False)))
-1.200000
>>> print(fmt.format(scipy.stats.kurtosis(arr[1:], bias=False)))
3.999946
>>> s = pd.Series(arr)
>>> s.rolling(4).kurt()
0 NaN
1 NaN
2 NaN
3 -1.200000
4 3.999946
dtype: float64
"""
)
@Appender(_agg_doc)
@Substitution(name="rolling")
@Appender(_shared_docs["kurt"])
def kurt(self, **kwargs):
return super().kurt(**kwargs)
@Substitution(name="rolling")
@Appender(_shared_docs["quantile"])
def quantile(self, quantile, interpolation="linear", **kwargs):
return super().quantile(
quantile=quantile, interpolation=interpolation, **kwargs
)
@Substitution(name="rolling")
@Appender(_doc_template)
@Appender(_shared_docs["cov"])
def cov(self, other=None, pairwise=None, ddof=1, **kwargs):
return super().cov(other=other, pairwise=pairwise, ddof=ddof, **kwargs)
@Substitution(name="rolling")
@Appender(_shared_docs["corr"])
def corr(self, other=None, pairwise=None, **kwargs):
return super().corr(other=other, pairwise=pairwise, **kwargs)
class RollingGroupby(_GroupByMixin, Rolling):
"""
Provide a rolling groupby implementation.
"""
@property
def _constructor(self):
return Rolling
def _gotitem(self, key, ndim, subset=None):
# we are setting the index on the actual object
# here so our index is carried thru to the selected obj
# when we do the splitting for the groupby
if self.on is not None:
self._groupby.obj = self._groupby.obj.set_index(self._on)
self.on = None
return super()._gotitem(key, ndim, subset=subset)
def _validate_monotonic(self):
"""
Validate that on is monotonic;
we don't care for groupby.rolling
because we have already validated at a higher
level.
"""
pass
class Expanding(_Rolling_and_Expanding):
"""
Provide expanding transformations.
Parameters
----------
min_periods : int, default 1
Minimum number of observations in window required to have a value
(otherwise result is NA).
center : bool, default False
Set the labels at the center of the window.
axis : int or str, default 0
Returns
-------
a Window sub-classed for the particular operation
See Also
--------
rolling : Provides rolling window calculations.
ewm : Provides exponential weighted functions.
Notes
-----
By default, the result is set to the right edge of the window. This can be
changed to the center of the window by setting ``center=True``.
Examples
--------
>>> df = pd.DataFrame({'B': [0, 1, 2, np.nan, 4]})
B
0 0.0
1 1.0
2 2.0
3 NaN
4 4.0
>>> df.expanding(2).sum()
B
0 NaN
1 1.0
2 3.0
3 3.0
4 7.0
"""
_attributes = ["min_periods", "center", "axis"]
def __init__(self, obj, min_periods=1, center=False, axis=0, **kwargs):
super().__init__(obj=obj, min_periods=min_periods, center=center, axis=axis)
@property
def _constructor(self):
return Expanding
def _get_window(self, other=None, **kwargs):
"""
Get the window length over which to perform some operation.
Parameters
----------
other : object, default None
The other object that is involved in the operation.
Such an object is involved for operations like covariance.
Returns
-------
window : int
The window length.
"""
axis = self.obj._get_axis(self.axis)
length = len(axis) + (other is not None) * len(axis)
other = self.min_periods or -1
return max(length, other)
_agg_see_also_doc = dedent(
"""
See Also
--------
DataFrame.expanding.aggregate
DataFrame.rolling.aggregate
DataFrame.aggregate
"""
)
_agg_examples_doc = dedent(
"""
Examples
--------
>>> df = pd.DataFrame(np.random.randn(10, 3), columns=['A', 'B', 'C'])
>>> df
A B C
0 -2.385977 -0.102758 0.438822
1 -1.004295 0.905829 -0.954544
2 0.735167 -0.165272 -1.619346
3 -0.702657 -1.340923 -0.706334
4 -0.246845 0.211596 -0.901819
5 2.463718 3.157577 -1.380906
6 -1.142255 2.340594 -0.039875
7 1.396598 -1.647453 1.677227
8 -0.543425 1.761277 -0.220481
9 -0.640505 0.289374 -1.550670
>>> df.ewm(alpha=0.5).mean()
A B C
0 -2.385977 -0.102758 0.438822
1 -1.464856 0.569633 -0.490089
2 -0.207700 0.149687 -1.135379
3 -0.471677 -0.645305 -0.906555
4 -0.355635 -0.203033 -0.904111
5 1.076417 1.503943 -1.146293
6 -0.041654 1.925562 -0.588728
7 0.680292 0.132049 0.548693
8 0.067236 0.948257 0.163353
9 -0.286980 0.618493 -0.694496
"""
)
@Substitution(
see_also=_agg_see_also_doc,
examples=_agg_examples_doc,
versionadded="",
klass="Series/Dataframe",
axis="",
)
@Appender(_shared_docs["aggregate"])
def aggregate(self, arg, *args, **kwargs):
return super().aggregate(arg, *args, **kwargs)
agg = aggregate
@Substitution(name="expanding")
@Appender(_shared_docs["count"])
def count(self, **kwargs):
return super().count(**kwargs)
@Substitution(name="expanding")
@Appender(_shared_docs["apply"])
def apply(self, func, raw=None, args=(), kwargs={}):
return super().apply(func, raw=raw, args=args, kwargs=kwargs)
@Substitution(name="expanding")
@Appender(_shared_docs["sum"])
def sum(self, *args, **kwargs):
nv.validate_expanding_func("sum", args, kwargs)
return super().sum(*args, **kwargs)
@Substitution(name="expanding")
@Appender(_doc_template)
@Appender(_shared_docs["max"])
def max(self, *args, **kwargs):
nv.validate_expanding_func("max", args, kwargs)
return super().max(*args, **kwargs)
@Substitution(name="expanding")
@Appender(_shared_docs["min"])
def min(self, *args, **kwargs):
nv.validate_expanding_func("min", args, kwargs)
return super().min(*args, **kwargs)
@Substitution(name="expanding")
@Appender(_shared_docs["mean"])
def mean(self, *args, **kwargs):
nv.validate_expanding_func("mean", args, kwargs)
return super().mean(*args, **kwargs)
@Substitution(name="expanding")
@Appender(_shared_docs["median"])
def median(self, **kwargs):
return super().median(**kwargs)
@Substitution(name="expanding")
@Appender(_shared_docs["std"])
def std(self, ddof=1, *args, **kwargs):
nv.validate_expanding_func("std", args, kwargs)
return super().std(ddof=ddof, **kwargs)
@Substitution(name="expanding")
@Appender(_shared_docs["var"])
def var(self, ddof=1, *args, **kwargs):
nv.validate_expanding_func("var", args, kwargs)
return super().var(ddof=ddof, **kwargs)
@Substitution(name="expanding")
@Appender(_doc_template)
@Appender(_shared_docs["skew"])
def skew(self, **kwargs):
return super().skew(**kwargs)
_agg_doc = dedent(
"""
Examples
--------
The example below will show an expanding calculation with a window size of
four matching the equivalent function call using `scipy.stats`.
>>> arr = [1, 2, 3, 4, 999]
>>> import scipy.stats
>>> fmt = "{0:.6f}" # limit the printed precision to 6 digits
>>> print(fmt.format(scipy.stats.kurtosis(arr[:-1], bias=False)))
-1.200000
>>> print(fmt.format(scipy.stats.kurtosis(arr, bias=False)))
4.999874
>>> s = pd.Series(arr)
>>> s.expanding(4).kurt()
0 NaN
1 NaN
2 NaN
3 -1.200000
4 4.999874
dtype: float64
"""
)
@Appender(_agg_doc)
@Substitution(name="expanding")
@Appender(_shared_docs["kurt"])
def kurt(self, **kwargs):
return super().kurt(**kwargs)
@Substitution(name="expanding")
@Appender(_shared_docs["quantile"])
def quantile(self, quantile, interpolation="linear", **kwargs):
return super().quantile(
quantile=quantile, interpolation=interpolation, **kwargs
)
@Substitution(name="expanding")
@Appender(_doc_template)
@Appender(_shared_docs["cov"])
def cov(self, other=None, pairwise=None, ddof=1, **kwargs):
return super().cov(other=other, pairwise=pairwise, ddof=ddof, **kwargs)
@Substitution(name="expanding")
@Appender(_shared_docs["corr"])
def corr(self, other=None, pairwise=None, **kwargs):
return super().corr(other=other, pairwise=pairwise, **kwargs)
class ExpandingGroupby(_GroupByMixin, Expanding):
"""
Provide a expanding groupby implementation.
"""
@property
def _constructor(self):
return Expanding
_bias_template = """
Parameters
----------
bias : bool, default False
Use a standard estimation bias correction.
*args, **kwargs
Arguments and keyword arguments to be passed into func.
"""
_pairwise_template = """
Parameters
----------
other : Series, DataFrame, or ndarray, optional
If not supplied then will default to self and produce pairwise
output.
pairwise : bool, default None
If False then only matching columns between self and other will be
used and the output will be a DataFrame.
If True then all pairwise combinations will be calculated and the
output will be a MultiIndex DataFrame in the case of DataFrame
inputs. In the case of missing elements, only complete pairwise
observations will be used.
bias : bool, default False
Use a standard estimation bias correction.
**kwargs
Keyword arguments to be passed into func.
"""
class EWM(_Rolling):
r"""
Provide exponential weighted functions.
Parameters
----------
com : float, optional
Specify decay in terms of center of mass,
:math:`\alpha = 1 / (1 + com),\text{ for } com \geq 0`.
span : float, optional
Specify decay in terms of span,
:math:`\alpha = 2 / (span + 1),\text{ for } span \geq 1`.
halflife : float, optional
Specify decay in terms of half-life,
:math:`\alpha = 1 - exp(log(0.5) / halflife),\text{for} halflife > 0`.
alpha : float, optional
Specify smoothing factor :math:`\alpha` directly,
:math:`0 < \alpha \leq 1`.
min_periods : int, default 0
Minimum number of observations in window required to have a value
(otherwise result is NA).
adjust : bool, default True
Divide by decaying adjustment factor in beginning periods to account
for imbalance in relative weightings
(viewing EWMA as a moving average).
ignore_na : bool, default False
Ignore missing values when calculating weights;
specify True to reproduce pre-0.15.0 behavior.
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to use. The value 0 identifies the rows, and 1
identifies the columns.
Returns
-------
DataFrame
A Window sub-classed for the particular operation.
See Also
--------
rolling : Provides rolling window calculations.
expanding : Provides expanding transformations.
Notes
-----
Exactly one of center of mass, span, half-life, and alpha must be provided.
Allowed values and relationship between the parameters are specified in the
parameter descriptions above; see the link at the end of this section for
a detailed explanation.
When adjust is True (default), weighted averages are calculated using
weights (1-alpha)**(n-1), (1-alpha)**(n-2), ..., 1-alpha, 1.
When adjust is False, weighted averages are calculated recursively as:
weighted_average[0] = arg[0];
weighted_average[i] = (1-alpha)*weighted_average[i-1] + alpha*arg[i].
When ignore_na is False (default), weights are based on absolute positions.
For example, the weights of x and y used in calculating the final weighted
average of [x, None, y] are (1-alpha)**2 and 1 (if adjust is True), and
(1-alpha)**2 and alpha (if adjust is False).
When ignore_na is True (reproducing pre-0.15.0 behavior), weights are based
on relative positions. For example, the weights of x and y used in
calculating the final weighted average of [x, None, y] are 1-alpha and 1
(if adjust is True), and 1-alpha and alpha (if adjust is False).
More details can be found at
http://pandas.pydata.org/pandas-docs/stable/user_guide/computation.html#exponentially-weighted-windows
Examples
--------
>>> df = pd.DataFrame({'B': [0, 1, 2, np.nan, 4]})
>>> df
B
0 0.0
1 1.0
2 2.0
3 NaN
4 4.0
>>> df.ewm(com=0.5).mean()
B
0 0.000000
1 0.750000
2 1.615385
3 1.615385
4 3.670213
"""
_attributes = ["com", "min_periods", "adjust", "ignore_na", "axis"]
def __init__(
self,
obj,
com=None,
span=None,
halflife=None,
alpha=None,
min_periods=0,
adjust=True,
ignore_na=False,
axis=0,
):
self.obj = obj
self.com = _get_center_of_mass(com, span, halflife, alpha)
self.min_periods = min_periods
self.adjust = adjust
self.ignore_na = ignore_na
self.axis = axis
self.on = None
@property
def _constructor(self):
return EWM
_agg_see_also_doc = dedent(
"""
See Also
--------
pandas.DataFrame.rolling.aggregate
"""
)
_agg_examples_doc = dedent(
"""
Examples
--------
>>> df = pd.DataFrame(np.random.randn(10, 3), columns=['A', 'B', 'C'])
>>> df
A B C
0 -2.385977 -0.102758 0.438822
1 -1.004295 0.905829 -0.954544
2 0.735167 -0.165272 -1.619346
3 -0.702657 -1.340923 -0.706334
4 -0.246845 0.211596 -0.901819
5 2.463718 3.157577 -1.380906
6 -1.142255 2.340594 -0.039875
7 1.396598 -1.647453 1.677227
8 -0.543425 1.761277 -0.220481
9 -0.640505 0.289374 -1.550670
>>> df.ewm(alpha=0.5).mean()
A B C
0 -2.385977 -0.102758 0.438822
1 -1.464856 0.569633 -0.490089
2 -0.207700 0.149687 -1.135379
3 -0.471677 -0.645305 -0.906555
4 -0.355635 -0.203033 -0.904111
5 1.076417 1.503943 -1.146293
6 -0.041654 1.925562 -0.588728
7 0.680292 0.132049 0.548693
8 0.067236 0.948257 0.163353
9 -0.286980 0.618493 -0.694496
"""
)
@Substitution(
see_also=_agg_see_also_doc,
examples=_agg_examples_doc,
versionadded="",
klass="Series/Dataframe",
axis="",
)
@Appender(_shared_docs["aggregate"])
def aggregate(self, arg, *args, **kwargs):
return super().aggregate(arg, *args, **kwargs)
agg = aggregate
def _apply(self, func, **kwargs):
"""
Rolling statistical measure using supplied function. Designed to be
used with passed-in Cython array-based functions.
Parameters
----------
func : str/callable to apply
Returns
-------
y : same type as input argument
"""
blocks, obj = self._create_blocks()
block_list = list(blocks)
results = []
exclude = []
for i, b in enumerate(blocks):
try:
values = self._prep_values(b.values)
except (TypeError, NotImplementedError):
if isinstance(obj, ABCDataFrame):
exclude.extend(b.columns)
del block_list[i]
continue
else:
raise DataError("No numeric types to aggregate")
if values.size == 0:
results.append(values.copy())
continue
# if we have a string function name, wrap it
if isinstance(func, str):
cfunc = getattr(libwindow, func, None)
if cfunc is None:
raise ValueError(
"we do not support this function "
"in libwindow.{func}".format(func=func)
)
def func(arg):
return cfunc(
arg,
self.com,
int(self.adjust),
int(self.ignore_na),
int(self.min_periods),
)
results.append(np.apply_along_axis(func, self.axis, values))
return self._wrap_results(results, block_list, obj, exclude)
@Substitution(name="ewm")
@Appender(_doc_template)
def mean(self, *args, **kwargs):
"""
Exponential weighted moving average.
Parameters
----------
*args, **kwargs
Arguments and keyword arguments to be passed into func.
"""
nv.validate_window_func("mean", args, kwargs)
return self._apply("ewma", **kwargs)
@Substitution(name="ewm")
@Appender(_doc_template)
@Appender(_bias_template)
def std(self, bias=False, *args, **kwargs):
"""
Exponential weighted moving stddev.
"""
nv.validate_window_func("std", args, kwargs)
return _zsqrt(self.var(bias=bias, **kwargs))
vol = std
@Substitution(name="ewm")
@Appender(_doc_template)
@Appender(_bias_template)
def var(self, bias=False, *args, **kwargs):
"""
Exponential weighted moving variance.
"""
nv.validate_window_func("var", args, kwargs)
def f(arg):
return libwindow.ewmcov(
arg,
arg,
self.com,
int(self.adjust),
int(self.ignore_na),
int(self.min_periods),
int(bias),
)
return self._apply(f, **kwargs)
@Substitution(name="ewm")
@Appender(_doc_template)
@Appender(_pairwise_template)
def cov(self, other=None, pairwise=None, bias=False, **kwargs):
"""
Exponential weighted sample covariance.
"""
if other is None:
other = self._selected_obj
# only default unset
pairwise = True if pairwise is None else pairwise
other = self._shallow_copy(other)
def _get_cov(X, Y):
X = self._shallow_copy(X)
Y = self._shallow_copy(Y)
cov = libwindow.ewmcov(
X._prep_values(),
Y._prep_values(),
self.com,
int(self.adjust),
int(self.ignore_na),
int(self.min_periods),
int(bias),
)
return X._wrap_result(cov)
return _flex_binary_moment(
self._selected_obj, other._selected_obj, _get_cov, pairwise=bool(pairwise)
)
@Substitution(name="ewm")
@Appender(_doc_template)
@Appender(_pairwise_template)
def corr(self, other=None, pairwise=None, **kwargs):
"""
Exponential weighted sample correlation.
"""
if other is None:
other = self._selected_obj
# only default unset
pairwise = True if pairwise is None else pairwise
other = self._shallow_copy(other)
def _get_corr(X, Y):
X = self._shallow_copy(X)
Y = self._shallow_copy(Y)
def _cov(x, y):
return libwindow.ewmcov(
x,
y,
self.com,
int(self.adjust),
int(self.ignore_na),
int(self.min_periods),
1,
)
x_values = X._prep_values()
y_values = Y._prep_values()
with np.errstate(all="ignore"):
cov = _cov(x_values, y_values)
x_var = _cov(x_values, x_values)
y_var = _cov(y_values, y_values)
corr = cov / _zsqrt(x_var * y_var)
return X._wrap_result(corr)
return _flex_binary_moment(
self._selected_obj, other._selected_obj, _get_corr, pairwise=bool(pairwise)
)
# Helper Funcs
def _flex_binary_moment(arg1, arg2, f, pairwise=False):
if not (
isinstance(arg1, (np.ndarray, ABCSeries, ABCDataFrame))
and isinstance(arg2, (np.ndarray, ABCSeries, ABCDataFrame))
):
raise TypeError(
"arguments to moment function must be of type "
"np.ndarray/Series/DataFrame"
)
if isinstance(arg1, (np.ndarray, ABCSeries)) and isinstance(
arg2, (np.ndarray, ABCSeries)
):
X, Y = _prep_binary(arg1, arg2)
return f(X, Y)
elif isinstance(arg1, ABCDataFrame):
from pandas import DataFrame
def dataframe_from_int_dict(data, frame_template):
result = DataFrame(data, index=frame_template.index)
if len(result.columns) > 0:
result.columns = frame_template.columns[result.columns]
return result
results = {}
if isinstance(arg2, ABCDataFrame):
if pairwise is False:
if arg1 is arg2:
# special case in order to handle duplicate column names
for i, col in enumerate(arg1.columns):
results[i] = f(arg1.iloc[:, i], arg2.iloc[:, i])
return dataframe_from_int_dict(results, arg1)
else:
if not arg1.columns.is_unique:
raise ValueError("'arg1' columns are not unique")
if not arg2.columns.is_unique:
raise ValueError("'arg2' columns are not unique")
with warnings.catch_warnings(record=True):
warnings.simplefilter("ignore", RuntimeWarning)
X, Y = arg1.align(arg2, join="outer")
X = X + 0 * Y
Y = Y + 0 * X
with warnings.catch_warnings(record=True):
warnings.simplefilter("ignore", RuntimeWarning)
res_columns = arg1.columns.union(arg2.columns)
for col in res_columns:
if col in X and col in Y:
results[col] = f(X[col], Y[col])
return DataFrame(results, index=X.index, columns=res_columns)
elif pairwise is True:
results = defaultdict(dict)
for i, k1 in enumerate(arg1.columns):
for j, k2 in enumerate(arg2.columns):
if j < i and arg2 is arg1:
# Symmetric case
results[i][j] = results[j][i]
else:
results[i][j] = f(
*_prep_binary(arg1.iloc[:, i], arg2.iloc[:, j])
)
from pandas import concat
result_index = arg1.index.union(arg2.index)
if len(result_index):
# construct result frame
result = concat(
[
concat(
[results[i][j] for j, c in enumerate(arg2.columns)],
ignore_index=True,
)
for i, c in enumerate(arg1.columns)
],
ignore_index=True,
axis=1,
)
result.columns = arg1.columns
# set the index and reorder
if arg2.columns.nlevels > 1:
result.index = MultiIndex.from_product(
arg2.columns.levels + [result_index]
)
result = result.reorder_levels([2, 0, 1]).sort_index()
else:
result.index = MultiIndex.from_product(
[range(len(arg2.columns)), range(len(result_index))]
)
result = result.swaplevel(1, 0).sort_index()
result.index = MultiIndex.from_product(
[result_index] + [arg2.columns]
)
else:
# empty result
result = DataFrame(
index=MultiIndex(
levels=[arg1.index, arg2.columns], codes=[[], []]
),
columns=arg2.columns,
dtype="float64",
)
# reset our index names to arg1 names
# reset our column names to arg2 names
# careful not to mutate the original names
result.columns = result.columns.set_names(arg1.columns.names)
result.index = result.index.set_names(
result_index.names + arg2.columns.names
)
return result
else:
raise ValueError("'pairwise' is not True/False")
else:
results = {
i: f(*_prep_binary(arg1.iloc[:, i], arg2))
for i, col in enumerate(arg1.columns)
}
return dataframe_from_int_dict(results, arg1)
else:
return _flex_binary_moment(arg2, arg1, f)
def _get_center_of_mass(comass, span, halflife, alpha):
valid_count = com.count_not_none(comass, span, halflife, alpha)
if valid_count > 1:
raise ValueError("comass, span, halflife, and alpha are mutually exclusive")
# Convert to center of mass; domain checks ensure 0 < alpha <= 1
if comass is not None:
if comass < 0:
raise ValueError("comass must satisfy: comass >= 0")
elif span is not None:
if span < 1:
raise ValueError("span must satisfy: span >= 1")
comass = (span - 1) / 2.0
elif halflife is not None:
if halflife <= 0:
raise ValueError("halflife must satisfy: halflife > 0")
decay = 1 - np.exp(np.log(0.5) / halflife)
comass = 1 / decay - 1
elif alpha is not None:
if alpha <= 0 or alpha > 1:
raise ValueError("alpha must satisfy: 0 < alpha <= 1")
comass = (1.0 - alpha) / alpha
else:
raise ValueError("Must pass one of comass, span, halflife, or alpha")
return float(comass)
def _offset(window, center):
if not is_integer(window):
window = len(window)
offset = (window - 1) / 2.0 if center else 0
try:
return int(offset)
except TypeError:
return offset.astype(int)
def _require_min_periods(p):
def _check_func(minp, window):
if minp is None:
return window
else:
return max(p, minp)
return _check_func
def _use_window(minp, window):
if minp is None:
return window
else:
return minp
def _zsqrt(x):
with np.errstate(all="ignore"):
result = np.sqrt(x)
mask = x < 0
if isinstance(x, ABCDataFrame):
if mask.values.any():
result[mask] = 0
else:
if mask.any():
result[mask] = 0
return result
def _prep_binary(arg1, arg2):
if not isinstance(arg2, type(arg1)):
raise Exception("Input arrays must be of the same type!")
# mask out values, this also makes a common index...
X = arg1 + 0 * arg2
Y = arg2 + 0 * arg1
return X, Y
# Top-level exports
def rolling(obj, win_type=None, **kwds):
if not isinstance(obj, (ABCSeries, ABCDataFrame)):
raise TypeError("invalid type: %s" % type(obj))
if win_type is not None:
return Window(obj, win_type=win_type, **kwds)
return Rolling(obj, **kwds)
rolling.__doc__ = Window.__doc__
def expanding(obj, **kwds):
if not isinstance(obj, (ABCSeries, ABCDataFrame)):
raise TypeError("invalid type: %s" % type(obj))
return Expanding(obj, **kwds)
expanding.__doc__ = Expanding.__doc__
def ewm(obj, **kwds):
if not isinstance(obj, (ABCSeries, ABCDataFrame)):
raise TypeError("invalid type: %s" % type(obj))
return EWM(obj, **kwds)
ewm.__doc__ = EWM.__doc__
| BugsInPy/BugsInPy/temp/projects/pandas/bug-163-fixed/pandas/pandas/core/window.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-163-buggy/pandas/pandas/core/window.py |
pandas-bug-125 | import operator
from shutil import get_terminal_size
import textwrap
from typing import Type, Union, cast
from warnings import warn
import numpy as np
from pandas._config import get_option
from pandas._libs import algos as libalgos, hashtable as htable
from pandas.compat.numpy import function as nv
from pandas.util._decorators import (
Appender,
Substitution,
cache_readonly,
deprecate_kwarg,
)
from pandas.util._validators import validate_bool_kwarg, validate_fillna_kwargs
from pandas.core.dtypes.cast import coerce_indexer_dtype, maybe_infer_to_datetimelike
from pandas.core.dtypes.common import (
ensure_int64,
ensure_object,
ensure_platform_int,
is_categorical_dtype,
is_datetime64_dtype,
is_dict_like,
is_dtype_equal,
is_extension_array_dtype,
is_float_dtype,
is_integer_dtype,
is_iterator,
is_list_like,
is_object_dtype,
is_scalar,
is_sequence,
is_timedelta64_dtype,
needs_i8_conversion,
)
from pandas.core.dtypes.dtypes import CategoricalDtype
from pandas.core.dtypes.generic import ABCIndexClass, ABCSeries
from pandas.core.dtypes.inference import is_hashable
from pandas.core.dtypes.missing import isna, notna
from pandas._typing import ArrayLike, Dtype, Ordered
from pandas.core import ops
from pandas.core.accessor import PandasDelegate, delegate_names
import pandas.core.algorithms as algorithms
from pandas.core.algorithms import _get_data_algo, factorize, take, take_1d, unique1d
from pandas.core.base import NoNewAttributesMixin, PandasObject, _shared_docs
import pandas.core.common as com
from pandas.core.construction import array, extract_array, sanitize_array
from pandas.core.missing import interpolate_2d
from pandas.core.ops.common import unpack_zerodim_and_defer
from pandas.core.sorting import nargsort
from pandas.io.formats import console
from .base import ExtensionArray, _extension_array_shared_docs, try_cast_to_ea
_take_msg = textwrap.dedent(
"""\
Interpreting negative values in 'indexer' as missing values.
In the future, this will change to meaning positional indices
from the right.
Use 'allow_fill=True' to retain the previous behavior and silence this
warning.
Use 'allow_fill=False' to accept the new behavior."""
)
def _cat_compare_op(op):
opname = "__{op}__".format(op=op.__name__)
@unpack_zerodim_and_defer(opname)
def f(self, other):
# On python2, you can usually compare any type to any type, and
# Categoricals can be seen as a custom type, but having different
# results depending whether categories are the same or not is kind of
# insane, so be a bit stricter here and use the python3 idea of
# comparing only things of equal type.
if is_list_like(other) and len(other) != len(self):
# TODO: Could this fail if the categories are listlike objects?
raise ValueError("Lengths must match.")
if not self.ordered:
if opname in ["__lt__", "__gt__", "__le__", "__ge__"]:
raise TypeError(
"Unordered Categoricals can only compare equality or not"
)
if isinstance(other, Categorical):
# Two Categoricals can only be be compared if the categories are
# the same (maybe up to ordering, depending on ordered)
msg = "Categoricals can only be compared if 'categories' are the same."
if len(self.categories) != len(other.categories):
raise TypeError(msg + " Categories are different lengths")
elif self.ordered and not (self.categories == other.categories).all():
raise TypeError(msg)
elif not set(self.categories) == set(other.categories):
raise TypeError(msg)
if not (self.ordered == other.ordered):
raise TypeError(
"Categoricals can only be compared if 'ordered' is the same"
)
if not self.ordered and not self.categories.equals(other.categories):
# both unordered and different order
other_codes = _get_codes_for_values(other, self.categories)
else:
other_codes = other._codes
mask = (self._codes == -1) | (other_codes == -1)
f = getattr(self._codes, opname)
ret = f(other_codes)
if mask.any():
# In other series, the leads to False, so do that here too
ret[mask] = False
return ret
if is_scalar(other):
if other in self.categories:
i = self.categories.get_loc(other)
ret = getattr(self._codes, opname)(i)
# check for NaN in self
mask = self._codes == -1
ret[mask] = False
return ret
else:
if opname == "__eq__":
return np.repeat(False, len(self))
elif opname == "__ne__":
return np.repeat(True, len(self))
else:
msg = (
"Cannot compare a Categorical for op {op} with a "
"scalar, which is not a category."
)
raise TypeError(msg.format(op=opname))
else:
# allow categorical vs object dtype array comparisons for equality
# these are only positional comparisons
if opname in ["__eq__", "__ne__"]:
return getattr(np.array(self), opname)(np.array(other))
msg = (
"Cannot compare a Categorical for op {op} with type {typ}."
"\nIf you want to compare values, use 'np.asarray(cat) "
"<op> other'."
)
raise TypeError(msg.format(op=opname, typ=type(other)))
f.__name__ = opname
return f
def contains(cat, key, container):
"""
Helper for membership check for ``key`` in ``cat``.
This is a helper method for :method:`__contains__`
and :class:`CategoricalIndex.__contains__`.
Returns True if ``key`` is in ``cat.categories`` and the
location of ``key`` in ``categories`` is in ``container``.
Parameters
----------
cat : :class:`Categorical`or :class:`categoricalIndex`
key : a hashable object
The key to check membership for.
container : Container (e.g. list-like or mapping)
The container to check for membership in.
Returns
-------
is_in : bool
True if ``key`` is in ``self.categories`` and location of
``key`` in ``categories`` is in ``container``, else False.
Notes
-----
This method does not check for NaN values. Do that separately
before calling this method.
"""
hash(key)
# get location of key in categories.
# If a KeyError, the key isn't in categories, so logically
# can't be in container either.
try:
loc = cat.categories.get_loc(key)
except (KeyError, TypeError):
return False
# loc is the location of key in categories, but also the *value*
# for key in container. So, `key` may be in categories,
# but still not in `container`. Example ('b' in categories,
# but not in values):
# 'b' in Categorical(['a'], categories=['a', 'b']) # False
if is_scalar(loc):
return loc in container
else:
# if categories is an IntervalIndex, loc is an array.
return any(loc_ in container for loc_ in loc)
_codes_doc = """
The category codes of this categorical.
Level codes are an array if integer which are the positions of the real
values in the categories array.
There is not setter, use the other categorical methods and the normal item
setter to change values in the categorical.
"""
class Categorical(ExtensionArray, PandasObject):
"""
Represent a categorical variable in classic R / S-plus fashion.
`Categoricals` can only take on only a limited, and usually fixed, number
of possible values (`categories`). In contrast to statistical categorical
variables, a `Categorical` might have an order, but numerical operations
(additions, divisions, ...) are not possible.
All values of the `Categorical` are either in `categories` or `np.nan`.
Assigning values outside of `categories` will raise a `ValueError`. Order
is defined by the order of the `categories`, not lexical order of the
values.
Parameters
----------
values : list-like
The values of the categorical. If categories are given, values not in
categories will be replaced with NaN.
categories : Index-like (unique), optional
The unique categories for this categorical. If not given, the
categories are assumed to be the unique values of `values` (sorted, if
possible, otherwise in the order in which they appear).
ordered : bool, default False
Whether or not this categorical is treated as a ordered categorical.
If True, the resulting categorical will be ordered.
An ordered categorical respects, when sorted, the order of its
`categories` attribute (which in turn is the `categories` argument, if
provided).
dtype : CategoricalDtype
An instance of ``CategoricalDtype`` to use for this categorical
.. versionadded:: 0.21.0
Attributes
----------
categories : Index
The categories of this categorical
codes : ndarray
The codes (integer positions, which point to the categories) of this
categorical, read only.
ordered : bool
Whether or not this Categorical is ordered.
dtype : CategoricalDtype
The instance of ``CategoricalDtype`` storing the ``categories``
and ``ordered``.
.. versionadded:: 0.21.0
Methods
-------
from_codes
__array__
Raises
------
ValueError
If the categories do not validate.
TypeError
If an explicit ``ordered=True`` is given but no `categories` and the
`values` are not sortable.
See Also
--------
CategoricalDtype : Type for categorical data.
CategoricalIndex : An Index with an underlying ``Categorical``.
Notes
-----
See the `user guide
<http://pandas.pydata.org/pandas-docs/stable/user_guide/categorical.html>`_
for more.
Examples
--------
>>> pd.Categorical([1, 2, 3, 1, 2, 3])
[1, 2, 3, 1, 2, 3]
Categories (3, int64): [1, 2, 3]
>>> pd.Categorical(['a', 'b', 'c', 'a', 'b', 'c'])
[a, b, c, a, b, c]
Categories (3, object): [a, b, c]
Ordered `Categoricals` can be sorted according to the custom order
of the categories and can have a min and max value.
>>> c = pd.Categorical(['a', 'b', 'c', 'a', 'b', 'c'], ordered=True,
... categories=['c', 'b', 'a'])
>>> c
[a, b, c, a, b, c]
Categories (3, object): [c < b < a]
>>> c.min()
'c'
"""
# For comparisons, so that numpy uses our implementation if the compare
# ops, which raise
__array_priority__ = 1000
_dtype = CategoricalDtype(ordered=False)
# tolist is not actually deprecated, just suppressed in the __dir__
_deprecations = PandasObject._deprecations | frozenset(
["tolist", "itemsize", "get_values"]
)
_typ = "categorical"
def __init__(
self, values, categories=None, ordered=None, dtype=None, fastpath=False
):
dtype = CategoricalDtype._from_values_or_dtype(
values, categories, ordered, dtype
)
# At this point, dtype is always a CategoricalDtype, but
# we may have dtype.categories be None, and we need to
# infer categories in a factorization step further below
if fastpath:
self._codes = coerce_indexer_dtype(values, dtype.categories)
self._dtype = self._dtype.update_dtype(dtype)
return
# null_mask indicates missing values we want to exclude from inference.
# This means: only missing values in list-likes (not arrays/ndframes).
null_mask = np.array(False)
# sanitize input
if is_categorical_dtype(values):
if dtype.categories is None:
dtype = CategoricalDtype(values.categories, dtype._ordered)
elif not isinstance(values, (ABCIndexClass, ABCSeries)):
# sanitize_array coerces np.nan to a string under certain versions
# of numpy
values = maybe_infer_to_datetimelike(values, convert_dates=True)
if not isinstance(values, np.ndarray):
values = _convert_to_list_like(values)
# By convention, empty lists result in object dtype:
if len(values) == 0:
sanitize_dtype = "object"
else:
sanitize_dtype = None
null_mask = isna(values)
if null_mask.any():
values = [values[idx] for idx in np.where(~null_mask)[0]]
values = sanitize_array(values, None, dtype=sanitize_dtype)
if dtype.categories is None:
try:
codes, categories = factorize(values, sort=True)
except TypeError:
codes, categories = factorize(values, sort=False)
if dtype._ordered:
# raise, as we don't have a sortable data structure and so
# the user should give us one by specifying categories
raise TypeError(
"'values' is not ordered, please "
"explicitly specify the categories order "
"by passing in a categories argument."
)
except ValueError:
# FIXME
raise NotImplementedError(
"> 1 ndim Categorical are not supported at this time"
)
# we're inferring from values
dtype = CategoricalDtype(categories, dtype._ordered)
elif is_categorical_dtype(values):
old_codes = (
values._values.codes if isinstance(values, ABCSeries) else values.codes
)
codes = _recode_for_categories(
old_codes, values.dtype.categories, dtype.categories
)
else:
codes = _get_codes_for_values(values, dtype.categories)
if null_mask.any():
# Reinsert -1 placeholders for previously removed missing values
full_codes = -np.ones(null_mask.shape, dtype=codes.dtype)
full_codes[~null_mask] = codes
codes = full_codes
self._dtype = self._dtype.update_dtype(dtype)
self._codes = coerce_indexer_dtype(codes, dtype.categories)
@property
def categories(self):
"""
The categories of this categorical.
Setting assigns new values to each category (effectively a rename of
each individual category).
The assigned value has to be a list-like object. All items must be
unique and the number of items in the new categories must be the same
as the number of items in the old categories.
Assigning to `categories` is a inplace operation!
Raises
------
ValueError
If the new categories do not validate as categories or if the
number of new categories is unequal the number of old categories
See Also
--------
rename_categories
reorder_categories
add_categories
remove_categories
remove_unused_categories
set_categories
"""
return self.dtype.categories
@categories.setter
def categories(self, categories):
new_dtype = CategoricalDtype(categories, ordered=self.ordered)
if self.dtype.categories is not None and len(self.dtype.categories) != len(
new_dtype.categories
):
raise ValueError(
"new categories need to have the same number of "
"items as the old categories!"
)
self._dtype = new_dtype
@property
def ordered(self) -> Ordered:
"""
Whether the categories have an ordered relationship.
"""
return self.dtype._ordered
@property
def dtype(self) -> CategoricalDtype:
"""
The :class:`~pandas.api.types.CategoricalDtype` for this instance.
"""
return self._dtype
@property
def _ndarray_values(self) -> np.ndarray:
return self.codes
@property
def _constructor(self) -> Type["Categorical"]:
return Categorical
@classmethod
def _from_sequence(cls, scalars, dtype=None, copy=False):
return Categorical(scalars, dtype=dtype)
def _formatter(self, boxed=False):
# Defer to CategoricalFormatter's formatter.
return None
def copy(self) -> "Categorical":
"""
Copy constructor.
"""
return self._constructor(
values=self._codes.copy(), dtype=self.dtype, fastpath=True
)
def astype(self, dtype: Dtype, copy: bool = True) -> ArrayLike:
"""
Coerce this type to another dtype
Parameters
----------
dtype : numpy dtype or pandas type
copy : bool, default True
By default, astype always returns a newly allocated object.
If copy is set to False and dtype is categorical, the original
object is returned.
"""
if is_categorical_dtype(dtype):
dtype = cast(Union[str, CategoricalDtype], dtype)
# GH 10696/18593
dtype = self.dtype.update_dtype(dtype)
self = self.copy() if copy else self
if dtype == self.dtype:
return self
return self._set_dtype(dtype)
if is_extension_array_dtype(dtype):
return array(self, dtype=dtype, copy=copy) # type: ignore # GH 28770
if is_integer_dtype(dtype) and self.isna().any():
msg = "Cannot convert float NaN to integer"
raise ValueError(msg)
return np.array(self, dtype=dtype, copy=copy)
@cache_readonly
def size(self) -> int:
"""
return the len of myself
"""
return self._codes.size
@cache_readonly
def itemsize(self) -> int:
"""
return the size of a single category
"""
return self.categories.itemsize
def tolist(self) -> list:
"""
Return a list of the values.
These are each a scalar type, which is a Python scalar
(for str, int, float) or a pandas scalar
(for Timestamp/Timedelta/Interval/Period)
"""
return list(self)
to_list = tolist
@property
def base(self) -> None:
"""
compat, we are always our own object
"""
return None
@classmethod
def _from_inferred_categories(
cls, inferred_categories, inferred_codes, dtype, true_values=None
):
"""
Construct a Categorical from inferred values.
For inferred categories (`dtype` is None) the categories are sorted.
For explicit `dtype`, the `inferred_categories` are cast to the
appropriate type.
Parameters
----------
inferred_categories : Index
inferred_codes : Index
dtype : CategoricalDtype or 'category'
true_values : list, optional
If none are provided, the default ones are
"True", "TRUE", and "true."
Returns
-------
Categorical
"""
from pandas import Index, to_numeric, to_datetime, to_timedelta
cats = Index(inferred_categories)
known_categories = (
isinstance(dtype, CategoricalDtype) and dtype.categories is not None
)
if known_categories:
# Convert to a specialized type with `dtype` if specified.
if dtype.categories.is_numeric():
cats = to_numeric(inferred_categories, errors="coerce")
elif is_datetime64_dtype(dtype.categories):
cats = to_datetime(inferred_categories, errors="coerce")
elif is_timedelta64_dtype(dtype.categories):
cats = to_timedelta(inferred_categories, errors="coerce")
elif dtype.categories.is_boolean():
if true_values is None:
true_values = ["True", "TRUE", "true"]
cats = cats.isin(true_values)
if known_categories:
# Recode from observation order to dtype.categories order.
categories = dtype.categories
codes = _recode_for_categories(inferred_codes, cats, categories)
elif not cats.is_monotonic_increasing:
# Sort categories and recode for unknown categories.
unsorted = cats.copy()
categories = cats.sort_values()
codes = _recode_for_categories(inferred_codes, unsorted, categories)
dtype = CategoricalDtype(categories, ordered=False)
else:
dtype = CategoricalDtype(cats, ordered=False)
codes = inferred_codes
return cls(codes, dtype=dtype, fastpath=True)
@classmethod
def from_codes(cls, codes, categories=None, ordered=None, dtype=None):
"""
Make a Categorical type from codes and categories or dtype.
This constructor is useful if you already have codes and
categories/dtype and so do not need the (computation intensive)
factorization step, which is usually done on the constructor.
If your data does not follow this convention, please use the normal
constructor.
Parameters
----------
codes : array-like of int
An integer array, where each integer points to a category in
categories or dtype.categories, or else is -1 for NaN.
categories : index-like, optional
The categories for the categorical. Items need to be unique.
If the categories are not given here, then they must be provided
in `dtype`.
ordered : bool, optional
Whether or not this categorical is treated as an ordered
categorical. If not given here or in `dtype`, the resulting
categorical will be unordered.
dtype : CategoricalDtype or "category", optional
If :class:`CategoricalDtype`, cannot be used together with
`categories` or `ordered`.
.. versionadded:: 0.24.0
When `dtype` is provided, neither `categories` nor `ordered`
should be provided.
Returns
-------
Categorical
Examples
--------
>>> dtype = pd.CategoricalDtype(['a', 'b'], ordered=True)
>>> pd.Categorical.from_codes(codes=[0, 1, 0, 1], dtype=dtype)
[a, b, a, b]
Categories (2, object): [a < b]
"""
dtype = CategoricalDtype._from_values_or_dtype(
categories=categories, ordered=ordered, dtype=dtype
)
if dtype.categories is None:
msg = (
"The categories must be provided in 'categories' or "
"'dtype'. Both were None."
)
raise ValueError(msg)
codes = np.asarray(codes) # #21767
if len(codes) and not is_integer_dtype(codes):
msg = "codes need to be array-like integers"
if is_float_dtype(codes):
icodes = codes.astype("i8")
if (icodes == codes).all():
msg = None
codes = icodes
warn(
(
"float codes will be disallowed in the future and "
"raise a ValueError"
),
FutureWarning,
stacklevel=2,
)
if msg:
raise ValueError(msg)
if len(codes) and (codes.max() >= len(dtype.categories) or codes.min() < -1):
raise ValueError("codes need to be between -1 and len(categories)-1")
return cls(codes, dtype=dtype, fastpath=True)
def _get_codes(self):
"""
Get the codes.
Returns
-------
codes : integer array view
A non writable view of the `codes` array.
"""
v = self._codes.view()
v.flags.writeable = False
return v
def _set_codes(self, codes):
"""
Not settable by the user directly
"""
raise ValueError("cannot set Categorical codes directly")
codes = property(fget=_get_codes, fset=_set_codes, doc=_codes_doc)
def _set_categories(self, categories, fastpath=False):
"""
Sets new categories inplace
Parameters
----------
fastpath : bool, default False
Don't perform validation of the categories for uniqueness or nulls
Examples
--------
>>> c = pd.Categorical(['a', 'b'])
>>> c
[a, b]
Categories (2, object): [a, b]
>>> c._set_categories(pd.Index(['a', 'c']))
>>> c
[a, c]
Categories (2, object): [a, c]
"""
if fastpath:
new_dtype = CategoricalDtype._from_fastpath(categories, self.ordered)
else:
new_dtype = CategoricalDtype(categories, ordered=self.ordered)
if (
not fastpath
and self.dtype.categories is not None
and len(new_dtype.categories) != len(self.dtype.categories)
):
raise ValueError(
"new categories need to have the same number of "
"items than the old categories!"
)
self._dtype = new_dtype
def _set_dtype(self, dtype: CategoricalDtype) -> "Categorical":
"""
Internal method for directly updating the CategoricalDtype
Parameters
----------
dtype : CategoricalDtype
Notes
-----
We don't do any validation here. It's assumed that the dtype is
a (valid) instance of `CategoricalDtype`.
"""
codes = _recode_for_categories(self.codes, self.categories, dtype.categories)
return type(self)(codes, dtype=dtype, fastpath=True)
def set_ordered(self, value, inplace=False):
"""
Set the ordered attribute to the boolean value.
Parameters
----------
value : bool
Set whether this categorical is ordered (True) or not (False).
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to the value.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
new_dtype = CategoricalDtype(self.categories, ordered=value)
cat = self if inplace else self.copy()
cat._dtype = new_dtype
if not inplace:
return cat
def as_ordered(self, inplace=False):
"""
Set the Categorical to be ordered.
Parameters
----------
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to True.
Returns
-------
Categorical
Ordered Categorical.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
return self.set_ordered(True, inplace=inplace)
def as_unordered(self, inplace=False):
"""
Set the Categorical to be unordered.
Parameters
----------
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to False.
Returns
-------
Categorical
Unordered Categorical.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
return self.set_ordered(False, inplace=inplace)
def set_categories(self, new_categories, ordered=None, rename=False, inplace=False):
"""
Set the categories to the specified new_categories.
`new_categories` can include new categories (which will result in
unused categories) or remove old categories (which results in values
set to NaN). If `rename==True`, the categories will simple be renamed
(less or more items than in old categories will result in values set to
NaN or in unused categories respectively).
This method can be used to perform more than one action of adding,
removing, and reordering simultaneously and is therefore faster than
performing the individual steps via the more specialised methods.
On the other hand this methods does not do checks (e.g., whether the
old categories are included in the new categories on a reorder), which
can result in surprising changes, for example when using special string
dtypes on python3, which does not considers a S1 string equal to a
single char python string.
Parameters
----------
new_categories : Index-like
The categories in new order.
ordered : bool, default False
Whether or not the categorical is treated as a ordered categorical.
If not given, do not change the ordered information.
rename : bool, default False
Whether or not the new_categories should be considered as a rename
of the old categories or as reordered categories.
inplace : bool, default False
Whether or not to reorder the categories in-place or return a copy
of this categorical with reordered categories.
Returns
-------
Categorical with reordered categories or None if inplace.
Raises
------
ValueError
If new_categories does not validate as categories
See Also
--------
rename_categories
reorder_categories
add_categories
remove_categories
remove_unused_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if ordered is None:
ordered = self.dtype._ordered
new_dtype = CategoricalDtype(new_categories, ordered=ordered)
cat = self if inplace else self.copy()
if rename:
if cat.dtype.categories is not None and len(new_dtype.categories) < len(
cat.dtype.categories
):
# remove all _codes which are larger and set to -1/NaN
cat._codes[cat._codes >= len(new_dtype.categories)] = -1
else:
codes = _recode_for_categories(
cat.codes, cat.categories, new_dtype.categories
)
cat._codes = codes
cat._dtype = new_dtype
if not inplace:
return cat
def rename_categories(self, new_categories, inplace=False):
"""
Rename categories.
Parameters
----------
new_categories : list-like, dict-like or callable
New categories which will replace old categories.
* list-like: all items must be unique and the number of items in
the new categories must match the existing number of categories.
* dict-like: specifies a mapping from
old categories to new. Categories not contained in the mapping
are passed through and extra categories in the mapping are
ignored.
.. versionadded:: 0.21.0.
* callable : a callable that is called on all items in the old
categories and whose return values comprise the new categories.
.. versionadded:: 0.23.0.
inplace : bool, default False
Whether or not to rename the categories inplace or return a copy of
this categorical with renamed categories.
Returns
-------
cat : Categorical or None
With ``inplace=False``, the new categorical is returned.
With ``inplace=True``, there is no return value.
Raises
------
ValueError
If new categories are list-like and do not have the same number of
items than the current categories or do not validate as categories
See Also
--------
reorder_categories
add_categories
remove_categories
remove_unused_categories
set_categories
Examples
--------
>>> c = pd.Categorical(['a', 'a', 'b'])
>>> c.rename_categories([0, 1])
[0, 0, 1]
Categories (2, int64): [0, 1]
For dict-like ``new_categories``, extra keys are ignored and
categories not in the dictionary are passed through
>>> c.rename_categories({'a': 'A', 'c': 'C'})
[A, A, b]
Categories (2, object): [A, b]
You may also provide a callable to create the new categories
>>> c.rename_categories(lambda x: x.upper())
[A, A, B]
Categories (2, object): [A, B]
"""
inplace = validate_bool_kwarg(inplace, "inplace")
cat = self if inplace else self.copy()
if is_dict_like(new_categories):
cat.categories = [new_categories.get(item, item) for item in cat.categories]
elif callable(new_categories):
cat.categories = [new_categories(item) for item in cat.categories]
else:
cat.categories = new_categories
if not inplace:
return cat
def reorder_categories(self, new_categories, ordered=None, inplace=False):
"""
Reorder categories as specified in new_categories.
`new_categories` need to include all old categories and no new category
items.
Parameters
----------
new_categories : Index-like
The categories in new order.
ordered : bool, optional
Whether or not the categorical is treated as a ordered categorical.
If not given, do not change the ordered information.
inplace : bool, default False
Whether or not to reorder the categories inplace or return a copy of
this categorical with reordered categories.
Returns
-------
cat : Categorical with reordered categories or None if inplace.
Raises
------
ValueError
If the new categories do not contain all old category items or any
new ones
See Also
--------
rename_categories
add_categories
remove_categories
remove_unused_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if set(self.dtype.categories) != set(new_categories):
raise ValueError(
"items in new_categories are not the same as in old categories"
)
return self.set_categories(new_categories, ordered=ordered, inplace=inplace)
def add_categories(self, new_categories, inplace=False):
"""
Add new categories.
`new_categories` will be included at the last/highest place in the
categories and will be unused directly after this call.
Parameters
----------
new_categories : category or list-like of category
The new categories to be included.
inplace : bool, default False
Whether or not to add the categories inplace or return a copy of
this categorical with added categories.
Returns
-------
cat : Categorical with new categories added or None if inplace.
Raises
------
ValueError
If the new categories include old categories or do not validate as
categories
See Also
--------
rename_categories
reorder_categories
remove_categories
remove_unused_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not is_list_like(new_categories):
new_categories = [new_categories]
already_included = set(new_categories) & set(self.dtype.categories)
if len(already_included) != 0:
msg = (
"new categories must not include old categories: "
"{already_included!s}"
)
raise ValueError(msg.format(already_included=already_included))
new_categories = list(self.dtype.categories) + list(new_categories)
new_dtype = CategoricalDtype(new_categories, self.ordered)
cat = self if inplace else self.copy()
cat._dtype = new_dtype
cat._codes = coerce_indexer_dtype(cat._codes, new_dtype.categories)
if not inplace:
return cat
def remove_categories(self, removals, inplace=False):
"""
Remove the specified categories.
`removals` must be included in the old categories. Values which were in
the removed categories will be set to NaN
Parameters
----------
removals : category or list of categories
The categories which should be removed.
inplace : bool, default False
Whether or not to remove the categories inplace or return a copy of
this categorical with removed categories.
Returns
-------
cat : Categorical with removed categories or None if inplace.
Raises
------
ValueError
If the removals are not contained in the categories
See Also
--------
rename_categories
reorder_categories
add_categories
remove_unused_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not is_list_like(removals):
removals = [removals]
removal_set = set(removals)
not_included = removal_set - set(self.dtype.categories)
new_categories = [c for c in self.dtype.categories if c not in removal_set]
# GH 10156
if any(isna(removals)):
not_included = {x for x in not_included if notna(x)}
new_categories = [x for x in new_categories if notna(x)]
if len(not_included) != 0:
msg = "removals must all be in old categories: {not_included!s}"
raise ValueError(msg.format(not_included=not_included))
return self.set_categories(
new_categories, ordered=self.ordered, rename=False, inplace=inplace
)
def remove_unused_categories(self, inplace=False):
"""
Remove categories which are not used.
Parameters
----------
inplace : bool, default False
Whether or not to drop unused categories inplace or return a copy of
this categorical with unused categories dropped.
Returns
-------
cat : Categorical with unused categories dropped or None if inplace.
See Also
--------
rename_categories
reorder_categories
add_categories
remove_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
cat = self if inplace else self.copy()
idx, inv = np.unique(cat._codes, return_inverse=True)
if idx.size != 0 and idx[0] == -1: # na sentinel
idx, inv = idx[1:], inv - 1
new_categories = cat.dtype.categories.take(idx)
new_dtype = CategoricalDtype._from_fastpath(
new_categories, ordered=self.ordered
)
cat._dtype = new_dtype
cat._codes = coerce_indexer_dtype(inv, new_dtype.categories)
if not inplace:
return cat
def map(self, mapper):
"""
Map categories using input correspondence (dict, Series, or function).
Maps the categories to new categories. If the mapping correspondence is
one-to-one the result is a :class:`~pandas.Categorical` which has the
same order property as the original, otherwise a :class:`~pandas.Index`
is returned. NaN values are unaffected.
If a `dict` or :class:`~pandas.Series` is used any unmapped category is
mapped to `NaN`. Note that if this happens an :class:`~pandas.Index`
will be returned.
Parameters
----------
mapper : function, dict, or Series
Mapping correspondence.
Returns
-------
pandas.Categorical or pandas.Index
Mapped categorical.
See Also
--------
CategoricalIndex.map : Apply a mapping correspondence on a
:class:`~pandas.CategoricalIndex`.
Index.map : Apply a mapping correspondence on an
:class:`~pandas.Index`.
Series.map : Apply a mapping correspondence on a
:class:`~pandas.Series`.
Series.apply : Apply more complex functions on a
:class:`~pandas.Series`.
Examples
--------
>>> cat = pd.Categorical(['a', 'b', 'c'])
>>> cat
[a, b, c]
Categories (3, object): [a, b, c]
>>> cat.map(lambda x: x.upper())
[A, B, C]
Categories (3, object): [A, B, C]
>>> cat.map({'a': 'first', 'b': 'second', 'c': 'third'})
[first, second, third]
Categories (3, object): [first, second, third]
If the mapping is one-to-one the ordering of the categories is
preserved:
>>> cat = pd.Categorical(['a', 'b', 'c'], ordered=True)
>>> cat
[a, b, c]
Categories (3, object): [a < b < c]
>>> cat.map({'a': 3, 'b': 2, 'c': 1})
[3, 2, 1]
Categories (3, int64): [3 < 2 < 1]
If the mapping is not one-to-one an :class:`~pandas.Index` is returned:
>>> cat.map({'a': 'first', 'b': 'second', 'c': 'first'})
Index(['first', 'second', 'first'], dtype='object')
If a `dict` is used, all unmapped categories are mapped to `NaN` and
the result is an :class:`~pandas.Index`:
>>> cat.map({'a': 'first', 'b': 'second'})
Index(['first', 'second', nan], dtype='object')
"""
new_categories = self.categories.map(mapper)
try:
return self.from_codes(
self._codes.copy(), categories=new_categories, ordered=self.ordered
)
except ValueError:
# NA values are represented in self._codes with -1
# np.take causes NA values to take final element in new_categories
if np.any(self._codes == -1):
new_categories = new_categories.insert(len(new_categories), np.nan)
return np.take(new_categories, self._codes)
__eq__ = _cat_compare_op(operator.eq)
__ne__ = _cat_compare_op(operator.ne)
__lt__ = _cat_compare_op(operator.lt)
__gt__ = _cat_compare_op(operator.gt)
__le__ = _cat_compare_op(operator.le)
__ge__ = _cat_compare_op(operator.ge)
# for Series/ndarray like compat
@property
def shape(self):
"""
Shape of the Categorical.
For internal compatibility with numpy arrays.
Returns
-------
shape : tuple
"""
return tuple([len(self._codes)])
def shift(self, periods, fill_value=None):
"""
Shift Categorical by desired number of periods.
Parameters
----------
periods : int
Number of periods to move, can be positive or negative
fill_value : object, optional
The scalar value to use for newly introduced missing values.
.. versionadded:: 0.24.0
Returns
-------
shifted : Categorical
"""
# since categoricals always have ndim == 1, an axis parameter
# doesn't make any sense here.
codes = self.codes
if codes.ndim > 1:
raise NotImplementedError("Categorical with ndim > 1.")
if np.prod(codes.shape) and (periods != 0):
codes = np.roll(codes, ensure_platform_int(periods), axis=0)
if isna(fill_value):
fill_value = -1
elif fill_value in self.categories:
fill_value = self.categories.get_loc(fill_value)
else:
raise ValueError(
"'fill_value={}' is not present "
"in this Categorical's "
"categories".format(fill_value)
)
if periods > 0:
codes[:periods] = fill_value
else:
codes[periods:] = fill_value
return self.from_codes(codes, dtype=self.dtype)
def __array__(self, dtype=None):
"""
The numpy array interface.
Returns
-------
numpy.array
A numpy array of either the specified dtype or,
if dtype==None (default), the same dtype as
categorical.categories.dtype.
"""
ret = take_1d(self.categories.values, self._codes)
if dtype and not is_dtype_equal(dtype, self.categories.dtype):
return np.asarray(ret, dtype)
if is_extension_array_dtype(ret):
# When we're a Categorical[ExtensionArray], like Interval,
# we need to ensure __array__ get's all the way to an
# ndarray.
ret = np.asarray(ret)
return ret
def __array_ufunc__(self, ufunc, method, *inputs, **kwargs):
# for binary ops, use our custom dunder methods
result = ops.maybe_dispatch_ufunc_to_dunder_op(
self, ufunc, method, *inputs, **kwargs
)
if result is not NotImplemented:
return result
# for all other cases, raise for now (similarly as what happens in
# Series.__array_prepare__)
raise TypeError(
"Object with dtype {dtype} cannot perform "
"the numpy op {op}".format(dtype=self.dtype, op=ufunc.__name__)
)
def __setstate__(self, state):
"""Necessary for making this object picklable"""
if not isinstance(state, dict):
raise Exception("invalid pickle state")
# compat with pre 0.21.0 CategoricalDtype change
if "_dtype" not in state:
state["_dtype"] = CategoricalDtype(state["_categories"], state["_ordered"])
for k, v in state.items():
setattr(self, k, v)
@property
def T(self):
"""
Return transposed numpy array.
"""
return self
@property
def nbytes(self):
return self._codes.nbytes + self.dtype.categories.values.nbytes
def memory_usage(self, deep=False):
"""
Memory usage of my values
Parameters
----------
deep : bool
Introspect the data deeply, interrogate
`object` dtypes for system-level memory consumption
Returns
-------
bytes used
Notes
-----
Memory usage does not include memory consumed by elements that
are not components of the array if deep=False
See Also
--------
numpy.ndarray.nbytes
"""
return self._codes.nbytes + self.dtype.categories.memory_usage(deep=deep)
@Substitution(klass="Categorical")
@Appender(_shared_docs["searchsorted"])
def searchsorted(self, value, side="left", sorter=None):
# searchsorted is very performance sensitive. By converting codes
# to same dtype as self.codes, we get much faster performance.
if is_scalar(value):
codes = self.categories.get_loc(value)
codes = self.codes.dtype.type(codes)
else:
locs = [self.categories.get_loc(x) for x in value]
codes = np.array(locs, dtype=self.codes.dtype)
return self.codes.searchsorted(codes, side=side, sorter=sorter)
def isna(self):
"""
Detect missing values
Missing values (-1 in .codes) are detected.
Returns
-------
a boolean array of whether my values are null
See Also
--------
isna : Top-level isna.
isnull : Alias of isna.
Categorical.notna : Boolean inverse of Categorical.isna.
"""
ret = self._codes == -1
return ret
isnull = isna
def notna(self):
"""
Inverse of isna
Both missing values (-1 in .codes) and NA as a category are detected as
null.
Returns
-------
a boolean array of whether my values are not null
See Also
--------
notna : Top-level notna.
notnull : Alias of notna.
Categorical.isna : Boolean inverse of Categorical.notna.
"""
return ~self.isna()
notnull = notna
def put(self, *args, **kwargs):
"""
Replace specific elements in the Categorical with given values.
"""
raise NotImplementedError(("'put' is not yet implemented for Categorical"))
def dropna(self):
"""
Return the Categorical without null values.
Missing values (-1 in .codes) are detected.
Returns
-------
valid : Categorical
"""
result = self[self.notna()]
return result
def value_counts(self, dropna=True):
"""
Return a Series containing counts of each category.
Every category will have an entry, even those with a count of 0.
Parameters
----------
dropna : bool, default True
Don't include counts of NaN.
Returns
-------
counts : Series
See Also
--------
Series.value_counts
"""
from pandas import Series, CategoricalIndex
code, cat = self._codes, self.categories
ncat, mask = len(cat), 0 <= code
ix, clean = np.arange(ncat), mask.all()
if dropna or clean:
obs = code if clean else code[mask]
count = np.bincount(obs, minlength=ncat or 0)
else:
count = np.bincount(np.where(mask, code, ncat))
ix = np.append(ix, -1)
ix = self._constructor(ix, dtype=self.dtype, fastpath=True)
return Series(count, index=CategoricalIndex(ix), dtype="int64")
def get_values(self):
"""
Return the values.
.. deprecated:: 0.25.0
For internal compatibility with pandas formatting.
Returns
-------
numpy.array
A numpy array of the same dtype as categorical.categories.dtype or
Index if datetime / periods.
"""
warn(
"The 'get_values' method is deprecated and will be removed in a "
"future version",
FutureWarning,
stacklevel=2,
)
return self._internal_get_values()
def _internal_get_values(self):
# if we are a datetime and period index, return Index to keep metadata
if needs_i8_conversion(self.categories):
return self.categories.take(self._codes, fill_value=np.nan)
elif is_integer_dtype(self.categories) and -1 in self._codes:
return self.categories.astype("object").take(self._codes, fill_value=np.nan)
return np.array(self)
def check_for_ordered(self, op):
""" assert that we are ordered """
if not self.ordered:
raise TypeError(
"Categorical is not ordered for operation {op}\n"
"you can use .as_ordered() to change the "
"Categorical to an ordered one\n".format(op=op)
)
def _values_for_argsort(self):
return self._codes.copy()
def argsort(self, ascending=True, kind="quicksort", *args, **kwargs):
"""
Return the indices that would sort the Categorical.
.. versionchanged:: 0.25.0
Changed to sort missing values at the end.
Parameters
----------
ascending : bool, default True
Whether the indices should result in an ascending
or descending sort.
kind : {'quicksort', 'mergesort', 'heapsort'}, optional
Sorting algorithm.
*args, **kwargs:
passed through to :func:`numpy.argsort`.
Returns
-------
numpy.array
See Also
--------
numpy.ndarray.argsort
Notes
-----
While an ordering is applied to the category values, arg-sorting
in this context refers more to organizing and grouping together
based on matching category values. Thus, this function can be
called on an unordered Categorical instance unlike the functions
'Categorical.min' and 'Categorical.max'.
Examples
--------
>>> pd.Categorical(['b', 'b', 'a', 'c']).argsort()
array([2, 0, 1, 3])
>>> cat = pd.Categorical(['b', 'b', 'a', 'c'],
... categories=['c', 'b', 'a'],
... ordered=True)
>>> cat.argsort()
array([3, 0, 1, 2])
Missing values are placed at the end
>>> cat = pd.Categorical([2, None, 1])
>>> cat.argsort()
array([2, 0, 1])
"""
return super().argsort(ascending=ascending, kind=kind, *args, **kwargs)
def sort_values(self, inplace=False, ascending=True, na_position="last"):
"""
Sort the Categorical by category value returning a new
Categorical by default.
While an ordering is applied to the category values, sorting in this
context refers more to organizing and grouping together based on
matching category values. Thus, this function can be called on an
unordered Categorical instance unlike the functions 'Categorical.min'
and 'Categorical.max'.
Parameters
----------
inplace : bool, default False
Do operation in place.
ascending : bool, default True
Order ascending. Passing False orders descending. The
ordering parameter provides the method by which the
category values are organized.
na_position : {'first', 'last'} (optional, default='last')
'first' puts NaNs at the beginning
'last' puts NaNs at the end
Returns
-------
Categorical or None
See Also
--------
Categorical.sort
Series.sort_values
Examples
--------
>>> c = pd.Categorical([1, 2, 2, 1, 5])
>>> c
[1, 2, 2, 1, 5]
Categories (3, int64): [1, 2, 5]
>>> c.sort_values()
[1, 1, 2, 2, 5]
Categories (3, int64): [1, 2, 5]
>>> c.sort_values(ascending=False)
[5, 2, 2, 1, 1]
Categories (3, int64): [1, 2, 5]
Inplace sorting can be done as well:
>>> c.sort_values(inplace=True)
>>> c
[1, 1, 2, 2, 5]
Categories (3, int64): [1, 2, 5]
>>>
>>> c = pd.Categorical([1, 2, 2, 1, 5])
'sort_values' behaviour with NaNs. Note that 'na_position'
is independent of the 'ascending' parameter:
>>> c = pd.Categorical([np.nan, 2, 2, np.nan, 5])
>>> c
[NaN, 2.0, 2.0, NaN, 5.0]
Categories (2, int64): [2, 5]
>>> c.sort_values()
[2.0, 2.0, 5.0, NaN, NaN]
Categories (2, int64): [2, 5]
>>> c.sort_values(ascending=False)
[5.0, 2.0, 2.0, NaN, NaN]
Categories (2, int64): [2, 5]
>>> c.sort_values(na_position='first')
[NaN, NaN, 2.0, 2.0, 5.0]
Categories (2, int64): [2, 5]
>>> c.sort_values(ascending=False, na_position='first')
[NaN, NaN, 5.0, 2.0, 2.0]
Categories (2, int64): [2, 5]
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if na_position not in ["last", "first"]:
msg = "invalid na_position: {na_position!r}"
raise ValueError(msg.format(na_position=na_position))
sorted_idx = nargsort(self, ascending=ascending, na_position=na_position)
if inplace:
self._codes = self._codes[sorted_idx]
else:
return self._constructor(
values=self._codes[sorted_idx], dtype=self.dtype, fastpath=True
)
def _values_for_rank(self):
"""
For correctly ranking ordered categorical data. See GH#15420
Ordered categorical data should be ranked on the basis of
codes with -1 translated to NaN.
Returns
-------
numpy.array
"""
from pandas import Series
if self.ordered:
values = self.codes
mask = values == -1
if mask.any():
values = values.astype("float64")
values[mask] = np.nan
elif self.categories.is_numeric():
values = np.array(self)
else:
# reorder the categories (so rank can use the float codes)
# instead of passing an object array to rank
values = np.array(
self.rename_categories(Series(self.categories).rank().values)
)
return values
def ravel(self, order="C"):
"""
Return a flattened (numpy) array.
For internal compatibility with numpy arrays.
Returns
-------
numpy.array
"""
warn(
"Categorical.ravel will return a Categorical object instead "
"of an ndarray in a future version.",
FutureWarning,
stacklevel=2,
)
return np.array(self)
def view(self, dtype=None):
if dtype is not None:
raise NotImplementedError(dtype)
return self._constructor(values=self._codes, dtype=self.dtype, fastpath=True)
def to_dense(self):
"""
Return my 'dense' representation
For internal compatibility with numpy arrays.
Returns
-------
dense : array
"""
return np.asarray(self)
@deprecate_kwarg(old_arg_name="fill_value", new_arg_name="value")
def fillna(self, value=None, method=None, limit=None):
"""
Fill NA/NaN values using the specified method.
Parameters
----------
value : scalar, dict, Series
If a scalar value is passed it is used to fill all missing values.
Alternatively, a Series or dict can be used to fill in different
values for each index. The value should not be a list. The
value(s) passed should either be in the categories or should be
NaN.
method : {'backfill', 'bfill', 'pad', 'ffill', None}, default None
Method to use for filling holes in reindexed Series
pad / ffill: propagate last valid observation forward to next valid
backfill / bfill: use NEXT valid observation to fill gap
limit : int, default None
(Not implemented yet for Categorical!)
If method is specified, this is the maximum number of consecutive
NaN values to forward/backward fill. In other words, if there is
a gap with more than this number of consecutive NaNs, it will only
be partially filled. If method is not specified, this is the
maximum number of entries along the entire axis where NaNs will be
filled.
Returns
-------
filled : Categorical with NA/NaN filled
"""
value, method = validate_fillna_kwargs(
value, method, validate_scalar_dict_value=False
)
if value is None:
value = np.nan
if limit is not None:
raise NotImplementedError(
"specifying a limit for fillna has not been implemented yet"
)
codes = self._codes
# pad / bfill
if method is not None:
values = self.to_dense().reshape(-1, len(self))
values = interpolate_2d(values, method, 0, None, value).astype(
self.categories.dtype
)[0]
codes = _get_codes_for_values(values, self.categories)
else:
# If value is a dict or a Series (a dict value has already
# been converted to a Series)
if isinstance(value, ABCSeries):
if not value[~value.isin(self.categories)].isna().all():
raise ValueError("fill value must be in categories")
values_codes = _get_codes_for_values(value, self.categories)
indexer = np.where(codes == -1)
codes[indexer] = values_codes[indexer]
# If value is not a dict or Series it should be a scalar
elif is_hashable(value):
if not isna(value) and value not in self.categories:
raise ValueError("fill value must be in categories")
mask = codes == -1
if mask.any():
codes = codes.copy()
if isna(value):
codes[mask] = -1
else:
codes[mask] = self.categories.get_loc(value)
else:
raise TypeError(
'"value" parameter must be a scalar, dict '
"or Series, but you passed a "
'"{0}"'.format(type(value).__name__)
)
return self._constructor(codes, dtype=self.dtype, fastpath=True)
def take_nd(self, indexer, allow_fill=None, fill_value=None):
"""
Take elements from the Categorical.
Parameters
----------
indexer : sequence of int
The indices in `self` to take. The meaning of negative values in
`indexer` depends on the value of `allow_fill`.
allow_fill : bool, default None
How to handle negative values in `indexer`.
* False: negative values in `indices` indicate positional indices
from the right. This is similar to
:func:`numpy.take`.
* True: negative values in `indices` indicate missing values
(the default). These values are set to `fill_value`. Any other
other negative values raise a ``ValueError``.
.. versionchanged:: 0.23.0
Deprecated the default value of `allow_fill`. The deprecated
default is ``True``. In the future, this will change to
``False``.
fill_value : object
The value to use for `indices` that are missing (-1), when
``allow_fill=True``. This should be the category, i.e. a value
in ``self.categories``, not a code.
Returns
-------
Categorical
This Categorical will have the same categories and ordered as
`self`.
See Also
--------
Series.take : Similar method for Series.
numpy.ndarray.take : Similar method for NumPy arrays.
Examples
--------
>>> cat = pd.Categorical(['a', 'a', 'b'])
>>> cat
[a, a, b]
Categories (2, object): [a, b]
Specify ``allow_fill==False`` to have negative indices mean indexing
from the right.
>>> cat.take([0, -1, -2], allow_fill=False)
[a, b, a]
Categories (2, object): [a, b]
With ``allow_fill=True``, indices equal to ``-1`` mean "missing"
values that should be filled with the `fill_value`, which is
``np.nan`` by default.
>>> cat.take([0, -1, -1], allow_fill=True)
[a, NaN, NaN]
Categories (2, object): [a, b]
The fill value can be specified.
>>> cat.take([0, -1, -1], allow_fill=True, fill_value='a')
[a, a, a]
Categories (3, object): [a, b]
Specifying a fill value that's not in ``self.categories``
will raise a ``TypeError``.
"""
indexer = np.asarray(indexer, dtype=np.intp)
if allow_fill is None:
if (indexer < 0).any():
warn(_take_msg, FutureWarning, stacklevel=2)
allow_fill = True
dtype = self.dtype
if isna(fill_value):
fill_value = -1
elif allow_fill:
# convert user-provided `fill_value` to codes
if fill_value in self.categories:
fill_value = self.categories.get_loc(fill_value)
else:
msg = "'fill_value' ('{}') is not in this Categorical's categories."
raise TypeError(msg.format(fill_value))
codes = take(self._codes, indexer, allow_fill=allow_fill, fill_value=fill_value)
result = type(self).from_codes(codes, dtype=dtype)
return result
take = take_nd
def __len__(self) -> int:
"""
The length of this Categorical.
"""
return len(self._codes)
def __iter__(self):
"""
Returns an Iterator over the values of this Categorical.
"""
return iter(self._internal_get_values().tolist())
def __contains__(self, key):
"""
Returns True if `key` is in this Categorical.
"""
# if key is a NaN, check if any NaN is in self.
if is_scalar(key) and isna(key):
return self.isna().any()
return contains(self, key, container=self._codes)
def _tidy_repr(self, max_vals=10, footer=True):
""" a short repr displaying only max_vals and an optional (but default
footer)
"""
num = max_vals // 2
head = self[:num]._get_repr(length=False, footer=False)
tail = self[-(max_vals - num) :]._get_repr(length=False, footer=False)
result = "{head}, ..., {tail}".format(head=head[:-1], tail=tail[1:])
if footer:
result = "{result}\n{footer}".format(
result=result, footer=self._repr_footer()
)
return str(result)
def _repr_categories(self):
"""
return the base repr for the categories
"""
max_categories = (
10
if get_option("display.max_categories") == 0
else get_option("display.max_categories")
)
from pandas.io.formats import format as fmt
if len(self.categories) > max_categories:
num = max_categories // 2
head = fmt.format_array(self.categories[:num], None)
tail = fmt.format_array(self.categories[-num:], None)
category_strs = head + ["..."] + tail
else:
category_strs = fmt.format_array(self.categories, None)
# Strip all leading spaces, which format_array adds for columns...
category_strs = [x.strip() for x in category_strs]
return category_strs
def _repr_categories_info(self):
"""
Returns a string representation of the footer.
"""
category_strs = self._repr_categories()
dtype = str(self.categories.dtype)
levheader = "Categories ({length}, {dtype}): ".format(
length=len(self.categories), dtype=dtype
)
width, height = get_terminal_size()
max_width = get_option("display.width") or width
if console.in_ipython_frontend():
# 0 = no breaks
max_width = 0
levstring = ""
start = True
cur_col_len = len(levheader) # header
sep_len, sep = (3, " < ") if self.ordered else (2, ", ")
linesep = sep.rstrip() + "\n" # remove whitespace
for val in category_strs:
if max_width != 0 and cur_col_len + sep_len + len(val) > max_width:
levstring += linesep + (" " * (len(levheader) + 1))
cur_col_len = len(levheader) + 1 # header + a whitespace
elif not start:
levstring += sep
cur_col_len += len(val)
levstring += val
start = False
# replace to simple save space by
return levheader + "[" + levstring.replace(" < ... < ", " ... ") + "]"
def _repr_footer(self):
return "Length: {length}\n{info}".format(
length=len(self), info=self._repr_categories_info()
)
def _get_repr(self, length=True, na_rep="NaN", footer=True):
from pandas.io.formats import format as fmt
formatter = fmt.CategoricalFormatter(
self, length=length, na_rep=na_rep, footer=footer
)
result = formatter.to_string()
return str(result)
def __repr__(self) -> str:
"""
String representation.
"""
_maxlen = 10
if len(self._codes) > _maxlen:
result = self._tidy_repr(_maxlen)
elif len(self._codes) > 0:
result = self._get_repr(length=len(self) > _maxlen)
else:
msg = self._get_repr(length=False, footer=True).replace("\n", ", ")
result = "[], {repr_msg}".format(repr_msg=msg)
return result
def _maybe_coerce_indexer(self, indexer):
"""
return an indexer coerced to the codes dtype
"""
if isinstance(indexer, np.ndarray) and indexer.dtype.kind == "i":
indexer = indexer.astype(self._codes.dtype)
return indexer
def __getitem__(self, key):
"""
Return an item.
"""
if isinstance(key, (int, np.integer)):
i = self._codes[key]
if i == -1:
return np.nan
else:
return self.categories[i]
else:
return self._constructor(
values=self._codes[key], dtype=self.dtype, fastpath=True
)
def __setitem__(self, key, value):
"""
Item assignment.
Raises
------
ValueError
If (one or more) Value is not in categories or if a assigned
`Categorical` does not have the same categories
"""
value = extract_array(value, extract_numpy=True)
# require identical categories set
if isinstance(value, Categorical):
if not is_dtype_equal(self, value):
raise ValueError(
"Cannot set a Categorical with another, "
"without identical categories"
)
if not self.categories.equals(value.categories):
new_codes = _recode_for_categories(
value.codes, value.categories, self.categories
)
value = Categorical.from_codes(new_codes, dtype=self.dtype)
rvalue = value if is_list_like(value) else [value]
from pandas import Index
to_add = Index(rvalue).difference(self.categories)
# no assignments of values not in categories, but it's always ok to set
# something to np.nan
if len(to_add) and not isna(to_add).all():
raise ValueError(
"Cannot setitem on a Categorical with a new "
"category, set the categories first"
)
# set by position
if isinstance(key, (int, np.integer)):
pass
# tuple of indexers (dataframe)
elif isinstance(key, tuple):
# only allow 1 dimensional slicing, but can
# in a 2-d case be passd (slice(None),....)
if len(key) == 2:
if not com.is_null_slice(key[0]):
raise AssertionError("invalid slicing for a 1-ndim categorical")
key = key[1]
elif len(key) == 1:
key = key[0]
else:
raise AssertionError("invalid slicing for a 1-ndim categorical")
# slicing in Series or Categorical
elif isinstance(key, slice):
pass
# else: array of True/False in Series or Categorical
lindexer = self.categories.get_indexer(rvalue)
lindexer = self._maybe_coerce_indexer(lindexer)
self._codes[key] = lindexer
def _reverse_indexer(self):
"""
Compute the inverse of a categorical, returning
a dict of categories -> indexers.
*This is an internal function*
Returns
-------
dict of categories -> indexers
Examples
--------
>>> c = pd.Categorical(list('aabca'))
>>> c
[a, a, b, c, a]
Categories (3, object): [a, b, c]
>>> c.categories
Index(['a', 'b', 'c'], dtype='object')
>>> c.codes
array([0, 0, 1, 2, 0], dtype=int8)
>>> c._reverse_indexer()
{'a': array([0, 1, 4]), 'b': array([2]), 'c': array([3])}
"""
categories = self.categories
r, counts = libalgos.groupsort_indexer(
self.codes.astype("int64"), categories.size
)
counts = counts.cumsum()
result = (r[start:end] for start, end in zip(counts, counts[1:]))
result = dict(zip(categories, result))
return result
# reduction ops #
def _reduce(self, name, axis=0, **kwargs):
func = getattr(self, name, None)
if func is None:
msg = "Categorical cannot perform the operation {op}"
raise TypeError(msg.format(op=name))
return func(**kwargs)
def min(self, numeric_only=None, **kwargs):
"""
The minimum value of the object.
Only ordered `Categoricals` have a minimum!
Raises
------
TypeError
If the `Categorical` is not `ordered`.
Returns
-------
min : the minimum of this `Categorical`
"""
self.check_for_ordered("min")
if numeric_only:
good = self._codes != -1
pointer = self._codes[good].min(**kwargs)
else:
pointer = self._codes.min(**kwargs)
if pointer == -1:
return np.nan
else:
return self.categories[pointer]
def max(self, numeric_only=None, **kwargs):
"""
The maximum value of the object.
Only ordered `Categoricals` have a maximum!
Raises
------
TypeError
If the `Categorical` is not `ordered`.
Returns
-------
max : the maximum of this `Categorical`
"""
self.check_for_ordered("max")
if numeric_only:
good = self._codes != -1
pointer = self._codes[good].max(**kwargs)
else:
pointer = self._codes.max(**kwargs)
if pointer == -1:
return np.nan
else:
return self.categories[pointer]
def mode(self, dropna=True):
"""
Returns the mode(s) of the Categorical.
Always returns `Categorical` even if only one value.
Parameters
----------
dropna : bool, default True
Don't consider counts of NaN/NaT.
.. versionadded:: 0.24.0
Returns
-------
modes : `Categorical` (sorted)
"""
codes = self._codes
if dropna:
good = self._codes != -1
codes = self._codes[good]
codes = sorted(htable.mode_int64(ensure_int64(codes), dropna))
return self._constructor(values=codes, dtype=self.dtype, fastpath=True)
def unique(self):
"""
Return the ``Categorical`` which ``categories`` and ``codes`` are
unique. Unused categories are NOT returned.
- unordered category: values and categories are sorted by appearance
order.
- ordered category: values are sorted by appearance order, categories
keeps existing order.
Returns
-------
unique values : ``Categorical``
Examples
--------
An unordered Categorical will return categories in the
order of appearance.
>>> pd.Categorical(list('baabc'))
[b, a, c]
Categories (3, object): [b, a, c]
>>> pd.Categorical(list('baabc'), categories=list('abc'))
[b, a, c]
Categories (3, object): [b, a, c]
An ordered Categorical preserves the category ordering.
>>> pd.Categorical(list('baabc'),
... categories=list('abc'),
... ordered=True)
[b, a, c]
Categories (3, object): [a < b < c]
See Also
--------
unique
CategoricalIndex.unique
Series.unique
"""
# unlike np.unique, unique1d does not sort
unique_codes = unique1d(self.codes)
cat = self.copy()
# keep nan in codes
cat._codes = unique_codes
# exclude nan from indexer for categories
take_codes = unique_codes[unique_codes != -1]
if self.ordered:
take_codes = np.sort(take_codes)
return cat.set_categories(cat.categories.take(take_codes))
def _values_for_factorize(self):
codes = self.codes.astype("int64")
return codes, -1
@classmethod
def _from_factorized(cls, uniques, original):
return original._constructor(
original.categories.take(uniques), dtype=original.dtype
)
def equals(self, other):
"""
Returns True if categorical arrays are equal.
Parameters
----------
other : `Categorical`
Returns
-------
bool
"""
if self.is_dtype_equal(other):
if self.categories.equals(other.categories):
# fastpath to avoid re-coding
other_codes = other._codes
else:
other_codes = _recode_for_categories(
other.codes, other.categories, self.categories
)
return np.array_equal(self._codes, other_codes)
return False
def is_dtype_equal(self, other):
"""
Returns True if categoricals are the same dtype
same categories, and same ordered
Parameters
----------
other : Categorical
Returns
-------
bool
"""
try:
return hash(self.dtype) == hash(other.dtype)
except (AttributeError, TypeError):
return False
def describe(self):
"""
Describes this Categorical
Returns
-------
description: `DataFrame`
A dataframe with frequency and counts by category.
"""
counts = self.value_counts(dropna=False)
freqs = counts / float(counts.sum())
from pandas.core.reshape.concat import concat
result = concat([counts, freqs], axis=1)
result.columns = ["counts", "freqs"]
result.index.name = "categories"
return result
@Substitution(klass="Categorical")
@Appender(_extension_array_shared_docs["repeat"])
def repeat(self, repeats, axis=None):
nv.validate_repeat(tuple(), dict(axis=axis))
codes = self._codes.repeat(repeats)
return self._constructor(values=codes, dtype=self.dtype, fastpath=True)
# Implement the ExtensionArray interface
@property
def _can_hold_na(self):
return True
@classmethod
def _concat_same_type(self, to_concat):
from pandas.core.dtypes.concat import concat_categorical
return concat_categorical(to_concat)
def isin(self, values):
"""
Check whether `values` are contained in Categorical.
Return a boolean NumPy Array showing whether each element in
the Categorical matches an element in the passed sequence of
`values` exactly.
Parameters
----------
values : set or list-like
The sequence of values to test. Passing in a single string will
raise a ``TypeError``. Instead, turn a single string into a
list of one element.
Returns
-------
isin : numpy.ndarray (bool dtype)
Raises
------
TypeError
* If `values` is not a set or list-like
See Also
--------
pandas.Series.isin : Equivalent method on Series.
Examples
--------
>>> s = pd.Categorical(['lama', 'cow', 'lama', 'beetle', 'lama',
... 'hippo'])
>>> s.isin(['cow', 'lama'])
array([ True, True, True, False, True, False])
Passing a single string as ``s.isin('lama')`` will raise an error. Use
a list of one element instead:
>>> s.isin(['lama'])
array([ True, False, True, False, True, False])
"""
if not is_list_like(values):
raise TypeError(
"only list-like objects are allowed to be passed"
" to isin(), you passed a [{values_type}]".format(
values_type=type(values).__name__
)
)
values = sanitize_array(values, None, None)
null_mask = np.asarray(isna(values))
code_values = self.categories.get_indexer(values)
code_values = code_values[null_mask | (code_values >= 0)]
return algorithms.isin(self.codes, code_values)
# The Series.cat accessor
@delegate_names(
delegate=Categorical, accessors=["categories", "ordered"], typ="property"
)
@delegate_names(
delegate=Categorical,
accessors=[
"rename_categories",
"reorder_categories",
"add_categories",
"remove_categories",
"remove_unused_categories",
"set_categories",
"as_ordered",
"as_unordered",
],
typ="method",
)
class CategoricalAccessor(PandasDelegate, PandasObject, NoNewAttributesMixin):
"""
Accessor object for categorical properties of the Series values.
Be aware that assigning to `categories` is a inplace operation, while all
methods return new categorical data per default (but can be called with
`inplace=True`).
Parameters
----------
data : Series or CategoricalIndex
Examples
--------
>>> s.cat.categories
>>> s.cat.categories = list('abc')
>>> s.cat.rename_categories(list('cab'))
>>> s.cat.reorder_categories(list('cab'))
>>> s.cat.add_categories(['d','e'])
>>> s.cat.remove_categories(['d'])
>>> s.cat.remove_unused_categories()
>>> s.cat.set_categories(list('abcde'))
>>> s.cat.as_ordered()
>>> s.cat.as_unordered()
"""
_deprecations = PandasObject._deprecations | frozenset(
["categorical", "index", "name"]
)
def __init__(self, data):
self._validate(data)
self._parent = data.values
self._index = data.index
self._name = data.name
self._freeze()
@staticmethod
def _validate(data):
if not is_categorical_dtype(data.dtype):
raise AttributeError("Can only use .cat accessor with a 'category' dtype")
def _delegate_property_get(self, name):
return getattr(self._parent, name)
def _delegate_property_set(self, name, new_values):
return setattr(self._parent, name, new_values)
@property
def codes(self):
"""
Return Series of codes as well as the index.
"""
from pandas import Series
return Series(self._parent.codes, index=self._index)
def _delegate_method(self, name, *args, **kwargs):
from pandas import Series
method = getattr(self._parent, name)
res = method(*args, **kwargs)
if res is not None:
return Series(res, index=self._index, name=self._name)
@property
def categorical(self):
# Note: Upon deprecation, `test_tab_completion_with_categorical` will
# need to be updated. `categorical` will need to be removed from
# `ok_for_cat`.
warn(
"`Series.cat.categorical` has been deprecated. Use the "
"attributes on 'Series.cat' directly instead.",
FutureWarning,
stacklevel=2,
)
return self._parent
@property
def name(self):
# Note: Upon deprecation, `test_tab_completion_with_categorical` will
# need to be updated. `name` will need to be removed from
# `ok_for_cat`.
warn(
"`Series.cat.name` has been deprecated. Use `Series.name` instead.",
FutureWarning,
stacklevel=2,
)
return self._name
@property
def index(self):
# Note: Upon deprecation, `test_tab_completion_with_categorical` will
# need to be updated. `index` will need to be removed from
# ok_for_cat`.
warn(
"`Series.cat.index` has been deprecated. Use `Series.index` instead.",
FutureWarning,
stacklevel=2,
)
return self._index
# utility routines
def _get_codes_for_values(values, categories):
"""
utility routine to turn values into codes given the specified categories
"""
dtype_equal = is_dtype_equal(values.dtype, categories.dtype)
if dtype_equal:
# To prevent erroneous dtype coercion in _get_data_algo, retrieve
# the underlying numpy array. gh-22702
values = getattr(values, "_ndarray_values", values)
categories = getattr(categories, "_ndarray_values", categories)
elif is_extension_array_dtype(categories.dtype) and is_object_dtype(values):
# Support inferring the correct extension dtype from an array of
# scalar objects. e.g.
# Categorical(array[Period, Period], categories=PeriodIndex(...))
cls = categories.dtype.construct_array_type()
values = try_cast_to_ea(cls, values)
if not isinstance(values, cls):
# exception raised in _from_sequence
values = ensure_object(values)
categories = ensure_object(categories)
else:
values = ensure_object(values)
categories = ensure_object(categories)
hash_klass, vals = _get_data_algo(values)
_, cats = _get_data_algo(categories)
t = hash_klass(len(cats))
t.map_locations(cats)
return coerce_indexer_dtype(t.lookup(vals), cats)
def _recode_for_categories(codes: np.ndarray, old_categories, new_categories):
"""
Convert a set of codes for to a new set of categories
Parameters
----------
codes : np.ndarray
old_categories, new_categories : Index
Returns
-------
new_codes : np.ndarray[np.int64]
Examples
--------
>>> old_cat = pd.Index(['b', 'a', 'c'])
>>> new_cat = pd.Index(['a', 'b'])
>>> codes = np.array([0, 1, 1, 2])
>>> _recode_for_categories(codes, old_cat, new_cat)
array([ 1, 0, 0, -1])
"""
if len(old_categories) == 0:
# All null anyway, so just retain the nulls
return codes.copy()
elif new_categories.equals(old_categories):
# Same categories, so no need to actually recode
return codes.copy()
indexer = coerce_indexer_dtype(
new_categories.get_indexer(old_categories), new_categories
)
new_codes = take_1d(indexer, codes.copy(), fill_value=-1)
return new_codes
def _convert_to_list_like(list_like):
if hasattr(list_like, "dtype"):
return list_like
if isinstance(list_like, list):
return list_like
if is_sequence(list_like) or isinstance(list_like, tuple) or is_iterator(list_like):
return list(list_like)
elif is_scalar(list_like):
return [list_like]
else:
# TODO: is this reached?
return [list_like]
def factorize_from_iterable(values):
"""
Factorize an input `values` into `categories` and `codes`. Preserves
categorical dtype in `categories`.
*This is an internal function*
Parameters
----------
values : list-like
Returns
-------
codes : ndarray
categories : Index
If `values` has a categorical dtype, then `categories` is
a CategoricalIndex keeping the categories and order of `values`.
"""
if not is_list_like(values):
raise TypeError("Input must be list-like")
if is_categorical_dtype(values):
values = extract_array(values)
# The Categorical we want to build has the same categories
# as values but its codes are by def [0, ..., len(n_categories) - 1]
cat_codes = np.arange(len(values.categories), dtype=values.codes.dtype)
categories = Categorical.from_codes(cat_codes, dtype=values.dtype)
codes = values.codes
else:
# The value of ordered is irrelevant since we don't use cat as such,
# but only the resulting categories, the order of which is independent
# from ordered. Set ordered to False as default. See GH #15457
cat = Categorical(values, ordered=False)
categories = cat.categories
codes = cat.codes
return codes, categories
def factorize_from_iterables(iterables):
"""
A higher-level wrapper over `factorize_from_iterable`.
*This is an internal function*
Parameters
----------
iterables : list-like of list-likes
Returns
-------
codes_list : list of ndarrays
categories_list : list of Indexes
Notes
-----
See `factorize_from_iterable` for more info.
"""
if len(iterables) == 0:
# For consistency, it should return a list of 2 lists.
return [[], []]
return map(list, zip(*(factorize_from_iterable(it) for it in iterables)))
import operator
from shutil import get_terminal_size
import textwrap
from typing import Type, Union, cast
from warnings import warn
import numpy as np
from pandas._config import get_option
from pandas._libs import algos as libalgos, hashtable as htable
from pandas.compat.numpy import function as nv
from pandas.util._decorators import (
Appender,
Substitution,
cache_readonly,
deprecate_kwarg,
)
from pandas.util._validators import validate_bool_kwarg, validate_fillna_kwargs
from pandas.core.dtypes.cast import coerce_indexer_dtype, maybe_infer_to_datetimelike
from pandas.core.dtypes.common import (
ensure_int64,
ensure_object,
ensure_platform_int,
is_categorical_dtype,
is_datetime64_dtype,
is_dict_like,
is_dtype_equal,
is_extension_array_dtype,
is_float_dtype,
is_integer_dtype,
is_iterator,
is_list_like,
is_object_dtype,
is_scalar,
is_sequence,
is_timedelta64_dtype,
needs_i8_conversion,
)
from pandas.core.dtypes.dtypes import CategoricalDtype
from pandas.core.dtypes.generic import ABCIndexClass, ABCSeries
from pandas.core.dtypes.inference import is_hashable
from pandas.core.dtypes.missing import isna, notna
from pandas._typing import ArrayLike, Dtype, Ordered
from pandas.core import ops
from pandas.core.accessor import PandasDelegate, delegate_names
import pandas.core.algorithms as algorithms
from pandas.core.algorithms import _get_data_algo, factorize, take, take_1d, unique1d
from pandas.core.base import NoNewAttributesMixin, PandasObject, _shared_docs
import pandas.core.common as com
from pandas.core.construction import array, extract_array, sanitize_array
from pandas.core.missing import interpolate_2d
from pandas.core.ops.common import unpack_zerodim_and_defer
from pandas.core.sorting import nargsort
from pandas.io.formats import console
from .base import ExtensionArray, _extension_array_shared_docs, try_cast_to_ea
_take_msg = textwrap.dedent(
"""\
Interpreting negative values in 'indexer' as missing values.
In the future, this will change to meaning positional indices
from the right.
Use 'allow_fill=True' to retain the previous behavior and silence this
warning.
Use 'allow_fill=False' to accept the new behavior."""
)
def _cat_compare_op(op):
opname = "__{op}__".format(op=op.__name__)
@unpack_zerodim_and_defer(opname)
def f(self, other):
# On python2, you can usually compare any type to any type, and
# Categoricals can be seen as a custom type, but having different
# results depending whether categories are the same or not is kind of
# insane, so be a bit stricter here and use the python3 idea of
# comparing only things of equal type.
if is_list_like(other) and len(other) != len(self):
# TODO: Could this fail if the categories are listlike objects?
raise ValueError("Lengths must match.")
if not self.ordered:
if opname in ["__lt__", "__gt__", "__le__", "__ge__"]:
raise TypeError(
"Unordered Categoricals can only compare equality or not"
)
if isinstance(other, Categorical):
# Two Categoricals can only be be compared if the categories are
# the same (maybe up to ordering, depending on ordered)
msg = "Categoricals can only be compared if 'categories' are the same."
if len(self.categories) != len(other.categories):
raise TypeError(msg + " Categories are different lengths")
elif self.ordered and not (self.categories == other.categories).all():
raise TypeError(msg)
elif not set(self.categories) == set(other.categories):
raise TypeError(msg)
if not (self.ordered == other.ordered):
raise TypeError(
"Categoricals can only be compared if 'ordered' is the same"
)
if not self.ordered and not self.categories.equals(other.categories):
# both unordered and different order
other_codes = _get_codes_for_values(other, self.categories)
else:
other_codes = other._codes
mask = (self._codes == -1) | (other_codes == -1)
f = getattr(self._codes, opname)
ret = f(other_codes)
if mask.any():
# In other series, the leads to False, so do that here too
ret[mask] = False
return ret
if is_scalar(other):
if other in self.categories:
i = self.categories.get_loc(other)
ret = getattr(self._codes, opname)(i)
# check for NaN in self
mask = self._codes == -1
ret[mask] = False
return ret
else:
if opname == "__eq__":
return np.repeat(False, len(self))
elif opname == "__ne__":
return np.repeat(True, len(self))
else:
msg = (
"Cannot compare a Categorical for op {op} with a "
"scalar, which is not a category."
)
raise TypeError(msg.format(op=opname))
else:
# allow categorical vs object dtype array comparisons for equality
# these are only positional comparisons
if opname in ["__eq__", "__ne__"]:
return getattr(np.array(self), opname)(np.array(other))
msg = (
"Cannot compare a Categorical for op {op} with type {typ}."
"\nIf you want to compare values, use 'np.asarray(cat) "
"<op> other'."
)
raise TypeError(msg.format(op=opname, typ=type(other)))
f.__name__ = opname
return f
def contains(cat, key, container):
"""
Helper for membership check for ``key`` in ``cat``.
This is a helper method for :method:`__contains__`
and :class:`CategoricalIndex.__contains__`.
Returns True if ``key`` is in ``cat.categories`` and the
location of ``key`` in ``categories`` is in ``container``.
Parameters
----------
cat : :class:`Categorical`or :class:`categoricalIndex`
key : a hashable object
The key to check membership for.
container : Container (e.g. list-like or mapping)
The container to check for membership in.
Returns
-------
is_in : bool
True if ``key`` is in ``self.categories`` and location of
``key`` in ``categories`` is in ``container``, else False.
Notes
-----
This method does not check for NaN values. Do that separately
before calling this method.
"""
hash(key)
# get location of key in categories.
# If a KeyError, the key isn't in categories, so logically
# can't be in container either.
try:
loc = cat.categories.get_loc(key)
except (KeyError, TypeError):
return False
# loc is the location of key in categories, but also the *value*
# for key in container. So, `key` may be in categories,
# but still not in `container`. Example ('b' in categories,
# but not in values):
# 'b' in Categorical(['a'], categories=['a', 'b']) # False
if is_scalar(loc):
return loc in container
else:
# if categories is an IntervalIndex, loc is an array.
return any(loc_ in container for loc_ in loc)
_codes_doc = """
The category codes of this categorical.
Level codes are an array if integer which are the positions of the real
values in the categories array.
There is not setter, use the other categorical methods and the normal item
setter to change values in the categorical.
"""
class Categorical(ExtensionArray, PandasObject):
"""
Represent a categorical variable in classic R / S-plus fashion.
`Categoricals` can only take on only a limited, and usually fixed, number
of possible values (`categories`). In contrast to statistical categorical
variables, a `Categorical` might have an order, but numerical operations
(additions, divisions, ...) are not possible.
All values of the `Categorical` are either in `categories` or `np.nan`.
Assigning values outside of `categories` will raise a `ValueError`. Order
is defined by the order of the `categories`, not lexical order of the
values.
Parameters
----------
values : list-like
The values of the categorical. If categories are given, values not in
categories will be replaced with NaN.
categories : Index-like (unique), optional
The unique categories for this categorical. If not given, the
categories are assumed to be the unique values of `values` (sorted, if
possible, otherwise in the order in which they appear).
ordered : bool, default False
Whether or not this categorical is treated as a ordered categorical.
If True, the resulting categorical will be ordered.
An ordered categorical respects, when sorted, the order of its
`categories` attribute (which in turn is the `categories` argument, if
provided).
dtype : CategoricalDtype
An instance of ``CategoricalDtype`` to use for this categorical
.. versionadded:: 0.21.0
Attributes
----------
categories : Index
The categories of this categorical
codes : ndarray
The codes (integer positions, which point to the categories) of this
categorical, read only.
ordered : bool
Whether or not this Categorical is ordered.
dtype : CategoricalDtype
The instance of ``CategoricalDtype`` storing the ``categories``
and ``ordered``.
.. versionadded:: 0.21.0
Methods
-------
from_codes
__array__
Raises
------
ValueError
If the categories do not validate.
TypeError
If an explicit ``ordered=True`` is given but no `categories` and the
`values` are not sortable.
See Also
--------
CategoricalDtype : Type for categorical data.
CategoricalIndex : An Index with an underlying ``Categorical``.
Notes
-----
See the `user guide
<http://pandas.pydata.org/pandas-docs/stable/user_guide/categorical.html>`_
for more.
Examples
--------
>>> pd.Categorical([1, 2, 3, 1, 2, 3])
[1, 2, 3, 1, 2, 3]
Categories (3, int64): [1, 2, 3]
>>> pd.Categorical(['a', 'b', 'c', 'a', 'b', 'c'])
[a, b, c, a, b, c]
Categories (3, object): [a, b, c]
Ordered `Categoricals` can be sorted according to the custom order
of the categories and can have a min and max value.
>>> c = pd.Categorical(['a', 'b', 'c', 'a', 'b', 'c'], ordered=True,
... categories=['c', 'b', 'a'])
>>> c
[a, b, c, a, b, c]
Categories (3, object): [c < b < a]
>>> c.min()
'c'
"""
# For comparisons, so that numpy uses our implementation if the compare
# ops, which raise
__array_priority__ = 1000
_dtype = CategoricalDtype(ordered=False)
# tolist is not actually deprecated, just suppressed in the __dir__
_deprecations = PandasObject._deprecations | frozenset(
["tolist", "itemsize", "get_values"]
)
_typ = "categorical"
def __init__(
self, values, categories=None, ordered=None, dtype=None, fastpath=False
):
dtype = CategoricalDtype._from_values_or_dtype(
values, categories, ordered, dtype
)
# At this point, dtype is always a CategoricalDtype, but
# we may have dtype.categories be None, and we need to
# infer categories in a factorization step further below
if fastpath:
self._codes = coerce_indexer_dtype(values, dtype.categories)
self._dtype = self._dtype.update_dtype(dtype)
return
# null_mask indicates missing values we want to exclude from inference.
# This means: only missing values in list-likes (not arrays/ndframes).
null_mask = np.array(False)
# sanitize input
if is_categorical_dtype(values):
if dtype.categories is None:
dtype = CategoricalDtype(values.categories, dtype._ordered)
elif not isinstance(values, (ABCIndexClass, ABCSeries)):
# sanitize_array coerces np.nan to a string under certain versions
# of numpy
values = maybe_infer_to_datetimelike(values, convert_dates=True)
if not isinstance(values, np.ndarray):
values = _convert_to_list_like(values)
# By convention, empty lists result in object dtype:
if len(values) == 0:
sanitize_dtype = "object"
else:
sanitize_dtype = None
null_mask = isna(values)
if null_mask.any():
values = [values[idx] for idx in np.where(~null_mask)[0]]
values = sanitize_array(values, None, dtype=sanitize_dtype)
if dtype.categories is None:
try:
codes, categories = factorize(values, sort=True)
except TypeError:
codes, categories = factorize(values, sort=False)
if dtype._ordered:
# raise, as we don't have a sortable data structure and so
# the user should give us one by specifying categories
raise TypeError(
"'values' is not ordered, please "
"explicitly specify the categories order "
"by passing in a categories argument."
)
except ValueError:
# FIXME
raise NotImplementedError(
"> 1 ndim Categorical are not supported at this time"
)
# we're inferring from values
dtype = CategoricalDtype(categories, dtype._ordered)
elif is_categorical_dtype(values):
old_codes = (
values._values.codes if isinstance(values, ABCSeries) else values.codes
)
codes = _recode_for_categories(
old_codes, values.dtype.categories, dtype.categories
)
else:
codes = _get_codes_for_values(values, dtype.categories)
if null_mask.any():
# Reinsert -1 placeholders for previously removed missing values
full_codes = -np.ones(null_mask.shape, dtype=codes.dtype)
full_codes[~null_mask] = codes
codes = full_codes
self._dtype = self._dtype.update_dtype(dtype)
self._codes = coerce_indexer_dtype(codes, dtype.categories)
@property
def categories(self):
"""
The categories of this categorical.
Setting assigns new values to each category (effectively a rename of
each individual category).
The assigned value has to be a list-like object. All items must be
unique and the number of items in the new categories must be the same
as the number of items in the old categories.
Assigning to `categories` is a inplace operation!
Raises
------
ValueError
If the new categories do not validate as categories or if the
number of new categories is unequal the number of old categories
See Also
--------
rename_categories
reorder_categories
add_categories
remove_categories
remove_unused_categories
set_categories
"""
return self.dtype.categories
@categories.setter
def categories(self, categories):
new_dtype = CategoricalDtype(categories, ordered=self.ordered)
if self.dtype.categories is not None and len(self.dtype.categories) != len(
new_dtype.categories
):
raise ValueError(
"new categories need to have the same number of "
"items as the old categories!"
)
self._dtype = new_dtype
@property
def ordered(self) -> Ordered:
"""
Whether the categories have an ordered relationship.
"""
return self.dtype._ordered
@property
def dtype(self) -> CategoricalDtype:
"""
The :class:`~pandas.api.types.CategoricalDtype` for this instance.
"""
return self._dtype
@property
def _ndarray_values(self) -> np.ndarray:
return self.codes
@property
def _constructor(self) -> Type["Categorical"]:
return Categorical
@classmethod
def _from_sequence(cls, scalars, dtype=None, copy=False):
return Categorical(scalars, dtype=dtype)
def _formatter(self, boxed=False):
# Defer to CategoricalFormatter's formatter.
return None
def copy(self) -> "Categorical":
"""
Copy constructor.
"""
return self._constructor(
values=self._codes.copy(), dtype=self.dtype, fastpath=True
)
def astype(self, dtype: Dtype, copy: bool = True) -> ArrayLike:
"""
Coerce this type to another dtype
Parameters
----------
dtype : numpy dtype or pandas type
copy : bool, default True
By default, astype always returns a newly allocated object.
If copy is set to False and dtype is categorical, the original
object is returned.
"""
if is_categorical_dtype(dtype):
dtype = cast(Union[str, CategoricalDtype], dtype)
# GH 10696/18593
dtype = self.dtype.update_dtype(dtype)
self = self.copy() if copy else self
if dtype == self.dtype:
return self
return self._set_dtype(dtype)
if is_extension_array_dtype(dtype):
return array(self, dtype=dtype, copy=copy) # type: ignore # GH 28770
if is_integer_dtype(dtype) and self.isna().any():
msg = "Cannot convert float NaN to integer"
raise ValueError(msg)
return np.array(self, dtype=dtype, copy=copy)
@cache_readonly
def size(self) -> int:
"""
return the len of myself
"""
return self._codes.size
@cache_readonly
def itemsize(self) -> int:
"""
return the size of a single category
"""
return self.categories.itemsize
def tolist(self) -> list:
"""
Return a list of the values.
These are each a scalar type, which is a Python scalar
(for str, int, float) or a pandas scalar
(for Timestamp/Timedelta/Interval/Period)
"""
return list(self)
to_list = tolist
@property
def base(self) -> None:
"""
compat, we are always our own object
"""
return None
@classmethod
def _from_inferred_categories(
cls, inferred_categories, inferred_codes, dtype, true_values=None
):
"""
Construct a Categorical from inferred values.
For inferred categories (`dtype` is None) the categories are sorted.
For explicit `dtype`, the `inferred_categories` are cast to the
appropriate type.
Parameters
----------
inferred_categories : Index
inferred_codes : Index
dtype : CategoricalDtype or 'category'
true_values : list, optional
If none are provided, the default ones are
"True", "TRUE", and "true."
Returns
-------
Categorical
"""
from pandas import Index, to_numeric, to_datetime, to_timedelta
cats = Index(inferred_categories)
known_categories = (
isinstance(dtype, CategoricalDtype) and dtype.categories is not None
)
if known_categories:
# Convert to a specialized type with `dtype` if specified.
if dtype.categories.is_numeric():
cats = to_numeric(inferred_categories, errors="coerce")
elif is_datetime64_dtype(dtype.categories):
cats = to_datetime(inferred_categories, errors="coerce")
elif is_timedelta64_dtype(dtype.categories):
cats = to_timedelta(inferred_categories, errors="coerce")
elif dtype.categories.is_boolean():
if true_values is None:
true_values = ["True", "TRUE", "true"]
cats = cats.isin(true_values)
if known_categories:
# Recode from observation order to dtype.categories order.
categories = dtype.categories
codes = _recode_for_categories(inferred_codes, cats, categories)
elif not cats.is_monotonic_increasing:
# Sort categories and recode for unknown categories.
unsorted = cats.copy()
categories = cats.sort_values()
codes = _recode_for_categories(inferred_codes, unsorted, categories)
dtype = CategoricalDtype(categories, ordered=False)
else:
dtype = CategoricalDtype(cats, ordered=False)
codes = inferred_codes
return cls(codes, dtype=dtype, fastpath=True)
@classmethod
def from_codes(cls, codes, categories=None, ordered=None, dtype=None):
"""
Make a Categorical type from codes and categories or dtype.
This constructor is useful if you already have codes and
categories/dtype and so do not need the (computation intensive)
factorization step, which is usually done on the constructor.
If your data does not follow this convention, please use the normal
constructor.
Parameters
----------
codes : array-like of int
An integer array, where each integer points to a category in
categories or dtype.categories, or else is -1 for NaN.
categories : index-like, optional
The categories for the categorical. Items need to be unique.
If the categories are not given here, then they must be provided
in `dtype`.
ordered : bool, optional
Whether or not this categorical is treated as an ordered
categorical. If not given here or in `dtype`, the resulting
categorical will be unordered.
dtype : CategoricalDtype or "category", optional
If :class:`CategoricalDtype`, cannot be used together with
`categories` or `ordered`.
.. versionadded:: 0.24.0
When `dtype` is provided, neither `categories` nor `ordered`
should be provided.
Returns
-------
Categorical
Examples
--------
>>> dtype = pd.CategoricalDtype(['a', 'b'], ordered=True)
>>> pd.Categorical.from_codes(codes=[0, 1, 0, 1], dtype=dtype)
[a, b, a, b]
Categories (2, object): [a < b]
"""
dtype = CategoricalDtype._from_values_or_dtype(
categories=categories, ordered=ordered, dtype=dtype
)
if dtype.categories is None:
msg = (
"The categories must be provided in 'categories' or "
"'dtype'. Both were None."
)
raise ValueError(msg)
codes = np.asarray(codes) # #21767
if len(codes) and not is_integer_dtype(codes):
msg = "codes need to be array-like integers"
if is_float_dtype(codes):
icodes = codes.astype("i8")
if (icodes == codes).all():
msg = None
codes = icodes
warn(
(
"float codes will be disallowed in the future and "
"raise a ValueError"
),
FutureWarning,
stacklevel=2,
)
if msg:
raise ValueError(msg)
if len(codes) and (codes.max() >= len(dtype.categories) or codes.min() < -1):
raise ValueError("codes need to be between -1 and len(categories)-1")
return cls(codes, dtype=dtype, fastpath=True)
def _get_codes(self):
"""
Get the codes.
Returns
-------
codes : integer array view
A non writable view of the `codes` array.
"""
v = self._codes.view()
v.flags.writeable = False
return v
def _set_codes(self, codes):
"""
Not settable by the user directly
"""
raise ValueError("cannot set Categorical codes directly")
codes = property(fget=_get_codes, fset=_set_codes, doc=_codes_doc)
def _set_categories(self, categories, fastpath=False):
"""
Sets new categories inplace
Parameters
----------
fastpath : bool, default False
Don't perform validation of the categories for uniqueness or nulls
Examples
--------
>>> c = pd.Categorical(['a', 'b'])
>>> c
[a, b]
Categories (2, object): [a, b]
>>> c._set_categories(pd.Index(['a', 'c']))
>>> c
[a, c]
Categories (2, object): [a, c]
"""
if fastpath:
new_dtype = CategoricalDtype._from_fastpath(categories, self.ordered)
else:
new_dtype = CategoricalDtype(categories, ordered=self.ordered)
if (
not fastpath
and self.dtype.categories is not None
and len(new_dtype.categories) != len(self.dtype.categories)
):
raise ValueError(
"new categories need to have the same number of "
"items than the old categories!"
)
self._dtype = new_dtype
def _set_dtype(self, dtype: CategoricalDtype) -> "Categorical":
"""
Internal method for directly updating the CategoricalDtype
Parameters
----------
dtype : CategoricalDtype
Notes
-----
We don't do any validation here. It's assumed that the dtype is
a (valid) instance of `CategoricalDtype`.
"""
codes = _recode_for_categories(self.codes, self.categories, dtype.categories)
return type(self)(codes, dtype=dtype, fastpath=True)
def set_ordered(self, value, inplace=False):
"""
Set the ordered attribute to the boolean value.
Parameters
----------
value : bool
Set whether this categorical is ordered (True) or not (False).
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to the value.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
new_dtype = CategoricalDtype(self.categories, ordered=value)
cat = self if inplace else self.copy()
cat._dtype = new_dtype
if not inplace:
return cat
def as_ordered(self, inplace=False):
"""
Set the Categorical to be ordered.
Parameters
----------
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to True.
Returns
-------
Categorical
Ordered Categorical.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
return self.set_ordered(True, inplace=inplace)
def as_unordered(self, inplace=False):
"""
Set the Categorical to be unordered.
Parameters
----------
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to False.
Returns
-------
Categorical
Unordered Categorical.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
return self.set_ordered(False, inplace=inplace)
def set_categories(self, new_categories, ordered=None, rename=False, inplace=False):
"""
Set the categories to the specified new_categories.
`new_categories` can include new categories (which will result in
unused categories) or remove old categories (which results in values
set to NaN). If `rename==True`, the categories will simple be renamed
(less or more items than in old categories will result in values set to
NaN or in unused categories respectively).
This method can be used to perform more than one action of adding,
removing, and reordering simultaneously and is therefore faster than
performing the individual steps via the more specialised methods.
On the other hand this methods does not do checks (e.g., whether the
old categories are included in the new categories on a reorder), which
can result in surprising changes, for example when using special string
dtypes on python3, which does not considers a S1 string equal to a
single char python string.
Parameters
----------
new_categories : Index-like
The categories in new order.
ordered : bool, default False
Whether or not the categorical is treated as a ordered categorical.
If not given, do not change the ordered information.
rename : bool, default False
Whether or not the new_categories should be considered as a rename
of the old categories or as reordered categories.
inplace : bool, default False
Whether or not to reorder the categories in-place or return a copy
of this categorical with reordered categories.
Returns
-------
Categorical with reordered categories or None if inplace.
Raises
------
ValueError
If new_categories does not validate as categories
See Also
--------
rename_categories
reorder_categories
add_categories
remove_categories
remove_unused_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if ordered is None:
ordered = self.dtype._ordered
new_dtype = CategoricalDtype(new_categories, ordered=ordered)
cat = self if inplace else self.copy()
if rename:
if cat.dtype.categories is not None and len(new_dtype.categories) < len(
cat.dtype.categories
):
# remove all _codes which are larger and set to -1/NaN
cat._codes[cat._codes >= len(new_dtype.categories)] = -1
else:
codes = _recode_for_categories(
cat.codes, cat.categories, new_dtype.categories
)
cat._codes = codes
cat._dtype = new_dtype
if not inplace:
return cat
def rename_categories(self, new_categories, inplace=False):
"""
Rename categories.
Parameters
----------
new_categories : list-like, dict-like or callable
New categories which will replace old categories.
* list-like: all items must be unique and the number of items in
the new categories must match the existing number of categories.
* dict-like: specifies a mapping from
old categories to new. Categories not contained in the mapping
are passed through and extra categories in the mapping are
ignored.
.. versionadded:: 0.21.0.
* callable : a callable that is called on all items in the old
categories and whose return values comprise the new categories.
.. versionadded:: 0.23.0.
inplace : bool, default False
Whether or not to rename the categories inplace or return a copy of
this categorical with renamed categories.
Returns
-------
cat : Categorical or None
With ``inplace=False``, the new categorical is returned.
With ``inplace=True``, there is no return value.
Raises
------
ValueError
If new categories are list-like and do not have the same number of
items than the current categories or do not validate as categories
See Also
--------
reorder_categories
add_categories
remove_categories
remove_unused_categories
set_categories
Examples
--------
>>> c = pd.Categorical(['a', 'a', 'b'])
>>> c.rename_categories([0, 1])
[0, 0, 1]
Categories (2, int64): [0, 1]
For dict-like ``new_categories``, extra keys are ignored and
categories not in the dictionary are passed through
>>> c.rename_categories({'a': 'A', 'c': 'C'})
[A, A, b]
Categories (2, object): [A, b]
You may also provide a callable to create the new categories
>>> c.rename_categories(lambda x: x.upper())
[A, A, B]
Categories (2, object): [A, B]
"""
inplace = validate_bool_kwarg(inplace, "inplace")
cat = self if inplace else self.copy()
if is_dict_like(new_categories):
cat.categories = [new_categories.get(item, item) for item in cat.categories]
elif callable(new_categories):
cat.categories = [new_categories(item) for item in cat.categories]
else:
cat.categories = new_categories
if not inplace:
return cat
def reorder_categories(self, new_categories, ordered=None, inplace=False):
"""
Reorder categories as specified in new_categories.
`new_categories` need to include all old categories and no new category
items.
Parameters
----------
new_categories : Index-like
The categories in new order.
ordered : bool, optional
Whether or not the categorical is treated as a ordered categorical.
If not given, do not change the ordered information.
inplace : bool, default False
Whether or not to reorder the categories inplace or return a copy of
this categorical with reordered categories.
Returns
-------
cat : Categorical with reordered categories or None if inplace.
Raises
------
ValueError
If the new categories do not contain all old category items or any
new ones
See Also
--------
rename_categories
add_categories
remove_categories
remove_unused_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if set(self.dtype.categories) != set(new_categories):
raise ValueError(
"items in new_categories are not the same as in old categories"
)
return self.set_categories(new_categories, ordered=ordered, inplace=inplace)
def add_categories(self, new_categories, inplace=False):
"""
Add new categories.
`new_categories` will be included at the last/highest place in the
categories and will be unused directly after this call.
Parameters
----------
new_categories : category or list-like of category
The new categories to be included.
inplace : bool, default False
Whether or not to add the categories inplace or return a copy of
this categorical with added categories.
Returns
-------
cat : Categorical with new categories added or None if inplace.
Raises
------
ValueError
If the new categories include old categories or do not validate as
categories
See Also
--------
rename_categories
reorder_categories
remove_categories
remove_unused_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not is_list_like(new_categories):
new_categories = [new_categories]
already_included = set(new_categories) & set(self.dtype.categories)
if len(already_included) != 0:
msg = (
"new categories must not include old categories: "
"{already_included!s}"
)
raise ValueError(msg.format(already_included=already_included))
new_categories = list(self.dtype.categories) + list(new_categories)
new_dtype = CategoricalDtype(new_categories, self.ordered)
cat = self if inplace else self.copy()
cat._dtype = new_dtype
cat._codes = coerce_indexer_dtype(cat._codes, new_dtype.categories)
if not inplace:
return cat
def remove_categories(self, removals, inplace=False):
"""
Remove the specified categories.
`removals` must be included in the old categories. Values which were in
the removed categories will be set to NaN
Parameters
----------
removals : category or list of categories
The categories which should be removed.
inplace : bool, default False
Whether or not to remove the categories inplace or return a copy of
this categorical with removed categories.
Returns
-------
cat : Categorical with removed categories or None if inplace.
Raises
------
ValueError
If the removals are not contained in the categories
See Also
--------
rename_categories
reorder_categories
add_categories
remove_unused_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not is_list_like(removals):
removals = [removals]
removal_set = set(removals)
not_included = removal_set - set(self.dtype.categories)
new_categories = [c for c in self.dtype.categories if c not in removal_set]
# GH 10156
if any(isna(removals)):
not_included = {x for x in not_included if notna(x)}
new_categories = [x for x in new_categories if notna(x)]
if len(not_included) != 0:
msg = "removals must all be in old categories: {not_included!s}"
raise ValueError(msg.format(not_included=not_included))
return self.set_categories(
new_categories, ordered=self.ordered, rename=False, inplace=inplace
)
def remove_unused_categories(self, inplace=False):
"""
Remove categories which are not used.
Parameters
----------
inplace : bool, default False
Whether or not to drop unused categories inplace or return a copy of
this categorical with unused categories dropped.
Returns
-------
cat : Categorical with unused categories dropped or None if inplace.
See Also
--------
rename_categories
reorder_categories
add_categories
remove_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
cat = self if inplace else self.copy()
idx, inv = np.unique(cat._codes, return_inverse=True)
if idx.size != 0 and idx[0] == -1: # na sentinel
idx, inv = idx[1:], inv - 1
new_categories = cat.dtype.categories.take(idx)
new_dtype = CategoricalDtype._from_fastpath(
new_categories, ordered=self.ordered
)
cat._dtype = new_dtype
cat._codes = coerce_indexer_dtype(inv, new_dtype.categories)
if not inplace:
return cat
def map(self, mapper):
"""
Map categories using input correspondence (dict, Series, or function).
Maps the categories to new categories. If the mapping correspondence is
one-to-one the result is a :class:`~pandas.Categorical` which has the
same order property as the original, otherwise a :class:`~pandas.Index`
is returned. NaN values are unaffected.
If a `dict` or :class:`~pandas.Series` is used any unmapped category is
mapped to `NaN`. Note that if this happens an :class:`~pandas.Index`
will be returned.
Parameters
----------
mapper : function, dict, or Series
Mapping correspondence.
Returns
-------
pandas.Categorical or pandas.Index
Mapped categorical.
See Also
--------
CategoricalIndex.map : Apply a mapping correspondence on a
:class:`~pandas.CategoricalIndex`.
Index.map : Apply a mapping correspondence on an
:class:`~pandas.Index`.
Series.map : Apply a mapping correspondence on a
:class:`~pandas.Series`.
Series.apply : Apply more complex functions on a
:class:`~pandas.Series`.
Examples
--------
>>> cat = pd.Categorical(['a', 'b', 'c'])
>>> cat
[a, b, c]
Categories (3, object): [a, b, c]
>>> cat.map(lambda x: x.upper())
[A, B, C]
Categories (3, object): [A, B, C]
>>> cat.map({'a': 'first', 'b': 'second', 'c': 'third'})
[first, second, third]
Categories (3, object): [first, second, third]
If the mapping is one-to-one the ordering of the categories is
preserved:
>>> cat = pd.Categorical(['a', 'b', 'c'], ordered=True)
>>> cat
[a, b, c]
Categories (3, object): [a < b < c]
>>> cat.map({'a': 3, 'b': 2, 'c': 1})
[3, 2, 1]
Categories (3, int64): [3 < 2 < 1]
If the mapping is not one-to-one an :class:`~pandas.Index` is returned:
>>> cat.map({'a': 'first', 'b': 'second', 'c': 'first'})
Index(['first', 'second', 'first'], dtype='object')
If a `dict` is used, all unmapped categories are mapped to `NaN` and
the result is an :class:`~pandas.Index`:
>>> cat.map({'a': 'first', 'b': 'second'})
Index(['first', 'second', nan], dtype='object')
"""
new_categories = self.categories.map(mapper)
try:
return self.from_codes(
self._codes.copy(), categories=new_categories, ordered=self.ordered
)
except ValueError:
# NA values are represented in self._codes with -1
# np.take causes NA values to take final element in new_categories
if np.any(self._codes == -1):
new_categories = new_categories.insert(len(new_categories), np.nan)
return np.take(new_categories, self._codes)
__eq__ = _cat_compare_op(operator.eq)
__ne__ = _cat_compare_op(operator.ne)
__lt__ = _cat_compare_op(operator.lt)
__gt__ = _cat_compare_op(operator.gt)
__le__ = _cat_compare_op(operator.le)
__ge__ = _cat_compare_op(operator.ge)
# for Series/ndarray like compat
@property
def shape(self):
"""
Shape of the Categorical.
For internal compatibility with numpy arrays.
Returns
-------
shape : tuple
"""
return tuple([len(self._codes)])
def shift(self, periods, fill_value=None):
"""
Shift Categorical by desired number of periods.
Parameters
----------
periods : int
Number of periods to move, can be positive or negative
fill_value : object, optional
The scalar value to use for newly introduced missing values.
.. versionadded:: 0.24.0
Returns
-------
shifted : Categorical
"""
# since categoricals always have ndim == 1, an axis parameter
# doesn't make any sense here.
codes = self.codes
if codes.ndim > 1:
raise NotImplementedError("Categorical with ndim > 1.")
if np.prod(codes.shape) and (periods != 0):
codes = np.roll(codes, ensure_platform_int(periods), axis=0)
if isna(fill_value):
fill_value = -1
elif fill_value in self.categories:
fill_value = self.categories.get_loc(fill_value)
else:
raise ValueError(
"'fill_value={}' is not present "
"in this Categorical's "
"categories".format(fill_value)
)
if periods > 0:
codes[:periods] = fill_value
else:
codes[periods:] = fill_value
return self.from_codes(codes, dtype=self.dtype)
def __array__(self, dtype=None):
"""
The numpy array interface.
Returns
-------
numpy.array
A numpy array of either the specified dtype or,
if dtype==None (default), the same dtype as
categorical.categories.dtype.
"""
ret = take_1d(self.categories.values, self._codes)
if dtype and not is_dtype_equal(dtype, self.categories.dtype):
return np.asarray(ret, dtype)
if is_extension_array_dtype(ret):
# When we're a Categorical[ExtensionArray], like Interval,
# we need to ensure __array__ get's all the way to an
# ndarray.
ret = np.asarray(ret)
return ret
def __array_ufunc__(self, ufunc, method, *inputs, **kwargs):
# for binary ops, use our custom dunder methods
result = ops.maybe_dispatch_ufunc_to_dunder_op(
self, ufunc, method, *inputs, **kwargs
)
if result is not NotImplemented:
return result
# for all other cases, raise for now (similarly as what happens in
# Series.__array_prepare__)
raise TypeError(
"Object with dtype {dtype} cannot perform "
"the numpy op {op}".format(dtype=self.dtype, op=ufunc.__name__)
)
def __setstate__(self, state):
"""Necessary for making this object picklable"""
if not isinstance(state, dict):
raise Exception("invalid pickle state")
# compat with pre 0.21.0 CategoricalDtype change
if "_dtype" not in state:
state["_dtype"] = CategoricalDtype(state["_categories"], state["_ordered"])
for k, v in state.items():
setattr(self, k, v)
@property
def T(self):
"""
Return transposed numpy array.
"""
return self
@property
def nbytes(self):
return self._codes.nbytes + self.dtype.categories.values.nbytes
def memory_usage(self, deep=False):
"""
Memory usage of my values
Parameters
----------
deep : bool
Introspect the data deeply, interrogate
`object` dtypes for system-level memory consumption
Returns
-------
bytes used
Notes
-----
Memory usage does not include memory consumed by elements that
are not components of the array if deep=False
See Also
--------
numpy.ndarray.nbytes
"""
return self._codes.nbytes + self.dtype.categories.memory_usage(deep=deep)
@Substitution(klass="Categorical")
@Appender(_shared_docs["searchsorted"])
def searchsorted(self, value, side="left", sorter=None):
# searchsorted is very performance sensitive. By converting codes
# to same dtype as self.codes, we get much faster performance.
if is_scalar(value):
codes = self.categories.get_loc(value)
codes = self.codes.dtype.type(codes)
else:
locs = [self.categories.get_loc(x) for x in value]
codes = np.array(locs, dtype=self.codes.dtype)
return self.codes.searchsorted(codes, side=side, sorter=sorter)
def isna(self):
"""
Detect missing values
Missing values (-1 in .codes) are detected.
Returns
-------
a boolean array of whether my values are null
See Also
--------
isna : Top-level isna.
isnull : Alias of isna.
Categorical.notna : Boolean inverse of Categorical.isna.
"""
ret = self._codes == -1
return ret
isnull = isna
def notna(self):
"""
Inverse of isna
Both missing values (-1 in .codes) and NA as a category are detected as
null.
Returns
-------
a boolean array of whether my values are not null
See Also
--------
notna : Top-level notna.
notnull : Alias of notna.
Categorical.isna : Boolean inverse of Categorical.notna.
"""
return ~self.isna()
notnull = notna
def put(self, *args, **kwargs):
"""
Replace specific elements in the Categorical with given values.
"""
raise NotImplementedError(("'put' is not yet implemented for Categorical"))
def dropna(self):
"""
Return the Categorical without null values.
Missing values (-1 in .codes) are detected.
Returns
-------
valid : Categorical
"""
result = self[self.notna()]
return result
def value_counts(self, dropna=True):
"""
Return a Series containing counts of each category.
Every category will have an entry, even those with a count of 0.
Parameters
----------
dropna : bool, default True
Don't include counts of NaN.
Returns
-------
counts : Series
See Also
--------
Series.value_counts
"""
from pandas import Series, CategoricalIndex
code, cat = self._codes, self.categories
ncat, mask = len(cat), 0 <= code
ix, clean = np.arange(ncat), mask.all()
if dropna or clean:
obs = code if clean else code[mask]
count = np.bincount(obs, minlength=ncat or 0)
else:
count = np.bincount(np.where(mask, code, ncat))
ix = np.append(ix, -1)
ix = self._constructor(ix, dtype=self.dtype, fastpath=True)
return Series(count, index=CategoricalIndex(ix), dtype="int64")
def get_values(self):
"""
Return the values.
.. deprecated:: 0.25.0
For internal compatibility with pandas formatting.
Returns
-------
numpy.array
A numpy array of the same dtype as categorical.categories.dtype or
Index if datetime / periods.
"""
warn(
"The 'get_values' method is deprecated and will be removed in a "
"future version",
FutureWarning,
stacklevel=2,
)
return self._internal_get_values()
def _internal_get_values(self):
# if we are a datetime and period index, return Index to keep metadata
if needs_i8_conversion(self.categories):
return self.categories.take(self._codes, fill_value=np.nan)
elif is_integer_dtype(self.categories) and -1 in self._codes:
return self.categories.astype("object").take(self._codes, fill_value=np.nan)
return np.array(self)
def check_for_ordered(self, op):
""" assert that we are ordered """
if not self.ordered:
raise TypeError(
"Categorical is not ordered for operation {op}\n"
"you can use .as_ordered() to change the "
"Categorical to an ordered one\n".format(op=op)
)
def _values_for_argsort(self):
return self._codes.copy()
def argsort(self, ascending=True, kind="quicksort", *args, **kwargs):
"""
Return the indices that would sort the Categorical.
.. versionchanged:: 0.25.0
Changed to sort missing values at the end.
Parameters
----------
ascending : bool, default True
Whether the indices should result in an ascending
or descending sort.
kind : {'quicksort', 'mergesort', 'heapsort'}, optional
Sorting algorithm.
*args, **kwargs:
passed through to :func:`numpy.argsort`.
Returns
-------
numpy.array
See Also
--------
numpy.ndarray.argsort
Notes
-----
While an ordering is applied to the category values, arg-sorting
in this context refers more to organizing and grouping together
based on matching category values. Thus, this function can be
called on an unordered Categorical instance unlike the functions
'Categorical.min' and 'Categorical.max'.
Examples
--------
>>> pd.Categorical(['b', 'b', 'a', 'c']).argsort()
array([2, 0, 1, 3])
>>> cat = pd.Categorical(['b', 'b', 'a', 'c'],
... categories=['c', 'b', 'a'],
... ordered=True)
>>> cat.argsort()
array([3, 0, 1, 2])
Missing values are placed at the end
>>> cat = pd.Categorical([2, None, 1])
>>> cat.argsort()
array([2, 0, 1])
"""
return super().argsort(ascending=ascending, kind=kind, *args, **kwargs)
def sort_values(self, inplace=False, ascending=True, na_position="last"):
"""
Sort the Categorical by category value returning a new
Categorical by default.
While an ordering is applied to the category values, sorting in this
context refers more to organizing and grouping together based on
matching category values. Thus, this function can be called on an
unordered Categorical instance unlike the functions 'Categorical.min'
and 'Categorical.max'.
Parameters
----------
inplace : bool, default False
Do operation in place.
ascending : bool, default True
Order ascending. Passing False orders descending. The
ordering parameter provides the method by which the
category values are organized.
na_position : {'first', 'last'} (optional, default='last')
'first' puts NaNs at the beginning
'last' puts NaNs at the end
Returns
-------
Categorical or None
See Also
--------
Categorical.sort
Series.sort_values
Examples
--------
>>> c = pd.Categorical([1, 2, 2, 1, 5])
>>> c
[1, 2, 2, 1, 5]
Categories (3, int64): [1, 2, 5]
>>> c.sort_values()
[1, 1, 2, 2, 5]
Categories (3, int64): [1, 2, 5]
>>> c.sort_values(ascending=False)
[5, 2, 2, 1, 1]
Categories (3, int64): [1, 2, 5]
Inplace sorting can be done as well:
>>> c.sort_values(inplace=True)
>>> c
[1, 1, 2, 2, 5]
Categories (3, int64): [1, 2, 5]
>>>
>>> c = pd.Categorical([1, 2, 2, 1, 5])
'sort_values' behaviour with NaNs. Note that 'na_position'
is independent of the 'ascending' parameter:
>>> c = pd.Categorical([np.nan, 2, 2, np.nan, 5])
>>> c
[NaN, 2.0, 2.0, NaN, 5.0]
Categories (2, int64): [2, 5]
>>> c.sort_values()
[2.0, 2.0, 5.0, NaN, NaN]
Categories (2, int64): [2, 5]
>>> c.sort_values(ascending=False)
[5.0, 2.0, 2.0, NaN, NaN]
Categories (2, int64): [2, 5]
>>> c.sort_values(na_position='first')
[NaN, NaN, 2.0, 2.0, 5.0]
Categories (2, int64): [2, 5]
>>> c.sort_values(ascending=False, na_position='first')
[NaN, NaN, 5.0, 2.0, 2.0]
Categories (2, int64): [2, 5]
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if na_position not in ["last", "first"]:
msg = "invalid na_position: {na_position!r}"
raise ValueError(msg.format(na_position=na_position))
sorted_idx = nargsort(self, ascending=ascending, na_position=na_position)
if inplace:
self._codes = self._codes[sorted_idx]
else:
return self._constructor(
values=self._codes[sorted_idx], dtype=self.dtype, fastpath=True
)
def _values_for_rank(self):
"""
For correctly ranking ordered categorical data. See GH#15420
Ordered categorical data should be ranked on the basis of
codes with -1 translated to NaN.
Returns
-------
numpy.array
"""
from pandas import Series
if self.ordered:
values = self.codes
mask = values == -1
if mask.any():
values = values.astype("float64")
values[mask] = np.nan
elif self.categories.is_numeric():
values = np.array(self)
else:
# reorder the categories (so rank can use the float codes)
# instead of passing an object array to rank
values = np.array(
self.rename_categories(Series(self.categories).rank().values)
)
return values
def ravel(self, order="C"):
"""
Return a flattened (numpy) array.
For internal compatibility with numpy arrays.
Returns
-------
numpy.array
"""
warn(
"Categorical.ravel will return a Categorical object instead "
"of an ndarray in a future version.",
FutureWarning,
stacklevel=2,
)
return np.array(self)
def view(self, dtype=None):
if dtype is not None:
raise NotImplementedError(dtype)
return self._constructor(values=self._codes, dtype=self.dtype, fastpath=True)
def to_dense(self):
"""
Return my 'dense' representation
For internal compatibility with numpy arrays.
Returns
-------
dense : array
"""
return np.asarray(self)
@deprecate_kwarg(old_arg_name="fill_value", new_arg_name="value")
def fillna(self, value=None, method=None, limit=None):
"""
Fill NA/NaN values using the specified method.
Parameters
----------
value : scalar, dict, Series
If a scalar value is passed it is used to fill all missing values.
Alternatively, a Series or dict can be used to fill in different
values for each index. The value should not be a list. The
value(s) passed should either be in the categories or should be
NaN.
method : {'backfill', 'bfill', 'pad', 'ffill', None}, default None
Method to use for filling holes in reindexed Series
pad / ffill: propagate last valid observation forward to next valid
backfill / bfill: use NEXT valid observation to fill gap
limit : int, default None
(Not implemented yet for Categorical!)
If method is specified, this is the maximum number of consecutive
NaN values to forward/backward fill. In other words, if there is
a gap with more than this number of consecutive NaNs, it will only
be partially filled. If method is not specified, this is the
maximum number of entries along the entire axis where NaNs will be
filled.
Returns
-------
filled : Categorical with NA/NaN filled
"""
value, method = validate_fillna_kwargs(
value, method, validate_scalar_dict_value=False
)
if value is None:
value = np.nan
if limit is not None:
raise NotImplementedError(
"specifying a limit for fillna has not been implemented yet"
)
codes = self._codes
# pad / bfill
if method is not None:
values = self.to_dense().reshape(-1, len(self))
values = interpolate_2d(values, method, 0, None, value).astype(
self.categories.dtype
)[0]
codes = _get_codes_for_values(values, self.categories)
else:
# If value is a dict or a Series (a dict value has already
# been converted to a Series)
if isinstance(value, ABCSeries):
if not value[~value.isin(self.categories)].isna().all():
raise ValueError("fill value must be in categories")
values_codes = _get_codes_for_values(value, self.categories)
indexer = np.where(codes == -1)
codes[indexer] = values_codes[indexer]
# If value is not a dict or Series it should be a scalar
elif is_hashable(value):
if not isna(value) and value not in self.categories:
raise ValueError("fill value must be in categories")
mask = codes == -1
if mask.any():
codes = codes.copy()
if isna(value):
codes[mask] = -1
else:
codes[mask] = self.categories.get_loc(value)
else:
raise TypeError(
'"value" parameter must be a scalar, dict '
"or Series, but you passed a "
'"{0}"'.format(type(value).__name__)
)
return self._constructor(codes, dtype=self.dtype, fastpath=True)
def take_nd(self, indexer, allow_fill=None, fill_value=None):
"""
Take elements from the Categorical.
Parameters
----------
indexer : sequence of int
The indices in `self` to take. The meaning of negative values in
`indexer` depends on the value of `allow_fill`.
allow_fill : bool, default None
How to handle negative values in `indexer`.
* False: negative values in `indices` indicate positional indices
from the right. This is similar to
:func:`numpy.take`.
* True: negative values in `indices` indicate missing values
(the default). These values are set to `fill_value`. Any other
other negative values raise a ``ValueError``.
.. versionchanged:: 0.23.0
Deprecated the default value of `allow_fill`. The deprecated
default is ``True``. In the future, this will change to
``False``.
fill_value : object
The value to use for `indices` that are missing (-1), when
``allow_fill=True``. This should be the category, i.e. a value
in ``self.categories``, not a code.
Returns
-------
Categorical
This Categorical will have the same categories and ordered as
`self`.
See Also
--------
Series.take : Similar method for Series.
numpy.ndarray.take : Similar method for NumPy arrays.
Examples
--------
>>> cat = pd.Categorical(['a', 'a', 'b'])
>>> cat
[a, a, b]
Categories (2, object): [a, b]
Specify ``allow_fill==False`` to have negative indices mean indexing
from the right.
>>> cat.take([0, -1, -2], allow_fill=False)
[a, b, a]
Categories (2, object): [a, b]
With ``allow_fill=True``, indices equal to ``-1`` mean "missing"
values that should be filled with the `fill_value`, which is
``np.nan`` by default.
>>> cat.take([0, -1, -1], allow_fill=True)
[a, NaN, NaN]
Categories (2, object): [a, b]
The fill value can be specified.
>>> cat.take([0, -1, -1], allow_fill=True, fill_value='a')
[a, a, a]
Categories (3, object): [a, b]
Specifying a fill value that's not in ``self.categories``
will raise a ``TypeError``.
"""
indexer = np.asarray(indexer, dtype=np.intp)
if allow_fill is None:
if (indexer < 0).any():
warn(_take_msg, FutureWarning, stacklevel=2)
allow_fill = True
dtype = self.dtype
if isna(fill_value):
fill_value = -1
elif allow_fill:
# convert user-provided `fill_value` to codes
if fill_value in self.categories:
fill_value = self.categories.get_loc(fill_value)
else:
msg = "'fill_value' ('{}') is not in this Categorical's categories."
raise TypeError(msg.format(fill_value))
codes = take(self._codes, indexer, allow_fill=allow_fill, fill_value=fill_value)
result = type(self).from_codes(codes, dtype=dtype)
return result
take = take_nd
def __len__(self) -> int:
"""
The length of this Categorical.
"""
return len(self._codes)
def __iter__(self):
"""
Returns an Iterator over the values of this Categorical.
"""
return iter(self._internal_get_values().tolist())
def __contains__(self, key):
"""
Returns True if `key` is in this Categorical.
"""
# if key is a NaN, check if any NaN is in self.
if is_scalar(key) and isna(key):
return self.isna().any()
return contains(self, key, container=self._codes)
def _tidy_repr(self, max_vals=10, footer=True):
""" a short repr displaying only max_vals and an optional (but default
footer)
"""
num = max_vals // 2
head = self[:num]._get_repr(length=False, footer=False)
tail = self[-(max_vals - num) :]._get_repr(length=False, footer=False)
result = "{head}, ..., {tail}".format(head=head[:-1], tail=tail[1:])
if footer:
result = "{result}\n{footer}".format(
result=result, footer=self._repr_footer()
)
return str(result)
def _repr_categories(self):
"""
return the base repr for the categories
"""
max_categories = (
10
if get_option("display.max_categories") == 0
else get_option("display.max_categories")
)
from pandas.io.formats import format as fmt
if len(self.categories) > max_categories:
num = max_categories // 2
head = fmt.format_array(self.categories[:num], None)
tail = fmt.format_array(self.categories[-num:], None)
category_strs = head + ["..."] + tail
else:
category_strs = fmt.format_array(self.categories, None)
# Strip all leading spaces, which format_array adds for columns...
category_strs = [x.strip() for x in category_strs]
return category_strs
def _repr_categories_info(self):
"""
Returns a string representation of the footer.
"""
category_strs = self._repr_categories()
dtype = str(self.categories.dtype)
levheader = "Categories ({length}, {dtype}): ".format(
length=len(self.categories), dtype=dtype
)
width, height = get_terminal_size()
max_width = get_option("display.width") or width
if console.in_ipython_frontend():
# 0 = no breaks
max_width = 0
levstring = ""
start = True
cur_col_len = len(levheader) # header
sep_len, sep = (3, " < ") if self.ordered else (2, ", ")
linesep = sep.rstrip() + "\n" # remove whitespace
for val in category_strs:
if max_width != 0 and cur_col_len + sep_len + len(val) > max_width:
levstring += linesep + (" " * (len(levheader) + 1))
cur_col_len = len(levheader) + 1 # header + a whitespace
elif not start:
levstring += sep
cur_col_len += len(val)
levstring += val
start = False
# replace to simple save space by
return levheader + "[" + levstring.replace(" < ... < ", " ... ") + "]"
def _repr_footer(self):
return "Length: {length}\n{info}".format(
length=len(self), info=self._repr_categories_info()
)
def _get_repr(self, length=True, na_rep="NaN", footer=True):
from pandas.io.formats import format as fmt
formatter = fmt.CategoricalFormatter(
self, length=length, na_rep=na_rep, footer=footer
)
result = formatter.to_string()
return str(result)
def __repr__(self) -> str:
"""
String representation.
"""
_maxlen = 10
if len(self._codes) > _maxlen:
result = self._tidy_repr(_maxlen)
elif len(self._codes) > 0:
result = self._get_repr(length=len(self) > _maxlen)
else:
msg = self._get_repr(length=False, footer=True).replace("\n", ", ")
result = "[], {repr_msg}".format(repr_msg=msg)
return result
def _maybe_coerce_indexer(self, indexer):
"""
return an indexer coerced to the codes dtype
"""
if isinstance(indexer, np.ndarray) and indexer.dtype.kind == "i":
indexer = indexer.astype(self._codes.dtype)
return indexer
def __getitem__(self, key):
"""
Return an item.
"""
if isinstance(key, (int, np.integer)):
i = self._codes[key]
if i == -1:
return np.nan
else:
return self.categories[i]
else:
return self._constructor(
values=self._codes[key], dtype=self.dtype, fastpath=True
)
def __setitem__(self, key, value):
"""
Item assignment.
Raises
------
ValueError
If (one or more) Value is not in categories or if a assigned
`Categorical` does not have the same categories
"""
value = extract_array(value, extract_numpy=True)
# require identical categories set
if isinstance(value, Categorical):
if not is_dtype_equal(self, value):
raise ValueError(
"Cannot set a Categorical with another, "
"without identical categories"
)
if not self.categories.equals(value.categories):
new_codes = _recode_for_categories(
value.codes, value.categories, self.categories
)
value = Categorical.from_codes(new_codes, dtype=self.dtype)
rvalue = value if is_list_like(value) else [value]
from pandas import Index
to_add = Index(rvalue).difference(self.categories)
# no assignments of values not in categories, but it's always ok to set
# something to np.nan
if len(to_add) and not isna(to_add).all():
raise ValueError(
"Cannot setitem on a Categorical with a new "
"category, set the categories first"
)
# set by position
if isinstance(key, (int, np.integer)):
pass
# tuple of indexers (dataframe)
elif isinstance(key, tuple):
# only allow 1 dimensional slicing, but can
# in a 2-d case be passd (slice(None),....)
if len(key) == 2:
if not com.is_null_slice(key[0]):
raise AssertionError("invalid slicing for a 1-ndim categorical")
key = key[1]
elif len(key) == 1:
key = key[0]
else:
raise AssertionError("invalid slicing for a 1-ndim categorical")
# slicing in Series or Categorical
elif isinstance(key, slice):
pass
# else: array of True/False in Series or Categorical
lindexer = self.categories.get_indexer(rvalue)
lindexer = self._maybe_coerce_indexer(lindexer)
self._codes[key] = lindexer
def _reverse_indexer(self):
"""
Compute the inverse of a categorical, returning
a dict of categories -> indexers.
*This is an internal function*
Returns
-------
dict of categories -> indexers
Examples
--------
>>> c = pd.Categorical(list('aabca'))
>>> c
[a, a, b, c, a]
Categories (3, object): [a, b, c]
>>> c.categories
Index(['a', 'b', 'c'], dtype='object')
>>> c.codes
array([0, 0, 1, 2, 0], dtype=int8)
>>> c._reverse_indexer()
{'a': array([0, 1, 4]), 'b': array([2]), 'c': array([3])}
"""
categories = self.categories
r, counts = libalgos.groupsort_indexer(
self.codes.astype("int64"), categories.size
)
counts = counts.cumsum()
result = (r[start:end] for start, end in zip(counts, counts[1:]))
result = dict(zip(categories, result))
return result
# reduction ops #
def _reduce(self, name, axis=0, **kwargs):
func = getattr(self, name, None)
if func is None:
msg = "Categorical cannot perform the operation {op}"
raise TypeError(msg.format(op=name))
return func(**kwargs)
def min(self, numeric_only=None, **kwargs):
"""
The minimum value of the object.
Only ordered `Categoricals` have a minimum!
Raises
------
TypeError
If the `Categorical` is not `ordered`.
Returns
-------
min : the minimum of this `Categorical`
"""
self.check_for_ordered("min")
if numeric_only:
good = self._codes != -1
pointer = self._codes[good].min(**kwargs)
else:
pointer = self._codes.min(**kwargs)
if pointer == -1:
return np.nan
else:
return self.categories[pointer]
def max(self, numeric_only=None, **kwargs):
"""
The maximum value of the object.
Only ordered `Categoricals` have a maximum!
Raises
------
TypeError
If the `Categorical` is not `ordered`.
Returns
-------
max : the maximum of this `Categorical`
"""
self.check_for_ordered("max")
if numeric_only:
good = self._codes != -1
pointer = self._codes[good].max(**kwargs)
else:
pointer = self._codes.max(**kwargs)
if pointer == -1:
return np.nan
else:
return self.categories[pointer]
def mode(self, dropna=True):
"""
Returns the mode(s) of the Categorical.
Always returns `Categorical` even if only one value.
Parameters
----------
dropna : bool, default True
Don't consider counts of NaN/NaT.
.. versionadded:: 0.24.0
Returns
-------
modes : `Categorical` (sorted)
"""
codes = self._codes
if dropna:
good = self._codes != -1
codes = self._codes[good]
codes = sorted(htable.mode_int64(ensure_int64(codes), dropna))
return self._constructor(values=codes, dtype=self.dtype, fastpath=True)
def unique(self):
"""
Return the ``Categorical`` which ``categories`` and ``codes`` are
unique. Unused categories are NOT returned.
- unordered category: values and categories are sorted by appearance
order.
- ordered category: values are sorted by appearance order, categories
keeps existing order.
Returns
-------
unique values : ``Categorical``
Examples
--------
An unordered Categorical will return categories in the
order of appearance.
>>> pd.Categorical(list('baabc'))
[b, a, c]
Categories (3, object): [b, a, c]
>>> pd.Categorical(list('baabc'), categories=list('abc'))
[b, a, c]
Categories (3, object): [b, a, c]
An ordered Categorical preserves the category ordering.
>>> pd.Categorical(list('baabc'),
... categories=list('abc'),
... ordered=True)
[b, a, c]
Categories (3, object): [a < b < c]
See Also
--------
unique
CategoricalIndex.unique
Series.unique
"""
# unlike np.unique, unique1d does not sort
unique_codes = unique1d(self.codes)
cat = self.copy()
# keep nan in codes
cat._codes = unique_codes
# exclude nan from indexer for categories
take_codes = unique_codes[unique_codes != -1]
if self.ordered:
take_codes = np.sort(take_codes)
return cat.set_categories(cat.categories.take(take_codes))
def _values_for_factorize(self):
codes = self.codes.astype("int64")
return codes, -1
@classmethod
def _from_factorized(cls, uniques, original):
return original._constructor(
original.categories.take(uniques), dtype=original.dtype
)
def equals(self, other):
"""
Returns True if categorical arrays are equal.
Parameters
----------
other : `Categorical`
Returns
-------
bool
"""
if self.is_dtype_equal(other):
if self.categories.equals(other.categories):
# fastpath to avoid re-coding
other_codes = other._codes
else:
other_codes = _recode_for_categories(
other.codes, other.categories, self.categories
)
return np.array_equal(self._codes, other_codes)
return False
def is_dtype_equal(self, other):
"""
Returns True if categoricals are the same dtype
same categories, and same ordered
Parameters
----------
other : Categorical
Returns
-------
bool
"""
try:
return hash(self.dtype) == hash(other.dtype)
except (AttributeError, TypeError):
return False
def describe(self):
"""
Describes this Categorical
Returns
-------
description: `DataFrame`
A dataframe with frequency and counts by category.
"""
counts = self.value_counts(dropna=False)
freqs = counts / float(counts.sum())
from pandas.core.reshape.concat import concat
result = concat([counts, freqs], axis=1)
result.columns = ["counts", "freqs"]
result.index.name = "categories"
return result
@Substitution(klass="Categorical")
@Appender(_extension_array_shared_docs["repeat"])
def repeat(self, repeats, axis=None):
nv.validate_repeat(tuple(), dict(axis=axis))
codes = self._codes.repeat(repeats)
return self._constructor(values=codes, dtype=self.dtype, fastpath=True)
# Implement the ExtensionArray interface
@property
def _can_hold_na(self):
return True
@classmethod
def _concat_same_type(self, to_concat):
from pandas.core.dtypes.concat import concat_categorical
return concat_categorical(to_concat)
def isin(self, values):
"""
Check whether `values` are contained in Categorical.
Return a boolean NumPy Array showing whether each element in
the Categorical matches an element in the passed sequence of
`values` exactly.
Parameters
----------
values : set or list-like
The sequence of values to test. Passing in a single string will
raise a ``TypeError``. Instead, turn a single string into a
list of one element.
Returns
-------
isin : numpy.ndarray (bool dtype)
Raises
------
TypeError
* If `values` is not a set or list-like
See Also
--------
pandas.Series.isin : Equivalent method on Series.
Examples
--------
>>> s = pd.Categorical(['lama', 'cow', 'lama', 'beetle', 'lama',
... 'hippo'])
>>> s.isin(['cow', 'lama'])
array([ True, True, True, False, True, False])
Passing a single string as ``s.isin('lama')`` will raise an error. Use
a list of one element instead:
>>> s.isin(['lama'])
array([ True, False, True, False, True, False])
"""
if not is_list_like(values):
raise TypeError(
"only list-like objects are allowed to be passed"
" to isin(), you passed a [{values_type}]".format(
values_type=type(values).__name__
)
)
values = sanitize_array(values, None, None)
null_mask = np.asarray(isna(values))
code_values = self.categories.get_indexer(values)
code_values = code_values[null_mask | (code_values >= 0)]
return algorithms.isin(self.codes, code_values)
def replace(self, to_replace, value, inplace: bool = False):
"""
Replaces all instances of one value with another
Parameters
----------
to_replace: object
The value to be replaced
value: object
The value to replace it with
inplace: bool
Whether the operation is done in-place
Returns
-------
None if inplace is True, otherwise the new Categorical after replacement
Examples
--------
>>> s = pd.Categorical([1, 2, 1, 3])
>>> s.replace(1, 3)
[3, 3, 2, 3]
Categories (2, int64): [2, 3]
"""
inplace = validate_bool_kwarg(inplace, "inplace")
cat = self if inplace else self.copy()
if to_replace in cat.categories:
if isna(value):
cat.remove_categories(to_replace, inplace=True)
else:
categories = cat.categories.tolist()
index = categories.index(to_replace)
if value in cat.categories:
value_index = categories.index(value)
cat._codes[cat._codes == index] = value_index
cat.remove_categories(to_replace, inplace=True)
else:
categories[index] = value
cat.rename_categories(categories, inplace=True)
if not inplace:
return cat
# The Series.cat accessor
@delegate_names(
delegate=Categorical, accessors=["categories", "ordered"], typ="property"
)
@delegate_names(
delegate=Categorical,
accessors=[
"rename_categories",
"reorder_categories",
"add_categories",
"remove_categories",
"remove_unused_categories",
"set_categories",
"as_ordered",
"as_unordered",
],
typ="method",
)
class CategoricalAccessor(PandasDelegate, PandasObject, NoNewAttributesMixin):
"""
Accessor object for categorical properties of the Series values.
Be aware that assigning to `categories` is a inplace operation, while all
methods return new categorical data per default (but can be called with
`inplace=True`).
Parameters
----------
data : Series or CategoricalIndex
Examples
--------
>>> s.cat.categories
>>> s.cat.categories = list('abc')
>>> s.cat.rename_categories(list('cab'))
>>> s.cat.reorder_categories(list('cab'))
>>> s.cat.add_categories(['d','e'])
>>> s.cat.remove_categories(['d'])
>>> s.cat.remove_unused_categories()
>>> s.cat.set_categories(list('abcde'))
>>> s.cat.as_ordered()
>>> s.cat.as_unordered()
"""
_deprecations = PandasObject._deprecations | frozenset(
["categorical", "index", "name"]
)
def __init__(self, data):
self._validate(data)
self._parent = data.values
self._index = data.index
self._name = data.name
self._freeze()
@staticmethod
def _validate(data):
if not is_categorical_dtype(data.dtype):
raise AttributeError("Can only use .cat accessor with a 'category' dtype")
def _delegate_property_get(self, name):
return getattr(self._parent, name)
def _delegate_property_set(self, name, new_values):
return setattr(self._parent, name, new_values)
@property
def codes(self):
"""
Return Series of codes as well as the index.
"""
from pandas import Series
return Series(self._parent.codes, index=self._index)
def _delegate_method(self, name, *args, **kwargs):
from pandas import Series
method = getattr(self._parent, name)
res = method(*args, **kwargs)
if res is not None:
return Series(res, index=self._index, name=self._name)
@property
def categorical(self):
# Note: Upon deprecation, `test_tab_completion_with_categorical` will
# need to be updated. `categorical` will need to be removed from
# `ok_for_cat`.
warn(
"`Series.cat.categorical` has been deprecated. Use the "
"attributes on 'Series.cat' directly instead.",
FutureWarning,
stacklevel=2,
)
return self._parent
@property
def name(self):
# Note: Upon deprecation, `test_tab_completion_with_categorical` will
# need to be updated. `name` will need to be removed from
# `ok_for_cat`.
warn(
"`Series.cat.name` has been deprecated. Use `Series.name` instead.",
FutureWarning,
stacklevel=2,
)
return self._name
@property
def index(self):
# Note: Upon deprecation, `test_tab_completion_with_categorical` will
# need to be updated. `index` will need to be removed from
# ok_for_cat`.
warn(
"`Series.cat.index` has been deprecated. Use `Series.index` instead.",
FutureWarning,
stacklevel=2,
)
return self._index
# utility routines
def _get_codes_for_values(values, categories):
"""
utility routine to turn values into codes given the specified categories
"""
dtype_equal = is_dtype_equal(values.dtype, categories.dtype)
if dtype_equal:
# To prevent erroneous dtype coercion in _get_data_algo, retrieve
# the underlying numpy array. gh-22702
values = getattr(values, "_ndarray_values", values)
categories = getattr(categories, "_ndarray_values", categories)
elif is_extension_array_dtype(categories.dtype) and is_object_dtype(values):
# Support inferring the correct extension dtype from an array of
# scalar objects. e.g.
# Categorical(array[Period, Period], categories=PeriodIndex(...))
cls = categories.dtype.construct_array_type()
values = try_cast_to_ea(cls, values)
if not isinstance(values, cls):
# exception raised in _from_sequence
values = ensure_object(values)
categories = ensure_object(categories)
else:
values = ensure_object(values)
categories = ensure_object(categories)
hash_klass, vals = _get_data_algo(values)
_, cats = _get_data_algo(categories)
t = hash_klass(len(cats))
t.map_locations(cats)
return coerce_indexer_dtype(t.lookup(vals), cats)
def _recode_for_categories(codes: np.ndarray, old_categories, new_categories):
"""
Convert a set of codes for to a new set of categories
Parameters
----------
codes : np.ndarray
old_categories, new_categories : Index
Returns
-------
new_codes : np.ndarray[np.int64]
Examples
--------
>>> old_cat = pd.Index(['b', 'a', 'c'])
>>> new_cat = pd.Index(['a', 'b'])
>>> codes = np.array([0, 1, 1, 2])
>>> _recode_for_categories(codes, old_cat, new_cat)
array([ 1, 0, 0, -1])
"""
if len(old_categories) == 0:
# All null anyway, so just retain the nulls
return codes.copy()
elif new_categories.equals(old_categories):
# Same categories, so no need to actually recode
return codes.copy()
indexer = coerce_indexer_dtype(
new_categories.get_indexer(old_categories), new_categories
)
new_codes = take_1d(indexer, codes.copy(), fill_value=-1)
return new_codes
def _convert_to_list_like(list_like):
if hasattr(list_like, "dtype"):
return list_like
if isinstance(list_like, list):
return list_like
if is_sequence(list_like) or isinstance(list_like, tuple) or is_iterator(list_like):
return list(list_like)
elif is_scalar(list_like):
return [list_like]
else:
# TODO: is this reached?
return [list_like]
def factorize_from_iterable(values):
"""
Factorize an input `values` into `categories` and `codes`. Preserves
categorical dtype in `categories`.
*This is an internal function*
Parameters
----------
values : list-like
Returns
-------
codes : ndarray
categories : Index
If `values` has a categorical dtype, then `categories` is
a CategoricalIndex keeping the categories and order of `values`.
"""
if not is_list_like(values):
raise TypeError("Input must be list-like")
if is_categorical_dtype(values):
values = extract_array(values)
# The Categorical we want to build has the same categories
# as values but its codes are by def [0, ..., len(n_categories) - 1]
cat_codes = np.arange(len(values.categories), dtype=values.codes.dtype)
categories = Categorical.from_codes(cat_codes, dtype=values.dtype)
codes = values.codes
else:
# The value of ordered is irrelevant since we don't use cat as such,
# but only the resulting categories, the order of which is independent
# from ordered. Set ordered to False as default. See GH #15457
cat = Categorical(values, ordered=False)
categories = cat.categories
codes = cat.codes
return codes, categories
def factorize_from_iterables(iterables):
"""
A higher-level wrapper over `factorize_from_iterable`.
*This is an internal function*
Parameters
----------
iterables : list-like of list-likes
Returns
-------
codes_list : list of ndarrays
categories_list : list of Indexes
Notes
-----
See `factorize_from_iterable` for more info.
"""
if len(iterables) == 0:
# For consistency, it should return a list of 2 lists.
return [[], []]
return map(list, zip(*(factorize_from_iterable(it) for it in iterables)))
| BugsInPy/BugsInPy/temp/projects/pandas/bug-125-fixed/pandas/pandas/core/arrays/categorical.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-125-buggy/pandas/pandas/core/arrays/categorical.py |
pandas-bug-144 | import re
from typing import Optional
import warnings
import numpy as np
from pandas._config import get_option
from pandas.errors import AbstractMethodError
from pandas.util._decorators import cache_readonly
from pandas.core.dtypes.common import (
is_hashable,
is_integer,
is_iterator,
is_list_like,
is_number,
)
from pandas.core.dtypes.generic import (
ABCDataFrame,
ABCIndexClass,
ABCMultiIndex,
ABCPeriodIndex,
ABCSeries,
)
from pandas.core.dtypes.missing import isna, notna
import pandas.core.common as com
from pandas.io.formats.printing import pprint_thing
from pandas.plotting._matplotlib import converter
from pandas.plotting._matplotlib.compat import _mpl_ge_3_0_0
from pandas.plotting._matplotlib.style import _get_standard_colors
from pandas.plotting._matplotlib.tools import (
_flatten,
_get_all_lines,
_get_xlim,
_handle_shared_axes,
_subplots,
format_date_labels,
table,
)
if get_option("plotting.matplotlib.register_converters"):
converter.register(explicit=False)
class MPLPlot:
"""
Base class for assembling a pandas plot using matplotlib
Parameters
----------
data :
"""
@property
def _kind(self):
"""Specify kind str. Must be overridden in child class"""
raise NotImplementedError
_layout_type = "vertical"
_default_rot = 0
orientation = None # type: Optional[str]
_pop_attributes = [
"label",
"style",
"logy",
"logx",
"loglog",
"mark_right",
"stacked",
]
_attr_defaults = {
"logy": False,
"logx": False,
"loglog": False,
"mark_right": True,
"stacked": False,
}
def __init__(
self,
data,
kind=None,
by=None,
subplots=False,
sharex=None,
sharey=False,
use_index=True,
figsize=None,
grid=None,
legend=True,
rot=None,
ax=None,
fig=None,
title=None,
xlim=None,
ylim=None,
xticks=None,
yticks=None,
sort_columns=False,
fontsize=None,
secondary_y=False,
colormap=None,
table=False,
layout=None,
include_bool=False,
**kwds
):
import matplotlib.pyplot as plt
converter._WARN = False # no warning for pandas plots
self.data = data
self.by = by
self.kind = kind
self.sort_columns = sort_columns
self.subplots = subplots
if sharex is None:
if ax is None:
self.sharex = True
else:
# if we get an axis, the users should do the visibility
# setting...
self.sharex = False
else:
self.sharex = sharex
self.sharey = sharey
self.figsize = figsize
self.layout = layout
self.xticks = xticks
self.yticks = yticks
self.xlim = xlim
self.ylim = ylim
self.title = title
self.use_index = use_index
self.fontsize = fontsize
if rot is not None:
self.rot = rot
# need to know for format_date_labels since it's rotated to 30 by
# default
self._rot_set = True
else:
self._rot_set = False
self.rot = self._default_rot
if grid is None:
grid = False if secondary_y else plt.rcParams["axes.grid"]
self.grid = grid
self.legend = legend
self.legend_handles = []
self.legend_labels = []
for attr in self._pop_attributes:
value = kwds.pop(attr, self._attr_defaults.get(attr, None))
setattr(self, attr, value)
self.ax = ax
self.fig = fig
self.axes = None
# parse errorbar input if given
xerr = kwds.pop("xerr", None)
yerr = kwds.pop("yerr", None)
self.errors = {
kw: self._parse_errorbars(kw, err)
for kw, err in zip(["xerr", "yerr"], [xerr, yerr])
}
if not isinstance(secondary_y, (bool, tuple, list, np.ndarray, ABCIndexClass)):
secondary_y = [secondary_y]
self.secondary_y = secondary_y
# ugly TypeError if user passes matplotlib's `cmap` name.
# Probably better to accept either.
if "cmap" in kwds and colormap:
raise TypeError("Only specify one of `cmap` and `colormap`.")
elif "cmap" in kwds:
self.colormap = kwds.pop("cmap")
else:
self.colormap = colormap
self.table = table
self.include_bool = include_bool
self.kwds = kwds
self._validate_color_args()
def _validate_color_args(self):
if "color" not in self.kwds and "colors" in self.kwds:
warnings.warn(
(
"'colors' is being deprecated. Please use 'color'"
"instead of 'colors'"
)
)
colors = self.kwds.pop("colors")
self.kwds["color"] = colors
if (
"color" in self.kwds
and self.nseries == 1
and not is_list_like(self.kwds["color"])
):
# support series.plot(color='green')
self.kwds["color"] = [self.kwds["color"]]
if (
"color" in self.kwds
and isinstance(self.kwds["color"], tuple)
and self.nseries == 1
and len(self.kwds["color"]) in (3, 4)
):
# support RGB and RGBA tuples in series plot
self.kwds["color"] = [self.kwds["color"]]
if (
"color" in self.kwds or "colors" in self.kwds
) and self.colormap is not None:
warnings.warn(
"'color' and 'colormap' cannot be used " "simultaneously. Using 'color'"
)
if "color" in self.kwds and self.style is not None:
if is_list_like(self.style):
styles = self.style
else:
styles = [self.style]
# need only a single match
for s in styles:
if re.match("^[a-z]+?", s) is not None:
raise ValueError(
"Cannot pass 'style' string with a color "
"symbol and 'color' keyword argument. Please"
" use one or the other or pass 'style' "
"without a color symbol"
)
def _iter_data(self, data=None, keep_index=False, fillna=None):
if data is None:
data = self.data
if fillna is not None:
data = data.fillna(fillna)
# TODO: unused?
# if self.sort_columns:
# columns = com.try_sort(data.columns)
# else:
# columns = data.columns
for col, values in data.items():
if keep_index is True:
yield col, values
else:
yield col, values.values
@property
def nseries(self):
if self.data.ndim == 1:
return 1
else:
return self.data.shape[1]
def draw(self):
self.plt.draw_if_interactive()
def generate(self):
self._args_adjust()
self._compute_plot_data()
self._setup_subplots()
self._make_plot()
self._add_table()
self._make_legend()
self._adorn_subplots()
for ax in self.axes:
self._post_plot_logic_common(ax, self.data)
self._post_plot_logic(ax, self.data)
def _args_adjust(self):
pass
def _has_plotted_object(self, ax):
"""check whether ax has data"""
return len(ax.lines) != 0 or len(ax.artists) != 0 or len(ax.containers) != 0
def _maybe_right_yaxis(self, ax, axes_num):
if not self.on_right(axes_num):
# secondary axes may be passed via ax kw
return self._get_ax_layer(ax)
if hasattr(ax, "right_ax"):
# if it has right_ax proparty, ``ax`` must be left axes
return ax.right_ax
elif hasattr(ax, "left_ax"):
# if it has left_ax proparty, ``ax`` must be right axes
return ax
else:
# otherwise, create twin axes
orig_ax, new_ax = ax, ax.twinx()
# TODO: use Matplotlib public API when available
new_ax._get_lines = orig_ax._get_lines
new_ax._get_patches_for_fill = orig_ax._get_patches_for_fill
orig_ax.right_ax, new_ax.left_ax = new_ax, orig_ax
if not self._has_plotted_object(orig_ax): # no data on left y
orig_ax.get_yaxis().set_visible(False)
if self.logy is True or self.loglog is True:
new_ax.set_yscale("log")
elif self.logy == "sym" or self.loglog == "sym":
new_ax.set_yscale("symlog")
return new_ax
def _setup_subplots(self):
if self.subplots:
fig, axes = _subplots(
naxes=self.nseries,
sharex=self.sharex,
sharey=self.sharey,
figsize=self.figsize,
ax=self.ax,
layout=self.layout,
layout_type=self._layout_type,
)
else:
if self.ax is None:
fig = self.plt.figure(figsize=self.figsize)
axes = fig.add_subplot(111)
else:
fig = self.ax.get_figure()
if self.figsize is not None:
fig.set_size_inches(self.figsize)
axes = self.ax
axes = _flatten(axes)
valid_log = {False, True, "sym", None}
input_log = {self.logx, self.logy, self.loglog}
if input_log - valid_log:
invalid_log = next(iter((input_log - valid_log)))
raise ValueError(
"Boolean, None and 'sym' are valid options,"
" '{}' is given.".format(invalid_log)
)
if self.logx is True or self.loglog is True:
[a.set_xscale("log") for a in axes]
elif self.logx == "sym" or self.loglog == "sym":
[a.set_xscale("symlog") for a in axes]
if self.logy is True or self.loglog is True:
[a.set_yscale("log") for a in axes]
elif self.logy == "sym" or self.loglog == "sym":
[a.set_yscale("symlog") for a in axes]
self.fig = fig
self.axes = axes
@property
def result(self):
"""
Return result axes
"""
if self.subplots:
if self.layout is not None and not is_list_like(self.ax):
return self.axes.reshape(*self.layout)
else:
return self.axes
else:
sec_true = isinstance(self.secondary_y, bool) and self.secondary_y
all_sec = (
is_list_like(self.secondary_y) and len(self.secondary_y) == self.nseries
)
if sec_true or all_sec:
# if all data is plotted on secondary, return right axes
return self._get_ax_layer(self.axes[0], primary=False)
else:
return self.axes[0]
def _compute_plot_data(self):
data = self.data
if isinstance(data, ABCSeries):
label = self.label
if label is None and data.name is None:
label = "None"
data = data.to_frame(name=label)
# GH16953, _convert is needed as fallback, for ``Series``
# with ``dtype == object``
data = data._convert(datetime=True, timedelta=True)
include_type = [np.number, "datetime", "datetimetz", "timedelta"]
# GH23719, allow plotting boolean
if self.include_bool is True:
include_type.append(np.bool_)
# GH22799, exclude datatime-like type for boxplot
exclude_type = None
if self._kind == "box":
# TODO: change after solving issue 27881
include_type = [np.number]
exclude_type = ["timedelta"]
numeric_data = data.select_dtypes(include=include_type, exclude=exclude_type)
try:
is_empty = numeric_data.columns.empty
except AttributeError:
is_empty = not len(numeric_data)
# no non-numeric frames or series allowed
if is_empty:
raise TypeError("no numeric data to plot")
# GH25587: cast ExtensionArray of pandas (IntegerArray, etc.) to
# np.ndarray before plot.
numeric_data = numeric_data.copy()
for col in numeric_data:
numeric_data[col] = np.asarray(numeric_data[col])
self.data = numeric_data
def _make_plot(self):
raise AbstractMethodError(self)
def _add_table(self):
if self.table is False:
return
elif self.table is True:
data = self.data.transpose()
else:
data = self.table
ax = self._get_ax(0)
table(ax, data)
def _post_plot_logic_common(self, ax, data):
"""Common post process for each axes"""
if self.orientation == "vertical" or self.orientation is None:
self._apply_axis_properties(ax.xaxis, rot=self.rot, fontsize=self.fontsize)
self._apply_axis_properties(ax.yaxis, fontsize=self.fontsize)
if hasattr(ax, "right_ax"):
self._apply_axis_properties(ax.right_ax.yaxis, fontsize=self.fontsize)
elif self.orientation == "horizontal":
self._apply_axis_properties(ax.yaxis, rot=self.rot, fontsize=self.fontsize)
self._apply_axis_properties(ax.xaxis, fontsize=self.fontsize)
if hasattr(ax, "right_ax"):
self._apply_axis_properties(ax.right_ax.yaxis, fontsize=self.fontsize)
else: # pragma no cover
raise ValueError
def _post_plot_logic(self, ax, data):
"""Post process for each axes. Overridden in child classes"""
pass
def _adorn_subplots(self):
"""Common post process unrelated to data"""
if len(self.axes) > 0:
all_axes = self._get_subplots()
nrows, ncols = self._get_axes_layout()
_handle_shared_axes(
axarr=all_axes,
nplots=len(all_axes),
naxes=nrows * ncols,
nrows=nrows,
ncols=ncols,
sharex=self.sharex,
sharey=self.sharey,
)
for ax in self.axes:
if self.yticks is not None:
ax.set_yticks(self.yticks)
if self.xticks is not None:
ax.set_xticks(self.xticks)
if self.ylim is not None:
ax.set_ylim(self.ylim)
if self.xlim is not None:
ax.set_xlim(self.xlim)
ax.grid(self.grid)
if self.title:
if self.subplots:
if is_list_like(self.title):
if len(self.title) != self.nseries:
msg = (
"The length of `title` must equal the number "
"of columns if using `title` of type `list` "
"and `subplots=True`.\n"
"length of title = {}\n"
"number of columns = {}"
).format(len(self.title), self.nseries)
raise ValueError(msg)
for (ax, title) in zip(self.axes, self.title):
ax.set_title(title)
else:
self.fig.suptitle(self.title)
else:
if is_list_like(self.title):
msg = (
"Using `title` of type `list` is not supported "
"unless `subplots=True` is passed"
)
raise ValueError(msg)
self.axes[0].set_title(self.title)
def _apply_axis_properties(self, axis, rot=None, fontsize=None):
""" Tick creation within matplotlib is reasonably expensive and is
internally deferred until accessed as Ticks are created/destroyed
multiple times per draw. It's therefore beneficial for us to avoid
accessing unless we will act on the Tick.
"""
if rot is not None or fontsize is not None:
# rot=0 is a valid setting, hence the explicit None check
labels = axis.get_majorticklabels() + axis.get_minorticklabels()
for label in labels:
if rot is not None:
label.set_rotation(rot)
if fontsize is not None:
label.set_fontsize(fontsize)
@property
def legend_title(self):
if not isinstance(self.data.columns, ABCMultiIndex):
name = self.data.columns.name
if name is not None:
name = pprint_thing(name)
return name
else:
stringified = map(pprint_thing, self.data.columns.names)
return ",".join(stringified)
def _add_legend_handle(self, handle, label, index=None):
if label is not None:
if self.mark_right and index is not None:
if self.on_right(index):
label = label + " (right)"
self.legend_handles.append(handle)
self.legend_labels.append(label)
def _make_legend(self):
ax, leg, handle = self._get_ax_legend_handle(self.axes[0])
handles = []
labels = []
title = ""
if not self.subplots:
if leg is not None:
title = leg.get_title().get_text()
# Replace leg.LegendHandles because it misses marker info
handles.extend(handle)
labels = [x.get_text() for x in leg.get_texts()]
if self.legend:
if self.legend == "reverse":
self.legend_handles = reversed(self.legend_handles)
self.legend_labels = reversed(self.legend_labels)
handles += self.legend_handles
labels += self.legend_labels
if self.legend_title is not None:
title = self.legend_title
if len(handles) > 0:
ax.legend(handles, labels, loc="best", title=title)
elif self.subplots and self.legend:
for ax in self.axes:
if ax.get_visible():
ax.legend(loc="best")
def _get_ax_legend_handle(self, ax):
"""
Take in axes and return ax, legend and handle under different scenarios
"""
leg = ax.get_legend()
# Get handle from axes
handle, _ = ax.get_legend_handles_labels()
other_ax = getattr(ax, "left_ax", None) or getattr(ax, "right_ax", None)
other_leg = None
if other_ax is not None:
other_leg = other_ax.get_legend()
if leg is None and other_leg is not None:
leg = other_leg
ax = other_ax
return ax, leg, handle
@cache_readonly
def plt(self):
import matplotlib.pyplot as plt
return plt
_need_to_set_index = False
def _get_xticks(self, convert_period=False):
index = self.data.index
is_datetype = index.inferred_type in ("datetime", "date", "datetime64", "time")
if self.use_index:
if convert_period and isinstance(index, ABCPeriodIndex):
self.data = self.data.reindex(index=index.sort_values())
x = self.data.index.to_timestamp()._mpl_repr()
elif index.is_numeric():
"""
Matplotlib supports numeric values or datetime objects as
xaxis values. Taking LBYL approach here, by the time
matplotlib raises exception when using non numeric/datetime
values for xaxis, several actions are already taken by plt.
"""
x = index._mpl_repr()
elif is_datetype:
self.data = self.data[notna(self.data.index)]
self.data = self.data.sort_index()
x = self.data.index._mpl_repr()
else:
self._need_to_set_index = True
x = list(range(len(index)))
else:
x = list(range(len(index)))
return x
@classmethod
def _plot(cls, ax, x, y, style=None, is_errorbar=False, **kwds):
mask = isna(y)
if mask.any():
y = np.ma.array(y)
y = np.ma.masked_where(mask, y)
if isinstance(x, ABCIndexClass):
x = x._mpl_repr()
if is_errorbar:
if "xerr" in kwds:
kwds["xerr"] = np.array(kwds.get("xerr"))
if "yerr" in kwds:
kwds["yerr"] = np.array(kwds.get("yerr"))
return ax.errorbar(x, y, **kwds)
else:
# prevent style kwarg from going to errorbar, where it is
# unsupported
if style is not None:
args = (x, y, style)
else:
args = (x, y)
return ax.plot(*args, **kwds)
def _get_index_name(self):
if isinstance(self.data.index, ABCMultiIndex):
name = self.data.index.names
if com.any_not_none(*name):
name = ",".join(pprint_thing(x) for x in name)
else:
name = None
else:
name = self.data.index.name
if name is not None:
name = pprint_thing(name)
return name
@classmethod
def _get_ax_layer(cls, ax, primary=True):
"""get left (primary) or right (secondary) axes"""
if primary:
return getattr(ax, "left_ax", ax)
else:
return getattr(ax, "right_ax", ax)
def _get_ax(self, i):
# get the twinx ax if appropriate
if self.subplots:
ax = self.axes[i]
ax = self._maybe_right_yaxis(ax, i)
self.axes[i] = ax
else:
ax = self.axes[0]
ax = self._maybe_right_yaxis(ax, i)
ax.get_yaxis().set_visible(True)
return ax
@classmethod
def get_default_ax(cls, ax):
import matplotlib.pyplot as plt
if ax is None and len(plt.get_fignums()) > 0:
with plt.rc_context():
ax = plt.gca()
ax = cls._get_ax_layer(ax)
def on_right(self, i):
if isinstance(self.secondary_y, bool):
return self.secondary_y
if isinstance(self.secondary_y, (tuple, list, np.ndarray, ABCIndexClass)):
return self.data.columns[i] in self.secondary_y
def _apply_style_colors(self, colors, kwds, col_num, label):
"""
Manage style and color based on column number and its label.
Returns tuple of appropriate style and kwds which "color" may be added.
"""
style = None
if self.style is not None:
if isinstance(self.style, list):
try:
style = self.style[col_num]
except IndexError:
pass
elif isinstance(self.style, dict):
style = self.style.get(label, style)
else:
style = self.style
has_color = "color" in kwds or self.colormap is not None
nocolor_style = style is None or re.match("[a-z]+", style) is None
if (has_color or self.subplots) and nocolor_style:
kwds["color"] = colors[col_num % len(colors)]
return style, kwds
def _get_colors(self, num_colors=None, color_kwds="color"):
if num_colors is None:
num_colors = self.nseries
return _get_standard_colors(
num_colors=num_colors,
colormap=self.colormap,
color=self.kwds.get(color_kwds),
)
def _parse_errorbars(self, label, err):
"""
Look for error keyword arguments and return the actual errorbar data
or return the error DataFrame/dict
Error bars can be specified in several ways:
Series: the user provides a pandas.Series object of the same
length as the data
ndarray: provides a np.ndarray of the same length as the data
DataFrame/dict: error values are paired with keys matching the
key in the plotted DataFrame
str: the name of the column within the plotted DataFrame
"""
if err is None:
return None
def match_labels(data, e):
e = e.reindex(data.index)
return e
# key-matched DataFrame
if isinstance(err, ABCDataFrame):
err = match_labels(self.data, err)
# key-matched dict
elif isinstance(err, dict):
pass
# Series of error values
elif isinstance(err, ABCSeries):
# broadcast error series across data
err = match_labels(self.data, err)
err = np.atleast_2d(err)
err = np.tile(err, (self.nseries, 1))
# errors are a column in the dataframe
elif isinstance(err, str):
evalues = self.data[err].values
self.data = self.data[self.data.columns.drop(err)]
err = np.atleast_2d(evalues)
err = np.tile(err, (self.nseries, 1))
elif is_list_like(err):
if is_iterator(err):
err = np.atleast_2d(list(err))
else:
# raw error values
err = np.atleast_2d(err)
err_shape = err.shape
# asymmetrical error bars
if err.ndim == 3:
if (
(err_shape[0] != self.nseries)
or (err_shape[1] != 2)
or (err_shape[2] != len(self.data))
):
msg = (
"Asymmetrical error bars should be provided "
+ "with the shape (%u, 2, %u)" % (self.nseries, len(self.data))
)
raise ValueError(msg)
# broadcast errors to each data series
if len(err) == 1:
err = np.tile(err, (self.nseries, 1))
elif is_number(err):
err = np.tile([err], (self.nseries, len(self.data)))
else:
msg = "No valid {label} detected".format(label=label)
raise ValueError(msg)
return err
def _get_errorbars(self, label=None, index=None, xerr=True, yerr=True):
errors = {}
for kw, flag in zip(["xerr", "yerr"], [xerr, yerr]):
if flag:
err = self.errors[kw]
# user provided label-matched dataframe of errors
if isinstance(err, (ABCDataFrame, dict)):
if label is not None and label in err.keys():
err = err[label]
else:
err = None
elif index is not None and err is not None:
err = err[index]
if err is not None:
errors[kw] = err
return errors
def _get_subplots(self):
from matplotlib.axes import Subplot
return [
ax for ax in self.axes[0].get_figure().get_axes() if isinstance(ax, Subplot)
]
def _get_axes_layout(self):
axes = self._get_subplots()
x_set = set()
y_set = set()
for ax in axes:
# check axes coordinates to estimate layout
points = ax.get_position().get_points()
x_set.add(points[0][0])
y_set.add(points[0][1])
return (len(y_set), len(x_set))
class PlanePlot(MPLPlot):
"""
Abstract class for plotting on plane, currently scatter and hexbin.
"""
_layout_type = "single"
def __init__(self, data, x, y, **kwargs):
MPLPlot.__init__(self, data, **kwargs)
if x is None or y is None:
raise ValueError(self._kind + " requires an x and y column")
if is_integer(x) and not self.data.columns.holds_integer():
x = self.data.columns[x]
if is_integer(y) and not self.data.columns.holds_integer():
y = self.data.columns[y]
if len(self.data[x]._get_numeric_data()) == 0:
raise ValueError(self._kind + " requires x column to be numeric")
if len(self.data[y]._get_numeric_data()) == 0:
raise ValueError(self._kind + " requires y column to be numeric")
self.x = x
self.y = y
@property
def nseries(self):
return 1
def _post_plot_logic(self, ax, data):
x, y = self.x, self.y
ax.set_ylabel(pprint_thing(y))
ax.set_xlabel(pprint_thing(x))
def _plot_colorbar(self, ax, **kwds):
# Addresses issues #10611 and #10678:
# When plotting scatterplots and hexbinplots in IPython
# inline backend the colorbar axis height tends not to
# exactly match the parent axis height.
# The difference is due to small fractional differences
# in floating points with similar representation.
# To deal with this, this method forces the colorbar
# height to take the height of the parent axes.
# For a more detailed description of the issue
# see the following link:
# https://github.com/ipython/ipython/issues/11215
img = ax.collections[0]
cbar = self.fig.colorbar(img, ax=ax, **kwds)
if _mpl_ge_3_0_0():
# The workaround below is no longer necessary.
return
points = ax.get_position().get_points()
cbar_points = cbar.ax.get_position().get_points()
cbar.ax.set_position(
[
cbar_points[0, 0],
points[0, 1],
cbar_points[1, 0] - cbar_points[0, 0],
points[1, 1] - points[0, 1],
]
)
# To see the discrepancy in axis heights uncomment
# the following two lines:
# print(points[1, 1] - points[0, 1])
# print(cbar_points[1, 1] - cbar_points[0, 1])
class ScatterPlot(PlanePlot):
_kind = "scatter"
def __init__(self, data, x, y, s=None, c=None, **kwargs):
if s is None:
# hide the matplotlib default for size, in case we want to change
# the handling of this argument later
s = 20
super().__init__(data, x, y, s=s, **kwargs)
if is_integer(c) and not self.data.columns.holds_integer():
c = self.data.columns[c]
self.c = c
def _make_plot(self):
x, y, c, data = self.x, self.y, self.c, self.data
ax = self.axes[0]
c_is_column = is_hashable(c) and c in self.data.columns
# plot a colorbar only if a colormap is provided or necessary
cb = self.kwds.pop("colorbar", self.colormap or c_is_column)
# pandas uses colormap, matplotlib uses cmap.
cmap = self.colormap or "Greys"
cmap = self.plt.cm.get_cmap(cmap)
color = self.kwds.pop("color", None)
if c is not None and color is not None:
raise TypeError("Specify exactly one of `c` and `color`")
elif c is None and color is None:
c_values = self.plt.rcParams["patch.facecolor"]
elif color is not None:
c_values = color
elif c_is_column:
c_values = self.data[c].values
else:
c_values = c
if self.legend and hasattr(self, "label"):
label = self.label
else:
label = None
scatter = ax.scatter(
data[x].values,
data[y].values,
c=c_values,
label=label,
cmap=cmap,
**self.kwds
)
if cb:
cbar_label = c if c_is_column else ""
self._plot_colorbar(ax, label=cbar_label)
if label is not None:
self._add_legend_handle(scatter, label)
else:
self.legend = False
errors_x = self._get_errorbars(label=x, index=0, yerr=False)
errors_y = self._get_errorbars(label=y, index=0, xerr=False)
if len(errors_x) > 0 or len(errors_y) > 0:
err_kwds = dict(errors_x, **errors_y)
err_kwds["ecolor"] = scatter.get_facecolor()[0]
ax.errorbar(data[x].values, data[y].values, linestyle="none", **err_kwds)
class HexBinPlot(PlanePlot):
_kind = "hexbin"
def __init__(self, data, x, y, C=None, **kwargs):
super().__init__(data, x, y, **kwargs)
if is_integer(C) and not self.data.columns.holds_integer():
C = self.data.columns[C]
self.C = C
def _make_plot(self):
x, y, data, C = self.x, self.y, self.data, self.C
ax = self.axes[0]
# pandas uses colormap, matplotlib uses cmap.
cmap = self.colormap or "BuGn"
cmap = self.plt.cm.get_cmap(cmap)
cb = self.kwds.pop("colorbar", True)
if C is None:
c_values = None
else:
c_values = data[C].values
ax.hexbin(data[x].values, data[y].values, C=c_values, cmap=cmap, **self.kwds)
if cb:
self._plot_colorbar(ax)
def _make_legend(self):
pass
class LinePlot(MPLPlot):
_kind = "line"
_default_rot = 0
orientation = "vertical"
def __init__(self, data, **kwargs):
from pandas.plotting import plot_params
MPLPlot.__init__(self, data, **kwargs)
if self.stacked:
self.data = self.data.fillna(value=0)
self.x_compat = plot_params["x_compat"]
if "x_compat" in self.kwds:
self.x_compat = bool(self.kwds.pop("x_compat"))
def _is_ts_plot(self):
# this is slightly deceptive
return not self.x_compat and self.use_index and self._use_dynamic_x()
def _use_dynamic_x(self):
from pandas.plotting._matplotlib.timeseries import _use_dynamic_x
return _use_dynamic_x(self._get_ax(0), self.data)
def _make_plot(self):
if self._is_ts_plot():
from pandas.plotting._matplotlib.timeseries import _maybe_convert_index
data = _maybe_convert_index(self._get_ax(0), self.data)
x = data.index # dummy, not used
plotf = self._ts_plot
it = self._iter_data(data=data, keep_index=True)
else:
x = self._get_xticks(convert_period=True)
plotf = self._plot
it = self._iter_data()
stacking_id = self._get_stacking_id()
is_errorbar = com.any_not_none(*self.errors.values())
colors = self._get_colors()
for i, (label, y) in enumerate(it):
ax = self._get_ax(i)
kwds = self.kwds.copy()
style, kwds = self._apply_style_colors(colors, kwds, i, label)
errors = self._get_errorbars(label=label, index=i)
kwds = dict(kwds, **errors)
label = pprint_thing(label) # .encode('utf-8')
kwds["label"] = label
newlines = plotf(
ax,
x,
y,
style=style,
column_num=i,
stacking_id=stacking_id,
is_errorbar=is_errorbar,
**kwds
)
self._add_legend_handle(newlines[0], label, index=i)
if self._is_ts_plot():
# reset of xlim should be used for ts data
# TODO: GH28021, should find a way to change view limit on xaxis
lines = _get_all_lines(ax)
left, right = _get_xlim(lines)
ax.set_xlim(left, right)
@classmethod
def _plot(cls, ax, x, y, style=None, column_num=None, stacking_id=None, **kwds):
# column_num is used to get the target column from protf in line and
# area plots
if column_num == 0:
cls._initialize_stacker(ax, stacking_id, len(y))
y_values = cls._get_stacked_values(ax, stacking_id, y, kwds["label"])
lines = MPLPlot._plot(ax, x, y_values, style=style, **kwds)
cls._update_stacker(ax, stacking_id, y)
return lines
@classmethod
def _ts_plot(cls, ax, x, data, style=None, **kwds):
from pandas.plotting._matplotlib.timeseries import (
_maybe_resample,
_decorate_axes,
format_dateaxis,
)
# accept x to be consistent with normal plot func,
# x is not passed to tsplot as it uses data.index as x coordinate
# column_num must be in kwds for stacking purpose
freq, data = _maybe_resample(data, ax, kwds)
# Set ax with freq info
_decorate_axes(ax, freq, kwds)
# digging deeper
if hasattr(ax, "left_ax"):
_decorate_axes(ax.left_ax, freq, kwds)
if hasattr(ax, "right_ax"):
_decorate_axes(ax.right_ax, freq, kwds)
ax._plot_data.append((data, cls._kind, kwds))
lines = cls._plot(ax, data.index, data.values, style=style, **kwds)
# set date formatter, locators and rescale limits
format_dateaxis(ax, ax.freq, data.index)
return lines
def _get_stacking_id(self):
if self.stacked:
return id(self.data)
else:
return None
@classmethod
def _initialize_stacker(cls, ax, stacking_id, n):
if stacking_id is None:
return
if not hasattr(ax, "_stacker_pos_prior"):
ax._stacker_pos_prior = {}
if not hasattr(ax, "_stacker_neg_prior"):
ax._stacker_neg_prior = {}
ax._stacker_pos_prior[stacking_id] = np.zeros(n)
ax._stacker_neg_prior[stacking_id] = np.zeros(n)
@classmethod
def _get_stacked_values(cls, ax, stacking_id, values, label):
if stacking_id is None:
return values
if not hasattr(ax, "_stacker_pos_prior"):
# stacker may not be initialized for subplots
cls._initialize_stacker(ax, stacking_id, len(values))
if (values >= 0).all():
return ax._stacker_pos_prior[stacking_id] + values
elif (values <= 0).all():
return ax._stacker_neg_prior[stacking_id] + values
raise ValueError(
"When stacked is True, each column must be either "
"all positive or negative."
"{0} contains both positive and negative values".format(label)
)
@classmethod
def _update_stacker(cls, ax, stacking_id, values):
if stacking_id is None:
return
if (values >= 0).all():
ax._stacker_pos_prior[stacking_id] += values
elif (values <= 0).all():
ax._stacker_neg_prior[stacking_id] += values
def _post_plot_logic(self, ax, data):
from matplotlib.ticker import FixedLocator
def get_label(i):
try:
return pprint_thing(data.index[i])
except Exception:
return ""
if self._need_to_set_index:
xticks = ax.get_xticks()
xticklabels = [get_label(x) for x in xticks]
ax.set_xticklabels(xticklabels)
ax.xaxis.set_major_locator(FixedLocator(xticks))
condition = (
not self._use_dynamic_x()
and data.index.is_all_dates
and not self.subplots
or (self.subplots and self.sharex)
)
index_name = self._get_index_name()
if condition:
# irregular TS rotated 30 deg. by default
# probably a better place to check / set this.
if not self._rot_set:
self.rot = 30
format_date_labels(ax, rot=self.rot)
if index_name is not None and self.use_index:
ax.set_xlabel(index_name)
class AreaPlot(LinePlot):
_kind = "area"
def __init__(self, data, **kwargs):
kwargs.setdefault("stacked", True)
data = data.fillna(value=0)
LinePlot.__init__(self, data, **kwargs)
if not self.stacked:
# use smaller alpha to distinguish overlap
self.kwds.setdefault("alpha", 0.5)
if self.logy or self.loglog:
raise ValueError("Log-y scales are not supported in area plot")
@classmethod
def _plot(
cls,
ax,
x,
y,
style=None,
column_num=None,
stacking_id=None,
is_errorbar=False,
**kwds
):
if column_num == 0:
cls._initialize_stacker(ax, stacking_id, len(y))
y_values = cls._get_stacked_values(ax, stacking_id, y, kwds["label"])
# need to remove label, because subplots uses mpl legend as it is
line_kwds = kwds.copy()
line_kwds.pop("label")
lines = MPLPlot._plot(ax, x, y_values, style=style, **line_kwds)
# get data from the line to get coordinates for fill_between
xdata, y_values = lines[0].get_data(orig=False)
# unable to use ``_get_stacked_values`` here to get starting point
if stacking_id is None:
start = np.zeros(len(y))
elif (y >= 0).all():
start = ax._stacker_pos_prior[stacking_id]
elif (y <= 0).all():
start = ax._stacker_neg_prior[stacking_id]
else:
start = np.zeros(len(y))
if "color" not in kwds:
kwds["color"] = lines[0].get_color()
rect = ax.fill_between(xdata, start, y_values, **kwds)
cls._update_stacker(ax, stacking_id, y)
# LinePlot expects list of artists
res = [rect]
return res
def _post_plot_logic(self, ax, data):
LinePlot._post_plot_logic(self, ax, data)
if self.ylim is None:
if (data >= 0).all().all():
ax.set_ylim(0, None)
elif (data <= 0).all().all():
ax.set_ylim(None, 0)
class BarPlot(MPLPlot):
_kind = "bar"
_default_rot = 90
orientation = "vertical"
def __init__(self, data, **kwargs):
# we have to treat a series differently than a
# 1-column DataFrame w.r.t. color handling
self._is_series = isinstance(data, ABCSeries)
self.bar_width = kwargs.pop("width", 0.5)
pos = kwargs.pop("position", 0.5)
kwargs.setdefault("align", "center")
self.tick_pos = np.arange(len(data))
self.bottom = kwargs.pop("bottom", 0)
self.left = kwargs.pop("left", 0)
self.log = kwargs.pop("log", False)
MPLPlot.__init__(self, data, **kwargs)
if self.stacked or self.subplots:
self.tickoffset = self.bar_width * pos
if kwargs["align"] == "edge":
self.lim_offset = self.bar_width / 2
else:
self.lim_offset = 0
else:
if kwargs["align"] == "edge":
w = self.bar_width / self.nseries
self.tickoffset = self.bar_width * (pos - 0.5) + w * 0.5
self.lim_offset = w * 0.5
else:
self.tickoffset = self.bar_width * pos
self.lim_offset = 0
self.ax_pos = self.tick_pos - self.tickoffset
def _args_adjust(self):
if is_list_like(self.bottom):
self.bottom = np.array(self.bottom)
if is_list_like(self.left):
self.left = np.array(self.left)
@classmethod
def _plot(cls, ax, x, y, w, start=0, log=False, **kwds):
return ax.bar(x, y, w, bottom=start, log=log, **kwds)
@property
def _start_base(self):
return self.bottom
def _make_plot(self):
import matplotlib as mpl
colors = self._get_colors()
ncolors = len(colors)
pos_prior = neg_prior = np.zeros(len(self.data))
K = self.nseries
for i, (label, y) in enumerate(self._iter_data(fillna=0)):
ax = self._get_ax(i)
kwds = self.kwds.copy()
if self._is_series:
kwds["color"] = colors
else:
kwds["color"] = colors[i % ncolors]
errors = self._get_errorbars(label=label, index=i)
kwds = dict(kwds, **errors)
label = pprint_thing(label)
if (("yerr" in kwds) or ("xerr" in kwds)) and (kwds.get("ecolor") is None):
kwds["ecolor"] = mpl.rcParams["xtick.color"]
start = 0
if self.log and (y >= 1).all():
start = 1
start = start + self._start_base
if self.subplots:
w = self.bar_width / 2
rect = self._plot(
ax,
self.ax_pos + w,
y,
self.bar_width,
start=start,
label=label,
log=self.log,
**kwds
)
ax.set_title(label)
elif self.stacked:
mask = y > 0
start = np.where(mask, pos_prior, neg_prior) + self._start_base
w = self.bar_width / 2
rect = self._plot(
ax,
self.ax_pos + w,
y,
self.bar_width,
start=start,
label=label,
log=self.log,
**kwds
)
pos_prior = pos_prior + np.where(mask, y, 0)
neg_prior = neg_prior + np.where(mask, 0, y)
else:
w = self.bar_width / K
rect = self._plot(
ax,
self.ax_pos + (i + 0.5) * w,
y,
w,
start=start,
label=label,
log=self.log,
**kwds
)
self._add_legend_handle(rect, label, index=i)
def _post_plot_logic(self, ax, data):
if self.use_index:
str_index = [pprint_thing(key) for key in data.index]
else:
str_index = [pprint_thing(key) for key in range(data.shape[0])]
name = self._get_index_name()
s_edge = self.ax_pos[0] - 0.25 + self.lim_offset
e_edge = self.ax_pos[-1] + 0.25 + self.bar_width + self.lim_offset
self._decorate_ticks(ax, name, str_index, s_edge, e_edge)
def _decorate_ticks(self, ax, name, ticklabels, start_edge, end_edge):
ax.set_xlim((start_edge, end_edge))
ax.set_xticks(self.tick_pos)
ax.set_xticklabels(ticklabels)
if name is not None and self.use_index:
ax.set_xlabel(name)
class BarhPlot(BarPlot):
_kind = "barh"
_default_rot = 0
orientation = "horizontal"
@property
def _start_base(self):
return self.left
@classmethod
def _plot(cls, ax, x, y, w, start=0, log=False, **kwds):
return ax.barh(x, y, w, left=start, log=log, **kwds)
def _decorate_ticks(self, ax, name, ticklabels, start_edge, end_edge):
# horizontal bars
ax.set_ylim((start_edge, end_edge))
ax.set_yticks(self.tick_pos)
ax.set_yticklabels(ticklabels)
if name is not None and self.use_index:
ax.set_ylabel(name)
class PiePlot(MPLPlot):
_kind = "pie"
_layout_type = "horizontal"
def __init__(self, data, kind=None, **kwargs):
data = data.fillna(value=0)
if (data < 0).any().any():
raise ValueError("{0} doesn't allow negative values".format(kind))
MPLPlot.__init__(self, data, kind=kind, **kwargs)
def _args_adjust(self):
self.grid = False
self.logy = False
self.logx = False
self.loglog = False
def _validate_color_args(self):
pass
def _make_plot(self):
colors = self._get_colors(num_colors=len(self.data), color_kwds="colors")
self.kwds.setdefault("colors", colors)
for i, (label, y) in enumerate(self._iter_data()):
ax = self._get_ax(i)
if label is not None:
label = pprint_thing(label)
ax.set_ylabel(label)
kwds = self.kwds.copy()
def blank_labeler(label, value):
if value == 0:
return ""
else:
return label
idx = [pprint_thing(v) for v in self.data.index]
labels = kwds.pop("labels", idx)
# labels is used for each wedge's labels
# Blank out labels for values of 0 so they don't overlap
# with nonzero wedges
if labels is not None:
blabels = [blank_labeler(l, value) for l, value in zip(labels, y)]
else:
blabels = None
results = ax.pie(y, labels=blabels, **kwds)
if kwds.get("autopct", None) is not None:
patches, texts, autotexts = results
else:
patches, texts = results
autotexts = []
if self.fontsize is not None:
for t in texts + autotexts:
t.set_fontsize(self.fontsize)
# leglabels is used for legend labels
leglabels = labels if labels is not None else idx
for p, l in zip(patches, leglabels):
self._add_legend_handle(p, l)
import re
from typing import Optional
import warnings
import numpy as np
from pandas._config import get_option
from pandas.errors import AbstractMethodError
from pandas.util._decorators import cache_readonly
from pandas.core.dtypes.common import (
is_hashable,
is_integer,
is_iterator,
is_list_like,
is_number,
)
from pandas.core.dtypes.generic import (
ABCDataFrame,
ABCIndexClass,
ABCMultiIndex,
ABCPeriodIndex,
ABCSeries,
)
from pandas.core.dtypes.missing import isna, notna
import pandas.core.common as com
from pandas.io.formats.printing import pprint_thing
from pandas.plotting._matplotlib import converter
from pandas.plotting._matplotlib.compat import _mpl_ge_3_0_0
from pandas.plotting._matplotlib.style import _get_standard_colors
from pandas.plotting._matplotlib.tools import (
_flatten,
_get_all_lines,
_get_xlim,
_handle_shared_axes,
_subplots,
format_date_labels,
table,
)
if get_option("plotting.matplotlib.register_converters"):
converter.register(explicit=False)
class MPLPlot:
"""
Base class for assembling a pandas plot using matplotlib
Parameters
----------
data :
"""
@property
def _kind(self):
"""Specify kind str. Must be overridden in child class"""
raise NotImplementedError
_layout_type = "vertical"
_default_rot = 0
orientation = None # type: Optional[str]
_pop_attributes = [
"label",
"style",
"logy",
"logx",
"loglog",
"mark_right",
"stacked",
]
_attr_defaults = {
"logy": False,
"logx": False,
"loglog": False,
"mark_right": True,
"stacked": False,
}
def __init__(
self,
data,
kind=None,
by=None,
subplots=False,
sharex=None,
sharey=False,
use_index=True,
figsize=None,
grid=None,
legend=True,
rot=None,
ax=None,
fig=None,
title=None,
xlim=None,
ylim=None,
xticks=None,
yticks=None,
sort_columns=False,
fontsize=None,
secondary_y=False,
colormap=None,
table=False,
layout=None,
include_bool=False,
**kwds
):
import matplotlib.pyplot as plt
converter._WARN = False # no warning for pandas plots
self.data = data
self.by = by
self.kind = kind
self.sort_columns = sort_columns
self.subplots = subplots
if sharex is None:
if ax is None:
self.sharex = True
else:
# if we get an axis, the users should do the visibility
# setting...
self.sharex = False
else:
self.sharex = sharex
self.sharey = sharey
self.figsize = figsize
self.layout = layout
self.xticks = xticks
self.yticks = yticks
self.xlim = xlim
self.ylim = ylim
self.title = title
self.use_index = use_index
self.fontsize = fontsize
if rot is not None:
self.rot = rot
# need to know for format_date_labels since it's rotated to 30 by
# default
self._rot_set = True
else:
self._rot_set = False
self.rot = self._default_rot
if grid is None:
grid = False if secondary_y else plt.rcParams["axes.grid"]
self.grid = grid
self.legend = legend
self.legend_handles = []
self.legend_labels = []
for attr in self._pop_attributes:
value = kwds.pop(attr, self._attr_defaults.get(attr, None))
setattr(self, attr, value)
self.ax = ax
self.fig = fig
self.axes = None
# parse errorbar input if given
xerr = kwds.pop("xerr", None)
yerr = kwds.pop("yerr", None)
self.errors = {
kw: self._parse_errorbars(kw, err)
for kw, err in zip(["xerr", "yerr"], [xerr, yerr])
}
if not isinstance(secondary_y, (bool, tuple, list, np.ndarray, ABCIndexClass)):
secondary_y = [secondary_y]
self.secondary_y = secondary_y
# ugly TypeError if user passes matplotlib's `cmap` name.
# Probably better to accept either.
if "cmap" in kwds and colormap:
raise TypeError("Only specify one of `cmap` and `colormap`.")
elif "cmap" in kwds:
self.colormap = kwds.pop("cmap")
else:
self.colormap = colormap
self.table = table
self.include_bool = include_bool
self.kwds = kwds
self._validate_color_args()
def _validate_color_args(self):
if "color" not in self.kwds and "colors" in self.kwds:
warnings.warn(
(
"'colors' is being deprecated. Please use 'color'"
"instead of 'colors'"
)
)
colors = self.kwds.pop("colors")
self.kwds["color"] = colors
if (
"color" in self.kwds
and self.nseries == 1
and not is_list_like(self.kwds["color"])
):
# support series.plot(color='green')
self.kwds["color"] = [self.kwds["color"]]
if (
"color" in self.kwds
and isinstance(self.kwds["color"], tuple)
and self.nseries == 1
and len(self.kwds["color"]) in (3, 4)
):
# support RGB and RGBA tuples in series plot
self.kwds["color"] = [self.kwds["color"]]
if (
"color" in self.kwds or "colors" in self.kwds
) and self.colormap is not None:
warnings.warn(
"'color' and 'colormap' cannot be used " "simultaneously. Using 'color'"
)
if "color" in self.kwds and self.style is not None:
if is_list_like(self.style):
styles = self.style
else:
styles = [self.style]
# need only a single match
for s in styles:
if re.match("^[a-z]+?", s) is not None:
raise ValueError(
"Cannot pass 'style' string with a color "
"symbol and 'color' keyword argument. Please"
" use one or the other or pass 'style' "
"without a color symbol"
)
def _iter_data(self, data=None, keep_index=False, fillna=None):
if data is None:
data = self.data
if fillna is not None:
data = data.fillna(fillna)
# TODO: unused?
# if self.sort_columns:
# columns = com.try_sort(data.columns)
# else:
# columns = data.columns
for col, values in data.items():
if keep_index is True:
yield col, values
else:
yield col, values.values
@property
def nseries(self):
if self.data.ndim == 1:
return 1
else:
return self.data.shape[1]
def draw(self):
self.plt.draw_if_interactive()
def generate(self):
self._args_adjust()
self._compute_plot_data()
self._setup_subplots()
self._make_plot()
self._add_table()
self._make_legend()
self._adorn_subplots()
for ax in self.axes:
self._post_plot_logic_common(ax, self.data)
self._post_plot_logic(ax, self.data)
def _args_adjust(self):
pass
def _has_plotted_object(self, ax):
"""check whether ax has data"""
return len(ax.lines) != 0 or len(ax.artists) != 0 or len(ax.containers) != 0
def _maybe_right_yaxis(self, ax, axes_num):
if not self.on_right(axes_num):
# secondary axes may be passed via ax kw
return self._get_ax_layer(ax)
if hasattr(ax, "right_ax"):
# if it has right_ax proparty, ``ax`` must be left axes
return ax.right_ax
elif hasattr(ax, "left_ax"):
# if it has left_ax proparty, ``ax`` must be right axes
return ax
else:
# otherwise, create twin axes
orig_ax, new_ax = ax, ax.twinx()
# TODO: use Matplotlib public API when available
new_ax._get_lines = orig_ax._get_lines
new_ax._get_patches_for_fill = orig_ax._get_patches_for_fill
orig_ax.right_ax, new_ax.left_ax = new_ax, orig_ax
if not self._has_plotted_object(orig_ax): # no data on left y
orig_ax.get_yaxis().set_visible(False)
if self.logy is True or self.loglog is True:
new_ax.set_yscale("log")
elif self.logy == "sym" or self.loglog == "sym":
new_ax.set_yscale("symlog")
return new_ax
def _setup_subplots(self):
if self.subplots:
fig, axes = _subplots(
naxes=self.nseries,
sharex=self.sharex,
sharey=self.sharey,
figsize=self.figsize,
ax=self.ax,
layout=self.layout,
layout_type=self._layout_type,
)
else:
if self.ax is None:
fig = self.plt.figure(figsize=self.figsize)
axes = fig.add_subplot(111)
else:
fig = self.ax.get_figure()
if self.figsize is not None:
fig.set_size_inches(self.figsize)
axes = self.ax
axes = _flatten(axes)
valid_log = {False, True, "sym", None}
input_log = {self.logx, self.logy, self.loglog}
if input_log - valid_log:
invalid_log = next(iter((input_log - valid_log)))
raise ValueError(
"Boolean, None and 'sym' are valid options,"
" '{}' is given.".format(invalid_log)
)
if self.logx is True or self.loglog is True:
[a.set_xscale("log") for a in axes]
elif self.logx == "sym" or self.loglog == "sym":
[a.set_xscale("symlog") for a in axes]
if self.logy is True or self.loglog is True:
[a.set_yscale("log") for a in axes]
elif self.logy == "sym" or self.loglog == "sym":
[a.set_yscale("symlog") for a in axes]
self.fig = fig
self.axes = axes
@property
def result(self):
"""
Return result axes
"""
if self.subplots:
if self.layout is not None and not is_list_like(self.ax):
return self.axes.reshape(*self.layout)
else:
return self.axes
else:
sec_true = isinstance(self.secondary_y, bool) and self.secondary_y
all_sec = (
is_list_like(self.secondary_y) and len(self.secondary_y) == self.nseries
)
if sec_true or all_sec:
# if all data is plotted on secondary, return right axes
return self._get_ax_layer(self.axes[0], primary=False)
else:
return self.axes[0]
def _compute_plot_data(self):
data = self.data
if isinstance(data, ABCSeries):
label = self.label
if label is None and data.name is None:
label = "None"
data = data.to_frame(name=label)
# GH16953, _convert is needed as fallback, for ``Series``
# with ``dtype == object``
data = data._convert(datetime=True, timedelta=True)
include_type = [np.number, "datetime", "datetimetz", "timedelta"]
# GH23719, allow plotting boolean
if self.include_bool is True:
include_type.append(np.bool_)
# GH22799, exclude datatime-like type for boxplot
exclude_type = None
if self._kind == "box":
# TODO: change after solving issue 27881
include_type = [np.number]
exclude_type = ["timedelta"]
numeric_data = data.select_dtypes(include=include_type, exclude=exclude_type)
try:
is_empty = numeric_data.columns.empty
except AttributeError:
is_empty = not len(numeric_data)
# no non-numeric frames or series allowed
if is_empty:
raise TypeError("no numeric data to plot")
# GH25587: cast ExtensionArray of pandas (IntegerArray, etc.) to
# np.ndarray before plot.
numeric_data = numeric_data.copy()
for col in numeric_data:
numeric_data[col] = np.asarray(numeric_data[col])
self.data = numeric_data
def _make_plot(self):
raise AbstractMethodError(self)
def _add_table(self):
if self.table is False:
return
elif self.table is True:
data = self.data.transpose()
else:
data = self.table
ax = self._get_ax(0)
table(ax, data)
def _post_plot_logic_common(self, ax, data):
"""Common post process for each axes"""
if self.orientation == "vertical" or self.orientation is None:
self._apply_axis_properties(ax.xaxis, rot=self.rot, fontsize=self.fontsize)
self._apply_axis_properties(ax.yaxis, fontsize=self.fontsize)
if hasattr(ax, "right_ax"):
self._apply_axis_properties(ax.right_ax.yaxis, fontsize=self.fontsize)
elif self.orientation == "horizontal":
self._apply_axis_properties(ax.yaxis, rot=self.rot, fontsize=self.fontsize)
self._apply_axis_properties(ax.xaxis, fontsize=self.fontsize)
if hasattr(ax, "right_ax"):
self._apply_axis_properties(ax.right_ax.yaxis, fontsize=self.fontsize)
else: # pragma no cover
raise ValueError
def _post_plot_logic(self, ax, data):
"""Post process for each axes. Overridden in child classes"""
pass
def _adorn_subplots(self):
"""Common post process unrelated to data"""
if len(self.axes) > 0:
all_axes = self._get_subplots()
nrows, ncols = self._get_axes_layout()
_handle_shared_axes(
axarr=all_axes,
nplots=len(all_axes),
naxes=nrows * ncols,
nrows=nrows,
ncols=ncols,
sharex=self.sharex,
sharey=self.sharey,
)
for ax in self.axes:
if self.yticks is not None:
ax.set_yticks(self.yticks)
if self.xticks is not None:
ax.set_xticks(self.xticks)
if self.ylim is not None:
ax.set_ylim(self.ylim)
if self.xlim is not None:
ax.set_xlim(self.xlim)
ax.grid(self.grid)
if self.title:
if self.subplots:
if is_list_like(self.title):
if len(self.title) != self.nseries:
msg = (
"The length of `title` must equal the number "
"of columns if using `title` of type `list` "
"and `subplots=True`.\n"
"length of title = {}\n"
"number of columns = {}"
).format(len(self.title), self.nseries)
raise ValueError(msg)
for (ax, title) in zip(self.axes, self.title):
ax.set_title(title)
else:
self.fig.suptitle(self.title)
else:
if is_list_like(self.title):
msg = (
"Using `title` of type `list` is not supported "
"unless `subplots=True` is passed"
)
raise ValueError(msg)
self.axes[0].set_title(self.title)
def _apply_axis_properties(self, axis, rot=None, fontsize=None):
""" Tick creation within matplotlib is reasonably expensive and is
internally deferred until accessed as Ticks are created/destroyed
multiple times per draw. It's therefore beneficial for us to avoid
accessing unless we will act on the Tick.
"""
if rot is not None or fontsize is not None:
# rot=0 is a valid setting, hence the explicit None check
labels = axis.get_majorticklabels() + axis.get_minorticklabels()
for label in labels:
if rot is not None:
label.set_rotation(rot)
if fontsize is not None:
label.set_fontsize(fontsize)
@property
def legend_title(self):
if not isinstance(self.data.columns, ABCMultiIndex):
name = self.data.columns.name
if name is not None:
name = pprint_thing(name)
return name
else:
stringified = map(pprint_thing, self.data.columns.names)
return ",".join(stringified)
def _add_legend_handle(self, handle, label, index=None):
if label is not None:
if self.mark_right and index is not None:
if self.on_right(index):
label = label + " (right)"
self.legend_handles.append(handle)
self.legend_labels.append(label)
def _make_legend(self):
ax, leg, handle = self._get_ax_legend_handle(self.axes[0])
handles = []
labels = []
title = ""
if not self.subplots:
if leg is not None:
title = leg.get_title().get_text()
# Replace leg.LegendHandles because it misses marker info
handles.extend(handle)
labels = [x.get_text() for x in leg.get_texts()]
if self.legend:
if self.legend == "reverse":
self.legend_handles = reversed(self.legend_handles)
self.legend_labels = reversed(self.legend_labels)
handles += self.legend_handles
labels += self.legend_labels
if self.legend_title is not None:
title = self.legend_title
if len(handles) > 0:
ax.legend(handles, labels, loc="best", title=title)
elif self.subplots and self.legend:
for ax in self.axes:
if ax.get_visible():
ax.legend(loc="best")
def _get_ax_legend_handle(self, ax):
"""
Take in axes and return ax, legend and handle under different scenarios
"""
leg = ax.get_legend()
# Get handle from axes
handle, _ = ax.get_legend_handles_labels()
other_ax = getattr(ax, "left_ax", None) or getattr(ax, "right_ax", None)
other_leg = None
if other_ax is not None:
other_leg = other_ax.get_legend()
if leg is None and other_leg is not None:
leg = other_leg
ax = other_ax
return ax, leg, handle
@cache_readonly
def plt(self):
import matplotlib.pyplot as plt
return plt
_need_to_set_index = False
def _get_xticks(self, convert_period=False):
index = self.data.index
is_datetype = index.inferred_type in ("datetime", "date", "datetime64", "time")
if self.use_index:
if convert_period and isinstance(index, ABCPeriodIndex):
self.data = self.data.reindex(index=index.sort_values())
x = self.data.index.to_timestamp()._mpl_repr()
elif index.is_numeric():
"""
Matplotlib supports numeric values or datetime objects as
xaxis values. Taking LBYL approach here, by the time
matplotlib raises exception when using non numeric/datetime
values for xaxis, several actions are already taken by plt.
"""
x = index._mpl_repr()
elif is_datetype:
self.data = self.data[notna(self.data.index)]
self.data = self.data.sort_index()
x = self.data.index._mpl_repr()
else:
self._need_to_set_index = True
x = list(range(len(index)))
else:
x = list(range(len(index)))
return x
@classmethod
def _plot(cls, ax, x, y, style=None, is_errorbar=False, **kwds):
mask = isna(y)
if mask.any():
y = np.ma.array(y)
y = np.ma.masked_where(mask, y)
if isinstance(x, ABCIndexClass):
x = x._mpl_repr()
if is_errorbar:
if "xerr" in kwds:
kwds["xerr"] = np.array(kwds.get("xerr"))
if "yerr" in kwds:
kwds["yerr"] = np.array(kwds.get("yerr"))
return ax.errorbar(x, y, **kwds)
else:
# prevent style kwarg from going to errorbar, where it is
# unsupported
if style is not None:
args = (x, y, style)
else:
args = (x, y)
return ax.plot(*args, **kwds)
def _get_index_name(self):
if isinstance(self.data.index, ABCMultiIndex):
name = self.data.index.names
if com.any_not_none(*name):
name = ",".join(pprint_thing(x) for x in name)
else:
name = None
else:
name = self.data.index.name
if name is not None:
name = pprint_thing(name)
return name
@classmethod
def _get_ax_layer(cls, ax, primary=True):
"""get left (primary) or right (secondary) axes"""
if primary:
return getattr(ax, "left_ax", ax)
else:
return getattr(ax, "right_ax", ax)
def _get_ax(self, i):
# get the twinx ax if appropriate
if self.subplots:
ax = self.axes[i]
ax = self._maybe_right_yaxis(ax, i)
self.axes[i] = ax
else:
ax = self.axes[0]
ax = self._maybe_right_yaxis(ax, i)
ax.get_yaxis().set_visible(True)
return ax
@classmethod
def get_default_ax(cls, ax):
import matplotlib.pyplot as plt
if ax is None and len(plt.get_fignums()) > 0:
with plt.rc_context():
ax = plt.gca()
ax = cls._get_ax_layer(ax)
def on_right(self, i):
if isinstance(self.secondary_y, bool):
return self.secondary_y
if isinstance(self.secondary_y, (tuple, list, np.ndarray, ABCIndexClass)):
return self.data.columns[i] in self.secondary_y
def _apply_style_colors(self, colors, kwds, col_num, label):
"""
Manage style and color based on column number and its label.
Returns tuple of appropriate style and kwds which "color" may be added.
"""
style = None
if self.style is not None:
if isinstance(self.style, list):
try:
style = self.style[col_num]
except IndexError:
pass
elif isinstance(self.style, dict):
style = self.style.get(label, style)
else:
style = self.style
has_color = "color" in kwds or self.colormap is not None
nocolor_style = style is None or re.match("[a-z]+", style) is None
if (has_color or self.subplots) and nocolor_style:
kwds["color"] = colors[col_num % len(colors)]
return style, kwds
def _get_colors(self, num_colors=None, color_kwds="color"):
if num_colors is None:
num_colors = self.nseries
return _get_standard_colors(
num_colors=num_colors,
colormap=self.colormap,
color=self.kwds.get(color_kwds),
)
def _parse_errorbars(self, label, err):
"""
Look for error keyword arguments and return the actual errorbar data
or return the error DataFrame/dict
Error bars can be specified in several ways:
Series: the user provides a pandas.Series object of the same
length as the data
ndarray: provides a np.ndarray of the same length as the data
DataFrame/dict: error values are paired with keys matching the
key in the plotted DataFrame
str: the name of the column within the plotted DataFrame
"""
if err is None:
return None
def match_labels(data, e):
e = e.reindex(data.index)
return e
# key-matched DataFrame
if isinstance(err, ABCDataFrame):
err = match_labels(self.data, err)
# key-matched dict
elif isinstance(err, dict):
pass
# Series of error values
elif isinstance(err, ABCSeries):
# broadcast error series across data
err = match_labels(self.data, err)
err = np.atleast_2d(err)
err = np.tile(err, (self.nseries, 1))
# errors are a column in the dataframe
elif isinstance(err, str):
evalues = self.data[err].values
self.data = self.data[self.data.columns.drop(err)]
err = np.atleast_2d(evalues)
err = np.tile(err, (self.nseries, 1))
elif is_list_like(err):
if is_iterator(err):
err = np.atleast_2d(list(err))
else:
# raw error values
err = np.atleast_2d(err)
err_shape = err.shape
# asymmetrical error bars
if err.ndim == 3:
if (
(err_shape[0] != self.nseries)
or (err_shape[1] != 2)
or (err_shape[2] != len(self.data))
):
msg = (
"Asymmetrical error bars should be provided "
+ "with the shape (%u, 2, %u)" % (self.nseries, len(self.data))
)
raise ValueError(msg)
# broadcast errors to each data series
if len(err) == 1:
err = np.tile(err, (self.nseries, 1))
elif is_number(err):
err = np.tile([err], (self.nseries, len(self.data)))
else:
msg = "No valid {label} detected".format(label=label)
raise ValueError(msg)
return err
def _get_errorbars(self, label=None, index=None, xerr=True, yerr=True):
errors = {}
for kw, flag in zip(["xerr", "yerr"], [xerr, yerr]):
if flag:
err = self.errors[kw]
# user provided label-matched dataframe of errors
if isinstance(err, (ABCDataFrame, dict)):
if label is not None and label in err.keys():
err = err[label]
else:
err = None
elif index is not None and err is not None:
err = err[index]
if err is not None:
errors[kw] = err
return errors
def _get_subplots(self):
from matplotlib.axes import Subplot
return [
ax for ax in self.axes[0].get_figure().get_axes() if isinstance(ax, Subplot)
]
def _get_axes_layout(self):
axes = self._get_subplots()
x_set = set()
y_set = set()
for ax in axes:
# check axes coordinates to estimate layout
points = ax.get_position().get_points()
x_set.add(points[0][0])
y_set.add(points[0][1])
return (len(y_set), len(x_set))
class PlanePlot(MPLPlot):
"""
Abstract class for plotting on plane, currently scatter and hexbin.
"""
_layout_type = "single"
def __init__(self, data, x, y, **kwargs):
MPLPlot.__init__(self, data, **kwargs)
if x is None or y is None:
raise ValueError(self._kind + " requires an x and y column")
if is_integer(x) and not self.data.columns.holds_integer():
x = self.data.columns[x]
if is_integer(y) and not self.data.columns.holds_integer():
y = self.data.columns[y]
if len(self.data[x]._get_numeric_data()) == 0:
raise ValueError(self._kind + " requires x column to be numeric")
if len(self.data[y]._get_numeric_data()) == 0:
raise ValueError(self._kind + " requires y column to be numeric")
self.x = x
self.y = y
@property
def nseries(self):
return 1
def _post_plot_logic(self, ax, data):
x, y = self.x, self.y
ax.set_ylabel(pprint_thing(y))
ax.set_xlabel(pprint_thing(x))
def _plot_colorbar(self, ax, **kwds):
# Addresses issues #10611 and #10678:
# When plotting scatterplots and hexbinplots in IPython
# inline backend the colorbar axis height tends not to
# exactly match the parent axis height.
# The difference is due to small fractional differences
# in floating points with similar representation.
# To deal with this, this method forces the colorbar
# height to take the height of the parent axes.
# For a more detailed description of the issue
# see the following link:
# https://github.com/ipython/ipython/issues/11215
img = ax.collections[0]
cbar = self.fig.colorbar(img, ax=ax, **kwds)
if _mpl_ge_3_0_0():
# The workaround below is no longer necessary.
return
points = ax.get_position().get_points()
cbar_points = cbar.ax.get_position().get_points()
cbar.ax.set_position(
[
cbar_points[0, 0],
points[0, 1],
cbar_points[1, 0] - cbar_points[0, 0],
points[1, 1] - points[0, 1],
]
)
# To see the discrepancy in axis heights uncomment
# the following two lines:
# print(points[1, 1] - points[0, 1])
# print(cbar_points[1, 1] - cbar_points[0, 1])
class ScatterPlot(PlanePlot):
_kind = "scatter"
def __init__(self, data, x, y, s=None, c=None, **kwargs):
if s is None:
# hide the matplotlib default for size, in case we want to change
# the handling of this argument later
s = 20
super().__init__(data, x, y, s=s, **kwargs)
if is_integer(c) and not self.data.columns.holds_integer():
c = self.data.columns[c]
self.c = c
def _make_plot(self):
x, y, c, data = self.x, self.y, self.c, self.data
ax = self.axes[0]
c_is_column = is_hashable(c) and c in self.data.columns
# plot a colorbar only if a colormap is provided or necessary
cb = self.kwds.pop("colorbar", self.colormap or c_is_column)
# pandas uses colormap, matplotlib uses cmap.
cmap = self.colormap or "Greys"
cmap = self.plt.cm.get_cmap(cmap)
color = self.kwds.pop("color", None)
if c is not None and color is not None:
raise TypeError("Specify exactly one of `c` and `color`")
elif c is None and color is None:
c_values = self.plt.rcParams["patch.facecolor"]
elif color is not None:
c_values = color
elif c_is_column:
c_values = self.data[c].values
else:
c_values = c
if self.legend and hasattr(self, "label"):
label = self.label
else:
label = None
scatter = ax.scatter(
data[x].values,
data[y].values,
c=c_values,
label=label,
cmap=cmap,
**self.kwds
)
if cb:
cbar_label = c if c_is_column else ""
self._plot_colorbar(ax, label=cbar_label)
if label is not None:
self._add_legend_handle(scatter, label)
else:
self.legend = False
errors_x = self._get_errorbars(label=x, index=0, yerr=False)
errors_y = self._get_errorbars(label=y, index=0, xerr=False)
if len(errors_x) > 0 or len(errors_y) > 0:
err_kwds = dict(errors_x, **errors_y)
err_kwds["ecolor"] = scatter.get_facecolor()[0]
ax.errorbar(data[x].values, data[y].values, linestyle="none", **err_kwds)
class HexBinPlot(PlanePlot):
_kind = "hexbin"
def __init__(self, data, x, y, C=None, **kwargs):
super().__init__(data, x, y, **kwargs)
if is_integer(C) and not self.data.columns.holds_integer():
C = self.data.columns[C]
self.C = C
def _make_plot(self):
x, y, data, C = self.x, self.y, self.data, self.C
ax = self.axes[0]
# pandas uses colormap, matplotlib uses cmap.
cmap = self.colormap or "BuGn"
cmap = self.plt.cm.get_cmap(cmap)
cb = self.kwds.pop("colorbar", True)
if C is None:
c_values = None
else:
c_values = data[C].values
ax.hexbin(data[x].values, data[y].values, C=c_values, cmap=cmap, **self.kwds)
if cb:
self._plot_colorbar(ax)
def _make_legend(self):
pass
class LinePlot(MPLPlot):
_kind = "line"
_default_rot = 0
orientation = "vertical"
def __init__(self, data, **kwargs):
from pandas.plotting import plot_params
MPLPlot.__init__(self, data, **kwargs)
if self.stacked:
self.data = self.data.fillna(value=0)
self.x_compat = plot_params["x_compat"]
if "x_compat" in self.kwds:
self.x_compat = bool(self.kwds.pop("x_compat"))
def _is_ts_plot(self):
# this is slightly deceptive
return not self.x_compat and self.use_index and self._use_dynamic_x()
def _use_dynamic_x(self):
from pandas.plotting._matplotlib.timeseries import _use_dynamic_x
return _use_dynamic_x(self._get_ax(0), self.data)
def _make_plot(self):
if self._is_ts_plot():
from pandas.plotting._matplotlib.timeseries import _maybe_convert_index
data = _maybe_convert_index(self._get_ax(0), self.data)
x = data.index # dummy, not used
plotf = self._ts_plot
it = self._iter_data(data=data, keep_index=True)
else:
x = self._get_xticks(convert_period=True)
plotf = self._plot
it = self._iter_data()
stacking_id = self._get_stacking_id()
is_errorbar = com.any_not_none(*self.errors.values())
colors = self._get_colors()
for i, (label, y) in enumerate(it):
ax = self._get_ax(i)
kwds = self.kwds.copy()
style, kwds = self._apply_style_colors(colors, kwds, i, label)
errors = self._get_errorbars(label=label, index=i)
kwds = dict(kwds, **errors)
label = pprint_thing(label) # .encode('utf-8')
kwds["label"] = label
newlines = plotf(
ax,
x,
y,
style=style,
column_num=i,
stacking_id=stacking_id,
is_errorbar=is_errorbar,
**kwds
)
self._add_legend_handle(newlines[0], label, index=i)
if self._is_ts_plot():
# reset of xlim should be used for ts data
# TODO: GH28021, should find a way to change view limit on xaxis
lines = _get_all_lines(ax)
left, right = _get_xlim(lines)
ax.set_xlim(left, right)
@classmethod
def _plot(cls, ax, x, y, style=None, column_num=None, stacking_id=None, **kwds):
# column_num is used to get the target column from protf in line and
# area plots
if column_num == 0:
cls._initialize_stacker(ax, stacking_id, len(y))
y_values = cls._get_stacked_values(ax, stacking_id, y, kwds["label"])
lines = MPLPlot._plot(ax, x, y_values, style=style, **kwds)
cls._update_stacker(ax, stacking_id, y)
return lines
@classmethod
def _ts_plot(cls, ax, x, data, style=None, **kwds):
from pandas.plotting._matplotlib.timeseries import (
_maybe_resample,
_decorate_axes,
format_dateaxis,
)
# accept x to be consistent with normal plot func,
# x is not passed to tsplot as it uses data.index as x coordinate
# column_num must be in kwds for stacking purpose
freq, data = _maybe_resample(data, ax, kwds)
# Set ax with freq info
_decorate_axes(ax, freq, kwds)
# digging deeper
if hasattr(ax, "left_ax"):
_decorate_axes(ax.left_ax, freq, kwds)
if hasattr(ax, "right_ax"):
_decorate_axes(ax.right_ax, freq, kwds)
ax._plot_data.append((data, cls._kind, kwds))
lines = cls._plot(ax, data.index, data.values, style=style, **kwds)
# set date formatter, locators and rescale limits
format_dateaxis(ax, ax.freq, data.index)
return lines
def _get_stacking_id(self):
if self.stacked:
return id(self.data)
else:
return None
@classmethod
def _initialize_stacker(cls, ax, stacking_id, n):
if stacking_id is None:
return
if not hasattr(ax, "_stacker_pos_prior"):
ax._stacker_pos_prior = {}
if not hasattr(ax, "_stacker_neg_prior"):
ax._stacker_neg_prior = {}
ax._stacker_pos_prior[stacking_id] = np.zeros(n)
ax._stacker_neg_prior[stacking_id] = np.zeros(n)
@classmethod
def _get_stacked_values(cls, ax, stacking_id, values, label):
if stacking_id is None:
return values
if not hasattr(ax, "_stacker_pos_prior"):
# stacker may not be initialized for subplots
cls._initialize_stacker(ax, stacking_id, len(values))
if (values >= 0).all():
return ax._stacker_pos_prior[stacking_id] + values
elif (values <= 0).all():
return ax._stacker_neg_prior[stacking_id] + values
raise ValueError(
"When stacked is True, each column must be either "
"all positive or negative."
"{0} contains both positive and negative values".format(label)
)
@classmethod
def _update_stacker(cls, ax, stacking_id, values):
if stacking_id is None:
return
if (values >= 0).all():
ax._stacker_pos_prior[stacking_id] += values
elif (values <= 0).all():
ax._stacker_neg_prior[stacking_id] += values
def _post_plot_logic(self, ax, data):
from matplotlib.ticker import FixedLocator
def get_label(i):
try:
return pprint_thing(data.index[i])
except Exception:
return ""
if self._need_to_set_index:
xticks = ax.get_xticks()
xticklabels = [get_label(x) for x in xticks]
ax.set_xticklabels(xticklabels)
ax.xaxis.set_major_locator(FixedLocator(xticks))
condition = (
not self._use_dynamic_x()
and data.index.is_all_dates
and not self.subplots
or (self.subplots and self.sharex)
)
index_name = self._get_index_name()
if condition:
# irregular TS rotated 30 deg. by default
# probably a better place to check / set this.
if not self._rot_set:
self.rot = 30
format_date_labels(ax, rot=self.rot)
if index_name is not None and self.use_index:
ax.set_xlabel(index_name)
class AreaPlot(LinePlot):
_kind = "area"
def __init__(self, data, **kwargs):
kwargs.setdefault("stacked", True)
data = data.fillna(value=0)
LinePlot.__init__(self, data, **kwargs)
if not self.stacked:
# use smaller alpha to distinguish overlap
self.kwds.setdefault("alpha", 0.5)
if self.logy or self.loglog:
raise ValueError("Log-y scales are not supported in area plot")
@classmethod
def _plot(
cls,
ax,
x,
y,
style=None,
column_num=None,
stacking_id=None,
is_errorbar=False,
**kwds
):
if column_num == 0:
cls._initialize_stacker(ax, stacking_id, len(y))
y_values = cls._get_stacked_values(ax, stacking_id, y, kwds["label"])
# need to remove label, because subplots uses mpl legend as it is
line_kwds = kwds.copy()
line_kwds.pop("label")
lines = MPLPlot._plot(ax, x, y_values, style=style, **line_kwds)
# get data from the line to get coordinates for fill_between
xdata, y_values = lines[0].get_data(orig=False)
# unable to use ``_get_stacked_values`` here to get starting point
if stacking_id is None:
start = np.zeros(len(y))
elif (y >= 0).all():
start = ax._stacker_pos_prior[stacking_id]
elif (y <= 0).all():
start = ax._stacker_neg_prior[stacking_id]
else:
start = np.zeros(len(y))
if "color" not in kwds:
kwds["color"] = lines[0].get_color()
rect = ax.fill_between(xdata, start, y_values, **kwds)
cls._update_stacker(ax, stacking_id, y)
# LinePlot expects list of artists
res = [rect]
return res
def _post_plot_logic(self, ax, data):
LinePlot._post_plot_logic(self, ax, data)
if self.ylim is None:
if (data >= 0).all().all():
ax.set_ylim(0, None)
elif (data <= 0).all().all():
ax.set_ylim(None, 0)
class BarPlot(MPLPlot):
_kind = "bar"
_default_rot = 90
orientation = "vertical"
def __init__(self, data, **kwargs):
# we have to treat a series differently than a
# 1-column DataFrame w.r.t. color handling
self._is_series = isinstance(data, ABCSeries)
self.bar_width = kwargs.pop("width", 0.5)
pos = kwargs.pop("position", 0.5)
kwargs.setdefault("align", "center")
self.tick_pos = np.arange(len(data))
self.bottom = kwargs.pop("bottom", 0)
self.left = kwargs.pop("left", 0)
self.log = kwargs.pop("log", False)
MPLPlot.__init__(self, data, **kwargs)
if self.stacked or self.subplots:
self.tickoffset = self.bar_width * pos
if kwargs["align"] == "edge":
self.lim_offset = self.bar_width / 2
else:
self.lim_offset = 0
else:
if kwargs["align"] == "edge":
w = self.bar_width / self.nseries
self.tickoffset = self.bar_width * (pos - 0.5) + w * 0.5
self.lim_offset = w * 0.5
else:
self.tickoffset = self.bar_width * pos
self.lim_offset = 0
self.ax_pos = self.tick_pos - self.tickoffset
def _args_adjust(self):
if is_list_like(self.bottom):
self.bottom = np.array(self.bottom)
if is_list_like(self.left):
self.left = np.array(self.left)
@classmethod
def _plot(cls, ax, x, y, w, start=0, log=False, **kwds):
return ax.bar(x, y, w, bottom=start, log=log, **kwds)
@property
def _start_base(self):
return self.bottom
def _make_plot(self):
import matplotlib as mpl
colors = self._get_colors()
ncolors = len(colors)
pos_prior = neg_prior = np.zeros(len(self.data))
K = self.nseries
for i, (label, y) in enumerate(self._iter_data(fillna=0)):
ax = self._get_ax(i)
kwds = self.kwds.copy()
if self._is_series:
kwds["color"] = colors
else:
kwds["color"] = colors[i % ncolors]
errors = self._get_errorbars(label=label, index=i)
kwds = dict(kwds, **errors)
label = pprint_thing(label)
if (("yerr" in kwds) or ("xerr" in kwds)) and (kwds.get("ecolor") is None):
kwds["ecolor"] = mpl.rcParams["xtick.color"]
start = 0
if self.log and (y >= 1).all():
start = 1
start = start + self._start_base
if self.subplots:
w = self.bar_width / 2
rect = self._plot(
ax,
self.ax_pos + w,
y,
self.bar_width,
start=start,
label=label,
log=self.log,
**kwds
)
ax.set_title(label)
elif self.stacked:
mask = y > 0
start = np.where(mask, pos_prior, neg_prior) + self._start_base
w = self.bar_width / 2
rect = self._plot(
ax,
self.ax_pos + w,
y,
self.bar_width,
start=start,
label=label,
log=self.log,
**kwds
)
pos_prior = pos_prior + np.where(mask, y, 0)
neg_prior = neg_prior + np.where(mask, 0, y)
else:
w = self.bar_width / K
rect = self._plot(
ax,
self.ax_pos + (i + 0.5) * w,
y,
w,
start=start,
label=label,
log=self.log,
**kwds
)
self._add_legend_handle(rect, label, index=i)
def _post_plot_logic(self, ax, data):
if self.use_index:
str_index = [pprint_thing(key) for key in data.index]
else:
str_index = [pprint_thing(key) for key in range(data.shape[0])]
name = self._get_index_name()
s_edge = self.ax_pos[0] - 0.25 + self.lim_offset
e_edge = self.ax_pos[-1] + 0.25 + self.bar_width + self.lim_offset
self._decorate_ticks(ax, name, str_index, s_edge, e_edge)
def _decorate_ticks(self, ax, name, ticklabels, start_edge, end_edge):
ax.set_xlim((start_edge, end_edge))
if self.xticks is not None:
ax.set_xticks(np.array(self.xticks))
else:
ax.set_xticks(self.tick_pos)
ax.set_xticklabels(ticklabels)
if name is not None and self.use_index:
ax.set_xlabel(name)
class BarhPlot(BarPlot):
_kind = "barh"
_default_rot = 0
orientation = "horizontal"
@property
def _start_base(self):
return self.left
@classmethod
def _plot(cls, ax, x, y, w, start=0, log=False, **kwds):
return ax.barh(x, y, w, left=start, log=log, **kwds)
def _decorate_ticks(self, ax, name, ticklabels, start_edge, end_edge):
# horizontal bars
ax.set_ylim((start_edge, end_edge))
ax.set_yticks(self.tick_pos)
ax.set_yticklabels(ticklabels)
if name is not None and self.use_index:
ax.set_ylabel(name)
class PiePlot(MPLPlot):
_kind = "pie"
_layout_type = "horizontal"
def __init__(self, data, kind=None, **kwargs):
data = data.fillna(value=0)
if (data < 0).any().any():
raise ValueError("{0} doesn't allow negative values".format(kind))
MPLPlot.__init__(self, data, kind=kind, **kwargs)
def _args_adjust(self):
self.grid = False
self.logy = False
self.logx = False
self.loglog = False
def _validate_color_args(self):
pass
def _make_plot(self):
colors = self._get_colors(num_colors=len(self.data), color_kwds="colors")
self.kwds.setdefault("colors", colors)
for i, (label, y) in enumerate(self._iter_data()):
ax = self._get_ax(i)
if label is not None:
label = pprint_thing(label)
ax.set_ylabel(label)
kwds = self.kwds.copy()
def blank_labeler(label, value):
if value == 0:
return ""
else:
return label
idx = [pprint_thing(v) for v in self.data.index]
labels = kwds.pop("labels", idx)
# labels is used for each wedge's labels
# Blank out labels for values of 0 so they don't overlap
# with nonzero wedges
if labels is not None:
blabels = [blank_labeler(l, value) for l, value in zip(labels, y)]
else:
blabels = None
results = ax.pie(y, labels=blabels, **kwds)
if kwds.get("autopct", None) is not None:
patches, texts, autotexts = results
else:
patches, texts = results
autotexts = []
if self.fontsize is not None:
for t in texts + autotexts:
t.set_fontsize(self.fontsize)
# leglabels is used for legend labels
leglabels = labels if labels is not None else idx
for p, l in zip(patches, leglabels):
self._add_legend_handle(p, l)
| BugsInPy/BugsInPy/temp/projects/pandas/bug-144-fixed/pandas/pandas/plotting/_matplotlib/core.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-144-buggy/pandas/pandas/plotting/_matplotlib/core.py |
pandas-bug-79 | """
Provide user facing operators for doing the split part of the
split-apply-combine paradigm.
"""
from typing import Dict, Hashable, List, Optional, Tuple
import numpy as np
from pandas._typing import FrameOrSeries
from pandas.util._decorators import cache_readonly
from pandas.core.dtypes.common import (
ensure_categorical,
is_categorical_dtype,
is_datetime64_dtype,
is_list_like,
is_scalar,
is_timedelta64_dtype,
)
from pandas.core.dtypes.generic import ABCSeries
import pandas.core.algorithms as algorithms
from pandas.core.arrays import Categorical, ExtensionArray
import pandas.core.common as com
from pandas.core.frame import DataFrame
from pandas.core.groupby import ops
from pandas.core.groupby.categorical import recode_for_groupby, recode_from_groupby
from pandas.core.indexes.api import CategoricalIndex, Index, MultiIndex
from pandas.core.series import Series
from pandas.io.formats.printing import pprint_thing
class Grouper:
"""
A Grouper allows the user to specify a groupby instruction for an object.
This specification will select a column via the key parameter, or if the
level and/or axis parameters are given, a level of the index of the target
object.
If `axis` and/or `level` are passed as keywords to both `Grouper` and
`groupby`, the values passed to `Grouper` take precedence.
Parameters
----------
key : str, defaults to None
Groupby key, which selects the grouping column of the target.
level : name/number, defaults to None
The level for the target index.
freq : str / frequency object, defaults to None
This will groupby the specified frequency if the target selection
(via key or level) is a datetime-like object. For full specification
of available frequencies, please see `here
<https://pandas.pydata.org/pandas-docs/stable/user_guide/timeseries.html#offset-aliases>`_.
axis : str, int, defaults to 0
Number/name of the axis.
sort : bool, default to False
Whether to sort the resulting labels.
closed : {'left' or 'right'}
Closed end of interval. Only when `freq` parameter is passed.
label : {'left' or 'right'}
Interval boundary to use for labeling.
Only when `freq` parameter is passed.
convention : {'start', 'end', 'e', 's'}
If grouper is PeriodIndex and `freq` parameter is passed.
base : int, default 0
Only when `freq` parameter is passed.
loffset : str, DateOffset, timedelta object
Only when `freq` parameter is passed.
Returns
-------
A specification for a groupby instruction
Examples
--------
Syntactic sugar for ``df.groupby('A')``
>>> df.groupby(Grouper(key='A'))
Specify a resample operation on the column 'date'
>>> df.groupby(Grouper(key='date', freq='60s'))
Specify a resample operation on the level 'date' on the columns axis
with a frequency of 60s
>>> df.groupby(Grouper(level='date', freq='60s', axis=1))
"""
_attributes: Tuple[str, ...] = ("key", "level", "freq", "axis", "sort")
def __new__(cls, *args, **kwargs):
if kwargs.get("freq") is not None:
from pandas.core.resample import TimeGrouper
cls = TimeGrouper
return super().__new__(cls)
def __init__(self, key=None, level=None, freq=None, axis=0, sort=False):
self.key = key
self.level = level
self.freq = freq
self.axis = axis
self.sort = sort
self.grouper = None
self.obj = None
self.indexer = None
self.binner = None
self._grouper = None
@property
def ax(self):
return self.grouper
def _get_grouper(self, obj, validate: bool = True):
"""
Parameters
----------
obj : the subject object
validate : boolean, default True
if True, validate the grouper
Returns
-------
a tuple of binner, grouper, obj (possibly sorted)
"""
self._set_grouper(obj)
self.grouper, _, self.obj = get_grouper(
self.obj,
[self.key],
axis=self.axis,
level=self.level,
sort=self.sort,
validate=validate,
)
return self.binner, self.grouper, self.obj
def _set_grouper(self, obj: FrameOrSeries, sort: bool = False):
"""
given an object and the specifications, setup the internal grouper
for this particular specification
Parameters
----------
obj : Series or DataFrame
sort : bool, default False
whether the resulting grouper should be sorted
"""
assert obj is not None
if self.key is not None and self.level is not None:
raise ValueError("The Grouper cannot specify both a key and a level!")
# Keep self.grouper value before overriding
if self._grouper is None:
self._grouper = self.grouper
# the key must be a valid info item
if self.key is not None:
key = self.key
# The 'on' is already defined
if getattr(self.grouper, "name", None) == key and isinstance(
obj, ABCSeries
):
ax = self._grouper.take(obj.index)
else:
if key not in obj._info_axis:
raise KeyError(f"The grouper name {key} is not found")
ax = Index(obj[key], name=key)
else:
ax = obj._get_axis(self.axis)
if self.level is not None:
level = self.level
# if a level is given it must be a mi level or
# equivalent to the axis name
if isinstance(ax, MultiIndex):
level = ax._get_level_number(level)
ax = Index(ax._get_level_values(level), name=ax.names[level])
else:
if level not in (0, ax.name):
raise ValueError(f"The level {level} is not valid")
# possibly sort
if (self.sort or sort) and not ax.is_monotonic:
# use stable sort to support first, last, nth
indexer = self.indexer = ax.argsort(kind="mergesort")
ax = ax.take(indexer)
obj = obj.take(indexer, axis=self.axis)
self.obj = obj
self.grouper = ax
return self.grouper
@property
def groups(self):
return self.grouper.groups
def __repr__(self) -> str:
attrs_list = (
f"{attr_name}={repr(getattr(self, attr_name))}"
for attr_name in self._attributes
if getattr(self, attr_name) is not None
)
attrs = ", ".join(attrs_list)
cls_name = type(self).__name__
return f"{cls_name}({attrs})"
class Grouping:
"""
Holds the grouping information for a single key
Parameters
----------
index : Index
grouper :
obj Union[DataFrame, Series]:
name :
level :
observed : bool, default False
If we are a Categorical, use the observed values
in_axis : if the Grouping is a column in self.obj and hence among
Groupby.exclusions list
Returns
-------
**Attributes**:
* indices : dict of {group -> index_list}
* codes : ndarray, group codes
* group_index : unique groups
* groups : dict of {group -> label_list}
"""
def __init__(
self,
index: Index,
grouper=None,
obj: Optional[FrameOrSeries] = None,
name=None,
level=None,
sort: bool = True,
observed: bool = False,
in_axis: bool = False,
):
self.name = name
self.level = level
self.grouper = _convert_grouper(index, grouper)
self.all_grouper = None
self.index = index
self.sort = sort
self.obj = obj
self.observed = observed
self.in_axis = in_axis
# right place for this?
if isinstance(grouper, (Series, Index)) and name is None:
self.name = grouper.name
if isinstance(grouper, MultiIndex):
self.grouper = grouper.values
# we have a single grouper which may be a myriad of things,
# some of which are dependent on the passing in level
if level is not None:
if not isinstance(level, int):
if level not in index.names:
raise AssertionError(f"Level {level} not in index")
level = index.names.index(level)
if self.name is None:
self.name = index.names[level]
(
self.grouper,
self._codes,
self._group_index,
) = index._get_grouper_for_level(self.grouper, level)
# a passed Grouper like, directly get the grouper in the same way
# as single grouper groupby, use the group_info to get codes
elif isinstance(self.grouper, Grouper):
# get the new grouper; we already have disambiguated
# what key/level refer to exactly, don't need to
# check again as we have by this point converted these
# to an actual value (rather than a pd.Grouper)
_, grouper, _ = self.grouper._get_grouper(self.obj, validate=False)
if self.name is None:
self.name = grouper.result_index.name
self.obj = self.grouper.obj
self.grouper = grouper._get_grouper()
else:
if self.grouper is None and self.name is not None and self.obj is not None:
self.grouper = self.obj[self.name]
elif isinstance(self.grouper, (list, tuple)):
self.grouper = com.asarray_tuplesafe(self.grouper)
# a passed Categorical
elif is_categorical_dtype(self.grouper):
self.grouper, self.all_grouper = recode_for_groupby(
self.grouper, self.sort, observed
)
categories = self.grouper.categories
# we make a CategoricalIndex out of the cat grouper
# preserving the categories / ordered attributes
self._codes = self.grouper.codes
if observed:
codes = algorithms.unique1d(self.grouper.codes)
codes = codes[codes != -1]
if sort or self.grouper.ordered:
codes = np.sort(codes)
else:
codes = np.arange(len(categories))
self._group_index = CategoricalIndex(
Categorical.from_codes(
codes=codes, categories=categories, ordered=self.grouper.ordered
),
name=self.name,
)
# we are done
if isinstance(self.grouper, Grouping):
self.grouper = self.grouper.grouper
# no level passed
elif not isinstance(
self.grouper, (Series, Index, ExtensionArray, np.ndarray)
):
if getattr(self.grouper, "ndim", 1) != 1:
t = self.name or str(type(self.grouper))
raise ValueError(f"Grouper for '{t}' not 1-dimensional")
self.grouper = self.index.map(self.grouper)
if not (
hasattr(self.grouper, "__len__")
and len(self.grouper) == len(self.index)
):
grper = pprint_thing(self.grouper)
errmsg = (
"Grouper result violates len(labels) == "
f"len(data)\nresult: {grper}"
)
self.grouper = None # Try for sanity
raise AssertionError(errmsg)
# if we have a date/time-like grouper, make sure that we have
# Timestamps like
if getattr(self.grouper, "dtype", None) is not None:
if is_datetime64_dtype(self.grouper):
self.grouper = self.grouper.astype("datetime64[ns]")
elif is_timedelta64_dtype(self.grouper):
self.grouper = self.grouper.astype("timedelta64[ns]")
def __repr__(self) -> str:
return f"Grouping({self.name})"
def __iter__(self):
return iter(self.indices)
_codes: Optional[np.ndarray] = None
_group_index: Optional[Index] = None
@property
def ngroups(self) -> int:
return len(self.group_index)
@cache_readonly
def indices(self):
# we have a list of groupers
if isinstance(self.grouper, ops.BaseGrouper):
return self.grouper.indices
values = ensure_categorical(self.grouper)
return values._reverse_indexer()
@property
def codes(self) -> np.ndarray:
if self._codes is None:
self._make_codes()
return self._codes
@cache_readonly
def result_index(self) -> Index:
if self.all_grouper is not None:
return recode_from_groupby(self.all_grouper, self.sort, self.group_index)
return self.group_index
@property
def group_index(self) -> Index:
if self._group_index is None:
self._make_codes()
assert self._group_index is not None
return self._group_index
def _make_codes(self) -> None:
if self._codes is None or self._group_index is None:
# we have a list of groupers
if isinstance(self.grouper, ops.BaseGrouper):
codes = self.grouper.codes_info
uniques = self.grouper.result_index
else:
codes, uniques = algorithms.factorize(self.grouper, sort=self.sort)
uniques = Index(uniques, name=self.name)
self._codes = codes
self._group_index = uniques
@cache_readonly
def groups(self) -> Dict[Hashable, np.ndarray]:
return self.index.groupby(Categorical.from_codes(self.codes, self.group_index))
def get_grouper(
obj: FrameOrSeries,
key=None,
axis: int = 0,
level=None,
sort: bool = True,
observed: bool = False,
mutated: bool = False,
validate: bool = True,
) -> "Tuple[ops.BaseGrouper, List[Hashable], FrameOrSeries]":
"""
Create and return a BaseGrouper, which is an internal
mapping of how to create the grouper indexers.
This may be composed of multiple Grouping objects, indicating
multiple groupers
Groupers are ultimately index mappings. They can originate as:
index mappings, keys to columns, functions, or Groupers
Groupers enable local references to axis,level,sort, while
the passed in axis, level, and sort are 'global'.
This routine tries to figure out what the passing in references
are and then creates a Grouping for each one, combined into
a BaseGrouper.
If observed & we have a categorical grouper, only show the observed
values.
If validate, then check for key/level overlaps.
"""
group_axis = obj._get_axis(axis)
# validate that the passed single level is compatible with the passed
# axis of the object
if level is not None:
# TODO: These if-block and else-block are almost same.
# MultiIndex instance check is removable, but it seems that there are
# some processes only for non-MultiIndex in else-block,
# eg. `obj.index.name != level`. We have to consider carefully whether
# these are applicable for MultiIndex. Even if these are applicable,
# we need to check if it makes no side effect to subsequent processes
# on the outside of this condition.
# (GH 17621)
if isinstance(group_axis, MultiIndex):
if is_list_like(level) and len(level) == 1:
level = level[0]
if key is None and is_scalar(level):
# Get the level values from group_axis
key = group_axis.get_level_values(level)
level = None
else:
# allow level to be a length-one list-like object
# (e.g., level=[0])
# GH 13901
if is_list_like(level):
nlevels = len(level)
if nlevels == 1:
level = level[0]
elif nlevels == 0:
raise ValueError("No group keys passed!")
else:
raise ValueError("multiple levels only valid with MultiIndex")
if isinstance(level, str):
if obj._get_axis(axis).name != level:
raise ValueError(
f"level name {level} is not the name "
f"of the {obj._get_axis_name(axis)}"
)
elif level > 0 or level < -1:
raise ValueError("level > 0 or level < -1 only valid with MultiIndex")
# NOTE: `group_axis` and `group_axis.get_level_values(level)`
# are same in this section.
level = None
key = group_axis
# a passed-in Grouper, directly convert
if isinstance(key, Grouper):
binner, grouper, obj = key._get_grouper(obj, validate=False)
if key.key is None:
return grouper, [], obj
else:
return grouper, [key.key], obj
# already have a BaseGrouper, just return it
elif isinstance(key, ops.BaseGrouper):
return key, [], obj
if not isinstance(key, list):
keys = [key]
match_axis_length = False
else:
keys = key
match_axis_length = len(keys) == len(group_axis)
# what are we after, exactly?
any_callable = any(callable(g) or isinstance(g, dict) for g in keys)
any_groupers = any(isinstance(g, Grouper) for g in keys)
any_arraylike = any(
isinstance(g, (list, tuple, Series, Index, np.ndarray)) for g in keys
)
# is this an index replacement?
if (
not any_callable
and not any_arraylike
and not any_groupers
and match_axis_length
and level is None
):
if isinstance(obj, DataFrame):
all_in_columns_index = all(
g in obj.columns or g in obj.index.names for g in keys
)
else:
assert isinstance(obj, Series)
all_in_columns_index = all(g in obj.index.names for g in keys)
if not all_in_columns_index:
keys = [com.asarray_tuplesafe(keys)]
if isinstance(level, (tuple, list)):
if key is None:
keys = [None] * len(level)
levels = level
else:
levels = [level] * len(keys)
groupings: List[Grouping] = []
exclusions: List[Hashable] = []
# if the actual grouper should be obj[key]
def is_in_axis(key) -> bool:
if not _is_label_like(key):
items = obj._data.items
try:
items.get_loc(key)
except (KeyError, TypeError):
# TypeError shows up here if we pass e.g. Int64Index
return False
return True
# if the grouper is obj[name]
def is_in_obj(gpr) -> bool:
if not hasattr(gpr, "name"):
return False
try:
return gpr is obj[gpr.name]
except (KeyError, IndexError):
return False
for i, (gpr, level) in enumerate(zip(keys, levels)):
if is_in_obj(gpr): # df.groupby(df['name'])
in_axis, name = True, gpr.name
exclusions.append(name)
elif is_in_axis(gpr): # df.groupby('name')
if gpr in obj:
if validate:
obj._check_label_or_level_ambiguity(gpr, axis=axis)
in_axis, name, gpr = True, gpr, obj[gpr]
exclusions.append(name)
elif obj._is_level_reference(gpr, axis=axis):
in_axis, name, level, gpr = False, None, gpr, None
else:
raise KeyError(gpr)
elif isinstance(gpr, Grouper) and gpr.key is not None:
# Add key to exclusions
exclusions.append(gpr.key)
in_axis, name = False, None
else:
in_axis, name = False, None
if is_categorical_dtype(gpr) and len(gpr) != obj.shape[axis]:
raise ValueError(
f"Length of grouper ({len(gpr)}) and axis ({obj.shape[axis]}) "
"must be same length"
)
# create the Grouping
# allow us to passing the actual Grouping as the gpr
ping = (
Grouping(
group_axis,
gpr,
obj=obj,
name=name,
level=level,
sort=sort,
observed=observed,
in_axis=in_axis,
)
if not isinstance(gpr, Grouping)
else gpr
)
groupings.append(ping)
if len(groupings) == 0 and len(obj):
raise ValueError("No group keys passed!")
elif len(groupings) == 0:
groupings.append(Grouping(Index([], dtype="int"), np.array([], dtype=np.intp)))
# create the internals grouper
grouper = ops.BaseGrouper(group_axis, groupings, sort=sort, mutated=mutated)
return grouper, exclusions, obj
def _is_label_like(val) -> bool:
return isinstance(val, (str, tuple)) or (val is not None and is_scalar(val))
def _convert_grouper(axis: Index, grouper):
if isinstance(grouper, dict):
return grouper.get
elif isinstance(grouper, Series):
if grouper.index.equals(axis):
return grouper._values
else:
return grouper.reindex(axis)._values
elif isinstance(grouper, (list, Series, Index, np.ndarray)):
if len(grouper) != len(axis):
raise ValueError("Grouper and axis must be same length")
return grouper
else:
return grouper
"""
Provide user facing operators for doing the split part of the
split-apply-combine paradigm.
"""
from typing import Dict, Hashable, List, Optional, Tuple
import numpy as np
from pandas._typing import FrameOrSeries
from pandas.util._decorators import cache_readonly
from pandas.core.dtypes.common import (
ensure_categorical,
is_categorical_dtype,
is_datetime64_dtype,
is_list_like,
is_scalar,
is_timedelta64_dtype,
)
from pandas.core.dtypes.generic import ABCSeries
import pandas.core.algorithms as algorithms
from pandas.core.arrays import Categorical, ExtensionArray
import pandas.core.common as com
from pandas.core.frame import DataFrame
from pandas.core.groupby import ops
from pandas.core.groupby.categorical import recode_for_groupby, recode_from_groupby
from pandas.core.indexes.api import CategoricalIndex, Index, MultiIndex
from pandas.core.indexes.base import InvalidIndexError
from pandas.core.series import Series
from pandas.io.formats.printing import pprint_thing
class Grouper:
"""
A Grouper allows the user to specify a groupby instruction for an object.
This specification will select a column via the key parameter, or if the
level and/or axis parameters are given, a level of the index of the target
object.
If `axis` and/or `level` are passed as keywords to both `Grouper` and
`groupby`, the values passed to `Grouper` take precedence.
Parameters
----------
key : str, defaults to None
Groupby key, which selects the grouping column of the target.
level : name/number, defaults to None
The level for the target index.
freq : str / frequency object, defaults to None
This will groupby the specified frequency if the target selection
(via key or level) is a datetime-like object. For full specification
of available frequencies, please see `here
<https://pandas.pydata.org/pandas-docs/stable/user_guide/timeseries.html#offset-aliases>`_.
axis : str, int, defaults to 0
Number/name of the axis.
sort : bool, default to False
Whether to sort the resulting labels.
closed : {'left' or 'right'}
Closed end of interval. Only when `freq` parameter is passed.
label : {'left' or 'right'}
Interval boundary to use for labeling.
Only when `freq` parameter is passed.
convention : {'start', 'end', 'e', 's'}
If grouper is PeriodIndex and `freq` parameter is passed.
base : int, default 0
Only when `freq` parameter is passed.
loffset : str, DateOffset, timedelta object
Only when `freq` parameter is passed.
Returns
-------
A specification for a groupby instruction
Examples
--------
Syntactic sugar for ``df.groupby('A')``
>>> df.groupby(Grouper(key='A'))
Specify a resample operation on the column 'date'
>>> df.groupby(Grouper(key='date', freq='60s'))
Specify a resample operation on the level 'date' on the columns axis
with a frequency of 60s
>>> df.groupby(Grouper(level='date', freq='60s', axis=1))
"""
_attributes: Tuple[str, ...] = ("key", "level", "freq", "axis", "sort")
def __new__(cls, *args, **kwargs):
if kwargs.get("freq") is not None:
from pandas.core.resample import TimeGrouper
cls = TimeGrouper
return super().__new__(cls)
def __init__(self, key=None, level=None, freq=None, axis=0, sort=False):
self.key = key
self.level = level
self.freq = freq
self.axis = axis
self.sort = sort
self.grouper = None
self.obj = None
self.indexer = None
self.binner = None
self._grouper = None
@property
def ax(self):
return self.grouper
def _get_grouper(self, obj, validate: bool = True):
"""
Parameters
----------
obj : the subject object
validate : boolean, default True
if True, validate the grouper
Returns
-------
a tuple of binner, grouper, obj (possibly sorted)
"""
self._set_grouper(obj)
self.grouper, _, self.obj = get_grouper(
self.obj,
[self.key],
axis=self.axis,
level=self.level,
sort=self.sort,
validate=validate,
)
return self.binner, self.grouper, self.obj
def _set_grouper(self, obj: FrameOrSeries, sort: bool = False):
"""
given an object and the specifications, setup the internal grouper
for this particular specification
Parameters
----------
obj : Series or DataFrame
sort : bool, default False
whether the resulting grouper should be sorted
"""
assert obj is not None
if self.key is not None and self.level is not None:
raise ValueError("The Grouper cannot specify both a key and a level!")
# Keep self.grouper value before overriding
if self._grouper is None:
self._grouper = self.grouper
# the key must be a valid info item
if self.key is not None:
key = self.key
# The 'on' is already defined
if getattr(self.grouper, "name", None) == key and isinstance(
obj, ABCSeries
):
ax = self._grouper.take(obj.index)
else:
if key not in obj._info_axis:
raise KeyError(f"The grouper name {key} is not found")
ax = Index(obj[key], name=key)
else:
ax = obj._get_axis(self.axis)
if self.level is not None:
level = self.level
# if a level is given it must be a mi level or
# equivalent to the axis name
if isinstance(ax, MultiIndex):
level = ax._get_level_number(level)
ax = Index(ax._get_level_values(level), name=ax.names[level])
else:
if level not in (0, ax.name):
raise ValueError(f"The level {level} is not valid")
# possibly sort
if (self.sort or sort) and not ax.is_monotonic:
# use stable sort to support first, last, nth
indexer = self.indexer = ax.argsort(kind="mergesort")
ax = ax.take(indexer)
obj = obj.take(indexer, axis=self.axis)
self.obj = obj
self.grouper = ax
return self.grouper
@property
def groups(self):
return self.grouper.groups
def __repr__(self) -> str:
attrs_list = (
f"{attr_name}={repr(getattr(self, attr_name))}"
for attr_name in self._attributes
if getattr(self, attr_name) is not None
)
attrs = ", ".join(attrs_list)
cls_name = type(self).__name__
return f"{cls_name}({attrs})"
class Grouping:
"""
Holds the grouping information for a single key
Parameters
----------
index : Index
grouper :
obj Union[DataFrame, Series]:
name :
level :
observed : bool, default False
If we are a Categorical, use the observed values
in_axis : if the Grouping is a column in self.obj and hence among
Groupby.exclusions list
Returns
-------
**Attributes**:
* indices : dict of {group -> index_list}
* codes : ndarray, group codes
* group_index : unique groups
* groups : dict of {group -> label_list}
"""
def __init__(
self,
index: Index,
grouper=None,
obj: Optional[FrameOrSeries] = None,
name=None,
level=None,
sort: bool = True,
observed: bool = False,
in_axis: bool = False,
):
self.name = name
self.level = level
self.grouper = _convert_grouper(index, grouper)
self.all_grouper = None
self.index = index
self.sort = sort
self.obj = obj
self.observed = observed
self.in_axis = in_axis
# right place for this?
if isinstance(grouper, (Series, Index)) and name is None:
self.name = grouper.name
if isinstance(grouper, MultiIndex):
self.grouper = grouper.values
# we have a single grouper which may be a myriad of things,
# some of which are dependent on the passing in level
if level is not None:
if not isinstance(level, int):
if level not in index.names:
raise AssertionError(f"Level {level} not in index")
level = index.names.index(level)
if self.name is None:
self.name = index.names[level]
(
self.grouper,
self._codes,
self._group_index,
) = index._get_grouper_for_level(self.grouper, level)
# a passed Grouper like, directly get the grouper in the same way
# as single grouper groupby, use the group_info to get codes
elif isinstance(self.grouper, Grouper):
# get the new grouper; we already have disambiguated
# what key/level refer to exactly, don't need to
# check again as we have by this point converted these
# to an actual value (rather than a pd.Grouper)
_, grouper, _ = self.grouper._get_grouper(self.obj, validate=False)
if self.name is None:
self.name = grouper.result_index.name
self.obj = self.grouper.obj
self.grouper = grouper._get_grouper()
else:
if self.grouper is None and self.name is not None and self.obj is not None:
self.grouper = self.obj[self.name]
elif isinstance(self.grouper, (list, tuple)):
self.grouper = com.asarray_tuplesafe(self.grouper)
# a passed Categorical
elif is_categorical_dtype(self.grouper):
self.grouper, self.all_grouper = recode_for_groupby(
self.grouper, self.sort, observed
)
categories = self.grouper.categories
# we make a CategoricalIndex out of the cat grouper
# preserving the categories / ordered attributes
self._codes = self.grouper.codes
if observed:
codes = algorithms.unique1d(self.grouper.codes)
codes = codes[codes != -1]
if sort or self.grouper.ordered:
codes = np.sort(codes)
else:
codes = np.arange(len(categories))
self._group_index = CategoricalIndex(
Categorical.from_codes(
codes=codes, categories=categories, ordered=self.grouper.ordered
),
name=self.name,
)
# we are done
if isinstance(self.grouper, Grouping):
self.grouper = self.grouper.grouper
# no level passed
elif not isinstance(
self.grouper, (Series, Index, ExtensionArray, np.ndarray)
):
if getattr(self.grouper, "ndim", 1) != 1:
t = self.name or str(type(self.grouper))
raise ValueError(f"Grouper for '{t}' not 1-dimensional")
self.grouper = self.index.map(self.grouper)
if not (
hasattr(self.grouper, "__len__")
and len(self.grouper) == len(self.index)
):
grper = pprint_thing(self.grouper)
errmsg = (
"Grouper result violates len(labels) == "
f"len(data)\nresult: {grper}"
)
self.grouper = None # Try for sanity
raise AssertionError(errmsg)
# if we have a date/time-like grouper, make sure that we have
# Timestamps like
if getattr(self.grouper, "dtype", None) is not None:
if is_datetime64_dtype(self.grouper):
self.grouper = self.grouper.astype("datetime64[ns]")
elif is_timedelta64_dtype(self.grouper):
self.grouper = self.grouper.astype("timedelta64[ns]")
def __repr__(self) -> str:
return f"Grouping({self.name})"
def __iter__(self):
return iter(self.indices)
_codes: Optional[np.ndarray] = None
_group_index: Optional[Index] = None
@property
def ngroups(self) -> int:
return len(self.group_index)
@cache_readonly
def indices(self):
# we have a list of groupers
if isinstance(self.grouper, ops.BaseGrouper):
return self.grouper.indices
values = ensure_categorical(self.grouper)
return values._reverse_indexer()
@property
def codes(self) -> np.ndarray:
if self._codes is None:
self._make_codes()
return self._codes
@cache_readonly
def result_index(self) -> Index:
if self.all_grouper is not None:
return recode_from_groupby(self.all_grouper, self.sort, self.group_index)
return self.group_index
@property
def group_index(self) -> Index:
if self._group_index is None:
self._make_codes()
assert self._group_index is not None
return self._group_index
def _make_codes(self) -> None:
if self._codes is None or self._group_index is None:
# we have a list of groupers
if isinstance(self.grouper, ops.BaseGrouper):
codes = self.grouper.codes_info
uniques = self.grouper.result_index
else:
codes, uniques = algorithms.factorize(self.grouper, sort=self.sort)
uniques = Index(uniques, name=self.name)
self._codes = codes
self._group_index = uniques
@cache_readonly
def groups(self) -> Dict[Hashable, np.ndarray]:
return self.index.groupby(Categorical.from_codes(self.codes, self.group_index))
def get_grouper(
obj: FrameOrSeries,
key=None,
axis: int = 0,
level=None,
sort: bool = True,
observed: bool = False,
mutated: bool = False,
validate: bool = True,
) -> "Tuple[ops.BaseGrouper, List[Hashable], FrameOrSeries]":
"""
Create and return a BaseGrouper, which is an internal
mapping of how to create the grouper indexers.
This may be composed of multiple Grouping objects, indicating
multiple groupers
Groupers are ultimately index mappings. They can originate as:
index mappings, keys to columns, functions, or Groupers
Groupers enable local references to axis,level,sort, while
the passed in axis, level, and sort are 'global'.
This routine tries to figure out what the passing in references
are and then creates a Grouping for each one, combined into
a BaseGrouper.
If observed & we have a categorical grouper, only show the observed
values.
If validate, then check for key/level overlaps.
"""
group_axis = obj._get_axis(axis)
# validate that the passed single level is compatible with the passed
# axis of the object
if level is not None:
# TODO: These if-block and else-block are almost same.
# MultiIndex instance check is removable, but it seems that there are
# some processes only for non-MultiIndex in else-block,
# eg. `obj.index.name != level`. We have to consider carefully whether
# these are applicable for MultiIndex. Even if these are applicable,
# we need to check if it makes no side effect to subsequent processes
# on the outside of this condition.
# (GH 17621)
if isinstance(group_axis, MultiIndex):
if is_list_like(level) and len(level) == 1:
level = level[0]
if key is None and is_scalar(level):
# Get the level values from group_axis
key = group_axis.get_level_values(level)
level = None
else:
# allow level to be a length-one list-like object
# (e.g., level=[0])
# GH 13901
if is_list_like(level):
nlevels = len(level)
if nlevels == 1:
level = level[0]
elif nlevels == 0:
raise ValueError("No group keys passed!")
else:
raise ValueError("multiple levels only valid with MultiIndex")
if isinstance(level, str):
if obj._get_axis(axis).name != level:
raise ValueError(
f"level name {level} is not the name "
f"of the {obj._get_axis_name(axis)}"
)
elif level > 0 or level < -1:
raise ValueError("level > 0 or level < -1 only valid with MultiIndex")
# NOTE: `group_axis` and `group_axis.get_level_values(level)`
# are same in this section.
level = None
key = group_axis
# a passed-in Grouper, directly convert
if isinstance(key, Grouper):
binner, grouper, obj = key._get_grouper(obj, validate=False)
if key.key is None:
return grouper, [], obj
else:
return grouper, [key.key], obj
# already have a BaseGrouper, just return it
elif isinstance(key, ops.BaseGrouper):
return key, [], obj
if not isinstance(key, list):
keys = [key]
match_axis_length = False
else:
keys = key
match_axis_length = len(keys) == len(group_axis)
# what are we after, exactly?
any_callable = any(callable(g) or isinstance(g, dict) for g in keys)
any_groupers = any(isinstance(g, Grouper) for g in keys)
any_arraylike = any(
isinstance(g, (list, tuple, Series, Index, np.ndarray)) for g in keys
)
# is this an index replacement?
if (
not any_callable
and not any_arraylike
and not any_groupers
and match_axis_length
and level is None
):
if isinstance(obj, DataFrame):
all_in_columns_index = all(
g in obj.columns or g in obj.index.names for g in keys
)
else:
assert isinstance(obj, Series)
all_in_columns_index = all(g in obj.index.names for g in keys)
if not all_in_columns_index:
keys = [com.asarray_tuplesafe(keys)]
if isinstance(level, (tuple, list)):
if key is None:
keys = [None] * len(level)
levels = level
else:
levels = [level] * len(keys)
groupings: List[Grouping] = []
exclusions: List[Hashable] = []
# if the actual grouper should be obj[key]
def is_in_axis(key) -> bool:
if not _is_label_like(key):
items = obj._data.items
try:
items.get_loc(key)
except (KeyError, TypeError, InvalidIndexError):
# TypeError shows up here if we pass e.g. Int64Index
return False
return True
# if the grouper is obj[name]
def is_in_obj(gpr) -> bool:
if not hasattr(gpr, "name"):
return False
try:
return gpr is obj[gpr.name]
except (KeyError, IndexError):
return False
for i, (gpr, level) in enumerate(zip(keys, levels)):
if is_in_obj(gpr): # df.groupby(df['name'])
in_axis, name = True, gpr.name
exclusions.append(name)
elif is_in_axis(gpr): # df.groupby('name')
if gpr in obj:
if validate:
obj._check_label_or_level_ambiguity(gpr, axis=axis)
in_axis, name, gpr = True, gpr, obj[gpr]
exclusions.append(name)
elif obj._is_level_reference(gpr, axis=axis):
in_axis, name, level, gpr = False, None, gpr, None
else:
raise KeyError(gpr)
elif isinstance(gpr, Grouper) and gpr.key is not None:
# Add key to exclusions
exclusions.append(gpr.key)
in_axis, name = False, None
else:
in_axis, name = False, None
if is_categorical_dtype(gpr) and len(gpr) != obj.shape[axis]:
raise ValueError(
f"Length of grouper ({len(gpr)}) and axis ({obj.shape[axis]}) "
"must be same length"
)
# create the Grouping
# allow us to passing the actual Grouping as the gpr
ping = (
Grouping(
group_axis,
gpr,
obj=obj,
name=name,
level=level,
sort=sort,
observed=observed,
in_axis=in_axis,
)
if not isinstance(gpr, Grouping)
else gpr
)
groupings.append(ping)
if len(groupings) == 0 and len(obj):
raise ValueError("No group keys passed!")
elif len(groupings) == 0:
groupings.append(Grouping(Index([], dtype="int"), np.array([], dtype=np.intp)))
# create the internals grouper
grouper = ops.BaseGrouper(group_axis, groupings, sort=sort, mutated=mutated)
return grouper, exclusions, obj
def _is_label_like(val) -> bool:
return isinstance(val, (str, tuple)) or (val is not None and is_scalar(val))
def _convert_grouper(axis: Index, grouper):
if isinstance(grouper, dict):
return grouper.get
elif isinstance(grouper, Series):
if grouper.index.equals(axis):
return grouper._values
else:
return grouper.reindex(axis)._values
elif isinstance(grouper, (list, Series, Index, np.ndarray)):
if len(grouper) != len(axis):
raise ValueError("Grouper and axis must be same length")
return grouper
else:
return grouper
| BugsInPy/BugsInPy/temp/projects/pandas/bug-79-fixed/pandas/pandas/core/groupby/grouper.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-79-buggy/pandas/pandas/core/groupby/grouper.py |
pandas-bug-39 | """
Functions to generate methods and pin them to the appropriate classes.
"""
import operator
from pandas.core.dtypes.generic import ABCDataFrame, ABCSeries, ABCSparseArray
from pandas.core.ops.roperator import (
radd,
rand_,
rdivmod,
rfloordiv,
rmod,
rmul,
ror_,
rpow,
rsub,
rtruediv,
rxor,
)
def _get_method_wrappers(cls):
"""
Find the appropriate operation-wrappers to use when defining flex/special
arithmetic, boolean, and comparison operations with the given class.
Parameters
----------
cls : class
Returns
-------
arith_flex : function or None
comp_flex : function or None
arith_special : function
comp_special : function
bool_special : function
Notes
-----
None is only returned for SparseArray
"""
# TODO: make these non-runtime imports once the relevant functions
# are no longer in __init__
from pandas.core.ops import (
_arith_method_FRAME,
_arith_method_SERIES,
_bool_method_SERIES,
_comp_method_FRAME,
_comp_method_SERIES,
_flex_comp_method_FRAME,
_flex_method_SERIES,
)
if issubclass(cls, ABCSeries):
# Just Series
arith_flex = _flex_method_SERIES
comp_flex = _flex_method_SERIES
arith_special = _arith_method_SERIES
comp_special = _comp_method_SERIES
bool_special = _bool_method_SERIES
elif issubclass(cls, ABCDataFrame):
arith_flex = _arith_method_FRAME
comp_flex = _flex_comp_method_FRAME
arith_special = _arith_method_FRAME
comp_special = _comp_method_FRAME
bool_special = _arith_method_FRAME
return arith_flex, comp_flex, arith_special, comp_special, bool_special
def add_special_arithmetic_methods(cls):
"""
Adds the full suite of special arithmetic methods (``__add__``,
``__sub__``, etc.) to the class.
Parameters
----------
cls : class
special methods will be defined and pinned to this class
"""
_, _, arith_method, comp_method, bool_method = _get_method_wrappers(cls)
new_methods = _create_methods(
cls, arith_method, comp_method, bool_method, special=True
)
# inplace operators (I feel like these should get passed an `inplace=True`
# or just be removed
def _wrap_inplace_method(method):
"""
return an inplace wrapper for this method
"""
def f(self, other):
result = method(self, other)
# this makes sure that we are aligned like the input
# we are updating inplace so we want to ignore is_copy
self._update_inplace(
result.reindex_like(self, copy=False)._data, verify_is_copy=False
)
return self
name = method.__name__.strip("__")
f.__name__ = f"__i{name}__"
return f
new_methods.update(
dict(
__iadd__=_wrap_inplace_method(new_methods["__add__"]),
__isub__=_wrap_inplace_method(new_methods["__sub__"]),
__imul__=_wrap_inplace_method(new_methods["__mul__"]),
__itruediv__=_wrap_inplace_method(new_methods["__truediv__"]),
__ifloordiv__=_wrap_inplace_method(new_methods["__floordiv__"]),
__imod__=_wrap_inplace_method(new_methods["__mod__"]),
__ipow__=_wrap_inplace_method(new_methods["__pow__"]),
)
)
new_methods.update(
dict(
__iand__=_wrap_inplace_method(new_methods["__and__"]),
__ior__=_wrap_inplace_method(new_methods["__or__"]),
__ixor__=_wrap_inplace_method(new_methods["__xor__"]),
)
)
_add_methods(cls, new_methods=new_methods)
def add_flex_arithmetic_methods(cls):
"""
Adds the full suite of flex arithmetic methods (``pow``, ``mul``, ``add``)
to the class.
Parameters
----------
cls : class
flex methods will be defined and pinned to this class
"""
flex_arith_method, flex_comp_method, _, _, _ = _get_method_wrappers(cls)
new_methods = _create_methods(
cls, flex_arith_method, flex_comp_method, bool_method=None, special=False
)
new_methods.update(
dict(
multiply=new_methods["mul"],
subtract=new_methods["sub"],
divide=new_methods["div"],
)
)
# opt out of bool flex methods for now
assert not any(kname in new_methods for kname in ("ror_", "rxor", "rand_"))
_add_methods(cls, new_methods=new_methods)
def _create_methods(cls, arith_method, comp_method, bool_method, special):
# creates actual methods based upon arithmetic, comp and bool method
# constructors.
have_divmod = issubclass(cls, ABCSeries)
# divmod is available for Series
new_methods = dict(
add=arith_method(cls, operator.add, special),
radd=arith_method(cls, radd, special),
sub=arith_method(cls, operator.sub, special),
mul=arith_method(cls, operator.mul, special),
truediv=arith_method(cls, operator.truediv, special),
floordiv=arith_method(cls, operator.floordiv, special),
# Causes a floating point exception in the tests when numexpr enabled,
# so for now no speedup
mod=arith_method(cls, operator.mod, special),
pow=arith_method(cls, operator.pow, special),
# not entirely sure why this is necessary, but previously was included
# so it's here to maintain compatibility
rmul=arith_method(cls, rmul, special),
rsub=arith_method(cls, rsub, special),
rtruediv=arith_method(cls, rtruediv, special),
rfloordiv=arith_method(cls, rfloordiv, special),
rpow=arith_method(cls, rpow, special),
rmod=arith_method(cls, rmod, special),
)
new_methods["div"] = new_methods["truediv"]
new_methods["rdiv"] = new_methods["rtruediv"]
if have_divmod:
# divmod doesn't have an op that is supported by numexpr
new_methods["divmod"] = arith_method(cls, divmod, special)
new_methods["rdivmod"] = arith_method(cls, rdivmod, special)
new_methods.update(
dict(
eq=comp_method(cls, operator.eq, special),
ne=comp_method(cls, operator.ne, special),
lt=comp_method(cls, operator.lt, special),
gt=comp_method(cls, operator.gt, special),
le=comp_method(cls, operator.le, special),
ge=comp_method(cls, operator.ge, special),
)
)
if bool_method:
new_methods.update(
dict(
and_=bool_method(cls, operator.and_, special),
or_=bool_method(cls, operator.or_, special),
# For some reason ``^`` wasn't used in original.
xor=bool_method(cls, operator.xor, special),
rand_=bool_method(cls, rand_, special),
ror_=bool_method(cls, ror_, special),
rxor=bool_method(cls, rxor, special),
)
)
if special:
dunderize = lambda x: f"__{x.strip('_')}__"
else:
dunderize = lambda x: x
new_methods = {dunderize(k): v for k, v in new_methods.items()}
return new_methods
def _add_methods(cls, new_methods):
for name, method in new_methods.items():
# For most methods, if we find that the class already has a method
# of the same name, it is OK to over-write it. The exception is
# inplace methods (__iadd__, __isub__, ...) for SparseArray, which
# retain the np.ndarray versions.
force = not (issubclass(cls, ABCSparseArray) and name.startswith("__i"))
if force or name not in cls.__dict__:
setattr(cls, name, method)
"""
Functions to generate methods and pin them to the appropriate classes.
"""
import operator
from pandas.core.dtypes.generic import ABCDataFrame, ABCSeries, ABCSparseArray
from pandas.core.ops.roperator import (
radd,
rand_,
rdivmod,
rfloordiv,
rmod,
rmul,
ror_,
rpow,
rsub,
rtruediv,
rxor,
)
def _get_method_wrappers(cls):
"""
Find the appropriate operation-wrappers to use when defining flex/special
arithmetic, boolean, and comparison operations with the given class.
Parameters
----------
cls : class
Returns
-------
arith_flex : function or None
comp_flex : function or None
arith_special : function
comp_special : function
bool_special : function
Notes
-----
None is only returned for SparseArray
"""
# TODO: make these non-runtime imports once the relevant functions
# are no longer in __init__
from pandas.core.ops import (
_arith_method_FRAME,
_arith_method_SERIES,
_bool_method_SERIES,
_comp_method_FRAME,
_comp_method_SERIES,
_flex_comp_method_FRAME,
_flex_method_SERIES,
)
if issubclass(cls, ABCSeries):
# Just Series
arith_flex = _flex_method_SERIES
comp_flex = _flex_method_SERIES
arith_special = _arith_method_SERIES
comp_special = _comp_method_SERIES
bool_special = _bool_method_SERIES
elif issubclass(cls, ABCDataFrame):
arith_flex = _arith_method_FRAME
comp_flex = _flex_comp_method_FRAME
arith_special = _arith_method_FRAME
comp_special = _comp_method_FRAME
bool_special = _arith_method_FRAME
return arith_flex, comp_flex, arith_special, comp_special, bool_special
def add_special_arithmetic_methods(cls):
"""
Adds the full suite of special arithmetic methods (``__add__``,
``__sub__``, etc.) to the class.
Parameters
----------
cls : class
special methods will be defined and pinned to this class
"""
_, _, arith_method, comp_method, bool_method = _get_method_wrappers(cls)
new_methods = _create_methods(
cls, arith_method, comp_method, bool_method, special=True
)
# inplace operators (I feel like these should get passed an `inplace=True`
# or just be removed
def _wrap_inplace_method(method):
"""
return an inplace wrapper for this method
"""
def f(self, other):
result = method(self, other)
# Delete cacher
self._reset_cacher()
# this makes sure that we are aligned like the input
# we are updating inplace so we want to ignore is_copy
self._update_inplace(
result.reindex_like(self, copy=False)._data, verify_is_copy=False
)
return self
name = method.__name__.strip("__")
f.__name__ = f"__i{name}__"
return f
new_methods.update(
dict(
__iadd__=_wrap_inplace_method(new_methods["__add__"]),
__isub__=_wrap_inplace_method(new_methods["__sub__"]),
__imul__=_wrap_inplace_method(new_methods["__mul__"]),
__itruediv__=_wrap_inplace_method(new_methods["__truediv__"]),
__ifloordiv__=_wrap_inplace_method(new_methods["__floordiv__"]),
__imod__=_wrap_inplace_method(new_methods["__mod__"]),
__ipow__=_wrap_inplace_method(new_methods["__pow__"]),
)
)
new_methods.update(
dict(
__iand__=_wrap_inplace_method(new_methods["__and__"]),
__ior__=_wrap_inplace_method(new_methods["__or__"]),
__ixor__=_wrap_inplace_method(new_methods["__xor__"]),
)
)
_add_methods(cls, new_methods=new_methods)
def add_flex_arithmetic_methods(cls):
"""
Adds the full suite of flex arithmetic methods (``pow``, ``mul``, ``add``)
to the class.
Parameters
----------
cls : class
flex methods will be defined and pinned to this class
"""
flex_arith_method, flex_comp_method, _, _, _ = _get_method_wrappers(cls)
new_methods = _create_methods(
cls, flex_arith_method, flex_comp_method, bool_method=None, special=False
)
new_methods.update(
dict(
multiply=new_methods["mul"],
subtract=new_methods["sub"],
divide=new_methods["div"],
)
)
# opt out of bool flex methods for now
assert not any(kname in new_methods for kname in ("ror_", "rxor", "rand_"))
_add_methods(cls, new_methods=new_methods)
def _create_methods(cls, arith_method, comp_method, bool_method, special):
# creates actual methods based upon arithmetic, comp and bool method
# constructors.
have_divmod = issubclass(cls, ABCSeries)
# divmod is available for Series
new_methods = dict(
add=arith_method(cls, operator.add, special),
radd=arith_method(cls, radd, special),
sub=arith_method(cls, operator.sub, special),
mul=arith_method(cls, operator.mul, special),
truediv=arith_method(cls, operator.truediv, special),
floordiv=arith_method(cls, operator.floordiv, special),
# Causes a floating point exception in the tests when numexpr enabled,
# so for now no speedup
mod=arith_method(cls, operator.mod, special),
pow=arith_method(cls, operator.pow, special),
# not entirely sure why this is necessary, but previously was included
# so it's here to maintain compatibility
rmul=arith_method(cls, rmul, special),
rsub=arith_method(cls, rsub, special),
rtruediv=arith_method(cls, rtruediv, special),
rfloordiv=arith_method(cls, rfloordiv, special),
rpow=arith_method(cls, rpow, special),
rmod=arith_method(cls, rmod, special),
)
new_methods["div"] = new_methods["truediv"]
new_methods["rdiv"] = new_methods["rtruediv"]
if have_divmod:
# divmod doesn't have an op that is supported by numexpr
new_methods["divmod"] = arith_method(cls, divmod, special)
new_methods["rdivmod"] = arith_method(cls, rdivmod, special)
new_methods.update(
dict(
eq=comp_method(cls, operator.eq, special),
ne=comp_method(cls, operator.ne, special),
lt=comp_method(cls, operator.lt, special),
gt=comp_method(cls, operator.gt, special),
le=comp_method(cls, operator.le, special),
ge=comp_method(cls, operator.ge, special),
)
)
if bool_method:
new_methods.update(
dict(
and_=bool_method(cls, operator.and_, special),
or_=bool_method(cls, operator.or_, special),
# For some reason ``^`` wasn't used in original.
xor=bool_method(cls, operator.xor, special),
rand_=bool_method(cls, rand_, special),
ror_=bool_method(cls, ror_, special),
rxor=bool_method(cls, rxor, special),
)
)
if special:
dunderize = lambda x: f"__{x.strip('_')}__"
else:
dunderize = lambda x: x
new_methods = {dunderize(k): v for k, v in new_methods.items()}
return new_methods
def _add_methods(cls, new_methods):
for name, method in new_methods.items():
# For most methods, if we find that the class already has a method
# of the same name, it is OK to over-write it. The exception is
# inplace methods (__iadd__, __isub__, ...) for SparseArray, which
# retain the np.ndarray versions.
force = not (issubclass(cls, ABCSparseArray) and name.startswith("__i"))
if force or name not in cls.__dict__:
setattr(cls, name, method)
| BugsInPy/BugsInPy/temp/projects/pandas/bug-39-fixed/pandas/pandas/core/ops/methods.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-39-buggy/pandas/pandas/core/ops/methods.py |
pandas-bug-47 | """
DataFrame
---------
An efficient 2D container for potentially mixed-type time series or other
labeled data series.
Similar to its R counterpart, data.frame, except providing automatic data
alignment and a host of useful data manipulation methods having to do with the
labeling information
"""
import collections
from collections import abc
import datetime
from io import StringIO
import itertools
from textwrap import dedent
from typing import (
IO,
TYPE_CHECKING,
Any,
Dict,
FrozenSet,
Hashable,
Iterable,
List,
Optional,
Sequence,
Set,
Tuple,
Type,
Union,
cast,
)
import warnings
import numpy as np
import numpy.ma as ma
from pandas._config import get_option
from pandas._libs import algos as libalgos, lib, properties
from pandas._typing import Axes, Axis, Dtype, FilePathOrBuffer, Label, Level, Renamer
from pandas.compat import PY37
from pandas.compat._optional import import_optional_dependency
from pandas.compat.numpy import function as nv
from pandas.util._decorators import (
Appender,
Substitution,
deprecate_kwarg,
doc,
rewrite_axis_style_signature,
)
from pandas.util._validators import (
validate_axis_style_args,
validate_bool_kwarg,
validate_percentile,
)
from pandas.core.dtypes.cast import (
cast_scalar_to_array,
coerce_to_dtypes,
find_common_type,
infer_dtype_from_scalar,
invalidate_string_dtypes,
maybe_cast_to_datetime,
maybe_convert_platform,
maybe_downcast_to_dtype,
maybe_infer_to_datetimelike,
maybe_upcast,
maybe_upcast_putmask,
validate_numeric_casting,
)
from pandas.core.dtypes.common import (
ensure_float64,
ensure_int64,
ensure_platform_int,
infer_dtype_from_object,
is_bool_dtype,
is_datetime64_any_dtype,
is_dict_like,
is_dtype_equal,
is_extension_array_dtype,
is_float_dtype,
is_hashable,
is_integer,
is_integer_dtype,
is_iterator,
is_list_like,
is_named_tuple,
is_object_dtype,
is_period_dtype,
is_scalar,
is_sequence,
needs_i8_conversion,
)
from pandas.core.dtypes.generic import (
ABCDataFrame,
ABCIndexClass,
ABCMultiIndex,
ABCSeries,
)
from pandas.core.dtypes.missing import isna, notna
from pandas.core import algorithms, common as com, nanops, ops
from pandas.core.accessor import CachedAccessor
from pandas.core.arrays import Categorical, ExtensionArray
from pandas.core.arrays.datetimelike import DatetimeLikeArrayMixin as DatetimeLikeArray
from pandas.core.arrays.sparse import SparseFrameAccessor
from pandas.core.generic import NDFrame, _shared_docs
from pandas.core.indexes import base as ibase
from pandas.core.indexes.api import Index, ensure_index, ensure_index_from_sequences
from pandas.core.indexes.datetimes import DatetimeIndex
from pandas.core.indexes.multi import MultiIndex, maybe_droplevels
from pandas.core.indexes.period import PeriodIndex
from pandas.core.indexing import check_bool_indexer, convert_to_index_sliceable
from pandas.core.internals import BlockManager
from pandas.core.internals.construction import (
arrays_to_mgr,
get_names_from_index,
init_dict,
init_ndarray,
masked_rec_array_to_mgr,
reorder_arrays,
sanitize_index,
to_arrays,
)
from pandas.core.ops.missing import dispatch_fill_zeros
from pandas.core.series import Series
from pandas.io.common import get_filepath_or_buffer
from pandas.io.formats import console, format as fmt
from pandas.io.formats.info import info
import pandas.plotting
if TYPE_CHECKING:
from pandas.core.groupby.generic import DataFrameGroupBy
from pandas.io.formats.style import Styler
# ---------------------------------------------------------------------
# Docstring templates
_shared_doc_kwargs = dict(
axes="index, columns",
klass="DataFrame",
axes_single_arg="{0 or 'index', 1 or 'columns'}",
axis="""axis : {0 or 'index', 1 or 'columns'}, default 0
If 0 or 'index': apply function to each column.
If 1 or 'columns': apply function to each row.""",
optional_by="""
by : str or list of str
Name or list of names to sort by.
- if `axis` is 0 or `'index'` then `by` may contain index
levels and/or column labels.
- if `axis` is 1 or `'columns'` then `by` may contain column
levels and/or index labels.
.. versionchanged:: 0.23.0
Allow specifying index or column level names.""",
versionadded_to_excel="",
optional_labels="""labels : array-like, optional
New labels / index to conform the axis specified by 'axis' to.""",
optional_axis="""axis : int or str, optional
Axis to target. Can be either the axis name ('index', 'columns')
or number (0, 1).""",
)
_numeric_only_doc = """numeric_only : boolean, default None
Include only float, int, boolean data. If None, will attempt to use
everything, then use only numeric data
"""
_merge_doc = """
Merge DataFrame or named Series objects with a database-style join.
The join is done on columns or indexes. If joining columns on
columns, the DataFrame indexes *will be ignored*. Otherwise if joining indexes
on indexes or indexes on a column or columns, the index will be passed on.
Parameters
----------%s
right : DataFrame or named Series
Object to merge with.
how : {'left', 'right', 'outer', 'inner'}, default 'inner'
Type of merge to be performed.
* left: use only keys from left frame, similar to a SQL left outer join;
preserve key order.
* right: use only keys from right frame, similar to a SQL right outer join;
preserve key order.
* outer: use union of keys from both frames, similar to a SQL full outer
join; sort keys lexicographically.
* inner: use intersection of keys from both frames, similar to a SQL inner
join; preserve the order of the left keys.
on : label or list
Column or index level names to join on. These must be found in both
DataFrames. If `on` is None and not merging on indexes then this defaults
to the intersection of the columns in both DataFrames.
left_on : label or list, or array-like
Column or index level names to join on in the left DataFrame. Can also
be an array or list of arrays of the length of the left DataFrame.
These arrays are treated as if they are columns.
right_on : label or list, or array-like
Column or index level names to join on in the right DataFrame. Can also
be an array or list of arrays of the length of the right DataFrame.
These arrays are treated as if they are columns.
left_index : bool, default False
Use the index from the left DataFrame as the join key(s). If it is a
MultiIndex, the number of keys in the other DataFrame (either the index
or a number of columns) must match the number of levels.
right_index : bool, default False
Use the index from the right DataFrame as the join key. Same caveats as
left_index.
sort : bool, default False
Sort the join keys lexicographically in the result DataFrame. If False,
the order of the join keys depends on the join type (how keyword).
suffixes : tuple of (str, str), default ('_x', '_y')
Suffix to apply to overlapping column names in the left and right
side, respectively. To raise an exception on overlapping columns use
(False, False).
copy : bool, default True
If False, avoid copy if possible.
indicator : bool or str, default False
If True, adds a column to output DataFrame called "_merge" with
information on the source of each row.
If string, column with information on source of each row will be added to
output DataFrame, and column will be named value of string.
Information column is Categorical-type and takes on a value of "left_only"
for observations whose merge key only appears in 'left' DataFrame,
"right_only" for observations whose merge key only appears in 'right'
DataFrame, and "both" if the observation's merge key is found in both.
validate : str, optional
If specified, checks if merge is of specified type.
* "one_to_one" or "1:1": check if merge keys are unique in both
left and right datasets.
* "one_to_many" or "1:m": check if merge keys are unique in left
dataset.
* "many_to_one" or "m:1": check if merge keys are unique in right
dataset.
* "many_to_many" or "m:m": allowed, but does not result in checks.
.. versionadded:: 0.21.0
Returns
-------
DataFrame
A DataFrame of the two merged objects.
See Also
--------
merge_ordered : Merge with optional filling/interpolation.
merge_asof : Merge on nearest keys.
DataFrame.join : Similar method using indices.
Notes
-----
Support for specifying index levels as the `on`, `left_on`, and
`right_on` parameters was added in version 0.23.0
Support for merging named Series objects was added in version 0.24.0
Examples
--------
>>> df1 = pd.DataFrame({'lkey': ['foo', 'bar', 'baz', 'foo'],
... 'value': [1, 2, 3, 5]})
>>> df2 = pd.DataFrame({'rkey': ['foo', 'bar', 'baz', 'foo'],
... 'value': [5, 6, 7, 8]})
>>> df1
lkey value
0 foo 1
1 bar 2
2 baz 3
3 foo 5
>>> df2
rkey value
0 foo 5
1 bar 6
2 baz 7
3 foo 8
Merge df1 and df2 on the lkey and rkey columns. The value columns have
the default suffixes, _x and _y, appended.
>>> df1.merge(df2, left_on='lkey', right_on='rkey')
lkey value_x rkey value_y
0 foo 1 foo 5
1 foo 1 foo 8
2 foo 5 foo 5
3 foo 5 foo 8
4 bar 2 bar 6
5 baz 3 baz 7
Merge DataFrames df1 and df2 with specified left and right suffixes
appended to any overlapping columns.
>>> df1.merge(df2, left_on='lkey', right_on='rkey',
... suffixes=('_left', '_right'))
lkey value_left rkey value_right
0 foo 1 foo 5
1 foo 1 foo 8
2 foo 5 foo 5
3 foo 5 foo 8
4 bar 2 bar 6
5 baz 3 baz 7
Merge DataFrames df1 and df2, but raise an exception if the DataFrames have
any overlapping columns.
>>> df1.merge(df2, left_on='lkey', right_on='rkey', suffixes=(False, False))
Traceback (most recent call last):
...
ValueError: columns overlap but no suffix specified:
Index(['value'], dtype='object')
"""
# -----------------------------------------------------------------------
# DataFrame class
class DataFrame(NDFrame):
"""
Two-dimensional, size-mutable, potentially heterogeneous tabular data.
Data structure also contains labeled axes (rows and columns).
Arithmetic operations align on both row and column labels. Can be
thought of as a dict-like container for Series objects. The primary
pandas data structure.
Parameters
----------
data : ndarray (structured or homogeneous), Iterable, dict, or DataFrame
Dict can contain Series, arrays, constants, or list-like objects.
.. versionchanged:: 0.23.0
If data is a dict, column order follows insertion-order for
Python 3.6 and later.
.. versionchanged:: 0.25.0
If data is a list of dicts, column order follows insertion-order
for Python 3.6 and later.
index : Index or array-like
Index to use for resulting frame. Will default to RangeIndex if
no indexing information part of input data and no index provided.
columns : Index or array-like
Column labels to use for resulting frame. Will default to
RangeIndex (0, 1, 2, ..., n) if no column labels are provided.
dtype : dtype, default None
Data type to force. Only a single dtype is allowed. If None, infer.
copy : bool, default False
Copy data from inputs. Only affects DataFrame / 2d ndarray input.
See Also
--------
DataFrame.from_records : Constructor from tuples, also record arrays.
DataFrame.from_dict : From dicts of Series, arrays, or dicts.
read_csv : Read a comma-separated values (csv) file into DataFrame.
read_table : Read general delimited file into DataFrame.
read_clipboard : Read text from clipboard into DataFrame.
Examples
--------
Constructing DataFrame from a dictionary.
>>> d = {'col1': [1, 2], 'col2': [3, 4]}
>>> df = pd.DataFrame(data=d)
>>> df
col1 col2
0 1 3
1 2 4
Notice that the inferred dtype is int64.
>>> df.dtypes
col1 int64
col2 int64
dtype: object
To enforce a single dtype:
>>> df = pd.DataFrame(data=d, dtype=np.int8)
>>> df.dtypes
col1 int8
col2 int8
dtype: object
Constructing DataFrame from numpy ndarray:
>>> df2 = pd.DataFrame(np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]]),
... columns=['a', 'b', 'c'])
>>> df2
a b c
0 1 2 3
1 4 5 6
2 7 8 9
"""
_internal_names_set = {"columns", "index"} | NDFrame._internal_names_set
_typ = "dataframe"
@property
def _constructor(self) -> Type["DataFrame"]:
return DataFrame
_constructor_sliced: Type[Series] = Series
_deprecations: FrozenSet[str] = NDFrame._deprecations | frozenset([])
_accessors: Set[str] = {"sparse"}
@property
def _constructor_expanddim(self):
raise NotImplementedError("Not supported for DataFrames!")
# ----------------------------------------------------------------------
# Constructors
def __init__(
self,
data=None,
index: Optional[Axes] = None,
columns: Optional[Axes] = None,
dtype: Optional[Dtype] = None,
copy: bool = False,
):
if data is None:
data = {}
if dtype is not None:
dtype = self._validate_dtype(dtype)
if isinstance(data, DataFrame):
data = data._data
if isinstance(data, BlockManager):
mgr = self._init_mgr(
data, axes=dict(index=index, columns=columns), dtype=dtype, copy=copy
)
elif isinstance(data, dict):
mgr = init_dict(data, index, columns, dtype=dtype)
elif isinstance(data, ma.MaskedArray):
import numpy.ma.mrecords as mrecords
# masked recarray
if isinstance(data, mrecords.MaskedRecords):
mgr = masked_rec_array_to_mgr(data, index, columns, dtype, copy)
# a masked array
else:
mask = ma.getmaskarray(data)
if mask.any():
data, fill_value = maybe_upcast(data, copy=True)
data.soften_mask() # set hardmask False if it was True
data[mask] = fill_value
else:
data = data.copy()
mgr = init_ndarray(data, index, columns, dtype=dtype, copy=copy)
elif isinstance(data, (np.ndarray, Series, Index)):
if data.dtype.names:
data_columns = list(data.dtype.names)
data = {k: data[k] for k in data_columns}
if columns is None:
columns = data_columns
mgr = init_dict(data, index, columns, dtype=dtype)
elif getattr(data, "name", None) is not None:
mgr = init_dict({data.name: data}, index, columns, dtype=dtype)
else:
mgr = init_ndarray(data, index, columns, dtype=dtype, copy=copy)
# For data is list-like, or Iterable (will consume into list)
elif isinstance(data, abc.Iterable) and not isinstance(data, (str, bytes)):
if not isinstance(data, (abc.Sequence, ExtensionArray)):
data = list(data)
if len(data) > 0:
if is_list_like(data[0]) and getattr(data[0], "ndim", 1) == 1:
if is_named_tuple(data[0]) and columns is None:
columns = data[0]._fields
arrays, columns = to_arrays(data, columns, dtype=dtype)
columns = ensure_index(columns)
# set the index
if index is None:
if isinstance(data[0], Series):
index = get_names_from_index(data)
elif isinstance(data[0], Categorical):
index = ibase.default_index(len(data[0]))
else:
index = ibase.default_index(len(data))
mgr = arrays_to_mgr(arrays, columns, index, columns, dtype=dtype)
else:
mgr = init_ndarray(data, index, columns, dtype=dtype, copy=copy)
else:
mgr = init_dict({}, index, columns, dtype=dtype)
else:
try:
arr = np.array(data, dtype=dtype, copy=copy)
except (ValueError, TypeError) as err:
exc = TypeError(
"DataFrame constructor called with "
f"incompatible data and dtype: {err}"
)
raise exc from err
if arr.ndim == 0 and index is not None and columns is not None:
values = cast_scalar_to_array(
(len(index), len(columns)), data, dtype=dtype
)
mgr = init_ndarray(
values, index, columns, dtype=values.dtype, copy=False
)
else:
raise ValueError("DataFrame constructor not properly called!")
NDFrame.__init__(self, mgr)
# ----------------------------------------------------------------------
@property
def axes(self) -> List[Index]:
"""
Return a list representing the axes of the DataFrame.
It has the row axis labels and column axis labels as the only members.
They are returned in that order.
Examples
--------
>>> df = pd.DataFrame({'col1': [1, 2], 'col2': [3, 4]})
>>> df.axes
[RangeIndex(start=0, stop=2, step=1), Index(['col1', 'col2'],
dtype='object')]
"""
return [self.index, self.columns]
@property
def shape(self) -> Tuple[int, int]:
"""
Return a tuple representing the dimensionality of the DataFrame.
See Also
--------
ndarray.shape
Examples
--------
>>> df = pd.DataFrame({'col1': [1, 2], 'col2': [3, 4]})
>>> df.shape
(2, 2)
>>> df = pd.DataFrame({'col1': [1, 2], 'col2': [3, 4],
... 'col3': [5, 6]})
>>> df.shape
(2, 3)
"""
return len(self.index), len(self.columns)
@property
def _is_homogeneous_type(self) -> bool:
"""
Whether all the columns in a DataFrame have the same type.
Returns
-------
bool
See Also
--------
Index._is_homogeneous_type : Whether the object has a single
dtype.
MultiIndex._is_homogeneous_type : Whether all the levels of a
MultiIndex have the same dtype.
Examples
--------
>>> DataFrame({"A": [1, 2], "B": [3, 4]})._is_homogeneous_type
True
>>> DataFrame({"A": [1, 2], "B": [3.0, 4.0]})._is_homogeneous_type
False
Items with the same type but different sizes are considered
different types.
>>> DataFrame({
... "A": np.array([1, 2], dtype=np.int32),
... "B": np.array([1, 2], dtype=np.int64)})._is_homogeneous_type
False
"""
if self._data.any_extension_types:
return len({block.dtype for block in self._data.blocks}) == 1
else:
return not self._data.is_mixed_type
# ----------------------------------------------------------------------
# Rendering Methods
def _repr_fits_vertical_(self) -> bool:
"""
Check length against max_rows.
"""
max_rows = get_option("display.max_rows")
return len(self) <= max_rows
def _repr_fits_horizontal_(self, ignore_width: bool = False) -> bool:
"""
Check if full repr fits in horizontal boundaries imposed by the display
options width and max_columns.
In case of non-interactive session, no boundaries apply.
`ignore_width` is here so ipnb+HTML output can behave the way
users expect. display.max_columns remains in effect.
GH3541, GH3573
"""
width, height = console.get_console_size()
max_columns = get_option("display.max_columns")
nb_columns = len(self.columns)
# exceed max columns
if (max_columns and nb_columns > max_columns) or (
(not ignore_width) and width and nb_columns > (width // 2)
):
return False
# used by repr_html under IPython notebook or scripts ignore terminal
# dims
if ignore_width or not console.in_interactive_session():
return True
if get_option("display.width") is not None or console.in_ipython_frontend():
# check at least the column row for excessive width
max_rows = 1
else:
max_rows = get_option("display.max_rows")
# when auto-detecting, so width=None and not in ipython front end
# check whether repr fits horizontal by actually checking
# the width of the rendered repr
buf = StringIO()
# only care about the stuff we'll actually print out
# and to_string on entire frame may be expensive
d = self
if not (max_rows is None): # unlimited rows
# min of two, where one may be None
d = d.iloc[: min(max_rows, len(d))]
else:
return True
d.to_string(buf=buf)
value = buf.getvalue()
repr_width = max(len(l) for l in value.split("\n"))
return repr_width < width
def _info_repr(self) -> bool:
"""
True if the repr should show the info view.
"""
info_repr_option = get_option("display.large_repr") == "info"
return info_repr_option and not (
self._repr_fits_horizontal_() and self._repr_fits_vertical_()
)
def __repr__(self) -> str:
"""
Return a string representation for a particular DataFrame.
"""
buf = StringIO("")
if self._info_repr():
self.info(buf=buf)
return buf.getvalue()
max_rows = get_option("display.max_rows")
min_rows = get_option("display.min_rows")
max_cols = get_option("display.max_columns")
max_colwidth = get_option("display.max_colwidth")
show_dimensions = get_option("display.show_dimensions")
if get_option("display.expand_frame_repr"):
width, _ = console.get_console_size()
else:
width = None
self.to_string(
buf=buf,
max_rows=max_rows,
min_rows=min_rows,
max_cols=max_cols,
line_width=width,
max_colwidth=max_colwidth,
show_dimensions=show_dimensions,
)
return buf.getvalue()
def _repr_html_(self) -> Optional[str]:
"""
Return a html representation for a particular DataFrame.
Mainly for IPython notebook.
"""
if self._info_repr():
buf = StringIO("")
self.info(buf=buf)
# need to escape the <class>, should be the first line.
val = buf.getvalue().replace("<", r"<", 1)
val = val.replace(">", r">", 1)
return "<pre>" + val + "</pre>"
if get_option("display.notebook_repr_html"):
max_rows = get_option("display.max_rows")
min_rows = get_option("display.min_rows")
max_cols = get_option("display.max_columns")
show_dimensions = get_option("display.show_dimensions")
formatter = fmt.DataFrameFormatter(
self,
columns=None,
col_space=None,
na_rep="NaN",
formatters=None,
float_format=None,
sparsify=None,
justify=None,
index_names=True,
header=True,
index=True,
bold_rows=True,
escape=True,
max_rows=max_rows,
min_rows=min_rows,
max_cols=max_cols,
show_dimensions=show_dimensions,
decimal=".",
table_id=None,
render_links=False,
)
return formatter.to_html(notebook=True)
else:
return None
@Substitution(
header_type="bool or sequence",
header="Write out the column names. If a list of strings "
"is given, it is assumed to be aliases for the "
"column names",
col_space_type="int",
col_space="The minimum width of each column",
)
@Substitution(shared_params=fmt.common_docstring, returns=fmt.return_docstring)
def to_string(
self,
buf: Optional[FilePathOrBuffer[str]] = None,
columns: Optional[Sequence[str]] = None,
col_space: Optional[int] = None,
header: Union[bool, Sequence[str]] = True,
index: bool = True,
na_rep: str = "NaN",
formatters: Optional[fmt.FormattersType] = None,
float_format: Optional[fmt.FloatFormatType] = None,
sparsify: Optional[bool] = None,
index_names: bool = True,
justify: Optional[str] = None,
max_rows: Optional[int] = None,
min_rows: Optional[int] = None,
max_cols: Optional[int] = None,
show_dimensions: bool = False,
decimal: str = ".",
line_width: Optional[int] = None,
max_colwidth: Optional[int] = None,
encoding: Optional[str] = None,
) -> Optional[str]:
"""
Render a DataFrame to a console-friendly tabular output.
%(shared_params)s
line_width : int, optional
Width to wrap a line in characters.
max_colwidth : int, optional
Max width to truncate each column in characters. By default, no limit.
.. versionadded:: 1.0.0
encoding : str, default "utf-8"
Set character encoding.
.. versionadded:: 1.0
%(returns)s
See Also
--------
to_html : Convert DataFrame to HTML.
Examples
--------
>>> d = {'col1': [1, 2, 3], 'col2': [4, 5, 6]}
>>> df = pd.DataFrame(d)
>>> print(df.to_string())
col1 col2
0 1 4
1 2 5
2 3 6
"""
from pandas import option_context
with option_context("display.max_colwidth", max_colwidth):
formatter = fmt.DataFrameFormatter(
self,
columns=columns,
col_space=col_space,
na_rep=na_rep,
formatters=formatters,
float_format=float_format,
sparsify=sparsify,
justify=justify,
index_names=index_names,
header=header,
index=index,
min_rows=min_rows,
max_rows=max_rows,
max_cols=max_cols,
show_dimensions=show_dimensions,
decimal=decimal,
line_width=line_width,
)
return formatter.to_string(buf=buf, encoding=encoding)
# ----------------------------------------------------------------------
@property
def style(self) -> "Styler":
"""
Returns a Styler object.
Contains methods for building a styled HTML representation of the DataFrame.
See Also
--------
io.formats.style.Styler
"""
from pandas.io.formats.style import Styler
return Styler(self)
_shared_docs[
"items"
] = r"""
Iterate over (column name, Series) pairs.
Iterates over the DataFrame columns, returning a tuple with
the column name and the content as a Series.
Yields
------
label : object
The column names for the DataFrame being iterated over.
content : Series
The column entries belonging to each label, as a Series.
See Also
--------
DataFrame.iterrows : Iterate over DataFrame rows as
(index, Series) pairs.
DataFrame.itertuples : Iterate over DataFrame rows as namedtuples
of the values.
Examples
--------
>>> df = pd.DataFrame({'species': ['bear', 'bear', 'marsupial'],
... 'population': [1864, 22000, 80000]},
... index=['panda', 'polar', 'koala'])
>>> df
species population
panda bear 1864
polar bear 22000
koala marsupial 80000
>>> for label, content in df.items():
... print(f'label: {label}')
... print(f'content: {content}', sep='\n')
...
label: species
content:
panda bear
polar bear
koala marsupial
Name: species, dtype: object
label: population
content:
panda 1864
polar 22000
koala 80000
Name: population, dtype: int64
"""
@Appender(_shared_docs["items"])
def items(self) -> Iterable[Tuple[Label, Series]]:
if self.columns.is_unique and hasattr(self, "_item_cache"):
for k in self.columns:
yield k, self._get_item_cache(k)
else:
for i, k in enumerate(self.columns):
yield k, self._ixs(i, axis=1)
@Appender(_shared_docs["items"])
def iteritems(self) -> Iterable[Tuple[Label, Series]]:
yield from self.items()
def iterrows(self) -> Iterable[Tuple[Label, Series]]:
"""
Iterate over DataFrame rows as (index, Series) pairs.
Yields
------
index : label or tuple of label
The index of the row. A tuple for a `MultiIndex`.
data : Series
The data of the row as a Series.
it : generator
A generator that iterates over the rows of the frame.
See Also
--------
DataFrame.itertuples : Iterate over DataFrame rows as namedtuples of the values.
DataFrame.items : Iterate over (column name, Series) pairs.
Notes
-----
1. Because ``iterrows`` returns a Series for each row,
it does **not** preserve dtypes across the rows (dtypes are
preserved across columns for DataFrames). For example,
>>> df = pd.DataFrame([[1, 1.5]], columns=['int', 'float'])
>>> row = next(df.iterrows())[1]
>>> row
int 1.0
float 1.5
Name: 0, dtype: float64
>>> print(row['int'].dtype)
float64
>>> print(df['int'].dtype)
int64
To preserve dtypes while iterating over the rows, it is better
to use :meth:`itertuples` which returns namedtuples of the values
and which is generally faster than ``iterrows``.
2. You should **never modify** something you are iterating over.
This is not guaranteed to work in all cases. Depending on the
data types, the iterator returns a copy and not a view, and writing
to it will have no effect.
"""
columns = self.columns
klass = self._constructor_sliced
for k, v in zip(self.index, self.values):
s = klass(v, index=columns, name=k)
yield k, s
def itertuples(self, index=True, name="Pandas"):
"""
Iterate over DataFrame rows as namedtuples.
Parameters
----------
index : bool, default True
If True, return the index as the first element of the tuple.
name : str or None, default "Pandas"
The name of the returned namedtuples or None to return regular
tuples.
Returns
-------
iterator
An object to iterate over namedtuples for each row in the
DataFrame with the first field possibly being the index and
following fields being the column values.
See Also
--------
DataFrame.iterrows : Iterate over DataFrame rows as (index, Series)
pairs.
DataFrame.items : Iterate over (column name, Series) pairs.
Notes
-----
The column names will be renamed to positional names if they are
invalid Python identifiers, repeated, or start with an underscore.
On python versions < 3.7 regular tuples are returned for DataFrames
with a large number of columns (>254).
Examples
--------
>>> df = pd.DataFrame({'num_legs': [4, 2], 'num_wings': [0, 2]},
... index=['dog', 'hawk'])
>>> df
num_legs num_wings
dog 4 0
hawk 2 2
>>> for row in df.itertuples():
... print(row)
...
Pandas(Index='dog', num_legs=4, num_wings=0)
Pandas(Index='hawk', num_legs=2, num_wings=2)
By setting the `index` parameter to False we can remove the index
as the first element of the tuple:
>>> for row in df.itertuples(index=False):
... print(row)
...
Pandas(num_legs=4, num_wings=0)
Pandas(num_legs=2, num_wings=2)
With the `name` parameter set we set a custom name for the yielded
namedtuples:
>>> for row in df.itertuples(name='Animal'):
... print(row)
...
Animal(Index='dog', num_legs=4, num_wings=0)
Animal(Index='hawk', num_legs=2, num_wings=2)
"""
arrays = []
fields = list(self.columns)
if index:
arrays.append(self.index)
fields.insert(0, "Index")
# use integer indexing because of possible duplicate column names
arrays.extend(self.iloc[:, k] for k in range(len(self.columns)))
# Python versions before 3.7 support at most 255 arguments to constructors
can_return_named_tuples = PY37 or len(self.columns) + index < 255
if name is not None and can_return_named_tuples:
itertuple = collections.namedtuple(name, fields, rename=True)
return map(itertuple._make, zip(*arrays))
# fallback to regular tuples
return zip(*arrays)
def __len__(self) -> int:
"""
Returns length of info axis, but here we use the index.
"""
return len(self.index)
def dot(self, other):
"""
Compute the matrix multiplication between the DataFrame and other.
This method computes the matrix product between the DataFrame and the
values of an other Series, DataFrame or a numpy array.
It can also be called using ``self @ other`` in Python >= 3.5.
Parameters
----------
other : Series, DataFrame or array-like
The other object to compute the matrix product with.
Returns
-------
Series or DataFrame
If other is a Series, return the matrix product between self and
other as a Serie. If other is a DataFrame or a numpy.array, return
the matrix product of self and other in a DataFrame of a np.array.
See Also
--------
Series.dot: Similar method for Series.
Notes
-----
The dimensions of DataFrame and other must be compatible in order to
compute the matrix multiplication. In addition, the column names of
DataFrame and the index of other must contain the same values, as they
will be aligned prior to the multiplication.
The dot method for Series computes the inner product, instead of the
matrix product here.
Examples
--------
Here we multiply a DataFrame with a Series.
>>> df = pd.DataFrame([[0, 1, -2, -1], [1, 1, 1, 1]])
>>> s = pd.Series([1, 1, 2, 1])
>>> df.dot(s)
0 -4
1 5
dtype: int64
Here we multiply a DataFrame with another DataFrame.
>>> other = pd.DataFrame([[0, 1], [1, 2], [-1, -1], [2, 0]])
>>> df.dot(other)
0 1
0 1 4
1 2 2
Note that the dot method give the same result as @
>>> df @ other
0 1
0 1 4
1 2 2
The dot method works also if other is an np.array.
>>> arr = np.array([[0, 1], [1, 2], [-1, -1], [2, 0]])
>>> df.dot(arr)
0 1
0 1 4
1 2 2
Note how shuffling of the objects does not change the result.
>>> s2 = s.reindex([1, 0, 2, 3])
>>> df.dot(s2)
0 -4
1 5
dtype: int64
"""
if isinstance(other, (Series, DataFrame)):
common = self.columns.union(other.index)
if len(common) > len(self.columns) or len(common) > len(other.index):
raise ValueError("matrices are not aligned")
left = self.reindex(columns=common, copy=False)
right = other.reindex(index=common, copy=False)
lvals = left.values
rvals = right.values
else:
left = self
lvals = self.values
rvals = np.asarray(other)
if lvals.shape[1] != rvals.shape[0]:
raise ValueError(
f"Dot product shape mismatch, {lvals.shape} vs {rvals.shape}"
)
if isinstance(other, DataFrame):
return self._constructor(
np.dot(lvals, rvals), index=left.index, columns=other.columns
)
elif isinstance(other, Series):
return Series(np.dot(lvals, rvals), index=left.index)
elif isinstance(rvals, (np.ndarray, Index)):
result = np.dot(lvals, rvals)
if result.ndim == 2:
return self._constructor(result, index=left.index)
else:
return Series(result, index=left.index)
else: # pragma: no cover
raise TypeError(f"unsupported type: {type(other)}")
def __matmul__(self, other):
"""
Matrix multiplication using binary `@` operator in Python>=3.5.
"""
return self.dot(other)
def __rmatmul__(self, other):
"""
Matrix multiplication using binary `@` operator in Python>=3.5.
"""
return self.T.dot(np.transpose(other)).T
# ----------------------------------------------------------------------
# IO methods (to / from other formats)
@classmethod
def from_dict(cls, data, orient="columns", dtype=None, columns=None) -> "DataFrame":
"""
Construct DataFrame from dict of array-like or dicts.
Creates DataFrame object from dictionary by columns or by index
allowing dtype specification.
Parameters
----------
data : dict
Of the form {field : array-like} or {field : dict}.
orient : {'columns', 'index'}, default 'columns'
The "orientation" of the data. If the keys of the passed dict
should be the columns of the resulting DataFrame, pass 'columns'
(default). Otherwise if the keys should be rows, pass 'index'.
dtype : dtype, default None
Data type to force, otherwise infer.
columns : list, default None
Column labels to use when ``orient='index'``. Raises a ValueError
if used with ``orient='columns'``.
.. versionadded:: 0.23.0
Returns
-------
DataFrame
See Also
--------
DataFrame.from_records : DataFrame from ndarray (structured
dtype), list of tuples, dict, or DataFrame.
DataFrame : DataFrame object creation using constructor.
Examples
--------
By default the keys of the dict become the DataFrame columns:
>>> data = {'col_1': [3, 2, 1, 0], 'col_2': ['a', 'b', 'c', 'd']}
>>> pd.DataFrame.from_dict(data)
col_1 col_2
0 3 a
1 2 b
2 1 c
3 0 d
Specify ``orient='index'`` to create the DataFrame using dictionary
keys as rows:
>>> data = {'row_1': [3, 2, 1, 0], 'row_2': ['a', 'b', 'c', 'd']}
>>> pd.DataFrame.from_dict(data, orient='index')
0 1 2 3
row_1 3 2 1 0
row_2 a b c d
When using the 'index' orientation, the column names can be
specified manually:
>>> pd.DataFrame.from_dict(data, orient='index',
... columns=['A', 'B', 'C', 'D'])
A B C D
row_1 3 2 1 0
row_2 a b c d
"""
index = None
orient = orient.lower()
if orient == "index":
if len(data) > 0:
# TODO speed up Series case
if isinstance(list(data.values())[0], (Series, dict)):
data = _from_nested_dict(data)
else:
data, index = list(data.values()), list(data.keys())
elif orient == "columns":
if columns is not None:
raise ValueError("cannot use columns parameter with orient='columns'")
else: # pragma: no cover
raise ValueError("only recognize index or columns for orient")
return cls(data, index=index, columns=columns, dtype=dtype)
def to_numpy(self, dtype=None, copy=False) -> np.ndarray:
"""
Convert the DataFrame to a NumPy array.
.. versionadded:: 0.24.0
By default, the dtype of the returned array will be the common NumPy
dtype of all types in the DataFrame. For example, if the dtypes are
``float16`` and ``float32``, the results dtype will be ``float32``.
This may require copying data and coercing values, which may be
expensive.
Parameters
----------
dtype : str or numpy.dtype, optional
The dtype to pass to :meth:`numpy.asarray`.
copy : bool, default False
Whether to ensure that the returned value is a not a view on
another array. Note that ``copy=False`` does not *ensure* that
``to_numpy()`` is no-copy. Rather, ``copy=True`` ensure that
a copy is made, even if not strictly necessary.
Returns
-------
numpy.ndarray
See Also
--------
Series.to_numpy : Similar method for Series.
Examples
--------
>>> pd.DataFrame({"A": [1, 2], "B": [3, 4]}).to_numpy()
array([[1, 3],
[2, 4]])
With heterogeneous data, the lowest common type will have to
be used.
>>> df = pd.DataFrame({"A": [1, 2], "B": [3.0, 4.5]})
>>> df.to_numpy()
array([[1. , 3. ],
[2. , 4.5]])
For a mix of numeric and non-numeric types, the output array will
have object dtype.
>>> df['C'] = pd.date_range('2000', periods=2)
>>> df.to_numpy()
array([[1, 3.0, Timestamp('2000-01-01 00:00:00')],
[2, 4.5, Timestamp('2000-01-02 00:00:00')]], dtype=object)
"""
result = np.array(self.values, dtype=dtype, copy=copy)
return result
def to_dict(self, orient="dict", into=dict):
"""
Convert the DataFrame to a dictionary.
The type of the key-value pairs can be customized with the parameters
(see below).
Parameters
----------
orient : str {'dict', 'list', 'series', 'split', 'records', 'index'}
Determines the type of the values of the dictionary.
- 'dict' (default) : dict like {column -> {index -> value}}
- 'list' : dict like {column -> [values]}
- 'series' : dict like {column -> Series(values)}
- 'split' : dict like
{'index' -> [index], 'columns' -> [columns], 'data' -> [values]}
- 'records' : list like
[{column -> value}, ... , {column -> value}]
- 'index' : dict like {index -> {column -> value}}
Abbreviations are allowed. `s` indicates `series` and `sp`
indicates `split`.
into : class, default dict
The collections.abc.Mapping subclass used for all Mappings
in the return value. Can be the actual class or an empty
instance of the mapping type you want. If you want a
collections.defaultdict, you must pass it initialized.
.. versionadded:: 0.21.0
Returns
-------
dict, list or collections.abc.Mapping
Return a collections.abc.Mapping object representing the DataFrame.
The resulting transformation depends on the `orient` parameter.
See Also
--------
DataFrame.from_dict: Create a DataFrame from a dictionary.
DataFrame.to_json: Convert a DataFrame to JSON format.
Examples
--------
>>> df = pd.DataFrame({'col1': [1, 2],
... 'col2': [0.5, 0.75]},
... index=['row1', 'row2'])
>>> df
col1 col2
row1 1 0.50
row2 2 0.75
>>> df.to_dict()
{'col1': {'row1': 1, 'row2': 2}, 'col2': {'row1': 0.5, 'row2': 0.75}}
You can specify the return orientation.
>>> df.to_dict('series')
{'col1': row1 1
row2 2
Name: col1, dtype: int64,
'col2': row1 0.50
row2 0.75
Name: col2, dtype: float64}
>>> df.to_dict('split')
{'index': ['row1', 'row2'], 'columns': ['col1', 'col2'],
'data': [[1, 0.5], [2, 0.75]]}
>>> df.to_dict('records')
[{'col1': 1, 'col2': 0.5}, {'col1': 2, 'col2': 0.75}]
>>> df.to_dict('index')
{'row1': {'col1': 1, 'col2': 0.5}, 'row2': {'col1': 2, 'col2': 0.75}}
You can also specify the mapping type.
>>> from collections import OrderedDict, defaultdict
>>> df.to_dict(into=OrderedDict)
OrderedDict([('col1', OrderedDict([('row1', 1), ('row2', 2)])),
('col2', OrderedDict([('row1', 0.5), ('row2', 0.75)]))])
If you want a `defaultdict`, you need to initialize it:
>>> dd = defaultdict(list)
>>> df.to_dict('records', into=dd)
[defaultdict(<class 'list'>, {'col1': 1, 'col2': 0.5}),
defaultdict(<class 'list'>, {'col1': 2, 'col2': 0.75})]
"""
if not self.columns.is_unique:
warnings.warn(
"DataFrame columns are not unique, some columns will be omitted.",
UserWarning,
stacklevel=2,
)
# GH16122
into_c = com.standardize_mapping(into)
if orient.lower().startswith("d"):
return into_c((k, v.to_dict(into)) for k, v in self.items())
elif orient.lower().startswith("l"):
return into_c((k, v.tolist()) for k, v in self.items())
elif orient.lower().startswith("sp"):
return into_c(
(
("index", self.index.tolist()),
("columns", self.columns.tolist()),
(
"data",
[
list(map(com.maybe_box_datetimelike, t))
for t in self.itertuples(index=False, name=None)
],
),
)
)
elif orient.lower().startswith("s"):
return into_c((k, com.maybe_box_datetimelike(v)) for k, v in self.items())
elif orient.lower().startswith("r"):
columns = self.columns.tolist()
rows = (
dict(zip(columns, row))
for row in self.itertuples(index=False, name=None)
)
return [
into_c((k, com.maybe_box_datetimelike(v)) for k, v in row.items())
for row in rows
]
elif orient.lower().startswith("i"):
if not self.index.is_unique:
raise ValueError("DataFrame index must be unique for orient='index'.")
return into_c(
(t[0], dict(zip(self.columns, t[1:])))
for t in self.itertuples(name=None)
)
else:
raise ValueError(f"orient '{orient}' not understood")
def to_gbq(
self,
destination_table,
project_id=None,
chunksize=None,
reauth=False,
if_exists="fail",
auth_local_webserver=False,
table_schema=None,
location=None,
progress_bar=True,
credentials=None,
) -> None:
"""
Write a DataFrame to a Google BigQuery table.
This function requires the `pandas-gbq package
<https://pandas-gbq.readthedocs.io>`__.
See the `How to authenticate with Google BigQuery
<https://pandas-gbq.readthedocs.io/en/latest/howto/authentication.html>`__
guide for authentication instructions.
Parameters
----------
destination_table : str
Name of table to be written, in the form ``dataset.tablename``.
project_id : str, optional
Google BigQuery Account project ID. Optional when available from
the environment.
chunksize : int, optional
Number of rows to be inserted in each chunk from the dataframe.
Set to ``None`` to load the whole dataframe at once.
reauth : bool, default False
Force Google BigQuery to re-authenticate the user. This is useful
if multiple accounts are used.
if_exists : str, default 'fail'
Behavior when the destination table exists. Value can be one of:
``'fail'``
If table exists raise pandas_gbq.gbq.TableCreationError.
``'replace'``
If table exists, drop it, recreate it, and insert data.
``'append'``
If table exists, insert data. Create if does not exist.
auth_local_webserver : bool, default False
Use the `local webserver flow`_ instead of the `console flow`_
when getting user credentials.
.. _local webserver flow:
https://google-auth-oauthlib.readthedocs.io/en/latest/reference/google_auth_oauthlib.flow.html#google_auth_oauthlib.flow.InstalledAppFlow.run_local_server
.. _console flow:
https://google-auth-oauthlib.readthedocs.io/en/latest/reference/google_auth_oauthlib.flow.html#google_auth_oauthlib.flow.InstalledAppFlow.run_console
*New in version 0.2.0 of pandas-gbq*.
table_schema : list of dicts, optional
List of BigQuery table fields to which according DataFrame
columns conform to, e.g. ``[{'name': 'col1', 'type':
'STRING'},...]``. If schema is not provided, it will be
generated according to dtypes of DataFrame columns. See
BigQuery API documentation on available names of a field.
*New in version 0.3.1 of pandas-gbq*.
location : str, optional
Location where the load job should run. See the `BigQuery locations
documentation
<https://cloud.google.com/bigquery/docs/dataset-locations>`__ for a
list of available locations. The location must match that of the
target dataset.
*New in version 0.5.0 of pandas-gbq*.
progress_bar : bool, default True
Use the library `tqdm` to show the progress bar for the upload,
chunk by chunk.
*New in version 0.5.0 of pandas-gbq*.
credentials : google.auth.credentials.Credentials, optional
Credentials for accessing Google APIs. Use this parameter to
override default credentials, such as to use Compute Engine
:class:`google.auth.compute_engine.Credentials` or Service
Account :class:`google.oauth2.service_account.Credentials`
directly.
*New in version 0.8.0 of pandas-gbq*.
.. versionadded:: 0.24.0
See Also
--------
pandas_gbq.to_gbq : This function in the pandas-gbq library.
read_gbq : Read a DataFrame from Google BigQuery.
"""
from pandas.io import gbq
gbq.to_gbq(
self,
destination_table,
project_id=project_id,
chunksize=chunksize,
reauth=reauth,
if_exists=if_exists,
auth_local_webserver=auth_local_webserver,
table_schema=table_schema,
location=location,
progress_bar=progress_bar,
credentials=credentials,
)
@classmethod
def from_records(
cls,
data,
index=None,
exclude=None,
columns=None,
coerce_float=False,
nrows=None,
) -> "DataFrame":
"""
Convert structured or record ndarray to DataFrame.
Parameters
----------
data : ndarray (structured dtype), list of tuples, dict, or DataFrame
index : str, list of fields, array-like
Field of array to use as the index, alternately a specific set of
input labels to use.
exclude : sequence, default None
Columns or fields to exclude.
columns : sequence, default None
Column names to use. If the passed data do not have names
associated with them, this argument provides names for the
columns. Otherwise this argument indicates the order of the columns
in the result (any names not found in the data will become all-NA
columns).
coerce_float : bool, default False
Attempt to convert values of non-string, non-numeric objects (like
decimal.Decimal) to floating point, useful for SQL result sets.
nrows : int, default None
Number of rows to read if data is an iterator.
Returns
-------
DataFrame
"""
# Make a copy of the input columns so we can modify it
if columns is not None:
columns = ensure_index(columns)
if is_iterator(data):
if nrows == 0:
return cls()
try:
first_row = next(data)
except StopIteration:
return cls(index=index, columns=columns)
dtype = None
if hasattr(first_row, "dtype") and first_row.dtype.names:
dtype = first_row.dtype
values = [first_row]
if nrows is None:
values += data
else:
values.extend(itertools.islice(data, nrows - 1))
if dtype is not None:
data = np.array(values, dtype=dtype)
else:
data = values
if isinstance(data, dict):
if columns is None:
columns = arr_columns = ensure_index(sorted(data))
arrays = [data[k] for k in columns]
else:
arrays = []
arr_columns = []
for k, v in data.items():
if k in columns:
arr_columns.append(k)
arrays.append(v)
arrays, arr_columns = reorder_arrays(arrays, arr_columns, columns)
elif isinstance(data, (np.ndarray, DataFrame)):
arrays, columns = to_arrays(data, columns)
if columns is not None:
columns = ensure_index(columns)
arr_columns = columns
else:
arrays, arr_columns = to_arrays(data, columns, coerce_float=coerce_float)
arr_columns = ensure_index(arr_columns)
if columns is not None:
columns = ensure_index(columns)
else:
columns = arr_columns
if exclude is None:
exclude = set()
else:
exclude = set(exclude)
result_index = None
if index is not None:
if isinstance(index, str) or not hasattr(index, "__iter__"):
i = columns.get_loc(index)
exclude.add(index)
if len(arrays) > 0:
result_index = Index(arrays[i], name=index)
else:
result_index = Index([], name=index)
else:
try:
index_data = [arrays[arr_columns.get_loc(field)] for field in index]
except (KeyError, TypeError):
# raised by get_loc, see GH#29258
result_index = index
else:
result_index = ensure_index_from_sequences(index_data, names=index)
exclude.update(index)
if any(exclude):
arr_exclude = [x for x in exclude if x in arr_columns]
to_remove = [arr_columns.get_loc(col) for col in arr_exclude]
arrays = [v for i, v in enumerate(arrays) if i not in to_remove]
arr_columns = arr_columns.drop(arr_exclude)
columns = columns.drop(exclude)
mgr = arrays_to_mgr(arrays, arr_columns, result_index, columns)
return cls(mgr)
def to_records(
self, index=True, column_dtypes=None, index_dtypes=None
) -> np.recarray:
"""
Convert DataFrame to a NumPy record array.
Index will be included as the first field of the record array if
requested.
Parameters
----------
index : bool, default True
Include index in resulting record array, stored in 'index'
field or using the index label, if set.
column_dtypes : str, type, dict, default None
.. versionadded:: 0.24.0
If a string or type, the data type to store all columns. If
a dictionary, a mapping of column names and indices (zero-indexed)
to specific data types.
index_dtypes : str, type, dict, default None
.. versionadded:: 0.24.0
If a string or type, the data type to store all index levels. If
a dictionary, a mapping of index level names and indices
(zero-indexed) to specific data types.
This mapping is applied only if `index=True`.
Returns
-------
numpy.recarray
NumPy ndarray with the DataFrame labels as fields and each row
of the DataFrame as entries.
See Also
--------
DataFrame.from_records: Convert structured or record ndarray
to DataFrame.
numpy.recarray: An ndarray that allows field access using
attributes, analogous to typed columns in a
spreadsheet.
Examples
--------
>>> df = pd.DataFrame({'A': [1, 2], 'B': [0.5, 0.75]},
... index=['a', 'b'])
>>> df
A B
a 1 0.50
b 2 0.75
>>> df.to_records()
rec.array([('a', 1, 0.5 ), ('b', 2, 0.75)],
dtype=[('index', 'O'), ('A', '<i8'), ('B', '<f8')])
If the DataFrame index has no label then the recarray field name
is set to 'index'. If the index has a label then this is used as the
field name:
>>> df.index = df.index.rename("I")
>>> df.to_records()
rec.array([('a', 1, 0.5 ), ('b', 2, 0.75)],
dtype=[('I', 'O'), ('A', '<i8'), ('B', '<f8')])
The index can be excluded from the record array:
>>> df.to_records(index=False)
rec.array([(1, 0.5 ), (2, 0.75)],
dtype=[('A', '<i8'), ('B', '<f8')])
Data types can be specified for the columns:
>>> df.to_records(column_dtypes={"A": "int32"})
rec.array([('a', 1, 0.5 ), ('b', 2, 0.75)],
dtype=[('I', 'O'), ('A', '<i4'), ('B', '<f8')])
As well as for the index:
>>> df.to_records(index_dtypes="<S2")
rec.array([(b'a', 1, 0.5 ), (b'b', 2, 0.75)],
dtype=[('I', 'S2'), ('A', '<i8'), ('B', '<f8')])
>>> index_dtypes = f"<S{df.index.str.len().max()}"
>>> df.to_records(index_dtypes=index_dtypes)
rec.array([(b'a', 1, 0.5 ), (b'b', 2, 0.75)],
dtype=[('I', 'S1'), ('A', '<i8'), ('B', '<f8')])
"""
if index:
if isinstance(self.index, ABCMultiIndex):
# array of tuples to numpy cols. copy copy copy
ix_vals = list(map(np.array, zip(*self.index.values)))
else:
ix_vals = [self.index.values]
arrays = ix_vals + [self[c]._internal_get_values() for c in self.columns]
count = 0
index_names = list(self.index.names)
if isinstance(self.index, ABCMultiIndex):
for i, n in enumerate(index_names):
if n is None:
index_names[i] = f"level_{count}"
count += 1
elif index_names[0] is None:
index_names = ["index"]
names = [str(name) for name in itertools.chain(index_names, self.columns)]
else:
arrays = [self[c]._internal_get_values() for c in self.columns]
names = [str(c) for c in self.columns]
index_names = []
index_len = len(index_names)
formats = []
for i, v in enumerate(arrays):
index = i
# When the names and arrays are collected, we
# first collect those in the DataFrame's index,
# followed by those in its columns.
#
# Thus, the total length of the array is:
# len(index_names) + len(DataFrame.columns).
#
# This check allows us to see whether we are
# handling a name / array in the index or column.
if index < index_len:
dtype_mapping = index_dtypes
name = index_names[index]
else:
index -= index_len
dtype_mapping = column_dtypes
name = self.columns[index]
# We have a dictionary, so we get the data type
# associated with the index or column (which can
# be denoted by its name in the DataFrame or its
# position in DataFrame's array of indices or
# columns, whichever is applicable.
if is_dict_like(dtype_mapping):
if name in dtype_mapping:
dtype_mapping = dtype_mapping[name]
elif index in dtype_mapping:
dtype_mapping = dtype_mapping[index]
else:
dtype_mapping = None
# If no mapping can be found, use the array's
# dtype attribute for formatting.
#
# A valid dtype must either be a type or
# string naming a type.
if dtype_mapping is None:
formats.append(v.dtype)
elif isinstance(dtype_mapping, (type, np.dtype, str)):
formats.append(dtype_mapping)
else:
element = "row" if i < index_len else "column"
msg = f"Invalid dtype {dtype_mapping} specified for {element} {name}"
raise ValueError(msg)
return np.rec.fromarrays(arrays, dtype={"names": names, "formats": formats})
@classmethod
def _from_arrays(cls, arrays, columns, index, dtype=None) -> "DataFrame":
mgr = arrays_to_mgr(arrays, columns, index, columns, dtype=dtype)
return cls(mgr)
@deprecate_kwarg(old_arg_name="fname", new_arg_name="path")
def to_stata(
self,
path: FilePathOrBuffer,
convert_dates: Optional[Dict[Label, str]] = None,
write_index: bool = True,
byteorder: Optional[str] = None,
time_stamp: Optional[datetime.datetime] = None,
data_label: Optional[str] = None,
variable_labels: Optional[Dict[Label, str]] = None,
version: Optional[int] = 114,
convert_strl: Optional[Sequence[Label]] = None,
) -> None:
"""
Export DataFrame object to Stata dta format.
Writes the DataFrame to a Stata dataset file.
"dta" files contain a Stata dataset.
Parameters
----------
path : str, buffer or path object
String, path object (pathlib.Path or py._path.local.LocalPath) or
object implementing a binary write() function. If using a buffer
then the buffer will not be automatically closed after the file
data has been written.
.. versionchanged:: 1.0.0
Previously this was "fname"
convert_dates : dict
Dictionary mapping columns containing datetime types to stata
internal format to use when writing the dates. Options are 'tc',
'td', 'tm', 'tw', 'th', 'tq', 'ty'. Column can be either an integer
or a name. Datetime columns that do not have a conversion type
specified will be converted to 'tc'. Raises NotImplementedError if
a datetime column has timezone information.
write_index : bool
Write the index to Stata dataset.
byteorder : str
Can be ">", "<", "little", or "big". default is `sys.byteorder`.
time_stamp : datetime
A datetime to use as file creation date. Default is the current
time.
data_label : str, optional
A label for the data set. Must be 80 characters or smaller.
variable_labels : dict
Dictionary containing columns as keys and variable labels as
values. Each label must be 80 characters or smaller.
version : {114, 117, 118, 119, None}, default 114
Version to use in the output dta file. Set to None to let pandas
decide between 118 or 119 formats depending on the number of
columns in the frame. Version 114 can be read by Stata 10 and
later. Version 117 can be read by Stata 13 or later. Version 118
is supported in Stata 14 and later. Version 119 is supported in
Stata 15 and later. Version 114 limits string variables to 244
characters or fewer while versions 117 and later allow strings
with lengths up to 2,000,000 characters. Versions 118 and 119
support Unicode characters, and version 119 supports more than
32,767 variables.
.. versionadded:: 0.23.0
.. versionchanged:: 1.0.0
Added support for formats 118 and 119.
convert_strl : list, optional
List of column names to convert to string columns to Stata StrL
format. Only available if version is 117. Storing strings in the
StrL format can produce smaller dta files if strings have more than
8 characters and values are repeated.
.. versionadded:: 0.23.0
Raises
------
NotImplementedError
* If datetimes contain timezone information
* Column dtype is not representable in Stata
ValueError
* Columns listed in convert_dates are neither datetime64[ns]
or datetime.datetime
* Column listed in convert_dates is not in DataFrame
* Categorical label contains more than 32,000 characters
See Also
--------
read_stata : Import Stata data files.
io.stata.StataWriter : Low-level writer for Stata data files.
io.stata.StataWriter117 : Low-level writer for version 117 files.
Examples
--------
>>> df = pd.DataFrame({'animal': ['falcon', 'parrot', 'falcon',
... 'parrot'],
... 'speed': [350, 18, 361, 15]})
>>> df.to_stata('animals.dta') # doctest: +SKIP
"""
if version not in (114, 117, 118, 119, None):
raise ValueError("Only formats 114, 117, 118 and 119 are supported.")
if version == 114:
if convert_strl is not None:
raise ValueError("strl is not supported in format 114")
from pandas.io.stata import StataWriter as statawriter
elif version == 117:
# mypy: Name 'statawriter' already defined (possibly by an import)
from pandas.io.stata import StataWriter117 as statawriter # type: ignore
else: # versions 118 and 119
# mypy: Name 'statawriter' already defined (possibly by an import)
from pandas.io.stata import StataWriterUTF8 as statawriter # type:ignore
kwargs: Dict[str, Any] = {}
if version is None or version >= 117:
# strl conversion is only supported >= 117
kwargs["convert_strl"] = convert_strl
if version is None or version >= 118:
# Specifying the version is only supported for UTF8 (118 or 119)
kwargs["version"] = version
# mypy: Too many arguments for "StataWriter"
writer = statawriter( # type: ignore
path,
self,
convert_dates=convert_dates,
byteorder=byteorder,
time_stamp=time_stamp,
data_label=data_label,
write_index=write_index,
variable_labels=variable_labels,
**kwargs,
)
writer.write_file()
@deprecate_kwarg(old_arg_name="fname", new_arg_name="path")
def to_feather(self, path) -> None:
"""
Write out the binary feather-format for DataFrames.
Parameters
----------
path : str
String file path.
"""
from pandas.io.feather_format import to_feather
to_feather(self, path)
@Appender(
"""
Examples
--------
>>> df = pd.DataFrame(
... data={"animal_1": ["elk", "pig"], "animal_2": ["dog", "quetzal"]}
... )
>>> print(df.to_markdown())
| | animal_1 | animal_2 |
|---:|:-----------|:-----------|
| 0 | elk | dog |
| 1 | pig | quetzal |
"""
)
@Substitution(klass="DataFrame")
@Appender(_shared_docs["to_markdown"])
def to_markdown(
self, buf: Optional[IO[str]] = None, mode: Optional[str] = None, **kwargs
) -> Optional[str]:
kwargs.setdefault("headers", "keys")
kwargs.setdefault("tablefmt", "pipe")
tabulate = import_optional_dependency("tabulate")
result = tabulate.tabulate(self, **kwargs)
if buf is None:
return result
buf, _, _, _ = get_filepath_or_buffer(buf, mode=mode)
assert buf is not None # Help mypy.
buf.writelines(result)
return None
@deprecate_kwarg(old_arg_name="fname", new_arg_name="path")
def to_parquet(
self,
path,
engine="auto",
compression="snappy",
index=None,
partition_cols=None,
**kwargs,
) -> None:
"""
Write a DataFrame to the binary parquet format.
.. versionadded:: 0.21.0
This function writes the dataframe as a `parquet file
<https://parquet.apache.org/>`_. You can choose different parquet
backends, and have the option of compression. See
:ref:`the user guide <io.parquet>` for more details.
Parameters
----------
path : str
File path or Root Directory path. Will be used as Root Directory
path while writing a partitioned dataset.
.. versionchanged:: 1.0.0
Previously this was "fname"
engine : {'auto', 'pyarrow', 'fastparquet'}, default 'auto'
Parquet library to use. If 'auto', then the option
``io.parquet.engine`` is used. The default ``io.parquet.engine``
behavior is to try 'pyarrow', falling back to 'fastparquet' if
'pyarrow' is unavailable.
compression : {'snappy', 'gzip', 'brotli', None}, default 'snappy'
Name of the compression to use. Use ``None`` for no compression.
index : bool, default None
If ``True``, include the dataframe's index(es) in the file output.
If ``False``, they will not be written to the file.
If ``None``, similar to ``True`` the dataframe's index(es)
will be saved. However, instead of being saved as values,
the RangeIndex will be stored as a range in the metadata so it
doesn't require much space and is faster. Other indexes will
be included as columns in the file output.
.. versionadded:: 0.24.0
partition_cols : list, optional, default None
Column names by which to partition the dataset.
Columns are partitioned in the order they are given.
.. versionadded:: 0.24.0
**kwargs
Additional arguments passed to the parquet library. See
:ref:`pandas io <io.parquet>` for more details.
See Also
--------
read_parquet : Read a parquet file.
DataFrame.to_csv : Write a csv file.
DataFrame.to_sql : Write to a sql table.
DataFrame.to_hdf : Write to hdf.
Notes
-----
This function requires either the `fastparquet
<https://pypi.org/project/fastparquet>`_ or `pyarrow
<https://arrow.apache.org/docs/python/>`_ library.
Examples
--------
>>> df = pd.DataFrame(data={'col1': [1, 2], 'col2': [3, 4]})
>>> df.to_parquet('df.parquet.gzip',
... compression='gzip') # doctest: +SKIP
>>> pd.read_parquet('df.parquet.gzip') # doctest: +SKIP
col1 col2
0 1 3
1 2 4
"""
from pandas.io.parquet import to_parquet
to_parquet(
self,
path,
engine,
compression=compression,
index=index,
partition_cols=partition_cols,
**kwargs,
)
@Substitution(
header_type="bool",
header="Whether to print column labels, default True",
col_space_type="str or int",
col_space="The minimum width of each column in CSS length "
"units. An int is assumed to be px units.\n\n"
" .. versionadded:: 0.25.0\n"
" Ability to use str",
)
@Substitution(shared_params=fmt.common_docstring, returns=fmt.return_docstring)
def to_html(
self,
buf=None,
columns=None,
col_space=None,
header=True,
index=True,
na_rep="NaN",
formatters=None,
float_format=None,
sparsify=None,
index_names=True,
justify=None,
max_rows=None,
max_cols=None,
show_dimensions=False,
decimal=".",
bold_rows=True,
classes=None,
escape=True,
notebook=False,
border=None,
table_id=None,
render_links=False,
encoding=None,
):
"""
Render a DataFrame as an HTML table.
%(shared_params)s
bold_rows : bool, default True
Make the row labels bold in the output.
classes : str or list or tuple, default None
CSS class(es) to apply to the resulting html table.
escape : bool, default True
Convert the characters <, >, and & to HTML-safe sequences.
notebook : {True, False}, default False
Whether the generated HTML is for IPython Notebook.
border : int
A ``border=border`` attribute is included in the opening
`<table>` tag. Default ``pd.options.display.html.border``.
encoding : str, default "utf-8"
Set character encoding.
.. versionadded:: 1.0
table_id : str, optional
A css id is included in the opening `<table>` tag if specified.
.. versionadded:: 0.23.0
render_links : bool, default False
Convert URLs to HTML links.
.. versionadded:: 0.24.0
%(returns)s
See Also
--------
to_string : Convert DataFrame to a string.
"""
if justify is not None and justify not in fmt._VALID_JUSTIFY_PARAMETERS:
raise ValueError("Invalid value for justify parameter")
formatter = fmt.DataFrameFormatter(
self,
columns=columns,
col_space=col_space,
na_rep=na_rep,
formatters=formatters,
float_format=float_format,
sparsify=sparsify,
justify=justify,
index_names=index_names,
header=header,
index=index,
bold_rows=bold_rows,
escape=escape,
max_rows=max_rows,
max_cols=max_cols,
show_dimensions=show_dimensions,
decimal=decimal,
table_id=table_id,
render_links=render_links,
)
# TODO: a generic formatter wld b in DataFrameFormatter
return formatter.to_html(
buf=buf,
classes=classes,
notebook=notebook,
border=border,
encoding=encoding,
)
# ----------------------------------------------------------------------
@Appender(info.__doc__)
def info(
self, verbose=None, buf=None, max_cols=None, memory_usage=None, null_counts=None
) -> None:
return info(self, verbose, buf, max_cols, memory_usage, null_counts)
def memory_usage(self, index=True, deep=False) -> Series:
"""
Return the memory usage of each column in bytes.
The memory usage can optionally include the contribution of
the index and elements of `object` dtype.
This value is displayed in `DataFrame.info` by default. This can be
suppressed by setting ``pandas.options.display.memory_usage`` to False.
Parameters
----------
index : bool, default True
Specifies whether to include the memory usage of the DataFrame's
index in returned Series. If ``index=True``, the memory usage of
the index is the first item in the output.
deep : bool, default False
If True, introspect the data deeply by interrogating
`object` dtypes for system-level memory consumption, and include
it in the returned values.
Returns
-------
Series
A Series whose index is the original column names and whose values
is the memory usage of each column in bytes.
See Also
--------
numpy.ndarray.nbytes : Total bytes consumed by the elements of an
ndarray.
Series.memory_usage : Bytes consumed by a Series.
Categorical : Memory-efficient array for string values with
many repeated values.
DataFrame.info : Concise summary of a DataFrame.
Examples
--------
>>> dtypes = ['int64', 'float64', 'complex128', 'object', 'bool']
>>> data = dict([(t, np.ones(shape=5000).astype(t))
... for t in dtypes])
>>> df = pd.DataFrame(data)
>>> df.head()
int64 float64 complex128 object bool
0 1 1.0 1.000000+0.000000j 1 True
1 1 1.0 1.000000+0.000000j 1 True
2 1 1.0 1.000000+0.000000j 1 True
3 1 1.0 1.000000+0.000000j 1 True
4 1 1.0 1.000000+0.000000j 1 True
>>> df.memory_usage()
Index 128
int64 40000
float64 40000
complex128 80000
object 40000
bool 5000
dtype: int64
>>> df.memory_usage(index=False)
int64 40000
float64 40000
complex128 80000
object 40000
bool 5000
dtype: int64
The memory footprint of `object` dtype columns is ignored by default:
>>> df.memory_usage(deep=True)
Index 128
int64 40000
float64 40000
complex128 80000
object 160000
bool 5000
dtype: int64
Use a Categorical for efficient storage of an object-dtype column with
many repeated values.
>>> df['object'].astype('category').memory_usage(deep=True)
5216
"""
result = Series(
[c.memory_usage(index=False, deep=deep) for col, c in self.items()],
index=self.columns,
)
if index:
result = Series(self.index.memory_usage(deep=deep), index=["Index"]).append(
result
)
return result
def transpose(self, *args, copy: bool = False) -> "DataFrame":
"""
Transpose index and columns.
Reflect the DataFrame over its main diagonal by writing rows as columns
and vice-versa. The property :attr:`.T` is an accessor to the method
:meth:`transpose`.
Parameters
----------
*args : tuple, optional
Accepted for compatibility with NumPy.
copy : bool, default False
Whether to copy the data after transposing, even for DataFrames
with a single dtype.
Note that a copy is always required for mixed dtype DataFrames,
or for DataFrames with any extension types.
Returns
-------
DataFrame
The transposed DataFrame.
See Also
--------
numpy.transpose : Permute the dimensions of a given array.
Notes
-----
Transposing a DataFrame with mixed dtypes will result in a homogeneous
DataFrame with the `object` dtype. In such a case, a copy of the data
is always made.
Examples
--------
**Square DataFrame with homogeneous dtype**
>>> d1 = {'col1': [1, 2], 'col2': [3, 4]}
>>> df1 = pd.DataFrame(data=d1)
>>> df1
col1 col2
0 1 3
1 2 4
>>> df1_transposed = df1.T # or df1.transpose()
>>> df1_transposed
0 1
col1 1 2
col2 3 4
When the dtype is homogeneous in the original DataFrame, we get a
transposed DataFrame with the same dtype:
>>> df1.dtypes
col1 int64
col2 int64
dtype: object
>>> df1_transposed.dtypes
0 int64
1 int64
dtype: object
**Non-square DataFrame with mixed dtypes**
>>> d2 = {'name': ['Alice', 'Bob'],
... 'score': [9.5, 8],
... 'employed': [False, True],
... 'kids': [0, 0]}
>>> df2 = pd.DataFrame(data=d2)
>>> df2
name score employed kids
0 Alice 9.5 False 0
1 Bob 8.0 True 0
>>> df2_transposed = df2.T # or df2.transpose()
>>> df2_transposed
0 1
name Alice Bob
score 9.5 8
employed False True
kids 0 0
When the DataFrame has mixed dtypes, we get a transposed DataFrame with
the `object` dtype:
>>> df2.dtypes
name object
score float64
employed bool
kids int64
dtype: object
>>> df2_transposed.dtypes
0 object
1 object
dtype: object
"""
nv.validate_transpose(args, dict())
# construct the args
dtypes = list(self.dtypes)
if self._is_homogeneous_type and dtypes and is_extension_array_dtype(dtypes[0]):
# We have EAs with the same dtype. We can preserve that dtype in transpose.
dtype = dtypes[0]
arr_type = dtype.construct_array_type()
values = self.values
new_values = [arr_type._from_sequence(row, dtype=dtype) for row in values]
result = self._constructor(
dict(zip(self.index, new_values)), index=self.columns
)
else:
new_values = self.values.T
if copy:
new_values = new_values.copy()
result = self._constructor(
new_values, index=self.columns, columns=self.index
)
return result.__finalize__(self)
@property
def T(self) -> "DataFrame":
return self.transpose()
# ----------------------------------------------------------------------
# Indexing Methods
def _ixs(self, i: int, axis: int = 0):
"""
Parameters
----------
i : int
axis : int
Notes
-----
If slice passed, the resulting data will be a view.
"""
# irow
if axis == 0:
new_values = self._data.fast_xs(i)
# if we are a copy, mark as such
copy = isinstance(new_values, np.ndarray) and new_values.base is None
result = self._constructor_sliced(
new_values,
index=self.columns,
name=self.index[i],
dtype=new_values.dtype,
)
result._set_is_copy(self, copy=copy)
return result
# icol
else:
label = self.columns[i]
values = self._data.iget(i)
result = self._box_col_values(values, label)
# this is a cached value, mark it so
result._set_as_cached(label, self)
return result
def __getitem__(self, key):
key = lib.item_from_zerodim(key)
key = com.apply_if_callable(key, self)
if is_hashable(key):
# shortcut if the key is in columns
if self.columns.is_unique and key in self.columns:
if self.columns.nlevels > 1:
return self._getitem_multilevel(key)
return self._get_item_cache(key)
# Do we have a slicer (on rows)?
indexer = convert_to_index_sliceable(self, key)
if indexer is not None:
# either we have a slice or we have a string that can be converted
# to a slice for partial-string date indexing
return self._slice(indexer, axis=0)
# Do we have a (boolean) DataFrame?
if isinstance(key, DataFrame):
return self.where(key)
# Do we have a (boolean) 1d indexer?
if com.is_bool_indexer(key):
return self._getitem_bool_array(key)
# We are left with two options: a single key, and a collection of keys,
# We interpret tuples as collections only for non-MultiIndex
is_single_key = isinstance(key, tuple) or not is_list_like(key)
if is_single_key:
if self.columns.nlevels > 1:
return self._getitem_multilevel(key)
indexer = self.columns.get_loc(key)
if is_integer(indexer):
indexer = [indexer]
else:
if is_iterator(key):
key = list(key)
indexer = self.loc._get_listlike_indexer(key, axis=1, raise_missing=True)[1]
# take() does not accept boolean indexers
if getattr(indexer, "dtype", None) == bool:
indexer = np.where(indexer)[0]
data = self._take_with_is_copy(indexer, axis=1)
if is_single_key:
# What does looking for a single key in a non-unique index return?
# The behavior is inconsistent. It returns a Series, except when
# - the key itself is repeated (test on data.shape, #9519), or
# - we have a MultiIndex on columns (test on self.columns, #21309)
if data.shape[1] == 1 and not isinstance(self.columns, ABCMultiIndex):
data = data[key]
return data
def _getitem_bool_array(self, key):
# also raises Exception if object array with NA values
# warning here just in case -- previously __setitem__ was
# reindexing but __getitem__ was not; it seems more reasonable to
# go with the __setitem__ behavior since that is more consistent
# with all other indexing behavior
if isinstance(key, Series) and not key.index.equals(self.index):
warnings.warn(
"Boolean Series key will be reindexed to match DataFrame index.",
UserWarning,
stacklevel=3,
)
elif len(key) != len(self.index):
raise ValueError(
f"Item wrong length {len(key)} instead of {len(self.index)}."
)
# check_bool_indexer will throw exception if Series key cannot
# be reindexed to match DataFrame rows
key = check_bool_indexer(self.index, key)
indexer = key.nonzero()[0]
return self._take_with_is_copy(indexer, axis=0)
def _getitem_multilevel(self, key):
# self.columns is a MultiIndex
loc = self.columns.get_loc(key)
if isinstance(loc, (slice, Series, np.ndarray, Index)):
new_columns = self.columns[loc]
result_columns = maybe_droplevels(new_columns, key)
if self._is_mixed_type:
result = self.reindex(columns=new_columns)
result.columns = result_columns
else:
new_values = self.values[:, loc]
result = self._constructor(
new_values, index=self.index, columns=result_columns
)
result = result.__finalize__(self)
# If there is only one column being returned, and its name is
# either an empty string, or a tuple with an empty string as its
# first element, then treat the empty string as a placeholder
# and return the column as if the user had provided that empty
# string in the key. If the result is a Series, exclude the
# implied empty string from its name.
if len(result.columns) == 1:
top = result.columns[0]
if isinstance(top, tuple):
top = top[0]
if top == "":
result = result[""]
if isinstance(result, Series):
result = self._constructor_sliced(
result, index=self.index, name=key
)
result._set_is_copy(self)
return result
else:
return self._get_item_cache(key)
def _get_value(self, index, col, takeable: bool = False):
"""
Quickly retrieve single value at passed column and index.
Parameters
----------
index : row label
col : column label
takeable : interpret the index/col as indexers, default False
Returns
-------
scalar
"""
if takeable:
series = self._ixs(col, axis=1)
return series._values[index]
series = self._get_item_cache(col)
engine = self.index._engine
try:
loc = engine.get_loc(index)
return series._values[loc]
except KeyError:
# GH 20629
if self.index.nlevels > 1:
# partial indexing forbidden
raise
# we cannot handle direct indexing
# use positional
col = self.columns.get_loc(col)
index = self.index.get_loc(index)
return self._get_value(index, col, takeable=True)
def __setitem__(self, key, value):
key = com.apply_if_callable(key, self)
# see if we can slice the rows
indexer = convert_to_index_sliceable(self, key)
if indexer is not None:
# either we have a slice or we have a string that can be converted
# to a slice for partial-string date indexing
return self._setitem_slice(indexer, value)
if isinstance(key, DataFrame) or getattr(key, "ndim", None) == 2:
self._setitem_frame(key, value)
elif isinstance(key, (Series, np.ndarray, list, Index)):
self._setitem_array(key, value)
else:
# set column
self._set_item(key, value)
def _setitem_slice(self, key: slice, value):
# NB: we can't just use self.loc[key] = value because that
# operates on labels and we need to operate positional for
# backwards-compat, xref GH#31469
self._check_setitem_copy()
self.iloc._setitem_with_indexer(key, value)
def _setitem_array(self, key, value):
# also raises Exception if object array with NA values
if com.is_bool_indexer(key):
if len(key) != len(self.index):
raise ValueError(
f"Item wrong length {len(key)} instead of {len(self.index)}!"
)
key = check_bool_indexer(self.index, key)
indexer = key.nonzero()[0]
self._check_setitem_copy()
self.iloc._setitem_with_indexer(indexer, value)
else:
if isinstance(value, DataFrame):
if len(value.columns) != len(key):
raise ValueError("Columns must be same length as key")
for k1, k2 in zip(key, value.columns):
self[k1] = value[k2]
else:
indexer = self.loc._get_listlike_indexer(
key, axis=1, raise_missing=False
)[1]
self._check_setitem_copy()
self.iloc._setitem_with_indexer((slice(None), indexer), value)
def _setitem_frame(self, key, value):
# support boolean setting with DataFrame input, e.g.
# df[df > df2] = 0
if isinstance(key, np.ndarray):
if key.shape != self.shape:
raise ValueError("Array conditional must be same shape as self")
key = self._constructor(key, **self._construct_axes_dict())
if key.values.size and not is_bool_dtype(key.values):
raise TypeError(
"Must pass DataFrame or 2-d ndarray with boolean values only"
)
self._check_inplace_setting(value)
self._check_setitem_copy()
self._where(-key, value, inplace=True)
def _iset_item(self, loc: int, value):
self._ensure_valid_index(value)
# technically _sanitize_column expects a label, not a position,
# but the behavior is the same as long as we pass broadcast=False
value = self._sanitize_column(loc, value, broadcast=False)
NDFrame._iset_item(self, loc, value)
# check if we are modifying a copy
# try to set first as we want an invalid
# value exception to occur first
if len(self):
self._check_setitem_copy()
def _set_item(self, key, value):
"""
Add series to DataFrame in specified column.
If series is a numpy-array (not a Series/TimeSeries), it must be the
same length as the DataFrames index or an error will be thrown.
Series/TimeSeries will be conformed to the DataFrames index to
ensure homogeneity.
"""
self._ensure_valid_index(value)
value = self._sanitize_column(key, value)
NDFrame._set_item(self, key, value)
# check if we are modifying a copy
# try to set first as we want an invalid
# value exception to occur first
if len(self):
self._check_setitem_copy()
def _set_value(self, index, col, value, takeable: bool = False):
"""
Put single value at passed column and index.
Parameters
----------
index : row label
col : column label
value : scalar
takeable : interpret the index/col as indexers, default False
"""
try:
if takeable is True:
series = self._ixs(col, axis=1)
series._set_value(index, value, takeable=True)
return
series = self._get_item_cache(col)
engine = self.index._engine
loc = engine.get_loc(index)
validate_numeric_casting(series.dtype, value)
series._values[loc] = value
# Note: trying to use series._set_value breaks tests in
# tests.frame.indexing.test_indexing and tests.indexing.test_partial
except (KeyError, TypeError):
# set using a non-recursive method & reset the cache
if takeable:
self.iloc[index, col] = value
else:
self.loc[index, col] = value
self._item_cache.pop(col, None)
def _ensure_valid_index(self, value):
"""
Ensure that if we don't have an index, that we can create one from the
passed value.
"""
# GH5632, make sure that we are a Series convertible
if not len(self.index) and is_list_like(value) and len(value):
try:
value = Series(value)
except (ValueError, NotImplementedError, TypeError) as err:
raise ValueError(
"Cannot set a frame with no defined index "
"and a value that cannot be converted to a Series"
) from err
self._data = self._data.reindex_axis(
value.index.copy(), axis=1, fill_value=np.nan
)
def _box_item_values(self, key, values):
items = self.columns[self.columns.get_loc(key)]
if values.ndim == 2:
return self._constructor(values.T, columns=items, index=self.index)
else:
return self._box_col_values(values, items)
def _box_col_values(self, values, items):
"""
Provide boxed values for a column.
"""
klass = self._constructor_sliced
return klass(values, index=self.index, name=items, fastpath=True)
# ----------------------------------------------------------------------
# Unsorted
def query(self, expr, inplace=False, **kwargs):
"""
Query the columns of a DataFrame with a boolean expression.
Parameters
----------
expr : str
The query string to evaluate.
You can refer to variables
in the environment by prefixing them with an '@' character like
``@a + b``.
You can refer to column names that contain spaces or operators by
surrounding them in backticks. This way you can also escape
names that start with a digit, or those that are a Python keyword.
Basically when it is not valid Python identifier. See notes down
for more details.
For example, if one of your columns is called ``a a`` and you want
to sum it with ``b``, your query should be ```a a` + b``.
.. versionadded:: 0.25.0
Backtick quoting introduced.
.. versionadded:: 1.0.0
Expanding functionality of backtick quoting for more than only spaces.
inplace : bool
Whether the query should modify the data in place or return
a modified copy.
**kwargs
See the documentation for :func:`eval` for complete details
on the keyword arguments accepted by :meth:`DataFrame.query`.
Returns
-------
DataFrame
DataFrame resulting from the provided query expression.
See Also
--------
eval : Evaluate a string describing operations on
DataFrame columns.
DataFrame.eval : Evaluate a string describing operations on
DataFrame columns.
Notes
-----
The result of the evaluation of this expression is first passed to
:attr:`DataFrame.loc` and if that fails because of a
multidimensional key (e.g., a DataFrame) then the result will be passed
to :meth:`DataFrame.__getitem__`.
This method uses the top-level :func:`eval` function to
evaluate the passed query.
The :meth:`~pandas.DataFrame.query` method uses a slightly
modified Python syntax by default. For example, the ``&`` and ``|``
(bitwise) operators have the precedence of their boolean cousins,
:keyword:`and` and :keyword:`or`. This *is* syntactically valid Python,
however the semantics are different.
You can change the semantics of the expression by passing the keyword
argument ``parser='python'``. This enforces the same semantics as
evaluation in Python space. Likewise, you can pass ``engine='python'``
to evaluate an expression using Python itself as a backend. This is not
recommended as it is inefficient compared to using ``numexpr`` as the
engine.
The :attr:`DataFrame.index` and
:attr:`DataFrame.columns` attributes of the
:class:`~pandas.DataFrame` instance are placed in the query namespace
by default, which allows you to treat both the index and columns of the
frame as a column in the frame.
The identifier ``index`` is used for the frame index; you can also
use the name of the index to identify it in a query. Please note that
Python keywords may not be used as identifiers.
For further details and examples see the ``query`` documentation in
:ref:`indexing <indexing.query>`.
*Backtick quoted variables*
Backtick quoted variables are parsed as literal Python code and
are converted internally to a Python valid identifier.
This can lead to the following problems.
During parsing a number of disallowed characters inside the backtick
quoted string are replaced by strings that are allowed as a Python identifier.
These characters include all operators in Python, the space character, the
question mark, the exclamation mark, the dollar sign, and the euro sign.
For other characters that fall outside the ASCII range (U+0001..U+007F)
and those that are not further specified in PEP 3131,
the query parser will raise an error.
This excludes whitespace different than the space character,
but also the hashtag (as it is used for comments) and the backtick
itself (backtick can also not be escaped).
In a special case, quotes that make a pair around a backtick can
confuse the parser.
For example, ```it's` > `that's``` will raise an error,
as it forms a quoted string (``'s > `that'``) with a backtick inside.
See also the Python documentation about lexical analysis
(https://docs.python.org/3/reference/lexical_analysis.html)
in combination with the source code in :mod:`pandas.core.computation.parsing`.
Examples
--------
>>> df = pd.DataFrame({'A': range(1, 6),
... 'B': range(10, 0, -2),
... 'C C': range(10, 5, -1)})
>>> df
A B C C
0 1 10 10
1 2 8 9
2 3 6 8
3 4 4 7
4 5 2 6
>>> df.query('A > B')
A B C C
4 5 2 6
The previous expression is equivalent to
>>> df[df.A > df.B]
A B C C
4 5 2 6
For columns with spaces in their name, you can use backtick quoting.
>>> df.query('B == `C C`')
A B C C
0 1 10 10
The previous expression is equivalent to
>>> df[df.B == df['C C']]
A B C C
0 1 10 10
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not isinstance(expr, str):
msg = f"expr must be a string to be evaluated, {type(expr)} given"
raise ValueError(msg)
kwargs["level"] = kwargs.pop("level", 0) + 1
kwargs["target"] = None
res = self.eval(expr, **kwargs)
try:
new_data = self.loc[res]
except ValueError:
# when res is multi-dimensional loc raises, but this is sometimes a
# valid query
new_data = self[res]
if inplace:
self._update_inplace(new_data)
else:
return new_data
def eval(self, expr, inplace=False, **kwargs):
"""
Evaluate a string describing operations on DataFrame columns.
Operates on columns only, not specific rows or elements. This allows
`eval` to run arbitrary code, which can make you vulnerable to code
injection if you pass user input to this function.
Parameters
----------
expr : str
The expression string to evaluate.
inplace : bool, default False
If the expression contains an assignment, whether to perform the
operation inplace and mutate the existing DataFrame. Otherwise,
a new DataFrame is returned.
**kwargs
See the documentation for :func:`eval` for complete details
on the keyword arguments accepted by
:meth:`~pandas.DataFrame.query`.
Returns
-------
ndarray, scalar, or pandas object
The result of the evaluation.
See Also
--------
DataFrame.query : Evaluates a boolean expression to query the columns
of a frame.
DataFrame.assign : Can evaluate an expression or function to create new
values for a column.
eval : Evaluate a Python expression as a string using various
backends.
Notes
-----
For more details see the API documentation for :func:`~eval`.
For detailed examples see :ref:`enhancing performance with eval
<enhancingperf.eval>`.
Examples
--------
>>> df = pd.DataFrame({'A': range(1, 6), 'B': range(10, 0, -2)})
>>> df
A B
0 1 10
1 2 8
2 3 6
3 4 4
4 5 2
>>> df.eval('A + B')
0 11
1 10
2 9
3 8
4 7
dtype: int64
Assignment is allowed though by default the original DataFrame is not
modified.
>>> df.eval('C = A + B')
A B C
0 1 10 11
1 2 8 10
2 3 6 9
3 4 4 8
4 5 2 7
>>> df
A B
0 1 10
1 2 8
2 3 6
3 4 4
4 5 2
Use ``inplace=True`` to modify the original DataFrame.
>>> df.eval('C = A + B', inplace=True)
>>> df
A B C
0 1 10 11
1 2 8 10
2 3 6 9
3 4 4 8
4 5 2 7
Multiple columns can be assigned to using multi-line expressions:
>>> df.eval(
... '''
... C = A + B
... D = A - B
... '''
... )
A B C D
0 1 10 11 -9
1 2 8 10 -6
2 3 6 9 -3
3 4 4 8 0
4 5 2 7 3
"""
from pandas.core.computation.eval import eval as _eval
inplace = validate_bool_kwarg(inplace, "inplace")
resolvers = kwargs.pop("resolvers", None)
kwargs["level"] = kwargs.pop("level", 0) + 1
if resolvers is None:
index_resolvers = self._get_index_resolvers()
column_resolvers = self._get_cleaned_column_resolvers()
resolvers = column_resolvers, index_resolvers
if "target" not in kwargs:
kwargs["target"] = self
kwargs["resolvers"] = kwargs.get("resolvers", ()) + tuple(resolvers)
return _eval(expr, inplace=inplace, **kwargs)
def select_dtypes(self, include=None, exclude=None) -> "DataFrame":
"""
Return a subset of the DataFrame's columns based on the column dtypes.
Parameters
----------
include, exclude : scalar or list-like
A selection of dtypes or strings to be included/excluded. At least
one of these parameters must be supplied.
Returns
-------
DataFrame
The subset of the frame including the dtypes in ``include`` and
excluding the dtypes in ``exclude``.
Raises
------
ValueError
* If both of ``include`` and ``exclude`` are empty
* If ``include`` and ``exclude`` have overlapping elements
* If any kind of string dtype is passed in.
Notes
-----
* To select all *numeric* types, use ``np.number`` or ``'number'``
* To select strings you must use the ``object`` dtype, but note that
this will return *all* object dtype columns
* See the `numpy dtype hierarchy
<https://docs.scipy.org/doc/numpy/reference/arrays.scalars.html>`__
* To select datetimes, use ``np.datetime64``, ``'datetime'`` or
``'datetime64'``
* To select timedeltas, use ``np.timedelta64``, ``'timedelta'`` or
``'timedelta64'``
* To select Pandas categorical dtypes, use ``'category'``
* To select Pandas datetimetz dtypes, use ``'datetimetz'`` (new in
0.20.0) or ``'datetime64[ns, tz]'``
Examples
--------
>>> df = pd.DataFrame({'a': [1, 2] * 3,
... 'b': [True, False] * 3,
... 'c': [1.0, 2.0] * 3})
>>> df
a b c
0 1 True 1.0
1 2 False 2.0
2 1 True 1.0
3 2 False 2.0
4 1 True 1.0
5 2 False 2.0
>>> df.select_dtypes(include='bool')
b
0 True
1 False
2 True
3 False
4 True
5 False
>>> df.select_dtypes(include=['float64'])
c
0 1.0
1 2.0
2 1.0
3 2.0
4 1.0
5 2.0
>>> df.select_dtypes(exclude=['int'])
b c
0 True 1.0
1 False 2.0
2 True 1.0
3 False 2.0
4 True 1.0
5 False 2.0
"""
if not is_list_like(include):
include = (include,) if include is not None else ()
if not is_list_like(exclude):
exclude = (exclude,) if exclude is not None else ()
selection = (frozenset(include), frozenset(exclude))
if not any(selection):
raise ValueError("at least one of include or exclude must be nonempty")
# convert the myriad valid dtypes object to a single representation
include = frozenset(infer_dtype_from_object(x) for x in include)
exclude = frozenset(infer_dtype_from_object(x) for x in exclude)
for dtypes in (include, exclude):
invalidate_string_dtypes(dtypes)
# can't both include AND exclude!
if not include.isdisjoint(exclude):
raise ValueError(f"include and exclude overlap on {(include & exclude)}")
# We raise when both include and exclude are empty
# Hence, we can just shrink the columns we want to keep
keep_these = np.full(self.shape[1], True)
def extract_unique_dtypes_from_dtypes_set(
dtypes_set: FrozenSet[Dtype], unique_dtypes: np.ndarray
) -> List[Dtype]:
extracted_dtypes = [
unique_dtype
for unique_dtype in unique_dtypes
if issubclass(unique_dtype.type, tuple(dtypes_set)) # type: ignore
]
return extracted_dtypes
unique_dtypes = self.dtypes.unique()
if include:
included_dtypes = extract_unique_dtypes_from_dtypes_set(
include, unique_dtypes
)
keep_these &= self.dtypes.isin(included_dtypes)
if exclude:
excluded_dtypes = extract_unique_dtypes_from_dtypes_set(
exclude, unique_dtypes
)
keep_these &= ~self.dtypes.isin(excluded_dtypes)
return self.iloc[:, keep_these.values]
def insert(self, loc, column, value, allow_duplicates=False) -> None:
"""
Insert column into DataFrame at specified location.
Raises a ValueError if `column` is already contained in the DataFrame,
unless `allow_duplicates` is set to True.
Parameters
----------
loc : int
Insertion index. Must verify 0 <= loc <= len(columns).
column : str, number, or hashable object
Label of the inserted column.
value : int, Series, or array-like
allow_duplicates : bool, optional
"""
self._ensure_valid_index(value)
value = self._sanitize_column(column, value, broadcast=False)
self._data.insert(loc, column, value, allow_duplicates=allow_duplicates)
def assign(self, **kwargs) -> "DataFrame":
r"""
Assign new columns to a DataFrame.
Returns a new object with all original columns in addition to new ones.
Existing columns that are re-assigned will be overwritten.
Parameters
----------
**kwargs : dict of {str: callable or Series}
The column names are keywords. If the values are
callable, they are computed on the DataFrame and
assigned to the new columns. The callable must not
change input DataFrame (though pandas doesn't check it).
If the values are not callable, (e.g. a Series, scalar, or array),
they are simply assigned.
Returns
-------
DataFrame
A new DataFrame with the new columns in addition to
all the existing columns.
Notes
-----
Assigning multiple columns within the same ``assign`` is possible.
Later items in '\*\*kwargs' may refer to newly created or modified
columns in 'df'; items are computed and assigned into 'df' in order.
.. versionchanged:: 0.23.0
Keyword argument order is maintained.
Examples
--------
>>> df = pd.DataFrame({'temp_c': [17.0, 25.0]},
... index=['Portland', 'Berkeley'])
>>> df
temp_c
Portland 17.0
Berkeley 25.0
Where the value is a callable, evaluated on `df`:
>>> df.assign(temp_f=lambda x: x.temp_c * 9 / 5 + 32)
temp_c temp_f
Portland 17.0 62.6
Berkeley 25.0 77.0
Alternatively, the same behavior can be achieved by directly
referencing an existing Series or sequence:
>>> df.assign(temp_f=df['temp_c'] * 9 / 5 + 32)
temp_c temp_f
Portland 17.0 62.6
Berkeley 25.0 77.0
You can create multiple columns within the same assign where one
of the columns depends on another one defined within the same assign:
>>> df.assign(temp_f=lambda x: x['temp_c'] * 9 / 5 + 32,
... temp_k=lambda x: (x['temp_f'] + 459.67) * 5 / 9)
temp_c temp_f temp_k
Portland 17.0 62.6 290.15
Berkeley 25.0 77.0 298.15
"""
data = self.copy()
for k, v in kwargs.items():
data[k] = com.apply_if_callable(v, data)
return data
def _sanitize_column(self, key, value, broadcast=True):
"""
Ensures new columns (which go into the BlockManager as new blocks) are
always copied and converted into an array.
Parameters
----------
key : object
value : scalar, Series, or array-like
broadcast : bool, default True
If ``key`` matches multiple duplicate column names in the
DataFrame, this parameter indicates whether ``value`` should be
tiled so that the returned array contains a (duplicated) column for
each occurrence of the key. If False, ``value`` will not be tiled.
Returns
-------
numpy.ndarray
"""
def reindexer(value):
# reindex if necessary
if value.index.equals(self.index) or not len(self.index):
value = value._values.copy()
else:
# GH 4107
try:
value = value.reindex(self.index)._values
except ValueError as err:
# raised in MultiIndex.from_tuples, see test_insert_error_msmgs
if not value.index.is_unique:
# duplicate axis
raise err
# other
raise TypeError(
"incompatible index of inserted column with frame index"
) from err
return value
if isinstance(value, Series):
value = reindexer(value)
elif isinstance(value, DataFrame):
# align right-hand-side columns if self.columns
# is multi-index and self[key] is a sub-frame
if isinstance(self.columns, ABCMultiIndex) and key in self.columns:
loc = self.columns.get_loc(key)
if isinstance(loc, (slice, Series, np.ndarray, Index)):
cols = maybe_droplevels(self.columns[loc], key)
if len(cols) and not cols.equals(value.columns):
value = value.reindex(cols, axis=1)
# now align rows
value = reindexer(value).T
elif isinstance(value, ExtensionArray):
# Explicitly copy here, instead of in sanitize_index,
# as sanitize_index won't copy an EA, even with copy=True
value = value.copy()
value = sanitize_index(value, self.index)
elif isinstance(value, Index) or is_sequence(value):
# turn me into an ndarray
value = sanitize_index(value, self.index)
if not isinstance(value, (np.ndarray, Index)):
if isinstance(value, list) and len(value) > 0:
value = maybe_convert_platform(value)
else:
value = com.asarray_tuplesafe(value)
elif value.ndim == 2:
value = value.copy().T
elif isinstance(value, Index):
value = value.copy(deep=True)
else:
value = value.copy()
# possibly infer to datetimelike
if is_object_dtype(value.dtype):
value = maybe_infer_to_datetimelike(value)
else:
# cast ignores pandas dtypes. so save the dtype first
infer_dtype, _ = infer_dtype_from_scalar(value, pandas_dtype=True)
# upcast
value = cast_scalar_to_array(len(self.index), value)
value = maybe_cast_to_datetime(value, infer_dtype)
# return internal types directly
if is_extension_array_dtype(value):
return value
# broadcast across multiple columns if necessary
if broadcast and key in self.columns and value.ndim == 1:
if not self.columns.is_unique or isinstance(self.columns, ABCMultiIndex):
existing_piece = self[key]
if isinstance(existing_piece, DataFrame):
value = np.tile(value, (len(existing_piece.columns), 1))
return np.atleast_2d(np.asarray(value))
@property
def _series(self):
return {
item: Series(self._data.iget(idx), index=self.index, name=item)
for idx, item in enumerate(self.columns)
}
def lookup(self, row_labels, col_labels) -> np.ndarray:
"""
Label-based "fancy indexing" function for DataFrame.
Given equal-length arrays of row and column labels, return an
array of the values corresponding to each (row, col) pair.
Parameters
----------
row_labels : sequence
The row labels to use for lookup.
col_labels : sequence
The column labels to use for lookup.
Returns
-------
numpy.ndarray
The found values.
"""
n = len(row_labels)
if n != len(col_labels):
raise ValueError("Row labels must have same size as column labels")
thresh = 1000
if not self._is_mixed_type or n > thresh:
values = self.values
ridx = self.index.get_indexer(row_labels)
cidx = self.columns.get_indexer(col_labels)
if (ridx == -1).any():
raise KeyError("One or more row labels was not found")
if (cidx == -1).any():
raise KeyError("One or more column labels was not found")
flat_index = ridx * len(self.columns) + cidx
result = values.flat[flat_index]
else:
result = np.empty(n, dtype="O")
for i, (r, c) in enumerate(zip(row_labels, col_labels)):
result[i] = self._get_value(r, c)
if is_object_dtype(result):
result = lib.maybe_convert_objects(result)
return result
# ----------------------------------------------------------------------
# Reindexing and alignment
def _reindex_axes(self, axes, level, limit, tolerance, method, fill_value, copy):
frame = self
columns = axes["columns"]
if columns is not None:
frame = frame._reindex_columns(
columns, method, copy, level, fill_value, limit, tolerance
)
index = axes["index"]
if index is not None:
frame = frame._reindex_index(
index, method, copy, level, fill_value, limit, tolerance
)
return frame
def _reindex_index(
self,
new_index,
method,
copy,
level,
fill_value=np.nan,
limit=None,
tolerance=None,
):
new_index, indexer = self.index.reindex(
new_index, method=method, level=level, limit=limit, tolerance=tolerance
)
return self._reindex_with_indexers(
{0: [new_index, indexer]},
copy=copy,
fill_value=fill_value,
allow_dups=False,
)
def _reindex_columns(
self,
new_columns,
method,
copy,
level,
fill_value=None,
limit=None,
tolerance=None,
):
new_columns, indexer = self.columns.reindex(
new_columns, method=method, level=level, limit=limit, tolerance=tolerance
)
return self._reindex_with_indexers(
{1: [new_columns, indexer]},
copy=copy,
fill_value=fill_value,
allow_dups=False,
)
def _reindex_multi(self, axes, copy, fill_value) -> "DataFrame":
"""
We are guaranteed non-Nones in the axes.
"""
new_index, row_indexer = self.index.reindex(axes["index"])
new_columns, col_indexer = self.columns.reindex(axes["columns"])
if row_indexer is not None and col_indexer is not None:
indexer = row_indexer, col_indexer
new_values = algorithms.take_2d_multi(
self.values, indexer, fill_value=fill_value
)
return self._constructor(new_values, index=new_index, columns=new_columns)
else:
return self._reindex_with_indexers(
{0: [new_index, row_indexer], 1: [new_columns, col_indexer]},
copy=copy,
fill_value=fill_value,
)
@Appender(_shared_docs["align"] % _shared_doc_kwargs)
def align(
self,
other,
join="outer",
axis=None,
level=None,
copy=True,
fill_value=None,
method=None,
limit=None,
fill_axis=0,
broadcast_axis=None,
) -> "DataFrame":
return super().align(
other,
join=join,
axis=axis,
level=level,
copy=copy,
fill_value=fill_value,
method=method,
limit=limit,
fill_axis=fill_axis,
broadcast_axis=broadcast_axis,
)
@Appender(
"""
Examples
--------
>>> df = pd.DataFrame({"A": [1, 2, 3], "B": [4, 5, 6]})
Change the row labels.
>>> df.set_axis(['a', 'b', 'c'], axis='index')
A B
a 1 4
b 2 5
c 3 6
Change the column labels.
>>> df.set_axis(['I', 'II'], axis='columns')
I II
0 1 4
1 2 5
2 3 6
Now, update the labels inplace.
>>> df.set_axis(['i', 'ii'], axis='columns', inplace=True)
>>> df
i ii
0 1 4
1 2 5
2 3 6
"""
)
@Substitution(
**_shared_doc_kwargs,
extended_summary_sub=" column or",
axis_description_sub=", and 1 identifies the columns",
see_also_sub=" or columns",
)
@Appender(NDFrame.set_axis.__doc__)
def set_axis(self, labels, axis: Axis = 0, inplace: bool = False):
return super().set_axis(labels, axis=axis, inplace=inplace)
@Substitution(**_shared_doc_kwargs)
@Appender(NDFrame.reindex.__doc__)
@rewrite_axis_style_signature(
"labels",
[
("method", None),
("copy", True),
("level", None),
("fill_value", np.nan),
("limit", None),
("tolerance", None),
],
)
def reindex(self, *args, **kwargs) -> "DataFrame":
axes = validate_axis_style_args(self, args, kwargs, "labels", "reindex")
kwargs.update(axes)
# Pop these, since the values are in `kwargs` under different names
kwargs.pop("axis", None)
kwargs.pop("labels", None)
return super().reindex(**kwargs)
def drop(
self,
labels=None,
axis=0,
index=None,
columns=None,
level=None,
inplace=False,
errors="raise",
):
"""
Drop specified labels from rows or columns.
Remove rows or columns by specifying label names and corresponding
axis, or by specifying directly index or column names. When using a
multi-index, labels on different levels can be removed by specifying
the level.
Parameters
----------
labels : single label or list-like
Index or column labels to drop.
axis : {0 or 'index', 1 or 'columns'}, default 0
Whether to drop labels from the index (0 or 'index') or
columns (1 or 'columns').
index : single label or list-like
Alternative to specifying axis (``labels, axis=0``
is equivalent to ``index=labels``).
.. versionadded:: 0.21.0
columns : single label or list-like
Alternative to specifying axis (``labels, axis=1``
is equivalent to ``columns=labels``).
.. versionadded:: 0.21.0
level : int or level name, optional
For MultiIndex, level from which the labels will be removed.
inplace : bool, default False
If True, do operation inplace and return None.
errors : {'ignore', 'raise'}, default 'raise'
If 'ignore', suppress error and only existing labels are
dropped.
Returns
-------
DataFrame
DataFrame without the removed index or column labels.
Raises
------
KeyError
If any of the labels is not found in the selected axis.
See Also
--------
DataFrame.loc : Label-location based indexer for selection by label.
DataFrame.dropna : Return DataFrame with labels on given axis omitted
where (all or any) data are missing.
DataFrame.drop_duplicates : Return DataFrame with duplicate rows
removed, optionally only considering certain columns.
Series.drop : Return Series with specified index labels removed.
Examples
--------
>>> df = pd.DataFrame(np.arange(12).reshape(3, 4),
... columns=['A', 'B', 'C', 'D'])
>>> df
A B C D
0 0 1 2 3
1 4 5 6 7
2 8 9 10 11
Drop columns
>>> df.drop(['B', 'C'], axis=1)
A D
0 0 3
1 4 7
2 8 11
>>> df.drop(columns=['B', 'C'])
A D
0 0 3
1 4 7
2 8 11
Drop a row by index
>>> df.drop([0, 1])
A B C D
2 8 9 10 11
Drop columns and/or rows of MultiIndex DataFrame
>>> midx = pd.MultiIndex(levels=[['lama', 'cow', 'falcon'],
... ['speed', 'weight', 'length']],
... codes=[[0, 0, 0, 1, 1, 1, 2, 2, 2],
... [0, 1, 2, 0, 1, 2, 0, 1, 2]])
>>> df = pd.DataFrame(index=midx, columns=['big', 'small'],
... data=[[45, 30], [200, 100], [1.5, 1], [30, 20],
... [250, 150], [1.5, 0.8], [320, 250],
... [1, 0.8], [0.3, 0.2]])
>>> df
big small
lama speed 45.0 30.0
weight 200.0 100.0
length 1.5 1.0
cow speed 30.0 20.0
weight 250.0 150.0
length 1.5 0.8
falcon speed 320.0 250.0
weight 1.0 0.8
length 0.3 0.2
>>> df.drop(index='cow', columns='small')
big
lama speed 45.0
weight 200.0
length 1.5
falcon speed 320.0
weight 1.0
length 0.3
>>> df.drop(index='length', level=1)
big small
lama speed 45.0 30.0
weight 200.0 100.0
cow speed 30.0 20.0
weight 250.0 150.0
falcon speed 320.0 250.0
weight 1.0 0.8
"""
return super().drop(
labels=labels,
axis=axis,
index=index,
columns=columns,
level=level,
inplace=inplace,
errors=errors,
)
@rewrite_axis_style_signature(
"mapper",
[("copy", True), ("inplace", False), ("level", None), ("errors", "ignore")],
)
def rename(
self,
mapper: Optional[Renamer] = None,
*,
index: Optional[Renamer] = None,
columns: Optional[Renamer] = None,
axis: Optional[Axis] = None,
copy: bool = True,
inplace: bool = False,
level: Optional[Level] = None,
errors: str = "ignore",
) -> Optional["DataFrame"]:
"""
Alter axes labels.
Function / dict values must be unique (1-to-1). Labels not contained in
a dict / Series will be left as-is. Extra labels listed don't throw an
error.
See the :ref:`user guide <basics.rename>` for more.
Parameters
----------
mapper : dict-like or function
Dict-like or functions transformations to apply to
that axis' values. Use either ``mapper`` and ``axis`` to
specify the axis to target with ``mapper``, or ``index`` and
``columns``.
index : dict-like or function
Alternative to specifying axis (``mapper, axis=0``
is equivalent to ``index=mapper``).
columns : dict-like or function
Alternative to specifying axis (``mapper, axis=1``
is equivalent to ``columns=mapper``).
axis : int or str
Axis to target with ``mapper``. Can be either the axis name
('index', 'columns') or number (0, 1). The default is 'index'.
copy : bool, default True
Also copy underlying data.
inplace : bool, default False
Whether to return a new DataFrame. If True then value of copy is
ignored.
level : int or level name, default None
In case of a MultiIndex, only rename labels in the specified
level.
errors : {'ignore', 'raise'}, default 'ignore'
If 'raise', raise a `KeyError` when a dict-like `mapper`, `index`,
or `columns` contains labels that are not present in the Index
being transformed.
If 'ignore', existing keys will be renamed and extra keys will be
ignored.
Returns
-------
DataFrame
DataFrame with the renamed axis labels.
Raises
------
KeyError
If any of the labels is not found in the selected axis and
"errors='raise'".
See Also
--------
DataFrame.rename_axis : Set the name of the axis.
Examples
--------
``DataFrame.rename`` supports two calling conventions
* ``(index=index_mapper, columns=columns_mapper, ...)``
* ``(mapper, axis={'index', 'columns'}, ...)``
We *highly* recommend using keyword arguments to clarify your
intent.
Rename columns using a mapping:
>>> df = pd.DataFrame({"A": [1, 2, 3], "B": [4, 5, 6]})
>>> df.rename(columns={"A": "a", "B": "c"})
a c
0 1 4
1 2 5
2 3 6
Rename index using a mapping:
>>> df.rename(index={0: "x", 1: "y", 2: "z"})
A B
x 1 4
y 2 5
z 3 6
Cast index labels to a different type:
>>> df.index
RangeIndex(start=0, stop=3, step=1)
>>> df.rename(index=str).index
Index(['0', '1', '2'], dtype='object')
>>> df.rename(columns={"A": "a", "B": "b", "C": "c"}, errors="raise")
Traceback (most recent call last):
KeyError: ['C'] not found in axis
Using axis-style parameters
>>> df.rename(str.lower, axis='columns')
a b
0 1 4
1 2 5
2 3 6
>>> df.rename({1: 2, 2: 4}, axis='index')
A B
0 1 4
2 2 5
4 3 6
"""
return super().rename(
mapper=mapper,
index=index,
columns=columns,
axis=axis,
copy=copy,
inplace=inplace,
level=level,
errors=errors,
)
@doc(NDFrame.fillna, **_shared_doc_kwargs)
def fillna(
self,
value=None,
method=None,
axis=None,
inplace=False,
limit=None,
downcast=None,
) -> Optional["DataFrame"]:
return super().fillna(
value=value,
method=method,
axis=axis,
inplace=inplace,
limit=limit,
downcast=downcast,
)
@Appender(_shared_docs["replace"] % _shared_doc_kwargs)
def replace(
self,
to_replace=None,
value=None,
inplace=False,
limit=None,
regex=False,
method="pad",
):
return super().replace(
to_replace=to_replace,
value=value,
inplace=inplace,
limit=limit,
regex=regex,
method=method,
)
@Appender(_shared_docs["shift"] % _shared_doc_kwargs)
def shift(self, periods=1, freq=None, axis=0, fill_value=None) -> "DataFrame":
return super().shift(
periods=periods, freq=freq, axis=axis, fill_value=fill_value
)
def set_index(
self, keys, drop=True, append=False, inplace=False, verify_integrity=False
):
"""
Set the DataFrame index using existing columns.
Set the DataFrame index (row labels) using one or more existing
columns or arrays (of the correct length). The index can replace the
existing index or expand on it.
Parameters
----------
keys : label or array-like or list of labels/arrays
This parameter can be either a single column key, a single array of
the same length as the calling DataFrame, or a list containing an
arbitrary combination of column keys and arrays. Here, "array"
encompasses :class:`Series`, :class:`Index`, ``np.ndarray``, and
instances of :class:`~collections.abc.Iterator`.
drop : bool, default True
Delete columns to be used as the new index.
append : bool, default False
Whether to append columns to existing index.
inplace : bool, default False
Modify the DataFrame in place (do not create a new object).
verify_integrity : bool, default False
Check the new index for duplicates. Otherwise defer the check until
necessary. Setting to False will improve the performance of this
method.
Returns
-------
DataFrame
Changed row labels.
See Also
--------
DataFrame.reset_index : Opposite of set_index.
DataFrame.reindex : Change to new indices or expand indices.
DataFrame.reindex_like : Change to same indices as other DataFrame.
Examples
--------
>>> df = pd.DataFrame({'month': [1, 4, 7, 10],
... 'year': [2012, 2014, 2013, 2014],
... 'sale': [55, 40, 84, 31]})
>>> df
month year sale
0 1 2012 55
1 4 2014 40
2 7 2013 84
3 10 2014 31
Set the index to become the 'month' column:
>>> df.set_index('month')
year sale
month
1 2012 55
4 2014 40
7 2013 84
10 2014 31
Create a MultiIndex using columns 'year' and 'month':
>>> df.set_index(['year', 'month'])
sale
year month
2012 1 55
2014 4 40
2013 7 84
2014 10 31
Create a MultiIndex using an Index and a column:
>>> df.set_index([pd.Index([1, 2, 3, 4]), 'year'])
month sale
year
1 2012 1 55
2 2014 4 40
3 2013 7 84
4 2014 10 31
Create a MultiIndex using two Series:
>>> s = pd.Series([1, 2, 3, 4])
>>> df.set_index([s, s**2])
month year sale
1 1 1 2012 55
2 4 4 2014 40
3 9 7 2013 84
4 16 10 2014 31
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not isinstance(keys, list):
keys = [keys]
err_msg = (
'The parameter "keys" may be a column key, one-dimensional '
"array, or a list containing only valid column keys and "
"one-dimensional arrays."
)
missing: List[Label] = []
for col in keys:
if isinstance(
col, (ABCIndexClass, ABCSeries, np.ndarray, list, abc.Iterator)
):
# arrays are fine as long as they are one-dimensional
# iterators get converted to list below
if getattr(col, "ndim", 1) != 1:
raise ValueError(err_msg)
else:
# everything else gets tried as a key; see GH 24969
try:
found = col in self.columns
except TypeError as err:
raise TypeError(
f"{err_msg}. Received column of type {type(col)}"
) from err
else:
if not found:
missing.append(col)
if missing:
raise KeyError(f"None of {missing} are in the columns")
if inplace:
frame = self
else:
frame = self.copy()
arrays = []
names = []
if append:
names = list(self.index.names)
if isinstance(self.index, ABCMultiIndex):
for i in range(self.index.nlevels):
arrays.append(self.index._get_level_values(i))
else:
arrays.append(self.index)
to_remove: List[Label] = []
for col in keys:
if isinstance(col, ABCMultiIndex):
for n in range(col.nlevels):
arrays.append(col._get_level_values(n))
names.extend(col.names)
elif isinstance(col, (ABCIndexClass, ABCSeries)):
# if Index then not MultiIndex (treated above)
arrays.append(col)
names.append(col.name)
elif isinstance(col, (list, np.ndarray)):
arrays.append(col)
names.append(None)
elif isinstance(col, abc.Iterator):
arrays.append(list(col))
names.append(None)
# from here, col can only be a column label
else:
arrays.append(frame[col]._values)
names.append(col)
if drop:
to_remove.append(col)
if len(arrays[-1]) != len(self):
# check newest element against length of calling frame, since
# ensure_index_from_sequences would not raise for append=False.
raise ValueError(
f"Length mismatch: Expected {len(self)} rows, "
f"received array of length {len(arrays[-1])}"
)
index = ensure_index_from_sequences(arrays, names)
if verify_integrity and not index.is_unique:
duplicates = index[index.duplicated()].unique()
raise ValueError(f"Index has duplicate keys: {duplicates}")
# use set to handle duplicate column names gracefully in case of drop
for c in set(to_remove):
del frame[c]
# clear up memory usage
index._cleanup()
frame.index = index
if not inplace:
return frame
def reset_index(
self,
level: Optional[Union[Hashable, Sequence[Hashable]]] = None,
drop: bool = False,
inplace: bool = False,
col_level: Hashable = 0,
col_fill: Label = "",
) -> Optional["DataFrame"]:
"""
Reset the index, or a level of it.
Reset the index of the DataFrame, and use the default one instead.
If the DataFrame has a MultiIndex, this method can remove one or more
levels.
Parameters
----------
level : int, str, tuple, or list, default None
Only remove the given levels from the index. Removes all levels by
default.
drop : bool, default False
Do not try to insert index into dataframe columns. This resets
the index to the default integer index.
inplace : bool, default False
Modify the DataFrame in place (do not create a new object).
col_level : int or str, default 0
If the columns have multiple levels, determines which level the
labels are inserted into. By default it is inserted into the first
level.
col_fill : object, default ''
If the columns have multiple levels, determines how the other
levels are named. If None then the index name is repeated.
Returns
-------
DataFrame or None
DataFrame with the new index or None if ``inplace=True``.
See Also
--------
DataFrame.set_index : Opposite of reset_index.
DataFrame.reindex : Change to new indices or expand indices.
DataFrame.reindex_like : Change to same indices as other DataFrame.
Examples
--------
>>> df = pd.DataFrame([('bird', 389.0),
... ('bird', 24.0),
... ('mammal', 80.5),
... ('mammal', np.nan)],
... index=['falcon', 'parrot', 'lion', 'monkey'],
... columns=('class', 'max_speed'))
>>> df
class max_speed
falcon bird 389.0
parrot bird 24.0
lion mammal 80.5
monkey mammal NaN
When we reset the index, the old index is added as a column, and a
new sequential index is used:
>>> df.reset_index()
index class max_speed
0 falcon bird 389.0
1 parrot bird 24.0
2 lion mammal 80.5
3 monkey mammal NaN
We can use the `drop` parameter to avoid the old index being added as
a column:
>>> df.reset_index(drop=True)
class max_speed
0 bird 389.0
1 bird 24.0
2 mammal 80.5
3 mammal NaN
You can also use `reset_index` with `MultiIndex`.
>>> index = pd.MultiIndex.from_tuples([('bird', 'falcon'),
... ('bird', 'parrot'),
... ('mammal', 'lion'),
... ('mammal', 'monkey')],
... names=['class', 'name'])
>>> columns = pd.MultiIndex.from_tuples([('speed', 'max'),
... ('species', 'type')])
>>> df = pd.DataFrame([(389.0, 'fly'),
... ( 24.0, 'fly'),
... ( 80.5, 'run'),
... (np.nan, 'jump')],
... index=index,
... columns=columns)
>>> df
speed species
max type
class name
bird falcon 389.0 fly
parrot 24.0 fly
mammal lion 80.5 run
monkey NaN jump
If the index has multiple levels, we can reset a subset of them:
>>> df.reset_index(level='class')
class speed species
max type
name
falcon bird 389.0 fly
parrot bird 24.0 fly
lion mammal 80.5 run
monkey mammal NaN jump
If we are not dropping the index, by default, it is placed in the top
level. We can place it in another level:
>>> df.reset_index(level='class', col_level=1)
speed species
class max type
name
falcon bird 389.0 fly
parrot bird 24.0 fly
lion mammal 80.5 run
monkey mammal NaN jump
When the index is inserted under another level, we can specify under
which one with the parameter `col_fill`:
>>> df.reset_index(level='class', col_level=1, col_fill='species')
species speed species
class max type
name
falcon bird 389.0 fly
parrot bird 24.0 fly
lion mammal 80.5 run
monkey mammal NaN jump
If we specify a nonexistent level for `col_fill`, it is created:
>>> df.reset_index(level='class', col_level=1, col_fill='genus')
genus speed species
class max type
name
falcon bird 389.0 fly
parrot bird 24.0 fly
lion mammal 80.5 run
monkey mammal NaN jump
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if inplace:
new_obj = self
else:
new_obj = self.copy()
def _maybe_casted_values(index, labels=None):
values = index._values
if not isinstance(index, (PeriodIndex, DatetimeIndex)):
if values.dtype == np.object_:
values = lib.maybe_convert_objects(values)
# if we have the labels, extract the values with a mask
if labels is not None:
mask = labels == -1
# we can have situations where the whole mask is -1,
# meaning there is nothing found in labels, so make all nan's
if mask.all():
values = np.empty(len(mask))
values.fill(np.nan)
else:
values = values.take(labels)
# TODO(https://github.com/pandas-dev/pandas/issues/24206)
# Push this into maybe_upcast_putmask?
# We can't pass EAs there right now. Looks a bit
# complicated.
# So we unbox the ndarray_values, op, re-box.
values_type = type(values)
values_dtype = values.dtype
if issubclass(values_type, DatetimeLikeArray):
values = values._data
if mask.any():
values, _ = maybe_upcast_putmask(values, mask, np.nan)
if issubclass(values_type, DatetimeLikeArray):
values = values_type(values, dtype=values_dtype)
return values
new_index = ibase.default_index(len(new_obj))
if level is not None:
if not isinstance(level, (tuple, list)):
level = [level]
level = [self.index._get_level_number(lev) for lev in level]
if len(level) < self.index.nlevels:
new_index = self.index.droplevel(level)
if not drop:
to_insert: Iterable[Tuple[Any, Optional[Any]]]
if isinstance(self.index, ABCMultiIndex):
names = [
(n if n is not None else f"level_{i}")
for i, n in enumerate(self.index.names)
]
to_insert = zip(self.index.levels, self.index.codes)
else:
default = "index" if "index" not in self else "level_0"
names = [default] if self.index.name is None else [self.index.name]
to_insert = ((self.index, None),)
multi_col = isinstance(self.columns, ABCMultiIndex)
for i, (lev, lab) in reversed(list(enumerate(to_insert))):
if not (level is None or i in level):
continue
name = names[i]
if multi_col:
col_name = list(name) if isinstance(name, tuple) else [name]
if col_fill is None:
if len(col_name) not in (1, self.columns.nlevels):
raise ValueError(
"col_fill=None is incompatible "
f"with incomplete column name {name}"
)
col_fill = col_name[0]
lev_num = self.columns._get_level_number(col_level)
name_lst = [col_fill] * lev_num + col_name
missing = self.columns.nlevels - len(name_lst)
name_lst += [col_fill] * missing
name = tuple(name_lst)
# to ndarray and maybe infer different dtype
level_values = _maybe_casted_values(lev, lab)
new_obj.insert(0, name, level_values)
new_obj.index = new_index
if not inplace:
return new_obj
return None
# ----------------------------------------------------------------------
# Reindex-based selection methods
@Appender(_shared_docs["isna"] % _shared_doc_kwargs)
def isna(self) -> "DataFrame":
return super().isna()
@Appender(_shared_docs["isna"] % _shared_doc_kwargs)
def isnull(self) -> "DataFrame":
return super().isnull()
@Appender(_shared_docs["notna"] % _shared_doc_kwargs)
def notna(self) -> "DataFrame":
return super().notna()
@Appender(_shared_docs["notna"] % _shared_doc_kwargs)
def notnull(self) -> "DataFrame":
return super().notnull()
def dropna(self, axis=0, how="any", thresh=None, subset=None, inplace=False):
"""
Remove missing values.
See the :ref:`User Guide <missing_data>` for more on which values are
considered missing, and how to work with missing data.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
Determine if rows or columns which contain missing values are
removed.
* 0, or 'index' : Drop rows which contain missing values.
* 1, or 'columns' : Drop columns which contain missing value.
.. versionchanged:: 1.0.0
Pass tuple or list to drop on multiple axes.
Only a single axis is allowed.
how : {'any', 'all'}, default 'any'
Determine if row or column is removed from DataFrame, when we have
at least one NA or all NA.
* 'any' : If any NA values are present, drop that row or column.
* 'all' : If all values are NA, drop that row or column.
thresh : int, optional
Require that many non-NA values.
subset : array-like, optional
Labels along other axis to consider, e.g. if you are dropping rows
these would be a list of columns to include.
inplace : bool, default False
If True, do operation inplace and return None.
Returns
-------
DataFrame
DataFrame with NA entries dropped from it.
See Also
--------
DataFrame.isna: Indicate missing values.
DataFrame.notna : Indicate existing (non-missing) values.
DataFrame.fillna : Replace missing values.
Series.dropna : Drop missing values.
Index.dropna : Drop missing indices.
Examples
--------
>>> df = pd.DataFrame({"name": ['Alfred', 'Batman', 'Catwoman'],
... "toy": [np.nan, 'Batmobile', 'Bullwhip'],
... "born": [pd.NaT, pd.Timestamp("1940-04-25"),
... pd.NaT]})
>>> df
name toy born
0 Alfred NaN NaT
1 Batman Batmobile 1940-04-25
2 Catwoman Bullwhip NaT
Drop the rows where at least one element is missing.
>>> df.dropna()
name toy born
1 Batman Batmobile 1940-04-25
Drop the columns where at least one element is missing.
>>> df.dropna(axis='columns')
name
0 Alfred
1 Batman
2 Catwoman
Drop the rows where all elements are missing.
>>> df.dropna(how='all')
name toy born
0 Alfred NaN NaT
1 Batman Batmobile 1940-04-25
2 Catwoman Bullwhip NaT
Keep only the rows with at least 2 non-NA values.
>>> df.dropna(thresh=2)
name toy born
1 Batman Batmobile 1940-04-25
2 Catwoman Bullwhip NaT
Define in which columns to look for missing values.
>>> df.dropna(subset=['name', 'born'])
name toy born
1 Batman Batmobile 1940-04-25
Keep the DataFrame with valid entries in the same variable.
>>> df.dropna(inplace=True)
>>> df
name toy born
1 Batman Batmobile 1940-04-25
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if isinstance(axis, (tuple, list)):
# GH20987
raise TypeError("supplying multiple axes to axis is no longer supported.")
axis = self._get_axis_number(axis)
agg_axis = 1 - axis
agg_obj = self
if subset is not None:
ax = self._get_axis(agg_axis)
indices = ax.get_indexer_for(subset)
check = indices == -1
if check.any():
raise KeyError(list(np.compress(check, subset)))
agg_obj = self.take(indices, axis=agg_axis)
count = agg_obj.count(axis=agg_axis)
if thresh is not None:
mask = count >= thresh
elif how == "any":
mask = count == len(agg_obj._get_axis(agg_axis))
elif how == "all":
mask = count > 0
else:
if how is not None:
raise ValueError(f"invalid how option: {how}")
else:
raise TypeError("must specify how or thresh")
result = self.loc(axis=axis)[mask]
if inplace:
self._update_inplace(result)
else:
return result
def drop_duplicates(
self,
subset: Optional[Union[Hashable, Sequence[Hashable]]] = None,
keep: Union[str, bool] = "first",
inplace: bool = False,
ignore_index: bool = False,
) -> Optional["DataFrame"]:
"""
Return DataFrame with duplicate rows removed.
Considering certain columns is optional. Indexes, including time indexes
are ignored.
Parameters
----------
subset : column label or sequence of labels, optional
Only consider certain columns for identifying duplicates, by
default use all of the columns.
keep : {'first', 'last', False}, default 'first'
Determines which duplicates (if any) to keep.
- ``first`` : Drop duplicates except for the first occurrence.
- ``last`` : Drop duplicates except for the last occurrence.
- False : Drop all duplicates.
inplace : bool, default False
Whether to drop duplicates in place or to return a copy.
ignore_index : bool, default False
If True, the resulting axis will be labeled 0, 1, …, n - 1.
.. versionadded:: 1.0.0
Returns
-------
DataFrame
DataFrame with duplicates removed or None if ``inplace=True``.
See Also
--------
DataFrame.value_counts: Count unique combinations of columns.
"""
if self.empty:
return self.copy()
inplace = validate_bool_kwarg(inplace, "inplace")
duplicated = self.duplicated(subset, keep=keep)
if inplace:
(inds,) = np.asarray(-duplicated).nonzero()
new_data = self._data.take(inds)
if ignore_index:
new_data.axes[1] = ibase.default_index(len(inds))
self._update_inplace(new_data)
else:
result = self[-duplicated]
if ignore_index:
result.index = ibase.default_index(len(result))
return result
return None
def duplicated(
self,
subset: Optional[Union[Hashable, Sequence[Hashable]]] = None,
keep: Union[str, bool] = "first",
) -> "Series":
"""
Return boolean Series denoting duplicate rows.
Considering certain columns is optional.
Parameters
----------
subset : column label or sequence of labels, optional
Only consider certain columns for identifying duplicates, by
default use all of the columns.
keep : {'first', 'last', False}, default 'first'
Determines which duplicates (if any) to mark.
- ``first`` : Mark duplicates as ``True`` except for the first occurrence.
- ``last`` : Mark duplicates as ``True`` except for the last occurrence.
- False : Mark all duplicates as ``True``.
Returns
-------
Series
"""
from pandas.core.sorting import get_group_index
from pandas._libs.hashtable import duplicated_int64, _SIZE_HINT_LIMIT
if self.empty:
return Series(dtype=bool)
def f(vals):
labels, shape = algorithms.factorize(
vals, size_hint=min(len(self), _SIZE_HINT_LIMIT)
)
return labels.astype("i8", copy=False), len(shape)
if subset is None:
subset = self.columns
elif (
not np.iterable(subset)
or isinstance(subset, str)
or isinstance(subset, tuple)
and subset in self.columns
):
subset = (subset,)
# needed for mypy since can't narrow types using np.iterable
subset = cast(Iterable, subset)
# Verify all columns in subset exist in the queried dataframe
# Otherwise, raise a KeyError, same as if you try to __getitem__ with a
# key that doesn't exist.
diff = Index(subset).difference(self.columns)
if not diff.empty:
raise KeyError(diff)
vals = (col.values for name, col in self.items() if name in subset)
labels, shape = map(list, zip(*map(f, vals)))
ids = get_group_index(labels, shape, sort=False, xnull=False)
return Series(duplicated_int64(ids, keep), index=self.index)
# ----------------------------------------------------------------------
# Sorting
@Substitution(**_shared_doc_kwargs)
@Appender(NDFrame.sort_values.__doc__)
def sort_values(
self,
by,
axis=0,
ascending=True,
inplace=False,
kind="quicksort",
na_position="last",
ignore_index=False,
):
inplace = validate_bool_kwarg(inplace, "inplace")
axis = self._get_axis_number(axis)
if not isinstance(by, list):
by = [by]
if is_sequence(ascending) and len(by) != len(ascending):
raise ValueError(
f"Length of ascending ({len(ascending)}) != length of by ({len(by)})"
)
if len(by) > 1:
from pandas.core.sorting import lexsort_indexer
keys = [self._get_label_or_level_values(x, axis=axis) for x in by]
indexer = lexsort_indexer(keys, orders=ascending, na_position=na_position)
indexer = ensure_platform_int(indexer)
else:
from pandas.core.sorting import nargsort
by = by[0]
k = self._get_label_or_level_values(by, axis=axis)
if isinstance(ascending, (tuple, list)):
ascending = ascending[0]
indexer = nargsort(
k, kind=kind, ascending=ascending, na_position=na_position
)
new_data = self._data.take(
indexer, axis=self._get_block_manager_axis(axis), verify=False
)
if ignore_index:
new_data.axes[1] = ibase.default_index(len(indexer))
if inplace:
return self._update_inplace(new_data)
else:
return self._constructor(new_data).__finalize__(self)
def sort_index(
self,
axis=0,
level=None,
ascending: bool = True,
inplace: bool = False,
kind: str = "quicksort",
na_position: str = "last",
sort_remaining: bool = True,
ignore_index: bool = False,
):
"""
Sort object by labels (along an axis).
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis along which to sort. The value 0 identifies the rows,
and 1 identifies the columns.
level : int or level name or list of ints or list of level names
If not None, sort on values in specified index level(s).
ascending : bool or list of bools, default True
Sort ascending vs. descending. When the index is a MultiIndex the
sort direction can be controlled for each level individually.
inplace : bool, default False
If True, perform operation in-place.
kind : {'quicksort', 'mergesort', 'heapsort'}, default 'quicksort'
Choice of sorting algorithm. See also ndarray.np.sort for more
information. `mergesort` is the only stable algorithm. For
DataFrames, this option is only applied when sorting on a single
column or label.
na_position : {'first', 'last'}, default 'last'
Puts NaNs at the beginning if `first`; `last` puts NaNs at the end.
Not implemented for MultiIndex.
sort_remaining : bool, default True
If True and sorting by level and index is multilevel, sort by other
levels too (in order) after sorting by specified level.
ignore_index : bool, default False
If True, the resulting axis will be labeled 0, 1, …, n - 1.
.. versionadded:: 1.0.0
Returns
-------
sorted_obj : DataFrame or None
DataFrame with sorted index if inplace=False, None otherwise.
"""
# TODO: this can be combined with Series.sort_index impl as
# almost identical
inplace = validate_bool_kwarg(inplace, "inplace")
axis = self._get_axis_number(axis)
labels = self._get_axis(axis)
# make sure that the axis is lexsorted to start
# if not we need to reconstruct to get the correct indexer
labels = labels._sort_levels_monotonic()
if level is not None:
new_axis, indexer = labels.sortlevel(
level, ascending=ascending, sort_remaining=sort_remaining
)
elif isinstance(labels, ABCMultiIndex):
from pandas.core.sorting import lexsort_indexer
indexer = lexsort_indexer(
labels._get_codes_for_sorting(),
orders=ascending,
na_position=na_position,
)
else:
from pandas.core.sorting import nargsort
# Check monotonic-ness before sort an index
# GH11080
if (ascending and labels.is_monotonic_increasing) or (
not ascending and labels.is_monotonic_decreasing
):
if inplace:
return
else:
return self.copy()
indexer = nargsort(
labels, kind=kind, ascending=ascending, na_position=na_position
)
baxis = self._get_block_manager_axis(axis)
new_data = self._data.take(indexer, axis=baxis, verify=False)
# reconstruct axis if needed
new_data.axes[baxis] = new_data.axes[baxis]._sort_levels_monotonic()
if ignore_index:
new_data.axes[1] = ibase.default_index(len(indexer))
if inplace:
return self._update_inplace(new_data)
else:
return self._constructor(new_data).__finalize__(self)
def value_counts(
self,
subset: Optional[Sequence[Label]] = None,
normalize: bool = False,
sort: bool = True,
ascending: bool = False,
):
"""
Return a Series containing counts of unique rows in the DataFrame.
.. versionadded:: 1.1.0
Parameters
----------
subset : list-like, optional
Columns to use when counting unique combinations.
normalize : bool, default False
Return proportions rather than frequencies.
sort : bool, default True
Sort by frequencies.
ascending : bool, default False
Sort in ascending order.
Returns
-------
Series
See Also
--------
Series.value_counts: Equivalent method on Series.
Notes
-----
The returned Series will have a MultiIndex with one level per input
column. By default, rows that contain any NA values are omitted from
the result. By default, the resulting Series will be in descending
order so that the first element is the most frequently-occurring row.
Examples
--------
>>> df = pd.DataFrame({'num_legs': [2, 4, 4, 6],
... 'num_wings': [2, 0, 0, 0]},
... index=['falcon', 'dog', 'cat', 'ant'])
>>> df
num_legs num_wings
falcon 2 2
dog 4 0
cat 4 0
ant 6 0
>>> df.value_counts()
num_legs num_wings
4 0 2
6 0 1
2 2 1
dtype: int64
>>> df.value_counts(sort=False)
num_legs num_wings
2 2 1
4 0 2
6 0 1
dtype: int64
>>> df.value_counts(ascending=True)
num_legs num_wings
2 2 1
6 0 1
4 0 2
dtype: int64
>>> df.value_counts(normalize=True)
num_legs num_wings
4 0 0.50
6 0 0.25
2 2 0.25
dtype: float64
"""
if subset is None:
subset = self.columns.tolist()
counts = self.groupby(subset).size()
if sort:
counts = counts.sort_values(ascending=ascending)
if normalize:
counts /= counts.sum()
# Force MultiIndex for single column
if len(subset) == 1:
counts.index = MultiIndex.from_arrays(
[counts.index], names=[counts.index.name]
)
return counts
def nlargest(self, n, columns, keep="first") -> "DataFrame":
"""
Return the first `n` rows ordered by `columns` in descending order.
Return the first `n` rows with the largest values in `columns`, in
descending order. The columns that are not specified are returned as
well, but not used for ordering.
This method is equivalent to
``df.sort_values(columns, ascending=False).head(n)``, but more
performant.
Parameters
----------
n : int
Number of rows to return.
columns : label or list of labels
Column label(s) to order by.
keep : {'first', 'last', 'all'}, default 'first'
Where there are duplicate values:
- `first` : prioritize the first occurrence(s)
- `last` : prioritize the last occurrence(s)
- ``all`` : do not drop any duplicates, even it means
selecting more than `n` items.
.. versionadded:: 0.24.0
Returns
-------
DataFrame
The first `n` rows ordered by the given columns in descending
order.
See Also
--------
DataFrame.nsmallest : Return the first `n` rows ordered by `columns` in
ascending order.
DataFrame.sort_values : Sort DataFrame by the values.
DataFrame.head : Return the first `n` rows without re-ordering.
Notes
-----
This function cannot be used with all column types. For example, when
specifying columns with `object` or `category` dtypes, ``TypeError`` is
raised.
Examples
--------
>>> df = pd.DataFrame({'population': [59000000, 65000000, 434000,
... 434000, 434000, 337000, 11300,
... 11300, 11300],
... 'GDP': [1937894, 2583560 , 12011, 4520, 12128,
... 17036, 182, 38, 311],
... 'alpha-2': ["IT", "FR", "MT", "MV", "BN",
... "IS", "NR", "TV", "AI"]},
... index=["Italy", "France", "Malta",
... "Maldives", "Brunei", "Iceland",
... "Nauru", "Tuvalu", "Anguilla"])
>>> df
population GDP alpha-2
Italy 59000000 1937894 IT
France 65000000 2583560 FR
Malta 434000 12011 MT
Maldives 434000 4520 MV
Brunei 434000 12128 BN
Iceland 337000 17036 IS
Nauru 11300 182 NR
Tuvalu 11300 38 TV
Anguilla 11300 311 AI
In the following example, we will use ``nlargest`` to select the three
rows having the largest values in column "population".
>>> df.nlargest(3, 'population')
population GDP alpha-2
France 65000000 2583560 FR
Italy 59000000 1937894 IT
Malta 434000 12011 MT
When using ``keep='last'``, ties are resolved in reverse order:
>>> df.nlargest(3, 'population', keep='last')
population GDP alpha-2
France 65000000 2583560 FR
Italy 59000000 1937894 IT
Brunei 434000 12128 BN
When using ``keep='all'``, all duplicate items are maintained:
>>> df.nlargest(3, 'population', keep='all')
population GDP alpha-2
France 65000000 2583560 FR
Italy 59000000 1937894 IT
Malta 434000 12011 MT
Maldives 434000 4520 MV
Brunei 434000 12128 BN
To order by the largest values in column "population" and then "GDP",
we can specify multiple columns like in the next example.
>>> df.nlargest(3, ['population', 'GDP'])
population GDP alpha-2
France 65000000 2583560 FR
Italy 59000000 1937894 IT
Brunei 434000 12128 BN
"""
return algorithms.SelectNFrame(self, n=n, keep=keep, columns=columns).nlargest()
def nsmallest(self, n, columns, keep="first") -> "DataFrame":
"""
Return the first `n` rows ordered by `columns` in ascending order.
Return the first `n` rows with the smallest values in `columns`, in
ascending order. The columns that are not specified are returned as
well, but not used for ordering.
This method is equivalent to
``df.sort_values(columns, ascending=True).head(n)``, but more
performant.
Parameters
----------
n : int
Number of items to retrieve.
columns : list or str
Column name or names to order by.
keep : {'first', 'last', 'all'}, default 'first'
Where there are duplicate values:
- ``first`` : take the first occurrence.
- ``last`` : take the last occurrence.
- ``all`` : do not drop any duplicates, even it means
selecting more than `n` items.
.. versionadded:: 0.24.0
Returns
-------
DataFrame
See Also
--------
DataFrame.nlargest : Return the first `n` rows ordered by `columns` in
descending order.
DataFrame.sort_values : Sort DataFrame by the values.
DataFrame.head : Return the first `n` rows without re-ordering.
Examples
--------
>>> df = pd.DataFrame({'population': [59000000, 65000000, 434000,
... 434000, 434000, 337000, 337000,
... 11300, 11300],
... 'GDP': [1937894, 2583560 , 12011, 4520, 12128,
... 17036, 182, 38, 311],
... 'alpha-2': ["IT", "FR", "MT", "MV", "BN",
... "IS", "NR", "TV", "AI"]},
... index=["Italy", "France", "Malta",
... "Maldives", "Brunei", "Iceland",
... "Nauru", "Tuvalu", "Anguilla"])
>>> df
population GDP alpha-2
Italy 59000000 1937894 IT
France 65000000 2583560 FR
Malta 434000 12011 MT
Maldives 434000 4520 MV
Brunei 434000 12128 BN
Iceland 337000 17036 IS
Nauru 337000 182 NR
Tuvalu 11300 38 TV
Anguilla 11300 311 AI
In the following example, we will use ``nsmallest`` to select the
three rows having the smallest values in column "population".
>>> df.nsmallest(3, 'population')
population GDP alpha-2
Tuvalu 11300 38 TV
Anguilla 11300 311 AI
Iceland 337000 17036 IS
When using ``keep='last'``, ties are resolved in reverse order:
>>> df.nsmallest(3, 'population', keep='last')
population GDP alpha-2
Anguilla 11300 311 AI
Tuvalu 11300 38 TV
Nauru 337000 182 NR
When using ``keep='all'``, all duplicate items are maintained:
>>> df.nsmallest(3, 'population', keep='all')
population GDP alpha-2
Tuvalu 11300 38 TV
Anguilla 11300 311 AI
Iceland 337000 17036 IS
Nauru 337000 182 NR
To order by the smallest values in column "population" and then "GDP", we can
specify multiple columns like in the next example.
>>> df.nsmallest(3, ['population', 'GDP'])
population GDP alpha-2
Tuvalu 11300 38 TV
Anguilla 11300 311 AI
Nauru 337000 182 NR
"""
return algorithms.SelectNFrame(
self, n=n, keep=keep, columns=columns
).nsmallest()
def swaplevel(self, i=-2, j=-1, axis=0) -> "DataFrame":
"""
Swap levels i and j in a MultiIndex on a particular axis.
Parameters
----------
i, j : int or str
Levels of the indices to be swapped. Can pass level name as string.
Returns
-------
DataFrame
"""
result = self.copy()
axis = self._get_axis_number(axis)
if not isinstance(result._get_axis(axis), ABCMultiIndex): # pragma: no cover
raise TypeError("Can only swap levels on a hierarchical axis.")
if axis == 0:
assert isinstance(result.index, ABCMultiIndex)
result.index = result.index.swaplevel(i, j)
else:
assert isinstance(result.columns, ABCMultiIndex)
result.columns = result.columns.swaplevel(i, j)
return result
def reorder_levels(self, order, axis=0) -> "DataFrame":
"""
Rearrange index levels using input order. May not drop or duplicate levels.
Parameters
----------
order : list of int or list of str
List representing new level order. Reference level by number
(position) or by key (label).
axis : int
Where to reorder levels.
Returns
-------
DataFrame
"""
axis = self._get_axis_number(axis)
if not isinstance(self._get_axis(axis), ABCMultiIndex): # pragma: no cover
raise TypeError("Can only reorder levels on a hierarchical axis.")
result = self.copy()
if axis == 0:
assert isinstance(result.index, ABCMultiIndex)
result.index = result.index.reorder_levels(order)
else:
assert isinstance(result.columns, ABCMultiIndex)
result.columns = result.columns.reorder_levels(order)
return result
# ----------------------------------------------------------------------
# Arithmetic / combination related
def _combine_frame(self, other: "DataFrame", func, fill_value=None):
# at this point we have `self._indexed_same(other)`
if fill_value is None:
# since _arith_op may be called in a loop, avoid function call
# overhead if possible by doing this check once
_arith_op = func
else:
def _arith_op(left, right):
# for the mixed_type case where we iterate over columns,
# _arith_op(left, right) is equivalent to
# left._binop(right, func, fill_value=fill_value)
left, right = ops.fill_binop(left, right, fill_value)
return func(left, right)
if ops.should_series_dispatch(self, other, func):
# iterate over columns
new_data = ops.dispatch_to_series(self, other, _arith_op)
else:
with np.errstate(all="ignore"):
res_values = _arith_op(self.values, other.values)
new_data = dispatch_fill_zeros(func, self.values, other.values, res_values)
return new_data
def _construct_result(self, result) -> "DataFrame":
"""
Wrap the result of an arithmetic, comparison, or logical operation.
Parameters
----------
result : DataFrame
Returns
-------
DataFrame
"""
out = self._constructor(result, index=self.index, copy=False)
# Pin columns instead of passing to constructor for compat with
# non-unique columns case
out.columns = self.columns
return out
def combine(
self, other: "DataFrame", func, fill_value=None, overwrite=True
) -> "DataFrame":
"""
Perform column-wise combine with another DataFrame.
Combines a DataFrame with `other` DataFrame using `func`
to element-wise combine columns. The row and column indexes of the
resulting DataFrame will be the union of the two.
Parameters
----------
other : DataFrame
The DataFrame to merge column-wise.
func : function
Function that takes two series as inputs and return a Series or a
scalar. Used to merge the two dataframes column by columns.
fill_value : scalar value, default None
The value to fill NaNs with prior to passing any column to the
merge func.
overwrite : bool, default True
If True, columns in `self` that do not exist in `other` will be
overwritten with NaNs.
Returns
-------
DataFrame
Combination of the provided DataFrames.
See Also
--------
DataFrame.combine_first : Combine two DataFrame objects and default to
non-null values in frame calling the method.
Examples
--------
Combine using a simple function that chooses the smaller column.
>>> df1 = pd.DataFrame({'A': [0, 0], 'B': [4, 4]})
>>> df2 = pd.DataFrame({'A': [1, 1], 'B': [3, 3]})
>>> take_smaller = lambda s1, s2: s1 if s1.sum() < s2.sum() else s2
>>> df1.combine(df2, take_smaller)
A B
0 0 3
1 0 3
Example using a true element-wise combine function.
>>> df1 = pd.DataFrame({'A': [5, 0], 'B': [2, 4]})
>>> df2 = pd.DataFrame({'A': [1, 1], 'B': [3, 3]})
>>> df1.combine(df2, np.minimum)
A B
0 1 2
1 0 3
Using `fill_value` fills Nones prior to passing the column to the
merge function.
>>> df1 = pd.DataFrame({'A': [0, 0], 'B': [None, 4]})
>>> df2 = pd.DataFrame({'A': [1, 1], 'B': [3, 3]})
>>> df1.combine(df2, take_smaller, fill_value=-5)
A B
0 0 -5.0
1 0 4.0
However, if the same element in both dataframes is None, that None
is preserved
>>> df1 = pd.DataFrame({'A': [0, 0], 'B': [None, 4]})
>>> df2 = pd.DataFrame({'A': [1, 1], 'B': [None, 3]})
>>> df1.combine(df2, take_smaller, fill_value=-5)
A B
0 0 -5.0
1 0 3.0
Example that demonstrates the use of `overwrite` and behavior when
the axis differ between the dataframes.
>>> df1 = pd.DataFrame({'A': [0, 0], 'B': [4, 4]})
>>> df2 = pd.DataFrame({'B': [3, 3], 'C': [-10, 1], }, index=[1, 2])
>>> df1.combine(df2, take_smaller)
A B C
0 NaN NaN NaN
1 NaN 3.0 -10.0
2 NaN 3.0 1.0
>>> df1.combine(df2, take_smaller, overwrite=False)
A B C
0 0.0 NaN NaN
1 0.0 3.0 -10.0
2 NaN 3.0 1.0
Demonstrating the preference of the passed in dataframe.
>>> df2 = pd.DataFrame({'B': [3, 3], 'C': [1, 1], }, index=[1, 2])
>>> df2.combine(df1, take_smaller)
A B C
0 0.0 NaN NaN
1 0.0 3.0 NaN
2 NaN 3.0 NaN
>>> df2.combine(df1, take_smaller, overwrite=False)
A B C
0 0.0 NaN NaN
1 0.0 3.0 1.0
2 NaN 3.0 1.0
"""
other_idxlen = len(other.index) # save for compare
this, other = self.align(other, copy=False)
new_index = this.index
if other.empty and len(new_index) == len(self.index):
return self.copy()
if self.empty and len(other) == other_idxlen:
return other.copy()
# sorts if possible
new_columns = this.columns.union(other.columns)
do_fill = fill_value is not None
result = {}
for col in new_columns:
series = this[col]
otherSeries = other[col]
this_dtype = series.dtype
other_dtype = otherSeries.dtype
this_mask = isna(series)
other_mask = isna(otherSeries)
# don't overwrite columns unnecessarily
# DO propagate if this column is not in the intersection
if not overwrite and other_mask.all():
result[col] = this[col].copy()
continue
if do_fill:
series = series.copy()
otherSeries = otherSeries.copy()
series[this_mask] = fill_value
otherSeries[other_mask] = fill_value
if col not in self.columns:
# If self DataFrame does not have col in other DataFrame,
# try to promote series, which is all NaN, as other_dtype.
new_dtype = other_dtype
try:
series = series.astype(new_dtype, copy=False)
except ValueError:
# e.g. new_dtype is integer types
pass
else:
# if we have different dtypes, possibly promote
new_dtype = find_common_type([this_dtype, other_dtype])
if not is_dtype_equal(this_dtype, new_dtype):
series = series.astype(new_dtype)
if not is_dtype_equal(other_dtype, new_dtype):
otherSeries = otherSeries.astype(new_dtype)
arr = func(series, otherSeries)
arr = maybe_downcast_to_dtype(arr, this_dtype)
result[col] = arr
# convert_objects just in case
return self._constructor(result, index=new_index, columns=new_columns)
def combine_first(self, other: "DataFrame") -> "DataFrame":
"""
Update null elements with value in the same location in `other`.
Combine two DataFrame objects by filling null values in one DataFrame
with non-null values from other DataFrame. The row and column indexes
of the resulting DataFrame will be the union of the two.
Parameters
----------
other : DataFrame
Provided DataFrame to use to fill null values.
Returns
-------
DataFrame
See Also
--------
DataFrame.combine : Perform series-wise operation on two DataFrames
using a given function.
Examples
--------
>>> df1 = pd.DataFrame({'A': [None, 0], 'B': [None, 4]})
>>> df2 = pd.DataFrame({'A': [1, 1], 'B': [3, 3]})
>>> df1.combine_first(df2)
A B
0 1.0 3.0
1 0.0 4.0
Null values still persist if the location of that null value
does not exist in `other`
>>> df1 = pd.DataFrame({'A': [None, 0], 'B': [4, None]})
>>> df2 = pd.DataFrame({'B': [3, 3], 'C': [1, 1]}, index=[1, 2])
>>> df1.combine_first(df2)
A B C
0 NaN 4.0 NaN
1 0.0 3.0 1.0
2 NaN 3.0 1.0
"""
import pandas.core.computation.expressions as expressions
def extract_values(arr):
# Does two things:
# 1. maybe gets the values from the Series / Index
# 2. convert datelike to i8
if isinstance(arr, (ABCIndexClass, ABCSeries)):
arr = arr._values
if needs_i8_conversion(arr):
if is_extension_array_dtype(arr.dtype):
arr = arr.asi8
else:
arr = arr.view("i8")
return arr
def combiner(x, y):
mask = isna(x)
if isinstance(mask, (ABCIndexClass, ABCSeries)):
mask = mask._values
x_values = extract_values(x)
y_values = extract_values(y)
# If the column y in other DataFrame is not in first DataFrame,
# just return y_values.
if y.name not in self.columns:
return y_values
return expressions.where(mask, y_values, x_values)
return self.combine(other, combiner, overwrite=False)
def update(
self, other, join="left", overwrite=True, filter_func=None, errors="ignore"
) -> None:
"""
Modify in place using non-NA values from another DataFrame.
Aligns on indices. There is no return value.
Parameters
----------
other : DataFrame, or object coercible into a DataFrame
Should have at least one matching index/column label
with the original DataFrame. If a Series is passed,
its name attribute must be set, and that will be
used as the column name to align with the original DataFrame.
join : {'left'}, default 'left'
Only left join is implemented, keeping the index and columns of the
original object.
overwrite : bool, default True
How to handle non-NA values for overlapping keys:
* True: overwrite original DataFrame's values
with values from `other`.
* False: only update values that are NA in
the original DataFrame.
filter_func : callable(1d-array) -> bool 1d-array, optional
Can choose to replace values other than NA. Return True for values
that should be updated.
errors : {'raise', 'ignore'}, default 'ignore'
If 'raise', will raise a ValueError if the DataFrame and `other`
both contain non-NA data in the same place.
.. versionchanged:: 0.24.0
Changed from `raise_conflict=False|True`
to `errors='ignore'|'raise'`.
Returns
-------
None : method directly changes calling object
Raises
------
ValueError
* When `errors='raise'` and there's overlapping non-NA data.
* When `errors` is not either `'ignore'` or `'raise'`
NotImplementedError
* If `join != 'left'`
See Also
--------
dict.update : Similar method for dictionaries.
DataFrame.merge : For column(s)-on-columns(s) operations.
Examples
--------
>>> df = pd.DataFrame({'A': [1, 2, 3],
... 'B': [400, 500, 600]})
>>> new_df = pd.DataFrame({'B': [4, 5, 6],
... 'C': [7, 8, 9]})
>>> df.update(new_df)
>>> df
A B
0 1 4
1 2 5
2 3 6
The DataFrame's length does not increase as a result of the update,
only values at matching index/column labels are updated.
>>> df = pd.DataFrame({'A': ['a', 'b', 'c'],
... 'B': ['x', 'y', 'z']})
>>> new_df = pd.DataFrame({'B': ['d', 'e', 'f', 'g', 'h', 'i']})
>>> df.update(new_df)
>>> df
A B
0 a d
1 b e
2 c f
For Series, it's name attribute must be set.
>>> df = pd.DataFrame({'A': ['a', 'b', 'c'],
... 'B': ['x', 'y', 'z']})
>>> new_column = pd.Series(['d', 'e'], name='B', index=[0, 2])
>>> df.update(new_column)
>>> df
A B
0 a d
1 b y
2 c e
>>> df = pd.DataFrame({'A': ['a', 'b', 'c'],
... 'B': ['x', 'y', 'z']})
>>> new_df = pd.DataFrame({'B': ['d', 'e']}, index=[1, 2])
>>> df.update(new_df)
>>> df
A B
0 a x
1 b d
2 c e
If `other` contains NaNs the corresponding values are not updated
in the original dataframe.
>>> df = pd.DataFrame({'A': [1, 2, 3],
... 'B': [400, 500, 600]})
>>> new_df = pd.DataFrame({'B': [4, np.nan, 6]})
>>> df.update(new_df)
>>> df
A B
0 1 4.0
1 2 500.0
2 3 6.0
"""
import pandas.core.computation.expressions as expressions
# TODO: Support other joins
if join != "left": # pragma: no cover
raise NotImplementedError("Only left join is supported")
if errors not in ["ignore", "raise"]:
raise ValueError("The parameter errors must be either 'ignore' or 'raise'")
if not isinstance(other, DataFrame):
other = DataFrame(other)
other = other.reindex_like(self)
for col in self.columns:
this = self[col]._values
that = other[col]._values
if filter_func is not None:
with np.errstate(all="ignore"):
mask = ~filter_func(this) | isna(that)
else:
if errors == "raise":
mask_this = notna(that)
mask_that = notna(this)
if any(mask_this & mask_that):
raise ValueError("Data overlaps.")
if overwrite:
mask = isna(that)
else:
mask = notna(this)
# don't overwrite columns unnecessarily
if mask.all():
continue
self[col] = expressions.where(mask, this, that)
# ----------------------------------------------------------------------
# Data reshaping
@Appender(
"""
Examples
--------
>>> df = pd.DataFrame({'Animal': ['Falcon', 'Falcon',
... 'Parrot', 'Parrot'],
... 'Max Speed': [380., 370., 24., 26.]})
>>> df
Animal Max Speed
0 Falcon 380.0
1 Falcon 370.0
2 Parrot 24.0
3 Parrot 26.0
>>> df.groupby(['Animal']).mean()
Max Speed
Animal
Falcon 375.0
Parrot 25.0
**Hierarchical Indexes**
We can groupby different levels of a hierarchical index
using the `level` parameter:
>>> arrays = [['Falcon', 'Falcon', 'Parrot', 'Parrot'],
... ['Captive', 'Wild', 'Captive', 'Wild']]
>>> index = pd.MultiIndex.from_arrays(arrays, names=('Animal', 'Type'))
>>> df = pd.DataFrame({'Max Speed': [390., 350., 30., 20.]},
... index=index)
>>> df
Max Speed
Animal Type
Falcon Captive 390.0
Wild 350.0
Parrot Captive 30.0
Wild 20.0
>>> df.groupby(level=0).mean()
Max Speed
Animal
Falcon 370.0
Parrot 25.0
>>> df.groupby(level="Type").mean()
Max Speed
Type
Captive 210.0
Wild 185.0
"""
)
@Appender(_shared_docs["groupby"] % _shared_doc_kwargs)
def groupby(
self,
by=None,
axis=0,
level=None,
as_index: bool = True,
sort: bool = True,
group_keys: bool = True,
squeeze: bool = False,
observed: bool = False,
) -> "DataFrameGroupBy":
from pandas.core.groupby.generic import DataFrameGroupBy
if level is None and by is None:
raise TypeError("You have to supply one of 'by' and 'level'")
axis = self._get_axis_number(axis)
return DataFrameGroupBy(
obj=self,
keys=by,
axis=axis,
level=level,
as_index=as_index,
sort=sort,
group_keys=group_keys,
squeeze=squeeze,
observed=observed,
)
_shared_docs[
"pivot"
] = """
Return reshaped DataFrame organized by given index / column values.
Reshape data (produce a "pivot" table) based on column values. Uses
unique values from specified `index` / `columns` to form axes of the
resulting DataFrame. This function does not support data
aggregation, multiple values will result in a MultiIndex in the
columns. See the :ref:`User Guide <reshaping>` for more on reshaping.
Parameters
----------%s
index : str or object or a list of str, optional
Column to use to make new frame's index. If None, uses
existing index.
.. versionchanged:: 1.1.0
Also accept list of index names.
columns : str or object or a list of str
Column to use to make new frame's columns.
.. versionchanged:: 1.1.0
Also accept list of columns names.
values : str, object or a list of the previous, optional
Column(s) to use for populating new frame's values. If not
specified, all remaining columns will be used and the result will
have hierarchically indexed columns.
.. versionchanged:: 0.23.0
Also accept list of column names.
Returns
-------
DataFrame
Returns reshaped DataFrame.
Raises
------
ValueError:
When there are any `index`, `columns` combinations with multiple
values. `DataFrame.pivot_table` when you need to aggregate.
See Also
--------
DataFrame.pivot_table : Generalization of pivot that can handle
duplicate values for one index/column pair.
DataFrame.unstack : Pivot based on the index values instead of a
column.
Notes
-----
For finer-tuned control, see hierarchical indexing documentation along
with the related stack/unstack methods.
Examples
--------
>>> df = pd.DataFrame({'foo': ['one', 'one', 'one', 'two', 'two',
... 'two'],
... 'bar': ['A', 'B', 'C', 'A', 'B', 'C'],
... 'baz': [1, 2, 3, 4, 5, 6],
... 'zoo': ['x', 'y', 'z', 'q', 'w', 't']})
>>> df
foo bar baz zoo
0 one A 1 x
1 one B 2 y
2 one C 3 z
3 two A 4 q
4 two B 5 w
5 two C 6 t
>>> df.pivot(index='foo', columns='bar', values='baz')
bar A B C
foo
one 1 2 3
two 4 5 6
>>> df.pivot(index='foo', columns='bar')['baz']
bar A B C
foo
one 1 2 3
two 4 5 6
>>> df.pivot(index='foo', columns='bar', values=['baz', 'zoo'])
baz zoo
bar A B C A B C
foo
one 1 2 3 x y z
two 4 5 6 q w t
You could also assign a list of column names or a list of index names.
>>> df = pd.DataFrame({
... "lev1": [1, 1, 1, 2, 2, 2],
... "lev2": [1, 1, 2, 1, 1, 2],
... "lev3": [1, 2, 1, 2, 1, 2],
... "lev4": [1, 2, 3, 4, 5, 6],
... "values": [0, 1, 2, 3, 4, 5]})
>>> df
lev1 lev2 lev3 lev4 values
0 1 1 1 1 0
1 1 1 2 2 1
2 1 2 1 3 2
3 2 1 2 4 3
4 2 1 1 5 4
5 2 2 2 6 5
>>> df.pivot(index="lev1", columns=["lev2", "lev3"],values="values")
lev2 1 2
lev3 1 2 1 2
lev1
1 0.0 1.0 2.0 NaN
2 4.0 3.0 NaN 5.0
>>> df.pivot(index=["lev1", "lev2"], columns=["lev3"],values="values")
lev3 1 2
lev1 lev2
1 1 0.0 1.0
2 2.0 NaN
2 1 4.0 3.0
2 NaN 5.0
A ValueError is raised if there are any duplicates.
>>> df = pd.DataFrame({"foo": ['one', 'one', 'two', 'two'],
... "bar": ['A', 'A', 'B', 'C'],
... "baz": [1, 2, 3, 4]})
>>> df
foo bar baz
0 one A 1
1 one A 2
2 two B 3
3 two C 4
Notice that the first two rows are the same for our `index`
and `columns` arguments.
>>> df.pivot(index='foo', columns='bar', values='baz')
Traceback (most recent call last):
...
ValueError: Index contains duplicate entries, cannot reshape
"""
@Substitution("")
@Appender(_shared_docs["pivot"])
def pivot(self, index=None, columns=None, values=None) -> "DataFrame":
from pandas.core.reshape.pivot import pivot
return pivot(self, index=index, columns=columns, values=values)
_shared_docs[
"pivot_table"
] = """
Create a spreadsheet-style pivot table as a DataFrame.
The levels in the pivot table will be stored in MultiIndex objects
(hierarchical indexes) on the index and columns of the result DataFrame.
Parameters
----------%s
values : column to aggregate, optional
index : column, Grouper, array, or list of the previous
If an array is passed, it must be the same length as the data. The
list can contain any of the other types (except list).
Keys to group by on the pivot table index. If an array is passed,
it is being used as the same manner as column values.
columns : column, Grouper, array, or list of the previous
If an array is passed, it must be the same length as the data. The
list can contain any of the other types (except list).
Keys to group by on the pivot table column. If an array is passed,
it is being used as the same manner as column values.
aggfunc : function, list of functions, dict, default numpy.mean
If list of functions passed, the resulting pivot table will have
hierarchical columns whose top level are the function names
(inferred from the function objects themselves)
If dict is passed, the key is column to aggregate and value
is function or list of functions.
fill_value : scalar, default None
Value to replace missing values with (in the resulting pivot table,
after aggregation).
margins : bool, default False
Add all row / columns (e.g. for subtotal / grand totals).
dropna : bool, default True
Do not include columns whose entries are all NaN.
margins_name : str, default 'All'
Name of the row / column that will contain the totals
when margins is True.
observed : bool, default False
This only applies if any of the groupers are Categoricals.
If True: only show observed values for categorical groupers.
If False: show all values for categorical groupers.
.. versionchanged:: 0.25.0
Returns
-------
DataFrame
An Excel style pivot table.
See Also
--------
DataFrame.pivot : Pivot without aggregation that can handle
non-numeric data.
Examples
--------
>>> df = pd.DataFrame({"A": ["foo", "foo", "foo", "foo", "foo",
... "bar", "bar", "bar", "bar"],
... "B": ["one", "one", "one", "two", "two",
... "one", "one", "two", "two"],
... "C": ["small", "large", "large", "small",
... "small", "large", "small", "small",
... "large"],
... "D": [1, 2, 2, 3, 3, 4, 5, 6, 7],
... "E": [2, 4, 5, 5, 6, 6, 8, 9, 9]})
>>> df
A B C D E
0 foo one small 1 2
1 foo one large 2 4
2 foo one large 2 5
3 foo two small 3 5
4 foo two small 3 6
5 bar one large 4 6
6 bar one small 5 8
7 bar two small 6 9
8 bar two large 7 9
This first example aggregates values by taking the sum.
>>> table = pd.pivot_table(df, values='D', index=['A', 'B'],
... columns=['C'], aggfunc=np.sum)
>>> table
C large small
A B
bar one 4.0 5.0
two 7.0 6.0
foo one 4.0 1.0
two NaN 6.0
We can also fill missing values using the `fill_value` parameter.
>>> table = pd.pivot_table(df, values='D', index=['A', 'B'],
... columns=['C'], aggfunc=np.sum, fill_value=0)
>>> table
C large small
A B
bar one 4 5
two 7 6
foo one 4 1
two 0 6
The next example aggregates by taking the mean across multiple columns.
>>> table = pd.pivot_table(df, values=['D', 'E'], index=['A', 'C'],
... aggfunc={'D': np.mean,
... 'E': np.mean})
>>> table
D E
A C
bar large 5.500000 7.500000
small 5.500000 8.500000
foo large 2.000000 4.500000
small 2.333333 4.333333
We can also calculate multiple types of aggregations for any given
value column.
>>> table = pd.pivot_table(df, values=['D', 'E'], index=['A', 'C'],
... aggfunc={'D': np.mean,
... 'E': [min, max, np.mean]})
>>> table
D E
mean max mean min
A C
bar large 5.500000 9.0 7.500000 6.0
small 5.500000 9.0 8.500000 8.0
foo large 2.000000 5.0 4.500000 4.0
small 2.333333 6.0 4.333333 2.0
"""
@Substitution("")
@Appender(_shared_docs["pivot_table"])
def pivot_table(
self,
values=None,
index=None,
columns=None,
aggfunc="mean",
fill_value=None,
margins=False,
dropna=True,
margins_name="All",
observed=False,
) -> "DataFrame":
from pandas.core.reshape.pivot import pivot_table
return pivot_table(
self,
values=values,
index=index,
columns=columns,
aggfunc=aggfunc,
fill_value=fill_value,
margins=margins,
dropna=dropna,
margins_name=margins_name,
observed=observed,
)
def stack(self, level=-1, dropna=True):
"""
Stack the prescribed level(s) from columns to index.
Return a reshaped DataFrame or Series having a multi-level
index with one or more new inner-most levels compared to the current
DataFrame. The new inner-most levels are created by pivoting the
columns of the current dataframe:
- if the columns have a single level, the output is a Series;
- if the columns have multiple levels, the new index
level(s) is (are) taken from the prescribed level(s) and
the output is a DataFrame.
The new index levels are sorted.
Parameters
----------
level : int, str, list, default -1
Level(s) to stack from the column axis onto the index
axis, defined as one index or label, or a list of indices
or labels.
dropna : bool, default True
Whether to drop rows in the resulting Frame/Series with
missing values. Stacking a column level onto the index
axis can create combinations of index and column values
that are missing from the original dataframe. See Examples
section.
Returns
-------
DataFrame or Series
Stacked dataframe or series.
See Also
--------
DataFrame.unstack : Unstack prescribed level(s) from index axis
onto column axis.
DataFrame.pivot : Reshape dataframe from long format to wide
format.
DataFrame.pivot_table : Create a spreadsheet-style pivot table
as a DataFrame.
Notes
-----
The function is named by analogy with a collection of books
being reorganized from being side by side on a horizontal
position (the columns of the dataframe) to being stacked
vertically on top of each other (in the index of the
dataframe).
Examples
--------
**Single level columns**
>>> df_single_level_cols = pd.DataFrame([[0, 1], [2, 3]],
... index=['cat', 'dog'],
... columns=['weight', 'height'])
Stacking a dataframe with a single level column axis returns a Series:
>>> df_single_level_cols
weight height
cat 0 1
dog 2 3
>>> df_single_level_cols.stack()
cat weight 0
height 1
dog weight 2
height 3
dtype: int64
**Multi level columns: simple case**
>>> multicol1 = pd.MultiIndex.from_tuples([('weight', 'kg'),
... ('weight', 'pounds')])
>>> df_multi_level_cols1 = pd.DataFrame([[1, 2], [2, 4]],
... index=['cat', 'dog'],
... columns=multicol1)
Stacking a dataframe with a multi-level column axis:
>>> df_multi_level_cols1
weight
kg pounds
cat 1 2
dog 2 4
>>> df_multi_level_cols1.stack()
weight
cat kg 1
pounds 2
dog kg 2
pounds 4
**Missing values**
>>> multicol2 = pd.MultiIndex.from_tuples([('weight', 'kg'),
... ('height', 'm')])
>>> df_multi_level_cols2 = pd.DataFrame([[1.0, 2.0], [3.0, 4.0]],
... index=['cat', 'dog'],
... columns=multicol2)
It is common to have missing values when stacking a dataframe
with multi-level columns, as the stacked dataframe typically
has more values than the original dataframe. Missing values
are filled with NaNs:
>>> df_multi_level_cols2
weight height
kg m
cat 1.0 2.0
dog 3.0 4.0
>>> df_multi_level_cols2.stack()
height weight
cat kg NaN 1.0
m 2.0 NaN
dog kg NaN 3.0
m 4.0 NaN
**Prescribing the level(s) to be stacked**
The first parameter controls which level or levels are stacked:
>>> df_multi_level_cols2.stack(0)
kg m
cat height NaN 2.0
weight 1.0 NaN
dog height NaN 4.0
weight 3.0 NaN
>>> df_multi_level_cols2.stack([0, 1])
cat height m 2.0
weight kg 1.0
dog height m 4.0
weight kg 3.0
dtype: float64
**Dropping missing values**
>>> df_multi_level_cols3 = pd.DataFrame([[None, 1.0], [2.0, 3.0]],
... index=['cat', 'dog'],
... columns=multicol2)
Note that rows where all values are missing are dropped by
default but this behaviour can be controlled via the dropna
keyword parameter:
>>> df_multi_level_cols3
weight height
kg m
cat NaN 1.0
dog 2.0 3.0
>>> df_multi_level_cols3.stack(dropna=False)
height weight
cat kg NaN NaN
m 1.0 NaN
dog kg NaN 2.0
m 3.0 NaN
>>> df_multi_level_cols3.stack(dropna=True)
height weight
cat m 1.0 NaN
dog kg NaN 2.0
m 3.0 NaN
"""
from pandas.core.reshape.reshape import stack, stack_multiple
if isinstance(level, (tuple, list)):
return stack_multiple(self, level, dropna=dropna)
else:
return stack(self, level, dropna=dropna)
def explode(self, column: Union[str, Tuple]) -> "DataFrame":
"""
Transform each element of a list-like to a row, replicating index values.
.. versionadded:: 0.25.0
Parameters
----------
column : str or tuple
Column to explode.
Returns
-------
DataFrame
Exploded lists to rows of the subset columns;
index will be duplicated for these rows.
Raises
------
ValueError :
if columns of the frame are not unique.
See Also
--------
DataFrame.unstack : Pivot a level of the (necessarily hierarchical)
index labels.
DataFrame.melt : Unpivot a DataFrame from wide format to long format.
Series.explode : Explode a DataFrame from list-like columns to long format.
Notes
-----
This routine will explode list-likes including lists, tuples,
Series, and np.ndarray. The result dtype of the subset rows will
be object. Scalars will be returned unchanged. Empty list-likes will
result in a np.nan for that row.
Examples
--------
>>> df = pd.DataFrame({'A': [[1, 2, 3], 'foo', [], [3, 4]], 'B': 1})
>>> df
A B
0 [1, 2, 3] 1
1 foo 1
2 [] 1
3 [3, 4] 1
>>> df.explode('A')
A B
0 1 1
0 2 1
0 3 1
1 foo 1
2 NaN 1
3 3 1
3 4 1
"""
if not (is_scalar(column) or isinstance(column, tuple)):
raise ValueError("column must be a scalar")
if not self.columns.is_unique:
raise ValueError("columns must be unique")
df = self.reset_index(drop=True)
# TODO: use overload to refine return type of reset_index
assert df is not None # needed for mypy
result = df[column].explode()
result = df.drop([column], axis=1).join(result)
result.index = self.index.take(result.index)
result = result.reindex(columns=self.columns, copy=False)
return result
def unstack(self, level=-1, fill_value=None):
"""
Pivot a level of the (necessarily hierarchical) index labels.
Returns a DataFrame having a new level of column labels whose inner-most level
consists of the pivoted index labels.
If the index is not a MultiIndex, the output will be a Series
(the analogue of stack when the columns are not a MultiIndex).
The level involved will automatically get sorted.
Parameters
----------
level : int, str, or list of these, default -1 (last level)
Level(s) of index to unstack, can pass level name.
fill_value : int, str or dict
Replace NaN with this value if the unstack produces missing values.
Returns
-------
Series or DataFrame
See Also
--------
DataFrame.pivot : Pivot a table based on column values.
DataFrame.stack : Pivot a level of the column labels (inverse operation
from `unstack`).
Examples
--------
>>> index = pd.MultiIndex.from_tuples([('one', 'a'), ('one', 'b'),
... ('two', 'a'), ('two', 'b')])
>>> s = pd.Series(np.arange(1.0, 5.0), index=index)
>>> s
one a 1.0
b 2.0
two a 3.0
b 4.0
dtype: float64
>>> s.unstack(level=-1)
a b
one 1.0 2.0
two 3.0 4.0
>>> s.unstack(level=0)
one two
a 1.0 3.0
b 2.0 4.0
>>> df = s.unstack(level=0)
>>> df.unstack()
one a 1.0
b 2.0
two a 3.0
b 4.0
dtype: float64
"""
from pandas.core.reshape.reshape import unstack
return unstack(self, level, fill_value)
_shared_docs[
"melt"
] = """
Unpivot a DataFrame from wide to long format, optionally leaving identifiers set.
This function is useful to massage a DataFrame into a format where one
or more columns are identifier variables (`id_vars`), while all other
columns, considered measured variables (`value_vars`), are "unpivoted" to
the row axis, leaving just two non-identifier columns, 'variable' and
'value'.
%(versionadded)s
Parameters
----------
id_vars : tuple, list, or ndarray, optional
Column(s) to use as identifier variables.
value_vars : tuple, list, or ndarray, optional
Column(s) to unpivot. If not specified, uses all columns that
are not set as `id_vars`.
var_name : scalar
Name to use for the 'variable' column. If None it uses
``frame.columns.name`` or 'variable'.
value_name : scalar, default 'value'
Name to use for the 'value' column.
col_level : int or str, optional
If columns are a MultiIndex then use this level to melt.
Returns
-------
DataFrame
Unpivoted DataFrame.
See Also
--------
%(other)s
pivot_table
DataFrame.pivot
Series.explode
Examples
--------
>>> df = pd.DataFrame({'A': {0: 'a', 1: 'b', 2: 'c'},
... 'B': {0: 1, 1: 3, 2: 5},
... 'C': {0: 2, 1: 4, 2: 6}})
>>> df
A B C
0 a 1 2
1 b 3 4
2 c 5 6
>>> %(caller)sid_vars=['A'], value_vars=['B'])
A variable value
0 a B 1
1 b B 3
2 c B 5
>>> %(caller)sid_vars=['A'], value_vars=['B', 'C'])
A variable value
0 a B 1
1 b B 3
2 c B 5
3 a C 2
4 b C 4
5 c C 6
The names of 'variable' and 'value' columns can be customized:
>>> %(caller)sid_vars=['A'], value_vars=['B'],
... var_name='myVarname', value_name='myValname')
A myVarname myValname
0 a B 1
1 b B 3
2 c B 5
If you have multi-index columns:
>>> df.columns = [list('ABC'), list('DEF')]
>>> df
A B C
D E F
0 a 1 2
1 b 3 4
2 c 5 6
>>> %(caller)scol_level=0, id_vars=['A'], value_vars=['B'])
A variable value
0 a B 1
1 b B 3
2 c B 5
>>> %(caller)sid_vars=[('A', 'D')], value_vars=[('B', 'E')])
(A, D) variable_0 variable_1 value
0 a B E 1
1 b B E 3
2 c B E 5
"""
@Appender(
_shared_docs["melt"]
% dict(
caller="df.melt(",
versionadded="\n .. versionadded:: 0.20.0\n",
other="melt",
)
)
def melt(
self,
id_vars=None,
value_vars=None,
var_name=None,
value_name="value",
col_level=None,
) -> "DataFrame":
from pandas.core.reshape.melt import melt
return melt(
self,
id_vars=id_vars,
value_vars=value_vars,
var_name=var_name,
value_name=value_name,
col_level=col_level,
)
# ----------------------------------------------------------------------
# Time series-related
def diff(self, periods=1, axis=0) -> "DataFrame":
"""
First discrete difference of element.
Calculates the difference of a DataFrame element compared with another
element in the DataFrame (default is the element in the same column
of the previous row).
Parameters
----------
periods : int, default 1
Periods to shift for calculating difference, accepts negative
values.
axis : {0 or 'index', 1 or 'columns'}, default 0
Take difference over rows (0) or columns (1).
Returns
-------
DataFrame
See Also
--------
Series.diff: First discrete difference for a Series.
DataFrame.pct_change: Percent change over given number of periods.
DataFrame.shift: Shift index by desired number of periods with an
optional time freq.
Notes
-----
For boolean dtypes, this uses :meth:`operator.xor` rather than
:meth:`operator.sub`.
Examples
--------
Difference with previous row
>>> df = pd.DataFrame({'a': [1, 2, 3, 4, 5, 6],
... 'b': [1, 1, 2, 3, 5, 8],
... 'c': [1, 4, 9, 16, 25, 36]})
>>> df
a b c
0 1 1 1
1 2 1 4
2 3 2 9
3 4 3 16
4 5 5 25
5 6 8 36
>>> df.diff()
a b c
0 NaN NaN NaN
1 1.0 0.0 3.0
2 1.0 1.0 5.0
3 1.0 1.0 7.0
4 1.0 2.0 9.0
5 1.0 3.0 11.0
Difference with previous column
>>> df.diff(axis=1)
a b c
0 NaN 0.0 0.0
1 NaN -1.0 3.0
2 NaN -1.0 7.0
3 NaN -1.0 13.0
4 NaN 0.0 20.0
5 NaN 2.0 28.0
Difference with 3rd previous row
>>> df.diff(periods=3)
a b c
0 NaN NaN NaN
1 NaN NaN NaN
2 NaN NaN NaN
3 3.0 2.0 15.0
4 3.0 4.0 21.0
5 3.0 6.0 27.0
Difference with following row
>>> df.diff(periods=-1)
a b c
0 -1.0 0.0 -3.0
1 -1.0 -1.0 -5.0
2 -1.0 -1.0 -7.0
3 -1.0 -2.0 -9.0
4 -1.0 -3.0 -11.0
5 NaN NaN NaN
"""
bm_axis = self._get_block_manager_axis(axis)
new_data = self._data.diff(n=periods, axis=bm_axis)
return self._constructor(new_data)
# ----------------------------------------------------------------------
# Function application
def _gotitem(
self,
key: Union[str, List[str]],
ndim: int,
subset: Optional[Union[Series, ABCDataFrame]] = None,
) -> Union[Series, ABCDataFrame]:
"""
Sub-classes to define. Return a sliced object.
Parameters
----------
key : string / list of selections
ndim : 1,2
requested ndim of result
subset : object, default None
subset to act on
"""
if subset is None:
subset = self
elif subset.ndim == 1: # is Series
return subset
# TODO: _shallow_copy(subset)?
return subset[key]
_agg_summary_and_see_also_doc = dedent(
"""
The aggregation operations are always performed over an axis, either the
index (default) or the column axis. This behavior is different from
`numpy` aggregation functions (`mean`, `median`, `prod`, `sum`, `std`,
`var`), where the default is to compute the aggregation of the flattened
array, e.g., ``numpy.mean(arr_2d)`` as opposed to
``numpy.mean(arr_2d, axis=0)``.
`agg` is an alias for `aggregate`. Use the alias.
See Also
--------
DataFrame.apply : Perform any type of operations.
DataFrame.transform : Perform transformation type operations.
core.groupby.GroupBy : Perform operations over groups.
core.resample.Resampler : Perform operations over resampled bins.
core.window.Rolling : Perform operations over rolling window.
core.window.Expanding : Perform operations over expanding window.
core.window.EWM : Perform operation over exponential weighted
window.
"""
)
_agg_examples_doc = dedent(
"""
Examples
--------
>>> df = pd.DataFrame([[1, 2, 3],
... [4, 5, 6],
... [7, 8, 9],
... [np.nan, np.nan, np.nan]],
... columns=['A', 'B', 'C'])
Aggregate these functions over the rows.
>>> df.agg(['sum', 'min'])
A B C
sum 12.0 15.0 18.0
min 1.0 2.0 3.0
Different aggregations per column.
>>> df.agg({'A' : ['sum', 'min'], 'B' : ['min', 'max']})
A B
max NaN 8.0
min 1.0 2.0
sum 12.0 NaN
Aggregate over the columns.
>>> df.agg("mean", axis="columns")
0 2.0
1 5.0
2 8.0
3 NaN
dtype: float64
"""
)
@Substitution(
see_also=_agg_summary_and_see_also_doc,
examples=_agg_examples_doc,
versionadded="\n.. versionadded:: 0.20.0\n",
**_shared_doc_kwargs,
)
@Appender(_shared_docs["aggregate"])
def aggregate(self, func, axis=0, *args, **kwargs):
axis = self._get_axis_number(axis)
result = None
try:
result, how = self._aggregate(func, axis=axis, *args, **kwargs)
except TypeError:
pass
if result is None:
return self.apply(func, axis=axis, args=args, **kwargs)
return result
def _aggregate(self, arg, axis=0, *args, **kwargs):
if axis == 1:
# NDFrame.aggregate returns a tuple, and we need to transpose
# only result
result, how = self.T._aggregate(arg, *args, **kwargs)
result = result.T if result is not None else result
return result, how
return super()._aggregate(arg, *args, **kwargs)
agg = aggregate
@Appender(_shared_docs["transform"] % _shared_doc_kwargs)
def transform(self, func, axis=0, *args, **kwargs) -> "DataFrame":
axis = self._get_axis_number(axis)
if axis == 1:
return self.T.transform(func, *args, **kwargs).T
return super().transform(func, *args, **kwargs)
def apply(self, func, axis=0, raw=False, result_type=None, args=(), **kwds):
"""
Apply a function along an axis of the DataFrame.
Objects passed to the function are Series objects whose index is
either the DataFrame's index (``axis=0``) or the DataFrame's columns
(``axis=1``). By default (``result_type=None``), the final return type
is inferred from the return type of the applied function. Otherwise,
it depends on the `result_type` argument.
Parameters
----------
func : function
Function to apply to each column or row.
axis : {0 or 'index', 1 or 'columns'}, default 0
Axis along which the function is applied:
* 0 or 'index': apply function to each column.
* 1 or 'columns': apply function to each row.
raw : bool, default False
Determines if row or column is passed as a Series or ndarray object:
* ``False`` : passes each row or column as a Series to the
function.
* ``True`` : the passed function will receive ndarray objects
instead.
If you are just applying a NumPy reduction function this will
achieve much better performance.
result_type : {'expand', 'reduce', 'broadcast', None}, default None
These only act when ``axis=1`` (columns):
* 'expand' : list-like results will be turned into columns.
* 'reduce' : returns a Series if possible rather than expanding
list-like results. This is the opposite of 'expand'.
* 'broadcast' : results will be broadcast to the original shape
of the DataFrame, the original index and columns will be
retained.
The default behaviour (None) depends on the return value of the
applied function: list-like results will be returned as a Series
of those. However if the apply function returns a Series these
are expanded to columns.
.. versionadded:: 0.23.0
args : tuple
Positional arguments to pass to `func` in addition to the
array/series.
**kwds
Additional keyword arguments to pass as keywords arguments to
`func`.
Returns
-------
Series or DataFrame
Result of applying ``func`` along the given axis of the
DataFrame.
See Also
--------
DataFrame.applymap: For elementwise operations.
DataFrame.aggregate: Only perform aggregating type operations.
DataFrame.transform: Only perform transforming type operations.
Examples
--------
>>> df = pd.DataFrame([[4, 9]] * 3, columns=['A', 'B'])
>>> df
A B
0 4 9
1 4 9
2 4 9
Using a numpy universal function (in this case the same as
``np.sqrt(df)``):
>>> df.apply(np.sqrt)
A B
0 2.0 3.0
1 2.0 3.0
2 2.0 3.0
Using a reducing function on either axis
>>> df.apply(np.sum, axis=0)
A 12
B 27
dtype: int64
>>> df.apply(np.sum, axis=1)
0 13
1 13
2 13
dtype: int64
Returning a list-like will result in a Series
>>> df.apply(lambda x: [1, 2], axis=1)
0 [1, 2]
1 [1, 2]
2 [1, 2]
dtype: object
Passing result_type='expand' will expand list-like results
to columns of a Dataframe
>>> df.apply(lambda x: [1, 2], axis=1, result_type='expand')
0 1
0 1 2
1 1 2
2 1 2
Returning a Series inside the function is similar to passing
``result_type='expand'``. The resulting column names
will be the Series index.
>>> df.apply(lambda x: pd.Series([1, 2], index=['foo', 'bar']), axis=1)
foo bar
0 1 2
1 1 2
2 1 2
Passing ``result_type='broadcast'`` will ensure the same shape
result, whether list-like or scalar is returned by the function,
and broadcast it along the axis. The resulting column names will
be the originals.
>>> df.apply(lambda x: [1, 2], axis=1, result_type='broadcast')
A B
0 1 2
1 1 2
2 1 2
"""
from pandas.core.apply import frame_apply
op = frame_apply(
self,
func=func,
axis=axis,
raw=raw,
result_type=result_type,
args=args,
kwds=kwds,
)
return op.get_result()
def applymap(self, func) -> "DataFrame":
"""
Apply a function to a Dataframe elementwise.
This method applies a function that accepts and returns a scalar
to every element of a DataFrame.
Parameters
----------
func : callable
Python function, returns a single value from a single value.
Returns
-------
DataFrame
Transformed DataFrame.
See Also
--------
DataFrame.apply : Apply a function along input axis of DataFrame.
Notes
-----
In the current implementation applymap calls `func` twice on the
first column/row to decide whether it can take a fast or slow
code path. This can lead to unexpected behavior if `func` has
side-effects, as they will take effect twice for the first
column/row.
Examples
--------
>>> df = pd.DataFrame([[1, 2.12], [3.356, 4.567]])
>>> df
0 1
0 1.000 2.120
1 3.356 4.567
>>> df.applymap(lambda x: len(str(x)))
0 1
0 3 4
1 5 5
Note that a vectorized version of `func` often exists, which will
be much faster. You could square each number elementwise.
>>> df.applymap(lambda x: x**2)
0 1
0 1.000000 4.494400
1 11.262736 20.857489
But it's better to avoid applymap in that case.
>>> df ** 2
0 1
0 1.000000 4.494400
1 11.262736 20.857489
"""
# if we have a dtype == 'M8[ns]', provide boxed values
def infer(x):
if x.empty:
return lib.map_infer(x, func)
return lib.map_infer(x.astype(object).values, func)
return self.apply(infer)
# ----------------------------------------------------------------------
# Merging / joining methods
def append(
self, other, ignore_index=False, verify_integrity=False, sort=False
) -> "DataFrame":
"""
Append rows of `other` to the end of caller, returning a new object.
Columns in `other` that are not in the caller are added as new columns.
Parameters
----------
other : DataFrame or Series/dict-like object, or list of these
The data to append.
ignore_index : bool, default False
If True, do not use the index labels.
verify_integrity : bool, default False
If True, raise ValueError on creating index with duplicates.
sort : bool, default False
Sort columns if the columns of `self` and `other` are not aligned.
.. versionadded:: 0.23.0
.. versionchanged:: 1.0.0
Changed to not sort by default.
Returns
-------
DataFrame
See Also
--------
concat : General function to concatenate DataFrame or Series objects.
Notes
-----
If a list of dict/series is passed and the keys are all contained in
the DataFrame's index, the order of the columns in the resulting
DataFrame will be unchanged.
Iteratively appending rows to a DataFrame can be more computationally
intensive than a single concatenate. A better solution is to append
those rows to a list and then concatenate the list with the original
DataFrame all at once.
Examples
--------
>>> df = pd.DataFrame([[1, 2], [3, 4]], columns=list('AB'))
>>> df
A B
0 1 2
1 3 4
>>> df2 = pd.DataFrame([[5, 6], [7, 8]], columns=list('AB'))
>>> df.append(df2)
A B
0 1 2
1 3 4
0 5 6
1 7 8
With `ignore_index` set to True:
>>> df.append(df2, ignore_index=True)
A B
0 1 2
1 3 4
2 5 6
3 7 8
The following, while not recommended methods for generating DataFrames,
show two ways to generate a DataFrame from multiple data sources.
Less efficient:
>>> df = pd.DataFrame(columns=['A'])
>>> for i in range(5):
... df = df.append({'A': i}, ignore_index=True)
>>> df
A
0 0
1 1
2 2
3 3
4 4
More efficient:
>>> pd.concat([pd.DataFrame([i], columns=['A']) for i in range(5)],
... ignore_index=True)
A
0 0
1 1
2 2
3 3
4 4
"""
if isinstance(other, (Series, dict)):
if isinstance(other, dict):
if not ignore_index:
raise TypeError("Can only append a dict if ignore_index=True")
other = Series(other)
if other.name is None and not ignore_index:
raise TypeError(
"Can only append a Series if ignore_index=True "
"or if the Series has a name"
)
index = Index([other.name], name=self.index.name)
idx_diff = other.index.difference(self.columns)
try:
combined_columns = self.columns.append(idx_diff)
except TypeError:
combined_columns = self.columns.astype(object).append(idx_diff)
other = (
other.reindex(combined_columns, copy=False)
.to_frame()
.T.infer_objects()
.rename_axis(index.names, copy=False)
)
if not self.columns.equals(combined_columns):
self = self.reindex(columns=combined_columns)
elif isinstance(other, list):
if not other:
pass
elif not isinstance(other[0], DataFrame):
other = DataFrame(other)
if (self.columns.get_indexer(other.columns) >= 0).all():
other = other.reindex(columns=self.columns)
from pandas.core.reshape.concat import concat
if isinstance(other, (list, tuple)):
to_concat = [self, *other]
else:
to_concat = [self, other]
return concat(
to_concat,
ignore_index=ignore_index,
verify_integrity=verify_integrity,
sort=sort,
)
def join(
self, other, on=None, how="left", lsuffix="", rsuffix="", sort=False
) -> "DataFrame":
"""
Join columns of another DataFrame.
Join columns with `other` DataFrame either on index or on a key
column. Efficiently join multiple DataFrame objects by index at once by
passing a list.
Parameters
----------
other : DataFrame, Series, or list of DataFrame
Index should be similar to one of the columns in this one. If a
Series is passed, its name attribute must be set, and that will be
used as the column name in the resulting joined DataFrame.
on : str, list of str, or array-like, optional
Column or index level name(s) in the caller to join on the index
in `other`, otherwise joins index-on-index. If multiple
values given, the `other` DataFrame must have a MultiIndex. Can
pass an array as the join key if it is not already contained in
the calling DataFrame. Like an Excel VLOOKUP operation.
how : {'left', 'right', 'outer', 'inner'}, default 'left'
How to handle the operation of the two objects.
* left: use calling frame's index (or column if on is specified)
* right: use `other`'s index.
* outer: form union of calling frame's index (or column if on is
specified) with `other`'s index, and sort it.
lexicographically.
* inner: form intersection of calling frame's index (or column if
on is specified) with `other`'s index, preserving the order
of the calling's one.
lsuffix : str, default ''
Suffix to use from left frame's overlapping columns.
rsuffix : str, default ''
Suffix to use from right frame's overlapping columns.
sort : bool, default False
Order result DataFrame lexicographically by the join key. If False,
the order of the join key depends on the join type (how keyword).
Returns
-------
DataFrame
A dataframe containing columns from both the caller and `other`.
See Also
--------
DataFrame.merge : For column(s)-on-columns(s) operations.
Notes
-----
Parameters `on`, `lsuffix`, and `rsuffix` are not supported when
passing a list of `DataFrame` objects.
Support for specifying index levels as the `on` parameter was added
in version 0.23.0.
Examples
--------
>>> df = pd.DataFrame({'key': ['K0', 'K1', 'K2', 'K3', 'K4', 'K5'],
... 'A': ['A0', 'A1', 'A2', 'A3', 'A4', 'A5']})
>>> df
key A
0 K0 A0
1 K1 A1
2 K2 A2
3 K3 A3
4 K4 A4
5 K5 A5
>>> other = pd.DataFrame({'key': ['K0', 'K1', 'K2'],
... 'B': ['B0', 'B1', 'B2']})
>>> other
key B
0 K0 B0
1 K1 B1
2 K2 B2
Join DataFrames using their indexes.
>>> df.join(other, lsuffix='_caller', rsuffix='_other')
key_caller A key_other B
0 K0 A0 K0 B0
1 K1 A1 K1 B1
2 K2 A2 K2 B2
3 K3 A3 NaN NaN
4 K4 A4 NaN NaN
5 K5 A5 NaN NaN
If we want to join using the key columns, we need to set key to be
the index in both `df` and `other`. The joined DataFrame will have
key as its index.
>>> df.set_index('key').join(other.set_index('key'))
A B
key
K0 A0 B0
K1 A1 B1
K2 A2 B2
K3 A3 NaN
K4 A4 NaN
K5 A5 NaN
Another option to join using the key columns is to use the `on`
parameter. DataFrame.join always uses `other`'s index but we can use
any column in `df`. This method preserves the original DataFrame's
index in the result.
>>> df.join(other.set_index('key'), on='key')
key A B
0 K0 A0 B0
1 K1 A1 B1
2 K2 A2 B2
3 K3 A3 NaN
4 K4 A4 NaN
5 K5 A5 NaN
"""
return self._join_compat(
other, on=on, how=how, lsuffix=lsuffix, rsuffix=rsuffix, sort=sort
)
def _join_compat(
self, other, on=None, how="left", lsuffix="", rsuffix="", sort=False
):
from pandas.core.reshape.merge import merge
from pandas.core.reshape.concat import concat
if isinstance(other, Series):
if other.name is None:
raise ValueError("Other Series must have a name")
other = DataFrame({other.name: other})
if isinstance(other, DataFrame):
return merge(
self,
other,
left_on=on,
how=how,
left_index=on is None,
right_index=True,
suffixes=(lsuffix, rsuffix),
sort=sort,
)
else:
if on is not None:
raise ValueError(
"Joining multiple DataFrames only supported for joining on index"
)
frames = [self] + list(other)
can_concat = all(df.index.is_unique for df in frames)
# join indexes only using concat
if can_concat:
if how == "left":
res = concat(
frames, axis=1, join="outer", verify_integrity=True, sort=sort
)
return res.reindex(self.index, copy=False)
else:
return concat(
frames, axis=1, join=how, verify_integrity=True, sort=sort
)
joined = frames[0]
for frame in frames[1:]:
joined = merge(
joined, frame, how=how, left_index=True, right_index=True
)
return joined
@Substitution("")
@Appender(_merge_doc, indents=2)
def merge(
self,
right,
how="inner",
on=None,
left_on=None,
right_on=None,
left_index=False,
right_index=False,
sort=False,
suffixes=("_x", "_y"),
copy=True,
indicator=False,
validate=None,
) -> "DataFrame":
from pandas.core.reshape.merge import merge
return merge(
self,
right,
how=how,
on=on,
left_on=left_on,
right_on=right_on,
left_index=left_index,
right_index=right_index,
sort=sort,
suffixes=suffixes,
copy=copy,
indicator=indicator,
validate=validate,
)
def round(self, decimals=0, *args, **kwargs) -> "DataFrame":
"""
Round a DataFrame to a variable number of decimal places.
Parameters
----------
decimals : int, dict, Series
Number of decimal places to round each column to. If an int is
given, round each column to the same number of places.
Otherwise dict and Series round to variable numbers of places.
Column names should be in the keys if `decimals` is a
dict-like, or in the index if `decimals` is a Series. Any
columns not included in `decimals` will be left as is. Elements
of `decimals` which are not columns of the input will be
ignored.
*args
Additional keywords have no effect but might be accepted for
compatibility with numpy.
**kwargs
Additional keywords have no effect but might be accepted for
compatibility with numpy.
Returns
-------
DataFrame
A DataFrame with the affected columns rounded to the specified
number of decimal places.
See Also
--------
numpy.around : Round a numpy array to the given number of decimals.
Series.round : Round a Series to the given number of decimals.
Examples
--------
>>> df = pd.DataFrame([(.21, .32), (.01, .67), (.66, .03), (.21, .18)],
... columns=['dogs', 'cats'])
>>> df
dogs cats
0 0.21 0.32
1 0.01 0.67
2 0.66 0.03
3 0.21 0.18
By providing an integer each column is rounded to the same number
of decimal places
>>> df.round(1)
dogs cats
0 0.2 0.3
1 0.0 0.7
2 0.7 0.0
3 0.2 0.2
With a dict, the number of places for specific columns can be
specified with the column names as key and the number of decimal
places as value
>>> df.round({'dogs': 1, 'cats': 0})
dogs cats
0 0.2 0.0
1 0.0 1.0
2 0.7 0.0
3 0.2 0.0
Using a Series, the number of places for specific columns can be
specified with the column names as index and the number of
decimal places as value
>>> decimals = pd.Series([0, 1], index=['cats', 'dogs'])
>>> df.round(decimals)
dogs cats
0 0.2 0.0
1 0.0 1.0
2 0.7 0.0
3 0.2 0.0
"""
from pandas.core.reshape.concat import concat
def _dict_round(df, decimals):
for col, vals in df.items():
try:
yield _series_round(vals, decimals[col])
except KeyError:
yield vals
def _series_round(s, decimals):
if is_integer_dtype(s) or is_float_dtype(s):
return s.round(decimals)
return s
nv.validate_round(args, kwargs)
if isinstance(decimals, (dict, Series)):
if isinstance(decimals, Series):
if not decimals.index.is_unique:
raise ValueError("Index of decimals must be unique")
new_cols = list(_dict_round(self, decimals))
elif is_integer(decimals):
# Dispatch to Series.round
new_cols = [_series_round(v, decimals) for _, v in self.items()]
else:
raise TypeError("decimals must be an integer, a dict-like or a Series")
if len(new_cols) > 0:
return self._constructor(
concat(new_cols, axis=1), index=self.index, columns=self.columns
)
else:
return self
# ----------------------------------------------------------------------
# Statistical methods, etc.
def corr(self, method="pearson", min_periods=1) -> "DataFrame":
"""
Compute pairwise correlation of columns, excluding NA/null values.
Parameters
----------
method : {'pearson', 'kendall', 'spearman'} or callable
Method of correlation:
* pearson : standard correlation coefficient
* kendall : Kendall Tau correlation coefficient
* spearman : Spearman rank correlation
* callable: callable with input two 1d ndarrays
and returning a float. Note that the returned matrix from corr
will have 1 along the diagonals and will be symmetric
regardless of the callable's behavior.
.. versionadded:: 0.24.0
min_periods : int, optional
Minimum number of observations required per pair of columns
to have a valid result. Currently only available for Pearson
and Spearman correlation.
Returns
-------
DataFrame
Correlation matrix.
See Also
--------
DataFrame.corrwith : Compute pairwise correlation with another
DataFrame or Series.
Series.corr : Compute the correlation between two Series.
Examples
--------
>>> def histogram_intersection(a, b):
... v = np.minimum(a, b).sum().round(decimals=1)
... return v
>>> df = pd.DataFrame([(.2, .3), (.0, .6), (.6, .0), (.2, .1)],
... columns=['dogs', 'cats'])
>>> df.corr(method=histogram_intersection)
dogs cats
dogs 1.0 0.3
cats 0.3 1.0
"""
numeric_df = self._get_numeric_data()
cols = numeric_df.columns
idx = cols.copy()
mat = numeric_df.values
if method == "pearson":
correl = libalgos.nancorr(ensure_float64(mat), minp=min_periods)
elif method == "spearman":
correl = libalgos.nancorr_spearman(ensure_float64(mat), minp=min_periods)
elif method == "kendall" or callable(method):
if min_periods is None:
min_periods = 1
mat = ensure_float64(mat).T
corrf = nanops.get_corr_func(method)
K = len(cols)
correl = np.empty((K, K), dtype=float)
mask = np.isfinite(mat)
for i, ac in enumerate(mat):
for j, bc in enumerate(mat):
if i > j:
continue
valid = mask[i] & mask[j]
if valid.sum() < min_periods:
c = np.nan
elif i == j:
c = 1.0
elif not valid.all():
c = corrf(ac[valid], bc[valid])
else:
c = corrf(ac, bc)
correl[i, j] = c
correl[j, i] = c
else:
raise ValueError(
"method must be either 'pearson', "
"'spearman', 'kendall', or a callable, "
f"'{method}' was supplied"
)
return self._constructor(correl, index=idx, columns=cols)
def cov(self, min_periods=None) -> "DataFrame":
"""
Compute pairwise covariance of columns, excluding NA/null values.
Compute the pairwise covariance among the series of a DataFrame.
The returned data frame is the `covariance matrix
<https://en.wikipedia.org/wiki/Covariance_matrix>`__ of the columns
of the DataFrame.
Both NA and null values are automatically excluded from the
calculation. (See the note below about bias from missing values.)
A threshold can be set for the minimum number of
observations for each value created. Comparisons with observations
below this threshold will be returned as ``NaN``.
This method is generally used for the analysis of time series data to
understand the relationship between different measures
across time.
Parameters
----------
min_periods : int, optional
Minimum number of observations required per pair of columns
to have a valid result.
Returns
-------
DataFrame
The covariance matrix of the series of the DataFrame.
See Also
--------
Series.cov : Compute covariance with another Series.
core.window.EWM.cov: Exponential weighted sample covariance.
core.window.Expanding.cov : Expanding sample covariance.
core.window.Rolling.cov : Rolling sample covariance.
Notes
-----
Returns the covariance matrix of the DataFrame's time series.
The covariance is normalized by N-1.
For DataFrames that have Series that are missing data (assuming that
data is `missing at random
<https://en.wikipedia.org/wiki/Missing_data#Missing_at_random>`__)
the returned covariance matrix will be an unbiased estimate
of the variance and covariance between the member Series.
However, for many applications this estimate may not be acceptable
because the estimate covariance matrix is not guaranteed to be positive
semi-definite. This could lead to estimate correlations having
absolute values which are greater than one, and/or a non-invertible
covariance matrix. See `Estimation of covariance matrices
<https://en.wikipedia.org/w/index.php?title=Estimation_of_covariance_
matrices>`__ for more details.
Examples
--------
>>> df = pd.DataFrame([(1, 2), (0, 3), (2, 0), (1, 1)],
... columns=['dogs', 'cats'])
>>> df.cov()
dogs cats
dogs 0.666667 -1.000000
cats -1.000000 1.666667
>>> np.random.seed(42)
>>> df = pd.DataFrame(np.random.randn(1000, 5),
... columns=['a', 'b', 'c', 'd', 'e'])
>>> df.cov()
a b c d e
a 0.998438 -0.020161 0.059277 -0.008943 0.014144
b -0.020161 1.059352 -0.008543 -0.024738 0.009826
c 0.059277 -0.008543 1.010670 -0.001486 -0.000271
d -0.008943 -0.024738 -0.001486 0.921297 -0.013692
e 0.014144 0.009826 -0.000271 -0.013692 0.977795
**Minimum number of periods**
This method also supports an optional ``min_periods`` keyword
that specifies the required minimum number of non-NA observations for
each column pair in order to have a valid result:
>>> np.random.seed(42)
>>> df = pd.DataFrame(np.random.randn(20, 3),
... columns=['a', 'b', 'c'])
>>> df.loc[df.index[:5], 'a'] = np.nan
>>> df.loc[df.index[5:10], 'b'] = np.nan
>>> df.cov(min_periods=12)
a b c
a 0.316741 NaN -0.150812
b NaN 1.248003 0.191417
c -0.150812 0.191417 0.895202
"""
numeric_df = self._get_numeric_data()
cols = numeric_df.columns
idx = cols.copy()
mat = numeric_df.values
if notna(mat).all():
if min_periods is not None and min_periods > len(mat):
baseCov = np.empty((mat.shape[1], mat.shape[1]))
baseCov.fill(np.nan)
else:
baseCov = np.cov(mat.T)
baseCov = baseCov.reshape((len(cols), len(cols)))
else:
baseCov = libalgos.nancorr(ensure_float64(mat), cov=True, minp=min_periods)
return self._constructor(baseCov, index=idx, columns=cols)
def corrwith(self, other, axis=0, drop=False, method="pearson") -> Series:
"""
Compute pairwise correlation.
Pairwise correlation is computed between rows or columns of
DataFrame with rows or columns of Series or DataFrame. DataFrames
are first aligned along both axes before computing the
correlations.
Parameters
----------
other : DataFrame, Series
Object with which to compute correlations.
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to use. 0 or 'index' to compute column-wise, 1 or 'columns' for
row-wise.
drop : bool, default False
Drop missing indices from result.
method : {'pearson', 'kendall', 'spearman'} or callable
Method of correlation:
* pearson : standard correlation coefficient
* kendall : Kendall Tau correlation coefficient
* spearman : Spearman rank correlation
* callable: callable with input two 1d ndarrays
and returning a float.
.. versionadded:: 0.24.0
Returns
-------
Series
Pairwise correlations.
See Also
--------
DataFrame.corr : Compute pairwise correlation of columns.
"""
axis = self._get_axis_number(axis)
this = self._get_numeric_data()
if isinstance(other, Series):
return this.apply(lambda x: other.corr(x, method=method), axis=axis)
other = other._get_numeric_data()
left, right = this.align(other, join="inner", copy=False)
if axis == 1:
left = left.T
right = right.T
if method == "pearson":
# mask missing values
left = left + right * 0
right = right + left * 0
# demeaned data
ldem = left - left.mean()
rdem = right - right.mean()
num = (ldem * rdem).sum()
dom = (left.count() - 1) * left.std() * right.std()
correl = num / dom
elif method in ["kendall", "spearman"] or callable(method):
def c(x):
return nanops.nancorr(x[0], x[1], method=method)
correl = Series(
map(c, zip(left.values.T, right.values.T)), index=left.columns
)
else:
raise ValueError(
f"Invalid method {method} was passed, "
"valid methods are: 'pearson', 'kendall', "
"'spearman', or callable"
)
if not drop:
# Find non-matching labels along the given axis
# and append missing correlations (GH 22375)
raxis = 1 if axis == 0 else 0
result_index = this._get_axis(raxis).union(other._get_axis(raxis))
idx_diff = result_index.difference(correl.index)
if len(idx_diff) > 0:
correl = correl.append(Series([np.nan] * len(idx_diff), index=idx_diff))
return correl
# ----------------------------------------------------------------------
# ndarray-like stats methods
def count(self, axis=0, level=None, numeric_only=False):
"""
Count non-NA cells for each column or row.
The values `None`, `NaN`, `NaT`, and optionally `numpy.inf` (depending
on `pandas.options.mode.use_inf_as_na`) are considered NA.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
If 0 or 'index' counts are generated for each column.
If 1 or 'columns' counts are generated for each **row**.
level : int or str, optional
If the axis is a `MultiIndex` (hierarchical), count along a
particular `level`, collapsing into a `DataFrame`.
A `str` specifies the level name.
numeric_only : bool, default False
Include only `float`, `int` or `boolean` data.
Returns
-------
Series or DataFrame
For each column/row the number of non-NA/null entries.
If `level` is specified returns a `DataFrame`.
See Also
--------
Series.count: Number of non-NA elements in a Series.
DataFrame.shape: Number of DataFrame rows and columns (including NA
elements).
DataFrame.isna: Boolean same-sized DataFrame showing places of NA
elements.
Examples
--------
Constructing DataFrame from a dictionary:
>>> df = pd.DataFrame({"Person":
... ["John", "Myla", "Lewis", "John", "Myla"],
... "Age": [24., np.nan, 21., 33, 26],
... "Single": [False, True, True, True, False]})
>>> df
Person Age Single
0 John 24.0 False
1 Myla NaN True
2 Lewis 21.0 True
3 John 33.0 True
4 Myla 26.0 False
Notice the uncounted NA values:
>>> df.count()
Person 5
Age 4
Single 5
dtype: int64
Counts for each **row**:
>>> df.count(axis='columns')
0 3
1 2
2 3
3 3
4 3
dtype: int64
Counts for one level of a `MultiIndex`:
>>> df.set_index(["Person", "Single"]).count(level="Person")
Age
Person
John 2
Lewis 1
Myla 1
"""
axis = self._get_axis_number(axis)
if level is not None:
return self._count_level(level, axis=axis, numeric_only=numeric_only)
if numeric_only:
frame = self._get_numeric_data()
else:
frame = self
# GH #423
if len(frame._get_axis(axis)) == 0:
result = Series(0, index=frame._get_agg_axis(axis))
else:
if frame._is_mixed_type or frame._data.any_extension_types:
# the or any_extension_types is really only hit for single-
# column frames with an extension array
result = notna(frame).sum(axis=axis)
else:
# GH13407
series_counts = notna(frame).sum(axis=axis)
counts = series_counts.values
result = Series(counts, index=frame._get_agg_axis(axis))
return result.astype("int64")
def _count_level(self, level, axis=0, numeric_only=False):
if numeric_only:
frame = self._get_numeric_data()
else:
frame = self
count_axis = frame._get_axis(axis)
agg_axis = frame._get_agg_axis(axis)
if not isinstance(count_axis, ABCMultiIndex):
raise TypeError(
f"Can only count levels on hierarchical {self._get_axis_name(axis)}."
)
if frame._is_mixed_type:
# Since we have mixed types, calling notna(frame.values) might
# upcast everything to object
mask = notna(frame).values
else:
# But use the speedup when we have homogeneous dtypes
mask = notna(frame.values)
if axis == 1:
# We're transposing the mask rather than frame to avoid potential
# upcasts to object, which induces a ~20x slowdown
mask = mask.T
if isinstance(level, str):
level = count_axis._get_level_number(level)
level_name = count_axis._names[level]
level_index = count_axis.levels[level]._shallow_copy(name=level_name)
level_codes = ensure_int64(count_axis.codes[level])
counts = lib.count_level_2d(mask, level_codes, len(level_index), axis=0)
result = DataFrame(counts, index=level_index, columns=agg_axis)
if axis == 1:
# Undo our earlier transpose
return result.T
else:
return result
def _reduce(
self, op, name, axis=0, skipna=True, numeric_only=None, filter_type=None, **kwds
):
assert filter_type is None or filter_type == "bool", filter_type
dtype_is_dt = self.dtypes.apply(
lambda x: is_datetime64_any_dtype(x) or is_period_dtype(x)
)
if numeric_only is None and name in ["mean", "median"] and dtype_is_dt.any():
warnings.warn(
"DataFrame.mean and DataFrame.median with numeric_only=None "
"will include datetime64, datetime64tz, and PeriodDtype columns in a "
"future version.",
FutureWarning,
stacklevel=3,
)
cols = self.columns[~dtype_is_dt]
self = self[cols]
if axis is None and filter_type == "bool":
labels = None
constructor = None
else:
# TODO: Make other agg func handle axis=None properly
axis = self._get_axis_number(axis)
labels = self._get_agg_axis(axis)
constructor = self._constructor
def f(x):
return op(x, axis=axis, skipna=skipna, **kwds)
def _get_data(axis_matters):
if filter_type is None:
data = self._get_numeric_data()
elif filter_type == "bool":
if axis_matters:
# GH#25101, GH#24434
data = self._get_bool_data() if axis == 0 else self
else:
data = self._get_bool_data()
else: # pragma: no cover
msg = (
f"Generating numeric_only data with filter_type {filter_type} "
"not supported."
)
raise NotImplementedError(msg)
return data
if numeric_only is not None and axis in [0, 1]:
df = self
if numeric_only is True:
df = _get_data(axis_matters=True)
if axis == 1:
df = df.T
axis = 0
out_dtype = "bool" if filter_type == "bool" else None
def blk_func(values):
if values.ndim == 1 and not isinstance(values, np.ndarray):
# we can't pass axis=1
return op(values, axis=0, skipna=skipna, **kwds)
return op(values, axis=1, skipna=skipna, **kwds)
# After possibly _get_data and transposing, we are now in the
# simple case where we can use BlockManager._reduce
res = df._data.reduce(blk_func)
assert isinstance(res, dict)
if len(res):
assert len(res) == max(list(res.keys())) + 1, res.keys()
out = df._constructor_sliced(res, index=range(len(res)), dtype=out_dtype)
out.index = df.columns
if axis == 0 and df.dtypes.apply(needs_i8_conversion).any():
# FIXME: needs_i8_conversion check is kludge, not sure
# why it is necessary in this case and this case alone
out[:] = coerce_to_dtypes(out.values, df.dtypes)
return out
if numeric_only is None:
data = self
values = data.values
try:
result = f(values)
except TypeError:
# e.g. in nanops trying to convert strs to float
# try by-column first
if filter_type is None and axis == 0:
# this can end up with a non-reduction
# but not always. if the types are mixed
# with datelike then need to make sure a series
# we only end up here if we have not specified
# numeric_only and yet we have tried a
# column-by-column reduction, where we have mixed type.
# So let's just do what we can
from pandas.core.apply import frame_apply
opa = frame_apply(
self, func=f, result_type="expand", ignore_failures=True
)
result = opa.get_result()
if result.ndim == self.ndim:
result = result.iloc[0]
return result
# TODO: why doesnt axis matter here?
data = _get_data(axis_matters=False)
labels = data._get_agg_axis(axis)
values = data.values
with np.errstate(all="ignore"):
result = f(values)
else:
if numeric_only:
data = _get_data(axis_matters=True)
labels = data._get_agg_axis(axis)
values = data.values
else:
data = self
values = data.values
result = f(values)
if filter_type == "bool" and is_object_dtype(values) and axis is None:
# work around https://github.com/numpy/numpy/issues/10489
# TODO: can we de-duplicate parts of this with the next blocK?
result = np.bool_(result)
elif hasattr(result, "dtype") and is_object_dtype(result.dtype):
try:
if filter_type is None:
result = result.astype(np.float64)
elif filter_type == "bool" and notna(result).all():
result = result.astype(np.bool_)
except (ValueError, TypeError):
# try to coerce to the original dtypes item by item if we can
if axis == 0:
result = coerce_to_dtypes(result, data.dtypes)
if constructor is not None:
result = self._constructor_sliced(result, index=labels)
return result
def nunique(self, axis=0, dropna=True) -> Series:
"""
Count distinct observations over requested axis.
Return Series with number of distinct observations. Can ignore NaN
values.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to use. 0 or 'index' for row-wise, 1 or 'columns' for
column-wise.
dropna : bool, default True
Don't include NaN in the counts.
Returns
-------
Series
See Also
--------
Series.nunique: Method nunique for Series.
DataFrame.count: Count non-NA cells for each column or row.
Examples
--------
>>> df = pd.DataFrame({'A': [1, 2, 3], 'B': [1, 1, 1]})
>>> df.nunique()
A 3
B 1
dtype: int64
>>> df.nunique(axis=1)
0 1
1 2
2 2
dtype: int64
"""
return self.apply(Series.nunique, axis=axis, dropna=dropna)
def idxmin(self, axis=0, skipna=True) -> Series:
"""
Return index of first occurrence of minimum over requested axis.
NA/null values are excluded.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to use. 0 or 'index' for row-wise, 1 or 'columns' for column-wise.
skipna : bool, default True
Exclude NA/null values. If an entire row/column is NA, the result
will be NA.
Returns
-------
Series
Indexes of minima along the specified axis.
Raises
------
ValueError
* If the row/column is empty
See Also
--------
Series.idxmin : Return index of the minimum element.
Notes
-----
This method is the DataFrame version of ``ndarray.argmin``.
Examples
--------
Consider a dataset containing food consumption in Argentina.
>>> df = pd.DataFrame({'consumption': [10.51, 103.11, 55.48],
... 'co2_emissions': [37.2, 19.66, 1712]},
... index=['Pork', 'Wheat Products', 'Beef'])
>>> df
consumption co2_emissions
Pork 10.51 37.20
Wheat Products 103.11 19.66
Beef 55.48 1712.00
By default, it returns the index for the minimum value in each column.
>>> df.idxmin()
consumption Pork
co2_emissions Wheat Products
dtype: object
To return the index for the minimum value in each row, use ``axis="columns"``.
>>> df.idxmin(axis="columns")
Pork consumption
Wheat Products co2_emissions
Beef consumption
dtype: object
"""
axis = self._get_axis_number(axis)
indices = nanops.nanargmin(self.values, axis=axis, skipna=skipna)
index = self._get_axis(axis)
result = [index[i] if i >= 0 else np.nan for i in indices]
return Series(result, index=self._get_agg_axis(axis))
def idxmax(self, axis=0, skipna=True) -> Series:
"""
Return index of first occurrence of maximum over requested axis.
NA/null values are excluded.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to use. 0 or 'index' for row-wise, 1 or 'columns' for column-wise.
skipna : bool, default True
Exclude NA/null values. If an entire row/column is NA, the result
will be NA.
Returns
-------
Series
Indexes of maxima along the specified axis.
Raises
------
ValueError
* If the row/column is empty
See Also
--------
Series.idxmax : Return index of the maximum element.
Notes
-----
This method is the DataFrame version of ``ndarray.argmax``.
Examples
--------
Consider a dataset containing food consumption in Argentina.
>>> df = pd.DataFrame({'consumption': [10.51, 103.11, 55.48],
... 'co2_emissions': [37.2, 19.66, 1712]},
... index=['Pork', 'Wheat Products', 'Beef'])
>>> df
consumption co2_emissions
Pork 10.51 37.20
Wheat Products 103.11 19.66
Beef 55.48 1712.00
By default, it returns the index for the maximum value in each column.
>>> df.idxmax()
consumption Wheat Products
co2_emissions Beef
dtype: object
To return the index for the maximum value in each row, use ``axis="columns"``.
>>> df.idxmax(axis="columns")
Pork co2_emissions
Wheat Products consumption
Beef co2_emissions
dtype: object
"""
axis = self._get_axis_number(axis)
indices = nanops.nanargmax(self.values, axis=axis, skipna=skipna)
index = self._get_axis(axis)
result = [index[i] if i >= 0 else np.nan for i in indices]
return Series(result, index=self._get_agg_axis(axis))
def _get_agg_axis(self, axis_num):
"""
Let's be explicit about this.
"""
if axis_num == 0:
return self.columns
elif axis_num == 1:
return self.index
else:
raise ValueError(f"Axis must be 0 or 1 (got {repr(axis_num)})")
def mode(self, axis=0, numeric_only=False, dropna=True) -> "DataFrame":
"""
Get the mode(s) of each element along the selected axis.
The mode of a set of values is the value that appears most often.
It can be multiple values.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to iterate over while searching for the mode:
* 0 or 'index' : get mode of each column
* 1 or 'columns' : get mode of each row.
numeric_only : bool, default False
If True, only apply to numeric columns.
dropna : bool, default True
Don't consider counts of NaN/NaT.
.. versionadded:: 0.24.0
Returns
-------
DataFrame
The modes of each column or row.
See Also
--------
Series.mode : Return the highest frequency value in a Series.
Series.value_counts : Return the counts of values in a Series.
Examples
--------
>>> df = pd.DataFrame([('bird', 2, 2),
... ('mammal', 4, np.nan),
... ('arthropod', 8, 0),
... ('bird', 2, np.nan)],
... index=('falcon', 'horse', 'spider', 'ostrich'),
... columns=('species', 'legs', 'wings'))
>>> df
species legs wings
falcon bird 2 2.0
horse mammal 4 NaN
spider arthropod 8 0.0
ostrich bird 2 NaN
By default, missing values are not considered, and the mode of wings
are both 0 and 2. The second row of species and legs contains ``NaN``,
because they have only one mode, but the DataFrame has two rows.
>>> df.mode()
species legs wings
0 bird 2.0 0.0
1 NaN NaN 2.0
Setting ``dropna=False`` ``NaN`` values are considered and they can be
the mode (like for wings).
>>> df.mode(dropna=False)
species legs wings
0 bird 2 NaN
Setting ``numeric_only=True``, only the mode of numeric columns is
computed, and columns of other types are ignored.
>>> df.mode(numeric_only=True)
legs wings
0 2.0 0.0
1 NaN 2.0
To compute the mode over columns and not rows, use the axis parameter:
>>> df.mode(axis='columns', numeric_only=True)
0 1
falcon 2.0 NaN
horse 4.0 NaN
spider 0.0 8.0
ostrich 2.0 NaN
"""
data = self if not numeric_only else self._get_numeric_data()
def f(s):
return s.mode(dropna=dropna)
return data.apply(f, axis=axis)
def quantile(self, q=0.5, axis=0, numeric_only=True, interpolation="linear"):
"""
Return values at the given quantile over requested axis.
Parameters
----------
q : float or array-like, default 0.5 (50% quantile)
Value between 0 <= q <= 1, the quantile(s) to compute.
axis : {0, 1, 'index', 'columns'} (default 0)
Equals 0 or 'index' for row-wise, 1 or 'columns' for column-wise.
numeric_only : bool, default True
If False, the quantile of datetime and timedelta data will be
computed as well.
interpolation : {'linear', 'lower', 'higher', 'midpoint', 'nearest'}
This optional parameter specifies the interpolation method to use,
when the desired quantile lies between two data points `i` and `j`:
* linear: `i + (j - i) * fraction`, where `fraction` is the
fractional part of the index surrounded by `i` and `j`.
* lower: `i`.
* higher: `j`.
* nearest: `i` or `j` whichever is nearest.
* midpoint: (`i` + `j`) / 2.
Returns
-------
Series or DataFrame
If ``q`` is an array, a DataFrame will be returned where the
index is ``q``, the columns are the columns of self, and the
values are the quantiles.
If ``q`` is a float, a Series will be returned where the
index is the columns of self and the values are the quantiles.
See Also
--------
core.window.Rolling.quantile: Rolling quantile.
numpy.percentile: Numpy function to compute the percentile.
Examples
--------
>>> df = pd.DataFrame(np.array([[1, 1], [2, 10], [3, 100], [4, 100]]),
... columns=['a', 'b'])
>>> df.quantile(.1)
a 1.3
b 3.7
Name: 0.1, dtype: float64
>>> df.quantile([.1, .5])
a b
0.1 1.3 3.7
0.5 2.5 55.0
Specifying `numeric_only=False` will also compute the quantile of
datetime and timedelta data.
>>> df = pd.DataFrame({'A': [1, 2],
... 'B': [pd.Timestamp('2010'),
... pd.Timestamp('2011')],
... 'C': [pd.Timedelta('1 days'),
... pd.Timedelta('2 days')]})
>>> df.quantile(0.5, numeric_only=False)
A 1.5
B 2010-07-02 12:00:00
C 1 days 12:00:00
Name: 0.5, dtype: object
"""
validate_percentile(q)
data = self._get_numeric_data() if numeric_only else self
axis = self._get_axis_number(axis)
is_transposed = axis == 1
if is_transposed:
data = data.T
if len(data.columns) == 0:
# GH#23925 _get_numeric_data may have dropped all columns
cols = Index([], name=self.columns.name)
if is_list_like(q):
return self._constructor([], index=q, columns=cols)
return self._constructor_sliced([], index=cols, name=q, dtype=np.float64)
result = data._data.quantile(
qs=q, axis=1, interpolation=interpolation, transposed=is_transposed
)
if result.ndim == 2:
result = self._constructor(result)
else:
result = self._constructor_sliced(result, name=q)
if is_transposed:
result = result.T
return result
def to_timestamp(
self, freq=None, how: str = "start", axis: Axis = 0, copy: bool = True
) -> "DataFrame":
"""
Cast to DatetimeIndex of timestamps, at *beginning* of period.
Parameters
----------
freq : str, default frequency of PeriodIndex
Desired frequency.
how : {'s', 'e', 'start', 'end'}
Convention for converting period to timestamp; start of period
vs. end.
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to convert (the index by default).
copy : bool, default True
If False then underlying input data is not copied.
Returns
-------
DataFrame with DatetimeIndex
"""
new_obj = self.copy(deep=copy)
axis_name = self._get_axis_name(axis)
old_ax = getattr(self, axis_name)
new_ax = old_ax.to_timestamp(freq=freq, how=how)
setattr(new_obj, axis_name, new_ax)
return new_obj
def to_period(self, freq=None, axis: Axis = 0, copy: bool = True) -> "DataFrame":
"""
Convert DataFrame from DatetimeIndex to PeriodIndex.
Convert DataFrame from DatetimeIndex to PeriodIndex with desired
frequency (inferred from index if not passed).
Parameters
----------
freq : str, default
Frequency of the PeriodIndex.
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to convert (the index by default).
copy : bool, default True
If False then underlying input data is not copied.
Returns
-------
DataFrame with PeriodIndex
"""
new_obj = self.copy(deep=copy)
axis_name = self._get_axis_name(axis)
old_ax = getattr(self, axis_name)
new_ax = old_ax.to_period(freq=freq)
setattr(new_obj, axis_name, new_ax)
return new_obj
def isin(self, values) -> "DataFrame":
"""
Whether each element in the DataFrame is contained in values.
Parameters
----------
values : iterable, Series, DataFrame or dict
The result will only be true at a location if all the
labels match. If `values` is a Series, that's the index. If
`values` is a dict, the keys must be the column names,
which must match. If `values` is a DataFrame,
then both the index and column labels must match.
Returns
-------
DataFrame
DataFrame of booleans showing whether each element in the DataFrame
is contained in values.
See Also
--------
DataFrame.eq: Equality test for DataFrame.
Series.isin: Equivalent method on Series.
Series.str.contains: Test if pattern or regex is contained within a
string of a Series or Index.
Examples
--------
>>> df = pd.DataFrame({'num_legs': [2, 4], 'num_wings': [2, 0]},
... index=['falcon', 'dog'])
>>> df
num_legs num_wings
falcon 2 2
dog 4 0
When ``values`` is a list check whether every value in the DataFrame
is present in the list (which animals have 0 or 2 legs or wings)
>>> df.isin([0, 2])
num_legs num_wings
falcon True True
dog False True
When ``values`` is a dict, we can pass values to check for each
column separately:
>>> df.isin({'num_wings': [0, 3]})
num_legs num_wings
falcon False False
dog False True
When ``values`` is a Series or DataFrame the index and column must
match. Note that 'falcon' does not match based on the number of legs
in df2.
>>> other = pd.DataFrame({'num_legs': [8, 2], 'num_wings': [0, 2]},
... index=['spider', 'falcon'])
>>> df.isin(other)
num_legs num_wings
falcon True True
dog False False
"""
if isinstance(values, dict):
from pandas.core.reshape.concat import concat
values = collections.defaultdict(list, values)
return concat(
(
self.iloc[:, [i]].isin(values[col])
for i, col in enumerate(self.columns)
),
axis=1,
)
elif isinstance(values, Series):
if not values.index.is_unique:
raise ValueError("cannot compute isin with a duplicate axis.")
return self.eq(values.reindex_like(self), axis="index")
elif isinstance(values, DataFrame):
if not (values.columns.is_unique and values.index.is_unique):
raise ValueError("cannot compute isin with a duplicate axis.")
return self.eq(values.reindex_like(self))
else:
if not is_list_like(values):
raise TypeError(
"only list-like or dict-like objects are allowed "
"to be passed to DataFrame.isin(), "
f"you passed a '{type(values).__name__}'"
)
return DataFrame(
algorithms.isin(self.values.ravel(), values).reshape(self.shape),
self.index,
self.columns,
)
# ----------------------------------------------------------------------
# Add index and columns
_AXIS_ORDERS = ["index", "columns"]
_AXIS_NUMBERS = {"index": 0, "columns": 1}
_AXIS_NAMES = {0: "index", 1: "columns"}
_AXIS_REVERSED = True
_AXIS_LEN = len(_AXIS_ORDERS)
_info_axis_number = 1
_info_axis_name = "columns"
index: "Index" = properties.AxisProperty(
axis=1, doc="The index (row labels) of the DataFrame."
)
columns: "Index" = properties.AxisProperty(
axis=0, doc="The column labels of the DataFrame."
)
# ----------------------------------------------------------------------
# Add plotting methods to DataFrame
plot = CachedAccessor("plot", pandas.plotting.PlotAccessor)
hist = pandas.plotting.hist_frame
boxplot = pandas.plotting.boxplot_frame
sparse = CachedAccessor("sparse", SparseFrameAccessor)
DataFrame._add_numeric_operations()
DataFrame._add_series_or_dataframe_operations()
ops.add_flex_arithmetic_methods(DataFrame)
ops.add_special_arithmetic_methods(DataFrame)
def _from_nested_dict(data):
# TODO: this should be seriously cythonized
new_data = collections.defaultdict(dict)
for index, s in data.items():
for col, v in s.items():
new_data[col][index] = v
return new_data
"""
DataFrame
---------
An efficient 2D container for potentially mixed-type time series or other
labeled data series.
Similar to its R counterpart, data.frame, except providing automatic data
alignment and a host of useful data manipulation methods having to do with the
labeling information
"""
import collections
from collections import abc
import datetime
from io import StringIO
import itertools
from textwrap import dedent
from typing import (
IO,
TYPE_CHECKING,
Any,
Dict,
FrozenSet,
Hashable,
Iterable,
List,
Optional,
Sequence,
Set,
Tuple,
Type,
Union,
cast,
)
import warnings
import numpy as np
import numpy.ma as ma
from pandas._config import get_option
from pandas._libs import algos as libalgos, lib, properties
from pandas._typing import Axes, Axis, Dtype, FilePathOrBuffer, Label, Level, Renamer
from pandas.compat import PY37
from pandas.compat._optional import import_optional_dependency
from pandas.compat.numpy import function as nv
from pandas.util._decorators import (
Appender,
Substitution,
deprecate_kwarg,
doc,
rewrite_axis_style_signature,
)
from pandas.util._validators import (
validate_axis_style_args,
validate_bool_kwarg,
validate_percentile,
)
from pandas.core.dtypes.cast import (
cast_scalar_to_array,
coerce_to_dtypes,
find_common_type,
infer_dtype_from_scalar,
invalidate_string_dtypes,
maybe_cast_to_datetime,
maybe_convert_platform,
maybe_downcast_to_dtype,
maybe_infer_to_datetimelike,
maybe_upcast,
maybe_upcast_putmask,
validate_numeric_casting,
)
from pandas.core.dtypes.common import (
ensure_float64,
ensure_int64,
ensure_platform_int,
infer_dtype_from_object,
is_bool_dtype,
is_datetime64_any_dtype,
is_dict_like,
is_dtype_equal,
is_extension_array_dtype,
is_float_dtype,
is_hashable,
is_integer,
is_integer_dtype,
is_iterator,
is_list_like,
is_named_tuple,
is_object_dtype,
is_period_dtype,
is_scalar,
is_sequence,
needs_i8_conversion,
)
from pandas.core.dtypes.generic import (
ABCDataFrame,
ABCIndexClass,
ABCMultiIndex,
ABCSeries,
)
from pandas.core.dtypes.missing import isna, notna
from pandas.core import algorithms, common as com, nanops, ops
from pandas.core.accessor import CachedAccessor
from pandas.core.arrays import Categorical, ExtensionArray
from pandas.core.arrays.datetimelike import DatetimeLikeArrayMixin as DatetimeLikeArray
from pandas.core.arrays.sparse import SparseFrameAccessor
from pandas.core.generic import NDFrame, _shared_docs
from pandas.core.indexes import base as ibase
from pandas.core.indexes.api import Index, ensure_index, ensure_index_from_sequences
from pandas.core.indexes.datetimes import DatetimeIndex
from pandas.core.indexes.multi import MultiIndex, maybe_droplevels
from pandas.core.indexes.period import PeriodIndex
from pandas.core.indexing import check_bool_indexer, convert_to_index_sliceable
from pandas.core.internals import BlockManager
from pandas.core.internals.construction import (
arrays_to_mgr,
get_names_from_index,
init_dict,
init_ndarray,
masked_rec_array_to_mgr,
reorder_arrays,
sanitize_index,
to_arrays,
)
from pandas.core.ops.missing import dispatch_fill_zeros
from pandas.core.series import Series
from pandas.io.common import get_filepath_or_buffer
from pandas.io.formats import console, format as fmt
from pandas.io.formats.info import info
import pandas.plotting
if TYPE_CHECKING:
from pandas.core.groupby.generic import DataFrameGroupBy
from pandas.io.formats.style import Styler
# ---------------------------------------------------------------------
# Docstring templates
_shared_doc_kwargs = dict(
axes="index, columns",
klass="DataFrame",
axes_single_arg="{0 or 'index', 1 or 'columns'}",
axis="""axis : {0 or 'index', 1 or 'columns'}, default 0
If 0 or 'index': apply function to each column.
If 1 or 'columns': apply function to each row.""",
optional_by="""
by : str or list of str
Name or list of names to sort by.
- if `axis` is 0 or `'index'` then `by` may contain index
levels and/or column labels.
- if `axis` is 1 or `'columns'` then `by` may contain column
levels and/or index labels.
.. versionchanged:: 0.23.0
Allow specifying index or column level names.""",
versionadded_to_excel="",
optional_labels="""labels : array-like, optional
New labels / index to conform the axis specified by 'axis' to.""",
optional_axis="""axis : int or str, optional
Axis to target. Can be either the axis name ('index', 'columns')
or number (0, 1).""",
)
_numeric_only_doc = """numeric_only : boolean, default None
Include only float, int, boolean data. If None, will attempt to use
everything, then use only numeric data
"""
_merge_doc = """
Merge DataFrame or named Series objects with a database-style join.
The join is done on columns or indexes. If joining columns on
columns, the DataFrame indexes *will be ignored*. Otherwise if joining indexes
on indexes or indexes on a column or columns, the index will be passed on.
Parameters
----------%s
right : DataFrame or named Series
Object to merge with.
how : {'left', 'right', 'outer', 'inner'}, default 'inner'
Type of merge to be performed.
* left: use only keys from left frame, similar to a SQL left outer join;
preserve key order.
* right: use only keys from right frame, similar to a SQL right outer join;
preserve key order.
* outer: use union of keys from both frames, similar to a SQL full outer
join; sort keys lexicographically.
* inner: use intersection of keys from both frames, similar to a SQL inner
join; preserve the order of the left keys.
on : label or list
Column or index level names to join on. These must be found in both
DataFrames. If `on` is None and not merging on indexes then this defaults
to the intersection of the columns in both DataFrames.
left_on : label or list, or array-like
Column or index level names to join on in the left DataFrame. Can also
be an array or list of arrays of the length of the left DataFrame.
These arrays are treated as if they are columns.
right_on : label or list, or array-like
Column or index level names to join on in the right DataFrame. Can also
be an array or list of arrays of the length of the right DataFrame.
These arrays are treated as if they are columns.
left_index : bool, default False
Use the index from the left DataFrame as the join key(s). If it is a
MultiIndex, the number of keys in the other DataFrame (either the index
or a number of columns) must match the number of levels.
right_index : bool, default False
Use the index from the right DataFrame as the join key. Same caveats as
left_index.
sort : bool, default False
Sort the join keys lexicographically in the result DataFrame. If False,
the order of the join keys depends on the join type (how keyword).
suffixes : tuple of (str, str), default ('_x', '_y')
Suffix to apply to overlapping column names in the left and right
side, respectively. To raise an exception on overlapping columns use
(False, False).
copy : bool, default True
If False, avoid copy if possible.
indicator : bool or str, default False
If True, adds a column to output DataFrame called "_merge" with
information on the source of each row.
If string, column with information on source of each row will be added to
output DataFrame, and column will be named value of string.
Information column is Categorical-type and takes on a value of "left_only"
for observations whose merge key only appears in 'left' DataFrame,
"right_only" for observations whose merge key only appears in 'right'
DataFrame, and "both" if the observation's merge key is found in both.
validate : str, optional
If specified, checks if merge is of specified type.
* "one_to_one" or "1:1": check if merge keys are unique in both
left and right datasets.
* "one_to_many" or "1:m": check if merge keys are unique in left
dataset.
* "many_to_one" or "m:1": check if merge keys are unique in right
dataset.
* "many_to_many" or "m:m": allowed, but does not result in checks.
.. versionadded:: 0.21.0
Returns
-------
DataFrame
A DataFrame of the two merged objects.
See Also
--------
merge_ordered : Merge with optional filling/interpolation.
merge_asof : Merge on nearest keys.
DataFrame.join : Similar method using indices.
Notes
-----
Support for specifying index levels as the `on`, `left_on`, and
`right_on` parameters was added in version 0.23.0
Support for merging named Series objects was added in version 0.24.0
Examples
--------
>>> df1 = pd.DataFrame({'lkey': ['foo', 'bar', 'baz', 'foo'],
... 'value': [1, 2, 3, 5]})
>>> df2 = pd.DataFrame({'rkey': ['foo', 'bar', 'baz', 'foo'],
... 'value': [5, 6, 7, 8]})
>>> df1
lkey value
0 foo 1
1 bar 2
2 baz 3
3 foo 5
>>> df2
rkey value
0 foo 5
1 bar 6
2 baz 7
3 foo 8
Merge df1 and df2 on the lkey and rkey columns. The value columns have
the default suffixes, _x and _y, appended.
>>> df1.merge(df2, left_on='lkey', right_on='rkey')
lkey value_x rkey value_y
0 foo 1 foo 5
1 foo 1 foo 8
2 foo 5 foo 5
3 foo 5 foo 8
4 bar 2 bar 6
5 baz 3 baz 7
Merge DataFrames df1 and df2 with specified left and right suffixes
appended to any overlapping columns.
>>> df1.merge(df2, left_on='lkey', right_on='rkey',
... suffixes=('_left', '_right'))
lkey value_left rkey value_right
0 foo 1 foo 5
1 foo 1 foo 8
2 foo 5 foo 5
3 foo 5 foo 8
4 bar 2 bar 6
5 baz 3 baz 7
Merge DataFrames df1 and df2, but raise an exception if the DataFrames have
any overlapping columns.
>>> df1.merge(df2, left_on='lkey', right_on='rkey', suffixes=(False, False))
Traceback (most recent call last):
...
ValueError: columns overlap but no suffix specified:
Index(['value'], dtype='object')
"""
# -----------------------------------------------------------------------
# DataFrame class
class DataFrame(NDFrame):
"""
Two-dimensional, size-mutable, potentially heterogeneous tabular data.
Data structure also contains labeled axes (rows and columns).
Arithmetic operations align on both row and column labels. Can be
thought of as a dict-like container for Series objects. The primary
pandas data structure.
Parameters
----------
data : ndarray (structured or homogeneous), Iterable, dict, or DataFrame
Dict can contain Series, arrays, constants, or list-like objects.
.. versionchanged:: 0.23.0
If data is a dict, column order follows insertion-order for
Python 3.6 and later.
.. versionchanged:: 0.25.0
If data is a list of dicts, column order follows insertion-order
for Python 3.6 and later.
index : Index or array-like
Index to use for resulting frame. Will default to RangeIndex if
no indexing information part of input data and no index provided.
columns : Index or array-like
Column labels to use for resulting frame. Will default to
RangeIndex (0, 1, 2, ..., n) if no column labels are provided.
dtype : dtype, default None
Data type to force. Only a single dtype is allowed. If None, infer.
copy : bool, default False
Copy data from inputs. Only affects DataFrame / 2d ndarray input.
See Also
--------
DataFrame.from_records : Constructor from tuples, also record arrays.
DataFrame.from_dict : From dicts of Series, arrays, or dicts.
read_csv : Read a comma-separated values (csv) file into DataFrame.
read_table : Read general delimited file into DataFrame.
read_clipboard : Read text from clipboard into DataFrame.
Examples
--------
Constructing DataFrame from a dictionary.
>>> d = {'col1': [1, 2], 'col2': [3, 4]}
>>> df = pd.DataFrame(data=d)
>>> df
col1 col2
0 1 3
1 2 4
Notice that the inferred dtype is int64.
>>> df.dtypes
col1 int64
col2 int64
dtype: object
To enforce a single dtype:
>>> df = pd.DataFrame(data=d, dtype=np.int8)
>>> df.dtypes
col1 int8
col2 int8
dtype: object
Constructing DataFrame from numpy ndarray:
>>> df2 = pd.DataFrame(np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]]),
... columns=['a', 'b', 'c'])
>>> df2
a b c
0 1 2 3
1 4 5 6
2 7 8 9
"""
_internal_names_set = {"columns", "index"} | NDFrame._internal_names_set
_typ = "dataframe"
@property
def _constructor(self) -> Type["DataFrame"]:
return DataFrame
_constructor_sliced: Type[Series] = Series
_deprecations: FrozenSet[str] = NDFrame._deprecations | frozenset([])
_accessors: Set[str] = {"sparse"}
@property
def _constructor_expanddim(self):
raise NotImplementedError("Not supported for DataFrames!")
# ----------------------------------------------------------------------
# Constructors
def __init__(
self,
data=None,
index: Optional[Axes] = None,
columns: Optional[Axes] = None,
dtype: Optional[Dtype] = None,
copy: bool = False,
):
if data is None:
data = {}
if dtype is not None:
dtype = self._validate_dtype(dtype)
if isinstance(data, DataFrame):
data = data._data
if isinstance(data, BlockManager):
mgr = self._init_mgr(
data, axes=dict(index=index, columns=columns), dtype=dtype, copy=copy
)
elif isinstance(data, dict):
mgr = init_dict(data, index, columns, dtype=dtype)
elif isinstance(data, ma.MaskedArray):
import numpy.ma.mrecords as mrecords
# masked recarray
if isinstance(data, mrecords.MaskedRecords):
mgr = masked_rec_array_to_mgr(data, index, columns, dtype, copy)
# a masked array
else:
mask = ma.getmaskarray(data)
if mask.any():
data, fill_value = maybe_upcast(data, copy=True)
data.soften_mask() # set hardmask False if it was True
data[mask] = fill_value
else:
data = data.copy()
mgr = init_ndarray(data, index, columns, dtype=dtype, copy=copy)
elif isinstance(data, (np.ndarray, Series, Index)):
if data.dtype.names:
data_columns = list(data.dtype.names)
data = {k: data[k] for k in data_columns}
if columns is None:
columns = data_columns
mgr = init_dict(data, index, columns, dtype=dtype)
elif getattr(data, "name", None) is not None:
mgr = init_dict({data.name: data}, index, columns, dtype=dtype)
else:
mgr = init_ndarray(data, index, columns, dtype=dtype, copy=copy)
# For data is list-like, or Iterable (will consume into list)
elif isinstance(data, abc.Iterable) and not isinstance(data, (str, bytes)):
if not isinstance(data, (abc.Sequence, ExtensionArray)):
data = list(data)
if len(data) > 0:
if is_list_like(data[0]) and getattr(data[0], "ndim", 1) == 1:
if is_named_tuple(data[0]) and columns is None:
columns = data[0]._fields
arrays, columns = to_arrays(data, columns, dtype=dtype)
columns = ensure_index(columns)
# set the index
if index is None:
if isinstance(data[0], Series):
index = get_names_from_index(data)
elif isinstance(data[0], Categorical):
index = ibase.default_index(len(data[0]))
else:
index = ibase.default_index(len(data))
mgr = arrays_to_mgr(arrays, columns, index, columns, dtype=dtype)
else:
mgr = init_ndarray(data, index, columns, dtype=dtype, copy=copy)
else:
mgr = init_dict({}, index, columns, dtype=dtype)
else:
try:
arr = np.array(data, dtype=dtype, copy=copy)
except (ValueError, TypeError) as err:
exc = TypeError(
"DataFrame constructor called with "
f"incompatible data and dtype: {err}"
)
raise exc from err
if arr.ndim == 0 and index is not None and columns is not None:
values = cast_scalar_to_array(
(len(index), len(columns)), data, dtype=dtype
)
mgr = init_ndarray(
values, index, columns, dtype=values.dtype, copy=False
)
else:
raise ValueError("DataFrame constructor not properly called!")
NDFrame.__init__(self, mgr)
# ----------------------------------------------------------------------
@property
def axes(self) -> List[Index]:
"""
Return a list representing the axes of the DataFrame.
It has the row axis labels and column axis labels as the only members.
They are returned in that order.
Examples
--------
>>> df = pd.DataFrame({'col1': [1, 2], 'col2': [3, 4]})
>>> df.axes
[RangeIndex(start=0, stop=2, step=1), Index(['col1', 'col2'],
dtype='object')]
"""
return [self.index, self.columns]
@property
def shape(self) -> Tuple[int, int]:
"""
Return a tuple representing the dimensionality of the DataFrame.
See Also
--------
ndarray.shape
Examples
--------
>>> df = pd.DataFrame({'col1': [1, 2], 'col2': [3, 4]})
>>> df.shape
(2, 2)
>>> df = pd.DataFrame({'col1': [1, 2], 'col2': [3, 4],
... 'col3': [5, 6]})
>>> df.shape
(2, 3)
"""
return len(self.index), len(self.columns)
@property
def _is_homogeneous_type(self) -> bool:
"""
Whether all the columns in a DataFrame have the same type.
Returns
-------
bool
See Also
--------
Index._is_homogeneous_type : Whether the object has a single
dtype.
MultiIndex._is_homogeneous_type : Whether all the levels of a
MultiIndex have the same dtype.
Examples
--------
>>> DataFrame({"A": [1, 2], "B": [3, 4]})._is_homogeneous_type
True
>>> DataFrame({"A": [1, 2], "B": [3.0, 4.0]})._is_homogeneous_type
False
Items with the same type but different sizes are considered
different types.
>>> DataFrame({
... "A": np.array([1, 2], dtype=np.int32),
... "B": np.array([1, 2], dtype=np.int64)})._is_homogeneous_type
False
"""
if self._data.any_extension_types:
return len({block.dtype for block in self._data.blocks}) == 1
else:
return not self._data.is_mixed_type
# ----------------------------------------------------------------------
# Rendering Methods
def _repr_fits_vertical_(self) -> bool:
"""
Check length against max_rows.
"""
max_rows = get_option("display.max_rows")
return len(self) <= max_rows
def _repr_fits_horizontal_(self, ignore_width: bool = False) -> bool:
"""
Check if full repr fits in horizontal boundaries imposed by the display
options width and max_columns.
In case of non-interactive session, no boundaries apply.
`ignore_width` is here so ipnb+HTML output can behave the way
users expect. display.max_columns remains in effect.
GH3541, GH3573
"""
width, height = console.get_console_size()
max_columns = get_option("display.max_columns")
nb_columns = len(self.columns)
# exceed max columns
if (max_columns and nb_columns > max_columns) or (
(not ignore_width) and width and nb_columns > (width // 2)
):
return False
# used by repr_html under IPython notebook or scripts ignore terminal
# dims
if ignore_width or not console.in_interactive_session():
return True
if get_option("display.width") is not None or console.in_ipython_frontend():
# check at least the column row for excessive width
max_rows = 1
else:
max_rows = get_option("display.max_rows")
# when auto-detecting, so width=None and not in ipython front end
# check whether repr fits horizontal by actually checking
# the width of the rendered repr
buf = StringIO()
# only care about the stuff we'll actually print out
# and to_string on entire frame may be expensive
d = self
if not (max_rows is None): # unlimited rows
# min of two, where one may be None
d = d.iloc[: min(max_rows, len(d))]
else:
return True
d.to_string(buf=buf)
value = buf.getvalue()
repr_width = max(len(l) for l in value.split("\n"))
return repr_width < width
def _info_repr(self) -> bool:
"""
True if the repr should show the info view.
"""
info_repr_option = get_option("display.large_repr") == "info"
return info_repr_option and not (
self._repr_fits_horizontal_() and self._repr_fits_vertical_()
)
def __repr__(self) -> str:
"""
Return a string representation for a particular DataFrame.
"""
buf = StringIO("")
if self._info_repr():
self.info(buf=buf)
return buf.getvalue()
max_rows = get_option("display.max_rows")
min_rows = get_option("display.min_rows")
max_cols = get_option("display.max_columns")
max_colwidth = get_option("display.max_colwidth")
show_dimensions = get_option("display.show_dimensions")
if get_option("display.expand_frame_repr"):
width, _ = console.get_console_size()
else:
width = None
self.to_string(
buf=buf,
max_rows=max_rows,
min_rows=min_rows,
max_cols=max_cols,
line_width=width,
max_colwidth=max_colwidth,
show_dimensions=show_dimensions,
)
return buf.getvalue()
def _repr_html_(self) -> Optional[str]:
"""
Return a html representation for a particular DataFrame.
Mainly for IPython notebook.
"""
if self._info_repr():
buf = StringIO("")
self.info(buf=buf)
# need to escape the <class>, should be the first line.
val = buf.getvalue().replace("<", r"<", 1)
val = val.replace(">", r">", 1)
return "<pre>" + val + "</pre>"
if get_option("display.notebook_repr_html"):
max_rows = get_option("display.max_rows")
min_rows = get_option("display.min_rows")
max_cols = get_option("display.max_columns")
show_dimensions = get_option("display.show_dimensions")
formatter = fmt.DataFrameFormatter(
self,
columns=None,
col_space=None,
na_rep="NaN",
formatters=None,
float_format=None,
sparsify=None,
justify=None,
index_names=True,
header=True,
index=True,
bold_rows=True,
escape=True,
max_rows=max_rows,
min_rows=min_rows,
max_cols=max_cols,
show_dimensions=show_dimensions,
decimal=".",
table_id=None,
render_links=False,
)
return formatter.to_html(notebook=True)
else:
return None
@Substitution(
header_type="bool or sequence",
header="Write out the column names. If a list of strings "
"is given, it is assumed to be aliases for the "
"column names",
col_space_type="int",
col_space="The minimum width of each column",
)
@Substitution(shared_params=fmt.common_docstring, returns=fmt.return_docstring)
def to_string(
self,
buf: Optional[FilePathOrBuffer[str]] = None,
columns: Optional[Sequence[str]] = None,
col_space: Optional[int] = None,
header: Union[bool, Sequence[str]] = True,
index: bool = True,
na_rep: str = "NaN",
formatters: Optional[fmt.FormattersType] = None,
float_format: Optional[fmt.FloatFormatType] = None,
sparsify: Optional[bool] = None,
index_names: bool = True,
justify: Optional[str] = None,
max_rows: Optional[int] = None,
min_rows: Optional[int] = None,
max_cols: Optional[int] = None,
show_dimensions: bool = False,
decimal: str = ".",
line_width: Optional[int] = None,
max_colwidth: Optional[int] = None,
encoding: Optional[str] = None,
) -> Optional[str]:
"""
Render a DataFrame to a console-friendly tabular output.
%(shared_params)s
line_width : int, optional
Width to wrap a line in characters.
max_colwidth : int, optional
Max width to truncate each column in characters. By default, no limit.
.. versionadded:: 1.0.0
encoding : str, default "utf-8"
Set character encoding.
.. versionadded:: 1.0
%(returns)s
See Also
--------
to_html : Convert DataFrame to HTML.
Examples
--------
>>> d = {'col1': [1, 2, 3], 'col2': [4, 5, 6]}
>>> df = pd.DataFrame(d)
>>> print(df.to_string())
col1 col2
0 1 4
1 2 5
2 3 6
"""
from pandas import option_context
with option_context("display.max_colwidth", max_colwidth):
formatter = fmt.DataFrameFormatter(
self,
columns=columns,
col_space=col_space,
na_rep=na_rep,
formatters=formatters,
float_format=float_format,
sparsify=sparsify,
justify=justify,
index_names=index_names,
header=header,
index=index,
min_rows=min_rows,
max_rows=max_rows,
max_cols=max_cols,
show_dimensions=show_dimensions,
decimal=decimal,
line_width=line_width,
)
return formatter.to_string(buf=buf, encoding=encoding)
# ----------------------------------------------------------------------
@property
def style(self) -> "Styler":
"""
Returns a Styler object.
Contains methods for building a styled HTML representation of the DataFrame.
See Also
--------
io.formats.style.Styler
"""
from pandas.io.formats.style import Styler
return Styler(self)
_shared_docs[
"items"
] = r"""
Iterate over (column name, Series) pairs.
Iterates over the DataFrame columns, returning a tuple with
the column name and the content as a Series.
Yields
------
label : object
The column names for the DataFrame being iterated over.
content : Series
The column entries belonging to each label, as a Series.
See Also
--------
DataFrame.iterrows : Iterate over DataFrame rows as
(index, Series) pairs.
DataFrame.itertuples : Iterate over DataFrame rows as namedtuples
of the values.
Examples
--------
>>> df = pd.DataFrame({'species': ['bear', 'bear', 'marsupial'],
... 'population': [1864, 22000, 80000]},
... index=['panda', 'polar', 'koala'])
>>> df
species population
panda bear 1864
polar bear 22000
koala marsupial 80000
>>> for label, content in df.items():
... print(f'label: {label}')
... print(f'content: {content}', sep='\n')
...
label: species
content:
panda bear
polar bear
koala marsupial
Name: species, dtype: object
label: population
content:
panda 1864
polar 22000
koala 80000
Name: population, dtype: int64
"""
@Appender(_shared_docs["items"])
def items(self) -> Iterable[Tuple[Label, Series]]:
if self.columns.is_unique and hasattr(self, "_item_cache"):
for k in self.columns:
yield k, self._get_item_cache(k)
else:
for i, k in enumerate(self.columns):
yield k, self._ixs(i, axis=1)
@Appender(_shared_docs["items"])
def iteritems(self) -> Iterable[Tuple[Label, Series]]:
yield from self.items()
def iterrows(self) -> Iterable[Tuple[Label, Series]]:
"""
Iterate over DataFrame rows as (index, Series) pairs.
Yields
------
index : label or tuple of label
The index of the row. A tuple for a `MultiIndex`.
data : Series
The data of the row as a Series.
it : generator
A generator that iterates over the rows of the frame.
See Also
--------
DataFrame.itertuples : Iterate over DataFrame rows as namedtuples of the values.
DataFrame.items : Iterate over (column name, Series) pairs.
Notes
-----
1. Because ``iterrows`` returns a Series for each row,
it does **not** preserve dtypes across the rows (dtypes are
preserved across columns for DataFrames). For example,
>>> df = pd.DataFrame([[1, 1.5]], columns=['int', 'float'])
>>> row = next(df.iterrows())[1]
>>> row
int 1.0
float 1.5
Name: 0, dtype: float64
>>> print(row['int'].dtype)
float64
>>> print(df['int'].dtype)
int64
To preserve dtypes while iterating over the rows, it is better
to use :meth:`itertuples` which returns namedtuples of the values
and which is generally faster than ``iterrows``.
2. You should **never modify** something you are iterating over.
This is not guaranteed to work in all cases. Depending on the
data types, the iterator returns a copy and not a view, and writing
to it will have no effect.
"""
columns = self.columns
klass = self._constructor_sliced
for k, v in zip(self.index, self.values):
s = klass(v, index=columns, name=k)
yield k, s
def itertuples(self, index=True, name="Pandas"):
"""
Iterate over DataFrame rows as namedtuples.
Parameters
----------
index : bool, default True
If True, return the index as the first element of the tuple.
name : str or None, default "Pandas"
The name of the returned namedtuples or None to return regular
tuples.
Returns
-------
iterator
An object to iterate over namedtuples for each row in the
DataFrame with the first field possibly being the index and
following fields being the column values.
See Also
--------
DataFrame.iterrows : Iterate over DataFrame rows as (index, Series)
pairs.
DataFrame.items : Iterate over (column name, Series) pairs.
Notes
-----
The column names will be renamed to positional names if they are
invalid Python identifiers, repeated, or start with an underscore.
On python versions < 3.7 regular tuples are returned for DataFrames
with a large number of columns (>254).
Examples
--------
>>> df = pd.DataFrame({'num_legs': [4, 2], 'num_wings': [0, 2]},
... index=['dog', 'hawk'])
>>> df
num_legs num_wings
dog 4 0
hawk 2 2
>>> for row in df.itertuples():
... print(row)
...
Pandas(Index='dog', num_legs=4, num_wings=0)
Pandas(Index='hawk', num_legs=2, num_wings=2)
By setting the `index` parameter to False we can remove the index
as the first element of the tuple:
>>> for row in df.itertuples(index=False):
... print(row)
...
Pandas(num_legs=4, num_wings=0)
Pandas(num_legs=2, num_wings=2)
With the `name` parameter set we set a custom name for the yielded
namedtuples:
>>> for row in df.itertuples(name='Animal'):
... print(row)
...
Animal(Index='dog', num_legs=4, num_wings=0)
Animal(Index='hawk', num_legs=2, num_wings=2)
"""
arrays = []
fields = list(self.columns)
if index:
arrays.append(self.index)
fields.insert(0, "Index")
# use integer indexing because of possible duplicate column names
arrays.extend(self.iloc[:, k] for k in range(len(self.columns)))
# Python versions before 3.7 support at most 255 arguments to constructors
can_return_named_tuples = PY37 or len(self.columns) + index < 255
if name is not None and can_return_named_tuples:
itertuple = collections.namedtuple(name, fields, rename=True)
return map(itertuple._make, zip(*arrays))
# fallback to regular tuples
return zip(*arrays)
def __len__(self) -> int:
"""
Returns length of info axis, but here we use the index.
"""
return len(self.index)
def dot(self, other):
"""
Compute the matrix multiplication between the DataFrame and other.
This method computes the matrix product between the DataFrame and the
values of an other Series, DataFrame or a numpy array.
It can also be called using ``self @ other`` in Python >= 3.5.
Parameters
----------
other : Series, DataFrame or array-like
The other object to compute the matrix product with.
Returns
-------
Series or DataFrame
If other is a Series, return the matrix product between self and
other as a Serie. If other is a DataFrame or a numpy.array, return
the matrix product of self and other in a DataFrame of a np.array.
See Also
--------
Series.dot: Similar method for Series.
Notes
-----
The dimensions of DataFrame and other must be compatible in order to
compute the matrix multiplication. In addition, the column names of
DataFrame and the index of other must contain the same values, as they
will be aligned prior to the multiplication.
The dot method for Series computes the inner product, instead of the
matrix product here.
Examples
--------
Here we multiply a DataFrame with a Series.
>>> df = pd.DataFrame([[0, 1, -2, -1], [1, 1, 1, 1]])
>>> s = pd.Series([1, 1, 2, 1])
>>> df.dot(s)
0 -4
1 5
dtype: int64
Here we multiply a DataFrame with another DataFrame.
>>> other = pd.DataFrame([[0, 1], [1, 2], [-1, -1], [2, 0]])
>>> df.dot(other)
0 1
0 1 4
1 2 2
Note that the dot method give the same result as @
>>> df @ other
0 1
0 1 4
1 2 2
The dot method works also if other is an np.array.
>>> arr = np.array([[0, 1], [1, 2], [-1, -1], [2, 0]])
>>> df.dot(arr)
0 1
0 1 4
1 2 2
Note how shuffling of the objects does not change the result.
>>> s2 = s.reindex([1, 0, 2, 3])
>>> df.dot(s2)
0 -4
1 5
dtype: int64
"""
if isinstance(other, (Series, DataFrame)):
common = self.columns.union(other.index)
if len(common) > len(self.columns) or len(common) > len(other.index):
raise ValueError("matrices are not aligned")
left = self.reindex(columns=common, copy=False)
right = other.reindex(index=common, copy=False)
lvals = left.values
rvals = right.values
else:
left = self
lvals = self.values
rvals = np.asarray(other)
if lvals.shape[1] != rvals.shape[0]:
raise ValueError(
f"Dot product shape mismatch, {lvals.shape} vs {rvals.shape}"
)
if isinstance(other, DataFrame):
return self._constructor(
np.dot(lvals, rvals), index=left.index, columns=other.columns
)
elif isinstance(other, Series):
return Series(np.dot(lvals, rvals), index=left.index)
elif isinstance(rvals, (np.ndarray, Index)):
result = np.dot(lvals, rvals)
if result.ndim == 2:
return self._constructor(result, index=left.index)
else:
return Series(result, index=left.index)
else: # pragma: no cover
raise TypeError(f"unsupported type: {type(other)}")
def __matmul__(self, other):
"""
Matrix multiplication using binary `@` operator in Python>=3.5.
"""
return self.dot(other)
def __rmatmul__(self, other):
"""
Matrix multiplication using binary `@` operator in Python>=3.5.
"""
return self.T.dot(np.transpose(other)).T
# ----------------------------------------------------------------------
# IO methods (to / from other formats)
@classmethod
def from_dict(cls, data, orient="columns", dtype=None, columns=None) -> "DataFrame":
"""
Construct DataFrame from dict of array-like or dicts.
Creates DataFrame object from dictionary by columns or by index
allowing dtype specification.
Parameters
----------
data : dict
Of the form {field : array-like} or {field : dict}.
orient : {'columns', 'index'}, default 'columns'
The "orientation" of the data. If the keys of the passed dict
should be the columns of the resulting DataFrame, pass 'columns'
(default). Otherwise if the keys should be rows, pass 'index'.
dtype : dtype, default None
Data type to force, otherwise infer.
columns : list, default None
Column labels to use when ``orient='index'``. Raises a ValueError
if used with ``orient='columns'``.
.. versionadded:: 0.23.0
Returns
-------
DataFrame
See Also
--------
DataFrame.from_records : DataFrame from ndarray (structured
dtype), list of tuples, dict, or DataFrame.
DataFrame : DataFrame object creation using constructor.
Examples
--------
By default the keys of the dict become the DataFrame columns:
>>> data = {'col_1': [3, 2, 1, 0], 'col_2': ['a', 'b', 'c', 'd']}
>>> pd.DataFrame.from_dict(data)
col_1 col_2
0 3 a
1 2 b
2 1 c
3 0 d
Specify ``orient='index'`` to create the DataFrame using dictionary
keys as rows:
>>> data = {'row_1': [3, 2, 1, 0], 'row_2': ['a', 'b', 'c', 'd']}
>>> pd.DataFrame.from_dict(data, orient='index')
0 1 2 3
row_1 3 2 1 0
row_2 a b c d
When using the 'index' orientation, the column names can be
specified manually:
>>> pd.DataFrame.from_dict(data, orient='index',
... columns=['A', 'B', 'C', 'D'])
A B C D
row_1 3 2 1 0
row_2 a b c d
"""
index = None
orient = orient.lower()
if orient == "index":
if len(data) > 0:
# TODO speed up Series case
if isinstance(list(data.values())[0], (Series, dict)):
data = _from_nested_dict(data)
else:
data, index = list(data.values()), list(data.keys())
elif orient == "columns":
if columns is not None:
raise ValueError("cannot use columns parameter with orient='columns'")
else: # pragma: no cover
raise ValueError("only recognize index or columns for orient")
return cls(data, index=index, columns=columns, dtype=dtype)
def to_numpy(self, dtype=None, copy=False) -> np.ndarray:
"""
Convert the DataFrame to a NumPy array.
.. versionadded:: 0.24.0
By default, the dtype of the returned array will be the common NumPy
dtype of all types in the DataFrame. For example, if the dtypes are
``float16`` and ``float32``, the results dtype will be ``float32``.
This may require copying data and coercing values, which may be
expensive.
Parameters
----------
dtype : str or numpy.dtype, optional
The dtype to pass to :meth:`numpy.asarray`.
copy : bool, default False
Whether to ensure that the returned value is a not a view on
another array. Note that ``copy=False`` does not *ensure* that
``to_numpy()`` is no-copy. Rather, ``copy=True`` ensure that
a copy is made, even if not strictly necessary.
Returns
-------
numpy.ndarray
See Also
--------
Series.to_numpy : Similar method for Series.
Examples
--------
>>> pd.DataFrame({"A": [1, 2], "B": [3, 4]}).to_numpy()
array([[1, 3],
[2, 4]])
With heterogeneous data, the lowest common type will have to
be used.
>>> df = pd.DataFrame({"A": [1, 2], "B": [3.0, 4.5]})
>>> df.to_numpy()
array([[1. , 3. ],
[2. , 4.5]])
For a mix of numeric and non-numeric types, the output array will
have object dtype.
>>> df['C'] = pd.date_range('2000', periods=2)
>>> df.to_numpy()
array([[1, 3.0, Timestamp('2000-01-01 00:00:00')],
[2, 4.5, Timestamp('2000-01-02 00:00:00')]], dtype=object)
"""
result = np.array(self.values, dtype=dtype, copy=copy)
return result
def to_dict(self, orient="dict", into=dict):
"""
Convert the DataFrame to a dictionary.
The type of the key-value pairs can be customized with the parameters
(see below).
Parameters
----------
orient : str {'dict', 'list', 'series', 'split', 'records', 'index'}
Determines the type of the values of the dictionary.
- 'dict' (default) : dict like {column -> {index -> value}}
- 'list' : dict like {column -> [values]}
- 'series' : dict like {column -> Series(values)}
- 'split' : dict like
{'index' -> [index], 'columns' -> [columns], 'data' -> [values]}
- 'records' : list like
[{column -> value}, ... , {column -> value}]
- 'index' : dict like {index -> {column -> value}}
Abbreviations are allowed. `s` indicates `series` and `sp`
indicates `split`.
into : class, default dict
The collections.abc.Mapping subclass used for all Mappings
in the return value. Can be the actual class or an empty
instance of the mapping type you want. If you want a
collections.defaultdict, you must pass it initialized.
.. versionadded:: 0.21.0
Returns
-------
dict, list or collections.abc.Mapping
Return a collections.abc.Mapping object representing the DataFrame.
The resulting transformation depends on the `orient` parameter.
See Also
--------
DataFrame.from_dict: Create a DataFrame from a dictionary.
DataFrame.to_json: Convert a DataFrame to JSON format.
Examples
--------
>>> df = pd.DataFrame({'col1': [1, 2],
... 'col2': [0.5, 0.75]},
... index=['row1', 'row2'])
>>> df
col1 col2
row1 1 0.50
row2 2 0.75
>>> df.to_dict()
{'col1': {'row1': 1, 'row2': 2}, 'col2': {'row1': 0.5, 'row2': 0.75}}
You can specify the return orientation.
>>> df.to_dict('series')
{'col1': row1 1
row2 2
Name: col1, dtype: int64,
'col2': row1 0.50
row2 0.75
Name: col2, dtype: float64}
>>> df.to_dict('split')
{'index': ['row1', 'row2'], 'columns': ['col1', 'col2'],
'data': [[1, 0.5], [2, 0.75]]}
>>> df.to_dict('records')
[{'col1': 1, 'col2': 0.5}, {'col1': 2, 'col2': 0.75}]
>>> df.to_dict('index')
{'row1': {'col1': 1, 'col2': 0.5}, 'row2': {'col1': 2, 'col2': 0.75}}
You can also specify the mapping type.
>>> from collections import OrderedDict, defaultdict
>>> df.to_dict(into=OrderedDict)
OrderedDict([('col1', OrderedDict([('row1', 1), ('row2', 2)])),
('col2', OrderedDict([('row1', 0.5), ('row2', 0.75)]))])
If you want a `defaultdict`, you need to initialize it:
>>> dd = defaultdict(list)
>>> df.to_dict('records', into=dd)
[defaultdict(<class 'list'>, {'col1': 1, 'col2': 0.5}),
defaultdict(<class 'list'>, {'col1': 2, 'col2': 0.75})]
"""
if not self.columns.is_unique:
warnings.warn(
"DataFrame columns are not unique, some columns will be omitted.",
UserWarning,
stacklevel=2,
)
# GH16122
into_c = com.standardize_mapping(into)
if orient.lower().startswith("d"):
return into_c((k, v.to_dict(into)) for k, v in self.items())
elif orient.lower().startswith("l"):
return into_c((k, v.tolist()) for k, v in self.items())
elif orient.lower().startswith("sp"):
return into_c(
(
("index", self.index.tolist()),
("columns", self.columns.tolist()),
(
"data",
[
list(map(com.maybe_box_datetimelike, t))
for t in self.itertuples(index=False, name=None)
],
),
)
)
elif orient.lower().startswith("s"):
return into_c((k, com.maybe_box_datetimelike(v)) for k, v in self.items())
elif orient.lower().startswith("r"):
columns = self.columns.tolist()
rows = (
dict(zip(columns, row))
for row in self.itertuples(index=False, name=None)
)
return [
into_c((k, com.maybe_box_datetimelike(v)) for k, v in row.items())
for row in rows
]
elif orient.lower().startswith("i"):
if not self.index.is_unique:
raise ValueError("DataFrame index must be unique for orient='index'.")
return into_c(
(t[0], dict(zip(self.columns, t[1:])))
for t in self.itertuples(name=None)
)
else:
raise ValueError(f"orient '{orient}' not understood")
def to_gbq(
self,
destination_table,
project_id=None,
chunksize=None,
reauth=False,
if_exists="fail",
auth_local_webserver=False,
table_schema=None,
location=None,
progress_bar=True,
credentials=None,
) -> None:
"""
Write a DataFrame to a Google BigQuery table.
This function requires the `pandas-gbq package
<https://pandas-gbq.readthedocs.io>`__.
See the `How to authenticate with Google BigQuery
<https://pandas-gbq.readthedocs.io/en/latest/howto/authentication.html>`__
guide for authentication instructions.
Parameters
----------
destination_table : str
Name of table to be written, in the form ``dataset.tablename``.
project_id : str, optional
Google BigQuery Account project ID. Optional when available from
the environment.
chunksize : int, optional
Number of rows to be inserted in each chunk from the dataframe.
Set to ``None`` to load the whole dataframe at once.
reauth : bool, default False
Force Google BigQuery to re-authenticate the user. This is useful
if multiple accounts are used.
if_exists : str, default 'fail'
Behavior when the destination table exists. Value can be one of:
``'fail'``
If table exists raise pandas_gbq.gbq.TableCreationError.
``'replace'``
If table exists, drop it, recreate it, and insert data.
``'append'``
If table exists, insert data. Create if does not exist.
auth_local_webserver : bool, default False
Use the `local webserver flow`_ instead of the `console flow`_
when getting user credentials.
.. _local webserver flow:
https://google-auth-oauthlib.readthedocs.io/en/latest/reference/google_auth_oauthlib.flow.html#google_auth_oauthlib.flow.InstalledAppFlow.run_local_server
.. _console flow:
https://google-auth-oauthlib.readthedocs.io/en/latest/reference/google_auth_oauthlib.flow.html#google_auth_oauthlib.flow.InstalledAppFlow.run_console
*New in version 0.2.0 of pandas-gbq*.
table_schema : list of dicts, optional
List of BigQuery table fields to which according DataFrame
columns conform to, e.g. ``[{'name': 'col1', 'type':
'STRING'},...]``. If schema is not provided, it will be
generated according to dtypes of DataFrame columns. See
BigQuery API documentation on available names of a field.
*New in version 0.3.1 of pandas-gbq*.
location : str, optional
Location where the load job should run. See the `BigQuery locations
documentation
<https://cloud.google.com/bigquery/docs/dataset-locations>`__ for a
list of available locations. The location must match that of the
target dataset.
*New in version 0.5.0 of pandas-gbq*.
progress_bar : bool, default True
Use the library `tqdm` to show the progress bar for the upload,
chunk by chunk.
*New in version 0.5.0 of pandas-gbq*.
credentials : google.auth.credentials.Credentials, optional
Credentials for accessing Google APIs. Use this parameter to
override default credentials, such as to use Compute Engine
:class:`google.auth.compute_engine.Credentials` or Service
Account :class:`google.oauth2.service_account.Credentials`
directly.
*New in version 0.8.0 of pandas-gbq*.
.. versionadded:: 0.24.0
See Also
--------
pandas_gbq.to_gbq : This function in the pandas-gbq library.
read_gbq : Read a DataFrame from Google BigQuery.
"""
from pandas.io import gbq
gbq.to_gbq(
self,
destination_table,
project_id=project_id,
chunksize=chunksize,
reauth=reauth,
if_exists=if_exists,
auth_local_webserver=auth_local_webserver,
table_schema=table_schema,
location=location,
progress_bar=progress_bar,
credentials=credentials,
)
@classmethod
def from_records(
cls,
data,
index=None,
exclude=None,
columns=None,
coerce_float=False,
nrows=None,
) -> "DataFrame":
"""
Convert structured or record ndarray to DataFrame.
Parameters
----------
data : ndarray (structured dtype), list of tuples, dict, or DataFrame
index : str, list of fields, array-like
Field of array to use as the index, alternately a specific set of
input labels to use.
exclude : sequence, default None
Columns or fields to exclude.
columns : sequence, default None
Column names to use. If the passed data do not have names
associated with them, this argument provides names for the
columns. Otherwise this argument indicates the order of the columns
in the result (any names not found in the data will become all-NA
columns).
coerce_float : bool, default False
Attempt to convert values of non-string, non-numeric objects (like
decimal.Decimal) to floating point, useful for SQL result sets.
nrows : int, default None
Number of rows to read if data is an iterator.
Returns
-------
DataFrame
"""
# Make a copy of the input columns so we can modify it
if columns is not None:
columns = ensure_index(columns)
if is_iterator(data):
if nrows == 0:
return cls()
try:
first_row = next(data)
except StopIteration:
return cls(index=index, columns=columns)
dtype = None
if hasattr(first_row, "dtype") and first_row.dtype.names:
dtype = first_row.dtype
values = [first_row]
if nrows is None:
values += data
else:
values.extend(itertools.islice(data, nrows - 1))
if dtype is not None:
data = np.array(values, dtype=dtype)
else:
data = values
if isinstance(data, dict):
if columns is None:
columns = arr_columns = ensure_index(sorted(data))
arrays = [data[k] for k in columns]
else:
arrays = []
arr_columns = []
for k, v in data.items():
if k in columns:
arr_columns.append(k)
arrays.append(v)
arrays, arr_columns = reorder_arrays(arrays, arr_columns, columns)
elif isinstance(data, (np.ndarray, DataFrame)):
arrays, columns = to_arrays(data, columns)
if columns is not None:
columns = ensure_index(columns)
arr_columns = columns
else:
arrays, arr_columns = to_arrays(data, columns, coerce_float=coerce_float)
arr_columns = ensure_index(arr_columns)
if columns is not None:
columns = ensure_index(columns)
else:
columns = arr_columns
if exclude is None:
exclude = set()
else:
exclude = set(exclude)
result_index = None
if index is not None:
if isinstance(index, str) or not hasattr(index, "__iter__"):
i = columns.get_loc(index)
exclude.add(index)
if len(arrays) > 0:
result_index = Index(arrays[i], name=index)
else:
result_index = Index([], name=index)
else:
try:
index_data = [arrays[arr_columns.get_loc(field)] for field in index]
except (KeyError, TypeError):
# raised by get_loc, see GH#29258
result_index = index
else:
result_index = ensure_index_from_sequences(index_data, names=index)
exclude.update(index)
if any(exclude):
arr_exclude = [x for x in exclude if x in arr_columns]
to_remove = [arr_columns.get_loc(col) for col in arr_exclude]
arrays = [v for i, v in enumerate(arrays) if i not in to_remove]
arr_columns = arr_columns.drop(arr_exclude)
columns = columns.drop(exclude)
mgr = arrays_to_mgr(arrays, arr_columns, result_index, columns)
return cls(mgr)
def to_records(
self, index=True, column_dtypes=None, index_dtypes=None
) -> np.recarray:
"""
Convert DataFrame to a NumPy record array.
Index will be included as the first field of the record array if
requested.
Parameters
----------
index : bool, default True
Include index in resulting record array, stored in 'index'
field or using the index label, if set.
column_dtypes : str, type, dict, default None
.. versionadded:: 0.24.0
If a string or type, the data type to store all columns. If
a dictionary, a mapping of column names and indices (zero-indexed)
to specific data types.
index_dtypes : str, type, dict, default None
.. versionadded:: 0.24.0
If a string or type, the data type to store all index levels. If
a dictionary, a mapping of index level names and indices
(zero-indexed) to specific data types.
This mapping is applied only if `index=True`.
Returns
-------
numpy.recarray
NumPy ndarray with the DataFrame labels as fields and each row
of the DataFrame as entries.
See Also
--------
DataFrame.from_records: Convert structured or record ndarray
to DataFrame.
numpy.recarray: An ndarray that allows field access using
attributes, analogous to typed columns in a
spreadsheet.
Examples
--------
>>> df = pd.DataFrame({'A': [1, 2], 'B': [0.5, 0.75]},
... index=['a', 'b'])
>>> df
A B
a 1 0.50
b 2 0.75
>>> df.to_records()
rec.array([('a', 1, 0.5 ), ('b', 2, 0.75)],
dtype=[('index', 'O'), ('A', '<i8'), ('B', '<f8')])
If the DataFrame index has no label then the recarray field name
is set to 'index'. If the index has a label then this is used as the
field name:
>>> df.index = df.index.rename("I")
>>> df.to_records()
rec.array([('a', 1, 0.5 ), ('b', 2, 0.75)],
dtype=[('I', 'O'), ('A', '<i8'), ('B', '<f8')])
The index can be excluded from the record array:
>>> df.to_records(index=False)
rec.array([(1, 0.5 ), (2, 0.75)],
dtype=[('A', '<i8'), ('B', '<f8')])
Data types can be specified for the columns:
>>> df.to_records(column_dtypes={"A": "int32"})
rec.array([('a', 1, 0.5 ), ('b', 2, 0.75)],
dtype=[('I', 'O'), ('A', '<i4'), ('B', '<f8')])
As well as for the index:
>>> df.to_records(index_dtypes="<S2")
rec.array([(b'a', 1, 0.5 ), (b'b', 2, 0.75)],
dtype=[('I', 'S2'), ('A', '<i8'), ('B', '<f8')])
>>> index_dtypes = f"<S{df.index.str.len().max()}"
>>> df.to_records(index_dtypes=index_dtypes)
rec.array([(b'a', 1, 0.5 ), (b'b', 2, 0.75)],
dtype=[('I', 'S1'), ('A', '<i8'), ('B', '<f8')])
"""
if index:
if isinstance(self.index, ABCMultiIndex):
# array of tuples to numpy cols. copy copy copy
ix_vals = list(map(np.array, zip(*self.index.values)))
else:
ix_vals = [self.index.values]
arrays = ix_vals + [self[c]._internal_get_values() for c in self.columns]
count = 0
index_names = list(self.index.names)
if isinstance(self.index, ABCMultiIndex):
for i, n in enumerate(index_names):
if n is None:
index_names[i] = f"level_{count}"
count += 1
elif index_names[0] is None:
index_names = ["index"]
names = [str(name) for name in itertools.chain(index_names, self.columns)]
else:
arrays = [self[c]._internal_get_values() for c in self.columns]
names = [str(c) for c in self.columns]
index_names = []
index_len = len(index_names)
formats = []
for i, v in enumerate(arrays):
index = i
# When the names and arrays are collected, we
# first collect those in the DataFrame's index,
# followed by those in its columns.
#
# Thus, the total length of the array is:
# len(index_names) + len(DataFrame.columns).
#
# This check allows us to see whether we are
# handling a name / array in the index or column.
if index < index_len:
dtype_mapping = index_dtypes
name = index_names[index]
else:
index -= index_len
dtype_mapping = column_dtypes
name = self.columns[index]
# We have a dictionary, so we get the data type
# associated with the index or column (which can
# be denoted by its name in the DataFrame or its
# position in DataFrame's array of indices or
# columns, whichever is applicable.
if is_dict_like(dtype_mapping):
if name in dtype_mapping:
dtype_mapping = dtype_mapping[name]
elif index in dtype_mapping:
dtype_mapping = dtype_mapping[index]
else:
dtype_mapping = None
# If no mapping can be found, use the array's
# dtype attribute for formatting.
#
# A valid dtype must either be a type or
# string naming a type.
if dtype_mapping is None:
formats.append(v.dtype)
elif isinstance(dtype_mapping, (type, np.dtype, str)):
formats.append(dtype_mapping)
else:
element = "row" if i < index_len else "column"
msg = f"Invalid dtype {dtype_mapping} specified for {element} {name}"
raise ValueError(msg)
return np.rec.fromarrays(arrays, dtype={"names": names, "formats": formats})
@classmethod
def _from_arrays(cls, arrays, columns, index, dtype=None) -> "DataFrame":
mgr = arrays_to_mgr(arrays, columns, index, columns, dtype=dtype)
return cls(mgr)
@deprecate_kwarg(old_arg_name="fname", new_arg_name="path")
def to_stata(
self,
path: FilePathOrBuffer,
convert_dates: Optional[Dict[Label, str]] = None,
write_index: bool = True,
byteorder: Optional[str] = None,
time_stamp: Optional[datetime.datetime] = None,
data_label: Optional[str] = None,
variable_labels: Optional[Dict[Label, str]] = None,
version: Optional[int] = 114,
convert_strl: Optional[Sequence[Label]] = None,
) -> None:
"""
Export DataFrame object to Stata dta format.
Writes the DataFrame to a Stata dataset file.
"dta" files contain a Stata dataset.
Parameters
----------
path : str, buffer or path object
String, path object (pathlib.Path or py._path.local.LocalPath) or
object implementing a binary write() function. If using a buffer
then the buffer will not be automatically closed after the file
data has been written.
.. versionchanged:: 1.0.0
Previously this was "fname"
convert_dates : dict
Dictionary mapping columns containing datetime types to stata
internal format to use when writing the dates. Options are 'tc',
'td', 'tm', 'tw', 'th', 'tq', 'ty'. Column can be either an integer
or a name. Datetime columns that do not have a conversion type
specified will be converted to 'tc'. Raises NotImplementedError if
a datetime column has timezone information.
write_index : bool
Write the index to Stata dataset.
byteorder : str
Can be ">", "<", "little", or "big". default is `sys.byteorder`.
time_stamp : datetime
A datetime to use as file creation date. Default is the current
time.
data_label : str, optional
A label for the data set. Must be 80 characters or smaller.
variable_labels : dict
Dictionary containing columns as keys and variable labels as
values. Each label must be 80 characters or smaller.
version : {114, 117, 118, 119, None}, default 114
Version to use in the output dta file. Set to None to let pandas
decide between 118 or 119 formats depending on the number of
columns in the frame. Version 114 can be read by Stata 10 and
later. Version 117 can be read by Stata 13 or later. Version 118
is supported in Stata 14 and later. Version 119 is supported in
Stata 15 and later. Version 114 limits string variables to 244
characters or fewer while versions 117 and later allow strings
with lengths up to 2,000,000 characters. Versions 118 and 119
support Unicode characters, and version 119 supports more than
32,767 variables.
.. versionadded:: 0.23.0
.. versionchanged:: 1.0.0
Added support for formats 118 and 119.
convert_strl : list, optional
List of column names to convert to string columns to Stata StrL
format. Only available if version is 117. Storing strings in the
StrL format can produce smaller dta files if strings have more than
8 characters and values are repeated.
.. versionadded:: 0.23.0
Raises
------
NotImplementedError
* If datetimes contain timezone information
* Column dtype is not representable in Stata
ValueError
* Columns listed in convert_dates are neither datetime64[ns]
or datetime.datetime
* Column listed in convert_dates is not in DataFrame
* Categorical label contains more than 32,000 characters
See Also
--------
read_stata : Import Stata data files.
io.stata.StataWriter : Low-level writer for Stata data files.
io.stata.StataWriter117 : Low-level writer for version 117 files.
Examples
--------
>>> df = pd.DataFrame({'animal': ['falcon', 'parrot', 'falcon',
... 'parrot'],
... 'speed': [350, 18, 361, 15]})
>>> df.to_stata('animals.dta') # doctest: +SKIP
"""
if version not in (114, 117, 118, 119, None):
raise ValueError("Only formats 114, 117, 118 and 119 are supported.")
if version == 114:
if convert_strl is not None:
raise ValueError("strl is not supported in format 114")
from pandas.io.stata import StataWriter as statawriter
elif version == 117:
# mypy: Name 'statawriter' already defined (possibly by an import)
from pandas.io.stata import StataWriter117 as statawriter # type: ignore
else: # versions 118 and 119
# mypy: Name 'statawriter' already defined (possibly by an import)
from pandas.io.stata import StataWriterUTF8 as statawriter # type:ignore
kwargs: Dict[str, Any] = {}
if version is None or version >= 117:
# strl conversion is only supported >= 117
kwargs["convert_strl"] = convert_strl
if version is None or version >= 118:
# Specifying the version is only supported for UTF8 (118 or 119)
kwargs["version"] = version
# mypy: Too many arguments for "StataWriter"
writer = statawriter( # type: ignore
path,
self,
convert_dates=convert_dates,
byteorder=byteorder,
time_stamp=time_stamp,
data_label=data_label,
write_index=write_index,
variable_labels=variable_labels,
**kwargs,
)
writer.write_file()
@deprecate_kwarg(old_arg_name="fname", new_arg_name="path")
def to_feather(self, path) -> None:
"""
Write out the binary feather-format for DataFrames.
Parameters
----------
path : str
String file path.
"""
from pandas.io.feather_format import to_feather
to_feather(self, path)
@Appender(
"""
Examples
--------
>>> df = pd.DataFrame(
... data={"animal_1": ["elk", "pig"], "animal_2": ["dog", "quetzal"]}
... )
>>> print(df.to_markdown())
| | animal_1 | animal_2 |
|---:|:-----------|:-----------|
| 0 | elk | dog |
| 1 | pig | quetzal |
"""
)
@Substitution(klass="DataFrame")
@Appender(_shared_docs["to_markdown"])
def to_markdown(
self, buf: Optional[IO[str]] = None, mode: Optional[str] = None, **kwargs
) -> Optional[str]:
kwargs.setdefault("headers", "keys")
kwargs.setdefault("tablefmt", "pipe")
tabulate = import_optional_dependency("tabulate")
result = tabulate.tabulate(self, **kwargs)
if buf is None:
return result
buf, _, _, _ = get_filepath_or_buffer(buf, mode=mode)
assert buf is not None # Help mypy.
buf.writelines(result)
return None
@deprecate_kwarg(old_arg_name="fname", new_arg_name="path")
def to_parquet(
self,
path,
engine="auto",
compression="snappy",
index=None,
partition_cols=None,
**kwargs,
) -> None:
"""
Write a DataFrame to the binary parquet format.
.. versionadded:: 0.21.0
This function writes the dataframe as a `parquet file
<https://parquet.apache.org/>`_. You can choose different parquet
backends, and have the option of compression. See
:ref:`the user guide <io.parquet>` for more details.
Parameters
----------
path : str
File path or Root Directory path. Will be used as Root Directory
path while writing a partitioned dataset.
.. versionchanged:: 1.0.0
Previously this was "fname"
engine : {'auto', 'pyarrow', 'fastparquet'}, default 'auto'
Parquet library to use. If 'auto', then the option
``io.parquet.engine`` is used. The default ``io.parquet.engine``
behavior is to try 'pyarrow', falling back to 'fastparquet' if
'pyarrow' is unavailable.
compression : {'snappy', 'gzip', 'brotli', None}, default 'snappy'
Name of the compression to use. Use ``None`` for no compression.
index : bool, default None
If ``True``, include the dataframe's index(es) in the file output.
If ``False``, they will not be written to the file.
If ``None``, similar to ``True`` the dataframe's index(es)
will be saved. However, instead of being saved as values,
the RangeIndex will be stored as a range in the metadata so it
doesn't require much space and is faster. Other indexes will
be included as columns in the file output.
.. versionadded:: 0.24.0
partition_cols : list, optional, default None
Column names by which to partition the dataset.
Columns are partitioned in the order they are given.
.. versionadded:: 0.24.0
**kwargs
Additional arguments passed to the parquet library. See
:ref:`pandas io <io.parquet>` for more details.
See Also
--------
read_parquet : Read a parquet file.
DataFrame.to_csv : Write a csv file.
DataFrame.to_sql : Write to a sql table.
DataFrame.to_hdf : Write to hdf.
Notes
-----
This function requires either the `fastparquet
<https://pypi.org/project/fastparquet>`_ or `pyarrow
<https://arrow.apache.org/docs/python/>`_ library.
Examples
--------
>>> df = pd.DataFrame(data={'col1': [1, 2], 'col2': [3, 4]})
>>> df.to_parquet('df.parquet.gzip',
... compression='gzip') # doctest: +SKIP
>>> pd.read_parquet('df.parquet.gzip') # doctest: +SKIP
col1 col2
0 1 3
1 2 4
"""
from pandas.io.parquet import to_parquet
to_parquet(
self,
path,
engine,
compression=compression,
index=index,
partition_cols=partition_cols,
**kwargs,
)
@Substitution(
header_type="bool",
header="Whether to print column labels, default True",
col_space_type="str or int",
col_space="The minimum width of each column in CSS length "
"units. An int is assumed to be px units.\n\n"
" .. versionadded:: 0.25.0\n"
" Ability to use str",
)
@Substitution(shared_params=fmt.common_docstring, returns=fmt.return_docstring)
def to_html(
self,
buf=None,
columns=None,
col_space=None,
header=True,
index=True,
na_rep="NaN",
formatters=None,
float_format=None,
sparsify=None,
index_names=True,
justify=None,
max_rows=None,
max_cols=None,
show_dimensions=False,
decimal=".",
bold_rows=True,
classes=None,
escape=True,
notebook=False,
border=None,
table_id=None,
render_links=False,
encoding=None,
):
"""
Render a DataFrame as an HTML table.
%(shared_params)s
bold_rows : bool, default True
Make the row labels bold in the output.
classes : str or list or tuple, default None
CSS class(es) to apply to the resulting html table.
escape : bool, default True
Convert the characters <, >, and & to HTML-safe sequences.
notebook : {True, False}, default False
Whether the generated HTML is for IPython Notebook.
border : int
A ``border=border`` attribute is included in the opening
`<table>` tag. Default ``pd.options.display.html.border``.
encoding : str, default "utf-8"
Set character encoding.
.. versionadded:: 1.0
table_id : str, optional
A css id is included in the opening `<table>` tag if specified.
.. versionadded:: 0.23.0
render_links : bool, default False
Convert URLs to HTML links.
.. versionadded:: 0.24.0
%(returns)s
See Also
--------
to_string : Convert DataFrame to a string.
"""
if justify is not None and justify not in fmt._VALID_JUSTIFY_PARAMETERS:
raise ValueError("Invalid value for justify parameter")
formatter = fmt.DataFrameFormatter(
self,
columns=columns,
col_space=col_space,
na_rep=na_rep,
formatters=formatters,
float_format=float_format,
sparsify=sparsify,
justify=justify,
index_names=index_names,
header=header,
index=index,
bold_rows=bold_rows,
escape=escape,
max_rows=max_rows,
max_cols=max_cols,
show_dimensions=show_dimensions,
decimal=decimal,
table_id=table_id,
render_links=render_links,
)
# TODO: a generic formatter wld b in DataFrameFormatter
return formatter.to_html(
buf=buf,
classes=classes,
notebook=notebook,
border=border,
encoding=encoding,
)
# ----------------------------------------------------------------------
@Appender(info.__doc__)
def info(
self, verbose=None, buf=None, max_cols=None, memory_usage=None, null_counts=None
) -> None:
return info(self, verbose, buf, max_cols, memory_usage, null_counts)
def memory_usage(self, index=True, deep=False) -> Series:
"""
Return the memory usage of each column in bytes.
The memory usage can optionally include the contribution of
the index and elements of `object` dtype.
This value is displayed in `DataFrame.info` by default. This can be
suppressed by setting ``pandas.options.display.memory_usage`` to False.
Parameters
----------
index : bool, default True
Specifies whether to include the memory usage of the DataFrame's
index in returned Series. If ``index=True``, the memory usage of
the index is the first item in the output.
deep : bool, default False
If True, introspect the data deeply by interrogating
`object` dtypes for system-level memory consumption, and include
it in the returned values.
Returns
-------
Series
A Series whose index is the original column names and whose values
is the memory usage of each column in bytes.
See Also
--------
numpy.ndarray.nbytes : Total bytes consumed by the elements of an
ndarray.
Series.memory_usage : Bytes consumed by a Series.
Categorical : Memory-efficient array for string values with
many repeated values.
DataFrame.info : Concise summary of a DataFrame.
Examples
--------
>>> dtypes = ['int64', 'float64', 'complex128', 'object', 'bool']
>>> data = dict([(t, np.ones(shape=5000).astype(t))
... for t in dtypes])
>>> df = pd.DataFrame(data)
>>> df.head()
int64 float64 complex128 object bool
0 1 1.0 1.000000+0.000000j 1 True
1 1 1.0 1.000000+0.000000j 1 True
2 1 1.0 1.000000+0.000000j 1 True
3 1 1.0 1.000000+0.000000j 1 True
4 1 1.0 1.000000+0.000000j 1 True
>>> df.memory_usage()
Index 128
int64 40000
float64 40000
complex128 80000
object 40000
bool 5000
dtype: int64
>>> df.memory_usage(index=False)
int64 40000
float64 40000
complex128 80000
object 40000
bool 5000
dtype: int64
The memory footprint of `object` dtype columns is ignored by default:
>>> df.memory_usage(deep=True)
Index 128
int64 40000
float64 40000
complex128 80000
object 160000
bool 5000
dtype: int64
Use a Categorical for efficient storage of an object-dtype column with
many repeated values.
>>> df['object'].astype('category').memory_usage(deep=True)
5216
"""
result = Series(
[c.memory_usage(index=False, deep=deep) for col, c in self.items()],
index=self.columns,
)
if index:
result = Series(self.index.memory_usage(deep=deep), index=["Index"]).append(
result
)
return result
def transpose(self, *args, copy: bool = False) -> "DataFrame":
"""
Transpose index and columns.
Reflect the DataFrame over its main diagonal by writing rows as columns
and vice-versa. The property :attr:`.T` is an accessor to the method
:meth:`transpose`.
Parameters
----------
*args : tuple, optional
Accepted for compatibility with NumPy.
copy : bool, default False
Whether to copy the data after transposing, even for DataFrames
with a single dtype.
Note that a copy is always required for mixed dtype DataFrames,
or for DataFrames with any extension types.
Returns
-------
DataFrame
The transposed DataFrame.
See Also
--------
numpy.transpose : Permute the dimensions of a given array.
Notes
-----
Transposing a DataFrame with mixed dtypes will result in a homogeneous
DataFrame with the `object` dtype. In such a case, a copy of the data
is always made.
Examples
--------
**Square DataFrame with homogeneous dtype**
>>> d1 = {'col1': [1, 2], 'col2': [3, 4]}
>>> df1 = pd.DataFrame(data=d1)
>>> df1
col1 col2
0 1 3
1 2 4
>>> df1_transposed = df1.T # or df1.transpose()
>>> df1_transposed
0 1
col1 1 2
col2 3 4
When the dtype is homogeneous in the original DataFrame, we get a
transposed DataFrame with the same dtype:
>>> df1.dtypes
col1 int64
col2 int64
dtype: object
>>> df1_transposed.dtypes
0 int64
1 int64
dtype: object
**Non-square DataFrame with mixed dtypes**
>>> d2 = {'name': ['Alice', 'Bob'],
... 'score': [9.5, 8],
... 'employed': [False, True],
... 'kids': [0, 0]}
>>> df2 = pd.DataFrame(data=d2)
>>> df2
name score employed kids
0 Alice 9.5 False 0
1 Bob 8.0 True 0
>>> df2_transposed = df2.T # or df2.transpose()
>>> df2_transposed
0 1
name Alice Bob
score 9.5 8
employed False True
kids 0 0
When the DataFrame has mixed dtypes, we get a transposed DataFrame with
the `object` dtype:
>>> df2.dtypes
name object
score float64
employed bool
kids int64
dtype: object
>>> df2_transposed.dtypes
0 object
1 object
dtype: object
"""
nv.validate_transpose(args, dict())
# construct the args
dtypes = list(self.dtypes)
if self._is_homogeneous_type and dtypes and is_extension_array_dtype(dtypes[0]):
# We have EAs with the same dtype. We can preserve that dtype in transpose.
dtype = dtypes[0]
arr_type = dtype.construct_array_type()
values = self.values
new_values = [arr_type._from_sequence(row, dtype=dtype) for row in values]
result = self._constructor(
dict(zip(self.index, new_values)), index=self.columns
)
else:
new_values = self.values.T
if copy:
new_values = new_values.copy()
result = self._constructor(
new_values, index=self.columns, columns=self.index
)
return result.__finalize__(self)
@property
def T(self) -> "DataFrame":
return self.transpose()
# ----------------------------------------------------------------------
# Indexing Methods
def _ixs(self, i: int, axis: int = 0):
"""
Parameters
----------
i : int
axis : int
Notes
-----
If slice passed, the resulting data will be a view.
"""
# irow
if axis == 0:
new_values = self._data.fast_xs(i)
# if we are a copy, mark as such
copy = isinstance(new_values, np.ndarray) and new_values.base is None
result = self._constructor_sliced(
new_values,
index=self.columns,
name=self.index[i],
dtype=new_values.dtype,
)
result._set_is_copy(self, copy=copy)
return result
# icol
else:
label = self.columns[i]
values = self._data.iget(i)
result = self._box_col_values(values, label)
# this is a cached value, mark it so
result._set_as_cached(label, self)
return result
def __getitem__(self, key):
key = lib.item_from_zerodim(key)
key = com.apply_if_callable(key, self)
if is_hashable(key):
# shortcut if the key is in columns
if self.columns.is_unique and key in self.columns:
if self.columns.nlevels > 1:
return self._getitem_multilevel(key)
return self._get_item_cache(key)
# Do we have a slicer (on rows)?
indexer = convert_to_index_sliceable(self, key)
if indexer is not None:
# either we have a slice or we have a string that can be converted
# to a slice for partial-string date indexing
return self._slice(indexer, axis=0)
# Do we have a (boolean) DataFrame?
if isinstance(key, DataFrame):
return self.where(key)
# Do we have a (boolean) 1d indexer?
if com.is_bool_indexer(key):
return self._getitem_bool_array(key)
# We are left with two options: a single key, and a collection of keys,
# We interpret tuples as collections only for non-MultiIndex
is_single_key = isinstance(key, tuple) or not is_list_like(key)
if is_single_key:
if self.columns.nlevels > 1:
return self._getitem_multilevel(key)
indexer = self.columns.get_loc(key)
if is_integer(indexer):
indexer = [indexer]
else:
if is_iterator(key):
key = list(key)
indexer = self.loc._get_listlike_indexer(key, axis=1, raise_missing=True)[1]
# take() does not accept boolean indexers
if getattr(indexer, "dtype", None) == bool:
indexer = np.where(indexer)[0]
data = self._take_with_is_copy(indexer, axis=1)
if is_single_key:
# What does looking for a single key in a non-unique index return?
# The behavior is inconsistent. It returns a Series, except when
# - the key itself is repeated (test on data.shape, #9519), or
# - we have a MultiIndex on columns (test on self.columns, #21309)
if data.shape[1] == 1 and not isinstance(self.columns, ABCMultiIndex):
data = data[key]
return data
def _getitem_bool_array(self, key):
# also raises Exception if object array with NA values
# warning here just in case -- previously __setitem__ was
# reindexing but __getitem__ was not; it seems more reasonable to
# go with the __setitem__ behavior since that is more consistent
# with all other indexing behavior
if isinstance(key, Series) and not key.index.equals(self.index):
warnings.warn(
"Boolean Series key will be reindexed to match DataFrame index.",
UserWarning,
stacklevel=3,
)
elif len(key) != len(self.index):
raise ValueError(
f"Item wrong length {len(key)} instead of {len(self.index)}."
)
# check_bool_indexer will throw exception if Series key cannot
# be reindexed to match DataFrame rows
key = check_bool_indexer(self.index, key)
indexer = key.nonzero()[0]
return self._take_with_is_copy(indexer, axis=0)
def _getitem_multilevel(self, key):
# self.columns is a MultiIndex
loc = self.columns.get_loc(key)
if isinstance(loc, (slice, Series, np.ndarray, Index)):
new_columns = self.columns[loc]
result_columns = maybe_droplevels(new_columns, key)
if self._is_mixed_type:
result = self.reindex(columns=new_columns)
result.columns = result_columns
else:
new_values = self.values[:, loc]
result = self._constructor(
new_values, index=self.index, columns=result_columns
)
result = result.__finalize__(self)
# If there is only one column being returned, and its name is
# either an empty string, or a tuple with an empty string as its
# first element, then treat the empty string as a placeholder
# and return the column as if the user had provided that empty
# string in the key. If the result is a Series, exclude the
# implied empty string from its name.
if len(result.columns) == 1:
top = result.columns[0]
if isinstance(top, tuple):
top = top[0]
if top == "":
result = result[""]
if isinstance(result, Series):
result = self._constructor_sliced(
result, index=self.index, name=key
)
result._set_is_copy(self)
return result
else:
return self._get_item_cache(key)
def _get_value(self, index, col, takeable: bool = False):
"""
Quickly retrieve single value at passed column and index.
Parameters
----------
index : row label
col : column label
takeable : interpret the index/col as indexers, default False
Returns
-------
scalar
"""
if takeable:
series = self._ixs(col, axis=1)
return series._values[index]
series = self._get_item_cache(col)
engine = self.index._engine
try:
loc = engine.get_loc(index)
return series._values[loc]
except KeyError:
# GH 20629
if self.index.nlevels > 1:
# partial indexing forbidden
raise
# we cannot handle direct indexing
# use positional
col = self.columns.get_loc(col)
index = self.index.get_loc(index)
return self._get_value(index, col, takeable=True)
def __setitem__(self, key, value):
key = com.apply_if_callable(key, self)
# see if we can slice the rows
indexer = convert_to_index_sliceable(self, key)
if indexer is not None:
# either we have a slice or we have a string that can be converted
# to a slice for partial-string date indexing
return self._setitem_slice(indexer, value)
if isinstance(key, DataFrame) or getattr(key, "ndim", None) == 2:
self._setitem_frame(key, value)
elif isinstance(key, (Series, np.ndarray, list, Index)):
self._setitem_array(key, value)
else:
# set column
self._set_item(key, value)
def _setitem_slice(self, key: slice, value):
# NB: we can't just use self.loc[key] = value because that
# operates on labels and we need to operate positional for
# backwards-compat, xref GH#31469
self._check_setitem_copy()
self.iloc._setitem_with_indexer(key, value)
def _setitem_array(self, key, value):
# also raises Exception if object array with NA values
if com.is_bool_indexer(key):
if len(key) != len(self.index):
raise ValueError(
f"Item wrong length {len(key)} instead of {len(self.index)}!"
)
key = check_bool_indexer(self.index, key)
indexer = key.nonzero()[0]
self._check_setitem_copy()
self.iloc._setitem_with_indexer(indexer, value)
else:
if isinstance(value, DataFrame):
if len(value.columns) != len(key):
raise ValueError("Columns must be same length as key")
for k1, k2 in zip(key, value.columns):
self[k1] = value[k2]
else:
self.loc._ensure_listlike_indexer(key, axis=1)
indexer = self.loc._get_listlike_indexer(
key, axis=1, raise_missing=False
)[1]
self._check_setitem_copy()
self.iloc._setitem_with_indexer((slice(None), indexer), value)
def _setitem_frame(self, key, value):
# support boolean setting with DataFrame input, e.g.
# df[df > df2] = 0
if isinstance(key, np.ndarray):
if key.shape != self.shape:
raise ValueError("Array conditional must be same shape as self")
key = self._constructor(key, **self._construct_axes_dict())
if key.values.size and not is_bool_dtype(key.values):
raise TypeError(
"Must pass DataFrame or 2-d ndarray with boolean values only"
)
self._check_inplace_setting(value)
self._check_setitem_copy()
self._where(-key, value, inplace=True)
def _iset_item(self, loc: int, value):
self._ensure_valid_index(value)
# technically _sanitize_column expects a label, not a position,
# but the behavior is the same as long as we pass broadcast=False
value = self._sanitize_column(loc, value, broadcast=False)
NDFrame._iset_item(self, loc, value)
# check if we are modifying a copy
# try to set first as we want an invalid
# value exception to occur first
if len(self):
self._check_setitem_copy()
def _set_item(self, key, value):
"""
Add series to DataFrame in specified column.
If series is a numpy-array (not a Series/TimeSeries), it must be the
same length as the DataFrames index or an error will be thrown.
Series/TimeSeries will be conformed to the DataFrames index to
ensure homogeneity.
"""
self._ensure_valid_index(value)
value = self._sanitize_column(key, value)
NDFrame._set_item(self, key, value)
# check if we are modifying a copy
# try to set first as we want an invalid
# value exception to occur first
if len(self):
self._check_setitem_copy()
def _set_value(self, index, col, value, takeable: bool = False):
"""
Put single value at passed column and index.
Parameters
----------
index : row label
col : column label
value : scalar
takeable : interpret the index/col as indexers, default False
"""
try:
if takeable is True:
series = self._ixs(col, axis=1)
series._set_value(index, value, takeable=True)
return
series = self._get_item_cache(col)
engine = self.index._engine
loc = engine.get_loc(index)
validate_numeric_casting(series.dtype, value)
series._values[loc] = value
# Note: trying to use series._set_value breaks tests in
# tests.frame.indexing.test_indexing and tests.indexing.test_partial
except (KeyError, TypeError):
# set using a non-recursive method & reset the cache
if takeable:
self.iloc[index, col] = value
else:
self.loc[index, col] = value
self._item_cache.pop(col, None)
def _ensure_valid_index(self, value):
"""
Ensure that if we don't have an index, that we can create one from the
passed value.
"""
# GH5632, make sure that we are a Series convertible
if not len(self.index) and is_list_like(value) and len(value):
try:
value = Series(value)
except (ValueError, NotImplementedError, TypeError) as err:
raise ValueError(
"Cannot set a frame with no defined index "
"and a value that cannot be converted to a Series"
) from err
self._data = self._data.reindex_axis(
value.index.copy(), axis=1, fill_value=np.nan
)
def _box_item_values(self, key, values):
items = self.columns[self.columns.get_loc(key)]
if values.ndim == 2:
return self._constructor(values.T, columns=items, index=self.index)
else:
return self._box_col_values(values, items)
def _box_col_values(self, values, items):
"""
Provide boxed values for a column.
"""
klass = self._constructor_sliced
return klass(values, index=self.index, name=items, fastpath=True)
# ----------------------------------------------------------------------
# Unsorted
def query(self, expr, inplace=False, **kwargs):
"""
Query the columns of a DataFrame with a boolean expression.
Parameters
----------
expr : str
The query string to evaluate.
You can refer to variables
in the environment by prefixing them with an '@' character like
``@a + b``.
You can refer to column names that contain spaces or operators by
surrounding them in backticks. This way you can also escape
names that start with a digit, or those that are a Python keyword.
Basically when it is not valid Python identifier. See notes down
for more details.
For example, if one of your columns is called ``a a`` and you want
to sum it with ``b``, your query should be ```a a` + b``.
.. versionadded:: 0.25.0
Backtick quoting introduced.
.. versionadded:: 1.0.0
Expanding functionality of backtick quoting for more than only spaces.
inplace : bool
Whether the query should modify the data in place or return
a modified copy.
**kwargs
See the documentation for :func:`eval` for complete details
on the keyword arguments accepted by :meth:`DataFrame.query`.
Returns
-------
DataFrame
DataFrame resulting from the provided query expression.
See Also
--------
eval : Evaluate a string describing operations on
DataFrame columns.
DataFrame.eval : Evaluate a string describing operations on
DataFrame columns.
Notes
-----
The result of the evaluation of this expression is first passed to
:attr:`DataFrame.loc` and if that fails because of a
multidimensional key (e.g., a DataFrame) then the result will be passed
to :meth:`DataFrame.__getitem__`.
This method uses the top-level :func:`eval` function to
evaluate the passed query.
The :meth:`~pandas.DataFrame.query` method uses a slightly
modified Python syntax by default. For example, the ``&`` and ``|``
(bitwise) operators have the precedence of their boolean cousins,
:keyword:`and` and :keyword:`or`. This *is* syntactically valid Python,
however the semantics are different.
You can change the semantics of the expression by passing the keyword
argument ``parser='python'``. This enforces the same semantics as
evaluation in Python space. Likewise, you can pass ``engine='python'``
to evaluate an expression using Python itself as a backend. This is not
recommended as it is inefficient compared to using ``numexpr`` as the
engine.
The :attr:`DataFrame.index` and
:attr:`DataFrame.columns` attributes of the
:class:`~pandas.DataFrame` instance are placed in the query namespace
by default, which allows you to treat both the index and columns of the
frame as a column in the frame.
The identifier ``index`` is used for the frame index; you can also
use the name of the index to identify it in a query. Please note that
Python keywords may not be used as identifiers.
For further details and examples see the ``query`` documentation in
:ref:`indexing <indexing.query>`.
*Backtick quoted variables*
Backtick quoted variables are parsed as literal Python code and
are converted internally to a Python valid identifier.
This can lead to the following problems.
During parsing a number of disallowed characters inside the backtick
quoted string are replaced by strings that are allowed as a Python identifier.
These characters include all operators in Python, the space character, the
question mark, the exclamation mark, the dollar sign, and the euro sign.
For other characters that fall outside the ASCII range (U+0001..U+007F)
and those that are not further specified in PEP 3131,
the query parser will raise an error.
This excludes whitespace different than the space character,
but also the hashtag (as it is used for comments) and the backtick
itself (backtick can also not be escaped).
In a special case, quotes that make a pair around a backtick can
confuse the parser.
For example, ```it's` > `that's``` will raise an error,
as it forms a quoted string (``'s > `that'``) with a backtick inside.
See also the Python documentation about lexical analysis
(https://docs.python.org/3/reference/lexical_analysis.html)
in combination with the source code in :mod:`pandas.core.computation.parsing`.
Examples
--------
>>> df = pd.DataFrame({'A': range(1, 6),
... 'B': range(10, 0, -2),
... 'C C': range(10, 5, -1)})
>>> df
A B C C
0 1 10 10
1 2 8 9
2 3 6 8
3 4 4 7
4 5 2 6
>>> df.query('A > B')
A B C C
4 5 2 6
The previous expression is equivalent to
>>> df[df.A > df.B]
A B C C
4 5 2 6
For columns with spaces in their name, you can use backtick quoting.
>>> df.query('B == `C C`')
A B C C
0 1 10 10
The previous expression is equivalent to
>>> df[df.B == df['C C']]
A B C C
0 1 10 10
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not isinstance(expr, str):
msg = f"expr must be a string to be evaluated, {type(expr)} given"
raise ValueError(msg)
kwargs["level"] = kwargs.pop("level", 0) + 1
kwargs["target"] = None
res = self.eval(expr, **kwargs)
try:
new_data = self.loc[res]
except ValueError:
# when res is multi-dimensional loc raises, but this is sometimes a
# valid query
new_data = self[res]
if inplace:
self._update_inplace(new_data)
else:
return new_data
def eval(self, expr, inplace=False, **kwargs):
"""
Evaluate a string describing operations on DataFrame columns.
Operates on columns only, not specific rows or elements. This allows
`eval` to run arbitrary code, which can make you vulnerable to code
injection if you pass user input to this function.
Parameters
----------
expr : str
The expression string to evaluate.
inplace : bool, default False
If the expression contains an assignment, whether to perform the
operation inplace and mutate the existing DataFrame. Otherwise,
a new DataFrame is returned.
**kwargs
See the documentation for :func:`eval` for complete details
on the keyword arguments accepted by
:meth:`~pandas.DataFrame.query`.
Returns
-------
ndarray, scalar, or pandas object
The result of the evaluation.
See Also
--------
DataFrame.query : Evaluates a boolean expression to query the columns
of a frame.
DataFrame.assign : Can evaluate an expression or function to create new
values for a column.
eval : Evaluate a Python expression as a string using various
backends.
Notes
-----
For more details see the API documentation for :func:`~eval`.
For detailed examples see :ref:`enhancing performance with eval
<enhancingperf.eval>`.
Examples
--------
>>> df = pd.DataFrame({'A': range(1, 6), 'B': range(10, 0, -2)})
>>> df
A B
0 1 10
1 2 8
2 3 6
3 4 4
4 5 2
>>> df.eval('A + B')
0 11
1 10
2 9
3 8
4 7
dtype: int64
Assignment is allowed though by default the original DataFrame is not
modified.
>>> df.eval('C = A + B')
A B C
0 1 10 11
1 2 8 10
2 3 6 9
3 4 4 8
4 5 2 7
>>> df
A B
0 1 10
1 2 8
2 3 6
3 4 4
4 5 2
Use ``inplace=True`` to modify the original DataFrame.
>>> df.eval('C = A + B', inplace=True)
>>> df
A B C
0 1 10 11
1 2 8 10
2 3 6 9
3 4 4 8
4 5 2 7
Multiple columns can be assigned to using multi-line expressions:
>>> df.eval(
... '''
... C = A + B
... D = A - B
... '''
... )
A B C D
0 1 10 11 -9
1 2 8 10 -6
2 3 6 9 -3
3 4 4 8 0
4 5 2 7 3
"""
from pandas.core.computation.eval import eval as _eval
inplace = validate_bool_kwarg(inplace, "inplace")
resolvers = kwargs.pop("resolvers", None)
kwargs["level"] = kwargs.pop("level", 0) + 1
if resolvers is None:
index_resolvers = self._get_index_resolvers()
column_resolvers = self._get_cleaned_column_resolvers()
resolvers = column_resolvers, index_resolvers
if "target" not in kwargs:
kwargs["target"] = self
kwargs["resolvers"] = kwargs.get("resolvers", ()) + tuple(resolvers)
return _eval(expr, inplace=inplace, **kwargs)
def select_dtypes(self, include=None, exclude=None) -> "DataFrame":
"""
Return a subset of the DataFrame's columns based on the column dtypes.
Parameters
----------
include, exclude : scalar or list-like
A selection of dtypes or strings to be included/excluded. At least
one of these parameters must be supplied.
Returns
-------
DataFrame
The subset of the frame including the dtypes in ``include`` and
excluding the dtypes in ``exclude``.
Raises
------
ValueError
* If both of ``include`` and ``exclude`` are empty
* If ``include`` and ``exclude`` have overlapping elements
* If any kind of string dtype is passed in.
Notes
-----
* To select all *numeric* types, use ``np.number`` or ``'number'``
* To select strings you must use the ``object`` dtype, but note that
this will return *all* object dtype columns
* See the `numpy dtype hierarchy
<https://docs.scipy.org/doc/numpy/reference/arrays.scalars.html>`__
* To select datetimes, use ``np.datetime64``, ``'datetime'`` or
``'datetime64'``
* To select timedeltas, use ``np.timedelta64``, ``'timedelta'`` or
``'timedelta64'``
* To select Pandas categorical dtypes, use ``'category'``
* To select Pandas datetimetz dtypes, use ``'datetimetz'`` (new in
0.20.0) or ``'datetime64[ns, tz]'``
Examples
--------
>>> df = pd.DataFrame({'a': [1, 2] * 3,
... 'b': [True, False] * 3,
... 'c': [1.0, 2.0] * 3})
>>> df
a b c
0 1 True 1.0
1 2 False 2.0
2 1 True 1.0
3 2 False 2.0
4 1 True 1.0
5 2 False 2.0
>>> df.select_dtypes(include='bool')
b
0 True
1 False
2 True
3 False
4 True
5 False
>>> df.select_dtypes(include=['float64'])
c
0 1.0
1 2.0
2 1.0
3 2.0
4 1.0
5 2.0
>>> df.select_dtypes(exclude=['int'])
b c
0 True 1.0
1 False 2.0
2 True 1.0
3 False 2.0
4 True 1.0
5 False 2.0
"""
if not is_list_like(include):
include = (include,) if include is not None else ()
if not is_list_like(exclude):
exclude = (exclude,) if exclude is not None else ()
selection = (frozenset(include), frozenset(exclude))
if not any(selection):
raise ValueError("at least one of include or exclude must be nonempty")
# convert the myriad valid dtypes object to a single representation
include = frozenset(infer_dtype_from_object(x) for x in include)
exclude = frozenset(infer_dtype_from_object(x) for x in exclude)
for dtypes in (include, exclude):
invalidate_string_dtypes(dtypes)
# can't both include AND exclude!
if not include.isdisjoint(exclude):
raise ValueError(f"include and exclude overlap on {(include & exclude)}")
# We raise when both include and exclude are empty
# Hence, we can just shrink the columns we want to keep
keep_these = np.full(self.shape[1], True)
def extract_unique_dtypes_from_dtypes_set(
dtypes_set: FrozenSet[Dtype], unique_dtypes: np.ndarray
) -> List[Dtype]:
extracted_dtypes = [
unique_dtype
for unique_dtype in unique_dtypes
if issubclass(unique_dtype.type, tuple(dtypes_set)) # type: ignore
]
return extracted_dtypes
unique_dtypes = self.dtypes.unique()
if include:
included_dtypes = extract_unique_dtypes_from_dtypes_set(
include, unique_dtypes
)
keep_these &= self.dtypes.isin(included_dtypes)
if exclude:
excluded_dtypes = extract_unique_dtypes_from_dtypes_set(
exclude, unique_dtypes
)
keep_these &= ~self.dtypes.isin(excluded_dtypes)
return self.iloc[:, keep_these.values]
def insert(self, loc, column, value, allow_duplicates=False) -> None:
"""
Insert column into DataFrame at specified location.
Raises a ValueError if `column` is already contained in the DataFrame,
unless `allow_duplicates` is set to True.
Parameters
----------
loc : int
Insertion index. Must verify 0 <= loc <= len(columns).
column : str, number, or hashable object
Label of the inserted column.
value : int, Series, or array-like
allow_duplicates : bool, optional
"""
self._ensure_valid_index(value)
value = self._sanitize_column(column, value, broadcast=False)
self._data.insert(loc, column, value, allow_duplicates=allow_duplicates)
def assign(self, **kwargs) -> "DataFrame":
r"""
Assign new columns to a DataFrame.
Returns a new object with all original columns in addition to new ones.
Existing columns that are re-assigned will be overwritten.
Parameters
----------
**kwargs : dict of {str: callable or Series}
The column names are keywords. If the values are
callable, they are computed on the DataFrame and
assigned to the new columns. The callable must not
change input DataFrame (though pandas doesn't check it).
If the values are not callable, (e.g. a Series, scalar, or array),
they are simply assigned.
Returns
-------
DataFrame
A new DataFrame with the new columns in addition to
all the existing columns.
Notes
-----
Assigning multiple columns within the same ``assign`` is possible.
Later items in '\*\*kwargs' may refer to newly created or modified
columns in 'df'; items are computed and assigned into 'df' in order.
.. versionchanged:: 0.23.0
Keyword argument order is maintained.
Examples
--------
>>> df = pd.DataFrame({'temp_c': [17.0, 25.0]},
... index=['Portland', 'Berkeley'])
>>> df
temp_c
Portland 17.0
Berkeley 25.0
Where the value is a callable, evaluated on `df`:
>>> df.assign(temp_f=lambda x: x.temp_c * 9 / 5 + 32)
temp_c temp_f
Portland 17.0 62.6
Berkeley 25.0 77.0
Alternatively, the same behavior can be achieved by directly
referencing an existing Series or sequence:
>>> df.assign(temp_f=df['temp_c'] * 9 / 5 + 32)
temp_c temp_f
Portland 17.0 62.6
Berkeley 25.0 77.0
You can create multiple columns within the same assign where one
of the columns depends on another one defined within the same assign:
>>> df.assign(temp_f=lambda x: x['temp_c'] * 9 / 5 + 32,
... temp_k=lambda x: (x['temp_f'] + 459.67) * 5 / 9)
temp_c temp_f temp_k
Portland 17.0 62.6 290.15
Berkeley 25.0 77.0 298.15
"""
data = self.copy()
for k, v in kwargs.items():
data[k] = com.apply_if_callable(v, data)
return data
def _sanitize_column(self, key, value, broadcast=True):
"""
Ensures new columns (which go into the BlockManager as new blocks) are
always copied and converted into an array.
Parameters
----------
key : object
value : scalar, Series, or array-like
broadcast : bool, default True
If ``key`` matches multiple duplicate column names in the
DataFrame, this parameter indicates whether ``value`` should be
tiled so that the returned array contains a (duplicated) column for
each occurrence of the key. If False, ``value`` will not be tiled.
Returns
-------
numpy.ndarray
"""
def reindexer(value):
# reindex if necessary
if value.index.equals(self.index) or not len(self.index):
value = value._values.copy()
else:
# GH 4107
try:
value = value.reindex(self.index)._values
except ValueError as err:
# raised in MultiIndex.from_tuples, see test_insert_error_msmgs
if not value.index.is_unique:
# duplicate axis
raise err
# other
raise TypeError(
"incompatible index of inserted column with frame index"
) from err
return value
if isinstance(value, Series):
value = reindexer(value)
elif isinstance(value, DataFrame):
# align right-hand-side columns if self.columns
# is multi-index and self[key] is a sub-frame
if isinstance(self.columns, ABCMultiIndex) and key in self.columns:
loc = self.columns.get_loc(key)
if isinstance(loc, (slice, Series, np.ndarray, Index)):
cols = maybe_droplevels(self.columns[loc], key)
if len(cols) and not cols.equals(value.columns):
value = value.reindex(cols, axis=1)
# now align rows
value = reindexer(value).T
elif isinstance(value, ExtensionArray):
# Explicitly copy here, instead of in sanitize_index,
# as sanitize_index won't copy an EA, even with copy=True
value = value.copy()
value = sanitize_index(value, self.index)
elif isinstance(value, Index) or is_sequence(value):
# turn me into an ndarray
value = sanitize_index(value, self.index)
if not isinstance(value, (np.ndarray, Index)):
if isinstance(value, list) and len(value) > 0:
value = maybe_convert_platform(value)
else:
value = com.asarray_tuplesafe(value)
elif value.ndim == 2:
value = value.copy().T
elif isinstance(value, Index):
value = value.copy(deep=True)
else:
value = value.copy()
# possibly infer to datetimelike
if is_object_dtype(value.dtype):
value = maybe_infer_to_datetimelike(value)
else:
# cast ignores pandas dtypes. so save the dtype first
infer_dtype, _ = infer_dtype_from_scalar(value, pandas_dtype=True)
# upcast
value = cast_scalar_to_array(len(self.index), value)
value = maybe_cast_to_datetime(value, infer_dtype)
# return internal types directly
if is_extension_array_dtype(value):
return value
# broadcast across multiple columns if necessary
if broadcast and key in self.columns and value.ndim == 1:
if not self.columns.is_unique or isinstance(self.columns, ABCMultiIndex):
existing_piece = self[key]
if isinstance(existing_piece, DataFrame):
value = np.tile(value, (len(existing_piece.columns), 1))
return np.atleast_2d(np.asarray(value))
@property
def _series(self):
return {
item: Series(self._data.iget(idx), index=self.index, name=item)
for idx, item in enumerate(self.columns)
}
def lookup(self, row_labels, col_labels) -> np.ndarray:
"""
Label-based "fancy indexing" function for DataFrame.
Given equal-length arrays of row and column labels, return an
array of the values corresponding to each (row, col) pair.
Parameters
----------
row_labels : sequence
The row labels to use for lookup.
col_labels : sequence
The column labels to use for lookup.
Returns
-------
numpy.ndarray
The found values.
"""
n = len(row_labels)
if n != len(col_labels):
raise ValueError("Row labels must have same size as column labels")
thresh = 1000
if not self._is_mixed_type or n > thresh:
values = self.values
ridx = self.index.get_indexer(row_labels)
cidx = self.columns.get_indexer(col_labels)
if (ridx == -1).any():
raise KeyError("One or more row labels was not found")
if (cidx == -1).any():
raise KeyError("One or more column labels was not found")
flat_index = ridx * len(self.columns) + cidx
result = values.flat[flat_index]
else:
result = np.empty(n, dtype="O")
for i, (r, c) in enumerate(zip(row_labels, col_labels)):
result[i] = self._get_value(r, c)
if is_object_dtype(result):
result = lib.maybe_convert_objects(result)
return result
# ----------------------------------------------------------------------
# Reindexing and alignment
def _reindex_axes(self, axes, level, limit, tolerance, method, fill_value, copy):
frame = self
columns = axes["columns"]
if columns is not None:
frame = frame._reindex_columns(
columns, method, copy, level, fill_value, limit, tolerance
)
index = axes["index"]
if index is not None:
frame = frame._reindex_index(
index, method, copy, level, fill_value, limit, tolerance
)
return frame
def _reindex_index(
self,
new_index,
method,
copy,
level,
fill_value=np.nan,
limit=None,
tolerance=None,
):
new_index, indexer = self.index.reindex(
new_index, method=method, level=level, limit=limit, tolerance=tolerance
)
return self._reindex_with_indexers(
{0: [new_index, indexer]},
copy=copy,
fill_value=fill_value,
allow_dups=False,
)
def _reindex_columns(
self,
new_columns,
method,
copy,
level,
fill_value=None,
limit=None,
tolerance=None,
):
new_columns, indexer = self.columns.reindex(
new_columns, method=method, level=level, limit=limit, tolerance=tolerance
)
return self._reindex_with_indexers(
{1: [new_columns, indexer]},
copy=copy,
fill_value=fill_value,
allow_dups=False,
)
def _reindex_multi(self, axes, copy, fill_value) -> "DataFrame":
"""
We are guaranteed non-Nones in the axes.
"""
new_index, row_indexer = self.index.reindex(axes["index"])
new_columns, col_indexer = self.columns.reindex(axes["columns"])
if row_indexer is not None and col_indexer is not None:
indexer = row_indexer, col_indexer
new_values = algorithms.take_2d_multi(
self.values, indexer, fill_value=fill_value
)
return self._constructor(new_values, index=new_index, columns=new_columns)
else:
return self._reindex_with_indexers(
{0: [new_index, row_indexer], 1: [new_columns, col_indexer]},
copy=copy,
fill_value=fill_value,
)
@Appender(_shared_docs["align"] % _shared_doc_kwargs)
def align(
self,
other,
join="outer",
axis=None,
level=None,
copy=True,
fill_value=None,
method=None,
limit=None,
fill_axis=0,
broadcast_axis=None,
) -> "DataFrame":
return super().align(
other,
join=join,
axis=axis,
level=level,
copy=copy,
fill_value=fill_value,
method=method,
limit=limit,
fill_axis=fill_axis,
broadcast_axis=broadcast_axis,
)
@Appender(
"""
Examples
--------
>>> df = pd.DataFrame({"A": [1, 2, 3], "B": [4, 5, 6]})
Change the row labels.
>>> df.set_axis(['a', 'b', 'c'], axis='index')
A B
a 1 4
b 2 5
c 3 6
Change the column labels.
>>> df.set_axis(['I', 'II'], axis='columns')
I II
0 1 4
1 2 5
2 3 6
Now, update the labels inplace.
>>> df.set_axis(['i', 'ii'], axis='columns', inplace=True)
>>> df
i ii
0 1 4
1 2 5
2 3 6
"""
)
@Substitution(
**_shared_doc_kwargs,
extended_summary_sub=" column or",
axis_description_sub=", and 1 identifies the columns",
see_also_sub=" or columns",
)
@Appender(NDFrame.set_axis.__doc__)
def set_axis(self, labels, axis: Axis = 0, inplace: bool = False):
return super().set_axis(labels, axis=axis, inplace=inplace)
@Substitution(**_shared_doc_kwargs)
@Appender(NDFrame.reindex.__doc__)
@rewrite_axis_style_signature(
"labels",
[
("method", None),
("copy", True),
("level", None),
("fill_value", np.nan),
("limit", None),
("tolerance", None),
],
)
def reindex(self, *args, **kwargs) -> "DataFrame":
axes = validate_axis_style_args(self, args, kwargs, "labels", "reindex")
kwargs.update(axes)
# Pop these, since the values are in `kwargs` under different names
kwargs.pop("axis", None)
kwargs.pop("labels", None)
return super().reindex(**kwargs)
def drop(
self,
labels=None,
axis=0,
index=None,
columns=None,
level=None,
inplace=False,
errors="raise",
):
"""
Drop specified labels from rows or columns.
Remove rows or columns by specifying label names and corresponding
axis, or by specifying directly index or column names. When using a
multi-index, labels on different levels can be removed by specifying
the level.
Parameters
----------
labels : single label or list-like
Index or column labels to drop.
axis : {0 or 'index', 1 or 'columns'}, default 0
Whether to drop labels from the index (0 or 'index') or
columns (1 or 'columns').
index : single label or list-like
Alternative to specifying axis (``labels, axis=0``
is equivalent to ``index=labels``).
.. versionadded:: 0.21.0
columns : single label or list-like
Alternative to specifying axis (``labels, axis=1``
is equivalent to ``columns=labels``).
.. versionadded:: 0.21.0
level : int or level name, optional
For MultiIndex, level from which the labels will be removed.
inplace : bool, default False
If True, do operation inplace and return None.
errors : {'ignore', 'raise'}, default 'raise'
If 'ignore', suppress error and only existing labels are
dropped.
Returns
-------
DataFrame
DataFrame without the removed index or column labels.
Raises
------
KeyError
If any of the labels is not found in the selected axis.
See Also
--------
DataFrame.loc : Label-location based indexer for selection by label.
DataFrame.dropna : Return DataFrame with labels on given axis omitted
where (all or any) data are missing.
DataFrame.drop_duplicates : Return DataFrame with duplicate rows
removed, optionally only considering certain columns.
Series.drop : Return Series with specified index labels removed.
Examples
--------
>>> df = pd.DataFrame(np.arange(12).reshape(3, 4),
... columns=['A', 'B', 'C', 'D'])
>>> df
A B C D
0 0 1 2 3
1 4 5 6 7
2 8 9 10 11
Drop columns
>>> df.drop(['B', 'C'], axis=1)
A D
0 0 3
1 4 7
2 8 11
>>> df.drop(columns=['B', 'C'])
A D
0 0 3
1 4 7
2 8 11
Drop a row by index
>>> df.drop([0, 1])
A B C D
2 8 9 10 11
Drop columns and/or rows of MultiIndex DataFrame
>>> midx = pd.MultiIndex(levels=[['lama', 'cow', 'falcon'],
... ['speed', 'weight', 'length']],
... codes=[[0, 0, 0, 1, 1, 1, 2, 2, 2],
... [0, 1, 2, 0, 1, 2, 0, 1, 2]])
>>> df = pd.DataFrame(index=midx, columns=['big', 'small'],
... data=[[45, 30], [200, 100], [1.5, 1], [30, 20],
... [250, 150], [1.5, 0.8], [320, 250],
... [1, 0.8], [0.3, 0.2]])
>>> df
big small
lama speed 45.0 30.0
weight 200.0 100.0
length 1.5 1.0
cow speed 30.0 20.0
weight 250.0 150.0
length 1.5 0.8
falcon speed 320.0 250.0
weight 1.0 0.8
length 0.3 0.2
>>> df.drop(index='cow', columns='small')
big
lama speed 45.0
weight 200.0
length 1.5
falcon speed 320.0
weight 1.0
length 0.3
>>> df.drop(index='length', level=1)
big small
lama speed 45.0 30.0
weight 200.0 100.0
cow speed 30.0 20.0
weight 250.0 150.0
falcon speed 320.0 250.0
weight 1.0 0.8
"""
return super().drop(
labels=labels,
axis=axis,
index=index,
columns=columns,
level=level,
inplace=inplace,
errors=errors,
)
@rewrite_axis_style_signature(
"mapper",
[("copy", True), ("inplace", False), ("level", None), ("errors", "ignore")],
)
def rename(
self,
mapper: Optional[Renamer] = None,
*,
index: Optional[Renamer] = None,
columns: Optional[Renamer] = None,
axis: Optional[Axis] = None,
copy: bool = True,
inplace: bool = False,
level: Optional[Level] = None,
errors: str = "ignore",
) -> Optional["DataFrame"]:
"""
Alter axes labels.
Function / dict values must be unique (1-to-1). Labels not contained in
a dict / Series will be left as-is. Extra labels listed don't throw an
error.
See the :ref:`user guide <basics.rename>` for more.
Parameters
----------
mapper : dict-like or function
Dict-like or functions transformations to apply to
that axis' values. Use either ``mapper`` and ``axis`` to
specify the axis to target with ``mapper``, or ``index`` and
``columns``.
index : dict-like or function
Alternative to specifying axis (``mapper, axis=0``
is equivalent to ``index=mapper``).
columns : dict-like or function
Alternative to specifying axis (``mapper, axis=1``
is equivalent to ``columns=mapper``).
axis : int or str
Axis to target with ``mapper``. Can be either the axis name
('index', 'columns') or number (0, 1). The default is 'index'.
copy : bool, default True
Also copy underlying data.
inplace : bool, default False
Whether to return a new DataFrame. If True then value of copy is
ignored.
level : int or level name, default None
In case of a MultiIndex, only rename labels in the specified
level.
errors : {'ignore', 'raise'}, default 'ignore'
If 'raise', raise a `KeyError` when a dict-like `mapper`, `index`,
or `columns` contains labels that are not present in the Index
being transformed.
If 'ignore', existing keys will be renamed and extra keys will be
ignored.
Returns
-------
DataFrame
DataFrame with the renamed axis labels.
Raises
------
KeyError
If any of the labels is not found in the selected axis and
"errors='raise'".
See Also
--------
DataFrame.rename_axis : Set the name of the axis.
Examples
--------
``DataFrame.rename`` supports two calling conventions
* ``(index=index_mapper, columns=columns_mapper, ...)``
* ``(mapper, axis={'index', 'columns'}, ...)``
We *highly* recommend using keyword arguments to clarify your
intent.
Rename columns using a mapping:
>>> df = pd.DataFrame({"A": [1, 2, 3], "B": [4, 5, 6]})
>>> df.rename(columns={"A": "a", "B": "c"})
a c
0 1 4
1 2 5
2 3 6
Rename index using a mapping:
>>> df.rename(index={0: "x", 1: "y", 2: "z"})
A B
x 1 4
y 2 5
z 3 6
Cast index labels to a different type:
>>> df.index
RangeIndex(start=0, stop=3, step=1)
>>> df.rename(index=str).index
Index(['0', '1', '2'], dtype='object')
>>> df.rename(columns={"A": "a", "B": "b", "C": "c"}, errors="raise")
Traceback (most recent call last):
KeyError: ['C'] not found in axis
Using axis-style parameters
>>> df.rename(str.lower, axis='columns')
a b
0 1 4
1 2 5
2 3 6
>>> df.rename({1: 2, 2: 4}, axis='index')
A B
0 1 4
2 2 5
4 3 6
"""
return super().rename(
mapper=mapper,
index=index,
columns=columns,
axis=axis,
copy=copy,
inplace=inplace,
level=level,
errors=errors,
)
@doc(NDFrame.fillna, **_shared_doc_kwargs)
def fillna(
self,
value=None,
method=None,
axis=None,
inplace=False,
limit=None,
downcast=None,
) -> Optional["DataFrame"]:
return super().fillna(
value=value,
method=method,
axis=axis,
inplace=inplace,
limit=limit,
downcast=downcast,
)
@Appender(_shared_docs["replace"] % _shared_doc_kwargs)
def replace(
self,
to_replace=None,
value=None,
inplace=False,
limit=None,
regex=False,
method="pad",
):
return super().replace(
to_replace=to_replace,
value=value,
inplace=inplace,
limit=limit,
regex=regex,
method=method,
)
@Appender(_shared_docs["shift"] % _shared_doc_kwargs)
def shift(self, periods=1, freq=None, axis=0, fill_value=None) -> "DataFrame":
return super().shift(
periods=periods, freq=freq, axis=axis, fill_value=fill_value
)
def set_index(
self, keys, drop=True, append=False, inplace=False, verify_integrity=False
):
"""
Set the DataFrame index using existing columns.
Set the DataFrame index (row labels) using one or more existing
columns or arrays (of the correct length). The index can replace the
existing index or expand on it.
Parameters
----------
keys : label or array-like or list of labels/arrays
This parameter can be either a single column key, a single array of
the same length as the calling DataFrame, or a list containing an
arbitrary combination of column keys and arrays. Here, "array"
encompasses :class:`Series`, :class:`Index`, ``np.ndarray``, and
instances of :class:`~collections.abc.Iterator`.
drop : bool, default True
Delete columns to be used as the new index.
append : bool, default False
Whether to append columns to existing index.
inplace : bool, default False
Modify the DataFrame in place (do not create a new object).
verify_integrity : bool, default False
Check the new index for duplicates. Otherwise defer the check until
necessary. Setting to False will improve the performance of this
method.
Returns
-------
DataFrame
Changed row labels.
See Also
--------
DataFrame.reset_index : Opposite of set_index.
DataFrame.reindex : Change to new indices or expand indices.
DataFrame.reindex_like : Change to same indices as other DataFrame.
Examples
--------
>>> df = pd.DataFrame({'month': [1, 4, 7, 10],
... 'year': [2012, 2014, 2013, 2014],
... 'sale': [55, 40, 84, 31]})
>>> df
month year sale
0 1 2012 55
1 4 2014 40
2 7 2013 84
3 10 2014 31
Set the index to become the 'month' column:
>>> df.set_index('month')
year sale
month
1 2012 55
4 2014 40
7 2013 84
10 2014 31
Create a MultiIndex using columns 'year' and 'month':
>>> df.set_index(['year', 'month'])
sale
year month
2012 1 55
2014 4 40
2013 7 84
2014 10 31
Create a MultiIndex using an Index and a column:
>>> df.set_index([pd.Index([1, 2, 3, 4]), 'year'])
month sale
year
1 2012 1 55
2 2014 4 40
3 2013 7 84
4 2014 10 31
Create a MultiIndex using two Series:
>>> s = pd.Series([1, 2, 3, 4])
>>> df.set_index([s, s**2])
month year sale
1 1 1 2012 55
2 4 4 2014 40
3 9 7 2013 84
4 16 10 2014 31
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not isinstance(keys, list):
keys = [keys]
err_msg = (
'The parameter "keys" may be a column key, one-dimensional '
"array, or a list containing only valid column keys and "
"one-dimensional arrays."
)
missing: List[Label] = []
for col in keys:
if isinstance(
col, (ABCIndexClass, ABCSeries, np.ndarray, list, abc.Iterator)
):
# arrays are fine as long as they are one-dimensional
# iterators get converted to list below
if getattr(col, "ndim", 1) != 1:
raise ValueError(err_msg)
else:
# everything else gets tried as a key; see GH 24969
try:
found = col in self.columns
except TypeError as err:
raise TypeError(
f"{err_msg}. Received column of type {type(col)}"
) from err
else:
if not found:
missing.append(col)
if missing:
raise KeyError(f"None of {missing} are in the columns")
if inplace:
frame = self
else:
frame = self.copy()
arrays = []
names = []
if append:
names = list(self.index.names)
if isinstance(self.index, ABCMultiIndex):
for i in range(self.index.nlevels):
arrays.append(self.index._get_level_values(i))
else:
arrays.append(self.index)
to_remove: List[Label] = []
for col in keys:
if isinstance(col, ABCMultiIndex):
for n in range(col.nlevels):
arrays.append(col._get_level_values(n))
names.extend(col.names)
elif isinstance(col, (ABCIndexClass, ABCSeries)):
# if Index then not MultiIndex (treated above)
arrays.append(col)
names.append(col.name)
elif isinstance(col, (list, np.ndarray)):
arrays.append(col)
names.append(None)
elif isinstance(col, abc.Iterator):
arrays.append(list(col))
names.append(None)
# from here, col can only be a column label
else:
arrays.append(frame[col]._values)
names.append(col)
if drop:
to_remove.append(col)
if len(arrays[-1]) != len(self):
# check newest element against length of calling frame, since
# ensure_index_from_sequences would not raise for append=False.
raise ValueError(
f"Length mismatch: Expected {len(self)} rows, "
f"received array of length {len(arrays[-1])}"
)
index = ensure_index_from_sequences(arrays, names)
if verify_integrity and not index.is_unique:
duplicates = index[index.duplicated()].unique()
raise ValueError(f"Index has duplicate keys: {duplicates}")
# use set to handle duplicate column names gracefully in case of drop
for c in set(to_remove):
del frame[c]
# clear up memory usage
index._cleanup()
frame.index = index
if not inplace:
return frame
def reset_index(
self,
level: Optional[Union[Hashable, Sequence[Hashable]]] = None,
drop: bool = False,
inplace: bool = False,
col_level: Hashable = 0,
col_fill: Label = "",
) -> Optional["DataFrame"]:
"""
Reset the index, or a level of it.
Reset the index of the DataFrame, and use the default one instead.
If the DataFrame has a MultiIndex, this method can remove one or more
levels.
Parameters
----------
level : int, str, tuple, or list, default None
Only remove the given levels from the index. Removes all levels by
default.
drop : bool, default False
Do not try to insert index into dataframe columns. This resets
the index to the default integer index.
inplace : bool, default False
Modify the DataFrame in place (do not create a new object).
col_level : int or str, default 0
If the columns have multiple levels, determines which level the
labels are inserted into. By default it is inserted into the first
level.
col_fill : object, default ''
If the columns have multiple levels, determines how the other
levels are named. If None then the index name is repeated.
Returns
-------
DataFrame or None
DataFrame with the new index or None if ``inplace=True``.
See Also
--------
DataFrame.set_index : Opposite of reset_index.
DataFrame.reindex : Change to new indices or expand indices.
DataFrame.reindex_like : Change to same indices as other DataFrame.
Examples
--------
>>> df = pd.DataFrame([('bird', 389.0),
... ('bird', 24.0),
... ('mammal', 80.5),
... ('mammal', np.nan)],
... index=['falcon', 'parrot', 'lion', 'monkey'],
... columns=('class', 'max_speed'))
>>> df
class max_speed
falcon bird 389.0
parrot bird 24.0
lion mammal 80.5
monkey mammal NaN
When we reset the index, the old index is added as a column, and a
new sequential index is used:
>>> df.reset_index()
index class max_speed
0 falcon bird 389.0
1 parrot bird 24.0
2 lion mammal 80.5
3 monkey mammal NaN
We can use the `drop` parameter to avoid the old index being added as
a column:
>>> df.reset_index(drop=True)
class max_speed
0 bird 389.0
1 bird 24.0
2 mammal 80.5
3 mammal NaN
You can also use `reset_index` with `MultiIndex`.
>>> index = pd.MultiIndex.from_tuples([('bird', 'falcon'),
... ('bird', 'parrot'),
... ('mammal', 'lion'),
... ('mammal', 'monkey')],
... names=['class', 'name'])
>>> columns = pd.MultiIndex.from_tuples([('speed', 'max'),
... ('species', 'type')])
>>> df = pd.DataFrame([(389.0, 'fly'),
... ( 24.0, 'fly'),
... ( 80.5, 'run'),
... (np.nan, 'jump')],
... index=index,
... columns=columns)
>>> df
speed species
max type
class name
bird falcon 389.0 fly
parrot 24.0 fly
mammal lion 80.5 run
monkey NaN jump
If the index has multiple levels, we can reset a subset of them:
>>> df.reset_index(level='class')
class speed species
max type
name
falcon bird 389.0 fly
parrot bird 24.0 fly
lion mammal 80.5 run
monkey mammal NaN jump
If we are not dropping the index, by default, it is placed in the top
level. We can place it in another level:
>>> df.reset_index(level='class', col_level=1)
speed species
class max type
name
falcon bird 389.0 fly
parrot bird 24.0 fly
lion mammal 80.5 run
monkey mammal NaN jump
When the index is inserted under another level, we can specify under
which one with the parameter `col_fill`:
>>> df.reset_index(level='class', col_level=1, col_fill='species')
species speed species
class max type
name
falcon bird 389.0 fly
parrot bird 24.0 fly
lion mammal 80.5 run
monkey mammal NaN jump
If we specify a nonexistent level for `col_fill`, it is created:
>>> df.reset_index(level='class', col_level=1, col_fill='genus')
genus speed species
class max type
name
falcon bird 389.0 fly
parrot bird 24.0 fly
lion mammal 80.5 run
monkey mammal NaN jump
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if inplace:
new_obj = self
else:
new_obj = self.copy()
def _maybe_casted_values(index, labels=None):
values = index._values
if not isinstance(index, (PeriodIndex, DatetimeIndex)):
if values.dtype == np.object_:
values = lib.maybe_convert_objects(values)
# if we have the labels, extract the values with a mask
if labels is not None:
mask = labels == -1
# we can have situations where the whole mask is -1,
# meaning there is nothing found in labels, so make all nan's
if mask.all():
values = np.empty(len(mask))
values.fill(np.nan)
else:
values = values.take(labels)
# TODO(https://github.com/pandas-dev/pandas/issues/24206)
# Push this into maybe_upcast_putmask?
# We can't pass EAs there right now. Looks a bit
# complicated.
# So we unbox the ndarray_values, op, re-box.
values_type = type(values)
values_dtype = values.dtype
if issubclass(values_type, DatetimeLikeArray):
values = values._data
if mask.any():
values, _ = maybe_upcast_putmask(values, mask, np.nan)
if issubclass(values_type, DatetimeLikeArray):
values = values_type(values, dtype=values_dtype)
return values
new_index = ibase.default_index(len(new_obj))
if level is not None:
if not isinstance(level, (tuple, list)):
level = [level]
level = [self.index._get_level_number(lev) for lev in level]
if len(level) < self.index.nlevels:
new_index = self.index.droplevel(level)
if not drop:
to_insert: Iterable[Tuple[Any, Optional[Any]]]
if isinstance(self.index, ABCMultiIndex):
names = [
(n if n is not None else f"level_{i}")
for i, n in enumerate(self.index.names)
]
to_insert = zip(self.index.levels, self.index.codes)
else:
default = "index" if "index" not in self else "level_0"
names = [default] if self.index.name is None else [self.index.name]
to_insert = ((self.index, None),)
multi_col = isinstance(self.columns, ABCMultiIndex)
for i, (lev, lab) in reversed(list(enumerate(to_insert))):
if not (level is None or i in level):
continue
name = names[i]
if multi_col:
col_name = list(name) if isinstance(name, tuple) else [name]
if col_fill is None:
if len(col_name) not in (1, self.columns.nlevels):
raise ValueError(
"col_fill=None is incompatible "
f"with incomplete column name {name}"
)
col_fill = col_name[0]
lev_num = self.columns._get_level_number(col_level)
name_lst = [col_fill] * lev_num + col_name
missing = self.columns.nlevels - len(name_lst)
name_lst += [col_fill] * missing
name = tuple(name_lst)
# to ndarray and maybe infer different dtype
level_values = _maybe_casted_values(lev, lab)
new_obj.insert(0, name, level_values)
new_obj.index = new_index
if not inplace:
return new_obj
return None
# ----------------------------------------------------------------------
# Reindex-based selection methods
@Appender(_shared_docs["isna"] % _shared_doc_kwargs)
def isna(self) -> "DataFrame":
return super().isna()
@Appender(_shared_docs["isna"] % _shared_doc_kwargs)
def isnull(self) -> "DataFrame":
return super().isnull()
@Appender(_shared_docs["notna"] % _shared_doc_kwargs)
def notna(self) -> "DataFrame":
return super().notna()
@Appender(_shared_docs["notna"] % _shared_doc_kwargs)
def notnull(self) -> "DataFrame":
return super().notnull()
def dropna(self, axis=0, how="any", thresh=None, subset=None, inplace=False):
"""
Remove missing values.
See the :ref:`User Guide <missing_data>` for more on which values are
considered missing, and how to work with missing data.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
Determine if rows or columns which contain missing values are
removed.
* 0, or 'index' : Drop rows which contain missing values.
* 1, or 'columns' : Drop columns which contain missing value.
.. versionchanged:: 1.0.0
Pass tuple or list to drop on multiple axes.
Only a single axis is allowed.
how : {'any', 'all'}, default 'any'
Determine if row or column is removed from DataFrame, when we have
at least one NA or all NA.
* 'any' : If any NA values are present, drop that row or column.
* 'all' : If all values are NA, drop that row or column.
thresh : int, optional
Require that many non-NA values.
subset : array-like, optional
Labels along other axis to consider, e.g. if you are dropping rows
these would be a list of columns to include.
inplace : bool, default False
If True, do operation inplace and return None.
Returns
-------
DataFrame
DataFrame with NA entries dropped from it.
See Also
--------
DataFrame.isna: Indicate missing values.
DataFrame.notna : Indicate existing (non-missing) values.
DataFrame.fillna : Replace missing values.
Series.dropna : Drop missing values.
Index.dropna : Drop missing indices.
Examples
--------
>>> df = pd.DataFrame({"name": ['Alfred', 'Batman', 'Catwoman'],
... "toy": [np.nan, 'Batmobile', 'Bullwhip'],
... "born": [pd.NaT, pd.Timestamp("1940-04-25"),
... pd.NaT]})
>>> df
name toy born
0 Alfred NaN NaT
1 Batman Batmobile 1940-04-25
2 Catwoman Bullwhip NaT
Drop the rows where at least one element is missing.
>>> df.dropna()
name toy born
1 Batman Batmobile 1940-04-25
Drop the columns where at least one element is missing.
>>> df.dropna(axis='columns')
name
0 Alfred
1 Batman
2 Catwoman
Drop the rows where all elements are missing.
>>> df.dropna(how='all')
name toy born
0 Alfred NaN NaT
1 Batman Batmobile 1940-04-25
2 Catwoman Bullwhip NaT
Keep only the rows with at least 2 non-NA values.
>>> df.dropna(thresh=2)
name toy born
1 Batman Batmobile 1940-04-25
2 Catwoman Bullwhip NaT
Define in which columns to look for missing values.
>>> df.dropna(subset=['name', 'born'])
name toy born
1 Batman Batmobile 1940-04-25
Keep the DataFrame with valid entries in the same variable.
>>> df.dropna(inplace=True)
>>> df
name toy born
1 Batman Batmobile 1940-04-25
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if isinstance(axis, (tuple, list)):
# GH20987
raise TypeError("supplying multiple axes to axis is no longer supported.")
axis = self._get_axis_number(axis)
agg_axis = 1 - axis
agg_obj = self
if subset is not None:
ax = self._get_axis(agg_axis)
indices = ax.get_indexer_for(subset)
check = indices == -1
if check.any():
raise KeyError(list(np.compress(check, subset)))
agg_obj = self.take(indices, axis=agg_axis)
count = agg_obj.count(axis=agg_axis)
if thresh is not None:
mask = count >= thresh
elif how == "any":
mask = count == len(agg_obj._get_axis(agg_axis))
elif how == "all":
mask = count > 0
else:
if how is not None:
raise ValueError(f"invalid how option: {how}")
else:
raise TypeError("must specify how or thresh")
result = self.loc(axis=axis)[mask]
if inplace:
self._update_inplace(result)
else:
return result
def drop_duplicates(
self,
subset: Optional[Union[Hashable, Sequence[Hashable]]] = None,
keep: Union[str, bool] = "first",
inplace: bool = False,
ignore_index: bool = False,
) -> Optional["DataFrame"]:
"""
Return DataFrame with duplicate rows removed.
Considering certain columns is optional. Indexes, including time indexes
are ignored.
Parameters
----------
subset : column label or sequence of labels, optional
Only consider certain columns for identifying duplicates, by
default use all of the columns.
keep : {'first', 'last', False}, default 'first'
Determines which duplicates (if any) to keep.
- ``first`` : Drop duplicates except for the first occurrence.
- ``last`` : Drop duplicates except for the last occurrence.
- False : Drop all duplicates.
inplace : bool, default False
Whether to drop duplicates in place or to return a copy.
ignore_index : bool, default False
If True, the resulting axis will be labeled 0, 1, …, n - 1.
.. versionadded:: 1.0.0
Returns
-------
DataFrame
DataFrame with duplicates removed or None if ``inplace=True``.
See Also
--------
DataFrame.value_counts: Count unique combinations of columns.
"""
if self.empty:
return self.copy()
inplace = validate_bool_kwarg(inplace, "inplace")
duplicated = self.duplicated(subset, keep=keep)
if inplace:
(inds,) = np.asarray(-duplicated).nonzero()
new_data = self._data.take(inds)
if ignore_index:
new_data.axes[1] = ibase.default_index(len(inds))
self._update_inplace(new_data)
else:
result = self[-duplicated]
if ignore_index:
result.index = ibase.default_index(len(result))
return result
return None
def duplicated(
self,
subset: Optional[Union[Hashable, Sequence[Hashable]]] = None,
keep: Union[str, bool] = "first",
) -> "Series":
"""
Return boolean Series denoting duplicate rows.
Considering certain columns is optional.
Parameters
----------
subset : column label or sequence of labels, optional
Only consider certain columns for identifying duplicates, by
default use all of the columns.
keep : {'first', 'last', False}, default 'first'
Determines which duplicates (if any) to mark.
- ``first`` : Mark duplicates as ``True`` except for the first occurrence.
- ``last`` : Mark duplicates as ``True`` except for the last occurrence.
- False : Mark all duplicates as ``True``.
Returns
-------
Series
"""
from pandas.core.sorting import get_group_index
from pandas._libs.hashtable import duplicated_int64, _SIZE_HINT_LIMIT
if self.empty:
return Series(dtype=bool)
def f(vals):
labels, shape = algorithms.factorize(
vals, size_hint=min(len(self), _SIZE_HINT_LIMIT)
)
return labels.astype("i8", copy=False), len(shape)
if subset is None:
subset = self.columns
elif (
not np.iterable(subset)
or isinstance(subset, str)
or isinstance(subset, tuple)
and subset in self.columns
):
subset = (subset,)
# needed for mypy since can't narrow types using np.iterable
subset = cast(Iterable, subset)
# Verify all columns in subset exist in the queried dataframe
# Otherwise, raise a KeyError, same as if you try to __getitem__ with a
# key that doesn't exist.
diff = Index(subset).difference(self.columns)
if not diff.empty:
raise KeyError(diff)
vals = (col.values for name, col in self.items() if name in subset)
labels, shape = map(list, zip(*map(f, vals)))
ids = get_group_index(labels, shape, sort=False, xnull=False)
return Series(duplicated_int64(ids, keep), index=self.index)
# ----------------------------------------------------------------------
# Sorting
@Substitution(**_shared_doc_kwargs)
@Appender(NDFrame.sort_values.__doc__)
def sort_values(
self,
by,
axis=0,
ascending=True,
inplace=False,
kind="quicksort",
na_position="last",
ignore_index=False,
):
inplace = validate_bool_kwarg(inplace, "inplace")
axis = self._get_axis_number(axis)
if not isinstance(by, list):
by = [by]
if is_sequence(ascending) and len(by) != len(ascending):
raise ValueError(
f"Length of ascending ({len(ascending)}) != length of by ({len(by)})"
)
if len(by) > 1:
from pandas.core.sorting import lexsort_indexer
keys = [self._get_label_or_level_values(x, axis=axis) for x in by]
indexer = lexsort_indexer(keys, orders=ascending, na_position=na_position)
indexer = ensure_platform_int(indexer)
else:
from pandas.core.sorting import nargsort
by = by[0]
k = self._get_label_or_level_values(by, axis=axis)
if isinstance(ascending, (tuple, list)):
ascending = ascending[0]
indexer = nargsort(
k, kind=kind, ascending=ascending, na_position=na_position
)
new_data = self._data.take(
indexer, axis=self._get_block_manager_axis(axis), verify=False
)
if ignore_index:
new_data.axes[1] = ibase.default_index(len(indexer))
if inplace:
return self._update_inplace(new_data)
else:
return self._constructor(new_data).__finalize__(self)
def sort_index(
self,
axis=0,
level=None,
ascending: bool = True,
inplace: bool = False,
kind: str = "quicksort",
na_position: str = "last",
sort_remaining: bool = True,
ignore_index: bool = False,
):
"""
Sort object by labels (along an axis).
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis along which to sort. The value 0 identifies the rows,
and 1 identifies the columns.
level : int or level name or list of ints or list of level names
If not None, sort on values in specified index level(s).
ascending : bool or list of bools, default True
Sort ascending vs. descending. When the index is a MultiIndex the
sort direction can be controlled for each level individually.
inplace : bool, default False
If True, perform operation in-place.
kind : {'quicksort', 'mergesort', 'heapsort'}, default 'quicksort'
Choice of sorting algorithm. See also ndarray.np.sort for more
information. `mergesort` is the only stable algorithm. For
DataFrames, this option is only applied when sorting on a single
column or label.
na_position : {'first', 'last'}, default 'last'
Puts NaNs at the beginning if `first`; `last` puts NaNs at the end.
Not implemented for MultiIndex.
sort_remaining : bool, default True
If True and sorting by level and index is multilevel, sort by other
levels too (in order) after sorting by specified level.
ignore_index : bool, default False
If True, the resulting axis will be labeled 0, 1, …, n - 1.
.. versionadded:: 1.0.0
Returns
-------
sorted_obj : DataFrame or None
DataFrame with sorted index if inplace=False, None otherwise.
"""
# TODO: this can be combined with Series.sort_index impl as
# almost identical
inplace = validate_bool_kwarg(inplace, "inplace")
axis = self._get_axis_number(axis)
labels = self._get_axis(axis)
# make sure that the axis is lexsorted to start
# if not we need to reconstruct to get the correct indexer
labels = labels._sort_levels_monotonic()
if level is not None:
new_axis, indexer = labels.sortlevel(
level, ascending=ascending, sort_remaining=sort_remaining
)
elif isinstance(labels, ABCMultiIndex):
from pandas.core.sorting import lexsort_indexer
indexer = lexsort_indexer(
labels._get_codes_for_sorting(),
orders=ascending,
na_position=na_position,
)
else:
from pandas.core.sorting import nargsort
# Check monotonic-ness before sort an index
# GH11080
if (ascending and labels.is_monotonic_increasing) or (
not ascending and labels.is_monotonic_decreasing
):
if inplace:
return
else:
return self.copy()
indexer = nargsort(
labels, kind=kind, ascending=ascending, na_position=na_position
)
baxis = self._get_block_manager_axis(axis)
new_data = self._data.take(indexer, axis=baxis, verify=False)
# reconstruct axis if needed
new_data.axes[baxis] = new_data.axes[baxis]._sort_levels_monotonic()
if ignore_index:
new_data.axes[1] = ibase.default_index(len(indexer))
if inplace:
return self._update_inplace(new_data)
else:
return self._constructor(new_data).__finalize__(self)
def value_counts(
self,
subset: Optional[Sequence[Label]] = None,
normalize: bool = False,
sort: bool = True,
ascending: bool = False,
):
"""
Return a Series containing counts of unique rows in the DataFrame.
.. versionadded:: 1.1.0
Parameters
----------
subset : list-like, optional
Columns to use when counting unique combinations.
normalize : bool, default False
Return proportions rather than frequencies.
sort : bool, default True
Sort by frequencies.
ascending : bool, default False
Sort in ascending order.
Returns
-------
Series
See Also
--------
Series.value_counts: Equivalent method on Series.
Notes
-----
The returned Series will have a MultiIndex with one level per input
column. By default, rows that contain any NA values are omitted from
the result. By default, the resulting Series will be in descending
order so that the first element is the most frequently-occurring row.
Examples
--------
>>> df = pd.DataFrame({'num_legs': [2, 4, 4, 6],
... 'num_wings': [2, 0, 0, 0]},
... index=['falcon', 'dog', 'cat', 'ant'])
>>> df
num_legs num_wings
falcon 2 2
dog 4 0
cat 4 0
ant 6 0
>>> df.value_counts()
num_legs num_wings
4 0 2
6 0 1
2 2 1
dtype: int64
>>> df.value_counts(sort=False)
num_legs num_wings
2 2 1
4 0 2
6 0 1
dtype: int64
>>> df.value_counts(ascending=True)
num_legs num_wings
2 2 1
6 0 1
4 0 2
dtype: int64
>>> df.value_counts(normalize=True)
num_legs num_wings
4 0 0.50
6 0 0.25
2 2 0.25
dtype: float64
"""
if subset is None:
subset = self.columns.tolist()
counts = self.groupby(subset).size()
if sort:
counts = counts.sort_values(ascending=ascending)
if normalize:
counts /= counts.sum()
# Force MultiIndex for single column
if len(subset) == 1:
counts.index = MultiIndex.from_arrays(
[counts.index], names=[counts.index.name]
)
return counts
def nlargest(self, n, columns, keep="first") -> "DataFrame":
"""
Return the first `n` rows ordered by `columns` in descending order.
Return the first `n` rows with the largest values in `columns`, in
descending order. The columns that are not specified are returned as
well, but not used for ordering.
This method is equivalent to
``df.sort_values(columns, ascending=False).head(n)``, but more
performant.
Parameters
----------
n : int
Number of rows to return.
columns : label or list of labels
Column label(s) to order by.
keep : {'first', 'last', 'all'}, default 'first'
Where there are duplicate values:
- `first` : prioritize the first occurrence(s)
- `last` : prioritize the last occurrence(s)
- ``all`` : do not drop any duplicates, even it means
selecting more than `n` items.
.. versionadded:: 0.24.0
Returns
-------
DataFrame
The first `n` rows ordered by the given columns in descending
order.
See Also
--------
DataFrame.nsmallest : Return the first `n` rows ordered by `columns` in
ascending order.
DataFrame.sort_values : Sort DataFrame by the values.
DataFrame.head : Return the first `n` rows without re-ordering.
Notes
-----
This function cannot be used with all column types. For example, when
specifying columns with `object` or `category` dtypes, ``TypeError`` is
raised.
Examples
--------
>>> df = pd.DataFrame({'population': [59000000, 65000000, 434000,
... 434000, 434000, 337000, 11300,
... 11300, 11300],
... 'GDP': [1937894, 2583560 , 12011, 4520, 12128,
... 17036, 182, 38, 311],
... 'alpha-2': ["IT", "FR", "MT", "MV", "BN",
... "IS", "NR", "TV", "AI"]},
... index=["Italy", "France", "Malta",
... "Maldives", "Brunei", "Iceland",
... "Nauru", "Tuvalu", "Anguilla"])
>>> df
population GDP alpha-2
Italy 59000000 1937894 IT
France 65000000 2583560 FR
Malta 434000 12011 MT
Maldives 434000 4520 MV
Brunei 434000 12128 BN
Iceland 337000 17036 IS
Nauru 11300 182 NR
Tuvalu 11300 38 TV
Anguilla 11300 311 AI
In the following example, we will use ``nlargest`` to select the three
rows having the largest values in column "population".
>>> df.nlargest(3, 'population')
population GDP alpha-2
France 65000000 2583560 FR
Italy 59000000 1937894 IT
Malta 434000 12011 MT
When using ``keep='last'``, ties are resolved in reverse order:
>>> df.nlargest(3, 'population', keep='last')
population GDP alpha-2
France 65000000 2583560 FR
Italy 59000000 1937894 IT
Brunei 434000 12128 BN
When using ``keep='all'``, all duplicate items are maintained:
>>> df.nlargest(3, 'population', keep='all')
population GDP alpha-2
France 65000000 2583560 FR
Italy 59000000 1937894 IT
Malta 434000 12011 MT
Maldives 434000 4520 MV
Brunei 434000 12128 BN
To order by the largest values in column "population" and then "GDP",
we can specify multiple columns like in the next example.
>>> df.nlargest(3, ['population', 'GDP'])
population GDP alpha-2
France 65000000 2583560 FR
Italy 59000000 1937894 IT
Brunei 434000 12128 BN
"""
return algorithms.SelectNFrame(self, n=n, keep=keep, columns=columns).nlargest()
def nsmallest(self, n, columns, keep="first") -> "DataFrame":
"""
Return the first `n` rows ordered by `columns` in ascending order.
Return the first `n` rows with the smallest values in `columns`, in
ascending order. The columns that are not specified are returned as
well, but not used for ordering.
This method is equivalent to
``df.sort_values(columns, ascending=True).head(n)``, but more
performant.
Parameters
----------
n : int
Number of items to retrieve.
columns : list or str
Column name or names to order by.
keep : {'first', 'last', 'all'}, default 'first'
Where there are duplicate values:
- ``first`` : take the first occurrence.
- ``last`` : take the last occurrence.
- ``all`` : do not drop any duplicates, even it means
selecting more than `n` items.
.. versionadded:: 0.24.0
Returns
-------
DataFrame
See Also
--------
DataFrame.nlargest : Return the first `n` rows ordered by `columns` in
descending order.
DataFrame.sort_values : Sort DataFrame by the values.
DataFrame.head : Return the first `n` rows without re-ordering.
Examples
--------
>>> df = pd.DataFrame({'population': [59000000, 65000000, 434000,
... 434000, 434000, 337000, 337000,
... 11300, 11300],
... 'GDP': [1937894, 2583560 , 12011, 4520, 12128,
... 17036, 182, 38, 311],
... 'alpha-2': ["IT", "FR", "MT", "MV", "BN",
... "IS", "NR", "TV", "AI"]},
... index=["Italy", "France", "Malta",
... "Maldives", "Brunei", "Iceland",
... "Nauru", "Tuvalu", "Anguilla"])
>>> df
population GDP alpha-2
Italy 59000000 1937894 IT
France 65000000 2583560 FR
Malta 434000 12011 MT
Maldives 434000 4520 MV
Brunei 434000 12128 BN
Iceland 337000 17036 IS
Nauru 337000 182 NR
Tuvalu 11300 38 TV
Anguilla 11300 311 AI
In the following example, we will use ``nsmallest`` to select the
three rows having the smallest values in column "population".
>>> df.nsmallest(3, 'population')
population GDP alpha-2
Tuvalu 11300 38 TV
Anguilla 11300 311 AI
Iceland 337000 17036 IS
When using ``keep='last'``, ties are resolved in reverse order:
>>> df.nsmallest(3, 'population', keep='last')
population GDP alpha-2
Anguilla 11300 311 AI
Tuvalu 11300 38 TV
Nauru 337000 182 NR
When using ``keep='all'``, all duplicate items are maintained:
>>> df.nsmallest(3, 'population', keep='all')
population GDP alpha-2
Tuvalu 11300 38 TV
Anguilla 11300 311 AI
Iceland 337000 17036 IS
Nauru 337000 182 NR
To order by the smallest values in column "population" and then "GDP", we can
specify multiple columns like in the next example.
>>> df.nsmallest(3, ['population', 'GDP'])
population GDP alpha-2
Tuvalu 11300 38 TV
Anguilla 11300 311 AI
Nauru 337000 182 NR
"""
return algorithms.SelectNFrame(
self, n=n, keep=keep, columns=columns
).nsmallest()
def swaplevel(self, i=-2, j=-1, axis=0) -> "DataFrame":
"""
Swap levels i and j in a MultiIndex on a particular axis.
Parameters
----------
i, j : int or str
Levels of the indices to be swapped. Can pass level name as string.
Returns
-------
DataFrame
"""
result = self.copy()
axis = self._get_axis_number(axis)
if not isinstance(result._get_axis(axis), ABCMultiIndex): # pragma: no cover
raise TypeError("Can only swap levels on a hierarchical axis.")
if axis == 0:
assert isinstance(result.index, ABCMultiIndex)
result.index = result.index.swaplevel(i, j)
else:
assert isinstance(result.columns, ABCMultiIndex)
result.columns = result.columns.swaplevel(i, j)
return result
def reorder_levels(self, order, axis=0) -> "DataFrame":
"""
Rearrange index levels using input order. May not drop or duplicate levels.
Parameters
----------
order : list of int or list of str
List representing new level order. Reference level by number
(position) or by key (label).
axis : int
Where to reorder levels.
Returns
-------
DataFrame
"""
axis = self._get_axis_number(axis)
if not isinstance(self._get_axis(axis), ABCMultiIndex): # pragma: no cover
raise TypeError("Can only reorder levels on a hierarchical axis.")
result = self.copy()
if axis == 0:
assert isinstance(result.index, ABCMultiIndex)
result.index = result.index.reorder_levels(order)
else:
assert isinstance(result.columns, ABCMultiIndex)
result.columns = result.columns.reorder_levels(order)
return result
# ----------------------------------------------------------------------
# Arithmetic / combination related
def _combine_frame(self, other: "DataFrame", func, fill_value=None):
# at this point we have `self._indexed_same(other)`
if fill_value is None:
# since _arith_op may be called in a loop, avoid function call
# overhead if possible by doing this check once
_arith_op = func
else:
def _arith_op(left, right):
# for the mixed_type case where we iterate over columns,
# _arith_op(left, right) is equivalent to
# left._binop(right, func, fill_value=fill_value)
left, right = ops.fill_binop(left, right, fill_value)
return func(left, right)
if ops.should_series_dispatch(self, other, func):
# iterate over columns
new_data = ops.dispatch_to_series(self, other, _arith_op)
else:
with np.errstate(all="ignore"):
res_values = _arith_op(self.values, other.values)
new_data = dispatch_fill_zeros(func, self.values, other.values, res_values)
return new_data
def _construct_result(self, result) -> "DataFrame":
"""
Wrap the result of an arithmetic, comparison, or logical operation.
Parameters
----------
result : DataFrame
Returns
-------
DataFrame
"""
out = self._constructor(result, index=self.index, copy=False)
# Pin columns instead of passing to constructor for compat with
# non-unique columns case
out.columns = self.columns
return out
def combine(
self, other: "DataFrame", func, fill_value=None, overwrite=True
) -> "DataFrame":
"""
Perform column-wise combine with another DataFrame.
Combines a DataFrame with `other` DataFrame using `func`
to element-wise combine columns. The row and column indexes of the
resulting DataFrame will be the union of the two.
Parameters
----------
other : DataFrame
The DataFrame to merge column-wise.
func : function
Function that takes two series as inputs and return a Series or a
scalar. Used to merge the two dataframes column by columns.
fill_value : scalar value, default None
The value to fill NaNs with prior to passing any column to the
merge func.
overwrite : bool, default True
If True, columns in `self` that do not exist in `other` will be
overwritten with NaNs.
Returns
-------
DataFrame
Combination of the provided DataFrames.
See Also
--------
DataFrame.combine_first : Combine two DataFrame objects and default to
non-null values in frame calling the method.
Examples
--------
Combine using a simple function that chooses the smaller column.
>>> df1 = pd.DataFrame({'A': [0, 0], 'B': [4, 4]})
>>> df2 = pd.DataFrame({'A': [1, 1], 'B': [3, 3]})
>>> take_smaller = lambda s1, s2: s1 if s1.sum() < s2.sum() else s2
>>> df1.combine(df2, take_smaller)
A B
0 0 3
1 0 3
Example using a true element-wise combine function.
>>> df1 = pd.DataFrame({'A': [5, 0], 'B': [2, 4]})
>>> df2 = pd.DataFrame({'A': [1, 1], 'B': [3, 3]})
>>> df1.combine(df2, np.minimum)
A B
0 1 2
1 0 3
Using `fill_value` fills Nones prior to passing the column to the
merge function.
>>> df1 = pd.DataFrame({'A': [0, 0], 'B': [None, 4]})
>>> df2 = pd.DataFrame({'A': [1, 1], 'B': [3, 3]})
>>> df1.combine(df2, take_smaller, fill_value=-5)
A B
0 0 -5.0
1 0 4.0
However, if the same element in both dataframes is None, that None
is preserved
>>> df1 = pd.DataFrame({'A': [0, 0], 'B': [None, 4]})
>>> df2 = pd.DataFrame({'A': [1, 1], 'B': [None, 3]})
>>> df1.combine(df2, take_smaller, fill_value=-5)
A B
0 0 -5.0
1 0 3.0
Example that demonstrates the use of `overwrite` and behavior when
the axis differ between the dataframes.
>>> df1 = pd.DataFrame({'A': [0, 0], 'B': [4, 4]})
>>> df2 = pd.DataFrame({'B': [3, 3], 'C': [-10, 1], }, index=[1, 2])
>>> df1.combine(df2, take_smaller)
A B C
0 NaN NaN NaN
1 NaN 3.0 -10.0
2 NaN 3.0 1.0
>>> df1.combine(df2, take_smaller, overwrite=False)
A B C
0 0.0 NaN NaN
1 0.0 3.0 -10.0
2 NaN 3.0 1.0
Demonstrating the preference of the passed in dataframe.
>>> df2 = pd.DataFrame({'B': [3, 3], 'C': [1, 1], }, index=[1, 2])
>>> df2.combine(df1, take_smaller)
A B C
0 0.0 NaN NaN
1 0.0 3.0 NaN
2 NaN 3.0 NaN
>>> df2.combine(df1, take_smaller, overwrite=False)
A B C
0 0.0 NaN NaN
1 0.0 3.0 1.0
2 NaN 3.0 1.0
"""
other_idxlen = len(other.index) # save for compare
this, other = self.align(other, copy=False)
new_index = this.index
if other.empty and len(new_index) == len(self.index):
return self.copy()
if self.empty and len(other) == other_idxlen:
return other.copy()
# sorts if possible
new_columns = this.columns.union(other.columns)
do_fill = fill_value is not None
result = {}
for col in new_columns:
series = this[col]
otherSeries = other[col]
this_dtype = series.dtype
other_dtype = otherSeries.dtype
this_mask = isna(series)
other_mask = isna(otherSeries)
# don't overwrite columns unnecessarily
# DO propagate if this column is not in the intersection
if not overwrite and other_mask.all():
result[col] = this[col].copy()
continue
if do_fill:
series = series.copy()
otherSeries = otherSeries.copy()
series[this_mask] = fill_value
otherSeries[other_mask] = fill_value
if col not in self.columns:
# If self DataFrame does not have col in other DataFrame,
# try to promote series, which is all NaN, as other_dtype.
new_dtype = other_dtype
try:
series = series.astype(new_dtype, copy=False)
except ValueError:
# e.g. new_dtype is integer types
pass
else:
# if we have different dtypes, possibly promote
new_dtype = find_common_type([this_dtype, other_dtype])
if not is_dtype_equal(this_dtype, new_dtype):
series = series.astype(new_dtype)
if not is_dtype_equal(other_dtype, new_dtype):
otherSeries = otherSeries.astype(new_dtype)
arr = func(series, otherSeries)
arr = maybe_downcast_to_dtype(arr, this_dtype)
result[col] = arr
# convert_objects just in case
return self._constructor(result, index=new_index, columns=new_columns)
def combine_first(self, other: "DataFrame") -> "DataFrame":
"""
Update null elements with value in the same location in `other`.
Combine two DataFrame objects by filling null values in one DataFrame
with non-null values from other DataFrame. The row and column indexes
of the resulting DataFrame will be the union of the two.
Parameters
----------
other : DataFrame
Provided DataFrame to use to fill null values.
Returns
-------
DataFrame
See Also
--------
DataFrame.combine : Perform series-wise operation on two DataFrames
using a given function.
Examples
--------
>>> df1 = pd.DataFrame({'A': [None, 0], 'B': [None, 4]})
>>> df2 = pd.DataFrame({'A': [1, 1], 'B': [3, 3]})
>>> df1.combine_first(df2)
A B
0 1.0 3.0
1 0.0 4.0
Null values still persist if the location of that null value
does not exist in `other`
>>> df1 = pd.DataFrame({'A': [None, 0], 'B': [4, None]})
>>> df2 = pd.DataFrame({'B': [3, 3], 'C': [1, 1]}, index=[1, 2])
>>> df1.combine_first(df2)
A B C
0 NaN 4.0 NaN
1 0.0 3.0 1.0
2 NaN 3.0 1.0
"""
import pandas.core.computation.expressions as expressions
def extract_values(arr):
# Does two things:
# 1. maybe gets the values from the Series / Index
# 2. convert datelike to i8
if isinstance(arr, (ABCIndexClass, ABCSeries)):
arr = arr._values
if needs_i8_conversion(arr):
if is_extension_array_dtype(arr.dtype):
arr = arr.asi8
else:
arr = arr.view("i8")
return arr
def combiner(x, y):
mask = isna(x)
if isinstance(mask, (ABCIndexClass, ABCSeries)):
mask = mask._values
x_values = extract_values(x)
y_values = extract_values(y)
# If the column y in other DataFrame is not in first DataFrame,
# just return y_values.
if y.name not in self.columns:
return y_values
return expressions.where(mask, y_values, x_values)
return self.combine(other, combiner, overwrite=False)
def update(
self, other, join="left", overwrite=True, filter_func=None, errors="ignore"
) -> None:
"""
Modify in place using non-NA values from another DataFrame.
Aligns on indices. There is no return value.
Parameters
----------
other : DataFrame, or object coercible into a DataFrame
Should have at least one matching index/column label
with the original DataFrame. If a Series is passed,
its name attribute must be set, and that will be
used as the column name to align with the original DataFrame.
join : {'left'}, default 'left'
Only left join is implemented, keeping the index and columns of the
original object.
overwrite : bool, default True
How to handle non-NA values for overlapping keys:
* True: overwrite original DataFrame's values
with values from `other`.
* False: only update values that are NA in
the original DataFrame.
filter_func : callable(1d-array) -> bool 1d-array, optional
Can choose to replace values other than NA. Return True for values
that should be updated.
errors : {'raise', 'ignore'}, default 'ignore'
If 'raise', will raise a ValueError if the DataFrame and `other`
both contain non-NA data in the same place.
.. versionchanged:: 0.24.0
Changed from `raise_conflict=False|True`
to `errors='ignore'|'raise'`.
Returns
-------
None : method directly changes calling object
Raises
------
ValueError
* When `errors='raise'` and there's overlapping non-NA data.
* When `errors` is not either `'ignore'` or `'raise'`
NotImplementedError
* If `join != 'left'`
See Also
--------
dict.update : Similar method for dictionaries.
DataFrame.merge : For column(s)-on-columns(s) operations.
Examples
--------
>>> df = pd.DataFrame({'A': [1, 2, 3],
... 'B': [400, 500, 600]})
>>> new_df = pd.DataFrame({'B': [4, 5, 6],
... 'C': [7, 8, 9]})
>>> df.update(new_df)
>>> df
A B
0 1 4
1 2 5
2 3 6
The DataFrame's length does not increase as a result of the update,
only values at matching index/column labels are updated.
>>> df = pd.DataFrame({'A': ['a', 'b', 'c'],
... 'B': ['x', 'y', 'z']})
>>> new_df = pd.DataFrame({'B': ['d', 'e', 'f', 'g', 'h', 'i']})
>>> df.update(new_df)
>>> df
A B
0 a d
1 b e
2 c f
For Series, it's name attribute must be set.
>>> df = pd.DataFrame({'A': ['a', 'b', 'c'],
... 'B': ['x', 'y', 'z']})
>>> new_column = pd.Series(['d', 'e'], name='B', index=[0, 2])
>>> df.update(new_column)
>>> df
A B
0 a d
1 b y
2 c e
>>> df = pd.DataFrame({'A': ['a', 'b', 'c'],
... 'B': ['x', 'y', 'z']})
>>> new_df = pd.DataFrame({'B': ['d', 'e']}, index=[1, 2])
>>> df.update(new_df)
>>> df
A B
0 a x
1 b d
2 c e
If `other` contains NaNs the corresponding values are not updated
in the original dataframe.
>>> df = pd.DataFrame({'A': [1, 2, 3],
... 'B': [400, 500, 600]})
>>> new_df = pd.DataFrame({'B': [4, np.nan, 6]})
>>> df.update(new_df)
>>> df
A B
0 1 4.0
1 2 500.0
2 3 6.0
"""
import pandas.core.computation.expressions as expressions
# TODO: Support other joins
if join != "left": # pragma: no cover
raise NotImplementedError("Only left join is supported")
if errors not in ["ignore", "raise"]:
raise ValueError("The parameter errors must be either 'ignore' or 'raise'")
if not isinstance(other, DataFrame):
other = DataFrame(other)
other = other.reindex_like(self)
for col in self.columns:
this = self[col]._values
that = other[col]._values
if filter_func is not None:
with np.errstate(all="ignore"):
mask = ~filter_func(this) | isna(that)
else:
if errors == "raise":
mask_this = notna(that)
mask_that = notna(this)
if any(mask_this & mask_that):
raise ValueError("Data overlaps.")
if overwrite:
mask = isna(that)
else:
mask = notna(this)
# don't overwrite columns unnecessarily
if mask.all():
continue
self[col] = expressions.where(mask, this, that)
# ----------------------------------------------------------------------
# Data reshaping
@Appender(
"""
Examples
--------
>>> df = pd.DataFrame({'Animal': ['Falcon', 'Falcon',
... 'Parrot', 'Parrot'],
... 'Max Speed': [380., 370., 24., 26.]})
>>> df
Animal Max Speed
0 Falcon 380.0
1 Falcon 370.0
2 Parrot 24.0
3 Parrot 26.0
>>> df.groupby(['Animal']).mean()
Max Speed
Animal
Falcon 375.0
Parrot 25.0
**Hierarchical Indexes**
We can groupby different levels of a hierarchical index
using the `level` parameter:
>>> arrays = [['Falcon', 'Falcon', 'Parrot', 'Parrot'],
... ['Captive', 'Wild', 'Captive', 'Wild']]
>>> index = pd.MultiIndex.from_arrays(arrays, names=('Animal', 'Type'))
>>> df = pd.DataFrame({'Max Speed': [390., 350., 30., 20.]},
... index=index)
>>> df
Max Speed
Animal Type
Falcon Captive 390.0
Wild 350.0
Parrot Captive 30.0
Wild 20.0
>>> df.groupby(level=0).mean()
Max Speed
Animal
Falcon 370.0
Parrot 25.0
>>> df.groupby(level="Type").mean()
Max Speed
Type
Captive 210.0
Wild 185.0
"""
)
@Appender(_shared_docs["groupby"] % _shared_doc_kwargs)
def groupby(
self,
by=None,
axis=0,
level=None,
as_index: bool = True,
sort: bool = True,
group_keys: bool = True,
squeeze: bool = False,
observed: bool = False,
) -> "DataFrameGroupBy":
from pandas.core.groupby.generic import DataFrameGroupBy
if level is None and by is None:
raise TypeError("You have to supply one of 'by' and 'level'")
axis = self._get_axis_number(axis)
return DataFrameGroupBy(
obj=self,
keys=by,
axis=axis,
level=level,
as_index=as_index,
sort=sort,
group_keys=group_keys,
squeeze=squeeze,
observed=observed,
)
_shared_docs[
"pivot"
] = """
Return reshaped DataFrame organized by given index / column values.
Reshape data (produce a "pivot" table) based on column values. Uses
unique values from specified `index` / `columns` to form axes of the
resulting DataFrame. This function does not support data
aggregation, multiple values will result in a MultiIndex in the
columns. See the :ref:`User Guide <reshaping>` for more on reshaping.
Parameters
----------%s
index : str or object or a list of str, optional
Column to use to make new frame's index. If None, uses
existing index.
.. versionchanged:: 1.1.0
Also accept list of index names.
columns : str or object or a list of str
Column to use to make new frame's columns.
.. versionchanged:: 1.1.0
Also accept list of columns names.
values : str, object or a list of the previous, optional
Column(s) to use for populating new frame's values. If not
specified, all remaining columns will be used and the result will
have hierarchically indexed columns.
.. versionchanged:: 0.23.0
Also accept list of column names.
Returns
-------
DataFrame
Returns reshaped DataFrame.
Raises
------
ValueError:
When there are any `index`, `columns` combinations with multiple
values. `DataFrame.pivot_table` when you need to aggregate.
See Also
--------
DataFrame.pivot_table : Generalization of pivot that can handle
duplicate values for one index/column pair.
DataFrame.unstack : Pivot based on the index values instead of a
column.
Notes
-----
For finer-tuned control, see hierarchical indexing documentation along
with the related stack/unstack methods.
Examples
--------
>>> df = pd.DataFrame({'foo': ['one', 'one', 'one', 'two', 'two',
... 'two'],
... 'bar': ['A', 'B', 'C', 'A', 'B', 'C'],
... 'baz': [1, 2, 3, 4, 5, 6],
... 'zoo': ['x', 'y', 'z', 'q', 'w', 't']})
>>> df
foo bar baz zoo
0 one A 1 x
1 one B 2 y
2 one C 3 z
3 two A 4 q
4 two B 5 w
5 two C 6 t
>>> df.pivot(index='foo', columns='bar', values='baz')
bar A B C
foo
one 1 2 3
two 4 5 6
>>> df.pivot(index='foo', columns='bar')['baz']
bar A B C
foo
one 1 2 3
two 4 5 6
>>> df.pivot(index='foo', columns='bar', values=['baz', 'zoo'])
baz zoo
bar A B C A B C
foo
one 1 2 3 x y z
two 4 5 6 q w t
You could also assign a list of column names or a list of index names.
>>> df = pd.DataFrame({
... "lev1": [1, 1, 1, 2, 2, 2],
... "lev2": [1, 1, 2, 1, 1, 2],
... "lev3": [1, 2, 1, 2, 1, 2],
... "lev4": [1, 2, 3, 4, 5, 6],
... "values": [0, 1, 2, 3, 4, 5]})
>>> df
lev1 lev2 lev3 lev4 values
0 1 1 1 1 0
1 1 1 2 2 1
2 1 2 1 3 2
3 2 1 2 4 3
4 2 1 1 5 4
5 2 2 2 6 5
>>> df.pivot(index="lev1", columns=["lev2", "lev3"],values="values")
lev2 1 2
lev3 1 2 1 2
lev1
1 0.0 1.0 2.0 NaN
2 4.0 3.0 NaN 5.0
>>> df.pivot(index=["lev1", "lev2"], columns=["lev3"],values="values")
lev3 1 2
lev1 lev2
1 1 0.0 1.0
2 2.0 NaN
2 1 4.0 3.0
2 NaN 5.0
A ValueError is raised if there are any duplicates.
>>> df = pd.DataFrame({"foo": ['one', 'one', 'two', 'two'],
... "bar": ['A', 'A', 'B', 'C'],
... "baz": [1, 2, 3, 4]})
>>> df
foo bar baz
0 one A 1
1 one A 2
2 two B 3
3 two C 4
Notice that the first two rows are the same for our `index`
and `columns` arguments.
>>> df.pivot(index='foo', columns='bar', values='baz')
Traceback (most recent call last):
...
ValueError: Index contains duplicate entries, cannot reshape
"""
@Substitution("")
@Appender(_shared_docs["pivot"])
def pivot(self, index=None, columns=None, values=None) -> "DataFrame":
from pandas.core.reshape.pivot import pivot
return pivot(self, index=index, columns=columns, values=values)
_shared_docs[
"pivot_table"
] = """
Create a spreadsheet-style pivot table as a DataFrame.
The levels in the pivot table will be stored in MultiIndex objects
(hierarchical indexes) on the index and columns of the result DataFrame.
Parameters
----------%s
values : column to aggregate, optional
index : column, Grouper, array, or list of the previous
If an array is passed, it must be the same length as the data. The
list can contain any of the other types (except list).
Keys to group by on the pivot table index. If an array is passed,
it is being used as the same manner as column values.
columns : column, Grouper, array, or list of the previous
If an array is passed, it must be the same length as the data. The
list can contain any of the other types (except list).
Keys to group by on the pivot table column. If an array is passed,
it is being used as the same manner as column values.
aggfunc : function, list of functions, dict, default numpy.mean
If list of functions passed, the resulting pivot table will have
hierarchical columns whose top level are the function names
(inferred from the function objects themselves)
If dict is passed, the key is column to aggregate and value
is function or list of functions.
fill_value : scalar, default None
Value to replace missing values with (in the resulting pivot table,
after aggregation).
margins : bool, default False
Add all row / columns (e.g. for subtotal / grand totals).
dropna : bool, default True
Do not include columns whose entries are all NaN.
margins_name : str, default 'All'
Name of the row / column that will contain the totals
when margins is True.
observed : bool, default False
This only applies if any of the groupers are Categoricals.
If True: only show observed values for categorical groupers.
If False: show all values for categorical groupers.
.. versionchanged:: 0.25.0
Returns
-------
DataFrame
An Excel style pivot table.
See Also
--------
DataFrame.pivot : Pivot without aggregation that can handle
non-numeric data.
Examples
--------
>>> df = pd.DataFrame({"A": ["foo", "foo", "foo", "foo", "foo",
... "bar", "bar", "bar", "bar"],
... "B": ["one", "one", "one", "two", "two",
... "one", "one", "two", "two"],
... "C": ["small", "large", "large", "small",
... "small", "large", "small", "small",
... "large"],
... "D": [1, 2, 2, 3, 3, 4, 5, 6, 7],
... "E": [2, 4, 5, 5, 6, 6, 8, 9, 9]})
>>> df
A B C D E
0 foo one small 1 2
1 foo one large 2 4
2 foo one large 2 5
3 foo two small 3 5
4 foo two small 3 6
5 bar one large 4 6
6 bar one small 5 8
7 bar two small 6 9
8 bar two large 7 9
This first example aggregates values by taking the sum.
>>> table = pd.pivot_table(df, values='D', index=['A', 'B'],
... columns=['C'], aggfunc=np.sum)
>>> table
C large small
A B
bar one 4.0 5.0
two 7.0 6.0
foo one 4.0 1.0
two NaN 6.0
We can also fill missing values using the `fill_value` parameter.
>>> table = pd.pivot_table(df, values='D', index=['A', 'B'],
... columns=['C'], aggfunc=np.sum, fill_value=0)
>>> table
C large small
A B
bar one 4 5
two 7 6
foo one 4 1
two 0 6
The next example aggregates by taking the mean across multiple columns.
>>> table = pd.pivot_table(df, values=['D', 'E'], index=['A', 'C'],
... aggfunc={'D': np.mean,
... 'E': np.mean})
>>> table
D E
A C
bar large 5.500000 7.500000
small 5.500000 8.500000
foo large 2.000000 4.500000
small 2.333333 4.333333
We can also calculate multiple types of aggregations for any given
value column.
>>> table = pd.pivot_table(df, values=['D', 'E'], index=['A', 'C'],
... aggfunc={'D': np.mean,
... 'E': [min, max, np.mean]})
>>> table
D E
mean max mean min
A C
bar large 5.500000 9.0 7.500000 6.0
small 5.500000 9.0 8.500000 8.0
foo large 2.000000 5.0 4.500000 4.0
small 2.333333 6.0 4.333333 2.0
"""
@Substitution("")
@Appender(_shared_docs["pivot_table"])
def pivot_table(
self,
values=None,
index=None,
columns=None,
aggfunc="mean",
fill_value=None,
margins=False,
dropna=True,
margins_name="All",
observed=False,
) -> "DataFrame":
from pandas.core.reshape.pivot import pivot_table
return pivot_table(
self,
values=values,
index=index,
columns=columns,
aggfunc=aggfunc,
fill_value=fill_value,
margins=margins,
dropna=dropna,
margins_name=margins_name,
observed=observed,
)
def stack(self, level=-1, dropna=True):
"""
Stack the prescribed level(s) from columns to index.
Return a reshaped DataFrame or Series having a multi-level
index with one or more new inner-most levels compared to the current
DataFrame. The new inner-most levels are created by pivoting the
columns of the current dataframe:
- if the columns have a single level, the output is a Series;
- if the columns have multiple levels, the new index
level(s) is (are) taken from the prescribed level(s) and
the output is a DataFrame.
The new index levels are sorted.
Parameters
----------
level : int, str, list, default -1
Level(s) to stack from the column axis onto the index
axis, defined as one index or label, or a list of indices
or labels.
dropna : bool, default True
Whether to drop rows in the resulting Frame/Series with
missing values. Stacking a column level onto the index
axis can create combinations of index and column values
that are missing from the original dataframe. See Examples
section.
Returns
-------
DataFrame or Series
Stacked dataframe or series.
See Also
--------
DataFrame.unstack : Unstack prescribed level(s) from index axis
onto column axis.
DataFrame.pivot : Reshape dataframe from long format to wide
format.
DataFrame.pivot_table : Create a spreadsheet-style pivot table
as a DataFrame.
Notes
-----
The function is named by analogy with a collection of books
being reorganized from being side by side on a horizontal
position (the columns of the dataframe) to being stacked
vertically on top of each other (in the index of the
dataframe).
Examples
--------
**Single level columns**
>>> df_single_level_cols = pd.DataFrame([[0, 1], [2, 3]],
... index=['cat', 'dog'],
... columns=['weight', 'height'])
Stacking a dataframe with a single level column axis returns a Series:
>>> df_single_level_cols
weight height
cat 0 1
dog 2 3
>>> df_single_level_cols.stack()
cat weight 0
height 1
dog weight 2
height 3
dtype: int64
**Multi level columns: simple case**
>>> multicol1 = pd.MultiIndex.from_tuples([('weight', 'kg'),
... ('weight', 'pounds')])
>>> df_multi_level_cols1 = pd.DataFrame([[1, 2], [2, 4]],
... index=['cat', 'dog'],
... columns=multicol1)
Stacking a dataframe with a multi-level column axis:
>>> df_multi_level_cols1
weight
kg pounds
cat 1 2
dog 2 4
>>> df_multi_level_cols1.stack()
weight
cat kg 1
pounds 2
dog kg 2
pounds 4
**Missing values**
>>> multicol2 = pd.MultiIndex.from_tuples([('weight', 'kg'),
... ('height', 'm')])
>>> df_multi_level_cols2 = pd.DataFrame([[1.0, 2.0], [3.0, 4.0]],
... index=['cat', 'dog'],
... columns=multicol2)
It is common to have missing values when stacking a dataframe
with multi-level columns, as the stacked dataframe typically
has more values than the original dataframe. Missing values
are filled with NaNs:
>>> df_multi_level_cols2
weight height
kg m
cat 1.0 2.0
dog 3.0 4.0
>>> df_multi_level_cols2.stack()
height weight
cat kg NaN 1.0
m 2.0 NaN
dog kg NaN 3.0
m 4.0 NaN
**Prescribing the level(s) to be stacked**
The first parameter controls which level or levels are stacked:
>>> df_multi_level_cols2.stack(0)
kg m
cat height NaN 2.0
weight 1.0 NaN
dog height NaN 4.0
weight 3.0 NaN
>>> df_multi_level_cols2.stack([0, 1])
cat height m 2.0
weight kg 1.0
dog height m 4.0
weight kg 3.0
dtype: float64
**Dropping missing values**
>>> df_multi_level_cols3 = pd.DataFrame([[None, 1.0], [2.0, 3.0]],
... index=['cat', 'dog'],
... columns=multicol2)
Note that rows where all values are missing are dropped by
default but this behaviour can be controlled via the dropna
keyword parameter:
>>> df_multi_level_cols3
weight height
kg m
cat NaN 1.0
dog 2.0 3.0
>>> df_multi_level_cols3.stack(dropna=False)
height weight
cat kg NaN NaN
m 1.0 NaN
dog kg NaN 2.0
m 3.0 NaN
>>> df_multi_level_cols3.stack(dropna=True)
height weight
cat m 1.0 NaN
dog kg NaN 2.0
m 3.0 NaN
"""
from pandas.core.reshape.reshape import stack, stack_multiple
if isinstance(level, (tuple, list)):
return stack_multiple(self, level, dropna=dropna)
else:
return stack(self, level, dropna=dropna)
def explode(self, column: Union[str, Tuple]) -> "DataFrame":
"""
Transform each element of a list-like to a row, replicating index values.
.. versionadded:: 0.25.0
Parameters
----------
column : str or tuple
Column to explode.
Returns
-------
DataFrame
Exploded lists to rows of the subset columns;
index will be duplicated for these rows.
Raises
------
ValueError :
if columns of the frame are not unique.
See Also
--------
DataFrame.unstack : Pivot a level of the (necessarily hierarchical)
index labels.
DataFrame.melt : Unpivot a DataFrame from wide format to long format.
Series.explode : Explode a DataFrame from list-like columns to long format.
Notes
-----
This routine will explode list-likes including lists, tuples,
Series, and np.ndarray. The result dtype of the subset rows will
be object. Scalars will be returned unchanged. Empty list-likes will
result in a np.nan for that row.
Examples
--------
>>> df = pd.DataFrame({'A': [[1, 2, 3], 'foo', [], [3, 4]], 'B': 1})
>>> df
A B
0 [1, 2, 3] 1
1 foo 1
2 [] 1
3 [3, 4] 1
>>> df.explode('A')
A B
0 1 1
0 2 1
0 3 1
1 foo 1
2 NaN 1
3 3 1
3 4 1
"""
if not (is_scalar(column) or isinstance(column, tuple)):
raise ValueError("column must be a scalar")
if not self.columns.is_unique:
raise ValueError("columns must be unique")
df = self.reset_index(drop=True)
# TODO: use overload to refine return type of reset_index
assert df is not None # needed for mypy
result = df[column].explode()
result = df.drop([column], axis=1).join(result)
result.index = self.index.take(result.index)
result = result.reindex(columns=self.columns, copy=False)
return result
def unstack(self, level=-1, fill_value=None):
"""
Pivot a level of the (necessarily hierarchical) index labels.
Returns a DataFrame having a new level of column labels whose inner-most level
consists of the pivoted index labels.
If the index is not a MultiIndex, the output will be a Series
(the analogue of stack when the columns are not a MultiIndex).
The level involved will automatically get sorted.
Parameters
----------
level : int, str, or list of these, default -1 (last level)
Level(s) of index to unstack, can pass level name.
fill_value : int, str or dict
Replace NaN with this value if the unstack produces missing values.
Returns
-------
Series or DataFrame
See Also
--------
DataFrame.pivot : Pivot a table based on column values.
DataFrame.stack : Pivot a level of the column labels (inverse operation
from `unstack`).
Examples
--------
>>> index = pd.MultiIndex.from_tuples([('one', 'a'), ('one', 'b'),
... ('two', 'a'), ('two', 'b')])
>>> s = pd.Series(np.arange(1.0, 5.0), index=index)
>>> s
one a 1.0
b 2.0
two a 3.0
b 4.0
dtype: float64
>>> s.unstack(level=-1)
a b
one 1.0 2.0
two 3.0 4.0
>>> s.unstack(level=0)
one two
a 1.0 3.0
b 2.0 4.0
>>> df = s.unstack(level=0)
>>> df.unstack()
one a 1.0
b 2.0
two a 3.0
b 4.0
dtype: float64
"""
from pandas.core.reshape.reshape import unstack
return unstack(self, level, fill_value)
_shared_docs[
"melt"
] = """
Unpivot a DataFrame from wide to long format, optionally leaving identifiers set.
This function is useful to massage a DataFrame into a format where one
or more columns are identifier variables (`id_vars`), while all other
columns, considered measured variables (`value_vars`), are "unpivoted" to
the row axis, leaving just two non-identifier columns, 'variable' and
'value'.
%(versionadded)s
Parameters
----------
id_vars : tuple, list, or ndarray, optional
Column(s) to use as identifier variables.
value_vars : tuple, list, or ndarray, optional
Column(s) to unpivot. If not specified, uses all columns that
are not set as `id_vars`.
var_name : scalar
Name to use for the 'variable' column. If None it uses
``frame.columns.name`` or 'variable'.
value_name : scalar, default 'value'
Name to use for the 'value' column.
col_level : int or str, optional
If columns are a MultiIndex then use this level to melt.
Returns
-------
DataFrame
Unpivoted DataFrame.
See Also
--------
%(other)s
pivot_table
DataFrame.pivot
Series.explode
Examples
--------
>>> df = pd.DataFrame({'A': {0: 'a', 1: 'b', 2: 'c'},
... 'B': {0: 1, 1: 3, 2: 5},
... 'C': {0: 2, 1: 4, 2: 6}})
>>> df
A B C
0 a 1 2
1 b 3 4
2 c 5 6
>>> %(caller)sid_vars=['A'], value_vars=['B'])
A variable value
0 a B 1
1 b B 3
2 c B 5
>>> %(caller)sid_vars=['A'], value_vars=['B', 'C'])
A variable value
0 a B 1
1 b B 3
2 c B 5
3 a C 2
4 b C 4
5 c C 6
The names of 'variable' and 'value' columns can be customized:
>>> %(caller)sid_vars=['A'], value_vars=['B'],
... var_name='myVarname', value_name='myValname')
A myVarname myValname
0 a B 1
1 b B 3
2 c B 5
If you have multi-index columns:
>>> df.columns = [list('ABC'), list('DEF')]
>>> df
A B C
D E F
0 a 1 2
1 b 3 4
2 c 5 6
>>> %(caller)scol_level=0, id_vars=['A'], value_vars=['B'])
A variable value
0 a B 1
1 b B 3
2 c B 5
>>> %(caller)sid_vars=[('A', 'D')], value_vars=[('B', 'E')])
(A, D) variable_0 variable_1 value
0 a B E 1
1 b B E 3
2 c B E 5
"""
@Appender(
_shared_docs["melt"]
% dict(
caller="df.melt(",
versionadded="\n .. versionadded:: 0.20.0\n",
other="melt",
)
)
def melt(
self,
id_vars=None,
value_vars=None,
var_name=None,
value_name="value",
col_level=None,
) -> "DataFrame":
from pandas.core.reshape.melt import melt
return melt(
self,
id_vars=id_vars,
value_vars=value_vars,
var_name=var_name,
value_name=value_name,
col_level=col_level,
)
# ----------------------------------------------------------------------
# Time series-related
def diff(self, periods=1, axis=0) -> "DataFrame":
"""
First discrete difference of element.
Calculates the difference of a DataFrame element compared with another
element in the DataFrame (default is the element in the same column
of the previous row).
Parameters
----------
periods : int, default 1
Periods to shift for calculating difference, accepts negative
values.
axis : {0 or 'index', 1 or 'columns'}, default 0
Take difference over rows (0) or columns (1).
Returns
-------
DataFrame
See Also
--------
Series.diff: First discrete difference for a Series.
DataFrame.pct_change: Percent change over given number of periods.
DataFrame.shift: Shift index by desired number of periods with an
optional time freq.
Notes
-----
For boolean dtypes, this uses :meth:`operator.xor` rather than
:meth:`operator.sub`.
Examples
--------
Difference with previous row
>>> df = pd.DataFrame({'a': [1, 2, 3, 4, 5, 6],
... 'b': [1, 1, 2, 3, 5, 8],
... 'c': [1, 4, 9, 16, 25, 36]})
>>> df
a b c
0 1 1 1
1 2 1 4
2 3 2 9
3 4 3 16
4 5 5 25
5 6 8 36
>>> df.diff()
a b c
0 NaN NaN NaN
1 1.0 0.0 3.0
2 1.0 1.0 5.0
3 1.0 1.0 7.0
4 1.0 2.0 9.0
5 1.0 3.0 11.0
Difference with previous column
>>> df.diff(axis=1)
a b c
0 NaN 0.0 0.0
1 NaN -1.0 3.0
2 NaN -1.0 7.0
3 NaN -1.0 13.0
4 NaN 0.0 20.0
5 NaN 2.0 28.0
Difference with 3rd previous row
>>> df.diff(periods=3)
a b c
0 NaN NaN NaN
1 NaN NaN NaN
2 NaN NaN NaN
3 3.0 2.0 15.0
4 3.0 4.0 21.0
5 3.0 6.0 27.0
Difference with following row
>>> df.diff(periods=-1)
a b c
0 -1.0 0.0 -3.0
1 -1.0 -1.0 -5.0
2 -1.0 -1.0 -7.0
3 -1.0 -2.0 -9.0
4 -1.0 -3.0 -11.0
5 NaN NaN NaN
"""
bm_axis = self._get_block_manager_axis(axis)
new_data = self._data.diff(n=periods, axis=bm_axis)
return self._constructor(new_data)
# ----------------------------------------------------------------------
# Function application
def _gotitem(
self,
key: Union[str, List[str]],
ndim: int,
subset: Optional[Union[Series, ABCDataFrame]] = None,
) -> Union[Series, ABCDataFrame]:
"""
Sub-classes to define. Return a sliced object.
Parameters
----------
key : string / list of selections
ndim : 1,2
requested ndim of result
subset : object, default None
subset to act on
"""
if subset is None:
subset = self
elif subset.ndim == 1: # is Series
return subset
# TODO: _shallow_copy(subset)?
return subset[key]
_agg_summary_and_see_also_doc = dedent(
"""
The aggregation operations are always performed over an axis, either the
index (default) or the column axis. This behavior is different from
`numpy` aggregation functions (`mean`, `median`, `prod`, `sum`, `std`,
`var`), where the default is to compute the aggregation of the flattened
array, e.g., ``numpy.mean(arr_2d)`` as opposed to
``numpy.mean(arr_2d, axis=0)``.
`agg` is an alias for `aggregate`. Use the alias.
See Also
--------
DataFrame.apply : Perform any type of operations.
DataFrame.transform : Perform transformation type operations.
core.groupby.GroupBy : Perform operations over groups.
core.resample.Resampler : Perform operations over resampled bins.
core.window.Rolling : Perform operations over rolling window.
core.window.Expanding : Perform operations over expanding window.
core.window.EWM : Perform operation over exponential weighted
window.
"""
)
_agg_examples_doc = dedent(
"""
Examples
--------
>>> df = pd.DataFrame([[1, 2, 3],
... [4, 5, 6],
... [7, 8, 9],
... [np.nan, np.nan, np.nan]],
... columns=['A', 'B', 'C'])
Aggregate these functions over the rows.
>>> df.agg(['sum', 'min'])
A B C
sum 12.0 15.0 18.0
min 1.0 2.0 3.0
Different aggregations per column.
>>> df.agg({'A' : ['sum', 'min'], 'B' : ['min', 'max']})
A B
max NaN 8.0
min 1.0 2.0
sum 12.0 NaN
Aggregate over the columns.
>>> df.agg("mean", axis="columns")
0 2.0
1 5.0
2 8.0
3 NaN
dtype: float64
"""
)
@Substitution(
see_also=_agg_summary_and_see_also_doc,
examples=_agg_examples_doc,
versionadded="\n.. versionadded:: 0.20.0\n",
**_shared_doc_kwargs,
)
@Appender(_shared_docs["aggregate"])
def aggregate(self, func, axis=0, *args, **kwargs):
axis = self._get_axis_number(axis)
result = None
try:
result, how = self._aggregate(func, axis=axis, *args, **kwargs)
except TypeError:
pass
if result is None:
return self.apply(func, axis=axis, args=args, **kwargs)
return result
def _aggregate(self, arg, axis=0, *args, **kwargs):
if axis == 1:
# NDFrame.aggregate returns a tuple, and we need to transpose
# only result
result, how = self.T._aggregate(arg, *args, **kwargs)
result = result.T if result is not None else result
return result, how
return super()._aggregate(arg, *args, **kwargs)
agg = aggregate
@Appender(_shared_docs["transform"] % _shared_doc_kwargs)
def transform(self, func, axis=0, *args, **kwargs) -> "DataFrame":
axis = self._get_axis_number(axis)
if axis == 1:
return self.T.transform(func, *args, **kwargs).T
return super().transform(func, *args, **kwargs)
def apply(self, func, axis=0, raw=False, result_type=None, args=(), **kwds):
"""
Apply a function along an axis of the DataFrame.
Objects passed to the function are Series objects whose index is
either the DataFrame's index (``axis=0``) or the DataFrame's columns
(``axis=1``). By default (``result_type=None``), the final return type
is inferred from the return type of the applied function. Otherwise,
it depends on the `result_type` argument.
Parameters
----------
func : function
Function to apply to each column or row.
axis : {0 or 'index', 1 or 'columns'}, default 0
Axis along which the function is applied:
* 0 or 'index': apply function to each column.
* 1 or 'columns': apply function to each row.
raw : bool, default False
Determines if row or column is passed as a Series or ndarray object:
* ``False`` : passes each row or column as a Series to the
function.
* ``True`` : the passed function will receive ndarray objects
instead.
If you are just applying a NumPy reduction function this will
achieve much better performance.
result_type : {'expand', 'reduce', 'broadcast', None}, default None
These only act when ``axis=1`` (columns):
* 'expand' : list-like results will be turned into columns.
* 'reduce' : returns a Series if possible rather than expanding
list-like results. This is the opposite of 'expand'.
* 'broadcast' : results will be broadcast to the original shape
of the DataFrame, the original index and columns will be
retained.
The default behaviour (None) depends on the return value of the
applied function: list-like results will be returned as a Series
of those. However if the apply function returns a Series these
are expanded to columns.
.. versionadded:: 0.23.0
args : tuple
Positional arguments to pass to `func` in addition to the
array/series.
**kwds
Additional keyword arguments to pass as keywords arguments to
`func`.
Returns
-------
Series or DataFrame
Result of applying ``func`` along the given axis of the
DataFrame.
See Also
--------
DataFrame.applymap: For elementwise operations.
DataFrame.aggregate: Only perform aggregating type operations.
DataFrame.transform: Only perform transforming type operations.
Examples
--------
>>> df = pd.DataFrame([[4, 9]] * 3, columns=['A', 'B'])
>>> df
A B
0 4 9
1 4 9
2 4 9
Using a numpy universal function (in this case the same as
``np.sqrt(df)``):
>>> df.apply(np.sqrt)
A B
0 2.0 3.0
1 2.0 3.0
2 2.0 3.0
Using a reducing function on either axis
>>> df.apply(np.sum, axis=0)
A 12
B 27
dtype: int64
>>> df.apply(np.sum, axis=1)
0 13
1 13
2 13
dtype: int64
Returning a list-like will result in a Series
>>> df.apply(lambda x: [1, 2], axis=1)
0 [1, 2]
1 [1, 2]
2 [1, 2]
dtype: object
Passing result_type='expand' will expand list-like results
to columns of a Dataframe
>>> df.apply(lambda x: [1, 2], axis=1, result_type='expand')
0 1
0 1 2
1 1 2
2 1 2
Returning a Series inside the function is similar to passing
``result_type='expand'``. The resulting column names
will be the Series index.
>>> df.apply(lambda x: pd.Series([1, 2], index=['foo', 'bar']), axis=1)
foo bar
0 1 2
1 1 2
2 1 2
Passing ``result_type='broadcast'`` will ensure the same shape
result, whether list-like or scalar is returned by the function,
and broadcast it along the axis. The resulting column names will
be the originals.
>>> df.apply(lambda x: [1, 2], axis=1, result_type='broadcast')
A B
0 1 2
1 1 2
2 1 2
"""
from pandas.core.apply import frame_apply
op = frame_apply(
self,
func=func,
axis=axis,
raw=raw,
result_type=result_type,
args=args,
kwds=kwds,
)
return op.get_result()
def applymap(self, func) -> "DataFrame":
"""
Apply a function to a Dataframe elementwise.
This method applies a function that accepts and returns a scalar
to every element of a DataFrame.
Parameters
----------
func : callable
Python function, returns a single value from a single value.
Returns
-------
DataFrame
Transformed DataFrame.
See Also
--------
DataFrame.apply : Apply a function along input axis of DataFrame.
Notes
-----
In the current implementation applymap calls `func` twice on the
first column/row to decide whether it can take a fast or slow
code path. This can lead to unexpected behavior if `func` has
side-effects, as they will take effect twice for the first
column/row.
Examples
--------
>>> df = pd.DataFrame([[1, 2.12], [3.356, 4.567]])
>>> df
0 1
0 1.000 2.120
1 3.356 4.567
>>> df.applymap(lambda x: len(str(x)))
0 1
0 3 4
1 5 5
Note that a vectorized version of `func` often exists, which will
be much faster. You could square each number elementwise.
>>> df.applymap(lambda x: x**2)
0 1
0 1.000000 4.494400
1 11.262736 20.857489
But it's better to avoid applymap in that case.
>>> df ** 2
0 1
0 1.000000 4.494400
1 11.262736 20.857489
"""
# if we have a dtype == 'M8[ns]', provide boxed values
def infer(x):
if x.empty:
return lib.map_infer(x, func)
return lib.map_infer(x.astype(object).values, func)
return self.apply(infer)
# ----------------------------------------------------------------------
# Merging / joining methods
def append(
self, other, ignore_index=False, verify_integrity=False, sort=False
) -> "DataFrame":
"""
Append rows of `other` to the end of caller, returning a new object.
Columns in `other` that are not in the caller are added as new columns.
Parameters
----------
other : DataFrame or Series/dict-like object, or list of these
The data to append.
ignore_index : bool, default False
If True, do not use the index labels.
verify_integrity : bool, default False
If True, raise ValueError on creating index with duplicates.
sort : bool, default False
Sort columns if the columns of `self` and `other` are not aligned.
.. versionadded:: 0.23.0
.. versionchanged:: 1.0.0
Changed to not sort by default.
Returns
-------
DataFrame
See Also
--------
concat : General function to concatenate DataFrame or Series objects.
Notes
-----
If a list of dict/series is passed and the keys are all contained in
the DataFrame's index, the order of the columns in the resulting
DataFrame will be unchanged.
Iteratively appending rows to a DataFrame can be more computationally
intensive than a single concatenate. A better solution is to append
those rows to a list and then concatenate the list with the original
DataFrame all at once.
Examples
--------
>>> df = pd.DataFrame([[1, 2], [3, 4]], columns=list('AB'))
>>> df
A B
0 1 2
1 3 4
>>> df2 = pd.DataFrame([[5, 6], [7, 8]], columns=list('AB'))
>>> df.append(df2)
A B
0 1 2
1 3 4
0 5 6
1 7 8
With `ignore_index` set to True:
>>> df.append(df2, ignore_index=True)
A B
0 1 2
1 3 4
2 5 6
3 7 8
The following, while not recommended methods for generating DataFrames,
show two ways to generate a DataFrame from multiple data sources.
Less efficient:
>>> df = pd.DataFrame(columns=['A'])
>>> for i in range(5):
... df = df.append({'A': i}, ignore_index=True)
>>> df
A
0 0
1 1
2 2
3 3
4 4
More efficient:
>>> pd.concat([pd.DataFrame([i], columns=['A']) for i in range(5)],
... ignore_index=True)
A
0 0
1 1
2 2
3 3
4 4
"""
if isinstance(other, (Series, dict)):
if isinstance(other, dict):
if not ignore_index:
raise TypeError("Can only append a dict if ignore_index=True")
other = Series(other)
if other.name is None and not ignore_index:
raise TypeError(
"Can only append a Series if ignore_index=True "
"or if the Series has a name"
)
index = Index([other.name], name=self.index.name)
idx_diff = other.index.difference(self.columns)
try:
combined_columns = self.columns.append(idx_diff)
except TypeError:
combined_columns = self.columns.astype(object).append(idx_diff)
other = (
other.reindex(combined_columns, copy=False)
.to_frame()
.T.infer_objects()
.rename_axis(index.names, copy=False)
)
if not self.columns.equals(combined_columns):
self = self.reindex(columns=combined_columns)
elif isinstance(other, list):
if not other:
pass
elif not isinstance(other[0], DataFrame):
other = DataFrame(other)
if (self.columns.get_indexer(other.columns) >= 0).all():
other = other.reindex(columns=self.columns)
from pandas.core.reshape.concat import concat
if isinstance(other, (list, tuple)):
to_concat = [self, *other]
else:
to_concat = [self, other]
return concat(
to_concat,
ignore_index=ignore_index,
verify_integrity=verify_integrity,
sort=sort,
)
def join(
self, other, on=None, how="left", lsuffix="", rsuffix="", sort=False
) -> "DataFrame":
"""
Join columns of another DataFrame.
Join columns with `other` DataFrame either on index or on a key
column. Efficiently join multiple DataFrame objects by index at once by
passing a list.
Parameters
----------
other : DataFrame, Series, or list of DataFrame
Index should be similar to one of the columns in this one. If a
Series is passed, its name attribute must be set, and that will be
used as the column name in the resulting joined DataFrame.
on : str, list of str, or array-like, optional
Column or index level name(s) in the caller to join on the index
in `other`, otherwise joins index-on-index. If multiple
values given, the `other` DataFrame must have a MultiIndex. Can
pass an array as the join key if it is not already contained in
the calling DataFrame. Like an Excel VLOOKUP operation.
how : {'left', 'right', 'outer', 'inner'}, default 'left'
How to handle the operation of the two objects.
* left: use calling frame's index (or column if on is specified)
* right: use `other`'s index.
* outer: form union of calling frame's index (or column if on is
specified) with `other`'s index, and sort it.
lexicographically.
* inner: form intersection of calling frame's index (or column if
on is specified) with `other`'s index, preserving the order
of the calling's one.
lsuffix : str, default ''
Suffix to use from left frame's overlapping columns.
rsuffix : str, default ''
Suffix to use from right frame's overlapping columns.
sort : bool, default False
Order result DataFrame lexicographically by the join key. If False,
the order of the join key depends on the join type (how keyword).
Returns
-------
DataFrame
A dataframe containing columns from both the caller and `other`.
See Also
--------
DataFrame.merge : For column(s)-on-columns(s) operations.
Notes
-----
Parameters `on`, `lsuffix`, and `rsuffix` are not supported when
passing a list of `DataFrame` objects.
Support for specifying index levels as the `on` parameter was added
in version 0.23.0.
Examples
--------
>>> df = pd.DataFrame({'key': ['K0', 'K1', 'K2', 'K3', 'K4', 'K5'],
... 'A': ['A0', 'A1', 'A2', 'A3', 'A4', 'A5']})
>>> df
key A
0 K0 A0
1 K1 A1
2 K2 A2
3 K3 A3
4 K4 A4
5 K5 A5
>>> other = pd.DataFrame({'key': ['K0', 'K1', 'K2'],
... 'B': ['B0', 'B1', 'B2']})
>>> other
key B
0 K0 B0
1 K1 B1
2 K2 B2
Join DataFrames using their indexes.
>>> df.join(other, lsuffix='_caller', rsuffix='_other')
key_caller A key_other B
0 K0 A0 K0 B0
1 K1 A1 K1 B1
2 K2 A2 K2 B2
3 K3 A3 NaN NaN
4 K4 A4 NaN NaN
5 K5 A5 NaN NaN
If we want to join using the key columns, we need to set key to be
the index in both `df` and `other`. The joined DataFrame will have
key as its index.
>>> df.set_index('key').join(other.set_index('key'))
A B
key
K0 A0 B0
K1 A1 B1
K2 A2 B2
K3 A3 NaN
K4 A4 NaN
K5 A5 NaN
Another option to join using the key columns is to use the `on`
parameter. DataFrame.join always uses `other`'s index but we can use
any column in `df`. This method preserves the original DataFrame's
index in the result.
>>> df.join(other.set_index('key'), on='key')
key A B
0 K0 A0 B0
1 K1 A1 B1
2 K2 A2 B2
3 K3 A3 NaN
4 K4 A4 NaN
5 K5 A5 NaN
"""
return self._join_compat(
other, on=on, how=how, lsuffix=lsuffix, rsuffix=rsuffix, sort=sort
)
def _join_compat(
self, other, on=None, how="left", lsuffix="", rsuffix="", sort=False
):
from pandas.core.reshape.merge import merge
from pandas.core.reshape.concat import concat
if isinstance(other, Series):
if other.name is None:
raise ValueError("Other Series must have a name")
other = DataFrame({other.name: other})
if isinstance(other, DataFrame):
return merge(
self,
other,
left_on=on,
how=how,
left_index=on is None,
right_index=True,
suffixes=(lsuffix, rsuffix),
sort=sort,
)
else:
if on is not None:
raise ValueError(
"Joining multiple DataFrames only supported for joining on index"
)
frames = [self] + list(other)
can_concat = all(df.index.is_unique for df in frames)
# join indexes only using concat
if can_concat:
if how == "left":
res = concat(
frames, axis=1, join="outer", verify_integrity=True, sort=sort
)
return res.reindex(self.index, copy=False)
else:
return concat(
frames, axis=1, join=how, verify_integrity=True, sort=sort
)
joined = frames[0]
for frame in frames[1:]:
joined = merge(
joined, frame, how=how, left_index=True, right_index=True
)
return joined
@Substitution("")
@Appender(_merge_doc, indents=2)
def merge(
self,
right,
how="inner",
on=None,
left_on=None,
right_on=None,
left_index=False,
right_index=False,
sort=False,
suffixes=("_x", "_y"),
copy=True,
indicator=False,
validate=None,
) -> "DataFrame":
from pandas.core.reshape.merge import merge
return merge(
self,
right,
how=how,
on=on,
left_on=left_on,
right_on=right_on,
left_index=left_index,
right_index=right_index,
sort=sort,
suffixes=suffixes,
copy=copy,
indicator=indicator,
validate=validate,
)
def round(self, decimals=0, *args, **kwargs) -> "DataFrame":
"""
Round a DataFrame to a variable number of decimal places.
Parameters
----------
decimals : int, dict, Series
Number of decimal places to round each column to. If an int is
given, round each column to the same number of places.
Otherwise dict and Series round to variable numbers of places.
Column names should be in the keys if `decimals` is a
dict-like, or in the index if `decimals` is a Series. Any
columns not included in `decimals` will be left as is. Elements
of `decimals` which are not columns of the input will be
ignored.
*args
Additional keywords have no effect but might be accepted for
compatibility with numpy.
**kwargs
Additional keywords have no effect but might be accepted for
compatibility with numpy.
Returns
-------
DataFrame
A DataFrame with the affected columns rounded to the specified
number of decimal places.
See Also
--------
numpy.around : Round a numpy array to the given number of decimals.
Series.round : Round a Series to the given number of decimals.
Examples
--------
>>> df = pd.DataFrame([(.21, .32), (.01, .67), (.66, .03), (.21, .18)],
... columns=['dogs', 'cats'])
>>> df
dogs cats
0 0.21 0.32
1 0.01 0.67
2 0.66 0.03
3 0.21 0.18
By providing an integer each column is rounded to the same number
of decimal places
>>> df.round(1)
dogs cats
0 0.2 0.3
1 0.0 0.7
2 0.7 0.0
3 0.2 0.2
With a dict, the number of places for specific columns can be
specified with the column names as key and the number of decimal
places as value
>>> df.round({'dogs': 1, 'cats': 0})
dogs cats
0 0.2 0.0
1 0.0 1.0
2 0.7 0.0
3 0.2 0.0
Using a Series, the number of places for specific columns can be
specified with the column names as index and the number of
decimal places as value
>>> decimals = pd.Series([0, 1], index=['cats', 'dogs'])
>>> df.round(decimals)
dogs cats
0 0.2 0.0
1 0.0 1.0
2 0.7 0.0
3 0.2 0.0
"""
from pandas.core.reshape.concat import concat
def _dict_round(df, decimals):
for col, vals in df.items():
try:
yield _series_round(vals, decimals[col])
except KeyError:
yield vals
def _series_round(s, decimals):
if is_integer_dtype(s) or is_float_dtype(s):
return s.round(decimals)
return s
nv.validate_round(args, kwargs)
if isinstance(decimals, (dict, Series)):
if isinstance(decimals, Series):
if not decimals.index.is_unique:
raise ValueError("Index of decimals must be unique")
new_cols = list(_dict_round(self, decimals))
elif is_integer(decimals):
# Dispatch to Series.round
new_cols = [_series_round(v, decimals) for _, v in self.items()]
else:
raise TypeError("decimals must be an integer, a dict-like or a Series")
if len(new_cols) > 0:
return self._constructor(
concat(new_cols, axis=1), index=self.index, columns=self.columns
)
else:
return self
# ----------------------------------------------------------------------
# Statistical methods, etc.
def corr(self, method="pearson", min_periods=1) -> "DataFrame":
"""
Compute pairwise correlation of columns, excluding NA/null values.
Parameters
----------
method : {'pearson', 'kendall', 'spearman'} or callable
Method of correlation:
* pearson : standard correlation coefficient
* kendall : Kendall Tau correlation coefficient
* spearman : Spearman rank correlation
* callable: callable with input two 1d ndarrays
and returning a float. Note that the returned matrix from corr
will have 1 along the diagonals and will be symmetric
regardless of the callable's behavior.
.. versionadded:: 0.24.0
min_periods : int, optional
Minimum number of observations required per pair of columns
to have a valid result. Currently only available for Pearson
and Spearman correlation.
Returns
-------
DataFrame
Correlation matrix.
See Also
--------
DataFrame.corrwith : Compute pairwise correlation with another
DataFrame or Series.
Series.corr : Compute the correlation between two Series.
Examples
--------
>>> def histogram_intersection(a, b):
... v = np.minimum(a, b).sum().round(decimals=1)
... return v
>>> df = pd.DataFrame([(.2, .3), (.0, .6), (.6, .0), (.2, .1)],
... columns=['dogs', 'cats'])
>>> df.corr(method=histogram_intersection)
dogs cats
dogs 1.0 0.3
cats 0.3 1.0
"""
numeric_df = self._get_numeric_data()
cols = numeric_df.columns
idx = cols.copy()
mat = numeric_df.values
if method == "pearson":
correl = libalgos.nancorr(ensure_float64(mat), minp=min_periods)
elif method == "spearman":
correl = libalgos.nancorr_spearman(ensure_float64(mat), minp=min_periods)
elif method == "kendall" or callable(method):
if min_periods is None:
min_periods = 1
mat = ensure_float64(mat).T
corrf = nanops.get_corr_func(method)
K = len(cols)
correl = np.empty((K, K), dtype=float)
mask = np.isfinite(mat)
for i, ac in enumerate(mat):
for j, bc in enumerate(mat):
if i > j:
continue
valid = mask[i] & mask[j]
if valid.sum() < min_periods:
c = np.nan
elif i == j:
c = 1.0
elif not valid.all():
c = corrf(ac[valid], bc[valid])
else:
c = corrf(ac, bc)
correl[i, j] = c
correl[j, i] = c
else:
raise ValueError(
"method must be either 'pearson', "
"'spearman', 'kendall', or a callable, "
f"'{method}' was supplied"
)
return self._constructor(correl, index=idx, columns=cols)
def cov(self, min_periods=None) -> "DataFrame":
"""
Compute pairwise covariance of columns, excluding NA/null values.
Compute the pairwise covariance among the series of a DataFrame.
The returned data frame is the `covariance matrix
<https://en.wikipedia.org/wiki/Covariance_matrix>`__ of the columns
of the DataFrame.
Both NA and null values are automatically excluded from the
calculation. (See the note below about bias from missing values.)
A threshold can be set for the minimum number of
observations for each value created. Comparisons with observations
below this threshold will be returned as ``NaN``.
This method is generally used for the analysis of time series data to
understand the relationship between different measures
across time.
Parameters
----------
min_periods : int, optional
Minimum number of observations required per pair of columns
to have a valid result.
Returns
-------
DataFrame
The covariance matrix of the series of the DataFrame.
See Also
--------
Series.cov : Compute covariance with another Series.
core.window.EWM.cov: Exponential weighted sample covariance.
core.window.Expanding.cov : Expanding sample covariance.
core.window.Rolling.cov : Rolling sample covariance.
Notes
-----
Returns the covariance matrix of the DataFrame's time series.
The covariance is normalized by N-1.
For DataFrames that have Series that are missing data (assuming that
data is `missing at random
<https://en.wikipedia.org/wiki/Missing_data#Missing_at_random>`__)
the returned covariance matrix will be an unbiased estimate
of the variance and covariance between the member Series.
However, for many applications this estimate may not be acceptable
because the estimate covariance matrix is not guaranteed to be positive
semi-definite. This could lead to estimate correlations having
absolute values which are greater than one, and/or a non-invertible
covariance matrix. See `Estimation of covariance matrices
<https://en.wikipedia.org/w/index.php?title=Estimation_of_covariance_
matrices>`__ for more details.
Examples
--------
>>> df = pd.DataFrame([(1, 2), (0, 3), (2, 0), (1, 1)],
... columns=['dogs', 'cats'])
>>> df.cov()
dogs cats
dogs 0.666667 -1.000000
cats -1.000000 1.666667
>>> np.random.seed(42)
>>> df = pd.DataFrame(np.random.randn(1000, 5),
... columns=['a', 'b', 'c', 'd', 'e'])
>>> df.cov()
a b c d e
a 0.998438 -0.020161 0.059277 -0.008943 0.014144
b -0.020161 1.059352 -0.008543 -0.024738 0.009826
c 0.059277 -0.008543 1.010670 -0.001486 -0.000271
d -0.008943 -0.024738 -0.001486 0.921297 -0.013692
e 0.014144 0.009826 -0.000271 -0.013692 0.977795
**Minimum number of periods**
This method also supports an optional ``min_periods`` keyword
that specifies the required minimum number of non-NA observations for
each column pair in order to have a valid result:
>>> np.random.seed(42)
>>> df = pd.DataFrame(np.random.randn(20, 3),
... columns=['a', 'b', 'c'])
>>> df.loc[df.index[:5], 'a'] = np.nan
>>> df.loc[df.index[5:10], 'b'] = np.nan
>>> df.cov(min_periods=12)
a b c
a 0.316741 NaN -0.150812
b NaN 1.248003 0.191417
c -0.150812 0.191417 0.895202
"""
numeric_df = self._get_numeric_data()
cols = numeric_df.columns
idx = cols.copy()
mat = numeric_df.values
if notna(mat).all():
if min_periods is not None and min_periods > len(mat):
baseCov = np.empty((mat.shape[1], mat.shape[1]))
baseCov.fill(np.nan)
else:
baseCov = np.cov(mat.T)
baseCov = baseCov.reshape((len(cols), len(cols)))
else:
baseCov = libalgos.nancorr(ensure_float64(mat), cov=True, minp=min_periods)
return self._constructor(baseCov, index=idx, columns=cols)
def corrwith(self, other, axis=0, drop=False, method="pearson") -> Series:
"""
Compute pairwise correlation.
Pairwise correlation is computed between rows or columns of
DataFrame with rows or columns of Series or DataFrame. DataFrames
are first aligned along both axes before computing the
correlations.
Parameters
----------
other : DataFrame, Series
Object with which to compute correlations.
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to use. 0 or 'index' to compute column-wise, 1 or 'columns' for
row-wise.
drop : bool, default False
Drop missing indices from result.
method : {'pearson', 'kendall', 'spearman'} or callable
Method of correlation:
* pearson : standard correlation coefficient
* kendall : Kendall Tau correlation coefficient
* spearman : Spearman rank correlation
* callable: callable with input two 1d ndarrays
and returning a float.
.. versionadded:: 0.24.0
Returns
-------
Series
Pairwise correlations.
See Also
--------
DataFrame.corr : Compute pairwise correlation of columns.
"""
axis = self._get_axis_number(axis)
this = self._get_numeric_data()
if isinstance(other, Series):
return this.apply(lambda x: other.corr(x, method=method), axis=axis)
other = other._get_numeric_data()
left, right = this.align(other, join="inner", copy=False)
if axis == 1:
left = left.T
right = right.T
if method == "pearson":
# mask missing values
left = left + right * 0
right = right + left * 0
# demeaned data
ldem = left - left.mean()
rdem = right - right.mean()
num = (ldem * rdem).sum()
dom = (left.count() - 1) * left.std() * right.std()
correl = num / dom
elif method in ["kendall", "spearman"] or callable(method):
def c(x):
return nanops.nancorr(x[0], x[1], method=method)
correl = Series(
map(c, zip(left.values.T, right.values.T)), index=left.columns
)
else:
raise ValueError(
f"Invalid method {method} was passed, "
"valid methods are: 'pearson', 'kendall', "
"'spearman', or callable"
)
if not drop:
# Find non-matching labels along the given axis
# and append missing correlations (GH 22375)
raxis = 1 if axis == 0 else 0
result_index = this._get_axis(raxis).union(other._get_axis(raxis))
idx_diff = result_index.difference(correl.index)
if len(idx_diff) > 0:
correl = correl.append(Series([np.nan] * len(idx_diff), index=idx_diff))
return correl
# ----------------------------------------------------------------------
# ndarray-like stats methods
def count(self, axis=0, level=None, numeric_only=False):
"""
Count non-NA cells for each column or row.
The values `None`, `NaN`, `NaT`, and optionally `numpy.inf` (depending
on `pandas.options.mode.use_inf_as_na`) are considered NA.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
If 0 or 'index' counts are generated for each column.
If 1 or 'columns' counts are generated for each **row**.
level : int or str, optional
If the axis is a `MultiIndex` (hierarchical), count along a
particular `level`, collapsing into a `DataFrame`.
A `str` specifies the level name.
numeric_only : bool, default False
Include only `float`, `int` or `boolean` data.
Returns
-------
Series or DataFrame
For each column/row the number of non-NA/null entries.
If `level` is specified returns a `DataFrame`.
See Also
--------
Series.count: Number of non-NA elements in a Series.
DataFrame.shape: Number of DataFrame rows and columns (including NA
elements).
DataFrame.isna: Boolean same-sized DataFrame showing places of NA
elements.
Examples
--------
Constructing DataFrame from a dictionary:
>>> df = pd.DataFrame({"Person":
... ["John", "Myla", "Lewis", "John", "Myla"],
... "Age": [24., np.nan, 21., 33, 26],
... "Single": [False, True, True, True, False]})
>>> df
Person Age Single
0 John 24.0 False
1 Myla NaN True
2 Lewis 21.0 True
3 John 33.0 True
4 Myla 26.0 False
Notice the uncounted NA values:
>>> df.count()
Person 5
Age 4
Single 5
dtype: int64
Counts for each **row**:
>>> df.count(axis='columns')
0 3
1 2
2 3
3 3
4 3
dtype: int64
Counts for one level of a `MultiIndex`:
>>> df.set_index(["Person", "Single"]).count(level="Person")
Age
Person
John 2
Lewis 1
Myla 1
"""
axis = self._get_axis_number(axis)
if level is not None:
return self._count_level(level, axis=axis, numeric_only=numeric_only)
if numeric_only:
frame = self._get_numeric_data()
else:
frame = self
# GH #423
if len(frame._get_axis(axis)) == 0:
result = Series(0, index=frame._get_agg_axis(axis))
else:
if frame._is_mixed_type or frame._data.any_extension_types:
# the or any_extension_types is really only hit for single-
# column frames with an extension array
result = notna(frame).sum(axis=axis)
else:
# GH13407
series_counts = notna(frame).sum(axis=axis)
counts = series_counts.values
result = Series(counts, index=frame._get_agg_axis(axis))
return result.astype("int64")
def _count_level(self, level, axis=0, numeric_only=False):
if numeric_only:
frame = self._get_numeric_data()
else:
frame = self
count_axis = frame._get_axis(axis)
agg_axis = frame._get_agg_axis(axis)
if not isinstance(count_axis, ABCMultiIndex):
raise TypeError(
f"Can only count levels on hierarchical {self._get_axis_name(axis)}."
)
if frame._is_mixed_type:
# Since we have mixed types, calling notna(frame.values) might
# upcast everything to object
mask = notna(frame).values
else:
# But use the speedup when we have homogeneous dtypes
mask = notna(frame.values)
if axis == 1:
# We're transposing the mask rather than frame to avoid potential
# upcasts to object, which induces a ~20x slowdown
mask = mask.T
if isinstance(level, str):
level = count_axis._get_level_number(level)
level_name = count_axis._names[level]
level_index = count_axis.levels[level]._shallow_copy(name=level_name)
level_codes = ensure_int64(count_axis.codes[level])
counts = lib.count_level_2d(mask, level_codes, len(level_index), axis=0)
result = DataFrame(counts, index=level_index, columns=agg_axis)
if axis == 1:
# Undo our earlier transpose
return result.T
else:
return result
def _reduce(
self, op, name, axis=0, skipna=True, numeric_only=None, filter_type=None, **kwds
):
assert filter_type is None or filter_type == "bool", filter_type
dtype_is_dt = self.dtypes.apply(
lambda x: is_datetime64_any_dtype(x) or is_period_dtype(x)
)
if numeric_only is None and name in ["mean", "median"] and dtype_is_dt.any():
warnings.warn(
"DataFrame.mean and DataFrame.median with numeric_only=None "
"will include datetime64, datetime64tz, and PeriodDtype columns in a "
"future version.",
FutureWarning,
stacklevel=3,
)
cols = self.columns[~dtype_is_dt]
self = self[cols]
if axis is None and filter_type == "bool":
labels = None
constructor = None
else:
# TODO: Make other agg func handle axis=None properly
axis = self._get_axis_number(axis)
labels = self._get_agg_axis(axis)
constructor = self._constructor
def f(x):
return op(x, axis=axis, skipna=skipna, **kwds)
def _get_data(axis_matters):
if filter_type is None:
data = self._get_numeric_data()
elif filter_type == "bool":
if axis_matters:
# GH#25101, GH#24434
data = self._get_bool_data() if axis == 0 else self
else:
data = self._get_bool_data()
else: # pragma: no cover
msg = (
f"Generating numeric_only data with filter_type {filter_type} "
"not supported."
)
raise NotImplementedError(msg)
return data
if numeric_only is not None and axis in [0, 1]:
df = self
if numeric_only is True:
df = _get_data(axis_matters=True)
if axis == 1:
df = df.T
axis = 0
out_dtype = "bool" if filter_type == "bool" else None
def blk_func(values):
if values.ndim == 1 and not isinstance(values, np.ndarray):
# we can't pass axis=1
return op(values, axis=0, skipna=skipna, **kwds)
return op(values, axis=1, skipna=skipna, **kwds)
# After possibly _get_data and transposing, we are now in the
# simple case where we can use BlockManager._reduce
res = df._data.reduce(blk_func)
assert isinstance(res, dict)
if len(res):
assert len(res) == max(list(res.keys())) + 1, res.keys()
out = df._constructor_sliced(res, index=range(len(res)), dtype=out_dtype)
out.index = df.columns
if axis == 0 and df.dtypes.apply(needs_i8_conversion).any():
# FIXME: needs_i8_conversion check is kludge, not sure
# why it is necessary in this case and this case alone
out[:] = coerce_to_dtypes(out.values, df.dtypes)
return out
if numeric_only is None:
data = self
values = data.values
try:
result = f(values)
except TypeError:
# e.g. in nanops trying to convert strs to float
# try by-column first
if filter_type is None and axis == 0:
# this can end up with a non-reduction
# but not always. if the types are mixed
# with datelike then need to make sure a series
# we only end up here if we have not specified
# numeric_only and yet we have tried a
# column-by-column reduction, where we have mixed type.
# So let's just do what we can
from pandas.core.apply import frame_apply
opa = frame_apply(
self, func=f, result_type="expand", ignore_failures=True
)
result = opa.get_result()
if result.ndim == self.ndim:
result = result.iloc[0]
return result
# TODO: why doesnt axis matter here?
data = _get_data(axis_matters=False)
labels = data._get_agg_axis(axis)
values = data.values
with np.errstate(all="ignore"):
result = f(values)
else:
if numeric_only:
data = _get_data(axis_matters=True)
labels = data._get_agg_axis(axis)
values = data.values
else:
data = self
values = data.values
result = f(values)
if filter_type == "bool" and is_object_dtype(values) and axis is None:
# work around https://github.com/numpy/numpy/issues/10489
# TODO: can we de-duplicate parts of this with the next blocK?
result = np.bool_(result)
elif hasattr(result, "dtype") and is_object_dtype(result.dtype):
try:
if filter_type is None:
result = result.astype(np.float64)
elif filter_type == "bool" and notna(result).all():
result = result.astype(np.bool_)
except (ValueError, TypeError):
# try to coerce to the original dtypes item by item if we can
if axis == 0:
result = coerce_to_dtypes(result, data.dtypes)
if constructor is not None:
result = self._constructor_sliced(result, index=labels)
return result
def nunique(self, axis=0, dropna=True) -> Series:
"""
Count distinct observations over requested axis.
Return Series with number of distinct observations. Can ignore NaN
values.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to use. 0 or 'index' for row-wise, 1 or 'columns' for
column-wise.
dropna : bool, default True
Don't include NaN in the counts.
Returns
-------
Series
See Also
--------
Series.nunique: Method nunique for Series.
DataFrame.count: Count non-NA cells for each column or row.
Examples
--------
>>> df = pd.DataFrame({'A': [1, 2, 3], 'B': [1, 1, 1]})
>>> df.nunique()
A 3
B 1
dtype: int64
>>> df.nunique(axis=1)
0 1
1 2
2 2
dtype: int64
"""
return self.apply(Series.nunique, axis=axis, dropna=dropna)
def idxmin(self, axis=0, skipna=True) -> Series:
"""
Return index of first occurrence of minimum over requested axis.
NA/null values are excluded.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to use. 0 or 'index' for row-wise, 1 or 'columns' for column-wise.
skipna : bool, default True
Exclude NA/null values. If an entire row/column is NA, the result
will be NA.
Returns
-------
Series
Indexes of minima along the specified axis.
Raises
------
ValueError
* If the row/column is empty
See Also
--------
Series.idxmin : Return index of the minimum element.
Notes
-----
This method is the DataFrame version of ``ndarray.argmin``.
Examples
--------
Consider a dataset containing food consumption in Argentina.
>>> df = pd.DataFrame({'consumption': [10.51, 103.11, 55.48],
... 'co2_emissions': [37.2, 19.66, 1712]},
... index=['Pork', 'Wheat Products', 'Beef'])
>>> df
consumption co2_emissions
Pork 10.51 37.20
Wheat Products 103.11 19.66
Beef 55.48 1712.00
By default, it returns the index for the minimum value in each column.
>>> df.idxmin()
consumption Pork
co2_emissions Wheat Products
dtype: object
To return the index for the minimum value in each row, use ``axis="columns"``.
>>> df.idxmin(axis="columns")
Pork consumption
Wheat Products co2_emissions
Beef consumption
dtype: object
"""
axis = self._get_axis_number(axis)
indices = nanops.nanargmin(self.values, axis=axis, skipna=skipna)
index = self._get_axis(axis)
result = [index[i] if i >= 0 else np.nan for i in indices]
return Series(result, index=self._get_agg_axis(axis))
def idxmax(self, axis=0, skipna=True) -> Series:
"""
Return index of first occurrence of maximum over requested axis.
NA/null values are excluded.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to use. 0 or 'index' for row-wise, 1 or 'columns' for column-wise.
skipna : bool, default True
Exclude NA/null values. If an entire row/column is NA, the result
will be NA.
Returns
-------
Series
Indexes of maxima along the specified axis.
Raises
------
ValueError
* If the row/column is empty
See Also
--------
Series.idxmax : Return index of the maximum element.
Notes
-----
This method is the DataFrame version of ``ndarray.argmax``.
Examples
--------
Consider a dataset containing food consumption in Argentina.
>>> df = pd.DataFrame({'consumption': [10.51, 103.11, 55.48],
... 'co2_emissions': [37.2, 19.66, 1712]},
... index=['Pork', 'Wheat Products', 'Beef'])
>>> df
consumption co2_emissions
Pork 10.51 37.20
Wheat Products 103.11 19.66
Beef 55.48 1712.00
By default, it returns the index for the maximum value in each column.
>>> df.idxmax()
consumption Wheat Products
co2_emissions Beef
dtype: object
To return the index for the maximum value in each row, use ``axis="columns"``.
>>> df.idxmax(axis="columns")
Pork co2_emissions
Wheat Products consumption
Beef co2_emissions
dtype: object
"""
axis = self._get_axis_number(axis)
indices = nanops.nanargmax(self.values, axis=axis, skipna=skipna)
index = self._get_axis(axis)
result = [index[i] if i >= 0 else np.nan for i in indices]
return Series(result, index=self._get_agg_axis(axis))
def _get_agg_axis(self, axis_num):
"""
Let's be explicit about this.
"""
if axis_num == 0:
return self.columns
elif axis_num == 1:
return self.index
else:
raise ValueError(f"Axis must be 0 or 1 (got {repr(axis_num)})")
def mode(self, axis=0, numeric_only=False, dropna=True) -> "DataFrame":
"""
Get the mode(s) of each element along the selected axis.
The mode of a set of values is the value that appears most often.
It can be multiple values.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to iterate over while searching for the mode:
* 0 or 'index' : get mode of each column
* 1 or 'columns' : get mode of each row.
numeric_only : bool, default False
If True, only apply to numeric columns.
dropna : bool, default True
Don't consider counts of NaN/NaT.
.. versionadded:: 0.24.0
Returns
-------
DataFrame
The modes of each column or row.
See Also
--------
Series.mode : Return the highest frequency value in a Series.
Series.value_counts : Return the counts of values in a Series.
Examples
--------
>>> df = pd.DataFrame([('bird', 2, 2),
... ('mammal', 4, np.nan),
... ('arthropod', 8, 0),
... ('bird', 2, np.nan)],
... index=('falcon', 'horse', 'spider', 'ostrich'),
... columns=('species', 'legs', 'wings'))
>>> df
species legs wings
falcon bird 2 2.0
horse mammal 4 NaN
spider arthropod 8 0.0
ostrich bird 2 NaN
By default, missing values are not considered, and the mode of wings
are both 0 and 2. The second row of species and legs contains ``NaN``,
because they have only one mode, but the DataFrame has two rows.
>>> df.mode()
species legs wings
0 bird 2.0 0.0
1 NaN NaN 2.0
Setting ``dropna=False`` ``NaN`` values are considered and they can be
the mode (like for wings).
>>> df.mode(dropna=False)
species legs wings
0 bird 2 NaN
Setting ``numeric_only=True``, only the mode of numeric columns is
computed, and columns of other types are ignored.
>>> df.mode(numeric_only=True)
legs wings
0 2.0 0.0
1 NaN 2.0
To compute the mode over columns and not rows, use the axis parameter:
>>> df.mode(axis='columns', numeric_only=True)
0 1
falcon 2.0 NaN
horse 4.0 NaN
spider 0.0 8.0
ostrich 2.0 NaN
"""
data = self if not numeric_only else self._get_numeric_data()
def f(s):
return s.mode(dropna=dropna)
return data.apply(f, axis=axis)
def quantile(self, q=0.5, axis=0, numeric_only=True, interpolation="linear"):
"""
Return values at the given quantile over requested axis.
Parameters
----------
q : float or array-like, default 0.5 (50% quantile)
Value between 0 <= q <= 1, the quantile(s) to compute.
axis : {0, 1, 'index', 'columns'} (default 0)
Equals 0 or 'index' for row-wise, 1 or 'columns' for column-wise.
numeric_only : bool, default True
If False, the quantile of datetime and timedelta data will be
computed as well.
interpolation : {'linear', 'lower', 'higher', 'midpoint', 'nearest'}
This optional parameter specifies the interpolation method to use,
when the desired quantile lies between two data points `i` and `j`:
* linear: `i + (j - i) * fraction`, where `fraction` is the
fractional part of the index surrounded by `i` and `j`.
* lower: `i`.
* higher: `j`.
* nearest: `i` or `j` whichever is nearest.
* midpoint: (`i` + `j`) / 2.
Returns
-------
Series or DataFrame
If ``q`` is an array, a DataFrame will be returned where the
index is ``q``, the columns are the columns of self, and the
values are the quantiles.
If ``q`` is a float, a Series will be returned where the
index is the columns of self and the values are the quantiles.
See Also
--------
core.window.Rolling.quantile: Rolling quantile.
numpy.percentile: Numpy function to compute the percentile.
Examples
--------
>>> df = pd.DataFrame(np.array([[1, 1], [2, 10], [3, 100], [4, 100]]),
... columns=['a', 'b'])
>>> df.quantile(.1)
a 1.3
b 3.7
Name: 0.1, dtype: float64
>>> df.quantile([.1, .5])
a b
0.1 1.3 3.7
0.5 2.5 55.0
Specifying `numeric_only=False` will also compute the quantile of
datetime and timedelta data.
>>> df = pd.DataFrame({'A': [1, 2],
... 'B': [pd.Timestamp('2010'),
... pd.Timestamp('2011')],
... 'C': [pd.Timedelta('1 days'),
... pd.Timedelta('2 days')]})
>>> df.quantile(0.5, numeric_only=False)
A 1.5
B 2010-07-02 12:00:00
C 1 days 12:00:00
Name: 0.5, dtype: object
"""
validate_percentile(q)
data = self._get_numeric_data() if numeric_only else self
axis = self._get_axis_number(axis)
is_transposed = axis == 1
if is_transposed:
data = data.T
if len(data.columns) == 0:
# GH#23925 _get_numeric_data may have dropped all columns
cols = Index([], name=self.columns.name)
if is_list_like(q):
return self._constructor([], index=q, columns=cols)
return self._constructor_sliced([], index=cols, name=q, dtype=np.float64)
result = data._data.quantile(
qs=q, axis=1, interpolation=interpolation, transposed=is_transposed
)
if result.ndim == 2:
result = self._constructor(result)
else:
result = self._constructor_sliced(result, name=q)
if is_transposed:
result = result.T
return result
def to_timestamp(
self, freq=None, how: str = "start", axis: Axis = 0, copy: bool = True
) -> "DataFrame":
"""
Cast to DatetimeIndex of timestamps, at *beginning* of period.
Parameters
----------
freq : str, default frequency of PeriodIndex
Desired frequency.
how : {'s', 'e', 'start', 'end'}
Convention for converting period to timestamp; start of period
vs. end.
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to convert (the index by default).
copy : bool, default True
If False then underlying input data is not copied.
Returns
-------
DataFrame with DatetimeIndex
"""
new_obj = self.copy(deep=copy)
axis_name = self._get_axis_name(axis)
old_ax = getattr(self, axis_name)
new_ax = old_ax.to_timestamp(freq=freq, how=how)
setattr(new_obj, axis_name, new_ax)
return new_obj
def to_period(self, freq=None, axis: Axis = 0, copy: bool = True) -> "DataFrame":
"""
Convert DataFrame from DatetimeIndex to PeriodIndex.
Convert DataFrame from DatetimeIndex to PeriodIndex with desired
frequency (inferred from index if not passed).
Parameters
----------
freq : str, default
Frequency of the PeriodIndex.
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to convert (the index by default).
copy : bool, default True
If False then underlying input data is not copied.
Returns
-------
DataFrame with PeriodIndex
"""
new_obj = self.copy(deep=copy)
axis_name = self._get_axis_name(axis)
old_ax = getattr(self, axis_name)
new_ax = old_ax.to_period(freq=freq)
setattr(new_obj, axis_name, new_ax)
return new_obj
def isin(self, values) -> "DataFrame":
"""
Whether each element in the DataFrame is contained in values.
Parameters
----------
values : iterable, Series, DataFrame or dict
The result will only be true at a location if all the
labels match. If `values` is a Series, that's the index. If
`values` is a dict, the keys must be the column names,
which must match. If `values` is a DataFrame,
then both the index and column labels must match.
Returns
-------
DataFrame
DataFrame of booleans showing whether each element in the DataFrame
is contained in values.
See Also
--------
DataFrame.eq: Equality test for DataFrame.
Series.isin: Equivalent method on Series.
Series.str.contains: Test if pattern or regex is contained within a
string of a Series or Index.
Examples
--------
>>> df = pd.DataFrame({'num_legs': [2, 4], 'num_wings': [2, 0]},
... index=['falcon', 'dog'])
>>> df
num_legs num_wings
falcon 2 2
dog 4 0
When ``values`` is a list check whether every value in the DataFrame
is present in the list (which animals have 0 or 2 legs or wings)
>>> df.isin([0, 2])
num_legs num_wings
falcon True True
dog False True
When ``values`` is a dict, we can pass values to check for each
column separately:
>>> df.isin({'num_wings': [0, 3]})
num_legs num_wings
falcon False False
dog False True
When ``values`` is a Series or DataFrame the index and column must
match. Note that 'falcon' does not match based on the number of legs
in df2.
>>> other = pd.DataFrame({'num_legs': [8, 2], 'num_wings': [0, 2]},
... index=['spider', 'falcon'])
>>> df.isin(other)
num_legs num_wings
falcon True True
dog False False
"""
if isinstance(values, dict):
from pandas.core.reshape.concat import concat
values = collections.defaultdict(list, values)
return concat(
(
self.iloc[:, [i]].isin(values[col])
for i, col in enumerate(self.columns)
),
axis=1,
)
elif isinstance(values, Series):
if not values.index.is_unique:
raise ValueError("cannot compute isin with a duplicate axis.")
return self.eq(values.reindex_like(self), axis="index")
elif isinstance(values, DataFrame):
if not (values.columns.is_unique and values.index.is_unique):
raise ValueError("cannot compute isin with a duplicate axis.")
return self.eq(values.reindex_like(self))
else:
if not is_list_like(values):
raise TypeError(
"only list-like or dict-like objects are allowed "
"to be passed to DataFrame.isin(), "
f"you passed a '{type(values).__name__}'"
)
return DataFrame(
algorithms.isin(self.values.ravel(), values).reshape(self.shape),
self.index,
self.columns,
)
# ----------------------------------------------------------------------
# Add index and columns
_AXIS_ORDERS = ["index", "columns"]
_AXIS_NUMBERS = {"index": 0, "columns": 1}
_AXIS_NAMES = {0: "index", 1: "columns"}
_AXIS_REVERSED = True
_AXIS_LEN = len(_AXIS_ORDERS)
_info_axis_number = 1
_info_axis_name = "columns"
index: "Index" = properties.AxisProperty(
axis=1, doc="The index (row labels) of the DataFrame."
)
columns: "Index" = properties.AxisProperty(
axis=0, doc="The column labels of the DataFrame."
)
# ----------------------------------------------------------------------
# Add plotting methods to DataFrame
plot = CachedAccessor("plot", pandas.plotting.PlotAccessor)
hist = pandas.plotting.hist_frame
boxplot = pandas.plotting.boxplot_frame
sparse = CachedAccessor("sparse", SparseFrameAccessor)
DataFrame._add_numeric_operations()
DataFrame._add_series_or_dataframe_operations()
ops.add_flex_arithmetic_methods(DataFrame)
ops.add_special_arithmetic_methods(DataFrame)
def _from_nested_dict(data):
# TODO: this should be seriously cythonized
new_data = collections.defaultdict(dict)
for index, s in data.items():
for col, v in s.items():
new_data[col][index] = v
return new_data
| BugsInPy/BugsInPy/temp/projects/pandas/bug-47-fixed/pandas/pandas/core/frame.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-47-buggy/pandas/pandas/core/frame.py |
pandas-bug-129 | from datetime import datetime, timedelta
import operator
from typing import Any, Sequence, Type, Union, cast
import warnings
import numpy as np
from pandas._libs import NaT, NaTType, Timestamp, algos, iNaT, lib
from pandas._libs.tslibs.c_timestamp import maybe_integer_op_deprecated
from pandas._libs.tslibs.period import DIFFERENT_FREQ, IncompatibleFrequency, Period
from pandas._libs.tslibs.timedeltas import Timedelta, delta_to_nanoseconds
from pandas._libs.tslibs.timestamps import RoundTo, round_nsint64
from pandas.compat.numpy import function as nv
from pandas.errors import AbstractMethodError, NullFrequencyError, PerformanceWarning
from pandas.util._decorators import Appender, Substitution
from pandas.util._validators import validate_fillna_kwargs
from pandas.core.dtypes.common import (
is_categorical_dtype,
is_datetime64_any_dtype,
is_datetime64_dtype,
is_datetime64tz_dtype,
is_datetime_or_timedelta_dtype,
is_dtype_equal,
is_float_dtype,
is_integer_dtype,
is_list_like,
is_object_dtype,
is_offsetlike,
is_period_dtype,
is_string_dtype,
is_timedelta64_dtype,
is_unsigned_integer_dtype,
pandas_dtype,
)
from pandas.core.dtypes.generic import (
ABCDataFrame,
ABCIndexClass,
ABCPeriodArray,
ABCSeries,
)
from pandas.core.dtypes.inference import is_array_like
from pandas.core.dtypes.missing import is_valid_nat_for_dtype, isna
from pandas._typing import DatetimeLikeScalar
from pandas.core import missing, nanops
from pandas.core.algorithms import checked_add_with_arr, take, unique1d, value_counts
import pandas.core.common as com
from pandas.core.ops.invalid import make_invalid_op
from pandas.tseries import frequencies
from pandas.tseries.offsets import DateOffset, Tick
from .base import ExtensionArray, ExtensionOpsMixin
class AttributesMixin:
_data = None # type: np.ndarray
@classmethod
def _simple_new(cls, values, **kwargs):
raise AbstractMethodError(cls)
@property
def _scalar_type(self) -> Type[DatetimeLikeScalar]:
"""The scalar associated with this datelike
* PeriodArray : Period
* DatetimeArray : Timestamp
* TimedeltaArray : Timedelta
"""
raise AbstractMethodError(self)
def _scalar_from_string(
self, value: str
) -> Union[Period, Timestamp, Timedelta, NaTType]:
"""
Construct a scalar type from a string.
Parameters
----------
value : str
Returns
-------
Period, Timestamp, or Timedelta, or NaT
Whatever the type of ``self._scalar_type`` is.
Notes
-----
This should call ``self._check_compatible_with`` before
unboxing the result.
"""
raise AbstractMethodError(self)
def _unbox_scalar(self, value: Union[Period, Timestamp, Timedelta, NaTType]) -> int:
"""
Unbox the integer value of a scalar `value`.
Parameters
----------
value : Union[Period, Timestamp, Timedelta]
Returns
-------
int
Examples
--------
>>> self._unbox_scalar(Timedelta('10s')) # DOCTEST: +SKIP
10000000000
"""
raise AbstractMethodError(self)
def _check_compatible_with(
self, other: Union[Period, Timestamp, Timedelta, NaTType]
) -> None:
"""
Verify that `self` and `other` are compatible.
* DatetimeArray verifies that the timezones (if any) match
* PeriodArray verifies that the freq matches
* Timedelta has no verification
In each case, NaT is considered compatible.
Parameters
----------
other
Raises
------
Exception
"""
raise AbstractMethodError(self)
class DatelikeOps:
"""
Common ops for DatetimeIndex/PeriodIndex, but not TimedeltaIndex.
"""
@Substitution(
URL="https://docs.python.org/3/library/datetime.html"
"#strftime-and-strptime-behavior"
)
def strftime(self, date_format):
"""
Convert to Index using specified date_format.
Return an Index of formatted strings specified by date_format, which
supports the same string format as the python standard library. Details
of the string format can be found in `python string format
doc <%(URL)s>`__.
Parameters
----------
date_format : str
Date format string (e.g. "%%Y-%%m-%%d").
Returns
-------
ndarray
NumPy ndarray of formatted strings.
See Also
--------
to_datetime : Convert the given argument to datetime.
DatetimeIndex.normalize : Return DatetimeIndex with times to midnight.
DatetimeIndex.round : Round the DatetimeIndex to the specified freq.
DatetimeIndex.floor : Floor the DatetimeIndex to the specified freq.
Examples
--------
>>> rng = pd.date_range(pd.Timestamp("2018-03-10 09:00"),
... periods=3, freq='s')
>>> rng.strftime('%%B %%d, %%Y, %%r')
Index(['March 10, 2018, 09:00:00 AM', 'March 10, 2018, 09:00:01 AM',
'March 10, 2018, 09:00:02 AM'],
dtype='object')
"""
return self._format_native_types(date_format=date_format).astype(object)
class TimelikeOps:
"""
Common ops for TimedeltaIndex/DatetimeIndex, but not PeriodIndex.
"""
_round_doc = """
Perform {op} operation on the data to the specified `freq`.
Parameters
----------
freq : str or Offset
The frequency level to {op} the index to. Must be a fixed
frequency like 'S' (second) not 'ME' (month end). See
:ref:`frequency aliases <timeseries.offset_aliases>` for
a list of possible `freq` values.
ambiguous : 'infer', bool-ndarray, 'NaT', default 'raise'
Only relevant for DatetimeIndex:
- 'infer' will attempt to infer fall dst-transition hours based on
order
- bool-ndarray where True signifies a DST time, False designates
a non-DST time (note that this flag is only applicable for
ambiguous times)
- 'NaT' will return NaT where there are ambiguous times
- 'raise' will raise an AmbiguousTimeError if there are ambiguous
times.
.. versionadded:: 0.24.0
nonexistent : 'shift_forward', 'shift_backward', 'NaT', timedelta, \
default 'raise'
A nonexistent time does not exist in a particular timezone
where clocks moved forward due to DST.
- 'shift_forward' will shift the nonexistent time forward to the
closest existing time
- 'shift_backward' will shift the nonexistent time backward to the
closest existing time
- 'NaT' will return NaT where there are nonexistent times
- timedelta objects will shift nonexistent times by the timedelta
- 'raise' will raise an NonExistentTimeError if there are
nonexistent times.
.. versionadded:: 0.24.0
Returns
-------
DatetimeIndex, TimedeltaIndex, or Series
Index of the same type for a DatetimeIndex or TimedeltaIndex,
or a Series with the same index for a Series.
Raises
------
ValueError if the `freq` cannot be converted.
Examples
--------
**DatetimeIndex**
>>> rng = pd.date_range('1/1/2018 11:59:00', periods=3, freq='min')
>>> rng
DatetimeIndex(['2018-01-01 11:59:00', '2018-01-01 12:00:00',
'2018-01-01 12:01:00'],
dtype='datetime64[ns]', freq='T')
"""
_round_example = """>>> rng.round('H')
DatetimeIndex(['2018-01-01 12:00:00', '2018-01-01 12:00:00',
'2018-01-01 12:00:00'],
dtype='datetime64[ns]', freq=None)
**Series**
>>> pd.Series(rng).dt.round("H")
0 2018-01-01 12:00:00
1 2018-01-01 12:00:00
2 2018-01-01 12:00:00
dtype: datetime64[ns]
"""
_floor_example = """>>> rng.floor('H')
DatetimeIndex(['2018-01-01 11:00:00', '2018-01-01 12:00:00',
'2018-01-01 12:00:00'],
dtype='datetime64[ns]', freq=None)
**Series**
>>> pd.Series(rng).dt.floor("H")
0 2018-01-01 11:00:00
1 2018-01-01 12:00:00
2 2018-01-01 12:00:00
dtype: datetime64[ns]
"""
_ceil_example = """>>> rng.ceil('H')
DatetimeIndex(['2018-01-01 12:00:00', '2018-01-01 12:00:00',
'2018-01-01 13:00:00'],
dtype='datetime64[ns]', freq=None)
**Series**
>>> pd.Series(rng).dt.ceil("H")
0 2018-01-01 12:00:00
1 2018-01-01 12:00:00
2 2018-01-01 13:00:00
dtype: datetime64[ns]
"""
def _round(self, freq, mode, ambiguous, nonexistent):
# round the local times
values = _ensure_datetimelike_to_i8(self)
result = round_nsint64(values, mode, freq)
result = self._maybe_mask_results(result, fill_value=NaT)
dtype = self.dtype
if is_datetime64tz_dtype(self):
dtype = None
return self._ensure_localized(
self._simple_new(result, dtype=dtype), ambiguous, nonexistent
)
@Appender((_round_doc + _round_example).format(op="round"))
def round(self, freq, ambiguous="raise", nonexistent="raise"):
return self._round(freq, RoundTo.NEAREST_HALF_EVEN, ambiguous, nonexistent)
@Appender((_round_doc + _floor_example).format(op="floor"))
def floor(self, freq, ambiguous="raise", nonexistent="raise"):
return self._round(freq, RoundTo.MINUS_INFTY, ambiguous, nonexistent)
@Appender((_round_doc + _ceil_example).format(op="ceil"))
def ceil(self, freq, ambiguous="raise", nonexistent="raise"):
return self._round(freq, RoundTo.PLUS_INFTY, ambiguous, nonexistent)
class DatetimeLikeArrayMixin(ExtensionOpsMixin, AttributesMixin, ExtensionArray):
"""
Shared Base/Mixin class for DatetimeArray, TimedeltaArray, PeriodArray
Assumes that __new__/__init__ defines:
_data
_freq
and that the inheriting class has methods:
_generate_range
"""
@property
def _box_func(self):
"""
box function to get object from internal representation
"""
raise AbstractMethodError(self)
def _box_values(self, values):
"""
apply box func to passed values
"""
return lib.map_infer(values, self._box_func)
def __iter__(self):
return (self._box_func(v) for v in self.asi8)
@property
def asi8(self) -> np.ndarray:
"""
Integer representation of the values.
Returns
-------
ndarray
An ndarray with int64 dtype.
"""
# do not cache or you'll create a memory leak
return self._data.view("i8")
@property
def _ndarray_values(self):
return self._data
# ----------------------------------------------------------------
# Rendering Methods
def _format_native_types(self, na_rep="NaT", date_format=None):
"""
Helper method for astype when converting to strings.
Returns
-------
ndarray[str]
"""
raise AbstractMethodError(self)
def _formatter(self, boxed=False):
# TODO: Remove Datetime & DatetimeTZ formatters.
return "'{}'".format
# ----------------------------------------------------------------
# Array-Like / EA-Interface Methods
@property
def nbytes(self):
return self._data.nbytes
def __array__(self, dtype=None):
# used for Timedelta/DatetimeArray, overwritten by PeriodArray
if is_object_dtype(dtype):
return np.array(list(self), dtype=object)
return self._data
@property
def size(self) -> int:
"""The number of elements in this array."""
return np.prod(self.shape)
def __len__(self) -> int:
return len(self._data)
def __getitem__(self, key):
"""
This getitem defers to the underlying array, which by-definition can
only handle list-likes, slices, and integer scalars
"""
is_int = lib.is_integer(key)
if lib.is_scalar(key) and not is_int:
raise IndexError(
"only integers, slices (`:`), ellipsis (`...`), "
"numpy.newaxis (`None`) and integer or boolean "
"arrays are valid indices"
)
getitem = self._data.__getitem__
if is_int:
val = getitem(key)
return self._box_func(val)
if com.is_bool_indexer(key):
key = np.asarray(key, dtype=bool)
if key.all():
key = slice(0, None, None)
else:
key = lib.maybe_booleans_to_slice(key.view(np.uint8))
is_period = is_period_dtype(self)
if is_period:
freq = self.freq
else:
freq = None
if isinstance(key, slice):
if self.freq is not None and key.step is not None:
freq = key.step * self.freq
else:
freq = self.freq
elif key is Ellipsis:
# GH#21282 indexing with Ellipsis is similar to a full slice,
# should preserve `freq` attribute
freq = self.freq
result = getitem(key)
if result.ndim > 1:
# To support MPL which performs slicing with 2 dim
# even though it only has 1 dim by definition
if is_period:
return self._simple_new(result, dtype=self.dtype, freq=freq)
return result
return self._simple_new(result, dtype=self.dtype, freq=freq)
def __setitem__(
self,
key: Union[int, Sequence[int], Sequence[bool], slice],
value: Union[NaTType, Any, Sequence[Any]],
) -> None:
# I'm fudging the types a bit here. "Any" above really depends
# on type(self). For PeriodArray, it's Period (or stuff coercible
# to a period in from_sequence). For DatetimeArray, it's Timestamp...
# I don't know if mypy can do that, possibly with Generics.
# https://mypy.readthedocs.io/en/latest/generics.html
if lib.is_scalar(value) and not isna(value):
value = com.maybe_box_datetimelike(value)
if is_list_like(value):
is_slice = isinstance(key, slice)
if lib.is_scalar(key):
raise ValueError("setting an array element with a sequence.")
if not is_slice:
key = cast(Sequence, key)
if len(key) != len(value) and not com.is_bool_indexer(key):
msg = (
"shape mismatch: value array of length '{}' does "
"not match indexing result of length '{}'."
)
raise ValueError(msg.format(len(key), len(value)))
elif not len(key):
return
value = type(self)._from_sequence(value, dtype=self.dtype)
self._check_compatible_with(value)
value = value.asi8
elif isinstance(value, self._scalar_type):
self._check_compatible_with(value)
value = self._unbox_scalar(value)
elif is_valid_nat_for_dtype(value, self.dtype):
value = iNaT
else:
msg = (
"'value' should be a '{scalar}', 'NaT', or array of those. "
"Got '{typ}' instead."
)
raise TypeError(
msg.format(scalar=self._scalar_type.__name__, typ=type(value).__name__)
)
self._data[key] = value
self._maybe_clear_freq()
def _maybe_clear_freq(self):
# inplace operations like __setitem__ may invalidate the freq of
# DatetimeArray and TimedeltaArray
pass
def astype(self, dtype, copy=True):
# Some notes on cases we don't have to handle here in the base class:
# 1. PeriodArray.astype handles period -> period
# 2. DatetimeArray.astype handles conversion between tz.
# 3. DatetimeArray.astype handles datetime -> period
from pandas import Categorical
dtype = pandas_dtype(dtype)
if is_object_dtype(dtype):
return self._box_values(self.asi8)
elif is_string_dtype(dtype) and not is_categorical_dtype(dtype):
return self._format_native_types()
elif is_integer_dtype(dtype):
# we deliberately ignore int32 vs. int64 here.
# See https://github.com/pandas-dev/pandas/issues/24381 for more.
values = self.asi8
if is_unsigned_integer_dtype(dtype):
# Again, we ignore int32 vs. int64
values = values.view("uint64")
if copy:
values = values.copy()
return values
elif (
is_datetime_or_timedelta_dtype(dtype)
and not is_dtype_equal(self.dtype, dtype)
) or is_float_dtype(dtype):
# disallow conversion between datetime/timedelta,
# and conversions for any datetimelike to float
msg = "Cannot cast {name} to dtype {dtype}"
raise TypeError(msg.format(name=type(self).__name__, dtype=dtype))
elif is_categorical_dtype(dtype):
return Categorical(self, dtype=dtype)
else:
return np.asarray(self, dtype=dtype)
def view(self, dtype=None):
if dtype is None or dtype is self.dtype:
return type(self)(self._data, dtype=self.dtype)
return self._data.view(dtype=dtype)
# ------------------------------------------------------------------
# ExtensionArray Interface
def unique(self):
result = unique1d(self.asi8)
return type(self)(result, dtype=self.dtype)
def _validate_fill_value(self, fill_value):
"""
If a fill_value is passed to `take` convert it to an i8 representation,
raising ValueError if this is not possible.
Parameters
----------
fill_value : object
Returns
-------
fill_value : np.int64
Raises
------
ValueError
"""
raise AbstractMethodError(self)
def take(self, indices, allow_fill=False, fill_value=None):
if allow_fill:
fill_value = self._validate_fill_value(fill_value)
new_values = take(
self.asi8, indices, allow_fill=allow_fill, fill_value=fill_value
)
return type(self)(new_values, dtype=self.dtype)
@classmethod
def _concat_same_type(cls, to_concat):
dtypes = {x.dtype for x in to_concat}
assert len(dtypes) == 1
dtype = list(dtypes)[0]
values = np.concatenate([x.asi8 for x in to_concat])
return cls(values, dtype=dtype)
def copy(self):
values = self.asi8.copy()
return type(self)._simple_new(values, dtype=self.dtype, freq=self.freq)
def _values_for_factorize(self):
return self.asi8, iNaT
@classmethod
def _from_factorized(cls, values, original):
return cls(values, dtype=original.dtype)
def _values_for_argsort(self):
return self._data
# ------------------------------------------------------------------
# Additional array methods
# These are not part of the EA API, but we implement them because
# pandas assumes they're there.
def searchsorted(self, value, side="left", sorter=None):
"""
Find indices where elements should be inserted to maintain order.
Find the indices into a sorted array `self` such that, if the
corresponding elements in `value` were inserted before the indices,
the order of `self` would be preserved.
Parameters
----------
value : array_like
Values to insert into `self`.
side : {'left', 'right'}, optional
If 'left', the index of the first suitable location found is given.
If 'right', return the last such index. If there is no suitable
index, return either 0 or N (where N is the length of `self`).
sorter : 1-D array_like, optional
Optional array of integer indices that sort `self` into ascending
order. They are typically the result of ``np.argsort``.
Returns
-------
indices : array of ints
Array of insertion points with the same shape as `value`.
"""
if isinstance(value, str):
value = self._scalar_from_string(value)
if not (isinstance(value, (self._scalar_type, type(self))) or isna(value)):
raise ValueError(
"Unexpected type for 'value': {valtype}".format(valtype=type(value))
)
self._check_compatible_with(value)
if isinstance(value, type(self)):
value = value.asi8
else:
value = self._unbox_scalar(value)
return self.asi8.searchsorted(value, side=side, sorter=sorter)
def repeat(self, repeats, *args, **kwargs):
"""
Repeat elements of an array.
See Also
--------
numpy.ndarray.repeat
"""
nv.validate_repeat(args, kwargs)
values = self._data.repeat(repeats)
return type(self)(values.view("i8"), dtype=self.dtype)
def value_counts(self, dropna=False):
"""
Return a Series containing counts of unique values.
Parameters
----------
dropna : bool, default True
Don't include counts of NaT values.
Returns
-------
Series
"""
from pandas import Series, Index
if dropna:
values = self[~self.isna()]._data
else:
values = self._data
cls = type(self)
result = value_counts(values, sort=False, dropna=dropna)
index = Index(
cls(result.index.view("i8"), dtype=self.dtype), name=result.index.name
)
return Series(result.values, index=index, name=result.name)
def map(self, mapper):
# TODO(GH-23179): Add ExtensionArray.map
# Need to figure out if we want ExtensionArray.map first.
# If so, then we can refactor IndexOpsMixin._map_values to
# a standalone function and call from here..
# Else, just rewrite _map_infer_values to do the right thing.
from pandas import Index
return Index(self).map(mapper).array
# ------------------------------------------------------------------
# Null Handling
def isna(self):
return self._isnan
@property # NB: override with cache_readonly in immutable subclasses
def _isnan(self):
"""
return if each value is nan
"""
return self.asi8 == iNaT
@property # NB: override with cache_readonly in immutable subclasses
def _hasnans(self):
"""
return if I have any nans; enables various perf speedups
"""
return bool(self._isnan.any())
def _maybe_mask_results(self, result, fill_value=iNaT, convert=None):
"""
Parameters
----------
result : a ndarray
fill_value : object, default iNaT
convert : str, dtype or None
Returns
-------
result : ndarray with values replace by the fill_value
mask the result if needed, convert to the provided dtype if its not
None
This is an internal routine.
"""
if self._hasnans:
if convert:
result = result.astype(convert)
if fill_value is None:
fill_value = np.nan
result[self._isnan] = fill_value
return result
def fillna(self, value=None, method=None, limit=None):
# TODO(GH-20300): remove this
# Just overriding to ensure that we avoid an astype(object).
# Either 20300 or a `_values_for_fillna` would avoid this duplication.
if isinstance(value, ABCSeries):
value = value.array
value, method = validate_fillna_kwargs(value, method)
mask = self.isna()
if is_array_like(value):
if len(value) != len(self):
raise ValueError(
"Length of 'value' does not match. Got ({}) "
" expected {}".format(len(value), len(self))
)
value = value[mask]
if mask.any():
if method is not None:
if method == "pad":
func = missing.pad_1d
else:
func = missing.backfill_1d
values = self._data
if not is_period_dtype(self):
# For PeriodArray self._data is i8, which gets copied
# by `func`. Otherwise we need to make a copy manually
# to avoid modifying `self` in-place.
values = values.copy()
new_values = func(values, limit=limit, mask=mask)
if is_datetime64tz_dtype(self):
# we need to pass int64 values to the constructor to avoid
# re-localizing incorrectly
new_values = new_values.view("i8")
new_values = type(self)(new_values, dtype=self.dtype)
else:
# fill with value
new_values = self.copy()
new_values[mask] = value
else:
new_values = self.copy()
return new_values
# ------------------------------------------------------------------
# Frequency Properties/Methods
@property
def freq(self):
"""
Return the frequency object if it is set, otherwise None.
"""
return self._freq
@freq.setter
def freq(self, value):
if value is not None:
value = frequencies.to_offset(value)
self._validate_frequency(self, value)
self._freq = value
@property
def freqstr(self):
"""
Return the frequency object as a string if its set, otherwise None
"""
if self.freq is None:
return None
return self.freq.freqstr
@property # NB: override with cache_readonly in immutable subclasses
def inferred_freq(self):
"""
Tryies to return a string representing a frequency guess,
generated by infer_freq. Returns None if it can't autodetect the
frequency.
"""
try:
return frequencies.infer_freq(self)
except ValueError:
return None
@property # NB: override with cache_readonly in immutable subclasses
def _resolution(self):
return frequencies.Resolution.get_reso_from_freq(self.freqstr)
@property # NB: override with cache_readonly in immutable subclasses
def resolution(self):
"""
Returns day, hour, minute, second, millisecond or microsecond
"""
return frequencies.Resolution.get_str(self._resolution)
@classmethod
def _validate_frequency(cls, index, freq, **kwargs):
"""
Validate that a frequency is compatible with the values of a given
Datetime Array/Index or Timedelta Array/Index
Parameters
----------
index : DatetimeIndex or TimedeltaIndex
The index on which to determine if the given frequency is valid
freq : DateOffset
The frequency to validate
"""
if is_period_dtype(cls):
# Frequency validation is not meaningful for Period Array/Index
return None
inferred = index.inferred_freq
if index.size == 0 or inferred == freq.freqstr:
return None
try:
on_freq = cls._generate_range(
start=index[0], end=None, periods=len(index), freq=freq, **kwargs
)
if not np.array_equal(index.asi8, on_freq.asi8):
raise ValueError
except ValueError as e:
if "non-fixed" in str(e):
# non-fixed frequencies are not meaningful for timedelta64;
# we retain that error message
raise e
# GH#11587 the main way this is reached is if the `np.array_equal`
# check above is False. This can also be reached if index[0]
# is `NaT`, in which case the call to `cls._generate_range` will
# raise a ValueError, which we re-raise with a more targeted
# message.
raise ValueError(
"Inferred frequency {infer} from passed values "
"does not conform to passed frequency {passed}".format(
infer=inferred, passed=freq.freqstr
)
)
# monotonicity/uniqueness properties are called via frequencies.infer_freq,
# see GH#23789
@property
def _is_monotonic_increasing(self):
return algos.is_monotonic(self.asi8, timelike=True)[0]
@property
def _is_monotonic_decreasing(self):
return algos.is_monotonic(self.asi8, timelike=True)[1]
@property
def _is_unique(self):
return len(unique1d(self.asi8)) == len(self)
# ------------------------------------------------------------------
# Arithmetic Methods
# pow is invalid for all three subclasses; TimedeltaArray will override
# the multiplication and division ops
__pow__ = make_invalid_op("__pow__")
__rpow__ = make_invalid_op("__rpow__")
__mul__ = make_invalid_op("__mul__")
__rmul__ = make_invalid_op("__rmul__")
__truediv__ = make_invalid_op("__truediv__")
__rtruediv__ = make_invalid_op("__rtruediv__")
__floordiv__ = make_invalid_op("__floordiv__")
__rfloordiv__ = make_invalid_op("__rfloordiv__")
__mod__ = make_invalid_op("__mod__")
__rmod__ = make_invalid_op("__rmod__")
__divmod__ = make_invalid_op("__divmod__")
__rdivmod__ = make_invalid_op("__rdivmod__")
def _add_datetimelike_scalar(self, other):
# Overriden by TimedeltaArray
raise TypeError(
"cannot add {cls} and {typ}".format(
cls=type(self).__name__, typ=type(other).__name__
)
)
_add_datetime_arraylike = _add_datetimelike_scalar
def _sub_datetimelike_scalar(self, other):
# Overridden by DatetimeArray
assert other is not NaT
raise TypeError(
"cannot subtract a datelike from a {cls}".format(cls=type(self).__name__)
)
_sub_datetime_arraylike = _sub_datetimelike_scalar
def _sub_period(self, other):
# Overriden by PeriodArray
raise TypeError(
"cannot subtract Period from a {cls}".format(cls=type(self).__name__)
)
def _add_offset(self, offset):
raise AbstractMethodError(self)
def _add_delta(self, other):
"""
Add a timedelta-like, Tick or TimedeltaIndex-like object
to self, yielding an int64 numpy array
Parameters
----------
delta : {timedelta, np.timedelta64, Tick,
TimedeltaIndex, ndarray[timedelta64]}
Returns
-------
result : ndarray[int64]
Notes
-----
The result's name is set outside of _add_delta by the calling
method (__add__ or __sub__), if necessary (i.e. for Indexes).
"""
if isinstance(other, (Tick, timedelta, np.timedelta64)):
new_values = self._add_timedeltalike_scalar(other)
elif is_timedelta64_dtype(other):
# ndarray[timedelta64] or TimedeltaArray/index
new_values = self._add_delta_tdi(other)
return new_values
def _add_timedeltalike_scalar(self, other):
"""
Add a delta of a timedeltalike
return the i8 result view
"""
if isna(other):
# i.e np.timedelta64("NaT"), not recognized by delta_to_nanoseconds
new_values = np.empty(len(self), dtype="i8")
new_values[:] = iNaT
return new_values
inc = delta_to_nanoseconds(other)
new_values = checked_add_with_arr(self.asi8, inc, arr_mask=self._isnan).view(
"i8"
)
new_values = self._maybe_mask_results(new_values)
return new_values.view("i8")
def _add_delta_tdi(self, other):
"""
Add a delta of a TimedeltaIndex
return the i8 result view
"""
if len(self) != len(other):
raise ValueError("cannot add indices of unequal length")
if isinstance(other, np.ndarray):
# ndarray[timedelta64]; wrap in TimedeltaIndex for op
from pandas.core.arrays import TimedeltaArray
other = TimedeltaArray._from_sequence(other)
self_i8 = self.asi8
other_i8 = other.asi8
new_values = checked_add_with_arr(
self_i8, other_i8, arr_mask=self._isnan, b_mask=other._isnan
)
if self._hasnans or other._hasnans:
mask = (self._isnan) | (other._isnan)
new_values[mask] = iNaT
return new_values.view("i8")
def _add_nat(self):
"""
Add pd.NaT to self
"""
if is_period_dtype(self):
raise TypeError(
"Cannot add {cls} and {typ}".format(
cls=type(self).__name__, typ=type(NaT).__name__
)
)
# GH#19124 pd.NaT is treated like a timedelta for both timedelta
# and datetime dtypes
result = np.zeros(len(self), dtype=np.int64)
result.fill(iNaT)
return type(self)(result, dtype=self.dtype, freq=None)
def _sub_nat(self):
"""
Subtract pd.NaT from self
"""
# GH#19124 Timedelta - datetime is not in general well-defined.
# We make an exception for pd.NaT, which in this case quacks
# like a timedelta.
# For datetime64 dtypes by convention we treat NaT as a datetime, so
# this subtraction returns a timedelta64 dtype.
# For period dtype, timedelta64 is a close-enough return dtype.
result = np.zeros(len(self), dtype=np.int64)
result.fill(iNaT)
return result.view("timedelta64[ns]")
def _sub_period_array(self, other):
"""
Subtract a Period Array/Index from self. This is only valid if self
is itself a Period Array/Index, raises otherwise. Both objects must
have the same frequency.
Parameters
----------
other : PeriodIndex or PeriodArray
Returns
-------
result : np.ndarray[object]
Array of DateOffset objects; nulls represented by NaT.
"""
if not is_period_dtype(self):
raise TypeError(
"cannot subtract {dtype}-dtype from {cls}".format(
dtype=other.dtype, cls=type(self).__name__
)
)
if len(self) != len(other):
raise ValueError("cannot subtract arrays/indices of unequal length")
if self.freq != other.freq:
msg = DIFFERENT_FREQ.format(
cls=type(self).__name__, own_freq=self.freqstr, other_freq=other.freqstr
)
raise IncompatibleFrequency(msg)
new_values = checked_add_with_arr(
self.asi8, -other.asi8, arr_mask=self._isnan, b_mask=other._isnan
)
new_values = np.array([self.freq.base * x for x in new_values])
if self._hasnans or other._hasnans:
mask = (self._isnan) | (other._isnan)
new_values[mask] = NaT
return new_values
def _addsub_int_array(self, other, op):
"""
Add or subtract array-like of integers equivalent to applying
`_time_shift` pointwise.
Parameters
----------
other : Index, ExtensionArray, np.ndarray
integer-dtype
op : {operator.add, operator.sub}
Returns
-------
result : same class as self
"""
# _addsub_int_array is overriden by PeriodArray
assert not is_period_dtype(self)
assert op in [operator.add, operator.sub]
if self.freq is None:
# GH#19123
raise NullFrequencyError("Cannot shift with no freq")
elif isinstance(self.freq, Tick):
# easy case where we can convert to timedelta64 operation
td = Timedelta(self.freq)
return op(self, td * other)
# We should only get here with DatetimeIndex; dispatch
# to _addsub_offset_array
assert not is_timedelta64_dtype(self)
return op(self, np.array(other) * self.freq)
def _addsub_offset_array(self, other, op):
"""
Add or subtract array-like of DateOffset objects
Parameters
----------
other : Index, np.ndarray
object-dtype containing pd.DateOffset objects
op : {operator.add, operator.sub}
Returns
-------
result : same class as self
"""
assert op in [operator.add, operator.sub]
if len(other) == 1:
return op(self, other[0])
warnings.warn(
"Adding/subtracting array of DateOffsets to "
"{cls} not vectorized".format(cls=type(self).__name__),
PerformanceWarning,
)
# For EA self.astype('O') returns a numpy array, not an Index
left = self.astype("O")
res_values = op(left, np.array(other))
kwargs = {}
if not is_period_dtype(self):
kwargs["freq"] = "infer"
return self._from_sequence(res_values, **kwargs)
def _time_shift(self, periods, freq=None):
"""
Shift each value by `periods`.
Note this is different from ExtensionArray.shift, which
shifts the *position* of each element, padding the end with
missing values.
Parameters
----------
periods : int
Number of periods to shift by.
freq : pandas.DateOffset, pandas.Timedelta, or str
Frequency increment to shift by.
"""
if freq is not None and freq != self.freq:
if isinstance(freq, str):
freq = frequencies.to_offset(freq)
offset = periods * freq
result = self + offset
return result
if periods == 0:
# immutable so OK
return self.copy()
if self.freq is None:
raise NullFrequencyError("Cannot shift with no freq")
start = self[0] + periods * self.freq
end = self[-1] + periods * self.freq
# Note: in the DatetimeTZ case, _generate_range will infer the
# appropriate timezone from `start` and `end`, so tz does not need
# to be passed explicitly.
return self._generate_range(start=start, end=end, periods=None, freq=self.freq)
def __add__(self, other):
other = lib.item_from_zerodim(other)
if isinstance(other, (ABCSeries, ABCDataFrame, ABCIndexClass)):
return NotImplemented
# scalar others
elif other is NaT:
result = self._add_nat()
elif isinstance(other, (Tick, timedelta, np.timedelta64)):
result = self._add_delta(other)
elif isinstance(other, DateOffset):
# specifically _not_ a Tick
result = self._add_offset(other)
elif isinstance(other, (datetime, np.datetime64)):
result = self._add_datetimelike_scalar(other)
elif lib.is_integer(other):
# This check must come after the check for np.timedelta64
# as is_integer returns True for these
if not is_period_dtype(self):
maybe_integer_op_deprecated(self)
result = self._time_shift(other)
# array-like others
elif is_timedelta64_dtype(other):
# TimedeltaIndex, ndarray[timedelta64]
result = self._add_delta(other)
elif is_offsetlike(other):
# Array/Index of DateOffset objects
result = self._addsub_offset_array(other, operator.add)
elif is_datetime64_dtype(other) or is_datetime64tz_dtype(other):
# DatetimeIndex, ndarray[datetime64]
return self._add_datetime_arraylike(other)
elif is_integer_dtype(other):
if not is_period_dtype(self):
maybe_integer_op_deprecated(self)
result = self._addsub_int_array(other, operator.add)
else:
# Includes Categorical, other ExtensionArrays
# For PeriodDtype, if self is a TimedeltaArray and other is a
# PeriodArray with a timedelta-like (i.e. Tick) freq, this
# operation is valid. Defer to the PeriodArray implementation.
# In remaining cases, this will end up raising TypeError.
return NotImplemented
if is_timedelta64_dtype(result) and isinstance(result, np.ndarray):
from pandas.core.arrays import TimedeltaArray
return TimedeltaArray(result)
return result
def __radd__(self, other):
# alias for __add__
return self.__add__(other)
def __sub__(self, other):
other = lib.item_from_zerodim(other)
if isinstance(other, (ABCSeries, ABCDataFrame, ABCIndexClass)):
return NotImplemented
# scalar others
elif other is NaT:
result = self._sub_nat()
elif isinstance(other, (Tick, timedelta, np.timedelta64)):
result = self._add_delta(-other)
elif isinstance(other, DateOffset):
# specifically _not_ a Tick
result = self._add_offset(-other)
elif isinstance(other, (datetime, np.datetime64)):
result = self._sub_datetimelike_scalar(other)
elif lib.is_integer(other):
# This check must come after the check for np.timedelta64
# as is_integer returns True for these
if not is_period_dtype(self):
maybe_integer_op_deprecated(self)
result = self._time_shift(-other)
elif isinstance(other, Period):
result = self._sub_period(other)
# array-like others
elif is_timedelta64_dtype(other):
# TimedeltaIndex, ndarray[timedelta64]
result = self._add_delta(-other)
elif is_offsetlike(other):
# Array/Index of DateOffset objects
result = self._addsub_offset_array(other, operator.sub)
elif is_datetime64_dtype(other) or is_datetime64tz_dtype(other):
# DatetimeIndex, ndarray[datetime64]
result = self._sub_datetime_arraylike(other)
elif is_period_dtype(other):
# PeriodIndex
result = self._sub_period_array(other)
elif is_integer_dtype(other):
if not is_period_dtype(self):
maybe_integer_op_deprecated(self)
result = self._addsub_int_array(other, operator.sub)
else:
# Includes ExtensionArrays, float_dtype
return NotImplemented
if is_timedelta64_dtype(result) and isinstance(result, np.ndarray):
from pandas.core.arrays import TimedeltaArray
return TimedeltaArray(result)
return result
def __rsub__(self, other):
if is_datetime64_any_dtype(other) and is_timedelta64_dtype(self.dtype):
# ndarray[datetime64] cannot be subtracted from self, so
# we need to wrap in DatetimeArray/Index and flip the operation
if not isinstance(other, DatetimeLikeArrayMixin):
# Avoid down-casting DatetimeIndex
from pandas.core.arrays import DatetimeArray
other = DatetimeArray(other)
return other - self
elif (
is_datetime64_any_dtype(self.dtype)
and hasattr(other, "dtype")
and not is_datetime64_any_dtype(other.dtype)
):
# GH#19959 datetime - datetime is well-defined as timedelta,
# but any other type - datetime is not well-defined.
raise TypeError(
"cannot subtract {cls} from {typ}".format(
cls=type(self).__name__, typ=type(other).__name__
)
)
elif is_period_dtype(self.dtype) and is_timedelta64_dtype(other):
# TODO: Can we simplify/generalize these cases at all?
raise TypeError(
"cannot subtract {cls} from {dtype}".format(
cls=type(self).__name__, dtype=other.dtype
)
)
elif is_timedelta64_dtype(self.dtype):
if lib.is_integer(other) or is_integer_dtype(other):
# need to subtract before negating, since that flips freq
# -self flips self.freq, messing up results
return -(self - other)
return (-self) + other
return -(self - other)
# FIXME: DTA/TDA/PA inplace methods should actually be inplace, GH#24115
def __iadd__(self, other):
# alias for __add__
return self.__add__(other)
def __isub__(self, other):
# alias for __sub__
return self.__sub__(other)
# --------------------------------------------------------------
# Comparison Methods
def _ensure_localized(
self, arg, ambiguous="raise", nonexistent="raise", from_utc=False
):
"""
Ensure that we are re-localized.
This is for compat as we can then call this on all datetimelike
arrays generally (ignored for Period/Timedelta)
Parameters
----------
arg : Union[DatetimeLikeArray, DatetimeIndexOpsMixin, ndarray]
ambiguous : str, bool, or bool-ndarray, default 'raise'
nonexistent : str, default 'raise'
from_utc : bool, default False
If True, localize the i8 ndarray to UTC first before converting to
the appropriate tz. If False, localize directly to the tz.
Returns
-------
localized array
"""
# reconvert to local tz
tz = getattr(self, "tz", None)
if tz is not None:
if not isinstance(arg, type(self)):
arg = self._simple_new(arg)
if from_utc:
arg = arg.tz_localize("UTC").tz_convert(self.tz)
else:
arg = arg.tz_localize(
self.tz, ambiguous=ambiguous, nonexistent=nonexistent
)
return arg
# --------------------------------------------------------------
# Reductions
def _reduce(self, name, axis=0, skipna=True, **kwargs):
op = getattr(self, name, None)
if op:
return op(skipna=skipna, **kwargs)
else:
return super()._reduce(name, skipna, **kwargs)
def min(self, axis=None, skipna=True, *args, **kwargs):
"""
Return the minimum value of the Array or minimum along
an axis.
See Also
--------
numpy.ndarray.min
Index.min : Return the minimum value in an Index.
Series.min : Return the minimum value in a Series.
"""
nv.validate_min(args, kwargs)
nv.validate_minmax_axis(axis)
result = nanops.nanmin(self.asi8, skipna=skipna, mask=self.isna())
if isna(result):
# Period._from_ordinal does not handle np.nan gracefully
return NaT
return self._box_func(result)
def max(self, axis=None, skipna=True, *args, **kwargs):
"""
Return the maximum value of the Array or maximum along
an axis.
See Also
--------
numpy.ndarray.max
Index.max : Return the maximum value in an Index.
Series.max : Return the maximum value in a Series.
"""
# TODO: skipna is broken with max.
# See https://github.com/pandas-dev/pandas/issues/24265
nv.validate_max(args, kwargs)
nv.validate_minmax_axis(axis)
mask = self.isna()
if skipna:
values = self[~mask].asi8
elif mask.any():
return NaT
else:
values = self.asi8
if not len(values):
# short-circuit for empty max / min
return NaT
result = nanops.nanmax(values, skipna=skipna)
# Don't have to worry about NA `result`, since no NA went in.
return self._box_func(result)
def mean(self, skipna=True):
"""
Return the mean value of the Array.
.. versionadded:: 0.25.0
Parameters
----------
skipna : bool, default True
Whether to ignore any NaT elements.
Returns
-------
scalar
Timestamp or Timedelta.
See Also
--------
numpy.ndarray.mean : Returns the average of array elements along a given axis.
Series.mean : Return the mean value in a Series.
Notes
-----
mean is only defined for Datetime and Timedelta dtypes, not for Period.
"""
if is_period_dtype(self):
# See discussion in GH#24757
raise TypeError(
"mean is not implemented for {cls} since the meaning is "
"ambiguous. An alternative is "
"obj.to_timestamp(how='start').mean()".format(cls=type(self).__name__)
)
mask = self.isna()
if skipna:
values = self[~mask]
elif mask.any():
return NaT
else:
values = self
if not len(values):
# short-circut for empty max / min
return NaT
result = nanops.nanmean(values.view("i8"), skipna=skipna)
# Don't have to worry about NA `result`, since no NA went in.
return self._box_func(result)
# -------------------------------------------------------------------
# Shared Constructor Helpers
def validate_periods(periods):
"""
If a `periods` argument is passed to the Datetime/Timedelta Array/Index
constructor, cast it to an integer.
Parameters
----------
periods : None, float, int
Returns
-------
periods : None or int
Raises
------
TypeError
if periods is None, float, or int
"""
if periods is not None:
if lib.is_float(periods):
periods = int(periods)
elif not lib.is_integer(periods):
raise TypeError(
"periods must be a number, got {periods}".format(periods=periods)
)
return periods
def validate_endpoints(closed):
"""
Check that the `closed` argument is among [None, "left", "right"]
Parameters
----------
closed : {None, "left", "right"}
Returns
-------
left_closed : bool
right_closed : bool
Raises
------
ValueError : if argument is not among valid values
"""
left_closed = False
right_closed = False
if closed is None:
left_closed = True
right_closed = True
elif closed == "left":
left_closed = True
elif closed == "right":
right_closed = True
else:
raise ValueError("Closed has to be either 'left', 'right' or None")
return left_closed, right_closed
def validate_inferred_freq(freq, inferred_freq, freq_infer):
"""
If the user passes a freq and another freq is inferred from passed data,
require that they match.
Parameters
----------
freq : DateOffset or None
inferred_freq : DateOffset or None
freq_infer : bool
Returns
-------
freq : DateOffset or None
freq_infer : bool
Notes
-----
We assume at this point that `maybe_infer_freq` has been called, so
`freq` is either a DateOffset object or None.
"""
if inferred_freq is not None:
if freq is not None and freq != inferred_freq:
raise ValueError(
"Inferred frequency {inferred} from passed "
"values does not conform to passed frequency "
"{passed}".format(inferred=inferred_freq, passed=freq.freqstr)
)
elif freq is None:
freq = inferred_freq
freq_infer = False
return freq, freq_infer
def maybe_infer_freq(freq):
"""
Comparing a DateOffset to the string "infer" raises, so we need to
be careful about comparisons. Make a dummy variable `freq_infer` to
signify the case where the given freq is "infer" and set freq to None
to avoid comparison trouble later on.
Parameters
----------
freq : {DateOffset, None, str}
Returns
-------
freq : {DateOffset, None}
freq_infer : bool
"""
freq_infer = False
if not isinstance(freq, DateOffset):
# if a passed freq is None, don't infer automatically
if freq != "infer":
freq = frequencies.to_offset(freq)
else:
freq_infer = True
freq = None
return freq, freq_infer
def _ensure_datetimelike_to_i8(other, to_utc=False):
"""
Helper for coercing an input scalar or array to i8.
Parameters
----------
other : 1d array
to_utc : bool, default False
If True, convert the values to UTC before extracting the i8 values
If False, extract the i8 values directly.
Returns
-------
i8 1d array
"""
from pandas import Index
if lib.is_scalar(other) and isna(other):
return iNaT
elif isinstance(other, (ABCPeriodArray, ABCIndexClass, DatetimeLikeArrayMixin)):
# convert tz if needed
if getattr(other, "tz", None) is not None:
if to_utc:
other = other.tz_convert("UTC")
else:
other = other.tz_localize(None)
else:
try:
return np.array(other, copy=False).view("i8")
except TypeError:
# period array cannot be coerced to int
other = Index(other)
return other.asi8
from datetime import datetime, timedelta
import operator
from typing import Any, Sequence, Type, Union, cast
import warnings
import numpy as np
from pandas._libs import NaT, NaTType, Timestamp, algos, iNaT, lib
from pandas._libs.tslibs.c_timestamp import maybe_integer_op_deprecated
from pandas._libs.tslibs.period import DIFFERENT_FREQ, IncompatibleFrequency, Period
from pandas._libs.tslibs.timedeltas import Timedelta, delta_to_nanoseconds
from pandas._libs.tslibs.timestamps import RoundTo, round_nsint64
from pandas.compat.numpy import function as nv
from pandas.errors import AbstractMethodError, NullFrequencyError, PerformanceWarning
from pandas.util._decorators import Appender, Substitution
from pandas.util._validators import validate_fillna_kwargs
from pandas.core.dtypes.common import (
is_categorical_dtype,
is_datetime64_any_dtype,
is_datetime64_dtype,
is_datetime64tz_dtype,
is_datetime_or_timedelta_dtype,
is_dtype_equal,
is_float_dtype,
is_integer_dtype,
is_list_like,
is_object_dtype,
is_offsetlike,
is_period_dtype,
is_string_dtype,
is_timedelta64_dtype,
is_unsigned_integer_dtype,
pandas_dtype,
)
from pandas.core.dtypes.generic import (
ABCDataFrame,
ABCIndexClass,
ABCPeriodArray,
ABCSeries,
)
from pandas.core.dtypes.inference import is_array_like
from pandas.core.dtypes.missing import is_valid_nat_for_dtype, isna
from pandas._typing import DatetimeLikeScalar
from pandas.core import missing, nanops
from pandas.core.algorithms import checked_add_with_arr, take, unique1d, value_counts
import pandas.core.common as com
from pandas.core.ops.invalid import make_invalid_op
from pandas.tseries import frequencies
from pandas.tseries.offsets import DateOffset, Tick
from .base import ExtensionArray, ExtensionOpsMixin
class AttributesMixin:
_data = None # type: np.ndarray
@classmethod
def _simple_new(cls, values, **kwargs):
raise AbstractMethodError(cls)
@property
def _scalar_type(self) -> Type[DatetimeLikeScalar]:
"""The scalar associated with this datelike
* PeriodArray : Period
* DatetimeArray : Timestamp
* TimedeltaArray : Timedelta
"""
raise AbstractMethodError(self)
def _scalar_from_string(
self, value: str
) -> Union[Period, Timestamp, Timedelta, NaTType]:
"""
Construct a scalar type from a string.
Parameters
----------
value : str
Returns
-------
Period, Timestamp, or Timedelta, or NaT
Whatever the type of ``self._scalar_type`` is.
Notes
-----
This should call ``self._check_compatible_with`` before
unboxing the result.
"""
raise AbstractMethodError(self)
def _unbox_scalar(self, value: Union[Period, Timestamp, Timedelta, NaTType]) -> int:
"""
Unbox the integer value of a scalar `value`.
Parameters
----------
value : Union[Period, Timestamp, Timedelta]
Returns
-------
int
Examples
--------
>>> self._unbox_scalar(Timedelta('10s')) # DOCTEST: +SKIP
10000000000
"""
raise AbstractMethodError(self)
def _check_compatible_with(
self, other: Union[Period, Timestamp, Timedelta, NaTType]
) -> None:
"""
Verify that `self` and `other` are compatible.
* DatetimeArray verifies that the timezones (if any) match
* PeriodArray verifies that the freq matches
* Timedelta has no verification
In each case, NaT is considered compatible.
Parameters
----------
other
Raises
------
Exception
"""
raise AbstractMethodError(self)
class DatelikeOps:
"""
Common ops for DatetimeIndex/PeriodIndex, but not TimedeltaIndex.
"""
@Substitution(
URL="https://docs.python.org/3/library/datetime.html"
"#strftime-and-strptime-behavior"
)
def strftime(self, date_format):
"""
Convert to Index using specified date_format.
Return an Index of formatted strings specified by date_format, which
supports the same string format as the python standard library. Details
of the string format can be found in `python string format
doc <%(URL)s>`__.
Parameters
----------
date_format : str
Date format string (e.g. "%%Y-%%m-%%d").
Returns
-------
ndarray
NumPy ndarray of formatted strings.
See Also
--------
to_datetime : Convert the given argument to datetime.
DatetimeIndex.normalize : Return DatetimeIndex with times to midnight.
DatetimeIndex.round : Round the DatetimeIndex to the specified freq.
DatetimeIndex.floor : Floor the DatetimeIndex to the specified freq.
Examples
--------
>>> rng = pd.date_range(pd.Timestamp("2018-03-10 09:00"),
... periods=3, freq='s')
>>> rng.strftime('%%B %%d, %%Y, %%r')
Index(['March 10, 2018, 09:00:00 AM', 'March 10, 2018, 09:00:01 AM',
'March 10, 2018, 09:00:02 AM'],
dtype='object')
"""
return self._format_native_types(date_format=date_format).astype(object)
class TimelikeOps:
"""
Common ops for TimedeltaIndex/DatetimeIndex, but not PeriodIndex.
"""
_round_doc = """
Perform {op} operation on the data to the specified `freq`.
Parameters
----------
freq : str or Offset
The frequency level to {op} the index to. Must be a fixed
frequency like 'S' (second) not 'ME' (month end). See
:ref:`frequency aliases <timeseries.offset_aliases>` for
a list of possible `freq` values.
ambiguous : 'infer', bool-ndarray, 'NaT', default 'raise'
Only relevant for DatetimeIndex:
- 'infer' will attempt to infer fall dst-transition hours based on
order
- bool-ndarray where True signifies a DST time, False designates
a non-DST time (note that this flag is only applicable for
ambiguous times)
- 'NaT' will return NaT where there are ambiguous times
- 'raise' will raise an AmbiguousTimeError if there are ambiguous
times.
.. versionadded:: 0.24.0
nonexistent : 'shift_forward', 'shift_backward', 'NaT', timedelta, \
default 'raise'
A nonexistent time does not exist in a particular timezone
where clocks moved forward due to DST.
- 'shift_forward' will shift the nonexistent time forward to the
closest existing time
- 'shift_backward' will shift the nonexistent time backward to the
closest existing time
- 'NaT' will return NaT where there are nonexistent times
- timedelta objects will shift nonexistent times by the timedelta
- 'raise' will raise an NonExistentTimeError if there are
nonexistent times.
.. versionadded:: 0.24.0
Returns
-------
DatetimeIndex, TimedeltaIndex, or Series
Index of the same type for a DatetimeIndex or TimedeltaIndex,
or a Series with the same index for a Series.
Raises
------
ValueError if the `freq` cannot be converted.
Examples
--------
**DatetimeIndex**
>>> rng = pd.date_range('1/1/2018 11:59:00', periods=3, freq='min')
>>> rng
DatetimeIndex(['2018-01-01 11:59:00', '2018-01-01 12:00:00',
'2018-01-01 12:01:00'],
dtype='datetime64[ns]', freq='T')
"""
_round_example = """>>> rng.round('H')
DatetimeIndex(['2018-01-01 12:00:00', '2018-01-01 12:00:00',
'2018-01-01 12:00:00'],
dtype='datetime64[ns]', freq=None)
**Series**
>>> pd.Series(rng).dt.round("H")
0 2018-01-01 12:00:00
1 2018-01-01 12:00:00
2 2018-01-01 12:00:00
dtype: datetime64[ns]
"""
_floor_example = """>>> rng.floor('H')
DatetimeIndex(['2018-01-01 11:00:00', '2018-01-01 12:00:00',
'2018-01-01 12:00:00'],
dtype='datetime64[ns]', freq=None)
**Series**
>>> pd.Series(rng).dt.floor("H")
0 2018-01-01 11:00:00
1 2018-01-01 12:00:00
2 2018-01-01 12:00:00
dtype: datetime64[ns]
"""
_ceil_example = """>>> rng.ceil('H')
DatetimeIndex(['2018-01-01 12:00:00', '2018-01-01 12:00:00',
'2018-01-01 13:00:00'],
dtype='datetime64[ns]', freq=None)
**Series**
>>> pd.Series(rng).dt.ceil("H")
0 2018-01-01 12:00:00
1 2018-01-01 12:00:00
2 2018-01-01 13:00:00
dtype: datetime64[ns]
"""
def _round(self, freq, mode, ambiguous, nonexistent):
# round the local times
values = _ensure_datetimelike_to_i8(self)
result = round_nsint64(values, mode, freq)
result = self._maybe_mask_results(result, fill_value=NaT)
dtype = self.dtype
if is_datetime64tz_dtype(self):
dtype = None
return self._ensure_localized(
self._simple_new(result, dtype=dtype), ambiguous, nonexistent
)
@Appender((_round_doc + _round_example).format(op="round"))
def round(self, freq, ambiguous="raise", nonexistent="raise"):
return self._round(freq, RoundTo.NEAREST_HALF_EVEN, ambiguous, nonexistent)
@Appender((_round_doc + _floor_example).format(op="floor"))
def floor(self, freq, ambiguous="raise", nonexistent="raise"):
return self._round(freq, RoundTo.MINUS_INFTY, ambiguous, nonexistent)
@Appender((_round_doc + _ceil_example).format(op="ceil"))
def ceil(self, freq, ambiguous="raise", nonexistent="raise"):
return self._round(freq, RoundTo.PLUS_INFTY, ambiguous, nonexistent)
class DatetimeLikeArrayMixin(ExtensionOpsMixin, AttributesMixin, ExtensionArray):
"""
Shared Base/Mixin class for DatetimeArray, TimedeltaArray, PeriodArray
Assumes that __new__/__init__ defines:
_data
_freq
and that the inheriting class has methods:
_generate_range
"""
@property
def _box_func(self):
"""
box function to get object from internal representation
"""
raise AbstractMethodError(self)
def _box_values(self, values):
"""
apply box func to passed values
"""
return lib.map_infer(values, self._box_func)
def __iter__(self):
return (self._box_func(v) for v in self.asi8)
@property
def asi8(self) -> np.ndarray:
"""
Integer representation of the values.
Returns
-------
ndarray
An ndarray with int64 dtype.
"""
# do not cache or you'll create a memory leak
return self._data.view("i8")
@property
def _ndarray_values(self):
return self._data
# ----------------------------------------------------------------
# Rendering Methods
def _format_native_types(self, na_rep="NaT", date_format=None):
"""
Helper method for astype when converting to strings.
Returns
-------
ndarray[str]
"""
raise AbstractMethodError(self)
def _formatter(self, boxed=False):
# TODO: Remove Datetime & DatetimeTZ formatters.
return "'{}'".format
# ----------------------------------------------------------------
# Array-Like / EA-Interface Methods
@property
def nbytes(self):
return self._data.nbytes
def __array__(self, dtype=None):
# used for Timedelta/DatetimeArray, overwritten by PeriodArray
if is_object_dtype(dtype):
return np.array(list(self), dtype=object)
return self._data
@property
def size(self) -> int:
"""The number of elements in this array."""
return np.prod(self.shape)
def __len__(self) -> int:
return len(self._data)
def __getitem__(self, key):
"""
This getitem defers to the underlying array, which by-definition can
only handle list-likes, slices, and integer scalars
"""
is_int = lib.is_integer(key)
if lib.is_scalar(key) and not is_int:
raise IndexError(
"only integers, slices (`:`), ellipsis (`...`), "
"numpy.newaxis (`None`) and integer or boolean "
"arrays are valid indices"
)
getitem = self._data.__getitem__
if is_int:
val = getitem(key)
return self._box_func(val)
if com.is_bool_indexer(key):
key = np.asarray(key, dtype=bool)
if key.all():
key = slice(0, None, None)
else:
key = lib.maybe_booleans_to_slice(key.view(np.uint8))
is_period = is_period_dtype(self)
if is_period:
freq = self.freq
else:
freq = None
if isinstance(key, slice):
if self.freq is not None and key.step is not None:
freq = key.step * self.freq
else:
freq = self.freq
elif key is Ellipsis:
# GH#21282 indexing with Ellipsis is similar to a full slice,
# should preserve `freq` attribute
freq = self.freq
result = getitem(key)
if result.ndim > 1:
# To support MPL which performs slicing with 2 dim
# even though it only has 1 dim by definition
if is_period:
return self._simple_new(result, dtype=self.dtype, freq=freq)
return result
return self._simple_new(result, dtype=self.dtype, freq=freq)
def __setitem__(
self,
key: Union[int, Sequence[int], Sequence[bool], slice],
value: Union[NaTType, Any, Sequence[Any]],
) -> None:
# I'm fudging the types a bit here. "Any" above really depends
# on type(self). For PeriodArray, it's Period (or stuff coercible
# to a period in from_sequence). For DatetimeArray, it's Timestamp...
# I don't know if mypy can do that, possibly with Generics.
# https://mypy.readthedocs.io/en/latest/generics.html
if lib.is_scalar(value) and not isna(value):
value = com.maybe_box_datetimelike(value)
if is_list_like(value):
is_slice = isinstance(key, slice)
if lib.is_scalar(key):
raise ValueError("setting an array element with a sequence.")
if not is_slice:
key = cast(Sequence, key)
if len(key) != len(value) and not com.is_bool_indexer(key):
msg = (
"shape mismatch: value array of length '{}' does "
"not match indexing result of length '{}'."
)
raise ValueError(msg.format(len(key), len(value)))
elif not len(key):
return
value = type(self)._from_sequence(value, dtype=self.dtype)
self._check_compatible_with(value)
value = value.asi8
elif isinstance(value, self._scalar_type):
self._check_compatible_with(value)
value = self._unbox_scalar(value)
elif is_valid_nat_for_dtype(value, self.dtype):
value = iNaT
else:
msg = (
"'value' should be a '{scalar}', 'NaT', or array of those. "
"Got '{typ}' instead."
)
raise TypeError(
msg.format(scalar=self._scalar_type.__name__, typ=type(value).__name__)
)
self._data[key] = value
self._maybe_clear_freq()
def _maybe_clear_freq(self):
# inplace operations like __setitem__ may invalidate the freq of
# DatetimeArray and TimedeltaArray
pass
def astype(self, dtype, copy=True):
# Some notes on cases we don't have to handle here in the base class:
# 1. PeriodArray.astype handles period -> period
# 2. DatetimeArray.astype handles conversion between tz.
# 3. DatetimeArray.astype handles datetime -> period
from pandas import Categorical
dtype = pandas_dtype(dtype)
if is_object_dtype(dtype):
return self._box_values(self.asi8)
elif is_string_dtype(dtype) and not is_categorical_dtype(dtype):
return self._format_native_types()
elif is_integer_dtype(dtype):
# we deliberately ignore int32 vs. int64 here.
# See https://github.com/pandas-dev/pandas/issues/24381 for more.
values = self.asi8
if is_unsigned_integer_dtype(dtype):
# Again, we ignore int32 vs. int64
values = values.view("uint64")
if copy:
values = values.copy()
return values
elif (
is_datetime_or_timedelta_dtype(dtype)
and not is_dtype_equal(self.dtype, dtype)
) or is_float_dtype(dtype):
# disallow conversion between datetime/timedelta,
# and conversions for any datetimelike to float
msg = "Cannot cast {name} to dtype {dtype}"
raise TypeError(msg.format(name=type(self).__name__, dtype=dtype))
elif is_categorical_dtype(dtype):
return Categorical(self, dtype=dtype)
else:
return np.asarray(self, dtype=dtype)
def view(self, dtype=None):
if dtype is None or dtype is self.dtype:
return type(self)(self._data, dtype=self.dtype)
return self._data.view(dtype=dtype)
# ------------------------------------------------------------------
# ExtensionArray Interface
def unique(self):
result = unique1d(self.asi8)
return type(self)(result, dtype=self.dtype)
def _validate_fill_value(self, fill_value):
"""
If a fill_value is passed to `take` convert it to an i8 representation,
raising ValueError if this is not possible.
Parameters
----------
fill_value : object
Returns
-------
fill_value : np.int64
Raises
------
ValueError
"""
raise AbstractMethodError(self)
def take(self, indices, allow_fill=False, fill_value=None):
if allow_fill:
fill_value = self._validate_fill_value(fill_value)
new_values = take(
self.asi8, indices, allow_fill=allow_fill, fill_value=fill_value
)
return type(self)(new_values, dtype=self.dtype)
@classmethod
def _concat_same_type(cls, to_concat):
dtypes = {x.dtype for x in to_concat}
assert len(dtypes) == 1
dtype = list(dtypes)[0]
values = np.concatenate([x.asi8 for x in to_concat])
return cls(values, dtype=dtype)
def copy(self):
values = self.asi8.copy()
return type(self)._simple_new(values, dtype=self.dtype, freq=self.freq)
def _values_for_factorize(self):
return self.asi8, iNaT
@classmethod
def _from_factorized(cls, values, original):
return cls(values, dtype=original.dtype)
def _values_for_argsort(self):
return self._data
# ------------------------------------------------------------------
# Additional array methods
# These are not part of the EA API, but we implement them because
# pandas assumes they're there.
def searchsorted(self, value, side="left", sorter=None):
"""
Find indices where elements should be inserted to maintain order.
Find the indices into a sorted array `self` such that, if the
corresponding elements in `value` were inserted before the indices,
the order of `self` would be preserved.
Parameters
----------
value : array_like
Values to insert into `self`.
side : {'left', 'right'}, optional
If 'left', the index of the first suitable location found is given.
If 'right', return the last such index. If there is no suitable
index, return either 0 or N (where N is the length of `self`).
sorter : 1-D array_like, optional
Optional array of integer indices that sort `self` into ascending
order. They are typically the result of ``np.argsort``.
Returns
-------
indices : array of ints
Array of insertion points with the same shape as `value`.
"""
if isinstance(value, str):
value = self._scalar_from_string(value)
if not (isinstance(value, (self._scalar_type, type(self))) or isna(value)):
raise ValueError(
"Unexpected type for 'value': {valtype}".format(valtype=type(value))
)
self._check_compatible_with(value)
if isinstance(value, type(self)):
value = value.asi8
else:
value = self._unbox_scalar(value)
return self.asi8.searchsorted(value, side=side, sorter=sorter)
def repeat(self, repeats, *args, **kwargs):
"""
Repeat elements of an array.
See Also
--------
numpy.ndarray.repeat
"""
nv.validate_repeat(args, kwargs)
values = self._data.repeat(repeats)
return type(self)(values.view("i8"), dtype=self.dtype)
def value_counts(self, dropna=False):
"""
Return a Series containing counts of unique values.
Parameters
----------
dropna : bool, default True
Don't include counts of NaT values.
Returns
-------
Series
"""
from pandas import Series, Index
if dropna:
values = self[~self.isna()]._data
else:
values = self._data
cls = type(self)
result = value_counts(values, sort=False, dropna=dropna)
index = Index(
cls(result.index.view("i8"), dtype=self.dtype), name=result.index.name
)
return Series(result.values, index=index, name=result.name)
def map(self, mapper):
# TODO(GH-23179): Add ExtensionArray.map
# Need to figure out if we want ExtensionArray.map first.
# If so, then we can refactor IndexOpsMixin._map_values to
# a standalone function and call from here..
# Else, just rewrite _map_infer_values to do the right thing.
from pandas import Index
return Index(self).map(mapper).array
# ------------------------------------------------------------------
# Null Handling
def isna(self):
return self._isnan
@property # NB: override with cache_readonly in immutable subclasses
def _isnan(self):
"""
return if each value is nan
"""
return self.asi8 == iNaT
@property # NB: override with cache_readonly in immutable subclasses
def _hasnans(self):
"""
return if I have any nans; enables various perf speedups
"""
return bool(self._isnan.any())
def _maybe_mask_results(self, result, fill_value=iNaT, convert=None):
"""
Parameters
----------
result : a ndarray
fill_value : object, default iNaT
convert : str, dtype or None
Returns
-------
result : ndarray with values replace by the fill_value
mask the result if needed, convert to the provided dtype if its not
None
This is an internal routine.
"""
if self._hasnans:
if convert:
result = result.astype(convert)
if fill_value is None:
fill_value = np.nan
result[self._isnan] = fill_value
return result
def fillna(self, value=None, method=None, limit=None):
# TODO(GH-20300): remove this
# Just overriding to ensure that we avoid an astype(object).
# Either 20300 or a `_values_for_fillna` would avoid this duplication.
if isinstance(value, ABCSeries):
value = value.array
value, method = validate_fillna_kwargs(value, method)
mask = self.isna()
if is_array_like(value):
if len(value) != len(self):
raise ValueError(
"Length of 'value' does not match. Got ({}) "
" expected {}".format(len(value), len(self))
)
value = value[mask]
if mask.any():
if method is not None:
if method == "pad":
func = missing.pad_1d
else:
func = missing.backfill_1d
values = self._data
if not is_period_dtype(self):
# For PeriodArray self._data is i8, which gets copied
# by `func`. Otherwise we need to make a copy manually
# to avoid modifying `self` in-place.
values = values.copy()
new_values = func(values, limit=limit, mask=mask)
if is_datetime64tz_dtype(self):
# we need to pass int64 values to the constructor to avoid
# re-localizing incorrectly
new_values = new_values.view("i8")
new_values = type(self)(new_values, dtype=self.dtype)
else:
# fill with value
new_values = self.copy()
new_values[mask] = value
else:
new_values = self.copy()
return new_values
# ------------------------------------------------------------------
# Frequency Properties/Methods
@property
def freq(self):
"""
Return the frequency object if it is set, otherwise None.
"""
return self._freq
@freq.setter
def freq(self, value):
if value is not None:
value = frequencies.to_offset(value)
self._validate_frequency(self, value)
self._freq = value
@property
def freqstr(self):
"""
Return the frequency object as a string if its set, otherwise None
"""
if self.freq is None:
return None
return self.freq.freqstr
@property # NB: override with cache_readonly in immutable subclasses
def inferred_freq(self):
"""
Tryies to return a string representing a frequency guess,
generated by infer_freq. Returns None if it can't autodetect the
frequency.
"""
try:
return frequencies.infer_freq(self)
except ValueError:
return None
@property # NB: override with cache_readonly in immutable subclasses
def _resolution(self):
return frequencies.Resolution.get_reso_from_freq(self.freqstr)
@property # NB: override with cache_readonly in immutable subclasses
def resolution(self):
"""
Returns day, hour, minute, second, millisecond or microsecond
"""
return frequencies.Resolution.get_str(self._resolution)
@classmethod
def _validate_frequency(cls, index, freq, **kwargs):
"""
Validate that a frequency is compatible with the values of a given
Datetime Array/Index or Timedelta Array/Index
Parameters
----------
index : DatetimeIndex or TimedeltaIndex
The index on which to determine if the given frequency is valid
freq : DateOffset
The frequency to validate
"""
if is_period_dtype(cls):
# Frequency validation is not meaningful for Period Array/Index
return None
inferred = index.inferred_freq
if index.size == 0 or inferred == freq.freqstr:
return None
try:
on_freq = cls._generate_range(
start=index[0], end=None, periods=len(index), freq=freq, **kwargs
)
if not np.array_equal(index.asi8, on_freq.asi8):
raise ValueError
except ValueError as e:
if "non-fixed" in str(e):
# non-fixed frequencies are not meaningful for timedelta64;
# we retain that error message
raise e
# GH#11587 the main way this is reached is if the `np.array_equal`
# check above is False. This can also be reached if index[0]
# is `NaT`, in which case the call to `cls._generate_range` will
# raise a ValueError, which we re-raise with a more targeted
# message.
raise ValueError(
"Inferred frequency {infer} from passed values "
"does not conform to passed frequency {passed}".format(
infer=inferred, passed=freq.freqstr
)
)
# monotonicity/uniqueness properties are called via frequencies.infer_freq,
# see GH#23789
@property
def _is_monotonic_increasing(self):
return algos.is_monotonic(self.asi8, timelike=True)[0]
@property
def _is_monotonic_decreasing(self):
return algos.is_monotonic(self.asi8, timelike=True)[1]
@property
def _is_unique(self):
return len(unique1d(self.asi8)) == len(self)
# ------------------------------------------------------------------
# Arithmetic Methods
# pow is invalid for all three subclasses; TimedeltaArray will override
# the multiplication and division ops
__pow__ = make_invalid_op("__pow__")
__rpow__ = make_invalid_op("__rpow__")
__mul__ = make_invalid_op("__mul__")
__rmul__ = make_invalid_op("__rmul__")
__truediv__ = make_invalid_op("__truediv__")
__rtruediv__ = make_invalid_op("__rtruediv__")
__floordiv__ = make_invalid_op("__floordiv__")
__rfloordiv__ = make_invalid_op("__rfloordiv__")
__mod__ = make_invalid_op("__mod__")
__rmod__ = make_invalid_op("__rmod__")
__divmod__ = make_invalid_op("__divmod__")
__rdivmod__ = make_invalid_op("__rdivmod__")
def _add_datetimelike_scalar(self, other):
# Overriden by TimedeltaArray
raise TypeError(
"cannot add {cls} and {typ}".format(
cls=type(self).__name__, typ=type(other).__name__
)
)
_add_datetime_arraylike = _add_datetimelike_scalar
def _sub_datetimelike_scalar(self, other):
# Overridden by DatetimeArray
assert other is not NaT
raise TypeError(
"cannot subtract a datelike from a {cls}".format(cls=type(self).__name__)
)
_sub_datetime_arraylike = _sub_datetimelike_scalar
def _sub_period(self, other):
# Overriden by PeriodArray
raise TypeError(
"cannot subtract Period from a {cls}".format(cls=type(self).__name__)
)
def _add_offset(self, offset):
raise AbstractMethodError(self)
def _add_delta(self, other):
"""
Add a timedelta-like, Tick or TimedeltaIndex-like object
to self, yielding an int64 numpy array
Parameters
----------
delta : {timedelta, np.timedelta64, Tick,
TimedeltaIndex, ndarray[timedelta64]}
Returns
-------
result : ndarray[int64]
Notes
-----
The result's name is set outside of _add_delta by the calling
method (__add__ or __sub__), if necessary (i.e. for Indexes).
"""
if isinstance(other, (Tick, timedelta, np.timedelta64)):
new_values = self._add_timedeltalike_scalar(other)
elif is_timedelta64_dtype(other):
# ndarray[timedelta64] or TimedeltaArray/index
new_values = self._add_delta_tdi(other)
return new_values
def _add_timedeltalike_scalar(self, other):
"""
Add a delta of a timedeltalike
return the i8 result view
"""
if isna(other):
# i.e np.timedelta64("NaT"), not recognized by delta_to_nanoseconds
new_values = np.empty(len(self), dtype="i8")
new_values[:] = iNaT
return new_values
inc = delta_to_nanoseconds(other)
new_values = checked_add_with_arr(self.asi8, inc, arr_mask=self._isnan).view(
"i8"
)
new_values = self._maybe_mask_results(new_values)
return new_values.view("i8")
def _add_delta_tdi(self, other):
"""
Add a delta of a TimedeltaIndex
return the i8 result view
"""
if len(self) != len(other):
raise ValueError("cannot add indices of unequal length")
if isinstance(other, np.ndarray):
# ndarray[timedelta64]; wrap in TimedeltaIndex for op
from pandas.core.arrays import TimedeltaArray
other = TimedeltaArray._from_sequence(other)
self_i8 = self.asi8
other_i8 = other.asi8
new_values = checked_add_with_arr(
self_i8, other_i8, arr_mask=self._isnan, b_mask=other._isnan
)
if self._hasnans or other._hasnans:
mask = (self._isnan) | (other._isnan)
new_values[mask] = iNaT
return new_values.view("i8")
def _add_nat(self):
"""
Add pd.NaT to self
"""
if is_period_dtype(self):
raise TypeError(
"Cannot add {cls} and {typ}".format(
cls=type(self).__name__, typ=type(NaT).__name__
)
)
# GH#19124 pd.NaT is treated like a timedelta for both timedelta
# and datetime dtypes
result = np.zeros(len(self), dtype=np.int64)
result.fill(iNaT)
return type(self)(result, dtype=self.dtype, freq=None)
def _sub_nat(self):
"""
Subtract pd.NaT from self
"""
# GH#19124 Timedelta - datetime is not in general well-defined.
# We make an exception for pd.NaT, which in this case quacks
# like a timedelta.
# For datetime64 dtypes by convention we treat NaT as a datetime, so
# this subtraction returns a timedelta64 dtype.
# For period dtype, timedelta64 is a close-enough return dtype.
result = np.zeros(len(self), dtype=np.int64)
result.fill(iNaT)
return result.view("timedelta64[ns]")
def _sub_period_array(self, other):
"""
Subtract a Period Array/Index from self. This is only valid if self
is itself a Period Array/Index, raises otherwise. Both objects must
have the same frequency.
Parameters
----------
other : PeriodIndex or PeriodArray
Returns
-------
result : np.ndarray[object]
Array of DateOffset objects; nulls represented by NaT.
"""
if not is_period_dtype(self):
raise TypeError(
"cannot subtract {dtype}-dtype from {cls}".format(
dtype=other.dtype, cls=type(self).__name__
)
)
if len(self) != len(other):
raise ValueError("cannot subtract arrays/indices of unequal length")
if self.freq != other.freq:
msg = DIFFERENT_FREQ.format(
cls=type(self).__name__, own_freq=self.freqstr, other_freq=other.freqstr
)
raise IncompatibleFrequency(msg)
new_values = checked_add_with_arr(
self.asi8, -other.asi8, arr_mask=self._isnan, b_mask=other._isnan
)
new_values = np.array([self.freq.base * x for x in new_values])
if self._hasnans or other._hasnans:
mask = (self._isnan) | (other._isnan)
new_values[mask] = NaT
return new_values
def _addsub_int_array(self, other, op):
"""
Add or subtract array-like of integers equivalent to applying
`_time_shift` pointwise.
Parameters
----------
other : Index, ExtensionArray, np.ndarray
integer-dtype
op : {operator.add, operator.sub}
Returns
-------
result : same class as self
"""
# _addsub_int_array is overriden by PeriodArray
assert not is_period_dtype(self)
assert op in [operator.add, operator.sub]
if self.freq is None:
# GH#19123
raise NullFrequencyError("Cannot shift with no freq")
elif isinstance(self.freq, Tick):
# easy case where we can convert to timedelta64 operation
td = Timedelta(self.freq)
return op(self, td * other)
# We should only get here with DatetimeIndex; dispatch
# to _addsub_offset_array
assert not is_timedelta64_dtype(self)
return op(self, np.array(other) * self.freq)
def _addsub_offset_array(self, other, op):
"""
Add or subtract array-like of DateOffset objects
Parameters
----------
other : Index, np.ndarray
object-dtype containing pd.DateOffset objects
op : {operator.add, operator.sub}
Returns
-------
result : same class as self
"""
assert op in [operator.add, operator.sub]
if len(other) == 1:
return op(self, other[0])
warnings.warn(
"Adding/subtracting array of DateOffsets to "
"{cls} not vectorized".format(cls=type(self).__name__),
PerformanceWarning,
)
# For EA self.astype('O') returns a numpy array, not an Index
left = self.astype("O")
res_values = op(left, np.array(other))
kwargs = {}
if not is_period_dtype(self):
kwargs["freq"] = "infer"
return self._from_sequence(res_values, **kwargs)
def _time_shift(self, periods, freq=None):
"""
Shift each value by `periods`.
Note this is different from ExtensionArray.shift, which
shifts the *position* of each element, padding the end with
missing values.
Parameters
----------
periods : int
Number of periods to shift by.
freq : pandas.DateOffset, pandas.Timedelta, or str
Frequency increment to shift by.
"""
if freq is not None and freq != self.freq:
if isinstance(freq, str):
freq = frequencies.to_offset(freq)
offset = periods * freq
result = self + offset
return result
if periods == 0:
# immutable so OK
return self.copy()
if self.freq is None:
raise NullFrequencyError("Cannot shift with no freq")
start = self[0] + periods * self.freq
end = self[-1] + periods * self.freq
# Note: in the DatetimeTZ case, _generate_range will infer the
# appropriate timezone from `start` and `end`, so tz does not need
# to be passed explicitly.
return self._generate_range(start=start, end=end, periods=None, freq=self.freq)
def __add__(self, other):
other = lib.item_from_zerodim(other)
if isinstance(other, (ABCSeries, ABCDataFrame, ABCIndexClass)):
return NotImplemented
# scalar others
elif other is NaT:
result = self._add_nat()
elif isinstance(other, (Tick, timedelta, np.timedelta64)):
result = self._add_delta(other)
elif isinstance(other, DateOffset):
# specifically _not_ a Tick
result = self._add_offset(other)
elif isinstance(other, (datetime, np.datetime64)):
result = self._add_datetimelike_scalar(other)
elif lib.is_integer(other):
# This check must come after the check for np.timedelta64
# as is_integer returns True for these
if not is_period_dtype(self):
maybe_integer_op_deprecated(self)
result = self._time_shift(other)
# array-like others
elif is_timedelta64_dtype(other):
# TimedeltaIndex, ndarray[timedelta64]
result = self._add_delta(other)
elif is_offsetlike(other):
# Array/Index of DateOffset objects
result = self._addsub_offset_array(other, operator.add)
elif is_datetime64_dtype(other) or is_datetime64tz_dtype(other):
# DatetimeIndex, ndarray[datetime64]
return self._add_datetime_arraylike(other)
elif is_integer_dtype(other):
if not is_period_dtype(self):
maybe_integer_op_deprecated(self)
result = self._addsub_int_array(other, operator.add)
else:
# Includes Categorical, other ExtensionArrays
# For PeriodDtype, if self is a TimedeltaArray and other is a
# PeriodArray with a timedelta-like (i.e. Tick) freq, this
# operation is valid. Defer to the PeriodArray implementation.
# In remaining cases, this will end up raising TypeError.
return NotImplemented
if is_timedelta64_dtype(result) and isinstance(result, np.ndarray):
from pandas.core.arrays import TimedeltaArray
return TimedeltaArray(result)
return result
def __radd__(self, other):
# alias for __add__
return self.__add__(other)
def __sub__(self, other):
other = lib.item_from_zerodim(other)
if isinstance(other, (ABCSeries, ABCDataFrame, ABCIndexClass)):
return NotImplemented
# scalar others
elif other is NaT:
result = self._sub_nat()
elif isinstance(other, (Tick, timedelta, np.timedelta64)):
result = self._add_delta(-other)
elif isinstance(other, DateOffset):
# specifically _not_ a Tick
result = self._add_offset(-other)
elif isinstance(other, (datetime, np.datetime64)):
result = self._sub_datetimelike_scalar(other)
elif lib.is_integer(other):
# This check must come after the check for np.timedelta64
# as is_integer returns True for these
if not is_period_dtype(self):
maybe_integer_op_deprecated(self)
result = self._time_shift(-other)
elif isinstance(other, Period):
result = self._sub_period(other)
# array-like others
elif is_timedelta64_dtype(other):
# TimedeltaIndex, ndarray[timedelta64]
result = self._add_delta(-other)
elif is_offsetlike(other):
# Array/Index of DateOffset objects
result = self._addsub_offset_array(other, operator.sub)
elif is_datetime64_dtype(other) or is_datetime64tz_dtype(other):
# DatetimeIndex, ndarray[datetime64]
result = self._sub_datetime_arraylike(other)
elif is_period_dtype(other):
# PeriodIndex
result = self._sub_period_array(other)
elif is_integer_dtype(other):
if not is_period_dtype(self):
maybe_integer_op_deprecated(self)
result = self._addsub_int_array(other, operator.sub)
else:
# Includes ExtensionArrays, float_dtype
return NotImplemented
if is_timedelta64_dtype(result) and isinstance(result, np.ndarray):
from pandas.core.arrays import TimedeltaArray
return TimedeltaArray(result)
return result
def __rsub__(self, other):
if is_datetime64_any_dtype(other) and is_timedelta64_dtype(self.dtype):
# ndarray[datetime64] cannot be subtracted from self, so
# we need to wrap in DatetimeArray/Index and flip the operation
if lib.is_scalar(other):
# i.e. np.datetime64 object
return Timestamp(other) - self
if not isinstance(other, DatetimeLikeArrayMixin):
# Avoid down-casting DatetimeIndex
from pandas.core.arrays import DatetimeArray
other = DatetimeArray(other)
return other - self
elif (
is_datetime64_any_dtype(self.dtype)
and hasattr(other, "dtype")
and not is_datetime64_any_dtype(other.dtype)
):
# GH#19959 datetime - datetime is well-defined as timedelta,
# but any other type - datetime is not well-defined.
raise TypeError(
"cannot subtract {cls} from {typ}".format(
cls=type(self).__name__, typ=type(other).__name__
)
)
elif is_period_dtype(self.dtype) and is_timedelta64_dtype(other):
# TODO: Can we simplify/generalize these cases at all?
raise TypeError(
"cannot subtract {cls} from {dtype}".format(
cls=type(self).__name__, dtype=other.dtype
)
)
elif is_timedelta64_dtype(self.dtype):
if lib.is_integer(other) or is_integer_dtype(other):
# need to subtract before negating, since that flips freq
# -self flips self.freq, messing up results
return -(self - other)
return (-self) + other
return -(self - other)
# FIXME: DTA/TDA/PA inplace methods should actually be inplace, GH#24115
def __iadd__(self, other):
# alias for __add__
return self.__add__(other)
def __isub__(self, other):
# alias for __sub__
return self.__sub__(other)
# --------------------------------------------------------------
# Comparison Methods
def _ensure_localized(
self, arg, ambiguous="raise", nonexistent="raise", from_utc=False
):
"""
Ensure that we are re-localized.
This is for compat as we can then call this on all datetimelike
arrays generally (ignored for Period/Timedelta)
Parameters
----------
arg : Union[DatetimeLikeArray, DatetimeIndexOpsMixin, ndarray]
ambiguous : str, bool, or bool-ndarray, default 'raise'
nonexistent : str, default 'raise'
from_utc : bool, default False
If True, localize the i8 ndarray to UTC first before converting to
the appropriate tz. If False, localize directly to the tz.
Returns
-------
localized array
"""
# reconvert to local tz
tz = getattr(self, "tz", None)
if tz is not None:
if not isinstance(arg, type(self)):
arg = self._simple_new(arg)
if from_utc:
arg = arg.tz_localize("UTC").tz_convert(self.tz)
else:
arg = arg.tz_localize(
self.tz, ambiguous=ambiguous, nonexistent=nonexistent
)
return arg
# --------------------------------------------------------------
# Reductions
def _reduce(self, name, axis=0, skipna=True, **kwargs):
op = getattr(self, name, None)
if op:
return op(skipna=skipna, **kwargs)
else:
return super()._reduce(name, skipna, **kwargs)
def min(self, axis=None, skipna=True, *args, **kwargs):
"""
Return the minimum value of the Array or minimum along
an axis.
See Also
--------
numpy.ndarray.min
Index.min : Return the minimum value in an Index.
Series.min : Return the minimum value in a Series.
"""
nv.validate_min(args, kwargs)
nv.validate_minmax_axis(axis)
result = nanops.nanmin(self.asi8, skipna=skipna, mask=self.isna())
if isna(result):
# Period._from_ordinal does not handle np.nan gracefully
return NaT
return self._box_func(result)
def max(self, axis=None, skipna=True, *args, **kwargs):
"""
Return the maximum value of the Array or maximum along
an axis.
See Also
--------
numpy.ndarray.max
Index.max : Return the maximum value in an Index.
Series.max : Return the maximum value in a Series.
"""
# TODO: skipna is broken with max.
# See https://github.com/pandas-dev/pandas/issues/24265
nv.validate_max(args, kwargs)
nv.validate_minmax_axis(axis)
mask = self.isna()
if skipna:
values = self[~mask].asi8
elif mask.any():
return NaT
else:
values = self.asi8
if not len(values):
# short-circuit for empty max / min
return NaT
result = nanops.nanmax(values, skipna=skipna)
# Don't have to worry about NA `result`, since no NA went in.
return self._box_func(result)
def mean(self, skipna=True):
"""
Return the mean value of the Array.
.. versionadded:: 0.25.0
Parameters
----------
skipna : bool, default True
Whether to ignore any NaT elements.
Returns
-------
scalar
Timestamp or Timedelta.
See Also
--------
numpy.ndarray.mean : Returns the average of array elements along a given axis.
Series.mean : Return the mean value in a Series.
Notes
-----
mean is only defined for Datetime and Timedelta dtypes, not for Period.
"""
if is_period_dtype(self):
# See discussion in GH#24757
raise TypeError(
"mean is not implemented for {cls} since the meaning is "
"ambiguous. An alternative is "
"obj.to_timestamp(how='start').mean()".format(cls=type(self).__name__)
)
mask = self.isna()
if skipna:
values = self[~mask]
elif mask.any():
return NaT
else:
values = self
if not len(values):
# short-circut for empty max / min
return NaT
result = nanops.nanmean(values.view("i8"), skipna=skipna)
# Don't have to worry about NA `result`, since no NA went in.
return self._box_func(result)
# -------------------------------------------------------------------
# Shared Constructor Helpers
def validate_periods(periods):
"""
If a `periods` argument is passed to the Datetime/Timedelta Array/Index
constructor, cast it to an integer.
Parameters
----------
periods : None, float, int
Returns
-------
periods : None or int
Raises
------
TypeError
if periods is None, float, or int
"""
if periods is not None:
if lib.is_float(periods):
periods = int(periods)
elif not lib.is_integer(periods):
raise TypeError(
"periods must be a number, got {periods}".format(periods=periods)
)
return periods
def validate_endpoints(closed):
"""
Check that the `closed` argument is among [None, "left", "right"]
Parameters
----------
closed : {None, "left", "right"}
Returns
-------
left_closed : bool
right_closed : bool
Raises
------
ValueError : if argument is not among valid values
"""
left_closed = False
right_closed = False
if closed is None:
left_closed = True
right_closed = True
elif closed == "left":
left_closed = True
elif closed == "right":
right_closed = True
else:
raise ValueError("Closed has to be either 'left', 'right' or None")
return left_closed, right_closed
def validate_inferred_freq(freq, inferred_freq, freq_infer):
"""
If the user passes a freq and another freq is inferred from passed data,
require that they match.
Parameters
----------
freq : DateOffset or None
inferred_freq : DateOffset or None
freq_infer : bool
Returns
-------
freq : DateOffset or None
freq_infer : bool
Notes
-----
We assume at this point that `maybe_infer_freq` has been called, so
`freq` is either a DateOffset object or None.
"""
if inferred_freq is not None:
if freq is not None and freq != inferred_freq:
raise ValueError(
"Inferred frequency {inferred} from passed "
"values does not conform to passed frequency "
"{passed}".format(inferred=inferred_freq, passed=freq.freqstr)
)
elif freq is None:
freq = inferred_freq
freq_infer = False
return freq, freq_infer
def maybe_infer_freq(freq):
"""
Comparing a DateOffset to the string "infer" raises, so we need to
be careful about comparisons. Make a dummy variable `freq_infer` to
signify the case where the given freq is "infer" and set freq to None
to avoid comparison trouble later on.
Parameters
----------
freq : {DateOffset, None, str}
Returns
-------
freq : {DateOffset, None}
freq_infer : bool
"""
freq_infer = False
if not isinstance(freq, DateOffset):
# if a passed freq is None, don't infer automatically
if freq != "infer":
freq = frequencies.to_offset(freq)
else:
freq_infer = True
freq = None
return freq, freq_infer
def _ensure_datetimelike_to_i8(other, to_utc=False):
"""
Helper for coercing an input scalar or array to i8.
Parameters
----------
other : 1d array
to_utc : bool, default False
If True, convert the values to UTC before extracting the i8 values
If False, extract the i8 values directly.
Returns
-------
i8 1d array
"""
from pandas import Index
if lib.is_scalar(other) and isna(other):
return iNaT
elif isinstance(other, (ABCPeriodArray, ABCIndexClass, DatetimeLikeArrayMixin)):
# convert tz if needed
if getattr(other, "tz", None) is not None:
if to_utc:
other = other.tz_convert("UTC")
else:
other = other.tz_localize(None)
else:
try:
return np.array(other, copy=False).view("i8")
except TypeError:
# period array cannot be coerced to int
other = Index(other)
return other.asi8
| BugsInPy/BugsInPy/temp/projects/pandas/bug-129-fixed/pandas/pandas/core/arrays/datetimelike.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-129-buggy/pandas/pandas/core/arrays/datetimelike.py |
pandas-bug-137 | import operator
from shutil import get_terminal_size
import textwrap
from typing import Type, Union, cast
from warnings import warn
import numpy as np
from pandas._config import get_option
from pandas._libs import algos as libalgos, hashtable as htable, lib
from pandas.compat.numpy import function as nv
from pandas.util._decorators import (
Appender,
Substitution,
cache_readonly,
deprecate_kwarg,
)
from pandas.util._validators import validate_bool_kwarg, validate_fillna_kwargs
from pandas.core.dtypes.cast import coerce_indexer_dtype, maybe_infer_to_datetimelike
from pandas.core.dtypes.common import (
ensure_int64,
ensure_object,
ensure_platform_int,
is_categorical_dtype,
is_datetime64_dtype,
is_datetimelike,
is_dict_like,
is_dtype_equal,
is_extension_array_dtype,
is_float_dtype,
is_integer_dtype,
is_iterator,
is_list_like,
is_object_dtype,
is_scalar,
is_sequence,
is_timedelta64_dtype,
)
from pandas.core.dtypes.dtypes import CategoricalDtype
from pandas.core.dtypes.generic import ABCDataFrame, ABCIndexClass, ABCSeries
from pandas.core.dtypes.inference import is_hashable
from pandas.core.dtypes.missing import isna, notna
from pandas._typing import ArrayLike, Dtype, Ordered
from pandas.core import ops
from pandas.core.accessor import PandasDelegate, delegate_names
import pandas.core.algorithms as algorithms
from pandas.core.algorithms import (
_get_data_algo,
_hashtables,
factorize,
take,
take_1d,
unique1d,
)
from pandas.core.base import NoNewAttributesMixin, PandasObject, _shared_docs
import pandas.core.common as com
from pandas.core.construction import extract_array, sanitize_array
from pandas.core.missing import interpolate_2d
from pandas.core.sorting import nargsort
from pandas.io.formats import console
from .base import ExtensionArray, _extension_array_shared_docs
_take_msg = textwrap.dedent(
"""\
Interpreting negative values in 'indexer' as missing values.
In the future, this will change to meaning positional indices
from the right.
Use 'allow_fill=True' to retain the previous behavior and silence this
warning.
Use 'allow_fill=False' to accept the new behavior."""
)
def _cat_compare_op(op):
opname = "__{op}__".format(op=op.__name__)
def f(self, other):
# On python2, you can usually compare any type to any type, and
# Categoricals can be seen as a custom type, but having different
# results depending whether categories are the same or not is kind of
# insane, so be a bit stricter here and use the python3 idea of
# comparing only things of equal type.
if isinstance(other, (ABCDataFrame, ABCSeries, ABCIndexClass)):
return NotImplemented
other = lib.item_from_zerodim(other)
if is_list_like(other) and len(other) != len(self):
# TODO: Could this fail if the categories are listlike objects?
raise ValueError("Lengths must match.")
if not self.ordered:
if opname in ["__lt__", "__gt__", "__le__", "__ge__"]:
raise TypeError(
"Unordered Categoricals can only compare equality or not"
)
if isinstance(other, Categorical):
# Two Categoricals can only be be compared if the categories are
# the same (maybe up to ordering, depending on ordered)
msg = "Categoricals can only be compared if 'categories' are the same."
if len(self.categories) != len(other.categories):
raise TypeError(msg + " Categories are different lengths")
elif self.ordered and not (self.categories == other.categories).all():
raise TypeError(msg)
elif not set(self.categories) == set(other.categories):
raise TypeError(msg)
if not (self.ordered == other.ordered):
raise TypeError(
"Categoricals can only be compared if 'ordered' is the same"
)
if not self.ordered and not self.categories.equals(other.categories):
# both unordered and different order
other_codes = _get_codes_for_values(other, self.categories)
else:
other_codes = other._codes
mask = (self._codes == -1) | (other_codes == -1)
f = getattr(self._codes, opname)
ret = f(other_codes)
if mask.any():
# In other series, the leads to False, so do that here too
ret[mask] = False
return ret
if is_scalar(other):
if other in self.categories:
i = self.categories.get_loc(other)
ret = getattr(self._codes, opname)(i)
# check for NaN in self
mask = self._codes == -1
ret[mask] = False
return ret
else:
if opname == "__eq__":
return np.repeat(False, len(self))
elif opname == "__ne__":
return np.repeat(True, len(self))
else:
msg = (
"Cannot compare a Categorical for op {op} with a "
"scalar, which is not a category."
)
raise TypeError(msg.format(op=opname))
else:
# allow categorical vs object dtype array comparisons for equality
# these are only positional comparisons
if opname in ["__eq__", "__ne__"]:
return getattr(np.array(self), opname)(np.array(other))
msg = (
"Cannot compare a Categorical for op {op} with type {typ}."
"\nIf you want to compare values, use 'np.asarray(cat) "
"<op> other'."
)
raise TypeError(msg.format(op=opname, typ=type(other)))
f.__name__ = opname
return f
def contains(cat, key, container):
"""
Helper for membership check for ``key`` in ``cat``.
This is a helper method for :method:`__contains__`
and :class:`CategoricalIndex.__contains__`.
Returns True if ``key`` is in ``cat.categories`` and the
location of ``key`` in ``categories`` is in ``container``.
Parameters
----------
cat : :class:`Categorical`or :class:`categoricalIndex`
key : a hashable object
The key to check membership for.
container : Container (e.g. list-like or mapping)
The container to check for membership in.
Returns
-------
is_in : bool
True if ``key`` is in ``self.categories`` and location of
``key`` in ``categories`` is in ``container``, else False.
Notes
-----
This method does not check for NaN values. Do that separately
before calling this method.
"""
hash(key)
# get location of key in categories.
# If a KeyError, the key isn't in categories, so logically
# can't be in container either.
try:
loc = cat.categories.get_loc(key)
except (KeyError, TypeError):
return False
# loc is the location of key in categories, but also the *value*
# for key in container. So, `key` may be in categories,
# but still not in `container`. Example ('b' in categories,
# but not in values):
# 'b' in Categorical(['a'], categories=['a', 'b']) # False
if is_scalar(loc):
return loc in container
else:
# if categories is an IntervalIndex, loc is an array.
return any(loc_ in container for loc_ in loc)
_codes_doc = """
The category codes of this categorical.
Level codes are an array if integer which are the positions of the real
values in the categories array.
There is not setter, use the other categorical methods and the normal item
setter to change values in the categorical.
"""
class Categorical(ExtensionArray, PandasObject):
"""
Represent a categorical variable in classic R / S-plus fashion.
`Categoricals` can only take on only a limited, and usually fixed, number
of possible values (`categories`). In contrast to statistical categorical
variables, a `Categorical` might have an order, but numerical operations
(additions, divisions, ...) are not possible.
All values of the `Categorical` are either in `categories` or `np.nan`.
Assigning values outside of `categories` will raise a `ValueError`. Order
is defined by the order of the `categories`, not lexical order of the
values.
Parameters
----------
values : list-like
The values of the categorical. If categories are given, values not in
categories will be replaced with NaN.
categories : Index-like (unique), optional
The unique categories for this categorical. If not given, the
categories are assumed to be the unique values of `values` (sorted, if
possible, otherwise in the order in which they appear).
ordered : bool, default False
Whether or not this categorical is treated as a ordered categorical.
If True, the resulting categorical will be ordered.
An ordered categorical respects, when sorted, the order of its
`categories` attribute (which in turn is the `categories` argument, if
provided).
dtype : CategoricalDtype
An instance of ``CategoricalDtype`` to use for this categorical
.. versionadded:: 0.21.0
Attributes
----------
categories : Index
The categories of this categorical
codes : ndarray
The codes (integer positions, which point to the categories) of this
categorical, read only.
ordered : bool
Whether or not this Categorical is ordered.
dtype : CategoricalDtype
The instance of ``CategoricalDtype`` storing the ``categories``
and ``ordered``.
.. versionadded:: 0.21.0
Methods
-------
from_codes
__array__
Raises
------
ValueError
If the categories do not validate.
TypeError
If an explicit ``ordered=True`` is given but no `categories` and the
`values` are not sortable.
See Also
--------
api.types.CategoricalDtype : Type for categorical data.
CategoricalIndex : An Index with an underlying ``Categorical``.
Notes
-----
See the `user guide
<http://pandas.pydata.org/pandas-docs/stable/user_guide/categorical.html>`_
for more.
Examples
--------
>>> pd.Categorical([1, 2, 3, 1, 2, 3])
[1, 2, 3, 1, 2, 3]
Categories (3, int64): [1, 2, 3]
>>> pd.Categorical(['a', 'b', 'c', 'a', 'b', 'c'])
[a, b, c, a, b, c]
Categories (3, object): [a, b, c]
Ordered `Categoricals` can be sorted according to the custom order
of the categories and can have a min and max value.
>>> c = pd.Categorical(['a', 'b', 'c', 'a', 'b', 'c'], ordered=True,
... categories=['c', 'b', 'a'])
>>> c
[a, b, c, a, b, c]
Categories (3, object): [c < b < a]
>>> c.min()
'c'
"""
# For comparisons, so that numpy uses our implementation if the compare
# ops, which raise
__array_priority__ = 1000
_dtype = CategoricalDtype(ordered=False)
# tolist is not actually deprecated, just suppressed in the __dir__
_deprecations = frozenset(["labels", "tolist"])
_typ = "categorical"
def __init__(
self, values, categories=None, ordered=None, dtype=None, fastpath=False
):
dtype = CategoricalDtype._from_values_or_dtype(
values, categories, ordered, dtype
)
# At this point, dtype is always a CategoricalDtype, but
# we may have dtype.categories be None, and we need to
# infer categories in a factorization step futher below
if fastpath:
self._codes = coerce_indexer_dtype(values, dtype.categories)
self._dtype = self._dtype.update_dtype(dtype)
return
# null_mask indicates missing values we want to exclude from inference.
# This means: only missing values in list-likes (not arrays/ndframes).
null_mask = np.array(False)
# sanitize input
if is_categorical_dtype(values):
if dtype.categories is None:
dtype = CategoricalDtype(values.categories, dtype._ordered)
elif not isinstance(values, (ABCIndexClass, ABCSeries)):
# sanitize_array coerces np.nan to a string under certain versions
# of numpy
values = maybe_infer_to_datetimelike(values, convert_dates=True)
if not isinstance(values, np.ndarray):
values = _convert_to_list_like(values)
# By convention, empty lists result in object dtype:
if len(values) == 0:
sanitize_dtype = "object"
else:
sanitize_dtype = None
null_mask = isna(values)
if null_mask.any():
values = [values[idx] for idx in np.where(~null_mask)[0]]
values = sanitize_array(values, None, dtype=sanitize_dtype)
if dtype.categories is None:
try:
codes, categories = factorize(values, sort=True)
except TypeError:
codes, categories = factorize(values, sort=False)
if dtype._ordered:
# raise, as we don't have a sortable data structure and so
# the user should give us one by specifying categories
raise TypeError(
"'values' is not ordered, please "
"explicitly specify the categories order "
"by passing in a categories argument."
)
except ValueError:
# FIXME
raise NotImplementedError(
"> 1 ndim Categorical are not supported at this time"
)
# we're inferring from values
dtype = CategoricalDtype(categories, dtype._ordered)
elif is_categorical_dtype(values):
old_codes = (
values._values.codes if isinstance(values, ABCSeries) else values.codes
)
codes = _recode_for_categories(
old_codes, values.dtype.categories, dtype.categories
)
else:
codes = _get_codes_for_values(values, dtype.categories)
if null_mask.any():
# Reinsert -1 placeholders for previously removed missing values
full_codes = -np.ones(null_mask.shape, dtype=codes.dtype)
full_codes[~null_mask] = codes
codes = full_codes
self._dtype = self._dtype.update_dtype(dtype)
self._codes = coerce_indexer_dtype(codes, dtype.categories)
@property
def categories(self):
"""
The categories of this categorical.
Setting assigns new values to each category (effectively a rename of
each individual category).
The assigned value has to be a list-like object. All items must be
unique and the number of items in the new categories must be the same
as the number of items in the old categories.
Assigning to `categories` is a inplace operation!
Raises
------
ValueError
If the new categories do not validate as categories or if the
number of new categories is unequal the number of old categories
See Also
--------
rename_categories
reorder_categories
add_categories
remove_categories
remove_unused_categories
set_categories
"""
return self.dtype.categories
@categories.setter
def categories(self, categories):
new_dtype = CategoricalDtype(categories, ordered=self.ordered)
if self.dtype.categories is not None and len(self.dtype.categories) != len(
new_dtype.categories
):
raise ValueError(
"new categories need to have the same number of "
"items as the old categories!"
)
self._dtype = new_dtype
@property
def ordered(self) -> Ordered:
"""
Whether the categories have an ordered relationship.
"""
return self.dtype._ordered
@property
def dtype(self) -> CategoricalDtype:
"""
The :class:`~pandas.api.types.CategoricalDtype` for this instance.
"""
return self._dtype
@property
def _ndarray_values(self) -> np.ndarray:
return self.codes
@property
def _constructor(self) -> Type["Categorical"]:
return Categorical
@classmethod
def _from_sequence(cls, scalars, dtype=None, copy=False):
return Categorical(scalars, dtype=dtype)
def _formatter(self, boxed=False):
# Defer to CategoricalFormatter's formatter.
return None
def copy(self) -> "Categorical":
"""
Copy constructor.
"""
return self._constructor(
values=self._codes.copy(), dtype=self.dtype, fastpath=True
)
def astype(self, dtype: Dtype, copy: bool = True) -> ArrayLike:
"""
Coerce this type to another dtype
Parameters
----------
dtype : numpy dtype or pandas type
copy : bool, default True
By default, astype always returns a newly allocated object.
If copy is set to False and dtype is categorical, the original
object is returned.
"""
if is_categorical_dtype(dtype):
dtype = cast(Union[str, CategoricalDtype], dtype)
# GH 10696/18593
dtype = self.dtype.update_dtype(dtype)
self = self.copy() if copy else self
if dtype == self.dtype:
return self
return self._set_dtype(dtype)
if is_integer_dtype(dtype) and self.isna().any():
msg = "Cannot convert float NaN to integer"
raise ValueError(msg)
return np.array(self, dtype=dtype, copy=copy)
@cache_readonly
def size(self) -> int:
"""
return the len of myself
"""
return self._codes.size
@cache_readonly
def itemsize(self) -> int:
"""
return the size of a single category
"""
return self.categories.itemsize
def tolist(self) -> list:
"""
Return a list of the values.
These are each a scalar type, which is a Python scalar
(for str, int, float) or a pandas scalar
(for Timestamp/Timedelta/Interval/Period)
"""
return list(self)
to_list = tolist
@property
def base(self) -> None:
"""
compat, we are always our own object
"""
return None
@classmethod
def _from_inferred_categories(
cls, inferred_categories, inferred_codes, dtype, true_values=None
):
"""
Construct a Categorical from inferred values.
For inferred categories (`dtype` is None) the categories are sorted.
For explicit `dtype`, the `inferred_categories` are cast to the
appropriate type.
Parameters
----------
inferred_categories : Index
inferred_codes : Index
dtype : CategoricalDtype or 'category'
true_values : list, optional
If none are provided, the default ones are
"True", "TRUE", and "true."
Returns
-------
Categorical
"""
from pandas import Index, to_numeric, to_datetime, to_timedelta
cats = Index(inferred_categories)
known_categories = (
isinstance(dtype, CategoricalDtype) and dtype.categories is not None
)
if known_categories:
# Convert to a specialized type with `dtype` if specified.
if dtype.categories.is_numeric():
cats = to_numeric(inferred_categories, errors="coerce")
elif is_datetime64_dtype(dtype.categories):
cats = to_datetime(inferred_categories, errors="coerce")
elif is_timedelta64_dtype(dtype.categories):
cats = to_timedelta(inferred_categories, errors="coerce")
elif dtype.categories.is_boolean():
if true_values is None:
true_values = ["True", "TRUE", "true"]
cats = cats.isin(true_values)
if known_categories:
# Recode from observation order to dtype.categories order.
categories = dtype.categories
codes = _recode_for_categories(inferred_codes, cats, categories)
elif not cats.is_monotonic_increasing:
# Sort categories and recode for unknown categories.
unsorted = cats.copy()
categories = cats.sort_values()
codes = _recode_for_categories(inferred_codes, unsorted, categories)
dtype = CategoricalDtype(categories, ordered=False)
else:
dtype = CategoricalDtype(cats, ordered=False)
codes = inferred_codes
return cls(codes, dtype=dtype, fastpath=True)
@classmethod
def from_codes(cls, codes, categories=None, ordered=None, dtype=None):
"""
Make a Categorical type from codes and categories or dtype.
This constructor is useful if you already have codes and
categories/dtype and so do not need the (computation intensive)
factorization step, which is usually done on the constructor.
If your data does not follow this convention, please use the normal
constructor.
Parameters
----------
codes : array-like, integers
An integer array, where each integer points to a category in
categories or dtype.categories, or else is -1 for NaN.
categories : index-like, optional
The categories for the categorical. Items need to be unique.
If the categories are not given here, then they must be provided
in `dtype`.
ordered : bool, optional
Whether or not this categorical is treated as an ordered
categorical. If not given here or in `dtype`, the resulting
categorical will be unordered.
dtype : CategoricalDtype or the string "category", optional
If :class:`CategoricalDtype`, cannot be used together with
`categories` or `ordered`.
.. versionadded:: 0.24.0
When `dtype` is provided, neither `categories` nor `ordered`
should be provided.
Returns
-------
Categorical
Examples
--------
>>> dtype = pd.CategoricalDtype(['a', 'b'], ordered=True)
>>> pd.Categorical.from_codes(codes=[0, 1, 0, 1], dtype=dtype)
[a, b, a, b]
Categories (2, object): [a < b]
"""
dtype = CategoricalDtype._from_values_or_dtype(
categories=categories, ordered=ordered, dtype=dtype
)
if dtype.categories is None:
msg = (
"The categories must be provided in 'categories' or "
"'dtype'. Both were None."
)
raise ValueError(msg)
codes = np.asarray(codes) # #21767
if not is_integer_dtype(codes):
msg = "codes need to be array-like integers"
if is_float_dtype(codes):
icodes = codes.astype("i8")
if (icodes == codes).all():
msg = None
codes = icodes
warn(
(
"float codes will be disallowed in the future and "
"raise a ValueError"
),
FutureWarning,
stacklevel=2,
)
if msg:
raise ValueError(msg)
if len(codes) and (codes.max() >= len(dtype.categories) or codes.min() < -1):
raise ValueError("codes need to be between -1 and len(categories)-1")
return cls(codes, dtype=dtype, fastpath=True)
def _get_codes(self):
"""
Get the codes.
Returns
-------
codes : integer array view
A non writable view of the `codes` array.
"""
v = self._codes.view()
v.flags.writeable = False
return v
def _set_codes(self, codes):
"""
Not settable by the user directly
"""
raise ValueError("cannot set Categorical codes directly")
codes = property(fget=_get_codes, fset=_set_codes, doc=_codes_doc)
def _set_categories(self, categories, fastpath=False):
"""
Sets new categories inplace
Parameters
----------
fastpath : bool, default False
Don't perform validation of the categories for uniqueness or nulls
Examples
--------
>>> c = pd.Categorical(['a', 'b'])
>>> c
[a, b]
Categories (2, object): [a, b]
>>> c._set_categories(pd.Index(['a', 'c']))
>>> c
[a, c]
Categories (2, object): [a, c]
"""
if fastpath:
new_dtype = CategoricalDtype._from_fastpath(categories, self.ordered)
else:
new_dtype = CategoricalDtype(categories, ordered=self.ordered)
if (
not fastpath
and self.dtype.categories is not None
and len(new_dtype.categories) != len(self.dtype.categories)
):
raise ValueError(
"new categories need to have the same number of "
"items than the old categories!"
)
self._dtype = new_dtype
def _set_dtype(self, dtype: CategoricalDtype) -> "Categorical":
"""
Internal method for directly updating the CategoricalDtype
Parameters
----------
dtype : CategoricalDtype
Notes
-----
We don't do any validation here. It's assumed that the dtype is
a (valid) instance of `CategoricalDtype`.
"""
codes = _recode_for_categories(self.codes, self.categories, dtype.categories)
return type(self)(codes, dtype=dtype, fastpath=True)
def set_ordered(self, value, inplace=False):
"""
Set the ordered attribute to the boolean value.
Parameters
----------
value : bool
Set whether this categorical is ordered (True) or not (False).
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to the value.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
new_dtype = CategoricalDtype(self.categories, ordered=value)
cat = self if inplace else self.copy()
cat._dtype = new_dtype
if not inplace:
return cat
def as_ordered(self, inplace=False):
"""
Set the Categorical to be ordered.
Parameters
----------
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to True.
Returns
-------
Categorical
Ordered Categorical.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
return self.set_ordered(True, inplace=inplace)
def as_unordered(self, inplace=False):
"""
Set the Categorical to be unordered.
Parameters
----------
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to False.
Returns
-------
Categorical
Unordered Categorical.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
return self.set_ordered(False, inplace=inplace)
def set_categories(self, new_categories, ordered=None, rename=False, inplace=False):
"""
Set the categories to the specified new_categories.
`new_categories` can include new categories (which will result in
unused categories) or remove old categories (which results in values
set to NaN). If `rename==True`, the categories will simple be renamed
(less or more items than in old categories will result in values set to
NaN or in unused categories respectively).
This method can be used to perform more than one action of adding,
removing, and reordering simultaneously and is therefore faster than
performing the individual steps via the more specialised methods.
On the other hand this methods does not do checks (e.g., whether the
old categories are included in the new categories on a reorder), which
can result in surprising changes, for example when using special string
dtypes on python3, which does not considers a S1 string equal to a
single char python string.
Parameters
----------
new_categories : Index-like
The categories in new order.
ordered : bool, default False
Whether or not the categorical is treated as a ordered categorical.
If not given, do not change the ordered information.
rename : bool, default False
Whether or not the new_categories should be considered as a rename
of the old categories or as reordered categories.
inplace : bool, default False
Whether or not to reorder the categories in-place or return a copy
of this categorical with reordered categories.
Returns
-------
Categorical with reordered categories or None if inplace.
Raises
------
ValueError
If new_categories does not validate as categories
See Also
--------
rename_categories
reorder_categories
add_categories
remove_categories
remove_unused_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if ordered is None:
ordered = self.dtype._ordered
new_dtype = CategoricalDtype(new_categories, ordered=ordered)
cat = self if inplace else self.copy()
if rename:
if cat.dtype.categories is not None and len(new_dtype.categories) < len(
cat.dtype.categories
):
# remove all _codes which are larger and set to -1/NaN
cat._codes[cat._codes >= len(new_dtype.categories)] = -1
else:
codes = _recode_for_categories(
cat.codes, cat.categories, new_dtype.categories
)
cat._codes = codes
cat._dtype = new_dtype
if not inplace:
return cat
def rename_categories(self, new_categories, inplace=False):
"""
Rename categories.
Parameters
----------
new_categories : list-like, dict-like or callable
* list-like: all items must be unique and the number of items in
the new categories must match the existing number of categories.
* dict-like: specifies a mapping from
old categories to new. Categories not contained in the mapping
are passed through and extra categories in the mapping are
ignored.
.. versionadded:: 0.21.0
* callable : a callable that is called on all items in the old
categories and whose return values comprise the new categories.
.. versionadded:: 0.23.0
inplace : bool, default False
Whether or not to rename the categories inplace or return a copy of
this categorical with renamed categories.
Returns
-------
cat : Categorical or None
With ``inplace=False``, the new categorical is returned.
With ``inplace=True``, there is no return value.
Raises
------
ValueError
If new categories are list-like and do not have the same number of
items than the current categories or do not validate as categories
See Also
--------
reorder_categories
add_categories
remove_categories
remove_unused_categories
set_categories
Examples
--------
>>> c = pd.Categorical(['a', 'a', 'b'])
>>> c.rename_categories([0, 1])
[0, 0, 1]
Categories (2, int64): [0, 1]
For dict-like ``new_categories``, extra keys are ignored and
categories not in the dictionary are passed through
>>> c.rename_categories({'a': 'A', 'c': 'C'})
[A, A, b]
Categories (2, object): [A, b]
You may also provide a callable to create the new categories
>>> c.rename_categories(lambda x: x.upper())
[A, A, B]
Categories (2, object): [A, B]
"""
inplace = validate_bool_kwarg(inplace, "inplace")
cat = self if inplace else self.copy()
if is_dict_like(new_categories):
cat.categories = [new_categories.get(item, item) for item in cat.categories]
elif callable(new_categories):
cat.categories = [new_categories(item) for item in cat.categories]
else:
cat.categories = new_categories
if not inplace:
return cat
def reorder_categories(self, new_categories, ordered=None, inplace=False):
"""
Reorder categories as specified in new_categories.
`new_categories` need to include all old categories and no new category
items.
Parameters
----------
new_categories : Index-like
The categories in new order.
ordered : bool, optional
Whether or not the categorical is treated as a ordered categorical.
If not given, do not change the ordered information.
inplace : bool, default False
Whether or not to reorder the categories inplace or return a copy of
this categorical with reordered categories.
Returns
-------
cat : Categorical with reordered categories or None if inplace.
Raises
------
ValueError
If the new categories do not contain all old category items or any
new ones
See Also
--------
rename_categories
add_categories
remove_categories
remove_unused_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if set(self.dtype.categories) != set(new_categories):
raise ValueError(
"items in new_categories are not the same as in old categories"
)
return self.set_categories(new_categories, ordered=ordered, inplace=inplace)
def add_categories(self, new_categories, inplace=False):
"""
Add new categories.
`new_categories` will be included at the last/highest place in the
categories and will be unused directly after this call.
Parameters
----------
new_categories : category or list-like of category
The new categories to be included.
inplace : bool, default False
Whether or not to add the categories inplace or return a copy of
this categorical with added categories.
Returns
-------
cat : Categorical with new categories added or None if inplace.
Raises
------
ValueError
If the new categories include old categories or do not validate as
categories
See Also
--------
rename_categories
reorder_categories
remove_categories
remove_unused_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not is_list_like(new_categories):
new_categories = [new_categories]
already_included = set(new_categories) & set(self.dtype.categories)
if len(already_included) != 0:
msg = (
"new categories must not include old categories: "
"{already_included!s}"
)
raise ValueError(msg.format(already_included=already_included))
new_categories = list(self.dtype.categories) + list(new_categories)
new_dtype = CategoricalDtype(new_categories, self.ordered)
cat = self if inplace else self.copy()
cat._dtype = new_dtype
cat._codes = coerce_indexer_dtype(cat._codes, new_dtype.categories)
if not inplace:
return cat
def remove_categories(self, removals, inplace=False):
"""
Remove the specified categories.
`removals` must be included in the old categories. Values which were in
the removed categories will be set to NaN
Parameters
----------
removals : category or list of categories
The categories which should be removed.
inplace : bool, default False
Whether or not to remove the categories inplace or return a copy of
this categorical with removed categories.
Returns
-------
cat : Categorical with removed categories or None if inplace.
Raises
------
ValueError
If the removals are not contained in the categories
See Also
--------
rename_categories
reorder_categories
add_categories
remove_unused_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not is_list_like(removals):
removals = [removals]
removal_set = set(list(removals))
not_included = removal_set - set(self.dtype.categories)
new_categories = [c for c in self.dtype.categories if c not in removal_set]
# GH 10156
if any(isna(removals)):
not_included = [x for x in not_included if notna(x)]
new_categories = [x for x in new_categories if notna(x)]
if len(not_included) != 0:
msg = "removals must all be in old categories: {not_included!s}"
raise ValueError(msg.format(not_included=not_included))
return self.set_categories(
new_categories, ordered=self.ordered, rename=False, inplace=inplace
)
def remove_unused_categories(self, inplace=False):
"""
Remove categories which are not used.
Parameters
----------
inplace : bool, default False
Whether or not to drop unused categories inplace or return a copy of
this categorical with unused categories dropped.
Returns
-------
cat : Categorical with unused categories dropped or None if inplace.
See Also
--------
rename_categories
reorder_categories
add_categories
remove_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
cat = self if inplace else self.copy()
idx, inv = np.unique(cat._codes, return_inverse=True)
if idx.size != 0 and idx[0] == -1: # na sentinel
idx, inv = idx[1:], inv - 1
new_categories = cat.dtype.categories.take(idx)
new_dtype = CategoricalDtype._from_fastpath(
new_categories, ordered=self.ordered
)
cat._dtype = new_dtype
cat._codes = coerce_indexer_dtype(inv, new_dtype.categories)
if not inplace:
return cat
def map(self, mapper):
"""
Map categories using input correspondence (dict, Series, or function).
Maps the categories to new categories. If the mapping correspondence is
one-to-one the result is a :class:`~pandas.Categorical` which has the
same order property as the original, otherwise a :class:`~pandas.Index`
is returned. NaN values are unaffected.
If a `dict` or :class:`~pandas.Series` is used any unmapped category is
mapped to `NaN`. Note that if this happens an :class:`~pandas.Index`
will be returned.
Parameters
----------
mapper : function, dict, or Series
Mapping correspondence.
Returns
-------
pandas.Categorical or pandas.Index
Mapped categorical.
See Also
--------
CategoricalIndex.map : Apply a mapping correspondence on a
:class:`~pandas.CategoricalIndex`.
Index.map : Apply a mapping correspondence on an
:class:`~pandas.Index`.
Series.map : Apply a mapping correspondence on a
:class:`~pandas.Series`.
Series.apply : Apply more complex functions on a
:class:`~pandas.Series`.
Examples
--------
>>> cat = pd.Categorical(['a', 'b', 'c'])
>>> cat
[a, b, c]
Categories (3, object): [a, b, c]
>>> cat.map(lambda x: x.upper())
[A, B, C]
Categories (3, object): [A, B, C]
>>> cat.map({'a': 'first', 'b': 'second', 'c': 'third'})
[first, second, third]
Categories (3, object): [first, second, third]
If the mapping is one-to-one the ordering of the categories is
preserved:
>>> cat = pd.Categorical(['a', 'b', 'c'], ordered=True)
>>> cat
[a, b, c]
Categories (3, object): [a < b < c]
>>> cat.map({'a': 3, 'b': 2, 'c': 1})
[3, 2, 1]
Categories (3, int64): [3 < 2 < 1]
If the mapping is not one-to-one an :class:`~pandas.Index` is returned:
>>> cat.map({'a': 'first', 'b': 'second', 'c': 'first'})
Index(['first', 'second', 'first'], dtype='object')
If a `dict` is used, all unmapped categories are mapped to `NaN` and
the result is an :class:`~pandas.Index`:
>>> cat.map({'a': 'first', 'b': 'second'})
Index(['first', 'second', nan], dtype='object')
"""
new_categories = self.categories.map(mapper)
try:
return self.from_codes(
self._codes.copy(), categories=new_categories, ordered=self.ordered
)
except ValueError:
# NA values are represented in self._codes with -1
# np.take causes NA values to take final element in new_categories
if np.any(self._codes == -1):
new_categories = new_categories.insert(len(new_categories), np.nan)
return np.take(new_categories, self._codes)
__eq__ = _cat_compare_op(operator.eq)
__ne__ = _cat_compare_op(operator.ne)
__lt__ = _cat_compare_op(operator.lt)
__gt__ = _cat_compare_op(operator.gt)
__le__ = _cat_compare_op(operator.le)
__ge__ = _cat_compare_op(operator.ge)
# for Series/ndarray like compat
@property
def shape(self):
"""
Shape of the Categorical.
For internal compatibility with numpy arrays.
Returns
-------
shape : tuple
"""
return tuple([len(self._codes)])
def shift(self, periods, fill_value=None):
"""
Shift Categorical by desired number of periods.
Parameters
----------
periods : int
Number of periods to move, can be positive or negative
fill_value : object, optional
The scalar value to use for newly introduced missing values.
.. versionadded:: 0.24.0
Returns
-------
shifted : Categorical
"""
# since categoricals always have ndim == 1, an axis parameter
# doesn't make any sense here.
codes = self.codes
if codes.ndim > 1:
raise NotImplementedError("Categorical with ndim > 1.")
if np.prod(codes.shape) and (periods != 0):
codes = np.roll(codes, ensure_platform_int(periods), axis=0)
if isna(fill_value):
fill_value = -1
elif fill_value in self.categories:
fill_value = self.categories.get_loc(fill_value)
else:
raise ValueError(
"'fill_value={}' is not present "
"in this Categorical's "
"categories".format(fill_value)
)
if periods > 0:
codes[:periods] = fill_value
else:
codes[periods:] = fill_value
return self.from_codes(codes, dtype=self.dtype)
def __array__(self, dtype=None):
"""
The numpy array interface.
Returns
-------
numpy.array
A numpy array of either the specified dtype or,
if dtype==None (default), the same dtype as
categorical.categories.dtype.
"""
ret = take_1d(self.categories.values, self._codes)
if dtype and not is_dtype_equal(dtype, self.categories.dtype):
return np.asarray(ret, dtype)
if is_extension_array_dtype(ret):
# When we're a Categorical[ExtensionArray], like Interval,
# we need to ensure __array__ get's all the way to an
# ndarray.
ret = np.asarray(ret)
return ret
def __array_ufunc__(self, ufunc, method, *inputs, **kwargs):
# for binary ops, use our custom dunder methods
result = ops.maybe_dispatch_ufunc_to_dunder_op(
self, ufunc, method, *inputs, **kwargs
)
if result is not NotImplemented:
return result
# for all other cases, raise for now (similarly as what happens in
# Series.__array_prepare__)
raise TypeError(
"Object with dtype {dtype} cannot perform "
"the numpy op {op}".format(dtype=self.dtype, op=ufunc.__name__)
)
def __setstate__(self, state):
"""Necessary for making this object picklable"""
if not isinstance(state, dict):
raise Exception("invalid pickle state")
# compat with pre 0.21.0 CategoricalDtype change
if "_dtype" not in state:
state["_dtype"] = CategoricalDtype(state["_categories"], state["_ordered"])
for k, v in state.items():
setattr(self, k, v)
@property
def T(self):
"""
Return transposed numpy array.
"""
return self
@property
def nbytes(self):
return self._codes.nbytes + self.dtype.categories.values.nbytes
def memory_usage(self, deep=False):
"""
Memory usage of my values
Parameters
----------
deep : bool
Introspect the data deeply, interrogate
`object` dtypes for system-level memory consumption
Returns
-------
bytes used
Notes
-----
Memory usage does not include memory consumed by elements that
are not components of the array if deep=False
See Also
--------
numpy.ndarray.nbytes
"""
return self._codes.nbytes + self.dtype.categories.memory_usage(deep=deep)
@Substitution(klass="Categorical")
@Appender(_shared_docs["searchsorted"])
def searchsorted(self, value, side="left", sorter=None):
# searchsorted is very performance sensitive. By converting codes
# to same dtype as self.codes, we get much faster performance.
if is_scalar(value):
codes = self.categories.get_loc(value)
codes = self.codes.dtype.type(codes)
else:
locs = [self.categories.get_loc(x) for x in value]
codes = np.array(locs, dtype=self.codes.dtype)
return self.codes.searchsorted(codes, side=side, sorter=sorter)
def isna(self):
"""
Detect missing values
Missing values (-1 in .codes) are detected.
Returns
-------
a boolean array of whether my values are null
See Also
--------
isna : Top-level isna.
isnull : Alias of isna.
Categorical.notna : Boolean inverse of Categorical.isna.
"""
ret = self._codes == -1
return ret
isnull = isna
def notna(self):
"""
Inverse of isna
Both missing values (-1 in .codes) and NA as a category are detected as
null.
Returns
-------
a boolean array of whether my values are not null
See Also
--------
notna : Top-level notna.
notnull : Alias of notna.
Categorical.isna : Boolean inverse of Categorical.notna.
"""
return ~self.isna()
notnull = notna
def put(self, *args, **kwargs):
"""
Replace specific elements in the Categorical with given values.
"""
raise NotImplementedError(("'put' is not yet implemented for Categorical"))
def dropna(self):
"""
Return the Categorical without null values.
Missing values (-1 in .codes) are detected.
Returns
-------
valid : Categorical
"""
result = self[self.notna()]
return result
def value_counts(self, dropna=True):
"""
Return a Series containing counts of each category.
Every category will have an entry, even those with a count of 0.
Parameters
----------
dropna : bool, default True
Don't include counts of NaN.
Returns
-------
counts : Series
See Also
--------
Series.value_counts
"""
from pandas import Series, CategoricalIndex
code, cat = self._codes, self.categories
ncat, mask = len(cat), 0 <= code
ix, clean = np.arange(ncat), mask.all()
if dropna or clean:
obs = code if clean else code[mask]
count = np.bincount(obs, minlength=ncat or 0)
else:
count = np.bincount(np.where(mask, code, ncat))
ix = np.append(ix, -1)
ix = self._constructor(ix, dtype=self.dtype, fastpath=True)
return Series(count, index=CategoricalIndex(ix), dtype="int64")
def get_values(self):
"""
Return the values.
.. deprecated:: 0.25.0
For internal compatibility with pandas formatting.
Returns
-------
numpy.array
A numpy array of the same dtype as categorical.categories.dtype or
Index if datetime / periods.
"""
warn(
"The 'get_values' method is deprecated and will be removed in a "
"future version",
FutureWarning,
stacklevel=2,
)
return self._internal_get_values()
def _internal_get_values(self):
# if we are a datetime and period index, return Index to keep metadata
if is_datetimelike(self.categories):
return self.categories.take(self._codes, fill_value=np.nan)
elif is_integer_dtype(self.categories) and -1 in self._codes:
return self.categories.astype("object").take(self._codes, fill_value=np.nan)
return np.array(self)
def check_for_ordered(self, op):
""" assert that we are ordered """
if not self.ordered:
raise TypeError(
"Categorical is not ordered for operation {op}\n"
"you can use .as_ordered() to change the "
"Categorical to an ordered one\n".format(op=op)
)
def _values_for_argsort(self):
return self._codes.copy()
def argsort(self, ascending=True, kind="quicksort", *args, **kwargs):
"""
Return the indices that would sort the Categorical.
.. versionchanged:: 0.25.0
Changed to sort missing values at the end.
Parameters
----------
ascending : bool, default True
Whether the indices should result in an ascending
or descending sort.
kind : {'quicksort', 'mergesort', 'heapsort'}, optional
Sorting algorithm.
*args, **kwargs:
passed through to :func:`numpy.argsort`.
Returns
-------
numpy.array
See Also
--------
numpy.ndarray.argsort
Notes
-----
While an ordering is applied to the category values, arg-sorting
in this context refers more to organizing and grouping together
based on matching category values. Thus, this function can be
called on an unordered Categorical instance unlike the functions
'Categorical.min' and 'Categorical.max'.
Examples
--------
>>> pd.Categorical(['b', 'b', 'a', 'c']).argsort()
array([2, 0, 1, 3])
>>> cat = pd.Categorical(['b', 'b', 'a', 'c'],
... categories=['c', 'b', 'a'],
... ordered=True)
>>> cat.argsort()
array([3, 0, 1, 2])
Missing values are placed at the end
>>> cat = pd.Categorical([2, None, 1])
>>> cat.argsort()
array([2, 0, 1])
"""
return super().argsort(ascending=ascending, kind=kind, *args, **kwargs)
def sort_values(self, inplace=False, ascending=True, na_position="last"):
"""
Sort the Categorical by category value returning a new
Categorical by default.
While an ordering is applied to the category values, sorting in this
context refers more to organizing and grouping together based on
matching category values. Thus, this function can be called on an
unordered Categorical instance unlike the functions 'Categorical.min'
and 'Categorical.max'.
Parameters
----------
inplace : bool, default False
Do operation in place.
ascending : bool, default True
Order ascending. Passing False orders descending. The
ordering parameter provides the method by which the
category values are organized.
na_position : {'first', 'last'} (optional, default='last')
'first' puts NaNs at the beginning
'last' puts NaNs at the end
Returns
-------
Categorical or None
See Also
--------
Categorical.sort
Series.sort_values
Examples
--------
>>> c = pd.Categorical([1, 2, 2, 1, 5])
>>> c
[1, 2, 2, 1, 5]
Categories (3, int64): [1, 2, 5]
>>> c.sort_values()
[1, 1, 2, 2, 5]
Categories (3, int64): [1, 2, 5]
>>> c.sort_values(ascending=False)
[5, 2, 2, 1, 1]
Categories (3, int64): [1, 2, 5]
Inplace sorting can be done as well:
>>> c.sort_values(inplace=True)
>>> c
[1, 1, 2, 2, 5]
Categories (3, int64): [1, 2, 5]
>>>
>>> c = pd.Categorical([1, 2, 2, 1, 5])
'sort_values' behaviour with NaNs. Note that 'na_position'
is independent of the 'ascending' parameter:
>>> c = pd.Categorical([np.nan, 2, 2, np.nan, 5])
>>> c
[NaN, 2.0, 2.0, NaN, 5.0]
Categories (2, int64): [2, 5]
>>> c.sort_values()
[2.0, 2.0, 5.0, NaN, NaN]
Categories (2, int64): [2, 5]
>>> c.sort_values(ascending=False)
[5.0, 2.0, 2.0, NaN, NaN]
Categories (2, int64): [2, 5]
>>> c.sort_values(na_position='first')
[NaN, NaN, 2.0, 2.0, 5.0]
Categories (2, int64): [2, 5]
>>> c.sort_values(ascending=False, na_position='first')
[NaN, NaN, 5.0, 2.0, 2.0]
Categories (2, int64): [2, 5]
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if na_position not in ["last", "first"]:
msg = "invalid na_position: {na_position!r}"
raise ValueError(msg.format(na_position=na_position))
sorted_idx = nargsort(self, ascending=ascending, na_position=na_position)
if inplace:
self._codes = self._codes[sorted_idx]
else:
return self._constructor(
values=self._codes[sorted_idx], dtype=self.dtype, fastpath=True
)
def _values_for_rank(self):
"""
For correctly ranking ordered categorical data. See GH#15420
Ordered categorical data should be ranked on the basis of
codes with -1 translated to NaN.
Returns
-------
numpy.array
"""
from pandas import Series
if self.ordered:
values = self.codes
mask = values == -1
if mask.any():
values = values.astype("float64")
values[mask] = np.nan
elif self.categories.is_numeric():
values = np.array(self)
else:
# reorder the categories (so rank can use the float codes)
# instead of passing an object array to rank
values = np.array(
self.rename_categories(Series(self.categories).rank().values)
)
return values
def ravel(self, order="C"):
"""
Return a flattened (numpy) array.
For internal compatibility with numpy arrays.
Returns
-------
numpy.array
"""
warn(
"Categorical.ravel will return a Categorical object instead "
"of an ndarray in a future version.",
FutureWarning,
stacklevel=2,
)
return np.array(self)
def view(self, dtype=None):
if dtype is not None:
raise NotImplementedError(dtype)
return self._constructor(values=self._codes, dtype=self.dtype, fastpath=True)
def to_dense(self):
"""
Return my 'dense' representation
For internal compatibility with numpy arrays.
Returns
-------
dense : array
"""
return np.asarray(self)
@deprecate_kwarg(old_arg_name="fill_value", new_arg_name="value")
def fillna(self, value=None, method=None, limit=None):
"""
Fill NA/NaN values using the specified method.
Parameters
----------
value : scalar, dict, Series
If a scalar value is passed it is used to fill all missing values.
Alternatively, a Series or dict can be used to fill in different
values for each index. The value should not be a list. The
value(s) passed should either be in the categories or should be
NaN.
method : {'backfill', 'bfill', 'pad', 'ffill', None}, default None
Method to use for filling holes in reindexed Series
pad / ffill: propagate last valid observation forward to next valid
backfill / bfill: use NEXT valid observation to fill gap
limit : int, default None
(Not implemented yet for Categorical!)
If method is specified, this is the maximum number of consecutive
NaN values to forward/backward fill. In other words, if there is
a gap with more than this number of consecutive NaNs, it will only
be partially filled. If method is not specified, this is the
maximum number of entries along the entire axis where NaNs will be
filled.
Returns
-------
filled : Categorical with NA/NaN filled
"""
value, method = validate_fillna_kwargs(
value, method, validate_scalar_dict_value=False
)
if value is None:
value = np.nan
if limit is not None:
raise NotImplementedError(
"specifying a limit for fillna has not been implemented yet"
)
codes = self._codes
# pad / bfill
if method is not None:
values = self.to_dense().reshape(-1, len(self))
values = interpolate_2d(values, method, 0, None, value).astype(
self.categories.dtype
)[0]
codes = _get_codes_for_values(values, self.categories)
else:
# If value is a dict or a Series (a dict value has already
# been converted to a Series)
if isinstance(value, ABCSeries):
if not value[~value.isin(self.categories)].isna().all():
raise ValueError("fill value must be in categories")
values_codes = _get_codes_for_values(value, self.categories)
indexer = np.where(codes == -1)
codes[indexer] = values_codes[indexer]
# If value is not a dict or Series it should be a scalar
elif is_hashable(value):
if not isna(value) and value not in self.categories:
raise ValueError("fill value must be in categories")
mask = codes == -1
if mask.any():
codes = codes.copy()
if isna(value):
codes[mask] = -1
else:
codes[mask] = self.categories.get_loc(value)
else:
raise TypeError(
'"value" parameter must be a scalar, dict '
"or Series, but you passed a "
'"{0}"'.format(type(value).__name__)
)
return self._constructor(codes, dtype=self.dtype, fastpath=True)
def take_nd(self, indexer, allow_fill=None, fill_value=None):
"""
Take elements from the Categorical.
Parameters
----------
indexer : sequence of int
The indices in `self` to take. The meaning of negative values in
`indexer` depends on the value of `allow_fill`.
allow_fill : bool, default None
How to handle negative values in `indexer`.
* False: negative values in `indices` indicate positional indices
from the right. This is similar to
:func:`numpy.take`.
* True: negative values in `indices` indicate missing values
(the default). These values are set to `fill_value`. Any other
other negative values raise a ``ValueError``.
.. versionchanged:: 0.23.0
Deprecated the default value of `allow_fill`. The deprecated
default is ``True``. In the future, this will change to
``False``.
fill_value : object
The value to use for `indices` that are missing (-1), when
``allow_fill=True``. This should be the category, i.e. a value
in ``self.categories``, not a code.
Returns
-------
Categorical
This Categorical will have the same categories and ordered as
`self`.
See Also
--------
Series.take : Similar method for Series.
numpy.ndarray.take : Similar method for NumPy arrays.
Examples
--------
>>> cat = pd.Categorical(['a', 'a', 'b'])
>>> cat
[a, a, b]
Categories (2, object): [a, b]
Specify ``allow_fill==False`` to have negative indices mean indexing
from the right.
>>> cat.take([0, -1, -2], allow_fill=False)
[a, b, a]
Categories (2, object): [a, b]
With ``allow_fill=True``, indices equal to ``-1`` mean "missing"
values that should be filled with the `fill_value`, which is
``np.nan`` by default.
>>> cat.take([0, -1, -1], allow_fill=True)
[a, NaN, NaN]
Categories (2, object): [a, b]
The fill value can be specified.
>>> cat.take([0, -1, -1], allow_fill=True, fill_value='a')
[a, a, a]
Categories (3, object): [a, b]
Specifying a fill value that's not in ``self.categories``
will raise a ``TypeError``.
"""
indexer = np.asarray(indexer, dtype=np.intp)
if allow_fill is None:
if (indexer < 0).any():
warn(_take_msg, FutureWarning, stacklevel=2)
allow_fill = True
dtype = self.dtype
if isna(fill_value):
fill_value = -1
elif allow_fill:
# convert user-provided `fill_value` to codes
if fill_value in self.categories:
fill_value = self.categories.get_loc(fill_value)
else:
msg = "'fill_value' ('{}') is not in this Categorical's categories."
raise TypeError(msg.format(fill_value))
codes = take(self._codes, indexer, allow_fill=allow_fill, fill_value=fill_value)
result = type(self).from_codes(codes, dtype=dtype)
return result
take = take_nd
def __len__(self):
"""
The length of this Categorical.
"""
return len(self._codes)
def __iter__(self):
"""
Returns an Iterator over the values of this Categorical.
"""
return iter(self._internal_get_values().tolist())
def __contains__(self, key):
"""
Returns True if `key` is in this Categorical.
"""
# if key is a NaN, check if any NaN is in self.
if is_scalar(key) and isna(key):
return self.isna().any()
return contains(self, key, container=self._codes)
def _tidy_repr(self, max_vals=10, footer=True):
""" a short repr displaying only max_vals and an optional (but default
footer)
"""
num = max_vals // 2
head = self[:num]._get_repr(length=False, footer=False)
tail = self[-(max_vals - num) :]._get_repr(length=False, footer=False)
result = "{head}, ..., {tail}".format(head=head[:-1], tail=tail[1:])
if footer:
result = "{result}\n{footer}".format(
result=result, footer=self._repr_footer()
)
return str(result)
def _repr_categories(self):
"""
return the base repr for the categories
"""
max_categories = (
10
if get_option("display.max_categories") == 0
else get_option("display.max_categories")
)
from pandas.io.formats import format as fmt
if len(self.categories) > max_categories:
num = max_categories // 2
head = fmt.format_array(self.categories[:num], None)
tail = fmt.format_array(self.categories[-num:], None)
category_strs = head + ["..."] + tail
else:
category_strs = fmt.format_array(self.categories, None)
# Strip all leading spaces, which format_array adds for columns...
category_strs = [x.strip() for x in category_strs]
return category_strs
def _repr_categories_info(self):
"""
Returns a string representation of the footer.
"""
category_strs = self._repr_categories()
dtype = str(self.categories.dtype)
levheader = "Categories ({length}, {dtype}): ".format(
length=len(self.categories), dtype=dtype
)
width, height = get_terminal_size()
max_width = get_option("display.width") or width
if console.in_ipython_frontend():
# 0 = no breaks
max_width = 0
levstring = ""
start = True
cur_col_len = len(levheader) # header
sep_len, sep = (3, " < ") if self.ordered else (2, ", ")
linesep = sep.rstrip() + "\n" # remove whitespace
for val in category_strs:
if max_width != 0 and cur_col_len + sep_len + len(val) > max_width:
levstring += linesep + (" " * (len(levheader) + 1))
cur_col_len = len(levheader) + 1 # header + a whitespace
elif not start:
levstring += sep
cur_col_len += len(val)
levstring += val
start = False
# replace to simple save space by
return levheader + "[" + levstring.replace(" < ... < ", " ... ") + "]"
def _repr_footer(self):
return "Length: {length}\n{info}".format(
length=len(self), info=self._repr_categories_info()
)
def _get_repr(self, length=True, na_rep="NaN", footer=True):
from pandas.io.formats import format as fmt
formatter = fmt.CategoricalFormatter(
self, length=length, na_rep=na_rep, footer=footer
)
result = formatter.to_string()
return str(result)
def __repr__(self):
"""
String representation.
"""
_maxlen = 10
if len(self._codes) > _maxlen:
result = self._tidy_repr(_maxlen)
elif len(self._codes) > 0:
result = self._get_repr(length=len(self) > _maxlen)
else:
msg = self._get_repr(length=False, footer=True).replace("\n", ", ")
result = "[], {repr_msg}".format(repr_msg=msg)
return result
def _maybe_coerce_indexer(self, indexer):
"""
return an indexer coerced to the codes dtype
"""
if isinstance(indexer, np.ndarray) and indexer.dtype.kind == "i":
indexer = indexer.astype(self._codes.dtype)
return indexer
def __getitem__(self, key):
"""
Return an item.
"""
if isinstance(key, (int, np.integer)):
i = self._codes[key]
if i == -1:
return np.nan
else:
return self.categories[i]
else:
return self._constructor(
values=self._codes[key], dtype=self.dtype, fastpath=True
)
def __setitem__(self, key, value):
"""
Item assignment.
Raises
------
ValueError
If (one or more) Value is not in categories or if a assigned
`Categorical` does not have the same categories
"""
value = extract_array(value, extract_numpy=True)
# require identical categories set
if isinstance(value, Categorical):
if not is_dtype_equal(self, value):
raise ValueError(
"Cannot set a Categorical with another, "
"without identical categories"
)
if not self.categories.equals(value.categories):
new_codes = _recode_for_categories(
value.codes, value.categories, self.categories
)
value = Categorical.from_codes(new_codes, dtype=self.dtype)
rvalue = value if is_list_like(value) else [value]
from pandas import Index
to_add = Index(rvalue).difference(self.categories)
# no assignments of values not in categories, but it's always ok to set
# something to np.nan
if len(to_add) and not isna(to_add).all():
raise ValueError(
"Cannot setitem on a Categorical with a new "
"category, set the categories first"
)
# set by position
if isinstance(key, (int, np.integer)):
pass
# tuple of indexers (dataframe)
elif isinstance(key, tuple):
# only allow 1 dimensional slicing, but can
# in a 2-d case be passd (slice(None),....)
if len(key) == 2:
if not com.is_null_slice(key[0]):
raise AssertionError("invalid slicing for a 1-ndim categorical")
key = key[1]
elif len(key) == 1:
key = key[0]
else:
raise AssertionError("invalid slicing for a 1-ndim categorical")
# slicing in Series or Categorical
elif isinstance(key, slice):
pass
# else: array of True/False in Series or Categorical
lindexer = self.categories.get_indexer(rvalue)
lindexer = self._maybe_coerce_indexer(lindexer)
self._codes[key] = lindexer
def _reverse_indexer(self):
"""
Compute the inverse of a categorical, returning
a dict of categories -> indexers.
*This is an internal function*
Returns
-------
dict of categories -> indexers
Examples
--------
>>> c = pd.Categorical(list('aabca'))
>>> c
[a, a, b, c, a]
Categories (3, object): [a, b, c]
>>> c.categories
Index(['a', 'b', 'c'], dtype='object')
>>> c.codes
array([0, 0, 1, 2, 0], dtype=int8)
>>> c._reverse_indexer()
{'a': array([0, 1, 4]), 'b': array([2]), 'c': array([3])}
"""
categories = self.categories
r, counts = libalgos.groupsort_indexer(
self.codes.astype("int64"), categories.size
)
counts = counts.cumsum()
result = (r[start:end] for start, end in zip(counts, counts[1:]))
result = dict(zip(categories, result))
return result
# reduction ops #
def _reduce(self, name, axis=0, **kwargs):
func = getattr(self, name, None)
if func is None:
msg = "Categorical cannot perform the operation {op}"
raise TypeError(msg.format(op=name))
return func(**kwargs)
def min(self, numeric_only=None, **kwargs):
"""
The minimum value of the object.
Only ordered `Categoricals` have a minimum!
Raises
------
TypeError
If the `Categorical` is not `ordered`.
Returns
-------
min : the minimum of this `Categorical`
"""
self.check_for_ordered("min")
if numeric_only:
good = self._codes != -1
pointer = self._codes[good].min(**kwargs)
else:
pointer = self._codes.min(**kwargs)
if pointer == -1:
return np.nan
else:
return self.categories[pointer]
def max(self, numeric_only=None, **kwargs):
"""
The maximum value of the object.
Only ordered `Categoricals` have a maximum!
Raises
------
TypeError
If the `Categorical` is not `ordered`.
Returns
-------
max : the maximum of this `Categorical`
"""
self.check_for_ordered("max")
if numeric_only:
good = self._codes != -1
pointer = self._codes[good].max(**kwargs)
else:
pointer = self._codes.max(**kwargs)
if pointer == -1:
return np.nan
else:
return self.categories[pointer]
def mode(self, dropna=True):
"""
Returns the mode(s) of the Categorical.
Always returns `Categorical` even if only one value.
Parameters
----------
dropna : bool, default True
Don't consider counts of NaN/NaT.
.. versionadded:: 0.24.0
Returns
-------
modes : `Categorical` (sorted)
"""
codes = self._codes
if dropna:
good = self._codes != -1
codes = self._codes[good]
codes = sorted(htable.mode_int64(ensure_int64(codes), dropna))
return self._constructor(values=codes, dtype=self.dtype, fastpath=True)
def unique(self):
"""
Return the ``Categorical`` which ``categories`` and ``codes`` are
unique. Unused categories are NOT returned.
- unordered category: values and categories are sorted by appearance
order.
- ordered category: values are sorted by appearance order, categories
keeps existing order.
Returns
-------
unique values : ``Categorical``
Examples
--------
An unordered Categorical will return categories in the
order of appearance.
>>> pd.Categorical(list('baabc'))
[b, a, c]
Categories (3, object): [b, a, c]
>>> pd.Categorical(list('baabc'), categories=list('abc'))
[b, a, c]
Categories (3, object): [b, a, c]
An ordered Categorical preserves the category ordering.
>>> pd.Categorical(list('baabc'),
... categories=list('abc'),
... ordered=True)
[b, a, c]
Categories (3, object): [a < b < c]
See Also
--------
unique
CategoricalIndex.unique
Series.unique
"""
# unlike np.unique, unique1d does not sort
unique_codes = unique1d(self.codes)
cat = self.copy()
# keep nan in codes
cat._codes = unique_codes
# exclude nan from indexer for categories
take_codes = unique_codes[unique_codes != -1]
if self.ordered:
take_codes = np.sort(take_codes)
return cat.set_categories(cat.categories.take(take_codes))
def _values_for_factorize(self):
codes = self.codes.astype("int64")
return codes, -1
@classmethod
def _from_factorized(cls, uniques, original):
return original._constructor(
original.categories.take(uniques), dtype=original.dtype
)
def equals(self, other):
"""
Returns True if categorical arrays are equal.
Parameters
----------
other : `Categorical`
Returns
-------
bool
"""
if self.is_dtype_equal(other):
if self.categories.equals(other.categories):
# fastpath to avoid re-coding
other_codes = other._codes
else:
other_codes = _recode_for_categories(
other.codes, other.categories, self.categories
)
return np.array_equal(self._codes, other_codes)
return False
def is_dtype_equal(self, other):
"""
Returns True if categoricals are the same dtype
same categories, and same ordered
Parameters
----------
other : Categorical
Returns
-------
bool
"""
try:
return hash(self.dtype) == hash(other.dtype)
except (AttributeError, TypeError):
return False
def describe(self):
"""
Describes this Categorical
Returns
-------
description: `DataFrame`
A dataframe with frequency and counts by category.
"""
counts = self.value_counts(dropna=False)
freqs = counts / float(counts.sum())
from pandas.core.reshape.concat import concat
result = concat([counts, freqs], axis=1)
result.columns = ["counts", "freqs"]
result.index.name = "categories"
return result
@Substitution(klass="Categorical")
@Appender(_extension_array_shared_docs["repeat"])
def repeat(self, repeats, axis=None):
nv.validate_repeat(tuple(), dict(axis=axis))
codes = self._codes.repeat(repeats)
return self._constructor(values=codes, dtype=self.dtype, fastpath=True)
# Implement the ExtensionArray interface
@property
def _can_hold_na(self):
return True
@classmethod
def _concat_same_type(self, to_concat):
from pandas.core.dtypes.concat import concat_categorical
return concat_categorical(to_concat)
def isin(self, values):
"""
Check whether `values` are contained in Categorical.
Return a boolean NumPy Array showing whether each element in
the Categorical matches an element in the passed sequence of
`values` exactly.
Parameters
----------
values : set or list-like
The sequence of values to test. Passing in a single string will
raise a ``TypeError``. Instead, turn a single string into a
list of one element.
Returns
-------
isin : numpy.ndarray (bool dtype)
Raises
------
TypeError
* If `values` is not a set or list-like
See Also
--------
pandas.Series.isin : Equivalent method on Series.
Examples
--------
>>> s = pd.Categorical(['lama', 'cow', 'lama', 'beetle', 'lama',
... 'hippo'])
>>> s.isin(['cow', 'lama'])
array([ True, True, True, False, True, False])
Passing a single string as ``s.isin('lama')`` will raise an error. Use
a list of one element instead:
>>> s.isin(['lama'])
array([ True, False, True, False, True, False])
"""
if not is_list_like(values):
raise TypeError(
"only list-like objects are allowed to be passed"
" to isin(), you passed a [{values_type}]".format(
values_type=type(values).__name__
)
)
values = sanitize_array(values, None, None)
null_mask = np.asarray(isna(values))
code_values = self.categories.get_indexer(values)
code_values = code_values[null_mask | (code_values >= 0)]
return algorithms.isin(self.codes, code_values)
# The Series.cat accessor
@delegate_names(
delegate=Categorical, accessors=["categories", "ordered"], typ="property"
)
@delegate_names(
delegate=Categorical,
accessors=[
"rename_categories",
"reorder_categories",
"add_categories",
"remove_categories",
"remove_unused_categories",
"set_categories",
"as_ordered",
"as_unordered",
],
typ="method",
)
class CategoricalAccessor(PandasDelegate, PandasObject, NoNewAttributesMixin):
"""
Accessor object for categorical properties of the Series values.
Be aware that assigning to `categories` is a inplace operation, while all
methods return new categorical data per default (but can be called with
`inplace=True`).
Parameters
----------
data : Series or CategoricalIndex
Examples
--------
>>> s.cat.categories
>>> s.cat.categories = list('abc')
>>> s.cat.rename_categories(list('cab'))
>>> s.cat.reorder_categories(list('cab'))
>>> s.cat.add_categories(['d','e'])
>>> s.cat.remove_categories(['d'])
>>> s.cat.remove_unused_categories()
>>> s.cat.set_categories(list('abcde'))
>>> s.cat.as_ordered()
>>> s.cat.as_unordered()
"""
def __init__(self, data):
self._validate(data)
self._parent = data.values
self._index = data.index
self._name = data.name
self._freeze()
@staticmethod
def _validate(data):
if not is_categorical_dtype(data.dtype):
raise AttributeError("Can only use .cat accessor with a 'category' dtype")
def _delegate_property_get(self, name):
return getattr(self._parent, name)
def _delegate_property_set(self, name, new_values):
return setattr(self._parent, name, new_values)
@property
def codes(self):
"""
Return Series of codes as well as the index.
"""
from pandas import Series
return Series(self._parent.codes, index=self._index)
def _delegate_method(self, name, *args, **kwargs):
from pandas import Series
method = getattr(self._parent, name)
res = method(*args, **kwargs)
if res is not None:
return Series(res, index=self._index, name=self._name)
@property
def categorical(self):
# Note: Upon deprecation, `test_tab_completion_with_categorical` will
# need to be updated. `categorical` will need to be removed from
# `ok_for_cat`.
warn(
"`Series.cat.categorical` has been deprecated. Use the "
"attributes on 'Series.cat' directly instead.",
FutureWarning,
stacklevel=2,
)
return self._parent
@property
def name(self):
# Note: Upon deprecation, `test_tab_completion_with_categorical` will
# need to be updated. `name` will need to be removed from
# `ok_for_cat`.
warn(
"`Series.cat.name` has been deprecated. Use `Series.name` instead.",
FutureWarning,
stacklevel=2,
)
return self._name
@property
def index(self):
# Note: Upon deprecation, `test_tab_completion_with_categorical` will
# need to be updated. `index` will need to be removed from
# ok_for_cat`.
warn(
"`Series.cat.index` has been deprecated. Use `Series.index` instead.",
FutureWarning,
stacklevel=2,
)
return self._index
# utility routines
def _get_codes_for_values(values, categories):
"""
utility routine to turn values into codes given the specified categories
"""
dtype_equal = is_dtype_equal(values.dtype, categories.dtype)
if dtype_equal:
# To prevent erroneous dtype coercion in _get_data_algo, retrieve
# the underlying numpy array. gh-22702
values = getattr(values, "_ndarray_values", values)
categories = getattr(categories, "_ndarray_values", categories)
elif is_extension_array_dtype(categories.dtype) and is_object_dtype(values):
# Support inferring the correct extension dtype from an array of
# scalar objects. e.g.
# Categorical(array[Period, Period], categories=PeriodIndex(...))
try:
values = categories.dtype.construct_array_type()._from_sequence(values)
except Exception:
# but that may fail for any reason, so fall back to object
values = ensure_object(values)
categories = ensure_object(categories)
else:
values = ensure_object(values)
categories = ensure_object(categories)
(hash_klass, vec_klass), vals = _get_data_algo(values, _hashtables)
(_, _), cats = _get_data_algo(categories, _hashtables)
t = hash_klass(len(cats))
t.map_locations(cats)
return coerce_indexer_dtype(t.lookup(vals), cats)
def _recode_for_categories(codes: np.ndarray, old_categories, new_categories):
"""
Convert a set of codes for to a new set of categories
Parameters
----------
codes : np.ndarray
old_categories, new_categories : Index
Returns
-------
new_codes : np.ndarray[np.int64]
Examples
--------
>>> old_cat = pd.Index(['b', 'a', 'c'])
>>> new_cat = pd.Index(['a', 'b'])
>>> codes = np.array([0, 1, 1, 2])
>>> _recode_for_categories(codes, old_cat, new_cat)
array([ 1, 0, 0, -1])
"""
if len(old_categories) == 0:
# All null anyway, so just retain the nulls
return codes.copy()
elif new_categories.equals(old_categories):
# Same categories, so no need to actually recode
return codes.copy()
indexer = coerce_indexer_dtype(
new_categories.get_indexer(old_categories), new_categories
)
new_codes = take_1d(indexer, codes.copy(), fill_value=-1)
return new_codes
def _convert_to_list_like(list_like):
if hasattr(list_like, "dtype"):
return list_like
if isinstance(list_like, list):
return list_like
if is_sequence(list_like) or isinstance(list_like, tuple) or is_iterator(list_like):
return list(list_like)
elif is_scalar(list_like):
return [list_like]
else:
# TODO: is this reached?
return [list_like]
def _factorize_from_iterable(values):
"""
Factorize an input `values` into `categories` and `codes`. Preserves
categorical dtype in `categories`.
*This is an internal function*
Parameters
----------
values : list-like
Returns
-------
codes : ndarray
categories : Index
If `values` has a categorical dtype, then `categories` is
a CategoricalIndex keeping the categories and order of `values`.
"""
if not is_list_like(values):
raise TypeError("Input must be list-like")
if is_categorical_dtype(values):
values = extract_array(values)
# The Categorical we want to build has the same categories
# as values but its codes are by def [0, ..., len(n_categories) - 1]
cat_codes = np.arange(len(values.categories), dtype=values.codes.dtype)
categories = Categorical.from_codes(cat_codes, dtype=values.dtype)
codes = values.codes
else:
# The value of ordered is irrelevant since we don't use cat as such,
# but only the resulting categories, the order of which is independent
# from ordered. Set ordered to False as default. See GH #15457
cat = Categorical(values, ordered=False)
categories = cat.categories
codes = cat.codes
return codes, categories
def _factorize_from_iterables(iterables):
"""
A higher-level wrapper over `_factorize_from_iterable`.
*This is an internal function*
Parameters
----------
iterables : list-like of list-likes
Returns
-------
codes_list : list of ndarrays
categories_list : list of Indexes
Notes
-----
See `_factorize_from_iterable` for more info.
"""
if len(iterables) == 0:
# For consistency, it should return a list of 2 lists.
return [[], []]
return map(list, zip(*(_factorize_from_iterable(it) for it in iterables)))
import operator
from shutil import get_terminal_size
import textwrap
from typing import Type, Union, cast
from warnings import warn
import numpy as np
from pandas._config import get_option
from pandas._libs import algos as libalgos, hashtable as htable, lib
from pandas.compat.numpy import function as nv
from pandas.util._decorators import (
Appender,
Substitution,
cache_readonly,
deprecate_kwarg,
)
from pandas.util._validators import validate_bool_kwarg, validate_fillna_kwargs
from pandas.core.dtypes.cast import coerce_indexer_dtype, maybe_infer_to_datetimelike
from pandas.core.dtypes.common import (
ensure_int64,
ensure_object,
ensure_platform_int,
is_categorical_dtype,
is_datetime64_dtype,
is_datetimelike,
is_dict_like,
is_dtype_equal,
is_extension_array_dtype,
is_float_dtype,
is_integer_dtype,
is_iterator,
is_list_like,
is_object_dtype,
is_scalar,
is_sequence,
is_timedelta64_dtype,
)
from pandas.core.dtypes.dtypes import CategoricalDtype
from pandas.core.dtypes.generic import ABCDataFrame, ABCIndexClass, ABCSeries
from pandas.core.dtypes.inference import is_hashable
from pandas.core.dtypes.missing import isna, notna
from pandas._typing import ArrayLike, Dtype, Ordered
from pandas.core import ops
from pandas.core.accessor import PandasDelegate, delegate_names
import pandas.core.algorithms as algorithms
from pandas.core.algorithms import (
_get_data_algo,
_hashtables,
factorize,
take,
take_1d,
unique1d,
)
from pandas.core.base import NoNewAttributesMixin, PandasObject, _shared_docs
import pandas.core.common as com
from pandas.core.construction import array, extract_array, sanitize_array
from pandas.core.missing import interpolate_2d
from pandas.core.sorting import nargsort
from pandas.io.formats import console
from .base import ExtensionArray, _extension_array_shared_docs
_take_msg = textwrap.dedent(
"""\
Interpreting negative values in 'indexer' as missing values.
In the future, this will change to meaning positional indices
from the right.
Use 'allow_fill=True' to retain the previous behavior and silence this
warning.
Use 'allow_fill=False' to accept the new behavior."""
)
def _cat_compare_op(op):
opname = "__{op}__".format(op=op.__name__)
def f(self, other):
# On python2, you can usually compare any type to any type, and
# Categoricals can be seen as a custom type, but having different
# results depending whether categories are the same or not is kind of
# insane, so be a bit stricter here and use the python3 idea of
# comparing only things of equal type.
if isinstance(other, (ABCDataFrame, ABCSeries, ABCIndexClass)):
return NotImplemented
other = lib.item_from_zerodim(other)
if is_list_like(other) and len(other) != len(self):
# TODO: Could this fail if the categories are listlike objects?
raise ValueError("Lengths must match.")
if not self.ordered:
if opname in ["__lt__", "__gt__", "__le__", "__ge__"]:
raise TypeError(
"Unordered Categoricals can only compare equality or not"
)
if isinstance(other, Categorical):
# Two Categoricals can only be be compared if the categories are
# the same (maybe up to ordering, depending on ordered)
msg = "Categoricals can only be compared if 'categories' are the same."
if len(self.categories) != len(other.categories):
raise TypeError(msg + " Categories are different lengths")
elif self.ordered and not (self.categories == other.categories).all():
raise TypeError(msg)
elif not set(self.categories) == set(other.categories):
raise TypeError(msg)
if not (self.ordered == other.ordered):
raise TypeError(
"Categoricals can only be compared if 'ordered' is the same"
)
if not self.ordered and not self.categories.equals(other.categories):
# both unordered and different order
other_codes = _get_codes_for_values(other, self.categories)
else:
other_codes = other._codes
mask = (self._codes == -1) | (other_codes == -1)
f = getattr(self._codes, opname)
ret = f(other_codes)
if mask.any():
# In other series, the leads to False, so do that here too
ret[mask] = False
return ret
if is_scalar(other):
if other in self.categories:
i = self.categories.get_loc(other)
ret = getattr(self._codes, opname)(i)
# check for NaN in self
mask = self._codes == -1
ret[mask] = False
return ret
else:
if opname == "__eq__":
return np.repeat(False, len(self))
elif opname == "__ne__":
return np.repeat(True, len(self))
else:
msg = (
"Cannot compare a Categorical for op {op} with a "
"scalar, which is not a category."
)
raise TypeError(msg.format(op=opname))
else:
# allow categorical vs object dtype array comparisons for equality
# these are only positional comparisons
if opname in ["__eq__", "__ne__"]:
return getattr(np.array(self), opname)(np.array(other))
msg = (
"Cannot compare a Categorical for op {op} with type {typ}."
"\nIf you want to compare values, use 'np.asarray(cat) "
"<op> other'."
)
raise TypeError(msg.format(op=opname, typ=type(other)))
f.__name__ = opname
return f
def contains(cat, key, container):
"""
Helper for membership check for ``key`` in ``cat``.
This is a helper method for :method:`__contains__`
and :class:`CategoricalIndex.__contains__`.
Returns True if ``key`` is in ``cat.categories`` and the
location of ``key`` in ``categories`` is in ``container``.
Parameters
----------
cat : :class:`Categorical`or :class:`categoricalIndex`
key : a hashable object
The key to check membership for.
container : Container (e.g. list-like or mapping)
The container to check for membership in.
Returns
-------
is_in : bool
True if ``key`` is in ``self.categories`` and location of
``key`` in ``categories`` is in ``container``, else False.
Notes
-----
This method does not check for NaN values. Do that separately
before calling this method.
"""
hash(key)
# get location of key in categories.
# If a KeyError, the key isn't in categories, so logically
# can't be in container either.
try:
loc = cat.categories.get_loc(key)
except (KeyError, TypeError):
return False
# loc is the location of key in categories, but also the *value*
# for key in container. So, `key` may be in categories,
# but still not in `container`. Example ('b' in categories,
# but not in values):
# 'b' in Categorical(['a'], categories=['a', 'b']) # False
if is_scalar(loc):
return loc in container
else:
# if categories is an IntervalIndex, loc is an array.
return any(loc_ in container for loc_ in loc)
_codes_doc = """
The category codes of this categorical.
Level codes are an array if integer which are the positions of the real
values in the categories array.
There is not setter, use the other categorical methods and the normal item
setter to change values in the categorical.
"""
class Categorical(ExtensionArray, PandasObject):
"""
Represent a categorical variable in classic R / S-plus fashion.
`Categoricals` can only take on only a limited, and usually fixed, number
of possible values (`categories`). In contrast to statistical categorical
variables, a `Categorical` might have an order, but numerical operations
(additions, divisions, ...) are not possible.
All values of the `Categorical` are either in `categories` or `np.nan`.
Assigning values outside of `categories` will raise a `ValueError`. Order
is defined by the order of the `categories`, not lexical order of the
values.
Parameters
----------
values : list-like
The values of the categorical. If categories are given, values not in
categories will be replaced with NaN.
categories : Index-like (unique), optional
The unique categories for this categorical. If not given, the
categories are assumed to be the unique values of `values` (sorted, if
possible, otherwise in the order in which they appear).
ordered : bool, default False
Whether or not this categorical is treated as a ordered categorical.
If True, the resulting categorical will be ordered.
An ordered categorical respects, when sorted, the order of its
`categories` attribute (which in turn is the `categories` argument, if
provided).
dtype : CategoricalDtype
An instance of ``CategoricalDtype`` to use for this categorical
.. versionadded:: 0.21.0
Attributes
----------
categories : Index
The categories of this categorical
codes : ndarray
The codes (integer positions, which point to the categories) of this
categorical, read only.
ordered : bool
Whether or not this Categorical is ordered.
dtype : CategoricalDtype
The instance of ``CategoricalDtype`` storing the ``categories``
and ``ordered``.
.. versionadded:: 0.21.0
Methods
-------
from_codes
__array__
Raises
------
ValueError
If the categories do not validate.
TypeError
If an explicit ``ordered=True`` is given but no `categories` and the
`values` are not sortable.
See Also
--------
api.types.CategoricalDtype : Type for categorical data.
CategoricalIndex : An Index with an underlying ``Categorical``.
Notes
-----
See the `user guide
<http://pandas.pydata.org/pandas-docs/stable/user_guide/categorical.html>`_
for more.
Examples
--------
>>> pd.Categorical([1, 2, 3, 1, 2, 3])
[1, 2, 3, 1, 2, 3]
Categories (3, int64): [1, 2, 3]
>>> pd.Categorical(['a', 'b', 'c', 'a', 'b', 'c'])
[a, b, c, a, b, c]
Categories (3, object): [a, b, c]
Ordered `Categoricals` can be sorted according to the custom order
of the categories and can have a min and max value.
>>> c = pd.Categorical(['a', 'b', 'c', 'a', 'b', 'c'], ordered=True,
... categories=['c', 'b', 'a'])
>>> c
[a, b, c, a, b, c]
Categories (3, object): [c < b < a]
>>> c.min()
'c'
"""
# For comparisons, so that numpy uses our implementation if the compare
# ops, which raise
__array_priority__ = 1000
_dtype = CategoricalDtype(ordered=False)
# tolist is not actually deprecated, just suppressed in the __dir__
_deprecations = frozenset(["labels", "tolist"])
_typ = "categorical"
def __init__(
self, values, categories=None, ordered=None, dtype=None, fastpath=False
):
dtype = CategoricalDtype._from_values_or_dtype(
values, categories, ordered, dtype
)
# At this point, dtype is always a CategoricalDtype, but
# we may have dtype.categories be None, and we need to
# infer categories in a factorization step futher below
if fastpath:
self._codes = coerce_indexer_dtype(values, dtype.categories)
self._dtype = self._dtype.update_dtype(dtype)
return
# null_mask indicates missing values we want to exclude from inference.
# This means: only missing values in list-likes (not arrays/ndframes).
null_mask = np.array(False)
# sanitize input
if is_categorical_dtype(values):
if dtype.categories is None:
dtype = CategoricalDtype(values.categories, dtype._ordered)
elif not isinstance(values, (ABCIndexClass, ABCSeries)):
# sanitize_array coerces np.nan to a string under certain versions
# of numpy
values = maybe_infer_to_datetimelike(values, convert_dates=True)
if not isinstance(values, np.ndarray):
values = _convert_to_list_like(values)
# By convention, empty lists result in object dtype:
if len(values) == 0:
sanitize_dtype = "object"
else:
sanitize_dtype = None
null_mask = isna(values)
if null_mask.any():
values = [values[idx] for idx in np.where(~null_mask)[0]]
values = sanitize_array(values, None, dtype=sanitize_dtype)
if dtype.categories is None:
try:
codes, categories = factorize(values, sort=True)
except TypeError:
codes, categories = factorize(values, sort=False)
if dtype._ordered:
# raise, as we don't have a sortable data structure and so
# the user should give us one by specifying categories
raise TypeError(
"'values' is not ordered, please "
"explicitly specify the categories order "
"by passing in a categories argument."
)
except ValueError:
# FIXME
raise NotImplementedError(
"> 1 ndim Categorical are not supported at this time"
)
# we're inferring from values
dtype = CategoricalDtype(categories, dtype._ordered)
elif is_categorical_dtype(values):
old_codes = (
values._values.codes if isinstance(values, ABCSeries) else values.codes
)
codes = _recode_for_categories(
old_codes, values.dtype.categories, dtype.categories
)
else:
codes = _get_codes_for_values(values, dtype.categories)
if null_mask.any():
# Reinsert -1 placeholders for previously removed missing values
full_codes = -np.ones(null_mask.shape, dtype=codes.dtype)
full_codes[~null_mask] = codes
codes = full_codes
self._dtype = self._dtype.update_dtype(dtype)
self._codes = coerce_indexer_dtype(codes, dtype.categories)
@property
def categories(self):
"""
The categories of this categorical.
Setting assigns new values to each category (effectively a rename of
each individual category).
The assigned value has to be a list-like object. All items must be
unique and the number of items in the new categories must be the same
as the number of items in the old categories.
Assigning to `categories` is a inplace operation!
Raises
------
ValueError
If the new categories do not validate as categories or if the
number of new categories is unequal the number of old categories
See Also
--------
rename_categories
reorder_categories
add_categories
remove_categories
remove_unused_categories
set_categories
"""
return self.dtype.categories
@categories.setter
def categories(self, categories):
new_dtype = CategoricalDtype(categories, ordered=self.ordered)
if self.dtype.categories is not None and len(self.dtype.categories) != len(
new_dtype.categories
):
raise ValueError(
"new categories need to have the same number of "
"items as the old categories!"
)
self._dtype = new_dtype
@property
def ordered(self) -> Ordered:
"""
Whether the categories have an ordered relationship.
"""
return self.dtype._ordered
@property
def dtype(self) -> CategoricalDtype:
"""
The :class:`~pandas.api.types.CategoricalDtype` for this instance.
"""
return self._dtype
@property
def _ndarray_values(self) -> np.ndarray:
return self.codes
@property
def _constructor(self) -> Type["Categorical"]:
return Categorical
@classmethod
def _from_sequence(cls, scalars, dtype=None, copy=False):
return Categorical(scalars, dtype=dtype)
def _formatter(self, boxed=False):
# Defer to CategoricalFormatter's formatter.
return None
def copy(self) -> "Categorical":
"""
Copy constructor.
"""
return self._constructor(
values=self._codes.copy(), dtype=self.dtype, fastpath=True
)
def astype(self, dtype: Dtype, copy: bool = True) -> ArrayLike:
"""
Coerce this type to another dtype
Parameters
----------
dtype : numpy dtype or pandas type
copy : bool, default True
By default, astype always returns a newly allocated object.
If copy is set to False and dtype is categorical, the original
object is returned.
"""
if is_categorical_dtype(dtype):
dtype = cast(Union[str, CategoricalDtype], dtype)
# GH 10696/18593
dtype = self.dtype.update_dtype(dtype)
self = self.copy() if copy else self
if dtype == self.dtype:
return self
return self._set_dtype(dtype)
if is_extension_array_dtype(dtype):
return array(self, dtype=dtype, copy=copy) # type: ignore # GH 28770
if is_integer_dtype(dtype) and self.isna().any():
msg = "Cannot convert float NaN to integer"
raise ValueError(msg)
return np.array(self, dtype=dtype, copy=copy)
@cache_readonly
def size(self) -> int:
"""
return the len of myself
"""
return self._codes.size
@cache_readonly
def itemsize(self) -> int:
"""
return the size of a single category
"""
return self.categories.itemsize
def tolist(self) -> list:
"""
Return a list of the values.
These are each a scalar type, which is a Python scalar
(for str, int, float) or a pandas scalar
(for Timestamp/Timedelta/Interval/Period)
"""
return list(self)
to_list = tolist
@property
def base(self) -> None:
"""
compat, we are always our own object
"""
return None
@classmethod
def _from_inferred_categories(
cls, inferred_categories, inferred_codes, dtype, true_values=None
):
"""
Construct a Categorical from inferred values.
For inferred categories (`dtype` is None) the categories are sorted.
For explicit `dtype`, the `inferred_categories` are cast to the
appropriate type.
Parameters
----------
inferred_categories : Index
inferred_codes : Index
dtype : CategoricalDtype or 'category'
true_values : list, optional
If none are provided, the default ones are
"True", "TRUE", and "true."
Returns
-------
Categorical
"""
from pandas import Index, to_numeric, to_datetime, to_timedelta
cats = Index(inferred_categories)
known_categories = (
isinstance(dtype, CategoricalDtype) and dtype.categories is not None
)
if known_categories:
# Convert to a specialized type with `dtype` if specified.
if dtype.categories.is_numeric():
cats = to_numeric(inferred_categories, errors="coerce")
elif is_datetime64_dtype(dtype.categories):
cats = to_datetime(inferred_categories, errors="coerce")
elif is_timedelta64_dtype(dtype.categories):
cats = to_timedelta(inferred_categories, errors="coerce")
elif dtype.categories.is_boolean():
if true_values is None:
true_values = ["True", "TRUE", "true"]
cats = cats.isin(true_values)
if known_categories:
# Recode from observation order to dtype.categories order.
categories = dtype.categories
codes = _recode_for_categories(inferred_codes, cats, categories)
elif not cats.is_monotonic_increasing:
# Sort categories and recode for unknown categories.
unsorted = cats.copy()
categories = cats.sort_values()
codes = _recode_for_categories(inferred_codes, unsorted, categories)
dtype = CategoricalDtype(categories, ordered=False)
else:
dtype = CategoricalDtype(cats, ordered=False)
codes = inferred_codes
return cls(codes, dtype=dtype, fastpath=True)
@classmethod
def from_codes(cls, codes, categories=None, ordered=None, dtype=None):
"""
Make a Categorical type from codes and categories or dtype.
This constructor is useful if you already have codes and
categories/dtype and so do not need the (computation intensive)
factorization step, which is usually done on the constructor.
If your data does not follow this convention, please use the normal
constructor.
Parameters
----------
codes : array-like, integers
An integer array, where each integer points to a category in
categories or dtype.categories, or else is -1 for NaN.
categories : index-like, optional
The categories for the categorical. Items need to be unique.
If the categories are not given here, then they must be provided
in `dtype`.
ordered : bool, optional
Whether or not this categorical is treated as an ordered
categorical. If not given here or in `dtype`, the resulting
categorical will be unordered.
dtype : CategoricalDtype or the string "category", optional
If :class:`CategoricalDtype`, cannot be used together with
`categories` or `ordered`.
.. versionadded:: 0.24.0
When `dtype` is provided, neither `categories` nor `ordered`
should be provided.
Returns
-------
Categorical
Examples
--------
>>> dtype = pd.CategoricalDtype(['a', 'b'], ordered=True)
>>> pd.Categorical.from_codes(codes=[0, 1, 0, 1], dtype=dtype)
[a, b, a, b]
Categories (2, object): [a < b]
"""
dtype = CategoricalDtype._from_values_or_dtype(
categories=categories, ordered=ordered, dtype=dtype
)
if dtype.categories is None:
msg = (
"The categories must be provided in 'categories' or "
"'dtype'. Both were None."
)
raise ValueError(msg)
codes = np.asarray(codes) # #21767
if not is_integer_dtype(codes):
msg = "codes need to be array-like integers"
if is_float_dtype(codes):
icodes = codes.astype("i8")
if (icodes == codes).all():
msg = None
codes = icodes
warn(
(
"float codes will be disallowed in the future and "
"raise a ValueError"
),
FutureWarning,
stacklevel=2,
)
if msg:
raise ValueError(msg)
if len(codes) and (codes.max() >= len(dtype.categories) or codes.min() < -1):
raise ValueError("codes need to be between -1 and len(categories)-1")
return cls(codes, dtype=dtype, fastpath=True)
def _get_codes(self):
"""
Get the codes.
Returns
-------
codes : integer array view
A non writable view of the `codes` array.
"""
v = self._codes.view()
v.flags.writeable = False
return v
def _set_codes(self, codes):
"""
Not settable by the user directly
"""
raise ValueError("cannot set Categorical codes directly")
codes = property(fget=_get_codes, fset=_set_codes, doc=_codes_doc)
def _set_categories(self, categories, fastpath=False):
"""
Sets new categories inplace
Parameters
----------
fastpath : bool, default False
Don't perform validation of the categories for uniqueness or nulls
Examples
--------
>>> c = pd.Categorical(['a', 'b'])
>>> c
[a, b]
Categories (2, object): [a, b]
>>> c._set_categories(pd.Index(['a', 'c']))
>>> c
[a, c]
Categories (2, object): [a, c]
"""
if fastpath:
new_dtype = CategoricalDtype._from_fastpath(categories, self.ordered)
else:
new_dtype = CategoricalDtype(categories, ordered=self.ordered)
if (
not fastpath
and self.dtype.categories is not None
and len(new_dtype.categories) != len(self.dtype.categories)
):
raise ValueError(
"new categories need to have the same number of "
"items than the old categories!"
)
self._dtype = new_dtype
def _set_dtype(self, dtype: CategoricalDtype) -> "Categorical":
"""
Internal method for directly updating the CategoricalDtype
Parameters
----------
dtype : CategoricalDtype
Notes
-----
We don't do any validation here. It's assumed that the dtype is
a (valid) instance of `CategoricalDtype`.
"""
codes = _recode_for_categories(self.codes, self.categories, dtype.categories)
return type(self)(codes, dtype=dtype, fastpath=True)
def set_ordered(self, value, inplace=False):
"""
Set the ordered attribute to the boolean value.
Parameters
----------
value : bool
Set whether this categorical is ordered (True) or not (False).
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to the value.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
new_dtype = CategoricalDtype(self.categories, ordered=value)
cat = self if inplace else self.copy()
cat._dtype = new_dtype
if not inplace:
return cat
def as_ordered(self, inplace=False):
"""
Set the Categorical to be ordered.
Parameters
----------
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to True.
Returns
-------
Categorical
Ordered Categorical.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
return self.set_ordered(True, inplace=inplace)
def as_unordered(self, inplace=False):
"""
Set the Categorical to be unordered.
Parameters
----------
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to False.
Returns
-------
Categorical
Unordered Categorical.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
return self.set_ordered(False, inplace=inplace)
def set_categories(self, new_categories, ordered=None, rename=False, inplace=False):
"""
Set the categories to the specified new_categories.
`new_categories` can include new categories (which will result in
unused categories) or remove old categories (which results in values
set to NaN). If `rename==True`, the categories will simple be renamed
(less or more items than in old categories will result in values set to
NaN or in unused categories respectively).
This method can be used to perform more than one action of adding,
removing, and reordering simultaneously and is therefore faster than
performing the individual steps via the more specialised methods.
On the other hand this methods does not do checks (e.g., whether the
old categories are included in the new categories on a reorder), which
can result in surprising changes, for example when using special string
dtypes on python3, which does not considers a S1 string equal to a
single char python string.
Parameters
----------
new_categories : Index-like
The categories in new order.
ordered : bool, default False
Whether or not the categorical is treated as a ordered categorical.
If not given, do not change the ordered information.
rename : bool, default False
Whether or not the new_categories should be considered as a rename
of the old categories or as reordered categories.
inplace : bool, default False
Whether or not to reorder the categories in-place or return a copy
of this categorical with reordered categories.
Returns
-------
Categorical with reordered categories or None if inplace.
Raises
------
ValueError
If new_categories does not validate as categories
See Also
--------
rename_categories
reorder_categories
add_categories
remove_categories
remove_unused_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if ordered is None:
ordered = self.dtype._ordered
new_dtype = CategoricalDtype(new_categories, ordered=ordered)
cat = self if inplace else self.copy()
if rename:
if cat.dtype.categories is not None and len(new_dtype.categories) < len(
cat.dtype.categories
):
# remove all _codes which are larger and set to -1/NaN
cat._codes[cat._codes >= len(new_dtype.categories)] = -1
else:
codes = _recode_for_categories(
cat.codes, cat.categories, new_dtype.categories
)
cat._codes = codes
cat._dtype = new_dtype
if not inplace:
return cat
def rename_categories(self, new_categories, inplace=False):
"""
Rename categories.
Parameters
----------
new_categories : list-like, dict-like or callable
* list-like: all items must be unique and the number of items in
the new categories must match the existing number of categories.
* dict-like: specifies a mapping from
old categories to new. Categories not contained in the mapping
are passed through and extra categories in the mapping are
ignored.
.. versionadded:: 0.21.0
* callable : a callable that is called on all items in the old
categories and whose return values comprise the new categories.
.. versionadded:: 0.23.0
inplace : bool, default False
Whether or not to rename the categories inplace or return a copy of
this categorical with renamed categories.
Returns
-------
cat : Categorical or None
With ``inplace=False``, the new categorical is returned.
With ``inplace=True``, there is no return value.
Raises
------
ValueError
If new categories are list-like and do not have the same number of
items than the current categories or do not validate as categories
See Also
--------
reorder_categories
add_categories
remove_categories
remove_unused_categories
set_categories
Examples
--------
>>> c = pd.Categorical(['a', 'a', 'b'])
>>> c.rename_categories([0, 1])
[0, 0, 1]
Categories (2, int64): [0, 1]
For dict-like ``new_categories``, extra keys are ignored and
categories not in the dictionary are passed through
>>> c.rename_categories({'a': 'A', 'c': 'C'})
[A, A, b]
Categories (2, object): [A, b]
You may also provide a callable to create the new categories
>>> c.rename_categories(lambda x: x.upper())
[A, A, B]
Categories (2, object): [A, B]
"""
inplace = validate_bool_kwarg(inplace, "inplace")
cat = self if inplace else self.copy()
if is_dict_like(new_categories):
cat.categories = [new_categories.get(item, item) for item in cat.categories]
elif callable(new_categories):
cat.categories = [new_categories(item) for item in cat.categories]
else:
cat.categories = new_categories
if not inplace:
return cat
def reorder_categories(self, new_categories, ordered=None, inplace=False):
"""
Reorder categories as specified in new_categories.
`new_categories` need to include all old categories and no new category
items.
Parameters
----------
new_categories : Index-like
The categories in new order.
ordered : bool, optional
Whether or not the categorical is treated as a ordered categorical.
If not given, do not change the ordered information.
inplace : bool, default False
Whether or not to reorder the categories inplace or return a copy of
this categorical with reordered categories.
Returns
-------
cat : Categorical with reordered categories or None if inplace.
Raises
------
ValueError
If the new categories do not contain all old category items or any
new ones
See Also
--------
rename_categories
add_categories
remove_categories
remove_unused_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if set(self.dtype.categories) != set(new_categories):
raise ValueError(
"items in new_categories are not the same as in old categories"
)
return self.set_categories(new_categories, ordered=ordered, inplace=inplace)
def add_categories(self, new_categories, inplace=False):
"""
Add new categories.
`new_categories` will be included at the last/highest place in the
categories and will be unused directly after this call.
Parameters
----------
new_categories : category or list-like of category
The new categories to be included.
inplace : bool, default False
Whether or not to add the categories inplace or return a copy of
this categorical with added categories.
Returns
-------
cat : Categorical with new categories added or None if inplace.
Raises
------
ValueError
If the new categories include old categories or do not validate as
categories
See Also
--------
rename_categories
reorder_categories
remove_categories
remove_unused_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not is_list_like(new_categories):
new_categories = [new_categories]
already_included = set(new_categories) & set(self.dtype.categories)
if len(already_included) != 0:
msg = (
"new categories must not include old categories: "
"{already_included!s}"
)
raise ValueError(msg.format(already_included=already_included))
new_categories = list(self.dtype.categories) + list(new_categories)
new_dtype = CategoricalDtype(new_categories, self.ordered)
cat = self if inplace else self.copy()
cat._dtype = new_dtype
cat._codes = coerce_indexer_dtype(cat._codes, new_dtype.categories)
if not inplace:
return cat
def remove_categories(self, removals, inplace=False):
"""
Remove the specified categories.
`removals` must be included in the old categories. Values which were in
the removed categories will be set to NaN
Parameters
----------
removals : category or list of categories
The categories which should be removed.
inplace : bool, default False
Whether or not to remove the categories inplace or return a copy of
this categorical with removed categories.
Returns
-------
cat : Categorical with removed categories or None if inplace.
Raises
------
ValueError
If the removals are not contained in the categories
See Also
--------
rename_categories
reorder_categories
add_categories
remove_unused_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not is_list_like(removals):
removals = [removals]
removal_set = set(list(removals))
not_included = removal_set - set(self.dtype.categories)
new_categories = [c for c in self.dtype.categories if c not in removal_set]
# GH 10156
if any(isna(removals)):
not_included = [x for x in not_included if notna(x)]
new_categories = [x for x in new_categories if notna(x)]
if len(not_included) != 0:
msg = "removals must all be in old categories: {not_included!s}"
raise ValueError(msg.format(not_included=not_included))
return self.set_categories(
new_categories, ordered=self.ordered, rename=False, inplace=inplace
)
def remove_unused_categories(self, inplace=False):
"""
Remove categories which are not used.
Parameters
----------
inplace : bool, default False
Whether or not to drop unused categories inplace or return a copy of
this categorical with unused categories dropped.
Returns
-------
cat : Categorical with unused categories dropped or None if inplace.
See Also
--------
rename_categories
reorder_categories
add_categories
remove_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
cat = self if inplace else self.copy()
idx, inv = np.unique(cat._codes, return_inverse=True)
if idx.size != 0 and idx[0] == -1: # na sentinel
idx, inv = idx[1:], inv - 1
new_categories = cat.dtype.categories.take(idx)
new_dtype = CategoricalDtype._from_fastpath(
new_categories, ordered=self.ordered
)
cat._dtype = new_dtype
cat._codes = coerce_indexer_dtype(inv, new_dtype.categories)
if not inplace:
return cat
def map(self, mapper):
"""
Map categories using input correspondence (dict, Series, or function).
Maps the categories to new categories. If the mapping correspondence is
one-to-one the result is a :class:`~pandas.Categorical` which has the
same order property as the original, otherwise a :class:`~pandas.Index`
is returned. NaN values are unaffected.
If a `dict` or :class:`~pandas.Series` is used any unmapped category is
mapped to `NaN`. Note that if this happens an :class:`~pandas.Index`
will be returned.
Parameters
----------
mapper : function, dict, or Series
Mapping correspondence.
Returns
-------
pandas.Categorical or pandas.Index
Mapped categorical.
See Also
--------
CategoricalIndex.map : Apply a mapping correspondence on a
:class:`~pandas.CategoricalIndex`.
Index.map : Apply a mapping correspondence on an
:class:`~pandas.Index`.
Series.map : Apply a mapping correspondence on a
:class:`~pandas.Series`.
Series.apply : Apply more complex functions on a
:class:`~pandas.Series`.
Examples
--------
>>> cat = pd.Categorical(['a', 'b', 'c'])
>>> cat
[a, b, c]
Categories (3, object): [a, b, c]
>>> cat.map(lambda x: x.upper())
[A, B, C]
Categories (3, object): [A, B, C]
>>> cat.map({'a': 'first', 'b': 'second', 'c': 'third'})
[first, second, third]
Categories (3, object): [first, second, third]
If the mapping is one-to-one the ordering of the categories is
preserved:
>>> cat = pd.Categorical(['a', 'b', 'c'], ordered=True)
>>> cat
[a, b, c]
Categories (3, object): [a < b < c]
>>> cat.map({'a': 3, 'b': 2, 'c': 1})
[3, 2, 1]
Categories (3, int64): [3 < 2 < 1]
If the mapping is not one-to-one an :class:`~pandas.Index` is returned:
>>> cat.map({'a': 'first', 'b': 'second', 'c': 'first'})
Index(['first', 'second', 'first'], dtype='object')
If a `dict` is used, all unmapped categories are mapped to `NaN` and
the result is an :class:`~pandas.Index`:
>>> cat.map({'a': 'first', 'b': 'second'})
Index(['first', 'second', nan], dtype='object')
"""
new_categories = self.categories.map(mapper)
try:
return self.from_codes(
self._codes.copy(), categories=new_categories, ordered=self.ordered
)
except ValueError:
# NA values are represented in self._codes with -1
# np.take causes NA values to take final element in new_categories
if np.any(self._codes == -1):
new_categories = new_categories.insert(len(new_categories), np.nan)
return np.take(new_categories, self._codes)
__eq__ = _cat_compare_op(operator.eq)
__ne__ = _cat_compare_op(operator.ne)
__lt__ = _cat_compare_op(operator.lt)
__gt__ = _cat_compare_op(operator.gt)
__le__ = _cat_compare_op(operator.le)
__ge__ = _cat_compare_op(operator.ge)
# for Series/ndarray like compat
@property
def shape(self):
"""
Shape of the Categorical.
For internal compatibility with numpy arrays.
Returns
-------
shape : tuple
"""
return tuple([len(self._codes)])
def shift(self, periods, fill_value=None):
"""
Shift Categorical by desired number of periods.
Parameters
----------
periods : int
Number of periods to move, can be positive or negative
fill_value : object, optional
The scalar value to use for newly introduced missing values.
.. versionadded:: 0.24.0
Returns
-------
shifted : Categorical
"""
# since categoricals always have ndim == 1, an axis parameter
# doesn't make any sense here.
codes = self.codes
if codes.ndim > 1:
raise NotImplementedError("Categorical with ndim > 1.")
if np.prod(codes.shape) and (periods != 0):
codes = np.roll(codes, ensure_platform_int(periods), axis=0)
if isna(fill_value):
fill_value = -1
elif fill_value in self.categories:
fill_value = self.categories.get_loc(fill_value)
else:
raise ValueError(
"'fill_value={}' is not present "
"in this Categorical's "
"categories".format(fill_value)
)
if periods > 0:
codes[:periods] = fill_value
else:
codes[periods:] = fill_value
return self.from_codes(codes, dtype=self.dtype)
def __array__(self, dtype=None):
"""
The numpy array interface.
Returns
-------
numpy.array
A numpy array of either the specified dtype or,
if dtype==None (default), the same dtype as
categorical.categories.dtype.
"""
ret = take_1d(self.categories.values, self._codes)
if dtype and not is_dtype_equal(dtype, self.categories.dtype):
return np.asarray(ret, dtype)
if is_extension_array_dtype(ret):
# When we're a Categorical[ExtensionArray], like Interval,
# we need to ensure __array__ get's all the way to an
# ndarray.
ret = np.asarray(ret)
return ret
def __array_ufunc__(self, ufunc, method, *inputs, **kwargs):
# for binary ops, use our custom dunder methods
result = ops.maybe_dispatch_ufunc_to_dunder_op(
self, ufunc, method, *inputs, **kwargs
)
if result is not NotImplemented:
return result
# for all other cases, raise for now (similarly as what happens in
# Series.__array_prepare__)
raise TypeError(
"Object with dtype {dtype} cannot perform "
"the numpy op {op}".format(dtype=self.dtype, op=ufunc.__name__)
)
def __setstate__(self, state):
"""Necessary for making this object picklable"""
if not isinstance(state, dict):
raise Exception("invalid pickle state")
# compat with pre 0.21.0 CategoricalDtype change
if "_dtype" not in state:
state["_dtype"] = CategoricalDtype(state["_categories"], state["_ordered"])
for k, v in state.items():
setattr(self, k, v)
@property
def T(self):
"""
Return transposed numpy array.
"""
return self
@property
def nbytes(self):
return self._codes.nbytes + self.dtype.categories.values.nbytes
def memory_usage(self, deep=False):
"""
Memory usage of my values
Parameters
----------
deep : bool
Introspect the data deeply, interrogate
`object` dtypes for system-level memory consumption
Returns
-------
bytes used
Notes
-----
Memory usage does not include memory consumed by elements that
are not components of the array if deep=False
See Also
--------
numpy.ndarray.nbytes
"""
return self._codes.nbytes + self.dtype.categories.memory_usage(deep=deep)
@Substitution(klass="Categorical")
@Appender(_shared_docs["searchsorted"])
def searchsorted(self, value, side="left", sorter=None):
# searchsorted is very performance sensitive. By converting codes
# to same dtype as self.codes, we get much faster performance.
if is_scalar(value):
codes = self.categories.get_loc(value)
codes = self.codes.dtype.type(codes)
else:
locs = [self.categories.get_loc(x) for x in value]
codes = np.array(locs, dtype=self.codes.dtype)
return self.codes.searchsorted(codes, side=side, sorter=sorter)
def isna(self):
"""
Detect missing values
Missing values (-1 in .codes) are detected.
Returns
-------
a boolean array of whether my values are null
See Also
--------
isna : Top-level isna.
isnull : Alias of isna.
Categorical.notna : Boolean inverse of Categorical.isna.
"""
ret = self._codes == -1
return ret
isnull = isna
def notna(self):
"""
Inverse of isna
Both missing values (-1 in .codes) and NA as a category are detected as
null.
Returns
-------
a boolean array of whether my values are not null
See Also
--------
notna : Top-level notna.
notnull : Alias of notna.
Categorical.isna : Boolean inverse of Categorical.notna.
"""
return ~self.isna()
notnull = notna
def put(self, *args, **kwargs):
"""
Replace specific elements in the Categorical with given values.
"""
raise NotImplementedError(("'put' is not yet implemented for Categorical"))
def dropna(self):
"""
Return the Categorical without null values.
Missing values (-1 in .codes) are detected.
Returns
-------
valid : Categorical
"""
result = self[self.notna()]
return result
def value_counts(self, dropna=True):
"""
Return a Series containing counts of each category.
Every category will have an entry, even those with a count of 0.
Parameters
----------
dropna : bool, default True
Don't include counts of NaN.
Returns
-------
counts : Series
See Also
--------
Series.value_counts
"""
from pandas import Series, CategoricalIndex
code, cat = self._codes, self.categories
ncat, mask = len(cat), 0 <= code
ix, clean = np.arange(ncat), mask.all()
if dropna or clean:
obs = code if clean else code[mask]
count = np.bincount(obs, minlength=ncat or 0)
else:
count = np.bincount(np.where(mask, code, ncat))
ix = np.append(ix, -1)
ix = self._constructor(ix, dtype=self.dtype, fastpath=True)
return Series(count, index=CategoricalIndex(ix), dtype="int64")
def get_values(self):
"""
Return the values.
.. deprecated:: 0.25.0
For internal compatibility with pandas formatting.
Returns
-------
numpy.array
A numpy array of the same dtype as categorical.categories.dtype or
Index if datetime / periods.
"""
warn(
"The 'get_values' method is deprecated and will be removed in a "
"future version",
FutureWarning,
stacklevel=2,
)
return self._internal_get_values()
def _internal_get_values(self):
# if we are a datetime and period index, return Index to keep metadata
if is_datetimelike(self.categories):
return self.categories.take(self._codes, fill_value=np.nan)
elif is_integer_dtype(self.categories) and -1 in self._codes:
return self.categories.astype("object").take(self._codes, fill_value=np.nan)
return np.array(self)
def check_for_ordered(self, op):
""" assert that we are ordered """
if not self.ordered:
raise TypeError(
"Categorical is not ordered for operation {op}\n"
"you can use .as_ordered() to change the "
"Categorical to an ordered one\n".format(op=op)
)
def _values_for_argsort(self):
return self._codes.copy()
def argsort(self, ascending=True, kind="quicksort", *args, **kwargs):
"""
Return the indices that would sort the Categorical.
.. versionchanged:: 0.25.0
Changed to sort missing values at the end.
Parameters
----------
ascending : bool, default True
Whether the indices should result in an ascending
or descending sort.
kind : {'quicksort', 'mergesort', 'heapsort'}, optional
Sorting algorithm.
*args, **kwargs:
passed through to :func:`numpy.argsort`.
Returns
-------
numpy.array
See Also
--------
numpy.ndarray.argsort
Notes
-----
While an ordering is applied to the category values, arg-sorting
in this context refers more to organizing and grouping together
based on matching category values. Thus, this function can be
called on an unordered Categorical instance unlike the functions
'Categorical.min' and 'Categorical.max'.
Examples
--------
>>> pd.Categorical(['b', 'b', 'a', 'c']).argsort()
array([2, 0, 1, 3])
>>> cat = pd.Categorical(['b', 'b', 'a', 'c'],
... categories=['c', 'b', 'a'],
... ordered=True)
>>> cat.argsort()
array([3, 0, 1, 2])
Missing values are placed at the end
>>> cat = pd.Categorical([2, None, 1])
>>> cat.argsort()
array([2, 0, 1])
"""
return super().argsort(ascending=ascending, kind=kind, *args, **kwargs)
def sort_values(self, inplace=False, ascending=True, na_position="last"):
"""
Sort the Categorical by category value returning a new
Categorical by default.
While an ordering is applied to the category values, sorting in this
context refers more to organizing and grouping together based on
matching category values. Thus, this function can be called on an
unordered Categorical instance unlike the functions 'Categorical.min'
and 'Categorical.max'.
Parameters
----------
inplace : bool, default False
Do operation in place.
ascending : bool, default True
Order ascending. Passing False orders descending. The
ordering parameter provides the method by which the
category values are organized.
na_position : {'first', 'last'} (optional, default='last')
'first' puts NaNs at the beginning
'last' puts NaNs at the end
Returns
-------
Categorical or None
See Also
--------
Categorical.sort
Series.sort_values
Examples
--------
>>> c = pd.Categorical([1, 2, 2, 1, 5])
>>> c
[1, 2, 2, 1, 5]
Categories (3, int64): [1, 2, 5]
>>> c.sort_values()
[1, 1, 2, 2, 5]
Categories (3, int64): [1, 2, 5]
>>> c.sort_values(ascending=False)
[5, 2, 2, 1, 1]
Categories (3, int64): [1, 2, 5]
Inplace sorting can be done as well:
>>> c.sort_values(inplace=True)
>>> c
[1, 1, 2, 2, 5]
Categories (3, int64): [1, 2, 5]
>>>
>>> c = pd.Categorical([1, 2, 2, 1, 5])
'sort_values' behaviour with NaNs. Note that 'na_position'
is independent of the 'ascending' parameter:
>>> c = pd.Categorical([np.nan, 2, 2, np.nan, 5])
>>> c
[NaN, 2.0, 2.0, NaN, 5.0]
Categories (2, int64): [2, 5]
>>> c.sort_values()
[2.0, 2.0, 5.0, NaN, NaN]
Categories (2, int64): [2, 5]
>>> c.sort_values(ascending=False)
[5.0, 2.0, 2.0, NaN, NaN]
Categories (2, int64): [2, 5]
>>> c.sort_values(na_position='first')
[NaN, NaN, 2.0, 2.0, 5.0]
Categories (2, int64): [2, 5]
>>> c.sort_values(ascending=False, na_position='first')
[NaN, NaN, 5.0, 2.0, 2.0]
Categories (2, int64): [2, 5]
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if na_position not in ["last", "first"]:
msg = "invalid na_position: {na_position!r}"
raise ValueError(msg.format(na_position=na_position))
sorted_idx = nargsort(self, ascending=ascending, na_position=na_position)
if inplace:
self._codes = self._codes[sorted_idx]
else:
return self._constructor(
values=self._codes[sorted_idx], dtype=self.dtype, fastpath=True
)
def _values_for_rank(self):
"""
For correctly ranking ordered categorical data. See GH#15420
Ordered categorical data should be ranked on the basis of
codes with -1 translated to NaN.
Returns
-------
numpy.array
"""
from pandas import Series
if self.ordered:
values = self.codes
mask = values == -1
if mask.any():
values = values.astype("float64")
values[mask] = np.nan
elif self.categories.is_numeric():
values = np.array(self)
else:
# reorder the categories (so rank can use the float codes)
# instead of passing an object array to rank
values = np.array(
self.rename_categories(Series(self.categories).rank().values)
)
return values
def ravel(self, order="C"):
"""
Return a flattened (numpy) array.
For internal compatibility with numpy arrays.
Returns
-------
numpy.array
"""
warn(
"Categorical.ravel will return a Categorical object instead "
"of an ndarray in a future version.",
FutureWarning,
stacklevel=2,
)
return np.array(self)
def view(self, dtype=None):
if dtype is not None:
raise NotImplementedError(dtype)
return self._constructor(values=self._codes, dtype=self.dtype, fastpath=True)
def to_dense(self):
"""
Return my 'dense' representation
For internal compatibility with numpy arrays.
Returns
-------
dense : array
"""
return np.asarray(self)
@deprecate_kwarg(old_arg_name="fill_value", new_arg_name="value")
def fillna(self, value=None, method=None, limit=None):
"""
Fill NA/NaN values using the specified method.
Parameters
----------
value : scalar, dict, Series
If a scalar value is passed it is used to fill all missing values.
Alternatively, a Series or dict can be used to fill in different
values for each index. The value should not be a list. The
value(s) passed should either be in the categories or should be
NaN.
method : {'backfill', 'bfill', 'pad', 'ffill', None}, default None
Method to use for filling holes in reindexed Series
pad / ffill: propagate last valid observation forward to next valid
backfill / bfill: use NEXT valid observation to fill gap
limit : int, default None
(Not implemented yet for Categorical!)
If method is specified, this is the maximum number of consecutive
NaN values to forward/backward fill. In other words, if there is
a gap with more than this number of consecutive NaNs, it will only
be partially filled. If method is not specified, this is the
maximum number of entries along the entire axis where NaNs will be
filled.
Returns
-------
filled : Categorical with NA/NaN filled
"""
value, method = validate_fillna_kwargs(
value, method, validate_scalar_dict_value=False
)
if value is None:
value = np.nan
if limit is not None:
raise NotImplementedError(
"specifying a limit for fillna has not been implemented yet"
)
codes = self._codes
# pad / bfill
if method is not None:
values = self.to_dense().reshape(-1, len(self))
values = interpolate_2d(values, method, 0, None, value).astype(
self.categories.dtype
)[0]
codes = _get_codes_for_values(values, self.categories)
else:
# If value is a dict or a Series (a dict value has already
# been converted to a Series)
if isinstance(value, ABCSeries):
if not value[~value.isin(self.categories)].isna().all():
raise ValueError("fill value must be in categories")
values_codes = _get_codes_for_values(value, self.categories)
indexer = np.where(codes == -1)
codes[indexer] = values_codes[indexer]
# If value is not a dict or Series it should be a scalar
elif is_hashable(value):
if not isna(value) and value not in self.categories:
raise ValueError("fill value must be in categories")
mask = codes == -1
if mask.any():
codes = codes.copy()
if isna(value):
codes[mask] = -1
else:
codes[mask] = self.categories.get_loc(value)
else:
raise TypeError(
'"value" parameter must be a scalar, dict '
"or Series, but you passed a "
'"{0}"'.format(type(value).__name__)
)
return self._constructor(codes, dtype=self.dtype, fastpath=True)
def take_nd(self, indexer, allow_fill=None, fill_value=None):
"""
Take elements from the Categorical.
Parameters
----------
indexer : sequence of int
The indices in `self` to take. The meaning of negative values in
`indexer` depends on the value of `allow_fill`.
allow_fill : bool, default None
How to handle negative values in `indexer`.
* False: negative values in `indices` indicate positional indices
from the right. This is similar to
:func:`numpy.take`.
* True: negative values in `indices` indicate missing values
(the default). These values are set to `fill_value`. Any other
other negative values raise a ``ValueError``.
.. versionchanged:: 0.23.0
Deprecated the default value of `allow_fill`. The deprecated
default is ``True``. In the future, this will change to
``False``.
fill_value : object
The value to use for `indices` that are missing (-1), when
``allow_fill=True``. This should be the category, i.e. a value
in ``self.categories``, not a code.
Returns
-------
Categorical
This Categorical will have the same categories and ordered as
`self`.
See Also
--------
Series.take : Similar method for Series.
numpy.ndarray.take : Similar method for NumPy arrays.
Examples
--------
>>> cat = pd.Categorical(['a', 'a', 'b'])
>>> cat
[a, a, b]
Categories (2, object): [a, b]
Specify ``allow_fill==False`` to have negative indices mean indexing
from the right.
>>> cat.take([0, -1, -2], allow_fill=False)
[a, b, a]
Categories (2, object): [a, b]
With ``allow_fill=True``, indices equal to ``-1`` mean "missing"
values that should be filled with the `fill_value`, which is
``np.nan`` by default.
>>> cat.take([0, -1, -1], allow_fill=True)
[a, NaN, NaN]
Categories (2, object): [a, b]
The fill value can be specified.
>>> cat.take([0, -1, -1], allow_fill=True, fill_value='a')
[a, a, a]
Categories (3, object): [a, b]
Specifying a fill value that's not in ``self.categories``
will raise a ``TypeError``.
"""
indexer = np.asarray(indexer, dtype=np.intp)
if allow_fill is None:
if (indexer < 0).any():
warn(_take_msg, FutureWarning, stacklevel=2)
allow_fill = True
dtype = self.dtype
if isna(fill_value):
fill_value = -1
elif allow_fill:
# convert user-provided `fill_value` to codes
if fill_value in self.categories:
fill_value = self.categories.get_loc(fill_value)
else:
msg = "'fill_value' ('{}') is not in this Categorical's categories."
raise TypeError(msg.format(fill_value))
codes = take(self._codes, indexer, allow_fill=allow_fill, fill_value=fill_value)
result = type(self).from_codes(codes, dtype=dtype)
return result
take = take_nd
def __len__(self):
"""
The length of this Categorical.
"""
return len(self._codes)
def __iter__(self):
"""
Returns an Iterator over the values of this Categorical.
"""
return iter(self._internal_get_values().tolist())
def __contains__(self, key):
"""
Returns True if `key` is in this Categorical.
"""
# if key is a NaN, check if any NaN is in self.
if is_scalar(key) and isna(key):
return self.isna().any()
return contains(self, key, container=self._codes)
def _tidy_repr(self, max_vals=10, footer=True):
""" a short repr displaying only max_vals and an optional (but default
footer)
"""
num = max_vals // 2
head = self[:num]._get_repr(length=False, footer=False)
tail = self[-(max_vals - num) :]._get_repr(length=False, footer=False)
result = "{head}, ..., {tail}".format(head=head[:-1], tail=tail[1:])
if footer:
result = "{result}\n{footer}".format(
result=result, footer=self._repr_footer()
)
return str(result)
def _repr_categories(self):
"""
return the base repr for the categories
"""
max_categories = (
10
if get_option("display.max_categories") == 0
else get_option("display.max_categories")
)
from pandas.io.formats import format as fmt
if len(self.categories) > max_categories:
num = max_categories // 2
head = fmt.format_array(self.categories[:num], None)
tail = fmt.format_array(self.categories[-num:], None)
category_strs = head + ["..."] + tail
else:
category_strs = fmt.format_array(self.categories, None)
# Strip all leading spaces, which format_array adds for columns...
category_strs = [x.strip() for x in category_strs]
return category_strs
def _repr_categories_info(self):
"""
Returns a string representation of the footer.
"""
category_strs = self._repr_categories()
dtype = str(self.categories.dtype)
levheader = "Categories ({length}, {dtype}): ".format(
length=len(self.categories), dtype=dtype
)
width, height = get_terminal_size()
max_width = get_option("display.width") or width
if console.in_ipython_frontend():
# 0 = no breaks
max_width = 0
levstring = ""
start = True
cur_col_len = len(levheader) # header
sep_len, sep = (3, " < ") if self.ordered else (2, ", ")
linesep = sep.rstrip() + "\n" # remove whitespace
for val in category_strs:
if max_width != 0 and cur_col_len + sep_len + len(val) > max_width:
levstring += linesep + (" " * (len(levheader) + 1))
cur_col_len = len(levheader) + 1 # header + a whitespace
elif not start:
levstring += sep
cur_col_len += len(val)
levstring += val
start = False
# replace to simple save space by
return levheader + "[" + levstring.replace(" < ... < ", " ... ") + "]"
def _repr_footer(self):
return "Length: {length}\n{info}".format(
length=len(self), info=self._repr_categories_info()
)
def _get_repr(self, length=True, na_rep="NaN", footer=True):
from pandas.io.formats import format as fmt
formatter = fmt.CategoricalFormatter(
self, length=length, na_rep=na_rep, footer=footer
)
result = formatter.to_string()
return str(result)
def __repr__(self):
"""
String representation.
"""
_maxlen = 10
if len(self._codes) > _maxlen:
result = self._tidy_repr(_maxlen)
elif len(self._codes) > 0:
result = self._get_repr(length=len(self) > _maxlen)
else:
msg = self._get_repr(length=False, footer=True).replace("\n", ", ")
result = "[], {repr_msg}".format(repr_msg=msg)
return result
def _maybe_coerce_indexer(self, indexer):
"""
return an indexer coerced to the codes dtype
"""
if isinstance(indexer, np.ndarray) and indexer.dtype.kind == "i":
indexer = indexer.astype(self._codes.dtype)
return indexer
def __getitem__(self, key):
"""
Return an item.
"""
if isinstance(key, (int, np.integer)):
i = self._codes[key]
if i == -1:
return np.nan
else:
return self.categories[i]
else:
return self._constructor(
values=self._codes[key], dtype=self.dtype, fastpath=True
)
def __setitem__(self, key, value):
"""
Item assignment.
Raises
------
ValueError
If (one or more) Value is not in categories or if a assigned
`Categorical` does not have the same categories
"""
value = extract_array(value, extract_numpy=True)
# require identical categories set
if isinstance(value, Categorical):
if not is_dtype_equal(self, value):
raise ValueError(
"Cannot set a Categorical with another, "
"without identical categories"
)
if not self.categories.equals(value.categories):
new_codes = _recode_for_categories(
value.codes, value.categories, self.categories
)
value = Categorical.from_codes(new_codes, dtype=self.dtype)
rvalue = value if is_list_like(value) else [value]
from pandas import Index
to_add = Index(rvalue).difference(self.categories)
# no assignments of values not in categories, but it's always ok to set
# something to np.nan
if len(to_add) and not isna(to_add).all():
raise ValueError(
"Cannot setitem on a Categorical with a new "
"category, set the categories first"
)
# set by position
if isinstance(key, (int, np.integer)):
pass
# tuple of indexers (dataframe)
elif isinstance(key, tuple):
# only allow 1 dimensional slicing, but can
# in a 2-d case be passd (slice(None),....)
if len(key) == 2:
if not com.is_null_slice(key[0]):
raise AssertionError("invalid slicing for a 1-ndim categorical")
key = key[1]
elif len(key) == 1:
key = key[0]
else:
raise AssertionError("invalid slicing for a 1-ndim categorical")
# slicing in Series or Categorical
elif isinstance(key, slice):
pass
# else: array of True/False in Series or Categorical
lindexer = self.categories.get_indexer(rvalue)
lindexer = self._maybe_coerce_indexer(lindexer)
self._codes[key] = lindexer
def _reverse_indexer(self):
"""
Compute the inverse of a categorical, returning
a dict of categories -> indexers.
*This is an internal function*
Returns
-------
dict of categories -> indexers
Examples
--------
>>> c = pd.Categorical(list('aabca'))
>>> c
[a, a, b, c, a]
Categories (3, object): [a, b, c]
>>> c.categories
Index(['a', 'b', 'c'], dtype='object')
>>> c.codes
array([0, 0, 1, 2, 0], dtype=int8)
>>> c._reverse_indexer()
{'a': array([0, 1, 4]), 'b': array([2]), 'c': array([3])}
"""
categories = self.categories
r, counts = libalgos.groupsort_indexer(
self.codes.astype("int64"), categories.size
)
counts = counts.cumsum()
result = (r[start:end] for start, end in zip(counts, counts[1:]))
result = dict(zip(categories, result))
return result
# reduction ops #
def _reduce(self, name, axis=0, **kwargs):
func = getattr(self, name, None)
if func is None:
msg = "Categorical cannot perform the operation {op}"
raise TypeError(msg.format(op=name))
return func(**kwargs)
def min(self, numeric_only=None, **kwargs):
"""
The minimum value of the object.
Only ordered `Categoricals` have a minimum!
Raises
------
TypeError
If the `Categorical` is not `ordered`.
Returns
-------
min : the minimum of this `Categorical`
"""
self.check_for_ordered("min")
if numeric_only:
good = self._codes != -1
pointer = self._codes[good].min(**kwargs)
else:
pointer = self._codes.min(**kwargs)
if pointer == -1:
return np.nan
else:
return self.categories[pointer]
def max(self, numeric_only=None, **kwargs):
"""
The maximum value of the object.
Only ordered `Categoricals` have a maximum!
Raises
------
TypeError
If the `Categorical` is not `ordered`.
Returns
-------
max : the maximum of this `Categorical`
"""
self.check_for_ordered("max")
if numeric_only:
good = self._codes != -1
pointer = self._codes[good].max(**kwargs)
else:
pointer = self._codes.max(**kwargs)
if pointer == -1:
return np.nan
else:
return self.categories[pointer]
def mode(self, dropna=True):
"""
Returns the mode(s) of the Categorical.
Always returns `Categorical` even if only one value.
Parameters
----------
dropna : bool, default True
Don't consider counts of NaN/NaT.
.. versionadded:: 0.24.0
Returns
-------
modes : `Categorical` (sorted)
"""
codes = self._codes
if dropna:
good = self._codes != -1
codes = self._codes[good]
codes = sorted(htable.mode_int64(ensure_int64(codes), dropna))
return self._constructor(values=codes, dtype=self.dtype, fastpath=True)
def unique(self):
"""
Return the ``Categorical`` which ``categories`` and ``codes`` are
unique. Unused categories are NOT returned.
- unordered category: values and categories are sorted by appearance
order.
- ordered category: values are sorted by appearance order, categories
keeps existing order.
Returns
-------
unique values : ``Categorical``
Examples
--------
An unordered Categorical will return categories in the
order of appearance.
>>> pd.Categorical(list('baabc'))
[b, a, c]
Categories (3, object): [b, a, c]
>>> pd.Categorical(list('baabc'), categories=list('abc'))
[b, a, c]
Categories (3, object): [b, a, c]
An ordered Categorical preserves the category ordering.
>>> pd.Categorical(list('baabc'),
... categories=list('abc'),
... ordered=True)
[b, a, c]
Categories (3, object): [a < b < c]
See Also
--------
unique
CategoricalIndex.unique
Series.unique
"""
# unlike np.unique, unique1d does not sort
unique_codes = unique1d(self.codes)
cat = self.copy()
# keep nan in codes
cat._codes = unique_codes
# exclude nan from indexer for categories
take_codes = unique_codes[unique_codes != -1]
if self.ordered:
take_codes = np.sort(take_codes)
return cat.set_categories(cat.categories.take(take_codes))
def _values_for_factorize(self):
codes = self.codes.astype("int64")
return codes, -1
@classmethod
def _from_factorized(cls, uniques, original):
return original._constructor(
original.categories.take(uniques), dtype=original.dtype
)
def equals(self, other):
"""
Returns True if categorical arrays are equal.
Parameters
----------
other : `Categorical`
Returns
-------
bool
"""
if self.is_dtype_equal(other):
if self.categories.equals(other.categories):
# fastpath to avoid re-coding
other_codes = other._codes
else:
other_codes = _recode_for_categories(
other.codes, other.categories, self.categories
)
return np.array_equal(self._codes, other_codes)
return False
def is_dtype_equal(self, other):
"""
Returns True if categoricals are the same dtype
same categories, and same ordered
Parameters
----------
other : Categorical
Returns
-------
bool
"""
try:
return hash(self.dtype) == hash(other.dtype)
except (AttributeError, TypeError):
return False
def describe(self):
"""
Describes this Categorical
Returns
-------
description: `DataFrame`
A dataframe with frequency and counts by category.
"""
counts = self.value_counts(dropna=False)
freqs = counts / float(counts.sum())
from pandas.core.reshape.concat import concat
result = concat([counts, freqs], axis=1)
result.columns = ["counts", "freqs"]
result.index.name = "categories"
return result
@Substitution(klass="Categorical")
@Appender(_extension_array_shared_docs["repeat"])
def repeat(self, repeats, axis=None):
nv.validate_repeat(tuple(), dict(axis=axis))
codes = self._codes.repeat(repeats)
return self._constructor(values=codes, dtype=self.dtype, fastpath=True)
# Implement the ExtensionArray interface
@property
def _can_hold_na(self):
return True
@classmethod
def _concat_same_type(self, to_concat):
from pandas.core.dtypes.concat import concat_categorical
return concat_categorical(to_concat)
def isin(self, values):
"""
Check whether `values` are contained in Categorical.
Return a boolean NumPy Array showing whether each element in
the Categorical matches an element in the passed sequence of
`values` exactly.
Parameters
----------
values : set or list-like
The sequence of values to test. Passing in a single string will
raise a ``TypeError``. Instead, turn a single string into a
list of one element.
Returns
-------
isin : numpy.ndarray (bool dtype)
Raises
------
TypeError
* If `values` is not a set or list-like
See Also
--------
pandas.Series.isin : Equivalent method on Series.
Examples
--------
>>> s = pd.Categorical(['lama', 'cow', 'lama', 'beetle', 'lama',
... 'hippo'])
>>> s.isin(['cow', 'lama'])
array([ True, True, True, False, True, False])
Passing a single string as ``s.isin('lama')`` will raise an error. Use
a list of one element instead:
>>> s.isin(['lama'])
array([ True, False, True, False, True, False])
"""
if not is_list_like(values):
raise TypeError(
"only list-like objects are allowed to be passed"
" to isin(), you passed a [{values_type}]".format(
values_type=type(values).__name__
)
)
values = sanitize_array(values, None, None)
null_mask = np.asarray(isna(values))
code_values = self.categories.get_indexer(values)
code_values = code_values[null_mask | (code_values >= 0)]
return algorithms.isin(self.codes, code_values)
# The Series.cat accessor
@delegate_names(
delegate=Categorical, accessors=["categories", "ordered"], typ="property"
)
@delegate_names(
delegate=Categorical,
accessors=[
"rename_categories",
"reorder_categories",
"add_categories",
"remove_categories",
"remove_unused_categories",
"set_categories",
"as_ordered",
"as_unordered",
],
typ="method",
)
class CategoricalAccessor(PandasDelegate, PandasObject, NoNewAttributesMixin):
"""
Accessor object for categorical properties of the Series values.
Be aware that assigning to `categories` is a inplace operation, while all
methods return new categorical data per default (but can be called with
`inplace=True`).
Parameters
----------
data : Series or CategoricalIndex
Examples
--------
>>> s.cat.categories
>>> s.cat.categories = list('abc')
>>> s.cat.rename_categories(list('cab'))
>>> s.cat.reorder_categories(list('cab'))
>>> s.cat.add_categories(['d','e'])
>>> s.cat.remove_categories(['d'])
>>> s.cat.remove_unused_categories()
>>> s.cat.set_categories(list('abcde'))
>>> s.cat.as_ordered()
>>> s.cat.as_unordered()
"""
def __init__(self, data):
self._validate(data)
self._parent = data.values
self._index = data.index
self._name = data.name
self._freeze()
@staticmethod
def _validate(data):
if not is_categorical_dtype(data.dtype):
raise AttributeError("Can only use .cat accessor with a 'category' dtype")
def _delegate_property_get(self, name):
return getattr(self._parent, name)
def _delegate_property_set(self, name, new_values):
return setattr(self._parent, name, new_values)
@property
def codes(self):
"""
Return Series of codes as well as the index.
"""
from pandas import Series
return Series(self._parent.codes, index=self._index)
def _delegate_method(self, name, *args, **kwargs):
from pandas import Series
method = getattr(self._parent, name)
res = method(*args, **kwargs)
if res is not None:
return Series(res, index=self._index, name=self._name)
@property
def categorical(self):
# Note: Upon deprecation, `test_tab_completion_with_categorical` will
# need to be updated. `categorical` will need to be removed from
# `ok_for_cat`.
warn(
"`Series.cat.categorical` has been deprecated. Use the "
"attributes on 'Series.cat' directly instead.",
FutureWarning,
stacklevel=2,
)
return self._parent
@property
def name(self):
# Note: Upon deprecation, `test_tab_completion_with_categorical` will
# need to be updated. `name` will need to be removed from
# `ok_for_cat`.
warn(
"`Series.cat.name` has been deprecated. Use `Series.name` instead.",
FutureWarning,
stacklevel=2,
)
return self._name
@property
def index(self):
# Note: Upon deprecation, `test_tab_completion_with_categorical` will
# need to be updated. `index` will need to be removed from
# ok_for_cat`.
warn(
"`Series.cat.index` has been deprecated. Use `Series.index` instead.",
FutureWarning,
stacklevel=2,
)
return self._index
# utility routines
def _get_codes_for_values(values, categories):
"""
utility routine to turn values into codes given the specified categories
"""
dtype_equal = is_dtype_equal(values.dtype, categories.dtype)
if dtype_equal:
# To prevent erroneous dtype coercion in _get_data_algo, retrieve
# the underlying numpy array. gh-22702
values = getattr(values, "_ndarray_values", values)
categories = getattr(categories, "_ndarray_values", categories)
elif is_extension_array_dtype(categories.dtype) and is_object_dtype(values):
# Support inferring the correct extension dtype from an array of
# scalar objects. e.g.
# Categorical(array[Period, Period], categories=PeriodIndex(...))
try:
values = categories.dtype.construct_array_type()._from_sequence(values)
except Exception:
# but that may fail for any reason, so fall back to object
values = ensure_object(values)
categories = ensure_object(categories)
else:
values = ensure_object(values)
categories = ensure_object(categories)
(hash_klass, vec_klass), vals = _get_data_algo(values, _hashtables)
(_, _), cats = _get_data_algo(categories, _hashtables)
t = hash_klass(len(cats))
t.map_locations(cats)
return coerce_indexer_dtype(t.lookup(vals), cats)
def _recode_for_categories(codes: np.ndarray, old_categories, new_categories):
"""
Convert a set of codes for to a new set of categories
Parameters
----------
codes : np.ndarray
old_categories, new_categories : Index
Returns
-------
new_codes : np.ndarray[np.int64]
Examples
--------
>>> old_cat = pd.Index(['b', 'a', 'c'])
>>> new_cat = pd.Index(['a', 'b'])
>>> codes = np.array([0, 1, 1, 2])
>>> _recode_for_categories(codes, old_cat, new_cat)
array([ 1, 0, 0, -1])
"""
if len(old_categories) == 0:
# All null anyway, so just retain the nulls
return codes.copy()
elif new_categories.equals(old_categories):
# Same categories, so no need to actually recode
return codes.copy()
indexer = coerce_indexer_dtype(
new_categories.get_indexer(old_categories), new_categories
)
new_codes = take_1d(indexer, codes.copy(), fill_value=-1)
return new_codes
def _convert_to_list_like(list_like):
if hasattr(list_like, "dtype"):
return list_like
if isinstance(list_like, list):
return list_like
if is_sequence(list_like) or isinstance(list_like, tuple) or is_iterator(list_like):
return list(list_like)
elif is_scalar(list_like):
return [list_like]
else:
# TODO: is this reached?
return [list_like]
def _factorize_from_iterable(values):
"""
Factorize an input `values` into `categories` and `codes`. Preserves
categorical dtype in `categories`.
*This is an internal function*
Parameters
----------
values : list-like
Returns
-------
codes : ndarray
categories : Index
If `values` has a categorical dtype, then `categories` is
a CategoricalIndex keeping the categories and order of `values`.
"""
if not is_list_like(values):
raise TypeError("Input must be list-like")
if is_categorical_dtype(values):
values = extract_array(values)
# The Categorical we want to build has the same categories
# as values but its codes are by def [0, ..., len(n_categories) - 1]
cat_codes = np.arange(len(values.categories), dtype=values.codes.dtype)
categories = Categorical.from_codes(cat_codes, dtype=values.dtype)
codes = values.codes
else:
# The value of ordered is irrelevant since we don't use cat as such,
# but only the resulting categories, the order of which is independent
# from ordered. Set ordered to False as default. See GH #15457
cat = Categorical(values, ordered=False)
categories = cat.categories
codes = cat.codes
return codes, categories
def _factorize_from_iterables(iterables):
"""
A higher-level wrapper over `_factorize_from_iterable`.
*This is an internal function*
Parameters
----------
iterables : list-like of list-likes
Returns
-------
codes_list : list of ndarrays
categories_list : list of Indexes
Notes
-----
See `_factorize_from_iterable` for more info.
"""
if len(iterables) == 0:
# For consistency, it should return a list of 2 lists.
return [[], []]
return map(list, zip(*(_factorize_from_iterable(it) for it in iterables)))
| BugsInPy/BugsInPy/temp/projects/pandas/bug-137-fixed/pandas/pandas/core/arrays/categorical.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-137-buggy/pandas/pandas/core/arrays/categorical.py |
pandas-bug-135 | """
Provide classes to perform the groupby aggregate operations.
These are not exposed to the user and provide implementations of the grouping
operations, primarily in cython. These classes (BaseGrouper and BinGrouper)
are contained *in* the SeriesGroupBy and DataFrameGroupBy objects.
"""
import collections
import numpy as np
from pandas._libs import NaT, iNaT, lib
import pandas._libs.groupby as libgroupby
import pandas._libs.reduction as libreduction
from pandas.errors import AbstractMethodError
from pandas.util._decorators import cache_readonly
from pandas.core.dtypes.common import (
ensure_float64,
ensure_int64,
ensure_int_or_float,
ensure_platform_int,
is_bool_dtype,
is_categorical_dtype,
is_complex_dtype,
is_datetime64_any_dtype,
is_datetime64tz_dtype,
is_integer_dtype,
is_numeric_dtype,
is_sparse,
is_timedelta64_dtype,
needs_i8_conversion,
)
from pandas.core.dtypes.missing import _maybe_fill, isna
import pandas.core.algorithms as algorithms
from pandas.core.base import SelectionMixin
import pandas.core.common as com
from pandas.core.frame import DataFrame
from pandas.core.generic import NDFrame
from pandas.core.groupby import base
from pandas.core.index import Index, MultiIndex, ensure_index
from pandas.core.series import Series
from pandas.core.sorting import (
compress_group_index,
decons_obs_group_ids,
get_flattened_iterator,
get_group_index,
get_group_index_sorter,
get_indexer_dict,
)
def generate_bins_generic(values, binner, closed):
"""
Generate bin edge offsets and bin labels for one array using another array
which has bin edge values. Both arrays must be sorted.
Parameters
----------
values : array of values
binner : a comparable array of values representing bins into which to bin
the first array. Note, 'values' end-points must fall within 'binner'
end-points.
closed : which end of bin is closed; left (default), right
Returns
-------
bins : array of offsets (into 'values' argument) of bins.
Zero and last edge are excluded in result, so for instance the first
bin is values[0:bin[0]] and the last is values[bin[-1]:]
"""
lenidx = len(values)
lenbin = len(binner)
if lenidx <= 0 or lenbin <= 0:
raise ValueError("Invalid length for values or for binner")
# check binner fits data
if values[0] < binner[0]:
raise ValueError("Values falls before first bin")
if values[lenidx - 1] > binner[lenbin - 1]:
raise ValueError("Values falls after last bin")
bins = np.empty(lenbin - 1, dtype=np.int64)
j = 0 # index into values
bc = 0 # bin count
# linear scan, presume nothing about values/binner except that it fits ok
for i in range(0, lenbin - 1):
r_bin = binner[i + 1]
# count values in current bin, advance to next bin
while j < lenidx and (
values[j] < r_bin or (closed == "right" and values[j] == r_bin)
):
j += 1
bins[bc] = j
bc += 1
return bins
class BaseGrouper:
"""
This is an internal Grouper class, which actually holds
the generated groups
Parameters
----------
axis : int
the axis to group
groupings : array of grouping
all the grouping instances to handle in this grouper
for example for grouper list to groupby, need to pass the list
sort : boolean, default True
whether this grouper will give sorted result or not
group_keys : boolean, default True
mutated : boolean, default False
indexer : intp array, optional
the indexer created by Grouper
some groupers (TimeGrouper) will sort its axis and its
group_info is also sorted, so need the indexer to reorder
"""
def __init__(
self, axis, groupings, sort=True, group_keys=True, mutated=False, indexer=None
):
self._filter_empty_groups = self.compressed = len(groupings) != 1
self.axis = axis
self.groupings = groupings
self.sort = sort
self.group_keys = group_keys
self.mutated = mutated
self.indexer = indexer
@property
def shape(self):
return tuple(ping.ngroups for ping in self.groupings)
def __iter__(self):
return iter(self.indices)
@property
def nkeys(self):
return len(self.groupings)
def get_iterator(self, data, axis=0):
"""
Groupby iterator
Returns
-------
Generator yielding sequence of (name, subsetted object)
for each group
"""
splitter = self._get_splitter(data, axis=axis)
keys = self._get_group_keys()
for key, (i, group) in zip(keys, splitter):
yield key, group
def _get_splitter(self, data, axis=0):
comp_ids, _, ngroups = self.group_info
return get_splitter(data, comp_ids, ngroups, axis=axis)
def _get_grouper(self):
"""
We are a grouper as part of another's groupings.
We have a specific method of grouping, so cannot
convert to a Index for our grouper.
"""
return self.groupings[0].grouper
def _get_group_keys(self):
if len(self.groupings) == 1:
return self.levels[0]
else:
comp_ids, _, ngroups = self.group_info
# provide "flattened" iterator for multi-group setting
return get_flattened_iterator(comp_ids, ngroups, self.levels, self.labels)
def apply(self, f, data, axis=0):
mutated = self.mutated
splitter = self._get_splitter(data, axis=axis)
group_keys = self._get_group_keys()
result_values = None
# oh boy
f_name = com.get_callable_name(f)
if (
f_name not in base.plotting_methods
and hasattr(splitter, "fast_apply")
and axis == 0
):
try:
result_values, mutated = splitter.fast_apply(f, group_keys)
# If the fast apply path could be used we can return here.
# Otherwise we need to fall back to the slow implementation.
if len(result_values) == len(group_keys):
return group_keys, result_values, mutated
except libreduction.InvalidApply:
# Cannot fast apply on MultiIndex (_has_complex_internals).
# This Exception is also raised if `f` triggers an exception
# but it is preferable to raise the exception in Python.
pass
except TypeError as err:
if "Cannot convert" in str(err):
# via apply_frame_axis0 if we pass a non-ndarray
pass
else:
raise
for key, (i, group) in zip(group_keys, splitter):
object.__setattr__(group, "name", key)
# result_values is None if fast apply path wasn't taken
# or fast apply aborted with an unexpected exception.
# In either case, initialize the result list and perform
# the slow iteration.
if result_values is None:
result_values = []
# If result_values is not None we're in the case that the
# fast apply loop was broken prematurely but we have
# already the result for the first group which we can reuse.
elif i == 0:
continue
# group might be modified
group_axes = _get_axes(group)
res = f(group)
if not _is_indexed_like(res, group_axes):
mutated = True
result_values.append(res)
return group_keys, result_values, mutated
@cache_readonly
def indices(self):
""" dict {group name -> group indices} """
if len(self.groupings) == 1:
return self.groupings[0].indices
else:
label_list = [ping.labels for ping in self.groupings]
keys = [com.values_from_object(ping.group_index) for ping in self.groupings]
return get_indexer_dict(label_list, keys)
@property
def labels(self):
return [ping.labels for ping in self.groupings]
@property
def levels(self):
return [ping.group_index for ping in self.groupings]
@property
def names(self):
return [ping.name for ping in self.groupings]
def size(self):
"""
Compute group sizes
"""
ids, _, ngroup = self.group_info
ids = ensure_platform_int(ids)
if ngroup:
out = np.bincount(ids[ids != -1], minlength=ngroup)
else:
out = []
return Series(out, index=self.result_index, dtype="int64")
@cache_readonly
def groups(self):
""" dict {group name -> group labels} """
if len(self.groupings) == 1:
return self.groupings[0].groups
else:
to_groupby = zip(*(ping.grouper for ping in self.groupings))
to_groupby = Index(to_groupby)
return self.axis.groupby(to_groupby)
@cache_readonly
def is_monotonic(self):
# return if my group orderings are monotonic
return Index(self.group_info[0]).is_monotonic
@cache_readonly
def group_info(self):
comp_ids, obs_group_ids = self._get_compressed_labels()
ngroups = len(obs_group_ids)
comp_ids = ensure_int64(comp_ids)
return comp_ids, obs_group_ids, ngroups
@cache_readonly
def label_info(self):
# return the labels of items in original grouped axis
labels, _, _ = self.group_info
if self.indexer is not None:
sorter = np.lexsort((labels, self.indexer))
labels = labels[sorter]
return labels
def _get_compressed_labels(self):
all_labels = [ping.labels for ping in self.groupings]
if len(all_labels) > 1:
group_index = get_group_index(all_labels, self.shape, sort=True, xnull=True)
return compress_group_index(group_index, sort=self.sort)
ping = self.groupings[0]
return ping.labels, np.arange(len(ping.group_index))
@cache_readonly
def ngroups(self):
return len(self.result_index)
@property
def recons_labels(self):
comp_ids, obs_ids, _ = self.group_info
labels = (ping.labels for ping in self.groupings)
return decons_obs_group_ids(comp_ids, obs_ids, self.shape, labels, xnull=True)
@cache_readonly
def result_index(self):
if not self.compressed and len(self.groupings) == 1:
return self.groupings[0].result_index.rename(self.names[0])
codes = self.recons_labels
levels = [ping.result_index for ping in self.groupings]
result = MultiIndex(
levels=levels, codes=codes, verify_integrity=False, names=self.names
)
return result
def get_group_levels(self):
if not self.compressed and len(self.groupings) == 1:
return [self.groupings[0].result_index]
name_list = []
for ping, labels in zip(self.groupings, self.recons_labels):
labels = ensure_platform_int(labels)
levels = ping.result_index.take(labels)
name_list.append(levels)
return name_list
# ------------------------------------------------------------
# Aggregation functions
_cython_functions = {
"aggregate": {
"add": "group_add",
"prod": "group_prod",
"min": "group_min",
"max": "group_max",
"mean": "group_mean",
"median": {"name": "group_median"},
"var": "group_var",
"first": {
"name": "group_nth",
"f": lambda func, a, b, c, d, e: func(a, b, c, d, 1, -1),
},
"last": "group_last",
"ohlc": "group_ohlc",
},
"transform": {
"cumprod": "group_cumprod",
"cumsum": "group_cumsum",
"cummin": "group_cummin",
"cummax": "group_cummax",
"rank": {
"name": "group_rank",
"f": lambda func, a, b, c, d, e, **kwargs: func(
a,
b,
c,
e,
kwargs.get("ties_method", "average"),
kwargs.get("ascending", True),
kwargs.get("pct", False),
kwargs.get("na_option", "keep"),
),
},
},
}
_cython_arity = {"ohlc": 4} # OHLC
_name_functions = {"ohlc": lambda *args: ["open", "high", "low", "close"]}
def _is_builtin_func(self, arg):
"""
if we define an builtin function for this argument, return it,
otherwise return the arg
"""
return SelectionMixin._builtin_table.get(arg, arg)
def _get_cython_function(self, kind, how, values, is_numeric):
dtype_str = values.dtype.name
def get_func(fname):
# see if there is a fused-type version of function
# only valid for numeric
f = getattr(libgroupby, fname, None)
if f is not None and is_numeric:
return f
# otherwise find dtype-specific version, falling back to object
for dt in [dtype_str, "object"]:
f2 = getattr(
libgroupby,
"{fname}_{dtype_str}".format(fname=fname, dtype_str=dt),
None,
)
if f2 is not None:
return f2
if hasattr(f, "__signatures__"):
# inspect what fused types are implemented
if dtype_str == "object" and "object" not in f.__signatures__:
# return None so we get a NotImplementedError below
# instead of a TypeError at runtime
return None
return f
ftype = self._cython_functions[kind][how]
if isinstance(ftype, dict):
func = afunc = get_func(ftype["name"])
# a sub-function
f = ftype.get("f")
if f is not None:
def wrapper(*args, **kwargs):
return f(afunc, *args, **kwargs)
# need to curry our sub-function
func = wrapper
else:
func = get_func(ftype)
if func is None:
raise NotImplementedError(
"function is not implemented for this dtype: "
"[how->{how},dtype->{dtype_str}]".format(how=how, dtype_str=dtype_str)
)
return func
def _cython_operation(self, kind, values, how, axis, min_count=-1, **kwargs):
assert kind in ["transform", "aggregate"]
orig_values = values
# can we do this operation with our cython functions
# if not raise NotImplementedError
# we raise NotImplemented if this is an invalid operation
# entirely, e.g. adding datetimes
# categoricals are only 1d, so we
# are not setup for dim transforming
if is_categorical_dtype(values) or is_sparse(values):
raise NotImplementedError("{} dtype not supported".format(values.dtype))
elif is_datetime64_any_dtype(values):
if how in ["add", "prod", "cumsum", "cumprod"]:
raise NotImplementedError(
"datetime64 type does not support {} operations".format(how)
)
elif is_timedelta64_dtype(values):
if how in ["prod", "cumprod"]:
raise NotImplementedError(
"timedelta64 type does not support {} operations".format(how)
)
if is_datetime64tz_dtype(values.dtype):
# Cast to naive; we'll cast back at the end of the function
# TODO: possible need to reshape? kludge can be avoided when
# 2D EA is allowed.
values = values.view("M8[ns]")
is_datetimelike = needs_i8_conversion(values.dtype)
is_numeric = is_numeric_dtype(values.dtype)
if is_datetimelike:
values = values.view("int64")
is_numeric = True
elif is_bool_dtype(values.dtype):
values = ensure_float64(values)
elif is_integer_dtype(values):
# we use iNaT for the missing value on ints
# so pre-convert to guard this condition
if (values == iNaT).any():
values = ensure_float64(values)
else:
values = ensure_int_or_float(values)
elif is_numeric and not is_complex_dtype(values):
values = ensure_float64(values)
else:
values = values.astype(object)
arity = self._cython_arity.get(how, 1)
vdim = values.ndim
swapped = False
if vdim == 1:
values = values[:, None]
out_shape = (self.ngroups, arity)
else:
if axis > 0:
swapped = True
assert axis == 1, axis
values = values.T
if arity > 1:
raise NotImplementedError(
"arity of more than 1 is not supported for the 'how' argument"
)
out_shape = (self.ngroups,) + values.shape[1:]
try:
func = self._get_cython_function(kind, how, values, is_numeric)
except NotImplementedError:
if is_numeric:
try:
values = ensure_float64(values)
except TypeError:
if lib.infer_dtype(values, skipna=False) == "complex":
values = values.astype(complex)
else:
raise
func = self._get_cython_function(kind, how, values, is_numeric)
else:
raise
if how == "rank":
out_dtype = "float"
else:
if is_numeric:
out_dtype = "{kind}{itemsize}".format(
kind=values.dtype.kind, itemsize=values.dtype.itemsize
)
else:
out_dtype = "object"
labels, _, _ = self.group_info
if kind == "aggregate":
result = _maybe_fill(
np.empty(out_shape, dtype=out_dtype), fill_value=np.nan
)
counts = np.zeros(self.ngroups, dtype=np.int64)
result = self._aggregate(
result,
counts,
values,
labels,
func,
is_numeric,
is_datetimelike,
min_count,
)
elif kind == "transform":
result = _maybe_fill(
np.empty_like(values, dtype=out_dtype), fill_value=np.nan
)
# TODO: min_count
result = self._transform(
result, values, labels, func, is_numeric, is_datetimelike, **kwargs
)
if is_integer_dtype(result) and not is_datetimelike:
mask = result == iNaT
if mask.any():
result = result.astype("float64")
result[mask] = np.nan
if kind == "aggregate" and self._filter_empty_groups and not counts.all():
assert result.ndim != 2
result = result[counts > 0]
if vdim == 1 and arity == 1:
result = result[:, 0]
if how in self._name_functions:
# TODO
names = self._name_functions[how]()
else:
names = None
if swapped:
result = result.swapaxes(0, axis)
if is_datetime64tz_dtype(orig_values.dtype):
result = type(orig_values)(result.astype(np.int64), dtype=orig_values.dtype)
elif is_datetimelike and kind == "aggregate":
result = result.astype(orig_values.dtype)
return result, names
def aggregate(self, values, how, axis=0, min_count=-1):
return self._cython_operation(
"aggregate", values, how, axis, min_count=min_count
)
def transform(self, values, how, axis=0, **kwargs):
return self._cython_operation("transform", values, how, axis, **kwargs)
def _aggregate(
self,
result,
counts,
values,
comp_ids,
agg_func,
is_numeric,
is_datetimelike,
min_count=-1,
):
if values.ndim > 2:
# punting for now
raise NotImplementedError("number of dimensions is currently limited to 2")
else:
agg_func(result, counts, values, comp_ids, min_count)
return result
def _transform(
self,
result,
values,
comp_ids,
transform_func,
is_numeric,
is_datetimelike,
**kwargs
):
comp_ids, _, ngroups = self.group_info
if values.ndim > 2:
# punting for now
raise NotImplementedError("number of dimensions is currently limited to 2")
else:
transform_func(result, values, comp_ids, ngroups, is_datetimelike, **kwargs)
return result
def agg_series(self, obj, func):
try:
return self._aggregate_series_fast(obj, func)
except AssertionError:
raise
except ValueError as err:
if "No result." in str(err):
# raised in libreduction
pass
elif "Function does not reduce" in str(err):
# raised in libreduction
pass
else:
raise
return self._aggregate_series_pure_python(obj, func)
def _aggregate_series_fast(self, obj, func):
func = self._is_builtin_func(func)
if obj.index._has_complex_internals:
raise TypeError("Incompatible index for Cython grouper")
group_index, _, ngroups = self.group_info
# avoids object / Series creation overhead
dummy = obj._get_values(slice(None, 0))
indexer = get_group_index_sorter(group_index, ngroups)
obj = obj.take(indexer)
group_index = algorithms.take_nd(group_index, indexer, allow_fill=False)
grouper = libreduction.SeriesGrouper(obj, func, group_index, ngroups, dummy)
result, counts = grouper.get_result()
return result, counts
def _aggregate_series_pure_python(self, obj, func):
group_index, _, ngroups = self.group_info
counts = np.zeros(ngroups, dtype=int)
result = None
splitter = get_splitter(obj, group_index, ngroups, axis=self.axis)
for label, group in splitter:
res = func(group)
if result is None:
if isinstance(res, (Series, Index, np.ndarray)):
raise ValueError("Function does not reduce")
result = np.empty(ngroups, dtype="O")
counts[label] = group.shape[0]
result[label] = res
result = lib.maybe_convert_objects(result, try_float=0)
return result, counts
class BinGrouper(BaseGrouper):
"""
This is an internal Grouper class
Parameters
----------
bins : the split index of binlabels to group the item of axis
binlabels : the label list
filter_empty : boolean, default False
mutated : boolean, default False
indexer : a intp array
Examples
--------
bins: [2, 4, 6, 8, 10]
binlabels: DatetimeIndex(['2005-01-01', '2005-01-03',
'2005-01-05', '2005-01-07', '2005-01-09'],
dtype='datetime64[ns]', freq='2D')
the group_info, which contains the label of each item in grouped
axis, the index of label in label list, group number, is
(array([0, 0, 1, 1, 2, 2, 3, 3, 4, 4]), array([0, 1, 2, 3, 4]), 5)
means that, the grouped axis has 10 items, can be grouped into 5
labels, the first and second items belong to the first label, the
third and forth items belong to the second label, and so on
"""
def __init__(
self, bins, binlabels, filter_empty=False, mutated=False, indexer=None
):
self.bins = ensure_int64(bins)
self.binlabels = ensure_index(binlabels)
self._filter_empty_groups = filter_empty
self.mutated = mutated
self.indexer = indexer
@cache_readonly
def groups(self):
""" dict {group name -> group labels} """
# this is mainly for compat
# GH 3881
result = {
key: value
for key, value in zip(self.binlabels, self.bins)
if key is not NaT
}
return result
@property
def nkeys(self):
return 1
def _get_grouper(self):
"""
We are a grouper as part of another's groupings.
We have a specific method of grouping, so cannot
convert to a Index for our grouper.
"""
return self
def get_iterator(self, data, axis=0):
"""
Groupby iterator
Returns
-------
Generator yielding sequence of (name, subsetted object)
for each group
"""
if isinstance(data, NDFrame):
slicer = lambda start, edge: data._slice(slice(start, edge), axis=axis)
length = len(data.axes[axis])
else:
slicer = lambda start, edge: data[slice(start, edge)]
length = len(data)
start = 0
for edge, label in zip(self.bins, self.binlabels):
if label is not NaT:
yield label, slicer(start, edge)
start = edge
if start < length:
yield self.binlabels[-1], slicer(start, None)
@cache_readonly
def indices(self):
indices = collections.defaultdict(list)
i = 0
for label, bin in zip(self.binlabels, self.bins):
if i < bin:
if label is not NaT:
indices[label] = list(range(i, bin))
i = bin
return indices
@cache_readonly
def group_info(self):
ngroups = self.ngroups
obs_group_ids = np.arange(ngroups)
rep = np.diff(np.r_[0, self.bins])
rep = ensure_platform_int(rep)
if ngroups == len(self.bins):
comp_ids = np.repeat(np.arange(ngroups), rep)
else:
comp_ids = np.repeat(np.r_[-1, np.arange(ngroups)], rep)
return (
comp_ids.astype("int64", copy=False),
obs_group_ids.astype("int64", copy=False),
ngroups,
)
@cache_readonly
def result_index(self):
if len(self.binlabels) != 0 and isna(self.binlabels[0]):
return self.binlabels[1:]
return self.binlabels
@property
def levels(self):
return [self.binlabels]
@property
def names(self):
return [self.binlabels.name]
@property
def groupings(self):
from pandas.core.groupby.grouper import Grouping
return [
Grouping(lvl, lvl, in_axis=False, level=None, name=name)
for lvl, name in zip(self.levels, self.names)
]
def agg_series(self, obj, func):
dummy = obj[:0]
grouper = libreduction.SeriesBinGrouper(obj, func, self.bins, dummy)
return grouper.get_result()
def _get_axes(group):
if isinstance(group, Series):
return [group.index]
else:
return group.axes
def _is_indexed_like(obj, axes):
if isinstance(obj, Series):
if len(axes) > 1:
return False
return obj.index.equals(axes[0])
elif isinstance(obj, DataFrame):
return obj.index.equals(axes[0])
return False
# ----------------------------------------------------------------------
# Splitting / application
class DataSplitter:
def __init__(self, data, labels, ngroups, axis=0):
self.data = data
self.labels = ensure_int64(labels)
self.ngroups = ngroups
self.axis = axis
@cache_readonly
def slabels(self):
# Sorted labels
return algorithms.take_nd(self.labels, self.sort_idx, allow_fill=False)
@cache_readonly
def sort_idx(self):
# Counting sort indexer
return get_group_index_sorter(self.labels, self.ngroups)
def __iter__(self):
sdata = self._get_sorted_data()
if self.ngroups == 0:
# we are inside a generator, rather than raise StopIteration
# we merely return signal the end
return
starts, ends = lib.generate_slices(self.slabels, self.ngroups)
for i, (start, end) in enumerate(zip(starts, ends)):
# Since I'm now compressing the group ids, it's now not "possible"
# to produce empty slices because such groups would not be observed
# in the data
# if start >= end:
# raise AssertionError('Start %s must be less than end %s'
# % (str(start), str(end)))
yield i, self._chop(sdata, slice(start, end))
def _get_sorted_data(self):
return self.data.take(self.sort_idx, axis=self.axis)
def _chop(self, sdata, slice_obj):
raise AbstractMethodError(self)
def apply(self, f):
raise AbstractMethodError(self)
class SeriesSplitter(DataSplitter):
def _chop(self, sdata, slice_obj):
return sdata._get_values(slice_obj)
class FrameSplitter(DataSplitter):
def fast_apply(self, f, names):
# must return keys::list, values::list, mutated::bool
starts, ends = lib.generate_slices(self.slabels, self.ngroups)
sdata = self._get_sorted_data()
return libreduction.apply_frame_axis0(sdata, f, names, starts, ends)
def _chop(self, sdata, slice_obj):
if self.axis == 0:
return sdata.iloc[slice_obj]
else:
return sdata._slice(slice_obj, axis=1)
def get_splitter(data, *args, **kwargs):
if isinstance(data, Series):
klass = SeriesSplitter
elif isinstance(data, DataFrame):
klass = FrameSplitter
return klass(data, *args, **kwargs)
"""
Provide classes to perform the groupby aggregate operations.
These are not exposed to the user and provide implementations of the grouping
operations, primarily in cython. These classes (BaseGrouper and BinGrouper)
are contained *in* the SeriesGroupBy and DataFrameGroupBy objects.
"""
import collections
import numpy as np
from pandas._libs import NaT, iNaT, lib
import pandas._libs.groupby as libgroupby
import pandas._libs.reduction as libreduction
from pandas.errors import AbstractMethodError
from pandas.util._decorators import cache_readonly
from pandas.core.dtypes.common import (
ensure_float64,
ensure_int64,
ensure_int_or_float,
ensure_platform_int,
is_bool_dtype,
is_categorical_dtype,
is_complex_dtype,
is_datetime64_any_dtype,
is_datetime64tz_dtype,
is_integer_dtype,
is_numeric_dtype,
is_sparse,
is_timedelta64_dtype,
needs_i8_conversion,
)
from pandas.core.dtypes.missing import _maybe_fill, isna
import pandas.core.algorithms as algorithms
from pandas.core.base import SelectionMixin
import pandas.core.common as com
from pandas.core.frame import DataFrame
from pandas.core.generic import NDFrame
from pandas.core.groupby import base
from pandas.core.index import Index, MultiIndex, ensure_index
from pandas.core.series import Series
from pandas.core.sorting import (
compress_group_index,
decons_obs_group_ids,
get_flattened_iterator,
get_group_index,
get_group_index_sorter,
get_indexer_dict,
)
def generate_bins_generic(values, binner, closed):
"""
Generate bin edge offsets and bin labels for one array using another array
which has bin edge values. Both arrays must be sorted.
Parameters
----------
values : array of values
binner : a comparable array of values representing bins into which to bin
the first array. Note, 'values' end-points must fall within 'binner'
end-points.
closed : which end of bin is closed; left (default), right
Returns
-------
bins : array of offsets (into 'values' argument) of bins.
Zero and last edge are excluded in result, so for instance the first
bin is values[0:bin[0]] and the last is values[bin[-1]:]
"""
lenidx = len(values)
lenbin = len(binner)
if lenidx <= 0 or lenbin <= 0:
raise ValueError("Invalid length for values or for binner")
# check binner fits data
if values[0] < binner[0]:
raise ValueError("Values falls before first bin")
if values[lenidx - 1] > binner[lenbin - 1]:
raise ValueError("Values falls after last bin")
bins = np.empty(lenbin - 1, dtype=np.int64)
j = 0 # index into values
bc = 0 # bin count
# linear scan, presume nothing about values/binner except that it fits ok
for i in range(0, lenbin - 1):
r_bin = binner[i + 1]
# count values in current bin, advance to next bin
while j < lenidx and (
values[j] < r_bin or (closed == "right" and values[j] == r_bin)
):
j += 1
bins[bc] = j
bc += 1
return bins
class BaseGrouper:
"""
This is an internal Grouper class, which actually holds
the generated groups
Parameters
----------
axis : int
the axis to group
groupings : array of grouping
all the grouping instances to handle in this grouper
for example for grouper list to groupby, need to pass the list
sort : boolean, default True
whether this grouper will give sorted result or not
group_keys : boolean, default True
mutated : boolean, default False
indexer : intp array, optional
the indexer created by Grouper
some groupers (TimeGrouper) will sort its axis and its
group_info is also sorted, so need the indexer to reorder
"""
def __init__(
self, axis, groupings, sort=True, group_keys=True, mutated=False, indexer=None
):
self._filter_empty_groups = self.compressed = len(groupings) != 1
self.axis = axis
self.groupings = groupings
self.sort = sort
self.group_keys = group_keys
self.mutated = mutated
self.indexer = indexer
@property
def shape(self):
return tuple(ping.ngroups for ping in self.groupings)
def __iter__(self):
return iter(self.indices)
@property
def nkeys(self):
return len(self.groupings)
def get_iterator(self, data, axis=0):
"""
Groupby iterator
Returns
-------
Generator yielding sequence of (name, subsetted object)
for each group
"""
splitter = self._get_splitter(data, axis=axis)
keys = self._get_group_keys()
for key, (i, group) in zip(keys, splitter):
yield key, group
def _get_splitter(self, data, axis=0):
comp_ids, _, ngroups = self.group_info
return get_splitter(data, comp_ids, ngroups, axis=axis)
def _get_grouper(self):
"""
We are a grouper as part of another's groupings.
We have a specific method of grouping, so cannot
convert to a Index for our grouper.
"""
return self.groupings[0].grouper
def _get_group_keys(self):
if len(self.groupings) == 1:
return self.levels[0]
else:
comp_ids, _, ngroups = self.group_info
# provide "flattened" iterator for multi-group setting
return get_flattened_iterator(comp_ids, ngroups, self.levels, self.labels)
def apply(self, f, data, axis=0):
mutated = self.mutated
splitter = self._get_splitter(data, axis=axis)
group_keys = self._get_group_keys()
result_values = None
# oh boy
f_name = com.get_callable_name(f)
if (
f_name not in base.plotting_methods
and hasattr(splitter, "fast_apply")
and axis == 0
):
try:
result_values, mutated = splitter.fast_apply(f, group_keys)
# If the fast apply path could be used we can return here.
# Otherwise we need to fall back to the slow implementation.
if len(result_values) == len(group_keys):
return group_keys, result_values, mutated
except libreduction.InvalidApply:
# Cannot fast apply on MultiIndex (_has_complex_internals).
# This Exception is also raised if `f` triggers an exception
# but it is preferable to raise the exception in Python.
pass
except TypeError as err:
if "Cannot convert" in str(err):
# via apply_frame_axis0 if we pass a non-ndarray
pass
else:
raise
for key, (i, group) in zip(group_keys, splitter):
object.__setattr__(group, "name", key)
# result_values is None if fast apply path wasn't taken
# or fast apply aborted with an unexpected exception.
# In either case, initialize the result list and perform
# the slow iteration.
if result_values is None:
result_values = []
# If result_values is not None we're in the case that the
# fast apply loop was broken prematurely but we have
# already the result for the first group which we can reuse.
elif i == 0:
continue
# group might be modified
group_axes = _get_axes(group)
res = f(group)
if not _is_indexed_like(res, group_axes):
mutated = True
result_values.append(res)
return group_keys, result_values, mutated
@cache_readonly
def indices(self):
""" dict {group name -> group indices} """
if len(self.groupings) == 1:
return self.groupings[0].indices
else:
label_list = [ping.labels for ping in self.groupings]
keys = [com.values_from_object(ping.group_index) for ping in self.groupings]
return get_indexer_dict(label_list, keys)
@property
def labels(self):
return [ping.labels for ping in self.groupings]
@property
def levels(self):
return [ping.group_index for ping in self.groupings]
@property
def names(self):
return [ping.name for ping in self.groupings]
def size(self):
"""
Compute group sizes
"""
ids, _, ngroup = self.group_info
ids = ensure_platform_int(ids)
if ngroup:
out = np.bincount(ids[ids != -1], minlength=ngroup)
else:
out = []
return Series(out, index=self.result_index, dtype="int64")
@cache_readonly
def groups(self):
""" dict {group name -> group labels} """
if len(self.groupings) == 1:
return self.groupings[0].groups
else:
to_groupby = zip(*(ping.grouper for ping in self.groupings))
to_groupby = Index(to_groupby)
return self.axis.groupby(to_groupby)
@cache_readonly
def is_monotonic(self):
# return if my group orderings are monotonic
return Index(self.group_info[0]).is_monotonic
@cache_readonly
def group_info(self):
comp_ids, obs_group_ids = self._get_compressed_labels()
ngroups = len(obs_group_ids)
comp_ids = ensure_int64(comp_ids)
return comp_ids, obs_group_ids, ngroups
@cache_readonly
def label_info(self):
# return the labels of items in original grouped axis
labels, _, _ = self.group_info
if self.indexer is not None:
sorter = np.lexsort((labels, self.indexer))
labels = labels[sorter]
return labels
def _get_compressed_labels(self):
all_labels = [ping.labels for ping in self.groupings]
if len(all_labels) > 1:
group_index = get_group_index(all_labels, self.shape, sort=True, xnull=True)
return compress_group_index(group_index, sort=self.sort)
ping = self.groupings[0]
return ping.labels, np.arange(len(ping.group_index))
@cache_readonly
def ngroups(self):
return len(self.result_index)
@property
def recons_labels(self):
comp_ids, obs_ids, _ = self.group_info
labels = (ping.labels for ping in self.groupings)
return decons_obs_group_ids(comp_ids, obs_ids, self.shape, labels, xnull=True)
@cache_readonly
def result_index(self):
if not self.compressed and len(self.groupings) == 1:
return self.groupings[0].result_index.rename(self.names[0])
codes = self.recons_labels
levels = [ping.result_index for ping in self.groupings]
result = MultiIndex(
levels=levels, codes=codes, verify_integrity=False, names=self.names
)
return result
def get_group_levels(self):
if not self.compressed and len(self.groupings) == 1:
return [self.groupings[0].result_index]
name_list = []
for ping, labels in zip(self.groupings, self.recons_labels):
labels = ensure_platform_int(labels)
levels = ping.result_index.take(labels)
name_list.append(levels)
return name_list
# ------------------------------------------------------------
# Aggregation functions
_cython_functions = {
"aggregate": {
"add": "group_add",
"prod": "group_prod",
"min": "group_min",
"max": "group_max",
"mean": "group_mean",
"median": {"name": "group_median"},
"var": "group_var",
"first": {
"name": "group_nth",
"f": lambda func, a, b, c, d, e: func(a, b, c, d, 1, -1),
},
"last": "group_last",
"ohlc": "group_ohlc",
},
"transform": {
"cumprod": "group_cumprod",
"cumsum": "group_cumsum",
"cummin": "group_cummin",
"cummax": "group_cummax",
"rank": {
"name": "group_rank",
"f": lambda func, a, b, c, d, e, **kwargs: func(
a,
b,
c,
e,
kwargs.get("ties_method", "average"),
kwargs.get("ascending", True),
kwargs.get("pct", False),
kwargs.get("na_option", "keep"),
),
},
},
}
_cython_arity = {"ohlc": 4} # OHLC
_name_functions = {"ohlc": lambda *args: ["open", "high", "low", "close"]}
def _is_builtin_func(self, arg):
"""
if we define an builtin function for this argument, return it,
otherwise return the arg
"""
return SelectionMixin._builtin_table.get(arg, arg)
def _get_cython_function(self, kind, how, values, is_numeric):
dtype_str = values.dtype.name
def get_func(fname):
# see if there is a fused-type version of function
# only valid for numeric
f = getattr(libgroupby, fname, None)
if f is not None and is_numeric:
return f
# otherwise find dtype-specific version, falling back to object
for dt in [dtype_str, "object"]:
f2 = getattr(
libgroupby,
"{fname}_{dtype_str}".format(fname=fname, dtype_str=dt),
None,
)
if f2 is not None:
return f2
if hasattr(f, "__signatures__"):
# inspect what fused types are implemented
if dtype_str == "object" and "object" not in f.__signatures__:
# return None so we get a NotImplementedError below
# instead of a TypeError at runtime
return None
return f
ftype = self._cython_functions[kind][how]
if isinstance(ftype, dict):
func = afunc = get_func(ftype["name"])
# a sub-function
f = ftype.get("f")
if f is not None:
def wrapper(*args, **kwargs):
return f(afunc, *args, **kwargs)
# need to curry our sub-function
func = wrapper
else:
func = get_func(ftype)
if func is None:
raise NotImplementedError(
"function is not implemented for this dtype: "
"[how->{how},dtype->{dtype_str}]".format(how=how, dtype_str=dtype_str)
)
return func
def _cython_operation(self, kind, values, how, axis, min_count=-1, **kwargs):
assert kind in ["transform", "aggregate"]
orig_values = values
# can we do this operation with our cython functions
# if not raise NotImplementedError
# we raise NotImplemented if this is an invalid operation
# entirely, e.g. adding datetimes
# categoricals are only 1d, so we
# are not setup for dim transforming
if is_categorical_dtype(values) or is_sparse(values):
raise NotImplementedError("{} dtype not supported".format(values.dtype))
elif is_datetime64_any_dtype(values):
if how in ["add", "prod", "cumsum", "cumprod"]:
raise NotImplementedError(
"datetime64 type does not support {} operations".format(how)
)
elif is_timedelta64_dtype(values):
if how in ["prod", "cumprod"]:
raise NotImplementedError(
"timedelta64 type does not support {} operations".format(how)
)
if is_datetime64tz_dtype(values.dtype):
# Cast to naive; we'll cast back at the end of the function
# TODO: possible need to reshape? kludge can be avoided when
# 2D EA is allowed.
values = values.view("M8[ns]")
is_datetimelike = needs_i8_conversion(values.dtype)
is_numeric = is_numeric_dtype(values.dtype)
if is_datetimelike:
values = values.view("int64")
is_numeric = True
elif is_bool_dtype(values.dtype):
values = ensure_float64(values)
elif is_integer_dtype(values):
# we use iNaT for the missing value on ints
# so pre-convert to guard this condition
if (values == iNaT).any():
values = ensure_float64(values)
else:
values = ensure_int_or_float(values)
elif is_numeric and not is_complex_dtype(values):
values = ensure_float64(values)
else:
values = values.astype(object)
arity = self._cython_arity.get(how, 1)
vdim = values.ndim
swapped = False
if vdim == 1:
values = values[:, None]
out_shape = (self.ngroups, arity)
else:
if axis > 0:
swapped = True
assert axis == 1, axis
values = values.T
if arity > 1:
raise NotImplementedError(
"arity of more than 1 is not supported for the 'how' argument"
)
out_shape = (self.ngroups,) + values.shape[1:]
try:
func = self._get_cython_function(kind, how, values, is_numeric)
except NotImplementedError:
if is_numeric:
try:
values = ensure_float64(values)
except TypeError:
if lib.infer_dtype(values, skipna=False) == "complex":
values = values.astype(complex)
else:
raise
func = self._get_cython_function(kind, how, values, is_numeric)
else:
raise
if how == "rank":
out_dtype = "float"
else:
if is_numeric:
out_dtype = "{kind}{itemsize}".format(
kind=values.dtype.kind, itemsize=values.dtype.itemsize
)
else:
out_dtype = "object"
labels, _, _ = self.group_info
if kind == "aggregate":
result = _maybe_fill(
np.empty(out_shape, dtype=out_dtype), fill_value=np.nan
)
counts = np.zeros(self.ngroups, dtype=np.int64)
result = self._aggregate(
result,
counts,
values,
labels,
func,
is_numeric,
is_datetimelike,
min_count,
)
elif kind == "transform":
result = _maybe_fill(
np.empty_like(values, dtype=out_dtype), fill_value=np.nan
)
# TODO: min_count
result = self._transform(
result, values, labels, func, is_numeric, is_datetimelike, **kwargs
)
if is_integer_dtype(result) and not is_datetimelike:
mask = result == iNaT
if mask.any():
result = result.astype("float64")
result[mask] = np.nan
if kind == "aggregate" and self._filter_empty_groups and not counts.all():
assert result.ndim != 2
result = result[counts > 0]
if vdim == 1 and arity == 1:
result = result[:, 0]
if how in self._name_functions:
# TODO
names = self._name_functions[how]()
else:
names = None
if swapped:
result = result.swapaxes(0, axis)
if is_datetime64tz_dtype(orig_values.dtype):
result = type(orig_values)(result.astype(np.int64), dtype=orig_values.dtype)
elif is_datetimelike and kind == "aggregate":
result = result.astype(orig_values.dtype)
return result, names
def aggregate(self, values, how, axis=0, min_count=-1):
return self._cython_operation(
"aggregate", values, how, axis, min_count=min_count
)
def transform(self, values, how, axis=0, **kwargs):
return self._cython_operation("transform", values, how, axis, **kwargs)
def _aggregate(
self,
result,
counts,
values,
comp_ids,
agg_func,
is_numeric,
is_datetimelike,
min_count=-1,
):
if values.ndim > 2:
# punting for now
raise NotImplementedError("number of dimensions is currently limited to 2")
else:
agg_func(result, counts, values, comp_ids, min_count)
return result
def _transform(
self,
result,
values,
comp_ids,
transform_func,
is_numeric,
is_datetimelike,
**kwargs
):
comp_ids, _, ngroups = self.group_info
if values.ndim > 2:
# punting for now
raise NotImplementedError("number of dimensions is currently limited to 2")
else:
transform_func(result, values, comp_ids, ngroups, is_datetimelike, **kwargs)
return result
def agg_series(self, obj, func):
try:
return self._aggregate_series_fast(obj, func)
except AssertionError:
raise
except ValueError as err:
if "No result." in str(err):
# raised in libreduction
pass
elif "Function does not reduce" in str(err):
# raised in libreduction
pass
else:
raise
except TypeError as err:
if "ndarray" in str(err):
# raised in libreduction if obj's values is no ndarray
pass
else:
raise
return self._aggregate_series_pure_python(obj, func)
def _aggregate_series_fast(self, obj, func):
func = self._is_builtin_func(func)
if obj.index._has_complex_internals:
raise TypeError("Incompatible index for Cython grouper")
group_index, _, ngroups = self.group_info
# avoids object / Series creation overhead
dummy = obj._get_values(slice(None, 0))
indexer = get_group_index_sorter(group_index, ngroups)
obj = obj.take(indexer)
group_index = algorithms.take_nd(group_index, indexer, allow_fill=False)
grouper = libreduction.SeriesGrouper(obj, func, group_index, ngroups, dummy)
result, counts = grouper.get_result()
return result, counts
def _aggregate_series_pure_python(self, obj, func):
group_index, _, ngroups = self.group_info
counts = np.zeros(ngroups, dtype=int)
result = None
splitter = get_splitter(obj, group_index, ngroups, axis=self.axis)
for label, group in splitter:
res = func(group)
if result is None:
if isinstance(res, (Series, Index, np.ndarray)):
raise ValueError("Function does not reduce")
result = np.empty(ngroups, dtype="O")
counts[label] = group.shape[0]
result[label] = res
result = lib.maybe_convert_objects(result, try_float=0)
return result, counts
class BinGrouper(BaseGrouper):
"""
This is an internal Grouper class
Parameters
----------
bins : the split index of binlabels to group the item of axis
binlabels : the label list
filter_empty : boolean, default False
mutated : boolean, default False
indexer : a intp array
Examples
--------
bins: [2, 4, 6, 8, 10]
binlabels: DatetimeIndex(['2005-01-01', '2005-01-03',
'2005-01-05', '2005-01-07', '2005-01-09'],
dtype='datetime64[ns]', freq='2D')
the group_info, which contains the label of each item in grouped
axis, the index of label in label list, group number, is
(array([0, 0, 1, 1, 2, 2, 3, 3, 4, 4]), array([0, 1, 2, 3, 4]), 5)
means that, the grouped axis has 10 items, can be grouped into 5
labels, the first and second items belong to the first label, the
third and forth items belong to the second label, and so on
"""
def __init__(
self, bins, binlabels, filter_empty=False, mutated=False, indexer=None
):
self.bins = ensure_int64(bins)
self.binlabels = ensure_index(binlabels)
self._filter_empty_groups = filter_empty
self.mutated = mutated
self.indexer = indexer
@cache_readonly
def groups(self):
""" dict {group name -> group labels} """
# this is mainly for compat
# GH 3881
result = {
key: value
for key, value in zip(self.binlabels, self.bins)
if key is not NaT
}
return result
@property
def nkeys(self):
return 1
def _get_grouper(self):
"""
We are a grouper as part of another's groupings.
We have a specific method of grouping, so cannot
convert to a Index for our grouper.
"""
return self
def get_iterator(self, data, axis=0):
"""
Groupby iterator
Returns
-------
Generator yielding sequence of (name, subsetted object)
for each group
"""
if isinstance(data, NDFrame):
slicer = lambda start, edge: data._slice(slice(start, edge), axis=axis)
length = len(data.axes[axis])
else:
slicer = lambda start, edge: data[slice(start, edge)]
length = len(data)
start = 0
for edge, label in zip(self.bins, self.binlabels):
if label is not NaT:
yield label, slicer(start, edge)
start = edge
if start < length:
yield self.binlabels[-1], slicer(start, None)
@cache_readonly
def indices(self):
indices = collections.defaultdict(list)
i = 0
for label, bin in zip(self.binlabels, self.bins):
if i < bin:
if label is not NaT:
indices[label] = list(range(i, bin))
i = bin
return indices
@cache_readonly
def group_info(self):
ngroups = self.ngroups
obs_group_ids = np.arange(ngroups)
rep = np.diff(np.r_[0, self.bins])
rep = ensure_platform_int(rep)
if ngroups == len(self.bins):
comp_ids = np.repeat(np.arange(ngroups), rep)
else:
comp_ids = np.repeat(np.r_[-1, np.arange(ngroups)], rep)
return (
comp_ids.astype("int64", copy=False),
obs_group_ids.astype("int64", copy=False),
ngroups,
)
@cache_readonly
def result_index(self):
if len(self.binlabels) != 0 and isna(self.binlabels[0]):
return self.binlabels[1:]
return self.binlabels
@property
def levels(self):
return [self.binlabels]
@property
def names(self):
return [self.binlabels.name]
@property
def groupings(self):
from pandas.core.groupby.grouper import Grouping
return [
Grouping(lvl, lvl, in_axis=False, level=None, name=name)
for lvl, name in zip(self.levels, self.names)
]
def agg_series(self, obj, func):
dummy = obj[:0]
grouper = libreduction.SeriesBinGrouper(obj, func, self.bins, dummy)
return grouper.get_result()
def _get_axes(group):
if isinstance(group, Series):
return [group.index]
else:
return group.axes
def _is_indexed_like(obj, axes):
if isinstance(obj, Series):
if len(axes) > 1:
return False
return obj.index.equals(axes[0])
elif isinstance(obj, DataFrame):
return obj.index.equals(axes[0])
return False
# ----------------------------------------------------------------------
# Splitting / application
class DataSplitter:
def __init__(self, data, labels, ngroups, axis=0):
self.data = data
self.labels = ensure_int64(labels)
self.ngroups = ngroups
self.axis = axis
@cache_readonly
def slabels(self):
# Sorted labels
return algorithms.take_nd(self.labels, self.sort_idx, allow_fill=False)
@cache_readonly
def sort_idx(self):
# Counting sort indexer
return get_group_index_sorter(self.labels, self.ngroups)
def __iter__(self):
sdata = self._get_sorted_data()
if self.ngroups == 0:
# we are inside a generator, rather than raise StopIteration
# we merely return signal the end
return
starts, ends = lib.generate_slices(self.slabels, self.ngroups)
for i, (start, end) in enumerate(zip(starts, ends)):
# Since I'm now compressing the group ids, it's now not "possible"
# to produce empty slices because such groups would not be observed
# in the data
# if start >= end:
# raise AssertionError('Start %s must be less than end %s'
# % (str(start), str(end)))
yield i, self._chop(sdata, slice(start, end))
def _get_sorted_data(self):
return self.data.take(self.sort_idx, axis=self.axis)
def _chop(self, sdata, slice_obj):
raise AbstractMethodError(self)
def apply(self, f):
raise AbstractMethodError(self)
class SeriesSplitter(DataSplitter):
def _chop(self, sdata, slice_obj):
return sdata._get_values(slice_obj)
class FrameSplitter(DataSplitter):
def fast_apply(self, f, names):
# must return keys::list, values::list, mutated::bool
starts, ends = lib.generate_slices(self.slabels, self.ngroups)
sdata = self._get_sorted_data()
return libreduction.apply_frame_axis0(sdata, f, names, starts, ends)
def _chop(self, sdata, slice_obj):
if self.axis == 0:
return sdata.iloc[slice_obj]
else:
return sdata._slice(slice_obj, axis=1)
def get_splitter(data, *args, **kwargs):
if isinstance(data, Series):
klass = SeriesSplitter
elif isinstance(data, DataFrame):
klass = FrameSplitter
return klass(data, *args, **kwargs)
| BugsInPy/BugsInPy/temp/projects/pandas/bug-135-fixed/pandas/pandas/core/groupby/ops.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-135-buggy/pandas/pandas/core/groupby/ops.py |
pandas-bug-83 | import textwrap
from typing import List, Set
from pandas._libs import NaT, lib
import pandas.core.common as com
from pandas.core.indexes.base import (
Index,
InvalidIndexError,
_new_Index,
ensure_index,
ensure_index_from_sequences,
)
from pandas.core.indexes.category import CategoricalIndex
from pandas.core.indexes.datetimes import DatetimeIndex
from pandas.core.indexes.interval import IntervalIndex
from pandas.core.indexes.multi import MultiIndex
from pandas.core.indexes.numeric import (
Float64Index,
Int64Index,
NumericIndex,
UInt64Index,
)
from pandas.core.indexes.period import PeriodIndex
from pandas.core.indexes.range import RangeIndex
from pandas.core.indexes.timedeltas import TimedeltaIndex
_sort_msg = textwrap.dedent(
"""\
Sorting because non-concatenation axis is not aligned. A future version
of pandas will change to not sort by default.
To accept the future behavior, pass 'sort=False'.
To retain the current behavior and silence the warning, pass 'sort=True'.
"""
)
__all__ = [
"Index",
"MultiIndex",
"NumericIndex",
"Float64Index",
"Int64Index",
"CategoricalIndex",
"IntervalIndex",
"RangeIndex",
"UInt64Index",
"InvalidIndexError",
"TimedeltaIndex",
"PeriodIndex",
"DatetimeIndex",
"_new_Index",
"NaT",
"ensure_index",
"ensure_index_from_sequences",
"get_objs_combined_axis",
"union_indexes",
"get_consensus_names",
"all_indexes_same",
]
def get_objs_combined_axis(
objs, intersect: bool = False, axis=0, sort: bool = True
) -> Index:
"""
Extract combined index: return intersection or union (depending on the
value of "intersect") of indexes on given axis, or None if all objects
lack indexes (e.g. they are numpy arrays).
Parameters
----------
objs : list
Series or DataFrame objects, may be mix of the two.
intersect : bool, default False
If True, calculate the intersection between indexes. Otherwise,
calculate the union.
axis : {0 or 'index', 1 or 'outer'}, default 0
The axis to extract indexes from.
sort : bool, default True
Whether the result index should come out sorted or not.
Returns
-------
Index
"""
obs_idxes = [obj._get_axis(axis) for obj in objs]
return _get_combined_index(obs_idxes, intersect=intersect, sort=sort)
def _get_distinct_objs(objs: List[Index]) -> List[Index]:
"""
Return a list with distinct elements of "objs" (different ids).
Preserves order.
"""
ids: Set[int] = set()
res = []
for obj in objs:
if id(obj) not in ids:
ids.add(id(obj))
res.append(obj)
return res
def _get_combined_index(
indexes: List[Index], intersect: bool = False, sort: bool = False
) -> Index:
"""
Return the union or intersection of indexes.
Parameters
----------
indexes : list of Index or list objects
When intersect=True, do not accept list of lists.
intersect : bool, default False
If True, calculate the intersection between indexes. Otherwise,
calculate the union.
sort : bool, default False
Whether the result index should come out sorted or not.
Returns
-------
Index
"""
# TODO: handle index names!
indexes = _get_distinct_objs(indexes)
if len(indexes) == 0:
index = Index([])
elif len(indexes) == 1:
index = indexes[0]
elif intersect:
index = indexes[0]
for other in indexes[1:]:
index = index.intersection(other)
else:
index = union_indexes(indexes, sort=sort)
index = ensure_index(index)
if sort:
try:
index = index.sort_values()
except TypeError:
pass
return index
def union_indexes(indexes, sort=True) -> Index:
"""
Return the union of indexes.
The behavior of sort and names is not consistent.
Parameters
----------
indexes : list of Index or list objects
sort : bool, default True
Whether the result index should come out sorted or not.
Returns
-------
Index
"""
if len(indexes) == 0:
raise AssertionError("Must have at least 1 Index to union")
if len(indexes) == 1:
result = indexes[0]
if isinstance(result, list):
result = Index(sorted(result))
return result
indexes, kind = _sanitize_and_check(indexes)
def _unique_indices(inds) -> Index:
"""
Convert indexes to lists and concatenate them, removing duplicates.
The final dtype is inferred.
Parameters
----------
inds : list of Index or list objects
Returns
-------
Index
"""
def conv(i):
if isinstance(i, Index):
i = i.tolist()
return i
return Index(lib.fast_unique_multiple_list([conv(i) for i in inds], sort=sort))
if kind == "special":
result = indexes[0]
if hasattr(result, "union_many"):
# DatetimeIndex
return result.union_many(indexes[1:])
else:
for other in indexes[1:]:
result = result.union(other)
return result
elif kind == "array":
index = indexes[0]
for other in indexes[1:]:
if not index.equals(other):
return _unique_indices(indexes)
name = get_consensus_names(indexes)[0]
if name != index.name:
index = index._shallow_copy(name=name)
return index
else: # kind='list'
return _unique_indices(indexes)
def _sanitize_and_check(indexes):
"""
Verify the type of indexes and convert lists to Index.
Cases:
- [list, list, ...]: Return ([list, list, ...], 'list')
- [list, Index, ...]: Return _sanitize_and_check([Index, Index, ...])
Lists are sorted and converted to Index.
- [Index, Index, ...]: Return ([Index, Index, ...], TYPE)
TYPE = 'special' if at least one special type, 'array' otherwise.
Parameters
----------
indexes : list of Index or list objects
Returns
-------
sanitized_indexes : list of Index or list objects
type : {'list', 'array', 'special'}
"""
kinds = list({type(index) for index in indexes})
if list in kinds:
if len(kinds) > 1:
indexes = [
Index(com.try_sort(x)) if not isinstance(x, Index) else x
for x in indexes
]
kinds.remove(list)
else:
return indexes, "list"
if len(kinds) > 1 or Index not in kinds:
return indexes, "special"
else:
return indexes, "array"
def get_consensus_names(indexes):
"""
Give a consensus 'names' to indexes.
If there's exactly one non-empty 'names', return this,
otherwise, return empty.
Parameters
----------
indexes : list of Index objects
Returns
-------
list
A list representing the consensus 'names' found.
"""
# find the non-none names, need to tupleify to make
# the set hashable, then reverse on return
consensus_names = {tuple(i.names) for i in indexes if com.any_not_none(*i.names)}
if len(consensus_names) == 1:
return list(list(consensus_names)[0])
return [None] * indexes[0].nlevels
def all_indexes_same(indexes):
"""
Determine if all indexes contain the same elements.
Parameters
----------
indexes : list of Index objects
Returns
-------
bool
True if all indexes contain the same elements, False otherwise.
"""
first = indexes[0]
for index in indexes[1:]:
if not first.equals(index):
return False
return True
import textwrap
from typing import List, Set
from pandas._libs import NaT, lib
import pandas.core.common as com
from pandas.core.indexes.base import (
Index,
InvalidIndexError,
_new_Index,
ensure_index,
ensure_index_from_sequences,
)
from pandas.core.indexes.category import CategoricalIndex
from pandas.core.indexes.datetimes import DatetimeIndex
from pandas.core.indexes.interval import IntervalIndex
from pandas.core.indexes.multi import MultiIndex
from pandas.core.indexes.numeric import (
Float64Index,
Int64Index,
NumericIndex,
UInt64Index,
)
from pandas.core.indexes.period import PeriodIndex
from pandas.core.indexes.range import RangeIndex
from pandas.core.indexes.timedeltas import TimedeltaIndex
_sort_msg = textwrap.dedent(
"""\
Sorting because non-concatenation axis is not aligned. A future version
of pandas will change to not sort by default.
To accept the future behavior, pass 'sort=False'.
To retain the current behavior and silence the warning, pass 'sort=True'.
"""
)
__all__ = [
"Index",
"MultiIndex",
"NumericIndex",
"Float64Index",
"Int64Index",
"CategoricalIndex",
"IntervalIndex",
"RangeIndex",
"UInt64Index",
"InvalidIndexError",
"TimedeltaIndex",
"PeriodIndex",
"DatetimeIndex",
"_new_Index",
"NaT",
"ensure_index",
"ensure_index_from_sequences",
"get_objs_combined_axis",
"union_indexes",
"get_consensus_names",
"all_indexes_same",
]
def get_objs_combined_axis(
objs, intersect: bool = False, axis=0, sort: bool = True, copy: bool = False
) -> Index:
"""
Extract combined index: return intersection or union (depending on the
value of "intersect") of indexes on given axis, or None if all objects
lack indexes (e.g. they are numpy arrays).
Parameters
----------
objs : list
Series or DataFrame objects, may be mix of the two.
intersect : bool, default False
If True, calculate the intersection between indexes. Otherwise,
calculate the union.
axis : {0 or 'index', 1 or 'outer'}, default 0
The axis to extract indexes from.
sort : bool, default True
Whether the result index should come out sorted or not.
copy : bool, default False
If True, return a copy of the combined index.
Returns
-------
Index
"""
obs_idxes = [obj._get_axis(axis) for obj in objs]
return _get_combined_index(obs_idxes, intersect=intersect, sort=sort, copy=copy)
def _get_distinct_objs(objs: List[Index]) -> List[Index]:
"""
Return a list with distinct elements of "objs" (different ids).
Preserves order.
"""
ids: Set[int] = set()
res = []
for obj in objs:
if id(obj) not in ids:
ids.add(id(obj))
res.append(obj)
return res
def _get_combined_index(
indexes: List[Index],
intersect: bool = False,
sort: bool = False,
copy: bool = False,
) -> Index:
"""
Return the union or intersection of indexes.
Parameters
----------
indexes : list of Index or list objects
When intersect=True, do not accept list of lists.
intersect : bool, default False
If True, calculate the intersection between indexes. Otherwise,
calculate the union.
sort : bool, default False
Whether the result index should come out sorted or not.
copy : bool, default False
If True, return a copy of the combined index.
Returns
-------
Index
"""
# TODO: handle index names!
indexes = _get_distinct_objs(indexes)
if len(indexes) == 0:
index = Index([])
elif len(indexes) == 1:
index = indexes[0]
elif intersect:
index = indexes[0]
for other in indexes[1:]:
index = index.intersection(other)
else:
index = union_indexes(indexes, sort=sort)
index = ensure_index(index)
if sort:
try:
index = index.sort_values()
except TypeError:
pass
# GH 29879
if copy:
index = index.copy()
return index
def union_indexes(indexes, sort=True) -> Index:
"""
Return the union of indexes.
The behavior of sort and names is not consistent.
Parameters
----------
indexes : list of Index or list objects
sort : bool, default True
Whether the result index should come out sorted or not.
Returns
-------
Index
"""
if len(indexes) == 0:
raise AssertionError("Must have at least 1 Index to union")
if len(indexes) == 1:
result = indexes[0]
if isinstance(result, list):
result = Index(sorted(result))
return result
indexes, kind = _sanitize_and_check(indexes)
def _unique_indices(inds) -> Index:
"""
Convert indexes to lists and concatenate them, removing duplicates.
The final dtype is inferred.
Parameters
----------
inds : list of Index or list objects
Returns
-------
Index
"""
def conv(i):
if isinstance(i, Index):
i = i.tolist()
return i
return Index(lib.fast_unique_multiple_list([conv(i) for i in inds], sort=sort))
if kind == "special":
result = indexes[0]
if hasattr(result, "union_many"):
# DatetimeIndex
return result.union_many(indexes[1:])
else:
for other in indexes[1:]:
result = result.union(other)
return result
elif kind == "array":
index = indexes[0]
for other in indexes[1:]:
if not index.equals(other):
return _unique_indices(indexes)
name = get_consensus_names(indexes)[0]
if name != index.name:
index = index._shallow_copy(name=name)
return index
else: # kind='list'
return _unique_indices(indexes)
def _sanitize_and_check(indexes):
"""
Verify the type of indexes and convert lists to Index.
Cases:
- [list, list, ...]: Return ([list, list, ...], 'list')
- [list, Index, ...]: Return _sanitize_and_check([Index, Index, ...])
Lists are sorted and converted to Index.
- [Index, Index, ...]: Return ([Index, Index, ...], TYPE)
TYPE = 'special' if at least one special type, 'array' otherwise.
Parameters
----------
indexes : list of Index or list objects
Returns
-------
sanitized_indexes : list of Index or list objects
type : {'list', 'array', 'special'}
"""
kinds = list({type(index) for index in indexes})
if list in kinds:
if len(kinds) > 1:
indexes = [
Index(com.try_sort(x)) if not isinstance(x, Index) else x
for x in indexes
]
kinds.remove(list)
else:
return indexes, "list"
if len(kinds) > 1 or Index not in kinds:
return indexes, "special"
else:
return indexes, "array"
def get_consensus_names(indexes):
"""
Give a consensus 'names' to indexes.
If there's exactly one non-empty 'names', return this,
otherwise, return empty.
Parameters
----------
indexes : list of Index objects
Returns
-------
list
A list representing the consensus 'names' found.
"""
# find the non-none names, need to tupleify to make
# the set hashable, then reverse on return
consensus_names = {tuple(i.names) for i in indexes if com.any_not_none(*i.names)}
if len(consensus_names) == 1:
return list(list(consensus_names)[0])
return [None] * indexes[0].nlevels
def all_indexes_same(indexes):
"""
Determine if all indexes contain the same elements.
Parameters
----------
indexes : list of Index objects
Returns
-------
bool
True if all indexes contain the same elements, False otherwise.
"""
first = indexes[0]
for index in indexes[1:]:
if not first.equals(index):
return False
return True
| BugsInPy/BugsInPy/temp/projects/pandas/bug-83-fixed/pandas/pandas/core/indexes/api.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-83-buggy/pandas/pandas/core/indexes/api.py |
pandas-bug-51 | from typing import Any, List
import warnings
import numpy as np
from pandas._config import get_option
from pandas._libs import index as libindex
from pandas._libs.hashtable import duplicated_int64
from pandas._libs.lib import no_default
from pandas._typing import Label
from pandas.util._decorators import Appender, cache_readonly
from pandas.core.dtypes.common import (
ensure_platform_int,
is_categorical_dtype,
is_interval_dtype,
is_list_like,
is_scalar,
)
from pandas.core.dtypes.dtypes import CategoricalDtype
from pandas.core.dtypes.missing import isna
from pandas.core import accessor
from pandas.core.algorithms import take_1d
from pandas.core.arrays.categorical import Categorical, _recode_for_categories, contains
import pandas.core.common as com
import pandas.core.indexes.base as ibase
from pandas.core.indexes.base import Index, _index_shared_docs, maybe_extract_name
from pandas.core.indexes.extension import ExtensionIndex, inherit_names
import pandas.core.missing as missing
_index_doc_kwargs = dict(ibase._index_doc_kwargs)
_index_doc_kwargs.update(dict(target_klass="CategoricalIndex"))
@inherit_names(
[
"argsort",
"_internal_get_values",
"tolist",
"codes",
"categories",
"ordered",
"_reverse_indexer",
"searchsorted",
"is_dtype_equal",
"min",
"max",
],
Categorical,
)
@accessor.delegate_names(
delegate=Categorical,
accessors=[
"rename_categories",
"reorder_categories",
"add_categories",
"remove_categories",
"remove_unused_categories",
"set_categories",
"as_ordered",
"as_unordered",
],
typ="method",
overwrite=True,
)
class CategoricalIndex(ExtensionIndex, accessor.PandasDelegate):
"""
Index based on an underlying :class:`Categorical`.
CategoricalIndex, like Categorical, can only take on a limited,
and usually fixed, number of possible values (`categories`). Also,
like Categorical, it might have an order, but numerical operations
(additions, divisions, ...) are not possible.
Parameters
----------
data : array-like (1-dimensional)
The values of the categorical. If `categories` are given, values not in
`categories` will be replaced with NaN.
categories : index-like, optional
The categories for the categorical. Items need to be unique.
If the categories are not given here (and also not in `dtype`), they
will be inferred from the `data`.
ordered : bool, optional
Whether or not this categorical is treated as an ordered
categorical. If not given here or in `dtype`, the resulting
categorical will be unordered.
dtype : CategoricalDtype or "category", optional
If :class:`CategoricalDtype`, cannot be used together with
`categories` or `ordered`.
.. versionadded:: 0.21.0
copy : bool, default False
Make a copy of input ndarray.
name : object, optional
Name to be stored in the index.
Attributes
----------
codes
categories
ordered
Methods
-------
rename_categories
reorder_categories
add_categories
remove_categories
remove_unused_categories
set_categories
as_ordered
as_unordered
map
Raises
------
ValueError
If the categories do not validate.
TypeError
If an explicit ``ordered=True`` is given but no `categories` and the
`values` are not sortable.
See Also
--------
Index : The base pandas Index type.
Categorical : A categorical array.
CategoricalDtype : Type for categorical data.
Notes
-----
See the `user guide
<https://pandas.pydata.org/pandas-docs/stable/user_guide/advanced.html#categoricalindex>`_
for more.
Examples
--------
>>> pd.CategoricalIndex(['a', 'b', 'c', 'a', 'b', 'c'])
CategoricalIndex(['a', 'b', 'c', 'a', 'b', 'c'], categories=['a', 'b', 'c'], ordered=False, dtype='category') # noqa
``CategoricalIndex`` can also be instantiated from a ``Categorical``:
>>> c = pd.Categorical(['a', 'b', 'c', 'a', 'b', 'c'])
>>> pd.CategoricalIndex(c)
CategoricalIndex(['a', 'b', 'c', 'a', 'b', 'c'], categories=['a', 'b', 'c'], ordered=False, dtype='category') # noqa
Ordered ``CategoricalIndex`` can have a min and max value.
>>> ci = pd.CategoricalIndex(['a','b','c','a','b','c'], ordered=True,
... categories=['c', 'b', 'a'])
>>> ci
CategoricalIndex(['a', 'b', 'c', 'a', 'b', 'c'], categories=['c', 'b', 'a'], ordered=True, dtype='category') # noqa
>>> ci.min()
'c'
"""
_typ = "categoricalindex"
codes: np.ndarray
categories: Index
_data: Categorical
@property
def _engine_type(self):
# self.codes can have dtype int8, int16, int32 or int64, so we need
# to return the corresponding engine type (libindex.Int8Engine, etc.).
return {
np.int8: libindex.Int8Engine,
np.int16: libindex.Int16Engine,
np.int32: libindex.Int32Engine,
np.int64: libindex.Int64Engine,
}[self.codes.dtype.type]
_attributes = ["name"]
# --------------------------------------------------------------------
# Constructors
def __new__(
cls, data=None, categories=None, ordered=None, dtype=None, copy=False, name=None
):
dtype = CategoricalDtype._from_values_or_dtype(data, categories, ordered, dtype)
name = maybe_extract_name(name, data, cls)
if not is_categorical_dtype(data):
# don't allow scalars
# if data is None, then categories must be provided
if is_scalar(data):
if data is not None or categories is None:
raise cls._scalar_data_error(data)
data = []
assert isinstance(dtype, CategoricalDtype), dtype
if not isinstance(data, Categorical) or data.dtype != dtype:
data = Categorical(data, dtype=dtype)
data = data.copy() if copy else data
return cls._simple_new(data, name=name)
def _create_from_codes(self, codes, dtype=None, name=None):
"""
*this is an internal non-public method*
create the correct categorical from codes
Parameters
----------
codes : new codes
dtype: CategoricalDtype, defaults to existing
name : optional name attribute, defaults to existing
Returns
-------
CategoricalIndex
"""
if dtype is None:
dtype = self.dtype
if name is None:
name = self.name
cat = Categorical.from_codes(codes, dtype=dtype)
return CategoricalIndex(cat, name=name)
@classmethod
def _simple_new(cls, values: Categorical, name: Label = None):
assert isinstance(values, Categorical), type(values)
result = object.__new__(cls)
result._data = values
result.name = name
result._reset_identity()
result._no_setting_name = False
return result
# --------------------------------------------------------------------
@Appender(Index._shallow_copy.__doc__)
def _shallow_copy(self, values=None, name: Label = no_default):
name = self.name if name is no_default else name
if values is None:
values = self.values
cat = Categorical(values, dtype=self.dtype)
return type(self)._simple_new(cat, name=name)
def _is_dtype_compat(self, other) -> bool:
"""
*this is an internal non-public method*
provide a comparison between the dtype of self and other (coercing if
needed)
Raises
------
TypeError if the dtypes are not compatible
"""
if is_categorical_dtype(other):
if isinstance(other, CategoricalIndex):
other = other._values
if not other.is_dtype_equal(self):
raise TypeError(
"categories must match existing categories when appending"
)
else:
values = other
if not is_list_like(values):
values = [values]
cat = Categorical(other, dtype=self.dtype)
other = CategoricalIndex(cat)
if not other.isin(values).all():
raise TypeError(
"cannot append a non-category item to a CategoricalIndex"
)
return other
def equals(self, other) -> bool:
"""
Determine if two CategoricalIndex objects contain the same elements.
Returns
-------
bool
If two CategoricalIndex objects have equal elements True,
otherwise False.
"""
if self.is_(other):
return True
if not isinstance(other, Index):
return False
try:
other = self._is_dtype_compat(other)
if isinstance(other, type(self)):
other = other._data
return self._data.equals(other)
except (TypeError, ValueError):
pass
return False
# --------------------------------------------------------------------
# Rendering Methods
@property
def _formatter_func(self):
return self.categories._formatter_func
def _format_attrs(self):
"""
Return a list of tuples of the (attr,formatted_value)
"""
max_categories = (
10
if get_option("display.max_categories") == 0
else get_option("display.max_categories")
)
attrs = [
(
"categories",
ibase.default_pprint(self.categories, max_seq_items=max_categories),
),
("ordered", self.ordered),
]
if self.name is not None:
attrs.append(("name", ibase.default_pprint(self.name)))
attrs.append(("dtype", f"'{self.dtype.name}'"))
max_seq_items = get_option("display.max_seq_items") or len(self)
if len(self) > max_seq_items:
attrs.append(("length", len(self)))
return attrs
# --------------------------------------------------------------------
@property
def inferred_type(self) -> str:
return "categorical"
@property
def values(self):
""" return the underlying data, which is a Categorical """
return self._data
@property
def _has_complex_internals(self) -> bool:
# used to avoid libreduction code paths, which raise or require conversion
return True
@Appender(Index.__contains__.__doc__)
def __contains__(self, key: Any) -> bool:
# if key is a NaN, check if any NaN is in self.
if is_scalar(key) and isna(key):
return self.hasnans
hash(key)
return contains(self, key, container=self._engine)
def __array__(self, dtype=None) -> np.ndarray:
""" the array interface, return my values """
return np.array(self._data, dtype=dtype)
@Appender(Index.astype.__doc__)
def astype(self, dtype, copy=True):
if is_interval_dtype(dtype):
from pandas import IntervalIndex
return IntervalIndex(np.array(self))
elif is_categorical_dtype(dtype):
# GH 18630
dtype = self.dtype.update_dtype(dtype)
if dtype == self.dtype:
return self.copy() if copy else self
return Index.astype(self, dtype=dtype, copy=copy)
@cache_readonly
def _isnan(self):
""" return if each value is nan"""
return self._data.codes == -1
@Appender(Index.fillna.__doc__)
def fillna(self, value, downcast=None):
self._assert_can_do_op(value)
return CategoricalIndex(self._data.fillna(value), name=self.name)
@cache_readonly
def _engine(self):
# we are going to look things up with the codes themselves.
# To avoid a reference cycle, bind `codes` to a local variable, so
# `self` is not passed into the lambda.
codes = self.codes
return self._engine_type(lambda: codes, len(self))
@Appender(Index.unique.__doc__)
def unique(self, level=None):
if level is not None:
self._validate_index_level(level)
result = self.values.unique()
# Use _simple_new instead of _shallow_copy to ensure we keep dtype
# of result, not self.
return type(self)._simple_new(result, name=self.name)
@Appender(Index.duplicated.__doc__)
def duplicated(self, keep="first"):
codes = self.codes.astype("i8")
return duplicated_int64(codes, keep)
def _to_safe_for_reshape(self):
""" convert to object if we are a categorical """
return self.astype("object")
def _maybe_cast_indexer(self, key):
code = self.categories.get_loc(key)
code = self.codes.dtype.type(code)
return code
@Appender(Index.where.__doc__)
def where(self, cond, other=None):
# TODO: Investigate an alternative implementation with
# 1. copy the underlying Categorical
# 2. setitem with `cond` and `other`
# 3. Rebuild CategoricalIndex.
if other is None:
other = self._na_value
values = np.where(cond, self.values, other)
cat = Categorical(values, dtype=self.dtype)
return type(self)._simple_new(cat, name=self.name)
def reindex(self, target, method=None, level=None, limit=None, tolerance=None):
"""
Create index with target's values (move/add/delete values as necessary)
Returns
-------
new_index : pd.Index
Resulting index
indexer : np.ndarray or None
Indices of output values in original index
"""
if method is not None:
raise NotImplementedError(
"argument method is not implemented for CategoricalIndex.reindex"
)
if level is not None:
raise NotImplementedError(
"argument level is not implemented for CategoricalIndex.reindex"
)
if limit is not None:
raise NotImplementedError(
"argument limit is not implemented for CategoricalIndex.reindex"
)
target = ibase.ensure_index(target)
missing: List[int]
if self.equals(target):
indexer = None
missing = []
else:
indexer, missing = self.get_indexer_non_unique(np.array(target))
if len(self.codes) and indexer is not None:
new_target = self.take(indexer)
else:
new_target = target
# filling in missing if needed
if len(missing):
cats = self.categories.get_indexer(target)
if (cats == -1).any():
# coerce to a regular index here!
result = Index(np.array(self), name=self.name)
new_target, indexer, _ = result._reindex_non_unique(np.array(target))
else:
codes = new_target.codes.copy()
codes[indexer == -1] = cats[missing]
new_target = self._create_from_codes(codes)
# we always want to return an Index type here
# to be consistent with .reindex for other index types (e.g. they don't
# coerce based on the actual values, only on the dtype)
# unless we had an initial Categorical to begin with
# in which case we are going to conform to the passed Categorical
new_target = np.asarray(new_target)
if is_categorical_dtype(target):
new_target = target._shallow_copy(new_target, name=self.name)
else:
new_target = Index(new_target, name=self.name)
return new_target, indexer
def _reindex_non_unique(self, target):
"""
reindex from a non-unique; which CategoricalIndex's are almost
always
"""
new_target, indexer = self.reindex(target)
new_indexer = None
check = indexer == -1
if check.any():
new_indexer = np.arange(len(self.take(indexer)))
new_indexer[check] = -1
cats = self.categories.get_indexer(target)
if not (cats == -1).any():
# .reindex returns normal Index. Revert to CategoricalIndex if
# all targets are included in my categories
new_target = self._shallow_copy(new_target)
return new_target, indexer, new_indexer
@Appender(_index_shared_docs["get_indexer"] % _index_doc_kwargs)
def get_indexer(self, target, method=None, limit=None, tolerance=None):
method = missing.clean_reindex_fill_method(method)
target = ibase.ensure_index(target)
if self.is_unique and self.equals(target):
return np.arange(len(self), dtype="intp")
if method == "pad" or method == "backfill":
raise NotImplementedError(
"method='pad' and method='backfill' not "
"implemented yet for CategoricalIndex"
)
elif method == "nearest":
raise NotImplementedError(
"method='nearest' not implemented yet for CategoricalIndex"
)
if isinstance(target, CategoricalIndex) and self.values.is_dtype_equal(target):
if self.values.equals(target.values):
# we have the same codes
codes = target.codes
else:
codes = _recode_for_categories(
target.codes, target.categories, self.values.categories
)
else:
if isinstance(target, CategoricalIndex):
code_indexer = self.categories.get_indexer(target.categories)
codes = take_1d(code_indexer, target.codes, fill_value=-1)
else:
codes = self.categories.get_indexer(target)
indexer, _ = self._engine.get_indexer_non_unique(codes)
return ensure_platform_int(indexer)
@Appender(_index_shared_docs["get_indexer_non_unique"] % _index_doc_kwargs)
def get_indexer_non_unique(self, target):
target = ibase.ensure_index(target)
if isinstance(target, CategoricalIndex):
# Indexing on codes is more efficient if categories are the same:
if target.categories is self.categories:
target = target.codes
indexer, missing = self._engine.get_indexer_non_unique(target)
return ensure_platform_int(indexer), missing
target = target.values
codes = self.categories.get_indexer(target)
indexer, missing = self._engine.get_indexer_non_unique(codes)
return ensure_platform_int(indexer), missing
@Appender(Index._convert_scalar_indexer.__doc__)
def _convert_scalar_indexer(self, key, kind: str):
assert kind in ["loc", "getitem"]
if kind == "loc":
try:
return self.categories._convert_scalar_indexer(key, kind="loc")
except TypeError:
self._invalid_indexer("label", key)
return super()._convert_scalar_indexer(key, kind=kind)
@Appender(Index._convert_list_indexer.__doc__)
def _convert_list_indexer(self, keyarr):
# Return our indexer or raise if all of the values are not included in
# the categories
if self.categories._defer_to_indexing:
indexer = self.categories._convert_list_indexer(keyarr)
return Index(self.codes).get_indexer_for(indexer)
indexer = self.categories.get_indexer(np.asarray(keyarr))
if (indexer == -1).any():
raise KeyError(
"a list-indexer must only include values that are in the categories"
)
return self.get_indexer(keyarr)
@Appender(Index._convert_arr_indexer.__doc__)
def _convert_arr_indexer(self, keyarr):
keyarr = com.asarray_tuplesafe(keyarr)
if self.categories._defer_to_indexing:
return keyarr
return self._shallow_copy(keyarr)
@Appender(Index._convert_index_indexer.__doc__)
def _convert_index_indexer(self, keyarr):
return self._shallow_copy(keyarr)
def take_nd(self, *args, **kwargs):
"""Alias for `take`"""
warnings.warn(
"CategoricalIndex.take_nd is deprecated, use CategoricalIndex.take instead",
FutureWarning,
stacklevel=2,
)
return self.take(*args, **kwargs)
@Appender(Index._maybe_cast_slice_bound.__doc__)
def _maybe_cast_slice_bound(self, label, side, kind):
if kind == "loc":
return label
return super()._maybe_cast_slice_bound(label, side, kind)
def map(self, mapper):
"""
Map values using input correspondence (a dict, Series, or function).
Maps the values (their categories, not the codes) of the index to new
categories. If the mapping correspondence is one-to-one the result is a
:class:`~pandas.CategoricalIndex` which has the same order property as
the original, otherwise an :class:`~pandas.Index` is returned.
If a `dict` or :class:`~pandas.Series` is used any unmapped category is
mapped to `NaN`. Note that if this happens an :class:`~pandas.Index`
will be returned.
Parameters
----------
mapper : function, dict, or Series
Mapping correspondence.
Returns
-------
pandas.CategoricalIndex or pandas.Index
Mapped index.
See Also
--------
Index.map : Apply a mapping correspondence on an
:class:`~pandas.Index`.
Series.map : Apply a mapping correspondence on a
:class:`~pandas.Series`.
Series.apply : Apply more complex functions on a
:class:`~pandas.Series`.
Examples
--------
>>> idx = pd.CategoricalIndex(['a', 'b', 'c'])
>>> idx
CategoricalIndex(['a', 'b', 'c'], categories=['a', 'b', 'c'],
ordered=False, dtype='category')
>>> idx.map(lambda x: x.upper())
CategoricalIndex(['A', 'B', 'C'], categories=['A', 'B', 'C'],
ordered=False, dtype='category')
>>> idx.map({'a': 'first', 'b': 'second', 'c': 'third'})
CategoricalIndex(['first', 'second', 'third'], categories=['first',
'second', 'third'], ordered=False, dtype='category')
If the mapping is one-to-one the ordering of the categories is
preserved:
>>> idx = pd.CategoricalIndex(['a', 'b', 'c'], ordered=True)
>>> idx
CategoricalIndex(['a', 'b', 'c'], categories=['a', 'b', 'c'],
ordered=True, dtype='category')
>>> idx.map({'a': 3, 'b': 2, 'c': 1})
CategoricalIndex([3, 2, 1], categories=[3, 2, 1], ordered=True,
dtype='category')
If the mapping is not one-to-one an :class:`~pandas.Index` is returned:
>>> idx.map({'a': 'first', 'b': 'second', 'c': 'first'})
Index(['first', 'second', 'first'], dtype='object')
If a `dict` is used, all unmapped categories are mapped to `NaN` and
the result is an :class:`~pandas.Index`:
>>> idx.map({'a': 'first', 'b': 'second'})
Index(['first', 'second', nan], dtype='object')
"""
return self._shallow_copy_with_infer(self.values.map(mapper))
def delete(self, loc):
"""
Make new Index with passed location(-s) deleted
Returns
-------
new_index : Index
"""
return self._create_from_codes(np.delete(self.codes, loc))
def insert(self, loc: int, item):
"""
Make new Index inserting new item at location. Follows
Python list.append semantics for negative values
Parameters
----------
loc : int
item : object
Returns
-------
new_index : Index
Raises
------
ValueError if the item is not in the categories
"""
code = self.categories.get_indexer([item])
if (code == -1) and not (is_scalar(item) and isna(item)):
raise TypeError(
"cannot insert an item into a CategoricalIndex "
"that is not already an existing category"
)
codes = self.codes
codes = np.concatenate((codes[:loc], code, codes[loc:]))
return self._create_from_codes(codes)
def _concat(self, to_concat, name):
# if calling index is category, don't check dtype of others
return CategoricalIndex._concat_same_dtype(self, to_concat, name)
def _concat_same_dtype(self, to_concat, name):
"""
Concatenate to_concat which has the same class
ValueError if other is not in the categories
"""
codes = np.concatenate([self._is_dtype_compat(c).codes for c in to_concat])
result = self._create_from_codes(codes, name=name)
# if name is None, _create_from_codes sets self.name
result.name = name
return result
def _delegate_method(self, name: str, *args, **kwargs):
""" method delegation to the ._values """
method = getattr(self._values, name)
if "inplace" in kwargs:
raise ValueError("cannot use inplace with CategoricalIndex")
res = method(*args, **kwargs)
if is_scalar(res):
return res
return CategoricalIndex(res, name=self.name)
CategoricalIndex._add_numeric_methods_add_sub_disabled()
CategoricalIndex._add_numeric_methods_disabled()
CategoricalIndex._add_logical_methods_disabled()
from typing import Any, List
import warnings
import numpy as np
from pandas._config import get_option
from pandas._libs import index as libindex
from pandas._libs.hashtable import duplicated_int64
from pandas._libs.lib import no_default
from pandas._typing import Label
from pandas.util._decorators import Appender, cache_readonly
from pandas.core.dtypes.common import (
ensure_platform_int,
is_categorical_dtype,
is_interval_dtype,
is_list_like,
is_scalar,
)
from pandas.core.dtypes.dtypes import CategoricalDtype
from pandas.core.dtypes.missing import isna
from pandas.core import accessor
from pandas.core.algorithms import take_1d
from pandas.core.arrays.categorical import Categorical, _recode_for_categories, contains
import pandas.core.common as com
import pandas.core.indexes.base as ibase
from pandas.core.indexes.base import Index, _index_shared_docs, maybe_extract_name
from pandas.core.indexes.extension import ExtensionIndex, inherit_names
import pandas.core.missing as missing
from pandas.core.ops import get_op_result_name
_index_doc_kwargs = dict(ibase._index_doc_kwargs)
_index_doc_kwargs.update(dict(target_klass="CategoricalIndex"))
@inherit_names(
[
"argsort",
"_internal_get_values",
"tolist",
"codes",
"categories",
"ordered",
"_reverse_indexer",
"searchsorted",
"is_dtype_equal",
"min",
"max",
],
Categorical,
)
@accessor.delegate_names(
delegate=Categorical,
accessors=[
"rename_categories",
"reorder_categories",
"add_categories",
"remove_categories",
"remove_unused_categories",
"set_categories",
"as_ordered",
"as_unordered",
],
typ="method",
overwrite=True,
)
class CategoricalIndex(ExtensionIndex, accessor.PandasDelegate):
"""
Index based on an underlying :class:`Categorical`.
CategoricalIndex, like Categorical, can only take on a limited,
and usually fixed, number of possible values (`categories`). Also,
like Categorical, it might have an order, but numerical operations
(additions, divisions, ...) are not possible.
Parameters
----------
data : array-like (1-dimensional)
The values of the categorical. If `categories` are given, values not in
`categories` will be replaced with NaN.
categories : index-like, optional
The categories for the categorical. Items need to be unique.
If the categories are not given here (and also not in `dtype`), they
will be inferred from the `data`.
ordered : bool, optional
Whether or not this categorical is treated as an ordered
categorical. If not given here or in `dtype`, the resulting
categorical will be unordered.
dtype : CategoricalDtype or "category", optional
If :class:`CategoricalDtype`, cannot be used together with
`categories` or `ordered`.
.. versionadded:: 0.21.0
copy : bool, default False
Make a copy of input ndarray.
name : object, optional
Name to be stored in the index.
Attributes
----------
codes
categories
ordered
Methods
-------
rename_categories
reorder_categories
add_categories
remove_categories
remove_unused_categories
set_categories
as_ordered
as_unordered
map
Raises
------
ValueError
If the categories do not validate.
TypeError
If an explicit ``ordered=True`` is given but no `categories` and the
`values` are not sortable.
See Also
--------
Index : The base pandas Index type.
Categorical : A categorical array.
CategoricalDtype : Type for categorical data.
Notes
-----
See the `user guide
<https://pandas.pydata.org/pandas-docs/stable/user_guide/advanced.html#categoricalindex>`_
for more.
Examples
--------
>>> pd.CategoricalIndex(['a', 'b', 'c', 'a', 'b', 'c'])
CategoricalIndex(['a', 'b', 'c', 'a', 'b', 'c'], categories=['a', 'b', 'c'], ordered=False, dtype='category') # noqa
``CategoricalIndex`` can also be instantiated from a ``Categorical``:
>>> c = pd.Categorical(['a', 'b', 'c', 'a', 'b', 'c'])
>>> pd.CategoricalIndex(c)
CategoricalIndex(['a', 'b', 'c', 'a', 'b', 'c'], categories=['a', 'b', 'c'], ordered=False, dtype='category') # noqa
Ordered ``CategoricalIndex`` can have a min and max value.
>>> ci = pd.CategoricalIndex(['a','b','c','a','b','c'], ordered=True,
... categories=['c', 'b', 'a'])
>>> ci
CategoricalIndex(['a', 'b', 'c', 'a', 'b', 'c'], categories=['c', 'b', 'a'], ordered=True, dtype='category') # noqa
>>> ci.min()
'c'
"""
_typ = "categoricalindex"
codes: np.ndarray
categories: Index
_data: Categorical
@property
def _engine_type(self):
# self.codes can have dtype int8, int16, int32 or int64, so we need
# to return the corresponding engine type (libindex.Int8Engine, etc.).
return {
np.int8: libindex.Int8Engine,
np.int16: libindex.Int16Engine,
np.int32: libindex.Int32Engine,
np.int64: libindex.Int64Engine,
}[self.codes.dtype.type]
_attributes = ["name"]
# --------------------------------------------------------------------
# Constructors
def __new__(
cls, data=None, categories=None, ordered=None, dtype=None, copy=False, name=None
):
dtype = CategoricalDtype._from_values_or_dtype(data, categories, ordered, dtype)
name = maybe_extract_name(name, data, cls)
if not is_categorical_dtype(data):
# don't allow scalars
# if data is None, then categories must be provided
if is_scalar(data):
if data is not None or categories is None:
raise cls._scalar_data_error(data)
data = []
assert isinstance(dtype, CategoricalDtype), dtype
if not isinstance(data, Categorical) or data.dtype != dtype:
data = Categorical(data, dtype=dtype)
data = data.copy() if copy else data
return cls._simple_new(data, name=name)
def _create_from_codes(self, codes, dtype=None, name=None):
"""
*this is an internal non-public method*
create the correct categorical from codes
Parameters
----------
codes : new codes
dtype: CategoricalDtype, defaults to existing
name : optional name attribute, defaults to existing
Returns
-------
CategoricalIndex
"""
if dtype is None:
dtype = self.dtype
if name is None:
name = self.name
cat = Categorical.from_codes(codes, dtype=dtype)
return CategoricalIndex(cat, name=name)
@classmethod
def _simple_new(cls, values: Categorical, name: Label = None):
assert isinstance(values, Categorical), type(values)
result = object.__new__(cls)
result._data = values
result.name = name
result._reset_identity()
result._no_setting_name = False
return result
# --------------------------------------------------------------------
@Appender(Index._shallow_copy.__doc__)
def _shallow_copy(self, values=None, name: Label = no_default):
name = self.name if name is no_default else name
if values is None:
values = self.values
cat = Categorical(values, dtype=self.dtype)
return type(self)._simple_new(cat, name=name)
def _is_dtype_compat(self, other) -> bool:
"""
*this is an internal non-public method*
provide a comparison between the dtype of self and other (coercing if
needed)
Raises
------
TypeError if the dtypes are not compatible
"""
if is_categorical_dtype(other):
if isinstance(other, CategoricalIndex):
other = other._values
if not other.is_dtype_equal(self):
raise TypeError(
"categories must match existing categories when appending"
)
else:
values = other
if not is_list_like(values):
values = [values]
cat = Categorical(other, dtype=self.dtype)
other = CategoricalIndex(cat)
if not other.isin(values).all():
raise TypeError(
"cannot append a non-category item to a CategoricalIndex"
)
return other
def equals(self, other) -> bool:
"""
Determine if two CategoricalIndex objects contain the same elements.
Returns
-------
bool
If two CategoricalIndex objects have equal elements True,
otherwise False.
"""
if self.is_(other):
return True
if not isinstance(other, Index):
return False
try:
other = self._is_dtype_compat(other)
if isinstance(other, type(self)):
other = other._data
return self._data.equals(other)
except (TypeError, ValueError):
pass
return False
# --------------------------------------------------------------------
# Rendering Methods
@property
def _formatter_func(self):
return self.categories._formatter_func
def _format_attrs(self):
"""
Return a list of tuples of the (attr,formatted_value)
"""
max_categories = (
10
if get_option("display.max_categories") == 0
else get_option("display.max_categories")
)
attrs = [
(
"categories",
ibase.default_pprint(self.categories, max_seq_items=max_categories),
),
("ordered", self.ordered),
]
if self.name is not None:
attrs.append(("name", ibase.default_pprint(self.name)))
attrs.append(("dtype", f"'{self.dtype.name}'"))
max_seq_items = get_option("display.max_seq_items") or len(self)
if len(self) > max_seq_items:
attrs.append(("length", len(self)))
return attrs
# --------------------------------------------------------------------
@property
def inferred_type(self) -> str:
return "categorical"
@property
def values(self):
""" return the underlying data, which is a Categorical """
return self._data
@property
def _has_complex_internals(self) -> bool:
# used to avoid libreduction code paths, which raise or require conversion
return True
@Appender(Index.__contains__.__doc__)
def __contains__(self, key: Any) -> bool:
# if key is a NaN, check if any NaN is in self.
if is_scalar(key) and isna(key):
return self.hasnans
hash(key)
return contains(self, key, container=self._engine)
def __array__(self, dtype=None) -> np.ndarray:
""" the array interface, return my values """
return np.array(self._data, dtype=dtype)
@Appender(Index.astype.__doc__)
def astype(self, dtype, copy=True):
if is_interval_dtype(dtype):
from pandas import IntervalIndex
return IntervalIndex(np.array(self))
elif is_categorical_dtype(dtype):
# GH 18630
dtype = self.dtype.update_dtype(dtype)
if dtype == self.dtype:
return self.copy() if copy else self
return Index.astype(self, dtype=dtype, copy=copy)
@cache_readonly
def _isnan(self):
""" return if each value is nan"""
return self._data.codes == -1
@Appender(Index.fillna.__doc__)
def fillna(self, value, downcast=None):
self._assert_can_do_op(value)
return CategoricalIndex(self._data.fillna(value), name=self.name)
@cache_readonly
def _engine(self):
# we are going to look things up with the codes themselves.
# To avoid a reference cycle, bind `codes` to a local variable, so
# `self` is not passed into the lambda.
codes = self.codes
return self._engine_type(lambda: codes, len(self))
@Appender(Index.unique.__doc__)
def unique(self, level=None):
if level is not None:
self._validate_index_level(level)
result = self.values.unique()
# Use _simple_new instead of _shallow_copy to ensure we keep dtype
# of result, not self.
return type(self)._simple_new(result, name=self.name)
@Appender(Index.duplicated.__doc__)
def duplicated(self, keep="first"):
codes = self.codes.astype("i8")
return duplicated_int64(codes, keep)
def _to_safe_for_reshape(self):
""" convert to object if we are a categorical """
return self.astype("object")
def _maybe_cast_indexer(self, key):
code = self.categories.get_loc(key)
code = self.codes.dtype.type(code)
return code
@Appender(Index.where.__doc__)
def where(self, cond, other=None):
# TODO: Investigate an alternative implementation with
# 1. copy the underlying Categorical
# 2. setitem with `cond` and `other`
# 3. Rebuild CategoricalIndex.
if other is None:
other = self._na_value
values = np.where(cond, self.values, other)
cat = Categorical(values, dtype=self.dtype)
return type(self)._simple_new(cat, name=self.name)
def reindex(self, target, method=None, level=None, limit=None, tolerance=None):
"""
Create index with target's values (move/add/delete values as necessary)
Returns
-------
new_index : pd.Index
Resulting index
indexer : np.ndarray or None
Indices of output values in original index
"""
if method is not None:
raise NotImplementedError(
"argument method is not implemented for CategoricalIndex.reindex"
)
if level is not None:
raise NotImplementedError(
"argument level is not implemented for CategoricalIndex.reindex"
)
if limit is not None:
raise NotImplementedError(
"argument limit is not implemented for CategoricalIndex.reindex"
)
target = ibase.ensure_index(target)
missing: List[int]
if self.equals(target):
indexer = None
missing = []
else:
indexer, missing = self.get_indexer_non_unique(np.array(target))
if len(self.codes) and indexer is not None:
new_target = self.take(indexer)
else:
new_target = target
# filling in missing if needed
if len(missing):
cats = self.categories.get_indexer(target)
if (cats == -1).any():
# coerce to a regular index here!
result = Index(np.array(self), name=self.name)
new_target, indexer, _ = result._reindex_non_unique(np.array(target))
else:
codes = new_target.codes.copy()
codes[indexer == -1] = cats[missing]
new_target = self._create_from_codes(codes)
# we always want to return an Index type here
# to be consistent with .reindex for other index types (e.g. they don't
# coerce based on the actual values, only on the dtype)
# unless we had an initial Categorical to begin with
# in which case we are going to conform to the passed Categorical
new_target = np.asarray(new_target)
if is_categorical_dtype(target):
new_target = target._shallow_copy(new_target, name=self.name)
else:
new_target = Index(new_target, name=self.name)
return new_target, indexer
def _reindex_non_unique(self, target):
"""
reindex from a non-unique; which CategoricalIndex's are almost
always
"""
new_target, indexer = self.reindex(target)
new_indexer = None
check = indexer == -1
if check.any():
new_indexer = np.arange(len(self.take(indexer)))
new_indexer[check] = -1
cats = self.categories.get_indexer(target)
if not (cats == -1).any():
# .reindex returns normal Index. Revert to CategoricalIndex if
# all targets are included in my categories
new_target = self._shallow_copy(new_target)
return new_target, indexer, new_indexer
@Appender(_index_shared_docs["get_indexer"] % _index_doc_kwargs)
def get_indexer(self, target, method=None, limit=None, tolerance=None):
method = missing.clean_reindex_fill_method(method)
target = ibase.ensure_index(target)
if self.is_unique and self.equals(target):
return np.arange(len(self), dtype="intp")
if method == "pad" or method == "backfill":
raise NotImplementedError(
"method='pad' and method='backfill' not "
"implemented yet for CategoricalIndex"
)
elif method == "nearest":
raise NotImplementedError(
"method='nearest' not implemented yet for CategoricalIndex"
)
if isinstance(target, CategoricalIndex) and self.values.is_dtype_equal(target):
if self.values.equals(target.values):
# we have the same codes
codes = target.codes
else:
codes = _recode_for_categories(
target.codes, target.categories, self.values.categories
)
else:
if isinstance(target, CategoricalIndex):
code_indexer = self.categories.get_indexer(target.categories)
codes = take_1d(code_indexer, target.codes, fill_value=-1)
else:
codes = self.categories.get_indexer(target)
indexer, _ = self._engine.get_indexer_non_unique(codes)
return ensure_platform_int(indexer)
@Appender(_index_shared_docs["get_indexer_non_unique"] % _index_doc_kwargs)
def get_indexer_non_unique(self, target):
target = ibase.ensure_index(target)
if isinstance(target, CategoricalIndex):
# Indexing on codes is more efficient if categories are the same:
if target.categories is self.categories:
target = target.codes
indexer, missing = self._engine.get_indexer_non_unique(target)
return ensure_platform_int(indexer), missing
target = target.values
codes = self.categories.get_indexer(target)
indexer, missing = self._engine.get_indexer_non_unique(codes)
return ensure_platform_int(indexer), missing
@Appender(Index._convert_scalar_indexer.__doc__)
def _convert_scalar_indexer(self, key, kind: str):
assert kind in ["loc", "getitem"]
if kind == "loc":
try:
return self.categories._convert_scalar_indexer(key, kind="loc")
except TypeError:
self._invalid_indexer("label", key)
return super()._convert_scalar_indexer(key, kind=kind)
@Appender(Index._convert_list_indexer.__doc__)
def _convert_list_indexer(self, keyarr):
# Return our indexer or raise if all of the values are not included in
# the categories
if self.categories._defer_to_indexing:
indexer = self.categories._convert_list_indexer(keyarr)
return Index(self.codes).get_indexer_for(indexer)
indexer = self.categories.get_indexer(np.asarray(keyarr))
if (indexer == -1).any():
raise KeyError(
"a list-indexer must only include values that are in the categories"
)
return self.get_indexer(keyarr)
@Appender(Index._convert_arr_indexer.__doc__)
def _convert_arr_indexer(self, keyarr):
keyarr = com.asarray_tuplesafe(keyarr)
if self.categories._defer_to_indexing:
return keyarr
return self._shallow_copy(keyarr)
@Appender(Index._convert_index_indexer.__doc__)
def _convert_index_indexer(self, keyarr):
return self._shallow_copy(keyarr)
def take_nd(self, *args, **kwargs):
"""Alias for `take`"""
warnings.warn(
"CategoricalIndex.take_nd is deprecated, use CategoricalIndex.take instead",
FutureWarning,
stacklevel=2,
)
return self.take(*args, **kwargs)
@Appender(Index._maybe_cast_slice_bound.__doc__)
def _maybe_cast_slice_bound(self, label, side, kind):
if kind == "loc":
return label
return super()._maybe_cast_slice_bound(label, side, kind)
def map(self, mapper):
"""
Map values using input correspondence (a dict, Series, or function).
Maps the values (their categories, not the codes) of the index to new
categories. If the mapping correspondence is one-to-one the result is a
:class:`~pandas.CategoricalIndex` which has the same order property as
the original, otherwise an :class:`~pandas.Index` is returned.
If a `dict` or :class:`~pandas.Series` is used any unmapped category is
mapped to `NaN`. Note that if this happens an :class:`~pandas.Index`
will be returned.
Parameters
----------
mapper : function, dict, or Series
Mapping correspondence.
Returns
-------
pandas.CategoricalIndex or pandas.Index
Mapped index.
See Also
--------
Index.map : Apply a mapping correspondence on an
:class:`~pandas.Index`.
Series.map : Apply a mapping correspondence on a
:class:`~pandas.Series`.
Series.apply : Apply more complex functions on a
:class:`~pandas.Series`.
Examples
--------
>>> idx = pd.CategoricalIndex(['a', 'b', 'c'])
>>> idx
CategoricalIndex(['a', 'b', 'c'], categories=['a', 'b', 'c'],
ordered=False, dtype='category')
>>> idx.map(lambda x: x.upper())
CategoricalIndex(['A', 'B', 'C'], categories=['A', 'B', 'C'],
ordered=False, dtype='category')
>>> idx.map({'a': 'first', 'b': 'second', 'c': 'third'})
CategoricalIndex(['first', 'second', 'third'], categories=['first',
'second', 'third'], ordered=False, dtype='category')
If the mapping is one-to-one the ordering of the categories is
preserved:
>>> idx = pd.CategoricalIndex(['a', 'b', 'c'], ordered=True)
>>> idx
CategoricalIndex(['a', 'b', 'c'], categories=['a', 'b', 'c'],
ordered=True, dtype='category')
>>> idx.map({'a': 3, 'b': 2, 'c': 1})
CategoricalIndex([3, 2, 1], categories=[3, 2, 1], ordered=True,
dtype='category')
If the mapping is not one-to-one an :class:`~pandas.Index` is returned:
>>> idx.map({'a': 'first', 'b': 'second', 'c': 'first'})
Index(['first', 'second', 'first'], dtype='object')
If a `dict` is used, all unmapped categories are mapped to `NaN` and
the result is an :class:`~pandas.Index`:
>>> idx.map({'a': 'first', 'b': 'second'})
Index(['first', 'second', nan], dtype='object')
"""
return self._shallow_copy_with_infer(self.values.map(mapper))
def delete(self, loc):
"""
Make new Index with passed location(-s) deleted
Returns
-------
new_index : Index
"""
return self._create_from_codes(np.delete(self.codes, loc))
def insert(self, loc: int, item):
"""
Make new Index inserting new item at location. Follows
Python list.append semantics for negative values
Parameters
----------
loc : int
item : object
Returns
-------
new_index : Index
Raises
------
ValueError if the item is not in the categories
"""
code = self.categories.get_indexer([item])
if (code == -1) and not (is_scalar(item) and isna(item)):
raise TypeError(
"cannot insert an item into a CategoricalIndex "
"that is not already an existing category"
)
codes = self.codes
codes = np.concatenate((codes[:loc], code, codes[loc:]))
return self._create_from_codes(codes)
def _concat(self, to_concat, name):
# if calling index is category, don't check dtype of others
return CategoricalIndex._concat_same_dtype(self, to_concat, name)
def _concat_same_dtype(self, to_concat, name):
"""
Concatenate to_concat which has the same class
ValueError if other is not in the categories
"""
codes = np.concatenate([self._is_dtype_compat(c).codes for c in to_concat])
result = self._create_from_codes(codes, name=name)
# if name is None, _create_from_codes sets self.name
result.name = name
return result
def _delegate_method(self, name: str, *args, **kwargs):
""" method delegation to the ._values """
method = getattr(self._values, name)
if "inplace" in kwargs:
raise ValueError("cannot use inplace with CategoricalIndex")
res = method(*args, **kwargs)
if is_scalar(res):
return res
return CategoricalIndex(res, name=self.name)
def _wrap_joined_index(
self, joined: np.ndarray, other: "CategoricalIndex"
) -> "CategoricalIndex":
name = get_op_result_name(self, other)
return self._create_from_codes(joined, name=name)
CategoricalIndex._add_numeric_methods_add_sub_disabled()
CategoricalIndex._add_numeric_methods_disabled()
CategoricalIndex._add_logical_methods_disabled()
| BugsInPy/BugsInPy/temp/projects/pandas/bug-51-fixed/pandas/pandas/core/indexes/category.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-51-buggy/pandas/pandas/core/indexes/category.py |
pandas-bug-118 | import re
from typing import List
import numpy as np
from pandas.util._decorators import Appender
from pandas.core.dtypes.common import is_extension_array_dtype, is_list_like
from pandas.core.dtypes.concat import concat_compat
from pandas.core.dtypes.generic import ABCMultiIndex
from pandas.core.dtypes.missing import notna
from pandas.core.arrays import Categorical
from pandas.core.frame import DataFrame, _shared_docs
from pandas.core.indexes.base import Index
from pandas.core.reshape.concat import concat
from pandas.core.tools.numeric import to_numeric
@Appender(
_shared_docs["melt"]
% dict(caller="pd.melt(df, ", versionadded="", other="DataFrame.melt")
)
def melt(
frame: DataFrame,
id_vars=None,
value_vars=None,
var_name=None,
value_name="value",
col_level=None,
) -> DataFrame:
# TODO: what about the existing index?
# If multiindex, gather names of columns on all level for checking presence
# of `id_vars` and `value_vars`
if isinstance(frame.columns, ABCMultiIndex):
cols = [x for c in frame.columns for x in c]
else:
cols = list(frame.columns)
if id_vars is not None:
if not is_list_like(id_vars):
id_vars = [id_vars]
elif isinstance(frame.columns, ABCMultiIndex) and not isinstance(id_vars, list):
raise ValueError(
"id_vars must be a list of tuples when columns are a MultiIndex"
)
else:
# Check that `id_vars` are in frame
id_vars = list(id_vars)
missing = Index(np.ravel(id_vars)).difference(cols)
if not missing.empty:
raise KeyError(
"The following 'id_vars' are not present"
" in the DataFrame: {missing}"
"".format(missing=list(missing))
)
else:
id_vars = []
if value_vars is not None:
if not is_list_like(value_vars):
value_vars = [value_vars]
elif isinstance(frame.columns, ABCMultiIndex) and not isinstance(
value_vars, list
):
raise ValueError(
"value_vars must be a list of tuples when columns are a MultiIndex"
)
else:
value_vars = list(value_vars)
# Check that `value_vars` are in frame
missing = Index(np.ravel(value_vars)).difference(cols)
if not missing.empty:
raise KeyError(
"The following 'value_vars' are not present in"
" the DataFrame: {missing}"
"".format(missing=list(missing))
)
frame = frame.loc[:, id_vars + value_vars]
else:
frame = frame.copy()
if col_level is not None: # allow list or other?
# frame is a copy
frame.columns = frame.columns.get_level_values(col_level)
if var_name is None:
if isinstance(frame.columns, ABCMultiIndex):
if len(frame.columns.names) == len(set(frame.columns.names)):
var_name = frame.columns.names
else:
var_name = [
"variable_{i}".format(i=i) for i in range(len(frame.columns.names))
]
else:
var_name = [
frame.columns.name if frame.columns.name is not None else "variable"
]
if isinstance(var_name, str):
var_name = [var_name]
N, K = frame.shape
K -= len(id_vars)
mdata = {}
for col in id_vars:
id_data = frame.pop(col)
if is_extension_array_dtype(id_data):
id_data = concat([id_data] * K, ignore_index=True)
else:
id_data = np.tile(id_data.values, K)
mdata[col] = id_data
mcolumns = id_vars + var_name + [value_name]
mdata[value_name] = frame.values.ravel("F")
for i, col in enumerate(var_name):
# asanyarray will keep the columns as an Index
mdata[col] = np.asanyarray(frame.columns._get_level_values(i)).repeat(N)
return frame._constructor(mdata, columns=mcolumns)
def lreshape(data: DataFrame, groups, dropna: bool = True, label=None) -> DataFrame:
"""
Reshape long-format data to wide. Generalized inverse of DataFrame.pivot
Parameters
----------
data : DataFrame
groups : dict
{new_name : list_of_columns}
dropna : boolean, default True
label : object, default None
Dummy kwarg, not used.
Examples
--------
>>> data = pd.DataFrame({'hr1': [514, 573], 'hr2': [545, 526],
... 'team': ['Red Sox', 'Yankees'],
... 'year1': [2007, 2007], 'year2': [2008, 2008]})
>>> data
hr1 hr2 team year1 year2
0 514 545 Red Sox 2007 2008
1 573 526 Yankees 2007 2008
>>> pd.lreshape(data, {'year': ['year1', 'year2'], 'hr': ['hr1', 'hr2']})
team year hr
0 Red Sox 2007 514
1 Yankees 2007 573
2 Red Sox 2008 545
3 Yankees 2008 526
Returns
-------
reshaped : DataFrame
"""
if isinstance(groups, dict):
keys = list(groups.keys())
values = list(groups.values())
else:
keys, values = zip(*groups)
all_cols = list(set.union(*[set(x) for x in values]))
id_cols = list(data.columns.difference(all_cols))
K = len(values[0])
for seq in values:
if len(seq) != K:
raise ValueError("All column lists must be same length")
mdata = {}
pivot_cols = []
for target, names in zip(keys, values):
to_concat = [data[col].values for col in names]
mdata[target] = concat_compat(to_concat)
pivot_cols.append(target)
for col in id_cols:
mdata[col] = np.tile(data[col].values, K)
if dropna:
mask = np.ones(len(mdata[pivot_cols[0]]), dtype=bool)
for c in pivot_cols:
mask &= notna(mdata[c])
if not mask.all():
mdata = {k: v[mask] for k, v in mdata.items()}
return data._constructor(mdata, columns=id_cols + pivot_cols)
def wide_to_long(df: DataFrame, stubnames, i, j, sep: str = "", suffix: str = r"\d+"):
r"""
Wide panel to long format. Less flexible but more user-friendly than melt.
With stubnames ['A', 'B'], this function expects to find one or more
group of columns with format
A-suffix1, A-suffix2,..., B-suffix1, B-suffix2,...
You specify what you want to call this suffix in the resulting long format
with `j` (for example `j='year'`)
Each row of these wide variables are assumed to be uniquely identified by
`i` (can be a single column name or a list of column names)
All remaining variables in the data frame are left intact.
Parameters
----------
df : DataFrame
The wide-format DataFrame.
stubnames : str or list-like
The stub name(s). The wide format variables are assumed to
start with the stub names.
i : str or list-like
Column(s) to use as id variable(s).
j : str
The name of the sub-observation variable. What you wish to name your
suffix in the long format.
sep : str, default ""
A character indicating the separation of the variable names
in the wide format, to be stripped from the names in the long format.
For example, if your column names are A-suffix1, A-suffix2, you
can strip the hyphen by specifying `sep='-'`.
suffix : str, default '\\d+'
A regular expression capturing the wanted suffixes. '\\d+' captures
numeric suffixes. Suffixes with no numbers could be specified with the
negated character class '\\D+'. You can also further disambiguate
suffixes, for example, if your wide variables are of the form
A-one, B-two,.., and you have an unrelated column A-rating, you can
ignore the last one by specifying `suffix='(!?one|two)'`.
.. versionchanged:: 0.23.0
When all suffixes are numeric, they are cast to int64/float64.
Returns
-------
DataFrame
A DataFrame that contains each stub name as a variable, with new index
(i, j).
Notes
-----
All extra variables are left untouched. This simply uses
`pandas.melt` under the hood, but is hard-coded to "do the right thing"
in a typical case.
Examples
--------
>>> np.random.seed(123)
>>> df = pd.DataFrame({"A1970" : {0 : "a", 1 : "b", 2 : "c"},
... "A1980" : {0 : "d", 1 : "e", 2 : "f"},
... "B1970" : {0 : 2.5, 1 : 1.2, 2 : .7},
... "B1980" : {0 : 3.2, 1 : 1.3, 2 : .1},
... "X" : dict(zip(range(3), np.random.randn(3)))
... })
>>> df["id"] = df.index
>>> df
A1970 A1980 B1970 B1980 X id
0 a d 2.5 3.2 -1.085631 0
1 b e 1.2 1.3 0.997345 1
2 c f 0.7 0.1 0.282978 2
>>> pd.wide_to_long(df, ["A", "B"], i="id", j="year")
... # doctest: +NORMALIZE_WHITESPACE
X A B
id year
0 1970 -1.085631 a 2.5
1 1970 0.997345 b 1.2
2 1970 0.282978 c 0.7
0 1980 -1.085631 d 3.2
1 1980 0.997345 e 1.3
2 1980 0.282978 f 0.1
With multiple id columns
>>> df = pd.DataFrame({
... 'famid': [1, 1, 1, 2, 2, 2, 3, 3, 3],
... 'birth': [1, 2, 3, 1, 2, 3, 1, 2, 3],
... 'ht1': [2.8, 2.9, 2.2, 2, 1.8, 1.9, 2.2, 2.3, 2.1],
... 'ht2': [3.4, 3.8, 2.9, 3.2, 2.8, 2.4, 3.3, 3.4, 2.9]
... })
>>> df
famid birth ht1 ht2
0 1 1 2.8 3.4
1 1 2 2.9 3.8
2 1 3 2.2 2.9
3 2 1 2.0 3.2
4 2 2 1.8 2.8
5 2 3 1.9 2.4
6 3 1 2.2 3.3
7 3 2 2.3 3.4
8 3 3 2.1 2.9
>>> l = pd.wide_to_long(df, stubnames='ht', i=['famid', 'birth'], j='age')
>>> l
... # doctest: +NORMALIZE_WHITESPACE
ht
famid birth age
1 1 1 2.8
2 3.4
2 1 2.9
2 3.8
3 1 2.2
2 2.9
2 1 1 2.0
2 3.2
2 1 1.8
2 2.8
3 1 1.9
2 2.4
3 1 1 2.2
2 3.3
2 1 2.3
2 3.4
3 1 2.1
2 2.9
Going from long back to wide just takes some creative use of `unstack`
>>> w = l.unstack()
>>> w.columns = w.columns.map('{0[0]}{0[1]}'.format)
>>> w.reset_index()
famid birth ht1 ht2
0 1 1 2.8 3.4
1 1 2 2.9 3.8
2 1 3 2.2 2.9
3 2 1 2.0 3.2
4 2 2 1.8 2.8
5 2 3 1.9 2.4
6 3 1 2.2 3.3
7 3 2 2.3 3.4
8 3 3 2.1 2.9
Less wieldy column names are also handled
>>> np.random.seed(0)
>>> df = pd.DataFrame({'A(weekly)-2010': np.random.rand(3),
... 'A(weekly)-2011': np.random.rand(3),
... 'B(weekly)-2010': np.random.rand(3),
... 'B(weekly)-2011': np.random.rand(3),
... 'X' : np.random.randint(3, size=3)})
>>> df['id'] = df.index
>>> df # doctest: +NORMALIZE_WHITESPACE, +ELLIPSIS
A(weekly)-2010 A(weekly)-2011 B(weekly)-2010 B(weekly)-2011 X id
0 0.548814 0.544883 0.437587 0.383442 0 0
1 0.715189 0.423655 0.891773 0.791725 1 1
2 0.602763 0.645894 0.963663 0.528895 1 2
>>> pd.wide_to_long(df, ['A(weekly)', 'B(weekly)'], i='id',
... j='year', sep='-')
... # doctest: +NORMALIZE_WHITESPACE
X A(weekly) B(weekly)
id year
0 2010 0 0.548814 0.437587
1 2010 1 0.715189 0.891773
2 2010 1 0.602763 0.963663
0 2011 0 0.544883 0.383442
1 2011 1 0.423655 0.791725
2 2011 1 0.645894 0.528895
If we have many columns, we could also use a regex to find our
stubnames and pass that list on to wide_to_long
>>> stubnames = sorted(
... set([match[0] for match in df.columns.str.findall(
... r'[A-B]\(.*\)').values if match != []])
... )
>>> list(stubnames)
['A(weekly)', 'B(weekly)']
All of the above examples have integers as suffixes. It is possible to
have non-integers as suffixes.
>>> df = pd.DataFrame({
... 'famid': [1, 1, 1, 2, 2, 2, 3, 3, 3],
... 'birth': [1, 2, 3, 1, 2, 3, 1, 2, 3],
... 'ht_one': [2.8, 2.9, 2.2, 2, 1.8, 1.9, 2.2, 2.3, 2.1],
... 'ht_two': [3.4, 3.8, 2.9, 3.2, 2.8, 2.4, 3.3, 3.4, 2.9]
... })
>>> df
famid birth ht_one ht_two
0 1 1 2.8 3.4
1 1 2 2.9 3.8
2 1 3 2.2 2.9
3 2 1 2.0 3.2
4 2 2 1.8 2.8
5 2 3 1.9 2.4
6 3 1 2.2 3.3
7 3 2 2.3 3.4
8 3 3 2.1 2.9
>>> l = pd.wide_to_long(df, stubnames='ht', i=['famid', 'birth'], j='age',
... sep='_', suffix='\w+')
>>> l
... # doctest: +NORMALIZE_WHITESPACE
ht
famid birth age
1 1 one 2.8
two 3.4
2 one 2.9
two 3.8
3 one 2.2
two 2.9
2 1 one 2.0
two 3.2
2 one 1.8
two 2.8
3 one 1.9
two 2.4
3 1 one 2.2
two 3.3
2 one 2.3
two 3.4
3 one 2.1
two 2.9
"""
def get_var_names(df, stub: str, sep: str, suffix: str) -> List[str]:
regex = r"^{stub}{sep}{suffix}$".format(
stub=re.escape(stub), sep=re.escape(sep), suffix=suffix
)
pattern = re.compile(regex)
return [col for col in df.columns if pattern.match(col)]
def melt_stub(df, stub: str, i, j, value_vars, sep: str):
newdf = melt(
df,
id_vars=i,
value_vars=value_vars,
value_name=stub.rstrip(sep),
var_name=j,
)
newdf[j] = Categorical(newdf[j])
newdf[j] = newdf[j].str.replace(re.escape(stub + sep), "")
# GH17627 Cast numerics suffixes to int/float
newdf[j] = to_numeric(newdf[j], errors="ignore")
return newdf.set_index(i + [j])
if not is_list_like(stubnames):
stubnames = [stubnames]
else:
stubnames = list(stubnames)
if any(col in stubnames for col in df.columns):
raise ValueError("stubname can't be identical to a column name")
if not is_list_like(i):
i = [i]
else:
i = list(i)
if df[i].duplicated().any():
raise ValueError("the id variables need to uniquely identify each row")
value_vars = [get_var_names(df, stub, sep, suffix) for stub in stubnames]
value_vars_flattened = [e for sublist in value_vars for e in sublist]
id_vars = list(set(df.columns.tolist()).difference(value_vars_flattened))
_melted = [melt_stub(df, s, i, j, v, sep) for s, v in zip(stubnames, value_vars)]
melted = _melted[0].join(_melted[1:], how="outer")
if len(i) == 1:
new = df[id_vars].set_index(i).join(melted)
return new
new = df[id_vars].merge(melted.reset_index(), on=i).set_index(i + [j])
return new
import re
from typing import List
import numpy as np
from pandas.util._decorators import Appender
from pandas.core.dtypes.common import is_extension_array_dtype, is_list_like
from pandas.core.dtypes.concat import concat_compat
from pandas.core.dtypes.generic import ABCMultiIndex
from pandas.core.dtypes.missing import notna
from pandas.core.arrays import Categorical
import pandas.core.common as com
from pandas.core.frame import DataFrame, _shared_docs
from pandas.core.indexes.base import Index
from pandas.core.reshape.concat import concat
from pandas.core.tools.numeric import to_numeric
@Appender(
_shared_docs["melt"]
% dict(caller="pd.melt(df, ", versionadded="", other="DataFrame.melt")
)
def melt(
frame: DataFrame,
id_vars=None,
value_vars=None,
var_name=None,
value_name="value",
col_level=None,
) -> DataFrame:
# TODO: what about the existing index?
# If multiindex, gather names of columns on all level for checking presence
# of `id_vars` and `value_vars`
if isinstance(frame.columns, ABCMultiIndex):
cols = [x for c in frame.columns for x in c]
else:
cols = list(frame.columns)
if id_vars is not None:
if not is_list_like(id_vars):
id_vars = [id_vars]
elif isinstance(frame.columns, ABCMultiIndex) and not isinstance(id_vars, list):
raise ValueError(
"id_vars must be a list of tuples when columns are a MultiIndex"
)
else:
# Check that `id_vars` are in frame
id_vars = list(id_vars)
missing = Index(com.flatten(id_vars)).difference(cols)
if not missing.empty:
raise KeyError(
"The following 'id_vars' are not present"
" in the DataFrame: {missing}"
"".format(missing=list(missing))
)
else:
id_vars = []
if value_vars is not None:
if not is_list_like(value_vars):
value_vars = [value_vars]
elif isinstance(frame.columns, ABCMultiIndex) and not isinstance(
value_vars, list
):
raise ValueError(
"value_vars must be a list of tuples when columns are a MultiIndex"
)
else:
value_vars = list(value_vars)
# Check that `value_vars` are in frame
missing = Index(com.flatten(value_vars)).difference(cols)
if not missing.empty:
raise KeyError(
"The following 'value_vars' are not present in"
" the DataFrame: {missing}"
"".format(missing=list(missing))
)
frame = frame.loc[:, id_vars + value_vars]
else:
frame = frame.copy()
if col_level is not None: # allow list or other?
# frame is a copy
frame.columns = frame.columns.get_level_values(col_level)
if var_name is None:
if isinstance(frame.columns, ABCMultiIndex):
if len(frame.columns.names) == len(set(frame.columns.names)):
var_name = frame.columns.names
else:
var_name = [
"variable_{i}".format(i=i) for i in range(len(frame.columns.names))
]
else:
var_name = [
frame.columns.name if frame.columns.name is not None else "variable"
]
if isinstance(var_name, str):
var_name = [var_name]
N, K = frame.shape
K -= len(id_vars)
mdata = {}
for col in id_vars:
id_data = frame.pop(col)
if is_extension_array_dtype(id_data):
id_data = concat([id_data] * K, ignore_index=True)
else:
id_data = np.tile(id_data.values, K)
mdata[col] = id_data
mcolumns = id_vars + var_name + [value_name]
mdata[value_name] = frame.values.ravel("F")
for i, col in enumerate(var_name):
# asanyarray will keep the columns as an Index
mdata[col] = np.asanyarray(frame.columns._get_level_values(i)).repeat(N)
return frame._constructor(mdata, columns=mcolumns)
def lreshape(data: DataFrame, groups, dropna: bool = True, label=None) -> DataFrame:
"""
Reshape long-format data to wide. Generalized inverse of DataFrame.pivot
Parameters
----------
data : DataFrame
groups : dict
{new_name : list_of_columns}
dropna : boolean, default True
label : object, default None
Dummy kwarg, not used.
Examples
--------
>>> data = pd.DataFrame({'hr1': [514, 573], 'hr2': [545, 526],
... 'team': ['Red Sox', 'Yankees'],
... 'year1': [2007, 2007], 'year2': [2008, 2008]})
>>> data
hr1 hr2 team year1 year2
0 514 545 Red Sox 2007 2008
1 573 526 Yankees 2007 2008
>>> pd.lreshape(data, {'year': ['year1', 'year2'], 'hr': ['hr1', 'hr2']})
team year hr
0 Red Sox 2007 514
1 Yankees 2007 573
2 Red Sox 2008 545
3 Yankees 2008 526
Returns
-------
reshaped : DataFrame
"""
if isinstance(groups, dict):
keys = list(groups.keys())
values = list(groups.values())
else:
keys, values = zip(*groups)
all_cols = list(set.union(*[set(x) for x in values]))
id_cols = list(data.columns.difference(all_cols))
K = len(values[0])
for seq in values:
if len(seq) != K:
raise ValueError("All column lists must be same length")
mdata = {}
pivot_cols = []
for target, names in zip(keys, values):
to_concat = [data[col].values for col in names]
mdata[target] = concat_compat(to_concat)
pivot_cols.append(target)
for col in id_cols:
mdata[col] = np.tile(data[col].values, K)
if dropna:
mask = np.ones(len(mdata[pivot_cols[0]]), dtype=bool)
for c in pivot_cols:
mask &= notna(mdata[c])
if not mask.all():
mdata = {k: v[mask] for k, v in mdata.items()}
return data._constructor(mdata, columns=id_cols + pivot_cols)
def wide_to_long(df: DataFrame, stubnames, i, j, sep: str = "", suffix: str = r"\d+"):
r"""
Wide panel to long format. Less flexible but more user-friendly than melt.
With stubnames ['A', 'B'], this function expects to find one or more
group of columns with format
A-suffix1, A-suffix2,..., B-suffix1, B-suffix2,...
You specify what you want to call this suffix in the resulting long format
with `j` (for example `j='year'`)
Each row of these wide variables are assumed to be uniquely identified by
`i` (can be a single column name or a list of column names)
All remaining variables in the data frame are left intact.
Parameters
----------
df : DataFrame
The wide-format DataFrame.
stubnames : str or list-like
The stub name(s). The wide format variables are assumed to
start with the stub names.
i : str or list-like
Column(s) to use as id variable(s).
j : str
The name of the sub-observation variable. What you wish to name your
suffix in the long format.
sep : str, default ""
A character indicating the separation of the variable names
in the wide format, to be stripped from the names in the long format.
For example, if your column names are A-suffix1, A-suffix2, you
can strip the hyphen by specifying `sep='-'`.
suffix : str, default '\\d+'
A regular expression capturing the wanted suffixes. '\\d+' captures
numeric suffixes. Suffixes with no numbers could be specified with the
negated character class '\\D+'. You can also further disambiguate
suffixes, for example, if your wide variables are of the form
A-one, B-two,.., and you have an unrelated column A-rating, you can
ignore the last one by specifying `suffix='(!?one|two)'`.
.. versionchanged:: 0.23.0
When all suffixes are numeric, they are cast to int64/float64.
Returns
-------
DataFrame
A DataFrame that contains each stub name as a variable, with new index
(i, j).
Notes
-----
All extra variables are left untouched. This simply uses
`pandas.melt` under the hood, but is hard-coded to "do the right thing"
in a typical case.
Examples
--------
>>> np.random.seed(123)
>>> df = pd.DataFrame({"A1970" : {0 : "a", 1 : "b", 2 : "c"},
... "A1980" : {0 : "d", 1 : "e", 2 : "f"},
... "B1970" : {0 : 2.5, 1 : 1.2, 2 : .7},
... "B1980" : {0 : 3.2, 1 : 1.3, 2 : .1},
... "X" : dict(zip(range(3), np.random.randn(3)))
... })
>>> df["id"] = df.index
>>> df
A1970 A1980 B1970 B1980 X id
0 a d 2.5 3.2 -1.085631 0
1 b e 1.2 1.3 0.997345 1
2 c f 0.7 0.1 0.282978 2
>>> pd.wide_to_long(df, ["A", "B"], i="id", j="year")
... # doctest: +NORMALIZE_WHITESPACE
X A B
id year
0 1970 -1.085631 a 2.5
1 1970 0.997345 b 1.2
2 1970 0.282978 c 0.7
0 1980 -1.085631 d 3.2
1 1980 0.997345 e 1.3
2 1980 0.282978 f 0.1
With multiple id columns
>>> df = pd.DataFrame({
... 'famid': [1, 1, 1, 2, 2, 2, 3, 3, 3],
... 'birth': [1, 2, 3, 1, 2, 3, 1, 2, 3],
... 'ht1': [2.8, 2.9, 2.2, 2, 1.8, 1.9, 2.2, 2.3, 2.1],
... 'ht2': [3.4, 3.8, 2.9, 3.2, 2.8, 2.4, 3.3, 3.4, 2.9]
... })
>>> df
famid birth ht1 ht2
0 1 1 2.8 3.4
1 1 2 2.9 3.8
2 1 3 2.2 2.9
3 2 1 2.0 3.2
4 2 2 1.8 2.8
5 2 3 1.9 2.4
6 3 1 2.2 3.3
7 3 2 2.3 3.4
8 3 3 2.1 2.9
>>> l = pd.wide_to_long(df, stubnames='ht', i=['famid', 'birth'], j='age')
>>> l
... # doctest: +NORMALIZE_WHITESPACE
ht
famid birth age
1 1 1 2.8
2 3.4
2 1 2.9
2 3.8
3 1 2.2
2 2.9
2 1 1 2.0
2 3.2
2 1 1.8
2 2.8
3 1 1.9
2 2.4
3 1 1 2.2
2 3.3
2 1 2.3
2 3.4
3 1 2.1
2 2.9
Going from long back to wide just takes some creative use of `unstack`
>>> w = l.unstack()
>>> w.columns = w.columns.map('{0[0]}{0[1]}'.format)
>>> w.reset_index()
famid birth ht1 ht2
0 1 1 2.8 3.4
1 1 2 2.9 3.8
2 1 3 2.2 2.9
3 2 1 2.0 3.2
4 2 2 1.8 2.8
5 2 3 1.9 2.4
6 3 1 2.2 3.3
7 3 2 2.3 3.4
8 3 3 2.1 2.9
Less wieldy column names are also handled
>>> np.random.seed(0)
>>> df = pd.DataFrame({'A(weekly)-2010': np.random.rand(3),
... 'A(weekly)-2011': np.random.rand(3),
... 'B(weekly)-2010': np.random.rand(3),
... 'B(weekly)-2011': np.random.rand(3),
... 'X' : np.random.randint(3, size=3)})
>>> df['id'] = df.index
>>> df # doctest: +NORMALIZE_WHITESPACE, +ELLIPSIS
A(weekly)-2010 A(weekly)-2011 B(weekly)-2010 B(weekly)-2011 X id
0 0.548814 0.544883 0.437587 0.383442 0 0
1 0.715189 0.423655 0.891773 0.791725 1 1
2 0.602763 0.645894 0.963663 0.528895 1 2
>>> pd.wide_to_long(df, ['A(weekly)', 'B(weekly)'], i='id',
... j='year', sep='-')
... # doctest: +NORMALIZE_WHITESPACE
X A(weekly) B(weekly)
id year
0 2010 0 0.548814 0.437587
1 2010 1 0.715189 0.891773
2 2010 1 0.602763 0.963663
0 2011 0 0.544883 0.383442
1 2011 1 0.423655 0.791725
2 2011 1 0.645894 0.528895
If we have many columns, we could also use a regex to find our
stubnames and pass that list on to wide_to_long
>>> stubnames = sorted(
... set([match[0] for match in df.columns.str.findall(
... r'[A-B]\(.*\)').values if match != []])
... )
>>> list(stubnames)
['A(weekly)', 'B(weekly)']
All of the above examples have integers as suffixes. It is possible to
have non-integers as suffixes.
>>> df = pd.DataFrame({
... 'famid': [1, 1, 1, 2, 2, 2, 3, 3, 3],
... 'birth': [1, 2, 3, 1, 2, 3, 1, 2, 3],
... 'ht_one': [2.8, 2.9, 2.2, 2, 1.8, 1.9, 2.2, 2.3, 2.1],
... 'ht_two': [3.4, 3.8, 2.9, 3.2, 2.8, 2.4, 3.3, 3.4, 2.9]
... })
>>> df
famid birth ht_one ht_two
0 1 1 2.8 3.4
1 1 2 2.9 3.8
2 1 3 2.2 2.9
3 2 1 2.0 3.2
4 2 2 1.8 2.8
5 2 3 1.9 2.4
6 3 1 2.2 3.3
7 3 2 2.3 3.4
8 3 3 2.1 2.9
>>> l = pd.wide_to_long(df, stubnames='ht', i=['famid', 'birth'], j='age',
... sep='_', suffix='\w+')
>>> l
... # doctest: +NORMALIZE_WHITESPACE
ht
famid birth age
1 1 one 2.8
two 3.4
2 one 2.9
two 3.8
3 one 2.2
two 2.9
2 1 one 2.0
two 3.2
2 one 1.8
two 2.8
3 one 1.9
two 2.4
3 1 one 2.2
two 3.3
2 one 2.3
two 3.4
3 one 2.1
two 2.9
"""
def get_var_names(df, stub: str, sep: str, suffix: str) -> List[str]:
regex = r"^{stub}{sep}{suffix}$".format(
stub=re.escape(stub), sep=re.escape(sep), suffix=suffix
)
pattern = re.compile(regex)
return [col for col in df.columns if pattern.match(col)]
def melt_stub(df, stub: str, i, j, value_vars, sep: str):
newdf = melt(
df,
id_vars=i,
value_vars=value_vars,
value_name=stub.rstrip(sep),
var_name=j,
)
newdf[j] = Categorical(newdf[j])
newdf[j] = newdf[j].str.replace(re.escape(stub + sep), "")
# GH17627 Cast numerics suffixes to int/float
newdf[j] = to_numeric(newdf[j], errors="ignore")
return newdf.set_index(i + [j])
if not is_list_like(stubnames):
stubnames = [stubnames]
else:
stubnames = list(stubnames)
if any(col in stubnames for col in df.columns):
raise ValueError("stubname can't be identical to a column name")
if not is_list_like(i):
i = [i]
else:
i = list(i)
if df[i].duplicated().any():
raise ValueError("the id variables need to uniquely identify each row")
value_vars = [get_var_names(df, stub, sep, suffix) for stub in stubnames]
value_vars_flattened = [e for sublist in value_vars for e in sublist]
id_vars = list(set(df.columns.tolist()).difference(value_vars_flattened))
_melted = [melt_stub(df, s, i, j, v, sep) for s, v in zip(stubnames, value_vars)]
melted = _melted[0].join(_melted[1:], how="outer")
if len(i) == 1:
new = df[id_vars].set_index(i).join(melted)
return new
new = df[id_vars].merge(melted.reset_index(), on=i).set_index(i + [j])
return new
| BugsInPy/BugsInPy/temp/projects/pandas/bug-118-fixed/pandas/pandas/core/reshape/melt.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-118-buggy/pandas/pandas/core/reshape/melt.py |
pandas-bug-50 | import operator
from shutil import get_terminal_size
from typing import Dict, Hashable, List, Type, Union, cast
from warnings import warn
import numpy as np
from pandas._config import get_option
from pandas._libs import algos as libalgos, hashtable as htable
from pandas._typing import ArrayLike, Dtype, Ordered, Scalar
from pandas.compat.numpy import function as nv
from pandas.util._decorators import (
Appender,
Substitution,
cache_readonly,
deprecate_kwarg,
)
from pandas.util._validators import validate_bool_kwarg, validate_fillna_kwargs
from pandas.core.dtypes.cast import coerce_indexer_dtype, maybe_infer_to_datetimelike
from pandas.core.dtypes.common import (
ensure_int64,
ensure_object,
ensure_platform_int,
is_categorical_dtype,
is_datetime64_dtype,
is_dict_like,
is_dtype_equal,
is_extension_array_dtype,
is_integer_dtype,
is_iterator,
is_list_like,
is_object_dtype,
is_scalar,
is_sequence,
is_timedelta64_dtype,
needs_i8_conversion,
)
from pandas.core.dtypes.dtypes import CategoricalDtype
from pandas.core.dtypes.generic import ABCIndexClass, ABCSeries
from pandas.core.dtypes.inference import is_hashable
from pandas.core.dtypes.missing import isna, notna
from pandas.core import ops
from pandas.core.accessor import PandasDelegate, delegate_names
import pandas.core.algorithms as algorithms
from pandas.core.algorithms import _get_data_algo, factorize, take, take_1d, unique1d
from pandas.core.arrays.base import (
ExtensionArray,
_extension_array_shared_docs,
try_cast_to_ea,
)
from pandas.core.base import NoNewAttributesMixin, PandasObject, _shared_docs
import pandas.core.common as com
from pandas.core.construction import array, extract_array, sanitize_array
from pandas.core.indexers import check_array_indexer, deprecate_ndim_indexing
from pandas.core.missing import interpolate_2d
from pandas.core.ops.common import unpack_zerodim_and_defer
from pandas.core.sorting import nargsort
from pandas.io.formats import console
def _cat_compare_op(op):
opname = f"__{op.__name__}__"
@unpack_zerodim_and_defer(opname)
def func(self, other):
if is_list_like(other) and len(other) != len(self):
# TODO: Could this fail if the categories are listlike objects?
raise ValueError("Lengths must match.")
if not self.ordered:
if opname in ["__lt__", "__gt__", "__le__", "__ge__"]:
raise TypeError(
"Unordered Categoricals can only compare equality or not"
)
if isinstance(other, Categorical):
# Two Categoricals can only be be compared if the categories are
# the same (maybe up to ordering, depending on ordered)
msg = "Categoricals can only be compared if 'categories' are the same."
if len(self.categories) != len(other.categories):
raise TypeError(msg + " Categories are different lengths")
elif self.ordered and not (self.categories == other.categories).all():
raise TypeError(msg)
elif not set(self.categories) == set(other.categories):
raise TypeError(msg)
if not (self.ordered == other.ordered):
raise TypeError(
"Categoricals can only be compared if 'ordered' is the same"
)
if not self.ordered and not self.categories.equals(other.categories):
# both unordered and different order
other_codes = _get_codes_for_values(other, self.categories)
else:
other_codes = other._codes
f = getattr(self._codes, opname)
ret = f(other_codes)
mask = (self._codes == -1) | (other_codes == -1)
if mask.any():
# In other series, the leads to False, so do that here too
ret[mask] = False
return ret
if is_scalar(other):
if other in self.categories:
i = self.categories.get_loc(other)
ret = getattr(self._codes, opname)(i)
if opname not in {"__eq__", "__ge__", "__gt__"}:
# check for NaN needed if we are not equal or larger
mask = self._codes == -1
ret[mask] = False
return ret
else:
if opname == "__eq__":
return np.zeros(len(self), dtype=bool)
elif opname == "__ne__":
return np.ones(len(self), dtype=bool)
else:
raise TypeError(
f"Cannot compare a Categorical for op {opname} with a "
"scalar, which is not a category."
)
else:
# allow categorical vs object dtype array comparisons for equality
# these are only positional comparisons
if opname in ["__eq__", "__ne__"]:
return getattr(np.array(self), opname)(np.array(other))
raise TypeError(
f"Cannot compare a Categorical for op {opname} with "
f"type {type(other)}.\nIf you want to compare values, "
"use 'np.asarray(cat) <op> other'."
)
func.__name__ = opname
return func
def contains(cat, key, container):
"""
Helper for membership check for ``key`` in ``cat``.
This is a helper method for :method:`__contains__`
and :class:`CategoricalIndex.__contains__`.
Returns True if ``key`` is in ``cat.categories`` and the
location of ``key`` in ``categories`` is in ``container``.
Parameters
----------
cat : :class:`Categorical`or :class:`categoricalIndex`
key : a hashable object
The key to check membership for.
container : Container (e.g. list-like or mapping)
The container to check for membership in.
Returns
-------
is_in : bool
True if ``key`` is in ``self.categories`` and location of
``key`` in ``categories`` is in ``container``, else False.
Notes
-----
This method does not check for NaN values. Do that separately
before calling this method.
"""
hash(key)
# get location of key in categories.
# If a KeyError, the key isn't in categories, so logically
# can't be in container either.
try:
loc = cat.categories.get_loc(key)
except (KeyError, TypeError):
return False
# loc is the location of key in categories, but also the *value*
# for key in container. So, `key` may be in categories,
# but still not in `container`. Example ('b' in categories,
# but not in values):
# 'b' in Categorical(['a'], categories=['a', 'b']) # False
if is_scalar(loc):
return loc in container
else:
# if categories is an IntervalIndex, loc is an array.
return any(loc_ in container for loc_ in loc)
_codes_doc = """
The category codes of this categorical.
Level codes are an array if integer which are the positions of the real
values in the categories array.
There is not setter, use the other categorical methods and the normal item
setter to change values in the categorical.
"""
class Categorical(ExtensionArray, PandasObject):
"""
Represent a categorical variable in classic R / S-plus fashion.
`Categoricals` can only take on only a limited, and usually fixed, number
of possible values (`categories`). In contrast to statistical categorical
variables, a `Categorical` might have an order, but numerical operations
(additions, divisions, ...) are not possible.
All values of the `Categorical` are either in `categories` or `np.nan`.
Assigning values outside of `categories` will raise a `ValueError`. Order
is defined by the order of the `categories`, not lexical order of the
values.
Parameters
----------
values : list-like
The values of the categorical. If categories are given, values not in
categories will be replaced with NaN.
categories : Index-like (unique), optional
The unique categories for this categorical. If not given, the
categories are assumed to be the unique values of `values` (sorted, if
possible, otherwise in the order in which they appear).
ordered : bool, default False
Whether or not this categorical is treated as a ordered categorical.
If True, the resulting categorical will be ordered.
An ordered categorical respects, when sorted, the order of its
`categories` attribute (which in turn is the `categories` argument, if
provided).
dtype : CategoricalDtype
An instance of ``CategoricalDtype`` to use for this categorical.
.. versionadded:: 0.21.0
Attributes
----------
categories : Index
The categories of this categorical
codes : ndarray
The codes (integer positions, which point to the categories) of this
categorical, read only.
ordered : bool
Whether or not this Categorical is ordered.
dtype : CategoricalDtype
The instance of ``CategoricalDtype`` storing the ``categories``
and ``ordered``.
.. versionadded:: 0.21.0
Methods
-------
from_codes
__array__
Raises
------
ValueError
If the categories do not validate.
TypeError
If an explicit ``ordered=True`` is given but no `categories` and the
`values` are not sortable.
See Also
--------
CategoricalDtype : Type for categorical data.
CategoricalIndex : An Index with an underlying ``Categorical``.
Notes
-----
See the `user guide
<https://pandas.pydata.org/pandas-docs/stable/user_guide/categorical.html>`_
for more.
Examples
--------
>>> pd.Categorical([1, 2, 3, 1, 2, 3])
[1, 2, 3, 1, 2, 3]
Categories (3, int64): [1, 2, 3]
>>> pd.Categorical(['a', 'b', 'c', 'a', 'b', 'c'])
[a, b, c, a, b, c]
Categories (3, object): [a, b, c]
Ordered `Categoricals` can be sorted according to the custom order
of the categories and can have a min and max value.
>>> c = pd.Categorical(['a', 'b', 'c', 'a', 'b', 'c'], ordered=True,
... categories=['c', 'b', 'a'])
>>> c
[a, b, c, a, b, c]
Categories (3, object): [c < b < a]
>>> c.min()
'c'
"""
# For comparisons, so that numpy uses our implementation if the compare
# ops, which raise
__array_priority__ = 1000
_dtype = CategoricalDtype(ordered=False)
# tolist is not actually deprecated, just suppressed in the __dir__
_deprecations = PandasObject._deprecations | frozenset(["tolist"])
_typ = "categorical"
def __init__(
self, values, categories=None, ordered=None, dtype=None, fastpath=False
):
dtype = CategoricalDtype._from_values_or_dtype(
values, categories, ordered, dtype
)
# At this point, dtype is always a CategoricalDtype, but
# we may have dtype.categories be None, and we need to
# infer categories in a factorization step further below
if fastpath:
self._codes = coerce_indexer_dtype(values, dtype.categories)
self._dtype = self._dtype.update_dtype(dtype)
return
# null_mask indicates missing values we want to exclude from inference.
# This means: only missing values in list-likes (not arrays/ndframes).
null_mask = np.array(False)
# sanitize input
if is_categorical_dtype(values):
if dtype.categories is None:
dtype = CategoricalDtype(values.categories, dtype.ordered)
elif not isinstance(values, (ABCIndexClass, ABCSeries)):
# sanitize_array coerces np.nan to a string under certain versions
# of numpy
values = maybe_infer_to_datetimelike(values, convert_dates=True)
if not isinstance(values, np.ndarray):
values = _convert_to_list_like(values)
# By convention, empty lists result in object dtype:
sanitize_dtype = "object" if len(values) == 0 else None
null_mask = isna(values)
if null_mask.any():
values = [values[idx] for idx in np.where(~null_mask)[0]]
values = sanitize_array(values, None, dtype=sanitize_dtype)
if dtype.categories is None:
try:
codes, categories = factorize(values, sort=True)
except TypeError as err:
codes, categories = factorize(values, sort=False)
if dtype.ordered:
# raise, as we don't have a sortable data structure and so
# the user should give us one by specifying categories
raise TypeError(
"'values' is not ordered, please "
"explicitly specify the categories order "
"by passing in a categories argument."
) from err
except ValueError as err:
# FIXME
raise NotImplementedError(
"> 1 ndim Categorical are not supported at this time"
) from err
# we're inferring from values
dtype = CategoricalDtype(categories, dtype.ordered)
elif is_categorical_dtype(values):
old_codes = (
values._values.codes if isinstance(values, ABCSeries) else values.codes
)
codes = _recode_for_categories(
old_codes, values.dtype.categories, dtype.categories
)
else:
codes = _get_codes_for_values(values, dtype.categories)
if null_mask.any():
# Reinsert -1 placeholders for previously removed missing values
full_codes = -np.ones(null_mask.shape, dtype=codes.dtype)
full_codes[~null_mask] = codes
codes = full_codes
self._dtype = self._dtype.update_dtype(dtype)
self._codes = coerce_indexer_dtype(codes, dtype.categories)
@property
def categories(self):
"""
The categories of this categorical.
Setting assigns new values to each category (effectively a rename of
each individual category).
The assigned value has to be a list-like object. All items must be
unique and the number of items in the new categories must be the same
as the number of items in the old categories.
Assigning to `categories` is a inplace operation!
Raises
------
ValueError
If the new categories do not validate as categories or if the
number of new categories is unequal the number of old categories
See Also
--------
rename_categories
reorder_categories
add_categories
remove_categories
remove_unused_categories
set_categories
"""
return self.dtype.categories
@categories.setter
def categories(self, categories):
new_dtype = CategoricalDtype(categories, ordered=self.ordered)
if self.dtype.categories is not None and len(self.dtype.categories) != len(
new_dtype.categories
):
raise ValueError(
"new categories need to have the same number of "
"items as the old categories!"
)
self._dtype = new_dtype
@property
def ordered(self) -> Ordered:
"""
Whether the categories have an ordered relationship.
"""
return self.dtype.ordered
@property
def dtype(self) -> CategoricalDtype:
"""
The :class:`~pandas.api.types.CategoricalDtype` for this instance.
"""
return self._dtype
@property
def _ndarray_values(self) -> np.ndarray:
return self.codes
@property
def _constructor(self) -> Type["Categorical"]:
return Categorical
@classmethod
def _from_sequence(cls, scalars, dtype=None, copy=False):
return Categorical(scalars, dtype=dtype)
def _formatter(self, boxed=False):
# Defer to CategoricalFormatter's formatter.
return None
def copy(self) -> "Categorical":
"""
Copy constructor.
"""
return self._constructor(
values=self._codes.copy(), dtype=self.dtype, fastpath=True
)
def astype(self, dtype: Dtype, copy: bool = True) -> ArrayLike:
"""
Coerce this type to another dtype
Parameters
----------
dtype : numpy dtype or pandas type
copy : bool, default True
By default, astype always returns a newly allocated object.
If copy is set to False and dtype is categorical, the original
object is returned.
"""
if is_categorical_dtype(dtype):
dtype = cast(Union[str, CategoricalDtype], dtype)
# GH 10696/18593
dtype = self.dtype.update_dtype(dtype)
self = self.copy() if copy else self
if dtype == self.dtype:
return self
return self._set_dtype(dtype)
if is_extension_array_dtype(dtype):
return array(self, dtype=dtype, copy=copy) # type: ignore # GH 28770
if is_integer_dtype(dtype) and self.isna().any():
raise ValueError("Cannot convert float NaN to integer")
return np.array(self, dtype=dtype, copy=copy)
@cache_readonly
def size(self) -> int:
"""
Return the len of myself.
"""
return self._codes.size
@cache_readonly
def itemsize(self) -> int:
"""
return the size of a single category
"""
return self.categories.itemsize
def tolist(self) -> List[Scalar]:
"""
Return a list of the values.
These are each a scalar type, which is a Python scalar
(for str, int, float) or a pandas scalar
(for Timestamp/Timedelta/Interval/Period)
"""
return list(self)
to_list = tolist
@classmethod
def _from_inferred_categories(
cls, inferred_categories, inferred_codes, dtype, true_values=None
):
"""
Construct a Categorical from inferred values.
For inferred categories (`dtype` is None) the categories are sorted.
For explicit `dtype`, the `inferred_categories` are cast to the
appropriate type.
Parameters
----------
inferred_categories : Index
inferred_codes : Index
dtype : CategoricalDtype or 'category'
true_values : list, optional
If none are provided, the default ones are
"True", "TRUE", and "true."
Returns
-------
Categorical
"""
from pandas import Index, to_numeric, to_datetime, to_timedelta
cats = Index(inferred_categories)
known_categories = (
isinstance(dtype, CategoricalDtype) and dtype.categories is not None
)
if known_categories:
# Convert to a specialized type with `dtype` if specified.
if dtype.categories.is_numeric():
cats = to_numeric(inferred_categories, errors="coerce")
elif is_datetime64_dtype(dtype.categories):
cats = to_datetime(inferred_categories, errors="coerce")
elif is_timedelta64_dtype(dtype.categories):
cats = to_timedelta(inferred_categories, errors="coerce")
elif dtype.categories.is_boolean():
if true_values is None:
true_values = ["True", "TRUE", "true"]
cats = cats.isin(true_values)
if known_categories:
# Recode from observation order to dtype.categories order.
categories = dtype.categories
codes = _recode_for_categories(inferred_codes, cats, categories)
elif not cats.is_monotonic_increasing:
# Sort categories and recode for unknown categories.
unsorted = cats.copy()
categories = cats.sort_values()
codes = _recode_for_categories(inferred_codes, unsorted, categories)
dtype = CategoricalDtype(categories, ordered=False)
else:
dtype = CategoricalDtype(cats, ordered=False)
codes = inferred_codes
return cls(codes, dtype=dtype, fastpath=True)
@classmethod
def from_codes(cls, codes, categories=None, ordered=None, dtype=None):
"""
Make a Categorical type from codes and categories or dtype.
This constructor is useful if you already have codes and
categories/dtype and so do not need the (computation intensive)
factorization step, which is usually done on the constructor.
If your data does not follow this convention, please use the normal
constructor.
Parameters
----------
codes : array-like of int
An integer array, where each integer points to a category in
categories or dtype.categories, or else is -1 for NaN.
categories : index-like, optional
The categories for the categorical. Items need to be unique.
If the categories are not given here, then they must be provided
in `dtype`.
ordered : bool, optional
Whether or not this categorical is treated as an ordered
categorical. If not given here or in `dtype`, the resulting
categorical will be unordered.
dtype : CategoricalDtype or "category", optional
If :class:`CategoricalDtype`, cannot be used together with
`categories` or `ordered`.
.. versionadded:: 0.24.0
When `dtype` is provided, neither `categories` nor `ordered`
should be provided.
Returns
-------
Categorical
Examples
--------
>>> dtype = pd.CategoricalDtype(['a', 'b'], ordered=True)
>>> pd.Categorical.from_codes(codes=[0, 1, 0, 1], dtype=dtype)
[a, b, a, b]
Categories (2, object): [a < b]
"""
dtype = CategoricalDtype._from_values_or_dtype(
categories=categories, ordered=ordered, dtype=dtype
)
if dtype.categories is None:
msg = (
"The categories must be provided in 'categories' or "
"'dtype'. Both were None."
)
raise ValueError(msg)
if is_extension_array_dtype(codes) and is_integer_dtype(codes):
# Avoid the implicit conversion of Int to object
if isna(codes).any():
raise ValueError("codes cannot contain NA values")
codes = codes.to_numpy(dtype=np.int64)
else:
codes = np.asarray(codes)
if len(codes) and not is_integer_dtype(codes):
raise ValueError("codes need to be array-like integers")
if len(codes) and (codes.max() >= len(dtype.categories) or codes.min() < -1):
raise ValueError("codes need to be between -1 and len(categories)-1")
return cls(codes, dtype=dtype, fastpath=True)
def _get_codes(self):
"""
Get the codes.
Returns
-------
codes : integer array view
A non writable view of the `codes` array.
"""
v = self._codes.view()
v.flags.writeable = False
return v
def _set_codes(self, codes):
"""
Not settable by the user directly
"""
raise ValueError("cannot set Categorical codes directly")
codes = property(fget=_get_codes, fset=_set_codes, doc=_codes_doc)
def _set_categories(self, categories, fastpath=False):
"""
Sets new categories inplace
Parameters
----------
fastpath : bool, default False
Don't perform validation of the categories for uniqueness or nulls
Examples
--------
>>> c = pd.Categorical(['a', 'b'])
>>> c
[a, b]
Categories (2, object): [a, b]
>>> c._set_categories(pd.Index(['a', 'c']))
>>> c
[a, c]
Categories (2, object): [a, c]
"""
if fastpath:
new_dtype = CategoricalDtype._from_fastpath(categories, self.ordered)
else:
new_dtype = CategoricalDtype(categories, ordered=self.ordered)
if (
not fastpath
and self.dtype.categories is not None
and len(new_dtype.categories) != len(self.dtype.categories)
):
raise ValueError(
"new categories need to have the same number of "
"items than the old categories!"
)
self._dtype = new_dtype
def _set_dtype(self, dtype: CategoricalDtype) -> "Categorical":
"""
Internal method for directly updating the CategoricalDtype
Parameters
----------
dtype : CategoricalDtype
Notes
-----
We don't do any validation here. It's assumed that the dtype is
a (valid) instance of `CategoricalDtype`.
"""
codes = _recode_for_categories(self.codes, self.categories, dtype.categories)
return type(self)(codes, dtype=dtype, fastpath=True)
def set_ordered(self, value, inplace=False):
"""
Set the ordered attribute to the boolean value.
Parameters
----------
value : bool
Set whether this categorical is ordered (True) or not (False).
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to the value.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
new_dtype = CategoricalDtype(self.categories, ordered=value)
cat = self if inplace else self.copy()
cat._dtype = new_dtype
if not inplace:
return cat
def as_ordered(self, inplace=False):
"""
Set the Categorical to be ordered.
Parameters
----------
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to True.
Returns
-------
Categorical
Ordered Categorical.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
return self.set_ordered(True, inplace=inplace)
def as_unordered(self, inplace=False):
"""
Set the Categorical to be unordered.
Parameters
----------
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to False.
Returns
-------
Categorical
Unordered Categorical.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
return self.set_ordered(False, inplace=inplace)
def set_categories(self, new_categories, ordered=None, rename=False, inplace=False):
"""
Set the categories to the specified new_categories.
`new_categories` can include new categories (which will result in
unused categories) or remove old categories (which results in values
set to NaN). If `rename==True`, the categories will simple be renamed
(less or more items than in old categories will result in values set to
NaN or in unused categories respectively).
This method can be used to perform more than one action of adding,
removing, and reordering simultaneously and is therefore faster than
performing the individual steps via the more specialised methods.
On the other hand this methods does not do checks (e.g., whether the
old categories are included in the new categories on a reorder), which
can result in surprising changes, for example when using special string
dtypes, which does not considers a S1 string equal to a single char
python string.
Parameters
----------
new_categories : Index-like
The categories in new order.
ordered : bool, default False
Whether or not the categorical is treated as a ordered categorical.
If not given, do not change the ordered information.
rename : bool, default False
Whether or not the new_categories should be considered as a rename
of the old categories or as reordered categories.
inplace : bool, default False
Whether or not to reorder the categories in-place or return a copy
of this categorical with reordered categories.
Returns
-------
Categorical with reordered categories or None if inplace.
Raises
------
ValueError
If new_categories does not validate as categories
See Also
--------
rename_categories
reorder_categories
add_categories
remove_categories
remove_unused_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if ordered is None:
ordered = self.dtype.ordered
new_dtype = CategoricalDtype(new_categories, ordered=ordered)
cat = self if inplace else self.copy()
if rename:
if cat.dtype.categories is not None and len(new_dtype.categories) < len(
cat.dtype.categories
):
# remove all _codes which are larger and set to -1/NaN
cat._codes[cat._codes >= len(new_dtype.categories)] = -1
else:
codes = _recode_for_categories(
cat.codes, cat.categories, new_dtype.categories
)
cat._codes = codes
cat._dtype = new_dtype
if not inplace:
return cat
def rename_categories(self, new_categories, inplace=False):
"""
Rename categories.
Parameters
----------
new_categories : list-like, dict-like or callable
New categories which will replace old categories.
* list-like: all items must be unique and the number of items in
the new categories must match the existing number of categories.
* dict-like: specifies a mapping from
old categories to new. Categories not contained in the mapping
are passed through and extra categories in the mapping are
ignored.
.. versionadded:: 0.21.0.
* callable : a callable that is called on all items in the old
categories and whose return values comprise the new categories.
.. versionadded:: 0.23.0.
inplace : bool, default False
Whether or not to rename the categories inplace or return a copy of
this categorical with renamed categories.
Returns
-------
cat : Categorical or None
With ``inplace=False``, the new categorical is returned.
With ``inplace=True``, there is no return value.
Raises
------
ValueError
If new categories are list-like and do not have the same number of
items than the current categories or do not validate as categories
See Also
--------
reorder_categories
add_categories
remove_categories
remove_unused_categories
set_categories
Examples
--------
>>> c = pd.Categorical(['a', 'a', 'b'])
>>> c.rename_categories([0, 1])
[0, 0, 1]
Categories (2, int64): [0, 1]
For dict-like ``new_categories``, extra keys are ignored and
categories not in the dictionary are passed through
>>> c.rename_categories({'a': 'A', 'c': 'C'})
[A, A, b]
Categories (2, object): [A, b]
You may also provide a callable to create the new categories
>>> c.rename_categories(lambda x: x.upper())
[A, A, B]
Categories (2, object): [A, B]
"""
inplace = validate_bool_kwarg(inplace, "inplace")
cat = self if inplace else self.copy()
if is_dict_like(new_categories):
cat.categories = [new_categories.get(item, item) for item in cat.categories]
elif callable(new_categories):
cat.categories = [new_categories(item) for item in cat.categories]
else:
cat.categories = new_categories
if not inplace:
return cat
def reorder_categories(self, new_categories, ordered=None, inplace=False):
"""
Reorder categories as specified in new_categories.
`new_categories` need to include all old categories and no new category
items.
Parameters
----------
new_categories : Index-like
The categories in new order.
ordered : bool, optional
Whether or not the categorical is treated as a ordered categorical.
If not given, do not change the ordered information.
inplace : bool, default False
Whether or not to reorder the categories inplace or return a copy of
this categorical with reordered categories.
Returns
-------
cat : Categorical with reordered categories or None if inplace.
Raises
------
ValueError
If the new categories do not contain all old category items or any
new ones
See Also
--------
rename_categories
add_categories
remove_categories
remove_unused_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if set(self.dtype.categories) != set(new_categories):
raise ValueError(
"items in new_categories are not the same as in old categories"
)
return self.set_categories(new_categories, ordered=ordered, inplace=inplace)
def add_categories(self, new_categories, inplace=False):
"""
Add new categories.
`new_categories` will be included at the last/highest place in the
categories and will be unused directly after this call.
Parameters
----------
new_categories : category or list-like of category
The new categories to be included.
inplace : bool, default False
Whether or not to add the categories inplace or return a copy of
this categorical with added categories.
Returns
-------
cat : Categorical with new categories added or None if inplace.
Raises
------
ValueError
If the new categories include old categories or do not validate as
categories
See Also
--------
rename_categories
reorder_categories
remove_categories
remove_unused_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not is_list_like(new_categories):
new_categories = [new_categories]
already_included = set(new_categories) & set(self.dtype.categories)
if len(already_included) != 0:
raise ValueError(
f"new categories must not include old categories: {already_included}"
)
new_categories = list(self.dtype.categories) + list(new_categories)
new_dtype = CategoricalDtype(new_categories, self.ordered)
cat = self if inplace else self.copy()
cat._dtype = new_dtype
cat._codes = coerce_indexer_dtype(cat._codes, new_dtype.categories)
if not inplace:
return cat
def remove_categories(self, removals, inplace=False):
"""
Remove the specified categories.
`removals` must be included in the old categories. Values which were in
the removed categories will be set to NaN
Parameters
----------
removals : category or list of categories
The categories which should be removed.
inplace : bool, default False
Whether or not to remove the categories inplace or return a copy of
this categorical with removed categories.
Returns
-------
cat : Categorical with removed categories or None if inplace.
Raises
------
ValueError
If the removals are not contained in the categories
See Also
--------
rename_categories
reorder_categories
add_categories
remove_unused_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not is_list_like(removals):
removals = [removals]
removal_set = set(removals)
not_included = removal_set - set(self.dtype.categories)
new_categories = [c for c in self.dtype.categories if c not in removal_set]
# GH 10156
if any(isna(removals)):
not_included = {x for x in not_included if notna(x)}
new_categories = [x for x in new_categories if notna(x)]
if len(not_included) != 0:
raise ValueError(f"removals must all be in old categories: {not_included}")
return self.set_categories(
new_categories, ordered=self.ordered, rename=False, inplace=inplace
)
def remove_unused_categories(self, inplace=False):
"""
Remove categories which are not used.
Parameters
----------
inplace : bool, default False
Whether or not to drop unused categories inplace or return a copy of
this categorical with unused categories dropped.
Returns
-------
cat : Categorical with unused categories dropped or None if inplace.
See Also
--------
rename_categories
reorder_categories
add_categories
remove_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
cat = self if inplace else self.copy()
idx, inv = np.unique(cat._codes, return_inverse=True)
if idx.size != 0 and idx[0] == -1: # na sentinel
idx, inv = idx[1:], inv - 1
new_categories = cat.dtype.categories.take(idx)
new_dtype = CategoricalDtype._from_fastpath(
new_categories, ordered=self.ordered
)
cat._dtype = new_dtype
cat._codes = coerce_indexer_dtype(inv, new_dtype.categories)
if not inplace:
return cat
def map(self, mapper):
"""
Map categories using input correspondence (dict, Series, or function).
Maps the categories to new categories. If the mapping correspondence is
one-to-one the result is a :class:`~pandas.Categorical` which has the
same order property as the original, otherwise a :class:`~pandas.Index`
is returned. NaN values are unaffected.
If a `dict` or :class:`~pandas.Series` is used any unmapped category is
mapped to `NaN`. Note that if this happens an :class:`~pandas.Index`
will be returned.
Parameters
----------
mapper : function, dict, or Series
Mapping correspondence.
Returns
-------
pandas.Categorical or pandas.Index
Mapped categorical.
See Also
--------
CategoricalIndex.map : Apply a mapping correspondence on a
:class:`~pandas.CategoricalIndex`.
Index.map : Apply a mapping correspondence on an
:class:`~pandas.Index`.
Series.map : Apply a mapping correspondence on a
:class:`~pandas.Series`.
Series.apply : Apply more complex functions on a
:class:`~pandas.Series`.
Examples
--------
>>> cat = pd.Categorical(['a', 'b', 'c'])
>>> cat
[a, b, c]
Categories (3, object): [a, b, c]
>>> cat.map(lambda x: x.upper())
[A, B, C]
Categories (3, object): [A, B, C]
>>> cat.map({'a': 'first', 'b': 'second', 'c': 'third'})
[first, second, third]
Categories (3, object): [first, second, third]
If the mapping is one-to-one the ordering of the categories is
preserved:
>>> cat = pd.Categorical(['a', 'b', 'c'], ordered=True)
>>> cat
[a, b, c]
Categories (3, object): [a < b < c]
>>> cat.map({'a': 3, 'b': 2, 'c': 1})
[3, 2, 1]
Categories (3, int64): [3 < 2 < 1]
If the mapping is not one-to-one an :class:`~pandas.Index` is returned:
>>> cat.map({'a': 'first', 'b': 'second', 'c': 'first'})
Index(['first', 'second', 'first'], dtype='object')
If a `dict` is used, all unmapped categories are mapped to `NaN` and
the result is an :class:`~pandas.Index`:
>>> cat.map({'a': 'first', 'b': 'second'})
Index(['first', 'second', nan], dtype='object')
"""
new_categories = self.categories.map(mapper)
try:
return self.from_codes(
self._codes.copy(), categories=new_categories, ordered=self.ordered
)
except ValueError:
# NA values are represented in self._codes with -1
# np.take causes NA values to take final element in new_categories
if np.any(self._codes == -1):
new_categories = new_categories.insert(len(new_categories), np.nan)
return np.take(new_categories, self._codes)
__eq__ = _cat_compare_op(operator.eq)
__ne__ = _cat_compare_op(operator.ne)
__lt__ = _cat_compare_op(operator.lt)
__gt__ = _cat_compare_op(operator.gt)
__le__ = _cat_compare_op(operator.le)
__ge__ = _cat_compare_op(operator.ge)
# for Series/ndarray like compat
@property
def shape(self):
"""
Shape of the Categorical.
For internal compatibility with numpy arrays.
Returns
-------
shape : tuple
"""
return tuple([len(self._codes)])
def shift(self, periods, fill_value=None):
"""
Shift Categorical by desired number of periods.
Parameters
----------
periods : int
Number of periods to move, can be positive or negative
fill_value : object, optional
The scalar value to use for newly introduced missing values.
.. versionadded:: 0.24.0
Returns
-------
shifted : Categorical
"""
# since categoricals always have ndim == 1, an axis parameter
# doesn't make any sense here.
codes = self.codes
if codes.ndim > 1:
raise NotImplementedError("Categorical with ndim > 1.")
if np.prod(codes.shape) and (periods != 0):
codes = np.roll(codes, ensure_platform_int(periods), axis=0)
if isna(fill_value):
fill_value = -1
elif fill_value in self.categories:
fill_value = self.categories.get_loc(fill_value)
else:
raise ValueError(
f"'fill_value={fill_value}' is not present "
"in this Categorical's categories"
)
if periods > 0:
codes[:periods] = fill_value
else:
codes[periods:] = fill_value
return self.from_codes(codes, dtype=self.dtype)
def __array__(self, dtype=None) -> np.ndarray:
"""
The numpy array interface.
Returns
-------
numpy.array
A numpy array of either the specified dtype or,
if dtype==None (default), the same dtype as
categorical.categories.dtype.
"""
ret = take_1d(self.categories.values, self._codes)
if dtype and not is_dtype_equal(dtype, self.categories.dtype):
return np.asarray(ret, dtype)
if is_extension_array_dtype(ret):
# When we're a Categorical[ExtensionArray], like Interval,
# we need to ensure __array__ get's all the way to an
# ndarray.
ret = np.asarray(ret)
return ret
def __array_ufunc__(self, ufunc, method, *inputs, **kwargs):
# for binary ops, use our custom dunder methods
result = ops.maybe_dispatch_ufunc_to_dunder_op(
self, ufunc, method, *inputs, **kwargs
)
if result is not NotImplemented:
return result
# for all other cases, raise for now (similarly as what happens in
# Series.__array_prepare__)
raise TypeError(
f"Object with dtype {self.dtype} cannot perform "
f"the numpy op {ufunc.__name__}"
)
def __setstate__(self, state):
"""Necessary for making this object picklable"""
if not isinstance(state, dict):
raise Exception("invalid pickle state")
# compat with pre 0.21.0 CategoricalDtype change
if "_dtype" not in state:
state["_dtype"] = CategoricalDtype(state["_categories"], state["_ordered"])
for k, v in state.items():
setattr(self, k, v)
@property
def T(self):
"""
Return transposed numpy array.
"""
return self
@property
def nbytes(self):
return self._codes.nbytes + self.dtype.categories.values.nbytes
def memory_usage(self, deep=False):
"""
Memory usage of my values
Parameters
----------
deep : bool
Introspect the data deeply, interrogate
`object` dtypes for system-level memory consumption
Returns
-------
bytes used
Notes
-----
Memory usage does not include memory consumed by elements that
are not components of the array if deep=False
See Also
--------
numpy.ndarray.nbytes
"""
return self._codes.nbytes + self.dtype.categories.memory_usage(deep=deep)
@Substitution(klass="Categorical")
@Appender(_shared_docs["searchsorted"])
def searchsorted(self, value, side="left", sorter=None):
# searchsorted is very performance sensitive. By converting codes
# to same dtype as self.codes, we get much faster performance.
if is_scalar(value):
codes = self.categories.get_loc(value)
codes = self.codes.dtype.type(codes)
else:
locs = [self.categories.get_loc(x) for x in value]
codes = np.array(locs, dtype=self.codes.dtype)
return self.codes.searchsorted(codes, side=side, sorter=sorter)
def isna(self):
"""
Detect missing values
Missing values (-1 in .codes) are detected.
Returns
-------
a boolean array of whether my values are null
See Also
--------
isna : Top-level isna.
isnull : Alias of isna.
Categorical.notna : Boolean inverse of Categorical.isna.
"""
ret = self._codes == -1
return ret
isnull = isna
def notna(self):
"""
Inverse of isna
Both missing values (-1 in .codes) and NA as a category are detected as
null.
Returns
-------
a boolean array of whether my values are not null
See Also
--------
notna : Top-level notna.
notnull : Alias of notna.
Categorical.isna : Boolean inverse of Categorical.notna.
"""
return ~self.isna()
notnull = notna
def put(self, *args, **kwargs):
"""
Replace specific elements in the Categorical with given values.
"""
raise NotImplementedError(("'put' is not yet implemented for Categorical"))
def dropna(self):
"""
Return the Categorical without null values.
Missing values (-1 in .codes) are detected.
Returns
-------
valid : Categorical
"""
result = self[self.notna()]
return result
def value_counts(self, dropna=True):
"""
Return a Series containing counts of each category.
Every category will have an entry, even those with a count of 0.
Parameters
----------
dropna : bool, default True
Don't include counts of NaN.
Returns
-------
counts : Series
See Also
--------
Series.value_counts
"""
from pandas import Series, CategoricalIndex
code, cat = self._codes, self.categories
ncat, mask = len(cat), 0 <= code
ix, clean = np.arange(ncat), mask.all()
if dropna or clean:
obs = code if clean else code[mask]
count = np.bincount(obs, minlength=ncat or 0)
else:
count = np.bincount(np.where(mask, code, ncat))
ix = np.append(ix, -1)
ix = self._constructor(ix, dtype=self.dtype, fastpath=True)
return Series(count, index=CategoricalIndex(ix), dtype="int64")
def _internal_get_values(self):
"""
Return the values.
For internal compatibility with pandas formatting.
Returns
-------
np.ndarray or Index
A numpy array of the same dtype as categorical.categories.dtype or
Index if datetime / periods.
"""
# if we are a datetime and period index, return Index to keep metadata
if needs_i8_conversion(self.categories):
return self.categories.take(self._codes, fill_value=np.nan)
elif is_integer_dtype(self.categories) and -1 in self._codes:
return self.categories.astype("object").take(self._codes, fill_value=np.nan)
return np.array(self)
def check_for_ordered(self, op):
""" assert that we are ordered """
if not self.ordered:
raise TypeError(
f"Categorical is not ordered for operation {op}\n"
"you can use .as_ordered() to change the "
"Categorical to an ordered one\n"
)
def _values_for_argsort(self):
return self._codes.copy()
def argsort(self, ascending=True, kind="quicksort", **kwargs):
"""
Return the indices that would sort the Categorical.
.. versionchanged:: 0.25.0
Changed to sort missing values at the end.
Parameters
----------
ascending : bool, default True
Whether the indices should result in an ascending
or descending sort.
kind : {'quicksort', 'mergesort', 'heapsort'}, optional
Sorting algorithm.
**kwargs:
passed through to :func:`numpy.argsort`.
Returns
-------
numpy.array
See Also
--------
numpy.ndarray.argsort
Notes
-----
While an ordering is applied to the category values, arg-sorting
in this context refers more to organizing and grouping together
based on matching category values. Thus, this function can be
called on an unordered Categorical instance unlike the functions
'Categorical.min' and 'Categorical.max'.
Examples
--------
>>> pd.Categorical(['b', 'b', 'a', 'c']).argsort()
array([2, 0, 1, 3])
>>> cat = pd.Categorical(['b', 'b', 'a', 'c'],
... categories=['c', 'b', 'a'],
... ordered=True)
>>> cat.argsort()
array([3, 0, 1, 2])
Missing values are placed at the end
>>> cat = pd.Categorical([2, None, 1])
>>> cat.argsort()
array([2, 0, 1])
"""
return super().argsort(ascending=ascending, kind=kind, **kwargs)
def sort_values(self, inplace=False, ascending=True, na_position="last"):
"""
Sort the Categorical by category value returning a new
Categorical by default.
While an ordering is applied to the category values, sorting in this
context refers more to organizing and grouping together based on
matching category values. Thus, this function can be called on an
unordered Categorical instance unlike the functions 'Categorical.min'
and 'Categorical.max'.
Parameters
----------
inplace : bool, default False
Do operation in place.
ascending : bool, default True
Order ascending. Passing False orders descending. The
ordering parameter provides the method by which the
category values are organized.
na_position : {'first', 'last'} (optional, default='last')
'first' puts NaNs at the beginning
'last' puts NaNs at the end
Returns
-------
Categorical or None
See Also
--------
Categorical.sort
Series.sort_values
Examples
--------
>>> c = pd.Categorical([1, 2, 2, 1, 5])
>>> c
[1, 2, 2, 1, 5]
Categories (3, int64): [1, 2, 5]
>>> c.sort_values()
[1, 1, 2, 2, 5]
Categories (3, int64): [1, 2, 5]
>>> c.sort_values(ascending=False)
[5, 2, 2, 1, 1]
Categories (3, int64): [1, 2, 5]
Inplace sorting can be done as well:
>>> c.sort_values(inplace=True)
>>> c
[1, 1, 2, 2, 5]
Categories (3, int64): [1, 2, 5]
>>>
>>> c = pd.Categorical([1, 2, 2, 1, 5])
'sort_values' behaviour with NaNs. Note that 'na_position'
is independent of the 'ascending' parameter:
>>> c = pd.Categorical([np.nan, 2, 2, np.nan, 5])
>>> c
[NaN, 2.0, 2.0, NaN, 5.0]
Categories (2, int64): [2, 5]
>>> c.sort_values()
[2.0, 2.0, 5.0, NaN, NaN]
Categories (2, int64): [2, 5]
>>> c.sort_values(ascending=False)
[5.0, 2.0, 2.0, NaN, NaN]
Categories (2, int64): [2, 5]
>>> c.sort_values(na_position='first')
[NaN, NaN, 2.0, 2.0, 5.0]
Categories (2, int64): [2, 5]
>>> c.sort_values(ascending=False, na_position='first')
[NaN, NaN, 5.0, 2.0, 2.0]
Categories (2, int64): [2, 5]
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if na_position not in ["last", "first"]:
raise ValueError(f"invalid na_position: {repr(na_position)}")
sorted_idx = nargsort(self, ascending=ascending, na_position=na_position)
if inplace:
self._codes = self._codes[sorted_idx]
else:
return self._constructor(
values=self._codes[sorted_idx], dtype=self.dtype, fastpath=True
)
def _values_for_rank(self):
"""
For correctly ranking ordered categorical data. See GH#15420
Ordered categorical data should be ranked on the basis of
codes with -1 translated to NaN.
Returns
-------
numpy.array
"""
from pandas import Series
if self.ordered:
values = self.codes
mask = values == -1
if mask.any():
values = values.astype("float64")
values[mask] = np.nan
elif self.categories.is_numeric():
values = np.array(self)
else:
# reorder the categories (so rank can use the float codes)
# instead of passing an object array to rank
values = np.array(
self.rename_categories(Series(self.categories).rank().values)
)
return values
def view(self, dtype=None):
if dtype is not None:
raise NotImplementedError(dtype)
return self._constructor(values=self._codes, dtype=self.dtype, fastpath=True)
def to_dense(self):
"""
Return my 'dense' representation
For internal compatibility with numpy arrays.
Returns
-------
dense : array
"""
return np.asarray(self)
def fillna(self, value=None, method=None, limit=None):
"""
Fill NA/NaN values using the specified method.
Parameters
----------
value : scalar, dict, Series
If a scalar value is passed it is used to fill all missing values.
Alternatively, a Series or dict can be used to fill in different
values for each index. The value should not be a list. The
value(s) passed should either be in the categories or should be
NaN.
method : {'backfill', 'bfill', 'pad', 'ffill', None}, default None
Method to use for filling holes in reindexed Series
pad / ffill: propagate last valid observation forward to next valid
backfill / bfill: use NEXT valid observation to fill gap
limit : int, default None
(Not implemented yet for Categorical!)
If method is specified, this is the maximum number of consecutive
NaN values to forward/backward fill. In other words, if there is
a gap with more than this number of consecutive NaNs, it will only
be partially filled. If method is not specified, this is the
maximum number of entries along the entire axis where NaNs will be
filled.
Returns
-------
filled : Categorical with NA/NaN filled
"""
value, method = validate_fillna_kwargs(
value, method, validate_scalar_dict_value=False
)
if value is None:
value = np.nan
if limit is not None:
raise NotImplementedError(
"specifying a limit for fillna has not been implemented yet"
)
codes = self._codes
# pad / bfill
if method is not None:
values = self.to_dense().reshape(-1, len(self))
values = interpolate_2d(values, method, 0, None, value).astype(
self.categories.dtype
)[0]
codes = _get_codes_for_values(values, self.categories)
else:
# If value is a dict or a Series (a dict value has already
# been converted to a Series)
if isinstance(value, ABCSeries):
if not value[~value.isin(self.categories)].isna().all():
raise ValueError("fill value must be in categories")
values_codes = _get_codes_for_values(value, self.categories)
indexer = np.where(codes == -1)
codes[indexer] = values_codes[indexer]
# If value is not a dict or Series it should be a scalar
elif is_hashable(value):
if not isna(value) and value not in self.categories:
raise ValueError("fill value must be in categories")
mask = codes == -1
if mask.any():
codes = codes.copy()
if isna(value):
codes[mask] = -1
else:
codes[mask] = self.categories.get_loc(value)
else:
raise TypeError(
f"'value' parameter must be a scalar, dict "
f"or Series, but you passed a {type(value).__name__}"
)
return self._constructor(codes, dtype=self.dtype, fastpath=True)
def take(self, indexer, allow_fill: bool = False, fill_value=None):
"""
Take elements from the Categorical.
Parameters
----------
indexer : sequence of int
The indices in `self` to take. The meaning of negative values in
`indexer` depends on the value of `allow_fill`.
allow_fill : bool, default False
How to handle negative values in `indexer`.
* False: negative values in `indices` indicate positional indices
from the right. This is similar to
:func:`numpy.take`.
* True: negative values in `indices` indicate missing values
(the default). These values are set to `fill_value`. Any other
other negative values raise a ``ValueError``.
.. versionchanged:: 1.0.0
Default value changed from ``True`` to ``False``.
fill_value : object
The value to use for `indices` that are missing (-1), when
``allow_fill=True``. This should be the category, i.e. a value
in ``self.categories``, not a code.
Returns
-------
Categorical
This Categorical will have the same categories and ordered as
`self`.
See Also
--------
Series.take : Similar method for Series.
numpy.ndarray.take : Similar method for NumPy arrays.
Examples
--------
>>> cat = pd.Categorical(['a', 'a', 'b'])
>>> cat
[a, a, b]
Categories (2, object): [a, b]
Specify ``allow_fill==False`` to have negative indices mean indexing
from the right.
>>> cat.take([0, -1, -2], allow_fill=False)
[a, b, a]
Categories (2, object): [a, b]
With ``allow_fill=True``, indices equal to ``-1`` mean "missing"
values that should be filled with the `fill_value`, which is
``np.nan`` by default.
>>> cat.take([0, -1, -1], allow_fill=True)
[a, NaN, NaN]
Categories (2, object): [a, b]
The fill value can be specified.
>>> cat.take([0, -1, -1], allow_fill=True, fill_value='a')
[a, a, a]
Categories (3, object): [a, b]
Specifying a fill value that's not in ``self.categories``
will raise a ``TypeError``.
"""
indexer = np.asarray(indexer, dtype=np.intp)
dtype = self.dtype
if isna(fill_value):
fill_value = -1
elif allow_fill:
# convert user-provided `fill_value` to codes
if fill_value in self.categories:
fill_value = self.categories.get_loc(fill_value)
else:
msg = (
f"'fill_value' ('{fill_value}') is not in this "
"Categorical's categories."
)
raise TypeError(msg)
codes = take(self._codes, indexer, allow_fill=allow_fill, fill_value=fill_value)
result = type(self).from_codes(codes, dtype=dtype)
return result
def take_nd(self, indexer, allow_fill: bool = False, fill_value=None):
# GH#27745 deprecate alias that other EAs dont have
warn(
"Categorical.take_nd is deprecated, use Categorical.take instead",
FutureWarning,
stacklevel=2,
)
return self.take(indexer, allow_fill=allow_fill, fill_value=fill_value)
def __len__(self) -> int:
"""
The length of this Categorical.
"""
return len(self._codes)
def __iter__(self):
"""
Returns an Iterator over the values of this Categorical.
"""
return iter(self._internal_get_values().tolist())
def __contains__(self, key) -> bool:
"""
Returns True if `key` is in this Categorical.
"""
# if key is a NaN, check if any NaN is in self.
if is_scalar(key) and isna(key):
return self.isna().any()
return contains(self, key, container=self._codes)
def _tidy_repr(self, max_vals=10, footer=True) -> str:
"""
a short repr displaying only max_vals and an optional (but default
footer)
"""
num = max_vals // 2
head = self[:num]._get_repr(length=False, footer=False)
tail = self[-(max_vals - num) :]._get_repr(length=False, footer=False)
result = f"{head[:-1]}, ..., {tail[1:]}"
if footer:
result = f"{result}\n{self._repr_footer()}"
return str(result)
def _repr_categories(self):
"""
return the base repr for the categories
"""
max_categories = (
10
if get_option("display.max_categories") == 0
else get_option("display.max_categories")
)
from pandas.io.formats import format as fmt
if len(self.categories) > max_categories:
num = max_categories // 2
head = fmt.format_array(self.categories[:num], None)
tail = fmt.format_array(self.categories[-num:], None)
category_strs = head + ["..."] + tail
else:
category_strs = fmt.format_array(self.categories, None)
# Strip all leading spaces, which format_array adds for columns...
category_strs = [x.strip() for x in category_strs]
return category_strs
def _repr_categories_info(self) -> str:
"""
Returns a string representation of the footer.
"""
category_strs = self._repr_categories()
dtype = str(self.categories.dtype)
levheader = f"Categories ({len(self.categories)}, {dtype}): "
width, height = get_terminal_size()
max_width = get_option("display.width") or width
if console.in_ipython_frontend():
# 0 = no breaks
max_width = 0
levstring = ""
start = True
cur_col_len = len(levheader) # header
sep_len, sep = (3, " < ") if self.ordered else (2, ", ")
linesep = sep.rstrip() + "\n" # remove whitespace
for val in category_strs:
if max_width != 0 and cur_col_len + sep_len + len(val) > max_width:
levstring += linesep + (" " * (len(levheader) + 1))
cur_col_len = len(levheader) + 1 # header + a whitespace
elif not start:
levstring += sep
cur_col_len += len(val)
levstring += val
start = False
# replace to simple save space by
return levheader + "[" + levstring.replace(" < ... < ", " ... ") + "]"
def _repr_footer(self) -> str:
info = self._repr_categories_info()
return f"Length: {len(self)}\n{info}"
def _get_repr(self, length=True, na_rep="NaN", footer=True) -> str:
from pandas.io.formats import format as fmt
formatter = fmt.CategoricalFormatter(
self, length=length, na_rep=na_rep, footer=footer
)
result = formatter.to_string()
return str(result)
def __repr__(self) -> str:
"""
String representation.
"""
_maxlen = 10
if len(self._codes) > _maxlen:
result = self._tidy_repr(_maxlen)
elif len(self._codes) > 0:
result = self._get_repr(length=len(self) > _maxlen)
else:
msg = self._get_repr(length=False, footer=True).replace("\n", ", ")
result = f"[], {msg}"
return result
def _maybe_coerce_indexer(self, indexer):
"""
return an indexer coerced to the codes dtype
"""
if isinstance(indexer, np.ndarray) and indexer.dtype.kind == "i":
indexer = indexer.astype(self._codes.dtype)
return indexer
def __getitem__(self, key):
"""
Return an item.
"""
if isinstance(key, (int, np.integer)):
i = self._codes[key]
if i == -1:
return np.nan
else:
return self.categories[i]
key = check_array_indexer(self, key)
result = self._codes[key]
if result.ndim > 1:
deprecate_ndim_indexing(result)
return result
return self._constructor(result, dtype=self.dtype, fastpath=True)
def __setitem__(self, key, value):
"""
Item assignment.
Raises
------
ValueError
If (one or more) Value is not in categories or if a assigned
`Categorical` does not have the same categories
"""
value = extract_array(value, extract_numpy=True)
# require identical categories set
if isinstance(value, Categorical):
if not is_dtype_equal(self, value):
raise ValueError(
"Cannot set a Categorical with another, "
"without identical categories"
)
if not self.categories.equals(value.categories):
new_codes = _recode_for_categories(
value.codes, value.categories, self.categories
)
value = Categorical.from_codes(new_codes, dtype=self.dtype)
rvalue = value if is_list_like(value) else [value]
from pandas import Index
to_add = Index(rvalue).difference(self.categories)
# no assignments of values not in categories, but it's always ok to set
# something to np.nan
if len(to_add) and not isna(to_add).all():
raise ValueError(
"Cannot setitem on a Categorical with a new "
"category, set the categories first"
)
# set by position
if isinstance(key, (int, np.integer)):
pass
# tuple of indexers (dataframe)
elif isinstance(key, tuple):
# only allow 1 dimensional slicing, but can
# in a 2-d case be passd (slice(None),....)
if len(key) == 2:
if not com.is_null_slice(key[0]):
raise AssertionError("invalid slicing for a 1-ndim categorical")
key = key[1]
elif len(key) == 1:
key = key[0]
else:
raise AssertionError("invalid slicing for a 1-ndim categorical")
# slicing in Series or Categorical
elif isinstance(key, slice):
pass
# else: array of True/False in Series or Categorical
lindexer = self.categories.get_indexer(rvalue)
lindexer = self._maybe_coerce_indexer(lindexer)
key = check_array_indexer(self, key)
self._codes[key] = lindexer
def _reverse_indexer(self) -> Dict[Hashable, np.ndarray]:
"""
Compute the inverse of a categorical, returning
a dict of categories -> indexers.
*This is an internal function*
Returns
-------
dict of categories -> indexers
Examples
--------
>>> c = pd.Categorical(list('aabca'))
>>> c
[a, a, b, c, a]
Categories (3, object): [a, b, c]
>>> c.categories
Index(['a', 'b', 'c'], dtype='object')
>>> c.codes
array([0, 0, 1, 2, 0], dtype=int8)
>>> c._reverse_indexer()
{'a': array([0, 1, 4]), 'b': array([2]), 'c': array([3])}
"""
categories = self.categories
r, counts = libalgos.groupsort_indexer(
self.codes.astype("int64"), categories.size
)
counts = counts.cumsum()
_result = (r[start:end] for start, end in zip(counts, counts[1:]))
result = dict(zip(categories, _result))
return result
# reduction ops #
def _reduce(self, name, axis=0, **kwargs):
func = getattr(self, name, None)
if func is None:
raise TypeError(f"Categorical cannot perform the operation {name}")
return func(**kwargs)
@deprecate_kwarg(old_arg_name="numeric_only", new_arg_name="skipna")
def min(self, skipna=True):
"""
The minimum value of the object.
Only ordered `Categoricals` have a minimum!
.. versionchanged:: 1.0.0
Returns an NA value on empty arrays
Raises
------
TypeError
If the `Categorical` is not `ordered`.
Returns
-------
min : the minimum of this `Categorical`
"""
self.check_for_ordered("min")
if not len(self._codes):
return self.dtype.na_value
good = self._codes != -1
if not good.all():
if skipna:
pointer = self._codes[good].min()
else:
return np.nan
else:
pointer = self._codes.min()
return self.categories[pointer]
@deprecate_kwarg(old_arg_name="numeric_only", new_arg_name="skipna")
def max(self, skipna=True):
"""
The maximum value of the object.
Only ordered `Categoricals` have a maximum!
.. versionchanged:: 1.0.0
Returns an NA value on empty arrays
Raises
------
TypeError
If the `Categorical` is not `ordered`.
Returns
-------
max : the maximum of this `Categorical`
"""
self.check_for_ordered("max")
if not len(self._codes):
return self.dtype.na_value
good = self._codes != -1
if not good.all():
if skipna:
pointer = self._codes[good].max()
else:
return np.nan
else:
pointer = self._codes.max()
return self.categories[pointer]
def mode(self, dropna=True):
"""
Returns the mode(s) of the Categorical.
Always returns `Categorical` even if only one value.
Parameters
----------
dropna : bool, default True
Don't consider counts of NaN/NaT.
.. versionadded:: 0.24.0
Returns
-------
modes : `Categorical` (sorted)
"""
codes = self._codes
if dropna:
good = self._codes != -1
codes = self._codes[good]
codes = sorted(htable.mode_int64(ensure_int64(codes), dropna))
return self._constructor(values=codes, dtype=self.dtype, fastpath=True)
def unique(self):
"""
Return the ``Categorical`` which ``categories`` and ``codes`` are
unique. Unused categories are NOT returned.
- unordered category: values and categories are sorted by appearance
order.
- ordered category: values are sorted by appearance order, categories
keeps existing order.
Returns
-------
unique values : ``Categorical``
Examples
--------
An unordered Categorical will return categories in the
order of appearance.
>>> pd.Categorical(list('baabc'))
[b, a, c]
Categories (3, object): [b, a, c]
>>> pd.Categorical(list('baabc'), categories=list('abc'))
[b, a, c]
Categories (3, object): [b, a, c]
An ordered Categorical preserves the category ordering.
>>> pd.Categorical(list('baabc'),
... categories=list('abc'),
... ordered=True)
[b, a, c]
Categories (3, object): [a < b < c]
See Also
--------
unique
CategoricalIndex.unique
Series.unique
"""
# unlike np.unique, unique1d does not sort
unique_codes = unique1d(self.codes)
cat = self.copy()
# keep nan in codes
cat._codes = unique_codes
# exclude nan from indexer for categories
take_codes = unique_codes[unique_codes != -1]
if self.ordered:
take_codes = np.sort(take_codes)
return cat.set_categories(cat.categories.take(take_codes))
def _values_for_factorize(self):
codes = self.codes.astype("int64")
return codes, -1
@classmethod
def _from_factorized(cls, uniques, original):
return original._constructor(
original.categories.take(uniques), dtype=original.dtype
)
def equals(self, other):
"""
Returns True if categorical arrays are equal.
Parameters
----------
other : `Categorical`
Returns
-------
bool
"""
if self.is_dtype_equal(other):
if self.categories.equals(other.categories):
# fastpath to avoid re-coding
other_codes = other._codes
else:
other_codes = _recode_for_categories(
other.codes, other.categories, self.categories
)
return np.array_equal(self._codes, other_codes)
return False
def is_dtype_equal(self, other):
"""
Returns True if categoricals are the same dtype
same categories, and same ordered
Parameters
----------
other : Categorical
Returns
-------
bool
"""
try:
return hash(self.dtype) == hash(other.dtype)
except (AttributeError, TypeError):
return False
def describe(self):
"""
Describes this Categorical
Returns
-------
description: `DataFrame`
A dataframe with frequency and counts by category.
"""
counts = self.value_counts(dropna=False)
freqs = counts / float(counts.sum())
from pandas.core.reshape.concat import concat
result = concat([counts, freqs], axis=1)
result.columns = ["counts", "freqs"]
result.index.name = "categories"
return result
@Substitution(klass="Categorical")
@Appender(_extension_array_shared_docs["repeat"])
def repeat(self, repeats, axis=None):
nv.validate_repeat(tuple(), dict(axis=axis))
codes = self._codes.repeat(repeats)
return self._constructor(values=codes, dtype=self.dtype, fastpath=True)
# Implement the ExtensionArray interface
@property
def _can_hold_na(self):
return True
@classmethod
def _concat_same_type(self, to_concat):
from pandas.core.dtypes.concat import concat_categorical
return concat_categorical(to_concat)
def isin(self, values):
"""
Check whether `values` are contained in Categorical.
Return a boolean NumPy Array showing whether each element in
the Categorical matches an element in the passed sequence of
`values` exactly.
Parameters
----------
values : set or list-like
The sequence of values to test. Passing in a single string will
raise a ``TypeError``. Instead, turn a single string into a
list of one element.
Returns
-------
isin : numpy.ndarray (bool dtype)
Raises
------
TypeError
* If `values` is not a set or list-like
See Also
--------
pandas.Series.isin : Equivalent method on Series.
Examples
--------
>>> s = pd.Categorical(['lama', 'cow', 'lama', 'beetle', 'lama',
... 'hippo'])
>>> s.isin(['cow', 'lama'])
array([ True, True, True, False, True, False])
Passing a single string as ``s.isin('lama')`` will raise an error. Use
a list of one element instead:
>>> s.isin(['lama'])
array([ True, False, True, False, True, False])
"""
if not is_list_like(values):
values_type = type(values).__name__
raise TypeError(
"only list-like objects are allowed to be passed "
f"to isin(), you passed a [{values_type}]"
)
values = sanitize_array(values, None, None)
null_mask = np.asarray(isna(values))
code_values = self.categories.get_indexer(values)
code_values = code_values[null_mask | (code_values >= 0)]
return algorithms.isin(self.codes, code_values)
def replace(self, to_replace, value, inplace: bool = False):
"""
Replaces all instances of one value with another
Parameters
----------
to_replace: object
The value to be replaced
value: object
The value to replace it with
inplace: bool
Whether the operation is done in-place
Returns
-------
None if inplace is True, otherwise the new Categorical after replacement
Examples
--------
>>> s = pd.Categorical([1, 2, 1, 3])
>>> s.replace(1, 3)
[3, 3, 2, 3]
Categories (2, int64): [2, 3]
"""
inplace = validate_bool_kwarg(inplace, "inplace")
cat = self if inplace else self.copy()
# build a dict of (to replace -> value) pairs
if is_list_like(to_replace):
# if to_replace is list-like and value is scalar
replace_dict = {replace_value: value for replace_value in to_replace}
else:
# if both to_replace and value are scalar
replace_dict = {to_replace: value}
# other cases, like if both to_replace and value are list-like or if
# to_replace is a dict, are handled separately in NDFrame
for replace_value, new_value in replace_dict.items():
if replace_value in cat.categories:
if isna(new_value):
cat.remove_categories(replace_value, inplace=True)
continue
categories = cat.categories.tolist()
index = categories.index(replace_value)
if new_value in cat.categories:
value_index = categories.index(new_value)
cat._codes[cat._codes == index] = value_index
cat.remove_categories(replace_value, inplace=True)
else:
categories[index] = new_value
cat.rename_categories(categories, inplace=True)
if not inplace:
return cat
# The Series.cat accessor
@delegate_names(
delegate=Categorical, accessors=["categories", "ordered"], typ="property"
)
@delegate_names(
delegate=Categorical,
accessors=[
"rename_categories",
"reorder_categories",
"add_categories",
"remove_categories",
"remove_unused_categories",
"set_categories",
"as_ordered",
"as_unordered",
],
typ="method",
)
class CategoricalAccessor(PandasDelegate, PandasObject, NoNewAttributesMixin):
"""
Accessor object for categorical properties of the Series values.
Be aware that assigning to `categories` is a inplace operation, while all
methods return new categorical data per default (but can be called with
`inplace=True`).
Parameters
----------
data : Series or CategoricalIndex
Examples
--------
>>> s.cat.categories
>>> s.cat.categories = list('abc')
>>> s.cat.rename_categories(list('cab'))
>>> s.cat.reorder_categories(list('cab'))
>>> s.cat.add_categories(['d','e'])
>>> s.cat.remove_categories(['d'])
>>> s.cat.remove_unused_categories()
>>> s.cat.set_categories(list('abcde'))
>>> s.cat.as_ordered()
>>> s.cat.as_unordered()
"""
def __init__(self, data):
self._validate(data)
self._parent = data.values
self._index = data.index
self._name = data.name
self._freeze()
@staticmethod
def _validate(data):
if not is_categorical_dtype(data.dtype):
raise AttributeError("Can only use .cat accessor with a 'category' dtype")
def _delegate_property_get(self, name):
return getattr(self._parent, name)
def _delegate_property_set(self, name, new_values):
return setattr(self._parent, name, new_values)
@property
def codes(self):
"""
Return Series of codes as well as the index.
"""
from pandas import Series
return Series(self._parent.codes, index=self._index)
def _delegate_method(self, name, *args, **kwargs):
from pandas import Series
method = getattr(self._parent, name)
res = method(*args, **kwargs)
if res is not None:
return Series(res, index=self._index, name=self._name)
# utility routines
def _get_codes_for_values(values, categories):
"""
utility routine to turn values into codes given the specified categories
"""
dtype_equal = is_dtype_equal(values.dtype, categories.dtype)
if dtype_equal:
# To prevent erroneous dtype coercion in _get_data_algo, retrieve
# the underlying numpy array. gh-22702
values = getattr(values, "_ndarray_values", values)
categories = getattr(categories, "_ndarray_values", categories)
elif is_extension_array_dtype(categories.dtype) and is_object_dtype(values):
# Support inferring the correct extension dtype from an array of
# scalar objects. e.g.
# Categorical(array[Period, Period], categories=PeriodIndex(...))
cls = categories.dtype.construct_array_type()
values = try_cast_to_ea(cls, values)
if not isinstance(values, cls):
# exception raised in _from_sequence
values = ensure_object(values)
categories = ensure_object(categories)
else:
values = ensure_object(values)
categories = ensure_object(categories)
hash_klass, vals = _get_data_algo(values)
_, cats = _get_data_algo(categories)
t = hash_klass(len(cats))
t.map_locations(cats)
return coerce_indexer_dtype(t.lookup(vals), cats)
def _recode_for_categories(codes: np.ndarray, old_categories, new_categories):
"""
Convert a set of codes for to a new set of categories
Parameters
----------
codes : np.ndarray
old_categories, new_categories : Index
Returns
-------
new_codes : np.ndarray[np.int64]
Examples
--------
>>> old_cat = pd.Index(['b', 'a', 'c'])
>>> new_cat = pd.Index(['a', 'b'])
>>> codes = np.array([0, 1, 1, 2])
>>> _recode_for_categories(codes, old_cat, new_cat)
array([ 1, 0, 0, -1])
"""
if len(old_categories) == 0:
# All null anyway, so just retain the nulls
return codes.copy()
elif new_categories.equals(old_categories):
# Same categories, so no need to actually recode
return codes.copy()
indexer = coerce_indexer_dtype(
new_categories.get_indexer(old_categories), new_categories
)
new_codes = take_1d(indexer, codes.copy(), fill_value=-1)
return new_codes
def _convert_to_list_like(list_like):
if hasattr(list_like, "dtype"):
return list_like
if isinstance(list_like, list):
return list_like
if is_sequence(list_like) or isinstance(list_like, tuple) or is_iterator(list_like):
return list(list_like)
elif is_scalar(list_like):
return [list_like]
else:
# TODO: is this reached?
return [list_like]
def factorize_from_iterable(values):
"""
Factorize an input `values` into `categories` and `codes`. Preserves
categorical dtype in `categories`.
*This is an internal function*
Parameters
----------
values : list-like
Returns
-------
codes : ndarray
categories : Index
If `values` has a categorical dtype, then `categories` is
a CategoricalIndex keeping the categories and order of `values`.
"""
if not is_list_like(values):
raise TypeError("Input must be list-like")
if is_categorical_dtype(values):
values = extract_array(values)
# The Categorical we want to build has the same categories
# as values but its codes are by def [0, ..., len(n_categories) - 1]
cat_codes = np.arange(len(values.categories), dtype=values.codes.dtype)
categories = Categorical.from_codes(cat_codes, dtype=values.dtype)
codes = values.codes
else:
# The value of ordered is irrelevant since we don't use cat as such,
# but only the resulting categories, the order of which is independent
# from ordered. Set ordered to False as default. See GH #15457
cat = Categorical(values, ordered=False)
categories = cat.categories
codes = cat.codes
return codes, categories
def factorize_from_iterables(iterables):
"""
A higher-level wrapper over `factorize_from_iterable`.
*This is an internal function*
Parameters
----------
iterables : list-like of list-likes
Returns
-------
codes_list : list of ndarrays
categories_list : list of Indexes
Notes
-----
See `factorize_from_iterable` for more info.
"""
if len(iterables) == 0:
# For consistency, it should return a list of 2 lists.
return [[], []]
return map(list, zip(*(factorize_from_iterable(it) for it in iterables)))
import operator
from shutil import get_terminal_size
from typing import Dict, Hashable, List, Type, Union, cast
from warnings import warn
import numpy as np
from pandas._config import get_option
from pandas._libs import algos as libalgos, hashtable as htable
from pandas._typing import ArrayLike, Dtype, Ordered, Scalar
from pandas.compat.numpy import function as nv
from pandas.util._decorators import (
Appender,
Substitution,
cache_readonly,
deprecate_kwarg,
)
from pandas.util._validators import validate_bool_kwarg, validate_fillna_kwargs
from pandas.core.dtypes.cast import coerce_indexer_dtype, maybe_infer_to_datetimelike
from pandas.core.dtypes.common import (
ensure_int64,
ensure_object,
ensure_platform_int,
is_categorical_dtype,
is_datetime64_dtype,
is_dict_like,
is_dtype_equal,
is_extension_array_dtype,
is_integer_dtype,
is_iterator,
is_list_like,
is_object_dtype,
is_scalar,
is_sequence,
is_timedelta64_dtype,
needs_i8_conversion,
)
from pandas.core.dtypes.dtypes import CategoricalDtype
from pandas.core.dtypes.generic import ABCIndexClass, ABCSeries
from pandas.core.dtypes.inference import is_hashable
from pandas.core.dtypes.missing import isna, notna
from pandas.core import ops
from pandas.core.accessor import PandasDelegate, delegate_names
import pandas.core.algorithms as algorithms
from pandas.core.algorithms import _get_data_algo, factorize, take, take_1d, unique1d
from pandas.core.arrays.base import (
ExtensionArray,
_extension_array_shared_docs,
try_cast_to_ea,
)
from pandas.core.base import NoNewAttributesMixin, PandasObject, _shared_docs
import pandas.core.common as com
from pandas.core.construction import array, extract_array, sanitize_array
from pandas.core.indexers import check_array_indexer, deprecate_ndim_indexing
from pandas.core.missing import interpolate_2d
from pandas.core.ops.common import unpack_zerodim_and_defer
from pandas.core.sorting import nargsort
from pandas.io.formats import console
def _cat_compare_op(op):
opname = f"__{op.__name__}__"
@unpack_zerodim_and_defer(opname)
def func(self, other):
if is_list_like(other) and len(other) != len(self):
# TODO: Could this fail if the categories are listlike objects?
raise ValueError("Lengths must match.")
if not self.ordered:
if opname in ["__lt__", "__gt__", "__le__", "__ge__"]:
raise TypeError(
"Unordered Categoricals can only compare equality or not"
)
if isinstance(other, Categorical):
# Two Categoricals can only be be compared if the categories are
# the same (maybe up to ordering, depending on ordered)
msg = "Categoricals can only be compared if 'categories' are the same."
if len(self.categories) != len(other.categories):
raise TypeError(msg + " Categories are different lengths")
elif self.ordered and not (self.categories == other.categories).all():
raise TypeError(msg)
elif not set(self.categories) == set(other.categories):
raise TypeError(msg)
if not (self.ordered == other.ordered):
raise TypeError(
"Categoricals can only be compared if 'ordered' is the same"
)
if not self.ordered and not self.categories.equals(other.categories):
# both unordered and different order
other_codes = _get_codes_for_values(other, self.categories)
else:
other_codes = other._codes
f = getattr(self._codes, opname)
ret = f(other_codes)
mask = (self._codes == -1) | (other_codes == -1)
if mask.any():
# In other series, the leads to False, so do that here too
if opname == "__ne__":
ret[(self._codes == -1) & (other_codes == -1)] = True
else:
ret[mask] = False
return ret
if is_scalar(other):
if other in self.categories:
i = self.categories.get_loc(other)
ret = getattr(self._codes, opname)(i)
if opname not in {"__eq__", "__ge__", "__gt__"}:
# check for NaN needed if we are not equal or larger
mask = self._codes == -1
ret[mask] = False
return ret
else:
if opname == "__eq__":
return np.zeros(len(self), dtype=bool)
elif opname == "__ne__":
return np.ones(len(self), dtype=bool)
else:
raise TypeError(
f"Cannot compare a Categorical for op {opname} with a "
"scalar, which is not a category."
)
else:
# allow categorical vs object dtype array comparisons for equality
# these are only positional comparisons
if opname in ["__eq__", "__ne__"]:
return getattr(np.array(self), opname)(np.array(other))
raise TypeError(
f"Cannot compare a Categorical for op {opname} with "
f"type {type(other)}.\nIf you want to compare values, "
"use 'np.asarray(cat) <op> other'."
)
func.__name__ = opname
return func
def contains(cat, key, container):
"""
Helper for membership check for ``key`` in ``cat``.
This is a helper method for :method:`__contains__`
and :class:`CategoricalIndex.__contains__`.
Returns True if ``key`` is in ``cat.categories`` and the
location of ``key`` in ``categories`` is in ``container``.
Parameters
----------
cat : :class:`Categorical`or :class:`categoricalIndex`
key : a hashable object
The key to check membership for.
container : Container (e.g. list-like or mapping)
The container to check for membership in.
Returns
-------
is_in : bool
True if ``key`` is in ``self.categories`` and location of
``key`` in ``categories`` is in ``container``, else False.
Notes
-----
This method does not check for NaN values. Do that separately
before calling this method.
"""
hash(key)
# get location of key in categories.
# If a KeyError, the key isn't in categories, so logically
# can't be in container either.
try:
loc = cat.categories.get_loc(key)
except (KeyError, TypeError):
return False
# loc is the location of key in categories, but also the *value*
# for key in container. So, `key` may be in categories,
# but still not in `container`. Example ('b' in categories,
# but not in values):
# 'b' in Categorical(['a'], categories=['a', 'b']) # False
if is_scalar(loc):
return loc in container
else:
# if categories is an IntervalIndex, loc is an array.
return any(loc_ in container for loc_ in loc)
_codes_doc = """
The category codes of this categorical.
Level codes are an array if integer which are the positions of the real
values in the categories array.
There is not setter, use the other categorical methods and the normal item
setter to change values in the categorical.
"""
class Categorical(ExtensionArray, PandasObject):
"""
Represent a categorical variable in classic R / S-plus fashion.
`Categoricals` can only take on only a limited, and usually fixed, number
of possible values (`categories`). In contrast to statistical categorical
variables, a `Categorical` might have an order, but numerical operations
(additions, divisions, ...) are not possible.
All values of the `Categorical` are either in `categories` or `np.nan`.
Assigning values outside of `categories` will raise a `ValueError`. Order
is defined by the order of the `categories`, not lexical order of the
values.
Parameters
----------
values : list-like
The values of the categorical. If categories are given, values not in
categories will be replaced with NaN.
categories : Index-like (unique), optional
The unique categories for this categorical. If not given, the
categories are assumed to be the unique values of `values` (sorted, if
possible, otherwise in the order in which they appear).
ordered : bool, default False
Whether or not this categorical is treated as a ordered categorical.
If True, the resulting categorical will be ordered.
An ordered categorical respects, when sorted, the order of its
`categories` attribute (which in turn is the `categories` argument, if
provided).
dtype : CategoricalDtype
An instance of ``CategoricalDtype`` to use for this categorical.
.. versionadded:: 0.21.0
Attributes
----------
categories : Index
The categories of this categorical
codes : ndarray
The codes (integer positions, which point to the categories) of this
categorical, read only.
ordered : bool
Whether or not this Categorical is ordered.
dtype : CategoricalDtype
The instance of ``CategoricalDtype`` storing the ``categories``
and ``ordered``.
.. versionadded:: 0.21.0
Methods
-------
from_codes
__array__
Raises
------
ValueError
If the categories do not validate.
TypeError
If an explicit ``ordered=True`` is given but no `categories` and the
`values` are not sortable.
See Also
--------
CategoricalDtype : Type for categorical data.
CategoricalIndex : An Index with an underlying ``Categorical``.
Notes
-----
See the `user guide
<https://pandas.pydata.org/pandas-docs/stable/user_guide/categorical.html>`_
for more.
Examples
--------
>>> pd.Categorical([1, 2, 3, 1, 2, 3])
[1, 2, 3, 1, 2, 3]
Categories (3, int64): [1, 2, 3]
>>> pd.Categorical(['a', 'b', 'c', 'a', 'b', 'c'])
[a, b, c, a, b, c]
Categories (3, object): [a, b, c]
Ordered `Categoricals` can be sorted according to the custom order
of the categories and can have a min and max value.
>>> c = pd.Categorical(['a', 'b', 'c', 'a', 'b', 'c'], ordered=True,
... categories=['c', 'b', 'a'])
>>> c
[a, b, c, a, b, c]
Categories (3, object): [c < b < a]
>>> c.min()
'c'
"""
# For comparisons, so that numpy uses our implementation if the compare
# ops, which raise
__array_priority__ = 1000
_dtype = CategoricalDtype(ordered=False)
# tolist is not actually deprecated, just suppressed in the __dir__
_deprecations = PandasObject._deprecations | frozenset(["tolist"])
_typ = "categorical"
def __init__(
self, values, categories=None, ordered=None, dtype=None, fastpath=False
):
dtype = CategoricalDtype._from_values_or_dtype(
values, categories, ordered, dtype
)
# At this point, dtype is always a CategoricalDtype, but
# we may have dtype.categories be None, and we need to
# infer categories in a factorization step further below
if fastpath:
self._codes = coerce_indexer_dtype(values, dtype.categories)
self._dtype = self._dtype.update_dtype(dtype)
return
# null_mask indicates missing values we want to exclude from inference.
# This means: only missing values in list-likes (not arrays/ndframes).
null_mask = np.array(False)
# sanitize input
if is_categorical_dtype(values):
if dtype.categories is None:
dtype = CategoricalDtype(values.categories, dtype.ordered)
elif not isinstance(values, (ABCIndexClass, ABCSeries)):
# sanitize_array coerces np.nan to a string under certain versions
# of numpy
values = maybe_infer_to_datetimelike(values, convert_dates=True)
if not isinstance(values, np.ndarray):
values = _convert_to_list_like(values)
# By convention, empty lists result in object dtype:
sanitize_dtype = "object" if len(values) == 0 else None
null_mask = isna(values)
if null_mask.any():
values = [values[idx] for idx in np.where(~null_mask)[0]]
values = sanitize_array(values, None, dtype=sanitize_dtype)
if dtype.categories is None:
try:
codes, categories = factorize(values, sort=True)
except TypeError as err:
codes, categories = factorize(values, sort=False)
if dtype.ordered:
# raise, as we don't have a sortable data structure and so
# the user should give us one by specifying categories
raise TypeError(
"'values' is not ordered, please "
"explicitly specify the categories order "
"by passing in a categories argument."
) from err
except ValueError as err:
# FIXME
raise NotImplementedError(
"> 1 ndim Categorical are not supported at this time"
) from err
# we're inferring from values
dtype = CategoricalDtype(categories, dtype.ordered)
elif is_categorical_dtype(values):
old_codes = (
values._values.codes if isinstance(values, ABCSeries) else values.codes
)
codes = _recode_for_categories(
old_codes, values.dtype.categories, dtype.categories
)
else:
codes = _get_codes_for_values(values, dtype.categories)
if null_mask.any():
# Reinsert -1 placeholders for previously removed missing values
full_codes = -np.ones(null_mask.shape, dtype=codes.dtype)
full_codes[~null_mask] = codes
codes = full_codes
self._dtype = self._dtype.update_dtype(dtype)
self._codes = coerce_indexer_dtype(codes, dtype.categories)
@property
def categories(self):
"""
The categories of this categorical.
Setting assigns new values to each category (effectively a rename of
each individual category).
The assigned value has to be a list-like object. All items must be
unique and the number of items in the new categories must be the same
as the number of items in the old categories.
Assigning to `categories` is a inplace operation!
Raises
------
ValueError
If the new categories do not validate as categories or if the
number of new categories is unequal the number of old categories
See Also
--------
rename_categories
reorder_categories
add_categories
remove_categories
remove_unused_categories
set_categories
"""
return self.dtype.categories
@categories.setter
def categories(self, categories):
new_dtype = CategoricalDtype(categories, ordered=self.ordered)
if self.dtype.categories is not None and len(self.dtype.categories) != len(
new_dtype.categories
):
raise ValueError(
"new categories need to have the same number of "
"items as the old categories!"
)
self._dtype = new_dtype
@property
def ordered(self) -> Ordered:
"""
Whether the categories have an ordered relationship.
"""
return self.dtype.ordered
@property
def dtype(self) -> CategoricalDtype:
"""
The :class:`~pandas.api.types.CategoricalDtype` for this instance.
"""
return self._dtype
@property
def _ndarray_values(self) -> np.ndarray:
return self.codes
@property
def _constructor(self) -> Type["Categorical"]:
return Categorical
@classmethod
def _from_sequence(cls, scalars, dtype=None, copy=False):
return Categorical(scalars, dtype=dtype)
def _formatter(self, boxed=False):
# Defer to CategoricalFormatter's formatter.
return None
def copy(self) -> "Categorical":
"""
Copy constructor.
"""
return self._constructor(
values=self._codes.copy(), dtype=self.dtype, fastpath=True
)
def astype(self, dtype: Dtype, copy: bool = True) -> ArrayLike:
"""
Coerce this type to another dtype
Parameters
----------
dtype : numpy dtype or pandas type
copy : bool, default True
By default, astype always returns a newly allocated object.
If copy is set to False and dtype is categorical, the original
object is returned.
"""
if is_categorical_dtype(dtype):
dtype = cast(Union[str, CategoricalDtype], dtype)
# GH 10696/18593
dtype = self.dtype.update_dtype(dtype)
self = self.copy() if copy else self
if dtype == self.dtype:
return self
return self._set_dtype(dtype)
if is_extension_array_dtype(dtype):
return array(self, dtype=dtype, copy=copy) # type: ignore # GH 28770
if is_integer_dtype(dtype) and self.isna().any():
raise ValueError("Cannot convert float NaN to integer")
return np.array(self, dtype=dtype, copy=copy)
@cache_readonly
def size(self) -> int:
"""
Return the len of myself.
"""
return self._codes.size
@cache_readonly
def itemsize(self) -> int:
"""
return the size of a single category
"""
return self.categories.itemsize
def tolist(self) -> List[Scalar]:
"""
Return a list of the values.
These are each a scalar type, which is a Python scalar
(for str, int, float) or a pandas scalar
(for Timestamp/Timedelta/Interval/Period)
"""
return list(self)
to_list = tolist
@classmethod
def _from_inferred_categories(
cls, inferred_categories, inferred_codes, dtype, true_values=None
):
"""
Construct a Categorical from inferred values.
For inferred categories (`dtype` is None) the categories are sorted.
For explicit `dtype`, the `inferred_categories` are cast to the
appropriate type.
Parameters
----------
inferred_categories : Index
inferred_codes : Index
dtype : CategoricalDtype or 'category'
true_values : list, optional
If none are provided, the default ones are
"True", "TRUE", and "true."
Returns
-------
Categorical
"""
from pandas import Index, to_numeric, to_datetime, to_timedelta
cats = Index(inferred_categories)
known_categories = (
isinstance(dtype, CategoricalDtype) and dtype.categories is not None
)
if known_categories:
# Convert to a specialized type with `dtype` if specified.
if dtype.categories.is_numeric():
cats = to_numeric(inferred_categories, errors="coerce")
elif is_datetime64_dtype(dtype.categories):
cats = to_datetime(inferred_categories, errors="coerce")
elif is_timedelta64_dtype(dtype.categories):
cats = to_timedelta(inferred_categories, errors="coerce")
elif dtype.categories.is_boolean():
if true_values is None:
true_values = ["True", "TRUE", "true"]
cats = cats.isin(true_values)
if known_categories:
# Recode from observation order to dtype.categories order.
categories = dtype.categories
codes = _recode_for_categories(inferred_codes, cats, categories)
elif not cats.is_monotonic_increasing:
# Sort categories and recode for unknown categories.
unsorted = cats.copy()
categories = cats.sort_values()
codes = _recode_for_categories(inferred_codes, unsorted, categories)
dtype = CategoricalDtype(categories, ordered=False)
else:
dtype = CategoricalDtype(cats, ordered=False)
codes = inferred_codes
return cls(codes, dtype=dtype, fastpath=True)
@classmethod
def from_codes(cls, codes, categories=None, ordered=None, dtype=None):
"""
Make a Categorical type from codes and categories or dtype.
This constructor is useful if you already have codes and
categories/dtype and so do not need the (computation intensive)
factorization step, which is usually done on the constructor.
If your data does not follow this convention, please use the normal
constructor.
Parameters
----------
codes : array-like of int
An integer array, where each integer points to a category in
categories or dtype.categories, or else is -1 for NaN.
categories : index-like, optional
The categories for the categorical. Items need to be unique.
If the categories are not given here, then they must be provided
in `dtype`.
ordered : bool, optional
Whether or not this categorical is treated as an ordered
categorical. If not given here or in `dtype`, the resulting
categorical will be unordered.
dtype : CategoricalDtype or "category", optional
If :class:`CategoricalDtype`, cannot be used together with
`categories` or `ordered`.
.. versionadded:: 0.24.0
When `dtype` is provided, neither `categories` nor `ordered`
should be provided.
Returns
-------
Categorical
Examples
--------
>>> dtype = pd.CategoricalDtype(['a', 'b'], ordered=True)
>>> pd.Categorical.from_codes(codes=[0, 1, 0, 1], dtype=dtype)
[a, b, a, b]
Categories (2, object): [a < b]
"""
dtype = CategoricalDtype._from_values_or_dtype(
categories=categories, ordered=ordered, dtype=dtype
)
if dtype.categories is None:
msg = (
"The categories must be provided in 'categories' or "
"'dtype'. Both were None."
)
raise ValueError(msg)
if is_extension_array_dtype(codes) and is_integer_dtype(codes):
# Avoid the implicit conversion of Int to object
if isna(codes).any():
raise ValueError("codes cannot contain NA values")
codes = codes.to_numpy(dtype=np.int64)
else:
codes = np.asarray(codes)
if len(codes) and not is_integer_dtype(codes):
raise ValueError("codes need to be array-like integers")
if len(codes) and (codes.max() >= len(dtype.categories) or codes.min() < -1):
raise ValueError("codes need to be between -1 and len(categories)-1")
return cls(codes, dtype=dtype, fastpath=True)
def _get_codes(self):
"""
Get the codes.
Returns
-------
codes : integer array view
A non writable view of the `codes` array.
"""
v = self._codes.view()
v.flags.writeable = False
return v
def _set_codes(self, codes):
"""
Not settable by the user directly
"""
raise ValueError("cannot set Categorical codes directly")
codes = property(fget=_get_codes, fset=_set_codes, doc=_codes_doc)
def _set_categories(self, categories, fastpath=False):
"""
Sets new categories inplace
Parameters
----------
fastpath : bool, default False
Don't perform validation of the categories for uniqueness or nulls
Examples
--------
>>> c = pd.Categorical(['a', 'b'])
>>> c
[a, b]
Categories (2, object): [a, b]
>>> c._set_categories(pd.Index(['a', 'c']))
>>> c
[a, c]
Categories (2, object): [a, c]
"""
if fastpath:
new_dtype = CategoricalDtype._from_fastpath(categories, self.ordered)
else:
new_dtype = CategoricalDtype(categories, ordered=self.ordered)
if (
not fastpath
and self.dtype.categories is not None
and len(new_dtype.categories) != len(self.dtype.categories)
):
raise ValueError(
"new categories need to have the same number of "
"items than the old categories!"
)
self._dtype = new_dtype
def _set_dtype(self, dtype: CategoricalDtype) -> "Categorical":
"""
Internal method for directly updating the CategoricalDtype
Parameters
----------
dtype : CategoricalDtype
Notes
-----
We don't do any validation here. It's assumed that the dtype is
a (valid) instance of `CategoricalDtype`.
"""
codes = _recode_for_categories(self.codes, self.categories, dtype.categories)
return type(self)(codes, dtype=dtype, fastpath=True)
def set_ordered(self, value, inplace=False):
"""
Set the ordered attribute to the boolean value.
Parameters
----------
value : bool
Set whether this categorical is ordered (True) or not (False).
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to the value.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
new_dtype = CategoricalDtype(self.categories, ordered=value)
cat = self if inplace else self.copy()
cat._dtype = new_dtype
if not inplace:
return cat
def as_ordered(self, inplace=False):
"""
Set the Categorical to be ordered.
Parameters
----------
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to True.
Returns
-------
Categorical
Ordered Categorical.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
return self.set_ordered(True, inplace=inplace)
def as_unordered(self, inplace=False):
"""
Set the Categorical to be unordered.
Parameters
----------
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to False.
Returns
-------
Categorical
Unordered Categorical.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
return self.set_ordered(False, inplace=inplace)
def set_categories(self, new_categories, ordered=None, rename=False, inplace=False):
"""
Set the categories to the specified new_categories.
`new_categories` can include new categories (which will result in
unused categories) or remove old categories (which results in values
set to NaN). If `rename==True`, the categories will simple be renamed
(less or more items than in old categories will result in values set to
NaN or in unused categories respectively).
This method can be used to perform more than one action of adding,
removing, and reordering simultaneously and is therefore faster than
performing the individual steps via the more specialised methods.
On the other hand this methods does not do checks (e.g., whether the
old categories are included in the new categories on a reorder), which
can result in surprising changes, for example when using special string
dtypes, which does not considers a S1 string equal to a single char
python string.
Parameters
----------
new_categories : Index-like
The categories in new order.
ordered : bool, default False
Whether or not the categorical is treated as a ordered categorical.
If not given, do not change the ordered information.
rename : bool, default False
Whether or not the new_categories should be considered as a rename
of the old categories or as reordered categories.
inplace : bool, default False
Whether or not to reorder the categories in-place or return a copy
of this categorical with reordered categories.
Returns
-------
Categorical with reordered categories or None if inplace.
Raises
------
ValueError
If new_categories does not validate as categories
See Also
--------
rename_categories
reorder_categories
add_categories
remove_categories
remove_unused_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if ordered is None:
ordered = self.dtype.ordered
new_dtype = CategoricalDtype(new_categories, ordered=ordered)
cat = self if inplace else self.copy()
if rename:
if cat.dtype.categories is not None and len(new_dtype.categories) < len(
cat.dtype.categories
):
# remove all _codes which are larger and set to -1/NaN
cat._codes[cat._codes >= len(new_dtype.categories)] = -1
else:
codes = _recode_for_categories(
cat.codes, cat.categories, new_dtype.categories
)
cat._codes = codes
cat._dtype = new_dtype
if not inplace:
return cat
def rename_categories(self, new_categories, inplace=False):
"""
Rename categories.
Parameters
----------
new_categories : list-like, dict-like or callable
New categories which will replace old categories.
* list-like: all items must be unique and the number of items in
the new categories must match the existing number of categories.
* dict-like: specifies a mapping from
old categories to new. Categories not contained in the mapping
are passed through and extra categories in the mapping are
ignored.
.. versionadded:: 0.21.0.
* callable : a callable that is called on all items in the old
categories and whose return values comprise the new categories.
.. versionadded:: 0.23.0.
inplace : bool, default False
Whether or not to rename the categories inplace or return a copy of
this categorical with renamed categories.
Returns
-------
cat : Categorical or None
With ``inplace=False``, the new categorical is returned.
With ``inplace=True``, there is no return value.
Raises
------
ValueError
If new categories are list-like and do not have the same number of
items than the current categories or do not validate as categories
See Also
--------
reorder_categories
add_categories
remove_categories
remove_unused_categories
set_categories
Examples
--------
>>> c = pd.Categorical(['a', 'a', 'b'])
>>> c.rename_categories([0, 1])
[0, 0, 1]
Categories (2, int64): [0, 1]
For dict-like ``new_categories``, extra keys are ignored and
categories not in the dictionary are passed through
>>> c.rename_categories({'a': 'A', 'c': 'C'})
[A, A, b]
Categories (2, object): [A, b]
You may also provide a callable to create the new categories
>>> c.rename_categories(lambda x: x.upper())
[A, A, B]
Categories (2, object): [A, B]
"""
inplace = validate_bool_kwarg(inplace, "inplace")
cat = self if inplace else self.copy()
if is_dict_like(new_categories):
cat.categories = [new_categories.get(item, item) for item in cat.categories]
elif callable(new_categories):
cat.categories = [new_categories(item) for item in cat.categories]
else:
cat.categories = new_categories
if not inplace:
return cat
def reorder_categories(self, new_categories, ordered=None, inplace=False):
"""
Reorder categories as specified in new_categories.
`new_categories` need to include all old categories and no new category
items.
Parameters
----------
new_categories : Index-like
The categories in new order.
ordered : bool, optional
Whether or not the categorical is treated as a ordered categorical.
If not given, do not change the ordered information.
inplace : bool, default False
Whether or not to reorder the categories inplace or return a copy of
this categorical with reordered categories.
Returns
-------
cat : Categorical with reordered categories or None if inplace.
Raises
------
ValueError
If the new categories do not contain all old category items or any
new ones
See Also
--------
rename_categories
add_categories
remove_categories
remove_unused_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if set(self.dtype.categories) != set(new_categories):
raise ValueError(
"items in new_categories are not the same as in old categories"
)
return self.set_categories(new_categories, ordered=ordered, inplace=inplace)
def add_categories(self, new_categories, inplace=False):
"""
Add new categories.
`new_categories` will be included at the last/highest place in the
categories and will be unused directly after this call.
Parameters
----------
new_categories : category or list-like of category
The new categories to be included.
inplace : bool, default False
Whether or not to add the categories inplace or return a copy of
this categorical with added categories.
Returns
-------
cat : Categorical with new categories added or None if inplace.
Raises
------
ValueError
If the new categories include old categories or do not validate as
categories
See Also
--------
rename_categories
reorder_categories
remove_categories
remove_unused_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not is_list_like(new_categories):
new_categories = [new_categories]
already_included = set(new_categories) & set(self.dtype.categories)
if len(already_included) != 0:
raise ValueError(
f"new categories must not include old categories: {already_included}"
)
new_categories = list(self.dtype.categories) + list(new_categories)
new_dtype = CategoricalDtype(new_categories, self.ordered)
cat = self if inplace else self.copy()
cat._dtype = new_dtype
cat._codes = coerce_indexer_dtype(cat._codes, new_dtype.categories)
if not inplace:
return cat
def remove_categories(self, removals, inplace=False):
"""
Remove the specified categories.
`removals` must be included in the old categories. Values which were in
the removed categories will be set to NaN
Parameters
----------
removals : category or list of categories
The categories which should be removed.
inplace : bool, default False
Whether or not to remove the categories inplace or return a copy of
this categorical with removed categories.
Returns
-------
cat : Categorical with removed categories or None if inplace.
Raises
------
ValueError
If the removals are not contained in the categories
See Also
--------
rename_categories
reorder_categories
add_categories
remove_unused_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not is_list_like(removals):
removals = [removals]
removal_set = set(removals)
not_included = removal_set - set(self.dtype.categories)
new_categories = [c for c in self.dtype.categories if c not in removal_set]
# GH 10156
if any(isna(removals)):
not_included = {x for x in not_included if notna(x)}
new_categories = [x for x in new_categories if notna(x)]
if len(not_included) != 0:
raise ValueError(f"removals must all be in old categories: {not_included}")
return self.set_categories(
new_categories, ordered=self.ordered, rename=False, inplace=inplace
)
def remove_unused_categories(self, inplace=False):
"""
Remove categories which are not used.
Parameters
----------
inplace : bool, default False
Whether or not to drop unused categories inplace or return a copy of
this categorical with unused categories dropped.
Returns
-------
cat : Categorical with unused categories dropped or None if inplace.
See Also
--------
rename_categories
reorder_categories
add_categories
remove_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
cat = self if inplace else self.copy()
idx, inv = np.unique(cat._codes, return_inverse=True)
if idx.size != 0 and idx[0] == -1: # na sentinel
idx, inv = idx[1:], inv - 1
new_categories = cat.dtype.categories.take(idx)
new_dtype = CategoricalDtype._from_fastpath(
new_categories, ordered=self.ordered
)
cat._dtype = new_dtype
cat._codes = coerce_indexer_dtype(inv, new_dtype.categories)
if not inplace:
return cat
def map(self, mapper):
"""
Map categories using input correspondence (dict, Series, or function).
Maps the categories to new categories. If the mapping correspondence is
one-to-one the result is a :class:`~pandas.Categorical` which has the
same order property as the original, otherwise a :class:`~pandas.Index`
is returned. NaN values are unaffected.
If a `dict` or :class:`~pandas.Series` is used any unmapped category is
mapped to `NaN`. Note that if this happens an :class:`~pandas.Index`
will be returned.
Parameters
----------
mapper : function, dict, or Series
Mapping correspondence.
Returns
-------
pandas.Categorical or pandas.Index
Mapped categorical.
See Also
--------
CategoricalIndex.map : Apply a mapping correspondence on a
:class:`~pandas.CategoricalIndex`.
Index.map : Apply a mapping correspondence on an
:class:`~pandas.Index`.
Series.map : Apply a mapping correspondence on a
:class:`~pandas.Series`.
Series.apply : Apply more complex functions on a
:class:`~pandas.Series`.
Examples
--------
>>> cat = pd.Categorical(['a', 'b', 'c'])
>>> cat
[a, b, c]
Categories (3, object): [a, b, c]
>>> cat.map(lambda x: x.upper())
[A, B, C]
Categories (3, object): [A, B, C]
>>> cat.map({'a': 'first', 'b': 'second', 'c': 'third'})
[first, second, third]
Categories (3, object): [first, second, third]
If the mapping is one-to-one the ordering of the categories is
preserved:
>>> cat = pd.Categorical(['a', 'b', 'c'], ordered=True)
>>> cat
[a, b, c]
Categories (3, object): [a < b < c]
>>> cat.map({'a': 3, 'b': 2, 'c': 1})
[3, 2, 1]
Categories (3, int64): [3 < 2 < 1]
If the mapping is not one-to-one an :class:`~pandas.Index` is returned:
>>> cat.map({'a': 'first', 'b': 'second', 'c': 'first'})
Index(['first', 'second', 'first'], dtype='object')
If a `dict` is used, all unmapped categories are mapped to `NaN` and
the result is an :class:`~pandas.Index`:
>>> cat.map({'a': 'first', 'b': 'second'})
Index(['first', 'second', nan], dtype='object')
"""
new_categories = self.categories.map(mapper)
try:
return self.from_codes(
self._codes.copy(), categories=new_categories, ordered=self.ordered
)
except ValueError:
# NA values are represented in self._codes with -1
# np.take causes NA values to take final element in new_categories
if np.any(self._codes == -1):
new_categories = new_categories.insert(len(new_categories), np.nan)
return np.take(new_categories, self._codes)
__eq__ = _cat_compare_op(operator.eq)
__ne__ = _cat_compare_op(operator.ne)
__lt__ = _cat_compare_op(operator.lt)
__gt__ = _cat_compare_op(operator.gt)
__le__ = _cat_compare_op(operator.le)
__ge__ = _cat_compare_op(operator.ge)
# for Series/ndarray like compat
@property
def shape(self):
"""
Shape of the Categorical.
For internal compatibility with numpy arrays.
Returns
-------
shape : tuple
"""
return tuple([len(self._codes)])
def shift(self, periods, fill_value=None):
"""
Shift Categorical by desired number of periods.
Parameters
----------
periods : int
Number of periods to move, can be positive or negative
fill_value : object, optional
The scalar value to use for newly introduced missing values.
.. versionadded:: 0.24.0
Returns
-------
shifted : Categorical
"""
# since categoricals always have ndim == 1, an axis parameter
# doesn't make any sense here.
codes = self.codes
if codes.ndim > 1:
raise NotImplementedError("Categorical with ndim > 1.")
if np.prod(codes.shape) and (periods != 0):
codes = np.roll(codes, ensure_platform_int(periods), axis=0)
if isna(fill_value):
fill_value = -1
elif fill_value in self.categories:
fill_value = self.categories.get_loc(fill_value)
else:
raise ValueError(
f"'fill_value={fill_value}' is not present "
"in this Categorical's categories"
)
if periods > 0:
codes[:periods] = fill_value
else:
codes[periods:] = fill_value
return self.from_codes(codes, dtype=self.dtype)
def __array__(self, dtype=None) -> np.ndarray:
"""
The numpy array interface.
Returns
-------
numpy.array
A numpy array of either the specified dtype or,
if dtype==None (default), the same dtype as
categorical.categories.dtype.
"""
ret = take_1d(self.categories.values, self._codes)
if dtype and not is_dtype_equal(dtype, self.categories.dtype):
return np.asarray(ret, dtype)
if is_extension_array_dtype(ret):
# When we're a Categorical[ExtensionArray], like Interval,
# we need to ensure __array__ get's all the way to an
# ndarray.
ret = np.asarray(ret)
return ret
def __array_ufunc__(self, ufunc, method, *inputs, **kwargs):
# for binary ops, use our custom dunder methods
result = ops.maybe_dispatch_ufunc_to_dunder_op(
self, ufunc, method, *inputs, **kwargs
)
if result is not NotImplemented:
return result
# for all other cases, raise for now (similarly as what happens in
# Series.__array_prepare__)
raise TypeError(
f"Object with dtype {self.dtype} cannot perform "
f"the numpy op {ufunc.__name__}"
)
def __setstate__(self, state):
"""Necessary for making this object picklable"""
if not isinstance(state, dict):
raise Exception("invalid pickle state")
# compat with pre 0.21.0 CategoricalDtype change
if "_dtype" not in state:
state["_dtype"] = CategoricalDtype(state["_categories"], state["_ordered"])
for k, v in state.items():
setattr(self, k, v)
@property
def T(self):
"""
Return transposed numpy array.
"""
return self
@property
def nbytes(self):
return self._codes.nbytes + self.dtype.categories.values.nbytes
def memory_usage(self, deep=False):
"""
Memory usage of my values
Parameters
----------
deep : bool
Introspect the data deeply, interrogate
`object` dtypes for system-level memory consumption
Returns
-------
bytes used
Notes
-----
Memory usage does not include memory consumed by elements that
are not components of the array if deep=False
See Also
--------
numpy.ndarray.nbytes
"""
return self._codes.nbytes + self.dtype.categories.memory_usage(deep=deep)
@Substitution(klass="Categorical")
@Appender(_shared_docs["searchsorted"])
def searchsorted(self, value, side="left", sorter=None):
# searchsorted is very performance sensitive. By converting codes
# to same dtype as self.codes, we get much faster performance.
if is_scalar(value):
codes = self.categories.get_loc(value)
codes = self.codes.dtype.type(codes)
else:
locs = [self.categories.get_loc(x) for x in value]
codes = np.array(locs, dtype=self.codes.dtype)
return self.codes.searchsorted(codes, side=side, sorter=sorter)
def isna(self):
"""
Detect missing values
Missing values (-1 in .codes) are detected.
Returns
-------
a boolean array of whether my values are null
See Also
--------
isna : Top-level isna.
isnull : Alias of isna.
Categorical.notna : Boolean inverse of Categorical.isna.
"""
ret = self._codes == -1
return ret
isnull = isna
def notna(self):
"""
Inverse of isna
Both missing values (-1 in .codes) and NA as a category are detected as
null.
Returns
-------
a boolean array of whether my values are not null
See Also
--------
notna : Top-level notna.
notnull : Alias of notna.
Categorical.isna : Boolean inverse of Categorical.notna.
"""
return ~self.isna()
notnull = notna
def put(self, *args, **kwargs):
"""
Replace specific elements in the Categorical with given values.
"""
raise NotImplementedError(("'put' is not yet implemented for Categorical"))
def dropna(self):
"""
Return the Categorical without null values.
Missing values (-1 in .codes) are detected.
Returns
-------
valid : Categorical
"""
result = self[self.notna()]
return result
def value_counts(self, dropna=True):
"""
Return a Series containing counts of each category.
Every category will have an entry, even those with a count of 0.
Parameters
----------
dropna : bool, default True
Don't include counts of NaN.
Returns
-------
counts : Series
See Also
--------
Series.value_counts
"""
from pandas import Series, CategoricalIndex
code, cat = self._codes, self.categories
ncat, mask = len(cat), 0 <= code
ix, clean = np.arange(ncat), mask.all()
if dropna or clean:
obs = code if clean else code[mask]
count = np.bincount(obs, minlength=ncat or 0)
else:
count = np.bincount(np.where(mask, code, ncat))
ix = np.append(ix, -1)
ix = self._constructor(ix, dtype=self.dtype, fastpath=True)
return Series(count, index=CategoricalIndex(ix), dtype="int64")
def _internal_get_values(self):
"""
Return the values.
For internal compatibility with pandas formatting.
Returns
-------
np.ndarray or Index
A numpy array of the same dtype as categorical.categories.dtype or
Index if datetime / periods.
"""
# if we are a datetime and period index, return Index to keep metadata
if needs_i8_conversion(self.categories):
return self.categories.take(self._codes, fill_value=np.nan)
elif is_integer_dtype(self.categories) and -1 in self._codes:
return self.categories.astype("object").take(self._codes, fill_value=np.nan)
return np.array(self)
def check_for_ordered(self, op):
""" assert that we are ordered """
if not self.ordered:
raise TypeError(
f"Categorical is not ordered for operation {op}\n"
"you can use .as_ordered() to change the "
"Categorical to an ordered one\n"
)
def _values_for_argsort(self):
return self._codes.copy()
def argsort(self, ascending=True, kind="quicksort", **kwargs):
"""
Return the indices that would sort the Categorical.
.. versionchanged:: 0.25.0
Changed to sort missing values at the end.
Parameters
----------
ascending : bool, default True
Whether the indices should result in an ascending
or descending sort.
kind : {'quicksort', 'mergesort', 'heapsort'}, optional
Sorting algorithm.
**kwargs:
passed through to :func:`numpy.argsort`.
Returns
-------
numpy.array
See Also
--------
numpy.ndarray.argsort
Notes
-----
While an ordering is applied to the category values, arg-sorting
in this context refers more to organizing and grouping together
based on matching category values. Thus, this function can be
called on an unordered Categorical instance unlike the functions
'Categorical.min' and 'Categorical.max'.
Examples
--------
>>> pd.Categorical(['b', 'b', 'a', 'c']).argsort()
array([2, 0, 1, 3])
>>> cat = pd.Categorical(['b', 'b', 'a', 'c'],
... categories=['c', 'b', 'a'],
... ordered=True)
>>> cat.argsort()
array([3, 0, 1, 2])
Missing values are placed at the end
>>> cat = pd.Categorical([2, None, 1])
>>> cat.argsort()
array([2, 0, 1])
"""
return super().argsort(ascending=ascending, kind=kind, **kwargs)
def sort_values(self, inplace=False, ascending=True, na_position="last"):
"""
Sort the Categorical by category value returning a new
Categorical by default.
While an ordering is applied to the category values, sorting in this
context refers more to organizing and grouping together based on
matching category values. Thus, this function can be called on an
unordered Categorical instance unlike the functions 'Categorical.min'
and 'Categorical.max'.
Parameters
----------
inplace : bool, default False
Do operation in place.
ascending : bool, default True
Order ascending. Passing False orders descending. The
ordering parameter provides the method by which the
category values are organized.
na_position : {'first', 'last'} (optional, default='last')
'first' puts NaNs at the beginning
'last' puts NaNs at the end
Returns
-------
Categorical or None
See Also
--------
Categorical.sort
Series.sort_values
Examples
--------
>>> c = pd.Categorical([1, 2, 2, 1, 5])
>>> c
[1, 2, 2, 1, 5]
Categories (3, int64): [1, 2, 5]
>>> c.sort_values()
[1, 1, 2, 2, 5]
Categories (3, int64): [1, 2, 5]
>>> c.sort_values(ascending=False)
[5, 2, 2, 1, 1]
Categories (3, int64): [1, 2, 5]
Inplace sorting can be done as well:
>>> c.sort_values(inplace=True)
>>> c
[1, 1, 2, 2, 5]
Categories (3, int64): [1, 2, 5]
>>>
>>> c = pd.Categorical([1, 2, 2, 1, 5])
'sort_values' behaviour with NaNs. Note that 'na_position'
is independent of the 'ascending' parameter:
>>> c = pd.Categorical([np.nan, 2, 2, np.nan, 5])
>>> c
[NaN, 2.0, 2.0, NaN, 5.0]
Categories (2, int64): [2, 5]
>>> c.sort_values()
[2.0, 2.0, 5.0, NaN, NaN]
Categories (2, int64): [2, 5]
>>> c.sort_values(ascending=False)
[5.0, 2.0, 2.0, NaN, NaN]
Categories (2, int64): [2, 5]
>>> c.sort_values(na_position='first')
[NaN, NaN, 2.0, 2.0, 5.0]
Categories (2, int64): [2, 5]
>>> c.sort_values(ascending=False, na_position='first')
[NaN, NaN, 5.0, 2.0, 2.0]
Categories (2, int64): [2, 5]
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if na_position not in ["last", "first"]:
raise ValueError(f"invalid na_position: {repr(na_position)}")
sorted_idx = nargsort(self, ascending=ascending, na_position=na_position)
if inplace:
self._codes = self._codes[sorted_idx]
else:
return self._constructor(
values=self._codes[sorted_idx], dtype=self.dtype, fastpath=True
)
def _values_for_rank(self):
"""
For correctly ranking ordered categorical data. See GH#15420
Ordered categorical data should be ranked on the basis of
codes with -1 translated to NaN.
Returns
-------
numpy.array
"""
from pandas import Series
if self.ordered:
values = self.codes
mask = values == -1
if mask.any():
values = values.astype("float64")
values[mask] = np.nan
elif self.categories.is_numeric():
values = np.array(self)
else:
# reorder the categories (so rank can use the float codes)
# instead of passing an object array to rank
values = np.array(
self.rename_categories(Series(self.categories).rank().values)
)
return values
def view(self, dtype=None):
if dtype is not None:
raise NotImplementedError(dtype)
return self._constructor(values=self._codes, dtype=self.dtype, fastpath=True)
def to_dense(self):
"""
Return my 'dense' representation
For internal compatibility with numpy arrays.
Returns
-------
dense : array
"""
return np.asarray(self)
def fillna(self, value=None, method=None, limit=None):
"""
Fill NA/NaN values using the specified method.
Parameters
----------
value : scalar, dict, Series
If a scalar value is passed it is used to fill all missing values.
Alternatively, a Series or dict can be used to fill in different
values for each index. The value should not be a list. The
value(s) passed should either be in the categories or should be
NaN.
method : {'backfill', 'bfill', 'pad', 'ffill', None}, default None
Method to use for filling holes in reindexed Series
pad / ffill: propagate last valid observation forward to next valid
backfill / bfill: use NEXT valid observation to fill gap
limit : int, default None
(Not implemented yet for Categorical!)
If method is specified, this is the maximum number of consecutive
NaN values to forward/backward fill. In other words, if there is
a gap with more than this number of consecutive NaNs, it will only
be partially filled. If method is not specified, this is the
maximum number of entries along the entire axis where NaNs will be
filled.
Returns
-------
filled : Categorical with NA/NaN filled
"""
value, method = validate_fillna_kwargs(
value, method, validate_scalar_dict_value=False
)
if value is None:
value = np.nan
if limit is not None:
raise NotImplementedError(
"specifying a limit for fillna has not been implemented yet"
)
codes = self._codes
# pad / bfill
if method is not None:
values = self.to_dense().reshape(-1, len(self))
values = interpolate_2d(values, method, 0, None, value).astype(
self.categories.dtype
)[0]
codes = _get_codes_for_values(values, self.categories)
else:
# If value is a dict or a Series (a dict value has already
# been converted to a Series)
if isinstance(value, ABCSeries):
if not value[~value.isin(self.categories)].isna().all():
raise ValueError("fill value must be in categories")
values_codes = _get_codes_for_values(value, self.categories)
indexer = np.where(codes == -1)
codes[indexer] = values_codes[indexer]
# If value is not a dict or Series it should be a scalar
elif is_hashable(value):
if not isna(value) and value not in self.categories:
raise ValueError("fill value must be in categories")
mask = codes == -1
if mask.any():
codes = codes.copy()
if isna(value):
codes[mask] = -1
else:
codes[mask] = self.categories.get_loc(value)
else:
raise TypeError(
f"'value' parameter must be a scalar, dict "
f"or Series, but you passed a {type(value).__name__}"
)
return self._constructor(codes, dtype=self.dtype, fastpath=True)
def take(self, indexer, allow_fill: bool = False, fill_value=None):
"""
Take elements from the Categorical.
Parameters
----------
indexer : sequence of int
The indices in `self` to take. The meaning of negative values in
`indexer` depends on the value of `allow_fill`.
allow_fill : bool, default False
How to handle negative values in `indexer`.
* False: negative values in `indices` indicate positional indices
from the right. This is similar to
:func:`numpy.take`.
* True: negative values in `indices` indicate missing values
(the default). These values are set to `fill_value`. Any other
other negative values raise a ``ValueError``.
.. versionchanged:: 1.0.0
Default value changed from ``True`` to ``False``.
fill_value : object
The value to use for `indices` that are missing (-1), when
``allow_fill=True``. This should be the category, i.e. a value
in ``self.categories``, not a code.
Returns
-------
Categorical
This Categorical will have the same categories and ordered as
`self`.
See Also
--------
Series.take : Similar method for Series.
numpy.ndarray.take : Similar method for NumPy arrays.
Examples
--------
>>> cat = pd.Categorical(['a', 'a', 'b'])
>>> cat
[a, a, b]
Categories (2, object): [a, b]
Specify ``allow_fill==False`` to have negative indices mean indexing
from the right.
>>> cat.take([0, -1, -2], allow_fill=False)
[a, b, a]
Categories (2, object): [a, b]
With ``allow_fill=True``, indices equal to ``-1`` mean "missing"
values that should be filled with the `fill_value`, which is
``np.nan`` by default.
>>> cat.take([0, -1, -1], allow_fill=True)
[a, NaN, NaN]
Categories (2, object): [a, b]
The fill value can be specified.
>>> cat.take([0, -1, -1], allow_fill=True, fill_value='a')
[a, a, a]
Categories (3, object): [a, b]
Specifying a fill value that's not in ``self.categories``
will raise a ``TypeError``.
"""
indexer = np.asarray(indexer, dtype=np.intp)
dtype = self.dtype
if isna(fill_value):
fill_value = -1
elif allow_fill:
# convert user-provided `fill_value` to codes
if fill_value in self.categories:
fill_value = self.categories.get_loc(fill_value)
else:
msg = (
f"'fill_value' ('{fill_value}') is not in this "
"Categorical's categories."
)
raise TypeError(msg)
codes = take(self._codes, indexer, allow_fill=allow_fill, fill_value=fill_value)
result = type(self).from_codes(codes, dtype=dtype)
return result
def take_nd(self, indexer, allow_fill: bool = False, fill_value=None):
# GH#27745 deprecate alias that other EAs dont have
warn(
"Categorical.take_nd is deprecated, use Categorical.take instead",
FutureWarning,
stacklevel=2,
)
return self.take(indexer, allow_fill=allow_fill, fill_value=fill_value)
def __len__(self) -> int:
"""
The length of this Categorical.
"""
return len(self._codes)
def __iter__(self):
"""
Returns an Iterator over the values of this Categorical.
"""
return iter(self._internal_get_values().tolist())
def __contains__(self, key) -> bool:
"""
Returns True if `key` is in this Categorical.
"""
# if key is a NaN, check if any NaN is in self.
if is_scalar(key) and isna(key):
return self.isna().any()
return contains(self, key, container=self._codes)
def _tidy_repr(self, max_vals=10, footer=True) -> str:
"""
a short repr displaying only max_vals and an optional (but default
footer)
"""
num = max_vals // 2
head = self[:num]._get_repr(length=False, footer=False)
tail = self[-(max_vals - num) :]._get_repr(length=False, footer=False)
result = f"{head[:-1]}, ..., {tail[1:]}"
if footer:
result = f"{result}\n{self._repr_footer()}"
return str(result)
def _repr_categories(self):
"""
return the base repr for the categories
"""
max_categories = (
10
if get_option("display.max_categories") == 0
else get_option("display.max_categories")
)
from pandas.io.formats import format as fmt
if len(self.categories) > max_categories:
num = max_categories // 2
head = fmt.format_array(self.categories[:num], None)
tail = fmt.format_array(self.categories[-num:], None)
category_strs = head + ["..."] + tail
else:
category_strs = fmt.format_array(self.categories, None)
# Strip all leading spaces, which format_array adds for columns...
category_strs = [x.strip() for x in category_strs]
return category_strs
def _repr_categories_info(self) -> str:
"""
Returns a string representation of the footer.
"""
category_strs = self._repr_categories()
dtype = str(self.categories.dtype)
levheader = f"Categories ({len(self.categories)}, {dtype}): "
width, height = get_terminal_size()
max_width = get_option("display.width") or width
if console.in_ipython_frontend():
# 0 = no breaks
max_width = 0
levstring = ""
start = True
cur_col_len = len(levheader) # header
sep_len, sep = (3, " < ") if self.ordered else (2, ", ")
linesep = sep.rstrip() + "\n" # remove whitespace
for val in category_strs:
if max_width != 0 and cur_col_len + sep_len + len(val) > max_width:
levstring += linesep + (" " * (len(levheader) + 1))
cur_col_len = len(levheader) + 1 # header + a whitespace
elif not start:
levstring += sep
cur_col_len += len(val)
levstring += val
start = False
# replace to simple save space by
return levheader + "[" + levstring.replace(" < ... < ", " ... ") + "]"
def _repr_footer(self) -> str:
info = self._repr_categories_info()
return f"Length: {len(self)}\n{info}"
def _get_repr(self, length=True, na_rep="NaN", footer=True) -> str:
from pandas.io.formats import format as fmt
formatter = fmt.CategoricalFormatter(
self, length=length, na_rep=na_rep, footer=footer
)
result = formatter.to_string()
return str(result)
def __repr__(self) -> str:
"""
String representation.
"""
_maxlen = 10
if len(self._codes) > _maxlen:
result = self._tidy_repr(_maxlen)
elif len(self._codes) > 0:
result = self._get_repr(length=len(self) > _maxlen)
else:
msg = self._get_repr(length=False, footer=True).replace("\n", ", ")
result = f"[], {msg}"
return result
def _maybe_coerce_indexer(self, indexer):
"""
return an indexer coerced to the codes dtype
"""
if isinstance(indexer, np.ndarray) and indexer.dtype.kind == "i":
indexer = indexer.astype(self._codes.dtype)
return indexer
def __getitem__(self, key):
"""
Return an item.
"""
if isinstance(key, (int, np.integer)):
i = self._codes[key]
if i == -1:
return np.nan
else:
return self.categories[i]
key = check_array_indexer(self, key)
result = self._codes[key]
if result.ndim > 1:
deprecate_ndim_indexing(result)
return result
return self._constructor(result, dtype=self.dtype, fastpath=True)
def __setitem__(self, key, value):
"""
Item assignment.
Raises
------
ValueError
If (one or more) Value is not in categories or if a assigned
`Categorical` does not have the same categories
"""
value = extract_array(value, extract_numpy=True)
# require identical categories set
if isinstance(value, Categorical):
if not is_dtype_equal(self, value):
raise ValueError(
"Cannot set a Categorical with another, "
"without identical categories"
)
if not self.categories.equals(value.categories):
new_codes = _recode_for_categories(
value.codes, value.categories, self.categories
)
value = Categorical.from_codes(new_codes, dtype=self.dtype)
rvalue = value if is_list_like(value) else [value]
from pandas import Index
to_add = Index(rvalue).difference(self.categories)
# no assignments of values not in categories, but it's always ok to set
# something to np.nan
if len(to_add) and not isna(to_add).all():
raise ValueError(
"Cannot setitem on a Categorical with a new "
"category, set the categories first"
)
# set by position
if isinstance(key, (int, np.integer)):
pass
# tuple of indexers (dataframe)
elif isinstance(key, tuple):
# only allow 1 dimensional slicing, but can
# in a 2-d case be passd (slice(None),....)
if len(key) == 2:
if not com.is_null_slice(key[0]):
raise AssertionError("invalid slicing for a 1-ndim categorical")
key = key[1]
elif len(key) == 1:
key = key[0]
else:
raise AssertionError("invalid slicing for a 1-ndim categorical")
# slicing in Series or Categorical
elif isinstance(key, slice):
pass
# else: array of True/False in Series or Categorical
lindexer = self.categories.get_indexer(rvalue)
lindexer = self._maybe_coerce_indexer(lindexer)
key = check_array_indexer(self, key)
self._codes[key] = lindexer
def _reverse_indexer(self) -> Dict[Hashable, np.ndarray]:
"""
Compute the inverse of a categorical, returning
a dict of categories -> indexers.
*This is an internal function*
Returns
-------
dict of categories -> indexers
Examples
--------
>>> c = pd.Categorical(list('aabca'))
>>> c
[a, a, b, c, a]
Categories (3, object): [a, b, c]
>>> c.categories
Index(['a', 'b', 'c'], dtype='object')
>>> c.codes
array([0, 0, 1, 2, 0], dtype=int8)
>>> c._reverse_indexer()
{'a': array([0, 1, 4]), 'b': array([2]), 'c': array([3])}
"""
categories = self.categories
r, counts = libalgos.groupsort_indexer(
self.codes.astype("int64"), categories.size
)
counts = counts.cumsum()
_result = (r[start:end] for start, end in zip(counts, counts[1:]))
result = dict(zip(categories, _result))
return result
# reduction ops #
def _reduce(self, name, axis=0, **kwargs):
func = getattr(self, name, None)
if func is None:
raise TypeError(f"Categorical cannot perform the operation {name}")
return func(**kwargs)
@deprecate_kwarg(old_arg_name="numeric_only", new_arg_name="skipna")
def min(self, skipna=True):
"""
The minimum value of the object.
Only ordered `Categoricals` have a minimum!
.. versionchanged:: 1.0.0
Returns an NA value on empty arrays
Raises
------
TypeError
If the `Categorical` is not `ordered`.
Returns
-------
min : the minimum of this `Categorical`
"""
self.check_for_ordered("min")
if not len(self._codes):
return self.dtype.na_value
good = self._codes != -1
if not good.all():
if skipna:
pointer = self._codes[good].min()
else:
return np.nan
else:
pointer = self._codes.min()
return self.categories[pointer]
@deprecate_kwarg(old_arg_name="numeric_only", new_arg_name="skipna")
def max(self, skipna=True):
"""
The maximum value of the object.
Only ordered `Categoricals` have a maximum!
.. versionchanged:: 1.0.0
Returns an NA value on empty arrays
Raises
------
TypeError
If the `Categorical` is not `ordered`.
Returns
-------
max : the maximum of this `Categorical`
"""
self.check_for_ordered("max")
if not len(self._codes):
return self.dtype.na_value
good = self._codes != -1
if not good.all():
if skipna:
pointer = self._codes[good].max()
else:
return np.nan
else:
pointer = self._codes.max()
return self.categories[pointer]
def mode(self, dropna=True):
"""
Returns the mode(s) of the Categorical.
Always returns `Categorical` even if only one value.
Parameters
----------
dropna : bool, default True
Don't consider counts of NaN/NaT.
.. versionadded:: 0.24.0
Returns
-------
modes : `Categorical` (sorted)
"""
codes = self._codes
if dropna:
good = self._codes != -1
codes = self._codes[good]
codes = sorted(htable.mode_int64(ensure_int64(codes), dropna))
return self._constructor(values=codes, dtype=self.dtype, fastpath=True)
def unique(self):
"""
Return the ``Categorical`` which ``categories`` and ``codes`` are
unique. Unused categories are NOT returned.
- unordered category: values and categories are sorted by appearance
order.
- ordered category: values are sorted by appearance order, categories
keeps existing order.
Returns
-------
unique values : ``Categorical``
Examples
--------
An unordered Categorical will return categories in the
order of appearance.
>>> pd.Categorical(list('baabc'))
[b, a, c]
Categories (3, object): [b, a, c]
>>> pd.Categorical(list('baabc'), categories=list('abc'))
[b, a, c]
Categories (3, object): [b, a, c]
An ordered Categorical preserves the category ordering.
>>> pd.Categorical(list('baabc'),
... categories=list('abc'),
... ordered=True)
[b, a, c]
Categories (3, object): [a < b < c]
See Also
--------
unique
CategoricalIndex.unique
Series.unique
"""
# unlike np.unique, unique1d does not sort
unique_codes = unique1d(self.codes)
cat = self.copy()
# keep nan in codes
cat._codes = unique_codes
# exclude nan from indexer for categories
take_codes = unique_codes[unique_codes != -1]
if self.ordered:
take_codes = np.sort(take_codes)
return cat.set_categories(cat.categories.take(take_codes))
def _values_for_factorize(self):
codes = self.codes.astype("int64")
return codes, -1
@classmethod
def _from_factorized(cls, uniques, original):
return original._constructor(
original.categories.take(uniques), dtype=original.dtype
)
def equals(self, other):
"""
Returns True if categorical arrays are equal.
Parameters
----------
other : `Categorical`
Returns
-------
bool
"""
if self.is_dtype_equal(other):
if self.categories.equals(other.categories):
# fastpath to avoid re-coding
other_codes = other._codes
else:
other_codes = _recode_for_categories(
other.codes, other.categories, self.categories
)
return np.array_equal(self._codes, other_codes)
return False
def is_dtype_equal(self, other):
"""
Returns True if categoricals are the same dtype
same categories, and same ordered
Parameters
----------
other : Categorical
Returns
-------
bool
"""
try:
return hash(self.dtype) == hash(other.dtype)
except (AttributeError, TypeError):
return False
def describe(self):
"""
Describes this Categorical
Returns
-------
description: `DataFrame`
A dataframe with frequency and counts by category.
"""
counts = self.value_counts(dropna=False)
freqs = counts / float(counts.sum())
from pandas.core.reshape.concat import concat
result = concat([counts, freqs], axis=1)
result.columns = ["counts", "freqs"]
result.index.name = "categories"
return result
@Substitution(klass="Categorical")
@Appender(_extension_array_shared_docs["repeat"])
def repeat(self, repeats, axis=None):
nv.validate_repeat(tuple(), dict(axis=axis))
codes = self._codes.repeat(repeats)
return self._constructor(values=codes, dtype=self.dtype, fastpath=True)
# Implement the ExtensionArray interface
@property
def _can_hold_na(self):
return True
@classmethod
def _concat_same_type(self, to_concat):
from pandas.core.dtypes.concat import concat_categorical
return concat_categorical(to_concat)
def isin(self, values):
"""
Check whether `values` are contained in Categorical.
Return a boolean NumPy Array showing whether each element in
the Categorical matches an element in the passed sequence of
`values` exactly.
Parameters
----------
values : set or list-like
The sequence of values to test. Passing in a single string will
raise a ``TypeError``. Instead, turn a single string into a
list of one element.
Returns
-------
isin : numpy.ndarray (bool dtype)
Raises
------
TypeError
* If `values` is not a set or list-like
See Also
--------
pandas.Series.isin : Equivalent method on Series.
Examples
--------
>>> s = pd.Categorical(['lama', 'cow', 'lama', 'beetle', 'lama',
... 'hippo'])
>>> s.isin(['cow', 'lama'])
array([ True, True, True, False, True, False])
Passing a single string as ``s.isin('lama')`` will raise an error. Use
a list of one element instead:
>>> s.isin(['lama'])
array([ True, False, True, False, True, False])
"""
if not is_list_like(values):
values_type = type(values).__name__
raise TypeError(
"only list-like objects are allowed to be passed "
f"to isin(), you passed a [{values_type}]"
)
values = sanitize_array(values, None, None)
null_mask = np.asarray(isna(values))
code_values = self.categories.get_indexer(values)
code_values = code_values[null_mask | (code_values >= 0)]
return algorithms.isin(self.codes, code_values)
def replace(self, to_replace, value, inplace: bool = False):
"""
Replaces all instances of one value with another
Parameters
----------
to_replace: object
The value to be replaced
value: object
The value to replace it with
inplace: bool
Whether the operation is done in-place
Returns
-------
None if inplace is True, otherwise the new Categorical after replacement
Examples
--------
>>> s = pd.Categorical([1, 2, 1, 3])
>>> s.replace(1, 3)
[3, 3, 2, 3]
Categories (2, int64): [2, 3]
"""
inplace = validate_bool_kwarg(inplace, "inplace")
cat = self if inplace else self.copy()
# build a dict of (to replace -> value) pairs
if is_list_like(to_replace):
# if to_replace is list-like and value is scalar
replace_dict = {replace_value: value for replace_value in to_replace}
else:
# if both to_replace and value are scalar
replace_dict = {to_replace: value}
# other cases, like if both to_replace and value are list-like or if
# to_replace is a dict, are handled separately in NDFrame
for replace_value, new_value in replace_dict.items():
if replace_value in cat.categories:
if isna(new_value):
cat.remove_categories(replace_value, inplace=True)
continue
categories = cat.categories.tolist()
index = categories.index(replace_value)
if new_value in cat.categories:
value_index = categories.index(new_value)
cat._codes[cat._codes == index] = value_index
cat.remove_categories(replace_value, inplace=True)
else:
categories[index] = new_value
cat.rename_categories(categories, inplace=True)
if not inplace:
return cat
# The Series.cat accessor
@delegate_names(
delegate=Categorical, accessors=["categories", "ordered"], typ="property"
)
@delegate_names(
delegate=Categorical,
accessors=[
"rename_categories",
"reorder_categories",
"add_categories",
"remove_categories",
"remove_unused_categories",
"set_categories",
"as_ordered",
"as_unordered",
],
typ="method",
)
class CategoricalAccessor(PandasDelegate, PandasObject, NoNewAttributesMixin):
"""
Accessor object for categorical properties of the Series values.
Be aware that assigning to `categories` is a inplace operation, while all
methods return new categorical data per default (but can be called with
`inplace=True`).
Parameters
----------
data : Series or CategoricalIndex
Examples
--------
>>> s.cat.categories
>>> s.cat.categories = list('abc')
>>> s.cat.rename_categories(list('cab'))
>>> s.cat.reorder_categories(list('cab'))
>>> s.cat.add_categories(['d','e'])
>>> s.cat.remove_categories(['d'])
>>> s.cat.remove_unused_categories()
>>> s.cat.set_categories(list('abcde'))
>>> s.cat.as_ordered()
>>> s.cat.as_unordered()
"""
def __init__(self, data):
self._validate(data)
self._parent = data.values
self._index = data.index
self._name = data.name
self._freeze()
@staticmethod
def _validate(data):
if not is_categorical_dtype(data.dtype):
raise AttributeError("Can only use .cat accessor with a 'category' dtype")
def _delegate_property_get(self, name):
return getattr(self._parent, name)
def _delegate_property_set(self, name, new_values):
return setattr(self._parent, name, new_values)
@property
def codes(self):
"""
Return Series of codes as well as the index.
"""
from pandas import Series
return Series(self._parent.codes, index=self._index)
def _delegate_method(self, name, *args, **kwargs):
from pandas import Series
method = getattr(self._parent, name)
res = method(*args, **kwargs)
if res is not None:
return Series(res, index=self._index, name=self._name)
# utility routines
def _get_codes_for_values(values, categories):
"""
utility routine to turn values into codes given the specified categories
"""
dtype_equal = is_dtype_equal(values.dtype, categories.dtype)
if dtype_equal:
# To prevent erroneous dtype coercion in _get_data_algo, retrieve
# the underlying numpy array. gh-22702
values = getattr(values, "_ndarray_values", values)
categories = getattr(categories, "_ndarray_values", categories)
elif is_extension_array_dtype(categories.dtype) and is_object_dtype(values):
# Support inferring the correct extension dtype from an array of
# scalar objects. e.g.
# Categorical(array[Period, Period], categories=PeriodIndex(...))
cls = categories.dtype.construct_array_type()
values = try_cast_to_ea(cls, values)
if not isinstance(values, cls):
# exception raised in _from_sequence
values = ensure_object(values)
categories = ensure_object(categories)
else:
values = ensure_object(values)
categories = ensure_object(categories)
hash_klass, vals = _get_data_algo(values)
_, cats = _get_data_algo(categories)
t = hash_klass(len(cats))
t.map_locations(cats)
return coerce_indexer_dtype(t.lookup(vals), cats)
def _recode_for_categories(codes: np.ndarray, old_categories, new_categories):
"""
Convert a set of codes for to a new set of categories
Parameters
----------
codes : np.ndarray
old_categories, new_categories : Index
Returns
-------
new_codes : np.ndarray[np.int64]
Examples
--------
>>> old_cat = pd.Index(['b', 'a', 'c'])
>>> new_cat = pd.Index(['a', 'b'])
>>> codes = np.array([0, 1, 1, 2])
>>> _recode_for_categories(codes, old_cat, new_cat)
array([ 1, 0, 0, -1])
"""
if len(old_categories) == 0:
# All null anyway, so just retain the nulls
return codes.copy()
elif new_categories.equals(old_categories):
# Same categories, so no need to actually recode
return codes.copy()
indexer = coerce_indexer_dtype(
new_categories.get_indexer(old_categories), new_categories
)
new_codes = take_1d(indexer, codes.copy(), fill_value=-1)
return new_codes
def _convert_to_list_like(list_like):
if hasattr(list_like, "dtype"):
return list_like
if isinstance(list_like, list):
return list_like
if is_sequence(list_like) or isinstance(list_like, tuple) or is_iterator(list_like):
return list(list_like)
elif is_scalar(list_like):
return [list_like]
else:
# TODO: is this reached?
return [list_like]
def factorize_from_iterable(values):
"""
Factorize an input `values` into `categories` and `codes`. Preserves
categorical dtype in `categories`.
*This is an internal function*
Parameters
----------
values : list-like
Returns
-------
codes : ndarray
categories : Index
If `values` has a categorical dtype, then `categories` is
a CategoricalIndex keeping the categories and order of `values`.
"""
if not is_list_like(values):
raise TypeError("Input must be list-like")
if is_categorical_dtype(values):
values = extract_array(values)
# The Categorical we want to build has the same categories
# as values but its codes are by def [0, ..., len(n_categories) - 1]
cat_codes = np.arange(len(values.categories), dtype=values.codes.dtype)
categories = Categorical.from_codes(cat_codes, dtype=values.dtype)
codes = values.codes
else:
# The value of ordered is irrelevant since we don't use cat as such,
# but only the resulting categories, the order of which is independent
# from ordered. Set ordered to False as default. See GH #15457
cat = Categorical(values, ordered=False)
categories = cat.categories
codes = cat.codes
return codes, categories
def factorize_from_iterables(iterables):
"""
A higher-level wrapper over `factorize_from_iterable`.
*This is an internal function*
Parameters
----------
iterables : list-like of list-likes
Returns
-------
codes_list : list of ndarrays
categories_list : list of Indexes
Notes
-----
See `factorize_from_iterable` for more info.
"""
if len(iterables) == 0:
# For consistency, it should return a list of 2 lists.
return [[], []]
return map(list, zip(*(factorize_from_iterable(it) for it in iterables)))
| BugsInPy/BugsInPy/temp/projects/pandas/bug-50-fixed/pandas/pandas/core/arrays/categorical.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-50-buggy/pandas/pandas/core/arrays/categorical.py |
pandas-bug-119 | from typing import TYPE_CHECKING, Callable, Dict, Tuple, Union
import numpy as np
from pandas.util._decorators import Appender, Substitution
from pandas.core.dtypes.cast import maybe_downcast_to_dtype
from pandas.core.dtypes.common import is_integer_dtype, is_list_like, is_scalar
from pandas.core.dtypes.generic import ABCDataFrame, ABCSeries
import pandas.core.common as com
from pandas.core.frame import _shared_docs
from pandas.core.groupby import Grouper
from pandas.core.index import Index, MultiIndex, get_objs_combined_axis
from pandas.core.reshape.concat import concat
from pandas.core.reshape.util import cartesian_product
from pandas.core.series import Series
if TYPE_CHECKING:
from pandas import DataFrame
# Note: We need to make sure `frame` is imported before `pivot`, otherwise
# _shared_docs['pivot_table'] will not yet exist. TODO: Fix this dependency
@Substitution("\ndata : DataFrame")
@Appender(_shared_docs["pivot_table"], indents=1)
def pivot_table(
data,
values=None,
index=None,
columns=None,
aggfunc="mean",
fill_value=None,
margins=False,
dropna=True,
margins_name="All",
observed=False,
):
index = _convert_by(index)
columns = _convert_by(columns)
if isinstance(aggfunc, list):
pieces = []
keys = []
for func in aggfunc:
table = pivot_table(
data,
values=values,
index=index,
columns=columns,
fill_value=fill_value,
aggfunc=func,
margins=margins,
dropna=dropna,
margins_name=margins_name,
observed=observed,
)
pieces.append(table)
keys.append(getattr(func, "__name__", func))
return concat(pieces, keys=keys, axis=1)
keys = index + columns
values_passed = values is not None
if values_passed:
if is_list_like(values):
values_multi = True
values = list(values)
else:
values_multi = False
values = [values]
# GH14938 Make sure value labels are in data
for i in values:
if i not in data:
raise KeyError(i)
to_filter = []
for x in keys + values:
if isinstance(x, Grouper):
x = x.key
try:
if x in data:
to_filter.append(x)
except TypeError:
pass
if len(to_filter) < len(data.columns):
data = data[to_filter]
else:
values = data.columns
for key in keys:
try:
values = values.drop(key)
except (TypeError, ValueError, KeyError):
pass
values = list(values)
grouped = data.groupby(keys, observed=observed)
agged = grouped.agg(aggfunc)
if dropna and isinstance(agged, ABCDataFrame) and len(agged.columns):
agged = agged.dropna(how="all")
# gh-21133
# we want to down cast if
# the original values are ints
# as we grouped with a NaN value
# and then dropped, coercing to floats
for v in values:
if (
v in data
and is_integer_dtype(data[v])
and v in agged
and not is_integer_dtype(agged[v])
):
agged[v] = maybe_downcast_to_dtype(agged[v], data[v].dtype)
table = agged
if table.index.nlevels > 1:
# Related GH #17123
# If index_names are integers, determine whether the integers refer
# to the level position or name.
index_names = agged.index.names[: len(index)]
to_unstack = []
for i in range(len(index), len(keys)):
name = agged.index.names[i]
if name is None or name in index_names:
to_unstack.append(i)
else:
to_unstack.append(name)
table = agged.unstack(to_unstack)
if not dropna:
if table.index.nlevels > 1:
m = MultiIndex.from_arrays(
cartesian_product(table.index.levels), names=table.index.names
)
table = table.reindex(m, axis=0)
if table.columns.nlevels > 1:
m = MultiIndex.from_arrays(
cartesian_product(table.columns.levels), names=table.columns.names
)
table = table.reindex(m, axis=1)
if isinstance(table, ABCDataFrame):
table = table.sort_index(axis=1)
if fill_value is not None:
table = table.fillna(value=fill_value, downcast="infer")
if margins:
if dropna:
data = data[data.notna().all(axis=1)]
table = _add_margins(
table,
data,
values,
rows=index,
cols=columns,
aggfunc=aggfunc,
observed=dropna,
margins_name=margins_name,
fill_value=fill_value,
)
# discard the top level
if (
values_passed
and not values_multi
and not table.empty
and (table.columns.nlevels > 1)
):
table = table[values[0]]
if len(index) == 0 and len(columns) > 0:
table = table.T
# GH 15193 Make sure empty columns are removed if dropna=True
if isinstance(table, ABCDataFrame) and dropna:
table = table.dropna(how="all", axis=1)
return table
def _add_margins(
table: Union["Series", "DataFrame"],
data,
values,
rows,
cols,
aggfunc,
observed=None,
margins_name: str = "All",
fill_value=None,
):
if not isinstance(margins_name, str):
raise ValueError("margins_name argument must be a string")
msg = 'Conflicting name "{name}" in margins'.format(name=margins_name)
for level in table.index.names:
if margins_name in table.index.get_level_values(level):
raise ValueError(msg)
grand_margin = _compute_grand_margin(data, values, aggfunc, margins_name)
if table.ndim == 2:
# i.e. DataFramae
for level in table.columns.names[1:]:
if margins_name in table.columns.get_level_values(level):
raise ValueError(msg)
key: Union[str, Tuple[str, ...]]
if len(rows) > 1:
key = (margins_name,) + ("",) * (len(rows) - 1)
else:
key = margins_name
if not values and isinstance(table, ABCSeries):
# If there are no values and the table is a series, then there is only
# one column in the data. Compute grand margin and return it.
return table.append(Series({key: grand_margin[margins_name]}))
elif values:
marginal_result_set = _generate_marginal_results(
table,
data,
values,
rows,
cols,
aggfunc,
observed,
grand_margin,
margins_name,
)
if not isinstance(marginal_result_set, tuple):
return marginal_result_set
result, margin_keys, row_margin = marginal_result_set
else:
# no values, and table is a DataFrame
assert isinstance(table, ABCDataFrame)
marginal_result_set = _generate_marginal_results_without_values(
table, data, rows, cols, aggfunc, observed, margins_name
)
if not isinstance(marginal_result_set, tuple):
return marginal_result_set
result, margin_keys, row_margin = marginal_result_set
row_margin = row_margin.reindex(result.columns, fill_value=fill_value)
# populate grand margin
for k in margin_keys:
if isinstance(k, str):
row_margin[k] = grand_margin[k]
else:
row_margin[k] = grand_margin[k[0]]
from pandas import DataFrame
margin_dummy = DataFrame(row_margin, columns=[key]).T
row_names = result.index.names
try:
for dtype in set(result.dtypes):
cols = result.select_dtypes([dtype]).columns
margin_dummy[cols] = margin_dummy[cols].astype(dtype)
result = result.append(margin_dummy)
except TypeError:
# we cannot reshape, so coerce the axis
result.index = result.index._to_safe_for_reshape()
result = result.append(margin_dummy)
result.index.names = row_names
return result
def _compute_grand_margin(data, values, aggfunc, margins_name: str = "All"):
if values:
grand_margin = {}
for k, v in data[values].items():
try:
if isinstance(aggfunc, str):
grand_margin[k] = getattr(v, aggfunc)()
elif isinstance(aggfunc, dict):
if isinstance(aggfunc[k], str):
grand_margin[k] = getattr(v, aggfunc[k])()
else:
grand_margin[k] = aggfunc[k](v)
else:
grand_margin[k] = aggfunc(v)
except TypeError:
pass
return grand_margin
else:
return {margins_name: aggfunc(data.index)}
def _generate_marginal_results(
table,
data,
values,
rows,
cols,
aggfunc,
observed,
grand_margin,
margins_name: str = "All",
):
if len(cols) > 0:
# need to "interleave" the margins
table_pieces = []
margin_keys = []
def _all_key(key):
return (key, margins_name) + ("",) * (len(cols) - 1)
if len(rows) > 0:
margin = data[rows + values].groupby(rows, observed=observed).agg(aggfunc)
cat_axis = 1
for key, piece in table.groupby(level=0, axis=cat_axis, observed=observed):
all_key = _all_key(key)
# we are going to mutate this, so need to copy!
piece = piece.copy()
try:
piece[all_key] = margin[key]
except TypeError:
# we cannot reshape, so coerce the axis
piece.set_axis(
piece._get_axis(cat_axis)._to_safe_for_reshape(),
axis=cat_axis,
inplace=True,
)
piece[all_key] = margin[key]
table_pieces.append(piece)
margin_keys.append(all_key)
else:
margin = grand_margin
cat_axis = 0
for key, piece in table.groupby(level=0, axis=cat_axis, observed=observed):
all_key = _all_key(key)
table_pieces.append(piece)
table_pieces.append(Series(margin[key], index=[all_key]))
margin_keys.append(all_key)
result = concat(table_pieces, axis=cat_axis)
if len(rows) == 0:
return result
else:
result = table
margin_keys = table.columns
if len(cols) > 0:
row_margin = data[cols + values].groupby(cols, observed=observed).agg(aggfunc)
row_margin = row_margin.stack()
# slight hack
new_order = [len(cols)] + list(range(len(cols)))
row_margin.index = row_margin.index.reorder_levels(new_order)
else:
row_margin = Series(np.nan, index=result.columns)
return result, margin_keys, row_margin
def _generate_marginal_results_without_values(
table: "DataFrame", data, rows, cols, aggfunc, observed, margins_name: str = "All"
):
if len(cols) > 0:
# need to "interleave" the margins
margin_keys = []
def _all_key():
if len(cols) == 1:
return margins_name
return (margins_name,) + ("",) * (len(cols) - 1)
if len(rows) > 0:
margin = data[rows].groupby(rows, observed=observed).apply(aggfunc)
all_key = _all_key()
table[all_key] = margin
result = table
margin_keys.append(all_key)
else:
margin = data.groupby(level=0, axis=0, observed=observed).apply(aggfunc)
all_key = _all_key()
table[all_key] = margin
result = table
margin_keys.append(all_key)
return result
else:
result = table
margin_keys = table.columns
if len(cols):
row_margin = data[cols].groupby(cols, observed=observed).apply(aggfunc)
else:
row_margin = Series(np.nan, index=result.columns)
return result, margin_keys, row_margin
def _convert_by(by):
if by is None:
by = []
elif (
is_scalar(by)
or isinstance(by, (np.ndarray, Index, ABCSeries, Grouper))
or hasattr(by, "__call__")
):
by = [by]
else:
by = list(by)
return by
@Substitution("\ndata : DataFrame")
@Appender(_shared_docs["pivot"], indents=1)
def pivot(data: "DataFrame", index=None, columns=None, values=None):
if values is None:
cols = [columns] if index is None else [index, columns]
append = index is None
indexed = data.set_index(cols, append=append)
else:
if index is None:
index = data.index
else:
index = data[index]
index = MultiIndex.from_arrays([index, data[columns]])
if is_list_like(values) and not isinstance(values, tuple):
# Exclude tuple because it is seen as a single column name
indexed = data._constructor(
data[values].values, index=index, columns=values
)
else:
indexed = data._constructor_sliced(data[values].values, index=index)
return indexed.unstack(columns)
def crosstab(
index,
columns,
values=None,
rownames=None,
colnames=None,
aggfunc=None,
margins=False,
margins_name: str = "All",
dropna: bool = True,
normalize=False,
):
"""
Compute a simple cross tabulation of two (or more) factors. By default
computes a frequency table of the factors unless an array of values and an
aggregation function are passed.
Parameters
----------
index : array-like, Series, or list of arrays/Series
Values to group by in the rows.
columns : array-like, Series, or list of arrays/Series
Values to group by in the columns.
values : array-like, optional
Array of values to aggregate according to the factors.
Requires `aggfunc` be specified.
rownames : sequence, default None
If passed, must match number of row arrays passed.
colnames : sequence, default None
If passed, must match number of column arrays passed.
aggfunc : function, optional
If specified, requires `values` be specified as well.
margins : bool, default False
Add row/column margins (subtotals).
margins_name : str, default 'All'
Name of the row/column that will contain the totals
when margins is True.
.. versionadded:: 0.21.0
dropna : bool, default True
Do not include columns whose entries are all NaN.
normalize : bool, {'all', 'index', 'columns'}, or {0,1}, default False
Normalize by dividing all values by the sum of values.
- If passed 'all' or `True`, will normalize over all values.
- If passed 'index' will normalize over each row.
- If passed 'columns' will normalize over each column.
- If margins is `True`, will also normalize margin values.
Returns
-------
DataFrame
Cross tabulation of the data.
See Also
--------
DataFrame.pivot : Reshape data based on column values.
pivot_table : Create a pivot table as a DataFrame.
Notes
-----
Any Series passed will have their name attributes used unless row or column
names for the cross-tabulation are specified.
Any input passed containing Categorical data will have **all** of its
categories included in the cross-tabulation, even if the actual data does
not contain any instances of a particular category.
In the event that there aren't overlapping indexes an empty DataFrame will
be returned.
Examples
--------
>>> a = np.array(["foo", "foo", "foo", "foo", "bar", "bar",
... "bar", "bar", "foo", "foo", "foo"], dtype=object)
>>> b = np.array(["one", "one", "one", "two", "one", "one",
... "one", "two", "two", "two", "one"], dtype=object)
>>> c = np.array(["dull", "dull", "shiny", "dull", "dull", "shiny",
... "shiny", "dull", "shiny", "shiny", "shiny"],
... dtype=object)
>>> pd.crosstab(a, [b, c], rownames=['a'], colnames=['b', 'c'])
b one two
c dull shiny dull shiny
a
bar 1 2 1 0
foo 2 2 1 2
Here 'c' and 'f' are not represented in the data and will not be
shown in the output because dropna is True by default. Set
dropna=False to preserve categories with no data.
>>> foo = pd.Categorical(['a', 'b'], categories=['a', 'b', 'c'])
>>> bar = pd.Categorical(['d', 'e'], categories=['d', 'e', 'f'])
>>> pd.crosstab(foo, bar)
col_0 d e
row_0
a 1 0
b 0 1
>>> pd.crosstab(foo, bar, dropna=False)
col_0 d e f
row_0
a 1 0 0
b 0 1 0
c 0 0 0
"""
index = com.maybe_make_list(index)
columns = com.maybe_make_list(columns)
rownames = _get_names(index, rownames, prefix="row")
colnames = _get_names(columns, colnames, prefix="col")
common_idx = None
pass_objs = [x for x in index + columns if isinstance(x, (ABCSeries, ABCDataFrame))]
if pass_objs:
common_idx = get_objs_combined_axis(pass_objs, intersect=True, sort=False)
data: Dict = {}
data.update(zip(rownames, index))
data.update(zip(colnames, columns))
if values is None and aggfunc is not None:
raise ValueError("aggfunc cannot be used without values.")
if values is not None and aggfunc is None:
raise ValueError("values cannot be used without an aggfunc.")
from pandas import DataFrame
df = DataFrame(data, index=common_idx)
if values is None:
df["__dummy__"] = 0
kwargs = {"aggfunc": len, "fill_value": 0}
else:
df["__dummy__"] = values
kwargs = {"aggfunc": aggfunc}
table = df.pivot_table(
"__dummy__",
index=rownames,
columns=colnames,
margins=margins,
margins_name=margins_name,
dropna=dropna,
**kwargs,
)
# Post-process
if normalize is not False:
table = _normalize(
table, normalize=normalize, margins=margins, margins_name=margins_name
)
return table
def _normalize(table, normalize, margins: bool, margins_name="All"):
if not isinstance(normalize, (bool, str)):
axis_subs = {0: "index", 1: "columns"}
try:
normalize = axis_subs[normalize]
except KeyError:
raise ValueError("Not a valid normalize argument")
if margins is False:
# Actual Normalizations
normalizers: Dict[Union[bool, str], Callable] = {
"all": lambda x: x / x.sum(axis=1).sum(axis=0),
"columns": lambda x: x / x.sum(),
"index": lambda x: x.div(x.sum(axis=1), axis=0),
}
normalizers[True] = normalizers["all"]
try:
f = normalizers[normalize]
except KeyError:
raise ValueError("Not a valid normalize argument")
table = f(table)
table = table.fillna(0)
elif margins is True:
# keep index and column of pivoted table
table_index = table.index
table_columns = table.columns
# check if margin name is in (for MI cases) or equal to last
# index/column and save the column and index margin
if (margins_name not in table.iloc[-1, :].name) | (
margins_name != table.iloc[:, -1].name
):
raise ValueError(
"{mname} not in pivoted DataFrame".format(mname=margins_name)
)
column_margin = table.iloc[:-1, -1]
index_margin = table.iloc[-1, :-1]
# keep the core table
table = table.iloc[:-1, :-1]
# Normalize core
table = _normalize(table, normalize=normalize, margins=False)
# Fix Margins
if normalize == "columns":
column_margin = column_margin / column_margin.sum()
table = concat([table, column_margin], axis=1)
table = table.fillna(0)
table.columns = table_columns
elif normalize == "index":
index_margin = index_margin / index_margin.sum()
table = table.append(index_margin)
table = table.fillna(0)
table.index = table_index
elif normalize == "all" or normalize is True:
column_margin = column_margin / column_margin.sum()
index_margin = index_margin / index_margin.sum()
index_margin.loc[margins_name] = 1
table = concat([table, column_margin], axis=1)
table = table.append(index_margin)
table = table.fillna(0)
table.index = table_index
table.columns = table_columns
else:
raise ValueError("Not a valid normalize argument")
else:
raise ValueError("Not a valid margins argument")
return table
def _get_names(arrs, names, prefix: str = "row"):
if names is None:
names = []
for i, arr in enumerate(arrs):
if isinstance(arr, ABCSeries) and arr.name is not None:
names.append(arr.name)
else:
names.append("{prefix}_{i}".format(prefix=prefix, i=i))
else:
if len(names) != len(arrs):
raise AssertionError("arrays and names must have the same length")
if not isinstance(names, list):
names = list(names)
return names
from typing import TYPE_CHECKING, Callable, Dict, Tuple, Union
import numpy as np
from pandas.util._decorators import Appender, Substitution
from pandas.core.dtypes.cast import maybe_downcast_to_dtype
from pandas.core.dtypes.common import is_integer_dtype, is_list_like, is_scalar
from pandas.core.dtypes.generic import ABCDataFrame, ABCSeries
import pandas.core.common as com
from pandas.core.frame import _shared_docs
from pandas.core.groupby import Grouper
from pandas.core.index import Index, MultiIndex, get_objs_combined_axis
from pandas.core.reshape.concat import concat
from pandas.core.reshape.util import cartesian_product
from pandas.core.series import Series
if TYPE_CHECKING:
from pandas import DataFrame
# Note: We need to make sure `frame` is imported before `pivot`, otherwise
# _shared_docs['pivot_table'] will not yet exist. TODO: Fix this dependency
@Substitution("\ndata : DataFrame")
@Appender(_shared_docs["pivot_table"], indents=1)
def pivot_table(
data,
values=None,
index=None,
columns=None,
aggfunc="mean",
fill_value=None,
margins=False,
dropna=True,
margins_name="All",
observed=False,
):
index = _convert_by(index)
columns = _convert_by(columns)
if isinstance(aggfunc, list):
pieces = []
keys = []
for func in aggfunc:
table = pivot_table(
data,
values=values,
index=index,
columns=columns,
fill_value=fill_value,
aggfunc=func,
margins=margins,
dropna=dropna,
margins_name=margins_name,
observed=observed,
)
pieces.append(table)
keys.append(getattr(func, "__name__", func))
return concat(pieces, keys=keys, axis=1)
keys = index + columns
values_passed = values is not None
if values_passed:
if is_list_like(values):
values_multi = True
values = list(values)
else:
values_multi = False
values = [values]
# GH14938 Make sure value labels are in data
for i in values:
if i not in data:
raise KeyError(i)
to_filter = []
for x in keys + values:
if isinstance(x, Grouper):
x = x.key
try:
if x in data:
to_filter.append(x)
except TypeError:
pass
if len(to_filter) < len(data.columns):
data = data[to_filter]
else:
values = data.columns
for key in keys:
try:
values = values.drop(key)
except (TypeError, ValueError, KeyError):
pass
values = list(values)
grouped = data.groupby(keys, observed=observed)
agged = grouped.agg(aggfunc)
if dropna and isinstance(agged, ABCDataFrame) and len(agged.columns):
agged = agged.dropna(how="all")
# gh-21133
# we want to down cast if
# the original values are ints
# as we grouped with a NaN value
# and then dropped, coercing to floats
for v in values:
if (
v in data
and is_integer_dtype(data[v])
and v in agged
and not is_integer_dtype(agged[v])
):
agged[v] = maybe_downcast_to_dtype(agged[v], data[v].dtype)
table = agged
if table.index.nlevels > 1:
# Related GH #17123
# If index_names are integers, determine whether the integers refer
# to the level position or name.
index_names = agged.index.names[: len(index)]
to_unstack = []
for i in range(len(index), len(keys)):
name = agged.index.names[i]
if name is None or name in index_names:
to_unstack.append(i)
else:
to_unstack.append(name)
table = agged.unstack(to_unstack)
if not dropna:
if table.index.nlevels > 1:
m = MultiIndex.from_arrays(
cartesian_product(table.index.levels), names=table.index.names
)
table = table.reindex(m, axis=0)
if table.columns.nlevels > 1:
m = MultiIndex.from_arrays(
cartesian_product(table.columns.levels), names=table.columns.names
)
table = table.reindex(m, axis=1)
if isinstance(table, ABCDataFrame):
table = table.sort_index(axis=1)
if fill_value is not None:
table = table.fillna(value=fill_value, downcast="infer")
if margins:
if dropna:
data = data[data.notna().all(axis=1)]
table = _add_margins(
table,
data,
values,
rows=index,
cols=columns,
aggfunc=aggfunc,
observed=dropna,
margins_name=margins_name,
fill_value=fill_value,
)
# discard the top level
if (
values_passed
and not values_multi
and not table.empty
and (table.columns.nlevels > 1)
):
table = table[values[0]]
if len(index) == 0 and len(columns) > 0:
table = table.T
# GH 15193 Make sure empty columns are removed if dropna=True
if isinstance(table, ABCDataFrame) and dropna:
table = table.dropna(how="all", axis=1)
return table
def _add_margins(
table: Union["Series", "DataFrame"],
data,
values,
rows,
cols,
aggfunc,
observed=None,
margins_name: str = "All",
fill_value=None,
):
if not isinstance(margins_name, str):
raise ValueError("margins_name argument must be a string")
msg = 'Conflicting name "{name}" in margins'.format(name=margins_name)
for level in table.index.names:
if margins_name in table.index.get_level_values(level):
raise ValueError(msg)
grand_margin = _compute_grand_margin(data, values, aggfunc, margins_name)
if table.ndim == 2:
# i.e. DataFramae
for level in table.columns.names[1:]:
if margins_name in table.columns.get_level_values(level):
raise ValueError(msg)
key: Union[str, Tuple[str, ...]]
if len(rows) > 1:
key = (margins_name,) + ("",) * (len(rows) - 1)
else:
key = margins_name
if not values and isinstance(table, ABCSeries):
# If there are no values and the table is a series, then there is only
# one column in the data. Compute grand margin and return it.
return table.append(Series({key: grand_margin[margins_name]}))
elif values:
marginal_result_set = _generate_marginal_results(
table,
data,
values,
rows,
cols,
aggfunc,
observed,
grand_margin,
margins_name,
)
if not isinstance(marginal_result_set, tuple):
return marginal_result_set
result, margin_keys, row_margin = marginal_result_set
else:
# no values, and table is a DataFrame
assert isinstance(table, ABCDataFrame)
marginal_result_set = _generate_marginal_results_without_values(
table, data, rows, cols, aggfunc, observed, margins_name
)
if not isinstance(marginal_result_set, tuple):
return marginal_result_set
result, margin_keys, row_margin = marginal_result_set
row_margin = row_margin.reindex(result.columns, fill_value=fill_value)
# populate grand margin
for k in margin_keys:
if isinstance(k, str):
row_margin[k] = grand_margin[k]
else:
row_margin[k] = grand_margin[k[0]]
from pandas import DataFrame
margin_dummy = DataFrame(row_margin, columns=[key]).T
row_names = result.index.names
try:
# check the result column and leave floats
for dtype in set(result.dtypes):
cols = result.select_dtypes([dtype]).columns
margin_dummy[cols] = margin_dummy[cols].apply(
maybe_downcast_to_dtype, args=(dtype,)
)
result = result.append(margin_dummy)
except TypeError:
# we cannot reshape, so coerce the axis
result.index = result.index._to_safe_for_reshape()
result = result.append(margin_dummy)
result.index.names = row_names
return result
def _compute_grand_margin(data, values, aggfunc, margins_name: str = "All"):
if values:
grand_margin = {}
for k, v in data[values].items():
try:
if isinstance(aggfunc, str):
grand_margin[k] = getattr(v, aggfunc)()
elif isinstance(aggfunc, dict):
if isinstance(aggfunc[k], str):
grand_margin[k] = getattr(v, aggfunc[k])()
else:
grand_margin[k] = aggfunc[k](v)
else:
grand_margin[k] = aggfunc(v)
except TypeError:
pass
return grand_margin
else:
return {margins_name: aggfunc(data.index)}
def _generate_marginal_results(
table,
data,
values,
rows,
cols,
aggfunc,
observed,
grand_margin,
margins_name: str = "All",
):
if len(cols) > 0:
# need to "interleave" the margins
table_pieces = []
margin_keys = []
def _all_key(key):
return (key, margins_name) + ("",) * (len(cols) - 1)
if len(rows) > 0:
margin = data[rows + values].groupby(rows, observed=observed).agg(aggfunc)
cat_axis = 1
for key, piece in table.groupby(level=0, axis=cat_axis, observed=observed):
all_key = _all_key(key)
# we are going to mutate this, so need to copy!
piece = piece.copy()
try:
piece[all_key] = margin[key]
except TypeError:
# we cannot reshape, so coerce the axis
piece.set_axis(
piece._get_axis(cat_axis)._to_safe_for_reshape(),
axis=cat_axis,
inplace=True,
)
piece[all_key] = margin[key]
table_pieces.append(piece)
margin_keys.append(all_key)
else:
margin = grand_margin
cat_axis = 0
for key, piece in table.groupby(level=0, axis=cat_axis, observed=observed):
all_key = _all_key(key)
table_pieces.append(piece)
table_pieces.append(Series(margin[key], index=[all_key]))
margin_keys.append(all_key)
result = concat(table_pieces, axis=cat_axis)
if len(rows) == 0:
return result
else:
result = table
margin_keys = table.columns
if len(cols) > 0:
row_margin = data[cols + values].groupby(cols, observed=observed).agg(aggfunc)
row_margin = row_margin.stack()
# slight hack
new_order = [len(cols)] + list(range(len(cols)))
row_margin.index = row_margin.index.reorder_levels(new_order)
else:
row_margin = Series(np.nan, index=result.columns)
return result, margin_keys, row_margin
def _generate_marginal_results_without_values(
table: "DataFrame", data, rows, cols, aggfunc, observed, margins_name: str = "All"
):
if len(cols) > 0:
# need to "interleave" the margins
margin_keys = []
def _all_key():
if len(cols) == 1:
return margins_name
return (margins_name,) + ("",) * (len(cols) - 1)
if len(rows) > 0:
margin = data[rows].groupby(rows, observed=observed).apply(aggfunc)
all_key = _all_key()
table[all_key] = margin
result = table
margin_keys.append(all_key)
else:
margin = data.groupby(level=0, axis=0, observed=observed).apply(aggfunc)
all_key = _all_key()
table[all_key] = margin
result = table
margin_keys.append(all_key)
return result
else:
result = table
margin_keys = table.columns
if len(cols):
row_margin = data[cols].groupby(cols, observed=observed).apply(aggfunc)
else:
row_margin = Series(np.nan, index=result.columns)
return result, margin_keys, row_margin
def _convert_by(by):
if by is None:
by = []
elif (
is_scalar(by)
or isinstance(by, (np.ndarray, Index, ABCSeries, Grouper))
or hasattr(by, "__call__")
):
by = [by]
else:
by = list(by)
return by
@Substitution("\ndata : DataFrame")
@Appender(_shared_docs["pivot"], indents=1)
def pivot(data: "DataFrame", index=None, columns=None, values=None):
if values is None:
cols = [columns] if index is None else [index, columns]
append = index is None
indexed = data.set_index(cols, append=append)
else:
if index is None:
index = data.index
else:
index = data[index]
index = MultiIndex.from_arrays([index, data[columns]])
if is_list_like(values) and not isinstance(values, tuple):
# Exclude tuple because it is seen as a single column name
indexed = data._constructor(
data[values].values, index=index, columns=values
)
else:
indexed = data._constructor_sliced(data[values].values, index=index)
return indexed.unstack(columns)
def crosstab(
index,
columns,
values=None,
rownames=None,
colnames=None,
aggfunc=None,
margins=False,
margins_name: str = "All",
dropna: bool = True,
normalize=False,
):
"""
Compute a simple cross tabulation of two (or more) factors. By default
computes a frequency table of the factors unless an array of values and an
aggregation function are passed.
Parameters
----------
index : array-like, Series, or list of arrays/Series
Values to group by in the rows.
columns : array-like, Series, or list of arrays/Series
Values to group by in the columns.
values : array-like, optional
Array of values to aggregate according to the factors.
Requires `aggfunc` be specified.
rownames : sequence, default None
If passed, must match number of row arrays passed.
colnames : sequence, default None
If passed, must match number of column arrays passed.
aggfunc : function, optional
If specified, requires `values` be specified as well.
margins : bool, default False
Add row/column margins (subtotals).
margins_name : str, default 'All'
Name of the row/column that will contain the totals
when margins is True.
.. versionadded:: 0.21.0
dropna : bool, default True
Do not include columns whose entries are all NaN.
normalize : bool, {'all', 'index', 'columns'}, or {0,1}, default False
Normalize by dividing all values by the sum of values.
- If passed 'all' or `True`, will normalize over all values.
- If passed 'index' will normalize over each row.
- If passed 'columns' will normalize over each column.
- If margins is `True`, will also normalize margin values.
Returns
-------
DataFrame
Cross tabulation of the data.
See Also
--------
DataFrame.pivot : Reshape data based on column values.
pivot_table : Create a pivot table as a DataFrame.
Notes
-----
Any Series passed will have their name attributes used unless row or column
names for the cross-tabulation are specified.
Any input passed containing Categorical data will have **all** of its
categories included in the cross-tabulation, even if the actual data does
not contain any instances of a particular category.
In the event that there aren't overlapping indexes an empty DataFrame will
be returned.
Examples
--------
>>> a = np.array(["foo", "foo", "foo", "foo", "bar", "bar",
... "bar", "bar", "foo", "foo", "foo"], dtype=object)
>>> b = np.array(["one", "one", "one", "two", "one", "one",
... "one", "two", "two", "two", "one"], dtype=object)
>>> c = np.array(["dull", "dull", "shiny", "dull", "dull", "shiny",
... "shiny", "dull", "shiny", "shiny", "shiny"],
... dtype=object)
>>> pd.crosstab(a, [b, c], rownames=['a'], colnames=['b', 'c'])
b one two
c dull shiny dull shiny
a
bar 1 2 1 0
foo 2 2 1 2
Here 'c' and 'f' are not represented in the data and will not be
shown in the output because dropna is True by default. Set
dropna=False to preserve categories with no data.
>>> foo = pd.Categorical(['a', 'b'], categories=['a', 'b', 'c'])
>>> bar = pd.Categorical(['d', 'e'], categories=['d', 'e', 'f'])
>>> pd.crosstab(foo, bar)
col_0 d e
row_0
a 1 0
b 0 1
>>> pd.crosstab(foo, bar, dropna=False)
col_0 d e f
row_0
a 1 0 0
b 0 1 0
c 0 0 0
"""
index = com.maybe_make_list(index)
columns = com.maybe_make_list(columns)
rownames = _get_names(index, rownames, prefix="row")
colnames = _get_names(columns, colnames, prefix="col")
common_idx = None
pass_objs = [x for x in index + columns if isinstance(x, (ABCSeries, ABCDataFrame))]
if pass_objs:
common_idx = get_objs_combined_axis(pass_objs, intersect=True, sort=False)
data: Dict = {}
data.update(zip(rownames, index))
data.update(zip(colnames, columns))
if values is None and aggfunc is not None:
raise ValueError("aggfunc cannot be used without values.")
if values is not None and aggfunc is None:
raise ValueError("values cannot be used without an aggfunc.")
from pandas import DataFrame
df = DataFrame(data, index=common_idx)
if values is None:
df["__dummy__"] = 0
kwargs = {"aggfunc": len, "fill_value": 0}
else:
df["__dummy__"] = values
kwargs = {"aggfunc": aggfunc}
table = df.pivot_table(
"__dummy__",
index=rownames,
columns=colnames,
margins=margins,
margins_name=margins_name,
dropna=dropna,
**kwargs,
)
# Post-process
if normalize is not False:
table = _normalize(
table, normalize=normalize, margins=margins, margins_name=margins_name
)
return table
def _normalize(table, normalize, margins: bool, margins_name="All"):
if not isinstance(normalize, (bool, str)):
axis_subs = {0: "index", 1: "columns"}
try:
normalize = axis_subs[normalize]
except KeyError:
raise ValueError("Not a valid normalize argument")
if margins is False:
# Actual Normalizations
normalizers: Dict[Union[bool, str], Callable] = {
"all": lambda x: x / x.sum(axis=1).sum(axis=0),
"columns": lambda x: x / x.sum(),
"index": lambda x: x.div(x.sum(axis=1), axis=0),
}
normalizers[True] = normalizers["all"]
try:
f = normalizers[normalize]
except KeyError:
raise ValueError("Not a valid normalize argument")
table = f(table)
table = table.fillna(0)
elif margins is True:
# keep index and column of pivoted table
table_index = table.index
table_columns = table.columns
# check if margin name is in (for MI cases) or equal to last
# index/column and save the column and index margin
if (margins_name not in table.iloc[-1, :].name) | (
margins_name != table.iloc[:, -1].name
):
raise ValueError(
"{mname} not in pivoted DataFrame".format(mname=margins_name)
)
column_margin = table.iloc[:-1, -1]
index_margin = table.iloc[-1, :-1]
# keep the core table
table = table.iloc[:-1, :-1]
# Normalize core
table = _normalize(table, normalize=normalize, margins=False)
# Fix Margins
if normalize == "columns":
column_margin = column_margin / column_margin.sum()
table = concat([table, column_margin], axis=1)
table = table.fillna(0)
table.columns = table_columns
elif normalize == "index":
index_margin = index_margin / index_margin.sum()
table = table.append(index_margin)
table = table.fillna(0)
table.index = table_index
elif normalize == "all" or normalize is True:
column_margin = column_margin / column_margin.sum()
index_margin = index_margin / index_margin.sum()
index_margin.loc[margins_name] = 1
table = concat([table, column_margin], axis=1)
table = table.append(index_margin)
table = table.fillna(0)
table.index = table_index
table.columns = table_columns
else:
raise ValueError("Not a valid normalize argument")
else:
raise ValueError("Not a valid margins argument")
return table
def _get_names(arrs, names, prefix: str = "row"):
if names is None:
names = []
for i, arr in enumerate(arrs):
if isinstance(arr, ABCSeries) and arr.name is not None:
names.append(arr.name)
else:
names.append("{prefix}_{i}".format(prefix=prefix, i=i))
else:
if len(names) != len(arrs):
raise AssertionError("arrays and names must have the same length")
if not isinstance(names, list):
names = list(names)
return names
| BugsInPy/BugsInPy/temp/projects/pandas/bug-119-fixed/pandas/pandas/core/reshape/pivot.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-119-buggy/pandas/pandas/core/reshape/pivot.py |
pandas-bug-145 | """
Arithmetic operations for PandasObjects
This is not a public API.
"""
import datetime
import operator
from typing import Any, Callable, Tuple, Union
import numpy as np
from pandas._libs import Timedelta, Timestamp, lib, ops as libops
from pandas.errors import NullFrequencyError
from pandas.util._decorators import Appender
from pandas.core.dtypes.cast import construct_1d_object_array_from_listlike
from pandas.core.dtypes.common import (
ensure_object,
is_bool_dtype,
is_datetime64_dtype,
is_extension_array_dtype,
is_integer_dtype,
is_list_like,
is_object_dtype,
is_scalar,
is_timedelta64_dtype,
)
from pandas.core.dtypes.generic import (
ABCDataFrame,
ABCDatetimeArray,
ABCDatetimeIndex,
ABCExtensionArray,
ABCIndexClass,
ABCSeries,
ABCTimedeltaArray,
ABCTimedeltaIndex,
)
from pandas.core.dtypes.missing import isna, notna
from pandas._typing import ArrayLike
from pandas.core.construction import array, extract_array
from pandas.core.ops.array_ops import (
comp_method_OBJECT_ARRAY,
define_na_arithmetic_op,
na_arithmetic_op,
)
from pandas.core.ops.docstrings import (
_arith_doc_FRAME,
_flex_comp_doc_FRAME,
_make_flex_doc,
_op_descriptions,
)
from pandas.core.ops.invalid import invalid_comparison
from pandas.core.ops.methods import ( # noqa:F401
add_flex_arithmetic_methods,
add_special_arithmetic_methods,
)
from pandas.core.ops.roperator import ( # noqa:F401
radd,
rand_,
rdiv,
rdivmod,
rfloordiv,
rmod,
rmul,
ror_,
rpow,
rsub,
rtruediv,
rxor,
)
# -----------------------------------------------------------------------------
# Ops Wrapping Utilities
def get_op_result_name(left, right):
"""
Find the appropriate name to pin to an operation result. This result
should always be either an Index or a Series.
Parameters
----------
left : {Series, Index}
right : object
Returns
-------
name : object
Usually a string
"""
# `left` is always a Series when called from within ops
if isinstance(right, (ABCSeries, ABCIndexClass)):
name = _maybe_match_name(left, right)
else:
name = left.name
return name
def _maybe_match_name(a, b):
"""
Try to find a name to attach to the result of an operation between
a and b. If only one of these has a `name` attribute, return that
name. Otherwise return a consensus name if they match of None if
they have different names.
Parameters
----------
a : object
b : object
Returns
-------
name : str or None
See Also
--------
pandas.core.common.consensus_name_attr
"""
a_has = hasattr(a, "name")
b_has = hasattr(b, "name")
if a_has and b_has:
if a.name == b.name:
return a.name
else:
# TODO: what if they both have np.nan for their names?
return None
elif a_has:
return a.name
elif b_has:
return b.name
return None
def maybe_upcast_for_op(obj, shape: Tuple[int, ...]):
"""
Cast non-pandas objects to pandas types to unify behavior of arithmetic
and comparison operations.
Parameters
----------
obj: object
shape : tuple[int]
Returns
-------
out : object
Notes
-----
Be careful to call this *after* determining the `name` attribute to be
attached to the result of the arithmetic operation.
"""
from pandas.core.arrays import DatetimeArray, TimedeltaArray
if type(obj) is datetime.timedelta:
# GH#22390 cast up to Timedelta to rely on Timedelta
# implementation; otherwise operation against numeric-dtype
# raises TypeError
return Timedelta(obj)
elif isinstance(obj, np.datetime64):
# GH#28080 numpy casts integer-dtype to datetime64 when doing
# array[int] + datetime64, which we do not allow
if isna(obj):
# Avoid possible ambiguities with pd.NaT
obj = obj.astype("datetime64[ns]")
right = np.broadcast_to(obj, shape)
return DatetimeArray(right)
return Timestamp(obj)
elif isinstance(obj, np.timedelta64):
if isna(obj):
# wrapping timedelta64("NaT") in Timedelta returns NaT,
# which would incorrectly be treated as a datetime-NaT, so
# we broadcast and wrap in a TimedeltaArray
obj = obj.astype("timedelta64[ns]")
right = np.broadcast_to(obj, shape)
return TimedeltaArray(right)
# In particular non-nanosecond timedelta64 needs to be cast to
# nanoseconds, or else we get undesired behavior like
# np.timedelta64(3, 'D') / 2 == np.timedelta64(1, 'D')
return Timedelta(obj)
elif isinstance(obj, np.ndarray) and is_timedelta64_dtype(obj.dtype):
# GH#22390 Unfortunately we need to special-case right-hand
# timedelta64 dtypes because numpy casts integer dtypes to
# timedelta64 when operating with timedelta64
return TimedeltaArray._from_sequence(obj)
return obj
# -----------------------------------------------------------------------------
def _gen_eval_kwargs(name):
"""
Find the keyword arguments to pass to numexpr for the given operation.
Parameters
----------
name : str
Returns
-------
eval_kwargs : dict
Examples
--------
>>> _gen_eval_kwargs("__add__")
{}
>>> _gen_eval_kwargs("rtruediv")
{'reversed': True, 'truediv': True}
"""
kwargs = {}
# Series appear to only pass __add__, __radd__, ...
# but DataFrame gets both these dunder names _and_ non-dunder names
# add, radd, ...
name = name.replace("__", "")
if name.startswith("r"):
if name not in ["radd", "rand", "ror", "rxor"]:
# Exclude commutative operations
kwargs["reversed"] = True
return kwargs
def _get_frame_op_default_axis(name):
"""
Only DataFrame cares about default_axis, specifically:
special methods have default_axis=None and flex methods
have default_axis='columns'.
Parameters
----------
name : str
Returns
-------
default_axis: str or None
"""
if name.replace("__r", "__") in ["__and__", "__or__", "__xor__"]:
# bool methods
return "columns"
elif name.startswith("__"):
# __add__, __mul__, ...
return None
else:
# add, mul, ...
return "columns"
def _get_opstr(op):
"""
Find the operation string, if any, to pass to numexpr for this
operation.
Parameters
----------
op : binary operator
Returns
-------
op_str : string or None
"""
return {
operator.add: "+",
radd: "+",
operator.mul: "*",
rmul: "*",
operator.sub: "-",
rsub: "-",
operator.truediv: "/",
rtruediv: "/",
operator.floordiv: "//",
rfloordiv: "//",
operator.mod: None, # TODO: Why None for mod but '%' for rmod?
rmod: "%",
operator.pow: "**",
rpow: "**",
operator.eq: "==",
operator.ne: "!=",
operator.le: "<=",
operator.lt: "<",
operator.ge: ">=",
operator.gt: ">",
operator.and_: "&",
rand_: "&",
operator.or_: "|",
ror_: "|",
operator.xor: "^",
rxor: "^",
divmod: None,
rdivmod: None,
}[op]
def _get_op_name(op, special):
"""
Find the name to attach to this method according to conventions
for special and non-special methods.
Parameters
----------
op : binary operator
special : bool
Returns
-------
op_name : str
"""
opname = op.__name__.strip("_")
if special:
opname = "__{opname}__".format(opname=opname)
return opname
# -----------------------------------------------------------------------------
# Masking NA values and fallbacks for operations numpy does not support
def fill_binop(left, right, fill_value):
"""
If a non-None fill_value is given, replace null entries in left and right
with this value, but only in positions where _one_ of left/right is null,
not both.
Parameters
----------
left : array-like
right : array-like
fill_value : object
Returns
-------
left : array-like
right : array-like
Notes
-----
Makes copies if fill_value is not None
"""
# TODO: can we make a no-copy implementation?
if fill_value is not None:
left_mask = isna(left)
right_mask = isna(right)
left = left.copy()
right = right.copy()
# one but not both
mask = left_mask ^ right_mask
left[left_mask & mask] = fill_value
right[right_mask & mask] = fill_value
return left, right
def mask_cmp_op(x, y, op):
"""
Apply the function `op` to only non-null points in x and y.
Parameters
----------
x : array-like
y : array-like
op : binary operation
Returns
-------
result : ndarray[bool]
"""
xrav = x.ravel()
result = np.empty(x.size, dtype=bool)
if isinstance(y, (np.ndarray, ABCSeries)):
yrav = y.ravel()
mask = notna(xrav) & notna(yrav)
result[mask] = op(np.array(list(xrav[mask])), np.array(list(yrav[mask])))
else:
mask = notna(xrav)
result[mask] = op(np.array(list(xrav[mask])), y)
if op == operator.ne: # pragma: no cover
np.putmask(result, ~mask, True)
else:
np.putmask(result, ~mask, False)
result = result.reshape(x.shape)
return result
# -----------------------------------------------------------------------------
# Dispatch logic
def should_extension_dispatch(left: ABCSeries, right: Any) -> bool:
"""
Identify cases where Series operation should use dispatch_to_extension_op.
Parameters
----------
left : Series
right : object
Returns
-------
bool
"""
if (
is_extension_array_dtype(left.dtype)
or is_datetime64_dtype(left.dtype)
or is_timedelta64_dtype(left.dtype)
):
return True
if not is_scalar(right) and is_extension_array_dtype(right):
# GH#22378 disallow scalar to exclude e.g. "category", "Int64"
return True
return False
def should_series_dispatch(left, right, op):
"""
Identify cases where a DataFrame operation should dispatch to its
Series counterpart.
Parameters
----------
left : DataFrame
right : DataFrame
op : binary operator
Returns
-------
override : bool
"""
if left._is_mixed_type or right._is_mixed_type:
return True
if not len(left.columns) or not len(right.columns):
# ensure obj.dtypes[0] exists for each obj
return False
ldtype = left.dtypes.iloc[0]
rdtype = right.dtypes.iloc[0]
if (is_timedelta64_dtype(ldtype) and is_integer_dtype(rdtype)) or (
is_timedelta64_dtype(rdtype) and is_integer_dtype(ldtype)
):
# numpy integer dtypes as timedelta64 dtypes in this scenario
return True
if is_datetime64_dtype(ldtype) and is_object_dtype(rdtype):
# in particular case where right is an array of DateOffsets
return True
return False
def dispatch_to_series(left, right, func, str_rep=None, axis=None):
"""
Evaluate the frame operation func(left, right) by evaluating
column-by-column, dispatching to the Series implementation.
Parameters
----------
left : DataFrame
right : scalar or DataFrame
func : arithmetic or comparison operator
str_rep : str or None, default None
axis : {None, 0, 1, "index", "columns"}
Returns
-------
DataFrame
"""
# Note: we use iloc to access columns for compat with cases
# with non-unique columns.
import pandas.core.computation.expressions as expressions
right = lib.item_from_zerodim(right)
if lib.is_scalar(right) or np.ndim(right) == 0:
def column_op(a, b):
return {i: func(a.iloc[:, i], b) for i in range(len(a.columns))}
elif isinstance(right, ABCDataFrame):
assert right._indexed_same(left)
def column_op(a, b):
return {i: func(a.iloc[:, i], b.iloc[:, i]) for i in range(len(a.columns))}
elif isinstance(right, ABCSeries) and axis == "columns":
# We only get here if called via left._combine_match_columns,
# in which case we specifically want to operate row-by-row
assert right.index.equals(left.columns)
def column_op(a, b):
return {i: func(a.iloc[:, i], b.iloc[i]) for i in range(len(a.columns))}
elif isinstance(right, ABCSeries):
assert right.index.equals(left.index) # Handle other cases later
def column_op(a, b):
return {i: func(a.iloc[:, i], b) for i in range(len(a.columns))}
else:
# Remaining cases have less-obvious dispatch rules
raise NotImplementedError(right)
new_data = expressions.evaluate(column_op, str_rep, left, right)
return new_data
def dispatch_to_extension_op(
op,
left: Union[ABCExtensionArray, np.ndarray],
right: Any,
keep_null_freq: bool = False,
):
"""
Assume that left or right is a Series backed by an ExtensionArray,
apply the operator defined by op.
Parameters
----------
op : binary operator
left : ExtensionArray or np.ndarray
right : object
keep_null_freq : bool, default False
Whether to re-raise a NullFrequencyError unchanged, as opposed to
catching and raising TypeError.
Returns
-------
ExtensionArray or np.ndarray
2-tuple of these if op is divmod or rdivmod
"""
# NB: left and right should already be unboxed, so neither should be
# a Series or Index.
if left.dtype.kind in "mM" and isinstance(left, np.ndarray):
# We need to cast datetime64 and timedelta64 ndarrays to
# DatetimeArray/TimedeltaArray. But we avoid wrapping others in
# PandasArray as that behaves poorly with e.g. IntegerArray.
left = array(left)
# The op calls will raise TypeError if the op is not defined
# on the ExtensionArray
try:
res_values = op(left, right)
except NullFrequencyError:
# DatetimeIndex and TimedeltaIndex with freq == None raise ValueError
# on add/sub of integers (or int-like). We re-raise as a TypeError.
if keep_null_freq:
# TODO: remove keep_null_freq after Timestamp+int deprecation
# GH#22535 is enforced
raise
raise TypeError(
"incompatible type for a datetime/timedelta "
"operation [{name}]".format(name=op.__name__)
)
return res_values
# -----------------------------------------------------------------------------
# Series
def _align_method_SERIES(left, right, align_asobject=False):
""" align lhs and rhs Series """
# ToDo: Different from _align_method_FRAME, list, tuple and ndarray
# are not coerced here
# because Series has inconsistencies described in #13637
if isinstance(right, ABCSeries):
# avoid repeated alignment
if not left.index.equals(right.index):
if align_asobject:
# to keep original value's dtype for bool ops
left = left.astype(object)
right = right.astype(object)
left, right = left.align(right, copy=False)
return left, right
def _construct_result(left, result, index, name, dtype=None):
"""
If the raw op result has a non-None name (e.g. it is an Index object) and
the name argument is None, then passing name to the constructor will
not be enough; we still need to override the name attribute.
"""
out = left._constructor(result, index=index, dtype=dtype)
out = out.__finalize__(left)
out.name = name
return out
def _construct_divmod_result(left, result, index, name, dtype=None):
"""divmod returns a tuple of like indexed series instead of a single series.
"""
return (
_construct_result(left, result[0], index=index, name=name, dtype=dtype),
_construct_result(left, result[1], index=index, name=name, dtype=dtype),
)
def _arith_method_SERIES(cls, op, special):
"""
Wrapper function for Series arithmetic operations, to avoid
code duplication.
"""
str_rep = _get_opstr(op)
op_name = _get_op_name(op, special)
eval_kwargs = _gen_eval_kwargs(op_name)
construct_result = (
_construct_divmod_result if op in [divmod, rdivmod] else _construct_result
)
def wrapper(left, right):
if isinstance(right, ABCDataFrame):
return NotImplemented
left, right = _align_method_SERIES(left, right)
res_name = get_op_result_name(left, right)
keep_null_freq = isinstance(
right,
(
ABCDatetimeIndex,
ABCDatetimeArray,
ABCTimedeltaIndex,
ABCTimedeltaArray,
Timestamp,
),
)
lvalues = extract_array(left, extract_numpy=True)
rvalues = extract_array(right, extract_numpy=True)
rvalues = maybe_upcast_for_op(rvalues, lvalues.shape)
if should_extension_dispatch(left, rvalues) or isinstance(
rvalues, (ABCTimedeltaArray, ABCDatetimeArray, Timestamp)
):
result = dispatch_to_extension_op(op, lvalues, rvalues, keep_null_freq)
else:
with np.errstate(all="ignore"):
result = na_arithmetic_op(lvalues, rvalues, op, str_rep, eval_kwargs)
# We do not pass dtype to ensure that the Series constructor
# does inference in the case where `result` has object-dtype.
return construct_result(left, result, index=left.index, name=res_name)
wrapper.__name__ = op_name
return wrapper
def _comp_method_SERIES(cls, op, special):
"""
Wrapper function for Series arithmetic operations, to avoid
code duplication.
"""
op_name = _get_op_name(op, special)
def wrapper(self, other):
res_name = get_op_result_name(self, other)
# TODO: shouldn't we be applying finalize whenever
# not isinstance(other, ABCSeries)?
finalizer = (
lambda x: x.__finalize__(self)
if isinstance(other, (np.ndarray, ABCIndexClass))
else x
)
if isinstance(other, ABCDataFrame): # pragma: no cover
# Defer to DataFrame implementation; fail early
return NotImplemented
if isinstance(other, ABCSeries) and not self._indexed_same(other):
raise ValueError("Can only compare identically-labeled Series objects")
other = lib.item_from_zerodim(other)
if isinstance(other, list):
# TODO: same for tuples?
other = np.asarray(other)
if isinstance(other, (np.ndarray, ABCExtensionArray, ABCIndexClass)):
# TODO: make this treatment consistent across ops and classes.
# We are not catching all listlikes here (e.g. frozenset, tuple)
# The ambiguous case is object-dtype. See GH#27803
if len(self) != len(other):
raise ValueError("Lengths must match to compare")
lvalues = extract_array(self, extract_numpy=True)
rvalues = extract_array(other, extract_numpy=True)
if should_extension_dispatch(lvalues, rvalues):
res_values = dispatch_to_extension_op(op, lvalues, rvalues)
elif is_scalar(rvalues) and isna(rvalues):
# numpy does not like comparisons vs None
if op is operator.ne:
res_values = np.ones(len(lvalues), dtype=bool)
else:
res_values = np.zeros(len(lvalues), dtype=bool)
elif is_object_dtype(lvalues.dtype):
res_values = comp_method_OBJECT_ARRAY(op, lvalues, rvalues)
else:
op_name = "__{op}__".format(op=op.__name__)
method = getattr(lvalues, op_name)
with np.errstate(all="ignore"):
res_values = method(rvalues)
if res_values is NotImplemented:
res_values = invalid_comparison(lvalues, rvalues, op)
if is_scalar(res_values):
raise TypeError(
"Could not compare {typ} type with Series".format(typ=type(rvalues))
)
result = self._constructor(res_values, index=self.index)
result = finalizer(result)
# Set the result's name after finalizer is called because finalizer
# would set it back to self.name
result.name = res_name
return result
wrapper.__name__ = op_name
return wrapper
def _bool_method_SERIES(cls, op, special):
"""
Wrapper function for Series arithmetic operations, to avoid
code duplication.
"""
op_name = _get_op_name(op, special)
def na_op(x, y):
try:
result = op(x, y)
except TypeError:
assert not isinstance(y, (list, ABCSeries, ABCIndexClass))
if isinstance(y, np.ndarray):
# bool-bool dtype operations should be OK, should not get here
assert not (is_bool_dtype(x.dtype) and is_bool_dtype(y.dtype))
x = ensure_object(x)
y = ensure_object(y)
result = libops.vec_binop(x, y, op)
else:
# let null fall thru
assert lib.is_scalar(y)
if not isna(y):
y = bool(y)
try:
result = libops.scalar_binop(x, y, op)
except (
TypeError,
ValueError,
AttributeError,
OverflowError,
NotImplementedError,
):
raise TypeError(
"cannot compare a dtyped [{dtype}] array "
"with a scalar of type [{typ}]".format(
dtype=x.dtype, typ=type(y).__name__
)
)
return result
fill_int = lambda x: x
def fill_bool(x, left=None):
# if `left` is specifically not-boolean, we do not cast to bool
if x.dtype.kind in ["c", "f", "O"]:
# dtypes that can hold NA
mask = isna(x)
if mask.any():
x = x.astype(object)
x[mask] = False
if left is None or is_bool_dtype(left.dtype):
x = x.astype(bool)
return x
def wrapper(self, other):
is_self_int_dtype = is_integer_dtype(self.dtype)
self, other = _align_method_SERIES(self, other, align_asobject=True)
res_name = get_op_result_name(self, other)
# TODO: shouldn't we be applying finalize whenever
# not isinstance(other, ABCSeries)?
finalizer = (
lambda x: x.__finalize__(self)
if not isinstance(other, (ABCSeries, ABCIndexClass))
else x
)
if isinstance(other, ABCDataFrame):
# Defer to DataFrame implementation; fail early
return NotImplemented
other = lib.item_from_zerodim(other)
if is_list_like(other) and not hasattr(other, "dtype"):
# e.g. list, tuple
other = construct_1d_object_array_from_listlike(other)
lvalues = extract_array(self, extract_numpy=True)
rvalues = extract_array(other, extract_numpy=True)
if should_extension_dispatch(self, rvalues):
res_values = dispatch_to_extension_op(op, lvalues, rvalues)
else:
if isinstance(rvalues, (ABCSeries, ABCIndexClass, np.ndarray)):
is_other_int_dtype = is_integer_dtype(rvalues.dtype)
rvalues = rvalues if is_other_int_dtype else fill_bool(rvalues, lvalues)
else:
# i.e. scalar
is_other_int_dtype = lib.is_integer(rvalues)
# For int vs int `^`, `|`, `&` are bitwise operators and return
# integer dtypes. Otherwise these are boolean ops
filler = fill_int if is_self_int_dtype and is_other_int_dtype else fill_bool
res_values = na_op(lvalues, rvalues)
res_values = filler(res_values)
result = self._constructor(res_values, index=self.index, name=res_name)
return finalizer(result)
wrapper.__name__ = op_name
return wrapper
def _flex_method_SERIES(cls, op, special):
name = _get_op_name(op, special)
doc = _make_flex_doc(name, "series")
@Appender(doc)
def flex_wrapper(self, other, level=None, fill_value=None, axis=0):
# validate axis
if axis is not None:
self._get_axis_number(axis)
if isinstance(other, ABCSeries):
return self._binop(other, op, level=level, fill_value=fill_value)
elif isinstance(other, (np.ndarray, list, tuple)):
if len(other) != len(self):
raise ValueError("Lengths must be equal")
other = self._constructor(other, self.index)
return self._binop(other, op, level=level, fill_value=fill_value)
else:
if fill_value is not None:
self = self.fillna(fill_value)
return self._constructor(op(self, other), self.index).__finalize__(self)
flex_wrapper.__name__ = name
return flex_wrapper
# -----------------------------------------------------------------------------
# DataFrame
def _combine_series_frame(self, other, func, fill_value=None, axis=None, level=None):
"""
Apply binary operator `func` to self, other using alignment and fill
conventions determined by the fill_value, axis, and level kwargs.
Parameters
----------
self : DataFrame
other : Series
func : binary operator
fill_value : object, default None
axis : {0, 1, 'columns', 'index', None}, default None
level : int or None, default None
Returns
-------
result : DataFrame
"""
if fill_value is not None:
raise NotImplementedError(
"fill_value {fill} not supported.".format(fill=fill_value)
)
if axis is not None:
axis = self._get_axis_number(axis)
if axis == 0:
return self._combine_match_index(other, func, level=level)
else:
return self._combine_match_columns(other, func, level=level)
else:
if not len(other):
return self * np.nan
if not len(self):
# Ambiguous case, use _series so works with DataFrame
return self._constructor(
data=self._series, index=self.index, columns=self.columns
)
# default axis is columns
return self._combine_match_columns(other, func, level=level)
def _align_method_FRAME(left, right, axis):
""" convert rhs to meet lhs dims if input is list, tuple or np.ndarray """
def to_series(right):
msg = "Unable to coerce to Series, length must be {req_len}: given {given_len}"
if axis is not None and left._get_axis_name(axis) == "index":
if len(left.index) != len(right):
raise ValueError(
msg.format(req_len=len(left.index), given_len=len(right))
)
right = left._constructor_sliced(right, index=left.index)
else:
if len(left.columns) != len(right):
raise ValueError(
msg.format(req_len=len(left.columns), given_len=len(right))
)
right = left._constructor_sliced(right, index=left.columns)
return right
if isinstance(right, np.ndarray):
if right.ndim == 1:
right = to_series(right)
elif right.ndim == 2:
if right.shape == left.shape:
right = left._constructor(right, index=left.index, columns=left.columns)
elif right.shape[0] == left.shape[0] and right.shape[1] == 1:
# Broadcast across columns
right = np.broadcast_to(right, left.shape)
right = left._constructor(right, index=left.index, columns=left.columns)
elif right.shape[1] == left.shape[1] and right.shape[0] == 1:
# Broadcast along rows
right = to_series(right[0, :])
else:
raise ValueError(
"Unable to coerce to DataFrame, shape "
"must be {req_shape}: given {given_shape}".format(
req_shape=left.shape, given_shape=right.shape
)
)
elif right.ndim > 2:
raise ValueError(
"Unable to coerce to Series/DataFrame, dim "
"must be <= 2: {dim}".format(dim=right.shape)
)
elif is_list_like(right) and not isinstance(right, (ABCSeries, ABCDataFrame)):
# GH17901
right = to_series(right)
return right
def _arith_method_FRAME(cls, op, special):
str_rep = _get_opstr(op)
op_name = _get_op_name(op, special)
eval_kwargs = _gen_eval_kwargs(op_name)
default_axis = _get_frame_op_default_axis(op_name)
na_op = define_na_arithmetic_op(op, str_rep, eval_kwargs)
if op_name in _op_descriptions:
# i.e. include "add" but not "__add__"
doc = _make_flex_doc(op_name, "dataframe")
else:
doc = _arith_doc_FRAME % op_name
@Appender(doc)
def f(self, other, axis=default_axis, level=None, fill_value=None):
other = _align_method_FRAME(self, other, axis)
if isinstance(other, ABCDataFrame):
# Another DataFrame
pass_op = op if should_series_dispatch(self, other, op) else na_op
return self._combine_frame(other, pass_op, fill_value, level)
elif isinstance(other, ABCSeries):
# For these values of `axis`, we end up dispatching to Series op,
# so do not want the masked op.
pass_op = op if axis in [0, "columns", None] else na_op
return _combine_series_frame(
self, other, pass_op, fill_value=fill_value, axis=axis, level=level
)
else:
# in this case we always have `np.ndim(other) == 0`
if fill_value is not None:
self = self.fillna(fill_value)
return self._combine_const(other, op)
f.__name__ = op_name
return f
def _flex_comp_method_FRAME(cls, op, special):
str_rep = _get_opstr(op)
op_name = _get_op_name(op, special)
default_axis = _get_frame_op_default_axis(op_name)
def na_op(x, y):
try:
with np.errstate(invalid="ignore"):
result = op(x, y)
except TypeError:
result = mask_cmp_op(x, y, op)
return result
doc = _flex_comp_doc_FRAME.format(
op_name=op_name, desc=_op_descriptions[op_name]["desc"]
)
@Appender(doc)
def f(self, other, axis=default_axis, level=None):
other = _align_method_FRAME(self, other, axis)
if isinstance(other, ABCDataFrame):
# Another DataFrame
if not self._indexed_same(other):
self, other = self.align(other, "outer", level=level, copy=False)
new_data = dispatch_to_series(self, other, na_op, str_rep)
return self._construct_result(other, new_data, na_op)
elif isinstance(other, ABCSeries):
return _combine_series_frame(
self, other, na_op, fill_value=None, axis=axis, level=level
)
else:
# in this case we always have `np.ndim(other) == 0`
return self._combine_const(other, na_op)
f.__name__ = op_name
return f
def _comp_method_FRAME(cls, func, special):
str_rep = _get_opstr(func)
op_name = _get_op_name(func, special)
@Appender("Wrapper for comparison method {name}".format(name=op_name))
def f(self, other):
other = _align_method_FRAME(self, other, axis=None)
if isinstance(other, ABCDataFrame):
# Another DataFrame
if not self._indexed_same(other):
raise ValueError(
"Can only compare identically-labeled DataFrame objects"
)
new_data = dispatch_to_series(self, other, func, str_rep)
return self._construct_result(other, new_data, func)
elif isinstance(other, ABCSeries):
return _combine_series_frame(
self, other, func, fill_value=None, axis=None, level=None
)
else:
# straight boolean comparisons we want to allow all columns
# (regardless of dtype to pass thru) See #4537 for discussion.
res = self._combine_const(other, func)
return res
f.__name__ = op_name
return f
# -----------------------------------------------------------------------------
# Sparse
def maybe_dispatch_ufunc_to_dunder_op(
self: ArrayLike, ufunc: Callable, method: str, *inputs: ArrayLike, **kwargs: Any
):
"""
Dispatch a ufunc to the equivalent dunder method.
Parameters
----------
self : ArrayLike
The array whose dunder method we dispatch to
ufunc : Callable
A NumPy ufunc
method : {'reduce', 'accumulate', 'reduceat', 'outer', 'at', '__call__'}
inputs : ArrayLike
The input arrays.
kwargs : Any
The additional keyword arguments, e.g. ``out``.
Returns
-------
result : Any
The result of applying the ufunc
"""
# special has the ufuncs we dispatch to the dunder op on
special = {
"add",
"sub",
"mul",
"pow",
"mod",
"floordiv",
"truediv",
"divmod",
"eq",
"ne",
"lt",
"gt",
"le",
"ge",
"remainder",
"matmul",
}
aliases = {
"subtract": "sub",
"multiply": "mul",
"floor_divide": "floordiv",
"true_divide": "truediv",
"power": "pow",
"remainder": "mod",
"divide": "div",
"equal": "eq",
"not_equal": "ne",
"less": "lt",
"less_equal": "le",
"greater": "gt",
"greater_equal": "ge",
}
# For op(., Array) -> Array.__r{op}__
flipped = {
"lt": "__gt__",
"le": "__ge__",
"gt": "__lt__",
"ge": "__le__",
"eq": "__eq__",
"ne": "__ne__",
}
op_name = ufunc.__name__
op_name = aliases.get(op_name, op_name)
def not_implemented(*args, **kwargs):
return NotImplemented
if method == "__call__" and op_name in special and kwargs.get("out") is None:
if isinstance(inputs[0], type(self)):
name = "__{}__".format(op_name)
return getattr(self, name, not_implemented)(inputs[1])
else:
name = flipped.get(op_name, "__r{}__".format(op_name))
return getattr(self, name, not_implemented)(inputs[0])
else:
return NotImplemented
"""
Arithmetic operations for PandasObjects
This is not a public API.
"""
import datetime
import operator
from typing import Any, Callable, Tuple, Union
import numpy as np
from pandas._libs import Timedelta, Timestamp, lib, ops as libops
from pandas.errors import NullFrequencyError
from pandas.util._decorators import Appender
from pandas.core.dtypes.cast import construct_1d_object_array_from_listlike
from pandas.core.dtypes.common import (
ensure_object,
is_bool_dtype,
is_datetime64_dtype,
is_extension_array_dtype,
is_integer_dtype,
is_list_like,
is_object_dtype,
is_scalar,
is_timedelta64_dtype,
)
from pandas.core.dtypes.generic import (
ABCDataFrame,
ABCDatetimeArray,
ABCDatetimeIndex,
ABCExtensionArray,
ABCIndexClass,
ABCSeries,
ABCTimedeltaArray,
ABCTimedeltaIndex,
)
from pandas.core.dtypes.missing import isna, notna
from pandas._typing import ArrayLike
from pandas.core.construction import array, extract_array
from pandas.core.ops.array_ops import (
comp_method_OBJECT_ARRAY,
define_na_arithmetic_op,
na_arithmetic_op,
)
from pandas.core.ops.docstrings import (
_arith_doc_FRAME,
_flex_comp_doc_FRAME,
_make_flex_doc,
_op_descriptions,
)
from pandas.core.ops.invalid import invalid_comparison
from pandas.core.ops.methods import ( # noqa:F401
add_flex_arithmetic_methods,
add_special_arithmetic_methods,
)
from pandas.core.ops.roperator import ( # noqa:F401
radd,
rand_,
rdiv,
rdivmod,
rfloordiv,
rmod,
rmul,
ror_,
rpow,
rsub,
rtruediv,
rxor,
)
# -----------------------------------------------------------------------------
# Ops Wrapping Utilities
def get_op_result_name(left, right):
"""
Find the appropriate name to pin to an operation result. This result
should always be either an Index or a Series.
Parameters
----------
left : {Series, Index}
right : object
Returns
-------
name : object
Usually a string
"""
# `left` is always a Series when called from within ops
if isinstance(right, (ABCSeries, ABCIndexClass)):
name = _maybe_match_name(left, right)
else:
name = left.name
return name
def _maybe_match_name(a, b):
"""
Try to find a name to attach to the result of an operation between
a and b. If only one of these has a `name` attribute, return that
name. Otherwise return a consensus name if they match of None if
they have different names.
Parameters
----------
a : object
b : object
Returns
-------
name : str or None
See Also
--------
pandas.core.common.consensus_name_attr
"""
a_has = hasattr(a, "name")
b_has = hasattr(b, "name")
if a_has and b_has:
if a.name == b.name:
return a.name
else:
# TODO: what if they both have np.nan for their names?
return None
elif a_has:
return a.name
elif b_has:
return b.name
return None
def maybe_upcast_for_op(obj, shape: Tuple[int, ...]):
"""
Cast non-pandas objects to pandas types to unify behavior of arithmetic
and comparison operations.
Parameters
----------
obj: object
shape : tuple[int]
Returns
-------
out : object
Notes
-----
Be careful to call this *after* determining the `name` attribute to be
attached to the result of the arithmetic operation.
"""
from pandas.core.arrays import DatetimeArray, TimedeltaArray
if type(obj) is datetime.timedelta:
# GH#22390 cast up to Timedelta to rely on Timedelta
# implementation; otherwise operation against numeric-dtype
# raises TypeError
return Timedelta(obj)
elif isinstance(obj, np.datetime64):
# GH#28080 numpy casts integer-dtype to datetime64 when doing
# array[int] + datetime64, which we do not allow
if isna(obj):
# Avoid possible ambiguities with pd.NaT
obj = obj.astype("datetime64[ns]")
right = np.broadcast_to(obj, shape)
return DatetimeArray(right)
return Timestamp(obj)
elif isinstance(obj, np.timedelta64):
if isna(obj):
# wrapping timedelta64("NaT") in Timedelta returns NaT,
# which would incorrectly be treated as a datetime-NaT, so
# we broadcast and wrap in a TimedeltaArray
obj = obj.astype("timedelta64[ns]")
right = np.broadcast_to(obj, shape)
return TimedeltaArray(right)
# In particular non-nanosecond timedelta64 needs to be cast to
# nanoseconds, or else we get undesired behavior like
# np.timedelta64(3, 'D') / 2 == np.timedelta64(1, 'D')
return Timedelta(obj)
elif isinstance(obj, np.ndarray) and is_timedelta64_dtype(obj.dtype):
# GH#22390 Unfortunately we need to special-case right-hand
# timedelta64 dtypes because numpy casts integer dtypes to
# timedelta64 when operating with timedelta64
return TimedeltaArray._from_sequence(obj)
return obj
# -----------------------------------------------------------------------------
def _gen_eval_kwargs(name):
"""
Find the keyword arguments to pass to numexpr for the given operation.
Parameters
----------
name : str
Returns
-------
eval_kwargs : dict
Examples
--------
>>> _gen_eval_kwargs("__add__")
{}
>>> _gen_eval_kwargs("rtruediv")
{'reversed': True, 'truediv': True}
"""
kwargs = {}
# Series appear to only pass __add__, __radd__, ...
# but DataFrame gets both these dunder names _and_ non-dunder names
# add, radd, ...
name = name.replace("__", "")
if name.startswith("r"):
if name not in ["radd", "rand", "ror", "rxor"]:
# Exclude commutative operations
kwargs["reversed"] = True
return kwargs
def _get_frame_op_default_axis(name):
"""
Only DataFrame cares about default_axis, specifically:
special methods have default_axis=None and flex methods
have default_axis='columns'.
Parameters
----------
name : str
Returns
-------
default_axis: str or None
"""
if name.replace("__r", "__") in ["__and__", "__or__", "__xor__"]:
# bool methods
return "columns"
elif name.startswith("__"):
# __add__, __mul__, ...
return None
else:
# add, mul, ...
return "columns"
def _get_opstr(op):
"""
Find the operation string, if any, to pass to numexpr for this
operation.
Parameters
----------
op : binary operator
Returns
-------
op_str : string or None
"""
return {
operator.add: "+",
radd: "+",
operator.mul: "*",
rmul: "*",
operator.sub: "-",
rsub: "-",
operator.truediv: "/",
rtruediv: "/",
operator.floordiv: "//",
rfloordiv: "//",
operator.mod: None, # TODO: Why None for mod but '%' for rmod?
rmod: "%",
operator.pow: "**",
rpow: "**",
operator.eq: "==",
operator.ne: "!=",
operator.le: "<=",
operator.lt: "<",
operator.ge: ">=",
operator.gt: ">",
operator.and_: "&",
rand_: "&",
operator.or_: "|",
ror_: "|",
operator.xor: "^",
rxor: "^",
divmod: None,
rdivmod: None,
}[op]
def _get_op_name(op, special):
"""
Find the name to attach to this method according to conventions
for special and non-special methods.
Parameters
----------
op : binary operator
special : bool
Returns
-------
op_name : str
"""
opname = op.__name__.strip("_")
if special:
opname = "__{opname}__".format(opname=opname)
return opname
# -----------------------------------------------------------------------------
# Masking NA values and fallbacks for operations numpy does not support
def fill_binop(left, right, fill_value):
"""
If a non-None fill_value is given, replace null entries in left and right
with this value, but only in positions where _one_ of left/right is null,
not both.
Parameters
----------
left : array-like
right : array-like
fill_value : object
Returns
-------
left : array-like
right : array-like
Notes
-----
Makes copies if fill_value is not None
"""
# TODO: can we make a no-copy implementation?
if fill_value is not None:
left_mask = isna(left)
right_mask = isna(right)
left = left.copy()
right = right.copy()
# one but not both
mask = left_mask ^ right_mask
left[left_mask & mask] = fill_value
right[right_mask & mask] = fill_value
return left, right
def mask_cmp_op(x, y, op):
"""
Apply the function `op` to only non-null points in x and y.
Parameters
----------
x : array-like
y : array-like
op : binary operation
Returns
-------
result : ndarray[bool]
"""
xrav = x.ravel()
result = np.empty(x.size, dtype=bool)
if isinstance(y, (np.ndarray, ABCSeries)):
yrav = y.ravel()
mask = notna(xrav) & notna(yrav)
result[mask] = op(np.array(list(xrav[mask])), np.array(list(yrav[mask])))
else:
mask = notna(xrav)
result[mask] = op(np.array(list(xrav[mask])), y)
if op == operator.ne: # pragma: no cover
np.putmask(result, ~mask, True)
else:
np.putmask(result, ~mask, False)
result = result.reshape(x.shape)
return result
# -----------------------------------------------------------------------------
# Dispatch logic
def should_extension_dispatch(left: ABCSeries, right: Any) -> bool:
"""
Identify cases where Series operation should use dispatch_to_extension_op.
Parameters
----------
left : Series
right : object
Returns
-------
bool
"""
if (
is_extension_array_dtype(left.dtype)
or is_datetime64_dtype(left.dtype)
or is_timedelta64_dtype(left.dtype)
):
return True
if not is_scalar(right) and is_extension_array_dtype(right):
# GH#22378 disallow scalar to exclude e.g. "category", "Int64"
return True
return False
def should_series_dispatch(left, right, op):
"""
Identify cases where a DataFrame operation should dispatch to its
Series counterpart.
Parameters
----------
left : DataFrame
right : DataFrame
op : binary operator
Returns
-------
override : bool
"""
if left._is_mixed_type or right._is_mixed_type:
return True
if not len(left.columns) or not len(right.columns):
# ensure obj.dtypes[0] exists for each obj
return False
ldtype = left.dtypes.iloc[0]
rdtype = right.dtypes.iloc[0]
if (is_timedelta64_dtype(ldtype) and is_integer_dtype(rdtype)) or (
is_timedelta64_dtype(rdtype) and is_integer_dtype(ldtype)
):
# numpy integer dtypes as timedelta64 dtypes in this scenario
return True
if is_datetime64_dtype(ldtype) and is_object_dtype(rdtype):
# in particular case where right is an array of DateOffsets
return True
return False
def dispatch_to_series(left, right, func, str_rep=None, axis=None):
"""
Evaluate the frame operation func(left, right) by evaluating
column-by-column, dispatching to the Series implementation.
Parameters
----------
left : DataFrame
right : scalar or DataFrame
func : arithmetic or comparison operator
str_rep : str or None, default None
axis : {None, 0, 1, "index", "columns"}
Returns
-------
DataFrame
"""
# Note: we use iloc to access columns for compat with cases
# with non-unique columns.
import pandas.core.computation.expressions as expressions
right = lib.item_from_zerodim(right)
if lib.is_scalar(right) or np.ndim(right) == 0:
def column_op(a, b):
return {i: func(a.iloc[:, i], b) for i in range(len(a.columns))}
elif isinstance(right, ABCDataFrame):
assert right._indexed_same(left)
def column_op(a, b):
return {i: func(a.iloc[:, i], b.iloc[:, i]) for i in range(len(a.columns))}
elif isinstance(right, ABCSeries) and axis == "columns":
# We only get here if called via left._combine_match_columns,
# in which case we specifically want to operate row-by-row
assert right.index.equals(left.columns)
if right.dtype == "timedelta64[ns]":
# ensure we treat NaT values as the correct dtype
# Note: we do not do this unconditionally as it may be lossy or
# expensive for EA dtypes.
right = np.asarray(right)
def column_op(a, b):
return {i: func(a.iloc[:, i], b[i]) for i in range(len(a.columns))}
else:
def column_op(a, b):
return {i: func(a.iloc[:, i], b.iloc[i]) for i in range(len(a.columns))}
elif isinstance(right, ABCSeries):
assert right.index.equals(left.index) # Handle other cases later
def column_op(a, b):
return {i: func(a.iloc[:, i], b) for i in range(len(a.columns))}
else:
# Remaining cases have less-obvious dispatch rules
raise NotImplementedError(right)
new_data = expressions.evaluate(column_op, str_rep, left, right)
return new_data
def dispatch_to_extension_op(
op,
left: Union[ABCExtensionArray, np.ndarray],
right: Any,
keep_null_freq: bool = False,
):
"""
Assume that left or right is a Series backed by an ExtensionArray,
apply the operator defined by op.
Parameters
----------
op : binary operator
left : ExtensionArray or np.ndarray
right : object
keep_null_freq : bool, default False
Whether to re-raise a NullFrequencyError unchanged, as opposed to
catching and raising TypeError.
Returns
-------
ExtensionArray or np.ndarray
2-tuple of these if op is divmod or rdivmod
"""
# NB: left and right should already be unboxed, so neither should be
# a Series or Index.
if left.dtype.kind in "mM" and isinstance(left, np.ndarray):
# We need to cast datetime64 and timedelta64 ndarrays to
# DatetimeArray/TimedeltaArray. But we avoid wrapping others in
# PandasArray as that behaves poorly with e.g. IntegerArray.
left = array(left)
# The op calls will raise TypeError if the op is not defined
# on the ExtensionArray
try:
res_values = op(left, right)
except NullFrequencyError:
# DatetimeIndex and TimedeltaIndex with freq == None raise ValueError
# on add/sub of integers (or int-like). We re-raise as a TypeError.
if keep_null_freq:
# TODO: remove keep_null_freq after Timestamp+int deprecation
# GH#22535 is enforced
raise
raise TypeError(
"incompatible type for a datetime/timedelta "
"operation [{name}]".format(name=op.__name__)
)
return res_values
# -----------------------------------------------------------------------------
# Series
def _align_method_SERIES(left, right, align_asobject=False):
""" align lhs and rhs Series """
# ToDo: Different from _align_method_FRAME, list, tuple and ndarray
# are not coerced here
# because Series has inconsistencies described in #13637
if isinstance(right, ABCSeries):
# avoid repeated alignment
if not left.index.equals(right.index):
if align_asobject:
# to keep original value's dtype for bool ops
left = left.astype(object)
right = right.astype(object)
left, right = left.align(right, copy=False)
return left, right
def _construct_result(left, result, index, name, dtype=None):
"""
If the raw op result has a non-None name (e.g. it is an Index object) and
the name argument is None, then passing name to the constructor will
not be enough; we still need to override the name attribute.
"""
out = left._constructor(result, index=index, dtype=dtype)
out = out.__finalize__(left)
out.name = name
return out
def _construct_divmod_result(left, result, index, name, dtype=None):
"""divmod returns a tuple of like indexed series instead of a single series.
"""
return (
_construct_result(left, result[0], index=index, name=name, dtype=dtype),
_construct_result(left, result[1], index=index, name=name, dtype=dtype),
)
def _arith_method_SERIES(cls, op, special):
"""
Wrapper function for Series arithmetic operations, to avoid
code duplication.
"""
str_rep = _get_opstr(op)
op_name = _get_op_name(op, special)
eval_kwargs = _gen_eval_kwargs(op_name)
construct_result = (
_construct_divmod_result if op in [divmod, rdivmod] else _construct_result
)
def wrapper(left, right):
if isinstance(right, ABCDataFrame):
return NotImplemented
left, right = _align_method_SERIES(left, right)
res_name = get_op_result_name(left, right)
keep_null_freq = isinstance(
right,
(
ABCDatetimeIndex,
ABCDatetimeArray,
ABCTimedeltaIndex,
ABCTimedeltaArray,
Timestamp,
),
)
lvalues = extract_array(left, extract_numpy=True)
rvalues = extract_array(right, extract_numpy=True)
rvalues = maybe_upcast_for_op(rvalues, lvalues.shape)
if should_extension_dispatch(left, rvalues) or isinstance(
rvalues, (ABCTimedeltaArray, ABCDatetimeArray, Timestamp)
):
result = dispatch_to_extension_op(op, lvalues, rvalues, keep_null_freq)
else:
with np.errstate(all="ignore"):
result = na_arithmetic_op(lvalues, rvalues, op, str_rep, eval_kwargs)
# We do not pass dtype to ensure that the Series constructor
# does inference in the case where `result` has object-dtype.
return construct_result(left, result, index=left.index, name=res_name)
wrapper.__name__ = op_name
return wrapper
def _comp_method_SERIES(cls, op, special):
"""
Wrapper function for Series arithmetic operations, to avoid
code duplication.
"""
op_name = _get_op_name(op, special)
def wrapper(self, other):
res_name = get_op_result_name(self, other)
# TODO: shouldn't we be applying finalize whenever
# not isinstance(other, ABCSeries)?
finalizer = (
lambda x: x.__finalize__(self)
if isinstance(other, (np.ndarray, ABCIndexClass))
else x
)
if isinstance(other, ABCDataFrame): # pragma: no cover
# Defer to DataFrame implementation; fail early
return NotImplemented
if isinstance(other, ABCSeries) and not self._indexed_same(other):
raise ValueError("Can only compare identically-labeled Series objects")
other = lib.item_from_zerodim(other)
if isinstance(other, list):
# TODO: same for tuples?
other = np.asarray(other)
if isinstance(other, (np.ndarray, ABCExtensionArray, ABCIndexClass)):
# TODO: make this treatment consistent across ops and classes.
# We are not catching all listlikes here (e.g. frozenset, tuple)
# The ambiguous case is object-dtype. See GH#27803
if len(self) != len(other):
raise ValueError("Lengths must match to compare")
lvalues = extract_array(self, extract_numpy=True)
rvalues = extract_array(other, extract_numpy=True)
if should_extension_dispatch(lvalues, rvalues):
res_values = dispatch_to_extension_op(op, lvalues, rvalues)
elif is_scalar(rvalues) and isna(rvalues):
# numpy does not like comparisons vs None
if op is operator.ne:
res_values = np.ones(len(lvalues), dtype=bool)
else:
res_values = np.zeros(len(lvalues), dtype=bool)
elif is_object_dtype(lvalues.dtype):
res_values = comp_method_OBJECT_ARRAY(op, lvalues, rvalues)
else:
op_name = "__{op}__".format(op=op.__name__)
method = getattr(lvalues, op_name)
with np.errstate(all="ignore"):
res_values = method(rvalues)
if res_values is NotImplemented:
res_values = invalid_comparison(lvalues, rvalues, op)
if is_scalar(res_values):
raise TypeError(
"Could not compare {typ} type with Series".format(typ=type(rvalues))
)
result = self._constructor(res_values, index=self.index)
result = finalizer(result)
# Set the result's name after finalizer is called because finalizer
# would set it back to self.name
result.name = res_name
return result
wrapper.__name__ = op_name
return wrapper
def _bool_method_SERIES(cls, op, special):
"""
Wrapper function for Series arithmetic operations, to avoid
code duplication.
"""
op_name = _get_op_name(op, special)
def na_op(x, y):
try:
result = op(x, y)
except TypeError:
assert not isinstance(y, (list, ABCSeries, ABCIndexClass))
if isinstance(y, np.ndarray):
# bool-bool dtype operations should be OK, should not get here
assert not (is_bool_dtype(x.dtype) and is_bool_dtype(y.dtype))
x = ensure_object(x)
y = ensure_object(y)
result = libops.vec_binop(x, y, op)
else:
# let null fall thru
assert lib.is_scalar(y)
if not isna(y):
y = bool(y)
try:
result = libops.scalar_binop(x, y, op)
except (
TypeError,
ValueError,
AttributeError,
OverflowError,
NotImplementedError,
):
raise TypeError(
"cannot compare a dtyped [{dtype}] array "
"with a scalar of type [{typ}]".format(
dtype=x.dtype, typ=type(y).__name__
)
)
return result
fill_int = lambda x: x
def fill_bool(x, left=None):
# if `left` is specifically not-boolean, we do not cast to bool
if x.dtype.kind in ["c", "f", "O"]:
# dtypes that can hold NA
mask = isna(x)
if mask.any():
x = x.astype(object)
x[mask] = False
if left is None or is_bool_dtype(left.dtype):
x = x.astype(bool)
return x
def wrapper(self, other):
is_self_int_dtype = is_integer_dtype(self.dtype)
self, other = _align_method_SERIES(self, other, align_asobject=True)
res_name = get_op_result_name(self, other)
# TODO: shouldn't we be applying finalize whenever
# not isinstance(other, ABCSeries)?
finalizer = (
lambda x: x.__finalize__(self)
if not isinstance(other, (ABCSeries, ABCIndexClass))
else x
)
if isinstance(other, ABCDataFrame):
# Defer to DataFrame implementation; fail early
return NotImplemented
other = lib.item_from_zerodim(other)
if is_list_like(other) and not hasattr(other, "dtype"):
# e.g. list, tuple
other = construct_1d_object_array_from_listlike(other)
lvalues = extract_array(self, extract_numpy=True)
rvalues = extract_array(other, extract_numpy=True)
if should_extension_dispatch(self, rvalues):
res_values = dispatch_to_extension_op(op, lvalues, rvalues)
else:
if isinstance(rvalues, (ABCSeries, ABCIndexClass, np.ndarray)):
is_other_int_dtype = is_integer_dtype(rvalues.dtype)
rvalues = rvalues if is_other_int_dtype else fill_bool(rvalues, lvalues)
else:
# i.e. scalar
is_other_int_dtype = lib.is_integer(rvalues)
# For int vs int `^`, `|`, `&` are bitwise operators and return
# integer dtypes. Otherwise these are boolean ops
filler = fill_int if is_self_int_dtype and is_other_int_dtype else fill_bool
res_values = na_op(lvalues, rvalues)
res_values = filler(res_values)
result = self._constructor(res_values, index=self.index, name=res_name)
return finalizer(result)
wrapper.__name__ = op_name
return wrapper
def _flex_method_SERIES(cls, op, special):
name = _get_op_name(op, special)
doc = _make_flex_doc(name, "series")
@Appender(doc)
def flex_wrapper(self, other, level=None, fill_value=None, axis=0):
# validate axis
if axis is not None:
self._get_axis_number(axis)
if isinstance(other, ABCSeries):
return self._binop(other, op, level=level, fill_value=fill_value)
elif isinstance(other, (np.ndarray, list, tuple)):
if len(other) != len(self):
raise ValueError("Lengths must be equal")
other = self._constructor(other, self.index)
return self._binop(other, op, level=level, fill_value=fill_value)
else:
if fill_value is not None:
self = self.fillna(fill_value)
return self._constructor(op(self, other), self.index).__finalize__(self)
flex_wrapper.__name__ = name
return flex_wrapper
# -----------------------------------------------------------------------------
# DataFrame
def _combine_series_frame(self, other, func, fill_value=None, axis=None, level=None):
"""
Apply binary operator `func` to self, other using alignment and fill
conventions determined by the fill_value, axis, and level kwargs.
Parameters
----------
self : DataFrame
other : Series
func : binary operator
fill_value : object, default None
axis : {0, 1, 'columns', 'index', None}, default None
level : int or None, default None
Returns
-------
result : DataFrame
"""
if fill_value is not None:
raise NotImplementedError(
"fill_value {fill} not supported.".format(fill=fill_value)
)
if axis is not None:
axis = self._get_axis_number(axis)
if axis == 0:
return self._combine_match_index(other, func, level=level)
else:
return self._combine_match_columns(other, func, level=level)
else:
if not len(other):
return self * np.nan
if not len(self):
# Ambiguous case, use _series so works with DataFrame
return self._constructor(
data=self._series, index=self.index, columns=self.columns
)
# default axis is columns
return self._combine_match_columns(other, func, level=level)
def _align_method_FRAME(left, right, axis):
""" convert rhs to meet lhs dims if input is list, tuple or np.ndarray """
def to_series(right):
msg = "Unable to coerce to Series, length must be {req_len}: given {given_len}"
if axis is not None and left._get_axis_name(axis) == "index":
if len(left.index) != len(right):
raise ValueError(
msg.format(req_len=len(left.index), given_len=len(right))
)
right = left._constructor_sliced(right, index=left.index)
else:
if len(left.columns) != len(right):
raise ValueError(
msg.format(req_len=len(left.columns), given_len=len(right))
)
right = left._constructor_sliced(right, index=left.columns)
return right
if isinstance(right, np.ndarray):
if right.ndim == 1:
right = to_series(right)
elif right.ndim == 2:
if right.shape == left.shape:
right = left._constructor(right, index=left.index, columns=left.columns)
elif right.shape[0] == left.shape[0] and right.shape[1] == 1:
# Broadcast across columns
right = np.broadcast_to(right, left.shape)
right = left._constructor(right, index=left.index, columns=left.columns)
elif right.shape[1] == left.shape[1] and right.shape[0] == 1:
# Broadcast along rows
right = to_series(right[0, :])
else:
raise ValueError(
"Unable to coerce to DataFrame, shape "
"must be {req_shape}: given {given_shape}".format(
req_shape=left.shape, given_shape=right.shape
)
)
elif right.ndim > 2:
raise ValueError(
"Unable to coerce to Series/DataFrame, dim "
"must be <= 2: {dim}".format(dim=right.shape)
)
elif is_list_like(right) and not isinstance(right, (ABCSeries, ABCDataFrame)):
# GH17901
right = to_series(right)
return right
def _arith_method_FRAME(cls, op, special):
str_rep = _get_opstr(op)
op_name = _get_op_name(op, special)
eval_kwargs = _gen_eval_kwargs(op_name)
default_axis = _get_frame_op_default_axis(op_name)
na_op = define_na_arithmetic_op(op, str_rep, eval_kwargs)
if op_name in _op_descriptions:
# i.e. include "add" but not "__add__"
doc = _make_flex_doc(op_name, "dataframe")
else:
doc = _arith_doc_FRAME % op_name
@Appender(doc)
def f(self, other, axis=default_axis, level=None, fill_value=None):
other = _align_method_FRAME(self, other, axis)
if isinstance(other, ABCDataFrame):
# Another DataFrame
pass_op = op if should_series_dispatch(self, other, op) else na_op
return self._combine_frame(other, pass_op, fill_value, level)
elif isinstance(other, ABCSeries):
# For these values of `axis`, we end up dispatching to Series op,
# so do not want the masked op.
pass_op = op if axis in [0, "columns", None] else na_op
return _combine_series_frame(
self, other, pass_op, fill_value=fill_value, axis=axis, level=level
)
else:
# in this case we always have `np.ndim(other) == 0`
if fill_value is not None:
self = self.fillna(fill_value)
return self._combine_const(other, op)
f.__name__ = op_name
return f
def _flex_comp_method_FRAME(cls, op, special):
str_rep = _get_opstr(op)
op_name = _get_op_name(op, special)
default_axis = _get_frame_op_default_axis(op_name)
def na_op(x, y):
try:
with np.errstate(invalid="ignore"):
result = op(x, y)
except TypeError:
result = mask_cmp_op(x, y, op)
return result
doc = _flex_comp_doc_FRAME.format(
op_name=op_name, desc=_op_descriptions[op_name]["desc"]
)
@Appender(doc)
def f(self, other, axis=default_axis, level=None):
other = _align_method_FRAME(self, other, axis)
if isinstance(other, ABCDataFrame):
# Another DataFrame
if not self._indexed_same(other):
self, other = self.align(other, "outer", level=level, copy=False)
new_data = dispatch_to_series(self, other, na_op, str_rep)
return self._construct_result(other, new_data, na_op)
elif isinstance(other, ABCSeries):
return _combine_series_frame(
self, other, na_op, fill_value=None, axis=axis, level=level
)
else:
# in this case we always have `np.ndim(other) == 0`
return self._combine_const(other, na_op)
f.__name__ = op_name
return f
def _comp_method_FRAME(cls, func, special):
str_rep = _get_opstr(func)
op_name = _get_op_name(func, special)
@Appender("Wrapper for comparison method {name}".format(name=op_name))
def f(self, other):
other = _align_method_FRAME(self, other, axis=None)
if isinstance(other, ABCDataFrame):
# Another DataFrame
if not self._indexed_same(other):
raise ValueError(
"Can only compare identically-labeled DataFrame objects"
)
new_data = dispatch_to_series(self, other, func, str_rep)
return self._construct_result(other, new_data, func)
elif isinstance(other, ABCSeries):
return _combine_series_frame(
self, other, func, fill_value=None, axis=None, level=None
)
else:
# straight boolean comparisons we want to allow all columns
# (regardless of dtype to pass thru) See #4537 for discussion.
res = self._combine_const(other, func)
return res
f.__name__ = op_name
return f
# -----------------------------------------------------------------------------
# Sparse
def maybe_dispatch_ufunc_to_dunder_op(
self: ArrayLike, ufunc: Callable, method: str, *inputs: ArrayLike, **kwargs: Any
):
"""
Dispatch a ufunc to the equivalent dunder method.
Parameters
----------
self : ArrayLike
The array whose dunder method we dispatch to
ufunc : Callable
A NumPy ufunc
method : {'reduce', 'accumulate', 'reduceat', 'outer', 'at', '__call__'}
inputs : ArrayLike
The input arrays.
kwargs : Any
The additional keyword arguments, e.g. ``out``.
Returns
-------
result : Any
The result of applying the ufunc
"""
# special has the ufuncs we dispatch to the dunder op on
special = {
"add",
"sub",
"mul",
"pow",
"mod",
"floordiv",
"truediv",
"divmod",
"eq",
"ne",
"lt",
"gt",
"le",
"ge",
"remainder",
"matmul",
}
aliases = {
"subtract": "sub",
"multiply": "mul",
"floor_divide": "floordiv",
"true_divide": "truediv",
"power": "pow",
"remainder": "mod",
"divide": "div",
"equal": "eq",
"not_equal": "ne",
"less": "lt",
"less_equal": "le",
"greater": "gt",
"greater_equal": "ge",
}
# For op(., Array) -> Array.__r{op}__
flipped = {
"lt": "__gt__",
"le": "__ge__",
"gt": "__lt__",
"ge": "__le__",
"eq": "__eq__",
"ne": "__ne__",
}
op_name = ufunc.__name__
op_name = aliases.get(op_name, op_name)
def not_implemented(*args, **kwargs):
return NotImplemented
if method == "__call__" and op_name in special and kwargs.get("out") is None:
if isinstance(inputs[0], type(self)):
name = "__{}__".format(op_name)
return getattr(self, name, not_implemented)(inputs[1])
else:
name = flipped.get(op_name, "__r{}__".format(op_name))
return getattr(self, name, not_implemented)(inputs[0])
else:
return NotImplemented
| BugsInPy/BugsInPy/temp/projects/pandas/bug-145-fixed/pandas/pandas/core/ops/__init__.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-145-buggy/pandas/pandas/core/ops/__init__.py |
pandas-bug-42 | import bz2
from collections import Counter
from contextlib import contextmanager
from datetime import datetime
from functools import wraps
import gzip
import os
from shutil import rmtree
import string
import tempfile
from typing import Any, Callable, List, Optional, Type, Union, cast
import warnings
import zipfile
import numpy as np
from numpy.random import rand, randn
from pandas._config.localization import ( # noqa:F401
can_set_locale,
get_locales,
set_locale,
)
import pandas._libs.testing as _testing
from pandas._typing import FilePathOrBuffer, FrameOrSeries
from pandas.compat import _get_lzma_file, _import_lzma
from pandas.core.dtypes.common import (
is_bool,
is_categorical_dtype,
is_datetime64_dtype,
is_datetime64tz_dtype,
is_extension_array_dtype,
is_interval_dtype,
is_number,
is_numeric_dtype,
is_period_dtype,
is_sequence,
is_timedelta64_dtype,
needs_i8_conversion,
)
from pandas.core.dtypes.missing import array_equivalent
import pandas as pd
from pandas import (
Categorical,
CategoricalIndex,
DataFrame,
DatetimeIndex,
Index,
IntervalIndex,
MultiIndex,
RangeIndex,
Series,
bdate_range,
)
from pandas.core.algorithms import take_1d
from pandas.core.arrays import (
DatetimeArray,
ExtensionArray,
IntervalArray,
PeriodArray,
TimedeltaArray,
period_array,
)
from pandas.io.common import urlopen
from pandas.io.formats.printing import pprint_thing
lzma = _import_lzma()
_N = 30
_K = 4
_RAISE_NETWORK_ERROR_DEFAULT = False
# set testing_mode
_testing_mode_warnings = (DeprecationWarning, ResourceWarning)
def set_testing_mode():
# set the testing mode filters
testing_mode = os.environ.get("PANDAS_TESTING_MODE", "None")
if "deprecate" in testing_mode:
warnings.simplefilter("always", _testing_mode_warnings)
def reset_testing_mode():
# reset the testing mode filters
testing_mode = os.environ.get("PANDAS_TESTING_MODE", "None")
if "deprecate" in testing_mode:
warnings.simplefilter("ignore", _testing_mode_warnings)
set_testing_mode()
def reset_display_options():
"""
Reset the display options for printing and representing objects.
"""
pd.reset_option("^display.", silent=True)
def round_trip_pickle(
obj: Any, path: Optional[FilePathOrBuffer] = None
) -> FrameOrSeries:
"""
Pickle an object and then read it again.
Parameters
----------
obj : any object
The object to pickle and then re-read.
path : str, path object or file-like object, default None
The path where the pickled object is written and then read.
Returns
-------
pandas object
The original object that was pickled and then re-read.
"""
_path = path
if _path is None:
_path = f"__{rands(10)}__.pickle"
with ensure_clean(_path) as temp_path:
pd.to_pickle(obj, temp_path)
return pd.read_pickle(temp_path)
def round_trip_pathlib(writer, reader, path: Optional[str] = None):
"""
Write an object to file specified by a pathlib.Path and read it back
Parameters
----------
writer : callable bound to pandas object
IO writing function (e.g. DataFrame.to_csv )
reader : callable
IO reading function (e.g. pd.read_csv )
path : str, default None
The path where the object is written and then read.
Returns
-------
pandas object
The original object that was serialized and then re-read.
"""
import pytest
Path = pytest.importorskip("pathlib").Path
if path is None:
path = "___pathlib___"
with ensure_clean(path) as path:
writer(Path(path))
obj = reader(Path(path))
return obj
def round_trip_localpath(writer, reader, path: Optional[str] = None):
"""
Write an object to file specified by a py.path LocalPath and read it back.
Parameters
----------
writer : callable bound to pandas object
IO writing function (e.g. DataFrame.to_csv )
reader : callable
IO reading function (e.g. pd.read_csv )
path : str, default None
The path where the object is written and then read.
Returns
-------
pandas object
The original object that was serialized and then re-read.
"""
import pytest
LocalPath = pytest.importorskip("py.path").local
if path is None:
path = "___localpath___"
with ensure_clean(path) as path:
writer(LocalPath(path))
obj = reader(LocalPath(path))
return obj
@contextmanager
def decompress_file(path, compression):
"""
Open a compressed file and return a file object.
Parameters
----------
path : str
The path where the file is read from.
compression : {'gzip', 'bz2', 'zip', 'xz', None}
Name of the decompression to use
Returns
-------
file object
"""
if compression is None:
f = open(path, "rb")
elif compression == "gzip":
f = gzip.open(path, "rb")
elif compression == "bz2":
f = bz2.BZ2File(path, "rb")
elif compression == "xz":
f = _get_lzma_file(lzma)(path, "rb")
elif compression == "zip":
zip_file = zipfile.ZipFile(path)
zip_names = zip_file.namelist()
if len(zip_names) == 1:
f = zip_file.open(zip_names.pop())
else:
raise ValueError(f"ZIP file {path} error. Only one file per ZIP.")
else:
raise ValueError(f"Unrecognized compression type: {compression}")
try:
yield f
finally:
f.close()
if compression == "zip":
zip_file.close()
def write_to_compressed(compression, path, data, dest="test"):
"""
Write data to a compressed file.
Parameters
----------
compression : {'gzip', 'bz2', 'zip', 'xz'}
The compression type to use.
path : str
The file path to write the data.
data : str
The data to write.
dest : str, default "test"
The destination file (for ZIP only)
Raises
------
ValueError : An invalid compression value was passed in.
"""
if compression == "zip":
import zipfile
compress_method = zipfile.ZipFile
elif compression == "gzip":
import gzip
compress_method = gzip.GzipFile
elif compression == "bz2":
import bz2
compress_method = bz2.BZ2File
elif compression == "xz":
compress_method = _get_lzma_file(lzma)
else:
raise ValueError(f"Unrecognized compression type: {compression}")
if compression == "zip":
mode = "w"
args = (dest, data)
method = "writestr"
else:
mode = "wb"
args = (data,)
method = "write"
with compress_method(path, mode=mode) as f:
getattr(f, method)(*args)
def assert_almost_equal(
left,
right,
check_dtype: Union[bool, str] = "equiv",
check_less_precise: Union[bool, int] = False,
**kwargs,
):
"""
Check that the left and right objects are approximately equal.
By approximately equal, we refer to objects that are numbers or that
contain numbers which may be equivalent to specific levels of precision.
Parameters
----------
left : object
right : object
check_dtype : bool or {'equiv'}, default 'equiv'
Check dtype if both a and b are the same type. If 'equiv' is passed in,
then `RangeIndex` and `Int64Index` are also considered equivalent
when doing type checking.
check_less_precise : bool or int, default False
Specify comparison precision. 5 digits (False) or 3 digits (True)
after decimal points are compared. If int, then specify the number
of digits to compare.
When comparing two numbers, if the first number has magnitude less
than 1e-5, we compare the two numbers directly and check whether
they are equivalent within the specified precision. Otherwise, we
compare the **ratio** of the second number to the first number and
check whether it is equivalent to 1 within the specified precision.
"""
if isinstance(left, pd.Index):
assert_index_equal(
left,
right,
check_exact=False,
exact=check_dtype,
check_less_precise=check_less_precise,
**kwargs,
)
elif isinstance(left, pd.Series):
assert_series_equal(
left,
right,
check_exact=False,
check_dtype=check_dtype,
check_less_precise=check_less_precise,
**kwargs,
)
elif isinstance(left, pd.DataFrame):
assert_frame_equal(
left,
right,
check_exact=False,
check_dtype=check_dtype,
check_less_precise=check_less_precise,
**kwargs,
)
else:
# Other sequences.
if check_dtype:
if is_number(left) and is_number(right):
# Do not compare numeric classes, like np.float64 and float.
pass
elif is_bool(left) and is_bool(right):
# Do not compare bool classes, like np.bool_ and bool.
pass
else:
if isinstance(left, np.ndarray) or isinstance(right, np.ndarray):
obj = "numpy array"
else:
obj = "Input"
assert_class_equal(left, right, obj=obj)
_testing.assert_almost_equal(
left,
right,
check_dtype=check_dtype,
check_less_precise=check_less_precise,
**kwargs,
)
def _check_isinstance(left, right, cls):
"""
Helper method for our assert_* methods that ensures that
the two objects being compared have the right type before
proceeding with the comparison.
Parameters
----------
left : The first object being compared.
right : The second object being compared.
cls : The class type to check against.
Raises
------
AssertionError : Either `left` or `right` is not an instance of `cls`.
"""
cls_name = cls.__name__
if not isinstance(left, cls):
raise AssertionError(
f"{cls_name} Expected type {cls}, found {type(left)} instead"
)
if not isinstance(right, cls):
raise AssertionError(
f"{cls_name} Expected type {cls}, found {type(right)} instead"
)
def assert_dict_equal(left, right, compare_keys: bool = True):
_check_isinstance(left, right, dict)
_testing.assert_dict_equal(left, right, compare_keys=compare_keys)
def randbool(size=(), p: float = 0.5):
return rand(*size) <= p
RANDS_CHARS = np.array(list(string.ascii_letters + string.digits), dtype=(np.str_, 1))
RANDU_CHARS = np.array(
list("".join(map(chr, range(1488, 1488 + 26))) + string.digits),
dtype=(np.unicode_, 1),
)
def rands_array(nchars, size, dtype="O"):
"""
Generate an array of byte strings.
"""
retval = (
np.random.choice(RANDS_CHARS, size=nchars * np.prod(size))
.view((np.str_, nchars))
.reshape(size)
)
return retval.astype(dtype)
def randu_array(nchars, size, dtype="O"):
"""
Generate an array of unicode strings.
"""
retval = (
np.random.choice(RANDU_CHARS, size=nchars * np.prod(size))
.view((np.unicode_, nchars))
.reshape(size)
)
return retval.astype(dtype)
def rands(nchars):
"""
Generate one random byte string.
See `rands_array` if you want to create an array of random strings.
"""
return "".join(np.random.choice(RANDS_CHARS, nchars))
def close(fignum=None):
from matplotlib.pyplot import get_fignums, close as _close
if fignum is None:
for fignum in get_fignums():
_close(fignum)
else:
_close(fignum)
# -----------------------------------------------------------------------------
# contextmanager to ensure the file cleanup
@contextmanager
def ensure_clean(filename=None, return_filelike=False, **kwargs):
"""
Gets a temporary path and agrees to remove on close.
Parameters
----------
filename : str (optional)
if None, creates a temporary file which is then removed when out of
scope. if passed, creates temporary file with filename as ending.
return_filelike : bool (default False)
if True, returns a file-like which is *always* cleaned. Necessary for
savefig and other functions which want to append extensions.
**kwargs
Additional keywords passed in for creating a temporary file.
:meth:`tempFile.TemporaryFile` is used when `return_filelike` is ``True``.
:meth:`tempfile.mkstemp` is used when `return_filelike` is ``False``.
Note that the `filename` parameter will be passed in as the `suffix`
argument to either function.
See Also
--------
tempfile.TemporaryFile
tempfile.mkstemp
"""
filename = filename or ""
fd = None
kwargs["suffix"] = filename
if return_filelike:
f = tempfile.TemporaryFile(**kwargs)
try:
yield f
finally:
f.close()
else:
# Don't generate tempfile if using a path with directory specified.
if len(os.path.dirname(filename)):
raise ValueError("Can't pass a qualified name to ensure_clean()")
try:
fd, filename = tempfile.mkstemp(**kwargs)
except UnicodeEncodeError:
import pytest
pytest.skip("no unicode file names on this system")
try:
yield filename
finally:
try:
os.close(fd)
except OSError:
print(f"Couldn't close file descriptor: {fd} (file: {filename})")
try:
if os.path.exists(filename):
os.remove(filename)
except OSError as e:
print(f"Exception on removing file: {e}")
@contextmanager
def ensure_clean_dir():
"""
Get a temporary directory path and agrees to remove on close.
Yields
------
Temporary directory path
"""
directory_name = tempfile.mkdtemp(suffix="")
try:
yield directory_name
finally:
try:
rmtree(directory_name)
except OSError:
pass
@contextmanager
def ensure_safe_environment_variables():
"""
Get a context manager to safely set environment variables
All changes will be undone on close, hence environment variables set
within this contextmanager will neither persist nor change global state.
"""
saved_environ = dict(os.environ)
try:
yield
finally:
os.environ.clear()
os.environ.update(saved_environ)
# -----------------------------------------------------------------------------
# Comparators
def equalContents(arr1, arr2) -> bool:
"""
Checks if the set of unique elements of arr1 and arr2 are equivalent.
"""
return frozenset(arr1) == frozenset(arr2)
def assert_index_equal(
left: Index,
right: Index,
exact: Union[bool, str] = "equiv",
check_names: bool = True,
check_less_precise: Union[bool, int] = False,
check_exact: bool = True,
check_categorical: bool = True,
obj: str = "Index",
) -> None:
"""
Check that left and right Index are equal.
Parameters
----------
left : Index
right : Index
exact : bool or {'equiv'}, default 'equiv'
Whether to check the Index class, dtype and inferred_type
are identical. If 'equiv', then RangeIndex can be substituted for
Int64Index as well.
check_names : bool, default True
Whether to check the names attribute.
check_less_precise : bool or int, default False
Specify comparison precision. Only used when check_exact is False.
5 digits (False) or 3 digits (True) after decimal points are compared.
If int, then specify the digits to compare.
check_exact : bool, default True
Whether to compare number exactly.
check_categorical : bool, default True
Whether to compare internal Categorical exactly.
obj : str, default 'Index'
Specify object name being compared, internally used to show appropriate
assertion message.
"""
__tracebackhide__ = True
def _check_types(l, r, obj="Index"):
if exact:
assert_class_equal(l, r, exact=exact, obj=obj)
# Skip exact dtype checking when `check_categorical` is False
if check_categorical:
assert_attr_equal("dtype", l, r, obj=obj)
# allow string-like to have different inferred_types
if l.inferred_type in ("string"):
assert r.inferred_type in ("string")
else:
assert_attr_equal("inferred_type", l, r, obj=obj)
def _get_ilevel_values(index, level):
# accept level number only
unique = index.levels[level]
level_codes = index.codes[level]
filled = take_1d(unique._values, level_codes, fill_value=unique._na_value)
values = unique._shallow_copy(filled, name=index.names[level])
return values
# instance validation
_check_isinstance(left, right, Index)
# class / dtype comparison
_check_types(left, right, obj=obj)
# level comparison
if left.nlevels != right.nlevels:
msg1 = f"{obj} levels are different"
msg2 = f"{left.nlevels}, {left}"
msg3 = f"{right.nlevels}, {right}"
raise_assert_detail(obj, msg1, msg2, msg3)
# length comparison
if len(left) != len(right):
msg1 = f"{obj} length are different"
msg2 = f"{len(left)}, {left}"
msg3 = f"{len(right)}, {right}"
raise_assert_detail(obj, msg1, msg2, msg3)
# MultiIndex special comparison for little-friendly error messages
if left.nlevels > 1:
left = cast(MultiIndex, left)
right = cast(MultiIndex, right)
for level in range(left.nlevels):
# cannot use get_level_values here because it can change dtype
llevel = _get_ilevel_values(left, level)
rlevel = _get_ilevel_values(right, level)
lobj = f"MultiIndex level [{level}]"
assert_index_equal(
llevel,
rlevel,
exact=exact,
check_names=check_names,
check_less_precise=check_less_precise,
check_exact=check_exact,
obj=lobj,
)
# get_level_values may change dtype
_check_types(left.levels[level], right.levels[level], obj=obj)
# skip exact index checking when `check_categorical` is False
if check_exact and check_categorical:
if not left.equals(right):
diff = np.sum((left.values != right.values).astype(int)) * 100.0 / len(left)
msg = f"{obj} values are different ({np.round(diff, 5)} %)"
raise_assert_detail(obj, msg, left, right)
else:
_testing.assert_almost_equal(
left.values,
right.values,
check_less_precise=check_less_precise,
check_dtype=exact,
obj=obj,
lobj=left,
robj=right,
)
# metadata comparison
if check_names:
assert_attr_equal("names", left, right, obj=obj)
if isinstance(left, pd.PeriodIndex) or isinstance(right, pd.PeriodIndex):
assert_attr_equal("freq", left, right, obj=obj)
if isinstance(left, pd.IntervalIndex) or isinstance(right, pd.IntervalIndex):
assert_interval_array_equal(left._values, right._values)
if check_categorical:
if is_categorical_dtype(left) or is_categorical_dtype(right):
assert_categorical_equal(left._values, right._values, obj=f"{obj} category")
def assert_class_equal(left, right, exact: Union[bool, str] = True, obj="Input"):
"""
Checks classes are equal.
"""
__tracebackhide__ = True
def repr_class(x):
if isinstance(x, Index):
# return Index as it is to include values in the error message
return x
return type(x).__name__
if exact == "equiv":
if type(left) != type(right):
# allow equivalence of Int64Index/RangeIndex
types = {type(left).__name__, type(right).__name__}
if len(types - {"Int64Index", "RangeIndex"}):
msg = f"{obj} classes are not equivalent"
raise_assert_detail(obj, msg, repr_class(left), repr_class(right))
elif exact:
if type(left) != type(right):
msg = f"{obj} classes are different"
raise_assert_detail(obj, msg, repr_class(left), repr_class(right))
def assert_attr_equal(attr: str, left, right, obj: str = "Attributes"):
"""
Check attributes are equal. Both objects must have attribute.
Parameters
----------
attr : str
Attribute name being compared.
left : object
right : object
obj : str, default 'Attributes'
Specify object name being compared, internally used to show appropriate
assertion message
"""
__tracebackhide__ = True
left_attr = getattr(left, attr)
right_attr = getattr(right, attr)
if left_attr is right_attr:
return True
elif (
is_number(left_attr)
and np.isnan(left_attr)
and is_number(right_attr)
and np.isnan(right_attr)
):
# np.nan
return True
try:
result = left_attr == right_attr
except TypeError:
# datetimetz on rhs may raise TypeError
result = False
if not isinstance(result, bool):
result = result.all()
if result:
return True
else:
msg = f'Attribute "{attr}" are different'
raise_assert_detail(obj, msg, left_attr, right_attr)
def assert_is_valid_plot_return_object(objs):
import matplotlib.pyplot as plt
if isinstance(objs, (pd.Series, np.ndarray)):
for el in objs.ravel():
msg = (
"one of 'objs' is not a matplotlib Axes instance, "
f"type encountered {repr(type(el).__name__)}"
)
assert isinstance(el, (plt.Axes, dict)), msg
else:
msg = (
"objs is neither an ndarray of Artist instances nor a single "
"ArtistArtist instance, tuple, or dict, 'objs' is a "
f"{repr(type(objs).__name__)}"
)
assert isinstance(objs, (plt.Artist, tuple, dict)), msg
def assert_is_sorted(seq):
"""Assert that the sequence is sorted."""
if isinstance(seq, (Index, Series)):
seq = seq.values
# sorting does not change precisions
assert_numpy_array_equal(seq, np.sort(np.array(seq)))
def assert_categorical_equal(
left, right, check_dtype=True, check_category_order=True, obj="Categorical"
):
"""
Test that Categoricals are equivalent.
Parameters
----------
left : Categorical
right : Categorical
check_dtype : bool, default True
Check that integer dtype of the codes are the same
check_category_order : bool, default True
Whether the order of the categories should be compared, which
implies identical integer codes. If False, only the resulting
values are compared. The ordered attribute is
checked regardless.
obj : str, default 'Categorical'
Specify object name being compared, internally used to show appropriate
assertion message
"""
_check_isinstance(left, right, Categorical)
if check_category_order:
assert_index_equal(left.categories, right.categories, obj=f"{obj}.categories")
assert_numpy_array_equal(
left.codes, right.codes, check_dtype=check_dtype, obj=f"{obj}.codes",
)
else:
try:
lc = left.categories.sort_values()
rc = right.categories.sort_values()
except TypeError:
# e.g. '<' not supported between instances of 'int' and 'str'
lc, rc = left.categories, right.categories
assert_index_equal(
lc, rc, obj=f"{obj}.categories",
)
assert_index_equal(
left.categories.take(left.codes),
right.categories.take(right.codes),
obj=f"{obj}.values",
)
assert_attr_equal("ordered", left, right, obj=obj)
def assert_interval_array_equal(left, right, exact="equiv", obj="IntervalArray"):
"""
Test that two IntervalArrays are equivalent.
Parameters
----------
left, right : IntervalArray
The IntervalArrays to compare.
exact : bool or {'equiv'}, default 'equiv'
Whether to check the Index class, dtype and inferred_type
are identical. If 'equiv', then RangeIndex can be substituted for
Int64Index as well.
obj : str, default 'IntervalArray'
Specify object name being compared, internally used to show appropriate
assertion message
"""
_check_isinstance(left, right, IntervalArray)
assert_index_equal(left.left, right.left, exact=exact, obj=f"{obj}.left")
assert_index_equal(left.right, right.right, exact=exact, obj=f"{obj}.left")
assert_attr_equal("closed", left, right, obj=obj)
def assert_period_array_equal(left, right, obj="PeriodArray"):
_check_isinstance(left, right, PeriodArray)
assert_numpy_array_equal(left._data, right._data, obj=f"{obj}._data")
assert_attr_equal("freq", left, right, obj=obj)
def assert_datetime_array_equal(left, right, obj="DatetimeArray"):
__tracebackhide__ = True
_check_isinstance(left, right, DatetimeArray)
assert_numpy_array_equal(left._data, right._data, obj=f"{obj}._data")
assert_attr_equal("freq", left, right, obj=obj)
assert_attr_equal("tz", left, right, obj=obj)
def assert_timedelta_array_equal(left, right, obj="TimedeltaArray"):
__tracebackhide__ = True
_check_isinstance(left, right, TimedeltaArray)
assert_numpy_array_equal(left._data, right._data, obj=f"{obj}._data")
assert_attr_equal("freq", left, right, obj=obj)
def raise_assert_detail(obj, message, left, right, diff=None):
__tracebackhide__ = True
if isinstance(left, np.ndarray):
left = pprint_thing(left)
elif is_categorical_dtype(left):
left = repr(left)
if isinstance(right, np.ndarray):
right = pprint_thing(right)
elif is_categorical_dtype(right):
right = repr(right)
msg = f"""{obj} are different
{message}
[left]: {left}
[right]: {right}"""
if diff is not None:
msg += f"\n[diff]: {diff}"
raise AssertionError(msg)
def assert_numpy_array_equal(
left,
right,
strict_nan=False,
check_dtype=True,
err_msg=None,
check_same=None,
obj="numpy array",
):
"""
Check that 'np.ndarray' is equivalent.
Parameters
----------
left, right : numpy.ndarray or iterable
The two arrays to be compared.
strict_nan : bool, default False
If True, consider NaN and None to be different.
check_dtype : bool, default True
Check dtype if both a and b are np.ndarray.
err_msg : str, default None
If provided, used as assertion message.
check_same : None|'copy'|'same', default None
Ensure left and right refer/do not refer to the same memory area.
obj : str, default 'numpy array'
Specify object name being compared, internally used to show appropriate
assertion message.
"""
__tracebackhide__ = True
# instance validation
# Show a detailed error message when classes are different
assert_class_equal(left, right, obj=obj)
# both classes must be an np.ndarray
_check_isinstance(left, right, np.ndarray)
def _get_base(obj):
return obj.base if getattr(obj, "base", None) is not None else obj
left_base = _get_base(left)
right_base = _get_base(right)
if check_same == "same":
if left_base is not right_base:
raise AssertionError(f"{repr(left_base)} is not {repr(right_base)}")
elif check_same == "copy":
if left_base is right_base:
raise AssertionError(f"{repr(left_base)} is {repr(right_base)}")
def _raise(left, right, err_msg):
if err_msg is None:
if left.shape != right.shape:
raise_assert_detail(
obj, f"{obj} shapes are different", left.shape, right.shape,
)
diff = 0
for l, r in zip(left, right):
# count up differences
if not array_equivalent(l, r, strict_nan=strict_nan):
diff += 1
diff = diff * 100.0 / left.size
msg = f"{obj} values are different ({np.round(diff, 5)} %)"
raise_assert_detail(obj, msg, left, right)
raise AssertionError(err_msg)
# compare shape and values
if not array_equivalent(left, right, strict_nan=strict_nan):
_raise(left, right, err_msg)
if check_dtype:
if isinstance(left, np.ndarray) and isinstance(right, np.ndarray):
assert_attr_equal("dtype", left, right, obj=obj)
def assert_extension_array_equal(
left, right, check_dtype=True, check_less_precise=False, check_exact=False
):
"""
Check that left and right ExtensionArrays are equal.
Parameters
----------
left, right : ExtensionArray
The two arrays to compare.
check_dtype : bool, default True
Whether to check if the ExtensionArray dtypes are identical.
check_less_precise : bool or int, default False
Specify comparison precision. Only used when check_exact is False.
5 digits (False) or 3 digits (True) after decimal points are compared.
If int, then specify the digits to compare.
check_exact : bool, default False
Whether to compare number exactly.
Notes
-----
Missing values are checked separately from valid values.
A mask of missing values is computed for each and checked to match.
The remaining all-valid values are cast to object dtype and checked.
"""
assert isinstance(left, ExtensionArray), "left is not an ExtensionArray"
assert isinstance(right, ExtensionArray), "right is not an ExtensionArray"
if check_dtype:
assert_attr_equal("dtype", left, right, obj="ExtensionArray")
if hasattr(left, "asi8") and type(right) == type(left):
# Avoid slow object-dtype comparisons
# np.asarray for case where we have a np.MaskedArray
assert_numpy_array_equal(np.asarray(left.asi8), np.asarray(right.asi8))
return
left_na = np.asarray(left.isna())
right_na = np.asarray(right.isna())
assert_numpy_array_equal(left_na, right_na, obj="ExtensionArray NA mask")
left_valid = np.asarray(left[~left_na].astype(object))
right_valid = np.asarray(right[~right_na].astype(object))
if check_exact:
assert_numpy_array_equal(left_valid, right_valid, obj="ExtensionArray")
else:
_testing.assert_almost_equal(
left_valid,
right_valid,
check_dtype=check_dtype,
check_less_precise=check_less_precise,
obj="ExtensionArray",
)
# This could be refactored to use the NDFrame.equals method
def assert_series_equal(
left,
right,
check_dtype=True,
check_index_type="equiv",
check_series_type=True,
check_less_precise=False,
check_names=True,
check_exact=False,
check_datetimelike_compat=False,
check_categorical=True,
check_category_order=True,
obj="Series",
):
"""
Check that left and right Series are equal.
Parameters
----------
left : Series
right : Series
check_dtype : bool, default True
Whether to check the Series dtype is identical.
check_index_type : bool or {'equiv'}, default 'equiv'
Whether to check the Index class, dtype and inferred_type
are identical.
check_series_type : bool, default True
Whether to check the Series class is identical.
check_less_precise : bool or int, default False
Specify comparison precision. Only used when check_exact is False.
5 digits (False) or 3 digits (True) after decimal points are compared.
If int, then specify the digits to compare.
When comparing two numbers, if the first number has magnitude less
than 1e-5, we compare the two numbers directly and check whether
they are equivalent within the specified precision. Otherwise, we
compare the **ratio** of the second number to the first number and
check whether it is equivalent to 1 within the specified precision.
check_names : bool, default True
Whether to check the Series and Index names attribute.
check_exact : bool, default False
Whether to compare number exactly.
check_datetimelike_compat : bool, default False
Compare datetime-like which is comparable ignoring dtype.
check_categorical : bool, default True
Whether to compare internal Categorical exactly.
check_category_order : bool, default True
Whether to compare category order of internal Categoricals.
.. versionadded:: 1.0.2
obj : str, default 'Series'
Specify object name being compared, internally used to show appropriate
assertion message.
"""
__tracebackhide__ = True
# instance validation
_check_isinstance(left, right, Series)
if check_series_type:
assert_class_equal(left, right, obj=obj)
# length comparison
if len(left) != len(right):
msg1 = f"{len(left)}, {left.index}"
msg2 = f"{len(right)}, {right.index}"
raise_assert_detail(obj, "Series length are different", msg1, msg2)
# index comparison
assert_index_equal(
left.index,
right.index,
exact=check_index_type,
check_names=check_names,
check_less_precise=check_less_precise,
check_exact=check_exact,
check_categorical=check_categorical,
obj=f"{obj}.index",
)
if check_dtype:
# We want to skip exact dtype checking when `check_categorical`
# is False. We'll still raise if only one is a `Categorical`,
# regardless of `check_categorical`
if (
is_categorical_dtype(left.dtype)
and is_categorical_dtype(right.dtype)
and not check_categorical
):
pass
else:
assert_attr_equal("dtype", left, right, obj=f"Attributes of {obj}")
if check_exact:
if not is_numeric_dtype(left.dtype):
raise AssertionError("check_exact may only be used with numeric Series")
assert_numpy_array_equal(
left._values, right._values, check_dtype=check_dtype, obj=str(obj)
)
elif check_datetimelike_compat and (
needs_i8_conversion(left.dtype) or needs_i8_conversion(right.dtype)
):
# we want to check only if we have compat dtypes
# e.g. integer and M|m are NOT compat, but we can simply check
# the values in that case
# datetimelike may have different objects (e.g. datetime.datetime
# vs Timestamp) but will compare equal
if not Index(left._values).equals(Index(right._values)):
msg = (
f"[datetimelike_compat=True] {left._values} "
f"is not equal to {right._values}."
)
raise AssertionError(msg)
elif is_interval_dtype(left.dtype) or is_interval_dtype(right.dtype):
assert_interval_array_equal(left.array, right.array)
elif is_categorical_dtype(left.dtype) or is_categorical_dtype(right.dtype):
_testing.assert_almost_equal(
left._values,
right._values,
check_less_precise=check_less_precise,
check_dtype=check_dtype,
obj=str(obj),
)
elif is_extension_array_dtype(left.dtype) or is_extension_array_dtype(right.dtype):
assert_extension_array_equal(left._values, right._values)
elif needs_i8_conversion(left.dtype) or needs_i8_conversion(right.dtype):
# DatetimeArray or TimedeltaArray
assert_extension_array_equal(left._values, right._values)
else:
_testing.assert_almost_equal(
left._values,
right._values,
check_less_precise=check_less_precise,
check_dtype=check_dtype,
obj=str(obj),
)
# metadata comparison
if check_names:
assert_attr_equal("name", left, right, obj=obj)
if check_categorical:
if is_categorical_dtype(left) or is_categorical_dtype(right):
assert_categorical_equal(
left._values,
right._values,
obj=f"{obj} category",
check_category_order=check_category_order,
)
# This could be refactored to use the NDFrame.equals method
def assert_frame_equal(
left,
right,
check_dtype=True,
check_index_type="equiv",
check_column_type="equiv",
check_frame_type=True,
check_less_precise=False,
check_names=True,
by_blocks=False,
check_exact=False,
check_datetimelike_compat=False,
check_categorical=True,
check_like=False,
obj="DataFrame",
):
"""
Check that left and right DataFrame are equal.
This function is intended to compare two DataFrames and output any
differences. Is is mostly intended for use in unit tests.
Additional parameters allow varying the strictness of the
equality checks performed.
Parameters
----------
left : DataFrame
First DataFrame to compare.
right : DataFrame
Second DataFrame to compare.
check_dtype : bool, default True
Whether to check the DataFrame dtype is identical.
check_index_type : bool or {'equiv'}, default 'equiv'
Whether to check the Index class, dtype and inferred_type
are identical.
check_column_type : bool or {'equiv'}, default 'equiv'
Whether to check the columns class, dtype and inferred_type
are identical. Is passed as the ``exact`` argument of
:func:`assert_index_equal`.
check_frame_type : bool, default True
Whether to check the DataFrame class is identical.
check_less_precise : bool or int, default False
Specify comparison precision. Only used when check_exact is False.
5 digits (False) or 3 digits (True) after decimal points are compared.
If int, then specify the digits to compare.
When comparing two numbers, if the first number has magnitude less
than 1e-5, we compare the two numbers directly and check whether
they are equivalent within the specified precision. Otherwise, we
compare the **ratio** of the second number to the first number and
check whether it is equivalent to 1 within the specified precision.
check_names : bool, default True
Whether to check that the `names` attribute for both the `index`
and `column` attributes of the DataFrame is identical.
by_blocks : bool, default False
Specify how to compare internal data. If False, compare by columns.
If True, compare by blocks.
check_exact : bool, default False
Whether to compare number exactly.
check_datetimelike_compat : bool, default False
Compare datetime-like which is comparable ignoring dtype.
check_categorical : bool, default True
Whether to compare internal Categorical exactly.
check_like : bool, default False
If True, ignore the order of index & columns.
Note: index labels must match their respective rows
(same as in columns) - same labels must be with the same data.
obj : str, default 'DataFrame'
Specify object name being compared, internally used to show appropriate
assertion message.
See Also
--------
assert_series_equal : Equivalent method for asserting Series equality.
DataFrame.equals : Check DataFrame equality.
Examples
--------
This example shows comparing two DataFrames that are equal
but with columns of differing dtypes.
>>> from pandas._testing import assert_frame_equal
>>> df1 = pd.DataFrame({'a': [1, 2], 'b': [3, 4]})
>>> df2 = pd.DataFrame({'a': [1, 2], 'b': [3.0, 4.0]})
df1 equals itself.
>>> assert_frame_equal(df1, df1)
df1 differs from df2 as column 'b' is of a different type.
>>> assert_frame_equal(df1, df2)
Traceback (most recent call last):
...
AssertionError: Attributes of DataFrame.iloc[:, 1] (column name="b") are different
Attribute "dtype" are different
[left]: int64
[right]: float64
Ignore differing dtypes in columns with check_dtype.
>>> assert_frame_equal(df1, df2, check_dtype=False)
"""
__tracebackhide__ = True
# instance validation
_check_isinstance(left, right, DataFrame)
if check_frame_type:
assert isinstance(left, type(right))
# assert_class_equal(left, right, obj=obj)
# shape comparison
if left.shape != right.shape:
raise_assert_detail(
obj, f"{obj} shape mismatch", f"{repr(left.shape)}", f"{repr(right.shape)}",
)
if check_like:
left, right = left.reindex_like(right), right
# index comparison
assert_index_equal(
left.index,
right.index,
exact=check_index_type,
check_names=check_names,
check_less_precise=check_less_precise,
check_exact=check_exact,
check_categorical=check_categorical,
obj=f"{obj}.index",
)
# column comparison
assert_index_equal(
left.columns,
right.columns,
exact=check_column_type,
check_names=check_names,
check_less_precise=check_less_precise,
check_exact=check_exact,
check_categorical=check_categorical,
obj=f"{obj}.columns",
)
# compare by blocks
if by_blocks:
rblocks = right._to_dict_of_blocks()
lblocks = left._to_dict_of_blocks()
for dtype in list(set(list(lblocks.keys()) + list(rblocks.keys()))):
assert dtype in lblocks
assert dtype in rblocks
assert_frame_equal(
lblocks[dtype], rblocks[dtype], check_dtype=check_dtype, obj=obj
)
# compare by columns
else:
for i, col in enumerate(left.columns):
assert col in right
lcol = left.iloc[:, i]
rcol = right.iloc[:, i]
assert_series_equal(
lcol,
rcol,
check_dtype=check_dtype,
check_index_type=check_index_type,
check_less_precise=check_less_precise,
check_exact=check_exact,
check_names=check_names,
check_datetimelike_compat=check_datetimelike_compat,
check_categorical=check_categorical,
obj=f'{obj}.iloc[:, {i}] (column name="{col}")',
)
def assert_equal(left, right, **kwargs):
"""
Wrapper for tm.assert_*_equal to dispatch to the appropriate test function.
Parameters
----------
left, right : Index, Series, DataFrame, ExtensionArray, or np.ndarray
The two items to be compared.
**kwargs
All keyword arguments are passed through to the underlying assert method.
"""
__tracebackhide__ = True
if isinstance(left, pd.Index):
assert_index_equal(left, right, **kwargs)
elif isinstance(left, pd.Series):
assert_series_equal(left, right, **kwargs)
elif isinstance(left, pd.DataFrame):
assert_frame_equal(left, right, **kwargs)
elif isinstance(left, IntervalArray):
assert_interval_array_equal(left, right, **kwargs)
elif isinstance(left, PeriodArray):
assert_period_array_equal(left, right, **kwargs)
elif isinstance(left, DatetimeArray):
assert_datetime_array_equal(left, right, **kwargs)
elif isinstance(left, TimedeltaArray):
assert_timedelta_array_equal(left, right, **kwargs)
elif isinstance(left, ExtensionArray):
assert_extension_array_equal(left, right, **kwargs)
elif isinstance(left, np.ndarray):
assert_numpy_array_equal(left, right, **kwargs)
elif isinstance(left, str):
assert kwargs == {}
assert left == right
else:
raise NotImplementedError(type(left))
def box_expected(expected, box_cls, transpose=True):
"""
Helper function to wrap the expected output of a test in a given box_class.
Parameters
----------
expected : np.ndarray, Index, Series
box_cls : {Index, Series, DataFrame}
Returns
-------
subclass of box_cls
"""
if box_cls is pd.Index:
expected = pd.Index(expected)
elif box_cls is pd.Series:
expected = pd.Series(expected)
elif box_cls is pd.DataFrame:
expected = pd.Series(expected).to_frame()
if transpose:
# for vector operations, we we need a DataFrame to be a single-row,
# not a single-column, in order to operate against non-DataFrame
# vectors of the same length.
expected = expected.T
elif box_cls is PeriodArray:
# the PeriodArray constructor is not as flexible as period_array
expected = period_array(expected)
elif box_cls is DatetimeArray:
expected = DatetimeArray(expected)
elif box_cls is TimedeltaArray:
expected = TimedeltaArray(expected)
elif box_cls is np.ndarray:
expected = np.array(expected)
elif box_cls is to_array:
expected = to_array(expected)
else:
raise NotImplementedError(box_cls)
return expected
def to_array(obj):
# temporary implementation until we get pd.array in place
if is_period_dtype(obj):
return period_array(obj)
elif is_datetime64_dtype(obj) or is_datetime64tz_dtype(obj):
return DatetimeArray._from_sequence(obj)
elif is_timedelta64_dtype(obj):
return TimedeltaArray._from_sequence(obj)
else:
return np.array(obj)
# -----------------------------------------------------------------------------
# Sparse
def assert_sp_array_equal(left, right):
"""
Check that the left and right SparseArray are equal.
Parameters
----------
left : SparseArray
right : SparseArray
"""
_check_isinstance(left, right, pd.arrays.SparseArray)
assert_numpy_array_equal(left.sp_values, right.sp_values)
# SparseIndex comparison
assert isinstance(left.sp_index, pd._libs.sparse.SparseIndex)
assert isinstance(right.sp_index, pd._libs.sparse.SparseIndex)
left_index = left.sp_index
right_index = right.sp_index
if not left_index.equals(right_index):
raise_assert_detail(
"SparseArray.index", "index are not equal", left_index, right_index
)
else:
# Just ensure a
pass
assert_attr_equal("fill_value", left, right)
assert_attr_equal("dtype", left, right)
assert_numpy_array_equal(left.to_dense(), right.to_dense())
# -----------------------------------------------------------------------------
# Others
def assert_contains_all(iterable, dic):
for k in iterable:
assert k in dic, f"Did not contain item: {repr(k)}"
def assert_copy(iter1, iter2, **eql_kwargs):
"""
iter1, iter2: iterables that produce elements
comparable with assert_almost_equal
Checks that the elements are equal, but not
the same object. (Does not check that items
in sequences are also not the same object)
"""
for elem1, elem2 in zip(iter1, iter2):
assert_almost_equal(elem1, elem2, **eql_kwargs)
msg = (
f"Expected object {repr(type(elem1))} and object {repr(type(elem2))} to be "
"different objects, but they were the same object."
)
assert elem1 is not elem2, msg
def getCols(k):
return string.ascii_uppercase[:k]
# make index
def makeStringIndex(k=10, name=None):
return Index(rands_array(nchars=10, size=k), name=name)
def makeUnicodeIndex(k=10, name=None):
return Index(randu_array(nchars=10, size=k), name=name)
def makeCategoricalIndex(k=10, n=3, name=None, **kwargs):
""" make a length k index or n categories """
x = rands_array(nchars=4, size=n)
return CategoricalIndex(
Categorical.from_codes(np.arange(k) % n, categories=x), name=name, **kwargs
)
def makeIntervalIndex(k=10, name=None, **kwargs):
""" make a length k IntervalIndex """
x = np.linspace(0, 100, num=(k + 1))
return IntervalIndex.from_breaks(x, name=name, **kwargs)
def makeBoolIndex(k=10, name=None):
if k == 1:
return Index([True], name=name)
elif k == 2:
return Index([False, True], name=name)
return Index([False, True] + [False] * (k - 2), name=name)
def makeIntIndex(k=10, name=None):
return Index(list(range(k)), name=name)
def makeUIntIndex(k=10, name=None):
return Index([2 ** 63 + i for i in range(k)], name=name)
def makeRangeIndex(k=10, name=None, **kwargs):
return RangeIndex(0, k, 1, name=name, **kwargs)
def makeFloatIndex(k=10, name=None):
values = sorted(np.random.random_sample(k)) - np.random.random_sample(1)
return Index(values * (10 ** np.random.randint(0, 9)), name=name)
def makeDateIndex(k=10, freq="B", name=None, **kwargs):
dt = datetime(2000, 1, 1)
dr = bdate_range(dt, periods=k, freq=freq, name=name)
return DatetimeIndex(dr, name=name, **kwargs)
def makeTimedeltaIndex(k=10, freq="D", name=None, **kwargs):
return pd.timedelta_range(start="1 day", periods=k, freq=freq, name=name, **kwargs)
def makePeriodIndex(k=10, name=None, **kwargs):
dt = datetime(2000, 1, 1)
dr = pd.period_range(start=dt, periods=k, freq="B", name=name, **kwargs)
return dr
def makeMultiIndex(k=10, names=None, **kwargs):
return MultiIndex.from_product((("foo", "bar"), (1, 2)), names=names, **kwargs)
_names = [
"Alice",
"Bob",
"Charlie",
"Dan",
"Edith",
"Frank",
"George",
"Hannah",
"Ingrid",
"Jerry",
"Kevin",
"Laura",
"Michael",
"Norbert",
"Oliver",
"Patricia",
"Quinn",
"Ray",
"Sarah",
"Tim",
"Ursula",
"Victor",
"Wendy",
"Xavier",
"Yvonne",
"Zelda",
]
def _make_timeseries(start="2000-01-01", end="2000-12-31", freq="1D", seed=None):
"""
Make a DataFrame with a DatetimeIndex
Parameters
----------
start : str or Timestamp, default "2000-01-01"
The start of the index. Passed to date_range with `freq`.
end : str or Timestamp, default "2000-12-31"
The end of the index. Passed to date_range with `freq`.
freq : str or Freq
The frequency to use for the DatetimeIndex
seed : int, optional
The random state seed.
* name : object dtype with string names
* id : int dtype with
* x, y : float dtype
Examples
--------
>>> _make_timeseries()
id name x y
timestamp
2000-01-01 982 Frank 0.031261 0.986727
2000-01-02 1025 Edith -0.086358 -0.032920
2000-01-03 982 Edith 0.473177 0.298654
2000-01-04 1009 Sarah 0.534344 -0.750377
2000-01-05 963 Zelda -0.271573 0.054424
... ... ... ... ...
2000-12-27 980 Ingrid -0.132333 -0.422195
2000-12-28 972 Frank -0.376007 -0.298687
2000-12-29 1009 Ursula -0.865047 -0.503133
2000-12-30 1000 Hannah -0.063757 -0.507336
2000-12-31 972 Tim -0.869120 0.531685
"""
index = pd.date_range(start=start, end=end, freq=freq, name="timestamp")
n = len(index)
state = np.random.RandomState(seed)
columns = {
"name": state.choice(_names, size=n),
"id": state.poisson(1000, size=n),
"x": state.rand(n) * 2 - 1,
"y": state.rand(n) * 2 - 1,
}
df = pd.DataFrame(columns, index=index, columns=sorted(columns))
if df.index[-1] == end:
df = df.iloc[:-1]
return df
def all_index_generator(k=10):
"""
Generator which can be iterated over to get instances of all the various
index classes.
Parameters
----------
k: length of each of the index instances
"""
all_make_index_funcs = [
makeIntIndex,
makeFloatIndex,
makeStringIndex,
makeUnicodeIndex,
makeDateIndex,
makePeriodIndex,
makeTimedeltaIndex,
makeBoolIndex,
makeRangeIndex,
makeIntervalIndex,
makeCategoricalIndex,
]
for make_index_func in all_make_index_funcs:
yield make_index_func(k=k)
def index_subclass_makers_generator():
make_index_funcs = [
makeDateIndex,
makePeriodIndex,
makeTimedeltaIndex,
makeRangeIndex,
makeIntervalIndex,
makeCategoricalIndex,
makeMultiIndex,
]
for make_index_func in make_index_funcs:
yield make_index_func
def all_timeseries_index_generator(k=10):
"""
Generator which can be iterated over to get instances of all the classes
which represent time-series.
Parameters
----------
k: length of each of the index instances
"""
make_index_funcs = [makeDateIndex, makePeriodIndex, makeTimedeltaIndex]
for make_index_func in make_index_funcs:
yield make_index_func(k=k)
# make series
def makeFloatSeries(name=None):
index = makeStringIndex(_N)
return Series(randn(_N), index=index, name=name)
def makeStringSeries(name=None):
index = makeStringIndex(_N)
return Series(randn(_N), index=index, name=name)
def makeObjectSeries(name=None):
data = makeStringIndex(_N)
data = Index(data, dtype=object)
index = makeStringIndex(_N)
return Series(data, index=index, name=name)
def getSeriesData():
index = makeStringIndex(_N)
return {c: Series(randn(_N), index=index) for c in getCols(_K)}
def makeTimeSeries(nper=None, freq="B", name=None):
if nper is None:
nper = _N
return Series(randn(nper), index=makeDateIndex(nper, freq=freq), name=name)
def makePeriodSeries(nper=None, name=None):
if nper is None:
nper = _N
return Series(randn(nper), index=makePeriodIndex(nper), name=name)
def getTimeSeriesData(nper=None, freq="B"):
return {c: makeTimeSeries(nper, freq) for c in getCols(_K)}
def getPeriodData(nper=None):
return {c: makePeriodSeries(nper) for c in getCols(_K)}
# make frame
def makeTimeDataFrame(nper=None, freq="B"):
data = getTimeSeriesData(nper, freq)
return DataFrame(data)
def makeDataFrame():
data = getSeriesData()
return DataFrame(data)
def getMixedTypeDict():
index = Index(["a", "b", "c", "d", "e"])
data = {
"A": [0.0, 1.0, 2.0, 3.0, 4.0],
"B": [0.0, 1.0, 0.0, 1.0, 0.0],
"C": ["foo1", "foo2", "foo3", "foo4", "foo5"],
"D": bdate_range("1/1/2009", periods=5),
}
return index, data
def makeMixedDataFrame():
return DataFrame(getMixedTypeDict()[1])
def makePeriodFrame(nper=None):
data = getPeriodData(nper)
return DataFrame(data)
def makeCustomIndex(
nentries, nlevels, prefix="#", names=False, ndupe_l=None, idx_type=None
):
"""
Create an index/multindex with given dimensions, levels, names, etc'
nentries - number of entries in index
nlevels - number of levels (> 1 produces multindex)
prefix - a string prefix for labels
names - (Optional), bool or list of strings. if True will use default
names, if false will use no names, if a list is given, the name of
each level in the index will be taken from the list.
ndupe_l - (Optional), list of ints, the number of rows for which the
label will repeated at the corresponding level, you can specify just
the first few, the rest will use the default ndupe_l of 1.
len(ndupe_l) <= nlevels.
idx_type - "i"/"f"/"s"/"u"/"dt"/"p"/"td".
If idx_type is not None, `idx_nlevels` must be 1.
"i"/"f" creates an integer/float index,
"s"/"u" creates a string/unicode index
"dt" create a datetime index.
"td" create a datetime index.
if unspecified, string labels will be generated.
"""
if ndupe_l is None:
ndupe_l = [1] * nlevels
assert is_sequence(ndupe_l) and len(ndupe_l) <= nlevels
assert names is None or names is False or names is True or len(names) is nlevels
assert idx_type is None or (
idx_type in ("i", "f", "s", "u", "dt", "p", "td") and nlevels == 1
)
if names is True:
# build default names
names = [prefix + str(i) for i in range(nlevels)]
if names is False:
# pass None to index constructor for no name
names = None
# make singleton case uniform
if isinstance(names, str) and nlevels == 1:
names = [names]
# specific 1D index type requested?
idx_func = dict(
i=makeIntIndex,
f=makeFloatIndex,
s=makeStringIndex,
u=makeUnicodeIndex,
dt=makeDateIndex,
td=makeTimedeltaIndex,
p=makePeriodIndex,
).get(idx_type)
if idx_func:
idx = idx_func(nentries)
# but we need to fill in the name
if names:
idx.name = names[0]
return idx
elif idx_type is not None:
raise ValueError(
f"{repr(idx_type)} is not a legal value for `idx_type`, "
"use 'i'/'f'/'s'/'u'/'dt'/'p'/'td'."
)
if len(ndupe_l) < nlevels:
ndupe_l.extend([1] * (nlevels - len(ndupe_l)))
assert len(ndupe_l) == nlevels
assert all(x > 0 for x in ndupe_l)
tuples = []
for i in range(nlevels):
def keyfunc(x):
import re
numeric_tuple = re.sub(r"[^\d_]_?", "", x).split("_")
return [int(num) for num in numeric_tuple]
# build a list of lists to create the index from
div_factor = nentries // ndupe_l[i] + 1
cnt = Counter()
for j in range(div_factor):
label = f"{prefix}_l{i}_g{j}"
cnt[label] = ndupe_l[i]
# cute Counter trick
result = sorted(cnt.elements(), key=keyfunc)[:nentries]
tuples.append(result)
tuples = list(zip(*tuples))
# convert tuples to index
if nentries == 1:
# we have a single level of tuples, i.e. a regular Index
index = Index(tuples[0], name=names[0])
elif nlevels == 1:
name = None if names is None else names[0]
index = Index((x[0] for x in tuples), name=name)
else:
index = MultiIndex.from_tuples(tuples, names=names)
return index
def makeCustomDataframe(
nrows,
ncols,
c_idx_names=True,
r_idx_names=True,
c_idx_nlevels=1,
r_idx_nlevels=1,
data_gen_f=None,
c_ndupe_l=None,
r_ndupe_l=None,
dtype=None,
c_idx_type=None,
r_idx_type=None,
):
"""
Create a DataFrame using supplied parameters.
Parameters
----------
nrows, ncols - number of data rows/cols
c_idx_names, idx_names - False/True/list of strings, yields No names ,
default names or uses the provided names for the levels of the
corresponding index. You can provide a single string when
c_idx_nlevels ==1.
c_idx_nlevels - number of levels in columns index. > 1 will yield MultiIndex
r_idx_nlevels - number of levels in rows index. > 1 will yield MultiIndex
data_gen_f - a function f(row,col) which return the data value
at that position, the default generator used yields values of the form
"RxCy" based on position.
c_ndupe_l, r_ndupe_l - list of integers, determines the number
of duplicates for each label at a given level of the corresponding
index. The default `None` value produces a multiplicity of 1 across
all levels, i.e. a unique index. Will accept a partial list of length
N < idx_nlevels, for just the first N levels. If ndupe doesn't divide
nrows/ncol, the last label might have lower multiplicity.
dtype - passed to the DataFrame constructor as is, in case you wish to
have more control in conjunction with a custom `data_gen_f`
r_idx_type, c_idx_type - "i"/"f"/"s"/"u"/"dt"/"td".
If idx_type is not None, `idx_nlevels` must be 1.
"i"/"f" creates an integer/float index,
"s"/"u" creates a string/unicode index
"dt" create a datetime index.
"td" create a timedelta index.
if unspecified, string labels will be generated.
Examples
--------
# 5 row, 3 columns, default names on both, single index on both axis
>> makeCustomDataframe(5,3)
# make the data a random int between 1 and 100
>> mkdf(5,3,data_gen_f=lambda r,c:randint(1,100))
# 2-level multiindex on rows with each label duplicated
# twice on first level, default names on both axis, single
# index on both axis
>> a=makeCustomDataframe(5,3,r_idx_nlevels=2,r_ndupe_l=[2])
# DatetimeIndex on row, index with unicode labels on columns
# no names on either axis
>> a=makeCustomDataframe(5,3,c_idx_names=False,r_idx_names=False,
r_idx_type="dt",c_idx_type="u")
# 4-level multindex on rows with names provided, 2-level multindex
# on columns with default labels and default names.
>> a=makeCustomDataframe(5,3,r_idx_nlevels=4,
r_idx_names=["FEE","FI","FO","FAM"],
c_idx_nlevels=2)
>> a=mkdf(5,3,r_idx_nlevels=2,c_idx_nlevels=4)
"""
assert c_idx_nlevels > 0
assert r_idx_nlevels > 0
assert r_idx_type is None or (
r_idx_type in ("i", "f", "s", "u", "dt", "p", "td") and r_idx_nlevels == 1
)
assert c_idx_type is None or (
c_idx_type in ("i", "f", "s", "u", "dt", "p", "td") and c_idx_nlevels == 1
)
columns = makeCustomIndex(
ncols,
nlevels=c_idx_nlevels,
prefix="C",
names=c_idx_names,
ndupe_l=c_ndupe_l,
idx_type=c_idx_type,
)
index = makeCustomIndex(
nrows,
nlevels=r_idx_nlevels,
prefix="R",
names=r_idx_names,
ndupe_l=r_ndupe_l,
idx_type=r_idx_type,
)
# by default, generate data based on location
if data_gen_f is None:
data_gen_f = lambda r, c: f"R{r}C{c}"
data = [[data_gen_f(r, c) for c in range(ncols)] for r in range(nrows)]
return DataFrame(data, index, columns, dtype=dtype)
def _create_missing_idx(nrows, ncols, density, random_state=None):
if random_state is None:
random_state = np.random
else:
random_state = np.random.RandomState(random_state)
# below is cribbed from scipy.sparse
size = int(np.round((1 - density) * nrows * ncols))
# generate a few more to ensure unique values
min_rows = 5
fac = 1.02
extra_size = min(size + min_rows, fac * size)
def _gen_unique_rand(rng, _extra_size):
ind = rng.rand(int(_extra_size))
return np.unique(np.floor(ind * nrows * ncols))[:size]
ind = _gen_unique_rand(random_state, extra_size)
while ind.size < size:
extra_size *= 1.05
ind = _gen_unique_rand(random_state, extra_size)
j = np.floor(ind * 1.0 / nrows).astype(int)
i = (ind - j * nrows).astype(int)
return i.tolist(), j.tolist()
def makeMissingDataframe(density=0.9, random_state=None):
df = makeDataFrame()
i, j = _create_missing_idx(*df.shape, density=density, random_state=random_state)
df.values[i, j] = np.nan
return df
def optional_args(decorator):
"""
allows a decorator to take optional positional and keyword arguments.
Assumes that taking a single, callable, positional argument means that
it is decorating a function, i.e. something like this::
@my_decorator
def function(): pass
Calls decorator with decorator(f, *args, **kwargs)
"""
@wraps(decorator)
def wrapper(*args, **kwargs):
def dec(f):
return decorator(f, *args, **kwargs)
is_decorating = not kwargs and len(args) == 1 and callable(args[0])
if is_decorating:
f = args[0]
args = []
return dec(f)
else:
return dec
return wrapper
# skip tests on exceptions with this message
_network_error_messages = (
# 'urlopen error timed out',
# 'timeout: timed out',
# 'socket.timeout: timed out',
"timed out",
"Server Hangup",
"HTTP Error 503: Service Unavailable",
"502: Proxy Error",
"HTTP Error 502: internal error",
"HTTP Error 502",
"HTTP Error 503",
"HTTP Error 403",
"HTTP Error 400",
"Temporary failure in name resolution",
"Name or service not known",
"Connection refused",
"certificate verify",
)
# or this e.errno/e.reason.errno
_network_errno_vals = (
101, # Network is unreachable
111, # Connection refused
110, # Connection timed out
104, # Connection reset Error
54, # Connection reset by peer
60, # urllib.error.URLError: [Errno 60] Connection timed out
)
# Both of the above shouldn't mask real issues such as 404's
# or refused connections (changed DNS).
# But some tests (test_data yahoo) contact incredibly flakey
# servers.
# and conditionally raise on exception types in _get_default_network_errors
def _get_default_network_errors():
# Lazy import for http.client because it imports many things from the stdlib
import http.client
return (IOError, http.client.HTTPException, TimeoutError)
def can_connect(url, error_classes=None):
"""
Try to connect to the given url. True if succeeds, False if IOError
raised
Parameters
----------
url : basestring
The URL to try to connect to
Returns
-------
connectable : bool
Return True if no IOError (unable to connect) or URLError (bad url) was
raised
"""
if error_classes is None:
error_classes = _get_default_network_errors()
try:
with urlopen(url):
pass
except error_classes:
return False
else:
return True
@optional_args
def network(
t,
url="http://www.google.com",
raise_on_error=_RAISE_NETWORK_ERROR_DEFAULT,
check_before_test=False,
error_classes=None,
skip_errnos=_network_errno_vals,
_skip_on_messages=_network_error_messages,
):
"""
Label a test as requiring network connection and, if an error is
encountered, only raise if it does not find a network connection.
In comparison to ``network``, this assumes an added contract to your test:
you must assert that, under normal conditions, your test will ONLY fail if
it does not have network connectivity.
You can call this in 3 ways: as a standard decorator, with keyword
arguments, or with a positional argument that is the url to check.
Parameters
----------
t : callable
The test requiring network connectivity.
url : path
The url to test via ``pandas.io.common.urlopen`` to check
for connectivity. Defaults to 'http://www.google.com'.
raise_on_error : bool
If True, never catches errors.
check_before_test : bool
If True, checks connectivity before running the test case.
error_classes : tuple or Exception
error classes to ignore. If not in ``error_classes``, raises the error.
defaults to IOError. Be careful about changing the error classes here.
skip_errnos : iterable of int
Any exception that has .errno or .reason.erno set to one
of these values will be skipped with an appropriate
message.
_skip_on_messages: iterable of string
any exception e for which one of the strings is
a substring of str(e) will be skipped with an appropriate
message. Intended to suppress errors where an errno isn't available.
Notes
-----
* ``raise_on_error`` supercedes ``check_before_test``
Returns
-------
t : callable
The decorated test ``t``, with checks for connectivity errors.
Example
-------
Tests decorated with @network will fail if it's possible to make a network
connection to another URL (defaults to google.com)::
>>> from pandas._testing import network
>>> from pandas.io.common import urlopen
>>> @network
... def test_network():
... with urlopen("rabbit://bonanza.com"):
... pass
Traceback
...
URLError: <urlopen error unknown url type: rabit>
You can specify alternative URLs::
>>> @network("http://www.yahoo.com")
... def test_something_with_yahoo():
... raise IOError("Failure Message")
>>> test_something_with_yahoo()
Traceback (most recent call last):
...
IOError: Failure Message
If you set check_before_test, it will check the url first and not run the
test on failure::
>>> @network("failing://url.blaher", check_before_test=True)
... def test_something():
... print("I ran!")
... raise ValueError("Failure")
>>> test_something()
Traceback (most recent call last):
...
Errors not related to networking will always be raised.
"""
from pytest import skip
if error_classes is None:
error_classes = _get_default_network_errors()
t.network = True
@wraps(t)
def wrapper(*args, **kwargs):
if check_before_test and not raise_on_error:
if not can_connect(url, error_classes):
skip()
try:
return t(*args, **kwargs)
except Exception as err:
errno = getattr(err, "errno", None)
if not errno and hasattr(errno, "reason"):
errno = getattr(err.reason, "errno", None)
if errno in skip_errnos:
skip(f"Skipping test due to known errno and error {err}")
e_str = str(err)
if any(m.lower() in e_str.lower() for m in _skip_on_messages):
skip(
f"Skipping test because exception message is known and error {err}"
)
if not isinstance(err, error_classes):
raise
if raise_on_error or can_connect(url, error_classes):
raise
else:
skip(f"Skipping test due to lack of connectivity and error {err}")
return wrapper
with_connectivity_check = network
@contextmanager
def assert_produces_warning(
expected_warning=Warning,
filter_level="always",
check_stacklevel=True,
raise_on_extra_warnings=True,
):
"""
Context manager for running code expected to either raise a specific
warning, or not raise any warnings. Verifies that the code raises the
expected warning, and that it does not raise any other unexpected
warnings. It is basically a wrapper around ``warnings.catch_warnings``.
Parameters
----------
expected_warning : {Warning, False, None}, default Warning
The type of Exception raised. ``exception.Warning`` is the base
class for all warnings. To check that no warning is returned,
specify ``False`` or ``None``.
filter_level : str or None, default "always"
Specifies whether warnings are ignored, displayed, or turned
into errors.
Valid values are:
* "error" - turns matching warnings into exceptions
* "ignore" - discard the warning
* "always" - always emit a warning
* "default" - print the warning the first time it is generated
from each location
* "module" - print the warning the first time it is generated
from each module
* "once" - print the warning the first time it is generated
check_stacklevel : bool, default True
If True, displays the line that called the function containing
the warning to show were the function is called. Otherwise, the
line that implements the function is displayed.
raise_on_extra_warnings : bool, default True
Whether extra warnings not of the type `expected_warning` should
cause the test to fail.
Examples
--------
>>> import warnings
>>> with assert_produces_warning():
... warnings.warn(UserWarning())
...
>>> with assert_produces_warning(False):
... warnings.warn(RuntimeWarning())
...
Traceback (most recent call last):
...
AssertionError: Caused unexpected warning(s): ['RuntimeWarning'].
>>> with assert_produces_warning(UserWarning):
... warnings.warn(RuntimeWarning())
Traceback (most recent call last):
...
AssertionError: Did not see expected warning of class 'UserWarning'.
..warn:: This is *not* thread-safe.
"""
__tracebackhide__ = True
with warnings.catch_warnings(record=True) as w:
saw_warning = False
warnings.simplefilter(filter_level)
yield w
extra_warnings = []
for actual_warning in w:
if expected_warning and issubclass(
actual_warning.category, expected_warning
):
saw_warning = True
if check_stacklevel and issubclass(
actual_warning.category, (FutureWarning, DeprecationWarning)
):
from inspect import getframeinfo, stack
caller = getframeinfo(stack()[2][0])
msg = (
"Warning not set with correct stacklevel. "
f"File where warning is raised: {actual_warning.filename} != "
f"{caller.filename}. Warning message: {actual_warning.message}"
)
assert actual_warning.filename == caller.filename, msg
else:
extra_warnings.append(
(
actual_warning.category.__name__,
actual_warning.message,
actual_warning.filename,
actual_warning.lineno,
)
)
if expected_warning:
msg = (
f"Did not see expected warning of class "
f"{repr(expected_warning.__name__)}"
)
assert saw_warning, msg
if raise_on_extra_warnings and extra_warnings:
raise AssertionError(
f"Caused unexpected warning(s): {repr(extra_warnings)}"
)
class RNGContext:
"""
Context manager to set the numpy random number generator speed. Returns
to the original value upon exiting the context manager.
Parameters
----------
seed : int
Seed for numpy.random.seed
Examples
--------
with RNGContext(42):
np.random.randn()
"""
def __init__(self, seed):
self.seed = seed
def __enter__(self):
self.start_state = np.random.get_state()
np.random.seed(self.seed)
def __exit__(self, exc_type, exc_value, traceback):
np.random.set_state(self.start_state)
@contextmanager
def with_csv_dialect(name, **kwargs):
"""
Context manager to temporarily register a CSV dialect for parsing CSV.
Parameters
----------
name : str
The name of the dialect.
kwargs : mapping
The parameters for the dialect.
Raises
------
ValueError : the name of the dialect conflicts with a builtin one.
See Also
--------
csv : Python's CSV library.
"""
import csv
_BUILTIN_DIALECTS = {"excel", "excel-tab", "unix"}
if name in _BUILTIN_DIALECTS:
raise ValueError("Cannot override builtin dialect.")
csv.register_dialect(name, **kwargs)
yield
csv.unregister_dialect(name)
@contextmanager
def use_numexpr(use, min_elements=None):
from pandas.core.computation import expressions as expr
if min_elements is None:
min_elements = expr._MIN_ELEMENTS
olduse = expr._USE_NUMEXPR
oldmin = expr._MIN_ELEMENTS
expr.set_use_numexpr(use)
expr._MIN_ELEMENTS = min_elements
yield
expr._MIN_ELEMENTS = oldmin
expr.set_use_numexpr(olduse)
def test_parallel(num_threads=2, kwargs_list=None):
"""
Decorator to run the same function multiple times in parallel.
Parameters
----------
num_threads : int, optional
The number of times the function is run in parallel.
kwargs_list : list of dicts, optional
The list of kwargs to update original
function kwargs on different threads.
Notes
-----
This decorator does not pass the return value of the decorated function.
Original from scikit-image:
https://github.com/scikit-image/scikit-image/pull/1519
"""
assert num_threads > 0
has_kwargs_list = kwargs_list is not None
if has_kwargs_list:
assert len(kwargs_list) == num_threads
import threading
def wrapper(func):
@wraps(func)
def inner(*args, **kwargs):
if has_kwargs_list:
update_kwargs = lambda i: dict(kwargs, **kwargs_list[i])
else:
update_kwargs = lambda i: kwargs
threads = []
for i in range(num_threads):
updated_kwargs = update_kwargs(i)
thread = threading.Thread(target=func, args=args, kwargs=updated_kwargs)
threads.append(thread)
for thread in threads:
thread.start()
for thread in threads:
thread.join()
return inner
return wrapper
class SubclassedSeries(Series):
_metadata = ["testattr", "name"]
@property
def _constructor(self):
return SubclassedSeries
@property
def _constructor_expanddim(self):
return SubclassedDataFrame
class SubclassedDataFrame(DataFrame):
_metadata = ["testattr"]
@property
def _constructor(self):
return SubclassedDataFrame
@property
def _constructor_sliced(self):
return SubclassedSeries
class SubclassedCategorical(Categorical):
@property
def _constructor(self):
return SubclassedCategorical
@contextmanager
def set_timezone(tz: str):
"""
Context manager for temporarily setting a timezone.
Parameters
----------
tz : str
A string representing a valid timezone.
Examples
--------
>>> from datetime import datetime
>>> from dateutil.tz import tzlocal
>>> tzlocal().tzname(datetime.now())
'IST'
>>> with set_timezone('US/Eastern'):
... tzlocal().tzname(datetime.now())
...
'EDT'
"""
import os
import time
def setTZ(tz):
if tz is None:
try:
del os.environ["TZ"]
except KeyError:
pass
else:
os.environ["TZ"] = tz
time.tzset()
orig_tz = os.environ.get("TZ")
setTZ(tz)
try:
yield
finally:
setTZ(orig_tz)
def _make_skipna_wrapper(alternative, skipna_alternative=None):
"""
Create a function for calling on an array.
Parameters
----------
alternative : function
The function to be called on the array with no NaNs.
Only used when 'skipna_alternative' is None.
skipna_alternative : function
The function to be called on the original array
Returns
-------
function
"""
if skipna_alternative:
def skipna_wrapper(x):
return skipna_alternative(x.values)
else:
def skipna_wrapper(x):
nona = x.dropna()
if len(nona) == 0:
return np.nan
return alternative(nona)
return skipna_wrapper
def convert_rows_list_to_csv_str(rows_list: List[str]):
"""
Convert list of CSV rows to single CSV-formatted string for current OS.
This method is used for creating expected value of to_csv() method.
Parameters
----------
rows_list : List[str]
Each element represents the row of csv.
Returns
-------
str
Expected output of to_csv() in current OS.
"""
sep = os.linesep
expected = sep.join(rows_list) + sep
return expected
def external_error_raised(
expected_exception: Type[Exception],
) -> Callable[[Type[Exception], None], None]:
"""
Helper function to mark pytest.raises that have an external error message.
Parameters
----------
expected_exception : Exception
Expected error to raise.
Returns
-------
Callable
Regular `pytest.raises` function with `match` equal to `None`.
"""
import pytest
return pytest.raises(expected_exception, match=None)
import bz2
from collections import Counter
from contextlib import contextmanager
from datetime import datetime
from functools import wraps
import gzip
import os
from shutil import rmtree
import string
import tempfile
from typing import Any, Callable, List, Optional, Type, Union, cast
import warnings
import zipfile
import numpy as np
from numpy.random import rand, randn
from pandas._config.localization import ( # noqa:F401
can_set_locale,
get_locales,
set_locale,
)
import pandas._libs.testing as _testing
from pandas._typing import FilePathOrBuffer, FrameOrSeries
from pandas.compat import _get_lzma_file, _import_lzma
from pandas.core.dtypes.common import (
is_bool,
is_categorical_dtype,
is_datetime64_dtype,
is_datetime64tz_dtype,
is_extension_array_dtype,
is_interval_dtype,
is_number,
is_numeric_dtype,
is_period_dtype,
is_sequence,
is_timedelta64_dtype,
needs_i8_conversion,
)
from pandas.core.dtypes.missing import array_equivalent
import pandas as pd
from pandas import (
Categorical,
CategoricalIndex,
DataFrame,
DatetimeIndex,
Index,
IntervalIndex,
MultiIndex,
RangeIndex,
Series,
bdate_range,
)
from pandas.core.algorithms import take_1d
from pandas.core.arrays import (
DatetimeArray,
ExtensionArray,
IntervalArray,
PeriodArray,
TimedeltaArray,
period_array,
)
from pandas.io.common import urlopen
from pandas.io.formats.printing import pprint_thing
lzma = _import_lzma()
_N = 30
_K = 4
_RAISE_NETWORK_ERROR_DEFAULT = False
# set testing_mode
_testing_mode_warnings = (DeprecationWarning, ResourceWarning)
def set_testing_mode():
# set the testing mode filters
testing_mode = os.environ.get("PANDAS_TESTING_MODE", "None")
if "deprecate" in testing_mode:
warnings.simplefilter("always", _testing_mode_warnings)
def reset_testing_mode():
# reset the testing mode filters
testing_mode = os.environ.get("PANDAS_TESTING_MODE", "None")
if "deprecate" in testing_mode:
warnings.simplefilter("ignore", _testing_mode_warnings)
set_testing_mode()
def reset_display_options():
"""
Reset the display options for printing and representing objects.
"""
pd.reset_option("^display.", silent=True)
def round_trip_pickle(
obj: Any, path: Optional[FilePathOrBuffer] = None
) -> FrameOrSeries:
"""
Pickle an object and then read it again.
Parameters
----------
obj : any object
The object to pickle and then re-read.
path : str, path object or file-like object, default None
The path where the pickled object is written and then read.
Returns
-------
pandas object
The original object that was pickled and then re-read.
"""
_path = path
if _path is None:
_path = f"__{rands(10)}__.pickle"
with ensure_clean(_path) as temp_path:
pd.to_pickle(obj, temp_path)
return pd.read_pickle(temp_path)
def round_trip_pathlib(writer, reader, path: Optional[str] = None):
"""
Write an object to file specified by a pathlib.Path and read it back
Parameters
----------
writer : callable bound to pandas object
IO writing function (e.g. DataFrame.to_csv )
reader : callable
IO reading function (e.g. pd.read_csv )
path : str, default None
The path where the object is written and then read.
Returns
-------
pandas object
The original object that was serialized and then re-read.
"""
import pytest
Path = pytest.importorskip("pathlib").Path
if path is None:
path = "___pathlib___"
with ensure_clean(path) as path:
writer(Path(path))
obj = reader(Path(path))
return obj
def round_trip_localpath(writer, reader, path: Optional[str] = None):
"""
Write an object to file specified by a py.path LocalPath and read it back.
Parameters
----------
writer : callable bound to pandas object
IO writing function (e.g. DataFrame.to_csv )
reader : callable
IO reading function (e.g. pd.read_csv )
path : str, default None
The path where the object is written and then read.
Returns
-------
pandas object
The original object that was serialized and then re-read.
"""
import pytest
LocalPath = pytest.importorskip("py.path").local
if path is None:
path = "___localpath___"
with ensure_clean(path) as path:
writer(LocalPath(path))
obj = reader(LocalPath(path))
return obj
@contextmanager
def decompress_file(path, compression):
"""
Open a compressed file and return a file object.
Parameters
----------
path : str
The path where the file is read from.
compression : {'gzip', 'bz2', 'zip', 'xz', None}
Name of the decompression to use
Returns
-------
file object
"""
if compression is None:
f = open(path, "rb")
elif compression == "gzip":
f = gzip.open(path, "rb")
elif compression == "bz2":
f = bz2.BZ2File(path, "rb")
elif compression == "xz":
f = _get_lzma_file(lzma)(path, "rb")
elif compression == "zip":
zip_file = zipfile.ZipFile(path)
zip_names = zip_file.namelist()
if len(zip_names) == 1:
f = zip_file.open(zip_names.pop())
else:
raise ValueError(f"ZIP file {path} error. Only one file per ZIP.")
else:
raise ValueError(f"Unrecognized compression type: {compression}")
try:
yield f
finally:
f.close()
if compression == "zip":
zip_file.close()
def write_to_compressed(compression, path, data, dest="test"):
"""
Write data to a compressed file.
Parameters
----------
compression : {'gzip', 'bz2', 'zip', 'xz'}
The compression type to use.
path : str
The file path to write the data.
data : str
The data to write.
dest : str, default "test"
The destination file (for ZIP only)
Raises
------
ValueError : An invalid compression value was passed in.
"""
if compression == "zip":
import zipfile
compress_method = zipfile.ZipFile
elif compression == "gzip":
import gzip
compress_method = gzip.GzipFile
elif compression == "bz2":
import bz2
compress_method = bz2.BZ2File
elif compression == "xz":
compress_method = _get_lzma_file(lzma)
else:
raise ValueError(f"Unrecognized compression type: {compression}")
if compression == "zip":
mode = "w"
args = (dest, data)
method = "writestr"
else:
mode = "wb"
args = (data,)
method = "write"
with compress_method(path, mode=mode) as f:
getattr(f, method)(*args)
def assert_almost_equal(
left,
right,
check_dtype: Union[bool, str] = "equiv",
check_less_precise: Union[bool, int] = False,
**kwargs,
):
"""
Check that the left and right objects are approximately equal.
By approximately equal, we refer to objects that are numbers or that
contain numbers which may be equivalent to specific levels of precision.
Parameters
----------
left : object
right : object
check_dtype : bool or {'equiv'}, default 'equiv'
Check dtype if both a and b are the same type. If 'equiv' is passed in,
then `RangeIndex` and `Int64Index` are also considered equivalent
when doing type checking.
check_less_precise : bool or int, default False
Specify comparison precision. 5 digits (False) or 3 digits (True)
after decimal points are compared. If int, then specify the number
of digits to compare.
When comparing two numbers, if the first number has magnitude less
than 1e-5, we compare the two numbers directly and check whether
they are equivalent within the specified precision. Otherwise, we
compare the **ratio** of the second number to the first number and
check whether it is equivalent to 1 within the specified precision.
"""
if isinstance(left, pd.Index):
assert_index_equal(
left,
right,
check_exact=False,
exact=check_dtype,
check_less_precise=check_less_precise,
**kwargs,
)
elif isinstance(left, pd.Series):
assert_series_equal(
left,
right,
check_exact=False,
check_dtype=check_dtype,
check_less_precise=check_less_precise,
**kwargs,
)
elif isinstance(left, pd.DataFrame):
assert_frame_equal(
left,
right,
check_exact=False,
check_dtype=check_dtype,
check_less_precise=check_less_precise,
**kwargs,
)
else:
# Other sequences.
if check_dtype:
if is_number(left) and is_number(right):
# Do not compare numeric classes, like np.float64 and float.
pass
elif is_bool(left) and is_bool(right):
# Do not compare bool classes, like np.bool_ and bool.
pass
else:
if isinstance(left, np.ndarray) or isinstance(right, np.ndarray):
obj = "numpy array"
else:
obj = "Input"
assert_class_equal(left, right, obj=obj)
_testing.assert_almost_equal(
left,
right,
check_dtype=check_dtype,
check_less_precise=check_less_precise,
**kwargs,
)
def _check_isinstance(left, right, cls):
"""
Helper method for our assert_* methods that ensures that
the two objects being compared have the right type before
proceeding with the comparison.
Parameters
----------
left : The first object being compared.
right : The second object being compared.
cls : The class type to check against.
Raises
------
AssertionError : Either `left` or `right` is not an instance of `cls`.
"""
cls_name = cls.__name__
if not isinstance(left, cls):
raise AssertionError(
f"{cls_name} Expected type {cls}, found {type(left)} instead"
)
if not isinstance(right, cls):
raise AssertionError(
f"{cls_name} Expected type {cls}, found {type(right)} instead"
)
def assert_dict_equal(left, right, compare_keys: bool = True):
_check_isinstance(left, right, dict)
_testing.assert_dict_equal(left, right, compare_keys=compare_keys)
def randbool(size=(), p: float = 0.5):
return rand(*size) <= p
RANDS_CHARS = np.array(list(string.ascii_letters + string.digits), dtype=(np.str_, 1))
RANDU_CHARS = np.array(
list("".join(map(chr, range(1488, 1488 + 26))) + string.digits),
dtype=(np.unicode_, 1),
)
def rands_array(nchars, size, dtype="O"):
"""
Generate an array of byte strings.
"""
retval = (
np.random.choice(RANDS_CHARS, size=nchars * np.prod(size))
.view((np.str_, nchars))
.reshape(size)
)
return retval.astype(dtype)
def randu_array(nchars, size, dtype="O"):
"""
Generate an array of unicode strings.
"""
retval = (
np.random.choice(RANDU_CHARS, size=nchars * np.prod(size))
.view((np.unicode_, nchars))
.reshape(size)
)
return retval.astype(dtype)
def rands(nchars):
"""
Generate one random byte string.
See `rands_array` if you want to create an array of random strings.
"""
return "".join(np.random.choice(RANDS_CHARS, nchars))
def close(fignum=None):
from matplotlib.pyplot import get_fignums, close as _close
if fignum is None:
for fignum in get_fignums():
_close(fignum)
else:
_close(fignum)
# -----------------------------------------------------------------------------
# contextmanager to ensure the file cleanup
@contextmanager
def ensure_clean(filename=None, return_filelike=False, **kwargs):
"""
Gets a temporary path and agrees to remove on close.
Parameters
----------
filename : str (optional)
if None, creates a temporary file which is then removed when out of
scope. if passed, creates temporary file with filename as ending.
return_filelike : bool (default False)
if True, returns a file-like which is *always* cleaned. Necessary for
savefig and other functions which want to append extensions.
**kwargs
Additional keywords passed in for creating a temporary file.
:meth:`tempFile.TemporaryFile` is used when `return_filelike` is ``True``.
:meth:`tempfile.mkstemp` is used when `return_filelike` is ``False``.
Note that the `filename` parameter will be passed in as the `suffix`
argument to either function.
See Also
--------
tempfile.TemporaryFile
tempfile.mkstemp
"""
filename = filename or ""
fd = None
kwargs["suffix"] = filename
if return_filelike:
f = tempfile.TemporaryFile(**kwargs)
try:
yield f
finally:
f.close()
else:
# Don't generate tempfile if using a path with directory specified.
if len(os.path.dirname(filename)):
raise ValueError("Can't pass a qualified name to ensure_clean()")
try:
fd, filename = tempfile.mkstemp(**kwargs)
except UnicodeEncodeError:
import pytest
pytest.skip("no unicode file names on this system")
try:
yield filename
finally:
try:
os.close(fd)
except OSError:
print(f"Couldn't close file descriptor: {fd} (file: {filename})")
try:
if os.path.exists(filename):
os.remove(filename)
except OSError as e:
print(f"Exception on removing file: {e}")
@contextmanager
def ensure_clean_dir():
"""
Get a temporary directory path and agrees to remove on close.
Yields
------
Temporary directory path
"""
directory_name = tempfile.mkdtemp(suffix="")
try:
yield directory_name
finally:
try:
rmtree(directory_name)
except OSError:
pass
@contextmanager
def ensure_safe_environment_variables():
"""
Get a context manager to safely set environment variables
All changes will be undone on close, hence environment variables set
within this contextmanager will neither persist nor change global state.
"""
saved_environ = dict(os.environ)
try:
yield
finally:
os.environ.clear()
os.environ.update(saved_environ)
# -----------------------------------------------------------------------------
# Comparators
def equalContents(arr1, arr2) -> bool:
"""
Checks if the set of unique elements of arr1 and arr2 are equivalent.
"""
return frozenset(arr1) == frozenset(arr2)
def assert_index_equal(
left: Index,
right: Index,
exact: Union[bool, str] = "equiv",
check_names: bool = True,
check_less_precise: Union[bool, int] = False,
check_exact: bool = True,
check_categorical: bool = True,
obj: str = "Index",
) -> None:
"""
Check that left and right Index are equal.
Parameters
----------
left : Index
right : Index
exact : bool or {'equiv'}, default 'equiv'
Whether to check the Index class, dtype and inferred_type
are identical. If 'equiv', then RangeIndex can be substituted for
Int64Index as well.
check_names : bool, default True
Whether to check the names attribute.
check_less_precise : bool or int, default False
Specify comparison precision. Only used when check_exact is False.
5 digits (False) or 3 digits (True) after decimal points are compared.
If int, then specify the digits to compare.
check_exact : bool, default True
Whether to compare number exactly.
check_categorical : bool, default True
Whether to compare internal Categorical exactly.
obj : str, default 'Index'
Specify object name being compared, internally used to show appropriate
assertion message.
"""
__tracebackhide__ = True
def _check_types(l, r, obj="Index"):
if exact:
assert_class_equal(l, r, exact=exact, obj=obj)
# Skip exact dtype checking when `check_categorical` is False
if check_categorical:
assert_attr_equal("dtype", l, r, obj=obj)
# allow string-like to have different inferred_types
if l.inferred_type in ("string"):
assert r.inferred_type in ("string")
else:
assert_attr_equal("inferred_type", l, r, obj=obj)
def _get_ilevel_values(index, level):
# accept level number only
unique = index.levels[level]
level_codes = index.codes[level]
filled = take_1d(unique._values, level_codes, fill_value=unique._na_value)
values = unique._shallow_copy(filled, name=index.names[level])
return values
# instance validation
_check_isinstance(left, right, Index)
# class / dtype comparison
_check_types(left, right, obj=obj)
# level comparison
if left.nlevels != right.nlevels:
msg1 = f"{obj} levels are different"
msg2 = f"{left.nlevels}, {left}"
msg3 = f"{right.nlevels}, {right}"
raise_assert_detail(obj, msg1, msg2, msg3)
# length comparison
if len(left) != len(right):
msg1 = f"{obj} length are different"
msg2 = f"{len(left)}, {left}"
msg3 = f"{len(right)}, {right}"
raise_assert_detail(obj, msg1, msg2, msg3)
# MultiIndex special comparison for little-friendly error messages
if left.nlevels > 1:
left = cast(MultiIndex, left)
right = cast(MultiIndex, right)
for level in range(left.nlevels):
# cannot use get_level_values here because it can change dtype
llevel = _get_ilevel_values(left, level)
rlevel = _get_ilevel_values(right, level)
lobj = f"MultiIndex level [{level}]"
assert_index_equal(
llevel,
rlevel,
exact=exact,
check_names=check_names,
check_less_precise=check_less_precise,
check_exact=check_exact,
obj=lobj,
)
# get_level_values may change dtype
_check_types(left.levels[level], right.levels[level], obj=obj)
# skip exact index checking when `check_categorical` is False
if check_exact and check_categorical:
if not left.equals(right):
diff = np.sum((left.values != right.values).astype(int)) * 100.0 / len(left)
msg = f"{obj} values are different ({np.round(diff, 5)} %)"
raise_assert_detail(obj, msg, left, right)
else:
_testing.assert_almost_equal(
left.values,
right.values,
check_less_precise=check_less_precise,
check_dtype=exact,
obj=obj,
lobj=left,
robj=right,
)
# metadata comparison
if check_names:
assert_attr_equal("names", left, right, obj=obj)
if isinstance(left, pd.PeriodIndex) or isinstance(right, pd.PeriodIndex):
assert_attr_equal("freq", left, right, obj=obj)
if isinstance(left, pd.IntervalIndex) or isinstance(right, pd.IntervalIndex):
assert_interval_array_equal(left._values, right._values)
if check_categorical:
if is_categorical_dtype(left) or is_categorical_dtype(right):
assert_categorical_equal(left._values, right._values, obj=f"{obj} category")
def assert_class_equal(left, right, exact: Union[bool, str] = True, obj="Input"):
"""
Checks classes are equal.
"""
__tracebackhide__ = True
def repr_class(x):
if isinstance(x, Index):
# return Index as it is to include values in the error message
return x
return type(x).__name__
if exact == "equiv":
if type(left) != type(right):
# allow equivalence of Int64Index/RangeIndex
types = {type(left).__name__, type(right).__name__}
if len(types - {"Int64Index", "RangeIndex"}):
msg = f"{obj} classes are not equivalent"
raise_assert_detail(obj, msg, repr_class(left), repr_class(right))
elif exact:
if type(left) != type(right):
msg = f"{obj} classes are different"
raise_assert_detail(obj, msg, repr_class(left), repr_class(right))
def assert_attr_equal(attr: str, left, right, obj: str = "Attributes"):
"""
Check attributes are equal. Both objects must have attribute.
Parameters
----------
attr : str
Attribute name being compared.
left : object
right : object
obj : str, default 'Attributes'
Specify object name being compared, internally used to show appropriate
assertion message
"""
__tracebackhide__ = True
left_attr = getattr(left, attr)
right_attr = getattr(right, attr)
if left_attr is right_attr:
return True
elif (
is_number(left_attr)
and np.isnan(left_attr)
and is_number(right_attr)
and np.isnan(right_attr)
):
# np.nan
return True
try:
result = left_attr == right_attr
except TypeError:
# datetimetz on rhs may raise TypeError
result = False
if not isinstance(result, bool):
result = result.all()
if result:
return True
else:
msg = f'Attribute "{attr}" are different'
raise_assert_detail(obj, msg, left_attr, right_attr)
def assert_is_valid_plot_return_object(objs):
import matplotlib.pyplot as plt
if isinstance(objs, (pd.Series, np.ndarray)):
for el in objs.ravel():
msg = (
"one of 'objs' is not a matplotlib Axes instance, "
f"type encountered {repr(type(el).__name__)}"
)
assert isinstance(el, (plt.Axes, dict)), msg
else:
msg = (
"objs is neither an ndarray of Artist instances nor a single "
"ArtistArtist instance, tuple, or dict, 'objs' is a "
f"{repr(type(objs).__name__)}"
)
assert isinstance(objs, (plt.Artist, tuple, dict)), msg
def assert_is_sorted(seq):
"""Assert that the sequence is sorted."""
if isinstance(seq, (Index, Series)):
seq = seq.values
# sorting does not change precisions
assert_numpy_array_equal(seq, np.sort(np.array(seq)))
def assert_categorical_equal(
left, right, check_dtype=True, check_category_order=True, obj="Categorical"
):
"""
Test that Categoricals are equivalent.
Parameters
----------
left : Categorical
right : Categorical
check_dtype : bool, default True
Check that integer dtype of the codes are the same
check_category_order : bool, default True
Whether the order of the categories should be compared, which
implies identical integer codes. If False, only the resulting
values are compared. The ordered attribute is
checked regardless.
obj : str, default 'Categorical'
Specify object name being compared, internally used to show appropriate
assertion message
"""
_check_isinstance(left, right, Categorical)
if check_category_order:
assert_index_equal(left.categories, right.categories, obj=f"{obj}.categories")
assert_numpy_array_equal(
left.codes, right.codes, check_dtype=check_dtype, obj=f"{obj}.codes",
)
else:
try:
lc = left.categories.sort_values()
rc = right.categories.sort_values()
except TypeError:
# e.g. '<' not supported between instances of 'int' and 'str'
lc, rc = left.categories, right.categories
assert_index_equal(
lc, rc, obj=f"{obj}.categories",
)
assert_index_equal(
left.categories.take(left.codes),
right.categories.take(right.codes),
obj=f"{obj}.values",
)
assert_attr_equal("ordered", left, right, obj=obj)
def assert_interval_array_equal(left, right, exact="equiv", obj="IntervalArray"):
"""
Test that two IntervalArrays are equivalent.
Parameters
----------
left, right : IntervalArray
The IntervalArrays to compare.
exact : bool or {'equiv'}, default 'equiv'
Whether to check the Index class, dtype and inferred_type
are identical. If 'equiv', then RangeIndex can be substituted for
Int64Index as well.
obj : str, default 'IntervalArray'
Specify object name being compared, internally used to show appropriate
assertion message
"""
_check_isinstance(left, right, IntervalArray)
assert_index_equal(left.left, right.left, exact=exact, obj=f"{obj}.left")
assert_index_equal(left.right, right.right, exact=exact, obj=f"{obj}.left")
assert_attr_equal("closed", left, right, obj=obj)
def assert_period_array_equal(left, right, obj="PeriodArray"):
_check_isinstance(left, right, PeriodArray)
assert_numpy_array_equal(left._data, right._data, obj=f"{obj}._data")
assert_attr_equal("freq", left, right, obj=obj)
def assert_datetime_array_equal(left, right, obj="DatetimeArray"):
__tracebackhide__ = True
_check_isinstance(left, right, DatetimeArray)
assert_numpy_array_equal(left._data, right._data, obj=f"{obj}._data")
assert_attr_equal("freq", left, right, obj=obj)
assert_attr_equal("tz", left, right, obj=obj)
def assert_timedelta_array_equal(left, right, obj="TimedeltaArray"):
__tracebackhide__ = True
_check_isinstance(left, right, TimedeltaArray)
assert_numpy_array_equal(left._data, right._data, obj=f"{obj}._data")
assert_attr_equal("freq", left, right, obj=obj)
def raise_assert_detail(obj, message, left, right, diff=None):
__tracebackhide__ = True
if isinstance(left, np.ndarray):
left = pprint_thing(left)
elif is_categorical_dtype(left):
left = repr(left)
if isinstance(right, np.ndarray):
right = pprint_thing(right)
elif is_categorical_dtype(right):
right = repr(right)
msg = f"""{obj} are different
{message}
[left]: {left}
[right]: {right}"""
if diff is not None:
msg += f"\n[diff]: {diff}"
raise AssertionError(msg)
def assert_numpy_array_equal(
left,
right,
strict_nan=False,
check_dtype=True,
err_msg=None,
check_same=None,
obj="numpy array",
):
"""
Check that 'np.ndarray' is equivalent.
Parameters
----------
left, right : numpy.ndarray or iterable
The two arrays to be compared.
strict_nan : bool, default False
If True, consider NaN and None to be different.
check_dtype : bool, default True
Check dtype if both a and b are np.ndarray.
err_msg : str, default None
If provided, used as assertion message.
check_same : None|'copy'|'same', default None
Ensure left and right refer/do not refer to the same memory area.
obj : str, default 'numpy array'
Specify object name being compared, internally used to show appropriate
assertion message.
"""
__tracebackhide__ = True
# instance validation
# Show a detailed error message when classes are different
assert_class_equal(left, right, obj=obj)
# both classes must be an np.ndarray
_check_isinstance(left, right, np.ndarray)
def _get_base(obj):
return obj.base if getattr(obj, "base", None) is not None else obj
left_base = _get_base(left)
right_base = _get_base(right)
if check_same == "same":
if left_base is not right_base:
raise AssertionError(f"{repr(left_base)} is not {repr(right_base)}")
elif check_same == "copy":
if left_base is right_base:
raise AssertionError(f"{repr(left_base)} is {repr(right_base)}")
def _raise(left, right, err_msg):
if err_msg is None:
if left.shape != right.shape:
raise_assert_detail(
obj, f"{obj} shapes are different", left.shape, right.shape,
)
diff = 0
for l, r in zip(left, right):
# count up differences
if not array_equivalent(l, r, strict_nan=strict_nan):
diff += 1
diff = diff * 100.0 / left.size
msg = f"{obj} values are different ({np.round(diff, 5)} %)"
raise_assert_detail(obj, msg, left, right)
raise AssertionError(err_msg)
# compare shape and values
if not array_equivalent(left, right, strict_nan=strict_nan):
_raise(left, right, err_msg)
if check_dtype:
if isinstance(left, np.ndarray) and isinstance(right, np.ndarray):
assert_attr_equal("dtype", left, right, obj=obj)
def assert_extension_array_equal(
left, right, check_dtype=True, check_less_precise=False, check_exact=False
):
"""
Check that left and right ExtensionArrays are equal.
Parameters
----------
left, right : ExtensionArray
The two arrays to compare.
check_dtype : bool, default True
Whether to check if the ExtensionArray dtypes are identical.
check_less_precise : bool or int, default False
Specify comparison precision. Only used when check_exact is False.
5 digits (False) or 3 digits (True) after decimal points are compared.
If int, then specify the digits to compare.
check_exact : bool, default False
Whether to compare number exactly.
Notes
-----
Missing values are checked separately from valid values.
A mask of missing values is computed for each and checked to match.
The remaining all-valid values are cast to object dtype and checked.
"""
assert isinstance(left, ExtensionArray), "left is not an ExtensionArray"
assert isinstance(right, ExtensionArray), "right is not an ExtensionArray"
if check_dtype:
assert_attr_equal("dtype", left, right, obj="ExtensionArray")
if hasattr(left, "asi8") and type(right) == type(left):
# Avoid slow object-dtype comparisons
# np.asarray for case where we have a np.MaskedArray
assert_numpy_array_equal(np.asarray(left.asi8), np.asarray(right.asi8))
return
left_na = np.asarray(left.isna())
right_na = np.asarray(right.isna())
assert_numpy_array_equal(left_na, right_na, obj="ExtensionArray NA mask")
left_valid = np.asarray(left[~left_na].astype(object))
right_valid = np.asarray(right[~right_na].astype(object))
if check_exact:
assert_numpy_array_equal(left_valid, right_valid, obj="ExtensionArray")
else:
_testing.assert_almost_equal(
left_valid,
right_valid,
check_dtype=check_dtype,
check_less_precise=check_less_precise,
obj="ExtensionArray",
)
# This could be refactored to use the NDFrame.equals method
def assert_series_equal(
left,
right,
check_dtype=True,
check_index_type="equiv",
check_series_type=True,
check_less_precise=False,
check_names=True,
check_exact=False,
check_datetimelike_compat=False,
check_categorical=True,
check_category_order=True,
obj="Series",
):
"""
Check that left and right Series are equal.
Parameters
----------
left : Series
right : Series
check_dtype : bool, default True
Whether to check the Series dtype is identical.
check_index_type : bool or {'equiv'}, default 'equiv'
Whether to check the Index class, dtype and inferred_type
are identical.
check_series_type : bool, default True
Whether to check the Series class is identical.
check_less_precise : bool or int, default False
Specify comparison precision. Only used when check_exact is False.
5 digits (False) or 3 digits (True) after decimal points are compared.
If int, then specify the digits to compare.
When comparing two numbers, if the first number has magnitude less
than 1e-5, we compare the two numbers directly and check whether
they are equivalent within the specified precision. Otherwise, we
compare the **ratio** of the second number to the first number and
check whether it is equivalent to 1 within the specified precision.
check_names : bool, default True
Whether to check the Series and Index names attribute.
check_exact : bool, default False
Whether to compare number exactly.
check_datetimelike_compat : bool, default False
Compare datetime-like which is comparable ignoring dtype.
check_categorical : bool, default True
Whether to compare internal Categorical exactly.
check_category_order : bool, default True
Whether to compare category order of internal Categoricals.
.. versionadded:: 1.0.2
obj : str, default 'Series'
Specify object name being compared, internally used to show appropriate
assertion message.
"""
__tracebackhide__ = True
# instance validation
_check_isinstance(left, right, Series)
if check_series_type:
assert_class_equal(left, right, obj=obj)
# length comparison
if len(left) != len(right):
msg1 = f"{len(left)}, {left.index}"
msg2 = f"{len(right)}, {right.index}"
raise_assert_detail(obj, "Series length are different", msg1, msg2)
# index comparison
assert_index_equal(
left.index,
right.index,
exact=check_index_type,
check_names=check_names,
check_less_precise=check_less_precise,
check_exact=check_exact,
check_categorical=check_categorical,
obj=f"{obj}.index",
)
if check_dtype:
# We want to skip exact dtype checking when `check_categorical`
# is False. We'll still raise if only one is a `Categorical`,
# regardless of `check_categorical`
if (
is_categorical_dtype(left.dtype)
and is_categorical_dtype(right.dtype)
and not check_categorical
):
pass
else:
assert_attr_equal("dtype", left, right, obj=f"Attributes of {obj}")
if check_exact:
if not is_numeric_dtype(left.dtype):
raise AssertionError("check_exact may only be used with numeric Series")
assert_numpy_array_equal(
left._values, right._values, check_dtype=check_dtype, obj=str(obj)
)
elif check_datetimelike_compat and (
needs_i8_conversion(left.dtype) or needs_i8_conversion(right.dtype)
):
# we want to check only if we have compat dtypes
# e.g. integer and M|m are NOT compat, but we can simply check
# the values in that case
# datetimelike may have different objects (e.g. datetime.datetime
# vs Timestamp) but will compare equal
if not Index(left._values).equals(Index(right._values)):
msg = (
f"[datetimelike_compat=True] {left._values} "
f"is not equal to {right._values}."
)
raise AssertionError(msg)
elif is_interval_dtype(left.dtype) and is_interval_dtype(right.dtype):
assert_interval_array_equal(left.array, right.array)
elif is_categorical_dtype(left.dtype) or is_categorical_dtype(right.dtype):
_testing.assert_almost_equal(
left._values,
right._values,
check_less_precise=check_less_precise,
check_dtype=check_dtype,
obj=str(obj),
)
elif is_extension_array_dtype(left.dtype) and is_extension_array_dtype(right.dtype):
assert_extension_array_equal(left._values, right._values)
elif needs_i8_conversion(left.dtype) or needs_i8_conversion(right.dtype):
# DatetimeArray or TimedeltaArray
assert_extension_array_equal(left._values, right._values)
else:
_testing.assert_almost_equal(
left._values,
right._values,
check_less_precise=check_less_precise,
check_dtype=check_dtype,
obj=str(obj),
)
# metadata comparison
if check_names:
assert_attr_equal("name", left, right, obj=obj)
if check_categorical:
if is_categorical_dtype(left) or is_categorical_dtype(right):
assert_categorical_equal(
left._values,
right._values,
obj=f"{obj} category",
check_category_order=check_category_order,
)
# This could be refactored to use the NDFrame.equals method
def assert_frame_equal(
left,
right,
check_dtype=True,
check_index_type="equiv",
check_column_type="equiv",
check_frame_type=True,
check_less_precise=False,
check_names=True,
by_blocks=False,
check_exact=False,
check_datetimelike_compat=False,
check_categorical=True,
check_like=False,
obj="DataFrame",
):
"""
Check that left and right DataFrame are equal.
This function is intended to compare two DataFrames and output any
differences. Is is mostly intended for use in unit tests.
Additional parameters allow varying the strictness of the
equality checks performed.
Parameters
----------
left : DataFrame
First DataFrame to compare.
right : DataFrame
Second DataFrame to compare.
check_dtype : bool, default True
Whether to check the DataFrame dtype is identical.
check_index_type : bool or {'equiv'}, default 'equiv'
Whether to check the Index class, dtype and inferred_type
are identical.
check_column_type : bool or {'equiv'}, default 'equiv'
Whether to check the columns class, dtype and inferred_type
are identical. Is passed as the ``exact`` argument of
:func:`assert_index_equal`.
check_frame_type : bool, default True
Whether to check the DataFrame class is identical.
check_less_precise : bool or int, default False
Specify comparison precision. Only used when check_exact is False.
5 digits (False) or 3 digits (True) after decimal points are compared.
If int, then specify the digits to compare.
When comparing two numbers, if the first number has magnitude less
than 1e-5, we compare the two numbers directly and check whether
they are equivalent within the specified precision. Otherwise, we
compare the **ratio** of the second number to the first number and
check whether it is equivalent to 1 within the specified precision.
check_names : bool, default True
Whether to check that the `names` attribute for both the `index`
and `column` attributes of the DataFrame is identical.
by_blocks : bool, default False
Specify how to compare internal data. If False, compare by columns.
If True, compare by blocks.
check_exact : bool, default False
Whether to compare number exactly.
check_datetimelike_compat : bool, default False
Compare datetime-like which is comparable ignoring dtype.
check_categorical : bool, default True
Whether to compare internal Categorical exactly.
check_like : bool, default False
If True, ignore the order of index & columns.
Note: index labels must match their respective rows
(same as in columns) - same labels must be with the same data.
obj : str, default 'DataFrame'
Specify object name being compared, internally used to show appropriate
assertion message.
See Also
--------
assert_series_equal : Equivalent method for asserting Series equality.
DataFrame.equals : Check DataFrame equality.
Examples
--------
This example shows comparing two DataFrames that are equal
but with columns of differing dtypes.
>>> from pandas._testing import assert_frame_equal
>>> df1 = pd.DataFrame({'a': [1, 2], 'b': [3, 4]})
>>> df2 = pd.DataFrame({'a': [1, 2], 'b': [3.0, 4.0]})
df1 equals itself.
>>> assert_frame_equal(df1, df1)
df1 differs from df2 as column 'b' is of a different type.
>>> assert_frame_equal(df1, df2)
Traceback (most recent call last):
...
AssertionError: Attributes of DataFrame.iloc[:, 1] (column name="b") are different
Attribute "dtype" are different
[left]: int64
[right]: float64
Ignore differing dtypes in columns with check_dtype.
>>> assert_frame_equal(df1, df2, check_dtype=False)
"""
__tracebackhide__ = True
# instance validation
_check_isinstance(left, right, DataFrame)
if check_frame_type:
assert isinstance(left, type(right))
# assert_class_equal(left, right, obj=obj)
# shape comparison
if left.shape != right.shape:
raise_assert_detail(
obj, f"{obj} shape mismatch", f"{repr(left.shape)}", f"{repr(right.shape)}",
)
if check_like:
left, right = left.reindex_like(right), right
# index comparison
assert_index_equal(
left.index,
right.index,
exact=check_index_type,
check_names=check_names,
check_less_precise=check_less_precise,
check_exact=check_exact,
check_categorical=check_categorical,
obj=f"{obj}.index",
)
# column comparison
assert_index_equal(
left.columns,
right.columns,
exact=check_column_type,
check_names=check_names,
check_less_precise=check_less_precise,
check_exact=check_exact,
check_categorical=check_categorical,
obj=f"{obj}.columns",
)
# compare by blocks
if by_blocks:
rblocks = right._to_dict_of_blocks()
lblocks = left._to_dict_of_blocks()
for dtype in list(set(list(lblocks.keys()) + list(rblocks.keys()))):
assert dtype in lblocks
assert dtype in rblocks
assert_frame_equal(
lblocks[dtype], rblocks[dtype], check_dtype=check_dtype, obj=obj
)
# compare by columns
else:
for i, col in enumerate(left.columns):
assert col in right
lcol = left.iloc[:, i]
rcol = right.iloc[:, i]
assert_series_equal(
lcol,
rcol,
check_dtype=check_dtype,
check_index_type=check_index_type,
check_less_precise=check_less_precise,
check_exact=check_exact,
check_names=check_names,
check_datetimelike_compat=check_datetimelike_compat,
check_categorical=check_categorical,
obj=f'{obj}.iloc[:, {i}] (column name="{col}")',
)
def assert_equal(left, right, **kwargs):
"""
Wrapper for tm.assert_*_equal to dispatch to the appropriate test function.
Parameters
----------
left, right : Index, Series, DataFrame, ExtensionArray, or np.ndarray
The two items to be compared.
**kwargs
All keyword arguments are passed through to the underlying assert method.
"""
__tracebackhide__ = True
if isinstance(left, pd.Index):
assert_index_equal(left, right, **kwargs)
elif isinstance(left, pd.Series):
assert_series_equal(left, right, **kwargs)
elif isinstance(left, pd.DataFrame):
assert_frame_equal(left, right, **kwargs)
elif isinstance(left, IntervalArray):
assert_interval_array_equal(left, right, **kwargs)
elif isinstance(left, PeriodArray):
assert_period_array_equal(left, right, **kwargs)
elif isinstance(left, DatetimeArray):
assert_datetime_array_equal(left, right, **kwargs)
elif isinstance(left, TimedeltaArray):
assert_timedelta_array_equal(left, right, **kwargs)
elif isinstance(left, ExtensionArray):
assert_extension_array_equal(left, right, **kwargs)
elif isinstance(left, np.ndarray):
assert_numpy_array_equal(left, right, **kwargs)
elif isinstance(left, str):
assert kwargs == {}
assert left == right
else:
raise NotImplementedError(type(left))
def box_expected(expected, box_cls, transpose=True):
"""
Helper function to wrap the expected output of a test in a given box_class.
Parameters
----------
expected : np.ndarray, Index, Series
box_cls : {Index, Series, DataFrame}
Returns
-------
subclass of box_cls
"""
if box_cls is pd.Index:
expected = pd.Index(expected)
elif box_cls is pd.Series:
expected = pd.Series(expected)
elif box_cls is pd.DataFrame:
expected = pd.Series(expected).to_frame()
if transpose:
# for vector operations, we we need a DataFrame to be a single-row,
# not a single-column, in order to operate against non-DataFrame
# vectors of the same length.
expected = expected.T
elif box_cls is PeriodArray:
# the PeriodArray constructor is not as flexible as period_array
expected = period_array(expected)
elif box_cls is DatetimeArray:
expected = DatetimeArray(expected)
elif box_cls is TimedeltaArray:
expected = TimedeltaArray(expected)
elif box_cls is np.ndarray:
expected = np.array(expected)
elif box_cls is to_array:
expected = to_array(expected)
else:
raise NotImplementedError(box_cls)
return expected
def to_array(obj):
# temporary implementation until we get pd.array in place
if is_period_dtype(obj):
return period_array(obj)
elif is_datetime64_dtype(obj) or is_datetime64tz_dtype(obj):
return DatetimeArray._from_sequence(obj)
elif is_timedelta64_dtype(obj):
return TimedeltaArray._from_sequence(obj)
else:
return np.array(obj)
# -----------------------------------------------------------------------------
# Sparse
def assert_sp_array_equal(left, right):
"""
Check that the left and right SparseArray are equal.
Parameters
----------
left : SparseArray
right : SparseArray
"""
_check_isinstance(left, right, pd.arrays.SparseArray)
assert_numpy_array_equal(left.sp_values, right.sp_values)
# SparseIndex comparison
assert isinstance(left.sp_index, pd._libs.sparse.SparseIndex)
assert isinstance(right.sp_index, pd._libs.sparse.SparseIndex)
left_index = left.sp_index
right_index = right.sp_index
if not left_index.equals(right_index):
raise_assert_detail(
"SparseArray.index", "index are not equal", left_index, right_index
)
else:
# Just ensure a
pass
assert_attr_equal("fill_value", left, right)
assert_attr_equal("dtype", left, right)
assert_numpy_array_equal(left.to_dense(), right.to_dense())
# -----------------------------------------------------------------------------
# Others
def assert_contains_all(iterable, dic):
for k in iterable:
assert k in dic, f"Did not contain item: {repr(k)}"
def assert_copy(iter1, iter2, **eql_kwargs):
"""
iter1, iter2: iterables that produce elements
comparable with assert_almost_equal
Checks that the elements are equal, but not
the same object. (Does not check that items
in sequences are also not the same object)
"""
for elem1, elem2 in zip(iter1, iter2):
assert_almost_equal(elem1, elem2, **eql_kwargs)
msg = (
f"Expected object {repr(type(elem1))} and object {repr(type(elem2))} to be "
"different objects, but they were the same object."
)
assert elem1 is not elem2, msg
def getCols(k):
return string.ascii_uppercase[:k]
# make index
def makeStringIndex(k=10, name=None):
return Index(rands_array(nchars=10, size=k), name=name)
def makeUnicodeIndex(k=10, name=None):
return Index(randu_array(nchars=10, size=k), name=name)
def makeCategoricalIndex(k=10, n=3, name=None, **kwargs):
""" make a length k index or n categories """
x = rands_array(nchars=4, size=n)
return CategoricalIndex(
Categorical.from_codes(np.arange(k) % n, categories=x), name=name, **kwargs
)
def makeIntervalIndex(k=10, name=None, **kwargs):
""" make a length k IntervalIndex """
x = np.linspace(0, 100, num=(k + 1))
return IntervalIndex.from_breaks(x, name=name, **kwargs)
def makeBoolIndex(k=10, name=None):
if k == 1:
return Index([True], name=name)
elif k == 2:
return Index([False, True], name=name)
return Index([False, True] + [False] * (k - 2), name=name)
def makeIntIndex(k=10, name=None):
return Index(list(range(k)), name=name)
def makeUIntIndex(k=10, name=None):
return Index([2 ** 63 + i for i in range(k)], name=name)
def makeRangeIndex(k=10, name=None, **kwargs):
return RangeIndex(0, k, 1, name=name, **kwargs)
def makeFloatIndex(k=10, name=None):
values = sorted(np.random.random_sample(k)) - np.random.random_sample(1)
return Index(values * (10 ** np.random.randint(0, 9)), name=name)
def makeDateIndex(k=10, freq="B", name=None, **kwargs):
dt = datetime(2000, 1, 1)
dr = bdate_range(dt, periods=k, freq=freq, name=name)
return DatetimeIndex(dr, name=name, **kwargs)
def makeTimedeltaIndex(k=10, freq="D", name=None, **kwargs):
return pd.timedelta_range(start="1 day", periods=k, freq=freq, name=name, **kwargs)
def makePeriodIndex(k=10, name=None, **kwargs):
dt = datetime(2000, 1, 1)
dr = pd.period_range(start=dt, periods=k, freq="B", name=name, **kwargs)
return dr
def makeMultiIndex(k=10, names=None, **kwargs):
return MultiIndex.from_product((("foo", "bar"), (1, 2)), names=names, **kwargs)
_names = [
"Alice",
"Bob",
"Charlie",
"Dan",
"Edith",
"Frank",
"George",
"Hannah",
"Ingrid",
"Jerry",
"Kevin",
"Laura",
"Michael",
"Norbert",
"Oliver",
"Patricia",
"Quinn",
"Ray",
"Sarah",
"Tim",
"Ursula",
"Victor",
"Wendy",
"Xavier",
"Yvonne",
"Zelda",
]
def _make_timeseries(start="2000-01-01", end="2000-12-31", freq="1D", seed=None):
"""
Make a DataFrame with a DatetimeIndex
Parameters
----------
start : str or Timestamp, default "2000-01-01"
The start of the index. Passed to date_range with `freq`.
end : str or Timestamp, default "2000-12-31"
The end of the index. Passed to date_range with `freq`.
freq : str or Freq
The frequency to use for the DatetimeIndex
seed : int, optional
The random state seed.
* name : object dtype with string names
* id : int dtype with
* x, y : float dtype
Examples
--------
>>> _make_timeseries()
id name x y
timestamp
2000-01-01 982 Frank 0.031261 0.986727
2000-01-02 1025 Edith -0.086358 -0.032920
2000-01-03 982 Edith 0.473177 0.298654
2000-01-04 1009 Sarah 0.534344 -0.750377
2000-01-05 963 Zelda -0.271573 0.054424
... ... ... ... ...
2000-12-27 980 Ingrid -0.132333 -0.422195
2000-12-28 972 Frank -0.376007 -0.298687
2000-12-29 1009 Ursula -0.865047 -0.503133
2000-12-30 1000 Hannah -0.063757 -0.507336
2000-12-31 972 Tim -0.869120 0.531685
"""
index = pd.date_range(start=start, end=end, freq=freq, name="timestamp")
n = len(index)
state = np.random.RandomState(seed)
columns = {
"name": state.choice(_names, size=n),
"id": state.poisson(1000, size=n),
"x": state.rand(n) * 2 - 1,
"y": state.rand(n) * 2 - 1,
}
df = pd.DataFrame(columns, index=index, columns=sorted(columns))
if df.index[-1] == end:
df = df.iloc[:-1]
return df
def all_index_generator(k=10):
"""
Generator which can be iterated over to get instances of all the various
index classes.
Parameters
----------
k: length of each of the index instances
"""
all_make_index_funcs = [
makeIntIndex,
makeFloatIndex,
makeStringIndex,
makeUnicodeIndex,
makeDateIndex,
makePeriodIndex,
makeTimedeltaIndex,
makeBoolIndex,
makeRangeIndex,
makeIntervalIndex,
makeCategoricalIndex,
]
for make_index_func in all_make_index_funcs:
yield make_index_func(k=k)
def index_subclass_makers_generator():
make_index_funcs = [
makeDateIndex,
makePeriodIndex,
makeTimedeltaIndex,
makeRangeIndex,
makeIntervalIndex,
makeCategoricalIndex,
makeMultiIndex,
]
for make_index_func in make_index_funcs:
yield make_index_func
def all_timeseries_index_generator(k=10):
"""
Generator which can be iterated over to get instances of all the classes
which represent time-series.
Parameters
----------
k: length of each of the index instances
"""
make_index_funcs = [makeDateIndex, makePeriodIndex, makeTimedeltaIndex]
for make_index_func in make_index_funcs:
yield make_index_func(k=k)
# make series
def makeFloatSeries(name=None):
index = makeStringIndex(_N)
return Series(randn(_N), index=index, name=name)
def makeStringSeries(name=None):
index = makeStringIndex(_N)
return Series(randn(_N), index=index, name=name)
def makeObjectSeries(name=None):
data = makeStringIndex(_N)
data = Index(data, dtype=object)
index = makeStringIndex(_N)
return Series(data, index=index, name=name)
def getSeriesData():
index = makeStringIndex(_N)
return {c: Series(randn(_N), index=index) for c in getCols(_K)}
def makeTimeSeries(nper=None, freq="B", name=None):
if nper is None:
nper = _N
return Series(randn(nper), index=makeDateIndex(nper, freq=freq), name=name)
def makePeriodSeries(nper=None, name=None):
if nper is None:
nper = _N
return Series(randn(nper), index=makePeriodIndex(nper), name=name)
def getTimeSeriesData(nper=None, freq="B"):
return {c: makeTimeSeries(nper, freq) for c in getCols(_K)}
def getPeriodData(nper=None):
return {c: makePeriodSeries(nper) for c in getCols(_K)}
# make frame
def makeTimeDataFrame(nper=None, freq="B"):
data = getTimeSeriesData(nper, freq)
return DataFrame(data)
def makeDataFrame():
data = getSeriesData()
return DataFrame(data)
def getMixedTypeDict():
index = Index(["a", "b", "c", "d", "e"])
data = {
"A": [0.0, 1.0, 2.0, 3.0, 4.0],
"B": [0.0, 1.0, 0.0, 1.0, 0.0],
"C": ["foo1", "foo2", "foo3", "foo4", "foo5"],
"D": bdate_range("1/1/2009", periods=5),
}
return index, data
def makeMixedDataFrame():
return DataFrame(getMixedTypeDict()[1])
def makePeriodFrame(nper=None):
data = getPeriodData(nper)
return DataFrame(data)
def makeCustomIndex(
nentries, nlevels, prefix="#", names=False, ndupe_l=None, idx_type=None
):
"""
Create an index/multindex with given dimensions, levels, names, etc'
nentries - number of entries in index
nlevels - number of levels (> 1 produces multindex)
prefix - a string prefix for labels
names - (Optional), bool or list of strings. if True will use default
names, if false will use no names, if a list is given, the name of
each level in the index will be taken from the list.
ndupe_l - (Optional), list of ints, the number of rows for which the
label will repeated at the corresponding level, you can specify just
the first few, the rest will use the default ndupe_l of 1.
len(ndupe_l) <= nlevels.
idx_type - "i"/"f"/"s"/"u"/"dt"/"p"/"td".
If idx_type is not None, `idx_nlevels` must be 1.
"i"/"f" creates an integer/float index,
"s"/"u" creates a string/unicode index
"dt" create a datetime index.
"td" create a datetime index.
if unspecified, string labels will be generated.
"""
if ndupe_l is None:
ndupe_l = [1] * nlevels
assert is_sequence(ndupe_l) and len(ndupe_l) <= nlevels
assert names is None or names is False or names is True or len(names) is nlevels
assert idx_type is None or (
idx_type in ("i", "f", "s", "u", "dt", "p", "td") and nlevels == 1
)
if names is True:
# build default names
names = [prefix + str(i) for i in range(nlevels)]
if names is False:
# pass None to index constructor for no name
names = None
# make singleton case uniform
if isinstance(names, str) and nlevels == 1:
names = [names]
# specific 1D index type requested?
idx_func = dict(
i=makeIntIndex,
f=makeFloatIndex,
s=makeStringIndex,
u=makeUnicodeIndex,
dt=makeDateIndex,
td=makeTimedeltaIndex,
p=makePeriodIndex,
).get(idx_type)
if idx_func:
idx = idx_func(nentries)
# but we need to fill in the name
if names:
idx.name = names[0]
return idx
elif idx_type is not None:
raise ValueError(
f"{repr(idx_type)} is not a legal value for `idx_type`, "
"use 'i'/'f'/'s'/'u'/'dt'/'p'/'td'."
)
if len(ndupe_l) < nlevels:
ndupe_l.extend([1] * (nlevels - len(ndupe_l)))
assert len(ndupe_l) == nlevels
assert all(x > 0 for x in ndupe_l)
tuples = []
for i in range(nlevels):
def keyfunc(x):
import re
numeric_tuple = re.sub(r"[^\d_]_?", "", x).split("_")
return [int(num) for num in numeric_tuple]
# build a list of lists to create the index from
div_factor = nentries // ndupe_l[i] + 1
cnt = Counter()
for j in range(div_factor):
label = f"{prefix}_l{i}_g{j}"
cnt[label] = ndupe_l[i]
# cute Counter trick
result = sorted(cnt.elements(), key=keyfunc)[:nentries]
tuples.append(result)
tuples = list(zip(*tuples))
# convert tuples to index
if nentries == 1:
# we have a single level of tuples, i.e. a regular Index
index = Index(tuples[0], name=names[0])
elif nlevels == 1:
name = None if names is None else names[0]
index = Index((x[0] for x in tuples), name=name)
else:
index = MultiIndex.from_tuples(tuples, names=names)
return index
def makeCustomDataframe(
nrows,
ncols,
c_idx_names=True,
r_idx_names=True,
c_idx_nlevels=1,
r_idx_nlevels=1,
data_gen_f=None,
c_ndupe_l=None,
r_ndupe_l=None,
dtype=None,
c_idx_type=None,
r_idx_type=None,
):
"""
Create a DataFrame using supplied parameters.
Parameters
----------
nrows, ncols - number of data rows/cols
c_idx_names, idx_names - False/True/list of strings, yields No names ,
default names or uses the provided names for the levels of the
corresponding index. You can provide a single string when
c_idx_nlevels ==1.
c_idx_nlevels - number of levels in columns index. > 1 will yield MultiIndex
r_idx_nlevels - number of levels in rows index. > 1 will yield MultiIndex
data_gen_f - a function f(row,col) which return the data value
at that position, the default generator used yields values of the form
"RxCy" based on position.
c_ndupe_l, r_ndupe_l - list of integers, determines the number
of duplicates for each label at a given level of the corresponding
index. The default `None` value produces a multiplicity of 1 across
all levels, i.e. a unique index. Will accept a partial list of length
N < idx_nlevels, for just the first N levels. If ndupe doesn't divide
nrows/ncol, the last label might have lower multiplicity.
dtype - passed to the DataFrame constructor as is, in case you wish to
have more control in conjunction with a custom `data_gen_f`
r_idx_type, c_idx_type - "i"/"f"/"s"/"u"/"dt"/"td".
If idx_type is not None, `idx_nlevels` must be 1.
"i"/"f" creates an integer/float index,
"s"/"u" creates a string/unicode index
"dt" create a datetime index.
"td" create a timedelta index.
if unspecified, string labels will be generated.
Examples
--------
# 5 row, 3 columns, default names on both, single index on both axis
>> makeCustomDataframe(5,3)
# make the data a random int between 1 and 100
>> mkdf(5,3,data_gen_f=lambda r,c:randint(1,100))
# 2-level multiindex on rows with each label duplicated
# twice on first level, default names on both axis, single
# index on both axis
>> a=makeCustomDataframe(5,3,r_idx_nlevels=2,r_ndupe_l=[2])
# DatetimeIndex on row, index with unicode labels on columns
# no names on either axis
>> a=makeCustomDataframe(5,3,c_idx_names=False,r_idx_names=False,
r_idx_type="dt",c_idx_type="u")
# 4-level multindex on rows with names provided, 2-level multindex
# on columns with default labels and default names.
>> a=makeCustomDataframe(5,3,r_idx_nlevels=4,
r_idx_names=["FEE","FI","FO","FAM"],
c_idx_nlevels=2)
>> a=mkdf(5,3,r_idx_nlevels=2,c_idx_nlevels=4)
"""
assert c_idx_nlevels > 0
assert r_idx_nlevels > 0
assert r_idx_type is None or (
r_idx_type in ("i", "f", "s", "u", "dt", "p", "td") and r_idx_nlevels == 1
)
assert c_idx_type is None or (
c_idx_type in ("i", "f", "s", "u", "dt", "p", "td") and c_idx_nlevels == 1
)
columns = makeCustomIndex(
ncols,
nlevels=c_idx_nlevels,
prefix="C",
names=c_idx_names,
ndupe_l=c_ndupe_l,
idx_type=c_idx_type,
)
index = makeCustomIndex(
nrows,
nlevels=r_idx_nlevels,
prefix="R",
names=r_idx_names,
ndupe_l=r_ndupe_l,
idx_type=r_idx_type,
)
# by default, generate data based on location
if data_gen_f is None:
data_gen_f = lambda r, c: f"R{r}C{c}"
data = [[data_gen_f(r, c) for c in range(ncols)] for r in range(nrows)]
return DataFrame(data, index, columns, dtype=dtype)
def _create_missing_idx(nrows, ncols, density, random_state=None):
if random_state is None:
random_state = np.random
else:
random_state = np.random.RandomState(random_state)
# below is cribbed from scipy.sparse
size = int(np.round((1 - density) * nrows * ncols))
# generate a few more to ensure unique values
min_rows = 5
fac = 1.02
extra_size = min(size + min_rows, fac * size)
def _gen_unique_rand(rng, _extra_size):
ind = rng.rand(int(_extra_size))
return np.unique(np.floor(ind * nrows * ncols))[:size]
ind = _gen_unique_rand(random_state, extra_size)
while ind.size < size:
extra_size *= 1.05
ind = _gen_unique_rand(random_state, extra_size)
j = np.floor(ind * 1.0 / nrows).astype(int)
i = (ind - j * nrows).astype(int)
return i.tolist(), j.tolist()
def makeMissingDataframe(density=0.9, random_state=None):
df = makeDataFrame()
i, j = _create_missing_idx(*df.shape, density=density, random_state=random_state)
df.values[i, j] = np.nan
return df
def optional_args(decorator):
"""
allows a decorator to take optional positional and keyword arguments.
Assumes that taking a single, callable, positional argument means that
it is decorating a function, i.e. something like this::
@my_decorator
def function(): pass
Calls decorator with decorator(f, *args, **kwargs)
"""
@wraps(decorator)
def wrapper(*args, **kwargs):
def dec(f):
return decorator(f, *args, **kwargs)
is_decorating = not kwargs and len(args) == 1 and callable(args[0])
if is_decorating:
f = args[0]
args = []
return dec(f)
else:
return dec
return wrapper
# skip tests on exceptions with this message
_network_error_messages = (
# 'urlopen error timed out',
# 'timeout: timed out',
# 'socket.timeout: timed out',
"timed out",
"Server Hangup",
"HTTP Error 503: Service Unavailable",
"502: Proxy Error",
"HTTP Error 502: internal error",
"HTTP Error 502",
"HTTP Error 503",
"HTTP Error 403",
"HTTP Error 400",
"Temporary failure in name resolution",
"Name or service not known",
"Connection refused",
"certificate verify",
)
# or this e.errno/e.reason.errno
_network_errno_vals = (
101, # Network is unreachable
111, # Connection refused
110, # Connection timed out
104, # Connection reset Error
54, # Connection reset by peer
60, # urllib.error.URLError: [Errno 60] Connection timed out
)
# Both of the above shouldn't mask real issues such as 404's
# or refused connections (changed DNS).
# But some tests (test_data yahoo) contact incredibly flakey
# servers.
# and conditionally raise on exception types in _get_default_network_errors
def _get_default_network_errors():
# Lazy import for http.client because it imports many things from the stdlib
import http.client
return (IOError, http.client.HTTPException, TimeoutError)
def can_connect(url, error_classes=None):
"""
Try to connect to the given url. True if succeeds, False if IOError
raised
Parameters
----------
url : basestring
The URL to try to connect to
Returns
-------
connectable : bool
Return True if no IOError (unable to connect) or URLError (bad url) was
raised
"""
if error_classes is None:
error_classes = _get_default_network_errors()
try:
with urlopen(url):
pass
except error_classes:
return False
else:
return True
@optional_args
def network(
t,
url="http://www.google.com",
raise_on_error=_RAISE_NETWORK_ERROR_DEFAULT,
check_before_test=False,
error_classes=None,
skip_errnos=_network_errno_vals,
_skip_on_messages=_network_error_messages,
):
"""
Label a test as requiring network connection and, if an error is
encountered, only raise if it does not find a network connection.
In comparison to ``network``, this assumes an added contract to your test:
you must assert that, under normal conditions, your test will ONLY fail if
it does not have network connectivity.
You can call this in 3 ways: as a standard decorator, with keyword
arguments, or with a positional argument that is the url to check.
Parameters
----------
t : callable
The test requiring network connectivity.
url : path
The url to test via ``pandas.io.common.urlopen`` to check
for connectivity. Defaults to 'http://www.google.com'.
raise_on_error : bool
If True, never catches errors.
check_before_test : bool
If True, checks connectivity before running the test case.
error_classes : tuple or Exception
error classes to ignore. If not in ``error_classes``, raises the error.
defaults to IOError. Be careful about changing the error classes here.
skip_errnos : iterable of int
Any exception that has .errno or .reason.erno set to one
of these values will be skipped with an appropriate
message.
_skip_on_messages: iterable of string
any exception e for which one of the strings is
a substring of str(e) will be skipped with an appropriate
message. Intended to suppress errors where an errno isn't available.
Notes
-----
* ``raise_on_error`` supercedes ``check_before_test``
Returns
-------
t : callable
The decorated test ``t``, with checks for connectivity errors.
Example
-------
Tests decorated with @network will fail if it's possible to make a network
connection to another URL (defaults to google.com)::
>>> from pandas._testing import network
>>> from pandas.io.common import urlopen
>>> @network
... def test_network():
... with urlopen("rabbit://bonanza.com"):
... pass
Traceback
...
URLError: <urlopen error unknown url type: rabit>
You can specify alternative URLs::
>>> @network("http://www.yahoo.com")
... def test_something_with_yahoo():
... raise IOError("Failure Message")
>>> test_something_with_yahoo()
Traceback (most recent call last):
...
IOError: Failure Message
If you set check_before_test, it will check the url first and not run the
test on failure::
>>> @network("failing://url.blaher", check_before_test=True)
... def test_something():
... print("I ran!")
... raise ValueError("Failure")
>>> test_something()
Traceback (most recent call last):
...
Errors not related to networking will always be raised.
"""
from pytest import skip
if error_classes is None:
error_classes = _get_default_network_errors()
t.network = True
@wraps(t)
def wrapper(*args, **kwargs):
if check_before_test and not raise_on_error:
if not can_connect(url, error_classes):
skip()
try:
return t(*args, **kwargs)
except Exception as err:
errno = getattr(err, "errno", None)
if not errno and hasattr(errno, "reason"):
errno = getattr(err.reason, "errno", None)
if errno in skip_errnos:
skip(f"Skipping test due to known errno and error {err}")
e_str = str(err)
if any(m.lower() in e_str.lower() for m in _skip_on_messages):
skip(
f"Skipping test because exception message is known and error {err}"
)
if not isinstance(err, error_classes):
raise
if raise_on_error or can_connect(url, error_classes):
raise
else:
skip(f"Skipping test due to lack of connectivity and error {err}")
return wrapper
with_connectivity_check = network
@contextmanager
def assert_produces_warning(
expected_warning=Warning,
filter_level="always",
check_stacklevel=True,
raise_on_extra_warnings=True,
):
"""
Context manager for running code expected to either raise a specific
warning, or not raise any warnings. Verifies that the code raises the
expected warning, and that it does not raise any other unexpected
warnings. It is basically a wrapper around ``warnings.catch_warnings``.
Parameters
----------
expected_warning : {Warning, False, None}, default Warning
The type of Exception raised. ``exception.Warning`` is the base
class for all warnings. To check that no warning is returned,
specify ``False`` or ``None``.
filter_level : str or None, default "always"
Specifies whether warnings are ignored, displayed, or turned
into errors.
Valid values are:
* "error" - turns matching warnings into exceptions
* "ignore" - discard the warning
* "always" - always emit a warning
* "default" - print the warning the first time it is generated
from each location
* "module" - print the warning the first time it is generated
from each module
* "once" - print the warning the first time it is generated
check_stacklevel : bool, default True
If True, displays the line that called the function containing
the warning to show were the function is called. Otherwise, the
line that implements the function is displayed.
raise_on_extra_warnings : bool, default True
Whether extra warnings not of the type `expected_warning` should
cause the test to fail.
Examples
--------
>>> import warnings
>>> with assert_produces_warning():
... warnings.warn(UserWarning())
...
>>> with assert_produces_warning(False):
... warnings.warn(RuntimeWarning())
...
Traceback (most recent call last):
...
AssertionError: Caused unexpected warning(s): ['RuntimeWarning'].
>>> with assert_produces_warning(UserWarning):
... warnings.warn(RuntimeWarning())
Traceback (most recent call last):
...
AssertionError: Did not see expected warning of class 'UserWarning'.
..warn:: This is *not* thread-safe.
"""
__tracebackhide__ = True
with warnings.catch_warnings(record=True) as w:
saw_warning = False
warnings.simplefilter(filter_level)
yield w
extra_warnings = []
for actual_warning in w:
if expected_warning and issubclass(
actual_warning.category, expected_warning
):
saw_warning = True
if check_stacklevel and issubclass(
actual_warning.category, (FutureWarning, DeprecationWarning)
):
from inspect import getframeinfo, stack
caller = getframeinfo(stack()[2][0])
msg = (
"Warning not set with correct stacklevel. "
f"File where warning is raised: {actual_warning.filename} != "
f"{caller.filename}. Warning message: {actual_warning.message}"
)
assert actual_warning.filename == caller.filename, msg
else:
extra_warnings.append(
(
actual_warning.category.__name__,
actual_warning.message,
actual_warning.filename,
actual_warning.lineno,
)
)
if expected_warning:
msg = (
f"Did not see expected warning of class "
f"{repr(expected_warning.__name__)}"
)
assert saw_warning, msg
if raise_on_extra_warnings and extra_warnings:
raise AssertionError(
f"Caused unexpected warning(s): {repr(extra_warnings)}"
)
class RNGContext:
"""
Context manager to set the numpy random number generator speed. Returns
to the original value upon exiting the context manager.
Parameters
----------
seed : int
Seed for numpy.random.seed
Examples
--------
with RNGContext(42):
np.random.randn()
"""
def __init__(self, seed):
self.seed = seed
def __enter__(self):
self.start_state = np.random.get_state()
np.random.seed(self.seed)
def __exit__(self, exc_type, exc_value, traceback):
np.random.set_state(self.start_state)
@contextmanager
def with_csv_dialect(name, **kwargs):
"""
Context manager to temporarily register a CSV dialect for parsing CSV.
Parameters
----------
name : str
The name of the dialect.
kwargs : mapping
The parameters for the dialect.
Raises
------
ValueError : the name of the dialect conflicts with a builtin one.
See Also
--------
csv : Python's CSV library.
"""
import csv
_BUILTIN_DIALECTS = {"excel", "excel-tab", "unix"}
if name in _BUILTIN_DIALECTS:
raise ValueError("Cannot override builtin dialect.")
csv.register_dialect(name, **kwargs)
yield
csv.unregister_dialect(name)
@contextmanager
def use_numexpr(use, min_elements=None):
from pandas.core.computation import expressions as expr
if min_elements is None:
min_elements = expr._MIN_ELEMENTS
olduse = expr._USE_NUMEXPR
oldmin = expr._MIN_ELEMENTS
expr.set_use_numexpr(use)
expr._MIN_ELEMENTS = min_elements
yield
expr._MIN_ELEMENTS = oldmin
expr.set_use_numexpr(olduse)
def test_parallel(num_threads=2, kwargs_list=None):
"""
Decorator to run the same function multiple times in parallel.
Parameters
----------
num_threads : int, optional
The number of times the function is run in parallel.
kwargs_list : list of dicts, optional
The list of kwargs to update original
function kwargs on different threads.
Notes
-----
This decorator does not pass the return value of the decorated function.
Original from scikit-image:
https://github.com/scikit-image/scikit-image/pull/1519
"""
assert num_threads > 0
has_kwargs_list = kwargs_list is not None
if has_kwargs_list:
assert len(kwargs_list) == num_threads
import threading
def wrapper(func):
@wraps(func)
def inner(*args, **kwargs):
if has_kwargs_list:
update_kwargs = lambda i: dict(kwargs, **kwargs_list[i])
else:
update_kwargs = lambda i: kwargs
threads = []
for i in range(num_threads):
updated_kwargs = update_kwargs(i)
thread = threading.Thread(target=func, args=args, kwargs=updated_kwargs)
threads.append(thread)
for thread in threads:
thread.start()
for thread in threads:
thread.join()
return inner
return wrapper
class SubclassedSeries(Series):
_metadata = ["testattr", "name"]
@property
def _constructor(self):
return SubclassedSeries
@property
def _constructor_expanddim(self):
return SubclassedDataFrame
class SubclassedDataFrame(DataFrame):
_metadata = ["testattr"]
@property
def _constructor(self):
return SubclassedDataFrame
@property
def _constructor_sliced(self):
return SubclassedSeries
class SubclassedCategorical(Categorical):
@property
def _constructor(self):
return SubclassedCategorical
@contextmanager
def set_timezone(tz: str):
"""
Context manager for temporarily setting a timezone.
Parameters
----------
tz : str
A string representing a valid timezone.
Examples
--------
>>> from datetime import datetime
>>> from dateutil.tz import tzlocal
>>> tzlocal().tzname(datetime.now())
'IST'
>>> with set_timezone('US/Eastern'):
... tzlocal().tzname(datetime.now())
...
'EDT'
"""
import os
import time
def setTZ(tz):
if tz is None:
try:
del os.environ["TZ"]
except KeyError:
pass
else:
os.environ["TZ"] = tz
time.tzset()
orig_tz = os.environ.get("TZ")
setTZ(tz)
try:
yield
finally:
setTZ(orig_tz)
def _make_skipna_wrapper(alternative, skipna_alternative=None):
"""
Create a function for calling on an array.
Parameters
----------
alternative : function
The function to be called on the array with no NaNs.
Only used when 'skipna_alternative' is None.
skipna_alternative : function
The function to be called on the original array
Returns
-------
function
"""
if skipna_alternative:
def skipna_wrapper(x):
return skipna_alternative(x.values)
else:
def skipna_wrapper(x):
nona = x.dropna()
if len(nona) == 0:
return np.nan
return alternative(nona)
return skipna_wrapper
def convert_rows_list_to_csv_str(rows_list: List[str]):
"""
Convert list of CSV rows to single CSV-formatted string for current OS.
This method is used for creating expected value of to_csv() method.
Parameters
----------
rows_list : List[str]
Each element represents the row of csv.
Returns
-------
str
Expected output of to_csv() in current OS.
"""
sep = os.linesep
expected = sep.join(rows_list) + sep
return expected
def external_error_raised(
expected_exception: Type[Exception],
) -> Callable[[Type[Exception], None], None]:
"""
Helper function to mark pytest.raises that have an external error message.
Parameters
----------
expected_exception : Exception
Expected error to raise.
Returns
-------
Callable
Regular `pytest.raises` function with `match` equal to `None`.
"""
import pytest
return pytest.raises(expected_exception, match=None)
| BugsInPy/BugsInPy/temp/projects/pandas/bug-42-fixed/pandas/pandas/_testing.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-42-buggy/pandas/pandas/_testing.py |
pandas-bug-14 | """
Functions for defining unary operations.
"""
from typing import Any
from pandas._typing import ArrayLike
from pandas.core.dtypes.common import (
is_datetime64_dtype,
is_integer_dtype,
is_object_dtype,
is_timedelta64_dtype,
)
from pandas.core.dtypes.generic import ABCExtensionArray
def should_extension_dispatch(left: ArrayLike, right: Any) -> bool:
"""
Identify cases where Series operation should dispatch to ExtensionArray method.
Parameters
----------
left : np.ndarray or ExtensionArray
right : object
Returns
-------
bool
"""
return isinstance(left, ABCExtensionArray) or isinstance(right, ABCExtensionArray)
def should_series_dispatch(left, right, op):
"""
Identify cases where a DataFrame operation should dispatch to its
Series counterpart.
Parameters
----------
left : DataFrame
right : DataFrame or Series
op : binary operator
Returns
-------
override : bool
"""
if left._is_mixed_type or right._is_mixed_type:
return True
if op.__name__.strip("_") in ["and", "or", "xor", "rand", "ror", "rxor"]:
# TODO: GH references for what this fixes
# Note: this check must come before the check for nonempty columns.
return True
if right.ndim == 1:
# operating with Series, short-circuit checks that would fail
# with AttributeError.
return False
if not len(left.columns) or not len(right.columns):
# ensure obj.dtypes[0] exists for each obj
return False
ldtype = left.dtypes.iloc[0]
rdtype = right.dtypes.iloc[0]
if (is_timedelta64_dtype(ldtype) and is_integer_dtype(rdtype)) or (
is_timedelta64_dtype(rdtype) and is_integer_dtype(ldtype)
):
# numpy integer dtypes as timedelta64 dtypes in this scenario
return True
if is_datetime64_dtype(ldtype) and is_object_dtype(rdtype):
# in particular case where right is an array of DateOffsets
return True
return False
"""
Functions for defining unary operations.
"""
from typing import Any
from pandas._typing import ArrayLike
from pandas.core.dtypes.common import (
is_datetime64_dtype,
is_integer_dtype,
is_object_dtype,
is_timedelta64_dtype,
)
from pandas.core.dtypes.generic import ABCExtensionArray
def should_extension_dispatch(left: ArrayLike, right: Any) -> bool:
"""
Identify cases where Series operation should dispatch to ExtensionArray method.
Parameters
----------
left : np.ndarray or ExtensionArray
right : object
Returns
-------
bool
"""
return isinstance(left, ABCExtensionArray) or isinstance(right, ABCExtensionArray)
def should_series_dispatch(left, right, op):
"""
Identify cases where a DataFrame operation should dispatch to its
Series counterpart.
Parameters
----------
left : DataFrame
right : DataFrame or Series
op : binary operator
Returns
-------
override : bool
"""
if left._is_mixed_type or right._is_mixed_type:
return True
if op.__name__.strip("_") in ["and", "or", "xor", "rand", "ror", "rxor"]:
# TODO: GH references for what this fixes
# Note: this check must come before the check for nonempty columns.
return True
if right.ndim == 1:
# operating with Series, short-circuit checks that would fail
# with AttributeError.
return False
if not len(left.columns) or not len(right.columns):
# ensure obj.dtypes[0] exists for each obj
return False
ldtype = left.dtypes.iloc[0]
rdtype = right.dtypes.iloc[0]
if (is_timedelta64_dtype(ldtype) and is_integer_dtype(rdtype)) or (
is_timedelta64_dtype(rdtype) and is_integer_dtype(ldtype)
):
# numpy integer dtypes as timedelta64 dtypes in this scenario
return True
if (is_datetime64_dtype(ldtype) and is_object_dtype(rdtype)) or (
is_datetime64_dtype(rdtype) and is_object_dtype(ldtype)
):
# in particular case where one is an array of DateOffsets
return True
return False
| BugsInPy/BugsInPy/temp/projects/pandas/bug-14-fixed/pandas/pandas/core/ops/dispatch.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-14-buggy/pandas/pandas/core/ops/dispatch.py |
pandas-bug-147 | """ define extension dtypes """
import re
from typing import Any, Dict, List, Optional, Tuple, Type, Union, cast
import warnings
import numpy as np
import pytz
from pandas._libs.interval import Interval
from pandas._libs.tslibs import NaT, Period, Timestamp, timezones
from pandas.core.dtypes.generic import ABCCategoricalIndex, ABCDateOffset, ABCIndexClass
from pandas._typing import Ordered
from .base import ExtensionDtype
from .inference import is_bool, is_list_like
str_type = str
# GH26403: sentinel value used for the default value of ordered in the
# CategoricalDtype constructor to detect when ordered=None is explicitly passed
ordered_sentinel = object() # type: object
def register_extension_dtype(cls: Type[ExtensionDtype]) -> Type[ExtensionDtype]:
"""
Register an ExtensionType with pandas as class decorator.
.. versionadded:: 0.24.0
This enables operations like ``.astype(name)`` for the name
of the ExtensionDtype.
Returns
-------
callable
A class decorator.
Examples
--------
>>> from pandas.api.extensions import register_extension_dtype
>>> from pandas.api.extensions import ExtensionDtype
>>> @register_extension_dtype
... class MyExtensionDtype(ExtensionDtype):
... pass
"""
registry.register(cls)
return cls
class Registry:
"""
Registry for dtype inference
The registry allows one to map a string repr of a extension
dtype to an extension dtype. The string alias can be used in several
places, including
* Series and Index constructors
* :meth:`pandas.array`
* :meth:`pandas.Series.astype`
Multiple extension types can be registered.
These are tried in order.
"""
def __init__(self):
self.dtypes = [] # type: List[Type[ExtensionDtype]]
def register(self, dtype: Type[ExtensionDtype]) -> None:
"""
Parameters
----------
dtype : ExtensionDtype
"""
if not issubclass(dtype, ExtensionDtype):
raise ValueError("can only register pandas extension dtypes")
self.dtypes.append(dtype)
def find(
self, dtype: Union[Type[ExtensionDtype], str]
) -> Optional[Type[ExtensionDtype]]:
"""
Parameters
----------
dtype : Type[ExtensionDtype] or string
Returns
-------
return the first matching dtype, otherwise return None
"""
if not isinstance(dtype, str):
dtype_type = dtype
if not isinstance(dtype, type):
dtype_type = type(dtype)
if issubclass(dtype_type, ExtensionDtype):
return dtype
return None
for dtype_type in self.dtypes:
try:
return dtype_type.construct_from_string(dtype)
except TypeError:
pass
return None
registry = Registry()
class PandasExtensionDtype(ExtensionDtype):
"""
A np.dtype duck-typed class, suitable for holding a custom dtype.
THIS IS NOT A REAL NUMPY DTYPE
"""
type = None # type: Any
kind = None # type: Any
# The Any type annotations above are here only because mypy seems to have a
# problem dealing with with multiple inheritance from PandasExtensionDtype
# and ExtensionDtype's @properties in the subclasses below. The kind and
# type variables in those subclasses are explicitly typed below.
subdtype = None
str = None # type: Optional[str_type]
num = 100
shape = tuple() # type: Tuple[int, ...]
itemsize = 8
base = None
isbuiltin = 0
isnative = 0
_cache = {} # type: Dict[str_type, 'PandasExtensionDtype']
def __str__(self) -> str_type:
"""
Return a string representation for a particular Object
"""
return self.name
def __repr__(self) -> str_type:
"""
Return a string representation for a particular object.
"""
return str(self)
def __hash__(self) -> int:
raise NotImplementedError("sub-classes should implement an __hash__ method")
def __getstate__(self) -> Dict[str_type, Any]:
# pickle support; we don't want to pickle the cache
return {k: getattr(self, k, None) for k in self._metadata}
@classmethod
def reset_cache(cls) -> None:
""" clear the cache """
cls._cache = {}
class CategoricalDtypeType(type):
"""
the type of CategoricalDtype, this metaclass determines subclass ability
"""
pass
@register_extension_dtype
class CategoricalDtype(PandasExtensionDtype, ExtensionDtype):
"""
Type for categorical data with the categories and orderedness.
.. versionchanged:: 0.21.0
Parameters
----------
categories : sequence, optional
Must be unique, and must not contain any nulls.
ordered : bool, default False
Attributes
----------
categories
ordered
Methods
-------
None
See Also
--------
Categorical
Notes
-----
This class is useful for specifying the type of a ``Categorical``
independent of the values. See :ref:`categorical.categoricaldtype`
for more.
Examples
--------
>>> t = pd.CategoricalDtype(categories=['b', 'a'], ordered=True)
>>> pd.Series(['a', 'b', 'a', 'c'], dtype=t)
0 a
1 b
2 a
3 NaN
dtype: category
Categories (2, object): [b < a]
"""
# TODO: Document public vs. private API
name = "category"
type = CategoricalDtypeType # type: Type[CategoricalDtypeType]
kind = "O" # type: str_type
str = "|O08"
base = np.dtype("O")
_metadata = ("categories", "ordered", "_ordered_from_sentinel")
_cache = {} # type: Dict[str_type, PandasExtensionDtype]
def __init__(
self, categories=None, ordered: Union[Ordered, object] = ordered_sentinel
):
# TODO(GH26403): Set type of ordered to Ordered
ordered = cast(Ordered, ordered)
self._finalize(categories, ordered, fastpath=False)
@classmethod
def _from_fastpath(
cls, categories=None, ordered: Optional[bool] = None
) -> "CategoricalDtype":
self = cls.__new__(cls)
self._finalize(categories, ordered, fastpath=True)
return self
@classmethod
def _from_categorical_dtype(
cls, dtype: "CategoricalDtype", categories=None, ordered: Ordered = None
) -> "CategoricalDtype":
if categories is ordered is None:
return dtype
if categories is None:
categories = dtype.categories
if ordered is None:
ordered = dtype.ordered
return cls(categories, ordered)
@classmethod
def _from_values_or_dtype(
cls,
values=None,
categories=None,
ordered: Optional[bool] = None,
dtype: Optional["CategoricalDtype"] = None,
) -> "CategoricalDtype":
"""
Construct dtype from the input parameters used in :class:`Categorical`.
This constructor method specifically does not do the factorization
step, if that is needed to find the categories. This constructor may
therefore return ``CategoricalDtype(categories=None, ordered=None)``,
which may not be useful. Additional steps may therefore have to be
taken to create the final dtype.
The return dtype is specified from the inputs in this prioritized
order:
1. if dtype is a CategoricalDtype, return dtype
2. if dtype is the string 'category', create a CategoricalDtype from
the supplied categories and ordered parameters, and return that.
3. if values is a categorical, use value.dtype, but override it with
categories and ordered if either/both of those are not None.
4. if dtype is None and values is not a categorical, construct the
dtype from categories and ordered, even if either of those is None.
Parameters
----------
values : list-like, optional
The list-like must be 1-dimensional.
categories : list-like, optional
Categories for the CategoricalDtype.
ordered : bool, optional
Designating if the categories are ordered.
dtype : CategoricalDtype or the string "category", optional
If ``CategoricalDtype``, cannot be used together with
`categories` or `ordered`.
Returns
-------
CategoricalDtype
Examples
--------
>>> CategoricalDtype._from_values_or_dtype()
CategoricalDtype(categories=None, ordered=None)
>>> CategoricalDtype._from_values_or_dtype(categories=['a', 'b'],
... ordered=True)
CategoricalDtype(categories=['a', 'b'], ordered=True)
>>> dtype1 = CategoricalDtype(['a', 'b'], ordered=True)
>>> dtype2 = CategoricalDtype(['x', 'y'], ordered=False)
>>> c = Categorical([0, 1], dtype=dtype1, fastpath=True)
>>> CategoricalDtype._from_values_or_dtype(c, ['x', 'y'], ordered=True,
... dtype=dtype2)
ValueError: Cannot specify `categories` or `ordered` together with
`dtype`.
The supplied dtype takes precedence over values' dtype:
>>> CategoricalDtype._from_values_or_dtype(c, dtype=dtype2)
CategoricalDtype(['x', 'y'], ordered=False)
"""
from pandas.core.dtypes.common import is_categorical
if dtype is not None:
# The dtype argument takes precedence over values.dtype (if any)
if isinstance(dtype, str):
if dtype == "category":
dtype = CategoricalDtype(categories, ordered)
else:
msg = "Unknown dtype {dtype!r}"
raise ValueError(msg.format(dtype=dtype))
elif categories is not None or ordered is not None:
raise ValueError(
"Cannot specify `categories` or `ordered` together with `dtype`."
)
elif is_categorical(values):
# If no "dtype" was passed, use the one from "values", but honor
# the "ordered" and "categories" arguments
dtype = values.dtype._from_categorical_dtype(
values.dtype, categories, ordered
)
else:
# If dtype=None and values is not categorical, create a new dtype.
# Note: This could potentially have categories=None and
# ordered=None.
dtype = CategoricalDtype(categories, ordered)
return dtype
def _finalize(self, categories, ordered: Ordered, fastpath: bool = False) -> None:
if ordered is not None and ordered is not ordered_sentinel:
self.validate_ordered(ordered)
if categories is not None:
categories = self.validate_categories(categories, fastpath=fastpath)
self._categories = categories
self._ordered = ordered if ordered is not ordered_sentinel else None
self._ordered_from_sentinel = ordered is ordered_sentinel
def __setstate__(self, state: Dict[str_type, Any]) -> None:
# for pickle compat. __get_state__ is defined in the
# PandasExtensionDtype superclass and uses the public properties to
# pickle -> need to set the settable private ones here (see GH26067)
self._categories = state.pop("categories", None)
self._ordered = state.pop("ordered", False)
self._ordered_from_sentinel = state.pop("_ordered_from_sentinel", False)
def __hash__(self) -> int:
# _hash_categories returns a uint64, so use the negative
# space for when we have unknown categories to avoid a conflict
if self.categories is None:
if self._ordered:
return -1
else:
return -2
# We *do* want to include the real self.ordered here
return int(self._hash_categories(self.categories, self._ordered))
def __eq__(self, other: Any) -> bool:
"""
Rules for CDT equality:
1) Any CDT is equal to the string 'category'
2) Any CDT is equal to itself
3) Any CDT is equal to a CDT with categories=None regardless of ordered
4) A CDT with ordered=True is only equal to another CDT with
ordered=True and identical categories in the same order
5) A CDT with ordered={False, None} is only equal to another CDT with
ordered={False, None} and identical categories, but same order is
not required. There is no distinction between False/None.
6) Any other comparison returns False
"""
if isinstance(other, str):
return other == self.name
elif other is self:
return True
elif not (hasattr(other, "_ordered") and hasattr(other, "categories")):
return False
elif self.categories is None or other.categories is None:
# We're forced into a suboptimal corner thanks to math and
# backwards compatibility. We require that `CDT(...) == 'category'`
# for all CDTs **including** `CDT(None, ...)`. Therefore, *all*
# CDT(., .) = CDT(None, False) and *all*
# CDT(., .) = CDT(None, True).
return True
elif self._ordered or other._ordered:
# At least one has ordered=True; equal if both have ordered=True
# and the same values for categories in the same order.
return (self._ordered == other._ordered) and self.categories.equals(
other.categories
)
else:
# Neither has ordered=True; equal if both have the same categories,
# but same order is not necessary. There is no distinction between
# ordered=False and ordered=None: CDT(., False) and CDT(., None)
# will be equal if they have the same categories.
if (
self.categories.dtype == other.categories.dtype
and self.categories.equals(other.categories)
):
# Check and see if they happen to be identical categories
return True
return hash(self) == hash(other)
def __repr__(self):
tpl = "CategoricalDtype(categories={}ordered={})"
if self.categories is None:
data = "None, "
else:
data = self.categories._format_data(name=self.__class__.__name__)
return tpl.format(data, self._ordered)
@staticmethod
def _hash_categories(categories, ordered: Ordered = True) -> int:
from pandas.core.util.hashing import (
hash_array,
_combine_hash_arrays,
hash_tuples,
)
from pandas.core.dtypes.common import is_datetime64tz_dtype, _NS_DTYPE
if len(categories) and isinstance(categories[0], tuple):
# assumes if any individual category is a tuple, then all our. ATM
# I don't really want to support just some of the categories being
# tuples.
categories = list(categories) # breaks if a np.array of categories
cat_array = hash_tuples(categories)
else:
if categories.dtype == "O":
if len({type(x) for x in categories}) != 1:
# TODO: hash_array doesn't handle mixed types. It casts
# everything to a str first, which means we treat
# {'1', '2'} the same as {'1', 2}
# find a better solution
hashed = hash((tuple(categories), ordered))
return hashed
if is_datetime64tz_dtype(categories.dtype):
# Avoid future warning.
categories = categories.astype(_NS_DTYPE)
cat_array = hash_array(np.asarray(categories), categorize=False)
if ordered:
cat_array = np.vstack(
[cat_array, np.arange(len(cat_array), dtype=cat_array.dtype)]
)
else:
cat_array = [cat_array]
hashed = _combine_hash_arrays(iter(cat_array), num_items=len(cat_array))
return np.bitwise_xor.reduce(hashed)
@classmethod
def construct_array_type(cls):
"""
Return the array type associated with this dtype
Returns
-------
type
"""
from pandas import Categorical
return Categorical
@staticmethod
def validate_ordered(ordered: Ordered) -> None:
"""
Validates that we have a valid ordered parameter. If
it is not a boolean, a TypeError will be raised.
Parameters
----------
ordered : object
The parameter to be verified.
Raises
------
TypeError
If 'ordered' is not a boolean.
"""
if not is_bool(ordered):
raise TypeError("'ordered' must either be 'True' or 'False'")
@staticmethod
def validate_categories(categories, fastpath: bool = False):
"""
Validates that we have good categories
Parameters
----------
categories : array-like
fastpath : bool
Whether to skip nan and uniqueness checks
Returns
-------
categories : Index
"""
from pandas.core.indexes.base import Index
if not fastpath and not is_list_like(categories):
msg = "Parameter 'categories' must be list-like, was {!r}"
raise TypeError(msg.format(categories))
elif not isinstance(categories, ABCIndexClass):
categories = Index(categories, tupleize_cols=False)
if not fastpath:
if categories.hasnans:
raise ValueError("Categorial categories cannot be null")
if not categories.is_unique:
raise ValueError("Categorical categories must be unique")
if isinstance(categories, ABCCategoricalIndex):
categories = categories.categories
return categories
def update_dtype(
self, dtype: Union[str_type, "CategoricalDtype"]
) -> "CategoricalDtype":
"""
Returns a CategoricalDtype with categories and ordered taken from dtype
if specified, otherwise falling back to self if unspecified
Parameters
----------
dtype : CategoricalDtype
Returns
-------
new_dtype : CategoricalDtype
"""
if isinstance(dtype, str) and dtype == "category":
# dtype='category' should not change anything
return self
elif not self.is_dtype(dtype):
msg = (
"a CategoricalDtype must be passed to perform an update, "
"got {dtype!r}"
).format(dtype=dtype)
raise ValueError(msg)
else:
# from here on, dtype is a CategoricalDtype
dtype = cast(CategoricalDtype, dtype)
# dtype is CDT: keep current categories/ordered if None
new_categories = dtype.categories
if new_categories is None:
new_categories = self.categories
new_ordered = dtype._ordered
new_ordered_from_sentinel = dtype._ordered_from_sentinel
if new_ordered is None:
# maintain existing ordered if new dtype has ordered=None
new_ordered = self._ordered
if self._ordered and new_ordered_from_sentinel:
# only warn if we'd actually change the existing behavior
msg = (
"Constructing a CategoricalDtype without specifying "
"`ordered` will default to `ordered=False` in a future "
"version, which will cause the resulting categorical's "
"`ordered` attribute to change to False; `ordered=True`"
" must be explicitly passed in order to be retained"
)
warnings.warn(msg, FutureWarning, stacklevel=3)
return CategoricalDtype(new_categories, new_ordered)
@property
def categories(self):
"""
An ``Index`` containing the unique categories allowed.
"""
return self._categories
@property
def ordered(self) -> Ordered:
"""
Whether the categories have an ordered relationship.
"""
# TODO: remove if block when ordered=None as default is deprecated
if self._ordered_from_sentinel and self._ordered is None:
# warn when accessing ordered if ordered=None and None was not
# explicitly passed to the constructor
msg = (
"Constructing a CategoricalDtype without specifying "
"`ordered` will default to `ordered=False` in a future "
"version; `ordered=None` must be explicitly passed."
)
warnings.warn(msg, FutureWarning, stacklevel=2)
return self._ordered
@property
def _is_boolean(self) -> bool:
from pandas.core.dtypes.common import is_bool_dtype
return is_bool_dtype(self.categories)
@register_extension_dtype
class DatetimeTZDtype(PandasExtensionDtype):
"""
An ExtensionDtype for timezone-aware datetime data.
**This is not an actual numpy dtype**, but a duck type.
Parameters
----------
unit : str, default "ns"
The precision of the datetime data. Currently limited
to ``"ns"``.
tz : str, int, or datetime.tzinfo
The timezone.
Attributes
----------
unit
tz
Methods
-------
None
Raises
------
pytz.UnknownTimeZoneError
When the requested timezone cannot be found.
Examples
--------
>>> pd.DatetimeTZDtype(tz='UTC')
datetime64[ns, UTC]
>>> pd.DatetimeTZDtype(tz='dateutil/US/Central')
datetime64[ns, tzfile('/usr/share/zoneinfo/US/Central')]
"""
type = Timestamp # type: Type[Timestamp]
kind = "M" # type: str_type
str = "|M8[ns]"
num = 101
base = np.dtype("M8[ns]")
na_value = NaT
_metadata = ("unit", "tz")
_match = re.compile(r"(datetime64|M8)\[(?P<unit>.+), (?P<tz>.+)\]")
_cache = {} # type: Dict[str_type, PandasExtensionDtype]
def __init__(self, unit="ns", tz=None):
if isinstance(unit, DatetimeTZDtype):
unit, tz = unit.unit, unit.tz
if unit != "ns":
if isinstance(unit, str) and tz is None:
# maybe a string like datetime64[ns, tz], which we support for
# now.
result = type(self).construct_from_string(unit)
unit = result.unit
tz = result.tz
msg = (
"Passing a dtype alias like 'datetime64[ns, {tz}]' "
"to DatetimeTZDtype is deprecated. Use "
"'DatetimeTZDtype.construct_from_string()' instead."
)
warnings.warn(msg.format(tz=tz), FutureWarning, stacklevel=2)
else:
raise ValueError("DatetimeTZDtype only supports ns units")
if tz:
tz = timezones.maybe_get_tz(tz)
tz = timezones.tz_standardize(tz)
elif tz is not None:
raise pytz.UnknownTimeZoneError(tz)
elif tz is None:
raise TypeError("A 'tz' is required.")
self._unit = unit
self._tz = tz
@property
def unit(self):
"""
The precision of the datetime data.
"""
return self._unit
@property
def tz(self):
"""
The timezone.
"""
return self._tz
@classmethod
def construct_array_type(cls):
"""
Return the array type associated with this dtype
Returns
-------
type
"""
from pandas.core.arrays import DatetimeArray
return DatetimeArray
@classmethod
def construct_from_string(cls, string):
"""
Construct a DatetimeTZDtype from a string.
Parameters
----------
string : str
The string alias for this DatetimeTZDtype.
Should be formatted like ``datetime64[ns, <tz>]``,
where ``<tz>`` is the timezone name.
Examples
--------
>>> DatetimeTZDtype.construct_from_string('datetime64[ns, UTC]')
datetime64[ns, UTC]
"""
if isinstance(string, str):
msg = "Could not construct DatetimeTZDtype from '{}'"
try:
match = cls._match.match(string)
if match:
d = match.groupdict()
return cls(unit=d["unit"], tz=d["tz"])
except Exception:
# TODO(py3): Change this pass to `raise TypeError(msg) from e`
pass
raise TypeError(msg.format(string))
raise TypeError("Could not construct DatetimeTZDtype")
def __str__(self):
return "datetime64[{unit}, {tz}]".format(unit=self.unit, tz=self.tz)
@property
def name(self):
"""A string representation of the dtype."""
return str(self)
def __hash__(self):
# make myself hashable
# TODO: update this.
return hash(str(self))
def __eq__(self, other):
if isinstance(other, str):
return other == self.name
return (
isinstance(other, DatetimeTZDtype)
and self.unit == other.unit
and str(self.tz) == str(other.tz)
)
def __setstate__(self, state):
# for pickle compat. __get_state__ is defined in the
# PandasExtensionDtype superclass and uses the public properties to
# pickle -> need to set the settable private ones here (see GH26067)
self._tz = state["tz"]
self._unit = state["unit"]
@register_extension_dtype
class PeriodDtype(PandasExtensionDtype):
"""
An ExtensionDtype for Period data.
**This is not an actual numpy dtype**, but a duck type.
Parameters
----------
freq : str or DateOffset
The frequency of this PeriodDtype
Attributes
----------
freq
Methods
-------
None
Examples
--------
>>> pd.PeriodDtype(freq='D')
period[D]
>>> pd.PeriodDtype(freq=pd.offsets.MonthEnd())
period[M]
"""
type = Period # type: Type[Period]
kind = "O" # type: str_type
str = "|O08"
base = np.dtype("O")
num = 102
_metadata = ("freq",)
_match = re.compile(r"(P|p)eriod\[(?P<freq>.+)\]")
_cache = {} # type: Dict[str_type, PandasExtensionDtype]
def __new__(cls, freq=None):
"""
Parameters
----------
freq : frequency
"""
if isinstance(freq, PeriodDtype):
return freq
elif freq is None:
# empty constructor for pickle compat
u = object.__new__(cls)
u._freq = None
return u
if not isinstance(freq, ABCDateOffset):
freq = cls._parse_dtype_strict(freq)
try:
return cls._cache[freq.freqstr]
except KeyError:
u = object.__new__(cls)
u._freq = freq
cls._cache[freq.freqstr] = u
return u
@property
def freq(self):
"""
The frequency object of this PeriodDtype.
"""
return self._freq
@classmethod
def _parse_dtype_strict(cls, freq):
if isinstance(freq, str):
if freq.startswith("period[") or freq.startswith("Period["):
m = cls._match.search(freq)
if m is not None:
freq = m.group("freq")
from pandas.tseries.frequencies import to_offset
freq = to_offset(freq)
if freq is not None:
return freq
raise ValueError("could not construct PeriodDtype")
@classmethod
def construct_from_string(cls, string):
"""
Strict construction from a string, raise a TypeError if not
possible
"""
if (
isinstance(string, str)
and (string.startswith("period[") or string.startswith("Period["))
or isinstance(string, ABCDateOffset)
):
# do not parse string like U as period[U]
# avoid tuple to be regarded as freq
try:
return cls(freq=string)
except ValueError:
pass
raise TypeError("could not construct PeriodDtype")
def __str__(self):
return self.name
@property
def name(self):
return "period[{freq}]".format(freq=self.freq.freqstr)
@property
def na_value(self):
return NaT
def __hash__(self):
# make myself hashable
return hash(str(self))
def __eq__(self, other):
if isinstance(other, str):
return other == self.name or other == self.name.title()
return isinstance(other, PeriodDtype) and self.freq == other.freq
def __setstate__(self, state):
# for pickle compat. __get_state__ is defined in the
# PandasExtensionDtype superclass and uses the public properties to
# pickle -> need to set the settable private ones here (see GH26067)
self._freq = state["freq"]
@classmethod
def is_dtype(cls, dtype):
"""
Return a boolean if we if the passed type is an actual dtype that we
can match (via string or type)
"""
if isinstance(dtype, str):
# PeriodDtype can be instantiated from freq string like "U",
# but doesn't regard freq str like "U" as dtype.
if dtype.startswith("period[") or dtype.startswith("Period["):
try:
if cls._parse_dtype_strict(dtype) is not None:
return True
else:
return False
except ValueError:
return False
else:
return False
return super().is_dtype(dtype)
@classmethod
def construct_array_type(cls):
from pandas.core.arrays import PeriodArray
return PeriodArray
@register_extension_dtype
class IntervalDtype(PandasExtensionDtype):
"""
An ExtensionDtype for Interval data.
**This is not an actual numpy dtype**, but a duck type.
Parameters
----------
subtype : str, np.dtype
The dtype of the Interval bounds.
Attributes
----------
subtype
Methods
-------
None
Examples
--------
>>> pd.IntervalDtype(subtype='int64')
interval[int64]
"""
name = "interval"
kind = None # type: Optional[str_type]
str = "|O08"
base = np.dtype("O")
num = 103
_metadata = ("subtype",)
_match = re.compile(r"(I|i)nterval\[(?P<subtype>.+)\]")
_cache = {} # type: Dict[str_type, PandasExtensionDtype]
def __new__(cls, subtype=None):
from pandas.core.dtypes.common import (
is_categorical_dtype,
is_string_dtype,
pandas_dtype,
)
if isinstance(subtype, IntervalDtype):
return subtype
elif subtype is None:
# we are called as an empty constructor
# generally for pickle compat
u = object.__new__(cls)
u._subtype = None
return u
elif isinstance(subtype, str) and subtype.lower() == "interval":
subtype = None
else:
if isinstance(subtype, str):
m = cls._match.search(subtype)
if m is not None:
subtype = m.group("subtype")
try:
subtype = pandas_dtype(subtype)
except TypeError:
raise TypeError("could not construct IntervalDtype")
if is_categorical_dtype(subtype) or is_string_dtype(subtype):
# GH 19016
msg = (
"category, object, and string subtypes are not supported "
"for IntervalDtype"
)
raise TypeError(msg)
try:
return cls._cache[str(subtype)]
except KeyError:
u = object.__new__(cls)
u._subtype = subtype
cls._cache[str(subtype)] = u
return u
@property
def subtype(self):
"""
The dtype of the Interval bounds.
"""
return self._subtype
@classmethod
def construct_array_type(cls):
"""
Return the array type associated with this dtype
Returns
-------
type
"""
from pandas.core.arrays import IntervalArray
return IntervalArray
@classmethod
def construct_from_string(cls, string):
"""
attempt to construct this type from a string, raise a TypeError
if its not possible
"""
if not isinstance(string, str):
msg = "a string needs to be passed, got type {typ}"
raise TypeError(msg.format(typ=type(string)))
if string.lower() == "interval" or cls._match.search(string) is not None:
return cls(string)
msg = (
"Incorrectly formatted string passed to constructor. "
"Valid formats include Interval or Interval[dtype] "
"where dtype is numeric, datetime, or timedelta"
)
raise TypeError(msg)
@property
def type(self):
return Interval
def __str__(self):
if self.subtype is None:
return "interval"
return "interval[{subtype}]".format(subtype=self.subtype)
def __hash__(self):
# make myself hashable
return hash(str(self))
def __eq__(self, other):
if isinstance(other, str):
return other.lower() in (self.name.lower(), str(self).lower())
elif not isinstance(other, IntervalDtype):
return False
elif self.subtype is None or other.subtype is None:
# None should match any subtype
return True
else:
from pandas.core.dtypes.common import is_dtype_equal
return is_dtype_equal(self.subtype, other.subtype)
def __setstate__(self, state):
# for pickle compat. __get_state__ is defined in the
# PandasExtensionDtype superclass and uses the public properties to
# pickle -> need to set the settable private ones here (see GH26067)
self._subtype = state["subtype"]
@classmethod
def is_dtype(cls, dtype):
"""
Return a boolean if we if the passed type is an actual dtype that we
can match (via string or type)
"""
if isinstance(dtype, str):
if dtype.lower().startswith("interval"):
try:
if cls.construct_from_string(dtype) is not None:
return True
else:
return False
except (ValueError, TypeError):
return False
else:
return False
return super().is_dtype(dtype)
""" define extension dtypes """
import re
from typing import Any, Dict, List, Optional, Tuple, Type, Union, cast
import warnings
import numpy as np
import pytz
from pandas._libs.interval import Interval
from pandas._libs.tslibs import NaT, Period, Timestamp, timezones
from pandas.core.dtypes.generic import ABCCategoricalIndex, ABCDateOffset, ABCIndexClass
from pandas._typing import Ordered
from .base import ExtensionDtype
from .inference import is_bool, is_list_like
str_type = str
# GH26403: sentinel value used for the default value of ordered in the
# CategoricalDtype constructor to detect when ordered=None is explicitly passed
ordered_sentinel = object() # type: object
def register_extension_dtype(cls: Type[ExtensionDtype]) -> Type[ExtensionDtype]:
"""
Register an ExtensionType with pandas as class decorator.
.. versionadded:: 0.24.0
This enables operations like ``.astype(name)`` for the name
of the ExtensionDtype.
Returns
-------
callable
A class decorator.
Examples
--------
>>> from pandas.api.extensions import register_extension_dtype
>>> from pandas.api.extensions import ExtensionDtype
>>> @register_extension_dtype
... class MyExtensionDtype(ExtensionDtype):
... pass
"""
registry.register(cls)
return cls
class Registry:
"""
Registry for dtype inference
The registry allows one to map a string repr of a extension
dtype to an extension dtype. The string alias can be used in several
places, including
* Series and Index constructors
* :meth:`pandas.array`
* :meth:`pandas.Series.astype`
Multiple extension types can be registered.
These are tried in order.
"""
def __init__(self):
self.dtypes = [] # type: List[Type[ExtensionDtype]]
def register(self, dtype: Type[ExtensionDtype]) -> None:
"""
Parameters
----------
dtype : ExtensionDtype
"""
if not issubclass(dtype, ExtensionDtype):
raise ValueError("can only register pandas extension dtypes")
self.dtypes.append(dtype)
def find(
self, dtype: Union[Type[ExtensionDtype], str]
) -> Optional[Type[ExtensionDtype]]:
"""
Parameters
----------
dtype : Type[ExtensionDtype] or string
Returns
-------
return the first matching dtype, otherwise return None
"""
if not isinstance(dtype, str):
dtype_type = dtype
if not isinstance(dtype, type):
dtype_type = type(dtype)
if issubclass(dtype_type, ExtensionDtype):
return dtype
return None
for dtype_type in self.dtypes:
try:
return dtype_type.construct_from_string(dtype)
except TypeError:
pass
return None
registry = Registry()
class PandasExtensionDtype(ExtensionDtype):
"""
A np.dtype duck-typed class, suitable for holding a custom dtype.
THIS IS NOT A REAL NUMPY DTYPE
"""
type = None # type: Any
kind = None # type: Any
# The Any type annotations above are here only because mypy seems to have a
# problem dealing with with multiple inheritance from PandasExtensionDtype
# and ExtensionDtype's @properties in the subclasses below. The kind and
# type variables in those subclasses are explicitly typed below.
subdtype = None
str = None # type: Optional[str_type]
num = 100
shape = tuple() # type: Tuple[int, ...]
itemsize = 8
base = None
isbuiltin = 0
isnative = 0
_cache = {} # type: Dict[str_type, 'PandasExtensionDtype']
def __str__(self) -> str_type:
"""
Return a string representation for a particular Object
"""
return self.name
def __repr__(self) -> str_type:
"""
Return a string representation for a particular object.
"""
return str(self)
def __hash__(self) -> int:
raise NotImplementedError("sub-classes should implement an __hash__ method")
def __getstate__(self) -> Dict[str_type, Any]:
# pickle support; we don't want to pickle the cache
return {k: getattr(self, k, None) for k in self._metadata}
@classmethod
def reset_cache(cls) -> None:
""" clear the cache """
cls._cache = {}
class CategoricalDtypeType(type):
"""
the type of CategoricalDtype, this metaclass determines subclass ability
"""
pass
@register_extension_dtype
class CategoricalDtype(PandasExtensionDtype, ExtensionDtype):
"""
Type for categorical data with the categories and orderedness.
.. versionchanged:: 0.21.0
Parameters
----------
categories : sequence, optional
Must be unique, and must not contain any nulls.
ordered : bool, default False
Attributes
----------
categories
ordered
Methods
-------
None
See Also
--------
Categorical
Notes
-----
This class is useful for specifying the type of a ``Categorical``
independent of the values. See :ref:`categorical.categoricaldtype`
for more.
Examples
--------
>>> t = pd.CategoricalDtype(categories=['b', 'a'], ordered=True)
>>> pd.Series(['a', 'b', 'a', 'c'], dtype=t)
0 a
1 b
2 a
3 NaN
dtype: category
Categories (2, object): [b < a]
"""
# TODO: Document public vs. private API
name = "category"
type = CategoricalDtypeType # type: Type[CategoricalDtypeType]
kind = "O" # type: str_type
str = "|O08"
base = np.dtype("O")
_metadata = ("categories", "ordered", "_ordered_from_sentinel")
_cache = {} # type: Dict[str_type, PandasExtensionDtype]
def __init__(
self, categories=None, ordered: Union[Ordered, object] = ordered_sentinel
):
# TODO(GH26403): Set type of ordered to Ordered
ordered = cast(Ordered, ordered)
self._finalize(categories, ordered, fastpath=False)
@classmethod
def _from_fastpath(
cls, categories=None, ordered: Optional[bool] = None
) -> "CategoricalDtype":
self = cls.__new__(cls)
self._finalize(categories, ordered, fastpath=True)
return self
@classmethod
def _from_categorical_dtype(
cls, dtype: "CategoricalDtype", categories=None, ordered: Ordered = None
) -> "CategoricalDtype":
if categories is ordered is None:
return dtype
if categories is None:
categories = dtype.categories
if ordered is None:
ordered = dtype.ordered
return cls(categories, ordered)
@classmethod
def _from_values_or_dtype(
cls,
values=None,
categories=None,
ordered: Optional[bool] = None,
dtype: Optional["CategoricalDtype"] = None,
) -> "CategoricalDtype":
"""
Construct dtype from the input parameters used in :class:`Categorical`.
This constructor method specifically does not do the factorization
step, if that is needed to find the categories. This constructor may
therefore return ``CategoricalDtype(categories=None, ordered=None)``,
which may not be useful. Additional steps may therefore have to be
taken to create the final dtype.
The return dtype is specified from the inputs in this prioritized
order:
1. if dtype is a CategoricalDtype, return dtype
2. if dtype is the string 'category', create a CategoricalDtype from
the supplied categories and ordered parameters, and return that.
3. if values is a categorical, use value.dtype, but override it with
categories and ordered if either/both of those are not None.
4. if dtype is None and values is not a categorical, construct the
dtype from categories and ordered, even if either of those is None.
Parameters
----------
values : list-like, optional
The list-like must be 1-dimensional.
categories : list-like, optional
Categories for the CategoricalDtype.
ordered : bool, optional
Designating if the categories are ordered.
dtype : CategoricalDtype or the string "category", optional
If ``CategoricalDtype``, cannot be used together with
`categories` or `ordered`.
Returns
-------
CategoricalDtype
Examples
--------
>>> CategoricalDtype._from_values_or_dtype()
CategoricalDtype(categories=None, ordered=None)
>>> CategoricalDtype._from_values_or_dtype(categories=['a', 'b'],
... ordered=True)
CategoricalDtype(categories=['a', 'b'], ordered=True)
>>> dtype1 = CategoricalDtype(['a', 'b'], ordered=True)
>>> dtype2 = CategoricalDtype(['x', 'y'], ordered=False)
>>> c = Categorical([0, 1], dtype=dtype1, fastpath=True)
>>> CategoricalDtype._from_values_or_dtype(c, ['x', 'y'], ordered=True,
... dtype=dtype2)
ValueError: Cannot specify `categories` or `ordered` together with
`dtype`.
The supplied dtype takes precedence over values' dtype:
>>> CategoricalDtype._from_values_or_dtype(c, dtype=dtype2)
CategoricalDtype(['x', 'y'], ordered=False)
"""
from pandas.core.dtypes.common import is_categorical
if dtype is not None:
# The dtype argument takes precedence over values.dtype (if any)
if isinstance(dtype, str):
if dtype == "category":
dtype = CategoricalDtype(categories, ordered)
else:
msg = "Unknown dtype {dtype!r}"
raise ValueError(msg.format(dtype=dtype))
elif categories is not None or ordered is not None:
raise ValueError(
"Cannot specify `categories` or `ordered` together with `dtype`."
)
elif is_categorical(values):
# If no "dtype" was passed, use the one from "values", but honor
# the "ordered" and "categories" arguments
dtype = values.dtype._from_categorical_dtype(
values.dtype, categories, ordered
)
else:
# If dtype=None and values is not categorical, create a new dtype.
# Note: This could potentially have categories=None and
# ordered=None.
dtype = CategoricalDtype(categories, ordered)
return dtype
def _finalize(self, categories, ordered: Ordered, fastpath: bool = False) -> None:
if ordered is not None and ordered is not ordered_sentinel:
self.validate_ordered(ordered)
if categories is not None:
categories = self.validate_categories(categories, fastpath=fastpath)
self._categories = categories
self._ordered = ordered if ordered is not ordered_sentinel else None
self._ordered_from_sentinel = ordered is ordered_sentinel
def __setstate__(self, state: Dict[str_type, Any]) -> None:
# for pickle compat. __get_state__ is defined in the
# PandasExtensionDtype superclass and uses the public properties to
# pickle -> need to set the settable private ones here (see GH26067)
self._categories = state.pop("categories", None)
self._ordered = state.pop("ordered", False)
self._ordered_from_sentinel = state.pop("_ordered_from_sentinel", False)
def __hash__(self) -> int:
# _hash_categories returns a uint64, so use the negative
# space for when we have unknown categories to avoid a conflict
if self.categories is None:
if self._ordered:
return -1
else:
return -2
# We *do* want to include the real self.ordered here
return int(self._hash_categories(self.categories, self._ordered))
def __eq__(self, other: Any) -> bool:
"""
Rules for CDT equality:
1) Any CDT is equal to the string 'category'
2) Any CDT is equal to itself
3) Any CDT is equal to a CDT with categories=None regardless of ordered
4) A CDT with ordered=True is only equal to another CDT with
ordered=True and identical categories in the same order
5) A CDT with ordered={False, None} is only equal to another CDT with
ordered={False, None} and identical categories, but same order is
not required. There is no distinction between False/None.
6) Any other comparison returns False
"""
if isinstance(other, str):
return other == self.name
elif other is self:
return True
elif not (hasattr(other, "_ordered") and hasattr(other, "categories")):
return False
elif self.categories is None or other.categories is None:
# We're forced into a suboptimal corner thanks to math and
# backwards compatibility. We require that `CDT(...) == 'category'`
# for all CDTs **including** `CDT(None, ...)`. Therefore, *all*
# CDT(., .) = CDT(None, False) and *all*
# CDT(., .) = CDT(None, True).
return True
elif self._ordered or other._ordered:
# At least one has ordered=True; equal if both have ordered=True
# and the same values for categories in the same order.
return (self._ordered == other._ordered) and self.categories.equals(
other.categories
)
else:
# Neither has ordered=True; equal if both have the same categories,
# but same order is not necessary. There is no distinction between
# ordered=False and ordered=None: CDT(., False) and CDT(., None)
# will be equal if they have the same categories.
if (
self.categories.dtype == other.categories.dtype
and self.categories.equals(other.categories)
):
# Check and see if they happen to be identical categories
return True
return hash(self) == hash(other)
def __repr__(self):
tpl = "CategoricalDtype(categories={}ordered={})"
if self.categories is None:
data = "None, "
else:
data = self.categories._format_data(name=self.__class__.__name__)
return tpl.format(data, self._ordered)
@staticmethod
def _hash_categories(categories, ordered: Ordered = True) -> int:
from pandas.core.util.hashing import (
hash_array,
_combine_hash_arrays,
hash_tuples,
)
from pandas.core.dtypes.common import is_datetime64tz_dtype, _NS_DTYPE
if len(categories) and isinstance(categories[0], tuple):
# assumes if any individual category is a tuple, then all our. ATM
# I don't really want to support just some of the categories being
# tuples.
categories = list(categories) # breaks if a np.array of categories
cat_array = hash_tuples(categories)
else:
if categories.dtype == "O":
if len({type(x) for x in categories}) != 1:
# TODO: hash_array doesn't handle mixed types. It casts
# everything to a str first, which means we treat
# {'1', '2'} the same as {'1', 2}
# find a better solution
hashed = hash((tuple(categories), ordered))
return hashed
if is_datetime64tz_dtype(categories.dtype):
# Avoid future warning.
categories = categories.astype(_NS_DTYPE)
cat_array = hash_array(np.asarray(categories), categorize=False)
if ordered:
cat_array = np.vstack(
[cat_array, np.arange(len(cat_array), dtype=cat_array.dtype)]
)
else:
cat_array = [cat_array]
hashed = _combine_hash_arrays(iter(cat_array), num_items=len(cat_array))
return np.bitwise_xor.reduce(hashed)
@classmethod
def construct_array_type(cls):
"""
Return the array type associated with this dtype
Returns
-------
type
"""
from pandas import Categorical
return Categorical
@staticmethod
def validate_ordered(ordered: Ordered) -> None:
"""
Validates that we have a valid ordered parameter. If
it is not a boolean, a TypeError will be raised.
Parameters
----------
ordered : object
The parameter to be verified.
Raises
------
TypeError
If 'ordered' is not a boolean.
"""
if not is_bool(ordered):
raise TypeError("'ordered' must either be 'True' or 'False'")
@staticmethod
def validate_categories(categories, fastpath: bool = False):
"""
Validates that we have good categories
Parameters
----------
categories : array-like
fastpath : bool
Whether to skip nan and uniqueness checks
Returns
-------
categories : Index
"""
from pandas.core.indexes.base import Index
if not fastpath and not is_list_like(categories):
msg = "Parameter 'categories' must be list-like, was {!r}"
raise TypeError(msg.format(categories))
elif not isinstance(categories, ABCIndexClass):
categories = Index(categories, tupleize_cols=False)
if not fastpath:
if categories.hasnans:
raise ValueError("Categorial categories cannot be null")
if not categories.is_unique:
raise ValueError("Categorical categories must be unique")
if isinstance(categories, ABCCategoricalIndex):
categories = categories.categories
return categories
def update_dtype(
self, dtype: Union[str_type, "CategoricalDtype"]
) -> "CategoricalDtype":
"""
Returns a CategoricalDtype with categories and ordered taken from dtype
if specified, otherwise falling back to self if unspecified
Parameters
----------
dtype : CategoricalDtype
Returns
-------
new_dtype : CategoricalDtype
"""
if isinstance(dtype, str) and dtype == "category":
# dtype='category' should not change anything
return self
elif not self.is_dtype(dtype):
msg = (
"a CategoricalDtype must be passed to perform an update, "
"got {dtype!r}"
).format(dtype=dtype)
raise ValueError(msg)
else:
# from here on, dtype is a CategoricalDtype
dtype = cast(CategoricalDtype, dtype)
# dtype is CDT: keep current categories/ordered if None
new_categories = dtype.categories
if new_categories is None:
new_categories = self.categories
new_ordered = dtype._ordered
new_ordered_from_sentinel = dtype._ordered_from_sentinel
if new_ordered is None:
# maintain existing ordered if new dtype has ordered=None
new_ordered = self._ordered
if self._ordered and new_ordered_from_sentinel:
# only warn if we'd actually change the existing behavior
msg = (
"Constructing a CategoricalDtype without specifying "
"`ordered` will default to `ordered=False` in a future "
"version, which will cause the resulting categorical's "
"`ordered` attribute to change to False; `ordered=True`"
" must be explicitly passed in order to be retained"
)
warnings.warn(msg, FutureWarning, stacklevel=3)
return CategoricalDtype(new_categories, new_ordered)
@property
def categories(self):
"""
An ``Index`` containing the unique categories allowed.
"""
return self._categories
@property
def ordered(self) -> Ordered:
"""
Whether the categories have an ordered relationship.
"""
# TODO: remove if block when ordered=None as default is deprecated
if self._ordered_from_sentinel and self._ordered is None:
# warn when accessing ordered if ordered=None and None was not
# explicitly passed to the constructor
msg = (
"Constructing a CategoricalDtype without specifying "
"`ordered` will default to `ordered=False` in a future "
"version; `ordered=None` must be explicitly passed."
)
warnings.warn(msg, FutureWarning, stacklevel=2)
return self._ordered
@property
def _is_boolean(self) -> bool:
from pandas.core.dtypes.common import is_bool_dtype
return is_bool_dtype(self.categories)
@register_extension_dtype
class DatetimeTZDtype(PandasExtensionDtype):
"""
An ExtensionDtype for timezone-aware datetime data.
**This is not an actual numpy dtype**, but a duck type.
Parameters
----------
unit : str, default "ns"
The precision of the datetime data. Currently limited
to ``"ns"``.
tz : str, int, or datetime.tzinfo
The timezone.
Attributes
----------
unit
tz
Methods
-------
None
Raises
------
pytz.UnknownTimeZoneError
When the requested timezone cannot be found.
Examples
--------
>>> pd.DatetimeTZDtype(tz='UTC')
datetime64[ns, UTC]
>>> pd.DatetimeTZDtype(tz='dateutil/US/Central')
datetime64[ns, tzfile('/usr/share/zoneinfo/US/Central')]
"""
type = Timestamp # type: Type[Timestamp]
kind = "M" # type: str_type
str = "|M8[ns]"
num = 101
base = np.dtype("M8[ns]")
na_value = NaT
_metadata = ("unit", "tz")
_match = re.compile(r"(datetime64|M8)\[(?P<unit>.+), (?P<tz>.+)\]")
_cache = {} # type: Dict[str_type, PandasExtensionDtype]
def __init__(self, unit="ns", tz=None):
if isinstance(unit, DatetimeTZDtype):
unit, tz = unit.unit, unit.tz
if unit != "ns":
if isinstance(unit, str) and tz is None:
# maybe a string like datetime64[ns, tz], which we support for
# now.
result = type(self).construct_from_string(unit)
unit = result.unit
tz = result.tz
msg = (
"Passing a dtype alias like 'datetime64[ns, {tz}]' "
"to DatetimeTZDtype is deprecated. Use "
"'DatetimeTZDtype.construct_from_string()' instead."
)
warnings.warn(msg.format(tz=tz), FutureWarning, stacklevel=2)
else:
raise ValueError("DatetimeTZDtype only supports ns units")
if tz:
tz = timezones.maybe_get_tz(tz)
tz = timezones.tz_standardize(tz)
elif tz is not None:
raise pytz.UnknownTimeZoneError(tz)
if tz is None:
raise TypeError("A 'tz' is required.")
self._unit = unit
self._tz = tz
@property
def unit(self):
"""
The precision of the datetime data.
"""
return self._unit
@property
def tz(self):
"""
The timezone.
"""
return self._tz
@classmethod
def construct_array_type(cls):
"""
Return the array type associated with this dtype
Returns
-------
type
"""
from pandas.core.arrays import DatetimeArray
return DatetimeArray
@classmethod
def construct_from_string(cls, string):
"""
Construct a DatetimeTZDtype from a string.
Parameters
----------
string : str
The string alias for this DatetimeTZDtype.
Should be formatted like ``datetime64[ns, <tz>]``,
where ``<tz>`` is the timezone name.
Examples
--------
>>> DatetimeTZDtype.construct_from_string('datetime64[ns, UTC]')
datetime64[ns, UTC]
"""
if isinstance(string, str):
msg = "Could not construct DatetimeTZDtype from '{}'"
match = cls._match.match(string)
if match:
d = match.groupdict()
try:
return cls(unit=d["unit"], tz=d["tz"])
except (KeyError, TypeError, ValueError) as err:
# KeyError if maybe_get_tz tries and fails to get a
# pytz timezone (actually pytz.UnknownTimeZoneError).
# TypeError if we pass a nonsense tz;
# ValueError if we pass a unit other than "ns"
raise TypeError(msg.format(string)) from err
raise TypeError(msg.format(string))
raise TypeError("Could not construct DatetimeTZDtype")
def __str__(self):
return "datetime64[{unit}, {tz}]".format(unit=self.unit, tz=self.tz)
@property
def name(self):
"""A string representation of the dtype."""
return str(self)
def __hash__(self):
# make myself hashable
# TODO: update this.
return hash(str(self))
def __eq__(self, other):
if isinstance(other, str):
return other == self.name
return (
isinstance(other, DatetimeTZDtype)
and self.unit == other.unit
and str(self.tz) == str(other.tz)
)
def __setstate__(self, state):
# for pickle compat. __get_state__ is defined in the
# PandasExtensionDtype superclass and uses the public properties to
# pickle -> need to set the settable private ones here (see GH26067)
self._tz = state["tz"]
self._unit = state["unit"]
@register_extension_dtype
class PeriodDtype(PandasExtensionDtype):
"""
An ExtensionDtype for Period data.
**This is not an actual numpy dtype**, but a duck type.
Parameters
----------
freq : str or DateOffset
The frequency of this PeriodDtype
Attributes
----------
freq
Methods
-------
None
Examples
--------
>>> pd.PeriodDtype(freq='D')
period[D]
>>> pd.PeriodDtype(freq=pd.offsets.MonthEnd())
period[M]
"""
type = Period # type: Type[Period]
kind = "O" # type: str_type
str = "|O08"
base = np.dtype("O")
num = 102
_metadata = ("freq",)
_match = re.compile(r"(P|p)eriod\[(?P<freq>.+)\]")
_cache = {} # type: Dict[str_type, PandasExtensionDtype]
def __new__(cls, freq=None):
"""
Parameters
----------
freq : frequency
"""
if isinstance(freq, PeriodDtype):
return freq
elif freq is None:
# empty constructor for pickle compat
u = object.__new__(cls)
u._freq = None
return u
if not isinstance(freq, ABCDateOffset):
freq = cls._parse_dtype_strict(freq)
try:
return cls._cache[freq.freqstr]
except KeyError:
u = object.__new__(cls)
u._freq = freq
cls._cache[freq.freqstr] = u
return u
@property
def freq(self):
"""
The frequency object of this PeriodDtype.
"""
return self._freq
@classmethod
def _parse_dtype_strict(cls, freq):
if isinstance(freq, str):
if freq.startswith("period[") or freq.startswith("Period["):
m = cls._match.search(freq)
if m is not None:
freq = m.group("freq")
from pandas.tseries.frequencies import to_offset
freq = to_offset(freq)
if freq is not None:
return freq
raise ValueError("could not construct PeriodDtype")
@classmethod
def construct_from_string(cls, string):
"""
Strict construction from a string, raise a TypeError if not
possible
"""
if (
isinstance(string, str)
and (string.startswith("period[") or string.startswith("Period["))
or isinstance(string, ABCDateOffset)
):
# do not parse string like U as period[U]
# avoid tuple to be regarded as freq
try:
return cls(freq=string)
except ValueError:
pass
raise TypeError("could not construct PeriodDtype")
def __str__(self):
return self.name
@property
def name(self):
return "period[{freq}]".format(freq=self.freq.freqstr)
@property
def na_value(self):
return NaT
def __hash__(self):
# make myself hashable
return hash(str(self))
def __eq__(self, other):
if isinstance(other, str):
return other == self.name or other == self.name.title()
return isinstance(other, PeriodDtype) and self.freq == other.freq
def __setstate__(self, state):
# for pickle compat. __get_state__ is defined in the
# PandasExtensionDtype superclass and uses the public properties to
# pickle -> need to set the settable private ones here (see GH26067)
self._freq = state["freq"]
@classmethod
def is_dtype(cls, dtype):
"""
Return a boolean if we if the passed type is an actual dtype that we
can match (via string or type)
"""
if isinstance(dtype, str):
# PeriodDtype can be instantiated from freq string like "U",
# but doesn't regard freq str like "U" as dtype.
if dtype.startswith("period[") or dtype.startswith("Period["):
try:
if cls._parse_dtype_strict(dtype) is not None:
return True
else:
return False
except ValueError:
return False
else:
return False
return super().is_dtype(dtype)
@classmethod
def construct_array_type(cls):
from pandas.core.arrays import PeriodArray
return PeriodArray
@register_extension_dtype
class IntervalDtype(PandasExtensionDtype):
"""
An ExtensionDtype for Interval data.
**This is not an actual numpy dtype**, but a duck type.
Parameters
----------
subtype : str, np.dtype
The dtype of the Interval bounds.
Attributes
----------
subtype
Methods
-------
None
Examples
--------
>>> pd.IntervalDtype(subtype='int64')
interval[int64]
"""
name = "interval"
kind = None # type: Optional[str_type]
str = "|O08"
base = np.dtype("O")
num = 103
_metadata = ("subtype",)
_match = re.compile(r"(I|i)nterval\[(?P<subtype>.+)\]")
_cache = {} # type: Dict[str_type, PandasExtensionDtype]
def __new__(cls, subtype=None):
from pandas.core.dtypes.common import (
is_categorical_dtype,
is_string_dtype,
pandas_dtype,
)
if isinstance(subtype, IntervalDtype):
return subtype
elif subtype is None:
# we are called as an empty constructor
# generally for pickle compat
u = object.__new__(cls)
u._subtype = None
return u
elif isinstance(subtype, str) and subtype.lower() == "interval":
subtype = None
else:
if isinstance(subtype, str):
m = cls._match.search(subtype)
if m is not None:
subtype = m.group("subtype")
try:
subtype = pandas_dtype(subtype)
except TypeError:
raise TypeError("could not construct IntervalDtype")
if is_categorical_dtype(subtype) or is_string_dtype(subtype):
# GH 19016
msg = (
"category, object, and string subtypes are not supported "
"for IntervalDtype"
)
raise TypeError(msg)
try:
return cls._cache[str(subtype)]
except KeyError:
u = object.__new__(cls)
u._subtype = subtype
cls._cache[str(subtype)] = u
return u
@property
def subtype(self):
"""
The dtype of the Interval bounds.
"""
return self._subtype
@classmethod
def construct_array_type(cls):
"""
Return the array type associated with this dtype
Returns
-------
type
"""
from pandas.core.arrays import IntervalArray
return IntervalArray
@classmethod
def construct_from_string(cls, string):
"""
attempt to construct this type from a string, raise a TypeError
if its not possible
"""
if not isinstance(string, str):
msg = "a string needs to be passed, got type {typ}"
raise TypeError(msg.format(typ=type(string)))
if string.lower() == "interval" or cls._match.search(string) is not None:
return cls(string)
msg = (
"Incorrectly formatted string passed to constructor. "
"Valid formats include Interval or Interval[dtype] "
"where dtype is numeric, datetime, or timedelta"
)
raise TypeError(msg)
@property
def type(self):
return Interval
def __str__(self):
if self.subtype is None:
return "interval"
return "interval[{subtype}]".format(subtype=self.subtype)
def __hash__(self):
# make myself hashable
return hash(str(self))
def __eq__(self, other):
if isinstance(other, str):
return other.lower() in (self.name.lower(), str(self).lower())
elif not isinstance(other, IntervalDtype):
return False
elif self.subtype is None or other.subtype is None:
# None should match any subtype
return True
else:
from pandas.core.dtypes.common import is_dtype_equal
return is_dtype_equal(self.subtype, other.subtype)
def __setstate__(self, state):
# for pickle compat. __get_state__ is defined in the
# PandasExtensionDtype superclass and uses the public properties to
# pickle -> need to set the settable private ones here (see GH26067)
self._subtype = state["subtype"]
@classmethod
def is_dtype(cls, dtype):
"""
Return a boolean if we if the passed type is an actual dtype that we
can match (via string or type)
"""
if isinstance(dtype, str):
if dtype.lower().startswith("interval"):
try:
if cls.construct_from_string(dtype) is not None:
return True
else:
return False
except (ValueError, TypeError):
return False
else:
return False
return super().is_dtype(dtype)
| BugsInPy/BugsInPy/temp/projects/pandas/bug-147-fixed/pandas/pandas/core/dtypes/dtypes.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-147-buggy/pandas/pandas/core/dtypes/dtypes.py |
pandas-bug-41 | from datetime import datetime, timedelta
import functools
import inspect
import re
from typing import Any, List
import warnings
import numpy as np
from pandas._libs import NaT, Timestamp, algos as libalgos, lib, tslib, writers
import pandas._libs.internals as libinternals
from pandas._libs.tslibs import Timedelta, conversion
from pandas._libs.tslibs.timezones import tz_compare
from pandas.util._validators import validate_bool_kwarg
from pandas.core.dtypes.cast import (
astype_nansafe,
convert_scalar_for_putitemlike,
find_common_type,
infer_dtype_from,
infer_dtype_from_scalar,
maybe_downcast_numeric,
maybe_downcast_to_dtype,
maybe_infer_dtype_type,
maybe_promote,
maybe_upcast,
soft_convert_objects,
)
from pandas.core.dtypes.common import (
_NS_DTYPE,
_TD_DTYPE,
is_bool_dtype,
is_categorical,
is_categorical_dtype,
is_datetime64_dtype,
is_datetime64tz_dtype,
is_dtype_equal,
is_extension_array_dtype,
is_float_dtype,
is_integer,
is_integer_dtype,
is_interval_dtype,
is_list_like,
is_object_dtype,
is_period_dtype,
is_re,
is_re_compilable,
is_sparse,
is_timedelta64_dtype,
pandas_dtype,
)
from pandas.core.dtypes.concat import concat_categorical, concat_datetime
from pandas.core.dtypes.dtypes import CategoricalDtype, ExtensionDtype
from pandas.core.dtypes.generic import (
ABCDataFrame,
ABCExtensionArray,
ABCPandasArray,
ABCSeries,
)
from pandas.core.dtypes.missing import (
_isna_compat,
array_equivalent,
is_valid_nat_for_dtype,
isna,
)
import pandas.core.algorithms as algos
from pandas.core.array_algos.transforms import shift
from pandas.core.arrays import (
Categorical,
DatetimeArray,
ExtensionArray,
PandasArray,
PandasDtype,
TimedeltaArray,
)
from pandas.core.base import PandasObject
import pandas.core.common as com
from pandas.core.construction import extract_array
from pandas.core.indexers import (
check_setitem_lengths,
is_empty_indexer,
is_scalar_indexer,
)
import pandas.core.missing as missing
from pandas.core.nanops import nanpercentile
class Block(PandasObject):
"""
Canonical n-dimensional unit of homogeneous dtype contained in a pandas
data structure
Index-ignorant; let the container take care of that
"""
__slots__ = ["_mgr_locs", "values", "ndim"]
is_numeric = False
is_float = False
is_integer = False
is_complex = False
is_datetime = False
is_datetimetz = False
is_timedelta = False
is_bool = False
is_object = False
is_categorical = False
is_extension = False
_can_hold_na = False
_can_consolidate = True
_verify_integrity = True
_validate_ndim = True
_concatenator = staticmethod(np.concatenate)
def __init__(self, values, placement, ndim=None):
self.ndim = self._check_ndim(values, ndim)
self.mgr_locs = placement
self.values = values
if self._validate_ndim and self.ndim and len(self.mgr_locs) != len(self.values):
raise ValueError(
f"Wrong number of items passed {len(self.values)}, "
f"placement implies {len(self.mgr_locs)}"
)
def _check_ndim(self, values, ndim):
"""
ndim inference and validation.
Infers ndim from 'values' if not provided to __init__.
Validates that values.ndim and ndim are consistent if and only if
the class variable '_validate_ndim' is True.
Parameters
----------
values : array-like
ndim : int or None
Returns
-------
ndim : int
Raises
------
ValueError : the number of dimensions do not match
"""
if ndim is None:
ndim = values.ndim
if self._validate_ndim and values.ndim != ndim:
raise ValueError(
"Wrong number of dimensions. "
f"values.ndim != ndim [{values.ndim} != {ndim}]"
)
return ndim
@property
def _holder(self):
"""
The array-like that can hold the underlying values.
None for 'Block', overridden by subclasses that don't
use an ndarray.
"""
return None
@property
def _consolidate_key(self):
return (self._can_consolidate, self.dtype.name)
@property
def _is_single_block(self) -> bool:
return self.ndim == 1
@property
def is_view(self) -> bool:
""" return a boolean if I am possibly a view """
return self.values.base is not None
@property
def is_datelike(self) -> bool:
""" return True if I am a non-datelike """
return self.is_datetime or self.is_timedelta
def is_categorical_astype(self, dtype) -> bool:
"""
validate that we have a astypeable to categorical,
returns a boolean if we are a categorical
"""
if dtype is Categorical or dtype is CategoricalDtype:
# this is a pd.Categorical, but is not
# a valid type for astypeing
raise TypeError(f"invalid type {dtype} for astype")
elif is_categorical_dtype(dtype):
return True
return False
def external_values(self):
"""
The array that Series.values returns (public attribute).
This has some historical constraints, and is overridden in block
subclasses to return the correct array (e.g. period returns
object ndarray and datetimetz a datetime64[ns] ndarray instead of
proper extension array).
"""
return self.values
def internal_values(self):
"""
The array that Series._values returns (internal values).
"""
return self.values
def array_values(self) -> ExtensionArray:
"""
The array that Series.array returns. Always an ExtensionArray.
"""
return PandasArray(self.values)
def get_values(self, dtype=None):
"""
return an internal format, currently just the ndarray
this is often overridden to handle to_dense like operations
"""
if is_object_dtype(dtype):
return self.values.astype(object)
return self.values
def get_block_values_for_json(self) -> np.ndarray:
"""
This is used in the JSON C code.
"""
# TODO(2DEA): reshape will be unnecessary with 2D EAs
return np.asarray(self.values).reshape(self.shape)
@property
def fill_value(self):
return np.nan
@property
def mgr_locs(self):
return self._mgr_locs
@mgr_locs.setter
def mgr_locs(self, new_mgr_locs):
if not isinstance(new_mgr_locs, libinternals.BlockPlacement):
new_mgr_locs = libinternals.BlockPlacement(new_mgr_locs)
self._mgr_locs = new_mgr_locs
def make_block(self, values, placement=None) -> "Block":
"""
Create a new block, with type inference propagate any values that are
not specified
"""
if placement is None:
placement = self.mgr_locs
return make_block(values, placement=placement, ndim=self.ndim)
def make_block_same_class(self, values, placement=None, ndim=None):
""" Wrap given values in a block of same type as self. """
if placement is None:
placement = self.mgr_locs
if ndim is None:
ndim = self.ndim
return make_block(values, placement=placement, ndim=ndim, klass=type(self))
def __repr__(self) -> str:
# don't want to print out all of the items here
name = type(self).__name__
if self._is_single_block:
result = f"{name}: {len(self)} dtype: {self.dtype}"
else:
shape = " x ".join(str(s) for s in self.shape)
result = f"{name}: {self.mgr_locs.indexer}, {shape}, dtype: {self.dtype}"
return result
def __len__(self) -> int:
return len(self.values)
def __getstate__(self):
return self.mgr_locs.indexer, self.values
def __setstate__(self, state):
self.mgr_locs = libinternals.BlockPlacement(state[0])
self.values = state[1]
self.ndim = self.values.ndim
def _slice(self, slicer):
""" return a slice of my values """
return self.values[slicer]
def getitem_block(self, slicer, new_mgr_locs=None):
"""
Perform __getitem__-like, return result as block.
As of now, only supports slices that preserve dimensionality.
"""
if new_mgr_locs is None:
axis0_slicer = slicer[0] if isinstance(slicer, tuple) else slicer
new_mgr_locs = self.mgr_locs[axis0_slicer]
new_values = self._slice(slicer)
if self._validate_ndim and new_values.ndim != self.ndim:
raise ValueError("Only same dim slicing is allowed")
return self.make_block_same_class(new_values, new_mgr_locs)
@property
def shape(self):
return self.values.shape
@property
def dtype(self):
return self.values.dtype
def merge(self, other):
return _merge_blocks([self, other])
def concat_same_type(self, to_concat, placement=None):
"""
Concatenate list of single blocks of the same type.
"""
values = self._concatenator(
[blk.values for blk in to_concat], axis=self.ndim - 1
)
return self.make_block_same_class(
values, placement=placement or slice(0, len(values), 1)
)
def iget(self, i):
return self.values[i]
def set(self, locs, values):
"""
Modify Block in-place with new item value
Returns
-------
None
"""
self.values[locs] = values
def delete(self, loc) -> None:
"""
Delete given loc(-s) from block in-place.
"""
self.values = np.delete(self.values, loc, 0)
self.mgr_locs = self.mgr_locs.delete(loc)
def apply(self, func, **kwargs) -> List["Block"]:
"""
apply the function to my values; return a block if we are not
one
"""
with np.errstate(all="ignore"):
result = func(self.values, **kwargs)
return self._split_op_result(result)
def _split_op_result(self, result) -> List["Block"]:
# See also: split_and_operate
if is_extension_array_dtype(result) and result.ndim > 1:
# if we get a 2D ExtensionArray, we need to split it into 1D pieces
nbs = []
for i, loc in enumerate(self.mgr_locs):
vals = result[i]
nv = _block_shape(vals, ndim=self.ndim)
block = self.make_block(values=nv, placement=[loc])
nbs.append(block)
return nbs
if not isinstance(result, Block):
result = self.make_block(values=_block_shape(result, ndim=self.ndim))
return [result]
def fillna(
self, value, limit=None, inplace: bool = False, downcast=None
) -> List["Block"]:
"""
fillna on the block with the value. If we fail, then convert to
ObjectBlock and try again
"""
inplace = validate_bool_kwarg(inplace, "inplace")
mask = isna(self.values)
if limit is not None:
limit = libalgos._validate_limit(None, limit=limit)
mask[mask.cumsum(self.ndim - 1) > limit] = False
if not self._can_hold_na:
if inplace:
return [self]
else:
return [self.copy()]
if self._can_hold_element(value):
# equivalent: _try_coerce_args(value) would not raise
blocks = self.putmask(mask, value, inplace=inplace)
return self._maybe_downcast(blocks, downcast)
# we can't process the value, but nothing to do
if not mask.any():
return [self] if inplace else [self.copy()]
# operate column-by-column
def f(mask, val, idx):
block = self.coerce_to_target_dtype(value)
# slice out our block
if idx is not None:
# i.e. self.ndim == 2
block = block.getitem_block(slice(idx, idx + 1))
return block.fillna(value, limit=limit, inplace=inplace, downcast=None)
return self.split_and_operate(None, f, inplace)
def split_and_operate(self, mask, f, inplace: bool) -> List["Block"]:
"""
split the block per-column, and apply the callable f
per-column, return a new block for each. Handle
masking which will not change a block unless needed.
Parameters
----------
mask : 2-d boolean mask
f : callable accepting (1d-mask, 1d values, indexer)
inplace : boolean
Returns
-------
list of blocks
"""
if mask is None:
mask = np.broadcast_to(True, shape=self.shape)
new_values = self.values
def make_a_block(nv, ref_loc):
if isinstance(nv, list):
assert len(nv) == 1, nv
assert isinstance(nv[0], Block)
block = nv[0]
else:
# Put back the dimension that was taken from it and make
# a block out of the result.
nv = _block_shape(nv, ndim=self.ndim)
block = self.make_block(values=nv, placement=ref_loc)
return block
# ndim == 1
if self.ndim == 1:
if mask.any():
nv = f(mask, new_values, None)
else:
nv = new_values if inplace else new_values.copy()
block = make_a_block(nv, self.mgr_locs)
return [block]
# ndim > 1
new_blocks = []
for i, ref_loc in enumerate(self.mgr_locs):
m = mask[i]
v = new_values[i]
# need a new block
if m.any():
nv = f(m, v, i)
else:
nv = v if inplace else v.copy()
block = make_a_block(nv, [ref_loc])
new_blocks.append(block)
return new_blocks
def _maybe_downcast(self, blocks: List["Block"], downcast=None) -> List["Block"]:
# no need to downcast our float
# unless indicated
if downcast is None and (
self.is_float or self.is_timedelta or self.is_datetime
):
return blocks
return _extend_blocks([b.downcast(downcast) for b in blocks])
def downcast(self, dtypes=None):
""" try to downcast each item to the dict of dtypes if present """
# turn it off completely
if dtypes is False:
return self
values = self.values
# single block handling
if self._is_single_block:
# try to cast all non-floats here
if dtypes is None:
dtypes = "infer"
nv = maybe_downcast_to_dtype(values, dtypes)
return self.make_block(nv)
# ndim > 1
if dtypes is None:
return self
if not (dtypes == "infer" or isinstance(dtypes, dict)):
raise ValueError(
"downcast must have a dictionary or 'infer' as its argument"
)
elif dtypes != "infer":
raise AssertionError("dtypes as dict is not supported yet")
# operate column-by-column
# this is expensive as it splits the blocks items-by-item
def f(mask, val, idx):
val = maybe_downcast_to_dtype(val, dtype="infer")
return val
return self.split_and_operate(None, f, False)
def astype(self, dtype, copy: bool = False, errors: str = "raise"):
"""
Coerce to the new dtype.
Parameters
----------
dtype : str, dtype convertible
copy : bool, default False
copy if indicated
errors : str, {'raise', 'ignore'}, default 'ignore'
- ``raise`` : allow exceptions to be raised
- ``ignore`` : suppress exceptions. On error return original object
Returns
-------
Block
"""
errors_legal_values = ("raise", "ignore")
if errors not in errors_legal_values:
invalid_arg = (
"Expected value of kwarg 'errors' to be one of "
f"{list(errors_legal_values)}. Supplied value is '{errors}'"
)
raise ValueError(invalid_arg)
if inspect.isclass(dtype) and issubclass(dtype, ExtensionDtype):
msg = (
f"Expected an instance of {dtype.__name__}, "
"but got the class instead. Try instantiating 'dtype'."
)
raise TypeError(msg)
# may need to convert to categorical
if self.is_categorical_astype(dtype):
if is_categorical_dtype(self.values):
# GH 10696/18593: update an existing categorical efficiently
return self.make_block(self.values.astype(dtype, copy=copy))
return self.make_block(Categorical(self.values, dtype=dtype))
dtype = pandas_dtype(dtype)
# astype processing
if is_dtype_equal(self.dtype, dtype):
if copy:
return self.copy()
return self
# force the copy here
if self.is_extension:
# TODO: Should we try/except this astype?
values = self.values.astype(dtype)
else:
if issubclass(dtype.type, str):
# use native type formatting for datetime/tz/timedelta
if self.is_datelike:
values = self.to_native_types()
# astype formatting
else:
# Because we have neither is_extension nor is_datelike,
# self.values already has the correct shape
values = self.values
else:
values = self.get_values(dtype=dtype)
# _astype_nansafe works fine with 1-d only
vals1d = values.ravel()
try:
values = astype_nansafe(vals1d, dtype, copy=True)
except (ValueError, TypeError):
# e.g. astype_nansafe can fail on object-dtype of strings
# trying to convert to float
if errors == "raise":
raise
newb = self.copy() if copy else self
return newb
# TODO(extension)
# should we make this attribute?
if isinstance(values, np.ndarray):
values = values.reshape(self.shape)
newb = make_block(values, placement=self.mgr_locs, ndim=self.ndim)
if newb.is_numeric and self.is_numeric:
if newb.shape != self.shape:
raise TypeError(
f"cannot set astype for copy = [{copy}] for dtype "
f"({self.dtype.name} [{self.shape}]) to different shape "
f"({newb.dtype.name} [{newb.shape}])"
)
return newb
def convert(
self,
copy: bool = True,
datetime: bool = True,
numeric: bool = True,
timedelta: bool = True,
coerce: bool = False,
):
"""
attempt to coerce any object types to better types return a copy
of the block (if copy = True) by definition we are not an ObjectBlock
here!
"""
return self.copy() if copy else self
def _can_hold_element(self, element: Any) -> bool:
""" require the same dtype as ourselves """
dtype = self.values.dtype.type
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return issubclass(tipo.type, dtype)
return isinstance(element, dtype)
def to_native_types(self, slicer=None, na_rep="nan", quoting=None, **kwargs):
""" convert to our native types format, slicing if desired """
values = self.values
if slicer is not None:
values = values[:, slicer]
mask = isna(values)
itemsize = writers.word_len(na_rep)
if not self.is_object and not quoting and itemsize:
values = values.astype(str)
if values.dtype.itemsize / np.dtype("U1").itemsize < itemsize:
# enlarge for the na_rep
values = values.astype(f"<U{itemsize}")
else:
values = np.array(values, dtype="object")
values[mask] = na_rep
return values
# block actions #
def copy(self, deep: bool = True):
""" copy constructor """
values = self.values
if deep:
values = values.copy()
return self.make_block_same_class(values, ndim=self.ndim)
def replace(
self,
to_replace,
value,
inplace: bool = False,
filter=None,
regex: bool = False,
convert: bool = True,
):
"""
replace the to_replace value with value, possible to create new
blocks here this is just a call to putmask. regex is not used here.
It is used in ObjectBlocks. It is here for API compatibility.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
original_to_replace = to_replace
# If we cannot replace with own dtype, convert to ObjectBlock and
# retry
if not self._can_hold_element(to_replace):
if not isinstance(to_replace, list):
if inplace:
return [self]
return [self.copy()]
to_replace = [x for x in to_replace if self._can_hold_element(x)]
if not len(to_replace):
# GH#28084 avoid costly checks since we can infer
# that there is nothing to replace in this block
if inplace:
return [self]
return [self.copy()]
if len(to_replace) == 1:
# _can_hold_element checks have reduced this back to the
# scalar case and we can avoid a costly object cast
return self.replace(
to_replace[0],
value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
# GH 22083, TypeError or ValueError occurred within error handling
# causes infinite loop. Cast and retry only if not objectblock.
if is_object_dtype(self):
raise AssertionError
# try again with a compatible block
block = self.astype(object)
return block.replace(
to_replace=to_replace,
value=value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
values = self.values
if lib.is_scalar(to_replace) and isinstance(values, np.ndarray):
# The only non-DatetimeLike class that also has a non-trivial
# try_coerce_args is ObjectBlock, but that overrides replace,
# so does not get here.
to_replace = convert_scalar_for_putitemlike(to_replace, values.dtype)
mask = missing.mask_missing(values, to_replace)
if filter is not None:
filtered_out = ~self.mgr_locs.isin(filter)
mask[filtered_out.nonzero()[0]] = False
if not mask.any():
if inplace:
return [self]
return [self.copy()]
try:
blocks = self.putmask(mask, value, inplace=inplace)
# Note: it is _not_ the case that self._can_hold_element(value)
# is always true at this point. In particular, that can fail
# for:
# "2u" with bool-dtype, float-dtype
# 0.5 with int64-dtype
# np.nan with int64-dtype
except (TypeError, ValueError):
# GH 22083, TypeError or ValueError occurred within error handling
# causes infinite loop. Cast and retry only if not objectblock.
if is_object_dtype(self):
raise
assert not self._can_hold_element(value), value
# try again with a compatible block
block = self.astype(object)
return block.replace(
to_replace=original_to_replace,
value=value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
if convert:
blocks = [b.convert(numeric=False, copy=not inplace) for b in blocks]
return blocks
def _replace_single(self, *args, **kwargs):
""" no-op on a non-ObjectBlock """
return self if kwargs["inplace"] else self.copy()
def setitem(self, indexer, value):
"""
Set the value inplace, returning a a maybe different typed block.
Parameters
----------
indexer : tuple, list-like, array-like, slice
The subset of self.values to set
value : object
The value being set
Returns
-------
Block
Notes
-----
`indexer` is a direct slice/positional indexer. `value` must
be a compatible shape.
"""
transpose = self.ndim == 2
if isinstance(indexer, np.ndarray) and indexer.ndim > self.ndim:
raise ValueError(f"Cannot set values with ndim > {self.ndim}")
# coerce None values, if appropriate
if value is None:
if self.is_numeric:
value = np.nan
# coerce if block dtype can store value
values = self.values
if self._can_hold_element(value):
# We only get here for non-Extension Blocks, so _try_coerce_args
# is only relevant for DatetimeBlock and TimedeltaBlock
if lib.is_scalar(value):
value = convert_scalar_for_putitemlike(value, values.dtype)
else:
# current dtype cannot store value, coerce to common dtype
find_dtype = False
if hasattr(value, "dtype"):
dtype = value.dtype
find_dtype = True
elif lib.is_scalar(value) and not isna(value):
dtype, _ = infer_dtype_from_scalar(value, pandas_dtype=True)
find_dtype = True
if find_dtype:
dtype = find_common_type([values.dtype, dtype])
if not is_dtype_equal(self.dtype, dtype):
b = self.astype(dtype)
return b.setitem(indexer, value)
# value must be storeable at this moment
if is_extension_array_dtype(getattr(value, "dtype", None)):
# We need to be careful not to allow through strings that
# can be parsed to EADtypes
arr_value = value
else:
arr_value = np.array(value)
# cast the values to a type that can hold nan (if necessary)
if not self._can_hold_element(value):
dtype, _ = maybe_promote(arr_value.dtype)
values = values.astype(dtype)
if transpose:
values = values.T
# length checking
check_setitem_lengths(indexer, value, values)
exact_match = (
len(arr_value.shape)
and arr_value.shape[0] == values.shape[0]
and arr_value.size == values.size
)
if is_empty_indexer(indexer, arr_value):
# GH#8669 empty indexers
pass
elif is_scalar_indexer(indexer, self.ndim):
# setting a single element for each dim and with a rhs that could
# be e.g. a list; see GH#6043
values[indexer] = value
elif (
exact_match
and is_categorical_dtype(arr_value.dtype)
and not is_categorical_dtype(values)
):
# GH25495 - If the current dtype is not categorical,
# we need to create a new categorical block
values[indexer] = value
return self.make_block(Categorical(self.values, dtype=arr_value.dtype))
# if we are an exact match (ex-broadcasting),
# then use the resultant dtype
elif exact_match:
# We are setting _all_ of the array's values, so can cast to new dtype
values[indexer] = value
values = values.astype(arr_value.dtype, copy=False)
# set
else:
values[indexer] = value
if transpose:
values = values.T
block = self.make_block(values)
return block
def putmask(
self,
mask,
new,
align: bool = True,
inplace: bool = False,
axis: int = 0,
transpose: bool = False,
):
"""
putmask the data to the block; it is possible that we may create a
new dtype of block
return the resulting block(s)
Parameters
----------
mask : the condition to respect
new : a ndarray/object
align : boolean, perform alignment on other/cond, default is True
inplace : perform inplace modification, default is False
axis : int
transpose : boolean
Set to True if self is stored with axes reversed
Returns
-------
a list of new blocks, the result of the putmask
"""
new_values = self.values if inplace else self.values.copy()
new = getattr(new, "values", new)
mask = getattr(mask, "values", mask)
# if we are passed a scalar None, convert it here
if not is_list_like(new) and isna(new) and not self.is_object:
# FIXME: make sure we have compatible NA
new = self.fill_value
if self._can_hold_element(new):
# We only get here for non-Extension Blocks, so _try_coerce_args
# is only relevant for DatetimeBlock and TimedeltaBlock
if lib.is_scalar(new):
new = convert_scalar_for_putitemlike(new, new_values.dtype)
if transpose:
new_values = new_values.T
# If the default repeat behavior in np.putmask would go in the
# wrong direction, then explicitly repeat and reshape new instead
if getattr(new, "ndim", 0) >= 1:
if self.ndim - 1 == new.ndim and axis == 1:
new = np.repeat(new, new_values.shape[-1]).reshape(self.shape)
new = new.astype(new_values.dtype)
# we require exact matches between the len of the
# values we are setting (or is compat). np.putmask
# doesn't check this and will simply truncate / pad
# the output, but we want sane error messages
#
# TODO: this prob needs some better checking
# for 2D cases
if (
is_list_like(new)
and np.any(mask[mask])
and getattr(new, "ndim", 1) == 1
):
if mask[mask].shape[-1] == len(new):
# GH 30567
# If length of ``new`` is less than the length of ``new_values``,
# `np.putmask` would first repeat the ``new`` array and then
# assign the masked values hence produces incorrect result.
# `np.place` on the other hand uses the ``new`` values at it is
# to place in the masked locations of ``new_values``
np.place(new_values, mask, new)
elif mask.shape[-1] == len(new) or len(new) == 1:
np.putmask(new_values, mask, new)
else:
raise ValueError("cannot assign mismatch length to masked array")
else:
np.putmask(new_values, mask, new)
# maybe upcast me
elif mask.any():
if transpose:
mask = mask.T
if isinstance(new, np.ndarray):
new = new.T
axis = new_values.ndim - axis - 1
# Pseudo-broadcast
if getattr(new, "ndim", 0) >= 1:
if self.ndim - 1 == new.ndim:
new_shape = list(new.shape)
new_shape.insert(axis, 1)
new = new.reshape(tuple(new_shape))
# operate column-by-column
def f(mask, val, idx):
if idx is None:
# ndim==1 case.
n = new
else:
if isinstance(new, np.ndarray):
n = np.squeeze(new[idx % new.shape[0]])
else:
n = np.array(new)
# type of the new block
dtype, _ = maybe_promote(n.dtype)
# we need to explicitly astype here to make a copy
n = n.astype(dtype)
nv = _putmask_smart(val, mask, n)
return nv
new_blocks = self.split_and_operate(mask, f, inplace)
return new_blocks
if inplace:
return [self]
if transpose:
new_values = new_values.T
return [self.make_block(new_values)]
def coerce_to_target_dtype(self, other):
"""
coerce the current block to a dtype compat for other
we will return a block, possibly object, and not raise
we can also safely try to coerce to the same dtype
and will receive the same block
"""
# if we cannot then coerce to object
dtype, _ = infer_dtype_from(other, pandas_dtype=True)
if is_dtype_equal(self.dtype, dtype):
return self
if self.is_bool or is_object_dtype(dtype) or is_bool_dtype(dtype):
# we don't upcast to bool
return self.astype(object)
elif (self.is_float or self.is_complex) and (
is_integer_dtype(dtype) or is_float_dtype(dtype)
):
# don't coerce float/complex to int
return self
elif (
self.is_datetime
or is_datetime64_dtype(dtype)
or is_datetime64tz_dtype(dtype)
):
# not a datetime
if not (
(is_datetime64_dtype(dtype) or is_datetime64tz_dtype(dtype))
and self.is_datetime
):
return self.astype(object)
# don't upcast timezone with different timezone or no timezone
mytz = getattr(self.dtype, "tz", None)
othertz = getattr(dtype, "tz", None)
if not tz_compare(mytz, othertz):
return self.astype(object)
raise AssertionError(
f"possible recursion in coerce_to_target_dtype: {self} {other}"
)
elif self.is_timedelta or is_timedelta64_dtype(dtype):
# not a timedelta
if not (is_timedelta64_dtype(dtype) and self.is_timedelta):
return self.astype(object)
raise AssertionError(
f"possible recursion in coerce_to_target_dtype: {self} {other}"
)
try:
return self.astype(dtype)
except (ValueError, TypeError, OverflowError):
return self.astype(object)
def interpolate(
self,
method="pad",
axis=0,
index=None,
inplace=False,
limit=None,
limit_direction="forward",
limit_area=None,
fill_value=None,
coerce=False,
downcast=None,
**kwargs,
):
inplace = validate_bool_kwarg(inplace, "inplace")
def check_int_bool(self, inplace):
# Only FloatBlocks will contain NaNs.
# timedelta subclasses IntBlock
if (self.is_bool or self.is_integer) and not self.is_timedelta:
if inplace:
return self
else:
return self.copy()
# a fill na type method
try:
m = missing.clean_fill_method(method)
except ValueError:
m = None
if m is not None:
r = check_int_bool(self, inplace)
if r is not None:
return r
return self._interpolate_with_fill(
method=m,
axis=axis,
inplace=inplace,
limit=limit,
fill_value=fill_value,
coerce=coerce,
downcast=downcast,
)
# validate the interp method
m = missing.clean_interp_method(method, **kwargs)
r = check_int_bool(self, inplace)
if r is not None:
return r
return self._interpolate(
method=m,
index=index,
axis=axis,
limit=limit,
limit_direction=limit_direction,
limit_area=limit_area,
fill_value=fill_value,
inplace=inplace,
downcast=downcast,
**kwargs,
)
def _interpolate_with_fill(
self,
method="pad",
axis=0,
inplace=False,
limit=None,
fill_value=None,
coerce=False,
downcast=None,
) -> List["Block"]:
""" fillna but using the interpolate machinery """
inplace = validate_bool_kwarg(inplace, "inplace")
# if we are coercing, then don't force the conversion
# if the block can't hold the type
if coerce:
if not self._can_hold_na:
if inplace:
return [self]
else:
return [self.copy()]
values = self.values if inplace else self.values.copy()
# We only get here for non-ExtensionBlock
fill_value = convert_scalar_for_putitemlike(fill_value, self.values.dtype)
values = missing.interpolate_2d(
values,
method=method,
axis=axis,
limit=limit,
fill_value=fill_value,
dtype=self.dtype,
)
blocks = [self.make_block_same_class(values, ndim=self.ndim)]
return self._maybe_downcast(blocks, downcast)
def _interpolate(
self,
method=None,
index=None,
fill_value=None,
axis=0,
limit=None,
limit_direction="forward",
limit_area=None,
inplace=False,
downcast=None,
**kwargs,
) -> List["Block"]:
""" interpolate using scipy wrappers """
inplace = validate_bool_kwarg(inplace, "inplace")
data = self.values if inplace else self.values.copy()
# only deal with floats
if not self.is_float:
if not self.is_integer:
return [self]
data = data.astype(np.float64)
if fill_value is None:
fill_value = self.fill_value
if method in ("krogh", "piecewise_polynomial", "pchip"):
if not index.is_monotonic:
raise ValueError(
f"{method} interpolation requires that the index be monotonic."
)
# process 1-d slices in the axis direction
def func(x):
# process a 1-d slice, returning it
# should the axis argument be handled below in apply_along_axis?
# i.e. not an arg to missing.interpolate_1d
return missing.interpolate_1d(
index,
x,
method=method,
limit=limit,
limit_direction=limit_direction,
limit_area=limit_area,
fill_value=fill_value,
bounds_error=False,
**kwargs,
)
# interp each column independently
interp_values = np.apply_along_axis(func, axis, data)
blocks = [self.make_block_same_class(interp_values)]
return self._maybe_downcast(blocks, downcast)
def take_nd(self, indexer, axis: int, new_mgr_locs=None, fill_tuple=None):
"""
Take values according to indexer and return them as a block.bb
"""
# algos.take_nd dispatches for DatetimeTZBlock, CategoricalBlock
# so need to preserve types
# sparse is treated like an ndarray, but needs .get_values() shaping
values = self.values
if fill_tuple is None:
fill_value = self.fill_value
allow_fill = False
else:
fill_value = fill_tuple[0]
allow_fill = True
new_values = algos.take_nd(
values, indexer, axis=axis, allow_fill=allow_fill, fill_value=fill_value
)
# Called from three places in managers, all of which satisfy
# this assertion
assert not (axis == 0 and new_mgr_locs is None)
if new_mgr_locs is None:
new_mgr_locs = self.mgr_locs
if not is_dtype_equal(new_values.dtype, self.dtype):
return self.make_block(new_values, new_mgr_locs)
else:
return self.make_block_same_class(new_values, new_mgr_locs)
def diff(self, n: int, axis: int = 1) -> List["Block"]:
""" return block for the diff of the values """
new_values = algos.diff(self.values, n, axis=axis, stacklevel=7)
# We use block_shape for ExtensionBlock subclasses, which may call here
# via a super.
new_values = _block_shape(new_values, ndim=self.ndim)
return [self.make_block(values=new_values)]
def shift(self, periods, axis: int = 0, fill_value=None):
""" shift the block by periods, possibly upcast """
# convert integer to float if necessary. need to do a lot more than
# that, handle boolean etc also
new_values, fill_value = maybe_upcast(self.values, fill_value)
new_values = shift(new_values, periods, axis, fill_value)
return [self.make_block(new_values)]
def where(
self,
other,
cond,
align: bool = True,
errors="raise",
try_cast: bool = False,
axis: int = 0,
) -> List["Block"]:
"""
evaluate the block; return result block(s) from the result
Parameters
----------
other : a ndarray/object
cond : the condition to respect
align : bool, default True
Perform alignment on other/cond.
errors : str, {'raise', 'ignore'}, default 'raise'
- ``raise`` : allow exceptions to be raised
- ``ignore`` : suppress exceptions. On error return original object
axis : int, default 0
Returns
-------
a new block(s), the result of the func
"""
import pandas.core.computation.expressions as expressions
assert errors in ["raise", "ignore"]
transpose = self.ndim == 2
values = self.values
orig_other = other
if transpose:
values = values.T
other = getattr(other, "_values", getattr(other, "values", other))
cond = getattr(cond, "values", cond)
# If the default broadcasting would go in the wrong direction, then
# explicitly reshape other instead
if getattr(other, "ndim", 0) >= 1:
if values.ndim - 1 == other.ndim and axis == 1:
other = other.reshape(tuple(other.shape + (1,)))
elif transpose and values.ndim == self.ndim - 1:
cond = cond.T
if not hasattr(cond, "shape"):
raise ValueError("where must have a condition that is ndarray like")
def where_func(cond, values, other):
if not (
(self.is_integer or self.is_bool)
and lib.is_float(other)
and np.isnan(other)
):
# np.where will cast integer array to floats in this case
if not self._can_hold_element(other):
raise TypeError
if lib.is_scalar(other) and isinstance(values, np.ndarray):
# convert datetime to datetime64, timedelta to timedelta64
other = convert_scalar_for_putitemlike(other, values.dtype)
# By the time we get here, we should have all Series/Index
# args extracted to ndarray
fastres = expressions.where(cond, values, other)
return fastres
if cond.ravel().all():
result = values
else:
# see if we can operate on the entire block, or need item-by-item
# or if we are a single block (ndim == 1)
try:
result = where_func(cond, values, other)
except TypeError:
# we cannot coerce, return a compat dtype
# we are explicitly ignoring errors
block = self.coerce_to_target_dtype(other)
blocks = block.where(
orig_other,
cond,
align=align,
errors=errors,
try_cast=try_cast,
axis=axis,
)
return self._maybe_downcast(blocks, "infer")
if self._can_hold_na or self.ndim == 1:
if transpose:
result = result.T
return [self.make_block(result)]
# might need to separate out blocks
axis = cond.ndim - 1
cond = cond.swapaxes(axis, 0)
mask = np.array([cond[i].all() for i in range(cond.shape[0])], dtype=bool)
result_blocks = []
for m in [mask, ~mask]:
if m.any():
taken = result.take(m.nonzero()[0], axis=axis)
r = maybe_downcast_numeric(taken, self.dtype)
nb = self.make_block(r.T, placement=self.mgr_locs[m])
result_blocks.append(nb)
return result_blocks
def equals(self, other) -> bool:
if self.dtype != other.dtype or self.shape != other.shape:
return False
return array_equivalent(self.values, other.values)
def _unstack(self, unstacker_func, new_columns, n_rows, fill_value):
"""
Return a list of unstacked blocks of self
Parameters
----------
unstacker_func : callable
Partially applied unstacker.
new_columns : Index
All columns of the unstacked BlockManager.
n_rows : int
Only used in ExtensionBlock._unstack
fill_value : int
Only used in ExtensionBlock._unstack
Returns
-------
blocks : list of Block
New blocks of unstacked values.
mask : array_like of bool
The mask of columns of `blocks` we should keep.
"""
unstacker = unstacker_func(self.values.T)
new_items = unstacker.get_new_columns()
new_placement = new_columns.get_indexer(new_items)
new_values, mask = unstacker.get_new_values()
mask = mask.any(0)
new_values = new_values.T[mask]
new_placement = new_placement[mask]
blocks = [make_block(new_values, placement=new_placement)]
return blocks, mask
def quantile(self, qs, interpolation="linear", axis: int = 0):
"""
compute the quantiles of the
Parameters
----------
qs: a scalar or list of the quantiles to be computed
interpolation: type of interpolation, default 'linear'
axis: axis to compute, default 0
Returns
-------
Block
"""
# We should always have ndim == 2 because Series dispatches to DataFrame
assert self.ndim == 2
values = self.get_values()
is_empty = values.shape[axis] == 0
orig_scalar = not is_list_like(qs)
if orig_scalar:
# make list-like, unpack later
qs = [qs]
if is_empty:
# create the array of na_values
# 2d len(values) * len(qs)
result = np.repeat(
np.array([self.fill_value] * len(qs)), len(values)
).reshape(len(values), len(qs))
else:
# asarray needed for Sparse, see GH#24600
mask = np.asarray(isna(values))
result = nanpercentile(
values,
np.array(qs) * 100,
axis=axis,
na_value=self.fill_value,
mask=mask,
ndim=values.ndim,
interpolation=interpolation,
)
result = np.array(result, copy=False)
result = result.T
if orig_scalar and not lib.is_scalar(result):
# result could be scalar in case with is_empty and self.ndim == 1
assert result.shape[-1] == 1, result.shape
result = result[..., 0]
result = lib.item_from_zerodim(result)
ndim = np.ndim(result)
return make_block(result, placement=np.arange(len(result)), ndim=ndim)
def _replace_coerce(
self,
to_replace,
value,
inplace: bool = True,
regex: bool = False,
convert: bool = False,
mask=None,
):
"""
Replace value corresponding to the given boolean array with another
value.
Parameters
----------
to_replace : object or pattern
Scalar to replace or regular expression to match.
value : object
Replacement object.
inplace : bool, default True
Perform inplace modification.
regex : bool, default False
If true, perform regular expression substitution.
convert : bool, default True
If true, try to coerce any object types to better types.
mask : array-like of bool, optional
True indicate corresponding element is ignored.
Returns
-------
A new block if there is anything to replace or the original block.
"""
if mask.any():
if not regex:
self = self.coerce_to_target_dtype(value)
return self.putmask(mask, value, inplace=inplace)
else:
return self._replace_single(
to_replace,
value,
inplace=inplace,
regex=regex,
convert=convert,
mask=mask,
)
return self
class ExtensionBlock(Block):
"""
Block for holding extension types.
Notes
-----
This holds all 3rd-party extension array types. It's also the immediate
parent class for our internal extension types' blocks, CategoricalBlock.
ExtensionArrays are limited to 1-D.
"""
_can_consolidate = False
_verify_integrity = False
_validate_ndim = False
is_extension = True
def __init__(self, values, placement, ndim=None):
"""
Initialize a non-consolidatable block.
'ndim' may be inferred from 'placement'.
This will call continue to call __init__ for the other base
classes mixed in with this Mixin.
"""
values = self._maybe_coerce_values(values)
# Placement must be converted to BlockPlacement so that we can check
# its length
if not isinstance(placement, libinternals.BlockPlacement):
placement = libinternals.BlockPlacement(placement)
# Maybe infer ndim from placement
if ndim is None:
if len(placement) != 1:
ndim = 1
else:
ndim = 2
super().__init__(values, placement, ndim=ndim)
if self.ndim == 2 and len(self.mgr_locs) != 1:
# TODO(2DEA): check unnecessary with 2D EAs
raise AssertionError("block.size != values.size")
@property
def shape(self):
if self.ndim == 1:
return ((len(self.values)),)
return (len(self.mgr_locs), len(self.values))
def iget(self, col):
if self.ndim == 2 and isinstance(col, tuple):
col, loc = col
if not com.is_null_slice(col) and col != 0:
raise IndexError(f"{self} only contains one item")
elif isinstance(col, slice):
if col != slice(None):
raise NotImplementedError(col)
return self.values[[loc]]
return self.values[loc]
else:
if col != 0:
raise IndexError(f"{self} only contains one item")
return self.values
def should_store(self, value):
return isinstance(value, self._holder)
def set(self, locs, values, check=False):
assert locs.tolist() == [0]
self.values = values
def putmask(
self, mask, new, align=True, inplace=False, axis=0, transpose=False,
):
"""
putmask the data to the block; we must be a single block and not
generate other blocks
return the resulting block
Parameters
----------
mask : the condition to respect
new : a ndarray/object
align : boolean, perform alignment on other/cond, default is True
inplace : perform inplace modification, default is False
Returns
-------
a new block, the result of the putmask
"""
inplace = validate_bool_kwarg(inplace, "inplace")
# use block's copy logic.
# .values may be an Index which does shallow copy by default
new_values = self.values if inplace else self.copy().values
if isinstance(new, np.ndarray) and len(new) == len(mask):
new = new[mask]
mask = _safe_reshape(mask, new_values.shape)
new_values[mask] = new
return [self.make_block(values=new_values)]
def _get_unstack_items(self, unstacker, new_columns):
"""
Get the placement, values, and mask for a Block unstack.
This is shared between ObjectBlock and ExtensionBlock. They
differ in that ObjectBlock passes the values, while ExtensionBlock
passes the dummy ndarray of positions to be used by a take
later.
Parameters
----------
unstacker : pandas.core.reshape.reshape._Unstacker
new_columns : Index
All columns of the unstacked BlockManager.
Returns
-------
new_placement : ndarray[int]
The placement of the new columns in `new_columns`.
new_values : Union[ndarray, ExtensionArray]
The first return value from _Unstacker.get_new_values.
mask : ndarray[bool]
The second return value from _Unstacker.get_new_values.
"""
# shared with ExtensionBlock
new_items = unstacker.get_new_columns()
new_placement = new_columns.get_indexer(new_items)
new_values, mask = unstacker.get_new_values()
mask = mask.any(0)
return new_placement, new_values, mask
def _maybe_coerce_values(self, values):
"""
Unbox to an extension array.
This will unbox an ExtensionArray stored in an Index or Series.
ExtensionArrays pass through. No dtype coercion is done.
Parameters
----------
values : Index, Series, ExtensionArray
Returns
-------
ExtensionArray
"""
return extract_array(values)
@property
def _holder(self):
# For extension blocks, the holder is values-dependent.
return type(self.values)
@property
def fill_value(self):
# Used in reindex_indexer
return self.values.dtype.na_value
@property
def _can_hold_na(self):
# The default ExtensionArray._can_hold_na is True
return self._holder._can_hold_na
@property
def is_view(self) -> bool:
"""Extension arrays are never treated as views."""
return False
@property
def is_numeric(self):
return self.values.dtype._is_numeric
def setitem(self, indexer, value):
"""
Set the value inplace, returning a same-typed block.
This differs from Block.setitem by not allowing setitem to change
the dtype of the Block.
Parameters
----------
indexer : tuple, list-like, array-like, slice
The subset of self.values to set
value : object
The value being set
Returns
-------
Block
Notes
-----
`indexer` is a direct slice/positional indexer. `value` must
be a compatible shape.
"""
if isinstance(indexer, tuple):
# we are always 1-D
indexer = indexer[0]
check_setitem_lengths(indexer, value, self.values)
self.values[indexer] = value
return self
def get_values(self, dtype=None):
# ExtensionArrays must be iterable, so this works.
values = np.asarray(self.values)
if values.ndim == self.ndim - 1:
values = values.reshape((1,) + values.shape)
return values
def array_values(self) -> ExtensionArray:
return self.values
def to_native_types(self, slicer=None, na_rep="nan", quoting=None, **kwargs):
"""override to use ExtensionArray astype for the conversion"""
values = self.values
if slicer is not None:
values = values[slicer]
mask = isna(values)
values = np.asarray(values.astype(object))
values[mask] = na_rep
# we are expected to return a 2-d ndarray
return values.reshape(1, len(values))
def take_nd(self, indexer, axis: int = 0, new_mgr_locs=None, fill_tuple=None):
"""
Take values according to indexer and return them as a block.
"""
if fill_tuple is None:
fill_value = None
else:
fill_value = fill_tuple[0]
# axis doesn't matter; we are really a single-dim object
# but are passed the axis depending on the calling routing
# if its REALLY axis 0, then this will be a reindex and not a take
new_values = self.values.take(indexer, fill_value=fill_value, allow_fill=True)
# Called from three places in managers, all of which satisfy
# this assertion
assert not (self.ndim == 1 and new_mgr_locs is None)
if new_mgr_locs is None:
new_mgr_locs = self.mgr_locs
return self.make_block_same_class(new_values, new_mgr_locs)
def _can_hold_element(self, element: Any) -> bool:
# XXX: We may need to think about pushing this onto the array.
# We're doing the same as CategoricalBlock here.
return True
def _slice(self, slicer):
""" return a slice of my values """
# slice the category
# return same dims as we currently have
if isinstance(slicer, tuple) and len(slicer) == 2:
if not com.is_null_slice(slicer[0]):
raise AssertionError("invalid slicing for a 1-ndim categorical")
slicer = slicer[1]
return self.values[slicer]
def concat_same_type(self, to_concat, placement=None):
"""
Concatenate list of single blocks of the same type.
"""
values = self._holder._concat_same_type([blk.values for blk in to_concat])
placement = placement or slice(0, len(values), 1)
return self.make_block_same_class(values, ndim=self.ndim, placement=placement)
def fillna(self, value, limit=None, inplace=False, downcast=None):
values = self.values if inplace else self.values.copy()
values = values.fillna(value=value, limit=limit)
return [
self.make_block_same_class(
values=values, placement=self.mgr_locs, ndim=self.ndim
)
]
def interpolate(
self, method="pad", axis=0, inplace=False, limit=None, fill_value=None, **kwargs
):
values = self.values if inplace else self.values.copy()
return self.make_block_same_class(
values=values.fillna(value=fill_value, method=method, limit=limit),
placement=self.mgr_locs,
)
def diff(self, n: int, axis: int = 1) -> List["Block"]:
if axis == 1:
# we are by definition 1D.
axis = 0
return super().diff(n, axis)
def shift(
self, periods: int, axis: int = 0, fill_value: Any = None,
) -> List["ExtensionBlock"]:
"""
Shift the block by `periods`.
Dispatches to underlying ExtensionArray and re-boxes in an
ExtensionBlock.
"""
return [
self.make_block_same_class(
self.values.shift(periods=periods, fill_value=fill_value),
placement=self.mgr_locs,
ndim=self.ndim,
)
]
def where(
self,
other,
cond,
align=True,
errors="raise",
try_cast: bool = False,
axis: int = 0,
) -> List["Block"]:
if isinstance(other, ABCDataFrame):
# ExtensionArrays are 1-D, so if we get here then
# `other` should be a DataFrame with a single column.
assert other.shape[1] == 1
other = other.iloc[:, 0]
other = extract_array(other, extract_numpy=True)
if isinstance(cond, ABCDataFrame):
assert cond.shape[1] == 1
cond = cond.iloc[:, 0]
cond = extract_array(cond, extract_numpy=True)
if lib.is_scalar(other) and isna(other):
# The default `other` for Series / Frame is np.nan
# we want to replace that with the correct NA value
# for the type
other = self.dtype.na_value
if is_sparse(self.values):
# TODO(SparseArray.__setitem__): remove this if condition
# We need to re-infer the type of the data after doing the
# where, for cases where the subtypes don't match
dtype = None
else:
dtype = self.dtype
result = self.values.copy()
icond = ~cond
if lib.is_scalar(other):
set_other = other
else:
set_other = other[icond]
try:
result[icond] = set_other
except (NotImplementedError, TypeError):
# NotImplementedError for class not implementing `__setitem__`
# TypeError for SparseArray, which implements just to raise
# a TypeError
result = self._holder._from_sequence(
np.where(cond, self.values, other), dtype=dtype
)
return [self.make_block_same_class(result, placement=self.mgr_locs)]
def _unstack(self, unstacker_func, new_columns, n_rows, fill_value):
# ExtensionArray-safe unstack.
# We override ObjectBlock._unstack, which unstacks directly on the
# values of the array. For EA-backed blocks, this would require
# converting to a 2-D ndarray of objects.
# Instead, we unstack an ndarray of integer positions, followed by
# a `take` on the actual values.
dummy_arr = np.arange(n_rows)
dummy_unstacker = functools.partial(unstacker_func, fill_value=-1)
unstacker = dummy_unstacker(dummy_arr)
new_placement, new_values, mask = self._get_unstack_items(
unstacker, new_columns
)
blocks = [
self.make_block_same_class(
self.values.take(indices, allow_fill=True, fill_value=fill_value),
[place],
)
for indices, place in zip(new_values.T, new_placement)
]
return blocks, mask
class ObjectValuesExtensionBlock(ExtensionBlock):
"""
Block providing backwards-compatibility for `.values`.
Used by PeriodArray and IntervalArray to ensure that
Series[T].values is an ndarray of objects.
"""
def external_values(self):
return self.values.astype(object)
class NumericBlock(Block):
__slots__ = ()
is_numeric = True
_can_hold_na = True
class FloatOrComplexBlock(NumericBlock):
__slots__ = ()
def equals(self, other) -> bool:
if self.dtype != other.dtype or self.shape != other.shape:
return False
left, right = self.values, other.values
return ((left == right) | (np.isnan(left) & np.isnan(right))).all()
class FloatBlock(FloatOrComplexBlock):
__slots__ = ()
is_float = True
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return issubclass(tipo.type, (np.floating, np.integer)) and not issubclass(
tipo.type, (np.datetime64, np.timedelta64)
)
return isinstance(
element, (float, int, np.floating, np.int_)
) and not isinstance(
element,
(bool, np.bool_, datetime, timedelta, np.datetime64, np.timedelta64),
)
def to_native_types(
self,
slicer=None,
na_rep="",
float_format=None,
decimal=".",
quoting=None,
**kwargs,
):
""" convert to our native types format, slicing if desired """
values = self.values
if slicer is not None:
values = values[:, slicer]
# see gh-13418: no special formatting is desired at the
# output (important for appropriate 'quoting' behaviour),
# so do not pass it through the FloatArrayFormatter
if float_format is None and decimal == ".":
mask = isna(values)
if not quoting:
values = values.astype(str)
else:
values = np.array(values, dtype="object")
values[mask] = na_rep
return values
from pandas.io.formats.format import FloatArrayFormatter
formatter = FloatArrayFormatter(
values,
na_rep=na_rep,
float_format=float_format,
decimal=decimal,
quoting=quoting,
fixed_width=False,
)
return formatter.get_result_as_array()
def should_store(self, value) -> bool:
# when inserting a column should not coerce integers to floats
# unnecessarily
return issubclass(value.dtype.type, np.floating) and value.dtype == self.dtype
class ComplexBlock(FloatOrComplexBlock):
__slots__ = ()
is_complex = True
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return issubclass(tipo.type, (np.floating, np.integer, np.complexfloating))
return isinstance(
element, (float, int, complex, np.float_, np.int_)
) and not isinstance(element, (bool, np.bool_))
def should_store(self, value) -> bool:
return issubclass(value.dtype.type, np.complexfloating)
class IntBlock(NumericBlock):
__slots__ = ()
is_integer = True
_can_hold_na = False
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return (
issubclass(tipo.type, np.integer)
and not issubclass(tipo.type, (np.datetime64, np.timedelta64))
and self.dtype.itemsize >= tipo.itemsize
)
return is_integer(element)
def should_store(self, value) -> bool:
return is_integer_dtype(value) and value.dtype == self.dtype
class DatetimeLikeBlockMixin:
"""Mixin class for DatetimeBlock, DatetimeTZBlock, and TimedeltaBlock."""
@property
def _holder(self):
return DatetimeArray
@property
def fill_value(self):
return np.datetime64("NaT", "ns")
def get_values(self, dtype=None):
"""
return object dtype as boxed values, such as Timestamps/Timedelta
"""
if is_object_dtype(dtype):
values = self.values.ravel()
result = self._holder(values).astype(object)
return result.reshape(self.values.shape)
return self.values
def internal_values(self):
# Override to return DatetimeArray and TimedeltaArray
return self.array_values()
def iget(self, key):
# GH#31649 we need to wrap scalars in Timestamp/Timedelta
# TODO(EA2D): this can be removed if we ever have 2D EA
result = super().iget(key)
if isinstance(result, np.datetime64):
result = Timestamp(result)
elif isinstance(result, np.timedelta64):
result = Timedelta(result)
return result
def shift(self, periods, axis=0, fill_value=None):
# TODO(EA2D) this is unnecessary if these blocks are backed by 2D EAs
values = self.array_values()
new_values = values.shift(periods, fill_value=fill_value, axis=axis)
return self.make_block_same_class(new_values)
class DatetimeBlock(DatetimeLikeBlockMixin, Block):
__slots__ = ()
is_datetime = True
def __init__(self, values, placement, ndim=None):
values = self._maybe_coerce_values(values)
super().__init__(values, placement=placement, ndim=ndim)
@property
def _can_hold_na(self):
return True
def _maybe_coerce_values(self, values):
"""
Input validation for values passed to __init__. Ensure that
we have datetime64ns, coercing if necessary.
Parameters
----------
values : array-like
Must be convertible to datetime64
Returns
-------
values : ndarray[datetime64ns]
Overridden by DatetimeTZBlock.
"""
if values.dtype != _NS_DTYPE:
values = conversion.ensure_datetime64ns(values)
if isinstance(values, DatetimeArray):
values = values._data
assert isinstance(values, np.ndarray), type(values)
return values
def astype(self, dtype, copy: bool = False, errors: str = "raise"):
"""
these automatically copy, so copy=True has no effect
raise on an except if raise == True
"""
dtype = pandas_dtype(dtype)
# if we are passed a datetime64[ns, tz]
if is_datetime64tz_dtype(dtype):
values = self.values
if copy:
# this should be the only copy
values = values.copy()
if getattr(values, "tz", None) is None:
values = DatetimeArray(values).tz_localize("UTC")
values = values.tz_convert(dtype.tz)
return self.make_block(values)
# delegate
return super().astype(dtype=dtype, copy=copy, errors=errors)
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
if self.is_datetimetz:
# require exact match, since non-nano does not exist
return is_dtype_equal(tipo, self.dtype) or is_valid_nat_for_dtype(
element, self.dtype
)
# GH#27419 if we get a non-nano datetime64 object
return is_datetime64_dtype(tipo)
elif element is NaT:
return True
elif isinstance(element, datetime):
if self.is_datetimetz:
return tz_compare(element.tzinfo, self.dtype.tz)
return element.tzinfo is None
return is_valid_nat_for_dtype(element, self.dtype)
def to_native_types(
self, slicer=None, na_rep=None, date_format=None, quoting=None, **kwargs
):
""" convert to our native types format, slicing if desired """
values = self.values
i8values = self.values.view("i8")
if slicer is not None:
values = values[..., slicer]
i8values = i8values[..., slicer]
from pandas.io.formats.format import _get_format_datetime64_from_values
fmt = _get_format_datetime64_from_values(values, date_format)
result = tslib.format_array_from_datetime(
i8values.ravel(),
tz=getattr(self.values, "tz", None),
format=fmt,
na_rep=na_rep,
).reshape(i8values.shape)
return np.atleast_2d(result)
def should_store(self, value) -> bool:
return is_datetime64_dtype(value.dtype)
def set(self, locs, values):
"""
Modify Block in-place with new item value
Returns
-------
None
"""
values = conversion.ensure_datetime64ns(values, copy=False)
self.values[locs] = values
def external_values(self):
return np.asarray(self.values.astype("datetime64[ns]", copy=False))
def array_values(self) -> ExtensionArray:
return DatetimeArray._simple_new(self.values)
class DatetimeTZBlock(ExtensionBlock, DatetimeBlock):
""" implement a datetime64 block with a tz attribute """
__slots__ = ()
is_datetimetz = True
is_extension = True
internal_values = Block.internal_values
_can_hold_element = DatetimeBlock._can_hold_element
to_native_types = DatetimeBlock.to_native_types
fill_value = np.datetime64("NaT", "ns")
@property
def _holder(self):
return DatetimeArray
def _maybe_coerce_values(self, values):
"""
Input validation for values passed to __init__. Ensure that
we have datetime64TZ, coercing if necessary.
Parameters
----------
values : array-like
Must be convertible to datetime64
Returns
-------
values : DatetimeArray
"""
if not isinstance(values, self._holder):
values = self._holder(values)
if values.tz is None:
raise ValueError("cannot create a DatetimeTZBlock without a tz")
return values
@property
def is_view(self) -> bool:
""" return a boolean if I am possibly a view """
# check the ndarray values of the DatetimeIndex values
return self.values._data.base is not None
def get_values(self, dtype=None):
"""
Returns an ndarray of values.
Parameters
----------
dtype : np.dtype
Only `object`-like dtypes are respected here (not sure
why).
Returns
-------
values : ndarray
When ``dtype=object``, then and object-dtype ndarray of
boxed values is returned. Otherwise, an M8[ns] ndarray
is returned.
DatetimeArray is always 1-d. ``get_values`` will reshape
the return value to be the same dimensionality as the
block.
"""
values = self.values
if is_object_dtype(dtype):
values = values.astype(object)
values = np.asarray(values)
if self.ndim == 2:
# Ensure that our shape is correct for DataFrame.
# ExtensionArrays are always 1-D, even in a DataFrame when
# the analogous NumPy-backed column would be a 2-D ndarray.
values = values.reshape(1, -1)
return values
def _slice(self, slicer):
""" return a slice of my values """
if isinstance(slicer, tuple):
col, loc = slicer
if not com.is_null_slice(col) and col != 0:
raise IndexError(f"{self} only contains one item")
return self.values[loc]
return self.values[slicer]
def diff(self, n: int, axis: int = 0) -> List["Block"]:
"""
1st discrete difference.
Parameters
----------
n : int
Number of periods to diff.
axis : int, default 0
Axis to diff upon.
Returns
-------
A list with a new TimeDeltaBlock.
Notes
-----
The arguments here are mimicking shift so they are called correctly
by apply.
"""
if axis == 0:
# Cannot currently calculate diff across multiple blocks since this
# function is invoked via apply
raise NotImplementedError
new_values = (self.values - self.shift(n, axis=axis)[0].values).asi8
# Reshape the new_values like how algos.diff does for timedelta data
new_values = new_values.reshape(1, len(new_values))
new_values = new_values.astype("timedelta64[ns]")
return [TimeDeltaBlock(new_values, placement=self.mgr_locs.indexer)]
def concat_same_type(self, to_concat, placement=None):
# need to handle concat([tz1, tz2]) here, since DatetimeArray
# only handles cases where all the tzs are the same.
# Instead of placing the condition here, it could also go into the
# is_uniform_join_units check, but I'm not sure what is better.
if len({x.dtype for x in to_concat}) > 1:
values = concat_datetime([x.values for x in to_concat])
placement = placement or slice(0, len(values), 1)
if self.ndim > 1:
values = np.atleast_2d(values)
return ObjectBlock(values, ndim=self.ndim, placement=placement)
return super().concat_same_type(to_concat, placement)
def fillna(self, value, limit=None, inplace=False, downcast=None):
# We support filling a DatetimeTZ with a `value` whose timezone
# is different by coercing to object.
if self._can_hold_element(value):
return super().fillna(value, limit, inplace, downcast)
# different timezones, or a non-tz
return self.astype(object).fillna(
value, limit=limit, inplace=inplace, downcast=downcast
)
def setitem(self, indexer, value):
# https://github.com/pandas-dev/pandas/issues/24020
# Need a dedicated setitem until #24020 (type promotion in setitem
# for extension arrays) is designed and implemented.
if self._can_hold_element(value) or (
isinstance(indexer, np.ndarray) and indexer.size == 0
):
return super().setitem(indexer, value)
obj_vals = self.values.astype(object)
newb = make_block(
obj_vals, placement=self.mgr_locs, klass=ObjectBlock, ndim=self.ndim
)
return newb.setitem(indexer, value)
def equals(self, other) -> bool:
# override for significant performance improvement
if self.dtype != other.dtype or self.shape != other.shape:
return False
return (self.values.view("i8") == other.values.view("i8")).all()
def quantile(self, qs, interpolation="linear", axis=0):
naive = self.values.view("M8[ns]")
# kludge for 2D block with 1D values
naive = naive.reshape(self.shape)
blk = self.make_block(naive)
res_blk = blk.quantile(qs, interpolation=interpolation, axis=axis)
# ravel is kludge for 2D block with 1D values, assumes column-like
aware = self._holder(res_blk.values.ravel(), dtype=self.dtype)
return self.make_block_same_class(aware, ndim=res_blk.ndim)
class TimeDeltaBlock(DatetimeLikeBlockMixin, IntBlock):
__slots__ = ()
is_timedelta = True
_can_hold_na = True
is_numeric = False
fill_value = np.timedelta64("NaT", "ns")
def __init__(self, values, placement, ndim=None):
if values.dtype != _TD_DTYPE:
values = conversion.ensure_timedelta64ns(values)
if isinstance(values, TimedeltaArray):
values = values._data
assert isinstance(values, np.ndarray), type(values)
super().__init__(values, placement=placement, ndim=ndim)
@property
def _holder(self):
return TimedeltaArray
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return issubclass(tipo.type, np.timedelta64)
elif element is NaT:
return True
elif isinstance(element, (timedelta, np.timedelta64)):
return True
return is_valid_nat_for_dtype(element, self.dtype)
def fillna(self, value, **kwargs):
# allow filling with integers to be
# interpreted as nanoseconds
if is_integer(value):
# Deprecation GH#24694, GH#19233
raise TypeError(
"Passing integers to fillna for timedelta64[ns] dtype is no "
"longer supported. To obtain the old behavior, pass "
"`pd.Timedelta(seconds=n)` instead."
)
return super().fillna(value, **kwargs)
def should_store(self, value) -> bool:
return is_timedelta64_dtype(value.dtype)
def to_native_types(self, slicer=None, na_rep=None, quoting=None, **kwargs):
""" convert to our native types format, slicing if desired """
values = self.values
if slicer is not None:
values = values[:, slicer]
mask = isna(values)
rvalues = np.empty(values.shape, dtype=object)
if na_rep is None:
na_rep = "NaT"
rvalues[mask] = na_rep
imask = (~mask).ravel()
# FIXME:
# should use the formats.format.Timedelta64Formatter here
# to figure what format to pass to the Timedelta
# e.g. to not show the decimals say
rvalues.flat[imask] = np.array(
[Timedelta(val)._repr_base(format="all") for val in values.ravel()[imask]],
dtype=object,
)
return rvalues
def external_values(self):
return np.asarray(self.values.astype("timedelta64[ns]", copy=False))
def array_values(self) -> ExtensionArray:
return TimedeltaArray._simple_new(self.values)
class BoolBlock(NumericBlock):
__slots__ = ()
is_bool = True
_can_hold_na = False
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return issubclass(tipo.type, np.bool_)
return isinstance(element, (bool, np.bool_))
def should_store(self, value) -> bool:
return issubclass(value.dtype.type, np.bool_) and not is_extension_array_dtype(
value
)
def replace(
self, to_replace, value, inplace=False, filter=None, regex=False, convert=True
):
inplace = validate_bool_kwarg(inplace, "inplace")
to_replace_values = np.atleast_1d(to_replace)
if not np.can_cast(to_replace_values, bool):
return self
return super().replace(
to_replace,
value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
class ObjectBlock(Block):
__slots__ = ()
is_object = True
_can_hold_na = True
def __init__(self, values, placement=None, ndim=2):
if issubclass(values.dtype.type, str):
values = np.array(values, dtype=object)
super().__init__(values, ndim=ndim, placement=placement)
@property
def is_bool(self):
"""
we can be a bool if we have only bool values but are of type
object
"""
return lib.is_bool_array(self.values.ravel())
def convert(
self,
copy: bool = True,
datetime: bool = True,
numeric: bool = True,
timedelta: bool = True,
coerce: bool = False,
):
"""
attempt to coerce any object types to better types return a copy of
the block (if copy = True) by definition we ARE an ObjectBlock!!!!!
can return multiple blocks!
"""
# operate column-by-column
def f(mask, val, idx):
shape = val.shape
values = soft_convert_objects(
val.ravel(),
datetime=datetime,
numeric=numeric,
timedelta=timedelta,
coerce=coerce,
copy=copy,
)
if isinstance(values, np.ndarray):
# TODO: allow EA once reshape is supported
values = values.reshape(shape)
values = _block_shape(values, ndim=self.ndim)
return values
if self.ndim == 2:
blocks = self.split_and_operate(None, f, False)
else:
values = f(None, self.values.ravel(), None)
blocks = [make_block(values, ndim=self.ndim, placement=self.mgr_locs)]
return blocks
def _maybe_downcast(self, blocks: List["Block"], downcast=None) -> List["Block"]:
if downcast is not None:
return blocks
# split and convert the blocks
return _extend_blocks([b.convert(datetime=True, numeric=False) for b in blocks])
def _can_hold_element(self, element: Any) -> bool:
return True
def should_store(self, value) -> bool:
return not (
issubclass(
value.dtype.type,
(np.integer, np.floating, np.complexfloating, np.datetime64, np.bool_),
)
or is_extension_array_dtype(value)
)
def replace(
self, to_replace, value, inplace=False, filter=None, regex=False, convert=True
):
to_rep_is_list = is_list_like(to_replace)
value_is_list = is_list_like(value)
both_lists = to_rep_is_list and value_is_list
either_list = to_rep_is_list or value_is_list
result_blocks = []
blocks = [self]
if not either_list and is_re(to_replace):
return self._replace_single(
to_replace,
value,
inplace=inplace,
filter=filter,
regex=True,
convert=convert,
)
elif not (either_list or regex):
return super().replace(
to_replace,
value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
elif both_lists:
for to_rep, v in zip(to_replace, value):
result_blocks = []
for b in blocks:
result = b._replace_single(
to_rep,
v,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
result_blocks = _extend_blocks(result, result_blocks)
blocks = result_blocks
return result_blocks
elif to_rep_is_list and regex:
for to_rep in to_replace:
result_blocks = []
for b in blocks:
result = b._replace_single(
to_rep,
value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
result_blocks = _extend_blocks(result, result_blocks)
blocks = result_blocks
return result_blocks
return self._replace_single(
to_replace,
value,
inplace=inplace,
filter=filter,
convert=convert,
regex=regex,
)
def _replace_single(
self,
to_replace,
value,
inplace=False,
filter=None,
regex=False,
convert=True,
mask=None,
):
"""
Replace elements by the given value.
Parameters
----------
to_replace : object or pattern
Scalar to replace or regular expression to match.
value : object
Replacement object.
inplace : bool, default False
Perform inplace modification.
filter : list, optional
regex : bool, default False
If true, perform regular expression substitution.
convert : bool, default True
If true, try to coerce any object types to better types.
mask : array-like of bool, optional
True indicate corresponding element is ignored.
Returns
-------
a new block, the result after replacing
"""
inplace = validate_bool_kwarg(inplace, "inplace")
# to_replace is regex compilable
to_rep_re = regex and is_re_compilable(to_replace)
# regex is regex compilable
regex_re = is_re_compilable(regex)
# only one will survive
if to_rep_re and regex_re:
raise AssertionError(
"only one of to_replace and regex can be regex compilable"
)
# if regex was passed as something that can be a regex (rather than a
# boolean)
if regex_re:
to_replace = regex
regex = regex_re or to_rep_re
# try to get the pattern attribute (compiled re) or it's a string
if is_re(to_replace):
pattern = to_replace.pattern
else:
pattern = to_replace
# if the pattern is not empty and to_replace is either a string or a
# regex
if regex and pattern:
rx = re.compile(to_replace)
else:
# if the thing to replace is not a string or compiled regex call
# the superclass method -> to_replace is some kind of object
return super().replace(
to_replace, value, inplace=inplace, filter=filter, regex=regex
)
new_values = self.values if inplace else self.values.copy()
# deal with replacing values with objects (strings) that match but
# whose replacement is not a string (numeric, nan, object)
if isna(value) or not isinstance(value, str):
def re_replacer(s):
if is_re(rx) and isinstance(s, str):
return value if rx.search(s) is not None else s
else:
return s
else:
# value is guaranteed to be a string here, s can be either a string
# or null if it's null it gets returned
def re_replacer(s):
if is_re(rx) and isinstance(s, str):
return rx.sub(value, s)
else:
return s
f = np.vectorize(re_replacer, otypes=[self.dtype])
if filter is None:
filt = slice(None)
else:
filt = self.mgr_locs.isin(filter).nonzero()[0]
if mask is None:
new_values[filt] = f(new_values[filt])
else:
new_values[filt][mask] = f(new_values[filt][mask])
# convert
block = self.make_block(new_values)
if convert:
block = block.convert(numeric=False)
return block
def _replace_coerce(
self, to_replace, value, inplace=True, regex=False, convert=False, mask=None
):
"""
Replace value corresponding to the given boolean array with another
value.
Parameters
----------
to_replace : object or pattern
Scalar to replace or regular expression to match.
value : object
Replacement object.
inplace : bool, default False
Perform inplace modification.
regex : bool, default False
If true, perform regular expression substitution.
convert : bool, default True
If true, try to coerce any object types to better types.
mask : array-like of bool, optional
True indicate corresponding element is ignored.
Returns
-------
A new block if there is anything to replace or the original block.
"""
if mask.any():
block = super()._replace_coerce(
to_replace=to_replace,
value=value,
inplace=inplace,
regex=regex,
convert=convert,
mask=mask,
)
if convert:
block = [b.convert(numeric=False, copy=True) for b in block]
return block
if convert:
return [self.convert(numeric=False, copy=True)]
return self
class CategoricalBlock(ExtensionBlock):
__slots__ = ()
is_categorical = True
_verify_integrity = True
_can_hold_na = True
_concatenator = staticmethod(concat_categorical)
def __init__(self, values, placement, ndim=None):
# coerce to categorical if we can
values = extract_array(values)
assert isinstance(values, Categorical), type(values)
super().__init__(values, placement=placement, ndim=ndim)
@property
def _holder(self):
return Categorical
def to_native_types(self, slicer=None, na_rep="", quoting=None, **kwargs):
""" convert to our native types format, slicing if desired """
values = self.values
if slicer is not None:
# Categorical is always one dimension
values = values[slicer]
mask = isna(values)
values = np.array(values, dtype="object")
values[mask] = na_rep
# we are expected to return a 2-d ndarray
return values.reshape(1, len(values))
def concat_same_type(self, to_concat, placement=None):
"""
Concatenate list of single blocks of the same type.
Note that this CategoricalBlock._concat_same_type *may* not
return a CategoricalBlock. When the categories in `to_concat`
differ, this will return an object ndarray.
If / when we decide we don't like that behavior:
1. Change Categorical._concat_same_type to use union_categoricals
2. Delete this method.
"""
values = self._concatenator(
[blk.values for blk in to_concat], axis=self.ndim - 1
)
# not using self.make_block_same_class as values can be object dtype
return make_block(
values, placement=placement or slice(0, len(values), 1), ndim=self.ndim
)
def replace(
self,
to_replace,
value,
inplace: bool = False,
filter=None,
regex: bool = False,
convert: bool = True,
):
inplace = validate_bool_kwarg(inplace, "inplace")
result = self if inplace else self.copy()
if filter is None: # replace was called on a series
result.values.replace(to_replace, value, inplace=True)
if convert:
return result.convert(numeric=False, copy=not inplace)
else:
return result
else: # replace was called on a DataFrame
if not isna(value):
result.values.add_categories(value, inplace=True)
return super(CategoricalBlock, result).replace(
to_replace, value, inplace, filter, regex, convert
)
# -----------------------------------------------------------------
# Constructor Helpers
def get_block_type(values, dtype=None):
"""
Find the appropriate Block subclass to use for the given values and dtype.
Parameters
----------
values : ndarray-like
dtype : numpy or pandas dtype
Returns
-------
cls : class, subclass of Block
"""
dtype = dtype or values.dtype
vtype = dtype.type
if is_sparse(dtype):
# Need this first(ish) so that Sparse[datetime] is sparse
cls = ExtensionBlock
elif is_categorical(values):
cls = CategoricalBlock
elif issubclass(vtype, np.datetime64):
assert not is_datetime64tz_dtype(values)
cls = DatetimeBlock
elif is_datetime64tz_dtype(values):
cls = DatetimeTZBlock
elif is_interval_dtype(dtype) or is_period_dtype(dtype):
cls = ObjectValuesExtensionBlock
elif is_extension_array_dtype(values):
cls = ExtensionBlock
elif issubclass(vtype, np.floating):
cls = FloatBlock
elif issubclass(vtype, np.timedelta64):
assert issubclass(vtype, np.integer)
cls = TimeDeltaBlock
elif issubclass(vtype, np.complexfloating):
cls = ComplexBlock
elif issubclass(vtype, np.integer):
cls = IntBlock
elif dtype == np.bool_:
cls = BoolBlock
else:
cls = ObjectBlock
return cls
def make_block(values, placement, klass=None, ndim=None, dtype=None):
# Ensure that we don't allow PandasArray / PandasDtype in internals.
# For now, blocks should be backed by ndarrays when possible.
if isinstance(values, ABCPandasArray):
values = values.to_numpy()
if ndim and ndim > 1:
values = np.atleast_2d(values)
if isinstance(dtype, PandasDtype):
dtype = dtype.numpy_dtype
if klass is None:
dtype = dtype or values.dtype
klass = get_block_type(values, dtype)
elif klass is DatetimeTZBlock and not is_datetime64tz_dtype(values):
# TODO: This is no longer hit internally; does it need to be retained
# for e.g. pyarrow?
values = DatetimeArray._simple_new(values, dtype=dtype)
return klass(values, ndim=ndim, placement=placement)
# -----------------------------------------------------------------
def _extend_blocks(result, blocks=None):
""" return a new extended blocks, given the result """
if blocks is None:
blocks = []
if isinstance(result, list):
for r in result:
if isinstance(r, list):
blocks.extend(r)
else:
blocks.append(r)
else:
assert isinstance(result, Block), type(result)
blocks.append(result)
return blocks
def _block_shape(values, ndim=1, shape=None):
""" guarantee the shape of the values to be at least 1 d """
if values.ndim < ndim:
if shape is None:
shape = values.shape
if not is_extension_array_dtype(values):
# TODO: https://github.com/pandas-dev/pandas/issues/23023
# block.shape is incorrect for "2D" ExtensionArrays
# We can't, and don't need to, reshape.
values = values.reshape(tuple((1,) + shape))
return values
def _merge_blocks(blocks, dtype=None, _can_consolidate=True):
if len(blocks) == 1:
return blocks[0]
if _can_consolidate:
if dtype is None:
if len({b.dtype for b in blocks}) != 1:
raise AssertionError("_merge_blocks are invalid!")
# FIXME: optimization potential in case all mgrs contain slices and
# combination of those slices is a slice, too.
new_mgr_locs = np.concatenate([b.mgr_locs.as_array for b in blocks])
new_values = np.vstack([b.values for b in blocks])
argsort = np.argsort(new_mgr_locs)
new_values = new_values[argsort]
new_mgr_locs = new_mgr_locs[argsort]
return make_block(new_values, placement=new_mgr_locs)
# no merge
return blocks
def _safe_reshape(arr, new_shape):
"""
If possible, reshape `arr` to have shape `new_shape`,
with a couple of exceptions (see gh-13012):
1) If `arr` is a ExtensionArray or Index, `arr` will be
returned as is.
2) If `arr` is a Series, the `_values` attribute will
be reshaped and returned.
Parameters
----------
arr : array-like, object to be reshaped
new_shape : int or tuple of ints, the new shape
"""
if isinstance(arr, ABCSeries):
arr = arr._values
if not isinstance(arr, ABCExtensionArray):
arr = arr.reshape(new_shape)
return arr
def _putmask_smart(v: np.ndarray, mask: np.ndarray, n) -> np.ndarray:
"""
Return a new ndarray, try to preserve dtype if possible.
Parameters
----------
v : np.ndarray
`values`, updated in-place.
mask : np.ndarray[bool]
Applies to both sides (array like).
n : `new values` either scalar or an array like aligned with `values`
Returns
-------
values : ndarray with updated values
this *may* be a copy of the original
See Also
--------
ndarray.putmask
"""
# we cannot use np.asarray() here as we cannot have conversions
# that numpy does when numeric are mixed with strings
# n should be the length of the mask or a scalar here
if not is_list_like(n):
n = np.repeat(n, len(mask))
# see if we are only masking values that if putted
# will work in the current dtype
try:
nn = n[mask]
except TypeError:
# TypeError: only integer scalar arrays can be converted to a scalar index
pass
else:
# make sure that we have a nullable type
# if we have nulls
if not _isna_compat(v, nn[0]):
pass
elif not (is_float_dtype(nn.dtype) or is_integer_dtype(nn.dtype)):
# only compare integers/floats
pass
elif not (is_float_dtype(v.dtype) or is_integer_dtype(v.dtype)):
# only compare integers/floats
pass
else:
# we ignore ComplexWarning here
with warnings.catch_warnings(record=True):
warnings.simplefilter("ignore", np.ComplexWarning)
nn_at = nn.astype(v.dtype)
comp = nn == nn_at
if is_list_like(comp) and comp.all():
nv = v.copy()
nv[mask] = nn_at
return nv
n = np.asarray(n)
def _putmask_preserve(nv, n):
try:
nv[mask] = n[mask]
except (IndexError, ValueError):
nv[mask] = n
return nv
# preserves dtype if possible
if v.dtype.kind == n.dtype.kind:
return _putmask_preserve(v, n)
# change the dtype if needed
dtype, _ = maybe_promote(n.dtype)
v = v.astype(dtype)
return _putmask_preserve(v, n)
from datetime import datetime, timedelta
import functools
import inspect
import re
from typing import Any, List
import warnings
import numpy as np
from pandas._libs import NaT, Timestamp, algos as libalgos, lib, tslib, writers
import pandas._libs.internals as libinternals
from pandas._libs.tslibs import Timedelta, conversion
from pandas._libs.tslibs.timezones import tz_compare
from pandas._typing import ArrayLike
from pandas.util._validators import validate_bool_kwarg
from pandas.core.dtypes.cast import (
astype_nansafe,
convert_scalar_for_putitemlike,
find_common_type,
infer_dtype_from,
infer_dtype_from_scalar,
maybe_downcast_numeric,
maybe_downcast_to_dtype,
maybe_infer_dtype_type,
maybe_promote,
maybe_upcast,
soft_convert_objects,
)
from pandas.core.dtypes.common import (
_NS_DTYPE,
_TD_DTYPE,
is_bool_dtype,
is_categorical,
is_categorical_dtype,
is_datetime64_dtype,
is_datetime64tz_dtype,
is_dtype_equal,
is_extension_array_dtype,
is_float_dtype,
is_integer,
is_integer_dtype,
is_interval_dtype,
is_list_like,
is_object_dtype,
is_period_dtype,
is_re,
is_re_compilable,
is_sparse,
is_timedelta64_dtype,
pandas_dtype,
)
from pandas.core.dtypes.concat import concat_categorical, concat_datetime
from pandas.core.dtypes.dtypes import CategoricalDtype, ExtensionDtype
from pandas.core.dtypes.generic import (
ABCDataFrame,
ABCExtensionArray,
ABCPandasArray,
ABCSeries,
)
from pandas.core.dtypes.missing import (
_isna_compat,
array_equivalent,
is_valid_nat_for_dtype,
isna,
)
import pandas.core.algorithms as algos
from pandas.core.array_algos.transforms import shift
from pandas.core.arrays import (
Categorical,
DatetimeArray,
ExtensionArray,
PandasArray,
PandasDtype,
TimedeltaArray,
)
from pandas.core.base import PandasObject
import pandas.core.common as com
from pandas.core.construction import extract_array
from pandas.core.indexers import (
check_setitem_lengths,
is_empty_indexer,
is_scalar_indexer,
)
import pandas.core.missing as missing
from pandas.core.nanops import nanpercentile
class Block(PandasObject):
"""
Canonical n-dimensional unit of homogeneous dtype contained in a pandas
data structure
Index-ignorant; let the container take care of that
"""
__slots__ = ["_mgr_locs", "values", "ndim"]
is_numeric = False
is_float = False
is_integer = False
is_complex = False
is_datetime = False
is_datetimetz = False
is_timedelta = False
is_bool = False
is_object = False
is_categorical = False
is_extension = False
_can_hold_na = False
_can_consolidate = True
_verify_integrity = True
_validate_ndim = True
_concatenator = staticmethod(np.concatenate)
def __init__(self, values, placement, ndim=None):
self.ndim = self._check_ndim(values, ndim)
self.mgr_locs = placement
self.values = values
if self._validate_ndim and self.ndim and len(self.mgr_locs) != len(self.values):
raise ValueError(
f"Wrong number of items passed {len(self.values)}, "
f"placement implies {len(self.mgr_locs)}"
)
def _check_ndim(self, values, ndim):
"""
ndim inference and validation.
Infers ndim from 'values' if not provided to __init__.
Validates that values.ndim and ndim are consistent if and only if
the class variable '_validate_ndim' is True.
Parameters
----------
values : array-like
ndim : int or None
Returns
-------
ndim : int
Raises
------
ValueError : the number of dimensions do not match
"""
if ndim is None:
ndim = values.ndim
if self._validate_ndim and values.ndim != ndim:
raise ValueError(
"Wrong number of dimensions. "
f"values.ndim != ndim [{values.ndim} != {ndim}]"
)
return ndim
@property
def _holder(self):
"""
The array-like that can hold the underlying values.
None for 'Block', overridden by subclasses that don't
use an ndarray.
"""
return None
@property
def _consolidate_key(self):
return (self._can_consolidate, self.dtype.name)
@property
def _is_single_block(self) -> bool:
return self.ndim == 1
@property
def is_view(self) -> bool:
""" return a boolean if I am possibly a view """
return self.values.base is not None
@property
def is_datelike(self) -> bool:
""" return True if I am a non-datelike """
return self.is_datetime or self.is_timedelta
def is_categorical_astype(self, dtype) -> bool:
"""
validate that we have a astypeable to categorical,
returns a boolean if we are a categorical
"""
if dtype is Categorical or dtype is CategoricalDtype:
# this is a pd.Categorical, but is not
# a valid type for astypeing
raise TypeError(f"invalid type {dtype} for astype")
elif is_categorical_dtype(dtype):
return True
return False
def external_values(self):
"""
The array that Series.values returns (public attribute).
This has some historical constraints, and is overridden in block
subclasses to return the correct array (e.g. period returns
object ndarray and datetimetz a datetime64[ns] ndarray instead of
proper extension array).
"""
return self.values
def internal_values(self):
"""
The array that Series._values returns (internal values).
"""
return self.values
def array_values(self) -> ExtensionArray:
"""
The array that Series.array returns. Always an ExtensionArray.
"""
return PandasArray(self.values)
def get_values(self, dtype=None):
"""
return an internal format, currently just the ndarray
this is often overridden to handle to_dense like operations
"""
if is_object_dtype(dtype):
return self.values.astype(object)
return self.values
def get_block_values_for_json(self) -> np.ndarray:
"""
This is used in the JSON C code.
"""
# TODO(2DEA): reshape will be unnecessary with 2D EAs
return np.asarray(self.values).reshape(self.shape)
@property
def fill_value(self):
return np.nan
@property
def mgr_locs(self):
return self._mgr_locs
@mgr_locs.setter
def mgr_locs(self, new_mgr_locs):
if not isinstance(new_mgr_locs, libinternals.BlockPlacement):
new_mgr_locs = libinternals.BlockPlacement(new_mgr_locs)
self._mgr_locs = new_mgr_locs
def make_block(self, values, placement=None) -> "Block":
"""
Create a new block, with type inference propagate any values that are
not specified
"""
if placement is None:
placement = self.mgr_locs
return make_block(values, placement=placement, ndim=self.ndim)
def make_block_same_class(self, values, placement=None, ndim=None):
""" Wrap given values in a block of same type as self. """
if placement is None:
placement = self.mgr_locs
if ndim is None:
ndim = self.ndim
return make_block(values, placement=placement, ndim=ndim, klass=type(self))
def __repr__(self) -> str:
# don't want to print out all of the items here
name = type(self).__name__
if self._is_single_block:
result = f"{name}: {len(self)} dtype: {self.dtype}"
else:
shape = " x ".join(str(s) for s in self.shape)
result = f"{name}: {self.mgr_locs.indexer}, {shape}, dtype: {self.dtype}"
return result
def __len__(self) -> int:
return len(self.values)
def __getstate__(self):
return self.mgr_locs.indexer, self.values
def __setstate__(self, state):
self.mgr_locs = libinternals.BlockPlacement(state[0])
self.values = state[1]
self.ndim = self.values.ndim
def _slice(self, slicer):
""" return a slice of my values """
return self.values[slicer]
def getitem_block(self, slicer, new_mgr_locs=None):
"""
Perform __getitem__-like, return result as block.
As of now, only supports slices that preserve dimensionality.
"""
if new_mgr_locs is None:
axis0_slicer = slicer[0] if isinstance(slicer, tuple) else slicer
new_mgr_locs = self.mgr_locs[axis0_slicer]
new_values = self._slice(slicer)
if self._validate_ndim and new_values.ndim != self.ndim:
raise ValueError("Only same dim slicing is allowed")
return self.make_block_same_class(new_values, new_mgr_locs)
@property
def shape(self):
return self.values.shape
@property
def dtype(self):
return self.values.dtype
def merge(self, other):
return _merge_blocks([self, other])
def concat_same_type(self, to_concat, placement=None):
"""
Concatenate list of single blocks of the same type.
"""
values = self._concatenator(
[blk.values for blk in to_concat], axis=self.ndim - 1
)
return self.make_block_same_class(
values, placement=placement or slice(0, len(values), 1)
)
def iget(self, i):
return self.values[i]
def set(self, locs, values):
"""
Modify block values in-place with new item value.
Notes
-----
`set` never creates a new array or new Block, whereas `setitem` _may_
create a new array and always creates a new Block.
"""
self.values[locs] = values
def delete(self, loc) -> None:
"""
Delete given loc(-s) from block in-place.
"""
self.values = np.delete(self.values, loc, 0)
self.mgr_locs = self.mgr_locs.delete(loc)
def apply(self, func, **kwargs) -> List["Block"]:
"""
apply the function to my values; return a block if we are not
one
"""
with np.errstate(all="ignore"):
result = func(self.values, **kwargs)
return self._split_op_result(result)
def _split_op_result(self, result) -> List["Block"]:
# See also: split_and_operate
if is_extension_array_dtype(result) and result.ndim > 1:
# if we get a 2D ExtensionArray, we need to split it into 1D pieces
nbs = []
for i, loc in enumerate(self.mgr_locs):
vals = result[i]
nv = _block_shape(vals, ndim=self.ndim)
block = self.make_block(values=nv, placement=[loc])
nbs.append(block)
return nbs
if not isinstance(result, Block):
result = self.make_block(values=_block_shape(result, ndim=self.ndim))
return [result]
def fillna(
self, value, limit=None, inplace: bool = False, downcast=None
) -> List["Block"]:
"""
fillna on the block with the value. If we fail, then convert to
ObjectBlock and try again
"""
inplace = validate_bool_kwarg(inplace, "inplace")
mask = isna(self.values)
if limit is not None:
limit = libalgos._validate_limit(None, limit=limit)
mask[mask.cumsum(self.ndim - 1) > limit] = False
if not self._can_hold_na:
if inplace:
return [self]
else:
return [self.copy()]
if self._can_hold_element(value):
# equivalent: _try_coerce_args(value) would not raise
blocks = self.putmask(mask, value, inplace=inplace)
return self._maybe_downcast(blocks, downcast)
# we can't process the value, but nothing to do
if not mask.any():
return [self] if inplace else [self.copy()]
# operate column-by-column
def f(mask, val, idx):
block = self.coerce_to_target_dtype(value)
# slice out our block
if idx is not None:
# i.e. self.ndim == 2
block = block.getitem_block(slice(idx, idx + 1))
return block.fillna(value, limit=limit, inplace=inplace, downcast=None)
return self.split_and_operate(None, f, inplace)
def split_and_operate(self, mask, f, inplace: bool) -> List["Block"]:
"""
split the block per-column, and apply the callable f
per-column, return a new block for each. Handle
masking which will not change a block unless needed.
Parameters
----------
mask : 2-d boolean mask
f : callable accepting (1d-mask, 1d values, indexer)
inplace : boolean
Returns
-------
list of blocks
"""
if mask is None:
mask = np.broadcast_to(True, shape=self.shape)
new_values = self.values
def make_a_block(nv, ref_loc):
if isinstance(nv, list):
assert len(nv) == 1, nv
assert isinstance(nv[0], Block)
block = nv[0]
else:
# Put back the dimension that was taken from it and make
# a block out of the result.
nv = _block_shape(nv, ndim=self.ndim)
block = self.make_block(values=nv, placement=ref_loc)
return block
# ndim == 1
if self.ndim == 1:
if mask.any():
nv = f(mask, new_values, None)
else:
nv = new_values if inplace else new_values.copy()
block = make_a_block(nv, self.mgr_locs)
return [block]
# ndim > 1
new_blocks = []
for i, ref_loc in enumerate(self.mgr_locs):
m = mask[i]
v = new_values[i]
# need a new block
if m.any():
nv = f(m, v, i)
else:
nv = v if inplace else v.copy()
block = make_a_block(nv, [ref_loc])
new_blocks.append(block)
return new_blocks
def _maybe_downcast(self, blocks: List["Block"], downcast=None) -> List["Block"]:
# no need to downcast our float
# unless indicated
if downcast is None and (
self.is_float or self.is_timedelta or self.is_datetime
):
return blocks
return _extend_blocks([b.downcast(downcast) for b in blocks])
def downcast(self, dtypes=None):
""" try to downcast each item to the dict of dtypes if present """
# turn it off completely
if dtypes is False:
return self
values = self.values
# single block handling
if self._is_single_block:
# try to cast all non-floats here
if dtypes is None:
dtypes = "infer"
nv = maybe_downcast_to_dtype(values, dtypes)
return self.make_block(nv)
# ndim > 1
if dtypes is None:
return self
if not (dtypes == "infer" or isinstance(dtypes, dict)):
raise ValueError(
"downcast must have a dictionary or 'infer' as its argument"
)
elif dtypes != "infer":
raise AssertionError("dtypes as dict is not supported yet")
# operate column-by-column
# this is expensive as it splits the blocks items-by-item
def f(mask, val, idx):
val = maybe_downcast_to_dtype(val, dtype="infer")
return val
return self.split_and_operate(None, f, False)
def astype(self, dtype, copy: bool = False, errors: str = "raise"):
"""
Coerce to the new dtype.
Parameters
----------
dtype : str, dtype convertible
copy : bool, default False
copy if indicated
errors : str, {'raise', 'ignore'}, default 'ignore'
- ``raise`` : allow exceptions to be raised
- ``ignore`` : suppress exceptions. On error return original object
Returns
-------
Block
"""
errors_legal_values = ("raise", "ignore")
if errors not in errors_legal_values:
invalid_arg = (
"Expected value of kwarg 'errors' to be one of "
f"{list(errors_legal_values)}. Supplied value is '{errors}'"
)
raise ValueError(invalid_arg)
if inspect.isclass(dtype) and issubclass(dtype, ExtensionDtype):
msg = (
f"Expected an instance of {dtype.__name__}, "
"but got the class instead. Try instantiating 'dtype'."
)
raise TypeError(msg)
# may need to convert to categorical
if self.is_categorical_astype(dtype):
if is_categorical_dtype(self.values):
# GH 10696/18593: update an existing categorical efficiently
return self.make_block(self.values.astype(dtype, copy=copy))
return self.make_block(Categorical(self.values, dtype=dtype))
dtype = pandas_dtype(dtype)
# astype processing
if is_dtype_equal(self.dtype, dtype):
if copy:
return self.copy()
return self
# force the copy here
if self.is_extension:
# TODO: Should we try/except this astype?
values = self.values.astype(dtype)
else:
if issubclass(dtype.type, str):
# use native type formatting for datetime/tz/timedelta
if self.is_datelike:
values = self.to_native_types()
# astype formatting
else:
# Because we have neither is_extension nor is_datelike,
# self.values already has the correct shape
values = self.values
else:
values = self.get_values(dtype=dtype)
# _astype_nansafe works fine with 1-d only
vals1d = values.ravel()
try:
values = astype_nansafe(vals1d, dtype, copy=True)
except (ValueError, TypeError):
# e.g. astype_nansafe can fail on object-dtype of strings
# trying to convert to float
if errors == "raise":
raise
newb = self.copy() if copy else self
return newb
# TODO(extension)
# should we make this attribute?
if isinstance(values, np.ndarray):
values = values.reshape(self.shape)
newb = make_block(values, placement=self.mgr_locs, ndim=self.ndim)
if newb.is_numeric and self.is_numeric:
if newb.shape != self.shape:
raise TypeError(
f"cannot set astype for copy = [{copy}] for dtype "
f"({self.dtype.name} [{self.shape}]) to different shape "
f"({newb.dtype.name} [{newb.shape}])"
)
return newb
def convert(
self,
copy: bool = True,
datetime: bool = True,
numeric: bool = True,
timedelta: bool = True,
coerce: bool = False,
):
"""
attempt to coerce any object types to better types return a copy
of the block (if copy = True) by definition we are not an ObjectBlock
here!
"""
return self.copy() if copy else self
def _can_hold_element(self, element: Any) -> bool:
""" require the same dtype as ourselves """
dtype = self.values.dtype.type
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return issubclass(tipo.type, dtype)
return isinstance(element, dtype)
def to_native_types(self, slicer=None, na_rep="nan", quoting=None, **kwargs):
""" convert to our native types format, slicing if desired """
values = self.values
if slicer is not None:
values = values[:, slicer]
mask = isna(values)
itemsize = writers.word_len(na_rep)
if not self.is_object and not quoting and itemsize:
values = values.astype(str)
if values.dtype.itemsize / np.dtype("U1").itemsize < itemsize:
# enlarge for the na_rep
values = values.astype(f"<U{itemsize}")
else:
values = np.array(values, dtype="object")
values[mask] = na_rep
return values
# block actions #
def copy(self, deep: bool = True):
""" copy constructor """
values = self.values
if deep:
values = values.copy()
return self.make_block_same_class(values, ndim=self.ndim)
def replace(
self,
to_replace,
value,
inplace: bool = False,
filter=None,
regex: bool = False,
convert: bool = True,
):
"""
replace the to_replace value with value, possible to create new
blocks here this is just a call to putmask. regex is not used here.
It is used in ObjectBlocks. It is here for API compatibility.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
original_to_replace = to_replace
# If we cannot replace with own dtype, convert to ObjectBlock and
# retry
if not self._can_hold_element(to_replace):
if not isinstance(to_replace, list):
if inplace:
return [self]
return [self.copy()]
to_replace = [x for x in to_replace if self._can_hold_element(x)]
if not len(to_replace):
# GH#28084 avoid costly checks since we can infer
# that there is nothing to replace in this block
if inplace:
return [self]
return [self.copy()]
if len(to_replace) == 1:
# _can_hold_element checks have reduced this back to the
# scalar case and we can avoid a costly object cast
return self.replace(
to_replace[0],
value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
# GH 22083, TypeError or ValueError occurred within error handling
# causes infinite loop. Cast and retry only if not objectblock.
if is_object_dtype(self):
raise AssertionError
# try again with a compatible block
block = self.astype(object)
return block.replace(
to_replace=to_replace,
value=value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
values = self.values
if lib.is_scalar(to_replace) and isinstance(values, np.ndarray):
# The only non-DatetimeLike class that also has a non-trivial
# try_coerce_args is ObjectBlock, but that overrides replace,
# so does not get here.
to_replace = convert_scalar_for_putitemlike(to_replace, values.dtype)
mask = missing.mask_missing(values, to_replace)
if filter is not None:
filtered_out = ~self.mgr_locs.isin(filter)
mask[filtered_out.nonzero()[0]] = False
if not mask.any():
if inplace:
return [self]
return [self.copy()]
try:
blocks = self.putmask(mask, value, inplace=inplace)
# Note: it is _not_ the case that self._can_hold_element(value)
# is always true at this point. In particular, that can fail
# for:
# "2u" with bool-dtype, float-dtype
# 0.5 with int64-dtype
# np.nan with int64-dtype
except (TypeError, ValueError):
# GH 22083, TypeError or ValueError occurred within error handling
# causes infinite loop. Cast and retry only if not objectblock.
if is_object_dtype(self):
raise
assert not self._can_hold_element(value), value
# try again with a compatible block
block = self.astype(object)
return block.replace(
to_replace=original_to_replace,
value=value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
if convert:
blocks = [b.convert(numeric=False, copy=not inplace) for b in blocks]
return blocks
def _replace_single(self, *args, **kwargs):
""" no-op on a non-ObjectBlock """
return self if kwargs["inplace"] else self.copy()
def setitem(self, indexer, value):
"""
Attempt self.values[indexer] = value, possibly creating a new array.
Parameters
----------
indexer : tuple, list-like, array-like, slice
The subset of self.values to set
value : object
The value being set
Returns
-------
Block
Notes
-----
`indexer` is a direct slice/positional indexer. `value` must
be a compatible shape.
"""
transpose = self.ndim == 2
if isinstance(indexer, np.ndarray) and indexer.ndim > self.ndim:
raise ValueError(f"Cannot set values with ndim > {self.ndim}")
# coerce None values, if appropriate
if value is None:
if self.is_numeric:
value = np.nan
# coerce if block dtype can store value
values = self.values
if self._can_hold_element(value):
# We only get here for non-Extension Blocks, so _try_coerce_args
# is only relevant for DatetimeBlock and TimedeltaBlock
if lib.is_scalar(value):
value = convert_scalar_for_putitemlike(value, values.dtype)
else:
# current dtype cannot store value, coerce to common dtype
find_dtype = False
if hasattr(value, "dtype"):
dtype = value.dtype
find_dtype = True
elif lib.is_scalar(value) and not isna(value):
dtype, _ = infer_dtype_from_scalar(value, pandas_dtype=True)
find_dtype = True
if find_dtype:
dtype = find_common_type([values.dtype, dtype])
if not is_dtype_equal(self.dtype, dtype):
b = self.astype(dtype)
return b.setitem(indexer, value)
# value must be storeable at this moment
if is_extension_array_dtype(getattr(value, "dtype", None)):
# We need to be careful not to allow through strings that
# can be parsed to EADtypes
arr_value = value
else:
arr_value = np.array(value)
# cast the values to a type that can hold nan (if necessary)
if not self._can_hold_element(value):
dtype, _ = maybe_promote(arr_value.dtype)
values = values.astype(dtype)
if transpose:
values = values.T
# length checking
check_setitem_lengths(indexer, value, values)
exact_match = (
len(arr_value.shape)
and arr_value.shape[0] == values.shape[0]
and arr_value.size == values.size
)
if is_empty_indexer(indexer, arr_value):
# GH#8669 empty indexers
pass
elif is_scalar_indexer(indexer, self.ndim):
# setting a single element for each dim and with a rhs that could
# be e.g. a list; see GH#6043
values[indexer] = value
elif (
exact_match
and is_categorical_dtype(arr_value.dtype)
and not is_categorical_dtype(values)
):
# GH25495 - If the current dtype is not categorical,
# we need to create a new categorical block
values[indexer] = value
return self.make_block(Categorical(self.values, dtype=arr_value.dtype))
# if we are an exact match (ex-broadcasting),
# then use the resultant dtype
elif exact_match:
# We are setting _all_ of the array's values, so can cast to new dtype
values[indexer] = value
values = values.astype(arr_value.dtype, copy=False)
# set
else:
values[indexer] = value
if transpose:
values = values.T
block = self.make_block(values)
return block
def putmask(
self,
mask,
new,
align: bool = True,
inplace: bool = False,
axis: int = 0,
transpose: bool = False,
):
"""
putmask the data to the block; it is possible that we may create a
new dtype of block
return the resulting block(s)
Parameters
----------
mask : the condition to respect
new : a ndarray/object
align : boolean, perform alignment on other/cond, default is True
inplace : perform inplace modification, default is False
axis : int
transpose : boolean
Set to True if self is stored with axes reversed
Returns
-------
a list of new blocks, the result of the putmask
"""
new_values = self.values if inplace else self.values.copy()
new = getattr(new, "values", new)
mask = getattr(mask, "values", mask)
# if we are passed a scalar None, convert it here
if not is_list_like(new) and isna(new) and not self.is_object:
# FIXME: make sure we have compatible NA
new = self.fill_value
if self._can_hold_element(new):
# We only get here for non-Extension Blocks, so _try_coerce_args
# is only relevant for DatetimeBlock and TimedeltaBlock
if lib.is_scalar(new):
new = convert_scalar_for_putitemlike(new, new_values.dtype)
if transpose:
new_values = new_values.T
# If the default repeat behavior in np.putmask would go in the
# wrong direction, then explicitly repeat and reshape new instead
if getattr(new, "ndim", 0) >= 1:
if self.ndim - 1 == new.ndim and axis == 1:
new = np.repeat(new, new_values.shape[-1]).reshape(self.shape)
new = new.astype(new_values.dtype)
# we require exact matches between the len of the
# values we are setting (or is compat). np.putmask
# doesn't check this and will simply truncate / pad
# the output, but we want sane error messages
#
# TODO: this prob needs some better checking
# for 2D cases
if (
is_list_like(new)
and np.any(mask[mask])
and getattr(new, "ndim", 1) == 1
):
if mask[mask].shape[-1] == len(new):
# GH 30567
# If length of ``new`` is less than the length of ``new_values``,
# `np.putmask` would first repeat the ``new`` array and then
# assign the masked values hence produces incorrect result.
# `np.place` on the other hand uses the ``new`` values at it is
# to place in the masked locations of ``new_values``
np.place(new_values, mask, new)
elif mask.shape[-1] == len(new) or len(new) == 1:
np.putmask(new_values, mask, new)
else:
raise ValueError("cannot assign mismatch length to masked array")
else:
np.putmask(new_values, mask, new)
# maybe upcast me
elif mask.any():
if transpose:
mask = mask.T
if isinstance(new, np.ndarray):
new = new.T
axis = new_values.ndim - axis - 1
# Pseudo-broadcast
if getattr(new, "ndim", 0) >= 1:
if self.ndim - 1 == new.ndim:
new_shape = list(new.shape)
new_shape.insert(axis, 1)
new = new.reshape(tuple(new_shape))
# operate column-by-column
def f(mask, val, idx):
if idx is None:
# ndim==1 case.
n = new
else:
if isinstance(new, np.ndarray):
n = np.squeeze(new[idx % new.shape[0]])
else:
n = np.array(new)
# type of the new block
dtype, _ = maybe_promote(n.dtype)
# we need to explicitly astype here to make a copy
n = n.astype(dtype)
nv = _putmask_smart(val, mask, n)
return nv
new_blocks = self.split_and_operate(mask, f, inplace)
return new_blocks
if inplace:
return [self]
if transpose:
new_values = new_values.T
return [self.make_block(new_values)]
def coerce_to_target_dtype(self, other):
"""
coerce the current block to a dtype compat for other
we will return a block, possibly object, and not raise
we can also safely try to coerce to the same dtype
and will receive the same block
"""
# if we cannot then coerce to object
dtype, _ = infer_dtype_from(other, pandas_dtype=True)
if is_dtype_equal(self.dtype, dtype):
return self
if self.is_bool or is_object_dtype(dtype) or is_bool_dtype(dtype):
# we don't upcast to bool
return self.astype(object)
elif (self.is_float or self.is_complex) and (
is_integer_dtype(dtype) or is_float_dtype(dtype)
):
# don't coerce float/complex to int
return self
elif (
self.is_datetime
or is_datetime64_dtype(dtype)
or is_datetime64tz_dtype(dtype)
):
# not a datetime
if not (
(is_datetime64_dtype(dtype) or is_datetime64tz_dtype(dtype))
and self.is_datetime
):
return self.astype(object)
# don't upcast timezone with different timezone or no timezone
mytz = getattr(self.dtype, "tz", None)
othertz = getattr(dtype, "tz", None)
if not tz_compare(mytz, othertz):
return self.astype(object)
raise AssertionError(
f"possible recursion in coerce_to_target_dtype: {self} {other}"
)
elif self.is_timedelta or is_timedelta64_dtype(dtype):
# not a timedelta
if not (is_timedelta64_dtype(dtype) and self.is_timedelta):
return self.astype(object)
raise AssertionError(
f"possible recursion in coerce_to_target_dtype: {self} {other}"
)
try:
return self.astype(dtype)
except (ValueError, TypeError, OverflowError):
return self.astype(object)
def interpolate(
self,
method="pad",
axis=0,
index=None,
inplace=False,
limit=None,
limit_direction="forward",
limit_area=None,
fill_value=None,
coerce=False,
downcast=None,
**kwargs,
):
inplace = validate_bool_kwarg(inplace, "inplace")
def check_int_bool(self, inplace):
# Only FloatBlocks will contain NaNs.
# timedelta subclasses IntBlock
if (self.is_bool or self.is_integer) and not self.is_timedelta:
if inplace:
return self
else:
return self.copy()
# a fill na type method
try:
m = missing.clean_fill_method(method)
except ValueError:
m = None
if m is not None:
r = check_int_bool(self, inplace)
if r is not None:
return r
return self._interpolate_with_fill(
method=m,
axis=axis,
inplace=inplace,
limit=limit,
fill_value=fill_value,
coerce=coerce,
downcast=downcast,
)
# validate the interp method
m = missing.clean_interp_method(method, **kwargs)
r = check_int_bool(self, inplace)
if r is not None:
return r
return self._interpolate(
method=m,
index=index,
axis=axis,
limit=limit,
limit_direction=limit_direction,
limit_area=limit_area,
fill_value=fill_value,
inplace=inplace,
downcast=downcast,
**kwargs,
)
def _interpolate_with_fill(
self,
method="pad",
axis=0,
inplace=False,
limit=None,
fill_value=None,
coerce=False,
downcast=None,
) -> List["Block"]:
""" fillna but using the interpolate machinery """
inplace = validate_bool_kwarg(inplace, "inplace")
# if we are coercing, then don't force the conversion
# if the block can't hold the type
if coerce:
if not self._can_hold_na:
if inplace:
return [self]
else:
return [self.copy()]
values = self.values if inplace else self.values.copy()
# We only get here for non-ExtensionBlock
fill_value = convert_scalar_for_putitemlike(fill_value, self.values.dtype)
values = missing.interpolate_2d(
values,
method=method,
axis=axis,
limit=limit,
fill_value=fill_value,
dtype=self.dtype,
)
blocks = [self.make_block_same_class(values, ndim=self.ndim)]
return self._maybe_downcast(blocks, downcast)
def _interpolate(
self,
method=None,
index=None,
fill_value=None,
axis=0,
limit=None,
limit_direction="forward",
limit_area=None,
inplace=False,
downcast=None,
**kwargs,
) -> List["Block"]:
""" interpolate using scipy wrappers """
inplace = validate_bool_kwarg(inplace, "inplace")
data = self.values if inplace else self.values.copy()
# only deal with floats
if not self.is_float:
if not self.is_integer:
return [self]
data = data.astype(np.float64)
if fill_value is None:
fill_value = self.fill_value
if method in ("krogh", "piecewise_polynomial", "pchip"):
if not index.is_monotonic:
raise ValueError(
f"{method} interpolation requires that the index be monotonic."
)
# process 1-d slices in the axis direction
def func(x):
# process a 1-d slice, returning it
# should the axis argument be handled below in apply_along_axis?
# i.e. not an arg to missing.interpolate_1d
return missing.interpolate_1d(
index,
x,
method=method,
limit=limit,
limit_direction=limit_direction,
limit_area=limit_area,
fill_value=fill_value,
bounds_error=False,
**kwargs,
)
# interp each column independently
interp_values = np.apply_along_axis(func, axis, data)
blocks = [self.make_block_same_class(interp_values)]
return self._maybe_downcast(blocks, downcast)
def take_nd(self, indexer, axis: int, new_mgr_locs=None, fill_tuple=None):
"""
Take values according to indexer and return them as a block.bb
"""
# algos.take_nd dispatches for DatetimeTZBlock, CategoricalBlock
# so need to preserve types
# sparse is treated like an ndarray, but needs .get_values() shaping
values = self.values
if fill_tuple is None:
fill_value = self.fill_value
allow_fill = False
else:
fill_value = fill_tuple[0]
allow_fill = True
new_values = algos.take_nd(
values, indexer, axis=axis, allow_fill=allow_fill, fill_value=fill_value
)
# Called from three places in managers, all of which satisfy
# this assertion
assert not (axis == 0 and new_mgr_locs is None)
if new_mgr_locs is None:
new_mgr_locs = self.mgr_locs
if not is_dtype_equal(new_values.dtype, self.dtype):
return self.make_block(new_values, new_mgr_locs)
else:
return self.make_block_same_class(new_values, new_mgr_locs)
def diff(self, n: int, axis: int = 1) -> List["Block"]:
""" return block for the diff of the values """
new_values = algos.diff(self.values, n, axis=axis, stacklevel=7)
# We use block_shape for ExtensionBlock subclasses, which may call here
# via a super.
new_values = _block_shape(new_values, ndim=self.ndim)
return [self.make_block(values=new_values)]
def shift(self, periods, axis: int = 0, fill_value=None):
""" shift the block by periods, possibly upcast """
# convert integer to float if necessary. need to do a lot more than
# that, handle boolean etc also
new_values, fill_value = maybe_upcast(self.values, fill_value)
new_values = shift(new_values, periods, axis, fill_value)
return [self.make_block(new_values)]
def where(
self,
other,
cond,
align: bool = True,
errors="raise",
try_cast: bool = False,
axis: int = 0,
) -> List["Block"]:
"""
evaluate the block; return result block(s) from the result
Parameters
----------
other : a ndarray/object
cond : the condition to respect
align : bool, default True
Perform alignment on other/cond.
errors : str, {'raise', 'ignore'}, default 'raise'
- ``raise`` : allow exceptions to be raised
- ``ignore`` : suppress exceptions. On error return original object
axis : int, default 0
Returns
-------
a new block(s), the result of the func
"""
import pandas.core.computation.expressions as expressions
assert errors in ["raise", "ignore"]
transpose = self.ndim == 2
values = self.values
orig_other = other
if transpose:
values = values.T
other = getattr(other, "_values", getattr(other, "values", other))
cond = getattr(cond, "values", cond)
# If the default broadcasting would go in the wrong direction, then
# explicitly reshape other instead
if getattr(other, "ndim", 0) >= 1:
if values.ndim - 1 == other.ndim and axis == 1:
other = other.reshape(tuple(other.shape + (1,)))
elif transpose and values.ndim == self.ndim - 1:
cond = cond.T
if not hasattr(cond, "shape"):
raise ValueError("where must have a condition that is ndarray like")
def where_func(cond, values, other):
if not (
(self.is_integer or self.is_bool)
and lib.is_float(other)
and np.isnan(other)
):
# np.where will cast integer array to floats in this case
if not self._can_hold_element(other):
raise TypeError
if lib.is_scalar(other) and isinstance(values, np.ndarray):
# convert datetime to datetime64, timedelta to timedelta64
other = convert_scalar_for_putitemlike(other, values.dtype)
# By the time we get here, we should have all Series/Index
# args extracted to ndarray
fastres = expressions.where(cond, values, other)
return fastres
if cond.ravel().all():
result = values
else:
# see if we can operate on the entire block, or need item-by-item
# or if we are a single block (ndim == 1)
try:
result = where_func(cond, values, other)
except TypeError:
# we cannot coerce, return a compat dtype
# we are explicitly ignoring errors
block = self.coerce_to_target_dtype(other)
blocks = block.where(
orig_other,
cond,
align=align,
errors=errors,
try_cast=try_cast,
axis=axis,
)
return self._maybe_downcast(blocks, "infer")
if self._can_hold_na or self.ndim == 1:
if transpose:
result = result.T
return [self.make_block(result)]
# might need to separate out blocks
axis = cond.ndim - 1
cond = cond.swapaxes(axis, 0)
mask = np.array([cond[i].all() for i in range(cond.shape[0])], dtype=bool)
result_blocks = []
for m in [mask, ~mask]:
if m.any():
taken = result.take(m.nonzero()[0], axis=axis)
r = maybe_downcast_numeric(taken, self.dtype)
nb = self.make_block(r.T, placement=self.mgr_locs[m])
result_blocks.append(nb)
return result_blocks
def equals(self, other) -> bool:
if self.dtype != other.dtype or self.shape != other.shape:
return False
return array_equivalent(self.values, other.values)
def _unstack(self, unstacker_func, new_columns, n_rows, fill_value):
"""
Return a list of unstacked blocks of self
Parameters
----------
unstacker_func : callable
Partially applied unstacker.
new_columns : Index
All columns of the unstacked BlockManager.
n_rows : int
Only used in ExtensionBlock._unstack
fill_value : int
Only used in ExtensionBlock._unstack
Returns
-------
blocks : list of Block
New blocks of unstacked values.
mask : array_like of bool
The mask of columns of `blocks` we should keep.
"""
unstacker = unstacker_func(self.values.T)
new_items = unstacker.get_new_columns()
new_placement = new_columns.get_indexer(new_items)
new_values, mask = unstacker.get_new_values()
mask = mask.any(0)
new_values = new_values.T[mask]
new_placement = new_placement[mask]
blocks = [make_block(new_values, placement=new_placement)]
return blocks, mask
def quantile(self, qs, interpolation="linear", axis: int = 0):
"""
compute the quantiles of the
Parameters
----------
qs: a scalar or list of the quantiles to be computed
interpolation: type of interpolation, default 'linear'
axis: axis to compute, default 0
Returns
-------
Block
"""
# We should always have ndim == 2 because Series dispatches to DataFrame
assert self.ndim == 2
values = self.get_values()
is_empty = values.shape[axis] == 0
orig_scalar = not is_list_like(qs)
if orig_scalar:
# make list-like, unpack later
qs = [qs]
if is_empty:
# create the array of na_values
# 2d len(values) * len(qs)
result = np.repeat(
np.array([self.fill_value] * len(qs)), len(values)
).reshape(len(values), len(qs))
else:
# asarray needed for Sparse, see GH#24600
mask = np.asarray(isna(values))
result = nanpercentile(
values,
np.array(qs) * 100,
axis=axis,
na_value=self.fill_value,
mask=mask,
ndim=values.ndim,
interpolation=interpolation,
)
result = np.array(result, copy=False)
result = result.T
if orig_scalar and not lib.is_scalar(result):
# result could be scalar in case with is_empty and self.ndim == 1
assert result.shape[-1] == 1, result.shape
result = result[..., 0]
result = lib.item_from_zerodim(result)
ndim = np.ndim(result)
return make_block(result, placement=np.arange(len(result)), ndim=ndim)
def _replace_coerce(
self,
to_replace,
value,
inplace: bool = True,
regex: bool = False,
convert: bool = False,
mask=None,
):
"""
Replace value corresponding to the given boolean array with another
value.
Parameters
----------
to_replace : object or pattern
Scalar to replace or regular expression to match.
value : object
Replacement object.
inplace : bool, default True
Perform inplace modification.
regex : bool, default False
If true, perform regular expression substitution.
convert : bool, default True
If true, try to coerce any object types to better types.
mask : array-like of bool, optional
True indicate corresponding element is ignored.
Returns
-------
A new block if there is anything to replace or the original block.
"""
if mask.any():
if not regex:
self = self.coerce_to_target_dtype(value)
return self.putmask(mask, value, inplace=inplace)
else:
return self._replace_single(
to_replace,
value,
inplace=inplace,
regex=regex,
convert=convert,
mask=mask,
)
return self
class ExtensionBlock(Block):
"""
Block for holding extension types.
Notes
-----
This holds all 3rd-party extension array types. It's also the immediate
parent class for our internal extension types' blocks, CategoricalBlock.
ExtensionArrays are limited to 1-D.
"""
_can_consolidate = False
_verify_integrity = False
_validate_ndim = False
is_extension = True
def __init__(self, values, placement, ndim=None):
"""
Initialize a non-consolidatable block.
'ndim' may be inferred from 'placement'.
This will call continue to call __init__ for the other base
classes mixed in with this Mixin.
"""
values = self._maybe_coerce_values(values)
# Placement must be converted to BlockPlacement so that we can check
# its length
if not isinstance(placement, libinternals.BlockPlacement):
placement = libinternals.BlockPlacement(placement)
# Maybe infer ndim from placement
if ndim is None:
if len(placement) != 1:
ndim = 1
else:
ndim = 2
super().__init__(values, placement, ndim=ndim)
if self.ndim == 2 and len(self.mgr_locs) != 1:
# TODO(2DEA): check unnecessary with 2D EAs
raise AssertionError("block.size != values.size")
@property
def shape(self):
if self.ndim == 1:
return ((len(self.values)),)
return (len(self.mgr_locs), len(self.values))
def iget(self, col):
if self.ndim == 2 and isinstance(col, tuple):
col, loc = col
if not com.is_null_slice(col) and col != 0:
raise IndexError(f"{self} only contains one item")
elif isinstance(col, slice):
if col != slice(None):
raise NotImplementedError(col)
return self.values[[loc]]
return self.values[loc]
else:
if col != 0:
raise IndexError(f"{self} only contains one item")
return self.values
def should_store(self, value: ArrayLike) -> bool:
"""
Can we set the given array-like value inplace?
"""
return isinstance(value, self._holder)
def set(self, locs, values):
assert locs.tolist() == [0]
self.values[:] = values
def putmask(
self, mask, new, align=True, inplace=False, axis=0, transpose=False,
):
"""
putmask the data to the block; we must be a single block and not
generate other blocks
return the resulting block
Parameters
----------
mask : the condition to respect
new : a ndarray/object
align : boolean, perform alignment on other/cond, default is True
inplace : perform inplace modification, default is False
Returns
-------
a new block, the result of the putmask
"""
inplace = validate_bool_kwarg(inplace, "inplace")
# use block's copy logic.
# .values may be an Index which does shallow copy by default
new_values = self.values if inplace else self.copy().values
if isinstance(new, np.ndarray) and len(new) == len(mask):
new = new[mask]
mask = _safe_reshape(mask, new_values.shape)
new_values[mask] = new
return [self.make_block(values=new_values)]
def _get_unstack_items(self, unstacker, new_columns):
"""
Get the placement, values, and mask for a Block unstack.
This is shared between ObjectBlock and ExtensionBlock. They
differ in that ObjectBlock passes the values, while ExtensionBlock
passes the dummy ndarray of positions to be used by a take
later.
Parameters
----------
unstacker : pandas.core.reshape.reshape._Unstacker
new_columns : Index
All columns of the unstacked BlockManager.
Returns
-------
new_placement : ndarray[int]
The placement of the new columns in `new_columns`.
new_values : Union[ndarray, ExtensionArray]
The first return value from _Unstacker.get_new_values.
mask : ndarray[bool]
The second return value from _Unstacker.get_new_values.
"""
# shared with ExtensionBlock
new_items = unstacker.get_new_columns()
new_placement = new_columns.get_indexer(new_items)
new_values, mask = unstacker.get_new_values()
mask = mask.any(0)
return new_placement, new_values, mask
def _maybe_coerce_values(self, values):
"""
Unbox to an extension array.
This will unbox an ExtensionArray stored in an Index or Series.
ExtensionArrays pass through. No dtype coercion is done.
Parameters
----------
values : Index, Series, ExtensionArray
Returns
-------
ExtensionArray
"""
return extract_array(values)
@property
def _holder(self):
# For extension blocks, the holder is values-dependent.
return type(self.values)
@property
def fill_value(self):
# Used in reindex_indexer
return self.values.dtype.na_value
@property
def _can_hold_na(self):
# The default ExtensionArray._can_hold_na is True
return self._holder._can_hold_na
@property
def is_view(self) -> bool:
"""Extension arrays are never treated as views."""
return False
@property
def is_numeric(self):
return self.values.dtype._is_numeric
def setitem(self, indexer, value):
"""
Attempt self.values[indexer] = value, possibly creating a new array.
This differs from Block.setitem by not allowing setitem to change
the dtype of the Block.
Parameters
----------
indexer : tuple, list-like, array-like, slice
The subset of self.values to set
value : object
The value being set
Returns
-------
Block
Notes
-----
`indexer` is a direct slice/positional indexer. `value` must
be a compatible shape.
"""
if isinstance(indexer, tuple):
# we are always 1-D
indexer = indexer[0]
check_setitem_lengths(indexer, value, self.values)
self.values[indexer] = value
return self
def get_values(self, dtype=None):
# ExtensionArrays must be iterable, so this works.
values = np.asarray(self.values)
if values.ndim == self.ndim - 1:
values = values.reshape((1,) + values.shape)
return values
def array_values(self) -> ExtensionArray:
return self.values
def to_native_types(self, slicer=None, na_rep="nan", quoting=None, **kwargs):
"""override to use ExtensionArray astype for the conversion"""
values = self.values
if slicer is not None:
values = values[slicer]
mask = isna(values)
values = np.asarray(values.astype(object))
values[mask] = na_rep
# we are expected to return a 2-d ndarray
return values.reshape(1, len(values))
def take_nd(self, indexer, axis: int = 0, new_mgr_locs=None, fill_tuple=None):
"""
Take values according to indexer and return them as a block.
"""
if fill_tuple is None:
fill_value = None
else:
fill_value = fill_tuple[0]
# axis doesn't matter; we are really a single-dim object
# but are passed the axis depending on the calling routing
# if its REALLY axis 0, then this will be a reindex and not a take
new_values = self.values.take(indexer, fill_value=fill_value, allow_fill=True)
# Called from three places in managers, all of which satisfy
# this assertion
assert not (self.ndim == 1 and new_mgr_locs is None)
if new_mgr_locs is None:
new_mgr_locs = self.mgr_locs
return self.make_block_same_class(new_values, new_mgr_locs)
def _can_hold_element(self, element: Any) -> bool:
# XXX: We may need to think about pushing this onto the array.
# We're doing the same as CategoricalBlock here.
return True
def _slice(self, slicer):
""" return a slice of my values """
# slice the category
# return same dims as we currently have
if isinstance(slicer, tuple) and len(slicer) == 2:
if not com.is_null_slice(slicer[0]):
raise AssertionError("invalid slicing for a 1-ndim categorical")
slicer = slicer[1]
return self.values[slicer]
def concat_same_type(self, to_concat, placement=None):
"""
Concatenate list of single blocks of the same type.
"""
values = self._holder._concat_same_type([blk.values for blk in to_concat])
placement = placement or slice(0, len(values), 1)
return self.make_block_same_class(values, ndim=self.ndim, placement=placement)
def fillna(self, value, limit=None, inplace=False, downcast=None):
values = self.values if inplace else self.values.copy()
values = values.fillna(value=value, limit=limit)
return [
self.make_block_same_class(
values=values, placement=self.mgr_locs, ndim=self.ndim
)
]
def interpolate(
self, method="pad", axis=0, inplace=False, limit=None, fill_value=None, **kwargs
):
values = self.values if inplace else self.values.copy()
return self.make_block_same_class(
values=values.fillna(value=fill_value, method=method, limit=limit),
placement=self.mgr_locs,
)
def diff(self, n: int, axis: int = 1) -> List["Block"]:
if axis == 1:
# we are by definition 1D.
axis = 0
return super().diff(n, axis)
def shift(
self, periods: int, axis: int = 0, fill_value: Any = None,
) -> List["ExtensionBlock"]:
"""
Shift the block by `periods`.
Dispatches to underlying ExtensionArray and re-boxes in an
ExtensionBlock.
"""
return [
self.make_block_same_class(
self.values.shift(periods=periods, fill_value=fill_value),
placement=self.mgr_locs,
ndim=self.ndim,
)
]
def where(
self,
other,
cond,
align=True,
errors="raise",
try_cast: bool = False,
axis: int = 0,
) -> List["Block"]:
if isinstance(other, ABCDataFrame):
# ExtensionArrays are 1-D, so if we get here then
# `other` should be a DataFrame with a single column.
assert other.shape[1] == 1
other = other.iloc[:, 0]
other = extract_array(other, extract_numpy=True)
if isinstance(cond, ABCDataFrame):
assert cond.shape[1] == 1
cond = cond.iloc[:, 0]
cond = extract_array(cond, extract_numpy=True)
if lib.is_scalar(other) and isna(other):
# The default `other` for Series / Frame is np.nan
# we want to replace that with the correct NA value
# for the type
other = self.dtype.na_value
if is_sparse(self.values):
# TODO(SparseArray.__setitem__): remove this if condition
# We need to re-infer the type of the data after doing the
# where, for cases where the subtypes don't match
dtype = None
else:
dtype = self.dtype
result = self.values.copy()
icond = ~cond
if lib.is_scalar(other):
set_other = other
else:
set_other = other[icond]
try:
result[icond] = set_other
except (NotImplementedError, TypeError):
# NotImplementedError for class not implementing `__setitem__`
# TypeError for SparseArray, which implements just to raise
# a TypeError
result = self._holder._from_sequence(
np.where(cond, self.values, other), dtype=dtype
)
return [self.make_block_same_class(result, placement=self.mgr_locs)]
def _unstack(self, unstacker_func, new_columns, n_rows, fill_value):
# ExtensionArray-safe unstack.
# We override ObjectBlock._unstack, which unstacks directly on the
# values of the array. For EA-backed blocks, this would require
# converting to a 2-D ndarray of objects.
# Instead, we unstack an ndarray of integer positions, followed by
# a `take` on the actual values.
dummy_arr = np.arange(n_rows)
dummy_unstacker = functools.partial(unstacker_func, fill_value=-1)
unstacker = dummy_unstacker(dummy_arr)
new_placement, new_values, mask = self._get_unstack_items(
unstacker, new_columns
)
blocks = [
self.make_block_same_class(
self.values.take(indices, allow_fill=True, fill_value=fill_value),
[place],
)
for indices, place in zip(new_values.T, new_placement)
]
return blocks, mask
class ObjectValuesExtensionBlock(ExtensionBlock):
"""
Block providing backwards-compatibility for `.values`.
Used by PeriodArray and IntervalArray to ensure that
Series[T].values is an ndarray of objects.
"""
def external_values(self):
return self.values.astype(object)
class NumericBlock(Block):
__slots__ = ()
is_numeric = True
_can_hold_na = True
class FloatOrComplexBlock(NumericBlock):
__slots__ = ()
def equals(self, other) -> bool:
if self.dtype != other.dtype or self.shape != other.shape:
return False
left, right = self.values, other.values
return ((left == right) | (np.isnan(left) & np.isnan(right))).all()
class FloatBlock(FloatOrComplexBlock):
__slots__ = ()
is_float = True
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return issubclass(tipo.type, (np.floating, np.integer)) and not issubclass(
tipo.type, (np.datetime64, np.timedelta64)
)
return isinstance(
element, (float, int, np.floating, np.int_)
) and not isinstance(
element,
(bool, np.bool_, datetime, timedelta, np.datetime64, np.timedelta64),
)
def to_native_types(
self,
slicer=None,
na_rep="",
float_format=None,
decimal=".",
quoting=None,
**kwargs,
):
""" convert to our native types format, slicing if desired """
values = self.values
if slicer is not None:
values = values[:, slicer]
# see gh-13418: no special formatting is desired at the
# output (important for appropriate 'quoting' behaviour),
# so do not pass it through the FloatArrayFormatter
if float_format is None and decimal == ".":
mask = isna(values)
if not quoting:
values = values.astype(str)
else:
values = np.array(values, dtype="object")
values[mask] = na_rep
return values
from pandas.io.formats.format import FloatArrayFormatter
formatter = FloatArrayFormatter(
values,
na_rep=na_rep,
float_format=float_format,
decimal=decimal,
quoting=quoting,
fixed_width=False,
)
return formatter.get_result_as_array()
def should_store(self, value: ArrayLike) -> bool:
# when inserting a column should not coerce integers to floats
# unnecessarily
return issubclass(value.dtype.type, np.floating) and value.dtype == self.dtype
class ComplexBlock(FloatOrComplexBlock):
__slots__ = ()
is_complex = True
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return issubclass(tipo.type, (np.floating, np.integer, np.complexfloating))
return isinstance(
element, (float, int, complex, np.float_, np.int_)
) and not isinstance(element, (bool, np.bool_))
def should_store(self, value: ArrayLike) -> bool:
return issubclass(value.dtype.type, np.complexfloating)
class IntBlock(NumericBlock):
__slots__ = ()
is_integer = True
_can_hold_na = False
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return (
issubclass(tipo.type, np.integer)
and not issubclass(tipo.type, (np.datetime64, np.timedelta64))
and self.dtype.itemsize >= tipo.itemsize
)
return is_integer(element)
def should_store(self, value: ArrayLike) -> bool:
return is_integer_dtype(value) and value.dtype == self.dtype
class DatetimeLikeBlockMixin:
"""Mixin class for DatetimeBlock, DatetimeTZBlock, and TimedeltaBlock."""
@property
def _holder(self):
return DatetimeArray
def should_store(self, value):
return is_dtype_equal(self.dtype, value.dtype)
@property
def fill_value(self):
return np.datetime64("NaT", "ns")
def get_values(self, dtype=None):
"""
return object dtype as boxed values, such as Timestamps/Timedelta
"""
if is_object_dtype(dtype):
values = self.values.ravel()
result = self._holder(values).astype(object)
return result.reshape(self.values.shape)
return self.values
def internal_values(self):
# Override to return DatetimeArray and TimedeltaArray
return self.array_values()
def iget(self, key):
# GH#31649 we need to wrap scalars in Timestamp/Timedelta
# TODO(EA2D): this can be removed if we ever have 2D EA
result = super().iget(key)
if isinstance(result, np.datetime64):
result = Timestamp(result)
elif isinstance(result, np.timedelta64):
result = Timedelta(result)
return result
def shift(self, periods, axis=0, fill_value=None):
# TODO(EA2D) this is unnecessary if these blocks are backed by 2D EAs
values = self.array_values()
new_values = values.shift(periods, fill_value=fill_value, axis=axis)
return self.make_block_same_class(new_values)
class DatetimeBlock(DatetimeLikeBlockMixin, Block):
__slots__ = ()
is_datetime = True
def __init__(self, values, placement, ndim=None):
values = self._maybe_coerce_values(values)
super().__init__(values, placement=placement, ndim=ndim)
@property
def _can_hold_na(self):
return True
def _maybe_coerce_values(self, values):
"""
Input validation for values passed to __init__. Ensure that
we have datetime64ns, coercing if necessary.
Parameters
----------
values : array-like
Must be convertible to datetime64
Returns
-------
values : ndarray[datetime64ns]
Overridden by DatetimeTZBlock.
"""
if values.dtype != _NS_DTYPE:
values = conversion.ensure_datetime64ns(values)
if isinstance(values, DatetimeArray):
values = values._data
assert isinstance(values, np.ndarray), type(values)
return values
def astype(self, dtype, copy: bool = False, errors: str = "raise"):
"""
these automatically copy, so copy=True has no effect
raise on an except if raise == True
"""
dtype = pandas_dtype(dtype)
# if we are passed a datetime64[ns, tz]
if is_datetime64tz_dtype(dtype):
values = self.values
if copy:
# this should be the only copy
values = values.copy()
if getattr(values, "tz", None) is None:
values = DatetimeArray(values).tz_localize("UTC")
values = values.tz_convert(dtype.tz)
return self.make_block(values)
# delegate
return super().astype(dtype=dtype, copy=copy, errors=errors)
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
if self.is_datetimetz:
# require exact match, since non-nano does not exist
return is_dtype_equal(tipo, self.dtype) or is_valid_nat_for_dtype(
element, self.dtype
)
# GH#27419 if we get a non-nano datetime64 object
return is_datetime64_dtype(tipo)
elif element is NaT:
return True
elif isinstance(element, datetime):
if self.is_datetimetz:
return tz_compare(element.tzinfo, self.dtype.tz)
return element.tzinfo is None
return is_valid_nat_for_dtype(element, self.dtype)
def to_native_types(
self, slicer=None, na_rep=None, date_format=None, quoting=None, **kwargs
):
""" convert to our native types format, slicing if desired """
values = self.values
i8values = self.values.view("i8")
if slicer is not None:
values = values[..., slicer]
i8values = i8values[..., slicer]
from pandas.io.formats.format import _get_format_datetime64_from_values
fmt = _get_format_datetime64_from_values(values, date_format)
result = tslib.format_array_from_datetime(
i8values.ravel(),
tz=getattr(self.values, "tz", None),
format=fmt,
na_rep=na_rep,
).reshape(i8values.shape)
return np.atleast_2d(result)
def set(self, locs, values):
"""
See Block.set.__doc__
"""
values = conversion.ensure_datetime64ns(values, copy=False)
self.values[locs] = values
def external_values(self):
return np.asarray(self.values.astype("datetime64[ns]", copy=False))
def array_values(self) -> ExtensionArray:
return DatetimeArray._simple_new(self.values)
class DatetimeTZBlock(ExtensionBlock, DatetimeBlock):
""" implement a datetime64 block with a tz attribute """
__slots__ = ()
is_datetimetz = True
is_extension = True
internal_values = Block.internal_values
_can_hold_element = DatetimeBlock._can_hold_element
to_native_types = DatetimeBlock.to_native_types
fill_value = np.datetime64("NaT", "ns")
should_store = DatetimeBlock.should_store
@property
def _holder(self):
return DatetimeArray
def _maybe_coerce_values(self, values):
"""
Input validation for values passed to __init__. Ensure that
we have datetime64TZ, coercing if necessary.
Parameters
----------
values : array-like
Must be convertible to datetime64
Returns
-------
values : DatetimeArray
"""
if not isinstance(values, self._holder):
values = self._holder(values)
if values.tz is None:
raise ValueError("cannot create a DatetimeTZBlock without a tz")
return values
@property
def is_view(self) -> bool:
""" return a boolean if I am possibly a view """
# check the ndarray values of the DatetimeIndex values
return self.values._data.base is not None
def get_values(self, dtype=None):
"""
Returns an ndarray of values.
Parameters
----------
dtype : np.dtype
Only `object`-like dtypes are respected here (not sure
why).
Returns
-------
values : ndarray
When ``dtype=object``, then and object-dtype ndarray of
boxed values is returned. Otherwise, an M8[ns] ndarray
is returned.
DatetimeArray is always 1-d. ``get_values`` will reshape
the return value to be the same dimensionality as the
block.
"""
values = self.values
if is_object_dtype(dtype):
values = values.astype(object)
values = np.asarray(values)
if self.ndim == 2:
# Ensure that our shape is correct for DataFrame.
# ExtensionArrays are always 1-D, even in a DataFrame when
# the analogous NumPy-backed column would be a 2-D ndarray.
values = values.reshape(1, -1)
return values
def _slice(self, slicer):
""" return a slice of my values """
if isinstance(slicer, tuple):
col, loc = slicer
if not com.is_null_slice(col) and col != 0:
raise IndexError(f"{self} only contains one item")
return self.values[loc]
return self.values[slicer]
def diff(self, n: int, axis: int = 0) -> List["Block"]:
"""
1st discrete difference.
Parameters
----------
n : int
Number of periods to diff.
axis : int, default 0
Axis to diff upon.
Returns
-------
A list with a new TimeDeltaBlock.
Notes
-----
The arguments here are mimicking shift so they are called correctly
by apply.
"""
if axis == 0:
# Cannot currently calculate diff across multiple blocks since this
# function is invoked via apply
raise NotImplementedError
new_values = (self.values - self.shift(n, axis=axis)[0].values).asi8
# Reshape the new_values like how algos.diff does for timedelta data
new_values = new_values.reshape(1, len(new_values))
new_values = new_values.astype("timedelta64[ns]")
return [TimeDeltaBlock(new_values, placement=self.mgr_locs.indexer)]
def concat_same_type(self, to_concat, placement=None):
# need to handle concat([tz1, tz2]) here, since DatetimeArray
# only handles cases where all the tzs are the same.
# Instead of placing the condition here, it could also go into the
# is_uniform_join_units check, but I'm not sure what is better.
if len({x.dtype for x in to_concat}) > 1:
values = concat_datetime([x.values for x in to_concat])
placement = placement or slice(0, len(values), 1)
if self.ndim > 1:
values = np.atleast_2d(values)
return ObjectBlock(values, ndim=self.ndim, placement=placement)
return super().concat_same_type(to_concat, placement)
def fillna(self, value, limit=None, inplace=False, downcast=None):
# We support filling a DatetimeTZ with a `value` whose timezone
# is different by coercing to object.
if self._can_hold_element(value):
return super().fillna(value, limit, inplace, downcast)
# different timezones, or a non-tz
return self.astype(object).fillna(
value, limit=limit, inplace=inplace, downcast=downcast
)
def setitem(self, indexer, value):
# https://github.com/pandas-dev/pandas/issues/24020
# Need a dedicated setitem until #24020 (type promotion in setitem
# for extension arrays) is designed and implemented.
if self._can_hold_element(value) or (
isinstance(indexer, np.ndarray) and indexer.size == 0
):
return super().setitem(indexer, value)
obj_vals = self.values.astype(object)
newb = make_block(
obj_vals, placement=self.mgr_locs, klass=ObjectBlock, ndim=self.ndim
)
return newb.setitem(indexer, value)
def equals(self, other) -> bool:
# override for significant performance improvement
if self.dtype != other.dtype or self.shape != other.shape:
return False
return (self.values.view("i8") == other.values.view("i8")).all()
def quantile(self, qs, interpolation="linear", axis=0):
naive = self.values.view("M8[ns]")
# kludge for 2D block with 1D values
naive = naive.reshape(self.shape)
blk = self.make_block(naive)
res_blk = blk.quantile(qs, interpolation=interpolation, axis=axis)
# ravel is kludge for 2D block with 1D values, assumes column-like
aware = self._holder(res_blk.values.ravel(), dtype=self.dtype)
return self.make_block_same_class(aware, ndim=res_blk.ndim)
class TimeDeltaBlock(DatetimeLikeBlockMixin, IntBlock):
__slots__ = ()
is_timedelta = True
_can_hold_na = True
is_numeric = False
fill_value = np.timedelta64("NaT", "ns")
def __init__(self, values, placement, ndim=None):
if values.dtype != _TD_DTYPE:
values = conversion.ensure_timedelta64ns(values)
if isinstance(values, TimedeltaArray):
values = values._data
assert isinstance(values, np.ndarray), type(values)
super().__init__(values, placement=placement, ndim=ndim)
@property
def _holder(self):
return TimedeltaArray
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return issubclass(tipo.type, np.timedelta64)
elif element is NaT:
return True
elif isinstance(element, (timedelta, np.timedelta64)):
return True
return is_valid_nat_for_dtype(element, self.dtype)
def fillna(self, value, **kwargs):
# allow filling with integers to be
# interpreted as nanoseconds
if is_integer(value):
# Deprecation GH#24694, GH#19233
raise TypeError(
"Passing integers to fillna for timedelta64[ns] dtype is no "
"longer supported. To obtain the old behavior, pass "
"`pd.Timedelta(seconds=n)` instead."
)
return super().fillna(value, **kwargs)
def to_native_types(self, slicer=None, na_rep=None, quoting=None, **kwargs):
""" convert to our native types format, slicing if desired """
values = self.values
if slicer is not None:
values = values[:, slicer]
mask = isna(values)
rvalues = np.empty(values.shape, dtype=object)
if na_rep is None:
na_rep = "NaT"
rvalues[mask] = na_rep
imask = (~mask).ravel()
# FIXME:
# should use the formats.format.Timedelta64Formatter here
# to figure what format to pass to the Timedelta
# e.g. to not show the decimals say
rvalues.flat[imask] = np.array(
[Timedelta(val)._repr_base(format="all") for val in values.ravel()[imask]],
dtype=object,
)
return rvalues
def external_values(self):
return np.asarray(self.values.astype("timedelta64[ns]", copy=False))
def array_values(self) -> ExtensionArray:
return TimedeltaArray._simple_new(self.values)
class BoolBlock(NumericBlock):
__slots__ = ()
is_bool = True
_can_hold_na = False
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return issubclass(tipo.type, np.bool_)
return isinstance(element, (bool, np.bool_))
def should_store(self, value: ArrayLike) -> bool:
return issubclass(value.dtype.type, np.bool_) and not is_extension_array_dtype(
value
)
def replace(
self, to_replace, value, inplace=False, filter=None, regex=False, convert=True
):
inplace = validate_bool_kwarg(inplace, "inplace")
to_replace_values = np.atleast_1d(to_replace)
if not np.can_cast(to_replace_values, bool):
return self
return super().replace(
to_replace,
value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
class ObjectBlock(Block):
__slots__ = ()
is_object = True
_can_hold_na = True
def __init__(self, values, placement=None, ndim=2):
if issubclass(values.dtype.type, str):
values = np.array(values, dtype=object)
super().__init__(values, ndim=ndim, placement=placement)
@property
def is_bool(self):
"""
we can be a bool if we have only bool values but are of type
object
"""
return lib.is_bool_array(self.values.ravel())
def convert(
self,
copy: bool = True,
datetime: bool = True,
numeric: bool = True,
timedelta: bool = True,
coerce: bool = False,
):
"""
attempt to coerce any object types to better types return a copy of
the block (if copy = True) by definition we ARE an ObjectBlock!!!!!
can return multiple blocks!
"""
# operate column-by-column
def f(mask, val, idx):
shape = val.shape
values = soft_convert_objects(
val.ravel(),
datetime=datetime,
numeric=numeric,
timedelta=timedelta,
coerce=coerce,
copy=copy,
)
if isinstance(values, np.ndarray):
# TODO: allow EA once reshape is supported
values = values.reshape(shape)
values = _block_shape(values, ndim=self.ndim)
return values
if self.ndim == 2:
blocks = self.split_and_operate(None, f, False)
else:
values = f(None, self.values.ravel(), None)
blocks = [make_block(values, ndim=self.ndim, placement=self.mgr_locs)]
return blocks
def _maybe_downcast(self, blocks: List["Block"], downcast=None) -> List["Block"]:
if downcast is not None:
return blocks
# split and convert the blocks
return _extend_blocks([b.convert(datetime=True, numeric=False) for b in blocks])
def _can_hold_element(self, element: Any) -> bool:
return True
def should_store(self, value: ArrayLike) -> bool:
return not (
issubclass(
value.dtype.type,
(np.integer, np.floating, np.complexfloating, np.datetime64, np.bool_),
)
or is_extension_array_dtype(value)
)
def replace(
self, to_replace, value, inplace=False, filter=None, regex=False, convert=True
):
to_rep_is_list = is_list_like(to_replace)
value_is_list = is_list_like(value)
both_lists = to_rep_is_list and value_is_list
either_list = to_rep_is_list or value_is_list
result_blocks = []
blocks = [self]
if not either_list and is_re(to_replace):
return self._replace_single(
to_replace,
value,
inplace=inplace,
filter=filter,
regex=True,
convert=convert,
)
elif not (either_list or regex):
return super().replace(
to_replace,
value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
elif both_lists:
for to_rep, v in zip(to_replace, value):
result_blocks = []
for b in blocks:
result = b._replace_single(
to_rep,
v,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
result_blocks = _extend_blocks(result, result_blocks)
blocks = result_blocks
return result_blocks
elif to_rep_is_list and regex:
for to_rep in to_replace:
result_blocks = []
for b in blocks:
result = b._replace_single(
to_rep,
value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
result_blocks = _extend_blocks(result, result_blocks)
blocks = result_blocks
return result_blocks
return self._replace_single(
to_replace,
value,
inplace=inplace,
filter=filter,
convert=convert,
regex=regex,
)
def _replace_single(
self,
to_replace,
value,
inplace=False,
filter=None,
regex=False,
convert=True,
mask=None,
):
"""
Replace elements by the given value.
Parameters
----------
to_replace : object or pattern
Scalar to replace or regular expression to match.
value : object
Replacement object.
inplace : bool, default False
Perform inplace modification.
filter : list, optional
regex : bool, default False
If true, perform regular expression substitution.
convert : bool, default True
If true, try to coerce any object types to better types.
mask : array-like of bool, optional
True indicate corresponding element is ignored.
Returns
-------
a new block, the result after replacing
"""
inplace = validate_bool_kwarg(inplace, "inplace")
# to_replace is regex compilable
to_rep_re = regex and is_re_compilable(to_replace)
# regex is regex compilable
regex_re = is_re_compilable(regex)
# only one will survive
if to_rep_re and regex_re:
raise AssertionError(
"only one of to_replace and regex can be regex compilable"
)
# if regex was passed as something that can be a regex (rather than a
# boolean)
if regex_re:
to_replace = regex
regex = regex_re or to_rep_re
# try to get the pattern attribute (compiled re) or it's a string
if is_re(to_replace):
pattern = to_replace.pattern
else:
pattern = to_replace
# if the pattern is not empty and to_replace is either a string or a
# regex
if regex and pattern:
rx = re.compile(to_replace)
else:
# if the thing to replace is not a string or compiled regex call
# the superclass method -> to_replace is some kind of object
return super().replace(
to_replace, value, inplace=inplace, filter=filter, regex=regex
)
new_values = self.values if inplace else self.values.copy()
# deal with replacing values with objects (strings) that match but
# whose replacement is not a string (numeric, nan, object)
if isna(value) or not isinstance(value, str):
def re_replacer(s):
if is_re(rx) and isinstance(s, str):
return value if rx.search(s) is not None else s
else:
return s
else:
# value is guaranteed to be a string here, s can be either a string
# or null if it's null it gets returned
def re_replacer(s):
if is_re(rx) and isinstance(s, str):
return rx.sub(value, s)
else:
return s
f = np.vectorize(re_replacer, otypes=[self.dtype])
if filter is None:
filt = slice(None)
else:
filt = self.mgr_locs.isin(filter).nonzero()[0]
if mask is None:
new_values[filt] = f(new_values[filt])
else:
new_values[filt][mask] = f(new_values[filt][mask])
# convert
block = self.make_block(new_values)
if convert:
block = block.convert(numeric=False)
return block
def _replace_coerce(
self, to_replace, value, inplace=True, regex=False, convert=False, mask=None
):
"""
Replace value corresponding to the given boolean array with another
value.
Parameters
----------
to_replace : object or pattern
Scalar to replace or regular expression to match.
value : object
Replacement object.
inplace : bool, default False
Perform inplace modification.
regex : bool, default False
If true, perform regular expression substitution.
convert : bool, default True
If true, try to coerce any object types to better types.
mask : array-like of bool, optional
True indicate corresponding element is ignored.
Returns
-------
A new block if there is anything to replace or the original block.
"""
if mask.any():
block = super()._replace_coerce(
to_replace=to_replace,
value=value,
inplace=inplace,
regex=regex,
convert=convert,
mask=mask,
)
if convert:
block = [b.convert(numeric=False, copy=True) for b in block]
return block
if convert:
return [self.convert(numeric=False, copy=True)]
return self
class CategoricalBlock(ExtensionBlock):
__slots__ = ()
is_categorical = True
_verify_integrity = True
_can_hold_na = True
_concatenator = staticmethod(concat_categorical)
def __init__(self, values, placement, ndim=None):
# coerce to categorical if we can
values = extract_array(values)
assert isinstance(values, Categorical), type(values)
super().__init__(values, placement=placement, ndim=ndim)
@property
def _holder(self):
return Categorical
def should_store(self, arr: ArrayLike):
return isinstance(arr, self._holder) and is_dtype_equal(self.dtype, arr.dtype)
def to_native_types(self, slicer=None, na_rep="", quoting=None, **kwargs):
""" convert to our native types format, slicing if desired """
values = self.values
if slicer is not None:
# Categorical is always one dimension
values = values[slicer]
mask = isna(values)
values = np.array(values, dtype="object")
values[mask] = na_rep
# we are expected to return a 2-d ndarray
return values.reshape(1, len(values))
def concat_same_type(self, to_concat, placement=None):
"""
Concatenate list of single blocks of the same type.
Note that this CategoricalBlock._concat_same_type *may* not
return a CategoricalBlock. When the categories in `to_concat`
differ, this will return an object ndarray.
If / when we decide we don't like that behavior:
1. Change Categorical._concat_same_type to use union_categoricals
2. Delete this method.
"""
values = self._concatenator(
[blk.values for blk in to_concat], axis=self.ndim - 1
)
# not using self.make_block_same_class as values can be object dtype
return make_block(
values, placement=placement or slice(0, len(values), 1), ndim=self.ndim
)
def replace(
self,
to_replace,
value,
inplace: bool = False,
filter=None,
regex: bool = False,
convert: bool = True,
):
inplace = validate_bool_kwarg(inplace, "inplace")
result = self if inplace else self.copy()
if filter is None: # replace was called on a series
result.values.replace(to_replace, value, inplace=True)
if convert:
return result.convert(numeric=False, copy=not inplace)
else:
return result
else: # replace was called on a DataFrame
if not isna(value):
result.values.add_categories(value, inplace=True)
return super(CategoricalBlock, result).replace(
to_replace, value, inplace, filter, regex, convert
)
# -----------------------------------------------------------------
# Constructor Helpers
def get_block_type(values, dtype=None):
"""
Find the appropriate Block subclass to use for the given values and dtype.
Parameters
----------
values : ndarray-like
dtype : numpy or pandas dtype
Returns
-------
cls : class, subclass of Block
"""
dtype = dtype or values.dtype
vtype = dtype.type
if is_sparse(dtype):
# Need this first(ish) so that Sparse[datetime] is sparse
cls = ExtensionBlock
elif is_categorical(values):
cls = CategoricalBlock
elif issubclass(vtype, np.datetime64):
assert not is_datetime64tz_dtype(values)
cls = DatetimeBlock
elif is_datetime64tz_dtype(values):
cls = DatetimeTZBlock
elif is_interval_dtype(dtype) or is_period_dtype(dtype):
cls = ObjectValuesExtensionBlock
elif is_extension_array_dtype(values):
cls = ExtensionBlock
elif issubclass(vtype, np.floating):
cls = FloatBlock
elif issubclass(vtype, np.timedelta64):
assert issubclass(vtype, np.integer)
cls = TimeDeltaBlock
elif issubclass(vtype, np.complexfloating):
cls = ComplexBlock
elif issubclass(vtype, np.integer):
cls = IntBlock
elif dtype == np.bool_:
cls = BoolBlock
else:
cls = ObjectBlock
return cls
def make_block(values, placement, klass=None, ndim=None, dtype=None):
# Ensure that we don't allow PandasArray / PandasDtype in internals.
# For now, blocks should be backed by ndarrays when possible.
if isinstance(values, ABCPandasArray):
values = values.to_numpy()
if ndim and ndim > 1:
values = np.atleast_2d(values)
if isinstance(dtype, PandasDtype):
dtype = dtype.numpy_dtype
if klass is None:
dtype = dtype or values.dtype
klass = get_block_type(values, dtype)
elif klass is DatetimeTZBlock and not is_datetime64tz_dtype(values):
# TODO: This is no longer hit internally; does it need to be retained
# for e.g. pyarrow?
values = DatetimeArray._simple_new(values, dtype=dtype)
return klass(values, ndim=ndim, placement=placement)
# -----------------------------------------------------------------
def _extend_blocks(result, blocks=None):
""" return a new extended blocks, given the result """
if blocks is None:
blocks = []
if isinstance(result, list):
for r in result:
if isinstance(r, list):
blocks.extend(r)
else:
blocks.append(r)
else:
assert isinstance(result, Block), type(result)
blocks.append(result)
return blocks
def _block_shape(values, ndim=1, shape=None):
""" guarantee the shape of the values to be at least 1 d """
if values.ndim < ndim:
if shape is None:
shape = values.shape
if not is_extension_array_dtype(values):
# TODO: https://github.com/pandas-dev/pandas/issues/23023
# block.shape is incorrect for "2D" ExtensionArrays
# We can't, and don't need to, reshape.
values = values.reshape(tuple((1,) + shape))
return values
def _merge_blocks(blocks, dtype=None, _can_consolidate=True):
if len(blocks) == 1:
return blocks[0]
if _can_consolidate:
if dtype is None:
if len({b.dtype for b in blocks}) != 1:
raise AssertionError("_merge_blocks are invalid!")
# FIXME: optimization potential in case all mgrs contain slices and
# combination of those slices is a slice, too.
new_mgr_locs = np.concatenate([b.mgr_locs.as_array for b in blocks])
new_values = np.vstack([b.values for b in blocks])
argsort = np.argsort(new_mgr_locs)
new_values = new_values[argsort]
new_mgr_locs = new_mgr_locs[argsort]
return make_block(new_values, placement=new_mgr_locs)
# no merge
return blocks
def _safe_reshape(arr, new_shape):
"""
If possible, reshape `arr` to have shape `new_shape`,
with a couple of exceptions (see gh-13012):
1) If `arr` is a ExtensionArray or Index, `arr` will be
returned as is.
2) If `arr` is a Series, the `_values` attribute will
be reshaped and returned.
Parameters
----------
arr : array-like, object to be reshaped
new_shape : int or tuple of ints, the new shape
"""
if isinstance(arr, ABCSeries):
arr = arr._values
if not isinstance(arr, ABCExtensionArray):
arr = arr.reshape(new_shape)
return arr
def _putmask_smart(v: np.ndarray, mask: np.ndarray, n) -> np.ndarray:
"""
Return a new ndarray, try to preserve dtype if possible.
Parameters
----------
v : np.ndarray
`values`, updated in-place.
mask : np.ndarray[bool]
Applies to both sides (array like).
n : `new values` either scalar or an array like aligned with `values`
Returns
-------
values : ndarray with updated values
this *may* be a copy of the original
See Also
--------
ndarray.putmask
"""
# we cannot use np.asarray() here as we cannot have conversions
# that numpy does when numeric are mixed with strings
# n should be the length of the mask or a scalar here
if not is_list_like(n):
n = np.repeat(n, len(mask))
# see if we are only masking values that if putted
# will work in the current dtype
try:
nn = n[mask]
except TypeError:
# TypeError: only integer scalar arrays can be converted to a scalar index
pass
else:
# make sure that we have a nullable type
# if we have nulls
if not _isna_compat(v, nn[0]):
pass
elif not (is_float_dtype(nn.dtype) or is_integer_dtype(nn.dtype)):
# only compare integers/floats
pass
elif not (is_float_dtype(v.dtype) or is_integer_dtype(v.dtype)):
# only compare integers/floats
pass
else:
# we ignore ComplexWarning here
with warnings.catch_warnings(record=True):
warnings.simplefilter("ignore", np.ComplexWarning)
nn_at = nn.astype(v.dtype)
comp = nn == nn_at
if is_list_like(comp) and comp.all():
nv = v.copy()
nv[mask] = nn_at
return nv
n = np.asarray(n)
def _putmask_preserve(nv, n):
try:
nv[mask] = n[mask]
except (IndexError, ValueError):
nv[mask] = n
return nv
# preserves dtype if possible
if v.dtype.kind == n.dtype.kind:
return _putmask_preserve(v, n)
# change the dtype if needed
dtype, _ = maybe_promote(n.dtype)
v = v.astype(dtype)
return _putmask_preserve(v, n)
| BugsInPy/BugsInPy/temp/projects/pandas/bug-41-fixed/pandas/pandas/core/internals/blocks.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-41-buggy/pandas/pandas/core/internals/blocks.py |
pandas-bug-98 | from datetime import datetime
import operator
from textwrap import dedent
from typing import Dict, FrozenSet, Hashable, Optional, Union
import warnings
import numpy as np
from pandas._libs import algos as libalgos, index as libindex, lib
import pandas._libs.join as libjoin
from pandas._libs.lib import is_datetime_array
from pandas._libs.tslibs import OutOfBoundsDatetime, Timestamp
from pandas._libs.tslibs.period import IncompatibleFrequency
from pandas._libs.tslibs.timezones import tz_compare
from pandas.compat import set_function_name
from pandas.compat.numpy import function as nv
from pandas.util._decorators import Appender, Substitution, cache_readonly
from pandas.core.dtypes import concat as _concat
from pandas.core.dtypes.cast import maybe_cast_to_integer_array
from pandas.core.dtypes.common import (
ensure_categorical,
ensure_int64,
ensure_object,
ensure_platform_int,
is_bool,
is_bool_dtype,
is_categorical,
is_categorical_dtype,
is_datetime64_any_dtype,
is_datetime64tz_dtype,
is_dtype_equal,
is_extension_array_dtype,
is_float,
is_float_dtype,
is_hashable,
is_integer,
is_integer_dtype,
is_interval_dtype,
is_iterator,
is_list_like,
is_object_dtype,
is_period_dtype,
is_scalar,
is_signed_integer_dtype,
is_timedelta64_dtype,
is_unsigned_integer_dtype,
)
from pandas.core.dtypes.concat import concat_compat
from pandas.core.dtypes.generic import (
ABCCategorical,
ABCDataFrame,
ABCDatetimeArray,
ABCDatetimeIndex,
ABCIndexClass,
ABCIntervalIndex,
ABCMultiIndex,
ABCPandasArray,
ABCPeriodIndex,
ABCSeries,
ABCTimedeltaIndex,
)
from pandas.core.dtypes.missing import array_equivalent, isna
from pandas.core import ops
from pandas.core.accessor import CachedAccessor
import pandas.core.algorithms as algos
from pandas.core.arrays import ExtensionArray
from pandas.core.base import IndexOpsMixin, PandasObject
import pandas.core.common as com
from pandas.core.construction import extract_array
from pandas.core.indexers import maybe_convert_indices
from pandas.core.indexes.frozen import FrozenList
import pandas.core.missing as missing
from pandas.core.ops import get_op_result_name
from pandas.core.ops.invalid import make_invalid_op
from pandas.core.strings import StringMethods
from pandas.io.formats.printing import (
default_pprint,
format_object_attrs,
format_object_summary,
pprint_thing,
)
__all__ = ["Index"]
_unsortable_types = frozenset(("mixed", "mixed-integer"))
_index_doc_kwargs = dict(
klass="Index",
inplace="",
target_klass="Index",
raises_section="",
unique="Index",
duplicated="np.ndarray",
)
_index_shared_docs = dict()
def _make_comparison_op(op, cls):
def cmp_method(self, other):
if isinstance(other, (np.ndarray, Index, ABCSeries, ExtensionArray)):
if other.ndim > 0 and len(self) != len(other):
raise ValueError("Lengths must match to compare")
if is_object_dtype(self) and isinstance(other, ABCCategorical):
left = type(other)(self._values, dtype=other.dtype)
return op(left, other)
elif is_object_dtype(self) and not isinstance(self, ABCMultiIndex):
# don't pass MultiIndex
with np.errstate(all="ignore"):
result = ops.comp_method_OBJECT_ARRAY(op, self.values, other)
else:
with np.errstate(all="ignore"):
result = op(self.values, np.asarray(other))
if is_bool_dtype(result):
return result
return ops.invalid_comparison(self, other, op)
name = f"__{op.__name__}__"
return set_function_name(cmp_method, name, cls)
def _make_arithmetic_op(op, cls):
def index_arithmetic_method(self, other):
if isinstance(other, (ABCSeries, ABCDataFrame, ABCTimedeltaIndex)):
return NotImplemented
from pandas import Series
result = op(Series(self), other)
if isinstance(result, tuple):
return (Index(result[0]), Index(result[1]))
return Index(result)
name = f"__{op.__name__}__"
# TODO: docstring?
return set_function_name(index_arithmetic_method, name, cls)
class InvalidIndexError(Exception):
pass
_o_dtype = np.dtype(object)
_Identity = object
def _new_Index(cls, d):
"""
This is called upon unpickling, rather than the default which doesn't
have arguments and breaks __new__.
"""
# required for backward compat, because PI can't be instantiated with
# ordinals through __new__ GH #13277
if issubclass(cls, ABCPeriodIndex):
from pandas.core.indexes.period import _new_PeriodIndex
return _new_PeriodIndex(cls, **d)
if issubclass(cls, ABCMultiIndex):
if "labels" in d and "codes" not in d:
# GH#23752 "labels" kwarg has been replaced with "codes"
d["codes"] = d.pop("labels")
return cls.__new__(cls, **d)
class Index(IndexOpsMixin, PandasObject):
"""
Immutable ndarray implementing an ordered, sliceable set. The basic object
storing axis labels for all pandas objects.
Parameters
----------
data : array-like (1-dimensional)
dtype : NumPy dtype (default: object)
If dtype is None, we find the dtype that best fits the data.
If an actual dtype is provided, we coerce to that dtype if it's safe.
Otherwise, an error will be raised.
copy : bool
Make a copy of input ndarray.
name : object
Name to be stored in the index.
tupleize_cols : bool (default: True)
When True, attempt to create a MultiIndex if possible.
See Also
--------
RangeIndex : Index implementing a monotonic integer range.
CategoricalIndex : Index of :class:`Categorical` s.
MultiIndex : A multi-level, or hierarchical, Index.
IntervalIndex : An Index of :class:`Interval` s.
DatetimeIndex, TimedeltaIndex, PeriodIndex
Int64Index, UInt64Index, Float64Index
Notes
-----
An Index instance can **only** contain hashable objects
Examples
--------
>>> pd.Index([1, 2, 3])
Int64Index([1, 2, 3], dtype='int64')
>>> pd.Index(list('abc'))
Index(['a', 'b', 'c'], dtype='object')
"""
# tolist is not actually deprecated, just suppressed in the __dir__
_deprecations: FrozenSet[str] = (
PandasObject._deprecations
| IndexOpsMixin._deprecations
| frozenset(["contains", "set_value"])
)
# To hand over control to subclasses
_join_precedence = 1
# Cython methods; see github.com/cython/cython/issues/2647
# for why we need to wrap these instead of making them class attributes
# Moreover, cython will choose the appropriate-dtyped sub-function
# given the dtypes of the passed arguments
def _left_indexer_unique(self, left, right):
return libjoin.left_join_indexer_unique(left, right)
def _left_indexer(self, left, right):
return libjoin.left_join_indexer(left, right)
def _inner_indexer(self, left, right):
return libjoin.inner_join_indexer(left, right)
def _outer_indexer(self, left, right):
return libjoin.outer_join_indexer(left, right)
_typ = "index"
_data: Union[ExtensionArray, np.ndarray]
_id = None
_name: Optional[Hashable] = None
# MultiIndex.levels previously allowed setting the index name. We
# don't allow this anymore, and raise if it happens rather than
# failing silently.
_no_setting_name: bool = False
_comparables = ["name"]
_attributes = ["name"]
_is_numeric_dtype = False
_can_hold_na = True
# would we like our indexing holder to defer to us
_defer_to_indexing = False
# prioritize current class for _shallow_copy_with_infer,
# used to infer integers as datetime-likes
_infer_as_myclass = False
_engine_type = libindex.ObjectEngine
# whether we support partial string indexing. Overridden
# in DatetimeIndex and PeriodIndex
_supports_partial_string_indexing = False
_accessors = {"str"}
str = CachedAccessor("str", StringMethods)
# --------------------------------------------------------------------
# Constructors
def __new__(
cls, data=None, dtype=None, copy=False, name=None, tupleize_cols=True, **kwargs,
) -> "Index":
from .range import RangeIndex
from pandas import PeriodIndex, DatetimeIndex, TimedeltaIndex
from .numeric import Float64Index, Int64Index, UInt64Index
from .interval import IntervalIndex
from .category import CategoricalIndex
name = maybe_extract_name(name, data, cls)
if isinstance(data, ABCPandasArray):
# ensure users don't accidentally put a PandasArray in an index.
data = data.to_numpy()
# range
if isinstance(data, RangeIndex):
return RangeIndex(start=data, copy=copy, dtype=dtype, name=name)
elif isinstance(data, range):
return RangeIndex.from_range(data, dtype=dtype, name=name)
# categorical
elif is_categorical_dtype(data) or is_categorical_dtype(dtype):
return CategoricalIndex(data, dtype=dtype, copy=copy, name=name, **kwargs)
# interval
elif (
is_interval_dtype(data) or is_interval_dtype(dtype)
) and not is_object_dtype(dtype):
closed = kwargs.get("closed", None)
return IntervalIndex(data, dtype=dtype, name=name, copy=copy, closed=closed)
elif (
is_datetime64_any_dtype(data)
or is_datetime64_any_dtype(dtype)
or "tz" in kwargs
):
if is_dtype_equal(_o_dtype, dtype):
# GH#23524 passing `dtype=object` to DatetimeIndex is invalid,
# will raise in the where `data` is already tz-aware. So
# we leave it out of this step and cast to object-dtype after
# the DatetimeIndex construction.
# Note we can pass copy=False because the .astype below
# will always make a copy
return DatetimeIndex(data, copy=False, name=name, **kwargs).astype(
object
)
else:
return DatetimeIndex(data, copy=copy, name=name, dtype=dtype, **kwargs)
elif is_timedelta64_dtype(data) or is_timedelta64_dtype(dtype):
if is_dtype_equal(_o_dtype, dtype):
# Note we can pass copy=False because the .astype below
# will always make a copy
return TimedeltaIndex(data, copy=False, name=name, **kwargs).astype(
object
)
else:
return TimedeltaIndex(data, copy=copy, name=name, dtype=dtype, **kwargs)
elif is_period_dtype(data) and not is_object_dtype(dtype):
return PeriodIndex(data, copy=copy, name=name, **kwargs)
# extension dtype
elif is_extension_array_dtype(data) or is_extension_array_dtype(dtype):
if not (dtype is None or is_object_dtype(dtype)):
# coerce to the provided dtype
ea_cls = dtype.construct_array_type()
data = ea_cls._from_sequence(data, dtype=dtype, copy=False)
else:
data = np.asarray(data, dtype=object)
# coerce to the object dtype
data = data.astype(object)
return Index(data, dtype=object, copy=copy, name=name, **kwargs)
# index-like
elif isinstance(data, (np.ndarray, Index, ABCSeries)):
if dtype is not None:
# we need to avoid having numpy coerce
# things that look like ints/floats to ints unless
# they are actually ints, e.g. '0' and 0.0
# should not be coerced
# GH 11836
data = _maybe_cast_with_dtype(data, dtype, copy)
dtype = data.dtype # TODO: maybe not for object?
# maybe coerce to a sub-class
if is_signed_integer_dtype(data.dtype):
return Int64Index(data, copy=copy, dtype=dtype, name=name)
elif is_unsigned_integer_dtype(data.dtype):
return UInt64Index(data, copy=copy, dtype=dtype, name=name)
elif is_float_dtype(data.dtype):
return Float64Index(data, copy=copy, dtype=dtype, name=name)
elif issubclass(data.dtype.type, np.bool) or is_bool_dtype(data):
subarr = data.astype("object")
else:
subarr = com.asarray_tuplesafe(data, dtype=object)
# asarray_tuplesafe does not always copy underlying data,
# so need to make sure that this happens
if copy:
subarr = subarr.copy()
if dtype is None:
new_data, new_dtype = _maybe_cast_data_without_dtype(subarr)
if new_dtype is not None:
return cls(
new_data, dtype=new_dtype, copy=False, name=name, **kwargs
)
if kwargs:
raise TypeError(f"Unexpected keyword arguments {repr(set(kwargs))}")
return cls._simple_new(subarr, name, **kwargs)
elif hasattr(data, "__array__"):
return Index(np.asarray(data), dtype=dtype, copy=copy, name=name, **kwargs)
elif data is None or is_scalar(data):
raise cls._scalar_data_error(data)
else:
if tupleize_cols and is_list_like(data):
# GH21470: convert iterable to list before determining if empty
if is_iterator(data):
data = list(data)
if data and all(isinstance(e, tuple) for e in data):
# we must be all tuples, otherwise don't construct
# 10697
from .multi import MultiIndex
return MultiIndex.from_tuples(
data, names=name or kwargs.get("names")
)
# other iterable of some kind
subarr = com.asarray_tuplesafe(data, dtype=object)
return Index(subarr, dtype=dtype, copy=copy, name=name, **kwargs)
"""
NOTE for new Index creation:
- _simple_new: It returns new Index with the same type as the caller.
All metadata (such as name) must be provided by caller's responsibility.
Using _shallow_copy is recommended because it fills these metadata
otherwise specified.
- _shallow_copy: It returns new Index with the same type (using
_simple_new), but fills caller's metadata otherwise specified. Passed
kwargs will overwrite corresponding metadata.
- _shallow_copy_with_infer: It returns new Index inferring its type
from passed values. It fills caller's metadata otherwise specified as the
same as _shallow_copy.
See each method's docstring.
"""
@property
def asi8(self):
"""
Integer representation of the values.
Returns
-------
ndarray
An ndarray with int64 dtype.
"""
return None
@classmethod
def _simple_new(cls, values, name=None, dtype=None):
"""
We require that we have a dtype compat for the values. If we are passed
a non-dtype compat, then coerce using the constructor.
Must be careful not to recurse.
"""
if isinstance(values, (ABCSeries, ABCIndexClass)):
# Index._data must always be an ndarray.
# This is no-copy for when _values is an ndarray,
# which should be always at this point.
values = np.asarray(values._values)
result = object.__new__(cls)
result._data = values
# _index_data is a (temporary?) fix to ensure that the direct data
# manipulation we do in `_libs/reduction.pyx` continues to work.
# We need access to the actual ndarray, since we're messing with
# data buffers and strides. We don't re-use `_ndarray_values`, since
# we actually set this value too.
result._index_data = values
result._name = name
return result._reset_identity()
@cache_readonly
def _constructor(self):
return type(self)
# --------------------------------------------------------------------
# Index Internals Methods
def _get_attributes_dict(self):
"""
Return an attributes dict for my class.
"""
return {k: getattr(self, k, None) for k in self._attributes}
_index_shared_docs[
"_shallow_copy"
] = """
Create a new Index with the same class as the caller, don't copy the
data, use the same object attributes with passed in attributes taking
precedence.
*this is an internal non-public method*
Parameters
----------
values : the values to create the new Index, optional
kwargs : updates the default attributes for this Index
"""
@Appender(_index_shared_docs["_shallow_copy"])
def _shallow_copy(self, values=None, **kwargs):
if values is None:
values = self.values
attributes = self._get_attributes_dict()
attributes.update(kwargs)
if not len(values) and "dtype" not in kwargs:
attributes["dtype"] = self.dtype
# _simple_new expects an the type of self._data
values = getattr(values, "_values", values)
if isinstance(values, ABCDatetimeArray):
# `self.values` returns `self` for tz-aware, so we need to unwrap
# more specifically
values = values.asi8
return self._simple_new(values, **attributes)
def _shallow_copy_with_infer(self, values, **kwargs):
"""
Create a new Index inferring the class with passed value, don't copy
the data, use the same object attributes with passed in attributes
taking precedence.
*this is an internal non-public method*
Parameters
----------
values : the values to create the new Index, optional
kwargs : updates the default attributes for this Index
"""
attributes = self._get_attributes_dict()
attributes.update(kwargs)
attributes["copy"] = False
if not len(values) and "dtype" not in kwargs:
attributes["dtype"] = self.dtype
if self._infer_as_myclass:
try:
return self._constructor(values, **attributes)
except (TypeError, ValueError):
pass
return Index(values, **attributes)
def _update_inplace(self, result, **kwargs):
# guard when called from IndexOpsMixin
raise TypeError("Index can't be updated inplace")
def is_(self, other) -> bool:
"""
More flexible, faster check like ``is`` but that works through views.
Note: this is *not* the same as ``Index.identical()``, which checks
that metadata is also the same.
Parameters
----------
other : object
other object to compare against.
Returns
-------
True if both have same underlying data, False otherwise : bool
"""
# use something other than None to be clearer
return self._id is getattr(other, "_id", Ellipsis) and self._id is not None
def _reset_identity(self):
"""
Initializes or resets ``_id`` attribute with new object.
"""
self._id = _Identity()
return self
def _cleanup(self):
self._engine.clear_mapping()
@cache_readonly
def _engine(self):
# property, for now, slow to look up
# to avoid a reference cycle, bind `_ndarray_values` to a local variable, so
# `self` is not passed into the lambda.
_ndarray_values = self._ndarray_values
return self._engine_type(lambda: _ndarray_values, len(self))
# --------------------------------------------------------------------
# Array-Like Methods
# ndarray compat
def __len__(self) -> int:
"""
Return the length of the Index.
"""
return len(self._data)
def __array__(self, dtype=None):
"""
The array interface, return my values.
"""
return np.asarray(self._data, dtype=dtype)
def __array_wrap__(self, result, context=None):
"""
Gets called after a ufunc.
"""
result = lib.item_from_zerodim(result)
if is_bool_dtype(result) or lib.is_scalar(result):
return result
attrs = self._get_attributes_dict()
return Index(result, **attrs)
@cache_readonly
def dtype(self):
"""
Return the dtype object of the underlying data.
"""
return self._data.dtype
def ravel(self, order="C"):
"""
Return an ndarray of the flattened values of the underlying data.
Returns
-------
numpy.ndarray
Flattened array.
See Also
--------
numpy.ndarray.ravel
"""
return self._ndarray_values.ravel(order=order)
def view(self, cls=None):
# we need to see if we are subclassing an
# index type here
if cls is not None and not hasattr(cls, "_typ"):
result = self._data.view(cls)
else:
result = self._shallow_copy()
if isinstance(result, Index):
result._id = self._id
return result
_index_shared_docs[
"astype"
] = """
Create an Index with values cast to dtypes. The class of a new Index
is determined by dtype. When conversion is impossible, a ValueError
exception is raised.
Parameters
----------
dtype : numpy dtype or pandas type
Note that any signed integer `dtype` is treated as ``'int64'``,
and any unsigned integer `dtype` is treated as ``'uint64'``,
regardless of the size.
copy : bool, default True
By default, astype always returns a newly allocated object.
If copy is set to False and internal requirements on dtype are
satisfied, the original data is used to create a new Index
or the original Index is returned.
Returns
-------
Index
Index with values cast to specified dtype.
"""
@Appender(_index_shared_docs["astype"])
def astype(self, dtype, copy=True):
if is_dtype_equal(self.dtype, dtype):
return self.copy() if copy else self
elif is_categorical_dtype(dtype):
from .category import CategoricalIndex
return CategoricalIndex(self.values, name=self.name, dtype=dtype, copy=copy)
elif is_extension_array_dtype(dtype):
return Index(np.asarray(self), dtype=dtype, copy=copy)
try:
return Index(
self.values.astype(dtype, copy=copy), name=self.name, dtype=dtype
)
except (TypeError, ValueError):
raise TypeError(f"Cannot cast {type(self).__name__} to dtype {dtype}")
_index_shared_docs[
"take"
] = """
Return a new %(klass)s of the values selected by the indices.
For internal compatibility with numpy arrays.
Parameters
----------
indices : list
Indices to be taken.
axis : int, optional
The axis over which to select values, always 0.
allow_fill : bool, default True
fill_value : bool, default None
If allow_fill=True and fill_value is not None, indices specified by
-1 is regarded as NA. If Index doesn't hold NA, raise ValueError.
Returns
-------
numpy.ndarray
Elements of given indices.
See Also
--------
numpy.ndarray.take
"""
@Appender(_index_shared_docs["take"] % _index_doc_kwargs)
def take(self, indices, axis=0, allow_fill=True, fill_value=None, **kwargs):
if kwargs:
nv.validate_take(tuple(), kwargs)
indices = ensure_platform_int(indices)
if self._can_hold_na:
taken = self._assert_take_fillable(
self.values,
indices,
allow_fill=allow_fill,
fill_value=fill_value,
na_value=self._na_value,
)
else:
if allow_fill and fill_value is not None:
cls_name = type(self).__name__
raise ValueError(
f"Unable to fill values because {cls_name} cannot contain NA"
)
taken = self.values.take(indices)
return self._shallow_copy(taken)
def _assert_take_fillable(
self, values, indices, allow_fill=True, fill_value=None, na_value=np.nan
):
"""
Internal method to handle NA filling of take.
"""
indices = ensure_platform_int(indices)
# only fill if we are passing a non-None fill_value
if allow_fill and fill_value is not None:
if (indices < -1).any():
raise ValueError(
"When allow_fill=True and fill_value is not None, "
"all indices must be >= -1"
)
taken = algos.take(
values, indices, allow_fill=allow_fill, fill_value=na_value
)
else:
taken = values.take(indices)
return taken
_index_shared_docs[
"repeat"
] = """
Repeat elements of a %(klass)s.
Returns a new %(klass)s where each element of the current %(klass)s
is repeated consecutively a given number of times.
Parameters
----------
repeats : int or array of ints
The number of repetitions for each element. This should be a
non-negative integer. Repeating 0 times will return an empty
%(klass)s.
axis : None
Must be ``None``. Has no effect but is accepted for compatibility
with numpy.
Returns
-------
repeated_index : %(klass)s
Newly created %(klass)s with repeated elements.
See Also
--------
Series.repeat : Equivalent function for Series.
numpy.repeat : Similar method for :class:`numpy.ndarray`.
Examples
--------
>>> idx = pd.Index(['a', 'b', 'c'])
>>> idx
Index(['a', 'b', 'c'], dtype='object')
>>> idx.repeat(2)
Index(['a', 'a', 'b', 'b', 'c', 'c'], dtype='object')
>>> idx.repeat([1, 2, 3])
Index(['a', 'b', 'b', 'c', 'c', 'c'], dtype='object')
"""
@Appender(_index_shared_docs["repeat"] % _index_doc_kwargs)
def repeat(self, repeats, axis=None):
repeats = ensure_platform_int(repeats)
nv.validate_repeat(tuple(), dict(axis=axis))
return self._shallow_copy(self._values.repeat(repeats))
# --------------------------------------------------------------------
# Copying Methods
_index_shared_docs[
"copy"
] = """
Make a copy of this object. Name and dtype sets those attributes on
the new object.
Parameters
----------
name : str, optional
deep : bool, default False
dtype : numpy dtype or pandas type
Returns
-------
copy : Index
Notes
-----
In most cases, there should be no functional difference from using
``deep``, but if ``deep`` is passed it will attempt to deepcopy.
"""
@Appender(_index_shared_docs["copy"])
def copy(self, name=None, deep=False, dtype=None, **kwargs):
if deep:
new_index = self._shallow_copy(self._data.copy())
else:
new_index = self._shallow_copy()
names = kwargs.get("names")
names = self._validate_names(name=name, names=names, deep=deep)
new_index = new_index.set_names(names)
if dtype:
new_index = new_index.astype(dtype)
return new_index
def __copy__(self, **kwargs):
return self.copy(**kwargs)
def __deepcopy__(self, memo=None):
"""
Parameters
----------
memo, default None
Standard signature. Unused
"""
return self.copy(deep=True)
# --------------------------------------------------------------------
# Rendering Methods
def __repr__(self):
"""
Return a string representation for this object.
"""
klass_name = type(self).__name__
data = self._format_data()
attrs = self._format_attrs()
space = self._format_space()
attrs_str = [f"{k}={v}" for k, v in attrs]
prepr = f",{space}".join(attrs_str)
# no data provided, just attributes
if data is None:
data = ""
res = f"{klass_name}({data}{prepr})"
return res
def _format_space(self):
# using space here controls if the attributes
# are line separated or not (the default)
# max_seq_items = get_option('display.max_seq_items')
# if len(self) > max_seq_items:
# space = "\n%s" % (' ' * (len(klass) + 1))
return " "
@property
def _formatter_func(self):
"""
Return the formatter function.
"""
return default_pprint
def _format_data(self, name=None):
"""
Return the formatted data as a unicode string.
"""
# do we want to justify (only do so for non-objects)
is_justify = not (
self.inferred_type in ("string", "unicode")
or (
self.inferred_type == "categorical" and is_object_dtype(self.categories)
)
)
return format_object_summary(
self, self._formatter_func, is_justify=is_justify, name=name
)
def _format_attrs(self):
"""
Return a list of tuples of the (attr,formatted_value).
"""
return format_object_attrs(self)
def _mpl_repr(self):
# how to represent ourselves to matplotlib
return self.values
def format(self, name=False, formatter=None, **kwargs):
"""
Render a string representation of the Index.
"""
header = []
if name:
header.append(
pprint_thing(self.name, escape_chars=("\t", "\r", "\n"))
if self.name is not None
else ""
)
if formatter is not None:
return header + list(self.map(formatter))
return self._format_with_header(header, **kwargs)
def _format_with_header(self, header, na_rep="NaN", **kwargs):
values = self.values
from pandas.io.formats.format import format_array
if is_categorical_dtype(values.dtype):
values = np.array(values)
elif is_object_dtype(values.dtype):
values = lib.maybe_convert_objects(values, safe=1)
if is_object_dtype(values.dtype):
result = [pprint_thing(x, escape_chars=("\t", "\r", "\n")) for x in values]
# could have nans
mask = isna(values)
if mask.any():
result = np.array(result)
result[mask] = na_rep
result = result.tolist()
else:
result = _trim_front(format_array(values, None, justify="left"))
return header + result
def to_native_types(self, slicer=None, **kwargs):
"""
Format specified values of `self` and return them.
Parameters
----------
slicer : int, array-like
An indexer into `self` that specifies which values
are used in the formatting process.
kwargs : dict
Options for specifying how the values should be formatted.
These options include the following:
1) na_rep : str
The value that serves as a placeholder for NULL values
2) quoting : bool or None
Whether or not there are quoted values in `self`
3) date_format : str
The format used to represent date-like values.
Returns
-------
numpy.ndarray
Formatted values.
"""
values = self
if slicer is not None:
values = values[slicer]
return values._format_native_types(**kwargs)
def _format_native_types(self, na_rep="", quoting=None, **kwargs):
"""
Actually format specific types of the index.
"""
mask = isna(self)
if not self.is_object() and not quoting:
values = np.asarray(self).astype(str)
else:
values = np.array(self, dtype=object, copy=True)
values[mask] = na_rep
return values
def _summary(self, name=None):
"""
Return a summarized representation.
Parameters
----------
name : str
name to use in the summary representation
Returns
-------
String with a summarized representation of the index
"""
if len(self) > 0:
head = self[0]
if hasattr(head, "format") and not isinstance(head, str):
head = head.format()
tail = self[-1]
if hasattr(tail, "format") and not isinstance(tail, str):
tail = tail.format()
index_summary = f", {head} to {tail}"
else:
index_summary = ""
if name is None:
name = type(self).__name__
return f"{name}: {len(self)} entries{index_summary}"
# --------------------------------------------------------------------
# Conversion Methods
def to_flat_index(self):
"""
Identity method.
.. versionadded:: 0.24.0
This is implemented for compatibility with subclass implementations
when chaining.
Returns
-------
pd.Index
Caller.
See Also
--------
MultiIndex.to_flat_index : Subclass implementation.
"""
return self
def to_series(self, index=None, name=None):
"""
Create a Series with both index and values equal to the index keys.
Useful with map for returning an indexer based on an index.
Parameters
----------
index : Index, optional
Index of resulting Series. If None, defaults to original index.
name : str, optional
Dame of resulting Series. If None, defaults to name of original
index.
Returns
-------
Series
The dtype will be based on the type of the Index values.
"""
from pandas import Series
if index is None:
index = self._shallow_copy()
if name is None:
name = self.name
return Series(self.values.copy(), index=index, name=name)
def to_frame(self, index=True, name=None):
"""
Create a DataFrame with a column containing the Index.
.. versionadded:: 0.24.0
Parameters
----------
index : bool, default True
Set the index of the returned DataFrame as the original Index.
name : object, default None
The passed name should substitute for the index name (if it has
one).
Returns
-------
DataFrame
DataFrame containing the original Index data.
See Also
--------
Index.to_series : Convert an Index to a Series.
Series.to_frame : Convert Series to DataFrame.
Examples
--------
>>> idx = pd.Index(['Ant', 'Bear', 'Cow'], name='animal')
>>> idx.to_frame()
animal
animal
Ant Ant
Bear Bear
Cow Cow
By default, the original Index is reused. To enforce a new Index:
>>> idx.to_frame(index=False)
animal
0 Ant
1 Bear
2 Cow
To override the name of the resulting column, specify `name`:
>>> idx.to_frame(index=False, name='zoo')
zoo
0 Ant
1 Bear
2 Cow
"""
from pandas import DataFrame
if name is None:
name = self.name or 0
result = DataFrame({name: self._values.copy()})
if index:
result.index = self
return result
# --------------------------------------------------------------------
# Name-Centric Methods
@property
def name(self):
return self._name
@name.setter
def name(self, value):
if self._no_setting_name:
# Used in MultiIndex.levels to avoid silently ignoring name updates.
raise RuntimeError(
"Cannot set name on a level of a MultiIndex. Use "
"'MultiIndex.set_names' instead."
)
maybe_extract_name(value, None, type(self))
self._name = value
def _validate_names(self, name=None, names=None, deep=False):
"""
Handles the quirks of having a singular 'name' parameter for general
Index and plural 'names' parameter for MultiIndex.
"""
from copy import deepcopy
if names is not None and name is not None:
raise TypeError("Can only provide one of `names` and `name`")
elif names is None and name is None:
return deepcopy(self.names) if deep else self.names
elif names is not None:
if not is_list_like(names):
raise TypeError("Must pass list-like as `names`.")
return names
else:
if not is_list_like(name):
return [name]
return name
def _get_names(self):
return FrozenList((self.name,))
def _set_names(self, values, level=None):
"""
Set new names on index. Each name has to be a hashable type.
Parameters
----------
values : str or sequence
name(s) to set
level : int, level name, or sequence of int/level names (default None)
If the index is a MultiIndex (hierarchical), level(s) to set (None
for all levels). Otherwise level must be None
Raises
------
TypeError if each name is not hashable.
"""
if not is_list_like(values):
raise ValueError("Names must be a list-like")
if len(values) != 1:
raise ValueError(f"Length of new names must be 1, got {len(values)}")
# GH 20527
# All items in 'name' need to be hashable:
for name in values:
if not is_hashable(name):
raise TypeError(f"{type(self).__name__}.name must be a hashable type")
self._name = values[0]
names = property(fset=_set_names, fget=_get_names)
def set_names(self, names, level=None, inplace=False):
"""
Set Index or MultiIndex name.
Able to set new names partially and by level.
Parameters
----------
names : label or list of label
Name(s) to set.
level : int, label or list of int or label, optional
If the index is a MultiIndex, level(s) to set (None for all
levels). Otherwise level must be None.
inplace : bool, default False
Modifies the object directly, instead of creating a new Index or
MultiIndex.
Returns
-------
Index
The same type as the caller or None if inplace is True.
See Also
--------
Index.rename : Able to set new names without level.
Examples
--------
>>> idx = pd.Index([1, 2, 3, 4])
>>> idx
Int64Index([1, 2, 3, 4], dtype='int64')
>>> idx.set_names('quarter')
Int64Index([1, 2, 3, 4], dtype='int64', name='quarter')
>>> idx = pd.MultiIndex.from_product([['python', 'cobra'],
... [2018, 2019]])
>>> idx
MultiIndex([('python', 2018),
('python', 2019),
( 'cobra', 2018),
( 'cobra', 2019)],
)
>>> idx.set_names(['kind', 'year'], inplace=True)
>>> idx
MultiIndex([('python', 2018),
('python', 2019),
( 'cobra', 2018),
( 'cobra', 2019)],
names=['kind', 'year'])
>>> idx.set_names('species', level=0)
MultiIndex([('python', 2018),
('python', 2019),
( 'cobra', 2018),
( 'cobra', 2019)],
names=['species', 'year'])
"""
if level is not None and not isinstance(self, ABCMultiIndex):
raise ValueError("Level must be None for non-MultiIndex")
if level is not None and not is_list_like(level) and is_list_like(names):
raise TypeError("Names must be a string when a single level is provided.")
if not is_list_like(names) and level is None and self.nlevels > 1:
raise TypeError("Must pass list-like as `names`.")
if not is_list_like(names):
names = [names]
if level is not None and not is_list_like(level):
level = [level]
if inplace:
idx = self
else:
idx = self._shallow_copy()
idx._set_names(names, level=level)
if not inplace:
return idx
def rename(self, name, inplace=False):
"""
Alter Index or MultiIndex name.
Able to set new names without level. Defaults to returning new index.
Length of names must match number of levels in MultiIndex.
Parameters
----------
name : label or list of labels
Name(s) to set.
inplace : bool, default False
Modifies the object directly, instead of creating a new Index or
MultiIndex.
Returns
-------
Index
The same type as the caller or None if inplace is True.
See Also
--------
Index.set_names : Able to set new names partially and by level.
Examples
--------
>>> idx = pd.Index(['A', 'C', 'A', 'B'], name='score')
>>> idx.rename('grade')
Index(['A', 'C', 'A', 'B'], dtype='object', name='grade')
>>> idx = pd.MultiIndex.from_product([['python', 'cobra'],
... [2018, 2019]],
... names=['kind', 'year'])
>>> idx
MultiIndex([('python', 2018),
('python', 2019),
( 'cobra', 2018),
( 'cobra', 2019)],
names=['kind', 'year'])
>>> idx.rename(['species', 'year'])
MultiIndex([('python', 2018),
('python', 2019),
( 'cobra', 2018),
( 'cobra', 2019)],
names=['species', 'year'])
>>> idx.rename('species')
Traceback (most recent call last):
TypeError: Must pass list-like as `names`.
"""
return self.set_names([name], inplace=inplace)
# --------------------------------------------------------------------
# Level-Centric Methods
@property
def nlevels(self) -> int:
"""
Number of levels.
"""
return 1
def _sort_levels_monotonic(self):
"""
Compat with MultiIndex.
"""
return self
def _validate_index_level(self, level):
"""
Validate index level.
For single-level Index getting level number is a no-op, but some
verification must be done like in MultiIndex.
"""
if isinstance(level, int):
if level < 0 and level != -1:
raise IndexError(
"Too many levels: Index has only 1 level, "
f"{level} is not a valid level number"
)
elif level > 0:
raise IndexError(
f"Too many levels: Index has only 1 level, not {level + 1}"
)
elif level != self.name:
raise KeyError(
f"Requested level ({level}) does not match index name ({self.name})"
)
def _get_level_number(self, level):
self._validate_index_level(level)
return 0
def sortlevel(self, level=None, ascending=True, sort_remaining=None):
"""
For internal compatibility with with the Index API.
Sort the Index. This is for compat with MultiIndex
Parameters
----------
ascending : bool, default True
False to sort in descending order
level, sort_remaining are compat parameters
Returns
-------
Index
"""
return self.sort_values(return_indexer=True, ascending=ascending)
def _get_level_values(self, level):
"""
Return an Index of values for requested level.
This is primarily useful to get an individual level of values from a
MultiIndex, but is provided on Index as well for compatibility.
Parameters
----------
level : int or str
It is either the integer position or the name of the level.
Returns
-------
Index
Calling object, as there is only one level in the Index.
See Also
--------
MultiIndex.get_level_values : Get values for a level of a MultiIndex.
Notes
-----
For Index, level should be 0, since there are no multiple levels.
Examples
--------
>>> idx = pd.Index(list('abc'))
>>> idx
Index(['a', 'b', 'c'], dtype='object')
Get level values by supplying `level` as integer:
>>> idx.get_level_values(0)
Index(['a', 'b', 'c'], dtype='object')
"""
self._validate_index_level(level)
return self
get_level_values = _get_level_values
def droplevel(self, level=0):
"""
Return index with requested level(s) removed.
If resulting index has only 1 level left, the result will be
of Index type, not MultiIndex.
.. versionadded:: 0.23.1 (support for non-MultiIndex)
Parameters
----------
level : int, str, or list-like, default 0
If a string is given, must be the name of a level
If list-like, elements must be names or indexes of levels.
Returns
-------
Index or MultiIndex
"""
if not isinstance(level, (tuple, list)):
level = [level]
levnums = sorted(self._get_level_number(lev) for lev in level)[::-1]
if len(level) == 0:
return self
if len(level) >= self.nlevels:
raise ValueError(
f"Cannot remove {len(level)} levels from an index with {self.nlevels} "
"levels: at least one level must be left."
)
# The two checks above guarantee that here self is a MultiIndex
new_levels = list(self.levels)
new_codes = list(self.codes)
new_names = list(self.names)
for i in levnums:
new_levels.pop(i)
new_codes.pop(i)
new_names.pop(i)
if len(new_levels) == 1:
# set nan if needed
mask = new_codes[0] == -1
result = new_levels[0].take(new_codes[0])
if mask.any():
result = result.putmask(mask, np.nan)
result._name = new_names[0]
return result
else:
from .multi import MultiIndex
return MultiIndex(
levels=new_levels,
codes=new_codes,
names=new_names,
verify_integrity=False,
)
_index_shared_docs[
"_get_grouper_for_level"
] = """
Get index grouper corresponding to an index level
Parameters
----------
mapper: Group mapping function or None
Function mapping index values to groups
level : int or None
Index level
Returns
-------
grouper : Index
Index of values to group on.
labels : ndarray of int or None
Array of locations in level_index.
uniques : Index or None
Index of unique values for level.
"""
@Appender(_index_shared_docs["_get_grouper_for_level"])
def _get_grouper_for_level(self, mapper, level=None):
assert level is None or level == 0
if mapper is None:
grouper = self
else:
grouper = self.map(mapper)
return grouper, None, None
# --------------------------------------------------------------------
# Introspection Methods
@property
def is_monotonic(self) -> bool:
"""
Alias for is_monotonic_increasing.
"""
return self.is_monotonic_increasing
@property
def is_monotonic_increasing(self):
"""
Return if the index is monotonic increasing (only equal or
increasing) values.
Examples
--------
>>> Index([1, 2, 3]).is_monotonic_increasing
True
>>> Index([1, 2, 2]).is_monotonic_increasing
True
>>> Index([1, 3, 2]).is_monotonic_increasing
False
"""
return self._engine.is_monotonic_increasing
@property
def is_monotonic_decreasing(self) -> bool:
"""
Return if the index is monotonic decreasing (only equal or
decreasing) values.
Examples
--------
>>> Index([3, 2, 1]).is_monotonic_decreasing
True
>>> Index([3, 2, 2]).is_monotonic_decreasing
True
>>> Index([3, 1, 2]).is_monotonic_decreasing
False
"""
return self._engine.is_monotonic_decreasing
@property
def _is_strictly_monotonic_increasing(self) -> bool:
"""
Return if the index is strictly monotonic increasing
(only increasing) values.
Examples
--------
>>> Index([1, 2, 3])._is_strictly_monotonic_increasing
True
>>> Index([1, 2, 2])._is_strictly_monotonic_increasing
False
>>> Index([1, 3, 2])._is_strictly_monotonic_increasing
False
"""
return self.is_unique and self.is_monotonic_increasing
@property
def _is_strictly_monotonic_decreasing(self) -> bool:
"""
Return if the index is strictly monotonic decreasing
(only decreasing) values.
Examples
--------
>>> Index([3, 2, 1])._is_strictly_monotonic_decreasing
True
>>> Index([3, 2, 2])._is_strictly_monotonic_decreasing
False
>>> Index([3, 1, 2])._is_strictly_monotonic_decreasing
False
"""
return self.is_unique and self.is_monotonic_decreasing
@cache_readonly
def is_unique(self) -> bool:
"""
Return if the index has unique values.
"""
return self._engine.is_unique
@property
def has_duplicates(self) -> bool:
return not self.is_unique
def is_boolean(self) -> bool:
return self.inferred_type in ["boolean"]
def is_integer(self) -> bool:
return self.inferred_type in ["integer"]
def is_floating(self) -> bool:
return self.inferred_type in ["floating", "mixed-integer-float", "integer-na"]
def is_numeric(self) -> bool:
return self.inferred_type in ["integer", "floating"]
def is_object(self) -> bool:
return is_object_dtype(self.dtype)
def is_categorical(self) -> bool:
"""
Check if the Index holds categorical data.
Returns
-------
boolean
True if the Index is categorical.
See Also
--------
CategoricalIndex : Index for categorical data.
Examples
--------
>>> idx = pd.Index(["Watermelon", "Orange", "Apple",
... "Watermelon"]).astype("category")
>>> idx.is_categorical()
True
>>> idx = pd.Index([1, 3, 5, 7])
>>> idx.is_categorical()
False
>>> s = pd.Series(["Peter", "Victor", "Elisabeth", "Mar"])
>>> s
0 Peter
1 Victor
2 Elisabeth
3 Mar
dtype: object
>>> s.index.is_categorical()
False
"""
return self.inferred_type in ["categorical"]
def is_interval(self) -> bool:
return self.inferred_type in ["interval"]
def is_mixed(self) -> bool:
return self.inferred_type in ["mixed"]
def holds_integer(self):
"""
Whether the type is an integer type.
"""
return self.inferred_type in ["integer", "mixed-integer"]
@cache_readonly
def inferred_type(self):
"""
Return a string of the type inferred from the values.
"""
return lib.infer_dtype(self, skipna=False)
@cache_readonly
def is_all_dates(self) -> bool:
return is_datetime_array(ensure_object(self.values))
# --------------------------------------------------------------------
# Pickle Methods
def __reduce__(self):
d = dict(data=self._data)
d.update(self._get_attributes_dict())
return _new_Index, (type(self), d), None
def __setstate__(self, state):
"""
Necessary for making this object picklable.
"""
if isinstance(state, dict):
self._data = state.pop("data")
for k, v in state.items():
setattr(self, k, v)
elif isinstance(state, tuple):
if len(state) == 2:
nd_state, own_state = state
data = np.empty(nd_state[1], dtype=nd_state[2])
np.ndarray.__setstate__(data, nd_state)
self._name = own_state[0]
else: # pragma: no cover
data = np.empty(state)
np.ndarray.__setstate__(data, state)
self._data = data
self._reset_identity()
else:
raise Exception("invalid pickle state")
_unpickle_compat = __setstate__
# --------------------------------------------------------------------
# Null Handling Methods
_na_value = np.nan
"""The expected NA value to use with this index."""
@cache_readonly
def _isnan(self):
"""
Return if each value is NaN.
"""
if self._can_hold_na:
return isna(self)
else:
# shouldn't reach to this condition by checking hasnans beforehand
values = np.empty(len(self), dtype=np.bool_)
values.fill(False)
return values
@cache_readonly
def _nan_idxs(self):
if self._can_hold_na:
return self._isnan.nonzero()[0]
else:
return np.array([], dtype=np.int64)
@cache_readonly
def hasnans(self):
"""
Return if I have any nans; enables various perf speedups.
"""
if self._can_hold_na:
return bool(self._isnan.any())
else:
return False
def isna(self):
"""
Detect missing values.
Return a boolean same-sized object indicating if the values are NA.
NA values, such as ``None``, :attr:`numpy.NaN` or :attr:`pd.NaT`, get
mapped to ``True`` values.
Everything else get mapped to ``False`` values. Characters such as
empty strings `''` or :attr:`numpy.inf` are not considered NA values
(unless you set ``pandas.options.mode.use_inf_as_na = True``).
Returns
-------
numpy.ndarray
A boolean array of whether my values are NA.
See Also
--------
Index.notna : Boolean inverse of isna.
Index.dropna : Omit entries with missing values.
isna : Top-level isna.
Series.isna : Detect missing values in Series object.
Examples
--------
Show which entries in a pandas.Index are NA. The result is an
array.
>>> idx = pd.Index([5.2, 6.0, np.NaN])
>>> idx
Float64Index([5.2, 6.0, nan], dtype='float64')
>>> idx.isna()
array([False, False, True], dtype=bool)
Empty strings are not considered NA values. None is considered an NA
value.
>>> idx = pd.Index(['black', '', 'red', None])
>>> idx
Index(['black', '', 'red', None], dtype='object')
>>> idx.isna()
array([False, False, False, True], dtype=bool)
For datetimes, `NaT` (Not a Time) is considered as an NA value.
>>> idx = pd.DatetimeIndex([pd.Timestamp('1940-04-25'),
... pd.Timestamp(''), None, pd.NaT])
>>> idx
DatetimeIndex(['1940-04-25', 'NaT', 'NaT', 'NaT'],
dtype='datetime64[ns]', freq=None)
>>> idx.isna()
array([False, True, True, True], dtype=bool)
"""
return self._isnan
isnull = isna
def notna(self):
"""
Detect existing (non-missing) values.
Return a boolean same-sized object indicating if the values are not NA.
Non-missing values get mapped to ``True``. Characters such as empty
strings ``''`` or :attr:`numpy.inf` are not considered NA values
(unless you set ``pandas.options.mode.use_inf_as_na = True``).
NA values, such as None or :attr:`numpy.NaN`, get mapped to ``False``
values.
Returns
-------
numpy.ndarray
Boolean array to indicate which entries are not NA.
See Also
--------
Index.notnull : Alias of notna.
Index.isna: Inverse of notna.
notna : Top-level notna.
Examples
--------
Show which entries in an Index are not NA. The result is an
array.
>>> idx = pd.Index([5.2, 6.0, np.NaN])
>>> idx
Float64Index([5.2, 6.0, nan], dtype='float64')
>>> idx.notna()
array([ True, True, False])
Empty strings are not considered NA values. None is considered a NA
value.
>>> idx = pd.Index(['black', '', 'red', None])
>>> idx
Index(['black', '', 'red', None], dtype='object')
>>> idx.notna()
array([ True, True, True, False])
"""
return ~self.isna()
notnull = notna
_index_shared_docs[
"fillna"
] = """
Fill NA/NaN values with the specified value.
Parameters
----------
value : scalar
Scalar value to use to fill holes (e.g. 0).
This value cannot be a list-likes.
downcast : dict, default is None
a dict of item->dtype of what to downcast if possible,
or the string 'infer' which will try to downcast to an appropriate
equal type (e.g. float64 to int64 if possible).
Returns
-------
filled : Index
"""
@Appender(_index_shared_docs["fillna"])
def fillna(self, value=None, downcast=None):
self._assert_can_do_op(value)
if self.hasnans:
result = self.putmask(self._isnan, value)
if downcast is None:
# no need to care metadata other than name
# because it can't have freq if
return Index(result, name=self.name)
return self._shallow_copy()
_index_shared_docs[
"dropna"
] = """
Return Index without NA/NaN values.
Parameters
----------
how : {'any', 'all'}, default 'any'
If the Index is a MultiIndex, drop the value when any or all levels
are NaN.
Returns
-------
valid : Index
"""
@Appender(_index_shared_docs["dropna"])
def dropna(self, how="any"):
if how not in ("any", "all"):
raise ValueError(f"invalid how option: {how}")
if self.hasnans:
return self._shallow_copy(self.values[~self._isnan])
return self._shallow_copy()
# --------------------------------------------------------------------
# Uniqueness Methods
_index_shared_docs[
"index_unique"
] = """
Return unique values in the index. Uniques are returned in order
of appearance, this does NOT sort.
Parameters
----------
level : int or str, optional, default None
Only return values from specified level (for MultiIndex).
.. versionadded:: 0.23.0
Returns
-------
Index without duplicates
See Also
--------
unique
Series.unique
"""
@Appender(_index_shared_docs["index_unique"] % _index_doc_kwargs)
def unique(self, level=None):
if level is not None:
self._validate_index_level(level)
result = super().unique()
return self._shallow_copy(result)
def drop_duplicates(self, keep="first"):
"""
Return Index with duplicate values removed.
Parameters
----------
keep : {'first', 'last', ``False``}, default 'first'
- 'first' : Drop duplicates except for the first occurrence.
- 'last' : Drop duplicates except for the last occurrence.
- ``False`` : Drop all duplicates.
Returns
-------
deduplicated : Index
See Also
--------
Series.drop_duplicates : Equivalent method on Series.
DataFrame.drop_duplicates : Equivalent method on DataFrame.
Index.duplicated : Related method on Index, indicating duplicate
Index values.
Examples
--------
Generate an pandas.Index with duplicate values.
>>> idx = pd.Index(['lama', 'cow', 'lama', 'beetle', 'lama', 'hippo'])
The `keep` parameter controls which duplicate values are removed.
The value 'first' keeps the first occurrence for each
set of duplicated entries. The default value of keep is 'first'.
>>> idx.drop_duplicates(keep='first')
Index(['lama', 'cow', 'beetle', 'hippo'], dtype='object')
The value 'last' keeps the last occurrence for each set of duplicated
entries.
>>> idx.drop_duplicates(keep='last')
Index(['cow', 'beetle', 'lama', 'hippo'], dtype='object')
The value ``False`` discards all sets of duplicated entries.
>>> idx.drop_duplicates(keep=False)
Index(['cow', 'beetle', 'hippo'], dtype='object')
"""
return super().drop_duplicates(keep=keep)
def duplicated(self, keep="first"):
"""
Indicate duplicate index values.
Duplicated values are indicated as ``True`` values in the resulting
array. Either all duplicates, all except the first, or all except the
last occurrence of duplicates can be indicated.
Parameters
----------
keep : {'first', 'last', False}, default 'first'
The value or values in a set of duplicates to mark as missing.
- 'first' : Mark duplicates as ``True`` except for the first
occurrence.
- 'last' : Mark duplicates as ``True`` except for the last
occurrence.
- ``False`` : Mark all duplicates as ``True``.
Returns
-------
numpy.ndarray
See Also
--------
Series.duplicated : Equivalent method on pandas.Series.
DataFrame.duplicated : Equivalent method on pandas.DataFrame.
Index.drop_duplicates : Remove duplicate values from Index.
Examples
--------
By default, for each set of duplicated values, the first occurrence is
set to False and all others to True:
>>> idx = pd.Index(['lama', 'cow', 'lama', 'beetle', 'lama'])
>>> idx.duplicated()
array([False, False, True, False, True])
which is equivalent to
>>> idx.duplicated(keep='first')
array([False, False, True, False, True])
By using 'last', the last occurrence of each set of duplicated values
is set on False and all others on True:
>>> idx.duplicated(keep='last')
array([ True, False, True, False, False])
By setting keep on ``False``, all duplicates are True:
>>> idx.duplicated(keep=False)
array([ True, False, True, False, True])
"""
return super().duplicated(keep=keep)
def _get_unique_index(self, dropna=False):
"""
Returns an index containing unique values.
Parameters
----------
dropna : bool
If True, NaN values are dropped.
Returns
-------
uniques : index
"""
if self.is_unique and not dropna:
return self
values = self.values
if not self.is_unique:
values = self.unique()
if dropna:
try:
if self.hasnans:
values = values[~isna(values)]
except NotImplementedError:
pass
return self._shallow_copy(values)
# --------------------------------------------------------------------
# Arithmetic & Logical Methods
def __add__(self, other):
if isinstance(other, (ABCSeries, ABCDataFrame)):
return NotImplemented
from pandas import Series
return Index(Series(self) + other)
def __radd__(self, other):
from pandas import Series
return Index(other + Series(self))
def __iadd__(self, other):
# alias for __add__
return self + other
def __sub__(self, other):
return Index(np.array(self) - other)
def __rsub__(self, other):
# wrap Series to ensure we pin name correctly
from pandas import Series
return Index(other - Series(self))
def __and__(self, other):
return self.intersection(other)
def __or__(self, other):
return self.union(other)
def __xor__(self, other):
return self.symmetric_difference(other)
def __nonzero__(self):
raise ValueError(
f"The truth value of a {type(self).__name__} is ambiguous. "
"Use a.empty, a.bool(), a.item(), a.any() or a.all()."
)
__bool__ = __nonzero__
# --------------------------------------------------------------------
# Set Operation Methods
def _get_reconciled_name_object(self, other):
"""
If the result of a set operation will be self,
return self, unless the name changes, in which
case make a shallow copy of self.
"""
name = get_op_result_name(self, other)
if self.name != name:
return self._shallow_copy(name=name)
return self
def _union_incompatible_dtypes(self, other, sort):
"""
Casts this and other index to object dtype to allow the formation
of a union between incompatible types.
Parameters
----------
other : Index or array-like
sort : False or None, default False
Whether to sort the resulting index.
* False : do not sort the result.
* None : sort the result, except when `self` and `other` are equal
or when the values cannot be compared.
Returns
-------
Index
"""
this = self.astype(object, copy=False)
# cast to Index for when `other` is list-like
other = Index(other).astype(object, copy=False)
return Index.union(this, other, sort=sort).astype(object, copy=False)
def _is_compatible_with_other(self, other):
"""
Check whether this and the other dtype are compatible with each other.
Meaning a union can be formed between them without needing to be cast
to dtype object.
Parameters
----------
other : Index or array-like
Returns
-------
bool
"""
return type(self) is type(other) and is_dtype_equal(self.dtype, other.dtype)
def _validate_sort_keyword(self, sort):
if sort not in [None, False]:
raise ValueError(
"The 'sort' keyword only takes the values of "
f"None or False; {sort} was passed."
)
def union(self, other, sort=None):
"""
Form the union of two Index objects.
If the Index objects are incompatible, both Index objects will be
cast to dtype('object') first.
.. versionchanged:: 0.25.0
Parameters
----------
other : Index or array-like
sort : bool or None, default None
Whether to sort the resulting Index.
* None : Sort the result, except when
1. `self` and `other` are equal.
2. `self` or `other` has length 0.
3. Some values in `self` or `other` cannot be compared.
A RuntimeWarning is issued in this case.
* False : do not sort the result.
.. versionadded:: 0.24.0
.. versionchanged:: 0.24.1
Changed the default value from ``True`` to ``None``
(without change in behaviour).
Returns
-------
union : Index
Examples
--------
Union matching dtypes
>>> idx1 = pd.Index([1, 2, 3, 4])
>>> idx2 = pd.Index([3, 4, 5, 6])
>>> idx1.union(idx2)
Int64Index([1, 2, 3, 4, 5, 6], dtype='int64')
Union mismatched dtypes
>>> idx1 = pd.Index(['a', 'b', 'c', 'd'])
>>> idx2 = pd.Index([1, 2, 3, 4])
>>> idx1.union(idx2)
Index(['a', 'b', 'c', 'd', 1, 2, 3, 4], dtype='object')
"""
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
if not self._is_compatible_with_other(other):
return self._union_incompatible_dtypes(other, sort=sort)
return self._union(other, sort=sort)
def _union(self, other, sort):
"""
Specific union logic should go here. In subclasses, union behavior
should be overwritten here rather than in `self.union`.
Parameters
----------
other : Index or array-like
sort : False or None, default False
Whether to sort the resulting index.
* False : do not sort the result.
* None : sort the result, except when `self` and `other` are equal
or when the values cannot be compared.
Returns
-------
Index
"""
if not len(other) or self.equals(other):
return self._get_reconciled_name_object(other)
if not len(self):
return other._get_reconciled_name_object(self)
# TODO(EA): setops-refactor, clean all this up
if is_period_dtype(self) or is_datetime64tz_dtype(self):
lvals = self._ndarray_values
else:
lvals = self._values
if is_period_dtype(other) or is_datetime64tz_dtype(other):
rvals = other._ndarray_values
else:
rvals = other._values
if sort is None and self.is_monotonic and other.is_monotonic:
try:
result = self._outer_indexer(lvals, rvals)[0]
except TypeError:
# incomparable objects
result = list(lvals)
# worth making this faster? a very unusual case
value_set = set(lvals)
result.extend([x for x in rvals if x not in value_set])
else:
# find indexes of things in "other" that are not in "self"
if self.is_unique:
indexer = self.get_indexer(other)
indexer = (indexer == -1).nonzero()[0]
else:
indexer = algos.unique1d(self.get_indexer_non_unique(other)[1])
if len(indexer) > 0:
other_diff = algos.take_nd(rvals, indexer, allow_fill=False)
result = concat_compat((lvals, other_diff))
else:
result = lvals
if sort is None:
try:
result = algos.safe_sort(result)
except TypeError as err:
warnings.warn(
f"{err}, sort order is undefined for incomparable objects",
RuntimeWarning,
stacklevel=3,
)
# for subclasses
return self._wrap_setop_result(other, result)
def _wrap_setop_result(self, other, result):
return self._constructor(result, name=get_op_result_name(self, other))
_index_shared_docs[
"intersection"
] = """
Form the intersection of two Index objects.
This returns a new Index with elements common to the index and `other`.
Parameters
----------
other : Index or array-like
sort : False or None, default False
Whether to sort the resulting index.
* False : do not sort the result.
* None : sort the result, except when `self` and `other` are equal
or when the values cannot be compared.
.. versionadded:: 0.24.0
.. versionchanged:: 0.24.1
Changed the default from ``True`` to ``False``, to match
the behaviour of 0.23.4 and earlier.
Returns
-------
intersection : Index
Examples
--------
>>> idx1 = pd.Index([1, 2, 3, 4])
>>> idx2 = pd.Index([3, 4, 5, 6])
>>> idx1.intersection(idx2)
Int64Index([3, 4], dtype='int64')
"""
# TODO: standardize return type of non-union setops type(self vs other)
@Appender(_index_shared_docs["intersection"])
def intersection(self, other, sort=False):
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
other = ensure_index(other)
if self.equals(other):
return self._get_reconciled_name_object(other)
if not is_dtype_equal(self.dtype, other.dtype):
this = self.astype("O")
other = other.astype("O")
return this.intersection(other, sort=sort)
# TODO(EA): setops-refactor, clean all this up
if is_period_dtype(self):
lvals = self._ndarray_values
else:
lvals = self._values
if is_period_dtype(other):
rvals = other._ndarray_values
else:
rvals = other._values
if self.is_monotonic and other.is_monotonic:
try:
result = self._inner_indexer(lvals, rvals)[0]
return self._wrap_setop_result(other, result)
except TypeError:
pass
try:
indexer = Index(rvals).get_indexer(lvals)
indexer = indexer.take((indexer != -1).nonzero()[0])
except (InvalidIndexError, IncompatibleFrequency):
# InvalidIndexError raised by get_indexer if non-unique
# IncompatibleFrequency raised by PeriodIndex.get_indexer
indexer = algos.unique1d(Index(rvals).get_indexer_non_unique(lvals)[0])
indexer = indexer[indexer != -1]
taken = other.take(indexer)
if sort is None:
taken = algos.safe_sort(taken.values)
if self.name != other.name:
name = None
else:
name = self.name
return self._shallow_copy(taken, name=name)
if self.name != other.name:
taken.name = None
return taken
def difference(self, other, sort=None):
"""
Return a new Index with elements from the index that are not in
`other`.
This is the set difference of two Index objects.
Parameters
----------
other : Index or array-like
sort : False or None, default None
Whether to sort the resulting index. By default, the
values are attempted to be sorted, but any TypeError from
incomparable elements is caught by pandas.
* None : Attempt to sort the result, but catch any TypeErrors
from comparing incomparable elements.
* False : Do not sort the result.
.. versionadded:: 0.24.0
.. versionchanged:: 0.24.1
Changed the default value from ``True`` to ``None``
(without change in behaviour).
Returns
-------
difference : Index
Examples
--------
>>> idx1 = pd.Index([2, 1, 3, 4])
>>> idx2 = pd.Index([3, 4, 5, 6])
>>> idx1.difference(idx2)
Int64Index([1, 2], dtype='int64')
>>> idx1.difference(idx2, sort=False)
Int64Index([2, 1], dtype='int64')
"""
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
if self.equals(other):
# pass an empty np.ndarray with the appropriate dtype
return self._shallow_copy(self._data[:0])
other, result_name = self._convert_can_do_setop(other)
this = self._get_unique_index()
indexer = this.get_indexer(other)
indexer = indexer.take((indexer != -1).nonzero()[0])
label_diff = np.setdiff1d(np.arange(this.size), indexer, assume_unique=True)
the_diff = this.values.take(label_diff)
if sort is None:
try:
the_diff = algos.safe_sort(the_diff)
except TypeError:
pass
return this._shallow_copy(the_diff, name=result_name)
def symmetric_difference(self, other, result_name=None, sort=None):
"""
Compute the symmetric difference of two Index objects.
Parameters
----------
other : Index or array-like
result_name : str
sort : False or None, default None
Whether to sort the resulting index. By default, the
values are attempted to be sorted, but any TypeError from
incomparable elements is caught by pandas.
* None : Attempt to sort the result, but catch any TypeErrors
from comparing incomparable elements.
* False : Do not sort the result.
.. versionadded:: 0.24.0
.. versionchanged:: 0.24.1
Changed the default value from ``True`` to ``None``
(without change in behaviour).
Returns
-------
symmetric_difference : Index
Notes
-----
``symmetric_difference`` contains elements that appear in either
``idx1`` or ``idx2`` but not both. Equivalent to the Index created by
``idx1.difference(idx2) | idx2.difference(idx1)`` with duplicates
dropped.
Examples
--------
>>> idx1 = pd.Index([1, 2, 3, 4])
>>> idx2 = pd.Index([2, 3, 4, 5])
>>> idx1.symmetric_difference(idx2)
Int64Index([1, 5], dtype='int64')
You can also use the ``^`` operator:
>>> idx1 ^ idx2
Int64Index([1, 5], dtype='int64')
"""
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
other, result_name_update = self._convert_can_do_setop(other)
if result_name is None:
result_name = result_name_update
this = self._get_unique_index()
other = other._get_unique_index()
indexer = this.get_indexer(other)
# {this} minus {other}
common_indexer = indexer.take((indexer != -1).nonzero()[0])
left_indexer = np.setdiff1d(
np.arange(this.size), common_indexer, assume_unique=True
)
left_diff = this.values.take(left_indexer)
# {other} minus {this}
right_indexer = (indexer == -1).nonzero()[0]
right_diff = other.values.take(right_indexer)
the_diff = concat_compat([left_diff, right_diff])
if sort is None:
try:
the_diff = algos.safe_sort(the_diff)
except TypeError:
pass
attribs = self._get_attributes_dict()
attribs["name"] = result_name
if "freq" in attribs:
attribs["freq"] = None
return self._shallow_copy_with_infer(the_diff, **attribs)
def _assert_can_do_setop(self, other):
if not is_list_like(other):
raise TypeError("Input must be Index or array-like")
return True
def _convert_can_do_setop(self, other):
if not isinstance(other, Index):
other = Index(other, name=self.name)
result_name = self.name
else:
result_name = get_op_result_name(self, other)
return other, result_name
# --------------------------------------------------------------------
# Indexing Methods
_index_shared_docs[
"get_loc"
] = """
Get integer location, slice or boolean mask for requested label.
Parameters
----------
key : label
method : {None, 'pad'/'ffill', 'backfill'/'bfill', 'nearest'}, optional
* default: exact matches only.
* pad / ffill: find the PREVIOUS index value if no exact match.
* backfill / bfill: use NEXT index value if no exact match
* nearest: use the NEAREST index value if no exact match. Tied
distances are broken by preferring the larger index value.
tolerance : int or float, optional
Maximum distance from index value for inexact matches. The value of
the index at the matching location most satisfy the equation
``abs(index[loc] - key) <= tolerance``.
.. versionadded:: 0.21.0 (list-like tolerance)
Returns
-------
loc : int if unique index, slice if monotonic index, else mask
Examples
--------
>>> unique_index = pd.Index(list('abc'))
>>> unique_index.get_loc('b')
1
>>> monotonic_index = pd.Index(list('abbc'))
>>> monotonic_index.get_loc('b')
slice(1, 3, None)
>>> non_monotonic_index = pd.Index(list('abcb'))
>>> non_monotonic_index.get_loc('b')
array([False, True, False, True], dtype=bool)
"""
@Appender(_index_shared_docs["get_loc"])
def get_loc(self, key, method=None, tolerance=None):
if method is None:
if tolerance is not None:
raise ValueError(
"tolerance argument only valid if using pad, "
"backfill or nearest lookups"
)
try:
return self._engine.get_loc(key)
except KeyError:
return self._engine.get_loc(self._maybe_cast_indexer(key))
indexer = self.get_indexer([key], method=method, tolerance=tolerance)
if indexer.ndim > 1 or indexer.size > 1:
raise TypeError("get_loc requires scalar valued input")
loc = indexer.item()
if loc == -1:
raise KeyError(key)
return loc
_index_shared_docs[
"get_indexer"
] = """
Compute indexer and mask for new index given the current index. The
indexer should be then used as an input to ndarray.take to align the
current data to the new index.
Parameters
----------
target : %(target_klass)s
method : {None, 'pad'/'ffill', 'backfill'/'bfill', 'nearest'}, optional
* default: exact matches only.
* pad / ffill: find the PREVIOUS index value if no exact match.
* backfill / bfill: use NEXT index value if no exact match
* nearest: use the NEAREST index value if no exact match. Tied
distances are broken by preferring the larger index value.
limit : int, optional
Maximum number of consecutive labels in ``target`` to match for
inexact matches.
tolerance : optional
Maximum distance between original and new labels for inexact
matches. The values of the index at the matching locations most
satisfy the equation ``abs(index[indexer] - target) <= tolerance``.
Tolerance may be a scalar value, which applies the same tolerance
to all values, or list-like, which applies variable tolerance per
element. List-like includes list, tuple, array, Series, and must be
the same size as the index and its dtype must exactly match the
index's type.
.. versionadded:: 0.21.0 (list-like tolerance)
Returns
-------
indexer : ndarray of int
Integers from 0 to n - 1 indicating that the index at these
positions matches the corresponding target values. Missing values
in the target are marked by -1.
%(raises_section)s
Examples
--------
>>> index = pd.Index(['c', 'a', 'b'])
>>> index.get_indexer(['a', 'b', 'x'])
array([ 1, 2, -1])
Notice that the return value is an array of locations in ``index``
and ``x`` is marked by -1, as it is not in ``index``.
"""
@Appender(_index_shared_docs["get_indexer"] % _index_doc_kwargs)
def get_indexer(self, target, method=None, limit=None, tolerance=None):
method = missing.clean_reindex_fill_method(method)
target = ensure_index(target)
if tolerance is not None:
tolerance = self._convert_tolerance(tolerance, target)
# Treat boolean labels passed to a numeric index as not found. Without
# this fix False and True would be treated as 0 and 1 respectively.
# (GH #16877)
if target.is_boolean() and self.is_numeric():
return ensure_platform_int(np.repeat(-1, target.size))
pself, ptarget = self._maybe_promote(target)
if pself is not self or ptarget is not target:
return pself.get_indexer(
ptarget, method=method, limit=limit, tolerance=tolerance
)
if not is_dtype_equal(self.dtype, target.dtype):
this = self.astype(object)
target = target.astype(object)
return this.get_indexer(
target, method=method, limit=limit, tolerance=tolerance
)
if not self.is_unique:
raise InvalidIndexError(
"Reindexing only valid with uniquely valued Index objects"
)
if method == "pad" or method == "backfill":
indexer = self._get_fill_indexer(target, method, limit, tolerance)
elif method == "nearest":
indexer = self._get_nearest_indexer(target, limit, tolerance)
else:
if tolerance is not None:
raise ValueError(
"tolerance argument only valid if doing pad, "
"backfill or nearest reindexing"
)
if limit is not None:
raise ValueError(
"limit argument only valid if doing pad, "
"backfill or nearest reindexing"
)
indexer = self._engine.get_indexer(target._ndarray_values)
return ensure_platform_int(indexer)
def _convert_tolerance(self, tolerance, target):
# override this method on subclasses
tolerance = np.asarray(tolerance)
if target.size != tolerance.size and tolerance.size > 1:
raise ValueError("list-like tolerance size must match target index size")
return tolerance
def _get_fill_indexer(self, target, method, limit=None, tolerance=None):
if self.is_monotonic_increasing and target.is_monotonic_increasing:
method = (
self._engine.get_pad_indexer
if method == "pad"
else self._engine.get_backfill_indexer
)
indexer = method(target._ndarray_values, limit)
else:
indexer = self._get_fill_indexer_searchsorted(target, method, limit)
if tolerance is not None:
indexer = self._filter_indexer_tolerance(
target._ndarray_values, indexer, tolerance
)
return indexer
def _get_fill_indexer_searchsorted(self, target, method, limit=None):
"""
Fallback pad/backfill get_indexer that works for monotonic decreasing
indexes and non-monotonic targets.
"""
if limit is not None:
raise ValueError(
f"limit argument for {repr(method)} method only well-defined "
"if index and target are monotonic"
)
side = "left" if method == "pad" else "right"
# find exact matches first (this simplifies the algorithm)
indexer = self.get_indexer(target)
nonexact = indexer == -1
indexer[nonexact] = self._searchsorted_monotonic(target[nonexact], side)
if side == "left":
# searchsorted returns "indices into a sorted array such that,
# if the corresponding elements in v were inserted before the
# indices, the order of a would be preserved".
# Thus, we need to subtract 1 to find values to the left.
indexer[nonexact] -= 1
# This also mapped not found values (values of 0 from
# np.searchsorted) to -1, which conveniently is also our
# sentinel for missing values
else:
# Mark indices to the right of the largest value as not found
indexer[indexer == len(self)] = -1
return indexer
def _get_nearest_indexer(self, target, limit, tolerance):
"""
Get the indexer for the nearest index labels; requires an index with
values that can be subtracted from each other (e.g., not strings or
tuples).
"""
left_indexer = self.get_indexer(target, "pad", limit=limit)
right_indexer = self.get_indexer(target, "backfill", limit=limit)
target = np.asarray(target)
left_distances = abs(self.values[left_indexer] - target)
right_distances = abs(self.values[right_indexer] - target)
op = operator.lt if self.is_monotonic_increasing else operator.le
indexer = np.where(
op(left_distances, right_distances) | (right_indexer == -1),
left_indexer,
right_indexer,
)
if tolerance is not None:
indexer = self._filter_indexer_tolerance(target, indexer, tolerance)
return indexer
def _filter_indexer_tolerance(self, target, indexer, tolerance):
distance = abs(self.values[indexer] - target)
indexer = np.where(distance <= tolerance, indexer, -1)
return indexer
# --------------------------------------------------------------------
# Indexer Conversion Methods
_index_shared_docs[
"_convert_scalar_indexer"
] = """
Convert a scalar indexer.
Parameters
----------
key : label of the slice bound
kind : {'ix', 'loc', 'getitem', 'iloc'} or None
"""
@Appender(_index_shared_docs["_convert_scalar_indexer"])
def _convert_scalar_indexer(self, key, kind=None):
assert kind in ["ix", "loc", "getitem", "iloc", None]
if kind == "iloc":
return self._validate_indexer("positional", key, kind)
if len(self) and not isinstance(self, ABCMultiIndex):
# we can raise here if we are definitive that this
# is positional indexing (eg. .ix on with a float)
# or label indexing if we are using a type able
# to be represented in the index
if kind in ["getitem", "ix"] and is_float(key):
if not self.is_floating():
return self._invalid_indexer("label", key)
elif kind in ["loc"] and is_float(key):
# we want to raise KeyError on string/mixed here
# technically we *could* raise a TypeError
# on anything but mixed though
if self.inferred_type not in [
"floating",
"mixed-integer-float",
"integer-na",
"string",
"unicode",
"mixed",
]:
self._invalid_indexer("label", key)
elif kind in ["loc"] and is_integer(key):
if not self.holds_integer():
self._invalid_indexer("label", key)
return key
_index_shared_docs[
"_convert_slice_indexer"
] = """
Convert a slice indexer.
By definition, these are labels unless 'iloc' is passed in.
Floats are not allowed as the start, step, or stop of the slice.
Parameters
----------
key : label of the slice bound
kind : {'ix', 'loc', 'getitem', 'iloc'} or None
"""
@Appender(_index_shared_docs["_convert_slice_indexer"])
def _convert_slice_indexer(self, key: slice, kind=None):
assert kind in ["ix", "loc", "getitem", "iloc", None]
# validate iloc
if kind == "iloc":
return slice(
self._validate_indexer("slice", key.start, kind),
self._validate_indexer("slice", key.stop, kind),
self._validate_indexer("slice", key.step, kind),
)
# potentially cast the bounds to integers
start, stop, step = key.start, key.stop, key.step
# figure out if this is a positional indexer
def is_int(v):
return v is None or is_integer(v)
is_null_slicer = start is None and stop is None
is_index_slice = is_int(start) and is_int(stop)
is_positional = is_index_slice and not (
self.is_integer() or self.is_categorical()
)
if kind == "getitem":
"""
called from the getitem slicers, validate that we are in fact
integers
"""
if self.is_integer() or is_index_slice:
return slice(
self._validate_indexer("slice", key.start, kind),
self._validate_indexer("slice", key.stop, kind),
self._validate_indexer("slice", key.step, kind),
)
# convert the slice to an indexer here
# if we are mixed and have integers
try:
if is_positional and self.is_mixed():
# Validate start & stop
if start is not None:
self.get_loc(start)
if stop is not None:
self.get_loc(stop)
is_positional = False
except KeyError:
if self.inferred_type in ["mixed-integer-float", "integer-na"]:
raise
if is_null_slicer:
indexer = key
elif is_positional:
indexer = key
else:
indexer = self.slice_indexer(start, stop, step, kind=kind)
return indexer
def _convert_listlike_indexer(self, keyarr, kind=None):
"""
Parameters
----------
keyarr : list-like
Indexer to convert.
Returns
-------
indexer : numpy.ndarray or None
Return an ndarray or None if cannot convert.
keyarr : numpy.ndarray
Return tuple-safe keys.
"""
if isinstance(keyarr, Index):
keyarr = self._convert_index_indexer(keyarr)
else:
keyarr = self._convert_arr_indexer(keyarr)
indexer = self._convert_list_indexer(keyarr, kind=kind)
return indexer, keyarr
_index_shared_docs[
"_convert_arr_indexer"
] = """
Convert an array-like indexer to the appropriate dtype.
Parameters
----------
keyarr : array-like
Indexer to convert.
Returns
-------
converted_keyarr : array-like
"""
@Appender(_index_shared_docs["_convert_arr_indexer"])
def _convert_arr_indexer(self, keyarr):
keyarr = com.asarray_tuplesafe(keyarr)
return keyarr
_index_shared_docs[
"_convert_index_indexer"
] = """
Convert an Index indexer to the appropriate dtype.
Parameters
----------
keyarr : Index (or sub-class)
Indexer to convert.
Returns
-------
converted_keyarr : Index (or sub-class)
"""
@Appender(_index_shared_docs["_convert_index_indexer"])
def _convert_index_indexer(self, keyarr):
return keyarr
_index_shared_docs[
"_convert_list_indexer"
] = """
Convert a list-like indexer to the appropriate dtype.
Parameters
----------
keyarr : Index (or sub-class)
Indexer to convert.
kind : iloc, ix, loc, optional
Returns
-------
positional indexer or None
"""
@Appender(_index_shared_docs["_convert_list_indexer"])
def _convert_list_indexer(self, keyarr, kind=None):
if (
kind in [None, "iloc", "ix"]
and is_integer_dtype(keyarr)
and not self.is_floating()
and not isinstance(keyarr, ABCPeriodIndex)
):
if self.inferred_type == "mixed-integer":
indexer = self.get_indexer(keyarr)
if (indexer >= 0).all():
return indexer
# missing values are flagged as -1 by get_indexer and negative
# indices are already converted to positive indices in the
# above if-statement, so the negative flags are changed to
# values outside the range of indices so as to trigger an
# IndexError in maybe_convert_indices
indexer[indexer < 0] = len(self)
return maybe_convert_indices(indexer, len(self))
elif not self.inferred_type == "integer":
keyarr = np.where(keyarr < 0, len(self) + keyarr, keyarr)
return keyarr
return None
def _invalid_indexer(self, form, key):
"""
Consistent invalid indexer message.
"""
raise TypeError(
f"cannot do {form} indexing on {type(self)} with these "
f"indexers [{key}] of {type(key)}"
)
# --------------------------------------------------------------------
# Reindex Methods
def _can_reindex(self, indexer):
"""
Check if we are allowing reindexing with this particular indexer.
Parameters
----------
indexer : an integer indexer
Raises
------
ValueError if its a duplicate axis
"""
# trying to reindex on an axis with duplicates
if not self.is_unique and len(indexer):
raise ValueError("cannot reindex from a duplicate axis")
def reindex(self, target, method=None, level=None, limit=None, tolerance=None):
"""
Create index with target's values (move/add/delete values
as necessary).
Parameters
----------
target : an iterable
Returns
-------
new_index : pd.Index
Resulting index.
indexer : np.ndarray or None
Indices of output values in original index.
"""
# GH6552: preserve names when reindexing to non-named target
# (i.e. neither Index nor Series).
preserve_names = not hasattr(target, "name")
# GH7774: preserve dtype/tz if target is empty and not an Index.
target = _ensure_has_len(target) # target may be an iterator
if not isinstance(target, Index) and len(target) == 0:
attrs = self._get_attributes_dict()
attrs.pop("freq", None) # don't preserve freq
values = self._data[:0] # appropriately-dtyped empty array
target = self._simple_new(values, dtype=self.dtype, **attrs)
else:
target = ensure_index(target)
if level is not None:
if method is not None:
raise TypeError("Fill method not supported if level passed")
_, indexer, _ = self._join_level(
target, level, how="right", return_indexers=True
)
else:
if self.equals(target):
indexer = None
else:
# check is_overlapping for IntervalIndex compat
if self.is_unique and not getattr(self, "is_overlapping", False):
indexer = self.get_indexer(
target, method=method, limit=limit, tolerance=tolerance
)
else:
if method is not None or limit is not None:
raise ValueError(
"cannot reindex a non-unique index "
"with a method or limit"
)
indexer, missing = self.get_indexer_non_unique(target)
if preserve_names and target.nlevels == 1 and target.name != self.name:
target = target.copy()
target.name = self.name
return target, indexer
def _reindex_non_unique(self, target):
"""
Create a new index with target's values (move/add/delete values as
necessary) use with non-unique Index and a possibly non-unique target.
Parameters
----------
target : an iterable
Returns
-------
new_index : pd.Index
Resulting index.
indexer : np.ndarray or None
Indices of output values in original index.
"""
target = ensure_index(target)
indexer, missing = self.get_indexer_non_unique(target)
check = indexer != -1
new_labels = self.take(indexer[check])
new_indexer = None
if len(missing):
length = np.arange(len(indexer))
missing = ensure_platform_int(missing)
missing_labels = target.take(missing)
missing_indexer = ensure_int64(length[~check])
cur_labels = self.take(indexer[check]).values
cur_indexer = ensure_int64(length[check])
new_labels = np.empty(tuple([len(indexer)]), dtype=object)
new_labels[cur_indexer] = cur_labels
new_labels[missing_indexer] = missing_labels
# a unique indexer
if target.is_unique:
# see GH5553, make sure we use the right indexer
new_indexer = np.arange(len(indexer))
new_indexer[cur_indexer] = np.arange(len(cur_labels))
new_indexer[missing_indexer] = -1
# we have a non_unique selector, need to use the original
# indexer here
else:
# need to retake to have the same size as the indexer
indexer[~check] = -1
# reset the new indexer to account for the new size
new_indexer = np.arange(len(self.take(indexer)))
new_indexer[~check] = -1
new_index = self._shallow_copy_with_infer(new_labels)
return new_index, indexer, new_indexer
# --------------------------------------------------------------------
# Join Methods
_index_shared_docs[
"join"
] = """
Compute join_index and indexers to conform data
structures to the new index.
Parameters
----------
other : Index
how : {'left', 'right', 'inner', 'outer'}
level : int or level name, default None
return_indexers : bool, default False
sort : bool, default False
Sort the join keys lexicographically in the result Index. If False,
the order of the join keys depends on the join type (how keyword).
Returns
-------
join_index, (left_indexer, right_indexer)
"""
@Appender(_index_shared_docs["join"])
def join(self, other, how="left", level=None, return_indexers=False, sort=False):
self_is_mi = isinstance(self, ABCMultiIndex)
other_is_mi = isinstance(other, ABCMultiIndex)
# try to figure out the join level
# GH3662
if level is None and (self_is_mi or other_is_mi):
# have the same levels/names so a simple join
if self.names == other.names:
pass
else:
return self._join_multi(other, how=how, return_indexers=return_indexers)
# join on the level
if level is not None and (self_is_mi or other_is_mi):
return self._join_level(
other, level, how=how, return_indexers=return_indexers
)
other = ensure_index(other)
if len(other) == 0 and how in ("left", "outer"):
join_index = self._shallow_copy()
if return_indexers:
rindexer = np.repeat(-1, len(join_index))
return join_index, None, rindexer
else:
return join_index
if len(self) == 0 and how in ("right", "outer"):
join_index = other._shallow_copy()
if return_indexers:
lindexer = np.repeat(-1, len(join_index))
return join_index, lindexer, None
else:
return join_index
if self._join_precedence < other._join_precedence:
how = {"right": "left", "left": "right"}.get(how, how)
result = other.join(
self, how=how, level=level, return_indexers=return_indexers
)
if return_indexers:
x, y, z = result
result = x, z, y
return result
if not is_dtype_equal(self.dtype, other.dtype):
this = self.astype("O")
other = other.astype("O")
return this.join(other, how=how, return_indexers=return_indexers)
_validate_join_method(how)
if not self.is_unique and not other.is_unique:
return self._join_non_unique(
other, how=how, return_indexers=return_indexers
)
elif not self.is_unique or not other.is_unique:
if self.is_monotonic and other.is_monotonic:
return self._join_monotonic(
other, how=how, return_indexers=return_indexers
)
else:
return self._join_non_unique(
other, how=how, return_indexers=return_indexers
)
elif self.is_monotonic and other.is_monotonic:
try:
return self._join_monotonic(
other, how=how, return_indexers=return_indexers
)
except TypeError:
pass
if how == "left":
join_index = self
elif how == "right":
join_index = other
elif how == "inner":
# TODO: sort=False here for backwards compat. It may
# be better to use the sort parameter passed into join
join_index = self.intersection(other, sort=False)
elif how == "outer":
# TODO: sort=True here for backwards compat. It may
# be better to use the sort parameter passed into join
join_index = self.union(other)
if sort:
join_index = join_index.sort_values()
if return_indexers:
if join_index is self:
lindexer = None
else:
lindexer = self.get_indexer(join_index)
if join_index is other:
rindexer = None
else:
rindexer = other.get_indexer(join_index)
return join_index, lindexer, rindexer
else:
return join_index
def _join_multi(self, other, how, return_indexers=True):
from .multi import MultiIndex
from pandas.core.reshape.merge import _restore_dropped_levels_multijoin
# figure out join names
self_names = set(com.not_none(*self.names))
other_names = set(com.not_none(*other.names))
overlap = self_names & other_names
# need at least 1 in common
if not overlap:
raise ValueError("cannot join with no overlapping index names")
self_is_mi = isinstance(self, MultiIndex)
other_is_mi = isinstance(other, MultiIndex)
if self_is_mi and other_is_mi:
# Drop the non-matching levels from left and right respectively
ldrop_names = list(self_names - overlap)
rdrop_names = list(other_names - overlap)
# if only the order differs
if not len(ldrop_names + rdrop_names):
self_jnlevels = self
other_jnlevels = other.reorder_levels(self.names)
else:
self_jnlevels = self.droplevel(ldrop_names)
other_jnlevels = other.droplevel(rdrop_names)
# Join left and right
# Join on same leveled multi-index frames is supported
join_idx, lidx, ridx = self_jnlevels.join(
other_jnlevels, how, return_indexers=True
)
# Restore the dropped levels
# Returned index level order is
# common levels, ldrop_names, rdrop_names
dropped_names = ldrop_names + rdrop_names
levels, codes, names = _restore_dropped_levels_multijoin(
self, other, dropped_names, join_idx, lidx, ridx
)
# Re-create the multi-index
multi_join_idx = MultiIndex(
levels=levels, codes=codes, names=names, verify_integrity=False
)
multi_join_idx = multi_join_idx.remove_unused_levels()
return multi_join_idx, lidx, ridx
jl = list(overlap)[0]
# Case where only one index is multi
# make the indices into mi's that match
flip_order = False
if self_is_mi:
self, other = other, self
flip_order = True
# flip if join method is right or left
how = {"right": "left", "left": "right"}.get(how, how)
level = other.names.index(jl)
result = self._join_level(
other, level, how=how, return_indexers=return_indexers
)
if flip_order:
if isinstance(result, tuple):
return result[0], result[2], result[1]
return result
def _join_non_unique(self, other, how="left", return_indexers=False):
from pandas.core.reshape.merge import _get_join_indexers
left_idx, right_idx = _get_join_indexers(
[self._ndarray_values], [other._ndarray_values], how=how, sort=True
)
left_idx = ensure_platform_int(left_idx)
right_idx = ensure_platform_int(right_idx)
join_index = np.asarray(self._ndarray_values.take(left_idx))
mask = left_idx == -1
np.putmask(join_index, mask, other._ndarray_values.take(right_idx))
join_index = self._wrap_joined_index(join_index, other)
if return_indexers:
return join_index, left_idx, right_idx
else:
return join_index
def _join_level(
self, other, level, how="left", return_indexers=False, keep_order=True
):
"""
The join method *only* affects the level of the resulting
MultiIndex. Otherwise it just exactly aligns the Index data to the
labels of the level in the MultiIndex.
If ```keep_order == True```, the order of the data indexed by the
MultiIndex will not be changed; otherwise, it will tie out
with `other`.
"""
from .multi import MultiIndex
def _get_leaf_sorter(labels):
"""
Returns sorter for the inner most level while preserving the
order of higher levels.
"""
if labels[0].size == 0:
return np.empty(0, dtype="int64")
if len(labels) == 1:
lab = ensure_int64(labels[0])
sorter, _ = libalgos.groupsort_indexer(lab, 1 + lab.max())
return sorter
# find indexers of beginning of each set of
# same-key labels w.r.t all but last level
tic = labels[0][:-1] != labels[0][1:]
for lab in labels[1:-1]:
tic |= lab[:-1] != lab[1:]
starts = np.hstack(([True], tic, [True])).nonzero()[0]
lab = ensure_int64(labels[-1])
return lib.get_level_sorter(lab, ensure_int64(starts))
if isinstance(self, MultiIndex) and isinstance(other, MultiIndex):
raise TypeError("Join on level between two MultiIndex objects is ambiguous")
left, right = self, other
flip_order = not isinstance(self, MultiIndex)
if flip_order:
left, right = right, left
how = {"right": "left", "left": "right"}.get(how, how)
level = left._get_level_number(level)
old_level = left.levels[level]
if not right.is_unique:
raise NotImplementedError(
"Index._join_level on non-unique index is not implemented"
)
new_level, left_lev_indexer, right_lev_indexer = old_level.join(
right, how=how, return_indexers=True
)
if left_lev_indexer is None:
if keep_order or len(left) == 0:
left_indexer = None
join_index = left
else: # sort the leaves
left_indexer = _get_leaf_sorter(left.codes[: level + 1])
join_index = left[left_indexer]
else:
left_lev_indexer = ensure_int64(left_lev_indexer)
rev_indexer = lib.get_reverse_indexer(left_lev_indexer, len(old_level))
new_lev_codes = algos.take_nd(
rev_indexer, left.codes[level], allow_fill=False
)
new_codes = list(left.codes)
new_codes[level] = new_lev_codes
new_levels = list(left.levels)
new_levels[level] = new_level
if keep_order: # just drop missing values. o.w. keep order
left_indexer = np.arange(len(left), dtype=np.intp)
mask = new_lev_codes != -1
if not mask.all():
new_codes = [lab[mask] for lab in new_codes]
left_indexer = left_indexer[mask]
else: # tie out the order with other
if level == 0: # outer most level, take the fast route
ngroups = 1 + new_lev_codes.max()
left_indexer, counts = libalgos.groupsort_indexer(
new_lev_codes, ngroups
)
# missing values are placed first; drop them!
left_indexer = left_indexer[counts[0] :]
new_codes = [lab[left_indexer] for lab in new_codes]
else: # sort the leaves
mask = new_lev_codes != -1
mask_all = mask.all()
if not mask_all:
new_codes = [lab[mask] for lab in new_codes]
left_indexer = _get_leaf_sorter(new_codes[: level + 1])
new_codes = [lab[left_indexer] for lab in new_codes]
# left_indexers are w.r.t masked frame.
# reverse to original frame!
if not mask_all:
left_indexer = mask.nonzero()[0][left_indexer]
join_index = MultiIndex(
levels=new_levels,
codes=new_codes,
names=left.names,
verify_integrity=False,
)
if right_lev_indexer is not None:
right_indexer = algos.take_nd(
right_lev_indexer, join_index.codes[level], allow_fill=False
)
else:
right_indexer = join_index.codes[level]
if flip_order:
left_indexer, right_indexer = right_indexer, left_indexer
if return_indexers:
left_indexer = (
None if left_indexer is None else ensure_platform_int(left_indexer)
)
right_indexer = (
None if right_indexer is None else ensure_platform_int(right_indexer)
)
return join_index, left_indexer, right_indexer
else:
return join_index
def _join_monotonic(self, other, how="left", return_indexers=False):
if self.equals(other):
ret_index = other if how == "right" else self
if return_indexers:
return ret_index, None, None
else:
return ret_index
sv = self._ndarray_values
ov = other._ndarray_values
if self.is_unique and other.is_unique:
# We can perform much better than the general case
if how == "left":
join_index = self
lidx = None
ridx = self._left_indexer_unique(sv, ov)
elif how == "right":
join_index = other
lidx = self._left_indexer_unique(ov, sv)
ridx = None
elif how == "inner":
join_index, lidx, ridx = self._inner_indexer(sv, ov)
join_index = self._wrap_joined_index(join_index, other)
elif how == "outer":
join_index, lidx, ridx = self._outer_indexer(sv, ov)
join_index = self._wrap_joined_index(join_index, other)
else:
if how == "left":
join_index, lidx, ridx = self._left_indexer(sv, ov)
elif how == "right":
join_index, ridx, lidx = self._left_indexer(ov, sv)
elif how == "inner":
join_index, lidx, ridx = self._inner_indexer(sv, ov)
elif how == "outer":
join_index, lidx, ridx = self._outer_indexer(sv, ov)
join_index = self._wrap_joined_index(join_index, other)
if return_indexers:
lidx = None if lidx is None else ensure_platform_int(lidx)
ridx = None if ridx is None else ensure_platform_int(ridx)
return join_index, lidx, ridx
else:
return join_index
def _wrap_joined_index(self, joined, other):
name = get_op_result_name(self, other)
return Index(joined, name=name)
# --------------------------------------------------------------------
# Uncategorized Methods
@property
def values(self):
"""
Return an array representing the data in the Index.
.. warning::
We recommend using :attr:`Index.array` or
:meth:`Index.to_numpy`, depending on whether you need
a reference to the underlying data or a NumPy array.
Returns
-------
array: numpy.ndarray or ExtensionArray
See Also
--------
Index.array : Reference to the underlying data.
Index.to_numpy : A NumPy array representing the underlying data.
"""
return self._data.view(np.ndarray)
@property
def _values(self) -> Union[ExtensionArray, ABCIndexClass, np.ndarray]:
# TODO(EA): remove index types as they become extension arrays
"""
The best array representation.
This is an ndarray, ExtensionArray, or Index subclass. This differs
from ``_ndarray_values``, which always returns an ndarray.
Both ``_values`` and ``_ndarray_values`` are consistent between
``Series`` and ``Index``.
It may differ from the public '.values' method.
index | values | _values | _ndarray_values |
----------------- | --------------- | ------------- | --------------- |
Index | ndarray | ndarray | ndarray |
CategoricalIndex | Categorical | Categorical | ndarray[int] |
DatetimeIndex | ndarray[M8ns] | ndarray[M8ns] | ndarray[M8ns] |
DatetimeIndex[tz] | ndarray[M8ns] | DTI[tz] | ndarray[M8ns] |
PeriodIndex | ndarray[object] | PeriodArray | ndarray[int] |
IntervalIndex | IntervalArray | IntervalArray | ndarray[object] |
See Also
--------
values
_ndarray_values
"""
return self._data
def _internal_get_values(self):
"""
Return `Index` data as an `numpy.ndarray`.
Returns
-------
numpy.ndarray
A one-dimensional numpy array of the `Index` values.
See Also
--------
Index.values : The attribute that _internal_get_values wraps.
Examples
--------
Getting the `Index` values of a `DataFrame`:
>>> df = pd.DataFrame([[1, 2, 3], [4, 5, 6], [7, 8, 9]],
... index=['a', 'b', 'c'], columns=['A', 'B', 'C'])
>>> df
A B C
a 1 2 3
b 4 5 6
c 7 8 9
>>> df.index._internal_get_values()
array(['a', 'b', 'c'], dtype=object)
Standalone `Index` values:
>>> idx = pd.Index(['1', '2', '3'])
>>> idx._internal_get_values()
array(['1', '2', '3'], dtype=object)
`MultiIndex` arrays also have only one dimension:
>>> midx = pd.MultiIndex.from_arrays([[1, 2, 3], ['a', 'b', 'c']],
... names=('number', 'letter'))
>>> midx._internal_get_values()
array([(1, 'a'), (2, 'b'), (3, 'c')], dtype=object)
>>> midx._internal_get_values().ndim
1
"""
return self.values
@Appender(IndexOpsMixin.memory_usage.__doc__)
def memory_usage(self, deep=False):
result = super().memory_usage(deep=deep)
# include our engine hashtable
result += self._engine.sizeof(deep=deep)
return result
_index_shared_docs[
"where"
] = """
Return an Index of same shape as self and whose corresponding
entries are from self where cond is True and otherwise are from
other.
Parameters
----------
cond : bool array-like with the same length as self
other : scalar, or array-like
Returns
-------
Index
"""
@Appender(_index_shared_docs["where"])
def where(self, cond, other=None):
if other is None:
other = self._na_value
dtype = self.dtype
values = self.values
if is_bool(other) or is_bool_dtype(other):
# bools force casting
values = values.astype(object)
dtype = None
values = np.where(cond, values, other)
if self._is_numeric_dtype and np.any(isna(values)):
# We can't coerce to the numeric dtype of "self" (unless
# it's float) if there are NaN values in our output.
dtype = None
return self._shallow_copy_with_infer(values, dtype=dtype)
# construction helpers
@classmethod
def _scalar_data_error(cls, data):
# We return the TypeError so that we can raise it from the constructor
# in order to keep mypy happy
return TypeError(
f"{cls.__name__}(...) must be called with a collection of some "
f"kind, {repr(data)} was passed"
)
@classmethod
def _string_data_error(cls, data):
raise TypeError(
"String dtype not supported, you may need "
"to explicitly cast to a numeric type"
)
def _coerce_scalar_to_index(self, item):
"""
We need to coerce a scalar to a compat for our index type.
Parameters
----------
item : scalar item to coerce
"""
dtype = self.dtype
if self._is_numeric_dtype and isna(item):
# We can't coerce to the numeric dtype of "self" (unless
# it's float) if there are NaN values in our output.
dtype = None
return Index([item], dtype=dtype, **self._get_attributes_dict())
def _to_safe_for_reshape(self):
"""
Convert to object if we are a categorical.
"""
return self
def _convert_for_op(self, value):
"""
Convert value to be insertable to ndarray.
"""
return value
def _assert_can_do_op(self, value):
"""
Check value is valid for scalar op.
"""
if not is_scalar(value):
raise TypeError(f"'value' must be a scalar, passed: {type(value).__name__}")
def _is_memory_usage_qualified(self) -> bool:
"""
Return a boolean if we need a qualified .info display.
"""
return self.is_object()
def is_type_compatible(self, kind) -> bool:
"""
Whether the index type is compatible with the provided type.
"""
return kind == self.inferred_type
_index_shared_docs[
"contains"
] = """
Return a boolean indicating whether the provided key is in the index.
Parameters
----------
key : label
The key to check if it is present in the index.
Returns
-------
bool
Whether the key search is in the index.
See Also
--------
Index.isin : Returns an ndarray of boolean dtype indicating whether the
list-like key is in the index.
Examples
--------
>>> idx = pd.Index([1, 2, 3, 4])
>>> idx
Int64Index([1, 2, 3, 4], dtype='int64')
>>> 2 in idx
True
>>> 6 in idx
False
"""
@Appender(_index_shared_docs["contains"] % _index_doc_kwargs)
def __contains__(self, key) -> bool:
hash(key)
try:
return key in self._engine
except (OverflowError, TypeError, ValueError):
return False
def __hash__(self):
raise TypeError(f"unhashable type: {repr(type(self).__name__)}")
def __setitem__(self, key, value):
raise TypeError("Index does not support mutable operations")
def __getitem__(self, key):
"""
Override numpy.ndarray's __getitem__ method to work as desired.
This function adds lists and Series as valid boolean indexers
(ndarrays only supports ndarray with dtype=bool).
If resulting ndim != 1, plain ndarray is returned instead of
corresponding `Index` subclass.
"""
# There's no custom logic to be implemented in __getslice__, so it's
# not overloaded intentionally.
getitem = self._data.__getitem__
promote = self._shallow_copy
if is_scalar(key):
key = com.cast_scalar_indexer(key)
return getitem(key)
if isinstance(key, slice):
# This case is separated from the conditional above to avoid
# pessimization of basic indexing.
return promote(getitem(key))
if com.is_bool_indexer(key):
key = np.asarray(key, dtype=bool)
key = com.values_from_object(key)
result = getitem(key)
if not is_scalar(result):
return promote(result)
else:
return result
def _can_hold_identifiers_and_holds_name(self, name) -> bool:
"""
Faster check for ``name in self`` when we know `name` is a Python
identifier (e.g. in NDFrame.__getattr__, which hits this to support
. key lookup). For indexes that can't hold identifiers (everything
but object & categorical) we just return False.
https://github.com/pandas-dev/pandas/issues/19764
"""
if self.is_object() or self.is_categorical():
return name in self
return False
def append(self, other):
"""
Append a collection of Index options together.
Parameters
----------
other : Index or list/tuple of indices
Returns
-------
appended : Index
"""
to_concat = [self]
if isinstance(other, (list, tuple)):
to_concat = to_concat + list(other)
else:
to_concat.append(other)
for obj in to_concat:
if not isinstance(obj, Index):
raise TypeError("all inputs must be Index")
names = {obj.name for obj in to_concat}
name = None if len(names) > 1 else self.name
return self._concat(to_concat, name)
def _concat(self, to_concat, name):
typs = _concat.get_dtype_kinds(to_concat)
if len(typs) == 1:
return self._concat_same_dtype(to_concat, name=name)
return Index._concat_same_dtype(self, to_concat, name=name)
def _concat_same_dtype(self, to_concat, name):
"""
Concatenate to_concat which has the same class.
"""
# must be overridden in specific classes
klasses = (
ABCDatetimeIndex,
ABCTimedeltaIndex,
ABCPeriodIndex,
ExtensionArray,
ABCIntervalIndex,
)
to_concat = [
x.astype(object) if isinstance(x, klasses) else x for x in to_concat
]
self = to_concat[0]
attribs = self._get_attributes_dict()
attribs["name"] = name
to_concat = [x._values if isinstance(x, Index) else x for x in to_concat]
return self._shallow_copy_with_infer(np.concatenate(to_concat), **attribs)
def putmask(self, mask, value):
"""
Return a new Index of the values set with the mask.
Returns
-------
Index
See Also
--------
numpy.ndarray.putmask
"""
values = self.values.copy()
try:
np.putmask(values, mask, self._convert_for_op(value))
return self._shallow_copy(values)
except (ValueError, TypeError) as err:
if is_object_dtype(self):
raise err
# coerces to object
return self.astype(object).putmask(mask, value)
def equals(self, other) -> bool:
"""
Determine if two Index objects contain the same elements.
Returns
-------
bool
True if "other" is an Index and it has the same elements as calling
index; False otherwise.
"""
if self.is_(other):
return True
if not isinstance(other, Index):
return False
if is_object_dtype(self) and not is_object_dtype(other):
# if other is not object, use other's logic for coercion
return other.equals(self)
if isinstance(other, ABCMultiIndex):
# d-level MultiIndex can equal d-tuple Index
if not is_object_dtype(self.dtype):
if self.nlevels != other.nlevels:
return False
return array_equivalent(
com.values_from_object(self), com.values_from_object(other)
)
def identical(self, other) -> bool:
"""
Similar to equals, but check that other comparable attributes are
also equal.
Returns
-------
bool
If two Index objects have equal elements and same type True,
otherwise False.
"""
return (
self.equals(other)
and all(
(
getattr(self, c, None) == getattr(other, c, None)
for c in self._comparables
)
)
and type(self) == type(other)
)
def asof(self, label):
"""
Return the label from the index, or, if not present, the previous one.
Assuming that the index is sorted, return the passed index label if it
is in the index, or return the previous index label if the passed one
is not in the index.
Parameters
----------
label : object
The label up to which the method returns the latest index label.
Returns
-------
object
The passed label if it is in the index. The previous label if the
passed label is not in the sorted index or `NaN` if there is no
such label.
See Also
--------
Series.asof : Return the latest value in a Series up to the
passed index.
merge_asof : Perform an asof merge (similar to left join but it
matches on nearest key rather than equal key).
Index.get_loc : An `asof` is a thin wrapper around `get_loc`
with method='pad'.
Examples
--------
`Index.asof` returns the latest index label up to the passed label.
>>> idx = pd.Index(['2013-12-31', '2014-01-02', '2014-01-03'])
>>> idx.asof('2014-01-01')
'2013-12-31'
If the label is in the index, the method returns the passed label.
>>> idx.asof('2014-01-02')
'2014-01-02'
If all of the labels in the index are later than the passed label,
NaN is returned.
>>> idx.asof('1999-01-02')
nan
If the index is not sorted, an error is raised.
>>> idx_not_sorted = pd.Index(['2013-12-31', '2015-01-02',
... '2014-01-03'])
>>> idx_not_sorted.asof('2013-12-31')
Traceback (most recent call last):
ValueError: index must be monotonic increasing or decreasing
"""
try:
loc = self.get_loc(label, method="pad")
except KeyError:
return self._na_value
else:
if isinstance(loc, slice):
loc = loc.indices(len(self))[-1]
return self[loc]
def asof_locs(self, where, mask):
"""
Find the locations (indices) of the labels from the index for
every entry in the `where` argument.
As in the `asof` function, if the label (a particular entry in
`where`) is not in the index, the latest index label up to the
passed label is chosen and its index returned.
If all of the labels in the index are later than a label in `where`,
-1 is returned.
`mask` is used to ignore NA values in the index during calculation.
Parameters
----------
where : Index
An Index consisting of an array of timestamps.
mask : array-like
Array of booleans denoting where values in the original
data are not NA.
Returns
-------
numpy.ndarray
An array of locations (indices) of the labels from the Index
which correspond to the return values of the `asof` function
for every element in `where`.
"""
locs = self.values[mask].searchsorted(where.values, side="right")
locs = np.where(locs > 0, locs - 1, 0)
result = np.arange(len(self))[mask].take(locs)
first = mask.argmax()
result[(locs == 0) & (where.values < self.values[first])] = -1
return result
def sort_values(self, return_indexer=False, ascending=True):
"""
Return a sorted copy of the index.
Return a sorted copy of the index, and optionally return the indices
that sorted the index itself.
Parameters
----------
return_indexer : bool, default False
Should the indices that would sort the index be returned.
ascending : bool, default True
Should the index values be sorted in an ascending order.
Returns
-------
sorted_index : pandas.Index
Sorted copy of the index.
indexer : numpy.ndarray, optional
The indices that the index itself was sorted by.
See Also
--------
Series.sort_values : Sort values of a Series.
DataFrame.sort_values : Sort values in a DataFrame.
Examples
--------
>>> idx = pd.Index([10, 100, 1, 1000])
>>> idx
Int64Index([10, 100, 1, 1000], dtype='int64')
Sort values in ascending order (default behavior).
>>> idx.sort_values()
Int64Index([1, 10, 100, 1000], dtype='int64')
Sort values in descending order, and also get the indices `idx` was
sorted by.
>>> idx.sort_values(ascending=False, return_indexer=True)
(Int64Index([1000, 100, 10, 1], dtype='int64'), array([3, 1, 0, 2]))
"""
_as = self.argsort()
if not ascending:
_as = _as[::-1]
sorted_index = self.take(_as)
if return_indexer:
return sorted_index, _as
else:
return sorted_index
def sort(self, *args, **kwargs):
"""
Use sort_values instead.
"""
raise TypeError("cannot sort an Index object in-place, use sort_values instead")
def shift(self, periods=1, freq=None):
"""
Shift index by desired number of time frequency increments.
This method is for shifting the values of datetime-like indexes
by a specified time increment a given number of times.
Parameters
----------
periods : int, default 1
Number of periods (or increments) to shift by,
can be positive or negative.
freq : pandas.DateOffset, pandas.Timedelta or str, optional
Frequency increment to shift by.
If None, the index is shifted by its own `freq` attribute.
Offset aliases are valid strings, e.g., 'D', 'W', 'M' etc.
Returns
-------
pandas.Index
Shifted index.
See Also
--------
Series.shift : Shift values of Series.
Notes
-----
This method is only implemented for datetime-like index classes,
i.e., DatetimeIndex, PeriodIndex and TimedeltaIndex.
Examples
--------
Put the first 5 month starts of 2011 into an index.
>>> month_starts = pd.date_range('1/1/2011', periods=5, freq='MS')
>>> month_starts
DatetimeIndex(['2011-01-01', '2011-02-01', '2011-03-01', '2011-04-01',
'2011-05-01'],
dtype='datetime64[ns]', freq='MS')
Shift the index by 10 days.
>>> month_starts.shift(10, freq='D')
DatetimeIndex(['2011-01-11', '2011-02-11', '2011-03-11', '2011-04-11',
'2011-05-11'],
dtype='datetime64[ns]', freq=None)
The default value of `freq` is the `freq` attribute of the index,
which is 'MS' (month start) in this example.
>>> month_starts.shift(10)
DatetimeIndex(['2011-11-01', '2011-12-01', '2012-01-01', '2012-02-01',
'2012-03-01'],
dtype='datetime64[ns]', freq='MS')
"""
raise NotImplementedError(f"Not supported for type {type(self).__name__}")
def argsort(self, *args, **kwargs):
"""
Return the integer indices that would sort the index.
Parameters
----------
*args
Passed to `numpy.ndarray.argsort`.
**kwargs
Passed to `numpy.ndarray.argsort`.
Returns
-------
numpy.ndarray
Integer indices that would sort the index if used as
an indexer.
See Also
--------
numpy.argsort : Similar method for NumPy arrays.
Index.sort_values : Return sorted copy of Index.
Examples
--------
>>> idx = pd.Index(['b', 'a', 'd', 'c'])
>>> idx
Index(['b', 'a', 'd', 'c'], dtype='object')
>>> order = idx.argsort()
>>> order
array([1, 0, 3, 2])
>>> idx[order]
Index(['a', 'b', 'c', 'd'], dtype='object')
"""
result = self.asi8
if result is None:
result = np.array(self)
return result.argsort(*args, **kwargs)
_index_shared_docs[
"get_value"
] = """
Fast lookup of value from 1-dimensional ndarray. Only use this if you
know what you're doing.
Returns
-------
scalar
A value in the Series with the index of the key value in self.
"""
@Appender(_index_shared_docs["get_value"] % _index_doc_kwargs)
def get_value(self, series, key):
# if we have something that is Index-like, then
# use this, e.g. DatetimeIndex
# Things like `Series._get_value` (via .at) pass the EA directly here.
s = extract_array(series, extract_numpy=True)
if isinstance(s, ExtensionArray):
if is_scalar(key):
# GH 20882, 21257
# First try to convert the key to a location
# If that fails, raise a KeyError if an integer
# index, otherwise, see if key is an integer, and
# try that
try:
iloc = self.get_loc(key)
return s[iloc]
except KeyError:
if len(self) > 0 and (self.holds_integer() or self.is_boolean()):
raise
elif is_integer(key):
return s[key]
else:
# if key is not a scalar, directly raise an error (the code below
# would convert to numpy arrays and raise later any way) - GH29926
raise InvalidIndexError(key)
s = com.values_from_object(series)
k = com.values_from_object(key)
k = self._convert_scalar_indexer(k, kind="getitem")
try:
return self._engine.get_value(s, k, tz=getattr(series.dtype, "tz", None))
except KeyError as e1:
if len(self) > 0 and (self.holds_integer() or self.is_boolean()):
raise
try:
return libindex.get_value_at(s, key)
except IndexError:
raise
except TypeError:
# generator/iterator-like
if is_iterator(key):
raise InvalidIndexError(key)
else:
raise e1
except Exception:
raise e1
except TypeError:
# e.g. "[False] is an invalid key"
if is_scalar(key):
raise IndexError(key)
raise InvalidIndexError(key)
def set_value(self, arr, key, value):
"""
Fast lookup of value from 1-dimensional ndarray.
.. deprecated:: 1.0
Notes
-----
Only use this if you know what you're doing.
"""
warnings.warn(
(
"The 'set_value' method is deprecated, and "
"will be removed in a future version."
),
FutureWarning,
stacklevel=2,
)
self._engine.set_value(
com.values_from_object(arr), com.values_from_object(key), value
)
_index_shared_docs[
"get_indexer_non_unique"
] = """
Compute indexer and mask for new index given the current index. The
indexer should be then used as an input to ndarray.take to align the
current data to the new index.
Parameters
----------
target : %(target_klass)s
Returns
-------
indexer : ndarray of int
Integers from 0 to n - 1 indicating that the index at these
positions matches the corresponding target values. Missing values
in the target are marked by -1.
missing : ndarray of int
An indexer into the target of the values not found.
These correspond to the -1 in the indexer array.
"""
@Appender(_index_shared_docs["get_indexer_non_unique"] % _index_doc_kwargs)
def get_indexer_non_unique(self, target):
target = ensure_index(target)
pself, ptarget = self._maybe_promote(target)
if pself is not self or ptarget is not target:
return pself.get_indexer_non_unique(ptarget)
if is_categorical(target):
tgt_values = np.asarray(target)
elif self.is_all_dates and target.is_all_dates: # GH 30399
tgt_values = target.asi8
else:
tgt_values = target._ndarray_values
indexer, missing = self._engine.get_indexer_non_unique(tgt_values)
return ensure_platform_int(indexer), missing
def get_indexer_for(self, target, **kwargs):
"""
Guaranteed return of an indexer even when non-unique.
This dispatches to get_indexer or get_indexer_non_unique
as appropriate.
Returns
-------
numpy.ndarray
List of indices.
"""
if self.is_unique:
return self.get_indexer(target, **kwargs)
indexer, _ = self.get_indexer_non_unique(target, **kwargs)
return indexer
def _maybe_promote(self, other):
# A hack, but it works
if self.inferred_type == "date" and isinstance(other, ABCDatetimeIndex):
return type(other)(self), other
elif self.inferred_type == "boolean":
if not is_object_dtype(self.dtype):
return self.astype("object"), other.astype("object")
return self, other
def groupby(self, values) -> Dict[Hashable, np.ndarray]:
"""
Group the index labels by a given array of values.
Parameters
----------
values : array
Values used to determine the groups.
Returns
-------
dict
{group name -> group labels}
"""
# TODO: if we are a MultiIndex, we can do better
# that converting to tuples
if isinstance(values, ABCMultiIndex):
values = values.values
values = ensure_categorical(values)
result = values._reverse_indexer()
# map to the label
result = {k: self.take(v) for k, v in result.items()}
return result
def map(self, mapper, na_action=None):
"""
Map values using input correspondence (a dict, Series, or function).
Parameters
----------
mapper : function, dict, or Series
Mapping correspondence.
na_action : {None, 'ignore'}
If 'ignore', propagate NA values, without passing them to the
mapping correspondence.
Returns
-------
applied : Union[Index, MultiIndex], inferred
The output of the mapping function applied to the index.
If the function returns a tuple with more than one element
a MultiIndex will be returned.
"""
from .multi import MultiIndex
new_values = super()._map_values(mapper, na_action=na_action)
attributes = self._get_attributes_dict()
# we can return a MultiIndex
if new_values.size and isinstance(new_values[0], tuple):
if isinstance(self, MultiIndex):
names = self.names
elif attributes.get("name"):
names = [attributes.get("name")] * len(new_values[0])
else:
names = None
return MultiIndex.from_tuples(new_values, names=names)
attributes["copy"] = False
if not new_values.size:
# empty
attributes["dtype"] = self.dtype
return Index(new_values, **attributes)
def isin(self, values, level=None):
"""
Return a boolean array where the index values are in `values`.
Compute boolean array of whether each index value is found in the
passed set of values. The length of the returned boolean array matches
the length of the index.
Parameters
----------
values : set or list-like
Sought values.
level : str or int, optional
Name or position of the index level to use (if the index is a
`MultiIndex`).
Returns
-------
is_contained : ndarray
NumPy array of boolean values.
See Also
--------
Series.isin : Same for Series.
DataFrame.isin : Same method for DataFrames.
Notes
-----
In the case of `MultiIndex` you must either specify `values` as a
list-like object containing tuples that are the same length as the
number of levels, or specify `level`. Otherwise it will raise a
``ValueError``.
If `level` is specified:
- if it is the name of one *and only one* index level, use that level;
- otherwise it should be a number indicating level position.
Examples
--------
>>> idx = pd.Index([1,2,3])
>>> idx
Int64Index([1, 2, 3], dtype='int64')
Check whether each index value in a list of values.
>>> idx.isin([1, 4])
array([ True, False, False])
>>> midx = pd.MultiIndex.from_arrays([[1,2,3],
... ['red', 'blue', 'green']],
... names=('number', 'color'))
>>> midx
MultiIndex(levels=[[1, 2, 3], ['blue', 'green', 'red']],
codes=[[0, 1, 2], [2, 0, 1]],
names=['number', 'color'])
Check whether the strings in the 'color' level of the MultiIndex
are in a list of colors.
>>> midx.isin(['red', 'orange', 'yellow'], level='color')
array([ True, False, False])
To check across the levels of a MultiIndex, pass a list of tuples:
>>> midx.isin([(1, 'red'), (3, 'red')])
array([ True, False, False])
For a DatetimeIndex, string values in `values` are converted to
Timestamps.
>>> dates = ['2000-03-11', '2000-03-12', '2000-03-13']
>>> dti = pd.to_datetime(dates)
>>> dti
DatetimeIndex(['2000-03-11', '2000-03-12', '2000-03-13'],
dtype='datetime64[ns]', freq=None)
>>> dti.isin(['2000-03-11'])
array([ True, False, False])
"""
if level is not None:
self._validate_index_level(level)
return algos.isin(self, values)
def _get_string_slice(self, key, use_lhs=True, use_rhs=True):
# this is for partial string indexing,
# overridden in DatetimeIndex, TimedeltaIndex and PeriodIndex
raise NotImplementedError
def slice_indexer(self, start=None, end=None, step=None, kind=None):
"""
For an ordered or unique index, compute the slice indexer for input
labels and step.
Parameters
----------
start : label, default None
If None, defaults to the beginning.
end : label, default None
If None, defaults to the end.
step : int, default None
kind : str, default None
Returns
-------
indexer : slice
Raises
------
KeyError : If key does not exist, or key is not unique and index is
not ordered.
Notes
-----
This function assumes that the data is sorted, so use at your own peril
Examples
--------
This is a method on all index types. For example you can do:
>>> idx = pd.Index(list('abcd'))
>>> idx.slice_indexer(start='b', end='c')
slice(1, 3)
>>> idx = pd.MultiIndex.from_arrays([list('abcd'), list('efgh')])
>>> idx.slice_indexer(start='b', end=('c', 'g'))
slice(1, 3)
"""
start_slice, end_slice = self.slice_locs(start, end, step=step, kind=kind)
# return a slice
if not is_scalar(start_slice):
raise AssertionError("Start slice bound is non-scalar")
if not is_scalar(end_slice):
raise AssertionError("End slice bound is non-scalar")
return slice(start_slice, end_slice, step)
def _maybe_cast_indexer(self, key):
"""
If we have a float key and are not a floating index, then try to cast
to an int if equivalent.
"""
if is_float(key) and not self.is_floating():
try:
ckey = int(key)
if ckey == key:
key = ckey
except (OverflowError, ValueError, TypeError):
pass
return key
def _validate_indexer(self, form, key, kind):
"""
If we are positional indexer, validate that we have appropriate
typed bounds must be an integer.
"""
assert kind in ["ix", "loc", "getitem", "iloc"]
if key is None:
pass
elif is_integer(key):
pass
elif kind in ["iloc", "getitem"]:
self._invalid_indexer(form, key)
return key
_index_shared_docs[
"_maybe_cast_slice_bound"
] = """
This function should be overloaded in subclasses that allow non-trivial
casting on label-slice bounds, e.g. datetime-like indices allowing
strings containing formatted datetimes.
Parameters
----------
label : object
side : {'left', 'right'}
kind : {'ix', 'loc', 'getitem'}
Returns
-------
label : object
Notes
-----
Value of `side` parameter should be validated in caller.
"""
@Appender(_index_shared_docs["_maybe_cast_slice_bound"])
def _maybe_cast_slice_bound(self, label, side, kind):
assert kind in ["ix", "loc", "getitem", None]
# We are a plain index here (sub-class override this method if they
# wish to have special treatment for floats/ints, e.g. Float64Index and
# datetimelike Indexes
# reject them
if is_float(label):
if not (kind in ["ix"] and (self.holds_integer() or self.is_floating())):
self._invalid_indexer("slice", label)
# we are trying to find integer bounds on a non-integer based index
# this is rejected (generally .loc gets you here)
elif is_integer(label):
self._invalid_indexer("slice", label)
return label
def _searchsorted_monotonic(self, label, side="left"):
if self.is_monotonic_increasing:
return self.searchsorted(label, side=side)
elif self.is_monotonic_decreasing:
# np.searchsorted expects ascending sort order, have to reverse
# everything for it to work (element ordering, search side and
# resulting value).
pos = self[::-1].searchsorted(
label, side="right" if side == "left" else "left"
)
return len(self) - pos
raise ValueError("index must be monotonic increasing or decreasing")
def get_slice_bound(self, label, side, kind):
"""
Calculate slice bound that corresponds to given label.
Returns leftmost (one-past-the-rightmost if ``side=='right'``) position
of given label.
Parameters
----------
label : object
side : {'left', 'right'}
kind : {'ix', 'loc', 'getitem'}
Returns
-------
int
Index of label.
"""
assert kind in ["ix", "loc", "getitem", None]
if side not in ("left", "right"):
raise ValueError(
f"Invalid value for side kwarg, must be either"
f" 'left' or 'right': {side}"
)
original_label = label
# For datetime indices label may be a string that has to be converted
# to datetime boundary according to its resolution.
label = self._maybe_cast_slice_bound(label, side, kind)
# we need to look up the label
try:
slc = self.get_loc(label)
except KeyError as err:
try:
return self._searchsorted_monotonic(label, side)
except ValueError:
# raise the original KeyError
raise err
if isinstance(slc, np.ndarray):
# get_loc may return a boolean array or an array of indices, which
# is OK as long as they are representable by a slice.
if is_bool_dtype(slc):
slc = lib.maybe_booleans_to_slice(slc.view("u1"))
else:
slc = lib.maybe_indices_to_slice(slc.astype("i8"), len(self))
if isinstance(slc, np.ndarray):
raise KeyError(
f"Cannot get {side} slice bound for non-unique "
f"label: {repr(original_label)}"
)
if isinstance(slc, slice):
if side == "left":
return slc.start
else:
return slc.stop
else:
if side == "right":
return slc + 1
else:
return slc
def slice_locs(self, start=None, end=None, step=None, kind=None):
"""
Compute slice locations for input labels.
Parameters
----------
start : label, default None
If None, defaults to the beginning.
end : label, default None
If None, defaults to the end.
step : int, defaults None
If None, defaults to 1.
kind : {'ix', 'loc', 'getitem'} or None
Returns
-------
start, end : int
See Also
--------
Index.get_loc : Get location for a single label.
Notes
-----
This method only works if the index is monotonic or unique.
Examples
--------
>>> idx = pd.Index(list('abcd'))
>>> idx.slice_locs(start='b', end='c')
(1, 3)
"""
inc = step is None or step >= 0
if not inc:
# If it's a reverse slice, temporarily swap bounds.
start, end = end, start
# GH 16785: If start and end happen to be date strings with UTC offsets
# attempt to parse and check that the offsets are the same
if isinstance(start, (str, datetime)) and isinstance(end, (str, datetime)):
try:
ts_start = Timestamp(start)
ts_end = Timestamp(end)
except (ValueError, TypeError):
pass
else:
if not tz_compare(ts_start.tzinfo, ts_end.tzinfo):
raise ValueError("Both dates must have the same UTC offset")
start_slice = None
if start is not None:
start_slice = self.get_slice_bound(start, "left", kind)
if start_slice is None:
start_slice = 0
end_slice = None
if end is not None:
end_slice = self.get_slice_bound(end, "right", kind)
if end_slice is None:
end_slice = len(self)
if not inc:
# Bounds at this moment are swapped, swap them back and shift by 1.
#
# slice_locs('B', 'A', step=-1): s='B', e='A'
#
# s='A' e='B'
# AFTER SWAP: | |
# v ------------------> V
# -----------------------------------
# | | |A|A|A|A| | | | | |B|B| | | | |
# -----------------------------------
# ^ <------------------ ^
# SHOULD BE: | |
# end=s-1 start=e-1
#
end_slice, start_slice = start_slice - 1, end_slice - 1
# i == -1 triggers ``len(self) + i`` selection that points to the
# last element, not before-the-first one, subtracting len(self)
# compensates that.
if end_slice == -1:
end_slice -= len(self)
if start_slice == -1:
start_slice -= len(self)
return start_slice, end_slice
def delete(self, loc):
"""
Make new Index with passed location(-s) deleted.
Returns
-------
new_index : Index
"""
return self._shallow_copy(np.delete(self._data, loc))
def insert(self, loc, item):
"""
Make new Index inserting new item at location.
Follows Python list.append semantics for negative values.
Parameters
----------
loc : int
item : object
Returns
-------
new_index : Index
"""
_self = np.asarray(self)
item = self._coerce_scalar_to_index(item)._ndarray_values
idx = np.concatenate((_self[:loc], item, _self[loc:]))
return self._shallow_copy_with_infer(idx)
def drop(self, labels, errors="raise"):
"""
Make new Index with passed list of labels deleted.
Parameters
----------
labels : array-like
errors : {'ignore', 'raise'}, default 'raise'
If 'ignore', suppress error and existing labels are dropped.
Returns
-------
dropped : Index
Raises
------
KeyError
If not all of the labels are found in the selected axis
"""
arr_dtype = "object" if self.dtype == "object" else None
labels = com.index_labels_to_array(labels, dtype=arr_dtype)
indexer = self.get_indexer(labels)
mask = indexer == -1
if mask.any():
if errors != "ignore":
raise KeyError(f"{labels[mask]} not found in axis")
indexer = indexer[~mask]
return self.delete(indexer)
# --------------------------------------------------------------------
# Generated Arithmetic, Comparison, and Unary Methods
@classmethod
def _add_comparison_methods(cls):
"""
Add in comparison methods.
"""
cls.__eq__ = _make_comparison_op(operator.eq, cls)
cls.__ne__ = _make_comparison_op(operator.ne, cls)
cls.__lt__ = _make_comparison_op(operator.lt, cls)
cls.__gt__ = _make_comparison_op(operator.gt, cls)
cls.__le__ = _make_comparison_op(operator.le, cls)
cls.__ge__ = _make_comparison_op(operator.ge, cls)
@classmethod
def _add_numeric_methods_add_sub_disabled(cls):
"""
Add in the numeric add/sub methods to disable.
"""
cls.__add__ = make_invalid_op("__add__")
cls.__radd__ = make_invalid_op("__radd__")
cls.__iadd__ = make_invalid_op("__iadd__")
cls.__sub__ = make_invalid_op("__sub__")
cls.__rsub__ = make_invalid_op("__rsub__")
cls.__isub__ = make_invalid_op("__isub__")
@classmethod
def _add_numeric_methods_disabled(cls):
"""
Add in numeric methods to disable other than add/sub.
"""
cls.__pow__ = make_invalid_op("__pow__")
cls.__rpow__ = make_invalid_op("__rpow__")
cls.__mul__ = make_invalid_op("__mul__")
cls.__rmul__ = make_invalid_op("__rmul__")
cls.__floordiv__ = make_invalid_op("__floordiv__")
cls.__rfloordiv__ = make_invalid_op("__rfloordiv__")
cls.__truediv__ = make_invalid_op("__truediv__")
cls.__rtruediv__ = make_invalid_op("__rtruediv__")
cls.__mod__ = make_invalid_op("__mod__")
cls.__divmod__ = make_invalid_op("__divmod__")
cls.__neg__ = make_invalid_op("__neg__")
cls.__pos__ = make_invalid_op("__pos__")
cls.__abs__ = make_invalid_op("__abs__")
cls.__inv__ = make_invalid_op("__inv__")
@classmethod
def _add_numeric_methods_binary(cls):
"""
Add in numeric methods.
"""
cls.__add__ = _make_arithmetic_op(operator.add, cls)
cls.__radd__ = _make_arithmetic_op(ops.radd, cls)
cls.__sub__ = _make_arithmetic_op(operator.sub, cls)
cls.__rsub__ = _make_arithmetic_op(ops.rsub, cls)
cls.__rpow__ = _make_arithmetic_op(ops.rpow, cls)
cls.__pow__ = _make_arithmetic_op(operator.pow, cls)
cls.__truediv__ = _make_arithmetic_op(operator.truediv, cls)
cls.__rtruediv__ = _make_arithmetic_op(ops.rtruediv, cls)
# TODO: rmod? rdivmod?
cls.__mod__ = _make_arithmetic_op(operator.mod, cls)
cls.__floordiv__ = _make_arithmetic_op(operator.floordiv, cls)
cls.__rfloordiv__ = _make_arithmetic_op(ops.rfloordiv, cls)
cls.__divmod__ = _make_arithmetic_op(divmod, cls)
cls.__mul__ = _make_arithmetic_op(operator.mul, cls)
cls.__rmul__ = _make_arithmetic_op(ops.rmul, cls)
@classmethod
def _add_numeric_methods_unary(cls):
"""
Add in numeric unary methods.
"""
def _make_evaluate_unary(op, opstr):
def _evaluate_numeric_unary(self):
attrs = self._get_attributes_dict()
return Index(op(self.values), **attrs)
_evaluate_numeric_unary.__name__ = opstr
return _evaluate_numeric_unary
cls.__neg__ = _make_evaluate_unary(operator.neg, "__neg__")
cls.__pos__ = _make_evaluate_unary(operator.pos, "__pos__")
cls.__abs__ = _make_evaluate_unary(np.abs, "__abs__")
cls.__inv__ = _make_evaluate_unary(lambda x: -x, "__inv__")
@classmethod
def _add_numeric_methods(cls):
cls._add_numeric_methods_unary()
cls._add_numeric_methods_binary()
@classmethod
def _add_logical_methods(cls):
"""
Add in logical methods.
"""
_doc = """
%(desc)s
Parameters
----------
*args
These parameters will be passed to numpy.%(outname)s.
**kwargs
These parameters will be passed to numpy.%(outname)s.
Returns
-------
%(outname)s : bool or array_like (if axis is specified)
A single element array_like may be converted to bool."""
_index_shared_docs["index_all"] = dedent(
"""
See Also
--------
Index.any : Return whether any element in an Index is True.
Series.any : Return whether any element in a Series is True.
Series.all : Return whether all elements in a Series are True.
Notes
-----
Not a Number (NaN), positive infinity and negative infinity
evaluate to True because these are not equal to zero.
Examples
--------
**all**
True, because nonzero integers are considered True.
>>> pd.Index([1, 2, 3]).all()
True
False, because ``0`` is considered False.
>>> pd.Index([0, 1, 2]).all()
False
**any**
True, because ``1`` is considered True.
>>> pd.Index([0, 0, 1]).any()
True
False, because ``0`` is considered False.
>>> pd.Index([0, 0, 0]).any()
False
"""
)
_index_shared_docs["index_any"] = dedent(
"""
See Also
--------
Index.all : Return whether all elements are True.
Series.all : Return whether all elements are True.
Notes
-----
Not a Number (NaN), positive infinity and negative infinity
evaluate to True because these are not equal to zero.
Examples
--------
>>> index = pd.Index([0, 1, 2])
>>> index.any()
True
>>> index = pd.Index([0, 0, 0])
>>> index.any()
False
"""
)
def _make_logical_function(name, desc, f):
@Substitution(outname=name, desc=desc)
@Appender(_index_shared_docs["index_" + name])
@Appender(_doc)
def logical_func(self, *args, **kwargs):
result = f(self.values)
if (
isinstance(result, (np.ndarray, ABCSeries, Index))
and result.ndim == 0
):
# return NumPy type
return result.dtype.type(result.item())
else: # pragma: no cover
return result
logical_func.__name__ = name
return logical_func
cls.all = _make_logical_function(
"all", "Return whether all elements are True.", np.all
)
cls.any = _make_logical_function(
"any", "Return whether any element is True.", np.any
)
@classmethod
def _add_logical_methods_disabled(cls):
"""
Add in logical methods to disable.
"""
cls.all = make_invalid_op("all")
cls.any = make_invalid_op("any")
@property
def shape(self):
"""
Return a tuple of the shape of the underlying data.
"""
# not using "(len(self), )" to return "correct" shape if the values
# consists of a >1 D array (see GH-27775)
# overridden in MultiIndex.shape to avoid materializing the values
return self._values.shape
Index._add_numeric_methods_disabled()
Index._add_logical_methods()
Index._add_comparison_methods()
def ensure_index_from_sequences(sequences, names=None):
"""
Construct an index from sequences of data.
A single sequence returns an Index. Many sequences returns a
MultiIndex.
Parameters
----------
sequences : sequence of sequences
names : sequence of str
Returns
-------
index : Index or MultiIndex
Examples
--------
>>> ensure_index_from_sequences([[1, 2, 3]], names=['name'])
Int64Index([1, 2, 3], dtype='int64', name='name')
>>> ensure_index_from_sequences([['a', 'a'], ['a', 'b']],
names=['L1', 'L2'])
MultiIndex([('a', 'a'),
('a', 'b')],
names=['L1', 'L2'])
See Also
--------
ensure_index
"""
from .multi import MultiIndex
if len(sequences) == 1:
if names is not None:
names = names[0]
return Index(sequences[0], name=names)
else:
return MultiIndex.from_arrays(sequences, names=names)
def ensure_index(index_like, copy=False):
"""
Ensure that we have an index from some index-like object.
Parameters
----------
index : sequence
An Index or other sequence
copy : bool
Returns
-------
index : Index or MultiIndex
Examples
--------
>>> ensure_index(['a', 'b'])
Index(['a', 'b'], dtype='object')
>>> ensure_index([('a', 'a'), ('b', 'c')])
Index([('a', 'a'), ('b', 'c')], dtype='object')
>>> ensure_index([['a', 'a'], ['b', 'c']])
MultiIndex([('a', 'b'),
('a', 'c')],
dtype='object')
)
See Also
--------
ensure_index_from_sequences
"""
if isinstance(index_like, Index):
if copy:
index_like = index_like.copy()
return index_like
if hasattr(index_like, "name"):
return Index(index_like, name=index_like.name, copy=copy)
if is_iterator(index_like):
index_like = list(index_like)
# must check for exactly list here because of strict type
# check in clean_index_list
if isinstance(index_like, list):
if type(index_like) != list:
index_like = list(index_like)
converted, all_arrays = lib.clean_index_list(index_like)
if len(converted) > 0 and all_arrays:
from .multi import MultiIndex
return MultiIndex.from_arrays(converted)
else:
index_like = converted
else:
# clean_index_list does the equivalent of copying
# so only need to do this if not list instance
if copy:
from copy import copy
index_like = copy(index_like)
return Index(index_like)
def _ensure_has_len(seq):
"""
If seq is an iterator, put its values into a list.
"""
try:
len(seq)
except TypeError:
return list(seq)
else:
return seq
def _trim_front(strings):
"""
Trims zeros and decimal points.
"""
trimmed = strings
while len(strings) > 0 and all(x[0] == " " for x in trimmed):
trimmed = [x[1:] for x in trimmed]
return trimmed
def _validate_join_method(method):
if method not in ["left", "right", "inner", "outer"]:
raise ValueError(f"do not recognize join method {method}")
def default_index(n):
from pandas.core.indexes.range import RangeIndex
return RangeIndex(0, n, name=None)
def maybe_extract_name(name, obj, cls) -> Optional[Hashable]:
"""
If no name is passed, then extract it from data, validating hashability.
"""
if name is None and isinstance(obj, (Index, ABCSeries)):
# Note we don't just check for "name" attribute since that would
# pick up e.g. dtype.name
name = obj.name
# GH#29069
if not is_hashable(name):
raise TypeError(f"{cls.__name__}.name must be a hashable type")
return name
def _maybe_cast_with_dtype(data: np.ndarray, dtype: np.dtype, copy: bool) -> np.ndarray:
"""
If a dtype is passed, cast to the closest matching dtype that is supported
by Index.
Parameters
----------
data : np.ndarray
dtype : np.dtype
copy : bool
Returns
-------
np.ndarray
"""
# we need to avoid having numpy coerce
# things that look like ints/floats to ints unless
# they are actually ints, e.g. '0' and 0.0
# should not be coerced
# GH 11836
if is_integer_dtype(dtype):
inferred = lib.infer_dtype(data, skipna=False)
if inferred == "integer":
data = maybe_cast_to_integer_array(data, dtype, copy=copy)
elif inferred in ["floating", "mixed-integer-float"]:
if isna(data).any():
raise ValueError("cannot convert float NaN to integer")
if inferred == "mixed-integer-float":
data = maybe_cast_to_integer_array(data, dtype)
# If we are actually all equal to integers,
# then coerce to integer.
try:
data = _try_convert_to_int_array(data, copy, dtype)
except ValueError:
data = np.array(data, dtype=np.float64, copy=copy)
elif inferred == "string":
pass
else:
data = data.astype(dtype)
elif is_float_dtype(dtype):
inferred = lib.infer_dtype(data, skipna=False)
if inferred == "string":
pass
else:
data = data.astype(dtype)
else:
data = np.array(data, dtype=dtype, copy=copy)
return data
def _maybe_cast_data_without_dtype(subarr):
"""
If we have an arraylike input but no passed dtype, try to infer
a supported dtype.
Parameters
----------
subarr : np.ndarray, Index, or Series
Returns
-------
converted : np.ndarray or ExtensionArray
dtype : np.dtype or ExtensionDtype
"""
# Runtime import needed bc IntervalArray imports Index
from pandas.core.arrays import (
IntervalArray,
PeriodArray,
DatetimeArray,
TimedeltaArray,
)
inferred = lib.infer_dtype(subarr, skipna=False)
if inferred == "integer":
try:
data = _try_convert_to_int_array(subarr, False, None)
return data, data.dtype
except ValueError:
pass
return subarr, object
elif inferred in ["floating", "mixed-integer-float", "integer-na"]:
# TODO: Returns IntegerArray for integer-na case in the future
return subarr, np.float64
elif inferred == "interval":
try:
data = IntervalArray._from_sequence(subarr, copy=False)
return data, data.dtype
except ValueError:
# GH27172: mixed closed Intervals --> object dtype
pass
elif inferred == "boolean":
# don't support boolean explicitly ATM
pass
elif inferred != "string":
if inferred.startswith("datetime"):
try:
data = DatetimeArray._from_sequence(subarr, copy=False)
return data, data.dtype
except (ValueError, OutOfBoundsDatetime):
# GH 27011
# If we have mixed timezones, just send it
# down the base constructor
pass
elif inferred.startswith("timedelta"):
data = TimedeltaArray._from_sequence(subarr, copy=False)
return data, data.dtype
elif inferred == "period":
try:
data = PeriodArray._from_sequence(subarr)
return data, data.dtype
except IncompatibleFrequency:
pass
return subarr, subarr.dtype
def _try_convert_to_int_array(
data: np.ndarray, copy: bool, dtype: np.dtype
) -> np.ndarray:
"""
Attempt to convert an array of data into an integer array.
Parameters
----------
data : The data to convert.
copy : bool
Whether to copy the data or not.
dtype : np.dtype
Returns
-------
int_array : data converted to either an ndarray[int64] or ndarray[uint64]
Raises
------
ValueError if the conversion was not successful.
"""
if not is_unsigned_integer_dtype(dtype):
# skip int64 conversion attempt if uint-like dtype is passed, as
# this could return Int64Index when UInt64Index is what's desired
try:
res = data.astype("i8", copy=False)
if (res == data).all():
return res # TODO: might still need to copy
except (OverflowError, TypeError, ValueError):
pass
# Conversion to int64 failed (possibly due to overflow) or was skipped,
# so let's try now with uint64.
try:
res = data.astype("u8", copy=False)
if (res == data).all():
return res # TODO: might still need to copy
except (OverflowError, TypeError, ValueError):
pass
raise ValueError
from datetime import datetime
import operator
from textwrap import dedent
from typing import Dict, FrozenSet, Hashable, Optional, Union
import warnings
import numpy as np
from pandas._libs import algos as libalgos, index as libindex, lib
import pandas._libs.join as libjoin
from pandas._libs.lib import is_datetime_array
from pandas._libs.tslibs import OutOfBoundsDatetime, Timestamp
from pandas._libs.tslibs.period import IncompatibleFrequency
from pandas._libs.tslibs.timezones import tz_compare
from pandas.compat import set_function_name
from pandas.compat.numpy import function as nv
from pandas.util._decorators import Appender, Substitution, cache_readonly
from pandas.core.dtypes import concat as _concat
from pandas.core.dtypes.cast import maybe_cast_to_integer_array
from pandas.core.dtypes.common import (
ensure_categorical,
ensure_int64,
ensure_object,
ensure_platform_int,
is_bool,
is_bool_dtype,
is_categorical,
is_categorical_dtype,
is_datetime64_any_dtype,
is_datetime64tz_dtype,
is_dtype_equal,
is_extension_array_dtype,
is_float,
is_float_dtype,
is_hashable,
is_integer,
is_integer_dtype,
is_interval_dtype,
is_iterator,
is_list_like,
is_object_dtype,
is_period_dtype,
is_scalar,
is_signed_integer_dtype,
is_timedelta64_dtype,
is_unsigned_integer_dtype,
)
from pandas.core.dtypes.concat import concat_compat
from pandas.core.dtypes.generic import (
ABCCategorical,
ABCDataFrame,
ABCDatetimeArray,
ABCDatetimeIndex,
ABCIndexClass,
ABCIntervalIndex,
ABCMultiIndex,
ABCPandasArray,
ABCPeriodIndex,
ABCSeries,
ABCTimedeltaIndex,
)
from pandas.core.dtypes.missing import array_equivalent, isna
from pandas.core import ops
from pandas.core.accessor import CachedAccessor
import pandas.core.algorithms as algos
from pandas.core.arrays import ExtensionArray
from pandas.core.base import IndexOpsMixin, PandasObject
import pandas.core.common as com
from pandas.core.construction import extract_array
from pandas.core.indexers import maybe_convert_indices
from pandas.core.indexes.frozen import FrozenList
import pandas.core.missing as missing
from pandas.core.ops import get_op_result_name
from pandas.core.ops.invalid import make_invalid_op
from pandas.core.strings import StringMethods
from pandas.io.formats.printing import (
default_pprint,
format_object_attrs,
format_object_summary,
pprint_thing,
)
__all__ = ["Index"]
_unsortable_types = frozenset(("mixed", "mixed-integer"))
_index_doc_kwargs = dict(
klass="Index",
inplace="",
target_klass="Index",
raises_section="",
unique="Index",
duplicated="np.ndarray",
)
_index_shared_docs = dict()
def _make_comparison_op(op, cls):
def cmp_method(self, other):
if isinstance(other, (np.ndarray, Index, ABCSeries, ExtensionArray)):
if other.ndim > 0 and len(self) != len(other):
raise ValueError("Lengths must match to compare")
if is_object_dtype(self) and isinstance(other, ABCCategorical):
left = type(other)(self._values, dtype=other.dtype)
return op(left, other)
elif is_object_dtype(self) and not isinstance(self, ABCMultiIndex):
# don't pass MultiIndex
with np.errstate(all="ignore"):
result = ops.comp_method_OBJECT_ARRAY(op, self.values, other)
else:
with np.errstate(all="ignore"):
result = op(self.values, np.asarray(other))
if is_bool_dtype(result):
return result
return ops.invalid_comparison(self, other, op)
name = f"__{op.__name__}__"
return set_function_name(cmp_method, name, cls)
def _make_arithmetic_op(op, cls):
def index_arithmetic_method(self, other):
if isinstance(other, (ABCSeries, ABCDataFrame, ABCTimedeltaIndex)):
return NotImplemented
from pandas import Series
result = op(Series(self), other)
if isinstance(result, tuple):
return (Index(result[0]), Index(result[1]))
return Index(result)
name = f"__{op.__name__}__"
# TODO: docstring?
return set_function_name(index_arithmetic_method, name, cls)
class InvalidIndexError(Exception):
pass
_o_dtype = np.dtype(object)
_Identity = object
def _new_Index(cls, d):
"""
This is called upon unpickling, rather than the default which doesn't
have arguments and breaks __new__.
"""
# required for backward compat, because PI can't be instantiated with
# ordinals through __new__ GH #13277
if issubclass(cls, ABCPeriodIndex):
from pandas.core.indexes.period import _new_PeriodIndex
return _new_PeriodIndex(cls, **d)
if issubclass(cls, ABCMultiIndex):
if "labels" in d and "codes" not in d:
# GH#23752 "labels" kwarg has been replaced with "codes"
d["codes"] = d.pop("labels")
return cls.__new__(cls, **d)
class Index(IndexOpsMixin, PandasObject):
"""
Immutable ndarray implementing an ordered, sliceable set. The basic object
storing axis labels for all pandas objects.
Parameters
----------
data : array-like (1-dimensional)
dtype : NumPy dtype (default: object)
If dtype is None, we find the dtype that best fits the data.
If an actual dtype is provided, we coerce to that dtype if it's safe.
Otherwise, an error will be raised.
copy : bool
Make a copy of input ndarray.
name : object
Name to be stored in the index.
tupleize_cols : bool (default: True)
When True, attempt to create a MultiIndex if possible.
See Also
--------
RangeIndex : Index implementing a monotonic integer range.
CategoricalIndex : Index of :class:`Categorical` s.
MultiIndex : A multi-level, or hierarchical, Index.
IntervalIndex : An Index of :class:`Interval` s.
DatetimeIndex, TimedeltaIndex, PeriodIndex
Int64Index, UInt64Index, Float64Index
Notes
-----
An Index instance can **only** contain hashable objects
Examples
--------
>>> pd.Index([1, 2, 3])
Int64Index([1, 2, 3], dtype='int64')
>>> pd.Index(list('abc'))
Index(['a', 'b', 'c'], dtype='object')
"""
# tolist is not actually deprecated, just suppressed in the __dir__
_deprecations: FrozenSet[str] = (
PandasObject._deprecations
| IndexOpsMixin._deprecations
| frozenset(["contains", "set_value"])
)
# To hand over control to subclasses
_join_precedence = 1
# Cython methods; see github.com/cython/cython/issues/2647
# for why we need to wrap these instead of making them class attributes
# Moreover, cython will choose the appropriate-dtyped sub-function
# given the dtypes of the passed arguments
def _left_indexer_unique(self, left, right):
return libjoin.left_join_indexer_unique(left, right)
def _left_indexer(self, left, right):
return libjoin.left_join_indexer(left, right)
def _inner_indexer(self, left, right):
return libjoin.inner_join_indexer(left, right)
def _outer_indexer(self, left, right):
return libjoin.outer_join_indexer(left, right)
_typ = "index"
_data: Union[ExtensionArray, np.ndarray]
_id = None
_name: Optional[Hashable] = None
# MultiIndex.levels previously allowed setting the index name. We
# don't allow this anymore, and raise if it happens rather than
# failing silently.
_no_setting_name: bool = False
_comparables = ["name"]
_attributes = ["name"]
_is_numeric_dtype = False
_can_hold_na = True
# would we like our indexing holder to defer to us
_defer_to_indexing = False
# prioritize current class for _shallow_copy_with_infer,
# used to infer integers as datetime-likes
_infer_as_myclass = False
_engine_type = libindex.ObjectEngine
# whether we support partial string indexing. Overridden
# in DatetimeIndex and PeriodIndex
_supports_partial_string_indexing = False
_accessors = {"str"}
str = CachedAccessor("str", StringMethods)
# --------------------------------------------------------------------
# Constructors
def __new__(
cls, data=None, dtype=None, copy=False, name=None, tupleize_cols=True, **kwargs,
) -> "Index":
from .range import RangeIndex
from pandas import PeriodIndex, DatetimeIndex, TimedeltaIndex
from .numeric import Float64Index, Int64Index, UInt64Index
from .interval import IntervalIndex
from .category import CategoricalIndex
name = maybe_extract_name(name, data, cls)
if isinstance(data, ABCPandasArray):
# ensure users don't accidentally put a PandasArray in an index.
data = data.to_numpy()
# range
if isinstance(data, RangeIndex):
return RangeIndex(start=data, copy=copy, dtype=dtype, name=name)
elif isinstance(data, range):
return RangeIndex.from_range(data, dtype=dtype, name=name)
# categorical
elif is_categorical_dtype(data) or is_categorical_dtype(dtype):
return CategoricalIndex(data, dtype=dtype, copy=copy, name=name, **kwargs)
# interval
elif is_interval_dtype(data) or is_interval_dtype(dtype):
closed = kwargs.pop("closed", None)
if is_dtype_equal(_o_dtype, dtype):
return IntervalIndex(
data, name=name, copy=copy, closed=closed, **kwargs
).astype(object)
return IntervalIndex(
data, dtype=dtype, name=name, copy=copy, closed=closed, **kwargs
)
elif (
is_datetime64_any_dtype(data)
or is_datetime64_any_dtype(dtype)
or "tz" in kwargs
):
if is_dtype_equal(_o_dtype, dtype):
# GH#23524 passing `dtype=object` to DatetimeIndex is invalid,
# will raise in the where `data` is already tz-aware. So
# we leave it out of this step and cast to object-dtype after
# the DatetimeIndex construction.
# Note we can pass copy=False because the .astype below
# will always make a copy
return DatetimeIndex(data, copy=False, name=name, **kwargs).astype(
object
)
else:
return DatetimeIndex(data, copy=copy, name=name, dtype=dtype, **kwargs)
elif is_timedelta64_dtype(data) or is_timedelta64_dtype(dtype):
if is_dtype_equal(_o_dtype, dtype):
# Note we can pass copy=False because the .astype below
# will always make a copy
return TimedeltaIndex(data, copy=False, name=name, **kwargs).astype(
object
)
else:
return TimedeltaIndex(data, copy=copy, name=name, dtype=dtype, **kwargs)
elif is_period_dtype(data) or is_period_dtype(dtype):
if is_dtype_equal(_o_dtype, dtype):
return PeriodIndex(data, copy=False, name=name, **kwargs).astype(object)
return PeriodIndex(data, dtype=dtype, copy=copy, name=name, **kwargs)
# extension dtype
elif is_extension_array_dtype(data) or is_extension_array_dtype(dtype):
if not (dtype is None or is_object_dtype(dtype)):
# coerce to the provided dtype
ea_cls = dtype.construct_array_type()
data = ea_cls._from_sequence(data, dtype=dtype, copy=False)
else:
data = np.asarray(data, dtype=object)
# coerce to the object dtype
data = data.astype(object)
return Index(data, dtype=object, copy=copy, name=name, **kwargs)
# index-like
elif isinstance(data, (np.ndarray, Index, ABCSeries)):
if dtype is not None:
# we need to avoid having numpy coerce
# things that look like ints/floats to ints unless
# they are actually ints, e.g. '0' and 0.0
# should not be coerced
# GH 11836
data = _maybe_cast_with_dtype(data, dtype, copy)
dtype = data.dtype # TODO: maybe not for object?
# maybe coerce to a sub-class
if is_signed_integer_dtype(data.dtype):
return Int64Index(data, copy=copy, dtype=dtype, name=name)
elif is_unsigned_integer_dtype(data.dtype):
return UInt64Index(data, copy=copy, dtype=dtype, name=name)
elif is_float_dtype(data.dtype):
return Float64Index(data, copy=copy, dtype=dtype, name=name)
elif issubclass(data.dtype.type, np.bool) or is_bool_dtype(data):
subarr = data.astype("object")
else:
subarr = com.asarray_tuplesafe(data, dtype=object)
# asarray_tuplesafe does not always copy underlying data,
# so need to make sure that this happens
if copy:
subarr = subarr.copy()
if dtype is None:
new_data, new_dtype = _maybe_cast_data_without_dtype(subarr)
if new_dtype is not None:
return cls(
new_data, dtype=new_dtype, copy=False, name=name, **kwargs
)
if kwargs:
raise TypeError(f"Unexpected keyword arguments {repr(set(kwargs))}")
return cls._simple_new(subarr, name, **kwargs)
elif hasattr(data, "__array__"):
return Index(np.asarray(data), dtype=dtype, copy=copy, name=name, **kwargs)
elif data is None or is_scalar(data):
raise cls._scalar_data_error(data)
else:
if tupleize_cols and is_list_like(data):
# GH21470: convert iterable to list before determining if empty
if is_iterator(data):
data = list(data)
if data and all(isinstance(e, tuple) for e in data):
# we must be all tuples, otherwise don't construct
# 10697
from .multi import MultiIndex
return MultiIndex.from_tuples(
data, names=name or kwargs.get("names")
)
# other iterable of some kind
subarr = com.asarray_tuplesafe(data, dtype=object)
return Index(subarr, dtype=dtype, copy=copy, name=name, **kwargs)
"""
NOTE for new Index creation:
- _simple_new: It returns new Index with the same type as the caller.
All metadata (such as name) must be provided by caller's responsibility.
Using _shallow_copy is recommended because it fills these metadata
otherwise specified.
- _shallow_copy: It returns new Index with the same type (using
_simple_new), but fills caller's metadata otherwise specified. Passed
kwargs will overwrite corresponding metadata.
- _shallow_copy_with_infer: It returns new Index inferring its type
from passed values. It fills caller's metadata otherwise specified as the
same as _shallow_copy.
See each method's docstring.
"""
@property
def asi8(self):
"""
Integer representation of the values.
Returns
-------
ndarray
An ndarray with int64 dtype.
"""
return None
@classmethod
def _simple_new(cls, values, name=None, dtype=None):
"""
We require that we have a dtype compat for the values. If we are passed
a non-dtype compat, then coerce using the constructor.
Must be careful not to recurse.
"""
if isinstance(values, (ABCSeries, ABCIndexClass)):
# Index._data must always be an ndarray.
# This is no-copy for when _values is an ndarray,
# which should be always at this point.
values = np.asarray(values._values)
result = object.__new__(cls)
result._data = values
# _index_data is a (temporary?) fix to ensure that the direct data
# manipulation we do in `_libs/reduction.pyx` continues to work.
# We need access to the actual ndarray, since we're messing with
# data buffers and strides. We don't re-use `_ndarray_values`, since
# we actually set this value too.
result._index_data = values
result._name = name
return result._reset_identity()
@cache_readonly
def _constructor(self):
return type(self)
# --------------------------------------------------------------------
# Index Internals Methods
def _get_attributes_dict(self):
"""
Return an attributes dict for my class.
"""
return {k: getattr(self, k, None) for k in self._attributes}
_index_shared_docs[
"_shallow_copy"
] = """
Create a new Index with the same class as the caller, don't copy the
data, use the same object attributes with passed in attributes taking
precedence.
*this is an internal non-public method*
Parameters
----------
values : the values to create the new Index, optional
kwargs : updates the default attributes for this Index
"""
@Appender(_index_shared_docs["_shallow_copy"])
def _shallow_copy(self, values=None, **kwargs):
if values is None:
values = self.values
attributes = self._get_attributes_dict()
attributes.update(kwargs)
if not len(values) and "dtype" not in kwargs:
attributes["dtype"] = self.dtype
# _simple_new expects an the type of self._data
values = getattr(values, "_values", values)
if isinstance(values, ABCDatetimeArray):
# `self.values` returns `self` for tz-aware, so we need to unwrap
# more specifically
values = values.asi8
return self._simple_new(values, **attributes)
def _shallow_copy_with_infer(self, values, **kwargs):
"""
Create a new Index inferring the class with passed value, don't copy
the data, use the same object attributes with passed in attributes
taking precedence.
*this is an internal non-public method*
Parameters
----------
values : the values to create the new Index, optional
kwargs : updates the default attributes for this Index
"""
attributes = self._get_attributes_dict()
attributes.update(kwargs)
attributes["copy"] = False
if not len(values) and "dtype" not in kwargs:
attributes["dtype"] = self.dtype
if self._infer_as_myclass:
try:
return self._constructor(values, **attributes)
except (TypeError, ValueError):
pass
return Index(values, **attributes)
def _update_inplace(self, result, **kwargs):
# guard when called from IndexOpsMixin
raise TypeError("Index can't be updated inplace")
def is_(self, other) -> bool:
"""
More flexible, faster check like ``is`` but that works through views.
Note: this is *not* the same as ``Index.identical()``, which checks
that metadata is also the same.
Parameters
----------
other : object
other object to compare against.
Returns
-------
True if both have same underlying data, False otherwise : bool
"""
# use something other than None to be clearer
return self._id is getattr(other, "_id", Ellipsis) and self._id is not None
def _reset_identity(self):
"""
Initializes or resets ``_id`` attribute with new object.
"""
self._id = _Identity()
return self
def _cleanup(self):
self._engine.clear_mapping()
@cache_readonly
def _engine(self):
# property, for now, slow to look up
# to avoid a reference cycle, bind `_ndarray_values` to a local variable, so
# `self` is not passed into the lambda.
_ndarray_values = self._ndarray_values
return self._engine_type(lambda: _ndarray_values, len(self))
# --------------------------------------------------------------------
# Array-Like Methods
# ndarray compat
def __len__(self) -> int:
"""
Return the length of the Index.
"""
return len(self._data)
def __array__(self, dtype=None):
"""
The array interface, return my values.
"""
return np.asarray(self._data, dtype=dtype)
def __array_wrap__(self, result, context=None):
"""
Gets called after a ufunc.
"""
result = lib.item_from_zerodim(result)
if is_bool_dtype(result) or lib.is_scalar(result):
return result
attrs = self._get_attributes_dict()
return Index(result, **attrs)
@cache_readonly
def dtype(self):
"""
Return the dtype object of the underlying data.
"""
return self._data.dtype
def ravel(self, order="C"):
"""
Return an ndarray of the flattened values of the underlying data.
Returns
-------
numpy.ndarray
Flattened array.
See Also
--------
numpy.ndarray.ravel
"""
return self._ndarray_values.ravel(order=order)
def view(self, cls=None):
# we need to see if we are subclassing an
# index type here
if cls is not None and not hasattr(cls, "_typ"):
result = self._data.view(cls)
else:
result = self._shallow_copy()
if isinstance(result, Index):
result._id = self._id
return result
_index_shared_docs[
"astype"
] = """
Create an Index with values cast to dtypes. The class of a new Index
is determined by dtype. When conversion is impossible, a ValueError
exception is raised.
Parameters
----------
dtype : numpy dtype or pandas type
Note that any signed integer `dtype` is treated as ``'int64'``,
and any unsigned integer `dtype` is treated as ``'uint64'``,
regardless of the size.
copy : bool, default True
By default, astype always returns a newly allocated object.
If copy is set to False and internal requirements on dtype are
satisfied, the original data is used to create a new Index
or the original Index is returned.
Returns
-------
Index
Index with values cast to specified dtype.
"""
@Appender(_index_shared_docs["astype"])
def astype(self, dtype, copy=True):
if is_dtype_equal(self.dtype, dtype):
return self.copy() if copy else self
elif is_categorical_dtype(dtype):
from .category import CategoricalIndex
return CategoricalIndex(self.values, name=self.name, dtype=dtype, copy=copy)
elif is_extension_array_dtype(dtype):
return Index(np.asarray(self), dtype=dtype, copy=copy)
try:
return Index(
self.values.astype(dtype, copy=copy), name=self.name, dtype=dtype
)
except (TypeError, ValueError):
raise TypeError(f"Cannot cast {type(self).__name__} to dtype {dtype}")
_index_shared_docs[
"take"
] = """
Return a new %(klass)s of the values selected by the indices.
For internal compatibility with numpy arrays.
Parameters
----------
indices : list
Indices to be taken.
axis : int, optional
The axis over which to select values, always 0.
allow_fill : bool, default True
fill_value : bool, default None
If allow_fill=True and fill_value is not None, indices specified by
-1 is regarded as NA. If Index doesn't hold NA, raise ValueError.
Returns
-------
numpy.ndarray
Elements of given indices.
See Also
--------
numpy.ndarray.take
"""
@Appender(_index_shared_docs["take"] % _index_doc_kwargs)
def take(self, indices, axis=0, allow_fill=True, fill_value=None, **kwargs):
if kwargs:
nv.validate_take(tuple(), kwargs)
indices = ensure_platform_int(indices)
if self._can_hold_na:
taken = self._assert_take_fillable(
self.values,
indices,
allow_fill=allow_fill,
fill_value=fill_value,
na_value=self._na_value,
)
else:
if allow_fill and fill_value is not None:
cls_name = type(self).__name__
raise ValueError(
f"Unable to fill values because {cls_name} cannot contain NA"
)
taken = self.values.take(indices)
return self._shallow_copy(taken)
def _assert_take_fillable(
self, values, indices, allow_fill=True, fill_value=None, na_value=np.nan
):
"""
Internal method to handle NA filling of take.
"""
indices = ensure_platform_int(indices)
# only fill if we are passing a non-None fill_value
if allow_fill and fill_value is not None:
if (indices < -1).any():
raise ValueError(
"When allow_fill=True and fill_value is not None, "
"all indices must be >= -1"
)
taken = algos.take(
values, indices, allow_fill=allow_fill, fill_value=na_value
)
else:
taken = values.take(indices)
return taken
_index_shared_docs[
"repeat"
] = """
Repeat elements of a %(klass)s.
Returns a new %(klass)s where each element of the current %(klass)s
is repeated consecutively a given number of times.
Parameters
----------
repeats : int or array of ints
The number of repetitions for each element. This should be a
non-negative integer. Repeating 0 times will return an empty
%(klass)s.
axis : None
Must be ``None``. Has no effect but is accepted for compatibility
with numpy.
Returns
-------
repeated_index : %(klass)s
Newly created %(klass)s with repeated elements.
See Also
--------
Series.repeat : Equivalent function for Series.
numpy.repeat : Similar method for :class:`numpy.ndarray`.
Examples
--------
>>> idx = pd.Index(['a', 'b', 'c'])
>>> idx
Index(['a', 'b', 'c'], dtype='object')
>>> idx.repeat(2)
Index(['a', 'a', 'b', 'b', 'c', 'c'], dtype='object')
>>> idx.repeat([1, 2, 3])
Index(['a', 'b', 'b', 'c', 'c', 'c'], dtype='object')
"""
@Appender(_index_shared_docs["repeat"] % _index_doc_kwargs)
def repeat(self, repeats, axis=None):
repeats = ensure_platform_int(repeats)
nv.validate_repeat(tuple(), dict(axis=axis))
return self._shallow_copy(self._values.repeat(repeats))
# --------------------------------------------------------------------
# Copying Methods
_index_shared_docs[
"copy"
] = """
Make a copy of this object. Name and dtype sets those attributes on
the new object.
Parameters
----------
name : str, optional
deep : bool, default False
dtype : numpy dtype or pandas type
Returns
-------
copy : Index
Notes
-----
In most cases, there should be no functional difference from using
``deep``, but if ``deep`` is passed it will attempt to deepcopy.
"""
@Appender(_index_shared_docs["copy"])
def copy(self, name=None, deep=False, dtype=None, **kwargs):
if deep:
new_index = self._shallow_copy(self._data.copy())
else:
new_index = self._shallow_copy()
names = kwargs.get("names")
names = self._validate_names(name=name, names=names, deep=deep)
new_index = new_index.set_names(names)
if dtype:
new_index = new_index.astype(dtype)
return new_index
def __copy__(self, **kwargs):
return self.copy(**kwargs)
def __deepcopy__(self, memo=None):
"""
Parameters
----------
memo, default None
Standard signature. Unused
"""
return self.copy(deep=True)
# --------------------------------------------------------------------
# Rendering Methods
def __repr__(self):
"""
Return a string representation for this object.
"""
klass_name = type(self).__name__
data = self._format_data()
attrs = self._format_attrs()
space = self._format_space()
attrs_str = [f"{k}={v}" for k, v in attrs]
prepr = f",{space}".join(attrs_str)
# no data provided, just attributes
if data is None:
data = ""
res = f"{klass_name}({data}{prepr})"
return res
def _format_space(self):
# using space here controls if the attributes
# are line separated or not (the default)
# max_seq_items = get_option('display.max_seq_items')
# if len(self) > max_seq_items:
# space = "\n%s" % (' ' * (len(klass) + 1))
return " "
@property
def _formatter_func(self):
"""
Return the formatter function.
"""
return default_pprint
def _format_data(self, name=None):
"""
Return the formatted data as a unicode string.
"""
# do we want to justify (only do so for non-objects)
is_justify = not (
self.inferred_type in ("string", "unicode")
or (
self.inferred_type == "categorical" and is_object_dtype(self.categories)
)
)
return format_object_summary(
self, self._formatter_func, is_justify=is_justify, name=name
)
def _format_attrs(self):
"""
Return a list of tuples of the (attr,formatted_value).
"""
return format_object_attrs(self)
def _mpl_repr(self):
# how to represent ourselves to matplotlib
return self.values
def format(self, name=False, formatter=None, **kwargs):
"""
Render a string representation of the Index.
"""
header = []
if name:
header.append(
pprint_thing(self.name, escape_chars=("\t", "\r", "\n"))
if self.name is not None
else ""
)
if formatter is not None:
return header + list(self.map(formatter))
return self._format_with_header(header, **kwargs)
def _format_with_header(self, header, na_rep="NaN", **kwargs):
values = self.values
from pandas.io.formats.format import format_array
if is_categorical_dtype(values.dtype):
values = np.array(values)
elif is_object_dtype(values.dtype):
values = lib.maybe_convert_objects(values, safe=1)
if is_object_dtype(values.dtype):
result = [pprint_thing(x, escape_chars=("\t", "\r", "\n")) for x in values]
# could have nans
mask = isna(values)
if mask.any():
result = np.array(result)
result[mask] = na_rep
result = result.tolist()
else:
result = _trim_front(format_array(values, None, justify="left"))
return header + result
def to_native_types(self, slicer=None, **kwargs):
"""
Format specified values of `self` and return them.
Parameters
----------
slicer : int, array-like
An indexer into `self` that specifies which values
are used in the formatting process.
kwargs : dict
Options for specifying how the values should be formatted.
These options include the following:
1) na_rep : str
The value that serves as a placeholder for NULL values
2) quoting : bool or None
Whether or not there are quoted values in `self`
3) date_format : str
The format used to represent date-like values.
Returns
-------
numpy.ndarray
Formatted values.
"""
values = self
if slicer is not None:
values = values[slicer]
return values._format_native_types(**kwargs)
def _format_native_types(self, na_rep="", quoting=None, **kwargs):
"""
Actually format specific types of the index.
"""
mask = isna(self)
if not self.is_object() and not quoting:
values = np.asarray(self).astype(str)
else:
values = np.array(self, dtype=object, copy=True)
values[mask] = na_rep
return values
def _summary(self, name=None):
"""
Return a summarized representation.
Parameters
----------
name : str
name to use in the summary representation
Returns
-------
String with a summarized representation of the index
"""
if len(self) > 0:
head = self[0]
if hasattr(head, "format") and not isinstance(head, str):
head = head.format()
tail = self[-1]
if hasattr(tail, "format") and not isinstance(tail, str):
tail = tail.format()
index_summary = f", {head} to {tail}"
else:
index_summary = ""
if name is None:
name = type(self).__name__
return f"{name}: {len(self)} entries{index_summary}"
# --------------------------------------------------------------------
# Conversion Methods
def to_flat_index(self):
"""
Identity method.
.. versionadded:: 0.24.0
This is implemented for compatibility with subclass implementations
when chaining.
Returns
-------
pd.Index
Caller.
See Also
--------
MultiIndex.to_flat_index : Subclass implementation.
"""
return self
def to_series(self, index=None, name=None):
"""
Create a Series with both index and values equal to the index keys.
Useful with map for returning an indexer based on an index.
Parameters
----------
index : Index, optional
Index of resulting Series. If None, defaults to original index.
name : str, optional
Dame of resulting Series. If None, defaults to name of original
index.
Returns
-------
Series
The dtype will be based on the type of the Index values.
"""
from pandas import Series
if index is None:
index = self._shallow_copy()
if name is None:
name = self.name
return Series(self.values.copy(), index=index, name=name)
def to_frame(self, index=True, name=None):
"""
Create a DataFrame with a column containing the Index.
.. versionadded:: 0.24.0
Parameters
----------
index : bool, default True
Set the index of the returned DataFrame as the original Index.
name : object, default None
The passed name should substitute for the index name (if it has
one).
Returns
-------
DataFrame
DataFrame containing the original Index data.
See Also
--------
Index.to_series : Convert an Index to a Series.
Series.to_frame : Convert Series to DataFrame.
Examples
--------
>>> idx = pd.Index(['Ant', 'Bear', 'Cow'], name='animal')
>>> idx.to_frame()
animal
animal
Ant Ant
Bear Bear
Cow Cow
By default, the original Index is reused. To enforce a new Index:
>>> idx.to_frame(index=False)
animal
0 Ant
1 Bear
2 Cow
To override the name of the resulting column, specify `name`:
>>> idx.to_frame(index=False, name='zoo')
zoo
0 Ant
1 Bear
2 Cow
"""
from pandas import DataFrame
if name is None:
name = self.name or 0
result = DataFrame({name: self._values.copy()})
if index:
result.index = self
return result
# --------------------------------------------------------------------
# Name-Centric Methods
@property
def name(self):
return self._name
@name.setter
def name(self, value):
if self._no_setting_name:
# Used in MultiIndex.levels to avoid silently ignoring name updates.
raise RuntimeError(
"Cannot set name on a level of a MultiIndex. Use "
"'MultiIndex.set_names' instead."
)
maybe_extract_name(value, None, type(self))
self._name = value
def _validate_names(self, name=None, names=None, deep=False):
"""
Handles the quirks of having a singular 'name' parameter for general
Index and plural 'names' parameter for MultiIndex.
"""
from copy import deepcopy
if names is not None and name is not None:
raise TypeError("Can only provide one of `names` and `name`")
elif names is None and name is None:
return deepcopy(self.names) if deep else self.names
elif names is not None:
if not is_list_like(names):
raise TypeError("Must pass list-like as `names`.")
return names
else:
if not is_list_like(name):
return [name]
return name
def _get_names(self):
return FrozenList((self.name,))
def _set_names(self, values, level=None):
"""
Set new names on index. Each name has to be a hashable type.
Parameters
----------
values : str or sequence
name(s) to set
level : int, level name, or sequence of int/level names (default None)
If the index is a MultiIndex (hierarchical), level(s) to set (None
for all levels). Otherwise level must be None
Raises
------
TypeError if each name is not hashable.
"""
if not is_list_like(values):
raise ValueError("Names must be a list-like")
if len(values) != 1:
raise ValueError(f"Length of new names must be 1, got {len(values)}")
# GH 20527
# All items in 'name' need to be hashable:
for name in values:
if not is_hashable(name):
raise TypeError(f"{type(self).__name__}.name must be a hashable type")
self._name = values[0]
names = property(fset=_set_names, fget=_get_names)
def set_names(self, names, level=None, inplace=False):
"""
Set Index or MultiIndex name.
Able to set new names partially and by level.
Parameters
----------
names : label or list of label
Name(s) to set.
level : int, label or list of int or label, optional
If the index is a MultiIndex, level(s) to set (None for all
levels). Otherwise level must be None.
inplace : bool, default False
Modifies the object directly, instead of creating a new Index or
MultiIndex.
Returns
-------
Index
The same type as the caller or None if inplace is True.
See Also
--------
Index.rename : Able to set new names without level.
Examples
--------
>>> idx = pd.Index([1, 2, 3, 4])
>>> idx
Int64Index([1, 2, 3, 4], dtype='int64')
>>> idx.set_names('quarter')
Int64Index([1, 2, 3, 4], dtype='int64', name='quarter')
>>> idx = pd.MultiIndex.from_product([['python', 'cobra'],
... [2018, 2019]])
>>> idx
MultiIndex([('python', 2018),
('python', 2019),
( 'cobra', 2018),
( 'cobra', 2019)],
)
>>> idx.set_names(['kind', 'year'], inplace=True)
>>> idx
MultiIndex([('python', 2018),
('python', 2019),
( 'cobra', 2018),
( 'cobra', 2019)],
names=['kind', 'year'])
>>> idx.set_names('species', level=0)
MultiIndex([('python', 2018),
('python', 2019),
( 'cobra', 2018),
( 'cobra', 2019)],
names=['species', 'year'])
"""
if level is not None and not isinstance(self, ABCMultiIndex):
raise ValueError("Level must be None for non-MultiIndex")
if level is not None and not is_list_like(level) and is_list_like(names):
raise TypeError("Names must be a string when a single level is provided.")
if not is_list_like(names) and level is None and self.nlevels > 1:
raise TypeError("Must pass list-like as `names`.")
if not is_list_like(names):
names = [names]
if level is not None and not is_list_like(level):
level = [level]
if inplace:
idx = self
else:
idx = self._shallow_copy()
idx._set_names(names, level=level)
if not inplace:
return idx
def rename(self, name, inplace=False):
"""
Alter Index or MultiIndex name.
Able to set new names without level. Defaults to returning new index.
Length of names must match number of levels in MultiIndex.
Parameters
----------
name : label or list of labels
Name(s) to set.
inplace : bool, default False
Modifies the object directly, instead of creating a new Index or
MultiIndex.
Returns
-------
Index
The same type as the caller or None if inplace is True.
See Also
--------
Index.set_names : Able to set new names partially and by level.
Examples
--------
>>> idx = pd.Index(['A', 'C', 'A', 'B'], name='score')
>>> idx.rename('grade')
Index(['A', 'C', 'A', 'B'], dtype='object', name='grade')
>>> idx = pd.MultiIndex.from_product([['python', 'cobra'],
... [2018, 2019]],
... names=['kind', 'year'])
>>> idx
MultiIndex([('python', 2018),
('python', 2019),
( 'cobra', 2018),
( 'cobra', 2019)],
names=['kind', 'year'])
>>> idx.rename(['species', 'year'])
MultiIndex([('python', 2018),
('python', 2019),
( 'cobra', 2018),
( 'cobra', 2019)],
names=['species', 'year'])
>>> idx.rename('species')
Traceback (most recent call last):
TypeError: Must pass list-like as `names`.
"""
return self.set_names([name], inplace=inplace)
# --------------------------------------------------------------------
# Level-Centric Methods
@property
def nlevels(self) -> int:
"""
Number of levels.
"""
return 1
def _sort_levels_monotonic(self):
"""
Compat with MultiIndex.
"""
return self
def _validate_index_level(self, level):
"""
Validate index level.
For single-level Index getting level number is a no-op, but some
verification must be done like in MultiIndex.
"""
if isinstance(level, int):
if level < 0 and level != -1:
raise IndexError(
"Too many levels: Index has only 1 level, "
f"{level} is not a valid level number"
)
elif level > 0:
raise IndexError(
f"Too many levels: Index has only 1 level, not {level + 1}"
)
elif level != self.name:
raise KeyError(
f"Requested level ({level}) does not match index name ({self.name})"
)
def _get_level_number(self, level):
self._validate_index_level(level)
return 0
def sortlevel(self, level=None, ascending=True, sort_remaining=None):
"""
For internal compatibility with with the Index API.
Sort the Index. This is for compat with MultiIndex
Parameters
----------
ascending : bool, default True
False to sort in descending order
level, sort_remaining are compat parameters
Returns
-------
Index
"""
return self.sort_values(return_indexer=True, ascending=ascending)
def _get_level_values(self, level):
"""
Return an Index of values for requested level.
This is primarily useful to get an individual level of values from a
MultiIndex, but is provided on Index as well for compatibility.
Parameters
----------
level : int or str
It is either the integer position or the name of the level.
Returns
-------
Index
Calling object, as there is only one level in the Index.
See Also
--------
MultiIndex.get_level_values : Get values for a level of a MultiIndex.
Notes
-----
For Index, level should be 0, since there are no multiple levels.
Examples
--------
>>> idx = pd.Index(list('abc'))
>>> idx
Index(['a', 'b', 'c'], dtype='object')
Get level values by supplying `level` as integer:
>>> idx.get_level_values(0)
Index(['a', 'b', 'c'], dtype='object')
"""
self._validate_index_level(level)
return self
get_level_values = _get_level_values
def droplevel(self, level=0):
"""
Return index with requested level(s) removed.
If resulting index has only 1 level left, the result will be
of Index type, not MultiIndex.
.. versionadded:: 0.23.1 (support for non-MultiIndex)
Parameters
----------
level : int, str, or list-like, default 0
If a string is given, must be the name of a level
If list-like, elements must be names or indexes of levels.
Returns
-------
Index or MultiIndex
"""
if not isinstance(level, (tuple, list)):
level = [level]
levnums = sorted(self._get_level_number(lev) for lev in level)[::-1]
if len(level) == 0:
return self
if len(level) >= self.nlevels:
raise ValueError(
f"Cannot remove {len(level)} levels from an index with {self.nlevels} "
"levels: at least one level must be left."
)
# The two checks above guarantee that here self is a MultiIndex
new_levels = list(self.levels)
new_codes = list(self.codes)
new_names = list(self.names)
for i in levnums:
new_levels.pop(i)
new_codes.pop(i)
new_names.pop(i)
if len(new_levels) == 1:
# set nan if needed
mask = new_codes[0] == -1
result = new_levels[0].take(new_codes[0])
if mask.any():
result = result.putmask(mask, np.nan)
result._name = new_names[0]
return result
else:
from .multi import MultiIndex
return MultiIndex(
levels=new_levels,
codes=new_codes,
names=new_names,
verify_integrity=False,
)
_index_shared_docs[
"_get_grouper_for_level"
] = """
Get index grouper corresponding to an index level
Parameters
----------
mapper: Group mapping function or None
Function mapping index values to groups
level : int or None
Index level
Returns
-------
grouper : Index
Index of values to group on.
labels : ndarray of int or None
Array of locations in level_index.
uniques : Index or None
Index of unique values for level.
"""
@Appender(_index_shared_docs["_get_grouper_for_level"])
def _get_grouper_for_level(self, mapper, level=None):
assert level is None or level == 0
if mapper is None:
grouper = self
else:
grouper = self.map(mapper)
return grouper, None, None
# --------------------------------------------------------------------
# Introspection Methods
@property
def is_monotonic(self) -> bool:
"""
Alias for is_monotonic_increasing.
"""
return self.is_monotonic_increasing
@property
def is_monotonic_increasing(self):
"""
Return if the index is monotonic increasing (only equal or
increasing) values.
Examples
--------
>>> Index([1, 2, 3]).is_monotonic_increasing
True
>>> Index([1, 2, 2]).is_monotonic_increasing
True
>>> Index([1, 3, 2]).is_monotonic_increasing
False
"""
return self._engine.is_monotonic_increasing
@property
def is_monotonic_decreasing(self) -> bool:
"""
Return if the index is monotonic decreasing (only equal or
decreasing) values.
Examples
--------
>>> Index([3, 2, 1]).is_monotonic_decreasing
True
>>> Index([3, 2, 2]).is_monotonic_decreasing
True
>>> Index([3, 1, 2]).is_monotonic_decreasing
False
"""
return self._engine.is_monotonic_decreasing
@property
def _is_strictly_monotonic_increasing(self) -> bool:
"""
Return if the index is strictly monotonic increasing
(only increasing) values.
Examples
--------
>>> Index([1, 2, 3])._is_strictly_monotonic_increasing
True
>>> Index([1, 2, 2])._is_strictly_monotonic_increasing
False
>>> Index([1, 3, 2])._is_strictly_monotonic_increasing
False
"""
return self.is_unique and self.is_monotonic_increasing
@property
def _is_strictly_monotonic_decreasing(self) -> bool:
"""
Return if the index is strictly monotonic decreasing
(only decreasing) values.
Examples
--------
>>> Index([3, 2, 1])._is_strictly_monotonic_decreasing
True
>>> Index([3, 2, 2])._is_strictly_monotonic_decreasing
False
>>> Index([3, 1, 2])._is_strictly_monotonic_decreasing
False
"""
return self.is_unique and self.is_monotonic_decreasing
@cache_readonly
def is_unique(self) -> bool:
"""
Return if the index has unique values.
"""
return self._engine.is_unique
@property
def has_duplicates(self) -> bool:
return not self.is_unique
def is_boolean(self) -> bool:
return self.inferred_type in ["boolean"]
def is_integer(self) -> bool:
return self.inferred_type in ["integer"]
def is_floating(self) -> bool:
return self.inferred_type in ["floating", "mixed-integer-float", "integer-na"]
def is_numeric(self) -> bool:
return self.inferred_type in ["integer", "floating"]
def is_object(self) -> bool:
return is_object_dtype(self.dtype)
def is_categorical(self) -> bool:
"""
Check if the Index holds categorical data.
Returns
-------
boolean
True if the Index is categorical.
See Also
--------
CategoricalIndex : Index for categorical data.
Examples
--------
>>> idx = pd.Index(["Watermelon", "Orange", "Apple",
... "Watermelon"]).astype("category")
>>> idx.is_categorical()
True
>>> idx = pd.Index([1, 3, 5, 7])
>>> idx.is_categorical()
False
>>> s = pd.Series(["Peter", "Victor", "Elisabeth", "Mar"])
>>> s
0 Peter
1 Victor
2 Elisabeth
3 Mar
dtype: object
>>> s.index.is_categorical()
False
"""
return self.inferred_type in ["categorical"]
def is_interval(self) -> bool:
return self.inferred_type in ["interval"]
def is_mixed(self) -> bool:
return self.inferred_type in ["mixed"]
def holds_integer(self):
"""
Whether the type is an integer type.
"""
return self.inferred_type in ["integer", "mixed-integer"]
@cache_readonly
def inferred_type(self):
"""
Return a string of the type inferred from the values.
"""
return lib.infer_dtype(self, skipna=False)
@cache_readonly
def is_all_dates(self) -> bool:
return is_datetime_array(ensure_object(self.values))
# --------------------------------------------------------------------
# Pickle Methods
def __reduce__(self):
d = dict(data=self._data)
d.update(self._get_attributes_dict())
return _new_Index, (type(self), d), None
def __setstate__(self, state):
"""
Necessary for making this object picklable.
"""
if isinstance(state, dict):
self._data = state.pop("data")
for k, v in state.items():
setattr(self, k, v)
elif isinstance(state, tuple):
if len(state) == 2:
nd_state, own_state = state
data = np.empty(nd_state[1], dtype=nd_state[2])
np.ndarray.__setstate__(data, nd_state)
self._name = own_state[0]
else: # pragma: no cover
data = np.empty(state)
np.ndarray.__setstate__(data, state)
self._data = data
self._reset_identity()
else:
raise Exception("invalid pickle state")
_unpickle_compat = __setstate__
# --------------------------------------------------------------------
# Null Handling Methods
_na_value = np.nan
"""The expected NA value to use with this index."""
@cache_readonly
def _isnan(self):
"""
Return if each value is NaN.
"""
if self._can_hold_na:
return isna(self)
else:
# shouldn't reach to this condition by checking hasnans beforehand
values = np.empty(len(self), dtype=np.bool_)
values.fill(False)
return values
@cache_readonly
def _nan_idxs(self):
if self._can_hold_na:
return self._isnan.nonzero()[0]
else:
return np.array([], dtype=np.int64)
@cache_readonly
def hasnans(self):
"""
Return if I have any nans; enables various perf speedups.
"""
if self._can_hold_na:
return bool(self._isnan.any())
else:
return False
def isna(self):
"""
Detect missing values.
Return a boolean same-sized object indicating if the values are NA.
NA values, such as ``None``, :attr:`numpy.NaN` or :attr:`pd.NaT`, get
mapped to ``True`` values.
Everything else get mapped to ``False`` values. Characters such as
empty strings `''` or :attr:`numpy.inf` are not considered NA values
(unless you set ``pandas.options.mode.use_inf_as_na = True``).
Returns
-------
numpy.ndarray
A boolean array of whether my values are NA.
See Also
--------
Index.notna : Boolean inverse of isna.
Index.dropna : Omit entries with missing values.
isna : Top-level isna.
Series.isna : Detect missing values in Series object.
Examples
--------
Show which entries in a pandas.Index are NA. The result is an
array.
>>> idx = pd.Index([5.2, 6.0, np.NaN])
>>> idx
Float64Index([5.2, 6.0, nan], dtype='float64')
>>> idx.isna()
array([False, False, True], dtype=bool)
Empty strings are not considered NA values. None is considered an NA
value.
>>> idx = pd.Index(['black', '', 'red', None])
>>> idx
Index(['black', '', 'red', None], dtype='object')
>>> idx.isna()
array([False, False, False, True], dtype=bool)
For datetimes, `NaT` (Not a Time) is considered as an NA value.
>>> idx = pd.DatetimeIndex([pd.Timestamp('1940-04-25'),
... pd.Timestamp(''), None, pd.NaT])
>>> idx
DatetimeIndex(['1940-04-25', 'NaT', 'NaT', 'NaT'],
dtype='datetime64[ns]', freq=None)
>>> idx.isna()
array([False, True, True, True], dtype=bool)
"""
return self._isnan
isnull = isna
def notna(self):
"""
Detect existing (non-missing) values.
Return a boolean same-sized object indicating if the values are not NA.
Non-missing values get mapped to ``True``. Characters such as empty
strings ``''`` or :attr:`numpy.inf` are not considered NA values
(unless you set ``pandas.options.mode.use_inf_as_na = True``).
NA values, such as None or :attr:`numpy.NaN`, get mapped to ``False``
values.
Returns
-------
numpy.ndarray
Boolean array to indicate which entries are not NA.
See Also
--------
Index.notnull : Alias of notna.
Index.isna: Inverse of notna.
notna : Top-level notna.
Examples
--------
Show which entries in an Index are not NA. The result is an
array.
>>> idx = pd.Index([5.2, 6.0, np.NaN])
>>> idx
Float64Index([5.2, 6.0, nan], dtype='float64')
>>> idx.notna()
array([ True, True, False])
Empty strings are not considered NA values. None is considered a NA
value.
>>> idx = pd.Index(['black', '', 'red', None])
>>> idx
Index(['black', '', 'red', None], dtype='object')
>>> idx.notna()
array([ True, True, True, False])
"""
return ~self.isna()
notnull = notna
_index_shared_docs[
"fillna"
] = """
Fill NA/NaN values with the specified value.
Parameters
----------
value : scalar
Scalar value to use to fill holes (e.g. 0).
This value cannot be a list-likes.
downcast : dict, default is None
a dict of item->dtype of what to downcast if possible,
or the string 'infer' which will try to downcast to an appropriate
equal type (e.g. float64 to int64 if possible).
Returns
-------
filled : Index
"""
@Appender(_index_shared_docs["fillna"])
def fillna(self, value=None, downcast=None):
self._assert_can_do_op(value)
if self.hasnans:
result = self.putmask(self._isnan, value)
if downcast is None:
# no need to care metadata other than name
# because it can't have freq if
return Index(result, name=self.name)
return self._shallow_copy()
_index_shared_docs[
"dropna"
] = """
Return Index without NA/NaN values.
Parameters
----------
how : {'any', 'all'}, default 'any'
If the Index is a MultiIndex, drop the value when any or all levels
are NaN.
Returns
-------
valid : Index
"""
@Appender(_index_shared_docs["dropna"])
def dropna(self, how="any"):
if how not in ("any", "all"):
raise ValueError(f"invalid how option: {how}")
if self.hasnans:
return self._shallow_copy(self.values[~self._isnan])
return self._shallow_copy()
# --------------------------------------------------------------------
# Uniqueness Methods
_index_shared_docs[
"index_unique"
] = """
Return unique values in the index. Uniques are returned in order
of appearance, this does NOT sort.
Parameters
----------
level : int or str, optional, default None
Only return values from specified level (for MultiIndex).
.. versionadded:: 0.23.0
Returns
-------
Index without duplicates
See Also
--------
unique
Series.unique
"""
@Appender(_index_shared_docs["index_unique"] % _index_doc_kwargs)
def unique(self, level=None):
if level is not None:
self._validate_index_level(level)
result = super().unique()
return self._shallow_copy(result)
def drop_duplicates(self, keep="first"):
"""
Return Index with duplicate values removed.
Parameters
----------
keep : {'first', 'last', ``False``}, default 'first'
- 'first' : Drop duplicates except for the first occurrence.
- 'last' : Drop duplicates except for the last occurrence.
- ``False`` : Drop all duplicates.
Returns
-------
deduplicated : Index
See Also
--------
Series.drop_duplicates : Equivalent method on Series.
DataFrame.drop_duplicates : Equivalent method on DataFrame.
Index.duplicated : Related method on Index, indicating duplicate
Index values.
Examples
--------
Generate an pandas.Index with duplicate values.
>>> idx = pd.Index(['lama', 'cow', 'lama', 'beetle', 'lama', 'hippo'])
The `keep` parameter controls which duplicate values are removed.
The value 'first' keeps the first occurrence for each
set of duplicated entries. The default value of keep is 'first'.
>>> idx.drop_duplicates(keep='first')
Index(['lama', 'cow', 'beetle', 'hippo'], dtype='object')
The value 'last' keeps the last occurrence for each set of duplicated
entries.
>>> idx.drop_duplicates(keep='last')
Index(['cow', 'beetle', 'lama', 'hippo'], dtype='object')
The value ``False`` discards all sets of duplicated entries.
>>> idx.drop_duplicates(keep=False)
Index(['cow', 'beetle', 'hippo'], dtype='object')
"""
return super().drop_duplicates(keep=keep)
def duplicated(self, keep="first"):
"""
Indicate duplicate index values.
Duplicated values are indicated as ``True`` values in the resulting
array. Either all duplicates, all except the first, or all except the
last occurrence of duplicates can be indicated.
Parameters
----------
keep : {'first', 'last', False}, default 'first'
The value or values in a set of duplicates to mark as missing.
- 'first' : Mark duplicates as ``True`` except for the first
occurrence.
- 'last' : Mark duplicates as ``True`` except for the last
occurrence.
- ``False`` : Mark all duplicates as ``True``.
Returns
-------
numpy.ndarray
See Also
--------
Series.duplicated : Equivalent method on pandas.Series.
DataFrame.duplicated : Equivalent method on pandas.DataFrame.
Index.drop_duplicates : Remove duplicate values from Index.
Examples
--------
By default, for each set of duplicated values, the first occurrence is
set to False and all others to True:
>>> idx = pd.Index(['lama', 'cow', 'lama', 'beetle', 'lama'])
>>> idx.duplicated()
array([False, False, True, False, True])
which is equivalent to
>>> idx.duplicated(keep='first')
array([False, False, True, False, True])
By using 'last', the last occurrence of each set of duplicated values
is set on False and all others on True:
>>> idx.duplicated(keep='last')
array([ True, False, True, False, False])
By setting keep on ``False``, all duplicates are True:
>>> idx.duplicated(keep=False)
array([ True, False, True, False, True])
"""
return super().duplicated(keep=keep)
def _get_unique_index(self, dropna=False):
"""
Returns an index containing unique values.
Parameters
----------
dropna : bool
If True, NaN values are dropped.
Returns
-------
uniques : index
"""
if self.is_unique and not dropna:
return self
values = self.values
if not self.is_unique:
values = self.unique()
if dropna:
try:
if self.hasnans:
values = values[~isna(values)]
except NotImplementedError:
pass
return self._shallow_copy(values)
# --------------------------------------------------------------------
# Arithmetic & Logical Methods
def __add__(self, other):
if isinstance(other, (ABCSeries, ABCDataFrame)):
return NotImplemented
from pandas import Series
return Index(Series(self) + other)
def __radd__(self, other):
from pandas import Series
return Index(other + Series(self))
def __iadd__(self, other):
# alias for __add__
return self + other
def __sub__(self, other):
return Index(np.array(self) - other)
def __rsub__(self, other):
# wrap Series to ensure we pin name correctly
from pandas import Series
return Index(other - Series(self))
def __and__(self, other):
return self.intersection(other)
def __or__(self, other):
return self.union(other)
def __xor__(self, other):
return self.symmetric_difference(other)
def __nonzero__(self):
raise ValueError(
f"The truth value of a {type(self).__name__} is ambiguous. "
"Use a.empty, a.bool(), a.item(), a.any() or a.all()."
)
__bool__ = __nonzero__
# --------------------------------------------------------------------
# Set Operation Methods
def _get_reconciled_name_object(self, other):
"""
If the result of a set operation will be self,
return self, unless the name changes, in which
case make a shallow copy of self.
"""
name = get_op_result_name(self, other)
if self.name != name:
return self._shallow_copy(name=name)
return self
def _union_incompatible_dtypes(self, other, sort):
"""
Casts this and other index to object dtype to allow the formation
of a union between incompatible types.
Parameters
----------
other : Index or array-like
sort : False or None, default False
Whether to sort the resulting index.
* False : do not sort the result.
* None : sort the result, except when `self` and `other` are equal
or when the values cannot be compared.
Returns
-------
Index
"""
this = self.astype(object, copy=False)
# cast to Index for when `other` is list-like
other = Index(other).astype(object, copy=False)
return Index.union(this, other, sort=sort).astype(object, copy=False)
def _is_compatible_with_other(self, other):
"""
Check whether this and the other dtype are compatible with each other.
Meaning a union can be formed between them without needing to be cast
to dtype object.
Parameters
----------
other : Index or array-like
Returns
-------
bool
"""
return type(self) is type(other) and is_dtype_equal(self.dtype, other.dtype)
def _validate_sort_keyword(self, sort):
if sort not in [None, False]:
raise ValueError(
"The 'sort' keyword only takes the values of "
f"None or False; {sort} was passed."
)
def union(self, other, sort=None):
"""
Form the union of two Index objects.
If the Index objects are incompatible, both Index objects will be
cast to dtype('object') first.
.. versionchanged:: 0.25.0
Parameters
----------
other : Index or array-like
sort : bool or None, default None
Whether to sort the resulting Index.
* None : Sort the result, except when
1. `self` and `other` are equal.
2. `self` or `other` has length 0.
3. Some values in `self` or `other` cannot be compared.
A RuntimeWarning is issued in this case.
* False : do not sort the result.
.. versionadded:: 0.24.0
.. versionchanged:: 0.24.1
Changed the default value from ``True`` to ``None``
(without change in behaviour).
Returns
-------
union : Index
Examples
--------
Union matching dtypes
>>> idx1 = pd.Index([1, 2, 3, 4])
>>> idx2 = pd.Index([3, 4, 5, 6])
>>> idx1.union(idx2)
Int64Index([1, 2, 3, 4, 5, 6], dtype='int64')
Union mismatched dtypes
>>> idx1 = pd.Index(['a', 'b', 'c', 'd'])
>>> idx2 = pd.Index([1, 2, 3, 4])
>>> idx1.union(idx2)
Index(['a', 'b', 'c', 'd', 1, 2, 3, 4], dtype='object')
"""
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
if not self._is_compatible_with_other(other):
return self._union_incompatible_dtypes(other, sort=sort)
return self._union(other, sort=sort)
def _union(self, other, sort):
"""
Specific union logic should go here. In subclasses, union behavior
should be overwritten here rather than in `self.union`.
Parameters
----------
other : Index or array-like
sort : False or None, default False
Whether to sort the resulting index.
* False : do not sort the result.
* None : sort the result, except when `self` and `other` are equal
or when the values cannot be compared.
Returns
-------
Index
"""
if not len(other) or self.equals(other):
return self._get_reconciled_name_object(other)
if not len(self):
return other._get_reconciled_name_object(self)
# TODO(EA): setops-refactor, clean all this up
if is_period_dtype(self) or is_datetime64tz_dtype(self):
lvals = self._ndarray_values
else:
lvals = self._values
if is_period_dtype(other) or is_datetime64tz_dtype(other):
rvals = other._ndarray_values
else:
rvals = other._values
if sort is None and self.is_monotonic and other.is_monotonic:
try:
result = self._outer_indexer(lvals, rvals)[0]
except TypeError:
# incomparable objects
result = list(lvals)
# worth making this faster? a very unusual case
value_set = set(lvals)
result.extend([x for x in rvals if x not in value_set])
else:
# find indexes of things in "other" that are not in "self"
if self.is_unique:
indexer = self.get_indexer(other)
indexer = (indexer == -1).nonzero()[0]
else:
indexer = algos.unique1d(self.get_indexer_non_unique(other)[1])
if len(indexer) > 0:
other_diff = algos.take_nd(rvals, indexer, allow_fill=False)
result = concat_compat((lvals, other_diff))
else:
result = lvals
if sort is None:
try:
result = algos.safe_sort(result)
except TypeError as err:
warnings.warn(
f"{err}, sort order is undefined for incomparable objects",
RuntimeWarning,
stacklevel=3,
)
# for subclasses
return self._wrap_setop_result(other, result)
def _wrap_setop_result(self, other, result):
return self._constructor(result, name=get_op_result_name(self, other))
_index_shared_docs[
"intersection"
] = """
Form the intersection of two Index objects.
This returns a new Index with elements common to the index and `other`.
Parameters
----------
other : Index or array-like
sort : False or None, default False
Whether to sort the resulting index.
* False : do not sort the result.
* None : sort the result, except when `self` and `other` are equal
or when the values cannot be compared.
.. versionadded:: 0.24.0
.. versionchanged:: 0.24.1
Changed the default from ``True`` to ``False``, to match
the behaviour of 0.23.4 and earlier.
Returns
-------
intersection : Index
Examples
--------
>>> idx1 = pd.Index([1, 2, 3, 4])
>>> idx2 = pd.Index([3, 4, 5, 6])
>>> idx1.intersection(idx2)
Int64Index([3, 4], dtype='int64')
"""
# TODO: standardize return type of non-union setops type(self vs other)
@Appender(_index_shared_docs["intersection"])
def intersection(self, other, sort=False):
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
other = ensure_index(other)
if self.equals(other):
return self._get_reconciled_name_object(other)
if not is_dtype_equal(self.dtype, other.dtype):
this = self.astype("O")
other = other.astype("O")
return this.intersection(other, sort=sort)
# TODO(EA): setops-refactor, clean all this up
if is_period_dtype(self):
lvals = self._ndarray_values
else:
lvals = self._values
if is_period_dtype(other):
rvals = other._ndarray_values
else:
rvals = other._values
if self.is_monotonic and other.is_monotonic:
try:
result = self._inner_indexer(lvals, rvals)[0]
return self._wrap_setop_result(other, result)
except TypeError:
pass
try:
indexer = Index(rvals).get_indexer(lvals)
indexer = indexer.take((indexer != -1).nonzero()[0])
except (InvalidIndexError, IncompatibleFrequency):
# InvalidIndexError raised by get_indexer if non-unique
# IncompatibleFrequency raised by PeriodIndex.get_indexer
indexer = algos.unique1d(Index(rvals).get_indexer_non_unique(lvals)[0])
indexer = indexer[indexer != -1]
taken = other.take(indexer)
if sort is None:
taken = algos.safe_sort(taken.values)
if self.name != other.name:
name = None
else:
name = self.name
return self._shallow_copy(taken, name=name)
if self.name != other.name:
taken.name = None
return taken
def difference(self, other, sort=None):
"""
Return a new Index with elements from the index that are not in
`other`.
This is the set difference of two Index objects.
Parameters
----------
other : Index or array-like
sort : False or None, default None
Whether to sort the resulting index. By default, the
values are attempted to be sorted, but any TypeError from
incomparable elements is caught by pandas.
* None : Attempt to sort the result, but catch any TypeErrors
from comparing incomparable elements.
* False : Do not sort the result.
.. versionadded:: 0.24.0
.. versionchanged:: 0.24.1
Changed the default value from ``True`` to ``None``
(without change in behaviour).
Returns
-------
difference : Index
Examples
--------
>>> idx1 = pd.Index([2, 1, 3, 4])
>>> idx2 = pd.Index([3, 4, 5, 6])
>>> idx1.difference(idx2)
Int64Index([1, 2], dtype='int64')
>>> idx1.difference(idx2, sort=False)
Int64Index([2, 1], dtype='int64')
"""
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
if self.equals(other):
# pass an empty np.ndarray with the appropriate dtype
return self._shallow_copy(self._data[:0])
other, result_name = self._convert_can_do_setop(other)
this = self._get_unique_index()
indexer = this.get_indexer(other)
indexer = indexer.take((indexer != -1).nonzero()[0])
label_diff = np.setdiff1d(np.arange(this.size), indexer, assume_unique=True)
the_diff = this.values.take(label_diff)
if sort is None:
try:
the_diff = algos.safe_sort(the_diff)
except TypeError:
pass
return this._shallow_copy(the_diff, name=result_name)
def symmetric_difference(self, other, result_name=None, sort=None):
"""
Compute the symmetric difference of two Index objects.
Parameters
----------
other : Index or array-like
result_name : str
sort : False or None, default None
Whether to sort the resulting index. By default, the
values are attempted to be sorted, but any TypeError from
incomparable elements is caught by pandas.
* None : Attempt to sort the result, but catch any TypeErrors
from comparing incomparable elements.
* False : Do not sort the result.
.. versionadded:: 0.24.0
.. versionchanged:: 0.24.1
Changed the default value from ``True`` to ``None``
(without change in behaviour).
Returns
-------
symmetric_difference : Index
Notes
-----
``symmetric_difference`` contains elements that appear in either
``idx1`` or ``idx2`` but not both. Equivalent to the Index created by
``idx1.difference(idx2) | idx2.difference(idx1)`` with duplicates
dropped.
Examples
--------
>>> idx1 = pd.Index([1, 2, 3, 4])
>>> idx2 = pd.Index([2, 3, 4, 5])
>>> idx1.symmetric_difference(idx2)
Int64Index([1, 5], dtype='int64')
You can also use the ``^`` operator:
>>> idx1 ^ idx2
Int64Index([1, 5], dtype='int64')
"""
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
other, result_name_update = self._convert_can_do_setop(other)
if result_name is None:
result_name = result_name_update
this = self._get_unique_index()
other = other._get_unique_index()
indexer = this.get_indexer(other)
# {this} minus {other}
common_indexer = indexer.take((indexer != -1).nonzero()[0])
left_indexer = np.setdiff1d(
np.arange(this.size), common_indexer, assume_unique=True
)
left_diff = this.values.take(left_indexer)
# {other} minus {this}
right_indexer = (indexer == -1).nonzero()[0]
right_diff = other.values.take(right_indexer)
the_diff = concat_compat([left_diff, right_diff])
if sort is None:
try:
the_diff = algos.safe_sort(the_diff)
except TypeError:
pass
attribs = self._get_attributes_dict()
attribs["name"] = result_name
if "freq" in attribs:
attribs["freq"] = None
return self._shallow_copy_with_infer(the_diff, **attribs)
def _assert_can_do_setop(self, other):
if not is_list_like(other):
raise TypeError("Input must be Index or array-like")
return True
def _convert_can_do_setop(self, other):
if not isinstance(other, Index):
other = Index(other, name=self.name)
result_name = self.name
else:
result_name = get_op_result_name(self, other)
return other, result_name
# --------------------------------------------------------------------
# Indexing Methods
_index_shared_docs[
"get_loc"
] = """
Get integer location, slice or boolean mask for requested label.
Parameters
----------
key : label
method : {None, 'pad'/'ffill', 'backfill'/'bfill', 'nearest'}, optional
* default: exact matches only.
* pad / ffill: find the PREVIOUS index value if no exact match.
* backfill / bfill: use NEXT index value if no exact match
* nearest: use the NEAREST index value if no exact match. Tied
distances are broken by preferring the larger index value.
tolerance : int or float, optional
Maximum distance from index value for inexact matches. The value of
the index at the matching location most satisfy the equation
``abs(index[loc] - key) <= tolerance``.
.. versionadded:: 0.21.0 (list-like tolerance)
Returns
-------
loc : int if unique index, slice if monotonic index, else mask
Examples
--------
>>> unique_index = pd.Index(list('abc'))
>>> unique_index.get_loc('b')
1
>>> monotonic_index = pd.Index(list('abbc'))
>>> monotonic_index.get_loc('b')
slice(1, 3, None)
>>> non_monotonic_index = pd.Index(list('abcb'))
>>> non_monotonic_index.get_loc('b')
array([False, True, False, True], dtype=bool)
"""
@Appender(_index_shared_docs["get_loc"])
def get_loc(self, key, method=None, tolerance=None):
if method is None:
if tolerance is not None:
raise ValueError(
"tolerance argument only valid if using pad, "
"backfill or nearest lookups"
)
try:
return self._engine.get_loc(key)
except KeyError:
return self._engine.get_loc(self._maybe_cast_indexer(key))
indexer = self.get_indexer([key], method=method, tolerance=tolerance)
if indexer.ndim > 1 or indexer.size > 1:
raise TypeError("get_loc requires scalar valued input")
loc = indexer.item()
if loc == -1:
raise KeyError(key)
return loc
_index_shared_docs[
"get_indexer"
] = """
Compute indexer and mask for new index given the current index. The
indexer should be then used as an input to ndarray.take to align the
current data to the new index.
Parameters
----------
target : %(target_klass)s
method : {None, 'pad'/'ffill', 'backfill'/'bfill', 'nearest'}, optional
* default: exact matches only.
* pad / ffill: find the PREVIOUS index value if no exact match.
* backfill / bfill: use NEXT index value if no exact match
* nearest: use the NEAREST index value if no exact match. Tied
distances are broken by preferring the larger index value.
limit : int, optional
Maximum number of consecutive labels in ``target`` to match for
inexact matches.
tolerance : optional
Maximum distance between original and new labels for inexact
matches. The values of the index at the matching locations most
satisfy the equation ``abs(index[indexer] - target) <= tolerance``.
Tolerance may be a scalar value, which applies the same tolerance
to all values, or list-like, which applies variable tolerance per
element. List-like includes list, tuple, array, Series, and must be
the same size as the index and its dtype must exactly match the
index's type.
.. versionadded:: 0.21.0 (list-like tolerance)
Returns
-------
indexer : ndarray of int
Integers from 0 to n - 1 indicating that the index at these
positions matches the corresponding target values. Missing values
in the target are marked by -1.
%(raises_section)s
Examples
--------
>>> index = pd.Index(['c', 'a', 'b'])
>>> index.get_indexer(['a', 'b', 'x'])
array([ 1, 2, -1])
Notice that the return value is an array of locations in ``index``
and ``x`` is marked by -1, as it is not in ``index``.
"""
@Appender(_index_shared_docs["get_indexer"] % _index_doc_kwargs)
def get_indexer(self, target, method=None, limit=None, tolerance=None):
method = missing.clean_reindex_fill_method(method)
target = ensure_index(target)
if tolerance is not None:
tolerance = self._convert_tolerance(tolerance, target)
# Treat boolean labels passed to a numeric index as not found. Without
# this fix False and True would be treated as 0 and 1 respectively.
# (GH #16877)
if target.is_boolean() and self.is_numeric():
return ensure_platform_int(np.repeat(-1, target.size))
pself, ptarget = self._maybe_promote(target)
if pself is not self or ptarget is not target:
return pself.get_indexer(
ptarget, method=method, limit=limit, tolerance=tolerance
)
if not is_dtype_equal(self.dtype, target.dtype):
this = self.astype(object)
target = target.astype(object)
return this.get_indexer(
target, method=method, limit=limit, tolerance=tolerance
)
if not self.is_unique:
raise InvalidIndexError(
"Reindexing only valid with uniquely valued Index objects"
)
if method == "pad" or method == "backfill":
indexer = self._get_fill_indexer(target, method, limit, tolerance)
elif method == "nearest":
indexer = self._get_nearest_indexer(target, limit, tolerance)
else:
if tolerance is not None:
raise ValueError(
"tolerance argument only valid if doing pad, "
"backfill or nearest reindexing"
)
if limit is not None:
raise ValueError(
"limit argument only valid if doing pad, "
"backfill or nearest reindexing"
)
indexer = self._engine.get_indexer(target._ndarray_values)
return ensure_platform_int(indexer)
def _convert_tolerance(self, tolerance, target):
# override this method on subclasses
tolerance = np.asarray(tolerance)
if target.size != tolerance.size and tolerance.size > 1:
raise ValueError("list-like tolerance size must match target index size")
return tolerance
def _get_fill_indexer(self, target, method, limit=None, tolerance=None):
if self.is_monotonic_increasing and target.is_monotonic_increasing:
method = (
self._engine.get_pad_indexer
if method == "pad"
else self._engine.get_backfill_indexer
)
indexer = method(target._ndarray_values, limit)
else:
indexer = self._get_fill_indexer_searchsorted(target, method, limit)
if tolerance is not None:
indexer = self._filter_indexer_tolerance(
target._ndarray_values, indexer, tolerance
)
return indexer
def _get_fill_indexer_searchsorted(self, target, method, limit=None):
"""
Fallback pad/backfill get_indexer that works for monotonic decreasing
indexes and non-monotonic targets.
"""
if limit is not None:
raise ValueError(
f"limit argument for {repr(method)} method only well-defined "
"if index and target are monotonic"
)
side = "left" if method == "pad" else "right"
# find exact matches first (this simplifies the algorithm)
indexer = self.get_indexer(target)
nonexact = indexer == -1
indexer[nonexact] = self._searchsorted_monotonic(target[nonexact], side)
if side == "left":
# searchsorted returns "indices into a sorted array such that,
# if the corresponding elements in v were inserted before the
# indices, the order of a would be preserved".
# Thus, we need to subtract 1 to find values to the left.
indexer[nonexact] -= 1
# This also mapped not found values (values of 0 from
# np.searchsorted) to -1, which conveniently is also our
# sentinel for missing values
else:
# Mark indices to the right of the largest value as not found
indexer[indexer == len(self)] = -1
return indexer
def _get_nearest_indexer(self, target, limit, tolerance):
"""
Get the indexer for the nearest index labels; requires an index with
values that can be subtracted from each other (e.g., not strings or
tuples).
"""
left_indexer = self.get_indexer(target, "pad", limit=limit)
right_indexer = self.get_indexer(target, "backfill", limit=limit)
target = np.asarray(target)
left_distances = abs(self.values[left_indexer] - target)
right_distances = abs(self.values[right_indexer] - target)
op = operator.lt if self.is_monotonic_increasing else operator.le
indexer = np.where(
op(left_distances, right_distances) | (right_indexer == -1),
left_indexer,
right_indexer,
)
if tolerance is not None:
indexer = self._filter_indexer_tolerance(target, indexer, tolerance)
return indexer
def _filter_indexer_tolerance(self, target, indexer, tolerance):
distance = abs(self.values[indexer] - target)
indexer = np.where(distance <= tolerance, indexer, -1)
return indexer
# --------------------------------------------------------------------
# Indexer Conversion Methods
_index_shared_docs[
"_convert_scalar_indexer"
] = """
Convert a scalar indexer.
Parameters
----------
key : label of the slice bound
kind : {'ix', 'loc', 'getitem', 'iloc'} or None
"""
@Appender(_index_shared_docs["_convert_scalar_indexer"])
def _convert_scalar_indexer(self, key, kind=None):
assert kind in ["ix", "loc", "getitem", "iloc", None]
if kind == "iloc":
return self._validate_indexer("positional", key, kind)
if len(self) and not isinstance(self, ABCMultiIndex):
# we can raise here if we are definitive that this
# is positional indexing (eg. .ix on with a float)
# or label indexing if we are using a type able
# to be represented in the index
if kind in ["getitem", "ix"] and is_float(key):
if not self.is_floating():
return self._invalid_indexer("label", key)
elif kind in ["loc"] and is_float(key):
# we want to raise KeyError on string/mixed here
# technically we *could* raise a TypeError
# on anything but mixed though
if self.inferred_type not in [
"floating",
"mixed-integer-float",
"integer-na",
"string",
"unicode",
"mixed",
]:
self._invalid_indexer("label", key)
elif kind in ["loc"] and is_integer(key):
if not self.holds_integer():
self._invalid_indexer("label", key)
return key
_index_shared_docs[
"_convert_slice_indexer"
] = """
Convert a slice indexer.
By definition, these are labels unless 'iloc' is passed in.
Floats are not allowed as the start, step, or stop of the slice.
Parameters
----------
key : label of the slice bound
kind : {'ix', 'loc', 'getitem', 'iloc'} or None
"""
@Appender(_index_shared_docs["_convert_slice_indexer"])
def _convert_slice_indexer(self, key: slice, kind=None):
assert kind in ["ix", "loc", "getitem", "iloc", None]
# validate iloc
if kind == "iloc":
return slice(
self._validate_indexer("slice", key.start, kind),
self._validate_indexer("slice", key.stop, kind),
self._validate_indexer("slice", key.step, kind),
)
# potentially cast the bounds to integers
start, stop, step = key.start, key.stop, key.step
# figure out if this is a positional indexer
def is_int(v):
return v is None or is_integer(v)
is_null_slicer = start is None and stop is None
is_index_slice = is_int(start) and is_int(stop)
is_positional = is_index_slice and not (
self.is_integer() or self.is_categorical()
)
if kind == "getitem":
"""
called from the getitem slicers, validate that we are in fact
integers
"""
if self.is_integer() or is_index_slice:
return slice(
self._validate_indexer("slice", key.start, kind),
self._validate_indexer("slice", key.stop, kind),
self._validate_indexer("slice", key.step, kind),
)
# convert the slice to an indexer here
# if we are mixed and have integers
try:
if is_positional and self.is_mixed():
# Validate start & stop
if start is not None:
self.get_loc(start)
if stop is not None:
self.get_loc(stop)
is_positional = False
except KeyError:
if self.inferred_type in ["mixed-integer-float", "integer-na"]:
raise
if is_null_slicer:
indexer = key
elif is_positional:
indexer = key
else:
indexer = self.slice_indexer(start, stop, step, kind=kind)
return indexer
def _convert_listlike_indexer(self, keyarr, kind=None):
"""
Parameters
----------
keyarr : list-like
Indexer to convert.
Returns
-------
indexer : numpy.ndarray or None
Return an ndarray or None if cannot convert.
keyarr : numpy.ndarray
Return tuple-safe keys.
"""
if isinstance(keyarr, Index):
keyarr = self._convert_index_indexer(keyarr)
else:
keyarr = self._convert_arr_indexer(keyarr)
indexer = self._convert_list_indexer(keyarr, kind=kind)
return indexer, keyarr
_index_shared_docs[
"_convert_arr_indexer"
] = """
Convert an array-like indexer to the appropriate dtype.
Parameters
----------
keyarr : array-like
Indexer to convert.
Returns
-------
converted_keyarr : array-like
"""
@Appender(_index_shared_docs["_convert_arr_indexer"])
def _convert_arr_indexer(self, keyarr):
keyarr = com.asarray_tuplesafe(keyarr)
return keyarr
_index_shared_docs[
"_convert_index_indexer"
] = """
Convert an Index indexer to the appropriate dtype.
Parameters
----------
keyarr : Index (or sub-class)
Indexer to convert.
Returns
-------
converted_keyarr : Index (or sub-class)
"""
@Appender(_index_shared_docs["_convert_index_indexer"])
def _convert_index_indexer(self, keyarr):
return keyarr
_index_shared_docs[
"_convert_list_indexer"
] = """
Convert a list-like indexer to the appropriate dtype.
Parameters
----------
keyarr : Index (or sub-class)
Indexer to convert.
kind : iloc, ix, loc, optional
Returns
-------
positional indexer or None
"""
@Appender(_index_shared_docs["_convert_list_indexer"])
def _convert_list_indexer(self, keyarr, kind=None):
if (
kind in [None, "iloc", "ix"]
and is_integer_dtype(keyarr)
and not self.is_floating()
and not isinstance(keyarr, ABCPeriodIndex)
):
if self.inferred_type == "mixed-integer":
indexer = self.get_indexer(keyarr)
if (indexer >= 0).all():
return indexer
# missing values are flagged as -1 by get_indexer and negative
# indices are already converted to positive indices in the
# above if-statement, so the negative flags are changed to
# values outside the range of indices so as to trigger an
# IndexError in maybe_convert_indices
indexer[indexer < 0] = len(self)
return maybe_convert_indices(indexer, len(self))
elif not self.inferred_type == "integer":
keyarr = np.where(keyarr < 0, len(self) + keyarr, keyarr)
return keyarr
return None
def _invalid_indexer(self, form, key):
"""
Consistent invalid indexer message.
"""
raise TypeError(
f"cannot do {form} indexing on {type(self)} with these "
f"indexers [{key}] of {type(key)}"
)
# --------------------------------------------------------------------
# Reindex Methods
def _can_reindex(self, indexer):
"""
Check if we are allowing reindexing with this particular indexer.
Parameters
----------
indexer : an integer indexer
Raises
------
ValueError if its a duplicate axis
"""
# trying to reindex on an axis with duplicates
if not self.is_unique and len(indexer):
raise ValueError("cannot reindex from a duplicate axis")
def reindex(self, target, method=None, level=None, limit=None, tolerance=None):
"""
Create index with target's values (move/add/delete values
as necessary).
Parameters
----------
target : an iterable
Returns
-------
new_index : pd.Index
Resulting index.
indexer : np.ndarray or None
Indices of output values in original index.
"""
# GH6552: preserve names when reindexing to non-named target
# (i.e. neither Index nor Series).
preserve_names = not hasattr(target, "name")
# GH7774: preserve dtype/tz if target is empty and not an Index.
target = _ensure_has_len(target) # target may be an iterator
if not isinstance(target, Index) and len(target) == 0:
attrs = self._get_attributes_dict()
attrs.pop("freq", None) # don't preserve freq
values = self._data[:0] # appropriately-dtyped empty array
target = self._simple_new(values, dtype=self.dtype, **attrs)
else:
target = ensure_index(target)
if level is not None:
if method is not None:
raise TypeError("Fill method not supported if level passed")
_, indexer, _ = self._join_level(
target, level, how="right", return_indexers=True
)
else:
if self.equals(target):
indexer = None
else:
# check is_overlapping for IntervalIndex compat
if self.is_unique and not getattr(self, "is_overlapping", False):
indexer = self.get_indexer(
target, method=method, limit=limit, tolerance=tolerance
)
else:
if method is not None or limit is not None:
raise ValueError(
"cannot reindex a non-unique index "
"with a method or limit"
)
indexer, missing = self.get_indexer_non_unique(target)
if preserve_names and target.nlevels == 1 and target.name != self.name:
target = target.copy()
target.name = self.name
return target, indexer
def _reindex_non_unique(self, target):
"""
Create a new index with target's values (move/add/delete values as
necessary) use with non-unique Index and a possibly non-unique target.
Parameters
----------
target : an iterable
Returns
-------
new_index : pd.Index
Resulting index.
indexer : np.ndarray or None
Indices of output values in original index.
"""
target = ensure_index(target)
indexer, missing = self.get_indexer_non_unique(target)
check = indexer != -1
new_labels = self.take(indexer[check])
new_indexer = None
if len(missing):
length = np.arange(len(indexer))
missing = ensure_platform_int(missing)
missing_labels = target.take(missing)
missing_indexer = ensure_int64(length[~check])
cur_labels = self.take(indexer[check]).values
cur_indexer = ensure_int64(length[check])
new_labels = np.empty(tuple([len(indexer)]), dtype=object)
new_labels[cur_indexer] = cur_labels
new_labels[missing_indexer] = missing_labels
# a unique indexer
if target.is_unique:
# see GH5553, make sure we use the right indexer
new_indexer = np.arange(len(indexer))
new_indexer[cur_indexer] = np.arange(len(cur_labels))
new_indexer[missing_indexer] = -1
# we have a non_unique selector, need to use the original
# indexer here
else:
# need to retake to have the same size as the indexer
indexer[~check] = -1
# reset the new indexer to account for the new size
new_indexer = np.arange(len(self.take(indexer)))
new_indexer[~check] = -1
new_index = self._shallow_copy_with_infer(new_labels)
return new_index, indexer, new_indexer
# --------------------------------------------------------------------
# Join Methods
_index_shared_docs[
"join"
] = """
Compute join_index and indexers to conform data
structures to the new index.
Parameters
----------
other : Index
how : {'left', 'right', 'inner', 'outer'}
level : int or level name, default None
return_indexers : bool, default False
sort : bool, default False
Sort the join keys lexicographically in the result Index. If False,
the order of the join keys depends on the join type (how keyword).
Returns
-------
join_index, (left_indexer, right_indexer)
"""
@Appender(_index_shared_docs["join"])
def join(self, other, how="left", level=None, return_indexers=False, sort=False):
self_is_mi = isinstance(self, ABCMultiIndex)
other_is_mi = isinstance(other, ABCMultiIndex)
# try to figure out the join level
# GH3662
if level is None and (self_is_mi or other_is_mi):
# have the same levels/names so a simple join
if self.names == other.names:
pass
else:
return self._join_multi(other, how=how, return_indexers=return_indexers)
# join on the level
if level is not None and (self_is_mi or other_is_mi):
return self._join_level(
other, level, how=how, return_indexers=return_indexers
)
other = ensure_index(other)
if len(other) == 0 and how in ("left", "outer"):
join_index = self._shallow_copy()
if return_indexers:
rindexer = np.repeat(-1, len(join_index))
return join_index, None, rindexer
else:
return join_index
if len(self) == 0 and how in ("right", "outer"):
join_index = other._shallow_copy()
if return_indexers:
lindexer = np.repeat(-1, len(join_index))
return join_index, lindexer, None
else:
return join_index
if self._join_precedence < other._join_precedence:
how = {"right": "left", "left": "right"}.get(how, how)
result = other.join(
self, how=how, level=level, return_indexers=return_indexers
)
if return_indexers:
x, y, z = result
result = x, z, y
return result
if not is_dtype_equal(self.dtype, other.dtype):
this = self.astype("O")
other = other.astype("O")
return this.join(other, how=how, return_indexers=return_indexers)
_validate_join_method(how)
if not self.is_unique and not other.is_unique:
return self._join_non_unique(
other, how=how, return_indexers=return_indexers
)
elif not self.is_unique or not other.is_unique:
if self.is_monotonic and other.is_monotonic:
return self._join_monotonic(
other, how=how, return_indexers=return_indexers
)
else:
return self._join_non_unique(
other, how=how, return_indexers=return_indexers
)
elif self.is_monotonic and other.is_monotonic:
try:
return self._join_monotonic(
other, how=how, return_indexers=return_indexers
)
except TypeError:
pass
if how == "left":
join_index = self
elif how == "right":
join_index = other
elif how == "inner":
# TODO: sort=False here for backwards compat. It may
# be better to use the sort parameter passed into join
join_index = self.intersection(other, sort=False)
elif how == "outer":
# TODO: sort=True here for backwards compat. It may
# be better to use the sort parameter passed into join
join_index = self.union(other)
if sort:
join_index = join_index.sort_values()
if return_indexers:
if join_index is self:
lindexer = None
else:
lindexer = self.get_indexer(join_index)
if join_index is other:
rindexer = None
else:
rindexer = other.get_indexer(join_index)
return join_index, lindexer, rindexer
else:
return join_index
def _join_multi(self, other, how, return_indexers=True):
from .multi import MultiIndex
from pandas.core.reshape.merge import _restore_dropped_levels_multijoin
# figure out join names
self_names = set(com.not_none(*self.names))
other_names = set(com.not_none(*other.names))
overlap = self_names & other_names
# need at least 1 in common
if not overlap:
raise ValueError("cannot join with no overlapping index names")
self_is_mi = isinstance(self, MultiIndex)
other_is_mi = isinstance(other, MultiIndex)
if self_is_mi and other_is_mi:
# Drop the non-matching levels from left and right respectively
ldrop_names = list(self_names - overlap)
rdrop_names = list(other_names - overlap)
# if only the order differs
if not len(ldrop_names + rdrop_names):
self_jnlevels = self
other_jnlevels = other.reorder_levels(self.names)
else:
self_jnlevels = self.droplevel(ldrop_names)
other_jnlevels = other.droplevel(rdrop_names)
# Join left and right
# Join on same leveled multi-index frames is supported
join_idx, lidx, ridx = self_jnlevels.join(
other_jnlevels, how, return_indexers=True
)
# Restore the dropped levels
# Returned index level order is
# common levels, ldrop_names, rdrop_names
dropped_names = ldrop_names + rdrop_names
levels, codes, names = _restore_dropped_levels_multijoin(
self, other, dropped_names, join_idx, lidx, ridx
)
# Re-create the multi-index
multi_join_idx = MultiIndex(
levels=levels, codes=codes, names=names, verify_integrity=False
)
multi_join_idx = multi_join_idx.remove_unused_levels()
return multi_join_idx, lidx, ridx
jl = list(overlap)[0]
# Case where only one index is multi
# make the indices into mi's that match
flip_order = False
if self_is_mi:
self, other = other, self
flip_order = True
# flip if join method is right or left
how = {"right": "left", "left": "right"}.get(how, how)
level = other.names.index(jl)
result = self._join_level(
other, level, how=how, return_indexers=return_indexers
)
if flip_order:
if isinstance(result, tuple):
return result[0], result[2], result[1]
return result
def _join_non_unique(self, other, how="left", return_indexers=False):
from pandas.core.reshape.merge import _get_join_indexers
left_idx, right_idx = _get_join_indexers(
[self._ndarray_values], [other._ndarray_values], how=how, sort=True
)
left_idx = ensure_platform_int(left_idx)
right_idx = ensure_platform_int(right_idx)
join_index = np.asarray(self._ndarray_values.take(left_idx))
mask = left_idx == -1
np.putmask(join_index, mask, other._ndarray_values.take(right_idx))
join_index = self._wrap_joined_index(join_index, other)
if return_indexers:
return join_index, left_idx, right_idx
else:
return join_index
def _join_level(
self, other, level, how="left", return_indexers=False, keep_order=True
):
"""
The join method *only* affects the level of the resulting
MultiIndex. Otherwise it just exactly aligns the Index data to the
labels of the level in the MultiIndex.
If ```keep_order == True```, the order of the data indexed by the
MultiIndex will not be changed; otherwise, it will tie out
with `other`.
"""
from .multi import MultiIndex
def _get_leaf_sorter(labels):
"""
Returns sorter for the inner most level while preserving the
order of higher levels.
"""
if labels[0].size == 0:
return np.empty(0, dtype="int64")
if len(labels) == 1:
lab = ensure_int64(labels[0])
sorter, _ = libalgos.groupsort_indexer(lab, 1 + lab.max())
return sorter
# find indexers of beginning of each set of
# same-key labels w.r.t all but last level
tic = labels[0][:-1] != labels[0][1:]
for lab in labels[1:-1]:
tic |= lab[:-1] != lab[1:]
starts = np.hstack(([True], tic, [True])).nonzero()[0]
lab = ensure_int64(labels[-1])
return lib.get_level_sorter(lab, ensure_int64(starts))
if isinstance(self, MultiIndex) and isinstance(other, MultiIndex):
raise TypeError("Join on level between two MultiIndex objects is ambiguous")
left, right = self, other
flip_order = not isinstance(self, MultiIndex)
if flip_order:
left, right = right, left
how = {"right": "left", "left": "right"}.get(how, how)
level = left._get_level_number(level)
old_level = left.levels[level]
if not right.is_unique:
raise NotImplementedError(
"Index._join_level on non-unique index is not implemented"
)
new_level, left_lev_indexer, right_lev_indexer = old_level.join(
right, how=how, return_indexers=True
)
if left_lev_indexer is None:
if keep_order or len(left) == 0:
left_indexer = None
join_index = left
else: # sort the leaves
left_indexer = _get_leaf_sorter(left.codes[: level + 1])
join_index = left[left_indexer]
else:
left_lev_indexer = ensure_int64(left_lev_indexer)
rev_indexer = lib.get_reverse_indexer(left_lev_indexer, len(old_level))
new_lev_codes = algos.take_nd(
rev_indexer, left.codes[level], allow_fill=False
)
new_codes = list(left.codes)
new_codes[level] = new_lev_codes
new_levels = list(left.levels)
new_levels[level] = new_level
if keep_order: # just drop missing values. o.w. keep order
left_indexer = np.arange(len(left), dtype=np.intp)
mask = new_lev_codes != -1
if not mask.all():
new_codes = [lab[mask] for lab in new_codes]
left_indexer = left_indexer[mask]
else: # tie out the order with other
if level == 0: # outer most level, take the fast route
ngroups = 1 + new_lev_codes.max()
left_indexer, counts = libalgos.groupsort_indexer(
new_lev_codes, ngroups
)
# missing values are placed first; drop them!
left_indexer = left_indexer[counts[0] :]
new_codes = [lab[left_indexer] for lab in new_codes]
else: # sort the leaves
mask = new_lev_codes != -1
mask_all = mask.all()
if not mask_all:
new_codes = [lab[mask] for lab in new_codes]
left_indexer = _get_leaf_sorter(new_codes[: level + 1])
new_codes = [lab[left_indexer] for lab in new_codes]
# left_indexers are w.r.t masked frame.
# reverse to original frame!
if not mask_all:
left_indexer = mask.nonzero()[0][left_indexer]
join_index = MultiIndex(
levels=new_levels,
codes=new_codes,
names=left.names,
verify_integrity=False,
)
if right_lev_indexer is not None:
right_indexer = algos.take_nd(
right_lev_indexer, join_index.codes[level], allow_fill=False
)
else:
right_indexer = join_index.codes[level]
if flip_order:
left_indexer, right_indexer = right_indexer, left_indexer
if return_indexers:
left_indexer = (
None if left_indexer is None else ensure_platform_int(left_indexer)
)
right_indexer = (
None if right_indexer is None else ensure_platform_int(right_indexer)
)
return join_index, left_indexer, right_indexer
else:
return join_index
def _join_monotonic(self, other, how="left", return_indexers=False):
if self.equals(other):
ret_index = other if how == "right" else self
if return_indexers:
return ret_index, None, None
else:
return ret_index
sv = self._ndarray_values
ov = other._ndarray_values
if self.is_unique and other.is_unique:
# We can perform much better than the general case
if how == "left":
join_index = self
lidx = None
ridx = self._left_indexer_unique(sv, ov)
elif how == "right":
join_index = other
lidx = self._left_indexer_unique(ov, sv)
ridx = None
elif how == "inner":
join_index, lidx, ridx = self._inner_indexer(sv, ov)
join_index = self._wrap_joined_index(join_index, other)
elif how == "outer":
join_index, lidx, ridx = self._outer_indexer(sv, ov)
join_index = self._wrap_joined_index(join_index, other)
else:
if how == "left":
join_index, lidx, ridx = self._left_indexer(sv, ov)
elif how == "right":
join_index, ridx, lidx = self._left_indexer(ov, sv)
elif how == "inner":
join_index, lidx, ridx = self._inner_indexer(sv, ov)
elif how == "outer":
join_index, lidx, ridx = self._outer_indexer(sv, ov)
join_index = self._wrap_joined_index(join_index, other)
if return_indexers:
lidx = None if lidx is None else ensure_platform_int(lidx)
ridx = None if ridx is None else ensure_platform_int(ridx)
return join_index, lidx, ridx
else:
return join_index
def _wrap_joined_index(self, joined, other):
name = get_op_result_name(self, other)
return Index(joined, name=name)
# --------------------------------------------------------------------
# Uncategorized Methods
@property
def values(self):
"""
Return an array representing the data in the Index.
.. warning::
We recommend using :attr:`Index.array` or
:meth:`Index.to_numpy`, depending on whether you need
a reference to the underlying data or a NumPy array.
Returns
-------
array: numpy.ndarray or ExtensionArray
See Also
--------
Index.array : Reference to the underlying data.
Index.to_numpy : A NumPy array representing the underlying data.
"""
return self._data.view(np.ndarray)
@property
def _values(self) -> Union[ExtensionArray, ABCIndexClass, np.ndarray]:
# TODO(EA): remove index types as they become extension arrays
"""
The best array representation.
This is an ndarray, ExtensionArray, or Index subclass. This differs
from ``_ndarray_values``, which always returns an ndarray.
Both ``_values`` and ``_ndarray_values`` are consistent between
``Series`` and ``Index``.
It may differ from the public '.values' method.
index | values | _values | _ndarray_values |
----------------- | --------------- | ------------- | --------------- |
Index | ndarray | ndarray | ndarray |
CategoricalIndex | Categorical | Categorical | ndarray[int] |
DatetimeIndex | ndarray[M8ns] | ndarray[M8ns] | ndarray[M8ns] |
DatetimeIndex[tz] | ndarray[M8ns] | DTI[tz] | ndarray[M8ns] |
PeriodIndex | ndarray[object] | PeriodArray | ndarray[int] |
IntervalIndex | IntervalArray | IntervalArray | ndarray[object] |
See Also
--------
values
_ndarray_values
"""
return self._data
def _internal_get_values(self):
"""
Return `Index` data as an `numpy.ndarray`.
Returns
-------
numpy.ndarray
A one-dimensional numpy array of the `Index` values.
See Also
--------
Index.values : The attribute that _internal_get_values wraps.
Examples
--------
Getting the `Index` values of a `DataFrame`:
>>> df = pd.DataFrame([[1, 2, 3], [4, 5, 6], [7, 8, 9]],
... index=['a', 'b', 'c'], columns=['A', 'B', 'C'])
>>> df
A B C
a 1 2 3
b 4 5 6
c 7 8 9
>>> df.index._internal_get_values()
array(['a', 'b', 'c'], dtype=object)
Standalone `Index` values:
>>> idx = pd.Index(['1', '2', '3'])
>>> idx._internal_get_values()
array(['1', '2', '3'], dtype=object)
`MultiIndex` arrays also have only one dimension:
>>> midx = pd.MultiIndex.from_arrays([[1, 2, 3], ['a', 'b', 'c']],
... names=('number', 'letter'))
>>> midx._internal_get_values()
array([(1, 'a'), (2, 'b'), (3, 'c')], dtype=object)
>>> midx._internal_get_values().ndim
1
"""
return self.values
@Appender(IndexOpsMixin.memory_usage.__doc__)
def memory_usage(self, deep=False):
result = super().memory_usage(deep=deep)
# include our engine hashtable
result += self._engine.sizeof(deep=deep)
return result
_index_shared_docs[
"where"
] = """
Return an Index of same shape as self and whose corresponding
entries are from self where cond is True and otherwise are from
other.
Parameters
----------
cond : bool array-like with the same length as self
other : scalar, or array-like
Returns
-------
Index
"""
@Appender(_index_shared_docs["where"])
def where(self, cond, other=None):
if other is None:
other = self._na_value
dtype = self.dtype
values = self.values
if is_bool(other) or is_bool_dtype(other):
# bools force casting
values = values.astype(object)
dtype = None
values = np.where(cond, values, other)
if self._is_numeric_dtype and np.any(isna(values)):
# We can't coerce to the numeric dtype of "self" (unless
# it's float) if there are NaN values in our output.
dtype = None
return self._shallow_copy_with_infer(values, dtype=dtype)
# construction helpers
@classmethod
def _scalar_data_error(cls, data):
# We return the TypeError so that we can raise it from the constructor
# in order to keep mypy happy
return TypeError(
f"{cls.__name__}(...) must be called with a collection of some "
f"kind, {repr(data)} was passed"
)
@classmethod
def _string_data_error(cls, data):
raise TypeError(
"String dtype not supported, you may need "
"to explicitly cast to a numeric type"
)
def _coerce_scalar_to_index(self, item):
"""
We need to coerce a scalar to a compat for our index type.
Parameters
----------
item : scalar item to coerce
"""
dtype = self.dtype
if self._is_numeric_dtype and isna(item):
# We can't coerce to the numeric dtype of "self" (unless
# it's float) if there are NaN values in our output.
dtype = None
return Index([item], dtype=dtype, **self._get_attributes_dict())
def _to_safe_for_reshape(self):
"""
Convert to object if we are a categorical.
"""
return self
def _convert_for_op(self, value):
"""
Convert value to be insertable to ndarray.
"""
return value
def _assert_can_do_op(self, value):
"""
Check value is valid for scalar op.
"""
if not is_scalar(value):
raise TypeError(f"'value' must be a scalar, passed: {type(value).__name__}")
def _is_memory_usage_qualified(self) -> bool:
"""
Return a boolean if we need a qualified .info display.
"""
return self.is_object()
def is_type_compatible(self, kind) -> bool:
"""
Whether the index type is compatible with the provided type.
"""
return kind == self.inferred_type
_index_shared_docs[
"contains"
] = """
Return a boolean indicating whether the provided key is in the index.
Parameters
----------
key : label
The key to check if it is present in the index.
Returns
-------
bool
Whether the key search is in the index.
See Also
--------
Index.isin : Returns an ndarray of boolean dtype indicating whether the
list-like key is in the index.
Examples
--------
>>> idx = pd.Index([1, 2, 3, 4])
>>> idx
Int64Index([1, 2, 3, 4], dtype='int64')
>>> 2 in idx
True
>>> 6 in idx
False
"""
@Appender(_index_shared_docs["contains"] % _index_doc_kwargs)
def __contains__(self, key) -> bool:
hash(key)
try:
return key in self._engine
except (OverflowError, TypeError, ValueError):
return False
def __hash__(self):
raise TypeError(f"unhashable type: {repr(type(self).__name__)}")
def __setitem__(self, key, value):
raise TypeError("Index does not support mutable operations")
def __getitem__(self, key):
"""
Override numpy.ndarray's __getitem__ method to work as desired.
This function adds lists and Series as valid boolean indexers
(ndarrays only supports ndarray with dtype=bool).
If resulting ndim != 1, plain ndarray is returned instead of
corresponding `Index` subclass.
"""
# There's no custom logic to be implemented in __getslice__, so it's
# not overloaded intentionally.
getitem = self._data.__getitem__
promote = self._shallow_copy
if is_scalar(key):
key = com.cast_scalar_indexer(key)
return getitem(key)
if isinstance(key, slice):
# This case is separated from the conditional above to avoid
# pessimization of basic indexing.
return promote(getitem(key))
if com.is_bool_indexer(key):
key = np.asarray(key, dtype=bool)
key = com.values_from_object(key)
result = getitem(key)
if not is_scalar(result):
return promote(result)
else:
return result
def _can_hold_identifiers_and_holds_name(self, name) -> bool:
"""
Faster check for ``name in self`` when we know `name` is a Python
identifier (e.g. in NDFrame.__getattr__, which hits this to support
. key lookup). For indexes that can't hold identifiers (everything
but object & categorical) we just return False.
https://github.com/pandas-dev/pandas/issues/19764
"""
if self.is_object() or self.is_categorical():
return name in self
return False
def append(self, other):
"""
Append a collection of Index options together.
Parameters
----------
other : Index or list/tuple of indices
Returns
-------
appended : Index
"""
to_concat = [self]
if isinstance(other, (list, tuple)):
to_concat = to_concat + list(other)
else:
to_concat.append(other)
for obj in to_concat:
if not isinstance(obj, Index):
raise TypeError("all inputs must be Index")
names = {obj.name for obj in to_concat}
name = None if len(names) > 1 else self.name
return self._concat(to_concat, name)
def _concat(self, to_concat, name):
typs = _concat.get_dtype_kinds(to_concat)
if len(typs) == 1:
return self._concat_same_dtype(to_concat, name=name)
return Index._concat_same_dtype(self, to_concat, name=name)
def _concat_same_dtype(self, to_concat, name):
"""
Concatenate to_concat which has the same class.
"""
# must be overridden in specific classes
klasses = (
ABCDatetimeIndex,
ABCTimedeltaIndex,
ABCPeriodIndex,
ExtensionArray,
ABCIntervalIndex,
)
to_concat = [
x.astype(object) if isinstance(x, klasses) else x for x in to_concat
]
self = to_concat[0]
attribs = self._get_attributes_dict()
attribs["name"] = name
to_concat = [x._values if isinstance(x, Index) else x for x in to_concat]
return self._shallow_copy_with_infer(np.concatenate(to_concat), **attribs)
def putmask(self, mask, value):
"""
Return a new Index of the values set with the mask.
Returns
-------
Index
See Also
--------
numpy.ndarray.putmask
"""
values = self.values.copy()
try:
np.putmask(values, mask, self._convert_for_op(value))
return self._shallow_copy(values)
except (ValueError, TypeError) as err:
if is_object_dtype(self):
raise err
# coerces to object
return self.astype(object).putmask(mask, value)
def equals(self, other) -> bool:
"""
Determine if two Index objects contain the same elements.
Returns
-------
bool
True if "other" is an Index and it has the same elements as calling
index; False otherwise.
"""
if self.is_(other):
return True
if not isinstance(other, Index):
return False
if is_object_dtype(self) and not is_object_dtype(other):
# if other is not object, use other's logic for coercion
return other.equals(self)
if isinstance(other, ABCMultiIndex):
# d-level MultiIndex can equal d-tuple Index
if not is_object_dtype(self.dtype):
if self.nlevels != other.nlevels:
return False
return array_equivalent(
com.values_from_object(self), com.values_from_object(other)
)
def identical(self, other) -> bool:
"""
Similar to equals, but check that other comparable attributes are
also equal.
Returns
-------
bool
If two Index objects have equal elements and same type True,
otherwise False.
"""
return (
self.equals(other)
and all(
(
getattr(self, c, None) == getattr(other, c, None)
for c in self._comparables
)
)
and type(self) == type(other)
)
def asof(self, label):
"""
Return the label from the index, or, if not present, the previous one.
Assuming that the index is sorted, return the passed index label if it
is in the index, or return the previous index label if the passed one
is not in the index.
Parameters
----------
label : object
The label up to which the method returns the latest index label.
Returns
-------
object
The passed label if it is in the index. The previous label if the
passed label is not in the sorted index or `NaN` if there is no
such label.
See Also
--------
Series.asof : Return the latest value in a Series up to the
passed index.
merge_asof : Perform an asof merge (similar to left join but it
matches on nearest key rather than equal key).
Index.get_loc : An `asof` is a thin wrapper around `get_loc`
with method='pad'.
Examples
--------
`Index.asof` returns the latest index label up to the passed label.
>>> idx = pd.Index(['2013-12-31', '2014-01-02', '2014-01-03'])
>>> idx.asof('2014-01-01')
'2013-12-31'
If the label is in the index, the method returns the passed label.
>>> idx.asof('2014-01-02')
'2014-01-02'
If all of the labels in the index are later than the passed label,
NaN is returned.
>>> idx.asof('1999-01-02')
nan
If the index is not sorted, an error is raised.
>>> idx_not_sorted = pd.Index(['2013-12-31', '2015-01-02',
... '2014-01-03'])
>>> idx_not_sorted.asof('2013-12-31')
Traceback (most recent call last):
ValueError: index must be monotonic increasing or decreasing
"""
try:
loc = self.get_loc(label, method="pad")
except KeyError:
return self._na_value
else:
if isinstance(loc, slice):
loc = loc.indices(len(self))[-1]
return self[loc]
def asof_locs(self, where, mask):
"""
Find the locations (indices) of the labels from the index for
every entry in the `where` argument.
As in the `asof` function, if the label (a particular entry in
`where`) is not in the index, the latest index label up to the
passed label is chosen and its index returned.
If all of the labels in the index are later than a label in `where`,
-1 is returned.
`mask` is used to ignore NA values in the index during calculation.
Parameters
----------
where : Index
An Index consisting of an array of timestamps.
mask : array-like
Array of booleans denoting where values in the original
data are not NA.
Returns
-------
numpy.ndarray
An array of locations (indices) of the labels from the Index
which correspond to the return values of the `asof` function
for every element in `where`.
"""
locs = self.values[mask].searchsorted(where.values, side="right")
locs = np.where(locs > 0, locs - 1, 0)
result = np.arange(len(self))[mask].take(locs)
first = mask.argmax()
result[(locs == 0) & (where.values < self.values[first])] = -1
return result
def sort_values(self, return_indexer=False, ascending=True):
"""
Return a sorted copy of the index.
Return a sorted copy of the index, and optionally return the indices
that sorted the index itself.
Parameters
----------
return_indexer : bool, default False
Should the indices that would sort the index be returned.
ascending : bool, default True
Should the index values be sorted in an ascending order.
Returns
-------
sorted_index : pandas.Index
Sorted copy of the index.
indexer : numpy.ndarray, optional
The indices that the index itself was sorted by.
See Also
--------
Series.sort_values : Sort values of a Series.
DataFrame.sort_values : Sort values in a DataFrame.
Examples
--------
>>> idx = pd.Index([10, 100, 1, 1000])
>>> idx
Int64Index([10, 100, 1, 1000], dtype='int64')
Sort values in ascending order (default behavior).
>>> idx.sort_values()
Int64Index([1, 10, 100, 1000], dtype='int64')
Sort values in descending order, and also get the indices `idx` was
sorted by.
>>> idx.sort_values(ascending=False, return_indexer=True)
(Int64Index([1000, 100, 10, 1], dtype='int64'), array([3, 1, 0, 2]))
"""
_as = self.argsort()
if not ascending:
_as = _as[::-1]
sorted_index = self.take(_as)
if return_indexer:
return sorted_index, _as
else:
return sorted_index
def sort(self, *args, **kwargs):
"""
Use sort_values instead.
"""
raise TypeError("cannot sort an Index object in-place, use sort_values instead")
def shift(self, periods=1, freq=None):
"""
Shift index by desired number of time frequency increments.
This method is for shifting the values of datetime-like indexes
by a specified time increment a given number of times.
Parameters
----------
periods : int, default 1
Number of periods (or increments) to shift by,
can be positive or negative.
freq : pandas.DateOffset, pandas.Timedelta or str, optional
Frequency increment to shift by.
If None, the index is shifted by its own `freq` attribute.
Offset aliases are valid strings, e.g., 'D', 'W', 'M' etc.
Returns
-------
pandas.Index
Shifted index.
See Also
--------
Series.shift : Shift values of Series.
Notes
-----
This method is only implemented for datetime-like index classes,
i.e., DatetimeIndex, PeriodIndex and TimedeltaIndex.
Examples
--------
Put the first 5 month starts of 2011 into an index.
>>> month_starts = pd.date_range('1/1/2011', periods=5, freq='MS')
>>> month_starts
DatetimeIndex(['2011-01-01', '2011-02-01', '2011-03-01', '2011-04-01',
'2011-05-01'],
dtype='datetime64[ns]', freq='MS')
Shift the index by 10 days.
>>> month_starts.shift(10, freq='D')
DatetimeIndex(['2011-01-11', '2011-02-11', '2011-03-11', '2011-04-11',
'2011-05-11'],
dtype='datetime64[ns]', freq=None)
The default value of `freq` is the `freq` attribute of the index,
which is 'MS' (month start) in this example.
>>> month_starts.shift(10)
DatetimeIndex(['2011-11-01', '2011-12-01', '2012-01-01', '2012-02-01',
'2012-03-01'],
dtype='datetime64[ns]', freq='MS')
"""
raise NotImplementedError(f"Not supported for type {type(self).__name__}")
def argsort(self, *args, **kwargs):
"""
Return the integer indices that would sort the index.
Parameters
----------
*args
Passed to `numpy.ndarray.argsort`.
**kwargs
Passed to `numpy.ndarray.argsort`.
Returns
-------
numpy.ndarray
Integer indices that would sort the index if used as
an indexer.
See Also
--------
numpy.argsort : Similar method for NumPy arrays.
Index.sort_values : Return sorted copy of Index.
Examples
--------
>>> idx = pd.Index(['b', 'a', 'd', 'c'])
>>> idx
Index(['b', 'a', 'd', 'c'], dtype='object')
>>> order = idx.argsort()
>>> order
array([1, 0, 3, 2])
>>> idx[order]
Index(['a', 'b', 'c', 'd'], dtype='object')
"""
result = self.asi8
if result is None:
result = np.array(self)
return result.argsort(*args, **kwargs)
_index_shared_docs[
"get_value"
] = """
Fast lookup of value from 1-dimensional ndarray. Only use this if you
know what you're doing.
Returns
-------
scalar
A value in the Series with the index of the key value in self.
"""
@Appender(_index_shared_docs["get_value"] % _index_doc_kwargs)
def get_value(self, series, key):
# if we have something that is Index-like, then
# use this, e.g. DatetimeIndex
# Things like `Series._get_value` (via .at) pass the EA directly here.
s = extract_array(series, extract_numpy=True)
if isinstance(s, ExtensionArray):
if is_scalar(key):
# GH 20882, 21257
# First try to convert the key to a location
# If that fails, raise a KeyError if an integer
# index, otherwise, see if key is an integer, and
# try that
try:
iloc = self.get_loc(key)
return s[iloc]
except KeyError:
if len(self) > 0 and (self.holds_integer() or self.is_boolean()):
raise
elif is_integer(key):
return s[key]
else:
# if key is not a scalar, directly raise an error (the code below
# would convert to numpy arrays and raise later any way) - GH29926
raise InvalidIndexError(key)
s = com.values_from_object(series)
k = com.values_from_object(key)
k = self._convert_scalar_indexer(k, kind="getitem")
try:
return self._engine.get_value(s, k, tz=getattr(series.dtype, "tz", None))
except KeyError as e1:
if len(self) > 0 and (self.holds_integer() or self.is_boolean()):
raise
try:
return libindex.get_value_at(s, key)
except IndexError:
raise
except TypeError:
# generator/iterator-like
if is_iterator(key):
raise InvalidIndexError(key)
else:
raise e1
except Exception:
raise e1
except TypeError:
# e.g. "[False] is an invalid key"
if is_scalar(key):
raise IndexError(key)
raise InvalidIndexError(key)
def set_value(self, arr, key, value):
"""
Fast lookup of value from 1-dimensional ndarray.
.. deprecated:: 1.0
Notes
-----
Only use this if you know what you're doing.
"""
warnings.warn(
(
"The 'set_value' method is deprecated, and "
"will be removed in a future version."
),
FutureWarning,
stacklevel=2,
)
self._engine.set_value(
com.values_from_object(arr), com.values_from_object(key), value
)
_index_shared_docs[
"get_indexer_non_unique"
] = """
Compute indexer and mask for new index given the current index. The
indexer should be then used as an input to ndarray.take to align the
current data to the new index.
Parameters
----------
target : %(target_klass)s
Returns
-------
indexer : ndarray of int
Integers from 0 to n - 1 indicating that the index at these
positions matches the corresponding target values. Missing values
in the target are marked by -1.
missing : ndarray of int
An indexer into the target of the values not found.
These correspond to the -1 in the indexer array.
"""
@Appender(_index_shared_docs["get_indexer_non_unique"] % _index_doc_kwargs)
def get_indexer_non_unique(self, target):
target = ensure_index(target)
pself, ptarget = self._maybe_promote(target)
if pself is not self or ptarget is not target:
return pself.get_indexer_non_unique(ptarget)
if is_categorical(target):
tgt_values = np.asarray(target)
elif self.is_all_dates and target.is_all_dates: # GH 30399
tgt_values = target.asi8
else:
tgt_values = target._ndarray_values
indexer, missing = self._engine.get_indexer_non_unique(tgt_values)
return ensure_platform_int(indexer), missing
def get_indexer_for(self, target, **kwargs):
"""
Guaranteed return of an indexer even when non-unique.
This dispatches to get_indexer or get_indexer_non_unique
as appropriate.
Returns
-------
numpy.ndarray
List of indices.
"""
if self.is_unique:
return self.get_indexer(target, **kwargs)
indexer, _ = self.get_indexer_non_unique(target, **kwargs)
return indexer
def _maybe_promote(self, other):
# A hack, but it works
if self.inferred_type == "date" and isinstance(other, ABCDatetimeIndex):
return type(other)(self), other
elif self.inferred_type == "boolean":
if not is_object_dtype(self.dtype):
return self.astype("object"), other.astype("object")
return self, other
def groupby(self, values) -> Dict[Hashable, np.ndarray]:
"""
Group the index labels by a given array of values.
Parameters
----------
values : array
Values used to determine the groups.
Returns
-------
dict
{group name -> group labels}
"""
# TODO: if we are a MultiIndex, we can do better
# that converting to tuples
if isinstance(values, ABCMultiIndex):
values = values.values
values = ensure_categorical(values)
result = values._reverse_indexer()
# map to the label
result = {k: self.take(v) for k, v in result.items()}
return result
def map(self, mapper, na_action=None):
"""
Map values using input correspondence (a dict, Series, or function).
Parameters
----------
mapper : function, dict, or Series
Mapping correspondence.
na_action : {None, 'ignore'}
If 'ignore', propagate NA values, without passing them to the
mapping correspondence.
Returns
-------
applied : Union[Index, MultiIndex], inferred
The output of the mapping function applied to the index.
If the function returns a tuple with more than one element
a MultiIndex will be returned.
"""
from .multi import MultiIndex
new_values = super()._map_values(mapper, na_action=na_action)
attributes = self._get_attributes_dict()
# we can return a MultiIndex
if new_values.size and isinstance(new_values[0], tuple):
if isinstance(self, MultiIndex):
names = self.names
elif attributes.get("name"):
names = [attributes.get("name")] * len(new_values[0])
else:
names = None
return MultiIndex.from_tuples(new_values, names=names)
attributes["copy"] = False
if not new_values.size:
# empty
attributes["dtype"] = self.dtype
return Index(new_values, **attributes)
def isin(self, values, level=None):
"""
Return a boolean array where the index values are in `values`.
Compute boolean array of whether each index value is found in the
passed set of values. The length of the returned boolean array matches
the length of the index.
Parameters
----------
values : set or list-like
Sought values.
level : str or int, optional
Name or position of the index level to use (if the index is a
`MultiIndex`).
Returns
-------
is_contained : ndarray
NumPy array of boolean values.
See Also
--------
Series.isin : Same for Series.
DataFrame.isin : Same method for DataFrames.
Notes
-----
In the case of `MultiIndex` you must either specify `values` as a
list-like object containing tuples that are the same length as the
number of levels, or specify `level`. Otherwise it will raise a
``ValueError``.
If `level` is specified:
- if it is the name of one *and only one* index level, use that level;
- otherwise it should be a number indicating level position.
Examples
--------
>>> idx = pd.Index([1,2,3])
>>> idx
Int64Index([1, 2, 3], dtype='int64')
Check whether each index value in a list of values.
>>> idx.isin([1, 4])
array([ True, False, False])
>>> midx = pd.MultiIndex.from_arrays([[1,2,3],
... ['red', 'blue', 'green']],
... names=('number', 'color'))
>>> midx
MultiIndex(levels=[[1, 2, 3], ['blue', 'green', 'red']],
codes=[[0, 1, 2], [2, 0, 1]],
names=['number', 'color'])
Check whether the strings in the 'color' level of the MultiIndex
are in a list of colors.
>>> midx.isin(['red', 'orange', 'yellow'], level='color')
array([ True, False, False])
To check across the levels of a MultiIndex, pass a list of tuples:
>>> midx.isin([(1, 'red'), (3, 'red')])
array([ True, False, False])
For a DatetimeIndex, string values in `values` are converted to
Timestamps.
>>> dates = ['2000-03-11', '2000-03-12', '2000-03-13']
>>> dti = pd.to_datetime(dates)
>>> dti
DatetimeIndex(['2000-03-11', '2000-03-12', '2000-03-13'],
dtype='datetime64[ns]', freq=None)
>>> dti.isin(['2000-03-11'])
array([ True, False, False])
"""
if level is not None:
self._validate_index_level(level)
return algos.isin(self, values)
def _get_string_slice(self, key, use_lhs=True, use_rhs=True):
# this is for partial string indexing,
# overridden in DatetimeIndex, TimedeltaIndex and PeriodIndex
raise NotImplementedError
def slice_indexer(self, start=None, end=None, step=None, kind=None):
"""
For an ordered or unique index, compute the slice indexer for input
labels and step.
Parameters
----------
start : label, default None
If None, defaults to the beginning.
end : label, default None
If None, defaults to the end.
step : int, default None
kind : str, default None
Returns
-------
indexer : slice
Raises
------
KeyError : If key does not exist, or key is not unique and index is
not ordered.
Notes
-----
This function assumes that the data is sorted, so use at your own peril
Examples
--------
This is a method on all index types. For example you can do:
>>> idx = pd.Index(list('abcd'))
>>> idx.slice_indexer(start='b', end='c')
slice(1, 3)
>>> idx = pd.MultiIndex.from_arrays([list('abcd'), list('efgh')])
>>> idx.slice_indexer(start='b', end=('c', 'g'))
slice(1, 3)
"""
start_slice, end_slice = self.slice_locs(start, end, step=step, kind=kind)
# return a slice
if not is_scalar(start_slice):
raise AssertionError("Start slice bound is non-scalar")
if not is_scalar(end_slice):
raise AssertionError("End slice bound is non-scalar")
return slice(start_slice, end_slice, step)
def _maybe_cast_indexer(self, key):
"""
If we have a float key and are not a floating index, then try to cast
to an int if equivalent.
"""
if is_float(key) and not self.is_floating():
try:
ckey = int(key)
if ckey == key:
key = ckey
except (OverflowError, ValueError, TypeError):
pass
return key
def _validate_indexer(self, form, key, kind):
"""
If we are positional indexer, validate that we have appropriate
typed bounds must be an integer.
"""
assert kind in ["ix", "loc", "getitem", "iloc"]
if key is None:
pass
elif is_integer(key):
pass
elif kind in ["iloc", "getitem"]:
self._invalid_indexer(form, key)
return key
_index_shared_docs[
"_maybe_cast_slice_bound"
] = """
This function should be overloaded in subclasses that allow non-trivial
casting on label-slice bounds, e.g. datetime-like indices allowing
strings containing formatted datetimes.
Parameters
----------
label : object
side : {'left', 'right'}
kind : {'ix', 'loc', 'getitem'}
Returns
-------
label : object
Notes
-----
Value of `side` parameter should be validated in caller.
"""
@Appender(_index_shared_docs["_maybe_cast_slice_bound"])
def _maybe_cast_slice_bound(self, label, side, kind):
assert kind in ["ix", "loc", "getitem", None]
# We are a plain index here (sub-class override this method if they
# wish to have special treatment for floats/ints, e.g. Float64Index and
# datetimelike Indexes
# reject them
if is_float(label):
if not (kind in ["ix"] and (self.holds_integer() or self.is_floating())):
self._invalid_indexer("slice", label)
# we are trying to find integer bounds on a non-integer based index
# this is rejected (generally .loc gets you here)
elif is_integer(label):
self._invalid_indexer("slice", label)
return label
def _searchsorted_monotonic(self, label, side="left"):
if self.is_monotonic_increasing:
return self.searchsorted(label, side=side)
elif self.is_monotonic_decreasing:
# np.searchsorted expects ascending sort order, have to reverse
# everything for it to work (element ordering, search side and
# resulting value).
pos = self[::-1].searchsorted(
label, side="right" if side == "left" else "left"
)
return len(self) - pos
raise ValueError("index must be monotonic increasing or decreasing")
def get_slice_bound(self, label, side, kind):
"""
Calculate slice bound that corresponds to given label.
Returns leftmost (one-past-the-rightmost if ``side=='right'``) position
of given label.
Parameters
----------
label : object
side : {'left', 'right'}
kind : {'ix', 'loc', 'getitem'}
Returns
-------
int
Index of label.
"""
assert kind in ["ix", "loc", "getitem", None]
if side not in ("left", "right"):
raise ValueError(
f"Invalid value for side kwarg, must be either"
f" 'left' or 'right': {side}"
)
original_label = label
# For datetime indices label may be a string that has to be converted
# to datetime boundary according to its resolution.
label = self._maybe_cast_slice_bound(label, side, kind)
# we need to look up the label
try:
slc = self.get_loc(label)
except KeyError as err:
try:
return self._searchsorted_monotonic(label, side)
except ValueError:
# raise the original KeyError
raise err
if isinstance(slc, np.ndarray):
# get_loc may return a boolean array or an array of indices, which
# is OK as long as they are representable by a slice.
if is_bool_dtype(slc):
slc = lib.maybe_booleans_to_slice(slc.view("u1"))
else:
slc = lib.maybe_indices_to_slice(slc.astype("i8"), len(self))
if isinstance(slc, np.ndarray):
raise KeyError(
f"Cannot get {side} slice bound for non-unique "
f"label: {repr(original_label)}"
)
if isinstance(slc, slice):
if side == "left":
return slc.start
else:
return slc.stop
else:
if side == "right":
return slc + 1
else:
return slc
def slice_locs(self, start=None, end=None, step=None, kind=None):
"""
Compute slice locations for input labels.
Parameters
----------
start : label, default None
If None, defaults to the beginning.
end : label, default None
If None, defaults to the end.
step : int, defaults None
If None, defaults to 1.
kind : {'ix', 'loc', 'getitem'} or None
Returns
-------
start, end : int
See Also
--------
Index.get_loc : Get location for a single label.
Notes
-----
This method only works if the index is monotonic or unique.
Examples
--------
>>> idx = pd.Index(list('abcd'))
>>> idx.slice_locs(start='b', end='c')
(1, 3)
"""
inc = step is None or step >= 0
if not inc:
# If it's a reverse slice, temporarily swap bounds.
start, end = end, start
# GH 16785: If start and end happen to be date strings with UTC offsets
# attempt to parse and check that the offsets are the same
if isinstance(start, (str, datetime)) and isinstance(end, (str, datetime)):
try:
ts_start = Timestamp(start)
ts_end = Timestamp(end)
except (ValueError, TypeError):
pass
else:
if not tz_compare(ts_start.tzinfo, ts_end.tzinfo):
raise ValueError("Both dates must have the same UTC offset")
start_slice = None
if start is not None:
start_slice = self.get_slice_bound(start, "left", kind)
if start_slice is None:
start_slice = 0
end_slice = None
if end is not None:
end_slice = self.get_slice_bound(end, "right", kind)
if end_slice is None:
end_slice = len(self)
if not inc:
# Bounds at this moment are swapped, swap them back and shift by 1.
#
# slice_locs('B', 'A', step=-1): s='B', e='A'
#
# s='A' e='B'
# AFTER SWAP: | |
# v ------------------> V
# -----------------------------------
# | | |A|A|A|A| | | | | |B|B| | | | |
# -----------------------------------
# ^ <------------------ ^
# SHOULD BE: | |
# end=s-1 start=e-1
#
end_slice, start_slice = start_slice - 1, end_slice - 1
# i == -1 triggers ``len(self) + i`` selection that points to the
# last element, not before-the-first one, subtracting len(self)
# compensates that.
if end_slice == -1:
end_slice -= len(self)
if start_slice == -1:
start_slice -= len(self)
return start_slice, end_slice
def delete(self, loc):
"""
Make new Index with passed location(-s) deleted.
Returns
-------
new_index : Index
"""
return self._shallow_copy(np.delete(self._data, loc))
def insert(self, loc, item):
"""
Make new Index inserting new item at location.
Follows Python list.append semantics for negative values.
Parameters
----------
loc : int
item : object
Returns
-------
new_index : Index
"""
_self = np.asarray(self)
item = self._coerce_scalar_to_index(item)._ndarray_values
idx = np.concatenate((_self[:loc], item, _self[loc:]))
return self._shallow_copy_with_infer(idx)
def drop(self, labels, errors="raise"):
"""
Make new Index with passed list of labels deleted.
Parameters
----------
labels : array-like
errors : {'ignore', 'raise'}, default 'raise'
If 'ignore', suppress error and existing labels are dropped.
Returns
-------
dropped : Index
Raises
------
KeyError
If not all of the labels are found in the selected axis
"""
arr_dtype = "object" if self.dtype == "object" else None
labels = com.index_labels_to_array(labels, dtype=arr_dtype)
indexer = self.get_indexer(labels)
mask = indexer == -1
if mask.any():
if errors != "ignore":
raise KeyError(f"{labels[mask]} not found in axis")
indexer = indexer[~mask]
return self.delete(indexer)
# --------------------------------------------------------------------
# Generated Arithmetic, Comparison, and Unary Methods
@classmethod
def _add_comparison_methods(cls):
"""
Add in comparison methods.
"""
cls.__eq__ = _make_comparison_op(operator.eq, cls)
cls.__ne__ = _make_comparison_op(operator.ne, cls)
cls.__lt__ = _make_comparison_op(operator.lt, cls)
cls.__gt__ = _make_comparison_op(operator.gt, cls)
cls.__le__ = _make_comparison_op(operator.le, cls)
cls.__ge__ = _make_comparison_op(operator.ge, cls)
@classmethod
def _add_numeric_methods_add_sub_disabled(cls):
"""
Add in the numeric add/sub methods to disable.
"""
cls.__add__ = make_invalid_op("__add__")
cls.__radd__ = make_invalid_op("__radd__")
cls.__iadd__ = make_invalid_op("__iadd__")
cls.__sub__ = make_invalid_op("__sub__")
cls.__rsub__ = make_invalid_op("__rsub__")
cls.__isub__ = make_invalid_op("__isub__")
@classmethod
def _add_numeric_methods_disabled(cls):
"""
Add in numeric methods to disable other than add/sub.
"""
cls.__pow__ = make_invalid_op("__pow__")
cls.__rpow__ = make_invalid_op("__rpow__")
cls.__mul__ = make_invalid_op("__mul__")
cls.__rmul__ = make_invalid_op("__rmul__")
cls.__floordiv__ = make_invalid_op("__floordiv__")
cls.__rfloordiv__ = make_invalid_op("__rfloordiv__")
cls.__truediv__ = make_invalid_op("__truediv__")
cls.__rtruediv__ = make_invalid_op("__rtruediv__")
cls.__mod__ = make_invalid_op("__mod__")
cls.__divmod__ = make_invalid_op("__divmod__")
cls.__neg__ = make_invalid_op("__neg__")
cls.__pos__ = make_invalid_op("__pos__")
cls.__abs__ = make_invalid_op("__abs__")
cls.__inv__ = make_invalid_op("__inv__")
@classmethod
def _add_numeric_methods_binary(cls):
"""
Add in numeric methods.
"""
cls.__add__ = _make_arithmetic_op(operator.add, cls)
cls.__radd__ = _make_arithmetic_op(ops.radd, cls)
cls.__sub__ = _make_arithmetic_op(operator.sub, cls)
cls.__rsub__ = _make_arithmetic_op(ops.rsub, cls)
cls.__rpow__ = _make_arithmetic_op(ops.rpow, cls)
cls.__pow__ = _make_arithmetic_op(operator.pow, cls)
cls.__truediv__ = _make_arithmetic_op(operator.truediv, cls)
cls.__rtruediv__ = _make_arithmetic_op(ops.rtruediv, cls)
# TODO: rmod? rdivmod?
cls.__mod__ = _make_arithmetic_op(operator.mod, cls)
cls.__floordiv__ = _make_arithmetic_op(operator.floordiv, cls)
cls.__rfloordiv__ = _make_arithmetic_op(ops.rfloordiv, cls)
cls.__divmod__ = _make_arithmetic_op(divmod, cls)
cls.__mul__ = _make_arithmetic_op(operator.mul, cls)
cls.__rmul__ = _make_arithmetic_op(ops.rmul, cls)
@classmethod
def _add_numeric_methods_unary(cls):
"""
Add in numeric unary methods.
"""
def _make_evaluate_unary(op, opstr):
def _evaluate_numeric_unary(self):
attrs = self._get_attributes_dict()
return Index(op(self.values), **attrs)
_evaluate_numeric_unary.__name__ = opstr
return _evaluate_numeric_unary
cls.__neg__ = _make_evaluate_unary(operator.neg, "__neg__")
cls.__pos__ = _make_evaluate_unary(operator.pos, "__pos__")
cls.__abs__ = _make_evaluate_unary(np.abs, "__abs__")
cls.__inv__ = _make_evaluate_unary(lambda x: -x, "__inv__")
@classmethod
def _add_numeric_methods(cls):
cls._add_numeric_methods_unary()
cls._add_numeric_methods_binary()
@classmethod
def _add_logical_methods(cls):
"""
Add in logical methods.
"""
_doc = """
%(desc)s
Parameters
----------
*args
These parameters will be passed to numpy.%(outname)s.
**kwargs
These parameters will be passed to numpy.%(outname)s.
Returns
-------
%(outname)s : bool or array_like (if axis is specified)
A single element array_like may be converted to bool."""
_index_shared_docs["index_all"] = dedent(
"""
See Also
--------
Index.any : Return whether any element in an Index is True.
Series.any : Return whether any element in a Series is True.
Series.all : Return whether all elements in a Series are True.
Notes
-----
Not a Number (NaN), positive infinity and negative infinity
evaluate to True because these are not equal to zero.
Examples
--------
**all**
True, because nonzero integers are considered True.
>>> pd.Index([1, 2, 3]).all()
True
False, because ``0`` is considered False.
>>> pd.Index([0, 1, 2]).all()
False
**any**
True, because ``1`` is considered True.
>>> pd.Index([0, 0, 1]).any()
True
False, because ``0`` is considered False.
>>> pd.Index([0, 0, 0]).any()
False
"""
)
_index_shared_docs["index_any"] = dedent(
"""
See Also
--------
Index.all : Return whether all elements are True.
Series.all : Return whether all elements are True.
Notes
-----
Not a Number (NaN), positive infinity and negative infinity
evaluate to True because these are not equal to zero.
Examples
--------
>>> index = pd.Index([0, 1, 2])
>>> index.any()
True
>>> index = pd.Index([0, 0, 0])
>>> index.any()
False
"""
)
def _make_logical_function(name, desc, f):
@Substitution(outname=name, desc=desc)
@Appender(_index_shared_docs["index_" + name])
@Appender(_doc)
def logical_func(self, *args, **kwargs):
result = f(self.values)
if (
isinstance(result, (np.ndarray, ABCSeries, Index))
and result.ndim == 0
):
# return NumPy type
return result.dtype.type(result.item())
else: # pragma: no cover
return result
logical_func.__name__ = name
return logical_func
cls.all = _make_logical_function(
"all", "Return whether all elements are True.", np.all
)
cls.any = _make_logical_function(
"any", "Return whether any element is True.", np.any
)
@classmethod
def _add_logical_methods_disabled(cls):
"""
Add in logical methods to disable.
"""
cls.all = make_invalid_op("all")
cls.any = make_invalid_op("any")
@property
def shape(self):
"""
Return a tuple of the shape of the underlying data.
"""
# not using "(len(self), )" to return "correct" shape if the values
# consists of a >1 D array (see GH-27775)
# overridden in MultiIndex.shape to avoid materializing the values
return self._values.shape
Index._add_numeric_methods_disabled()
Index._add_logical_methods()
Index._add_comparison_methods()
def ensure_index_from_sequences(sequences, names=None):
"""
Construct an index from sequences of data.
A single sequence returns an Index. Many sequences returns a
MultiIndex.
Parameters
----------
sequences : sequence of sequences
names : sequence of str
Returns
-------
index : Index or MultiIndex
Examples
--------
>>> ensure_index_from_sequences([[1, 2, 3]], names=['name'])
Int64Index([1, 2, 3], dtype='int64', name='name')
>>> ensure_index_from_sequences([['a', 'a'], ['a', 'b']],
names=['L1', 'L2'])
MultiIndex([('a', 'a'),
('a', 'b')],
names=['L1', 'L2'])
See Also
--------
ensure_index
"""
from .multi import MultiIndex
if len(sequences) == 1:
if names is not None:
names = names[0]
return Index(sequences[0], name=names)
else:
return MultiIndex.from_arrays(sequences, names=names)
def ensure_index(index_like, copy=False):
"""
Ensure that we have an index from some index-like object.
Parameters
----------
index : sequence
An Index or other sequence
copy : bool
Returns
-------
index : Index or MultiIndex
Examples
--------
>>> ensure_index(['a', 'b'])
Index(['a', 'b'], dtype='object')
>>> ensure_index([('a', 'a'), ('b', 'c')])
Index([('a', 'a'), ('b', 'c')], dtype='object')
>>> ensure_index([['a', 'a'], ['b', 'c']])
MultiIndex([('a', 'b'),
('a', 'c')],
dtype='object')
)
See Also
--------
ensure_index_from_sequences
"""
if isinstance(index_like, Index):
if copy:
index_like = index_like.copy()
return index_like
if hasattr(index_like, "name"):
return Index(index_like, name=index_like.name, copy=copy)
if is_iterator(index_like):
index_like = list(index_like)
# must check for exactly list here because of strict type
# check in clean_index_list
if isinstance(index_like, list):
if type(index_like) != list:
index_like = list(index_like)
converted, all_arrays = lib.clean_index_list(index_like)
if len(converted) > 0 and all_arrays:
from .multi import MultiIndex
return MultiIndex.from_arrays(converted)
else:
index_like = converted
else:
# clean_index_list does the equivalent of copying
# so only need to do this if not list instance
if copy:
from copy import copy
index_like = copy(index_like)
return Index(index_like)
def _ensure_has_len(seq):
"""
If seq is an iterator, put its values into a list.
"""
try:
len(seq)
except TypeError:
return list(seq)
else:
return seq
def _trim_front(strings):
"""
Trims zeros and decimal points.
"""
trimmed = strings
while len(strings) > 0 and all(x[0] == " " for x in trimmed):
trimmed = [x[1:] for x in trimmed]
return trimmed
def _validate_join_method(method):
if method not in ["left", "right", "inner", "outer"]:
raise ValueError(f"do not recognize join method {method}")
def default_index(n):
from pandas.core.indexes.range import RangeIndex
return RangeIndex(0, n, name=None)
def maybe_extract_name(name, obj, cls) -> Optional[Hashable]:
"""
If no name is passed, then extract it from data, validating hashability.
"""
if name is None and isinstance(obj, (Index, ABCSeries)):
# Note we don't just check for "name" attribute since that would
# pick up e.g. dtype.name
name = obj.name
# GH#29069
if not is_hashable(name):
raise TypeError(f"{cls.__name__}.name must be a hashable type")
return name
def _maybe_cast_with_dtype(data: np.ndarray, dtype: np.dtype, copy: bool) -> np.ndarray:
"""
If a dtype is passed, cast to the closest matching dtype that is supported
by Index.
Parameters
----------
data : np.ndarray
dtype : np.dtype
copy : bool
Returns
-------
np.ndarray
"""
# we need to avoid having numpy coerce
# things that look like ints/floats to ints unless
# they are actually ints, e.g. '0' and 0.0
# should not be coerced
# GH 11836
if is_integer_dtype(dtype):
inferred = lib.infer_dtype(data, skipna=False)
if inferred == "integer":
data = maybe_cast_to_integer_array(data, dtype, copy=copy)
elif inferred in ["floating", "mixed-integer-float"]:
if isna(data).any():
raise ValueError("cannot convert float NaN to integer")
if inferred == "mixed-integer-float":
data = maybe_cast_to_integer_array(data, dtype)
# If we are actually all equal to integers,
# then coerce to integer.
try:
data = _try_convert_to_int_array(data, copy, dtype)
except ValueError:
data = np.array(data, dtype=np.float64, copy=copy)
elif inferred == "string":
pass
else:
data = data.astype(dtype)
elif is_float_dtype(dtype):
inferred = lib.infer_dtype(data, skipna=False)
if inferred == "string":
pass
else:
data = data.astype(dtype)
else:
data = np.array(data, dtype=dtype, copy=copy)
return data
def _maybe_cast_data_without_dtype(subarr):
"""
If we have an arraylike input but no passed dtype, try to infer
a supported dtype.
Parameters
----------
subarr : np.ndarray, Index, or Series
Returns
-------
converted : np.ndarray or ExtensionArray
dtype : np.dtype or ExtensionDtype
"""
# Runtime import needed bc IntervalArray imports Index
from pandas.core.arrays import (
IntervalArray,
PeriodArray,
DatetimeArray,
TimedeltaArray,
)
inferred = lib.infer_dtype(subarr, skipna=False)
if inferred == "integer":
try:
data = _try_convert_to_int_array(subarr, False, None)
return data, data.dtype
except ValueError:
pass
return subarr, object
elif inferred in ["floating", "mixed-integer-float", "integer-na"]:
# TODO: Returns IntegerArray for integer-na case in the future
return subarr, np.float64
elif inferred == "interval":
try:
data = IntervalArray._from_sequence(subarr, copy=False)
return data, data.dtype
except ValueError:
# GH27172: mixed closed Intervals --> object dtype
pass
elif inferred == "boolean":
# don't support boolean explicitly ATM
pass
elif inferred != "string":
if inferred.startswith("datetime"):
try:
data = DatetimeArray._from_sequence(subarr, copy=False)
return data, data.dtype
except (ValueError, OutOfBoundsDatetime):
# GH 27011
# If we have mixed timezones, just send it
# down the base constructor
pass
elif inferred.startswith("timedelta"):
data = TimedeltaArray._from_sequence(subarr, copy=False)
return data, data.dtype
elif inferred == "period":
try:
data = PeriodArray._from_sequence(subarr)
return data, data.dtype
except IncompatibleFrequency:
pass
return subarr, subarr.dtype
def _try_convert_to_int_array(
data: np.ndarray, copy: bool, dtype: np.dtype
) -> np.ndarray:
"""
Attempt to convert an array of data into an integer array.
Parameters
----------
data : The data to convert.
copy : bool
Whether to copy the data or not.
dtype : np.dtype
Returns
-------
int_array : data converted to either an ndarray[int64] or ndarray[uint64]
Raises
------
ValueError if the conversion was not successful.
"""
if not is_unsigned_integer_dtype(dtype):
# skip int64 conversion attempt if uint-like dtype is passed, as
# this could return Int64Index when UInt64Index is what's desired
try:
res = data.astype("i8", copy=False)
if (res == data).all():
return res # TODO: might still need to copy
except (OverflowError, TypeError, ValueError):
pass
# Conversion to int64 failed (possibly due to overflow) or was skipped,
# so let's try now with uint64.
try:
res = data.astype("u8", copy=False)
if (res == data).all():
return res # TODO: might still need to copy
except (OverflowError, TypeError, ValueError):
pass
raise ValueError
| BugsInPy/BugsInPy/temp/projects/pandas/bug-98-fixed/pandas/pandas/core/indexes/base.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-98-buggy/pandas/pandas/core/indexes/base.py |
pandas-bug-57 | import bz2
from collections import Counter
from contextlib import contextmanager
from datetime import datetime
from functools import wraps
import gzip
import os
from shutil import rmtree
import string
import tempfile
from typing import Any, Callable, List, Optional, Type, Union, cast
import warnings
import zipfile
import numpy as np
from numpy.random import rand, randn
from pandas._config.localization import ( # noqa:F401
can_set_locale,
get_locales,
set_locale,
)
import pandas._libs.testing as _testing
from pandas._typing import FilePathOrBuffer, FrameOrSeries
from pandas.compat import _get_lzma_file, _import_lzma
from pandas.core.dtypes.common import (
is_bool,
is_categorical_dtype,
is_datetime64_dtype,
is_datetime64tz_dtype,
is_extension_array_dtype,
is_interval_dtype,
is_list_like,
is_number,
is_period_dtype,
is_sequence,
is_timedelta64_dtype,
needs_i8_conversion,
)
from pandas.core.dtypes.missing import array_equivalent
import pandas as pd
from pandas import (
Categorical,
CategoricalIndex,
DataFrame,
DatetimeIndex,
Index,
IntervalIndex,
MultiIndex,
RangeIndex,
Series,
bdate_range,
)
from pandas.core.algorithms import take_1d
from pandas.core.arrays import (
DatetimeArray,
ExtensionArray,
IntervalArray,
PeriodArray,
TimedeltaArray,
period_array,
)
from pandas.io.common import urlopen
from pandas.io.formats.printing import pprint_thing
lzma = _import_lzma()
N = 30
K = 4
_RAISE_NETWORK_ERROR_DEFAULT = False
# set testing_mode
_testing_mode_warnings = (DeprecationWarning, ResourceWarning)
def set_testing_mode():
# set the testing mode filters
testing_mode = os.environ.get("PANDAS_TESTING_MODE", "None")
if "deprecate" in testing_mode:
warnings.simplefilter("always", _testing_mode_warnings)
def reset_testing_mode():
# reset the testing mode filters
testing_mode = os.environ.get("PANDAS_TESTING_MODE", "None")
if "deprecate" in testing_mode:
warnings.simplefilter("ignore", _testing_mode_warnings)
set_testing_mode()
def reset_display_options():
"""
Reset the display options for printing and representing objects.
"""
pd.reset_option("^display.", silent=True)
def round_trip_pickle(
obj: Any, path: Optional[FilePathOrBuffer] = None
) -> FrameOrSeries:
"""
Pickle an object and then read it again.
Parameters
----------
obj : any object
The object to pickle and then re-read.
path : str, path object or file-like object, default None
The path where the pickled object is written and then read.
Returns
-------
pandas object
The original object that was pickled and then re-read.
"""
_path = path
if _path is None:
_path = f"__{rands(10)}__.pickle"
with ensure_clean(_path) as temp_path:
pd.to_pickle(obj, temp_path)
return pd.read_pickle(temp_path)
def round_trip_pathlib(writer, reader, path: Optional[str] = None):
"""
Write an object to file specified by a pathlib.Path and read it back
Parameters
----------
writer : callable bound to pandas object
IO writing function (e.g. DataFrame.to_csv )
reader : callable
IO reading function (e.g. pd.read_csv )
path : str, default None
The path where the object is written and then read.
Returns
-------
pandas object
The original object that was serialized and then re-read.
"""
import pytest
Path = pytest.importorskip("pathlib").Path
if path is None:
path = "___pathlib___"
with ensure_clean(path) as path:
writer(Path(path))
obj = reader(Path(path))
return obj
def round_trip_localpath(writer, reader, path: Optional[str] = None):
"""
Write an object to file specified by a py.path LocalPath and read it back.
Parameters
----------
writer : callable bound to pandas object
IO writing function (e.g. DataFrame.to_csv )
reader : callable
IO reading function (e.g. pd.read_csv )
path : str, default None
The path where the object is written and then read.
Returns
-------
pandas object
The original object that was serialized and then re-read.
"""
import pytest
LocalPath = pytest.importorskip("py.path").local
if path is None:
path = "___localpath___"
with ensure_clean(path) as path:
writer(LocalPath(path))
obj = reader(LocalPath(path))
return obj
@contextmanager
def decompress_file(path, compression):
"""
Open a compressed file and return a file object.
Parameters
----------
path : str
The path where the file is read from.
compression : {'gzip', 'bz2', 'zip', 'xz', None}
Name of the decompression to use
Returns
-------
file object
"""
if compression is None:
f = open(path, "rb")
elif compression == "gzip":
f = gzip.open(path, "rb")
elif compression == "bz2":
f = bz2.BZ2File(path, "rb")
elif compression == "xz":
f = _get_lzma_file(lzma)(path, "rb")
elif compression == "zip":
zip_file = zipfile.ZipFile(path)
zip_names = zip_file.namelist()
if len(zip_names) == 1:
f = zip_file.open(zip_names.pop())
else:
raise ValueError(f"ZIP file {path} error. Only one file per ZIP.")
else:
raise ValueError(f"Unrecognized compression type: {compression}")
try:
yield f
finally:
f.close()
if compression == "zip":
zip_file.close()
def write_to_compressed(compression, path, data, dest="test"):
"""
Write data to a compressed file.
Parameters
----------
compression : {'gzip', 'bz2', 'zip', 'xz'}
The compression type to use.
path : str
The file path to write the data.
data : str
The data to write.
dest : str, default "test"
The destination file (for ZIP only)
Raises
------
ValueError : An invalid compression value was passed in.
"""
if compression == "zip":
import zipfile
compress_method = zipfile.ZipFile
elif compression == "gzip":
import gzip
compress_method = gzip.GzipFile
elif compression == "bz2":
import bz2
compress_method = bz2.BZ2File
elif compression == "xz":
compress_method = _get_lzma_file(lzma)
else:
raise ValueError(f"Unrecognized compression type: {compression}")
if compression == "zip":
mode = "w"
args = (dest, data)
method = "writestr"
else:
mode = "wb"
args = (data,)
method = "write"
with compress_method(path, mode=mode) as f:
getattr(f, method)(*args)
def assert_almost_equal(
left,
right,
check_dtype: Union[bool, str] = "equiv",
check_less_precise: Union[bool, int] = False,
**kwargs,
):
"""
Check that the left and right objects are approximately equal.
By approximately equal, we refer to objects that are numbers or that
contain numbers which may be equivalent to specific levels of precision.
Parameters
----------
left : object
right : object
check_dtype : bool or {'equiv'}, default 'equiv'
Check dtype if both a and b are the same type. If 'equiv' is passed in,
then `RangeIndex` and `Int64Index` are also considered equivalent
when doing type checking.
check_less_precise : bool or int, default False
Specify comparison precision. 5 digits (False) or 3 digits (True)
after decimal points are compared. If int, then specify the number
of digits to compare.
When comparing two numbers, if the first number has magnitude less
than 1e-5, we compare the two numbers directly and check whether
they are equivalent within the specified precision. Otherwise, we
compare the **ratio** of the second number to the first number and
check whether it is equivalent to 1 within the specified precision.
"""
if isinstance(left, pd.Index):
assert_index_equal(
left,
right,
check_exact=False,
exact=check_dtype,
check_less_precise=check_less_precise,
**kwargs,
)
elif isinstance(left, pd.Series):
assert_series_equal(
left,
right,
check_exact=False,
check_dtype=check_dtype,
check_less_precise=check_less_precise,
**kwargs,
)
elif isinstance(left, pd.DataFrame):
assert_frame_equal(
left,
right,
check_exact=False,
check_dtype=check_dtype,
check_less_precise=check_less_precise,
**kwargs,
)
else:
# Other sequences.
if check_dtype:
if is_number(left) and is_number(right):
# Do not compare numeric classes, like np.float64 and float.
pass
elif is_bool(left) and is_bool(right):
# Do not compare bool classes, like np.bool_ and bool.
pass
else:
if isinstance(left, np.ndarray) or isinstance(right, np.ndarray):
obj = "numpy array"
else:
obj = "Input"
assert_class_equal(left, right, obj=obj)
_testing.assert_almost_equal(
left,
right,
check_dtype=check_dtype,
check_less_precise=check_less_precise,
**kwargs,
)
def _check_isinstance(left, right, cls):
"""
Helper method for our assert_* methods that ensures that
the two objects being compared have the right type before
proceeding with the comparison.
Parameters
----------
left : The first object being compared.
right : The second object being compared.
cls : The class type to check against.
Raises
------
AssertionError : Either `left` or `right` is not an instance of `cls`.
"""
cls_name = cls.__name__
if not isinstance(left, cls):
raise AssertionError(
f"{cls_name} Expected type {cls}, found {type(left)} instead"
)
if not isinstance(right, cls):
raise AssertionError(
f"{cls_name} Expected type {cls}, found {type(right)} instead"
)
def assert_dict_equal(left, right, compare_keys: bool = True):
_check_isinstance(left, right, dict)
_testing.assert_dict_equal(left, right, compare_keys=compare_keys)
def randbool(size=(), p: float = 0.5):
return rand(*size) <= p
RANDS_CHARS = np.array(list(string.ascii_letters + string.digits), dtype=(np.str_, 1))
RANDU_CHARS = np.array(
list("".join(map(chr, range(1488, 1488 + 26))) + string.digits),
dtype=(np.unicode_, 1),
)
def rands_array(nchars, size, dtype="O"):
"""
Generate an array of byte strings.
"""
retval = (
np.random.choice(RANDS_CHARS, size=nchars * np.prod(size))
.view((np.str_, nchars))
.reshape(size)
)
if dtype is None:
return retval
else:
return retval.astype(dtype)
def randu_array(nchars, size, dtype="O"):
"""
Generate an array of unicode strings.
"""
retval = (
np.random.choice(RANDU_CHARS, size=nchars * np.prod(size))
.view((np.unicode_, nchars))
.reshape(size)
)
if dtype is None:
return retval
else:
return retval.astype(dtype)
def rands(nchars):
"""
Generate one random byte string.
See `rands_array` if you want to create an array of random strings.
"""
return "".join(np.random.choice(RANDS_CHARS, nchars))
def randu(nchars):
"""
Generate one random unicode string.
See `randu_array` if you want to create an array of random unicode strings.
"""
return "".join(np.random.choice(RANDU_CHARS, nchars))
def close(fignum=None):
from matplotlib.pyplot import get_fignums, close as _close
if fignum is None:
for fignum in get_fignums():
_close(fignum)
else:
_close(fignum)
# -----------------------------------------------------------------------------
# contextmanager to ensure the file cleanup
@contextmanager
def ensure_clean(filename=None, return_filelike=False, **kwargs):
"""
Gets a temporary path and agrees to remove on close.
Parameters
----------
filename : str (optional)
if None, creates a temporary file which is then removed when out of
scope. if passed, creates temporary file with filename as ending.
return_filelike : bool (default False)
if True, returns a file-like which is *always* cleaned. Necessary for
savefig and other functions which want to append extensions.
**kwargs
Additional keywords passed in for creating a temporary file.
:meth:`tempFile.TemporaryFile` is used when `return_filelike` is ``True``.
:meth:`tempfile.mkstemp` is used when `return_filelike` is ``False``.
Note that the `filename` parameter will be passed in as the `suffix`
argument to either function.
See Also
--------
tempfile.TemporaryFile
tempfile.mkstemp
"""
filename = filename or ""
fd = None
kwargs["suffix"] = filename
if return_filelike:
f = tempfile.TemporaryFile(**kwargs)
try:
yield f
finally:
f.close()
else:
# Don't generate tempfile if using a path with directory specified.
if len(os.path.dirname(filename)):
raise ValueError("Can't pass a qualified name to ensure_clean()")
try:
fd, filename = tempfile.mkstemp(**kwargs)
except UnicodeEncodeError:
import pytest
pytest.skip("no unicode file names on this system")
try:
yield filename
finally:
try:
os.close(fd)
except OSError:
print(f"Couldn't close file descriptor: {fd} (file: {filename})")
try:
if os.path.exists(filename):
os.remove(filename)
except OSError as e:
print(f"Exception on removing file: {e}")
@contextmanager
def ensure_clean_dir():
"""
Get a temporary directory path and agrees to remove on close.
Yields
------
Temporary directory path
"""
directory_name = tempfile.mkdtemp(suffix="")
try:
yield directory_name
finally:
try:
rmtree(directory_name)
except OSError:
pass
@contextmanager
def ensure_safe_environment_variables():
"""
Get a context manager to safely set environment variables
All changes will be undone on close, hence environment variables set
within this contextmanager will neither persist nor change global state.
"""
saved_environ = dict(os.environ)
try:
yield
finally:
os.environ.clear()
os.environ.update(saved_environ)
# -----------------------------------------------------------------------------
# Comparators
def equalContents(arr1, arr2) -> bool:
"""
Checks if the set of unique elements of arr1 and arr2 are equivalent.
"""
return frozenset(arr1) == frozenset(arr2)
def assert_index_equal(
left: Index,
right: Index,
exact: Union[bool, str] = "equiv",
check_names: bool = True,
check_less_precise: Union[bool, int] = False,
check_exact: bool = True,
check_categorical: bool = True,
obj: str = "Index",
) -> None:
"""
Check that left and right Index are equal.
Parameters
----------
left : Index
right : Index
exact : bool or {'equiv'}, default 'equiv'
Whether to check the Index class, dtype and inferred_type
are identical. If 'equiv', then RangeIndex can be substituted for
Int64Index as well.
check_names : bool, default True
Whether to check the names attribute.
check_less_precise : bool or int, default False
Specify comparison precision. Only used when check_exact is False.
5 digits (False) or 3 digits (True) after decimal points are compared.
If int, then specify the digits to compare.
check_exact : bool, default True
Whether to compare number exactly.
check_categorical : bool, default True
Whether to compare internal Categorical exactly.
obj : str, default 'Index'
Specify object name being compared, internally used to show appropriate
assertion message.
"""
__tracebackhide__ = True
def _check_types(l, r, obj="Index"):
if exact:
assert_class_equal(l, r, exact=exact, obj=obj)
# Skip exact dtype checking when `check_categorical` is False
if check_categorical:
assert_attr_equal("dtype", l, r, obj=obj)
# allow string-like to have different inferred_types
if l.inferred_type in ("string"):
assert r.inferred_type in ("string")
else:
assert_attr_equal("inferred_type", l, r, obj=obj)
def _get_ilevel_values(index, level):
# accept level number only
unique = index.levels[level]
level_codes = index.codes[level]
filled = take_1d(unique._values, level_codes, fill_value=unique._na_value)
values = unique._shallow_copy(filled, name=index.names[level])
return values
# instance validation
_check_isinstance(left, right, Index)
# class / dtype comparison
_check_types(left, right, obj=obj)
# level comparison
if left.nlevels != right.nlevels:
msg1 = f"{obj} levels are different"
msg2 = f"{left.nlevels}, {left}"
msg3 = f"{right.nlevels}, {right}"
raise_assert_detail(obj, msg1, msg2, msg3)
# length comparison
if len(left) != len(right):
msg1 = f"{obj} length are different"
msg2 = f"{len(left)}, {left}"
msg3 = f"{len(right)}, {right}"
raise_assert_detail(obj, msg1, msg2, msg3)
# MultiIndex special comparison for little-friendly error messages
if left.nlevels > 1:
left = cast(MultiIndex, left)
right = cast(MultiIndex, right)
for level in range(left.nlevels):
# cannot use get_level_values here because it can change dtype
llevel = _get_ilevel_values(left, level)
rlevel = _get_ilevel_values(right, level)
lobj = f"MultiIndex level [{level}]"
assert_index_equal(
llevel,
rlevel,
exact=exact,
check_names=check_names,
check_less_precise=check_less_precise,
check_exact=check_exact,
obj=lobj,
)
# get_level_values may change dtype
_check_types(left.levels[level], right.levels[level], obj=obj)
# skip exact index checking when `check_categorical` is False
if check_exact and check_categorical:
if not left.equals(right):
diff = np.sum((left.values != right.values).astype(int)) * 100.0 / len(left)
msg = f"{obj} values are different ({np.round(diff, 5)} %)"
raise_assert_detail(obj, msg, left, right)
else:
_testing.assert_almost_equal(
left.values,
right.values,
check_less_precise=check_less_precise,
check_dtype=exact,
obj=obj,
lobj=left,
robj=right,
)
# metadata comparison
if check_names:
assert_attr_equal("names", left, right, obj=obj)
if isinstance(left, pd.PeriodIndex) or isinstance(right, pd.PeriodIndex):
assert_attr_equal("freq", left, right, obj=obj)
if isinstance(left, pd.IntervalIndex) or isinstance(right, pd.IntervalIndex):
assert_interval_array_equal(left.values, right.values)
if check_categorical:
if is_categorical_dtype(left) or is_categorical_dtype(right):
assert_categorical_equal(left.values, right.values, obj=f"{obj} category")
def assert_class_equal(left, right, exact: Union[bool, str] = True, obj="Input"):
"""
Checks classes are equal.
"""
__tracebackhide__ = True
def repr_class(x):
if isinstance(x, Index):
# return Index as it is to include values in the error message
return x
try:
return type(x).__name__
except AttributeError:
return repr(type(x))
if exact == "equiv":
if type(left) != type(right):
# allow equivalence of Int64Index/RangeIndex
types = {type(left).__name__, type(right).__name__}
if len(types - {"Int64Index", "RangeIndex"}):
msg = f"{obj} classes are not equivalent"
raise_assert_detail(obj, msg, repr_class(left), repr_class(right))
elif exact:
if type(left) != type(right):
msg = f"{obj} classes are different"
raise_assert_detail(obj, msg, repr_class(left), repr_class(right))
def assert_attr_equal(attr, left, right, obj="Attributes"):
"""
checks attributes are equal. Both objects must have attribute.
Parameters
----------
attr : str
Attribute name being compared.
left : object
right : object
obj : str, default 'Attributes'
Specify object name being compared, internally used to show appropriate
assertion message
"""
__tracebackhide__ = True
left_attr = getattr(left, attr)
right_attr = getattr(right, attr)
if left_attr is right_attr:
return True
elif (
is_number(left_attr)
and np.isnan(left_attr)
and is_number(right_attr)
and np.isnan(right_attr)
):
# np.nan
return True
try:
result = left_attr == right_attr
except TypeError:
# datetimetz on rhs may raise TypeError
result = False
if not isinstance(result, bool):
result = result.all()
if result:
return True
else:
msg = f'Attribute "{attr}" are different'
raise_assert_detail(obj, msg, left_attr, right_attr)
def assert_is_valid_plot_return_object(objs):
import matplotlib.pyplot as plt
if isinstance(objs, (pd.Series, np.ndarray)):
for el in objs.ravel():
msg = (
"one of 'objs' is not a matplotlib Axes instance, "
f"type encountered {repr(type(el).__name__)}"
)
assert isinstance(el, (plt.Axes, dict)), msg
else:
msg = (
"objs is neither an ndarray of Artist instances nor a single "
"ArtistArtist instance, tuple, or dict, 'objs' is a "
f"{repr(type(objs).__name__)}"
)
assert isinstance(objs, (plt.Artist, tuple, dict)), msg
def isiterable(obj):
return hasattr(obj, "__iter__")
def assert_is_sorted(seq):
"""Assert that the sequence is sorted."""
if isinstance(seq, (Index, Series)):
seq = seq.values
# sorting does not change precisions
assert_numpy_array_equal(seq, np.sort(np.array(seq)))
def assert_categorical_equal(
left, right, check_dtype=True, check_category_order=True, obj="Categorical"
):
"""
Test that Categoricals are equivalent.
Parameters
----------
left : Categorical
right : Categorical
check_dtype : bool, default True
Check that integer dtype of the codes are the same
check_category_order : bool, default True
Whether the order of the categories should be compared, which
implies identical integer codes. If False, only the resulting
values are compared. The ordered attribute is
checked regardless.
obj : str, default 'Categorical'
Specify object name being compared, internally used to show appropriate
assertion message
"""
_check_isinstance(left, right, Categorical)
if check_category_order:
assert_index_equal(left.categories, right.categories, obj=f"{obj}.categories")
assert_numpy_array_equal(
left.codes, right.codes, check_dtype=check_dtype, obj=f"{obj}.codes",
)
else:
assert_index_equal(
left.categories.sort_values(),
right.categories.sort_values(),
obj=f"{obj}.categories",
)
assert_index_equal(
left.categories.take(left.codes),
right.categories.take(right.codes),
obj=f"{obj}.values",
)
assert_attr_equal("ordered", left, right, obj=obj)
def assert_interval_array_equal(left, right, exact="equiv", obj="IntervalArray"):
"""
Test that two IntervalArrays are equivalent.
Parameters
----------
left, right : IntervalArray
The IntervalArrays to compare.
exact : bool or {'equiv'}, default 'equiv'
Whether to check the Index class, dtype and inferred_type
are identical. If 'equiv', then RangeIndex can be substituted for
Int64Index as well.
obj : str, default 'IntervalArray'
Specify object name being compared, internally used to show appropriate
assertion message
"""
_check_isinstance(left, right, IntervalArray)
assert_index_equal(left.left, right.left, exact=exact, obj=f"{obj}.left")
assert_index_equal(left.right, right.right, exact=exact, obj=f"{obj}.left")
assert_attr_equal("closed", left, right, obj=obj)
def assert_period_array_equal(left, right, obj="PeriodArray"):
_check_isinstance(left, right, PeriodArray)
assert_numpy_array_equal(left._data, right._data, obj=f"{obj}.values")
assert_attr_equal("freq", left, right, obj=obj)
def assert_datetime_array_equal(left, right, obj="DatetimeArray"):
__tracebackhide__ = True
_check_isinstance(left, right, DatetimeArray)
assert_numpy_array_equal(left._data, right._data, obj=f"{obj}._data")
assert_attr_equal("freq", left, right, obj=obj)
assert_attr_equal("tz", left, right, obj=obj)
def assert_timedelta_array_equal(left, right, obj="TimedeltaArray"):
__tracebackhide__ = True
_check_isinstance(left, right, TimedeltaArray)
assert_numpy_array_equal(left._data, right._data, obj=f"{obj}._data")
assert_attr_equal("freq", left, right, obj=obj)
def raise_assert_detail(obj, message, left, right, diff=None):
__tracebackhide__ = True
if isinstance(left, np.ndarray):
left = pprint_thing(left)
elif is_categorical_dtype(left):
left = repr(left)
if isinstance(right, np.ndarray):
right = pprint_thing(right)
elif is_categorical_dtype(right):
right = repr(right)
msg = f"""{obj} are different
{message}
[left]: {left}
[right]: {right}"""
if diff is not None:
msg += f"\n[diff]: {diff}"
raise AssertionError(msg)
def assert_numpy_array_equal(
left,
right,
strict_nan=False,
check_dtype=True,
err_msg=None,
check_same=None,
obj="numpy array",
):
"""
Check that 'np.ndarray' is equivalent.
Parameters
----------
left, right : numpy.ndarray or iterable
The two arrays to be compared.
strict_nan : bool, default False
If True, consider NaN and None to be different.
check_dtype : bool, default True
Check dtype if both a and b are np.ndarray.
err_msg : str, default None
If provided, used as assertion message.
check_same : None|'copy'|'same', default None
Ensure left and right refer/do not refer to the same memory area.
obj : str, default 'numpy array'
Specify object name being compared, internally used to show appropriate
assertion message.
"""
__tracebackhide__ = True
# instance validation
# Show a detailed error message when classes are different
assert_class_equal(left, right, obj=obj)
# both classes must be an np.ndarray
_check_isinstance(left, right, np.ndarray)
def _get_base(obj):
return obj.base if getattr(obj, "base", None) is not None else obj
left_base = _get_base(left)
right_base = _get_base(right)
if check_same == "same":
if left_base is not right_base:
raise AssertionError(f"{repr(left_base)} is not {repr(right_base)}")
elif check_same == "copy":
if left_base is right_base:
raise AssertionError(f"{repr(left_base)} is {repr(right_base)}")
def _raise(left, right, err_msg):
if err_msg is None:
if left.shape != right.shape:
raise_assert_detail(
obj, f"{obj} shapes are different", left.shape, right.shape,
)
diff = 0
for l, r in zip(left, right):
# count up differences
if not array_equivalent(l, r, strict_nan=strict_nan):
diff += 1
diff = diff * 100.0 / left.size
msg = f"{obj} values are different ({np.round(diff, 5)} %)"
raise_assert_detail(obj, msg, left, right)
raise AssertionError(err_msg)
# compare shape and values
if not array_equivalent(left, right, strict_nan=strict_nan):
_raise(left, right, err_msg)
if check_dtype:
if isinstance(left, np.ndarray) and isinstance(right, np.ndarray):
assert_attr_equal("dtype", left, right, obj=obj)
def assert_extension_array_equal(
left, right, check_dtype=True, check_less_precise=False, check_exact=False
):
"""
Check that left and right ExtensionArrays are equal.
Parameters
----------
left, right : ExtensionArray
The two arrays to compare.
check_dtype : bool, default True
Whether to check if the ExtensionArray dtypes are identical.
check_less_precise : bool or int, default False
Specify comparison precision. Only used when check_exact is False.
5 digits (False) or 3 digits (True) after decimal points are compared.
If int, then specify the digits to compare.
check_exact : bool, default False
Whether to compare number exactly.
Notes
-----
Missing values are checked separately from valid values.
A mask of missing values is computed for each and checked to match.
The remaining all-valid values are cast to object dtype and checked.
"""
assert isinstance(left, ExtensionArray), "left is not an ExtensionArray"
assert isinstance(right, ExtensionArray), "right is not an ExtensionArray"
if check_dtype:
assert_attr_equal("dtype", left, right, obj="ExtensionArray")
if hasattr(left, "asi8") and type(right) == type(left):
# Avoid slow object-dtype comparisons
assert_numpy_array_equal(left.asi8, right.asi8)
return
left_na = np.asarray(left.isna())
right_na = np.asarray(right.isna())
assert_numpy_array_equal(left_na, right_na, obj="ExtensionArray NA mask")
left_valid = np.asarray(left[~left_na].astype(object))
right_valid = np.asarray(right[~right_na].astype(object))
if check_exact:
assert_numpy_array_equal(left_valid, right_valid, obj="ExtensionArray")
else:
_testing.assert_almost_equal(
left_valid,
right_valid,
check_dtype=check_dtype,
check_less_precise=check_less_precise,
obj="ExtensionArray",
)
# This could be refactored to use the NDFrame.equals method
def assert_series_equal(
left,
right,
check_dtype=True,
check_index_type="equiv",
check_series_type=True,
check_less_precise=False,
check_names=True,
check_exact=False,
check_datetimelike_compat=False,
check_categorical=True,
obj="Series",
):
"""
Check that left and right Series are equal.
Parameters
----------
left : Series
right : Series
check_dtype : bool, default True
Whether to check the Series dtype is identical.
check_index_type : bool or {'equiv'}, default 'equiv'
Whether to check the Index class, dtype and inferred_type
are identical.
check_series_type : bool, default True
Whether to check the Series class is identical.
check_less_precise : bool or int, default False
Specify comparison precision. Only used when check_exact is False.
5 digits (False) or 3 digits (True) after decimal points are compared.
If int, then specify the digits to compare.
When comparing two numbers, if the first number has magnitude less
than 1e-5, we compare the two numbers directly and check whether
they are equivalent within the specified precision. Otherwise, we
compare the **ratio** of the second number to the first number and
check whether it is equivalent to 1 within the specified precision.
check_names : bool, default True
Whether to check the Series and Index names attribute.
check_exact : bool, default False
Whether to compare number exactly.
check_datetimelike_compat : bool, default False
Compare datetime-like which is comparable ignoring dtype.
check_categorical : bool, default True
Whether to compare internal Categorical exactly.
obj : str, default 'Series'
Specify object name being compared, internally used to show appropriate
assertion message.
"""
__tracebackhide__ = True
# instance validation
_check_isinstance(left, right, Series)
if check_series_type:
# ToDo: There are some tests using rhs is sparse
# lhs is dense. Should use assert_class_equal in future
assert isinstance(left, type(right))
# assert_class_equal(left, right, obj=obj)
# length comparison
if len(left) != len(right):
msg1 = f"{len(left)}, {left.index}"
msg2 = f"{len(right)}, {right.index}"
raise_assert_detail(obj, "Series length are different", msg1, msg2)
# index comparison
assert_index_equal(
left.index,
right.index,
exact=check_index_type,
check_names=check_names,
check_less_precise=check_less_precise,
check_exact=check_exact,
check_categorical=check_categorical,
obj=f"{obj}.index",
)
if check_dtype:
# We want to skip exact dtype checking when `check_categorical`
# is False. We'll still raise if only one is a `Categorical`,
# regardless of `check_categorical`
if (
is_categorical_dtype(left)
and is_categorical_dtype(right)
and not check_categorical
):
pass
else:
assert_attr_equal("dtype", left, right, obj=f"Attributes of {obj}")
if check_exact:
assert_numpy_array_equal(
left._internal_get_values(),
right._internal_get_values(),
check_dtype=check_dtype,
obj=str(obj),
)
elif check_datetimelike_compat:
# we want to check only if we have compat dtypes
# e.g. integer and M|m are NOT compat, but we can simply check
# the values in that case
if needs_i8_conversion(left) or needs_i8_conversion(right):
# datetimelike may have different objects (e.g. datetime.datetime
# vs Timestamp) but will compare equal
if not Index(left.values).equals(Index(right.values)):
msg = (
f"[datetimelike_compat=True] {left.values} "
f"is not equal to {right.values}."
)
raise AssertionError(msg)
else:
assert_numpy_array_equal(
left._internal_get_values(),
right._internal_get_values(),
check_dtype=check_dtype,
)
elif is_interval_dtype(left) or is_interval_dtype(right):
assert_interval_array_equal(left.array, right.array)
elif is_extension_array_dtype(left.dtype) and is_datetime64tz_dtype(left.dtype):
# .values is an ndarray, but ._values is the ExtensionArray.
# TODO: Use .array
assert is_extension_array_dtype(right.dtype)
assert_extension_array_equal(left._values, right._values)
elif (
is_extension_array_dtype(left)
and not is_categorical_dtype(left)
and is_extension_array_dtype(right)
and not is_categorical_dtype(right)
):
assert_extension_array_equal(left.array, right.array)
else:
_testing.assert_almost_equal(
left._internal_get_values(),
right._internal_get_values(),
check_less_precise=check_less_precise,
check_dtype=check_dtype,
obj=str(obj),
)
# metadata comparison
if check_names:
assert_attr_equal("name", left, right, obj=obj)
if check_categorical:
if is_categorical_dtype(left) or is_categorical_dtype(right):
assert_categorical_equal(left.values, right.values, obj=f"{obj} category")
# This could be refactored to use the NDFrame.equals method
def assert_frame_equal(
left,
right,
check_dtype=True,
check_index_type="equiv",
check_column_type="equiv",
check_frame_type=True,
check_less_precise=False,
check_names=True,
by_blocks=False,
check_exact=False,
check_datetimelike_compat=False,
check_categorical=True,
check_like=False,
obj="DataFrame",
):
"""
Check that left and right DataFrame are equal.
This function is intended to compare two DataFrames and output any
differences. Is is mostly intended for use in unit tests.
Additional parameters allow varying the strictness of the
equality checks performed.
Parameters
----------
left : DataFrame
First DataFrame to compare.
right : DataFrame
Second DataFrame to compare.
check_dtype : bool, default True
Whether to check the DataFrame dtype is identical.
check_index_type : bool or {'equiv'}, default 'equiv'
Whether to check the Index class, dtype and inferred_type
are identical.
check_column_type : bool or {'equiv'}, default 'equiv'
Whether to check the columns class, dtype and inferred_type
are identical. Is passed as the ``exact`` argument of
:func:`assert_index_equal`.
check_frame_type : bool, default True
Whether to check the DataFrame class is identical.
check_less_precise : bool or int, default False
Specify comparison precision. Only used when check_exact is False.
5 digits (False) or 3 digits (True) after decimal points are compared.
If int, then specify the digits to compare.
When comparing two numbers, if the first number has magnitude less
than 1e-5, we compare the two numbers directly and check whether
they are equivalent within the specified precision. Otherwise, we
compare the **ratio** of the second number to the first number and
check whether it is equivalent to 1 within the specified precision.
check_names : bool, default True
Whether to check that the `names` attribute for both the `index`
and `column` attributes of the DataFrame is identical.
by_blocks : bool, default False
Specify how to compare internal data. If False, compare by columns.
If True, compare by blocks.
check_exact : bool, default False
Whether to compare number exactly.
check_datetimelike_compat : bool, default False
Compare datetime-like which is comparable ignoring dtype.
check_categorical : bool, default True
Whether to compare internal Categorical exactly.
check_like : bool, default False
If True, ignore the order of index & columns.
Note: index labels must match their respective rows
(same as in columns) - same labels must be with the same data.
obj : str, default 'DataFrame'
Specify object name being compared, internally used to show appropriate
assertion message.
See Also
--------
assert_series_equal : Equivalent method for asserting Series equality.
DataFrame.equals : Check DataFrame equality.
Examples
--------
This example shows comparing two DataFrames that are equal
but with columns of differing dtypes.
>>> from pandas._testing import assert_frame_equal
>>> df1 = pd.DataFrame({'a': [1, 2], 'b': [3, 4]})
>>> df2 = pd.DataFrame({'a': [1, 2], 'b': [3.0, 4.0]})
df1 equals itself.
>>> assert_frame_equal(df1, df1)
df1 differs from df2 as column 'b' is of a different type.
>>> assert_frame_equal(df1, df2)
Traceback (most recent call last):
...
AssertionError: Attributes of DataFrame.iloc[:, 1] (column name="b") are different
Attribute "dtype" are different
[left]: int64
[right]: float64
Ignore differing dtypes in columns with check_dtype.
>>> assert_frame_equal(df1, df2, check_dtype=False)
"""
__tracebackhide__ = True
# instance validation
_check_isinstance(left, right, DataFrame)
if check_frame_type:
assert isinstance(left, type(right))
# assert_class_equal(left, right, obj=obj)
# shape comparison
if left.shape != right.shape:
raise_assert_detail(
obj, f"{obj} shape mismatch", f"{repr(left.shape)}", f"{repr(right.shape)}",
)
if check_like:
left, right = left.reindex_like(right), right
# index comparison
assert_index_equal(
left.index,
right.index,
exact=check_index_type,
check_names=check_names,
check_less_precise=check_less_precise,
check_exact=check_exact,
check_categorical=check_categorical,
obj=f"{obj}.index",
)
# column comparison
assert_index_equal(
left.columns,
right.columns,
exact=check_column_type,
check_names=check_names,
check_less_precise=check_less_precise,
check_exact=check_exact,
check_categorical=check_categorical,
obj=f"{obj}.columns",
)
# compare by blocks
if by_blocks:
rblocks = right._to_dict_of_blocks()
lblocks = left._to_dict_of_blocks()
for dtype in list(set(list(lblocks.keys()) + list(rblocks.keys()))):
assert dtype in lblocks
assert dtype in rblocks
assert_frame_equal(
lblocks[dtype], rblocks[dtype], check_dtype=check_dtype, obj=obj
)
# compare by columns
else:
for i, col in enumerate(left.columns):
assert col in right
lcol = left.iloc[:, i]
rcol = right.iloc[:, i]
assert_series_equal(
lcol,
rcol,
check_dtype=check_dtype,
check_index_type=check_index_type,
check_less_precise=check_less_precise,
check_exact=check_exact,
check_names=check_names,
check_datetimelike_compat=check_datetimelike_compat,
check_categorical=check_categorical,
obj=f'{obj}.iloc[:, {i}] (column name="{col}")',
)
def assert_equal(left, right, **kwargs):
"""
Wrapper for tm.assert_*_equal to dispatch to the appropriate test function.
Parameters
----------
left, right : Index, Series, DataFrame, ExtensionArray, or np.ndarray
The two items to be compared.
**kwargs
All keyword arguments are passed through to the underlying assert method.
"""
__tracebackhide__ = True
if isinstance(left, pd.Index):
assert_index_equal(left, right, **kwargs)
elif isinstance(left, pd.Series):
assert_series_equal(left, right, **kwargs)
elif isinstance(left, pd.DataFrame):
assert_frame_equal(left, right, **kwargs)
elif isinstance(left, IntervalArray):
assert_interval_array_equal(left, right, **kwargs)
elif isinstance(left, PeriodArray):
assert_period_array_equal(left, right, **kwargs)
elif isinstance(left, DatetimeArray):
assert_datetime_array_equal(left, right, **kwargs)
elif isinstance(left, TimedeltaArray):
assert_timedelta_array_equal(left, right, **kwargs)
elif isinstance(left, ExtensionArray):
assert_extension_array_equal(left, right, **kwargs)
elif isinstance(left, np.ndarray):
assert_numpy_array_equal(left, right, **kwargs)
elif isinstance(left, str):
assert kwargs == {}
assert left == right
else:
raise NotImplementedError(type(left))
def box_expected(expected, box_cls, transpose=True):
"""
Helper function to wrap the expected output of a test in a given box_class.
Parameters
----------
expected : np.ndarray, Index, Series
box_cls : {Index, Series, DataFrame}
Returns
-------
subclass of box_cls
"""
if box_cls is pd.Index:
expected = pd.Index(expected)
elif box_cls is pd.Series:
expected = pd.Series(expected)
elif box_cls is pd.DataFrame:
expected = pd.Series(expected).to_frame()
if transpose:
# for vector operations, we we need a DataFrame to be a single-row,
# not a single-column, in order to operate against non-DataFrame
# vectors of the same length.
expected = expected.T
elif box_cls is PeriodArray:
# the PeriodArray constructor is not as flexible as period_array
expected = period_array(expected)
elif box_cls is DatetimeArray:
expected = DatetimeArray(expected)
elif box_cls is TimedeltaArray:
expected = TimedeltaArray(expected)
elif box_cls is np.ndarray:
expected = np.array(expected)
elif box_cls is to_array:
expected = to_array(expected)
else:
raise NotImplementedError(box_cls)
return expected
def to_array(obj):
# temporary implementation until we get pd.array in place
if is_period_dtype(obj):
return period_array(obj)
elif is_datetime64_dtype(obj) or is_datetime64tz_dtype(obj):
return DatetimeArray._from_sequence(obj)
elif is_timedelta64_dtype(obj):
return TimedeltaArray._from_sequence(obj)
else:
return np.array(obj)
# -----------------------------------------------------------------------------
# Sparse
def assert_sp_array_equal(
left,
right,
check_dtype=True,
check_kind=True,
check_fill_value=True,
consolidate_block_indices=False,
):
"""
Check that the left and right SparseArray are equal.
Parameters
----------
left : SparseArray
right : SparseArray
check_dtype : bool, default True
Whether to check the data dtype is identical.
check_kind : bool, default True
Whether to just the kind of the sparse index for each column.
check_fill_value : bool, default True
Whether to check that left.fill_value matches right.fill_value
consolidate_block_indices : bool, default False
Whether to consolidate contiguous blocks for sparse arrays with
a BlockIndex. Some operations, e.g. concat, will end up with
block indices that could be consolidated. Setting this to true will
create a new BlockIndex for that array, with consolidated
block indices.
"""
_check_isinstance(left, right, pd.arrays.SparseArray)
assert_numpy_array_equal(left.sp_values, right.sp_values, check_dtype=check_dtype)
# SparseIndex comparison
assert isinstance(left.sp_index, pd._libs.sparse.SparseIndex)
assert isinstance(right.sp_index, pd._libs.sparse.SparseIndex)
if not check_kind:
left_index = left.sp_index.to_block_index()
right_index = right.sp_index.to_block_index()
else:
left_index = left.sp_index
right_index = right.sp_index
if consolidate_block_indices and left.kind == "block":
# we'll probably remove this hack...
left_index = left_index.to_int_index().to_block_index()
right_index = right_index.to_int_index().to_block_index()
if not left_index.equals(right_index):
raise_assert_detail(
"SparseArray.index", "index are not equal", left_index, right_index
)
else:
# Just ensure a
pass
if check_fill_value:
assert_attr_equal("fill_value", left, right)
if check_dtype:
assert_attr_equal("dtype", left, right)
assert_numpy_array_equal(left.to_dense(), right.to_dense(), check_dtype=check_dtype)
# -----------------------------------------------------------------------------
# Others
def assert_contains_all(iterable, dic):
for k in iterable:
assert k in dic, f"Did not contain item: {repr(k)}"
def assert_copy(iter1, iter2, **eql_kwargs):
"""
iter1, iter2: iterables that produce elements
comparable with assert_almost_equal
Checks that the elements are equal, but not
the same object. (Does not check that items
in sequences are also not the same object)
"""
for elem1, elem2 in zip(iter1, iter2):
assert_almost_equal(elem1, elem2, **eql_kwargs)
msg = (
f"Expected object {repr(type(elem1))} and object {repr(type(elem2))} to be "
"different objects, but they were the same object."
)
assert elem1 is not elem2, msg
def getCols(k):
return string.ascii_uppercase[:k]
# make index
def makeStringIndex(k=10, name=None):
return Index(rands_array(nchars=10, size=k), name=name)
def makeUnicodeIndex(k=10, name=None):
return Index(randu_array(nchars=10, size=k), name=name)
def makeCategoricalIndex(k=10, n=3, name=None, **kwargs):
""" make a length k index or n categories """
x = rands_array(nchars=4, size=n)
return CategoricalIndex(
Categorical.from_codes(np.arange(k) % n, categories=x), name=name, **kwargs
)
def makeIntervalIndex(k=10, name=None, **kwargs):
""" make a length k IntervalIndex """
x = np.linspace(0, 100, num=(k + 1))
return IntervalIndex.from_breaks(x, name=name, **kwargs)
def makeBoolIndex(k=10, name=None):
if k == 1:
return Index([True], name=name)
elif k == 2:
return Index([False, True], name=name)
return Index([False, True] + [False] * (k - 2), name=name)
def makeIntIndex(k=10, name=None):
return Index(list(range(k)), name=name)
def makeUIntIndex(k=10, name=None):
return Index([2 ** 63 + i for i in range(k)], name=name)
def makeRangeIndex(k=10, name=None, **kwargs):
return RangeIndex(0, k, 1, name=name, **kwargs)
def makeFloatIndex(k=10, name=None):
values = sorted(np.random.random_sample(k)) - np.random.random_sample(1)
return Index(values * (10 ** np.random.randint(0, 9)), name=name)
def makeDateIndex(k=10, freq="B", name=None, **kwargs):
dt = datetime(2000, 1, 1)
dr = bdate_range(dt, periods=k, freq=freq, name=name)
return DatetimeIndex(dr, name=name, **kwargs)
def makeTimedeltaIndex(k=10, freq="D", name=None, **kwargs):
return pd.timedelta_range(start="1 day", periods=k, freq=freq, name=name, **kwargs)
def makePeriodIndex(k=10, name=None, **kwargs):
dt = datetime(2000, 1, 1)
dr = pd.period_range(start=dt, periods=k, freq="B", name=name, **kwargs)
return dr
def makeMultiIndex(k=10, names=None, **kwargs):
return MultiIndex.from_product((("foo", "bar"), (1, 2)), names=names, **kwargs)
_names = [
"Alice",
"Bob",
"Charlie",
"Dan",
"Edith",
"Frank",
"George",
"Hannah",
"Ingrid",
"Jerry",
"Kevin",
"Laura",
"Michael",
"Norbert",
"Oliver",
"Patricia",
"Quinn",
"Ray",
"Sarah",
"Tim",
"Ursula",
"Victor",
"Wendy",
"Xavier",
"Yvonne",
"Zelda",
]
def _make_timeseries(start="2000-01-01", end="2000-12-31", freq="1D", seed=None):
"""
Make a DataFrame with a DatetimeIndex
Parameters
----------
start : str or Timestamp, default "2000-01-01"
The start of the index. Passed to date_range with `freq`.
end : str or Timestamp, default "2000-12-31"
The end of the index. Passed to date_range with `freq`.
freq : str or Freq
The frequency to use for the DatetimeIndex
seed : int, optional
The random state seed.
* name : object dtype with string names
* id : int dtype with
* x, y : float dtype
Examples
--------
>>> _make_timeseries()
id name x y
timestamp
2000-01-01 982 Frank 0.031261 0.986727
2000-01-02 1025 Edith -0.086358 -0.032920
2000-01-03 982 Edith 0.473177 0.298654
2000-01-04 1009 Sarah 0.534344 -0.750377
2000-01-05 963 Zelda -0.271573 0.054424
... ... ... ... ...
2000-12-27 980 Ingrid -0.132333 -0.422195
2000-12-28 972 Frank -0.376007 -0.298687
2000-12-29 1009 Ursula -0.865047 -0.503133
2000-12-30 1000 Hannah -0.063757 -0.507336
2000-12-31 972 Tim -0.869120 0.531685
"""
index = pd.date_range(start=start, end=end, freq=freq, name="timestamp")
n = len(index)
state = np.random.RandomState(seed)
columns = {
"name": state.choice(_names, size=n),
"id": state.poisson(1000, size=n),
"x": state.rand(n) * 2 - 1,
"y": state.rand(n) * 2 - 1,
}
df = pd.DataFrame(columns, index=index, columns=sorted(columns))
if df.index[-1] == end:
df = df.iloc[:-1]
return df
def all_index_generator(k=10):
"""
Generator which can be iterated over to get instances of all the various
index classes.
Parameters
----------
k: length of each of the index instances
"""
all_make_index_funcs = [
makeIntIndex,
makeFloatIndex,
makeStringIndex,
makeUnicodeIndex,
makeDateIndex,
makePeriodIndex,
makeTimedeltaIndex,
makeBoolIndex,
makeRangeIndex,
makeIntervalIndex,
makeCategoricalIndex,
]
for make_index_func in all_make_index_funcs:
yield make_index_func(k=k)
def index_subclass_makers_generator():
make_index_funcs = [
makeDateIndex,
makePeriodIndex,
makeTimedeltaIndex,
makeRangeIndex,
makeIntervalIndex,
makeCategoricalIndex,
makeMultiIndex,
]
for make_index_func in make_index_funcs:
yield make_index_func
def all_timeseries_index_generator(k=10):
"""
Generator which can be iterated over to get instances of all the classes
which represent time-series.
Parameters
----------
k: length of each of the index instances
"""
make_index_funcs = [makeDateIndex, makePeriodIndex, makeTimedeltaIndex]
for make_index_func in make_index_funcs:
yield make_index_func(k=k)
# make series
def makeFloatSeries(name=None):
index = makeStringIndex(N)
return Series(randn(N), index=index, name=name)
def makeStringSeries(name=None):
index = makeStringIndex(N)
return Series(randn(N), index=index, name=name)
def makeObjectSeries(name=None):
data = makeStringIndex(N)
data = Index(data, dtype=object)
index = makeStringIndex(N)
return Series(data, index=index, name=name)
def getSeriesData():
index = makeStringIndex(N)
return {c: Series(randn(N), index=index) for c in getCols(K)}
def makeTimeSeries(nper=None, freq="B", name=None):
if nper is None:
nper = N
return Series(randn(nper), index=makeDateIndex(nper, freq=freq), name=name)
def makePeriodSeries(nper=None, name=None):
if nper is None:
nper = N
return Series(randn(nper), index=makePeriodIndex(nper), name=name)
def getTimeSeriesData(nper=None, freq="B"):
return {c: makeTimeSeries(nper, freq) for c in getCols(K)}
def getPeriodData(nper=None):
return {c: makePeriodSeries(nper) for c in getCols(K)}
# make frame
def makeTimeDataFrame(nper=None, freq="B"):
data = getTimeSeriesData(nper, freq)
return DataFrame(data)
def makeDataFrame():
data = getSeriesData()
return DataFrame(data)
def getMixedTypeDict():
index = Index(["a", "b", "c", "d", "e"])
data = {
"A": [0.0, 1.0, 2.0, 3.0, 4.0],
"B": [0.0, 1.0, 0.0, 1.0, 0.0],
"C": ["foo1", "foo2", "foo3", "foo4", "foo5"],
"D": bdate_range("1/1/2009", periods=5),
}
return index, data
def makeMixedDataFrame():
return DataFrame(getMixedTypeDict()[1])
def makePeriodFrame(nper=None):
data = getPeriodData(nper)
return DataFrame(data)
def makeCustomIndex(
nentries, nlevels, prefix="#", names=False, ndupe_l=None, idx_type=None
):
"""
Create an index/multindex with given dimensions, levels, names, etc'
nentries - number of entries in index
nlevels - number of levels (> 1 produces multindex)
prefix - a string prefix for labels
names - (Optional), bool or list of strings. if True will use default
names, if false will use no names, if a list is given, the name of
each level in the index will be taken from the list.
ndupe_l - (Optional), list of ints, the number of rows for which the
label will repeated at the corresponding level, you can specify just
the first few, the rest will use the default ndupe_l of 1.
len(ndupe_l) <= nlevels.
idx_type - "i"/"f"/"s"/"u"/"dt"/"p"/"td".
If idx_type is not None, `idx_nlevels` must be 1.
"i"/"f" creates an integer/float index,
"s"/"u" creates a string/unicode index
"dt" create a datetime index.
"td" create a datetime index.
if unspecified, string labels will be generated.
"""
if ndupe_l is None:
ndupe_l = [1] * nlevels
assert is_sequence(ndupe_l) and len(ndupe_l) <= nlevels
assert names is None or names is False or names is True or len(names) is nlevels
assert idx_type is None or (
idx_type in ("i", "f", "s", "u", "dt", "p", "td") and nlevels == 1
)
if names is True:
# build default names
names = [prefix + str(i) for i in range(nlevels)]
if names is False:
# pass None to index constructor for no name
names = None
# make singleton case uniform
if isinstance(names, str) and nlevels == 1:
names = [names]
# specific 1D index type requested?
idx_func = dict(
i=makeIntIndex,
f=makeFloatIndex,
s=makeStringIndex,
u=makeUnicodeIndex,
dt=makeDateIndex,
td=makeTimedeltaIndex,
p=makePeriodIndex,
).get(idx_type)
if idx_func:
idx = idx_func(nentries)
# but we need to fill in the name
if names:
idx.name = names[0]
return idx
elif idx_type is not None:
raise ValueError(
f"{repr(idx_type)} is not a legal value for `idx_type`, "
"use 'i'/'f'/'s'/'u'/'dt'/'p'/'td'."
)
if len(ndupe_l) < nlevels:
ndupe_l.extend([1] * (nlevels - len(ndupe_l)))
assert len(ndupe_l) == nlevels
assert all(x > 0 for x in ndupe_l)
tuples = []
for i in range(nlevels):
def keyfunc(x):
import re
numeric_tuple = re.sub(r"[^\d_]_?", "", x).split("_")
return [int(num) for num in numeric_tuple]
# build a list of lists to create the index from
div_factor = nentries // ndupe_l[i] + 1
cnt = Counter()
for j in range(div_factor):
label = f"{prefix}_l{i}_g{j}"
cnt[label] = ndupe_l[i]
# cute Counter trick
result = sorted(cnt.elements(), key=keyfunc)[:nentries]
tuples.append(result)
tuples = list(zip(*tuples))
# convert tuples to index
if nentries == 1:
# we have a single level of tuples, i.e. a regular Index
index = Index(tuples[0], name=names[0])
elif nlevels == 1:
name = None if names is None else names[0]
index = Index((x[0] for x in tuples), name=name)
else:
index = MultiIndex.from_tuples(tuples, names=names)
return index
def makeCustomDataframe(
nrows,
ncols,
c_idx_names=True,
r_idx_names=True,
c_idx_nlevels=1,
r_idx_nlevels=1,
data_gen_f=None,
c_ndupe_l=None,
r_ndupe_l=None,
dtype=None,
c_idx_type=None,
r_idx_type=None,
):
"""
Create a DataFrame using supplied parameters.
Parameters
----------
nrows, ncols - number of data rows/cols
c_idx_names, idx_names - False/True/list of strings, yields No names ,
default names or uses the provided names for the levels of the
corresponding index. You can provide a single string when
c_idx_nlevels ==1.
c_idx_nlevels - number of levels in columns index. > 1 will yield MultiIndex
r_idx_nlevels - number of levels in rows index. > 1 will yield MultiIndex
data_gen_f - a function f(row,col) which return the data value
at that position, the default generator used yields values of the form
"RxCy" based on position.
c_ndupe_l, r_ndupe_l - list of integers, determines the number
of duplicates for each label at a given level of the corresponding
index. The default `None` value produces a multiplicity of 1 across
all levels, i.e. a unique index. Will accept a partial list of length
N < idx_nlevels, for just the first N levels. If ndupe doesn't divide
nrows/ncol, the last label might have lower multiplicity.
dtype - passed to the DataFrame constructor as is, in case you wish to
have more control in conjunction with a custom `data_gen_f`
r_idx_type, c_idx_type - "i"/"f"/"s"/"u"/"dt"/"td".
If idx_type is not None, `idx_nlevels` must be 1.
"i"/"f" creates an integer/float index,
"s"/"u" creates a string/unicode index
"dt" create a datetime index.
"td" create a timedelta index.
if unspecified, string labels will be generated.
Examples
--------
# 5 row, 3 columns, default names on both, single index on both axis
>> makeCustomDataframe(5,3)
# make the data a random int between 1 and 100
>> mkdf(5,3,data_gen_f=lambda r,c:randint(1,100))
# 2-level multiindex on rows with each label duplicated
# twice on first level, default names on both axis, single
# index on both axis
>> a=makeCustomDataframe(5,3,r_idx_nlevels=2,r_ndupe_l=[2])
# DatetimeIndex on row, index with unicode labels on columns
# no names on either axis
>> a=makeCustomDataframe(5,3,c_idx_names=False,r_idx_names=False,
r_idx_type="dt",c_idx_type="u")
# 4-level multindex on rows with names provided, 2-level multindex
# on columns with default labels and default names.
>> a=makeCustomDataframe(5,3,r_idx_nlevels=4,
r_idx_names=["FEE","FI","FO","FAM"],
c_idx_nlevels=2)
>> a=mkdf(5,3,r_idx_nlevels=2,c_idx_nlevels=4)
"""
assert c_idx_nlevels > 0
assert r_idx_nlevels > 0
assert r_idx_type is None or (
r_idx_type in ("i", "f", "s", "u", "dt", "p", "td") and r_idx_nlevels == 1
)
assert c_idx_type is None or (
c_idx_type in ("i", "f", "s", "u", "dt", "p", "td") and c_idx_nlevels == 1
)
columns = makeCustomIndex(
ncols,
nlevels=c_idx_nlevels,
prefix="C",
names=c_idx_names,
ndupe_l=c_ndupe_l,
idx_type=c_idx_type,
)
index = makeCustomIndex(
nrows,
nlevels=r_idx_nlevels,
prefix="R",
names=r_idx_names,
ndupe_l=r_ndupe_l,
idx_type=r_idx_type,
)
# by default, generate data based on location
if data_gen_f is None:
data_gen_f = lambda r, c: f"R{r}C{c}"
data = [[data_gen_f(r, c) for c in range(ncols)] for r in range(nrows)]
return DataFrame(data, index, columns, dtype=dtype)
def _create_missing_idx(nrows, ncols, density, random_state=None):
if random_state is None:
random_state = np.random
else:
random_state = np.random.RandomState(random_state)
# below is cribbed from scipy.sparse
size = int(np.round((1 - density) * nrows * ncols))
# generate a few more to ensure unique values
min_rows = 5
fac = 1.02
extra_size = min(size + min_rows, fac * size)
def _gen_unique_rand(rng, _extra_size):
ind = rng.rand(int(_extra_size))
return np.unique(np.floor(ind * nrows * ncols))[:size]
ind = _gen_unique_rand(random_state, extra_size)
while ind.size < size:
extra_size *= 1.05
ind = _gen_unique_rand(random_state, extra_size)
j = np.floor(ind * 1.0 / nrows).astype(int)
i = (ind - j * nrows).astype(int)
return i.tolist(), j.tolist()
def makeMissingCustomDataframe(
nrows,
ncols,
density=0.9,
random_state=None,
c_idx_names=True,
r_idx_names=True,
c_idx_nlevels=1,
r_idx_nlevels=1,
data_gen_f=None,
c_ndupe_l=None,
r_ndupe_l=None,
dtype=None,
c_idx_type=None,
r_idx_type=None,
):
"""
Parameters
----------
Density : float, optional
Float in (0, 1) that gives the percentage of non-missing numbers in
the DataFrame.
random_state : {np.random.RandomState, int}, optional
Random number generator or random seed.
See makeCustomDataframe for descriptions of the rest of the parameters.
"""
df = makeCustomDataframe(
nrows,
ncols,
c_idx_names=c_idx_names,
r_idx_names=r_idx_names,
c_idx_nlevels=c_idx_nlevels,
r_idx_nlevels=r_idx_nlevels,
data_gen_f=data_gen_f,
c_ndupe_l=c_ndupe_l,
r_ndupe_l=r_ndupe_l,
dtype=dtype,
c_idx_type=c_idx_type,
r_idx_type=r_idx_type,
)
i, j = _create_missing_idx(nrows, ncols, density, random_state)
df.values[i, j] = np.nan
return df
def makeMissingDataframe(density=0.9, random_state=None):
df = makeDataFrame()
i, j = _create_missing_idx(*df.shape, density=density, random_state=random_state)
df.values[i, j] = np.nan
return df
def optional_args(decorator):
"""
allows a decorator to take optional positional and keyword arguments.
Assumes that taking a single, callable, positional argument means that
it is decorating a function, i.e. something like this::
@my_decorator
def function(): pass
Calls decorator with decorator(f, *args, **kwargs)
"""
@wraps(decorator)
def wrapper(*args, **kwargs):
def dec(f):
return decorator(f, *args, **kwargs)
is_decorating = not kwargs and len(args) == 1 and callable(args[0])
if is_decorating:
f = args[0]
args = []
return dec(f)
else:
return dec
return wrapper
# skip tests on exceptions with this message
_network_error_messages = (
# 'urlopen error timed out',
# 'timeout: timed out',
# 'socket.timeout: timed out',
"timed out",
"Server Hangup",
"HTTP Error 503: Service Unavailable",
"502: Proxy Error",
"HTTP Error 502: internal error",
"HTTP Error 502",
"HTTP Error 503",
"HTTP Error 403",
"HTTP Error 400",
"Temporary failure in name resolution",
"Name or service not known",
"Connection refused",
"certificate verify",
)
# or this e.errno/e.reason.errno
_network_errno_vals = (
101, # Network is unreachable
111, # Connection refused
110, # Connection timed out
104, # Connection reset Error
54, # Connection reset by peer
60, # urllib.error.URLError: [Errno 60] Connection timed out
)
# Both of the above shouldn't mask real issues such as 404's
# or refused connections (changed DNS).
# But some tests (test_data yahoo) contact incredibly flakey
# servers.
# and conditionally raise on exception types in _get_default_network_errors
def _get_default_network_errors():
# Lazy import for http.client because it imports many things from the stdlib
import http.client
return (IOError, http.client.HTTPException, TimeoutError)
def can_connect(url, error_classes=None):
"""
Try to connect to the given url. True if succeeds, False if IOError
raised
Parameters
----------
url : basestring
The URL to try to connect to
Returns
-------
connectable : bool
Return True if no IOError (unable to connect) or URLError (bad url) was
raised
"""
if error_classes is None:
error_classes = _get_default_network_errors()
try:
with urlopen(url):
pass
except error_classes:
return False
else:
return True
@optional_args
def network(
t,
url="http://www.google.com",
raise_on_error=_RAISE_NETWORK_ERROR_DEFAULT,
check_before_test=False,
error_classes=None,
skip_errnos=_network_errno_vals,
_skip_on_messages=_network_error_messages,
):
"""
Label a test as requiring network connection and, if an error is
encountered, only raise if it does not find a network connection.
In comparison to ``network``, this assumes an added contract to your test:
you must assert that, under normal conditions, your test will ONLY fail if
it does not have network connectivity.
You can call this in 3 ways: as a standard decorator, with keyword
arguments, or with a positional argument that is the url to check.
Parameters
----------
t : callable
The test requiring network connectivity.
url : path
The url to test via ``pandas.io.common.urlopen`` to check
for connectivity. Defaults to 'http://www.google.com'.
raise_on_error : bool
If True, never catches errors.
check_before_test : bool
If True, checks connectivity before running the test case.
error_classes : tuple or Exception
error classes to ignore. If not in ``error_classes``, raises the error.
defaults to IOError. Be careful about changing the error classes here.
skip_errnos : iterable of int
Any exception that has .errno or .reason.erno set to one
of these values will be skipped with an appropriate
message.
_skip_on_messages: iterable of string
any exception e for which one of the strings is
a substring of str(e) will be skipped with an appropriate
message. Intended to suppress errors where an errno isn't available.
Notes
-----
* ``raise_on_error`` supercedes ``check_before_test``
Returns
-------
t : callable
The decorated test ``t``, with checks for connectivity errors.
Example
-------
Tests decorated with @network will fail if it's possible to make a network
connection to another URL (defaults to google.com)::
>>> from pandas._testing import network
>>> from pandas.io.common import urlopen
>>> @network
... def test_network():
... with urlopen("rabbit://bonanza.com"):
... pass
Traceback
...
URLError: <urlopen error unknown url type: rabit>
You can specify alternative URLs::
>>> @network("http://www.yahoo.com")
... def test_something_with_yahoo():
... raise IOError("Failure Message")
>>> test_something_with_yahoo()
Traceback (most recent call last):
...
IOError: Failure Message
If you set check_before_test, it will check the url first and not run the
test on failure::
>>> @network("failing://url.blaher", check_before_test=True)
... def test_something():
... print("I ran!")
... raise ValueError("Failure")
>>> test_something()
Traceback (most recent call last):
...
Errors not related to networking will always be raised.
"""
from pytest import skip
if error_classes is None:
error_classes = _get_default_network_errors()
t.network = True
@wraps(t)
def wrapper(*args, **kwargs):
if check_before_test and not raise_on_error:
if not can_connect(url, error_classes):
skip()
try:
return t(*args, **kwargs)
except Exception as err:
errno = getattr(err, "errno", None)
if not errno and hasattr(errno, "reason"):
errno = getattr(err.reason, "errno", None)
if errno in skip_errnos:
skip(f"Skipping test due to known errno and error {err}")
e_str = str(err)
if any(m.lower() in e_str.lower() for m in _skip_on_messages):
skip(
f"Skipping test because exception message is known and error {err}"
)
if not isinstance(err, error_classes):
raise
if raise_on_error or can_connect(url, error_classes):
raise
else:
skip(f"Skipping test due to lack of connectivity and error {err}")
return wrapper
with_connectivity_check = network
@contextmanager
def assert_produces_warning(
expected_warning=Warning,
filter_level="always",
clear=None,
check_stacklevel=True,
raise_on_extra_warnings=True,
):
"""
Context manager for running code expected to either raise a specific
warning, or not raise any warnings. Verifies that the code raises the
expected warning, and that it does not raise any other unexpected
warnings. It is basically a wrapper around ``warnings.catch_warnings``.
Parameters
----------
expected_warning : {Warning, False, None}, default Warning
The type of Exception raised. ``exception.Warning`` is the base
class for all warnings. To check that no warning is returned,
specify ``False`` or ``None``.
filter_level : str or None, default "always"
Specifies whether warnings are ignored, displayed, or turned
into errors.
Valid values are:
* "error" - turns matching warnings into exceptions
* "ignore" - discard the warning
* "always" - always emit a warning
* "default" - print the warning the first time it is generated
from each location
* "module" - print the warning the first time it is generated
from each module
* "once" - print the warning the first time it is generated
clear : str, default None
If not ``None`` then remove any previously raised warnings from
the ``__warningsregistry__`` to ensure that no warning messages are
suppressed by this context manager. If ``None`` is specified,
the ``__warningsregistry__`` keeps track of which warnings have been
shown, and does not show them again.
check_stacklevel : bool, default True
If True, displays the line that called the function containing
the warning to show were the function is called. Otherwise, the
line that implements the function is displayed.
raise_on_extra_warnings : bool, default True
Whether extra warnings not of the type `expected_warning` should
cause the test to fail.
Examples
--------
>>> import warnings
>>> with assert_produces_warning():
... warnings.warn(UserWarning())
...
>>> with assert_produces_warning(False):
... warnings.warn(RuntimeWarning())
...
Traceback (most recent call last):
...
AssertionError: Caused unexpected warning(s): ['RuntimeWarning'].
>>> with assert_produces_warning(UserWarning):
... warnings.warn(RuntimeWarning())
Traceback (most recent call last):
...
AssertionError: Did not see expected warning of class 'UserWarning'.
..warn:: This is *not* thread-safe.
"""
__tracebackhide__ = True
with warnings.catch_warnings(record=True) as w:
if clear is not None:
# make sure that we are clearing these warnings
# if they have happened before
# to guarantee that we will catch them
if not is_list_like(clear):
clear = [clear]
for m in clear:
try:
m.__warningregistry__.clear()
except AttributeError:
# module may not have __warningregistry__
pass
saw_warning = False
warnings.simplefilter(filter_level)
yield w
extra_warnings = []
for actual_warning in w:
if expected_warning and issubclass(
actual_warning.category, expected_warning
):
saw_warning = True
if check_stacklevel and issubclass(
actual_warning.category, (FutureWarning, DeprecationWarning)
):
from inspect import getframeinfo, stack
caller = getframeinfo(stack()[2][0])
msg = (
"Warning not set with correct stacklevel. "
f"File where warning is raised: {actual_warning.filename} != "
f"{caller.filename}. Warning message: {actual_warning.message}"
)
assert actual_warning.filename == caller.filename, msg
else:
extra_warnings.append(
(
actual_warning.category.__name__,
actual_warning.message,
actual_warning.filename,
actual_warning.lineno,
)
)
if expected_warning:
msg = (
f"Did not see expected warning of class "
f"{repr(expected_warning.__name__)}"
)
assert saw_warning, msg
if raise_on_extra_warnings and extra_warnings:
raise AssertionError(
f"Caused unexpected warning(s): {repr(extra_warnings)}"
)
class RNGContext:
"""
Context manager to set the numpy random number generator speed. Returns
to the original value upon exiting the context manager.
Parameters
----------
seed : int
Seed for numpy.random.seed
Examples
--------
with RNGContext(42):
np.random.randn()
"""
def __init__(self, seed):
self.seed = seed
def __enter__(self):
self.start_state = np.random.get_state()
np.random.seed(self.seed)
def __exit__(self, exc_type, exc_value, traceback):
np.random.set_state(self.start_state)
@contextmanager
def with_csv_dialect(name, **kwargs):
"""
Context manager to temporarily register a CSV dialect for parsing CSV.
Parameters
----------
name : str
The name of the dialect.
kwargs : mapping
The parameters for the dialect.
Raises
------
ValueError : the name of the dialect conflicts with a builtin one.
See Also
--------
csv : Python's CSV library.
"""
import csv
_BUILTIN_DIALECTS = {"excel", "excel-tab", "unix"}
if name in _BUILTIN_DIALECTS:
raise ValueError("Cannot override builtin dialect.")
csv.register_dialect(name, **kwargs)
yield
csv.unregister_dialect(name)
@contextmanager
def use_numexpr(use, min_elements=None):
from pandas.core.computation import expressions as expr
if min_elements is None:
min_elements = expr._MIN_ELEMENTS
olduse = expr._USE_NUMEXPR
oldmin = expr._MIN_ELEMENTS
expr.set_use_numexpr(use)
expr._MIN_ELEMENTS = min_elements
yield
expr._MIN_ELEMENTS = oldmin
expr.set_use_numexpr(olduse)
def test_parallel(num_threads=2, kwargs_list=None):
"""
Decorator to run the same function multiple times in parallel.
Parameters
----------
num_threads : int, optional
The number of times the function is run in parallel.
kwargs_list : list of dicts, optional
The list of kwargs to update original
function kwargs on different threads.
Notes
-----
This decorator does not pass the return value of the decorated function.
Original from scikit-image:
https://github.com/scikit-image/scikit-image/pull/1519
"""
assert num_threads > 0
has_kwargs_list = kwargs_list is not None
if has_kwargs_list:
assert len(kwargs_list) == num_threads
import threading
def wrapper(func):
@wraps(func)
def inner(*args, **kwargs):
if has_kwargs_list:
update_kwargs = lambda i: dict(kwargs, **kwargs_list[i])
else:
update_kwargs = lambda i: kwargs
threads = []
for i in range(num_threads):
updated_kwargs = update_kwargs(i)
thread = threading.Thread(target=func, args=args, kwargs=updated_kwargs)
threads.append(thread)
for thread in threads:
thread.start()
for thread in threads:
thread.join()
return inner
return wrapper
class SubclassedSeries(Series):
_metadata = ["testattr", "name"]
@property
def _constructor(self):
return SubclassedSeries
@property
def _constructor_expanddim(self):
return SubclassedDataFrame
class SubclassedDataFrame(DataFrame):
_metadata = ["testattr"]
@property
def _constructor(self):
return SubclassedDataFrame
@property
def _constructor_sliced(self):
return SubclassedSeries
class SubclassedCategorical(Categorical):
@property
def _constructor(self):
return SubclassedCategorical
@contextmanager
def set_timezone(tz: str):
"""
Context manager for temporarily setting a timezone.
Parameters
----------
tz : str
A string representing a valid timezone.
Examples
--------
>>> from datetime import datetime
>>> from dateutil.tz import tzlocal
>>> tzlocal().tzname(datetime.now())
'IST'
>>> with set_timezone('US/Eastern'):
... tzlocal().tzname(datetime.now())
...
'EDT'
"""
import os
import time
def setTZ(tz):
if tz is None:
try:
del os.environ["TZ"]
except KeyError:
pass
else:
os.environ["TZ"] = tz
time.tzset()
orig_tz = os.environ.get("TZ")
setTZ(tz)
try:
yield
finally:
setTZ(orig_tz)
def _make_skipna_wrapper(alternative, skipna_alternative=None):
"""
Create a function for calling on an array.
Parameters
----------
alternative : function
The function to be called on the array with no NaNs.
Only used when 'skipna_alternative' is None.
skipna_alternative : function
The function to be called on the original array
Returns
-------
function
"""
if skipna_alternative:
def skipna_wrapper(x):
return skipna_alternative(x.values)
else:
def skipna_wrapper(x):
nona = x.dropna()
if len(nona) == 0:
return np.nan
return alternative(nona)
return skipna_wrapper
def convert_rows_list_to_csv_str(rows_list: List[str]):
"""
Convert list of CSV rows to single CSV-formatted string for current OS.
This method is used for creating expected value of to_csv() method.
Parameters
----------
rows_list : List[str]
Each element represents the row of csv.
Returns
-------
str
Expected output of to_csv() in current OS.
"""
sep = os.linesep
expected = sep.join(rows_list) + sep
return expected
def external_error_raised(
expected_exception: Type[Exception],
) -> Callable[[Type[Exception], None], None]:
"""
Helper function to mark pytest.raises that have an external error message.
Parameters
----------
expected_exception : Exception
Expected error to raise.
Returns
-------
Callable
Regular `pytest.raises` function with `match` equal to `None`.
"""
import pytest
return pytest.raises(expected_exception, match=None)
import bz2
from collections import Counter
from contextlib import contextmanager
from datetime import datetime
from functools import wraps
import gzip
import os
from shutil import rmtree
import string
import tempfile
from typing import Any, Callable, List, Optional, Type, Union, cast
import warnings
import zipfile
import numpy as np
from numpy.random import rand, randn
from pandas._config.localization import ( # noqa:F401
can_set_locale,
get_locales,
set_locale,
)
import pandas._libs.testing as _testing
from pandas._typing import FilePathOrBuffer, FrameOrSeries
from pandas.compat import _get_lzma_file, _import_lzma
from pandas.core.dtypes.common import (
is_bool,
is_categorical_dtype,
is_datetime64_dtype,
is_datetime64tz_dtype,
is_extension_array_dtype,
is_interval_dtype,
is_list_like,
is_number,
is_period_dtype,
is_sequence,
is_timedelta64_dtype,
needs_i8_conversion,
)
from pandas.core.dtypes.missing import array_equivalent
import pandas as pd
from pandas import (
Categorical,
CategoricalIndex,
DataFrame,
DatetimeIndex,
Index,
IntervalIndex,
MultiIndex,
RangeIndex,
Series,
bdate_range,
)
from pandas.core.algorithms import take_1d
from pandas.core.arrays import (
DatetimeArray,
ExtensionArray,
IntervalArray,
PeriodArray,
TimedeltaArray,
period_array,
)
from pandas.io.common import urlopen
from pandas.io.formats.printing import pprint_thing
lzma = _import_lzma()
N = 30
K = 4
_RAISE_NETWORK_ERROR_DEFAULT = False
# set testing_mode
_testing_mode_warnings = (DeprecationWarning, ResourceWarning)
def set_testing_mode():
# set the testing mode filters
testing_mode = os.environ.get("PANDAS_TESTING_MODE", "None")
if "deprecate" in testing_mode:
warnings.simplefilter("always", _testing_mode_warnings)
def reset_testing_mode():
# reset the testing mode filters
testing_mode = os.environ.get("PANDAS_TESTING_MODE", "None")
if "deprecate" in testing_mode:
warnings.simplefilter("ignore", _testing_mode_warnings)
set_testing_mode()
def reset_display_options():
"""
Reset the display options for printing and representing objects.
"""
pd.reset_option("^display.", silent=True)
def round_trip_pickle(
obj: Any, path: Optional[FilePathOrBuffer] = None
) -> FrameOrSeries:
"""
Pickle an object and then read it again.
Parameters
----------
obj : any object
The object to pickle and then re-read.
path : str, path object or file-like object, default None
The path where the pickled object is written and then read.
Returns
-------
pandas object
The original object that was pickled and then re-read.
"""
_path = path
if _path is None:
_path = f"__{rands(10)}__.pickle"
with ensure_clean(_path) as temp_path:
pd.to_pickle(obj, temp_path)
return pd.read_pickle(temp_path)
def round_trip_pathlib(writer, reader, path: Optional[str] = None):
"""
Write an object to file specified by a pathlib.Path and read it back
Parameters
----------
writer : callable bound to pandas object
IO writing function (e.g. DataFrame.to_csv )
reader : callable
IO reading function (e.g. pd.read_csv )
path : str, default None
The path where the object is written and then read.
Returns
-------
pandas object
The original object that was serialized and then re-read.
"""
import pytest
Path = pytest.importorskip("pathlib").Path
if path is None:
path = "___pathlib___"
with ensure_clean(path) as path:
writer(Path(path))
obj = reader(Path(path))
return obj
def round_trip_localpath(writer, reader, path: Optional[str] = None):
"""
Write an object to file specified by a py.path LocalPath and read it back.
Parameters
----------
writer : callable bound to pandas object
IO writing function (e.g. DataFrame.to_csv )
reader : callable
IO reading function (e.g. pd.read_csv )
path : str, default None
The path where the object is written and then read.
Returns
-------
pandas object
The original object that was serialized and then re-read.
"""
import pytest
LocalPath = pytest.importorskip("py.path").local
if path is None:
path = "___localpath___"
with ensure_clean(path) as path:
writer(LocalPath(path))
obj = reader(LocalPath(path))
return obj
@contextmanager
def decompress_file(path, compression):
"""
Open a compressed file and return a file object.
Parameters
----------
path : str
The path where the file is read from.
compression : {'gzip', 'bz2', 'zip', 'xz', None}
Name of the decompression to use
Returns
-------
file object
"""
if compression is None:
f = open(path, "rb")
elif compression == "gzip":
f = gzip.open(path, "rb")
elif compression == "bz2":
f = bz2.BZ2File(path, "rb")
elif compression == "xz":
f = _get_lzma_file(lzma)(path, "rb")
elif compression == "zip":
zip_file = zipfile.ZipFile(path)
zip_names = zip_file.namelist()
if len(zip_names) == 1:
f = zip_file.open(zip_names.pop())
else:
raise ValueError(f"ZIP file {path} error. Only one file per ZIP.")
else:
raise ValueError(f"Unrecognized compression type: {compression}")
try:
yield f
finally:
f.close()
if compression == "zip":
zip_file.close()
def write_to_compressed(compression, path, data, dest="test"):
"""
Write data to a compressed file.
Parameters
----------
compression : {'gzip', 'bz2', 'zip', 'xz'}
The compression type to use.
path : str
The file path to write the data.
data : str
The data to write.
dest : str, default "test"
The destination file (for ZIP only)
Raises
------
ValueError : An invalid compression value was passed in.
"""
if compression == "zip":
import zipfile
compress_method = zipfile.ZipFile
elif compression == "gzip":
import gzip
compress_method = gzip.GzipFile
elif compression == "bz2":
import bz2
compress_method = bz2.BZ2File
elif compression == "xz":
compress_method = _get_lzma_file(lzma)
else:
raise ValueError(f"Unrecognized compression type: {compression}")
if compression == "zip":
mode = "w"
args = (dest, data)
method = "writestr"
else:
mode = "wb"
args = (data,)
method = "write"
with compress_method(path, mode=mode) as f:
getattr(f, method)(*args)
def assert_almost_equal(
left,
right,
check_dtype: Union[bool, str] = "equiv",
check_less_precise: Union[bool, int] = False,
**kwargs,
):
"""
Check that the left and right objects are approximately equal.
By approximately equal, we refer to objects that are numbers or that
contain numbers which may be equivalent to specific levels of precision.
Parameters
----------
left : object
right : object
check_dtype : bool or {'equiv'}, default 'equiv'
Check dtype if both a and b are the same type. If 'equiv' is passed in,
then `RangeIndex` and `Int64Index` are also considered equivalent
when doing type checking.
check_less_precise : bool or int, default False
Specify comparison precision. 5 digits (False) or 3 digits (True)
after decimal points are compared. If int, then specify the number
of digits to compare.
When comparing two numbers, if the first number has magnitude less
than 1e-5, we compare the two numbers directly and check whether
they are equivalent within the specified precision. Otherwise, we
compare the **ratio** of the second number to the first number and
check whether it is equivalent to 1 within the specified precision.
"""
if isinstance(left, pd.Index):
assert_index_equal(
left,
right,
check_exact=False,
exact=check_dtype,
check_less_precise=check_less_precise,
**kwargs,
)
elif isinstance(left, pd.Series):
assert_series_equal(
left,
right,
check_exact=False,
check_dtype=check_dtype,
check_less_precise=check_less_precise,
**kwargs,
)
elif isinstance(left, pd.DataFrame):
assert_frame_equal(
left,
right,
check_exact=False,
check_dtype=check_dtype,
check_less_precise=check_less_precise,
**kwargs,
)
else:
# Other sequences.
if check_dtype:
if is_number(left) and is_number(right):
# Do not compare numeric classes, like np.float64 and float.
pass
elif is_bool(left) and is_bool(right):
# Do not compare bool classes, like np.bool_ and bool.
pass
else:
if isinstance(left, np.ndarray) or isinstance(right, np.ndarray):
obj = "numpy array"
else:
obj = "Input"
assert_class_equal(left, right, obj=obj)
_testing.assert_almost_equal(
left,
right,
check_dtype=check_dtype,
check_less_precise=check_less_precise,
**kwargs,
)
def _check_isinstance(left, right, cls):
"""
Helper method for our assert_* methods that ensures that
the two objects being compared have the right type before
proceeding with the comparison.
Parameters
----------
left : The first object being compared.
right : The second object being compared.
cls : The class type to check against.
Raises
------
AssertionError : Either `left` or `right` is not an instance of `cls`.
"""
cls_name = cls.__name__
if not isinstance(left, cls):
raise AssertionError(
f"{cls_name} Expected type {cls}, found {type(left)} instead"
)
if not isinstance(right, cls):
raise AssertionError(
f"{cls_name} Expected type {cls}, found {type(right)} instead"
)
def assert_dict_equal(left, right, compare_keys: bool = True):
_check_isinstance(left, right, dict)
_testing.assert_dict_equal(left, right, compare_keys=compare_keys)
def randbool(size=(), p: float = 0.5):
return rand(*size) <= p
RANDS_CHARS = np.array(list(string.ascii_letters + string.digits), dtype=(np.str_, 1))
RANDU_CHARS = np.array(
list("".join(map(chr, range(1488, 1488 + 26))) + string.digits),
dtype=(np.unicode_, 1),
)
def rands_array(nchars, size, dtype="O"):
"""
Generate an array of byte strings.
"""
retval = (
np.random.choice(RANDS_CHARS, size=nchars * np.prod(size))
.view((np.str_, nchars))
.reshape(size)
)
if dtype is None:
return retval
else:
return retval.astype(dtype)
def randu_array(nchars, size, dtype="O"):
"""
Generate an array of unicode strings.
"""
retval = (
np.random.choice(RANDU_CHARS, size=nchars * np.prod(size))
.view((np.unicode_, nchars))
.reshape(size)
)
if dtype is None:
return retval
else:
return retval.astype(dtype)
def rands(nchars):
"""
Generate one random byte string.
See `rands_array` if you want to create an array of random strings.
"""
return "".join(np.random.choice(RANDS_CHARS, nchars))
def randu(nchars):
"""
Generate one random unicode string.
See `randu_array` if you want to create an array of random unicode strings.
"""
return "".join(np.random.choice(RANDU_CHARS, nchars))
def close(fignum=None):
from matplotlib.pyplot import get_fignums, close as _close
if fignum is None:
for fignum in get_fignums():
_close(fignum)
else:
_close(fignum)
# -----------------------------------------------------------------------------
# contextmanager to ensure the file cleanup
@contextmanager
def ensure_clean(filename=None, return_filelike=False, **kwargs):
"""
Gets a temporary path and agrees to remove on close.
Parameters
----------
filename : str (optional)
if None, creates a temporary file which is then removed when out of
scope. if passed, creates temporary file with filename as ending.
return_filelike : bool (default False)
if True, returns a file-like which is *always* cleaned. Necessary for
savefig and other functions which want to append extensions.
**kwargs
Additional keywords passed in for creating a temporary file.
:meth:`tempFile.TemporaryFile` is used when `return_filelike` is ``True``.
:meth:`tempfile.mkstemp` is used when `return_filelike` is ``False``.
Note that the `filename` parameter will be passed in as the `suffix`
argument to either function.
See Also
--------
tempfile.TemporaryFile
tempfile.mkstemp
"""
filename = filename or ""
fd = None
kwargs["suffix"] = filename
if return_filelike:
f = tempfile.TemporaryFile(**kwargs)
try:
yield f
finally:
f.close()
else:
# Don't generate tempfile if using a path with directory specified.
if len(os.path.dirname(filename)):
raise ValueError("Can't pass a qualified name to ensure_clean()")
try:
fd, filename = tempfile.mkstemp(**kwargs)
except UnicodeEncodeError:
import pytest
pytest.skip("no unicode file names on this system")
try:
yield filename
finally:
try:
os.close(fd)
except OSError:
print(f"Couldn't close file descriptor: {fd} (file: {filename})")
try:
if os.path.exists(filename):
os.remove(filename)
except OSError as e:
print(f"Exception on removing file: {e}")
@contextmanager
def ensure_clean_dir():
"""
Get a temporary directory path and agrees to remove on close.
Yields
------
Temporary directory path
"""
directory_name = tempfile.mkdtemp(suffix="")
try:
yield directory_name
finally:
try:
rmtree(directory_name)
except OSError:
pass
@contextmanager
def ensure_safe_environment_variables():
"""
Get a context manager to safely set environment variables
All changes will be undone on close, hence environment variables set
within this contextmanager will neither persist nor change global state.
"""
saved_environ = dict(os.environ)
try:
yield
finally:
os.environ.clear()
os.environ.update(saved_environ)
# -----------------------------------------------------------------------------
# Comparators
def equalContents(arr1, arr2) -> bool:
"""
Checks if the set of unique elements of arr1 and arr2 are equivalent.
"""
return frozenset(arr1) == frozenset(arr2)
def assert_index_equal(
left: Index,
right: Index,
exact: Union[bool, str] = "equiv",
check_names: bool = True,
check_less_precise: Union[bool, int] = False,
check_exact: bool = True,
check_categorical: bool = True,
obj: str = "Index",
) -> None:
"""
Check that left and right Index are equal.
Parameters
----------
left : Index
right : Index
exact : bool or {'equiv'}, default 'equiv'
Whether to check the Index class, dtype and inferred_type
are identical. If 'equiv', then RangeIndex can be substituted for
Int64Index as well.
check_names : bool, default True
Whether to check the names attribute.
check_less_precise : bool or int, default False
Specify comparison precision. Only used when check_exact is False.
5 digits (False) or 3 digits (True) after decimal points are compared.
If int, then specify the digits to compare.
check_exact : bool, default True
Whether to compare number exactly.
check_categorical : bool, default True
Whether to compare internal Categorical exactly.
obj : str, default 'Index'
Specify object name being compared, internally used to show appropriate
assertion message.
"""
__tracebackhide__ = True
def _check_types(l, r, obj="Index"):
if exact:
assert_class_equal(l, r, exact=exact, obj=obj)
# Skip exact dtype checking when `check_categorical` is False
if check_categorical:
assert_attr_equal("dtype", l, r, obj=obj)
# allow string-like to have different inferred_types
if l.inferred_type in ("string"):
assert r.inferred_type in ("string")
else:
assert_attr_equal("inferred_type", l, r, obj=obj)
def _get_ilevel_values(index, level):
# accept level number only
unique = index.levels[level]
level_codes = index.codes[level]
filled = take_1d(unique._values, level_codes, fill_value=unique._na_value)
values = unique._shallow_copy(filled, name=index.names[level])
return values
# instance validation
_check_isinstance(left, right, Index)
# class / dtype comparison
_check_types(left, right, obj=obj)
# level comparison
if left.nlevels != right.nlevels:
msg1 = f"{obj} levels are different"
msg2 = f"{left.nlevels}, {left}"
msg3 = f"{right.nlevels}, {right}"
raise_assert_detail(obj, msg1, msg2, msg3)
# length comparison
if len(left) != len(right):
msg1 = f"{obj} length are different"
msg2 = f"{len(left)}, {left}"
msg3 = f"{len(right)}, {right}"
raise_assert_detail(obj, msg1, msg2, msg3)
# MultiIndex special comparison for little-friendly error messages
if left.nlevels > 1:
left = cast(MultiIndex, left)
right = cast(MultiIndex, right)
for level in range(left.nlevels):
# cannot use get_level_values here because it can change dtype
llevel = _get_ilevel_values(left, level)
rlevel = _get_ilevel_values(right, level)
lobj = f"MultiIndex level [{level}]"
assert_index_equal(
llevel,
rlevel,
exact=exact,
check_names=check_names,
check_less_precise=check_less_precise,
check_exact=check_exact,
obj=lobj,
)
# get_level_values may change dtype
_check_types(left.levels[level], right.levels[level], obj=obj)
# skip exact index checking when `check_categorical` is False
if check_exact and check_categorical:
if not left.equals(right):
diff = np.sum((left.values != right.values).astype(int)) * 100.0 / len(left)
msg = f"{obj} values are different ({np.round(diff, 5)} %)"
raise_assert_detail(obj, msg, left, right)
else:
_testing.assert_almost_equal(
left.values,
right.values,
check_less_precise=check_less_precise,
check_dtype=exact,
obj=obj,
lobj=left,
robj=right,
)
# metadata comparison
if check_names:
assert_attr_equal("names", left, right, obj=obj)
if isinstance(left, pd.PeriodIndex) or isinstance(right, pd.PeriodIndex):
assert_attr_equal("freq", left, right, obj=obj)
if isinstance(left, pd.IntervalIndex) or isinstance(right, pd.IntervalIndex):
assert_interval_array_equal(left.values, right.values)
if check_categorical:
if is_categorical_dtype(left) or is_categorical_dtype(right):
assert_categorical_equal(left.values, right.values, obj=f"{obj} category")
def assert_class_equal(left, right, exact: Union[bool, str] = True, obj="Input"):
"""
Checks classes are equal.
"""
__tracebackhide__ = True
def repr_class(x):
if isinstance(x, Index):
# return Index as it is to include values in the error message
return x
try:
return type(x).__name__
except AttributeError:
return repr(type(x))
if exact == "equiv":
if type(left) != type(right):
# allow equivalence of Int64Index/RangeIndex
types = {type(left).__name__, type(right).__name__}
if len(types - {"Int64Index", "RangeIndex"}):
msg = f"{obj} classes are not equivalent"
raise_assert_detail(obj, msg, repr_class(left), repr_class(right))
elif exact:
if type(left) != type(right):
msg = f"{obj} classes are different"
raise_assert_detail(obj, msg, repr_class(left), repr_class(right))
def assert_attr_equal(attr, left, right, obj="Attributes"):
"""
checks attributes are equal. Both objects must have attribute.
Parameters
----------
attr : str
Attribute name being compared.
left : object
right : object
obj : str, default 'Attributes'
Specify object name being compared, internally used to show appropriate
assertion message
"""
__tracebackhide__ = True
left_attr = getattr(left, attr)
right_attr = getattr(right, attr)
if left_attr is right_attr:
return True
elif (
is_number(left_attr)
and np.isnan(left_attr)
and is_number(right_attr)
and np.isnan(right_attr)
):
# np.nan
return True
try:
result = left_attr == right_attr
except TypeError:
# datetimetz on rhs may raise TypeError
result = False
if not isinstance(result, bool):
result = result.all()
if result:
return True
else:
msg = f'Attribute "{attr}" are different'
raise_assert_detail(obj, msg, left_attr, right_attr)
def assert_is_valid_plot_return_object(objs):
import matplotlib.pyplot as plt
if isinstance(objs, (pd.Series, np.ndarray)):
for el in objs.ravel():
msg = (
"one of 'objs' is not a matplotlib Axes instance, "
f"type encountered {repr(type(el).__name__)}"
)
assert isinstance(el, (plt.Axes, dict)), msg
else:
msg = (
"objs is neither an ndarray of Artist instances nor a single "
"ArtistArtist instance, tuple, or dict, 'objs' is a "
f"{repr(type(objs).__name__)}"
)
assert isinstance(objs, (plt.Artist, tuple, dict)), msg
def isiterable(obj):
return hasattr(obj, "__iter__")
def assert_is_sorted(seq):
"""Assert that the sequence is sorted."""
if isinstance(seq, (Index, Series)):
seq = seq.values
# sorting does not change precisions
assert_numpy_array_equal(seq, np.sort(np.array(seq)))
def assert_categorical_equal(
left, right, check_dtype=True, check_category_order=True, obj="Categorical"
):
"""
Test that Categoricals are equivalent.
Parameters
----------
left : Categorical
right : Categorical
check_dtype : bool, default True
Check that integer dtype of the codes are the same
check_category_order : bool, default True
Whether the order of the categories should be compared, which
implies identical integer codes. If False, only the resulting
values are compared. The ordered attribute is
checked regardless.
obj : str, default 'Categorical'
Specify object name being compared, internally used to show appropriate
assertion message
"""
_check_isinstance(left, right, Categorical)
if check_category_order:
assert_index_equal(left.categories, right.categories, obj=f"{obj}.categories")
assert_numpy_array_equal(
left.codes, right.codes, check_dtype=check_dtype, obj=f"{obj}.codes",
)
else:
assert_index_equal(
left.categories.sort_values(),
right.categories.sort_values(),
obj=f"{obj}.categories",
)
assert_index_equal(
left.categories.take(left.codes),
right.categories.take(right.codes),
obj=f"{obj}.values",
)
assert_attr_equal("ordered", left, right, obj=obj)
def assert_interval_array_equal(left, right, exact="equiv", obj="IntervalArray"):
"""
Test that two IntervalArrays are equivalent.
Parameters
----------
left, right : IntervalArray
The IntervalArrays to compare.
exact : bool or {'equiv'}, default 'equiv'
Whether to check the Index class, dtype and inferred_type
are identical. If 'equiv', then RangeIndex can be substituted for
Int64Index as well.
obj : str, default 'IntervalArray'
Specify object name being compared, internally used to show appropriate
assertion message
"""
_check_isinstance(left, right, IntervalArray)
assert_index_equal(left.left, right.left, exact=exact, obj=f"{obj}.left")
assert_index_equal(left.right, right.right, exact=exact, obj=f"{obj}.left")
assert_attr_equal("closed", left, right, obj=obj)
def assert_period_array_equal(left, right, obj="PeriodArray"):
_check_isinstance(left, right, PeriodArray)
assert_numpy_array_equal(left._data, right._data, obj=f"{obj}.values")
assert_attr_equal("freq", left, right, obj=obj)
def assert_datetime_array_equal(left, right, obj="DatetimeArray"):
__tracebackhide__ = True
_check_isinstance(left, right, DatetimeArray)
assert_numpy_array_equal(left._data, right._data, obj=f"{obj}._data")
assert_attr_equal("freq", left, right, obj=obj)
assert_attr_equal("tz", left, right, obj=obj)
def assert_timedelta_array_equal(left, right, obj="TimedeltaArray"):
__tracebackhide__ = True
_check_isinstance(left, right, TimedeltaArray)
assert_numpy_array_equal(left._data, right._data, obj=f"{obj}._data")
assert_attr_equal("freq", left, right, obj=obj)
def raise_assert_detail(obj, message, left, right, diff=None):
__tracebackhide__ = True
if isinstance(left, np.ndarray):
left = pprint_thing(left)
elif is_categorical_dtype(left):
left = repr(left)
if isinstance(right, np.ndarray):
right = pprint_thing(right)
elif is_categorical_dtype(right):
right = repr(right)
msg = f"""{obj} are different
{message}
[left]: {left}
[right]: {right}"""
if diff is not None:
msg += f"\n[diff]: {diff}"
raise AssertionError(msg)
def assert_numpy_array_equal(
left,
right,
strict_nan=False,
check_dtype=True,
err_msg=None,
check_same=None,
obj="numpy array",
):
"""
Check that 'np.ndarray' is equivalent.
Parameters
----------
left, right : numpy.ndarray or iterable
The two arrays to be compared.
strict_nan : bool, default False
If True, consider NaN and None to be different.
check_dtype : bool, default True
Check dtype if both a and b are np.ndarray.
err_msg : str, default None
If provided, used as assertion message.
check_same : None|'copy'|'same', default None
Ensure left and right refer/do not refer to the same memory area.
obj : str, default 'numpy array'
Specify object name being compared, internally used to show appropriate
assertion message.
"""
__tracebackhide__ = True
# instance validation
# Show a detailed error message when classes are different
assert_class_equal(left, right, obj=obj)
# both classes must be an np.ndarray
_check_isinstance(left, right, np.ndarray)
def _get_base(obj):
return obj.base if getattr(obj, "base", None) is not None else obj
left_base = _get_base(left)
right_base = _get_base(right)
if check_same == "same":
if left_base is not right_base:
raise AssertionError(f"{repr(left_base)} is not {repr(right_base)}")
elif check_same == "copy":
if left_base is right_base:
raise AssertionError(f"{repr(left_base)} is {repr(right_base)}")
def _raise(left, right, err_msg):
if err_msg is None:
if left.shape != right.shape:
raise_assert_detail(
obj, f"{obj} shapes are different", left.shape, right.shape,
)
diff = 0
for l, r in zip(left, right):
# count up differences
if not array_equivalent(l, r, strict_nan=strict_nan):
diff += 1
diff = diff * 100.0 / left.size
msg = f"{obj} values are different ({np.round(diff, 5)} %)"
raise_assert_detail(obj, msg, left, right)
raise AssertionError(err_msg)
# compare shape and values
if not array_equivalent(left, right, strict_nan=strict_nan):
_raise(left, right, err_msg)
if check_dtype:
if isinstance(left, np.ndarray) and isinstance(right, np.ndarray):
assert_attr_equal("dtype", left, right, obj=obj)
def assert_extension_array_equal(
left, right, check_dtype=True, check_less_precise=False, check_exact=False
):
"""
Check that left and right ExtensionArrays are equal.
Parameters
----------
left, right : ExtensionArray
The two arrays to compare.
check_dtype : bool, default True
Whether to check if the ExtensionArray dtypes are identical.
check_less_precise : bool or int, default False
Specify comparison precision. Only used when check_exact is False.
5 digits (False) or 3 digits (True) after decimal points are compared.
If int, then specify the digits to compare.
check_exact : bool, default False
Whether to compare number exactly.
Notes
-----
Missing values are checked separately from valid values.
A mask of missing values is computed for each and checked to match.
The remaining all-valid values are cast to object dtype and checked.
"""
assert isinstance(left, ExtensionArray), "left is not an ExtensionArray"
assert isinstance(right, ExtensionArray), "right is not an ExtensionArray"
if check_dtype:
assert_attr_equal("dtype", left, right, obj="ExtensionArray")
if hasattr(left, "asi8") and type(right) == type(left):
# Avoid slow object-dtype comparisons
assert_numpy_array_equal(left.asi8, right.asi8)
return
left_na = np.asarray(left.isna())
right_na = np.asarray(right.isna())
assert_numpy_array_equal(left_na, right_na, obj="ExtensionArray NA mask")
left_valid = np.asarray(left[~left_na].astype(object))
right_valid = np.asarray(right[~right_na].astype(object))
if check_exact:
assert_numpy_array_equal(left_valid, right_valid, obj="ExtensionArray")
else:
_testing.assert_almost_equal(
left_valid,
right_valid,
check_dtype=check_dtype,
check_less_precise=check_less_precise,
obj="ExtensionArray",
)
# This could be refactored to use the NDFrame.equals method
def assert_series_equal(
left,
right,
check_dtype=True,
check_index_type="equiv",
check_series_type=True,
check_less_precise=False,
check_names=True,
check_exact=False,
check_datetimelike_compat=False,
check_categorical=True,
check_category_order=True,
obj="Series",
):
"""
Check that left and right Series are equal.
Parameters
----------
left : Series
right : Series
check_dtype : bool, default True
Whether to check the Series dtype is identical.
check_index_type : bool or {'equiv'}, default 'equiv'
Whether to check the Index class, dtype and inferred_type
are identical.
check_series_type : bool, default True
Whether to check the Series class is identical.
check_less_precise : bool or int, default False
Specify comparison precision. Only used when check_exact is False.
5 digits (False) or 3 digits (True) after decimal points are compared.
If int, then specify the digits to compare.
When comparing two numbers, if the first number has magnitude less
than 1e-5, we compare the two numbers directly and check whether
they are equivalent within the specified precision. Otherwise, we
compare the **ratio** of the second number to the first number and
check whether it is equivalent to 1 within the specified precision.
check_names : bool, default True
Whether to check the Series and Index names attribute.
check_exact : bool, default False
Whether to compare number exactly.
check_datetimelike_compat : bool, default False
Compare datetime-like which is comparable ignoring dtype.
check_categorical : bool, default True
Whether to compare internal Categorical exactly.
check_category_order : bool, default True
Whether to compare category order of internal Categoricals
.. versionadded:: 1.0.2
obj : str, default 'Series'
Specify object name being compared, internally used to show appropriate
assertion message.
"""
__tracebackhide__ = True
# instance validation
_check_isinstance(left, right, Series)
if check_series_type:
# ToDo: There are some tests using rhs is sparse
# lhs is dense. Should use assert_class_equal in future
assert isinstance(left, type(right))
# assert_class_equal(left, right, obj=obj)
# length comparison
if len(left) != len(right):
msg1 = f"{len(left)}, {left.index}"
msg2 = f"{len(right)}, {right.index}"
raise_assert_detail(obj, "Series length are different", msg1, msg2)
# index comparison
assert_index_equal(
left.index,
right.index,
exact=check_index_type,
check_names=check_names,
check_less_precise=check_less_precise,
check_exact=check_exact,
check_categorical=check_categorical,
obj=f"{obj}.index",
)
if check_dtype:
# We want to skip exact dtype checking when `check_categorical`
# is False. We'll still raise if only one is a `Categorical`,
# regardless of `check_categorical`
if (
is_categorical_dtype(left)
and is_categorical_dtype(right)
and not check_categorical
):
pass
else:
assert_attr_equal("dtype", left, right, obj=f"Attributes of {obj}")
if check_exact:
assert_numpy_array_equal(
left._internal_get_values(),
right._internal_get_values(),
check_dtype=check_dtype,
obj=str(obj),
)
elif check_datetimelike_compat:
# we want to check only if we have compat dtypes
# e.g. integer and M|m are NOT compat, but we can simply check
# the values in that case
if needs_i8_conversion(left) or needs_i8_conversion(right):
# datetimelike may have different objects (e.g. datetime.datetime
# vs Timestamp) but will compare equal
if not Index(left.values).equals(Index(right.values)):
msg = (
f"[datetimelike_compat=True] {left.values} "
f"is not equal to {right.values}."
)
raise AssertionError(msg)
else:
assert_numpy_array_equal(
left._internal_get_values(),
right._internal_get_values(),
check_dtype=check_dtype,
)
elif is_interval_dtype(left) or is_interval_dtype(right):
assert_interval_array_equal(left.array, right.array)
elif is_extension_array_dtype(left.dtype) and is_datetime64tz_dtype(left.dtype):
# .values is an ndarray, but ._values is the ExtensionArray.
# TODO: Use .array
assert is_extension_array_dtype(right.dtype)
assert_extension_array_equal(left._values, right._values)
elif (
is_extension_array_dtype(left)
and not is_categorical_dtype(left)
and is_extension_array_dtype(right)
and not is_categorical_dtype(right)
):
assert_extension_array_equal(left.array, right.array)
else:
_testing.assert_almost_equal(
left._internal_get_values(),
right._internal_get_values(),
check_less_precise=check_less_precise,
check_dtype=check_dtype,
obj=str(obj),
)
# metadata comparison
if check_names:
assert_attr_equal("name", left, right, obj=obj)
if check_categorical:
if is_categorical_dtype(left) or is_categorical_dtype(right):
assert_categorical_equal(
left.values,
right.values,
obj=f"{obj} category",
check_category_order=check_category_order,
)
# This could be refactored to use the NDFrame.equals method
def assert_frame_equal(
left,
right,
check_dtype=True,
check_index_type="equiv",
check_column_type="equiv",
check_frame_type=True,
check_less_precise=False,
check_names=True,
by_blocks=False,
check_exact=False,
check_datetimelike_compat=False,
check_categorical=True,
check_like=False,
obj="DataFrame",
):
"""
Check that left and right DataFrame are equal.
This function is intended to compare two DataFrames and output any
differences. Is is mostly intended for use in unit tests.
Additional parameters allow varying the strictness of the
equality checks performed.
Parameters
----------
left : DataFrame
First DataFrame to compare.
right : DataFrame
Second DataFrame to compare.
check_dtype : bool, default True
Whether to check the DataFrame dtype is identical.
check_index_type : bool or {'equiv'}, default 'equiv'
Whether to check the Index class, dtype and inferred_type
are identical.
check_column_type : bool or {'equiv'}, default 'equiv'
Whether to check the columns class, dtype and inferred_type
are identical. Is passed as the ``exact`` argument of
:func:`assert_index_equal`.
check_frame_type : bool, default True
Whether to check the DataFrame class is identical.
check_less_precise : bool or int, default False
Specify comparison precision. Only used when check_exact is False.
5 digits (False) or 3 digits (True) after decimal points are compared.
If int, then specify the digits to compare.
When comparing two numbers, if the first number has magnitude less
than 1e-5, we compare the two numbers directly and check whether
they are equivalent within the specified precision. Otherwise, we
compare the **ratio** of the second number to the first number and
check whether it is equivalent to 1 within the specified precision.
check_names : bool, default True
Whether to check that the `names` attribute for both the `index`
and `column` attributes of the DataFrame is identical.
by_blocks : bool, default False
Specify how to compare internal data. If False, compare by columns.
If True, compare by blocks.
check_exact : bool, default False
Whether to compare number exactly.
check_datetimelike_compat : bool, default False
Compare datetime-like which is comparable ignoring dtype.
check_categorical : bool, default True
Whether to compare internal Categorical exactly.
check_like : bool, default False
If True, ignore the order of index & columns.
Note: index labels must match their respective rows
(same as in columns) - same labels must be with the same data.
obj : str, default 'DataFrame'
Specify object name being compared, internally used to show appropriate
assertion message.
See Also
--------
assert_series_equal : Equivalent method for asserting Series equality.
DataFrame.equals : Check DataFrame equality.
Examples
--------
This example shows comparing two DataFrames that are equal
but with columns of differing dtypes.
>>> from pandas._testing import assert_frame_equal
>>> df1 = pd.DataFrame({'a': [1, 2], 'b': [3, 4]})
>>> df2 = pd.DataFrame({'a': [1, 2], 'b': [3.0, 4.0]})
df1 equals itself.
>>> assert_frame_equal(df1, df1)
df1 differs from df2 as column 'b' is of a different type.
>>> assert_frame_equal(df1, df2)
Traceback (most recent call last):
...
AssertionError: Attributes of DataFrame.iloc[:, 1] (column name="b") are different
Attribute "dtype" are different
[left]: int64
[right]: float64
Ignore differing dtypes in columns with check_dtype.
>>> assert_frame_equal(df1, df2, check_dtype=False)
"""
__tracebackhide__ = True
# instance validation
_check_isinstance(left, right, DataFrame)
if check_frame_type:
assert isinstance(left, type(right))
# assert_class_equal(left, right, obj=obj)
# shape comparison
if left.shape != right.shape:
raise_assert_detail(
obj, f"{obj} shape mismatch", f"{repr(left.shape)}", f"{repr(right.shape)}",
)
if check_like:
left, right = left.reindex_like(right), right
# index comparison
assert_index_equal(
left.index,
right.index,
exact=check_index_type,
check_names=check_names,
check_less_precise=check_less_precise,
check_exact=check_exact,
check_categorical=check_categorical,
obj=f"{obj}.index",
)
# column comparison
assert_index_equal(
left.columns,
right.columns,
exact=check_column_type,
check_names=check_names,
check_less_precise=check_less_precise,
check_exact=check_exact,
check_categorical=check_categorical,
obj=f"{obj}.columns",
)
# compare by blocks
if by_blocks:
rblocks = right._to_dict_of_blocks()
lblocks = left._to_dict_of_blocks()
for dtype in list(set(list(lblocks.keys()) + list(rblocks.keys()))):
assert dtype in lblocks
assert dtype in rblocks
assert_frame_equal(
lblocks[dtype], rblocks[dtype], check_dtype=check_dtype, obj=obj
)
# compare by columns
else:
for i, col in enumerate(left.columns):
assert col in right
lcol = left.iloc[:, i]
rcol = right.iloc[:, i]
assert_series_equal(
lcol,
rcol,
check_dtype=check_dtype,
check_index_type=check_index_type,
check_less_precise=check_less_precise,
check_exact=check_exact,
check_names=check_names,
check_datetimelike_compat=check_datetimelike_compat,
check_categorical=check_categorical,
obj=f'{obj}.iloc[:, {i}] (column name="{col}")',
)
def assert_equal(left, right, **kwargs):
"""
Wrapper for tm.assert_*_equal to dispatch to the appropriate test function.
Parameters
----------
left, right : Index, Series, DataFrame, ExtensionArray, or np.ndarray
The two items to be compared.
**kwargs
All keyword arguments are passed through to the underlying assert method.
"""
__tracebackhide__ = True
if isinstance(left, pd.Index):
assert_index_equal(left, right, **kwargs)
elif isinstance(left, pd.Series):
assert_series_equal(left, right, **kwargs)
elif isinstance(left, pd.DataFrame):
assert_frame_equal(left, right, **kwargs)
elif isinstance(left, IntervalArray):
assert_interval_array_equal(left, right, **kwargs)
elif isinstance(left, PeriodArray):
assert_period_array_equal(left, right, **kwargs)
elif isinstance(left, DatetimeArray):
assert_datetime_array_equal(left, right, **kwargs)
elif isinstance(left, TimedeltaArray):
assert_timedelta_array_equal(left, right, **kwargs)
elif isinstance(left, ExtensionArray):
assert_extension_array_equal(left, right, **kwargs)
elif isinstance(left, np.ndarray):
assert_numpy_array_equal(left, right, **kwargs)
elif isinstance(left, str):
assert kwargs == {}
assert left == right
else:
raise NotImplementedError(type(left))
def box_expected(expected, box_cls, transpose=True):
"""
Helper function to wrap the expected output of a test in a given box_class.
Parameters
----------
expected : np.ndarray, Index, Series
box_cls : {Index, Series, DataFrame}
Returns
-------
subclass of box_cls
"""
if box_cls is pd.Index:
expected = pd.Index(expected)
elif box_cls is pd.Series:
expected = pd.Series(expected)
elif box_cls is pd.DataFrame:
expected = pd.Series(expected).to_frame()
if transpose:
# for vector operations, we we need a DataFrame to be a single-row,
# not a single-column, in order to operate against non-DataFrame
# vectors of the same length.
expected = expected.T
elif box_cls is PeriodArray:
# the PeriodArray constructor is not as flexible as period_array
expected = period_array(expected)
elif box_cls is DatetimeArray:
expected = DatetimeArray(expected)
elif box_cls is TimedeltaArray:
expected = TimedeltaArray(expected)
elif box_cls is np.ndarray:
expected = np.array(expected)
elif box_cls is to_array:
expected = to_array(expected)
else:
raise NotImplementedError(box_cls)
return expected
def to_array(obj):
# temporary implementation until we get pd.array in place
if is_period_dtype(obj):
return period_array(obj)
elif is_datetime64_dtype(obj) or is_datetime64tz_dtype(obj):
return DatetimeArray._from_sequence(obj)
elif is_timedelta64_dtype(obj):
return TimedeltaArray._from_sequence(obj)
else:
return np.array(obj)
# -----------------------------------------------------------------------------
# Sparse
def assert_sp_array_equal(
left,
right,
check_dtype=True,
check_kind=True,
check_fill_value=True,
consolidate_block_indices=False,
):
"""
Check that the left and right SparseArray are equal.
Parameters
----------
left : SparseArray
right : SparseArray
check_dtype : bool, default True
Whether to check the data dtype is identical.
check_kind : bool, default True
Whether to just the kind of the sparse index for each column.
check_fill_value : bool, default True
Whether to check that left.fill_value matches right.fill_value
consolidate_block_indices : bool, default False
Whether to consolidate contiguous blocks for sparse arrays with
a BlockIndex. Some operations, e.g. concat, will end up with
block indices that could be consolidated. Setting this to true will
create a new BlockIndex for that array, with consolidated
block indices.
"""
_check_isinstance(left, right, pd.arrays.SparseArray)
assert_numpy_array_equal(left.sp_values, right.sp_values, check_dtype=check_dtype)
# SparseIndex comparison
assert isinstance(left.sp_index, pd._libs.sparse.SparseIndex)
assert isinstance(right.sp_index, pd._libs.sparse.SparseIndex)
if not check_kind:
left_index = left.sp_index.to_block_index()
right_index = right.sp_index.to_block_index()
else:
left_index = left.sp_index
right_index = right.sp_index
if consolidate_block_indices and left.kind == "block":
# we'll probably remove this hack...
left_index = left_index.to_int_index().to_block_index()
right_index = right_index.to_int_index().to_block_index()
if not left_index.equals(right_index):
raise_assert_detail(
"SparseArray.index", "index are not equal", left_index, right_index
)
else:
# Just ensure a
pass
if check_fill_value:
assert_attr_equal("fill_value", left, right)
if check_dtype:
assert_attr_equal("dtype", left, right)
assert_numpy_array_equal(left.to_dense(), right.to_dense(), check_dtype=check_dtype)
# -----------------------------------------------------------------------------
# Others
def assert_contains_all(iterable, dic):
for k in iterable:
assert k in dic, f"Did not contain item: {repr(k)}"
def assert_copy(iter1, iter2, **eql_kwargs):
"""
iter1, iter2: iterables that produce elements
comparable with assert_almost_equal
Checks that the elements are equal, but not
the same object. (Does not check that items
in sequences are also not the same object)
"""
for elem1, elem2 in zip(iter1, iter2):
assert_almost_equal(elem1, elem2, **eql_kwargs)
msg = (
f"Expected object {repr(type(elem1))} and object {repr(type(elem2))} to be "
"different objects, but they were the same object."
)
assert elem1 is not elem2, msg
def getCols(k):
return string.ascii_uppercase[:k]
# make index
def makeStringIndex(k=10, name=None):
return Index(rands_array(nchars=10, size=k), name=name)
def makeUnicodeIndex(k=10, name=None):
return Index(randu_array(nchars=10, size=k), name=name)
def makeCategoricalIndex(k=10, n=3, name=None, **kwargs):
""" make a length k index or n categories """
x = rands_array(nchars=4, size=n)
return CategoricalIndex(
Categorical.from_codes(np.arange(k) % n, categories=x), name=name, **kwargs
)
def makeIntervalIndex(k=10, name=None, **kwargs):
""" make a length k IntervalIndex """
x = np.linspace(0, 100, num=(k + 1))
return IntervalIndex.from_breaks(x, name=name, **kwargs)
def makeBoolIndex(k=10, name=None):
if k == 1:
return Index([True], name=name)
elif k == 2:
return Index([False, True], name=name)
return Index([False, True] + [False] * (k - 2), name=name)
def makeIntIndex(k=10, name=None):
return Index(list(range(k)), name=name)
def makeUIntIndex(k=10, name=None):
return Index([2 ** 63 + i for i in range(k)], name=name)
def makeRangeIndex(k=10, name=None, **kwargs):
return RangeIndex(0, k, 1, name=name, **kwargs)
def makeFloatIndex(k=10, name=None):
values = sorted(np.random.random_sample(k)) - np.random.random_sample(1)
return Index(values * (10 ** np.random.randint(0, 9)), name=name)
def makeDateIndex(k=10, freq="B", name=None, **kwargs):
dt = datetime(2000, 1, 1)
dr = bdate_range(dt, periods=k, freq=freq, name=name)
return DatetimeIndex(dr, name=name, **kwargs)
def makeTimedeltaIndex(k=10, freq="D", name=None, **kwargs):
return pd.timedelta_range(start="1 day", periods=k, freq=freq, name=name, **kwargs)
def makePeriodIndex(k=10, name=None, **kwargs):
dt = datetime(2000, 1, 1)
dr = pd.period_range(start=dt, periods=k, freq="B", name=name, **kwargs)
return dr
def makeMultiIndex(k=10, names=None, **kwargs):
return MultiIndex.from_product((("foo", "bar"), (1, 2)), names=names, **kwargs)
_names = [
"Alice",
"Bob",
"Charlie",
"Dan",
"Edith",
"Frank",
"George",
"Hannah",
"Ingrid",
"Jerry",
"Kevin",
"Laura",
"Michael",
"Norbert",
"Oliver",
"Patricia",
"Quinn",
"Ray",
"Sarah",
"Tim",
"Ursula",
"Victor",
"Wendy",
"Xavier",
"Yvonne",
"Zelda",
]
def _make_timeseries(start="2000-01-01", end="2000-12-31", freq="1D", seed=None):
"""
Make a DataFrame with a DatetimeIndex
Parameters
----------
start : str or Timestamp, default "2000-01-01"
The start of the index. Passed to date_range with `freq`.
end : str or Timestamp, default "2000-12-31"
The end of the index. Passed to date_range with `freq`.
freq : str or Freq
The frequency to use for the DatetimeIndex
seed : int, optional
The random state seed.
* name : object dtype with string names
* id : int dtype with
* x, y : float dtype
Examples
--------
>>> _make_timeseries()
id name x y
timestamp
2000-01-01 982 Frank 0.031261 0.986727
2000-01-02 1025 Edith -0.086358 -0.032920
2000-01-03 982 Edith 0.473177 0.298654
2000-01-04 1009 Sarah 0.534344 -0.750377
2000-01-05 963 Zelda -0.271573 0.054424
... ... ... ... ...
2000-12-27 980 Ingrid -0.132333 -0.422195
2000-12-28 972 Frank -0.376007 -0.298687
2000-12-29 1009 Ursula -0.865047 -0.503133
2000-12-30 1000 Hannah -0.063757 -0.507336
2000-12-31 972 Tim -0.869120 0.531685
"""
index = pd.date_range(start=start, end=end, freq=freq, name="timestamp")
n = len(index)
state = np.random.RandomState(seed)
columns = {
"name": state.choice(_names, size=n),
"id": state.poisson(1000, size=n),
"x": state.rand(n) * 2 - 1,
"y": state.rand(n) * 2 - 1,
}
df = pd.DataFrame(columns, index=index, columns=sorted(columns))
if df.index[-1] == end:
df = df.iloc[:-1]
return df
def all_index_generator(k=10):
"""
Generator which can be iterated over to get instances of all the various
index classes.
Parameters
----------
k: length of each of the index instances
"""
all_make_index_funcs = [
makeIntIndex,
makeFloatIndex,
makeStringIndex,
makeUnicodeIndex,
makeDateIndex,
makePeriodIndex,
makeTimedeltaIndex,
makeBoolIndex,
makeRangeIndex,
makeIntervalIndex,
makeCategoricalIndex,
]
for make_index_func in all_make_index_funcs:
yield make_index_func(k=k)
def index_subclass_makers_generator():
make_index_funcs = [
makeDateIndex,
makePeriodIndex,
makeTimedeltaIndex,
makeRangeIndex,
makeIntervalIndex,
makeCategoricalIndex,
makeMultiIndex,
]
for make_index_func in make_index_funcs:
yield make_index_func
def all_timeseries_index_generator(k=10):
"""
Generator which can be iterated over to get instances of all the classes
which represent time-series.
Parameters
----------
k: length of each of the index instances
"""
make_index_funcs = [makeDateIndex, makePeriodIndex, makeTimedeltaIndex]
for make_index_func in make_index_funcs:
yield make_index_func(k=k)
# make series
def makeFloatSeries(name=None):
index = makeStringIndex(N)
return Series(randn(N), index=index, name=name)
def makeStringSeries(name=None):
index = makeStringIndex(N)
return Series(randn(N), index=index, name=name)
def makeObjectSeries(name=None):
data = makeStringIndex(N)
data = Index(data, dtype=object)
index = makeStringIndex(N)
return Series(data, index=index, name=name)
def getSeriesData():
index = makeStringIndex(N)
return {c: Series(randn(N), index=index) for c in getCols(K)}
def makeTimeSeries(nper=None, freq="B", name=None):
if nper is None:
nper = N
return Series(randn(nper), index=makeDateIndex(nper, freq=freq), name=name)
def makePeriodSeries(nper=None, name=None):
if nper is None:
nper = N
return Series(randn(nper), index=makePeriodIndex(nper), name=name)
def getTimeSeriesData(nper=None, freq="B"):
return {c: makeTimeSeries(nper, freq) for c in getCols(K)}
def getPeriodData(nper=None):
return {c: makePeriodSeries(nper) for c in getCols(K)}
# make frame
def makeTimeDataFrame(nper=None, freq="B"):
data = getTimeSeriesData(nper, freq)
return DataFrame(data)
def makeDataFrame():
data = getSeriesData()
return DataFrame(data)
def getMixedTypeDict():
index = Index(["a", "b", "c", "d", "e"])
data = {
"A": [0.0, 1.0, 2.0, 3.0, 4.0],
"B": [0.0, 1.0, 0.0, 1.0, 0.0],
"C": ["foo1", "foo2", "foo3", "foo4", "foo5"],
"D": bdate_range("1/1/2009", periods=5),
}
return index, data
def makeMixedDataFrame():
return DataFrame(getMixedTypeDict()[1])
def makePeriodFrame(nper=None):
data = getPeriodData(nper)
return DataFrame(data)
def makeCustomIndex(
nentries, nlevels, prefix="#", names=False, ndupe_l=None, idx_type=None
):
"""
Create an index/multindex with given dimensions, levels, names, etc'
nentries - number of entries in index
nlevels - number of levels (> 1 produces multindex)
prefix - a string prefix for labels
names - (Optional), bool or list of strings. if True will use default
names, if false will use no names, if a list is given, the name of
each level in the index will be taken from the list.
ndupe_l - (Optional), list of ints, the number of rows for which the
label will repeated at the corresponding level, you can specify just
the first few, the rest will use the default ndupe_l of 1.
len(ndupe_l) <= nlevels.
idx_type - "i"/"f"/"s"/"u"/"dt"/"p"/"td".
If idx_type is not None, `idx_nlevels` must be 1.
"i"/"f" creates an integer/float index,
"s"/"u" creates a string/unicode index
"dt" create a datetime index.
"td" create a datetime index.
if unspecified, string labels will be generated.
"""
if ndupe_l is None:
ndupe_l = [1] * nlevels
assert is_sequence(ndupe_l) and len(ndupe_l) <= nlevels
assert names is None or names is False or names is True or len(names) is nlevels
assert idx_type is None or (
idx_type in ("i", "f", "s", "u", "dt", "p", "td") and nlevels == 1
)
if names is True:
# build default names
names = [prefix + str(i) for i in range(nlevels)]
if names is False:
# pass None to index constructor for no name
names = None
# make singleton case uniform
if isinstance(names, str) and nlevels == 1:
names = [names]
# specific 1D index type requested?
idx_func = dict(
i=makeIntIndex,
f=makeFloatIndex,
s=makeStringIndex,
u=makeUnicodeIndex,
dt=makeDateIndex,
td=makeTimedeltaIndex,
p=makePeriodIndex,
).get(idx_type)
if idx_func:
idx = idx_func(nentries)
# but we need to fill in the name
if names:
idx.name = names[0]
return idx
elif idx_type is not None:
raise ValueError(
f"{repr(idx_type)} is not a legal value for `idx_type`, "
"use 'i'/'f'/'s'/'u'/'dt'/'p'/'td'."
)
if len(ndupe_l) < nlevels:
ndupe_l.extend([1] * (nlevels - len(ndupe_l)))
assert len(ndupe_l) == nlevels
assert all(x > 0 for x in ndupe_l)
tuples = []
for i in range(nlevels):
def keyfunc(x):
import re
numeric_tuple = re.sub(r"[^\d_]_?", "", x).split("_")
return [int(num) for num in numeric_tuple]
# build a list of lists to create the index from
div_factor = nentries // ndupe_l[i] + 1
cnt = Counter()
for j in range(div_factor):
label = f"{prefix}_l{i}_g{j}"
cnt[label] = ndupe_l[i]
# cute Counter trick
result = sorted(cnt.elements(), key=keyfunc)[:nentries]
tuples.append(result)
tuples = list(zip(*tuples))
# convert tuples to index
if nentries == 1:
# we have a single level of tuples, i.e. a regular Index
index = Index(tuples[0], name=names[0])
elif nlevels == 1:
name = None if names is None else names[0]
index = Index((x[0] for x in tuples), name=name)
else:
index = MultiIndex.from_tuples(tuples, names=names)
return index
def makeCustomDataframe(
nrows,
ncols,
c_idx_names=True,
r_idx_names=True,
c_idx_nlevels=1,
r_idx_nlevels=1,
data_gen_f=None,
c_ndupe_l=None,
r_ndupe_l=None,
dtype=None,
c_idx_type=None,
r_idx_type=None,
):
"""
Create a DataFrame using supplied parameters.
Parameters
----------
nrows, ncols - number of data rows/cols
c_idx_names, idx_names - False/True/list of strings, yields No names ,
default names or uses the provided names for the levels of the
corresponding index. You can provide a single string when
c_idx_nlevels ==1.
c_idx_nlevels - number of levels in columns index. > 1 will yield MultiIndex
r_idx_nlevels - number of levels in rows index. > 1 will yield MultiIndex
data_gen_f - a function f(row,col) which return the data value
at that position, the default generator used yields values of the form
"RxCy" based on position.
c_ndupe_l, r_ndupe_l - list of integers, determines the number
of duplicates for each label at a given level of the corresponding
index. The default `None` value produces a multiplicity of 1 across
all levels, i.e. a unique index. Will accept a partial list of length
N < idx_nlevels, for just the first N levels. If ndupe doesn't divide
nrows/ncol, the last label might have lower multiplicity.
dtype - passed to the DataFrame constructor as is, in case you wish to
have more control in conjunction with a custom `data_gen_f`
r_idx_type, c_idx_type - "i"/"f"/"s"/"u"/"dt"/"td".
If idx_type is not None, `idx_nlevels` must be 1.
"i"/"f" creates an integer/float index,
"s"/"u" creates a string/unicode index
"dt" create a datetime index.
"td" create a timedelta index.
if unspecified, string labels will be generated.
Examples
--------
# 5 row, 3 columns, default names on both, single index on both axis
>> makeCustomDataframe(5,3)
# make the data a random int between 1 and 100
>> mkdf(5,3,data_gen_f=lambda r,c:randint(1,100))
# 2-level multiindex on rows with each label duplicated
# twice on first level, default names on both axis, single
# index on both axis
>> a=makeCustomDataframe(5,3,r_idx_nlevels=2,r_ndupe_l=[2])
# DatetimeIndex on row, index with unicode labels on columns
# no names on either axis
>> a=makeCustomDataframe(5,3,c_idx_names=False,r_idx_names=False,
r_idx_type="dt",c_idx_type="u")
# 4-level multindex on rows with names provided, 2-level multindex
# on columns with default labels and default names.
>> a=makeCustomDataframe(5,3,r_idx_nlevels=4,
r_idx_names=["FEE","FI","FO","FAM"],
c_idx_nlevels=2)
>> a=mkdf(5,3,r_idx_nlevels=2,c_idx_nlevels=4)
"""
assert c_idx_nlevels > 0
assert r_idx_nlevels > 0
assert r_idx_type is None or (
r_idx_type in ("i", "f", "s", "u", "dt", "p", "td") and r_idx_nlevels == 1
)
assert c_idx_type is None or (
c_idx_type in ("i", "f", "s", "u", "dt", "p", "td") and c_idx_nlevels == 1
)
columns = makeCustomIndex(
ncols,
nlevels=c_idx_nlevels,
prefix="C",
names=c_idx_names,
ndupe_l=c_ndupe_l,
idx_type=c_idx_type,
)
index = makeCustomIndex(
nrows,
nlevels=r_idx_nlevels,
prefix="R",
names=r_idx_names,
ndupe_l=r_ndupe_l,
idx_type=r_idx_type,
)
# by default, generate data based on location
if data_gen_f is None:
data_gen_f = lambda r, c: f"R{r}C{c}"
data = [[data_gen_f(r, c) for c in range(ncols)] for r in range(nrows)]
return DataFrame(data, index, columns, dtype=dtype)
def _create_missing_idx(nrows, ncols, density, random_state=None):
if random_state is None:
random_state = np.random
else:
random_state = np.random.RandomState(random_state)
# below is cribbed from scipy.sparse
size = int(np.round((1 - density) * nrows * ncols))
# generate a few more to ensure unique values
min_rows = 5
fac = 1.02
extra_size = min(size + min_rows, fac * size)
def _gen_unique_rand(rng, _extra_size):
ind = rng.rand(int(_extra_size))
return np.unique(np.floor(ind * nrows * ncols))[:size]
ind = _gen_unique_rand(random_state, extra_size)
while ind.size < size:
extra_size *= 1.05
ind = _gen_unique_rand(random_state, extra_size)
j = np.floor(ind * 1.0 / nrows).astype(int)
i = (ind - j * nrows).astype(int)
return i.tolist(), j.tolist()
def makeMissingCustomDataframe(
nrows,
ncols,
density=0.9,
random_state=None,
c_idx_names=True,
r_idx_names=True,
c_idx_nlevels=1,
r_idx_nlevels=1,
data_gen_f=None,
c_ndupe_l=None,
r_ndupe_l=None,
dtype=None,
c_idx_type=None,
r_idx_type=None,
):
"""
Parameters
----------
Density : float, optional
Float in (0, 1) that gives the percentage of non-missing numbers in
the DataFrame.
random_state : {np.random.RandomState, int}, optional
Random number generator or random seed.
See makeCustomDataframe for descriptions of the rest of the parameters.
"""
df = makeCustomDataframe(
nrows,
ncols,
c_idx_names=c_idx_names,
r_idx_names=r_idx_names,
c_idx_nlevels=c_idx_nlevels,
r_idx_nlevels=r_idx_nlevels,
data_gen_f=data_gen_f,
c_ndupe_l=c_ndupe_l,
r_ndupe_l=r_ndupe_l,
dtype=dtype,
c_idx_type=c_idx_type,
r_idx_type=r_idx_type,
)
i, j = _create_missing_idx(nrows, ncols, density, random_state)
df.values[i, j] = np.nan
return df
def makeMissingDataframe(density=0.9, random_state=None):
df = makeDataFrame()
i, j = _create_missing_idx(*df.shape, density=density, random_state=random_state)
df.values[i, j] = np.nan
return df
def optional_args(decorator):
"""
allows a decorator to take optional positional and keyword arguments.
Assumes that taking a single, callable, positional argument means that
it is decorating a function, i.e. something like this::
@my_decorator
def function(): pass
Calls decorator with decorator(f, *args, **kwargs)
"""
@wraps(decorator)
def wrapper(*args, **kwargs):
def dec(f):
return decorator(f, *args, **kwargs)
is_decorating = not kwargs and len(args) == 1 and callable(args[0])
if is_decorating:
f = args[0]
args = []
return dec(f)
else:
return dec
return wrapper
# skip tests on exceptions with this message
_network_error_messages = (
# 'urlopen error timed out',
# 'timeout: timed out',
# 'socket.timeout: timed out',
"timed out",
"Server Hangup",
"HTTP Error 503: Service Unavailable",
"502: Proxy Error",
"HTTP Error 502: internal error",
"HTTP Error 502",
"HTTP Error 503",
"HTTP Error 403",
"HTTP Error 400",
"Temporary failure in name resolution",
"Name or service not known",
"Connection refused",
"certificate verify",
)
# or this e.errno/e.reason.errno
_network_errno_vals = (
101, # Network is unreachable
111, # Connection refused
110, # Connection timed out
104, # Connection reset Error
54, # Connection reset by peer
60, # urllib.error.URLError: [Errno 60] Connection timed out
)
# Both of the above shouldn't mask real issues such as 404's
# or refused connections (changed DNS).
# But some tests (test_data yahoo) contact incredibly flakey
# servers.
# and conditionally raise on exception types in _get_default_network_errors
def _get_default_network_errors():
# Lazy import for http.client because it imports many things from the stdlib
import http.client
return (IOError, http.client.HTTPException, TimeoutError)
def can_connect(url, error_classes=None):
"""
Try to connect to the given url. True if succeeds, False if IOError
raised
Parameters
----------
url : basestring
The URL to try to connect to
Returns
-------
connectable : bool
Return True if no IOError (unable to connect) or URLError (bad url) was
raised
"""
if error_classes is None:
error_classes = _get_default_network_errors()
try:
with urlopen(url):
pass
except error_classes:
return False
else:
return True
@optional_args
def network(
t,
url="http://www.google.com",
raise_on_error=_RAISE_NETWORK_ERROR_DEFAULT,
check_before_test=False,
error_classes=None,
skip_errnos=_network_errno_vals,
_skip_on_messages=_network_error_messages,
):
"""
Label a test as requiring network connection and, if an error is
encountered, only raise if it does not find a network connection.
In comparison to ``network``, this assumes an added contract to your test:
you must assert that, under normal conditions, your test will ONLY fail if
it does not have network connectivity.
You can call this in 3 ways: as a standard decorator, with keyword
arguments, or with a positional argument that is the url to check.
Parameters
----------
t : callable
The test requiring network connectivity.
url : path
The url to test via ``pandas.io.common.urlopen`` to check
for connectivity. Defaults to 'http://www.google.com'.
raise_on_error : bool
If True, never catches errors.
check_before_test : bool
If True, checks connectivity before running the test case.
error_classes : tuple or Exception
error classes to ignore. If not in ``error_classes``, raises the error.
defaults to IOError. Be careful about changing the error classes here.
skip_errnos : iterable of int
Any exception that has .errno or .reason.erno set to one
of these values will be skipped with an appropriate
message.
_skip_on_messages: iterable of string
any exception e for which one of the strings is
a substring of str(e) will be skipped with an appropriate
message. Intended to suppress errors where an errno isn't available.
Notes
-----
* ``raise_on_error`` supercedes ``check_before_test``
Returns
-------
t : callable
The decorated test ``t``, with checks for connectivity errors.
Example
-------
Tests decorated with @network will fail if it's possible to make a network
connection to another URL (defaults to google.com)::
>>> from pandas._testing import network
>>> from pandas.io.common import urlopen
>>> @network
... def test_network():
... with urlopen("rabbit://bonanza.com"):
... pass
Traceback
...
URLError: <urlopen error unknown url type: rabit>
You can specify alternative URLs::
>>> @network("http://www.yahoo.com")
... def test_something_with_yahoo():
... raise IOError("Failure Message")
>>> test_something_with_yahoo()
Traceback (most recent call last):
...
IOError: Failure Message
If you set check_before_test, it will check the url first and not run the
test on failure::
>>> @network("failing://url.blaher", check_before_test=True)
... def test_something():
... print("I ran!")
... raise ValueError("Failure")
>>> test_something()
Traceback (most recent call last):
...
Errors not related to networking will always be raised.
"""
from pytest import skip
if error_classes is None:
error_classes = _get_default_network_errors()
t.network = True
@wraps(t)
def wrapper(*args, **kwargs):
if check_before_test and not raise_on_error:
if not can_connect(url, error_classes):
skip()
try:
return t(*args, **kwargs)
except Exception as err:
errno = getattr(err, "errno", None)
if not errno and hasattr(errno, "reason"):
errno = getattr(err.reason, "errno", None)
if errno in skip_errnos:
skip(f"Skipping test due to known errno and error {err}")
e_str = str(err)
if any(m.lower() in e_str.lower() for m in _skip_on_messages):
skip(
f"Skipping test because exception message is known and error {err}"
)
if not isinstance(err, error_classes):
raise
if raise_on_error or can_connect(url, error_classes):
raise
else:
skip(f"Skipping test due to lack of connectivity and error {err}")
return wrapper
with_connectivity_check = network
@contextmanager
def assert_produces_warning(
expected_warning=Warning,
filter_level="always",
clear=None,
check_stacklevel=True,
raise_on_extra_warnings=True,
):
"""
Context manager for running code expected to either raise a specific
warning, or not raise any warnings. Verifies that the code raises the
expected warning, and that it does not raise any other unexpected
warnings. It is basically a wrapper around ``warnings.catch_warnings``.
Parameters
----------
expected_warning : {Warning, False, None}, default Warning
The type of Exception raised. ``exception.Warning`` is the base
class for all warnings. To check that no warning is returned,
specify ``False`` or ``None``.
filter_level : str or None, default "always"
Specifies whether warnings are ignored, displayed, or turned
into errors.
Valid values are:
* "error" - turns matching warnings into exceptions
* "ignore" - discard the warning
* "always" - always emit a warning
* "default" - print the warning the first time it is generated
from each location
* "module" - print the warning the first time it is generated
from each module
* "once" - print the warning the first time it is generated
clear : str, default None
If not ``None`` then remove any previously raised warnings from
the ``__warningsregistry__`` to ensure that no warning messages are
suppressed by this context manager. If ``None`` is specified,
the ``__warningsregistry__`` keeps track of which warnings have been
shown, and does not show them again.
check_stacklevel : bool, default True
If True, displays the line that called the function containing
the warning to show were the function is called. Otherwise, the
line that implements the function is displayed.
raise_on_extra_warnings : bool, default True
Whether extra warnings not of the type `expected_warning` should
cause the test to fail.
Examples
--------
>>> import warnings
>>> with assert_produces_warning():
... warnings.warn(UserWarning())
...
>>> with assert_produces_warning(False):
... warnings.warn(RuntimeWarning())
...
Traceback (most recent call last):
...
AssertionError: Caused unexpected warning(s): ['RuntimeWarning'].
>>> with assert_produces_warning(UserWarning):
... warnings.warn(RuntimeWarning())
Traceback (most recent call last):
...
AssertionError: Did not see expected warning of class 'UserWarning'.
..warn:: This is *not* thread-safe.
"""
__tracebackhide__ = True
with warnings.catch_warnings(record=True) as w:
if clear is not None:
# make sure that we are clearing these warnings
# if they have happened before
# to guarantee that we will catch them
if not is_list_like(clear):
clear = [clear]
for m in clear:
try:
m.__warningregistry__.clear()
except AttributeError:
# module may not have __warningregistry__
pass
saw_warning = False
warnings.simplefilter(filter_level)
yield w
extra_warnings = []
for actual_warning in w:
if expected_warning and issubclass(
actual_warning.category, expected_warning
):
saw_warning = True
if check_stacklevel and issubclass(
actual_warning.category, (FutureWarning, DeprecationWarning)
):
from inspect import getframeinfo, stack
caller = getframeinfo(stack()[2][0])
msg = (
"Warning not set with correct stacklevel. "
f"File where warning is raised: {actual_warning.filename} != "
f"{caller.filename}. Warning message: {actual_warning.message}"
)
assert actual_warning.filename == caller.filename, msg
else:
extra_warnings.append(
(
actual_warning.category.__name__,
actual_warning.message,
actual_warning.filename,
actual_warning.lineno,
)
)
if expected_warning:
msg = (
f"Did not see expected warning of class "
f"{repr(expected_warning.__name__)}"
)
assert saw_warning, msg
if raise_on_extra_warnings and extra_warnings:
raise AssertionError(
f"Caused unexpected warning(s): {repr(extra_warnings)}"
)
class RNGContext:
"""
Context manager to set the numpy random number generator speed. Returns
to the original value upon exiting the context manager.
Parameters
----------
seed : int
Seed for numpy.random.seed
Examples
--------
with RNGContext(42):
np.random.randn()
"""
def __init__(self, seed):
self.seed = seed
def __enter__(self):
self.start_state = np.random.get_state()
np.random.seed(self.seed)
def __exit__(self, exc_type, exc_value, traceback):
np.random.set_state(self.start_state)
@contextmanager
def with_csv_dialect(name, **kwargs):
"""
Context manager to temporarily register a CSV dialect for parsing CSV.
Parameters
----------
name : str
The name of the dialect.
kwargs : mapping
The parameters for the dialect.
Raises
------
ValueError : the name of the dialect conflicts with a builtin one.
See Also
--------
csv : Python's CSV library.
"""
import csv
_BUILTIN_DIALECTS = {"excel", "excel-tab", "unix"}
if name in _BUILTIN_DIALECTS:
raise ValueError("Cannot override builtin dialect.")
csv.register_dialect(name, **kwargs)
yield
csv.unregister_dialect(name)
@contextmanager
def use_numexpr(use, min_elements=None):
from pandas.core.computation import expressions as expr
if min_elements is None:
min_elements = expr._MIN_ELEMENTS
olduse = expr._USE_NUMEXPR
oldmin = expr._MIN_ELEMENTS
expr.set_use_numexpr(use)
expr._MIN_ELEMENTS = min_elements
yield
expr._MIN_ELEMENTS = oldmin
expr.set_use_numexpr(olduse)
def test_parallel(num_threads=2, kwargs_list=None):
"""
Decorator to run the same function multiple times in parallel.
Parameters
----------
num_threads : int, optional
The number of times the function is run in parallel.
kwargs_list : list of dicts, optional
The list of kwargs to update original
function kwargs on different threads.
Notes
-----
This decorator does not pass the return value of the decorated function.
Original from scikit-image:
https://github.com/scikit-image/scikit-image/pull/1519
"""
assert num_threads > 0
has_kwargs_list = kwargs_list is not None
if has_kwargs_list:
assert len(kwargs_list) == num_threads
import threading
def wrapper(func):
@wraps(func)
def inner(*args, **kwargs):
if has_kwargs_list:
update_kwargs = lambda i: dict(kwargs, **kwargs_list[i])
else:
update_kwargs = lambda i: kwargs
threads = []
for i in range(num_threads):
updated_kwargs = update_kwargs(i)
thread = threading.Thread(target=func, args=args, kwargs=updated_kwargs)
threads.append(thread)
for thread in threads:
thread.start()
for thread in threads:
thread.join()
return inner
return wrapper
class SubclassedSeries(Series):
_metadata = ["testattr", "name"]
@property
def _constructor(self):
return SubclassedSeries
@property
def _constructor_expanddim(self):
return SubclassedDataFrame
class SubclassedDataFrame(DataFrame):
_metadata = ["testattr"]
@property
def _constructor(self):
return SubclassedDataFrame
@property
def _constructor_sliced(self):
return SubclassedSeries
class SubclassedCategorical(Categorical):
@property
def _constructor(self):
return SubclassedCategorical
@contextmanager
def set_timezone(tz: str):
"""
Context manager for temporarily setting a timezone.
Parameters
----------
tz : str
A string representing a valid timezone.
Examples
--------
>>> from datetime import datetime
>>> from dateutil.tz import tzlocal
>>> tzlocal().tzname(datetime.now())
'IST'
>>> with set_timezone('US/Eastern'):
... tzlocal().tzname(datetime.now())
...
'EDT'
"""
import os
import time
def setTZ(tz):
if tz is None:
try:
del os.environ["TZ"]
except KeyError:
pass
else:
os.environ["TZ"] = tz
time.tzset()
orig_tz = os.environ.get("TZ")
setTZ(tz)
try:
yield
finally:
setTZ(orig_tz)
def _make_skipna_wrapper(alternative, skipna_alternative=None):
"""
Create a function for calling on an array.
Parameters
----------
alternative : function
The function to be called on the array with no NaNs.
Only used when 'skipna_alternative' is None.
skipna_alternative : function
The function to be called on the original array
Returns
-------
function
"""
if skipna_alternative:
def skipna_wrapper(x):
return skipna_alternative(x.values)
else:
def skipna_wrapper(x):
nona = x.dropna()
if len(nona) == 0:
return np.nan
return alternative(nona)
return skipna_wrapper
def convert_rows_list_to_csv_str(rows_list: List[str]):
"""
Convert list of CSV rows to single CSV-formatted string for current OS.
This method is used for creating expected value of to_csv() method.
Parameters
----------
rows_list : List[str]
Each element represents the row of csv.
Returns
-------
str
Expected output of to_csv() in current OS.
"""
sep = os.linesep
expected = sep.join(rows_list) + sep
return expected
def external_error_raised(
expected_exception: Type[Exception],
) -> Callable[[Type[Exception], None], None]:
"""
Helper function to mark pytest.raises that have an external error message.
Parameters
----------
expected_exception : Exception
Expected error to raise.
Returns
-------
Callable
Regular `pytest.raises` function with `match` equal to `None`.
"""
import pytest
return pytest.raises(expected_exception, match=None)
| BugsInPy/BugsInPy/temp/projects/pandas/bug-57-fixed/pandas/pandas/_testing.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-57-buggy/pandas/pandas/_testing.py |
pandas-bug-69 | from typing import Hashable, List, Tuple, Union
import numpy as np
from pandas._libs.indexing import _NDFrameIndexerBase
from pandas._libs.lib import item_from_zerodim
from pandas.errors import AbstractMethodError
from pandas.util._decorators import Appender
from pandas.core.dtypes.common import (
is_float,
is_integer,
is_iterator,
is_list_like,
is_numeric_dtype,
is_scalar,
is_sequence,
)
from pandas.core.dtypes.concat import concat_compat
from pandas.core.dtypes.generic import ABCDataFrame, ABCMultiIndex, ABCSeries
from pandas.core.dtypes.missing import _infer_fill_value, isna
import pandas.core.common as com
from pandas.core.indexers import (
check_array_indexer,
is_list_like_indexer,
length_of_indexer,
)
from pandas.core.indexes.api import Index
from pandas.core.indexes.base import InvalidIndexError
# "null slice"
_NS = slice(None, None)
# the public IndexSlicerMaker
class _IndexSlice:
"""
Create an object to more easily perform multi-index slicing.
See Also
--------
MultiIndex.remove_unused_levels : New MultiIndex with no unused levels.
Notes
-----
See :ref:`Defined Levels <advanced.shown_levels>`
for further info on slicing a MultiIndex.
Examples
--------
>>> midx = pd.MultiIndex.from_product([['A0','A1'], ['B0','B1','B2','B3']])
>>> columns = ['foo', 'bar']
>>> dfmi = pd.DataFrame(np.arange(16).reshape((len(midx), len(columns))),
index=midx, columns=columns)
Using the default slice command:
>>> dfmi.loc[(slice(None), slice('B0', 'B1')), :]
foo bar
A0 B0 0 1
B1 2 3
A1 B0 8 9
B1 10 11
Using the IndexSlice class for a more intuitive command:
>>> idx = pd.IndexSlice
>>> dfmi.loc[idx[:, 'B0':'B1'], :]
foo bar
A0 B0 0 1
B1 2 3
A1 B0 8 9
B1 10 11
"""
def __getitem__(self, arg):
return arg
IndexSlice = _IndexSlice()
class IndexingError(Exception):
pass
class IndexingMixin:
"""Mixin for adding .loc/.iloc/.at/.iat to Datafames and Series.
"""
@property
def iloc(self) -> "_iLocIndexer":
"""
Purely integer-location based indexing for selection by position.
``.iloc[]`` is primarily integer position based (from ``0`` to
``length-1`` of the axis), but may also be used with a boolean
array.
Allowed inputs are:
- An integer, e.g. ``5``.
- A list or array of integers, e.g. ``[4, 3, 0]``.
- A slice object with ints, e.g. ``1:7``.
- A boolean array.
- A ``callable`` function with one argument (the calling Series or
DataFrame) and that returns valid output for indexing (one of the above).
This is useful in method chains, when you don't have a reference to the
calling object, but would like to base your selection on some value.
``.iloc`` will raise ``IndexError`` if a requested indexer is
out-of-bounds, except *slice* indexers which allow out-of-bounds
indexing (this conforms with python/numpy *slice* semantics).
See more at :ref:`Selection by Position <indexing.integer>`.
See Also
--------
DataFrame.iat : Fast integer location scalar accessor.
DataFrame.loc : Purely label-location based indexer for selection by label.
Series.iloc : Purely integer-location based indexing for
selection by position.
Examples
--------
>>> mydict = [{'a': 1, 'b': 2, 'c': 3, 'd': 4},
... {'a': 100, 'b': 200, 'c': 300, 'd': 400},
... {'a': 1000, 'b': 2000, 'c': 3000, 'd': 4000 }]
>>> df = pd.DataFrame(mydict)
>>> df
a b c d
0 1 2 3 4
1 100 200 300 400
2 1000 2000 3000 4000
**Indexing just the rows**
With a scalar integer.
>>> type(df.iloc[0])
<class 'pandas.core.series.Series'>
>>> df.iloc[0]
a 1
b 2
c 3
d 4
Name: 0, dtype: int64
With a list of integers.
>>> df.iloc[[0]]
a b c d
0 1 2 3 4
>>> type(df.iloc[[0]])
<class 'pandas.core.frame.DataFrame'>
>>> df.iloc[[0, 1]]
a b c d
0 1 2 3 4
1 100 200 300 400
With a `slice` object.
>>> df.iloc[:3]
a b c d
0 1 2 3 4
1 100 200 300 400
2 1000 2000 3000 4000
With a boolean mask the same length as the index.
>>> df.iloc[[True, False, True]]
a b c d
0 1 2 3 4
2 1000 2000 3000 4000
With a callable, useful in method chains. The `x` passed
to the ``lambda`` is the DataFrame being sliced. This selects
the rows whose index label even.
>>> df.iloc[lambda x: x.index % 2 == 0]
a b c d
0 1 2 3 4
2 1000 2000 3000 4000
**Indexing both axes**
You can mix the indexer types for the index and columns. Use ``:`` to
select the entire axis.
With scalar integers.
>>> df.iloc[0, 1]
2
With lists of integers.
>>> df.iloc[[0, 2], [1, 3]]
b d
0 2 4
2 2000 4000
With `slice` objects.
>>> df.iloc[1:3, 0:3]
a b c
1 100 200 300
2 1000 2000 3000
With a boolean array whose length matches the columns.
>>> df.iloc[:, [True, False, True, False]]
a c
0 1 3
1 100 300
2 1000 3000
With a callable function that expects the Series or DataFrame.
>>> df.iloc[:, lambda df: [0, 2]]
a c
0 1 3
1 100 300
2 1000 3000
"""
return _iLocIndexer("iloc", self)
@property
def loc(self) -> "_LocIndexer":
"""
Access a group of rows and columns by label(s) or a boolean array.
``.loc[]`` is primarily label based, but may also be used with a
boolean array.
Allowed inputs are:
- A single label, e.g. ``5`` or ``'a'``, (note that ``5`` is
interpreted as a *label* of the index, and **never** as an
integer position along the index).
- A list or array of labels, e.g. ``['a', 'b', 'c']``.
- A slice object with labels, e.g. ``'a':'f'``.
.. warning:: Note that contrary to usual python slices, **both** the
start and the stop are included
- A boolean array of the same length as the axis being sliced,
e.g. ``[True, False, True]``.
- A ``callable`` function with one argument (the calling Series or
DataFrame) and that returns valid output for indexing (one of the above)
See more at :ref:`Selection by Label <indexing.label>`
Raises
------
KeyError
If any items are not found.
See Also
--------
DataFrame.at : Access a single value for a row/column label pair.
DataFrame.iloc : Access group of rows and columns by integer position(s).
DataFrame.xs : Returns a cross-section (row(s) or column(s)) from the
Series/DataFrame.
Series.loc : Access group of values using labels.
Examples
--------
**Getting values**
>>> df = pd.DataFrame([[1, 2], [4, 5], [7, 8]],
... index=['cobra', 'viper', 'sidewinder'],
... columns=['max_speed', 'shield'])
>>> df
max_speed shield
cobra 1 2
viper 4 5
sidewinder 7 8
Single label. Note this returns the row as a Series.
>>> df.loc['viper']
max_speed 4
shield 5
Name: viper, dtype: int64
List of labels. Note using ``[[]]`` returns a DataFrame.
>>> df.loc[['viper', 'sidewinder']]
max_speed shield
viper 4 5
sidewinder 7 8
Single label for row and column
>>> df.loc['cobra', 'shield']
2
Slice with labels for row and single label for column. As mentioned
above, note that both the start and stop of the slice are included.
>>> df.loc['cobra':'viper', 'max_speed']
cobra 1
viper 4
Name: max_speed, dtype: int64
Boolean list with the same length as the row axis
>>> df.loc[[False, False, True]]
max_speed shield
sidewinder 7 8
Conditional that returns a boolean Series
>>> df.loc[df['shield'] > 6]
max_speed shield
sidewinder 7 8
Conditional that returns a boolean Series with column labels specified
>>> df.loc[df['shield'] > 6, ['max_speed']]
max_speed
sidewinder 7
Callable that returns a boolean Series
>>> df.loc[lambda df: df['shield'] == 8]
max_speed shield
sidewinder 7 8
**Setting values**
Set value for all items matching the list of labels
>>> df.loc[['viper', 'sidewinder'], ['shield']] = 50
>>> df
max_speed shield
cobra 1 2
viper 4 50
sidewinder 7 50
Set value for an entire row
>>> df.loc['cobra'] = 10
>>> df
max_speed shield
cobra 10 10
viper 4 50
sidewinder 7 50
Set value for an entire column
>>> df.loc[:, 'max_speed'] = 30
>>> df
max_speed shield
cobra 30 10
viper 30 50
sidewinder 30 50
Set value for rows matching callable condition
>>> df.loc[df['shield'] > 35] = 0
>>> df
max_speed shield
cobra 30 10
viper 0 0
sidewinder 0 0
**Getting values on a DataFrame with an index that has integer labels**
Another example using integers for the index
>>> df = pd.DataFrame([[1, 2], [4, 5], [7, 8]],
... index=[7, 8, 9], columns=['max_speed', 'shield'])
>>> df
max_speed shield
7 1 2
8 4 5
9 7 8
Slice with integer labels for rows. As mentioned above, note that both
the start and stop of the slice are included.
>>> df.loc[7:9]
max_speed shield
7 1 2
8 4 5
9 7 8
**Getting values with a MultiIndex**
A number of examples using a DataFrame with a MultiIndex
>>> tuples = [
... ('cobra', 'mark i'), ('cobra', 'mark ii'),
... ('sidewinder', 'mark i'), ('sidewinder', 'mark ii'),
... ('viper', 'mark ii'), ('viper', 'mark iii')
... ]
>>> index = pd.MultiIndex.from_tuples(tuples)
>>> values = [[12, 2], [0, 4], [10, 20],
... [1, 4], [7, 1], [16, 36]]
>>> df = pd.DataFrame(values, columns=['max_speed', 'shield'], index=index)
>>> df
max_speed shield
cobra mark i 12 2
mark ii 0 4
sidewinder mark i 10 20
mark ii 1 4
viper mark ii 7 1
mark iii 16 36
Single label. Note this returns a DataFrame with a single index.
>>> df.loc['cobra']
max_speed shield
mark i 12 2
mark ii 0 4
Single index tuple. Note this returns a Series.
>>> df.loc[('cobra', 'mark ii')]
max_speed 0
shield 4
Name: (cobra, mark ii), dtype: int64
Single label for row and column. Similar to passing in a tuple, this
returns a Series.
>>> df.loc['cobra', 'mark i']
max_speed 12
shield 2
Name: (cobra, mark i), dtype: int64
Single tuple. Note using ``[[]]`` returns a DataFrame.
>>> df.loc[[('cobra', 'mark ii')]]
max_speed shield
cobra mark ii 0 4
Single tuple for the index with a single label for the column
>>> df.loc[('cobra', 'mark i'), 'shield']
2
Slice from index tuple to single label
>>> df.loc[('cobra', 'mark i'):'viper']
max_speed shield
cobra mark i 12 2
mark ii 0 4
sidewinder mark i 10 20
mark ii 1 4
viper mark ii 7 1
mark iii 16 36
Slice from index tuple to index tuple
>>> df.loc[('cobra', 'mark i'):('viper', 'mark ii')]
max_speed shield
cobra mark i 12 2
mark ii 0 4
sidewinder mark i 10 20
mark ii 1 4
viper mark ii 7 1
"""
return _LocIndexer("loc", self)
@property
def at(self) -> "_AtIndexer":
"""
Access a single value for a row/column label pair.
Similar to ``loc``, in that both provide label-based lookups. Use
``at`` if you only need to get or set a single value in a DataFrame
or Series.
Raises
------
KeyError
If 'label' does not exist in DataFrame.
See Also
--------
DataFrame.iat : Access a single value for a row/column pair by integer
position.
DataFrame.loc : Access a group of rows and columns by label(s).
Series.at : Access a single value using a label.
Examples
--------
>>> df = pd.DataFrame([[0, 2, 3], [0, 4, 1], [10, 20, 30]],
... index=[4, 5, 6], columns=['A', 'B', 'C'])
>>> df
A B C
4 0 2 3
5 0 4 1
6 10 20 30
Get value at specified row/column pair
>>> df.at[4, 'B']
2
Set value at specified row/column pair
>>> df.at[4, 'B'] = 10
>>> df.at[4, 'B']
10
Get value within a Series
>>> df.loc[5].at['B']
4
"""
return _AtIndexer("at", self)
@property
def iat(self) -> "_iAtIndexer":
"""
Access a single value for a row/column pair by integer position.
Similar to ``iloc``, in that both provide integer-based lookups. Use
``iat`` if you only need to get or set a single value in a DataFrame
or Series.
Raises
------
IndexError
When integer position is out of bounds.
See Also
--------
DataFrame.at : Access a single value for a row/column label pair.
DataFrame.loc : Access a group of rows and columns by label(s).
DataFrame.iloc : Access a group of rows and columns by integer position(s).
Examples
--------
>>> df = pd.DataFrame([[0, 2, 3], [0, 4, 1], [10, 20, 30]],
... columns=['A', 'B', 'C'])
>>> df
A B C
0 0 2 3
1 0 4 1
2 10 20 30
Get value at specified row/column pair
>>> df.iat[1, 2]
1
Set value at specified row/column pair
>>> df.iat[1, 2] = 10
>>> df.iat[1, 2]
10
Get value within a series
>>> df.loc[0].iat[1]
2
"""
return _iAtIndexer("iat", self)
class _NDFrameIndexer(_NDFrameIndexerBase):
_valid_types: str
axis = None
def __call__(self, axis=None):
# we need to return a copy of ourselves
new_self = type(self)(self.name, self.obj)
if axis is not None:
axis = self.obj._get_axis_number(axis)
new_self.axis = axis
return new_self
def _get_label(self, label, axis: int):
if self.ndim == 1:
# for perf reasons we want to try _xs first
# as its basically direct indexing
# but will fail when the index is not present
# see GH5667
return self.obj._xs(label, axis=axis)
elif isinstance(label, tuple) and isinstance(label[axis], slice):
raise IndexingError("no slices here, handle elsewhere")
return self.obj._xs(label, axis=axis)
def _get_loc(self, key: int, axis: int):
return self.obj._ixs(key, axis=axis)
def _slice(self, obj, axis: int, kind=None):
return self.obj._slice(obj, axis=axis, kind=kind)
def _get_setitem_indexer(self, key):
if self.axis is not None:
return self._convert_tuple(key)
ax = self.obj._get_axis(0)
if isinstance(ax, ABCMultiIndex) and self.name != "iloc":
try:
return ax.get_loc(key)
except (TypeError, KeyError, InvalidIndexError):
# TypeError e.g. passed a bool
pass
if isinstance(key, tuple):
try:
return self._convert_tuple(key)
except IndexingError:
pass
if isinstance(key, range):
return list(key)
try:
return self._convert_to_indexer(key, axis=0)
except TypeError as e:
# invalid indexer type vs 'other' indexing errors
if "cannot do" in str(e):
raise
raise IndexingError(key)
def __setitem__(self, key, value):
if isinstance(key, tuple):
key = tuple(com.apply_if_callable(x, self.obj) for x in key)
else:
key = com.apply_if_callable(key, self.obj)
indexer = self._get_setitem_indexer(key)
self._setitem_with_indexer(indexer, value)
def _validate_key(self, key, axis: int):
"""
Ensure that key is valid for current indexer.
Parameters
----------
key : scalar, slice or list-like
Key requested.
axis : int
Dimension on which the indexing is being made.
Raises
------
TypeError
If the key (or some element of it) has wrong type.
IndexError
If the key (or some element of it) is out of bounds.
KeyError
If the key was not found.
"""
raise AbstractMethodError(self)
def _has_valid_tuple(self, key: Tuple):
"""
Check the key for valid keys across my indexer.
"""
for i, k in enumerate(key):
if i >= self.ndim:
raise IndexingError("Too many indexers")
try:
self._validate_key(k, i)
except ValueError:
raise ValueError(
"Location based indexing can only have "
f"[{self._valid_types}] types"
)
def _is_nested_tuple_indexer(self, tup: Tuple) -> bool:
"""
Returns
-------
bool
"""
if any(isinstance(ax, ABCMultiIndex) for ax in self.obj.axes):
return any(is_nested_tuple(tup, ax) for ax in self.obj.axes)
return False
def _convert_tuple(self, key):
keyidx = []
if self.axis is not None:
axis = self.obj._get_axis_number(self.axis)
for i in range(self.ndim):
if i == axis:
keyidx.append(self._convert_to_indexer(key, axis=axis))
else:
keyidx.append(slice(None))
else:
for i, k in enumerate(key):
if i >= self.ndim:
raise IndexingError("Too many indexers")
idx = self._convert_to_indexer(k, axis=i)
keyidx.append(idx)
return tuple(keyidx)
def _convert_scalar_indexer(self, key, axis: int):
# if we are accessing via lowered dim, use the last dim
ax = self.obj._get_axis(min(axis, self.ndim - 1))
# a scalar
return ax._convert_scalar_indexer(key, kind=self.name)
def _convert_slice_indexer(self, key: slice, axis: int):
# if we are accessing via lowered dim, use the last dim
ax = self.obj._get_axis(min(axis, self.ndim - 1))
return ax._convert_slice_indexer(key, kind=self.name)
def _has_valid_setitem_indexer(self, indexer) -> bool:
return True
def _has_valid_positional_setitem_indexer(self, indexer) -> bool:
"""
Validate that a positional indexer cannot enlarge its target
will raise if needed, does not modify the indexer externally.
Returns
-------
bool
"""
if isinstance(indexer, dict):
raise IndexError(f"{self.name} cannot enlarge its target object")
else:
if not isinstance(indexer, tuple):
indexer = _tuplify(self.ndim, indexer)
for ax, i in zip(self.obj.axes, indexer):
if isinstance(i, slice):
# should check the stop slice?
pass
elif is_list_like_indexer(i):
# should check the elements?
pass
elif is_integer(i):
if i >= len(ax):
raise IndexError(
f"{self.name} cannot enlarge its target object"
)
elif isinstance(i, dict):
raise IndexError(f"{self.name} cannot enlarge its target object")
return True
def _setitem_with_indexer(self, indexer, value):
self._has_valid_setitem_indexer(indexer)
# also has the side effect of consolidating in-place
from pandas import Series
info_axis = self.obj._info_axis_number
# maybe partial set
take_split_path = self.obj._is_mixed_type
# if there is only one block/type, still have to take split path
# unless the block is one-dimensional or it can hold the value
if not take_split_path and self.obj._data.blocks:
(blk,) = self.obj._data.blocks
if 1 < blk.ndim: # in case of dict, keys are indices
val = list(value.values()) if isinstance(value, dict) else value
take_split_path = not blk._can_hold_element(val)
# if we have any multi-indexes that have non-trivial slices
# (not null slices) then we must take the split path, xref
# GH 10360, GH 27841
if isinstance(indexer, tuple) and len(indexer) == len(self.obj.axes):
for i, ax in zip(indexer, self.obj.axes):
if isinstance(ax, ABCMultiIndex) and not (
is_integer(i) or com.is_null_slice(i)
):
take_split_path = True
break
if isinstance(indexer, tuple):
nindexer = []
for i, idx in enumerate(indexer):
if isinstance(idx, dict):
# reindex the axis to the new value
# and set inplace
key, _ = convert_missing_indexer(idx)
# if this is the items axes, then take the main missing
# path first
# this correctly sets the dtype and avoids cache issues
# essentially this separates out the block that is needed
# to possibly be modified
if self.ndim > 1 and i == self.obj._info_axis_number:
# add the new item, and set the value
# must have all defined axes if we have a scalar
# or a list-like on the non-info axes if we have a
# list-like
len_non_info_axes = (
len(_ax) for _i, _ax in enumerate(self.obj.axes) if _i != i
)
if any(not l for l in len_non_info_axes):
if not is_list_like_indexer(value):
raise ValueError(
"cannot set a frame with no "
"defined index and a scalar"
)
self.obj[key] = value
return self.obj
# add a new item with the dtype setup
self.obj[key] = _infer_fill_value(value)
new_indexer = convert_from_missing_indexer_tuple(
indexer, self.obj.axes
)
self._setitem_with_indexer(new_indexer, value)
return self.obj
# reindex the axis
# make sure to clear the cache because we are
# just replacing the block manager here
# so the object is the same
index = self.obj._get_axis(i)
labels = index.insert(len(index), key)
self.obj._data = self.obj.reindex(labels, axis=i)._data
self.obj._maybe_update_cacher(clear=True)
self.obj._is_copy = None
nindexer.append(labels.get_loc(key))
else:
nindexer.append(idx)
indexer = tuple(nindexer)
else:
indexer, missing = convert_missing_indexer(indexer)
if missing:
return self._setitem_with_indexer_missing(indexer, value)
# set
item_labels = self.obj._get_axis(info_axis)
# align and set the values
if take_split_path:
# Above we only set take_split_path to True for 2D cases
assert self.ndim == 2
assert info_axis == 1
if not isinstance(indexer, tuple):
indexer = _tuplify(self.ndim, indexer)
if isinstance(value, ABCSeries):
value = self._align_series(indexer, value)
info_idx = indexer[info_axis]
if is_integer(info_idx):
info_idx = [info_idx]
labels = item_labels[info_idx]
# if we have a partial multiindex, then need to adjust the plane
# indexer here
if len(labels) == 1 and isinstance(
self.obj[labels[0]].axes[0], ABCMultiIndex
):
item = labels[0]
obj = self.obj[item]
index = obj.index
idx = indexer[:info_axis][0]
plane_indexer = tuple([idx]) + indexer[info_axis + 1 :]
lplane_indexer = length_of_indexer(plane_indexer[0], index)
# require that we are setting the right number of values that
# we are indexing
if (
is_list_like_indexer(value)
and np.iterable(value)
and lplane_indexer != len(value)
):
if len(obj[idx]) != len(value):
raise ValueError(
"cannot set using a multi-index "
"selection indexer with a different "
"length than the value"
)
# make sure we have an ndarray
value = getattr(value, "values", value).ravel()
# we can directly set the series here
# as we select a slice indexer on the mi
idx = index._convert_slice_indexer(idx)
obj._consolidate_inplace()
obj = obj.copy()
obj._data = obj._data.setitem(indexer=tuple([idx]), value=value)
self.obj[item] = obj
return
# non-mi
else:
plane_indexer = indexer[:info_axis] + indexer[info_axis + 1 :]
plane_axis = self.obj.axes[:info_axis][0]
lplane_indexer = length_of_indexer(plane_indexer[0], plane_axis)
def setter(item, v):
s = self.obj[item]
pi = plane_indexer[0] if lplane_indexer == 1 else plane_indexer
# perform the equivalent of a setitem on the info axis
# as we have a null slice or a slice with full bounds
# which means essentially reassign to the columns of a
# multi-dim object
# GH6149 (null slice), GH10408 (full bounds)
if isinstance(pi, tuple) and all(
com.is_null_slice(idx) or com.is_full_slice(idx, len(self.obj))
for idx in pi
):
s = v
else:
# set the item, possibly having a dtype change
s._consolidate_inplace()
s = s.copy()
s._data = s._data.setitem(indexer=pi, value=v)
s._maybe_update_cacher(clear=True)
# reset the sliced object if unique
self.obj[item] = s
# we need an iterable, with a ndim of at least 1
# eg. don't pass through np.array(0)
if is_list_like_indexer(value) and getattr(value, "ndim", 1) > 0:
# we have an equal len Frame
if isinstance(value, ABCDataFrame):
sub_indexer = list(indexer)
multiindex_indexer = isinstance(labels, ABCMultiIndex)
for item in labels:
if item in value:
sub_indexer[info_axis] = item
v = self._align_series(
tuple(sub_indexer), value[item], multiindex_indexer
)
else:
v = np.nan
setter(item, v)
# we have an equal len ndarray/convertible to our labels
# hasattr first, to avoid coercing to ndarray without reason.
# But we may be relying on the ndarray coercion to check ndim.
# Why not just convert to an ndarray earlier on if needed?
elif np.ndim(value) == 2:
# note that this coerces the dtype if we are mixed
# GH 7551
value = np.array(value, dtype=object)
if len(labels) != value.shape[1]:
raise ValueError(
"Must have equal len keys and value "
"when setting with an ndarray"
)
for i, item in enumerate(labels):
# setting with a list, recoerces
setter(item, value[:, i].tolist())
# we have an equal len list/ndarray
elif _can_do_equal_len(
labels, value, plane_indexer, lplane_indexer, self.obj
):
setter(labels[0], value)
# per label values
else:
if len(labels) != len(value):
raise ValueError(
"Must have equal len keys and value "
"when setting with an iterable"
)
for item, v in zip(labels, value):
setter(item, v)
else:
# scalar
for item in labels:
setter(item, value)
else:
if isinstance(indexer, tuple):
indexer = maybe_convert_ix(*indexer)
# if we are setting on the info axis ONLY
# set using those methods to avoid block-splitting
# logic here
if (
len(indexer) > info_axis
and is_integer(indexer[info_axis])
and all(
com.is_null_slice(idx)
for i, idx in enumerate(indexer)
if i != info_axis
)
and item_labels.is_unique
):
self.obj[item_labels[indexer[info_axis]]] = value
return
if isinstance(value, (ABCSeries, dict)):
# TODO(EA): ExtensionBlock.setitem this causes issues with
# setting for extensionarrays that store dicts. Need to decide
# if it's worth supporting that.
value = self._align_series(indexer, Series(value))
elif isinstance(value, ABCDataFrame):
value = self._align_frame(indexer, value)
# check for chained assignment
self.obj._check_is_chained_assignment_possible()
# actually do the set
self.obj._consolidate_inplace()
self.obj._data = self.obj._data.setitem(indexer=indexer, value=value)
self.obj._maybe_update_cacher(clear=True)
def _setitem_with_indexer_missing(self, indexer, value):
"""
Insert new row(s) or column(s) into the Series or DataFrame.
"""
from pandas import Series
# reindex the axis to the new value
# and set inplace
if self.ndim == 1:
index = self.obj.index
new_index = index.insert(len(index), indexer)
# we have a coerced indexer, e.g. a float
# that matches in an Int64Index, so
# we will not create a duplicate index, rather
# index to that element
# e.g. 0.0 -> 0
# GH#12246
if index.is_unique:
new_indexer = index.get_indexer([new_index[-1]])
if (new_indexer != -1).any():
return self._setitem_with_indexer(new_indexer, value)
# this preserves dtype of the value
new_values = Series([value])._values
if len(self.obj._values):
# GH#22717 handle casting compatibility that np.concatenate
# does incorrectly
new_values = concat_compat([self.obj._values, new_values])
self.obj._data = self.obj._constructor(
new_values, index=new_index, name=self.obj.name
)._data
self.obj._maybe_update_cacher(clear=True)
return self.obj
elif self.ndim == 2:
if not len(self.obj.columns):
# no columns and scalar
raise ValueError("cannot set a frame with no defined columns")
if isinstance(value, ABCSeries):
# append a Series
value = value.reindex(index=self.obj.columns, copy=True)
value.name = indexer
else:
# a list-list
if is_list_like_indexer(value):
# must have conforming columns
if len(value) != len(self.obj.columns):
raise ValueError("cannot set a row with mismatched columns")
value = Series(value, index=self.obj.columns, name=indexer)
self.obj._data = self.obj.append(value)._data
self.obj._maybe_update_cacher(clear=True)
return self.obj
def _align_series(self, indexer, ser: ABCSeries, multiindex_indexer: bool = False):
"""
Parameters
----------
indexer : tuple, slice, scalar
Indexer used to get the locations that will be set to `ser`.
ser : pd.Series
Values to assign to the locations specified by `indexer`.
multiindex_indexer : boolean, optional
Defaults to False. Should be set to True if `indexer` was from
a `pd.MultiIndex`, to avoid unnecessary broadcasting.
Returns
-------
`np.array` of `ser` broadcast to the appropriate shape for assignment
to the locations selected by `indexer`
"""
if isinstance(indexer, (slice, np.ndarray, list, Index)):
indexer = tuple([indexer])
if isinstance(indexer, tuple):
# flatten np.ndarray indexers
def ravel(i):
return i.ravel() if isinstance(i, np.ndarray) else i
indexer = tuple(map(ravel, indexer))
aligners = [not com.is_null_slice(idx) for idx in indexer]
sum_aligners = sum(aligners)
single_aligner = sum_aligners == 1
is_frame = self.ndim == 2
obj = self.obj
# are we a single alignable value on a non-primary
# dim (e.g. panel: 1,2, or frame: 0) ?
# hence need to align to a single axis dimension
# rather that find all valid dims
# frame
if is_frame:
single_aligner = single_aligner and aligners[0]
# we have a frame, with multiple indexers on both axes; and a
# series, so need to broadcast (see GH5206)
if sum_aligners == self.ndim and all(is_sequence(_) for _ in indexer):
ser = ser.reindex(obj.axes[0][indexer[0]], copy=True)._values
# single indexer
if len(indexer) > 1 and not multiindex_indexer:
len_indexer = len(indexer[1])
ser = np.tile(ser, len_indexer).reshape(len_indexer, -1).T
return ser
for i, idx in enumerate(indexer):
ax = obj.axes[i]
# multiple aligners (or null slices)
if is_sequence(idx) or isinstance(idx, slice):
if single_aligner and com.is_null_slice(idx):
continue
new_ix = ax[idx]
if not is_list_like_indexer(new_ix):
new_ix = Index([new_ix])
else:
new_ix = Index(new_ix)
if ser.index.equals(new_ix) or not len(new_ix):
return ser._values.copy()
return ser.reindex(new_ix)._values
# 2 dims
elif single_aligner:
# reindex along index
ax = self.obj.axes[1]
if ser.index.equals(ax) or not len(ax):
return ser._values.copy()
return ser.reindex(ax)._values
elif is_scalar(indexer):
ax = self.obj._get_axis(1)
if ser.index.equals(ax):
return ser._values.copy()
return ser.reindex(ax)._values
raise ValueError("Incompatible indexer with Series")
def _align_frame(self, indexer, df: ABCDataFrame):
is_frame = self.ndim == 2
if isinstance(indexer, tuple):
idx, cols = None, None
sindexers = []
for i, ix in enumerate(indexer):
ax = self.obj.axes[i]
if is_sequence(ix) or isinstance(ix, slice):
if isinstance(ix, np.ndarray):
ix = ix.ravel()
if idx is None:
idx = ax[ix]
elif cols is None:
cols = ax[ix]
else:
break
else:
sindexers.append(i)
if idx is not None and cols is not None:
if df.index.equals(idx) and df.columns.equals(cols):
val = df.copy()._values
else:
val = df.reindex(idx, columns=cols)._values
return val
elif (isinstance(indexer, slice) or is_list_like_indexer(indexer)) and is_frame:
ax = self.obj.index[indexer]
if df.index.equals(ax):
val = df.copy()._values
else:
# we have a multi-index and are trying to align
# with a particular, level GH3738
if (
isinstance(ax, ABCMultiIndex)
and isinstance(df.index, ABCMultiIndex)
and ax.nlevels != df.index.nlevels
):
raise TypeError(
"cannot align on a multi-index with out "
"specifying the join levels"
)
val = df.reindex(index=ax)._values
return val
raise ValueError("Incompatible indexer with DataFrame")
def _getitem_tuple(self, tup: Tuple):
try:
return self._getitem_lowerdim(tup)
except IndexingError:
pass
# no multi-index, so validate all of the indexers
self._has_valid_tuple(tup)
# ugly hack for GH #836
if self._multi_take_opportunity(tup):
return self._multi_take(tup)
# no shortcut needed
retval = self.obj
for i, key in enumerate(tup):
if com.is_null_slice(key):
continue
retval = getattr(retval, self.name)._getitem_axis(key, axis=i)
return retval
def _multi_take_opportunity(self, tup: Tuple) -> bool:
"""
Check whether there is the possibility to use ``_multi_take``.
Currently the limit is that all axes being indexed, must be indexed with
list-likes.
Parameters
----------
tup : tuple
Tuple of indexers, one per axis.
Returns
-------
bool
Whether the current indexing,
can be passed through `_multi_take`.
"""
if not all(is_list_like_indexer(x) for x in tup):
return False
# just too complicated
if any(com.is_bool_indexer(x) for x in tup):
return False
return True
def _multi_take(self, tup: Tuple):
"""
Create the indexers for the passed tuple of keys, and
executes the take operation. This allows the take operation to be
executed all at once, rather than once for each dimension.
Improving efficiency.
Parameters
----------
tup : tuple
Tuple of indexers, one per axis.
Returns
-------
values: same type as the object being indexed
"""
# GH 836
o = self.obj
d = {
axis: self._get_listlike_indexer(key, axis)
for (key, axis) in zip(tup, o._AXIS_ORDERS)
}
return o._reindex_with_indexers(d, copy=True, allow_dups=True)
def _handle_lowerdim_multi_index_axis0(self, tup: Tuple):
# we have an axis0 multi-index, handle or raise
axis = self.axis or 0
try:
# fast path for series or for tup devoid of slices
return self._get_label(tup, axis=axis)
except TypeError:
# slices are unhashable
pass
except KeyError as ek:
# raise KeyError if number of indexers match
# else IndexingError will be raised
if len(tup) <= self.obj.index.nlevels and len(tup) > self.ndim:
raise ek
return None
def _getitem_lowerdim(self, tup: Tuple):
# we can directly get the axis result since the axis is specified
if self.axis is not None:
axis = self.obj._get_axis_number(self.axis)
return self._getitem_axis(tup, axis=axis)
# we may have a nested tuples indexer here
if self._is_nested_tuple_indexer(tup):
return self._getitem_nested_tuple(tup)
# we maybe be using a tuple to represent multiple dimensions here
ax0 = self.obj._get_axis(0)
# ...but iloc should handle the tuple as simple integer-location
# instead of checking it as multiindex representation (GH 13797)
if isinstance(ax0, ABCMultiIndex) and self.name != "iloc":
result = self._handle_lowerdim_multi_index_axis0(tup)
if result is not None:
return result
if len(tup) > self.ndim:
raise IndexingError("Too many indexers. handle elsewhere")
for i, key in enumerate(tup):
if is_label_like(key) or isinstance(key, tuple):
section = self._getitem_axis(key, axis=i)
# we have yielded a scalar ?
if not is_list_like_indexer(section):
return section
elif section.ndim == self.ndim:
# we're in the middle of slicing through a MultiIndex
# revise the key wrt to `section` by inserting an _NS
new_key = tup[:i] + (_NS,) + tup[i + 1 :]
else:
new_key = tup[:i] + tup[i + 1 :]
# unfortunately need an odious kludge here because of
# DataFrame transposing convention
if (
isinstance(section, ABCDataFrame)
and i > 0
and len(new_key) == 2
):
a, b = new_key
new_key = b, a
if len(new_key) == 1:
new_key = new_key[0]
# Slices should return views, but calling iloc/loc with a null
# slice returns a new object.
if com.is_null_slice(new_key):
return section
# This is an elided recursive call to iloc/loc/etc'
return getattr(section, self.name)[new_key]
raise IndexingError("not applicable")
def _getitem_nested_tuple(self, tup: Tuple):
# we have a nested tuple so have at least 1 multi-index level
# we should be able to match up the dimensionality here
# we have too many indexers for our dim, but have at least 1
# multi-index dimension, try to see if we have something like
# a tuple passed to a series with a multi-index
if len(tup) > self.ndim:
result = self._handle_lowerdim_multi_index_axis0(tup)
if result is not None:
return result
# this is a series with a multi-index specified a tuple of
# selectors
axis = self.axis or 0
return self._getitem_axis(tup, axis=axis)
# handle the multi-axis by taking sections and reducing
# this is iterative
obj = self.obj
axis = 0
for i, key in enumerate(tup):
if com.is_null_slice(key):
axis += 1
continue
current_ndim = obj.ndim
obj = getattr(obj, self.name)._getitem_axis(key, axis=axis)
axis += 1
# if we have a scalar, we are done
if is_scalar(obj) or not hasattr(obj, "ndim"):
break
# has the dim of the obj changed?
# GH 7199
if obj.ndim < current_ndim:
axis -= 1
return obj
def _get_listlike_indexer(self, key, axis: int, raise_missing: bool = False):
"""
Transform a list-like of keys into a new index and an indexer.
Parameters
----------
key : list-like
Targeted labels.
axis: int
Dimension on which the indexing is being made.
raise_missing: bool, default False
Whether to raise a KeyError if some labels were not found.
Will be removed in the future, and then this method will always behave as
if ``raise_missing=True``.
Raises
------
KeyError
If at least one key was requested but none was found, and
raise_missing=True.
Returns
-------
keyarr: Index
New index (coinciding with 'key' if the axis is unique).
values : array-like
Indexer for the return object, -1 denotes keys not found.
"""
o = self.obj
ax = o._get_axis(axis)
# Have the index compute an indexer or return None
# if it cannot handle:
indexer, keyarr = ax._convert_listlike_indexer(key, kind=self.name)
# We only act on all found values:
if indexer is not None and (indexer != -1).all():
self._validate_read_indexer(key, indexer, axis, raise_missing=raise_missing)
return ax[indexer], indexer
if ax.is_unique and not getattr(ax, "is_overlapping", False):
indexer = ax.get_indexer_for(key)
keyarr = ax.reindex(keyarr)[0]
else:
keyarr, indexer, new_indexer = ax._reindex_non_unique(keyarr)
self._validate_read_indexer(keyarr, indexer, axis, raise_missing=raise_missing)
return keyarr, indexer
def _getitem_iterable(self, key, axis: int):
"""
Index current object with an an iterable key.
The iterable key can be a boolean indexer or a collection of keys.
Parameters
----------
key : iterable
Targeted labels or boolean indexer.
axis: int
Dimension on which the indexing is being made.
Raises
------
KeyError
If no key was found. Will change in the future to raise if not all
keys were found.
IndexingError
If the boolean indexer is unalignable with the object being
indexed.
Returns
-------
scalar, DataFrame, or Series: indexed value(s).
"""
# caller is responsible for ensuring non-None axis
self._validate_key(key, axis)
labels = self.obj._get_axis(axis)
if com.is_bool_indexer(key):
# A boolean indexer
key = check_bool_indexer(labels, key)
(inds,) = key.nonzero()
return self.obj._take_with_is_copy(inds, axis=axis)
else:
# A collection of keys
keyarr, indexer = self._get_listlike_indexer(key, axis, raise_missing=False)
return self.obj._reindex_with_indexers(
{axis: [keyarr, indexer]}, copy=True, allow_dups=True
)
def _validate_read_indexer(
self, key, indexer, axis: int, raise_missing: bool = False
):
"""
Check that indexer can be used to return a result.
e.g. at least one element was found,
unless the list of keys was actually empty.
Parameters
----------
key : list-like
Targeted labels (only used to show correct error message).
indexer: array-like of booleans
Indices corresponding to the key,
(with -1 indicating not found).
axis: int
Dimension on which the indexing is being made.
raise_missing: bool
Whether to raise a KeyError if some labels are not found. Will be
removed in the future, and then this method will always behave as
if raise_missing=True.
Raises
------
KeyError
If at least one key was requested but none was found, and
raise_missing=True.
"""
ax = self.obj._get_axis(axis)
if len(key) == 0:
return
# Count missing values:
missing = (indexer < 0).sum()
if missing:
if missing == len(indexer):
axis_name = self.obj._get_axis_name(axis)
raise KeyError(f"None of [{key}] are in the [{axis_name}]")
# We (temporarily) allow for some missing keys with .loc, except in
# some cases (e.g. setting) in which "raise_missing" will be False
if not (self.name == "loc" and not raise_missing):
not_found = list(set(key) - set(ax))
raise KeyError(f"{not_found} not in index")
# we skip the warning on Categorical/Interval
# as this check is actually done (check for
# non-missing values), but a bit later in the
# code, so we want to avoid warning & then
# just raising
if not (ax.is_categorical() or ax.is_interval()):
raise KeyError(
"Passing list-likes to .loc or [] with any missing labels "
"is no longer supported, see "
"https://pandas.pydata.org/pandas-docs/stable/user_guide/indexing.html#deprecate-loc-reindex-listlike" # noqa:E501
)
def _convert_to_indexer(self, key, axis: int):
"""
Convert indexing key into something we can use to do actual fancy
indexing on a ndarray.
Examples
ix[:5] -> slice(0, 5)
ix[[1,2,3]] -> [1,2,3]
ix[['foo', 'bar', 'baz']] -> [i, j, k] (indices of foo, bar, baz)
Going by Zen of Python?
'In the face of ambiguity, refuse the temptation to guess.'
raise AmbiguousIndexError with integer labels?
- No, prefer label-based indexing
"""
labels = self.obj._get_axis(axis)
if isinstance(key, slice):
return self._convert_slice_indexer(key, axis)
# try to find out correct indexer, if not type correct raise
try:
key = self._convert_scalar_indexer(key, axis)
except TypeError:
# but we will allow setting
pass
# see if we are positional in nature
is_int_index = labels.is_integer()
is_int_positional = is_integer(key) and not is_int_index
if is_scalar(key) or isinstance(labels, ABCMultiIndex):
# Otherwise get_loc will raise InvalidIndexError
# if we are a label return me
try:
return labels.get_loc(key)
except LookupError:
if isinstance(key, tuple) and isinstance(labels, ABCMultiIndex):
if len(key) == labels.nlevels:
return {"key": key}
raise
except TypeError:
pass
except ValueError:
if not is_int_positional:
raise
# a positional
if is_int_positional:
# if we are setting and its not a valid location
# its an insert which fails by definition
if self.name == "loc":
# always valid
return {"key": key}
if key >= self.obj.shape[axis] and not isinstance(labels, ABCMultiIndex):
# a positional
raise ValueError("cannot set by positional indexing with enlargement")
return key
if is_nested_tuple(key, labels):
return labels.get_locs(key)
elif is_list_like_indexer(key):
if com.is_bool_indexer(key):
key = check_bool_indexer(labels, key)
(inds,) = key.nonzero()
return inds
else:
# When setting, missing keys are not allowed, even with .loc:
return self._get_listlike_indexer(key, axis, raise_missing=True)[1]
else:
try:
return labels.get_loc(key)
except LookupError:
# allow a not found key only if we are a setter
if not is_list_like_indexer(key):
return {"key": key}
raise
class _LocationIndexer(_NDFrameIndexer):
_takeable: bool = False
def __getitem__(self, key):
if type(key) is tuple:
key = tuple(com.apply_if_callable(x, self.obj) for x in key)
if self._is_scalar_access(key):
try:
return self.obj._get_value(*key, takeable=self._takeable)
except (KeyError, IndexError, AttributeError):
# AttributeError for IntervalTree get_value
pass
return self._getitem_tuple(key)
else:
# we by definition only have the 0th axis
axis = self.axis or 0
maybe_callable = com.apply_if_callable(key, self.obj)
return self._getitem_axis(maybe_callable, axis=axis)
def _is_scalar_access(self, key: Tuple):
raise NotImplementedError()
def _getitem_axis(self, key, axis: int):
raise NotImplementedError()
def _getbool_axis(self, key, axis: int):
# caller is responsible for ensuring non-None axis
labels = self.obj._get_axis(axis)
key = check_bool_indexer(labels, key)
inds = key.nonzero()[0]
return self.obj._take_with_is_copy(inds, axis=axis)
@Appender(IndexingMixin.loc.__doc__)
class _LocIndexer(_LocationIndexer):
_valid_types = (
"labels (MUST BE IN THE INDEX), slices of labels (BOTH "
"endpoints included! Can be slices of integers if the "
"index is integers), listlike of labels, boolean"
)
@Appender(_NDFrameIndexer._validate_key.__doc__)
def _validate_key(self, key, axis: int):
# valid for a collection of labels (we check their presence later)
# slice of labels (where start-end in labels)
# slice of integers (only if in the labels)
# boolean
if isinstance(key, slice):
return
if com.is_bool_indexer(key):
return
if not is_list_like_indexer(key):
self._convert_scalar_indexer(key, axis)
def _is_scalar_access(self, key: Tuple) -> bool:
"""
Returns
-------
bool
"""
# this is a shortcut accessor to both .loc and .iloc
# that provide the equivalent access of .at and .iat
# a) avoid getting things via sections and (to minimize dtype changes)
# b) provide a performant path
if len(key) != self.ndim:
return False
for i, k in enumerate(key):
if not is_scalar(k):
return False
ax = self.obj.axes[i]
if isinstance(ax, ABCMultiIndex):
return False
if isinstance(k, str) and ax._supports_partial_string_indexing:
# partial string indexing, df.loc['2000', 'A']
# should not be considered scalar
return False
if not ax.is_unique:
return False
return True
def _get_partial_string_timestamp_match_key(self, key, labels):
"""
Translate any partial string timestamp matches in key, returning the
new key.
(GH 10331)
"""
if isinstance(labels, ABCMultiIndex):
if (
isinstance(key, str)
and labels.levels[0]._supports_partial_string_indexing
):
# Convert key '2016-01-01' to
# ('2016-01-01'[, slice(None, None, None)]+)
key = tuple([key] + [slice(None)] * (len(labels.levels) - 1))
if isinstance(key, tuple):
# Convert (..., '2016-01-01', ...) in tuple to
# (..., slice('2016-01-01', '2016-01-01', None), ...)
new_key = []
for i, component in enumerate(key):
if (
isinstance(component, str)
and labels.levels[i]._supports_partial_string_indexing
):
new_key.append(slice(component, component, None))
else:
new_key.append(component)
key = tuple(new_key)
return key
def _getitem_axis(self, key, axis: int):
key = item_from_zerodim(key)
if is_iterator(key):
key = list(key)
labels = self.obj._get_axis(axis)
key = self._get_partial_string_timestamp_match_key(key, labels)
if isinstance(key, slice):
self._validate_key(key, axis)
return self._get_slice_axis(key, axis=axis)
elif com.is_bool_indexer(key):
return self._getbool_axis(key, axis=axis)
elif is_list_like_indexer(key):
# convert various list-like indexers
# to a list of keys
# we will use the *values* of the object
# and NOT the index if its a PandasObject
if isinstance(labels, ABCMultiIndex):
if isinstance(key, (ABCSeries, np.ndarray)) and key.ndim <= 1:
# Series, or 0,1 ndim ndarray
# GH 14730
key = list(key)
elif isinstance(key, ABCDataFrame):
# GH 15438
raise NotImplementedError(
"Indexing a MultiIndex with a "
"DataFrame key is not "
"implemented"
)
elif hasattr(key, "ndim") and key.ndim > 1:
raise NotImplementedError(
"Indexing a MultiIndex with a "
"multidimensional key is not "
"implemented"
)
if (
not isinstance(key, tuple)
and len(key)
and not isinstance(key[0], tuple)
):
key = tuple([key])
# an iterable multi-selection
if not (isinstance(key, tuple) and isinstance(labels, ABCMultiIndex)):
if hasattr(key, "ndim") and key.ndim > 1:
raise ValueError("Cannot index with multidimensional key")
return self._getitem_iterable(key, axis=axis)
# nested tuple slicing
if is_nested_tuple(key, labels):
locs = labels.get_locs(key)
indexer = [slice(None)] * self.ndim
indexer[axis] = locs
return self.obj.iloc[tuple(indexer)]
# fall thru to straight lookup
self._validate_key(key, axis)
return self._get_label(key, axis=axis)
def _get_slice_axis(self, slice_obj: slice, axis: int):
"""
This is pretty simple as we just have to deal with labels.
"""
# caller is responsible for ensuring non-None axis
obj = self.obj
if not need_slice(slice_obj):
return obj.copy(deep=False)
labels = obj._get_axis(axis)
indexer = labels.slice_indexer(
slice_obj.start, slice_obj.stop, slice_obj.step, kind=self.name
)
if isinstance(indexer, slice):
return self._slice(indexer, axis=axis, kind="iloc")
else:
# DatetimeIndex overrides Index.slice_indexer and may
# return a DatetimeIndex instead of a slice object.
return self.obj.take(indexer, axis=axis)
@Appender(IndexingMixin.iloc.__doc__)
class _iLocIndexer(_LocationIndexer):
_valid_types = (
"integer, integer slice (START point is INCLUDED, END "
"point is EXCLUDED), listlike of integers, boolean array"
)
_takeable = True
def _validate_key(self, key, axis: int):
if com.is_bool_indexer(key):
if hasattr(key, "index") and isinstance(key.index, Index):
if key.index.inferred_type == "integer":
raise NotImplementedError(
"iLocation based boolean "
"indexing on an integer type "
"is not available"
)
raise ValueError(
"iLocation based boolean indexing cannot use "
"an indexable as a mask"
)
return
if isinstance(key, slice):
return
elif is_integer(key):
self._validate_integer(key, axis)
elif isinstance(key, tuple):
# a tuple should already have been caught by this point
# so don't treat a tuple as a valid indexer
raise IndexingError("Too many indexers")
elif is_list_like_indexer(key):
arr = np.array(key)
len_axis = len(self.obj._get_axis(axis))
# check that the key has a numeric dtype
if not is_numeric_dtype(arr.dtype):
raise IndexError(f".iloc requires numeric indexers, got {arr}")
# check that the key does not exceed the maximum size of the index
if len(arr) and (arr.max() >= len_axis or arr.min() < -len_axis):
raise IndexError("positional indexers are out-of-bounds")
else:
raise ValueError(f"Can only index by location with a [{self._valid_types}]")
def _has_valid_setitem_indexer(self, indexer):
self._has_valid_positional_setitem_indexer(indexer)
def _is_scalar_access(self, key: Tuple) -> bool:
"""
Returns
-------
bool
"""
# this is a shortcut accessor to both .loc and .iloc
# that provide the equivalent access of .at and .iat
# a) avoid getting things via sections and (to minimize dtype changes)
# b) provide a performant path
if len(key) != self.ndim:
return False
for i, k in enumerate(key):
if not is_integer(k):
return False
ax = self.obj.axes[i]
if not ax.is_unique:
return False
return True
def _validate_integer(self, key: int, axis: int) -> None:
"""
Check that 'key' is a valid position in the desired axis.
Parameters
----------
key : int
Requested position.
axis : int
Desired axis.
Raises
------
IndexError
If 'key' is not a valid position in axis 'axis'.
"""
len_axis = len(self.obj._get_axis(axis))
if key >= len_axis or key < -len_axis:
raise IndexError("single positional indexer is out-of-bounds")
def _getitem_tuple(self, tup: Tuple):
self._has_valid_tuple(tup)
try:
return self._getitem_lowerdim(tup)
except IndexingError:
pass
retval = self.obj
axis = 0
for i, key in enumerate(tup):
if com.is_null_slice(key):
axis += 1
continue
retval = getattr(retval, self.name)._getitem_axis(key, axis=axis)
# if the dim was reduced, then pass a lower-dim the next time
if retval.ndim < self.ndim:
# TODO: this is never reached in tests; can we confirm that
# it is impossible?
axis -= 1
# try to get for the next axis
axis += 1
return retval
def _get_list_axis(self, key, axis: int):
"""
Return Series values by list or array of integers.
Parameters
----------
key : list-like positional indexer
axis : int
Returns
-------
Series object
Notes
-----
`axis` can only be zero.
"""
try:
return self.obj._take_with_is_copy(key, axis=axis)
except IndexError:
# re-raise with different error message
raise IndexError("positional indexers are out-of-bounds")
def _getitem_axis(self, key, axis: int):
if isinstance(key, slice):
return self._get_slice_axis(key, axis=axis)
if isinstance(key, list):
key = np.asarray(key)
if com.is_bool_indexer(key):
self._validate_key(key, axis)
return self._getbool_axis(key, axis=axis)
# a list of integers
elif is_list_like_indexer(key):
return self._get_list_axis(key, axis=axis)
# a single integer
else:
key = item_from_zerodim(key)
if not is_integer(key):
raise TypeError("Cannot index by location index with a non-integer key")
# validate the location
self._validate_integer(key, axis)
return self._get_loc(key, axis=axis)
def _get_slice_axis(self, slice_obj: slice, axis: int):
# caller is responsible for ensuring non-None axis
obj = self.obj
if not need_slice(slice_obj):
return obj.copy(deep=False)
indexer = self._convert_slice_indexer(slice_obj, axis)
return self._slice(indexer, axis=axis, kind="iloc")
def _convert_to_indexer(self, key, axis: int):
"""
Much simpler as we only have to deal with our valid types.
"""
# make need to convert a float key
if isinstance(key, slice):
return self._convert_slice_indexer(key, axis)
elif is_float(key):
return self._convert_scalar_indexer(key, axis)
try:
self._validate_key(key, axis)
return key
except ValueError:
raise ValueError(f"Can only index by location with a [{self._valid_types}]")
class _ScalarAccessIndexer(_NDFrameIndexerBase):
"""
Access scalars quickly.
"""
def _convert_key(self, key, is_setter: bool = False):
raise AbstractMethodError(self)
def __getitem__(self, key):
if not isinstance(key, tuple):
# we could have a convertible item here (e.g. Timestamp)
if not is_list_like_indexer(key):
key = tuple([key])
else:
raise ValueError("Invalid call for scalar access (getting)!")
key = self._convert_key(key)
return self.obj._get_value(*key, takeable=self._takeable)
def __setitem__(self, key, value):
if isinstance(key, tuple):
key = tuple(com.apply_if_callable(x, self.obj) for x in key)
else:
# scalar callable may return tuple
key = com.apply_if_callable(key, self.obj)
if not isinstance(key, tuple):
key = _tuplify(self.ndim, key)
if len(key) != self.ndim:
raise ValueError("Not enough indexers for scalar access (setting)!")
key = list(self._convert_key(key, is_setter=True))
self.obj._set_value(*key, value=value, takeable=self._takeable)
@Appender(IndexingMixin.at.__doc__)
class _AtIndexer(_ScalarAccessIndexer):
_takeable = False
def _convert_key(self, key, is_setter: bool = False):
"""
Require they keys to be the same type as the index. (so we don't
fallback)
"""
# allow arbitrary setting
if is_setter:
return list(key)
for ax, i in zip(self.obj.axes, key):
if ax.is_integer():
if not is_integer(i):
raise ValueError(
"At based indexing on an integer index "
"can only have integer indexers"
)
else:
if is_integer(i) and not ax.holds_integer():
raise ValueError(
"At based indexing on an non-integer "
"index can only have non-integer "
"indexers"
)
return key
@Appender(IndexingMixin.iat.__doc__)
class _iAtIndexer(_ScalarAccessIndexer):
_takeable = True
def _convert_key(self, key, is_setter: bool = False):
"""
Require integer args. (and convert to label arguments)
"""
for a, i in zip(self.obj.axes, key):
if not is_integer(i):
raise ValueError("iAt based indexing can only have integer indexers")
return key
def _tuplify(ndim: int, loc: Hashable) -> Tuple[Union[Hashable, slice], ...]:
"""
Given an indexer for the first dimension, create an equivalent tuple
for indexing over all dimensions.
Parameters
----------
ndim : int
loc : object
Returns
-------
tuple
"""
_tup: List[Union[Hashable, slice]]
_tup = [slice(None, None) for _ in range(ndim)]
_tup[0] = loc
return tuple(_tup)
def convert_to_index_sliceable(obj, key):
"""
If we are index sliceable, then return my slicer, otherwise return None.
"""
idx = obj.index
if isinstance(key, slice):
return idx._convert_slice_indexer(key, kind="getitem")
elif isinstance(key, str):
# we are an actual column
if key in obj._data.items:
return None
# We might have a datetimelike string that we can translate to a
# slice here via partial string indexing
if idx._supports_partial_string_indexing:
try:
return idx._get_string_slice(key)
except (KeyError, ValueError, NotImplementedError):
return None
return None
def check_bool_indexer(index: Index, key) -> np.ndarray:
"""
Check if key is a valid boolean indexer for an object with such index and
perform reindexing or conversion if needed.
This function assumes that is_bool_indexer(key) == True.
Parameters
----------
index : Index
Index of the object on which the indexing is done.
key : list-like
Boolean indexer to check.
Returns
-------
np.array
Resulting key.
Raises
------
IndexError
If the key does not have the same length as index.
IndexingError
If the index of the key is unalignable to index.
"""
result = key
if isinstance(key, ABCSeries) and not key.index.equals(index):
result = result.reindex(index)
mask = isna(result._values)
if mask.any():
raise IndexingError(
"Unalignable boolean Series provided as "
"indexer (index of the boolean Series and of "
"the indexed object do not match)."
)
result = result.astype(bool)._values
else:
# key might be sparse / object-dtype bool, check_array_indexer needs bool array
result = np.asarray(result, dtype=bool)
result = check_array_indexer(index, result)
return result
def convert_missing_indexer(indexer):
"""
Reverse convert a missing indexer, which is a dict
return the scalar indexer and a boolean indicating if we converted
"""
if isinstance(indexer, dict):
# a missing key (but not a tuple indexer)
indexer = indexer["key"]
if isinstance(indexer, bool):
raise KeyError("cannot use a single bool to index into setitem")
return indexer, True
return indexer, False
def convert_from_missing_indexer_tuple(indexer, axes):
"""
Create a filtered indexer that doesn't have any missing indexers.
"""
def get_indexer(_i, _idx):
return axes[_i].get_loc(_idx["key"]) if isinstance(_idx, dict) else _idx
return tuple(get_indexer(_i, _idx) for _i, _idx in enumerate(indexer))
def maybe_convert_ix(*args):
"""
We likely want to take the cross-product.
"""
ixify = True
for arg in args:
if not isinstance(arg, (np.ndarray, list, ABCSeries, Index)):
ixify = False
if ixify:
return np.ix_(*args)
else:
return args
def is_nested_tuple(tup, labels) -> bool:
"""
Returns
-------
bool
"""
# check for a compatible nested tuple and multiindexes among the axes
if not isinstance(tup, tuple):
return False
for i, k in enumerate(tup):
if is_list_like(k) or isinstance(k, slice):
return isinstance(labels, ABCMultiIndex)
return False
def is_label_like(key) -> bool:
"""
Returns
-------
bool
"""
# select a label or row
return not isinstance(key, slice) and not is_list_like_indexer(key)
def need_slice(obj) -> bool:
"""
Returns
-------
bool
"""
return (
obj.start is not None
or obj.stop is not None
or (obj.step is not None and obj.step != 1)
)
def _non_reducing_slice(slice_):
"""
Ensurse that a slice doesn't reduce to a Series or Scalar.
Any user-paseed `subset` should have this called on it
to make sure we're always working with DataFrames.
"""
# default to column slice, like DataFrame
# ['A', 'B'] -> IndexSlices[:, ['A', 'B']]
kinds = (ABCSeries, np.ndarray, Index, list, str)
if isinstance(slice_, kinds):
slice_ = IndexSlice[:, slice_]
def pred(part) -> bool:
"""
Returns
-------
bool
True if slice does *not* reduce,
False if `part` is a tuple.
"""
# true when slice does *not* reduce, False when part is a tuple,
# i.e. MultiIndex slice
return (isinstance(part, slice) or is_list_like(part)) and not isinstance(
part, tuple
)
if not is_list_like(slice_):
if not isinstance(slice_, slice):
# a 1-d slice, like df.loc[1]
slice_ = [[slice_]]
else:
# slice(a, b, c)
slice_ = [slice_] # to tuplize later
else:
slice_ = [part if pred(part) else [part] for part in slice_]
return tuple(slice_)
def _maybe_numeric_slice(df, slice_, include_bool=False):
"""
Want nice defaults for background_gradient that don't break
with non-numeric data. But if slice_ is passed go with that.
"""
if slice_ is None:
dtypes = [np.number]
if include_bool:
dtypes.append(bool)
slice_ = IndexSlice[:, df.select_dtypes(include=dtypes).columns]
return slice_
def _can_do_equal_len(labels, value, plane_indexer, lplane_indexer, obj) -> bool:
"""
Returns
-------
bool
True if we have an equal len settable.
"""
if not len(labels) == 1 or not np.iterable(value) or is_scalar(plane_indexer[0]):
return False
item = labels[0]
index = obj[item].index
values_len = len(value)
# equal len list/ndarray
if len(index) == values_len:
return True
elif lplane_indexer == values_len:
return True
return False
from typing import Hashable, List, Tuple, Union
import numpy as np
from pandas._libs.indexing import _NDFrameIndexerBase
from pandas._libs.lib import item_from_zerodim
from pandas.errors import AbstractMethodError
from pandas.util._decorators import Appender
from pandas.core.dtypes.common import (
is_float,
is_integer,
is_iterator,
is_list_like,
is_numeric_dtype,
is_scalar,
is_sequence,
)
from pandas.core.dtypes.concat import concat_compat
from pandas.core.dtypes.generic import ABCDataFrame, ABCMultiIndex, ABCSeries
from pandas.core.dtypes.missing import _infer_fill_value, isna
import pandas.core.common as com
from pandas.core.indexers import (
check_array_indexer,
is_list_like_indexer,
length_of_indexer,
)
from pandas.core.indexes.api import Index
from pandas.core.indexes.base import InvalidIndexError
# "null slice"
_NS = slice(None, None)
# the public IndexSlicerMaker
class _IndexSlice:
"""
Create an object to more easily perform multi-index slicing.
See Also
--------
MultiIndex.remove_unused_levels : New MultiIndex with no unused levels.
Notes
-----
See :ref:`Defined Levels <advanced.shown_levels>`
for further info on slicing a MultiIndex.
Examples
--------
>>> midx = pd.MultiIndex.from_product([['A0','A1'], ['B0','B1','B2','B3']])
>>> columns = ['foo', 'bar']
>>> dfmi = pd.DataFrame(np.arange(16).reshape((len(midx), len(columns))),
index=midx, columns=columns)
Using the default slice command:
>>> dfmi.loc[(slice(None), slice('B0', 'B1')), :]
foo bar
A0 B0 0 1
B1 2 3
A1 B0 8 9
B1 10 11
Using the IndexSlice class for a more intuitive command:
>>> idx = pd.IndexSlice
>>> dfmi.loc[idx[:, 'B0':'B1'], :]
foo bar
A0 B0 0 1
B1 2 3
A1 B0 8 9
B1 10 11
"""
def __getitem__(self, arg):
return arg
IndexSlice = _IndexSlice()
class IndexingError(Exception):
pass
class IndexingMixin:
"""Mixin for adding .loc/.iloc/.at/.iat to Datafames and Series.
"""
@property
def iloc(self) -> "_iLocIndexer":
"""
Purely integer-location based indexing for selection by position.
``.iloc[]`` is primarily integer position based (from ``0`` to
``length-1`` of the axis), but may also be used with a boolean
array.
Allowed inputs are:
- An integer, e.g. ``5``.
- A list or array of integers, e.g. ``[4, 3, 0]``.
- A slice object with ints, e.g. ``1:7``.
- A boolean array.
- A ``callable`` function with one argument (the calling Series or
DataFrame) and that returns valid output for indexing (one of the above).
This is useful in method chains, when you don't have a reference to the
calling object, but would like to base your selection on some value.
``.iloc`` will raise ``IndexError`` if a requested indexer is
out-of-bounds, except *slice* indexers which allow out-of-bounds
indexing (this conforms with python/numpy *slice* semantics).
See more at :ref:`Selection by Position <indexing.integer>`.
See Also
--------
DataFrame.iat : Fast integer location scalar accessor.
DataFrame.loc : Purely label-location based indexer for selection by label.
Series.iloc : Purely integer-location based indexing for
selection by position.
Examples
--------
>>> mydict = [{'a': 1, 'b': 2, 'c': 3, 'd': 4},
... {'a': 100, 'b': 200, 'c': 300, 'd': 400},
... {'a': 1000, 'b': 2000, 'c': 3000, 'd': 4000 }]
>>> df = pd.DataFrame(mydict)
>>> df
a b c d
0 1 2 3 4
1 100 200 300 400
2 1000 2000 3000 4000
**Indexing just the rows**
With a scalar integer.
>>> type(df.iloc[0])
<class 'pandas.core.series.Series'>
>>> df.iloc[0]
a 1
b 2
c 3
d 4
Name: 0, dtype: int64
With a list of integers.
>>> df.iloc[[0]]
a b c d
0 1 2 3 4
>>> type(df.iloc[[0]])
<class 'pandas.core.frame.DataFrame'>
>>> df.iloc[[0, 1]]
a b c d
0 1 2 3 4
1 100 200 300 400
With a `slice` object.
>>> df.iloc[:3]
a b c d
0 1 2 3 4
1 100 200 300 400
2 1000 2000 3000 4000
With a boolean mask the same length as the index.
>>> df.iloc[[True, False, True]]
a b c d
0 1 2 3 4
2 1000 2000 3000 4000
With a callable, useful in method chains. The `x` passed
to the ``lambda`` is the DataFrame being sliced. This selects
the rows whose index label even.
>>> df.iloc[lambda x: x.index % 2 == 0]
a b c d
0 1 2 3 4
2 1000 2000 3000 4000
**Indexing both axes**
You can mix the indexer types for the index and columns. Use ``:`` to
select the entire axis.
With scalar integers.
>>> df.iloc[0, 1]
2
With lists of integers.
>>> df.iloc[[0, 2], [1, 3]]
b d
0 2 4
2 2000 4000
With `slice` objects.
>>> df.iloc[1:3, 0:3]
a b c
1 100 200 300
2 1000 2000 3000
With a boolean array whose length matches the columns.
>>> df.iloc[:, [True, False, True, False]]
a c
0 1 3
1 100 300
2 1000 3000
With a callable function that expects the Series or DataFrame.
>>> df.iloc[:, lambda df: [0, 2]]
a c
0 1 3
1 100 300
2 1000 3000
"""
return _iLocIndexer("iloc", self)
@property
def loc(self) -> "_LocIndexer":
"""
Access a group of rows and columns by label(s) or a boolean array.
``.loc[]`` is primarily label based, but may also be used with a
boolean array.
Allowed inputs are:
- A single label, e.g. ``5`` or ``'a'``, (note that ``5`` is
interpreted as a *label* of the index, and **never** as an
integer position along the index).
- A list or array of labels, e.g. ``['a', 'b', 'c']``.
- A slice object with labels, e.g. ``'a':'f'``.
.. warning:: Note that contrary to usual python slices, **both** the
start and the stop are included
- A boolean array of the same length as the axis being sliced,
e.g. ``[True, False, True]``.
- A ``callable`` function with one argument (the calling Series or
DataFrame) and that returns valid output for indexing (one of the above)
See more at :ref:`Selection by Label <indexing.label>`
Raises
------
KeyError
If any items are not found.
See Also
--------
DataFrame.at : Access a single value for a row/column label pair.
DataFrame.iloc : Access group of rows and columns by integer position(s).
DataFrame.xs : Returns a cross-section (row(s) or column(s)) from the
Series/DataFrame.
Series.loc : Access group of values using labels.
Examples
--------
**Getting values**
>>> df = pd.DataFrame([[1, 2], [4, 5], [7, 8]],
... index=['cobra', 'viper', 'sidewinder'],
... columns=['max_speed', 'shield'])
>>> df
max_speed shield
cobra 1 2
viper 4 5
sidewinder 7 8
Single label. Note this returns the row as a Series.
>>> df.loc['viper']
max_speed 4
shield 5
Name: viper, dtype: int64
List of labels. Note using ``[[]]`` returns a DataFrame.
>>> df.loc[['viper', 'sidewinder']]
max_speed shield
viper 4 5
sidewinder 7 8
Single label for row and column
>>> df.loc['cobra', 'shield']
2
Slice with labels for row and single label for column. As mentioned
above, note that both the start and stop of the slice are included.
>>> df.loc['cobra':'viper', 'max_speed']
cobra 1
viper 4
Name: max_speed, dtype: int64
Boolean list with the same length as the row axis
>>> df.loc[[False, False, True]]
max_speed shield
sidewinder 7 8
Conditional that returns a boolean Series
>>> df.loc[df['shield'] > 6]
max_speed shield
sidewinder 7 8
Conditional that returns a boolean Series with column labels specified
>>> df.loc[df['shield'] > 6, ['max_speed']]
max_speed
sidewinder 7
Callable that returns a boolean Series
>>> df.loc[lambda df: df['shield'] == 8]
max_speed shield
sidewinder 7 8
**Setting values**
Set value for all items matching the list of labels
>>> df.loc[['viper', 'sidewinder'], ['shield']] = 50
>>> df
max_speed shield
cobra 1 2
viper 4 50
sidewinder 7 50
Set value for an entire row
>>> df.loc['cobra'] = 10
>>> df
max_speed shield
cobra 10 10
viper 4 50
sidewinder 7 50
Set value for an entire column
>>> df.loc[:, 'max_speed'] = 30
>>> df
max_speed shield
cobra 30 10
viper 30 50
sidewinder 30 50
Set value for rows matching callable condition
>>> df.loc[df['shield'] > 35] = 0
>>> df
max_speed shield
cobra 30 10
viper 0 0
sidewinder 0 0
**Getting values on a DataFrame with an index that has integer labels**
Another example using integers for the index
>>> df = pd.DataFrame([[1, 2], [4, 5], [7, 8]],
... index=[7, 8, 9], columns=['max_speed', 'shield'])
>>> df
max_speed shield
7 1 2
8 4 5
9 7 8
Slice with integer labels for rows. As mentioned above, note that both
the start and stop of the slice are included.
>>> df.loc[7:9]
max_speed shield
7 1 2
8 4 5
9 7 8
**Getting values with a MultiIndex**
A number of examples using a DataFrame with a MultiIndex
>>> tuples = [
... ('cobra', 'mark i'), ('cobra', 'mark ii'),
... ('sidewinder', 'mark i'), ('sidewinder', 'mark ii'),
... ('viper', 'mark ii'), ('viper', 'mark iii')
... ]
>>> index = pd.MultiIndex.from_tuples(tuples)
>>> values = [[12, 2], [0, 4], [10, 20],
... [1, 4], [7, 1], [16, 36]]
>>> df = pd.DataFrame(values, columns=['max_speed', 'shield'], index=index)
>>> df
max_speed shield
cobra mark i 12 2
mark ii 0 4
sidewinder mark i 10 20
mark ii 1 4
viper mark ii 7 1
mark iii 16 36
Single label. Note this returns a DataFrame with a single index.
>>> df.loc['cobra']
max_speed shield
mark i 12 2
mark ii 0 4
Single index tuple. Note this returns a Series.
>>> df.loc[('cobra', 'mark ii')]
max_speed 0
shield 4
Name: (cobra, mark ii), dtype: int64
Single label for row and column. Similar to passing in a tuple, this
returns a Series.
>>> df.loc['cobra', 'mark i']
max_speed 12
shield 2
Name: (cobra, mark i), dtype: int64
Single tuple. Note using ``[[]]`` returns a DataFrame.
>>> df.loc[[('cobra', 'mark ii')]]
max_speed shield
cobra mark ii 0 4
Single tuple for the index with a single label for the column
>>> df.loc[('cobra', 'mark i'), 'shield']
2
Slice from index tuple to single label
>>> df.loc[('cobra', 'mark i'):'viper']
max_speed shield
cobra mark i 12 2
mark ii 0 4
sidewinder mark i 10 20
mark ii 1 4
viper mark ii 7 1
mark iii 16 36
Slice from index tuple to index tuple
>>> df.loc[('cobra', 'mark i'):('viper', 'mark ii')]
max_speed shield
cobra mark i 12 2
mark ii 0 4
sidewinder mark i 10 20
mark ii 1 4
viper mark ii 7 1
"""
return _LocIndexer("loc", self)
@property
def at(self) -> "_AtIndexer":
"""
Access a single value for a row/column label pair.
Similar to ``loc``, in that both provide label-based lookups. Use
``at`` if you only need to get or set a single value in a DataFrame
or Series.
Raises
------
KeyError
If 'label' does not exist in DataFrame.
See Also
--------
DataFrame.iat : Access a single value for a row/column pair by integer
position.
DataFrame.loc : Access a group of rows and columns by label(s).
Series.at : Access a single value using a label.
Examples
--------
>>> df = pd.DataFrame([[0, 2, 3], [0, 4, 1], [10, 20, 30]],
... index=[4, 5, 6], columns=['A', 'B', 'C'])
>>> df
A B C
4 0 2 3
5 0 4 1
6 10 20 30
Get value at specified row/column pair
>>> df.at[4, 'B']
2
Set value at specified row/column pair
>>> df.at[4, 'B'] = 10
>>> df.at[4, 'B']
10
Get value within a Series
>>> df.loc[5].at['B']
4
"""
return _AtIndexer("at", self)
@property
def iat(self) -> "_iAtIndexer":
"""
Access a single value for a row/column pair by integer position.
Similar to ``iloc``, in that both provide integer-based lookups. Use
``iat`` if you only need to get or set a single value in a DataFrame
or Series.
Raises
------
IndexError
When integer position is out of bounds.
See Also
--------
DataFrame.at : Access a single value for a row/column label pair.
DataFrame.loc : Access a group of rows and columns by label(s).
DataFrame.iloc : Access a group of rows and columns by integer position(s).
Examples
--------
>>> df = pd.DataFrame([[0, 2, 3], [0, 4, 1], [10, 20, 30]],
... columns=['A', 'B', 'C'])
>>> df
A B C
0 0 2 3
1 0 4 1
2 10 20 30
Get value at specified row/column pair
>>> df.iat[1, 2]
1
Set value at specified row/column pair
>>> df.iat[1, 2] = 10
>>> df.iat[1, 2]
10
Get value within a series
>>> df.loc[0].iat[1]
2
"""
return _iAtIndexer("iat", self)
class _NDFrameIndexer(_NDFrameIndexerBase):
_valid_types: str
axis = None
def __call__(self, axis=None):
# we need to return a copy of ourselves
new_self = type(self)(self.name, self.obj)
if axis is not None:
axis = self.obj._get_axis_number(axis)
new_self.axis = axis
return new_self
def _get_label(self, label, axis: int):
if self.ndim == 1:
# for perf reasons we want to try _xs first
# as its basically direct indexing
# but will fail when the index is not present
# see GH5667
return self.obj._xs(label, axis=axis)
elif isinstance(label, tuple) and isinstance(label[axis], slice):
raise IndexingError("no slices here, handle elsewhere")
return self.obj._xs(label, axis=axis)
def _get_loc(self, key: int, axis: int):
return self.obj._ixs(key, axis=axis)
def _slice(self, obj, axis: int, kind=None):
return self.obj._slice(obj, axis=axis, kind=kind)
def _get_setitem_indexer(self, key):
if self.axis is not None:
return self._convert_tuple(key)
ax = self.obj._get_axis(0)
if isinstance(ax, ABCMultiIndex) and self.name != "iloc":
try:
return ax.get_loc(key)
except (TypeError, KeyError, InvalidIndexError):
# TypeError e.g. passed a bool
pass
if isinstance(key, tuple):
try:
return self._convert_tuple(key)
except IndexingError:
pass
if isinstance(key, range):
return list(key)
try:
return self._convert_to_indexer(key, axis=0)
except TypeError as e:
# invalid indexer type vs 'other' indexing errors
if "cannot do" in str(e):
raise
raise IndexingError(key)
def __setitem__(self, key, value):
if isinstance(key, tuple):
key = tuple(com.apply_if_callable(x, self.obj) for x in key)
else:
key = com.apply_if_callable(key, self.obj)
indexer = self._get_setitem_indexer(key)
self._setitem_with_indexer(indexer, value)
def _validate_key(self, key, axis: int):
"""
Ensure that key is valid for current indexer.
Parameters
----------
key : scalar, slice or list-like
Key requested.
axis : int
Dimension on which the indexing is being made.
Raises
------
TypeError
If the key (or some element of it) has wrong type.
IndexError
If the key (or some element of it) is out of bounds.
KeyError
If the key was not found.
"""
raise AbstractMethodError(self)
def _has_valid_tuple(self, key: Tuple):
"""
Check the key for valid keys across my indexer.
"""
for i, k in enumerate(key):
if i >= self.ndim:
raise IndexingError("Too many indexers")
try:
self._validate_key(k, i)
except ValueError:
raise ValueError(
"Location based indexing can only have "
f"[{self._valid_types}] types"
)
def _is_nested_tuple_indexer(self, tup: Tuple) -> bool:
"""
Returns
-------
bool
"""
if any(isinstance(ax, ABCMultiIndex) for ax in self.obj.axes):
return any(is_nested_tuple(tup, ax) for ax in self.obj.axes)
return False
def _convert_tuple(self, key):
keyidx = []
if self.axis is not None:
axis = self.obj._get_axis_number(self.axis)
for i in range(self.ndim):
if i == axis:
keyidx.append(self._convert_to_indexer(key, axis=axis))
else:
keyidx.append(slice(None))
else:
for i, k in enumerate(key):
if i >= self.ndim:
raise IndexingError("Too many indexers")
idx = self._convert_to_indexer(k, axis=i)
keyidx.append(idx)
return tuple(keyidx)
def _convert_scalar_indexer(self, key, axis: int):
# if we are accessing via lowered dim, use the last dim
ax = self.obj._get_axis(min(axis, self.ndim - 1))
# a scalar
return ax._convert_scalar_indexer(key, kind=self.name)
def _convert_slice_indexer(self, key: slice, axis: int):
# if we are accessing via lowered dim, use the last dim
ax = self.obj._get_axis(min(axis, self.ndim - 1))
return ax._convert_slice_indexer(key, kind=self.name)
def _has_valid_setitem_indexer(self, indexer) -> bool:
return True
def _has_valid_positional_setitem_indexer(self, indexer) -> bool:
"""
Validate that a positional indexer cannot enlarge its target
will raise if needed, does not modify the indexer externally.
Returns
-------
bool
"""
if isinstance(indexer, dict):
raise IndexError(f"{self.name} cannot enlarge its target object")
else:
if not isinstance(indexer, tuple):
indexer = _tuplify(self.ndim, indexer)
for ax, i in zip(self.obj.axes, indexer):
if isinstance(i, slice):
# should check the stop slice?
pass
elif is_list_like_indexer(i):
# should check the elements?
pass
elif is_integer(i):
if i >= len(ax):
raise IndexError(
f"{self.name} cannot enlarge its target object"
)
elif isinstance(i, dict):
raise IndexError(f"{self.name} cannot enlarge its target object")
return True
def _setitem_with_indexer(self, indexer, value):
self._has_valid_setitem_indexer(indexer)
# also has the side effect of consolidating in-place
from pandas import Series
info_axis = self.obj._info_axis_number
# maybe partial set
take_split_path = self.obj._is_mixed_type
# if there is only one block/type, still have to take split path
# unless the block is one-dimensional or it can hold the value
if not take_split_path and self.obj._data.blocks:
(blk,) = self.obj._data.blocks
if 1 < blk.ndim: # in case of dict, keys are indices
val = list(value.values()) if isinstance(value, dict) else value
take_split_path = not blk._can_hold_element(val)
# if we have any multi-indexes that have non-trivial slices
# (not null slices) then we must take the split path, xref
# GH 10360, GH 27841
if isinstance(indexer, tuple) and len(indexer) == len(self.obj.axes):
for i, ax in zip(indexer, self.obj.axes):
if isinstance(ax, ABCMultiIndex) and not (
is_integer(i) or com.is_null_slice(i)
):
take_split_path = True
break
if isinstance(indexer, tuple):
nindexer = []
for i, idx in enumerate(indexer):
if isinstance(idx, dict):
# reindex the axis to the new value
# and set inplace
key, _ = convert_missing_indexer(idx)
# if this is the items axes, then take the main missing
# path first
# this correctly sets the dtype and avoids cache issues
# essentially this separates out the block that is needed
# to possibly be modified
if self.ndim > 1 and i == self.obj._info_axis_number:
# add the new item, and set the value
# must have all defined axes if we have a scalar
# or a list-like on the non-info axes if we have a
# list-like
len_non_info_axes = (
len(_ax) for _i, _ax in enumerate(self.obj.axes) if _i != i
)
if any(not l for l in len_non_info_axes):
if not is_list_like_indexer(value):
raise ValueError(
"cannot set a frame with no "
"defined index and a scalar"
)
self.obj[key] = value
return self.obj
# add a new item with the dtype setup
self.obj[key] = _infer_fill_value(value)
new_indexer = convert_from_missing_indexer_tuple(
indexer, self.obj.axes
)
self._setitem_with_indexer(new_indexer, value)
return self.obj
# reindex the axis
# make sure to clear the cache because we are
# just replacing the block manager here
# so the object is the same
index = self.obj._get_axis(i)
labels = index.insert(len(index), key)
self.obj._data = self.obj.reindex(labels, axis=i)._data
self.obj._maybe_update_cacher(clear=True)
self.obj._is_copy = None
nindexer.append(labels.get_loc(key))
else:
nindexer.append(idx)
indexer = tuple(nindexer)
else:
indexer, missing = convert_missing_indexer(indexer)
if missing:
return self._setitem_with_indexer_missing(indexer, value)
# set
item_labels = self.obj._get_axis(info_axis)
# align and set the values
if take_split_path:
# Above we only set take_split_path to True for 2D cases
assert self.ndim == 2
assert info_axis == 1
if not isinstance(indexer, tuple):
indexer = _tuplify(self.ndim, indexer)
if isinstance(value, ABCSeries):
value = self._align_series(indexer, value)
info_idx = indexer[info_axis]
if is_integer(info_idx):
info_idx = [info_idx]
labels = item_labels[info_idx]
# if we have a partial multiindex, then need to adjust the plane
# indexer here
if len(labels) == 1 and isinstance(
self.obj[labels[0]].axes[0], ABCMultiIndex
):
item = labels[0]
obj = self.obj[item]
index = obj.index
idx = indexer[:info_axis][0]
plane_indexer = tuple([idx]) + indexer[info_axis + 1 :]
lplane_indexer = length_of_indexer(plane_indexer[0], index)
# require that we are setting the right number of values that
# we are indexing
if (
is_list_like_indexer(value)
and np.iterable(value)
and lplane_indexer != len(value)
):
if len(obj[idx]) != len(value):
raise ValueError(
"cannot set using a multi-index "
"selection indexer with a different "
"length than the value"
)
# make sure we have an ndarray
value = getattr(value, "values", value).ravel()
# we can directly set the series here
# as we select a slice indexer on the mi
idx = index._convert_slice_indexer(idx)
obj._consolidate_inplace()
obj = obj.copy()
obj._data = obj._data.setitem(indexer=tuple([idx]), value=value)
self.obj[item] = obj
return
# non-mi
else:
plane_indexer = indexer[:info_axis] + indexer[info_axis + 1 :]
plane_axis = self.obj.axes[:info_axis][0]
lplane_indexer = length_of_indexer(plane_indexer[0], plane_axis)
def setter(item, v):
s = self.obj[item]
pi = plane_indexer[0] if lplane_indexer == 1 else plane_indexer
# perform the equivalent of a setitem on the info axis
# as we have a null slice or a slice with full bounds
# which means essentially reassign to the columns of a
# multi-dim object
# GH6149 (null slice), GH10408 (full bounds)
if isinstance(pi, tuple) and all(
com.is_null_slice(idx) or com.is_full_slice(idx, len(self.obj))
for idx in pi
):
s = v
else:
# set the item, possibly having a dtype change
s._consolidate_inplace()
s = s.copy()
s._data = s._data.setitem(indexer=pi, value=v)
s._maybe_update_cacher(clear=True)
# reset the sliced object if unique
self.obj[item] = s
# we need an iterable, with a ndim of at least 1
# eg. don't pass through np.array(0)
if is_list_like_indexer(value) and getattr(value, "ndim", 1) > 0:
# we have an equal len Frame
if isinstance(value, ABCDataFrame):
sub_indexer = list(indexer)
multiindex_indexer = isinstance(labels, ABCMultiIndex)
for item in labels:
if item in value:
sub_indexer[info_axis] = item
v = self._align_series(
tuple(sub_indexer), value[item], multiindex_indexer
)
else:
v = np.nan
setter(item, v)
# we have an equal len ndarray/convertible to our labels
# hasattr first, to avoid coercing to ndarray without reason.
# But we may be relying on the ndarray coercion to check ndim.
# Why not just convert to an ndarray earlier on if needed?
elif np.ndim(value) == 2:
# note that this coerces the dtype if we are mixed
# GH 7551
value = np.array(value, dtype=object)
if len(labels) != value.shape[1]:
raise ValueError(
"Must have equal len keys and value "
"when setting with an ndarray"
)
for i, item in enumerate(labels):
# setting with a list, recoerces
setter(item, value[:, i].tolist())
# we have an equal len list/ndarray
elif _can_do_equal_len(
labels, value, plane_indexer, lplane_indexer, self.obj
):
setter(labels[0], value)
# per label values
else:
if len(labels) != len(value):
raise ValueError(
"Must have equal len keys and value "
"when setting with an iterable"
)
for item, v in zip(labels, value):
setter(item, v)
else:
# scalar
for item in labels:
setter(item, value)
else:
if isinstance(indexer, tuple):
indexer = maybe_convert_ix(*indexer)
# if we are setting on the info axis ONLY
# set using those methods to avoid block-splitting
# logic here
if (
len(indexer) > info_axis
and is_integer(indexer[info_axis])
and all(
com.is_null_slice(idx)
for i, idx in enumerate(indexer)
if i != info_axis
)
and item_labels.is_unique
):
self.obj[item_labels[indexer[info_axis]]] = value
return
if isinstance(value, (ABCSeries, dict)):
# TODO(EA): ExtensionBlock.setitem this causes issues with
# setting for extensionarrays that store dicts. Need to decide
# if it's worth supporting that.
value = self._align_series(indexer, Series(value))
elif isinstance(value, ABCDataFrame):
value = self._align_frame(indexer, value)
# check for chained assignment
self.obj._check_is_chained_assignment_possible()
# actually do the set
self.obj._consolidate_inplace()
self.obj._data = self.obj._data.setitem(indexer=indexer, value=value)
self.obj._maybe_update_cacher(clear=True)
def _setitem_with_indexer_missing(self, indexer, value):
"""
Insert new row(s) or column(s) into the Series or DataFrame.
"""
from pandas import Series
# reindex the axis to the new value
# and set inplace
if self.ndim == 1:
index = self.obj.index
new_index = index.insert(len(index), indexer)
# we have a coerced indexer, e.g. a float
# that matches in an Int64Index, so
# we will not create a duplicate index, rather
# index to that element
# e.g. 0.0 -> 0
# GH#12246
if index.is_unique:
new_indexer = index.get_indexer([new_index[-1]])
if (new_indexer != -1).any():
return self._setitem_with_indexer(new_indexer, value)
# this preserves dtype of the value
new_values = Series([value])._values
if len(self.obj._values):
# GH#22717 handle casting compatibility that np.concatenate
# does incorrectly
new_values = concat_compat([self.obj._values, new_values])
self.obj._data = self.obj._constructor(
new_values, index=new_index, name=self.obj.name
)._data
self.obj._maybe_update_cacher(clear=True)
return self.obj
elif self.ndim == 2:
if not len(self.obj.columns):
# no columns and scalar
raise ValueError("cannot set a frame with no defined columns")
if isinstance(value, ABCSeries):
# append a Series
value = value.reindex(index=self.obj.columns, copy=True)
value.name = indexer
else:
# a list-list
if is_list_like_indexer(value):
# must have conforming columns
if len(value) != len(self.obj.columns):
raise ValueError("cannot set a row with mismatched columns")
value = Series(value, index=self.obj.columns, name=indexer)
self.obj._data = self.obj.append(value)._data
self.obj._maybe_update_cacher(clear=True)
return self.obj
def _align_series(self, indexer, ser: ABCSeries, multiindex_indexer: bool = False):
"""
Parameters
----------
indexer : tuple, slice, scalar
Indexer used to get the locations that will be set to `ser`.
ser : pd.Series
Values to assign to the locations specified by `indexer`.
multiindex_indexer : boolean, optional
Defaults to False. Should be set to True if `indexer` was from
a `pd.MultiIndex`, to avoid unnecessary broadcasting.
Returns
-------
`np.array` of `ser` broadcast to the appropriate shape for assignment
to the locations selected by `indexer`
"""
if isinstance(indexer, (slice, np.ndarray, list, Index)):
indexer = tuple([indexer])
if isinstance(indexer, tuple):
# flatten np.ndarray indexers
def ravel(i):
return i.ravel() if isinstance(i, np.ndarray) else i
indexer = tuple(map(ravel, indexer))
aligners = [not com.is_null_slice(idx) for idx in indexer]
sum_aligners = sum(aligners)
single_aligner = sum_aligners == 1
is_frame = self.ndim == 2
obj = self.obj
# are we a single alignable value on a non-primary
# dim (e.g. panel: 1,2, or frame: 0) ?
# hence need to align to a single axis dimension
# rather that find all valid dims
# frame
if is_frame:
single_aligner = single_aligner and aligners[0]
# we have a frame, with multiple indexers on both axes; and a
# series, so need to broadcast (see GH5206)
if sum_aligners == self.ndim and all(is_sequence(_) for _ in indexer):
ser = ser.reindex(obj.axes[0][indexer[0]], copy=True)._values
# single indexer
if len(indexer) > 1 and not multiindex_indexer:
len_indexer = len(indexer[1])
ser = np.tile(ser, len_indexer).reshape(len_indexer, -1).T
return ser
for i, idx in enumerate(indexer):
ax = obj.axes[i]
# multiple aligners (or null slices)
if is_sequence(idx) or isinstance(idx, slice):
if single_aligner and com.is_null_slice(idx):
continue
new_ix = ax[idx]
if not is_list_like_indexer(new_ix):
new_ix = Index([new_ix])
else:
new_ix = Index(new_ix)
if ser.index.equals(new_ix) or not len(new_ix):
return ser._values.copy()
return ser.reindex(new_ix)._values
# 2 dims
elif single_aligner:
# reindex along index
ax = self.obj.axes[1]
if ser.index.equals(ax) or not len(ax):
return ser._values.copy()
return ser.reindex(ax)._values
elif is_scalar(indexer):
ax = self.obj._get_axis(1)
if ser.index.equals(ax):
return ser._values.copy()
return ser.reindex(ax)._values
raise ValueError("Incompatible indexer with Series")
def _align_frame(self, indexer, df: ABCDataFrame):
is_frame = self.ndim == 2
if isinstance(indexer, tuple):
idx, cols = None, None
sindexers = []
for i, ix in enumerate(indexer):
ax = self.obj.axes[i]
if is_sequence(ix) or isinstance(ix, slice):
if isinstance(ix, np.ndarray):
ix = ix.ravel()
if idx is None:
idx = ax[ix]
elif cols is None:
cols = ax[ix]
else:
break
else:
sindexers.append(i)
if idx is not None and cols is not None:
if df.index.equals(idx) and df.columns.equals(cols):
val = df.copy()._values
else:
val = df.reindex(idx, columns=cols)._values
return val
elif (isinstance(indexer, slice) or is_list_like_indexer(indexer)) and is_frame:
ax = self.obj.index[indexer]
if df.index.equals(ax):
val = df.copy()._values
else:
# we have a multi-index and are trying to align
# with a particular, level GH3738
if (
isinstance(ax, ABCMultiIndex)
and isinstance(df.index, ABCMultiIndex)
and ax.nlevels != df.index.nlevels
):
raise TypeError(
"cannot align on a multi-index with out "
"specifying the join levels"
)
val = df.reindex(index=ax)._values
return val
raise ValueError("Incompatible indexer with DataFrame")
def _getitem_tuple(self, tup: Tuple):
try:
return self._getitem_lowerdim(tup)
except IndexingError:
pass
# no multi-index, so validate all of the indexers
self._has_valid_tuple(tup)
# ugly hack for GH #836
if self._multi_take_opportunity(tup):
return self._multi_take(tup)
# no shortcut needed
retval = self.obj
for i, key in enumerate(tup):
if com.is_null_slice(key):
continue
retval = getattr(retval, self.name)._getitem_axis(key, axis=i)
return retval
def _multi_take_opportunity(self, tup: Tuple) -> bool:
"""
Check whether there is the possibility to use ``_multi_take``.
Currently the limit is that all axes being indexed, must be indexed with
list-likes.
Parameters
----------
tup : tuple
Tuple of indexers, one per axis.
Returns
-------
bool
Whether the current indexing,
can be passed through `_multi_take`.
"""
if not all(is_list_like_indexer(x) for x in tup):
return False
# just too complicated
if any(com.is_bool_indexer(x) for x in tup):
return False
return True
def _multi_take(self, tup: Tuple):
"""
Create the indexers for the passed tuple of keys, and
executes the take operation. This allows the take operation to be
executed all at once, rather than once for each dimension.
Improving efficiency.
Parameters
----------
tup : tuple
Tuple of indexers, one per axis.
Returns
-------
values: same type as the object being indexed
"""
# GH 836
o = self.obj
d = {
axis: self._get_listlike_indexer(key, axis)
for (key, axis) in zip(tup, o._AXIS_ORDERS)
}
return o._reindex_with_indexers(d, copy=True, allow_dups=True)
def _handle_lowerdim_multi_index_axis0(self, tup: Tuple):
# we have an axis0 multi-index, handle or raise
axis = self.axis or 0
try:
# fast path for series or for tup devoid of slices
return self._get_label(tup, axis=axis)
except TypeError:
# slices are unhashable
pass
except KeyError as ek:
# raise KeyError if number of indexers match
# else IndexingError will be raised
if len(tup) <= self.obj.index.nlevels and len(tup) > self.ndim:
raise ek
return None
def _getitem_lowerdim(self, tup: Tuple):
# we can directly get the axis result since the axis is specified
if self.axis is not None:
axis = self.obj._get_axis_number(self.axis)
return self._getitem_axis(tup, axis=axis)
# we may have a nested tuples indexer here
if self._is_nested_tuple_indexer(tup):
return self._getitem_nested_tuple(tup)
# we maybe be using a tuple to represent multiple dimensions here
ax0 = self.obj._get_axis(0)
# ...but iloc should handle the tuple as simple integer-location
# instead of checking it as multiindex representation (GH 13797)
if isinstance(ax0, ABCMultiIndex) and self.name != "iloc":
result = self._handle_lowerdim_multi_index_axis0(tup)
if result is not None:
return result
if len(tup) > self.ndim:
raise IndexingError("Too many indexers. handle elsewhere")
for i, key in enumerate(tup):
if is_label_like(key) or isinstance(key, tuple):
section = self._getitem_axis(key, axis=i)
# we have yielded a scalar ?
if not is_list_like_indexer(section):
return section
elif section.ndim == self.ndim:
# we're in the middle of slicing through a MultiIndex
# revise the key wrt to `section` by inserting an _NS
new_key = tup[:i] + (_NS,) + tup[i + 1 :]
else:
new_key = tup[:i] + tup[i + 1 :]
# unfortunately need an odious kludge here because of
# DataFrame transposing convention
if (
isinstance(section, ABCDataFrame)
and i > 0
and len(new_key) == 2
):
a, b = new_key
new_key = b, a
if len(new_key) == 1:
new_key = new_key[0]
# Slices should return views, but calling iloc/loc with a null
# slice returns a new object.
if com.is_null_slice(new_key):
return section
# This is an elided recursive call to iloc/loc/etc'
return getattr(section, self.name)[new_key]
raise IndexingError("not applicable")
def _getitem_nested_tuple(self, tup: Tuple):
# we have a nested tuple so have at least 1 multi-index level
# we should be able to match up the dimensionality here
# we have too many indexers for our dim, but have at least 1
# multi-index dimension, try to see if we have something like
# a tuple passed to a series with a multi-index
if len(tup) > self.ndim:
result = self._handle_lowerdim_multi_index_axis0(tup)
if result is not None:
return result
# this is a series with a multi-index specified a tuple of
# selectors
axis = self.axis or 0
return self._getitem_axis(tup, axis=axis)
# handle the multi-axis by taking sections and reducing
# this is iterative
obj = self.obj
axis = 0
for i, key in enumerate(tup):
if com.is_null_slice(key):
axis += 1
continue
current_ndim = obj.ndim
obj = getattr(obj, self.name)._getitem_axis(key, axis=axis)
axis += 1
# if we have a scalar, we are done
if is_scalar(obj) or not hasattr(obj, "ndim"):
break
# has the dim of the obj changed?
# GH 7199
if obj.ndim < current_ndim:
axis -= 1
return obj
def _get_listlike_indexer(self, key, axis: int, raise_missing: bool = False):
"""
Transform a list-like of keys into a new index and an indexer.
Parameters
----------
key : list-like
Targeted labels.
axis: int
Dimension on which the indexing is being made.
raise_missing: bool, default False
Whether to raise a KeyError if some labels were not found.
Will be removed in the future, and then this method will always behave as
if ``raise_missing=True``.
Raises
------
KeyError
If at least one key was requested but none was found, and
raise_missing=True.
Returns
-------
keyarr: Index
New index (coinciding with 'key' if the axis is unique).
values : array-like
Indexer for the return object, -1 denotes keys not found.
"""
o = self.obj
ax = o._get_axis(axis)
# Have the index compute an indexer or return None
# if it cannot handle:
indexer, keyarr = ax._convert_listlike_indexer(key, kind=self.name)
# We only act on all found values:
if indexer is not None and (indexer != -1).all():
self._validate_read_indexer(key, indexer, axis, raise_missing=raise_missing)
return ax[indexer], indexer
if ax.is_unique and not getattr(ax, "is_overlapping", False):
indexer = ax.get_indexer_for(key)
keyarr = ax.reindex(keyarr)[0]
else:
keyarr, indexer, new_indexer = ax._reindex_non_unique(keyarr)
self._validate_read_indexer(keyarr, indexer, axis, raise_missing=raise_missing)
return keyarr, indexer
def _getitem_iterable(self, key, axis: int):
"""
Index current object with an an iterable key.
The iterable key can be a boolean indexer or a collection of keys.
Parameters
----------
key : iterable
Targeted labels or boolean indexer.
axis: int
Dimension on which the indexing is being made.
Raises
------
KeyError
If no key was found. Will change in the future to raise if not all
keys were found.
IndexingError
If the boolean indexer is unalignable with the object being
indexed.
Returns
-------
scalar, DataFrame, or Series: indexed value(s).
"""
# caller is responsible for ensuring non-None axis
self._validate_key(key, axis)
labels = self.obj._get_axis(axis)
if com.is_bool_indexer(key):
# A boolean indexer
key = check_bool_indexer(labels, key)
(inds,) = key.nonzero()
return self.obj._take_with_is_copy(inds, axis=axis)
else:
# A collection of keys
keyarr, indexer = self._get_listlike_indexer(key, axis, raise_missing=False)
return self.obj._reindex_with_indexers(
{axis: [keyarr, indexer]}, copy=True, allow_dups=True
)
def _validate_read_indexer(
self, key, indexer, axis: int, raise_missing: bool = False
):
"""
Check that indexer can be used to return a result.
e.g. at least one element was found,
unless the list of keys was actually empty.
Parameters
----------
key : list-like
Targeted labels (only used to show correct error message).
indexer: array-like of booleans
Indices corresponding to the key,
(with -1 indicating not found).
axis: int
Dimension on which the indexing is being made.
raise_missing: bool
Whether to raise a KeyError if some labels are not found. Will be
removed in the future, and then this method will always behave as
if raise_missing=True.
Raises
------
KeyError
If at least one key was requested but none was found, and
raise_missing=True.
"""
ax = self.obj._get_axis(axis)
if len(key) == 0:
return
# Count missing values:
missing = (indexer < 0).sum()
if missing:
if missing == len(indexer):
axis_name = self.obj._get_axis_name(axis)
raise KeyError(f"None of [{key}] are in the [{axis_name}]")
# We (temporarily) allow for some missing keys with .loc, except in
# some cases (e.g. setting) in which "raise_missing" will be False
if not (self.name == "loc" and not raise_missing):
not_found = list(set(key) - set(ax))
raise KeyError(f"{not_found} not in index")
# we skip the warning on Categorical/Interval
# as this check is actually done (check for
# non-missing values), but a bit later in the
# code, so we want to avoid warning & then
# just raising
if not (ax.is_categorical() or ax.is_interval()):
raise KeyError(
"Passing list-likes to .loc or [] with any missing labels "
"is no longer supported, see "
"https://pandas.pydata.org/pandas-docs/stable/user_guide/indexing.html#deprecate-loc-reindex-listlike" # noqa:E501
)
def _convert_to_indexer(self, key, axis: int):
"""
Convert indexing key into something we can use to do actual fancy
indexing on a ndarray.
Examples
ix[:5] -> slice(0, 5)
ix[[1,2,3]] -> [1,2,3]
ix[['foo', 'bar', 'baz']] -> [i, j, k] (indices of foo, bar, baz)
Going by Zen of Python?
'In the face of ambiguity, refuse the temptation to guess.'
raise AmbiguousIndexError with integer labels?
- No, prefer label-based indexing
"""
labels = self.obj._get_axis(axis)
if isinstance(key, slice):
return self._convert_slice_indexer(key, axis)
# try to find out correct indexer, if not type correct raise
try:
key = self._convert_scalar_indexer(key, axis)
except TypeError:
# but we will allow setting
pass
# see if we are positional in nature
is_int_index = labels.is_integer()
is_int_positional = is_integer(key) and not is_int_index
if is_scalar(key) or isinstance(labels, ABCMultiIndex):
# Otherwise get_loc will raise InvalidIndexError
# if we are a label return me
try:
return labels.get_loc(key)
except LookupError:
if isinstance(key, tuple) and isinstance(labels, ABCMultiIndex):
if len(key) == labels.nlevels:
return {"key": key}
raise
except TypeError:
pass
except ValueError:
if not is_int_positional:
raise
# a positional
if is_int_positional:
# if we are setting and its not a valid location
# its an insert which fails by definition
if self.name == "loc":
# always valid
return {"key": key}
if key >= self.obj.shape[axis] and not isinstance(labels, ABCMultiIndex):
# a positional
raise ValueError("cannot set by positional indexing with enlargement")
return key
if is_nested_tuple(key, labels):
return labels.get_locs(key)
elif is_list_like_indexer(key):
if com.is_bool_indexer(key):
key = check_bool_indexer(labels, key)
(inds,) = key.nonzero()
return inds
else:
# When setting, missing keys are not allowed, even with .loc:
return self._get_listlike_indexer(key, axis, raise_missing=True)[1]
else:
try:
return labels.get_loc(key)
except LookupError:
# allow a not found key only if we are a setter
if not is_list_like_indexer(key):
return {"key": key}
raise
class _LocationIndexer(_NDFrameIndexer):
_takeable: bool = False
def __getitem__(self, key):
if type(key) is tuple:
key = tuple(com.apply_if_callable(x, self.obj) for x in key)
if self._is_scalar_access(key):
try:
return self.obj._get_value(*key, takeable=self._takeable)
except (KeyError, IndexError, AttributeError):
# AttributeError for IntervalTree get_value
pass
return self._getitem_tuple(key)
else:
# we by definition only have the 0th axis
axis = self.axis or 0
maybe_callable = com.apply_if_callable(key, self.obj)
return self._getitem_axis(maybe_callable, axis=axis)
def _is_scalar_access(self, key: Tuple):
raise NotImplementedError()
def _getitem_axis(self, key, axis: int):
raise NotImplementedError()
def _getbool_axis(self, key, axis: int):
# caller is responsible for ensuring non-None axis
labels = self.obj._get_axis(axis)
key = check_bool_indexer(labels, key)
inds = key.nonzero()[0]
return self.obj._take_with_is_copy(inds, axis=axis)
@Appender(IndexingMixin.loc.__doc__)
class _LocIndexer(_LocationIndexer):
_valid_types = (
"labels (MUST BE IN THE INDEX), slices of labels (BOTH "
"endpoints included! Can be slices of integers if the "
"index is integers), listlike of labels, boolean"
)
@Appender(_NDFrameIndexer._validate_key.__doc__)
def _validate_key(self, key, axis: int):
# valid for a collection of labels (we check their presence later)
# slice of labels (where start-end in labels)
# slice of integers (only if in the labels)
# boolean
if isinstance(key, slice):
return
if com.is_bool_indexer(key):
return
if not is_list_like_indexer(key):
self._convert_scalar_indexer(key, axis)
def _is_scalar_access(self, key: Tuple) -> bool:
"""
Returns
-------
bool
"""
# this is a shortcut accessor to both .loc and .iloc
# that provide the equivalent access of .at and .iat
# a) avoid getting things via sections and (to minimize dtype changes)
# b) provide a performant path
if len(key) != self.ndim:
return False
for i, k in enumerate(key):
if not is_scalar(k):
return False
ax = self.obj.axes[i]
if isinstance(ax, ABCMultiIndex):
return False
if isinstance(k, str) and ax._supports_partial_string_indexing:
# partial string indexing, df.loc['2000', 'A']
# should not be considered scalar
return False
if not ax.is_unique:
return False
return True
def _get_partial_string_timestamp_match_key(self, key, labels):
"""
Translate any partial string timestamp matches in key, returning the
new key.
(GH 10331)
"""
if isinstance(labels, ABCMultiIndex):
if (
isinstance(key, str)
and labels.levels[0]._supports_partial_string_indexing
):
# Convert key '2016-01-01' to
# ('2016-01-01'[, slice(None, None, None)]+)
key = tuple([key] + [slice(None)] * (len(labels.levels) - 1))
if isinstance(key, tuple):
# Convert (..., '2016-01-01', ...) in tuple to
# (..., slice('2016-01-01', '2016-01-01', None), ...)
new_key = []
for i, component in enumerate(key):
if (
isinstance(component, str)
and labels.levels[i]._supports_partial_string_indexing
):
new_key.append(slice(component, component, None))
else:
new_key.append(component)
key = tuple(new_key)
return key
def _getitem_axis(self, key, axis: int):
key = item_from_zerodim(key)
if is_iterator(key):
key = list(key)
labels = self.obj._get_axis(axis)
key = self._get_partial_string_timestamp_match_key(key, labels)
if isinstance(key, slice):
self._validate_key(key, axis)
return self._get_slice_axis(key, axis=axis)
elif com.is_bool_indexer(key):
return self._getbool_axis(key, axis=axis)
elif is_list_like_indexer(key):
# convert various list-like indexers
# to a list of keys
# we will use the *values* of the object
# and NOT the index if its a PandasObject
if isinstance(labels, ABCMultiIndex):
if isinstance(key, (ABCSeries, np.ndarray)) and key.ndim <= 1:
# Series, or 0,1 ndim ndarray
# GH 14730
key = list(key)
elif isinstance(key, ABCDataFrame):
# GH 15438
raise NotImplementedError(
"Indexing a MultiIndex with a "
"DataFrame key is not "
"implemented"
)
elif hasattr(key, "ndim") and key.ndim > 1:
raise NotImplementedError(
"Indexing a MultiIndex with a "
"multidimensional key is not "
"implemented"
)
if (
not isinstance(key, tuple)
and len(key)
and not isinstance(key[0], tuple)
):
key = tuple([key])
# an iterable multi-selection
if not (isinstance(key, tuple) and isinstance(labels, ABCMultiIndex)):
if hasattr(key, "ndim") and key.ndim > 1:
raise ValueError("Cannot index with multidimensional key")
return self._getitem_iterable(key, axis=axis)
# nested tuple slicing
if is_nested_tuple(key, labels):
locs = labels.get_locs(key)
indexer = [slice(None)] * self.ndim
indexer[axis] = locs
return self.obj.iloc[tuple(indexer)]
# fall thru to straight lookup
self._validate_key(key, axis)
return self._get_label(key, axis=axis)
def _get_slice_axis(self, slice_obj: slice, axis: int):
"""
This is pretty simple as we just have to deal with labels.
"""
# caller is responsible for ensuring non-None axis
obj = self.obj
if not need_slice(slice_obj):
return obj.copy(deep=False)
labels = obj._get_axis(axis)
indexer = labels.slice_indexer(
slice_obj.start, slice_obj.stop, slice_obj.step, kind=self.name
)
if isinstance(indexer, slice):
return self._slice(indexer, axis=axis, kind="iloc")
else:
# DatetimeIndex overrides Index.slice_indexer and may
# return a DatetimeIndex instead of a slice object.
return self.obj.take(indexer, axis=axis)
@Appender(IndexingMixin.iloc.__doc__)
class _iLocIndexer(_LocationIndexer):
_valid_types = (
"integer, integer slice (START point is INCLUDED, END "
"point is EXCLUDED), listlike of integers, boolean array"
)
_takeable = True
def _validate_key(self, key, axis: int):
if com.is_bool_indexer(key):
if hasattr(key, "index") and isinstance(key.index, Index):
if key.index.inferred_type == "integer":
raise NotImplementedError(
"iLocation based boolean "
"indexing on an integer type "
"is not available"
)
raise ValueError(
"iLocation based boolean indexing cannot use "
"an indexable as a mask"
)
return
if isinstance(key, slice):
return
elif is_integer(key):
self._validate_integer(key, axis)
elif isinstance(key, tuple):
# a tuple should already have been caught by this point
# so don't treat a tuple as a valid indexer
raise IndexingError("Too many indexers")
elif is_list_like_indexer(key):
arr = np.array(key)
len_axis = len(self.obj._get_axis(axis))
# check that the key has a numeric dtype
if not is_numeric_dtype(arr.dtype):
raise IndexError(f".iloc requires numeric indexers, got {arr}")
# check that the key does not exceed the maximum size of the index
if len(arr) and (arr.max() >= len_axis or arr.min() < -len_axis):
raise IndexError("positional indexers are out-of-bounds")
else:
raise ValueError(f"Can only index by location with a [{self._valid_types}]")
def _has_valid_setitem_indexer(self, indexer):
self._has_valid_positional_setitem_indexer(indexer)
def _is_scalar_access(self, key: Tuple) -> bool:
"""
Returns
-------
bool
"""
# this is a shortcut accessor to both .loc and .iloc
# that provide the equivalent access of .at and .iat
# a) avoid getting things via sections and (to minimize dtype changes)
# b) provide a performant path
if len(key) != self.ndim:
return False
for i, k in enumerate(key):
if not is_integer(k):
return False
ax = self.obj.axes[i]
if not ax.is_unique:
return False
return True
def _validate_integer(self, key: int, axis: int) -> None:
"""
Check that 'key' is a valid position in the desired axis.
Parameters
----------
key : int
Requested position.
axis : int
Desired axis.
Raises
------
IndexError
If 'key' is not a valid position in axis 'axis'.
"""
len_axis = len(self.obj._get_axis(axis))
if key >= len_axis or key < -len_axis:
raise IndexError("single positional indexer is out-of-bounds")
def _getitem_tuple(self, tup: Tuple):
self._has_valid_tuple(tup)
try:
return self._getitem_lowerdim(tup)
except IndexingError:
pass
retval = self.obj
axis = 0
for i, key in enumerate(tup):
if com.is_null_slice(key):
axis += 1
continue
retval = getattr(retval, self.name)._getitem_axis(key, axis=axis)
# if the dim was reduced, then pass a lower-dim the next time
if retval.ndim < self.ndim:
# TODO: this is never reached in tests; can we confirm that
# it is impossible?
axis -= 1
# try to get for the next axis
axis += 1
return retval
def _get_list_axis(self, key, axis: int):
"""
Return Series values by list or array of integers.
Parameters
----------
key : list-like positional indexer
axis : int
Returns
-------
Series object
Notes
-----
`axis` can only be zero.
"""
try:
return self.obj._take_with_is_copy(key, axis=axis)
except IndexError:
# re-raise with different error message
raise IndexError("positional indexers are out-of-bounds")
def _getitem_axis(self, key, axis: int):
if isinstance(key, slice):
return self._get_slice_axis(key, axis=axis)
if isinstance(key, list):
key = np.asarray(key)
if com.is_bool_indexer(key):
self._validate_key(key, axis)
return self._getbool_axis(key, axis=axis)
# a list of integers
elif is_list_like_indexer(key):
return self._get_list_axis(key, axis=axis)
# a single integer
else:
key = item_from_zerodim(key)
if not is_integer(key):
raise TypeError("Cannot index by location index with a non-integer key")
# validate the location
self._validate_integer(key, axis)
return self._get_loc(key, axis=axis)
def _get_slice_axis(self, slice_obj: slice, axis: int):
# caller is responsible for ensuring non-None axis
obj = self.obj
if not need_slice(slice_obj):
return obj.copy(deep=False)
indexer = self._convert_slice_indexer(slice_obj, axis)
return self._slice(indexer, axis=axis, kind="iloc")
def _convert_to_indexer(self, key, axis: int):
"""
Much simpler as we only have to deal with our valid types.
"""
# make need to convert a float key
if isinstance(key, slice):
return self._convert_slice_indexer(key, axis)
elif is_float(key):
return self._convert_scalar_indexer(key, axis)
try:
self._validate_key(key, axis)
return key
except ValueError:
raise ValueError(f"Can only index by location with a [{self._valid_types}]")
class _ScalarAccessIndexer(_NDFrameIndexerBase):
"""
Access scalars quickly.
"""
def _convert_key(self, key, is_setter: bool = False):
raise AbstractMethodError(self)
def __getitem__(self, key):
if not isinstance(key, tuple):
# we could have a convertible item here (e.g. Timestamp)
if not is_list_like_indexer(key):
key = tuple([key])
else:
raise ValueError("Invalid call for scalar access (getting)!")
key = self._convert_key(key)
return self.obj._get_value(*key, takeable=self._takeable)
def __setitem__(self, key, value):
if isinstance(key, tuple):
key = tuple(com.apply_if_callable(x, self.obj) for x in key)
else:
# scalar callable may return tuple
key = com.apply_if_callable(key, self.obj)
if not isinstance(key, tuple):
key = _tuplify(self.ndim, key)
if len(key) != self.ndim:
raise ValueError("Not enough indexers for scalar access (setting)!")
key = list(self._convert_key(key, is_setter=True))
self.obj._set_value(*key, value=value, takeable=self._takeable)
@Appender(IndexingMixin.at.__doc__)
class _AtIndexer(_ScalarAccessIndexer):
_takeable = False
def _convert_key(self, key, is_setter: bool = False):
"""
Require they keys to be the same type as the index. (so we don't
fallback)
"""
# allow arbitrary setting
if is_setter:
return list(key)
for ax, i in zip(self.obj.axes, key):
if ax.is_integer():
if not is_integer(i):
raise ValueError(
"At based indexing on an integer index "
"can only have integer indexers"
)
else:
if is_integer(i) and not (ax.holds_integer() or ax.is_floating()):
raise ValueError(
"At based indexing on an non-integer "
"index can only have non-integer "
"indexers"
)
return key
@Appender(IndexingMixin.iat.__doc__)
class _iAtIndexer(_ScalarAccessIndexer):
_takeable = True
def _convert_key(self, key, is_setter: bool = False):
"""
Require integer args. (and convert to label arguments)
"""
for a, i in zip(self.obj.axes, key):
if not is_integer(i):
raise ValueError("iAt based indexing can only have integer indexers")
return key
def _tuplify(ndim: int, loc: Hashable) -> Tuple[Union[Hashable, slice], ...]:
"""
Given an indexer for the first dimension, create an equivalent tuple
for indexing over all dimensions.
Parameters
----------
ndim : int
loc : object
Returns
-------
tuple
"""
_tup: List[Union[Hashable, slice]]
_tup = [slice(None, None) for _ in range(ndim)]
_tup[0] = loc
return tuple(_tup)
def convert_to_index_sliceable(obj, key):
"""
If we are index sliceable, then return my slicer, otherwise return None.
"""
idx = obj.index
if isinstance(key, slice):
return idx._convert_slice_indexer(key, kind="getitem")
elif isinstance(key, str):
# we are an actual column
if key in obj._data.items:
return None
# We might have a datetimelike string that we can translate to a
# slice here via partial string indexing
if idx._supports_partial_string_indexing:
try:
return idx._get_string_slice(key)
except (KeyError, ValueError, NotImplementedError):
return None
return None
def check_bool_indexer(index: Index, key) -> np.ndarray:
"""
Check if key is a valid boolean indexer for an object with such index and
perform reindexing or conversion if needed.
This function assumes that is_bool_indexer(key) == True.
Parameters
----------
index : Index
Index of the object on which the indexing is done.
key : list-like
Boolean indexer to check.
Returns
-------
np.array
Resulting key.
Raises
------
IndexError
If the key does not have the same length as index.
IndexingError
If the index of the key is unalignable to index.
"""
result = key
if isinstance(key, ABCSeries) and not key.index.equals(index):
result = result.reindex(index)
mask = isna(result._values)
if mask.any():
raise IndexingError(
"Unalignable boolean Series provided as "
"indexer (index of the boolean Series and of "
"the indexed object do not match)."
)
result = result.astype(bool)._values
else:
# key might be sparse / object-dtype bool, check_array_indexer needs bool array
result = np.asarray(result, dtype=bool)
result = check_array_indexer(index, result)
return result
def convert_missing_indexer(indexer):
"""
Reverse convert a missing indexer, which is a dict
return the scalar indexer and a boolean indicating if we converted
"""
if isinstance(indexer, dict):
# a missing key (but not a tuple indexer)
indexer = indexer["key"]
if isinstance(indexer, bool):
raise KeyError("cannot use a single bool to index into setitem")
return indexer, True
return indexer, False
def convert_from_missing_indexer_tuple(indexer, axes):
"""
Create a filtered indexer that doesn't have any missing indexers.
"""
def get_indexer(_i, _idx):
return axes[_i].get_loc(_idx["key"]) if isinstance(_idx, dict) else _idx
return tuple(get_indexer(_i, _idx) for _i, _idx in enumerate(indexer))
def maybe_convert_ix(*args):
"""
We likely want to take the cross-product.
"""
ixify = True
for arg in args:
if not isinstance(arg, (np.ndarray, list, ABCSeries, Index)):
ixify = False
if ixify:
return np.ix_(*args)
else:
return args
def is_nested_tuple(tup, labels) -> bool:
"""
Returns
-------
bool
"""
# check for a compatible nested tuple and multiindexes among the axes
if not isinstance(tup, tuple):
return False
for i, k in enumerate(tup):
if is_list_like(k) or isinstance(k, slice):
return isinstance(labels, ABCMultiIndex)
return False
def is_label_like(key) -> bool:
"""
Returns
-------
bool
"""
# select a label or row
return not isinstance(key, slice) and not is_list_like_indexer(key)
def need_slice(obj) -> bool:
"""
Returns
-------
bool
"""
return (
obj.start is not None
or obj.stop is not None
or (obj.step is not None and obj.step != 1)
)
def _non_reducing_slice(slice_):
"""
Ensurse that a slice doesn't reduce to a Series or Scalar.
Any user-paseed `subset` should have this called on it
to make sure we're always working with DataFrames.
"""
# default to column slice, like DataFrame
# ['A', 'B'] -> IndexSlices[:, ['A', 'B']]
kinds = (ABCSeries, np.ndarray, Index, list, str)
if isinstance(slice_, kinds):
slice_ = IndexSlice[:, slice_]
def pred(part) -> bool:
"""
Returns
-------
bool
True if slice does *not* reduce,
False if `part` is a tuple.
"""
# true when slice does *not* reduce, False when part is a tuple,
# i.e. MultiIndex slice
return (isinstance(part, slice) or is_list_like(part)) and not isinstance(
part, tuple
)
if not is_list_like(slice_):
if not isinstance(slice_, slice):
# a 1-d slice, like df.loc[1]
slice_ = [[slice_]]
else:
# slice(a, b, c)
slice_ = [slice_] # to tuplize later
else:
slice_ = [part if pred(part) else [part] for part in slice_]
return tuple(slice_)
def _maybe_numeric_slice(df, slice_, include_bool=False):
"""
Want nice defaults for background_gradient that don't break
with non-numeric data. But if slice_ is passed go with that.
"""
if slice_ is None:
dtypes = [np.number]
if include_bool:
dtypes.append(bool)
slice_ = IndexSlice[:, df.select_dtypes(include=dtypes).columns]
return slice_
def _can_do_equal_len(labels, value, plane_indexer, lplane_indexer, obj) -> bool:
"""
Returns
-------
bool
True if we have an equal len settable.
"""
if not len(labels) == 1 or not np.iterable(value) or is_scalar(plane_indexer[0]):
return False
item = labels[0]
index = obj[item].index
values_len = len(value)
# equal len list/ndarray
if len(index) == values_len:
return True
elif lplane_indexer == values_len:
return True
return False
| BugsInPy/BugsInPy/temp/projects/pandas/bug-69-fixed/pandas/pandas/core/indexing.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-69-buggy/pandas/pandas/core/indexing.py |
pandas-bug-121 | from datetime import datetime, timedelta
import functools
import inspect
import re
from typing import Any, List
import warnings
import numpy as np
from pandas._libs import NaT, algos as libalgos, lib, tslib, writers
from pandas._libs.index import convert_scalar
import pandas._libs.internals as libinternals
from pandas._libs.tslibs import Timedelta, conversion
from pandas._libs.tslibs.timezones import tz_compare
from pandas.util._validators import validate_bool_kwarg
from pandas.core.dtypes.cast import (
astype_nansafe,
find_common_type,
infer_dtype_from,
infer_dtype_from_scalar,
maybe_downcast_numeric,
maybe_downcast_to_dtype,
maybe_infer_dtype_type,
maybe_promote,
maybe_upcast,
soft_convert_objects,
)
from pandas.core.dtypes.common import (
_NS_DTYPE,
_TD_DTYPE,
ensure_platform_int,
is_bool_dtype,
is_categorical,
is_categorical_dtype,
is_datetime64_dtype,
is_datetime64tz_dtype,
is_dtype_equal,
is_extension_array_dtype,
is_float_dtype,
is_integer,
is_integer_dtype,
is_interval_dtype,
is_list_like,
is_object_dtype,
is_period_dtype,
is_re,
is_re_compilable,
is_sparse,
is_timedelta64_dtype,
pandas_dtype,
)
from pandas.core.dtypes.concat import concat_categorical, concat_datetime
from pandas.core.dtypes.dtypes import CategoricalDtype, ExtensionDtype
from pandas.core.dtypes.generic import (
ABCDataFrame,
ABCExtensionArray,
ABCPandasArray,
ABCSeries,
)
from pandas.core.dtypes.missing import (
_isna_compat,
array_equivalent,
is_valid_nat_for_dtype,
isna,
)
import pandas.core.algorithms as algos
from pandas.core.arrays import Categorical, DatetimeArray, PandasDtype, TimedeltaArray
from pandas.core.base import PandasObject
import pandas.core.common as com
from pandas.core.construction import extract_array
from pandas.core.indexers import (
check_setitem_lengths,
is_empty_indexer,
is_scalar_indexer,
)
import pandas.core.missing as missing
from pandas.core.nanops import nanpercentile
from pandas.io.formats.printing import pprint_thing
class Block(PandasObject):
"""
Canonical n-dimensional unit of homogeneous dtype contained in a pandas
data structure
Index-ignorant; let the container take care of that
"""
__slots__ = ["_mgr_locs", "values", "ndim"]
is_numeric = False
is_float = False
is_integer = False
is_complex = False
is_datetime = False
is_datetimetz = False
is_timedelta = False
is_bool = False
is_object = False
is_categorical = False
is_extension = False
_can_hold_na = False
_can_consolidate = True
_verify_integrity = True
_validate_ndim = True
_ftype = "dense"
_concatenator = staticmethod(np.concatenate)
def __init__(self, values, placement, ndim=None):
self.ndim = self._check_ndim(values, ndim)
self.mgr_locs = placement
self.values = values
if self._validate_ndim and self.ndim and len(self.mgr_locs) != len(self.values):
raise ValueError(
"Wrong number of items passed {val}, placement implies "
"{mgr}".format(val=len(self.values), mgr=len(self.mgr_locs))
)
def _check_ndim(self, values, ndim):
"""
ndim inference and validation.
Infers ndim from 'values' if not provided to __init__.
Validates that values.ndim and ndim are consistent if and only if
the class variable '_validate_ndim' is True.
Parameters
----------
values : array-like
ndim : int or None
Returns
-------
ndim : int
Raises
------
ValueError : the number of dimensions do not match
"""
if ndim is None:
ndim = values.ndim
if self._validate_ndim and values.ndim != ndim:
msg = "Wrong number of dimensions. values.ndim != ndim [{} != {}]"
raise ValueError(msg.format(values.ndim, ndim))
return ndim
@property
def _holder(self):
"""The array-like that can hold the underlying values.
None for 'Block', overridden by subclasses that don't
use an ndarray.
"""
return None
@property
def _consolidate_key(self):
return (self._can_consolidate, self.dtype.name)
@property
def _is_single_block(self):
return self.ndim == 1
@property
def is_view(self):
""" return a boolean if I am possibly a view """
return self.values.base is not None
@property
def is_datelike(self):
""" return True if I am a non-datelike """
return self.is_datetime or self.is_timedelta
def is_categorical_astype(self, dtype):
"""
validate that we have a astypeable to categorical,
returns a boolean if we are a categorical
"""
if dtype is Categorical or dtype is CategoricalDtype:
# this is a pd.Categorical, but is not
# a valid type for astypeing
raise TypeError("invalid type {0} for astype".format(dtype))
elif is_categorical_dtype(dtype):
return True
return False
def external_values(self, dtype=None):
""" return an outside world format, currently just the ndarray """
return self.values
def internal_values(self, dtype=None):
""" return an internal format, currently just the ndarray
this should be the pure internal API format
"""
return self.values
def get_values(self, dtype=None):
"""
return an internal format, currently just the ndarray
this is often overridden to handle to_dense like operations
"""
if is_object_dtype(dtype):
return self.values.astype(object)
return self.values
def get_block_values(self, dtype=None):
"""
This is used in the JSON C code
"""
return self.get_values(dtype=dtype)
def to_dense(self):
return self.values.view()
@property
def fill_value(self):
return np.nan
@property
def mgr_locs(self):
return self._mgr_locs
@mgr_locs.setter
def mgr_locs(self, new_mgr_locs):
if not isinstance(new_mgr_locs, libinternals.BlockPlacement):
new_mgr_locs = libinternals.BlockPlacement(new_mgr_locs)
self._mgr_locs = new_mgr_locs
@property
def array_dtype(self):
""" the dtype to return if I want to construct this block as an
array
"""
return self.dtype
def make_block(self, values, placement=None):
"""
Create a new block, with type inference propagate any values that are
not specified
"""
if placement is None:
placement = self.mgr_locs
return make_block(values, placement=placement, ndim=self.ndim)
def make_block_same_class(self, values, placement=None, ndim=None, dtype=None):
""" Wrap given values in a block of same type as self. """
if dtype is not None:
# issue 19431 fastparquet is passing this
warnings.warn(
"dtype argument is deprecated, will be removed in a future release.",
FutureWarning,
)
if placement is None:
placement = self.mgr_locs
if ndim is None:
ndim = self.ndim
return make_block(
values, placement=placement, ndim=ndim, klass=self.__class__, dtype=dtype
)
def __repr__(self) -> str:
# don't want to print out all of the items here
name = pprint_thing(self.__class__.__name__)
if self._is_single_block:
result = "{name}: {len} dtype: {dtype}".format(
name=name, len=len(self), dtype=self.dtype
)
else:
shape = " x ".join(pprint_thing(s) for s in self.shape)
result = "{name}: {index}, {shape}, dtype: {dtype}".format(
name=name,
index=pprint_thing(self.mgr_locs.indexer),
shape=shape,
dtype=self.dtype,
)
return result
def __len__(self) -> int:
return len(self.values)
def __getstate__(self):
return self.mgr_locs.indexer, self.values
def __setstate__(self, state):
self.mgr_locs = libinternals.BlockPlacement(state[0])
self.values = state[1]
self.ndim = self.values.ndim
def _slice(self, slicer):
""" return a slice of my values """
return self.values[slicer]
def getitem_block(self, slicer, new_mgr_locs=None):
"""
Perform __getitem__-like, return result as block.
As of now, only supports slices that preserve dimensionality.
"""
if new_mgr_locs is None:
if isinstance(slicer, tuple):
axis0_slicer = slicer[0]
else:
axis0_slicer = slicer
new_mgr_locs = self.mgr_locs[axis0_slicer]
new_values = self._slice(slicer)
if self._validate_ndim and new_values.ndim != self.ndim:
raise ValueError("Only same dim slicing is allowed")
return self.make_block_same_class(new_values, new_mgr_locs)
@property
def shape(self):
return self.values.shape
@property
def dtype(self):
return self.values.dtype
@property
def ftype(self):
if getattr(self.values, "_pandas_ftype", False):
dtype = self.dtype.subtype
else:
dtype = self.dtype
return "{dtype}:{ftype}".format(dtype=dtype, ftype=self._ftype)
def merge(self, other):
return _merge_blocks([self, other])
def concat_same_type(self, to_concat, placement=None):
"""
Concatenate list of single blocks of the same type.
"""
values = self._concatenator(
[blk.values for blk in to_concat], axis=self.ndim - 1
)
return self.make_block_same_class(
values, placement=placement or slice(0, len(values), 1)
)
def iget(self, i):
return self.values[i]
def set(self, locs, values):
"""
Modify Block in-place with new item value
Returns
-------
None
"""
self.values[locs] = values
def delete(self, loc):
"""
Delete given loc(-s) from block in-place.
"""
self.values = np.delete(self.values, loc, 0)
self.mgr_locs = self.mgr_locs.delete(loc)
def apply(self, func, **kwargs):
""" apply the function to my values; return a block if we are not
one
"""
with np.errstate(all="ignore"):
result = func(self.values, **kwargs)
if not isinstance(result, Block):
result = self.make_block(values=_block_shape(result, ndim=self.ndim))
return result
def fillna(self, value, limit=None, inplace=False, downcast=None):
""" fillna on the block with the value. If we fail, then convert to
ObjectBlock and try again
"""
inplace = validate_bool_kwarg(inplace, "inplace")
mask = isna(self.values)
if limit is not None:
limit = libalgos._validate_limit(None, limit=limit)
mask[mask.cumsum(self.ndim - 1) > limit] = False
if not self._can_hold_na:
if inplace:
return self
else:
return self.copy()
if self._can_hold_element(value):
# equivalent: _try_coerce_args(value) would not raise
blocks = self.putmask(mask, value, inplace=inplace)
return self._maybe_downcast(blocks, downcast)
# we can't process the value, but nothing to do
if not mask.any():
return self if inplace else self.copy()
# operate column-by-column
def f(mask, val, idx):
block = self.coerce_to_target_dtype(value)
# slice out our block
if idx is not None:
# i.e. self.ndim == 2
block = block.getitem_block(slice(idx, idx + 1))
return block.fillna(value, limit=limit, inplace=inplace, downcast=None)
return self.split_and_operate(None, f, inplace)
def split_and_operate(self, mask, f, inplace: bool):
"""
split the block per-column, and apply the callable f
per-column, return a new block for each. Handle
masking which will not change a block unless needed.
Parameters
----------
mask : 2-d boolean mask
f : callable accepting (1d-mask, 1d values, indexer)
inplace : boolean
Returns
-------
list of blocks
"""
if mask is None:
mask = np.broadcast_to(True, shape=self.shape)
new_values = self.values
def make_a_block(nv, ref_loc):
if isinstance(nv, list):
assert len(nv) == 1, nv
assert isinstance(nv[0], Block)
block = nv[0]
else:
# Put back the dimension that was taken from it and make
# a block out of the result.
nv = _block_shape(nv, ndim=self.ndim)
block = self.make_block(values=nv, placement=ref_loc)
return block
# ndim == 1
if self.ndim == 1:
if mask.any():
nv = f(mask, new_values, None)
else:
nv = new_values if inplace else new_values.copy()
block = make_a_block(nv, self.mgr_locs)
return [block]
# ndim > 1
new_blocks = []
for i, ref_loc in enumerate(self.mgr_locs):
m = mask[i]
v = new_values[i]
# need a new block
if m.any():
nv = f(m, v, i)
else:
nv = v if inplace else v.copy()
block = make_a_block(nv, [ref_loc])
new_blocks.append(block)
return new_blocks
def _maybe_downcast(self, blocks: List["Block"], downcast=None) -> List["Block"]:
# no need to downcast our float
# unless indicated
if downcast is None and (
self.is_float or self.is_timedelta or self.is_datetime
):
return blocks
return _extend_blocks([b.downcast(downcast) for b in blocks])
def downcast(self, dtypes=None):
""" try to downcast each item to the dict of dtypes if present """
# turn it off completely
if dtypes is False:
return self
values = self.values
# single block handling
if self._is_single_block:
# try to cast all non-floats here
if dtypes is None:
dtypes = "infer"
nv = maybe_downcast_to_dtype(values, dtypes)
return self.make_block(nv)
# ndim > 1
if dtypes is None:
return self
if not (dtypes == "infer" or isinstance(dtypes, dict)):
raise ValueError(
"downcast must have a dictionary or 'infer' as its argument"
)
elif dtypes != "infer":
raise AssertionError("dtypes as dict is not supported yet")
# operate column-by-column
# this is expensive as it splits the blocks items-by-item
def f(mask, val, idx):
val = maybe_downcast_to_dtype(val, dtype="infer")
return val
return self.split_and_operate(None, f, False)
def astype(self, dtype, copy=False, errors="raise", **kwargs):
return self._astype(dtype, copy=copy, errors=errors, **kwargs)
def _astype(self, dtype, copy=False, errors="raise", **kwargs):
"""Coerce to the new type
Parameters
----------
dtype : str, dtype convertible
copy : boolean, default False
copy if indicated
errors : str, {'raise', 'ignore'}, default 'ignore'
- ``raise`` : allow exceptions to be raised
- ``ignore`` : suppress exceptions. On error return original object
Returns
-------
Block
"""
errors_legal_values = ("raise", "ignore")
if errors not in errors_legal_values:
invalid_arg = (
"Expected value of kwarg 'errors' to be one of {}. "
"Supplied value is '{}'".format(list(errors_legal_values), errors)
)
raise ValueError(invalid_arg)
if inspect.isclass(dtype) and issubclass(dtype, ExtensionDtype):
msg = (
"Expected an instance of {}, but got the class instead. "
"Try instantiating 'dtype'.".format(dtype.__name__)
)
raise TypeError(msg)
# may need to convert to categorical
if self.is_categorical_astype(dtype):
if is_categorical_dtype(self.values):
# GH 10696/18593: update an existing categorical efficiently
return self.make_block(self.values.astype(dtype, copy=copy))
return self.make_block(Categorical(self.values, dtype=dtype))
dtype = pandas_dtype(dtype)
# astype processing
if is_dtype_equal(self.dtype, dtype):
if copy:
return self.copy()
return self
# force the copy here
if self.is_extension:
# TODO: Should we try/except this astype?
values = self.values.astype(dtype)
else:
if issubclass(dtype.type, str):
# use native type formatting for datetime/tz/timedelta
if self.is_datelike:
values = self.to_native_types()
# astype formatting
else:
values = self.get_values()
else:
values = self.get_values(dtype=dtype)
# _astype_nansafe works fine with 1-d only
vals1d = values.ravel()
try:
values = astype_nansafe(vals1d, dtype, copy=True)
except (ValueError, TypeError):
# e.g. astype_nansafe can fail on object-dtype of strings
# trying to convert to float
if errors == "raise":
raise
newb = self.copy() if copy else self
return newb
# TODO(extension)
# should we make this attribute?
if isinstance(values, np.ndarray):
values = values.reshape(self.shape)
newb = make_block(values, placement=self.mgr_locs, ndim=self.ndim)
if newb.is_numeric and self.is_numeric:
if newb.shape != self.shape:
raise TypeError(
"cannot set astype for copy = [{copy}] for dtype "
"({dtype} [{shape}]) to different shape "
"({newb_dtype} [{newb_shape}])".format(
copy=copy,
dtype=self.dtype.name,
shape=self.shape,
newb_dtype=newb.dtype.name,
newb_shape=newb.shape,
)
)
return newb
def convert(
self,
copy: bool = True,
datetime: bool = True,
numeric: bool = True,
timedelta: bool = True,
coerce: bool = False,
):
""" attempt to coerce any object types to better types return a copy
of the block (if copy = True) by definition we are not an ObjectBlock
here!
"""
return self.copy() if copy else self
def _can_hold_element(self, element: Any) -> bool:
""" require the same dtype as ourselves """
dtype = self.values.dtype.type
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return issubclass(tipo.type, dtype)
return isinstance(element, dtype)
def to_native_types(self, slicer=None, na_rep="nan", quoting=None, **kwargs):
""" convert to our native types format, slicing if desired """
values = self.get_values()
if slicer is not None:
values = values[:, slicer]
mask = isna(values)
if not self.is_object and not quoting:
itemsize = writers.word_len(na_rep)
values = values.astype("<U{size}".format(size=itemsize))
else:
values = np.array(values, dtype="object")
values[mask] = na_rep
return values
# block actions #
def copy(self, deep=True):
""" copy constructor """
values = self.values
if deep:
values = values.copy()
return self.make_block_same_class(values, ndim=self.ndim)
def replace(
self, to_replace, value, inplace=False, filter=None, regex=False, convert=True
):
"""replace the to_replace value with value, possible to create new
blocks here this is just a call to putmask. regex is not used here.
It is used in ObjectBlocks. It is here for API compatibility.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
original_to_replace = to_replace
# If we cannot replace with own dtype, convert to ObjectBlock and
# retry
if not self._can_hold_element(to_replace):
if not isinstance(to_replace, list):
if inplace:
return [self]
return [self.copy()]
to_replace = [x for x in to_replace if self._can_hold_element(x)]
if not len(to_replace):
# GH#28084 avoid costly checks since we can infer
# that there is nothing to replace in this block
if inplace:
return [self]
return [self.copy()]
if len(to_replace) == 1:
# _can_hold_element checks have reduced this back to the
# scalar case and we can avoid a costly object cast
return self.replace(
to_replace[0],
value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
# GH 22083, TypeError or ValueError occurred within error handling
# causes infinite loop. Cast and retry only if not objectblock.
if is_object_dtype(self):
raise AssertionError
# try again with a compatible block
block = self.astype(object)
return block.replace(
to_replace=to_replace,
value=value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
values = self.values
if lib.is_scalar(to_replace) and isinstance(values, np.ndarray):
# The only non-DatetimeLike class that also has a non-trivial
# try_coerce_args is ObjectBlock, but that overrides replace,
# so does not get here.
to_replace = convert_scalar(values, to_replace)
mask = missing.mask_missing(values, to_replace)
if filter is not None:
filtered_out = ~self.mgr_locs.isin(filter)
mask[filtered_out.nonzero()[0]] = False
if not mask.any():
if inplace:
return [self]
return [self.copy()]
try:
blocks = self.putmask(mask, value, inplace=inplace)
# Note: it is _not_ the case that self._can_hold_element(value)
# is always true at this point. In particular, that can fail
# for:
# "2u" with bool-dtype, float-dtype
# 0.5 with int64-dtype
# np.nan with int64-dtype
except (TypeError, ValueError):
# GH 22083, TypeError or ValueError occurred within error handling
# causes infinite loop. Cast and retry only if not objectblock.
if is_object_dtype(self):
raise
assert not self._can_hold_element(value), value
# try again with a compatible block
block = self.astype(object)
return block.replace(
to_replace=original_to_replace,
value=value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
if convert:
blocks = [b.convert(numeric=False, copy=not inplace) for b in blocks]
return blocks
def _replace_single(self, *args, **kwargs):
""" no-op on a non-ObjectBlock """
return self if kwargs["inplace"] else self.copy()
def setitem(self, indexer, value):
"""
Set the value inplace, returning a a maybe different typed block.
Parameters
----------
indexer : tuple, list-like, array-like, slice
The subset of self.values to set
value : object
The value being set
Returns
-------
Block
Notes
-----
`indexer` is a direct slice/positional indexer. `value` must
be a compatible shape.
"""
transpose = self.ndim == 2
# coerce None values, if appropriate
if value is None:
if self.is_numeric:
value = np.nan
# coerce if block dtype can store value
values = self.values
if self._can_hold_element(value):
# We only get here for non-Extension Blocks, so _try_coerce_args
# is only relevant for DatetimeBlock and TimedeltaBlock
if lib.is_scalar(value):
value = convert_scalar(values, value)
else:
# current dtype cannot store value, coerce to common dtype
find_dtype = False
if hasattr(value, "dtype"):
dtype = value.dtype
find_dtype = True
elif lib.is_scalar(value) and not isna(value):
dtype, _ = infer_dtype_from_scalar(value, pandas_dtype=True)
find_dtype = True
if find_dtype:
dtype = find_common_type([values.dtype, dtype])
if not is_dtype_equal(self.dtype, dtype):
b = self.astype(dtype)
return b.setitem(indexer, value)
# value must be storeable at this moment
if is_extension_array_dtype(getattr(value, "dtype", None)):
# We need to be careful not to allow through strings that
# can be parsed to EADtypes
arr_value = value
else:
arr_value = np.array(value)
# cast the values to a type that can hold nan (if necessary)
if not self._can_hold_element(value):
dtype, _ = maybe_promote(arr_value.dtype)
values = values.astype(dtype)
if transpose:
values = values.T
# length checking
check_setitem_lengths(indexer, value, values)
if is_empty_indexer(indexer, arr_value):
# GH#8669 empty indexers
pass
elif is_scalar_indexer(indexer, arr_value):
# setting a single element for each dim and with a rhs that could
# be e.g. a list; see GH#6043
values[indexer] = value
# if we are an exact match (ex-broadcasting),
# then use the resultant dtype
elif (
len(arr_value.shape)
and arr_value.shape[0] == values.shape[0]
and arr_value.size == values.size
):
values[indexer] = value
try:
values = values.astype(arr_value.dtype)
except ValueError:
pass
# set
else:
values[indexer] = value
if transpose:
values = values.T
block = self.make_block(values)
return block
def putmask(self, mask, new, align=True, inplace=False, axis=0, transpose=False):
""" putmask the data to the block; it is possible that we may create a
new dtype of block
return the resulting block(s)
Parameters
----------
mask : the condition to respect
new : a ndarray/object
align : boolean, perform alignment on other/cond, default is True
inplace : perform inplace modification, default is False
axis : int
transpose : boolean
Set to True if self is stored with axes reversed
Returns
-------
a list of new blocks, the result of the putmask
"""
new_values = self.values if inplace else self.values.copy()
new = getattr(new, "values", new)
mask = getattr(mask, "values", mask)
# if we are passed a scalar None, convert it here
if not is_list_like(new) and isna(new) and not self.is_object:
# FIXME: make sure we have compatible NA
new = self.fill_value
if self._can_hold_element(new):
# We only get here for non-Extension Blocks, so _try_coerce_args
# is only relevant for DatetimeBlock and TimedeltaBlock
if lib.is_scalar(new):
new = convert_scalar(new_values, new)
if transpose:
new_values = new_values.T
# If the default repeat behavior in np.putmask would go in the
# wrong direction, then explicitly repeat and reshape new instead
if getattr(new, "ndim", 0) >= 1:
if self.ndim - 1 == new.ndim and axis == 1:
new = np.repeat(new, new_values.shape[-1]).reshape(self.shape)
new = new.astype(new_values.dtype)
# we require exact matches between the len of the
# values we are setting (or is compat). np.putmask
# doesn't check this and will simply truncate / pad
# the output, but we want sane error messages
#
# TODO: this prob needs some better checking
# for 2D cases
if (
is_list_like(new)
and np.any(mask[mask])
and getattr(new, "ndim", 1) == 1
):
if not (
mask.shape[-1] == len(new)
or mask[mask].shape[-1] == len(new)
or len(new) == 1
):
raise ValueError("cannot assign mismatch length to masked array")
np.putmask(new_values, mask, new)
# maybe upcast me
elif mask.any():
if transpose:
mask = mask.T
if isinstance(new, np.ndarray):
new = new.T
axis = new_values.ndim - axis - 1
# Pseudo-broadcast
if getattr(new, "ndim", 0) >= 1:
if self.ndim - 1 == new.ndim:
new_shape = list(new.shape)
new_shape.insert(axis, 1)
new = new.reshape(tuple(new_shape))
# operate column-by-column
def f(mask, val, idx):
if idx is None:
# ndim==1 case.
n = new
else:
if isinstance(new, np.ndarray):
n = np.squeeze(new[idx % new.shape[0]])
else:
n = np.array(new)
# type of the new block
dtype, _ = maybe_promote(n.dtype)
# we need to explicitly astype here to make a copy
n = n.astype(dtype)
nv = _putmask_smart(val, mask, n)
return nv
new_blocks = self.split_and_operate(mask, f, inplace)
return new_blocks
if inplace:
return [self]
if transpose:
new_values = new_values.T
return [self.make_block(new_values)]
def coerce_to_target_dtype(self, other):
"""
coerce the current block to a dtype compat for other
we will return a block, possibly object, and not raise
we can also safely try to coerce to the same dtype
and will receive the same block
"""
# if we cannot then coerce to object
dtype, _ = infer_dtype_from(other, pandas_dtype=True)
if is_dtype_equal(self.dtype, dtype):
return self
if self.is_bool or is_object_dtype(dtype) or is_bool_dtype(dtype):
# we don't upcast to bool
return self.astype(object)
elif (self.is_float or self.is_complex) and (
is_integer_dtype(dtype) or is_float_dtype(dtype)
):
# don't coerce float/complex to int
return self
elif (
self.is_datetime
or is_datetime64_dtype(dtype)
or is_datetime64tz_dtype(dtype)
):
# not a datetime
if not (
(is_datetime64_dtype(dtype) or is_datetime64tz_dtype(dtype))
and self.is_datetime
):
return self.astype(object)
# don't upcast timezone with different timezone or no timezone
mytz = getattr(self.dtype, "tz", None)
othertz = getattr(dtype, "tz", None)
if not tz_compare(mytz, othertz):
return self.astype(object)
raise AssertionError(
"possible recursion in "
"coerce_to_target_dtype: {} {}".format(self, other)
)
elif self.is_timedelta or is_timedelta64_dtype(dtype):
# not a timedelta
if not (is_timedelta64_dtype(dtype) and self.is_timedelta):
return self.astype(object)
raise AssertionError(
"possible recursion in "
"coerce_to_target_dtype: {} {}".format(self, other)
)
try:
return self.astype(dtype)
except (ValueError, TypeError, OverflowError):
return self.astype(object)
def interpolate(
self,
method="pad",
axis=0,
index=None,
values=None,
inplace=False,
limit=None,
limit_direction="forward",
limit_area=None,
fill_value=None,
coerce=False,
downcast=None,
**kwargs,
):
inplace = validate_bool_kwarg(inplace, "inplace")
def check_int_bool(self, inplace):
# Only FloatBlocks will contain NaNs.
# timedelta subclasses IntBlock
if (self.is_bool or self.is_integer) and not self.is_timedelta:
if inplace:
return self
else:
return self.copy()
# a fill na type method
try:
m = missing.clean_fill_method(method)
except ValueError:
m = None
if m is not None:
r = check_int_bool(self, inplace)
if r is not None:
return r
return self._interpolate_with_fill(
method=m,
axis=axis,
inplace=inplace,
limit=limit,
fill_value=fill_value,
coerce=coerce,
downcast=downcast,
)
# validate the interp method
m = missing.clean_interp_method(method, **kwargs)
r = check_int_bool(self, inplace)
if r is not None:
return r
return self._interpolate(
method=m,
index=index,
values=values,
axis=axis,
limit=limit,
limit_direction=limit_direction,
limit_area=limit_area,
fill_value=fill_value,
inplace=inplace,
downcast=downcast,
**kwargs,
)
def _interpolate_with_fill(
self,
method="pad",
axis=0,
inplace=False,
limit=None,
fill_value=None,
coerce=False,
downcast=None,
):
""" fillna but using the interpolate machinery """
inplace = validate_bool_kwarg(inplace, "inplace")
# if we are coercing, then don't force the conversion
# if the block can't hold the type
if coerce:
if not self._can_hold_na:
if inplace:
return [self]
else:
return [self.copy()]
values = self.values if inplace else self.values.copy()
# We only get here for non-ExtensionBlock
fill_value = convert_scalar(self.values, fill_value)
values = missing.interpolate_2d(
values,
method=method,
axis=axis,
limit=limit,
fill_value=fill_value,
dtype=self.dtype,
)
blocks = [self.make_block_same_class(values, ndim=self.ndim)]
return self._maybe_downcast(blocks, downcast)
def _interpolate(
self,
method=None,
index=None,
values=None,
fill_value=None,
axis=0,
limit=None,
limit_direction="forward",
limit_area=None,
inplace=False,
downcast=None,
**kwargs,
):
""" interpolate using scipy wrappers """
inplace = validate_bool_kwarg(inplace, "inplace")
data = self.values if inplace else self.values.copy()
# only deal with floats
if not self.is_float:
if not self.is_integer:
return self
data = data.astype(np.float64)
if fill_value is None:
fill_value = self.fill_value
if method in ("krogh", "piecewise_polynomial", "pchip"):
if not index.is_monotonic:
raise ValueError(
"{0} interpolation requires that the "
"index be monotonic.".format(method)
)
# process 1-d slices in the axis direction
def func(x):
# process a 1-d slice, returning it
# should the axis argument be handled below in apply_along_axis?
# i.e. not an arg to missing.interpolate_1d
return missing.interpolate_1d(
index,
x,
method=method,
limit=limit,
limit_direction=limit_direction,
limit_area=limit_area,
fill_value=fill_value,
bounds_error=False,
**kwargs,
)
# interp each column independently
interp_values = np.apply_along_axis(func, axis, data)
blocks = [self.make_block_same_class(interp_values)]
return self._maybe_downcast(blocks, downcast)
def take_nd(self, indexer, axis, new_mgr_locs=None, fill_tuple=None):
"""
Take values according to indexer and return them as a block.bb
"""
# algos.take_nd dispatches for DatetimeTZBlock, CategoricalBlock
# so need to preserve types
# sparse is treated like an ndarray, but needs .get_values() shaping
values = self.values
if fill_tuple is None:
fill_value = self.fill_value
allow_fill = False
else:
fill_value = fill_tuple[0]
allow_fill = True
new_values = algos.take_nd(
values, indexer, axis=axis, allow_fill=allow_fill, fill_value=fill_value
)
# Called from three places in managers, all of which satisfy
# this assertion
assert not (axis == 0 and new_mgr_locs is None)
if new_mgr_locs is None:
new_mgr_locs = self.mgr_locs
if not is_dtype_equal(new_values.dtype, self.dtype):
return self.make_block(new_values, new_mgr_locs)
else:
return self.make_block_same_class(new_values, new_mgr_locs)
def diff(self, n: int, axis: int = 1) -> List["Block"]:
""" return block for the diff of the values """
new_values = algos.diff(self.values, n, axis=axis)
return [self.make_block(values=new_values)]
def shift(self, periods, axis=0, fill_value=None):
""" shift the block by periods, possibly upcast """
# convert integer to float if necessary. need to do a lot more than
# that, handle boolean etc also
new_values, fill_value = maybe_upcast(self.values, fill_value)
# make sure array sent to np.roll is c_contiguous
f_ordered = new_values.flags.f_contiguous
if f_ordered:
new_values = new_values.T
axis = new_values.ndim - axis - 1
if np.prod(new_values.shape):
new_values = np.roll(new_values, ensure_platform_int(periods), axis=axis)
axis_indexer = [slice(None)] * self.ndim
if periods > 0:
axis_indexer[axis] = slice(None, periods)
else:
axis_indexer[axis] = slice(periods, None)
new_values[tuple(axis_indexer)] = fill_value
# restore original order
if f_ordered:
new_values = new_values.T
return [self.make_block(new_values)]
def where(
self,
other,
cond,
align=True,
errors="raise",
try_cast: bool = False,
axis: int = 0,
) -> List["Block"]:
"""
evaluate the block; return result block(s) from the result
Parameters
----------
other : a ndarray/object
cond : the condition to respect
align : boolean, perform alignment on other/cond
errors : str, {'raise', 'ignore'}, default 'raise'
- ``raise`` : allow exceptions to be raised
- ``ignore`` : suppress exceptions. On error return original object
axis : int
Returns
-------
a new block(s), the result of the func
"""
import pandas.core.computation.expressions as expressions
assert errors in ["raise", "ignore"]
transpose = self.ndim == 2
values = self.values
orig_other = other
if transpose:
values = values.T
other = getattr(other, "_values", getattr(other, "values", other))
cond = getattr(cond, "values", cond)
# If the default broadcasting would go in the wrong direction, then
# explicitly reshape other instead
if getattr(other, "ndim", 0) >= 1:
if values.ndim - 1 == other.ndim and axis == 1:
other = other.reshape(tuple(other.shape + (1,)))
elif transpose and values.ndim == self.ndim - 1:
cond = cond.T
if not hasattr(cond, "shape"):
raise ValueError("where must have a condition that is ndarray like")
# our where function
def func(cond, values, other):
if not (
(self.is_integer or self.is_bool)
and lib.is_float(other)
and np.isnan(other)
):
# np.where will cast integer array to floats in this case
if not self._can_hold_element(other):
raise TypeError
if lib.is_scalar(other) and isinstance(values, np.ndarray):
other = convert_scalar(values, other)
fastres = expressions.where(cond, values, other)
return fastres
if cond.ravel().all():
result = values
else:
# see if we can operate on the entire block, or need item-by-item
# or if we are a single block (ndim == 1)
try:
result = func(cond, values, other)
except TypeError:
# we cannot coerce, return a compat dtype
# we are explicitly ignoring errors
block = self.coerce_to_target_dtype(other)
blocks = block.where(
orig_other,
cond,
align=align,
errors=errors,
try_cast=try_cast,
axis=axis,
)
return self._maybe_downcast(blocks, "infer")
if self._can_hold_na or self.ndim == 1:
if transpose:
result = result.T
return [self.make_block(result)]
# might need to separate out blocks
axis = cond.ndim - 1
cond = cond.swapaxes(axis, 0)
mask = np.array([cond[i].all() for i in range(cond.shape[0])], dtype=bool)
result_blocks = []
for m in [mask, ~mask]:
if m.any():
taken = result.take(m.nonzero()[0], axis=axis)
r = maybe_downcast_numeric(taken, self.dtype)
nb = self.make_block(r.T, placement=self.mgr_locs[m])
result_blocks.append(nb)
return result_blocks
def equals(self, other) -> bool:
if self.dtype != other.dtype or self.shape != other.shape:
return False
return array_equivalent(self.values, other.values)
def _unstack(self, unstacker_func, new_columns, n_rows, fill_value):
"""Return a list of unstacked blocks of self
Parameters
----------
unstacker_func : callable
Partially applied unstacker.
new_columns : Index
All columns of the unstacked BlockManager.
n_rows : int
Only used in ExtensionBlock._unstack
fill_value : int
Only used in ExtensionBlock._unstack
Returns
-------
blocks : list of Block
New blocks of unstacked values.
mask : array_like of bool
The mask of columns of `blocks` we should keep.
"""
unstacker = unstacker_func(self.values.T)
new_items = unstacker.get_new_columns()
new_placement = new_columns.get_indexer(new_items)
new_values, mask = unstacker.get_new_values()
mask = mask.any(0)
new_values = new_values.T[mask]
new_placement = new_placement[mask]
blocks = [make_block(new_values, placement=new_placement)]
return blocks, mask
def quantile(self, qs, interpolation="linear", axis=0):
"""
compute the quantiles of the
Parameters
----------
qs: a scalar or list of the quantiles to be computed
interpolation: type of interpolation, default 'linear'
axis: axis to compute, default 0
Returns
-------
Block
"""
# We should always have ndim == 2 becase Series dispatches to DataFrame
assert self.ndim == 2
values = self.get_values()
is_empty = values.shape[axis] == 0
orig_scalar = not is_list_like(qs)
if orig_scalar:
# make list-like, unpack later
qs = [qs]
if is_empty:
# create the array of na_values
# 2d len(values) * len(qs)
result = np.repeat(
np.array([self.fill_value] * len(qs)), len(values)
).reshape(len(values), len(qs))
else:
# asarray needed for Sparse, see GH#24600
mask = np.asarray(isna(values))
result = nanpercentile(
values,
np.array(qs) * 100,
axis=axis,
na_value=self.fill_value,
mask=mask,
ndim=values.ndim,
interpolation=interpolation,
)
result = np.array(result, copy=False)
result = result.T
if orig_scalar and not lib.is_scalar(result):
# result could be scalar in case with is_empty and self.ndim == 1
assert result.shape[-1] == 1, result.shape
result = result[..., 0]
result = lib.item_from_zerodim(result)
ndim = np.ndim(result)
return make_block(result, placement=np.arange(len(result)), ndim=ndim)
def _replace_coerce(
self, to_replace, value, inplace=True, regex=False, convert=False, mask=None
):
"""
Replace value corresponding to the given boolean array with another
value.
Parameters
----------
to_replace : object or pattern
Scalar to replace or regular expression to match.
value : object
Replacement object.
inplace : bool, default False
Perform inplace modification.
regex : bool, default False
If true, perform regular expression substitution.
convert : bool, default True
If true, try to coerce any object types to better types.
mask : array-like of bool, optional
True indicate corresponding element is ignored.
Returns
-------
A new block if there is anything to replace or the original block.
"""
if mask.any():
if not regex:
self = self.coerce_to_target_dtype(value)
return self.putmask(mask, value, inplace=inplace)
else:
return self._replace_single(
to_replace,
value,
inplace=inplace,
regex=regex,
convert=convert,
mask=mask,
)
return self
class NonConsolidatableMixIn:
""" hold methods for the nonconsolidatable blocks """
_can_consolidate = False
_verify_integrity = False
_validate_ndim = False
def __init__(self, values, placement, ndim=None):
"""Initialize a non-consolidatable block.
'ndim' may be inferred from 'placement'.
This will call continue to call __init__ for the other base
classes mixed in with this Mixin.
"""
# Placement must be converted to BlockPlacement so that we can check
# its length
if not isinstance(placement, libinternals.BlockPlacement):
placement = libinternals.BlockPlacement(placement)
# Maybe infer ndim from placement
if ndim is None:
if len(placement) != 1:
ndim = 1
else:
ndim = 2
super().__init__(values, placement, ndim=ndim)
@property
def shape(self):
if self.ndim == 1:
return ((len(self.values)),)
return (len(self.mgr_locs), len(self.values))
def iget(self, col):
if self.ndim == 2 and isinstance(col, tuple):
col, loc = col
if not com.is_null_slice(col) and col != 0:
raise IndexError("{0} only contains one item".format(self))
elif isinstance(col, slice):
if col != slice(None):
raise NotImplementedError(col)
return self.values[[loc]]
return self.values[loc]
else:
if col != 0:
raise IndexError("{0} only contains one item".format(self))
return self.values
def should_store(self, value):
return isinstance(value, self._holder)
def set(self, locs, values, check=False):
assert locs.tolist() == [0]
self.values = values
def putmask(self, mask, new, align=True, inplace=False, axis=0, transpose=False):
"""
putmask the data to the block; we must be a single block and not
generate other blocks
return the resulting block
Parameters
----------
mask : the condition to respect
new : a ndarray/object
align : boolean, perform alignment on other/cond, default is True
inplace : perform inplace modification, default is False
Returns
-------
a new block, the result of the putmask
"""
inplace = validate_bool_kwarg(inplace, "inplace")
# use block's copy logic.
# .values may be an Index which does shallow copy by default
new_values = self.values if inplace else self.copy().values
if isinstance(new, np.ndarray) and len(new) == len(mask):
new = new[mask]
mask = _safe_reshape(mask, new_values.shape)
new_values[mask] = new
return [self.make_block(values=new_values)]
def _get_unstack_items(self, unstacker, new_columns):
"""
Get the placement, values, and mask for a Block unstack.
This is shared between ObjectBlock and ExtensionBlock. They
differ in that ObjectBlock passes the values, while ExtensionBlock
passes the dummy ndarray of positions to be used by a take
later.
Parameters
----------
unstacker : pandas.core.reshape.reshape._Unstacker
new_columns : Index
All columns of the unstacked BlockManager.
Returns
-------
new_placement : ndarray[int]
The placement of the new columns in `new_columns`.
new_values : Union[ndarray, ExtensionArray]
The first return value from _Unstacker.get_new_values.
mask : ndarray[bool]
The second return value from _Unstacker.get_new_values.
"""
# shared with ExtensionBlock
new_items = unstacker.get_new_columns()
new_placement = new_columns.get_indexer(new_items)
new_values, mask = unstacker.get_new_values()
mask = mask.any(0)
return new_placement, new_values, mask
class ExtensionBlock(NonConsolidatableMixIn, Block):
"""Block for holding extension types.
Notes
-----
This holds all 3rd-party extension array types. It's also the immediate
parent class for our internal extension types' blocks, CategoricalBlock.
ExtensionArrays are limited to 1-D.
"""
is_extension = True
def __init__(self, values, placement, ndim=None):
values = self._maybe_coerce_values(values)
super().__init__(values, placement, ndim)
def _maybe_coerce_values(self, values):
"""
Unbox to an extension array.
This will unbox an ExtensionArray stored in an Index or Series.
ExtensionArrays pass through. No dtype coercion is done.
Parameters
----------
values : Index, Series, ExtensionArray
Returns
-------
ExtensionArray
"""
return extract_array(values)
@property
def _holder(self):
# For extension blocks, the holder is values-dependent.
return type(self.values)
@property
def fill_value(self):
# Used in reindex_indexer
return self.values.dtype.na_value
@property
def _can_hold_na(self):
# The default ExtensionArray._can_hold_na is True
return self._holder._can_hold_na
@property
def is_view(self):
"""Extension arrays are never treated as views."""
return False
@property
def is_numeric(self):
return self.values.dtype._is_numeric
def setitem(self, indexer, value):
"""Set the value inplace, returning a same-typed block.
This differs from Block.setitem by not allowing setitem to change
the dtype of the Block.
Parameters
----------
indexer : tuple, list-like, array-like, slice
The subset of self.values to set
value : object
The value being set
Returns
-------
Block
Notes
-----
`indexer` is a direct slice/positional indexer. `value` must
be a compatible shape.
"""
if isinstance(indexer, tuple):
# we are always 1-D
indexer = indexer[0]
check_setitem_lengths(indexer, value, self.values)
self.values[indexer] = value
return self
def get_values(self, dtype=None):
# ExtensionArrays must be iterable, so this works.
values = np.asarray(self.values)
if values.ndim == self.ndim - 1:
values = values.reshape((1,) + values.shape)
return values
def to_dense(self):
return np.asarray(self.values)
def to_native_types(self, slicer=None, na_rep="nan", quoting=None, **kwargs):
"""override to use ExtensionArray astype for the conversion"""
values = self.values
if slicer is not None:
values = values[slicer]
mask = isna(values)
try:
values = values.astype(str)
values[mask] = na_rep
except Exception:
# eg SparseArray does not support setitem, needs to be converted to ndarray
return super().to_native_types(slicer, na_rep, quoting, **kwargs)
# we are expected to return a 2-d ndarray
return values.reshape(1, len(values))
def take_nd(self, indexer, axis=0, new_mgr_locs=None, fill_tuple=None):
"""
Take values according to indexer and return them as a block.
"""
if fill_tuple is None:
fill_value = None
else:
fill_value = fill_tuple[0]
# axis doesn't matter; we are really a single-dim object
# but are passed the axis depending on the calling routing
# if its REALLY axis 0, then this will be a reindex and not a take
new_values = self.values.take(indexer, fill_value=fill_value, allow_fill=True)
# Called from three places in managers, all of which satisfy
# this assertion
assert not (self.ndim == 1 and new_mgr_locs is None)
if new_mgr_locs is None:
new_mgr_locs = self.mgr_locs
return self.make_block_same_class(new_values, new_mgr_locs)
def _can_hold_element(self, element: Any) -> bool:
# XXX: We may need to think about pushing this onto the array.
# We're doing the same as CategoricalBlock here.
return True
def _slice(self, slicer):
""" return a slice of my values """
# slice the category
# return same dims as we currently have
if isinstance(slicer, tuple) and len(slicer) == 2:
if not com.is_null_slice(slicer[0]):
raise AssertionError("invalid slicing for a 1-ndim categorical")
slicer = slicer[1]
return self.values[slicer]
def concat_same_type(self, to_concat, placement=None):
"""
Concatenate list of single blocks of the same type.
"""
values = self._holder._concat_same_type([blk.values for blk in to_concat])
placement = placement or slice(0, len(values), 1)
return self.make_block_same_class(values, ndim=self.ndim, placement=placement)
def fillna(self, value, limit=None, inplace=False, downcast=None):
values = self.values if inplace else self.values.copy()
values = values.fillna(value=value, limit=limit)
return [
self.make_block_same_class(
values=values, placement=self.mgr_locs, ndim=self.ndim
)
]
def interpolate(
self, method="pad", axis=0, inplace=False, limit=None, fill_value=None, **kwargs
):
values = self.values if inplace else self.values.copy()
return self.make_block_same_class(
values=values.fillna(value=fill_value, method=method, limit=limit),
placement=self.mgr_locs,
)
def shift(
self,
periods: int,
axis: libinternals.BlockPlacement = 0,
fill_value: Any = None,
) -> List["ExtensionBlock"]:
"""
Shift the block by `periods`.
Dispatches to underlying ExtensionArray and re-boxes in an
ExtensionBlock.
"""
return [
self.make_block_same_class(
self.values.shift(periods=periods, fill_value=fill_value),
placement=self.mgr_locs,
ndim=self.ndim,
)
]
def where(
self,
other,
cond,
align=True,
errors="raise",
try_cast: bool = False,
axis: int = 0,
) -> List["Block"]:
if isinstance(other, ABCDataFrame):
# ExtensionArrays are 1-D, so if we get here then
# `other` should be a DataFrame with a single column.
assert other.shape[1] == 1
other = other.iloc[:, 0]
other = extract_array(other, extract_numpy=True)
if isinstance(cond, ABCDataFrame):
assert cond.shape[1] == 1
cond = cond.iloc[:, 0]
cond = extract_array(cond, extract_numpy=True)
if lib.is_scalar(other) and isna(other):
# The default `other` for Series / Frame is np.nan
# we want to replace that with the correct NA value
# for the type
other = self.dtype.na_value
if is_sparse(self.values):
# TODO(SparseArray.__setitem__): remove this if condition
# We need to re-infer the type of the data after doing the
# where, for cases where the subtypes don't match
dtype = None
else:
dtype = self.dtype
result = self.values.copy()
icond = ~cond
if lib.is_scalar(other):
set_other = other
else:
set_other = other[icond]
try:
result[icond] = set_other
except (NotImplementedError, TypeError):
# NotImplementedError for class not implementing `__setitem__`
# TypeError for SparseArray, which implements just to raise
# a TypeError
result = self._holder._from_sequence(
np.where(cond, self.values, other), dtype=dtype
)
return [self.make_block_same_class(result, placement=self.mgr_locs)]
@property
def _ftype(self):
return getattr(self.values, "_pandas_ftype", Block._ftype)
def _unstack(self, unstacker_func, new_columns, n_rows, fill_value):
# ExtensionArray-safe unstack.
# We override ObjectBlock._unstack, which unstacks directly on the
# values of the array. For EA-backed blocks, this would require
# converting to a 2-D ndarray of objects.
# Instead, we unstack an ndarray of integer positions, followed by
# a `take` on the actual values.
dummy_arr = np.arange(n_rows)
dummy_unstacker = functools.partial(unstacker_func, fill_value=-1)
unstacker = dummy_unstacker(dummy_arr)
new_placement, new_values, mask = self._get_unstack_items(
unstacker, new_columns
)
blocks = [
self.make_block_same_class(
self.values.take(indices, allow_fill=True, fill_value=fill_value),
[place],
)
for indices, place in zip(new_values.T, new_placement)
]
return blocks, mask
class ObjectValuesExtensionBlock(ExtensionBlock):
"""
Block providing backwards-compatibility for `.values`.
Used by PeriodArray and IntervalArray to ensure that
Series[T].values is an ndarray of objects.
"""
def external_values(self, dtype=None):
return self.values.astype(object)
class NumericBlock(Block):
__slots__ = ()
is_numeric = True
_can_hold_na = True
class FloatOrComplexBlock(NumericBlock):
__slots__ = ()
def equals(self, other) -> bool:
if self.dtype != other.dtype or self.shape != other.shape:
return False
left, right = self.values, other.values
return ((left == right) | (np.isnan(left) & np.isnan(right))).all()
class FloatBlock(FloatOrComplexBlock):
__slots__ = ()
is_float = True
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return issubclass(tipo.type, (np.floating, np.integer)) and not issubclass(
tipo.type, (np.datetime64, np.timedelta64)
)
return isinstance(
element, (float, int, np.floating, np.int_)
) and not isinstance(
element,
(bool, np.bool_, datetime, timedelta, np.datetime64, np.timedelta64),
)
def to_native_types(
self,
slicer=None,
na_rep="",
float_format=None,
decimal=".",
quoting=None,
**kwargs,
):
""" convert to our native types format, slicing if desired """
values = self.values
if slicer is not None:
values = values[:, slicer]
# see gh-13418: no special formatting is desired at the
# output (important for appropriate 'quoting' behaviour),
# so do not pass it through the FloatArrayFormatter
if float_format is None and decimal == ".":
mask = isna(values)
if not quoting:
values = values.astype(str)
else:
values = np.array(values, dtype="object")
values[mask] = na_rep
return values
from pandas.io.formats.format import FloatArrayFormatter
formatter = FloatArrayFormatter(
values,
na_rep=na_rep,
float_format=float_format,
decimal=decimal,
quoting=quoting,
fixed_width=False,
)
return formatter.get_result_as_array()
def should_store(self, value):
# when inserting a column should not coerce integers to floats
# unnecessarily
return issubclass(value.dtype.type, np.floating) and value.dtype == self.dtype
class ComplexBlock(FloatOrComplexBlock):
__slots__ = ()
is_complex = True
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return issubclass(tipo.type, (np.floating, np.integer, np.complexfloating))
return isinstance(
element, (float, int, complex, np.float_, np.int_)
) and not isinstance(element, (bool, np.bool_))
def should_store(self, value):
return issubclass(value.dtype.type, np.complexfloating)
class IntBlock(NumericBlock):
__slots__ = ()
is_integer = True
_can_hold_na = False
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return (
issubclass(tipo.type, np.integer)
and not issubclass(tipo.type, (np.datetime64, np.timedelta64))
and self.dtype.itemsize >= tipo.itemsize
)
return is_integer(element)
def should_store(self, value):
return is_integer_dtype(value) and value.dtype == self.dtype
class DatetimeLikeBlockMixin:
"""Mixin class for DatetimeBlock, DatetimeTZBlock, and TimedeltaBlock."""
@property
def _holder(self):
return DatetimeArray
@property
def fill_value(self):
return np.datetime64("NaT", "ns")
def get_values(self, dtype=None):
"""
return object dtype as boxed values, such as Timestamps/Timedelta
"""
if is_object_dtype(dtype):
values = self.values.ravel()
result = self._holder(values).astype(object)
return result.reshape(self.values.shape)
return self.values
class DatetimeBlock(DatetimeLikeBlockMixin, Block):
__slots__ = ()
is_datetime = True
def __init__(self, values, placement, ndim=None):
values = self._maybe_coerce_values(values)
super().__init__(values, placement=placement, ndim=ndim)
@property
def _can_hold_na(self):
return True
def _maybe_coerce_values(self, values):
"""
Input validation for values passed to __init__. Ensure that
we have datetime64ns, coercing if necessary.
Parameters
----------
values : array-like
Must be convertible to datetime64
Returns
-------
values : ndarray[datetime64ns]
Overridden by DatetimeTZBlock.
"""
if values.dtype != _NS_DTYPE:
values = conversion.ensure_datetime64ns(values)
if isinstance(values, DatetimeArray):
values = values._data
assert isinstance(values, np.ndarray), type(values)
return values
def _astype(self, dtype, **kwargs):
"""
these automatically copy, so copy=True has no effect
raise on an except if raise == True
"""
dtype = pandas_dtype(dtype)
# if we are passed a datetime64[ns, tz]
if is_datetime64tz_dtype(dtype):
values = self.values
if getattr(values, "tz", None) is None:
values = DatetimeArray(values).tz_localize("UTC")
values = values.tz_convert(dtype.tz)
return self.make_block(values)
# delegate
return super()._astype(dtype=dtype, **kwargs)
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
if self.is_datetimetz:
# require exact match, since non-nano does not exist
return is_dtype_equal(tipo, self.dtype) or is_valid_nat_for_dtype(
element, self.dtype
)
# GH#27419 if we get a non-nano datetime64 object
return is_datetime64_dtype(tipo)
elif element is NaT:
return True
elif isinstance(element, datetime):
if self.is_datetimetz:
return tz_compare(element.tzinfo, self.dtype.tz)
return element.tzinfo is None
return is_valid_nat_for_dtype(element, self.dtype)
def to_native_types(
self, slicer=None, na_rep=None, date_format=None, quoting=None, **kwargs
):
""" convert to our native types format, slicing if desired """
values = self.values
i8values = self.values.view("i8")
if slicer is not None:
values = values[..., slicer]
i8values = i8values[..., slicer]
from pandas.io.formats.format import _get_format_datetime64_from_values
fmt = _get_format_datetime64_from_values(values, date_format)
result = tslib.format_array_from_datetime(
i8values.ravel(),
tz=getattr(self.values, "tz", None),
format=fmt,
na_rep=na_rep,
).reshape(i8values.shape)
return np.atleast_2d(result)
def should_store(self, value):
return (
issubclass(value.dtype.type, np.datetime64)
and not is_datetime64tz_dtype(value)
and not is_extension_array_dtype(value)
)
def set(self, locs, values):
"""
Modify Block in-place with new item value
Returns
-------
None
"""
values = conversion.ensure_datetime64ns(values, copy=False)
self.values[locs] = values
def external_values(self):
return np.asarray(self.values.astype("datetime64[ns]", copy=False))
class DatetimeTZBlock(ExtensionBlock, DatetimeBlock):
""" implement a datetime64 block with a tz attribute """
__slots__ = ()
is_datetimetz = True
is_extension = True
_can_hold_element = DatetimeBlock._can_hold_element
to_native_types = DatetimeBlock.to_native_types
fill_value = np.datetime64("NaT", "ns")
@property
def _holder(self):
return DatetimeArray
def _maybe_coerce_values(self, values):
"""Input validation for values passed to __init__. Ensure that
we have datetime64TZ, coercing if necessary.
Parameters
----------
values : array-like
Must be convertible to datetime64
Returns
-------
values : DatetimeArray
"""
if not isinstance(values, self._holder):
values = self._holder(values)
if values.tz is None:
raise ValueError("cannot create a DatetimeTZBlock without a tz")
return values
@property
def is_view(self):
""" return a boolean if I am possibly a view """
# check the ndarray values of the DatetimeIndex values
return self.values._data.base is not None
def get_values(self, dtype=None):
"""
Returns an ndarray of values.
Parameters
----------
dtype : np.dtype
Only `object`-like dtypes are respected here (not sure
why).
Returns
-------
values : ndarray
When ``dtype=object``, then and object-dtype ndarray of
boxed values is returned. Otherwise, an M8[ns] ndarray
is returned.
DatetimeArray is always 1-d. ``get_values`` will reshape
the return value to be the same dimensionality as the
block.
"""
values = self.values
if is_object_dtype(dtype):
values = values.astype(object)
values = np.asarray(values)
if self.ndim == 2:
# Ensure that our shape is correct for DataFrame.
# ExtensionArrays are always 1-D, even in a DataFrame when
# the analogous NumPy-backed column would be a 2-D ndarray.
values = values.reshape(1, -1)
return values
def to_dense(self):
# we request M8[ns] dtype here, even though it discards tzinfo,
# as lots of code (e.g. anything using values_from_object)
# expects that behavior.
return np.asarray(self.values, dtype=_NS_DTYPE)
def _slice(self, slicer):
""" return a slice of my values """
if isinstance(slicer, tuple):
col, loc = slicer
if not com.is_null_slice(col) and col != 0:
raise IndexError("{0} only contains one item".format(self))
return self.values[loc]
return self.values[slicer]
def diff(self, n: int, axis: int = 0) -> List["Block"]:
"""
1st discrete difference.
Parameters
----------
n : int
Number of periods to diff.
axis : int, default 0
Axis to diff upon.
Returns
-------
A list with a new TimeDeltaBlock.
Notes
-----
The arguments here are mimicking shift so they are called correctly
by apply.
"""
if axis == 0:
# Cannot currently calculate diff across multiple blocks since this
# function is invoked via apply
raise NotImplementedError
new_values = (self.values - self.shift(n, axis=axis)[0].values).asi8
# Reshape the new_values like how algos.diff does for timedelta data
new_values = new_values.reshape(1, len(new_values))
new_values = new_values.astype("timedelta64[ns]")
return [TimeDeltaBlock(new_values, placement=self.mgr_locs.indexer)]
def concat_same_type(self, to_concat, placement=None):
# need to handle concat([tz1, tz2]) here, since DatetimeArray
# only handles cases where all the tzs are the same.
# Instead of placing the condition here, it could also go into the
# is_uniform_join_units check, but I'm not sure what is better.
if len({x.dtype for x in to_concat}) > 1:
values = concat_datetime([x.values for x in to_concat])
placement = placement or slice(0, len(values), 1)
if self.ndim > 1:
values = np.atleast_2d(values)
return ObjectBlock(values, ndim=self.ndim, placement=placement)
return super().concat_same_type(to_concat, placement)
def fillna(self, value, limit=None, inplace=False, downcast=None):
# We support filling a DatetimeTZ with a `value` whose timezone
# is different by coercing to object.
if self._can_hold_element(value):
return super().fillna(value, limit, inplace, downcast)
# different timezones, or a non-tz
return self.astype(object).fillna(
value, limit=limit, inplace=inplace, downcast=downcast
)
def setitem(self, indexer, value):
# https://github.com/pandas-dev/pandas/issues/24020
# Need a dedicated setitem until #24020 (type promotion in setitem
# for extension arrays) is designed and implemented.
if self._can_hold_element(value) or (
isinstance(indexer, np.ndarray) and indexer.size == 0
):
return super().setitem(indexer, value)
obj_vals = self.values.astype(object)
newb = make_block(
obj_vals, placement=self.mgr_locs, klass=ObjectBlock, ndim=self.ndim
)
return newb.setitem(indexer, value)
def equals(self, other) -> bool:
# override for significant performance improvement
if self.dtype != other.dtype or self.shape != other.shape:
return False
return (self.values.view("i8") == other.values.view("i8")).all()
def quantile(self, qs, interpolation="linear", axis=0):
naive = self.values.view("M8[ns]")
# kludge for 2D block with 1D values
naive = naive.reshape(self.shape)
blk = self.make_block(naive)
res_blk = blk.quantile(qs, interpolation=interpolation, axis=axis)
# ravel is kludge for 2D block with 1D values, assumes column-like
aware = self._holder(res_blk.values.ravel(), dtype=self.dtype)
return self.make_block_same_class(aware, ndim=res_blk.ndim)
class TimeDeltaBlock(DatetimeLikeBlockMixin, IntBlock):
__slots__ = ()
is_timedelta = True
_can_hold_na = True
is_numeric = False
fill_value = np.timedelta64("NaT", "ns")
def __init__(self, values, placement, ndim=None):
if values.dtype != _TD_DTYPE:
values = conversion.ensure_timedelta64ns(values)
if isinstance(values, TimedeltaArray):
values = values._data
assert isinstance(values, np.ndarray), type(values)
super().__init__(values, placement=placement, ndim=ndim)
@property
def _holder(self):
return TimedeltaArray
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return issubclass(tipo.type, np.timedelta64)
elif element is NaT:
return True
elif isinstance(element, (timedelta, np.timedelta64)):
return True
return is_valid_nat_for_dtype(element, self.dtype)
def fillna(self, value, **kwargs):
# allow filling with integers to be
# interpreted as nanoseconds
if is_integer(value):
# Deprecation GH#24694, GH#19233
warnings.warn(
"Passing integers to fillna is deprecated, will "
"raise a TypeError in a future version. To retain "
"the old behavior, pass pd.Timedelta(seconds=n) "
"instead.",
FutureWarning,
stacklevel=6,
)
value = Timedelta(value, unit="s")
return super().fillna(value, **kwargs)
def should_store(self, value):
return issubclass(
value.dtype.type, np.timedelta64
) and not is_extension_array_dtype(value)
def to_native_types(self, slicer=None, na_rep=None, quoting=None, **kwargs):
""" convert to our native types format, slicing if desired """
values = self.values
if slicer is not None:
values = values[:, slicer]
mask = isna(values)
rvalues = np.empty(values.shape, dtype=object)
if na_rep is None:
na_rep = "NaT"
rvalues[mask] = na_rep
imask = (~mask).ravel()
# FIXME:
# should use the formats.format.Timedelta64Formatter here
# to figure what format to pass to the Timedelta
# e.g. to not show the decimals say
rvalues.flat[imask] = np.array(
[Timedelta(val)._repr_base(format="all") for val in values.ravel()[imask]],
dtype=object,
)
return rvalues
def external_values(self, dtype=None):
return np.asarray(self.values.astype("timedelta64[ns]", copy=False))
class BoolBlock(NumericBlock):
__slots__ = ()
is_bool = True
_can_hold_na = False
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return issubclass(tipo.type, np.bool_)
return isinstance(element, (bool, np.bool_))
def should_store(self, value):
return issubclass(value.dtype.type, np.bool_) and not is_extension_array_dtype(
value
)
def replace(
self, to_replace, value, inplace=False, filter=None, regex=False, convert=True
):
inplace = validate_bool_kwarg(inplace, "inplace")
to_replace_values = np.atleast_1d(to_replace)
if not np.can_cast(to_replace_values, bool):
return self
return super().replace(
to_replace,
value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
class ObjectBlock(Block):
__slots__ = ()
is_object = True
_can_hold_na = True
def __init__(self, values, placement=None, ndim=2):
if issubclass(values.dtype.type, str):
values = np.array(values, dtype=object)
super().__init__(values, ndim=ndim, placement=placement)
@property
def is_bool(self):
""" we can be a bool if we have only bool values but are of type
object
"""
return lib.is_bool_array(self.values.ravel())
def convert(
self,
copy: bool = True,
datetime: bool = True,
numeric: bool = True,
timedelta: bool = True,
coerce: bool = False,
):
""" attempt to coerce any object types to better types return a copy of
the block (if copy = True) by definition we ARE an ObjectBlock!!!!!
can return multiple blocks!
"""
# operate column-by-column
def f(mask, val, idx):
shape = val.shape
values = soft_convert_objects(
val.ravel(),
datetime=datetime,
numeric=numeric,
timedelta=timedelta,
coerce=coerce,
copy=copy,
)
if isinstance(values, np.ndarray):
# TODO: allow EA once reshape is supported
values = values.reshape(shape)
values = _block_shape(values, ndim=self.ndim)
return values
if self.ndim == 2:
blocks = self.split_and_operate(None, f, False)
else:
values = f(None, self.values.ravel(), None)
blocks = [make_block(values, ndim=self.ndim, placement=self.mgr_locs)]
return blocks
def _maybe_downcast(self, blocks: List["Block"], downcast=None) -> List["Block"]:
if downcast is not None:
return blocks
# split and convert the blocks
return _extend_blocks([b.convert(datetime=True, numeric=False) for b in blocks])
def _can_hold_element(self, element: Any) -> bool:
return True
def should_store(self, value):
return not (
issubclass(
value.dtype.type,
(np.integer, np.floating, np.complexfloating, np.datetime64, np.bool_),
)
or is_extension_array_dtype(value)
)
def replace(
self, to_replace, value, inplace=False, filter=None, regex=False, convert=True
):
to_rep_is_list = is_list_like(to_replace)
value_is_list = is_list_like(value)
both_lists = to_rep_is_list and value_is_list
either_list = to_rep_is_list or value_is_list
result_blocks = []
blocks = [self]
if not either_list and is_re(to_replace):
return self._replace_single(
to_replace,
value,
inplace=inplace,
filter=filter,
regex=True,
convert=convert,
)
elif not (either_list or regex):
return super().replace(
to_replace,
value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
elif both_lists:
for to_rep, v in zip(to_replace, value):
result_blocks = []
for b in blocks:
result = b._replace_single(
to_rep,
v,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
result_blocks = _extend_blocks(result, result_blocks)
blocks = result_blocks
return result_blocks
elif to_rep_is_list and regex:
for to_rep in to_replace:
result_blocks = []
for b in blocks:
result = b._replace_single(
to_rep,
value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
result_blocks = _extend_blocks(result, result_blocks)
blocks = result_blocks
return result_blocks
return self._replace_single(
to_replace,
value,
inplace=inplace,
filter=filter,
convert=convert,
regex=regex,
)
def _replace_single(
self,
to_replace,
value,
inplace=False,
filter=None,
regex=False,
convert=True,
mask=None,
):
"""
Replace elements by the given value.
Parameters
----------
to_replace : object or pattern
Scalar to replace or regular expression to match.
value : object
Replacement object.
inplace : bool, default False
Perform inplace modification.
filter : list, optional
regex : bool, default False
If true, perform regular expression substitution.
convert : bool, default True
If true, try to coerce any object types to better types.
mask : array-like of bool, optional
True indicate corresponding element is ignored.
Returns
-------
a new block, the result after replacing
"""
inplace = validate_bool_kwarg(inplace, "inplace")
# to_replace is regex compilable
to_rep_re = regex and is_re_compilable(to_replace)
# regex is regex compilable
regex_re = is_re_compilable(regex)
# only one will survive
if to_rep_re and regex_re:
raise AssertionError(
"only one of to_replace and regex can be regex compilable"
)
# if regex was passed as something that can be a regex (rather than a
# boolean)
if regex_re:
to_replace = regex
regex = regex_re or to_rep_re
# try to get the pattern attribute (compiled re) or it's a string
if is_re(to_replace):
pattern = to_replace.pattern
else:
pattern = to_replace
# if the pattern is not empty and to_replace is either a string or a
# regex
if regex and pattern:
rx = re.compile(to_replace)
else:
# if the thing to replace is not a string or compiled regex call
# the superclass method -> to_replace is some kind of object
return super().replace(
to_replace, value, inplace=inplace, filter=filter, regex=regex
)
new_values = self.values if inplace else self.values.copy()
# deal with replacing values with objects (strings) that match but
# whose replacement is not a string (numeric, nan, object)
if isna(value) or not isinstance(value, str):
def re_replacer(s):
if is_re(rx) and isinstance(s, str):
return value if rx.search(s) is not None else s
else:
return s
else:
# value is guaranteed to be a string here, s can be either a string
# or null if it's null it gets returned
def re_replacer(s):
if is_re(rx) and isinstance(s, str):
return rx.sub(value, s)
else:
return s
f = np.vectorize(re_replacer, otypes=[self.dtype])
if filter is None:
filt = slice(None)
else:
filt = self.mgr_locs.isin(filter).nonzero()[0]
if mask is None:
new_values[filt] = f(new_values[filt])
else:
new_values[filt][mask] = f(new_values[filt][mask])
# convert
block = self.make_block(new_values)
if convert:
block = block.convert(numeric=False)
return block
def _replace_coerce(
self, to_replace, value, inplace=True, regex=False, convert=False, mask=None
):
"""
Replace value corresponding to the given boolean array with another
value.
Parameters
----------
to_replace : object or pattern
Scalar to replace or regular expression to match.
value : object
Replacement object.
inplace : bool, default False
Perform inplace modification.
regex : bool, default False
If true, perform regular expression substitution.
convert : bool, default True
If true, try to coerce any object types to better types.
mask : array-like of bool, optional
True indicate corresponding element is ignored.
Returns
-------
A new block if there is anything to replace or the original block.
"""
if mask.any():
block = super()._replace_coerce(
to_replace=to_replace,
value=value,
inplace=inplace,
regex=regex,
convert=convert,
mask=mask,
)
if convert:
block = [b.convert(numeric=False, copy=True) for b in block]
return block
return self
class CategoricalBlock(ExtensionBlock):
__slots__ = ()
is_categorical = True
_verify_integrity = True
_can_hold_na = True
_concatenator = staticmethod(concat_categorical)
def __init__(self, values, placement, ndim=None):
# coerce to categorical if we can
values = extract_array(values)
assert isinstance(values, Categorical), type(values)
super().__init__(values, placement=placement, ndim=ndim)
@property
def _holder(self):
return Categorical
@property
def array_dtype(self):
""" the dtype to return if I want to construct this block as an
array
"""
return np.object_
def to_dense(self):
# Categorical.get_values returns a DatetimeIndex for datetime
# categories, so we can't simply use `np.asarray(self.values)` like
# other types.
return self.values._internal_get_values()
def to_native_types(self, slicer=None, na_rep="", quoting=None, **kwargs):
""" convert to our native types format, slicing if desired """
values = self.values
if slicer is not None:
# Categorical is always one dimension
values = values[slicer]
mask = isna(values)
values = np.array(values, dtype="object")
values[mask] = na_rep
# we are expected to return a 2-d ndarray
return values.reshape(1, len(values))
def concat_same_type(self, to_concat, placement=None):
"""
Concatenate list of single blocks of the same type.
Note that this CategoricalBlock._concat_same_type *may* not
return a CategoricalBlock. When the categories in `to_concat`
differ, this will return an object ndarray.
If / when we decide we don't like that behavior:
1. Change Categorical._concat_same_type to use union_categoricals
2. Delete this method.
"""
values = self._concatenator(
[blk.values for blk in to_concat], axis=self.ndim - 1
)
# not using self.make_block_same_class as values can be object dtype
return make_block(
values, placement=placement or slice(0, len(values), 1), ndim=self.ndim
)
def where(
self,
other,
cond,
align=True,
errors="raise",
try_cast: bool = False,
axis: int = 0,
) -> List["Block"]:
# TODO(CategoricalBlock.where):
# This can all be deleted in favor of ExtensionBlock.where once
# we enforce the deprecation.
object_msg = (
"Implicitly converting categorical to object-dtype ndarray. "
"One or more of the values in 'other' are not present in this "
"categorical's categories. A future version of pandas will raise "
"a ValueError when 'other' contains different categories.\n\n"
"To preserve the current behavior, add the new categories to "
"the categorical before calling 'where', or convert the "
"categorical to a different dtype."
)
try:
# Attempt to do preserve categorical dtype.
result = super().where(other, cond, align, errors, try_cast, axis)
except (TypeError, ValueError):
warnings.warn(object_msg, FutureWarning, stacklevel=6)
result = self.astype(object).where(
other, cond, align=align, errors=errors, try_cast=try_cast, axis=axis
)
return result
def replace(
self,
to_replace,
value,
inplace: bool = False,
filter=None,
regex: bool = False,
convert: bool = True,
):
inplace = validate_bool_kwarg(inplace, "inplace")
result = self if inplace else self.copy()
if filter is None: # replace was called on a series
result.values.replace(to_replace, value, inplace=True)
if convert:
return result.convert(numeric=False, copy=not inplace)
else:
return result
else: # replace was called on a DataFrame
if not isna(value):
result.values.add_categories(value, inplace=True)
return super(CategoricalBlock, result).replace(
to_replace, value, inplace, filter, regex, convert
)
# -----------------------------------------------------------------
# Constructor Helpers
def get_block_type(values, dtype=None):
"""
Find the appropriate Block subclass to use for the given values and dtype.
Parameters
----------
values : ndarray-like
dtype : numpy or pandas dtype
Returns
-------
cls : class, subclass of Block
"""
dtype = dtype or values.dtype
vtype = dtype.type
if is_sparse(dtype):
# Need this first(ish) so that Sparse[datetime] is sparse
cls = ExtensionBlock
elif is_categorical(values):
cls = CategoricalBlock
elif issubclass(vtype, np.datetime64):
assert not is_datetime64tz_dtype(values)
cls = DatetimeBlock
elif is_datetime64tz_dtype(values):
cls = DatetimeTZBlock
elif is_interval_dtype(dtype) or is_period_dtype(dtype):
cls = ObjectValuesExtensionBlock
elif is_extension_array_dtype(values):
cls = ExtensionBlock
elif issubclass(vtype, np.floating):
cls = FloatBlock
elif issubclass(vtype, np.timedelta64):
assert issubclass(vtype, np.integer)
cls = TimeDeltaBlock
elif issubclass(vtype, np.complexfloating):
cls = ComplexBlock
elif issubclass(vtype, np.integer):
cls = IntBlock
elif dtype == np.bool_:
cls = BoolBlock
else:
cls = ObjectBlock
return cls
def make_block(values, placement, klass=None, ndim=None, dtype=None, fastpath=None):
# Ensure that we don't allow PandasArray / PandasDtype in internals.
# For now, blocks should be backed by ndarrays when possible.
if isinstance(values, ABCPandasArray):
values = values.to_numpy()
if ndim and ndim > 1:
values = np.atleast_2d(values)
if isinstance(dtype, PandasDtype):
dtype = dtype.numpy_dtype
if fastpath is not None:
# GH#19265 pyarrow is passing this
warnings.warn(
"fastpath argument is deprecated, will be removed in a future release.",
FutureWarning,
)
if klass is None:
dtype = dtype or values.dtype
klass = get_block_type(values, dtype)
elif klass is DatetimeTZBlock and not is_datetime64tz_dtype(values):
# TODO: This is no longer hit internally; does it need to be retained
# for e.g. pyarrow?
values = DatetimeArray._simple_new(values, dtype=dtype)
return klass(values, ndim=ndim, placement=placement)
# -----------------------------------------------------------------
def _extend_blocks(result, blocks=None):
""" return a new extended blocks, givin the result """
from pandas.core.internals import BlockManager
if blocks is None:
blocks = []
if isinstance(result, list):
for r in result:
if isinstance(r, list):
blocks.extend(r)
else:
blocks.append(r)
elif isinstance(result, BlockManager):
blocks.extend(result.blocks)
else:
blocks.append(result)
return blocks
def _block_shape(values, ndim=1, shape=None):
""" guarantee the shape of the values to be at least 1 d """
if values.ndim < ndim:
if shape is None:
shape = values.shape
if not is_extension_array_dtype(values):
# TODO: https://github.com/pandas-dev/pandas/issues/23023
# block.shape is incorrect for "2D" ExtensionArrays
# We can't, and don't need to, reshape.
values = values.reshape(tuple((1,) + shape))
return values
def _merge_blocks(blocks, dtype=None, _can_consolidate=True):
if len(blocks) == 1:
return blocks[0]
if _can_consolidate:
if dtype is None:
if len({b.dtype for b in blocks}) != 1:
raise AssertionError("_merge_blocks are invalid!")
dtype = blocks[0].dtype
# FIXME: optimization potential in case all mgrs contain slices and
# combination of those slices is a slice, too.
new_mgr_locs = np.concatenate([b.mgr_locs.as_array for b in blocks])
new_values = np.vstack([b.values for b in blocks])
argsort = np.argsort(new_mgr_locs)
new_values = new_values[argsort]
new_mgr_locs = new_mgr_locs[argsort]
return make_block(new_values, placement=new_mgr_locs)
# no merge
return blocks
def _safe_reshape(arr, new_shape):
"""
If possible, reshape `arr` to have shape `new_shape`,
with a couple of exceptions (see gh-13012):
1) If `arr` is a ExtensionArray or Index, `arr` will be
returned as is.
2) If `arr` is a Series, the `_values` attribute will
be reshaped and returned.
Parameters
----------
arr : array-like, object to be reshaped
new_shape : int or tuple of ints, the new shape
"""
if isinstance(arr, ABCSeries):
arr = arr._values
if not isinstance(arr, ABCExtensionArray):
arr = arr.reshape(new_shape)
return arr
def _putmask_smart(v, mask, n):
"""
Return a new ndarray, try to preserve dtype if possible.
Parameters
----------
v : `values`, updated in-place (array like)
mask : np.ndarray
Applies to both sides (array like).
n : `new values` either scalar or an array like aligned with `values`
Returns
-------
values : ndarray with updated values
this *may* be a copy of the original
See Also
--------
ndarray.putmask
"""
# we cannot use np.asarray() here as we cannot have conversions
# that numpy does when numeric are mixed with strings
# n should be the length of the mask or a scalar here
if not is_list_like(n):
n = np.repeat(n, len(mask))
# see if we are only masking values that if putted
# will work in the current dtype
try:
nn = n[mask]
except TypeError:
# TypeError: only integer scalar arrays can be converted to a scalar index
pass
else:
# make sure that we have a nullable type
# if we have nulls
if not _isna_compat(v, nn[0]):
pass
elif not (is_float_dtype(nn.dtype) or is_integer_dtype(nn.dtype)):
# only compare integers/floats
pass
elif not (is_float_dtype(v.dtype) or is_integer_dtype(v.dtype)):
# only compare integers/floats
pass
else:
# we ignore ComplexWarning here
with warnings.catch_warnings(record=True):
warnings.simplefilter("ignore", np.ComplexWarning)
nn_at = nn.astype(v.dtype)
comp = nn == nn_at
if is_list_like(comp) and comp.all():
nv = v.copy()
nv[mask] = nn_at
return nv
n = np.asarray(n)
def _putmask_preserve(nv, n):
try:
nv[mask] = n[mask]
except (IndexError, ValueError):
nv[mask] = n
return nv
# preserves dtype if possible
if v.dtype.kind == n.dtype.kind:
return _putmask_preserve(v, n)
# change the dtype if needed
dtype, _ = maybe_promote(n.dtype)
if is_extension_array_dtype(v.dtype) and is_object_dtype(dtype):
v = v._internal_get_values(dtype)
else:
v = v.astype(dtype)
return _putmask_preserve(v, n)
from datetime import datetime, timedelta
import functools
import inspect
import re
from typing import Any, List
import warnings
import numpy as np
from pandas._libs import NaT, algos as libalgos, lib, tslib, writers
from pandas._libs.index import convert_scalar
import pandas._libs.internals as libinternals
from pandas._libs.tslibs import Timedelta, conversion
from pandas._libs.tslibs.timezones import tz_compare
from pandas.util._validators import validate_bool_kwarg
from pandas.core.dtypes.cast import (
astype_nansafe,
find_common_type,
infer_dtype_from,
infer_dtype_from_scalar,
maybe_downcast_numeric,
maybe_downcast_to_dtype,
maybe_infer_dtype_type,
maybe_promote,
maybe_upcast,
soft_convert_objects,
)
from pandas.core.dtypes.common import (
_NS_DTYPE,
_TD_DTYPE,
ensure_platform_int,
is_bool_dtype,
is_categorical,
is_categorical_dtype,
is_datetime64_dtype,
is_datetime64tz_dtype,
is_dtype_equal,
is_extension_array_dtype,
is_float_dtype,
is_integer,
is_integer_dtype,
is_interval_dtype,
is_list_like,
is_object_dtype,
is_period_dtype,
is_re,
is_re_compilable,
is_sparse,
is_timedelta64_dtype,
pandas_dtype,
)
from pandas.core.dtypes.concat import concat_categorical, concat_datetime
from pandas.core.dtypes.dtypes import CategoricalDtype, ExtensionDtype
from pandas.core.dtypes.generic import (
ABCDataFrame,
ABCExtensionArray,
ABCPandasArray,
ABCSeries,
)
from pandas.core.dtypes.missing import (
_isna_compat,
array_equivalent,
is_valid_nat_for_dtype,
isna,
)
import pandas.core.algorithms as algos
from pandas.core.arrays import Categorical, DatetimeArray, PandasDtype, TimedeltaArray
from pandas.core.base import PandasObject
import pandas.core.common as com
from pandas.core.construction import extract_array
from pandas.core.indexers import (
check_setitem_lengths,
is_empty_indexer,
is_scalar_indexer,
)
import pandas.core.missing as missing
from pandas.core.nanops import nanpercentile
from pandas.io.formats.printing import pprint_thing
class Block(PandasObject):
"""
Canonical n-dimensional unit of homogeneous dtype contained in a pandas
data structure
Index-ignorant; let the container take care of that
"""
__slots__ = ["_mgr_locs", "values", "ndim"]
is_numeric = False
is_float = False
is_integer = False
is_complex = False
is_datetime = False
is_datetimetz = False
is_timedelta = False
is_bool = False
is_object = False
is_categorical = False
is_extension = False
_can_hold_na = False
_can_consolidate = True
_verify_integrity = True
_validate_ndim = True
_ftype = "dense"
_concatenator = staticmethod(np.concatenate)
def __init__(self, values, placement, ndim=None):
self.ndim = self._check_ndim(values, ndim)
self.mgr_locs = placement
self.values = values
if self._validate_ndim and self.ndim and len(self.mgr_locs) != len(self.values):
raise ValueError(
"Wrong number of items passed {val}, placement implies "
"{mgr}".format(val=len(self.values), mgr=len(self.mgr_locs))
)
def _check_ndim(self, values, ndim):
"""
ndim inference and validation.
Infers ndim from 'values' if not provided to __init__.
Validates that values.ndim and ndim are consistent if and only if
the class variable '_validate_ndim' is True.
Parameters
----------
values : array-like
ndim : int or None
Returns
-------
ndim : int
Raises
------
ValueError : the number of dimensions do not match
"""
if ndim is None:
ndim = values.ndim
if self._validate_ndim and values.ndim != ndim:
msg = "Wrong number of dimensions. values.ndim != ndim [{} != {}]"
raise ValueError(msg.format(values.ndim, ndim))
return ndim
@property
def _holder(self):
"""The array-like that can hold the underlying values.
None for 'Block', overridden by subclasses that don't
use an ndarray.
"""
return None
@property
def _consolidate_key(self):
return (self._can_consolidate, self.dtype.name)
@property
def _is_single_block(self):
return self.ndim == 1
@property
def is_view(self):
""" return a boolean if I am possibly a view """
return self.values.base is not None
@property
def is_datelike(self):
""" return True if I am a non-datelike """
return self.is_datetime or self.is_timedelta
def is_categorical_astype(self, dtype):
"""
validate that we have a astypeable to categorical,
returns a boolean if we are a categorical
"""
if dtype is Categorical or dtype is CategoricalDtype:
# this is a pd.Categorical, but is not
# a valid type for astypeing
raise TypeError("invalid type {0} for astype".format(dtype))
elif is_categorical_dtype(dtype):
return True
return False
def external_values(self, dtype=None):
""" return an outside world format, currently just the ndarray """
return self.values
def internal_values(self, dtype=None):
""" return an internal format, currently just the ndarray
this should be the pure internal API format
"""
return self.values
def get_values(self, dtype=None):
"""
return an internal format, currently just the ndarray
this is often overridden to handle to_dense like operations
"""
if is_object_dtype(dtype):
return self.values.astype(object)
return self.values
def get_block_values(self, dtype=None):
"""
This is used in the JSON C code
"""
return self.get_values(dtype=dtype)
def to_dense(self):
return self.values.view()
@property
def fill_value(self):
return np.nan
@property
def mgr_locs(self):
return self._mgr_locs
@mgr_locs.setter
def mgr_locs(self, new_mgr_locs):
if not isinstance(new_mgr_locs, libinternals.BlockPlacement):
new_mgr_locs = libinternals.BlockPlacement(new_mgr_locs)
self._mgr_locs = new_mgr_locs
@property
def array_dtype(self):
""" the dtype to return if I want to construct this block as an
array
"""
return self.dtype
def make_block(self, values, placement=None):
"""
Create a new block, with type inference propagate any values that are
not specified
"""
if placement is None:
placement = self.mgr_locs
return make_block(values, placement=placement, ndim=self.ndim)
def make_block_same_class(self, values, placement=None, ndim=None, dtype=None):
""" Wrap given values in a block of same type as self. """
if dtype is not None:
# issue 19431 fastparquet is passing this
warnings.warn(
"dtype argument is deprecated, will be removed in a future release.",
FutureWarning,
)
if placement is None:
placement = self.mgr_locs
if ndim is None:
ndim = self.ndim
return make_block(
values, placement=placement, ndim=ndim, klass=self.__class__, dtype=dtype
)
def __repr__(self) -> str:
# don't want to print out all of the items here
name = pprint_thing(self.__class__.__name__)
if self._is_single_block:
result = "{name}: {len} dtype: {dtype}".format(
name=name, len=len(self), dtype=self.dtype
)
else:
shape = " x ".join(pprint_thing(s) for s in self.shape)
result = "{name}: {index}, {shape}, dtype: {dtype}".format(
name=name,
index=pprint_thing(self.mgr_locs.indexer),
shape=shape,
dtype=self.dtype,
)
return result
def __len__(self) -> int:
return len(self.values)
def __getstate__(self):
return self.mgr_locs.indexer, self.values
def __setstate__(self, state):
self.mgr_locs = libinternals.BlockPlacement(state[0])
self.values = state[1]
self.ndim = self.values.ndim
def _slice(self, slicer):
""" return a slice of my values """
return self.values[slicer]
def getitem_block(self, slicer, new_mgr_locs=None):
"""
Perform __getitem__-like, return result as block.
As of now, only supports slices that preserve dimensionality.
"""
if new_mgr_locs is None:
if isinstance(slicer, tuple):
axis0_slicer = slicer[0]
else:
axis0_slicer = slicer
new_mgr_locs = self.mgr_locs[axis0_slicer]
new_values = self._slice(slicer)
if self._validate_ndim and new_values.ndim != self.ndim:
raise ValueError("Only same dim slicing is allowed")
return self.make_block_same_class(new_values, new_mgr_locs)
@property
def shape(self):
return self.values.shape
@property
def dtype(self):
return self.values.dtype
@property
def ftype(self):
if getattr(self.values, "_pandas_ftype", False):
dtype = self.dtype.subtype
else:
dtype = self.dtype
return "{dtype}:{ftype}".format(dtype=dtype, ftype=self._ftype)
def merge(self, other):
return _merge_blocks([self, other])
def concat_same_type(self, to_concat, placement=None):
"""
Concatenate list of single blocks of the same type.
"""
values = self._concatenator(
[blk.values for blk in to_concat], axis=self.ndim - 1
)
return self.make_block_same_class(
values, placement=placement or slice(0, len(values), 1)
)
def iget(self, i):
return self.values[i]
def set(self, locs, values):
"""
Modify Block in-place with new item value
Returns
-------
None
"""
self.values[locs] = values
def delete(self, loc):
"""
Delete given loc(-s) from block in-place.
"""
self.values = np.delete(self.values, loc, 0)
self.mgr_locs = self.mgr_locs.delete(loc)
def apply(self, func, **kwargs):
""" apply the function to my values; return a block if we are not
one
"""
with np.errstate(all="ignore"):
result = func(self.values, **kwargs)
if not isinstance(result, Block):
result = self.make_block(values=_block_shape(result, ndim=self.ndim))
return result
def fillna(self, value, limit=None, inplace=False, downcast=None):
""" fillna on the block with the value. If we fail, then convert to
ObjectBlock and try again
"""
inplace = validate_bool_kwarg(inplace, "inplace")
mask = isna(self.values)
if limit is not None:
limit = libalgos._validate_limit(None, limit=limit)
mask[mask.cumsum(self.ndim - 1) > limit] = False
if not self._can_hold_na:
if inplace:
return self
else:
return self.copy()
if self._can_hold_element(value):
# equivalent: _try_coerce_args(value) would not raise
blocks = self.putmask(mask, value, inplace=inplace)
return self._maybe_downcast(blocks, downcast)
# we can't process the value, but nothing to do
if not mask.any():
return self if inplace else self.copy()
# operate column-by-column
def f(mask, val, idx):
block = self.coerce_to_target_dtype(value)
# slice out our block
if idx is not None:
# i.e. self.ndim == 2
block = block.getitem_block(slice(idx, idx + 1))
return block.fillna(value, limit=limit, inplace=inplace, downcast=None)
return self.split_and_operate(None, f, inplace)
def split_and_operate(self, mask, f, inplace: bool):
"""
split the block per-column, and apply the callable f
per-column, return a new block for each. Handle
masking which will not change a block unless needed.
Parameters
----------
mask : 2-d boolean mask
f : callable accepting (1d-mask, 1d values, indexer)
inplace : boolean
Returns
-------
list of blocks
"""
if mask is None:
mask = np.broadcast_to(True, shape=self.shape)
new_values = self.values
def make_a_block(nv, ref_loc):
if isinstance(nv, list):
assert len(nv) == 1, nv
assert isinstance(nv[0], Block)
block = nv[0]
else:
# Put back the dimension that was taken from it and make
# a block out of the result.
nv = _block_shape(nv, ndim=self.ndim)
block = self.make_block(values=nv, placement=ref_loc)
return block
# ndim == 1
if self.ndim == 1:
if mask.any():
nv = f(mask, new_values, None)
else:
nv = new_values if inplace else new_values.copy()
block = make_a_block(nv, self.mgr_locs)
return [block]
# ndim > 1
new_blocks = []
for i, ref_loc in enumerate(self.mgr_locs):
m = mask[i]
v = new_values[i]
# need a new block
if m.any():
nv = f(m, v, i)
else:
nv = v if inplace else v.copy()
block = make_a_block(nv, [ref_loc])
new_blocks.append(block)
return new_blocks
def _maybe_downcast(self, blocks: List["Block"], downcast=None) -> List["Block"]:
# no need to downcast our float
# unless indicated
if downcast is None and (
self.is_float or self.is_timedelta or self.is_datetime
):
return blocks
return _extend_blocks([b.downcast(downcast) for b in blocks])
def downcast(self, dtypes=None):
""" try to downcast each item to the dict of dtypes if present """
# turn it off completely
if dtypes is False:
return self
values = self.values
# single block handling
if self._is_single_block:
# try to cast all non-floats here
if dtypes is None:
dtypes = "infer"
nv = maybe_downcast_to_dtype(values, dtypes)
return self.make_block(nv)
# ndim > 1
if dtypes is None:
return self
if not (dtypes == "infer" or isinstance(dtypes, dict)):
raise ValueError(
"downcast must have a dictionary or 'infer' as its argument"
)
elif dtypes != "infer":
raise AssertionError("dtypes as dict is not supported yet")
# operate column-by-column
# this is expensive as it splits the blocks items-by-item
def f(mask, val, idx):
val = maybe_downcast_to_dtype(val, dtype="infer")
return val
return self.split_and_operate(None, f, False)
def astype(self, dtype, copy=False, errors="raise", **kwargs):
return self._astype(dtype, copy=copy, errors=errors, **kwargs)
def _astype(self, dtype, copy=False, errors="raise", **kwargs):
"""Coerce to the new type
Parameters
----------
dtype : str, dtype convertible
copy : boolean, default False
copy if indicated
errors : str, {'raise', 'ignore'}, default 'ignore'
- ``raise`` : allow exceptions to be raised
- ``ignore`` : suppress exceptions. On error return original object
Returns
-------
Block
"""
errors_legal_values = ("raise", "ignore")
if errors not in errors_legal_values:
invalid_arg = (
"Expected value of kwarg 'errors' to be one of {}. "
"Supplied value is '{}'".format(list(errors_legal_values), errors)
)
raise ValueError(invalid_arg)
if inspect.isclass(dtype) and issubclass(dtype, ExtensionDtype):
msg = (
"Expected an instance of {}, but got the class instead. "
"Try instantiating 'dtype'.".format(dtype.__name__)
)
raise TypeError(msg)
# may need to convert to categorical
if self.is_categorical_astype(dtype):
if is_categorical_dtype(self.values):
# GH 10696/18593: update an existing categorical efficiently
return self.make_block(self.values.astype(dtype, copy=copy))
return self.make_block(Categorical(self.values, dtype=dtype))
dtype = pandas_dtype(dtype)
# astype processing
if is_dtype_equal(self.dtype, dtype):
if copy:
return self.copy()
return self
# force the copy here
if self.is_extension:
# TODO: Should we try/except this astype?
values = self.values.astype(dtype)
else:
if issubclass(dtype.type, str):
# use native type formatting for datetime/tz/timedelta
if self.is_datelike:
values = self.to_native_types()
# astype formatting
else:
values = self.get_values()
else:
values = self.get_values(dtype=dtype)
# _astype_nansafe works fine with 1-d only
vals1d = values.ravel()
try:
values = astype_nansafe(vals1d, dtype, copy=True)
except (ValueError, TypeError):
# e.g. astype_nansafe can fail on object-dtype of strings
# trying to convert to float
if errors == "raise":
raise
newb = self.copy() if copy else self
return newb
# TODO(extension)
# should we make this attribute?
if isinstance(values, np.ndarray):
values = values.reshape(self.shape)
newb = make_block(values, placement=self.mgr_locs, ndim=self.ndim)
if newb.is_numeric and self.is_numeric:
if newb.shape != self.shape:
raise TypeError(
"cannot set astype for copy = [{copy}] for dtype "
"({dtype} [{shape}]) to different shape "
"({newb_dtype} [{newb_shape}])".format(
copy=copy,
dtype=self.dtype.name,
shape=self.shape,
newb_dtype=newb.dtype.name,
newb_shape=newb.shape,
)
)
return newb
def convert(
self,
copy: bool = True,
datetime: bool = True,
numeric: bool = True,
timedelta: bool = True,
coerce: bool = False,
):
""" attempt to coerce any object types to better types return a copy
of the block (if copy = True) by definition we are not an ObjectBlock
here!
"""
return self.copy() if copy else self
def _can_hold_element(self, element: Any) -> bool:
""" require the same dtype as ourselves """
dtype = self.values.dtype.type
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return issubclass(tipo.type, dtype)
return isinstance(element, dtype)
def to_native_types(self, slicer=None, na_rep="nan", quoting=None, **kwargs):
""" convert to our native types format, slicing if desired """
values = self.get_values()
if slicer is not None:
values = values[:, slicer]
mask = isna(values)
if not self.is_object and not quoting:
itemsize = writers.word_len(na_rep)
values = values.astype("<U{size}".format(size=itemsize))
else:
values = np.array(values, dtype="object")
values[mask] = na_rep
return values
# block actions #
def copy(self, deep=True):
""" copy constructor """
values = self.values
if deep:
values = values.copy()
return self.make_block_same_class(values, ndim=self.ndim)
def replace(
self, to_replace, value, inplace=False, filter=None, regex=False, convert=True
):
"""replace the to_replace value with value, possible to create new
blocks here this is just a call to putmask. regex is not used here.
It is used in ObjectBlocks. It is here for API compatibility.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
original_to_replace = to_replace
# If we cannot replace with own dtype, convert to ObjectBlock and
# retry
if not self._can_hold_element(to_replace):
if not isinstance(to_replace, list):
if inplace:
return [self]
return [self.copy()]
to_replace = [x for x in to_replace if self._can_hold_element(x)]
if not len(to_replace):
# GH#28084 avoid costly checks since we can infer
# that there is nothing to replace in this block
if inplace:
return [self]
return [self.copy()]
if len(to_replace) == 1:
# _can_hold_element checks have reduced this back to the
# scalar case and we can avoid a costly object cast
return self.replace(
to_replace[0],
value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
# GH 22083, TypeError or ValueError occurred within error handling
# causes infinite loop. Cast and retry only if not objectblock.
if is_object_dtype(self):
raise AssertionError
# try again with a compatible block
block = self.astype(object)
return block.replace(
to_replace=to_replace,
value=value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
values = self.values
if lib.is_scalar(to_replace) and isinstance(values, np.ndarray):
# The only non-DatetimeLike class that also has a non-trivial
# try_coerce_args is ObjectBlock, but that overrides replace,
# so does not get here.
to_replace = convert_scalar(values, to_replace)
mask = missing.mask_missing(values, to_replace)
if filter is not None:
filtered_out = ~self.mgr_locs.isin(filter)
mask[filtered_out.nonzero()[0]] = False
if not mask.any():
if inplace:
return [self]
return [self.copy()]
try:
blocks = self.putmask(mask, value, inplace=inplace)
# Note: it is _not_ the case that self._can_hold_element(value)
# is always true at this point. In particular, that can fail
# for:
# "2u" with bool-dtype, float-dtype
# 0.5 with int64-dtype
# np.nan with int64-dtype
except (TypeError, ValueError):
# GH 22083, TypeError or ValueError occurred within error handling
# causes infinite loop. Cast and retry only if not objectblock.
if is_object_dtype(self):
raise
assert not self._can_hold_element(value), value
# try again with a compatible block
block = self.astype(object)
return block.replace(
to_replace=original_to_replace,
value=value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
if convert:
blocks = [b.convert(numeric=False, copy=not inplace) for b in blocks]
return blocks
def _replace_single(self, *args, **kwargs):
""" no-op on a non-ObjectBlock """
return self if kwargs["inplace"] else self.copy()
def setitem(self, indexer, value):
"""
Set the value inplace, returning a a maybe different typed block.
Parameters
----------
indexer : tuple, list-like, array-like, slice
The subset of self.values to set
value : object
The value being set
Returns
-------
Block
Notes
-----
`indexer` is a direct slice/positional indexer. `value` must
be a compatible shape.
"""
transpose = self.ndim == 2
# coerce None values, if appropriate
if value is None:
if self.is_numeric:
value = np.nan
# coerce if block dtype can store value
values = self.values
if self._can_hold_element(value):
# We only get here for non-Extension Blocks, so _try_coerce_args
# is only relevant for DatetimeBlock and TimedeltaBlock
if lib.is_scalar(value):
value = convert_scalar(values, value)
else:
# current dtype cannot store value, coerce to common dtype
find_dtype = False
if hasattr(value, "dtype"):
dtype = value.dtype
find_dtype = True
elif lib.is_scalar(value) and not isna(value):
dtype, _ = infer_dtype_from_scalar(value, pandas_dtype=True)
find_dtype = True
if find_dtype:
dtype = find_common_type([values.dtype, dtype])
if not is_dtype_equal(self.dtype, dtype):
b = self.astype(dtype)
return b.setitem(indexer, value)
# value must be storeable at this moment
if is_extension_array_dtype(getattr(value, "dtype", None)):
# We need to be careful not to allow through strings that
# can be parsed to EADtypes
arr_value = value
else:
arr_value = np.array(value)
# cast the values to a type that can hold nan (if necessary)
if not self._can_hold_element(value):
dtype, _ = maybe_promote(arr_value.dtype)
values = values.astype(dtype)
if transpose:
values = values.T
# length checking
check_setitem_lengths(indexer, value, values)
if is_empty_indexer(indexer, arr_value):
# GH#8669 empty indexers
pass
elif is_scalar_indexer(indexer, arr_value):
# setting a single element for each dim and with a rhs that could
# be e.g. a list; see GH#6043
values[indexer] = value
# if we are an exact match (ex-broadcasting),
# then use the resultant dtype
elif (
len(arr_value.shape)
and arr_value.shape[0] == values.shape[0]
and arr_value.size == values.size
):
values[indexer] = value
try:
values = values.astype(arr_value.dtype)
except ValueError:
pass
# set
else:
values[indexer] = value
if transpose:
values = values.T
block = self.make_block(values)
return block
def putmask(self, mask, new, align=True, inplace=False, axis=0, transpose=False):
""" putmask the data to the block; it is possible that we may create a
new dtype of block
return the resulting block(s)
Parameters
----------
mask : the condition to respect
new : a ndarray/object
align : boolean, perform alignment on other/cond, default is True
inplace : perform inplace modification, default is False
axis : int
transpose : boolean
Set to True if self is stored with axes reversed
Returns
-------
a list of new blocks, the result of the putmask
"""
new_values = self.values if inplace else self.values.copy()
new = getattr(new, "values", new)
mask = getattr(mask, "values", mask)
# if we are passed a scalar None, convert it here
if not is_list_like(new) and isna(new) and not self.is_object:
# FIXME: make sure we have compatible NA
new = self.fill_value
if self._can_hold_element(new):
# We only get here for non-Extension Blocks, so _try_coerce_args
# is only relevant for DatetimeBlock and TimedeltaBlock
if lib.is_scalar(new):
new = convert_scalar(new_values, new)
if transpose:
new_values = new_values.T
# If the default repeat behavior in np.putmask would go in the
# wrong direction, then explicitly repeat and reshape new instead
if getattr(new, "ndim", 0) >= 1:
if self.ndim - 1 == new.ndim and axis == 1:
new = np.repeat(new, new_values.shape[-1]).reshape(self.shape)
new = new.astype(new_values.dtype)
# we require exact matches between the len of the
# values we are setting (or is compat). np.putmask
# doesn't check this and will simply truncate / pad
# the output, but we want sane error messages
#
# TODO: this prob needs some better checking
# for 2D cases
if (
is_list_like(new)
and np.any(mask[mask])
and getattr(new, "ndim", 1) == 1
):
if not (
mask.shape[-1] == len(new)
or mask[mask].shape[-1] == len(new)
or len(new) == 1
):
raise ValueError("cannot assign mismatch length to masked array")
np.putmask(new_values, mask, new)
# maybe upcast me
elif mask.any():
if transpose:
mask = mask.T
if isinstance(new, np.ndarray):
new = new.T
axis = new_values.ndim - axis - 1
# Pseudo-broadcast
if getattr(new, "ndim", 0) >= 1:
if self.ndim - 1 == new.ndim:
new_shape = list(new.shape)
new_shape.insert(axis, 1)
new = new.reshape(tuple(new_shape))
# operate column-by-column
def f(mask, val, idx):
if idx is None:
# ndim==1 case.
n = new
else:
if isinstance(new, np.ndarray):
n = np.squeeze(new[idx % new.shape[0]])
else:
n = np.array(new)
# type of the new block
dtype, _ = maybe_promote(n.dtype)
# we need to explicitly astype here to make a copy
n = n.astype(dtype)
nv = _putmask_smart(val, mask, n)
return nv
new_blocks = self.split_and_operate(mask, f, inplace)
return new_blocks
if inplace:
return [self]
if transpose:
new_values = new_values.T
return [self.make_block(new_values)]
def coerce_to_target_dtype(self, other):
"""
coerce the current block to a dtype compat for other
we will return a block, possibly object, and not raise
we can also safely try to coerce to the same dtype
and will receive the same block
"""
# if we cannot then coerce to object
dtype, _ = infer_dtype_from(other, pandas_dtype=True)
if is_dtype_equal(self.dtype, dtype):
return self
if self.is_bool or is_object_dtype(dtype) or is_bool_dtype(dtype):
# we don't upcast to bool
return self.astype(object)
elif (self.is_float or self.is_complex) and (
is_integer_dtype(dtype) or is_float_dtype(dtype)
):
# don't coerce float/complex to int
return self
elif (
self.is_datetime
or is_datetime64_dtype(dtype)
or is_datetime64tz_dtype(dtype)
):
# not a datetime
if not (
(is_datetime64_dtype(dtype) or is_datetime64tz_dtype(dtype))
and self.is_datetime
):
return self.astype(object)
# don't upcast timezone with different timezone or no timezone
mytz = getattr(self.dtype, "tz", None)
othertz = getattr(dtype, "tz", None)
if not tz_compare(mytz, othertz):
return self.astype(object)
raise AssertionError(
"possible recursion in "
"coerce_to_target_dtype: {} {}".format(self, other)
)
elif self.is_timedelta or is_timedelta64_dtype(dtype):
# not a timedelta
if not (is_timedelta64_dtype(dtype) and self.is_timedelta):
return self.astype(object)
raise AssertionError(
"possible recursion in "
"coerce_to_target_dtype: {} {}".format(self, other)
)
try:
return self.astype(dtype)
except (ValueError, TypeError, OverflowError):
return self.astype(object)
def interpolate(
self,
method="pad",
axis=0,
index=None,
values=None,
inplace=False,
limit=None,
limit_direction="forward",
limit_area=None,
fill_value=None,
coerce=False,
downcast=None,
**kwargs,
):
inplace = validate_bool_kwarg(inplace, "inplace")
def check_int_bool(self, inplace):
# Only FloatBlocks will contain NaNs.
# timedelta subclasses IntBlock
if (self.is_bool or self.is_integer) and not self.is_timedelta:
if inplace:
return self
else:
return self.copy()
# a fill na type method
try:
m = missing.clean_fill_method(method)
except ValueError:
m = None
if m is not None:
r = check_int_bool(self, inplace)
if r is not None:
return r
return self._interpolate_with_fill(
method=m,
axis=axis,
inplace=inplace,
limit=limit,
fill_value=fill_value,
coerce=coerce,
downcast=downcast,
)
# validate the interp method
m = missing.clean_interp_method(method, **kwargs)
r = check_int_bool(self, inplace)
if r is not None:
return r
return self._interpolate(
method=m,
index=index,
values=values,
axis=axis,
limit=limit,
limit_direction=limit_direction,
limit_area=limit_area,
fill_value=fill_value,
inplace=inplace,
downcast=downcast,
**kwargs,
)
def _interpolate_with_fill(
self,
method="pad",
axis=0,
inplace=False,
limit=None,
fill_value=None,
coerce=False,
downcast=None,
):
""" fillna but using the interpolate machinery """
inplace = validate_bool_kwarg(inplace, "inplace")
# if we are coercing, then don't force the conversion
# if the block can't hold the type
if coerce:
if not self._can_hold_na:
if inplace:
return [self]
else:
return [self.copy()]
values = self.values if inplace else self.values.copy()
# We only get here for non-ExtensionBlock
fill_value = convert_scalar(self.values, fill_value)
values = missing.interpolate_2d(
values,
method=method,
axis=axis,
limit=limit,
fill_value=fill_value,
dtype=self.dtype,
)
blocks = [self.make_block_same_class(values, ndim=self.ndim)]
return self._maybe_downcast(blocks, downcast)
def _interpolate(
self,
method=None,
index=None,
values=None,
fill_value=None,
axis=0,
limit=None,
limit_direction="forward",
limit_area=None,
inplace=False,
downcast=None,
**kwargs,
):
""" interpolate using scipy wrappers """
inplace = validate_bool_kwarg(inplace, "inplace")
data = self.values if inplace else self.values.copy()
# only deal with floats
if not self.is_float:
if not self.is_integer:
return self
data = data.astype(np.float64)
if fill_value is None:
fill_value = self.fill_value
if method in ("krogh", "piecewise_polynomial", "pchip"):
if not index.is_monotonic:
raise ValueError(
"{0} interpolation requires that the "
"index be monotonic.".format(method)
)
# process 1-d slices in the axis direction
def func(x):
# process a 1-d slice, returning it
# should the axis argument be handled below in apply_along_axis?
# i.e. not an arg to missing.interpolate_1d
return missing.interpolate_1d(
index,
x,
method=method,
limit=limit,
limit_direction=limit_direction,
limit_area=limit_area,
fill_value=fill_value,
bounds_error=False,
**kwargs,
)
# interp each column independently
interp_values = np.apply_along_axis(func, axis, data)
blocks = [self.make_block_same_class(interp_values)]
return self._maybe_downcast(blocks, downcast)
def take_nd(self, indexer, axis, new_mgr_locs=None, fill_tuple=None):
"""
Take values according to indexer and return them as a block.bb
"""
# algos.take_nd dispatches for DatetimeTZBlock, CategoricalBlock
# so need to preserve types
# sparse is treated like an ndarray, but needs .get_values() shaping
values = self.values
if fill_tuple is None:
fill_value = self.fill_value
allow_fill = False
else:
fill_value = fill_tuple[0]
allow_fill = True
new_values = algos.take_nd(
values, indexer, axis=axis, allow_fill=allow_fill, fill_value=fill_value
)
# Called from three places in managers, all of which satisfy
# this assertion
assert not (axis == 0 and new_mgr_locs is None)
if new_mgr_locs is None:
new_mgr_locs = self.mgr_locs
if not is_dtype_equal(new_values.dtype, self.dtype):
return self.make_block(new_values, new_mgr_locs)
else:
return self.make_block_same_class(new_values, new_mgr_locs)
def diff(self, n: int, axis: int = 1) -> List["Block"]:
""" return block for the diff of the values """
new_values = algos.diff(self.values, n, axis=axis)
return [self.make_block(values=new_values)]
def shift(self, periods, axis=0, fill_value=None):
""" shift the block by periods, possibly upcast """
# convert integer to float if necessary. need to do a lot more than
# that, handle boolean etc also
new_values, fill_value = maybe_upcast(self.values, fill_value)
# make sure array sent to np.roll is c_contiguous
f_ordered = new_values.flags.f_contiguous
if f_ordered:
new_values = new_values.T
axis = new_values.ndim - axis - 1
if np.prod(new_values.shape):
new_values = np.roll(new_values, ensure_platform_int(periods), axis=axis)
axis_indexer = [slice(None)] * self.ndim
if periods > 0:
axis_indexer[axis] = slice(None, periods)
else:
axis_indexer[axis] = slice(periods, None)
new_values[tuple(axis_indexer)] = fill_value
# restore original order
if f_ordered:
new_values = new_values.T
return [self.make_block(new_values)]
def where(
self,
other,
cond,
align=True,
errors="raise",
try_cast: bool = False,
axis: int = 0,
) -> List["Block"]:
"""
evaluate the block; return result block(s) from the result
Parameters
----------
other : a ndarray/object
cond : the condition to respect
align : boolean, perform alignment on other/cond
errors : str, {'raise', 'ignore'}, default 'raise'
- ``raise`` : allow exceptions to be raised
- ``ignore`` : suppress exceptions. On error return original object
axis : int
Returns
-------
a new block(s), the result of the func
"""
import pandas.core.computation.expressions as expressions
assert errors in ["raise", "ignore"]
transpose = self.ndim == 2
values = self.values
orig_other = other
if transpose:
values = values.T
other = getattr(other, "_values", getattr(other, "values", other))
cond = getattr(cond, "values", cond)
# If the default broadcasting would go in the wrong direction, then
# explicitly reshape other instead
if getattr(other, "ndim", 0) >= 1:
if values.ndim - 1 == other.ndim and axis == 1:
other = other.reshape(tuple(other.shape + (1,)))
elif transpose and values.ndim == self.ndim - 1:
cond = cond.T
if not hasattr(cond, "shape"):
raise ValueError("where must have a condition that is ndarray like")
# our where function
def func(cond, values, other):
if not (
(self.is_integer or self.is_bool)
and lib.is_float(other)
and np.isnan(other)
):
# np.where will cast integer array to floats in this case
if not self._can_hold_element(other):
raise TypeError
if lib.is_scalar(other) and isinstance(values, np.ndarray):
other = convert_scalar(values, other)
fastres = expressions.where(cond, values, other)
return fastres
if cond.ravel().all():
result = values
else:
# see if we can operate on the entire block, or need item-by-item
# or if we are a single block (ndim == 1)
try:
result = func(cond, values, other)
except TypeError:
# we cannot coerce, return a compat dtype
# we are explicitly ignoring errors
block = self.coerce_to_target_dtype(other)
blocks = block.where(
orig_other,
cond,
align=align,
errors=errors,
try_cast=try_cast,
axis=axis,
)
return self._maybe_downcast(blocks, "infer")
if self._can_hold_na or self.ndim == 1:
if transpose:
result = result.T
return [self.make_block(result)]
# might need to separate out blocks
axis = cond.ndim - 1
cond = cond.swapaxes(axis, 0)
mask = np.array([cond[i].all() for i in range(cond.shape[0])], dtype=bool)
result_blocks = []
for m in [mask, ~mask]:
if m.any():
taken = result.take(m.nonzero()[0], axis=axis)
r = maybe_downcast_numeric(taken, self.dtype)
nb = self.make_block(r.T, placement=self.mgr_locs[m])
result_blocks.append(nb)
return result_blocks
def equals(self, other) -> bool:
if self.dtype != other.dtype or self.shape != other.shape:
return False
return array_equivalent(self.values, other.values)
def _unstack(self, unstacker_func, new_columns, n_rows, fill_value):
"""Return a list of unstacked blocks of self
Parameters
----------
unstacker_func : callable
Partially applied unstacker.
new_columns : Index
All columns of the unstacked BlockManager.
n_rows : int
Only used in ExtensionBlock._unstack
fill_value : int
Only used in ExtensionBlock._unstack
Returns
-------
blocks : list of Block
New blocks of unstacked values.
mask : array_like of bool
The mask of columns of `blocks` we should keep.
"""
unstacker = unstacker_func(self.values.T)
new_items = unstacker.get_new_columns()
new_placement = new_columns.get_indexer(new_items)
new_values, mask = unstacker.get_new_values()
mask = mask.any(0)
new_values = new_values.T[mask]
new_placement = new_placement[mask]
blocks = [make_block(new_values, placement=new_placement)]
return blocks, mask
def quantile(self, qs, interpolation="linear", axis=0):
"""
compute the quantiles of the
Parameters
----------
qs: a scalar or list of the quantiles to be computed
interpolation: type of interpolation, default 'linear'
axis: axis to compute, default 0
Returns
-------
Block
"""
# We should always have ndim == 2 becase Series dispatches to DataFrame
assert self.ndim == 2
values = self.get_values()
is_empty = values.shape[axis] == 0
orig_scalar = not is_list_like(qs)
if orig_scalar:
# make list-like, unpack later
qs = [qs]
if is_empty:
# create the array of na_values
# 2d len(values) * len(qs)
result = np.repeat(
np.array([self.fill_value] * len(qs)), len(values)
).reshape(len(values), len(qs))
else:
# asarray needed for Sparse, see GH#24600
mask = np.asarray(isna(values))
result = nanpercentile(
values,
np.array(qs) * 100,
axis=axis,
na_value=self.fill_value,
mask=mask,
ndim=values.ndim,
interpolation=interpolation,
)
result = np.array(result, copy=False)
result = result.T
if orig_scalar and not lib.is_scalar(result):
# result could be scalar in case with is_empty and self.ndim == 1
assert result.shape[-1] == 1, result.shape
result = result[..., 0]
result = lib.item_from_zerodim(result)
ndim = np.ndim(result)
return make_block(result, placement=np.arange(len(result)), ndim=ndim)
def _replace_coerce(
self, to_replace, value, inplace=True, regex=False, convert=False, mask=None
):
"""
Replace value corresponding to the given boolean array with another
value.
Parameters
----------
to_replace : object or pattern
Scalar to replace or regular expression to match.
value : object
Replacement object.
inplace : bool, default False
Perform inplace modification.
regex : bool, default False
If true, perform regular expression substitution.
convert : bool, default True
If true, try to coerce any object types to better types.
mask : array-like of bool, optional
True indicate corresponding element is ignored.
Returns
-------
A new block if there is anything to replace or the original block.
"""
if mask.any():
if not regex:
self = self.coerce_to_target_dtype(value)
return self.putmask(mask, value, inplace=inplace)
else:
return self._replace_single(
to_replace,
value,
inplace=inplace,
regex=regex,
convert=convert,
mask=mask,
)
return self
class NonConsolidatableMixIn:
""" hold methods for the nonconsolidatable blocks """
_can_consolidate = False
_verify_integrity = False
_validate_ndim = False
def __init__(self, values, placement, ndim=None):
"""Initialize a non-consolidatable block.
'ndim' may be inferred from 'placement'.
This will call continue to call __init__ for the other base
classes mixed in with this Mixin.
"""
# Placement must be converted to BlockPlacement so that we can check
# its length
if not isinstance(placement, libinternals.BlockPlacement):
placement = libinternals.BlockPlacement(placement)
# Maybe infer ndim from placement
if ndim is None:
if len(placement) != 1:
ndim = 1
else:
ndim = 2
super().__init__(values, placement, ndim=ndim)
@property
def shape(self):
if self.ndim == 1:
return ((len(self.values)),)
return (len(self.mgr_locs), len(self.values))
def iget(self, col):
if self.ndim == 2 and isinstance(col, tuple):
col, loc = col
if not com.is_null_slice(col) and col != 0:
raise IndexError("{0} only contains one item".format(self))
elif isinstance(col, slice):
if col != slice(None):
raise NotImplementedError(col)
return self.values[[loc]]
return self.values[loc]
else:
if col != 0:
raise IndexError("{0} only contains one item".format(self))
return self.values
def should_store(self, value):
return isinstance(value, self._holder)
def set(self, locs, values, check=False):
assert locs.tolist() == [0]
self.values = values
def putmask(self, mask, new, align=True, inplace=False, axis=0, transpose=False):
"""
putmask the data to the block; we must be a single block and not
generate other blocks
return the resulting block
Parameters
----------
mask : the condition to respect
new : a ndarray/object
align : boolean, perform alignment on other/cond, default is True
inplace : perform inplace modification, default is False
Returns
-------
a new block, the result of the putmask
"""
inplace = validate_bool_kwarg(inplace, "inplace")
# use block's copy logic.
# .values may be an Index which does shallow copy by default
new_values = self.values if inplace else self.copy().values
if isinstance(new, np.ndarray) and len(new) == len(mask):
new = new[mask]
mask = _safe_reshape(mask, new_values.shape)
new_values[mask] = new
return [self.make_block(values=new_values)]
def _get_unstack_items(self, unstacker, new_columns):
"""
Get the placement, values, and mask for a Block unstack.
This is shared between ObjectBlock and ExtensionBlock. They
differ in that ObjectBlock passes the values, while ExtensionBlock
passes the dummy ndarray of positions to be used by a take
later.
Parameters
----------
unstacker : pandas.core.reshape.reshape._Unstacker
new_columns : Index
All columns of the unstacked BlockManager.
Returns
-------
new_placement : ndarray[int]
The placement of the new columns in `new_columns`.
new_values : Union[ndarray, ExtensionArray]
The first return value from _Unstacker.get_new_values.
mask : ndarray[bool]
The second return value from _Unstacker.get_new_values.
"""
# shared with ExtensionBlock
new_items = unstacker.get_new_columns()
new_placement = new_columns.get_indexer(new_items)
new_values, mask = unstacker.get_new_values()
mask = mask.any(0)
return new_placement, new_values, mask
class ExtensionBlock(NonConsolidatableMixIn, Block):
"""Block for holding extension types.
Notes
-----
This holds all 3rd-party extension array types. It's also the immediate
parent class for our internal extension types' blocks, CategoricalBlock.
ExtensionArrays are limited to 1-D.
"""
is_extension = True
def __init__(self, values, placement, ndim=None):
values = self._maybe_coerce_values(values)
super().__init__(values, placement, ndim)
def _maybe_coerce_values(self, values):
"""
Unbox to an extension array.
This will unbox an ExtensionArray stored in an Index or Series.
ExtensionArrays pass through. No dtype coercion is done.
Parameters
----------
values : Index, Series, ExtensionArray
Returns
-------
ExtensionArray
"""
return extract_array(values)
@property
def _holder(self):
# For extension blocks, the holder is values-dependent.
return type(self.values)
@property
def fill_value(self):
# Used in reindex_indexer
return self.values.dtype.na_value
@property
def _can_hold_na(self):
# The default ExtensionArray._can_hold_na is True
return self._holder._can_hold_na
@property
def is_view(self):
"""Extension arrays are never treated as views."""
return False
@property
def is_numeric(self):
return self.values.dtype._is_numeric
def setitem(self, indexer, value):
"""Set the value inplace, returning a same-typed block.
This differs from Block.setitem by not allowing setitem to change
the dtype of the Block.
Parameters
----------
indexer : tuple, list-like, array-like, slice
The subset of self.values to set
value : object
The value being set
Returns
-------
Block
Notes
-----
`indexer` is a direct slice/positional indexer. `value` must
be a compatible shape.
"""
if isinstance(indexer, tuple):
# we are always 1-D
indexer = indexer[0]
check_setitem_lengths(indexer, value, self.values)
self.values[indexer] = value
return self
def get_values(self, dtype=None):
# ExtensionArrays must be iterable, so this works.
values = np.asarray(self.values)
if values.ndim == self.ndim - 1:
values = values.reshape((1,) + values.shape)
return values
def to_dense(self):
return np.asarray(self.values)
def to_native_types(self, slicer=None, na_rep="nan", quoting=None, **kwargs):
"""override to use ExtensionArray astype for the conversion"""
values = self.values
if slicer is not None:
values = values[slicer]
mask = isna(values)
try:
values = values.astype(str)
values[mask] = na_rep
except Exception:
# eg SparseArray does not support setitem, needs to be converted to ndarray
return super().to_native_types(slicer, na_rep, quoting, **kwargs)
# we are expected to return a 2-d ndarray
return values.reshape(1, len(values))
def take_nd(self, indexer, axis=0, new_mgr_locs=None, fill_tuple=None):
"""
Take values according to indexer and return them as a block.
"""
if fill_tuple is None:
fill_value = None
else:
fill_value = fill_tuple[0]
# axis doesn't matter; we are really a single-dim object
# but are passed the axis depending on the calling routing
# if its REALLY axis 0, then this will be a reindex and not a take
new_values = self.values.take(indexer, fill_value=fill_value, allow_fill=True)
# Called from three places in managers, all of which satisfy
# this assertion
assert not (self.ndim == 1 and new_mgr_locs is None)
if new_mgr_locs is None:
new_mgr_locs = self.mgr_locs
return self.make_block_same_class(new_values, new_mgr_locs)
def _can_hold_element(self, element: Any) -> bool:
# XXX: We may need to think about pushing this onto the array.
# We're doing the same as CategoricalBlock here.
return True
def _slice(self, slicer):
""" return a slice of my values """
# slice the category
# return same dims as we currently have
if isinstance(slicer, tuple) and len(slicer) == 2:
if not com.is_null_slice(slicer[0]):
raise AssertionError("invalid slicing for a 1-ndim categorical")
slicer = slicer[1]
return self.values[slicer]
def concat_same_type(self, to_concat, placement=None):
"""
Concatenate list of single blocks of the same type.
"""
values = self._holder._concat_same_type([blk.values for blk in to_concat])
placement = placement or slice(0, len(values), 1)
return self.make_block_same_class(values, ndim=self.ndim, placement=placement)
def fillna(self, value, limit=None, inplace=False, downcast=None):
values = self.values if inplace else self.values.copy()
values = values.fillna(value=value, limit=limit)
return [
self.make_block_same_class(
values=values, placement=self.mgr_locs, ndim=self.ndim
)
]
def interpolate(
self, method="pad", axis=0, inplace=False, limit=None, fill_value=None, **kwargs
):
values = self.values if inplace else self.values.copy()
return self.make_block_same_class(
values=values.fillna(value=fill_value, method=method, limit=limit),
placement=self.mgr_locs,
)
def shift(
self,
periods: int,
axis: libinternals.BlockPlacement = 0,
fill_value: Any = None,
) -> List["ExtensionBlock"]:
"""
Shift the block by `periods`.
Dispatches to underlying ExtensionArray and re-boxes in an
ExtensionBlock.
"""
return [
self.make_block_same_class(
self.values.shift(periods=periods, fill_value=fill_value),
placement=self.mgr_locs,
ndim=self.ndim,
)
]
def where(
self,
other,
cond,
align=True,
errors="raise",
try_cast: bool = False,
axis: int = 0,
) -> List["Block"]:
if isinstance(other, ABCDataFrame):
# ExtensionArrays are 1-D, so if we get here then
# `other` should be a DataFrame with a single column.
assert other.shape[1] == 1
other = other.iloc[:, 0]
other = extract_array(other, extract_numpy=True)
if isinstance(cond, ABCDataFrame):
assert cond.shape[1] == 1
cond = cond.iloc[:, 0]
cond = extract_array(cond, extract_numpy=True)
if lib.is_scalar(other) and isna(other):
# The default `other` for Series / Frame is np.nan
# we want to replace that with the correct NA value
# for the type
other = self.dtype.na_value
if is_sparse(self.values):
# TODO(SparseArray.__setitem__): remove this if condition
# We need to re-infer the type of the data after doing the
# where, for cases where the subtypes don't match
dtype = None
else:
dtype = self.dtype
result = self.values.copy()
icond = ~cond
if lib.is_scalar(other):
set_other = other
else:
set_other = other[icond]
try:
result[icond] = set_other
except (NotImplementedError, TypeError):
# NotImplementedError for class not implementing `__setitem__`
# TypeError for SparseArray, which implements just to raise
# a TypeError
result = self._holder._from_sequence(
np.where(cond, self.values, other), dtype=dtype
)
return [self.make_block_same_class(result, placement=self.mgr_locs)]
@property
def _ftype(self):
return getattr(self.values, "_pandas_ftype", Block._ftype)
def _unstack(self, unstacker_func, new_columns, n_rows, fill_value):
# ExtensionArray-safe unstack.
# We override ObjectBlock._unstack, which unstacks directly on the
# values of the array. For EA-backed blocks, this would require
# converting to a 2-D ndarray of objects.
# Instead, we unstack an ndarray of integer positions, followed by
# a `take` on the actual values.
dummy_arr = np.arange(n_rows)
dummy_unstacker = functools.partial(unstacker_func, fill_value=-1)
unstacker = dummy_unstacker(dummy_arr)
new_placement, new_values, mask = self._get_unstack_items(
unstacker, new_columns
)
blocks = [
self.make_block_same_class(
self.values.take(indices, allow_fill=True, fill_value=fill_value),
[place],
)
for indices, place in zip(new_values.T, new_placement)
]
return blocks, mask
class ObjectValuesExtensionBlock(ExtensionBlock):
"""
Block providing backwards-compatibility for `.values`.
Used by PeriodArray and IntervalArray to ensure that
Series[T].values is an ndarray of objects.
"""
def external_values(self, dtype=None):
return self.values.astype(object)
class NumericBlock(Block):
__slots__ = ()
is_numeric = True
_can_hold_na = True
class FloatOrComplexBlock(NumericBlock):
__slots__ = ()
def equals(self, other) -> bool:
if self.dtype != other.dtype or self.shape != other.shape:
return False
left, right = self.values, other.values
return ((left == right) | (np.isnan(left) & np.isnan(right))).all()
class FloatBlock(FloatOrComplexBlock):
__slots__ = ()
is_float = True
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return issubclass(tipo.type, (np.floating, np.integer)) and not issubclass(
tipo.type, (np.datetime64, np.timedelta64)
)
return isinstance(
element, (float, int, np.floating, np.int_)
) and not isinstance(
element,
(bool, np.bool_, datetime, timedelta, np.datetime64, np.timedelta64),
)
def to_native_types(
self,
slicer=None,
na_rep="",
float_format=None,
decimal=".",
quoting=None,
**kwargs,
):
""" convert to our native types format, slicing if desired """
values = self.values
if slicer is not None:
values = values[:, slicer]
# see gh-13418: no special formatting is desired at the
# output (important for appropriate 'quoting' behaviour),
# so do not pass it through the FloatArrayFormatter
if float_format is None and decimal == ".":
mask = isna(values)
if not quoting:
values = values.astype(str)
else:
values = np.array(values, dtype="object")
values[mask] = na_rep
return values
from pandas.io.formats.format import FloatArrayFormatter
formatter = FloatArrayFormatter(
values,
na_rep=na_rep,
float_format=float_format,
decimal=decimal,
quoting=quoting,
fixed_width=False,
)
return formatter.get_result_as_array()
def should_store(self, value):
# when inserting a column should not coerce integers to floats
# unnecessarily
return issubclass(value.dtype.type, np.floating) and value.dtype == self.dtype
class ComplexBlock(FloatOrComplexBlock):
__slots__ = ()
is_complex = True
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return issubclass(tipo.type, (np.floating, np.integer, np.complexfloating))
return isinstance(
element, (float, int, complex, np.float_, np.int_)
) and not isinstance(element, (bool, np.bool_))
def should_store(self, value):
return issubclass(value.dtype.type, np.complexfloating)
class IntBlock(NumericBlock):
__slots__ = ()
is_integer = True
_can_hold_na = False
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return (
issubclass(tipo.type, np.integer)
and not issubclass(tipo.type, (np.datetime64, np.timedelta64))
and self.dtype.itemsize >= tipo.itemsize
)
return is_integer(element)
def should_store(self, value):
return is_integer_dtype(value) and value.dtype == self.dtype
class DatetimeLikeBlockMixin:
"""Mixin class for DatetimeBlock, DatetimeTZBlock, and TimedeltaBlock."""
@property
def _holder(self):
return DatetimeArray
@property
def fill_value(self):
return np.datetime64("NaT", "ns")
def get_values(self, dtype=None):
"""
return object dtype as boxed values, such as Timestamps/Timedelta
"""
if is_object_dtype(dtype):
values = self.values.ravel()
result = self._holder(values).astype(object)
return result.reshape(self.values.shape)
return self.values
class DatetimeBlock(DatetimeLikeBlockMixin, Block):
__slots__ = ()
is_datetime = True
def __init__(self, values, placement, ndim=None):
values = self._maybe_coerce_values(values)
super().__init__(values, placement=placement, ndim=ndim)
@property
def _can_hold_na(self):
return True
def _maybe_coerce_values(self, values):
"""
Input validation for values passed to __init__. Ensure that
we have datetime64ns, coercing if necessary.
Parameters
----------
values : array-like
Must be convertible to datetime64
Returns
-------
values : ndarray[datetime64ns]
Overridden by DatetimeTZBlock.
"""
if values.dtype != _NS_DTYPE:
values = conversion.ensure_datetime64ns(values)
if isinstance(values, DatetimeArray):
values = values._data
assert isinstance(values, np.ndarray), type(values)
return values
def _astype(self, dtype, **kwargs):
"""
these automatically copy, so copy=True has no effect
raise on an except if raise == True
"""
dtype = pandas_dtype(dtype)
# if we are passed a datetime64[ns, tz]
if is_datetime64tz_dtype(dtype):
values = self.values
if getattr(values, "tz", None) is None:
values = DatetimeArray(values).tz_localize("UTC")
values = values.tz_convert(dtype.tz)
return self.make_block(values)
# delegate
return super()._astype(dtype=dtype, **kwargs)
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
if self.is_datetimetz:
# require exact match, since non-nano does not exist
return is_dtype_equal(tipo, self.dtype) or is_valid_nat_for_dtype(
element, self.dtype
)
# GH#27419 if we get a non-nano datetime64 object
return is_datetime64_dtype(tipo)
elif element is NaT:
return True
elif isinstance(element, datetime):
if self.is_datetimetz:
return tz_compare(element.tzinfo, self.dtype.tz)
return element.tzinfo is None
return is_valid_nat_for_dtype(element, self.dtype)
def to_native_types(
self, slicer=None, na_rep=None, date_format=None, quoting=None, **kwargs
):
""" convert to our native types format, slicing if desired """
values = self.values
i8values = self.values.view("i8")
if slicer is not None:
values = values[..., slicer]
i8values = i8values[..., slicer]
from pandas.io.formats.format import _get_format_datetime64_from_values
fmt = _get_format_datetime64_from_values(values, date_format)
result = tslib.format_array_from_datetime(
i8values.ravel(),
tz=getattr(self.values, "tz", None),
format=fmt,
na_rep=na_rep,
).reshape(i8values.shape)
return np.atleast_2d(result)
def should_store(self, value):
return (
issubclass(value.dtype.type, np.datetime64)
and not is_datetime64tz_dtype(value)
and not is_extension_array_dtype(value)
)
def set(self, locs, values):
"""
Modify Block in-place with new item value
Returns
-------
None
"""
values = conversion.ensure_datetime64ns(values, copy=False)
self.values[locs] = values
def external_values(self):
return np.asarray(self.values.astype("datetime64[ns]", copy=False))
class DatetimeTZBlock(ExtensionBlock, DatetimeBlock):
""" implement a datetime64 block with a tz attribute """
__slots__ = ()
is_datetimetz = True
is_extension = True
_can_hold_element = DatetimeBlock._can_hold_element
to_native_types = DatetimeBlock.to_native_types
fill_value = np.datetime64("NaT", "ns")
@property
def _holder(self):
return DatetimeArray
def _maybe_coerce_values(self, values):
"""Input validation for values passed to __init__. Ensure that
we have datetime64TZ, coercing if necessary.
Parameters
----------
values : array-like
Must be convertible to datetime64
Returns
-------
values : DatetimeArray
"""
if not isinstance(values, self._holder):
values = self._holder(values)
if values.tz is None:
raise ValueError("cannot create a DatetimeTZBlock without a tz")
return values
@property
def is_view(self):
""" return a boolean if I am possibly a view """
# check the ndarray values of the DatetimeIndex values
return self.values._data.base is not None
def get_values(self, dtype=None):
"""
Returns an ndarray of values.
Parameters
----------
dtype : np.dtype
Only `object`-like dtypes are respected here (not sure
why).
Returns
-------
values : ndarray
When ``dtype=object``, then and object-dtype ndarray of
boxed values is returned. Otherwise, an M8[ns] ndarray
is returned.
DatetimeArray is always 1-d. ``get_values`` will reshape
the return value to be the same dimensionality as the
block.
"""
values = self.values
if is_object_dtype(dtype):
values = values.astype(object)
values = np.asarray(values)
if self.ndim == 2:
# Ensure that our shape is correct for DataFrame.
# ExtensionArrays are always 1-D, even in a DataFrame when
# the analogous NumPy-backed column would be a 2-D ndarray.
values = values.reshape(1, -1)
return values
def to_dense(self):
# we request M8[ns] dtype here, even though it discards tzinfo,
# as lots of code (e.g. anything using values_from_object)
# expects that behavior.
return np.asarray(self.values, dtype=_NS_DTYPE)
def _slice(self, slicer):
""" return a slice of my values """
if isinstance(slicer, tuple):
col, loc = slicer
if not com.is_null_slice(col) and col != 0:
raise IndexError("{0} only contains one item".format(self))
return self.values[loc]
return self.values[slicer]
def diff(self, n: int, axis: int = 0) -> List["Block"]:
"""
1st discrete difference.
Parameters
----------
n : int
Number of periods to diff.
axis : int, default 0
Axis to diff upon.
Returns
-------
A list with a new TimeDeltaBlock.
Notes
-----
The arguments here are mimicking shift so they are called correctly
by apply.
"""
if axis == 0:
# Cannot currently calculate diff across multiple blocks since this
# function is invoked via apply
raise NotImplementedError
new_values = (self.values - self.shift(n, axis=axis)[0].values).asi8
# Reshape the new_values like how algos.diff does for timedelta data
new_values = new_values.reshape(1, len(new_values))
new_values = new_values.astype("timedelta64[ns]")
return [TimeDeltaBlock(new_values, placement=self.mgr_locs.indexer)]
def concat_same_type(self, to_concat, placement=None):
# need to handle concat([tz1, tz2]) here, since DatetimeArray
# only handles cases where all the tzs are the same.
# Instead of placing the condition here, it could also go into the
# is_uniform_join_units check, but I'm not sure what is better.
if len({x.dtype for x in to_concat}) > 1:
values = concat_datetime([x.values for x in to_concat])
placement = placement or slice(0, len(values), 1)
if self.ndim > 1:
values = np.atleast_2d(values)
return ObjectBlock(values, ndim=self.ndim, placement=placement)
return super().concat_same_type(to_concat, placement)
def fillna(self, value, limit=None, inplace=False, downcast=None):
# We support filling a DatetimeTZ with a `value` whose timezone
# is different by coercing to object.
if self._can_hold_element(value):
return super().fillna(value, limit, inplace, downcast)
# different timezones, or a non-tz
return self.astype(object).fillna(
value, limit=limit, inplace=inplace, downcast=downcast
)
def setitem(self, indexer, value):
# https://github.com/pandas-dev/pandas/issues/24020
# Need a dedicated setitem until #24020 (type promotion in setitem
# for extension arrays) is designed and implemented.
if self._can_hold_element(value) or (
isinstance(indexer, np.ndarray) and indexer.size == 0
):
return super().setitem(indexer, value)
obj_vals = self.values.astype(object)
newb = make_block(
obj_vals, placement=self.mgr_locs, klass=ObjectBlock, ndim=self.ndim
)
return newb.setitem(indexer, value)
def equals(self, other) -> bool:
# override for significant performance improvement
if self.dtype != other.dtype or self.shape != other.shape:
return False
return (self.values.view("i8") == other.values.view("i8")).all()
def quantile(self, qs, interpolation="linear", axis=0):
naive = self.values.view("M8[ns]")
# kludge for 2D block with 1D values
naive = naive.reshape(self.shape)
blk = self.make_block(naive)
res_blk = blk.quantile(qs, interpolation=interpolation, axis=axis)
# ravel is kludge for 2D block with 1D values, assumes column-like
aware = self._holder(res_blk.values.ravel(), dtype=self.dtype)
return self.make_block_same_class(aware, ndim=res_blk.ndim)
class TimeDeltaBlock(DatetimeLikeBlockMixin, IntBlock):
__slots__ = ()
is_timedelta = True
_can_hold_na = True
is_numeric = False
fill_value = np.timedelta64("NaT", "ns")
def __init__(self, values, placement, ndim=None):
if values.dtype != _TD_DTYPE:
values = conversion.ensure_timedelta64ns(values)
if isinstance(values, TimedeltaArray):
values = values._data
assert isinstance(values, np.ndarray), type(values)
super().__init__(values, placement=placement, ndim=ndim)
@property
def _holder(self):
return TimedeltaArray
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return issubclass(tipo.type, np.timedelta64)
elif element is NaT:
return True
elif isinstance(element, (timedelta, np.timedelta64)):
return True
return is_valid_nat_for_dtype(element, self.dtype)
def fillna(self, value, **kwargs):
# allow filling with integers to be
# interpreted as nanoseconds
if is_integer(value):
# Deprecation GH#24694, GH#19233
warnings.warn(
"Passing integers to fillna is deprecated, will "
"raise a TypeError in a future version. To retain "
"the old behavior, pass pd.Timedelta(seconds=n) "
"instead.",
FutureWarning,
stacklevel=6,
)
value = Timedelta(value, unit="s")
return super().fillna(value, **kwargs)
def should_store(self, value):
return issubclass(
value.dtype.type, np.timedelta64
) and not is_extension_array_dtype(value)
def to_native_types(self, slicer=None, na_rep=None, quoting=None, **kwargs):
""" convert to our native types format, slicing if desired """
values = self.values
if slicer is not None:
values = values[:, slicer]
mask = isna(values)
rvalues = np.empty(values.shape, dtype=object)
if na_rep is None:
na_rep = "NaT"
rvalues[mask] = na_rep
imask = (~mask).ravel()
# FIXME:
# should use the formats.format.Timedelta64Formatter here
# to figure what format to pass to the Timedelta
# e.g. to not show the decimals say
rvalues.flat[imask] = np.array(
[Timedelta(val)._repr_base(format="all") for val in values.ravel()[imask]],
dtype=object,
)
return rvalues
def external_values(self, dtype=None):
return np.asarray(self.values.astype("timedelta64[ns]", copy=False))
class BoolBlock(NumericBlock):
__slots__ = ()
is_bool = True
_can_hold_na = False
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return issubclass(tipo.type, np.bool_)
return isinstance(element, (bool, np.bool_))
def should_store(self, value):
return issubclass(value.dtype.type, np.bool_) and not is_extension_array_dtype(
value
)
def replace(
self, to_replace, value, inplace=False, filter=None, regex=False, convert=True
):
inplace = validate_bool_kwarg(inplace, "inplace")
to_replace_values = np.atleast_1d(to_replace)
if not np.can_cast(to_replace_values, bool):
return self
return super().replace(
to_replace,
value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
class ObjectBlock(Block):
__slots__ = ()
is_object = True
_can_hold_na = True
def __init__(self, values, placement=None, ndim=2):
if issubclass(values.dtype.type, str):
values = np.array(values, dtype=object)
super().__init__(values, ndim=ndim, placement=placement)
@property
def is_bool(self):
""" we can be a bool if we have only bool values but are of type
object
"""
return lib.is_bool_array(self.values.ravel())
def convert(
self,
copy: bool = True,
datetime: bool = True,
numeric: bool = True,
timedelta: bool = True,
coerce: bool = False,
):
""" attempt to coerce any object types to better types return a copy of
the block (if copy = True) by definition we ARE an ObjectBlock!!!!!
can return multiple blocks!
"""
# operate column-by-column
def f(mask, val, idx):
shape = val.shape
values = soft_convert_objects(
val.ravel(),
datetime=datetime,
numeric=numeric,
timedelta=timedelta,
coerce=coerce,
copy=copy,
)
if isinstance(values, np.ndarray):
# TODO: allow EA once reshape is supported
values = values.reshape(shape)
values = _block_shape(values, ndim=self.ndim)
return values
if self.ndim == 2:
blocks = self.split_and_operate(None, f, False)
else:
values = f(None, self.values.ravel(), None)
blocks = [make_block(values, ndim=self.ndim, placement=self.mgr_locs)]
return blocks
def _maybe_downcast(self, blocks: List["Block"], downcast=None) -> List["Block"]:
if downcast is not None:
return blocks
# split and convert the blocks
return _extend_blocks([b.convert(datetime=True, numeric=False) for b in blocks])
def _can_hold_element(self, element: Any) -> bool:
return True
def should_store(self, value):
return not (
issubclass(
value.dtype.type,
(np.integer, np.floating, np.complexfloating, np.datetime64, np.bool_),
)
or is_extension_array_dtype(value)
)
def replace(
self, to_replace, value, inplace=False, filter=None, regex=False, convert=True
):
to_rep_is_list = is_list_like(to_replace)
value_is_list = is_list_like(value)
both_lists = to_rep_is_list and value_is_list
either_list = to_rep_is_list or value_is_list
result_blocks = []
blocks = [self]
if not either_list and is_re(to_replace):
return self._replace_single(
to_replace,
value,
inplace=inplace,
filter=filter,
regex=True,
convert=convert,
)
elif not (either_list or regex):
return super().replace(
to_replace,
value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
elif both_lists:
for to_rep, v in zip(to_replace, value):
result_blocks = []
for b in blocks:
result = b._replace_single(
to_rep,
v,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
result_blocks = _extend_blocks(result, result_blocks)
blocks = result_blocks
return result_blocks
elif to_rep_is_list and regex:
for to_rep in to_replace:
result_blocks = []
for b in blocks:
result = b._replace_single(
to_rep,
value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
result_blocks = _extend_blocks(result, result_blocks)
blocks = result_blocks
return result_blocks
return self._replace_single(
to_replace,
value,
inplace=inplace,
filter=filter,
convert=convert,
regex=regex,
)
def _replace_single(
self,
to_replace,
value,
inplace=False,
filter=None,
regex=False,
convert=True,
mask=None,
):
"""
Replace elements by the given value.
Parameters
----------
to_replace : object or pattern
Scalar to replace or regular expression to match.
value : object
Replacement object.
inplace : bool, default False
Perform inplace modification.
filter : list, optional
regex : bool, default False
If true, perform regular expression substitution.
convert : bool, default True
If true, try to coerce any object types to better types.
mask : array-like of bool, optional
True indicate corresponding element is ignored.
Returns
-------
a new block, the result after replacing
"""
inplace = validate_bool_kwarg(inplace, "inplace")
# to_replace is regex compilable
to_rep_re = regex and is_re_compilable(to_replace)
# regex is regex compilable
regex_re = is_re_compilable(regex)
# only one will survive
if to_rep_re and regex_re:
raise AssertionError(
"only one of to_replace and regex can be regex compilable"
)
# if regex was passed as something that can be a regex (rather than a
# boolean)
if regex_re:
to_replace = regex
regex = regex_re or to_rep_re
# try to get the pattern attribute (compiled re) or it's a string
if is_re(to_replace):
pattern = to_replace.pattern
else:
pattern = to_replace
# if the pattern is not empty and to_replace is either a string or a
# regex
if regex and pattern:
rx = re.compile(to_replace)
else:
# if the thing to replace is not a string or compiled regex call
# the superclass method -> to_replace is some kind of object
return super().replace(
to_replace, value, inplace=inplace, filter=filter, regex=regex
)
new_values = self.values if inplace else self.values.copy()
# deal with replacing values with objects (strings) that match but
# whose replacement is not a string (numeric, nan, object)
if isna(value) or not isinstance(value, str):
def re_replacer(s):
if is_re(rx) and isinstance(s, str):
return value if rx.search(s) is not None else s
else:
return s
else:
# value is guaranteed to be a string here, s can be either a string
# or null if it's null it gets returned
def re_replacer(s):
if is_re(rx) and isinstance(s, str):
return rx.sub(value, s)
else:
return s
f = np.vectorize(re_replacer, otypes=[self.dtype])
if filter is None:
filt = slice(None)
else:
filt = self.mgr_locs.isin(filter).nonzero()[0]
if mask is None:
new_values[filt] = f(new_values[filt])
else:
new_values[filt][mask] = f(new_values[filt][mask])
# convert
block = self.make_block(new_values)
if convert:
block = block.convert(numeric=False)
return block
def _replace_coerce(
self, to_replace, value, inplace=True, regex=False, convert=False, mask=None
):
"""
Replace value corresponding to the given boolean array with another
value.
Parameters
----------
to_replace : object or pattern
Scalar to replace or regular expression to match.
value : object
Replacement object.
inplace : bool, default False
Perform inplace modification.
regex : bool, default False
If true, perform regular expression substitution.
convert : bool, default True
If true, try to coerce any object types to better types.
mask : array-like of bool, optional
True indicate corresponding element is ignored.
Returns
-------
A new block if there is anything to replace or the original block.
"""
if mask.any():
block = super()._replace_coerce(
to_replace=to_replace,
value=value,
inplace=inplace,
regex=regex,
convert=convert,
mask=mask,
)
if convert:
block = [b.convert(numeric=False, copy=True) for b in block]
return block
if convert:
return [self.convert(numeric=False, copy=True)]
return self
class CategoricalBlock(ExtensionBlock):
__slots__ = ()
is_categorical = True
_verify_integrity = True
_can_hold_na = True
_concatenator = staticmethod(concat_categorical)
def __init__(self, values, placement, ndim=None):
# coerce to categorical if we can
values = extract_array(values)
assert isinstance(values, Categorical), type(values)
super().__init__(values, placement=placement, ndim=ndim)
@property
def _holder(self):
return Categorical
@property
def array_dtype(self):
""" the dtype to return if I want to construct this block as an
array
"""
return np.object_
def to_dense(self):
# Categorical.get_values returns a DatetimeIndex for datetime
# categories, so we can't simply use `np.asarray(self.values)` like
# other types.
return self.values._internal_get_values()
def to_native_types(self, slicer=None, na_rep="", quoting=None, **kwargs):
""" convert to our native types format, slicing if desired """
values = self.values
if slicer is not None:
# Categorical is always one dimension
values = values[slicer]
mask = isna(values)
values = np.array(values, dtype="object")
values[mask] = na_rep
# we are expected to return a 2-d ndarray
return values.reshape(1, len(values))
def concat_same_type(self, to_concat, placement=None):
"""
Concatenate list of single blocks of the same type.
Note that this CategoricalBlock._concat_same_type *may* not
return a CategoricalBlock. When the categories in `to_concat`
differ, this will return an object ndarray.
If / when we decide we don't like that behavior:
1. Change Categorical._concat_same_type to use union_categoricals
2. Delete this method.
"""
values = self._concatenator(
[blk.values for blk in to_concat], axis=self.ndim - 1
)
# not using self.make_block_same_class as values can be object dtype
return make_block(
values, placement=placement or slice(0, len(values), 1), ndim=self.ndim
)
def where(
self,
other,
cond,
align=True,
errors="raise",
try_cast: bool = False,
axis: int = 0,
) -> List["Block"]:
# TODO(CategoricalBlock.where):
# This can all be deleted in favor of ExtensionBlock.where once
# we enforce the deprecation.
object_msg = (
"Implicitly converting categorical to object-dtype ndarray. "
"One or more of the values in 'other' are not present in this "
"categorical's categories. A future version of pandas will raise "
"a ValueError when 'other' contains different categories.\n\n"
"To preserve the current behavior, add the new categories to "
"the categorical before calling 'where', or convert the "
"categorical to a different dtype."
)
try:
# Attempt to do preserve categorical dtype.
result = super().where(other, cond, align, errors, try_cast, axis)
except (TypeError, ValueError):
warnings.warn(object_msg, FutureWarning, stacklevel=6)
result = self.astype(object).where(
other, cond, align=align, errors=errors, try_cast=try_cast, axis=axis
)
return result
def replace(
self,
to_replace,
value,
inplace: bool = False,
filter=None,
regex: bool = False,
convert: bool = True,
):
inplace = validate_bool_kwarg(inplace, "inplace")
result = self if inplace else self.copy()
if filter is None: # replace was called on a series
result.values.replace(to_replace, value, inplace=True)
if convert:
return result.convert(numeric=False, copy=not inplace)
else:
return result
else: # replace was called on a DataFrame
if not isna(value):
result.values.add_categories(value, inplace=True)
return super(CategoricalBlock, result).replace(
to_replace, value, inplace, filter, regex, convert
)
# -----------------------------------------------------------------
# Constructor Helpers
def get_block_type(values, dtype=None):
"""
Find the appropriate Block subclass to use for the given values and dtype.
Parameters
----------
values : ndarray-like
dtype : numpy or pandas dtype
Returns
-------
cls : class, subclass of Block
"""
dtype = dtype or values.dtype
vtype = dtype.type
if is_sparse(dtype):
# Need this first(ish) so that Sparse[datetime] is sparse
cls = ExtensionBlock
elif is_categorical(values):
cls = CategoricalBlock
elif issubclass(vtype, np.datetime64):
assert not is_datetime64tz_dtype(values)
cls = DatetimeBlock
elif is_datetime64tz_dtype(values):
cls = DatetimeTZBlock
elif is_interval_dtype(dtype) or is_period_dtype(dtype):
cls = ObjectValuesExtensionBlock
elif is_extension_array_dtype(values):
cls = ExtensionBlock
elif issubclass(vtype, np.floating):
cls = FloatBlock
elif issubclass(vtype, np.timedelta64):
assert issubclass(vtype, np.integer)
cls = TimeDeltaBlock
elif issubclass(vtype, np.complexfloating):
cls = ComplexBlock
elif issubclass(vtype, np.integer):
cls = IntBlock
elif dtype == np.bool_:
cls = BoolBlock
else:
cls = ObjectBlock
return cls
def make_block(values, placement, klass=None, ndim=None, dtype=None, fastpath=None):
# Ensure that we don't allow PandasArray / PandasDtype in internals.
# For now, blocks should be backed by ndarrays when possible.
if isinstance(values, ABCPandasArray):
values = values.to_numpy()
if ndim and ndim > 1:
values = np.atleast_2d(values)
if isinstance(dtype, PandasDtype):
dtype = dtype.numpy_dtype
if fastpath is not None:
# GH#19265 pyarrow is passing this
warnings.warn(
"fastpath argument is deprecated, will be removed in a future release.",
FutureWarning,
)
if klass is None:
dtype = dtype or values.dtype
klass = get_block_type(values, dtype)
elif klass is DatetimeTZBlock and not is_datetime64tz_dtype(values):
# TODO: This is no longer hit internally; does it need to be retained
# for e.g. pyarrow?
values = DatetimeArray._simple_new(values, dtype=dtype)
return klass(values, ndim=ndim, placement=placement)
# -----------------------------------------------------------------
def _extend_blocks(result, blocks=None):
""" return a new extended blocks, givin the result """
from pandas.core.internals import BlockManager
if blocks is None:
blocks = []
if isinstance(result, list):
for r in result:
if isinstance(r, list):
blocks.extend(r)
else:
blocks.append(r)
elif isinstance(result, BlockManager):
blocks.extend(result.blocks)
else:
blocks.append(result)
return blocks
def _block_shape(values, ndim=1, shape=None):
""" guarantee the shape of the values to be at least 1 d """
if values.ndim < ndim:
if shape is None:
shape = values.shape
if not is_extension_array_dtype(values):
# TODO: https://github.com/pandas-dev/pandas/issues/23023
# block.shape is incorrect for "2D" ExtensionArrays
# We can't, and don't need to, reshape.
values = values.reshape(tuple((1,) + shape))
return values
def _merge_blocks(blocks, dtype=None, _can_consolidate=True):
if len(blocks) == 1:
return blocks[0]
if _can_consolidate:
if dtype is None:
if len({b.dtype for b in blocks}) != 1:
raise AssertionError("_merge_blocks are invalid!")
dtype = blocks[0].dtype
# FIXME: optimization potential in case all mgrs contain slices and
# combination of those slices is a slice, too.
new_mgr_locs = np.concatenate([b.mgr_locs.as_array for b in blocks])
new_values = np.vstack([b.values for b in blocks])
argsort = np.argsort(new_mgr_locs)
new_values = new_values[argsort]
new_mgr_locs = new_mgr_locs[argsort]
return make_block(new_values, placement=new_mgr_locs)
# no merge
return blocks
def _safe_reshape(arr, new_shape):
"""
If possible, reshape `arr` to have shape `new_shape`,
with a couple of exceptions (see gh-13012):
1) If `arr` is a ExtensionArray or Index, `arr` will be
returned as is.
2) If `arr` is a Series, the `_values` attribute will
be reshaped and returned.
Parameters
----------
arr : array-like, object to be reshaped
new_shape : int or tuple of ints, the new shape
"""
if isinstance(arr, ABCSeries):
arr = arr._values
if not isinstance(arr, ABCExtensionArray):
arr = arr.reshape(new_shape)
return arr
def _putmask_smart(v, mask, n):
"""
Return a new ndarray, try to preserve dtype if possible.
Parameters
----------
v : `values`, updated in-place (array like)
mask : np.ndarray
Applies to both sides (array like).
n : `new values` either scalar or an array like aligned with `values`
Returns
-------
values : ndarray with updated values
this *may* be a copy of the original
See Also
--------
ndarray.putmask
"""
# we cannot use np.asarray() here as we cannot have conversions
# that numpy does when numeric are mixed with strings
# n should be the length of the mask or a scalar here
if not is_list_like(n):
n = np.repeat(n, len(mask))
# see if we are only masking values that if putted
# will work in the current dtype
try:
nn = n[mask]
except TypeError:
# TypeError: only integer scalar arrays can be converted to a scalar index
pass
else:
# make sure that we have a nullable type
# if we have nulls
if not _isna_compat(v, nn[0]):
pass
elif not (is_float_dtype(nn.dtype) or is_integer_dtype(nn.dtype)):
# only compare integers/floats
pass
elif not (is_float_dtype(v.dtype) or is_integer_dtype(v.dtype)):
# only compare integers/floats
pass
else:
# we ignore ComplexWarning here
with warnings.catch_warnings(record=True):
warnings.simplefilter("ignore", np.ComplexWarning)
nn_at = nn.astype(v.dtype)
comp = nn == nn_at
if is_list_like(comp) and comp.all():
nv = v.copy()
nv[mask] = nn_at
return nv
n = np.asarray(n)
def _putmask_preserve(nv, n):
try:
nv[mask] = n[mask]
except (IndexError, ValueError):
nv[mask] = n
return nv
# preserves dtype if possible
if v.dtype.kind == n.dtype.kind:
return _putmask_preserve(v, n)
# change the dtype if needed
dtype, _ = maybe_promote(n.dtype)
if is_extension_array_dtype(v.dtype) and is_object_dtype(dtype):
v = v._internal_get_values(dtype)
else:
v = v.astype(dtype)
return _putmask_preserve(v, n)
| BugsInPy/BugsInPy/temp/projects/pandas/bug-121-fixed/pandas/pandas/core/internals/blocks.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-121-buggy/pandas/pandas/core/internals/blocks.py |
pandas-bug-63 | from typing import Hashable, List, Tuple, Union
import numpy as np
from pandas._libs.indexing import _NDFrameIndexerBase
from pandas._libs.lib import item_from_zerodim
from pandas.errors import AbstractMethodError
from pandas.util._decorators import Appender
from pandas.core.dtypes.common import (
is_float,
is_integer,
is_iterator,
is_list_like,
is_numeric_dtype,
is_scalar,
is_sequence,
)
from pandas.core.dtypes.concat import concat_compat
from pandas.core.dtypes.generic import ABCDataFrame, ABCMultiIndex, ABCSeries
from pandas.core.dtypes.missing import _infer_fill_value, isna
import pandas.core.common as com
from pandas.core.indexers import (
check_array_indexer,
is_list_like_indexer,
length_of_indexer,
)
from pandas.core.indexes.api import Index
from pandas.core.indexes.base import InvalidIndexError
# "null slice"
_NS = slice(None, None)
# the public IndexSlicerMaker
class _IndexSlice:
"""
Create an object to more easily perform multi-index slicing.
See Also
--------
MultiIndex.remove_unused_levels : New MultiIndex with no unused levels.
Notes
-----
See :ref:`Defined Levels <advanced.shown_levels>`
for further info on slicing a MultiIndex.
Examples
--------
>>> midx = pd.MultiIndex.from_product([['A0','A1'], ['B0','B1','B2','B3']])
>>> columns = ['foo', 'bar']
>>> dfmi = pd.DataFrame(np.arange(16).reshape((len(midx), len(columns))),
index=midx, columns=columns)
Using the default slice command:
>>> dfmi.loc[(slice(None), slice('B0', 'B1')), :]
foo bar
A0 B0 0 1
B1 2 3
A1 B0 8 9
B1 10 11
Using the IndexSlice class for a more intuitive command:
>>> idx = pd.IndexSlice
>>> dfmi.loc[idx[:, 'B0':'B1'], :]
foo bar
A0 B0 0 1
B1 2 3
A1 B0 8 9
B1 10 11
"""
def __getitem__(self, arg):
return arg
IndexSlice = _IndexSlice()
class IndexingError(Exception):
pass
class IndexingMixin:
"""Mixin for adding .loc/.iloc/.at/.iat to Datafames and Series.
"""
@property
def iloc(self) -> "_iLocIndexer":
"""
Purely integer-location based indexing for selection by position.
``.iloc[]`` is primarily integer position based (from ``0`` to
``length-1`` of the axis), but may also be used with a boolean
array.
Allowed inputs are:
- An integer, e.g. ``5``.
- A list or array of integers, e.g. ``[4, 3, 0]``.
- A slice object with ints, e.g. ``1:7``.
- A boolean array.
- A ``callable`` function with one argument (the calling Series or
DataFrame) and that returns valid output for indexing (one of the above).
This is useful in method chains, when you don't have a reference to the
calling object, but would like to base your selection on some value.
``.iloc`` will raise ``IndexError`` if a requested indexer is
out-of-bounds, except *slice* indexers which allow out-of-bounds
indexing (this conforms with python/numpy *slice* semantics).
See more at :ref:`Selection by Position <indexing.integer>`.
See Also
--------
DataFrame.iat : Fast integer location scalar accessor.
DataFrame.loc : Purely label-location based indexer for selection by label.
Series.iloc : Purely integer-location based indexing for
selection by position.
Examples
--------
>>> mydict = [{'a': 1, 'b': 2, 'c': 3, 'd': 4},
... {'a': 100, 'b': 200, 'c': 300, 'd': 400},
... {'a': 1000, 'b': 2000, 'c': 3000, 'd': 4000 }]
>>> df = pd.DataFrame(mydict)
>>> df
a b c d
0 1 2 3 4
1 100 200 300 400
2 1000 2000 3000 4000
**Indexing just the rows**
With a scalar integer.
>>> type(df.iloc[0])
<class 'pandas.core.series.Series'>
>>> df.iloc[0]
a 1
b 2
c 3
d 4
Name: 0, dtype: int64
With a list of integers.
>>> df.iloc[[0]]
a b c d
0 1 2 3 4
>>> type(df.iloc[[0]])
<class 'pandas.core.frame.DataFrame'>
>>> df.iloc[[0, 1]]
a b c d
0 1 2 3 4
1 100 200 300 400
With a `slice` object.
>>> df.iloc[:3]
a b c d
0 1 2 3 4
1 100 200 300 400
2 1000 2000 3000 4000
With a boolean mask the same length as the index.
>>> df.iloc[[True, False, True]]
a b c d
0 1 2 3 4
2 1000 2000 3000 4000
With a callable, useful in method chains. The `x` passed
to the ``lambda`` is the DataFrame being sliced. This selects
the rows whose index label even.
>>> df.iloc[lambda x: x.index % 2 == 0]
a b c d
0 1 2 3 4
2 1000 2000 3000 4000
**Indexing both axes**
You can mix the indexer types for the index and columns. Use ``:`` to
select the entire axis.
With scalar integers.
>>> df.iloc[0, 1]
2
With lists of integers.
>>> df.iloc[[0, 2], [1, 3]]
b d
0 2 4
2 2000 4000
With `slice` objects.
>>> df.iloc[1:3, 0:3]
a b c
1 100 200 300
2 1000 2000 3000
With a boolean array whose length matches the columns.
>>> df.iloc[:, [True, False, True, False]]
a c
0 1 3
1 100 300
2 1000 3000
With a callable function that expects the Series or DataFrame.
>>> df.iloc[:, lambda df: [0, 2]]
a c
0 1 3
1 100 300
2 1000 3000
"""
return _iLocIndexer("iloc", self)
@property
def loc(self) -> "_LocIndexer":
"""
Access a group of rows and columns by label(s) or a boolean array.
``.loc[]`` is primarily label based, but may also be used with a
boolean array.
Allowed inputs are:
- A single label, e.g. ``5`` or ``'a'``, (note that ``5`` is
interpreted as a *label* of the index, and **never** as an
integer position along the index).
- A list or array of labels, e.g. ``['a', 'b', 'c']``.
- A slice object with labels, e.g. ``'a':'f'``.
.. warning:: Note that contrary to usual python slices, **both** the
start and the stop are included
- A boolean array of the same length as the axis being sliced,
e.g. ``[True, False, True]``.
- A ``callable`` function with one argument (the calling Series or
DataFrame) and that returns valid output for indexing (one of the above)
See more at :ref:`Selection by Label <indexing.label>`
Raises
------
KeyError
If any items are not found.
See Also
--------
DataFrame.at : Access a single value for a row/column label pair.
DataFrame.iloc : Access group of rows and columns by integer position(s).
DataFrame.xs : Returns a cross-section (row(s) or column(s)) from the
Series/DataFrame.
Series.loc : Access group of values using labels.
Examples
--------
**Getting values**
>>> df = pd.DataFrame([[1, 2], [4, 5], [7, 8]],
... index=['cobra', 'viper', 'sidewinder'],
... columns=['max_speed', 'shield'])
>>> df
max_speed shield
cobra 1 2
viper 4 5
sidewinder 7 8
Single label. Note this returns the row as a Series.
>>> df.loc['viper']
max_speed 4
shield 5
Name: viper, dtype: int64
List of labels. Note using ``[[]]`` returns a DataFrame.
>>> df.loc[['viper', 'sidewinder']]
max_speed shield
viper 4 5
sidewinder 7 8
Single label for row and column
>>> df.loc['cobra', 'shield']
2
Slice with labels for row and single label for column. As mentioned
above, note that both the start and stop of the slice are included.
>>> df.loc['cobra':'viper', 'max_speed']
cobra 1
viper 4
Name: max_speed, dtype: int64
Boolean list with the same length as the row axis
>>> df.loc[[False, False, True]]
max_speed shield
sidewinder 7 8
Conditional that returns a boolean Series
>>> df.loc[df['shield'] > 6]
max_speed shield
sidewinder 7 8
Conditional that returns a boolean Series with column labels specified
>>> df.loc[df['shield'] > 6, ['max_speed']]
max_speed
sidewinder 7
Callable that returns a boolean Series
>>> df.loc[lambda df: df['shield'] == 8]
max_speed shield
sidewinder 7 8
**Setting values**
Set value for all items matching the list of labels
>>> df.loc[['viper', 'sidewinder'], ['shield']] = 50
>>> df
max_speed shield
cobra 1 2
viper 4 50
sidewinder 7 50
Set value for an entire row
>>> df.loc['cobra'] = 10
>>> df
max_speed shield
cobra 10 10
viper 4 50
sidewinder 7 50
Set value for an entire column
>>> df.loc[:, 'max_speed'] = 30
>>> df
max_speed shield
cobra 30 10
viper 30 50
sidewinder 30 50
Set value for rows matching callable condition
>>> df.loc[df['shield'] > 35] = 0
>>> df
max_speed shield
cobra 30 10
viper 0 0
sidewinder 0 0
**Getting values on a DataFrame with an index that has integer labels**
Another example using integers for the index
>>> df = pd.DataFrame([[1, 2], [4, 5], [7, 8]],
... index=[7, 8, 9], columns=['max_speed', 'shield'])
>>> df
max_speed shield
7 1 2
8 4 5
9 7 8
Slice with integer labels for rows. As mentioned above, note that both
the start and stop of the slice are included.
>>> df.loc[7:9]
max_speed shield
7 1 2
8 4 5
9 7 8
**Getting values with a MultiIndex**
A number of examples using a DataFrame with a MultiIndex
>>> tuples = [
... ('cobra', 'mark i'), ('cobra', 'mark ii'),
... ('sidewinder', 'mark i'), ('sidewinder', 'mark ii'),
... ('viper', 'mark ii'), ('viper', 'mark iii')
... ]
>>> index = pd.MultiIndex.from_tuples(tuples)
>>> values = [[12, 2], [0, 4], [10, 20],
... [1, 4], [7, 1], [16, 36]]
>>> df = pd.DataFrame(values, columns=['max_speed', 'shield'], index=index)
>>> df
max_speed shield
cobra mark i 12 2
mark ii 0 4
sidewinder mark i 10 20
mark ii 1 4
viper mark ii 7 1
mark iii 16 36
Single label. Note this returns a DataFrame with a single index.
>>> df.loc['cobra']
max_speed shield
mark i 12 2
mark ii 0 4
Single index tuple. Note this returns a Series.
>>> df.loc[('cobra', 'mark ii')]
max_speed 0
shield 4
Name: (cobra, mark ii), dtype: int64
Single label for row and column. Similar to passing in a tuple, this
returns a Series.
>>> df.loc['cobra', 'mark i']
max_speed 12
shield 2
Name: (cobra, mark i), dtype: int64
Single tuple. Note using ``[[]]`` returns a DataFrame.
>>> df.loc[[('cobra', 'mark ii')]]
max_speed shield
cobra mark ii 0 4
Single tuple for the index with a single label for the column
>>> df.loc[('cobra', 'mark i'), 'shield']
2
Slice from index tuple to single label
>>> df.loc[('cobra', 'mark i'):'viper']
max_speed shield
cobra mark i 12 2
mark ii 0 4
sidewinder mark i 10 20
mark ii 1 4
viper mark ii 7 1
mark iii 16 36
Slice from index tuple to index tuple
>>> df.loc[('cobra', 'mark i'):('viper', 'mark ii')]
max_speed shield
cobra mark i 12 2
mark ii 0 4
sidewinder mark i 10 20
mark ii 1 4
viper mark ii 7 1
"""
return _LocIndexer("loc", self)
@property
def at(self) -> "_AtIndexer":
"""
Access a single value for a row/column label pair.
Similar to ``loc``, in that both provide label-based lookups. Use
``at`` if you only need to get or set a single value in a DataFrame
or Series.
Raises
------
KeyError
If 'label' does not exist in DataFrame.
See Also
--------
DataFrame.iat : Access a single value for a row/column pair by integer
position.
DataFrame.loc : Access a group of rows and columns by label(s).
Series.at : Access a single value using a label.
Examples
--------
>>> df = pd.DataFrame([[0, 2, 3], [0, 4, 1], [10, 20, 30]],
... index=[4, 5, 6], columns=['A', 'B', 'C'])
>>> df
A B C
4 0 2 3
5 0 4 1
6 10 20 30
Get value at specified row/column pair
>>> df.at[4, 'B']
2
Set value at specified row/column pair
>>> df.at[4, 'B'] = 10
>>> df.at[4, 'B']
10
Get value within a Series
>>> df.loc[5].at['B']
4
"""
return _AtIndexer("at", self)
@property
def iat(self) -> "_iAtIndexer":
"""
Access a single value for a row/column pair by integer position.
Similar to ``iloc``, in that both provide integer-based lookups. Use
``iat`` if you only need to get or set a single value in a DataFrame
or Series.
Raises
------
IndexError
When integer position is out of bounds.
See Also
--------
DataFrame.at : Access a single value for a row/column label pair.
DataFrame.loc : Access a group of rows and columns by label(s).
DataFrame.iloc : Access a group of rows and columns by integer position(s).
Examples
--------
>>> df = pd.DataFrame([[0, 2, 3], [0, 4, 1], [10, 20, 30]],
... columns=['A', 'B', 'C'])
>>> df
A B C
0 0 2 3
1 0 4 1
2 10 20 30
Get value at specified row/column pair
>>> df.iat[1, 2]
1
Set value at specified row/column pair
>>> df.iat[1, 2] = 10
>>> df.iat[1, 2]
10
Get value within a series
>>> df.loc[0].iat[1]
2
"""
return _iAtIndexer("iat", self)
class _LocationIndexer(_NDFrameIndexerBase):
_valid_types: str
axis = None
def __call__(self, axis=None):
# we need to return a copy of ourselves
new_self = type(self)(self.name, self.obj)
if axis is not None:
axis = self.obj._get_axis_number(axis)
new_self.axis = axis
return new_self
def _get_label(self, label, axis: int):
if self.ndim == 1:
# for perf reasons we want to try _xs first
# as its basically direct indexing
# but will fail when the index is not present
# see GH5667
return self.obj._xs(label, axis=axis)
elif isinstance(label, tuple) and isinstance(label[axis], slice):
raise IndexingError("no slices here, handle elsewhere")
return self.obj._xs(label, axis=axis)
def _get_setitem_indexer(self, key):
if self.axis is not None:
return self._convert_tuple(key, is_setter=True)
ax = self.obj._get_axis(0)
if isinstance(ax, ABCMultiIndex) and self.name != "iloc":
try:
return ax.get_loc(key)
except (TypeError, KeyError, InvalidIndexError):
# TypeError e.g. passed a bool
pass
if isinstance(key, tuple):
try:
return self._convert_tuple(key, is_setter=True)
except IndexingError:
pass
if isinstance(key, range):
return list(key)
try:
return self._convert_to_indexer(key, axis=0, is_setter=True)
except TypeError as e:
# invalid indexer type vs 'other' indexing errors
if "cannot do" in str(e):
raise
raise IndexingError(key)
def __setitem__(self, key, value):
if isinstance(key, tuple):
key = tuple(com.apply_if_callable(x, self.obj) for x in key)
else:
key = com.apply_if_callable(key, self.obj)
indexer = self._get_setitem_indexer(key)
self._setitem_with_indexer(indexer, value)
def _validate_key(self, key, axis: int):
"""
Ensure that key is valid for current indexer.
Parameters
----------
key : scalar, slice or list-like
Key requested.
axis : int
Dimension on which the indexing is being made.
Raises
------
TypeError
If the key (or some element of it) has wrong type.
IndexError
If the key (or some element of it) is out of bounds.
KeyError
If the key was not found.
"""
raise AbstractMethodError(self)
def _has_valid_tuple(self, key: Tuple):
"""
Check the key for valid keys across my indexer.
"""
for i, k in enumerate(key):
if i >= self.ndim:
raise IndexingError("Too many indexers")
try:
self._validate_key(k, i)
except ValueError:
raise ValueError(
"Location based indexing can only have "
f"[{self._valid_types}] types"
)
def _is_nested_tuple_indexer(self, tup: Tuple) -> bool:
"""
Returns
-------
bool
"""
if any(isinstance(ax, ABCMultiIndex) for ax in self.obj.axes):
return any(is_nested_tuple(tup, ax) for ax in self.obj.axes)
return False
def _convert_tuple(self, key, is_setter: bool = False):
keyidx = []
if self.axis is not None:
axis = self.obj._get_axis_number(self.axis)
for i in range(self.ndim):
if i == axis:
keyidx.append(
self._convert_to_indexer(key, axis=axis, is_setter=is_setter)
)
else:
keyidx.append(slice(None))
else:
for i, k in enumerate(key):
if i >= self.ndim:
raise IndexingError("Too many indexers")
idx = self._convert_to_indexer(k, axis=i, is_setter=is_setter)
keyidx.append(idx)
return tuple(keyidx)
def _has_valid_setitem_indexer(self, indexer) -> bool:
return True
def _has_valid_positional_setitem_indexer(self, indexer) -> bool:
"""
Validate that a positional indexer cannot enlarge its target
will raise if needed, does not modify the indexer externally.
Returns
-------
bool
"""
if isinstance(indexer, dict):
raise IndexError(f"{self.name} cannot enlarge its target object")
else:
if not isinstance(indexer, tuple):
indexer = _tuplify(self.ndim, indexer)
for ax, i in zip(self.obj.axes, indexer):
if isinstance(i, slice):
# should check the stop slice?
pass
elif is_list_like_indexer(i):
# should check the elements?
pass
elif is_integer(i):
if i >= len(ax):
raise IndexError(
f"{self.name} cannot enlarge its target object"
)
elif isinstance(i, dict):
raise IndexError(f"{self.name} cannot enlarge its target object")
return True
def _setitem_with_indexer(self, indexer, value):
self._has_valid_setitem_indexer(indexer)
# also has the side effect of consolidating in-place
from pandas import Series
info_axis = self.obj._info_axis_number
# maybe partial set
take_split_path = self.obj._is_mixed_type
# if there is only one block/type, still have to take split path
# unless the block is one-dimensional or it can hold the value
if not take_split_path and self.obj._data.blocks:
(blk,) = self.obj._data.blocks
if 1 < blk.ndim: # in case of dict, keys are indices
val = list(value.values()) if isinstance(value, dict) else value
take_split_path = not blk._can_hold_element(val)
# if we have any multi-indexes that have non-trivial slices
# (not null slices) then we must take the split path, xref
# GH 10360, GH 27841
if isinstance(indexer, tuple) and len(indexer) == len(self.obj.axes):
for i, ax in zip(indexer, self.obj.axes):
if isinstance(ax, ABCMultiIndex) and not (
is_integer(i) or com.is_null_slice(i)
):
take_split_path = True
break
if isinstance(indexer, tuple):
nindexer = []
for i, idx in enumerate(indexer):
if isinstance(idx, dict):
# reindex the axis to the new value
# and set inplace
key, _ = convert_missing_indexer(idx)
# if this is the items axes, then take the main missing
# path first
# this correctly sets the dtype and avoids cache issues
# essentially this separates out the block that is needed
# to possibly be modified
if self.ndim > 1 and i == self.obj._info_axis_number:
# add the new item, and set the value
# must have all defined axes if we have a scalar
# or a list-like on the non-info axes if we have a
# list-like
len_non_info_axes = (
len(_ax) for _i, _ax in enumerate(self.obj.axes) if _i != i
)
if any(not l for l in len_non_info_axes):
if not is_list_like_indexer(value):
raise ValueError(
"cannot set a frame with no "
"defined index and a scalar"
)
self.obj[key] = value
return self.obj
# add a new item with the dtype setup
self.obj[key] = _infer_fill_value(value)
new_indexer = convert_from_missing_indexer_tuple(
indexer, self.obj.axes
)
self._setitem_with_indexer(new_indexer, value)
return self.obj
# reindex the axis
# make sure to clear the cache because we are
# just replacing the block manager here
# so the object is the same
index = self.obj._get_axis(i)
labels = index.insert(len(index), key)
self.obj._data = self.obj.reindex(labels, axis=i)._data
self.obj._maybe_update_cacher(clear=True)
self.obj._is_copy = None
nindexer.append(labels.get_loc(key))
else:
nindexer.append(idx)
indexer = tuple(nindexer)
else:
indexer, missing = convert_missing_indexer(indexer)
if missing:
return self._setitem_with_indexer_missing(indexer, value)
# set
item_labels = self.obj._get_axis(info_axis)
# align and set the values
if take_split_path:
# Above we only set take_split_path to True for 2D cases
assert self.ndim == 2
assert info_axis == 1
if not isinstance(indexer, tuple):
indexer = _tuplify(self.ndim, indexer)
if isinstance(value, ABCSeries):
value = self._align_series(indexer, value)
info_idx = indexer[info_axis]
if is_integer(info_idx):
info_idx = [info_idx]
labels = item_labels[info_idx]
# if we have a partial multiindex, then need to adjust the plane
# indexer here
if len(labels) == 1 and isinstance(
self.obj[labels[0]].axes[0], ABCMultiIndex
):
item = labels[0]
obj = self.obj[item]
index = obj.index
idx = indexer[:info_axis][0]
plane_indexer = tuple([idx]) + indexer[info_axis + 1 :]
lplane_indexer = length_of_indexer(plane_indexer[0], index)
# require that we are setting the right number of values that
# we are indexing
if (
is_list_like_indexer(value)
and np.iterable(value)
and lplane_indexer != len(value)
):
if len(obj[idx]) != len(value):
raise ValueError(
"cannot set using a multi-index "
"selection indexer with a different "
"length than the value"
)
# make sure we have an ndarray
value = getattr(value, "values", value).ravel()
# we can directly set the series here
# as we select a slice indexer on the mi
if isinstance(idx, slice):
idx = index._convert_slice_indexer(idx)
obj._consolidate_inplace()
obj = obj.copy()
obj._data = obj._data.setitem(indexer=tuple([idx]), value=value)
self.obj[item] = obj
return
# non-mi
else:
plane_indexer = indexer[:info_axis] + indexer[info_axis + 1 :]
plane_axis = self.obj.axes[:info_axis][0]
lplane_indexer = length_of_indexer(plane_indexer[0], plane_axis)
def setter(item, v):
s = self.obj[item]
pi = plane_indexer[0] if lplane_indexer == 1 else plane_indexer
# perform the equivalent of a setitem on the info axis
# as we have a null slice or a slice with full bounds
# which means essentially reassign to the columns of a
# multi-dim object
# GH6149 (null slice), GH10408 (full bounds)
if isinstance(pi, tuple) and all(
com.is_null_slice(idx) or com.is_full_slice(idx, len(self.obj))
for idx in pi
):
s = v
else:
# set the item, possibly having a dtype change
s._consolidate_inplace()
s = s.copy()
s._data = s._data.setitem(indexer=pi, value=v)
s._maybe_update_cacher(clear=True)
# reset the sliced object if unique
self.obj[item] = s
# we need an iterable, with a ndim of at least 1
# eg. don't pass through np.array(0)
if is_list_like_indexer(value) and getattr(value, "ndim", 1) > 0:
# we have an equal len Frame
if isinstance(value, ABCDataFrame):
sub_indexer = list(indexer)
multiindex_indexer = isinstance(labels, ABCMultiIndex)
for item in labels:
if item in value:
sub_indexer[info_axis] = item
v = self._align_series(
tuple(sub_indexer), value[item], multiindex_indexer
)
else:
v = np.nan
setter(item, v)
# we have an equal len ndarray/convertible to our labels
# hasattr first, to avoid coercing to ndarray without reason.
# But we may be relying on the ndarray coercion to check ndim.
# Why not just convert to an ndarray earlier on if needed?
elif np.ndim(value) == 2:
# note that this coerces the dtype if we are mixed
# GH 7551
value = np.array(value, dtype=object)
if len(labels) != value.shape[1]:
raise ValueError(
"Must have equal len keys and value "
"when setting with an ndarray"
)
for i, item in enumerate(labels):
# setting with a list, recoerces
setter(item, value[:, i].tolist())
# we have an equal len list/ndarray
elif _can_do_equal_len(
labels, value, plane_indexer, lplane_indexer, self.obj
):
setter(labels[0], value)
# per label values
else:
if len(labels) != len(value):
raise ValueError(
"Must have equal len keys and value "
"when setting with an iterable"
)
for item, v in zip(labels, value):
setter(item, v)
else:
# scalar
for item in labels:
setter(item, value)
else:
if isinstance(indexer, tuple):
indexer = maybe_convert_ix(*indexer)
# if we are setting on the info axis ONLY
# set using those methods to avoid block-splitting
# logic here
if (
len(indexer) > info_axis
and is_integer(indexer[info_axis])
and all(
com.is_null_slice(idx)
for i, idx in enumerate(indexer)
if i != info_axis
)
and item_labels.is_unique
):
self.obj[item_labels[indexer[info_axis]]] = value
return
if isinstance(value, (ABCSeries, dict)):
# TODO(EA): ExtensionBlock.setitem this causes issues with
# setting for extensionarrays that store dicts. Need to decide
# if it's worth supporting that.
value = self._align_series(indexer, Series(value))
elif isinstance(value, ABCDataFrame):
value = self._align_frame(indexer, value)
# check for chained assignment
self.obj._check_is_chained_assignment_possible()
# actually do the set
self.obj._consolidate_inplace()
self.obj._data = self.obj._data.setitem(indexer=indexer, value=value)
self.obj._maybe_update_cacher(clear=True)
def _setitem_with_indexer_missing(self, indexer, value):
"""
Insert new row(s) or column(s) into the Series or DataFrame.
"""
from pandas import Series
# reindex the axis to the new value
# and set inplace
if self.ndim == 1:
index = self.obj.index
new_index = index.insert(len(index), indexer)
# we have a coerced indexer, e.g. a float
# that matches in an Int64Index, so
# we will not create a duplicate index, rather
# index to that element
# e.g. 0.0 -> 0
# GH#12246
if index.is_unique:
new_indexer = index.get_indexer([new_index[-1]])
if (new_indexer != -1).any():
return self._setitem_with_indexer(new_indexer, value)
# this preserves dtype of the value
new_values = Series([value])._values
if len(self.obj._values):
# GH#22717 handle casting compatibility that np.concatenate
# does incorrectly
new_values = concat_compat([self.obj._values, new_values])
self.obj._data = self.obj._constructor(
new_values, index=new_index, name=self.obj.name
)._data
self.obj._maybe_update_cacher(clear=True)
return self.obj
elif self.ndim == 2:
if not len(self.obj.columns):
# no columns and scalar
raise ValueError("cannot set a frame with no defined columns")
if isinstance(value, ABCSeries):
# append a Series
value = value.reindex(index=self.obj.columns, copy=True)
value.name = indexer
else:
# a list-list
if is_list_like_indexer(value):
# must have conforming columns
if len(value) != len(self.obj.columns):
raise ValueError("cannot set a row with mismatched columns")
value = Series(value, index=self.obj.columns, name=indexer)
self.obj._data = self.obj.append(value)._data
self.obj._maybe_update_cacher(clear=True)
return self.obj
def _align_series(self, indexer, ser: ABCSeries, multiindex_indexer: bool = False):
"""
Parameters
----------
indexer : tuple, slice, scalar
Indexer used to get the locations that will be set to `ser`.
ser : pd.Series
Values to assign to the locations specified by `indexer`.
multiindex_indexer : boolean, optional
Defaults to False. Should be set to True if `indexer` was from
a `pd.MultiIndex`, to avoid unnecessary broadcasting.
Returns
-------
`np.array` of `ser` broadcast to the appropriate shape for assignment
to the locations selected by `indexer`
"""
if isinstance(indexer, (slice, np.ndarray, list, Index)):
indexer = tuple([indexer])
if isinstance(indexer, tuple):
# flatten np.ndarray indexers
def ravel(i):
return i.ravel() if isinstance(i, np.ndarray) else i
indexer = tuple(map(ravel, indexer))
aligners = [not com.is_null_slice(idx) for idx in indexer]
sum_aligners = sum(aligners)
single_aligner = sum_aligners == 1
is_frame = self.ndim == 2
obj = self.obj
# are we a single alignable value on a non-primary
# dim (e.g. panel: 1,2, or frame: 0) ?
# hence need to align to a single axis dimension
# rather that find all valid dims
# frame
if is_frame:
single_aligner = single_aligner and aligners[0]
# we have a frame, with multiple indexers on both axes; and a
# series, so need to broadcast (see GH5206)
if sum_aligners == self.ndim and all(is_sequence(_) for _ in indexer):
ser = ser.reindex(obj.axes[0][indexer[0]], copy=True)._values
# single indexer
if len(indexer) > 1 and not multiindex_indexer:
len_indexer = len(indexer[1])
ser = np.tile(ser, len_indexer).reshape(len_indexer, -1).T
return ser
for i, idx in enumerate(indexer):
ax = obj.axes[i]
# multiple aligners (or null slices)
if is_sequence(idx) or isinstance(idx, slice):
if single_aligner and com.is_null_slice(idx):
continue
new_ix = ax[idx]
if not is_list_like_indexer(new_ix):
new_ix = Index([new_ix])
else:
new_ix = Index(new_ix)
if ser.index.equals(new_ix) or not len(new_ix):
return ser._values.copy()
return ser.reindex(new_ix)._values
# 2 dims
elif single_aligner:
# reindex along index
ax = self.obj.axes[1]
if ser.index.equals(ax) or not len(ax):
return ser._values.copy()
return ser.reindex(ax)._values
elif is_scalar(indexer):
ax = self.obj._get_axis(1)
if ser.index.equals(ax):
return ser._values.copy()
return ser.reindex(ax)._values
raise ValueError("Incompatible indexer with Series")
def _align_frame(self, indexer, df: ABCDataFrame):
is_frame = self.ndim == 2
if isinstance(indexer, tuple):
idx, cols = None, None
sindexers = []
for i, ix in enumerate(indexer):
ax = self.obj.axes[i]
if is_sequence(ix) or isinstance(ix, slice):
if isinstance(ix, np.ndarray):
ix = ix.ravel()
if idx is None:
idx = ax[ix]
elif cols is None:
cols = ax[ix]
else:
break
else:
sindexers.append(i)
if idx is not None and cols is not None:
if df.index.equals(idx) and df.columns.equals(cols):
val = df.copy()._values
else:
val = df.reindex(idx, columns=cols)._values
return val
elif (isinstance(indexer, slice) or is_list_like_indexer(indexer)) and is_frame:
ax = self.obj.index[indexer]
if df.index.equals(ax):
val = df.copy()._values
else:
# we have a multi-index and are trying to align
# with a particular, level GH3738
if (
isinstance(ax, ABCMultiIndex)
and isinstance(df.index, ABCMultiIndex)
and ax.nlevels != df.index.nlevels
):
raise TypeError(
"cannot align on a multi-index with out "
"specifying the join levels"
)
val = df.reindex(index=ax)._values
return val
raise ValueError("Incompatible indexer with DataFrame")
def _getitem_tuple(self, tup: Tuple):
try:
return self._getitem_lowerdim(tup)
except IndexingError:
pass
# no multi-index, so validate all of the indexers
self._has_valid_tuple(tup)
# ugly hack for GH #836
if self._multi_take_opportunity(tup):
return self._multi_take(tup)
# no shortcut needed
retval = self.obj
for i, key in enumerate(tup):
if com.is_null_slice(key):
continue
retval = getattr(retval, self.name)._getitem_axis(key, axis=i)
return retval
def _multi_take_opportunity(self, tup: Tuple) -> bool:
"""
Check whether there is the possibility to use ``_multi_take``.
Currently the limit is that all axes being indexed, must be indexed with
list-likes.
Parameters
----------
tup : tuple
Tuple of indexers, one per axis.
Returns
-------
bool
Whether the current indexing,
can be passed through `_multi_take`.
"""
if not all(is_list_like_indexer(x) for x in tup):
return False
# just too complicated
if any(com.is_bool_indexer(x) for x in tup):
return False
return True
def _multi_take(self, tup: Tuple):
"""
Create the indexers for the passed tuple of keys, and
executes the take operation. This allows the take operation to be
executed all at once, rather than once for each dimension.
Improving efficiency.
Parameters
----------
tup : tuple
Tuple of indexers, one per axis.
Returns
-------
values: same type as the object being indexed
"""
# GH 836
o = self.obj
d = {
axis: self._get_listlike_indexer(key, axis)
for (key, axis) in zip(tup, o._AXIS_ORDERS)
}
return o._reindex_with_indexers(d, copy=True, allow_dups=True)
def _handle_lowerdim_multi_index_axis0(self, tup: Tuple):
# we have an axis0 multi-index, handle or raise
axis = self.axis or 0
try:
# fast path for series or for tup devoid of slices
return self._get_label(tup, axis=axis)
except TypeError:
# slices are unhashable
pass
except KeyError as ek:
# raise KeyError if number of indexers match
# else IndexingError will be raised
if len(tup) <= self.obj.index.nlevels and len(tup) > self.ndim:
raise ek
return None
def _getitem_lowerdim(self, tup: Tuple):
# we can directly get the axis result since the axis is specified
if self.axis is not None:
axis = self.obj._get_axis_number(self.axis)
return self._getitem_axis(tup, axis=axis)
# we may have a nested tuples indexer here
if self._is_nested_tuple_indexer(tup):
return self._getitem_nested_tuple(tup)
# we maybe be using a tuple to represent multiple dimensions here
ax0 = self.obj._get_axis(0)
# ...but iloc should handle the tuple as simple integer-location
# instead of checking it as multiindex representation (GH 13797)
if isinstance(ax0, ABCMultiIndex) and self.name != "iloc":
result = self._handle_lowerdim_multi_index_axis0(tup)
if result is not None:
return result
if len(tup) > self.ndim:
raise IndexingError("Too many indexers. handle elsewhere")
for i, key in enumerate(tup):
if is_label_like(key) or isinstance(key, tuple):
section = self._getitem_axis(key, axis=i)
# we have yielded a scalar ?
if not is_list_like_indexer(section):
return section
elif section.ndim == self.ndim:
# we're in the middle of slicing through a MultiIndex
# revise the key wrt to `section` by inserting an _NS
new_key = tup[:i] + (_NS,) + tup[i + 1 :]
else:
new_key = tup[:i] + tup[i + 1 :]
# unfortunately need an odious kludge here because of
# DataFrame transposing convention
if (
isinstance(section, ABCDataFrame)
and i > 0
and len(new_key) == 2
):
a, b = new_key
new_key = b, a
if len(new_key) == 1:
new_key = new_key[0]
# Slices should return views, but calling iloc/loc with a null
# slice returns a new object.
if com.is_null_slice(new_key):
return section
# This is an elided recursive call to iloc/loc/etc'
return getattr(section, self.name)[new_key]
raise IndexingError("not applicable")
def _getitem_nested_tuple(self, tup: Tuple):
# we have a nested tuple so have at least 1 multi-index level
# we should be able to match up the dimensionality here
# we have too many indexers for our dim, but have at least 1
# multi-index dimension, try to see if we have something like
# a tuple passed to a series with a multi-index
if len(tup) > self.ndim:
result = self._handle_lowerdim_multi_index_axis0(tup)
if result is not None:
return result
# this is a series with a multi-index specified a tuple of
# selectors
axis = self.axis or 0
return self._getitem_axis(tup, axis=axis)
# handle the multi-axis by taking sections and reducing
# this is iterative
obj = self.obj
axis = 0
for i, key in enumerate(tup):
if com.is_null_slice(key):
axis += 1
continue
current_ndim = obj.ndim
obj = getattr(obj, self.name)._getitem_axis(key, axis=axis)
axis += 1
# if we have a scalar, we are done
if is_scalar(obj) or not hasattr(obj, "ndim"):
break
# has the dim of the obj changed?
# GH 7199
if obj.ndim < current_ndim:
axis -= 1
return obj
def _get_listlike_indexer(self, key, axis: int, raise_missing: bool = False):
"""
Transform a list-like of keys into a new index and an indexer.
Parameters
----------
key : list-like
Targeted labels.
axis: int
Dimension on which the indexing is being made.
raise_missing: bool, default False
Whether to raise a KeyError if some labels were not found.
Will be removed in the future, and then this method will always behave as
if ``raise_missing=True``.
Raises
------
KeyError
If at least one key was requested but none was found, and
raise_missing=True.
Returns
-------
keyarr: Index
New index (coinciding with 'key' if the axis is unique).
values : array-like
Indexer for the return object, -1 denotes keys not found.
"""
o = self.obj
ax = o._get_axis(axis)
# Have the index compute an indexer or return None
# if it cannot handle:
assert self.name == "loc"
indexer, keyarr = ax._convert_listlike_indexer(key)
# We only act on all found values:
if indexer is not None and (indexer != -1).all():
self._validate_read_indexer(key, indexer, axis, raise_missing=raise_missing)
return ax[indexer], indexer
if ax.is_unique and not getattr(ax, "is_overlapping", False):
indexer = ax.get_indexer_for(key)
keyarr = ax.reindex(keyarr)[0]
else:
keyarr, indexer, new_indexer = ax._reindex_non_unique(keyarr)
self._validate_read_indexer(keyarr, indexer, axis, raise_missing=raise_missing)
return keyarr, indexer
def _getitem_iterable(self, key, axis: int):
"""
Index current object with an an iterable collection of keys.
Parameters
----------
key : iterable
Targeted labels.
axis: int
Dimension on which the indexing is being made.
Raises
------
KeyError
If no key was found. Will change in the future to raise if not all
keys were found.
Returns
-------
scalar, DataFrame, or Series: indexed value(s).
"""
# we assume that not com.is_bool_indexer(key), as that is
# handled before we get here.
self._validate_key(key, axis)
# A collection of keys
keyarr, indexer = self._get_listlike_indexer(key, axis, raise_missing=False)
return self.obj._reindex_with_indexers(
{axis: [keyarr, indexer]}, copy=True, allow_dups=True
)
def _validate_read_indexer(
self, key, indexer, axis: int, raise_missing: bool = False
):
"""
Check that indexer can be used to return a result.
e.g. at least one element was found,
unless the list of keys was actually empty.
Parameters
----------
key : list-like
Targeted labels (only used to show correct error message).
indexer: array-like of booleans
Indices corresponding to the key,
(with -1 indicating not found).
axis: int
Dimension on which the indexing is being made.
raise_missing: bool
Whether to raise a KeyError if some labels are not found. Will be
removed in the future, and then this method will always behave as
if raise_missing=True.
Raises
------
KeyError
If at least one key was requested but none was found, and
raise_missing=True.
"""
ax = self.obj._get_axis(axis)
if len(key) == 0:
return
# Count missing values:
missing = (indexer < 0).sum()
if missing:
if missing == len(indexer):
axis_name = self.obj._get_axis_name(axis)
raise KeyError(f"None of [{key}] are in the [{axis_name}]")
# We (temporarily) allow for some missing keys with .loc, except in
# some cases (e.g. setting) in which "raise_missing" will be False
if not (self.name == "loc" and not raise_missing):
not_found = list(set(key) - set(ax))
raise KeyError(f"{not_found} not in index")
# we skip the warning on Categorical/Interval
# as this check is actually done (check for
# non-missing values), but a bit later in the
# code, so we want to avoid warning & then
# just raising
if not (ax.is_categorical() or ax.is_interval()):
raise KeyError(
"Passing list-likes to .loc or [] with any missing labels "
"is no longer supported, see "
"https://pandas.pydata.org/pandas-docs/stable/user_guide/indexing.html#deprecate-loc-reindex-listlike" # noqa:E501
)
def _convert_to_indexer(self, key, axis: int, is_setter: bool = False):
raise AbstractMethodError(self)
def __getitem__(self, key):
if type(key) is tuple:
key = tuple(com.apply_if_callable(x, self.obj) for x in key)
if self._is_scalar_access(key):
try:
return self.obj._get_value(*key, takeable=self._takeable)
except (KeyError, IndexError, AttributeError):
# AttributeError for IntervalTree get_value
pass
return self._getitem_tuple(key)
else:
# we by definition only have the 0th axis
axis = self.axis or 0
maybe_callable = com.apply_if_callable(key, self.obj)
return self._getitem_axis(maybe_callable, axis=axis)
def _is_scalar_access(self, key: Tuple):
raise NotImplementedError()
def _getitem_axis(self, key, axis: int):
raise NotImplementedError()
def _getbool_axis(self, key, axis: int):
# caller is responsible for ensuring non-None axis
labels = self.obj._get_axis(axis)
key = check_bool_indexer(labels, key)
inds = key.nonzero()[0]
return self.obj._take_with_is_copy(inds, axis=axis)
@Appender(IndexingMixin.loc.__doc__)
class _LocIndexer(_LocationIndexer):
_takeable: bool = False
_valid_types = (
"labels (MUST BE IN THE INDEX), slices of labels (BOTH "
"endpoints included! Can be slices of integers if the "
"index is integers), listlike of labels, boolean"
)
@Appender(_LocationIndexer._validate_key.__doc__)
def _validate_key(self, key, axis: int):
# valid for a collection of labels (we check their presence later)
# slice of labels (where start-end in labels)
# slice of integers (only if in the labels)
# boolean
if isinstance(key, slice):
return
if com.is_bool_indexer(key):
return
if not is_list_like_indexer(key):
labels = self.obj._get_axis(axis)
labels._convert_scalar_indexer(key, kind="loc")
def _is_scalar_access(self, key: Tuple) -> bool:
"""
Returns
-------
bool
"""
# this is a shortcut accessor to both .loc and .iloc
# that provide the equivalent access of .at and .iat
# a) avoid getting things via sections and (to minimize dtype changes)
# b) provide a performant path
if len(key) != self.ndim:
return False
for i, k in enumerate(key):
if not is_scalar(k):
return False
ax = self.obj.axes[i]
if isinstance(ax, ABCMultiIndex):
return False
if isinstance(k, str) and ax._supports_partial_string_indexing:
# partial string indexing, df.loc['2000', 'A']
# should not be considered scalar
return False
if not ax.is_unique:
return False
return True
def _get_partial_string_timestamp_match_key(self, key, labels):
"""
Translate any partial string timestamp matches in key, returning the
new key.
(GH 10331)
"""
if isinstance(labels, ABCMultiIndex):
if (
isinstance(key, str)
and labels.levels[0]._supports_partial_string_indexing
):
# Convert key '2016-01-01' to
# ('2016-01-01'[, slice(None, None, None)]+)
key = tuple([key] + [slice(None)] * (len(labels.levels) - 1))
if isinstance(key, tuple):
# Convert (..., '2016-01-01', ...) in tuple to
# (..., slice('2016-01-01', '2016-01-01', None), ...)
new_key = []
for i, component in enumerate(key):
if (
isinstance(component, str)
and labels.levels[i]._supports_partial_string_indexing
):
new_key.append(slice(component, component, None))
else:
new_key.append(component)
key = tuple(new_key)
return key
def _getitem_axis(self, key, axis: int):
key = item_from_zerodim(key)
if is_iterator(key):
key = list(key)
labels = self.obj._get_axis(axis)
key = self._get_partial_string_timestamp_match_key(key, labels)
if isinstance(key, slice):
self._validate_key(key, axis)
return self._get_slice_axis(key, axis=axis)
elif com.is_bool_indexer(key):
return self._getbool_axis(key, axis=axis)
elif is_list_like_indexer(key):
# convert various list-like indexers
# to a list of keys
# we will use the *values* of the object
# and NOT the index if its a PandasObject
if isinstance(labels, ABCMultiIndex):
if isinstance(key, (ABCSeries, np.ndarray)) and key.ndim <= 1:
# Series, or 0,1 ndim ndarray
# GH 14730
key = list(key)
elif isinstance(key, ABCDataFrame):
# GH 15438
raise NotImplementedError(
"Indexing a MultiIndex with a "
"DataFrame key is not "
"implemented"
)
elif hasattr(key, "ndim") and key.ndim > 1:
raise NotImplementedError(
"Indexing a MultiIndex with a "
"multidimensional key is not "
"implemented"
)
if (
not isinstance(key, tuple)
and len(key)
and not isinstance(key[0], tuple)
):
key = tuple([key])
# an iterable multi-selection
if not (isinstance(key, tuple) and isinstance(labels, ABCMultiIndex)):
if hasattr(key, "ndim") and key.ndim > 1:
raise ValueError("Cannot index with multidimensional key")
return self._getitem_iterable(key, axis=axis)
# nested tuple slicing
if is_nested_tuple(key, labels):
locs = labels.get_locs(key)
indexer = [slice(None)] * self.ndim
indexer[axis] = locs
return self.obj.iloc[tuple(indexer)]
# fall thru to straight lookup
self._validate_key(key, axis)
return self._get_label(key, axis=axis)
def _get_slice_axis(self, slice_obj: slice, axis: int):
"""
This is pretty simple as we just have to deal with labels.
"""
# caller is responsible for ensuring non-None axis
obj = self.obj
if not need_slice(slice_obj):
return obj.copy(deep=False)
labels = obj._get_axis(axis)
indexer = labels.slice_indexer(
slice_obj.start, slice_obj.stop, slice_obj.step, kind=self.name
)
if isinstance(indexer, slice):
return self.obj._slice(indexer, axis=axis, kind="iloc")
else:
# DatetimeIndex overrides Index.slice_indexer and may
# return a DatetimeIndex instead of a slice object.
return self.obj.take(indexer, axis=axis)
def _convert_to_indexer(self, key, axis: int, is_setter: bool = False):
"""
Convert indexing key into something we can use to do actual fancy
indexing on a ndarray.
Examples
ix[:5] -> slice(0, 5)
ix[[1,2,3]] -> [1,2,3]
ix[['foo', 'bar', 'baz']] -> [i, j, k] (indices of foo, bar, baz)
Going by Zen of Python?
'In the face of ambiguity, refuse the temptation to guess.'
raise AmbiguousIndexError with integer labels?
- No, prefer label-based indexing
"""
labels = self.obj._get_axis(axis)
if isinstance(key, slice):
return labels._convert_slice_indexer(key, kind="loc")
if is_scalar(key):
# try to find out correct indexer, if not type correct raise
try:
key = labels._convert_scalar_indexer(key, kind="loc")
except TypeError:
# but we will allow setting
if not is_setter:
raise
# see if we are positional in nature
is_int_index = labels.is_integer()
is_int_positional = is_integer(key) and not is_int_index
if is_scalar(key) or isinstance(labels, ABCMultiIndex):
# Otherwise get_loc will raise InvalidIndexError
# if we are a label return me
try:
return labels.get_loc(key)
except LookupError:
if isinstance(key, tuple) and isinstance(labels, ABCMultiIndex):
if len(key) == labels.nlevels:
return {"key": key}
raise
except TypeError:
pass
except ValueError:
if not is_int_positional:
raise
# a positional
if is_int_positional:
# if we are setting and its not a valid location
# its an insert which fails by definition
# always valid
return {"key": key}
if is_nested_tuple(key, labels):
return labels.get_locs(key)
elif is_list_like_indexer(key):
if com.is_bool_indexer(key):
key = check_bool_indexer(labels, key)
(inds,) = key.nonzero()
return inds
else:
# When setting, missing keys are not allowed, even with .loc:
return self._get_listlike_indexer(key, axis, raise_missing=True)[1]
else:
try:
return labels.get_loc(key)
except LookupError:
# allow a not found key only if we are a setter
if not is_list_like_indexer(key):
return {"key": key}
raise
@Appender(IndexingMixin.iloc.__doc__)
class _iLocIndexer(_LocationIndexer):
_valid_types = (
"integer, integer slice (START point is INCLUDED, END "
"point is EXCLUDED), listlike of integers, boolean array"
)
_takeable = True
def _validate_key(self, key, axis: int):
if com.is_bool_indexer(key):
if hasattr(key, "index") and isinstance(key.index, Index):
if key.index.inferred_type == "integer":
raise NotImplementedError(
"iLocation based boolean "
"indexing on an integer type "
"is not available"
)
raise ValueError(
"iLocation based boolean indexing cannot use "
"an indexable as a mask"
)
return
if isinstance(key, slice):
return
elif is_integer(key):
self._validate_integer(key, axis)
elif isinstance(key, tuple):
# a tuple should already have been caught by this point
# so don't treat a tuple as a valid indexer
raise IndexingError("Too many indexers")
elif is_list_like_indexer(key):
arr = np.array(key)
len_axis = len(self.obj._get_axis(axis))
# check that the key has a numeric dtype
if not is_numeric_dtype(arr.dtype):
raise IndexError(f".iloc requires numeric indexers, got {arr}")
# check that the key does not exceed the maximum size of the index
if len(arr) and (arr.max() >= len_axis or arr.min() < -len_axis):
raise IndexError("positional indexers are out-of-bounds")
else:
raise ValueError(f"Can only index by location with a [{self._valid_types}]")
def _has_valid_setitem_indexer(self, indexer):
self._has_valid_positional_setitem_indexer(indexer)
def _is_scalar_access(self, key: Tuple) -> bool:
"""
Returns
-------
bool
"""
# this is a shortcut accessor to both .loc and .iloc
# that provide the equivalent access of .at and .iat
# a) avoid getting things via sections and (to minimize dtype changes)
# b) provide a performant path
if len(key) != self.ndim:
return False
for i, k in enumerate(key):
if not is_integer(k):
return False
ax = self.obj.axes[i]
if not ax.is_unique:
return False
return True
def _validate_integer(self, key: int, axis: int) -> None:
"""
Check that 'key' is a valid position in the desired axis.
Parameters
----------
key : int
Requested position.
axis : int
Desired axis.
Raises
------
IndexError
If 'key' is not a valid position in axis 'axis'.
"""
len_axis = len(self.obj._get_axis(axis))
if key >= len_axis or key < -len_axis:
raise IndexError("single positional indexer is out-of-bounds")
def _getitem_tuple(self, tup: Tuple):
self._has_valid_tuple(tup)
try:
return self._getitem_lowerdim(tup)
except IndexingError:
pass
retval = self.obj
axis = 0
for i, key in enumerate(tup):
if com.is_null_slice(key):
axis += 1
continue
retval = getattr(retval, self.name)._getitem_axis(key, axis=axis)
# if the dim was reduced, then pass a lower-dim the next time
if retval.ndim < self.ndim:
# TODO: this is never reached in tests; can we confirm that
# it is impossible?
axis -= 1
# try to get for the next axis
axis += 1
return retval
def _get_list_axis(self, key, axis: int):
"""
Return Series values by list or array of integers.
Parameters
----------
key : list-like positional indexer
axis : int
Returns
-------
Series object
Notes
-----
`axis` can only be zero.
"""
try:
return self.obj._take_with_is_copy(key, axis=axis)
except IndexError:
# re-raise with different error message
raise IndexError("positional indexers are out-of-bounds")
def _getitem_axis(self, key, axis: int):
if isinstance(key, slice):
return self._get_slice_axis(key, axis=axis)
if isinstance(key, list):
key = np.asarray(key)
if com.is_bool_indexer(key):
self._validate_key(key, axis)
return self._getbool_axis(key, axis=axis)
# a list of integers
elif is_list_like_indexer(key):
return self._get_list_axis(key, axis=axis)
# a single integer
else:
key = item_from_zerodim(key)
if not is_integer(key):
raise TypeError("Cannot index by location index with a non-integer key")
# validate the location
self._validate_integer(key, axis)
return self.obj._ixs(key, axis=axis)
def _get_slice_axis(self, slice_obj: slice, axis: int):
# caller is responsible for ensuring non-None axis
obj = self.obj
if not need_slice(slice_obj):
return obj.copy(deep=False)
labels = obj._get_axis(axis)
indexer = labels._convert_slice_indexer(slice_obj, kind="iloc")
return self.obj._slice(indexer, axis=axis, kind="iloc")
def _convert_to_indexer(self, key, axis: int, is_setter: bool = False):
"""
Much simpler as we only have to deal with our valid types.
"""
labels = self.obj._get_axis(axis)
# make need to convert a float key
if isinstance(key, slice):
return labels._convert_slice_indexer(key, kind="iloc")
elif is_float(key):
return labels._convert_scalar_indexer(key, kind="iloc")
self._validate_key(key, axis)
return key
class _ScalarAccessIndexer(_NDFrameIndexerBase):
"""
Access scalars quickly.
"""
def _convert_key(self, key, is_setter: bool = False):
raise AbstractMethodError(self)
def __getitem__(self, key):
if not isinstance(key, tuple):
# we could have a convertible item here (e.g. Timestamp)
if not is_list_like_indexer(key):
key = tuple([key])
else:
raise ValueError("Invalid call for scalar access (getting)!")
key = self._convert_key(key)
return self.obj._get_value(*key, takeable=self._takeable)
def __setitem__(self, key, value):
if isinstance(key, tuple):
key = tuple(com.apply_if_callable(x, self.obj) for x in key)
else:
# scalar callable may return tuple
key = com.apply_if_callable(key, self.obj)
if not isinstance(key, tuple):
key = _tuplify(self.ndim, key)
if len(key) != self.ndim:
raise ValueError("Not enough indexers for scalar access (setting)!")
key = list(self._convert_key(key, is_setter=True))
self.obj._set_value(*key, value=value, takeable=self._takeable)
@Appender(IndexingMixin.at.__doc__)
class _AtIndexer(_ScalarAccessIndexer):
_takeable = False
def _convert_key(self, key, is_setter: bool = False):
"""
Require they keys to be the same type as the index. (so we don't
fallback)
"""
# allow arbitrary setting
if is_setter:
return list(key)
for ax, i in zip(self.obj.axes, key):
if ax.is_integer():
if not is_integer(i):
raise ValueError(
"At based indexing on an integer index "
"can only have integer indexers"
)
else:
if is_integer(i) and not (ax.holds_integer() or ax.is_floating()):
raise ValueError(
"At based indexing on an non-integer "
"index can only have non-integer "
"indexers"
)
return key
@Appender(IndexingMixin.iat.__doc__)
class _iAtIndexer(_ScalarAccessIndexer):
_takeable = True
def _convert_key(self, key, is_setter: bool = False):
"""
Require integer args. (and convert to label arguments)
"""
for a, i in zip(self.obj.axes, key):
if not is_integer(i):
raise ValueError("iAt based indexing can only have integer indexers")
return key
def _tuplify(ndim: int, loc: Hashable) -> Tuple[Union[Hashable, slice], ...]:
"""
Given an indexer for the first dimension, create an equivalent tuple
for indexing over all dimensions.
Parameters
----------
ndim : int
loc : object
Returns
-------
tuple
"""
_tup: List[Union[Hashable, slice]]
_tup = [slice(None, None) for _ in range(ndim)]
_tup[0] = loc
return tuple(_tup)
def convert_to_index_sliceable(obj, key):
"""
If we are index sliceable, then return my slicer, otherwise return None.
"""
idx = obj.index
if isinstance(key, slice):
return idx._convert_slice_indexer(key, kind="getitem")
elif isinstance(key, str):
# we are an actual column
if key in obj._data.items:
return None
# We might have a datetimelike string that we can translate to a
# slice here via partial string indexing
if idx._supports_partial_string_indexing:
try:
return idx._get_string_slice(key)
except (KeyError, ValueError, NotImplementedError):
return None
return None
def check_bool_indexer(index: Index, key) -> np.ndarray:
"""
Check if key is a valid boolean indexer for an object with such index and
perform reindexing or conversion if needed.
This function assumes that is_bool_indexer(key) == True.
Parameters
----------
index : Index
Index of the object on which the indexing is done.
key : list-like
Boolean indexer to check.
Returns
-------
np.array
Resulting key.
Raises
------
IndexError
If the key does not have the same length as index.
IndexingError
If the index of the key is unalignable to index.
"""
result = key
if isinstance(key, ABCSeries) and not key.index.equals(index):
result = result.reindex(index)
mask = isna(result._values)
if mask.any():
raise IndexingError(
"Unalignable boolean Series provided as "
"indexer (index of the boolean Series and of "
"the indexed object do not match)."
)
result = result.astype(bool)._values
else:
# key might be sparse / object-dtype bool, check_array_indexer needs bool array
result = np.asarray(result, dtype=bool)
result = check_array_indexer(index, result)
return result
def convert_missing_indexer(indexer):
"""
Reverse convert a missing indexer, which is a dict
return the scalar indexer and a boolean indicating if we converted
"""
if isinstance(indexer, dict):
# a missing key (but not a tuple indexer)
indexer = indexer["key"]
if isinstance(indexer, bool):
raise KeyError("cannot use a single bool to index into setitem")
return indexer, True
return indexer, False
def convert_from_missing_indexer_tuple(indexer, axes):
"""
Create a filtered indexer that doesn't have any missing indexers.
"""
def get_indexer(_i, _idx):
return axes[_i].get_loc(_idx["key"]) if isinstance(_idx, dict) else _idx
return tuple(get_indexer(_i, _idx) for _i, _idx in enumerate(indexer))
def maybe_convert_ix(*args):
"""
We likely want to take the cross-product.
"""
ixify = True
for arg in args:
if not isinstance(arg, (np.ndarray, list, ABCSeries, Index)):
ixify = False
if ixify:
return np.ix_(*args)
else:
return args
def is_nested_tuple(tup, labels) -> bool:
"""
Returns
-------
bool
"""
# check for a compatible nested tuple and multiindexes among the axes
if not isinstance(tup, tuple):
return False
for i, k in enumerate(tup):
if is_list_like(k) or isinstance(k, slice):
return isinstance(labels, ABCMultiIndex)
return False
def is_label_like(key) -> bool:
"""
Returns
-------
bool
"""
# select a label or row
return not isinstance(key, slice) and not is_list_like_indexer(key)
def need_slice(obj) -> bool:
"""
Returns
-------
bool
"""
return (
obj.start is not None
or obj.stop is not None
or (obj.step is not None and obj.step != 1)
)
def _non_reducing_slice(slice_):
"""
Ensurse that a slice doesn't reduce to a Series or Scalar.
Any user-paseed `subset` should have this called on it
to make sure we're always working with DataFrames.
"""
# default to column slice, like DataFrame
# ['A', 'B'] -> IndexSlices[:, ['A', 'B']]
kinds = (ABCSeries, np.ndarray, Index, list, str)
if isinstance(slice_, kinds):
slice_ = IndexSlice[:, slice_]
def pred(part) -> bool:
"""
Returns
-------
bool
True if slice does *not* reduce,
False if `part` is a tuple.
"""
# true when slice does *not* reduce, False when part is a tuple,
# i.e. MultiIndex slice
return (isinstance(part, slice) or is_list_like(part)) and not isinstance(
part, tuple
)
if not is_list_like(slice_):
if not isinstance(slice_, slice):
# a 1-d slice, like df.loc[1]
slice_ = [[slice_]]
else:
# slice(a, b, c)
slice_ = [slice_] # to tuplize later
else:
slice_ = [part if pred(part) else [part] for part in slice_]
return tuple(slice_)
def _maybe_numeric_slice(df, slice_, include_bool=False):
"""
Want nice defaults for background_gradient that don't break
with non-numeric data. But if slice_ is passed go with that.
"""
if slice_ is None:
dtypes = [np.number]
if include_bool:
dtypes.append(bool)
slice_ = IndexSlice[:, df.select_dtypes(include=dtypes).columns]
return slice_
def _can_do_equal_len(labels, value, plane_indexer, lplane_indexer, obj) -> bool:
"""
Returns
-------
bool
True if we have an equal len settable.
"""
if not len(labels) == 1 or not np.iterable(value) or is_scalar(plane_indexer[0]):
return False
item = labels[0]
index = obj[item].index
values_len = len(value)
# equal len list/ndarray
if len(index) == values_len:
return True
elif lplane_indexer == values_len:
return True
return False
from typing import Hashable, List, Tuple, Union
import numpy as np
from pandas._libs.indexing import _NDFrameIndexerBase
from pandas._libs.lib import item_from_zerodim
from pandas.errors import AbstractMethodError
from pandas.util._decorators import Appender
from pandas.core.dtypes.common import (
is_float,
is_integer,
is_iterator,
is_list_like,
is_numeric_dtype,
is_scalar,
is_sequence,
)
from pandas.core.dtypes.concat import concat_compat
from pandas.core.dtypes.generic import ABCDataFrame, ABCMultiIndex, ABCSeries
from pandas.core.dtypes.missing import _infer_fill_value, isna
import pandas.core.common as com
from pandas.core.indexers import (
check_array_indexer,
is_list_like_indexer,
length_of_indexer,
)
from pandas.core.indexes.api import Index
from pandas.core.indexes.base import InvalidIndexError
# "null slice"
_NS = slice(None, None)
# the public IndexSlicerMaker
class _IndexSlice:
"""
Create an object to more easily perform multi-index slicing.
See Also
--------
MultiIndex.remove_unused_levels : New MultiIndex with no unused levels.
Notes
-----
See :ref:`Defined Levels <advanced.shown_levels>`
for further info on slicing a MultiIndex.
Examples
--------
>>> midx = pd.MultiIndex.from_product([['A0','A1'], ['B0','B1','B2','B3']])
>>> columns = ['foo', 'bar']
>>> dfmi = pd.DataFrame(np.arange(16).reshape((len(midx), len(columns))),
index=midx, columns=columns)
Using the default slice command:
>>> dfmi.loc[(slice(None), slice('B0', 'B1')), :]
foo bar
A0 B0 0 1
B1 2 3
A1 B0 8 9
B1 10 11
Using the IndexSlice class for a more intuitive command:
>>> idx = pd.IndexSlice
>>> dfmi.loc[idx[:, 'B0':'B1'], :]
foo bar
A0 B0 0 1
B1 2 3
A1 B0 8 9
B1 10 11
"""
def __getitem__(self, arg):
return arg
IndexSlice = _IndexSlice()
class IndexingError(Exception):
pass
class IndexingMixin:
"""Mixin for adding .loc/.iloc/.at/.iat to Datafames and Series.
"""
@property
def iloc(self) -> "_iLocIndexer":
"""
Purely integer-location based indexing for selection by position.
``.iloc[]`` is primarily integer position based (from ``0`` to
``length-1`` of the axis), but may also be used with a boolean
array.
Allowed inputs are:
- An integer, e.g. ``5``.
- A list or array of integers, e.g. ``[4, 3, 0]``.
- A slice object with ints, e.g. ``1:7``.
- A boolean array.
- A ``callable`` function with one argument (the calling Series or
DataFrame) and that returns valid output for indexing (one of the above).
This is useful in method chains, when you don't have a reference to the
calling object, but would like to base your selection on some value.
``.iloc`` will raise ``IndexError`` if a requested indexer is
out-of-bounds, except *slice* indexers which allow out-of-bounds
indexing (this conforms with python/numpy *slice* semantics).
See more at :ref:`Selection by Position <indexing.integer>`.
See Also
--------
DataFrame.iat : Fast integer location scalar accessor.
DataFrame.loc : Purely label-location based indexer for selection by label.
Series.iloc : Purely integer-location based indexing for
selection by position.
Examples
--------
>>> mydict = [{'a': 1, 'b': 2, 'c': 3, 'd': 4},
... {'a': 100, 'b': 200, 'c': 300, 'd': 400},
... {'a': 1000, 'b': 2000, 'c': 3000, 'd': 4000 }]
>>> df = pd.DataFrame(mydict)
>>> df
a b c d
0 1 2 3 4
1 100 200 300 400
2 1000 2000 3000 4000
**Indexing just the rows**
With a scalar integer.
>>> type(df.iloc[0])
<class 'pandas.core.series.Series'>
>>> df.iloc[0]
a 1
b 2
c 3
d 4
Name: 0, dtype: int64
With a list of integers.
>>> df.iloc[[0]]
a b c d
0 1 2 3 4
>>> type(df.iloc[[0]])
<class 'pandas.core.frame.DataFrame'>
>>> df.iloc[[0, 1]]
a b c d
0 1 2 3 4
1 100 200 300 400
With a `slice` object.
>>> df.iloc[:3]
a b c d
0 1 2 3 4
1 100 200 300 400
2 1000 2000 3000 4000
With a boolean mask the same length as the index.
>>> df.iloc[[True, False, True]]
a b c d
0 1 2 3 4
2 1000 2000 3000 4000
With a callable, useful in method chains. The `x` passed
to the ``lambda`` is the DataFrame being sliced. This selects
the rows whose index label even.
>>> df.iloc[lambda x: x.index % 2 == 0]
a b c d
0 1 2 3 4
2 1000 2000 3000 4000
**Indexing both axes**
You can mix the indexer types for the index and columns. Use ``:`` to
select the entire axis.
With scalar integers.
>>> df.iloc[0, 1]
2
With lists of integers.
>>> df.iloc[[0, 2], [1, 3]]
b d
0 2 4
2 2000 4000
With `slice` objects.
>>> df.iloc[1:3, 0:3]
a b c
1 100 200 300
2 1000 2000 3000
With a boolean array whose length matches the columns.
>>> df.iloc[:, [True, False, True, False]]
a c
0 1 3
1 100 300
2 1000 3000
With a callable function that expects the Series or DataFrame.
>>> df.iloc[:, lambda df: [0, 2]]
a c
0 1 3
1 100 300
2 1000 3000
"""
return _iLocIndexer("iloc", self)
@property
def loc(self) -> "_LocIndexer":
"""
Access a group of rows and columns by label(s) or a boolean array.
``.loc[]`` is primarily label based, but may also be used with a
boolean array.
Allowed inputs are:
- A single label, e.g. ``5`` or ``'a'``, (note that ``5`` is
interpreted as a *label* of the index, and **never** as an
integer position along the index).
- A list or array of labels, e.g. ``['a', 'b', 'c']``.
- A slice object with labels, e.g. ``'a':'f'``.
.. warning:: Note that contrary to usual python slices, **both** the
start and the stop are included
- A boolean array of the same length as the axis being sliced,
e.g. ``[True, False, True]``.
- A ``callable`` function with one argument (the calling Series or
DataFrame) and that returns valid output for indexing (one of the above)
See more at :ref:`Selection by Label <indexing.label>`
Raises
------
KeyError
If any items are not found.
See Also
--------
DataFrame.at : Access a single value for a row/column label pair.
DataFrame.iloc : Access group of rows and columns by integer position(s).
DataFrame.xs : Returns a cross-section (row(s) or column(s)) from the
Series/DataFrame.
Series.loc : Access group of values using labels.
Examples
--------
**Getting values**
>>> df = pd.DataFrame([[1, 2], [4, 5], [7, 8]],
... index=['cobra', 'viper', 'sidewinder'],
... columns=['max_speed', 'shield'])
>>> df
max_speed shield
cobra 1 2
viper 4 5
sidewinder 7 8
Single label. Note this returns the row as a Series.
>>> df.loc['viper']
max_speed 4
shield 5
Name: viper, dtype: int64
List of labels. Note using ``[[]]`` returns a DataFrame.
>>> df.loc[['viper', 'sidewinder']]
max_speed shield
viper 4 5
sidewinder 7 8
Single label for row and column
>>> df.loc['cobra', 'shield']
2
Slice with labels for row and single label for column. As mentioned
above, note that both the start and stop of the slice are included.
>>> df.loc['cobra':'viper', 'max_speed']
cobra 1
viper 4
Name: max_speed, dtype: int64
Boolean list with the same length as the row axis
>>> df.loc[[False, False, True]]
max_speed shield
sidewinder 7 8
Conditional that returns a boolean Series
>>> df.loc[df['shield'] > 6]
max_speed shield
sidewinder 7 8
Conditional that returns a boolean Series with column labels specified
>>> df.loc[df['shield'] > 6, ['max_speed']]
max_speed
sidewinder 7
Callable that returns a boolean Series
>>> df.loc[lambda df: df['shield'] == 8]
max_speed shield
sidewinder 7 8
**Setting values**
Set value for all items matching the list of labels
>>> df.loc[['viper', 'sidewinder'], ['shield']] = 50
>>> df
max_speed shield
cobra 1 2
viper 4 50
sidewinder 7 50
Set value for an entire row
>>> df.loc['cobra'] = 10
>>> df
max_speed shield
cobra 10 10
viper 4 50
sidewinder 7 50
Set value for an entire column
>>> df.loc[:, 'max_speed'] = 30
>>> df
max_speed shield
cobra 30 10
viper 30 50
sidewinder 30 50
Set value for rows matching callable condition
>>> df.loc[df['shield'] > 35] = 0
>>> df
max_speed shield
cobra 30 10
viper 0 0
sidewinder 0 0
**Getting values on a DataFrame with an index that has integer labels**
Another example using integers for the index
>>> df = pd.DataFrame([[1, 2], [4, 5], [7, 8]],
... index=[7, 8, 9], columns=['max_speed', 'shield'])
>>> df
max_speed shield
7 1 2
8 4 5
9 7 8
Slice with integer labels for rows. As mentioned above, note that both
the start and stop of the slice are included.
>>> df.loc[7:9]
max_speed shield
7 1 2
8 4 5
9 7 8
**Getting values with a MultiIndex**
A number of examples using a DataFrame with a MultiIndex
>>> tuples = [
... ('cobra', 'mark i'), ('cobra', 'mark ii'),
... ('sidewinder', 'mark i'), ('sidewinder', 'mark ii'),
... ('viper', 'mark ii'), ('viper', 'mark iii')
... ]
>>> index = pd.MultiIndex.from_tuples(tuples)
>>> values = [[12, 2], [0, 4], [10, 20],
... [1, 4], [7, 1], [16, 36]]
>>> df = pd.DataFrame(values, columns=['max_speed', 'shield'], index=index)
>>> df
max_speed shield
cobra mark i 12 2
mark ii 0 4
sidewinder mark i 10 20
mark ii 1 4
viper mark ii 7 1
mark iii 16 36
Single label. Note this returns a DataFrame with a single index.
>>> df.loc['cobra']
max_speed shield
mark i 12 2
mark ii 0 4
Single index tuple. Note this returns a Series.
>>> df.loc[('cobra', 'mark ii')]
max_speed 0
shield 4
Name: (cobra, mark ii), dtype: int64
Single label for row and column. Similar to passing in a tuple, this
returns a Series.
>>> df.loc['cobra', 'mark i']
max_speed 12
shield 2
Name: (cobra, mark i), dtype: int64
Single tuple. Note using ``[[]]`` returns a DataFrame.
>>> df.loc[[('cobra', 'mark ii')]]
max_speed shield
cobra mark ii 0 4
Single tuple for the index with a single label for the column
>>> df.loc[('cobra', 'mark i'), 'shield']
2
Slice from index tuple to single label
>>> df.loc[('cobra', 'mark i'):'viper']
max_speed shield
cobra mark i 12 2
mark ii 0 4
sidewinder mark i 10 20
mark ii 1 4
viper mark ii 7 1
mark iii 16 36
Slice from index tuple to index tuple
>>> df.loc[('cobra', 'mark i'):('viper', 'mark ii')]
max_speed shield
cobra mark i 12 2
mark ii 0 4
sidewinder mark i 10 20
mark ii 1 4
viper mark ii 7 1
"""
return _LocIndexer("loc", self)
@property
def at(self) -> "_AtIndexer":
"""
Access a single value for a row/column label pair.
Similar to ``loc``, in that both provide label-based lookups. Use
``at`` if you only need to get or set a single value in a DataFrame
or Series.
Raises
------
KeyError
If 'label' does not exist in DataFrame.
See Also
--------
DataFrame.iat : Access a single value for a row/column pair by integer
position.
DataFrame.loc : Access a group of rows and columns by label(s).
Series.at : Access a single value using a label.
Examples
--------
>>> df = pd.DataFrame([[0, 2, 3], [0, 4, 1], [10, 20, 30]],
... index=[4, 5, 6], columns=['A', 'B', 'C'])
>>> df
A B C
4 0 2 3
5 0 4 1
6 10 20 30
Get value at specified row/column pair
>>> df.at[4, 'B']
2
Set value at specified row/column pair
>>> df.at[4, 'B'] = 10
>>> df.at[4, 'B']
10
Get value within a Series
>>> df.loc[5].at['B']
4
"""
return _AtIndexer("at", self)
@property
def iat(self) -> "_iAtIndexer":
"""
Access a single value for a row/column pair by integer position.
Similar to ``iloc``, in that both provide integer-based lookups. Use
``iat`` if you only need to get or set a single value in a DataFrame
or Series.
Raises
------
IndexError
When integer position is out of bounds.
See Also
--------
DataFrame.at : Access a single value for a row/column label pair.
DataFrame.loc : Access a group of rows and columns by label(s).
DataFrame.iloc : Access a group of rows and columns by integer position(s).
Examples
--------
>>> df = pd.DataFrame([[0, 2, 3], [0, 4, 1], [10, 20, 30]],
... columns=['A', 'B', 'C'])
>>> df
A B C
0 0 2 3
1 0 4 1
2 10 20 30
Get value at specified row/column pair
>>> df.iat[1, 2]
1
Set value at specified row/column pair
>>> df.iat[1, 2] = 10
>>> df.iat[1, 2]
10
Get value within a series
>>> df.loc[0].iat[1]
2
"""
return _iAtIndexer("iat", self)
class _LocationIndexer(_NDFrameIndexerBase):
_valid_types: str
axis = None
def __call__(self, axis=None):
# we need to return a copy of ourselves
new_self = type(self)(self.name, self.obj)
if axis is not None:
axis = self.obj._get_axis_number(axis)
new_self.axis = axis
return new_self
def _get_label(self, label, axis: int):
if self.ndim == 1:
# for perf reasons we want to try _xs first
# as its basically direct indexing
# but will fail when the index is not present
# see GH5667
return self.obj._xs(label, axis=axis)
elif isinstance(label, tuple) and isinstance(label[axis], slice):
raise IndexingError("no slices here, handle elsewhere")
return self.obj._xs(label, axis=axis)
def _get_setitem_indexer(self, key):
if self.axis is not None:
return self._convert_tuple(key, is_setter=True)
ax = self.obj._get_axis(0)
if isinstance(ax, ABCMultiIndex) and self.name != "iloc":
try:
return ax.get_loc(key)
except (TypeError, KeyError, InvalidIndexError):
# TypeError e.g. passed a bool
pass
if isinstance(key, tuple):
try:
return self._convert_tuple(key, is_setter=True)
except IndexingError:
pass
if isinstance(key, range):
return list(key)
try:
return self._convert_to_indexer(key, axis=0, is_setter=True)
except TypeError as e:
# invalid indexer type vs 'other' indexing errors
if "cannot do" in str(e):
raise
raise IndexingError(key)
def __setitem__(self, key, value):
if isinstance(key, tuple):
key = tuple(com.apply_if_callable(x, self.obj) for x in key)
else:
key = com.apply_if_callable(key, self.obj)
indexer = self._get_setitem_indexer(key)
self._setitem_with_indexer(indexer, value)
def _validate_key(self, key, axis: int):
"""
Ensure that key is valid for current indexer.
Parameters
----------
key : scalar, slice or list-like
Key requested.
axis : int
Dimension on which the indexing is being made.
Raises
------
TypeError
If the key (or some element of it) has wrong type.
IndexError
If the key (or some element of it) is out of bounds.
KeyError
If the key was not found.
"""
raise AbstractMethodError(self)
def _has_valid_tuple(self, key: Tuple):
"""
Check the key for valid keys across my indexer.
"""
for i, k in enumerate(key):
if i >= self.ndim:
raise IndexingError("Too many indexers")
try:
self._validate_key(k, i)
except ValueError:
raise ValueError(
"Location based indexing can only have "
f"[{self._valid_types}] types"
)
def _is_nested_tuple_indexer(self, tup: Tuple) -> bool:
"""
Returns
-------
bool
"""
if any(isinstance(ax, ABCMultiIndex) for ax in self.obj.axes):
return any(is_nested_tuple(tup, ax) for ax in self.obj.axes)
return False
def _convert_tuple(self, key, is_setter: bool = False):
keyidx = []
if self.axis is not None:
axis = self.obj._get_axis_number(self.axis)
for i in range(self.ndim):
if i == axis:
keyidx.append(
self._convert_to_indexer(key, axis=axis, is_setter=is_setter)
)
else:
keyidx.append(slice(None))
else:
for i, k in enumerate(key):
if i >= self.ndim:
raise IndexingError("Too many indexers")
idx = self._convert_to_indexer(k, axis=i, is_setter=is_setter)
keyidx.append(idx)
return tuple(keyidx)
def _has_valid_setitem_indexer(self, indexer) -> bool:
return True
def _has_valid_positional_setitem_indexer(self, indexer) -> bool:
"""
Validate that a positional indexer cannot enlarge its target
will raise if needed, does not modify the indexer externally.
Returns
-------
bool
"""
if isinstance(indexer, dict):
raise IndexError(f"{self.name} cannot enlarge its target object")
else:
if not isinstance(indexer, tuple):
indexer = _tuplify(self.ndim, indexer)
for ax, i in zip(self.obj.axes, indexer):
if isinstance(i, slice):
# should check the stop slice?
pass
elif is_list_like_indexer(i):
# should check the elements?
pass
elif is_integer(i):
if i >= len(ax):
raise IndexError(
f"{self.name} cannot enlarge its target object"
)
elif isinstance(i, dict):
raise IndexError(f"{self.name} cannot enlarge its target object")
return True
def _setitem_with_indexer(self, indexer, value):
self._has_valid_setitem_indexer(indexer)
# also has the side effect of consolidating in-place
from pandas import Series
info_axis = self.obj._info_axis_number
# maybe partial set
take_split_path = self.obj._is_mixed_type
# if there is only one block/type, still have to take split path
# unless the block is one-dimensional or it can hold the value
if not take_split_path and self.obj._data.blocks:
(blk,) = self.obj._data.blocks
if 1 < blk.ndim: # in case of dict, keys are indices
val = list(value.values()) if isinstance(value, dict) else value
take_split_path = not blk._can_hold_element(val)
# if we have any multi-indexes that have non-trivial slices
# (not null slices) then we must take the split path, xref
# GH 10360, GH 27841
if isinstance(indexer, tuple) and len(indexer) == len(self.obj.axes):
for i, ax in zip(indexer, self.obj.axes):
if isinstance(ax, ABCMultiIndex) and not (
is_integer(i) or com.is_null_slice(i)
):
take_split_path = True
break
if isinstance(indexer, tuple):
nindexer = []
for i, idx in enumerate(indexer):
if isinstance(idx, dict):
# reindex the axis to the new value
# and set inplace
key, _ = convert_missing_indexer(idx)
# if this is the items axes, then take the main missing
# path first
# this correctly sets the dtype and avoids cache issues
# essentially this separates out the block that is needed
# to possibly be modified
if self.ndim > 1 and i == self.obj._info_axis_number:
# add the new item, and set the value
# must have all defined axes if we have a scalar
# or a list-like on the non-info axes if we have a
# list-like
len_non_info_axes = (
len(_ax) for _i, _ax in enumerate(self.obj.axes) if _i != i
)
if any(not l for l in len_non_info_axes):
if not is_list_like_indexer(value):
raise ValueError(
"cannot set a frame with no "
"defined index and a scalar"
)
self.obj[key] = value
return self.obj
# add a new item with the dtype setup
self.obj[key] = _infer_fill_value(value)
new_indexer = convert_from_missing_indexer_tuple(
indexer, self.obj.axes
)
self._setitem_with_indexer(new_indexer, value)
return self.obj
# reindex the axis
# make sure to clear the cache because we are
# just replacing the block manager here
# so the object is the same
index = self.obj._get_axis(i)
labels = index.insert(len(index), key)
self.obj._data = self.obj.reindex(labels, axis=i)._data
self.obj._maybe_update_cacher(clear=True)
self.obj._is_copy = None
nindexer.append(labels.get_loc(key))
else:
nindexer.append(idx)
indexer = tuple(nindexer)
else:
indexer, missing = convert_missing_indexer(indexer)
if missing:
return self._setitem_with_indexer_missing(indexer, value)
# set
item_labels = self.obj._get_axis(info_axis)
# align and set the values
if take_split_path:
# Above we only set take_split_path to True for 2D cases
assert self.ndim == 2
assert info_axis == 1
if not isinstance(indexer, tuple):
indexer = _tuplify(self.ndim, indexer)
if isinstance(value, ABCSeries):
value = self._align_series(indexer, value)
info_idx = indexer[info_axis]
if is_integer(info_idx):
info_idx = [info_idx]
labels = item_labels[info_idx]
# if we have a partial multiindex, then need to adjust the plane
# indexer here
if len(labels) == 1 and isinstance(
self.obj[labels[0]].axes[0], ABCMultiIndex
):
item = labels[0]
obj = self.obj[item]
index = obj.index
idx = indexer[:info_axis][0]
plane_indexer = tuple([idx]) + indexer[info_axis + 1 :]
lplane_indexer = length_of_indexer(plane_indexer[0], index)
# require that we are setting the right number of values that
# we are indexing
if (
is_list_like_indexer(value)
and np.iterable(value)
and lplane_indexer != len(value)
):
if len(obj[idx]) != len(value):
raise ValueError(
"cannot set using a multi-index "
"selection indexer with a different "
"length than the value"
)
# make sure we have an ndarray
value = getattr(value, "values", value).ravel()
# we can directly set the series here
# as we select a slice indexer on the mi
if isinstance(idx, slice):
idx = index._convert_slice_indexer(idx)
obj._consolidate_inplace()
obj = obj.copy()
obj._data = obj._data.setitem(indexer=tuple([idx]), value=value)
self.obj[item] = obj
return
# non-mi
else:
plane_indexer = indexer[:info_axis] + indexer[info_axis + 1 :]
plane_axis = self.obj.axes[:info_axis][0]
lplane_indexer = length_of_indexer(plane_indexer[0], plane_axis)
def setter(item, v):
s = self.obj[item]
pi = plane_indexer[0] if lplane_indexer == 1 else plane_indexer
# perform the equivalent of a setitem on the info axis
# as we have a null slice or a slice with full bounds
# which means essentially reassign to the columns of a
# multi-dim object
# GH6149 (null slice), GH10408 (full bounds)
if isinstance(pi, tuple) and all(
com.is_null_slice(idx) or com.is_full_slice(idx, len(self.obj))
for idx in pi
):
s = v
else:
# set the item, possibly having a dtype change
s._consolidate_inplace()
s = s.copy()
s._data = s._data.setitem(indexer=pi, value=v)
s._maybe_update_cacher(clear=True)
# reset the sliced object if unique
self.obj[item] = s
# we need an iterable, with a ndim of at least 1
# eg. don't pass through np.array(0)
if is_list_like_indexer(value) and getattr(value, "ndim", 1) > 0:
# we have an equal len Frame
if isinstance(value, ABCDataFrame):
sub_indexer = list(indexer)
multiindex_indexer = isinstance(labels, ABCMultiIndex)
for item in labels:
if item in value:
sub_indexer[info_axis] = item
v = self._align_series(
tuple(sub_indexer), value[item], multiindex_indexer
)
else:
v = np.nan
setter(item, v)
# we have an equal len ndarray/convertible to our labels
# hasattr first, to avoid coercing to ndarray without reason.
# But we may be relying on the ndarray coercion to check ndim.
# Why not just convert to an ndarray earlier on if needed?
elif np.ndim(value) == 2:
# note that this coerces the dtype if we are mixed
# GH 7551
value = np.array(value, dtype=object)
if len(labels) != value.shape[1]:
raise ValueError(
"Must have equal len keys and value "
"when setting with an ndarray"
)
for i, item in enumerate(labels):
# setting with a list, recoerces
setter(item, value[:, i].tolist())
# we have an equal len list/ndarray
elif _can_do_equal_len(
labels, value, plane_indexer, lplane_indexer, self.obj
):
setter(labels[0], value)
# per label values
else:
if len(labels) != len(value):
raise ValueError(
"Must have equal len keys and value "
"when setting with an iterable"
)
for item, v in zip(labels, value):
setter(item, v)
else:
# scalar
for item in labels:
setter(item, value)
else:
if isinstance(indexer, tuple):
indexer = maybe_convert_ix(*indexer)
# if we are setting on the info axis ONLY
# set using those methods to avoid block-splitting
# logic here
if (
len(indexer) > info_axis
and is_integer(indexer[info_axis])
and all(
com.is_null_slice(idx)
for i, idx in enumerate(indexer)
if i != info_axis
)
and item_labels.is_unique
):
self.obj[item_labels[indexer[info_axis]]] = value
return
if isinstance(value, (ABCSeries, dict)):
# TODO(EA): ExtensionBlock.setitem this causes issues with
# setting for extensionarrays that store dicts. Need to decide
# if it's worth supporting that.
value = self._align_series(indexer, Series(value))
elif isinstance(value, ABCDataFrame):
value = self._align_frame(indexer, value)
# check for chained assignment
self.obj._check_is_chained_assignment_possible()
# actually do the set
self.obj._consolidate_inplace()
self.obj._data = self.obj._data.setitem(indexer=indexer, value=value)
self.obj._maybe_update_cacher(clear=True)
def _setitem_with_indexer_missing(self, indexer, value):
"""
Insert new row(s) or column(s) into the Series or DataFrame.
"""
from pandas import Series
# reindex the axis to the new value
# and set inplace
if self.ndim == 1:
index = self.obj.index
new_index = index.insert(len(index), indexer)
# we have a coerced indexer, e.g. a float
# that matches in an Int64Index, so
# we will not create a duplicate index, rather
# index to that element
# e.g. 0.0 -> 0
# GH#12246
if index.is_unique:
new_indexer = index.get_indexer([new_index[-1]])
if (new_indexer != -1).any():
return self._setitem_with_indexer(new_indexer, value)
# this preserves dtype of the value
new_values = Series([value])._values
if len(self.obj._values):
# GH#22717 handle casting compatibility that np.concatenate
# does incorrectly
new_values = concat_compat([self.obj._values, new_values])
self.obj._data = self.obj._constructor(
new_values, index=new_index, name=self.obj.name
)._data
self.obj._maybe_update_cacher(clear=True)
return self.obj
elif self.ndim == 2:
if not len(self.obj.columns):
# no columns and scalar
raise ValueError("cannot set a frame with no defined columns")
if isinstance(value, ABCSeries):
# append a Series
value = value.reindex(index=self.obj.columns, copy=True)
value.name = indexer
else:
# a list-list
if is_list_like_indexer(value):
# must have conforming columns
if len(value) != len(self.obj.columns):
raise ValueError("cannot set a row with mismatched columns")
value = Series(value, index=self.obj.columns, name=indexer)
self.obj._data = self.obj.append(value)._data
self.obj._maybe_update_cacher(clear=True)
return self.obj
def _align_series(self, indexer, ser: ABCSeries, multiindex_indexer: bool = False):
"""
Parameters
----------
indexer : tuple, slice, scalar
Indexer used to get the locations that will be set to `ser`.
ser : pd.Series
Values to assign to the locations specified by `indexer`.
multiindex_indexer : boolean, optional
Defaults to False. Should be set to True if `indexer` was from
a `pd.MultiIndex`, to avoid unnecessary broadcasting.
Returns
-------
`np.array` of `ser` broadcast to the appropriate shape for assignment
to the locations selected by `indexer`
"""
if isinstance(indexer, (slice, np.ndarray, list, Index)):
indexer = tuple([indexer])
if isinstance(indexer, tuple):
# flatten np.ndarray indexers
def ravel(i):
return i.ravel() if isinstance(i, np.ndarray) else i
indexer = tuple(map(ravel, indexer))
aligners = [not com.is_null_slice(idx) for idx in indexer]
sum_aligners = sum(aligners)
single_aligner = sum_aligners == 1
is_frame = self.ndim == 2
obj = self.obj
# are we a single alignable value on a non-primary
# dim (e.g. panel: 1,2, or frame: 0) ?
# hence need to align to a single axis dimension
# rather that find all valid dims
# frame
if is_frame:
single_aligner = single_aligner and aligners[0]
# we have a frame, with multiple indexers on both axes; and a
# series, so need to broadcast (see GH5206)
if sum_aligners == self.ndim and all(is_sequence(_) for _ in indexer):
ser = ser.reindex(obj.axes[0][indexer[0]], copy=True)._values
# single indexer
if len(indexer) > 1 and not multiindex_indexer:
len_indexer = len(indexer[1])
ser = np.tile(ser, len_indexer).reshape(len_indexer, -1).T
return ser
for i, idx in enumerate(indexer):
ax = obj.axes[i]
# multiple aligners (or null slices)
if is_sequence(idx) or isinstance(idx, slice):
if single_aligner and com.is_null_slice(idx):
continue
new_ix = ax[idx]
if not is_list_like_indexer(new_ix):
new_ix = Index([new_ix])
else:
new_ix = Index(new_ix)
if ser.index.equals(new_ix) or not len(new_ix):
return ser._values.copy()
return ser.reindex(new_ix)._values
# 2 dims
elif single_aligner:
# reindex along index
ax = self.obj.axes[1]
if ser.index.equals(ax) or not len(ax):
return ser._values.copy()
return ser.reindex(ax)._values
elif is_scalar(indexer):
ax = self.obj._get_axis(1)
if ser.index.equals(ax):
return ser._values.copy()
return ser.reindex(ax)._values
raise ValueError("Incompatible indexer with Series")
def _align_frame(self, indexer, df: ABCDataFrame):
is_frame = self.ndim == 2
if isinstance(indexer, tuple):
idx, cols = None, None
sindexers = []
for i, ix in enumerate(indexer):
ax = self.obj.axes[i]
if is_sequence(ix) or isinstance(ix, slice):
if isinstance(ix, np.ndarray):
ix = ix.ravel()
if idx is None:
idx = ax[ix]
elif cols is None:
cols = ax[ix]
else:
break
else:
sindexers.append(i)
if idx is not None and cols is not None:
if df.index.equals(idx) and df.columns.equals(cols):
val = df.copy()._values
else:
val = df.reindex(idx, columns=cols)._values
return val
elif (isinstance(indexer, slice) or is_list_like_indexer(indexer)) and is_frame:
ax = self.obj.index[indexer]
if df.index.equals(ax):
val = df.copy()._values
else:
# we have a multi-index and are trying to align
# with a particular, level GH3738
if (
isinstance(ax, ABCMultiIndex)
and isinstance(df.index, ABCMultiIndex)
and ax.nlevels != df.index.nlevels
):
raise TypeError(
"cannot align on a multi-index with out "
"specifying the join levels"
)
val = df.reindex(index=ax)._values
return val
raise ValueError("Incompatible indexer with DataFrame")
def _getitem_tuple(self, tup: Tuple):
try:
return self._getitem_lowerdim(tup)
except IndexingError:
pass
# no multi-index, so validate all of the indexers
self._has_valid_tuple(tup)
# ugly hack for GH #836
if self._multi_take_opportunity(tup):
return self._multi_take(tup)
# no shortcut needed
retval = self.obj
for i, key in enumerate(tup):
if com.is_null_slice(key):
continue
retval = getattr(retval, self.name)._getitem_axis(key, axis=i)
return retval
def _multi_take_opportunity(self, tup: Tuple) -> bool:
"""
Check whether there is the possibility to use ``_multi_take``.
Currently the limit is that all axes being indexed, must be indexed with
list-likes.
Parameters
----------
tup : tuple
Tuple of indexers, one per axis.
Returns
-------
bool
Whether the current indexing,
can be passed through `_multi_take`.
"""
if not all(is_list_like_indexer(x) for x in tup):
return False
# just too complicated
if any(com.is_bool_indexer(x) for x in tup):
return False
return True
def _multi_take(self, tup: Tuple):
"""
Create the indexers for the passed tuple of keys, and
executes the take operation. This allows the take operation to be
executed all at once, rather than once for each dimension.
Improving efficiency.
Parameters
----------
tup : tuple
Tuple of indexers, one per axis.
Returns
-------
values: same type as the object being indexed
"""
# GH 836
o = self.obj
d = {
axis: self._get_listlike_indexer(key, axis)
for (key, axis) in zip(tup, o._AXIS_ORDERS)
}
return o._reindex_with_indexers(d, copy=True, allow_dups=True)
def _handle_lowerdim_multi_index_axis0(self, tup: Tuple):
# we have an axis0 multi-index, handle or raise
axis = self.axis or 0
try:
# fast path for series or for tup devoid of slices
return self._get_label(tup, axis=axis)
except TypeError:
# slices are unhashable
pass
except KeyError as ek:
# raise KeyError if number of indexers match
# else IndexingError will be raised
if len(tup) <= self.obj.index.nlevels and len(tup) > self.ndim:
raise ek
return None
def _getitem_lowerdim(self, tup: Tuple):
# we can directly get the axis result since the axis is specified
if self.axis is not None:
axis = self.obj._get_axis_number(self.axis)
return self._getitem_axis(tup, axis=axis)
# we may have a nested tuples indexer here
if self._is_nested_tuple_indexer(tup):
return self._getitem_nested_tuple(tup)
# we maybe be using a tuple to represent multiple dimensions here
ax0 = self.obj._get_axis(0)
# ...but iloc should handle the tuple as simple integer-location
# instead of checking it as multiindex representation (GH 13797)
if isinstance(ax0, ABCMultiIndex) and self.name != "iloc":
result = self._handle_lowerdim_multi_index_axis0(tup)
if result is not None:
return result
if len(tup) > self.ndim:
raise IndexingError("Too many indexers. handle elsewhere")
for i, key in enumerate(tup):
if is_label_like(key) or isinstance(key, tuple):
section = self._getitem_axis(key, axis=i)
# we have yielded a scalar ?
if not is_list_like_indexer(section):
return section
elif section.ndim == self.ndim:
# we're in the middle of slicing through a MultiIndex
# revise the key wrt to `section` by inserting an _NS
new_key = tup[:i] + (_NS,) + tup[i + 1 :]
else:
new_key = tup[:i] + tup[i + 1 :]
# unfortunately need an odious kludge here because of
# DataFrame transposing convention
if (
isinstance(section, ABCDataFrame)
and i > 0
and len(new_key) == 2
):
a, b = new_key
new_key = b, a
if len(new_key) == 1:
new_key = new_key[0]
# Slices should return views, but calling iloc/loc with a null
# slice returns a new object.
if com.is_null_slice(new_key):
return section
# This is an elided recursive call to iloc/loc/etc'
return getattr(section, self.name)[new_key]
raise IndexingError("not applicable")
def _getitem_nested_tuple(self, tup: Tuple):
# we have a nested tuple so have at least 1 multi-index level
# we should be able to match up the dimensionality here
# we have too many indexers for our dim, but have at least 1
# multi-index dimension, try to see if we have something like
# a tuple passed to a series with a multi-index
if len(tup) > self.ndim:
result = self._handle_lowerdim_multi_index_axis0(tup)
if result is not None:
return result
# this is a series with a multi-index specified a tuple of
# selectors
axis = self.axis or 0
return self._getitem_axis(tup, axis=axis)
# handle the multi-axis by taking sections and reducing
# this is iterative
obj = self.obj
axis = 0
for i, key in enumerate(tup):
if com.is_null_slice(key):
axis += 1
continue
current_ndim = obj.ndim
obj = getattr(obj, self.name)._getitem_axis(key, axis=axis)
axis += 1
# if we have a scalar, we are done
if is_scalar(obj) or not hasattr(obj, "ndim"):
break
# has the dim of the obj changed?
# GH 7199
if obj.ndim < current_ndim:
axis -= 1
return obj
def _get_listlike_indexer(self, key, axis: int, raise_missing: bool = False):
"""
Transform a list-like of keys into a new index and an indexer.
Parameters
----------
key : list-like
Targeted labels.
axis: int
Dimension on which the indexing is being made.
raise_missing: bool, default False
Whether to raise a KeyError if some labels were not found.
Will be removed in the future, and then this method will always behave as
if ``raise_missing=True``.
Raises
------
KeyError
If at least one key was requested but none was found, and
raise_missing=True.
Returns
-------
keyarr: Index
New index (coinciding with 'key' if the axis is unique).
values : array-like
Indexer for the return object, -1 denotes keys not found.
"""
o = self.obj
ax = o._get_axis(axis)
# Have the index compute an indexer or return None
# if it cannot handle:
assert self.name == "loc"
indexer, keyarr = ax._convert_listlike_indexer(key)
# We only act on all found values:
if indexer is not None and (indexer != -1).all():
self._validate_read_indexer(key, indexer, axis, raise_missing=raise_missing)
return ax[indexer], indexer
if ax.is_unique and not getattr(ax, "is_overlapping", False):
indexer = ax.get_indexer_for(key)
keyarr = ax.reindex(keyarr)[0]
else:
keyarr, indexer, new_indexer = ax._reindex_non_unique(keyarr)
self._validate_read_indexer(keyarr, indexer, axis, raise_missing=raise_missing)
return keyarr, indexer
def _getitem_iterable(self, key, axis: int):
"""
Index current object with an an iterable collection of keys.
Parameters
----------
key : iterable
Targeted labels.
axis: int
Dimension on which the indexing is being made.
Raises
------
KeyError
If no key was found. Will change in the future to raise if not all
keys were found.
Returns
-------
scalar, DataFrame, or Series: indexed value(s).
"""
# we assume that not com.is_bool_indexer(key), as that is
# handled before we get here.
self._validate_key(key, axis)
# A collection of keys
keyarr, indexer = self._get_listlike_indexer(key, axis, raise_missing=False)
return self.obj._reindex_with_indexers(
{axis: [keyarr, indexer]}, copy=True, allow_dups=True
)
def _validate_read_indexer(
self, key, indexer, axis: int, raise_missing: bool = False
):
"""
Check that indexer can be used to return a result.
e.g. at least one element was found,
unless the list of keys was actually empty.
Parameters
----------
key : list-like
Targeted labels (only used to show correct error message).
indexer: array-like of booleans
Indices corresponding to the key,
(with -1 indicating not found).
axis: int
Dimension on which the indexing is being made.
raise_missing: bool
Whether to raise a KeyError if some labels are not found. Will be
removed in the future, and then this method will always behave as
if raise_missing=True.
Raises
------
KeyError
If at least one key was requested but none was found, and
raise_missing=True.
"""
ax = self.obj._get_axis(axis)
if len(key) == 0:
return
# Count missing values:
missing = (indexer < 0).sum()
if missing:
if missing == len(indexer):
axis_name = self.obj._get_axis_name(axis)
raise KeyError(f"None of [{key}] are in the [{axis_name}]")
# We (temporarily) allow for some missing keys with .loc, except in
# some cases (e.g. setting) in which "raise_missing" will be False
if not (self.name == "loc" and not raise_missing):
not_found = list(set(key) - set(ax))
raise KeyError(f"{not_found} not in index")
# we skip the warning on Categorical/Interval
# as this check is actually done (check for
# non-missing values), but a bit later in the
# code, so we want to avoid warning & then
# just raising
if not (ax.is_categorical() or ax.is_interval()):
raise KeyError(
"Passing list-likes to .loc or [] with any missing labels "
"is no longer supported, see "
"https://pandas.pydata.org/pandas-docs/stable/user_guide/indexing.html#deprecate-loc-reindex-listlike" # noqa:E501
)
def _convert_to_indexer(self, key, axis: int, is_setter: bool = False):
raise AbstractMethodError(self)
def __getitem__(self, key):
if type(key) is tuple:
key = tuple(com.apply_if_callable(x, self.obj) for x in key)
if self._is_scalar_access(key):
try:
return self.obj._get_value(*key, takeable=self._takeable)
except (KeyError, IndexError, AttributeError):
# AttributeError for IntervalTree get_value
pass
return self._getitem_tuple(key)
else:
# we by definition only have the 0th axis
axis = self.axis or 0
maybe_callable = com.apply_if_callable(key, self.obj)
return self._getitem_axis(maybe_callable, axis=axis)
def _is_scalar_access(self, key: Tuple):
raise NotImplementedError()
def _getitem_axis(self, key, axis: int):
raise NotImplementedError()
def _getbool_axis(self, key, axis: int):
# caller is responsible for ensuring non-None axis
labels = self.obj._get_axis(axis)
key = check_bool_indexer(labels, key)
inds = key.nonzero()[0]
return self.obj._take_with_is_copy(inds, axis=axis)
@Appender(IndexingMixin.loc.__doc__)
class _LocIndexer(_LocationIndexer):
_takeable: bool = False
_valid_types = (
"labels (MUST BE IN THE INDEX), slices of labels (BOTH "
"endpoints included! Can be slices of integers if the "
"index is integers), listlike of labels, boolean"
)
@Appender(_LocationIndexer._validate_key.__doc__)
def _validate_key(self, key, axis: int):
# valid for a collection of labels (we check their presence later)
# slice of labels (where start-end in labels)
# slice of integers (only if in the labels)
# boolean
if isinstance(key, slice):
return
if com.is_bool_indexer(key):
return
if not is_list_like_indexer(key):
labels = self.obj._get_axis(axis)
labels._convert_scalar_indexer(key, kind="loc")
def _is_scalar_access(self, key: Tuple) -> bool:
"""
Returns
-------
bool
"""
# this is a shortcut accessor to both .loc and .iloc
# that provide the equivalent access of .at and .iat
# a) avoid getting things via sections and (to minimize dtype changes)
# b) provide a performant path
if len(key) != self.ndim:
return False
for i, k in enumerate(key):
if not is_scalar(k):
return False
ax = self.obj.axes[i]
if isinstance(ax, ABCMultiIndex):
return False
if isinstance(k, str) and ax._supports_partial_string_indexing:
# partial string indexing, df.loc['2000', 'A']
# should not be considered scalar
return False
if not ax.is_unique:
return False
return True
def _get_partial_string_timestamp_match_key(self, key, labels):
"""
Translate any partial string timestamp matches in key, returning the
new key.
(GH 10331)
"""
if isinstance(labels, ABCMultiIndex):
if (
isinstance(key, str)
and labels.levels[0]._supports_partial_string_indexing
):
# Convert key '2016-01-01' to
# ('2016-01-01'[, slice(None, None, None)]+)
key = tuple([key] + [slice(None)] * (len(labels.levels) - 1))
if isinstance(key, tuple):
# Convert (..., '2016-01-01', ...) in tuple to
# (..., slice('2016-01-01', '2016-01-01', None), ...)
new_key = []
for i, component in enumerate(key):
if (
isinstance(component, str)
and labels.levels[i]._supports_partial_string_indexing
):
new_key.append(slice(component, component, None))
else:
new_key.append(component)
key = tuple(new_key)
return key
def _getitem_axis(self, key, axis: int):
key = item_from_zerodim(key)
if is_iterator(key):
key = list(key)
labels = self.obj._get_axis(axis)
key = self._get_partial_string_timestamp_match_key(key, labels)
if isinstance(key, slice):
self._validate_key(key, axis)
return self._get_slice_axis(key, axis=axis)
elif com.is_bool_indexer(key):
return self._getbool_axis(key, axis=axis)
elif is_list_like_indexer(key):
# convert various list-like indexers
# to a list of keys
# we will use the *values* of the object
# and NOT the index if its a PandasObject
if isinstance(labels, ABCMultiIndex):
if isinstance(key, (ABCSeries, np.ndarray)) and key.ndim <= 1:
# Series, or 0,1 ndim ndarray
# GH 14730
key = list(key)
elif isinstance(key, ABCDataFrame):
# GH 15438
raise NotImplementedError(
"Indexing a MultiIndex with a "
"DataFrame key is not "
"implemented"
)
elif hasattr(key, "ndim") and key.ndim > 1:
raise NotImplementedError(
"Indexing a MultiIndex with a "
"multidimensional key is not "
"implemented"
)
if (
not isinstance(key, tuple)
and len(key)
and not isinstance(key[0], tuple)
):
key = tuple([key])
# an iterable multi-selection
if not (isinstance(key, tuple) and isinstance(labels, ABCMultiIndex)):
if hasattr(key, "ndim") and key.ndim > 1:
raise ValueError("Cannot index with multidimensional key")
return self._getitem_iterable(key, axis=axis)
# nested tuple slicing
if is_nested_tuple(key, labels):
locs = labels.get_locs(key)
indexer = [slice(None)] * self.ndim
indexer[axis] = locs
return self.obj.iloc[tuple(indexer)]
# fall thru to straight lookup
self._validate_key(key, axis)
return self._get_label(key, axis=axis)
def _get_slice_axis(self, slice_obj: slice, axis: int):
"""
This is pretty simple as we just have to deal with labels.
"""
# caller is responsible for ensuring non-None axis
obj = self.obj
if not need_slice(slice_obj):
return obj.copy(deep=False)
labels = obj._get_axis(axis)
indexer = labels.slice_indexer(
slice_obj.start, slice_obj.stop, slice_obj.step, kind=self.name
)
if isinstance(indexer, slice):
return self.obj._slice(indexer, axis=axis, kind="iloc")
else:
# DatetimeIndex overrides Index.slice_indexer and may
# return a DatetimeIndex instead of a slice object.
return self.obj.take(indexer, axis=axis)
def _convert_to_indexer(self, key, axis: int, is_setter: bool = False):
"""
Convert indexing key into something we can use to do actual fancy
indexing on a ndarray.
Examples
ix[:5] -> slice(0, 5)
ix[[1,2,3]] -> [1,2,3]
ix[['foo', 'bar', 'baz']] -> [i, j, k] (indices of foo, bar, baz)
Going by Zen of Python?
'In the face of ambiguity, refuse the temptation to guess.'
raise AmbiguousIndexError with integer labels?
- No, prefer label-based indexing
"""
labels = self.obj._get_axis(axis)
if isinstance(key, slice):
return labels._convert_slice_indexer(key, kind="loc")
if is_scalar(key):
# try to find out correct indexer, if not type correct raise
try:
key = labels._convert_scalar_indexer(key, kind="loc")
except TypeError:
# but we will allow setting
if not is_setter:
raise
# see if we are positional in nature
is_int_index = labels.is_integer()
is_int_positional = is_integer(key) and not is_int_index
if is_scalar(key) or isinstance(labels, ABCMultiIndex):
# Otherwise get_loc will raise InvalidIndexError
# if we are a label return me
try:
return labels.get_loc(key)
except LookupError:
if isinstance(key, tuple) and isinstance(labels, ABCMultiIndex):
if len(key) == labels.nlevels:
return {"key": key}
raise
except TypeError:
pass
except ValueError:
if not is_int_positional:
raise
# a positional
if is_int_positional:
# if we are setting and its not a valid location
# its an insert which fails by definition
# always valid
return {"key": key}
if is_nested_tuple(key, labels):
return labels.get_locs(key)
elif is_list_like_indexer(key):
if com.is_bool_indexer(key):
key = check_bool_indexer(labels, key)
(inds,) = key.nonzero()
return inds
else:
# When setting, missing keys are not allowed, even with .loc:
return self._get_listlike_indexer(key, axis, raise_missing=True)[1]
else:
try:
return labels.get_loc(key)
except LookupError:
# allow a not found key only if we are a setter
if not is_list_like_indexer(key):
return {"key": key}
raise
@Appender(IndexingMixin.iloc.__doc__)
class _iLocIndexer(_LocationIndexer):
_valid_types = (
"integer, integer slice (START point is INCLUDED, END "
"point is EXCLUDED), listlike of integers, boolean array"
)
_takeable = True
def _validate_key(self, key, axis: int):
if com.is_bool_indexer(key):
if hasattr(key, "index") and isinstance(key.index, Index):
if key.index.inferred_type == "integer":
raise NotImplementedError(
"iLocation based boolean "
"indexing on an integer type "
"is not available"
)
raise ValueError(
"iLocation based boolean indexing cannot use "
"an indexable as a mask"
)
return
if isinstance(key, slice):
return
elif is_integer(key):
self._validate_integer(key, axis)
elif isinstance(key, tuple):
# a tuple should already have been caught by this point
# so don't treat a tuple as a valid indexer
raise IndexingError("Too many indexers")
elif is_list_like_indexer(key):
arr = np.array(key)
len_axis = len(self.obj._get_axis(axis))
# check that the key has a numeric dtype
if not is_numeric_dtype(arr.dtype):
raise IndexError(f".iloc requires numeric indexers, got {arr}")
# check that the key does not exceed the maximum size of the index
if len(arr) and (arr.max() >= len_axis or arr.min() < -len_axis):
raise IndexError("positional indexers are out-of-bounds")
else:
raise ValueError(f"Can only index by location with a [{self._valid_types}]")
def _has_valid_setitem_indexer(self, indexer):
self._has_valid_positional_setitem_indexer(indexer)
def _is_scalar_access(self, key: Tuple) -> bool:
"""
Returns
-------
bool
"""
# this is a shortcut accessor to both .loc and .iloc
# that provide the equivalent access of .at and .iat
# a) avoid getting things via sections and (to minimize dtype changes)
# b) provide a performant path
if len(key) != self.ndim:
return False
for i, k in enumerate(key):
if not is_integer(k):
return False
ax = self.obj.axes[i]
if not ax.is_unique:
return False
return True
def _validate_integer(self, key: int, axis: int) -> None:
"""
Check that 'key' is a valid position in the desired axis.
Parameters
----------
key : int
Requested position.
axis : int
Desired axis.
Raises
------
IndexError
If 'key' is not a valid position in axis 'axis'.
"""
len_axis = len(self.obj._get_axis(axis))
if key >= len_axis or key < -len_axis:
raise IndexError("single positional indexer is out-of-bounds")
def _getitem_tuple(self, tup: Tuple):
self._has_valid_tuple(tup)
try:
return self._getitem_lowerdim(tup)
except IndexingError:
pass
retval = self.obj
axis = 0
for i, key in enumerate(tup):
if com.is_null_slice(key):
axis += 1
continue
retval = getattr(retval, self.name)._getitem_axis(key, axis=axis)
# if the dim was reduced, then pass a lower-dim the next time
if retval.ndim < self.ndim:
# TODO: this is never reached in tests; can we confirm that
# it is impossible?
axis -= 1
# try to get for the next axis
axis += 1
return retval
def _get_list_axis(self, key, axis: int):
"""
Return Series values by list or array of integers.
Parameters
----------
key : list-like positional indexer
axis : int
Returns
-------
Series object
Notes
-----
`axis` can only be zero.
"""
try:
return self.obj._take_with_is_copy(key, axis=axis)
except IndexError:
# re-raise with different error message
raise IndexError("positional indexers are out-of-bounds")
def _getitem_axis(self, key, axis: int):
if isinstance(key, slice):
return self._get_slice_axis(key, axis=axis)
if isinstance(key, list):
key = np.asarray(key)
if com.is_bool_indexer(key):
self._validate_key(key, axis)
return self._getbool_axis(key, axis=axis)
# a list of integers
elif is_list_like_indexer(key):
return self._get_list_axis(key, axis=axis)
# a single integer
else:
key = item_from_zerodim(key)
if not is_integer(key):
raise TypeError("Cannot index by location index with a non-integer key")
# validate the location
self._validate_integer(key, axis)
return self.obj._ixs(key, axis=axis)
def _get_slice_axis(self, slice_obj: slice, axis: int):
# caller is responsible for ensuring non-None axis
obj = self.obj
if not need_slice(slice_obj):
return obj.copy(deep=False)
labels = obj._get_axis(axis)
indexer = labels._convert_slice_indexer(slice_obj, kind="iloc")
return self.obj._slice(indexer, axis=axis, kind="iloc")
def _convert_to_indexer(self, key, axis: int, is_setter: bool = False):
"""
Much simpler as we only have to deal with our valid types.
"""
labels = self.obj._get_axis(axis)
# make need to convert a float key
if isinstance(key, slice):
return labels._convert_slice_indexer(key, kind="iloc")
elif is_float(key):
return labels._convert_scalar_indexer(key, kind="iloc")
self._validate_key(key, axis)
return key
class _ScalarAccessIndexer(_NDFrameIndexerBase):
"""
Access scalars quickly.
"""
def _convert_key(self, key, is_setter: bool = False):
raise AbstractMethodError(self)
def __getitem__(self, key):
if not isinstance(key, tuple):
# we could have a convertible item here (e.g. Timestamp)
if not is_list_like_indexer(key):
key = tuple([key])
else:
raise ValueError("Invalid call for scalar access (getting)!")
key = self._convert_key(key)
return self.obj._get_value(*key, takeable=self._takeable)
def __setitem__(self, key, value):
if isinstance(key, tuple):
key = tuple(com.apply_if_callable(x, self.obj) for x in key)
else:
# scalar callable may return tuple
key = com.apply_if_callable(key, self.obj)
if not isinstance(key, tuple):
key = _tuplify(self.ndim, key)
if len(key) != self.ndim:
raise ValueError("Not enough indexers for scalar access (setting)!")
key = list(self._convert_key(key, is_setter=True))
self.obj._set_value(*key, value=value, takeable=self._takeable)
@Appender(IndexingMixin.at.__doc__)
class _AtIndexer(_ScalarAccessIndexer):
_takeable = False
def _convert_key(self, key, is_setter: bool = False):
"""
Require they keys to be the same type as the index. (so we don't
fallback)
"""
# allow arbitrary setting
if is_setter:
return list(key)
lkey = list(key)
for n, (ax, i) in enumerate(zip(self.obj.axes, key)):
lkey[n] = ax._convert_scalar_indexer(i, kind="loc")
return tuple(lkey)
@Appender(IndexingMixin.iat.__doc__)
class _iAtIndexer(_ScalarAccessIndexer):
_takeable = True
def _convert_key(self, key, is_setter: bool = False):
"""
Require integer args. (and convert to label arguments)
"""
for a, i in zip(self.obj.axes, key):
if not is_integer(i):
raise ValueError("iAt based indexing can only have integer indexers")
return key
def _tuplify(ndim: int, loc: Hashable) -> Tuple[Union[Hashable, slice], ...]:
"""
Given an indexer for the first dimension, create an equivalent tuple
for indexing over all dimensions.
Parameters
----------
ndim : int
loc : object
Returns
-------
tuple
"""
_tup: List[Union[Hashable, slice]]
_tup = [slice(None, None) for _ in range(ndim)]
_tup[0] = loc
return tuple(_tup)
def convert_to_index_sliceable(obj, key):
"""
If we are index sliceable, then return my slicer, otherwise return None.
"""
idx = obj.index
if isinstance(key, slice):
return idx._convert_slice_indexer(key, kind="getitem")
elif isinstance(key, str):
# we are an actual column
if key in obj._data.items:
return None
# We might have a datetimelike string that we can translate to a
# slice here via partial string indexing
if idx._supports_partial_string_indexing:
try:
return idx._get_string_slice(key)
except (KeyError, ValueError, NotImplementedError):
return None
return None
def check_bool_indexer(index: Index, key) -> np.ndarray:
"""
Check if key is a valid boolean indexer for an object with such index and
perform reindexing or conversion if needed.
This function assumes that is_bool_indexer(key) == True.
Parameters
----------
index : Index
Index of the object on which the indexing is done.
key : list-like
Boolean indexer to check.
Returns
-------
np.array
Resulting key.
Raises
------
IndexError
If the key does not have the same length as index.
IndexingError
If the index of the key is unalignable to index.
"""
result = key
if isinstance(key, ABCSeries) and not key.index.equals(index):
result = result.reindex(index)
mask = isna(result._values)
if mask.any():
raise IndexingError(
"Unalignable boolean Series provided as "
"indexer (index of the boolean Series and of "
"the indexed object do not match)."
)
result = result.astype(bool)._values
else:
# key might be sparse / object-dtype bool, check_array_indexer needs bool array
result = np.asarray(result, dtype=bool)
result = check_array_indexer(index, result)
return result
def convert_missing_indexer(indexer):
"""
Reverse convert a missing indexer, which is a dict
return the scalar indexer and a boolean indicating if we converted
"""
if isinstance(indexer, dict):
# a missing key (but not a tuple indexer)
indexer = indexer["key"]
if isinstance(indexer, bool):
raise KeyError("cannot use a single bool to index into setitem")
return indexer, True
return indexer, False
def convert_from_missing_indexer_tuple(indexer, axes):
"""
Create a filtered indexer that doesn't have any missing indexers.
"""
def get_indexer(_i, _idx):
return axes[_i].get_loc(_idx["key"]) if isinstance(_idx, dict) else _idx
return tuple(get_indexer(_i, _idx) for _i, _idx in enumerate(indexer))
def maybe_convert_ix(*args):
"""
We likely want to take the cross-product.
"""
ixify = True
for arg in args:
if not isinstance(arg, (np.ndarray, list, ABCSeries, Index)):
ixify = False
if ixify:
return np.ix_(*args)
else:
return args
def is_nested_tuple(tup, labels) -> bool:
"""
Returns
-------
bool
"""
# check for a compatible nested tuple and multiindexes among the axes
if not isinstance(tup, tuple):
return False
for i, k in enumerate(tup):
if is_list_like(k) or isinstance(k, slice):
return isinstance(labels, ABCMultiIndex)
return False
def is_label_like(key) -> bool:
"""
Returns
-------
bool
"""
# select a label or row
return not isinstance(key, slice) and not is_list_like_indexer(key)
def need_slice(obj) -> bool:
"""
Returns
-------
bool
"""
return (
obj.start is not None
or obj.stop is not None
or (obj.step is not None and obj.step != 1)
)
def _non_reducing_slice(slice_):
"""
Ensurse that a slice doesn't reduce to a Series or Scalar.
Any user-paseed `subset` should have this called on it
to make sure we're always working with DataFrames.
"""
# default to column slice, like DataFrame
# ['A', 'B'] -> IndexSlices[:, ['A', 'B']]
kinds = (ABCSeries, np.ndarray, Index, list, str)
if isinstance(slice_, kinds):
slice_ = IndexSlice[:, slice_]
def pred(part) -> bool:
"""
Returns
-------
bool
True if slice does *not* reduce,
False if `part` is a tuple.
"""
# true when slice does *not* reduce, False when part is a tuple,
# i.e. MultiIndex slice
return (isinstance(part, slice) or is_list_like(part)) and not isinstance(
part, tuple
)
if not is_list_like(slice_):
if not isinstance(slice_, slice):
# a 1-d slice, like df.loc[1]
slice_ = [[slice_]]
else:
# slice(a, b, c)
slice_ = [slice_] # to tuplize later
else:
slice_ = [part if pred(part) else [part] for part in slice_]
return tuple(slice_)
def _maybe_numeric_slice(df, slice_, include_bool=False):
"""
Want nice defaults for background_gradient that don't break
with non-numeric data. But if slice_ is passed go with that.
"""
if slice_ is None:
dtypes = [np.number]
if include_bool:
dtypes.append(bool)
slice_ = IndexSlice[:, df.select_dtypes(include=dtypes).columns]
return slice_
def _can_do_equal_len(labels, value, plane_indexer, lplane_indexer, obj) -> bool:
"""
Returns
-------
bool
True if we have an equal len settable.
"""
if not len(labels) == 1 or not np.iterable(value) or is_scalar(plane_indexer[0]):
return False
item = labels[0]
index = obj[item].index
values_len = len(value)
# equal len list/ndarray
if len(index) == values_len:
return True
elif lplane_indexer == values_len:
return True
return False
| BugsInPy/BugsInPy/temp/projects/pandas/bug-63-fixed/pandas/pandas/core/indexing.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-63-buggy/pandas/pandas/core/indexing.py |
pandas-bug-46 | from sys import getsizeof
from typing import (
TYPE_CHECKING,
Any,
Hashable,
Iterable,
List,
Optional,
Sequence,
Tuple,
Union,
)
import warnings
import numpy as np
from pandas._config import get_option
from pandas._libs import algos as libalgos, index as libindex, lib
from pandas._libs.hashtable import duplicated_int64
from pandas._typing import AnyArrayLike, Scalar
from pandas.compat.numpy import function as nv
from pandas.errors import PerformanceWarning, UnsortedIndexError
from pandas.util._decorators import Appender, cache_readonly
from pandas.core.dtypes.cast import coerce_indexer_dtype
from pandas.core.dtypes.common import (
ensure_int64,
ensure_platform_int,
is_categorical_dtype,
is_hashable,
is_integer,
is_iterator,
is_list_like,
is_object_dtype,
is_scalar,
pandas_dtype,
)
from pandas.core.dtypes.dtypes import ExtensionDtype
from pandas.core.dtypes.generic import ABCDataFrame
from pandas.core.dtypes.missing import array_equivalent, isna
import pandas.core.algorithms as algos
from pandas.core.arrays import Categorical
from pandas.core.arrays.categorical import factorize_from_iterables
import pandas.core.common as com
import pandas.core.indexes.base as ibase
from pandas.core.indexes.base import (
Index,
InvalidIndexError,
_index_shared_docs,
ensure_index,
)
from pandas.core.indexes.frozen import FrozenList
from pandas.core.indexes.numeric import Int64Index
import pandas.core.missing as missing
from pandas.core.sorting import (
get_group_index,
indexer_from_factorized,
lexsort_indexer,
)
from pandas.io.formats.printing import (
format_object_attrs,
format_object_summary,
pprint_thing,
)
if TYPE_CHECKING:
from pandas import Series # noqa:F401
_index_doc_kwargs = dict(ibase._index_doc_kwargs)
_index_doc_kwargs.update(
dict(klass="MultiIndex", target_klass="MultiIndex or list of tuples")
)
class MultiIndexUIntEngine(libindex.BaseMultiIndexCodesEngine, libindex.UInt64Engine):
"""
This class manages a MultiIndex by mapping label combinations to positive
integers.
"""
_base = libindex.UInt64Engine
def _codes_to_ints(self, codes):
"""
Transform combination(s) of uint64 in one uint64 (each), in a strictly
monotonic way (i.e. respecting the lexicographic order of integer
combinations): see BaseMultiIndexCodesEngine documentation.
Parameters
----------
codes : 1- or 2-dimensional array of dtype uint64
Combinations of integers (one per row)
Returns
-------
scalar or 1-dimensional array, of dtype uint64
Integer(s) representing one combination (each).
"""
# Shift the representation of each level by the pre-calculated number
# of bits:
codes <<= self.offsets
# Now sum and OR are in fact interchangeable. This is a simple
# composition of the (disjunct) significant bits of each level (i.e.
# each column in "codes") in a single positive integer:
if codes.ndim == 1:
# Single key
return np.bitwise_or.reduce(codes)
# Multiple keys
return np.bitwise_or.reduce(codes, axis=1)
class MultiIndexPyIntEngine(libindex.BaseMultiIndexCodesEngine, libindex.ObjectEngine):
"""
This class manages those (extreme) cases in which the number of possible
label combinations overflows the 64 bits integers, and uses an ObjectEngine
containing Python integers.
"""
_base = libindex.ObjectEngine
def _codes_to_ints(self, codes):
"""
Transform combination(s) of uint64 in one Python integer (each), in a
strictly monotonic way (i.e. respecting the lexicographic order of
integer combinations): see BaseMultiIndexCodesEngine documentation.
Parameters
----------
codes : 1- or 2-dimensional array of dtype uint64
Combinations of integers (one per row)
Returns
-------
int, or 1-dimensional array of dtype object
Integer(s) representing one combination (each).
"""
# Shift the representation of each level by the pre-calculated number
# of bits. Since this can overflow uint64, first make sure we are
# working with Python integers:
codes = codes.astype("object") << self.offsets
# Now sum and OR are in fact interchangeable. This is a simple
# composition of the (disjunct) significant bits of each level (i.e.
# each column in "codes") in a single positive integer (per row):
if codes.ndim == 1:
# Single key
return np.bitwise_or.reduce(codes)
# Multiple keys
return np.bitwise_or.reduce(codes, axis=1)
class MultiIndex(Index):
"""
A multi-level, or hierarchical, index object for pandas objects.
Parameters
----------
levels : sequence of arrays
The unique labels for each level.
codes : sequence of arrays
Integers for each level designating which label at each location.
.. versionadded:: 0.24.0
sortorder : optional int
Level of sortedness (must be lexicographically sorted by that
level).
names : optional sequence of objects
Names for each of the index levels. (name is accepted for compat).
copy : bool, default False
Copy the meta-data.
verify_integrity : bool, default True
Check that the levels/codes are consistent and valid.
Attributes
----------
names
levels
codes
nlevels
levshape
Methods
-------
from_arrays
from_tuples
from_product
from_frame
set_levels
set_codes
to_frame
to_flat_index
is_lexsorted
sortlevel
droplevel
swaplevel
reorder_levels
remove_unused_levels
get_locs
See Also
--------
MultiIndex.from_arrays : Convert list of arrays to MultiIndex.
MultiIndex.from_product : Create a MultiIndex from the cartesian product
of iterables.
MultiIndex.from_tuples : Convert list of tuples to a MultiIndex.
MultiIndex.from_frame : Make a MultiIndex from a DataFrame.
Index : The base pandas Index type.
Notes
-----
See the `user guide
<https://pandas.pydata.org/pandas-docs/stable/user_guide/advanced.html>`_
for more.
Examples
--------
A new ``MultiIndex`` is typically constructed using one of the helper
methods :meth:`MultiIndex.from_arrays`, :meth:`MultiIndex.from_product`
and :meth:`MultiIndex.from_tuples`. For example (using ``.from_arrays``):
>>> arrays = [[1, 1, 2, 2], ['red', 'blue', 'red', 'blue']]
>>> pd.MultiIndex.from_arrays(arrays, names=('number', 'color'))
MultiIndex([(1, 'red'),
(1, 'blue'),
(2, 'red'),
(2, 'blue')],
names=['number', 'color'])
See further examples for how to construct a MultiIndex in the doc strings
of the mentioned helper methods.
"""
_deprecations = Index._deprecations | frozenset()
# initialize to zero-length tuples to make everything work
_typ = "multiindex"
_names = FrozenList()
_levels = FrozenList()
_codes = FrozenList()
_comparables = ["names"]
rename = Index.set_names
_tuples = None
sortorder: Optional[int]
# --------------------------------------------------------------------
# Constructors
def __new__(
cls,
levels=None,
codes=None,
sortorder=None,
names=None,
dtype=None,
copy=False,
name=None,
verify_integrity: bool = True,
_set_identity: bool = True,
):
# compat with Index
if name is not None:
names = name
if levels is None or codes is None:
raise TypeError("Must pass both levels and codes")
if len(levels) != len(codes):
raise ValueError("Length of levels and codes must be the same.")
if len(levels) == 0:
raise ValueError("Must pass non-zero number of levels/codes")
result = object.__new__(MultiIndex)
result._cache = {}
# we've already validated levels and codes, so shortcut here
result._set_levels(levels, copy=copy, validate=False)
result._set_codes(codes, copy=copy, validate=False)
result._names = [None] * len(levels)
if names is not None:
# handles name validation
result._set_names(names)
if sortorder is not None:
result.sortorder = int(sortorder)
else:
result.sortorder = sortorder
if verify_integrity:
new_codes = result._verify_integrity()
result._codes = new_codes
if _set_identity:
result._reset_identity()
return result
def _validate_codes(self, level: List, code: List):
"""
Reassign code values as -1 if their corresponding levels are NaN.
Parameters
----------
code : list
Code to reassign.
level : list
Level to check for missing values (NaN, NaT, None).
Returns
-------
new code where code value = -1 if it corresponds
to a level with missing values (NaN, NaT, None).
"""
null_mask = isna(level)
if np.any(null_mask):
code = np.where(null_mask[code], -1, code)
return code
def _verify_integrity(
self, codes: Optional[List] = None, levels: Optional[List] = None
):
"""
Parameters
----------
codes : optional list
Codes to check for validity. Defaults to current codes.
levels : optional list
Levels to check for validity. Defaults to current levels.
Raises
------
ValueError
If length of levels and codes don't match, if the codes for any
level would exceed level bounds, or there are any duplicate levels.
Returns
-------
new codes where code value = -1 if it corresponds to a
NaN level.
"""
# NOTE: Currently does not check, among other things, that cached
# nlevels matches nor that sortorder matches actually sortorder.
codes = codes or self.codes
levels = levels or self.levels
if len(levels) != len(codes):
raise ValueError(
"Length of levels and codes must match. NOTE: "
"this index is in an inconsistent state."
)
codes_length = len(codes[0])
for i, (level, level_codes) in enumerate(zip(levels, codes)):
if len(level_codes) != codes_length:
raise ValueError(
f"Unequal code lengths: {[len(code_) for code_ in codes]}"
)
if len(level_codes) and level_codes.max() >= len(level):
raise ValueError(
f"On level {i}, code max ({level_codes.max()}) >= length of "
f"level ({len(level)}). NOTE: this index is in an "
"inconsistent state"
)
if len(level_codes) and level_codes.min() < -1:
raise ValueError(f"On level {i}, code value ({level_codes.min()}) < -1")
if not level.is_unique:
raise ValueError(
f"Level values must be unique: {list(level)} on level {i}"
)
if self.sortorder is not None:
if self.sortorder > self._lexsort_depth():
raise ValueError(
"Value for sortorder must be inferior or equal to actual "
f"lexsort_depth: sortorder {self.sortorder} "
f"with lexsort_depth {self._lexsort_depth()}"
)
codes = [
self._validate_codes(level, code) for level, code in zip(levels, codes)
]
new_codes = FrozenList(codes)
return new_codes
@classmethod
def from_arrays(cls, arrays, sortorder=None, names=lib.no_default):
"""
Convert arrays to MultiIndex.
Parameters
----------
arrays : list / sequence of array-likes
Each array-like gives one level's value for each data point.
len(arrays) is the number of levels.
sortorder : int or None
Level of sortedness (must be lexicographically sorted by that
level).
names : list / sequence of str, optional
Names for the levels in the index.
Returns
-------
MultiIndex
See Also
--------
MultiIndex.from_tuples : Convert list of tuples to MultiIndex.
MultiIndex.from_product : Make a MultiIndex from cartesian product
of iterables.
MultiIndex.from_frame : Make a MultiIndex from a DataFrame.
Examples
--------
>>> arrays = [[1, 1, 2, 2], ['red', 'blue', 'red', 'blue']]
>>> pd.MultiIndex.from_arrays(arrays, names=('number', 'color'))
MultiIndex([(1, 'red'),
(1, 'blue'),
(2, 'red'),
(2, 'blue')],
names=['number', 'color'])
"""
error_msg = "Input must be a list / sequence of array-likes."
if not is_list_like(arrays):
raise TypeError(error_msg)
elif is_iterator(arrays):
arrays = list(arrays)
# Check if elements of array are list-like
for array in arrays:
if not is_list_like(array):
raise TypeError(error_msg)
# Check if lengths of all arrays are equal or not,
# raise ValueError, if not
for i in range(1, len(arrays)):
if len(arrays[i]) != len(arrays[i - 1]):
raise ValueError("all arrays must be same length")
codes, levels = factorize_from_iterables(arrays)
if names is lib.no_default:
names = [getattr(arr, "name", None) for arr in arrays]
return MultiIndex(
levels=levels,
codes=codes,
sortorder=sortorder,
names=names,
verify_integrity=False,
)
@classmethod
def from_tuples(cls, tuples, sortorder=None, names=None):
"""
Convert list of tuples to MultiIndex.
Parameters
----------
tuples : list / sequence of tuple-likes
Each tuple is the index of one row/column.
sortorder : int or None
Level of sortedness (must be lexicographically sorted by that
level).
names : list / sequence of str, optional
Names for the levels in the index.
Returns
-------
MultiIndex
See Also
--------
MultiIndex.from_arrays : Convert list of arrays to MultiIndex.
MultiIndex.from_product : Make a MultiIndex from cartesian product
of iterables.
MultiIndex.from_frame : Make a MultiIndex from a DataFrame.
Examples
--------
>>> tuples = [(1, 'red'), (1, 'blue'),
... (2, 'red'), (2, 'blue')]
>>> pd.MultiIndex.from_tuples(tuples, names=('number', 'color'))
MultiIndex([(1, 'red'),
(1, 'blue'),
(2, 'red'),
(2, 'blue')],
names=['number', 'color'])
"""
if not is_list_like(tuples):
raise TypeError("Input must be a list / sequence of tuple-likes.")
elif is_iterator(tuples):
tuples = list(tuples)
if len(tuples) == 0:
if names is None:
raise TypeError("Cannot infer number of levels from empty list")
arrays = [[]] * len(names)
elif isinstance(tuples, (np.ndarray, Index)):
if isinstance(tuples, Index):
tuples = tuples._values
arrays = list(lib.tuples_to_object_array(tuples).T)
elif isinstance(tuples, list):
arrays = list(lib.to_object_array_tuples(tuples).T)
else:
arrays = zip(*tuples)
return MultiIndex.from_arrays(arrays, sortorder=sortorder, names=names)
@classmethod
def from_product(cls, iterables, sortorder=None, names=lib.no_default):
"""
Make a MultiIndex from the cartesian product of multiple iterables.
Parameters
----------
iterables : list / sequence of iterables
Each iterable has unique labels for each level of the index.
sortorder : int or None
Level of sortedness (must be lexicographically sorted by that
level).
names : list / sequence of str, optional
Names for the levels in the index.
.. versionchanged:: 1.0.0
If not explicitly provided, names will be inferred from the
elements of iterables if an element has a name attribute
Returns
-------
MultiIndex
See Also
--------
MultiIndex.from_arrays : Convert list of arrays to MultiIndex.
MultiIndex.from_tuples : Convert list of tuples to MultiIndex.
MultiIndex.from_frame : Make a MultiIndex from a DataFrame.
Examples
--------
>>> numbers = [0, 1, 2]
>>> colors = ['green', 'purple']
>>> pd.MultiIndex.from_product([numbers, colors],
... names=['number', 'color'])
MultiIndex([(0, 'green'),
(0, 'purple'),
(1, 'green'),
(1, 'purple'),
(2, 'green'),
(2, 'purple')],
names=['number', 'color'])
"""
from pandas.core.reshape.util import cartesian_product
if not is_list_like(iterables):
raise TypeError("Input must be a list / sequence of iterables.")
elif is_iterator(iterables):
iterables = list(iterables)
codes, levels = factorize_from_iterables(iterables)
if names is lib.no_default:
names = [getattr(it, "name", None) for it in iterables]
codes = cartesian_product(codes)
return MultiIndex(levels, codes, sortorder=sortorder, names=names)
@classmethod
def from_frame(cls, df, sortorder=None, names=None):
"""
Make a MultiIndex from a DataFrame.
.. versionadded:: 0.24.0
Parameters
----------
df : DataFrame
DataFrame to be converted to MultiIndex.
sortorder : int, optional
Level of sortedness (must be lexicographically sorted by that
level).
names : list-like, optional
If no names are provided, use the column names, or tuple of column
names if the columns is a MultiIndex. If a sequence, overwrite
names with the given sequence.
Returns
-------
MultiIndex
The MultiIndex representation of the given DataFrame.
See Also
--------
MultiIndex.from_arrays : Convert list of arrays to MultiIndex.
MultiIndex.from_tuples : Convert list of tuples to MultiIndex.
MultiIndex.from_product : Make a MultiIndex from cartesian product
of iterables.
Examples
--------
>>> df = pd.DataFrame([['HI', 'Temp'], ['HI', 'Precip'],
... ['NJ', 'Temp'], ['NJ', 'Precip']],
... columns=['a', 'b'])
>>> df
a b
0 HI Temp
1 HI Precip
2 NJ Temp
3 NJ Precip
>>> pd.MultiIndex.from_frame(df)
MultiIndex([('HI', 'Temp'),
('HI', 'Precip'),
('NJ', 'Temp'),
('NJ', 'Precip')],
names=['a', 'b'])
Using explicit names, instead of the column names
>>> pd.MultiIndex.from_frame(df, names=['state', 'observation'])
MultiIndex([('HI', 'Temp'),
('HI', 'Precip'),
('NJ', 'Temp'),
('NJ', 'Precip')],
names=['state', 'observation'])
"""
if not isinstance(df, ABCDataFrame):
raise TypeError("Input must be a DataFrame")
column_names, columns = zip(*df.items())
names = column_names if names is None else names
return cls.from_arrays(columns, sortorder=sortorder, names=names)
# --------------------------------------------------------------------
@property
def _values(self):
# We override here, since our parent uses _data, which we don't use.
return self.values
@property
def values(self):
if self._tuples is not None:
return self._tuples
values = []
for i in range(self.nlevels):
vals = self._get_level_values(i)
if is_categorical_dtype(vals):
vals = vals._internal_get_values()
if isinstance(vals.dtype, ExtensionDtype) or hasattr(vals, "_box_values"):
vals = vals.astype(object)
vals = np.array(vals, copy=False)
values.append(vals)
self._tuples = lib.fast_zip(values)
return self._tuples
@property
def array(self):
"""
Raises a ValueError for `MultiIndex` because there's no single
array backing a MultiIndex.
Raises
------
ValueError
"""
raise ValueError(
"MultiIndex has no single backing array. Use "
"'MultiIndex.to_numpy()' to get a NumPy array of tuples."
)
@property
def shape(self):
"""
Return a tuple of the shape of the underlying data.
"""
# overriding the base Index.shape definition to avoid materializing
# the values (GH-27384, GH-27775)
return (len(self),)
def __len__(self) -> int:
return len(self.codes[0])
# --------------------------------------------------------------------
# Levels Methods
@cache_readonly
def levels(self):
# Use cache_readonly to ensure that self.get_locs doesn't repeatedly
# create new IndexEngine
# https://github.com/pandas-dev/pandas/issues/31648
result = [
x._shallow_copy(name=name) for x, name in zip(self._levels, self._names)
]
for level in result:
# disallow midx.levels[0].name = "foo"
level._no_setting_name = True
return FrozenList(result)
def _set_levels(
self, levels, level=None, copy=False, validate=True, verify_integrity=False
):
# This is NOT part of the levels property because it should be
# externally not allowed to set levels. User beware if you change
# _levels directly
if validate:
if len(levels) == 0:
raise ValueError("Must set non-zero number of levels.")
if level is None and len(levels) != self.nlevels:
raise ValueError("Length of levels must match number of levels.")
if level is not None and len(levels) != len(level):
raise ValueError("Length of levels must match length of level.")
if level is None:
new_levels = FrozenList(
ensure_index(lev, copy=copy)._shallow_copy() for lev in levels
)
else:
level_numbers = [self._get_level_number(lev) for lev in level]
new_levels = list(self._levels)
for lev_num, lev in zip(level_numbers, levels):
new_levels[lev_num] = ensure_index(lev, copy=copy)._shallow_copy()
new_levels = FrozenList(new_levels)
if verify_integrity:
new_codes = self._verify_integrity(levels=new_levels)
self._codes = new_codes
names = self.names
self._levels = new_levels
if any(names):
self._set_names(names)
self._tuples = None
self._reset_cache()
def set_levels(self, levels, level=None, inplace=False, verify_integrity=True):
"""
Set new levels on MultiIndex. Defaults to returning new index.
Parameters
----------
levels : sequence or list of sequence
New level(s) to apply.
level : int, level name, or sequence of int/level names (default None)
Level(s) to set (None for all levels).
inplace : bool
If True, mutates in place.
verify_integrity : bool, default True
If True, checks that levels and codes are compatible.
Returns
-------
new index (of same type and class...etc)
Examples
--------
>>> idx = pd.MultiIndex.from_tuples([(1, 'one'), (1, 'two'),
(2, 'one'), (2, 'two'),
(3, 'one'), (3, 'two')],
names=['foo', 'bar'])
>>> idx.set_levels([['a', 'b', 'c'], [1, 2]])
MultiIndex([('a', 1),
('a', 2),
('b', 1),
('b', 2),
('c', 1),
('c', 2)],
names=['foo', 'bar'])
>>> idx.set_levels(['a', 'b', 'c'], level=0)
MultiIndex([('a', 'one'),
('a', 'two'),
('b', 'one'),
('b', 'two'),
('c', 'one'),
('c', 'two')],
names=['foo', 'bar'])
>>> idx.set_levels(['a', 'b'], level='bar')
MultiIndex([(1, 'a'),
(1, 'b'),
(2, 'a'),
(2, 'b'),
(3, 'a'),
(3, 'b')],
names=['foo', 'bar'])
If any of the levels passed to ``set_levels()`` exceeds the
existing length, all of the values from that argument will
be stored in the MultiIndex levels, though the values will
be truncated in the MultiIndex output.
>>> idx.set_levels([['a', 'b', 'c'], [1, 2, 3, 4]], level=[0, 1])
MultiIndex([('a', 1),
('a', 2),
('b', 1),
('b', 2)],
names=['foo', 'bar'])
>>> idx.set_levels([['a', 'b', 'c'], [1, 2, 3, 4]], level=[0, 1]).levels
FrozenList([['a', 'b', 'c'], [1, 2, 3, 4]])
"""
if is_list_like(levels) and not isinstance(levels, Index):
levels = list(levels)
if level is not None and not is_list_like(level):
if not is_list_like(levels):
raise TypeError("Levels must be list-like")
if is_list_like(levels[0]):
raise TypeError("Levels must be list-like")
level = [level]
levels = [levels]
elif level is None or is_list_like(level):
if not is_list_like(levels) or not is_list_like(levels[0]):
raise TypeError("Levels must be list of lists-like")
if inplace:
idx = self
else:
idx = self._shallow_copy()
idx._reset_identity()
idx._set_levels(
levels, level=level, validate=True, verify_integrity=verify_integrity
)
if not inplace:
return idx
@property
def nlevels(self) -> int:
"""
Integer number of levels in this MultiIndex.
"""
return len(self._levels)
@property
def levshape(self):
"""
A tuple with the length of each level.
"""
return tuple(len(x) for x in self.levels)
# --------------------------------------------------------------------
# Codes Methods
@property
def codes(self):
return self._codes
def _set_codes(
self, codes, level=None, copy=False, validate=True, verify_integrity=False
):
if validate:
if level is None and len(codes) != self.nlevels:
raise ValueError("Length of codes must match number of levels")
if level is not None and len(codes) != len(level):
raise ValueError("Length of codes must match length of levels.")
if level is None:
new_codes = FrozenList(
_coerce_indexer_frozen(level_codes, lev, copy=copy).view()
for lev, level_codes in zip(self._levels, codes)
)
else:
level_numbers = [self._get_level_number(lev) for lev in level]
new_codes = list(self._codes)
for lev_num, level_codes in zip(level_numbers, codes):
lev = self.levels[lev_num]
new_codes[lev_num] = _coerce_indexer_frozen(level_codes, lev, copy=copy)
new_codes = FrozenList(new_codes)
if verify_integrity:
new_codes = self._verify_integrity(codes=new_codes)
self._codes = new_codes
self._tuples = None
self._reset_cache()
def set_codes(self, codes, level=None, inplace=False, verify_integrity=True):
"""
Set new codes on MultiIndex. Defaults to returning
new index.
.. versionadded:: 0.24.0
New name for deprecated method `set_labels`.
Parameters
----------
codes : sequence or list of sequence
New codes to apply.
level : int, level name, or sequence of int/level names (default None)
Level(s) to set (None for all levels).
inplace : bool
If True, mutates in place.
verify_integrity : bool (default True)
If True, checks that levels and codes are compatible.
Returns
-------
new index (of same type and class...etc)
Examples
--------
>>> idx = pd.MultiIndex.from_tuples([(1, 'one'),
(1, 'two'),
(2, 'one'),
(2, 'two')],
names=['foo', 'bar'])
>>> idx.set_codes([[1, 0, 1, 0], [0, 0, 1, 1]])
MultiIndex([(2, 'one'),
(1, 'one'),
(2, 'two'),
(1, 'two')],
names=['foo', 'bar'])
>>> idx.set_codes([1, 0, 1, 0], level=0)
MultiIndex([(2, 'one'),
(1, 'two'),
(2, 'one'),
(1, 'two')],
names=['foo', 'bar'])
>>> idx.set_codes([0, 0, 1, 1], level='bar')
MultiIndex([(1, 'one'),
(1, 'one'),
(2, 'two'),
(2, 'two')],
names=['foo', 'bar'])
>>> idx.set_codes([[1, 0, 1, 0], [0, 0, 1, 1]], level=[0, 1])
MultiIndex([(2, 'one'),
(1, 'one'),
(2, 'two'),
(1, 'two')],
names=['foo', 'bar'])
"""
if level is not None and not is_list_like(level):
if not is_list_like(codes):
raise TypeError("Codes must be list-like")
if is_list_like(codes[0]):
raise TypeError("Codes must be list-like")
level = [level]
codes = [codes]
elif level is None or is_list_like(level):
if not is_list_like(codes) or not is_list_like(codes[0]):
raise TypeError("Codes must be list of lists-like")
if inplace:
idx = self
else:
idx = self._shallow_copy()
idx._reset_identity()
idx._set_codes(codes, level=level, verify_integrity=verify_integrity)
if not inplace:
return idx
# --------------------------------------------------------------------
# Index Internals
@cache_readonly
def _engine(self):
# Calculate the number of bits needed to represent labels in each
# level, as log2 of their sizes (including -1 for NaN):
sizes = np.ceil(np.log2([len(l) + 1 for l in self.levels]))
# Sum bit counts, starting from the _right_....
lev_bits = np.cumsum(sizes[::-1])[::-1]
# ... in order to obtain offsets such that sorting the combination of
# shifted codes (one for each level, resulting in a unique integer) is
# equivalent to sorting lexicographically the codes themselves. Notice
# that each level needs to be shifted by the number of bits needed to
# represent the _previous_ ones:
offsets = np.concatenate([lev_bits[1:], [0]]).astype("uint64")
# Check the total number of bits needed for our representation:
if lev_bits[0] > 64:
# The levels would overflow a 64 bit uint - use Python integers:
return MultiIndexPyIntEngine(self.levels, self.codes, offsets)
return MultiIndexUIntEngine(self.levels, self.codes, offsets)
@property
def _constructor(self):
return MultiIndex.from_tuples
@Appender(Index._shallow_copy.__doc__)
def _shallow_copy(self, values=None, **kwargs):
if values is not None:
names = kwargs.pop("names", kwargs.pop("name", self.names))
# discards freq
kwargs.pop("freq", None)
return MultiIndex.from_tuples(values, names=names, **kwargs)
result = self.copy(**kwargs)
result._cache = self._cache.copy()
# GH32669
if "levels" in result._cache:
del result._cache["levels"]
return result
def _shallow_copy_with_infer(self, values, **kwargs):
# On equal MultiIndexes the difference is empty.
# Therefore, an empty MultiIndex is returned GH13490
if len(values) == 0:
return MultiIndex(
levels=[[] for _ in range(self.nlevels)],
codes=[[] for _ in range(self.nlevels)],
**kwargs,
)
return self._shallow_copy(values, **kwargs)
# --------------------------------------------------------------------
def copy(
self,
names=None,
dtype=None,
levels=None,
codes=None,
deep=False,
name=None,
_set_identity=False,
):
"""
Make a copy of this object. Names, dtype, levels and codes can be
passed and will be set on new copy.
Parameters
----------
names : sequence, optional
dtype : numpy dtype or pandas type, optional
levels : sequence, optional
codes : sequence, optional
deep : bool, default False
name : Label
Kept for compatibility with 1-dimensional Index. Should not be used.
Returns
-------
MultiIndex
Notes
-----
In most cases, there should be no functional difference from using
``deep``, but if ``deep`` is passed it will attempt to deepcopy.
This could be potentially expensive on large MultiIndex objects.
"""
names = self._validate_names(name=name, names=names, deep=deep)
if deep:
from copy import deepcopy
if levels is None:
levels = deepcopy(self.levels)
if codes is None:
codes = deepcopy(self.codes)
else:
if levels is None:
levels = self.levels
if codes is None:
codes = self.codes
return MultiIndex(
levels=levels,
codes=codes,
names=names,
sortorder=self.sortorder,
verify_integrity=False,
_set_identity=_set_identity,
)
def __array__(self, dtype=None) -> np.ndarray:
""" the array interface, return my values """
return self.values
def view(self, cls=None):
""" this is defined as a copy with the same identity """
result = self.copy()
result._id = self._id
return result
@Appender(Index.__contains__.__doc__)
def __contains__(self, key: Any) -> bool:
hash(key)
try:
self.get_loc(key)
return True
except (LookupError, TypeError, ValueError):
return False
@cache_readonly
def dtype(self) -> np.dtype:
return np.dtype("O")
def _is_memory_usage_qualified(self) -> bool:
""" return a boolean if we need a qualified .info display """
def f(l):
return "mixed" in l or "string" in l or "unicode" in l
return any(f(l) for l in self._inferred_type_levels)
@Appender(Index.memory_usage.__doc__)
def memory_usage(self, deep: bool = False) -> int:
# we are overwriting our base class to avoid
# computing .values here which could materialize
# a tuple representation unnecessarily
return self._nbytes(deep)
@cache_readonly
def nbytes(self) -> int:
""" return the number of bytes in the underlying data """
return self._nbytes(False)
def _nbytes(self, deep: bool = False) -> int:
"""
return the number of bytes in the underlying data
deeply introspect the level data if deep=True
include the engine hashtable
*this is in internal routine*
"""
# for implementations with no useful getsizeof (PyPy)
objsize = 24
level_nbytes = sum(i.memory_usage(deep=deep) for i in self.levels)
label_nbytes = sum(i.nbytes for i in self.codes)
names_nbytes = sum(getsizeof(i, objsize) for i in self.names)
result = level_nbytes + label_nbytes + names_nbytes
# include our engine hashtable
result += self._engine.sizeof(deep=deep)
return result
# --------------------------------------------------------------------
# Rendering Methods
def _formatter_func(self, tup):
"""
Formats each item in tup according to its level's formatter function.
"""
formatter_funcs = [level._formatter_func for level in self.levels]
return tuple(func(val) for func, val in zip(formatter_funcs, tup))
def _format_data(self, name=None):
"""
Return the formatted data as a unicode string
"""
return format_object_summary(
self, self._formatter_func, name=name, line_break_each_value=True
)
def _format_attrs(self):
"""
Return a list of tuples of the (attr,formatted_value).
"""
return format_object_attrs(self, include_dtype=False)
def _format_native_types(self, na_rep="nan", **kwargs):
new_levels = []
new_codes = []
# go through the levels and format them
for level, level_codes in zip(self.levels, self.codes):
level = level._format_native_types(na_rep=na_rep, **kwargs)
# add nan values, if there are any
mask = level_codes == -1
if mask.any():
nan_index = len(level)
level = np.append(level, na_rep)
assert not level_codes.flags.writeable # i.e. copy is needed
level_codes = level_codes.copy() # make writeable
level_codes[mask] = nan_index
new_levels.append(level)
new_codes.append(level_codes)
if len(new_levels) == 1:
# a single-level multi-index
return Index(new_levels[0].take(new_codes[0]))._format_native_types()
else:
# reconstruct the multi-index
mi = MultiIndex(
levels=new_levels,
codes=new_codes,
names=self.names,
sortorder=self.sortorder,
verify_integrity=False,
)
return mi._values
def format(
self,
space=2,
sparsify=None,
adjoin=True,
names=False,
na_rep=None,
formatter=None,
):
if len(self) == 0:
return []
stringified_levels = []
for lev, level_codes in zip(self.levels, self.codes):
na = na_rep if na_rep is not None else _get_na_rep(lev.dtype.type)
if len(lev) > 0:
formatted = lev.take(level_codes).format(formatter=formatter)
# we have some NA
mask = level_codes == -1
if mask.any():
formatted = np.array(formatted, dtype=object)
formatted[mask] = na
formatted = formatted.tolist()
else:
# weird all NA case
formatted = [
pprint_thing(na if isna(x) else x, escape_chars=("\t", "\r", "\n"))
for x in algos.take_1d(lev._values, level_codes)
]
stringified_levels.append(formatted)
result_levels = []
for lev, name in zip(stringified_levels, self.names):
level = []
if names:
level.append(
pprint_thing(name, escape_chars=("\t", "\r", "\n"))
if name is not None
else ""
)
level.extend(np.array(lev, dtype=object))
result_levels.append(level)
if sparsify is None:
sparsify = get_option("display.multi_sparse")
if sparsify:
sentinel = ""
# GH3547
# use value of sparsify as sentinel, unless it's an obvious
# "Truthy" value
if sparsify not in [True, 1]:
sentinel = sparsify
# little bit of a kludge job for #1217
result_levels = _sparsify(
result_levels, start=int(names), sentinel=sentinel
)
if adjoin:
from pandas.io.formats.format import _get_adjustment
adj = _get_adjustment()
return adj.adjoin(space, *result_levels).split("\n")
else:
return result_levels
# --------------------------------------------------------------------
# Names Methods
def _get_names(self):
return FrozenList(self._names)
def _set_names(self, names, level=None, validate=True):
"""
Set new names on index. Each name has to be a hashable type.
Parameters
----------
values : str or sequence
name(s) to set
level : int, level name, or sequence of int/level names (default None)
If the index is a MultiIndex (hierarchical), level(s) to set (None
for all levels). Otherwise level must be None
validate : boolean, default True
validate that the names match level lengths
Raises
------
TypeError if each name is not hashable.
Notes
-----
sets names on levels. WARNING: mutates!
Note that you generally want to set this *after* changing levels, so
that it only acts on copies
"""
# GH 15110
# Don't allow a single string for names in a MultiIndex
if names is not None and not is_list_like(names):
raise ValueError("Names should be list-like for a MultiIndex")
names = list(names)
if validate:
if level is not None and len(names) != len(level):
raise ValueError("Length of names must match length of level.")
if level is None and len(names) != self.nlevels:
raise ValueError(
"Length of names must match number of levels in MultiIndex."
)
if level is None:
level = range(self.nlevels)
else:
level = [self._get_level_number(lev) for lev in level]
# set the name
for lev, name in zip(level, names):
if name is not None:
# GH 20527
# All items in 'names' need to be hashable:
if not is_hashable(name):
raise TypeError(
f"{type(self).__name__}.name must be a hashable type"
)
self._names[lev] = name
# If .levels has been accessed, the names in our cache will be stale.
self._reset_cache()
names = property(
fset=_set_names, fget=_get_names, doc="""\nNames of levels in MultiIndex.\n"""
)
# --------------------------------------------------------------------
@Appender(Index._get_grouper_for_level.__doc__)
def _get_grouper_for_level(self, mapper, level):
indexer = self.codes[level]
level_index = self.levels[level]
if mapper is not None:
# Handle group mapping function and return
level_values = self.levels[level].take(indexer)
grouper = level_values.map(mapper)
return grouper, None, None
codes, uniques = algos.factorize(indexer, sort=True)
if len(uniques) > 0 and uniques[0] == -1:
# Handle NAs
mask = indexer != -1
ok_codes, uniques = algos.factorize(indexer[mask], sort=True)
codes = np.empty(len(indexer), dtype=indexer.dtype)
codes[mask] = ok_codes
codes[~mask] = -1
if len(uniques) < len(level_index):
# Remove unobserved levels from level_index
level_index = level_index.take(uniques)
else:
# break references back to us so that setting the name
# on the output of a groupby doesn't reflect back here.
level_index = level_index.copy()
if level_index._can_hold_na:
grouper = level_index.take(codes, fill_value=True)
else:
grouper = level_index.take(codes)
return grouper, codes, level_index
@cache_readonly
def inferred_type(self) -> str:
return "mixed"
def _get_level_number(self, level) -> int:
count = self.names.count(level)
if (count > 1) and not is_integer(level):
raise ValueError(
f"The name {level} occurs multiple times, use a level number"
)
try:
level = self.names.index(level)
except ValueError as err:
if not is_integer(level):
raise KeyError(f"Level {level} not found") from err
elif level < 0:
level += self.nlevels
if level < 0:
orig_level = level - self.nlevels
raise IndexError(
f"Too many levels: Index has only {self.nlevels} levels, "
f"{orig_level} is not a valid level number"
) from err
# Note: levels are zero-based
elif level >= self.nlevels:
raise IndexError(
f"Too many levels: Index has only {self.nlevels} levels, "
f"not {level + 1}"
) from err
return level
@property
def _has_complex_internals(self) -> bool:
# used to avoid libreduction code paths, which raise or require conversion
return True
@cache_readonly
def is_monotonic_increasing(self) -> bool:
"""
return if the index is monotonic increasing (only equal or
increasing) values.
"""
if all(x.is_monotonic for x in self.levels):
# If each level is sorted, we can operate on the codes directly. GH27495
return libalgos.is_lexsorted(
[x.astype("int64", copy=False) for x in self.codes]
)
# reversed() because lexsort() wants the most significant key last.
values = [
self._get_level_values(i).values for i in reversed(range(len(self.levels)))
]
try:
sort_order = np.lexsort(values)
return Index(sort_order).is_monotonic
except TypeError:
# we have mixed types and np.lexsort is not happy
return Index(self._values).is_monotonic
@cache_readonly
def is_monotonic_decreasing(self) -> bool:
"""
return if the index is monotonic decreasing (only equal or
decreasing) values.
"""
# monotonic decreasing if and only if reverse is monotonic increasing
return self[::-1].is_monotonic_increasing
@cache_readonly
def _inferred_type_levels(self):
""" return a list of the inferred types, one for each level """
return [i.inferred_type for i in self.levels]
@Appender(Index.duplicated.__doc__)
def duplicated(self, keep="first"):
shape = map(len, self.levels)
ids = get_group_index(self.codes, shape, sort=False, xnull=False)
return duplicated_int64(ids, keep)
def fillna(self, value=None, downcast=None):
"""
fillna is not implemented for MultiIndex
"""
raise NotImplementedError("isna is not defined for MultiIndex")
@Appender(Index.dropna.__doc__)
def dropna(self, how="any"):
nans = [level_codes == -1 for level_codes in self.codes]
if how == "any":
indexer = np.any(nans, axis=0)
elif how == "all":
indexer = np.all(nans, axis=0)
else:
raise ValueError(f"invalid how option: {how}")
new_codes = [level_codes[~indexer] for level_codes in self.codes]
return self.copy(codes=new_codes, deep=True)
def _get_level_values(self, level, unique=False):
"""
Return vector of label values for requested level,
equal to the length of the index
**this is an internal method**
Parameters
----------
level : int level
unique : bool, default False
if True, drop duplicated values
Returns
-------
values : ndarray
"""
lev = self.levels[level]
level_codes = self.codes[level]
name = self._names[level]
if unique:
level_codes = algos.unique(level_codes)
filled = algos.take_1d(lev._values, level_codes, fill_value=lev._na_value)
return lev._shallow_copy(filled, name=name)
def get_level_values(self, level):
"""
Return vector of label values for requested level,
equal to the length of the index.
Parameters
----------
level : int or str
``level`` is either the integer position of the level in the
MultiIndex, or the name of the level.
Returns
-------
values : Index
Values is a level of this MultiIndex converted to
a single :class:`Index` (or subclass thereof).
Examples
--------
Create a MultiIndex:
>>> mi = pd.MultiIndex.from_arrays((list('abc'), list('def')))
>>> mi.names = ['level_1', 'level_2']
Get level values by supplying level as either integer or name:
>>> mi.get_level_values(0)
Index(['a', 'b', 'c'], dtype='object', name='level_1')
>>> mi.get_level_values('level_2')
Index(['d', 'e', 'f'], dtype='object', name='level_2')
"""
level = self._get_level_number(level)
values = self._get_level_values(level)
return values
@Appender(Index.unique.__doc__)
def unique(self, level=None):
if level is None:
return super().unique()
else:
level = self._get_level_number(level)
return self._get_level_values(level=level, unique=True)
def _to_safe_for_reshape(self):
""" convert to object if we are a categorical """
return self.set_levels([i._to_safe_for_reshape() for i in self.levels])
def to_frame(self, index=True, name=None):
"""
Create a DataFrame with the levels of the MultiIndex as columns.
Column ordering is determined by the DataFrame constructor with data as
a dict.
.. versionadded:: 0.24.0
Parameters
----------
index : bool, default True
Set the index of the returned DataFrame as the original MultiIndex.
name : list / sequence of str, optional
The passed names should substitute index level names.
Returns
-------
DataFrame : a DataFrame containing the original MultiIndex data.
See Also
--------
DataFrame
"""
from pandas import DataFrame
if name is not None:
if not is_list_like(name):
raise TypeError("'name' must be a list / sequence of column names.")
if len(name) != len(self.levels):
raise ValueError(
"'name' should have same length as number of levels on index."
)
idx_names = name
else:
idx_names = self.names
# Guarantee resulting column order - PY36+ dict maintains insertion order
result = DataFrame(
{
(level if lvlname is None else lvlname): self._get_level_values(level)
for lvlname, level in zip(idx_names, range(len(self.levels)))
},
copy=False,
)
if index:
result.index = self
return result
def to_flat_index(self):
"""
Convert a MultiIndex to an Index of Tuples containing the level values.
.. versionadded:: 0.24.0
Returns
-------
pd.Index
Index with the MultiIndex data represented in Tuples.
Notes
-----
This method will simply return the caller if called by anything other
than a MultiIndex.
Examples
--------
>>> index = pd.MultiIndex.from_product(
... [['foo', 'bar'], ['baz', 'qux']],
... names=['a', 'b'])
>>> index.to_flat_index()
Index([('foo', 'baz'), ('foo', 'qux'),
('bar', 'baz'), ('bar', 'qux')],
dtype='object')
"""
return Index(self._values, tupleize_cols=False)
@property
def is_all_dates(self) -> bool:
return False
def is_lexsorted(self) -> bool:
"""
Return True if the codes are lexicographically sorted.
Returns
-------
bool
"""
return self.lexsort_depth == self.nlevels
@cache_readonly
def lexsort_depth(self):
if self.sortorder is not None:
return self.sortorder
return self._lexsort_depth()
def _lexsort_depth(self) -> int:
"""
Compute and return the lexsort_depth, the number of levels of the
MultiIndex that are sorted lexically
Returns
-------
int
"""
int64_codes = [ensure_int64(level_codes) for level_codes in self.codes]
for k in range(self.nlevels, 0, -1):
if libalgos.is_lexsorted(int64_codes[:k]):
return k
return 0
def _sort_levels_monotonic(self):
"""
This is an *internal* function.
Create a new MultiIndex from the current to monotonically sorted
items IN the levels. This does not actually make the entire MultiIndex
monotonic, JUST the levels.
The resulting MultiIndex will have the same outward
appearance, meaning the same .values and ordering. It will also
be .equals() to the original.
Returns
-------
MultiIndex
Examples
--------
>>> mi = pd.MultiIndex(levels=[['a', 'b'], ['bb', 'aa']],
... codes=[[0, 0, 1, 1], [0, 1, 0, 1]])
>>> mi
MultiIndex([('a', 'bb'),
('a', 'aa'),
('b', 'bb'),
('b', 'aa')],
)
>>> mi.sort_values()
MultiIndex([('a', 'aa'),
('a', 'bb'),
('b', 'aa'),
('b', 'bb')],
)
"""
if self.is_lexsorted() and self.is_monotonic:
return self
new_levels = []
new_codes = []
for lev, level_codes in zip(self.levels, self.codes):
if not lev.is_monotonic:
try:
# indexer to reorder the levels
indexer = lev.argsort()
except TypeError:
pass
else:
lev = lev.take(indexer)
# indexer to reorder the level codes
indexer = ensure_int64(indexer)
ri = lib.get_reverse_indexer(indexer, len(indexer))
level_codes = algos.take_1d(ri, level_codes)
new_levels.append(lev)
new_codes.append(level_codes)
return MultiIndex(
new_levels,
new_codes,
names=self.names,
sortorder=self.sortorder,
verify_integrity=False,
)
def remove_unused_levels(self):
"""
Create a new MultiIndex from the current that removes
unused levels, meaning that they are not expressed in the labels.
The resulting MultiIndex will have the same outward
appearance, meaning the same .values and ordering. It will also
be .equals() to the original.
Returns
-------
MultiIndex
Examples
--------
>>> mi = pd.MultiIndex.from_product([range(2), list('ab')])
>>> mi
MultiIndex([(0, 'a'),
(0, 'b'),
(1, 'a'),
(1, 'b')],
)
>>> mi[2:]
MultiIndex([(1, 'a'),
(1, 'b')],
)
The 0 from the first level is not represented
and can be removed
>>> mi2 = mi[2:].remove_unused_levels()
>>> mi2.levels
FrozenList([[1], ['a', 'b']])
"""
new_levels = []
new_codes = []
changed = False
for lev, level_codes in zip(self.levels, self.codes):
# Since few levels are typically unused, bincount() is more
# efficient than unique() - however it only accepts positive values
# (and drops order):
uniques = np.where(np.bincount(level_codes + 1) > 0)[0] - 1
has_na = int(len(uniques) and (uniques[0] == -1))
if len(uniques) != len(lev) + has_na:
# We have unused levels
changed = True
# Recalculate uniques, now preserving order.
# Can easily be cythonized by exploiting the already existing
# "uniques" and stop parsing "level_codes" when all items
# are found:
uniques = algos.unique(level_codes)
if has_na:
na_idx = np.where(uniques == -1)[0]
# Just ensure that -1 is in first position:
uniques[[0, na_idx[0]]] = uniques[[na_idx[0], 0]]
# codes get mapped from uniques to 0:len(uniques)
# -1 (if present) is mapped to last position
code_mapping = np.zeros(len(lev) + has_na)
# ... and reassigned value -1:
code_mapping[uniques] = np.arange(len(uniques)) - has_na
level_codes = code_mapping[level_codes]
# new levels are simple
lev = lev.take(uniques[has_na:])
new_levels.append(lev)
new_codes.append(level_codes)
result = self.view()
if changed:
result._reset_identity()
result._set_levels(new_levels, validate=False)
result._set_codes(new_codes, validate=False)
return result
# --------------------------------------------------------------------
# Pickling Methods
def __reduce__(self):
"""Necessary for making this object picklable"""
d = dict(
levels=list(self.levels),
codes=list(self.codes),
sortorder=self.sortorder,
names=list(self.names),
)
return ibase._new_Index, (type(self), d), None
# --------------------------------------------------------------------
def __getitem__(self, key):
if is_scalar(key):
key = com.cast_scalar_indexer(key)
retval = []
for lev, level_codes in zip(self.levels, self.codes):
if level_codes[key] == -1:
retval.append(np.nan)
else:
retval.append(lev[level_codes[key]])
return tuple(retval)
else:
if com.is_bool_indexer(key):
key = np.asarray(key, dtype=bool)
sortorder = self.sortorder
else:
# cannot be sure whether the result will be sorted
sortorder = None
if isinstance(key, Index):
key = np.asarray(key)
new_codes = [level_codes[key] for level_codes in self.codes]
return MultiIndex(
levels=self.levels,
codes=new_codes,
names=self.names,
sortorder=sortorder,
verify_integrity=False,
)
@Appender(_index_shared_docs["take"] % _index_doc_kwargs)
def take(self, indices, axis=0, allow_fill=True, fill_value=None, **kwargs):
nv.validate_take(tuple(), kwargs)
indices = ensure_platform_int(indices)
taken = self._assert_take_fillable(
self.codes,
indices,
allow_fill=allow_fill,
fill_value=fill_value,
na_value=-1,
)
return MultiIndex(
levels=self.levels, codes=taken, names=self.names, verify_integrity=False
)
def _assert_take_fillable(
self, values, indices, allow_fill=True, fill_value=None, na_value=None
):
""" Internal method to handle NA filling of take """
# only fill if we are passing a non-None fill_value
if allow_fill and fill_value is not None:
if (indices < -1).any():
msg = (
"When allow_fill=True and fill_value is not None, "
"all indices must be >= -1"
)
raise ValueError(msg)
taken = [lab.take(indices) for lab in self.codes]
mask = indices == -1
if mask.any():
masked = []
for new_label in taken:
label_values = new_label
label_values[mask] = na_value
masked.append(np.asarray(label_values))
taken = masked
else:
taken = [lab.take(indices) for lab in self.codes]
return taken
def append(self, other):
"""
Append a collection of Index options together
Parameters
----------
other : Index or list/tuple of indices
Returns
-------
appended : Index
"""
if not isinstance(other, (list, tuple)):
other = [other]
if all(
(isinstance(o, MultiIndex) and o.nlevels >= self.nlevels) for o in other
):
arrays = []
for i in range(self.nlevels):
label = self._get_level_values(i)
appended = [o._get_level_values(i) for o in other]
arrays.append(label.append(appended))
return MultiIndex.from_arrays(arrays, names=self.names)
to_concat = (self._values,) + tuple(k._values for k in other)
new_tuples = np.concatenate(to_concat)
# if all(isinstance(x, MultiIndex) for x in other):
try:
return MultiIndex.from_tuples(new_tuples, names=self.names)
except (TypeError, IndexError):
return Index(new_tuples)
def argsort(self, *args, **kwargs) -> np.ndarray:
return self._values.argsort(*args, **kwargs)
@Appender(_index_shared_docs["repeat"] % _index_doc_kwargs)
def repeat(self, repeats, axis=None):
nv.validate_repeat(tuple(), dict(axis=axis))
repeats = ensure_platform_int(repeats)
return MultiIndex(
levels=self.levels,
codes=[
level_codes.view(np.ndarray).astype(np.intp).repeat(repeats)
for level_codes in self.codes
],
names=self.names,
sortorder=self.sortorder,
verify_integrity=False,
)
def where(self, cond, other=None):
raise NotImplementedError(".where is not supported for MultiIndex operations")
def drop(self, codes, level=None, errors="raise"):
"""
Make new MultiIndex with passed list of codes deleted
Parameters
----------
codes : array-like
Must be a list of tuples
level : int or level name, default None
errors : str, default 'raise'
Returns
-------
dropped : MultiIndex
"""
if level is not None:
return self._drop_from_level(codes, level, errors)
if not isinstance(codes, (np.ndarray, Index)):
try:
codes = com.index_labels_to_array(codes, dtype=object)
except ValueError:
pass
inds = []
for level_codes in codes:
try:
loc = self.get_loc(level_codes)
# get_loc returns either an integer, a slice, or a boolean
# mask
if isinstance(loc, int):
inds.append(loc)
elif isinstance(loc, slice):
inds.extend(range(loc.start, loc.stop))
elif com.is_bool_indexer(loc):
if self.lexsort_depth == 0:
warnings.warn(
"dropping on a non-lexsorted multi-index "
"without a level parameter may impact performance.",
PerformanceWarning,
stacklevel=3,
)
loc = loc.nonzero()[0]
inds.extend(loc)
else:
msg = f"unsupported indexer of type {type(loc)}"
raise AssertionError(msg)
except KeyError:
if errors != "ignore":
raise
return self.delete(inds)
def _drop_from_level(self, codes, level, errors="raise"):
codes = com.index_labels_to_array(codes)
i = self._get_level_number(level)
index = self.levels[i]
values = index.get_indexer(codes)
mask = ~algos.isin(self.codes[i], values)
if mask.all() and errors != "ignore":
raise KeyError(f"labels {codes} not found in level")
return self[mask]
def swaplevel(self, i=-2, j=-1):
"""
Swap level i with level j.
Calling this method does not change the ordering of the values.
Parameters
----------
i : int, str, default -2
First level of index to be swapped. Can pass level name as string.
Type of parameters can be mixed.
j : int, str, default -1
Second level of index to be swapped. Can pass level name as string.
Type of parameters can be mixed.
Returns
-------
MultiIndex
A new MultiIndex.
See Also
--------
Series.swaplevel : Swap levels i and j in a MultiIndex.
Dataframe.swaplevel : Swap levels i and j in a MultiIndex on a
particular axis.
Examples
--------
>>> mi = pd.MultiIndex(levels=[['a', 'b'], ['bb', 'aa']],
... codes=[[0, 0, 1, 1], [0, 1, 0, 1]])
>>> mi
MultiIndex([('a', 'bb'),
('a', 'aa'),
('b', 'bb'),
('b', 'aa')],
)
>>> mi.swaplevel(0, 1)
MultiIndex([('bb', 'a'),
('aa', 'a'),
('bb', 'b'),
('aa', 'b')],
)
"""
new_levels = list(self.levels)
new_codes = list(self.codes)
new_names = list(self.names)
i = self._get_level_number(i)
j = self._get_level_number(j)
new_levels[i], new_levels[j] = new_levels[j], new_levels[i]
new_codes[i], new_codes[j] = new_codes[j], new_codes[i]
new_names[i], new_names[j] = new_names[j], new_names[i]
return MultiIndex(
levels=new_levels, codes=new_codes, names=new_names, verify_integrity=False
)
def reorder_levels(self, order):
"""
Rearrange levels using input order. May not drop or duplicate levels.
Parameters
----------
order : list of int or list of str
List representing new level order. Reference level by number
(position) or by key (label).
Returns
-------
MultiIndex
"""
order = [self._get_level_number(i) for i in order]
if len(order) != self.nlevels:
raise AssertionError(
f"Length of order must be same as number of levels ({self.nlevels}), "
f"got {len(order)}"
)
new_levels = [self.levels[i] for i in order]
new_codes = [self.codes[i] for i in order]
new_names = [self.names[i] for i in order]
return MultiIndex(
levels=new_levels, codes=new_codes, names=new_names, verify_integrity=False
)
def _get_codes_for_sorting(self):
"""
we categorizing our codes by using the
available categories (all, not just observed)
excluding any missing ones (-1); this is in preparation
for sorting, where we need to disambiguate that -1 is not
a valid valid
"""
def cats(level_codes):
return np.arange(
np.array(level_codes).max() + 1 if len(level_codes) else 0,
dtype=level_codes.dtype,
)
return [
Categorical.from_codes(level_codes, cats(level_codes), ordered=True)
for level_codes in self.codes
]
def sortlevel(self, level=0, ascending=True, sort_remaining=True):
"""
Sort MultiIndex at the requested level. The result will respect the
original ordering of the associated factor at that level.
Parameters
----------
level : list-like, int or str, default 0
If a string is given, must be a name of the level.
If list-like must be names or ints of levels.
ascending : bool, default True
False to sort in descending order.
Can also be a list to specify a directed ordering.
sort_remaining : sort by the remaining levels after level
Returns
-------
sorted_index : pd.MultiIndex
Resulting index.
indexer : np.ndarray
Indices of output values in original index.
"""
if isinstance(level, (str, int)):
level = [level]
level = [self._get_level_number(lev) for lev in level]
sortorder = None
# we have a directed ordering via ascending
if isinstance(ascending, list):
if not len(level) == len(ascending):
raise ValueError("level must have same length as ascending")
indexer = lexsort_indexer(
[self.codes[lev] for lev in level], orders=ascending
)
# level ordering
else:
codes = list(self.codes)
shape = list(self.levshape)
# partition codes and shape
primary = tuple(codes[lev] for lev in level)
primshp = tuple(shape[lev] for lev in level)
# Reverse sorted to retain the order of
# smaller indices that needs to be removed
for lev in sorted(level, reverse=True):
codes.pop(lev)
shape.pop(lev)
if sort_remaining:
primary += primary + tuple(codes)
primshp += primshp + tuple(shape)
else:
sortorder = level[0]
indexer = indexer_from_factorized(primary, primshp, compress=False)
if not ascending:
indexer = indexer[::-1]
indexer = ensure_platform_int(indexer)
new_codes = [level_codes.take(indexer) for level_codes in self.codes]
new_index = MultiIndex(
codes=new_codes,
levels=self.levels,
names=self.names,
sortorder=sortorder,
verify_integrity=False,
)
return new_index, indexer
def reindex(self, target, method=None, level=None, limit=None, tolerance=None):
"""
Create index with target's values (move/add/delete values as necessary)
Returns
-------
new_index : pd.MultiIndex
Resulting index
indexer : np.ndarray or None
Indices of output values in original index.
"""
# GH6552: preserve names when reindexing to non-named target
# (i.e. neither Index nor Series).
preserve_names = not hasattr(target, "names")
if level is not None:
if method is not None:
raise TypeError("Fill method not supported if level passed")
# GH7774: preserve dtype/tz if target is empty and not an Index.
# target may be an iterator
target = ibase._ensure_has_len(target)
if len(target) == 0 and not isinstance(target, Index):
idx = self.levels[level]
attrs = idx._get_attributes_dict()
attrs.pop("freq", None) # don't preserve freq
target = type(idx)._simple_new(np.empty(0, dtype=idx.dtype), **attrs)
else:
target = ensure_index(target)
target, indexer, _ = self._join_level(
target, level, how="right", return_indexers=True, keep_order=False
)
else:
target = ensure_index(target)
if self.equals(target):
indexer = None
else:
if self.is_unique:
indexer = self.get_indexer(
target, method=method, limit=limit, tolerance=tolerance
)
else:
raise ValueError("cannot handle a non-unique multi-index!")
if not isinstance(target, MultiIndex):
if indexer is None:
target = self
elif (indexer >= 0).all():
target = self.take(indexer)
else:
# hopefully?
target = MultiIndex.from_tuples(target)
if (
preserve_names
and target.nlevels == self.nlevels
and target.names != self.names
):
target = target.copy(deep=False)
target.names = self.names
return target, indexer
# --------------------------------------------------------------------
# Indexing Methods
def get_value(self, series, key):
# Label-based
if not is_hashable(key) or is_iterator(key):
# We allow tuples if they are hashable, whereas other Index
# subclasses require scalar.
# We have to explicitly exclude generators, as these are hashable.
raise InvalidIndexError(key)
try:
loc = self.get_loc(key)
except KeyError:
if is_integer(key):
loc = key
else:
raise
return self._get_values_for_loc(series, loc, key)
def _get_values_for_loc(self, series: "Series", loc, key):
"""
Do a positional lookup on the given Series, returning either a scalar
or a Series.
Assumes that `series.index is self`
"""
new_values = series._values[loc]
if is_scalar(loc):
return new_values
new_index = self[loc]
new_index = maybe_droplevels(new_index, key)
new_ser = series._constructor(new_values, index=new_index, name=series.name)
return new_ser.__finalize__(series)
def _convert_listlike_indexer(self, keyarr):
"""
Parameters
----------
keyarr : list-like
Indexer to convert.
Returns
-------
tuple (indexer, keyarr)
indexer is an ndarray or None if cannot convert
keyarr are tuple-safe keys
"""
indexer, keyarr = super()._convert_listlike_indexer(keyarr)
# are we indexing a specific level
if indexer is None and len(keyarr) and not isinstance(keyarr[0], tuple):
level = 0
_, indexer = self.reindex(keyarr, level=level)
# take all
if indexer is None:
indexer = np.arange(len(self))
check = self.levels[0].get_indexer(keyarr)
mask = check == -1
if mask.any():
raise KeyError(f"{keyarr[mask]} not in index")
return indexer, keyarr
def _get_partial_string_timestamp_match_key(self, key):
"""
Translate any partial string timestamp matches in key, returning the
new key.
Only relevant for MultiIndex.
"""
# GH#10331
if isinstance(key, str) and self.levels[0]._supports_partial_string_indexing:
# Convert key '2016-01-01' to
# ('2016-01-01'[, slice(None, None, None)]+)
key = tuple([key] + [slice(None)] * (len(self.levels) - 1))
if isinstance(key, tuple):
# Convert (..., '2016-01-01', ...) in tuple to
# (..., slice('2016-01-01', '2016-01-01', None), ...)
new_key = []
for i, component in enumerate(key):
if (
isinstance(component, str)
and self.levels[i]._supports_partial_string_indexing
):
new_key.append(slice(component, component, None))
else:
new_key.append(component)
key = tuple(new_key)
return key
@Appender(_index_shared_docs["get_indexer"] % _index_doc_kwargs)
def get_indexer(self, target, method=None, limit=None, tolerance=None):
method = missing.clean_reindex_fill_method(method)
target = ensure_index(target)
# empty indexer
if is_list_like(target) and not len(target):
return ensure_platform_int(np.array([]))
if not isinstance(target, MultiIndex):
try:
target = MultiIndex.from_tuples(target)
except (TypeError, ValueError):
# let's instead try with a straight Index
if method is None:
return Index(self._values).get_indexer(
target, method=method, limit=limit, tolerance=tolerance
)
if not self.is_unique:
raise ValueError("Reindexing only valid with uniquely valued Index objects")
if method == "pad" or method == "backfill":
if tolerance is not None:
raise NotImplementedError(
"tolerance not implemented yet for MultiIndex"
)
indexer = self._engine.get_indexer(target, method, limit)
elif method == "nearest":
raise NotImplementedError(
"method='nearest' not implemented yet "
"for MultiIndex; see GitHub issue 9365"
)
else:
indexer = self._engine.get_indexer(target)
return ensure_platform_int(indexer)
@Appender(_index_shared_docs["get_indexer_non_unique"] % _index_doc_kwargs)
def get_indexer_non_unique(self, target):
return super().get_indexer_non_unique(target)
def get_slice_bound(
self, label: Union[Hashable, Sequence[Hashable]], side: str, kind: str
) -> int:
"""
For an ordered MultiIndex, compute slice bound
that corresponds to given label.
Returns leftmost (one-past-the-rightmost if `side=='right') position
of given label.
Parameters
----------
label : object or tuple of objects
side : {'left', 'right'}
kind : {'loc', 'getitem'}
Returns
-------
int
Index of label.
Notes
-----
This method only works if level 0 index of the MultiIndex is lexsorted.
Examples
--------
>>> mi = pd.MultiIndex.from_arrays([list('abbc'), list('gefd')])
Get the locations from the leftmost 'b' in the first level
until the end of the multiindex:
>>> mi.get_slice_bound('b', side="left", kind="loc")
1
Like above, but if you get the locations from the rightmost
'b' in the first level and 'f' in the second level:
>>> mi.get_slice_bound(('b','f'), side="right", kind="loc")
3
See Also
--------
MultiIndex.get_loc : Get location for a label or a tuple of labels.
MultiIndex.get_locs : Get location for a label/slice/list/mask or a
sequence of such.
"""
if not isinstance(label, tuple):
label = (label,)
return self._partial_tup_index(label, side=side)
def slice_locs(self, start=None, end=None, step=None, kind=None):
"""
For an ordered MultiIndex, compute the slice locations for input
labels.
The input labels can be tuples representing partial levels, e.g. for a
MultiIndex with 3 levels, you can pass a single value (corresponding to
the first level), or a 1-, 2-, or 3-tuple.
Parameters
----------
start : label or tuple, default None
If None, defaults to the beginning
end : label or tuple
If None, defaults to the end
step : int or None
Slice step
kind : string, optional, defaults None
Returns
-------
(start, end) : (int, int)
Notes
-----
This method only works if the MultiIndex is properly lexsorted. So,
if only the first 2 levels of a 3-level MultiIndex are lexsorted,
you can only pass two levels to ``.slice_locs``.
Examples
--------
>>> mi = pd.MultiIndex.from_arrays([list('abbd'), list('deff')],
... names=['A', 'B'])
Get the slice locations from the beginning of 'b' in the first level
until the end of the multiindex:
>>> mi.slice_locs(start='b')
(1, 4)
Like above, but stop at the end of 'b' in the first level and 'f' in
the second level:
>>> mi.slice_locs(start='b', end=('b', 'f'))
(1, 3)
See Also
--------
MultiIndex.get_loc : Get location for a label or a tuple of labels.
MultiIndex.get_locs : Get location for a label/slice/list/mask or a
sequence of such.
"""
# This function adds nothing to its parent implementation (the magic
# happens in get_slice_bound method), but it adds meaningful doc.
return super().slice_locs(start, end, step, kind=kind)
def _partial_tup_index(self, tup, side="left"):
if len(tup) > self.lexsort_depth:
raise UnsortedIndexError(
f"Key length ({len(tup)}) was greater than MultiIndex lexsort depth "
f"({self.lexsort_depth})"
)
n = len(tup)
start, end = 0, len(self)
zipped = zip(tup, self.levels, self.codes)
for k, (lab, lev, labs) in enumerate(zipped):
section = labs[start:end]
if lab not in lev and not isna(lab):
if not lev.is_type_compatible(lib.infer_dtype([lab], skipna=False)):
raise TypeError(f"Level type mismatch: {lab}")
# short circuit
loc = lev.searchsorted(lab, side=side)
if side == "right" and loc >= 0:
loc -= 1
return start + section.searchsorted(loc, side=side)
idx = self._get_loc_single_level_index(lev, lab)
if k < n - 1:
end = start + section.searchsorted(idx, side="right")
start = start + section.searchsorted(idx, side="left")
else:
return start + section.searchsorted(idx, side=side)
def _get_loc_single_level_index(self, level_index: Index, key: Hashable) -> int:
"""
If key is NA value, location of index unify as -1.
Parameters
----------
level_index: Index
key : label
Returns
-------
loc : int
If key is NA value, loc is -1
Else, location of key in index.
See Also
--------
Index.get_loc : The get_loc method for (single-level) index.
"""
if is_scalar(key) and isna(key):
return -1
else:
return level_index.get_loc(key)
def get_loc(self, key, method=None):
"""
Get location for a label or a tuple of labels as an integer, slice or
boolean mask.
Parameters
----------
key : label or tuple of labels (one for each level)
method : None
Returns
-------
loc : int, slice object or boolean mask
If the key is past the lexsort depth, the return may be a
boolean mask array, otherwise it is always a slice or int.
See Also
--------
Index.get_loc : The get_loc method for (single-level) index.
MultiIndex.slice_locs : Get slice location given start label(s) and
end label(s).
MultiIndex.get_locs : Get location for a label/slice/list/mask or a
sequence of such.
Notes
-----
The key cannot be a slice, list of same-level labels, a boolean mask,
or a sequence of such. If you want to use those, use
:meth:`MultiIndex.get_locs` instead.
Examples
--------
>>> mi = pd.MultiIndex.from_arrays([list('abb'), list('def')])
>>> mi.get_loc('b')
slice(1, 3, None)
>>> mi.get_loc(('b', 'e'))
1
"""
if method is not None:
raise NotImplementedError(
"only the default get_loc method is "
"currently supported for MultiIndex"
)
def _maybe_to_slice(loc):
"""convert integer indexer to boolean mask or slice if possible"""
if not isinstance(loc, np.ndarray) or loc.dtype != "int64":
return loc
loc = lib.maybe_indices_to_slice(loc, len(self))
if isinstance(loc, slice):
return loc
mask = np.empty(len(self), dtype="bool")
mask.fill(False)
mask[loc] = True
return mask
if not isinstance(key, (tuple, list)):
# not including list here breaks some indexing, xref #30892
loc = self._get_level_indexer(key, level=0)
return _maybe_to_slice(loc)
keylen = len(key)
if self.nlevels < keylen:
raise KeyError(
f"Key length ({keylen}) exceeds index depth ({self.nlevels})"
)
if keylen == self.nlevels and self.is_unique:
return self._engine.get_loc(key)
# -- partial selection or non-unique index
# break the key into 2 parts based on the lexsort_depth of the index;
# the first part returns a continuous slice of the index; the 2nd part
# needs linear search within the slice
i = self.lexsort_depth
lead_key, follow_key = key[:i], key[i:]
start, stop = (
self.slice_locs(lead_key, lead_key) if lead_key else (0, len(self))
)
if start == stop:
raise KeyError(key)
if not follow_key:
return slice(start, stop)
warnings.warn(
"indexing past lexsort depth may impact performance.",
PerformanceWarning,
stacklevel=10,
)
loc = np.arange(start, stop, dtype="int64")
for i, k in enumerate(follow_key, len(lead_key)):
mask = self.codes[i][loc] == self._get_loc_single_level_index(
self.levels[i], k
)
if not mask.all():
loc = loc[mask]
if not len(loc):
raise KeyError(key)
return _maybe_to_slice(loc) if len(loc) != stop - start else slice(start, stop)
def get_loc_level(self, key, level=0, drop_level: bool = True):
"""
Get both the location for the requested label(s) and the
resulting sliced index.
Parameters
----------
key : label or sequence of labels
level : int/level name or list thereof, optional
drop_level : bool, default True
If ``False``, the resulting index will not drop any level.
Returns
-------
loc : A 2-tuple where the elements are:
Element 0: int, slice object or boolean array
Element 1: The resulting sliced multiindex/index. If the key
contains all levels, this will be ``None``.
See Also
--------
MultiIndex.get_loc : Get location for a label or a tuple of labels.
MultiIndex.get_locs : Get location for a label/slice/list/mask or a
sequence of such.
Examples
--------
>>> mi = pd.MultiIndex.from_arrays([list('abb'), list('def')],
... names=['A', 'B'])
>>> mi.get_loc_level('b')
(slice(1, 3, None), Index(['e', 'f'], dtype='object', name='B'))
>>> mi.get_loc_level('e', level='B')
(array([False, True, False], dtype=bool),
Index(['b'], dtype='object', name='A'))
>>> mi.get_loc_level(['b', 'e'])
(1, None)
"""
# different name to distinguish from maybe_droplevels
def maybe_mi_droplevels(indexer, levels, drop_level: bool):
if not drop_level:
return self[indexer]
# kludgearound
orig_index = new_index = self[indexer]
levels = [self._get_level_number(i) for i in levels]
for i in sorted(levels, reverse=True):
try:
new_index = new_index.droplevel(i)
except ValueError:
# no dropping here
return orig_index
return new_index
if isinstance(level, (tuple, list)):
if len(key) != len(level):
raise AssertionError(
"Key for location must have same length as number of levels"
)
result = None
for lev, k in zip(level, key):
loc, new_index = self.get_loc_level(k, level=lev)
if isinstance(loc, slice):
mask = np.zeros(len(self), dtype=bool)
mask[loc] = True
loc = mask
result = loc if result is None else result & loc
return result, maybe_mi_droplevels(result, level, drop_level)
level = self._get_level_number(level)
# kludge for #1796
if isinstance(key, list):
key = tuple(key)
if isinstance(key, tuple) and level == 0:
try:
if key in self.levels[0]:
indexer = self._get_level_indexer(key, level=level)
new_index = maybe_mi_droplevels(indexer, [0], drop_level)
return indexer, new_index
except (TypeError, InvalidIndexError):
pass
if not any(isinstance(k, slice) for k in key):
# partial selection
# optionally get indexer to avoid re-calculation
def partial_selection(key, indexer=None):
if indexer is None:
indexer = self.get_loc(key)
ilevels = [
i for i in range(len(key)) if key[i] != slice(None, None)
]
return indexer, maybe_mi_droplevels(indexer, ilevels, drop_level)
if len(key) == self.nlevels and self.is_unique:
# Complete key in unique index -> standard get_loc
try:
return (self._engine.get_loc(key), None)
except KeyError as e:
raise KeyError(key) from e
else:
return partial_selection(key)
else:
indexer = None
for i, k in enumerate(key):
if not isinstance(k, slice):
k = self._get_level_indexer(k, level=i)
if isinstance(k, slice):
# everything
if k.start == 0 and k.stop == len(self):
k = slice(None, None)
else:
k_index = k
if isinstance(k, slice):
if k == slice(None, None):
continue
else:
raise TypeError(key)
if indexer is None:
indexer = k_index
else: # pragma: no cover
indexer &= k_index
if indexer is None:
indexer = slice(None, None)
ilevels = [i for i in range(len(key)) if key[i] != slice(None, None)]
return indexer, maybe_mi_droplevels(indexer, ilevels, drop_level)
else:
indexer = self._get_level_indexer(key, level=level)
return indexer, maybe_mi_droplevels(indexer, [level], drop_level)
def _get_level_indexer(self, key, level=0, indexer=None):
# return an indexer, boolean array or a slice showing where the key is
# in the totality of values
# if the indexer is provided, then use this
level_index = self.levels[level]
level_codes = self.codes[level]
def convert_indexer(start, stop, step, indexer=indexer, codes=level_codes):
# given the inputs and the codes/indexer, compute an indexer set
# if we have a provided indexer, then this need not consider
# the entire labels set
r = np.arange(start, stop, step)
if indexer is not None and len(indexer) != len(codes):
# we have an indexer which maps the locations in the labels
# that we have already selected (and is not an indexer for the
# entire set) otherwise this is wasteful so we only need to
# examine locations that are in this set the only magic here is
# that the result are the mappings to the set that we have
# selected
from pandas import Series
mapper = Series(indexer)
indexer = codes.take(ensure_platform_int(indexer))
result = Series(Index(indexer).isin(r).nonzero()[0])
m = result.map(mapper)
m = np.asarray(m)
else:
m = np.zeros(len(codes), dtype=bool)
m[np.in1d(codes, r, assume_unique=Index(codes).is_unique)] = True
return m
if isinstance(key, slice):
# handle a slice, returning a slice if we can
# otherwise a boolean indexer
try:
if key.start is not None:
start = level_index.get_loc(key.start)
else:
start = 0
if key.stop is not None:
stop = level_index.get_loc(key.stop)
else:
stop = len(level_index) - 1
step = key.step
except KeyError:
# we have a partial slice (like looking up a partial date
# string)
start = stop = level_index.slice_indexer(
key.start, key.stop, key.step, kind="loc"
)
step = start.step
if isinstance(start, slice) or isinstance(stop, slice):
# we have a slice for start and/or stop
# a partial date slicer on a DatetimeIndex generates a slice
# note that the stop ALREADY includes the stopped point (if
# it was a string sliced)
start = getattr(start, "start", start)
stop = getattr(stop, "stop", stop)
return convert_indexer(start, stop, step)
elif level > 0 or self.lexsort_depth == 0 or step is not None:
# need to have like semantics here to right
# searching as when we are using a slice
# so include the stop+1 (so we include stop)
return convert_indexer(start, stop + 1, step)
else:
# sorted, so can return slice object -> view
i = level_codes.searchsorted(start, side="left")
j = level_codes.searchsorted(stop, side="right")
return slice(i, j, step)
else:
code = self._get_loc_single_level_index(level_index, key)
if level > 0 or self.lexsort_depth == 0:
# Desired level is not sorted
locs = np.array(level_codes == code, dtype=bool, copy=False)
if not locs.any():
# The label is present in self.levels[level] but unused:
raise KeyError(key)
return locs
i = level_codes.searchsorted(code, side="left")
j = level_codes.searchsorted(code, side="right")
if i == j:
# The label is present in self.levels[level] but unused:
raise KeyError(key)
return slice(i, j)
def get_locs(self, seq):
"""
Get location for a sequence of labels.
Parameters
----------
seq : label, slice, list, mask or a sequence of such
You should use one of the above for each level.
If a level should not be used, set it to ``slice(None)``.
Returns
-------
numpy.ndarray
NumPy array of integers suitable for passing to iloc.
See Also
--------
MultiIndex.get_loc : Get location for a label or a tuple of labels.
MultiIndex.slice_locs : Get slice location given start label(s) and
end label(s).
Examples
--------
>>> mi = pd.MultiIndex.from_arrays([list('abb'), list('def')])
>>> mi.get_locs('b') # doctest: +SKIP
array([1, 2], dtype=int64)
>>> mi.get_locs([slice(None), ['e', 'f']]) # doctest: +SKIP
array([1, 2], dtype=int64)
>>> mi.get_locs([[True, False, True], slice('e', 'f')]) # doctest: +SKIP
array([2], dtype=int64)
"""
from pandas.core.indexes.numeric import Int64Index
# must be lexsorted to at least as many levels
true_slices = [i for (i, s) in enumerate(com.is_true_slices(seq)) if s]
if true_slices and true_slices[-1] >= self.lexsort_depth:
raise UnsortedIndexError(
"MultiIndex slicing requires the index to be lexsorted: slicing "
f"on levels {true_slices}, lexsort depth {self.lexsort_depth}"
)
# indexer
# this is the list of all values that we want to select
n = len(self)
indexer = None
def _convert_to_indexer(r) -> Int64Index:
# return an indexer
if isinstance(r, slice):
m = np.zeros(n, dtype=bool)
m[r] = True
r = m.nonzero()[0]
elif com.is_bool_indexer(r):
if len(r) != n:
raise ValueError(
"cannot index with a boolean indexer "
"that is not the same length as the "
"index"
)
r = r.nonzero()[0]
return Int64Index(r)
def _update_indexer(idxr, indexer=indexer):
if indexer is None:
indexer = Index(np.arange(n))
if idxr is None:
return indexer
return indexer & idxr
for i, k in enumerate(seq):
if com.is_bool_indexer(k):
# a boolean indexer, must be the same length!
k = np.asarray(k)
indexer = _update_indexer(_convert_to_indexer(k), indexer=indexer)
elif is_list_like(k):
# a collection of labels to include from this level (these
# are or'd)
indexers = None
for x in k:
try:
idxrs = _convert_to_indexer(
self._get_level_indexer(x, level=i, indexer=indexer)
)
indexers = idxrs if indexers is None else indexers | idxrs
except KeyError:
# ignore not founds
continue
if indexers is not None:
indexer = _update_indexer(indexers, indexer=indexer)
else:
# no matches we are done
return np.array([], dtype=np.int64)
elif com.is_null_slice(k):
# empty slice
indexer = _update_indexer(None, indexer=indexer)
elif isinstance(k, slice):
# a slice, include BOTH of the labels
indexer = _update_indexer(
_convert_to_indexer(
self._get_level_indexer(k, level=i, indexer=indexer)
),
indexer=indexer,
)
else:
# a single label
indexer = _update_indexer(
_convert_to_indexer(
self.get_loc_level(k, level=i, drop_level=False)[0]
),
indexer=indexer,
)
# empty indexer
if indexer is None:
return np.array([], dtype=np.int64)
assert isinstance(indexer, Int64Index), type(indexer)
indexer = self._reorder_indexer(seq, indexer)
return indexer._values
def _reorder_indexer(
self,
seq: Tuple[Union[Scalar, Iterable, AnyArrayLike], ...],
indexer: Int64Index,
) -> Int64Index:
"""
Reorder an indexer of a MultiIndex (self) so that the label are in the
same order as given in seq
Parameters
----------
seq : label/slice/list/mask or a sequence of such
indexer: an Int64Index indexer of self
Returns
-------
indexer : a sorted Int64Index indexer of self ordered as seq
"""
# If the index is lexsorted and the list_like label in seq are sorted
# then we do not need to sort
if self.is_lexsorted():
need_sort = False
for i, k in enumerate(seq):
if is_list_like(k):
if not need_sort:
k_codes = self.levels[i].get_indexer(k)
k_codes = k_codes[k_codes >= 0] # Filter absent keys
# True if the given codes are not ordered
need_sort = (k_codes[:-1] > k_codes[1:]).any()
# Bail out if both index and seq are sorted
if not need_sort:
return indexer
n = len(self)
keys: Tuple[np.ndarray, ...] = tuple()
# For each level of the sequence in seq, map the level codes with the
# order they appears in a list-like sequence
# This mapping is then use to reorder the indexer
for i, k in enumerate(seq):
if com.is_bool_indexer(k):
new_order = np.arange(n)[indexer]
elif is_list_like(k):
# Generate a map with all level codes as sorted initially
key_order_map = np.ones(len(self.levels[i]), dtype=np.uint64) * len(
self.levels[i]
)
# Set order as given in the indexer list
level_indexer = self.levels[i].get_indexer(k)
level_indexer = level_indexer[level_indexer >= 0] # Filter absent keys
key_order_map[level_indexer] = np.arange(len(level_indexer))
new_order = key_order_map[self.codes[i][indexer]]
else:
# For all other case, use the same order as the level
new_order = np.arange(n)[indexer]
keys = (new_order,) + keys
# Find the reordering using lexsort on the keys mapping
ind = np.lexsort(keys)
return indexer[ind]
def truncate(self, before=None, after=None):
"""
Slice index between two labels / tuples, return new MultiIndex
Parameters
----------
before : label or tuple, can be partial. Default None
None defaults to start
after : label or tuple, can be partial. Default None
None defaults to end
Returns
-------
truncated : MultiIndex
"""
if after and before and after < before:
raise ValueError("after < before")
i, j = self.levels[0].slice_locs(before, after)
left, right = self.slice_locs(before, after)
new_levels = list(self.levels)
new_levels[0] = new_levels[0][i:j]
new_codes = [level_codes[left:right] for level_codes in self.codes]
new_codes[0] = new_codes[0] - i
return MultiIndex(levels=new_levels, codes=new_codes, verify_integrity=False)
def equals(self, other) -> bool:
"""
Determines if two MultiIndex objects have the same labeling information
(the levels themselves do not necessarily have to be the same)
See Also
--------
equal_levels
"""
if self.is_(other):
return True
if not isinstance(other, Index):
return False
if not isinstance(other, MultiIndex):
# d-level MultiIndex can equal d-tuple Index
if not is_object_dtype(other.dtype):
# other cannot contain tuples, so cannot match self
return False
return array_equivalent(self._values, other._values)
if self.nlevels != other.nlevels:
return False
if len(self) != len(other):
return False
for i in range(self.nlevels):
self_codes = self.codes[i]
self_codes = self_codes[self_codes != -1]
self_values = algos.take_nd(
np.asarray(self.levels[i]._values), self_codes, allow_fill=False
)
other_codes = other.codes[i]
other_codes = other_codes[other_codes != -1]
other_values = algos.take_nd(
np.asarray(other.levels[i]._values), other_codes, allow_fill=False
)
# since we use NaT both datetime64 and timedelta64
# we can have a situation where a level is typed say
# timedelta64 in self (IOW it has other values than NaT)
# but types datetime64 in other (where its all NaT)
# but these are equivalent
if len(self_values) == 0 and len(other_values) == 0:
continue
if not array_equivalent(self_values, other_values):
return False
return True
def equal_levels(self, other) -> bool:
"""
Return True if the levels of both MultiIndex objects are the same
"""
if self.nlevels != other.nlevels:
return False
for i in range(self.nlevels):
if not self.levels[i].equals(other.levels[i]):
return False
return True
# --------------------------------------------------------------------
# Set Methods
def union(self, other, sort=None):
"""
Form the union of two MultiIndex objects
Parameters
----------
other : MultiIndex or array / Index of tuples
sort : False or None, default None
Whether to sort the resulting Index.
* None : Sort the result, except when
1. `self` and `other` are equal.
2. `self` has length 0.
3. Some values in `self` or `other` cannot be compared.
A RuntimeWarning is issued in this case.
* False : do not sort the result.
.. versionadded:: 0.24.0
.. versionchanged:: 0.24.1
Changed the default value from ``True`` to ``None``
(without change in behaviour).
Returns
-------
Index
>>> index.union(index2)
"""
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
other, result_names = self._convert_can_do_setop(other)
if len(other) == 0 or self.equals(other):
return self
# TODO: Index.union returns other when `len(self)` is 0.
uniq_tuples = lib.fast_unique_multiple(
[self._values, other._ndarray_values], sort=sort
)
return MultiIndex.from_arrays(
zip(*uniq_tuples), sortorder=0, names=result_names
)
def intersection(self, other, sort=False):
"""
Form the intersection of two MultiIndex objects.
Parameters
----------
other : MultiIndex or array / Index of tuples
sort : False or None, default False
Sort the resulting MultiIndex if possible
.. versionadded:: 0.24.0
.. versionchanged:: 0.24.1
Changed the default from ``True`` to ``False``, to match
behaviour from before 0.24.0
Returns
-------
Index
"""
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
other, result_names = self._convert_can_do_setop(other)
if self.equals(other):
return self
lvals = self._values
rvals = other._ndarray_values
uniq_tuples = None # flag whether _inner_indexer was succesful
if self.is_monotonic and other.is_monotonic:
try:
uniq_tuples = self._inner_indexer(lvals, rvals)[0]
sort = False # uniq_tuples is already sorted
except TypeError:
pass
if uniq_tuples is None:
other_uniq = set(rvals)
seen = set()
uniq_tuples = [
x for x in lvals if x in other_uniq and not (x in seen or seen.add(x))
]
if sort is None:
uniq_tuples = sorted(uniq_tuples)
if len(uniq_tuples) == 0:
return MultiIndex(
levels=self.levels,
codes=[[]] * self.nlevels,
names=result_names,
verify_integrity=False,
)
else:
return MultiIndex.from_arrays(
zip(*uniq_tuples), sortorder=0, names=result_names
)
def difference(self, other, sort=None):
"""
Compute set difference of two MultiIndex objects
Parameters
----------
other : MultiIndex
sort : False or None, default None
Sort the resulting MultiIndex if possible
.. versionadded:: 0.24.0
.. versionchanged:: 0.24.1
Changed the default value from ``True`` to ``None``
(without change in behaviour).
Returns
-------
diff : MultiIndex
"""
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
other, result_names = self._convert_can_do_setop(other)
if len(other) == 0:
return self
if self.equals(other):
return MultiIndex(
levels=self.levels,
codes=[[]] * self.nlevels,
names=result_names,
verify_integrity=False,
)
this = self._get_unique_index()
indexer = this.get_indexer(other)
indexer = indexer.take((indexer != -1).nonzero()[0])
label_diff = np.setdiff1d(np.arange(this.size), indexer, assume_unique=True)
difference = this._values.take(label_diff)
if sort is None:
difference = sorted(difference)
if len(difference) == 0:
return MultiIndex(
levels=[[]] * self.nlevels,
codes=[[]] * self.nlevels,
names=result_names,
verify_integrity=False,
)
else:
return MultiIndex.from_tuples(difference, sortorder=0, names=result_names)
def _convert_can_do_setop(self, other):
result_names = self.names
if not isinstance(other, Index):
if len(other) == 0:
other = MultiIndex(
levels=[[]] * self.nlevels,
codes=[[]] * self.nlevels,
verify_integrity=False,
)
else:
msg = "other must be a MultiIndex or a list of tuples"
try:
other = MultiIndex.from_tuples(other)
except TypeError as err:
raise TypeError(msg) from err
else:
result_names = self.names if self.names == other.names else None
return other, result_names
# --------------------------------------------------------------------
@Appender(Index.astype.__doc__)
def astype(self, dtype, copy=True):
dtype = pandas_dtype(dtype)
if is_categorical_dtype(dtype):
msg = "> 1 ndim Categorical are not supported at this time"
raise NotImplementedError(msg)
elif not is_object_dtype(dtype):
raise TypeError(
f"Setting {type(self)} dtype to anything other "
"than object is not supported"
)
elif copy is True:
return self._shallow_copy()
return self
def insert(self, loc: int, item):
"""
Make new MultiIndex inserting new item at location
Parameters
----------
loc : int
item : tuple
Must be same length as number of levels in the MultiIndex
Returns
-------
new_index : Index
"""
# Pad the key with empty strings if lower levels of the key
# aren't specified:
if not isinstance(item, tuple):
item = (item,) + ("",) * (self.nlevels - 1)
elif len(item) != self.nlevels:
raise ValueError("Item must have length equal to number of levels.")
new_levels = []
new_codes = []
for k, level, level_codes in zip(item, self.levels, self.codes):
if k not in level:
# have to insert into level
# must insert at end otherwise you have to recompute all the
# other codes
lev_loc = len(level)
level = level.insert(lev_loc, k)
else:
lev_loc = level.get_loc(k)
new_levels.append(level)
new_codes.append(np.insert(ensure_int64(level_codes), loc, lev_loc))
return MultiIndex(
levels=new_levels, codes=new_codes, names=self.names, verify_integrity=False
)
def delete(self, loc):
"""
Make new index with passed location deleted
Returns
-------
new_index : MultiIndex
"""
new_codes = [np.delete(level_codes, loc) for level_codes in self.codes]
return MultiIndex(
levels=self.levels,
codes=new_codes,
names=self.names,
verify_integrity=False,
)
def _wrap_joined_index(self, joined, other):
names = self.names if self.names == other.names else None
return MultiIndex.from_tuples(joined, names=names)
@Appender(Index.isin.__doc__)
def isin(self, values, level=None):
if level is None:
values = MultiIndex.from_tuples(values, names=self.names)._values
return algos.isin(self._values, values)
else:
num = self._get_level_number(level)
levs = self.get_level_values(num)
if levs.size == 0:
return np.zeros(len(levs), dtype=np.bool_)
return levs.isin(values)
MultiIndex._add_numeric_methods_disabled()
MultiIndex._add_numeric_methods_add_sub_disabled()
MultiIndex._add_logical_methods_disabled()
def _sparsify(label_list, start: int = 0, sentinel=""):
pivoted = list(zip(*label_list))
k = len(label_list)
result = pivoted[: start + 1]
prev = pivoted[start]
for cur in pivoted[start + 1 :]:
sparse_cur = []
for i, (p, t) in enumerate(zip(prev, cur)):
if i == k - 1:
sparse_cur.append(t)
result.append(sparse_cur)
break
if p == t:
sparse_cur.append(sentinel)
else:
sparse_cur.extend(cur[i:])
result.append(sparse_cur)
break
prev = cur
return list(zip(*result))
def _get_na_rep(dtype) -> str:
return {np.datetime64: "NaT", np.timedelta64: "NaT"}.get(dtype, "NaN")
def maybe_droplevels(index, key):
"""
Attempt to drop level or levels from the given index.
Parameters
----------
index: Index
key : scalar or tuple
Returns
-------
Index
"""
# drop levels
original_index = index
if isinstance(key, tuple):
for _ in key:
try:
index = index.droplevel(0)
except ValueError:
# we have dropped too much, so back out
return original_index
else:
try:
index = index.droplevel(0)
except ValueError:
pass
return index
def _coerce_indexer_frozen(array_like, categories, copy: bool = False) -> np.ndarray:
"""
Coerce the array_like indexer to the smallest integer dtype that can encode all
of the given categories.
Parameters
----------
array_like : array-like
categories : array-like
copy : bool
Returns
-------
np.ndarray
Non-writeable.
"""
array_like = coerce_indexer_dtype(array_like, categories)
if copy:
array_like = array_like.copy()
array_like.flags.writeable = False
return array_like
from sys import getsizeof
from typing import (
TYPE_CHECKING,
Any,
Hashable,
Iterable,
List,
Optional,
Sequence,
Tuple,
Union,
)
import warnings
import numpy as np
from pandas._config import get_option
from pandas._libs import algos as libalgos, index as libindex, lib
from pandas._libs.hashtable import duplicated_int64
from pandas._typing import AnyArrayLike, Scalar
from pandas.compat.numpy import function as nv
from pandas.errors import PerformanceWarning, UnsortedIndexError
from pandas.util._decorators import Appender, cache_readonly
from pandas.core.dtypes.cast import coerce_indexer_dtype
from pandas.core.dtypes.common import (
ensure_int64,
ensure_platform_int,
is_categorical_dtype,
is_hashable,
is_integer,
is_iterator,
is_list_like,
is_object_dtype,
is_scalar,
pandas_dtype,
)
from pandas.core.dtypes.dtypes import ExtensionDtype
from pandas.core.dtypes.generic import ABCDataFrame
from pandas.core.dtypes.missing import array_equivalent, isna
import pandas.core.algorithms as algos
from pandas.core.arrays import Categorical
from pandas.core.arrays.categorical import factorize_from_iterables
import pandas.core.common as com
import pandas.core.indexes.base as ibase
from pandas.core.indexes.base import (
Index,
InvalidIndexError,
_index_shared_docs,
ensure_index,
)
from pandas.core.indexes.frozen import FrozenList
from pandas.core.indexes.numeric import Int64Index
import pandas.core.missing as missing
from pandas.core.sorting import (
get_group_index,
indexer_from_factorized,
lexsort_indexer,
)
from pandas.io.formats.printing import (
format_object_attrs,
format_object_summary,
pprint_thing,
)
if TYPE_CHECKING:
from pandas import Series # noqa:F401
_index_doc_kwargs = dict(ibase._index_doc_kwargs)
_index_doc_kwargs.update(
dict(klass="MultiIndex", target_klass="MultiIndex or list of tuples")
)
class MultiIndexUIntEngine(libindex.BaseMultiIndexCodesEngine, libindex.UInt64Engine):
"""
This class manages a MultiIndex by mapping label combinations to positive
integers.
"""
_base = libindex.UInt64Engine
def _codes_to_ints(self, codes):
"""
Transform combination(s) of uint64 in one uint64 (each), in a strictly
monotonic way (i.e. respecting the lexicographic order of integer
combinations): see BaseMultiIndexCodesEngine documentation.
Parameters
----------
codes : 1- or 2-dimensional array of dtype uint64
Combinations of integers (one per row)
Returns
-------
scalar or 1-dimensional array, of dtype uint64
Integer(s) representing one combination (each).
"""
# Shift the representation of each level by the pre-calculated number
# of bits:
codes <<= self.offsets
# Now sum and OR are in fact interchangeable. This is a simple
# composition of the (disjunct) significant bits of each level (i.e.
# each column in "codes") in a single positive integer:
if codes.ndim == 1:
# Single key
return np.bitwise_or.reduce(codes)
# Multiple keys
return np.bitwise_or.reduce(codes, axis=1)
class MultiIndexPyIntEngine(libindex.BaseMultiIndexCodesEngine, libindex.ObjectEngine):
"""
This class manages those (extreme) cases in which the number of possible
label combinations overflows the 64 bits integers, and uses an ObjectEngine
containing Python integers.
"""
_base = libindex.ObjectEngine
def _codes_to_ints(self, codes):
"""
Transform combination(s) of uint64 in one Python integer (each), in a
strictly monotonic way (i.e. respecting the lexicographic order of
integer combinations): see BaseMultiIndexCodesEngine documentation.
Parameters
----------
codes : 1- or 2-dimensional array of dtype uint64
Combinations of integers (one per row)
Returns
-------
int, or 1-dimensional array of dtype object
Integer(s) representing one combination (each).
"""
# Shift the representation of each level by the pre-calculated number
# of bits. Since this can overflow uint64, first make sure we are
# working with Python integers:
codes = codes.astype("object") << self.offsets
# Now sum and OR are in fact interchangeable. This is a simple
# composition of the (disjunct) significant bits of each level (i.e.
# each column in "codes") in a single positive integer (per row):
if codes.ndim == 1:
# Single key
return np.bitwise_or.reduce(codes)
# Multiple keys
return np.bitwise_or.reduce(codes, axis=1)
class MultiIndex(Index):
"""
A multi-level, or hierarchical, index object for pandas objects.
Parameters
----------
levels : sequence of arrays
The unique labels for each level.
codes : sequence of arrays
Integers for each level designating which label at each location.
.. versionadded:: 0.24.0
sortorder : optional int
Level of sortedness (must be lexicographically sorted by that
level).
names : optional sequence of objects
Names for each of the index levels. (name is accepted for compat).
copy : bool, default False
Copy the meta-data.
verify_integrity : bool, default True
Check that the levels/codes are consistent and valid.
Attributes
----------
names
levels
codes
nlevels
levshape
Methods
-------
from_arrays
from_tuples
from_product
from_frame
set_levels
set_codes
to_frame
to_flat_index
is_lexsorted
sortlevel
droplevel
swaplevel
reorder_levels
remove_unused_levels
get_locs
See Also
--------
MultiIndex.from_arrays : Convert list of arrays to MultiIndex.
MultiIndex.from_product : Create a MultiIndex from the cartesian product
of iterables.
MultiIndex.from_tuples : Convert list of tuples to a MultiIndex.
MultiIndex.from_frame : Make a MultiIndex from a DataFrame.
Index : The base pandas Index type.
Notes
-----
See the `user guide
<https://pandas.pydata.org/pandas-docs/stable/user_guide/advanced.html>`_
for more.
Examples
--------
A new ``MultiIndex`` is typically constructed using one of the helper
methods :meth:`MultiIndex.from_arrays`, :meth:`MultiIndex.from_product`
and :meth:`MultiIndex.from_tuples`. For example (using ``.from_arrays``):
>>> arrays = [[1, 1, 2, 2], ['red', 'blue', 'red', 'blue']]
>>> pd.MultiIndex.from_arrays(arrays, names=('number', 'color'))
MultiIndex([(1, 'red'),
(1, 'blue'),
(2, 'red'),
(2, 'blue')],
names=['number', 'color'])
See further examples for how to construct a MultiIndex in the doc strings
of the mentioned helper methods.
"""
_deprecations = Index._deprecations | frozenset()
# initialize to zero-length tuples to make everything work
_typ = "multiindex"
_names = FrozenList()
_levels = FrozenList()
_codes = FrozenList()
_comparables = ["names"]
rename = Index.set_names
_tuples = None
sortorder: Optional[int]
# --------------------------------------------------------------------
# Constructors
def __new__(
cls,
levels=None,
codes=None,
sortorder=None,
names=None,
dtype=None,
copy=False,
name=None,
verify_integrity: bool = True,
_set_identity: bool = True,
):
# compat with Index
if name is not None:
names = name
if levels is None or codes is None:
raise TypeError("Must pass both levels and codes")
if len(levels) != len(codes):
raise ValueError("Length of levels and codes must be the same.")
if len(levels) == 0:
raise ValueError("Must pass non-zero number of levels/codes")
result = object.__new__(MultiIndex)
result._cache = {}
# we've already validated levels and codes, so shortcut here
result._set_levels(levels, copy=copy, validate=False)
result._set_codes(codes, copy=copy, validate=False)
result._names = [None] * len(levels)
if names is not None:
# handles name validation
result._set_names(names)
if sortorder is not None:
result.sortorder = int(sortorder)
else:
result.sortorder = sortorder
if verify_integrity:
new_codes = result._verify_integrity()
result._codes = new_codes
if _set_identity:
result._reset_identity()
return result
def _validate_codes(self, level: List, code: List):
"""
Reassign code values as -1 if their corresponding levels are NaN.
Parameters
----------
code : list
Code to reassign.
level : list
Level to check for missing values (NaN, NaT, None).
Returns
-------
new code where code value = -1 if it corresponds
to a level with missing values (NaN, NaT, None).
"""
null_mask = isna(level)
if np.any(null_mask):
code = np.where(null_mask[code], -1, code)
return code
def _verify_integrity(
self, codes: Optional[List] = None, levels: Optional[List] = None
):
"""
Parameters
----------
codes : optional list
Codes to check for validity. Defaults to current codes.
levels : optional list
Levels to check for validity. Defaults to current levels.
Raises
------
ValueError
If length of levels and codes don't match, if the codes for any
level would exceed level bounds, or there are any duplicate levels.
Returns
-------
new codes where code value = -1 if it corresponds to a
NaN level.
"""
# NOTE: Currently does not check, among other things, that cached
# nlevels matches nor that sortorder matches actually sortorder.
codes = codes or self.codes
levels = levels or self.levels
if len(levels) != len(codes):
raise ValueError(
"Length of levels and codes must match. NOTE: "
"this index is in an inconsistent state."
)
codes_length = len(codes[0])
for i, (level, level_codes) in enumerate(zip(levels, codes)):
if len(level_codes) != codes_length:
raise ValueError(
f"Unequal code lengths: {[len(code_) for code_ in codes]}"
)
if len(level_codes) and level_codes.max() >= len(level):
raise ValueError(
f"On level {i}, code max ({level_codes.max()}) >= length of "
f"level ({len(level)}). NOTE: this index is in an "
"inconsistent state"
)
if len(level_codes) and level_codes.min() < -1:
raise ValueError(f"On level {i}, code value ({level_codes.min()}) < -1")
if not level.is_unique:
raise ValueError(
f"Level values must be unique: {list(level)} on level {i}"
)
if self.sortorder is not None:
if self.sortorder > self._lexsort_depth():
raise ValueError(
"Value for sortorder must be inferior or equal to actual "
f"lexsort_depth: sortorder {self.sortorder} "
f"with lexsort_depth {self._lexsort_depth()}"
)
codes = [
self._validate_codes(level, code) for level, code in zip(levels, codes)
]
new_codes = FrozenList(codes)
return new_codes
@classmethod
def from_arrays(cls, arrays, sortorder=None, names=lib.no_default):
"""
Convert arrays to MultiIndex.
Parameters
----------
arrays : list / sequence of array-likes
Each array-like gives one level's value for each data point.
len(arrays) is the number of levels.
sortorder : int or None
Level of sortedness (must be lexicographically sorted by that
level).
names : list / sequence of str, optional
Names for the levels in the index.
Returns
-------
MultiIndex
See Also
--------
MultiIndex.from_tuples : Convert list of tuples to MultiIndex.
MultiIndex.from_product : Make a MultiIndex from cartesian product
of iterables.
MultiIndex.from_frame : Make a MultiIndex from a DataFrame.
Examples
--------
>>> arrays = [[1, 1, 2, 2], ['red', 'blue', 'red', 'blue']]
>>> pd.MultiIndex.from_arrays(arrays, names=('number', 'color'))
MultiIndex([(1, 'red'),
(1, 'blue'),
(2, 'red'),
(2, 'blue')],
names=['number', 'color'])
"""
error_msg = "Input must be a list / sequence of array-likes."
if not is_list_like(arrays):
raise TypeError(error_msg)
elif is_iterator(arrays):
arrays = list(arrays)
# Check if elements of array are list-like
for array in arrays:
if not is_list_like(array):
raise TypeError(error_msg)
# Check if lengths of all arrays are equal or not,
# raise ValueError, if not
for i in range(1, len(arrays)):
if len(arrays[i]) != len(arrays[i - 1]):
raise ValueError("all arrays must be same length")
codes, levels = factorize_from_iterables(arrays)
if names is lib.no_default:
names = [getattr(arr, "name", None) for arr in arrays]
return MultiIndex(
levels=levels,
codes=codes,
sortorder=sortorder,
names=names,
verify_integrity=False,
)
@classmethod
def from_tuples(cls, tuples, sortorder=None, names=None):
"""
Convert list of tuples to MultiIndex.
Parameters
----------
tuples : list / sequence of tuple-likes
Each tuple is the index of one row/column.
sortorder : int or None
Level of sortedness (must be lexicographically sorted by that
level).
names : list / sequence of str, optional
Names for the levels in the index.
Returns
-------
MultiIndex
See Also
--------
MultiIndex.from_arrays : Convert list of arrays to MultiIndex.
MultiIndex.from_product : Make a MultiIndex from cartesian product
of iterables.
MultiIndex.from_frame : Make a MultiIndex from a DataFrame.
Examples
--------
>>> tuples = [(1, 'red'), (1, 'blue'),
... (2, 'red'), (2, 'blue')]
>>> pd.MultiIndex.from_tuples(tuples, names=('number', 'color'))
MultiIndex([(1, 'red'),
(1, 'blue'),
(2, 'red'),
(2, 'blue')],
names=['number', 'color'])
"""
if not is_list_like(tuples):
raise TypeError("Input must be a list / sequence of tuple-likes.")
elif is_iterator(tuples):
tuples = list(tuples)
if len(tuples) == 0:
if names is None:
raise TypeError("Cannot infer number of levels from empty list")
arrays = [[]] * len(names)
elif isinstance(tuples, (np.ndarray, Index)):
if isinstance(tuples, Index):
tuples = tuples._values
arrays = list(lib.tuples_to_object_array(tuples).T)
elif isinstance(tuples, list):
arrays = list(lib.to_object_array_tuples(tuples).T)
else:
arrays = zip(*tuples)
return MultiIndex.from_arrays(arrays, sortorder=sortorder, names=names)
@classmethod
def from_product(cls, iterables, sortorder=None, names=lib.no_default):
"""
Make a MultiIndex from the cartesian product of multiple iterables.
Parameters
----------
iterables : list / sequence of iterables
Each iterable has unique labels for each level of the index.
sortorder : int or None
Level of sortedness (must be lexicographically sorted by that
level).
names : list / sequence of str, optional
Names for the levels in the index.
.. versionchanged:: 1.0.0
If not explicitly provided, names will be inferred from the
elements of iterables if an element has a name attribute
Returns
-------
MultiIndex
See Also
--------
MultiIndex.from_arrays : Convert list of arrays to MultiIndex.
MultiIndex.from_tuples : Convert list of tuples to MultiIndex.
MultiIndex.from_frame : Make a MultiIndex from a DataFrame.
Examples
--------
>>> numbers = [0, 1, 2]
>>> colors = ['green', 'purple']
>>> pd.MultiIndex.from_product([numbers, colors],
... names=['number', 'color'])
MultiIndex([(0, 'green'),
(0, 'purple'),
(1, 'green'),
(1, 'purple'),
(2, 'green'),
(2, 'purple')],
names=['number', 'color'])
"""
from pandas.core.reshape.util import cartesian_product
if not is_list_like(iterables):
raise TypeError("Input must be a list / sequence of iterables.")
elif is_iterator(iterables):
iterables = list(iterables)
codes, levels = factorize_from_iterables(iterables)
if names is lib.no_default:
names = [getattr(it, "name", None) for it in iterables]
# codes are all ndarrays, so cartesian_product is lossless
codes = cartesian_product(codes)
return MultiIndex(levels, codes, sortorder=sortorder, names=names)
@classmethod
def from_frame(cls, df, sortorder=None, names=None):
"""
Make a MultiIndex from a DataFrame.
.. versionadded:: 0.24.0
Parameters
----------
df : DataFrame
DataFrame to be converted to MultiIndex.
sortorder : int, optional
Level of sortedness (must be lexicographically sorted by that
level).
names : list-like, optional
If no names are provided, use the column names, or tuple of column
names if the columns is a MultiIndex. If a sequence, overwrite
names with the given sequence.
Returns
-------
MultiIndex
The MultiIndex representation of the given DataFrame.
See Also
--------
MultiIndex.from_arrays : Convert list of arrays to MultiIndex.
MultiIndex.from_tuples : Convert list of tuples to MultiIndex.
MultiIndex.from_product : Make a MultiIndex from cartesian product
of iterables.
Examples
--------
>>> df = pd.DataFrame([['HI', 'Temp'], ['HI', 'Precip'],
... ['NJ', 'Temp'], ['NJ', 'Precip']],
... columns=['a', 'b'])
>>> df
a b
0 HI Temp
1 HI Precip
2 NJ Temp
3 NJ Precip
>>> pd.MultiIndex.from_frame(df)
MultiIndex([('HI', 'Temp'),
('HI', 'Precip'),
('NJ', 'Temp'),
('NJ', 'Precip')],
names=['a', 'b'])
Using explicit names, instead of the column names
>>> pd.MultiIndex.from_frame(df, names=['state', 'observation'])
MultiIndex([('HI', 'Temp'),
('HI', 'Precip'),
('NJ', 'Temp'),
('NJ', 'Precip')],
names=['state', 'observation'])
"""
if not isinstance(df, ABCDataFrame):
raise TypeError("Input must be a DataFrame")
column_names, columns = zip(*df.items())
names = column_names if names is None else names
return cls.from_arrays(columns, sortorder=sortorder, names=names)
# --------------------------------------------------------------------
@property
def _values(self):
# We override here, since our parent uses _data, which we don't use.
return self.values
@property
def values(self):
if self._tuples is not None:
return self._tuples
values = []
for i in range(self.nlevels):
vals = self._get_level_values(i)
if is_categorical_dtype(vals):
vals = vals._internal_get_values()
if isinstance(vals.dtype, ExtensionDtype) or hasattr(vals, "_box_values"):
vals = vals.astype(object)
vals = np.array(vals, copy=False)
values.append(vals)
self._tuples = lib.fast_zip(values)
return self._tuples
@property
def array(self):
"""
Raises a ValueError for `MultiIndex` because there's no single
array backing a MultiIndex.
Raises
------
ValueError
"""
raise ValueError(
"MultiIndex has no single backing array. Use "
"'MultiIndex.to_numpy()' to get a NumPy array of tuples."
)
@property
def shape(self):
"""
Return a tuple of the shape of the underlying data.
"""
# overriding the base Index.shape definition to avoid materializing
# the values (GH-27384, GH-27775)
return (len(self),)
def __len__(self) -> int:
return len(self.codes[0])
# --------------------------------------------------------------------
# Levels Methods
@cache_readonly
def levels(self):
# Use cache_readonly to ensure that self.get_locs doesn't repeatedly
# create new IndexEngine
# https://github.com/pandas-dev/pandas/issues/31648
result = [
x._shallow_copy(name=name) for x, name in zip(self._levels, self._names)
]
for level in result:
# disallow midx.levels[0].name = "foo"
level._no_setting_name = True
return FrozenList(result)
def _set_levels(
self, levels, level=None, copy=False, validate=True, verify_integrity=False
):
# This is NOT part of the levels property because it should be
# externally not allowed to set levels. User beware if you change
# _levels directly
if validate:
if len(levels) == 0:
raise ValueError("Must set non-zero number of levels.")
if level is None and len(levels) != self.nlevels:
raise ValueError("Length of levels must match number of levels.")
if level is not None and len(levels) != len(level):
raise ValueError("Length of levels must match length of level.")
if level is None:
new_levels = FrozenList(
ensure_index(lev, copy=copy)._shallow_copy() for lev in levels
)
else:
level_numbers = [self._get_level_number(lev) for lev in level]
new_levels = list(self._levels)
for lev_num, lev in zip(level_numbers, levels):
new_levels[lev_num] = ensure_index(lev, copy=copy)._shallow_copy()
new_levels = FrozenList(new_levels)
if verify_integrity:
new_codes = self._verify_integrity(levels=new_levels)
self._codes = new_codes
names = self.names
self._levels = new_levels
if any(names):
self._set_names(names)
self._tuples = None
self._reset_cache()
def set_levels(self, levels, level=None, inplace=False, verify_integrity=True):
"""
Set new levels on MultiIndex. Defaults to returning new index.
Parameters
----------
levels : sequence or list of sequence
New level(s) to apply.
level : int, level name, or sequence of int/level names (default None)
Level(s) to set (None for all levels).
inplace : bool
If True, mutates in place.
verify_integrity : bool, default True
If True, checks that levels and codes are compatible.
Returns
-------
new index (of same type and class...etc)
Examples
--------
>>> idx = pd.MultiIndex.from_tuples([(1, 'one'), (1, 'two'),
(2, 'one'), (2, 'two'),
(3, 'one'), (3, 'two')],
names=['foo', 'bar'])
>>> idx.set_levels([['a', 'b', 'c'], [1, 2]])
MultiIndex([('a', 1),
('a', 2),
('b', 1),
('b', 2),
('c', 1),
('c', 2)],
names=['foo', 'bar'])
>>> idx.set_levels(['a', 'b', 'c'], level=0)
MultiIndex([('a', 'one'),
('a', 'two'),
('b', 'one'),
('b', 'two'),
('c', 'one'),
('c', 'two')],
names=['foo', 'bar'])
>>> idx.set_levels(['a', 'b'], level='bar')
MultiIndex([(1, 'a'),
(1, 'b'),
(2, 'a'),
(2, 'b'),
(3, 'a'),
(3, 'b')],
names=['foo', 'bar'])
If any of the levels passed to ``set_levels()`` exceeds the
existing length, all of the values from that argument will
be stored in the MultiIndex levels, though the values will
be truncated in the MultiIndex output.
>>> idx.set_levels([['a', 'b', 'c'], [1, 2, 3, 4]], level=[0, 1])
MultiIndex([('a', 1),
('a', 2),
('b', 1),
('b', 2)],
names=['foo', 'bar'])
>>> idx.set_levels([['a', 'b', 'c'], [1, 2, 3, 4]], level=[0, 1]).levels
FrozenList([['a', 'b', 'c'], [1, 2, 3, 4]])
"""
if is_list_like(levels) and not isinstance(levels, Index):
levels = list(levels)
if level is not None and not is_list_like(level):
if not is_list_like(levels):
raise TypeError("Levels must be list-like")
if is_list_like(levels[0]):
raise TypeError("Levels must be list-like")
level = [level]
levels = [levels]
elif level is None or is_list_like(level):
if not is_list_like(levels) or not is_list_like(levels[0]):
raise TypeError("Levels must be list of lists-like")
if inplace:
idx = self
else:
idx = self._shallow_copy()
idx._reset_identity()
idx._set_levels(
levels, level=level, validate=True, verify_integrity=verify_integrity
)
if not inplace:
return idx
@property
def nlevels(self) -> int:
"""
Integer number of levels in this MultiIndex.
"""
return len(self._levels)
@property
def levshape(self):
"""
A tuple with the length of each level.
"""
return tuple(len(x) for x in self.levels)
# --------------------------------------------------------------------
# Codes Methods
@property
def codes(self):
return self._codes
def _set_codes(
self, codes, level=None, copy=False, validate=True, verify_integrity=False
):
if validate:
if level is None and len(codes) != self.nlevels:
raise ValueError("Length of codes must match number of levels")
if level is not None and len(codes) != len(level):
raise ValueError("Length of codes must match length of levels.")
if level is None:
new_codes = FrozenList(
_coerce_indexer_frozen(level_codes, lev, copy=copy).view()
for lev, level_codes in zip(self._levels, codes)
)
else:
level_numbers = [self._get_level_number(lev) for lev in level]
new_codes = list(self._codes)
for lev_num, level_codes in zip(level_numbers, codes):
lev = self.levels[lev_num]
new_codes[lev_num] = _coerce_indexer_frozen(level_codes, lev, copy=copy)
new_codes = FrozenList(new_codes)
if verify_integrity:
new_codes = self._verify_integrity(codes=new_codes)
self._codes = new_codes
self._tuples = None
self._reset_cache()
def set_codes(self, codes, level=None, inplace=False, verify_integrity=True):
"""
Set new codes on MultiIndex. Defaults to returning
new index.
.. versionadded:: 0.24.0
New name for deprecated method `set_labels`.
Parameters
----------
codes : sequence or list of sequence
New codes to apply.
level : int, level name, or sequence of int/level names (default None)
Level(s) to set (None for all levels).
inplace : bool
If True, mutates in place.
verify_integrity : bool (default True)
If True, checks that levels and codes are compatible.
Returns
-------
new index (of same type and class...etc)
Examples
--------
>>> idx = pd.MultiIndex.from_tuples([(1, 'one'),
(1, 'two'),
(2, 'one'),
(2, 'two')],
names=['foo', 'bar'])
>>> idx.set_codes([[1, 0, 1, 0], [0, 0, 1, 1]])
MultiIndex([(2, 'one'),
(1, 'one'),
(2, 'two'),
(1, 'two')],
names=['foo', 'bar'])
>>> idx.set_codes([1, 0, 1, 0], level=0)
MultiIndex([(2, 'one'),
(1, 'two'),
(2, 'one'),
(1, 'two')],
names=['foo', 'bar'])
>>> idx.set_codes([0, 0, 1, 1], level='bar')
MultiIndex([(1, 'one'),
(1, 'one'),
(2, 'two'),
(2, 'two')],
names=['foo', 'bar'])
>>> idx.set_codes([[1, 0, 1, 0], [0, 0, 1, 1]], level=[0, 1])
MultiIndex([(2, 'one'),
(1, 'one'),
(2, 'two'),
(1, 'two')],
names=['foo', 'bar'])
"""
if level is not None and not is_list_like(level):
if not is_list_like(codes):
raise TypeError("Codes must be list-like")
if is_list_like(codes[0]):
raise TypeError("Codes must be list-like")
level = [level]
codes = [codes]
elif level is None or is_list_like(level):
if not is_list_like(codes) or not is_list_like(codes[0]):
raise TypeError("Codes must be list of lists-like")
if inplace:
idx = self
else:
idx = self._shallow_copy()
idx._reset_identity()
idx._set_codes(codes, level=level, verify_integrity=verify_integrity)
if not inplace:
return idx
# --------------------------------------------------------------------
# Index Internals
@cache_readonly
def _engine(self):
# Calculate the number of bits needed to represent labels in each
# level, as log2 of their sizes (including -1 for NaN):
sizes = np.ceil(np.log2([len(l) + 1 for l in self.levels]))
# Sum bit counts, starting from the _right_....
lev_bits = np.cumsum(sizes[::-1])[::-1]
# ... in order to obtain offsets such that sorting the combination of
# shifted codes (one for each level, resulting in a unique integer) is
# equivalent to sorting lexicographically the codes themselves. Notice
# that each level needs to be shifted by the number of bits needed to
# represent the _previous_ ones:
offsets = np.concatenate([lev_bits[1:], [0]]).astype("uint64")
# Check the total number of bits needed for our representation:
if lev_bits[0] > 64:
# The levels would overflow a 64 bit uint - use Python integers:
return MultiIndexPyIntEngine(self.levels, self.codes, offsets)
return MultiIndexUIntEngine(self.levels, self.codes, offsets)
@property
def _constructor(self):
return MultiIndex.from_tuples
@Appender(Index._shallow_copy.__doc__)
def _shallow_copy(self, values=None, **kwargs):
if values is not None:
names = kwargs.pop("names", kwargs.pop("name", self.names))
# discards freq
kwargs.pop("freq", None)
return MultiIndex.from_tuples(values, names=names, **kwargs)
result = self.copy(**kwargs)
result._cache = self._cache.copy()
# GH32669
if "levels" in result._cache:
del result._cache["levels"]
return result
def _shallow_copy_with_infer(self, values, **kwargs):
# On equal MultiIndexes the difference is empty.
# Therefore, an empty MultiIndex is returned GH13490
if len(values) == 0:
return MultiIndex(
levels=[[] for _ in range(self.nlevels)],
codes=[[] for _ in range(self.nlevels)],
**kwargs,
)
return self._shallow_copy(values, **kwargs)
# --------------------------------------------------------------------
def copy(
self,
names=None,
dtype=None,
levels=None,
codes=None,
deep=False,
name=None,
_set_identity=False,
):
"""
Make a copy of this object. Names, dtype, levels and codes can be
passed and will be set on new copy.
Parameters
----------
names : sequence, optional
dtype : numpy dtype or pandas type, optional
levels : sequence, optional
codes : sequence, optional
deep : bool, default False
name : Label
Kept for compatibility with 1-dimensional Index. Should not be used.
Returns
-------
MultiIndex
Notes
-----
In most cases, there should be no functional difference from using
``deep``, but if ``deep`` is passed it will attempt to deepcopy.
This could be potentially expensive on large MultiIndex objects.
"""
names = self._validate_names(name=name, names=names, deep=deep)
if deep:
from copy import deepcopy
if levels is None:
levels = deepcopy(self.levels)
if codes is None:
codes = deepcopy(self.codes)
else:
if levels is None:
levels = self.levels
if codes is None:
codes = self.codes
return MultiIndex(
levels=levels,
codes=codes,
names=names,
sortorder=self.sortorder,
verify_integrity=False,
_set_identity=_set_identity,
)
def __array__(self, dtype=None) -> np.ndarray:
""" the array interface, return my values """
return self.values
def view(self, cls=None):
""" this is defined as a copy with the same identity """
result = self.copy()
result._id = self._id
return result
@Appender(Index.__contains__.__doc__)
def __contains__(self, key: Any) -> bool:
hash(key)
try:
self.get_loc(key)
return True
except (LookupError, TypeError, ValueError):
return False
@cache_readonly
def dtype(self) -> np.dtype:
return np.dtype("O")
def _is_memory_usage_qualified(self) -> bool:
""" return a boolean if we need a qualified .info display """
def f(l):
return "mixed" in l or "string" in l or "unicode" in l
return any(f(l) for l in self._inferred_type_levels)
@Appender(Index.memory_usage.__doc__)
def memory_usage(self, deep: bool = False) -> int:
# we are overwriting our base class to avoid
# computing .values here which could materialize
# a tuple representation unnecessarily
return self._nbytes(deep)
@cache_readonly
def nbytes(self) -> int:
""" return the number of bytes in the underlying data """
return self._nbytes(False)
def _nbytes(self, deep: bool = False) -> int:
"""
return the number of bytes in the underlying data
deeply introspect the level data if deep=True
include the engine hashtable
*this is in internal routine*
"""
# for implementations with no useful getsizeof (PyPy)
objsize = 24
level_nbytes = sum(i.memory_usage(deep=deep) for i in self.levels)
label_nbytes = sum(i.nbytes for i in self.codes)
names_nbytes = sum(getsizeof(i, objsize) for i in self.names)
result = level_nbytes + label_nbytes + names_nbytes
# include our engine hashtable
result += self._engine.sizeof(deep=deep)
return result
# --------------------------------------------------------------------
# Rendering Methods
def _formatter_func(self, tup):
"""
Formats each item in tup according to its level's formatter function.
"""
formatter_funcs = [level._formatter_func for level in self.levels]
return tuple(func(val) for func, val in zip(formatter_funcs, tup))
def _format_data(self, name=None):
"""
Return the formatted data as a unicode string
"""
return format_object_summary(
self, self._formatter_func, name=name, line_break_each_value=True
)
def _format_attrs(self):
"""
Return a list of tuples of the (attr,formatted_value).
"""
return format_object_attrs(self, include_dtype=False)
def _format_native_types(self, na_rep="nan", **kwargs):
new_levels = []
new_codes = []
# go through the levels and format them
for level, level_codes in zip(self.levels, self.codes):
level = level._format_native_types(na_rep=na_rep, **kwargs)
# add nan values, if there are any
mask = level_codes == -1
if mask.any():
nan_index = len(level)
level = np.append(level, na_rep)
assert not level_codes.flags.writeable # i.e. copy is needed
level_codes = level_codes.copy() # make writeable
level_codes[mask] = nan_index
new_levels.append(level)
new_codes.append(level_codes)
if len(new_levels) == 1:
# a single-level multi-index
return Index(new_levels[0].take(new_codes[0]))._format_native_types()
else:
# reconstruct the multi-index
mi = MultiIndex(
levels=new_levels,
codes=new_codes,
names=self.names,
sortorder=self.sortorder,
verify_integrity=False,
)
return mi._values
def format(
self,
space=2,
sparsify=None,
adjoin=True,
names=False,
na_rep=None,
formatter=None,
):
if len(self) == 0:
return []
stringified_levels = []
for lev, level_codes in zip(self.levels, self.codes):
na = na_rep if na_rep is not None else _get_na_rep(lev.dtype.type)
if len(lev) > 0:
formatted = lev.take(level_codes).format(formatter=formatter)
# we have some NA
mask = level_codes == -1
if mask.any():
formatted = np.array(formatted, dtype=object)
formatted[mask] = na
formatted = formatted.tolist()
else:
# weird all NA case
formatted = [
pprint_thing(na if isna(x) else x, escape_chars=("\t", "\r", "\n"))
for x in algos.take_1d(lev._values, level_codes)
]
stringified_levels.append(formatted)
result_levels = []
for lev, name in zip(stringified_levels, self.names):
level = []
if names:
level.append(
pprint_thing(name, escape_chars=("\t", "\r", "\n"))
if name is not None
else ""
)
level.extend(np.array(lev, dtype=object))
result_levels.append(level)
if sparsify is None:
sparsify = get_option("display.multi_sparse")
if sparsify:
sentinel = ""
# GH3547
# use value of sparsify as sentinel, unless it's an obvious
# "Truthy" value
if sparsify not in [True, 1]:
sentinel = sparsify
# little bit of a kludge job for #1217
result_levels = _sparsify(
result_levels, start=int(names), sentinel=sentinel
)
if adjoin:
from pandas.io.formats.format import _get_adjustment
adj = _get_adjustment()
return adj.adjoin(space, *result_levels).split("\n")
else:
return result_levels
# --------------------------------------------------------------------
# Names Methods
def _get_names(self):
return FrozenList(self._names)
def _set_names(self, names, level=None, validate=True):
"""
Set new names on index. Each name has to be a hashable type.
Parameters
----------
values : str or sequence
name(s) to set
level : int, level name, or sequence of int/level names (default None)
If the index is a MultiIndex (hierarchical), level(s) to set (None
for all levels). Otherwise level must be None
validate : boolean, default True
validate that the names match level lengths
Raises
------
TypeError if each name is not hashable.
Notes
-----
sets names on levels. WARNING: mutates!
Note that you generally want to set this *after* changing levels, so
that it only acts on copies
"""
# GH 15110
# Don't allow a single string for names in a MultiIndex
if names is not None and not is_list_like(names):
raise ValueError("Names should be list-like for a MultiIndex")
names = list(names)
if validate:
if level is not None and len(names) != len(level):
raise ValueError("Length of names must match length of level.")
if level is None and len(names) != self.nlevels:
raise ValueError(
"Length of names must match number of levels in MultiIndex."
)
if level is None:
level = range(self.nlevels)
else:
level = [self._get_level_number(lev) for lev in level]
# set the name
for lev, name in zip(level, names):
if name is not None:
# GH 20527
# All items in 'names' need to be hashable:
if not is_hashable(name):
raise TypeError(
f"{type(self).__name__}.name must be a hashable type"
)
self._names[lev] = name
# If .levels has been accessed, the names in our cache will be stale.
self._reset_cache()
names = property(
fset=_set_names, fget=_get_names, doc="""\nNames of levels in MultiIndex.\n"""
)
# --------------------------------------------------------------------
@Appender(Index._get_grouper_for_level.__doc__)
def _get_grouper_for_level(self, mapper, level):
indexer = self.codes[level]
level_index = self.levels[level]
if mapper is not None:
# Handle group mapping function and return
level_values = self.levels[level].take(indexer)
grouper = level_values.map(mapper)
return grouper, None, None
codes, uniques = algos.factorize(indexer, sort=True)
if len(uniques) > 0 and uniques[0] == -1:
# Handle NAs
mask = indexer != -1
ok_codes, uniques = algos.factorize(indexer[mask], sort=True)
codes = np.empty(len(indexer), dtype=indexer.dtype)
codes[mask] = ok_codes
codes[~mask] = -1
if len(uniques) < len(level_index):
# Remove unobserved levels from level_index
level_index = level_index.take(uniques)
else:
# break references back to us so that setting the name
# on the output of a groupby doesn't reflect back here.
level_index = level_index.copy()
if level_index._can_hold_na:
grouper = level_index.take(codes, fill_value=True)
else:
grouper = level_index.take(codes)
return grouper, codes, level_index
@cache_readonly
def inferred_type(self) -> str:
return "mixed"
def _get_level_number(self, level) -> int:
count = self.names.count(level)
if (count > 1) and not is_integer(level):
raise ValueError(
f"The name {level} occurs multiple times, use a level number"
)
try:
level = self.names.index(level)
except ValueError as err:
if not is_integer(level):
raise KeyError(f"Level {level} not found") from err
elif level < 0:
level += self.nlevels
if level < 0:
orig_level = level - self.nlevels
raise IndexError(
f"Too many levels: Index has only {self.nlevels} levels, "
f"{orig_level} is not a valid level number"
) from err
# Note: levels are zero-based
elif level >= self.nlevels:
raise IndexError(
f"Too many levels: Index has only {self.nlevels} levels, "
f"not {level + 1}"
) from err
return level
@property
def _has_complex_internals(self) -> bool:
# used to avoid libreduction code paths, which raise or require conversion
return True
@cache_readonly
def is_monotonic_increasing(self) -> bool:
"""
return if the index is monotonic increasing (only equal or
increasing) values.
"""
if all(x.is_monotonic for x in self.levels):
# If each level is sorted, we can operate on the codes directly. GH27495
return libalgos.is_lexsorted(
[x.astype("int64", copy=False) for x in self.codes]
)
# reversed() because lexsort() wants the most significant key last.
values = [
self._get_level_values(i).values for i in reversed(range(len(self.levels)))
]
try:
sort_order = np.lexsort(values)
return Index(sort_order).is_monotonic
except TypeError:
# we have mixed types and np.lexsort is not happy
return Index(self._values).is_monotonic
@cache_readonly
def is_monotonic_decreasing(self) -> bool:
"""
return if the index is monotonic decreasing (only equal or
decreasing) values.
"""
# monotonic decreasing if and only if reverse is monotonic increasing
return self[::-1].is_monotonic_increasing
@cache_readonly
def _inferred_type_levels(self):
""" return a list of the inferred types, one for each level """
return [i.inferred_type for i in self.levels]
@Appender(Index.duplicated.__doc__)
def duplicated(self, keep="first"):
shape = map(len, self.levels)
ids = get_group_index(self.codes, shape, sort=False, xnull=False)
return duplicated_int64(ids, keep)
def fillna(self, value=None, downcast=None):
"""
fillna is not implemented for MultiIndex
"""
raise NotImplementedError("isna is not defined for MultiIndex")
@Appender(Index.dropna.__doc__)
def dropna(self, how="any"):
nans = [level_codes == -1 for level_codes in self.codes]
if how == "any":
indexer = np.any(nans, axis=0)
elif how == "all":
indexer = np.all(nans, axis=0)
else:
raise ValueError(f"invalid how option: {how}")
new_codes = [level_codes[~indexer] for level_codes in self.codes]
return self.copy(codes=new_codes, deep=True)
def _get_level_values(self, level, unique=False):
"""
Return vector of label values for requested level,
equal to the length of the index
**this is an internal method**
Parameters
----------
level : int level
unique : bool, default False
if True, drop duplicated values
Returns
-------
values : ndarray
"""
lev = self.levels[level]
level_codes = self.codes[level]
name = self._names[level]
if unique:
level_codes = algos.unique(level_codes)
filled = algos.take_1d(lev._values, level_codes, fill_value=lev._na_value)
return lev._shallow_copy(filled, name=name)
def get_level_values(self, level):
"""
Return vector of label values for requested level,
equal to the length of the index.
Parameters
----------
level : int or str
``level`` is either the integer position of the level in the
MultiIndex, or the name of the level.
Returns
-------
values : Index
Values is a level of this MultiIndex converted to
a single :class:`Index` (or subclass thereof).
Examples
--------
Create a MultiIndex:
>>> mi = pd.MultiIndex.from_arrays((list('abc'), list('def')))
>>> mi.names = ['level_1', 'level_2']
Get level values by supplying level as either integer or name:
>>> mi.get_level_values(0)
Index(['a', 'b', 'c'], dtype='object', name='level_1')
>>> mi.get_level_values('level_2')
Index(['d', 'e', 'f'], dtype='object', name='level_2')
"""
level = self._get_level_number(level)
values = self._get_level_values(level)
return values
@Appender(Index.unique.__doc__)
def unique(self, level=None):
if level is None:
return super().unique()
else:
level = self._get_level_number(level)
return self._get_level_values(level=level, unique=True)
def _to_safe_for_reshape(self):
""" convert to object if we are a categorical """
return self.set_levels([i._to_safe_for_reshape() for i in self.levels])
def to_frame(self, index=True, name=None):
"""
Create a DataFrame with the levels of the MultiIndex as columns.
Column ordering is determined by the DataFrame constructor with data as
a dict.
.. versionadded:: 0.24.0
Parameters
----------
index : bool, default True
Set the index of the returned DataFrame as the original MultiIndex.
name : list / sequence of str, optional
The passed names should substitute index level names.
Returns
-------
DataFrame : a DataFrame containing the original MultiIndex data.
See Also
--------
DataFrame
"""
from pandas import DataFrame
if name is not None:
if not is_list_like(name):
raise TypeError("'name' must be a list / sequence of column names.")
if len(name) != len(self.levels):
raise ValueError(
"'name' should have same length as number of levels on index."
)
idx_names = name
else:
idx_names = self.names
# Guarantee resulting column order - PY36+ dict maintains insertion order
result = DataFrame(
{
(level if lvlname is None else lvlname): self._get_level_values(level)
for lvlname, level in zip(idx_names, range(len(self.levels)))
},
copy=False,
)
if index:
result.index = self
return result
def to_flat_index(self):
"""
Convert a MultiIndex to an Index of Tuples containing the level values.
.. versionadded:: 0.24.0
Returns
-------
pd.Index
Index with the MultiIndex data represented in Tuples.
Notes
-----
This method will simply return the caller if called by anything other
than a MultiIndex.
Examples
--------
>>> index = pd.MultiIndex.from_product(
... [['foo', 'bar'], ['baz', 'qux']],
... names=['a', 'b'])
>>> index.to_flat_index()
Index([('foo', 'baz'), ('foo', 'qux'),
('bar', 'baz'), ('bar', 'qux')],
dtype='object')
"""
return Index(self._values, tupleize_cols=False)
@property
def is_all_dates(self) -> bool:
return False
def is_lexsorted(self) -> bool:
"""
Return True if the codes are lexicographically sorted.
Returns
-------
bool
"""
return self.lexsort_depth == self.nlevels
@cache_readonly
def lexsort_depth(self):
if self.sortorder is not None:
return self.sortorder
return self._lexsort_depth()
def _lexsort_depth(self) -> int:
"""
Compute and return the lexsort_depth, the number of levels of the
MultiIndex that are sorted lexically
Returns
-------
int
"""
int64_codes = [ensure_int64(level_codes) for level_codes in self.codes]
for k in range(self.nlevels, 0, -1):
if libalgos.is_lexsorted(int64_codes[:k]):
return k
return 0
def _sort_levels_monotonic(self):
"""
This is an *internal* function.
Create a new MultiIndex from the current to monotonically sorted
items IN the levels. This does not actually make the entire MultiIndex
monotonic, JUST the levels.
The resulting MultiIndex will have the same outward
appearance, meaning the same .values and ordering. It will also
be .equals() to the original.
Returns
-------
MultiIndex
Examples
--------
>>> mi = pd.MultiIndex(levels=[['a', 'b'], ['bb', 'aa']],
... codes=[[0, 0, 1, 1], [0, 1, 0, 1]])
>>> mi
MultiIndex([('a', 'bb'),
('a', 'aa'),
('b', 'bb'),
('b', 'aa')],
)
>>> mi.sort_values()
MultiIndex([('a', 'aa'),
('a', 'bb'),
('b', 'aa'),
('b', 'bb')],
)
"""
if self.is_lexsorted() and self.is_monotonic:
return self
new_levels = []
new_codes = []
for lev, level_codes in zip(self.levels, self.codes):
if not lev.is_monotonic:
try:
# indexer to reorder the levels
indexer = lev.argsort()
except TypeError:
pass
else:
lev = lev.take(indexer)
# indexer to reorder the level codes
indexer = ensure_int64(indexer)
ri = lib.get_reverse_indexer(indexer, len(indexer))
level_codes = algos.take_1d(ri, level_codes)
new_levels.append(lev)
new_codes.append(level_codes)
return MultiIndex(
new_levels,
new_codes,
names=self.names,
sortorder=self.sortorder,
verify_integrity=False,
)
def remove_unused_levels(self):
"""
Create a new MultiIndex from the current that removes
unused levels, meaning that they are not expressed in the labels.
The resulting MultiIndex will have the same outward
appearance, meaning the same .values and ordering. It will also
be .equals() to the original.
Returns
-------
MultiIndex
Examples
--------
>>> mi = pd.MultiIndex.from_product([range(2), list('ab')])
>>> mi
MultiIndex([(0, 'a'),
(0, 'b'),
(1, 'a'),
(1, 'b')],
)
>>> mi[2:]
MultiIndex([(1, 'a'),
(1, 'b')],
)
The 0 from the first level is not represented
and can be removed
>>> mi2 = mi[2:].remove_unused_levels()
>>> mi2.levels
FrozenList([[1], ['a', 'b']])
"""
new_levels = []
new_codes = []
changed = False
for lev, level_codes in zip(self.levels, self.codes):
# Since few levels are typically unused, bincount() is more
# efficient than unique() - however it only accepts positive values
# (and drops order):
uniques = np.where(np.bincount(level_codes + 1) > 0)[0] - 1
has_na = int(len(uniques) and (uniques[0] == -1))
if len(uniques) != len(lev) + has_na:
# We have unused levels
changed = True
# Recalculate uniques, now preserving order.
# Can easily be cythonized by exploiting the already existing
# "uniques" and stop parsing "level_codes" when all items
# are found:
uniques = algos.unique(level_codes)
if has_na:
na_idx = np.where(uniques == -1)[0]
# Just ensure that -1 is in first position:
uniques[[0, na_idx[0]]] = uniques[[na_idx[0], 0]]
# codes get mapped from uniques to 0:len(uniques)
# -1 (if present) is mapped to last position
code_mapping = np.zeros(len(lev) + has_na)
# ... and reassigned value -1:
code_mapping[uniques] = np.arange(len(uniques)) - has_na
level_codes = code_mapping[level_codes]
# new levels are simple
lev = lev.take(uniques[has_na:])
new_levels.append(lev)
new_codes.append(level_codes)
result = self.view()
if changed:
result._reset_identity()
result._set_levels(new_levels, validate=False)
result._set_codes(new_codes, validate=False)
return result
# --------------------------------------------------------------------
# Pickling Methods
def __reduce__(self):
"""Necessary for making this object picklable"""
d = dict(
levels=list(self.levels),
codes=list(self.codes),
sortorder=self.sortorder,
names=list(self.names),
)
return ibase._new_Index, (type(self), d), None
# --------------------------------------------------------------------
def __getitem__(self, key):
if is_scalar(key):
key = com.cast_scalar_indexer(key)
retval = []
for lev, level_codes in zip(self.levels, self.codes):
if level_codes[key] == -1:
retval.append(np.nan)
else:
retval.append(lev[level_codes[key]])
return tuple(retval)
else:
if com.is_bool_indexer(key):
key = np.asarray(key, dtype=bool)
sortorder = self.sortorder
else:
# cannot be sure whether the result will be sorted
sortorder = None
if isinstance(key, Index):
key = np.asarray(key)
new_codes = [level_codes[key] for level_codes in self.codes]
return MultiIndex(
levels=self.levels,
codes=new_codes,
names=self.names,
sortorder=sortorder,
verify_integrity=False,
)
@Appender(_index_shared_docs["take"] % _index_doc_kwargs)
def take(self, indices, axis=0, allow_fill=True, fill_value=None, **kwargs):
nv.validate_take(tuple(), kwargs)
indices = ensure_platform_int(indices)
taken = self._assert_take_fillable(
self.codes,
indices,
allow_fill=allow_fill,
fill_value=fill_value,
na_value=-1,
)
return MultiIndex(
levels=self.levels, codes=taken, names=self.names, verify_integrity=False
)
def _assert_take_fillable(
self, values, indices, allow_fill=True, fill_value=None, na_value=None
):
""" Internal method to handle NA filling of take """
# only fill if we are passing a non-None fill_value
if allow_fill and fill_value is not None:
if (indices < -1).any():
msg = (
"When allow_fill=True and fill_value is not None, "
"all indices must be >= -1"
)
raise ValueError(msg)
taken = [lab.take(indices) for lab in self.codes]
mask = indices == -1
if mask.any():
masked = []
for new_label in taken:
label_values = new_label
label_values[mask] = na_value
masked.append(np.asarray(label_values))
taken = masked
else:
taken = [lab.take(indices) for lab in self.codes]
return taken
def append(self, other):
"""
Append a collection of Index options together
Parameters
----------
other : Index or list/tuple of indices
Returns
-------
appended : Index
"""
if not isinstance(other, (list, tuple)):
other = [other]
if all(
(isinstance(o, MultiIndex) and o.nlevels >= self.nlevels) for o in other
):
arrays = []
for i in range(self.nlevels):
label = self._get_level_values(i)
appended = [o._get_level_values(i) for o in other]
arrays.append(label.append(appended))
return MultiIndex.from_arrays(arrays, names=self.names)
to_concat = (self._values,) + tuple(k._values for k in other)
new_tuples = np.concatenate(to_concat)
# if all(isinstance(x, MultiIndex) for x in other):
try:
return MultiIndex.from_tuples(new_tuples, names=self.names)
except (TypeError, IndexError):
return Index(new_tuples)
def argsort(self, *args, **kwargs) -> np.ndarray:
return self._values.argsort(*args, **kwargs)
@Appender(_index_shared_docs["repeat"] % _index_doc_kwargs)
def repeat(self, repeats, axis=None):
nv.validate_repeat(tuple(), dict(axis=axis))
repeats = ensure_platform_int(repeats)
return MultiIndex(
levels=self.levels,
codes=[
level_codes.view(np.ndarray).astype(np.intp).repeat(repeats)
for level_codes in self.codes
],
names=self.names,
sortorder=self.sortorder,
verify_integrity=False,
)
def where(self, cond, other=None):
raise NotImplementedError(".where is not supported for MultiIndex operations")
def drop(self, codes, level=None, errors="raise"):
"""
Make new MultiIndex with passed list of codes deleted
Parameters
----------
codes : array-like
Must be a list of tuples
level : int or level name, default None
errors : str, default 'raise'
Returns
-------
dropped : MultiIndex
"""
if level is not None:
return self._drop_from_level(codes, level, errors)
if not isinstance(codes, (np.ndarray, Index)):
try:
codes = com.index_labels_to_array(codes, dtype=object)
except ValueError:
pass
inds = []
for level_codes in codes:
try:
loc = self.get_loc(level_codes)
# get_loc returns either an integer, a slice, or a boolean
# mask
if isinstance(loc, int):
inds.append(loc)
elif isinstance(loc, slice):
inds.extend(range(loc.start, loc.stop))
elif com.is_bool_indexer(loc):
if self.lexsort_depth == 0:
warnings.warn(
"dropping on a non-lexsorted multi-index "
"without a level parameter may impact performance.",
PerformanceWarning,
stacklevel=3,
)
loc = loc.nonzero()[0]
inds.extend(loc)
else:
msg = f"unsupported indexer of type {type(loc)}"
raise AssertionError(msg)
except KeyError:
if errors != "ignore":
raise
return self.delete(inds)
def _drop_from_level(self, codes, level, errors="raise"):
codes = com.index_labels_to_array(codes)
i = self._get_level_number(level)
index = self.levels[i]
values = index.get_indexer(codes)
mask = ~algos.isin(self.codes[i], values)
if mask.all() and errors != "ignore":
raise KeyError(f"labels {codes} not found in level")
return self[mask]
def swaplevel(self, i=-2, j=-1):
"""
Swap level i with level j.
Calling this method does not change the ordering of the values.
Parameters
----------
i : int, str, default -2
First level of index to be swapped. Can pass level name as string.
Type of parameters can be mixed.
j : int, str, default -1
Second level of index to be swapped. Can pass level name as string.
Type of parameters can be mixed.
Returns
-------
MultiIndex
A new MultiIndex.
See Also
--------
Series.swaplevel : Swap levels i and j in a MultiIndex.
Dataframe.swaplevel : Swap levels i and j in a MultiIndex on a
particular axis.
Examples
--------
>>> mi = pd.MultiIndex(levels=[['a', 'b'], ['bb', 'aa']],
... codes=[[0, 0, 1, 1], [0, 1, 0, 1]])
>>> mi
MultiIndex([('a', 'bb'),
('a', 'aa'),
('b', 'bb'),
('b', 'aa')],
)
>>> mi.swaplevel(0, 1)
MultiIndex([('bb', 'a'),
('aa', 'a'),
('bb', 'b'),
('aa', 'b')],
)
"""
new_levels = list(self.levels)
new_codes = list(self.codes)
new_names = list(self.names)
i = self._get_level_number(i)
j = self._get_level_number(j)
new_levels[i], new_levels[j] = new_levels[j], new_levels[i]
new_codes[i], new_codes[j] = new_codes[j], new_codes[i]
new_names[i], new_names[j] = new_names[j], new_names[i]
return MultiIndex(
levels=new_levels, codes=new_codes, names=new_names, verify_integrity=False
)
def reorder_levels(self, order):
"""
Rearrange levels using input order. May not drop or duplicate levels.
Parameters
----------
order : list of int or list of str
List representing new level order. Reference level by number
(position) or by key (label).
Returns
-------
MultiIndex
"""
order = [self._get_level_number(i) for i in order]
if len(order) != self.nlevels:
raise AssertionError(
f"Length of order must be same as number of levels ({self.nlevels}), "
f"got {len(order)}"
)
new_levels = [self.levels[i] for i in order]
new_codes = [self.codes[i] for i in order]
new_names = [self.names[i] for i in order]
return MultiIndex(
levels=new_levels, codes=new_codes, names=new_names, verify_integrity=False
)
def _get_codes_for_sorting(self):
"""
we categorizing our codes by using the
available categories (all, not just observed)
excluding any missing ones (-1); this is in preparation
for sorting, where we need to disambiguate that -1 is not
a valid valid
"""
def cats(level_codes):
return np.arange(
np.array(level_codes).max() + 1 if len(level_codes) else 0,
dtype=level_codes.dtype,
)
return [
Categorical.from_codes(level_codes, cats(level_codes), ordered=True)
for level_codes in self.codes
]
def sortlevel(self, level=0, ascending=True, sort_remaining=True):
"""
Sort MultiIndex at the requested level. The result will respect the
original ordering of the associated factor at that level.
Parameters
----------
level : list-like, int or str, default 0
If a string is given, must be a name of the level.
If list-like must be names or ints of levels.
ascending : bool, default True
False to sort in descending order.
Can also be a list to specify a directed ordering.
sort_remaining : sort by the remaining levels after level
Returns
-------
sorted_index : pd.MultiIndex
Resulting index.
indexer : np.ndarray
Indices of output values in original index.
"""
if isinstance(level, (str, int)):
level = [level]
level = [self._get_level_number(lev) for lev in level]
sortorder = None
# we have a directed ordering via ascending
if isinstance(ascending, list):
if not len(level) == len(ascending):
raise ValueError("level must have same length as ascending")
indexer = lexsort_indexer(
[self.codes[lev] for lev in level], orders=ascending
)
# level ordering
else:
codes = list(self.codes)
shape = list(self.levshape)
# partition codes and shape
primary = tuple(codes[lev] for lev in level)
primshp = tuple(shape[lev] for lev in level)
# Reverse sorted to retain the order of
# smaller indices that needs to be removed
for lev in sorted(level, reverse=True):
codes.pop(lev)
shape.pop(lev)
if sort_remaining:
primary += primary + tuple(codes)
primshp += primshp + tuple(shape)
else:
sortorder = level[0]
indexer = indexer_from_factorized(primary, primshp, compress=False)
if not ascending:
indexer = indexer[::-1]
indexer = ensure_platform_int(indexer)
new_codes = [level_codes.take(indexer) for level_codes in self.codes]
new_index = MultiIndex(
codes=new_codes,
levels=self.levels,
names=self.names,
sortorder=sortorder,
verify_integrity=False,
)
return new_index, indexer
def reindex(self, target, method=None, level=None, limit=None, tolerance=None):
"""
Create index with target's values (move/add/delete values as necessary)
Returns
-------
new_index : pd.MultiIndex
Resulting index
indexer : np.ndarray or None
Indices of output values in original index.
"""
# GH6552: preserve names when reindexing to non-named target
# (i.e. neither Index nor Series).
preserve_names = not hasattr(target, "names")
if level is not None:
if method is not None:
raise TypeError("Fill method not supported if level passed")
# GH7774: preserve dtype/tz if target is empty and not an Index.
# target may be an iterator
target = ibase._ensure_has_len(target)
if len(target) == 0 and not isinstance(target, Index):
idx = self.levels[level]
attrs = idx._get_attributes_dict()
attrs.pop("freq", None) # don't preserve freq
target = type(idx)._simple_new(np.empty(0, dtype=idx.dtype), **attrs)
else:
target = ensure_index(target)
target, indexer, _ = self._join_level(
target, level, how="right", return_indexers=True, keep_order=False
)
else:
target = ensure_index(target)
if self.equals(target):
indexer = None
else:
if self.is_unique:
indexer = self.get_indexer(
target, method=method, limit=limit, tolerance=tolerance
)
else:
raise ValueError("cannot handle a non-unique multi-index!")
if not isinstance(target, MultiIndex):
if indexer is None:
target = self
elif (indexer >= 0).all():
target = self.take(indexer)
else:
# hopefully?
target = MultiIndex.from_tuples(target)
if (
preserve_names
and target.nlevels == self.nlevels
and target.names != self.names
):
target = target.copy(deep=False)
target.names = self.names
return target, indexer
# --------------------------------------------------------------------
# Indexing Methods
def get_value(self, series, key):
# Label-based
if not is_hashable(key) or is_iterator(key):
# We allow tuples if they are hashable, whereas other Index
# subclasses require scalar.
# We have to explicitly exclude generators, as these are hashable.
raise InvalidIndexError(key)
try:
loc = self.get_loc(key)
except KeyError:
if is_integer(key):
loc = key
else:
raise
return self._get_values_for_loc(series, loc, key)
def _get_values_for_loc(self, series: "Series", loc, key):
"""
Do a positional lookup on the given Series, returning either a scalar
or a Series.
Assumes that `series.index is self`
"""
new_values = series._values[loc]
if is_scalar(loc):
return new_values
new_index = self[loc]
new_index = maybe_droplevels(new_index, key)
new_ser = series._constructor(new_values, index=new_index, name=series.name)
return new_ser.__finalize__(series)
def _convert_listlike_indexer(self, keyarr):
"""
Parameters
----------
keyarr : list-like
Indexer to convert.
Returns
-------
tuple (indexer, keyarr)
indexer is an ndarray or None if cannot convert
keyarr are tuple-safe keys
"""
indexer, keyarr = super()._convert_listlike_indexer(keyarr)
# are we indexing a specific level
if indexer is None and len(keyarr) and not isinstance(keyarr[0], tuple):
level = 0
_, indexer = self.reindex(keyarr, level=level)
# take all
if indexer is None:
indexer = np.arange(len(self))
check = self.levels[0].get_indexer(keyarr)
mask = check == -1
if mask.any():
raise KeyError(f"{keyarr[mask]} not in index")
return indexer, keyarr
def _get_partial_string_timestamp_match_key(self, key):
"""
Translate any partial string timestamp matches in key, returning the
new key.
Only relevant for MultiIndex.
"""
# GH#10331
if isinstance(key, str) and self.levels[0]._supports_partial_string_indexing:
# Convert key '2016-01-01' to
# ('2016-01-01'[, slice(None, None, None)]+)
key = tuple([key] + [slice(None)] * (len(self.levels) - 1))
if isinstance(key, tuple):
# Convert (..., '2016-01-01', ...) in tuple to
# (..., slice('2016-01-01', '2016-01-01', None), ...)
new_key = []
for i, component in enumerate(key):
if (
isinstance(component, str)
and self.levels[i]._supports_partial_string_indexing
):
new_key.append(slice(component, component, None))
else:
new_key.append(component)
key = tuple(new_key)
return key
@Appender(_index_shared_docs["get_indexer"] % _index_doc_kwargs)
def get_indexer(self, target, method=None, limit=None, tolerance=None):
method = missing.clean_reindex_fill_method(method)
target = ensure_index(target)
# empty indexer
if is_list_like(target) and not len(target):
return ensure_platform_int(np.array([]))
if not isinstance(target, MultiIndex):
try:
target = MultiIndex.from_tuples(target)
except (TypeError, ValueError):
# let's instead try with a straight Index
if method is None:
return Index(self._values).get_indexer(
target, method=method, limit=limit, tolerance=tolerance
)
if not self.is_unique:
raise ValueError("Reindexing only valid with uniquely valued Index objects")
if method == "pad" or method == "backfill":
if tolerance is not None:
raise NotImplementedError(
"tolerance not implemented yet for MultiIndex"
)
indexer = self._engine.get_indexer(target, method, limit)
elif method == "nearest":
raise NotImplementedError(
"method='nearest' not implemented yet "
"for MultiIndex; see GitHub issue 9365"
)
else:
indexer = self._engine.get_indexer(target)
return ensure_platform_int(indexer)
@Appender(_index_shared_docs["get_indexer_non_unique"] % _index_doc_kwargs)
def get_indexer_non_unique(self, target):
return super().get_indexer_non_unique(target)
def get_slice_bound(
self, label: Union[Hashable, Sequence[Hashable]], side: str, kind: str
) -> int:
"""
For an ordered MultiIndex, compute slice bound
that corresponds to given label.
Returns leftmost (one-past-the-rightmost if `side=='right') position
of given label.
Parameters
----------
label : object or tuple of objects
side : {'left', 'right'}
kind : {'loc', 'getitem'}
Returns
-------
int
Index of label.
Notes
-----
This method only works if level 0 index of the MultiIndex is lexsorted.
Examples
--------
>>> mi = pd.MultiIndex.from_arrays([list('abbc'), list('gefd')])
Get the locations from the leftmost 'b' in the first level
until the end of the multiindex:
>>> mi.get_slice_bound('b', side="left", kind="loc")
1
Like above, but if you get the locations from the rightmost
'b' in the first level and 'f' in the second level:
>>> mi.get_slice_bound(('b','f'), side="right", kind="loc")
3
See Also
--------
MultiIndex.get_loc : Get location for a label or a tuple of labels.
MultiIndex.get_locs : Get location for a label/slice/list/mask or a
sequence of such.
"""
if not isinstance(label, tuple):
label = (label,)
return self._partial_tup_index(label, side=side)
def slice_locs(self, start=None, end=None, step=None, kind=None):
"""
For an ordered MultiIndex, compute the slice locations for input
labels.
The input labels can be tuples representing partial levels, e.g. for a
MultiIndex with 3 levels, you can pass a single value (corresponding to
the first level), or a 1-, 2-, or 3-tuple.
Parameters
----------
start : label or tuple, default None
If None, defaults to the beginning
end : label or tuple
If None, defaults to the end
step : int or None
Slice step
kind : string, optional, defaults None
Returns
-------
(start, end) : (int, int)
Notes
-----
This method only works if the MultiIndex is properly lexsorted. So,
if only the first 2 levels of a 3-level MultiIndex are lexsorted,
you can only pass two levels to ``.slice_locs``.
Examples
--------
>>> mi = pd.MultiIndex.from_arrays([list('abbd'), list('deff')],
... names=['A', 'B'])
Get the slice locations from the beginning of 'b' in the first level
until the end of the multiindex:
>>> mi.slice_locs(start='b')
(1, 4)
Like above, but stop at the end of 'b' in the first level and 'f' in
the second level:
>>> mi.slice_locs(start='b', end=('b', 'f'))
(1, 3)
See Also
--------
MultiIndex.get_loc : Get location for a label or a tuple of labels.
MultiIndex.get_locs : Get location for a label/slice/list/mask or a
sequence of such.
"""
# This function adds nothing to its parent implementation (the magic
# happens in get_slice_bound method), but it adds meaningful doc.
return super().slice_locs(start, end, step, kind=kind)
def _partial_tup_index(self, tup, side="left"):
if len(tup) > self.lexsort_depth:
raise UnsortedIndexError(
f"Key length ({len(tup)}) was greater than MultiIndex lexsort depth "
f"({self.lexsort_depth})"
)
n = len(tup)
start, end = 0, len(self)
zipped = zip(tup, self.levels, self.codes)
for k, (lab, lev, labs) in enumerate(zipped):
section = labs[start:end]
if lab not in lev and not isna(lab):
if not lev.is_type_compatible(lib.infer_dtype([lab], skipna=False)):
raise TypeError(f"Level type mismatch: {lab}")
# short circuit
loc = lev.searchsorted(lab, side=side)
if side == "right" and loc >= 0:
loc -= 1
return start + section.searchsorted(loc, side=side)
idx = self._get_loc_single_level_index(lev, lab)
if k < n - 1:
end = start + section.searchsorted(idx, side="right")
start = start + section.searchsorted(idx, side="left")
else:
return start + section.searchsorted(idx, side=side)
def _get_loc_single_level_index(self, level_index: Index, key: Hashable) -> int:
"""
If key is NA value, location of index unify as -1.
Parameters
----------
level_index: Index
key : label
Returns
-------
loc : int
If key is NA value, loc is -1
Else, location of key in index.
See Also
--------
Index.get_loc : The get_loc method for (single-level) index.
"""
if is_scalar(key) and isna(key):
return -1
else:
return level_index.get_loc(key)
def get_loc(self, key, method=None):
"""
Get location for a label or a tuple of labels as an integer, slice or
boolean mask.
Parameters
----------
key : label or tuple of labels (one for each level)
method : None
Returns
-------
loc : int, slice object or boolean mask
If the key is past the lexsort depth, the return may be a
boolean mask array, otherwise it is always a slice or int.
See Also
--------
Index.get_loc : The get_loc method for (single-level) index.
MultiIndex.slice_locs : Get slice location given start label(s) and
end label(s).
MultiIndex.get_locs : Get location for a label/slice/list/mask or a
sequence of such.
Notes
-----
The key cannot be a slice, list of same-level labels, a boolean mask,
or a sequence of such. If you want to use those, use
:meth:`MultiIndex.get_locs` instead.
Examples
--------
>>> mi = pd.MultiIndex.from_arrays([list('abb'), list('def')])
>>> mi.get_loc('b')
slice(1, 3, None)
>>> mi.get_loc(('b', 'e'))
1
"""
if method is not None:
raise NotImplementedError(
"only the default get_loc method is "
"currently supported for MultiIndex"
)
def _maybe_to_slice(loc):
"""convert integer indexer to boolean mask or slice if possible"""
if not isinstance(loc, np.ndarray) or loc.dtype != "int64":
return loc
loc = lib.maybe_indices_to_slice(loc, len(self))
if isinstance(loc, slice):
return loc
mask = np.empty(len(self), dtype="bool")
mask.fill(False)
mask[loc] = True
return mask
if not isinstance(key, (tuple, list)):
# not including list here breaks some indexing, xref #30892
loc = self._get_level_indexer(key, level=0)
return _maybe_to_slice(loc)
keylen = len(key)
if self.nlevels < keylen:
raise KeyError(
f"Key length ({keylen}) exceeds index depth ({self.nlevels})"
)
if keylen == self.nlevels and self.is_unique:
return self._engine.get_loc(key)
# -- partial selection or non-unique index
# break the key into 2 parts based on the lexsort_depth of the index;
# the first part returns a continuous slice of the index; the 2nd part
# needs linear search within the slice
i = self.lexsort_depth
lead_key, follow_key = key[:i], key[i:]
start, stop = (
self.slice_locs(lead_key, lead_key) if lead_key else (0, len(self))
)
if start == stop:
raise KeyError(key)
if not follow_key:
return slice(start, stop)
warnings.warn(
"indexing past lexsort depth may impact performance.",
PerformanceWarning,
stacklevel=10,
)
loc = np.arange(start, stop, dtype="int64")
for i, k in enumerate(follow_key, len(lead_key)):
mask = self.codes[i][loc] == self._get_loc_single_level_index(
self.levels[i], k
)
if not mask.all():
loc = loc[mask]
if not len(loc):
raise KeyError(key)
return _maybe_to_slice(loc) if len(loc) != stop - start else slice(start, stop)
def get_loc_level(self, key, level=0, drop_level: bool = True):
"""
Get both the location for the requested label(s) and the
resulting sliced index.
Parameters
----------
key : label or sequence of labels
level : int/level name or list thereof, optional
drop_level : bool, default True
If ``False``, the resulting index will not drop any level.
Returns
-------
loc : A 2-tuple where the elements are:
Element 0: int, slice object or boolean array
Element 1: The resulting sliced multiindex/index. If the key
contains all levels, this will be ``None``.
See Also
--------
MultiIndex.get_loc : Get location for a label or a tuple of labels.
MultiIndex.get_locs : Get location for a label/slice/list/mask or a
sequence of such.
Examples
--------
>>> mi = pd.MultiIndex.from_arrays([list('abb'), list('def')],
... names=['A', 'B'])
>>> mi.get_loc_level('b')
(slice(1, 3, None), Index(['e', 'f'], dtype='object', name='B'))
>>> mi.get_loc_level('e', level='B')
(array([False, True, False], dtype=bool),
Index(['b'], dtype='object', name='A'))
>>> mi.get_loc_level(['b', 'e'])
(1, None)
"""
# different name to distinguish from maybe_droplevels
def maybe_mi_droplevels(indexer, levels, drop_level: bool):
if not drop_level:
return self[indexer]
# kludgearound
orig_index = new_index = self[indexer]
levels = [self._get_level_number(i) for i in levels]
for i in sorted(levels, reverse=True):
try:
new_index = new_index.droplevel(i)
except ValueError:
# no dropping here
return orig_index
return new_index
if isinstance(level, (tuple, list)):
if len(key) != len(level):
raise AssertionError(
"Key for location must have same length as number of levels"
)
result = None
for lev, k in zip(level, key):
loc, new_index = self.get_loc_level(k, level=lev)
if isinstance(loc, slice):
mask = np.zeros(len(self), dtype=bool)
mask[loc] = True
loc = mask
result = loc if result is None else result & loc
return result, maybe_mi_droplevels(result, level, drop_level)
level = self._get_level_number(level)
# kludge for #1796
if isinstance(key, list):
key = tuple(key)
if isinstance(key, tuple) and level == 0:
try:
if key in self.levels[0]:
indexer = self._get_level_indexer(key, level=level)
new_index = maybe_mi_droplevels(indexer, [0], drop_level)
return indexer, new_index
except (TypeError, InvalidIndexError):
pass
if not any(isinstance(k, slice) for k in key):
# partial selection
# optionally get indexer to avoid re-calculation
def partial_selection(key, indexer=None):
if indexer is None:
indexer = self.get_loc(key)
ilevels = [
i for i in range(len(key)) if key[i] != slice(None, None)
]
return indexer, maybe_mi_droplevels(indexer, ilevels, drop_level)
if len(key) == self.nlevels and self.is_unique:
# Complete key in unique index -> standard get_loc
try:
return (self._engine.get_loc(key), None)
except KeyError as e:
raise KeyError(key) from e
else:
return partial_selection(key)
else:
indexer = None
for i, k in enumerate(key):
if not isinstance(k, slice):
k = self._get_level_indexer(k, level=i)
if isinstance(k, slice):
# everything
if k.start == 0 and k.stop == len(self):
k = slice(None, None)
else:
k_index = k
if isinstance(k, slice):
if k == slice(None, None):
continue
else:
raise TypeError(key)
if indexer is None:
indexer = k_index
else: # pragma: no cover
indexer &= k_index
if indexer is None:
indexer = slice(None, None)
ilevels = [i for i in range(len(key)) if key[i] != slice(None, None)]
return indexer, maybe_mi_droplevels(indexer, ilevels, drop_level)
else:
indexer = self._get_level_indexer(key, level=level)
return indexer, maybe_mi_droplevels(indexer, [level], drop_level)
def _get_level_indexer(self, key, level=0, indexer=None):
# return an indexer, boolean array or a slice showing where the key is
# in the totality of values
# if the indexer is provided, then use this
level_index = self.levels[level]
level_codes = self.codes[level]
def convert_indexer(start, stop, step, indexer=indexer, codes=level_codes):
# given the inputs and the codes/indexer, compute an indexer set
# if we have a provided indexer, then this need not consider
# the entire labels set
r = np.arange(start, stop, step)
if indexer is not None and len(indexer) != len(codes):
# we have an indexer which maps the locations in the labels
# that we have already selected (and is not an indexer for the
# entire set) otherwise this is wasteful so we only need to
# examine locations that are in this set the only magic here is
# that the result are the mappings to the set that we have
# selected
from pandas import Series
mapper = Series(indexer)
indexer = codes.take(ensure_platform_int(indexer))
result = Series(Index(indexer).isin(r).nonzero()[0])
m = result.map(mapper)
m = np.asarray(m)
else:
m = np.zeros(len(codes), dtype=bool)
m[np.in1d(codes, r, assume_unique=Index(codes).is_unique)] = True
return m
if isinstance(key, slice):
# handle a slice, returning a slice if we can
# otherwise a boolean indexer
try:
if key.start is not None:
start = level_index.get_loc(key.start)
else:
start = 0
if key.stop is not None:
stop = level_index.get_loc(key.stop)
else:
stop = len(level_index) - 1
step = key.step
except KeyError:
# we have a partial slice (like looking up a partial date
# string)
start = stop = level_index.slice_indexer(
key.start, key.stop, key.step, kind="loc"
)
step = start.step
if isinstance(start, slice) or isinstance(stop, slice):
# we have a slice for start and/or stop
# a partial date slicer on a DatetimeIndex generates a slice
# note that the stop ALREADY includes the stopped point (if
# it was a string sliced)
start = getattr(start, "start", start)
stop = getattr(stop, "stop", stop)
return convert_indexer(start, stop, step)
elif level > 0 or self.lexsort_depth == 0 or step is not None:
# need to have like semantics here to right
# searching as when we are using a slice
# so include the stop+1 (so we include stop)
return convert_indexer(start, stop + 1, step)
else:
# sorted, so can return slice object -> view
i = level_codes.searchsorted(start, side="left")
j = level_codes.searchsorted(stop, side="right")
return slice(i, j, step)
else:
code = self._get_loc_single_level_index(level_index, key)
if level > 0 or self.lexsort_depth == 0:
# Desired level is not sorted
locs = np.array(level_codes == code, dtype=bool, copy=False)
if not locs.any():
# The label is present in self.levels[level] but unused:
raise KeyError(key)
return locs
i = level_codes.searchsorted(code, side="left")
j = level_codes.searchsorted(code, side="right")
if i == j:
# The label is present in self.levels[level] but unused:
raise KeyError(key)
return slice(i, j)
def get_locs(self, seq):
"""
Get location for a sequence of labels.
Parameters
----------
seq : label, slice, list, mask or a sequence of such
You should use one of the above for each level.
If a level should not be used, set it to ``slice(None)``.
Returns
-------
numpy.ndarray
NumPy array of integers suitable for passing to iloc.
See Also
--------
MultiIndex.get_loc : Get location for a label or a tuple of labels.
MultiIndex.slice_locs : Get slice location given start label(s) and
end label(s).
Examples
--------
>>> mi = pd.MultiIndex.from_arrays([list('abb'), list('def')])
>>> mi.get_locs('b') # doctest: +SKIP
array([1, 2], dtype=int64)
>>> mi.get_locs([slice(None), ['e', 'f']]) # doctest: +SKIP
array([1, 2], dtype=int64)
>>> mi.get_locs([[True, False, True], slice('e', 'f')]) # doctest: +SKIP
array([2], dtype=int64)
"""
from pandas.core.indexes.numeric import Int64Index
# must be lexsorted to at least as many levels
true_slices = [i for (i, s) in enumerate(com.is_true_slices(seq)) if s]
if true_slices and true_slices[-1] >= self.lexsort_depth:
raise UnsortedIndexError(
"MultiIndex slicing requires the index to be lexsorted: slicing "
f"on levels {true_slices}, lexsort depth {self.lexsort_depth}"
)
# indexer
# this is the list of all values that we want to select
n = len(self)
indexer = None
def _convert_to_indexer(r) -> Int64Index:
# return an indexer
if isinstance(r, slice):
m = np.zeros(n, dtype=bool)
m[r] = True
r = m.nonzero()[0]
elif com.is_bool_indexer(r):
if len(r) != n:
raise ValueError(
"cannot index with a boolean indexer "
"that is not the same length as the "
"index"
)
r = r.nonzero()[0]
return Int64Index(r)
def _update_indexer(idxr, indexer=indexer):
if indexer is None:
indexer = Index(np.arange(n))
if idxr is None:
return indexer
return indexer & idxr
for i, k in enumerate(seq):
if com.is_bool_indexer(k):
# a boolean indexer, must be the same length!
k = np.asarray(k)
indexer = _update_indexer(_convert_to_indexer(k), indexer=indexer)
elif is_list_like(k):
# a collection of labels to include from this level (these
# are or'd)
indexers = None
for x in k:
try:
idxrs = _convert_to_indexer(
self._get_level_indexer(x, level=i, indexer=indexer)
)
indexers = idxrs if indexers is None else indexers | idxrs
except KeyError:
# ignore not founds
continue
if indexers is not None:
indexer = _update_indexer(indexers, indexer=indexer)
else:
# no matches we are done
return np.array([], dtype=np.int64)
elif com.is_null_slice(k):
# empty slice
indexer = _update_indexer(None, indexer=indexer)
elif isinstance(k, slice):
# a slice, include BOTH of the labels
indexer = _update_indexer(
_convert_to_indexer(
self._get_level_indexer(k, level=i, indexer=indexer)
),
indexer=indexer,
)
else:
# a single label
indexer = _update_indexer(
_convert_to_indexer(
self.get_loc_level(k, level=i, drop_level=False)[0]
),
indexer=indexer,
)
# empty indexer
if indexer is None:
return np.array([], dtype=np.int64)
assert isinstance(indexer, Int64Index), type(indexer)
indexer = self._reorder_indexer(seq, indexer)
return indexer._values
def _reorder_indexer(
self,
seq: Tuple[Union[Scalar, Iterable, AnyArrayLike], ...],
indexer: Int64Index,
) -> Int64Index:
"""
Reorder an indexer of a MultiIndex (self) so that the label are in the
same order as given in seq
Parameters
----------
seq : label/slice/list/mask or a sequence of such
indexer: an Int64Index indexer of self
Returns
-------
indexer : a sorted Int64Index indexer of self ordered as seq
"""
# If the index is lexsorted and the list_like label in seq are sorted
# then we do not need to sort
if self.is_lexsorted():
need_sort = False
for i, k in enumerate(seq):
if is_list_like(k):
if not need_sort:
k_codes = self.levels[i].get_indexer(k)
k_codes = k_codes[k_codes >= 0] # Filter absent keys
# True if the given codes are not ordered
need_sort = (k_codes[:-1] > k_codes[1:]).any()
# Bail out if both index and seq are sorted
if not need_sort:
return indexer
n = len(self)
keys: Tuple[np.ndarray, ...] = tuple()
# For each level of the sequence in seq, map the level codes with the
# order they appears in a list-like sequence
# This mapping is then use to reorder the indexer
for i, k in enumerate(seq):
if com.is_bool_indexer(k):
new_order = np.arange(n)[indexer]
elif is_list_like(k):
# Generate a map with all level codes as sorted initially
key_order_map = np.ones(len(self.levels[i]), dtype=np.uint64) * len(
self.levels[i]
)
# Set order as given in the indexer list
level_indexer = self.levels[i].get_indexer(k)
level_indexer = level_indexer[level_indexer >= 0] # Filter absent keys
key_order_map[level_indexer] = np.arange(len(level_indexer))
new_order = key_order_map[self.codes[i][indexer]]
else:
# For all other case, use the same order as the level
new_order = np.arange(n)[indexer]
keys = (new_order,) + keys
# Find the reordering using lexsort on the keys mapping
ind = np.lexsort(keys)
return indexer[ind]
def truncate(self, before=None, after=None):
"""
Slice index between two labels / tuples, return new MultiIndex
Parameters
----------
before : label or tuple, can be partial. Default None
None defaults to start
after : label or tuple, can be partial. Default None
None defaults to end
Returns
-------
truncated : MultiIndex
"""
if after and before and after < before:
raise ValueError("after < before")
i, j = self.levels[0].slice_locs(before, after)
left, right = self.slice_locs(before, after)
new_levels = list(self.levels)
new_levels[0] = new_levels[0][i:j]
new_codes = [level_codes[left:right] for level_codes in self.codes]
new_codes[0] = new_codes[0] - i
return MultiIndex(levels=new_levels, codes=new_codes, verify_integrity=False)
def equals(self, other) -> bool:
"""
Determines if two MultiIndex objects have the same labeling information
(the levels themselves do not necessarily have to be the same)
See Also
--------
equal_levels
"""
if self.is_(other):
return True
if not isinstance(other, Index):
return False
if not isinstance(other, MultiIndex):
# d-level MultiIndex can equal d-tuple Index
if not is_object_dtype(other.dtype):
# other cannot contain tuples, so cannot match self
return False
return array_equivalent(self._values, other._values)
if self.nlevels != other.nlevels:
return False
if len(self) != len(other):
return False
for i in range(self.nlevels):
self_codes = self.codes[i]
self_codes = self_codes[self_codes != -1]
self_values = algos.take_nd(
np.asarray(self.levels[i]._values), self_codes, allow_fill=False
)
other_codes = other.codes[i]
other_codes = other_codes[other_codes != -1]
other_values = algos.take_nd(
np.asarray(other.levels[i]._values), other_codes, allow_fill=False
)
# since we use NaT both datetime64 and timedelta64
# we can have a situation where a level is typed say
# timedelta64 in self (IOW it has other values than NaT)
# but types datetime64 in other (where its all NaT)
# but these are equivalent
if len(self_values) == 0 and len(other_values) == 0:
continue
if not array_equivalent(self_values, other_values):
return False
return True
def equal_levels(self, other) -> bool:
"""
Return True if the levels of both MultiIndex objects are the same
"""
if self.nlevels != other.nlevels:
return False
for i in range(self.nlevels):
if not self.levels[i].equals(other.levels[i]):
return False
return True
# --------------------------------------------------------------------
# Set Methods
def union(self, other, sort=None):
"""
Form the union of two MultiIndex objects
Parameters
----------
other : MultiIndex or array / Index of tuples
sort : False or None, default None
Whether to sort the resulting Index.
* None : Sort the result, except when
1. `self` and `other` are equal.
2. `self` has length 0.
3. Some values in `self` or `other` cannot be compared.
A RuntimeWarning is issued in this case.
* False : do not sort the result.
.. versionadded:: 0.24.0
.. versionchanged:: 0.24.1
Changed the default value from ``True`` to ``None``
(without change in behaviour).
Returns
-------
Index
>>> index.union(index2)
"""
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
other, result_names = self._convert_can_do_setop(other)
if len(other) == 0 or self.equals(other):
return self
# TODO: Index.union returns other when `len(self)` is 0.
uniq_tuples = lib.fast_unique_multiple(
[self._values, other._ndarray_values], sort=sort
)
return MultiIndex.from_arrays(
zip(*uniq_tuples), sortorder=0, names=result_names
)
def intersection(self, other, sort=False):
"""
Form the intersection of two MultiIndex objects.
Parameters
----------
other : MultiIndex or array / Index of tuples
sort : False or None, default False
Sort the resulting MultiIndex if possible
.. versionadded:: 0.24.0
.. versionchanged:: 0.24.1
Changed the default from ``True`` to ``False``, to match
behaviour from before 0.24.0
Returns
-------
Index
"""
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
other, result_names = self._convert_can_do_setop(other)
if self.equals(other):
return self
lvals = self._values
rvals = other._ndarray_values
uniq_tuples = None # flag whether _inner_indexer was succesful
if self.is_monotonic and other.is_monotonic:
try:
uniq_tuples = self._inner_indexer(lvals, rvals)[0]
sort = False # uniq_tuples is already sorted
except TypeError:
pass
if uniq_tuples is None:
other_uniq = set(rvals)
seen = set()
uniq_tuples = [
x for x in lvals if x in other_uniq and not (x in seen or seen.add(x))
]
if sort is None:
uniq_tuples = sorted(uniq_tuples)
if len(uniq_tuples) == 0:
return MultiIndex(
levels=self.levels,
codes=[[]] * self.nlevels,
names=result_names,
verify_integrity=False,
)
else:
return MultiIndex.from_arrays(
zip(*uniq_tuples), sortorder=0, names=result_names
)
def difference(self, other, sort=None):
"""
Compute set difference of two MultiIndex objects
Parameters
----------
other : MultiIndex
sort : False or None, default None
Sort the resulting MultiIndex if possible
.. versionadded:: 0.24.0
.. versionchanged:: 0.24.1
Changed the default value from ``True`` to ``None``
(without change in behaviour).
Returns
-------
diff : MultiIndex
"""
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
other, result_names = self._convert_can_do_setop(other)
if len(other) == 0:
return self
if self.equals(other):
return MultiIndex(
levels=self.levels,
codes=[[]] * self.nlevels,
names=result_names,
verify_integrity=False,
)
this = self._get_unique_index()
indexer = this.get_indexer(other)
indexer = indexer.take((indexer != -1).nonzero()[0])
label_diff = np.setdiff1d(np.arange(this.size), indexer, assume_unique=True)
difference = this._values.take(label_diff)
if sort is None:
difference = sorted(difference)
if len(difference) == 0:
return MultiIndex(
levels=[[]] * self.nlevels,
codes=[[]] * self.nlevels,
names=result_names,
verify_integrity=False,
)
else:
return MultiIndex.from_tuples(difference, sortorder=0, names=result_names)
def _convert_can_do_setop(self, other):
result_names = self.names
if not isinstance(other, Index):
if len(other) == 0:
other = MultiIndex(
levels=[[]] * self.nlevels,
codes=[[]] * self.nlevels,
verify_integrity=False,
)
else:
msg = "other must be a MultiIndex or a list of tuples"
try:
other = MultiIndex.from_tuples(other)
except TypeError as err:
raise TypeError(msg) from err
else:
result_names = self.names if self.names == other.names else None
return other, result_names
# --------------------------------------------------------------------
@Appender(Index.astype.__doc__)
def astype(self, dtype, copy=True):
dtype = pandas_dtype(dtype)
if is_categorical_dtype(dtype):
msg = "> 1 ndim Categorical are not supported at this time"
raise NotImplementedError(msg)
elif not is_object_dtype(dtype):
raise TypeError(
f"Setting {type(self)} dtype to anything other "
"than object is not supported"
)
elif copy is True:
return self._shallow_copy()
return self
def insert(self, loc: int, item):
"""
Make new MultiIndex inserting new item at location
Parameters
----------
loc : int
item : tuple
Must be same length as number of levels in the MultiIndex
Returns
-------
new_index : Index
"""
# Pad the key with empty strings if lower levels of the key
# aren't specified:
if not isinstance(item, tuple):
item = (item,) + ("",) * (self.nlevels - 1)
elif len(item) != self.nlevels:
raise ValueError("Item must have length equal to number of levels.")
new_levels = []
new_codes = []
for k, level, level_codes in zip(item, self.levels, self.codes):
if k not in level:
# have to insert into level
# must insert at end otherwise you have to recompute all the
# other codes
lev_loc = len(level)
level = level.insert(lev_loc, k)
else:
lev_loc = level.get_loc(k)
new_levels.append(level)
new_codes.append(np.insert(ensure_int64(level_codes), loc, lev_loc))
return MultiIndex(
levels=new_levels, codes=new_codes, names=self.names, verify_integrity=False
)
def delete(self, loc):
"""
Make new index with passed location deleted
Returns
-------
new_index : MultiIndex
"""
new_codes = [np.delete(level_codes, loc) for level_codes in self.codes]
return MultiIndex(
levels=self.levels,
codes=new_codes,
names=self.names,
verify_integrity=False,
)
def _wrap_joined_index(self, joined, other):
names = self.names if self.names == other.names else None
return MultiIndex.from_tuples(joined, names=names)
@Appender(Index.isin.__doc__)
def isin(self, values, level=None):
if level is None:
values = MultiIndex.from_tuples(values, names=self.names)._values
return algos.isin(self._values, values)
else:
num = self._get_level_number(level)
levs = self.get_level_values(num)
if levs.size == 0:
return np.zeros(len(levs), dtype=np.bool_)
return levs.isin(values)
MultiIndex._add_numeric_methods_disabled()
MultiIndex._add_numeric_methods_add_sub_disabled()
MultiIndex._add_logical_methods_disabled()
def _sparsify(label_list, start: int = 0, sentinel=""):
pivoted = list(zip(*label_list))
k = len(label_list)
result = pivoted[: start + 1]
prev = pivoted[start]
for cur in pivoted[start + 1 :]:
sparse_cur = []
for i, (p, t) in enumerate(zip(prev, cur)):
if i == k - 1:
sparse_cur.append(t)
result.append(sparse_cur)
break
if p == t:
sparse_cur.append(sentinel)
else:
sparse_cur.extend(cur[i:])
result.append(sparse_cur)
break
prev = cur
return list(zip(*result))
def _get_na_rep(dtype) -> str:
return {np.datetime64: "NaT", np.timedelta64: "NaT"}.get(dtype, "NaN")
def maybe_droplevels(index, key):
"""
Attempt to drop level or levels from the given index.
Parameters
----------
index: Index
key : scalar or tuple
Returns
-------
Index
"""
# drop levels
original_index = index
if isinstance(key, tuple):
for _ in key:
try:
index = index.droplevel(0)
except ValueError:
# we have dropped too much, so back out
return original_index
else:
try:
index = index.droplevel(0)
except ValueError:
pass
return index
def _coerce_indexer_frozen(array_like, categories, copy: bool = False) -> np.ndarray:
"""
Coerce the array_like indexer to the smallest integer dtype that can encode all
of the given categories.
Parameters
----------
array_like : array-like
categories : array-like
copy : bool
Returns
-------
np.ndarray
Non-writeable.
"""
array_like = coerce_indexer_dtype(array_like, categories)
if copy:
array_like = array_like.copy()
array_like.flags.writeable = False
return array_like
| BugsInPy/BugsInPy/temp/projects/pandas/bug-46-fixed/pandas/pandas/core/indexes/multi.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-46-buggy/pandas/pandas/core/indexes/multi.py |
pandas-bug-103 | """
Define the SeriesGroupBy and DataFrameGroupBy
classes that hold the groupby interfaces (and some implementations).
These are user facing as the result of the ``df.groupby(...)`` operations,
which here returns a DataFrameGroupBy object.
"""
from collections import OrderedDict, abc, defaultdict, namedtuple
import copy
from functools import partial
from textwrap import dedent
import typing
from typing import (
TYPE_CHECKING,
Any,
Callable,
FrozenSet,
Iterable,
List,
Mapping,
Sequence,
Tuple,
Type,
Union,
cast,
)
import numpy as np
from pandas._libs import Timestamp, lib
from pandas._typing import FrameOrSeries
from pandas.util._decorators import Appender, Substitution
from pandas.core.dtypes.cast import (
maybe_convert_objects,
maybe_downcast_numeric,
maybe_downcast_to_dtype,
)
from pandas.core.dtypes.common import (
ensure_int64,
ensure_platform_int,
is_bool,
is_dict_like,
is_integer_dtype,
is_interval_dtype,
is_list_like,
is_numeric_dtype,
is_object_dtype,
is_scalar,
needs_i8_conversion,
)
from pandas.core.dtypes.missing import _isna_ndarraylike, isna, notna
import pandas.core.algorithms as algorithms
from pandas.core.base import DataError, SpecificationError
import pandas.core.common as com
from pandas.core.construction import create_series_with_explicit_dtype
from pandas.core.frame import DataFrame
from pandas.core.generic import ABCDataFrame, ABCSeries, NDFrame, _shared_docs
from pandas.core.groupby import base
from pandas.core.groupby.groupby import (
GroupBy,
_apply_docs,
_transform_template,
get_groupby,
)
from pandas.core.indexes.api import Index, MultiIndex, all_indexes_same
import pandas.core.indexes.base as ibase
from pandas.core.internals import BlockManager, make_block
from pandas.core.series import Series
from pandas.plotting import boxplot_frame_groupby
if TYPE_CHECKING:
from pandas.core.internals import Block
NamedAgg = namedtuple("NamedAgg", ["column", "aggfunc"])
# TODO(typing) the return value on this callable should be any *scalar*.
AggScalar = Union[str, Callable[..., Any]]
# TODO: validate types on ScalarResult and move to _typing
# Blocked from using by https://github.com/python/mypy/issues/1484
# See note at _mangle_lambda_list
ScalarResult = typing.TypeVar("ScalarResult")
def generate_property(name: str, klass: Type[FrameOrSeries]):
"""
Create a property for a GroupBy subclass to dispatch to DataFrame/Series.
Parameters
----------
name : str
klass : {DataFrame, Series}
Returns
-------
property
"""
def prop(self):
return self._make_wrapper(name)
parent_method = getattr(klass, name)
prop.__doc__ = parent_method.__doc__ or ""
prop.__name__ = name
return property(prop)
def pin_whitelisted_properties(klass: Type[FrameOrSeries], whitelist: FrozenSet[str]):
"""
Create GroupBy member defs for DataFrame/Series names in a whitelist.
Parameters
----------
klass : DataFrame or Series class
class where members are defined.
whitelist : frozenset[str]
Set of names of klass methods to be constructed
Returns
-------
class decorator
Notes
-----
Since we don't want to override methods explicitly defined in the
base class, any such name is skipped.
"""
def pinner(cls):
for name in whitelist:
if hasattr(cls, name):
# don't override anything that was explicitly defined
# in the base class
continue
prop = generate_property(name, klass)
setattr(cls, name, prop)
return cls
return pinner
@pin_whitelisted_properties(Series, base.series_apply_whitelist)
class SeriesGroupBy(GroupBy):
_apply_whitelist = base.series_apply_whitelist
def _iterate_slices(self) -> Iterable[Series]:
yield self._selected_obj
@property
def _selection_name(self):
"""
since we are a series, we by definition only have
a single name, but may be the result of a selection or
the name of our object
"""
if self._selection is None:
return self.obj.name
else:
return self._selection
_agg_see_also_doc = dedent(
"""
See Also
--------
pandas.Series.groupby.apply
pandas.Series.groupby.transform
pandas.Series.aggregate
"""
)
_agg_examples_doc = dedent(
"""
Examples
--------
>>> s = pd.Series([1, 2, 3, 4])
>>> s
0 1
1 2
2 3
3 4
dtype: int64
>>> s.groupby([1, 1, 2, 2]).min()
1 1
2 3
dtype: int64
>>> s.groupby([1, 1, 2, 2]).agg('min')
1 1
2 3
dtype: int64
>>> s.groupby([1, 1, 2, 2]).agg(['min', 'max'])
min max
1 1 2
2 3 4
The output column names can be controlled by passing
the desired column names and aggregations as keyword arguments.
>>> s.groupby([1, 1, 2, 2]).agg(
... minimum='min',
... maximum='max',
... )
minimum maximum
1 1 2
2 3 4
"""
)
@Appender(
_apply_docs["template"].format(
input="series", examples=_apply_docs["series_examples"]
)
)
def apply(self, func, *args, **kwargs):
return super().apply(func, *args, **kwargs)
@Substitution(
see_also=_agg_see_also_doc,
examples=_agg_examples_doc,
versionadded="",
klass="Series",
axis="",
)
@Appender(_shared_docs["aggregate"])
def aggregate(self, func=None, *args, **kwargs):
relabeling = func is None
columns = None
no_arg_message = "Must provide 'func' or named aggregation **kwargs."
if relabeling:
columns = list(kwargs)
func = [kwargs[col] for col in columns]
kwargs = {}
if not columns:
raise TypeError(no_arg_message)
if isinstance(func, str):
return getattr(self, func)(*args, **kwargs)
elif isinstance(func, abc.Iterable):
# Catch instances of lists / tuples
# but not the class list / tuple itself.
func = _maybe_mangle_lambdas(func)
ret = self._aggregate_multiple_funcs(func)
if relabeling:
ret.columns = columns
else:
cyfunc = self._get_cython_func(func)
if cyfunc and not args and not kwargs:
return getattr(self, cyfunc)()
if self.grouper.nkeys > 1:
return self._python_agg_general(func, *args, **kwargs)
try:
return self._python_agg_general(func, *args, **kwargs)
except (ValueError, KeyError):
# TODO: KeyError is raised in _python_agg_general,
# see see test_groupby.test_basic
result = self._aggregate_named(func, *args, **kwargs)
index = Index(sorted(result), name=self.grouper.names[0])
ret = create_series_with_explicit_dtype(
result, index=index, dtype_if_empty=object
)
if not self.as_index: # pragma: no cover
print("Warning, ignoring as_index=True")
if isinstance(ret, dict):
from pandas import concat
ret = concat(ret, axis=1)
return ret
agg = aggregate
def _aggregate_multiple_funcs(self, arg):
if isinstance(arg, dict):
# show the deprecation, but only if we
# have not shown a higher level one
# GH 15931
if isinstance(self._selected_obj, Series):
raise SpecificationError("nested renamer is not supported")
columns = list(arg.keys())
arg = arg.items()
elif any(isinstance(x, (tuple, list)) for x in arg):
arg = [(x, x) if not isinstance(x, (tuple, list)) else x for x in arg]
# indicated column order
columns = next(zip(*arg))
else:
# list of functions / function names
columns = []
for f in arg:
columns.append(com.get_callable_name(f) or f)
arg = zip(columns, arg)
results = OrderedDict()
for name, func in arg:
obj = self
# reset the cache so that we
# only include the named selection
if name in self._selected_obj:
obj = copy.copy(obj)
obj._reset_cache()
obj._selection = name
results[name] = obj.aggregate(func)
if any(isinstance(x, DataFrame) for x in results.values()):
# let higher level handle
return results
return DataFrame(results, columns=columns)
def _wrap_series_output(
self, output: Mapping[base.OutputKey, Union[Series, np.ndarray]], index: Index,
) -> Union[Series, DataFrame]:
"""
Wraps the output of a SeriesGroupBy operation into the expected result.
Parameters
----------
output : Mapping[base.OutputKey, Union[Series, np.ndarray]]
Data to wrap.
index : pd.Index
Index to apply to the output.
Returns
-------
Series or DataFrame
Notes
-----
In the vast majority of cases output and columns will only contain one
element. The exception is operations that expand dimensions, like ohlc.
"""
indexed_output = {key.position: val for key, val in output.items()}
columns = Index(key.label for key in output)
result: Union[Series, DataFrame]
if len(output) > 1:
result = DataFrame(indexed_output, index=index)
result.columns = columns
else:
result = Series(indexed_output[0], index=index, name=columns[0])
return result
def _wrap_aggregated_output(
self, output: Mapping[base.OutputKey, Union[Series, np.ndarray]]
) -> Union[Series, DataFrame]:
"""
Wraps the output of a SeriesGroupBy aggregation into the expected result.
Parameters
----------
output : Mapping[base.OutputKey, Union[Series, np.ndarray]]
Data to wrap.
Returns
-------
Series or DataFrame
Notes
-----
In the vast majority of cases output will only contain one element.
The exception is operations that expand dimensions, like ohlc.
"""
result = self._wrap_series_output(
output=output, index=self.grouper.result_index
)
return self._reindex_output(result)._convert(datetime=True)
def _wrap_transformed_output(
self, output: Mapping[base.OutputKey, Union[Series, np.ndarray]]
) -> Series:
"""
Wraps the output of a SeriesGroupBy aggregation into the expected result.
Parameters
----------
output : dict[base.OutputKey, Union[Series, np.ndarray]]
Dict with a sole key of 0 and a value of the result values.
Returns
-------
Series
Notes
-----
output should always contain one element. It is specified as a dict
for consistency with DataFrame methods and _wrap_aggregated_output.
"""
assert len(output) == 1
result = self._wrap_series_output(output=output, index=self.obj.index)
# No transformations increase the ndim of the result
assert isinstance(result, Series)
return result
def _wrap_applied_output(self, keys, values, not_indexed_same=False):
if len(keys) == 0:
# GH #6265
return Series([], name=self._selection_name, index=keys, dtype=np.float64)
def _get_index() -> Index:
if self.grouper.nkeys > 1:
index = MultiIndex.from_tuples(keys, names=self.grouper.names)
else:
index = Index(keys, name=self.grouper.names[0])
return index
if isinstance(values[0], dict):
# GH #823 #24880
index = _get_index()
result = self._reindex_output(DataFrame(values, index=index))
# if self.observed is False,
# keep all-NaN rows created while re-indexing
result = result.stack(dropna=self.observed)
result.name = self._selection_name
return result
if isinstance(values[0], Series):
return self._concat_objects(keys, values, not_indexed_same=not_indexed_same)
elif isinstance(values[0], DataFrame):
# possible that Series -> DataFrame by applied function
return self._concat_objects(keys, values, not_indexed_same=not_indexed_same)
else:
# GH #6265 #24880
result = Series(data=values, index=_get_index(), name=self._selection_name)
return self._reindex_output(result)
def _aggregate_named(self, func, *args, **kwargs):
result = OrderedDict()
for name, group in self:
group.name = name
output = func(group, *args, **kwargs)
if isinstance(output, (Series, Index, np.ndarray)):
raise ValueError("Must produce aggregated value")
result[name] = output
return result
@Substitution(klass="Series", selected="A.")
@Appender(_transform_template)
def transform(self, func, *args, **kwargs):
func = self._get_cython_func(func) or func
if not isinstance(func, str):
return self._transform_general(func, *args, **kwargs)
elif func not in base.transform_kernel_whitelist:
msg = f"'{func}' is not a valid function name for transform(name)"
raise ValueError(msg)
elif func in base.cythonized_kernels:
# cythonized transform or canned "agg+broadcast"
return getattr(self, func)(*args, **kwargs)
# If func is a reduction, we need to broadcast the
# result to the whole group. Compute func result
# and deal with possible broadcasting below.
result = getattr(self, func)(*args, **kwargs)
return self._transform_fast(result, func)
def _transform_general(self, func, *args, **kwargs):
"""
Transform with a non-str `func`.
"""
klass = type(self._selected_obj)
results = []
for name, group in self:
object.__setattr__(group, "name", name)
res = func(group, *args, **kwargs)
if isinstance(res, (ABCDataFrame, ABCSeries)):
res = res._values
indexer = self._get_index(name)
ser = klass(res, indexer)
results.append(ser)
# check for empty "results" to avoid concat ValueError
if results:
from pandas.core.reshape.concat import concat
result = concat(results).sort_index()
else:
result = Series(dtype=np.float64)
# we will only try to coerce the result type if
# we have a numeric dtype, as these are *always* user-defined funcs
# the cython take a different path (and casting)
dtype = self._selected_obj.dtype
if is_numeric_dtype(dtype):
result = maybe_downcast_to_dtype(result, dtype)
result.name = self._selected_obj.name
result.index = self._selected_obj.index
return result
def _transform_fast(self, result, func_nm: str) -> Series:
"""
fast version of transform, only applicable to
builtin/cythonizable functions
"""
ids, _, ngroup = self.grouper.group_info
cast = self._transform_should_cast(func_nm)
out = algorithms.take_1d(result._values, ids)
if cast:
out = self._try_cast(out, self.obj)
return Series(out, index=self.obj.index, name=self.obj.name)
def filter(self, func, dropna=True, *args, **kwargs):
"""
Return a copy of a Series excluding elements from groups that
do not satisfy the boolean criterion specified by func.
Parameters
----------
func : function
To apply to each group. Should return True or False.
dropna : Drop groups that do not pass the filter. True by default;
if False, groups that evaluate False are filled with NaNs.
Examples
--------
>>> df = pd.DataFrame({'A' : ['foo', 'bar', 'foo', 'bar',
... 'foo', 'bar'],
... 'B' : [1, 2, 3, 4, 5, 6],
... 'C' : [2.0, 5., 8., 1., 2., 9.]})
>>> grouped = df.groupby('A')
>>> df.groupby('A').B.filter(lambda x: x.mean() > 3.)
1 2
3 4
5 6
Name: B, dtype: int64
Returns
-------
filtered : Series
"""
if isinstance(func, str):
wrapper = lambda x: getattr(x, func)(*args, **kwargs)
else:
wrapper = lambda x: func(x, *args, **kwargs)
# Interpret np.nan as False.
def true_and_notna(x, *args, **kwargs) -> bool:
b = wrapper(x, *args, **kwargs)
return b and notna(b)
try:
indices = [
self._get_index(name) for name, group in self if true_and_notna(group)
]
except (ValueError, TypeError):
raise TypeError("the filter must return a boolean result")
filtered = self._apply_filter(indices, dropna)
return filtered
def nunique(self, dropna: bool = True) -> Series:
"""
Return number of unique elements in the group.
Returns
-------
Series
Number of unique values within each group.
"""
ids, _, _ = self.grouper.group_info
val = self.obj._internal_get_values()
# GH 27951
# temporary fix while we wait for NumPy bug 12629 to be fixed
val[isna(val)] = np.datetime64("NaT")
try:
sorter = np.lexsort((val, ids))
except TypeError: # catches object dtypes
msg = f"val.dtype must be object, got {val.dtype}"
assert val.dtype == object, msg
val, _ = algorithms.factorize(val, sort=False)
sorter = np.lexsort((val, ids))
_isna = lambda a: a == -1
else:
_isna = isna
ids, val = ids[sorter], val[sorter]
# group boundaries are where group ids change
# unique observations are where sorted values change
idx = np.r_[0, 1 + np.nonzero(ids[1:] != ids[:-1])[0]]
inc = np.r_[1, val[1:] != val[:-1]]
# 1st item of each group is a new unique observation
mask = _isna(val)
if dropna:
inc[idx] = 1
inc[mask] = 0
else:
inc[mask & np.r_[False, mask[:-1]]] = 0
inc[idx] = 1
out = np.add.reduceat(inc, idx).astype("int64", copy=False)
if len(ids):
# NaN/NaT group exists if the head of ids is -1,
# so remove it from res and exclude its index from idx
if ids[0] == -1:
res = out[1:]
idx = idx[np.flatnonzero(idx)]
else:
res = out
else:
res = out[1:]
ri = self.grouper.result_index
# we might have duplications among the bins
if len(res) != len(ri):
res, out = np.zeros(len(ri), dtype=out.dtype), res
res[ids[idx]] = out
result = Series(res, index=ri, name=self._selection_name)
return self._reindex_output(result, fill_value=0)
@Appender(Series.describe.__doc__)
def describe(self, **kwargs):
result = self.apply(lambda x: x.describe(**kwargs))
if self.axis == 1:
return result.T
return result.unstack()
def value_counts(
self, normalize=False, sort=True, ascending=False, bins=None, dropna=True
):
from pandas.core.reshape.tile import cut
from pandas.core.reshape.merge import _get_join_indexers
if bins is not None and not np.iterable(bins):
# scalar bins cannot be done at top level
# in a backward compatible way
return self.apply(
Series.value_counts,
normalize=normalize,
sort=sort,
ascending=ascending,
bins=bins,
)
ids, _, _ = self.grouper.group_info
val = self.obj._internal_get_values()
# groupby removes null keys from groupings
mask = ids != -1
ids, val = ids[mask], val[mask]
if bins is None:
lab, lev = algorithms.factorize(val, sort=True)
llab = lambda lab, inc: lab[inc]
else:
# lab is a Categorical with categories an IntervalIndex
lab = cut(Series(val), bins, include_lowest=True)
lev = lab.cat.categories
lab = lev.take(lab.cat.codes)
llab = lambda lab, inc: lab[inc]._multiindex.codes[-1]
if is_interval_dtype(lab):
# TODO: should we do this inside II?
sorter = np.lexsort((lab.left, lab.right, ids))
else:
sorter = np.lexsort((lab, ids))
ids, lab = ids[sorter], lab[sorter]
# group boundaries are where group ids change
idx = np.r_[0, 1 + np.nonzero(ids[1:] != ids[:-1])[0]]
# new values are where sorted labels change
lchanges = llab(lab, slice(1, None)) != llab(lab, slice(None, -1))
inc = np.r_[True, lchanges]
inc[idx] = True # group boundaries are also new values
out = np.diff(np.nonzero(np.r_[inc, True])[0]) # value counts
# num. of times each group should be repeated
rep = partial(np.repeat, repeats=np.add.reduceat(inc, idx))
# multi-index components
codes = self.grouper.reconstructed_codes
codes = [rep(level_codes) for level_codes in codes] + [llab(lab, inc)]
levels = [ping.group_index for ping in self.grouper.groupings] + [lev]
names = self.grouper.names + [self._selection_name]
if dropna:
mask = codes[-1] != -1
if mask.all():
dropna = False
else:
out, codes = out[mask], [level_codes[mask] for level_codes in codes]
if normalize:
out = out.astype("float")
d = np.diff(np.r_[idx, len(ids)])
if dropna:
m = ids[lab == -1]
np.add.at(d, m, -1)
acc = rep(d)[mask]
else:
acc = rep(d)
out /= acc
if sort and bins is None:
cat = ids[inc][mask] if dropna else ids[inc]
sorter = np.lexsort((out if ascending else -out, cat))
out, codes[-1] = out[sorter], codes[-1][sorter]
if bins is None:
mi = MultiIndex(
levels=levels, codes=codes, names=names, verify_integrity=False
)
if is_integer_dtype(out):
out = ensure_int64(out)
return Series(out, index=mi, name=self._selection_name)
# for compat. with libgroupby.value_counts need to ensure every
# bin is present at every index level, null filled with zeros
diff = np.zeros(len(out), dtype="bool")
for level_codes in codes[:-1]:
diff |= np.r_[True, level_codes[1:] != level_codes[:-1]]
ncat, nbin = diff.sum(), len(levels[-1])
left = [np.repeat(np.arange(ncat), nbin), np.tile(np.arange(nbin), ncat)]
right = [diff.cumsum() - 1, codes[-1]]
_, idx = _get_join_indexers(left, right, sort=False, how="left")
out = np.where(idx != -1, out[idx], 0)
if sort:
sorter = np.lexsort((out if ascending else -out, left[0]))
out, left[-1] = out[sorter], left[-1][sorter]
# build the multi-index w/ full levels
def build_codes(lev_codes: np.ndarray) -> np.ndarray:
return np.repeat(lev_codes[diff], nbin)
codes = [build_codes(lev_codes) for lev_codes in codes[:-1]]
codes.append(left[-1])
mi = MultiIndex(levels=levels, codes=codes, names=names, verify_integrity=False)
if is_integer_dtype(out):
out = ensure_int64(out)
return Series(out, index=mi, name=self._selection_name)
def count(self) -> Series:
"""
Compute count of group, excluding missing values.
Returns
-------
Series
Count of values within each group.
"""
ids, _, ngroups = self.grouper.group_info
val = self.obj._internal_get_values()
mask = (ids != -1) & ~isna(val)
ids = ensure_platform_int(ids)
minlength = ngroups or 0
out = np.bincount(ids[mask], minlength=minlength)
result = Series(
out,
index=self.grouper.result_index,
name=self._selection_name,
dtype="int64",
)
return self._reindex_output(result, fill_value=0)
def _apply_to_column_groupbys(self, func):
""" return a pass thru """
return func(self)
def pct_change(self, periods=1, fill_method="pad", limit=None, freq=None):
"""Calculate pct_change of each value to previous entry in group"""
# TODO: Remove this conditional when #23918 is fixed
if freq:
return self.apply(
lambda x: x.pct_change(
periods=periods, fill_method=fill_method, limit=limit, freq=freq
)
)
filled = getattr(self, fill_method)(limit=limit)
fill_grp = filled.groupby(self.grouper.codes)
shifted = fill_grp.shift(periods=periods, freq=freq)
return (filled / shifted) - 1
@pin_whitelisted_properties(DataFrame, base.dataframe_apply_whitelist)
class DataFrameGroupBy(GroupBy):
_apply_whitelist = base.dataframe_apply_whitelist
_agg_see_also_doc = dedent(
"""
See Also
--------
pandas.DataFrame.groupby.apply
pandas.DataFrame.groupby.transform
pandas.DataFrame.aggregate
"""
)
_agg_examples_doc = dedent(
"""
Examples
--------
>>> df = pd.DataFrame({'A': [1, 1, 2, 2],
... 'B': [1, 2, 3, 4],
... 'C': np.random.randn(4)})
>>> df
A B C
0 1 1 0.362838
1 1 2 0.227877
2 2 3 1.267767
3 2 4 -0.562860
The aggregation is for each column.
>>> df.groupby('A').agg('min')
B C
A
1 1 0.227877
2 3 -0.562860
Multiple aggregations
>>> df.groupby('A').agg(['min', 'max'])
B C
min max min max
A
1 1 2 0.227877 0.362838
2 3 4 -0.562860 1.267767
Select a column for aggregation
>>> df.groupby('A').B.agg(['min', 'max'])
min max
A
1 1 2
2 3 4
Different aggregations per column
>>> df.groupby('A').agg({'B': ['min', 'max'], 'C': 'sum'})
B C
min max sum
A
1 1 2 0.590716
2 3 4 0.704907
To control the output names with different aggregations per column,
pandas supports "named aggregation"
>>> df.groupby("A").agg(
... b_min=pd.NamedAgg(column="B", aggfunc="min"),
... c_sum=pd.NamedAgg(column="C", aggfunc="sum"))
b_min c_sum
A
1 1 -1.956929
2 3 -0.322183
- The keywords are the *output* column names
- The values are tuples whose first element is the column to select
and the second element is the aggregation to apply to that column.
Pandas provides the ``pandas.NamedAgg`` namedtuple with the fields
``['column', 'aggfunc']`` to make it clearer what the arguments are.
As usual, the aggregation can be a callable or a string alias.
See :ref:`groupby.aggregate.named` for more.
"""
)
@Substitution(
see_also=_agg_see_also_doc,
examples=_agg_examples_doc,
versionadded="",
klass="DataFrame",
axis="",
)
@Appender(_shared_docs["aggregate"])
def aggregate(self, func=None, *args, **kwargs):
relabeling = func is None and _is_multi_agg_with_relabel(**kwargs)
if relabeling:
func, columns, order = _normalize_keyword_aggregation(kwargs)
kwargs = {}
elif isinstance(func, list) and len(func) > len(set(func)):
# GH 28426 will raise error if duplicated function names are used and
# there is no reassigned name
raise SpecificationError(
"Function names must be unique if there is no new column "
"names assigned"
)
elif func is None:
# nicer error message
raise TypeError("Must provide 'func' or tuples of '(column, aggfunc).")
func = _maybe_mangle_lambdas(func)
result, how = self._aggregate(func, *args, **kwargs)
if how is None:
return result
if result is None:
# grouper specific aggregations
if self.grouper.nkeys > 1:
return self._python_agg_general(func, *args, **kwargs)
elif args or kwargs:
result = self._aggregate_frame(func, *args, **kwargs)
elif self.axis == 1:
# _aggregate_multiple_funcs does not allow self.axis == 1
result = self._aggregate_frame(func)
else:
# try to treat as if we are passing a list
try:
result = self._aggregate_multiple_funcs([func], _axis=self.axis)
except ValueError as err:
if "no results" not in str(err):
# raised directly by _aggregate_multiple_funcs
raise
result = self._aggregate_frame(func)
else:
result.columns = Index(
result.columns.levels[0], name=self._selected_obj.columns.name
)
if not self.as_index:
self._insert_inaxis_grouper_inplace(result)
result.index = np.arange(len(result))
if relabeling:
# used reordered index of columns
result = result.iloc[:, order]
result.columns = columns
return result._convert(datetime=True)
agg = aggregate
def _iterate_slices(self) -> Iterable[Series]:
obj = self._selected_obj
if self.axis == 1:
obj = obj.T
if isinstance(obj, Series) and obj.name not in self.exclusions:
# Occurs when doing DataFrameGroupBy(...)["X"]
yield obj
else:
for label, values in obj.items():
if label in self.exclusions:
continue
yield values
def _cython_agg_general(
self, how: str, alt=None, numeric_only: bool = True, min_count: int = -1
) -> DataFrame:
agg_blocks, agg_items = self._cython_agg_blocks(
how, alt=alt, numeric_only=numeric_only, min_count=min_count
)
return self._wrap_agged_blocks(agg_blocks, items=agg_items)
def _cython_agg_blocks(
self, how: str, alt=None, numeric_only: bool = True, min_count: int = -1
) -> "Tuple[List[Block], Index]":
# TODO: the actual managing of mgr_locs is a PITA
# here, it should happen via BlockManager.combine
data: BlockManager = self._get_data_to_aggregate()
if numeric_only:
data = data.get_numeric_data(copy=False)
agg_blocks: List[Block] = []
new_items: List[np.ndarray] = []
deleted_items: List[np.ndarray] = []
no_result = object()
for block in data.blocks:
# Avoid inheriting result from earlier in the loop
result = no_result
locs = block.mgr_locs.as_array
try:
result, _ = self.grouper.aggregate(
block.values, how, axis=1, min_count=min_count
)
except NotImplementedError:
# generally if we have numeric_only=False
# and non-applicable functions
# try to python agg
if alt is None:
# we cannot perform the operation
# in an alternate way, exclude the block
assert how == "ohlc"
deleted_items.append(locs)
continue
# call our grouper again with only this block
obj = self.obj[data.items[locs]]
if obj.shape[1] == 1:
# Avoid call to self.values that can occur in DataFrame
# reductions; see GH#28949
obj = obj.iloc[:, 0]
s = get_groupby(obj, self.grouper)
try:
result = s.aggregate(lambda x: alt(x, axis=self.axis))
except TypeError:
# we may have an exception in trying to aggregate
# continue and exclude the block
deleted_items.append(locs)
continue
else:
result = cast(DataFrame, result)
# unwrap DataFrame to get array
assert len(result._data.blocks) == 1
result = result._data.blocks[0].values
if isinstance(result, np.ndarray) and result.ndim == 1:
result = result.reshape(1, -1)
finally:
assert not isinstance(result, DataFrame)
if result is not no_result:
# see if we can cast the block back to the original dtype
result = maybe_downcast_numeric(result, block.dtype)
if block.is_extension and isinstance(result, np.ndarray):
# e.g. block.values was an IntegerArray
# (1, N) case can occur if block.values was Categorical
# and result is ndarray[object]
assert result.ndim == 1 or result.shape[0] == 1
try:
# Cast back if feasible
result = type(block.values)._from_sequence(
result.ravel(), dtype=block.values.dtype
)
except ValueError:
# reshape to be valid for non-Extension Block
result = result.reshape(1, -1)
agg_block: Block = block.make_block(result)
new_items.append(locs)
agg_blocks.append(agg_block)
if not agg_blocks:
raise DataError("No numeric types to aggregate")
# reset the locs in the blocks to correspond to our
# current ordering
indexer = np.concatenate(new_items)
agg_items = data.items.take(np.sort(indexer))
if deleted_items:
# we need to adjust the indexer to account for the
# items we have removed
# really should be done in internals :<
deleted = np.concatenate(deleted_items)
ai = np.arange(len(data))
mask = np.zeros(len(data))
mask[deleted] = 1
indexer = (ai - mask.cumsum())[indexer]
offset = 0
for blk in agg_blocks:
loc = len(blk.mgr_locs)
blk.mgr_locs = indexer[offset : (offset + loc)]
offset += loc
return agg_blocks, agg_items
def _aggregate_frame(self, func, *args, **kwargs) -> DataFrame:
if self.grouper.nkeys != 1:
raise AssertionError("Number of keys must be 1")
axis = self.axis
obj = self._obj_with_exclusions
result: OrderedDict = OrderedDict()
if axis != obj._info_axis_number:
for name, data in self:
fres = func(data, *args, **kwargs)
result[name] = fres
else:
for name in self.indices:
data = self.get_group(name, obj=obj)
fres = func(data, *args, **kwargs)
result[name] = fres
return self._wrap_frame_output(result, obj)
def _aggregate_item_by_item(self, func, *args, **kwargs) -> DataFrame:
# only for axis==0
obj = self._obj_with_exclusions
result: OrderedDict = OrderedDict()
cannot_agg = []
for item in obj:
data = obj[item]
colg = SeriesGroupBy(data, selection=item, grouper=self.grouper)
cast = self._transform_should_cast(func)
try:
result[item] = colg.aggregate(func, *args, **kwargs)
except ValueError as err:
if "Must produce aggregated value" in str(err):
# raised in _aggregate_named, handle at higher level
# see test_apply_with_mutated_index
raise
# otherwise we get here from an AttributeError in _make_wrapper
cannot_agg.append(item)
continue
else:
if cast:
result[item] = self._try_cast(result[item], data)
result_columns = obj.columns
if cannot_agg:
result_columns = result_columns.drop(cannot_agg)
return DataFrame(result, columns=result_columns)
def _wrap_applied_output(self, keys, values, not_indexed_same=False):
if len(keys) == 0:
return DataFrame(index=keys)
key_names = self.grouper.names
# GH12824.
def first_not_none(values):
try:
return next(com.not_none(*values))
except StopIteration:
return None
v = first_not_none(values)
if v is None:
# GH9684. If all values are None, then this will throw an error.
# We'd prefer it return an empty dataframe.
return DataFrame()
elif isinstance(v, DataFrame):
return self._concat_objects(keys, values, not_indexed_same=not_indexed_same)
elif self.grouper.groupings is not None:
if len(self.grouper.groupings) > 1:
key_index = self.grouper.result_index
else:
ping = self.grouper.groupings[0]
if len(keys) == ping.ngroups:
key_index = ping.group_index
key_index.name = key_names[0]
key_lookup = Index(keys)
indexer = key_lookup.get_indexer(key_index)
# reorder the values
values = [values[i] for i in indexer]
else:
key_index = Index(keys, name=key_names[0])
# don't use the key indexer
if not self.as_index:
key_index = None
# make Nones an empty object
v = first_not_none(values)
if v is None:
return DataFrame()
elif isinstance(v, NDFrame):
# this is to silence a DeprecationWarning
# TODO: Remove when default dtype of empty Series is object
kwargs = v._construct_axes_dict()
if v._constructor is Series:
backup = create_series_with_explicit_dtype(
**kwargs, dtype_if_empty=object
)
else:
backup = v._constructor(**kwargs)
values = [x if (x is not None) else backup for x in values]
v = values[0]
if isinstance(v, (np.ndarray, Index, Series)):
if isinstance(v, Series):
applied_index = self._selected_obj._get_axis(self.axis)
all_indexed_same = all_indexes_same([x.index for x in values])
singular_series = len(values) == 1 and applied_index.nlevels == 1
# GH3596
# provide a reduction (Frame -> Series) if groups are
# unique
if self.squeeze:
# assign the name to this series
if singular_series:
values[0].name = keys[0]
# GH2893
# we have series in the values array, we want to
# produce a series:
# if any of the sub-series are not indexed the same
# OR we don't have a multi-index and we have only a
# single values
return self._concat_objects(
keys, values, not_indexed_same=not_indexed_same
)
# still a series
# path added as of GH 5545
elif all_indexed_same:
from pandas.core.reshape.concat import concat
return concat(values)
if not all_indexed_same:
# GH 8467
return self._concat_objects(keys, values, not_indexed_same=True)
if self.axis == 0 and isinstance(v, ABCSeries):
# GH6124 if the list of Series have a consistent name,
# then propagate that name to the result.
index = v.index.copy()
if index.name is None:
# Only propagate the series name to the result
# if all series have a consistent name. If the
# series do not have a consistent name, do
# nothing.
names = {v.name for v in values}
if len(names) == 1:
index.name = list(names)[0]
# normally use vstack as its faster than concat
# and if we have mi-columns
if (
isinstance(v.index, MultiIndex)
or key_index is None
or isinstance(key_index, MultiIndex)
):
stacked_values = np.vstack([np.asarray(v) for v in values])
result = DataFrame(
stacked_values, index=key_index, columns=index
)
else:
# GH5788 instead of stacking; concat gets the
# dtypes correct
from pandas.core.reshape.concat import concat
result = concat(
values,
keys=key_index,
names=key_index.names,
axis=self.axis,
).unstack()
result.columns = index
elif isinstance(v, ABCSeries):
stacked_values = np.vstack([np.asarray(v) for v in values])
result = DataFrame(
stacked_values.T, index=v.index, columns=key_index
)
else:
# GH#1738: values is list of arrays of unequal lengths
# fall through to the outer else clause
# TODO: sure this is right? we used to do this
# after raising AttributeError above
return Series(values, index=key_index, name=self._selection_name)
# if we have date/time like in the original, then coerce dates
# as we are stacking can easily have object dtypes here
so = self._selected_obj
if so.ndim == 2 and so.dtypes.apply(needs_i8_conversion).any():
result = _recast_datetimelike_result(result)
else:
result = result._convert(datetime=True)
return self._reindex_output(result)
# values are not series or array-like but scalars
else:
# only coerce dates if we find at least 1 datetime
should_coerce = any(isinstance(x, Timestamp) for x in values)
# self._selection_name not passed through to Series as the
# result should not take the name of original selection
# of columns
return Series(values, index=key_index)._convert(
datetime=True, coerce=should_coerce
)
else:
# Handle cases like BinGrouper
return self._concat_objects(keys, values, not_indexed_same=not_indexed_same)
def _transform_general(self, func, *args, **kwargs):
from pandas.core.reshape.concat import concat
applied = []
obj = self._obj_with_exclusions
gen = self.grouper.get_iterator(obj, axis=self.axis)
fast_path, slow_path = self._define_paths(func, *args, **kwargs)
path = None
for name, group in gen:
object.__setattr__(group, "name", name)
if path is None:
# Try slow path and fast path.
try:
path, res = self._choose_path(fast_path, slow_path, group)
except TypeError:
return self._transform_item_by_item(obj, fast_path)
except ValueError:
msg = "transform must return a scalar value for each group"
raise ValueError(msg)
else:
res = path(group)
if isinstance(res, Series):
# we need to broadcast across the
# other dimension; this will preserve dtypes
# GH14457
if not np.prod(group.shape):
continue
elif res.index.is_(obj.index):
r = concat([res] * len(group.columns), axis=1)
r.columns = group.columns
r.index = group.index
else:
r = DataFrame(
np.concatenate([res.values] * len(group.index)).reshape(
group.shape
),
columns=group.columns,
index=group.index,
)
applied.append(r)
else:
applied.append(res)
concat_index = obj.columns if self.axis == 0 else obj.index
other_axis = 1 if self.axis == 0 else 0 # switches between 0 & 1
concatenated = concat(applied, axis=self.axis, verify_integrity=False)
concatenated = concatenated.reindex(concat_index, axis=other_axis, copy=False)
return self._set_result_index_ordered(concatenated)
@Substitution(klass="DataFrame", selected="")
@Appender(_transform_template)
def transform(self, func, *args, **kwargs):
# optimized transforms
func = self._get_cython_func(func) or func
if not isinstance(func, str):
return self._transform_general(func, *args, **kwargs)
elif func not in base.transform_kernel_whitelist:
msg = f"'{func}' is not a valid function name for transform(name)"
raise ValueError(msg)
elif func in base.cythonized_kernels:
# cythonized transformation or canned "reduction+broadcast"
return getattr(self, func)(*args, **kwargs)
# If func is a reduction, we need to broadcast the
# result to the whole group. Compute func result
# and deal with possible broadcasting below.
result = getattr(self, func)(*args, **kwargs)
# a reduction transform
if not isinstance(result, DataFrame):
return self._transform_general(func, *args, **kwargs)
obj = self._obj_with_exclusions
# nuisance columns
if not result.columns.equals(obj.columns):
return self._transform_general(func, *args, **kwargs)
return self._transform_fast(result, func)
def _transform_fast(self, result: DataFrame, func_nm: str) -> DataFrame:
"""
Fast transform path for aggregations
"""
# if there were groups with no observations (Categorical only?)
# try casting data to original dtype
cast = self._transform_should_cast(func_nm)
obj = self._obj_with_exclusions
# for each col, reshape to to size of original frame
# by take operation
ids, _, ngroup = self.grouper.group_info
output = []
for i, _ in enumerate(result.columns):
res = algorithms.take_1d(result.iloc[:, i].values, ids)
# TODO: we have no test cases that get here with EA dtypes;
# try_cast may not be needed if EAs never get here
if cast:
res = self._try_cast(res, obj.iloc[:, i])
output.append(res)
return DataFrame._from_arrays(output, columns=result.columns, index=obj.index)
def _define_paths(self, func, *args, **kwargs):
if isinstance(func, str):
fast_path = lambda group: getattr(group, func)(*args, **kwargs)
slow_path = lambda group: group.apply(
lambda x: getattr(x, func)(*args, **kwargs), axis=self.axis
)
else:
fast_path = lambda group: func(group, *args, **kwargs)
slow_path = lambda group: group.apply(
lambda x: func(x, *args, **kwargs), axis=self.axis
)
return fast_path, slow_path
def _choose_path(self, fast_path: Callable, slow_path: Callable, group: DataFrame):
path = slow_path
res = slow_path(group)
# if we make it here, test if we can use the fast path
try:
res_fast = fast_path(group)
except AssertionError:
raise
except Exception:
# GH#29631 For user-defined function, we cant predict what may be
# raised; see test_transform.test_transform_fastpath_raises
return path, res
# verify fast path does not change columns (and names), otherwise
# its results cannot be joined with those of the slow path
if not isinstance(res_fast, DataFrame):
return path, res
if not res_fast.columns.equals(group.columns):
return path, res
if res_fast.equals(res):
path = fast_path
return path, res
def _transform_item_by_item(self, obj: DataFrame, wrapper) -> DataFrame:
# iterate through columns
output = {}
inds = []
for i, col in enumerate(obj):
try:
output[col] = self[col].transform(wrapper)
except TypeError:
# e.g. trying to call nanmean with string values
pass
else:
inds.append(i)
if len(output) == 0:
raise TypeError("Transform function invalid for data types")
columns = obj.columns
if len(output) < len(obj.columns):
columns = columns.take(inds)
return DataFrame(output, index=obj.index, columns=columns)
def filter(self, func, dropna=True, *args, **kwargs):
"""
Return a copy of a DataFrame excluding elements from groups that
do not satisfy the boolean criterion specified by func.
Parameters
----------
f : function
Function to apply to each subframe. Should return True or False.
dropna : Drop groups that do not pass the filter. True by default;
If False, groups that evaluate False are filled with NaNs.
Returns
-------
filtered : DataFrame
Notes
-----
Each subframe is endowed the attribute 'name' in case you need to know
which group you are working on.
Examples
--------
>>> df = pd.DataFrame({'A' : ['foo', 'bar', 'foo', 'bar',
... 'foo', 'bar'],
... 'B' : [1, 2, 3, 4, 5, 6],
... 'C' : [2.0, 5., 8., 1., 2., 9.]})
>>> grouped = df.groupby('A')
>>> grouped.filter(lambda x: x['B'].mean() > 3.)
A B C
1 bar 2 5.0
3 bar 4 1.0
5 bar 6 9.0
"""
indices = []
obj = self._selected_obj
gen = self.grouper.get_iterator(obj, axis=self.axis)
for name, group in gen:
object.__setattr__(group, "name", name)
res = func(group, *args, **kwargs)
try:
res = res.squeeze()
except AttributeError: # allow e.g., scalars and frames to pass
pass
# interpret the result of the filter
if is_bool(res) or (is_scalar(res) and isna(res)):
if res and notna(res):
indices.append(self._get_index(name))
else:
# non scalars aren't allowed
raise TypeError(
f"filter function returned a {type(res).__name__}, "
"but expected a scalar bool"
)
return self._apply_filter(indices, dropna)
def _gotitem(self, key, ndim: int, subset=None):
"""
sub-classes to define
return a sliced object
Parameters
----------
key : string / list of selections
ndim : 1,2
requested ndim of result
subset : object, default None
subset to act on
"""
if ndim == 2:
if subset is None:
subset = self.obj
return DataFrameGroupBy(
subset,
self.grouper,
selection=key,
grouper=self.grouper,
exclusions=self.exclusions,
as_index=self.as_index,
observed=self.observed,
)
elif ndim == 1:
if subset is None:
subset = self.obj[key]
return SeriesGroupBy(
subset, selection=key, grouper=self.grouper, observed=self.observed
)
raise AssertionError("invalid ndim for _gotitem")
def _wrap_frame_output(self, result, obj) -> DataFrame:
result_index = self.grouper.levels[0]
if self.axis == 0:
return DataFrame(result, index=obj.columns, columns=result_index).T
else:
return DataFrame(result, index=obj.index, columns=result_index)
def _get_data_to_aggregate(self) -> BlockManager:
obj = self._obj_with_exclusions
if self.axis == 1:
return obj.T._data
else:
return obj._data
def _insert_inaxis_grouper_inplace(self, result):
# zip in reverse so we can always insert at loc 0
izip = zip(
*map(
reversed,
(
self.grouper.names,
self.grouper.get_group_levels(),
[grp.in_axis for grp in self.grouper.groupings],
),
)
)
for name, lev, in_axis in izip:
if in_axis:
result.insert(0, name, lev)
def _wrap_aggregated_output(
self, output: Mapping[base.OutputKey, Union[Series, np.ndarray]]
) -> DataFrame:
"""
Wraps the output of DataFrameGroupBy aggregations into the expected result.
Parameters
----------
output : Mapping[base.OutputKey, Union[Series, np.ndarray]]
Data to wrap.
Returns
-------
DataFrame
"""
indexed_output = {key.position: val for key, val in output.items()}
columns = Index(key.label for key in output)
result = DataFrame(indexed_output)
result.columns = columns
if not self.as_index:
self._insert_inaxis_grouper_inplace(result)
result = result._consolidate()
else:
index = self.grouper.result_index
result.index = index
if self.axis == 1:
result = result.T
return self._reindex_output(result)._convert(datetime=True)
def _wrap_transformed_output(
self, output: Mapping[base.OutputKey, Union[Series, np.ndarray]]
) -> DataFrame:
"""
Wraps the output of DataFrameGroupBy transformations into the expected result.
Parameters
----------
output : Mapping[base.OutputKey, Union[Series, np.ndarray]]
Data to wrap.
Returns
-------
DataFrame
"""
indexed_output = {key.position: val for key, val in output.items()}
columns = Index(key.label for key in output)
result = DataFrame(indexed_output)
result.columns = columns
result.index = self.obj.index
return result
def _wrap_agged_blocks(self, blocks: "Sequence[Block]", items: Index) -> DataFrame:
if not self.as_index:
index = np.arange(blocks[0].values.shape[-1])
mgr = BlockManager(blocks, axes=[items, index])
result = DataFrame(mgr)
self._insert_inaxis_grouper_inplace(result)
result = result._consolidate()
else:
index = self.grouper.result_index
mgr = BlockManager(blocks, axes=[items, index])
result = DataFrame(mgr)
if self.axis == 1:
result = result.T
return self._reindex_output(result)._convert(datetime=True)
def _iterate_column_groupbys(self):
for i, colname in enumerate(self._selected_obj.columns):
yield colname, SeriesGroupBy(
self._selected_obj.iloc[:, i],
selection=colname,
grouper=self.grouper,
exclusions=self.exclusions,
)
def _apply_to_column_groupbys(self, func):
from pandas.core.reshape.concat import concat
return concat(
(func(col_groupby) for _, col_groupby in self._iterate_column_groupbys()),
keys=self._selected_obj.columns,
axis=1,
)
def count(self):
"""
Compute count of group, excluding missing values.
Returns
-------
DataFrame
Count of values within each group.
"""
data = self._get_data_to_aggregate()
ids, _, ngroups = self.grouper.group_info
mask = ids != -1
vals = (
(mask & ~_isna_ndarraylike(np.atleast_2d(blk.get_values())))
for blk in data.blocks
)
locs = (blk.mgr_locs for blk in data.blocks)
counted = (
lib.count_level_2d(x, labels=ids, max_bin=ngroups, axis=1) for x in vals
)
blocks = [make_block(val, placement=loc) for val, loc in zip(counted, locs)]
return self._wrap_agged_blocks(blocks, items=data.items)
def nunique(self, dropna: bool = True):
"""
Return DataFrame with number of distinct observations per group for
each column.
Parameters
----------
dropna : bool, default True
Don't include NaN in the counts.
Returns
-------
nunique: DataFrame
Examples
--------
>>> df = pd.DataFrame({'id': ['spam', 'egg', 'egg', 'spam',
... 'ham', 'ham'],
... 'value1': [1, 5, 5, 2, 5, 5],
... 'value2': list('abbaxy')})
>>> df
id value1 value2
0 spam 1 a
1 egg 5 b
2 egg 5 b
3 spam 2 a
4 ham 5 x
5 ham 5 y
>>> df.groupby('id').nunique()
id value1 value2
id
egg 1 1 1
ham 1 1 2
spam 1 2 1
Check for rows with the same id but conflicting values:
>>> df.groupby('id').filter(lambda g: (g.nunique() > 1).any())
id value1 value2
0 spam 1 a
3 spam 2 a
4 ham 5 x
5 ham 5 y
"""
obj = self._selected_obj
def groupby_series(obj, col=None):
return SeriesGroupBy(obj, selection=col, grouper=self.grouper).nunique(
dropna=dropna
)
if isinstance(obj, Series):
results = groupby_series(obj)
else:
# TODO: this is duplicative of how GroupBy naturally works
# Try to consolidate with normal wrapping functions
from pandas.core.reshape.concat import concat
axis_number = obj._get_axis_number(self.axis)
other_axis = int(not axis_number)
if axis_number == 0:
iter_func = obj.items
else:
iter_func = obj.iterrows
results = [groupby_series(content, label) for label, content in iter_func()]
results = concat(results, axis=1)
if axis_number == 1:
results = results.T
results._get_axis(other_axis).names = obj._get_axis(other_axis).names
if not self.as_index:
results.index = ibase.default_index(len(results))
return results
boxplot = boxplot_frame_groupby
def _is_multi_agg_with_relabel(**kwargs) -> bool:
"""
Check whether kwargs passed to .agg look like multi-agg with relabeling.
Parameters
----------
**kwargs : dict
Returns
-------
bool
Examples
--------
>>> _is_multi_agg_with_relabel(a='max')
False
>>> _is_multi_agg_with_relabel(a_max=('a', 'max'),
... a_min=('a', 'min'))
True
>>> _is_multi_agg_with_relabel()
False
"""
return all(isinstance(v, tuple) and len(v) == 2 for v in kwargs.values()) and (
len(kwargs) > 0
)
def _normalize_keyword_aggregation(kwargs):
"""
Normalize user-provided "named aggregation" kwargs.
Transforms from the new ``Mapping[str, NamedAgg]`` style kwargs
to the old OrderedDict[str, List[scalar]]].
Parameters
----------
kwargs : dict
Returns
-------
aggspec : dict
The transformed kwargs.
columns : List[str]
The user-provided keys.
col_idx_order : List[int]
List of columns indices.
Examples
--------
>>> _normalize_keyword_aggregation({'output': ('input', 'sum')})
(OrderedDict([('input', ['sum'])]), ('output',), [('input', 'sum')])
"""
# Normalize the aggregation functions as Mapping[column, List[func]],
# process normally, then fixup the names.
# TODO: aggspec type: typing.OrderedDict[str, List[AggScalar]]
# May be hitting https://github.com/python/mypy/issues/5958
# saying it doesn't have an attribute __name__
aggspec = defaultdict(list)
order = []
columns, pairs = list(zip(*kwargs.items()))
for name, (column, aggfunc) in zip(columns, pairs):
aggspec[column].append(aggfunc)
order.append((column, com.get_callable_name(aggfunc) or aggfunc))
# uniquify aggfunc name if duplicated in order list
uniquified_order = _make_unique(order)
# GH 25719, due to aggspec will change the order of assigned columns in aggregation
# uniquified_aggspec will store uniquified order list and will compare it with order
# based on index
aggspec_order = [
(column, com.get_callable_name(aggfunc) or aggfunc)
for column, aggfuncs in aggspec.items()
for aggfunc in aggfuncs
]
uniquified_aggspec = _make_unique(aggspec_order)
# get the new indice of columns by comparison
col_idx_order = Index(uniquified_aggspec).get_indexer(uniquified_order)
return aggspec, columns, col_idx_order
def _make_unique(seq):
"""Uniquify aggfunc name of the pairs in the order list
Examples:
--------
>>> _make_unique([('a', '<lambda>'), ('a', '<lambda>'), ('b', '<lambda>')])
[('a', '<lambda>_0'), ('a', '<lambda>_1'), ('b', '<lambda>')]
"""
return [
(pair[0], "_".join([pair[1], str(seq[:i].count(pair))]))
if seq.count(pair) > 1
else pair
for i, pair in enumerate(seq)
]
# TODO: Can't use, because mypy doesn't like us setting __name__
# error: "partial[Any]" has no attribute "__name__"
# the type is:
# typing.Sequence[Callable[..., ScalarResult]]
# -> typing.Sequence[Callable[..., ScalarResult]]:
def _managle_lambda_list(aggfuncs: Sequence[Any]) -> Sequence[Any]:
"""
Possibly mangle a list of aggfuncs.
Parameters
----------
aggfuncs : Sequence
Returns
-------
mangled: list-like
A new AggSpec sequence, where lambdas have been converted
to have unique names.
Notes
-----
If just one aggfunc is passed, the name will not be mangled.
"""
if len(aggfuncs) <= 1:
# don't mangle for .agg([lambda x: .])
return aggfuncs
i = 0
mangled_aggfuncs = []
for aggfunc in aggfuncs:
if com.get_callable_name(aggfunc) == "<lambda>":
aggfunc = partial(aggfunc)
aggfunc.__name__ = f"<lambda_{i}>"
i += 1
mangled_aggfuncs.append(aggfunc)
return mangled_aggfuncs
def _maybe_mangle_lambdas(agg_spec: Any) -> Any:
"""
Make new lambdas with unique names.
Parameters
----------
agg_spec : Any
An argument to GroupBy.agg.
Non-dict-like `agg_spec` are pass through as is.
For dict-like `agg_spec` a new spec is returned
with name-mangled lambdas.
Returns
-------
mangled : Any
Same type as the input.
Examples
--------
>>> _maybe_mangle_lambdas('sum')
'sum'
>>> _maybe_mangle_lambdas([lambda: 1, lambda: 2]) # doctest: +SKIP
[<function __main__.<lambda_0>,
<function pandas...._make_lambda.<locals>.f(*args, **kwargs)>]
"""
is_dict = is_dict_like(agg_spec)
if not (is_dict or is_list_like(agg_spec)):
return agg_spec
mangled_aggspec = type(agg_spec)() # dict or OrderdDict
if is_dict:
for key, aggfuncs in agg_spec.items():
if is_list_like(aggfuncs) and not is_dict_like(aggfuncs):
mangled_aggfuncs = _managle_lambda_list(aggfuncs)
else:
mangled_aggfuncs = aggfuncs
mangled_aggspec[key] = mangled_aggfuncs
else:
mangled_aggspec = _managle_lambda_list(agg_spec)
return mangled_aggspec
def _recast_datetimelike_result(result: DataFrame) -> DataFrame:
"""
If we have date/time like in the original, then coerce dates
as we are stacking can easily have object dtypes here.
Parameters
----------
result : DataFrame
Returns
-------
DataFrame
Notes
-----
- Assumes Groupby._selected_obj has ndim==2 and at least one
datetimelike column
"""
result = result.copy()
obj_cols = [
idx
for idx in range(len(result.columns))
if is_object_dtype(result.dtypes.iloc[idx])
]
# See GH#26285
for n in obj_cols:
converted = maybe_convert_objects(
result.iloc[:, n].values, convert_numeric=False
)
result.iloc[:, n] = converted
return result
"""
Define the SeriesGroupBy and DataFrameGroupBy
classes that hold the groupby interfaces (and some implementations).
These are user facing as the result of the ``df.groupby(...)`` operations,
which here returns a DataFrameGroupBy object.
"""
from collections import OrderedDict, abc, defaultdict, namedtuple
import copy
from functools import partial
from textwrap import dedent
import typing
from typing import (
TYPE_CHECKING,
Any,
Callable,
FrozenSet,
Iterable,
List,
Mapping,
Sequence,
Tuple,
Type,
Union,
cast,
)
import numpy as np
from pandas._libs import Timestamp, lib
from pandas._typing import FrameOrSeries
from pandas.util._decorators import Appender, Substitution
from pandas.core.dtypes.cast import (
maybe_convert_objects,
maybe_downcast_numeric,
maybe_downcast_to_dtype,
)
from pandas.core.dtypes.common import (
ensure_int64,
ensure_platform_int,
is_bool,
is_dict_like,
is_integer_dtype,
is_interval_dtype,
is_list_like,
is_numeric_dtype,
is_object_dtype,
is_scalar,
needs_i8_conversion,
)
from pandas.core.dtypes.missing import _isna_ndarraylike, isna, notna
import pandas.core.algorithms as algorithms
from pandas.core.base import DataError, SpecificationError
import pandas.core.common as com
from pandas.core.construction import create_series_with_explicit_dtype
from pandas.core.frame import DataFrame
from pandas.core.generic import ABCDataFrame, ABCSeries, NDFrame, _shared_docs
from pandas.core.groupby import base
from pandas.core.groupby.groupby import (
GroupBy,
_apply_docs,
_transform_template,
get_groupby,
)
from pandas.core.indexes.api import Index, MultiIndex, all_indexes_same
import pandas.core.indexes.base as ibase
from pandas.core.internals import BlockManager, make_block
from pandas.core.series import Series
from pandas.plotting import boxplot_frame_groupby
if TYPE_CHECKING:
from pandas.core.internals import Block
NamedAgg = namedtuple("NamedAgg", ["column", "aggfunc"])
# TODO(typing) the return value on this callable should be any *scalar*.
AggScalar = Union[str, Callable[..., Any]]
# TODO: validate types on ScalarResult and move to _typing
# Blocked from using by https://github.com/python/mypy/issues/1484
# See note at _mangle_lambda_list
ScalarResult = typing.TypeVar("ScalarResult")
def generate_property(name: str, klass: Type[FrameOrSeries]):
"""
Create a property for a GroupBy subclass to dispatch to DataFrame/Series.
Parameters
----------
name : str
klass : {DataFrame, Series}
Returns
-------
property
"""
def prop(self):
return self._make_wrapper(name)
parent_method = getattr(klass, name)
prop.__doc__ = parent_method.__doc__ or ""
prop.__name__ = name
return property(prop)
def pin_whitelisted_properties(klass: Type[FrameOrSeries], whitelist: FrozenSet[str]):
"""
Create GroupBy member defs for DataFrame/Series names in a whitelist.
Parameters
----------
klass : DataFrame or Series class
class where members are defined.
whitelist : frozenset[str]
Set of names of klass methods to be constructed
Returns
-------
class decorator
Notes
-----
Since we don't want to override methods explicitly defined in the
base class, any such name is skipped.
"""
def pinner(cls):
for name in whitelist:
if hasattr(cls, name):
# don't override anything that was explicitly defined
# in the base class
continue
prop = generate_property(name, klass)
setattr(cls, name, prop)
return cls
return pinner
@pin_whitelisted_properties(Series, base.series_apply_whitelist)
class SeriesGroupBy(GroupBy):
_apply_whitelist = base.series_apply_whitelist
def _iterate_slices(self) -> Iterable[Series]:
yield self._selected_obj
@property
def _selection_name(self):
"""
since we are a series, we by definition only have
a single name, but may be the result of a selection or
the name of our object
"""
if self._selection is None:
return self.obj.name
else:
return self._selection
_agg_see_also_doc = dedent(
"""
See Also
--------
pandas.Series.groupby.apply
pandas.Series.groupby.transform
pandas.Series.aggregate
"""
)
_agg_examples_doc = dedent(
"""
Examples
--------
>>> s = pd.Series([1, 2, 3, 4])
>>> s
0 1
1 2
2 3
3 4
dtype: int64
>>> s.groupby([1, 1, 2, 2]).min()
1 1
2 3
dtype: int64
>>> s.groupby([1, 1, 2, 2]).agg('min')
1 1
2 3
dtype: int64
>>> s.groupby([1, 1, 2, 2]).agg(['min', 'max'])
min max
1 1 2
2 3 4
The output column names can be controlled by passing
the desired column names and aggregations as keyword arguments.
>>> s.groupby([1, 1, 2, 2]).agg(
... minimum='min',
... maximum='max',
... )
minimum maximum
1 1 2
2 3 4
"""
)
@Appender(
_apply_docs["template"].format(
input="series", examples=_apply_docs["series_examples"]
)
)
def apply(self, func, *args, **kwargs):
return super().apply(func, *args, **kwargs)
@Substitution(
see_also=_agg_see_also_doc,
examples=_agg_examples_doc,
versionadded="",
klass="Series",
axis="",
)
@Appender(_shared_docs["aggregate"])
def aggregate(self, func=None, *args, **kwargs):
relabeling = func is None
columns = None
no_arg_message = "Must provide 'func' or named aggregation **kwargs."
if relabeling:
columns = list(kwargs)
func = [kwargs[col] for col in columns]
kwargs = {}
if not columns:
raise TypeError(no_arg_message)
if isinstance(func, str):
return getattr(self, func)(*args, **kwargs)
elif isinstance(func, abc.Iterable):
# Catch instances of lists / tuples
# but not the class list / tuple itself.
func = _maybe_mangle_lambdas(func)
ret = self._aggregate_multiple_funcs(func)
if relabeling:
ret.columns = columns
else:
cyfunc = self._get_cython_func(func)
if cyfunc and not args and not kwargs:
return getattr(self, cyfunc)()
if self.grouper.nkeys > 1:
return self._python_agg_general(func, *args, **kwargs)
try:
return self._python_agg_general(func, *args, **kwargs)
except (ValueError, KeyError):
# TODO: KeyError is raised in _python_agg_general,
# see see test_groupby.test_basic
result = self._aggregate_named(func, *args, **kwargs)
index = Index(sorted(result), name=self.grouper.names[0])
ret = create_series_with_explicit_dtype(
result, index=index, dtype_if_empty=object
)
if not self.as_index: # pragma: no cover
print("Warning, ignoring as_index=True")
if isinstance(ret, dict):
from pandas import concat
ret = concat(ret, axis=1)
return ret
agg = aggregate
def _aggregate_multiple_funcs(self, arg):
if isinstance(arg, dict):
# show the deprecation, but only if we
# have not shown a higher level one
# GH 15931
if isinstance(self._selected_obj, Series):
raise SpecificationError("nested renamer is not supported")
columns = list(arg.keys())
arg = arg.items()
elif any(isinstance(x, (tuple, list)) for x in arg):
arg = [(x, x) if not isinstance(x, (tuple, list)) else x for x in arg]
# indicated column order
columns = next(zip(*arg))
else:
# list of functions / function names
columns = []
for f in arg:
columns.append(com.get_callable_name(f) or f)
arg = zip(columns, arg)
results = OrderedDict()
for name, func in arg:
obj = self
# reset the cache so that we
# only include the named selection
if name in self._selected_obj:
obj = copy.copy(obj)
obj._reset_cache()
obj._selection = name
results[name] = obj.aggregate(func)
if any(isinstance(x, DataFrame) for x in results.values()):
# let higher level handle
return results
return DataFrame(results, columns=columns)
def _wrap_series_output(
self, output: Mapping[base.OutputKey, Union[Series, np.ndarray]], index: Index,
) -> Union[Series, DataFrame]:
"""
Wraps the output of a SeriesGroupBy operation into the expected result.
Parameters
----------
output : Mapping[base.OutputKey, Union[Series, np.ndarray]]
Data to wrap.
index : pd.Index
Index to apply to the output.
Returns
-------
Series or DataFrame
Notes
-----
In the vast majority of cases output and columns will only contain one
element. The exception is operations that expand dimensions, like ohlc.
"""
indexed_output = {key.position: val for key, val in output.items()}
columns = Index(key.label for key in output)
result: Union[Series, DataFrame]
if len(output) > 1:
result = DataFrame(indexed_output, index=index)
result.columns = columns
else:
result = Series(indexed_output[0], index=index, name=columns[0])
return result
def _wrap_aggregated_output(
self, output: Mapping[base.OutputKey, Union[Series, np.ndarray]]
) -> Union[Series, DataFrame]:
"""
Wraps the output of a SeriesGroupBy aggregation into the expected result.
Parameters
----------
output : Mapping[base.OutputKey, Union[Series, np.ndarray]]
Data to wrap.
Returns
-------
Series or DataFrame
Notes
-----
In the vast majority of cases output will only contain one element.
The exception is operations that expand dimensions, like ohlc.
"""
result = self._wrap_series_output(
output=output, index=self.grouper.result_index
)
return self._reindex_output(result)._convert(datetime=True)
def _wrap_transformed_output(
self, output: Mapping[base.OutputKey, Union[Series, np.ndarray]]
) -> Series:
"""
Wraps the output of a SeriesGroupBy aggregation into the expected result.
Parameters
----------
output : dict[base.OutputKey, Union[Series, np.ndarray]]
Dict with a sole key of 0 and a value of the result values.
Returns
-------
Series
Notes
-----
output should always contain one element. It is specified as a dict
for consistency with DataFrame methods and _wrap_aggregated_output.
"""
assert len(output) == 1
result = self._wrap_series_output(output=output, index=self.obj.index)
# No transformations increase the ndim of the result
assert isinstance(result, Series)
return result
def _wrap_applied_output(self, keys, values, not_indexed_same=False):
if len(keys) == 0:
# GH #6265
return Series([], name=self._selection_name, index=keys, dtype=np.float64)
def _get_index() -> Index:
if self.grouper.nkeys > 1:
index = MultiIndex.from_tuples(keys, names=self.grouper.names)
else:
index = Index(keys, name=self.grouper.names[0])
return index
if isinstance(values[0], dict):
# GH #823 #24880
index = _get_index()
result = self._reindex_output(DataFrame(values, index=index))
# if self.observed is False,
# keep all-NaN rows created while re-indexing
result = result.stack(dropna=self.observed)
result.name = self._selection_name
return result
if isinstance(values[0], Series):
return self._concat_objects(keys, values, not_indexed_same=not_indexed_same)
elif isinstance(values[0], DataFrame):
# possible that Series -> DataFrame by applied function
return self._concat_objects(keys, values, not_indexed_same=not_indexed_same)
else:
# GH #6265 #24880
result = Series(data=values, index=_get_index(), name=self._selection_name)
return self._reindex_output(result)
def _aggregate_named(self, func, *args, **kwargs):
result = OrderedDict()
for name, group in self:
group.name = name
output = func(group, *args, **kwargs)
if isinstance(output, (Series, Index, np.ndarray)):
raise ValueError("Must produce aggregated value")
result[name] = output
return result
@Substitution(klass="Series", selected="A.")
@Appender(_transform_template)
def transform(self, func, *args, **kwargs):
func = self._get_cython_func(func) or func
if not isinstance(func, str):
return self._transform_general(func, *args, **kwargs)
elif func not in base.transform_kernel_whitelist:
msg = f"'{func}' is not a valid function name for transform(name)"
raise ValueError(msg)
elif func in base.cythonized_kernels:
# cythonized transform or canned "agg+broadcast"
return getattr(self, func)(*args, **kwargs)
# If func is a reduction, we need to broadcast the
# result to the whole group. Compute func result
# and deal with possible broadcasting below.
result = getattr(self, func)(*args, **kwargs)
return self._transform_fast(result, func)
def _transform_general(self, func, *args, **kwargs):
"""
Transform with a non-str `func`.
"""
klass = type(self._selected_obj)
results = []
for name, group in self:
object.__setattr__(group, "name", name)
res = func(group, *args, **kwargs)
if isinstance(res, (ABCDataFrame, ABCSeries)):
res = res._values
indexer = self._get_index(name)
ser = klass(res, indexer)
results.append(ser)
# check for empty "results" to avoid concat ValueError
if results:
from pandas.core.reshape.concat import concat
result = concat(results).sort_index()
else:
result = Series(dtype=np.float64)
# we will only try to coerce the result type if
# we have a numeric dtype, as these are *always* user-defined funcs
# the cython take a different path (and casting)
dtype = self._selected_obj.dtype
if is_numeric_dtype(dtype):
result = maybe_downcast_to_dtype(result, dtype)
result.name = self._selected_obj.name
result.index = self._selected_obj.index
return result
def _transform_fast(self, result, func_nm: str) -> Series:
"""
fast version of transform, only applicable to
builtin/cythonizable functions
"""
ids, _, ngroup = self.grouper.group_info
cast = self._transform_should_cast(func_nm)
out = algorithms.take_1d(result._values, ids)
if cast:
out = self._try_cast(out, self.obj)
return Series(out, index=self.obj.index, name=self.obj.name)
def filter(self, func, dropna=True, *args, **kwargs):
"""
Return a copy of a Series excluding elements from groups that
do not satisfy the boolean criterion specified by func.
Parameters
----------
func : function
To apply to each group. Should return True or False.
dropna : Drop groups that do not pass the filter. True by default;
if False, groups that evaluate False are filled with NaNs.
Examples
--------
>>> df = pd.DataFrame({'A' : ['foo', 'bar', 'foo', 'bar',
... 'foo', 'bar'],
... 'B' : [1, 2, 3, 4, 5, 6],
... 'C' : [2.0, 5., 8., 1., 2., 9.]})
>>> grouped = df.groupby('A')
>>> df.groupby('A').B.filter(lambda x: x.mean() > 3.)
1 2
3 4
5 6
Name: B, dtype: int64
Returns
-------
filtered : Series
"""
if isinstance(func, str):
wrapper = lambda x: getattr(x, func)(*args, **kwargs)
else:
wrapper = lambda x: func(x, *args, **kwargs)
# Interpret np.nan as False.
def true_and_notna(x, *args, **kwargs) -> bool:
b = wrapper(x, *args, **kwargs)
return b and notna(b)
try:
indices = [
self._get_index(name) for name, group in self if true_and_notna(group)
]
except (ValueError, TypeError):
raise TypeError("the filter must return a boolean result")
filtered = self._apply_filter(indices, dropna)
return filtered
def nunique(self, dropna: bool = True) -> Series:
"""
Return number of unique elements in the group.
Returns
-------
Series
Number of unique values within each group.
"""
ids, _, _ = self.grouper.group_info
val = self.obj._internal_get_values()
# GH 27951
# temporary fix while we wait for NumPy bug 12629 to be fixed
val[isna(val)] = np.datetime64("NaT")
try:
sorter = np.lexsort((val, ids))
except TypeError: # catches object dtypes
msg = f"val.dtype must be object, got {val.dtype}"
assert val.dtype == object, msg
val, _ = algorithms.factorize(val, sort=False)
sorter = np.lexsort((val, ids))
_isna = lambda a: a == -1
else:
_isna = isna
ids, val = ids[sorter], val[sorter]
# group boundaries are where group ids change
# unique observations are where sorted values change
idx = np.r_[0, 1 + np.nonzero(ids[1:] != ids[:-1])[0]]
inc = np.r_[1, val[1:] != val[:-1]]
# 1st item of each group is a new unique observation
mask = _isna(val)
if dropna:
inc[idx] = 1
inc[mask] = 0
else:
inc[mask & np.r_[False, mask[:-1]]] = 0
inc[idx] = 1
out = np.add.reduceat(inc, idx).astype("int64", copy=False)
if len(ids):
# NaN/NaT group exists if the head of ids is -1,
# so remove it from res and exclude its index from idx
if ids[0] == -1:
res = out[1:]
idx = idx[np.flatnonzero(idx)]
else:
res = out
else:
res = out[1:]
ri = self.grouper.result_index
# we might have duplications among the bins
if len(res) != len(ri):
res, out = np.zeros(len(ri), dtype=out.dtype), res
res[ids[idx]] = out
result = Series(res, index=ri, name=self._selection_name)
return self._reindex_output(result, fill_value=0)
@Appender(Series.describe.__doc__)
def describe(self, **kwargs):
result = self.apply(lambda x: x.describe(**kwargs))
if self.axis == 1:
return result.T
return result.unstack()
def value_counts(
self, normalize=False, sort=True, ascending=False, bins=None, dropna=True
):
from pandas.core.reshape.tile import cut
from pandas.core.reshape.merge import _get_join_indexers
if bins is not None and not np.iterable(bins):
# scalar bins cannot be done at top level
# in a backward compatible way
return self.apply(
Series.value_counts,
normalize=normalize,
sort=sort,
ascending=ascending,
bins=bins,
)
ids, _, _ = self.grouper.group_info
val = self.obj._internal_get_values()
# groupby removes null keys from groupings
mask = ids != -1
ids, val = ids[mask], val[mask]
if bins is None:
lab, lev = algorithms.factorize(val, sort=True)
llab = lambda lab, inc: lab[inc]
else:
# lab is a Categorical with categories an IntervalIndex
lab = cut(Series(val), bins, include_lowest=True)
lev = lab.cat.categories
lab = lev.take(lab.cat.codes)
llab = lambda lab, inc: lab[inc]._multiindex.codes[-1]
if is_interval_dtype(lab):
# TODO: should we do this inside II?
sorter = np.lexsort((lab.left, lab.right, ids))
else:
sorter = np.lexsort((lab, ids))
ids, lab = ids[sorter], lab[sorter]
# group boundaries are where group ids change
idx = np.r_[0, 1 + np.nonzero(ids[1:] != ids[:-1])[0]]
# new values are where sorted labels change
lchanges = llab(lab, slice(1, None)) != llab(lab, slice(None, -1))
inc = np.r_[True, lchanges]
inc[idx] = True # group boundaries are also new values
out = np.diff(np.nonzero(np.r_[inc, True])[0]) # value counts
# num. of times each group should be repeated
rep = partial(np.repeat, repeats=np.add.reduceat(inc, idx))
# multi-index components
codes = self.grouper.reconstructed_codes
codes = [rep(level_codes) for level_codes in codes] + [llab(lab, inc)]
levels = [ping.group_index for ping in self.grouper.groupings] + [lev]
names = self.grouper.names + [self._selection_name]
if dropna:
mask = codes[-1] != -1
if mask.all():
dropna = False
else:
out, codes = out[mask], [level_codes[mask] for level_codes in codes]
if normalize:
out = out.astype("float")
d = np.diff(np.r_[idx, len(ids)])
if dropna:
m = ids[lab == -1]
np.add.at(d, m, -1)
acc = rep(d)[mask]
else:
acc = rep(d)
out /= acc
if sort and bins is None:
cat = ids[inc][mask] if dropna else ids[inc]
sorter = np.lexsort((out if ascending else -out, cat))
out, codes[-1] = out[sorter], codes[-1][sorter]
if bins is None:
mi = MultiIndex(
levels=levels, codes=codes, names=names, verify_integrity=False
)
if is_integer_dtype(out):
out = ensure_int64(out)
return Series(out, index=mi, name=self._selection_name)
# for compat. with libgroupby.value_counts need to ensure every
# bin is present at every index level, null filled with zeros
diff = np.zeros(len(out), dtype="bool")
for level_codes in codes[:-1]:
diff |= np.r_[True, level_codes[1:] != level_codes[:-1]]
ncat, nbin = diff.sum(), len(levels[-1])
left = [np.repeat(np.arange(ncat), nbin), np.tile(np.arange(nbin), ncat)]
right = [diff.cumsum() - 1, codes[-1]]
_, idx = _get_join_indexers(left, right, sort=False, how="left")
out = np.where(idx != -1, out[idx], 0)
if sort:
sorter = np.lexsort((out if ascending else -out, left[0]))
out, left[-1] = out[sorter], left[-1][sorter]
# build the multi-index w/ full levels
def build_codes(lev_codes: np.ndarray) -> np.ndarray:
return np.repeat(lev_codes[diff], nbin)
codes = [build_codes(lev_codes) for lev_codes in codes[:-1]]
codes.append(left[-1])
mi = MultiIndex(levels=levels, codes=codes, names=names, verify_integrity=False)
if is_integer_dtype(out):
out = ensure_int64(out)
return Series(out, index=mi, name=self._selection_name)
def count(self) -> Series:
"""
Compute count of group, excluding missing values.
Returns
-------
Series
Count of values within each group.
"""
ids, _, ngroups = self.grouper.group_info
val = self.obj._internal_get_values()
mask = (ids != -1) & ~isna(val)
ids = ensure_platform_int(ids)
minlength = ngroups or 0
out = np.bincount(ids[mask], minlength=minlength)
result = Series(
out,
index=self.grouper.result_index,
name=self._selection_name,
dtype="int64",
)
return self._reindex_output(result, fill_value=0)
def _apply_to_column_groupbys(self, func):
""" return a pass thru """
return func(self)
def pct_change(self, periods=1, fill_method="pad", limit=None, freq=None):
"""Calculate pct_change of each value to previous entry in group"""
# TODO: Remove this conditional when #23918 is fixed
if freq:
return self.apply(
lambda x: x.pct_change(
periods=periods, fill_method=fill_method, limit=limit, freq=freq
)
)
if fill_method is None: # GH30463
fill_method = "pad"
limit = 0
filled = getattr(self, fill_method)(limit=limit)
fill_grp = filled.groupby(self.grouper.codes)
shifted = fill_grp.shift(periods=periods, freq=freq)
return (filled / shifted) - 1
@pin_whitelisted_properties(DataFrame, base.dataframe_apply_whitelist)
class DataFrameGroupBy(GroupBy):
_apply_whitelist = base.dataframe_apply_whitelist
_agg_see_also_doc = dedent(
"""
See Also
--------
pandas.DataFrame.groupby.apply
pandas.DataFrame.groupby.transform
pandas.DataFrame.aggregate
"""
)
_agg_examples_doc = dedent(
"""
Examples
--------
>>> df = pd.DataFrame({'A': [1, 1, 2, 2],
... 'B': [1, 2, 3, 4],
... 'C': np.random.randn(4)})
>>> df
A B C
0 1 1 0.362838
1 1 2 0.227877
2 2 3 1.267767
3 2 4 -0.562860
The aggregation is for each column.
>>> df.groupby('A').agg('min')
B C
A
1 1 0.227877
2 3 -0.562860
Multiple aggregations
>>> df.groupby('A').agg(['min', 'max'])
B C
min max min max
A
1 1 2 0.227877 0.362838
2 3 4 -0.562860 1.267767
Select a column for aggregation
>>> df.groupby('A').B.agg(['min', 'max'])
min max
A
1 1 2
2 3 4
Different aggregations per column
>>> df.groupby('A').agg({'B': ['min', 'max'], 'C': 'sum'})
B C
min max sum
A
1 1 2 0.590716
2 3 4 0.704907
To control the output names with different aggregations per column,
pandas supports "named aggregation"
>>> df.groupby("A").agg(
... b_min=pd.NamedAgg(column="B", aggfunc="min"),
... c_sum=pd.NamedAgg(column="C", aggfunc="sum"))
b_min c_sum
A
1 1 -1.956929
2 3 -0.322183
- The keywords are the *output* column names
- The values are tuples whose first element is the column to select
and the second element is the aggregation to apply to that column.
Pandas provides the ``pandas.NamedAgg`` namedtuple with the fields
``['column', 'aggfunc']`` to make it clearer what the arguments are.
As usual, the aggregation can be a callable or a string alias.
See :ref:`groupby.aggregate.named` for more.
"""
)
@Substitution(
see_also=_agg_see_also_doc,
examples=_agg_examples_doc,
versionadded="",
klass="DataFrame",
axis="",
)
@Appender(_shared_docs["aggregate"])
def aggregate(self, func=None, *args, **kwargs):
relabeling = func is None and _is_multi_agg_with_relabel(**kwargs)
if relabeling:
func, columns, order = _normalize_keyword_aggregation(kwargs)
kwargs = {}
elif isinstance(func, list) and len(func) > len(set(func)):
# GH 28426 will raise error if duplicated function names are used and
# there is no reassigned name
raise SpecificationError(
"Function names must be unique if there is no new column "
"names assigned"
)
elif func is None:
# nicer error message
raise TypeError("Must provide 'func' or tuples of '(column, aggfunc).")
func = _maybe_mangle_lambdas(func)
result, how = self._aggregate(func, *args, **kwargs)
if how is None:
return result
if result is None:
# grouper specific aggregations
if self.grouper.nkeys > 1:
return self._python_agg_general(func, *args, **kwargs)
elif args or kwargs:
result = self._aggregate_frame(func, *args, **kwargs)
elif self.axis == 1:
# _aggregate_multiple_funcs does not allow self.axis == 1
result = self._aggregate_frame(func)
else:
# try to treat as if we are passing a list
try:
result = self._aggregate_multiple_funcs([func], _axis=self.axis)
except ValueError as err:
if "no results" not in str(err):
# raised directly by _aggregate_multiple_funcs
raise
result = self._aggregate_frame(func)
else:
result.columns = Index(
result.columns.levels[0], name=self._selected_obj.columns.name
)
if not self.as_index:
self._insert_inaxis_grouper_inplace(result)
result.index = np.arange(len(result))
if relabeling:
# used reordered index of columns
result = result.iloc[:, order]
result.columns = columns
return result._convert(datetime=True)
agg = aggregate
def _iterate_slices(self) -> Iterable[Series]:
obj = self._selected_obj
if self.axis == 1:
obj = obj.T
if isinstance(obj, Series) and obj.name not in self.exclusions:
# Occurs when doing DataFrameGroupBy(...)["X"]
yield obj
else:
for label, values in obj.items():
if label in self.exclusions:
continue
yield values
def _cython_agg_general(
self, how: str, alt=None, numeric_only: bool = True, min_count: int = -1
) -> DataFrame:
agg_blocks, agg_items = self._cython_agg_blocks(
how, alt=alt, numeric_only=numeric_only, min_count=min_count
)
return self._wrap_agged_blocks(agg_blocks, items=agg_items)
def _cython_agg_blocks(
self, how: str, alt=None, numeric_only: bool = True, min_count: int = -1
) -> "Tuple[List[Block], Index]":
# TODO: the actual managing of mgr_locs is a PITA
# here, it should happen via BlockManager.combine
data: BlockManager = self._get_data_to_aggregate()
if numeric_only:
data = data.get_numeric_data(copy=False)
agg_blocks: List[Block] = []
new_items: List[np.ndarray] = []
deleted_items: List[np.ndarray] = []
no_result = object()
for block in data.blocks:
# Avoid inheriting result from earlier in the loop
result = no_result
locs = block.mgr_locs.as_array
try:
result, _ = self.grouper.aggregate(
block.values, how, axis=1, min_count=min_count
)
except NotImplementedError:
# generally if we have numeric_only=False
# and non-applicable functions
# try to python agg
if alt is None:
# we cannot perform the operation
# in an alternate way, exclude the block
assert how == "ohlc"
deleted_items.append(locs)
continue
# call our grouper again with only this block
obj = self.obj[data.items[locs]]
if obj.shape[1] == 1:
# Avoid call to self.values that can occur in DataFrame
# reductions; see GH#28949
obj = obj.iloc[:, 0]
s = get_groupby(obj, self.grouper)
try:
result = s.aggregate(lambda x: alt(x, axis=self.axis))
except TypeError:
# we may have an exception in trying to aggregate
# continue and exclude the block
deleted_items.append(locs)
continue
else:
result = cast(DataFrame, result)
# unwrap DataFrame to get array
assert len(result._data.blocks) == 1
result = result._data.blocks[0].values
if isinstance(result, np.ndarray) and result.ndim == 1:
result = result.reshape(1, -1)
finally:
assert not isinstance(result, DataFrame)
if result is not no_result:
# see if we can cast the block back to the original dtype
result = maybe_downcast_numeric(result, block.dtype)
if block.is_extension and isinstance(result, np.ndarray):
# e.g. block.values was an IntegerArray
# (1, N) case can occur if block.values was Categorical
# and result is ndarray[object]
assert result.ndim == 1 or result.shape[0] == 1
try:
# Cast back if feasible
result = type(block.values)._from_sequence(
result.ravel(), dtype=block.values.dtype
)
except ValueError:
# reshape to be valid for non-Extension Block
result = result.reshape(1, -1)
agg_block: Block = block.make_block(result)
new_items.append(locs)
agg_blocks.append(agg_block)
if not agg_blocks:
raise DataError("No numeric types to aggregate")
# reset the locs in the blocks to correspond to our
# current ordering
indexer = np.concatenate(new_items)
agg_items = data.items.take(np.sort(indexer))
if deleted_items:
# we need to adjust the indexer to account for the
# items we have removed
# really should be done in internals :<
deleted = np.concatenate(deleted_items)
ai = np.arange(len(data))
mask = np.zeros(len(data))
mask[deleted] = 1
indexer = (ai - mask.cumsum())[indexer]
offset = 0
for blk in agg_blocks:
loc = len(blk.mgr_locs)
blk.mgr_locs = indexer[offset : (offset + loc)]
offset += loc
return agg_blocks, agg_items
def _aggregate_frame(self, func, *args, **kwargs) -> DataFrame:
if self.grouper.nkeys != 1:
raise AssertionError("Number of keys must be 1")
axis = self.axis
obj = self._obj_with_exclusions
result: OrderedDict = OrderedDict()
if axis != obj._info_axis_number:
for name, data in self:
fres = func(data, *args, **kwargs)
result[name] = fres
else:
for name in self.indices:
data = self.get_group(name, obj=obj)
fres = func(data, *args, **kwargs)
result[name] = fres
return self._wrap_frame_output(result, obj)
def _aggregate_item_by_item(self, func, *args, **kwargs) -> DataFrame:
# only for axis==0
obj = self._obj_with_exclusions
result: OrderedDict = OrderedDict()
cannot_agg = []
for item in obj:
data = obj[item]
colg = SeriesGroupBy(data, selection=item, grouper=self.grouper)
cast = self._transform_should_cast(func)
try:
result[item] = colg.aggregate(func, *args, **kwargs)
except ValueError as err:
if "Must produce aggregated value" in str(err):
# raised in _aggregate_named, handle at higher level
# see test_apply_with_mutated_index
raise
# otherwise we get here from an AttributeError in _make_wrapper
cannot_agg.append(item)
continue
else:
if cast:
result[item] = self._try_cast(result[item], data)
result_columns = obj.columns
if cannot_agg:
result_columns = result_columns.drop(cannot_agg)
return DataFrame(result, columns=result_columns)
def _wrap_applied_output(self, keys, values, not_indexed_same=False):
if len(keys) == 0:
return DataFrame(index=keys)
key_names = self.grouper.names
# GH12824.
def first_not_none(values):
try:
return next(com.not_none(*values))
except StopIteration:
return None
v = first_not_none(values)
if v is None:
# GH9684. If all values are None, then this will throw an error.
# We'd prefer it return an empty dataframe.
return DataFrame()
elif isinstance(v, DataFrame):
return self._concat_objects(keys, values, not_indexed_same=not_indexed_same)
elif self.grouper.groupings is not None:
if len(self.grouper.groupings) > 1:
key_index = self.grouper.result_index
else:
ping = self.grouper.groupings[0]
if len(keys) == ping.ngroups:
key_index = ping.group_index
key_index.name = key_names[0]
key_lookup = Index(keys)
indexer = key_lookup.get_indexer(key_index)
# reorder the values
values = [values[i] for i in indexer]
else:
key_index = Index(keys, name=key_names[0])
# don't use the key indexer
if not self.as_index:
key_index = None
# make Nones an empty object
v = first_not_none(values)
if v is None:
return DataFrame()
elif isinstance(v, NDFrame):
# this is to silence a DeprecationWarning
# TODO: Remove when default dtype of empty Series is object
kwargs = v._construct_axes_dict()
if v._constructor is Series:
backup = create_series_with_explicit_dtype(
**kwargs, dtype_if_empty=object
)
else:
backup = v._constructor(**kwargs)
values = [x if (x is not None) else backup for x in values]
v = values[0]
if isinstance(v, (np.ndarray, Index, Series)):
if isinstance(v, Series):
applied_index = self._selected_obj._get_axis(self.axis)
all_indexed_same = all_indexes_same([x.index for x in values])
singular_series = len(values) == 1 and applied_index.nlevels == 1
# GH3596
# provide a reduction (Frame -> Series) if groups are
# unique
if self.squeeze:
# assign the name to this series
if singular_series:
values[0].name = keys[0]
# GH2893
# we have series in the values array, we want to
# produce a series:
# if any of the sub-series are not indexed the same
# OR we don't have a multi-index and we have only a
# single values
return self._concat_objects(
keys, values, not_indexed_same=not_indexed_same
)
# still a series
# path added as of GH 5545
elif all_indexed_same:
from pandas.core.reshape.concat import concat
return concat(values)
if not all_indexed_same:
# GH 8467
return self._concat_objects(keys, values, not_indexed_same=True)
if self.axis == 0 and isinstance(v, ABCSeries):
# GH6124 if the list of Series have a consistent name,
# then propagate that name to the result.
index = v.index.copy()
if index.name is None:
# Only propagate the series name to the result
# if all series have a consistent name. If the
# series do not have a consistent name, do
# nothing.
names = {v.name for v in values}
if len(names) == 1:
index.name = list(names)[0]
# normally use vstack as its faster than concat
# and if we have mi-columns
if (
isinstance(v.index, MultiIndex)
or key_index is None
or isinstance(key_index, MultiIndex)
):
stacked_values = np.vstack([np.asarray(v) for v in values])
result = DataFrame(
stacked_values, index=key_index, columns=index
)
else:
# GH5788 instead of stacking; concat gets the
# dtypes correct
from pandas.core.reshape.concat import concat
result = concat(
values,
keys=key_index,
names=key_index.names,
axis=self.axis,
).unstack()
result.columns = index
elif isinstance(v, ABCSeries):
stacked_values = np.vstack([np.asarray(v) for v in values])
result = DataFrame(
stacked_values.T, index=v.index, columns=key_index
)
else:
# GH#1738: values is list of arrays of unequal lengths
# fall through to the outer else clause
# TODO: sure this is right? we used to do this
# after raising AttributeError above
return Series(values, index=key_index, name=self._selection_name)
# if we have date/time like in the original, then coerce dates
# as we are stacking can easily have object dtypes here
so = self._selected_obj
if so.ndim == 2 and so.dtypes.apply(needs_i8_conversion).any():
result = _recast_datetimelike_result(result)
else:
result = result._convert(datetime=True)
return self._reindex_output(result)
# values are not series or array-like but scalars
else:
# only coerce dates if we find at least 1 datetime
should_coerce = any(isinstance(x, Timestamp) for x in values)
# self._selection_name not passed through to Series as the
# result should not take the name of original selection
# of columns
return Series(values, index=key_index)._convert(
datetime=True, coerce=should_coerce
)
else:
# Handle cases like BinGrouper
return self._concat_objects(keys, values, not_indexed_same=not_indexed_same)
def _transform_general(self, func, *args, **kwargs):
from pandas.core.reshape.concat import concat
applied = []
obj = self._obj_with_exclusions
gen = self.grouper.get_iterator(obj, axis=self.axis)
fast_path, slow_path = self._define_paths(func, *args, **kwargs)
path = None
for name, group in gen:
object.__setattr__(group, "name", name)
if path is None:
# Try slow path and fast path.
try:
path, res = self._choose_path(fast_path, slow_path, group)
except TypeError:
return self._transform_item_by_item(obj, fast_path)
except ValueError:
msg = "transform must return a scalar value for each group"
raise ValueError(msg)
else:
res = path(group)
if isinstance(res, Series):
# we need to broadcast across the
# other dimension; this will preserve dtypes
# GH14457
if not np.prod(group.shape):
continue
elif res.index.is_(obj.index):
r = concat([res] * len(group.columns), axis=1)
r.columns = group.columns
r.index = group.index
else:
r = DataFrame(
np.concatenate([res.values] * len(group.index)).reshape(
group.shape
),
columns=group.columns,
index=group.index,
)
applied.append(r)
else:
applied.append(res)
concat_index = obj.columns if self.axis == 0 else obj.index
other_axis = 1 if self.axis == 0 else 0 # switches between 0 & 1
concatenated = concat(applied, axis=self.axis, verify_integrity=False)
concatenated = concatenated.reindex(concat_index, axis=other_axis, copy=False)
return self._set_result_index_ordered(concatenated)
@Substitution(klass="DataFrame", selected="")
@Appender(_transform_template)
def transform(self, func, *args, **kwargs):
# optimized transforms
func = self._get_cython_func(func) or func
if not isinstance(func, str):
return self._transform_general(func, *args, **kwargs)
elif func not in base.transform_kernel_whitelist:
msg = f"'{func}' is not a valid function name for transform(name)"
raise ValueError(msg)
elif func in base.cythonized_kernels:
# cythonized transformation or canned "reduction+broadcast"
return getattr(self, func)(*args, **kwargs)
# If func is a reduction, we need to broadcast the
# result to the whole group. Compute func result
# and deal with possible broadcasting below.
result = getattr(self, func)(*args, **kwargs)
# a reduction transform
if not isinstance(result, DataFrame):
return self._transform_general(func, *args, **kwargs)
obj = self._obj_with_exclusions
# nuisance columns
if not result.columns.equals(obj.columns):
return self._transform_general(func, *args, **kwargs)
return self._transform_fast(result, func)
def _transform_fast(self, result: DataFrame, func_nm: str) -> DataFrame:
"""
Fast transform path for aggregations
"""
# if there were groups with no observations (Categorical only?)
# try casting data to original dtype
cast = self._transform_should_cast(func_nm)
obj = self._obj_with_exclusions
# for each col, reshape to to size of original frame
# by take operation
ids, _, ngroup = self.grouper.group_info
output = []
for i, _ in enumerate(result.columns):
res = algorithms.take_1d(result.iloc[:, i].values, ids)
# TODO: we have no test cases that get here with EA dtypes;
# try_cast may not be needed if EAs never get here
if cast:
res = self._try_cast(res, obj.iloc[:, i])
output.append(res)
return DataFrame._from_arrays(output, columns=result.columns, index=obj.index)
def _define_paths(self, func, *args, **kwargs):
if isinstance(func, str):
fast_path = lambda group: getattr(group, func)(*args, **kwargs)
slow_path = lambda group: group.apply(
lambda x: getattr(x, func)(*args, **kwargs), axis=self.axis
)
else:
fast_path = lambda group: func(group, *args, **kwargs)
slow_path = lambda group: group.apply(
lambda x: func(x, *args, **kwargs), axis=self.axis
)
return fast_path, slow_path
def _choose_path(self, fast_path: Callable, slow_path: Callable, group: DataFrame):
path = slow_path
res = slow_path(group)
# if we make it here, test if we can use the fast path
try:
res_fast = fast_path(group)
except AssertionError:
raise
except Exception:
# GH#29631 For user-defined function, we cant predict what may be
# raised; see test_transform.test_transform_fastpath_raises
return path, res
# verify fast path does not change columns (and names), otherwise
# its results cannot be joined with those of the slow path
if not isinstance(res_fast, DataFrame):
return path, res
if not res_fast.columns.equals(group.columns):
return path, res
if res_fast.equals(res):
path = fast_path
return path, res
def _transform_item_by_item(self, obj: DataFrame, wrapper) -> DataFrame:
# iterate through columns
output = {}
inds = []
for i, col in enumerate(obj):
try:
output[col] = self[col].transform(wrapper)
except TypeError:
# e.g. trying to call nanmean with string values
pass
else:
inds.append(i)
if len(output) == 0:
raise TypeError("Transform function invalid for data types")
columns = obj.columns
if len(output) < len(obj.columns):
columns = columns.take(inds)
return DataFrame(output, index=obj.index, columns=columns)
def filter(self, func, dropna=True, *args, **kwargs):
"""
Return a copy of a DataFrame excluding elements from groups that
do not satisfy the boolean criterion specified by func.
Parameters
----------
f : function
Function to apply to each subframe. Should return True or False.
dropna : Drop groups that do not pass the filter. True by default;
If False, groups that evaluate False are filled with NaNs.
Returns
-------
filtered : DataFrame
Notes
-----
Each subframe is endowed the attribute 'name' in case you need to know
which group you are working on.
Examples
--------
>>> df = pd.DataFrame({'A' : ['foo', 'bar', 'foo', 'bar',
... 'foo', 'bar'],
... 'B' : [1, 2, 3, 4, 5, 6],
... 'C' : [2.0, 5., 8., 1., 2., 9.]})
>>> grouped = df.groupby('A')
>>> grouped.filter(lambda x: x['B'].mean() > 3.)
A B C
1 bar 2 5.0
3 bar 4 1.0
5 bar 6 9.0
"""
indices = []
obj = self._selected_obj
gen = self.grouper.get_iterator(obj, axis=self.axis)
for name, group in gen:
object.__setattr__(group, "name", name)
res = func(group, *args, **kwargs)
try:
res = res.squeeze()
except AttributeError: # allow e.g., scalars and frames to pass
pass
# interpret the result of the filter
if is_bool(res) or (is_scalar(res) and isna(res)):
if res and notna(res):
indices.append(self._get_index(name))
else:
# non scalars aren't allowed
raise TypeError(
f"filter function returned a {type(res).__name__}, "
"but expected a scalar bool"
)
return self._apply_filter(indices, dropna)
def _gotitem(self, key, ndim: int, subset=None):
"""
sub-classes to define
return a sliced object
Parameters
----------
key : string / list of selections
ndim : 1,2
requested ndim of result
subset : object, default None
subset to act on
"""
if ndim == 2:
if subset is None:
subset = self.obj
return DataFrameGroupBy(
subset,
self.grouper,
selection=key,
grouper=self.grouper,
exclusions=self.exclusions,
as_index=self.as_index,
observed=self.observed,
)
elif ndim == 1:
if subset is None:
subset = self.obj[key]
return SeriesGroupBy(
subset, selection=key, grouper=self.grouper, observed=self.observed
)
raise AssertionError("invalid ndim for _gotitem")
def _wrap_frame_output(self, result, obj) -> DataFrame:
result_index = self.grouper.levels[0]
if self.axis == 0:
return DataFrame(result, index=obj.columns, columns=result_index).T
else:
return DataFrame(result, index=obj.index, columns=result_index)
def _get_data_to_aggregate(self) -> BlockManager:
obj = self._obj_with_exclusions
if self.axis == 1:
return obj.T._data
else:
return obj._data
def _insert_inaxis_grouper_inplace(self, result):
# zip in reverse so we can always insert at loc 0
izip = zip(
*map(
reversed,
(
self.grouper.names,
self.grouper.get_group_levels(),
[grp.in_axis for grp in self.grouper.groupings],
),
)
)
for name, lev, in_axis in izip:
if in_axis:
result.insert(0, name, lev)
def _wrap_aggregated_output(
self, output: Mapping[base.OutputKey, Union[Series, np.ndarray]]
) -> DataFrame:
"""
Wraps the output of DataFrameGroupBy aggregations into the expected result.
Parameters
----------
output : Mapping[base.OutputKey, Union[Series, np.ndarray]]
Data to wrap.
Returns
-------
DataFrame
"""
indexed_output = {key.position: val for key, val in output.items()}
columns = Index(key.label for key in output)
result = DataFrame(indexed_output)
result.columns = columns
if not self.as_index:
self._insert_inaxis_grouper_inplace(result)
result = result._consolidate()
else:
index = self.grouper.result_index
result.index = index
if self.axis == 1:
result = result.T
return self._reindex_output(result)._convert(datetime=True)
def _wrap_transformed_output(
self, output: Mapping[base.OutputKey, Union[Series, np.ndarray]]
) -> DataFrame:
"""
Wraps the output of DataFrameGroupBy transformations into the expected result.
Parameters
----------
output : Mapping[base.OutputKey, Union[Series, np.ndarray]]
Data to wrap.
Returns
-------
DataFrame
"""
indexed_output = {key.position: val for key, val in output.items()}
columns = Index(key.label for key in output)
result = DataFrame(indexed_output)
result.columns = columns
result.index = self.obj.index
return result
def _wrap_agged_blocks(self, blocks: "Sequence[Block]", items: Index) -> DataFrame:
if not self.as_index:
index = np.arange(blocks[0].values.shape[-1])
mgr = BlockManager(blocks, axes=[items, index])
result = DataFrame(mgr)
self._insert_inaxis_grouper_inplace(result)
result = result._consolidate()
else:
index = self.grouper.result_index
mgr = BlockManager(blocks, axes=[items, index])
result = DataFrame(mgr)
if self.axis == 1:
result = result.T
return self._reindex_output(result)._convert(datetime=True)
def _iterate_column_groupbys(self):
for i, colname in enumerate(self._selected_obj.columns):
yield colname, SeriesGroupBy(
self._selected_obj.iloc[:, i],
selection=colname,
grouper=self.grouper,
exclusions=self.exclusions,
)
def _apply_to_column_groupbys(self, func):
from pandas.core.reshape.concat import concat
return concat(
(func(col_groupby) for _, col_groupby in self._iterate_column_groupbys()),
keys=self._selected_obj.columns,
axis=1,
)
def count(self):
"""
Compute count of group, excluding missing values.
Returns
-------
DataFrame
Count of values within each group.
"""
data = self._get_data_to_aggregate()
ids, _, ngroups = self.grouper.group_info
mask = ids != -1
vals = (
(mask & ~_isna_ndarraylike(np.atleast_2d(blk.get_values())))
for blk in data.blocks
)
locs = (blk.mgr_locs for blk in data.blocks)
counted = (
lib.count_level_2d(x, labels=ids, max_bin=ngroups, axis=1) for x in vals
)
blocks = [make_block(val, placement=loc) for val, loc in zip(counted, locs)]
return self._wrap_agged_blocks(blocks, items=data.items)
def nunique(self, dropna: bool = True):
"""
Return DataFrame with number of distinct observations per group for
each column.
Parameters
----------
dropna : bool, default True
Don't include NaN in the counts.
Returns
-------
nunique: DataFrame
Examples
--------
>>> df = pd.DataFrame({'id': ['spam', 'egg', 'egg', 'spam',
... 'ham', 'ham'],
... 'value1': [1, 5, 5, 2, 5, 5],
... 'value2': list('abbaxy')})
>>> df
id value1 value2
0 spam 1 a
1 egg 5 b
2 egg 5 b
3 spam 2 a
4 ham 5 x
5 ham 5 y
>>> df.groupby('id').nunique()
id value1 value2
id
egg 1 1 1
ham 1 1 2
spam 1 2 1
Check for rows with the same id but conflicting values:
>>> df.groupby('id').filter(lambda g: (g.nunique() > 1).any())
id value1 value2
0 spam 1 a
3 spam 2 a
4 ham 5 x
5 ham 5 y
"""
obj = self._selected_obj
def groupby_series(obj, col=None):
return SeriesGroupBy(obj, selection=col, grouper=self.grouper).nunique(
dropna=dropna
)
if isinstance(obj, Series):
results = groupby_series(obj)
else:
# TODO: this is duplicative of how GroupBy naturally works
# Try to consolidate with normal wrapping functions
from pandas.core.reshape.concat import concat
axis_number = obj._get_axis_number(self.axis)
other_axis = int(not axis_number)
if axis_number == 0:
iter_func = obj.items
else:
iter_func = obj.iterrows
results = [groupby_series(content, label) for label, content in iter_func()]
results = concat(results, axis=1)
if axis_number == 1:
results = results.T
results._get_axis(other_axis).names = obj._get_axis(other_axis).names
if not self.as_index:
results.index = ibase.default_index(len(results))
return results
boxplot = boxplot_frame_groupby
def _is_multi_agg_with_relabel(**kwargs) -> bool:
"""
Check whether kwargs passed to .agg look like multi-agg with relabeling.
Parameters
----------
**kwargs : dict
Returns
-------
bool
Examples
--------
>>> _is_multi_agg_with_relabel(a='max')
False
>>> _is_multi_agg_with_relabel(a_max=('a', 'max'),
... a_min=('a', 'min'))
True
>>> _is_multi_agg_with_relabel()
False
"""
return all(isinstance(v, tuple) and len(v) == 2 for v in kwargs.values()) and (
len(kwargs) > 0
)
def _normalize_keyword_aggregation(kwargs):
"""
Normalize user-provided "named aggregation" kwargs.
Transforms from the new ``Mapping[str, NamedAgg]`` style kwargs
to the old OrderedDict[str, List[scalar]]].
Parameters
----------
kwargs : dict
Returns
-------
aggspec : dict
The transformed kwargs.
columns : List[str]
The user-provided keys.
col_idx_order : List[int]
List of columns indices.
Examples
--------
>>> _normalize_keyword_aggregation({'output': ('input', 'sum')})
(OrderedDict([('input', ['sum'])]), ('output',), [('input', 'sum')])
"""
# Normalize the aggregation functions as Mapping[column, List[func]],
# process normally, then fixup the names.
# TODO: aggspec type: typing.OrderedDict[str, List[AggScalar]]
# May be hitting https://github.com/python/mypy/issues/5958
# saying it doesn't have an attribute __name__
aggspec = defaultdict(list)
order = []
columns, pairs = list(zip(*kwargs.items()))
for name, (column, aggfunc) in zip(columns, pairs):
aggspec[column].append(aggfunc)
order.append((column, com.get_callable_name(aggfunc) or aggfunc))
# uniquify aggfunc name if duplicated in order list
uniquified_order = _make_unique(order)
# GH 25719, due to aggspec will change the order of assigned columns in aggregation
# uniquified_aggspec will store uniquified order list and will compare it with order
# based on index
aggspec_order = [
(column, com.get_callable_name(aggfunc) or aggfunc)
for column, aggfuncs in aggspec.items()
for aggfunc in aggfuncs
]
uniquified_aggspec = _make_unique(aggspec_order)
# get the new indice of columns by comparison
col_idx_order = Index(uniquified_aggspec).get_indexer(uniquified_order)
return aggspec, columns, col_idx_order
def _make_unique(seq):
"""Uniquify aggfunc name of the pairs in the order list
Examples:
--------
>>> _make_unique([('a', '<lambda>'), ('a', '<lambda>'), ('b', '<lambda>')])
[('a', '<lambda>_0'), ('a', '<lambda>_1'), ('b', '<lambda>')]
"""
return [
(pair[0], "_".join([pair[1], str(seq[:i].count(pair))]))
if seq.count(pair) > 1
else pair
for i, pair in enumerate(seq)
]
# TODO: Can't use, because mypy doesn't like us setting __name__
# error: "partial[Any]" has no attribute "__name__"
# the type is:
# typing.Sequence[Callable[..., ScalarResult]]
# -> typing.Sequence[Callable[..., ScalarResult]]:
def _managle_lambda_list(aggfuncs: Sequence[Any]) -> Sequence[Any]:
"""
Possibly mangle a list of aggfuncs.
Parameters
----------
aggfuncs : Sequence
Returns
-------
mangled: list-like
A new AggSpec sequence, where lambdas have been converted
to have unique names.
Notes
-----
If just one aggfunc is passed, the name will not be mangled.
"""
if len(aggfuncs) <= 1:
# don't mangle for .agg([lambda x: .])
return aggfuncs
i = 0
mangled_aggfuncs = []
for aggfunc in aggfuncs:
if com.get_callable_name(aggfunc) == "<lambda>":
aggfunc = partial(aggfunc)
aggfunc.__name__ = f"<lambda_{i}>"
i += 1
mangled_aggfuncs.append(aggfunc)
return mangled_aggfuncs
def _maybe_mangle_lambdas(agg_spec: Any) -> Any:
"""
Make new lambdas with unique names.
Parameters
----------
agg_spec : Any
An argument to GroupBy.agg.
Non-dict-like `agg_spec` are pass through as is.
For dict-like `agg_spec` a new spec is returned
with name-mangled lambdas.
Returns
-------
mangled : Any
Same type as the input.
Examples
--------
>>> _maybe_mangle_lambdas('sum')
'sum'
>>> _maybe_mangle_lambdas([lambda: 1, lambda: 2]) # doctest: +SKIP
[<function __main__.<lambda_0>,
<function pandas...._make_lambda.<locals>.f(*args, **kwargs)>]
"""
is_dict = is_dict_like(agg_spec)
if not (is_dict or is_list_like(agg_spec)):
return agg_spec
mangled_aggspec = type(agg_spec)() # dict or OrderdDict
if is_dict:
for key, aggfuncs in agg_spec.items():
if is_list_like(aggfuncs) and not is_dict_like(aggfuncs):
mangled_aggfuncs = _managle_lambda_list(aggfuncs)
else:
mangled_aggfuncs = aggfuncs
mangled_aggspec[key] = mangled_aggfuncs
else:
mangled_aggspec = _managle_lambda_list(agg_spec)
return mangled_aggspec
def _recast_datetimelike_result(result: DataFrame) -> DataFrame:
"""
If we have date/time like in the original, then coerce dates
as we are stacking can easily have object dtypes here.
Parameters
----------
result : DataFrame
Returns
-------
DataFrame
Notes
-----
- Assumes Groupby._selected_obj has ndim==2 and at least one
datetimelike column
"""
result = result.copy()
obj_cols = [
idx
for idx in range(len(result.columns))
if is_object_dtype(result.dtypes.iloc[idx])
]
# See GH#26285
for n in obj_cols:
converted = maybe_convert_objects(
result.iloc[:, n].values, convert_numeric=False
)
result.iloc[:, n] = converted
return result
| BugsInPy/BugsInPy/temp/projects/pandas/bug-103-fixed/pandas/pandas/core/groupby/generic.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-103-buggy/pandas/pandas/core/groupby/generic.py |
pandas-bug-9 | import operator
from shutil import get_terminal_size
from typing import Dict, Hashable, List, Type, Union, cast
from warnings import warn
import numpy as np
from pandas._config import get_option
from pandas._libs import algos as libalgos, hashtable as htable
from pandas._typing import ArrayLike, Dtype, Ordered, Scalar
from pandas.util._decorators import cache_readonly, deprecate_kwarg, doc
from pandas.util._validators import validate_bool_kwarg, validate_fillna_kwargs
from pandas.core.dtypes.cast import (
coerce_indexer_dtype,
maybe_cast_to_extension_array,
maybe_infer_to_datetimelike,
)
from pandas.core.dtypes.common import (
ensure_int64,
ensure_object,
is_categorical_dtype,
is_datetime64_dtype,
is_dict_like,
is_dtype_equal,
is_extension_array_dtype,
is_integer_dtype,
is_iterator,
is_list_like,
is_object_dtype,
is_scalar,
is_sequence,
is_timedelta64_dtype,
needs_i8_conversion,
)
from pandas.core.dtypes.dtypes import CategoricalDtype
from pandas.core.dtypes.generic import ABCIndexClass, ABCSeries
from pandas.core.dtypes.inference import is_hashable
from pandas.core.dtypes.missing import isna, notna
from pandas.core import ops
from pandas.core.accessor import PandasDelegate, delegate_names
import pandas.core.algorithms as algorithms
from pandas.core.algorithms import _get_data_algo, factorize, take_1d, unique1d
from pandas.core.array_algos.transforms import shift
from pandas.core.arrays._mixins import _T, NDArrayBackedExtensionArray
from pandas.core.base import NoNewAttributesMixin, PandasObject, _shared_docs
import pandas.core.common as com
from pandas.core.construction import array, extract_array, sanitize_array
from pandas.core.indexers import check_array_indexer, deprecate_ndim_indexing
from pandas.core.missing import interpolate_2d
from pandas.core.ops.common import unpack_zerodim_and_defer
from pandas.core.sorting import nargsort
from pandas.io.formats import console
def _cat_compare_op(op):
opname = f"__{op.__name__}__"
@unpack_zerodim_and_defer(opname)
def func(self, other):
if is_list_like(other) and len(other) != len(self):
# TODO: Could this fail if the categories are listlike objects?
raise ValueError("Lengths must match.")
if not self.ordered:
if opname in ["__lt__", "__gt__", "__le__", "__ge__"]:
raise TypeError(
"Unordered Categoricals can only compare equality or not"
)
if isinstance(other, Categorical):
# Two Categoricals can only be be compared if the categories are
# the same (maybe up to ordering, depending on ordered)
msg = "Categoricals can only be compared if 'categories' are the same."
if len(self.categories) != len(other.categories):
raise TypeError(msg + " Categories are different lengths")
elif self.ordered and not (self.categories == other.categories).all():
raise TypeError(msg)
elif not set(self.categories) == set(other.categories):
raise TypeError(msg)
if not (self.ordered == other.ordered):
raise TypeError(
"Categoricals can only be compared if 'ordered' is the same"
)
if not self.ordered and not self.categories.equals(other.categories):
# both unordered and different order
other_codes = _get_codes_for_values(other, self.categories)
else:
other_codes = other._codes
f = getattr(self._codes, opname)
ret = f(other_codes)
mask = (self._codes == -1) | (other_codes == -1)
if mask.any():
# In other series, the leads to False, so do that here too
if opname == "__ne__":
ret[(self._codes == -1) & (other_codes == -1)] = True
else:
ret[mask] = False
return ret
if is_scalar(other):
if other in self.categories:
i = self.categories.get_loc(other)
ret = getattr(self._codes, opname)(i)
if opname not in {"__eq__", "__ge__", "__gt__"}:
# check for NaN needed if we are not equal or larger
mask = self._codes == -1
ret[mask] = False
return ret
else:
if opname == "__eq__":
return np.zeros(len(self), dtype=bool)
elif opname == "__ne__":
return np.ones(len(self), dtype=bool)
else:
raise TypeError(
f"Cannot compare a Categorical for op {opname} with a "
"scalar, which is not a category."
)
else:
# allow categorical vs object dtype array comparisons for equality
# these are only positional comparisons
if opname in ["__eq__", "__ne__"]:
return getattr(np.array(self), opname)(np.array(other))
raise TypeError(
f"Cannot compare a Categorical for op {opname} with "
f"type {type(other)}.\nIf you want to compare values, "
"use 'np.asarray(cat) <op> other'."
)
func.__name__ = opname
return func
def contains(cat, key, container):
"""
Helper for membership check for ``key`` in ``cat``.
This is a helper method for :method:`__contains__`
and :class:`CategoricalIndex.__contains__`.
Returns True if ``key`` is in ``cat.categories`` and the
location of ``key`` in ``categories`` is in ``container``.
Parameters
----------
cat : :class:`Categorical`or :class:`categoricalIndex`
key : a hashable object
The key to check membership for.
container : Container (e.g. list-like or mapping)
The container to check for membership in.
Returns
-------
is_in : bool
True if ``key`` is in ``self.categories`` and location of
``key`` in ``categories`` is in ``container``, else False.
Notes
-----
This method does not check for NaN values. Do that separately
before calling this method.
"""
hash(key)
# get location of key in categories.
# If a KeyError, the key isn't in categories, so logically
# can't be in container either.
try:
loc = cat.categories.get_loc(key)
except (KeyError, TypeError):
return False
# loc is the location of key in categories, but also the *value*
# for key in container. So, `key` may be in categories,
# but still not in `container`. Example ('b' in categories,
# but not in values):
# 'b' in Categorical(['a'], categories=['a', 'b']) # False
if is_scalar(loc):
return loc in container
else:
# if categories is an IntervalIndex, loc is an array.
return any(loc_ in container for loc_ in loc)
class Categorical(NDArrayBackedExtensionArray, PandasObject):
"""
Represent a categorical variable in classic R / S-plus fashion.
`Categoricals` can only take on only a limited, and usually fixed, number
of possible values (`categories`). In contrast to statistical categorical
variables, a `Categorical` might have an order, but numerical operations
(additions, divisions, ...) are not possible.
All values of the `Categorical` are either in `categories` or `np.nan`.
Assigning values outside of `categories` will raise a `ValueError`. Order
is defined by the order of the `categories`, not lexical order of the
values.
Parameters
----------
values : list-like
The values of the categorical. If categories are given, values not in
categories will be replaced with NaN.
categories : Index-like (unique), optional
The unique categories for this categorical. If not given, the
categories are assumed to be the unique values of `values` (sorted, if
possible, otherwise in the order in which they appear).
ordered : bool, default False
Whether or not this categorical is treated as a ordered categorical.
If True, the resulting categorical will be ordered.
An ordered categorical respects, when sorted, the order of its
`categories` attribute (which in turn is the `categories` argument, if
provided).
dtype : CategoricalDtype
An instance of ``CategoricalDtype`` to use for this categorical.
Attributes
----------
categories : Index
The categories of this categorical
codes : ndarray
The codes (integer positions, which point to the categories) of this
categorical, read only.
ordered : bool
Whether or not this Categorical is ordered.
dtype : CategoricalDtype
The instance of ``CategoricalDtype`` storing the ``categories``
and ``ordered``.
Methods
-------
from_codes
__array__
Raises
------
ValueError
If the categories do not validate.
TypeError
If an explicit ``ordered=True`` is given but no `categories` and the
`values` are not sortable.
See Also
--------
CategoricalDtype : Type for categorical data.
CategoricalIndex : An Index with an underlying ``Categorical``.
Notes
-----
See the `user guide
<https://pandas.pydata.org/pandas-docs/stable/user_guide/categorical.html>`_
for more.
Examples
--------
>>> pd.Categorical([1, 2, 3, 1, 2, 3])
[1, 2, 3, 1, 2, 3]
Categories (3, int64): [1, 2, 3]
>>> pd.Categorical(['a', 'b', 'c', 'a', 'b', 'c'])
[a, b, c, a, b, c]
Categories (3, object): [a, b, c]
Ordered `Categoricals` can be sorted according to the custom order
of the categories and can have a min and max value.
>>> c = pd.Categorical(['a', 'b', 'c', 'a', 'b', 'c'], ordered=True,
... categories=['c', 'b', 'a'])
>>> c
[a, b, c, a, b, c]
Categories (3, object): [c < b < a]
>>> c.min()
'c'
"""
# For comparisons, so that numpy uses our implementation if the compare
# ops, which raise
__array_priority__ = 1000
_dtype = CategoricalDtype(ordered=False)
# tolist is not actually deprecated, just suppressed in the __dir__
_deprecations = PandasObject._deprecations | frozenset(["tolist"])
_typ = "categorical"
def __init__(
self, values, categories=None, ordered=None, dtype=None, fastpath=False
):
dtype = CategoricalDtype._from_values_or_dtype(
values, categories, ordered, dtype
)
# At this point, dtype is always a CategoricalDtype, but
# we may have dtype.categories be None, and we need to
# infer categories in a factorization step further below
if fastpath:
self._codes = coerce_indexer_dtype(values, dtype.categories)
self._dtype = self._dtype.update_dtype(dtype)
return
# null_mask indicates missing values we want to exclude from inference.
# This means: only missing values in list-likes (not arrays/ndframes).
null_mask = np.array(False)
# sanitize input
if is_categorical_dtype(values):
if dtype.categories is None:
dtype = CategoricalDtype(values.categories, dtype.ordered)
elif not isinstance(values, (ABCIndexClass, ABCSeries)):
# sanitize_array coerces np.nan to a string under certain versions
# of numpy
values = maybe_infer_to_datetimelike(values, convert_dates=True)
if not isinstance(values, np.ndarray):
values = _convert_to_list_like(values)
# By convention, empty lists result in object dtype:
sanitize_dtype = np.dtype("O") if len(values) == 0 else None
null_mask = isna(values)
if null_mask.any():
values = [values[idx] for idx in np.where(~null_mask)[0]]
values = sanitize_array(values, None, dtype=sanitize_dtype)
if dtype.categories is None:
try:
codes, categories = factorize(values, sort=True)
except TypeError as err:
codes, categories = factorize(values, sort=False)
if dtype.ordered:
# raise, as we don't have a sortable data structure and so
# the user should give us one by specifying categories
raise TypeError(
"'values' is not ordered, please "
"explicitly specify the categories order "
"by passing in a categories argument."
) from err
except ValueError as err:
# FIXME
raise NotImplementedError(
"> 1 ndim Categorical are not supported at this time"
) from err
# we're inferring from values
dtype = CategoricalDtype(categories, dtype.ordered)
elif is_categorical_dtype(values.dtype):
old_codes = (
values._values.codes if isinstance(values, ABCSeries) else values.codes
)
codes = recode_for_categories(
old_codes, values.dtype.categories, dtype.categories
)
else:
codes = _get_codes_for_values(values, dtype.categories)
if null_mask.any():
# Reinsert -1 placeholders for previously removed missing values
full_codes = -np.ones(null_mask.shape, dtype=codes.dtype)
full_codes[~null_mask] = codes
codes = full_codes
self._dtype = self._dtype.update_dtype(dtype)
self._codes = coerce_indexer_dtype(codes, dtype.categories)
@property
def categories(self):
"""
The categories of this categorical.
Setting assigns new values to each category (effectively a rename of
each individual category).
The assigned value has to be a list-like object. All items must be
unique and the number of items in the new categories must be the same
as the number of items in the old categories.
Assigning to `categories` is a inplace operation!
Raises
------
ValueError
If the new categories do not validate as categories or if the
number of new categories is unequal the number of old categories
See Also
--------
rename_categories : Rename categories.
reorder_categories : Reorder categories.
add_categories : Add new categories.
remove_categories : Remove the specified categories.
remove_unused_categories : Remove categories which are not used.
set_categories : Set the categories to the specified ones.
"""
return self.dtype.categories
@categories.setter
def categories(self, categories):
new_dtype = CategoricalDtype(categories, ordered=self.ordered)
if self.dtype.categories is not None and len(self.dtype.categories) != len(
new_dtype.categories
):
raise ValueError(
"new categories need to have the same number of "
"items as the old categories!"
)
self._dtype = new_dtype
@property
def ordered(self) -> Ordered:
"""
Whether the categories have an ordered relationship.
"""
return self.dtype.ordered
@property
def dtype(self) -> CategoricalDtype:
"""
The :class:`~pandas.api.types.CategoricalDtype` for this instance.
"""
return self._dtype
@property
def _constructor(self) -> Type["Categorical"]:
return Categorical
@classmethod
def _from_sequence(cls, scalars, dtype=None, copy=False):
return Categorical(scalars, dtype=dtype)
def _formatter(self, boxed=False):
# Defer to CategoricalFormatter's formatter.
return None
def astype(self, dtype: Dtype, copy: bool = True) -> ArrayLike:
"""
Coerce this type to another dtype
Parameters
----------
dtype : numpy dtype or pandas type
copy : bool, default True
By default, astype always returns a newly allocated object.
If copy is set to False and dtype is categorical, the original
object is returned.
"""
if is_categorical_dtype(dtype):
dtype = cast(Union[str, CategoricalDtype], dtype)
# GH 10696/18593
dtype = self.dtype.update_dtype(dtype)
self = self.copy() if copy else self
if dtype == self.dtype:
return self
return self._set_dtype(dtype)
if is_extension_array_dtype(dtype):
return array(self, dtype=dtype, copy=copy)
if is_integer_dtype(dtype) and self.isna().any():
raise ValueError("Cannot convert float NaN to integer")
return np.array(self, dtype=dtype, copy=copy)
@cache_readonly
def itemsize(self) -> int:
"""
return the size of a single category
"""
return self.categories.itemsize
def tolist(self) -> List[Scalar]:
"""
Return a list of the values.
These are each a scalar type, which is a Python scalar
(for str, int, float) or a pandas scalar
(for Timestamp/Timedelta/Interval/Period)
"""
return list(self)
to_list = tolist
@classmethod
def _from_inferred_categories(
cls, inferred_categories, inferred_codes, dtype, true_values=None
):
"""
Construct a Categorical from inferred values.
For inferred categories (`dtype` is None) the categories are sorted.
For explicit `dtype`, the `inferred_categories` are cast to the
appropriate type.
Parameters
----------
inferred_categories : Index
inferred_codes : Index
dtype : CategoricalDtype or 'category'
true_values : list, optional
If none are provided, the default ones are
"True", "TRUE", and "true."
Returns
-------
Categorical
"""
from pandas import Index, to_numeric, to_datetime, to_timedelta
cats = Index(inferred_categories)
known_categories = (
isinstance(dtype, CategoricalDtype) and dtype.categories is not None
)
if known_categories:
# Convert to a specialized type with `dtype` if specified.
if dtype.categories.is_numeric():
cats = to_numeric(inferred_categories, errors="coerce")
elif is_datetime64_dtype(dtype.categories):
cats = to_datetime(inferred_categories, errors="coerce")
elif is_timedelta64_dtype(dtype.categories):
cats = to_timedelta(inferred_categories, errors="coerce")
elif dtype.categories.is_boolean():
if true_values is None:
true_values = ["True", "TRUE", "true"]
cats = cats.isin(true_values)
if known_categories:
# Recode from observation order to dtype.categories order.
categories = dtype.categories
codes = recode_for_categories(inferred_codes, cats, categories)
elif not cats.is_monotonic_increasing:
# Sort categories and recode for unknown categories.
unsorted = cats.copy()
categories = cats.sort_values()
codes = recode_for_categories(inferred_codes, unsorted, categories)
dtype = CategoricalDtype(categories, ordered=False)
else:
dtype = CategoricalDtype(cats, ordered=False)
codes = inferred_codes
return cls(codes, dtype=dtype, fastpath=True)
@classmethod
def from_codes(cls, codes, categories=None, ordered=None, dtype=None):
"""
Make a Categorical type from codes and categories or dtype.
This constructor is useful if you already have codes and
categories/dtype and so do not need the (computation intensive)
factorization step, which is usually done on the constructor.
If your data does not follow this convention, please use the normal
constructor.
Parameters
----------
codes : array-like of int
An integer array, where each integer points to a category in
categories or dtype.categories, or else is -1 for NaN.
categories : index-like, optional
The categories for the categorical. Items need to be unique.
If the categories are not given here, then they must be provided
in `dtype`.
ordered : bool, optional
Whether or not this categorical is treated as an ordered
categorical. If not given here or in `dtype`, the resulting
categorical will be unordered.
dtype : CategoricalDtype or "category", optional
If :class:`CategoricalDtype`, cannot be used together with
`categories` or `ordered`.
.. versionadded:: 0.24.0
When `dtype` is provided, neither `categories` nor `ordered`
should be provided.
Returns
-------
Categorical
Examples
--------
>>> dtype = pd.CategoricalDtype(['a', 'b'], ordered=True)
>>> pd.Categorical.from_codes(codes=[0, 1, 0, 1], dtype=dtype)
[a, b, a, b]
Categories (2, object): [a < b]
"""
dtype = CategoricalDtype._from_values_or_dtype(
categories=categories, ordered=ordered, dtype=dtype
)
if dtype.categories is None:
msg = (
"The categories must be provided in 'categories' or "
"'dtype'. Both were None."
)
raise ValueError(msg)
if is_extension_array_dtype(codes) and is_integer_dtype(codes):
# Avoid the implicit conversion of Int to object
if isna(codes).any():
raise ValueError("codes cannot contain NA values")
codes = codes.to_numpy(dtype=np.int64)
else:
codes = np.asarray(codes)
if len(codes) and not is_integer_dtype(codes):
raise ValueError("codes need to be array-like integers")
if len(codes) and (codes.max() >= len(dtype.categories) or codes.min() < -1):
raise ValueError("codes need to be between -1 and len(categories)-1")
return cls(codes, dtype=dtype, fastpath=True)
@property
def codes(self) -> np.ndarray:
"""
The category codes of this categorical.
Codes are an array of integers which are the positions of the actual
values in the categories array.
There is no setter, use the other categorical methods and the normal item
setter to change values in the categorical.
Returns
-------
ndarray[int]
A non-writable view of the `codes` array.
"""
v = self._codes.view()
v.flags.writeable = False
return v
def _set_categories(self, categories, fastpath=False):
"""
Sets new categories inplace
Parameters
----------
fastpath : bool, default False
Don't perform validation of the categories for uniqueness or nulls
Examples
--------
>>> c = pd.Categorical(['a', 'b'])
>>> c
[a, b]
Categories (2, object): [a, b]
>>> c._set_categories(pd.Index(['a', 'c']))
>>> c
[a, c]
Categories (2, object): [a, c]
"""
if fastpath:
new_dtype = CategoricalDtype._from_fastpath(categories, self.ordered)
else:
new_dtype = CategoricalDtype(categories, ordered=self.ordered)
if (
not fastpath
and self.dtype.categories is not None
and len(new_dtype.categories) != len(self.dtype.categories)
):
raise ValueError(
"new categories need to have the same number of "
"items than the old categories!"
)
self._dtype = new_dtype
def _set_dtype(self, dtype: CategoricalDtype) -> "Categorical":
"""
Internal method for directly updating the CategoricalDtype
Parameters
----------
dtype : CategoricalDtype
Notes
-----
We don't do any validation here. It's assumed that the dtype is
a (valid) instance of `CategoricalDtype`.
"""
codes = recode_for_categories(self.codes, self.categories, dtype.categories)
return type(self)(codes, dtype=dtype, fastpath=True)
def set_ordered(self, value, inplace=False):
"""
Set the ordered attribute to the boolean value.
Parameters
----------
value : bool
Set whether this categorical is ordered (True) or not (False).
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to the value.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
new_dtype = CategoricalDtype(self.categories, ordered=value)
cat = self if inplace else self.copy()
cat._dtype = new_dtype
if not inplace:
return cat
def as_ordered(self, inplace=False):
"""
Set the Categorical to be ordered.
Parameters
----------
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to True.
Returns
-------
Categorical
Ordered Categorical.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
return self.set_ordered(True, inplace=inplace)
def as_unordered(self, inplace=False):
"""
Set the Categorical to be unordered.
Parameters
----------
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to False.
Returns
-------
Categorical
Unordered Categorical.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
return self.set_ordered(False, inplace=inplace)
def set_categories(self, new_categories, ordered=None, rename=False, inplace=False):
"""
Set the categories to the specified new_categories.
`new_categories` can include new categories (which will result in
unused categories) or remove old categories (which results in values
set to NaN). If `rename==True`, the categories will simple be renamed
(less or more items than in old categories will result in values set to
NaN or in unused categories respectively).
This method can be used to perform more than one action of adding,
removing, and reordering simultaneously and is therefore faster than
performing the individual steps via the more specialised methods.
On the other hand this methods does not do checks (e.g., whether the
old categories are included in the new categories on a reorder), which
can result in surprising changes, for example when using special string
dtypes, which does not considers a S1 string equal to a single char
python string.
Parameters
----------
new_categories : Index-like
The categories in new order.
ordered : bool, default False
Whether or not the categorical is treated as a ordered categorical.
If not given, do not change the ordered information.
rename : bool, default False
Whether or not the new_categories should be considered as a rename
of the old categories or as reordered categories.
inplace : bool, default False
Whether or not to reorder the categories in-place or return a copy
of this categorical with reordered categories.
Returns
-------
Categorical with reordered categories or None if inplace.
Raises
------
ValueError
If new_categories does not validate as categories
See Also
--------
rename_categories : Rename categories.
reorder_categories : Reorder categories.
add_categories : Add new categories.
remove_categories : Remove the specified categories.
remove_unused_categories : Remove categories which are not used.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if ordered is None:
ordered = self.dtype.ordered
new_dtype = CategoricalDtype(new_categories, ordered=ordered)
cat = self if inplace else self.copy()
if rename:
if cat.dtype.categories is not None and len(new_dtype.categories) < len(
cat.dtype.categories
):
# remove all _codes which are larger and set to -1/NaN
cat._codes[cat._codes >= len(new_dtype.categories)] = -1
else:
codes = recode_for_categories(
cat.codes, cat.categories, new_dtype.categories
)
cat._codes = codes
cat._dtype = new_dtype
if not inplace:
return cat
def rename_categories(self, new_categories, inplace=False):
"""
Rename categories.
Parameters
----------
new_categories : list-like, dict-like or callable
New categories which will replace old categories.
* list-like: all items must be unique and the number of items in
the new categories must match the existing number of categories.
* dict-like: specifies a mapping from
old categories to new. Categories not contained in the mapping
are passed through and extra categories in the mapping are
ignored.
* callable : a callable that is called on all items in the old
categories and whose return values comprise the new categories.
.. versionadded:: 0.23.0.
inplace : bool, default False
Whether or not to rename the categories inplace or return a copy of
this categorical with renamed categories.
Returns
-------
cat : Categorical or None
With ``inplace=False``, the new categorical is returned.
With ``inplace=True``, there is no return value.
Raises
------
ValueError
If new categories are list-like and do not have the same number of
items than the current categories or do not validate as categories
See Also
--------
reorder_categories : Reorder categories.
add_categories : Add new categories.
remove_categories : Remove the specified categories.
remove_unused_categories : Remove categories which are not used.
set_categories : Set the categories to the specified ones.
Examples
--------
>>> c = pd.Categorical(['a', 'a', 'b'])
>>> c.rename_categories([0, 1])
[0, 0, 1]
Categories (2, int64): [0, 1]
For dict-like ``new_categories``, extra keys are ignored and
categories not in the dictionary are passed through
>>> c.rename_categories({'a': 'A', 'c': 'C'})
[A, A, b]
Categories (2, object): [A, b]
You may also provide a callable to create the new categories
>>> c.rename_categories(lambda x: x.upper())
[A, A, B]
Categories (2, object): [A, B]
"""
inplace = validate_bool_kwarg(inplace, "inplace")
cat = self if inplace else self.copy()
if is_dict_like(new_categories):
cat.categories = [new_categories.get(item, item) for item in cat.categories]
elif callable(new_categories):
cat.categories = [new_categories(item) for item in cat.categories]
else:
cat.categories = new_categories
if not inplace:
return cat
def reorder_categories(self, new_categories, ordered=None, inplace=False):
"""
Reorder categories as specified in new_categories.
`new_categories` need to include all old categories and no new category
items.
Parameters
----------
new_categories : Index-like
The categories in new order.
ordered : bool, optional
Whether or not the categorical is treated as a ordered categorical.
If not given, do not change the ordered information.
inplace : bool, default False
Whether or not to reorder the categories inplace or return a copy of
this categorical with reordered categories.
Returns
-------
cat : Categorical with reordered categories or None if inplace.
Raises
------
ValueError
If the new categories do not contain all old category items or any
new ones
See Also
--------
rename_categories : Rename categories.
add_categories : Add new categories.
remove_categories : Remove the specified categories.
remove_unused_categories : Remove categories which are not used.
set_categories : Set the categories to the specified ones.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if set(self.dtype.categories) != set(new_categories):
raise ValueError(
"items in new_categories are not the same as in old categories"
)
return self.set_categories(new_categories, ordered=ordered, inplace=inplace)
def add_categories(self, new_categories, inplace=False):
"""
Add new categories.
`new_categories` will be included at the last/highest place in the
categories and will be unused directly after this call.
Parameters
----------
new_categories : category or list-like of category
The new categories to be included.
inplace : bool, default False
Whether or not to add the categories inplace or return a copy of
this categorical with added categories.
Returns
-------
cat : Categorical with new categories added or None if inplace.
Raises
------
ValueError
If the new categories include old categories or do not validate as
categories
See Also
--------
rename_categories : Rename categories.
reorder_categories : Reorder categories.
remove_categories : Remove the specified categories.
remove_unused_categories : Remove categories which are not used.
set_categories : Set the categories to the specified ones.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not is_list_like(new_categories):
new_categories = [new_categories]
already_included = set(new_categories) & set(self.dtype.categories)
if len(already_included) != 0:
raise ValueError(
f"new categories must not include old categories: {already_included}"
)
new_categories = list(self.dtype.categories) + list(new_categories)
new_dtype = CategoricalDtype(new_categories, self.ordered)
cat = self if inplace else self.copy()
cat._dtype = new_dtype
cat._codes = coerce_indexer_dtype(cat._codes, new_dtype.categories)
if not inplace:
return cat
def remove_categories(self, removals, inplace=False):
"""
Remove the specified categories.
`removals` must be included in the old categories. Values which were in
the removed categories will be set to NaN
Parameters
----------
removals : category or list of categories
The categories which should be removed.
inplace : bool, default False
Whether or not to remove the categories inplace or return a copy of
this categorical with removed categories.
Returns
-------
cat : Categorical with removed categories or None if inplace.
Raises
------
ValueError
If the removals are not contained in the categories
See Also
--------
rename_categories : Rename categories.
reorder_categories : Reorder categories.
add_categories : Add new categories.
remove_unused_categories : Remove categories which are not used.
set_categories : Set the categories to the specified ones.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not is_list_like(removals):
removals = [removals]
removal_set = set(removals)
not_included = removal_set - set(self.dtype.categories)
new_categories = [c for c in self.dtype.categories if c not in removal_set]
# GH 10156
if any(isna(removals)):
not_included = {x for x in not_included if notna(x)}
new_categories = [x for x in new_categories if notna(x)]
if len(not_included) != 0:
raise ValueError(f"removals must all be in old categories: {not_included}")
return self.set_categories(
new_categories, ordered=self.ordered, rename=False, inplace=inplace
)
def remove_unused_categories(self, inplace=False):
"""
Remove categories which are not used.
Parameters
----------
inplace : bool, default False
Whether or not to drop unused categories inplace or return a copy of
this categorical with unused categories dropped.
Returns
-------
cat : Categorical with unused categories dropped or None if inplace.
See Also
--------
rename_categories : Rename categories.
reorder_categories : Reorder categories.
add_categories : Add new categories.
remove_categories : Remove the specified categories.
set_categories : Set the categories to the specified ones.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
cat = self if inplace else self.copy()
idx, inv = np.unique(cat._codes, return_inverse=True)
if idx.size != 0 and idx[0] == -1: # na sentinel
idx, inv = idx[1:], inv - 1
new_categories = cat.dtype.categories.take(idx)
new_dtype = CategoricalDtype._from_fastpath(
new_categories, ordered=self.ordered
)
cat._dtype = new_dtype
cat._codes = coerce_indexer_dtype(inv, new_dtype.categories)
if not inplace:
return cat
def map(self, mapper):
"""
Map categories using input correspondence (dict, Series, or function).
Maps the categories to new categories. If the mapping correspondence is
one-to-one the result is a :class:`~pandas.Categorical` which has the
same order property as the original, otherwise a :class:`~pandas.Index`
is returned. NaN values are unaffected.
If a `dict` or :class:`~pandas.Series` is used any unmapped category is
mapped to `NaN`. Note that if this happens an :class:`~pandas.Index`
will be returned.
Parameters
----------
mapper : function, dict, or Series
Mapping correspondence.
Returns
-------
pandas.Categorical or pandas.Index
Mapped categorical.
See Also
--------
CategoricalIndex.map : Apply a mapping correspondence on a
:class:`~pandas.CategoricalIndex`.
Index.map : Apply a mapping correspondence on an
:class:`~pandas.Index`.
Series.map : Apply a mapping correspondence on a
:class:`~pandas.Series`.
Series.apply : Apply more complex functions on a
:class:`~pandas.Series`.
Examples
--------
>>> cat = pd.Categorical(['a', 'b', 'c'])
>>> cat
[a, b, c]
Categories (3, object): [a, b, c]
>>> cat.map(lambda x: x.upper())
[A, B, C]
Categories (3, object): [A, B, C]
>>> cat.map({'a': 'first', 'b': 'second', 'c': 'third'})
[first, second, third]
Categories (3, object): [first, second, third]
If the mapping is one-to-one the ordering of the categories is
preserved:
>>> cat = pd.Categorical(['a', 'b', 'c'], ordered=True)
>>> cat
[a, b, c]
Categories (3, object): [a < b < c]
>>> cat.map({'a': 3, 'b': 2, 'c': 1})
[3, 2, 1]
Categories (3, int64): [3 < 2 < 1]
If the mapping is not one-to-one an :class:`~pandas.Index` is returned:
>>> cat.map({'a': 'first', 'b': 'second', 'c': 'first'})
Index(['first', 'second', 'first'], dtype='object')
If a `dict` is used, all unmapped categories are mapped to `NaN` and
the result is an :class:`~pandas.Index`:
>>> cat.map({'a': 'first', 'b': 'second'})
Index(['first', 'second', nan], dtype='object')
"""
new_categories = self.categories.map(mapper)
try:
return self.from_codes(
self._codes.copy(), categories=new_categories, ordered=self.ordered
)
except ValueError:
# NA values are represented in self._codes with -1
# np.take causes NA values to take final element in new_categories
if np.any(self._codes == -1):
new_categories = new_categories.insert(len(new_categories), np.nan)
return np.take(new_categories, self._codes)
__eq__ = _cat_compare_op(operator.eq)
__ne__ = _cat_compare_op(operator.ne)
__lt__ = _cat_compare_op(operator.lt)
__gt__ = _cat_compare_op(operator.gt)
__le__ = _cat_compare_op(operator.le)
__ge__ = _cat_compare_op(operator.ge)
def shift(self, periods, fill_value=None):
"""
Shift Categorical by desired number of periods.
Parameters
----------
periods : int
Number of periods to move, can be positive or negative
fill_value : object, optional
The scalar value to use for newly introduced missing values.
.. versionadded:: 0.24.0
Returns
-------
shifted : Categorical
"""
# since categoricals always have ndim == 1, an axis parameter
# doesn't make any sense here.
codes = self.codes
if codes.ndim > 1:
raise NotImplementedError("Categorical with ndim > 1.")
fill_value = self._validate_fill_value(fill_value)
codes = shift(codes, periods, axis=0, fill_value=fill_value)
return self._constructor(codes, dtype=self.dtype, fastpath=True)
def _validate_fill_value(self, fill_value):
"""
Convert a user-facing fill_value to a representation to use with our
underlying ndarray, raising ValueError if this is not possible.
Parameters
----------
fill_value : object
Returns
-------
fill_value : int
Raises
------
ValueError
"""
if isna(fill_value):
fill_value = -1
elif fill_value in self.categories:
fill_value = self.categories.get_loc(fill_value)
else:
raise ValueError(
f"'fill_value={fill_value}' is not present "
"in this Categorical's categories"
)
return fill_value
def __array__(self, dtype=None) -> np.ndarray:
"""
The numpy array interface.
Returns
-------
numpy.array
A numpy array of either the specified dtype or,
if dtype==None (default), the same dtype as
categorical.categories.dtype.
"""
ret = take_1d(self.categories.values, self._codes)
if dtype and not is_dtype_equal(dtype, self.categories.dtype):
return np.asarray(ret, dtype)
if is_extension_array_dtype(ret):
# When we're a Categorical[ExtensionArray], like Interval,
# we need to ensure __array__ get's all the way to an
# ndarray.
ret = np.asarray(ret)
return ret
def __array_ufunc__(self, ufunc, method, *inputs, **kwargs):
# for binary ops, use our custom dunder methods
result = ops.maybe_dispatch_ufunc_to_dunder_op(
self, ufunc, method, *inputs, **kwargs
)
if result is not NotImplemented:
return result
# for all other cases, raise for now (similarly as what happens in
# Series.__array_prepare__)
raise TypeError(
f"Object with dtype {self.dtype} cannot perform "
f"the numpy op {ufunc.__name__}"
)
def __setstate__(self, state):
"""Necessary for making this object picklable"""
if not isinstance(state, dict):
raise Exception("invalid pickle state")
if "_dtype" not in state:
state["_dtype"] = CategoricalDtype(state["_categories"], state["_ordered"])
for k, v in state.items():
setattr(self, k, v)
@property
def nbytes(self):
return self._codes.nbytes + self.dtype.categories.values.nbytes
def memory_usage(self, deep=False):
"""
Memory usage of my values
Parameters
----------
deep : bool
Introspect the data deeply, interrogate
`object` dtypes for system-level memory consumption
Returns
-------
bytes used
Notes
-----
Memory usage does not include memory consumed by elements that
are not components of the array if deep=False
See Also
--------
numpy.ndarray.nbytes
"""
return self._codes.nbytes + self.dtype.categories.memory_usage(deep=deep)
@doc(_shared_docs["searchsorted"], klass="Categorical")
def searchsorted(self, value, side="left", sorter=None):
# searchsorted is very performance sensitive. By converting codes
# to same dtype as self.codes, we get much faster performance.
if is_scalar(value):
codes = self.categories.get_loc(value)
codes = self.codes.dtype.type(codes)
else:
locs = [self.categories.get_loc(x) for x in value]
codes = np.array(locs, dtype=self.codes.dtype)
return self.codes.searchsorted(codes, side=side, sorter=sorter)
def isna(self):
"""
Detect missing values
Missing values (-1 in .codes) are detected.
Returns
-------
a boolean array of whether my values are null
See Also
--------
isna : Top-level isna.
isnull : Alias of isna.
Categorical.notna : Boolean inverse of Categorical.isna.
"""
ret = self._codes == -1
return ret
isnull = isna
def notna(self):
"""
Inverse of isna
Both missing values (-1 in .codes) and NA as a category are detected as
null.
Returns
-------
a boolean array of whether my values are not null
See Also
--------
notna : Top-level notna.
notnull : Alias of notna.
Categorical.isna : Boolean inverse of Categorical.notna.
"""
return ~self.isna()
notnull = notna
def dropna(self):
"""
Return the Categorical without null values.
Missing values (-1 in .codes) are detected.
Returns
-------
valid : Categorical
"""
result = self[self.notna()]
return result
def value_counts(self, dropna=True):
"""
Return a Series containing counts of each category.
Every category will have an entry, even those with a count of 0.
Parameters
----------
dropna : bool, default True
Don't include counts of NaN.
Returns
-------
counts : Series
See Also
--------
Series.value_counts
"""
from pandas import Series, CategoricalIndex
code, cat = self._codes, self.categories
ncat, mask = len(cat), 0 <= code
ix, clean = np.arange(ncat), mask.all()
if dropna or clean:
obs = code if clean else code[mask]
count = np.bincount(obs, minlength=ncat or 0)
else:
count = np.bincount(np.where(mask, code, ncat))
ix = np.append(ix, -1)
ix = self._constructor(ix, dtype=self.dtype, fastpath=True)
return Series(count, index=CategoricalIndex(ix), dtype="int64")
def _internal_get_values(self):
"""
Return the values.
For internal compatibility with pandas formatting.
Returns
-------
np.ndarray or Index
A numpy array of the same dtype as categorical.categories.dtype or
Index if datetime / periods.
"""
# if we are a datetime and period index, return Index to keep metadata
if needs_i8_conversion(self.categories.dtype):
return self.categories.take(self._codes, fill_value=np.nan)
elif is_integer_dtype(self.categories) and -1 in self._codes:
return self.categories.astype("object").take(self._codes, fill_value=np.nan)
return np.array(self)
def check_for_ordered(self, op):
""" assert that we are ordered """
if not self.ordered:
raise TypeError(
f"Categorical is not ordered for operation {op}\n"
"you can use .as_ordered() to change the "
"Categorical to an ordered one\n"
)
def _values_for_argsort(self):
return self._codes
def argsort(self, ascending=True, kind="quicksort", **kwargs):
"""
Return the indices that would sort the Categorical.
.. versionchanged:: 0.25.0
Changed to sort missing values at the end.
Parameters
----------
ascending : bool, default True
Whether the indices should result in an ascending
or descending sort.
kind : {'quicksort', 'mergesort', 'heapsort'}, optional
Sorting algorithm.
**kwargs:
passed through to :func:`numpy.argsort`.
Returns
-------
numpy.array
See Also
--------
numpy.ndarray.argsort
Notes
-----
While an ordering is applied to the category values, arg-sorting
in this context refers more to organizing and grouping together
based on matching category values. Thus, this function can be
called on an unordered Categorical instance unlike the functions
'Categorical.min' and 'Categorical.max'.
Examples
--------
>>> pd.Categorical(['b', 'b', 'a', 'c']).argsort()
array([2, 0, 1, 3])
>>> cat = pd.Categorical(['b', 'b', 'a', 'c'],
... categories=['c', 'b', 'a'],
... ordered=True)
>>> cat.argsort()
array([3, 0, 1, 2])
Missing values are placed at the end
>>> cat = pd.Categorical([2, None, 1])
>>> cat.argsort()
array([2, 0, 1])
"""
return super().argsort(ascending=ascending, kind=kind, **kwargs)
def sort_values(
self, inplace: bool = False, ascending: bool = True, na_position: str = "last",
):
"""
Sort the Categorical by category value returning a new
Categorical by default.
While an ordering is applied to the category values, sorting in this
context refers more to organizing and grouping together based on
matching category values. Thus, this function can be called on an
unordered Categorical instance unlike the functions 'Categorical.min'
and 'Categorical.max'.
Parameters
----------
inplace : bool, default False
Do operation in place.
ascending : bool, default True
Order ascending. Passing False orders descending. The
ordering parameter provides the method by which the
category values are organized.
na_position : {'first', 'last'} (optional, default='last')
'first' puts NaNs at the beginning
'last' puts NaNs at the end
Returns
-------
Categorical or None
See Also
--------
Categorical.sort
Series.sort_values
Examples
--------
>>> c = pd.Categorical([1, 2, 2, 1, 5])
>>> c
[1, 2, 2, 1, 5]
Categories (3, int64): [1, 2, 5]
>>> c.sort_values()
[1, 1, 2, 2, 5]
Categories (3, int64): [1, 2, 5]
>>> c.sort_values(ascending=False)
[5, 2, 2, 1, 1]
Categories (3, int64): [1, 2, 5]
Inplace sorting can be done as well:
>>> c.sort_values(inplace=True)
>>> c
[1, 1, 2, 2, 5]
Categories (3, int64): [1, 2, 5]
>>>
>>> c = pd.Categorical([1, 2, 2, 1, 5])
'sort_values' behaviour with NaNs. Note that 'na_position'
is independent of the 'ascending' parameter:
>>> c = pd.Categorical([np.nan, 2, 2, np.nan, 5])
>>> c
[NaN, 2, 2, NaN, 5]
Categories (2, int64): [2, 5]
>>> c.sort_values()
[2, 2, 5, NaN, NaN]
Categories (2, int64): [2, 5]
>>> c.sort_values(ascending=False)
[5, 2, 2, NaN, NaN]
Categories (2, int64): [2, 5]
>>> c.sort_values(na_position='first')
[NaN, NaN, 2, 2, 5]
Categories (2, int64): [2, 5]
>>> c.sort_values(ascending=False, na_position='first')
[NaN, NaN, 5, 2, 2]
Categories (2, int64): [2, 5]
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if na_position not in ["last", "first"]:
raise ValueError(f"invalid na_position: {repr(na_position)}")
sorted_idx = nargsort(self, ascending=ascending, na_position=na_position)
if inplace:
self._codes = self._codes[sorted_idx]
else:
return self._constructor(
values=self._codes[sorted_idx], dtype=self.dtype, fastpath=True
)
def _values_for_rank(self):
"""
For correctly ranking ordered categorical data. See GH#15420
Ordered categorical data should be ranked on the basis of
codes with -1 translated to NaN.
Returns
-------
numpy.array
"""
from pandas import Series
if self.ordered:
values = self.codes
mask = values == -1
if mask.any():
values = values.astype("float64")
values[mask] = np.nan
elif self.categories.is_numeric():
values = np.array(self)
else:
# reorder the categories (so rank can use the float codes)
# instead of passing an object array to rank
values = np.array(
self.rename_categories(Series(self.categories).rank().values)
)
return values
def view(self, dtype=None):
if dtype is not None:
raise NotImplementedError(dtype)
return self._constructor(values=self._codes, dtype=self.dtype, fastpath=True)
def to_dense(self):
"""
Return my 'dense' representation
For internal compatibility with numpy arrays.
Returns
-------
dense : array
"""
warn(
"Categorical.to_dense is deprecated and will be removed in "
"a future version. Use np.asarray(cat) instead.",
FutureWarning,
stacklevel=2,
)
return np.asarray(self)
def fillna(self, value=None, method=None, limit=None):
"""
Fill NA/NaN values using the specified method.
Parameters
----------
value : scalar, dict, Series
If a scalar value is passed it is used to fill all missing values.
Alternatively, a Series or dict can be used to fill in different
values for each index. The value should not be a list. The
value(s) passed should either be in the categories or should be
NaN.
method : {'backfill', 'bfill', 'pad', 'ffill', None}, default None
Method to use for filling holes in reindexed Series
pad / ffill: propagate last valid observation forward to next valid
backfill / bfill: use NEXT valid observation to fill gap
limit : int, default None
(Not implemented yet for Categorical!)
If method is specified, this is the maximum number of consecutive
NaN values to forward/backward fill. In other words, if there is
a gap with more than this number of consecutive NaNs, it will only
be partially filled. If method is not specified, this is the
maximum number of entries along the entire axis where NaNs will be
filled.
Returns
-------
filled : Categorical with NA/NaN filled
"""
value, method = validate_fillna_kwargs(
value, method, validate_scalar_dict_value=False
)
if value is None:
value = np.nan
if limit is not None:
raise NotImplementedError(
"specifying a limit for fillna has not been implemented yet"
)
codes = self._codes
# pad / bfill
if method is not None:
# TODO: dispatch when self.categories is EA-dtype
values = np.asarray(self).reshape(-1, len(self))
values = interpolate_2d(values, method, 0, None, value).astype(
self.categories.dtype
)[0]
codes = _get_codes_for_values(values, self.categories)
else:
# If value is a dict or a Series (a dict value has already
# been converted to a Series)
if isinstance(value, (np.ndarray, Categorical, ABCSeries)):
# We get ndarray or Categorical if called via Series.fillna,
# where it will unwrap another aligned Series before getting here
mask = ~algorithms.isin(value, self.categories)
if not isna(value[mask]).all():
raise ValueError("fill value must be in categories")
values_codes = _get_codes_for_values(value, self.categories)
indexer = np.where(codes == -1)
codes = codes.copy()
codes[indexer] = values_codes[indexer]
# If value is not a dict or Series it should be a scalar
elif is_hashable(value):
if not isna(value) and value not in self.categories:
raise ValueError("fill value must be in categories")
mask = codes == -1
if mask.any():
codes = codes.copy()
if isna(value):
codes[mask] = -1
else:
codes[mask] = self.categories.get_loc(value)
else:
raise TypeError(
f"'value' parameter must be a scalar, dict "
f"or Series, but you passed a {type(value).__name__}"
)
return self._constructor(codes, dtype=self.dtype, fastpath=True)
def take(self: _T, indexer, allow_fill: bool = False, fill_value=None) -> _T:
"""
Take elements from the Categorical.
Parameters
----------
indexer : sequence of int
The indices in `self` to take. The meaning of negative values in
`indexer` depends on the value of `allow_fill`.
allow_fill : bool, default False
How to handle negative values in `indexer`.
* False: negative values in `indices` indicate positional indices
from the right. This is similar to
:func:`numpy.take`.
* True: negative values in `indices` indicate missing values
(the default). These values are set to `fill_value`. Any other
other negative values raise a ``ValueError``.
.. versionchanged:: 1.0.0
Default value changed from ``True`` to ``False``.
fill_value : object
The value to use for `indices` that are missing (-1), when
``allow_fill=True``. This should be the category, i.e. a value
in ``self.categories``, not a code.
Returns
-------
Categorical
This Categorical will have the same categories and ordered as
`self`.
See Also
--------
Series.take : Similar method for Series.
numpy.ndarray.take : Similar method for NumPy arrays.
Examples
--------
>>> cat = pd.Categorical(['a', 'a', 'b'])
>>> cat
[a, a, b]
Categories (2, object): [a, b]
Specify ``allow_fill==False`` to have negative indices mean indexing
from the right.
>>> cat.take([0, -1, -2], allow_fill=False)
[a, b, a]
Categories (2, object): [a, b]
With ``allow_fill=True``, indices equal to ``-1`` mean "missing"
values that should be filled with the `fill_value`, which is
``np.nan`` by default.
>>> cat.take([0, -1, -1], allow_fill=True)
[a, NaN, NaN]
Categories (2, object): [a, b]
The fill value can be specified.
>>> cat.take([0, -1, -1], allow_fill=True, fill_value='a')
[a, a, a]
Categories (2, object): [a, b]
Specifying a fill value that's not in ``self.categories``
will raise a ``ValueError``.
"""
return NDArrayBackedExtensionArray.take(
self, indexer, allow_fill=allow_fill, fill_value=fill_value
)
# ------------------------------------------------------------------
# NDArrayBackedExtensionArray compat
@property
def _ndarray(self) -> np.ndarray:
return self._codes
def _from_backing_data(self, arr: np.ndarray) -> "Categorical":
return self._constructor(arr, dtype=self.dtype, fastpath=True)
# ------------------------------------------------------------------
def take_nd(self, indexer, allow_fill: bool = False, fill_value=None):
# GH#27745 deprecate alias that other EAs dont have
warn(
"Categorical.take_nd is deprecated, use Categorical.take instead",
FutureWarning,
stacklevel=2,
)
return self.take(indexer, allow_fill=allow_fill, fill_value=fill_value)
def __iter__(self):
"""
Returns an Iterator over the values of this Categorical.
"""
return iter(self._internal_get_values().tolist())
def __contains__(self, key) -> bool:
"""
Returns True if `key` is in this Categorical.
"""
# if key is a NaN, check if any NaN is in self.
if is_scalar(key) and isna(key):
return self.isna().any()
return contains(self, key, container=self._codes)
def _tidy_repr(self, max_vals=10, footer=True) -> str:
"""
a short repr displaying only max_vals and an optional (but default
footer)
"""
num = max_vals // 2
head = self[:num]._get_repr(length=False, footer=False)
tail = self[-(max_vals - num) :]._get_repr(length=False, footer=False)
result = f"{head[:-1]}, ..., {tail[1:]}"
if footer:
result = f"{result}\n{self._repr_footer()}"
return str(result)
def _repr_categories(self):
"""
return the base repr for the categories
"""
max_categories = (
10
if get_option("display.max_categories") == 0
else get_option("display.max_categories")
)
from pandas.io.formats import format as fmt
if len(self.categories) > max_categories:
num = max_categories // 2
head = fmt.format_array(self.categories[:num], None)
tail = fmt.format_array(self.categories[-num:], None)
category_strs = head + ["..."] + tail
else:
category_strs = fmt.format_array(self.categories, None)
# Strip all leading spaces, which format_array adds for columns...
category_strs = [x.strip() for x in category_strs]
return category_strs
def _repr_categories_info(self) -> str:
"""
Returns a string representation of the footer.
"""
category_strs = self._repr_categories()
dtype = str(self.categories.dtype)
levheader = f"Categories ({len(self.categories)}, {dtype}): "
width, height = get_terminal_size()
max_width = get_option("display.width") or width
if console.in_ipython_frontend():
# 0 = no breaks
max_width = 0
levstring = ""
start = True
cur_col_len = len(levheader) # header
sep_len, sep = (3, " < ") if self.ordered else (2, ", ")
linesep = sep.rstrip() + "\n" # remove whitespace
for val in category_strs:
if max_width != 0 and cur_col_len + sep_len + len(val) > max_width:
levstring += linesep + (" " * (len(levheader) + 1))
cur_col_len = len(levheader) + 1 # header + a whitespace
elif not start:
levstring += sep
cur_col_len += len(val)
levstring += val
start = False
# replace to simple save space by
return levheader + "[" + levstring.replace(" < ... < ", " ... ") + "]"
def _repr_footer(self) -> str:
info = self._repr_categories_info()
return f"Length: {len(self)}\n{info}"
def _get_repr(self, length=True, na_rep="NaN", footer=True) -> str:
from pandas.io.formats import format as fmt
formatter = fmt.CategoricalFormatter(
self, length=length, na_rep=na_rep, footer=footer
)
result = formatter.to_string()
return str(result)
def __repr__(self) -> str:
"""
String representation.
"""
_maxlen = 10
if len(self._codes) > _maxlen:
result = self._tidy_repr(_maxlen)
elif len(self._codes) > 0:
result = self._get_repr(length=len(self) > _maxlen)
else:
msg = self._get_repr(length=False, footer=True).replace("\n", ", ")
result = f"[], {msg}"
return result
def _maybe_coerce_indexer(self, indexer):
"""
return an indexer coerced to the codes dtype
"""
if isinstance(indexer, np.ndarray) and indexer.dtype.kind == "i":
indexer = indexer.astype(self._codes.dtype)
return indexer
def __getitem__(self, key):
"""
Return an item.
"""
if isinstance(key, (int, np.integer)):
i = self._codes[key]
if i == -1:
return np.nan
else:
return self.categories[i]
key = check_array_indexer(self, key)
result = self._codes[key]
if result.ndim > 1:
deprecate_ndim_indexing(result)
return result
return self._constructor(result, dtype=self.dtype, fastpath=True)
def __setitem__(self, key, value):
"""
Item assignment.
Raises
------
ValueError
If (one or more) Value is not in categories or if a assigned
`Categorical` does not have the same categories
"""
value = extract_array(value, extract_numpy=True)
# require identical categories set
if isinstance(value, Categorical):
if not is_dtype_equal(self, value):
raise ValueError(
"Cannot set a Categorical with another, "
"without identical categories"
)
if not self.categories.equals(value.categories):
new_codes = recode_for_categories(
value.codes, value.categories, self.categories
)
value = Categorical.from_codes(new_codes, dtype=self.dtype)
rvalue = value if is_list_like(value) else [value]
from pandas import Index
to_add = Index(rvalue).difference(self.categories)
# no assignments of values not in categories, but it's always ok to set
# something to np.nan
if len(to_add) and not isna(to_add).all():
raise ValueError(
"Cannot setitem on a Categorical with a new "
"category, set the categories first"
)
# set by position
if isinstance(key, (int, np.integer)):
pass
# tuple of indexers (dataframe)
elif isinstance(key, tuple):
# only allow 1 dimensional slicing, but can
# in a 2-d case be passd (slice(None),....)
if len(key) == 2:
if not com.is_null_slice(key[0]):
raise AssertionError("invalid slicing for a 1-ndim categorical")
key = key[1]
elif len(key) == 1:
key = key[0]
else:
raise AssertionError("invalid slicing for a 1-ndim categorical")
# slicing in Series or Categorical
elif isinstance(key, slice):
pass
# else: array of True/False in Series or Categorical
lindexer = self.categories.get_indexer(rvalue)
lindexer = self._maybe_coerce_indexer(lindexer)
key = check_array_indexer(self, key)
self._codes[key] = lindexer
def _reverse_indexer(self) -> Dict[Hashable, np.ndarray]:
"""
Compute the inverse of a categorical, returning
a dict of categories -> indexers.
*This is an internal function*
Returns
-------
dict of categories -> indexers
Examples
--------
>>> c = pd.Categorical(list('aabca'))
>>> c
[a, a, b, c, a]
Categories (3, object): [a, b, c]
>>> c.categories
Index(['a', 'b', 'c'], dtype='object')
>>> c.codes
array([0, 0, 1, 2, 0], dtype=int8)
>>> c._reverse_indexer()
{'a': array([0, 1, 4]), 'b': array([2]), 'c': array([3])}
"""
categories = self.categories
r, counts = libalgos.groupsort_indexer(
self.codes.astype("int64"), categories.size
)
counts = counts.cumsum()
_result = (r[start:end] for start, end in zip(counts, counts[1:]))
result = dict(zip(categories, _result))
return result
# reduction ops #
def _reduce(self, name, axis=0, **kwargs):
func = getattr(self, name, None)
if func is None:
raise TypeError(f"Categorical cannot perform the operation {name}")
return func(**kwargs)
@deprecate_kwarg(old_arg_name="numeric_only", new_arg_name="skipna")
def min(self, skipna=True):
"""
The minimum value of the object.
Only ordered `Categoricals` have a minimum!
.. versionchanged:: 1.0.0
Returns an NA value on empty arrays
Raises
------
TypeError
If the `Categorical` is not `ordered`.
Returns
-------
min : the minimum of this `Categorical`
"""
self.check_for_ordered("min")
if not len(self._codes):
return self.dtype.na_value
good = self._codes != -1
if not good.all():
if skipna and good.any():
pointer = self._codes[good].min()
else:
return np.nan
else:
pointer = self._codes.min()
return self.categories[pointer]
@deprecate_kwarg(old_arg_name="numeric_only", new_arg_name="skipna")
def max(self, skipna=True):
"""
The maximum value of the object.
Only ordered `Categoricals` have a maximum!
.. versionchanged:: 1.0.0
Returns an NA value on empty arrays
Raises
------
TypeError
If the `Categorical` is not `ordered`.
Returns
-------
max : the maximum of this `Categorical`
"""
self.check_for_ordered("max")
if not len(self._codes):
return self.dtype.na_value
good = self._codes != -1
if not good.all():
if skipna and good.any():
pointer = self._codes[good].max()
else:
return np.nan
else:
pointer = self._codes.max()
return self.categories[pointer]
def mode(self, dropna=True):
"""
Returns the mode(s) of the Categorical.
Always returns `Categorical` even if only one value.
Parameters
----------
dropna : bool, default True
Don't consider counts of NaN/NaT.
.. versionadded:: 0.24.0
Returns
-------
modes : `Categorical` (sorted)
"""
codes = self._codes
if dropna:
good = self._codes != -1
codes = self._codes[good]
codes = sorted(htable.mode_int64(ensure_int64(codes), dropna))
return self._constructor(values=codes, dtype=self.dtype, fastpath=True)
def unique(self):
"""
Return the ``Categorical`` which ``categories`` and ``codes`` are
unique. Unused categories are NOT returned.
- unordered category: values and categories are sorted by appearance
order.
- ordered category: values are sorted by appearance order, categories
keeps existing order.
Returns
-------
unique values : ``Categorical``
See Also
--------
pandas.unique
CategoricalIndex.unique
Series.unique
Examples
--------
An unordered Categorical will return categories in the
order of appearance.
>>> pd.Categorical(list("baabc")).unique()
[b, a, c]
Categories (3, object): [b, a, c]
>>> pd.Categorical(list("baabc"), categories=list("abc")).unique()
[b, a, c]
Categories (3, object): [b, a, c]
An ordered Categorical preserves the category ordering.
>>> pd.Categorical(
... list("baabc"), categories=list("abc"), ordered=True
... ).unique()
[b, a, c]
Categories (3, object): [a < b < c]
"""
# unlike np.unique, unique1d does not sort
unique_codes = unique1d(self.codes)
cat = self.copy()
# keep nan in codes
cat._codes = unique_codes
# exclude nan from indexer for categories
take_codes = unique_codes[unique_codes != -1]
if self.ordered:
take_codes = np.sort(take_codes)
return cat.set_categories(cat.categories.take(take_codes))
def _values_for_factorize(self):
codes = self.codes.astype("int64")
return codes, -1
@classmethod
def _from_factorized(cls, uniques, original):
return original._constructor(
original.categories.take(uniques), dtype=original.dtype
)
def equals(self, other):
"""
Returns True if categorical arrays are equal.
Parameters
----------
other : `Categorical`
Returns
-------
bool
"""
if self.is_dtype_equal(other):
if self.categories.equals(other.categories):
# fastpath to avoid re-coding
other_codes = other._codes
else:
other_codes = recode_for_categories(
other.codes, other.categories, self.categories
)
return np.array_equal(self._codes, other_codes)
return False
def is_dtype_equal(self, other):
"""
Returns True if categoricals are the same dtype
same categories, and same ordered
Parameters
----------
other : Categorical
Returns
-------
bool
"""
try:
return hash(self.dtype) == hash(other.dtype)
except (AttributeError, TypeError):
return False
def describe(self):
"""
Describes this Categorical
Returns
-------
description: `DataFrame`
A dataframe with frequency and counts by category.
"""
counts = self.value_counts(dropna=False)
freqs = counts / float(counts.sum())
from pandas.core.reshape.concat import concat
result = concat([counts, freqs], axis=1)
result.columns = ["counts", "freqs"]
result.index.name = "categories"
return result
# Implement the ExtensionArray interface
@property
def _can_hold_na(self):
return True
@classmethod
def _concat_same_type(self, to_concat):
from pandas.core.dtypes.concat import union_categoricals
return union_categoricals(to_concat)
def isin(self, values):
"""
Check whether `values` are contained in Categorical.
Return a boolean NumPy Array showing whether each element in
the Categorical matches an element in the passed sequence of
`values` exactly.
Parameters
----------
values : set or list-like
The sequence of values to test. Passing in a single string will
raise a ``TypeError``. Instead, turn a single string into a
list of one element.
Returns
-------
isin : numpy.ndarray (bool dtype)
Raises
------
TypeError
* If `values` is not a set or list-like
See Also
--------
pandas.Series.isin : Equivalent method on Series.
Examples
--------
>>> s = pd.Categorical(['lama', 'cow', 'lama', 'beetle', 'lama',
... 'hippo'])
>>> s.isin(['cow', 'lama'])
array([ True, True, True, False, True, False])
Passing a single string as ``s.isin('lama')`` will raise an error. Use
a list of one element instead:
>>> s.isin(['lama'])
array([ True, False, True, False, True, False])
"""
if not is_list_like(values):
values_type = type(values).__name__
raise TypeError(
"only list-like objects are allowed to be passed "
f"to isin(), you passed a [{values_type}]"
)
values = sanitize_array(values, None, None)
null_mask = np.asarray(isna(values))
code_values = self.categories.get_indexer(values)
code_values = code_values[null_mask | (code_values >= 0)]
return algorithms.isin(self.codes, code_values)
def replace(self, to_replace, value, inplace: bool = False):
"""
Replaces all instances of one value with another
Parameters
----------
to_replace: object
The value to be replaced
value: object
The value to replace it with
inplace: bool
Whether the operation is done in-place
Returns
-------
None if inplace is True, otherwise the new Categorical after replacement
Examples
--------
>>> s = pd.Categorical([1, 2, 1, 3])
>>> s.replace(1, 3)
[3, 2, 3, 3]
Categories (2, int64): [2, 3]
"""
inplace = validate_bool_kwarg(inplace, "inplace")
cat = self if inplace else self.copy()
# build a dict of (to replace -> value) pairs
if is_list_like(to_replace):
# if to_replace is list-like and value is scalar
replace_dict = {replace_value: value for replace_value in to_replace}
else:
# if both to_replace and value are scalar
replace_dict = {to_replace: value}
# other cases, like if both to_replace and value are list-like or if
# to_replace is a dict, are handled separately in NDFrame
for replace_value, new_value in replace_dict.items():
if new_value == replace_value:
continue
if replace_value in cat.categories:
if isna(new_value):
cat.remove_categories(replace_value, inplace=True)
continue
categories = cat.categories.tolist()
index = categories.index(replace_value)
if new_value in cat.categories:
value_index = categories.index(new_value)
cat._codes[cat._codes == index] = value_index
cat.remove_categories(replace_value, inplace=True)
else:
categories[index] = new_value
cat.rename_categories(categories, inplace=True)
if not inplace:
return cat
# The Series.cat accessor
@delegate_names(
delegate=Categorical, accessors=["categories", "ordered"], typ="property"
)
@delegate_names(
delegate=Categorical,
accessors=[
"rename_categories",
"reorder_categories",
"add_categories",
"remove_categories",
"remove_unused_categories",
"set_categories",
"as_ordered",
"as_unordered",
],
typ="method",
)
class CategoricalAccessor(PandasDelegate, PandasObject, NoNewAttributesMixin):
"""
Accessor object for categorical properties of the Series values.
Be aware that assigning to `categories` is a inplace operation, while all
methods return new categorical data per default (but can be called with
`inplace=True`).
Parameters
----------
data : Series or CategoricalIndex
Examples
--------
>>> s = pd.Series(list("abbccc")).astype("category")
>>> s
0 a
1 b
2 b
3 c
4 c
5 c
dtype: category
Categories (3, object): [a, b, c]
>>> s.cat.categories
Index(['a', 'b', 'c'], dtype='object')
>>> s.cat.rename_categories(list("cba"))
0 c
1 b
2 b
3 a
4 a
5 a
dtype: category
Categories (3, object): [c, b, a]
>>> s.cat.reorder_categories(list("cba"))
0 a
1 b
2 b
3 c
4 c
5 c
dtype: category
Categories (3, object): [c, b, a]
>>> s.cat.add_categories(["d", "e"])
0 a
1 b
2 b
3 c
4 c
5 c
dtype: category
Categories (5, object): [a, b, c, d, e]
>>> s.cat.remove_categories(["a", "c"])
0 NaN
1 b
2 b
3 NaN
4 NaN
5 NaN
dtype: category
Categories (1, object): [b]
>>> s1 = s.cat.add_categories(["d", "e"])
>>> s1.cat.remove_unused_categories()
0 a
1 b
2 b
3 c
4 c
5 c
dtype: category
Categories (3, object): [a, b, c]
>>> s.cat.set_categories(list("abcde"))
0 a
1 b
2 b
3 c
4 c
5 c
dtype: category
Categories (5, object): [a, b, c, d, e]
>>> s.cat.as_ordered()
0 a
1 b
2 b
3 c
4 c
5 c
dtype: category
Categories (3, object): [a < b < c]
>>> s.cat.as_unordered()
0 a
1 b
2 b
3 c
4 c
5 c
dtype: category
Categories (3, object): [a, b, c]
"""
def __init__(self, data):
self._validate(data)
self._parent = data.values
self._index = data.index
self._name = data.name
self._freeze()
@staticmethod
def _validate(data):
if not is_categorical_dtype(data.dtype):
raise AttributeError("Can only use .cat accessor with a 'category' dtype")
def _delegate_property_get(self, name):
return getattr(self._parent, name)
def _delegate_property_set(self, name, new_values):
return setattr(self._parent, name, new_values)
@property
def codes(self):
"""
Return Series of codes as well as the index.
"""
from pandas import Series
return Series(self._parent.codes, index=self._index)
def _delegate_method(self, name, *args, **kwargs):
from pandas import Series
method = getattr(self._parent, name)
res = method(*args, **kwargs)
if res is not None:
return Series(res, index=self._index, name=self._name)
# utility routines
def _get_codes_for_values(values, categories):
"""
utility routine to turn values into codes given the specified categories
"""
dtype_equal = is_dtype_equal(values.dtype, categories.dtype)
if is_extension_array_dtype(categories.dtype) and is_object_dtype(values):
# Support inferring the correct extension dtype from an array of
# scalar objects. e.g.
# Categorical(array[Period, Period], categories=PeriodIndex(...))
cls = categories.dtype.construct_array_type()
values = maybe_cast_to_extension_array(cls, values)
if not isinstance(values, cls):
# exception raised in _from_sequence
values = ensure_object(values)
categories = ensure_object(categories)
elif not dtype_equal:
values = ensure_object(values)
categories = ensure_object(categories)
hash_klass, vals = _get_data_algo(values)
_, cats = _get_data_algo(categories)
t = hash_klass(len(cats))
t.map_locations(cats)
return coerce_indexer_dtype(t.lookup(vals), cats)
def recode_for_categories(codes: np.ndarray, old_categories, new_categories):
"""
Convert a set of codes for to a new set of categories
Parameters
----------
codes : np.ndarray
old_categories, new_categories : Index
Returns
-------
new_codes : np.ndarray[np.int64]
Examples
--------
>>> old_cat = pd.Index(['b', 'a', 'c'])
>>> new_cat = pd.Index(['a', 'b'])
>>> codes = np.array([0, 1, 1, 2])
>>> recode_for_categories(codes, old_cat, new_cat)
array([ 1, 0, 0, -1], dtype=int8)
"""
if len(old_categories) == 0:
# All null anyway, so just retain the nulls
return codes.copy()
elif new_categories.equals(old_categories):
# Same categories, so no need to actually recode
return codes.copy()
indexer = coerce_indexer_dtype(
new_categories.get_indexer(old_categories), new_categories
)
new_codes = take_1d(indexer, codes.copy(), fill_value=-1)
return new_codes
def _convert_to_list_like(list_like):
if hasattr(list_like, "dtype"):
return list_like
if isinstance(list_like, list):
return list_like
if is_sequence(list_like) or isinstance(list_like, tuple) or is_iterator(list_like):
return list(list_like)
elif is_scalar(list_like):
return [list_like]
else:
# TODO: is this reached?
return [list_like]
def factorize_from_iterable(values):
"""
Factorize an input `values` into `categories` and `codes`. Preserves
categorical dtype in `categories`.
*This is an internal function*
Parameters
----------
values : list-like
Returns
-------
codes : ndarray
categories : Index
If `values` has a categorical dtype, then `categories` is
a CategoricalIndex keeping the categories and order of `values`.
"""
if not is_list_like(values):
raise TypeError("Input must be list-like")
if is_categorical_dtype(values):
values = extract_array(values)
# The Categorical we want to build has the same categories
# as values but its codes are by def [0, ..., len(n_categories) - 1]
cat_codes = np.arange(len(values.categories), dtype=values.codes.dtype)
categories = Categorical.from_codes(cat_codes, dtype=values.dtype)
codes = values.codes
else:
# The value of ordered is irrelevant since we don't use cat as such,
# but only the resulting categories, the order of which is independent
# from ordered. Set ordered to False as default. See GH #15457
cat = Categorical(values, ordered=False)
categories = cat.categories
codes = cat.codes
return codes, categories
def factorize_from_iterables(iterables):
"""
A higher-level wrapper over `factorize_from_iterable`.
*This is an internal function*
Parameters
----------
iterables : list-like of list-likes
Returns
-------
codes_list : list of ndarrays
categories_list : list of Indexes
Notes
-----
See `factorize_from_iterable` for more info.
"""
if len(iterables) == 0:
# For consistency, it should return a list of 2 lists.
return [[], []]
return map(list, zip(*(factorize_from_iterable(it) for it in iterables)))
import operator
from shutil import get_terminal_size
from typing import Dict, Hashable, List, Type, Union, cast
from warnings import warn
import numpy as np
from pandas._config import get_option
from pandas._libs import algos as libalgos, hashtable as htable
from pandas._typing import ArrayLike, Dtype, Ordered, Scalar
from pandas.util._decorators import cache_readonly, deprecate_kwarg, doc
from pandas.util._validators import validate_bool_kwarg, validate_fillna_kwargs
from pandas.core.dtypes.cast import (
coerce_indexer_dtype,
maybe_cast_to_extension_array,
maybe_infer_to_datetimelike,
)
from pandas.core.dtypes.common import (
ensure_int64,
ensure_object,
is_categorical_dtype,
is_datetime64_dtype,
is_dict_like,
is_dtype_equal,
is_extension_array_dtype,
is_integer_dtype,
is_iterator,
is_list_like,
is_object_dtype,
is_scalar,
is_sequence,
is_timedelta64_dtype,
needs_i8_conversion,
)
from pandas.core.dtypes.dtypes import CategoricalDtype
from pandas.core.dtypes.generic import ABCIndexClass, ABCSeries
from pandas.core.dtypes.inference import is_hashable
from pandas.core.dtypes.missing import is_valid_nat_for_dtype, isna, notna
from pandas.core import ops
from pandas.core.accessor import PandasDelegate, delegate_names
import pandas.core.algorithms as algorithms
from pandas.core.algorithms import _get_data_algo, factorize, take_1d, unique1d
from pandas.core.array_algos.transforms import shift
from pandas.core.arrays._mixins import _T, NDArrayBackedExtensionArray
from pandas.core.base import NoNewAttributesMixin, PandasObject, _shared_docs
import pandas.core.common as com
from pandas.core.construction import array, extract_array, sanitize_array
from pandas.core.indexers import check_array_indexer, deprecate_ndim_indexing
from pandas.core.missing import interpolate_2d
from pandas.core.ops.common import unpack_zerodim_and_defer
from pandas.core.sorting import nargsort
from pandas.io.formats import console
def _cat_compare_op(op):
opname = f"__{op.__name__}__"
@unpack_zerodim_and_defer(opname)
def func(self, other):
if is_list_like(other) and len(other) != len(self):
# TODO: Could this fail if the categories are listlike objects?
raise ValueError("Lengths must match.")
if not self.ordered:
if opname in ["__lt__", "__gt__", "__le__", "__ge__"]:
raise TypeError(
"Unordered Categoricals can only compare equality or not"
)
if isinstance(other, Categorical):
# Two Categoricals can only be be compared if the categories are
# the same (maybe up to ordering, depending on ordered)
msg = "Categoricals can only be compared if 'categories' are the same."
if len(self.categories) != len(other.categories):
raise TypeError(msg + " Categories are different lengths")
elif self.ordered and not (self.categories == other.categories).all():
raise TypeError(msg)
elif not set(self.categories) == set(other.categories):
raise TypeError(msg)
if not (self.ordered == other.ordered):
raise TypeError(
"Categoricals can only be compared if 'ordered' is the same"
)
if not self.ordered and not self.categories.equals(other.categories):
# both unordered and different order
other_codes = _get_codes_for_values(other, self.categories)
else:
other_codes = other._codes
f = getattr(self._codes, opname)
ret = f(other_codes)
mask = (self._codes == -1) | (other_codes == -1)
if mask.any():
# In other series, the leads to False, so do that here too
if opname == "__ne__":
ret[(self._codes == -1) & (other_codes == -1)] = True
else:
ret[mask] = False
return ret
if is_scalar(other):
if other in self.categories:
i = self.categories.get_loc(other)
ret = getattr(self._codes, opname)(i)
if opname not in {"__eq__", "__ge__", "__gt__"}:
# check for NaN needed if we are not equal or larger
mask = self._codes == -1
ret[mask] = False
return ret
else:
if opname == "__eq__":
return np.zeros(len(self), dtype=bool)
elif opname == "__ne__":
return np.ones(len(self), dtype=bool)
else:
raise TypeError(
f"Cannot compare a Categorical for op {opname} with a "
"scalar, which is not a category."
)
else:
# allow categorical vs object dtype array comparisons for equality
# these are only positional comparisons
if opname in ["__eq__", "__ne__"]:
return getattr(np.array(self), opname)(np.array(other))
raise TypeError(
f"Cannot compare a Categorical for op {opname} with "
f"type {type(other)}.\nIf you want to compare values, "
"use 'np.asarray(cat) <op> other'."
)
func.__name__ = opname
return func
def contains(cat, key, container):
"""
Helper for membership check for ``key`` in ``cat``.
This is a helper method for :method:`__contains__`
and :class:`CategoricalIndex.__contains__`.
Returns True if ``key`` is in ``cat.categories`` and the
location of ``key`` in ``categories`` is in ``container``.
Parameters
----------
cat : :class:`Categorical`or :class:`categoricalIndex`
key : a hashable object
The key to check membership for.
container : Container (e.g. list-like or mapping)
The container to check for membership in.
Returns
-------
is_in : bool
True if ``key`` is in ``self.categories`` and location of
``key`` in ``categories`` is in ``container``, else False.
Notes
-----
This method does not check for NaN values. Do that separately
before calling this method.
"""
hash(key)
# get location of key in categories.
# If a KeyError, the key isn't in categories, so logically
# can't be in container either.
try:
loc = cat.categories.get_loc(key)
except (KeyError, TypeError):
return False
# loc is the location of key in categories, but also the *value*
# for key in container. So, `key` may be in categories,
# but still not in `container`. Example ('b' in categories,
# but not in values):
# 'b' in Categorical(['a'], categories=['a', 'b']) # False
if is_scalar(loc):
return loc in container
else:
# if categories is an IntervalIndex, loc is an array.
return any(loc_ in container for loc_ in loc)
class Categorical(NDArrayBackedExtensionArray, PandasObject):
"""
Represent a categorical variable in classic R / S-plus fashion.
`Categoricals` can only take on only a limited, and usually fixed, number
of possible values (`categories`). In contrast to statistical categorical
variables, a `Categorical` might have an order, but numerical operations
(additions, divisions, ...) are not possible.
All values of the `Categorical` are either in `categories` or `np.nan`.
Assigning values outside of `categories` will raise a `ValueError`. Order
is defined by the order of the `categories`, not lexical order of the
values.
Parameters
----------
values : list-like
The values of the categorical. If categories are given, values not in
categories will be replaced with NaN.
categories : Index-like (unique), optional
The unique categories for this categorical. If not given, the
categories are assumed to be the unique values of `values` (sorted, if
possible, otherwise in the order in which they appear).
ordered : bool, default False
Whether or not this categorical is treated as a ordered categorical.
If True, the resulting categorical will be ordered.
An ordered categorical respects, when sorted, the order of its
`categories` attribute (which in turn is the `categories` argument, if
provided).
dtype : CategoricalDtype
An instance of ``CategoricalDtype`` to use for this categorical.
Attributes
----------
categories : Index
The categories of this categorical
codes : ndarray
The codes (integer positions, which point to the categories) of this
categorical, read only.
ordered : bool
Whether or not this Categorical is ordered.
dtype : CategoricalDtype
The instance of ``CategoricalDtype`` storing the ``categories``
and ``ordered``.
Methods
-------
from_codes
__array__
Raises
------
ValueError
If the categories do not validate.
TypeError
If an explicit ``ordered=True`` is given but no `categories` and the
`values` are not sortable.
See Also
--------
CategoricalDtype : Type for categorical data.
CategoricalIndex : An Index with an underlying ``Categorical``.
Notes
-----
See the `user guide
<https://pandas.pydata.org/pandas-docs/stable/user_guide/categorical.html>`_
for more.
Examples
--------
>>> pd.Categorical([1, 2, 3, 1, 2, 3])
[1, 2, 3, 1, 2, 3]
Categories (3, int64): [1, 2, 3]
>>> pd.Categorical(['a', 'b', 'c', 'a', 'b', 'c'])
[a, b, c, a, b, c]
Categories (3, object): [a, b, c]
Ordered `Categoricals` can be sorted according to the custom order
of the categories and can have a min and max value.
>>> c = pd.Categorical(['a', 'b', 'c', 'a', 'b', 'c'], ordered=True,
... categories=['c', 'b', 'a'])
>>> c
[a, b, c, a, b, c]
Categories (3, object): [c < b < a]
>>> c.min()
'c'
"""
# For comparisons, so that numpy uses our implementation if the compare
# ops, which raise
__array_priority__ = 1000
_dtype = CategoricalDtype(ordered=False)
# tolist is not actually deprecated, just suppressed in the __dir__
_deprecations = PandasObject._deprecations | frozenset(["tolist"])
_typ = "categorical"
def __init__(
self, values, categories=None, ordered=None, dtype=None, fastpath=False
):
dtype = CategoricalDtype._from_values_or_dtype(
values, categories, ordered, dtype
)
# At this point, dtype is always a CategoricalDtype, but
# we may have dtype.categories be None, and we need to
# infer categories in a factorization step further below
if fastpath:
self._codes = coerce_indexer_dtype(values, dtype.categories)
self._dtype = self._dtype.update_dtype(dtype)
return
# null_mask indicates missing values we want to exclude from inference.
# This means: only missing values in list-likes (not arrays/ndframes).
null_mask = np.array(False)
# sanitize input
if is_categorical_dtype(values):
if dtype.categories is None:
dtype = CategoricalDtype(values.categories, dtype.ordered)
elif not isinstance(values, (ABCIndexClass, ABCSeries)):
# sanitize_array coerces np.nan to a string under certain versions
# of numpy
values = maybe_infer_to_datetimelike(values, convert_dates=True)
if not isinstance(values, np.ndarray):
values = _convert_to_list_like(values)
# By convention, empty lists result in object dtype:
sanitize_dtype = np.dtype("O") if len(values) == 0 else None
null_mask = isna(values)
if null_mask.any():
values = [values[idx] for idx in np.where(~null_mask)[0]]
values = sanitize_array(values, None, dtype=sanitize_dtype)
if dtype.categories is None:
try:
codes, categories = factorize(values, sort=True)
except TypeError as err:
codes, categories = factorize(values, sort=False)
if dtype.ordered:
# raise, as we don't have a sortable data structure and so
# the user should give us one by specifying categories
raise TypeError(
"'values' is not ordered, please "
"explicitly specify the categories order "
"by passing in a categories argument."
) from err
except ValueError as err:
# FIXME
raise NotImplementedError(
"> 1 ndim Categorical are not supported at this time"
) from err
# we're inferring from values
dtype = CategoricalDtype(categories, dtype.ordered)
elif is_categorical_dtype(values.dtype):
old_codes = (
values._values.codes if isinstance(values, ABCSeries) else values.codes
)
codes = recode_for_categories(
old_codes, values.dtype.categories, dtype.categories
)
else:
codes = _get_codes_for_values(values, dtype.categories)
if null_mask.any():
# Reinsert -1 placeholders for previously removed missing values
full_codes = -np.ones(null_mask.shape, dtype=codes.dtype)
full_codes[~null_mask] = codes
codes = full_codes
self._dtype = self._dtype.update_dtype(dtype)
self._codes = coerce_indexer_dtype(codes, dtype.categories)
@property
def categories(self):
"""
The categories of this categorical.
Setting assigns new values to each category (effectively a rename of
each individual category).
The assigned value has to be a list-like object. All items must be
unique and the number of items in the new categories must be the same
as the number of items in the old categories.
Assigning to `categories` is a inplace operation!
Raises
------
ValueError
If the new categories do not validate as categories or if the
number of new categories is unequal the number of old categories
See Also
--------
rename_categories : Rename categories.
reorder_categories : Reorder categories.
add_categories : Add new categories.
remove_categories : Remove the specified categories.
remove_unused_categories : Remove categories which are not used.
set_categories : Set the categories to the specified ones.
"""
return self.dtype.categories
@categories.setter
def categories(self, categories):
new_dtype = CategoricalDtype(categories, ordered=self.ordered)
if self.dtype.categories is not None and len(self.dtype.categories) != len(
new_dtype.categories
):
raise ValueError(
"new categories need to have the same number of "
"items as the old categories!"
)
self._dtype = new_dtype
@property
def ordered(self) -> Ordered:
"""
Whether the categories have an ordered relationship.
"""
return self.dtype.ordered
@property
def dtype(self) -> CategoricalDtype:
"""
The :class:`~pandas.api.types.CategoricalDtype` for this instance.
"""
return self._dtype
@property
def _constructor(self) -> Type["Categorical"]:
return Categorical
@classmethod
def _from_sequence(cls, scalars, dtype=None, copy=False):
return Categorical(scalars, dtype=dtype)
def _formatter(self, boxed=False):
# Defer to CategoricalFormatter's formatter.
return None
def astype(self, dtype: Dtype, copy: bool = True) -> ArrayLike:
"""
Coerce this type to another dtype
Parameters
----------
dtype : numpy dtype or pandas type
copy : bool, default True
By default, astype always returns a newly allocated object.
If copy is set to False and dtype is categorical, the original
object is returned.
"""
if is_categorical_dtype(dtype):
dtype = cast(Union[str, CategoricalDtype], dtype)
# GH 10696/18593
dtype = self.dtype.update_dtype(dtype)
self = self.copy() if copy else self
if dtype == self.dtype:
return self
return self._set_dtype(dtype)
if is_extension_array_dtype(dtype):
return array(self, dtype=dtype, copy=copy)
if is_integer_dtype(dtype) and self.isna().any():
raise ValueError("Cannot convert float NaN to integer")
return np.array(self, dtype=dtype, copy=copy)
@cache_readonly
def itemsize(self) -> int:
"""
return the size of a single category
"""
return self.categories.itemsize
def tolist(self) -> List[Scalar]:
"""
Return a list of the values.
These are each a scalar type, which is a Python scalar
(for str, int, float) or a pandas scalar
(for Timestamp/Timedelta/Interval/Period)
"""
return list(self)
to_list = tolist
@classmethod
def _from_inferred_categories(
cls, inferred_categories, inferred_codes, dtype, true_values=None
):
"""
Construct a Categorical from inferred values.
For inferred categories (`dtype` is None) the categories are sorted.
For explicit `dtype`, the `inferred_categories` are cast to the
appropriate type.
Parameters
----------
inferred_categories : Index
inferred_codes : Index
dtype : CategoricalDtype or 'category'
true_values : list, optional
If none are provided, the default ones are
"True", "TRUE", and "true."
Returns
-------
Categorical
"""
from pandas import Index, to_numeric, to_datetime, to_timedelta
cats = Index(inferred_categories)
known_categories = (
isinstance(dtype, CategoricalDtype) and dtype.categories is not None
)
if known_categories:
# Convert to a specialized type with `dtype` if specified.
if dtype.categories.is_numeric():
cats = to_numeric(inferred_categories, errors="coerce")
elif is_datetime64_dtype(dtype.categories):
cats = to_datetime(inferred_categories, errors="coerce")
elif is_timedelta64_dtype(dtype.categories):
cats = to_timedelta(inferred_categories, errors="coerce")
elif dtype.categories.is_boolean():
if true_values is None:
true_values = ["True", "TRUE", "true"]
cats = cats.isin(true_values)
if known_categories:
# Recode from observation order to dtype.categories order.
categories = dtype.categories
codes = recode_for_categories(inferred_codes, cats, categories)
elif not cats.is_monotonic_increasing:
# Sort categories and recode for unknown categories.
unsorted = cats.copy()
categories = cats.sort_values()
codes = recode_for_categories(inferred_codes, unsorted, categories)
dtype = CategoricalDtype(categories, ordered=False)
else:
dtype = CategoricalDtype(cats, ordered=False)
codes = inferred_codes
return cls(codes, dtype=dtype, fastpath=True)
@classmethod
def from_codes(cls, codes, categories=None, ordered=None, dtype=None):
"""
Make a Categorical type from codes and categories or dtype.
This constructor is useful if you already have codes and
categories/dtype and so do not need the (computation intensive)
factorization step, which is usually done on the constructor.
If your data does not follow this convention, please use the normal
constructor.
Parameters
----------
codes : array-like of int
An integer array, where each integer points to a category in
categories or dtype.categories, or else is -1 for NaN.
categories : index-like, optional
The categories for the categorical. Items need to be unique.
If the categories are not given here, then they must be provided
in `dtype`.
ordered : bool, optional
Whether or not this categorical is treated as an ordered
categorical. If not given here or in `dtype`, the resulting
categorical will be unordered.
dtype : CategoricalDtype or "category", optional
If :class:`CategoricalDtype`, cannot be used together with
`categories` or `ordered`.
.. versionadded:: 0.24.0
When `dtype` is provided, neither `categories` nor `ordered`
should be provided.
Returns
-------
Categorical
Examples
--------
>>> dtype = pd.CategoricalDtype(['a', 'b'], ordered=True)
>>> pd.Categorical.from_codes(codes=[0, 1, 0, 1], dtype=dtype)
[a, b, a, b]
Categories (2, object): [a < b]
"""
dtype = CategoricalDtype._from_values_or_dtype(
categories=categories, ordered=ordered, dtype=dtype
)
if dtype.categories is None:
msg = (
"The categories must be provided in 'categories' or "
"'dtype'. Both were None."
)
raise ValueError(msg)
if is_extension_array_dtype(codes) and is_integer_dtype(codes):
# Avoid the implicit conversion of Int to object
if isna(codes).any():
raise ValueError("codes cannot contain NA values")
codes = codes.to_numpy(dtype=np.int64)
else:
codes = np.asarray(codes)
if len(codes) and not is_integer_dtype(codes):
raise ValueError("codes need to be array-like integers")
if len(codes) and (codes.max() >= len(dtype.categories) or codes.min() < -1):
raise ValueError("codes need to be between -1 and len(categories)-1")
return cls(codes, dtype=dtype, fastpath=True)
@property
def codes(self) -> np.ndarray:
"""
The category codes of this categorical.
Codes are an array of integers which are the positions of the actual
values in the categories array.
There is no setter, use the other categorical methods and the normal item
setter to change values in the categorical.
Returns
-------
ndarray[int]
A non-writable view of the `codes` array.
"""
v = self._codes.view()
v.flags.writeable = False
return v
def _set_categories(self, categories, fastpath=False):
"""
Sets new categories inplace
Parameters
----------
fastpath : bool, default False
Don't perform validation of the categories for uniqueness or nulls
Examples
--------
>>> c = pd.Categorical(['a', 'b'])
>>> c
[a, b]
Categories (2, object): [a, b]
>>> c._set_categories(pd.Index(['a', 'c']))
>>> c
[a, c]
Categories (2, object): [a, c]
"""
if fastpath:
new_dtype = CategoricalDtype._from_fastpath(categories, self.ordered)
else:
new_dtype = CategoricalDtype(categories, ordered=self.ordered)
if (
not fastpath
and self.dtype.categories is not None
and len(new_dtype.categories) != len(self.dtype.categories)
):
raise ValueError(
"new categories need to have the same number of "
"items than the old categories!"
)
self._dtype = new_dtype
def _set_dtype(self, dtype: CategoricalDtype) -> "Categorical":
"""
Internal method for directly updating the CategoricalDtype
Parameters
----------
dtype : CategoricalDtype
Notes
-----
We don't do any validation here. It's assumed that the dtype is
a (valid) instance of `CategoricalDtype`.
"""
codes = recode_for_categories(self.codes, self.categories, dtype.categories)
return type(self)(codes, dtype=dtype, fastpath=True)
def set_ordered(self, value, inplace=False):
"""
Set the ordered attribute to the boolean value.
Parameters
----------
value : bool
Set whether this categorical is ordered (True) or not (False).
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to the value.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
new_dtype = CategoricalDtype(self.categories, ordered=value)
cat = self if inplace else self.copy()
cat._dtype = new_dtype
if not inplace:
return cat
def as_ordered(self, inplace=False):
"""
Set the Categorical to be ordered.
Parameters
----------
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to True.
Returns
-------
Categorical
Ordered Categorical.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
return self.set_ordered(True, inplace=inplace)
def as_unordered(self, inplace=False):
"""
Set the Categorical to be unordered.
Parameters
----------
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to False.
Returns
-------
Categorical
Unordered Categorical.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
return self.set_ordered(False, inplace=inplace)
def set_categories(self, new_categories, ordered=None, rename=False, inplace=False):
"""
Set the categories to the specified new_categories.
`new_categories` can include new categories (which will result in
unused categories) or remove old categories (which results in values
set to NaN). If `rename==True`, the categories will simple be renamed
(less or more items than in old categories will result in values set to
NaN or in unused categories respectively).
This method can be used to perform more than one action of adding,
removing, and reordering simultaneously and is therefore faster than
performing the individual steps via the more specialised methods.
On the other hand this methods does not do checks (e.g., whether the
old categories are included in the new categories on a reorder), which
can result in surprising changes, for example when using special string
dtypes, which does not considers a S1 string equal to a single char
python string.
Parameters
----------
new_categories : Index-like
The categories in new order.
ordered : bool, default False
Whether or not the categorical is treated as a ordered categorical.
If not given, do not change the ordered information.
rename : bool, default False
Whether or not the new_categories should be considered as a rename
of the old categories or as reordered categories.
inplace : bool, default False
Whether or not to reorder the categories in-place or return a copy
of this categorical with reordered categories.
Returns
-------
Categorical with reordered categories or None if inplace.
Raises
------
ValueError
If new_categories does not validate as categories
See Also
--------
rename_categories : Rename categories.
reorder_categories : Reorder categories.
add_categories : Add new categories.
remove_categories : Remove the specified categories.
remove_unused_categories : Remove categories which are not used.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if ordered is None:
ordered = self.dtype.ordered
new_dtype = CategoricalDtype(new_categories, ordered=ordered)
cat = self if inplace else self.copy()
if rename:
if cat.dtype.categories is not None and len(new_dtype.categories) < len(
cat.dtype.categories
):
# remove all _codes which are larger and set to -1/NaN
cat._codes[cat._codes >= len(new_dtype.categories)] = -1
else:
codes = recode_for_categories(
cat.codes, cat.categories, new_dtype.categories
)
cat._codes = codes
cat._dtype = new_dtype
if not inplace:
return cat
def rename_categories(self, new_categories, inplace=False):
"""
Rename categories.
Parameters
----------
new_categories : list-like, dict-like or callable
New categories which will replace old categories.
* list-like: all items must be unique and the number of items in
the new categories must match the existing number of categories.
* dict-like: specifies a mapping from
old categories to new. Categories not contained in the mapping
are passed through and extra categories in the mapping are
ignored.
* callable : a callable that is called on all items in the old
categories and whose return values comprise the new categories.
.. versionadded:: 0.23.0.
inplace : bool, default False
Whether or not to rename the categories inplace or return a copy of
this categorical with renamed categories.
Returns
-------
cat : Categorical or None
With ``inplace=False``, the new categorical is returned.
With ``inplace=True``, there is no return value.
Raises
------
ValueError
If new categories are list-like and do not have the same number of
items than the current categories or do not validate as categories
See Also
--------
reorder_categories : Reorder categories.
add_categories : Add new categories.
remove_categories : Remove the specified categories.
remove_unused_categories : Remove categories which are not used.
set_categories : Set the categories to the specified ones.
Examples
--------
>>> c = pd.Categorical(['a', 'a', 'b'])
>>> c.rename_categories([0, 1])
[0, 0, 1]
Categories (2, int64): [0, 1]
For dict-like ``new_categories``, extra keys are ignored and
categories not in the dictionary are passed through
>>> c.rename_categories({'a': 'A', 'c': 'C'})
[A, A, b]
Categories (2, object): [A, b]
You may also provide a callable to create the new categories
>>> c.rename_categories(lambda x: x.upper())
[A, A, B]
Categories (2, object): [A, B]
"""
inplace = validate_bool_kwarg(inplace, "inplace")
cat = self if inplace else self.copy()
if is_dict_like(new_categories):
cat.categories = [new_categories.get(item, item) for item in cat.categories]
elif callable(new_categories):
cat.categories = [new_categories(item) for item in cat.categories]
else:
cat.categories = new_categories
if not inplace:
return cat
def reorder_categories(self, new_categories, ordered=None, inplace=False):
"""
Reorder categories as specified in new_categories.
`new_categories` need to include all old categories and no new category
items.
Parameters
----------
new_categories : Index-like
The categories in new order.
ordered : bool, optional
Whether or not the categorical is treated as a ordered categorical.
If not given, do not change the ordered information.
inplace : bool, default False
Whether or not to reorder the categories inplace or return a copy of
this categorical with reordered categories.
Returns
-------
cat : Categorical with reordered categories or None if inplace.
Raises
------
ValueError
If the new categories do not contain all old category items or any
new ones
See Also
--------
rename_categories : Rename categories.
add_categories : Add new categories.
remove_categories : Remove the specified categories.
remove_unused_categories : Remove categories which are not used.
set_categories : Set the categories to the specified ones.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if set(self.dtype.categories) != set(new_categories):
raise ValueError(
"items in new_categories are not the same as in old categories"
)
return self.set_categories(new_categories, ordered=ordered, inplace=inplace)
def add_categories(self, new_categories, inplace=False):
"""
Add new categories.
`new_categories` will be included at the last/highest place in the
categories and will be unused directly after this call.
Parameters
----------
new_categories : category or list-like of category
The new categories to be included.
inplace : bool, default False
Whether or not to add the categories inplace or return a copy of
this categorical with added categories.
Returns
-------
cat : Categorical with new categories added or None if inplace.
Raises
------
ValueError
If the new categories include old categories or do not validate as
categories
See Also
--------
rename_categories : Rename categories.
reorder_categories : Reorder categories.
remove_categories : Remove the specified categories.
remove_unused_categories : Remove categories which are not used.
set_categories : Set the categories to the specified ones.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not is_list_like(new_categories):
new_categories = [new_categories]
already_included = set(new_categories) & set(self.dtype.categories)
if len(already_included) != 0:
raise ValueError(
f"new categories must not include old categories: {already_included}"
)
new_categories = list(self.dtype.categories) + list(new_categories)
new_dtype = CategoricalDtype(new_categories, self.ordered)
cat = self if inplace else self.copy()
cat._dtype = new_dtype
cat._codes = coerce_indexer_dtype(cat._codes, new_dtype.categories)
if not inplace:
return cat
def remove_categories(self, removals, inplace=False):
"""
Remove the specified categories.
`removals` must be included in the old categories. Values which were in
the removed categories will be set to NaN
Parameters
----------
removals : category or list of categories
The categories which should be removed.
inplace : bool, default False
Whether or not to remove the categories inplace or return a copy of
this categorical with removed categories.
Returns
-------
cat : Categorical with removed categories or None if inplace.
Raises
------
ValueError
If the removals are not contained in the categories
See Also
--------
rename_categories : Rename categories.
reorder_categories : Reorder categories.
add_categories : Add new categories.
remove_unused_categories : Remove categories which are not used.
set_categories : Set the categories to the specified ones.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not is_list_like(removals):
removals = [removals]
removal_set = set(removals)
not_included = removal_set - set(self.dtype.categories)
new_categories = [c for c in self.dtype.categories if c not in removal_set]
# GH 10156
if any(isna(removals)):
not_included = {x for x in not_included if notna(x)}
new_categories = [x for x in new_categories if notna(x)]
if len(not_included) != 0:
raise ValueError(f"removals must all be in old categories: {not_included}")
return self.set_categories(
new_categories, ordered=self.ordered, rename=False, inplace=inplace
)
def remove_unused_categories(self, inplace=False):
"""
Remove categories which are not used.
Parameters
----------
inplace : bool, default False
Whether or not to drop unused categories inplace or return a copy of
this categorical with unused categories dropped.
Returns
-------
cat : Categorical with unused categories dropped or None if inplace.
See Also
--------
rename_categories : Rename categories.
reorder_categories : Reorder categories.
add_categories : Add new categories.
remove_categories : Remove the specified categories.
set_categories : Set the categories to the specified ones.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
cat = self if inplace else self.copy()
idx, inv = np.unique(cat._codes, return_inverse=True)
if idx.size != 0 and idx[0] == -1: # na sentinel
idx, inv = idx[1:], inv - 1
new_categories = cat.dtype.categories.take(idx)
new_dtype = CategoricalDtype._from_fastpath(
new_categories, ordered=self.ordered
)
cat._dtype = new_dtype
cat._codes = coerce_indexer_dtype(inv, new_dtype.categories)
if not inplace:
return cat
def map(self, mapper):
"""
Map categories using input correspondence (dict, Series, or function).
Maps the categories to new categories. If the mapping correspondence is
one-to-one the result is a :class:`~pandas.Categorical` which has the
same order property as the original, otherwise a :class:`~pandas.Index`
is returned. NaN values are unaffected.
If a `dict` or :class:`~pandas.Series` is used any unmapped category is
mapped to `NaN`. Note that if this happens an :class:`~pandas.Index`
will be returned.
Parameters
----------
mapper : function, dict, or Series
Mapping correspondence.
Returns
-------
pandas.Categorical or pandas.Index
Mapped categorical.
See Also
--------
CategoricalIndex.map : Apply a mapping correspondence on a
:class:`~pandas.CategoricalIndex`.
Index.map : Apply a mapping correspondence on an
:class:`~pandas.Index`.
Series.map : Apply a mapping correspondence on a
:class:`~pandas.Series`.
Series.apply : Apply more complex functions on a
:class:`~pandas.Series`.
Examples
--------
>>> cat = pd.Categorical(['a', 'b', 'c'])
>>> cat
[a, b, c]
Categories (3, object): [a, b, c]
>>> cat.map(lambda x: x.upper())
[A, B, C]
Categories (3, object): [A, B, C]
>>> cat.map({'a': 'first', 'b': 'second', 'c': 'third'})
[first, second, third]
Categories (3, object): [first, second, third]
If the mapping is one-to-one the ordering of the categories is
preserved:
>>> cat = pd.Categorical(['a', 'b', 'c'], ordered=True)
>>> cat
[a, b, c]
Categories (3, object): [a < b < c]
>>> cat.map({'a': 3, 'b': 2, 'c': 1})
[3, 2, 1]
Categories (3, int64): [3 < 2 < 1]
If the mapping is not one-to-one an :class:`~pandas.Index` is returned:
>>> cat.map({'a': 'first', 'b': 'second', 'c': 'first'})
Index(['first', 'second', 'first'], dtype='object')
If a `dict` is used, all unmapped categories are mapped to `NaN` and
the result is an :class:`~pandas.Index`:
>>> cat.map({'a': 'first', 'b': 'second'})
Index(['first', 'second', nan], dtype='object')
"""
new_categories = self.categories.map(mapper)
try:
return self.from_codes(
self._codes.copy(), categories=new_categories, ordered=self.ordered
)
except ValueError:
# NA values are represented in self._codes with -1
# np.take causes NA values to take final element in new_categories
if np.any(self._codes == -1):
new_categories = new_categories.insert(len(new_categories), np.nan)
return np.take(new_categories, self._codes)
__eq__ = _cat_compare_op(operator.eq)
__ne__ = _cat_compare_op(operator.ne)
__lt__ = _cat_compare_op(operator.lt)
__gt__ = _cat_compare_op(operator.gt)
__le__ = _cat_compare_op(operator.le)
__ge__ = _cat_compare_op(operator.ge)
def shift(self, periods, fill_value=None):
"""
Shift Categorical by desired number of periods.
Parameters
----------
periods : int
Number of periods to move, can be positive or negative
fill_value : object, optional
The scalar value to use for newly introduced missing values.
.. versionadded:: 0.24.0
Returns
-------
shifted : Categorical
"""
# since categoricals always have ndim == 1, an axis parameter
# doesn't make any sense here.
codes = self.codes
if codes.ndim > 1:
raise NotImplementedError("Categorical with ndim > 1.")
fill_value = self._validate_fill_value(fill_value)
codes = shift(codes, periods, axis=0, fill_value=fill_value)
return self._constructor(codes, dtype=self.dtype, fastpath=True)
def _validate_fill_value(self, fill_value):
"""
Convert a user-facing fill_value to a representation to use with our
underlying ndarray, raising ValueError if this is not possible.
Parameters
----------
fill_value : object
Returns
-------
fill_value : int
Raises
------
ValueError
"""
if isna(fill_value):
fill_value = -1
elif fill_value in self.categories:
fill_value = self.categories.get_loc(fill_value)
else:
raise ValueError(
f"'fill_value={fill_value}' is not present "
"in this Categorical's categories"
)
return fill_value
def __array__(self, dtype=None) -> np.ndarray:
"""
The numpy array interface.
Returns
-------
numpy.array
A numpy array of either the specified dtype or,
if dtype==None (default), the same dtype as
categorical.categories.dtype.
"""
ret = take_1d(self.categories.values, self._codes)
if dtype and not is_dtype_equal(dtype, self.categories.dtype):
return np.asarray(ret, dtype)
if is_extension_array_dtype(ret):
# When we're a Categorical[ExtensionArray], like Interval,
# we need to ensure __array__ get's all the way to an
# ndarray.
ret = np.asarray(ret)
return ret
def __array_ufunc__(self, ufunc, method, *inputs, **kwargs):
# for binary ops, use our custom dunder methods
result = ops.maybe_dispatch_ufunc_to_dunder_op(
self, ufunc, method, *inputs, **kwargs
)
if result is not NotImplemented:
return result
# for all other cases, raise for now (similarly as what happens in
# Series.__array_prepare__)
raise TypeError(
f"Object with dtype {self.dtype} cannot perform "
f"the numpy op {ufunc.__name__}"
)
def __setstate__(self, state):
"""Necessary for making this object picklable"""
if not isinstance(state, dict):
raise Exception("invalid pickle state")
if "_dtype" not in state:
state["_dtype"] = CategoricalDtype(state["_categories"], state["_ordered"])
for k, v in state.items():
setattr(self, k, v)
@property
def nbytes(self):
return self._codes.nbytes + self.dtype.categories.values.nbytes
def memory_usage(self, deep=False):
"""
Memory usage of my values
Parameters
----------
deep : bool
Introspect the data deeply, interrogate
`object` dtypes for system-level memory consumption
Returns
-------
bytes used
Notes
-----
Memory usage does not include memory consumed by elements that
are not components of the array if deep=False
See Also
--------
numpy.ndarray.nbytes
"""
return self._codes.nbytes + self.dtype.categories.memory_usage(deep=deep)
@doc(_shared_docs["searchsorted"], klass="Categorical")
def searchsorted(self, value, side="left", sorter=None):
# searchsorted is very performance sensitive. By converting codes
# to same dtype as self.codes, we get much faster performance.
if is_scalar(value):
codes = self.categories.get_loc(value)
codes = self.codes.dtype.type(codes)
else:
locs = [self.categories.get_loc(x) for x in value]
codes = np.array(locs, dtype=self.codes.dtype)
return self.codes.searchsorted(codes, side=side, sorter=sorter)
def isna(self):
"""
Detect missing values
Missing values (-1 in .codes) are detected.
Returns
-------
a boolean array of whether my values are null
See Also
--------
isna : Top-level isna.
isnull : Alias of isna.
Categorical.notna : Boolean inverse of Categorical.isna.
"""
ret = self._codes == -1
return ret
isnull = isna
def notna(self):
"""
Inverse of isna
Both missing values (-1 in .codes) and NA as a category are detected as
null.
Returns
-------
a boolean array of whether my values are not null
See Also
--------
notna : Top-level notna.
notnull : Alias of notna.
Categorical.isna : Boolean inverse of Categorical.notna.
"""
return ~self.isna()
notnull = notna
def dropna(self):
"""
Return the Categorical without null values.
Missing values (-1 in .codes) are detected.
Returns
-------
valid : Categorical
"""
result = self[self.notna()]
return result
def value_counts(self, dropna=True):
"""
Return a Series containing counts of each category.
Every category will have an entry, even those with a count of 0.
Parameters
----------
dropna : bool, default True
Don't include counts of NaN.
Returns
-------
counts : Series
See Also
--------
Series.value_counts
"""
from pandas import Series, CategoricalIndex
code, cat = self._codes, self.categories
ncat, mask = len(cat), 0 <= code
ix, clean = np.arange(ncat), mask.all()
if dropna or clean:
obs = code if clean else code[mask]
count = np.bincount(obs, minlength=ncat or 0)
else:
count = np.bincount(np.where(mask, code, ncat))
ix = np.append(ix, -1)
ix = self._constructor(ix, dtype=self.dtype, fastpath=True)
return Series(count, index=CategoricalIndex(ix), dtype="int64")
def _internal_get_values(self):
"""
Return the values.
For internal compatibility with pandas formatting.
Returns
-------
np.ndarray or Index
A numpy array of the same dtype as categorical.categories.dtype or
Index if datetime / periods.
"""
# if we are a datetime and period index, return Index to keep metadata
if needs_i8_conversion(self.categories.dtype):
return self.categories.take(self._codes, fill_value=np.nan)
elif is_integer_dtype(self.categories) and -1 in self._codes:
return self.categories.astype("object").take(self._codes, fill_value=np.nan)
return np.array(self)
def check_for_ordered(self, op):
""" assert that we are ordered """
if not self.ordered:
raise TypeError(
f"Categorical is not ordered for operation {op}\n"
"you can use .as_ordered() to change the "
"Categorical to an ordered one\n"
)
def _values_for_argsort(self):
return self._codes
def argsort(self, ascending=True, kind="quicksort", **kwargs):
"""
Return the indices that would sort the Categorical.
.. versionchanged:: 0.25.0
Changed to sort missing values at the end.
Parameters
----------
ascending : bool, default True
Whether the indices should result in an ascending
or descending sort.
kind : {'quicksort', 'mergesort', 'heapsort'}, optional
Sorting algorithm.
**kwargs:
passed through to :func:`numpy.argsort`.
Returns
-------
numpy.array
See Also
--------
numpy.ndarray.argsort
Notes
-----
While an ordering is applied to the category values, arg-sorting
in this context refers more to organizing and grouping together
based on matching category values. Thus, this function can be
called on an unordered Categorical instance unlike the functions
'Categorical.min' and 'Categorical.max'.
Examples
--------
>>> pd.Categorical(['b', 'b', 'a', 'c']).argsort()
array([2, 0, 1, 3])
>>> cat = pd.Categorical(['b', 'b', 'a', 'c'],
... categories=['c', 'b', 'a'],
... ordered=True)
>>> cat.argsort()
array([3, 0, 1, 2])
Missing values are placed at the end
>>> cat = pd.Categorical([2, None, 1])
>>> cat.argsort()
array([2, 0, 1])
"""
return super().argsort(ascending=ascending, kind=kind, **kwargs)
def sort_values(
self, inplace: bool = False, ascending: bool = True, na_position: str = "last",
):
"""
Sort the Categorical by category value returning a new
Categorical by default.
While an ordering is applied to the category values, sorting in this
context refers more to organizing and grouping together based on
matching category values. Thus, this function can be called on an
unordered Categorical instance unlike the functions 'Categorical.min'
and 'Categorical.max'.
Parameters
----------
inplace : bool, default False
Do operation in place.
ascending : bool, default True
Order ascending. Passing False orders descending. The
ordering parameter provides the method by which the
category values are organized.
na_position : {'first', 'last'} (optional, default='last')
'first' puts NaNs at the beginning
'last' puts NaNs at the end
Returns
-------
Categorical or None
See Also
--------
Categorical.sort
Series.sort_values
Examples
--------
>>> c = pd.Categorical([1, 2, 2, 1, 5])
>>> c
[1, 2, 2, 1, 5]
Categories (3, int64): [1, 2, 5]
>>> c.sort_values()
[1, 1, 2, 2, 5]
Categories (3, int64): [1, 2, 5]
>>> c.sort_values(ascending=False)
[5, 2, 2, 1, 1]
Categories (3, int64): [1, 2, 5]
Inplace sorting can be done as well:
>>> c.sort_values(inplace=True)
>>> c
[1, 1, 2, 2, 5]
Categories (3, int64): [1, 2, 5]
>>>
>>> c = pd.Categorical([1, 2, 2, 1, 5])
'sort_values' behaviour with NaNs. Note that 'na_position'
is independent of the 'ascending' parameter:
>>> c = pd.Categorical([np.nan, 2, 2, np.nan, 5])
>>> c
[NaN, 2, 2, NaN, 5]
Categories (2, int64): [2, 5]
>>> c.sort_values()
[2, 2, 5, NaN, NaN]
Categories (2, int64): [2, 5]
>>> c.sort_values(ascending=False)
[5, 2, 2, NaN, NaN]
Categories (2, int64): [2, 5]
>>> c.sort_values(na_position='first')
[NaN, NaN, 2, 2, 5]
Categories (2, int64): [2, 5]
>>> c.sort_values(ascending=False, na_position='first')
[NaN, NaN, 5, 2, 2]
Categories (2, int64): [2, 5]
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if na_position not in ["last", "first"]:
raise ValueError(f"invalid na_position: {repr(na_position)}")
sorted_idx = nargsort(self, ascending=ascending, na_position=na_position)
if inplace:
self._codes = self._codes[sorted_idx]
else:
return self._constructor(
values=self._codes[sorted_idx], dtype=self.dtype, fastpath=True
)
def _values_for_rank(self):
"""
For correctly ranking ordered categorical data. See GH#15420
Ordered categorical data should be ranked on the basis of
codes with -1 translated to NaN.
Returns
-------
numpy.array
"""
from pandas import Series
if self.ordered:
values = self.codes
mask = values == -1
if mask.any():
values = values.astype("float64")
values[mask] = np.nan
elif self.categories.is_numeric():
values = np.array(self)
else:
# reorder the categories (so rank can use the float codes)
# instead of passing an object array to rank
values = np.array(
self.rename_categories(Series(self.categories).rank().values)
)
return values
def view(self, dtype=None):
if dtype is not None:
raise NotImplementedError(dtype)
return self._constructor(values=self._codes, dtype=self.dtype, fastpath=True)
def to_dense(self):
"""
Return my 'dense' representation
For internal compatibility with numpy arrays.
Returns
-------
dense : array
"""
warn(
"Categorical.to_dense is deprecated and will be removed in "
"a future version. Use np.asarray(cat) instead.",
FutureWarning,
stacklevel=2,
)
return np.asarray(self)
def fillna(self, value=None, method=None, limit=None):
"""
Fill NA/NaN values using the specified method.
Parameters
----------
value : scalar, dict, Series
If a scalar value is passed it is used to fill all missing values.
Alternatively, a Series or dict can be used to fill in different
values for each index. The value should not be a list. The
value(s) passed should either be in the categories or should be
NaN.
method : {'backfill', 'bfill', 'pad', 'ffill', None}, default None
Method to use for filling holes in reindexed Series
pad / ffill: propagate last valid observation forward to next valid
backfill / bfill: use NEXT valid observation to fill gap
limit : int, default None
(Not implemented yet for Categorical!)
If method is specified, this is the maximum number of consecutive
NaN values to forward/backward fill. In other words, if there is
a gap with more than this number of consecutive NaNs, it will only
be partially filled. If method is not specified, this is the
maximum number of entries along the entire axis where NaNs will be
filled.
Returns
-------
filled : Categorical with NA/NaN filled
"""
value, method = validate_fillna_kwargs(
value, method, validate_scalar_dict_value=False
)
if value is None:
value = np.nan
if limit is not None:
raise NotImplementedError(
"specifying a limit for fillna has not been implemented yet"
)
codes = self._codes
# pad / bfill
if method is not None:
# TODO: dispatch when self.categories is EA-dtype
values = np.asarray(self).reshape(-1, len(self))
values = interpolate_2d(values, method, 0, None, value).astype(
self.categories.dtype
)[0]
codes = _get_codes_for_values(values, self.categories)
else:
# If value is a dict or a Series (a dict value has already
# been converted to a Series)
if isinstance(value, (np.ndarray, Categorical, ABCSeries)):
# We get ndarray or Categorical if called via Series.fillna,
# where it will unwrap another aligned Series before getting here
mask = ~algorithms.isin(value, self.categories)
if not isna(value[mask]).all():
raise ValueError("fill value must be in categories")
values_codes = _get_codes_for_values(value, self.categories)
indexer = np.where(codes == -1)
codes = codes.copy()
codes[indexer] = values_codes[indexer]
# If value is not a dict or Series it should be a scalar
elif is_hashable(value):
if not isna(value) and value not in self.categories:
raise ValueError("fill value must be in categories")
mask = codes == -1
if mask.any():
codes = codes.copy()
if isna(value):
codes[mask] = -1
else:
codes[mask] = self.categories.get_loc(value)
else:
raise TypeError(
f"'value' parameter must be a scalar, dict "
f"or Series, but you passed a {type(value).__name__}"
)
return self._constructor(codes, dtype=self.dtype, fastpath=True)
def take(self: _T, indexer, allow_fill: bool = False, fill_value=None) -> _T:
"""
Take elements from the Categorical.
Parameters
----------
indexer : sequence of int
The indices in `self` to take. The meaning of negative values in
`indexer` depends on the value of `allow_fill`.
allow_fill : bool, default False
How to handle negative values in `indexer`.
* False: negative values in `indices` indicate positional indices
from the right. This is similar to
:func:`numpy.take`.
* True: negative values in `indices` indicate missing values
(the default). These values are set to `fill_value`. Any other
other negative values raise a ``ValueError``.
.. versionchanged:: 1.0.0
Default value changed from ``True`` to ``False``.
fill_value : object
The value to use for `indices` that are missing (-1), when
``allow_fill=True``. This should be the category, i.e. a value
in ``self.categories``, not a code.
Returns
-------
Categorical
This Categorical will have the same categories and ordered as
`self`.
See Also
--------
Series.take : Similar method for Series.
numpy.ndarray.take : Similar method for NumPy arrays.
Examples
--------
>>> cat = pd.Categorical(['a', 'a', 'b'])
>>> cat
[a, a, b]
Categories (2, object): [a, b]
Specify ``allow_fill==False`` to have negative indices mean indexing
from the right.
>>> cat.take([0, -1, -2], allow_fill=False)
[a, b, a]
Categories (2, object): [a, b]
With ``allow_fill=True``, indices equal to ``-1`` mean "missing"
values that should be filled with the `fill_value`, which is
``np.nan`` by default.
>>> cat.take([0, -1, -1], allow_fill=True)
[a, NaN, NaN]
Categories (2, object): [a, b]
The fill value can be specified.
>>> cat.take([0, -1, -1], allow_fill=True, fill_value='a')
[a, a, a]
Categories (2, object): [a, b]
Specifying a fill value that's not in ``self.categories``
will raise a ``ValueError``.
"""
return NDArrayBackedExtensionArray.take(
self, indexer, allow_fill=allow_fill, fill_value=fill_value
)
# ------------------------------------------------------------------
# NDArrayBackedExtensionArray compat
@property
def _ndarray(self) -> np.ndarray:
return self._codes
def _from_backing_data(self, arr: np.ndarray) -> "Categorical":
return self._constructor(arr, dtype=self.dtype, fastpath=True)
# ------------------------------------------------------------------
def take_nd(self, indexer, allow_fill: bool = False, fill_value=None):
# GH#27745 deprecate alias that other EAs dont have
warn(
"Categorical.take_nd is deprecated, use Categorical.take instead",
FutureWarning,
stacklevel=2,
)
return self.take(indexer, allow_fill=allow_fill, fill_value=fill_value)
def __iter__(self):
"""
Returns an Iterator over the values of this Categorical.
"""
return iter(self._internal_get_values().tolist())
def __contains__(self, key) -> bool:
"""
Returns True if `key` is in this Categorical.
"""
# if key is a NaN, check if any NaN is in self.
if is_valid_nat_for_dtype(key, self.categories.dtype):
return self.isna().any()
return contains(self, key, container=self._codes)
def _tidy_repr(self, max_vals=10, footer=True) -> str:
"""
a short repr displaying only max_vals and an optional (but default
footer)
"""
num = max_vals // 2
head = self[:num]._get_repr(length=False, footer=False)
tail = self[-(max_vals - num) :]._get_repr(length=False, footer=False)
result = f"{head[:-1]}, ..., {tail[1:]}"
if footer:
result = f"{result}\n{self._repr_footer()}"
return str(result)
def _repr_categories(self):
"""
return the base repr for the categories
"""
max_categories = (
10
if get_option("display.max_categories") == 0
else get_option("display.max_categories")
)
from pandas.io.formats import format as fmt
if len(self.categories) > max_categories:
num = max_categories // 2
head = fmt.format_array(self.categories[:num], None)
tail = fmt.format_array(self.categories[-num:], None)
category_strs = head + ["..."] + tail
else:
category_strs = fmt.format_array(self.categories, None)
# Strip all leading spaces, which format_array adds for columns...
category_strs = [x.strip() for x in category_strs]
return category_strs
def _repr_categories_info(self) -> str:
"""
Returns a string representation of the footer.
"""
category_strs = self._repr_categories()
dtype = str(self.categories.dtype)
levheader = f"Categories ({len(self.categories)}, {dtype}): "
width, height = get_terminal_size()
max_width = get_option("display.width") or width
if console.in_ipython_frontend():
# 0 = no breaks
max_width = 0
levstring = ""
start = True
cur_col_len = len(levheader) # header
sep_len, sep = (3, " < ") if self.ordered else (2, ", ")
linesep = sep.rstrip() + "\n" # remove whitespace
for val in category_strs:
if max_width != 0 and cur_col_len + sep_len + len(val) > max_width:
levstring += linesep + (" " * (len(levheader) + 1))
cur_col_len = len(levheader) + 1 # header + a whitespace
elif not start:
levstring += sep
cur_col_len += len(val)
levstring += val
start = False
# replace to simple save space by
return levheader + "[" + levstring.replace(" < ... < ", " ... ") + "]"
def _repr_footer(self) -> str:
info = self._repr_categories_info()
return f"Length: {len(self)}\n{info}"
def _get_repr(self, length=True, na_rep="NaN", footer=True) -> str:
from pandas.io.formats import format as fmt
formatter = fmt.CategoricalFormatter(
self, length=length, na_rep=na_rep, footer=footer
)
result = formatter.to_string()
return str(result)
def __repr__(self) -> str:
"""
String representation.
"""
_maxlen = 10
if len(self._codes) > _maxlen:
result = self._tidy_repr(_maxlen)
elif len(self._codes) > 0:
result = self._get_repr(length=len(self) > _maxlen)
else:
msg = self._get_repr(length=False, footer=True).replace("\n", ", ")
result = f"[], {msg}"
return result
def _maybe_coerce_indexer(self, indexer):
"""
return an indexer coerced to the codes dtype
"""
if isinstance(indexer, np.ndarray) and indexer.dtype.kind == "i":
indexer = indexer.astype(self._codes.dtype)
return indexer
def __getitem__(self, key):
"""
Return an item.
"""
if isinstance(key, (int, np.integer)):
i = self._codes[key]
if i == -1:
return np.nan
else:
return self.categories[i]
key = check_array_indexer(self, key)
result = self._codes[key]
if result.ndim > 1:
deprecate_ndim_indexing(result)
return result
return self._constructor(result, dtype=self.dtype, fastpath=True)
def __setitem__(self, key, value):
"""
Item assignment.
Raises
------
ValueError
If (one or more) Value is not in categories or if a assigned
`Categorical` does not have the same categories
"""
value = extract_array(value, extract_numpy=True)
# require identical categories set
if isinstance(value, Categorical):
if not is_dtype_equal(self, value):
raise ValueError(
"Cannot set a Categorical with another, "
"without identical categories"
)
if not self.categories.equals(value.categories):
new_codes = recode_for_categories(
value.codes, value.categories, self.categories
)
value = Categorical.from_codes(new_codes, dtype=self.dtype)
rvalue = value if is_list_like(value) else [value]
from pandas import Index
to_add = Index(rvalue).difference(self.categories)
# no assignments of values not in categories, but it's always ok to set
# something to np.nan
if len(to_add) and not isna(to_add).all():
raise ValueError(
"Cannot setitem on a Categorical with a new "
"category, set the categories first"
)
# set by position
if isinstance(key, (int, np.integer)):
pass
# tuple of indexers (dataframe)
elif isinstance(key, tuple):
# only allow 1 dimensional slicing, but can
# in a 2-d case be passd (slice(None),....)
if len(key) == 2:
if not com.is_null_slice(key[0]):
raise AssertionError("invalid slicing for a 1-ndim categorical")
key = key[1]
elif len(key) == 1:
key = key[0]
else:
raise AssertionError("invalid slicing for a 1-ndim categorical")
# slicing in Series or Categorical
elif isinstance(key, slice):
pass
# else: array of True/False in Series or Categorical
lindexer = self.categories.get_indexer(rvalue)
lindexer = self._maybe_coerce_indexer(lindexer)
key = check_array_indexer(self, key)
self._codes[key] = lindexer
def _reverse_indexer(self) -> Dict[Hashable, np.ndarray]:
"""
Compute the inverse of a categorical, returning
a dict of categories -> indexers.
*This is an internal function*
Returns
-------
dict of categories -> indexers
Examples
--------
>>> c = pd.Categorical(list('aabca'))
>>> c
[a, a, b, c, a]
Categories (3, object): [a, b, c]
>>> c.categories
Index(['a', 'b', 'c'], dtype='object')
>>> c.codes
array([0, 0, 1, 2, 0], dtype=int8)
>>> c._reverse_indexer()
{'a': array([0, 1, 4]), 'b': array([2]), 'c': array([3])}
"""
categories = self.categories
r, counts = libalgos.groupsort_indexer(
self.codes.astype("int64"), categories.size
)
counts = counts.cumsum()
_result = (r[start:end] for start, end in zip(counts, counts[1:]))
result = dict(zip(categories, _result))
return result
# reduction ops #
def _reduce(self, name, axis=0, **kwargs):
func = getattr(self, name, None)
if func is None:
raise TypeError(f"Categorical cannot perform the operation {name}")
return func(**kwargs)
@deprecate_kwarg(old_arg_name="numeric_only", new_arg_name="skipna")
def min(self, skipna=True):
"""
The minimum value of the object.
Only ordered `Categoricals` have a minimum!
.. versionchanged:: 1.0.0
Returns an NA value on empty arrays
Raises
------
TypeError
If the `Categorical` is not `ordered`.
Returns
-------
min : the minimum of this `Categorical`
"""
self.check_for_ordered("min")
if not len(self._codes):
return self.dtype.na_value
good = self._codes != -1
if not good.all():
if skipna and good.any():
pointer = self._codes[good].min()
else:
return np.nan
else:
pointer = self._codes.min()
return self.categories[pointer]
@deprecate_kwarg(old_arg_name="numeric_only", new_arg_name="skipna")
def max(self, skipna=True):
"""
The maximum value of the object.
Only ordered `Categoricals` have a maximum!
.. versionchanged:: 1.0.0
Returns an NA value on empty arrays
Raises
------
TypeError
If the `Categorical` is not `ordered`.
Returns
-------
max : the maximum of this `Categorical`
"""
self.check_for_ordered("max")
if not len(self._codes):
return self.dtype.na_value
good = self._codes != -1
if not good.all():
if skipna and good.any():
pointer = self._codes[good].max()
else:
return np.nan
else:
pointer = self._codes.max()
return self.categories[pointer]
def mode(self, dropna=True):
"""
Returns the mode(s) of the Categorical.
Always returns `Categorical` even if only one value.
Parameters
----------
dropna : bool, default True
Don't consider counts of NaN/NaT.
.. versionadded:: 0.24.0
Returns
-------
modes : `Categorical` (sorted)
"""
codes = self._codes
if dropna:
good = self._codes != -1
codes = self._codes[good]
codes = sorted(htable.mode_int64(ensure_int64(codes), dropna))
return self._constructor(values=codes, dtype=self.dtype, fastpath=True)
def unique(self):
"""
Return the ``Categorical`` which ``categories`` and ``codes`` are
unique. Unused categories are NOT returned.
- unordered category: values and categories are sorted by appearance
order.
- ordered category: values are sorted by appearance order, categories
keeps existing order.
Returns
-------
unique values : ``Categorical``
See Also
--------
pandas.unique
CategoricalIndex.unique
Series.unique
Examples
--------
An unordered Categorical will return categories in the
order of appearance.
>>> pd.Categorical(list("baabc")).unique()
[b, a, c]
Categories (3, object): [b, a, c]
>>> pd.Categorical(list("baabc"), categories=list("abc")).unique()
[b, a, c]
Categories (3, object): [b, a, c]
An ordered Categorical preserves the category ordering.
>>> pd.Categorical(
... list("baabc"), categories=list("abc"), ordered=True
... ).unique()
[b, a, c]
Categories (3, object): [a < b < c]
"""
# unlike np.unique, unique1d does not sort
unique_codes = unique1d(self.codes)
cat = self.copy()
# keep nan in codes
cat._codes = unique_codes
# exclude nan from indexer for categories
take_codes = unique_codes[unique_codes != -1]
if self.ordered:
take_codes = np.sort(take_codes)
return cat.set_categories(cat.categories.take(take_codes))
def _values_for_factorize(self):
codes = self.codes.astype("int64")
return codes, -1
@classmethod
def _from_factorized(cls, uniques, original):
return original._constructor(
original.categories.take(uniques), dtype=original.dtype
)
def equals(self, other):
"""
Returns True if categorical arrays are equal.
Parameters
----------
other : `Categorical`
Returns
-------
bool
"""
if self.is_dtype_equal(other):
if self.categories.equals(other.categories):
# fastpath to avoid re-coding
other_codes = other._codes
else:
other_codes = recode_for_categories(
other.codes, other.categories, self.categories
)
return np.array_equal(self._codes, other_codes)
return False
def is_dtype_equal(self, other):
"""
Returns True if categoricals are the same dtype
same categories, and same ordered
Parameters
----------
other : Categorical
Returns
-------
bool
"""
try:
return hash(self.dtype) == hash(other.dtype)
except (AttributeError, TypeError):
return False
def describe(self):
"""
Describes this Categorical
Returns
-------
description: `DataFrame`
A dataframe with frequency and counts by category.
"""
counts = self.value_counts(dropna=False)
freqs = counts / float(counts.sum())
from pandas.core.reshape.concat import concat
result = concat([counts, freqs], axis=1)
result.columns = ["counts", "freqs"]
result.index.name = "categories"
return result
# Implement the ExtensionArray interface
@property
def _can_hold_na(self):
return True
@classmethod
def _concat_same_type(self, to_concat):
from pandas.core.dtypes.concat import union_categoricals
return union_categoricals(to_concat)
def isin(self, values):
"""
Check whether `values` are contained in Categorical.
Return a boolean NumPy Array showing whether each element in
the Categorical matches an element in the passed sequence of
`values` exactly.
Parameters
----------
values : set or list-like
The sequence of values to test. Passing in a single string will
raise a ``TypeError``. Instead, turn a single string into a
list of one element.
Returns
-------
isin : numpy.ndarray (bool dtype)
Raises
------
TypeError
* If `values` is not a set or list-like
See Also
--------
pandas.Series.isin : Equivalent method on Series.
Examples
--------
>>> s = pd.Categorical(['lama', 'cow', 'lama', 'beetle', 'lama',
... 'hippo'])
>>> s.isin(['cow', 'lama'])
array([ True, True, True, False, True, False])
Passing a single string as ``s.isin('lama')`` will raise an error. Use
a list of one element instead:
>>> s.isin(['lama'])
array([ True, False, True, False, True, False])
"""
if not is_list_like(values):
values_type = type(values).__name__
raise TypeError(
"only list-like objects are allowed to be passed "
f"to isin(), you passed a [{values_type}]"
)
values = sanitize_array(values, None, None)
null_mask = np.asarray(isna(values))
code_values = self.categories.get_indexer(values)
code_values = code_values[null_mask | (code_values >= 0)]
return algorithms.isin(self.codes, code_values)
def replace(self, to_replace, value, inplace: bool = False):
"""
Replaces all instances of one value with another
Parameters
----------
to_replace: object
The value to be replaced
value: object
The value to replace it with
inplace: bool
Whether the operation is done in-place
Returns
-------
None if inplace is True, otherwise the new Categorical after replacement
Examples
--------
>>> s = pd.Categorical([1, 2, 1, 3])
>>> s.replace(1, 3)
[3, 2, 3, 3]
Categories (2, int64): [2, 3]
"""
inplace = validate_bool_kwarg(inplace, "inplace")
cat = self if inplace else self.copy()
# build a dict of (to replace -> value) pairs
if is_list_like(to_replace):
# if to_replace is list-like and value is scalar
replace_dict = {replace_value: value for replace_value in to_replace}
else:
# if both to_replace and value are scalar
replace_dict = {to_replace: value}
# other cases, like if both to_replace and value are list-like or if
# to_replace is a dict, are handled separately in NDFrame
for replace_value, new_value in replace_dict.items():
if new_value == replace_value:
continue
if replace_value in cat.categories:
if isna(new_value):
cat.remove_categories(replace_value, inplace=True)
continue
categories = cat.categories.tolist()
index = categories.index(replace_value)
if new_value in cat.categories:
value_index = categories.index(new_value)
cat._codes[cat._codes == index] = value_index
cat.remove_categories(replace_value, inplace=True)
else:
categories[index] = new_value
cat.rename_categories(categories, inplace=True)
if not inplace:
return cat
# The Series.cat accessor
@delegate_names(
delegate=Categorical, accessors=["categories", "ordered"], typ="property"
)
@delegate_names(
delegate=Categorical,
accessors=[
"rename_categories",
"reorder_categories",
"add_categories",
"remove_categories",
"remove_unused_categories",
"set_categories",
"as_ordered",
"as_unordered",
],
typ="method",
)
class CategoricalAccessor(PandasDelegate, PandasObject, NoNewAttributesMixin):
"""
Accessor object for categorical properties of the Series values.
Be aware that assigning to `categories` is a inplace operation, while all
methods return new categorical data per default (but can be called with
`inplace=True`).
Parameters
----------
data : Series or CategoricalIndex
Examples
--------
>>> s = pd.Series(list("abbccc")).astype("category")
>>> s
0 a
1 b
2 b
3 c
4 c
5 c
dtype: category
Categories (3, object): [a, b, c]
>>> s.cat.categories
Index(['a', 'b', 'c'], dtype='object')
>>> s.cat.rename_categories(list("cba"))
0 c
1 b
2 b
3 a
4 a
5 a
dtype: category
Categories (3, object): [c, b, a]
>>> s.cat.reorder_categories(list("cba"))
0 a
1 b
2 b
3 c
4 c
5 c
dtype: category
Categories (3, object): [c, b, a]
>>> s.cat.add_categories(["d", "e"])
0 a
1 b
2 b
3 c
4 c
5 c
dtype: category
Categories (5, object): [a, b, c, d, e]
>>> s.cat.remove_categories(["a", "c"])
0 NaN
1 b
2 b
3 NaN
4 NaN
5 NaN
dtype: category
Categories (1, object): [b]
>>> s1 = s.cat.add_categories(["d", "e"])
>>> s1.cat.remove_unused_categories()
0 a
1 b
2 b
3 c
4 c
5 c
dtype: category
Categories (3, object): [a, b, c]
>>> s.cat.set_categories(list("abcde"))
0 a
1 b
2 b
3 c
4 c
5 c
dtype: category
Categories (5, object): [a, b, c, d, e]
>>> s.cat.as_ordered()
0 a
1 b
2 b
3 c
4 c
5 c
dtype: category
Categories (3, object): [a < b < c]
>>> s.cat.as_unordered()
0 a
1 b
2 b
3 c
4 c
5 c
dtype: category
Categories (3, object): [a, b, c]
"""
def __init__(self, data):
self._validate(data)
self._parent = data.values
self._index = data.index
self._name = data.name
self._freeze()
@staticmethod
def _validate(data):
if not is_categorical_dtype(data.dtype):
raise AttributeError("Can only use .cat accessor with a 'category' dtype")
def _delegate_property_get(self, name):
return getattr(self._parent, name)
def _delegate_property_set(self, name, new_values):
return setattr(self._parent, name, new_values)
@property
def codes(self):
"""
Return Series of codes as well as the index.
"""
from pandas import Series
return Series(self._parent.codes, index=self._index)
def _delegate_method(self, name, *args, **kwargs):
from pandas import Series
method = getattr(self._parent, name)
res = method(*args, **kwargs)
if res is not None:
return Series(res, index=self._index, name=self._name)
# utility routines
def _get_codes_for_values(values, categories):
"""
utility routine to turn values into codes given the specified categories
"""
dtype_equal = is_dtype_equal(values.dtype, categories.dtype)
if is_extension_array_dtype(categories.dtype) and is_object_dtype(values):
# Support inferring the correct extension dtype from an array of
# scalar objects. e.g.
# Categorical(array[Period, Period], categories=PeriodIndex(...))
cls = categories.dtype.construct_array_type()
values = maybe_cast_to_extension_array(cls, values)
if not isinstance(values, cls):
# exception raised in _from_sequence
values = ensure_object(values)
categories = ensure_object(categories)
elif not dtype_equal:
values = ensure_object(values)
categories = ensure_object(categories)
hash_klass, vals = _get_data_algo(values)
_, cats = _get_data_algo(categories)
t = hash_klass(len(cats))
t.map_locations(cats)
return coerce_indexer_dtype(t.lookup(vals), cats)
def recode_for_categories(codes: np.ndarray, old_categories, new_categories):
"""
Convert a set of codes for to a new set of categories
Parameters
----------
codes : np.ndarray
old_categories, new_categories : Index
Returns
-------
new_codes : np.ndarray[np.int64]
Examples
--------
>>> old_cat = pd.Index(['b', 'a', 'c'])
>>> new_cat = pd.Index(['a', 'b'])
>>> codes = np.array([0, 1, 1, 2])
>>> recode_for_categories(codes, old_cat, new_cat)
array([ 1, 0, 0, -1], dtype=int8)
"""
if len(old_categories) == 0:
# All null anyway, so just retain the nulls
return codes.copy()
elif new_categories.equals(old_categories):
# Same categories, so no need to actually recode
return codes.copy()
indexer = coerce_indexer_dtype(
new_categories.get_indexer(old_categories), new_categories
)
new_codes = take_1d(indexer, codes.copy(), fill_value=-1)
return new_codes
def _convert_to_list_like(list_like):
if hasattr(list_like, "dtype"):
return list_like
if isinstance(list_like, list):
return list_like
if is_sequence(list_like) or isinstance(list_like, tuple) or is_iterator(list_like):
return list(list_like)
elif is_scalar(list_like):
return [list_like]
else:
# TODO: is this reached?
return [list_like]
def factorize_from_iterable(values):
"""
Factorize an input `values` into `categories` and `codes`. Preserves
categorical dtype in `categories`.
*This is an internal function*
Parameters
----------
values : list-like
Returns
-------
codes : ndarray
categories : Index
If `values` has a categorical dtype, then `categories` is
a CategoricalIndex keeping the categories and order of `values`.
"""
if not is_list_like(values):
raise TypeError("Input must be list-like")
if is_categorical_dtype(values):
values = extract_array(values)
# The Categorical we want to build has the same categories
# as values but its codes are by def [0, ..., len(n_categories) - 1]
cat_codes = np.arange(len(values.categories), dtype=values.codes.dtype)
categories = Categorical.from_codes(cat_codes, dtype=values.dtype)
codes = values.codes
else:
# The value of ordered is irrelevant since we don't use cat as such,
# but only the resulting categories, the order of which is independent
# from ordered. Set ordered to False as default. See GH #15457
cat = Categorical(values, ordered=False)
categories = cat.categories
codes = cat.codes
return codes, categories
def factorize_from_iterables(iterables):
"""
A higher-level wrapper over `factorize_from_iterable`.
*This is an internal function*
Parameters
----------
iterables : list-like of list-likes
Returns
-------
codes_list : list of ndarrays
categories_list : list of Indexes
Notes
-----
See `factorize_from_iterable` for more info.
"""
if len(iterables) == 0:
# For consistency, it should return a list of 2 lists.
return [[], []]
return map(list, zip(*(factorize_from_iterable(it) for it in iterables)))
| BugsInPy/BugsInPy/temp/projects/pandas/bug-9-fixed/pandas/pandas/core/arrays/categorical.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-9-buggy/pandas/pandas/core/arrays/categorical.py |
pandas-bug-140 | """
Define the SeriesGroupBy and DataFrameGroupBy
classes that hold the groupby interfaces (and some implementations).
These are user facing as the result of the ``df.groupby(...)`` operations,
which here returns a DataFrameGroupBy object.
"""
from collections import OrderedDict, abc, namedtuple
import copy
import functools
from functools import partial
from textwrap import dedent
import typing
from typing import Any, Callable, FrozenSet, Sequence, Type, Union
import warnings
import numpy as np
from pandas._libs import Timestamp, lib
from pandas.compat import PY36
from pandas.errors import AbstractMethodError
from pandas.util._decorators import Appender, Substitution
from pandas.core.dtypes.cast import (
maybe_convert_objects,
maybe_downcast_numeric,
maybe_downcast_to_dtype,
)
from pandas.core.dtypes.common import (
ensure_int64,
ensure_platform_int,
is_bool,
is_datetimelike,
is_dict_like,
is_integer_dtype,
is_interval_dtype,
is_list_like,
is_numeric_dtype,
is_object_dtype,
is_scalar,
)
from pandas.core.dtypes.missing import _isna_ndarraylike, isna, notna
from pandas._typing import FrameOrSeries
import pandas.core.algorithms as algorithms
from pandas.core.base import DataError, SpecificationError
import pandas.core.common as com
from pandas.core.frame import DataFrame
from pandas.core.generic import ABCDataFrame, ABCSeries, NDFrame, _shared_docs
from pandas.core.groupby import base
from pandas.core.groupby.groupby import (
GroupBy,
_apply_docs,
_transform_template,
groupby,
)
from pandas.core.index import Index, MultiIndex, _all_indexes_same
import pandas.core.indexes.base as ibase
from pandas.core.internals import BlockManager, make_block
from pandas.core.series import Series
from pandas.plotting import boxplot_frame_groupby
NamedAgg = namedtuple("NamedAgg", ["column", "aggfunc"])
# TODO(typing) the return value on this callable should be any *scalar*.
AggScalar = Union[str, Callable[..., Any]]
# TODO: validate types on ScalarResult and move to _typing
# Blocked from using by https://github.com/python/mypy/issues/1484
# See note at _mangle_lambda_list
ScalarResult = typing.TypeVar("ScalarResult")
def generate_property(name: str, klass: Type[FrameOrSeries]):
"""
Create a property for a GroupBy subclass to dispatch to DataFrame/Series.
Parameters
----------
name : str
klass : {DataFrame, Series}
Returns
-------
property
"""
def prop(self):
return self._make_wrapper(name)
parent_method = getattr(klass, name)
prop.__doc__ = parent_method.__doc__ or ""
prop.__name__ = name
return property(prop)
def pin_whitelisted_properties(klass: Type[FrameOrSeries], whitelist: FrozenSet[str]):
"""
Create GroupBy member defs for DataFrame/Series names in a whitelist.
Parameters
----------
klass : DataFrame or Series class
class where members are defined.
whitelist : frozenset[str]
Set of names of klass methods to be constructed
Returns
-------
class decorator
Notes
-----
Since we don't want to override methods explicitly defined in the
base class, any such name is skipped.
"""
def pinner(cls):
for name in whitelist:
if hasattr(cls, name):
# don't override anything that was explicitly defined
# in the base class
continue
prop = generate_property(name, klass)
setattr(cls, name, prop)
return cls
return pinner
class NDFrameGroupBy(GroupBy):
def _iterate_slices(self):
if self.axis == 0:
# kludge
if self._selection is None:
slice_axis = self.obj.columns
else:
slice_axis = self._selection_list
slicer = lambda x: self.obj[x]
else:
slice_axis = self.obj.index
slicer = self.obj.xs
for val in slice_axis:
if val in self.exclusions:
continue
yield val, slicer(val)
def _cython_agg_general(self, how, alt=None, numeric_only=True, min_count=-1):
new_items, new_blocks = self._cython_agg_blocks(
how, alt=alt, numeric_only=numeric_only, min_count=min_count
)
return self._wrap_agged_blocks(new_items, new_blocks)
_block_agg_axis = 0
def _cython_agg_blocks(self, how, alt=None, numeric_only=True, min_count=-1):
# TODO: the actual managing of mgr_locs is a PITA
# here, it should happen via BlockManager.combine
data, agg_axis = self._get_data_to_aggregate()
if numeric_only:
data = data.get_numeric_data(copy=False)
new_blocks = []
new_items = []
deleted_items = []
no_result = object()
for block in data.blocks:
# Avoid inheriting result from earlier in the loop
result = no_result
locs = block.mgr_locs.as_array
try:
result, _ = self.grouper.aggregate(
block.values, how, axis=agg_axis, min_count=min_count
)
except NotImplementedError:
# generally if we have numeric_only=False
# and non-applicable functions
# try to python agg
if alt is None:
# we cannot perform the operation
# in an alternate way, exclude the block
deleted_items.append(locs)
continue
# call our grouper again with only this block
obj = self.obj[data.items[locs]]
s = groupby(obj, self.grouper)
try:
result = s.aggregate(lambda x: alt(x, axis=self.axis))
except TypeError:
# we may have an exception in trying to aggregate
# continue and exclude the block
deleted_items.append(locs)
continue
finally:
if result is not no_result:
# see if we can cast the block back to the original dtype
result = maybe_downcast_numeric(result, block.dtype)
newb = block.make_block(result)
new_items.append(locs)
new_blocks.append(newb)
if len(new_blocks) == 0:
raise DataError("No numeric types to aggregate")
# reset the locs in the blocks to correspond to our
# current ordering
indexer = np.concatenate(new_items)
new_items = data.items.take(np.sort(indexer))
if len(deleted_items):
# we need to adjust the indexer to account for the
# items we have removed
# really should be done in internals :<
deleted = np.concatenate(deleted_items)
ai = np.arange(len(data))
mask = np.zeros(len(data))
mask[deleted] = 1
indexer = (ai - mask.cumsum())[indexer]
offset = 0
for b in new_blocks:
loc = len(b.mgr_locs)
b.mgr_locs = indexer[offset : (offset + loc)]
offset += loc
return new_items, new_blocks
def aggregate(self, func, *args, **kwargs):
_level = kwargs.pop("_level", None)
relabeling = func is None and _is_multi_agg_with_relabel(**kwargs)
if relabeling:
func, columns, order = _normalize_keyword_aggregation(kwargs)
kwargs = {}
elif func is None:
# nicer error message
raise TypeError("Must provide 'func' or tuples of '(column, aggfunc).")
func = _maybe_mangle_lambdas(func)
result, how = self._aggregate(func, _level=_level, *args, **kwargs)
if how is None:
return result
if result is None:
# grouper specific aggregations
if self.grouper.nkeys > 1:
return self._python_agg_general(func, *args, **kwargs)
elif args or kwargs:
result = self._aggregate_generic(func, *args, **kwargs)
else:
# try to treat as if we are passing a list
try:
result = self._aggregate_multiple_funcs(
[func], _level=_level, _axis=self.axis
)
except Exception:
result = self._aggregate_generic(func)
else:
result.columns = Index(
result.columns.levels[0], name=self._selected_obj.columns.name
)
if not self.as_index:
self._insert_inaxis_grouper_inplace(result)
result.index = np.arange(len(result))
if relabeling:
# used reordered index of columns
result = result.iloc[:, order]
result.columns = columns
return result._convert(datetime=True)
agg = aggregate
def _aggregate_generic(self, func, *args, **kwargs):
if self.grouper.nkeys != 1:
raise AssertionError("Number of keys must be 1")
axis = self.axis
obj = self._obj_with_exclusions
result = OrderedDict()
if axis != obj._info_axis_number:
try:
for name, data in self:
result[name] = self._try_cast(func(data, *args, **kwargs), data)
except Exception:
return self._aggregate_item_by_item(func, *args, **kwargs)
else:
for name in self.indices:
try:
data = self.get_group(name, obj=obj)
result[name] = self._try_cast(func(data, *args, **kwargs), data)
except Exception:
wrapper = lambda x: func(x, *args, **kwargs)
result[name] = data.apply(wrapper, axis=axis)
return self._wrap_generic_output(result, obj)
def _wrap_aggregated_output(self, output, names=None):
raise AbstractMethodError(self)
def _aggregate_item_by_item(self, func, *args, **kwargs):
# only for axis==0
obj = self._obj_with_exclusions
result = OrderedDict()
cannot_agg = []
errors = None
for item in obj:
data = obj[item]
colg = SeriesGroupBy(data, selection=item, grouper=self.grouper)
try:
cast = self._transform_should_cast(func)
result[item] = colg.aggregate(func, *args, **kwargs)
if cast:
result[item] = self._try_cast(result[item], data)
except ValueError as err:
if "Must produce aggregated value" in str(err):
# raised in _aggregate_named, handle at higher level
# see test_apply_with_mutated_index
raise
cannot_agg.append(item)
continue
except TypeError as e:
cannot_agg.append(item)
errors = e
continue
result_columns = obj.columns
if cannot_agg:
result_columns = result_columns.drop(cannot_agg)
# GH6337
if not len(result_columns) and errors is not None:
raise errors
return DataFrame(result, columns=result_columns)
def _decide_output_index(self, output, labels):
if len(output) == len(labels):
output_keys = labels
else:
output_keys = sorted(output)
try:
output_keys.sort()
except TypeError:
pass
if isinstance(labels, MultiIndex):
output_keys = MultiIndex.from_tuples(output_keys, names=labels.names)
return output_keys
def _wrap_applied_output(self, keys, values, not_indexed_same=False):
if len(keys) == 0:
return DataFrame(index=keys)
key_names = self.grouper.names
# GH12824.
def first_not_none(values):
try:
return next(com.not_none(*values))
except StopIteration:
return None
v = first_not_none(values)
if v is None:
# GH9684. If all values are None, then this will throw an error.
# We'd prefer it return an empty dataframe.
return DataFrame()
elif isinstance(v, DataFrame):
return self._concat_objects(keys, values, not_indexed_same=not_indexed_same)
elif self.grouper.groupings is not None:
if len(self.grouper.groupings) > 1:
key_index = self.grouper.result_index
else:
ping = self.grouper.groupings[0]
if len(keys) == ping.ngroups:
key_index = ping.group_index
key_index.name = key_names[0]
key_lookup = Index(keys)
indexer = key_lookup.get_indexer(key_index)
# reorder the values
values = [values[i] for i in indexer]
else:
key_index = Index(keys, name=key_names[0])
# don't use the key indexer
if not self.as_index:
key_index = None
# make Nones an empty object
v = first_not_none(values)
if v is None:
return DataFrame()
elif isinstance(v, NDFrame):
values = [
x if x is not None else v._constructor(**v._construct_axes_dict())
for x in values
]
v = values[0]
if isinstance(v, (np.ndarray, Index, Series)):
if isinstance(v, Series):
applied_index = self._selected_obj._get_axis(self.axis)
all_indexed_same = _all_indexes_same([x.index for x in values])
singular_series = len(values) == 1 and applied_index.nlevels == 1
# GH3596
# provide a reduction (Frame -> Series) if groups are
# unique
if self.squeeze:
# assign the name to this series
if singular_series:
values[0].name = keys[0]
# GH2893
# we have series in the values array, we want to
# produce a series:
# if any of the sub-series are not indexed the same
# OR we don't have a multi-index and we have only a
# single values
return self._concat_objects(
keys, values, not_indexed_same=not_indexed_same
)
# still a series
# path added as of GH 5545
elif all_indexed_same:
from pandas.core.reshape.concat import concat
return concat(values)
if not all_indexed_same:
# GH 8467
return self._concat_objects(keys, values, not_indexed_same=True)
try:
if self.axis == 0:
# GH6124 if the list of Series have a consistent name,
# then propagate that name to the result.
index = v.index.copy()
if index.name is None:
# Only propagate the series name to the result
# if all series have a consistent name. If the
# series do not have a consistent name, do
# nothing.
names = {v.name for v in values}
if len(names) == 1:
index.name = list(names)[0]
# normally use vstack as its faster than concat
# and if we have mi-columns
if (
isinstance(v.index, MultiIndex)
or key_index is None
or isinstance(key_index, MultiIndex)
):
stacked_values = np.vstack([np.asarray(v) for v in values])
result = DataFrame(
stacked_values, index=key_index, columns=index
)
else:
# GH5788 instead of stacking; concat gets the
# dtypes correct
from pandas.core.reshape.concat import concat
result = concat(
values,
keys=key_index,
names=key_index.names,
axis=self.axis,
).unstack()
result.columns = index
else:
stacked_values = np.vstack([np.asarray(v) for v in values])
result = DataFrame(
stacked_values.T, index=v.index, columns=key_index
)
except (ValueError, AttributeError):
# GH1738: values is list of arrays of unequal lengths fall
# through to the outer else caluse
return Series(values, index=key_index, name=self._selection_name)
# if we have date/time like in the original, then coerce dates
# as we are stacking can easily have object dtypes here
so = self._selected_obj
if so.ndim == 2 and so.dtypes.apply(is_datetimelike).any():
result = _recast_datetimelike_result(result)
else:
result = result._convert(datetime=True)
return self._reindex_output(result)
# values are not series or array-like but scalars
else:
# only coerce dates if we find at least 1 datetime
coerce = any(isinstance(x, Timestamp) for x in values)
# self._selection_name not passed through to Series as the
# result should not take the name of original selection
# of columns
return Series(values, index=key_index)._convert(
datetime=True, coerce=coerce
)
else:
# Handle cases like BinGrouper
return self._concat_objects(keys, values, not_indexed_same=not_indexed_same)
def _transform_general(self, func, *args, **kwargs):
from pandas.core.reshape.concat import concat
applied = []
obj = self._obj_with_exclusions
gen = self.grouper.get_iterator(obj, axis=self.axis)
fast_path, slow_path = self._define_paths(func, *args, **kwargs)
path = None
for name, group in gen:
object.__setattr__(group, "name", name)
if path is None:
# Try slow path and fast path.
try:
path, res = self._choose_path(fast_path, slow_path, group)
except TypeError:
return self._transform_item_by_item(obj, fast_path)
except ValueError:
msg = "transform must return a scalar value for each group"
raise ValueError(msg)
else:
res = path(group)
if isinstance(res, Series):
# we need to broadcast across the
# other dimension; this will preserve dtypes
# GH14457
if not np.prod(group.shape):
continue
elif res.index.is_(obj.index):
r = concat([res] * len(group.columns), axis=1)
r.columns = group.columns
r.index = group.index
else:
r = DataFrame(
np.concatenate([res.values] * len(group.index)).reshape(
group.shape
),
columns=group.columns,
index=group.index,
)
applied.append(r)
else:
applied.append(res)
concat_index = obj.columns if self.axis == 0 else obj.index
other_axis = 1 if self.axis == 0 else 0 # switches between 0 & 1
concatenated = concat(applied, axis=self.axis, verify_integrity=False)
concatenated = concatenated.reindex(concat_index, axis=other_axis, copy=False)
return self._set_result_index_ordered(concatenated)
@Substitution(klass="DataFrame", selected="")
@Appender(_transform_template)
def transform(self, func, *args, **kwargs):
# optimized transforms
func = self._get_cython_func(func) or func
if isinstance(func, str):
if not (func in base.transform_kernel_whitelist):
msg = "'{func}' is not a valid function name for transform(name)"
raise ValueError(msg.format(func=func))
if func in base.cythonized_kernels:
# cythonized transformation or canned "reduction+broadcast"
return getattr(self, func)(*args, **kwargs)
else:
# If func is a reduction, we need to broadcast the
# result to the whole group. Compute func result
# and deal with possible broadcasting below.
result = getattr(self, func)(*args, **kwargs)
else:
return self._transform_general(func, *args, **kwargs)
# a reduction transform
if not isinstance(result, DataFrame):
return self._transform_general(func, *args, **kwargs)
obj = self._obj_with_exclusions
# nuisance columns
if not result.columns.equals(obj.columns):
return self._transform_general(func, *args, **kwargs)
return self._transform_fast(result, obj, func)
def _transform_fast(self, result, obj, func_nm):
"""
Fast transform path for aggregations
"""
# if there were groups with no observations (Categorical only?)
# try casting data to original dtype
cast = self._transform_should_cast(func_nm)
# for each col, reshape to to size of original frame
# by take operation
ids, _, ngroup = self.grouper.group_info
output = []
for i, _ in enumerate(result.columns):
res = algorithms.take_1d(result.iloc[:, i].values, ids)
if cast:
res = self._try_cast(res, obj.iloc[:, i])
output.append(res)
return DataFrame._from_arrays(output, columns=result.columns, index=obj.index)
def _define_paths(self, func, *args, **kwargs):
if isinstance(func, str):
fast_path = lambda group: getattr(group, func)(*args, **kwargs)
slow_path = lambda group: group.apply(
lambda x: getattr(x, func)(*args, **kwargs), axis=self.axis
)
else:
fast_path = lambda group: func(group, *args, **kwargs)
slow_path = lambda group: group.apply(
lambda x: func(x, *args, **kwargs), axis=self.axis
)
return fast_path, slow_path
def _choose_path(self, fast_path, slow_path, group):
path = slow_path
res = slow_path(group)
# if we make it here, test if we can use the fast path
try:
res_fast = fast_path(group)
except Exception:
# Hard to know ex-ante what exceptions `fast_path` might raise
return path, res
# verify fast path does not change columns (and names), otherwise
# its results cannot be joined with those of the slow path
if not isinstance(res_fast, DataFrame):
return path, res
if not res_fast.columns.equals(group.columns):
return path, res
if res_fast.equals(res):
path = fast_path
return path, res
def _transform_item_by_item(self, obj, wrapper):
# iterate through columns
output = {}
inds = []
for i, col in enumerate(obj):
try:
output[col] = self[col].transform(wrapper)
inds.append(i)
except Exception:
pass
if len(output) == 0:
raise TypeError("Transform function invalid for data types")
columns = obj.columns
if len(output) < len(obj.columns):
columns = columns.take(inds)
return DataFrame(output, index=obj.index, columns=columns)
def filter(self, func, dropna=True, *args, **kwargs):
"""
Return a copy of a DataFrame excluding elements from groups that
do not satisfy the boolean criterion specified by func.
Parameters
----------
f : function
Function to apply to each subframe. Should return True or False.
dropna : Drop groups that do not pass the filter. True by default;
If False, groups that evaluate False are filled with NaNs.
Returns
-------
filtered : DataFrame
Notes
-----
Each subframe is endowed the attribute 'name' in case you need to know
which group you are working on.
Examples
--------
>>> df = pd.DataFrame({'A' : ['foo', 'bar', 'foo', 'bar',
... 'foo', 'bar'],
... 'B' : [1, 2, 3, 4, 5, 6],
... 'C' : [2.0, 5., 8., 1., 2., 9.]})
>>> grouped = df.groupby('A')
>>> grouped.filter(lambda x: x['B'].mean() > 3.)
A B C
1 bar 2 5.0
3 bar 4 1.0
5 bar 6 9.0
"""
indices = []
obj = self._selected_obj
gen = self.grouper.get_iterator(obj, axis=self.axis)
for name, group in gen:
object.__setattr__(group, "name", name)
res = func(group, *args, **kwargs)
try:
res = res.squeeze()
except AttributeError: # allow e.g., scalars and frames to pass
pass
# interpret the result of the filter
if is_bool(res) or (is_scalar(res) and isna(res)):
if res and notna(res):
indices.append(self._get_index(name))
else:
# non scalars aren't allowed
raise TypeError(
"filter function returned a %s, "
"but expected a scalar bool" % type(res).__name__
)
return self._apply_filter(indices, dropna)
@pin_whitelisted_properties(Series, base.series_apply_whitelist)
class SeriesGroupBy(GroupBy):
_apply_whitelist = base.series_apply_whitelist
@property
def _selection_name(self):
"""
since we are a series, we by definition only have
a single name, but may be the result of a selection or
the name of our object
"""
if self._selection is None:
return self.obj.name
else:
return self._selection
_agg_see_also_doc = dedent(
"""
See Also
--------
pandas.Series.groupby.apply
pandas.Series.groupby.transform
pandas.Series.aggregate
"""
)
_agg_examples_doc = dedent(
"""
Examples
--------
>>> s = pd.Series([1, 2, 3, 4])
>>> s
0 1
1 2
2 3
3 4
dtype: int64
>>> s.groupby([1, 1, 2, 2]).min()
1 1
2 3
dtype: int64
>>> s.groupby([1, 1, 2, 2]).agg('min')
1 1
2 3
dtype: int64
>>> s.groupby([1, 1, 2, 2]).agg(['min', 'max'])
min max
1 1 2
2 3 4
The output column names can be controlled by passing
the desired column names and aggregations as keyword arguments.
>>> s.groupby([1, 1, 2, 2]).agg(
... minimum='min',
... maximum='max',
... )
minimum maximum
1 1 2
2 3 4
"""
)
@Appender(
_apply_docs["template"].format(
input="series", examples=_apply_docs["series_examples"]
)
)
def apply(self, func, *args, **kwargs):
return super().apply(func, *args, **kwargs)
@Substitution(
see_also=_agg_see_also_doc,
examples=_agg_examples_doc,
versionadded="",
klass="Series",
axis="",
)
@Appender(_shared_docs["aggregate"])
def aggregate(self, func=None, *args, **kwargs):
_level = kwargs.pop("_level", None)
relabeling = func is None
columns = None
no_arg_message = "Must provide 'func' or named aggregation **kwargs."
if relabeling:
columns = list(kwargs)
if not PY36:
# sort for 3.5 and earlier
columns = list(sorted(columns))
func = [kwargs[col] for col in columns]
kwargs = {}
if not columns:
raise TypeError(no_arg_message)
if isinstance(func, str):
return getattr(self, func)(*args, **kwargs)
if isinstance(func, abc.Iterable):
# Catch instances of lists / tuples
# but not the class list / tuple itself.
func = _maybe_mangle_lambdas(func)
ret = self._aggregate_multiple_funcs(func, (_level or 0) + 1)
if relabeling:
ret.columns = columns
else:
cyfunc = self._get_cython_func(func)
if cyfunc and not args and not kwargs:
return getattr(self, cyfunc)()
if self.grouper.nkeys > 1:
return self._python_agg_general(func, *args, **kwargs)
try:
return self._python_agg_general(func, *args, **kwargs)
except Exception:
result = self._aggregate_named(func, *args, **kwargs)
index = Index(sorted(result), name=self.grouper.names[0])
ret = Series(result, index=index)
if not self.as_index: # pragma: no cover
print("Warning, ignoring as_index=True")
# _level handled at higher
if not _level and isinstance(ret, dict):
from pandas import concat
ret = concat(ret, axis=1)
return ret
agg = aggregate
def _aggregate_multiple_funcs(self, arg, _level):
if isinstance(arg, dict):
# show the deprecation, but only if we
# have not shown a higher level one
# GH 15931
if isinstance(self._selected_obj, Series) and _level <= 1:
msg = dedent(
"""\
using a dict on a Series for aggregation
is deprecated and will be removed in a future version. Use \
named aggregation instead.
>>> grouper.agg(name_1=func_1, name_2=func_2)
"""
)
warnings.warn(msg, FutureWarning, stacklevel=3)
columns = list(arg.keys())
arg = arg.items()
elif any(isinstance(x, (tuple, list)) for x in arg):
arg = [(x, x) if not isinstance(x, (tuple, list)) else x for x in arg]
# indicated column order
columns = next(zip(*arg))
else:
# list of functions / function names
columns = []
for f in arg:
columns.append(com.get_callable_name(f) or f)
arg = zip(columns, arg)
results = OrderedDict()
for name, func in arg:
obj = self
if name in results:
raise SpecificationError(
"Function names must be unique, found multiple named "
"{}".format(name)
)
# reset the cache so that we
# only include the named selection
if name in self._selected_obj:
obj = copy.copy(obj)
obj._reset_cache()
obj._selection = name
results[name] = obj.aggregate(func)
if any(isinstance(x, DataFrame) for x in results.values()):
# let higher level handle
if _level:
return results
return DataFrame(results, columns=columns)
def _wrap_output(self, output, index, names=None):
""" common agg/transform wrapping logic """
output = output[self._selection_name]
if names is not None:
return DataFrame(output, index=index, columns=names)
else:
name = self._selection_name
if name is None:
name = self._selected_obj.name
return Series(output, index=index, name=name)
def _wrap_aggregated_output(self, output, names=None):
result = self._wrap_output(
output=output, index=self.grouper.result_index, names=names
)
return self._reindex_output(result)._convert(datetime=True)
def _wrap_transformed_output(self, output, names=None):
return self._wrap_output(output=output, index=self.obj.index, names=names)
def _wrap_applied_output(self, keys, values, not_indexed_same=False):
if len(keys) == 0:
# GH #6265
return Series([], name=self._selection_name, index=keys)
def _get_index():
if self.grouper.nkeys > 1:
index = MultiIndex.from_tuples(keys, names=self.grouper.names)
else:
index = Index(keys, name=self.grouper.names[0])
return index
if isinstance(values[0], dict):
# GH #823 #24880
index = _get_index()
result = self._reindex_output(DataFrame(values, index=index))
# if self.observed is False,
# keep all-NaN rows created while re-indexing
result = result.stack(dropna=self.observed)
result.name = self._selection_name
return result
if isinstance(values[0], Series):
return self._concat_objects(keys, values, not_indexed_same=not_indexed_same)
elif isinstance(values[0], DataFrame):
# possible that Series -> DataFrame by applied function
return self._concat_objects(keys, values, not_indexed_same=not_indexed_same)
else:
# GH #6265 #24880
result = Series(data=values, index=_get_index(), name=self._selection_name)
return self._reindex_output(result)
def _aggregate_named(self, func, *args, **kwargs):
result = OrderedDict()
for name, group in self:
group.name = name
output = func(group, *args, **kwargs)
if isinstance(output, (Series, Index, np.ndarray)):
raise ValueError("Must produce aggregated value")
result[name] = self._try_cast(output, group)
return result
@Substitution(klass="Series", selected="A.")
@Appender(_transform_template)
def transform(self, func, *args, **kwargs):
func = self._get_cython_func(func) or func
if isinstance(func, str):
if not (func in base.transform_kernel_whitelist):
msg = "'{func}' is not a valid function name for transform(name)"
raise ValueError(msg.format(func=func))
if func in base.cythonized_kernels:
# cythonized transform or canned "agg+broadcast"
return getattr(self, func)(*args, **kwargs)
else:
# If func is a reduction, we need to broadcast the
# result to the whole group. Compute func result
# and deal with possible broadcasting below.
return self._transform_fast(
lambda: getattr(self, func)(*args, **kwargs), func
)
# reg transform
klass = self._selected_obj.__class__
results = []
wrapper = lambda x: func(x, *args, **kwargs)
for name, group in self:
object.__setattr__(group, "name", name)
res = wrapper(group)
if isinstance(res, (ABCDataFrame, ABCSeries)):
res = res._values
indexer = self._get_index(name)
s = klass(res, indexer)
results.append(s)
# check for empty "results" to avoid concat ValueError
if results:
from pandas.core.reshape.concat import concat
result = concat(results).sort_index()
else:
result = Series()
# we will only try to coerce the result type if
# we have a numeric dtype, as these are *always* udfs
# the cython take a different path (and casting)
dtype = self._selected_obj.dtype
if is_numeric_dtype(dtype):
result = maybe_downcast_to_dtype(result, dtype)
result.name = self._selected_obj.name
result.index = self._selected_obj.index
return result
def _transform_fast(self, func, func_nm):
"""
fast version of transform, only applicable to
builtin/cythonizable functions
"""
if isinstance(func, str):
func = getattr(self, func)
ids, _, ngroup = self.grouper.group_info
cast = self._transform_should_cast(func_nm)
out = algorithms.take_1d(func()._values, ids)
if cast:
out = self._try_cast(out, self.obj)
return Series(out, index=self.obj.index, name=self.obj.name)
def filter(self, func, dropna=True, *args, **kwargs): # noqa
"""
Return a copy of a Series excluding elements from groups that
do not satisfy the boolean criterion specified by func.
Parameters
----------
func : function
To apply to each group. Should return True or False.
dropna : Drop groups that do not pass the filter. True by default;
if False, groups that evaluate False are filled with NaNs.
Examples
--------
>>> df = pd.DataFrame({'A' : ['foo', 'bar', 'foo', 'bar',
... 'foo', 'bar'],
... 'B' : [1, 2, 3, 4, 5, 6],
... 'C' : [2.0, 5., 8., 1., 2., 9.]})
>>> grouped = df.groupby('A')
>>> df.groupby('A').B.filter(lambda x: x.mean() > 3.)
1 2
3 4
5 6
Name: B, dtype: int64
Returns
-------
filtered : Series
"""
if isinstance(func, str):
wrapper = lambda x: getattr(x, func)(*args, **kwargs)
else:
wrapper = lambda x: func(x, *args, **kwargs)
# Interpret np.nan as False.
def true_and_notna(x, *args, **kwargs):
b = wrapper(x, *args, **kwargs)
return b and notna(b)
try:
indices = [
self._get_index(name) for name, group in self if true_and_notna(group)
]
except ValueError:
raise TypeError("the filter must return a boolean result")
except TypeError:
raise TypeError("the filter must return a boolean result")
filtered = self._apply_filter(indices, dropna)
return filtered
def nunique(self, dropna=True):
"""
Return number of unique elements in the group.
Returns
-------
Series
Number of unique values within each group.
"""
ids, _, _ = self.grouper.group_info
val = self.obj._internal_get_values()
# GH 27951
# temporary fix while we wait for NumPy bug 12629 to be fixed
val[isna(val)] = np.datetime64("NaT")
try:
sorter = np.lexsort((val, ids))
except TypeError: # catches object dtypes
msg = "val.dtype must be object, got {}".format(val.dtype)
assert val.dtype == object, msg
val, _ = algorithms.factorize(val, sort=False)
sorter = np.lexsort((val, ids))
_isna = lambda a: a == -1
else:
_isna = isna
ids, val = ids[sorter], val[sorter]
# group boundaries are where group ids change
# unique observations are where sorted values change
idx = np.r_[0, 1 + np.nonzero(ids[1:] != ids[:-1])[0]]
inc = np.r_[1, val[1:] != val[:-1]]
# 1st item of each group is a new unique observation
mask = _isna(val)
if dropna:
inc[idx] = 1
inc[mask] = 0
else:
inc[mask & np.r_[False, mask[:-1]]] = 0
inc[idx] = 1
out = np.add.reduceat(inc, idx).astype("int64", copy=False)
if len(ids):
# NaN/NaT group exists if the head of ids is -1,
# so remove it from res and exclude its index from idx
if ids[0] == -1:
res = out[1:]
idx = idx[np.flatnonzero(idx)]
else:
res = out
else:
res = out[1:]
ri = self.grouper.result_index
# we might have duplications among the bins
if len(res) != len(ri):
res, out = np.zeros(len(ri), dtype=out.dtype), res
res[ids[idx]] = out
return Series(res, index=ri, name=self._selection_name)
@Appender(Series.describe.__doc__)
def describe(self, **kwargs):
result = self.apply(lambda x: x.describe(**kwargs))
if self.axis == 1:
return result.T
return result.unstack()
def value_counts(
self, normalize=False, sort=True, ascending=False, bins=None, dropna=True
):
from pandas.core.reshape.tile import cut
from pandas.core.reshape.merge import _get_join_indexers
if bins is not None and not np.iterable(bins):
# scalar bins cannot be done at top level
# in a backward compatible way
return self.apply(
Series.value_counts,
normalize=normalize,
sort=sort,
ascending=ascending,
bins=bins,
)
ids, _, _ = self.grouper.group_info
val = self.obj._internal_get_values()
# groupby removes null keys from groupings
mask = ids != -1
ids, val = ids[mask], val[mask]
if bins is None:
lab, lev = algorithms.factorize(val, sort=True)
llab = lambda lab, inc: lab[inc]
else:
# lab is a Categorical with categories an IntervalIndex
lab = cut(Series(val), bins, include_lowest=True)
lev = lab.cat.categories
lab = lev.take(lab.cat.codes)
llab = lambda lab, inc: lab[inc]._multiindex.codes[-1]
if is_interval_dtype(lab):
# TODO: should we do this inside II?
sorter = np.lexsort((lab.left, lab.right, ids))
else:
sorter = np.lexsort((lab, ids))
ids, lab = ids[sorter], lab[sorter]
# group boundaries are where group ids change
idx = np.r_[0, 1 + np.nonzero(ids[1:] != ids[:-1])[0]]
# new values are where sorted labels change
lchanges = llab(lab, slice(1, None)) != llab(lab, slice(None, -1))
inc = np.r_[True, lchanges]
inc[idx] = True # group boundaries are also new values
out = np.diff(np.nonzero(np.r_[inc, True])[0]) # value counts
# num. of times each group should be repeated
rep = partial(np.repeat, repeats=np.add.reduceat(inc, idx))
# multi-index components
labels = list(map(rep, self.grouper.recons_labels)) + [llab(lab, inc)]
levels = [ping.group_index for ping in self.grouper.groupings] + [lev]
names = self.grouper.names + [self._selection_name]
if dropna:
mask = labels[-1] != -1
if mask.all():
dropna = False
else:
out, labels = out[mask], [label[mask] for label in labels]
if normalize:
out = out.astype("float")
d = np.diff(np.r_[idx, len(ids)])
if dropna:
m = ids[lab == -1]
np.add.at(d, m, -1)
acc = rep(d)[mask]
else:
acc = rep(d)
out /= acc
if sort and bins is None:
cat = ids[inc][mask] if dropna else ids[inc]
sorter = np.lexsort((out if ascending else -out, cat))
out, labels[-1] = out[sorter], labels[-1][sorter]
if bins is None:
mi = MultiIndex(
levels=levels, codes=labels, names=names, verify_integrity=False
)
if is_integer_dtype(out):
out = ensure_int64(out)
return Series(out, index=mi, name=self._selection_name)
# for compat. with libgroupby.value_counts need to ensure every
# bin is present at every index level, null filled with zeros
diff = np.zeros(len(out), dtype="bool")
for lab in labels[:-1]:
diff |= np.r_[True, lab[1:] != lab[:-1]]
ncat, nbin = diff.sum(), len(levels[-1])
left = [np.repeat(np.arange(ncat), nbin), np.tile(np.arange(nbin), ncat)]
right = [diff.cumsum() - 1, labels[-1]]
_, idx = _get_join_indexers(left, right, sort=False, how="left")
out = np.where(idx != -1, out[idx], 0)
if sort:
sorter = np.lexsort((out if ascending else -out, left[0]))
out, left[-1] = out[sorter], left[-1][sorter]
# build the multi-index w/ full levels
codes = list(map(lambda lab: np.repeat(lab[diff], nbin), labels[:-1]))
codes.append(left[-1])
mi = MultiIndex(levels=levels, codes=codes, names=names, verify_integrity=False)
if is_integer_dtype(out):
out = ensure_int64(out)
return Series(out, index=mi, name=self._selection_name)
def count(self):
"""
Compute count of group, excluding missing values.
Returns
-------
Series
Count of values within each group.
"""
ids, _, ngroups = self.grouper.group_info
val = self.obj._internal_get_values()
mask = (ids != -1) & ~isna(val)
ids = ensure_platform_int(ids)
minlength = ngroups or 0
out = np.bincount(ids[mask], minlength=minlength)
return Series(
out,
index=self.grouper.result_index,
name=self._selection_name,
dtype="int64",
)
def _apply_to_column_groupbys(self, func):
""" return a pass thru """
return func(self)
def pct_change(self, periods=1, fill_method="pad", limit=None, freq=None):
"""Calculate pct_change of each value to previous entry in group"""
# TODO: Remove this conditional when #23918 is fixed
if freq:
return self.apply(
lambda x: x.pct_change(
periods=periods, fill_method=fill_method, limit=limit, freq=freq
)
)
filled = getattr(self, fill_method)(limit=limit)
fill_grp = filled.groupby(self.grouper.labels)
shifted = fill_grp.shift(periods=periods, freq=freq)
return (filled / shifted) - 1
@pin_whitelisted_properties(DataFrame, base.dataframe_apply_whitelist)
class DataFrameGroupBy(NDFrameGroupBy):
_apply_whitelist = base.dataframe_apply_whitelist
_block_agg_axis = 1
_agg_see_also_doc = dedent(
"""
See Also
--------
pandas.DataFrame.groupby.apply
pandas.DataFrame.groupby.transform
pandas.DataFrame.aggregate
"""
)
_agg_examples_doc = dedent(
"""
Examples
--------
>>> df = pd.DataFrame({'A': [1, 1, 2, 2],
... 'B': [1, 2, 3, 4],
... 'C': np.random.randn(4)})
>>> df
A B C
0 1 1 0.362838
1 1 2 0.227877
2 2 3 1.267767
3 2 4 -0.562860
The aggregation is for each column.
>>> df.groupby('A').agg('min')
B C
A
1 1 0.227877
2 3 -0.562860
Multiple aggregations
>>> df.groupby('A').agg(['min', 'max'])
B C
min max min max
A
1 1 2 0.227877 0.362838
2 3 4 -0.562860 1.267767
Select a column for aggregation
>>> df.groupby('A').B.agg(['min', 'max'])
min max
A
1 1 2
2 3 4
Different aggregations per column
>>> df.groupby('A').agg({'B': ['min', 'max'], 'C': 'sum'})
B C
min max sum
A
1 1 2 0.590716
2 3 4 0.704907
To control the output names with different aggregations per column,
pandas supports "named aggregation"
>>> df.groupby("A").agg(
... b_min=pd.NamedAgg(column="B", aggfunc="min"),
... c_sum=pd.NamedAgg(column="C", aggfunc="sum"))
b_min c_sum
A
1 1 -1.956929
2 3 -0.322183
- The keywords are the *output* column names
- The values are tuples whose first element is the column to select
and the second element is the aggregation to apply to that column.
Pandas provides the ``pandas.NamedAgg`` namedtuple with the fields
``['column', 'aggfunc']`` to make it clearer what the arguments are.
As usual, the aggregation can be a callable or a string alias.
See :ref:`groupby.aggregate.named` for more.
"""
)
@Substitution(
see_also=_agg_see_also_doc,
examples=_agg_examples_doc,
versionadded="",
klass="DataFrame",
axis="",
)
@Appender(_shared_docs["aggregate"])
def aggregate(self, func=None, *args, **kwargs):
return super().aggregate(func, *args, **kwargs)
agg = aggregate
def _gotitem(self, key, ndim, subset=None):
"""
sub-classes to define
return a sliced object
Parameters
----------
key : string / list of selections
ndim : 1,2
requested ndim of result
subset : object, default None
subset to act on
"""
if ndim == 2:
if subset is None:
subset = self.obj
return DataFrameGroupBy(
subset,
self.grouper,
selection=key,
grouper=self.grouper,
exclusions=self.exclusions,
as_index=self.as_index,
observed=self.observed,
)
elif ndim == 1:
if subset is None:
subset = self.obj[key]
return SeriesGroupBy(
subset, selection=key, grouper=self.grouper, observed=self.observed
)
raise AssertionError("invalid ndim for _gotitem")
def _wrap_generic_output(self, result, obj):
result_index = self.grouper.levels[0]
if self.axis == 0:
return DataFrame(result, index=obj.columns, columns=result_index).T
else:
return DataFrame(result, index=obj.index, columns=result_index)
def _get_data_to_aggregate(self):
obj = self._obj_with_exclusions
if self.axis == 1:
return obj.T._data, 1
else:
return obj._data, 1
def _insert_inaxis_grouper_inplace(self, result):
# zip in reverse so we can always insert at loc 0
izip = zip(
*map(
reversed,
(
self.grouper.names,
self.grouper.get_group_levels(),
[grp.in_axis for grp in self.grouper.groupings],
),
)
)
for name, lev, in_axis in izip:
if in_axis:
result.insert(0, name, lev)
def _wrap_aggregated_output(self, output, names=None):
agg_axis = 0 if self.axis == 1 else 1
agg_labels = self._obj_with_exclusions._get_axis(agg_axis)
output_keys = self._decide_output_index(output, agg_labels)
if not self.as_index:
result = DataFrame(output, columns=output_keys)
self._insert_inaxis_grouper_inplace(result)
result = result._consolidate()
else:
index = self.grouper.result_index
result = DataFrame(output, index=index, columns=output_keys)
if self.axis == 1:
result = result.T
return self._reindex_output(result)._convert(datetime=True)
def _wrap_transformed_output(self, output, names=None):
return DataFrame(output, index=self.obj.index)
def _wrap_agged_blocks(self, items, blocks):
if not self.as_index:
index = np.arange(blocks[0].values.shape[-1])
mgr = BlockManager(blocks, [items, index])
result = DataFrame(mgr)
self._insert_inaxis_grouper_inplace(result)
result = result._consolidate()
else:
index = self.grouper.result_index
mgr = BlockManager(blocks, [items, index])
result = DataFrame(mgr)
if self.axis == 1:
result = result.T
return self._reindex_output(result)._convert(datetime=True)
def _iterate_column_groupbys(self):
for i, colname in enumerate(self._selected_obj.columns):
yield colname, SeriesGroupBy(
self._selected_obj.iloc[:, i],
selection=colname,
grouper=self.grouper,
exclusions=self.exclusions,
)
def _apply_to_column_groupbys(self, func):
from pandas.core.reshape.concat import concat
return concat(
(func(col_groupby) for _, col_groupby in self._iterate_column_groupbys()),
keys=self._selected_obj.columns,
axis=1,
)
def count(self):
"""
Compute count of group, excluding missing values.
Returns
-------
DataFrame
Count of values within each group.
"""
data, _ = self._get_data_to_aggregate()
ids, _, ngroups = self.grouper.group_info
mask = ids != -1
val = (
(mask & ~_isna_ndarraylike(np.atleast_2d(blk.get_values())))
for blk in data.blocks
)
loc = (blk.mgr_locs for blk in data.blocks)
counter = partial(lib.count_level_2d, labels=ids, max_bin=ngroups, axis=1)
blk = map(make_block, map(counter, val), loc)
return self._wrap_agged_blocks(data.items, list(blk))
def nunique(self, dropna=True):
"""
Return DataFrame with number of distinct observations per group for
each column.
.. versionadded:: 0.20.0
Parameters
----------
dropna : boolean, default True
Don't include NaN in the counts.
Returns
-------
nunique: DataFrame
Examples
--------
>>> df = pd.DataFrame({'id': ['spam', 'egg', 'egg', 'spam',
... 'ham', 'ham'],
... 'value1': [1, 5, 5, 2, 5, 5],
... 'value2': list('abbaxy')})
>>> df
id value1 value2
0 spam 1 a
1 egg 5 b
2 egg 5 b
3 spam 2 a
4 ham 5 x
5 ham 5 y
>>> df.groupby('id').nunique()
id value1 value2
id
egg 1 1 1
ham 1 1 2
spam 1 2 1
Check for rows with the same id but conflicting values:
>>> df.groupby('id').filter(lambda g: (g.nunique() > 1).any())
id value1 value2
0 spam 1 a
3 spam 2 a
4 ham 5 x
5 ham 5 y
"""
obj = self._selected_obj
def groupby_series(obj, col=None):
return SeriesGroupBy(obj, selection=col, grouper=self.grouper).nunique(
dropna=dropna
)
if isinstance(obj, Series):
results = groupby_series(obj)
else:
from pandas.core.reshape.concat import concat
results = [groupby_series(obj[col], col) for col in obj.columns]
results = concat(results, axis=1)
results.columns.names = obj.columns.names
if not self.as_index:
results.index = ibase.default_index(len(results))
return results
boxplot = boxplot_frame_groupby
def _is_multi_agg_with_relabel(**kwargs):
"""
Check whether kwargs passed to .agg look like multi-agg with relabeling.
Parameters
----------
**kwargs : dict
Returns
-------
bool
Examples
--------
>>> _is_multi_agg_with_relabel(a='max')
False
>>> _is_multi_agg_with_relabel(a_max=('a', 'max'),
... a_min=('a', 'min'))
True
>>> _is_multi_agg_with_relabel()
False
"""
return all(isinstance(v, tuple) and len(v) == 2 for v in kwargs.values()) and kwargs
def _normalize_keyword_aggregation(kwargs):
"""
Normalize user-provided "named aggregation" kwargs.
Transforms from the new ``Dict[str, NamedAgg]`` style kwargs
to the old OrderedDict[str, List[scalar]]].
Parameters
----------
kwargs : dict
Returns
-------
aggspec : dict
The transformed kwargs.
columns : List[str]
The user-provided keys.
col_idx_order : List[int]
List of columns indices.
Examples
--------
>>> _normalize_keyword_aggregation({'output': ('input', 'sum')})
(OrderedDict([('input', ['sum'])]), ('output',), [('input', 'sum')])
"""
if not PY36:
kwargs = OrderedDict(sorted(kwargs.items()))
# Normalize the aggregation functions as Dict[column, List[func]],
# process normally, then fixup the names.
# TODO(Py35): When we drop python 3.5, change this to
# defaultdict(list)
# TODO: aggspec type: typing.OrderedDict[str, List[AggScalar]]
# May be hitting https://github.com/python/mypy/issues/5958
# saying it doesn't have an attribute __name__
aggspec = OrderedDict()
order = []
columns, pairs = list(zip(*kwargs.items()))
for name, (column, aggfunc) in zip(columns, pairs):
if column in aggspec:
aggspec[column].append(aggfunc)
else:
aggspec[column] = [aggfunc]
order.append((column, com.get_callable_name(aggfunc) or aggfunc))
# uniquify aggfunc name if duplicated in order list
uniquified_order = _make_unique(order)
# GH 25719, due to aggspec will change the order of assigned columns in aggregation
# uniquified_aggspec will store uniquified order list and will compare it with order
# based on index
aggspec_order = [
(column, com.get_callable_name(aggfunc) or aggfunc)
for column, aggfuncs in aggspec.items()
for aggfunc in aggfuncs
]
uniquified_aggspec = _make_unique(aggspec_order)
# get the new indice of columns by comparison
col_idx_order = Index(uniquified_aggspec).get_indexer(uniquified_order)
return aggspec, columns, col_idx_order
def _make_unique(seq):
"""Uniquify aggfunc name of the pairs in the order list
Examples:
--------
>>> _make_unique([('a', '<lambda>'), ('a', '<lambda>'), ('b', '<lambda>')])
[('a', '<lambda>_0'), ('a', '<lambda>_1'), ('b', '<lambda>')]
"""
return [
(pair[0], "_".join([pair[1], str(seq[:i].count(pair))]))
if seq.count(pair) > 1
else pair
for i, pair in enumerate(seq)
]
# TODO: Can't use, because mypy doesn't like us setting __name__
# error: "partial[Any]" has no attribute "__name__"
# the type is:
# typing.Sequence[Callable[..., ScalarResult]]
# -> typing.Sequence[Callable[..., ScalarResult]]:
def _managle_lambda_list(aggfuncs: Sequence[Any]) -> Sequence[Any]:
"""
Possibly mangle a list of aggfuncs.
Parameters
----------
aggfuncs : Sequence
Returns
-------
mangled: list-like
A new AggSpec sequence, where lambdas have been converted
to have unique names.
Notes
-----
If just one aggfunc is passed, the name will not be mangled.
"""
if len(aggfuncs) <= 1:
# don't mangle for .agg([lambda x: .])
return aggfuncs
i = 0
mangled_aggfuncs = []
for aggfunc in aggfuncs:
if com.get_callable_name(aggfunc) == "<lambda>":
aggfunc = functools.partial(aggfunc)
aggfunc.__name__ = "<lambda_{}>".format(i)
i += 1
mangled_aggfuncs.append(aggfunc)
return mangled_aggfuncs
def _maybe_mangle_lambdas(agg_spec: Any) -> Any:
"""
Make new lambdas with unique names.
Parameters
----------
agg_spec : Any
An argument to NDFrameGroupBy.agg.
Non-dict-like `agg_spec` are pass through as is.
For dict-like `agg_spec` a new spec is returned
with name-mangled lambdas.
Returns
-------
mangled : Any
Same type as the input.
Examples
--------
>>> _maybe_mangle_lambdas('sum')
'sum'
>>> _maybe_mangle_lambdas([lambda: 1, lambda: 2]) # doctest: +SKIP
[<function __main__.<lambda_0>,
<function pandas...._make_lambda.<locals>.f(*args, **kwargs)>]
"""
is_dict = is_dict_like(agg_spec)
if not (is_dict or is_list_like(agg_spec)):
return agg_spec
mangled_aggspec = type(agg_spec)() # dict or OrderdDict
if is_dict:
for key, aggfuncs in agg_spec.items():
if is_list_like(aggfuncs) and not is_dict_like(aggfuncs):
mangled_aggfuncs = _managle_lambda_list(aggfuncs)
else:
mangled_aggfuncs = aggfuncs
mangled_aggspec[key] = mangled_aggfuncs
else:
mangled_aggspec = _managle_lambda_list(agg_spec)
return mangled_aggspec
def _recast_datetimelike_result(result: DataFrame) -> DataFrame:
"""
If we have date/time like in the original, then coerce dates
as we are stacking can easily have object dtypes here.
Parameters
----------
result : DataFrame
Returns
-------
DataFrame
Notes
-----
- Assumes Groupby._selected_obj has ndim==2 and at least one
datetimelike column
"""
result = result.copy()
obj_cols = [
idx for idx in range(len(result.columns)) if is_object_dtype(result.dtypes[idx])
]
# See GH#26285
for n in obj_cols:
converted = maybe_convert_objects(
result.iloc[:, n].values, convert_numeric=False
)
result.iloc[:, n] = converted
return result
"""
Define the SeriesGroupBy and DataFrameGroupBy
classes that hold the groupby interfaces (and some implementations).
These are user facing as the result of the ``df.groupby(...)`` operations,
which here returns a DataFrameGroupBy object.
"""
from collections import OrderedDict, abc, namedtuple
import copy
import functools
from functools import partial
from textwrap import dedent
import typing
from typing import Any, Callable, FrozenSet, Sequence, Type, Union
import warnings
import numpy as np
from pandas._libs import Timestamp, lib
from pandas.compat import PY36
from pandas.errors import AbstractMethodError
from pandas.util._decorators import Appender, Substitution
from pandas.core.dtypes.cast import (
maybe_convert_objects,
maybe_downcast_numeric,
maybe_downcast_to_dtype,
)
from pandas.core.dtypes.common import (
ensure_int64,
ensure_platform_int,
is_bool,
is_datetimelike,
is_dict_like,
is_integer_dtype,
is_interval_dtype,
is_list_like,
is_numeric_dtype,
is_object_dtype,
is_scalar,
)
from pandas.core.dtypes.missing import _isna_ndarraylike, isna, notna
from pandas._typing import FrameOrSeries
import pandas.core.algorithms as algorithms
from pandas.core.base import DataError, SpecificationError
import pandas.core.common as com
from pandas.core.frame import DataFrame
from pandas.core.generic import ABCDataFrame, ABCSeries, NDFrame, _shared_docs
from pandas.core.groupby import base
from pandas.core.groupby.groupby import (
GroupBy,
_apply_docs,
_transform_template,
groupby,
)
from pandas.core.index import Index, MultiIndex, _all_indexes_same
import pandas.core.indexes.base as ibase
from pandas.core.internals import BlockManager, make_block
from pandas.core.series import Series
from pandas.plotting import boxplot_frame_groupby
NamedAgg = namedtuple("NamedAgg", ["column", "aggfunc"])
# TODO(typing) the return value on this callable should be any *scalar*.
AggScalar = Union[str, Callable[..., Any]]
# TODO: validate types on ScalarResult and move to _typing
# Blocked from using by https://github.com/python/mypy/issues/1484
# See note at _mangle_lambda_list
ScalarResult = typing.TypeVar("ScalarResult")
def generate_property(name: str, klass: Type[FrameOrSeries]):
"""
Create a property for a GroupBy subclass to dispatch to DataFrame/Series.
Parameters
----------
name : str
klass : {DataFrame, Series}
Returns
-------
property
"""
def prop(self):
return self._make_wrapper(name)
parent_method = getattr(klass, name)
prop.__doc__ = parent_method.__doc__ or ""
prop.__name__ = name
return property(prop)
def pin_whitelisted_properties(klass: Type[FrameOrSeries], whitelist: FrozenSet[str]):
"""
Create GroupBy member defs for DataFrame/Series names in a whitelist.
Parameters
----------
klass : DataFrame or Series class
class where members are defined.
whitelist : frozenset[str]
Set of names of klass methods to be constructed
Returns
-------
class decorator
Notes
-----
Since we don't want to override methods explicitly defined in the
base class, any such name is skipped.
"""
def pinner(cls):
for name in whitelist:
if hasattr(cls, name):
# don't override anything that was explicitly defined
# in the base class
continue
prop = generate_property(name, klass)
setattr(cls, name, prop)
return cls
return pinner
class NDFrameGroupBy(GroupBy):
def _iterate_slices(self):
if self.axis == 0:
# kludge
if self._selection is None:
slice_axis = self.obj.columns
else:
slice_axis = self._selection_list
slicer = lambda x: self.obj[x]
else:
slice_axis = self.obj.index
slicer = self.obj.xs
for val in slice_axis:
if val in self.exclusions:
continue
yield val, slicer(val)
def _cython_agg_general(self, how, alt=None, numeric_only=True, min_count=-1):
new_items, new_blocks = self._cython_agg_blocks(
how, alt=alt, numeric_only=numeric_only, min_count=min_count
)
return self._wrap_agged_blocks(new_items, new_blocks)
_block_agg_axis = 0
def _cython_agg_blocks(self, how, alt=None, numeric_only=True, min_count=-1):
# TODO: the actual managing of mgr_locs is a PITA
# here, it should happen via BlockManager.combine
data, agg_axis = self._get_data_to_aggregate()
if numeric_only:
data = data.get_numeric_data(copy=False)
new_blocks = []
new_items = []
deleted_items = []
no_result = object()
for block in data.blocks:
# Avoid inheriting result from earlier in the loop
result = no_result
locs = block.mgr_locs.as_array
try:
result, _ = self.grouper.aggregate(
block.values, how, axis=agg_axis, min_count=min_count
)
except NotImplementedError:
# generally if we have numeric_only=False
# and non-applicable functions
# try to python agg
if alt is None:
# we cannot perform the operation
# in an alternate way, exclude the block
deleted_items.append(locs)
continue
# call our grouper again with only this block
obj = self.obj[data.items[locs]]
s = groupby(obj, self.grouper)
try:
result = s.aggregate(lambda x: alt(x, axis=self.axis))
except TypeError:
# we may have an exception in trying to aggregate
# continue and exclude the block
deleted_items.append(locs)
continue
finally:
if result is not no_result:
# see if we can cast the block back to the original dtype
result = maybe_downcast_numeric(result, block.dtype)
newb = block.make_block(result)
new_items.append(locs)
new_blocks.append(newb)
if len(new_blocks) == 0:
raise DataError("No numeric types to aggregate")
# reset the locs in the blocks to correspond to our
# current ordering
indexer = np.concatenate(new_items)
new_items = data.items.take(np.sort(indexer))
if len(deleted_items):
# we need to adjust the indexer to account for the
# items we have removed
# really should be done in internals :<
deleted = np.concatenate(deleted_items)
ai = np.arange(len(data))
mask = np.zeros(len(data))
mask[deleted] = 1
indexer = (ai - mask.cumsum())[indexer]
offset = 0
for b in new_blocks:
loc = len(b.mgr_locs)
b.mgr_locs = indexer[offset : (offset + loc)]
offset += loc
return new_items, new_blocks
def aggregate(self, func, *args, **kwargs):
_level = kwargs.pop("_level", None)
relabeling = func is None and _is_multi_agg_with_relabel(**kwargs)
if relabeling:
func, columns, order = _normalize_keyword_aggregation(kwargs)
kwargs = {}
elif func is None:
# nicer error message
raise TypeError("Must provide 'func' or tuples of '(column, aggfunc).")
func = _maybe_mangle_lambdas(func)
result, how = self._aggregate(func, _level=_level, *args, **kwargs)
if how is None:
return result
if result is None:
# grouper specific aggregations
if self.grouper.nkeys > 1:
return self._python_agg_general(func, *args, **kwargs)
elif args or kwargs:
result = self._aggregate_generic(func, *args, **kwargs)
else:
# try to treat as if we are passing a list
try:
result = self._aggregate_multiple_funcs(
[func], _level=_level, _axis=self.axis
)
except Exception:
result = self._aggregate_generic(func)
else:
result.columns = Index(
result.columns.levels[0], name=self._selected_obj.columns.name
)
if not self.as_index:
self._insert_inaxis_grouper_inplace(result)
result.index = np.arange(len(result))
if relabeling:
# used reordered index of columns
result = result.iloc[:, order]
result.columns = columns
return result._convert(datetime=True)
agg = aggregate
def _aggregate_generic(self, func, *args, **kwargs):
if self.grouper.nkeys != 1:
raise AssertionError("Number of keys must be 1")
axis = self.axis
obj = self._obj_with_exclusions
result = OrderedDict()
if axis != obj._info_axis_number:
try:
for name, data in self:
result[name] = self._try_cast(func(data, *args, **kwargs), data)
except Exception:
return self._aggregate_item_by_item(func, *args, **kwargs)
else:
for name in self.indices:
try:
data = self.get_group(name, obj=obj)
result[name] = self._try_cast(func(data, *args, **kwargs), data)
except Exception:
wrapper = lambda x: func(x, *args, **kwargs)
result[name] = data.apply(wrapper, axis=axis)
return self._wrap_generic_output(result, obj)
def _wrap_aggregated_output(self, output, names=None):
raise AbstractMethodError(self)
def _aggregate_item_by_item(self, func, *args, **kwargs):
# only for axis==0
obj = self._obj_with_exclusions
result = OrderedDict()
cannot_agg = []
errors = None
for item in obj:
data = obj[item]
colg = SeriesGroupBy(data, selection=item, grouper=self.grouper)
try:
cast = self._transform_should_cast(func)
result[item] = colg.aggregate(func, *args, **kwargs)
if cast:
result[item] = self._try_cast(result[item], data)
except ValueError as err:
if "Must produce aggregated value" in str(err):
# raised in _aggregate_named, handle at higher level
# see test_apply_with_mutated_index
raise
cannot_agg.append(item)
continue
except TypeError as e:
cannot_agg.append(item)
errors = e
continue
result_columns = obj.columns
if cannot_agg:
result_columns = result_columns.drop(cannot_agg)
# GH6337
if not len(result_columns) and errors is not None:
raise errors
return DataFrame(result, columns=result_columns)
def _decide_output_index(self, output, labels):
if len(output) == len(labels):
output_keys = labels
else:
output_keys = sorted(output)
try:
output_keys.sort()
except TypeError:
pass
if isinstance(labels, MultiIndex):
output_keys = MultiIndex.from_tuples(output_keys, names=labels.names)
return output_keys
def _wrap_applied_output(self, keys, values, not_indexed_same=False):
if len(keys) == 0:
return DataFrame(index=keys)
key_names = self.grouper.names
# GH12824.
def first_not_none(values):
try:
return next(com.not_none(*values))
except StopIteration:
return None
v = first_not_none(values)
if v is None:
# GH9684. If all values are None, then this will throw an error.
# We'd prefer it return an empty dataframe.
return DataFrame()
elif isinstance(v, DataFrame):
return self._concat_objects(keys, values, not_indexed_same=not_indexed_same)
elif self.grouper.groupings is not None:
if len(self.grouper.groupings) > 1:
key_index = self.grouper.result_index
else:
ping = self.grouper.groupings[0]
if len(keys) == ping.ngroups:
key_index = ping.group_index
key_index.name = key_names[0]
key_lookup = Index(keys)
indexer = key_lookup.get_indexer(key_index)
# reorder the values
values = [values[i] for i in indexer]
else:
key_index = Index(keys, name=key_names[0])
# don't use the key indexer
if not self.as_index:
key_index = None
# make Nones an empty object
v = first_not_none(values)
if v is None:
return DataFrame()
elif isinstance(v, NDFrame):
values = [
x if x is not None else v._constructor(**v._construct_axes_dict())
for x in values
]
v = values[0]
if isinstance(v, (np.ndarray, Index, Series)):
if isinstance(v, Series):
applied_index = self._selected_obj._get_axis(self.axis)
all_indexed_same = _all_indexes_same([x.index for x in values])
singular_series = len(values) == 1 and applied_index.nlevels == 1
# GH3596
# provide a reduction (Frame -> Series) if groups are
# unique
if self.squeeze:
# assign the name to this series
if singular_series:
values[0].name = keys[0]
# GH2893
# we have series in the values array, we want to
# produce a series:
# if any of the sub-series are not indexed the same
# OR we don't have a multi-index and we have only a
# single values
return self._concat_objects(
keys, values, not_indexed_same=not_indexed_same
)
# still a series
# path added as of GH 5545
elif all_indexed_same:
from pandas.core.reshape.concat import concat
return concat(values)
if not all_indexed_same:
# GH 8467
return self._concat_objects(keys, values, not_indexed_same=True)
try:
if self.axis == 0:
# GH6124 if the list of Series have a consistent name,
# then propagate that name to the result.
index = v.index.copy()
if index.name is None:
# Only propagate the series name to the result
# if all series have a consistent name. If the
# series do not have a consistent name, do
# nothing.
names = {v.name for v in values}
if len(names) == 1:
index.name = list(names)[0]
# normally use vstack as its faster than concat
# and if we have mi-columns
if (
isinstance(v.index, MultiIndex)
or key_index is None
or isinstance(key_index, MultiIndex)
):
stacked_values = np.vstack([np.asarray(v) for v in values])
result = DataFrame(
stacked_values, index=key_index, columns=index
)
else:
# GH5788 instead of stacking; concat gets the
# dtypes correct
from pandas.core.reshape.concat import concat
result = concat(
values,
keys=key_index,
names=key_index.names,
axis=self.axis,
).unstack()
result.columns = index
else:
stacked_values = np.vstack([np.asarray(v) for v in values])
result = DataFrame(
stacked_values.T, index=v.index, columns=key_index
)
except (ValueError, AttributeError):
# GH1738: values is list of arrays of unequal lengths fall
# through to the outer else caluse
return Series(values, index=key_index, name=self._selection_name)
# if we have date/time like in the original, then coerce dates
# as we are stacking can easily have object dtypes here
so = self._selected_obj
if so.ndim == 2 and so.dtypes.apply(is_datetimelike).any():
result = _recast_datetimelike_result(result)
else:
result = result._convert(datetime=True)
return self._reindex_output(result)
# values are not series or array-like but scalars
else:
# only coerce dates if we find at least 1 datetime
coerce = any(isinstance(x, Timestamp) for x in values)
# self._selection_name not passed through to Series as the
# result should not take the name of original selection
# of columns
return Series(values, index=key_index)._convert(
datetime=True, coerce=coerce
)
else:
# Handle cases like BinGrouper
return self._concat_objects(keys, values, not_indexed_same=not_indexed_same)
def _transform_general(self, func, *args, **kwargs):
from pandas.core.reshape.concat import concat
applied = []
obj = self._obj_with_exclusions
gen = self.grouper.get_iterator(obj, axis=self.axis)
fast_path, slow_path = self._define_paths(func, *args, **kwargs)
path = None
for name, group in gen:
object.__setattr__(group, "name", name)
if path is None:
# Try slow path and fast path.
try:
path, res = self._choose_path(fast_path, slow_path, group)
except TypeError:
return self._transform_item_by_item(obj, fast_path)
except ValueError:
msg = "transform must return a scalar value for each group"
raise ValueError(msg)
else:
res = path(group)
if isinstance(res, Series):
# we need to broadcast across the
# other dimension; this will preserve dtypes
# GH14457
if not np.prod(group.shape):
continue
elif res.index.is_(obj.index):
r = concat([res] * len(group.columns), axis=1)
r.columns = group.columns
r.index = group.index
else:
r = DataFrame(
np.concatenate([res.values] * len(group.index)).reshape(
group.shape
),
columns=group.columns,
index=group.index,
)
applied.append(r)
else:
applied.append(res)
concat_index = obj.columns if self.axis == 0 else obj.index
other_axis = 1 if self.axis == 0 else 0 # switches between 0 & 1
concatenated = concat(applied, axis=self.axis, verify_integrity=False)
concatenated = concatenated.reindex(concat_index, axis=other_axis, copy=False)
return self._set_result_index_ordered(concatenated)
@Substitution(klass="DataFrame", selected="")
@Appender(_transform_template)
def transform(self, func, *args, **kwargs):
# optimized transforms
func = self._get_cython_func(func) or func
if isinstance(func, str):
if not (func in base.transform_kernel_whitelist):
msg = "'{func}' is not a valid function name for transform(name)"
raise ValueError(msg.format(func=func))
if func in base.cythonized_kernels:
# cythonized transformation or canned "reduction+broadcast"
return getattr(self, func)(*args, **kwargs)
else:
# If func is a reduction, we need to broadcast the
# result to the whole group. Compute func result
# and deal with possible broadcasting below.
result = getattr(self, func)(*args, **kwargs)
else:
return self._transform_general(func, *args, **kwargs)
# a reduction transform
if not isinstance(result, DataFrame):
return self._transform_general(func, *args, **kwargs)
obj = self._obj_with_exclusions
# nuisance columns
if not result.columns.equals(obj.columns):
return self._transform_general(func, *args, **kwargs)
return self._transform_fast(result, obj, func)
def _transform_fast(self, result, obj, func_nm):
"""
Fast transform path for aggregations
"""
# if there were groups with no observations (Categorical only?)
# try casting data to original dtype
cast = self._transform_should_cast(func_nm)
# for each col, reshape to to size of original frame
# by take operation
ids, _, ngroup = self.grouper.group_info
output = []
for i, _ in enumerate(result.columns):
res = algorithms.take_1d(result.iloc[:, i].values, ids)
if cast:
res = self._try_cast(res, obj.iloc[:, i])
output.append(res)
return DataFrame._from_arrays(output, columns=result.columns, index=obj.index)
def _define_paths(self, func, *args, **kwargs):
if isinstance(func, str):
fast_path = lambda group: getattr(group, func)(*args, **kwargs)
slow_path = lambda group: group.apply(
lambda x: getattr(x, func)(*args, **kwargs), axis=self.axis
)
else:
fast_path = lambda group: func(group, *args, **kwargs)
slow_path = lambda group: group.apply(
lambda x: func(x, *args, **kwargs), axis=self.axis
)
return fast_path, slow_path
def _choose_path(self, fast_path, slow_path, group):
path = slow_path
res = slow_path(group)
# if we make it here, test if we can use the fast path
try:
res_fast = fast_path(group)
except Exception:
# Hard to know ex-ante what exceptions `fast_path` might raise
return path, res
# verify fast path does not change columns (and names), otherwise
# its results cannot be joined with those of the slow path
if not isinstance(res_fast, DataFrame):
return path, res
if not res_fast.columns.equals(group.columns):
return path, res
if res_fast.equals(res):
path = fast_path
return path, res
def _transform_item_by_item(self, obj, wrapper):
# iterate through columns
output = {}
inds = []
for i, col in enumerate(obj):
try:
output[col] = self[col].transform(wrapper)
inds.append(i)
except Exception:
pass
if len(output) == 0:
raise TypeError("Transform function invalid for data types")
columns = obj.columns
if len(output) < len(obj.columns):
columns = columns.take(inds)
return DataFrame(output, index=obj.index, columns=columns)
def filter(self, func, dropna=True, *args, **kwargs):
"""
Return a copy of a DataFrame excluding elements from groups that
do not satisfy the boolean criterion specified by func.
Parameters
----------
f : function
Function to apply to each subframe. Should return True or False.
dropna : Drop groups that do not pass the filter. True by default;
If False, groups that evaluate False are filled with NaNs.
Returns
-------
filtered : DataFrame
Notes
-----
Each subframe is endowed the attribute 'name' in case you need to know
which group you are working on.
Examples
--------
>>> df = pd.DataFrame({'A' : ['foo', 'bar', 'foo', 'bar',
... 'foo', 'bar'],
... 'B' : [1, 2, 3, 4, 5, 6],
... 'C' : [2.0, 5., 8., 1., 2., 9.]})
>>> grouped = df.groupby('A')
>>> grouped.filter(lambda x: x['B'].mean() > 3.)
A B C
1 bar 2 5.0
3 bar 4 1.0
5 bar 6 9.0
"""
indices = []
obj = self._selected_obj
gen = self.grouper.get_iterator(obj, axis=self.axis)
for name, group in gen:
object.__setattr__(group, "name", name)
res = func(group, *args, **kwargs)
try:
res = res.squeeze()
except AttributeError: # allow e.g., scalars and frames to pass
pass
# interpret the result of the filter
if is_bool(res) or (is_scalar(res) and isna(res)):
if res and notna(res):
indices.append(self._get_index(name))
else:
# non scalars aren't allowed
raise TypeError(
"filter function returned a %s, "
"but expected a scalar bool" % type(res).__name__
)
return self._apply_filter(indices, dropna)
@pin_whitelisted_properties(Series, base.series_apply_whitelist)
class SeriesGroupBy(GroupBy):
_apply_whitelist = base.series_apply_whitelist
@property
def _selection_name(self):
"""
since we are a series, we by definition only have
a single name, but may be the result of a selection or
the name of our object
"""
if self._selection is None:
return self.obj.name
else:
return self._selection
_agg_see_also_doc = dedent(
"""
See Also
--------
pandas.Series.groupby.apply
pandas.Series.groupby.transform
pandas.Series.aggregate
"""
)
_agg_examples_doc = dedent(
"""
Examples
--------
>>> s = pd.Series([1, 2, 3, 4])
>>> s
0 1
1 2
2 3
3 4
dtype: int64
>>> s.groupby([1, 1, 2, 2]).min()
1 1
2 3
dtype: int64
>>> s.groupby([1, 1, 2, 2]).agg('min')
1 1
2 3
dtype: int64
>>> s.groupby([1, 1, 2, 2]).agg(['min', 'max'])
min max
1 1 2
2 3 4
The output column names can be controlled by passing
the desired column names and aggregations as keyword arguments.
>>> s.groupby([1, 1, 2, 2]).agg(
... minimum='min',
... maximum='max',
... )
minimum maximum
1 1 2
2 3 4
"""
)
@Appender(
_apply_docs["template"].format(
input="series", examples=_apply_docs["series_examples"]
)
)
def apply(self, func, *args, **kwargs):
return super().apply(func, *args, **kwargs)
@Substitution(
see_also=_agg_see_also_doc,
examples=_agg_examples_doc,
versionadded="",
klass="Series",
axis="",
)
@Appender(_shared_docs["aggregate"])
def aggregate(self, func=None, *args, **kwargs):
_level = kwargs.pop("_level", None)
relabeling = func is None
columns = None
no_arg_message = "Must provide 'func' or named aggregation **kwargs."
if relabeling:
columns = list(kwargs)
if not PY36:
# sort for 3.5 and earlier
columns = list(sorted(columns))
func = [kwargs[col] for col in columns]
kwargs = {}
if not columns:
raise TypeError(no_arg_message)
if isinstance(func, str):
return getattr(self, func)(*args, **kwargs)
if isinstance(func, abc.Iterable):
# Catch instances of lists / tuples
# but not the class list / tuple itself.
func = _maybe_mangle_lambdas(func)
ret = self._aggregate_multiple_funcs(func, (_level or 0) + 1)
if relabeling:
ret.columns = columns
else:
cyfunc = self._get_cython_func(func)
if cyfunc and not args and not kwargs:
return getattr(self, cyfunc)()
if self.grouper.nkeys > 1:
return self._python_agg_general(func, *args, **kwargs)
try:
return self._python_agg_general(func, *args, **kwargs)
except Exception:
result = self._aggregate_named(func, *args, **kwargs)
index = Index(sorted(result), name=self.grouper.names[0])
ret = Series(result, index=index)
if not self.as_index: # pragma: no cover
print("Warning, ignoring as_index=True")
# _level handled at higher
if not _level and isinstance(ret, dict):
from pandas import concat
ret = concat(ret, axis=1)
return ret
agg = aggregate
def _aggregate_multiple_funcs(self, arg, _level):
if isinstance(arg, dict):
# show the deprecation, but only if we
# have not shown a higher level one
# GH 15931
if isinstance(self._selected_obj, Series) and _level <= 1:
msg = dedent(
"""\
using a dict on a Series for aggregation
is deprecated and will be removed in a future version. Use \
named aggregation instead.
>>> grouper.agg(name_1=func_1, name_2=func_2)
"""
)
warnings.warn(msg, FutureWarning, stacklevel=3)
columns = list(arg.keys())
arg = arg.items()
elif any(isinstance(x, (tuple, list)) for x in arg):
arg = [(x, x) if not isinstance(x, (tuple, list)) else x for x in arg]
# indicated column order
columns = next(zip(*arg))
else:
# list of functions / function names
columns = []
for f in arg:
columns.append(com.get_callable_name(f) or f)
arg = zip(columns, arg)
results = OrderedDict()
for name, func in arg:
obj = self
if name in results:
raise SpecificationError(
"Function names must be unique, found multiple named "
"{}".format(name)
)
# reset the cache so that we
# only include the named selection
if name in self._selected_obj:
obj = copy.copy(obj)
obj._reset_cache()
obj._selection = name
results[name] = obj.aggregate(func)
if any(isinstance(x, DataFrame) for x in results.values()):
# let higher level handle
if _level:
return results
return DataFrame(results, columns=columns)
def _wrap_output(self, output, index, names=None):
""" common agg/transform wrapping logic """
output = output[self._selection_name]
if names is not None:
return DataFrame(output, index=index, columns=names)
else:
name = self._selection_name
if name is None:
name = self._selected_obj.name
return Series(output, index=index, name=name)
def _wrap_aggregated_output(self, output, names=None):
result = self._wrap_output(
output=output, index=self.grouper.result_index, names=names
)
return self._reindex_output(result)._convert(datetime=True)
def _wrap_transformed_output(self, output, names=None):
return self._wrap_output(output=output, index=self.obj.index, names=names)
def _wrap_applied_output(self, keys, values, not_indexed_same=False):
if len(keys) == 0:
# GH #6265
return Series([], name=self._selection_name, index=keys)
def _get_index():
if self.grouper.nkeys > 1:
index = MultiIndex.from_tuples(keys, names=self.grouper.names)
else:
index = Index(keys, name=self.grouper.names[0])
return index
if isinstance(values[0], dict):
# GH #823 #24880
index = _get_index()
result = self._reindex_output(DataFrame(values, index=index))
# if self.observed is False,
# keep all-NaN rows created while re-indexing
result = result.stack(dropna=self.observed)
result.name = self._selection_name
return result
if isinstance(values[0], Series):
return self._concat_objects(keys, values, not_indexed_same=not_indexed_same)
elif isinstance(values[0], DataFrame):
# possible that Series -> DataFrame by applied function
return self._concat_objects(keys, values, not_indexed_same=not_indexed_same)
else:
# GH #6265 #24880
result = Series(data=values, index=_get_index(), name=self._selection_name)
return self._reindex_output(result)
def _aggregate_named(self, func, *args, **kwargs):
result = OrderedDict()
for name, group in self:
group.name = name
output = func(group, *args, **kwargs)
if isinstance(output, (Series, Index, np.ndarray)):
raise ValueError("Must produce aggregated value")
result[name] = self._try_cast(output, group)
return result
@Substitution(klass="Series", selected="A.")
@Appender(_transform_template)
def transform(self, func, *args, **kwargs):
func = self._get_cython_func(func) or func
if isinstance(func, str):
if not (func in base.transform_kernel_whitelist):
msg = "'{func}' is not a valid function name for transform(name)"
raise ValueError(msg.format(func=func))
if func in base.cythonized_kernels:
# cythonized transform or canned "agg+broadcast"
return getattr(self, func)(*args, **kwargs)
else:
# If func is a reduction, we need to broadcast the
# result to the whole group. Compute func result
# and deal with possible broadcasting below.
return self._transform_fast(
lambda: getattr(self, func)(*args, **kwargs), func
)
# reg transform
klass = self._selected_obj.__class__
results = []
wrapper = lambda x: func(x, *args, **kwargs)
for name, group in self:
object.__setattr__(group, "name", name)
res = wrapper(group)
if isinstance(res, (ABCDataFrame, ABCSeries)):
res = res._values
indexer = self._get_index(name)
s = klass(res, indexer)
results.append(s)
# check for empty "results" to avoid concat ValueError
if results:
from pandas.core.reshape.concat import concat
result = concat(results).sort_index()
else:
result = Series()
# we will only try to coerce the result type if
# we have a numeric dtype, as these are *always* udfs
# the cython take a different path (and casting)
dtype = self._selected_obj.dtype
if is_numeric_dtype(dtype):
result = maybe_downcast_to_dtype(result, dtype)
result.name = self._selected_obj.name
result.index = self._selected_obj.index
return result
def _transform_fast(self, func, func_nm):
"""
fast version of transform, only applicable to
builtin/cythonizable functions
"""
if isinstance(func, str):
func = getattr(self, func)
ids, _, ngroup = self.grouper.group_info
cast = self._transform_should_cast(func_nm)
out = algorithms.take_1d(func()._values, ids)
if cast:
out = self._try_cast(out, self.obj)
return Series(out, index=self.obj.index, name=self.obj.name)
def filter(self, func, dropna=True, *args, **kwargs): # noqa
"""
Return a copy of a Series excluding elements from groups that
do not satisfy the boolean criterion specified by func.
Parameters
----------
func : function
To apply to each group. Should return True or False.
dropna : Drop groups that do not pass the filter. True by default;
if False, groups that evaluate False are filled with NaNs.
Examples
--------
>>> df = pd.DataFrame({'A' : ['foo', 'bar', 'foo', 'bar',
... 'foo', 'bar'],
... 'B' : [1, 2, 3, 4, 5, 6],
... 'C' : [2.0, 5., 8., 1., 2., 9.]})
>>> grouped = df.groupby('A')
>>> df.groupby('A').B.filter(lambda x: x.mean() > 3.)
1 2
3 4
5 6
Name: B, dtype: int64
Returns
-------
filtered : Series
"""
if isinstance(func, str):
wrapper = lambda x: getattr(x, func)(*args, **kwargs)
else:
wrapper = lambda x: func(x, *args, **kwargs)
# Interpret np.nan as False.
def true_and_notna(x, *args, **kwargs):
b = wrapper(x, *args, **kwargs)
return b and notna(b)
try:
indices = [
self._get_index(name) for name, group in self if true_and_notna(group)
]
except ValueError:
raise TypeError("the filter must return a boolean result")
except TypeError:
raise TypeError("the filter must return a boolean result")
filtered = self._apply_filter(indices, dropna)
return filtered
def nunique(self, dropna=True):
"""
Return number of unique elements in the group.
Returns
-------
Series
Number of unique values within each group.
"""
ids, _, _ = self.grouper.group_info
val = self.obj._internal_get_values()
# GH 27951
# temporary fix while we wait for NumPy bug 12629 to be fixed
val[isna(val)] = np.datetime64("NaT")
try:
sorter = np.lexsort((val, ids))
except TypeError: # catches object dtypes
msg = "val.dtype must be object, got {}".format(val.dtype)
assert val.dtype == object, msg
val, _ = algorithms.factorize(val, sort=False)
sorter = np.lexsort((val, ids))
_isna = lambda a: a == -1
else:
_isna = isna
ids, val = ids[sorter], val[sorter]
# group boundaries are where group ids change
# unique observations are where sorted values change
idx = np.r_[0, 1 + np.nonzero(ids[1:] != ids[:-1])[0]]
inc = np.r_[1, val[1:] != val[:-1]]
# 1st item of each group is a new unique observation
mask = _isna(val)
if dropna:
inc[idx] = 1
inc[mask] = 0
else:
inc[mask & np.r_[False, mask[:-1]]] = 0
inc[idx] = 1
out = np.add.reduceat(inc, idx).astype("int64", copy=False)
if len(ids):
# NaN/NaT group exists if the head of ids is -1,
# so remove it from res and exclude its index from idx
if ids[0] == -1:
res = out[1:]
idx = idx[np.flatnonzero(idx)]
else:
res = out
else:
res = out[1:]
ri = self.grouper.result_index
# we might have duplications among the bins
if len(res) != len(ri):
res, out = np.zeros(len(ri), dtype=out.dtype), res
res[ids[idx]] = out
return Series(res, index=ri, name=self._selection_name)
@Appender(Series.describe.__doc__)
def describe(self, **kwargs):
result = self.apply(lambda x: x.describe(**kwargs))
if self.axis == 1:
return result.T
return result.unstack()
def value_counts(
self, normalize=False, sort=True, ascending=False, bins=None, dropna=True
):
from pandas.core.reshape.tile import cut
from pandas.core.reshape.merge import _get_join_indexers
if bins is not None and not np.iterable(bins):
# scalar bins cannot be done at top level
# in a backward compatible way
return self.apply(
Series.value_counts,
normalize=normalize,
sort=sort,
ascending=ascending,
bins=bins,
)
ids, _, _ = self.grouper.group_info
val = self.obj._internal_get_values()
# groupby removes null keys from groupings
mask = ids != -1
ids, val = ids[mask], val[mask]
if bins is None:
lab, lev = algorithms.factorize(val, sort=True)
llab = lambda lab, inc: lab[inc]
else:
# lab is a Categorical with categories an IntervalIndex
lab = cut(Series(val), bins, include_lowest=True)
lev = lab.cat.categories
lab = lev.take(lab.cat.codes)
llab = lambda lab, inc: lab[inc]._multiindex.codes[-1]
if is_interval_dtype(lab):
# TODO: should we do this inside II?
sorter = np.lexsort((lab.left, lab.right, ids))
else:
sorter = np.lexsort((lab, ids))
ids, lab = ids[sorter], lab[sorter]
# group boundaries are where group ids change
idx = np.r_[0, 1 + np.nonzero(ids[1:] != ids[:-1])[0]]
# new values are where sorted labels change
lchanges = llab(lab, slice(1, None)) != llab(lab, slice(None, -1))
inc = np.r_[True, lchanges]
inc[idx] = True # group boundaries are also new values
out = np.diff(np.nonzero(np.r_[inc, True])[0]) # value counts
# num. of times each group should be repeated
rep = partial(np.repeat, repeats=np.add.reduceat(inc, idx))
# multi-index components
labels = list(map(rep, self.grouper.recons_labels)) + [llab(lab, inc)]
levels = [ping.group_index for ping in self.grouper.groupings] + [lev]
names = self.grouper.names + [self._selection_name]
if dropna:
mask = labels[-1] != -1
if mask.all():
dropna = False
else:
out, labels = out[mask], [label[mask] for label in labels]
if normalize:
out = out.astype("float")
d = np.diff(np.r_[idx, len(ids)])
if dropna:
m = ids[lab == -1]
np.add.at(d, m, -1)
acc = rep(d)[mask]
else:
acc = rep(d)
out /= acc
if sort and bins is None:
cat = ids[inc][mask] if dropna else ids[inc]
sorter = np.lexsort((out if ascending else -out, cat))
out, labels[-1] = out[sorter], labels[-1][sorter]
if bins is None:
mi = MultiIndex(
levels=levels, codes=labels, names=names, verify_integrity=False
)
if is_integer_dtype(out):
out = ensure_int64(out)
return Series(out, index=mi, name=self._selection_name)
# for compat. with libgroupby.value_counts need to ensure every
# bin is present at every index level, null filled with zeros
diff = np.zeros(len(out), dtype="bool")
for lab in labels[:-1]:
diff |= np.r_[True, lab[1:] != lab[:-1]]
ncat, nbin = diff.sum(), len(levels[-1])
left = [np.repeat(np.arange(ncat), nbin), np.tile(np.arange(nbin), ncat)]
right = [diff.cumsum() - 1, labels[-1]]
_, idx = _get_join_indexers(left, right, sort=False, how="left")
out = np.where(idx != -1, out[idx], 0)
if sort:
sorter = np.lexsort((out if ascending else -out, left[0]))
out, left[-1] = out[sorter], left[-1][sorter]
# build the multi-index w/ full levels
codes = list(map(lambda lab: np.repeat(lab[diff], nbin), labels[:-1]))
codes.append(left[-1])
mi = MultiIndex(levels=levels, codes=codes, names=names, verify_integrity=False)
if is_integer_dtype(out):
out = ensure_int64(out)
return Series(out, index=mi, name=self._selection_name)
def count(self):
"""
Compute count of group, excluding missing values.
Returns
-------
Series
Count of values within each group.
"""
ids, _, ngroups = self.grouper.group_info
val = self.obj._internal_get_values()
mask = (ids != -1) & ~isna(val)
ids = ensure_platform_int(ids)
minlength = ngroups or 0
out = np.bincount(ids[mask], minlength=minlength)
return Series(
out,
index=self.grouper.result_index,
name=self._selection_name,
dtype="int64",
)
def _apply_to_column_groupbys(self, func):
""" return a pass thru """
return func(self)
def pct_change(self, periods=1, fill_method="pad", limit=None, freq=None):
"""Calculate pct_change of each value to previous entry in group"""
# TODO: Remove this conditional when #23918 is fixed
if freq:
return self.apply(
lambda x: x.pct_change(
periods=periods, fill_method=fill_method, limit=limit, freq=freq
)
)
filled = getattr(self, fill_method)(limit=limit)
fill_grp = filled.groupby(self.grouper.labels)
shifted = fill_grp.shift(periods=periods, freq=freq)
return (filled / shifted) - 1
@pin_whitelisted_properties(DataFrame, base.dataframe_apply_whitelist)
class DataFrameGroupBy(NDFrameGroupBy):
_apply_whitelist = base.dataframe_apply_whitelist
_block_agg_axis = 1
_agg_see_also_doc = dedent(
"""
See Also
--------
pandas.DataFrame.groupby.apply
pandas.DataFrame.groupby.transform
pandas.DataFrame.aggregate
"""
)
_agg_examples_doc = dedent(
"""
Examples
--------
>>> df = pd.DataFrame({'A': [1, 1, 2, 2],
... 'B': [1, 2, 3, 4],
... 'C': np.random.randn(4)})
>>> df
A B C
0 1 1 0.362838
1 1 2 0.227877
2 2 3 1.267767
3 2 4 -0.562860
The aggregation is for each column.
>>> df.groupby('A').agg('min')
B C
A
1 1 0.227877
2 3 -0.562860
Multiple aggregations
>>> df.groupby('A').agg(['min', 'max'])
B C
min max min max
A
1 1 2 0.227877 0.362838
2 3 4 -0.562860 1.267767
Select a column for aggregation
>>> df.groupby('A').B.agg(['min', 'max'])
min max
A
1 1 2
2 3 4
Different aggregations per column
>>> df.groupby('A').agg({'B': ['min', 'max'], 'C': 'sum'})
B C
min max sum
A
1 1 2 0.590716
2 3 4 0.704907
To control the output names with different aggregations per column,
pandas supports "named aggregation"
>>> df.groupby("A").agg(
... b_min=pd.NamedAgg(column="B", aggfunc="min"),
... c_sum=pd.NamedAgg(column="C", aggfunc="sum"))
b_min c_sum
A
1 1 -1.956929
2 3 -0.322183
- The keywords are the *output* column names
- The values are tuples whose first element is the column to select
and the second element is the aggregation to apply to that column.
Pandas provides the ``pandas.NamedAgg`` namedtuple with the fields
``['column', 'aggfunc']`` to make it clearer what the arguments are.
As usual, the aggregation can be a callable or a string alias.
See :ref:`groupby.aggregate.named` for more.
"""
)
@Substitution(
see_also=_agg_see_also_doc,
examples=_agg_examples_doc,
versionadded="",
klass="DataFrame",
axis="",
)
@Appender(_shared_docs["aggregate"])
def aggregate(self, func=None, *args, **kwargs):
return super().aggregate(func, *args, **kwargs)
agg = aggregate
def _gotitem(self, key, ndim, subset=None):
"""
sub-classes to define
return a sliced object
Parameters
----------
key : string / list of selections
ndim : 1,2
requested ndim of result
subset : object, default None
subset to act on
"""
if ndim == 2:
if subset is None:
subset = self.obj
return DataFrameGroupBy(
subset,
self.grouper,
selection=key,
grouper=self.grouper,
exclusions=self.exclusions,
as_index=self.as_index,
observed=self.observed,
)
elif ndim == 1:
if subset is None:
subset = self.obj[key]
return SeriesGroupBy(
subset, selection=key, grouper=self.grouper, observed=self.observed
)
raise AssertionError("invalid ndim for _gotitem")
def _wrap_generic_output(self, result, obj):
result_index = self.grouper.levels[0]
if self.axis == 0:
return DataFrame(result, index=obj.columns, columns=result_index).T
else:
return DataFrame(result, index=obj.index, columns=result_index)
def _get_data_to_aggregate(self):
obj = self._obj_with_exclusions
if self.axis == 1:
return obj.T._data, 1
else:
return obj._data, 1
def _insert_inaxis_grouper_inplace(self, result):
# zip in reverse so we can always insert at loc 0
izip = zip(
*map(
reversed,
(
self.grouper.names,
self.grouper.get_group_levels(),
[grp.in_axis for grp in self.grouper.groupings],
),
)
)
for name, lev, in_axis in izip:
if in_axis:
result.insert(0, name, lev)
def _wrap_aggregated_output(self, output, names=None):
agg_axis = 0 if self.axis == 1 else 1
agg_labels = self._obj_with_exclusions._get_axis(agg_axis)
output_keys = self._decide_output_index(output, agg_labels)
if not self.as_index:
result = DataFrame(output, columns=output_keys)
self._insert_inaxis_grouper_inplace(result)
result = result._consolidate()
else:
index = self.grouper.result_index
result = DataFrame(output, index=index, columns=output_keys)
if self.axis == 1:
result = result.T
return self._reindex_output(result)._convert(datetime=True)
def _wrap_transformed_output(self, output, names=None):
return DataFrame(output, index=self.obj.index)
def _wrap_agged_blocks(self, items, blocks):
if not self.as_index:
index = np.arange(blocks[0].values.shape[-1])
mgr = BlockManager(blocks, [items, index])
result = DataFrame(mgr)
self._insert_inaxis_grouper_inplace(result)
result = result._consolidate()
else:
index = self.grouper.result_index
mgr = BlockManager(blocks, [items, index])
result = DataFrame(mgr)
if self.axis == 1:
result = result.T
return self._reindex_output(result)._convert(datetime=True)
def _iterate_column_groupbys(self):
for i, colname in enumerate(self._selected_obj.columns):
yield colname, SeriesGroupBy(
self._selected_obj.iloc[:, i],
selection=colname,
grouper=self.grouper,
exclusions=self.exclusions,
)
def _apply_to_column_groupbys(self, func):
from pandas.core.reshape.concat import concat
return concat(
(func(col_groupby) for _, col_groupby in self._iterate_column_groupbys()),
keys=self._selected_obj.columns,
axis=1,
)
def count(self):
"""
Compute count of group, excluding missing values.
Returns
-------
DataFrame
Count of values within each group.
"""
data, _ = self._get_data_to_aggregate()
ids, _, ngroups = self.grouper.group_info
mask = ids != -1
val = (
(mask & ~_isna_ndarraylike(np.atleast_2d(blk.get_values())))
for blk in data.blocks
)
loc = (blk.mgr_locs for blk in data.blocks)
counter = partial(lib.count_level_2d, labels=ids, max_bin=ngroups, axis=1)
blk = map(make_block, map(counter, val), loc)
return self._wrap_agged_blocks(data.items, list(blk))
def nunique(self, dropna=True):
"""
Return DataFrame with number of distinct observations per group for
each column.
.. versionadded:: 0.20.0
Parameters
----------
dropna : boolean, default True
Don't include NaN in the counts.
Returns
-------
nunique: DataFrame
Examples
--------
>>> df = pd.DataFrame({'id': ['spam', 'egg', 'egg', 'spam',
... 'ham', 'ham'],
... 'value1': [1, 5, 5, 2, 5, 5],
... 'value2': list('abbaxy')})
>>> df
id value1 value2
0 spam 1 a
1 egg 5 b
2 egg 5 b
3 spam 2 a
4 ham 5 x
5 ham 5 y
>>> df.groupby('id').nunique()
id value1 value2
id
egg 1 1 1
ham 1 1 2
spam 1 2 1
Check for rows with the same id but conflicting values:
>>> df.groupby('id').filter(lambda g: (g.nunique() > 1).any())
id value1 value2
0 spam 1 a
3 spam 2 a
4 ham 5 x
5 ham 5 y
"""
obj = self._selected_obj
def groupby_series(obj, col=None):
return SeriesGroupBy(obj, selection=col, grouper=self.grouper).nunique(
dropna=dropna
)
if isinstance(obj, Series):
results = groupby_series(obj)
else:
from pandas.core.reshape.concat import concat
results = [groupby_series(obj[col], col) for col in obj.columns]
results = concat(results, axis=1)
results.columns.names = obj.columns.names
if not self.as_index:
results.index = ibase.default_index(len(results))
return results
boxplot = boxplot_frame_groupby
def _is_multi_agg_with_relabel(**kwargs):
"""
Check whether kwargs passed to .agg look like multi-agg with relabeling.
Parameters
----------
**kwargs : dict
Returns
-------
bool
Examples
--------
>>> _is_multi_agg_with_relabel(a='max')
False
>>> _is_multi_agg_with_relabel(a_max=('a', 'max'),
... a_min=('a', 'min'))
True
>>> _is_multi_agg_with_relabel()
False
"""
return all(isinstance(v, tuple) and len(v) == 2 for v in kwargs.values()) and kwargs
def _normalize_keyword_aggregation(kwargs):
"""
Normalize user-provided "named aggregation" kwargs.
Transforms from the new ``Dict[str, NamedAgg]`` style kwargs
to the old OrderedDict[str, List[scalar]]].
Parameters
----------
kwargs : dict
Returns
-------
aggspec : dict
The transformed kwargs.
columns : List[str]
The user-provided keys.
col_idx_order : List[int]
List of columns indices.
Examples
--------
>>> _normalize_keyword_aggregation({'output': ('input', 'sum')})
(OrderedDict([('input', ['sum'])]), ('output',), [('input', 'sum')])
"""
if not PY36:
kwargs = OrderedDict(sorted(kwargs.items()))
# Normalize the aggregation functions as Dict[column, List[func]],
# process normally, then fixup the names.
# TODO(Py35): When we drop python 3.5, change this to
# defaultdict(list)
# TODO: aggspec type: typing.OrderedDict[str, List[AggScalar]]
# May be hitting https://github.com/python/mypy/issues/5958
# saying it doesn't have an attribute __name__
aggspec = OrderedDict()
order = []
columns, pairs = list(zip(*kwargs.items()))
for name, (column, aggfunc) in zip(columns, pairs):
if column in aggspec:
aggspec[column].append(aggfunc)
else:
aggspec[column] = [aggfunc]
order.append((column, com.get_callable_name(aggfunc) or aggfunc))
# uniquify aggfunc name if duplicated in order list
uniquified_order = _make_unique(order)
# GH 25719, due to aggspec will change the order of assigned columns in aggregation
# uniquified_aggspec will store uniquified order list and will compare it with order
# based on index
aggspec_order = [
(column, com.get_callable_name(aggfunc) or aggfunc)
for column, aggfuncs in aggspec.items()
for aggfunc in aggfuncs
]
uniquified_aggspec = _make_unique(aggspec_order)
# get the new indice of columns by comparison
col_idx_order = Index(uniquified_aggspec).get_indexer(uniquified_order)
return aggspec, columns, col_idx_order
def _make_unique(seq):
"""Uniquify aggfunc name of the pairs in the order list
Examples:
--------
>>> _make_unique([('a', '<lambda>'), ('a', '<lambda>'), ('b', '<lambda>')])
[('a', '<lambda>_0'), ('a', '<lambda>_1'), ('b', '<lambda>')]
"""
return [
(pair[0], "_".join([pair[1], str(seq[:i].count(pair))]))
if seq.count(pair) > 1
else pair
for i, pair in enumerate(seq)
]
# TODO: Can't use, because mypy doesn't like us setting __name__
# error: "partial[Any]" has no attribute "__name__"
# the type is:
# typing.Sequence[Callable[..., ScalarResult]]
# -> typing.Sequence[Callable[..., ScalarResult]]:
def _managle_lambda_list(aggfuncs: Sequence[Any]) -> Sequence[Any]:
"""
Possibly mangle a list of aggfuncs.
Parameters
----------
aggfuncs : Sequence
Returns
-------
mangled: list-like
A new AggSpec sequence, where lambdas have been converted
to have unique names.
Notes
-----
If just one aggfunc is passed, the name will not be mangled.
"""
if len(aggfuncs) <= 1:
# don't mangle for .agg([lambda x: .])
return aggfuncs
i = 0
mangled_aggfuncs = []
for aggfunc in aggfuncs:
if com.get_callable_name(aggfunc) == "<lambda>":
aggfunc = functools.partial(aggfunc)
aggfunc.__name__ = "<lambda_{}>".format(i)
i += 1
mangled_aggfuncs.append(aggfunc)
return mangled_aggfuncs
def _maybe_mangle_lambdas(agg_spec: Any) -> Any:
"""
Make new lambdas with unique names.
Parameters
----------
agg_spec : Any
An argument to NDFrameGroupBy.agg.
Non-dict-like `agg_spec` are pass through as is.
For dict-like `agg_spec` a new spec is returned
with name-mangled lambdas.
Returns
-------
mangled : Any
Same type as the input.
Examples
--------
>>> _maybe_mangle_lambdas('sum')
'sum'
>>> _maybe_mangle_lambdas([lambda: 1, lambda: 2]) # doctest: +SKIP
[<function __main__.<lambda_0>,
<function pandas...._make_lambda.<locals>.f(*args, **kwargs)>]
"""
is_dict = is_dict_like(agg_spec)
if not (is_dict or is_list_like(agg_spec)):
return agg_spec
mangled_aggspec = type(agg_spec)() # dict or OrderdDict
if is_dict:
for key, aggfuncs in agg_spec.items():
if is_list_like(aggfuncs) and not is_dict_like(aggfuncs):
mangled_aggfuncs = _managle_lambda_list(aggfuncs)
else:
mangled_aggfuncs = aggfuncs
mangled_aggspec[key] = mangled_aggfuncs
else:
mangled_aggspec = _managle_lambda_list(agg_spec)
return mangled_aggspec
def _recast_datetimelike_result(result: DataFrame) -> DataFrame:
"""
If we have date/time like in the original, then coerce dates
as we are stacking can easily have object dtypes here.
Parameters
----------
result : DataFrame
Returns
-------
DataFrame
Notes
-----
- Assumes Groupby._selected_obj has ndim==2 and at least one
datetimelike column
"""
result = result.copy()
obj_cols = [
idx
for idx in range(len(result.columns))
if is_object_dtype(result.dtypes.iloc[idx])
]
# See GH#26285
for n in obj_cols:
converted = maybe_convert_objects(
result.iloc[:, n].values, convert_numeric=False
)
result.iloc[:, n] = converted
return result
| BugsInPy/BugsInPy/temp/projects/pandas/bug-140-fixed/pandas/pandas/core/groupby/generic.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-140-buggy/pandas/pandas/core/groupby/generic.py |
pandas-bug-26 | import operator
from shutil import get_terminal_size
from typing import Dict, Hashable, List, Type, Union, cast
from warnings import warn
import numpy as np
from pandas._config import get_option
from pandas._libs import algos as libalgos, hashtable as htable
from pandas._typing import ArrayLike, Dtype, Ordered, Scalar
from pandas.compat.numpy import function as nv
from pandas.util._decorators import (
Appender,
Substitution,
cache_readonly,
deprecate_kwarg,
doc,
)
from pandas.util._validators import validate_bool_kwarg, validate_fillna_kwargs
from pandas.core.dtypes.cast import (
coerce_indexer_dtype,
maybe_cast_to_extension_array,
maybe_infer_to_datetimelike,
)
from pandas.core.dtypes.common import (
ensure_int64,
ensure_object,
ensure_platform_int,
is_categorical_dtype,
is_datetime64_dtype,
is_dict_like,
is_dtype_equal,
is_extension_array_dtype,
is_integer_dtype,
is_iterator,
is_list_like,
is_object_dtype,
is_scalar,
is_sequence,
is_timedelta64_dtype,
needs_i8_conversion,
)
from pandas.core.dtypes.dtypes import CategoricalDtype
from pandas.core.dtypes.generic import ABCIndexClass, ABCSeries
from pandas.core.dtypes.inference import is_hashable
from pandas.core.dtypes.missing import isna, notna
from pandas.core import ops
from pandas.core.accessor import PandasDelegate, delegate_names
import pandas.core.algorithms as algorithms
from pandas.core.algorithms import _get_data_algo, factorize, take, take_1d, unique1d
from pandas.core.arrays.base import ExtensionArray, _extension_array_shared_docs
from pandas.core.base import NoNewAttributesMixin, PandasObject, _shared_docs
import pandas.core.common as com
from pandas.core.construction import array, extract_array, sanitize_array
from pandas.core.indexers import check_array_indexer, deprecate_ndim_indexing
from pandas.core.missing import interpolate_2d
from pandas.core.ops.common import unpack_zerodim_and_defer
from pandas.core.sorting import nargsort
from pandas.io.formats import console
def _cat_compare_op(op):
opname = f"__{op.__name__}__"
@unpack_zerodim_and_defer(opname)
def func(self, other):
if is_list_like(other) and len(other) != len(self):
# TODO: Could this fail if the categories are listlike objects?
raise ValueError("Lengths must match.")
if not self.ordered:
if opname in ["__lt__", "__gt__", "__le__", "__ge__"]:
raise TypeError(
"Unordered Categoricals can only compare equality or not"
)
if isinstance(other, Categorical):
# Two Categoricals can only be be compared if the categories are
# the same (maybe up to ordering, depending on ordered)
msg = "Categoricals can only be compared if 'categories' are the same."
if len(self.categories) != len(other.categories):
raise TypeError(msg + " Categories are different lengths")
elif self.ordered and not (self.categories == other.categories).all():
raise TypeError(msg)
elif not set(self.categories) == set(other.categories):
raise TypeError(msg)
if not (self.ordered == other.ordered):
raise TypeError(
"Categoricals can only be compared if 'ordered' is the same"
)
if not self.ordered and not self.categories.equals(other.categories):
# both unordered and different order
other_codes = _get_codes_for_values(other, self.categories)
else:
other_codes = other._codes
f = getattr(self._codes, opname)
ret = f(other_codes)
mask = (self._codes == -1) | (other_codes == -1)
if mask.any():
# In other series, the leads to False, so do that here too
if opname == "__ne__":
ret[(self._codes == -1) & (other_codes == -1)] = True
else:
ret[mask] = False
return ret
if is_scalar(other):
if other in self.categories:
i = self.categories.get_loc(other)
ret = getattr(self._codes, opname)(i)
if opname not in {"__eq__", "__ge__", "__gt__"}:
# check for NaN needed if we are not equal or larger
mask = self._codes == -1
ret[mask] = False
return ret
else:
if opname == "__eq__":
return np.zeros(len(self), dtype=bool)
elif opname == "__ne__":
return np.ones(len(self), dtype=bool)
else:
raise TypeError(
f"Cannot compare a Categorical for op {opname} with a "
"scalar, which is not a category."
)
else:
# allow categorical vs object dtype array comparisons for equality
# these are only positional comparisons
if opname in ["__eq__", "__ne__"]:
return getattr(np.array(self), opname)(np.array(other))
raise TypeError(
f"Cannot compare a Categorical for op {opname} with "
f"type {type(other)}.\nIf you want to compare values, "
"use 'np.asarray(cat) <op> other'."
)
func.__name__ = opname
return func
def contains(cat, key, container):
"""
Helper for membership check for ``key`` in ``cat``.
This is a helper method for :method:`__contains__`
and :class:`CategoricalIndex.__contains__`.
Returns True if ``key`` is in ``cat.categories`` and the
location of ``key`` in ``categories`` is in ``container``.
Parameters
----------
cat : :class:`Categorical`or :class:`categoricalIndex`
key : a hashable object
The key to check membership for.
container : Container (e.g. list-like or mapping)
The container to check for membership in.
Returns
-------
is_in : bool
True if ``key`` is in ``self.categories`` and location of
``key`` in ``categories`` is in ``container``, else False.
Notes
-----
This method does not check for NaN values. Do that separately
before calling this method.
"""
hash(key)
# get location of key in categories.
# If a KeyError, the key isn't in categories, so logically
# can't be in container either.
try:
loc = cat.categories.get_loc(key)
except (KeyError, TypeError):
return False
# loc is the location of key in categories, but also the *value*
# for key in container. So, `key` may be in categories,
# but still not in `container`. Example ('b' in categories,
# but not in values):
# 'b' in Categorical(['a'], categories=['a', 'b']) # False
if is_scalar(loc):
return loc in container
else:
# if categories is an IntervalIndex, loc is an array.
return any(loc_ in container for loc_ in loc)
_codes_doc = """
The category codes of this categorical.
Level codes are an array if integer which are the positions of the real
values in the categories array.
There is not setter, use the other categorical methods and the normal item
setter to change values in the categorical.
"""
class Categorical(ExtensionArray, PandasObject):
"""
Represent a categorical variable in classic R / S-plus fashion.
`Categoricals` can only take on only a limited, and usually fixed, number
of possible values (`categories`). In contrast to statistical categorical
variables, a `Categorical` might have an order, but numerical operations
(additions, divisions, ...) are not possible.
All values of the `Categorical` are either in `categories` or `np.nan`.
Assigning values outside of `categories` will raise a `ValueError`. Order
is defined by the order of the `categories`, not lexical order of the
values.
Parameters
----------
values : list-like
The values of the categorical. If categories are given, values not in
categories will be replaced with NaN.
categories : Index-like (unique), optional
The unique categories for this categorical. If not given, the
categories are assumed to be the unique values of `values` (sorted, if
possible, otherwise in the order in which they appear).
ordered : bool, default False
Whether or not this categorical is treated as a ordered categorical.
If True, the resulting categorical will be ordered.
An ordered categorical respects, when sorted, the order of its
`categories` attribute (which in turn is the `categories` argument, if
provided).
dtype : CategoricalDtype
An instance of ``CategoricalDtype`` to use for this categorical.
Attributes
----------
categories : Index
The categories of this categorical
codes : ndarray
The codes (integer positions, which point to the categories) of this
categorical, read only.
ordered : bool
Whether or not this Categorical is ordered.
dtype : CategoricalDtype
The instance of ``CategoricalDtype`` storing the ``categories``
and ``ordered``.
Methods
-------
from_codes
__array__
Raises
------
ValueError
If the categories do not validate.
TypeError
If an explicit ``ordered=True`` is given but no `categories` and the
`values` are not sortable.
See Also
--------
CategoricalDtype : Type for categorical data.
CategoricalIndex : An Index with an underlying ``Categorical``.
Notes
-----
See the `user guide
<https://pandas.pydata.org/pandas-docs/stable/user_guide/categorical.html>`_
for more.
Examples
--------
>>> pd.Categorical([1, 2, 3, 1, 2, 3])
[1, 2, 3, 1, 2, 3]
Categories (3, int64): [1, 2, 3]
>>> pd.Categorical(['a', 'b', 'c', 'a', 'b', 'c'])
[a, b, c, a, b, c]
Categories (3, object): [a, b, c]
Ordered `Categoricals` can be sorted according to the custom order
of the categories and can have a min and max value.
>>> c = pd.Categorical(['a', 'b', 'c', 'a', 'b', 'c'], ordered=True,
... categories=['c', 'b', 'a'])
>>> c
[a, b, c, a, b, c]
Categories (3, object): [c < b < a]
>>> c.min()
'c'
"""
# For comparisons, so that numpy uses our implementation if the compare
# ops, which raise
__array_priority__ = 1000
_dtype = CategoricalDtype(ordered=False)
# tolist is not actually deprecated, just suppressed in the __dir__
_deprecations = PandasObject._deprecations | frozenset(["tolist"])
_typ = "categorical"
def __init__(
self, values, categories=None, ordered=None, dtype=None, fastpath=False
):
dtype = CategoricalDtype._from_values_or_dtype(
values, categories, ordered, dtype
)
# At this point, dtype is always a CategoricalDtype, but
# we may have dtype.categories be None, and we need to
# infer categories in a factorization step further below
if fastpath:
self._codes = coerce_indexer_dtype(values, dtype.categories)
self._dtype = self._dtype.update_dtype(dtype)
return
# null_mask indicates missing values we want to exclude from inference.
# This means: only missing values in list-likes (not arrays/ndframes).
null_mask = np.array(False)
# sanitize input
if is_categorical_dtype(values):
if dtype.categories is None:
dtype = CategoricalDtype(values.categories, dtype.ordered)
elif not isinstance(values, (ABCIndexClass, ABCSeries)):
# sanitize_array coerces np.nan to a string under certain versions
# of numpy
values = maybe_infer_to_datetimelike(values, convert_dates=True)
if not isinstance(values, np.ndarray):
values = _convert_to_list_like(values)
# By convention, empty lists result in object dtype:
sanitize_dtype = "object" if len(values) == 0 else None
null_mask = isna(values)
if null_mask.any():
values = [values[idx] for idx in np.where(~null_mask)[0]]
values = sanitize_array(values, None, dtype=sanitize_dtype)
if dtype.categories is None:
try:
codes, categories = factorize(values, sort=True)
except TypeError as err:
codes, categories = factorize(values, sort=False)
if dtype.ordered:
# raise, as we don't have a sortable data structure and so
# the user should give us one by specifying categories
raise TypeError(
"'values' is not ordered, please "
"explicitly specify the categories order "
"by passing in a categories argument."
) from err
except ValueError as err:
# FIXME
raise NotImplementedError(
"> 1 ndim Categorical are not supported at this time"
) from err
# we're inferring from values
dtype = CategoricalDtype(categories, dtype.ordered)
elif is_categorical_dtype(values):
old_codes = (
values._values.codes if isinstance(values, ABCSeries) else values.codes
)
codes = recode_for_categories(
old_codes, values.dtype.categories, dtype.categories
)
else:
codes = _get_codes_for_values(values, dtype.categories)
if null_mask.any():
# Reinsert -1 placeholders for previously removed missing values
full_codes = -np.ones(null_mask.shape, dtype=codes.dtype)
full_codes[~null_mask] = codes
codes = full_codes
self._dtype = self._dtype.update_dtype(dtype)
self._codes = coerce_indexer_dtype(codes, dtype.categories)
@property
def categories(self):
"""
The categories of this categorical.
Setting assigns new values to each category (effectively a rename of
each individual category).
The assigned value has to be a list-like object. All items must be
unique and the number of items in the new categories must be the same
as the number of items in the old categories.
Assigning to `categories` is a inplace operation!
Raises
------
ValueError
If the new categories do not validate as categories or if the
number of new categories is unequal the number of old categories
See Also
--------
rename_categories : Rename categories.
reorder_categories : Reorder categories.
add_categories : Add new categories.
remove_categories : Remove the specified categories.
remove_unused_categories : Remove categories which are not used.
set_categories : Set the categories to the specified ones.
"""
return self.dtype.categories
@categories.setter
def categories(self, categories):
new_dtype = CategoricalDtype(categories, ordered=self.ordered)
if self.dtype.categories is not None and len(self.dtype.categories) != len(
new_dtype.categories
):
raise ValueError(
"new categories need to have the same number of "
"items as the old categories!"
)
self._dtype = new_dtype
@property
def ordered(self) -> Ordered:
"""
Whether the categories have an ordered relationship.
"""
return self.dtype.ordered
@property
def dtype(self) -> CategoricalDtype:
"""
The :class:`~pandas.api.types.CategoricalDtype` for this instance.
"""
return self._dtype
@property
def _constructor(self) -> Type["Categorical"]:
return Categorical
@classmethod
def _from_sequence(cls, scalars, dtype=None, copy=False):
return Categorical(scalars, dtype=dtype)
def _formatter(self, boxed=False):
# Defer to CategoricalFormatter's formatter.
return None
def copy(self) -> "Categorical":
"""
Copy constructor.
"""
return self._constructor(
values=self._codes.copy(), dtype=self.dtype, fastpath=True
)
def astype(self, dtype: Dtype, copy: bool = True) -> ArrayLike:
"""
Coerce this type to another dtype
Parameters
----------
dtype : numpy dtype or pandas type
copy : bool, default True
By default, astype always returns a newly allocated object.
If copy is set to False and dtype is categorical, the original
object is returned.
"""
if is_categorical_dtype(dtype):
dtype = cast(Union[str, CategoricalDtype], dtype)
# GH 10696/18593
dtype = self.dtype.update_dtype(dtype)
self = self.copy() if copy else self
if dtype == self.dtype:
return self
return self._set_dtype(dtype)
if is_extension_array_dtype(dtype):
return array(self, dtype=dtype, copy=copy) # type: ignore # GH 28770
if is_integer_dtype(dtype) and self.isna().any():
raise ValueError("Cannot convert float NaN to integer")
return np.array(self, dtype=dtype, copy=copy)
@cache_readonly
def size(self) -> int:
"""
Return the len of myself.
"""
return self._codes.size
@cache_readonly
def itemsize(self) -> int:
"""
return the size of a single category
"""
return self.categories.itemsize
def tolist(self) -> List[Scalar]:
"""
Return a list of the values.
These are each a scalar type, which is a Python scalar
(for str, int, float) or a pandas scalar
(for Timestamp/Timedelta/Interval/Period)
"""
return list(self)
to_list = tolist
@classmethod
def _from_inferred_categories(
cls, inferred_categories, inferred_codes, dtype, true_values=None
):
"""
Construct a Categorical from inferred values.
For inferred categories (`dtype` is None) the categories are sorted.
For explicit `dtype`, the `inferred_categories` are cast to the
appropriate type.
Parameters
----------
inferred_categories : Index
inferred_codes : Index
dtype : CategoricalDtype or 'category'
true_values : list, optional
If none are provided, the default ones are
"True", "TRUE", and "true."
Returns
-------
Categorical
"""
from pandas import Index, to_numeric, to_datetime, to_timedelta
cats = Index(inferred_categories)
known_categories = (
isinstance(dtype, CategoricalDtype) and dtype.categories is not None
)
if known_categories:
# Convert to a specialized type with `dtype` if specified.
if dtype.categories.is_numeric():
cats = to_numeric(inferred_categories, errors="coerce")
elif is_datetime64_dtype(dtype.categories):
cats = to_datetime(inferred_categories, errors="coerce")
elif is_timedelta64_dtype(dtype.categories):
cats = to_timedelta(inferred_categories, errors="coerce")
elif dtype.categories.is_boolean():
if true_values is None:
true_values = ["True", "TRUE", "true"]
cats = cats.isin(true_values)
if known_categories:
# Recode from observation order to dtype.categories order.
categories = dtype.categories
codes = recode_for_categories(inferred_codes, cats, categories)
elif not cats.is_monotonic_increasing:
# Sort categories and recode for unknown categories.
unsorted = cats.copy()
categories = cats.sort_values()
codes = recode_for_categories(inferred_codes, unsorted, categories)
dtype = CategoricalDtype(categories, ordered=False)
else:
dtype = CategoricalDtype(cats, ordered=False)
codes = inferred_codes
return cls(codes, dtype=dtype, fastpath=True)
@classmethod
def from_codes(cls, codes, categories=None, ordered=None, dtype=None):
"""
Make a Categorical type from codes and categories or dtype.
This constructor is useful if you already have codes and
categories/dtype and so do not need the (computation intensive)
factorization step, which is usually done on the constructor.
If your data does not follow this convention, please use the normal
constructor.
Parameters
----------
codes : array-like of int
An integer array, where each integer points to a category in
categories or dtype.categories, or else is -1 for NaN.
categories : index-like, optional
The categories for the categorical. Items need to be unique.
If the categories are not given here, then they must be provided
in `dtype`.
ordered : bool, optional
Whether or not this categorical is treated as an ordered
categorical. If not given here or in `dtype`, the resulting
categorical will be unordered.
dtype : CategoricalDtype or "category", optional
If :class:`CategoricalDtype`, cannot be used together with
`categories` or `ordered`.
.. versionadded:: 0.24.0
When `dtype` is provided, neither `categories` nor `ordered`
should be provided.
Returns
-------
Categorical
Examples
--------
>>> dtype = pd.CategoricalDtype(['a', 'b'], ordered=True)
>>> pd.Categorical.from_codes(codes=[0, 1, 0, 1], dtype=dtype)
[a, b, a, b]
Categories (2, object): [a < b]
"""
dtype = CategoricalDtype._from_values_or_dtype(
categories=categories, ordered=ordered, dtype=dtype
)
if dtype.categories is None:
msg = (
"The categories must be provided in 'categories' or "
"'dtype'. Both were None."
)
raise ValueError(msg)
if is_extension_array_dtype(codes) and is_integer_dtype(codes):
# Avoid the implicit conversion of Int to object
if isna(codes).any():
raise ValueError("codes cannot contain NA values")
codes = codes.to_numpy(dtype=np.int64)
else:
codes = np.asarray(codes)
if len(codes) and not is_integer_dtype(codes):
raise ValueError("codes need to be array-like integers")
if len(codes) and (codes.max() >= len(dtype.categories) or codes.min() < -1):
raise ValueError("codes need to be between -1 and len(categories)-1")
return cls(codes, dtype=dtype, fastpath=True)
def _get_codes(self):
"""
Get the codes.
Returns
-------
codes : integer array view
A non writable view of the `codes` array.
"""
v = self._codes.view()
v.flags.writeable = False
return v
def _set_codes(self, codes):
"""
Not settable by the user directly
"""
raise ValueError("cannot set Categorical codes directly")
codes = property(fget=_get_codes, fset=_set_codes, doc=_codes_doc)
def _set_categories(self, categories, fastpath=False):
"""
Sets new categories inplace
Parameters
----------
fastpath : bool, default False
Don't perform validation of the categories for uniqueness or nulls
Examples
--------
>>> c = pd.Categorical(['a', 'b'])
>>> c
[a, b]
Categories (2, object): [a, b]
>>> c._set_categories(pd.Index(['a', 'c']))
>>> c
[a, c]
Categories (2, object): [a, c]
"""
if fastpath:
new_dtype = CategoricalDtype._from_fastpath(categories, self.ordered)
else:
new_dtype = CategoricalDtype(categories, ordered=self.ordered)
if (
not fastpath
and self.dtype.categories is not None
and len(new_dtype.categories) != len(self.dtype.categories)
):
raise ValueError(
"new categories need to have the same number of "
"items than the old categories!"
)
self._dtype = new_dtype
def _set_dtype(self, dtype: CategoricalDtype) -> "Categorical":
"""
Internal method for directly updating the CategoricalDtype
Parameters
----------
dtype : CategoricalDtype
Notes
-----
We don't do any validation here. It's assumed that the dtype is
a (valid) instance of `CategoricalDtype`.
"""
codes = recode_for_categories(self.codes, self.categories, dtype.categories)
return type(self)(codes, dtype=dtype, fastpath=True)
def set_ordered(self, value, inplace=False):
"""
Set the ordered attribute to the boolean value.
Parameters
----------
value : bool
Set whether this categorical is ordered (True) or not (False).
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to the value.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
new_dtype = CategoricalDtype(self.categories, ordered=value)
cat = self if inplace else self.copy()
cat._dtype = new_dtype
if not inplace:
return cat
def as_ordered(self, inplace=False):
"""
Set the Categorical to be ordered.
Parameters
----------
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to True.
Returns
-------
Categorical
Ordered Categorical.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
return self.set_ordered(True, inplace=inplace)
def as_unordered(self, inplace=False):
"""
Set the Categorical to be unordered.
Parameters
----------
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to False.
Returns
-------
Categorical
Unordered Categorical.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
return self.set_ordered(False, inplace=inplace)
def set_categories(self, new_categories, ordered=None, rename=False, inplace=False):
"""
Set the categories to the specified new_categories.
`new_categories` can include new categories (which will result in
unused categories) or remove old categories (which results in values
set to NaN). If `rename==True`, the categories will simple be renamed
(less or more items than in old categories will result in values set to
NaN or in unused categories respectively).
This method can be used to perform more than one action of adding,
removing, and reordering simultaneously and is therefore faster than
performing the individual steps via the more specialised methods.
On the other hand this methods does not do checks (e.g., whether the
old categories are included in the new categories on a reorder), which
can result in surprising changes, for example when using special string
dtypes, which does not considers a S1 string equal to a single char
python string.
Parameters
----------
new_categories : Index-like
The categories in new order.
ordered : bool, default False
Whether or not the categorical is treated as a ordered categorical.
If not given, do not change the ordered information.
rename : bool, default False
Whether or not the new_categories should be considered as a rename
of the old categories or as reordered categories.
inplace : bool, default False
Whether or not to reorder the categories in-place or return a copy
of this categorical with reordered categories.
Returns
-------
Categorical with reordered categories or None if inplace.
Raises
------
ValueError
If new_categories does not validate as categories
See Also
--------
rename_categories : Rename categories.
reorder_categories : Reorder categories.
add_categories : Add new categories.
remove_categories : Remove the specified categories.
remove_unused_categories : Remove categories which are not used.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if ordered is None:
ordered = self.dtype.ordered
new_dtype = CategoricalDtype(new_categories, ordered=ordered)
cat = self if inplace else self.copy()
if rename:
if cat.dtype.categories is not None and len(new_dtype.categories) < len(
cat.dtype.categories
):
# remove all _codes which are larger and set to -1/NaN
cat._codes[cat._codes >= len(new_dtype.categories)] = -1
else:
codes = recode_for_categories(
cat.codes, cat.categories, new_dtype.categories
)
cat._codes = codes
cat._dtype = new_dtype
if not inplace:
return cat
def rename_categories(self, new_categories, inplace=False):
"""
Rename categories.
Parameters
----------
new_categories : list-like, dict-like or callable
New categories which will replace old categories.
* list-like: all items must be unique and the number of items in
the new categories must match the existing number of categories.
* dict-like: specifies a mapping from
old categories to new. Categories not contained in the mapping
are passed through and extra categories in the mapping are
ignored.
* callable : a callable that is called on all items in the old
categories and whose return values comprise the new categories.
.. versionadded:: 0.23.0.
inplace : bool, default False
Whether or not to rename the categories inplace or return a copy of
this categorical with renamed categories.
Returns
-------
cat : Categorical or None
With ``inplace=False``, the new categorical is returned.
With ``inplace=True``, there is no return value.
Raises
------
ValueError
If new categories are list-like and do not have the same number of
items than the current categories or do not validate as categories
See Also
--------
reorder_categories : Reorder categories.
add_categories : Add new categories.
remove_categories : Remove the specified categories.
remove_unused_categories : Remove categories which are not used.
set_categories : Set the categories to the specified ones.
Examples
--------
>>> c = pd.Categorical(['a', 'a', 'b'])
>>> c.rename_categories([0, 1])
[0, 0, 1]
Categories (2, int64): [0, 1]
For dict-like ``new_categories``, extra keys are ignored and
categories not in the dictionary are passed through
>>> c.rename_categories({'a': 'A', 'c': 'C'})
[A, A, b]
Categories (2, object): [A, b]
You may also provide a callable to create the new categories
>>> c.rename_categories(lambda x: x.upper())
[A, A, B]
Categories (2, object): [A, B]
"""
inplace = validate_bool_kwarg(inplace, "inplace")
cat = self if inplace else self.copy()
if is_dict_like(new_categories):
cat.categories = [new_categories.get(item, item) for item in cat.categories]
elif callable(new_categories):
cat.categories = [new_categories(item) for item in cat.categories]
else:
cat.categories = new_categories
if not inplace:
return cat
def reorder_categories(self, new_categories, ordered=None, inplace=False):
"""
Reorder categories as specified in new_categories.
`new_categories` need to include all old categories and no new category
items.
Parameters
----------
new_categories : Index-like
The categories in new order.
ordered : bool, optional
Whether or not the categorical is treated as a ordered categorical.
If not given, do not change the ordered information.
inplace : bool, default False
Whether or not to reorder the categories inplace or return a copy of
this categorical with reordered categories.
Returns
-------
cat : Categorical with reordered categories or None if inplace.
Raises
------
ValueError
If the new categories do not contain all old category items or any
new ones
See Also
--------
rename_categories : Rename categories.
add_categories : Add new categories.
remove_categories : Remove the specified categories.
remove_unused_categories : Remove categories which are not used.
set_categories : Set the categories to the specified ones.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if set(self.dtype.categories) != set(new_categories):
raise ValueError(
"items in new_categories are not the same as in old categories"
)
return self.set_categories(new_categories, ordered=ordered, inplace=inplace)
def add_categories(self, new_categories, inplace=False):
"""
Add new categories.
`new_categories` will be included at the last/highest place in the
categories and will be unused directly after this call.
Parameters
----------
new_categories : category or list-like of category
The new categories to be included.
inplace : bool, default False
Whether or not to add the categories inplace or return a copy of
this categorical with added categories.
Returns
-------
cat : Categorical with new categories added or None if inplace.
Raises
------
ValueError
If the new categories include old categories or do not validate as
categories
See Also
--------
rename_categories : Rename categories.
reorder_categories : Reorder categories.
remove_categories : Remove the specified categories.
remove_unused_categories : Remove categories which are not used.
set_categories : Set the categories to the specified ones.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not is_list_like(new_categories):
new_categories = [new_categories]
already_included = set(new_categories) & set(self.dtype.categories)
if len(already_included) != 0:
raise ValueError(
f"new categories must not include old categories: {already_included}"
)
new_categories = list(self.dtype.categories) + list(new_categories)
new_dtype = CategoricalDtype(new_categories, self.ordered)
cat = self if inplace else self.copy()
cat._dtype = new_dtype
cat._codes = coerce_indexer_dtype(cat._codes, new_dtype.categories)
if not inplace:
return cat
def remove_categories(self, removals, inplace=False):
"""
Remove the specified categories.
`removals` must be included in the old categories. Values which were in
the removed categories will be set to NaN
Parameters
----------
removals : category or list of categories
The categories which should be removed.
inplace : bool, default False
Whether or not to remove the categories inplace or return a copy of
this categorical with removed categories.
Returns
-------
cat : Categorical with removed categories or None if inplace.
Raises
------
ValueError
If the removals are not contained in the categories
See Also
--------
rename_categories : Rename categories.
reorder_categories : Reorder categories.
add_categories : Add new categories.
remove_unused_categories : Remove categories which are not used.
set_categories : Set the categories to the specified ones.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not is_list_like(removals):
removals = [removals]
removal_set = set(removals)
not_included = removal_set - set(self.dtype.categories)
new_categories = [c for c in self.dtype.categories if c not in removal_set]
# GH 10156
if any(isna(removals)):
not_included = {x for x in not_included if notna(x)}
new_categories = [x for x in new_categories if notna(x)]
if len(not_included) != 0:
raise ValueError(f"removals must all be in old categories: {not_included}")
return self.set_categories(
new_categories, ordered=self.ordered, rename=False, inplace=inplace
)
def remove_unused_categories(self, inplace=False):
"""
Remove categories which are not used.
Parameters
----------
inplace : bool, default False
Whether or not to drop unused categories inplace or return a copy of
this categorical with unused categories dropped.
Returns
-------
cat : Categorical with unused categories dropped or None if inplace.
See Also
--------
rename_categories : Rename categories.
reorder_categories : Reorder categories.
add_categories : Add new categories.
remove_categories : Remove the specified categories.
set_categories : Set the categories to the specified ones.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
cat = self if inplace else self.copy()
idx, inv = np.unique(cat._codes, return_inverse=True)
if idx.size != 0 and idx[0] == -1: # na sentinel
idx, inv = idx[1:], inv - 1
new_categories = cat.dtype.categories.take(idx)
new_dtype = CategoricalDtype._from_fastpath(
new_categories, ordered=self.ordered
)
cat._dtype = new_dtype
cat._codes = coerce_indexer_dtype(inv, new_dtype.categories)
if not inplace:
return cat
def map(self, mapper):
"""
Map categories using input correspondence (dict, Series, or function).
Maps the categories to new categories. If the mapping correspondence is
one-to-one the result is a :class:`~pandas.Categorical` which has the
same order property as the original, otherwise a :class:`~pandas.Index`
is returned. NaN values are unaffected.
If a `dict` or :class:`~pandas.Series` is used any unmapped category is
mapped to `NaN`. Note that if this happens an :class:`~pandas.Index`
will be returned.
Parameters
----------
mapper : function, dict, or Series
Mapping correspondence.
Returns
-------
pandas.Categorical or pandas.Index
Mapped categorical.
See Also
--------
CategoricalIndex.map : Apply a mapping correspondence on a
:class:`~pandas.CategoricalIndex`.
Index.map : Apply a mapping correspondence on an
:class:`~pandas.Index`.
Series.map : Apply a mapping correspondence on a
:class:`~pandas.Series`.
Series.apply : Apply more complex functions on a
:class:`~pandas.Series`.
Examples
--------
>>> cat = pd.Categorical(['a', 'b', 'c'])
>>> cat
[a, b, c]
Categories (3, object): [a, b, c]
>>> cat.map(lambda x: x.upper())
[A, B, C]
Categories (3, object): [A, B, C]
>>> cat.map({'a': 'first', 'b': 'second', 'c': 'third'})
[first, second, third]
Categories (3, object): [first, second, third]
If the mapping is one-to-one the ordering of the categories is
preserved:
>>> cat = pd.Categorical(['a', 'b', 'c'], ordered=True)
>>> cat
[a, b, c]
Categories (3, object): [a < b < c]
>>> cat.map({'a': 3, 'b': 2, 'c': 1})
[3, 2, 1]
Categories (3, int64): [3 < 2 < 1]
If the mapping is not one-to-one an :class:`~pandas.Index` is returned:
>>> cat.map({'a': 'first', 'b': 'second', 'c': 'first'})
Index(['first', 'second', 'first'], dtype='object')
If a `dict` is used, all unmapped categories are mapped to `NaN` and
the result is an :class:`~pandas.Index`:
>>> cat.map({'a': 'first', 'b': 'second'})
Index(['first', 'second', nan], dtype='object')
"""
new_categories = self.categories.map(mapper)
try:
return self.from_codes(
self._codes.copy(), categories=new_categories, ordered=self.ordered
)
except ValueError:
# NA values are represented in self._codes with -1
# np.take causes NA values to take final element in new_categories
if np.any(self._codes == -1):
new_categories = new_categories.insert(len(new_categories), np.nan)
return np.take(new_categories, self._codes)
__eq__ = _cat_compare_op(operator.eq)
__ne__ = _cat_compare_op(operator.ne)
__lt__ = _cat_compare_op(operator.lt)
__gt__ = _cat_compare_op(operator.gt)
__le__ = _cat_compare_op(operator.le)
__ge__ = _cat_compare_op(operator.ge)
# for Series/ndarray like compat
@property
def shape(self):
"""
Shape of the Categorical.
For internal compatibility with numpy arrays.
Returns
-------
shape : tuple
"""
return tuple([len(self._codes)])
def shift(self, periods, fill_value=None):
"""
Shift Categorical by desired number of periods.
Parameters
----------
periods : int
Number of periods to move, can be positive or negative
fill_value : object, optional
The scalar value to use for newly introduced missing values.
.. versionadded:: 0.24.0
Returns
-------
shifted : Categorical
"""
# since categoricals always have ndim == 1, an axis parameter
# doesn't make any sense here.
codes = self.codes
if codes.ndim > 1:
raise NotImplementedError("Categorical with ndim > 1.")
if np.prod(codes.shape) and (periods != 0):
codes = np.roll(codes, ensure_platform_int(periods), axis=0)
if isna(fill_value):
fill_value = -1
elif fill_value in self.categories:
fill_value = self.categories.get_loc(fill_value)
else:
raise ValueError(
f"'fill_value={fill_value}' is not present "
"in this Categorical's categories"
)
if periods > 0:
codes[:periods] = fill_value
else:
codes[periods:] = fill_value
return self.from_codes(codes, dtype=self.dtype)
def __array__(self, dtype=None) -> np.ndarray:
"""
The numpy array interface.
Returns
-------
numpy.array
A numpy array of either the specified dtype or,
if dtype==None (default), the same dtype as
categorical.categories.dtype.
"""
ret = take_1d(self.categories.values, self._codes)
if dtype and not is_dtype_equal(dtype, self.categories.dtype):
return np.asarray(ret, dtype)
if is_extension_array_dtype(ret):
# When we're a Categorical[ExtensionArray], like Interval,
# we need to ensure __array__ get's all the way to an
# ndarray.
ret = np.asarray(ret)
return ret
def __array_ufunc__(self, ufunc, method, *inputs, **kwargs):
# for binary ops, use our custom dunder methods
result = ops.maybe_dispatch_ufunc_to_dunder_op(
self, ufunc, method, *inputs, **kwargs
)
if result is not NotImplemented:
return result
# for all other cases, raise for now (similarly as what happens in
# Series.__array_prepare__)
raise TypeError(
f"Object with dtype {self.dtype} cannot perform "
f"the numpy op {ufunc.__name__}"
)
def __setstate__(self, state):
"""Necessary for making this object picklable"""
if not isinstance(state, dict):
raise Exception("invalid pickle state")
if "_dtype" not in state:
state["_dtype"] = CategoricalDtype(state["_categories"], state["_ordered"])
for k, v in state.items():
setattr(self, k, v)
@property
def T(self) -> "Categorical":
"""
Return transposed numpy array.
"""
return self
@property
def nbytes(self):
return self._codes.nbytes + self.dtype.categories.values.nbytes
def memory_usage(self, deep=False):
"""
Memory usage of my values
Parameters
----------
deep : bool
Introspect the data deeply, interrogate
`object` dtypes for system-level memory consumption
Returns
-------
bytes used
Notes
-----
Memory usage does not include memory consumed by elements that
are not components of the array if deep=False
See Also
--------
numpy.ndarray.nbytes
"""
return self._codes.nbytes + self.dtype.categories.memory_usage(deep=deep)
@doc(_shared_docs["searchsorted"], klass="Categorical")
def searchsorted(self, value, side="left", sorter=None):
# searchsorted is very performance sensitive. By converting codes
# to same dtype as self.codes, we get much faster performance.
if is_scalar(value):
codes = self.categories.get_loc(value)
codes = self.codes.dtype.type(codes)
else:
locs = [self.categories.get_loc(x) for x in value]
codes = np.array(locs, dtype=self.codes.dtype)
return self.codes.searchsorted(codes, side=side, sorter=sorter)
def isna(self):
"""
Detect missing values
Missing values (-1 in .codes) are detected.
Returns
-------
a boolean array of whether my values are null
See Also
--------
isna : Top-level isna.
isnull : Alias of isna.
Categorical.notna : Boolean inverse of Categorical.isna.
"""
ret = self._codes == -1
return ret
isnull = isna
def notna(self):
"""
Inverse of isna
Both missing values (-1 in .codes) and NA as a category are detected as
null.
Returns
-------
a boolean array of whether my values are not null
See Also
--------
notna : Top-level notna.
notnull : Alias of notna.
Categorical.isna : Boolean inverse of Categorical.notna.
"""
return ~self.isna()
notnull = notna
def dropna(self):
"""
Return the Categorical without null values.
Missing values (-1 in .codes) are detected.
Returns
-------
valid : Categorical
"""
result = self[self.notna()]
return result
def value_counts(self, dropna=True):
"""
Return a Series containing counts of each category.
Every category will have an entry, even those with a count of 0.
Parameters
----------
dropna : bool, default True
Don't include counts of NaN.
Returns
-------
counts : Series
See Also
--------
Series.value_counts
"""
from pandas import Series, CategoricalIndex
code, cat = self._codes, self.categories
ncat, mask = len(cat), 0 <= code
ix, clean = np.arange(ncat), mask.all()
if dropna or clean:
obs = code if clean else code[mask]
count = np.bincount(obs, minlength=ncat or 0)
else:
count = np.bincount(np.where(mask, code, ncat))
ix = np.append(ix, -1)
ix = self._constructor(ix, dtype=self.dtype, fastpath=True)
return Series(count, index=CategoricalIndex(ix), dtype="int64")
def _internal_get_values(self):
"""
Return the values.
For internal compatibility with pandas formatting.
Returns
-------
np.ndarray or Index
A numpy array of the same dtype as categorical.categories.dtype or
Index if datetime / periods.
"""
# if we are a datetime and period index, return Index to keep metadata
if needs_i8_conversion(self.categories):
return self.categories.take(self._codes, fill_value=np.nan)
elif is_integer_dtype(self.categories) and -1 in self._codes:
return self.categories.astype("object").take(self._codes, fill_value=np.nan)
return np.array(self)
def check_for_ordered(self, op):
""" assert that we are ordered """
if not self.ordered:
raise TypeError(
f"Categorical is not ordered for operation {op}\n"
"you can use .as_ordered() to change the "
"Categorical to an ordered one\n"
)
def _values_for_argsort(self):
return self._codes
def argsort(self, ascending=True, kind="quicksort", **kwargs):
"""
Return the indices that would sort the Categorical.
.. versionchanged:: 0.25.0
Changed to sort missing values at the end.
Parameters
----------
ascending : bool, default True
Whether the indices should result in an ascending
or descending sort.
kind : {'quicksort', 'mergesort', 'heapsort'}, optional
Sorting algorithm.
**kwargs:
passed through to :func:`numpy.argsort`.
Returns
-------
numpy.array
See Also
--------
numpy.ndarray.argsort
Notes
-----
While an ordering is applied to the category values, arg-sorting
in this context refers more to organizing and grouping together
based on matching category values. Thus, this function can be
called on an unordered Categorical instance unlike the functions
'Categorical.min' and 'Categorical.max'.
Examples
--------
>>> pd.Categorical(['b', 'b', 'a', 'c']).argsort()
array([2, 0, 1, 3])
>>> cat = pd.Categorical(['b', 'b', 'a', 'c'],
... categories=['c', 'b', 'a'],
... ordered=True)
>>> cat.argsort()
array([3, 0, 1, 2])
Missing values are placed at the end
>>> cat = pd.Categorical([2, None, 1])
>>> cat.argsort()
array([2, 0, 1])
"""
return super().argsort(ascending=ascending, kind=kind, **kwargs)
def sort_values(self, inplace=False, ascending=True, na_position="last"):
"""
Sort the Categorical by category value returning a new
Categorical by default.
While an ordering is applied to the category values, sorting in this
context refers more to organizing and grouping together based on
matching category values. Thus, this function can be called on an
unordered Categorical instance unlike the functions 'Categorical.min'
and 'Categorical.max'.
Parameters
----------
inplace : bool, default False
Do operation in place.
ascending : bool, default True
Order ascending. Passing False orders descending. The
ordering parameter provides the method by which the
category values are organized.
na_position : {'first', 'last'} (optional, default='last')
'first' puts NaNs at the beginning
'last' puts NaNs at the end
Returns
-------
Categorical or None
See Also
--------
Categorical.sort
Series.sort_values
Examples
--------
>>> c = pd.Categorical([1, 2, 2, 1, 5])
>>> c
[1, 2, 2, 1, 5]
Categories (3, int64): [1, 2, 5]
>>> c.sort_values()
[1, 1, 2, 2, 5]
Categories (3, int64): [1, 2, 5]
>>> c.sort_values(ascending=False)
[5, 2, 2, 1, 1]
Categories (3, int64): [1, 2, 5]
Inplace sorting can be done as well:
>>> c.sort_values(inplace=True)
>>> c
[1, 1, 2, 2, 5]
Categories (3, int64): [1, 2, 5]
>>>
>>> c = pd.Categorical([1, 2, 2, 1, 5])
'sort_values' behaviour with NaNs. Note that 'na_position'
is independent of the 'ascending' parameter:
>>> c = pd.Categorical([np.nan, 2, 2, np.nan, 5])
>>> c
[NaN, 2, 2, NaN, 5]
Categories (2, int64): [2, 5]
>>> c.sort_values()
[2, 2, 5, NaN, NaN]
Categories (2, int64): [2, 5]
>>> c.sort_values(ascending=False)
[5, 2, 2, NaN, NaN]
Categories (2, int64): [2, 5]
>>> c.sort_values(na_position='first')
[NaN, NaN, 2, 2, 5]
Categories (2, int64): [2, 5]
>>> c.sort_values(ascending=False, na_position='first')
[NaN, NaN, 5, 2, 2]
Categories (2, int64): [2, 5]
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if na_position not in ["last", "first"]:
raise ValueError(f"invalid na_position: {repr(na_position)}")
sorted_idx = nargsort(self, ascending=ascending, na_position=na_position)
if inplace:
self._codes = self._codes[sorted_idx]
else:
return self._constructor(
values=self._codes[sorted_idx], dtype=self.dtype, fastpath=True
)
def _values_for_rank(self):
"""
For correctly ranking ordered categorical data. See GH#15420
Ordered categorical data should be ranked on the basis of
codes with -1 translated to NaN.
Returns
-------
numpy.array
"""
from pandas import Series
if self.ordered:
values = self.codes
mask = values == -1
if mask.any():
values = values.astype("float64")
values[mask] = np.nan
elif self.categories.is_numeric():
values = np.array(self)
else:
# reorder the categories (so rank can use the float codes)
# instead of passing an object array to rank
values = np.array(
self.rename_categories(Series(self.categories).rank().values)
)
return values
def view(self, dtype=None):
if dtype is not None:
raise NotImplementedError(dtype)
return self._constructor(values=self._codes, dtype=self.dtype, fastpath=True)
def to_dense(self):
"""
Return my 'dense' representation
For internal compatibility with numpy arrays.
Returns
-------
dense : array
"""
warn(
"Categorical.to_dense is deprecated and will be removed in "
"a future version. Use np.asarray(cat) instead.",
FutureWarning,
stacklevel=2,
)
return np.asarray(self)
def fillna(self, value=None, method=None, limit=None):
"""
Fill NA/NaN values using the specified method.
Parameters
----------
value : scalar, dict, Series
If a scalar value is passed it is used to fill all missing values.
Alternatively, a Series or dict can be used to fill in different
values for each index. The value should not be a list. The
value(s) passed should either be in the categories or should be
NaN.
method : {'backfill', 'bfill', 'pad', 'ffill', None}, default None
Method to use for filling holes in reindexed Series
pad / ffill: propagate last valid observation forward to next valid
backfill / bfill: use NEXT valid observation to fill gap
limit : int, default None
(Not implemented yet for Categorical!)
If method is specified, this is the maximum number of consecutive
NaN values to forward/backward fill. In other words, if there is
a gap with more than this number of consecutive NaNs, it will only
be partially filled. If method is not specified, this is the
maximum number of entries along the entire axis where NaNs will be
filled.
Returns
-------
filled : Categorical with NA/NaN filled
"""
value, method = validate_fillna_kwargs(
value, method, validate_scalar_dict_value=False
)
if value is None:
value = np.nan
if limit is not None:
raise NotImplementedError(
"specifying a limit for fillna has not been implemented yet"
)
codes = self._codes
# pad / bfill
if method is not None:
# TODO: dispatch when self.categories is EA-dtype
values = np.asarray(self).reshape(-1, len(self))
values = interpolate_2d(values, method, 0, None, value).astype(
self.categories.dtype
)[0]
codes = _get_codes_for_values(values, self.categories)
else:
# If value is a dict or a Series (a dict value has already
# been converted to a Series)
if isinstance(value, (np.ndarray, Categorical, ABCSeries)):
# We get ndarray or Categorical if called via Series.fillna,
# where it will unwrap another aligned Series before getting here
mask = ~algorithms.isin(value, self.categories)
if not isna(value[mask]).all():
raise ValueError("fill value must be in categories")
values_codes = _get_codes_for_values(value, self.categories)
indexer = np.where(codes == -1)
codes = codes.copy()
codes[indexer] = values_codes[indexer]
# If value is not a dict or Series it should be a scalar
elif is_hashable(value):
if not isna(value) and value not in self.categories:
raise ValueError("fill value must be in categories")
mask = codes == -1
if mask.any():
codes = codes.copy()
if isna(value):
codes[mask] = -1
else:
codes[mask] = self.categories.get_loc(value)
else:
raise TypeError(
f"'value' parameter must be a scalar, dict "
f"or Series, but you passed a {type(value).__name__}"
)
return self._constructor(codes, dtype=self.dtype, fastpath=True)
def take(self, indexer, allow_fill: bool = False, fill_value=None):
"""
Take elements from the Categorical.
Parameters
----------
indexer : sequence of int
The indices in `self` to take. The meaning of negative values in
`indexer` depends on the value of `allow_fill`.
allow_fill : bool, default False
How to handle negative values in `indexer`.
* False: negative values in `indices` indicate positional indices
from the right. This is similar to
:func:`numpy.take`.
* True: negative values in `indices` indicate missing values
(the default). These values are set to `fill_value`. Any other
other negative values raise a ``ValueError``.
.. versionchanged:: 1.0.0
Default value changed from ``True`` to ``False``.
fill_value : object
The value to use for `indices` that are missing (-1), when
``allow_fill=True``. This should be the category, i.e. a value
in ``self.categories``, not a code.
Returns
-------
Categorical
This Categorical will have the same categories and ordered as
`self`.
See Also
--------
Series.take : Similar method for Series.
numpy.ndarray.take : Similar method for NumPy arrays.
Examples
--------
>>> cat = pd.Categorical(['a', 'a', 'b'])
>>> cat
[a, a, b]
Categories (2, object): [a, b]
Specify ``allow_fill==False`` to have negative indices mean indexing
from the right.
>>> cat.take([0, -1, -2], allow_fill=False)
[a, b, a]
Categories (2, object): [a, b]
With ``allow_fill=True``, indices equal to ``-1`` mean "missing"
values that should be filled with the `fill_value`, which is
``np.nan`` by default.
>>> cat.take([0, -1, -1], allow_fill=True)
[a, NaN, NaN]
Categories (2, object): [a, b]
The fill value can be specified.
>>> cat.take([0, -1, -1], allow_fill=True, fill_value='a')
[a, a, a]
Categories (2, object): [a, b]
Specifying a fill value that's not in ``self.categories``
will raise a ``TypeError``.
"""
indexer = np.asarray(indexer, dtype=np.intp)
dtype = self.dtype
if isna(fill_value):
fill_value = -1
elif allow_fill:
# convert user-provided `fill_value` to codes
if fill_value in self.categories:
fill_value = self.categories.get_loc(fill_value)
else:
msg = (
f"'fill_value' ('{fill_value}') is not in this "
"Categorical's categories."
)
raise TypeError(msg)
codes = take(self._codes, indexer, allow_fill=allow_fill, fill_value=fill_value)
result = type(self).from_codes(codes, dtype=dtype)
return result
def take_nd(self, indexer, allow_fill: bool = False, fill_value=None):
# GH#27745 deprecate alias that other EAs dont have
warn(
"Categorical.take_nd is deprecated, use Categorical.take instead",
FutureWarning,
stacklevel=2,
)
return self.take(indexer, allow_fill=allow_fill, fill_value=fill_value)
def __len__(self) -> int:
"""
The length of this Categorical.
"""
return len(self._codes)
def __iter__(self):
"""
Returns an Iterator over the values of this Categorical.
"""
return iter(self._internal_get_values().tolist())
def __contains__(self, key) -> bool:
"""
Returns True if `key` is in this Categorical.
"""
# if key is a NaN, check if any NaN is in self.
if is_scalar(key) and isna(key):
return self.isna().any()
return contains(self, key, container=self._codes)
def _tidy_repr(self, max_vals=10, footer=True) -> str:
"""
a short repr displaying only max_vals and an optional (but default
footer)
"""
num = max_vals // 2
head = self[:num]._get_repr(length=False, footer=False)
tail = self[-(max_vals - num) :]._get_repr(length=False, footer=False)
result = f"{head[:-1]}, ..., {tail[1:]}"
if footer:
result = f"{result}\n{self._repr_footer()}"
return str(result)
def _repr_categories(self):
"""
return the base repr for the categories
"""
max_categories = (
10
if get_option("display.max_categories") == 0
else get_option("display.max_categories")
)
from pandas.io.formats import format as fmt
if len(self.categories) > max_categories:
num = max_categories // 2
head = fmt.format_array(self.categories[:num], None)
tail = fmt.format_array(self.categories[-num:], None)
category_strs = head + ["..."] + tail
else:
category_strs = fmt.format_array(self.categories, None)
# Strip all leading spaces, which format_array adds for columns...
category_strs = [x.strip() for x in category_strs]
return category_strs
def _repr_categories_info(self) -> str:
"""
Returns a string representation of the footer.
"""
category_strs = self._repr_categories()
dtype = str(self.categories.dtype)
levheader = f"Categories ({len(self.categories)}, {dtype}): "
width, height = get_terminal_size()
max_width = get_option("display.width") or width
if console.in_ipython_frontend():
# 0 = no breaks
max_width = 0
levstring = ""
start = True
cur_col_len = len(levheader) # header
sep_len, sep = (3, " < ") if self.ordered else (2, ", ")
linesep = sep.rstrip() + "\n" # remove whitespace
for val in category_strs:
if max_width != 0 and cur_col_len + sep_len + len(val) > max_width:
levstring += linesep + (" " * (len(levheader) + 1))
cur_col_len = len(levheader) + 1 # header + a whitespace
elif not start:
levstring += sep
cur_col_len += len(val)
levstring += val
start = False
# replace to simple save space by
return levheader + "[" + levstring.replace(" < ... < ", " ... ") + "]"
def _repr_footer(self) -> str:
info = self._repr_categories_info()
return f"Length: {len(self)}\n{info}"
def _get_repr(self, length=True, na_rep="NaN", footer=True) -> str:
from pandas.io.formats import format as fmt
formatter = fmt.CategoricalFormatter(
self, length=length, na_rep=na_rep, footer=footer
)
result = formatter.to_string()
return str(result)
def __repr__(self) -> str:
"""
String representation.
"""
_maxlen = 10
if len(self._codes) > _maxlen:
result = self._tidy_repr(_maxlen)
elif len(self._codes) > 0:
result = self._get_repr(length=len(self) > _maxlen)
else:
msg = self._get_repr(length=False, footer=True).replace("\n", ", ")
result = f"[], {msg}"
return result
def _maybe_coerce_indexer(self, indexer):
"""
return an indexer coerced to the codes dtype
"""
if isinstance(indexer, np.ndarray) and indexer.dtype.kind == "i":
indexer = indexer.astype(self._codes.dtype)
return indexer
def __getitem__(self, key):
"""
Return an item.
"""
if isinstance(key, (int, np.integer)):
i = self._codes[key]
if i == -1:
return np.nan
else:
return self.categories[i]
key = check_array_indexer(self, key)
result = self._codes[key]
if result.ndim > 1:
deprecate_ndim_indexing(result)
return result
return self._constructor(result, dtype=self.dtype, fastpath=True)
def __setitem__(self, key, value):
"""
Item assignment.
Raises
------
ValueError
If (one or more) Value is not in categories or if a assigned
`Categorical` does not have the same categories
"""
value = extract_array(value, extract_numpy=True)
# require identical categories set
if isinstance(value, Categorical):
if not is_dtype_equal(self, value):
raise ValueError(
"Cannot set a Categorical with another, "
"without identical categories"
)
if not self.categories.equals(value.categories):
new_codes = recode_for_categories(
value.codes, value.categories, self.categories
)
value = Categorical.from_codes(new_codes, dtype=self.dtype)
rvalue = value if is_list_like(value) else [value]
from pandas import Index
to_add = Index(rvalue).difference(self.categories)
# no assignments of values not in categories, but it's always ok to set
# something to np.nan
if len(to_add) and not isna(to_add).all():
raise ValueError(
"Cannot setitem on a Categorical with a new "
"category, set the categories first"
)
# set by position
if isinstance(key, (int, np.integer)):
pass
# tuple of indexers (dataframe)
elif isinstance(key, tuple):
# only allow 1 dimensional slicing, but can
# in a 2-d case be passd (slice(None),....)
if len(key) == 2:
if not com.is_null_slice(key[0]):
raise AssertionError("invalid slicing for a 1-ndim categorical")
key = key[1]
elif len(key) == 1:
key = key[0]
else:
raise AssertionError("invalid slicing for a 1-ndim categorical")
# slicing in Series or Categorical
elif isinstance(key, slice):
pass
# else: array of True/False in Series or Categorical
lindexer = self.categories.get_indexer(rvalue)
lindexer = self._maybe_coerce_indexer(lindexer)
key = check_array_indexer(self, key)
self._codes[key] = lindexer
def _reverse_indexer(self) -> Dict[Hashable, np.ndarray]:
"""
Compute the inverse of a categorical, returning
a dict of categories -> indexers.
*This is an internal function*
Returns
-------
dict of categories -> indexers
Examples
--------
>>> c = pd.Categorical(list('aabca'))
>>> c
[a, a, b, c, a]
Categories (3, object): [a, b, c]
>>> c.categories
Index(['a', 'b', 'c'], dtype='object')
>>> c.codes
array([0, 0, 1, 2, 0], dtype=int8)
>>> c._reverse_indexer()
{'a': array([0, 1, 4]), 'b': array([2]), 'c': array([3])}
"""
categories = self.categories
r, counts = libalgos.groupsort_indexer(
self.codes.astype("int64"), categories.size
)
counts = counts.cumsum()
_result = (r[start:end] for start, end in zip(counts, counts[1:]))
result = dict(zip(categories, _result))
return result
# reduction ops #
def _reduce(self, name, axis=0, **kwargs):
func = getattr(self, name, None)
if func is None:
raise TypeError(f"Categorical cannot perform the operation {name}")
return func(**kwargs)
@deprecate_kwarg(old_arg_name="numeric_only", new_arg_name="skipna")
def min(self, skipna=True):
"""
The minimum value of the object.
Only ordered `Categoricals` have a minimum!
.. versionchanged:: 1.0.0
Returns an NA value on empty arrays
Raises
------
TypeError
If the `Categorical` is not `ordered`.
Returns
-------
min : the minimum of this `Categorical`
"""
self.check_for_ordered("min")
if not len(self._codes):
return self.dtype.na_value
good = self._codes != -1
if not good.all():
if skipna:
pointer = self._codes[good].min()
else:
return np.nan
else:
pointer = self._codes.min()
return self.categories[pointer]
@deprecate_kwarg(old_arg_name="numeric_only", new_arg_name="skipna")
def max(self, skipna=True):
"""
The maximum value of the object.
Only ordered `Categoricals` have a maximum!
.. versionchanged:: 1.0.0
Returns an NA value on empty arrays
Raises
------
TypeError
If the `Categorical` is not `ordered`.
Returns
-------
max : the maximum of this `Categorical`
"""
self.check_for_ordered("max")
if not len(self._codes):
return self.dtype.na_value
good = self._codes != -1
if not good.all():
if skipna:
pointer = self._codes[good].max()
else:
return np.nan
else:
pointer = self._codes.max()
return self.categories[pointer]
def mode(self, dropna=True):
"""
Returns the mode(s) of the Categorical.
Always returns `Categorical` even if only one value.
Parameters
----------
dropna : bool, default True
Don't consider counts of NaN/NaT.
.. versionadded:: 0.24.0
Returns
-------
modes : `Categorical` (sorted)
"""
codes = self._codes
if dropna:
good = self._codes != -1
codes = self._codes[good]
codes = sorted(htable.mode_int64(ensure_int64(codes), dropna))
return self._constructor(values=codes, dtype=self.dtype, fastpath=True)
def unique(self):
"""
Return the ``Categorical`` which ``categories`` and ``codes`` are
unique. Unused categories are NOT returned.
- unordered category: values and categories are sorted by appearance
order.
- ordered category: values are sorted by appearance order, categories
keeps existing order.
Returns
-------
unique values : ``Categorical``
See Also
--------
pandas.unique
CategoricalIndex.unique
Series.unique
Examples
--------
An unordered Categorical will return categories in the
order of appearance.
>>> pd.Categorical(list("baabc")).unique()
[b, a, c]
Categories (3, object): [b, a, c]
>>> pd.Categorical(list("baabc"), categories=list("abc")).unique()
[b, a, c]
Categories (3, object): [b, a, c]
An ordered Categorical preserves the category ordering.
>>> pd.Categorical(
... list("baabc"), categories=list("abc"), ordered=True
... ).unique()
[b, a, c]
Categories (3, object): [a < b < c]
"""
# unlike np.unique, unique1d does not sort
unique_codes = unique1d(self.codes)
cat = self.copy()
# keep nan in codes
cat._codes = unique_codes
# exclude nan from indexer for categories
take_codes = unique_codes[unique_codes != -1]
if self.ordered:
take_codes = np.sort(take_codes)
return cat.set_categories(cat.categories.take(take_codes))
def _values_for_factorize(self):
codes = self.codes.astype("int64")
return codes, -1
@classmethod
def _from_factorized(cls, uniques, original):
return original._constructor(
original.categories.take(uniques), dtype=original.dtype
)
def equals(self, other):
"""
Returns True if categorical arrays are equal.
Parameters
----------
other : `Categorical`
Returns
-------
bool
"""
if self.is_dtype_equal(other):
if self.categories.equals(other.categories):
# fastpath to avoid re-coding
other_codes = other._codes
else:
other_codes = recode_for_categories(
other.codes, other.categories, self.categories
)
return np.array_equal(self._codes, other_codes)
return False
def is_dtype_equal(self, other):
"""
Returns True if categoricals are the same dtype
same categories, and same ordered
Parameters
----------
other : Categorical
Returns
-------
bool
"""
try:
return hash(self.dtype) == hash(other.dtype)
except (AttributeError, TypeError):
return False
def describe(self):
"""
Describes this Categorical
Returns
-------
description: `DataFrame`
A dataframe with frequency and counts by category.
"""
counts = self.value_counts(dropna=False)
freqs = counts / float(counts.sum())
from pandas.core.reshape.concat import concat
result = concat([counts, freqs], axis=1)
result.columns = ["counts", "freqs"]
result.index.name = "categories"
return result
@Substitution(klass="Categorical")
@Appender(_extension_array_shared_docs["repeat"])
def repeat(self, repeats, axis=None):
nv.validate_repeat(tuple(), dict(axis=axis))
codes = self._codes.repeat(repeats)
return self._constructor(values=codes, dtype=self.dtype, fastpath=True)
# Implement the ExtensionArray interface
@property
def _can_hold_na(self):
return True
@classmethod
def _concat_same_type(self, to_concat):
from pandas.core.dtypes.concat import concat_categorical
return concat_categorical(to_concat)
def isin(self, values):
"""
Check whether `values` are contained in Categorical.
Return a boolean NumPy Array showing whether each element in
the Categorical matches an element in the passed sequence of
`values` exactly.
Parameters
----------
values : set or list-like
The sequence of values to test. Passing in a single string will
raise a ``TypeError``. Instead, turn a single string into a
list of one element.
Returns
-------
isin : numpy.ndarray (bool dtype)
Raises
------
TypeError
* If `values` is not a set or list-like
See Also
--------
pandas.Series.isin : Equivalent method on Series.
Examples
--------
>>> s = pd.Categorical(['lama', 'cow', 'lama', 'beetle', 'lama',
... 'hippo'])
>>> s.isin(['cow', 'lama'])
array([ True, True, True, False, True, False])
Passing a single string as ``s.isin('lama')`` will raise an error. Use
a list of one element instead:
>>> s.isin(['lama'])
array([ True, False, True, False, True, False])
"""
if not is_list_like(values):
values_type = type(values).__name__
raise TypeError(
"only list-like objects are allowed to be passed "
f"to isin(), you passed a [{values_type}]"
)
values = sanitize_array(values, None, None)
null_mask = np.asarray(isna(values))
code_values = self.categories.get_indexer(values)
code_values = code_values[null_mask | (code_values >= 0)]
return algorithms.isin(self.codes, code_values)
def replace(self, to_replace, value, inplace: bool = False):
"""
Replaces all instances of one value with another
Parameters
----------
to_replace: object
The value to be replaced
value: object
The value to replace it with
inplace: bool
Whether the operation is done in-place
Returns
-------
None if inplace is True, otherwise the new Categorical after replacement
Examples
--------
>>> s = pd.Categorical([1, 2, 1, 3])
>>> s.replace(1, 3)
[3, 2, 3, 3]
Categories (2, int64): [2, 3]
"""
inplace = validate_bool_kwarg(inplace, "inplace")
cat = self if inplace else self.copy()
# build a dict of (to replace -> value) pairs
if is_list_like(to_replace):
# if to_replace is list-like and value is scalar
replace_dict = {replace_value: value for replace_value in to_replace}
else:
# if both to_replace and value are scalar
replace_dict = {to_replace: value}
# other cases, like if both to_replace and value are list-like or if
# to_replace is a dict, are handled separately in NDFrame
for replace_value, new_value in replace_dict.items():
if new_value == replace_value:
continue
if replace_value in cat.categories:
if isna(new_value):
cat.remove_categories(replace_value, inplace=True)
continue
categories = cat.categories.tolist()
index = categories.index(replace_value)
if new_value in cat.categories:
value_index = categories.index(new_value)
cat._codes[cat._codes == index] = value_index
cat.remove_categories(replace_value, inplace=True)
else:
categories[index] = new_value
cat.rename_categories(categories, inplace=True)
if not inplace:
return cat
# The Series.cat accessor
@delegate_names(
delegate=Categorical, accessors=["categories", "ordered"], typ="property"
)
@delegate_names(
delegate=Categorical,
accessors=[
"rename_categories",
"reorder_categories",
"add_categories",
"remove_categories",
"remove_unused_categories",
"set_categories",
"as_ordered",
"as_unordered",
],
typ="method",
)
class CategoricalAccessor(PandasDelegate, PandasObject, NoNewAttributesMixin):
"""
Accessor object for categorical properties of the Series values.
Be aware that assigning to `categories` is a inplace operation, while all
methods return new categorical data per default (but can be called with
`inplace=True`).
Parameters
----------
data : Series or CategoricalIndex
Examples
--------
>>> s = pd.Series(list("abbccc")).astype("category")
>>> s
0 a
1 b
2 b
3 c
4 c
5 c
dtype: category
Categories (3, object): [a, b, c]
>>> s.cat.categories
Index(['a', 'b', 'c'], dtype='object')
>>> s.cat.rename_categories(list("cba"))
0 c
1 b
2 b
3 a
4 a
5 a
dtype: category
Categories (3, object): [c, b, a]
>>> s.cat.reorder_categories(list("cba"))
0 a
1 b
2 b
3 c
4 c
5 c
dtype: category
Categories (3, object): [c, b, a]
>>> s.cat.add_categories(["d", "e"])
0 a
1 b
2 b
3 c
4 c
5 c
dtype: category
Categories (5, object): [a, b, c, d, e]
>>> s.cat.remove_categories(["a", "c"])
0 NaN
1 b
2 b
3 NaN
4 NaN
5 NaN
dtype: category
Categories (1, object): [b]
>>> s1 = s.cat.add_categories(["d", "e"])
>>> s1.cat.remove_unused_categories()
0 a
1 b
2 b
3 c
4 c
5 c
dtype: category
Categories (3, object): [a, b, c]
>>> s.cat.set_categories(list("abcde"))
0 a
1 b
2 b
3 c
4 c
5 c
dtype: category
Categories (5, object): [a, b, c, d, e]
>>> s.cat.as_ordered()
0 a
1 b
2 b
3 c
4 c
5 c
dtype: category
Categories (3, object): [a < b < c]
>>> s.cat.as_unordered()
0 a
1 b
2 b
3 c
4 c
5 c
dtype: category
Categories (3, object): [a, b, c]
"""
def __init__(self, data):
self._validate(data)
self._parent = data.values
self._index = data.index
self._name = data.name
self._freeze()
@staticmethod
def _validate(data):
if not is_categorical_dtype(data.dtype):
raise AttributeError("Can only use .cat accessor with a 'category' dtype")
def _delegate_property_get(self, name):
return getattr(self._parent, name)
def _delegate_property_set(self, name, new_values):
return setattr(self._parent, name, new_values)
@property
def codes(self):
"""
Return Series of codes as well as the index.
"""
from pandas import Series
return Series(self._parent.codes, index=self._index)
def _delegate_method(self, name, *args, **kwargs):
from pandas import Series
method = getattr(self._parent, name)
res = method(*args, **kwargs)
if res is not None:
return Series(res, index=self._index, name=self._name)
# utility routines
def _get_codes_for_values(values, categories):
"""
utility routine to turn values into codes given the specified categories
"""
dtype_equal = is_dtype_equal(values.dtype, categories.dtype)
if is_extension_array_dtype(categories.dtype) and is_object_dtype(values):
# Support inferring the correct extension dtype from an array of
# scalar objects. e.g.
# Categorical(array[Period, Period], categories=PeriodIndex(...))
cls = categories.dtype.construct_array_type()
values = maybe_cast_to_extension_array(cls, values)
if not isinstance(values, cls):
# exception raised in _from_sequence
values = ensure_object(values)
categories = ensure_object(categories)
elif not dtype_equal:
values = ensure_object(values)
categories = ensure_object(categories)
hash_klass, vals = _get_data_algo(values)
_, cats = _get_data_algo(categories)
t = hash_klass(len(cats))
t.map_locations(cats)
return coerce_indexer_dtype(t.lookup(vals), cats)
def recode_for_categories(codes: np.ndarray, old_categories, new_categories):
"""
Convert a set of codes for to a new set of categories
Parameters
----------
codes : np.ndarray
old_categories, new_categories : Index
Returns
-------
new_codes : np.ndarray[np.int64]
Examples
--------
>>> old_cat = pd.Index(['b', 'a', 'c'])
>>> new_cat = pd.Index(['a', 'b'])
>>> codes = np.array([0, 1, 1, 2])
>>> recode_for_categories(codes, old_cat, new_cat)
array([ 1, 0, 0, -1], dtype=int8)
"""
if len(old_categories) == 0:
# All null anyway, so just retain the nulls
return codes.copy()
elif new_categories.equals(old_categories):
# Same categories, so no need to actually recode
return codes.copy()
indexer = coerce_indexer_dtype(
new_categories.get_indexer(old_categories), new_categories
)
new_codes = take_1d(indexer, codes.copy(), fill_value=-1)
return new_codes
def _convert_to_list_like(list_like):
if hasattr(list_like, "dtype"):
return list_like
if isinstance(list_like, list):
return list_like
if is_sequence(list_like) or isinstance(list_like, tuple) or is_iterator(list_like):
return list(list_like)
elif is_scalar(list_like):
return [list_like]
else:
# TODO: is this reached?
return [list_like]
def factorize_from_iterable(values):
"""
Factorize an input `values` into `categories` and `codes`. Preserves
categorical dtype in `categories`.
*This is an internal function*
Parameters
----------
values : list-like
Returns
-------
codes : ndarray
categories : Index
If `values` has a categorical dtype, then `categories` is
a CategoricalIndex keeping the categories and order of `values`.
"""
if not is_list_like(values):
raise TypeError("Input must be list-like")
if is_categorical_dtype(values):
values = extract_array(values)
# The Categorical we want to build has the same categories
# as values but its codes are by def [0, ..., len(n_categories) - 1]
cat_codes = np.arange(len(values.categories), dtype=values.codes.dtype)
categories = Categorical.from_codes(cat_codes, dtype=values.dtype)
codes = values.codes
else:
# The value of ordered is irrelevant since we don't use cat as such,
# but only the resulting categories, the order of which is independent
# from ordered. Set ordered to False as default. See GH #15457
cat = Categorical(values, ordered=False)
categories = cat.categories
codes = cat.codes
return codes, categories
def factorize_from_iterables(iterables):
"""
A higher-level wrapper over `factorize_from_iterable`.
*This is an internal function*
Parameters
----------
iterables : list-like of list-likes
Returns
-------
codes_list : list of ndarrays
categories_list : list of Indexes
Notes
-----
See `factorize_from_iterable` for more info.
"""
if len(iterables) == 0:
# For consistency, it should return a list of 2 lists.
return [[], []]
return map(list, zip(*(factorize_from_iterable(it) for it in iterables)))
import operator
from shutil import get_terminal_size
from typing import Dict, Hashable, List, Type, Union, cast
from warnings import warn
import numpy as np
from pandas._config import get_option
from pandas._libs import algos as libalgos, hashtable as htable
from pandas._typing import ArrayLike, Dtype, Ordered, Scalar
from pandas.compat.numpy import function as nv
from pandas.util._decorators import (
Appender,
Substitution,
cache_readonly,
deprecate_kwarg,
doc,
)
from pandas.util._validators import validate_bool_kwarg, validate_fillna_kwargs
from pandas.core.dtypes.cast import (
coerce_indexer_dtype,
maybe_cast_to_extension_array,
maybe_infer_to_datetimelike,
)
from pandas.core.dtypes.common import (
ensure_int64,
ensure_object,
ensure_platform_int,
is_categorical_dtype,
is_datetime64_dtype,
is_dict_like,
is_dtype_equal,
is_extension_array_dtype,
is_integer_dtype,
is_iterator,
is_list_like,
is_object_dtype,
is_scalar,
is_sequence,
is_timedelta64_dtype,
needs_i8_conversion,
)
from pandas.core.dtypes.dtypes import CategoricalDtype
from pandas.core.dtypes.generic import ABCIndexClass, ABCSeries
from pandas.core.dtypes.inference import is_hashable
from pandas.core.dtypes.missing import isna, notna
from pandas.core import ops
from pandas.core.accessor import PandasDelegate, delegate_names
import pandas.core.algorithms as algorithms
from pandas.core.algorithms import _get_data_algo, factorize, take, take_1d, unique1d
from pandas.core.arrays.base import ExtensionArray, _extension_array_shared_docs
from pandas.core.base import NoNewAttributesMixin, PandasObject, _shared_docs
import pandas.core.common as com
from pandas.core.construction import array, extract_array, sanitize_array
from pandas.core.indexers import check_array_indexer, deprecate_ndim_indexing
from pandas.core.missing import interpolate_2d
from pandas.core.ops.common import unpack_zerodim_and_defer
from pandas.core.sorting import nargsort
from pandas.io.formats import console
def _cat_compare_op(op):
opname = f"__{op.__name__}__"
@unpack_zerodim_and_defer(opname)
def func(self, other):
if is_list_like(other) and len(other) != len(self):
# TODO: Could this fail if the categories are listlike objects?
raise ValueError("Lengths must match.")
if not self.ordered:
if opname in ["__lt__", "__gt__", "__le__", "__ge__"]:
raise TypeError(
"Unordered Categoricals can only compare equality or not"
)
if isinstance(other, Categorical):
# Two Categoricals can only be be compared if the categories are
# the same (maybe up to ordering, depending on ordered)
msg = "Categoricals can only be compared if 'categories' are the same."
if len(self.categories) != len(other.categories):
raise TypeError(msg + " Categories are different lengths")
elif self.ordered and not (self.categories == other.categories).all():
raise TypeError(msg)
elif not set(self.categories) == set(other.categories):
raise TypeError(msg)
if not (self.ordered == other.ordered):
raise TypeError(
"Categoricals can only be compared if 'ordered' is the same"
)
if not self.ordered and not self.categories.equals(other.categories):
# both unordered and different order
other_codes = _get_codes_for_values(other, self.categories)
else:
other_codes = other._codes
f = getattr(self._codes, opname)
ret = f(other_codes)
mask = (self._codes == -1) | (other_codes == -1)
if mask.any():
# In other series, the leads to False, so do that here too
if opname == "__ne__":
ret[(self._codes == -1) & (other_codes == -1)] = True
else:
ret[mask] = False
return ret
if is_scalar(other):
if other in self.categories:
i = self.categories.get_loc(other)
ret = getattr(self._codes, opname)(i)
if opname not in {"__eq__", "__ge__", "__gt__"}:
# check for NaN needed if we are not equal or larger
mask = self._codes == -1
ret[mask] = False
return ret
else:
if opname == "__eq__":
return np.zeros(len(self), dtype=bool)
elif opname == "__ne__":
return np.ones(len(self), dtype=bool)
else:
raise TypeError(
f"Cannot compare a Categorical for op {opname} with a "
"scalar, which is not a category."
)
else:
# allow categorical vs object dtype array comparisons for equality
# these are only positional comparisons
if opname in ["__eq__", "__ne__"]:
return getattr(np.array(self), opname)(np.array(other))
raise TypeError(
f"Cannot compare a Categorical for op {opname} with "
f"type {type(other)}.\nIf you want to compare values, "
"use 'np.asarray(cat) <op> other'."
)
func.__name__ = opname
return func
def contains(cat, key, container):
"""
Helper for membership check for ``key`` in ``cat``.
This is a helper method for :method:`__contains__`
and :class:`CategoricalIndex.__contains__`.
Returns True if ``key`` is in ``cat.categories`` and the
location of ``key`` in ``categories`` is in ``container``.
Parameters
----------
cat : :class:`Categorical`or :class:`categoricalIndex`
key : a hashable object
The key to check membership for.
container : Container (e.g. list-like or mapping)
The container to check for membership in.
Returns
-------
is_in : bool
True if ``key`` is in ``self.categories`` and location of
``key`` in ``categories`` is in ``container``, else False.
Notes
-----
This method does not check for NaN values. Do that separately
before calling this method.
"""
hash(key)
# get location of key in categories.
# If a KeyError, the key isn't in categories, so logically
# can't be in container either.
try:
loc = cat.categories.get_loc(key)
except (KeyError, TypeError):
return False
# loc is the location of key in categories, but also the *value*
# for key in container. So, `key` may be in categories,
# but still not in `container`. Example ('b' in categories,
# but not in values):
# 'b' in Categorical(['a'], categories=['a', 'b']) # False
if is_scalar(loc):
return loc in container
else:
# if categories is an IntervalIndex, loc is an array.
return any(loc_ in container for loc_ in loc)
_codes_doc = """
The category codes of this categorical.
Level codes are an array if integer which are the positions of the real
values in the categories array.
There is not setter, use the other categorical methods and the normal item
setter to change values in the categorical.
"""
class Categorical(ExtensionArray, PandasObject):
"""
Represent a categorical variable in classic R / S-plus fashion.
`Categoricals` can only take on only a limited, and usually fixed, number
of possible values (`categories`). In contrast to statistical categorical
variables, a `Categorical` might have an order, but numerical operations
(additions, divisions, ...) are not possible.
All values of the `Categorical` are either in `categories` or `np.nan`.
Assigning values outside of `categories` will raise a `ValueError`. Order
is defined by the order of the `categories`, not lexical order of the
values.
Parameters
----------
values : list-like
The values of the categorical. If categories are given, values not in
categories will be replaced with NaN.
categories : Index-like (unique), optional
The unique categories for this categorical. If not given, the
categories are assumed to be the unique values of `values` (sorted, if
possible, otherwise in the order in which they appear).
ordered : bool, default False
Whether or not this categorical is treated as a ordered categorical.
If True, the resulting categorical will be ordered.
An ordered categorical respects, when sorted, the order of its
`categories` attribute (which in turn is the `categories` argument, if
provided).
dtype : CategoricalDtype
An instance of ``CategoricalDtype`` to use for this categorical.
Attributes
----------
categories : Index
The categories of this categorical
codes : ndarray
The codes (integer positions, which point to the categories) of this
categorical, read only.
ordered : bool
Whether or not this Categorical is ordered.
dtype : CategoricalDtype
The instance of ``CategoricalDtype`` storing the ``categories``
and ``ordered``.
Methods
-------
from_codes
__array__
Raises
------
ValueError
If the categories do not validate.
TypeError
If an explicit ``ordered=True`` is given but no `categories` and the
`values` are not sortable.
See Also
--------
CategoricalDtype : Type for categorical data.
CategoricalIndex : An Index with an underlying ``Categorical``.
Notes
-----
See the `user guide
<https://pandas.pydata.org/pandas-docs/stable/user_guide/categorical.html>`_
for more.
Examples
--------
>>> pd.Categorical([1, 2, 3, 1, 2, 3])
[1, 2, 3, 1, 2, 3]
Categories (3, int64): [1, 2, 3]
>>> pd.Categorical(['a', 'b', 'c', 'a', 'b', 'c'])
[a, b, c, a, b, c]
Categories (3, object): [a, b, c]
Ordered `Categoricals` can be sorted according to the custom order
of the categories and can have a min and max value.
>>> c = pd.Categorical(['a', 'b', 'c', 'a', 'b', 'c'], ordered=True,
... categories=['c', 'b', 'a'])
>>> c
[a, b, c, a, b, c]
Categories (3, object): [c < b < a]
>>> c.min()
'c'
"""
# For comparisons, so that numpy uses our implementation if the compare
# ops, which raise
__array_priority__ = 1000
_dtype = CategoricalDtype(ordered=False)
# tolist is not actually deprecated, just suppressed in the __dir__
_deprecations = PandasObject._deprecations | frozenset(["tolist"])
_typ = "categorical"
def __init__(
self, values, categories=None, ordered=None, dtype=None, fastpath=False
):
dtype = CategoricalDtype._from_values_or_dtype(
values, categories, ordered, dtype
)
# At this point, dtype is always a CategoricalDtype, but
# we may have dtype.categories be None, and we need to
# infer categories in a factorization step further below
if fastpath:
self._codes = coerce_indexer_dtype(values, dtype.categories)
self._dtype = self._dtype.update_dtype(dtype)
return
# null_mask indicates missing values we want to exclude from inference.
# This means: only missing values in list-likes (not arrays/ndframes).
null_mask = np.array(False)
# sanitize input
if is_categorical_dtype(values):
if dtype.categories is None:
dtype = CategoricalDtype(values.categories, dtype.ordered)
elif not isinstance(values, (ABCIndexClass, ABCSeries)):
# sanitize_array coerces np.nan to a string under certain versions
# of numpy
values = maybe_infer_to_datetimelike(values, convert_dates=True)
if not isinstance(values, np.ndarray):
values = _convert_to_list_like(values)
# By convention, empty lists result in object dtype:
sanitize_dtype = "object" if len(values) == 0 else None
null_mask = isna(values)
if null_mask.any():
values = [values[idx] for idx in np.where(~null_mask)[0]]
values = sanitize_array(values, None, dtype=sanitize_dtype)
if dtype.categories is None:
try:
codes, categories = factorize(values, sort=True)
except TypeError as err:
codes, categories = factorize(values, sort=False)
if dtype.ordered:
# raise, as we don't have a sortable data structure and so
# the user should give us one by specifying categories
raise TypeError(
"'values' is not ordered, please "
"explicitly specify the categories order "
"by passing in a categories argument."
) from err
except ValueError as err:
# FIXME
raise NotImplementedError(
"> 1 ndim Categorical are not supported at this time"
) from err
# we're inferring from values
dtype = CategoricalDtype(categories, dtype.ordered)
elif is_categorical_dtype(values):
old_codes = (
values._values.codes if isinstance(values, ABCSeries) else values.codes
)
codes = recode_for_categories(
old_codes, values.dtype.categories, dtype.categories
)
else:
codes = _get_codes_for_values(values, dtype.categories)
if null_mask.any():
# Reinsert -1 placeholders for previously removed missing values
full_codes = -np.ones(null_mask.shape, dtype=codes.dtype)
full_codes[~null_mask] = codes
codes = full_codes
self._dtype = self._dtype.update_dtype(dtype)
self._codes = coerce_indexer_dtype(codes, dtype.categories)
@property
def categories(self):
"""
The categories of this categorical.
Setting assigns new values to each category (effectively a rename of
each individual category).
The assigned value has to be a list-like object. All items must be
unique and the number of items in the new categories must be the same
as the number of items in the old categories.
Assigning to `categories` is a inplace operation!
Raises
------
ValueError
If the new categories do not validate as categories or if the
number of new categories is unequal the number of old categories
See Also
--------
rename_categories : Rename categories.
reorder_categories : Reorder categories.
add_categories : Add new categories.
remove_categories : Remove the specified categories.
remove_unused_categories : Remove categories which are not used.
set_categories : Set the categories to the specified ones.
"""
return self.dtype.categories
@categories.setter
def categories(self, categories):
new_dtype = CategoricalDtype(categories, ordered=self.ordered)
if self.dtype.categories is not None and len(self.dtype.categories) != len(
new_dtype.categories
):
raise ValueError(
"new categories need to have the same number of "
"items as the old categories!"
)
self._dtype = new_dtype
@property
def ordered(self) -> Ordered:
"""
Whether the categories have an ordered relationship.
"""
return self.dtype.ordered
@property
def dtype(self) -> CategoricalDtype:
"""
The :class:`~pandas.api.types.CategoricalDtype` for this instance.
"""
return self._dtype
@property
def _constructor(self) -> Type["Categorical"]:
return Categorical
@classmethod
def _from_sequence(cls, scalars, dtype=None, copy=False):
return Categorical(scalars, dtype=dtype)
def _formatter(self, boxed=False):
# Defer to CategoricalFormatter's formatter.
return None
def copy(self) -> "Categorical":
"""
Copy constructor.
"""
return self._constructor(
values=self._codes.copy(), dtype=self.dtype, fastpath=True
)
def astype(self, dtype: Dtype, copy: bool = True) -> ArrayLike:
"""
Coerce this type to another dtype
Parameters
----------
dtype : numpy dtype or pandas type
copy : bool, default True
By default, astype always returns a newly allocated object.
If copy is set to False and dtype is categorical, the original
object is returned.
"""
if is_categorical_dtype(dtype):
dtype = cast(Union[str, CategoricalDtype], dtype)
# GH 10696/18593
dtype = self.dtype.update_dtype(dtype)
self = self.copy() if copy else self
if dtype == self.dtype:
return self
return self._set_dtype(dtype)
if is_extension_array_dtype(dtype):
return array(self, dtype=dtype, copy=copy) # type: ignore # GH 28770
if is_integer_dtype(dtype) and self.isna().any():
raise ValueError("Cannot convert float NaN to integer")
return np.array(self, dtype=dtype, copy=copy)
@cache_readonly
def size(self) -> int:
"""
Return the len of myself.
"""
return self._codes.size
@cache_readonly
def itemsize(self) -> int:
"""
return the size of a single category
"""
return self.categories.itemsize
def tolist(self) -> List[Scalar]:
"""
Return a list of the values.
These are each a scalar type, which is a Python scalar
(for str, int, float) or a pandas scalar
(for Timestamp/Timedelta/Interval/Period)
"""
return list(self)
to_list = tolist
@classmethod
def _from_inferred_categories(
cls, inferred_categories, inferred_codes, dtype, true_values=None
):
"""
Construct a Categorical from inferred values.
For inferred categories (`dtype` is None) the categories are sorted.
For explicit `dtype`, the `inferred_categories` are cast to the
appropriate type.
Parameters
----------
inferred_categories : Index
inferred_codes : Index
dtype : CategoricalDtype or 'category'
true_values : list, optional
If none are provided, the default ones are
"True", "TRUE", and "true."
Returns
-------
Categorical
"""
from pandas import Index, to_numeric, to_datetime, to_timedelta
cats = Index(inferred_categories)
known_categories = (
isinstance(dtype, CategoricalDtype) and dtype.categories is not None
)
if known_categories:
# Convert to a specialized type with `dtype` if specified.
if dtype.categories.is_numeric():
cats = to_numeric(inferred_categories, errors="coerce")
elif is_datetime64_dtype(dtype.categories):
cats = to_datetime(inferred_categories, errors="coerce")
elif is_timedelta64_dtype(dtype.categories):
cats = to_timedelta(inferred_categories, errors="coerce")
elif dtype.categories.is_boolean():
if true_values is None:
true_values = ["True", "TRUE", "true"]
cats = cats.isin(true_values)
if known_categories:
# Recode from observation order to dtype.categories order.
categories = dtype.categories
codes = recode_for_categories(inferred_codes, cats, categories)
elif not cats.is_monotonic_increasing:
# Sort categories and recode for unknown categories.
unsorted = cats.copy()
categories = cats.sort_values()
codes = recode_for_categories(inferred_codes, unsorted, categories)
dtype = CategoricalDtype(categories, ordered=False)
else:
dtype = CategoricalDtype(cats, ordered=False)
codes = inferred_codes
return cls(codes, dtype=dtype, fastpath=True)
@classmethod
def from_codes(cls, codes, categories=None, ordered=None, dtype=None):
"""
Make a Categorical type from codes and categories or dtype.
This constructor is useful if you already have codes and
categories/dtype and so do not need the (computation intensive)
factorization step, which is usually done on the constructor.
If your data does not follow this convention, please use the normal
constructor.
Parameters
----------
codes : array-like of int
An integer array, where each integer points to a category in
categories or dtype.categories, or else is -1 for NaN.
categories : index-like, optional
The categories for the categorical. Items need to be unique.
If the categories are not given here, then they must be provided
in `dtype`.
ordered : bool, optional
Whether or not this categorical is treated as an ordered
categorical. If not given here or in `dtype`, the resulting
categorical will be unordered.
dtype : CategoricalDtype or "category", optional
If :class:`CategoricalDtype`, cannot be used together with
`categories` or `ordered`.
.. versionadded:: 0.24.0
When `dtype` is provided, neither `categories` nor `ordered`
should be provided.
Returns
-------
Categorical
Examples
--------
>>> dtype = pd.CategoricalDtype(['a', 'b'], ordered=True)
>>> pd.Categorical.from_codes(codes=[0, 1, 0, 1], dtype=dtype)
[a, b, a, b]
Categories (2, object): [a < b]
"""
dtype = CategoricalDtype._from_values_or_dtype(
categories=categories, ordered=ordered, dtype=dtype
)
if dtype.categories is None:
msg = (
"The categories must be provided in 'categories' or "
"'dtype'. Both were None."
)
raise ValueError(msg)
if is_extension_array_dtype(codes) and is_integer_dtype(codes):
# Avoid the implicit conversion of Int to object
if isna(codes).any():
raise ValueError("codes cannot contain NA values")
codes = codes.to_numpy(dtype=np.int64)
else:
codes = np.asarray(codes)
if len(codes) and not is_integer_dtype(codes):
raise ValueError("codes need to be array-like integers")
if len(codes) and (codes.max() >= len(dtype.categories) or codes.min() < -1):
raise ValueError("codes need to be between -1 and len(categories)-1")
return cls(codes, dtype=dtype, fastpath=True)
def _get_codes(self):
"""
Get the codes.
Returns
-------
codes : integer array view
A non writable view of the `codes` array.
"""
v = self._codes.view()
v.flags.writeable = False
return v
def _set_codes(self, codes):
"""
Not settable by the user directly
"""
raise ValueError("cannot set Categorical codes directly")
codes = property(fget=_get_codes, fset=_set_codes, doc=_codes_doc)
def _set_categories(self, categories, fastpath=False):
"""
Sets new categories inplace
Parameters
----------
fastpath : bool, default False
Don't perform validation of the categories for uniqueness or nulls
Examples
--------
>>> c = pd.Categorical(['a', 'b'])
>>> c
[a, b]
Categories (2, object): [a, b]
>>> c._set_categories(pd.Index(['a', 'c']))
>>> c
[a, c]
Categories (2, object): [a, c]
"""
if fastpath:
new_dtype = CategoricalDtype._from_fastpath(categories, self.ordered)
else:
new_dtype = CategoricalDtype(categories, ordered=self.ordered)
if (
not fastpath
and self.dtype.categories is not None
and len(new_dtype.categories) != len(self.dtype.categories)
):
raise ValueError(
"new categories need to have the same number of "
"items than the old categories!"
)
self._dtype = new_dtype
def _set_dtype(self, dtype: CategoricalDtype) -> "Categorical":
"""
Internal method for directly updating the CategoricalDtype
Parameters
----------
dtype : CategoricalDtype
Notes
-----
We don't do any validation here. It's assumed that the dtype is
a (valid) instance of `CategoricalDtype`.
"""
codes = recode_for_categories(self.codes, self.categories, dtype.categories)
return type(self)(codes, dtype=dtype, fastpath=True)
def set_ordered(self, value, inplace=False):
"""
Set the ordered attribute to the boolean value.
Parameters
----------
value : bool
Set whether this categorical is ordered (True) or not (False).
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to the value.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
new_dtype = CategoricalDtype(self.categories, ordered=value)
cat = self if inplace else self.copy()
cat._dtype = new_dtype
if not inplace:
return cat
def as_ordered(self, inplace=False):
"""
Set the Categorical to be ordered.
Parameters
----------
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to True.
Returns
-------
Categorical
Ordered Categorical.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
return self.set_ordered(True, inplace=inplace)
def as_unordered(self, inplace=False):
"""
Set the Categorical to be unordered.
Parameters
----------
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to False.
Returns
-------
Categorical
Unordered Categorical.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
return self.set_ordered(False, inplace=inplace)
def set_categories(self, new_categories, ordered=None, rename=False, inplace=False):
"""
Set the categories to the specified new_categories.
`new_categories` can include new categories (which will result in
unused categories) or remove old categories (which results in values
set to NaN). If `rename==True`, the categories will simple be renamed
(less or more items than in old categories will result in values set to
NaN or in unused categories respectively).
This method can be used to perform more than one action of adding,
removing, and reordering simultaneously and is therefore faster than
performing the individual steps via the more specialised methods.
On the other hand this methods does not do checks (e.g., whether the
old categories are included in the new categories on a reorder), which
can result in surprising changes, for example when using special string
dtypes, which does not considers a S1 string equal to a single char
python string.
Parameters
----------
new_categories : Index-like
The categories in new order.
ordered : bool, default False
Whether or not the categorical is treated as a ordered categorical.
If not given, do not change the ordered information.
rename : bool, default False
Whether or not the new_categories should be considered as a rename
of the old categories or as reordered categories.
inplace : bool, default False
Whether or not to reorder the categories in-place or return a copy
of this categorical with reordered categories.
Returns
-------
Categorical with reordered categories or None if inplace.
Raises
------
ValueError
If new_categories does not validate as categories
See Also
--------
rename_categories : Rename categories.
reorder_categories : Reorder categories.
add_categories : Add new categories.
remove_categories : Remove the specified categories.
remove_unused_categories : Remove categories which are not used.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if ordered is None:
ordered = self.dtype.ordered
new_dtype = CategoricalDtype(new_categories, ordered=ordered)
cat = self if inplace else self.copy()
if rename:
if cat.dtype.categories is not None and len(new_dtype.categories) < len(
cat.dtype.categories
):
# remove all _codes which are larger and set to -1/NaN
cat._codes[cat._codes >= len(new_dtype.categories)] = -1
else:
codes = recode_for_categories(
cat.codes, cat.categories, new_dtype.categories
)
cat._codes = codes
cat._dtype = new_dtype
if not inplace:
return cat
def rename_categories(self, new_categories, inplace=False):
"""
Rename categories.
Parameters
----------
new_categories : list-like, dict-like or callable
New categories which will replace old categories.
* list-like: all items must be unique and the number of items in
the new categories must match the existing number of categories.
* dict-like: specifies a mapping from
old categories to new. Categories not contained in the mapping
are passed through and extra categories in the mapping are
ignored.
* callable : a callable that is called on all items in the old
categories and whose return values comprise the new categories.
.. versionadded:: 0.23.0.
inplace : bool, default False
Whether or not to rename the categories inplace or return a copy of
this categorical with renamed categories.
Returns
-------
cat : Categorical or None
With ``inplace=False``, the new categorical is returned.
With ``inplace=True``, there is no return value.
Raises
------
ValueError
If new categories are list-like and do not have the same number of
items than the current categories or do not validate as categories
See Also
--------
reorder_categories : Reorder categories.
add_categories : Add new categories.
remove_categories : Remove the specified categories.
remove_unused_categories : Remove categories which are not used.
set_categories : Set the categories to the specified ones.
Examples
--------
>>> c = pd.Categorical(['a', 'a', 'b'])
>>> c.rename_categories([0, 1])
[0, 0, 1]
Categories (2, int64): [0, 1]
For dict-like ``new_categories``, extra keys are ignored and
categories not in the dictionary are passed through
>>> c.rename_categories({'a': 'A', 'c': 'C'})
[A, A, b]
Categories (2, object): [A, b]
You may also provide a callable to create the new categories
>>> c.rename_categories(lambda x: x.upper())
[A, A, B]
Categories (2, object): [A, B]
"""
inplace = validate_bool_kwarg(inplace, "inplace")
cat = self if inplace else self.copy()
if is_dict_like(new_categories):
cat.categories = [new_categories.get(item, item) for item in cat.categories]
elif callable(new_categories):
cat.categories = [new_categories(item) for item in cat.categories]
else:
cat.categories = new_categories
if not inplace:
return cat
def reorder_categories(self, new_categories, ordered=None, inplace=False):
"""
Reorder categories as specified in new_categories.
`new_categories` need to include all old categories and no new category
items.
Parameters
----------
new_categories : Index-like
The categories in new order.
ordered : bool, optional
Whether or not the categorical is treated as a ordered categorical.
If not given, do not change the ordered information.
inplace : bool, default False
Whether or not to reorder the categories inplace or return a copy of
this categorical with reordered categories.
Returns
-------
cat : Categorical with reordered categories or None if inplace.
Raises
------
ValueError
If the new categories do not contain all old category items or any
new ones
See Also
--------
rename_categories : Rename categories.
add_categories : Add new categories.
remove_categories : Remove the specified categories.
remove_unused_categories : Remove categories which are not used.
set_categories : Set the categories to the specified ones.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if set(self.dtype.categories) != set(new_categories):
raise ValueError(
"items in new_categories are not the same as in old categories"
)
return self.set_categories(new_categories, ordered=ordered, inplace=inplace)
def add_categories(self, new_categories, inplace=False):
"""
Add new categories.
`new_categories` will be included at the last/highest place in the
categories and will be unused directly after this call.
Parameters
----------
new_categories : category or list-like of category
The new categories to be included.
inplace : bool, default False
Whether or not to add the categories inplace or return a copy of
this categorical with added categories.
Returns
-------
cat : Categorical with new categories added or None if inplace.
Raises
------
ValueError
If the new categories include old categories or do not validate as
categories
See Also
--------
rename_categories : Rename categories.
reorder_categories : Reorder categories.
remove_categories : Remove the specified categories.
remove_unused_categories : Remove categories which are not used.
set_categories : Set the categories to the specified ones.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not is_list_like(new_categories):
new_categories = [new_categories]
already_included = set(new_categories) & set(self.dtype.categories)
if len(already_included) != 0:
raise ValueError(
f"new categories must not include old categories: {already_included}"
)
new_categories = list(self.dtype.categories) + list(new_categories)
new_dtype = CategoricalDtype(new_categories, self.ordered)
cat = self if inplace else self.copy()
cat._dtype = new_dtype
cat._codes = coerce_indexer_dtype(cat._codes, new_dtype.categories)
if not inplace:
return cat
def remove_categories(self, removals, inplace=False):
"""
Remove the specified categories.
`removals` must be included in the old categories. Values which were in
the removed categories will be set to NaN
Parameters
----------
removals : category or list of categories
The categories which should be removed.
inplace : bool, default False
Whether or not to remove the categories inplace or return a copy of
this categorical with removed categories.
Returns
-------
cat : Categorical with removed categories or None if inplace.
Raises
------
ValueError
If the removals are not contained in the categories
See Also
--------
rename_categories : Rename categories.
reorder_categories : Reorder categories.
add_categories : Add new categories.
remove_unused_categories : Remove categories which are not used.
set_categories : Set the categories to the specified ones.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not is_list_like(removals):
removals = [removals]
removal_set = set(removals)
not_included = removal_set - set(self.dtype.categories)
new_categories = [c for c in self.dtype.categories if c not in removal_set]
# GH 10156
if any(isna(removals)):
not_included = {x for x in not_included if notna(x)}
new_categories = [x for x in new_categories if notna(x)]
if len(not_included) != 0:
raise ValueError(f"removals must all be in old categories: {not_included}")
return self.set_categories(
new_categories, ordered=self.ordered, rename=False, inplace=inplace
)
def remove_unused_categories(self, inplace=False):
"""
Remove categories which are not used.
Parameters
----------
inplace : bool, default False
Whether or not to drop unused categories inplace or return a copy of
this categorical with unused categories dropped.
Returns
-------
cat : Categorical with unused categories dropped or None if inplace.
See Also
--------
rename_categories : Rename categories.
reorder_categories : Reorder categories.
add_categories : Add new categories.
remove_categories : Remove the specified categories.
set_categories : Set the categories to the specified ones.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
cat = self if inplace else self.copy()
idx, inv = np.unique(cat._codes, return_inverse=True)
if idx.size != 0 and idx[0] == -1: # na sentinel
idx, inv = idx[1:], inv - 1
new_categories = cat.dtype.categories.take(idx)
new_dtype = CategoricalDtype._from_fastpath(
new_categories, ordered=self.ordered
)
cat._dtype = new_dtype
cat._codes = coerce_indexer_dtype(inv, new_dtype.categories)
if not inplace:
return cat
def map(self, mapper):
"""
Map categories using input correspondence (dict, Series, or function).
Maps the categories to new categories. If the mapping correspondence is
one-to-one the result is a :class:`~pandas.Categorical` which has the
same order property as the original, otherwise a :class:`~pandas.Index`
is returned. NaN values are unaffected.
If a `dict` or :class:`~pandas.Series` is used any unmapped category is
mapped to `NaN`. Note that if this happens an :class:`~pandas.Index`
will be returned.
Parameters
----------
mapper : function, dict, or Series
Mapping correspondence.
Returns
-------
pandas.Categorical or pandas.Index
Mapped categorical.
See Also
--------
CategoricalIndex.map : Apply a mapping correspondence on a
:class:`~pandas.CategoricalIndex`.
Index.map : Apply a mapping correspondence on an
:class:`~pandas.Index`.
Series.map : Apply a mapping correspondence on a
:class:`~pandas.Series`.
Series.apply : Apply more complex functions on a
:class:`~pandas.Series`.
Examples
--------
>>> cat = pd.Categorical(['a', 'b', 'c'])
>>> cat
[a, b, c]
Categories (3, object): [a, b, c]
>>> cat.map(lambda x: x.upper())
[A, B, C]
Categories (3, object): [A, B, C]
>>> cat.map({'a': 'first', 'b': 'second', 'c': 'third'})
[first, second, third]
Categories (3, object): [first, second, third]
If the mapping is one-to-one the ordering of the categories is
preserved:
>>> cat = pd.Categorical(['a', 'b', 'c'], ordered=True)
>>> cat
[a, b, c]
Categories (3, object): [a < b < c]
>>> cat.map({'a': 3, 'b': 2, 'c': 1})
[3, 2, 1]
Categories (3, int64): [3 < 2 < 1]
If the mapping is not one-to-one an :class:`~pandas.Index` is returned:
>>> cat.map({'a': 'first', 'b': 'second', 'c': 'first'})
Index(['first', 'second', 'first'], dtype='object')
If a `dict` is used, all unmapped categories are mapped to `NaN` and
the result is an :class:`~pandas.Index`:
>>> cat.map({'a': 'first', 'b': 'second'})
Index(['first', 'second', nan], dtype='object')
"""
new_categories = self.categories.map(mapper)
try:
return self.from_codes(
self._codes.copy(), categories=new_categories, ordered=self.ordered
)
except ValueError:
# NA values are represented in self._codes with -1
# np.take causes NA values to take final element in new_categories
if np.any(self._codes == -1):
new_categories = new_categories.insert(len(new_categories), np.nan)
return np.take(new_categories, self._codes)
__eq__ = _cat_compare_op(operator.eq)
__ne__ = _cat_compare_op(operator.ne)
__lt__ = _cat_compare_op(operator.lt)
__gt__ = _cat_compare_op(operator.gt)
__le__ = _cat_compare_op(operator.le)
__ge__ = _cat_compare_op(operator.ge)
# for Series/ndarray like compat
@property
def shape(self):
"""
Shape of the Categorical.
For internal compatibility with numpy arrays.
Returns
-------
shape : tuple
"""
return tuple([len(self._codes)])
def shift(self, periods, fill_value=None):
"""
Shift Categorical by desired number of periods.
Parameters
----------
periods : int
Number of periods to move, can be positive or negative
fill_value : object, optional
The scalar value to use for newly introduced missing values.
.. versionadded:: 0.24.0
Returns
-------
shifted : Categorical
"""
# since categoricals always have ndim == 1, an axis parameter
# doesn't make any sense here.
codes = self.codes
if codes.ndim > 1:
raise NotImplementedError("Categorical with ndim > 1.")
if np.prod(codes.shape) and (periods != 0):
codes = np.roll(codes, ensure_platform_int(periods), axis=0)
if isna(fill_value):
fill_value = -1
elif fill_value in self.categories:
fill_value = self.categories.get_loc(fill_value)
else:
raise ValueError(
f"'fill_value={fill_value}' is not present "
"in this Categorical's categories"
)
if periods > 0:
codes[:periods] = fill_value
else:
codes[periods:] = fill_value
return self.from_codes(codes, dtype=self.dtype)
def __array__(self, dtype=None) -> np.ndarray:
"""
The numpy array interface.
Returns
-------
numpy.array
A numpy array of either the specified dtype or,
if dtype==None (default), the same dtype as
categorical.categories.dtype.
"""
ret = take_1d(self.categories.values, self._codes)
if dtype and not is_dtype_equal(dtype, self.categories.dtype):
return np.asarray(ret, dtype)
if is_extension_array_dtype(ret):
# When we're a Categorical[ExtensionArray], like Interval,
# we need to ensure __array__ get's all the way to an
# ndarray.
ret = np.asarray(ret)
return ret
def __array_ufunc__(self, ufunc, method, *inputs, **kwargs):
# for binary ops, use our custom dunder methods
result = ops.maybe_dispatch_ufunc_to_dunder_op(
self, ufunc, method, *inputs, **kwargs
)
if result is not NotImplemented:
return result
# for all other cases, raise for now (similarly as what happens in
# Series.__array_prepare__)
raise TypeError(
f"Object with dtype {self.dtype} cannot perform "
f"the numpy op {ufunc.__name__}"
)
def __setstate__(self, state):
"""Necessary for making this object picklable"""
if not isinstance(state, dict):
raise Exception("invalid pickle state")
if "_dtype" not in state:
state["_dtype"] = CategoricalDtype(state["_categories"], state["_ordered"])
for k, v in state.items():
setattr(self, k, v)
@property
def T(self) -> "Categorical":
"""
Return transposed numpy array.
"""
return self
@property
def nbytes(self):
return self._codes.nbytes + self.dtype.categories.values.nbytes
def memory_usage(self, deep=False):
"""
Memory usage of my values
Parameters
----------
deep : bool
Introspect the data deeply, interrogate
`object` dtypes for system-level memory consumption
Returns
-------
bytes used
Notes
-----
Memory usage does not include memory consumed by elements that
are not components of the array if deep=False
See Also
--------
numpy.ndarray.nbytes
"""
return self._codes.nbytes + self.dtype.categories.memory_usage(deep=deep)
@doc(_shared_docs["searchsorted"], klass="Categorical")
def searchsorted(self, value, side="left", sorter=None):
# searchsorted is very performance sensitive. By converting codes
# to same dtype as self.codes, we get much faster performance.
if is_scalar(value):
codes = self.categories.get_loc(value)
codes = self.codes.dtype.type(codes)
else:
locs = [self.categories.get_loc(x) for x in value]
codes = np.array(locs, dtype=self.codes.dtype)
return self.codes.searchsorted(codes, side=side, sorter=sorter)
def isna(self):
"""
Detect missing values
Missing values (-1 in .codes) are detected.
Returns
-------
a boolean array of whether my values are null
See Also
--------
isna : Top-level isna.
isnull : Alias of isna.
Categorical.notna : Boolean inverse of Categorical.isna.
"""
ret = self._codes == -1
return ret
isnull = isna
def notna(self):
"""
Inverse of isna
Both missing values (-1 in .codes) and NA as a category are detected as
null.
Returns
-------
a boolean array of whether my values are not null
See Also
--------
notna : Top-level notna.
notnull : Alias of notna.
Categorical.isna : Boolean inverse of Categorical.notna.
"""
return ~self.isna()
notnull = notna
def dropna(self):
"""
Return the Categorical without null values.
Missing values (-1 in .codes) are detected.
Returns
-------
valid : Categorical
"""
result = self[self.notna()]
return result
def value_counts(self, dropna=True):
"""
Return a Series containing counts of each category.
Every category will have an entry, even those with a count of 0.
Parameters
----------
dropna : bool, default True
Don't include counts of NaN.
Returns
-------
counts : Series
See Also
--------
Series.value_counts
"""
from pandas import Series, CategoricalIndex
code, cat = self._codes, self.categories
ncat, mask = len(cat), 0 <= code
ix, clean = np.arange(ncat), mask.all()
if dropna or clean:
obs = code if clean else code[mask]
count = np.bincount(obs, minlength=ncat or 0)
else:
count = np.bincount(np.where(mask, code, ncat))
ix = np.append(ix, -1)
ix = self._constructor(ix, dtype=self.dtype, fastpath=True)
return Series(count, index=CategoricalIndex(ix), dtype="int64")
def _internal_get_values(self):
"""
Return the values.
For internal compatibility with pandas formatting.
Returns
-------
np.ndarray or Index
A numpy array of the same dtype as categorical.categories.dtype or
Index if datetime / periods.
"""
# if we are a datetime and period index, return Index to keep metadata
if needs_i8_conversion(self.categories):
return self.categories.take(self._codes, fill_value=np.nan)
elif is_integer_dtype(self.categories) and -1 in self._codes:
return self.categories.astype("object").take(self._codes, fill_value=np.nan)
return np.array(self)
def check_for_ordered(self, op):
""" assert that we are ordered """
if not self.ordered:
raise TypeError(
f"Categorical is not ordered for operation {op}\n"
"you can use .as_ordered() to change the "
"Categorical to an ordered one\n"
)
def _values_for_argsort(self):
return self._codes
def argsort(self, ascending=True, kind="quicksort", **kwargs):
"""
Return the indices that would sort the Categorical.
.. versionchanged:: 0.25.0
Changed to sort missing values at the end.
Parameters
----------
ascending : bool, default True
Whether the indices should result in an ascending
or descending sort.
kind : {'quicksort', 'mergesort', 'heapsort'}, optional
Sorting algorithm.
**kwargs:
passed through to :func:`numpy.argsort`.
Returns
-------
numpy.array
See Also
--------
numpy.ndarray.argsort
Notes
-----
While an ordering is applied to the category values, arg-sorting
in this context refers more to organizing and grouping together
based on matching category values. Thus, this function can be
called on an unordered Categorical instance unlike the functions
'Categorical.min' and 'Categorical.max'.
Examples
--------
>>> pd.Categorical(['b', 'b', 'a', 'c']).argsort()
array([2, 0, 1, 3])
>>> cat = pd.Categorical(['b', 'b', 'a', 'c'],
... categories=['c', 'b', 'a'],
... ordered=True)
>>> cat.argsort()
array([3, 0, 1, 2])
Missing values are placed at the end
>>> cat = pd.Categorical([2, None, 1])
>>> cat.argsort()
array([2, 0, 1])
"""
return super().argsort(ascending=ascending, kind=kind, **kwargs)
def sort_values(self, inplace=False, ascending=True, na_position="last"):
"""
Sort the Categorical by category value returning a new
Categorical by default.
While an ordering is applied to the category values, sorting in this
context refers more to organizing and grouping together based on
matching category values. Thus, this function can be called on an
unordered Categorical instance unlike the functions 'Categorical.min'
and 'Categorical.max'.
Parameters
----------
inplace : bool, default False
Do operation in place.
ascending : bool, default True
Order ascending. Passing False orders descending. The
ordering parameter provides the method by which the
category values are organized.
na_position : {'first', 'last'} (optional, default='last')
'first' puts NaNs at the beginning
'last' puts NaNs at the end
Returns
-------
Categorical or None
See Also
--------
Categorical.sort
Series.sort_values
Examples
--------
>>> c = pd.Categorical([1, 2, 2, 1, 5])
>>> c
[1, 2, 2, 1, 5]
Categories (3, int64): [1, 2, 5]
>>> c.sort_values()
[1, 1, 2, 2, 5]
Categories (3, int64): [1, 2, 5]
>>> c.sort_values(ascending=False)
[5, 2, 2, 1, 1]
Categories (3, int64): [1, 2, 5]
Inplace sorting can be done as well:
>>> c.sort_values(inplace=True)
>>> c
[1, 1, 2, 2, 5]
Categories (3, int64): [1, 2, 5]
>>>
>>> c = pd.Categorical([1, 2, 2, 1, 5])
'sort_values' behaviour with NaNs. Note that 'na_position'
is independent of the 'ascending' parameter:
>>> c = pd.Categorical([np.nan, 2, 2, np.nan, 5])
>>> c
[NaN, 2, 2, NaN, 5]
Categories (2, int64): [2, 5]
>>> c.sort_values()
[2, 2, 5, NaN, NaN]
Categories (2, int64): [2, 5]
>>> c.sort_values(ascending=False)
[5, 2, 2, NaN, NaN]
Categories (2, int64): [2, 5]
>>> c.sort_values(na_position='first')
[NaN, NaN, 2, 2, 5]
Categories (2, int64): [2, 5]
>>> c.sort_values(ascending=False, na_position='first')
[NaN, NaN, 5, 2, 2]
Categories (2, int64): [2, 5]
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if na_position not in ["last", "first"]:
raise ValueError(f"invalid na_position: {repr(na_position)}")
sorted_idx = nargsort(self, ascending=ascending, na_position=na_position)
if inplace:
self._codes = self._codes[sorted_idx]
else:
return self._constructor(
values=self._codes[sorted_idx], dtype=self.dtype, fastpath=True
)
def _values_for_rank(self):
"""
For correctly ranking ordered categorical data. See GH#15420
Ordered categorical data should be ranked on the basis of
codes with -1 translated to NaN.
Returns
-------
numpy.array
"""
from pandas import Series
if self.ordered:
values = self.codes
mask = values == -1
if mask.any():
values = values.astype("float64")
values[mask] = np.nan
elif self.categories.is_numeric():
values = np.array(self)
else:
# reorder the categories (so rank can use the float codes)
# instead of passing an object array to rank
values = np.array(
self.rename_categories(Series(self.categories).rank().values)
)
return values
def view(self, dtype=None):
if dtype is not None:
raise NotImplementedError(dtype)
return self._constructor(values=self._codes, dtype=self.dtype, fastpath=True)
def to_dense(self):
"""
Return my 'dense' representation
For internal compatibility with numpy arrays.
Returns
-------
dense : array
"""
warn(
"Categorical.to_dense is deprecated and will be removed in "
"a future version. Use np.asarray(cat) instead.",
FutureWarning,
stacklevel=2,
)
return np.asarray(self)
def fillna(self, value=None, method=None, limit=None):
"""
Fill NA/NaN values using the specified method.
Parameters
----------
value : scalar, dict, Series
If a scalar value is passed it is used to fill all missing values.
Alternatively, a Series or dict can be used to fill in different
values for each index. The value should not be a list. The
value(s) passed should either be in the categories or should be
NaN.
method : {'backfill', 'bfill', 'pad', 'ffill', None}, default None
Method to use for filling holes in reindexed Series
pad / ffill: propagate last valid observation forward to next valid
backfill / bfill: use NEXT valid observation to fill gap
limit : int, default None
(Not implemented yet for Categorical!)
If method is specified, this is the maximum number of consecutive
NaN values to forward/backward fill. In other words, if there is
a gap with more than this number of consecutive NaNs, it will only
be partially filled. If method is not specified, this is the
maximum number of entries along the entire axis where NaNs will be
filled.
Returns
-------
filled : Categorical with NA/NaN filled
"""
value, method = validate_fillna_kwargs(
value, method, validate_scalar_dict_value=False
)
if value is None:
value = np.nan
if limit is not None:
raise NotImplementedError(
"specifying a limit for fillna has not been implemented yet"
)
codes = self._codes
# pad / bfill
if method is not None:
# TODO: dispatch when self.categories is EA-dtype
values = np.asarray(self).reshape(-1, len(self))
values = interpolate_2d(values, method, 0, None, value).astype(
self.categories.dtype
)[0]
codes = _get_codes_for_values(values, self.categories)
else:
# If value is a dict or a Series (a dict value has already
# been converted to a Series)
if isinstance(value, (np.ndarray, Categorical, ABCSeries)):
# We get ndarray or Categorical if called via Series.fillna,
# where it will unwrap another aligned Series before getting here
mask = ~algorithms.isin(value, self.categories)
if not isna(value[mask]).all():
raise ValueError("fill value must be in categories")
values_codes = _get_codes_for_values(value, self.categories)
indexer = np.where(codes == -1)
codes = codes.copy()
codes[indexer] = values_codes[indexer]
# If value is not a dict or Series it should be a scalar
elif is_hashable(value):
if not isna(value) and value not in self.categories:
raise ValueError("fill value must be in categories")
mask = codes == -1
if mask.any():
codes = codes.copy()
if isna(value):
codes[mask] = -1
else:
codes[mask] = self.categories.get_loc(value)
else:
raise TypeError(
f"'value' parameter must be a scalar, dict "
f"or Series, but you passed a {type(value).__name__}"
)
return self._constructor(codes, dtype=self.dtype, fastpath=True)
def take(self, indexer, allow_fill: bool = False, fill_value=None):
"""
Take elements from the Categorical.
Parameters
----------
indexer : sequence of int
The indices in `self` to take. The meaning of negative values in
`indexer` depends on the value of `allow_fill`.
allow_fill : bool, default False
How to handle negative values in `indexer`.
* False: negative values in `indices` indicate positional indices
from the right. This is similar to
:func:`numpy.take`.
* True: negative values in `indices` indicate missing values
(the default). These values are set to `fill_value`. Any other
other negative values raise a ``ValueError``.
.. versionchanged:: 1.0.0
Default value changed from ``True`` to ``False``.
fill_value : object
The value to use for `indices` that are missing (-1), when
``allow_fill=True``. This should be the category, i.e. a value
in ``self.categories``, not a code.
Returns
-------
Categorical
This Categorical will have the same categories and ordered as
`self`.
See Also
--------
Series.take : Similar method for Series.
numpy.ndarray.take : Similar method for NumPy arrays.
Examples
--------
>>> cat = pd.Categorical(['a', 'a', 'b'])
>>> cat
[a, a, b]
Categories (2, object): [a, b]
Specify ``allow_fill==False`` to have negative indices mean indexing
from the right.
>>> cat.take([0, -1, -2], allow_fill=False)
[a, b, a]
Categories (2, object): [a, b]
With ``allow_fill=True``, indices equal to ``-1`` mean "missing"
values that should be filled with the `fill_value`, which is
``np.nan`` by default.
>>> cat.take([0, -1, -1], allow_fill=True)
[a, NaN, NaN]
Categories (2, object): [a, b]
The fill value can be specified.
>>> cat.take([0, -1, -1], allow_fill=True, fill_value='a')
[a, a, a]
Categories (2, object): [a, b]
Specifying a fill value that's not in ``self.categories``
will raise a ``TypeError``.
"""
indexer = np.asarray(indexer, dtype=np.intp)
dtype = self.dtype
if isna(fill_value):
fill_value = -1
elif allow_fill:
# convert user-provided `fill_value` to codes
if fill_value in self.categories:
fill_value = self.categories.get_loc(fill_value)
else:
msg = (
f"'fill_value' ('{fill_value}') is not in this "
"Categorical's categories."
)
raise TypeError(msg)
codes = take(self._codes, indexer, allow_fill=allow_fill, fill_value=fill_value)
result = type(self).from_codes(codes, dtype=dtype)
return result
def take_nd(self, indexer, allow_fill: bool = False, fill_value=None):
# GH#27745 deprecate alias that other EAs dont have
warn(
"Categorical.take_nd is deprecated, use Categorical.take instead",
FutureWarning,
stacklevel=2,
)
return self.take(indexer, allow_fill=allow_fill, fill_value=fill_value)
def __len__(self) -> int:
"""
The length of this Categorical.
"""
return len(self._codes)
def __iter__(self):
"""
Returns an Iterator over the values of this Categorical.
"""
return iter(self._internal_get_values().tolist())
def __contains__(self, key) -> bool:
"""
Returns True if `key` is in this Categorical.
"""
# if key is a NaN, check if any NaN is in self.
if is_scalar(key) and isna(key):
return self.isna().any()
return contains(self, key, container=self._codes)
def _tidy_repr(self, max_vals=10, footer=True) -> str:
"""
a short repr displaying only max_vals and an optional (but default
footer)
"""
num = max_vals // 2
head = self[:num]._get_repr(length=False, footer=False)
tail = self[-(max_vals - num) :]._get_repr(length=False, footer=False)
result = f"{head[:-1]}, ..., {tail[1:]}"
if footer:
result = f"{result}\n{self._repr_footer()}"
return str(result)
def _repr_categories(self):
"""
return the base repr for the categories
"""
max_categories = (
10
if get_option("display.max_categories") == 0
else get_option("display.max_categories")
)
from pandas.io.formats import format as fmt
if len(self.categories) > max_categories:
num = max_categories // 2
head = fmt.format_array(self.categories[:num], None)
tail = fmt.format_array(self.categories[-num:], None)
category_strs = head + ["..."] + tail
else:
category_strs = fmt.format_array(self.categories, None)
# Strip all leading spaces, which format_array adds for columns...
category_strs = [x.strip() for x in category_strs]
return category_strs
def _repr_categories_info(self) -> str:
"""
Returns a string representation of the footer.
"""
category_strs = self._repr_categories()
dtype = str(self.categories.dtype)
levheader = f"Categories ({len(self.categories)}, {dtype}): "
width, height = get_terminal_size()
max_width = get_option("display.width") or width
if console.in_ipython_frontend():
# 0 = no breaks
max_width = 0
levstring = ""
start = True
cur_col_len = len(levheader) # header
sep_len, sep = (3, " < ") if self.ordered else (2, ", ")
linesep = sep.rstrip() + "\n" # remove whitespace
for val in category_strs:
if max_width != 0 and cur_col_len + sep_len + len(val) > max_width:
levstring += linesep + (" " * (len(levheader) + 1))
cur_col_len = len(levheader) + 1 # header + a whitespace
elif not start:
levstring += sep
cur_col_len += len(val)
levstring += val
start = False
# replace to simple save space by
return levheader + "[" + levstring.replace(" < ... < ", " ... ") + "]"
def _repr_footer(self) -> str:
info = self._repr_categories_info()
return f"Length: {len(self)}\n{info}"
def _get_repr(self, length=True, na_rep="NaN", footer=True) -> str:
from pandas.io.formats import format as fmt
formatter = fmt.CategoricalFormatter(
self, length=length, na_rep=na_rep, footer=footer
)
result = formatter.to_string()
return str(result)
def __repr__(self) -> str:
"""
String representation.
"""
_maxlen = 10
if len(self._codes) > _maxlen:
result = self._tidy_repr(_maxlen)
elif len(self._codes) > 0:
result = self._get_repr(length=len(self) > _maxlen)
else:
msg = self._get_repr(length=False, footer=True).replace("\n", ", ")
result = f"[], {msg}"
return result
def _maybe_coerce_indexer(self, indexer):
"""
return an indexer coerced to the codes dtype
"""
if isinstance(indexer, np.ndarray) and indexer.dtype.kind == "i":
indexer = indexer.astype(self._codes.dtype)
return indexer
def __getitem__(self, key):
"""
Return an item.
"""
if isinstance(key, (int, np.integer)):
i = self._codes[key]
if i == -1:
return np.nan
else:
return self.categories[i]
key = check_array_indexer(self, key)
result = self._codes[key]
if result.ndim > 1:
deprecate_ndim_indexing(result)
return result
return self._constructor(result, dtype=self.dtype, fastpath=True)
def __setitem__(self, key, value):
"""
Item assignment.
Raises
------
ValueError
If (one or more) Value is not in categories or if a assigned
`Categorical` does not have the same categories
"""
value = extract_array(value, extract_numpy=True)
# require identical categories set
if isinstance(value, Categorical):
if not is_dtype_equal(self, value):
raise ValueError(
"Cannot set a Categorical with another, "
"without identical categories"
)
if not self.categories.equals(value.categories):
new_codes = recode_for_categories(
value.codes, value.categories, self.categories
)
value = Categorical.from_codes(new_codes, dtype=self.dtype)
rvalue = value if is_list_like(value) else [value]
from pandas import Index
to_add = Index(rvalue).difference(self.categories)
# no assignments of values not in categories, but it's always ok to set
# something to np.nan
if len(to_add) and not isna(to_add).all():
raise ValueError(
"Cannot setitem on a Categorical with a new "
"category, set the categories first"
)
# set by position
if isinstance(key, (int, np.integer)):
pass
# tuple of indexers (dataframe)
elif isinstance(key, tuple):
# only allow 1 dimensional slicing, but can
# in a 2-d case be passd (slice(None),....)
if len(key) == 2:
if not com.is_null_slice(key[0]):
raise AssertionError("invalid slicing for a 1-ndim categorical")
key = key[1]
elif len(key) == 1:
key = key[0]
else:
raise AssertionError("invalid slicing for a 1-ndim categorical")
# slicing in Series or Categorical
elif isinstance(key, slice):
pass
# else: array of True/False in Series or Categorical
lindexer = self.categories.get_indexer(rvalue)
lindexer = self._maybe_coerce_indexer(lindexer)
key = check_array_indexer(self, key)
self._codes[key] = lindexer
def _reverse_indexer(self) -> Dict[Hashable, np.ndarray]:
"""
Compute the inverse of a categorical, returning
a dict of categories -> indexers.
*This is an internal function*
Returns
-------
dict of categories -> indexers
Examples
--------
>>> c = pd.Categorical(list('aabca'))
>>> c
[a, a, b, c, a]
Categories (3, object): [a, b, c]
>>> c.categories
Index(['a', 'b', 'c'], dtype='object')
>>> c.codes
array([0, 0, 1, 2, 0], dtype=int8)
>>> c._reverse_indexer()
{'a': array([0, 1, 4]), 'b': array([2]), 'c': array([3])}
"""
categories = self.categories
r, counts = libalgos.groupsort_indexer(
self.codes.astype("int64"), categories.size
)
counts = counts.cumsum()
_result = (r[start:end] for start, end in zip(counts, counts[1:]))
result = dict(zip(categories, _result))
return result
# reduction ops #
def _reduce(self, name, axis=0, **kwargs):
func = getattr(self, name, None)
if func is None:
raise TypeError(f"Categorical cannot perform the operation {name}")
return func(**kwargs)
@deprecate_kwarg(old_arg_name="numeric_only", new_arg_name="skipna")
def min(self, skipna=True):
"""
The minimum value of the object.
Only ordered `Categoricals` have a minimum!
.. versionchanged:: 1.0.0
Returns an NA value on empty arrays
Raises
------
TypeError
If the `Categorical` is not `ordered`.
Returns
-------
min : the minimum of this `Categorical`
"""
self.check_for_ordered("min")
if not len(self._codes):
return self.dtype.na_value
good = self._codes != -1
if not good.all():
if skipna and good.any():
pointer = self._codes[good].min()
else:
return np.nan
else:
pointer = self._codes.min()
return self.categories[pointer]
@deprecate_kwarg(old_arg_name="numeric_only", new_arg_name="skipna")
def max(self, skipna=True):
"""
The maximum value of the object.
Only ordered `Categoricals` have a maximum!
.. versionchanged:: 1.0.0
Returns an NA value on empty arrays
Raises
------
TypeError
If the `Categorical` is not `ordered`.
Returns
-------
max : the maximum of this `Categorical`
"""
self.check_for_ordered("max")
if not len(self._codes):
return self.dtype.na_value
good = self._codes != -1
if not good.all():
if skipna and good.any():
pointer = self._codes[good].max()
else:
return np.nan
else:
pointer = self._codes.max()
return self.categories[pointer]
def mode(self, dropna=True):
"""
Returns the mode(s) of the Categorical.
Always returns `Categorical` even if only one value.
Parameters
----------
dropna : bool, default True
Don't consider counts of NaN/NaT.
.. versionadded:: 0.24.0
Returns
-------
modes : `Categorical` (sorted)
"""
codes = self._codes
if dropna:
good = self._codes != -1
codes = self._codes[good]
codes = sorted(htable.mode_int64(ensure_int64(codes), dropna))
return self._constructor(values=codes, dtype=self.dtype, fastpath=True)
def unique(self):
"""
Return the ``Categorical`` which ``categories`` and ``codes`` are
unique. Unused categories are NOT returned.
- unordered category: values and categories are sorted by appearance
order.
- ordered category: values are sorted by appearance order, categories
keeps existing order.
Returns
-------
unique values : ``Categorical``
See Also
--------
pandas.unique
CategoricalIndex.unique
Series.unique
Examples
--------
An unordered Categorical will return categories in the
order of appearance.
>>> pd.Categorical(list("baabc")).unique()
[b, a, c]
Categories (3, object): [b, a, c]
>>> pd.Categorical(list("baabc"), categories=list("abc")).unique()
[b, a, c]
Categories (3, object): [b, a, c]
An ordered Categorical preserves the category ordering.
>>> pd.Categorical(
... list("baabc"), categories=list("abc"), ordered=True
... ).unique()
[b, a, c]
Categories (3, object): [a < b < c]
"""
# unlike np.unique, unique1d does not sort
unique_codes = unique1d(self.codes)
cat = self.copy()
# keep nan in codes
cat._codes = unique_codes
# exclude nan from indexer for categories
take_codes = unique_codes[unique_codes != -1]
if self.ordered:
take_codes = np.sort(take_codes)
return cat.set_categories(cat.categories.take(take_codes))
def _values_for_factorize(self):
codes = self.codes.astype("int64")
return codes, -1
@classmethod
def _from_factorized(cls, uniques, original):
return original._constructor(
original.categories.take(uniques), dtype=original.dtype
)
def equals(self, other):
"""
Returns True if categorical arrays are equal.
Parameters
----------
other : `Categorical`
Returns
-------
bool
"""
if self.is_dtype_equal(other):
if self.categories.equals(other.categories):
# fastpath to avoid re-coding
other_codes = other._codes
else:
other_codes = recode_for_categories(
other.codes, other.categories, self.categories
)
return np.array_equal(self._codes, other_codes)
return False
def is_dtype_equal(self, other):
"""
Returns True if categoricals are the same dtype
same categories, and same ordered
Parameters
----------
other : Categorical
Returns
-------
bool
"""
try:
return hash(self.dtype) == hash(other.dtype)
except (AttributeError, TypeError):
return False
def describe(self):
"""
Describes this Categorical
Returns
-------
description: `DataFrame`
A dataframe with frequency and counts by category.
"""
counts = self.value_counts(dropna=False)
freqs = counts / float(counts.sum())
from pandas.core.reshape.concat import concat
result = concat([counts, freqs], axis=1)
result.columns = ["counts", "freqs"]
result.index.name = "categories"
return result
@Substitution(klass="Categorical")
@Appender(_extension_array_shared_docs["repeat"])
def repeat(self, repeats, axis=None):
nv.validate_repeat(tuple(), dict(axis=axis))
codes = self._codes.repeat(repeats)
return self._constructor(values=codes, dtype=self.dtype, fastpath=True)
# Implement the ExtensionArray interface
@property
def _can_hold_na(self):
return True
@classmethod
def _concat_same_type(self, to_concat):
from pandas.core.dtypes.concat import concat_categorical
return concat_categorical(to_concat)
def isin(self, values):
"""
Check whether `values` are contained in Categorical.
Return a boolean NumPy Array showing whether each element in
the Categorical matches an element in the passed sequence of
`values` exactly.
Parameters
----------
values : set or list-like
The sequence of values to test. Passing in a single string will
raise a ``TypeError``. Instead, turn a single string into a
list of one element.
Returns
-------
isin : numpy.ndarray (bool dtype)
Raises
------
TypeError
* If `values` is not a set or list-like
See Also
--------
pandas.Series.isin : Equivalent method on Series.
Examples
--------
>>> s = pd.Categorical(['lama', 'cow', 'lama', 'beetle', 'lama',
... 'hippo'])
>>> s.isin(['cow', 'lama'])
array([ True, True, True, False, True, False])
Passing a single string as ``s.isin('lama')`` will raise an error. Use
a list of one element instead:
>>> s.isin(['lama'])
array([ True, False, True, False, True, False])
"""
if not is_list_like(values):
values_type = type(values).__name__
raise TypeError(
"only list-like objects are allowed to be passed "
f"to isin(), you passed a [{values_type}]"
)
values = sanitize_array(values, None, None)
null_mask = np.asarray(isna(values))
code_values = self.categories.get_indexer(values)
code_values = code_values[null_mask | (code_values >= 0)]
return algorithms.isin(self.codes, code_values)
def replace(self, to_replace, value, inplace: bool = False):
"""
Replaces all instances of one value with another
Parameters
----------
to_replace: object
The value to be replaced
value: object
The value to replace it with
inplace: bool
Whether the operation is done in-place
Returns
-------
None if inplace is True, otherwise the new Categorical after replacement
Examples
--------
>>> s = pd.Categorical([1, 2, 1, 3])
>>> s.replace(1, 3)
[3, 2, 3, 3]
Categories (2, int64): [2, 3]
"""
inplace = validate_bool_kwarg(inplace, "inplace")
cat = self if inplace else self.copy()
# build a dict of (to replace -> value) pairs
if is_list_like(to_replace):
# if to_replace is list-like and value is scalar
replace_dict = {replace_value: value for replace_value in to_replace}
else:
# if both to_replace and value are scalar
replace_dict = {to_replace: value}
# other cases, like if both to_replace and value are list-like or if
# to_replace is a dict, are handled separately in NDFrame
for replace_value, new_value in replace_dict.items():
if new_value == replace_value:
continue
if replace_value in cat.categories:
if isna(new_value):
cat.remove_categories(replace_value, inplace=True)
continue
categories = cat.categories.tolist()
index = categories.index(replace_value)
if new_value in cat.categories:
value_index = categories.index(new_value)
cat._codes[cat._codes == index] = value_index
cat.remove_categories(replace_value, inplace=True)
else:
categories[index] = new_value
cat.rename_categories(categories, inplace=True)
if not inplace:
return cat
# The Series.cat accessor
@delegate_names(
delegate=Categorical, accessors=["categories", "ordered"], typ="property"
)
@delegate_names(
delegate=Categorical,
accessors=[
"rename_categories",
"reorder_categories",
"add_categories",
"remove_categories",
"remove_unused_categories",
"set_categories",
"as_ordered",
"as_unordered",
],
typ="method",
)
class CategoricalAccessor(PandasDelegate, PandasObject, NoNewAttributesMixin):
"""
Accessor object for categorical properties of the Series values.
Be aware that assigning to `categories` is a inplace operation, while all
methods return new categorical data per default (but can be called with
`inplace=True`).
Parameters
----------
data : Series or CategoricalIndex
Examples
--------
>>> s = pd.Series(list("abbccc")).astype("category")
>>> s
0 a
1 b
2 b
3 c
4 c
5 c
dtype: category
Categories (3, object): [a, b, c]
>>> s.cat.categories
Index(['a', 'b', 'c'], dtype='object')
>>> s.cat.rename_categories(list("cba"))
0 c
1 b
2 b
3 a
4 a
5 a
dtype: category
Categories (3, object): [c, b, a]
>>> s.cat.reorder_categories(list("cba"))
0 a
1 b
2 b
3 c
4 c
5 c
dtype: category
Categories (3, object): [c, b, a]
>>> s.cat.add_categories(["d", "e"])
0 a
1 b
2 b
3 c
4 c
5 c
dtype: category
Categories (5, object): [a, b, c, d, e]
>>> s.cat.remove_categories(["a", "c"])
0 NaN
1 b
2 b
3 NaN
4 NaN
5 NaN
dtype: category
Categories (1, object): [b]
>>> s1 = s.cat.add_categories(["d", "e"])
>>> s1.cat.remove_unused_categories()
0 a
1 b
2 b
3 c
4 c
5 c
dtype: category
Categories (3, object): [a, b, c]
>>> s.cat.set_categories(list("abcde"))
0 a
1 b
2 b
3 c
4 c
5 c
dtype: category
Categories (5, object): [a, b, c, d, e]
>>> s.cat.as_ordered()
0 a
1 b
2 b
3 c
4 c
5 c
dtype: category
Categories (3, object): [a < b < c]
>>> s.cat.as_unordered()
0 a
1 b
2 b
3 c
4 c
5 c
dtype: category
Categories (3, object): [a, b, c]
"""
def __init__(self, data):
self._validate(data)
self._parent = data.values
self._index = data.index
self._name = data.name
self._freeze()
@staticmethod
def _validate(data):
if not is_categorical_dtype(data.dtype):
raise AttributeError("Can only use .cat accessor with a 'category' dtype")
def _delegate_property_get(self, name):
return getattr(self._parent, name)
def _delegate_property_set(self, name, new_values):
return setattr(self._parent, name, new_values)
@property
def codes(self):
"""
Return Series of codes as well as the index.
"""
from pandas import Series
return Series(self._parent.codes, index=self._index)
def _delegate_method(self, name, *args, **kwargs):
from pandas import Series
method = getattr(self._parent, name)
res = method(*args, **kwargs)
if res is not None:
return Series(res, index=self._index, name=self._name)
# utility routines
def _get_codes_for_values(values, categories):
"""
utility routine to turn values into codes given the specified categories
"""
dtype_equal = is_dtype_equal(values.dtype, categories.dtype)
if is_extension_array_dtype(categories.dtype) and is_object_dtype(values):
# Support inferring the correct extension dtype from an array of
# scalar objects. e.g.
# Categorical(array[Period, Period], categories=PeriodIndex(...))
cls = categories.dtype.construct_array_type()
values = maybe_cast_to_extension_array(cls, values)
if not isinstance(values, cls):
# exception raised in _from_sequence
values = ensure_object(values)
categories = ensure_object(categories)
elif not dtype_equal:
values = ensure_object(values)
categories = ensure_object(categories)
hash_klass, vals = _get_data_algo(values)
_, cats = _get_data_algo(categories)
t = hash_klass(len(cats))
t.map_locations(cats)
return coerce_indexer_dtype(t.lookup(vals), cats)
def recode_for_categories(codes: np.ndarray, old_categories, new_categories):
"""
Convert a set of codes for to a new set of categories
Parameters
----------
codes : np.ndarray
old_categories, new_categories : Index
Returns
-------
new_codes : np.ndarray[np.int64]
Examples
--------
>>> old_cat = pd.Index(['b', 'a', 'c'])
>>> new_cat = pd.Index(['a', 'b'])
>>> codes = np.array([0, 1, 1, 2])
>>> recode_for_categories(codes, old_cat, new_cat)
array([ 1, 0, 0, -1], dtype=int8)
"""
if len(old_categories) == 0:
# All null anyway, so just retain the nulls
return codes.copy()
elif new_categories.equals(old_categories):
# Same categories, so no need to actually recode
return codes.copy()
indexer = coerce_indexer_dtype(
new_categories.get_indexer(old_categories), new_categories
)
new_codes = take_1d(indexer, codes.copy(), fill_value=-1)
return new_codes
def _convert_to_list_like(list_like):
if hasattr(list_like, "dtype"):
return list_like
if isinstance(list_like, list):
return list_like
if is_sequence(list_like) or isinstance(list_like, tuple) or is_iterator(list_like):
return list(list_like)
elif is_scalar(list_like):
return [list_like]
else:
# TODO: is this reached?
return [list_like]
def factorize_from_iterable(values):
"""
Factorize an input `values` into `categories` and `codes`. Preserves
categorical dtype in `categories`.
*This is an internal function*
Parameters
----------
values : list-like
Returns
-------
codes : ndarray
categories : Index
If `values` has a categorical dtype, then `categories` is
a CategoricalIndex keeping the categories and order of `values`.
"""
if not is_list_like(values):
raise TypeError("Input must be list-like")
if is_categorical_dtype(values):
values = extract_array(values)
# The Categorical we want to build has the same categories
# as values but its codes are by def [0, ..., len(n_categories) - 1]
cat_codes = np.arange(len(values.categories), dtype=values.codes.dtype)
categories = Categorical.from_codes(cat_codes, dtype=values.dtype)
codes = values.codes
else:
# The value of ordered is irrelevant since we don't use cat as such,
# but only the resulting categories, the order of which is independent
# from ordered. Set ordered to False as default. See GH #15457
cat = Categorical(values, ordered=False)
categories = cat.categories
codes = cat.codes
return codes, categories
def factorize_from_iterables(iterables):
"""
A higher-level wrapper over `factorize_from_iterable`.
*This is an internal function*
Parameters
----------
iterables : list-like of list-likes
Returns
-------
codes_list : list of ndarrays
categories_list : list of Indexes
Notes
-----
See `factorize_from_iterable` for more info.
"""
if len(iterables) == 0:
# For consistency, it should return a list of 2 lists.
return [[], []]
return map(list, zip(*(factorize_from_iterable(it) for it in iterables)))
| BugsInPy/BugsInPy/temp/projects/pandas/bug-26-fixed/pandas/pandas/core/arrays/categorical.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-26-buggy/pandas/pandas/core/arrays/categorical.py |
pandas-bug-64 | """
Utilities for conversion to writer-agnostic Excel representation.
"""
from functools import reduce
import itertools
import re
from typing import Callable, Dict, Optional, Sequence, Union
import warnings
import numpy as np
from pandas._typing import Label
from pandas.core.dtypes import missing
from pandas.core.dtypes.common import is_float, is_scalar
from pandas.core.dtypes.generic import ABCIndex, ABCMultiIndex, ABCPeriodIndex
from pandas import Index
import pandas.core.common as com
from pandas.io.common import stringify_path
from pandas.io.formats.css import CSSResolver, CSSWarning
from pandas.io.formats.format import get_level_lengths
from pandas.io.formats.printing import pprint_thing
class ExcelCell:
__fields__ = ("row", "col", "val", "style", "mergestart", "mergeend")
__slots__ = __fields__
def __init__(
self, row: int, col: int, val, style=None, mergestart=None, mergeend=None
):
self.row = row
self.col = col
self.val = val
self.style = style
self.mergestart = mergestart
self.mergeend = mergeend
class CSSToExcelConverter:
"""A callable for converting CSS declarations to ExcelWriter styles
Supports parts of CSS 2.2, with minimal CSS 3.0 support (e.g. text-shadow),
focusing on font styling, backgrounds, borders and alignment.
Operates by first computing CSS styles in a fairly generic
way (see :meth:`compute_css`) then determining Excel style
properties from CSS properties (see :meth:`build_xlstyle`).
Parameters
----------
inherited : str, optional
CSS declarations understood to be the containing scope for the
CSS processed by :meth:`__call__`.
"""
# NB: Most of the methods here could be classmethods, as only __init__
# and __call__ make use of instance attributes. We leave them as
# instancemethods so that users can easily experiment with extensions
# without monkey-patching.
def __init__(self, inherited: Optional[str] = None):
if inherited is not None:
inherited = self.compute_css(inherited)
self.inherited = inherited
compute_css = CSSResolver()
def __call__(self, declarations_str: str) -> Dict[str, Dict[str, str]]:
"""
Convert CSS declarations to ExcelWriter style.
Parameters
----------
declarations_str : str
List of CSS declarations.
e.g. "font-weight: bold; background: blue"
Returns
-------
xlstyle : dict
A style as interpreted by ExcelWriter when found in
ExcelCell.style.
"""
# TODO: memoize?
properties = self.compute_css(declarations_str, self.inherited)
return self.build_xlstyle(properties)
def build_xlstyle(self, props: Dict[str, str]) -> Dict[str, Dict[str, str]]:
out = {
"alignment": self.build_alignment(props),
"border": self.build_border(props),
"fill": self.build_fill(props),
"font": self.build_font(props),
"number_format": self.build_number_format(props),
}
# TODO: handle cell width and height: needs support in pandas.io.excel
def remove_none(d: Dict[str, str]) -> None:
"""Remove key where value is None, through nested dicts"""
for k, v in list(d.items()):
if v is None:
del d[k]
elif isinstance(v, dict):
remove_none(v)
if not v:
del d[k]
remove_none(out)
return out
VERTICAL_MAP = {
"top": "top",
"text-top": "top",
"middle": "center",
"baseline": "bottom",
"bottom": "bottom",
"text-bottom": "bottom",
# OpenXML also has 'justify', 'distributed'
}
def build_alignment(self, props) -> Dict[str, Optional[Union[bool, str]]]:
# TODO: text-indent, padding-left -> alignment.indent
return {
"horizontal": props.get("text-align"),
"vertical": self.VERTICAL_MAP.get(props.get("vertical-align")),
"wrap_text": (
None
if props.get("white-space") is None
else props["white-space"] not in ("nowrap", "pre", "pre-line")
),
}
def build_border(self, props: Dict) -> Dict[str, Dict[str, str]]:
return {
side: {
"style": self._border_style(
props.get(f"border-{side}-style"),
props.get(f"border-{side}-width"),
),
"color": self.color_to_excel(props.get(f"border-{side}-color")),
}
for side in ["top", "right", "bottom", "left"]
}
def _border_style(self, style: Optional[str], width):
# convert styles and widths to openxml, one of:
# 'dashDot'
# 'dashDotDot'
# 'dashed'
# 'dotted'
# 'double'
# 'hair'
# 'medium'
# 'mediumDashDot'
# 'mediumDashDotDot'
# 'mediumDashed'
# 'slantDashDot'
# 'thick'
# 'thin'
if width is None and style is None:
return None
if style == "none" or style == "hidden":
return None
if width is None:
width = "2pt"
width = float(width[:-2])
if width < 1e-5:
return None
elif width < 1.3:
width_name = "thin"
elif width < 2.8:
width_name = "medium"
else:
width_name = "thick"
if style in (None, "groove", "ridge", "inset", "outset"):
# not handled
style = "solid"
if style == "double":
return "double"
if style == "solid":
return width_name
if style == "dotted":
if width_name in ("hair", "thin"):
return "dotted"
return "mediumDashDotDot"
if style == "dashed":
if width_name in ("hair", "thin"):
return "dashed"
return "mediumDashed"
def build_fill(self, props: Dict[str, str]):
# TODO: perhaps allow for special properties
# -excel-pattern-bgcolor and -excel-pattern-type
fill_color = props.get("background-color")
if fill_color not in (None, "transparent", "none"):
return {"fgColor": self.color_to_excel(fill_color), "patternType": "solid"}
BOLD_MAP = {
"bold": True,
"bolder": True,
"600": True,
"700": True,
"800": True,
"900": True,
"normal": False,
"lighter": False,
"100": False,
"200": False,
"300": False,
"400": False,
"500": False,
}
ITALIC_MAP = {"normal": False, "italic": True, "oblique": True}
def build_font(self, props) -> Dict[str, Optional[Union[bool, int, str]]]:
size = props.get("font-size")
if size is not None:
assert size.endswith("pt")
size = float(size[:-2])
font_names_tmp = re.findall(
r"""(?x)
(
"(?:[^"]|\\")+"
|
'(?:[^']|\\')+'
|
[^'",]+
)(?=,|\s*$)
""",
props.get("font-family", ""),
)
font_names = []
for name in font_names_tmp:
if name[:1] == '"':
name = name[1:-1].replace('\\"', '"')
elif name[:1] == "'":
name = name[1:-1].replace("\\'", "'")
else:
name = name.strip()
if name:
font_names.append(name)
family = None
for name in font_names:
if name == "serif":
family = 1 # roman
break
elif name == "sans-serif":
family = 2 # swiss
break
elif name == "cursive":
family = 4 # script
break
elif name == "fantasy":
family = 5 # decorative
break
decoration = props.get("text-decoration")
if decoration is not None:
decoration = decoration.split()
else:
decoration = ()
return {
"name": font_names[0] if font_names else None,
"family": family,
"size": size,
"bold": self.BOLD_MAP.get(props.get("font-weight")),
"italic": self.ITALIC_MAP.get(props.get("font-style")),
"underline": ("single" if "underline" in decoration else None),
"strike": ("line-through" in decoration) or None,
"color": self.color_to_excel(props.get("color")),
# shadow if nonzero digit before shadow color
"shadow": (
bool(re.search("^[^#(]*[1-9]", props["text-shadow"]))
if "text-shadow" in props
else None
),
# FIXME: dont leave commented-out
# 'vertAlign':,
# 'charset': ,
# 'scheme': ,
# 'outline': ,
# 'condense': ,
}
NAMED_COLORS = {
"maroon": "800000",
"brown": "A52A2A",
"red": "FF0000",
"pink": "FFC0CB",
"orange": "FFA500",
"yellow": "FFFF00",
"olive": "808000",
"green": "008000",
"purple": "800080",
"fuchsia": "FF00FF",
"lime": "00FF00",
"teal": "008080",
"aqua": "00FFFF",
"blue": "0000FF",
"navy": "000080",
"black": "000000",
"gray": "808080",
"grey": "808080",
"silver": "C0C0C0",
"white": "FFFFFF",
}
def color_to_excel(self, val: Optional[str]):
if val is None:
return None
if val.startswith("#") and len(val) == 7:
return val[1:].upper()
if val.startswith("#") and len(val) == 4:
return (val[1] * 2 + val[2] * 2 + val[3] * 2).upper()
try:
return self.NAMED_COLORS[val]
except KeyError:
warnings.warn(f"Unhandled color format: {repr(val)}", CSSWarning)
def build_number_format(self, props: Dict) -> Dict[str, Optional[str]]:
return {"format_code": props.get("number-format")}
class ExcelFormatter:
"""
Class for formatting a DataFrame to a list of ExcelCells,
Parameters
----------
df : DataFrame or Styler
na_rep: na representation
float_format : string, default None
Format string for floating point numbers
cols : sequence, optional
Columns to write
header : boolean or list of string, default True
Write out column names. If a list of string is given it is
assumed to be aliases for the column names
index : boolean, default True
output row names (index)
index_label : string or sequence, default None
Column label for index column(s) if desired. If None is given, and
`header` and `index` are True, then the index names are used. A
sequence should be given if the DataFrame uses MultiIndex.
merge_cells : boolean, default False
Format MultiIndex and Hierarchical Rows as merged cells.
inf_rep : string, default `'inf'`
representation for np.inf values (which aren't representable in Excel)
A `'-'` sign will be added in front of -inf.
style_converter : callable, optional
This translates Styler styles (CSS) into ExcelWriter styles.
Defaults to ``CSSToExcelConverter()``.
It should have signature css_declarations string -> excel style.
This is only called for body cells.
"""
max_rows = 2 ** 20
max_cols = 2 ** 14
def __init__(
self,
df,
na_rep: str = "",
float_format: Optional[str] = None,
cols: Optional[Sequence[Label]] = None,
header: Union[Sequence[Label], bool] = True,
index: bool = True,
index_label: Optional[Union[Label, Sequence[Label]]] = None,
merge_cells: bool = False,
inf_rep: str = "inf",
style_converter: Optional[Callable] = None,
):
self.rowcounter = 0
self.na_rep = na_rep
if hasattr(df, "render"):
self.styler = df
df = df.data
if style_converter is None:
style_converter = CSSToExcelConverter()
self.style_converter = style_converter
else:
self.styler = None
self.df = df
if cols is not None:
# all missing, raise
if not len(Index(cols) & df.columns):
raise KeyError("passes columns are not ALL present dataframe")
if len(Index(cols) & df.columns) != len(cols):
# Deprecated in GH#17295, enforced in 1.0.0
raise KeyError("Not all names specified in 'columns' are found")
self.df = df
self.columns = self.df.columns
self.float_format = float_format
self.index = index
self.index_label = index_label
self.header = header
self.merge_cells = merge_cells
self.inf_rep = inf_rep
@property
def header_style(self):
return {
"font": {"bold": True},
"borders": {
"top": "thin",
"right": "thin",
"bottom": "thin",
"left": "thin",
},
"alignment": {"horizontal": "center", "vertical": "top"},
}
def _format_value(self, val):
if is_scalar(val) and missing.isna(val):
val = self.na_rep
elif is_float(val):
if missing.isposinf_scalar(val):
val = self.inf_rep
elif missing.isneginf_scalar(val):
val = f"-{self.inf_rep}"
elif self.float_format is not None:
val = float(self.float_format % val)
if getattr(val, "tzinfo", None) is not None:
raise ValueError(
"Excel does not support datetimes with "
"timezones. Please ensure that datetimes "
"are timezone unaware before writing to Excel."
)
return val
def _format_header_mi(self):
if self.columns.nlevels > 1:
if not self.index:
raise NotImplementedError(
"Writing to Excel with MultiIndex columns and no "
"index ('index'=False) is not yet implemented."
)
has_aliases = isinstance(self.header, (tuple, list, np.ndarray, ABCIndex))
if not (has_aliases or self.header):
return
columns = self.columns
level_strs = columns.format(
sparsify=self.merge_cells, adjoin=False, names=False
)
level_lengths = get_level_lengths(level_strs)
coloffset = 0
lnum = 0
if self.index and isinstance(self.df.index, ABCMultiIndex):
coloffset = len(self.df.index[0]) - 1
if self.merge_cells:
# Format multi-index as a merged cells.
for lnum in range(len(level_lengths)):
name = columns.names[lnum]
yield ExcelCell(lnum, coloffset, name, self.header_style)
for lnum, (spans, levels, level_codes) in enumerate(
zip(level_lengths, columns.levels, columns.codes)
):
values = levels.take(level_codes)
for i in spans:
if spans[i] > 1:
yield ExcelCell(
lnum,
coloffset + i + 1,
values[i],
self.header_style,
lnum,
coloffset + i + spans[i],
)
else:
yield ExcelCell(
lnum, coloffset + i + 1, values[i], self.header_style
)
else:
# Format in legacy format with dots to indicate levels.
for i, values in enumerate(zip(*level_strs)):
v = ".".join(map(pprint_thing, values))
yield ExcelCell(lnum, coloffset + i + 1, v, self.header_style)
self.rowcounter = lnum
def _format_header_regular(self):
has_aliases = isinstance(self.header, (tuple, list, np.ndarray, ABCIndex))
if has_aliases or self.header:
coloffset = 0
if self.index:
coloffset = 1
if isinstance(self.df.index, ABCMultiIndex):
coloffset = len(self.df.index[0])
colnames = self.columns
if has_aliases:
if len(self.header) != len(self.columns):
raise ValueError(
f"Writing {len(self.columns)} cols but got {len(self.header)} "
"aliases"
)
else:
colnames = self.header
for colindex, colname in enumerate(colnames):
yield ExcelCell(
self.rowcounter, colindex + coloffset, colname, self.header_style
)
def _format_header(self):
if isinstance(self.columns, ABCMultiIndex):
gen = self._format_header_mi()
else:
gen = self._format_header_regular()
gen2 = ()
if self.df.index.names:
row = [x if x is not None else "" for x in self.df.index.names] + [
""
] * len(self.columns)
if reduce(lambda x, y: x and y, map(lambda x: x != "", row)):
gen2 = (
ExcelCell(self.rowcounter, colindex, val, self.header_style)
for colindex, val in enumerate(row)
)
self.rowcounter += 1
return itertools.chain(gen, gen2)
def _format_body(self):
if isinstance(self.df.index, ABCMultiIndex):
return self._format_hierarchical_rows()
else:
return self._format_regular_rows()
def _format_regular_rows(self):
has_aliases = isinstance(self.header, (tuple, list, np.ndarray, ABCIndex))
if has_aliases or self.header:
self.rowcounter += 1
# output index and index_label?
if self.index:
# check aliases
# if list only take first as this is not a MultiIndex
if self.index_label and isinstance(
self.index_label, (list, tuple, np.ndarray, Index)
):
index_label = self.index_label[0]
# if string good to go
elif self.index_label and isinstance(self.index_label, str):
index_label = self.index_label
else:
index_label = self.df.index.names[0]
if isinstance(self.columns, ABCMultiIndex):
self.rowcounter += 1
if index_label and self.header is not False:
yield ExcelCell(self.rowcounter - 1, 0, index_label, self.header_style)
# write index_values
index_values = self.df.index
if isinstance(self.df.index, ABCPeriodIndex):
index_values = self.df.index.to_timestamp()
for idx, idxval in enumerate(index_values):
yield ExcelCell(self.rowcounter + idx, 0, idxval, self.header_style)
coloffset = 1
else:
coloffset = 0
for cell in self._generate_body(coloffset):
yield cell
def _format_hierarchical_rows(self):
has_aliases = isinstance(self.header, (tuple, list, np.ndarray, ABCIndex))
if has_aliases or self.header:
self.rowcounter += 1
gcolidx = 0
if self.index:
index_labels = self.df.index.names
# check for aliases
if self.index_label and isinstance(
self.index_label, (list, tuple, np.ndarray, Index)
):
index_labels = self.index_label
# MultiIndex columns require an extra row
# with index names (blank if None) for
# unambiguous round-trip, unless not merging,
# in which case the names all go on one row Issue #11328
if isinstance(self.columns, ABCMultiIndex) and self.merge_cells:
self.rowcounter += 1
# if index labels are not empty go ahead and dump
if com.any_not_none(*index_labels) and self.header is not False:
for cidx, name in enumerate(index_labels):
yield ExcelCell(self.rowcounter - 1, cidx, name, self.header_style)
if self.merge_cells:
# Format hierarchical rows as merged cells.
level_strs = self.df.index.format(
sparsify=True, adjoin=False, names=False
)
level_lengths = get_level_lengths(level_strs)
for spans, levels, level_codes in zip(
level_lengths, self.df.index.levels, self.df.index.codes
):
values = levels.take(
level_codes, allow_fill=levels._can_hold_na, fill_value=True
)
for i in spans:
if spans[i] > 1:
yield ExcelCell(
self.rowcounter + i,
gcolidx,
values[i],
self.header_style,
self.rowcounter + i + spans[i] - 1,
gcolidx,
)
else:
yield ExcelCell(
self.rowcounter + i,
gcolidx,
values[i],
self.header_style,
)
gcolidx += 1
else:
# Format hierarchical rows with non-merged values.
for indexcolvals in zip(*self.df.index):
for idx, indexcolval in enumerate(indexcolvals):
yield ExcelCell(
self.rowcounter + idx,
gcolidx,
indexcolval,
self.header_style,
)
gcolidx += 1
for cell in self._generate_body(gcolidx):
yield cell
def _generate_body(self, coloffset: int):
if self.styler is None:
styles = None
else:
styles = self.styler._compute().ctx
if not styles:
styles = None
xlstyle = None
# Write the body of the frame data series by series.
for colidx in range(len(self.columns)):
series = self.df.iloc[:, colidx]
for i, val in enumerate(series):
if styles is not None:
xlstyle = self.style_converter(";".join(styles[i, colidx]))
yield ExcelCell(self.rowcounter + i, colidx + coloffset, val, xlstyle)
def get_formatted_cells(self):
for cell in itertools.chain(self._format_header(), self._format_body()):
cell.val = self._format_value(cell.val)
yield cell
def write(
self,
writer,
sheet_name="Sheet1",
startrow=0,
startcol=0,
freeze_panes=None,
engine=None,
):
"""
writer : string or ExcelWriter object
File path or existing ExcelWriter
sheet_name : string, default 'Sheet1'
Name of sheet which will contain DataFrame
startrow :
upper left cell row to dump data frame
startcol :
upper left cell column to dump data frame
freeze_panes : tuple of integer (length 2), default None
Specifies the one-based bottommost row and rightmost column that
is to be frozen
engine : string, default None
write engine to use if writer is a path - you can also set this
via the options ``io.excel.xlsx.writer``, ``io.excel.xls.writer``,
and ``io.excel.xlsm.writer``.
"""
from pandas.io.excel import ExcelWriter
num_rows, num_cols = self.df.shape
if num_rows > self.max_rows or num_cols > self.max_cols:
raise ValueError(
f"This sheet is too large! Your sheet size is: {num_rows}, {num_cols} "
f"Max sheet size is: {self.max_rows}, {self.max_cols}"
)
if isinstance(writer, ExcelWriter):
need_save = False
else:
writer = ExcelWriter(stringify_path(writer), engine=engine)
need_save = True
formatted_cells = self.get_formatted_cells()
writer.write_cells(
formatted_cells,
sheet_name,
startrow=startrow,
startcol=startcol,
freeze_panes=freeze_panes,
)
if need_save:
writer.save()
"""
Utilities for conversion to writer-agnostic Excel representation.
"""
from functools import reduce
import itertools
import re
from typing import Callable, Dict, Optional, Sequence, Union
import warnings
import numpy as np
from pandas._typing import Label
from pandas.core.dtypes import missing
from pandas.core.dtypes.common import is_float, is_scalar
from pandas.core.dtypes.generic import ABCIndex, ABCMultiIndex, ABCPeriodIndex
from pandas import Index
import pandas.core.common as com
from pandas.io.common import stringify_path
from pandas.io.formats.css import CSSResolver, CSSWarning
from pandas.io.formats.format import get_level_lengths
from pandas.io.formats.printing import pprint_thing
class ExcelCell:
__fields__ = ("row", "col", "val", "style", "mergestart", "mergeend")
__slots__ = __fields__
def __init__(
self, row: int, col: int, val, style=None, mergestart=None, mergeend=None
):
self.row = row
self.col = col
self.val = val
self.style = style
self.mergestart = mergestart
self.mergeend = mergeend
class CSSToExcelConverter:
"""A callable for converting CSS declarations to ExcelWriter styles
Supports parts of CSS 2.2, with minimal CSS 3.0 support (e.g. text-shadow),
focusing on font styling, backgrounds, borders and alignment.
Operates by first computing CSS styles in a fairly generic
way (see :meth:`compute_css`) then determining Excel style
properties from CSS properties (see :meth:`build_xlstyle`).
Parameters
----------
inherited : str, optional
CSS declarations understood to be the containing scope for the
CSS processed by :meth:`__call__`.
"""
# NB: Most of the methods here could be classmethods, as only __init__
# and __call__ make use of instance attributes. We leave them as
# instancemethods so that users can easily experiment with extensions
# without monkey-patching.
def __init__(self, inherited: Optional[str] = None):
if inherited is not None:
inherited = self.compute_css(inherited)
self.inherited = inherited
compute_css = CSSResolver()
def __call__(self, declarations_str: str) -> Dict[str, Dict[str, str]]:
"""
Convert CSS declarations to ExcelWriter style.
Parameters
----------
declarations_str : str
List of CSS declarations.
e.g. "font-weight: bold; background: blue"
Returns
-------
xlstyle : dict
A style as interpreted by ExcelWriter when found in
ExcelCell.style.
"""
# TODO: memoize?
properties = self.compute_css(declarations_str, self.inherited)
return self.build_xlstyle(properties)
def build_xlstyle(self, props: Dict[str, str]) -> Dict[str, Dict[str, str]]:
out = {
"alignment": self.build_alignment(props),
"border": self.build_border(props),
"fill": self.build_fill(props),
"font": self.build_font(props),
"number_format": self.build_number_format(props),
}
# TODO: handle cell width and height: needs support in pandas.io.excel
def remove_none(d: Dict[str, str]) -> None:
"""Remove key where value is None, through nested dicts"""
for k, v in list(d.items()):
if v is None:
del d[k]
elif isinstance(v, dict):
remove_none(v)
if not v:
del d[k]
remove_none(out)
return out
VERTICAL_MAP = {
"top": "top",
"text-top": "top",
"middle": "center",
"baseline": "bottom",
"bottom": "bottom",
"text-bottom": "bottom",
# OpenXML also has 'justify', 'distributed'
}
def build_alignment(self, props) -> Dict[str, Optional[Union[bool, str]]]:
# TODO: text-indent, padding-left -> alignment.indent
return {
"horizontal": props.get("text-align"),
"vertical": self.VERTICAL_MAP.get(props.get("vertical-align")),
"wrap_text": (
None
if props.get("white-space") is None
else props["white-space"] not in ("nowrap", "pre", "pre-line")
),
}
def build_border(self, props: Dict) -> Dict[str, Dict[str, str]]:
return {
side: {
"style": self._border_style(
props.get(f"border-{side}-style"),
props.get(f"border-{side}-width"),
),
"color": self.color_to_excel(props.get(f"border-{side}-color")),
}
for side in ["top", "right", "bottom", "left"]
}
def _border_style(self, style: Optional[str], width):
# convert styles and widths to openxml, one of:
# 'dashDot'
# 'dashDotDot'
# 'dashed'
# 'dotted'
# 'double'
# 'hair'
# 'medium'
# 'mediumDashDot'
# 'mediumDashDotDot'
# 'mediumDashed'
# 'slantDashDot'
# 'thick'
# 'thin'
if width is None and style is None:
return None
if style == "none" or style == "hidden":
return None
if width is None:
width = "2pt"
width = float(width[:-2])
if width < 1e-5:
return None
elif width < 1.3:
width_name = "thin"
elif width < 2.8:
width_name = "medium"
else:
width_name = "thick"
if style in (None, "groove", "ridge", "inset", "outset"):
# not handled
style = "solid"
if style == "double":
return "double"
if style == "solid":
return width_name
if style == "dotted":
if width_name in ("hair", "thin"):
return "dotted"
return "mediumDashDotDot"
if style == "dashed":
if width_name in ("hair", "thin"):
return "dashed"
return "mediumDashed"
def build_fill(self, props: Dict[str, str]):
# TODO: perhaps allow for special properties
# -excel-pattern-bgcolor and -excel-pattern-type
fill_color = props.get("background-color")
if fill_color not in (None, "transparent", "none"):
return {"fgColor": self.color_to_excel(fill_color), "patternType": "solid"}
BOLD_MAP = {
"bold": True,
"bolder": True,
"600": True,
"700": True,
"800": True,
"900": True,
"normal": False,
"lighter": False,
"100": False,
"200": False,
"300": False,
"400": False,
"500": False,
}
ITALIC_MAP = {"normal": False, "italic": True, "oblique": True}
def build_font(self, props) -> Dict[str, Optional[Union[bool, int, str]]]:
size = props.get("font-size")
if size is not None:
assert size.endswith("pt")
size = float(size[:-2])
font_names_tmp = re.findall(
r"""(?x)
(
"(?:[^"]|\\")+"
|
'(?:[^']|\\')+'
|
[^'",]+
)(?=,|\s*$)
""",
props.get("font-family", ""),
)
font_names = []
for name in font_names_tmp:
if name[:1] == '"':
name = name[1:-1].replace('\\"', '"')
elif name[:1] == "'":
name = name[1:-1].replace("\\'", "'")
else:
name = name.strip()
if name:
font_names.append(name)
family = None
for name in font_names:
if name == "serif":
family = 1 # roman
break
elif name == "sans-serif":
family = 2 # swiss
break
elif name == "cursive":
family = 4 # script
break
elif name == "fantasy":
family = 5 # decorative
break
decoration = props.get("text-decoration")
if decoration is not None:
decoration = decoration.split()
else:
decoration = ()
return {
"name": font_names[0] if font_names else None,
"family": family,
"size": size,
"bold": self.BOLD_MAP.get(props.get("font-weight")),
"italic": self.ITALIC_MAP.get(props.get("font-style")),
"underline": ("single" if "underline" in decoration else None),
"strike": ("line-through" in decoration) or None,
"color": self.color_to_excel(props.get("color")),
# shadow if nonzero digit before shadow color
"shadow": (
bool(re.search("^[^#(]*[1-9]", props["text-shadow"]))
if "text-shadow" in props
else None
),
# FIXME: dont leave commented-out
# 'vertAlign':,
# 'charset': ,
# 'scheme': ,
# 'outline': ,
# 'condense': ,
}
NAMED_COLORS = {
"maroon": "800000",
"brown": "A52A2A",
"red": "FF0000",
"pink": "FFC0CB",
"orange": "FFA500",
"yellow": "FFFF00",
"olive": "808000",
"green": "008000",
"purple": "800080",
"fuchsia": "FF00FF",
"lime": "00FF00",
"teal": "008080",
"aqua": "00FFFF",
"blue": "0000FF",
"navy": "000080",
"black": "000000",
"gray": "808080",
"grey": "808080",
"silver": "C0C0C0",
"white": "FFFFFF",
}
def color_to_excel(self, val: Optional[str]):
if val is None:
return None
if val.startswith("#") and len(val) == 7:
return val[1:].upper()
if val.startswith("#") and len(val) == 4:
return (val[1] * 2 + val[2] * 2 + val[3] * 2).upper()
try:
return self.NAMED_COLORS[val]
except KeyError:
warnings.warn(f"Unhandled color format: {repr(val)}", CSSWarning)
def build_number_format(self, props: Dict) -> Dict[str, Optional[str]]:
return {"format_code": props.get("number-format")}
class ExcelFormatter:
"""
Class for formatting a DataFrame to a list of ExcelCells,
Parameters
----------
df : DataFrame or Styler
na_rep: na representation
float_format : string, default None
Format string for floating point numbers
cols : sequence, optional
Columns to write
header : boolean or list of string, default True
Write out column names. If a list of string is given it is
assumed to be aliases for the column names
index : boolean, default True
output row names (index)
index_label : string or sequence, default None
Column label for index column(s) if desired. If None is given, and
`header` and `index` are True, then the index names are used. A
sequence should be given if the DataFrame uses MultiIndex.
merge_cells : boolean, default False
Format MultiIndex and Hierarchical Rows as merged cells.
inf_rep : string, default `'inf'`
representation for np.inf values (which aren't representable in Excel)
A `'-'` sign will be added in front of -inf.
style_converter : callable, optional
This translates Styler styles (CSS) into ExcelWriter styles.
Defaults to ``CSSToExcelConverter()``.
It should have signature css_declarations string -> excel style.
This is only called for body cells.
"""
max_rows = 2 ** 20
max_cols = 2 ** 14
def __init__(
self,
df,
na_rep: str = "",
float_format: Optional[str] = None,
cols: Optional[Sequence[Label]] = None,
header: Union[Sequence[Label], bool] = True,
index: bool = True,
index_label: Optional[Union[Label, Sequence[Label]]] = None,
merge_cells: bool = False,
inf_rep: str = "inf",
style_converter: Optional[Callable] = None,
):
self.rowcounter = 0
self.na_rep = na_rep
if hasattr(df, "render"):
self.styler = df
df = df.data
if style_converter is None:
style_converter = CSSToExcelConverter()
self.style_converter = style_converter
else:
self.styler = None
self.df = df
if cols is not None:
# all missing, raise
if not len(Index(cols) & df.columns):
raise KeyError("passes columns are not ALL present dataframe")
if len(Index(cols) & df.columns) != len(cols):
# Deprecated in GH#17295, enforced in 1.0.0
raise KeyError("Not all names specified in 'columns' are found")
self.df = df.reindex(columns=cols)
self.columns = self.df.columns
self.float_format = float_format
self.index = index
self.index_label = index_label
self.header = header
self.merge_cells = merge_cells
self.inf_rep = inf_rep
@property
def header_style(self):
return {
"font": {"bold": True},
"borders": {
"top": "thin",
"right": "thin",
"bottom": "thin",
"left": "thin",
},
"alignment": {"horizontal": "center", "vertical": "top"},
}
def _format_value(self, val):
if is_scalar(val) and missing.isna(val):
val = self.na_rep
elif is_float(val):
if missing.isposinf_scalar(val):
val = self.inf_rep
elif missing.isneginf_scalar(val):
val = f"-{self.inf_rep}"
elif self.float_format is not None:
val = float(self.float_format % val)
if getattr(val, "tzinfo", None) is not None:
raise ValueError(
"Excel does not support datetimes with "
"timezones. Please ensure that datetimes "
"are timezone unaware before writing to Excel."
)
return val
def _format_header_mi(self):
if self.columns.nlevels > 1:
if not self.index:
raise NotImplementedError(
"Writing to Excel with MultiIndex columns and no "
"index ('index'=False) is not yet implemented."
)
has_aliases = isinstance(self.header, (tuple, list, np.ndarray, ABCIndex))
if not (has_aliases or self.header):
return
columns = self.columns
level_strs = columns.format(
sparsify=self.merge_cells, adjoin=False, names=False
)
level_lengths = get_level_lengths(level_strs)
coloffset = 0
lnum = 0
if self.index and isinstance(self.df.index, ABCMultiIndex):
coloffset = len(self.df.index[0]) - 1
if self.merge_cells:
# Format multi-index as a merged cells.
for lnum in range(len(level_lengths)):
name = columns.names[lnum]
yield ExcelCell(lnum, coloffset, name, self.header_style)
for lnum, (spans, levels, level_codes) in enumerate(
zip(level_lengths, columns.levels, columns.codes)
):
values = levels.take(level_codes)
for i in spans:
if spans[i] > 1:
yield ExcelCell(
lnum,
coloffset + i + 1,
values[i],
self.header_style,
lnum,
coloffset + i + spans[i],
)
else:
yield ExcelCell(
lnum, coloffset + i + 1, values[i], self.header_style
)
else:
# Format in legacy format with dots to indicate levels.
for i, values in enumerate(zip(*level_strs)):
v = ".".join(map(pprint_thing, values))
yield ExcelCell(lnum, coloffset + i + 1, v, self.header_style)
self.rowcounter = lnum
def _format_header_regular(self):
has_aliases = isinstance(self.header, (tuple, list, np.ndarray, ABCIndex))
if has_aliases or self.header:
coloffset = 0
if self.index:
coloffset = 1
if isinstance(self.df.index, ABCMultiIndex):
coloffset = len(self.df.index[0])
colnames = self.columns
if has_aliases:
if len(self.header) != len(self.columns):
raise ValueError(
f"Writing {len(self.columns)} cols but got {len(self.header)} "
"aliases"
)
else:
colnames = self.header
for colindex, colname in enumerate(colnames):
yield ExcelCell(
self.rowcounter, colindex + coloffset, colname, self.header_style
)
def _format_header(self):
if isinstance(self.columns, ABCMultiIndex):
gen = self._format_header_mi()
else:
gen = self._format_header_regular()
gen2 = ()
if self.df.index.names:
row = [x if x is not None else "" for x in self.df.index.names] + [
""
] * len(self.columns)
if reduce(lambda x, y: x and y, map(lambda x: x != "", row)):
gen2 = (
ExcelCell(self.rowcounter, colindex, val, self.header_style)
for colindex, val in enumerate(row)
)
self.rowcounter += 1
return itertools.chain(gen, gen2)
def _format_body(self):
if isinstance(self.df.index, ABCMultiIndex):
return self._format_hierarchical_rows()
else:
return self._format_regular_rows()
def _format_regular_rows(self):
has_aliases = isinstance(self.header, (tuple, list, np.ndarray, ABCIndex))
if has_aliases or self.header:
self.rowcounter += 1
# output index and index_label?
if self.index:
# check aliases
# if list only take first as this is not a MultiIndex
if self.index_label and isinstance(
self.index_label, (list, tuple, np.ndarray, Index)
):
index_label = self.index_label[0]
# if string good to go
elif self.index_label and isinstance(self.index_label, str):
index_label = self.index_label
else:
index_label = self.df.index.names[0]
if isinstance(self.columns, ABCMultiIndex):
self.rowcounter += 1
if index_label and self.header is not False:
yield ExcelCell(self.rowcounter - 1, 0, index_label, self.header_style)
# write index_values
index_values = self.df.index
if isinstance(self.df.index, ABCPeriodIndex):
index_values = self.df.index.to_timestamp()
for idx, idxval in enumerate(index_values):
yield ExcelCell(self.rowcounter + idx, 0, idxval, self.header_style)
coloffset = 1
else:
coloffset = 0
for cell in self._generate_body(coloffset):
yield cell
def _format_hierarchical_rows(self):
has_aliases = isinstance(self.header, (tuple, list, np.ndarray, ABCIndex))
if has_aliases or self.header:
self.rowcounter += 1
gcolidx = 0
if self.index:
index_labels = self.df.index.names
# check for aliases
if self.index_label and isinstance(
self.index_label, (list, tuple, np.ndarray, Index)
):
index_labels = self.index_label
# MultiIndex columns require an extra row
# with index names (blank if None) for
# unambiguous round-trip, unless not merging,
# in which case the names all go on one row Issue #11328
if isinstance(self.columns, ABCMultiIndex) and self.merge_cells:
self.rowcounter += 1
# if index labels are not empty go ahead and dump
if com.any_not_none(*index_labels) and self.header is not False:
for cidx, name in enumerate(index_labels):
yield ExcelCell(self.rowcounter - 1, cidx, name, self.header_style)
if self.merge_cells:
# Format hierarchical rows as merged cells.
level_strs = self.df.index.format(
sparsify=True, adjoin=False, names=False
)
level_lengths = get_level_lengths(level_strs)
for spans, levels, level_codes in zip(
level_lengths, self.df.index.levels, self.df.index.codes
):
values = levels.take(
level_codes, allow_fill=levels._can_hold_na, fill_value=True
)
for i in spans:
if spans[i] > 1:
yield ExcelCell(
self.rowcounter + i,
gcolidx,
values[i],
self.header_style,
self.rowcounter + i + spans[i] - 1,
gcolidx,
)
else:
yield ExcelCell(
self.rowcounter + i,
gcolidx,
values[i],
self.header_style,
)
gcolidx += 1
else:
# Format hierarchical rows with non-merged values.
for indexcolvals in zip(*self.df.index):
for idx, indexcolval in enumerate(indexcolvals):
yield ExcelCell(
self.rowcounter + idx,
gcolidx,
indexcolval,
self.header_style,
)
gcolidx += 1
for cell in self._generate_body(gcolidx):
yield cell
def _generate_body(self, coloffset: int):
if self.styler is None:
styles = None
else:
styles = self.styler._compute().ctx
if not styles:
styles = None
xlstyle = None
# Write the body of the frame data series by series.
for colidx in range(len(self.columns)):
series = self.df.iloc[:, colidx]
for i, val in enumerate(series):
if styles is not None:
xlstyle = self.style_converter(";".join(styles[i, colidx]))
yield ExcelCell(self.rowcounter + i, colidx + coloffset, val, xlstyle)
def get_formatted_cells(self):
for cell in itertools.chain(self._format_header(), self._format_body()):
cell.val = self._format_value(cell.val)
yield cell
def write(
self,
writer,
sheet_name="Sheet1",
startrow=0,
startcol=0,
freeze_panes=None,
engine=None,
):
"""
writer : string or ExcelWriter object
File path or existing ExcelWriter
sheet_name : string, default 'Sheet1'
Name of sheet which will contain DataFrame
startrow :
upper left cell row to dump data frame
startcol :
upper left cell column to dump data frame
freeze_panes : tuple of integer (length 2), default None
Specifies the one-based bottommost row and rightmost column that
is to be frozen
engine : string, default None
write engine to use if writer is a path - you can also set this
via the options ``io.excel.xlsx.writer``, ``io.excel.xls.writer``,
and ``io.excel.xlsm.writer``.
"""
from pandas.io.excel import ExcelWriter
num_rows, num_cols = self.df.shape
if num_rows > self.max_rows or num_cols > self.max_cols:
raise ValueError(
f"This sheet is too large! Your sheet size is: {num_rows}, {num_cols} "
f"Max sheet size is: {self.max_rows}, {self.max_cols}"
)
if isinstance(writer, ExcelWriter):
need_save = False
else:
writer = ExcelWriter(stringify_path(writer), engine=engine)
need_save = True
formatted_cells = self.get_formatted_cells()
writer.write_cells(
formatted_cells,
sheet_name,
startrow=startrow,
startcol=startcol,
freeze_panes=freeze_panes,
)
if need_save:
writer.save()
| BugsInPy/BugsInPy/temp/projects/pandas/bug-64-fixed/pandas/pandas/io/formats/excel.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-64-buggy/pandas/pandas/io/formats/excel.py |
pandas-bug-78 | """
DataFrame
---------
An efficient 2D container for potentially mixed-type time series or other
labeled data series.
Similar to its R counterpart, data.frame, except providing automatic data
alignment and a host of useful data manipulation methods having to do with the
labeling information
"""
import collections
from collections import abc
from io import StringIO
import itertools
import sys
from textwrap import dedent
from typing import (
IO,
TYPE_CHECKING,
Any,
FrozenSet,
Hashable,
Iterable,
List,
Optional,
Sequence,
Set,
Tuple,
Type,
Union,
cast,
)
import warnings
import numpy as np
import numpy.ma as ma
from pandas._config import get_option
from pandas._libs import algos as libalgos, lib
from pandas._typing import Axes, Axis, Dtype, FilePathOrBuffer, Level, Renamer
from pandas.compat import PY37
from pandas.compat._optional import import_optional_dependency
from pandas.compat.numpy import function as nv
from pandas.util._decorators import (
Appender,
Substitution,
deprecate_kwarg,
rewrite_axis_style_signature,
)
from pandas.util._validators import (
validate_axis_style_args,
validate_bool_kwarg,
validate_percentile,
)
from pandas.core.dtypes.cast import (
cast_scalar_to_array,
coerce_to_dtypes,
find_common_type,
infer_dtype_from_scalar,
invalidate_string_dtypes,
maybe_cast_to_datetime,
maybe_convert_platform,
maybe_downcast_to_dtype,
maybe_infer_to_datetimelike,
maybe_upcast,
maybe_upcast_putmask,
)
from pandas.core.dtypes.common import (
ensure_float64,
ensure_int64,
ensure_platform_int,
infer_dtype_from_object,
is_bool_dtype,
is_dict_like,
is_dtype_equal,
is_extension_array_dtype,
is_float_dtype,
is_hashable,
is_integer,
is_integer_dtype,
is_iterator,
is_list_like,
is_named_tuple,
is_object_dtype,
is_scalar,
is_sequence,
needs_i8_conversion,
)
from pandas.core.dtypes.generic import (
ABCDataFrame,
ABCIndexClass,
ABCMultiIndex,
ABCSeries,
)
from pandas.core.dtypes.missing import isna, notna
from pandas.core import algorithms, common as com, nanops, ops
from pandas.core.accessor import CachedAccessor
from pandas.core.arrays import Categorical, ExtensionArray
from pandas.core.arrays.datetimelike import DatetimeLikeArrayMixin as DatetimeLikeArray
from pandas.core.arrays.sparse import SparseFrameAccessor
from pandas.core.generic import NDFrame, _shared_docs
from pandas.core.indexes import base as ibase
from pandas.core.indexes.api import Index, ensure_index, ensure_index_from_sequences
from pandas.core.indexes.datetimes import DatetimeIndex
from pandas.core.indexes.multi import maybe_droplevels
from pandas.core.indexes.period import PeriodIndex
from pandas.core.indexing import check_bool_indexer, convert_to_index_sliceable
from pandas.core.internals import BlockManager
from pandas.core.internals.construction import (
arrays_to_mgr,
get_names_from_index,
init_dict,
init_ndarray,
masked_rec_array_to_mgr,
reorder_arrays,
sanitize_index,
to_arrays,
)
from pandas.core.ops.missing import dispatch_fill_zeros
from pandas.core.series import Series
from pandas.io.common import get_filepath_or_buffer
from pandas.io.formats import console, format as fmt
from pandas.io.formats.printing import pprint_thing
import pandas.plotting
if TYPE_CHECKING:
from pandas.core.groupby.generic import DataFrameGroupBy
from pandas.io.formats.style import Styler
# ---------------------------------------------------------------------
# Docstring templates
_shared_doc_kwargs = dict(
axes="index, columns",
klass="DataFrame",
axes_single_arg="{0 or 'index', 1 or 'columns'}",
axis="""axis : {0 or 'index', 1 or 'columns'}, default 0
If 0 or 'index': apply function to each column.
If 1 or 'columns': apply function to each row.""",
optional_by="""
by : str or list of str
Name or list of names to sort by.
- if `axis` is 0 or `'index'` then `by` may contain index
levels and/or column labels.
- if `axis` is 1 or `'columns'` then `by` may contain column
levels and/or index labels.
.. versionchanged:: 0.23.0
Allow specifying index or column level names.""",
versionadded_to_excel="",
optional_labels="""labels : array-like, optional
New labels / index to conform the axis specified by 'axis' to.""",
optional_axis="""axis : int or str, optional
Axis to target. Can be either the axis name ('index', 'columns')
or number (0, 1).""",
)
_numeric_only_doc = """numeric_only : boolean, default None
Include only float, int, boolean data. If None, will attempt to use
everything, then use only numeric data
"""
_merge_doc = """
Merge DataFrame or named Series objects with a database-style join.
The join is done on columns or indexes. If joining columns on
columns, the DataFrame indexes *will be ignored*. Otherwise if joining indexes
on indexes or indexes on a column or columns, the index will be passed on.
Parameters
----------%s
right : DataFrame or named Series
Object to merge with.
how : {'left', 'right', 'outer', 'inner'}, default 'inner'
Type of merge to be performed.
* left: use only keys from left frame, similar to a SQL left outer join;
preserve key order.
* right: use only keys from right frame, similar to a SQL right outer join;
preserve key order.
* outer: use union of keys from both frames, similar to a SQL full outer
join; sort keys lexicographically.
* inner: use intersection of keys from both frames, similar to a SQL inner
join; preserve the order of the left keys.
on : label or list
Column or index level names to join on. These must be found in both
DataFrames. If `on` is None and not merging on indexes then this defaults
to the intersection of the columns in both DataFrames.
left_on : label or list, or array-like
Column or index level names to join on in the left DataFrame. Can also
be an array or list of arrays of the length of the left DataFrame.
These arrays are treated as if they are columns.
right_on : label or list, or array-like
Column or index level names to join on in the right DataFrame. Can also
be an array or list of arrays of the length of the right DataFrame.
These arrays are treated as if they are columns.
left_index : bool, default False
Use the index from the left DataFrame as the join key(s). If it is a
MultiIndex, the number of keys in the other DataFrame (either the index
or a number of columns) must match the number of levels.
right_index : bool, default False
Use the index from the right DataFrame as the join key. Same caveats as
left_index.
sort : bool, default False
Sort the join keys lexicographically in the result DataFrame. If False,
the order of the join keys depends on the join type (how keyword).
suffixes : tuple of (str, str), default ('_x', '_y')
Suffix to apply to overlapping column names in the left and right
side, respectively. To raise an exception on overlapping columns use
(False, False).
copy : bool, default True
If False, avoid copy if possible.
indicator : bool or str, default False
If True, adds a column to output DataFrame called "_merge" with
information on the source of each row.
If string, column with information on source of each row will be added to
output DataFrame, and column will be named value of string.
Information column is Categorical-type and takes on a value of "left_only"
for observations whose merge key only appears in 'left' DataFrame,
"right_only" for observations whose merge key only appears in 'right'
DataFrame, and "both" if the observation's merge key is found in both.
validate : str, optional
If specified, checks if merge is of specified type.
* "one_to_one" or "1:1": check if merge keys are unique in both
left and right datasets.
* "one_to_many" or "1:m": check if merge keys are unique in left
dataset.
* "many_to_one" or "m:1": check if merge keys are unique in right
dataset.
* "many_to_many" or "m:m": allowed, but does not result in checks.
.. versionadded:: 0.21.0
Returns
-------
DataFrame
A DataFrame of the two merged objects.
See Also
--------
merge_ordered : Merge with optional filling/interpolation.
merge_asof : Merge on nearest keys.
DataFrame.join : Similar method using indices.
Notes
-----
Support for specifying index levels as the `on`, `left_on`, and
`right_on` parameters was added in version 0.23.0
Support for merging named Series objects was added in version 0.24.0
Examples
--------
>>> df1 = pd.DataFrame({'lkey': ['foo', 'bar', 'baz', 'foo'],
... 'value': [1, 2, 3, 5]})
>>> df2 = pd.DataFrame({'rkey': ['foo', 'bar', 'baz', 'foo'],
... 'value': [5, 6, 7, 8]})
>>> df1
lkey value
0 foo 1
1 bar 2
2 baz 3
3 foo 5
>>> df2
rkey value
0 foo 5
1 bar 6
2 baz 7
3 foo 8
Merge df1 and df2 on the lkey and rkey columns. The value columns have
the default suffixes, _x and _y, appended.
>>> df1.merge(df2, left_on='lkey', right_on='rkey')
lkey value_x rkey value_y
0 foo 1 foo 5
1 foo 1 foo 8
2 foo 5 foo 5
3 foo 5 foo 8
4 bar 2 bar 6
5 baz 3 baz 7
Merge DataFrames df1 and df2 with specified left and right suffixes
appended to any overlapping columns.
>>> df1.merge(df2, left_on='lkey', right_on='rkey',
... suffixes=('_left', '_right'))
lkey value_left rkey value_right
0 foo 1 foo 5
1 foo 1 foo 8
2 foo 5 foo 5
3 foo 5 foo 8
4 bar 2 bar 6
5 baz 3 baz 7
Merge DataFrames df1 and df2, but raise an exception if the DataFrames have
any overlapping columns.
>>> df1.merge(df2, left_on='lkey', right_on='rkey', suffixes=(False, False))
Traceback (most recent call last):
...
ValueError: columns overlap but no suffix specified:
Index(['value'], dtype='object')
"""
# -----------------------------------------------------------------------
# DataFrame class
class DataFrame(NDFrame):
"""
Two-dimensional, size-mutable, potentially heterogeneous tabular data.
Data structure also contains labeled axes (rows and columns).
Arithmetic operations align on both row and column labels. Can be
thought of as a dict-like container for Series objects. The primary
pandas data structure.
Parameters
----------
data : ndarray (structured or homogeneous), Iterable, dict, or DataFrame
Dict can contain Series, arrays, constants, or list-like objects.
.. versionchanged:: 0.23.0
If data is a dict, column order follows insertion-order for
Python 3.6 and later.
.. versionchanged:: 0.25.0
If data is a list of dicts, column order follows insertion-order
for Python 3.6 and later.
index : Index or array-like
Index to use for resulting frame. Will default to RangeIndex if
no indexing information part of input data and no index provided.
columns : Index or array-like
Column labels to use for resulting frame. Will default to
RangeIndex (0, 1, 2, ..., n) if no column labels are provided.
dtype : dtype, default None
Data type to force. Only a single dtype is allowed. If None, infer.
copy : bool, default False
Copy data from inputs. Only affects DataFrame / 2d ndarray input.
See Also
--------
DataFrame.from_records : Constructor from tuples, also record arrays.
DataFrame.from_dict : From dicts of Series, arrays, or dicts.
read_csv
read_table
read_clipboard
Examples
--------
Constructing DataFrame from a dictionary.
>>> d = {'col1': [1, 2], 'col2': [3, 4]}
>>> df = pd.DataFrame(data=d)
>>> df
col1 col2
0 1 3
1 2 4
Notice that the inferred dtype is int64.
>>> df.dtypes
col1 int64
col2 int64
dtype: object
To enforce a single dtype:
>>> df = pd.DataFrame(data=d, dtype=np.int8)
>>> df.dtypes
col1 int8
col2 int8
dtype: object
Constructing DataFrame from numpy ndarray:
>>> df2 = pd.DataFrame(np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]]),
... columns=['a', 'b', 'c'])
>>> df2
a b c
0 1 2 3
1 4 5 6
2 7 8 9
"""
_typ = "dataframe"
@property
def _constructor(self) -> Type["DataFrame"]:
return DataFrame
_constructor_sliced: Type[Series] = Series
_deprecations: FrozenSet[str] = NDFrame._deprecations | frozenset([])
_accessors: Set[str] = {"sparse"}
@property
def _constructor_expanddim(self):
raise NotImplementedError("Not supported for DataFrames!")
# ----------------------------------------------------------------------
# Constructors
def __init__(
self,
data=None,
index: Optional[Axes] = None,
columns: Optional[Axes] = None,
dtype: Optional[Dtype] = None,
copy: bool = False,
):
if data is None:
data = {}
if dtype is not None:
dtype = self._validate_dtype(dtype)
if isinstance(data, DataFrame):
data = data._data
if isinstance(data, BlockManager):
mgr = self._init_mgr(
data, axes=dict(index=index, columns=columns), dtype=dtype, copy=copy
)
elif isinstance(data, dict):
mgr = init_dict(data, index, columns, dtype=dtype)
elif isinstance(data, ma.MaskedArray):
import numpy.ma.mrecords as mrecords
# masked recarray
if isinstance(data, mrecords.MaskedRecords):
mgr = masked_rec_array_to_mgr(data, index, columns, dtype, copy)
# a masked array
else:
mask = ma.getmaskarray(data)
if mask.any():
data, fill_value = maybe_upcast(data, copy=True)
data.soften_mask() # set hardmask False if it was True
data[mask] = fill_value
else:
data = data.copy()
mgr = init_ndarray(data, index, columns, dtype=dtype, copy=copy)
elif isinstance(data, (np.ndarray, Series, Index)):
if data.dtype.names:
data_columns = list(data.dtype.names)
data = {k: data[k] for k in data_columns}
if columns is None:
columns = data_columns
mgr = init_dict(data, index, columns, dtype=dtype)
elif getattr(data, "name", None) is not None:
mgr = init_dict({data.name: data}, index, columns, dtype=dtype)
else:
mgr = init_ndarray(data, index, columns, dtype=dtype, copy=copy)
# For data is list-like, or Iterable (will consume into list)
elif isinstance(data, abc.Iterable) and not isinstance(data, (str, bytes)):
if not isinstance(data, (abc.Sequence, ExtensionArray)):
data = list(data)
if len(data) > 0:
if is_list_like(data[0]) and getattr(data[0], "ndim", 1) == 1:
if is_named_tuple(data[0]) and columns is None:
columns = data[0]._fields
arrays, columns = to_arrays(data, columns, dtype=dtype)
columns = ensure_index(columns)
# set the index
if index is None:
if isinstance(data[0], Series):
index = get_names_from_index(data)
elif isinstance(data[0], Categorical):
index = ibase.default_index(len(data[0]))
else:
index = ibase.default_index(len(data))
mgr = arrays_to_mgr(arrays, columns, index, columns, dtype=dtype)
else:
mgr = init_ndarray(data, index, columns, dtype=dtype, copy=copy)
else:
mgr = init_dict({}, index, columns, dtype=dtype)
else:
try:
arr = np.array(data, dtype=dtype, copy=copy)
except (ValueError, TypeError) as err:
exc = TypeError(
"DataFrame constructor called with "
f"incompatible data and dtype: {err}"
)
raise exc from err
if arr.ndim == 0 and index is not None and columns is not None:
values = cast_scalar_to_array(
(len(index), len(columns)), data, dtype=dtype
)
mgr = init_ndarray(
values, index, columns, dtype=values.dtype, copy=False
)
else:
raise ValueError("DataFrame constructor not properly called!")
NDFrame.__init__(self, mgr, fastpath=True)
# ----------------------------------------------------------------------
@property
def axes(self) -> List[Index]:
"""
Return a list representing the axes of the DataFrame.
It has the row axis labels and column axis labels as the only members.
They are returned in that order.
Examples
--------
>>> df = pd.DataFrame({'col1': [1, 2], 'col2': [3, 4]})
>>> df.axes
[RangeIndex(start=0, stop=2, step=1), Index(['col1', 'col2'],
dtype='object')]
"""
return [self.index, self.columns]
@property
def shape(self) -> Tuple[int, int]:
"""
Return a tuple representing the dimensionality of the DataFrame.
See Also
--------
ndarray.shape
Examples
--------
>>> df = pd.DataFrame({'col1': [1, 2], 'col2': [3, 4]})
>>> df.shape
(2, 2)
>>> df = pd.DataFrame({'col1': [1, 2], 'col2': [3, 4],
... 'col3': [5, 6]})
>>> df.shape
(2, 3)
"""
return len(self.index), len(self.columns)
@property
def _is_homogeneous_type(self) -> bool:
"""
Whether all the columns in a DataFrame have the same type.
Returns
-------
bool
See Also
--------
Index._is_homogeneous_type : Whether the object has a single
dtype.
MultiIndex._is_homogeneous_type : Whether all the levels of a
MultiIndex have the same dtype.
Examples
--------
>>> DataFrame({"A": [1, 2], "B": [3, 4]})._is_homogeneous_type
True
>>> DataFrame({"A": [1, 2], "B": [3.0, 4.0]})._is_homogeneous_type
False
Items with the same type but different sizes are considered
different types.
>>> DataFrame({
... "A": np.array([1, 2], dtype=np.int32),
... "B": np.array([1, 2], dtype=np.int64)})._is_homogeneous_type
False
"""
if self._data.any_extension_types:
return len({block.dtype for block in self._data.blocks}) == 1
else:
return not self._data.is_mixed_type
# ----------------------------------------------------------------------
# Rendering Methods
def _repr_fits_vertical_(self) -> bool:
"""
Check length against max_rows.
"""
max_rows = get_option("display.max_rows")
return len(self) <= max_rows
def _repr_fits_horizontal_(self, ignore_width: bool = False) -> bool:
"""
Check if full repr fits in horizontal boundaries imposed by the display
options width and max_columns.
In case off non-interactive session, no boundaries apply.
`ignore_width` is here so ipnb+HTML output can behave the way
users expect. display.max_columns remains in effect.
GH3541, GH3573
"""
width, height = console.get_console_size()
max_columns = get_option("display.max_columns")
nb_columns = len(self.columns)
# exceed max columns
if (max_columns and nb_columns > max_columns) or (
(not ignore_width) and width and nb_columns > (width // 2)
):
return False
# used by repr_html under IPython notebook or scripts ignore terminal
# dims
if ignore_width or not console.in_interactive_session():
return True
if get_option("display.width") is not None or console.in_ipython_frontend():
# check at least the column row for excessive width
max_rows = 1
else:
max_rows = get_option("display.max_rows")
# when auto-detecting, so width=None and not in ipython front end
# check whether repr fits horizontal by actually checking
# the width of the rendered repr
buf = StringIO()
# only care about the stuff we'll actually print out
# and to_string on entire frame may be expensive
d = self
if not (max_rows is None): # unlimited rows
# min of two, where one may be None
d = d.iloc[: min(max_rows, len(d))]
else:
return True
d.to_string(buf=buf)
value = buf.getvalue()
repr_width = max(len(l) for l in value.split("\n"))
return repr_width < width
def _info_repr(self) -> bool:
"""
True if the repr should show the info view.
"""
info_repr_option = get_option("display.large_repr") == "info"
return info_repr_option and not (
self._repr_fits_horizontal_() and self._repr_fits_vertical_()
)
def __repr__(self) -> str:
"""
Return a string representation for a particular DataFrame.
"""
buf = StringIO("")
if self._info_repr():
self.info(buf=buf)
return buf.getvalue()
max_rows = get_option("display.max_rows")
min_rows = get_option("display.min_rows")
max_cols = get_option("display.max_columns")
max_colwidth = get_option("display.max_colwidth")
show_dimensions = get_option("display.show_dimensions")
if get_option("display.expand_frame_repr"):
width, _ = console.get_console_size()
else:
width = None
self.to_string(
buf=buf,
max_rows=max_rows,
min_rows=min_rows,
max_cols=max_cols,
line_width=width,
max_colwidth=max_colwidth,
show_dimensions=show_dimensions,
)
return buf.getvalue()
def _repr_html_(self) -> Optional[str]:
"""
Return a html representation for a particular DataFrame.
Mainly for IPython notebook.
"""
if self._info_repr():
buf = StringIO("")
self.info(buf=buf)
# need to escape the <class>, should be the first line.
val = buf.getvalue().replace("<", r"<", 1)
val = val.replace(">", r">", 1)
return "<pre>" + val + "</pre>"
if get_option("display.notebook_repr_html"):
max_rows = get_option("display.max_rows")
min_rows = get_option("display.min_rows")
max_cols = get_option("display.max_columns")
show_dimensions = get_option("display.show_dimensions")
formatter = fmt.DataFrameFormatter(
self,
columns=None,
col_space=None,
na_rep="NaN",
formatters=None,
float_format=None,
sparsify=None,
justify=None,
index_names=True,
header=True,
index=True,
bold_rows=True,
escape=True,
max_rows=max_rows,
min_rows=min_rows,
max_cols=max_cols,
show_dimensions=show_dimensions,
decimal=".",
table_id=None,
render_links=False,
)
return formatter.to_html(notebook=True)
else:
return None
@Substitution(
header_type="bool or sequence",
header="Write out the column names. If a list of strings "
"is given, it is assumed to be aliases for the "
"column names",
col_space_type="int",
col_space="The minimum width of each column",
)
@Substitution(shared_params=fmt.common_docstring, returns=fmt.return_docstring)
def to_string(
self,
buf: Optional[FilePathOrBuffer[str]] = None,
columns: Optional[Sequence[str]] = None,
col_space: Optional[int] = None,
header: Union[bool, Sequence[str]] = True,
index: bool = True,
na_rep: str = "NaN",
formatters: Optional[fmt.formatters_type] = None,
float_format: Optional[fmt.float_format_type] = None,
sparsify: Optional[bool] = None,
index_names: bool = True,
justify: Optional[str] = None,
max_rows: Optional[int] = None,
min_rows: Optional[int] = None,
max_cols: Optional[int] = None,
show_dimensions: bool = False,
decimal: str = ".",
line_width: Optional[int] = None,
max_colwidth: Optional[int] = None,
encoding: Optional[str] = None,
) -> Optional[str]:
"""
Render a DataFrame to a console-friendly tabular output.
%(shared_params)s
line_width : int, optional
Width to wrap a line in characters.
max_colwidth : int, optional
Max width to truncate each column in characters. By default, no limit.
.. versionadded:: 1.0.0
encoding : str, default "utf-8"
Set character encoding.
.. versionadded:: 1.0
%(returns)s
See Also
--------
to_html : Convert DataFrame to HTML.
Examples
--------
>>> d = {'col1': [1, 2, 3], 'col2': [4, 5, 6]}
>>> df = pd.DataFrame(d)
>>> print(df.to_string())
col1 col2
0 1 4
1 2 5
2 3 6
"""
from pandas import option_context
with option_context("display.max_colwidth", max_colwidth):
formatter = fmt.DataFrameFormatter(
self,
columns=columns,
col_space=col_space,
na_rep=na_rep,
formatters=formatters,
float_format=float_format,
sparsify=sparsify,
justify=justify,
index_names=index_names,
header=header,
index=index,
min_rows=min_rows,
max_rows=max_rows,
max_cols=max_cols,
show_dimensions=show_dimensions,
decimal=decimal,
line_width=line_width,
)
return formatter.to_string(buf=buf, encoding=encoding)
# ----------------------------------------------------------------------
@property
def style(self) -> "Styler":
"""
Returns a Styler object.
Contains methods for building a styled HTML representation of the DataFrame.
a styled HTML representation fo the DataFrame.
See Also
--------
io.formats.style.Styler
"""
from pandas.io.formats.style import Styler
return Styler(self)
_shared_docs[
"items"
] = r"""
Iterate over (column name, Series) pairs.
Iterates over the DataFrame columns, returning a tuple with
the column name and the content as a Series.
Yields
------
label : object
The column names for the DataFrame being iterated over.
content : Series
The column entries belonging to each label, as a Series.
See Also
--------
DataFrame.iterrows : Iterate over DataFrame rows as
(index, Series) pairs.
DataFrame.itertuples : Iterate over DataFrame rows as namedtuples
of the values.
Examples
--------
>>> df = pd.DataFrame({'species': ['bear', 'bear', 'marsupial'],
... 'population': [1864, 22000, 80000]},
... index=['panda', 'polar', 'koala'])
>>> df
species population
panda bear 1864
polar bear 22000
koala marsupial 80000
>>> for label, content in df.items():
... print('label:', label)
... print('content:', content, sep='\n')
...
label: species
content:
panda bear
polar bear
koala marsupial
Name: species, dtype: object
label: population
content:
panda 1864
polar 22000
koala 80000
Name: population, dtype: int64
"""
@Appender(_shared_docs["items"])
def items(self) -> Iterable[Tuple[Optional[Hashable], Series]]:
if self.columns.is_unique and hasattr(self, "_item_cache"):
for k in self.columns:
yield k, self._get_item_cache(k)
else:
for i, k in enumerate(self.columns):
yield k, self._ixs(i, axis=1)
@Appender(_shared_docs["items"])
def iteritems(self) -> Iterable[Tuple[Optional[Hashable], Series]]:
yield from self.items()
def iterrows(self) -> Iterable[Tuple[Optional[Hashable], Series]]:
"""
Iterate over DataFrame rows as (index, Series) pairs.
Yields
------
index : label or tuple of label
The index of the row. A tuple for a `MultiIndex`.
data : Series
The data of the row as a Series.
it : generator
A generator that iterates over the rows of the frame.
See Also
--------
DataFrame.itertuples : Iterate over DataFrame rows as namedtuples of the values.
DataFrame.items : Iterate over (column name, Series) pairs.
Notes
-----
1. Because ``iterrows`` returns a Series for each row,
it does **not** preserve dtypes across the rows (dtypes are
preserved across columns for DataFrames). For example,
>>> df = pd.DataFrame([[1, 1.5]], columns=['int', 'float'])
>>> row = next(df.iterrows())[1]
>>> row
int 1.0
float 1.5
Name: 0, dtype: float64
>>> print(row['int'].dtype)
float64
>>> print(df['int'].dtype)
int64
To preserve dtypes while iterating over the rows, it is better
to use :meth:`itertuples` which returns namedtuples of the values
and which is generally faster than ``iterrows``.
2. You should **never modify** something you are iterating over.
This is not guaranteed to work in all cases. Depending on the
data types, the iterator returns a copy and not a view, and writing
to it will have no effect.
"""
columns = self.columns
klass = self._constructor_sliced
for k, v in zip(self.index, self.values):
s = klass(v, index=columns, name=k)
yield k, s
def itertuples(self, index=True, name="Pandas"):
"""
Iterate over DataFrame rows as namedtuples.
Parameters
----------
index : bool, default True
If True, return the index as the first element of the tuple.
name : str or None, default "Pandas"
The name of the returned namedtuples or None to return regular
tuples.
Returns
-------
iterator
An object to iterate over namedtuples for each row in the
DataFrame with the first field possibly being the index and
following fields being the column values.
See Also
--------
DataFrame.iterrows : Iterate over DataFrame rows as (index, Series)
pairs.
DataFrame.items : Iterate over (column name, Series) pairs.
Notes
-----
The column names will be renamed to positional names if they are
invalid Python identifiers, repeated, or start with an underscore.
On python versions < 3.7 regular tuples are returned for DataFrames
with a large number of columns (>254).
Examples
--------
>>> df = pd.DataFrame({'num_legs': [4, 2], 'num_wings': [0, 2]},
... index=['dog', 'hawk'])
>>> df
num_legs num_wings
dog 4 0
hawk 2 2
>>> for row in df.itertuples():
... print(row)
...
Pandas(Index='dog', num_legs=4, num_wings=0)
Pandas(Index='hawk', num_legs=2, num_wings=2)
By setting the `index` parameter to False we can remove the index
as the first element of the tuple:
>>> for row in df.itertuples(index=False):
... print(row)
...
Pandas(num_legs=4, num_wings=0)
Pandas(num_legs=2, num_wings=2)
With the `name` parameter set we set a custom name for the yielded
namedtuples:
>>> for row in df.itertuples(name='Animal'):
... print(row)
...
Animal(Index='dog', num_legs=4, num_wings=0)
Animal(Index='hawk', num_legs=2, num_wings=2)
"""
arrays = []
fields = list(self.columns)
if index:
arrays.append(self.index)
fields.insert(0, "Index")
# use integer indexing because of possible duplicate column names
arrays.extend(self.iloc[:, k] for k in range(len(self.columns)))
# Python versions before 3.7 support at most 255 arguments to constructors
can_return_named_tuples = PY37 or len(self.columns) + index < 255
if name is not None and can_return_named_tuples:
itertuple = collections.namedtuple(name, fields, rename=True)
return map(itertuple._make, zip(*arrays))
# fallback to regular tuples
return zip(*arrays)
def __len__(self) -> int:
"""
Returns length of info axis, but here we use the index.
"""
return len(self.index)
def dot(self, other):
"""
Compute the matrix multiplication between the DataFrame and other.
This method computes the matrix product between the DataFrame and the
values of an other Series, DataFrame or a numpy array.
It can also be called using ``self @ other`` in Python >= 3.5.
Parameters
----------
other : Series, DataFrame or array-like
The other object to compute the matrix product with.
Returns
-------
Series or DataFrame
If other is a Series, return the matrix product between self and
other as a Serie. If other is a DataFrame or a numpy.array, return
the matrix product of self and other in a DataFrame of a np.array.
See Also
--------
Series.dot: Similar method for Series.
Notes
-----
The dimensions of DataFrame and other must be compatible in order to
compute the matrix multiplication. In addition, the column names of
DataFrame and the index of other must contain the same values, as they
will be aligned prior to the multiplication.
The dot method for Series computes the inner product, instead of the
matrix product here.
Examples
--------
Here we multiply a DataFrame with a Series.
>>> df = pd.DataFrame([[0, 1, -2, -1], [1, 1, 1, 1]])
>>> s = pd.Series([1, 1, 2, 1])
>>> df.dot(s)
0 -4
1 5
dtype: int64
Here we multiply a DataFrame with another DataFrame.
>>> other = pd.DataFrame([[0, 1], [1, 2], [-1, -1], [2, 0]])
>>> df.dot(other)
0 1
0 1 4
1 2 2
Note that the dot method give the same result as @
>>> df @ other
0 1
0 1 4
1 2 2
The dot method works also if other is an np.array.
>>> arr = np.array([[0, 1], [1, 2], [-1, -1], [2, 0]])
>>> df.dot(arr)
0 1
0 1 4
1 2 2
Note how shuffling of the objects does not change the result.
>>> s2 = s.reindex([1, 0, 2, 3])
>>> df.dot(s2)
0 -4
1 5
dtype: int64
"""
if isinstance(other, (Series, DataFrame)):
common = self.columns.union(other.index)
if len(common) > len(self.columns) or len(common) > len(other.index):
raise ValueError("matrices are not aligned")
left = self.reindex(columns=common, copy=False)
right = other.reindex(index=common, copy=False)
lvals = left.values
rvals = right.values
else:
left = self
lvals = self.values
rvals = np.asarray(other)
if lvals.shape[1] != rvals.shape[0]:
raise ValueError(
f"Dot product shape mismatch, {lvals.shape} vs {rvals.shape}"
)
if isinstance(other, DataFrame):
return self._constructor(
np.dot(lvals, rvals), index=left.index, columns=other.columns
)
elif isinstance(other, Series):
return Series(np.dot(lvals, rvals), index=left.index)
elif isinstance(rvals, (np.ndarray, Index)):
result = np.dot(lvals, rvals)
if result.ndim == 2:
return self._constructor(result, index=left.index)
else:
return Series(result, index=left.index)
else: # pragma: no cover
raise TypeError(f"unsupported type: {type(other)}")
def __matmul__(self, other):
"""
Matrix multiplication using binary `@` operator in Python>=3.5.
"""
return self.dot(other)
def __rmatmul__(self, other):
"""
Matrix multiplication using binary `@` operator in Python>=3.5.
"""
return self.T.dot(np.transpose(other)).T
# ----------------------------------------------------------------------
# IO methods (to / from other formats)
@classmethod
def from_dict(cls, data, orient="columns", dtype=None, columns=None) -> "DataFrame":
"""
Construct DataFrame from dict of array-like or dicts.
Creates DataFrame object from dictionary by columns or by index
allowing dtype specification.
Parameters
----------
data : dict
Of the form {field : array-like} or {field : dict}.
orient : {'columns', 'index'}, default 'columns'
The "orientation" of the data. If the keys of the passed dict
should be the columns of the resulting DataFrame, pass 'columns'
(default). Otherwise if the keys should be rows, pass 'index'.
dtype : dtype, default None
Data type to force, otherwise infer.
columns : list, default None
Column labels to use when ``orient='index'``. Raises a ValueError
if used with ``orient='columns'``.
.. versionadded:: 0.23.0
Returns
-------
DataFrame
See Also
--------
DataFrame.from_records : DataFrame from ndarray (structured
dtype), list of tuples, dict, or DataFrame.
DataFrame : DataFrame object creation using constructor.
Examples
--------
By default the keys of the dict become the DataFrame columns:
>>> data = {'col_1': [3, 2, 1, 0], 'col_2': ['a', 'b', 'c', 'd']}
>>> pd.DataFrame.from_dict(data)
col_1 col_2
0 3 a
1 2 b
2 1 c
3 0 d
Specify ``orient='index'`` to create the DataFrame using dictionary
keys as rows:
>>> data = {'row_1': [3, 2, 1, 0], 'row_2': ['a', 'b', 'c', 'd']}
>>> pd.DataFrame.from_dict(data, orient='index')
0 1 2 3
row_1 3 2 1 0
row_2 a b c d
When using the 'index' orientation, the column names can be
specified manually:
>>> pd.DataFrame.from_dict(data, orient='index',
... columns=['A', 'B', 'C', 'D'])
A B C D
row_1 3 2 1 0
row_2 a b c d
"""
index = None
orient = orient.lower()
if orient == "index":
if len(data) > 0:
# TODO speed up Series case
if isinstance(list(data.values())[0], (Series, dict)):
data = _from_nested_dict(data)
else:
data, index = list(data.values()), list(data.keys())
elif orient == "columns":
if columns is not None:
raise ValueError("cannot use columns parameter with orient='columns'")
else: # pragma: no cover
raise ValueError("only recognize index or columns for orient")
return cls(data, index=index, columns=columns, dtype=dtype)
def to_numpy(self, dtype=None, copy=False) -> np.ndarray:
"""
Convert the DataFrame to a NumPy array.
.. versionadded:: 0.24.0
By default, the dtype of the returned array will be the common NumPy
dtype of all types in the DataFrame. For example, if the dtypes are
``float16`` and ``float32``, the results dtype will be ``float32``.
This may require copying data and coercing values, which may be
expensive.
Parameters
----------
dtype : str or numpy.dtype, optional
The dtype to pass to :meth:`numpy.asarray`.
copy : bool, default False
Whether to ensure that the returned value is a not a view on
another array. Note that ``copy=False`` does not *ensure* that
``to_numpy()`` is no-copy. Rather, ``copy=True`` ensure that
a copy is made, even if not strictly necessary.
Returns
-------
numpy.ndarray
See Also
--------
Series.to_numpy : Similar method for Series.
Examples
--------
>>> pd.DataFrame({"A": [1, 2], "B": [3, 4]}).to_numpy()
array([[1, 3],
[2, 4]])
With heterogeneous data, the lowest common type will have to
be used.
>>> df = pd.DataFrame({"A": [1, 2], "B": [3.0, 4.5]})
>>> df.to_numpy()
array([[1. , 3. ],
[2. , 4.5]])
For a mix of numeric and non-numeric types, the output array will
have object dtype.
>>> df['C'] = pd.date_range('2000', periods=2)
>>> df.to_numpy()
array([[1, 3.0, Timestamp('2000-01-01 00:00:00')],
[2, 4.5, Timestamp('2000-01-02 00:00:00')]], dtype=object)
"""
result = np.array(self.values, dtype=dtype, copy=copy)
return result
def to_dict(self, orient="dict", into=dict):
"""
Convert the DataFrame to a dictionary.
The type of the key-value pairs can be customized with the parameters
(see below).
Parameters
----------
orient : str {'dict', 'list', 'series', 'split', 'records', 'index'}
Determines the type of the values of the dictionary.
- 'dict' (default) : dict like {column -> {index -> value}}
- 'list' : dict like {column -> [values]}
- 'series' : dict like {column -> Series(values)}
- 'split' : dict like
{'index' -> [index], 'columns' -> [columns], 'data' -> [values]}
- 'records' : list like
[{column -> value}, ... , {column -> value}]
- 'index' : dict like {index -> {column -> value}}
Abbreviations are allowed. `s` indicates `series` and `sp`
indicates `split`.
into : class, default dict
The collections.abc.Mapping subclass used for all Mappings
in the return value. Can be the actual class or an empty
instance of the mapping type you want. If you want a
collections.defaultdict, you must pass it initialized.
.. versionadded:: 0.21.0
Returns
-------
dict, list or collections.abc.Mapping
Return a collections.abc.Mapping object representing the DataFrame.
The resulting transformation depends on the `orient` parameter.
See Also
--------
DataFrame.from_dict: Create a DataFrame from a dictionary.
DataFrame.to_json: Convert a DataFrame to JSON format.
Examples
--------
>>> df = pd.DataFrame({'col1': [1, 2],
... 'col2': [0.5, 0.75]},
... index=['row1', 'row2'])
>>> df
col1 col2
row1 1 0.50
row2 2 0.75
>>> df.to_dict()
{'col1': {'row1': 1, 'row2': 2}, 'col2': {'row1': 0.5, 'row2': 0.75}}
You can specify the return orientation.
>>> df.to_dict('series')
{'col1': row1 1
row2 2
Name: col1, dtype: int64,
'col2': row1 0.50
row2 0.75
Name: col2, dtype: float64}
>>> df.to_dict('split')
{'index': ['row1', 'row2'], 'columns': ['col1', 'col2'],
'data': [[1, 0.5], [2, 0.75]]}
>>> df.to_dict('records')
[{'col1': 1, 'col2': 0.5}, {'col1': 2, 'col2': 0.75}]
>>> df.to_dict('index')
{'row1': {'col1': 1, 'col2': 0.5}, 'row2': {'col1': 2, 'col2': 0.75}}
You can also specify the mapping type.
>>> from collections import OrderedDict, defaultdict
>>> df.to_dict(into=OrderedDict)
OrderedDict([('col1', OrderedDict([('row1', 1), ('row2', 2)])),
('col2', OrderedDict([('row1', 0.5), ('row2', 0.75)]))])
If you want a `defaultdict`, you need to initialize it:
>>> dd = defaultdict(list)
>>> df.to_dict('records', into=dd)
[defaultdict(<class 'list'>, {'col1': 1, 'col2': 0.5}),
defaultdict(<class 'list'>, {'col1': 2, 'col2': 0.75})]
"""
if not self.columns.is_unique:
warnings.warn(
"DataFrame columns are not unique, some columns will be omitted.",
UserWarning,
stacklevel=2,
)
# GH16122
into_c = com.standardize_mapping(into)
if orient.lower().startswith("d"):
return into_c((k, v.to_dict(into)) for k, v in self.items())
elif orient.lower().startswith("l"):
return into_c((k, v.tolist()) for k, v in self.items())
elif orient.lower().startswith("sp"):
return into_c(
(
("index", self.index.tolist()),
("columns", self.columns.tolist()),
(
"data",
[
list(map(com.maybe_box_datetimelike, t))
for t in self.itertuples(index=False, name=None)
],
),
)
)
elif orient.lower().startswith("s"):
return into_c((k, com.maybe_box_datetimelike(v)) for k, v in self.items())
elif orient.lower().startswith("r"):
columns = self.columns.tolist()
rows = (
dict(zip(columns, row))
for row in self.itertuples(index=False, name=None)
)
return [
into_c((k, com.maybe_box_datetimelike(v)) for k, v in row.items())
for row in rows
]
elif orient.lower().startswith("i"):
if not self.index.is_unique:
raise ValueError("DataFrame index must be unique for orient='index'.")
return into_c(
(t[0], dict(zip(self.columns, t[1:])))
for t in self.itertuples(name=None)
)
else:
raise ValueError(f"orient '{orient}' not understood")
def to_gbq(
self,
destination_table,
project_id=None,
chunksize=None,
reauth=False,
if_exists="fail",
auth_local_webserver=False,
table_schema=None,
location=None,
progress_bar=True,
credentials=None,
) -> None:
"""
Write a DataFrame to a Google BigQuery table.
This function requires the `pandas-gbq package
<https://pandas-gbq.readthedocs.io>`__.
See the `How to authenticate with Google BigQuery
<https://pandas-gbq.readthedocs.io/en/latest/howto/authentication.html>`__
guide for authentication instructions.
Parameters
----------
destination_table : str
Name of table to be written, in the form ``dataset.tablename``.
project_id : str, optional
Google BigQuery Account project ID. Optional when available from
the environment.
chunksize : int, optional
Number of rows to be inserted in each chunk from the dataframe.
Set to ``None`` to load the whole dataframe at once.
reauth : bool, default False
Force Google BigQuery to re-authenticate the user. This is useful
if multiple accounts are used.
if_exists : str, default 'fail'
Behavior when the destination table exists. Value can be one of:
``'fail'``
If table exists raise pandas_gbq.gbq.TableCreationError.
``'replace'``
If table exists, drop it, recreate it, and insert data.
``'append'``
If table exists, insert data. Create if does not exist.
auth_local_webserver : bool, default False
Use the `local webserver flow`_ instead of the `console flow`_
when getting user credentials.
.. _local webserver flow:
http://google-auth-oauthlib.readthedocs.io/en/latest/reference/google_auth_oauthlib.flow.html#google_auth_oauthlib.flow.InstalledAppFlow.run_local_server
.. _console flow:
http://google-auth-oauthlib.readthedocs.io/en/latest/reference/google_auth_oauthlib.flow.html#google_auth_oauthlib.flow.InstalledAppFlow.run_console
*New in version 0.2.0 of pandas-gbq*.
table_schema : list of dicts, optional
List of BigQuery table fields to which according DataFrame
columns conform to, e.g. ``[{'name': 'col1', 'type':
'STRING'},...]``. If schema is not provided, it will be
generated according to dtypes of DataFrame columns. See
BigQuery API documentation on available names of a field.
*New in version 0.3.1 of pandas-gbq*.
location : str, optional
Location where the load job should run. See the `BigQuery locations
documentation
<https://cloud.google.com/bigquery/docs/dataset-locations>`__ for a
list of available locations. The location must match that of the
target dataset.
*New in version 0.5.0 of pandas-gbq*.
progress_bar : bool, default True
Use the library `tqdm` to show the progress bar for the upload,
chunk by chunk.
*New in version 0.5.0 of pandas-gbq*.
credentials : google.auth.credentials.Credentials, optional
Credentials for accessing Google APIs. Use this parameter to
override default credentials, such as to use Compute Engine
:class:`google.auth.compute_engine.Credentials` or Service
Account :class:`google.oauth2.service_account.Credentials`
directly.
*New in version 0.8.0 of pandas-gbq*.
.. versionadded:: 0.24.0
See Also
--------
pandas_gbq.to_gbq : This function in the pandas-gbq library.
read_gbq : Read a DataFrame from Google BigQuery.
"""
from pandas.io import gbq
gbq.to_gbq(
self,
destination_table,
project_id=project_id,
chunksize=chunksize,
reauth=reauth,
if_exists=if_exists,
auth_local_webserver=auth_local_webserver,
table_schema=table_schema,
location=location,
progress_bar=progress_bar,
credentials=credentials,
)
@classmethod
def from_records(
cls,
data,
index=None,
exclude=None,
columns=None,
coerce_float=False,
nrows=None,
) -> "DataFrame":
"""
Convert structured or record ndarray to DataFrame.
Parameters
----------
data : ndarray (structured dtype), list of tuples, dict, or DataFrame
index : str, list of fields, array-like
Field of array to use as the index, alternately a specific set of
input labels to use.
exclude : sequence, default None
Columns or fields to exclude.
columns : sequence, default None
Column names to use. If the passed data do not have names
associated with them, this argument provides names for the
columns. Otherwise this argument indicates the order of the columns
in the result (any names not found in the data will become all-NA
columns).
coerce_float : bool, default False
Attempt to convert values of non-string, non-numeric objects (like
decimal.Decimal) to floating point, useful for SQL result sets.
nrows : int, default None
Number of rows to read if data is an iterator.
Returns
-------
DataFrame
"""
# Make a copy of the input columns so we can modify it
if columns is not None:
columns = ensure_index(columns)
if is_iterator(data):
if nrows == 0:
return cls()
try:
first_row = next(data)
except StopIteration:
return cls(index=index, columns=columns)
dtype = None
if hasattr(first_row, "dtype") and first_row.dtype.names:
dtype = first_row.dtype
values = [first_row]
if nrows is None:
values += data
else:
values.extend(itertools.islice(data, nrows - 1))
if dtype is not None:
data = np.array(values, dtype=dtype)
else:
data = values
if isinstance(data, dict):
if columns is None:
columns = arr_columns = ensure_index(sorted(data))
arrays = [data[k] for k in columns]
else:
arrays = []
arr_columns = []
for k, v in data.items():
if k in columns:
arr_columns.append(k)
arrays.append(v)
arrays, arr_columns = reorder_arrays(arrays, arr_columns, columns)
elif isinstance(data, (np.ndarray, DataFrame)):
arrays, columns = to_arrays(data, columns)
if columns is not None:
columns = ensure_index(columns)
arr_columns = columns
else:
arrays, arr_columns = to_arrays(data, columns, coerce_float=coerce_float)
arr_columns = ensure_index(arr_columns)
if columns is not None:
columns = ensure_index(columns)
else:
columns = arr_columns
if exclude is None:
exclude = set()
else:
exclude = set(exclude)
result_index = None
if index is not None:
if isinstance(index, str) or not hasattr(index, "__iter__"):
i = columns.get_loc(index)
exclude.add(index)
if len(arrays) > 0:
result_index = Index(arrays[i], name=index)
else:
result_index = Index([], name=index)
else:
try:
index_data = [arrays[arr_columns.get_loc(field)] for field in index]
except (KeyError, TypeError):
# raised by get_loc, see GH#29258
result_index = index
else:
result_index = ensure_index_from_sequences(index_data, names=index)
exclude.update(index)
if any(exclude):
arr_exclude = [x for x in exclude if x in arr_columns]
to_remove = [arr_columns.get_loc(col) for col in arr_exclude]
arrays = [v for i, v in enumerate(arrays) if i not in to_remove]
arr_columns = arr_columns.drop(arr_exclude)
columns = columns.drop(exclude)
mgr = arrays_to_mgr(arrays, arr_columns, result_index, columns)
return cls(mgr)
def to_records(
self, index=True, column_dtypes=None, index_dtypes=None
) -> np.recarray:
"""
Convert DataFrame to a NumPy record array.
Index will be included as the first field of the record array if
requested.
Parameters
----------
index : bool, default True
Include index in resulting record array, stored in 'index'
field or using the index label, if set.
column_dtypes : str, type, dict, default None
.. versionadded:: 0.24.0
If a string or type, the data type to store all columns. If
a dictionary, a mapping of column names and indices (zero-indexed)
to specific data types.
index_dtypes : str, type, dict, default None
.. versionadded:: 0.24.0
If a string or type, the data type to store all index levels. If
a dictionary, a mapping of index level names and indices
(zero-indexed) to specific data types.
This mapping is applied only if `index=True`.
Returns
-------
numpy.recarray
NumPy ndarray with the DataFrame labels as fields and each row
of the DataFrame as entries.
See Also
--------
DataFrame.from_records: Convert structured or record ndarray
to DataFrame.
numpy.recarray: An ndarray that allows field access using
attributes, analogous to typed columns in a
spreadsheet.
Examples
--------
>>> df = pd.DataFrame({'A': [1, 2], 'B': [0.5, 0.75]},
... index=['a', 'b'])
>>> df
A B
a 1 0.50
b 2 0.75
>>> df.to_records()
rec.array([('a', 1, 0.5 ), ('b', 2, 0.75)],
dtype=[('index', 'O'), ('A', '<i8'), ('B', '<f8')])
If the DataFrame index has no label then the recarray field name
is set to 'index'. If the index has a label then this is used as the
field name:
>>> df.index = df.index.rename("I")
>>> df.to_records()
rec.array([('a', 1, 0.5 ), ('b', 2, 0.75)],
dtype=[('I', 'O'), ('A', '<i8'), ('B', '<f8')])
The index can be excluded from the record array:
>>> df.to_records(index=False)
rec.array([(1, 0.5 ), (2, 0.75)],
dtype=[('A', '<i8'), ('B', '<f8')])
Data types can be specified for the columns:
>>> df.to_records(column_dtypes={"A": "int32"})
rec.array([('a', 1, 0.5 ), ('b', 2, 0.75)],
dtype=[('I', 'O'), ('A', '<i4'), ('B', '<f8')])
As well as for the index:
>>> df.to_records(index_dtypes="<S2")
rec.array([(b'a', 1, 0.5 ), (b'b', 2, 0.75)],
dtype=[('I', 'S2'), ('A', '<i8'), ('B', '<f8')])
>>> index_dtypes = f"<S{df.index.str.len().max()}"
>>> df.to_records(index_dtypes=index_dtypes)
rec.array([(b'a', 1, 0.5 ), (b'b', 2, 0.75)],
dtype=[('I', 'S1'), ('A', '<i8'), ('B', '<f8')])
"""
if index:
if isinstance(self.index, ABCMultiIndex):
# array of tuples to numpy cols. copy copy copy
ix_vals = list(map(np.array, zip(*self.index.values)))
else:
ix_vals = [self.index.values]
arrays = ix_vals + [self[c]._internal_get_values() for c in self.columns]
count = 0
index_names = list(self.index.names)
if isinstance(self.index, ABCMultiIndex):
for i, n in enumerate(index_names):
if n is None:
index_names[i] = f"level_{count}"
count += 1
elif index_names[0] is None:
index_names = ["index"]
names = [str(name) for name in itertools.chain(index_names, self.columns)]
else:
arrays = [self[c]._internal_get_values() for c in self.columns]
names = [str(c) for c in self.columns]
index_names = []
index_len = len(index_names)
formats = []
for i, v in enumerate(arrays):
index = i
# When the names and arrays are collected, we
# first collect those in the DataFrame's index,
# followed by those in its columns.
#
# Thus, the total length of the array is:
# len(index_names) + len(DataFrame.columns).
#
# This check allows us to see whether we are
# handling a name / array in the index or column.
if index < index_len:
dtype_mapping = index_dtypes
name = index_names[index]
else:
index -= index_len
dtype_mapping = column_dtypes
name = self.columns[index]
# We have a dictionary, so we get the data type
# associated with the index or column (which can
# be denoted by its name in the DataFrame or its
# position in DataFrame's array of indices or
# columns, whichever is applicable.
if is_dict_like(dtype_mapping):
if name in dtype_mapping:
dtype_mapping = dtype_mapping[name]
elif index in dtype_mapping:
dtype_mapping = dtype_mapping[index]
else:
dtype_mapping = None
# If no mapping can be found, use the array's
# dtype attribute for formatting.
#
# A valid dtype must either be a type or
# string naming a type.
if dtype_mapping is None:
formats.append(v.dtype)
elif isinstance(dtype_mapping, (type, np.dtype, str)):
formats.append(dtype_mapping)
else:
element = "row" if i < index_len else "column"
msg = f"Invalid dtype {dtype_mapping} specified for {element} {name}"
raise ValueError(msg)
return np.rec.fromarrays(arrays, dtype={"names": names, "formats": formats})
@classmethod
def _from_arrays(cls, arrays, columns, index, dtype=None) -> "DataFrame":
mgr = arrays_to_mgr(arrays, columns, index, columns, dtype=dtype)
return cls(mgr)
@deprecate_kwarg(old_arg_name="fname", new_arg_name="path")
def to_stata(
self,
path,
convert_dates=None,
write_index=True,
byteorder=None,
time_stamp=None,
data_label=None,
variable_labels=None,
version=114,
convert_strl=None,
):
"""
Export DataFrame object to Stata dta format.
Writes the DataFrame to a Stata dataset file.
"dta" files contain a Stata dataset.
Parameters
----------
path : str, buffer or path object
String, path object (pathlib.Path or py._path.local.LocalPath) or
object implementing a binary write() function. If using a buffer
then the buffer will not be automatically closed after the file
data has been written.
.. versionchanged:: 1.0.0
Previously this was "fname"
convert_dates : dict
Dictionary mapping columns containing datetime types to stata
internal format to use when writing the dates. Options are 'tc',
'td', 'tm', 'tw', 'th', 'tq', 'ty'. Column can be either an integer
or a name. Datetime columns that do not have a conversion type
specified will be converted to 'tc'. Raises NotImplementedError if
a datetime column has timezone information.
write_index : bool
Write the index to Stata dataset.
byteorder : str
Can be ">", "<", "little", or "big". default is `sys.byteorder`.
time_stamp : datetime
A datetime to use as file creation date. Default is the current
time.
data_label : str, optional
A label for the data set. Must be 80 characters or smaller.
variable_labels : dict
Dictionary containing columns as keys and variable labels as
values. Each label must be 80 characters or smaller.
version : {114, 117, 118, 119, None}, default 114
Version to use in the output dta file. Set to None to let pandas
decide between 118 or 119 formats depending on the number of
columns in the frame. Version 114 can be read by Stata 10 and
later. Version 117 can be read by Stata 13 or later. Version 118
is supported in Stata 14 and later. Version 119 is supported in
Stata 15 and later. Version 114 limits string variables to 244
characters or fewer while versions 117 and later allow strings
with lengths up to 2,000,000 characters. Versions 118 and 119
support Unicode characters, and version 119 supports more than
32,767 variables.
.. versionadded:: 0.23.0
.. versionchanged:: 1.0.0
Added support for formats 118 and 119.
convert_strl : list, optional
List of column names to convert to string columns to Stata StrL
format. Only available if version is 117. Storing strings in the
StrL format can produce smaller dta files if strings have more than
8 characters and values are repeated.
.. versionadded:: 0.23.0
Raises
------
NotImplementedError
* If datetimes contain timezone information
* Column dtype is not representable in Stata
ValueError
* Columns listed in convert_dates are neither datetime64[ns]
or datetime.datetime
* Column listed in convert_dates is not in DataFrame
* Categorical label contains more than 32,000 characters
See Also
--------
read_stata : Import Stata data files.
io.stata.StataWriter : Low-level writer for Stata data files.
io.stata.StataWriter117 : Low-level writer for version 117 files.
Examples
--------
>>> df = pd.DataFrame({'animal': ['falcon', 'parrot', 'falcon',
... 'parrot'],
... 'speed': [350, 18, 361, 15]})
>>> df.to_stata('animals.dta') # doctest: +SKIP
"""
if version not in (114, 117, 118, 119, None):
raise ValueError("Only formats 114, 117, 118 and 119 are supported.")
if version == 114:
if convert_strl is not None:
raise ValueError("strl is not supported in format 114")
from pandas.io.stata import StataWriter as statawriter
elif version == 117:
from pandas.io.stata import StataWriter117 as statawriter
else: # versions 118 and 119
from pandas.io.stata import StataWriterUTF8 as statawriter
kwargs = {}
if version is None or version >= 117:
# strl conversion is only supported >= 117
kwargs["convert_strl"] = convert_strl
if version is None or version >= 118:
# Specifying the version is only supported for UTF8 (118 or 119)
kwargs["version"] = version
writer = statawriter(
path,
self,
convert_dates=convert_dates,
byteorder=byteorder,
time_stamp=time_stamp,
data_label=data_label,
write_index=write_index,
variable_labels=variable_labels,
**kwargs,
)
writer.write_file()
@deprecate_kwarg(old_arg_name="fname", new_arg_name="path")
def to_feather(self, path) -> None:
"""
Write out the binary feather-format for DataFrames.
Parameters
----------
path : str
String file path.
"""
from pandas.io.feather_format import to_feather
to_feather(self, path)
@Appender(
"""
Examples
--------
>>> df = pd.DataFrame(
... data={"animal_1": ["elk", "pig"], "animal_2": ["dog", "quetzal"]}
... )
>>> print(df.to_markdown())
| | animal_1 | animal_2 |
|---:|:-----------|:-----------|
| 0 | elk | dog |
| 1 | pig | quetzal |
"""
)
@Substitution(klass="DataFrame")
@Appender(_shared_docs["to_markdown"])
def to_markdown(
self, buf: Optional[IO[str]] = None, mode: Optional[str] = None, **kwargs
) -> Optional[str]:
kwargs.setdefault("headers", "keys")
kwargs.setdefault("tablefmt", "pipe")
tabulate = import_optional_dependency("tabulate")
result = tabulate.tabulate(self, **kwargs)
if buf is None:
return result
buf, _, _, _ = get_filepath_or_buffer(buf, mode=mode)
assert buf is not None # Help mypy.
buf.writelines(result)
return None
@deprecate_kwarg(old_arg_name="fname", new_arg_name="path")
def to_parquet(
self,
path,
engine="auto",
compression="snappy",
index=None,
partition_cols=None,
**kwargs,
) -> None:
"""
Write a DataFrame to the binary parquet format.
.. versionadded:: 0.21.0
This function writes the dataframe as a `parquet file
<https://parquet.apache.org/>`_. You can choose different parquet
backends, and have the option of compression. See
:ref:`the user guide <io.parquet>` for more details.
Parameters
----------
path : str
File path or Root Directory path. Will be used as Root Directory
path while writing a partitioned dataset.
.. versionchanged:: 1.0.0
Previously this was "fname"
engine : {'auto', 'pyarrow', 'fastparquet'}, default 'auto'
Parquet library to use. If 'auto', then the option
``io.parquet.engine`` is used. The default ``io.parquet.engine``
behavior is to try 'pyarrow', falling back to 'fastparquet' if
'pyarrow' is unavailable.
compression : {'snappy', 'gzip', 'brotli', None}, default 'snappy'
Name of the compression to use. Use ``None`` for no compression.
index : bool, default None
If ``True``, include the dataframe's index(es) in the file output.
If ``False``, they will not be written to the file.
If ``None``, similar to ``True`` the dataframe's index(es)
will be saved. However, instead of being saved as values,
the RangeIndex will be stored as a range in the metadata so it
doesn't require much space and is faster. Other indexes will
be included as columns in the file output.
.. versionadded:: 0.24.0
partition_cols : list, optional, default None
Column names by which to partition the dataset.
Columns are partitioned in the order they are given.
.. versionadded:: 0.24.0
**kwargs
Additional arguments passed to the parquet library. See
:ref:`pandas io <io.parquet>` for more details.
See Also
--------
read_parquet : Read a parquet file.
DataFrame.to_csv : Write a csv file.
DataFrame.to_sql : Write to a sql table.
DataFrame.to_hdf : Write to hdf.
Notes
-----
This function requires either the `fastparquet
<https://pypi.org/project/fastparquet>`_ or `pyarrow
<https://arrow.apache.org/docs/python/>`_ library.
Examples
--------
>>> df = pd.DataFrame(data={'col1': [1, 2], 'col2': [3, 4]})
>>> df.to_parquet('df.parquet.gzip',
... compression='gzip') # doctest: +SKIP
>>> pd.read_parquet('df.parquet.gzip') # doctest: +SKIP
col1 col2
0 1 3
1 2 4
"""
from pandas.io.parquet import to_parquet
to_parquet(
self,
path,
engine,
compression=compression,
index=index,
partition_cols=partition_cols,
**kwargs,
)
@Substitution(
header_type="bool",
header="Whether to print column labels, default True",
col_space_type="str or int",
col_space="The minimum width of each column in CSS length "
"units. An int is assumed to be px units.\n\n"
" .. versionadded:: 0.25.0\n"
" Ability to use str",
)
@Substitution(shared_params=fmt.common_docstring, returns=fmt.return_docstring)
def to_html(
self,
buf=None,
columns=None,
col_space=None,
header=True,
index=True,
na_rep="NaN",
formatters=None,
float_format=None,
sparsify=None,
index_names=True,
justify=None,
max_rows=None,
max_cols=None,
show_dimensions=False,
decimal=".",
bold_rows=True,
classes=None,
escape=True,
notebook=False,
border=None,
table_id=None,
render_links=False,
encoding=None,
):
"""
Render a DataFrame as an HTML table.
%(shared_params)s
bold_rows : bool, default True
Make the row labels bold in the output.
classes : str or list or tuple, default None
CSS class(es) to apply to the resulting html table.
escape : bool, default True
Convert the characters <, >, and & to HTML-safe sequences.
notebook : {True, False}, default False
Whether the generated HTML is for IPython Notebook.
border : int
A ``border=border`` attribute is included in the opening
`<table>` tag. Default ``pd.options.display.html.border``.
encoding : str, default "utf-8"
Set character encoding.
.. versionadded:: 1.0
table_id : str, optional
A css id is included in the opening `<table>` tag if specified.
.. versionadded:: 0.23.0
render_links : bool, default False
Convert URLs to HTML links.
.. versionadded:: 0.24.0
%(returns)s
See Also
--------
to_string : Convert DataFrame to a string.
"""
if justify is not None and justify not in fmt._VALID_JUSTIFY_PARAMETERS:
raise ValueError("Invalid value for justify parameter")
formatter = fmt.DataFrameFormatter(
self,
columns=columns,
col_space=col_space,
na_rep=na_rep,
formatters=formatters,
float_format=float_format,
sparsify=sparsify,
justify=justify,
index_names=index_names,
header=header,
index=index,
bold_rows=bold_rows,
escape=escape,
max_rows=max_rows,
max_cols=max_cols,
show_dimensions=show_dimensions,
decimal=decimal,
table_id=table_id,
render_links=render_links,
)
# TODO: a generic formatter wld b in DataFrameFormatter
return formatter.to_html(
buf=buf,
classes=classes,
notebook=notebook,
border=border,
encoding=encoding,
)
# ----------------------------------------------------------------------
def info(
self, verbose=None, buf=None, max_cols=None, memory_usage=None, null_counts=None
) -> None:
"""
Print a concise summary of a DataFrame.
This method prints information about a DataFrame including
the index dtype and column dtypes, non-null values and memory usage.
Parameters
----------
verbose : bool, optional
Whether to print the full summary. By default, the setting in
``pandas.options.display.max_info_columns`` is followed.
buf : writable buffer, defaults to sys.stdout
Where to send the output. By default, the output is printed to
sys.stdout. Pass a writable buffer if you need to further process
the output.
max_cols : int, optional
When to switch from the verbose to the truncated output. If the
DataFrame has more than `max_cols` columns, the truncated output
is used. By default, the setting in
``pandas.options.display.max_info_columns`` is used.
memory_usage : bool, str, optional
Specifies whether total memory usage of the DataFrame
elements (including the index) should be displayed. By default,
this follows the ``pandas.options.display.memory_usage`` setting.
True always show memory usage. False never shows memory usage.
A value of 'deep' is equivalent to "True with deep introspection".
Memory usage is shown in human-readable units (base-2
representation). Without deep introspection a memory estimation is
made based in column dtype and number of rows assuming values
consume the same memory amount for corresponding dtypes. With deep
memory introspection, a real memory usage calculation is performed
at the cost of computational resources.
null_counts : bool, optional
Whether to show the non-null counts. By default, this is shown
only if the frame is smaller than
``pandas.options.display.max_info_rows`` and
``pandas.options.display.max_info_columns``. A value of True always
shows the counts, and False never shows the counts.
Returns
-------
None
This method prints a summary of a DataFrame and returns None.
See Also
--------
DataFrame.describe: Generate descriptive statistics of DataFrame
columns.
DataFrame.memory_usage: Memory usage of DataFrame columns.
Examples
--------
>>> int_values = [1, 2, 3, 4, 5]
>>> text_values = ['alpha', 'beta', 'gamma', 'delta', 'epsilon']
>>> float_values = [0.0, 0.25, 0.5, 0.75, 1.0]
>>> df = pd.DataFrame({"int_col": int_values, "text_col": text_values,
... "float_col": float_values})
>>> df
int_col text_col float_col
0 1 alpha 0.00
1 2 beta 0.25
2 3 gamma 0.50
3 4 delta 0.75
4 5 epsilon 1.00
Prints information of all columns:
>>> df.info(verbose=True)
<class 'pandas.core.frame.DataFrame'>
RangeIndex: 5 entries, 0 to 4
Data columns (total 3 columns):
# Column Non-Null Count Dtype
--- ------ -------------- -----
0 int_col 5 non-null int64
1 text_col 5 non-null object
2 float_col 5 non-null float64
dtypes: float64(1), int64(1), object(1)
memory usage: 248.0+ bytes
Prints a summary of columns count and its dtypes but not per column
information:
>>> df.info(verbose=False)
<class 'pandas.core.frame.DataFrame'>
RangeIndex: 5 entries, 0 to 4
Columns: 3 entries, int_col to float_col
dtypes: float64(1), int64(1), object(1)
memory usage: 248.0+ bytes
Pipe output of DataFrame.info to buffer instead of sys.stdout, get
buffer content and writes to a text file:
>>> import io
>>> buffer = io.StringIO()
>>> df.info(buf=buffer)
>>> s = buffer.getvalue()
>>> with open("df_info.txt", "w",
... encoding="utf-8") as f: # doctest: +SKIP
... f.write(s)
260
The `memory_usage` parameter allows deep introspection mode, specially
useful for big DataFrames and fine-tune memory optimization:
>>> random_strings_array = np.random.choice(['a', 'b', 'c'], 10 ** 6)
>>> df = pd.DataFrame({
... 'column_1': np.random.choice(['a', 'b', 'c'], 10 ** 6),
... 'column_2': np.random.choice(['a', 'b', 'c'], 10 ** 6),
... 'column_3': np.random.choice(['a', 'b', 'c'], 10 ** 6)
... })
>>> df.info()
<class 'pandas.core.frame.DataFrame'>
RangeIndex: 1000000 entries, 0 to 999999
Data columns (total 3 columns):
# Column Non-Null Count Dtype
--- ------ -------------- -----
0 column_1 1000000 non-null object
1 column_2 1000000 non-null object
2 column_3 1000000 non-null object
dtypes: object(3)
memory usage: 22.9+ MB
>>> df.info(memory_usage='deep')
<class 'pandas.core.frame.DataFrame'>
RangeIndex: 1000000 entries, 0 to 999999
Data columns (total 3 columns):
# Column Non-Null Count Dtype
--- ------ -------------- -----
0 column_1 1000000 non-null object
1 column_2 1000000 non-null object
2 column_3 1000000 non-null object
dtypes: object(3)
memory usage: 188.8 MB
"""
if buf is None: # pragma: no cover
buf = sys.stdout
lines = []
lines.append(str(type(self)))
lines.append(self.index._summary())
if len(self.columns) == 0:
lines.append(f"Empty {type(self).__name__}")
fmt.buffer_put_lines(buf, lines)
return
cols = self.columns
col_count = len(self.columns)
# hack
if max_cols is None:
max_cols = get_option("display.max_info_columns", len(self.columns) + 1)
max_rows = get_option("display.max_info_rows", len(self) + 1)
if null_counts is None:
show_counts = (col_count <= max_cols) and (len(self) < max_rows)
else:
show_counts = null_counts
exceeds_info_cols = col_count > max_cols
def _verbose_repr():
lines.append(f"Data columns (total {len(self.columns)} columns):")
id_head = " # "
column_head = "Column"
col_space = 2
max_col = max(len(pprint_thing(k)) for k in cols)
len_column = len(pprint_thing(column_head))
space = max(max_col, len_column) + col_space
max_id = len(pprint_thing(col_count))
len_id = len(pprint_thing(id_head))
space_num = max(max_id, len_id) + col_space
counts = None
header = _put_str(id_head, space_num) + _put_str(column_head, space)
if show_counts:
counts = self.count()
if len(cols) != len(counts): # pragma: no cover
raise AssertionError(
f"Columns must equal counts ({len(cols)} != {len(counts)})"
)
count_header = "Non-Null Count"
len_count = len(count_header)
non_null = " non-null"
max_count = max(len(pprint_thing(k)) for k in counts) + len(non_null)
space_count = max(len_count, max_count) + col_space
count_temp = "{count}" + non_null
else:
count_header = ""
space_count = len(count_header)
len_count = space_count
count_temp = "{count}"
dtype_header = "Dtype"
len_dtype = len(dtype_header)
max_dtypes = max(len(pprint_thing(k)) for k in self.dtypes)
space_dtype = max(len_dtype, max_dtypes)
header += _put_str(count_header, space_count) + _put_str(
dtype_header, space_dtype
)
lines.append(header)
lines.append(
_put_str("-" * len_id, space_num)
+ _put_str("-" * len_column, space)
+ _put_str("-" * len_count, space_count)
+ _put_str("-" * len_dtype, space_dtype)
)
for i, col in enumerate(self.columns):
dtype = self.dtypes.iloc[i]
col = pprint_thing(col)
line_no = _put_str(f" {i}", space_num)
count = ""
if show_counts:
count = counts.iloc[i]
lines.append(
line_no
+ _put_str(col, space)
+ _put_str(count_temp.format(count=count), space_count)
+ _put_str(dtype, space_dtype)
)
def _non_verbose_repr():
lines.append(self.columns._summary(name="Columns"))
def _sizeof_fmt(num, size_qualifier):
# returns size in human readable format
for x in ["bytes", "KB", "MB", "GB", "TB"]:
if num < 1024.0:
return f"{num:3.1f}{size_qualifier} {x}"
num /= 1024.0
return f"{num:3.1f}{size_qualifier} PB"
if verbose:
_verbose_repr()
elif verbose is False: # specifically set to False, not nesc None
_non_verbose_repr()
else:
if exceeds_info_cols:
_non_verbose_repr()
else:
_verbose_repr()
counts = self._data.get_dtype_counts()
dtypes = [f"{k[0]}({k[1]:d})" for k in sorted(counts.items())]
lines.append(f"dtypes: {', '.join(dtypes)}")
if memory_usage is None:
memory_usage = get_option("display.memory_usage")
if memory_usage:
# append memory usage of df to display
size_qualifier = ""
if memory_usage == "deep":
deep = True
else:
# size_qualifier is just a best effort; not guaranteed to catch
# all cases (e.g., it misses categorical data even with object
# categories)
deep = False
if "object" in counts or self.index._is_memory_usage_qualified():
size_qualifier = "+"
mem_usage = self.memory_usage(index=True, deep=deep).sum()
lines.append(f"memory usage: {_sizeof_fmt(mem_usage, size_qualifier)}\n")
fmt.buffer_put_lines(buf, lines)
def memory_usage(self, index=True, deep=False) -> Series:
"""
Return the memory usage of each column in bytes.
The memory usage can optionally include the contribution of
the index and elements of `object` dtype.
This value is displayed in `DataFrame.info` by default. This can be
suppressed by setting ``pandas.options.display.memory_usage`` to False.
Parameters
----------
index : bool, default True
Specifies whether to include the memory usage of the DataFrame's
index in returned Series. If ``index=True``, the memory usage of
the index is the first item in the output.
deep : bool, default False
If True, introspect the data deeply by interrogating
`object` dtypes for system-level memory consumption, and include
it in the returned values.
Returns
-------
Series
A Series whose index is the original column names and whose values
is the memory usage of each column in bytes.
See Also
--------
numpy.ndarray.nbytes : Total bytes consumed by the elements of an
ndarray.
Series.memory_usage : Bytes consumed by a Series.
Categorical : Memory-efficient array for string values with
many repeated values.
DataFrame.info : Concise summary of a DataFrame.
Examples
--------
>>> dtypes = ['int64', 'float64', 'complex128', 'object', 'bool']
>>> data = dict([(t, np.ones(shape=5000).astype(t))
... for t in dtypes])
>>> df = pd.DataFrame(data)
>>> df.head()
int64 float64 complex128 object bool
0 1 1.0 1.000000+0.000000j 1 True
1 1 1.0 1.000000+0.000000j 1 True
2 1 1.0 1.000000+0.000000j 1 True
3 1 1.0 1.000000+0.000000j 1 True
4 1 1.0 1.000000+0.000000j 1 True
>>> df.memory_usage()
Index 128
int64 40000
float64 40000
complex128 80000
object 40000
bool 5000
dtype: int64
>>> df.memory_usage(index=False)
int64 40000
float64 40000
complex128 80000
object 40000
bool 5000
dtype: int64
The memory footprint of `object` dtype columns is ignored by default:
>>> df.memory_usage(deep=True)
Index 128
int64 40000
float64 40000
complex128 80000
object 160000
bool 5000
dtype: int64
Use a Categorical for efficient storage of an object-dtype column with
many repeated values.
>>> df['object'].astype('category').memory_usage(deep=True)
5216
"""
result = Series(
[c.memory_usage(index=False, deep=deep) for col, c in self.items()],
index=self.columns,
)
if index:
result = Series(self.index.memory_usage(deep=deep), index=["Index"]).append(
result
)
return result
def transpose(self, *args, copy: bool = False) -> "DataFrame":
"""
Transpose index and columns.
Reflect the DataFrame over its main diagonal by writing rows as columns
and vice-versa. The property :attr:`.T` is an accessor to the method
:meth:`transpose`.
Parameters
----------
*args : tuple, optional
Accepted for compatibility with NumPy.
copy : bool, default False
Whether to copy the data after transposing, even for DataFrames
with a single dtype.
Note that a copy is always required for mixed dtype DataFrames,
or for DataFrames with any extension types.
Returns
-------
DataFrame
The transposed DataFrame.
See Also
--------
numpy.transpose : Permute the dimensions of a given array.
Notes
-----
Transposing a DataFrame with mixed dtypes will result in a homogeneous
DataFrame with the `object` dtype. In such a case, a copy of the data
is always made.
Examples
--------
**Square DataFrame with homogeneous dtype**
>>> d1 = {'col1': [1, 2], 'col2': [3, 4]}
>>> df1 = pd.DataFrame(data=d1)
>>> df1
col1 col2
0 1 3
1 2 4
>>> df1_transposed = df1.T # or df1.transpose()
>>> df1_transposed
0 1
col1 1 2
col2 3 4
When the dtype is homogeneous in the original DataFrame, we get a
transposed DataFrame with the same dtype:
>>> df1.dtypes
col1 int64
col2 int64
dtype: object
>>> df1_transposed.dtypes
0 int64
1 int64
dtype: object
**Non-square DataFrame with mixed dtypes**
>>> d2 = {'name': ['Alice', 'Bob'],
... 'score': [9.5, 8],
... 'employed': [False, True],
... 'kids': [0, 0]}
>>> df2 = pd.DataFrame(data=d2)
>>> df2
name score employed kids
0 Alice 9.5 False 0
1 Bob 8.0 True 0
>>> df2_transposed = df2.T # or df2.transpose()
>>> df2_transposed
0 1
name Alice Bob
score 9.5 8
employed False True
kids 0 0
When the DataFrame has mixed dtypes, we get a transposed DataFrame with
the `object` dtype:
>>> df2.dtypes
name object
score float64
employed bool
kids int64
dtype: object
>>> df2_transposed.dtypes
0 object
1 object
dtype: object
"""
nv.validate_transpose(args, dict())
# construct the args
dtypes = list(self.dtypes)
if self._is_homogeneous_type and dtypes and is_extension_array_dtype(dtypes[0]):
# We have EAs with the same dtype. We can preserve that dtype in transpose.
dtype = dtypes[0]
arr_type = dtype.construct_array_type()
values = self.values
new_values = [arr_type._from_sequence(row, dtype=dtype) for row in values]
result = self._constructor(
dict(zip(self.index, new_values)), index=self.columns
)
else:
new_values = self.values.T
if copy:
new_values = new_values.copy()
result = self._constructor(
new_values, index=self.columns, columns=self.index
)
return result.__finalize__(self)
T = property(transpose)
# ----------------------------------------------------------------------
# Indexing Methods
def _ixs(self, i: int, axis: int = 0):
"""
Parameters
----------
i : int
axis : int
Notes
-----
If slice passed, the resulting data will be a view.
"""
# irow
if axis == 0:
new_values = self._data.fast_xs(i)
# if we are a copy, mark as such
copy = isinstance(new_values, np.ndarray) and new_values.base is None
result = self._constructor_sliced(
new_values,
index=self.columns,
name=self.index[i],
dtype=new_values.dtype,
)
result._set_is_copy(self, copy=copy)
return result
# icol
else:
label = self.columns[i]
values = self._data.iget(i)
result = self._box_col_values(values, label)
# this is a cached value, mark it so
result._set_as_cached(label, self)
return result
def __getitem__(self, key):
key = lib.item_from_zerodim(key)
key = com.apply_if_callable(key, self)
if is_hashable(key):
# shortcut if the key is in columns
if self.columns.is_unique and key in self.columns:
if self.columns.nlevels > 1:
return self._getitem_multilevel(key)
return self._get_item_cache(key)
# Do we have a slicer (on rows)?
indexer = convert_to_index_sliceable(self, key)
if indexer is not None:
# either we have a slice or we have a string that can be converted
# to a slice for partial-string date indexing
return self._slice(indexer, axis=0)
# Do we have a (boolean) DataFrame?
if isinstance(key, DataFrame):
return self.where(key)
# Do we have a (boolean) 1d indexer?
if com.is_bool_indexer(key):
return self._getitem_bool_array(key)
# We are left with two options: a single key, and a collection of keys,
# We interpret tuples as collections only for non-MultiIndex
is_single_key = isinstance(key, tuple) or not is_list_like(key)
if is_single_key:
if self.columns.nlevels > 1:
return self._getitem_multilevel(key)
indexer = self.columns.get_loc(key)
if is_integer(indexer):
indexer = [indexer]
else:
if is_iterator(key):
key = list(key)
indexer = self.loc._get_listlike_indexer(key, axis=1, raise_missing=True)[1]
# take() does not accept boolean indexers
if getattr(indexer, "dtype", None) == bool:
indexer = np.where(indexer)[0]
data = self.take(indexer, axis=1)
if is_single_key:
# What does looking for a single key in a non-unique index return?
# The behavior is inconsistent. It returns a Series, except when
# - the key itself is repeated (test on data.shape, #9519), or
# - we have a MultiIndex on columns (test on self.columns, #21309)
if data.shape[1] == 1 and not isinstance(self.columns, ABCMultiIndex):
data = data[key]
return data
def _getitem_bool_array(self, key):
# also raises Exception if object array with NA values
# warning here just in case -- previously __setitem__ was
# reindexing but __getitem__ was not; it seems more reasonable to
# go with the __setitem__ behavior since that is more consistent
# with all other indexing behavior
if isinstance(key, Series) and not key.index.equals(self.index):
warnings.warn(
"Boolean Series key will be reindexed to match DataFrame index.",
UserWarning,
stacklevel=3,
)
elif len(key) != len(self.index):
raise ValueError(
f"Item wrong length {len(key)} instead of {len(self.index)}."
)
# check_bool_indexer will throw exception if Series key cannot
# be reindexed to match DataFrame rows
key = check_bool_indexer(self.index, key)
indexer = key.nonzero()[0]
return self.take(indexer, axis=0)
def _getitem_multilevel(self, key):
# self.columns is a MultiIndex
loc = self.columns.get_loc(key)
if isinstance(loc, (slice, Series, np.ndarray, Index)):
new_columns = self.columns[loc]
result_columns = maybe_droplevels(new_columns, key)
if self._is_mixed_type:
result = self.reindex(columns=new_columns)
result.columns = result_columns
else:
new_values = self.values[:, loc]
result = self._constructor(
new_values, index=self.index, columns=result_columns
)
result = result.__finalize__(self)
# If there is only one column being returned, and its name is
# either an empty string, or a tuple with an empty string as its
# first element, then treat the empty string as a placeholder
# and return the column as if the user had provided that empty
# string in the key. If the result is a Series, exclude the
# implied empty string from its name.
if len(result.columns) == 1:
top = result.columns[0]
if isinstance(top, tuple):
top = top[0]
if top == "":
result = result[""]
if isinstance(result, Series):
result = self._constructor_sliced(
result, index=self.index, name=key
)
result._set_is_copy(self)
return result
else:
return self._get_item_cache(key)
def _get_value(self, index, col, takeable: bool = False):
"""
Quickly retrieve single value at passed column and index.
Parameters
----------
index : row label
col : column label
takeable : interpret the index/col as indexers, default False
Returns
-------
scalar
"""
if takeable:
series = self._iget_item_cache(col)
return com.maybe_box_datetimelike(series._values[index])
series = self._get_item_cache(col)
engine = self.index._engine
try:
if isinstance(series._values, np.ndarray):
# i.e. not EA, we can use engine
return engine.get_value(series._values, index)
else:
loc = series.index.get_loc(index)
return series._values[loc]
except KeyError:
# GH 20629
if self.index.nlevels > 1:
# partial indexing forbidden
raise
# we cannot handle direct indexing
# use positional
col = self.columns.get_loc(col)
index = self.index.get_loc(index)
return self._get_value(index, col, takeable=True)
def __setitem__(self, key, value):
key = com.apply_if_callable(key, self)
# see if we can slice the rows
indexer = convert_to_index_sliceable(self, key)
if indexer is not None:
# either we have a slice or we have a string that can be converted
# to a slice for partial-string date indexing
return self._setitem_slice(indexer, value)
if isinstance(key, DataFrame) or getattr(key, "ndim", None) == 2:
self._setitem_frame(key, value)
elif isinstance(key, (Series, np.ndarray, list, Index)):
self._setitem_array(key, value)
else:
# set column
self._set_item(key, value)
def _setitem_slice(self, key, value):
self._check_setitem_copy()
self.loc[key] = value
def _setitem_array(self, key, value):
# also raises Exception if object array with NA values
if com.is_bool_indexer(key):
if len(key) != len(self.index):
raise ValueError(
f"Item wrong length {len(key)} instead of {len(self.index)}!"
)
key = check_bool_indexer(self.index, key)
indexer = key.nonzero()[0]
self._check_setitem_copy()
self.loc._setitem_with_indexer(indexer, value)
else:
if isinstance(value, DataFrame):
if len(value.columns) != len(key):
raise ValueError("Columns must be same length as key")
for k1, k2 in zip(key, value.columns):
self[k1] = value[k2]
else:
indexer = self.loc._get_listlike_indexer(
key, axis=1, raise_missing=False
)[1]
self._check_setitem_copy()
self.loc._setitem_with_indexer((slice(None), indexer), value)
def _setitem_frame(self, key, value):
# support boolean setting with DataFrame input, e.g.
# df[df > df2] = 0
if isinstance(key, np.ndarray):
if key.shape != self.shape:
raise ValueError("Array conditional must be same shape as self")
key = self._constructor(key, **self._construct_axes_dict())
if key.values.size and not is_bool_dtype(key.values):
raise TypeError(
"Must pass DataFrame or 2-d ndarray with boolean values only"
)
self._check_inplace_setting(value)
self._check_setitem_copy()
self._where(-key, value, inplace=True)
def _set_item(self, key, value):
"""
Add series to DataFrame in specified column.
If series is a numpy-array (not a Series/TimeSeries), it must be the
same length as the DataFrames index or an error will be thrown.
Series/TimeSeries will be conformed to the DataFrames index to
ensure homogeneity.
"""
self._ensure_valid_index(value)
value = self._sanitize_column(key, value)
NDFrame._set_item(self, key, value)
# check if we are modifying a copy
# try to set first as we want an invalid
# value exception to occur first
if len(self):
self._check_setitem_copy()
def _set_value(self, index, col, value, takeable: bool = False):
"""
Put single value at passed column and index.
Parameters
----------
index : row label
col : column label
value : scalar
takeable : interpret the index/col as indexers, default False
Returns
-------
DataFrame
If label pair is contained, will be reference to calling DataFrame,
otherwise a new object.
"""
try:
if takeable is True:
series = self._iget_item_cache(col)
return series._set_value(index, value, takeable=True)
series = self._get_item_cache(col)
engine = self.index._engine
engine.set_value(series._values, index, value)
return self
except (KeyError, TypeError):
# set using a non-recursive method & reset the cache
if takeable:
self.iloc[index, col] = value
else:
self.loc[index, col] = value
self._item_cache.pop(col, None)
return self
def _ensure_valid_index(self, value):
"""
Ensure that if we don't have an index, that we can create one from the
passed value.
"""
# GH5632, make sure that we are a Series convertible
if not len(self.index) and is_list_like(value) and len(value):
try:
value = Series(value)
except (ValueError, NotImplementedError, TypeError):
raise ValueError(
"Cannot set a frame with no defined index "
"and a value that cannot be converted to a Series"
)
self._data = self._data.reindex_axis(
value.index.copy(), axis=1, fill_value=np.nan
)
def _box_item_values(self, key, values):
items = self.columns[self.columns.get_loc(key)]
if values.ndim == 2:
return self._constructor(values.T, columns=items, index=self.index)
else:
return self._box_col_values(values, items)
def _box_col_values(self, values, items):
"""
Provide boxed values for a column.
"""
klass = self._constructor_sliced
return klass(values, index=self.index, name=items, fastpath=True)
# ----------------------------------------------------------------------
# Unsorted
def query(self, expr, inplace=False, **kwargs):
"""
Query the columns of a DataFrame with a boolean expression.
Parameters
----------
expr : str
The query string to evaluate.
You can refer to variables
in the environment by prefixing them with an '@' character like
``@a + b``.
You can refer to column names that contain spaces or operators by
surrounding them in backticks. This way you can also escape
names that start with a digit, or those that are a Python keyword.
Basically when it is not valid Python identifier. See notes down
for more details.
For example, if one of your columns is called ``a a`` and you want
to sum it with ``b``, your query should be ```a a` + b``.
.. versionadded:: 0.25.0
Backtick quoting introduced.
.. versionadded:: 1.0.0
Expanding functionality of backtick quoting for more than only spaces.
inplace : bool
Whether the query should modify the data in place or return
a modified copy.
**kwargs
See the documentation for :func:`eval` for complete details
on the keyword arguments accepted by :meth:`DataFrame.query`.
Returns
-------
DataFrame
DataFrame resulting from the provided query expression.
See Also
--------
eval : Evaluate a string describing operations on
DataFrame columns.
DataFrame.eval : Evaluate a string describing operations on
DataFrame columns.
Notes
-----
The result of the evaluation of this expression is first passed to
:attr:`DataFrame.loc` and if that fails because of a
multidimensional key (e.g., a DataFrame) then the result will be passed
to :meth:`DataFrame.__getitem__`.
This method uses the top-level :func:`eval` function to
evaluate the passed query.
The :meth:`~pandas.DataFrame.query` method uses a slightly
modified Python syntax by default. For example, the ``&`` and ``|``
(bitwise) operators have the precedence of their boolean cousins,
:keyword:`and` and :keyword:`or`. This *is* syntactically valid Python,
however the semantics are different.
You can change the semantics of the expression by passing the keyword
argument ``parser='python'``. This enforces the same semantics as
evaluation in Python space. Likewise, you can pass ``engine='python'``
to evaluate an expression using Python itself as a backend. This is not
recommended as it is inefficient compared to using ``numexpr`` as the
engine.
The :attr:`DataFrame.index` and
:attr:`DataFrame.columns` attributes of the
:class:`~pandas.DataFrame` instance are placed in the query namespace
by default, which allows you to treat both the index and columns of the
frame as a column in the frame.
The identifier ``index`` is used for the frame index; you can also
use the name of the index to identify it in a query. Please note that
Python keywords may not be used as identifiers.
For further details and examples see the ``query`` documentation in
:ref:`indexing <indexing.query>`.
*Backtick quoted variables*
Backtick quoted variables are parsed as literal Python code and
are converted internally to a Python valid identifier.
This can lead to the following problems.
During parsing a number of disallowed characters inside the backtick
quoted string are replaced by strings that are allowed as a Python identifier.
These characters include all operators in Python, the space character, the
question mark, the exclamation mark, the dollar sign, and the euro sign.
For other characters that fall outside the ASCII range (U+0001..U+007F)
and those that are not further specified in PEP 3131,
the query parser will raise an error.
This excludes whitespace different than the space character,
but also the hashtag (as it is used for comments) and the backtick
itself (backtick can also not be escaped).
In a special case, quotes that make a pair around a backtick can
confuse the parser.
For example, ```it's` > `that's``` will raise an error,
as it forms a quoted string (``'s > `that'``) with a backtick inside.
See also the Python documentation about lexical analysis
(https://docs.python.org/3/reference/lexical_analysis.html)
in combination with the source code in :mod:`pandas.core.computation.parsing`.
Examples
--------
>>> df = pd.DataFrame({'A': range(1, 6),
... 'B': range(10, 0, -2),
... 'C C': range(10, 5, -1)})
>>> df
A B C C
0 1 10 10
1 2 8 9
2 3 6 8
3 4 4 7
4 5 2 6
>>> df.query('A > B')
A B C C
4 5 2 6
The previous expression is equivalent to
>>> df[df.A > df.B]
A B C C
4 5 2 6
For columns with spaces in their name, you can use backtick quoting.
>>> df.query('B == `C C`')
A B C C
0 1 10 10
The previous expression is equivalent to
>>> df[df.B == df['C C']]
A B C C
0 1 10 10
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not isinstance(expr, str):
msg = f"expr must be a string to be evaluated, {type(expr)} given"
raise ValueError(msg)
kwargs["level"] = kwargs.pop("level", 0) + 1
kwargs["target"] = None
res = self.eval(expr, **kwargs)
try:
new_data = self.loc[res]
except ValueError:
# when res is multi-dimensional loc raises, but this is sometimes a
# valid query
new_data = self[res]
if inplace:
self._update_inplace(new_data)
else:
return new_data
def eval(self, expr, inplace=False, **kwargs):
"""
Evaluate a string describing operations on DataFrame columns.
Operates on columns only, not specific rows or elements. This allows
`eval` to run arbitrary code, which can make you vulnerable to code
injection if you pass user input to this function.
Parameters
----------
expr : str
The expression string to evaluate.
inplace : bool, default False
If the expression contains an assignment, whether to perform the
operation inplace and mutate the existing DataFrame. Otherwise,
a new DataFrame is returned.
**kwargs
See the documentation for :func:`eval` for complete details
on the keyword arguments accepted by
:meth:`~pandas.DataFrame.query`.
Returns
-------
ndarray, scalar, or pandas object
The result of the evaluation.
See Also
--------
DataFrame.query : Evaluates a boolean expression to query the columns
of a frame.
DataFrame.assign : Can evaluate an expression or function to create new
values for a column.
eval : Evaluate a Python expression as a string using various
backends.
Notes
-----
For more details see the API documentation for :func:`~eval`.
For detailed examples see :ref:`enhancing performance with eval
<enhancingperf.eval>`.
Examples
--------
>>> df = pd.DataFrame({'A': range(1, 6), 'B': range(10, 0, -2)})
>>> df
A B
0 1 10
1 2 8
2 3 6
3 4 4
4 5 2
>>> df.eval('A + B')
0 11
1 10
2 9
3 8
4 7
dtype: int64
Assignment is allowed though by default the original DataFrame is not
modified.
>>> df.eval('C = A + B')
A B C
0 1 10 11
1 2 8 10
2 3 6 9
3 4 4 8
4 5 2 7
>>> df
A B
0 1 10
1 2 8
2 3 6
3 4 4
4 5 2
Use ``inplace=True`` to modify the original DataFrame.
>>> df.eval('C = A + B', inplace=True)
>>> df
A B C
0 1 10 11
1 2 8 10
2 3 6 9
3 4 4 8
4 5 2 7
"""
from pandas.core.computation.eval import eval as _eval
inplace = validate_bool_kwarg(inplace, "inplace")
resolvers = kwargs.pop("resolvers", None)
kwargs["level"] = kwargs.pop("level", 0) + 1
if resolvers is None:
index_resolvers = self._get_index_resolvers()
column_resolvers = self._get_cleaned_column_resolvers()
resolvers = column_resolvers, index_resolvers
if "target" not in kwargs:
kwargs["target"] = self
kwargs["resolvers"] = kwargs.get("resolvers", ()) + tuple(resolvers)
return _eval(expr, inplace=inplace, **kwargs)
def select_dtypes(self, include=None, exclude=None) -> "DataFrame":
"""
Return a subset of the DataFrame's columns based on the column dtypes.
Parameters
----------
include, exclude : scalar or list-like
A selection of dtypes or strings to be included/excluded. At least
one of these parameters must be supplied.
Returns
-------
DataFrame
The subset of the frame including the dtypes in ``include`` and
excluding the dtypes in ``exclude``.
Raises
------
ValueError
* If both of ``include`` and ``exclude`` are empty
* If ``include`` and ``exclude`` have overlapping elements
* If any kind of string dtype is passed in.
Notes
-----
* To select all *numeric* types, use ``np.number`` or ``'number'``
* To select strings you must use the ``object`` dtype, but note that
this will return *all* object dtype columns
* See the `numpy dtype hierarchy
<http://docs.scipy.org/doc/numpy/reference/arrays.scalars.html>`__
* To select datetimes, use ``np.datetime64``, ``'datetime'`` or
``'datetime64'``
* To select timedeltas, use ``np.timedelta64``, ``'timedelta'`` or
``'timedelta64'``
* To select Pandas categorical dtypes, use ``'category'``
* To select Pandas datetimetz dtypes, use ``'datetimetz'`` (new in
0.20.0) or ``'datetime64[ns, tz]'``
Examples
--------
>>> df = pd.DataFrame({'a': [1, 2] * 3,
... 'b': [True, False] * 3,
... 'c': [1.0, 2.0] * 3})
>>> df
a b c
0 1 True 1.0
1 2 False 2.0
2 1 True 1.0
3 2 False 2.0
4 1 True 1.0
5 2 False 2.0
>>> df.select_dtypes(include='bool')
b
0 True
1 False
2 True
3 False
4 True
5 False
>>> df.select_dtypes(include=['float64'])
c
0 1.0
1 2.0
2 1.0
3 2.0
4 1.0
5 2.0
>>> df.select_dtypes(exclude=['int'])
b c
0 True 1.0
1 False 2.0
2 True 1.0
3 False 2.0
4 True 1.0
5 False 2.0
"""
if not is_list_like(include):
include = (include,) if include is not None else ()
if not is_list_like(exclude):
exclude = (exclude,) if exclude is not None else ()
selection = (frozenset(include), frozenset(exclude))
if not any(selection):
raise ValueError("at least one of include or exclude must be nonempty")
# convert the myriad valid dtypes object to a single representation
include = frozenset(infer_dtype_from_object(x) for x in include)
exclude = frozenset(infer_dtype_from_object(x) for x in exclude)
for dtypes in (include, exclude):
invalidate_string_dtypes(dtypes)
# can't both include AND exclude!
if not include.isdisjoint(exclude):
raise ValueError(f"include and exclude overlap on {(include & exclude)}")
# We raise when both include and exclude are empty
# Hence, we can just shrink the columns we want to keep
keep_these = np.full(self.shape[1], True)
def extract_unique_dtypes_from_dtypes_set(
dtypes_set: FrozenSet[Dtype], unique_dtypes: np.ndarray
) -> List[Dtype]:
extracted_dtypes = [
unique_dtype
for unique_dtype in unique_dtypes
if issubclass(unique_dtype.type, tuple(dtypes_set)) # type: ignore
]
return extracted_dtypes
unique_dtypes = self.dtypes.unique()
if include:
included_dtypes = extract_unique_dtypes_from_dtypes_set(
include, unique_dtypes
)
keep_these &= self.dtypes.isin(included_dtypes)
if exclude:
excluded_dtypes = extract_unique_dtypes_from_dtypes_set(
exclude, unique_dtypes
)
keep_these &= ~self.dtypes.isin(excluded_dtypes)
return self.iloc[:, keep_these.values]
def insert(self, loc, column, value, allow_duplicates=False) -> None:
"""
Insert column into DataFrame at specified location.
Raises a ValueError if `column` is already contained in the DataFrame,
unless `allow_duplicates` is set to True.
Parameters
----------
loc : int
Insertion index. Must verify 0 <= loc <= len(columns).
column : str, number, or hashable object
Label of the inserted column.
value : int, Series, or array-like
allow_duplicates : bool, optional
"""
self._ensure_valid_index(value)
value = self._sanitize_column(column, value, broadcast=False)
self._data.insert(loc, column, value, allow_duplicates=allow_duplicates)
def assign(self, **kwargs) -> "DataFrame":
r"""
Assign new columns to a DataFrame.
Returns a new object with all original columns in addition to new ones.
Existing columns that are re-assigned will be overwritten.
Parameters
----------
**kwargs : dict of {str: callable or Series}
The column names are keywords. If the values are
callable, they are computed on the DataFrame and
assigned to the new columns. The callable must not
change input DataFrame (though pandas doesn't check it).
If the values are not callable, (e.g. a Series, scalar, or array),
they are simply assigned.
Returns
-------
DataFrame
A new DataFrame with the new columns in addition to
all the existing columns.
Notes
-----
Assigning multiple columns within the same ``assign`` is possible.
Later items in '\*\*kwargs' may refer to newly created or modified
columns in 'df'; items are computed and assigned into 'df' in order.
.. versionchanged:: 0.23.0
Keyword argument order is maintained.
Examples
--------
>>> df = pd.DataFrame({'temp_c': [17.0, 25.0]},
... index=['Portland', 'Berkeley'])
>>> df
temp_c
Portland 17.0
Berkeley 25.0
Where the value is a callable, evaluated on `df`:
>>> df.assign(temp_f=lambda x: x.temp_c * 9 / 5 + 32)
temp_c temp_f
Portland 17.0 62.6
Berkeley 25.0 77.0
Alternatively, the same behavior can be achieved by directly
referencing an existing Series or sequence:
>>> df.assign(temp_f=df['temp_c'] * 9 / 5 + 32)
temp_c temp_f
Portland 17.0 62.6
Berkeley 25.0 77.0
You can create multiple columns within the same assign where one
of the columns depends on another one defined within the same assign:
>>> df.assign(temp_f=lambda x: x['temp_c'] * 9 / 5 + 32,
... temp_k=lambda x: (x['temp_f'] + 459.67) * 5 / 9)
temp_c temp_f temp_k
Portland 17.0 62.6 290.15
Berkeley 25.0 77.0 298.15
"""
data = self.copy()
for k, v in kwargs.items():
data[k] = com.apply_if_callable(v, data)
return data
def _sanitize_column(self, key, value, broadcast=True):
"""
Ensures new columns (which go into the BlockManager as new blocks) are
always copied and converted into an array.
Parameters
----------
key : object
value : scalar, Series, or array-like
broadcast : bool, default True
If ``key`` matches multiple duplicate column names in the
DataFrame, this parameter indicates whether ``value`` should be
tiled so that the returned array contains a (duplicated) column for
each occurrence of the key. If False, ``value`` will not be tiled.
Returns
-------
numpy.ndarray
"""
def reindexer(value):
# reindex if necessary
if value.index.equals(self.index) or not len(self.index):
value = value._values.copy()
else:
# GH 4107
try:
value = value.reindex(self.index)._values
except ValueError as err:
# raised in MultiIndex.from_tuples, see test_insert_error_msmgs
if not value.index.is_unique:
# duplicate axis
raise err
# other
raise TypeError(
"incompatible index of inserted column with frame index"
)
return value
if isinstance(value, Series):
value = reindexer(value)
elif isinstance(value, DataFrame):
# align right-hand-side columns if self.columns
# is multi-index and self[key] is a sub-frame
if isinstance(self.columns, ABCMultiIndex) and key in self.columns:
loc = self.columns.get_loc(key)
if isinstance(loc, (slice, Series, np.ndarray, Index)):
cols = maybe_droplevels(self.columns[loc], key)
if len(cols) and not cols.equals(value.columns):
value = value.reindex(cols, axis=1)
# now align rows
value = reindexer(value).T
elif isinstance(value, ExtensionArray):
# Explicitly copy here, instead of in sanitize_index,
# as sanitize_index won't copy an EA, even with copy=True
value = value.copy()
value = sanitize_index(value, self.index)
elif isinstance(value, Index) or is_sequence(value):
# turn me into an ndarray
value = sanitize_index(value, self.index)
if not isinstance(value, (np.ndarray, Index)):
if isinstance(value, list) and len(value) > 0:
value = maybe_convert_platform(value)
else:
value = com.asarray_tuplesafe(value)
elif value.ndim == 2:
value = value.copy().T
elif isinstance(value, Index):
value = value.copy(deep=True)
else:
value = value.copy()
# possibly infer to datetimelike
if is_object_dtype(value.dtype):
value = maybe_infer_to_datetimelike(value)
else:
# cast ignores pandas dtypes. so save the dtype first
infer_dtype, _ = infer_dtype_from_scalar(value, pandas_dtype=True)
# upcast
value = cast_scalar_to_array(len(self.index), value)
value = maybe_cast_to_datetime(value, infer_dtype)
# return internal types directly
if is_extension_array_dtype(value):
return value
# broadcast across multiple columns if necessary
if broadcast and key in self.columns and value.ndim == 1:
if not self.columns.is_unique or isinstance(self.columns, ABCMultiIndex):
existing_piece = self[key]
if isinstance(existing_piece, DataFrame):
value = np.tile(value, (len(existing_piece.columns), 1))
return np.atleast_2d(np.asarray(value))
@property
def _series(self):
return {
item: Series(self._data.iget(idx), index=self.index, name=item)
for idx, item in enumerate(self.columns)
}
def lookup(self, row_labels, col_labels) -> np.ndarray:
"""
Label-based "fancy indexing" function for DataFrame.
Given equal-length arrays of row and column labels, return an
array of the values corresponding to each (row, col) pair.
Parameters
----------
row_labels : sequence
The row labels to use for lookup.
col_labels : sequence
The column labels to use for lookup.
Returns
-------
numpy.ndarray
The found values.
"""
n = len(row_labels)
if n != len(col_labels):
raise ValueError("Row labels must have same size as column labels")
thresh = 1000
if not self._is_mixed_type or n > thresh:
values = self.values
ridx = self.index.get_indexer(row_labels)
cidx = self.columns.get_indexer(col_labels)
if (ridx == -1).any():
raise KeyError("One or more row labels was not found")
if (cidx == -1).any():
raise KeyError("One or more column labels was not found")
flat_index = ridx * len(self.columns) + cidx
result = values.flat[flat_index]
else:
result = np.empty(n, dtype="O")
for i, (r, c) in enumerate(zip(row_labels, col_labels)):
result[i] = self._get_value(r, c)
if is_object_dtype(result):
result = lib.maybe_convert_objects(result)
return result
# ----------------------------------------------------------------------
# Reindexing and alignment
def _reindex_axes(self, axes, level, limit, tolerance, method, fill_value, copy):
frame = self
columns = axes["columns"]
if columns is not None:
frame = frame._reindex_columns(
columns, method, copy, level, fill_value, limit, tolerance
)
index = axes["index"]
if index is not None:
frame = frame._reindex_index(
index, method, copy, level, fill_value, limit, tolerance
)
return frame
def _reindex_index(
self,
new_index,
method,
copy,
level,
fill_value=np.nan,
limit=None,
tolerance=None,
):
new_index, indexer = self.index.reindex(
new_index, method=method, level=level, limit=limit, tolerance=tolerance
)
return self._reindex_with_indexers(
{0: [new_index, indexer]},
copy=copy,
fill_value=fill_value,
allow_dups=False,
)
def _reindex_columns(
self,
new_columns,
method,
copy,
level,
fill_value=None,
limit=None,
tolerance=None,
):
new_columns, indexer = self.columns.reindex(
new_columns, method=method, level=level, limit=limit, tolerance=tolerance
)
return self._reindex_with_indexers(
{1: [new_columns, indexer]},
copy=copy,
fill_value=fill_value,
allow_dups=False,
)
def _reindex_multi(self, axes, copy, fill_value) -> "DataFrame":
"""
We are guaranteed non-Nones in the axes.
"""
new_index, row_indexer = self.index.reindex(axes["index"])
new_columns, col_indexer = self.columns.reindex(axes["columns"])
if row_indexer is not None and col_indexer is not None:
indexer = row_indexer, col_indexer
new_values = algorithms.take_2d_multi(
self.values, indexer, fill_value=fill_value
)
return self._constructor(new_values, index=new_index, columns=new_columns)
else:
return self._reindex_with_indexers(
{0: [new_index, row_indexer], 1: [new_columns, col_indexer]},
copy=copy,
fill_value=fill_value,
)
@Appender(_shared_docs["align"] % _shared_doc_kwargs)
def align(
self,
other,
join="outer",
axis=None,
level=None,
copy=True,
fill_value=None,
method=None,
limit=None,
fill_axis=0,
broadcast_axis=None,
) -> "DataFrame":
return super().align(
other,
join=join,
axis=axis,
level=level,
copy=copy,
fill_value=fill_value,
method=method,
limit=limit,
fill_axis=fill_axis,
broadcast_axis=broadcast_axis,
)
@Appender(
"""
>>> df = pd.DataFrame({"A": [1, 2, 3], "B": [4, 5, 6]})
Change the row labels.
>>> df.set_axis(['a', 'b', 'c'], axis='index')
A B
a 1 4
b 2 5
c 3 6
Change the column labels.
>>> df.set_axis(['I', 'II'], axis='columns')
I II
0 1 4
1 2 5
2 3 6
Now, update the labels inplace.
>>> df.set_axis(['i', 'ii'], axis='columns', inplace=True)
>>> df
i ii
0 1 4
1 2 5
2 3 6
"""
)
@Substitution(
**_shared_doc_kwargs,
extended_summary_sub=" column or",
axis_description_sub=", and 1 identifies the columns",
see_also_sub=" or columns",
)
@Appender(NDFrame.set_axis.__doc__)
def set_axis(self, labels, axis=0, inplace=False):
return super().set_axis(labels, axis=axis, inplace=inplace)
@Substitution(**_shared_doc_kwargs)
@Appender(NDFrame.reindex.__doc__)
@rewrite_axis_style_signature(
"labels",
[
("method", None),
("copy", True),
("level", None),
("fill_value", np.nan),
("limit", None),
("tolerance", None),
],
)
def reindex(self, *args, **kwargs) -> "DataFrame":
axes = validate_axis_style_args(self, args, kwargs, "labels", "reindex")
kwargs.update(axes)
# Pop these, since the values are in `kwargs` under different names
kwargs.pop("axis", None)
kwargs.pop("labels", None)
return self._ensure_type(super().reindex(**kwargs))
def drop(
self,
labels=None,
axis=0,
index=None,
columns=None,
level=None,
inplace=False,
errors="raise",
):
"""
Drop specified labels from rows or columns.
Remove rows or columns by specifying label names and corresponding
axis, or by specifying directly index or column names. When using a
multi-index, labels on different levels can be removed by specifying
the level.
Parameters
----------
labels : single label or list-like
Index or column labels to drop.
axis : {0 or 'index', 1 or 'columns'}, default 0
Whether to drop labels from the index (0 or 'index') or
columns (1 or 'columns').
index : single label or list-like
Alternative to specifying axis (``labels, axis=0``
is equivalent to ``index=labels``).
.. versionadded:: 0.21.0
columns : single label or list-like
Alternative to specifying axis (``labels, axis=1``
is equivalent to ``columns=labels``).
.. versionadded:: 0.21.0
level : int or level name, optional
For MultiIndex, level from which the labels will be removed.
inplace : bool, default False
If True, do operation inplace and return None.
errors : {'ignore', 'raise'}, default 'raise'
If 'ignore', suppress error and only existing labels are
dropped.
Returns
-------
DataFrame
DataFrame without the removed index or column labels.
Raises
------
KeyError
If any of the labels is not found in the selected axis.
See Also
--------
DataFrame.loc : Label-location based indexer for selection by label.
DataFrame.dropna : Return DataFrame with labels on given axis omitted
where (all or any) data are missing.
DataFrame.drop_duplicates : Return DataFrame with duplicate rows
removed, optionally only considering certain columns.
Series.drop : Return Series with specified index labels removed.
Examples
--------
>>> df = pd.DataFrame(np.arange(12).reshape(3, 4),
... columns=['A', 'B', 'C', 'D'])
>>> df
A B C D
0 0 1 2 3
1 4 5 6 7
2 8 9 10 11
Drop columns
>>> df.drop(['B', 'C'], axis=1)
A D
0 0 3
1 4 7
2 8 11
>>> df.drop(columns=['B', 'C'])
A D
0 0 3
1 4 7
2 8 11
Drop a row by index
>>> df.drop([0, 1])
A B C D
2 8 9 10 11
Drop columns and/or rows of MultiIndex DataFrame
>>> midx = pd.MultiIndex(levels=[['lama', 'cow', 'falcon'],
... ['speed', 'weight', 'length']],
... codes=[[0, 0, 0, 1, 1, 1, 2, 2, 2],
... [0, 1, 2, 0, 1, 2, 0, 1, 2]])
>>> df = pd.DataFrame(index=midx, columns=['big', 'small'],
... data=[[45, 30], [200, 100], [1.5, 1], [30, 20],
... [250, 150], [1.5, 0.8], [320, 250],
... [1, 0.8], [0.3, 0.2]])
>>> df
big small
lama speed 45.0 30.0
weight 200.0 100.0
length 1.5 1.0
cow speed 30.0 20.0
weight 250.0 150.0
length 1.5 0.8
falcon speed 320.0 250.0
weight 1.0 0.8
length 0.3 0.2
>>> df.drop(index='cow', columns='small')
big
lama speed 45.0
weight 200.0
length 1.5
falcon speed 320.0
weight 1.0
length 0.3
>>> df.drop(index='length', level=1)
big small
lama speed 45.0 30.0
weight 200.0 100.0
cow speed 30.0 20.0
weight 250.0 150.0
falcon speed 320.0 250.0
weight 1.0 0.8
"""
return super().drop(
labels=labels,
axis=axis,
index=index,
columns=columns,
level=level,
inplace=inplace,
errors=errors,
)
@rewrite_axis_style_signature(
"mapper",
[("copy", True), ("inplace", False), ("level", None), ("errors", "ignore")],
)
def rename(
self,
mapper: Optional[Renamer] = None,
*,
index: Optional[Renamer] = None,
columns: Optional[Renamer] = None,
axis: Optional[Axis] = None,
copy: bool = True,
inplace: bool = False,
level: Optional[Level] = None,
errors: str = "ignore",
) -> Optional["DataFrame"]:
"""
Alter axes labels.
Function / dict values must be unique (1-to-1). Labels not contained in
a dict / Series will be left as-is. Extra labels listed don't throw an
error.
See the :ref:`user guide <basics.rename>` for more.
Parameters
----------
mapper : dict-like or function
Dict-like or functions transformations to apply to
that axis' values. Use either ``mapper`` and ``axis`` to
specify the axis to target with ``mapper``, or ``index`` and
``columns``.
index : dict-like or function
Alternative to specifying axis (``mapper, axis=0``
is equivalent to ``index=mapper``).
columns : dict-like or function
Alternative to specifying axis (``mapper, axis=1``
is equivalent to ``columns=mapper``).
axis : int or str
Axis to target with ``mapper``. Can be either the axis name
('index', 'columns') or number (0, 1). The default is 'index'.
copy : bool, default True
Also copy underlying data.
inplace : bool, default False
Whether to return a new DataFrame. If True then value of copy is
ignored.
level : int or level name, default None
In case of a MultiIndex, only rename labels in the specified
level.
errors : {'ignore', 'raise'}, default 'ignore'
If 'raise', raise a `KeyError` when a dict-like `mapper`, `index`,
or `columns` contains labels that are not present in the Index
being transformed.
If 'ignore', existing keys will be renamed and extra keys will be
ignored.
Returns
-------
DataFrame
DataFrame with the renamed axis labels.
Raises
------
KeyError
If any of the labels is not found in the selected axis and
"errors='raise'".
See Also
--------
DataFrame.rename_axis : Set the name of the axis.
Examples
--------
``DataFrame.rename`` supports two calling conventions
* ``(index=index_mapper, columns=columns_mapper, ...)``
* ``(mapper, axis={'index', 'columns'}, ...)``
We *highly* recommend using keyword arguments to clarify your
intent.
Rename columns using a mapping:
>>> df = pd.DataFrame({"A": [1, 2, 3], "B": [4, 5, 6]})
>>> df.rename(columns={"A": "a", "B": "c"})
a c
0 1 4
1 2 5
2 3 6
Rename index using a mapping:
>>> df.rename(index={0: "x", 1: "y", 2: "z"})
A B
x 1 4
y 2 5
z 3 6
Cast index labels to a different type:
>>> df.index
RangeIndex(start=0, stop=3, step=1)
>>> df.rename(index=str).index
Index(['0', '1', '2'], dtype='object')
>>> df.rename(columns={"A": "a", "B": "b", "C": "c"}, errors="raise")
Traceback (most recent call last):
KeyError: ['C'] not found in axis
Using axis-style parameters
>>> df.rename(str.lower, axis='columns')
a b
0 1 4
1 2 5
2 3 6
>>> df.rename({1: 2, 2: 4}, axis='index')
A B
0 1 4
2 2 5
4 3 6
"""
return super().rename(
mapper=mapper,
index=index,
columns=columns,
axis=axis,
copy=copy,
inplace=inplace,
level=level,
errors=errors,
)
@Substitution(**_shared_doc_kwargs)
@Appender(NDFrame.fillna.__doc__)
def fillna(
self,
value=None,
method=None,
axis=None,
inplace=False,
limit=None,
downcast=None,
) -> Optional["DataFrame"]:
return super().fillna(
value=value,
method=method,
axis=axis,
inplace=inplace,
limit=limit,
downcast=downcast,
)
@Appender(_shared_docs["replace"] % _shared_doc_kwargs)
def replace(
self,
to_replace=None,
value=None,
inplace=False,
limit=None,
regex=False,
method="pad",
):
return super().replace(
to_replace=to_replace,
value=value,
inplace=inplace,
limit=limit,
regex=regex,
method=method,
)
@Appender(_shared_docs["shift"] % _shared_doc_kwargs)
def shift(self, periods=1, freq=None, axis=0, fill_value=None) -> "DataFrame":
return self._ensure_type(
super().shift(periods=periods, freq=freq, axis=axis, fill_value=fill_value)
)
def set_index(
self, keys, drop=True, append=False, inplace=False, verify_integrity=False
):
"""
Set the DataFrame index using existing columns.
Set the DataFrame index (row labels) using one or more existing
columns or arrays (of the correct length). The index can replace the
existing index or expand on it.
Parameters
----------
keys : label or array-like or list of labels/arrays
This parameter can be either a single column key, a single array of
the same length as the calling DataFrame, or a list containing an
arbitrary combination of column keys and arrays. Here, "array"
encompasses :class:`Series`, :class:`Index`, ``np.ndarray``, and
instances of :class:`~collections.abc.Iterator`.
drop : bool, default True
Delete columns to be used as the new index.
append : bool, default False
Whether to append columns to existing index.
inplace : bool, default False
Modify the DataFrame in place (do not create a new object).
verify_integrity : bool, default False
Check the new index for duplicates. Otherwise defer the check until
necessary. Setting to False will improve the performance of this
method.
Returns
-------
DataFrame
Changed row labels.
See Also
--------
DataFrame.reset_index : Opposite of set_index.
DataFrame.reindex : Change to new indices or expand indices.
DataFrame.reindex_like : Change to same indices as other DataFrame.
Examples
--------
>>> df = pd.DataFrame({'month': [1, 4, 7, 10],
... 'year': [2012, 2014, 2013, 2014],
... 'sale': [55, 40, 84, 31]})
>>> df
month year sale
0 1 2012 55
1 4 2014 40
2 7 2013 84
3 10 2014 31
Set the index to become the 'month' column:
>>> df.set_index('month')
year sale
month
1 2012 55
4 2014 40
7 2013 84
10 2014 31
Create a MultiIndex using columns 'year' and 'month':
>>> df.set_index(['year', 'month'])
sale
year month
2012 1 55
2014 4 40
2013 7 84
2014 10 31
Create a MultiIndex using an Index and a column:
>>> df.set_index([pd.Index([1, 2, 3, 4]), 'year'])
month sale
year
1 2012 1 55
2 2014 4 40
3 2013 7 84
4 2014 10 31
Create a MultiIndex using two Series:
>>> s = pd.Series([1, 2, 3, 4])
>>> df.set_index([s, s**2])
month year sale
1 1 1 2012 55
2 4 4 2014 40
3 9 7 2013 84
4 16 10 2014 31
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not isinstance(keys, list):
keys = [keys]
err_msg = (
'The parameter "keys" may be a column key, one-dimensional '
"array, or a list containing only valid column keys and "
"one-dimensional arrays."
)
missing: List[Optional[Hashable]] = []
for col in keys:
if isinstance(
col, (ABCIndexClass, ABCSeries, np.ndarray, list, abc.Iterator)
):
# arrays are fine as long as they are one-dimensional
# iterators get converted to list below
if getattr(col, "ndim", 1) != 1:
raise ValueError(err_msg)
else:
# everything else gets tried as a key; see GH 24969
try:
found = col in self.columns
except TypeError:
raise TypeError(f"{err_msg}. Received column of type {type(col)}")
else:
if not found:
missing.append(col)
if missing:
raise KeyError(f"None of {missing} are in the columns")
if inplace:
frame = self
else:
frame = self.copy()
arrays = []
names = []
if append:
names = list(self.index.names)
if isinstance(self.index, ABCMultiIndex):
for i in range(self.index.nlevels):
arrays.append(self.index._get_level_values(i))
else:
arrays.append(self.index)
to_remove: List[Optional[Hashable]] = []
for col in keys:
if isinstance(col, ABCMultiIndex):
for n in range(col.nlevels):
arrays.append(col._get_level_values(n))
names.extend(col.names)
elif isinstance(col, (ABCIndexClass, ABCSeries)):
# if Index then not MultiIndex (treated above)
arrays.append(col)
names.append(col.name)
elif isinstance(col, (list, np.ndarray)):
arrays.append(col)
names.append(None)
elif isinstance(col, abc.Iterator):
arrays.append(list(col))
names.append(None)
# from here, col can only be a column label
else:
arrays.append(frame[col]._values)
names.append(col)
if drop:
to_remove.append(col)
if len(arrays[-1]) != len(self):
# check newest element against length of calling frame, since
# ensure_index_from_sequences would not raise for append=False.
raise ValueError(
f"Length mismatch: Expected {len(self)} rows, "
f"received array of length {len(arrays[-1])}"
)
index = ensure_index_from_sequences(arrays, names)
if verify_integrity and not index.is_unique:
duplicates = index[index.duplicated()].unique()
raise ValueError(f"Index has duplicate keys: {duplicates}")
# use set to handle duplicate column names gracefully in case of drop
for c in set(to_remove):
del frame[c]
# clear up memory usage
index._cleanup()
frame.index = index
if not inplace:
return frame
def reset_index(
self,
level: Optional[Union[Hashable, Sequence[Hashable]]] = None,
drop: bool = False,
inplace: bool = False,
col_level: Hashable = 0,
col_fill: Optional[Hashable] = "",
) -> Optional["DataFrame"]:
"""
Reset the index, or a level of it.
Reset the index of the DataFrame, and use the default one instead.
If the DataFrame has a MultiIndex, this method can remove one or more
levels.
Parameters
----------
level : int, str, tuple, or list, default None
Only remove the given levels from the index. Removes all levels by
default.
drop : bool, default False
Do not try to insert index into dataframe columns. This resets
the index to the default integer index.
inplace : bool, default False
Modify the DataFrame in place (do not create a new object).
col_level : int or str, default 0
If the columns have multiple levels, determines which level the
labels are inserted into. By default it is inserted into the first
level.
col_fill : object, default ''
If the columns have multiple levels, determines how the other
levels are named. If None then the index name is repeated.
Returns
-------
DataFrame or None
DataFrame with the new index or None if ``inplace=True``.
See Also
--------
DataFrame.set_index : Opposite of reset_index.
DataFrame.reindex : Change to new indices or expand indices.
DataFrame.reindex_like : Change to same indices as other DataFrame.
Examples
--------
>>> df = pd.DataFrame([('bird', 389.0),
... ('bird', 24.0),
... ('mammal', 80.5),
... ('mammal', np.nan)],
... index=['falcon', 'parrot', 'lion', 'monkey'],
... columns=('class', 'max_speed'))
>>> df
class max_speed
falcon bird 389.0
parrot bird 24.0
lion mammal 80.5
monkey mammal NaN
When we reset the index, the old index is added as a column, and a
new sequential index is used:
>>> df.reset_index()
index class max_speed
0 falcon bird 389.0
1 parrot bird 24.0
2 lion mammal 80.5
3 monkey mammal NaN
We can use the `drop` parameter to avoid the old index being added as
a column:
>>> df.reset_index(drop=True)
class max_speed
0 bird 389.0
1 bird 24.0
2 mammal 80.5
3 mammal NaN
You can also use `reset_index` with `MultiIndex`.
>>> index = pd.MultiIndex.from_tuples([('bird', 'falcon'),
... ('bird', 'parrot'),
... ('mammal', 'lion'),
... ('mammal', 'monkey')],
... names=['class', 'name'])
>>> columns = pd.MultiIndex.from_tuples([('speed', 'max'),
... ('species', 'type')])
>>> df = pd.DataFrame([(389.0, 'fly'),
... ( 24.0, 'fly'),
... ( 80.5, 'run'),
... (np.nan, 'jump')],
... index=index,
... columns=columns)
>>> df
speed species
max type
class name
bird falcon 389.0 fly
parrot 24.0 fly
mammal lion 80.5 run
monkey NaN jump
If the index has multiple levels, we can reset a subset of them:
>>> df.reset_index(level='class')
class speed species
max type
name
falcon bird 389.0 fly
parrot bird 24.0 fly
lion mammal 80.5 run
monkey mammal NaN jump
If we are not dropping the index, by default, it is placed in the top
level. We can place it in another level:
>>> df.reset_index(level='class', col_level=1)
speed species
class max type
name
falcon bird 389.0 fly
parrot bird 24.0 fly
lion mammal 80.5 run
monkey mammal NaN jump
When the index is inserted under another level, we can specify under
which one with the parameter `col_fill`:
>>> df.reset_index(level='class', col_level=1, col_fill='species')
species speed species
class max type
name
falcon bird 389.0 fly
parrot bird 24.0 fly
lion mammal 80.5 run
monkey mammal NaN jump
If we specify a nonexistent level for `col_fill`, it is created:
>>> df.reset_index(level='class', col_level=1, col_fill='genus')
genus speed species
class max type
name
falcon bird 389.0 fly
parrot bird 24.0 fly
lion mammal 80.5 run
monkey mammal NaN jump
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if inplace:
new_obj = self
else:
new_obj = self.copy()
def _maybe_casted_values(index, labels=None):
values = index._values
if not isinstance(index, (PeriodIndex, DatetimeIndex)):
if values.dtype == np.object_:
values = lib.maybe_convert_objects(values)
# if we have the labels, extract the values with a mask
if labels is not None:
mask = labels == -1
# we can have situations where the whole mask is -1,
# meaning there is nothing found in labels, so make all nan's
if mask.all():
values = np.empty(len(mask))
values.fill(np.nan)
else:
values = values.take(labels)
# TODO(https://github.com/pandas-dev/pandas/issues/24206)
# Push this into maybe_upcast_putmask?
# We can't pass EAs there right now. Looks a bit
# complicated.
# So we unbox the ndarray_values, op, re-box.
values_type = type(values)
values_dtype = values.dtype
if issubclass(values_type, DatetimeLikeArray):
values = values._data
if mask.any():
values, _ = maybe_upcast_putmask(values, mask, np.nan)
if issubclass(values_type, DatetimeLikeArray):
values = values_type(values, dtype=values_dtype)
return values
new_index = ibase.default_index(len(new_obj))
if level is not None:
if not isinstance(level, (tuple, list)):
level = [level]
level = [self.index._get_level_number(lev) for lev in level]
if len(level) < self.index.nlevels:
new_index = self.index.droplevel(level)
if not drop:
to_insert: Iterable[Tuple[Any, Optional[Any]]]
if isinstance(self.index, ABCMultiIndex):
names = [
(n if n is not None else f"level_{i}")
for i, n in enumerate(self.index.names)
]
to_insert = zip(self.index.levels, self.index.codes)
else:
default = "index" if "index" not in self else "level_0"
names = [default] if self.index.name is None else [self.index.name]
to_insert = ((self.index, None),)
multi_col = isinstance(self.columns, ABCMultiIndex)
for i, (lev, lab) in reversed(list(enumerate(to_insert))):
if not (level is None or i in level):
continue
name = names[i]
if multi_col:
col_name = list(name) if isinstance(name, tuple) else [name]
if col_fill is None:
if len(col_name) not in (1, self.columns.nlevels):
raise ValueError(
"col_fill=None is incompatible "
f"with incomplete column name {name}"
)
col_fill = col_name[0]
lev_num = self.columns._get_level_number(col_level)
name_lst = [col_fill] * lev_num + col_name
missing = self.columns.nlevels - len(name_lst)
name_lst += [col_fill] * missing
name = tuple(name_lst)
# to ndarray and maybe infer different dtype
level_values = _maybe_casted_values(lev, lab)
new_obj.insert(0, name, level_values)
new_obj.index = new_index
if not inplace:
return new_obj
return None
# ----------------------------------------------------------------------
# Reindex-based selection methods
@Appender(_shared_docs["isna"] % _shared_doc_kwargs)
def isna(self) -> "DataFrame":
return super().isna()
@Appender(_shared_docs["isna"] % _shared_doc_kwargs)
def isnull(self) -> "DataFrame":
return super().isnull()
@Appender(_shared_docs["notna"] % _shared_doc_kwargs)
def notna(self) -> "DataFrame":
return super().notna()
@Appender(_shared_docs["notna"] % _shared_doc_kwargs)
def notnull(self) -> "DataFrame":
return super().notnull()
def dropna(self, axis=0, how="any", thresh=None, subset=None, inplace=False):
"""
Remove missing values.
See the :ref:`User Guide <missing_data>` for more on which values are
considered missing, and how to work with missing data.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
Determine if rows or columns which contain missing values are
removed.
* 0, or 'index' : Drop rows which contain missing values.
* 1, or 'columns' : Drop columns which contain missing value.
.. versionchanged:: 1.0.0
Pass tuple or list to drop on multiple axes.
Only a single axis is allowed.
how : {'any', 'all'}, default 'any'
Determine if row or column is removed from DataFrame, when we have
at least one NA or all NA.
* 'any' : If any NA values are present, drop that row or column.
* 'all' : If all values are NA, drop that row or column.
thresh : int, optional
Require that many non-NA values.
subset : array-like, optional
Labels along other axis to consider, e.g. if you are dropping rows
these would be a list of columns to include.
inplace : bool, default False
If True, do operation inplace and return None.
Returns
-------
DataFrame
DataFrame with NA entries dropped from it.
See Also
--------
DataFrame.isna: Indicate missing values.
DataFrame.notna : Indicate existing (non-missing) values.
DataFrame.fillna : Replace missing values.
Series.dropna : Drop missing values.
Index.dropna : Drop missing indices.
Examples
--------
>>> df = pd.DataFrame({"name": ['Alfred', 'Batman', 'Catwoman'],
... "toy": [np.nan, 'Batmobile', 'Bullwhip'],
... "born": [pd.NaT, pd.Timestamp("1940-04-25"),
... pd.NaT]})
>>> df
name toy born
0 Alfred NaN NaT
1 Batman Batmobile 1940-04-25
2 Catwoman Bullwhip NaT
Drop the rows where at least one element is missing.
>>> df.dropna()
name toy born
1 Batman Batmobile 1940-04-25
Drop the columns where at least one element is missing.
>>> df.dropna(axis='columns')
name
0 Alfred
1 Batman
2 Catwoman
Drop the rows where all elements are missing.
>>> df.dropna(how='all')
name toy born
0 Alfred NaN NaT
1 Batman Batmobile 1940-04-25
2 Catwoman Bullwhip NaT
Keep only the rows with at least 2 non-NA values.
>>> df.dropna(thresh=2)
name toy born
1 Batman Batmobile 1940-04-25
2 Catwoman Bullwhip NaT
Define in which columns to look for missing values.
>>> df.dropna(subset=['name', 'born'])
name toy born
1 Batman Batmobile 1940-04-25
Keep the DataFrame with valid entries in the same variable.
>>> df.dropna(inplace=True)
>>> df
name toy born
1 Batman Batmobile 1940-04-25
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if isinstance(axis, (tuple, list)):
# GH20987
raise TypeError("supplying multiple axes to axis is no longer supported.")
axis = self._get_axis_number(axis)
agg_axis = 1 - axis
agg_obj = self
if subset is not None:
ax = self._get_axis(agg_axis)
indices = ax.get_indexer_for(subset)
check = indices == -1
if check.any():
raise KeyError(list(np.compress(check, subset)))
agg_obj = self.take(indices, axis=agg_axis)
count = agg_obj.count(axis=agg_axis)
if thresh is not None:
mask = count >= thresh
elif how == "any":
mask = count == len(agg_obj._get_axis(agg_axis))
elif how == "all":
mask = count > 0
else:
if how is not None:
raise ValueError(f"invalid how option: {how}")
else:
raise TypeError("must specify how or thresh")
result = self.loc(axis=axis)[mask]
if inplace:
self._update_inplace(result)
else:
return result
def drop_duplicates(
self,
subset: Optional[Union[Hashable, Sequence[Hashable]]] = None,
keep: Union[str, bool] = "first",
inplace: bool = False,
ignore_index: bool = False,
) -> Optional["DataFrame"]:
"""
Return DataFrame with duplicate rows removed.
Considering certain columns is optional. Indexes, including time indexes
are ignored.
Parameters
----------
subset : column label or sequence of labels, optional
Only consider certain columns for identifying duplicates, by
default use all of the columns.
keep : {'first', 'last', False}, default 'first'
Determines which duplicates (if any) to keep.
- ``first`` : Drop duplicates except for the first occurrence.
- ``last`` : Drop duplicates except for the last occurrence.
- False : Drop all duplicates.
inplace : bool, default False
Whether to drop duplicates in place or to return a copy.
ignore_index : bool, default False
If True, the resulting axis will be labeled 0, 1, …, n - 1.
.. versionadded:: 1.0.0
Returns
-------
DataFrame
DataFrame with duplicates removed or None if ``inplace=True``.
"""
if self.empty:
return self.copy()
inplace = validate_bool_kwarg(inplace, "inplace")
duplicated = self.duplicated(subset, keep=keep)
if inplace:
(inds,) = (-duplicated)._ndarray_values.nonzero()
new_data = self._data.take(inds)
if ignore_index:
new_data.axes[1] = ibase.default_index(len(inds))
self._update_inplace(new_data)
else:
result = self[-duplicated]
if ignore_index:
result.index = ibase.default_index(len(result))
return result
return None
def duplicated(
self,
subset: Optional[Union[Hashable, Sequence[Hashable]]] = None,
keep: Union[str, bool] = "first",
) -> "Series":
"""
Return boolean Series denoting duplicate rows.
Considering certain columns is optional.
Parameters
----------
subset : column label or sequence of labels, optional
Only consider certain columns for identifying duplicates, by
default use all of the columns.
keep : {'first', 'last', False}, default 'first'
Determines which duplicates (if any) to mark.
- ``first`` : Mark duplicates as ``True`` except for the first occurrence.
- ``last`` : Mark duplicates as ``True`` except for the last occurrence.
- False : Mark all duplicates as ``True``.
Returns
-------
Series
"""
from pandas.core.sorting import get_group_index
from pandas._libs.hashtable import duplicated_int64, _SIZE_HINT_LIMIT
if self.empty:
return Series(dtype=bool)
def f(vals):
labels, shape = algorithms.factorize(
vals, size_hint=min(len(self), _SIZE_HINT_LIMIT)
)
return labels.astype("i8", copy=False), len(shape)
if subset is None:
subset = self.columns
elif (
not np.iterable(subset)
or isinstance(subset, str)
or isinstance(subset, tuple)
and subset in self.columns
):
subset = (subset,)
# needed for mypy since can't narrow types using np.iterable
subset = cast(Iterable, subset)
# Verify all columns in subset exist in the queried dataframe
# Otherwise, raise a KeyError, same as if you try to __getitem__ with a
# key that doesn't exist.
diff = Index(subset).difference(self.columns)
if not diff.empty:
raise KeyError(diff)
vals = (col.values for name, col in self.items() if name in subset)
labels, shape = map(list, zip(*map(f, vals)))
ids = get_group_index(labels, shape, sort=False, xnull=False)
return Series(duplicated_int64(ids, keep), index=self.index)
# ----------------------------------------------------------------------
# Sorting
@Substitution(**_shared_doc_kwargs)
@Appender(NDFrame.sort_values.__doc__)
def sort_values(
self,
by,
axis=0,
ascending=True,
inplace=False,
kind="quicksort",
na_position="last",
ignore_index=False,
):
inplace = validate_bool_kwarg(inplace, "inplace")
axis = self._get_axis_number(axis)
if not isinstance(by, list):
by = [by]
if is_sequence(ascending) and len(by) != len(ascending):
raise ValueError(
f"Length of ascending ({len(ascending)}) != length of by ({len(by)})"
)
if len(by) > 1:
from pandas.core.sorting import lexsort_indexer
keys = [self._get_label_or_level_values(x, axis=axis) for x in by]
indexer = lexsort_indexer(keys, orders=ascending, na_position=na_position)
indexer = ensure_platform_int(indexer)
else:
from pandas.core.sorting import nargsort
by = by[0]
k = self._get_label_or_level_values(by, axis=axis)
if isinstance(ascending, (tuple, list)):
ascending = ascending[0]
indexer = nargsort(
k, kind=kind, ascending=ascending, na_position=na_position
)
new_data = self._data.take(
indexer, axis=self._get_block_manager_axis(axis), verify=False
)
if ignore_index:
new_data.axes[1] = ibase.default_index(len(indexer))
if inplace:
return self._update_inplace(new_data)
else:
return self._constructor(new_data).__finalize__(self)
def sort_index(
self,
axis=0,
level=None,
ascending: bool = True,
inplace: bool = False,
kind: str = "quicksort",
na_position: str = "last",
sort_remaining: bool = True,
ignore_index: bool = False,
):
"""
Sort object by labels (along an axis).
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis along which to sort. The value 0 identifies the rows,
and 1 identifies the columns.
level : int or level name or list of ints or list of level names
If not None, sort on values in specified index level(s).
ascending : bool, default True
Sort ascending vs. descending.
inplace : bool, default False
If True, perform operation in-place.
kind : {'quicksort', 'mergesort', 'heapsort'}, default 'quicksort'
Choice of sorting algorithm. See also ndarray.np.sort for more
information. `mergesort` is the only stable algorithm. For
DataFrames, this option is only applied when sorting on a single
column or label.
na_position : {'first', 'last'}, default 'last'
Puts NaNs at the beginning if `first`; `last` puts NaNs at the end.
Not implemented for MultiIndex.
sort_remaining : bool, default True
If True and sorting by level and index is multilevel, sort by other
levels too (in order) after sorting by specified level.
ignore_index : bool, default False
If True, the resulting axis will be labeled 0, 1, …, n - 1.
.. versionadded:: 1.0.0
Returns
-------
sorted_obj : DataFrame or None
DataFrame with sorted index if inplace=False, None otherwise.
"""
# TODO: this can be combined with Series.sort_index impl as
# almost identical
inplace = validate_bool_kwarg(inplace, "inplace")
axis = self._get_axis_number(axis)
labels = self._get_axis(axis)
# make sure that the axis is lexsorted to start
# if not we need to reconstruct to get the correct indexer
labels = labels._sort_levels_monotonic()
if level is not None:
new_axis, indexer = labels.sortlevel(
level, ascending=ascending, sort_remaining=sort_remaining
)
elif isinstance(labels, ABCMultiIndex):
from pandas.core.sorting import lexsort_indexer
indexer = lexsort_indexer(
labels._get_codes_for_sorting(),
orders=ascending,
na_position=na_position,
)
else:
from pandas.core.sorting import nargsort
# Check monotonic-ness before sort an index
# GH11080
if (ascending and labels.is_monotonic_increasing) or (
not ascending and labels.is_monotonic_decreasing
):
if inplace:
return
else:
return self.copy()
indexer = nargsort(
labels, kind=kind, ascending=ascending, na_position=na_position
)
baxis = self._get_block_manager_axis(axis)
new_data = self._data.take(indexer, axis=baxis, verify=False)
# reconstruct axis if needed
new_data.axes[baxis] = new_data.axes[baxis]._sort_levels_monotonic()
if ignore_index:
new_data.axes[1] = ibase.default_index(len(indexer))
if inplace:
return self._update_inplace(new_data)
else:
return self._constructor(new_data).__finalize__(self)
def nlargest(self, n, columns, keep="first") -> "DataFrame":
"""
Return the first `n` rows ordered by `columns` in descending order.
Return the first `n` rows with the largest values in `columns`, in
descending order. The columns that are not specified are returned as
well, but not used for ordering.
This method is equivalent to
``df.sort_values(columns, ascending=False).head(n)``, but more
performant.
Parameters
----------
n : int
Number of rows to return.
columns : label or list of labels
Column label(s) to order by.
keep : {'first', 'last', 'all'}, default 'first'
Where there are duplicate values:
- `first` : prioritize the first occurrence(s)
- `last` : prioritize the last occurrence(s)
- ``all`` : do not drop any duplicates, even it means
selecting more than `n` items.
.. versionadded:: 0.24.0
Returns
-------
DataFrame
The first `n` rows ordered by the given columns in descending
order.
See Also
--------
DataFrame.nsmallest : Return the first `n` rows ordered by `columns` in
ascending order.
DataFrame.sort_values : Sort DataFrame by the values.
DataFrame.head : Return the first `n` rows without re-ordering.
Notes
-----
This function cannot be used with all column types. For example, when
specifying columns with `object` or `category` dtypes, ``TypeError`` is
raised.
Examples
--------
>>> df = pd.DataFrame({'population': [59000000, 65000000, 434000,
... 434000, 434000, 337000, 11300,
... 11300, 11300],
... 'GDP': [1937894, 2583560 , 12011, 4520, 12128,
... 17036, 182, 38, 311],
... 'alpha-2': ["IT", "FR", "MT", "MV", "BN",
... "IS", "NR", "TV", "AI"]},
... index=["Italy", "France", "Malta",
... "Maldives", "Brunei", "Iceland",
... "Nauru", "Tuvalu", "Anguilla"])
>>> df
population GDP alpha-2
Italy 59000000 1937894 IT
France 65000000 2583560 FR
Malta 434000 12011 MT
Maldives 434000 4520 MV
Brunei 434000 12128 BN
Iceland 337000 17036 IS
Nauru 11300 182 NR
Tuvalu 11300 38 TV
Anguilla 11300 311 AI
In the following example, we will use ``nlargest`` to select the three
rows having the largest values in column "population".
>>> df.nlargest(3, 'population')
population GDP alpha-2
France 65000000 2583560 FR
Italy 59000000 1937894 IT
Malta 434000 12011 MT
When using ``keep='last'``, ties are resolved in reverse order:
>>> df.nlargest(3, 'population', keep='last')
population GDP alpha-2
France 65000000 2583560 FR
Italy 59000000 1937894 IT
Brunei 434000 12128 BN
When using ``keep='all'``, all duplicate items are maintained:
>>> df.nlargest(3, 'population', keep='all')
population GDP alpha-2
France 65000000 2583560 FR
Italy 59000000 1937894 IT
Malta 434000 12011 MT
Maldives 434000 4520 MV
Brunei 434000 12128 BN
To order by the largest values in column "population" and then "GDP",
we can specify multiple columns like in the next example.
>>> df.nlargest(3, ['population', 'GDP'])
population GDP alpha-2
France 65000000 2583560 FR
Italy 59000000 1937894 IT
Brunei 434000 12128 BN
"""
return algorithms.SelectNFrame(self, n=n, keep=keep, columns=columns).nlargest()
def nsmallest(self, n, columns, keep="first") -> "DataFrame":
"""
Return the first `n` rows ordered by `columns` in ascending order.
Return the first `n` rows with the smallest values in `columns`, in
ascending order. The columns that are not specified are returned as
well, but not used for ordering.
This method is equivalent to
``df.sort_values(columns, ascending=True).head(n)``, but more
performant.
Parameters
----------
n : int
Number of items to retrieve.
columns : list or str
Column name or names to order by.
keep : {'first', 'last', 'all'}, default 'first'
Where there are duplicate values:
- ``first`` : take the first occurrence.
- ``last`` : take the last occurrence.
- ``all`` : do not drop any duplicates, even it means
selecting more than `n` items.
.. versionadded:: 0.24.0
Returns
-------
DataFrame
See Also
--------
DataFrame.nlargest : Return the first `n` rows ordered by `columns` in
descending order.
DataFrame.sort_values : Sort DataFrame by the values.
DataFrame.head : Return the first `n` rows without re-ordering.
Examples
--------
>>> df = pd.DataFrame({'population': [59000000, 65000000, 434000,
... 434000, 434000, 337000, 11300,
... 11300, 11300],
... 'GDP': [1937894, 2583560 , 12011, 4520, 12128,
... 17036, 182, 38, 311],
... 'alpha-2': ["IT", "FR", "MT", "MV", "BN",
... "IS", "NR", "TV", "AI"]},
... index=["Italy", "France", "Malta",
... "Maldives", "Brunei", "Iceland",
... "Nauru", "Tuvalu", "Anguilla"])
>>> df
population GDP alpha-2
Italy 59000000 1937894 IT
France 65000000 2583560 FR
Malta 434000 12011 MT
Maldives 434000 4520 MV
Brunei 434000 12128 BN
Iceland 337000 17036 IS
Nauru 11300 182 NR
Tuvalu 11300 38 TV
Anguilla 11300 311 AI
In the following example, we will use ``nsmallest`` to select the
three rows having the smallest values in column "a".
>>> df.nsmallest(3, 'population')
population GDP alpha-2
Nauru 11300 182 NR
Tuvalu 11300 38 TV
Anguilla 11300 311 AI
When using ``keep='last'``, ties are resolved in reverse order:
>>> df.nsmallest(3, 'population', keep='last')
population GDP alpha-2
Anguilla 11300 311 AI
Tuvalu 11300 38 TV
Nauru 11300 182 NR
When using ``keep='all'``, all duplicate items are maintained:
>>> df.nsmallest(3, 'population', keep='all')
population GDP alpha-2
Nauru 11300 182 NR
Tuvalu 11300 38 TV
Anguilla 11300 311 AI
To order by the largest values in column "a" and then "c", we can
specify multiple columns like in the next example.
>>> df.nsmallest(3, ['population', 'GDP'])
population GDP alpha-2
Tuvalu 11300 38 TV
Nauru 11300 182 NR
Anguilla 11300 311 AI
"""
return algorithms.SelectNFrame(
self, n=n, keep=keep, columns=columns
).nsmallest()
def swaplevel(self, i=-2, j=-1, axis=0) -> "DataFrame":
"""
Swap levels i and j in a MultiIndex on a particular axis.
Parameters
----------
i, j : int or str
Levels of the indices to be swapped. Can pass level name as string.
Returns
-------
DataFrame
"""
result = self.copy()
axis = self._get_axis_number(axis)
if axis == 0:
result.index = result.index.swaplevel(i, j)
else:
result.columns = result.columns.swaplevel(i, j)
return result
def reorder_levels(self, order, axis=0) -> "DataFrame":
"""
Rearrange index levels using input order. May not drop or duplicate levels.
Parameters
----------
order : list of int or list of str
List representing new level order. Reference level by number
(position) or by key (label).
axis : int
Where to reorder levels.
Returns
-------
DataFrame
"""
axis = self._get_axis_number(axis)
if not isinstance(self._get_axis(axis), ABCMultiIndex): # pragma: no cover
raise TypeError("Can only reorder levels on a hierarchical axis.")
result = self.copy()
if axis == 0:
result.index = result.index.reorder_levels(order)
else:
result.columns = result.columns.reorder_levels(order)
return result
# ----------------------------------------------------------------------
# Arithmetic / combination related
def _combine_frame(self, other, func, fill_value=None, level=None):
# at this point we have `self._indexed_same(other)`
if fill_value is None:
# since _arith_op may be called in a loop, avoid function call
# overhead if possible by doing this check once
_arith_op = func
else:
def _arith_op(left, right):
# for the mixed_type case where we iterate over columns,
# _arith_op(left, right) is equivalent to
# left._binop(right, func, fill_value=fill_value)
left, right = ops.fill_binop(left, right, fill_value)
return func(left, right)
if ops.should_series_dispatch(self, other, func):
# iterate over columns
new_data = ops.dispatch_to_series(self, other, _arith_op)
else:
with np.errstate(all="ignore"):
res_values = _arith_op(self.values, other.values)
new_data = dispatch_fill_zeros(func, self.values, other.values, res_values)
return new_data
def _combine_match_index(self, other, func):
# at this point we have `self.index.equals(other.index)`
if ops.should_series_dispatch(self, other, func):
# operate column-wise; avoid costly object-casting in `.values`
new_data = ops.dispatch_to_series(self, other, func)
else:
# fastpath --> operate directly on values
with np.errstate(all="ignore"):
new_data = func(self.values.T, other.values).T
return new_data
def _construct_result(self, result) -> "DataFrame":
"""
Wrap the result of an arithmetic, comparison, or logical operation.
Parameters
----------
result : DataFrame
Returns
-------
DataFrame
"""
out = self._constructor(result, index=self.index, copy=False)
# Pin columns instead of passing to constructor for compat with
# non-unique columns case
out.columns = self.columns
return out
def combine(
self, other: "DataFrame", func, fill_value=None, overwrite=True
) -> "DataFrame":
"""
Perform column-wise combine with another DataFrame.
Combines a DataFrame with `other` DataFrame using `func`
to element-wise combine columns. The row and column indexes of the
resulting DataFrame will be the union of the two.
Parameters
----------
other : DataFrame
The DataFrame to merge column-wise.
func : function
Function that takes two series as inputs and return a Series or a
scalar. Used to merge the two dataframes column by columns.
fill_value : scalar value, default None
The value to fill NaNs with prior to passing any column to the
merge func.
overwrite : bool, default True
If True, columns in `self` that do not exist in `other` will be
overwritten with NaNs.
Returns
-------
DataFrame
Combination of the provided DataFrames.
See Also
--------
DataFrame.combine_first : Combine two DataFrame objects and default to
non-null values in frame calling the method.
Examples
--------
Combine using a simple function that chooses the smaller column.
>>> df1 = pd.DataFrame({'A': [0, 0], 'B': [4, 4]})
>>> df2 = pd.DataFrame({'A': [1, 1], 'B': [3, 3]})
>>> take_smaller = lambda s1, s2: s1 if s1.sum() < s2.sum() else s2
>>> df1.combine(df2, take_smaller)
A B
0 0 3
1 0 3
Example using a true element-wise combine function.
>>> df1 = pd.DataFrame({'A': [5, 0], 'B': [2, 4]})
>>> df2 = pd.DataFrame({'A': [1, 1], 'B': [3, 3]})
>>> df1.combine(df2, np.minimum)
A B
0 1 2
1 0 3
Using `fill_value` fills Nones prior to passing the column to the
merge function.
>>> df1 = pd.DataFrame({'A': [0, 0], 'B': [None, 4]})
>>> df2 = pd.DataFrame({'A': [1, 1], 'B': [3, 3]})
>>> df1.combine(df2, take_smaller, fill_value=-5)
A B
0 0 -5.0
1 0 4.0
However, if the same element in both dataframes is None, that None
is preserved
>>> df1 = pd.DataFrame({'A': [0, 0], 'B': [None, 4]})
>>> df2 = pd.DataFrame({'A': [1, 1], 'B': [None, 3]})
>>> df1.combine(df2, take_smaller, fill_value=-5)
A B
0 0 -5.0
1 0 3.0
Example that demonstrates the use of `overwrite` and behavior when
the axis differ between the dataframes.
>>> df1 = pd.DataFrame({'A': [0, 0], 'B': [4, 4]})
>>> df2 = pd.DataFrame({'B': [3, 3], 'C': [-10, 1], }, index=[1, 2])
>>> df1.combine(df2, take_smaller)
A B C
0 NaN NaN NaN
1 NaN 3.0 -10.0
2 NaN 3.0 1.0
>>> df1.combine(df2, take_smaller, overwrite=False)
A B C
0 0.0 NaN NaN
1 0.0 3.0 -10.0
2 NaN 3.0 1.0
Demonstrating the preference of the passed in dataframe.
>>> df2 = pd.DataFrame({'B': [3, 3], 'C': [1, 1], }, index=[1, 2])
>>> df2.combine(df1, take_smaller)
A B C
0 0.0 NaN NaN
1 0.0 3.0 NaN
2 NaN 3.0 NaN
>>> df2.combine(df1, take_smaller, overwrite=False)
A B C
0 0.0 NaN NaN
1 0.0 3.0 1.0
2 NaN 3.0 1.0
"""
other_idxlen = len(other.index) # save for compare
this, other = self.align(other, copy=False)
new_index = this.index
if other.empty and len(new_index) == len(self.index):
return self.copy()
if self.empty and len(other) == other_idxlen:
return other.copy()
# sorts if possible
new_columns = this.columns.union(other.columns)
do_fill = fill_value is not None
result = {}
for col in new_columns:
series = this[col]
otherSeries = other[col]
this_dtype = series.dtype
other_dtype = otherSeries.dtype
this_mask = isna(series)
other_mask = isna(otherSeries)
# don't overwrite columns unnecessarily
# DO propagate if this column is not in the intersection
if not overwrite and other_mask.all():
result[col] = this[col].copy()
continue
if do_fill:
series = series.copy()
otherSeries = otherSeries.copy()
series[this_mask] = fill_value
otherSeries[other_mask] = fill_value
if col not in self.columns:
# If self DataFrame does not have col in other DataFrame,
# try to promote series, which is all NaN, as other_dtype.
new_dtype = other_dtype
try:
series = series.astype(new_dtype, copy=False)
except ValueError:
# e.g. new_dtype is integer types
pass
else:
# if we have different dtypes, possibly promote
new_dtype = find_common_type([this_dtype, other_dtype])
if not is_dtype_equal(this_dtype, new_dtype):
series = series.astype(new_dtype)
if not is_dtype_equal(other_dtype, new_dtype):
otherSeries = otherSeries.astype(new_dtype)
arr = func(series, otherSeries)
arr = maybe_downcast_to_dtype(arr, this_dtype)
result[col] = arr
# convert_objects just in case
return self._constructor(result, index=new_index, columns=new_columns)
def combine_first(self, other: "DataFrame") -> "DataFrame":
"""
Update null elements with value in the same location in `other`.
Combine two DataFrame objects by filling null values in one DataFrame
with non-null values from other DataFrame. The row and column indexes
of the resulting DataFrame will be the union of the two.
Parameters
----------
other : DataFrame
Provided DataFrame to use to fill null values.
Returns
-------
DataFrame
See Also
--------
DataFrame.combine : Perform series-wise operation on two DataFrames
using a given function.
Examples
--------
>>> df1 = pd.DataFrame({'A': [None, 0], 'B': [None, 4]})
>>> df2 = pd.DataFrame({'A': [1, 1], 'B': [3, 3]})
>>> df1.combine_first(df2)
A B
0 1.0 3.0
1 0.0 4.0
Null values still persist if the location of that null value
does not exist in `other`
>>> df1 = pd.DataFrame({'A': [None, 0], 'B': [4, None]})
>>> df2 = pd.DataFrame({'B': [3, 3], 'C': [1, 1]}, index=[1, 2])
>>> df1.combine_first(df2)
A B C
0 NaN 4.0 NaN
1 0.0 3.0 1.0
2 NaN 3.0 1.0
"""
import pandas.core.computation.expressions as expressions
def extract_values(arr):
# Does two things:
# 1. maybe gets the values from the Series / Index
# 2. convert datelike to i8
if isinstance(arr, (ABCIndexClass, ABCSeries)):
arr = arr._values
if needs_i8_conversion(arr):
if is_extension_array_dtype(arr.dtype):
arr = arr.asi8
else:
arr = arr.view("i8")
return arr
def combiner(x, y):
mask = isna(x)
if isinstance(mask, (ABCIndexClass, ABCSeries)):
mask = mask._values
x_values = extract_values(x)
y_values = extract_values(y)
# If the column y in other DataFrame is not in first DataFrame,
# just return y_values.
if y.name not in self.columns:
return y_values
return expressions.where(mask, y_values, x_values)
return self.combine(other, combiner, overwrite=False)
def update(
self, other, join="left", overwrite=True, filter_func=None, errors="ignore"
) -> None:
"""
Modify in place using non-NA values from another DataFrame.
Aligns on indices. There is no return value.
Parameters
----------
other : DataFrame, or object coercible into a DataFrame
Should have at least one matching index/column label
with the original DataFrame. If a Series is passed,
its name attribute must be set, and that will be
used as the column name to align with the original DataFrame.
join : {'left'}, default 'left'
Only left join is implemented, keeping the index and columns of the
original object.
overwrite : bool, default True
How to handle non-NA values for overlapping keys:
* True: overwrite original DataFrame's values
with values from `other`.
* False: only update values that are NA in
the original DataFrame.
filter_func : callable(1d-array) -> bool 1d-array, optional
Can choose to replace values other than NA. Return True for values
that should be updated.
errors : {'raise', 'ignore'}, default 'ignore'
If 'raise', will raise a ValueError if the DataFrame and `other`
both contain non-NA data in the same place.
.. versionchanged:: 0.24.0
Changed from `raise_conflict=False|True`
to `errors='ignore'|'raise'`.
Returns
-------
None : method directly changes calling object
Raises
------
ValueError
* When `errors='raise'` and there's overlapping non-NA data.
* When `errors` is not either `'ignore'` or `'raise'`
NotImplementedError
* If `join != 'left'`
See Also
--------
dict.update : Similar method for dictionaries.
DataFrame.merge : For column(s)-on-columns(s) operations.
Examples
--------
>>> df = pd.DataFrame({'A': [1, 2, 3],
... 'B': [400, 500, 600]})
>>> new_df = pd.DataFrame({'B': [4, 5, 6],
... 'C': [7, 8, 9]})
>>> df.update(new_df)
>>> df
A B
0 1 4
1 2 5
2 3 6
The DataFrame's length does not increase as a result of the update,
only values at matching index/column labels are updated.
>>> df = pd.DataFrame({'A': ['a', 'b', 'c'],
... 'B': ['x', 'y', 'z']})
>>> new_df = pd.DataFrame({'B': ['d', 'e', 'f', 'g', 'h', 'i']})
>>> df.update(new_df)
>>> df
A B
0 a d
1 b e
2 c f
For Series, it's name attribute must be set.
>>> df = pd.DataFrame({'A': ['a', 'b', 'c'],
... 'B': ['x', 'y', 'z']})
>>> new_column = pd.Series(['d', 'e'], name='B', index=[0, 2])
>>> df.update(new_column)
>>> df
A B
0 a d
1 b y
2 c e
>>> df = pd.DataFrame({'A': ['a', 'b', 'c'],
... 'B': ['x', 'y', 'z']})
>>> new_df = pd.DataFrame({'B': ['d', 'e']}, index=[1, 2])
>>> df.update(new_df)
>>> df
A B
0 a x
1 b d
2 c e
If `other` contains NaNs the corresponding values are not updated
in the original dataframe.
>>> df = pd.DataFrame({'A': [1, 2, 3],
... 'B': [400, 500, 600]})
>>> new_df = pd.DataFrame({'B': [4, np.nan, 6]})
>>> df.update(new_df)
>>> df
A B
0 1 4.0
1 2 500.0
2 3 6.0
"""
import pandas.core.computation.expressions as expressions
# TODO: Support other joins
if join != "left": # pragma: no cover
raise NotImplementedError("Only left join is supported")
if errors not in ["ignore", "raise"]:
raise ValueError("The parameter errors must be either 'ignore' or 'raise'")
if not isinstance(other, DataFrame):
other = DataFrame(other)
other = other.reindex_like(self)
for col in self.columns:
this = self[col]._values
that = other[col]._values
if filter_func is not None:
with np.errstate(all="ignore"):
mask = ~filter_func(this) | isna(that)
else:
if errors == "raise":
mask_this = notna(that)
mask_that = notna(this)
if any(mask_this & mask_that):
raise ValueError("Data overlaps.")
if overwrite:
mask = isna(that)
else:
mask = notna(this)
# don't overwrite columns unnecessarily
if mask.all():
continue
self[col] = expressions.where(mask, this, that)
# ----------------------------------------------------------------------
# Data reshaping
@Appender(
"""
Examples
--------
>>> df = pd.DataFrame({'Animal': ['Falcon', 'Falcon',
... 'Parrot', 'Parrot'],
... 'Max Speed': [380., 370., 24., 26.]})
>>> df
Animal Max Speed
0 Falcon 380.0
1 Falcon 370.0
2 Parrot 24.0
3 Parrot 26.0
>>> df.groupby(['Animal']).mean()
Max Speed
Animal
Falcon 375.0
Parrot 25.0
**Hierarchical Indexes**
We can groupby different levels of a hierarchical index
using the `level` parameter:
>>> arrays = [['Falcon', 'Falcon', 'Parrot', 'Parrot'],
... ['Captive', 'Wild', 'Captive', 'Wild']]
>>> index = pd.MultiIndex.from_arrays(arrays, names=('Animal', 'Type'))
>>> df = pd.DataFrame({'Max Speed': [390., 350., 30., 20.]},
... index=index)
>>> df
Max Speed
Animal Type
Falcon Captive 390.0
Wild 350.0
Parrot Captive 30.0
Wild 20.0
>>> df.groupby(level=0).mean()
Max Speed
Animal
Falcon 370.0
Parrot 25.0
>>> df.groupby(level="Type").mean()
Max Speed
Type
Captive 210.0
Wild 185.0
"""
)
@Appender(_shared_docs["groupby"] % _shared_doc_kwargs)
def groupby(
self,
by=None,
axis=0,
level=None,
as_index: bool = True,
sort: bool = True,
group_keys: bool = True,
squeeze: bool = False,
observed: bool = False,
) -> "DataFrameGroupBy":
from pandas.core.groupby.generic import DataFrameGroupBy
if level is None and by is None:
raise TypeError("You have to supply one of 'by' and 'level'")
axis = self._get_axis_number(axis)
return DataFrameGroupBy(
obj=self,
keys=by,
axis=axis,
level=level,
as_index=as_index,
sort=sort,
group_keys=group_keys,
squeeze=squeeze,
observed=observed,
)
_shared_docs[
"pivot"
] = """
Return reshaped DataFrame organized by given index / column values.
Reshape data (produce a "pivot" table) based on column values. Uses
unique values from specified `index` / `columns` to form axes of the
resulting DataFrame. This function does not support data
aggregation, multiple values will result in a MultiIndex in the
columns. See the :ref:`User Guide <reshaping>` for more on reshaping.
Parameters
----------%s
index : str or object, optional
Column to use to make new frame's index. If None, uses
existing index.
columns : str or object
Column to use to make new frame's columns.
values : str, object or a list of the previous, optional
Column(s) to use for populating new frame's values. If not
specified, all remaining columns will be used and the result will
have hierarchically indexed columns.
.. versionchanged:: 0.23.0
Also accept list of column names.
Returns
-------
DataFrame
Returns reshaped DataFrame.
Raises
------
ValueError:
When there are any `index`, `columns` combinations with multiple
values. `DataFrame.pivot_table` when you need to aggregate.
See Also
--------
DataFrame.pivot_table : Generalization of pivot that can handle
duplicate values for one index/column pair.
DataFrame.unstack : Pivot based on the index values instead of a
column.
Notes
-----
For finer-tuned control, see hierarchical indexing documentation along
with the related stack/unstack methods.
Examples
--------
>>> df = pd.DataFrame({'foo': ['one', 'one', 'one', 'two', 'two',
... 'two'],
... 'bar': ['A', 'B', 'C', 'A', 'B', 'C'],
... 'baz': [1, 2, 3, 4, 5, 6],
... 'zoo': ['x', 'y', 'z', 'q', 'w', 't']})
>>> df
foo bar baz zoo
0 one A 1 x
1 one B 2 y
2 one C 3 z
3 two A 4 q
4 two B 5 w
5 two C 6 t
>>> df.pivot(index='foo', columns='bar', values='baz')
bar A B C
foo
one 1 2 3
two 4 5 6
>>> df.pivot(index='foo', columns='bar')['baz']
bar A B C
foo
one 1 2 3
two 4 5 6
>>> df.pivot(index='foo', columns='bar', values=['baz', 'zoo'])
baz zoo
bar A B C A B C
foo
one 1 2 3 x y z
two 4 5 6 q w t
A ValueError is raised if there are any duplicates.
>>> df = pd.DataFrame({"foo": ['one', 'one', 'two', 'two'],
... "bar": ['A', 'A', 'B', 'C'],
... "baz": [1, 2, 3, 4]})
>>> df
foo bar baz
0 one A 1
1 one A 2
2 two B 3
3 two C 4
Notice that the first two rows are the same for our `index`
and `columns` arguments.
>>> df.pivot(index='foo', columns='bar', values='baz')
Traceback (most recent call last):
...
ValueError: Index contains duplicate entries, cannot reshape
"""
@Substitution("")
@Appender(_shared_docs["pivot"])
def pivot(self, index=None, columns=None, values=None) -> "DataFrame":
from pandas.core.reshape.pivot import pivot
return pivot(self, index=index, columns=columns, values=values)
_shared_docs[
"pivot_table"
] = """
Create a spreadsheet-style pivot table as a DataFrame.
The levels in the pivot table will be stored in MultiIndex objects
(hierarchical indexes) on the index and columns of the result DataFrame.
Parameters
----------%s
values : column to aggregate, optional
index : column, Grouper, array, or list of the previous
If an array is passed, it must be the same length as the data. The
list can contain any of the other types (except list).
Keys to group by on the pivot table index. If an array is passed,
it is being used as the same manner as column values.
columns : column, Grouper, array, or list of the previous
If an array is passed, it must be the same length as the data. The
list can contain any of the other types (except list).
Keys to group by on the pivot table column. If an array is passed,
it is being used as the same manner as column values.
aggfunc : function, list of functions, dict, default numpy.mean
If list of functions passed, the resulting pivot table will have
hierarchical columns whose top level are the function names
(inferred from the function objects themselves)
If dict is passed, the key is column to aggregate and value
is function or list of functions.
fill_value : scalar, default None
Value to replace missing values with.
margins : bool, default False
Add all row / columns (e.g. for subtotal / grand totals).
dropna : bool, default True
Do not include columns whose entries are all NaN.
margins_name : str, default 'All'
Name of the row / column that will contain the totals
when margins is True.
observed : bool, default False
This only applies if any of the groupers are Categoricals.
If True: only show observed values for categorical groupers.
If False: show all values for categorical groupers.
.. versionchanged:: 0.25.0
Returns
-------
DataFrame
An Excel style pivot table.
See Also
--------
DataFrame.pivot : Pivot without aggregation that can handle
non-numeric data.
Examples
--------
>>> df = pd.DataFrame({"A": ["foo", "foo", "foo", "foo", "foo",
... "bar", "bar", "bar", "bar"],
... "B": ["one", "one", "one", "two", "two",
... "one", "one", "two", "two"],
... "C": ["small", "large", "large", "small",
... "small", "large", "small", "small",
... "large"],
... "D": [1, 2, 2, 3, 3, 4, 5, 6, 7],
... "E": [2, 4, 5, 5, 6, 6, 8, 9, 9]})
>>> df
A B C D E
0 foo one small 1 2
1 foo one large 2 4
2 foo one large 2 5
3 foo two small 3 5
4 foo two small 3 6
5 bar one large 4 6
6 bar one small 5 8
7 bar two small 6 9
8 bar two large 7 9
This first example aggregates values by taking the sum.
>>> table = pd.pivot_table(df, values='D', index=['A', 'B'],
... columns=['C'], aggfunc=np.sum)
>>> table
C large small
A B
bar one 4.0 5.0
two 7.0 6.0
foo one 4.0 1.0
two NaN 6.0
We can also fill missing values using the `fill_value` parameter.
>>> table = pd.pivot_table(df, values='D', index=['A', 'B'],
... columns=['C'], aggfunc=np.sum, fill_value=0)
>>> table
C large small
A B
bar one 4 5
two 7 6
foo one 4 1
two 0 6
The next example aggregates by taking the mean across multiple columns.
>>> table = pd.pivot_table(df, values=['D', 'E'], index=['A', 'C'],
... aggfunc={'D': np.mean,
... 'E': np.mean})
>>> table
D E
A C
bar large 5.500000 7.500000
small 5.500000 8.500000
foo large 2.000000 4.500000
small 2.333333 4.333333
We can also calculate multiple types of aggregations for any given
value column.
>>> table = pd.pivot_table(df, values=['D', 'E'], index=['A', 'C'],
... aggfunc={'D': np.mean,
... 'E': [min, max, np.mean]})
>>> table
D E
mean max mean min
A C
bar large 5.500000 9.0 7.500000 6.0
small 5.500000 9.0 8.500000 8.0
foo large 2.000000 5.0 4.500000 4.0
small 2.333333 6.0 4.333333 2.0
"""
@Substitution("")
@Appender(_shared_docs["pivot_table"])
def pivot_table(
self,
values=None,
index=None,
columns=None,
aggfunc="mean",
fill_value=None,
margins=False,
dropna=True,
margins_name="All",
observed=False,
) -> "DataFrame":
from pandas.core.reshape.pivot import pivot_table
return pivot_table(
self,
values=values,
index=index,
columns=columns,
aggfunc=aggfunc,
fill_value=fill_value,
margins=margins,
dropna=dropna,
margins_name=margins_name,
observed=observed,
)
def stack(self, level=-1, dropna=True):
"""
Stack the prescribed level(s) from columns to index.
Return a reshaped DataFrame or Series having a multi-level
index with one or more new inner-most levels compared to the current
DataFrame. The new inner-most levels are created by pivoting the
columns of the current dataframe:
- if the columns have a single level, the output is a Series;
- if the columns have multiple levels, the new index
level(s) is (are) taken from the prescribed level(s) and
the output is a DataFrame.
The new index levels are sorted.
Parameters
----------
level : int, str, list, default -1
Level(s) to stack from the column axis onto the index
axis, defined as one index or label, or a list of indices
or labels.
dropna : bool, default True
Whether to drop rows in the resulting Frame/Series with
missing values. Stacking a column level onto the index
axis can create combinations of index and column values
that are missing from the original dataframe. See Examples
section.
Returns
-------
DataFrame or Series
Stacked dataframe or series.
See Also
--------
DataFrame.unstack : Unstack prescribed level(s) from index axis
onto column axis.
DataFrame.pivot : Reshape dataframe from long format to wide
format.
DataFrame.pivot_table : Create a spreadsheet-style pivot table
as a DataFrame.
Notes
-----
The function is named by analogy with a collection of books
being reorganized from being side by side on a horizontal
position (the columns of the dataframe) to being stacked
vertically on top of each other (in the index of the
dataframe).
Examples
--------
**Single level columns**
>>> df_single_level_cols = pd.DataFrame([[0, 1], [2, 3]],
... index=['cat', 'dog'],
... columns=['weight', 'height'])
Stacking a dataframe with a single level column axis returns a Series:
>>> df_single_level_cols
weight height
cat 0 1
dog 2 3
>>> df_single_level_cols.stack()
cat weight 0
height 1
dog weight 2
height 3
dtype: int64
**Multi level columns: simple case**
>>> multicol1 = pd.MultiIndex.from_tuples([('weight', 'kg'),
... ('weight', 'pounds')])
>>> df_multi_level_cols1 = pd.DataFrame([[1, 2], [2, 4]],
... index=['cat', 'dog'],
... columns=multicol1)
Stacking a dataframe with a multi-level column axis:
>>> df_multi_level_cols1
weight
kg pounds
cat 1 2
dog 2 4
>>> df_multi_level_cols1.stack()
weight
cat kg 1
pounds 2
dog kg 2
pounds 4
**Missing values**
>>> multicol2 = pd.MultiIndex.from_tuples([('weight', 'kg'),
... ('height', 'm')])
>>> df_multi_level_cols2 = pd.DataFrame([[1.0, 2.0], [3.0, 4.0]],
... index=['cat', 'dog'],
... columns=multicol2)
It is common to have missing values when stacking a dataframe
with multi-level columns, as the stacked dataframe typically
has more values than the original dataframe. Missing values
are filled with NaNs:
>>> df_multi_level_cols2
weight height
kg m
cat 1.0 2.0
dog 3.0 4.0
>>> df_multi_level_cols2.stack()
height weight
cat kg NaN 1.0
m 2.0 NaN
dog kg NaN 3.0
m 4.0 NaN
**Prescribing the level(s) to be stacked**
The first parameter controls which level or levels are stacked:
>>> df_multi_level_cols2.stack(0)
kg m
cat height NaN 2.0
weight 1.0 NaN
dog height NaN 4.0
weight 3.0 NaN
>>> df_multi_level_cols2.stack([0, 1])
cat height m 2.0
weight kg 1.0
dog height m 4.0
weight kg 3.0
dtype: float64
**Dropping missing values**
>>> df_multi_level_cols3 = pd.DataFrame([[None, 1.0], [2.0, 3.0]],
... index=['cat', 'dog'],
... columns=multicol2)
Note that rows where all values are missing are dropped by
default but this behaviour can be controlled via the dropna
keyword parameter:
>>> df_multi_level_cols3
weight height
kg m
cat NaN 1.0
dog 2.0 3.0
>>> df_multi_level_cols3.stack(dropna=False)
height weight
cat kg NaN NaN
m 1.0 NaN
dog kg NaN 2.0
m 3.0 NaN
>>> df_multi_level_cols3.stack(dropna=True)
height weight
cat m 1.0 NaN
dog kg NaN 2.0
m 3.0 NaN
"""
from pandas.core.reshape.reshape import stack, stack_multiple
if isinstance(level, (tuple, list)):
return stack_multiple(self, level, dropna=dropna)
else:
return stack(self, level, dropna=dropna)
def explode(self, column: Union[str, Tuple]) -> "DataFrame":
"""
Transform each element of a list-like to a row, replicating index values.
.. versionadded:: 0.25.0
Parameters
----------
column : str or tuple
Column to explode.
Returns
-------
DataFrame
Exploded lists to rows of the subset columns;
index will be duplicated for these rows.
Raises
------
ValueError :
if columns of the frame are not unique.
See Also
--------
DataFrame.unstack : Pivot a level of the (necessarily hierarchical)
index labels.
DataFrame.melt : Unpivot a DataFrame from wide format to long format.
Series.explode : Explode a DataFrame from list-like columns to long format.
Notes
-----
This routine will explode list-likes including lists, tuples,
Series, and np.ndarray. The result dtype of the subset rows will
be object. Scalars will be returned unchanged. Empty list-likes will
result in a np.nan for that row.
Examples
--------
>>> df = pd.DataFrame({'A': [[1, 2, 3], 'foo', [], [3, 4]], 'B': 1})
>>> df
A B
0 [1, 2, 3] 1
1 foo 1
2 [] 1
3 [3, 4] 1
>>> df.explode('A')
A B
0 1 1
0 2 1
0 3 1
1 foo 1
2 NaN 1
3 3 1
3 4 1
"""
if not (is_scalar(column) or isinstance(column, tuple)):
raise ValueError("column must be a scalar")
if not self.columns.is_unique:
raise ValueError("columns must be unique")
df = self.reset_index(drop=True)
# TODO: use overload to refine return type of reset_index
assert df is not None # needed for mypy
result = df[column].explode()
result = df.drop([column], axis=1).join(result)
result.index = self.index.take(result.index)
result = result.reindex(columns=self.columns, copy=False)
return result
def unstack(self, level=-1, fill_value=None):
"""
Pivot a level of the (necessarily hierarchical) index labels.
Returns a DataFrame having a new level of column labels whose inner-most level
consists of the pivoted index labels.
If the index is not a MultiIndex, the output will be a Series
(the analogue of stack when the columns are not a MultiIndex).
The level involved will automatically get sorted.
Parameters
----------
level : int, str, or list of these, default -1 (last level)
Level(s) of index to unstack, can pass level name.
fill_value : int, str or dict
Replace NaN with this value if the unstack produces missing values.
Returns
-------
Series or DataFrame
See Also
--------
DataFrame.pivot : Pivot a table based on column values.
DataFrame.stack : Pivot a level of the column labels (inverse operation
from `unstack`).
Examples
--------
>>> index = pd.MultiIndex.from_tuples([('one', 'a'), ('one', 'b'),
... ('two', 'a'), ('two', 'b')])
>>> s = pd.Series(np.arange(1.0, 5.0), index=index)
>>> s
one a 1.0
b 2.0
two a 3.0
b 4.0
dtype: float64
>>> s.unstack(level=-1)
a b
one 1.0 2.0
two 3.0 4.0
>>> s.unstack(level=0)
one two
a 1.0 3.0
b 2.0 4.0
>>> df = s.unstack(level=0)
>>> df.unstack()
one a 1.0
b 2.0
two a 3.0
b 4.0
dtype: float64
"""
from pandas.core.reshape.reshape import unstack
return unstack(self, level, fill_value)
_shared_docs[
"melt"
] = """
Unpivot a DataFrame from wide to long format, optionally leaving identifiers set.
This function is useful to massage a DataFrame into a format where one
or more columns are identifier variables (`id_vars`), while all other
columns, considered measured variables (`value_vars`), are "unpivoted" to
the row axis, leaving just two non-identifier columns, 'variable' and
'value'.
%(versionadded)s
Parameters
----------
id_vars : tuple, list, or ndarray, optional
Column(s) to use as identifier variables.
value_vars : tuple, list, or ndarray, optional
Column(s) to unpivot. If not specified, uses all columns that
are not set as `id_vars`.
var_name : scalar
Name to use for the 'variable' column. If None it uses
``frame.columns.name`` or 'variable'.
value_name : scalar, default 'value'
Name to use for the 'value' column.
col_level : int or str, optional
If columns are a MultiIndex then use this level to melt.
Returns
-------
DataFrame
Unpivoted DataFrame.
See Also
--------
%(other)s
pivot_table
DataFrame.pivot
Series.explode
Examples
--------
>>> df = pd.DataFrame({'A': {0: 'a', 1: 'b', 2: 'c'},
... 'B': {0: 1, 1: 3, 2: 5},
... 'C': {0: 2, 1: 4, 2: 6}})
>>> df
A B C
0 a 1 2
1 b 3 4
2 c 5 6
>>> %(caller)sid_vars=['A'], value_vars=['B'])
A variable value
0 a B 1
1 b B 3
2 c B 5
>>> %(caller)sid_vars=['A'], value_vars=['B', 'C'])
A variable value
0 a B 1
1 b B 3
2 c B 5
3 a C 2
4 b C 4
5 c C 6
The names of 'variable' and 'value' columns can be customized:
>>> %(caller)sid_vars=['A'], value_vars=['B'],
... var_name='myVarname', value_name='myValname')
A myVarname myValname
0 a B 1
1 b B 3
2 c B 5
If you have multi-index columns:
>>> df.columns = [list('ABC'), list('DEF')]
>>> df
A B C
D E F
0 a 1 2
1 b 3 4
2 c 5 6
>>> %(caller)scol_level=0, id_vars=['A'], value_vars=['B'])
A variable value
0 a B 1
1 b B 3
2 c B 5
>>> %(caller)sid_vars=[('A', 'D')], value_vars=[('B', 'E')])
(A, D) variable_0 variable_1 value
0 a B E 1
1 b B E 3
2 c B E 5
"""
@Appender(
_shared_docs["melt"]
% dict(
caller="df.melt(", versionadded=".. versionadded:: 0.20.0\n", other="melt"
)
)
def melt(
self,
id_vars=None,
value_vars=None,
var_name=None,
value_name="value",
col_level=None,
) -> "DataFrame":
from pandas.core.reshape.melt import melt
return melt(
self,
id_vars=id_vars,
value_vars=value_vars,
var_name=var_name,
value_name=value_name,
col_level=col_level,
)
# ----------------------------------------------------------------------
# Time series-related
def diff(self, periods=1, axis=0) -> "DataFrame":
"""
First discrete difference of element.
Calculates the difference of a DataFrame element compared with another
element in the DataFrame (default is the element in the same column
of the previous row).
Parameters
----------
periods : int, default 1
Periods to shift for calculating difference, accepts negative
values.
axis : {0 or 'index', 1 or 'columns'}, default 0
Take difference over rows (0) or columns (1).
Returns
-------
DataFrame
See Also
--------
Series.diff: First discrete difference for a Series.
DataFrame.pct_change: Percent change over given number of periods.
DataFrame.shift: Shift index by desired number of periods with an
optional time freq.
Notes
-----
For boolean dtypes, this uses :meth:`operator.xor` rather than
:meth:`operator.sub`.
Examples
--------
Difference with previous row
>>> df = pd.DataFrame({'a': [1, 2, 3, 4, 5, 6],
... 'b': [1, 1, 2, 3, 5, 8],
... 'c': [1, 4, 9, 16, 25, 36]})
>>> df
a b c
0 1 1 1
1 2 1 4
2 3 2 9
3 4 3 16
4 5 5 25
5 6 8 36
>>> df.diff()
a b c
0 NaN NaN NaN
1 1.0 0.0 3.0
2 1.0 1.0 5.0
3 1.0 1.0 7.0
4 1.0 2.0 9.0
5 1.0 3.0 11.0
Difference with previous column
>>> df.diff(axis=1)
a b c
0 NaN 0.0 0.0
1 NaN -1.0 3.0
2 NaN -1.0 7.0
3 NaN -1.0 13.0
4 NaN 0.0 20.0
5 NaN 2.0 28.0
Difference with 3rd previous row
>>> df.diff(periods=3)
a b c
0 NaN NaN NaN
1 NaN NaN NaN
2 NaN NaN NaN
3 3.0 2.0 15.0
4 3.0 4.0 21.0
5 3.0 6.0 27.0
Difference with following row
>>> df.diff(periods=-1)
a b c
0 -1.0 0.0 -3.0
1 -1.0 -1.0 -5.0
2 -1.0 -1.0 -7.0
3 -1.0 -2.0 -9.0
4 -1.0 -3.0 -11.0
5 NaN NaN NaN
"""
bm_axis = self._get_block_manager_axis(axis)
new_data = self._data.diff(n=periods, axis=bm_axis)
return self._constructor(new_data)
# ----------------------------------------------------------------------
# Function application
def _gotitem(
self,
key: Union[str, List[str]],
ndim: int,
subset: Optional[Union[Series, ABCDataFrame]] = None,
) -> Union[Series, ABCDataFrame]:
"""
Sub-classes to define. Return a sliced object.
Parameters
----------
key : string / list of selections
ndim : 1,2
requested ndim of result
subset : object, default None
subset to act on
"""
if subset is None:
subset = self
elif subset.ndim == 1: # is Series
return subset
# TODO: _shallow_copy(subset)?
return subset[key]
_agg_summary_and_see_also_doc = dedent(
"""
The aggregation operations are always performed over an axis, either the
index (default) or the column axis. This behavior is different from
`numpy` aggregation functions (`mean`, `median`, `prod`, `sum`, `std`,
`var`), where the default is to compute the aggregation of the flattened
array, e.g., ``numpy.mean(arr_2d)`` as opposed to
``numpy.mean(arr_2d, axis=0)``.
`agg` is an alias for `aggregate`. Use the alias.
See Also
--------
DataFrame.apply : Perform any type of operations.
DataFrame.transform : Perform transformation type operations.
core.groupby.GroupBy : Perform operations over groups.
core.resample.Resampler : Perform operations over resampled bins.
core.window.Rolling : Perform operations over rolling window.
core.window.Expanding : Perform operations over expanding window.
core.window.EWM : Perform operation over exponential weighted
window.
"""
)
_agg_examples_doc = dedent(
"""
Examples
--------
>>> df = pd.DataFrame([[1, 2, 3],
... [4, 5, 6],
... [7, 8, 9],
... [np.nan, np.nan, np.nan]],
... columns=['A', 'B', 'C'])
Aggregate these functions over the rows.
>>> df.agg(['sum', 'min'])
A B C
sum 12.0 15.0 18.0
min 1.0 2.0 3.0
Different aggregations per column.
>>> df.agg({'A' : ['sum', 'min'], 'B' : ['min', 'max']})
A B
max NaN 8.0
min 1.0 2.0
sum 12.0 NaN
Aggregate over the columns.
>>> df.agg("mean", axis="columns")
0 2.0
1 5.0
2 8.0
3 NaN
dtype: float64
"""
)
@Substitution(
see_also=_agg_summary_and_see_also_doc,
examples=_agg_examples_doc,
versionadded="\n.. versionadded:: 0.20.0\n",
**_shared_doc_kwargs,
)
@Appender(_shared_docs["aggregate"])
def aggregate(self, func, axis=0, *args, **kwargs):
axis = self._get_axis_number(axis)
result = None
try:
result, how = self._aggregate(func, axis=axis, *args, **kwargs)
except TypeError:
pass
if result is None:
return self.apply(func, axis=axis, args=args, **kwargs)
return result
def _aggregate(self, arg, axis=0, *args, **kwargs):
if axis == 1:
# NDFrame.aggregate returns a tuple, and we need to transpose
# only result
result, how = self.T._aggregate(arg, *args, **kwargs)
result = result.T if result is not None else result
return result, how
return super()._aggregate(arg, *args, **kwargs)
agg = aggregate
@Appender(_shared_docs["transform"] % _shared_doc_kwargs)
def transform(self, func, axis=0, *args, **kwargs) -> "DataFrame":
axis = self._get_axis_number(axis)
if axis == 1:
return self.T.transform(func, *args, **kwargs).T
return super().transform(func, *args, **kwargs)
def apply(self, func, axis=0, raw=False, result_type=None, args=(), **kwds):
"""
Apply a function along an axis of the DataFrame.
Objects passed to the function are Series objects whose index is
either the DataFrame's index (``axis=0``) or the DataFrame's columns
(``axis=1``). By default (``result_type=None``), the final return type
is inferred from the return type of the applied function. Otherwise,
it depends on the `result_type` argument.
Parameters
----------
func : function
Function to apply to each column or row.
axis : {0 or 'index', 1 or 'columns'}, default 0
Axis along which the function is applied:
* 0 or 'index': apply function to each column.
* 1 or 'columns': apply function to each row.
raw : bool, default False
Determines if row or column is passed as a Series or ndarray object:
* ``False`` : passes each row or column as a Series to the
function.
* ``True`` : the passed function will receive ndarray objects
instead.
If you are just applying a NumPy reduction function this will
achieve much better performance.
result_type : {'expand', 'reduce', 'broadcast', None}, default None
These only act when ``axis=1`` (columns):
* 'expand' : list-like results will be turned into columns.
* 'reduce' : returns a Series if possible rather than expanding
list-like results. This is the opposite of 'expand'.
* 'broadcast' : results will be broadcast to the original shape
of the DataFrame, the original index and columns will be
retained.
The default behaviour (None) depends on the return value of the
applied function: list-like results will be returned as a Series
of those. However if the apply function returns a Series these
are expanded to columns.
.. versionadded:: 0.23.0
args : tuple
Positional arguments to pass to `func` in addition to the
array/series.
**kwds
Additional keyword arguments to pass as keywords arguments to
`func`.
Returns
-------
Series or DataFrame
Result of applying ``func`` along the given axis of the
DataFrame.
See Also
--------
DataFrame.applymap: For elementwise operations.
DataFrame.aggregate: Only perform aggregating type operations.
DataFrame.transform: Only perform transforming type operations.
Examples
--------
>>> df = pd.DataFrame([[4, 9]] * 3, columns=['A', 'B'])
>>> df
A B
0 4 9
1 4 9
2 4 9
Using a numpy universal function (in this case the same as
``np.sqrt(df)``):
>>> df.apply(np.sqrt)
A B
0 2.0 3.0
1 2.0 3.0
2 2.0 3.0
Using a reducing function on either axis
>>> df.apply(np.sum, axis=0)
A 12
B 27
dtype: int64
>>> df.apply(np.sum, axis=1)
0 13
1 13
2 13
dtype: int64
Returning a list-like will result in a Series
>>> df.apply(lambda x: [1, 2], axis=1)
0 [1, 2]
1 [1, 2]
2 [1, 2]
dtype: object
Passing result_type='expand' will expand list-like results
to columns of a Dataframe
>>> df.apply(lambda x: [1, 2], axis=1, result_type='expand')
0 1
0 1 2
1 1 2
2 1 2
Returning a Series inside the function is similar to passing
``result_type='expand'``. The resulting column names
will be the Series index.
>>> df.apply(lambda x: pd.Series([1, 2], index=['foo', 'bar']), axis=1)
foo bar
0 1 2
1 1 2
2 1 2
Passing ``result_type='broadcast'`` will ensure the same shape
result, whether list-like or scalar is returned by the function,
and broadcast it along the axis. The resulting column names will
be the originals.
>>> df.apply(lambda x: [1, 2], axis=1, result_type='broadcast')
A B
0 1 2
1 1 2
2 1 2
"""
from pandas.core.apply import frame_apply
op = frame_apply(
self,
func=func,
axis=axis,
raw=raw,
result_type=result_type,
args=args,
kwds=kwds,
)
return op.get_result()
def applymap(self, func) -> "DataFrame":
"""
Apply a function to a Dataframe elementwise.
This method applies a function that accepts and returns a scalar
to every element of a DataFrame.
Parameters
----------
func : callable
Python function, returns a single value from a single value.
Returns
-------
DataFrame
Transformed DataFrame.
See Also
--------
DataFrame.apply : Apply a function along input axis of DataFrame.
Notes
-----
In the current implementation applymap calls `func` twice on the
first column/row to decide whether it can take a fast or slow
code path. This can lead to unexpected behavior if `func` has
side-effects, as they will take effect twice for the first
column/row.
Examples
--------
>>> df = pd.DataFrame([[1, 2.12], [3.356, 4.567]])
>>> df
0 1
0 1.000 2.120
1 3.356 4.567
>>> df.applymap(lambda x: len(str(x)))
0 1
0 3 4
1 5 5
Note that a vectorized version of `func` often exists, which will
be much faster. You could square each number elementwise.
>>> df.applymap(lambda x: x**2)
0 1
0 1.000000 4.494400
1 11.262736 20.857489
But it's better to avoid applymap in that case.
>>> df ** 2
0 1
0 1.000000 4.494400
1 11.262736 20.857489
"""
# if we have a dtype == 'M8[ns]', provide boxed values
def infer(x):
if x.empty:
return lib.map_infer(x, func)
return lib.map_infer(x.astype(object).values, func)
return self.apply(infer)
# ----------------------------------------------------------------------
# Merging / joining methods
def append(
self, other, ignore_index=False, verify_integrity=False, sort=False
) -> "DataFrame":
"""
Append rows of `other` to the end of caller, returning a new object.
Columns in `other` that are not in the caller are added as new columns.
Parameters
----------
other : DataFrame or Series/dict-like object, or list of these
The data to append.
ignore_index : bool, default False
If True, do not use the index labels.
verify_integrity : bool, default False
If True, raise ValueError on creating index with duplicates.
sort : bool, default False
Sort columns if the columns of `self` and `other` are not aligned.
.. versionadded:: 0.23.0
.. versionchanged:: 1.0.0
Changed to not sort by default.
Returns
-------
DataFrame
See Also
--------
concat : General function to concatenate DataFrame or Series objects.
Notes
-----
If a list of dict/series is passed and the keys are all contained in
the DataFrame's index, the order of the columns in the resulting
DataFrame will be unchanged.
Iteratively appending rows to a DataFrame can be more computationally
intensive than a single concatenate. A better solution is to append
those rows to a list and then concatenate the list with the original
DataFrame all at once.
Examples
--------
>>> df = pd.DataFrame([[1, 2], [3, 4]], columns=list('AB'))
>>> df
A B
0 1 2
1 3 4
>>> df2 = pd.DataFrame([[5, 6], [7, 8]], columns=list('AB'))
>>> df.append(df2)
A B
0 1 2
1 3 4
0 5 6
1 7 8
With `ignore_index` set to True:
>>> df.append(df2, ignore_index=True)
A B
0 1 2
1 3 4
2 5 6
3 7 8
The following, while not recommended methods for generating DataFrames,
show two ways to generate a DataFrame from multiple data sources.
Less efficient:
>>> df = pd.DataFrame(columns=['A'])
>>> for i in range(5):
... df = df.append({'A': i}, ignore_index=True)
>>> df
A
0 0
1 1
2 2
3 3
4 4
More efficient:
>>> pd.concat([pd.DataFrame([i], columns=['A']) for i in range(5)],
... ignore_index=True)
A
0 0
1 1
2 2
3 3
4 4
"""
if isinstance(other, (Series, dict)):
if isinstance(other, dict):
if not ignore_index:
raise TypeError("Can only append a dict if ignore_index=True")
other = Series(other)
if other.name is None and not ignore_index:
raise TypeError(
"Can only append a Series if ignore_index=True "
"or if the Series has a name"
)
index = Index([other.name], name=self.index.name)
idx_diff = other.index.difference(self.columns)
try:
combined_columns = self.columns.append(idx_diff)
except TypeError:
combined_columns = self.columns.astype(object).append(idx_diff)
other = (
other.reindex(combined_columns, copy=False)
.to_frame()
.T.infer_objects()
.rename_axis(index.names, copy=False)
)
if not self.columns.equals(combined_columns):
self = self.reindex(columns=combined_columns)
elif isinstance(other, list):
if not other:
pass
elif not isinstance(other[0], DataFrame):
other = DataFrame(other)
if (self.columns.get_indexer(other.columns) >= 0).all():
other = other.reindex(columns=self.columns)
from pandas.core.reshape.concat import concat
if isinstance(other, (list, tuple)):
to_concat = [self, *other]
else:
to_concat = [self, other]
return concat(
to_concat,
ignore_index=ignore_index,
verify_integrity=verify_integrity,
sort=sort,
)
def join(
self, other, on=None, how="left", lsuffix="", rsuffix="", sort=False
) -> "DataFrame":
"""
Join columns of another DataFrame.
Join columns with `other` DataFrame either on index or on a key
column. Efficiently join multiple DataFrame objects by index at once by
passing a list.
Parameters
----------
other : DataFrame, Series, or list of DataFrame
Index should be similar to one of the columns in this one. If a
Series is passed, its name attribute must be set, and that will be
used as the column name in the resulting joined DataFrame.
on : str, list of str, or array-like, optional
Column or index level name(s) in the caller to join on the index
in `other`, otherwise joins index-on-index. If multiple
values given, the `other` DataFrame must have a MultiIndex. Can
pass an array as the join key if it is not already contained in
the calling DataFrame. Like an Excel VLOOKUP operation.
how : {'left', 'right', 'outer', 'inner'}, default 'left'
How to handle the operation of the two objects.
* left: use calling frame's index (or column if on is specified)
* right: use `other`'s index.
* outer: form union of calling frame's index (or column if on is
specified) with `other`'s index, and sort it.
lexicographically.
* inner: form intersection of calling frame's index (or column if
on is specified) with `other`'s index, preserving the order
of the calling's one.
lsuffix : str, default ''
Suffix to use from left frame's overlapping columns.
rsuffix : str, default ''
Suffix to use from right frame's overlapping columns.
sort : bool, default False
Order result DataFrame lexicographically by the join key. If False,
the order of the join key depends on the join type (how keyword).
Returns
-------
DataFrame
A dataframe containing columns from both the caller and `other`.
See Also
--------
DataFrame.merge : For column(s)-on-columns(s) operations.
Notes
-----
Parameters `on`, `lsuffix`, and `rsuffix` are not supported when
passing a list of `DataFrame` objects.
Support for specifying index levels as the `on` parameter was added
in version 0.23.0.
Examples
--------
>>> df = pd.DataFrame({'key': ['K0', 'K1', 'K2', 'K3', 'K4', 'K5'],
... 'A': ['A0', 'A1', 'A2', 'A3', 'A4', 'A5']})
>>> df
key A
0 K0 A0
1 K1 A1
2 K2 A2
3 K3 A3
4 K4 A4
5 K5 A5
>>> other = pd.DataFrame({'key': ['K0', 'K1', 'K2'],
... 'B': ['B0', 'B1', 'B2']})
>>> other
key B
0 K0 B0
1 K1 B1
2 K2 B2
Join DataFrames using their indexes.
>>> df.join(other, lsuffix='_caller', rsuffix='_other')
key_caller A key_other B
0 K0 A0 K0 B0
1 K1 A1 K1 B1
2 K2 A2 K2 B2
3 K3 A3 NaN NaN
4 K4 A4 NaN NaN
5 K5 A5 NaN NaN
If we want to join using the key columns, we need to set key to be
the index in both `df` and `other`. The joined DataFrame will have
key as its index.
>>> df.set_index('key').join(other.set_index('key'))
A B
key
K0 A0 B0
K1 A1 B1
K2 A2 B2
K3 A3 NaN
K4 A4 NaN
K5 A5 NaN
Another option to join using the key columns is to use the `on`
parameter. DataFrame.join always uses `other`'s index but we can use
any column in `df`. This method preserves the original DataFrame's
index in the result.
>>> df.join(other.set_index('key'), on='key')
key A B
0 K0 A0 B0
1 K1 A1 B1
2 K2 A2 B2
3 K3 A3 NaN
4 K4 A4 NaN
5 K5 A5 NaN
"""
return self._join_compat(
other, on=on, how=how, lsuffix=lsuffix, rsuffix=rsuffix, sort=sort
)
def _join_compat(
self, other, on=None, how="left", lsuffix="", rsuffix="", sort=False
):
from pandas.core.reshape.merge import merge
from pandas.core.reshape.concat import concat
if isinstance(other, Series):
if other.name is None:
raise ValueError("Other Series must have a name")
other = DataFrame({other.name: other})
if isinstance(other, DataFrame):
return merge(
self,
other,
left_on=on,
how=how,
left_index=on is None,
right_index=True,
suffixes=(lsuffix, rsuffix),
sort=sort,
)
else:
if on is not None:
raise ValueError(
"Joining multiple DataFrames only supported for joining on index"
)
frames = [self] + list(other)
can_concat = all(df.index.is_unique for df in frames)
# join indexes only using concat
if can_concat:
if how == "left":
res = concat(
frames, axis=1, join="outer", verify_integrity=True, sort=sort
)
return res.reindex(self.index, copy=False)
else:
return concat(
frames, axis=1, join=how, verify_integrity=True, sort=sort
)
joined = frames[0]
for frame in frames[1:]:
joined = merge(
joined, frame, how=how, left_index=True, right_index=True
)
return joined
@Substitution("")
@Appender(_merge_doc, indents=2)
def merge(
self,
right,
how="inner",
on=None,
left_on=None,
right_on=None,
left_index=False,
right_index=False,
sort=False,
suffixes=("_x", "_y"),
copy=True,
indicator=False,
validate=None,
) -> "DataFrame":
from pandas.core.reshape.merge import merge
return merge(
self,
right,
how=how,
on=on,
left_on=left_on,
right_on=right_on,
left_index=left_index,
right_index=right_index,
sort=sort,
suffixes=suffixes,
copy=copy,
indicator=indicator,
validate=validate,
)
def round(self, decimals=0, *args, **kwargs) -> "DataFrame":
"""
Round a DataFrame to a variable number of decimal places.
Parameters
----------
decimals : int, dict, Series
Number of decimal places to round each column to. If an int is
given, round each column to the same number of places.
Otherwise dict and Series round to variable numbers of places.
Column names should be in the keys if `decimals` is a
dict-like, or in the index if `decimals` is a Series. Any
columns not included in `decimals` will be left as is. Elements
of `decimals` which are not columns of the input will be
ignored.
*args
Additional keywords have no effect but might be accepted for
compatibility with numpy.
**kwargs
Additional keywords have no effect but might be accepted for
compatibility with numpy.
Returns
-------
DataFrame
A DataFrame with the affected columns rounded to the specified
number of decimal places.
See Also
--------
numpy.around : Round a numpy array to the given number of decimals.
Series.round : Round a Series to the given number of decimals.
Examples
--------
>>> df = pd.DataFrame([(.21, .32), (.01, .67), (.66, .03), (.21, .18)],
... columns=['dogs', 'cats'])
>>> df
dogs cats
0 0.21 0.32
1 0.01 0.67
2 0.66 0.03
3 0.21 0.18
By providing an integer each column is rounded to the same number
of decimal places
>>> df.round(1)
dogs cats
0 0.2 0.3
1 0.0 0.7
2 0.7 0.0
3 0.2 0.2
With a dict, the number of places for specific columns can be
specified with the column names as key and the number of decimal
places as value
>>> df.round({'dogs': 1, 'cats': 0})
dogs cats
0 0.2 0.0
1 0.0 1.0
2 0.7 0.0
3 0.2 0.0
Using a Series, the number of places for specific columns can be
specified with the column names as index and the number of
decimal places as value
>>> decimals = pd.Series([0, 1], index=['cats', 'dogs'])
>>> df.round(decimals)
dogs cats
0 0.2 0.0
1 0.0 1.0
2 0.7 0.0
3 0.2 0.0
"""
from pandas.core.reshape.concat import concat
def _dict_round(df, decimals):
for col, vals in df.items():
try:
yield _series_round(vals, decimals[col])
except KeyError:
yield vals
def _series_round(s, decimals):
if is_integer_dtype(s) or is_float_dtype(s):
return s.round(decimals)
return s
nv.validate_round(args, kwargs)
if isinstance(decimals, (dict, Series)):
if isinstance(decimals, Series):
if not decimals.index.is_unique:
raise ValueError("Index of decimals must be unique")
new_cols = list(_dict_round(self, decimals))
elif is_integer(decimals):
# Dispatch to Series.round
new_cols = [_series_round(v, decimals) for _, v in self.items()]
else:
raise TypeError("decimals must be an integer, a dict-like or a Series")
if len(new_cols) > 0:
return self._constructor(
concat(new_cols, axis=1), index=self.index, columns=self.columns
)
else:
return self
# ----------------------------------------------------------------------
# Statistical methods, etc.
def corr(self, method="pearson", min_periods=1) -> "DataFrame":
"""
Compute pairwise correlation of columns, excluding NA/null values.
Parameters
----------
method : {'pearson', 'kendall', 'spearman'} or callable
Method of correlation:
* pearson : standard correlation coefficient
* kendall : Kendall Tau correlation coefficient
* spearman : Spearman rank correlation
* callable: callable with input two 1d ndarrays
and returning a float. Note that the returned matrix from corr
will have 1 along the diagonals and will be symmetric
regardless of the callable's behavior.
.. versionadded:: 0.24.0
min_periods : int, optional
Minimum number of observations required per pair of columns
to have a valid result. Currently only available for Pearson
and Spearman correlation.
Returns
-------
DataFrame
Correlation matrix.
See Also
--------
DataFrame.corrwith
Series.corr
Examples
--------
>>> def histogram_intersection(a, b):
... v = np.minimum(a, b).sum().round(decimals=1)
... return v
>>> df = pd.DataFrame([(.2, .3), (.0, .6), (.6, .0), (.2, .1)],
... columns=['dogs', 'cats'])
>>> df.corr(method=histogram_intersection)
dogs cats
dogs 1.0 0.3
cats 0.3 1.0
"""
numeric_df = self._get_numeric_data()
cols = numeric_df.columns
idx = cols.copy()
mat = numeric_df.values
if method == "pearson":
correl = libalgos.nancorr(ensure_float64(mat), minp=min_periods)
elif method == "spearman":
correl = libalgos.nancorr_spearman(ensure_float64(mat), minp=min_periods)
elif method == "kendall" or callable(method):
if min_periods is None:
min_periods = 1
mat = ensure_float64(mat).T
corrf = nanops.get_corr_func(method)
K = len(cols)
correl = np.empty((K, K), dtype=float)
mask = np.isfinite(mat)
for i, ac in enumerate(mat):
for j, bc in enumerate(mat):
if i > j:
continue
valid = mask[i] & mask[j]
if valid.sum() < min_periods:
c = np.nan
elif i == j:
c = 1.0
elif not valid.all():
c = corrf(ac[valid], bc[valid])
else:
c = corrf(ac, bc)
correl[i, j] = c
correl[j, i] = c
else:
raise ValueError(
"method must be either 'pearson', "
"'spearman', 'kendall', or a callable, "
f"'{method}' was supplied"
)
return self._constructor(correl, index=idx, columns=cols)
def cov(self, min_periods=None) -> "DataFrame":
"""
Compute pairwise covariance of columns, excluding NA/null values.
Compute the pairwise covariance among the series of a DataFrame.
The returned data frame is the `covariance matrix
<https://en.wikipedia.org/wiki/Covariance_matrix>`__ of the columns
of the DataFrame.
Both NA and null values are automatically excluded from the
calculation. (See the note below about bias from missing values.)
A threshold can be set for the minimum number of
observations for each value created. Comparisons with observations
below this threshold will be returned as ``NaN``.
This method is generally used for the analysis of time series data to
understand the relationship between different measures
across time.
Parameters
----------
min_periods : int, optional
Minimum number of observations required per pair of columns
to have a valid result.
Returns
-------
DataFrame
The covariance matrix of the series of the DataFrame.
See Also
--------
Series.cov : Compute covariance with another Series.
core.window.EWM.cov: Exponential weighted sample covariance.
core.window.Expanding.cov : Expanding sample covariance.
core.window.Rolling.cov : Rolling sample covariance.
Notes
-----
Returns the covariance matrix of the DataFrame's time series.
The covariance is normalized by N-1.
For DataFrames that have Series that are missing data (assuming that
data is `missing at random
<https://en.wikipedia.org/wiki/Missing_data#Missing_at_random>`__)
the returned covariance matrix will be an unbiased estimate
of the variance and covariance between the member Series.
However, for many applications this estimate may not be acceptable
because the estimate covariance matrix is not guaranteed to be positive
semi-definite. This could lead to estimate correlations having
absolute values which are greater than one, and/or a non-invertible
covariance matrix. See `Estimation of covariance matrices
<http://en.wikipedia.org/w/index.php?title=Estimation_of_covariance_
matrices>`__ for more details.
Examples
--------
>>> df = pd.DataFrame([(1, 2), (0, 3), (2, 0), (1, 1)],
... columns=['dogs', 'cats'])
>>> df.cov()
dogs cats
dogs 0.666667 -1.000000
cats -1.000000 1.666667
>>> np.random.seed(42)
>>> df = pd.DataFrame(np.random.randn(1000, 5),
... columns=['a', 'b', 'c', 'd', 'e'])
>>> df.cov()
a b c d e
a 0.998438 -0.020161 0.059277 -0.008943 0.014144
b -0.020161 1.059352 -0.008543 -0.024738 0.009826
c 0.059277 -0.008543 1.010670 -0.001486 -0.000271
d -0.008943 -0.024738 -0.001486 0.921297 -0.013692
e 0.014144 0.009826 -0.000271 -0.013692 0.977795
**Minimum number of periods**
This method also supports an optional ``min_periods`` keyword
that specifies the required minimum number of non-NA observations for
each column pair in order to have a valid result:
>>> np.random.seed(42)
>>> df = pd.DataFrame(np.random.randn(20, 3),
... columns=['a', 'b', 'c'])
>>> df.loc[df.index[:5], 'a'] = np.nan
>>> df.loc[df.index[5:10], 'b'] = np.nan
>>> df.cov(min_periods=12)
a b c
a 0.316741 NaN -0.150812
b NaN 1.248003 0.191417
c -0.150812 0.191417 0.895202
"""
numeric_df = self._get_numeric_data()
cols = numeric_df.columns
idx = cols.copy()
mat = numeric_df.values
if notna(mat).all():
if min_periods is not None and min_periods > len(mat):
baseCov = np.empty((mat.shape[1], mat.shape[1]))
baseCov.fill(np.nan)
else:
baseCov = np.cov(mat.T)
baseCov = baseCov.reshape((len(cols), len(cols)))
else:
baseCov = libalgos.nancorr(ensure_float64(mat), cov=True, minp=min_periods)
return self._constructor(baseCov, index=idx, columns=cols)
def corrwith(self, other, axis=0, drop=False, method="pearson") -> Series:
"""
Compute pairwise correlation.
Pairwise correlation is computed between rows or columns of
DataFrame with rows or columns of Series or DataFrame. DataFrames
are first aligned along both axes before computing the
correlations.
Parameters
----------
other : DataFrame, Series
Object with which to compute correlations.
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to use. 0 or 'index' to compute column-wise, 1 or 'columns' for
row-wise.
drop : bool, default False
Drop missing indices from result.
method : {'pearson', 'kendall', 'spearman'} or callable
Method of correlation:
* pearson : standard correlation coefficient
* kendall : Kendall Tau correlation coefficient
* spearman : Spearman rank correlation
* callable: callable with input two 1d ndarrays
and returning a float.
.. versionadded:: 0.24.0
Returns
-------
Series
Pairwise correlations.
See Also
--------
DataFrame.corr
"""
axis = self._get_axis_number(axis)
this = self._get_numeric_data()
if isinstance(other, Series):
return this.apply(lambda x: other.corr(x, method=method), axis=axis)
other = other._get_numeric_data()
left, right = this.align(other, join="inner", copy=False)
if axis == 1:
left = left.T
right = right.T
if method == "pearson":
# mask missing values
left = left + right * 0
right = right + left * 0
# demeaned data
ldem = left - left.mean()
rdem = right - right.mean()
num = (ldem * rdem).sum()
dom = (left.count() - 1) * left.std() * right.std()
correl = num / dom
elif method in ["kendall", "spearman"] or callable(method):
def c(x):
return nanops.nancorr(x[0], x[1], method=method)
correl = Series(
map(c, zip(left.values.T, right.values.T)), index=left.columns
)
else:
raise ValueError(
f"Invalid method {method} was passed, "
"valid methods are: 'pearson', 'kendall', "
"'spearman', or callable"
)
if not drop:
# Find non-matching labels along the given axis
# and append missing correlations (GH 22375)
raxis = 1 if axis == 0 else 0
result_index = this._get_axis(raxis).union(other._get_axis(raxis))
idx_diff = result_index.difference(correl.index)
if len(idx_diff) > 0:
correl = correl.append(Series([np.nan] * len(idx_diff), index=idx_diff))
return correl
# ----------------------------------------------------------------------
# ndarray-like stats methods
def count(self, axis=0, level=None, numeric_only=False):
"""
Count non-NA cells for each column or row.
The values `None`, `NaN`, `NaT`, and optionally `numpy.inf` (depending
on `pandas.options.mode.use_inf_as_na`) are considered NA.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
If 0 or 'index' counts are generated for each column.
If 1 or 'columns' counts are generated for each **row**.
level : int or str, optional
If the axis is a `MultiIndex` (hierarchical), count along a
particular `level`, collapsing into a `DataFrame`.
A `str` specifies the level name.
numeric_only : bool, default False
Include only `float`, `int` or `boolean` data.
Returns
-------
Series or DataFrame
For each column/row the number of non-NA/null entries.
If `level` is specified returns a `DataFrame`.
See Also
--------
Series.count: Number of non-NA elements in a Series.
DataFrame.shape: Number of DataFrame rows and columns (including NA
elements).
DataFrame.isna: Boolean same-sized DataFrame showing places of NA
elements.
Examples
--------
Constructing DataFrame from a dictionary:
>>> df = pd.DataFrame({"Person":
... ["John", "Myla", "Lewis", "John", "Myla"],
... "Age": [24., np.nan, 21., 33, 26],
... "Single": [False, True, True, True, False]})
>>> df
Person Age Single
0 John 24.0 False
1 Myla NaN True
2 Lewis 21.0 True
3 John 33.0 True
4 Myla 26.0 False
Notice the uncounted NA values:
>>> df.count()
Person 5
Age 4
Single 5
dtype: int64
Counts for each **row**:
>>> df.count(axis='columns')
0 3
1 2
2 3
3 3
4 3
dtype: int64
Counts for one level of a `MultiIndex`:
>>> df.set_index(["Person", "Single"]).count(level="Person")
Age
Person
John 2
Lewis 1
Myla 1
"""
axis = self._get_axis_number(axis)
if level is not None:
return self._count_level(level, axis=axis, numeric_only=numeric_only)
if numeric_only:
frame = self._get_numeric_data()
else:
frame = self
# GH #423
if len(frame._get_axis(axis)) == 0:
result = Series(0, index=frame._get_agg_axis(axis))
else:
if frame._is_mixed_type or frame._data.any_extension_types:
# the or any_extension_types is really only hit for single-
# column frames with an extension array
result = notna(frame).sum(axis=axis)
else:
# GH13407
series_counts = notna(frame).sum(axis=axis)
counts = series_counts.values
result = Series(counts, index=frame._get_agg_axis(axis))
return result.astype("int64")
def _count_level(self, level, axis=0, numeric_only=False):
if numeric_only:
frame = self._get_numeric_data()
else:
frame = self
count_axis = frame._get_axis(axis)
agg_axis = frame._get_agg_axis(axis)
if not isinstance(count_axis, ABCMultiIndex):
raise TypeError(
f"Can only count levels on hierarchical {self._get_axis_name(axis)}."
)
if frame._is_mixed_type:
# Since we have mixed types, calling notna(frame.values) might
# upcast everything to object
mask = notna(frame).values
else:
# But use the speedup when we have homogeneous dtypes
mask = notna(frame.values)
if axis == 1:
# We're transposing the mask rather than frame to avoid potential
# upcasts to object, which induces a ~20x slowdown
mask = mask.T
if isinstance(level, str):
level = count_axis._get_level_number(level)
level_name = count_axis._names[level]
level_index = count_axis.levels[level]._shallow_copy(name=level_name)
level_codes = ensure_int64(count_axis.codes[level])
counts = lib.count_level_2d(mask, level_codes, len(level_index), axis=0)
result = DataFrame(counts, index=level_index, columns=agg_axis)
if axis == 1:
# Undo our earlier transpose
return result.T
else:
return result
def _reduce(
self, op, name, axis=0, skipna=True, numeric_only=None, filter_type=None, **kwds
):
if axis is None and filter_type == "bool":
labels = None
constructor = None
else:
# TODO: Make other agg func handle axis=None properly
axis = self._get_axis_number(axis)
labels = self._get_agg_axis(axis)
constructor = self._constructor
def f(x):
return op(x, axis=axis, skipna=skipna, **kwds)
def _get_data(axis_matters):
if filter_type is None or filter_type == "numeric":
data = self._get_numeric_data()
elif filter_type == "bool":
if axis_matters:
# GH#25101, GH#24434
data = self._get_bool_data() if axis == 0 else self
else:
data = self._get_bool_data()
else: # pragma: no cover
msg = (
f"Generating numeric_only data with filter_type {filter_type} "
"not supported."
)
raise NotImplementedError(msg)
return data
if numeric_only is not None and axis in [0, 1]:
df = self
if numeric_only is True:
df = _get_data(axis_matters=True)
if axis == 1:
df = df.T
axis = 0
out_dtype = "bool" if filter_type == "bool" else None
# After possibly _get_data and transposing, we are now in the
# simple case where we can use BlockManager._reduce
res = df._data.reduce(op, axis=1, skipna=skipna, **kwds)
assert isinstance(res, dict)
if len(res):
assert len(res) == max(list(res.keys())) + 1, res.keys()
out = df._constructor_sliced(res, index=range(len(res)), dtype=out_dtype)
out.index = df.columns
return out
if numeric_only is None:
values = self.values
try:
result = f(values)
if filter_type == "bool" and is_object_dtype(values) and axis is None:
# work around https://github.com/numpy/numpy/issues/10489
# TODO: combine with hasattr(result, 'dtype') further down
# hard since we don't have `values` down there.
result = np.bool_(result)
except TypeError:
# e.g. in nanops trying to convert strs to float
# try by-column first
if filter_type is None and axis == 0:
# this can end up with a non-reduction
# but not always. if the types are mixed
# with datelike then need to make sure a series
# we only end up here if we have not specified
# numeric_only and yet we have tried a
# column-by-column reduction, where we have mixed type.
# So let's just do what we can
from pandas.core.apply import frame_apply
opa = frame_apply(
self, func=f, result_type="expand", ignore_failures=True
)
result = opa.get_result()
if result.ndim == self.ndim:
result = result.iloc[0]
return result
# TODO: why doesnt axis matter here?
data = _get_data(axis_matters=False)
with np.errstate(all="ignore"):
result = f(data.values)
labels = data._get_agg_axis(axis)
else:
if numeric_only:
data = _get_data(axis_matters=True)
values = data.values
labels = data._get_agg_axis(axis)
else:
values = self.values
result = f(values)
if hasattr(result, "dtype") and is_object_dtype(result.dtype):
try:
if filter_type is None or filter_type == "numeric":
result = result.astype(np.float64)
elif filter_type == "bool" and notna(result).all():
result = result.astype(np.bool_)
except (ValueError, TypeError):
# try to coerce to the original dtypes item by item if we can
if axis == 0:
result = coerce_to_dtypes(result, self.dtypes)
if constructor is not None:
result = Series(result, index=labels)
return result
def nunique(self, axis=0, dropna=True) -> Series:
"""
Count distinct observations over requested axis.
Return Series with number of distinct observations. Can ignore NaN
values.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to use. 0 or 'index' for row-wise, 1 or 'columns' for
column-wise.
dropna : bool, default True
Don't include NaN in the counts.
Returns
-------
Series
See Also
--------
Series.nunique: Method nunique for Series.
DataFrame.count: Count non-NA cells for each column or row.
Examples
--------
>>> df = pd.DataFrame({'A': [1, 2, 3], 'B': [1, 1, 1]})
>>> df.nunique()
A 3
B 1
dtype: int64
>>> df.nunique(axis=1)
0 1
1 2
2 2
dtype: int64
"""
return self.apply(Series.nunique, axis=axis, dropna=dropna)
def idxmin(self, axis=0, skipna=True) -> Series:
"""
Return index of first occurrence of minimum over requested axis.
NA/null values are excluded.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to use. 0 or 'index' for row-wise, 1 or 'columns' for column-wise.
skipna : bool, default True
Exclude NA/null values. If an entire row/column is NA, the result
will be NA.
Returns
-------
Series
Indexes of minima along the specified axis.
Raises
------
ValueError
* If the row/column is empty
See Also
--------
Series.idxmin
Notes
-----
This method is the DataFrame version of ``ndarray.argmin``.
"""
axis = self._get_axis_number(axis)
indices = nanops.nanargmin(self.values, axis=axis, skipna=skipna)
index = self._get_axis(axis)
result = [index[i] if i >= 0 else np.nan for i in indices]
return Series(result, index=self._get_agg_axis(axis))
def idxmax(self, axis=0, skipna=True) -> Series:
"""
Return index of first occurrence of maximum over requested axis.
NA/null values are excluded.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to use. 0 or 'index' for row-wise, 1 or 'columns' for column-wise.
skipna : bool, default True
Exclude NA/null values. If an entire row/column is NA, the result
will be NA.
Returns
-------
Series
Indexes of maxima along the specified axis.
Raises
------
ValueError
* If the row/column is empty
See Also
--------
Series.idxmax
Notes
-----
This method is the DataFrame version of ``ndarray.argmax``.
"""
axis = self._get_axis_number(axis)
indices = nanops.nanargmax(self.values, axis=axis, skipna=skipna)
index = self._get_axis(axis)
result = [index[i] if i >= 0 else np.nan for i in indices]
return Series(result, index=self._get_agg_axis(axis))
def _get_agg_axis(self, axis_num):
"""
Let's be explicit about this.
"""
if axis_num == 0:
return self.columns
elif axis_num == 1:
return self.index
else:
raise ValueError(f"Axis must be 0 or 1 (got {repr(axis_num)})")
def mode(self, axis=0, numeric_only=False, dropna=True) -> "DataFrame":
"""
Get the mode(s) of each element along the selected axis.
The mode of a set of values is the value that appears most often.
It can be multiple values.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to iterate over while searching for the mode:
* 0 or 'index' : get mode of each column
* 1 or 'columns' : get mode of each row.
numeric_only : bool, default False
If True, only apply to numeric columns.
dropna : bool, default True
Don't consider counts of NaN/NaT.
.. versionadded:: 0.24.0
Returns
-------
DataFrame
The modes of each column or row.
See Also
--------
Series.mode : Return the highest frequency value in a Series.
Series.value_counts : Return the counts of values in a Series.
Examples
--------
>>> df = pd.DataFrame([('bird', 2, 2),
... ('mammal', 4, np.nan),
... ('arthropod', 8, 0),
... ('bird', 2, np.nan)],
... index=('falcon', 'horse', 'spider', 'ostrich'),
... columns=('species', 'legs', 'wings'))
>>> df
species legs wings
falcon bird 2 2.0
horse mammal 4 NaN
spider arthropod 8 0.0
ostrich bird 2 NaN
By default, missing values are not considered, and the mode of wings
are both 0 and 2. The second row of species and legs contains ``NaN``,
because they have only one mode, but the DataFrame has two rows.
>>> df.mode()
species legs wings
0 bird 2.0 0.0
1 NaN NaN 2.0
Setting ``dropna=False`` ``NaN`` values are considered and they can be
the mode (like for wings).
>>> df.mode(dropna=False)
species legs wings
0 bird 2 NaN
Setting ``numeric_only=True``, only the mode of numeric columns is
computed, and columns of other types are ignored.
>>> df.mode(numeric_only=True)
legs wings
0 2.0 0.0
1 NaN 2.0
To compute the mode over columns and not rows, use the axis parameter:
>>> df.mode(axis='columns', numeric_only=True)
0 1
falcon 2.0 NaN
horse 4.0 NaN
spider 0.0 8.0
ostrich 2.0 NaN
"""
data = self if not numeric_only else self._get_numeric_data()
def f(s):
return s.mode(dropna=dropna)
return data.apply(f, axis=axis)
def quantile(self, q=0.5, axis=0, numeric_only=True, interpolation="linear"):
"""
Return values at the given quantile over requested axis.
Parameters
----------
q : float or array-like, default 0.5 (50% quantile)
Value between 0 <= q <= 1, the quantile(s) to compute.
axis : {0, 1, 'index', 'columns'} (default 0)
Equals 0 or 'index' for row-wise, 1 or 'columns' for column-wise.
numeric_only : bool, default True
If False, the quantile of datetime and timedelta data will be
computed as well.
interpolation : {'linear', 'lower', 'higher', 'midpoint', 'nearest'}
This optional parameter specifies the interpolation method to use,
when the desired quantile lies between two data points `i` and `j`:
* linear: `i + (j - i) * fraction`, where `fraction` is the
fractional part of the index surrounded by `i` and `j`.
* lower: `i`.
* higher: `j`.
* nearest: `i` or `j` whichever is nearest.
* midpoint: (`i` + `j`) / 2.
Returns
-------
Series or DataFrame
If ``q`` is an array, a DataFrame will be returned where the
index is ``q``, the columns are the columns of self, and the
values are the quantiles.
If ``q`` is a float, a Series will be returned where the
index is the columns of self and the values are the quantiles.
See Also
--------
core.window.Rolling.quantile: Rolling quantile.
numpy.percentile: Numpy function to compute the percentile.
Examples
--------
>>> df = pd.DataFrame(np.array([[1, 1], [2, 10], [3, 100], [4, 100]]),
... columns=['a', 'b'])
>>> df.quantile(.1)
a 1.3
b 3.7
Name: 0.1, dtype: float64
>>> df.quantile([.1, .5])
a b
0.1 1.3 3.7
0.5 2.5 55.0
Specifying `numeric_only=False` will also compute the quantile of
datetime and timedelta data.
>>> df = pd.DataFrame({'A': [1, 2],
... 'B': [pd.Timestamp('2010'),
... pd.Timestamp('2011')],
... 'C': [pd.Timedelta('1 days'),
... pd.Timedelta('2 days')]})
>>> df.quantile(0.5, numeric_only=False)
A 1.5
B 2010-07-02 12:00:00
C 1 days 12:00:00
Name: 0.5, dtype: object
"""
validate_percentile(q)
data = self._get_numeric_data() if numeric_only else self
axis = self._get_axis_number(axis)
is_transposed = axis == 1
if is_transposed:
data = data.T
if len(data.columns) == 0:
# GH#23925 _get_numeric_data may have dropped all columns
cols = Index([], name=self.columns.name)
if is_list_like(q):
return self._constructor([], index=q, columns=cols)
return self._constructor_sliced([], index=cols, name=q, dtype=np.float64)
result = data._data.quantile(
qs=q, axis=1, interpolation=interpolation, transposed=is_transposed
)
if result.ndim == 2:
result = self._constructor(result)
else:
result = self._constructor_sliced(result, name=q)
if is_transposed:
result = result.T
return result
def to_timestamp(self, freq=None, how="start", axis=0, copy=True) -> "DataFrame":
"""
Cast to DatetimeIndex of timestamps, at *beginning* of period.
Parameters
----------
freq : str, default frequency of PeriodIndex
Desired frequency.
how : {'s', 'e', 'start', 'end'}
Convention for converting period to timestamp; start of period
vs. end.
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to convert (the index by default).
copy : bool, default True
If False then underlying input data is not copied.
Returns
-------
DataFrame with DatetimeIndex
"""
new_data = self._data
if copy:
new_data = new_data.copy()
axis = self._get_axis_number(axis)
if axis == 0:
new_data.set_axis(1, self.index.to_timestamp(freq=freq, how=how))
elif axis == 1:
new_data.set_axis(0, self.columns.to_timestamp(freq=freq, how=how))
else: # pragma: no cover
raise AssertionError(f"Axis must be 0 or 1. Got {axis}")
return self._constructor(new_data)
def to_period(self, freq=None, axis=0, copy=True) -> "DataFrame":
"""
Convert DataFrame from DatetimeIndex to PeriodIndex.
Convert DataFrame from DatetimeIndex to PeriodIndex with desired
frequency (inferred from index if not passed).
Parameters
----------
freq : str, default
Frequency of the PeriodIndex.
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to convert (the index by default).
copy : bool, default True
If False then underlying input data is not copied.
Returns
-------
TimeSeries with PeriodIndex
"""
new_data = self._data
if copy:
new_data = new_data.copy()
axis = self._get_axis_number(axis)
if axis == 0:
new_data.set_axis(1, self.index.to_period(freq=freq))
elif axis == 1:
new_data.set_axis(0, self.columns.to_period(freq=freq))
else: # pragma: no cover
raise AssertionError(f"Axis must be 0 or 1. Got {axis}")
return self._constructor(new_data)
def isin(self, values) -> "DataFrame":
"""
Whether each element in the DataFrame is contained in values.
Parameters
----------
values : iterable, Series, DataFrame or dict
The result will only be true at a location if all the
labels match. If `values` is a Series, that's the index. If
`values` is a dict, the keys must be the column names,
which must match. If `values` is a DataFrame,
then both the index and column labels must match.
Returns
-------
DataFrame
DataFrame of booleans showing whether each element in the DataFrame
is contained in values.
See Also
--------
DataFrame.eq: Equality test for DataFrame.
Series.isin: Equivalent method on Series.
Series.str.contains: Test if pattern or regex is contained within a
string of a Series or Index.
Examples
--------
>>> df = pd.DataFrame({'num_legs': [2, 4], 'num_wings': [2, 0]},
... index=['falcon', 'dog'])
>>> df
num_legs num_wings
falcon 2 2
dog 4 0
When ``values`` is a list check whether every value in the DataFrame
is present in the list (which animals have 0 or 2 legs or wings)
>>> df.isin([0, 2])
num_legs num_wings
falcon True True
dog False True
When ``values`` is a dict, we can pass values to check for each
column separately:
>>> df.isin({'num_wings': [0, 3]})
num_legs num_wings
falcon False False
dog False True
When ``values`` is a Series or DataFrame the index and column must
match. Note that 'falcon' does not match based on the number of legs
in df2.
>>> other = pd.DataFrame({'num_legs': [8, 2], 'num_wings': [0, 2]},
... index=['spider', 'falcon'])
>>> df.isin(other)
num_legs num_wings
falcon True True
dog False False
"""
if isinstance(values, dict):
from pandas.core.reshape.concat import concat
values = collections.defaultdict(list, values)
return self._ensure_type(
concat(
(
self.iloc[:, [i]].isin(values[col])
for i, col in enumerate(self.columns)
),
axis=1,
)
)
elif isinstance(values, Series):
if not values.index.is_unique:
raise ValueError("cannot compute isin with a duplicate axis.")
return self.eq(values.reindex_like(self), axis="index")
elif isinstance(values, DataFrame):
if not (values.columns.is_unique and values.index.is_unique):
raise ValueError("cannot compute isin with a duplicate axis.")
return self.eq(values.reindex_like(self))
else:
if not is_list_like(values):
raise TypeError(
"only list-like or dict-like objects are allowed "
"to be passed to DataFrame.isin(), "
f"you passed a '{type(values).__name__}'"
)
return DataFrame(
algorithms.isin(self.values.ravel(), values).reshape(self.shape),
self.index,
self.columns,
)
# ----------------------------------------------------------------------
# Add plotting methods to DataFrame
plot = CachedAccessor("plot", pandas.plotting.PlotAccessor)
hist = pandas.plotting.hist_frame
boxplot = pandas.plotting.boxplot_frame
sparse = CachedAccessor("sparse", SparseFrameAccessor)
DataFrame._setup_axes(
["index", "columns"],
docs={
"index": "The index (row labels) of the DataFrame.",
"columns": "The column labels of the DataFrame.",
},
)
DataFrame._add_numeric_operations()
DataFrame._add_series_or_dataframe_operations()
ops.add_flex_arithmetic_methods(DataFrame)
ops.add_special_arithmetic_methods(DataFrame)
def _from_nested_dict(data):
# TODO: this should be seriously cythonized
new_data = {}
for index, s in data.items():
for col, v in s.items():
new_data[col] = new_data.get(col, {})
new_data[col][index] = v
return new_data
def _put_str(s, space):
return str(s)[:space].ljust(space)
"""
DataFrame
---------
An efficient 2D container for potentially mixed-type time series or other
labeled data series.
Similar to its R counterpart, data.frame, except providing automatic data
alignment and a host of useful data manipulation methods having to do with the
labeling information
"""
import collections
from collections import abc
from io import StringIO
import itertools
import sys
from textwrap import dedent
from typing import (
IO,
TYPE_CHECKING,
Any,
FrozenSet,
Hashable,
Iterable,
List,
Optional,
Sequence,
Set,
Tuple,
Type,
Union,
cast,
)
import warnings
import numpy as np
import numpy.ma as ma
from pandas._config import get_option
from pandas._libs import algos as libalgos, lib
from pandas._typing import Axes, Axis, Dtype, FilePathOrBuffer, Level, Renamer
from pandas.compat import PY37
from pandas.compat._optional import import_optional_dependency
from pandas.compat.numpy import function as nv
from pandas.util._decorators import (
Appender,
Substitution,
deprecate_kwarg,
rewrite_axis_style_signature,
)
from pandas.util._validators import (
validate_axis_style_args,
validate_bool_kwarg,
validate_percentile,
)
from pandas.core.dtypes.cast import (
cast_scalar_to_array,
coerce_to_dtypes,
find_common_type,
infer_dtype_from_scalar,
invalidate_string_dtypes,
maybe_cast_to_datetime,
maybe_convert_platform,
maybe_downcast_to_dtype,
maybe_infer_to_datetimelike,
maybe_upcast,
maybe_upcast_putmask,
)
from pandas.core.dtypes.common import (
ensure_float64,
ensure_int64,
ensure_platform_int,
infer_dtype_from_object,
is_bool_dtype,
is_dict_like,
is_dtype_equal,
is_extension_array_dtype,
is_float_dtype,
is_hashable,
is_integer,
is_integer_dtype,
is_iterator,
is_list_like,
is_named_tuple,
is_object_dtype,
is_scalar,
is_sequence,
needs_i8_conversion,
)
from pandas.core.dtypes.generic import (
ABCDataFrame,
ABCIndexClass,
ABCMultiIndex,
ABCSeries,
)
from pandas.core.dtypes.missing import isna, notna
from pandas.core import algorithms, common as com, nanops, ops
from pandas.core.accessor import CachedAccessor
from pandas.core.arrays import Categorical, ExtensionArray
from pandas.core.arrays.datetimelike import DatetimeLikeArrayMixin as DatetimeLikeArray
from pandas.core.arrays.sparse import SparseFrameAccessor
from pandas.core.generic import NDFrame, _shared_docs
from pandas.core.indexes import base as ibase
from pandas.core.indexes.api import Index, ensure_index, ensure_index_from_sequences
from pandas.core.indexes.datetimes import DatetimeIndex
from pandas.core.indexes.multi import maybe_droplevels
from pandas.core.indexes.period import PeriodIndex
from pandas.core.indexing import check_bool_indexer, convert_to_index_sliceable
from pandas.core.internals import BlockManager
from pandas.core.internals.construction import (
arrays_to_mgr,
get_names_from_index,
init_dict,
init_ndarray,
masked_rec_array_to_mgr,
reorder_arrays,
sanitize_index,
to_arrays,
)
from pandas.core.ops.missing import dispatch_fill_zeros
from pandas.core.series import Series
from pandas.io.common import get_filepath_or_buffer
from pandas.io.formats import console, format as fmt
from pandas.io.formats.printing import pprint_thing
import pandas.plotting
if TYPE_CHECKING:
from pandas.core.groupby.generic import DataFrameGroupBy
from pandas.io.formats.style import Styler
# ---------------------------------------------------------------------
# Docstring templates
_shared_doc_kwargs = dict(
axes="index, columns",
klass="DataFrame",
axes_single_arg="{0 or 'index', 1 or 'columns'}",
axis="""axis : {0 or 'index', 1 or 'columns'}, default 0
If 0 or 'index': apply function to each column.
If 1 or 'columns': apply function to each row.""",
optional_by="""
by : str or list of str
Name or list of names to sort by.
- if `axis` is 0 or `'index'` then `by` may contain index
levels and/or column labels.
- if `axis` is 1 or `'columns'` then `by` may contain column
levels and/or index labels.
.. versionchanged:: 0.23.0
Allow specifying index or column level names.""",
versionadded_to_excel="",
optional_labels="""labels : array-like, optional
New labels / index to conform the axis specified by 'axis' to.""",
optional_axis="""axis : int or str, optional
Axis to target. Can be either the axis name ('index', 'columns')
or number (0, 1).""",
)
_numeric_only_doc = """numeric_only : boolean, default None
Include only float, int, boolean data. If None, will attempt to use
everything, then use only numeric data
"""
_merge_doc = """
Merge DataFrame or named Series objects with a database-style join.
The join is done on columns or indexes. If joining columns on
columns, the DataFrame indexes *will be ignored*. Otherwise if joining indexes
on indexes or indexes on a column or columns, the index will be passed on.
Parameters
----------%s
right : DataFrame or named Series
Object to merge with.
how : {'left', 'right', 'outer', 'inner'}, default 'inner'
Type of merge to be performed.
* left: use only keys from left frame, similar to a SQL left outer join;
preserve key order.
* right: use only keys from right frame, similar to a SQL right outer join;
preserve key order.
* outer: use union of keys from both frames, similar to a SQL full outer
join; sort keys lexicographically.
* inner: use intersection of keys from both frames, similar to a SQL inner
join; preserve the order of the left keys.
on : label or list
Column or index level names to join on. These must be found in both
DataFrames. If `on` is None and not merging on indexes then this defaults
to the intersection of the columns in both DataFrames.
left_on : label or list, or array-like
Column or index level names to join on in the left DataFrame. Can also
be an array or list of arrays of the length of the left DataFrame.
These arrays are treated as if they are columns.
right_on : label or list, or array-like
Column or index level names to join on in the right DataFrame. Can also
be an array or list of arrays of the length of the right DataFrame.
These arrays are treated as if they are columns.
left_index : bool, default False
Use the index from the left DataFrame as the join key(s). If it is a
MultiIndex, the number of keys in the other DataFrame (either the index
or a number of columns) must match the number of levels.
right_index : bool, default False
Use the index from the right DataFrame as the join key. Same caveats as
left_index.
sort : bool, default False
Sort the join keys lexicographically in the result DataFrame. If False,
the order of the join keys depends on the join type (how keyword).
suffixes : tuple of (str, str), default ('_x', '_y')
Suffix to apply to overlapping column names in the left and right
side, respectively. To raise an exception on overlapping columns use
(False, False).
copy : bool, default True
If False, avoid copy if possible.
indicator : bool or str, default False
If True, adds a column to output DataFrame called "_merge" with
information on the source of each row.
If string, column with information on source of each row will be added to
output DataFrame, and column will be named value of string.
Information column is Categorical-type and takes on a value of "left_only"
for observations whose merge key only appears in 'left' DataFrame,
"right_only" for observations whose merge key only appears in 'right'
DataFrame, and "both" if the observation's merge key is found in both.
validate : str, optional
If specified, checks if merge is of specified type.
* "one_to_one" or "1:1": check if merge keys are unique in both
left and right datasets.
* "one_to_many" or "1:m": check if merge keys are unique in left
dataset.
* "many_to_one" or "m:1": check if merge keys are unique in right
dataset.
* "many_to_many" or "m:m": allowed, but does not result in checks.
.. versionadded:: 0.21.0
Returns
-------
DataFrame
A DataFrame of the two merged objects.
See Also
--------
merge_ordered : Merge with optional filling/interpolation.
merge_asof : Merge on nearest keys.
DataFrame.join : Similar method using indices.
Notes
-----
Support for specifying index levels as the `on`, `left_on`, and
`right_on` parameters was added in version 0.23.0
Support for merging named Series objects was added in version 0.24.0
Examples
--------
>>> df1 = pd.DataFrame({'lkey': ['foo', 'bar', 'baz', 'foo'],
... 'value': [1, 2, 3, 5]})
>>> df2 = pd.DataFrame({'rkey': ['foo', 'bar', 'baz', 'foo'],
... 'value': [5, 6, 7, 8]})
>>> df1
lkey value
0 foo 1
1 bar 2
2 baz 3
3 foo 5
>>> df2
rkey value
0 foo 5
1 bar 6
2 baz 7
3 foo 8
Merge df1 and df2 on the lkey and rkey columns. The value columns have
the default suffixes, _x and _y, appended.
>>> df1.merge(df2, left_on='lkey', right_on='rkey')
lkey value_x rkey value_y
0 foo 1 foo 5
1 foo 1 foo 8
2 foo 5 foo 5
3 foo 5 foo 8
4 bar 2 bar 6
5 baz 3 baz 7
Merge DataFrames df1 and df2 with specified left and right suffixes
appended to any overlapping columns.
>>> df1.merge(df2, left_on='lkey', right_on='rkey',
... suffixes=('_left', '_right'))
lkey value_left rkey value_right
0 foo 1 foo 5
1 foo 1 foo 8
2 foo 5 foo 5
3 foo 5 foo 8
4 bar 2 bar 6
5 baz 3 baz 7
Merge DataFrames df1 and df2, but raise an exception if the DataFrames have
any overlapping columns.
>>> df1.merge(df2, left_on='lkey', right_on='rkey', suffixes=(False, False))
Traceback (most recent call last):
...
ValueError: columns overlap but no suffix specified:
Index(['value'], dtype='object')
"""
# -----------------------------------------------------------------------
# DataFrame class
class DataFrame(NDFrame):
"""
Two-dimensional, size-mutable, potentially heterogeneous tabular data.
Data structure also contains labeled axes (rows and columns).
Arithmetic operations align on both row and column labels. Can be
thought of as a dict-like container for Series objects. The primary
pandas data structure.
Parameters
----------
data : ndarray (structured or homogeneous), Iterable, dict, or DataFrame
Dict can contain Series, arrays, constants, or list-like objects.
.. versionchanged:: 0.23.0
If data is a dict, column order follows insertion-order for
Python 3.6 and later.
.. versionchanged:: 0.25.0
If data is a list of dicts, column order follows insertion-order
for Python 3.6 and later.
index : Index or array-like
Index to use for resulting frame. Will default to RangeIndex if
no indexing information part of input data and no index provided.
columns : Index or array-like
Column labels to use for resulting frame. Will default to
RangeIndex (0, 1, 2, ..., n) if no column labels are provided.
dtype : dtype, default None
Data type to force. Only a single dtype is allowed. If None, infer.
copy : bool, default False
Copy data from inputs. Only affects DataFrame / 2d ndarray input.
See Also
--------
DataFrame.from_records : Constructor from tuples, also record arrays.
DataFrame.from_dict : From dicts of Series, arrays, or dicts.
read_csv
read_table
read_clipboard
Examples
--------
Constructing DataFrame from a dictionary.
>>> d = {'col1': [1, 2], 'col2': [3, 4]}
>>> df = pd.DataFrame(data=d)
>>> df
col1 col2
0 1 3
1 2 4
Notice that the inferred dtype is int64.
>>> df.dtypes
col1 int64
col2 int64
dtype: object
To enforce a single dtype:
>>> df = pd.DataFrame(data=d, dtype=np.int8)
>>> df.dtypes
col1 int8
col2 int8
dtype: object
Constructing DataFrame from numpy ndarray:
>>> df2 = pd.DataFrame(np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]]),
... columns=['a', 'b', 'c'])
>>> df2
a b c
0 1 2 3
1 4 5 6
2 7 8 9
"""
_typ = "dataframe"
@property
def _constructor(self) -> Type["DataFrame"]:
return DataFrame
_constructor_sliced: Type[Series] = Series
_deprecations: FrozenSet[str] = NDFrame._deprecations | frozenset([])
_accessors: Set[str] = {"sparse"}
@property
def _constructor_expanddim(self):
raise NotImplementedError("Not supported for DataFrames!")
# ----------------------------------------------------------------------
# Constructors
def __init__(
self,
data=None,
index: Optional[Axes] = None,
columns: Optional[Axes] = None,
dtype: Optional[Dtype] = None,
copy: bool = False,
):
if data is None:
data = {}
if dtype is not None:
dtype = self._validate_dtype(dtype)
if isinstance(data, DataFrame):
data = data._data
if isinstance(data, BlockManager):
mgr = self._init_mgr(
data, axes=dict(index=index, columns=columns), dtype=dtype, copy=copy
)
elif isinstance(data, dict):
mgr = init_dict(data, index, columns, dtype=dtype)
elif isinstance(data, ma.MaskedArray):
import numpy.ma.mrecords as mrecords
# masked recarray
if isinstance(data, mrecords.MaskedRecords):
mgr = masked_rec_array_to_mgr(data, index, columns, dtype, copy)
# a masked array
else:
mask = ma.getmaskarray(data)
if mask.any():
data, fill_value = maybe_upcast(data, copy=True)
data.soften_mask() # set hardmask False if it was True
data[mask] = fill_value
else:
data = data.copy()
mgr = init_ndarray(data, index, columns, dtype=dtype, copy=copy)
elif isinstance(data, (np.ndarray, Series, Index)):
if data.dtype.names:
data_columns = list(data.dtype.names)
data = {k: data[k] for k in data_columns}
if columns is None:
columns = data_columns
mgr = init_dict(data, index, columns, dtype=dtype)
elif getattr(data, "name", None) is not None:
mgr = init_dict({data.name: data}, index, columns, dtype=dtype)
else:
mgr = init_ndarray(data, index, columns, dtype=dtype, copy=copy)
# For data is list-like, or Iterable (will consume into list)
elif isinstance(data, abc.Iterable) and not isinstance(data, (str, bytes)):
if not isinstance(data, (abc.Sequence, ExtensionArray)):
data = list(data)
if len(data) > 0:
if is_list_like(data[0]) and getattr(data[0], "ndim", 1) == 1:
if is_named_tuple(data[0]) and columns is None:
columns = data[0]._fields
arrays, columns = to_arrays(data, columns, dtype=dtype)
columns = ensure_index(columns)
# set the index
if index is None:
if isinstance(data[0], Series):
index = get_names_from_index(data)
elif isinstance(data[0], Categorical):
index = ibase.default_index(len(data[0]))
else:
index = ibase.default_index(len(data))
mgr = arrays_to_mgr(arrays, columns, index, columns, dtype=dtype)
else:
mgr = init_ndarray(data, index, columns, dtype=dtype, copy=copy)
else:
mgr = init_dict({}, index, columns, dtype=dtype)
else:
try:
arr = np.array(data, dtype=dtype, copy=copy)
except (ValueError, TypeError) as err:
exc = TypeError(
"DataFrame constructor called with "
f"incompatible data and dtype: {err}"
)
raise exc from err
if arr.ndim == 0 and index is not None and columns is not None:
values = cast_scalar_to_array(
(len(index), len(columns)), data, dtype=dtype
)
mgr = init_ndarray(
values, index, columns, dtype=values.dtype, copy=False
)
else:
raise ValueError("DataFrame constructor not properly called!")
NDFrame.__init__(self, mgr, fastpath=True)
# ----------------------------------------------------------------------
@property
def axes(self) -> List[Index]:
"""
Return a list representing the axes of the DataFrame.
It has the row axis labels and column axis labels as the only members.
They are returned in that order.
Examples
--------
>>> df = pd.DataFrame({'col1': [1, 2], 'col2': [3, 4]})
>>> df.axes
[RangeIndex(start=0, stop=2, step=1), Index(['col1', 'col2'],
dtype='object')]
"""
return [self.index, self.columns]
@property
def shape(self) -> Tuple[int, int]:
"""
Return a tuple representing the dimensionality of the DataFrame.
See Also
--------
ndarray.shape
Examples
--------
>>> df = pd.DataFrame({'col1': [1, 2], 'col2': [3, 4]})
>>> df.shape
(2, 2)
>>> df = pd.DataFrame({'col1': [1, 2], 'col2': [3, 4],
... 'col3': [5, 6]})
>>> df.shape
(2, 3)
"""
return len(self.index), len(self.columns)
@property
def _is_homogeneous_type(self) -> bool:
"""
Whether all the columns in a DataFrame have the same type.
Returns
-------
bool
See Also
--------
Index._is_homogeneous_type : Whether the object has a single
dtype.
MultiIndex._is_homogeneous_type : Whether all the levels of a
MultiIndex have the same dtype.
Examples
--------
>>> DataFrame({"A": [1, 2], "B": [3, 4]})._is_homogeneous_type
True
>>> DataFrame({"A": [1, 2], "B": [3.0, 4.0]})._is_homogeneous_type
False
Items with the same type but different sizes are considered
different types.
>>> DataFrame({
... "A": np.array([1, 2], dtype=np.int32),
... "B": np.array([1, 2], dtype=np.int64)})._is_homogeneous_type
False
"""
if self._data.any_extension_types:
return len({block.dtype for block in self._data.blocks}) == 1
else:
return not self._data.is_mixed_type
# ----------------------------------------------------------------------
# Rendering Methods
def _repr_fits_vertical_(self) -> bool:
"""
Check length against max_rows.
"""
max_rows = get_option("display.max_rows")
return len(self) <= max_rows
def _repr_fits_horizontal_(self, ignore_width: bool = False) -> bool:
"""
Check if full repr fits in horizontal boundaries imposed by the display
options width and max_columns.
In case off non-interactive session, no boundaries apply.
`ignore_width` is here so ipnb+HTML output can behave the way
users expect. display.max_columns remains in effect.
GH3541, GH3573
"""
width, height = console.get_console_size()
max_columns = get_option("display.max_columns")
nb_columns = len(self.columns)
# exceed max columns
if (max_columns and nb_columns > max_columns) or (
(not ignore_width) and width and nb_columns > (width // 2)
):
return False
# used by repr_html under IPython notebook or scripts ignore terminal
# dims
if ignore_width or not console.in_interactive_session():
return True
if get_option("display.width") is not None or console.in_ipython_frontend():
# check at least the column row for excessive width
max_rows = 1
else:
max_rows = get_option("display.max_rows")
# when auto-detecting, so width=None and not in ipython front end
# check whether repr fits horizontal by actually checking
# the width of the rendered repr
buf = StringIO()
# only care about the stuff we'll actually print out
# and to_string on entire frame may be expensive
d = self
if not (max_rows is None): # unlimited rows
# min of two, where one may be None
d = d.iloc[: min(max_rows, len(d))]
else:
return True
d.to_string(buf=buf)
value = buf.getvalue()
repr_width = max(len(l) for l in value.split("\n"))
return repr_width < width
def _info_repr(self) -> bool:
"""
True if the repr should show the info view.
"""
info_repr_option = get_option("display.large_repr") == "info"
return info_repr_option and not (
self._repr_fits_horizontal_() and self._repr_fits_vertical_()
)
def __repr__(self) -> str:
"""
Return a string representation for a particular DataFrame.
"""
buf = StringIO("")
if self._info_repr():
self.info(buf=buf)
return buf.getvalue()
max_rows = get_option("display.max_rows")
min_rows = get_option("display.min_rows")
max_cols = get_option("display.max_columns")
max_colwidth = get_option("display.max_colwidth")
show_dimensions = get_option("display.show_dimensions")
if get_option("display.expand_frame_repr"):
width, _ = console.get_console_size()
else:
width = None
self.to_string(
buf=buf,
max_rows=max_rows,
min_rows=min_rows,
max_cols=max_cols,
line_width=width,
max_colwidth=max_colwidth,
show_dimensions=show_dimensions,
)
return buf.getvalue()
def _repr_html_(self) -> Optional[str]:
"""
Return a html representation for a particular DataFrame.
Mainly for IPython notebook.
"""
if self._info_repr():
buf = StringIO("")
self.info(buf=buf)
# need to escape the <class>, should be the first line.
val = buf.getvalue().replace("<", r"<", 1)
val = val.replace(">", r">", 1)
return "<pre>" + val + "</pre>"
if get_option("display.notebook_repr_html"):
max_rows = get_option("display.max_rows")
min_rows = get_option("display.min_rows")
max_cols = get_option("display.max_columns")
show_dimensions = get_option("display.show_dimensions")
formatter = fmt.DataFrameFormatter(
self,
columns=None,
col_space=None,
na_rep="NaN",
formatters=None,
float_format=None,
sparsify=None,
justify=None,
index_names=True,
header=True,
index=True,
bold_rows=True,
escape=True,
max_rows=max_rows,
min_rows=min_rows,
max_cols=max_cols,
show_dimensions=show_dimensions,
decimal=".",
table_id=None,
render_links=False,
)
return formatter.to_html(notebook=True)
else:
return None
@Substitution(
header_type="bool or sequence",
header="Write out the column names. If a list of strings "
"is given, it is assumed to be aliases for the "
"column names",
col_space_type="int",
col_space="The minimum width of each column",
)
@Substitution(shared_params=fmt.common_docstring, returns=fmt.return_docstring)
def to_string(
self,
buf: Optional[FilePathOrBuffer[str]] = None,
columns: Optional[Sequence[str]] = None,
col_space: Optional[int] = None,
header: Union[bool, Sequence[str]] = True,
index: bool = True,
na_rep: str = "NaN",
formatters: Optional[fmt.formatters_type] = None,
float_format: Optional[fmt.float_format_type] = None,
sparsify: Optional[bool] = None,
index_names: bool = True,
justify: Optional[str] = None,
max_rows: Optional[int] = None,
min_rows: Optional[int] = None,
max_cols: Optional[int] = None,
show_dimensions: bool = False,
decimal: str = ".",
line_width: Optional[int] = None,
max_colwidth: Optional[int] = None,
encoding: Optional[str] = None,
) -> Optional[str]:
"""
Render a DataFrame to a console-friendly tabular output.
%(shared_params)s
line_width : int, optional
Width to wrap a line in characters.
max_colwidth : int, optional
Max width to truncate each column in characters. By default, no limit.
.. versionadded:: 1.0.0
encoding : str, default "utf-8"
Set character encoding.
.. versionadded:: 1.0
%(returns)s
See Also
--------
to_html : Convert DataFrame to HTML.
Examples
--------
>>> d = {'col1': [1, 2, 3], 'col2': [4, 5, 6]}
>>> df = pd.DataFrame(d)
>>> print(df.to_string())
col1 col2
0 1 4
1 2 5
2 3 6
"""
from pandas import option_context
with option_context("display.max_colwidth", max_colwidth):
formatter = fmt.DataFrameFormatter(
self,
columns=columns,
col_space=col_space,
na_rep=na_rep,
formatters=formatters,
float_format=float_format,
sparsify=sparsify,
justify=justify,
index_names=index_names,
header=header,
index=index,
min_rows=min_rows,
max_rows=max_rows,
max_cols=max_cols,
show_dimensions=show_dimensions,
decimal=decimal,
line_width=line_width,
)
return formatter.to_string(buf=buf, encoding=encoding)
# ----------------------------------------------------------------------
@property
def style(self) -> "Styler":
"""
Returns a Styler object.
Contains methods for building a styled HTML representation of the DataFrame.
a styled HTML representation fo the DataFrame.
See Also
--------
io.formats.style.Styler
"""
from pandas.io.formats.style import Styler
return Styler(self)
_shared_docs[
"items"
] = r"""
Iterate over (column name, Series) pairs.
Iterates over the DataFrame columns, returning a tuple with
the column name and the content as a Series.
Yields
------
label : object
The column names for the DataFrame being iterated over.
content : Series
The column entries belonging to each label, as a Series.
See Also
--------
DataFrame.iterrows : Iterate over DataFrame rows as
(index, Series) pairs.
DataFrame.itertuples : Iterate over DataFrame rows as namedtuples
of the values.
Examples
--------
>>> df = pd.DataFrame({'species': ['bear', 'bear', 'marsupial'],
... 'population': [1864, 22000, 80000]},
... index=['panda', 'polar', 'koala'])
>>> df
species population
panda bear 1864
polar bear 22000
koala marsupial 80000
>>> for label, content in df.items():
... print('label:', label)
... print('content:', content, sep='\n')
...
label: species
content:
panda bear
polar bear
koala marsupial
Name: species, dtype: object
label: population
content:
panda 1864
polar 22000
koala 80000
Name: population, dtype: int64
"""
@Appender(_shared_docs["items"])
def items(self) -> Iterable[Tuple[Optional[Hashable], Series]]:
if self.columns.is_unique and hasattr(self, "_item_cache"):
for k in self.columns:
yield k, self._get_item_cache(k)
else:
for i, k in enumerate(self.columns):
yield k, self._ixs(i, axis=1)
@Appender(_shared_docs["items"])
def iteritems(self) -> Iterable[Tuple[Optional[Hashable], Series]]:
yield from self.items()
def iterrows(self) -> Iterable[Tuple[Optional[Hashable], Series]]:
"""
Iterate over DataFrame rows as (index, Series) pairs.
Yields
------
index : label or tuple of label
The index of the row. A tuple for a `MultiIndex`.
data : Series
The data of the row as a Series.
it : generator
A generator that iterates over the rows of the frame.
See Also
--------
DataFrame.itertuples : Iterate over DataFrame rows as namedtuples of the values.
DataFrame.items : Iterate over (column name, Series) pairs.
Notes
-----
1. Because ``iterrows`` returns a Series for each row,
it does **not** preserve dtypes across the rows (dtypes are
preserved across columns for DataFrames). For example,
>>> df = pd.DataFrame([[1, 1.5]], columns=['int', 'float'])
>>> row = next(df.iterrows())[1]
>>> row
int 1.0
float 1.5
Name: 0, dtype: float64
>>> print(row['int'].dtype)
float64
>>> print(df['int'].dtype)
int64
To preserve dtypes while iterating over the rows, it is better
to use :meth:`itertuples` which returns namedtuples of the values
and which is generally faster than ``iterrows``.
2. You should **never modify** something you are iterating over.
This is not guaranteed to work in all cases. Depending on the
data types, the iterator returns a copy and not a view, and writing
to it will have no effect.
"""
columns = self.columns
klass = self._constructor_sliced
for k, v in zip(self.index, self.values):
s = klass(v, index=columns, name=k)
yield k, s
def itertuples(self, index=True, name="Pandas"):
"""
Iterate over DataFrame rows as namedtuples.
Parameters
----------
index : bool, default True
If True, return the index as the first element of the tuple.
name : str or None, default "Pandas"
The name of the returned namedtuples or None to return regular
tuples.
Returns
-------
iterator
An object to iterate over namedtuples for each row in the
DataFrame with the first field possibly being the index and
following fields being the column values.
See Also
--------
DataFrame.iterrows : Iterate over DataFrame rows as (index, Series)
pairs.
DataFrame.items : Iterate over (column name, Series) pairs.
Notes
-----
The column names will be renamed to positional names if they are
invalid Python identifiers, repeated, or start with an underscore.
On python versions < 3.7 regular tuples are returned for DataFrames
with a large number of columns (>254).
Examples
--------
>>> df = pd.DataFrame({'num_legs': [4, 2], 'num_wings': [0, 2]},
... index=['dog', 'hawk'])
>>> df
num_legs num_wings
dog 4 0
hawk 2 2
>>> for row in df.itertuples():
... print(row)
...
Pandas(Index='dog', num_legs=4, num_wings=0)
Pandas(Index='hawk', num_legs=2, num_wings=2)
By setting the `index` parameter to False we can remove the index
as the first element of the tuple:
>>> for row in df.itertuples(index=False):
... print(row)
...
Pandas(num_legs=4, num_wings=0)
Pandas(num_legs=2, num_wings=2)
With the `name` parameter set we set a custom name for the yielded
namedtuples:
>>> for row in df.itertuples(name='Animal'):
... print(row)
...
Animal(Index='dog', num_legs=4, num_wings=0)
Animal(Index='hawk', num_legs=2, num_wings=2)
"""
arrays = []
fields = list(self.columns)
if index:
arrays.append(self.index)
fields.insert(0, "Index")
# use integer indexing because of possible duplicate column names
arrays.extend(self.iloc[:, k] for k in range(len(self.columns)))
# Python versions before 3.7 support at most 255 arguments to constructors
can_return_named_tuples = PY37 or len(self.columns) + index < 255
if name is not None and can_return_named_tuples:
itertuple = collections.namedtuple(name, fields, rename=True)
return map(itertuple._make, zip(*arrays))
# fallback to regular tuples
return zip(*arrays)
def __len__(self) -> int:
"""
Returns length of info axis, but here we use the index.
"""
return len(self.index)
def dot(self, other):
"""
Compute the matrix multiplication between the DataFrame and other.
This method computes the matrix product between the DataFrame and the
values of an other Series, DataFrame or a numpy array.
It can also be called using ``self @ other`` in Python >= 3.5.
Parameters
----------
other : Series, DataFrame or array-like
The other object to compute the matrix product with.
Returns
-------
Series or DataFrame
If other is a Series, return the matrix product between self and
other as a Serie. If other is a DataFrame or a numpy.array, return
the matrix product of self and other in a DataFrame of a np.array.
See Also
--------
Series.dot: Similar method for Series.
Notes
-----
The dimensions of DataFrame and other must be compatible in order to
compute the matrix multiplication. In addition, the column names of
DataFrame and the index of other must contain the same values, as they
will be aligned prior to the multiplication.
The dot method for Series computes the inner product, instead of the
matrix product here.
Examples
--------
Here we multiply a DataFrame with a Series.
>>> df = pd.DataFrame([[0, 1, -2, -1], [1, 1, 1, 1]])
>>> s = pd.Series([1, 1, 2, 1])
>>> df.dot(s)
0 -4
1 5
dtype: int64
Here we multiply a DataFrame with another DataFrame.
>>> other = pd.DataFrame([[0, 1], [1, 2], [-1, -1], [2, 0]])
>>> df.dot(other)
0 1
0 1 4
1 2 2
Note that the dot method give the same result as @
>>> df @ other
0 1
0 1 4
1 2 2
The dot method works also if other is an np.array.
>>> arr = np.array([[0, 1], [1, 2], [-1, -1], [2, 0]])
>>> df.dot(arr)
0 1
0 1 4
1 2 2
Note how shuffling of the objects does not change the result.
>>> s2 = s.reindex([1, 0, 2, 3])
>>> df.dot(s2)
0 -4
1 5
dtype: int64
"""
if isinstance(other, (Series, DataFrame)):
common = self.columns.union(other.index)
if len(common) > len(self.columns) or len(common) > len(other.index):
raise ValueError("matrices are not aligned")
left = self.reindex(columns=common, copy=False)
right = other.reindex(index=common, copy=False)
lvals = left.values
rvals = right.values
else:
left = self
lvals = self.values
rvals = np.asarray(other)
if lvals.shape[1] != rvals.shape[0]:
raise ValueError(
f"Dot product shape mismatch, {lvals.shape} vs {rvals.shape}"
)
if isinstance(other, DataFrame):
return self._constructor(
np.dot(lvals, rvals), index=left.index, columns=other.columns
)
elif isinstance(other, Series):
return Series(np.dot(lvals, rvals), index=left.index)
elif isinstance(rvals, (np.ndarray, Index)):
result = np.dot(lvals, rvals)
if result.ndim == 2:
return self._constructor(result, index=left.index)
else:
return Series(result, index=left.index)
else: # pragma: no cover
raise TypeError(f"unsupported type: {type(other)}")
def __matmul__(self, other):
"""
Matrix multiplication using binary `@` operator in Python>=3.5.
"""
return self.dot(other)
def __rmatmul__(self, other):
"""
Matrix multiplication using binary `@` operator in Python>=3.5.
"""
return self.T.dot(np.transpose(other)).T
# ----------------------------------------------------------------------
# IO methods (to / from other formats)
@classmethod
def from_dict(cls, data, orient="columns", dtype=None, columns=None) -> "DataFrame":
"""
Construct DataFrame from dict of array-like or dicts.
Creates DataFrame object from dictionary by columns or by index
allowing dtype specification.
Parameters
----------
data : dict
Of the form {field : array-like} or {field : dict}.
orient : {'columns', 'index'}, default 'columns'
The "orientation" of the data. If the keys of the passed dict
should be the columns of the resulting DataFrame, pass 'columns'
(default). Otherwise if the keys should be rows, pass 'index'.
dtype : dtype, default None
Data type to force, otherwise infer.
columns : list, default None
Column labels to use when ``orient='index'``. Raises a ValueError
if used with ``orient='columns'``.
.. versionadded:: 0.23.0
Returns
-------
DataFrame
See Also
--------
DataFrame.from_records : DataFrame from ndarray (structured
dtype), list of tuples, dict, or DataFrame.
DataFrame : DataFrame object creation using constructor.
Examples
--------
By default the keys of the dict become the DataFrame columns:
>>> data = {'col_1': [3, 2, 1, 0], 'col_2': ['a', 'b', 'c', 'd']}
>>> pd.DataFrame.from_dict(data)
col_1 col_2
0 3 a
1 2 b
2 1 c
3 0 d
Specify ``orient='index'`` to create the DataFrame using dictionary
keys as rows:
>>> data = {'row_1': [3, 2, 1, 0], 'row_2': ['a', 'b', 'c', 'd']}
>>> pd.DataFrame.from_dict(data, orient='index')
0 1 2 3
row_1 3 2 1 0
row_2 a b c d
When using the 'index' orientation, the column names can be
specified manually:
>>> pd.DataFrame.from_dict(data, orient='index',
... columns=['A', 'B', 'C', 'D'])
A B C D
row_1 3 2 1 0
row_2 a b c d
"""
index = None
orient = orient.lower()
if orient == "index":
if len(data) > 0:
# TODO speed up Series case
if isinstance(list(data.values())[0], (Series, dict)):
data = _from_nested_dict(data)
else:
data, index = list(data.values()), list(data.keys())
elif orient == "columns":
if columns is not None:
raise ValueError("cannot use columns parameter with orient='columns'")
else: # pragma: no cover
raise ValueError("only recognize index or columns for orient")
return cls(data, index=index, columns=columns, dtype=dtype)
def to_numpy(self, dtype=None, copy=False) -> np.ndarray:
"""
Convert the DataFrame to a NumPy array.
.. versionadded:: 0.24.0
By default, the dtype of the returned array will be the common NumPy
dtype of all types in the DataFrame. For example, if the dtypes are
``float16`` and ``float32``, the results dtype will be ``float32``.
This may require copying data and coercing values, which may be
expensive.
Parameters
----------
dtype : str or numpy.dtype, optional
The dtype to pass to :meth:`numpy.asarray`.
copy : bool, default False
Whether to ensure that the returned value is a not a view on
another array. Note that ``copy=False`` does not *ensure* that
``to_numpy()`` is no-copy. Rather, ``copy=True`` ensure that
a copy is made, even if not strictly necessary.
Returns
-------
numpy.ndarray
See Also
--------
Series.to_numpy : Similar method for Series.
Examples
--------
>>> pd.DataFrame({"A": [1, 2], "B": [3, 4]}).to_numpy()
array([[1, 3],
[2, 4]])
With heterogeneous data, the lowest common type will have to
be used.
>>> df = pd.DataFrame({"A": [1, 2], "B": [3.0, 4.5]})
>>> df.to_numpy()
array([[1. , 3. ],
[2. , 4.5]])
For a mix of numeric and non-numeric types, the output array will
have object dtype.
>>> df['C'] = pd.date_range('2000', periods=2)
>>> df.to_numpy()
array([[1, 3.0, Timestamp('2000-01-01 00:00:00')],
[2, 4.5, Timestamp('2000-01-02 00:00:00')]], dtype=object)
"""
result = np.array(self.values, dtype=dtype, copy=copy)
return result
def to_dict(self, orient="dict", into=dict):
"""
Convert the DataFrame to a dictionary.
The type of the key-value pairs can be customized with the parameters
(see below).
Parameters
----------
orient : str {'dict', 'list', 'series', 'split', 'records', 'index'}
Determines the type of the values of the dictionary.
- 'dict' (default) : dict like {column -> {index -> value}}
- 'list' : dict like {column -> [values]}
- 'series' : dict like {column -> Series(values)}
- 'split' : dict like
{'index' -> [index], 'columns' -> [columns], 'data' -> [values]}
- 'records' : list like
[{column -> value}, ... , {column -> value}]
- 'index' : dict like {index -> {column -> value}}
Abbreviations are allowed. `s` indicates `series` and `sp`
indicates `split`.
into : class, default dict
The collections.abc.Mapping subclass used for all Mappings
in the return value. Can be the actual class or an empty
instance of the mapping type you want. If you want a
collections.defaultdict, you must pass it initialized.
.. versionadded:: 0.21.0
Returns
-------
dict, list or collections.abc.Mapping
Return a collections.abc.Mapping object representing the DataFrame.
The resulting transformation depends on the `orient` parameter.
See Also
--------
DataFrame.from_dict: Create a DataFrame from a dictionary.
DataFrame.to_json: Convert a DataFrame to JSON format.
Examples
--------
>>> df = pd.DataFrame({'col1': [1, 2],
... 'col2': [0.5, 0.75]},
... index=['row1', 'row2'])
>>> df
col1 col2
row1 1 0.50
row2 2 0.75
>>> df.to_dict()
{'col1': {'row1': 1, 'row2': 2}, 'col2': {'row1': 0.5, 'row2': 0.75}}
You can specify the return orientation.
>>> df.to_dict('series')
{'col1': row1 1
row2 2
Name: col1, dtype: int64,
'col2': row1 0.50
row2 0.75
Name: col2, dtype: float64}
>>> df.to_dict('split')
{'index': ['row1', 'row2'], 'columns': ['col1', 'col2'],
'data': [[1, 0.5], [2, 0.75]]}
>>> df.to_dict('records')
[{'col1': 1, 'col2': 0.5}, {'col1': 2, 'col2': 0.75}]
>>> df.to_dict('index')
{'row1': {'col1': 1, 'col2': 0.5}, 'row2': {'col1': 2, 'col2': 0.75}}
You can also specify the mapping type.
>>> from collections import OrderedDict, defaultdict
>>> df.to_dict(into=OrderedDict)
OrderedDict([('col1', OrderedDict([('row1', 1), ('row2', 2)])),
('col2', OrderedDict([('row1', 0.5), ('row2', 0.75)]))])
If you want a `defaultdict`, you need to initialize it:
>>> dd = defaultdict(list)
>>> df.to_dict('records', into=dd)
[defaultdict(<class 'list'>, {'col1': 1, 'col2': 0.5}),
defaultdict(<class 'list'>, {'col1': 2, 'col2': 0.75})]
"""
if not self.columns.is_unique:
warnings.warn(
"DataFrame columns are not unique, some columns will be omitted.",
UserWarning,
stacklevel=2,
)
# GH16122
into_c = com.standardize_mapping(into)
if orient.lower().startswith("d"):
return into_c((k, v.to_dict(into)) for k, v in self.items())
elif orient.lower().startswith("l"):
return into_c((k, v.tolist()) for k, v in self.items())
elif orient.lower().startswith("sp"):
return into_c(
(
("index", self.index.tolist()),
("columns", self.columns.tolist()),
(
"data",
[
list(map(com.maybe_box_datetimelike, t))
for t in self.itertuples(index=False, name=None)
],
),
)
)
elif orient.lower().startswith("s"):
return into_c((k, com.maybe_box_datetimelike(v)) for k, v in self.items())
elif orient.lower().startswith("r"):
columns = self.columns.tolist()
rows = (
dict(zip(columns, row))
for row in self.itertuples(index=False, name=None)
)
return [
into_c((k, com.maybe_box_datetimelike(v)) for k, v in row.items())
for row in rows
]
elif orient.lower().startswith("i"):
if not self.index.is_unique:
raise ValueError("DataFrame index must be unique for orient='index'.")
return into_c(
(t[0], dict(zip(self.columns, t[1:])))
for t in self.itertuples(name=None)
)
else:
raise ValueError(f"orient '{orient}' not understood")
def to_gbq(
self,
destination_table,
project_id=None,
chunksize=None,
reauth=False,
if_exists="fail",
auth_local_webserver=False,
table_schema=None,
location=None,
progress_bar=True,
credentials=None,
) -> None:
"""
Write a DataFrame to a Google BigQuery table.
This function requires the `pandas-gbq package
<https://pandas-gbq.readthedocs.io>`__.
See the `How to authenticate with Google BigQuery
<https://pandas-gbq.readthedocs.io/en/latest/howto/authentication.html>`__
guide for authentication instructions.
Parameters
----------
destination_table : str
Name of table to be written, in the form ``dataset.tablename``.
project_id : str, optional
Google BigQuery Account project ID. Optional when available from
the environment.
chunksize : int, optional
Number of rows to be inserted in each chunk from the dataframe.
Set to ``None`` to load the whole dataframe at once.
reauth : bool, default False
Force Google BigQuery to re-authenticate the user. This is useful
if multiple accounts are used.
if_exists : str, default 'fail'
Behavior when the destination table exists. Value can be one of:
``'fail'``
If table exists raise pandas_gbq.gbq.TableCreationError.
``'replace'``
If table exists, drop it, recreate it, and insert data.
``'append'``
If table exists, insert data. Create if does not exist.
auth_local_webserver : bool, default False
Use the `local webserver flow`_ instead of the `console flow`_
when getting user credentials.
.. _local webserver flow:
http://google-auth-oauthlib.readthedocs.io/en/latest/reference/google_auth_oauthlib.flow.html#google_auth_oauthlib.flow.InstalledAppFlow.run_local_server
.. _console flow:
http://google-auth-oauthlib.readthedocs.io/en/latest/reference/google_auth_oauthlib.flow.html#google_auth_oauthlib.flow.InstalledAppFlow.run_console
*New in version 0.2.0 of pandas-gbq*.
table_schema : list of dicts, optional
List of BigQuery table fields to which according DataFrame
columns conform to, e.g. ``[{'name': 'col1', 'type':
'STRING'},...]``. If schema is not provided, it will be
generated according to dtypes of DataFrame columns. See
BigQuery API documentation on available names of a field.
*New in version 0.3.1 of pandas-gbq*.
location : str, optional
Location where the load job should run. See the `BigQuery locations
documentation
<https://cloud.google.com/bigquery/docs/dataset-locations>`__ for a
list of available locations. The location must match that of the
target dataset.
*New in version 0.5.0 of pandas-gbq*.
progress_bar : bool, default True
Use the library `tqdm` to show the progress bar for the upload,
chunk by chunk.
*New in version 0.5.0 of pandas-gbq*.
credentials : google.auth.credentials.Credentials, optional
Credentials for accessing Google APIs. Use this parameter to
override default credentials, such as to use Compute Engine
:class:`google.auth.compute_engine.Credentials` or Service
Account :class:`google.oauth2.service_account.Credentials`
directly.
*New in version 0.8.0 of pandas-gbq*.
.. versionadded:: 0.24.0
See Also
--------
pandas_gbq.to_gbq : This function in the pandas-gbq library.
read_gbq : Read a DataFrame from Google BigQuery.
"""
from pandas.io import gbq
gbq.to_gbq(
self,
destination_table,
project_id=project_id,
chunksize=chunksize,
reauth=reauth,
if_exists=if_exists,
auth_local_webserver=auth_local_webserver,
table_schema=table_schema,
location=location,
progress_bar=progress_bar,
credentials=credentials,
)
@classmethod
def from_records(
cls,
data,
index=None,
exclude=None,
columns=None,
coerce_float=False,
nrows=None,
) -> "DataFrame":
"""
Convert structured or record ndarray to DataFrame.
Parameters
----------
data : ndarray (structured dtype), list of tuples, dict, or DataFrame
index : str, list of fields, array-like
Field of array to use as the index, alternately a specific set of
input labels to use.
exclude : sequence, default None
Columns or fields to exclude.
columns : sequence, default None
Column names to use. If the passed data do not have names
associated with them, this argument provides names for the
columns. Otherwise this argument indicates the order of the columns
in the result (any names not found in the data will become all-NA
columns).
coerce_float : bool, default False
Attempt to convert values of non-string, non-numeric objects (like
decimal.Decimal) to floating point, useful for SQL result sets.
nrows : int, default None
Number of rows to read if data is an iterator.
Returns
-------
DataFrame
"""
# Make a copy of the input columns so we can modify it
if columns is not None:
columns = ensure_index(columns)
if is_iterator(data):
if nrows == 0:
return cls()
try:
first_row = next(data)
except StopIteration:
return cls(index=index, columns=columns)
dtype = None
if hasattr(first_row, "dtype") and first_row.dtype.names:
dtype = first_row.dtype
values = [first_row]
if nrows is None:
values += data
else:
values.extend(itertools.islice(data, nrows - 1))
if dtype is not None:
data = np.array(values, dtype=dtype)
else:
data = values
if isinstance(data, dict):
if columns is None:
columns = arr_columns = ensure_index(sorted(data))
arrays = [data[k] for k in columns]
else:
arrays = []
arr_columns = []
for k, v in data.items():
if k in columns:
arr_columns.append(k)
arrays.append(v)
arrays, arr_columns = reorder_arrays(arrays, arr_columns, columns)
elif isinstance(data, (np.ndarray, DataFrame)):
arrays, columns = to_arrays(data, columns)
if columns is not None:
columns = ensure_index(columns)
arr_columns = columns
else:
arrays, arr_columns = to_arrays(data, columns, coerce_float=coerce_float)
arr_columns = ensure_index(arr_columns)
if columns is not None:
columns = ensure_index(columns)
else:
columns = arr_columns
if exclude is None:
exclude = set()
else:
exclude = set(exclude)
result_index = None
if index is not None:
if isinstance(index, str) or not hasattr(index, "__iter__"):
i = columns.get_loc(index)
exclude.add(index)
if len(arrays) > 0:
result_index = Index(arrays[i], name=index)
else:
result_index = Index([], name=index)
else:
try:
index_data = [arrays[arr_columns.get_loc(field)] for field in index]
except (KeyError, TypeError):
# raised by get_loc, see GH#29258
result_index = index
else:
result_index = ensure_index_from_sequences(index_data, names=index)
exclude.update(index)
if any(exclude):
arr_exclude = [x for x in exclude if x in arr_columns]
to_remove = [arr_columns.get_loc(col) for col in arr_exclude]
arrays = [v for i, v in enumerate(arrays) if i not in to_remove]
arr_columns = arr_columns.drop(arr_exclude)
columns = columns.drop(exclude)
mgr = arrays_to_mgr(arrays, arr_columns, result_index, columns)
return cls(mgr)
def to_records(
self, index=True, column_dtypes=None, index_dtypes=None
) -> np.recarray:
"""
Convert DataFrame to a NumPy record array.
Index will be included as the first field of the record array if
requested.
Parameters
----------
index : bool, default True
Include index in resulting record array, stored in 'index'
field or using the index label, if set.
column_dtypes : str, type, dict, default None
.. versionadded:: 0.24.0
If a string or type, the data type to store all columns. If
a dictionary, a mapping of column names and indices (zero-indexed)
to specific data types.
index_dtypes : str, type, dict, default None
.. versionadded:: 0.24.0
If a string or type, the data type to store all index levels. If
a dictionary, a mapping of index level names and indices
(zero-indexed) to specific data types.
This mapping is applied only if `index=True`.
Returns
-------
numpy.recarray
NumPy ndarray with the DataFrame labels as fields and each row
of the DataFrame as entries.
See Also
--------
DataFrame.from_records: Convert structured or record ndarray
to DataFrame.
numpy.recarray: An ndarray that allows field access using
attributes, analogous to typed columns in a
spreadsheet.
Examples
--------
>>> df = pd.DataFrame({'A': [1, 2], 'B': [0.5, 0.75]},
... index=['a', 'b'])
>>> df
A B
a 1 0.50
b 2 0.75
>>> df.to_records()
rec.array([('a', 1, 0.5 ), ('b', 2, 0.75)],
dtype=[('index', 'O'), ('A', '<i8'), ('B', '<f8')])
If the DataFrame index has no label then the recarray field name
is set to 'index'. If the index has a label then this is used as the
field name:
>>> df.index = df.index.rename("I")
>>> df.to_records()
rec.array([('a', 1, 0.5 ), ('b', 2, 0.75)],
dtype=[('I', 'O'), ('A', '<i8'), ('B', '<f8')])
The index can be excluded from the record array:
>>> df.to_records(index=False)
rec.array([(1, 0.5 ), (2, 0.75)],
dtype=[('A', '<i8'), ('B', '<f8')])
Data types can be specified for the columns:
>>> df.to_records(column_dtypes={"A": "int32"})
rec.array([('a', 1, 0.5 ), ('b', 2, 0.75)],
dtype=[('I', 'O'), ('A', '<i4'), ('B', '<f8')])
As well as for the index:
>>> df.to_records(index_dtypes="<S2")
rec.array([(b'a', 1, 0.5 ), (b'b', 2, 0.75)],
dtype=[('I', 'S2'), ('A', '<i8'), ('B', '<f8')])
>>> index_dtypes = f"<S{df.index.str.len().max()}"
>>> df.to_records(index_dtypes=index_dtypes)
rec.array([(b'a', 1, 0.5 ), (b'b', 2, 0.75)],
dtype=[('I', 'S1'), ('A', '<i8'), ('B', '<f8')])
"""
if index:
if isinstance(self.index, ABCMultiIndex):
# array of tuples to numpy cols. copy copy copy
ix_vals = list(map(np.array, zip(*self.index.values)))
else:
ix_vals = [self.index.values]
arrays = ix_vals + [self[c]._internal_get_values() for c in self.columns]
count = 0
index_names = list(self.index.names)
if isinstance(self.index, ABCMultiIndex):
for i, n in enumerate(index_names):
if n is None:
index_names[i] = f"level_{count}"
count += 1
elif index_names[0] is None:
index_names = ["index"]
names = [str(name) for name in itertools.chain(index_names, self.columns)]
else:
arrays = [self[c]._internal_get_values() for c in self.columns]
names = [str(c) for c in self.columns]
index_names = []
index_len = len(index_names)
formats = []
for i, v in enumerate(arrays):
index = i
# When the names and arrays are collected, we
# first collect those in the DataFrame's index,
# followed by those in its columns.
#
# Thus, the total length of the array is:
# len(index_names) + len(DataFrame.columns).
#
# This check allows us to see whether we are
# handling a name / array in the index or column.
if index < index_len:
dtype_mapping = index_dtypes
name = index_names[index]
else:
index -= index_len
dtype_mapping = column_dtypes
name = self.columns[index]
# We have a dictionary, so we get the data type
# associated with the index or column (which can
# be denoted by its name in the DataFrame or its
# position in DataFrame's array of indices or
# columns, whichever is applicable.
if is_dict_like(dtype_mapping):
if name in dtype_mapping:
dtype_mapping = dtype_mapping[name]
elif index in dtype_mapping:
dtype_mapping = dtype_mapping[index]
else:
dtype_mapping = None
# If no mapping can be found, use the array's
# dtype attribute for formatting.
#
# A valid dtype must either be a type or
# string naming a type.
if dtype_mapping is None:
formats.append(v.dtype)
elif isinstance(dtype_mapping, (type, np.dtype, str)):
formats.append(dtype_mapping)
else:
element = "row" if i < index_len else "column"
msg = f"Invalid dtype {dtype_mapping} specified for {element} {name}"
raise ValueError(msg)
return np.rec.fromarrays(arrays, dtype={"names": names, "formats": formats})
@classmethod
def _from_arrays(cls, arrays, columns, index, dtype=None) -> "DataFrame":
mgr = arrays_to_mgr(arrays, columns, index, columns, dtype=dtype)
return cls(mgr)
@deprecate_kwarg(old_arg_name="fname", new_arg_name="path")
def to_stata(
self,
path,
convert_dates=None,
write_index=True,
byteorder=None,
time_stamp=None,
data_label=None,
variable_labels=None,
version=114,
convert_strl=None,
):
"""
Export DataFrame object to Stata dta format.
Writes the DataFrame to a Stata dataset file.
"dta" files contain a Stata dataset.
Parameters
----------
path : str, buffer or path object
String, path object (pathlib.Path or py._path.local.LocalPath) or
object implementing a binary write() function. If using a buffer
then the buffer will not be automatically closed after the file
data has been written.
.. versionchanged:: 1.0.0
Previously this was "fname"
convert_dates : dict
Dictionary mapping columns containing datetime types to stata
internal format to use when writing the dates. Options are 'tc',
'td', 'tm', 'tw', 'th', 'tq', 'ty'. Column can be either an integer
or a name. Datetime columns that do not have a conversion type
specified will be converted to 'tc'. Raises NotImplementedError if
a datetime column has timezone information.
write_index : bool
Write the index to Stata dataset.
byteorder : str
Can be ">", "<", "little", or "big". default is `sys.byteorder`.
time_stamp : datetime
A datetime to use as file creation date. Default is the current
time.
data_label : str, optional
A label for the data set. Must be 80 characters or smaller.
variable_labels : dict
Dictionary containing columns as keys and variable labels as
values. Each label must be 80 characters or smaller.
version : {114, 117, 118, 119, None}, default 114
Version to use in the output dta file. Set to None to let pandas
decide between 118 or 119 formats depending on the number of
columns in the frame. Version 114 can be read by Stata 10 and
later. Version 117 can be read by Stata 13 or later. Version 118
is supported in Stata 14 and later. Version 119 is supported in
Stata 15 and later. Version 114 limits string variables to 244
characters or fewer while versions 117 and later allow strings
with lengths up to 2,000,000 characters. Versions 118 and 119
support Unicode characters, and version 119 supports more than
32,767 variables.
.. versionadded:: 0.23.0
.. versionchanged:: 1.0.0
Added support for formats 118 and 119.
convert_strl : list, optional
List of column names to convert to string columns to Stata StrL
format. Only available if version is 117. Storing strings in the
StrL format can produce smaller dta files if strings have more than
8 characters and values are repeated.
.. versionadded:: 0.23.0
Raises
------
NotImplementedError
* If datetimes contain timezone information
* Column dtype is not representable in Stata
ValueError
* Columns listed in convert_dates are neither datetime64[ns]
or datetime.datetime
* Column listed in convert_dates is not in DataFrame
* Categorical label contains more than 32,000 characters
See Also
--------
read_stata : Import Stata data files.
io.stata.StataWriter : Low-level writer for Stata data files.
io.stata.StataWriter117 : Low-level writer for version 117 files.
Examples
--------
>>> df = pd.DataFrame({'animal': ['falcon', 'parrot', 'falcon',
... 'parrot'],
... 'speed': [350, 18, 361, 15]})
>>> df.to_stata('animals.dta') # doctest: +SKIP
"""
if version not in (114, 117, 118, 119, None):
raise ValueError("Only formats 114, 117, 118 and 119 are supported.")
if version == 114:
if convert_strl is not None:
raise ValueError("strl is not supported in format 114")
from pandas.io.stata import StataWriter as statawriter
elif version == 117:
from pandas.io.stata import StataWriter117 as statawriter
else: # versions 118 and 119
from pandas.io.stata import StataWriterUTF8 as statawriter
kwargs = {}
if version is None or version >= 117:
# strl conversion is only supported >= 117
kwargs["convert_strl"] = convert_strl
if version is None or version >= 118:
# Specifying the version is only supported for UTF8 (118 or 119)
kwargs["version"] = version
writer = statawriter(
path,
self,
convert_dates=convert_dates,
byteorder=byteorder,
time_stamp=time_stamp,
data_label=data_label,
write_index=write_index,
variable_labels=variable_labels,
**kwargs,
)
writer.write_file()
@deprecate_kwarg(old_arg_name="fname", new_arg_name="path")
def to_feather(self, path) -> None:
"""
Write out the binary feather-format for DataFrames.
Parameters
----------
path : str
String file path.
"""
from pandas.io.feather_format import to_feather
to_feather(self, path)
@Appender(
"""
Examples
--------
>>> df = pd.DataFrame(
... data={"animal_1": ["elk", "pig"], "animal_2": ["dog", "quetzal"]}
... )
>>> print(df.to_markdown())
| | animal_1 | animal_2 |
|---:|:-----------|:-----------|
| 0 | elk | dog |
| 1 | pig | quetzal |
"""
)
@Substitution(klass="DataFrame")
@Appender(_shared_docs["to_markdown"])
def to_markdown(
self, buf: Optional[IO[str]] = None, mode: Optional[str] = None, **kwargs
) -> Optional[str]:
kwargs.setdefault("headers", "keys")
kwargs.setdefault("tablefmt", "pipe")
tabulate = import_optional_dependency("tabulate")
result = tabulate.tabulate(self, **kwargs)
if buf is None:
return result
buf, _, _, _ = get_filepath_or_buffer(buf, mode=mode)
assert buf is not None # Help mypy.
buf.writelines(result)
return None
@deprecate_kwarg(old_arg_name="fname", new_arg_name="path")
def to_parquet(
self,
path,
engine="auto",
compression="snappy",
index=None,
partition_cols=None,
**kwargs,
) -> None:
"""
Write a DataFrame to the binary parquet format.
.. versionadded:: 0.21.0
This function writes the dataframe as a `parquet file
<https://parquet.apache.org/>`_. You can choose different parquet
backends, and have the option of compression. See
:ref:`the user guide <io.parquet>` for more details.
Parameters
----------
path : str
File path or Root Directory path. Will be used as Root Directory
path while writing a partitioned dataset.
.. versionchanged:: 1.0.0
Previously this was "fname"
engine : {'auto', 'pyarrow', 'fastparquet'}, default 'auto'
Parquet library to use. If 'auto', then the option
``io.parquet.engine`` is used. The default ``io.parquet.engine``
behavior is to try 'pyarrow', falling back to 'fastparquet' if
'pyarrow' is unavailable.
compression : {'snappy', 'gzip', 'brotli', None}, default 'snappy'
Name of the compression to use. Use ``None`` for no compression.
index : bool, default None
If ``True``, include the dataframe's index(es) in the file output.
If ``False``, they will not be written to the file.
If ``None``, similar to ``True`` the dataframe's index(es)
will be saved. However, instead of being saved as values,
the RangeIndex will be stored as a range in the metadata so it
doesn't require much space and is faster. Other indexes will
be included as columns in the file output.
.. versionadded:: 0.24.0
partition_cols : list, optional, default None
Column names by which to partition the dataset.
Columns are partitioned in the order they are given.
.. versionadded:: 0.24.0
**kwargs
Additional arguments passed to the parquet library. See
:ref:`pandas io <io.parquet>` for more details.
See Also
--------
read_parquet : Read a parquet file.
DataFrame.to_csv : Write a csv file.
DataFrame.to_sql : Write to a sql table.
DataFrame.to_hdf : Write to hdf.
Notes
-----
This function requires either the `fastparquet
<https://pypi.org/project/fastparquet>`_ or `pyarrow
<https://arrow.apache.org/docs/python/>`_ library.
Examples
--------
>>> df = pd.DataFrame(data={'col1': [1, 2], 'col2': [3, 4]})
>>> df.to_parquet('df.parquet.gzip',
... compression='gzip') # doctest: +SKIP
>>> pd.read_parquet('df.parquet.gzip') # doctest: +SKIP
col1 col2
0 1 3
1 2 4
"""
from pandas.io.parquet import to_parquet
to_parquet(
self,
path,
engine,
compression=compression,
index=index,
partition_cols=partition_cols,
**kwargs,
)
@Substitution(
header_type="bool",
header="Whether to print column labels, default True",
col_space_type="str or int",
col_space="The minimum width of each column in CSS length "
"units. An int is assumed to be px units.\n\n"
" .. versionadded:: 0.25.0\n"
" Ability to use str",
)
@Substitution(shared_params=fmt.common_docstring, returns=fmt.return_docstring)
def to_html(
self,
buf=None,
columns=None,
col_space=None,
header=True,
index=True,
na_rep="NaN",
formatters=None,
float_format=None,
sparsify=None,
index_names=True,
justify=None,
max_rows=None,
max_cols=None,
show_dimensions=False,
decimal=".",
bold_rows=True,
classes=None,
escape=True,
notebook=False,
border=None,
table_id=None,
render_links=False,
encoding=None,
):
"""
Render a DataFrame as an HTML table.
%(shared_params)s
bold_rows : bool, default True
Make the row labels bold in the output.
classes : str or list or tuple, default None
CSS class(es) to apply to the resulting html table.
escape : bool, default True
Convert the characters <, >, and & to HTML-safe sequences.
notebook : {True, False}, default False
Whether the generated HTML is for IPython Notebook.
border : int
A ``border=border`` attribute is included in the opening
`<table>` tag. Default ``pd.options.display.html.border``.
encoding : str, default "utf-8"
Set character encoding.
.. versionadded:: 1.0
table_id : str, optional
A css id is included in the opening `<table>` tag if specified.
.. versionadded:: 0.23.0
render_links : bool, default False
Convert URLs to HTML links.
.. versionadded:: 0.24.0
%(returns)s
See Also
--------
to_string : Convert DataFrame to a string.
"""
if justify is not None and justify not in fmt._VALID_JUSTIFY_PARAMETERS:
raise ValueError("Invalid value for justify parameter")
formatter = fmt.DataFrameFormatter(
self,
columns=columns,
col_space=col_space,
na_rep=na_rep,
formatters=formatters,
float_format=float_format,
sparsify=sparsify,
justify=justify,
index_names=index_names,
header=header,
index=index,
bold_rows=bold_rows,
escape=escape,
max_rows=max_rows,
max_cols=max_cols,
show_dimensions=show_dimensions,
decimal=decimal,
table_id=table_id,
render_links=render_links,
)
# TODO: a generic formatter wld b in DataFrameFormatter
return formatter.to_html(
buf=buf,
classes=classes,
notebook=notebook,
border=border,
encoding=encoding,
)
# ----------------------------------------------------------------------
def info(
self, verbose=None, buf=None, max_cols=None, memory_usage=None, null_counts=None
) -> None:
"""
Print a concise summary of a DataFrame.
This method prints information about a DataFrame including
the index dtype and column dtypes, non-null values and memory usage.
Parameters
----------
verbose : bool, optional
Whether to print the full summary. By default, the setting in
``pandas.options.display.max_info_columns`` is followed.
buf : writable buffer, defaults to sys.stdout
Where to send the output. By default, the output is printed to
sys.stdout. Pass a writable buffer if you need to further process
the output.
max_cols : int, optional
When to switch from the verbose to the truncated output. If the
DataFrame has more than `max_cols` columns, the truncated output
is used. By default, the setting in
``pandas.options.display.max_info_columns`` is used.
memory_usage : bool, str, optional
Specifies whether total memory usage of the DataFrame
elements (including the index) should be displayed. By default,
this follows the ``pandas.options.display.memory_usage`` setting.
True always show memory usage. False never shows memory usage.
A value of 'deep' is equivalent to "True with deep introspection".
Memory usage is shown in human-readable units (base-2
representation). Without deep introspection a memory estimation is
made based in column dtype and number of rows assuming values
consume the same memory amount for corresponding dtypes. With deep
memory introspection, a real memory usage calculation is performed
at the cost of computational resources.
null_counts : bool, optional
Whether to show the non-null counts. By default, this is shown
only if the frame is smaller than
``pandas.options.display.max_info_rows`` and
``pandas.options.display.max_info_columns``. A value of True always
shows the counts, and False never shows the counts.
Returns
-------
None
This method prints a summary of a DataFrame and returns None.
See Also
--------
DataFrame.describe: Generate descriptive statistics of DataFrame
columns.
DataFrame.memory_usage: Memory usage of DataFrame columns.
Examples
--------
>>> int_values = [1, 2, 3, 4, 5]
>>> text_values = ['alpha', 'beta', 'gamma', 'delta', 'epsilon']
>>> float_values = [0.0, 0.25, 0.5, 0.75, 1.0]
>>> df = pd.DataFrame({"int_col": int_values, "text_col": text_values,
... "float_col": float_values})
>>> df
int_col text_col float_col
0 1 alpha 0.00
1 2 beta 0.25
2 3 gamma 0.50
3 4 delta 0.75
4 5 epsilon 1.00
Prints information of all columns:
>>> df.info(verbose=True)
<class 'pandas.core.frame.DataFrame'>
RangeIndex: 5 entries, 0 to 4
Data columns (total 3 columns):
# Column Non-Null Count Dtype
--- ------ -------------- -----
0 int_col 5 non-null int64
1 text_col 5 non-null object
2 float_col 5 non-null float64
dtypes: float64(1), int64(1), object(1)
memory usage: 248.0+ bytes
Prints a summary of columns count and its dtypes but not per column
information:
>>> df.info(verbose=False)
<class 'pandas.core.frame.DataFrame'>
RangeIndex: 5 entries, 0 to 4
Columns: 3 entries, int_col to float_col
dtypes: float64(1), int64(1), object(1)
memory usage: 248.0+ bytes
Pipe output of DataFrame.info to buffer instead of sys.stdout, get
buffer content and writes to a text file:
>>> import io
>>> buffer = io.StringIO()
>>> df.info(buf=buffer)
>>> s = buffer.getvalue()
>>> with open("df_info.txt", "w",
... encoding="utf-8") as f: # doctest: +SKIP
... f.write(s)
260
The `memory_usage` parameter allows deep introspection mode, specially
useful for big DataFrames and fine-tune memory optimization:
>>> random_strings_array = np.random.choice(['a', 'b', 'c'], 10 ** 6)
>>> df = pd.DataFrame({
... 'column_1': np.random.choice(['a', 'b', 'c'], 10 ** 6),
... 'column_2': np.random.choice(['a', 'b', 'c'], 10 ** 6),
... 'column_3': np.random.choice(['a', 'b', 'c'], 10 ** 6)
... })
>>> df.info()
<class 'pandas.core.frame.DataFrame'>
RangeIndex: 1000000 entries, 0 to 999999
Data columns (total 3 columns):
# Column Non-Null Count Dtype
--- ------ -------------- -----
0 column_1 1000000 non-null object
1 column_2 1000000 non-null object
2 column_3 1000000 non-null object
dtypes: object(3)
memory usage: 22.9+ MB
>>> df.info(memory_usage='deep')
<class 'pandas.core.frame.DataFrame'>
RangeIndex: 1000000 entries, 0 to 999999
Data columns (total 3 columns):
# Column Non-Null Count Dtype
--- ------ -------------- -----
0 column_1 1000000 non-null object
1 column_2 1000000 non-null object
2 column_3 1000000 non-null object
dtypes: object(3)
memory usage: 188.8 MB
"""
if buf is None: # pragma: no cover
buf = sys.stdout
lines = []
lines.append(str(type(self)))
lines.append(self.index._summary())
if len(self.columns) == 0:
lines.append(f"Empty {type(self).__name__}")
fmt.buffer_put_lines(buf, lines)
return
cols = self.columns
col_count = len(self.columns)
# hack
if max_cols is None:
max_cols = get_option("display.max_info_columns", len(self.columns) + 1)
max_rows = get_option("display.max_info_rows", len(self) + 1)
if null_counts is None:
show_counts = (col_count <= max_cols) and (len(self) < max_rows)
else:
show_counts = null_counts
exceeds_info_cols = col_count > max_cols
def _verbose_repr():
lines.append(f"Data columns (total {len(self.columns)} columns):")
id_head = " # "
column_head = "Column"
col_space = 2
max_col = max(len(pprint_thing(k)) for k in cols)
len_column = len(pprint_thing(column_head))
space = max(max_col, len_column) + col_space
max_id = len(pprint_thing(col_count))
len_id = len(pprint_thing(id_head))
space_num = max(max_id, len_id) + col_space
counts = None
header = _put_str(id_head, space_num) + _put_str(column_head, space)
if show_counts:
counts = self.count()
if len(cols) != len(counts): # pragma: no cover
raise AssertionError(
f"Columns must equal counts ({len(cols)} != {len(counts)})"
)
count_header = "Non-Null Count"
len_count = len(count_header)
non_null = " non-null"
max_count = max(len(pprint_thing(k)) for k in counts) + len(non_null)
space_count = max(len_count, max_count) + col_space
count_temp = "{count}" + non_null
else:
count_header = ""
space_count = len(count_header)
len_count = space_count
count_temp = "{count}"
dtype_header = "Dtype"
len_dtype = len(dtype_header)
max_dtypes = max(len(pprint_thing(k)) for k in self.dtypes)
space_dtype = max(len_dtype, max_dtypes)
header += _put_str(count_header, space_count) + _put_str(
dtype_header, space_dtype
)
lines.append(header)
lines.append(
_put_str("-" * len_id, space_num)
+ _put_str("-" * len_column, space)
+ _put_str("-" * len_count, space_count)
+ _put_str("-" * len_dtype, space_dtype)
)
for i, col in enumerate(self.columns):
dtype = self.dtypes.iloc[i]
col = pprint_thing(col)
line_no = _put_str(f" {i}", space_num)
count = ""
if show_counts:
count = counts.iloc[i]
lines.append(
line_no
+ _put_str(col, space)
+ _put_str(count_temp.format(count=count), space_count)
+ _put_str(dtype, space_dtype)
)
def _non_verbose_repr():
lines.append(self.columns._summary(name="Columns"))
def _sizeof_fmt(num, size_qualifier):
# returns size in human readable format
for x in ["bytes", "KB", "MB", "GB", "TB"]:
if num < 1024.0:
return f"{num:3.1f}{size_qualifier} {x}"
num /= 1024.0
return f"{num:3.1f}{size_qualifier} PB"
if verbose:
_verbose_repr()
elif verbose is False: # specifically set to False, not nesc None
_non_verbose_repr()
else:
if exceeds_info_cols:
_non_verbose_repr()
else:
_verbose_repr()
counts = self._data.get_dtype_counts()
dtypes = [f"{k[0]}({k[1]:d})" for k in sorted(counts.items())]
lines.append(f"dtypes: {', '.join(dtypes)}")
if memory_usage is None:
memory_usage = get_option("display.memory_usage")
if memory_usage:
# append memory usage of df to display
size_qualifier = ""
if memory_usage == "deep":
deep = True
else:
# size_qualifier is just a best effort; not guaranteed to catch
# all cases (e.g., it misses categorical data even with object
# categories)
deep = False
if "object" in counts or self.index._is_memory_usage_qualified():
size_qualifier = "+"
mem_usage = self.memory_usage(index=True, deep=deep).sum()
lines.append(f"memory usage: {_sizeof_fmt(mem_usage, size_qualifier)}\n")
fmt.buffer_put_lines(buf, lines)
def memory_usage(self, index=True, deep=False) -> Series:
"""
Return the memory usage of each column in bytes.
The memory usage can optionally include the contribution of
the index and elements of `object` dtype.
This value is displayed in `DataFrame.info` by default. This can be
suppressed by setting ``pandas.options.display.memory_usage`` to False.
Parameters
----------
index : bool, default True
Specifies whether to include the memory usage of the DataFrame's
index in returned Series. If ``index=True``, the memory usage of
the index is the first item in the output.
deep : bool, default False
If True, introspect the data deeply by interrogating
`object` dtypes for system-level memory consumption, and include
it in the returned values.
Returns
-------
Series
A Series whose index is the original column names and whose values
is the memory usage of each column in bytes.
See Also
--------
numpy.ndarray.nbytes : Total bytes consumed by the elements of an
ndarray.
Series.memory_usage : Bytes consumed by a Series.
Categorical : Memory-efficient array for string values with
many repeated values.
DataFrame.info : Concise summary of a DataFrame.
Examples
--------
>>> dtypes = ['int64', 'float64', 'complex128', 'object', 'bool']
>>> data = dict([(t, np.ones(shape=5000).astype(t))
... for t in dtypes])
>>> df = pd.DataFrame(data)
>>> df.head()
int64 float64 complex128 object bool
0 1 1.0 1.000000+0.000000j 1 True
1 1 1.0 1.000000+0.000000j 1 True
2 1 1.0 1.000000+0.000000j 1 True
3 1 1.0 1.000000+0.000000j 1 True
4 1 1.0 1.000000+0.000000j 1 True
>>> df.memory_usage()
Index 128
int64 40000
float64 40000
complex128 80000
object 40000
bool 5000
dtype: int64
>>> df.memory_usage(index=False)
int64 40000
float64 40000
complex128 80000
object 40000
bool 5000
dtype: int64
The memory footprint of `object` dtype columns is ignored by default:
>>> df.memory_usage(deep=True)
Index 128
int64 40000
float64 40000
complex128 80000
object 160000
bool 5000
dtype: int64
Use a Categorical for efficient storage of an object-dtype column with
many repeated values.
>>> df['object'].astype('category').memory_usage(deep=True)
5216
"""
result = Series(
[c.memory_usage(index=False, deep=deep) for col, c in self.items()],
index=self.columns,
)
if index:
result = Series(self.index.memory_usage(deep=deep), index=["Index"]).append(
result
)
return result
def transpose(self, *args, copy: bool = False) -> "DataFrame":
"""
Transpose index and columns.
Reflect the DataFrame over its main diagonal by writing rows as columns
and vice-versa. The property :attr:`.T` is an accessor to the method
:meth:`transpose`.
Parameters
----------
*args : tuple, optional
Accepted for compatibility with NumPy.
copy : bool, default False
Whether to copy the data after transposing, even for DataFrames
with a single dtype.
Note that a copy is always required for mixed dtype DataFrames,
or for DataFrames with any extension types.
Returns
-------
DataFrame
The transposed DataFrame.
See Also
--------
numpy.transpose : Permute the dimensions of a given array.
Notes
-----
Transposing a DataFrame with mixed dtypes will result in a homogeneous
DataFrame with the `object` dtype. In such a case, a copy of the data
is always made.
Examples
--------
**Square DataFrame with homogeneous dtype**
>>> d1 = {'col1': [1, 2], 'col2': [3, 4]}
>>> df1 = pd.DataFrame(data=d1)
>>> df1
col1 col2
0 1 3
1 2 4
>>> df1_transposed = df1.T # or df1.transpose()
>>> df1_transposed
0 1
col1 1 2
col2 3 4
When the dtype is homogeneous in the original DataFrame, we get a
transposed DataFrame with the same dtype:
>>> df1.dtypes
col1 int64
col2 int64
dtype: object
>>> df1_transposed.dtypes
0 int64
1 int64
dtype: object
**Non-square DataFrame with mixed dtypes**
>>> d2 = {'name': ['Alice', 'Bob'],
... 'score': [9.5, 8],
... 'employed': [False, True],
... 'kids': [0, 0]}
>>> df2 = pd.DataFrame(data=d2)
>>> df2
name score employed kids
0 Alice 9.5 False 0
1 Bob 8.0 True 0
>>> df2_transposed = df2.T # or df2.transpose()
>>> df2_transposed
0 1
name Alice Bob
score 9.5 8
employed False True
kids 0 0
When the DataFrame has mixed dtypes, we get a transposed DataFrame with
the `object` dtype:
>>> df2.dtypes
name object
score float64
employed bool
kids int64
dtype: object
>>> df2_transposed.dtypes
0 object
1 object
dtype: object
"""
nv.validate_transpose(args, dict())
# construct the args
dtypes = list(self.dtypes)
if self._is_homogeneous_type and dtypes and is_extension_array_dtype(dtypes[0]):
# We have EAs with the same dtype. We can preserve that dtype in transpose.
dtype = dtypes[0]
arr_type = dtype.construct_array_type()
values = self.values
new_values = [arr_type._from_sequence(row, dtype=dtype) for row in values]
result = self._constructor(
dict(zip(self.index, new_values)), index=self.columns
)
else:
new_values = self.values.T
if copy:
new_values = new_values.copy()
result = self._constructor(
new_values, index=self.columns, columns=self.index
)
return result.__finalize__(self)
T = property(transpose)
# ----------------------------------------------------------------------
# Indexing Methods
def _ixs(self, i: int, axis: int = 0):
"""
Parameters
----------
i : int
axis : int
Notes
-----
If slice passed, the resulting data will be a view.
"""
# irow
if axis == 0:
new_values = self._data.fast_xs(i)
# if we are a copy, mark as such
copy = isinstance(new_values, np.ndarray) and new_values.base is None
result = self._constructor_sliced(
new_values,
index=self.columns,
name=self.index[i],
dtype=new_values.dtype,
)
result._set_is_copy(self, copy=copy)
return result
# icol
else:
label = self.columns[i]
values = self._data.iget(i)
result = self._box_col_values(values, label)
# this is a cached value, mark it so
result._set_as_cached(label, self)
return result
def __getitem__(self, key):
key = lib.item_from_zerodim(key)
key = com.apply_if_callable(key, self)
if is_hashable(key):
# shortcut if the key is in columns
if self.columns.is_unique and key in self.columns:
if self.columns.nlevels > 1:
return self._getitem_multilevel(key)
return self._get_item_cache(key)
# Do we have a slicer (on rows)?
indexer = convert_to_index_sliceable(self, key)
if indexer is not None:
# either we have a slice or we have a string that can be converted
# to a slice for partial-string date indexing
return self._slice(indexer, axis=0)
# Do we have a (boolean) DataFrame?
if isinstance(key, DataFrame):
return self.where(key)
# Do we have a (boolean) 1d indexer?
if com.is_bool_indexer(key):
return self._getitem_bool_array(key)
# We are left with two options: a single key, and a collection of keys,
# We interpret tuples as collections only for non-MultiIndex
is_single_key = isinstance(key, tuple) or not is_list_like(key)
if is_single_key:
if self.columns.nlevels > 1:
return self._getitem_multilevel(key)
indexer = self.columns.get_loc(key)
if is_integer(indexer):
indexer = [indexer]
else:
if is_iterator(key):
key = list(key)
indexer = self.loc._get_listlike_indexer(key, axis=1, raise_missing=True)[1]
# take() does not accept boolean indexers
if getattr(indexer, "dtype", None) == bool:
indexer = np.where(indexer)[0]
data = self.take(indexer, axis=1)
if is_single_key:
# What does looking for a single key in a non-unique index return?
# The behavior is inconsistent. It returns a Series, except when
# - the key itself is repeated (test on data.shape, #9519), or
# - we have a MultiIndex on columns (test on self.columns, #21309)
if data.shape[1] == 1 and not isinstance(self.columns, ABCMultiIndex):
data = data[key]
return data
def _getitem_bool_array(self, key):
# also raises Exception if object array with NA values
# warning here just in case -- previously __setitem__ was
# reindexing but __getitem__ was not; it seems more reasonable to
# go with the __setitem__ behavior since that is more consistent
# with all other indexing behavior
if isinstance(key, Series) and not key.index.equals(self.index):
warnings.warn(
"Boolean Series key will be reindexed to match DataFrame index.",
UserWarning,
stacklevel=3,
)
elif len(key) != len(self.index):
raise ValueError(
f"Item wrong length {len(key)} instead of {len(self.index)}."
)
# check_bool_indexer will throw exception if Series key cannot
# be reindexed to match DataFrame rows
key = check_bool_indexer(self.index, key)
indexer = key.nonzero()[0]
return self.take(indexer, axis=0)
def _getitem_multilevel(self, key):
# self.columns is a MultiIndex
loc = self.columns.get_loc(key)
if isinstance(loc, (slice, Series, np.ndarray, Index)):
new_columns = self.columns[loc]
result_columns = maybe_droplevels(new_columns, key)
if self._is_mixed_type:
result = self.reindex(columns=new_columns)
result.columns = result_columns
else:
new_values = self.values[:, loc]
result = self._constructor(
new_values, index=self.index, columns=result_columns
)
result = result.__finalize__(self)
# If there is only one column being returned, and its name is
# either an empty string, or a tuple with an empty string as its
# first element, then treat the empty string as a placeholder
# and return the column as if the user had provided that empty
# string in the key. If the result is a Series, exclude the
# implied empty string from its name.
if len(result.columns) == 1:
top = result.columns[0]
if isinstance(top, tuple):
top = top[0]
if top == "":
result = result[""]
if isinstance(result, Series):
result = self._constructor_sliced(
result, index=self.index, name=key
)
result._set_is_copy(self)
return result
else:
return self._get_item_cache(key)
def _get_value(self, index, col, takeable: bool = False):
"""
Quickly retrieve single value at passed column and index.
Parameters
----------
index : row label
col : column label
takeable : interpret the index/col as indexers, default False
Returns
-------
scalar
"""
if takeable:
series = self._iget_item_cache(col)
return com.maybe_box_datetimelike(series._values[index])
series = self._get_item_cache(col)
engine = self.index._engine
try:
if isinstance(series._values, np.ndarray):
# i.e. not EA, we can use engine
return engine.get_value(series._values, index)
else:
loc = series.index.get_loc(index)
return series._values[loc]
except KeyError:
# GH 20629
if self.index.nlevels > 1:
# partial indexing forbidden
raise
# we cannot handle direct indexing
# use positional
col = self.columns.get_loc(col)
index = self.index.get_loc(index)
return self._get_value(index, col, takeable=True)
def __setitem__(self, key, value):
key = com.apply_if_callable(key, self)
# see if we can slice the rows
indexer = convert_to_index_sliceable(self, key)
if indexer is not None:
# either we have a slice or we have a string that can be converted
# to a slice for partial-string date indexing
return self._setitem_slice(indexer, value)
if isinstance(key, DataFrame) or getattr(key, "ndim", None) == 2:
self._setitem_frame(key, value)
elif isinstance(key, (Series, np.ndarray, list, Index)):
self._setitem_array(key, value)
else:
# set column
self._set_item(key, value)
def _setitem_slice(self, key, value):
self._check_setitem_copy()
self.loc[key] = value
def _setitem_array(self, key, value):
# also raises Exception if object array with NA values
if com.is_bool_indexer(key):
if len(key) != len(self.index):
raise ValueError(
f"Item wrong length {len(key)} instead of {len(self.index)}!"
)
key = check_bool_indexer(self.index, key)
indexer = key.nonzero()[0]
self._check_setitem_copy()
self.loc._setitem_with_indexer(indexer, value)
else:
if isinstance(value, DataFrame):
if len(value.columns) != len(key):
raise ValueError("Columns must be same length as key")
for k1, k2 in zip(key, value.columns):
self[k1] = value[k2]
else:
indexer = self.loc._get_listlike_indexer(
key, axis=1, raise_missing=False
)[1]
self._check_setitem_copy()
self.loc._setitem_with_indexer((slice(None), indexer), value)
def _setitem_frame(self, key, value):
# support boolean setting with DataFrame input, e.g.
# df[df > df2] = 0
if isinstance(key, np.ndarray):
if key.shape != self.shape:
raise ValueError("Array conditional must be same shape as self")
key = self._constructor(key, **self._construct_axes_dict())
if key.values.size and not is_bool_dtype(key.values):
raise TypeError(
"Must pass DataFrame or 2-d ndarray with boolean values only"
)
self._check_inplace_setting(value)
self._check_setitem_copy()
self._where(-key, value, inplace=True)
def _set_item(self, key, value):
"""
Add series to DataFrame in specified column.
If series is a numpy-array (not a Series/TimeSeries), it must be the
same length as the DataFrames index or an error will be thrown.
Series/TimeSeries will be conformed to the DataFrames index to
ensure homogeneity.
"""
self._ensure_valid_index(value)
value = self._sanitize_column(key, value)
NDFrame._set_item(self, key, value)
# check if we are modifying a copy
# try to set first as we want an invalid
# value exception to occur first
if len(self):
self._check_setitem_copy()
def _set_value(self, index, col, value, takeable: bool = False):
"""
Put single value at passed column and index.
Parameters
----------
index : row label
col : column label
value : scalar
takeable : interpret the index/col as indexers, default False
Returns
-------
DataFrame
If label pair is contained, will be reference to calling DataFrame,
otherwise a new object.
"""
try:
if takeable is True:
series = self._iget_item_cache(col)
return series._set_value(index, value, takeable=True)
series = self._get_item_cache(col)
engine = self.index._engine
engine.set_value(series._values, index, value)
return self
except (KeyError, TypeError):
# set using a non-recursive method & reset the cache
if takeable:
self.iloc[index, col] = value
else:
self.loc[index, col] = value
self._item_cache.pop(col, None)
return self
def _ensure_valid_index(self, value):
"""
Ensure that if we don't have an index, that we can create one from the
passed value.
"""
# GH5632, make sure that we are a Series convertible
if not len(self.index) and is_list_like(value) and len(value):
try:
value = Series(value)
except (ValueError, NotImplementedError, TypeError):
raise ValueError(
"Cannot set a frame with no defined index "
"and a value that cannot be converted to a Series"
)
self._data = self._data.reindex_axis(
value.index.copy(), axis=1, fill_value=np.nan
)
def _box_item_values(self, key, values):
items = self.columns[self.columns.get_loc(key)]
if values.ndim == 2:
return self._constructor(values.T, columns=items, index=self.index)
else:
return self._box_col_values(values, items)
def _box_col_values(self, values, items):
"""
Provide boxed values for a column.
"""
klass = self._constructor_sliced
return klass(values, index=self.index, name=items, fastpath=True)
# ----------------------------------------------------------------------
# Unsorted
def query(self, expr, inplace=False, **kwargs):
"""
Query the columns of a DataFrame with a boolean expression.
Parameters
----------
expr : str
The query string to evaluate.
You can refer to variables
in the environment by prefixing them with an '@' character like
``@a + b``.
You can refer to column names that contain spaces or operators by
surrounding them in backticks. This way you can also escape
names that start with a digit, or those that are a Python keyword.
Basically when it is not valid Python identifier. See notes down
for more details.
For example, if one of your columns is called ``a a`` and you want
to sum it with ``b``, your query should be ```a a` + b``.
.. versionadded:: 0.25.0
Backtick quoting introduced.
.. versionadded:: 1.0.0
Expanding functionality of backtick quoting for more than only spaces.
inplace : bool
Whether the query should modify the data in place or return
a modified copy.
**kwargs
See the documentation for :func:`eval` for complete details
on the keyword arguments accepted by :meth:`DataFrame.query`.
Returns
-------
DataFrame
DataFrame resulting from the provided query expression.
See Also
--------
eval : Evaluate a string describing operations on
DataFrame columns.
DataFrame.eval : Evaluate a string describing operations on
DataFrame columns.
Notes
-----
The result of the evaluation of this expression is first passed to
:attr:`DataFrame.loc` and if that fails because of a
multidimensional key (e.g., a DataFrame) then the result will be passed
to :meth:`DataFrame.__getitem__`.
This method uses the top-level :func:`eval` function to
evaluate the passed query.
The :meth:`~pandas.DataFrame.query` method uses a slightly
modified Python syntax by default. For example, the ``&`` and ``|``
(bitwise) operators have the precedence of their boolean cousins,
:keyword:`and` and :keyword:`or`. This *is* syntactically valid Python,
however the semantics are different.
You can change the semantics of the expression by passing the keyword
argument ``parser='python'``. This enforces the same semantics as
evaluation in Python space. Likewise, you can pass ``engine='python'``
to evaluate an expression using Python itself as a backend. This is not
recommended as it is inefficient compared to using ``numexpr`` as the
engine.
The :attr:`DataFrame.index` and
:attr:`DataFrame.columns` attributes of the
:class:`~pandas.DataFrame` instance are placed in the query namespace
by default, which allows you to treat both the index and columns of the
frame as a column in the frame.
The identifier ``index`` is used for the frame index; you can also
use the name of the index to identify it in a query. Please note that
Python keywords may not be used as identifiers.
For further details and examples see the ``query`` documentation in
:ref:`indexing <indexing.query>`.
*Backtick quoted variables*
Backtick quoted variables are parsed as literal Python code and
are converted internally to a Python valid identifier.
This can lead to the following problems.
During parsing a number of disallowed characters inside the backtick
quoted string are replaced by strings that are allowed as a Python identifier.
These characters include all operators in Python, the space character, the
question mark, the exclamation mark, the dollar sign, and the euro sign.
For other characters that fall outside the ASCII range (U+0001..U+007F)
and those that are not further specified in PEP 3131,
the query parser will raise an error.
This excludes whitespace different than the space character,
but also the hashtag (as it is used for comments) and the backtick
itself (backtick can also not be escaped).
In a special case, quotes that make a pair around a backtick can
confuse the parser.
For example, ```it's` > `that's``` will raise an error,
as it forms a quoted string (``'s > `that'``) with a backtick inside.
See also the Python documentation about lexical analysis
(https://docs.python.org/3/reference/lexical_analysis.html)
in combination with the source code in :mod:`pandas.core.computation.parsing`.
Examples
--------
>>> df = pd.DataFrame({'A': range(1, 6),
... 'B': range(10, 0, -2),
... 'C C': range(10, 5, -1)})
>>> df
A B C C
0 1 10 10
1 2 8 9
2 3 6 8
3 4 4 7
4 5 2 6
>>> df.query('A > B')
A B C C
4 5 2 6
The previous expression is equivalent to
>>> df[df.A > df.B]
A B C C
4 5 2 6
For columns with spaces in their name, you can use backtick quoting.
>>> df.query('B == `C C`')
A B C C
0 1 10 10
The previous expression is equivalent to
>>> df[df.B == df['C C']]
A B C C
0 1 10 10
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not isinstance(expr, str):
msg = f"expr must be a string to be evaluated, {type(expr)} given"
raise ValueError(msg)
kwargs["level"] = kwargs.pop("level", 0) + 1
kwargs["target"] = None
res = self.eval(expr, **kwargs)
try:
new_data = self.loc[res]
except ValueError:
# when res is multi-dimensional loc raises, but this is sometimes a
# valid query
new_data = self[res]
if inplace:
self._update_inplace(new_data)
else:
return new_data
def eval(self, expr, inplace=False, **kwargs):
"""
Evaluate a string describing operations on DataFrame columns.
Operates on columns only, not specific rows or elements. This allows
`eval` to run arbitrary code, which can make you vulnerable to code
injection if you pass user input to this function.
Parameters
----------
expr : str
The expression string to evaluate.
inplace : bool, default False
If the expression contains an assignment, whether to perform the
operation inplace and mutate the existing DataFrame. Otherwise,
a new DataFrame is returned.
**kwargs
See the documentation for :func:`eval` for complete details
on the keyword arguments accepted by
:meth:`~pandas.DataFrame.query`.
Returns
-------
ndarray, scalar, or pandas object
The result of the evaluation.
See Also
--------
DataFrame.query : Evaluates a boolean expression to query the columns
of a frame.
DataFrame.assign : Can evaluate an expression or function to create new
values for a column.
eval : Evaluate a Python expression as a string using various
backends.
Notes
-----
For more details see the API documentation for :func:`~eval`.
For detailed examples see :ref:`enhancing performance with eval
<enhancingperf.eval>`.
Examples
--------
>>> df = pd.DataFrame({'A': range(1, 6), 'B': range(10, 0, -2)})
>>> df
A B
0 1 10
1 2 8
2 3 6
3 4 4
4 5 2
>>> df.eval('A + B')
0 11
1 10
2 9
3 8
4 7
dtype: int64
Assignment is allowed though by default the original DataFrame is not
modified.
>>> df.eval('C = A + B')
A B C
0 1 10 11
1 2 8 10
2 3 6 9
3 4 4 8
4 5 2 7
>>> df
A B
0 1 10
1 2 8
2 3 6
3 4 4
4 5 2
Use ``inplace=True`` to modify the original DataFrame.
>>> df.eval('C = A + B', inplace=True)
>>> df
A B C
0 1 10 11
1 2 8 10
2 3 6 9
3 4 4 8
4 5 2 7
"""
from pandas.core.computation.eval import eval as _eval
inplace = validate_bool_kwarg(inplace, "inplace")
resolvers = kwargs.pop("resolvers", None)
kwargs["level"] = kwargs.pop("level", 0) + 1
if resolvers is None:
index_resolvers = self._get_index_resolvers()
column_resolvers = self._get_cleaned_column_resolvers()
resolvers = column_resolvers, index_resolvers
if "target" not in kwargs:
kwargs["target"] = self
kwargs["resolvers"] = kwargs.get("resolvers", ()) + tuple(resolvers)
return _eval(expr, inplace=inplace, **kwargs)
def select_dtypes(self, include=None, exclude=None) -> "DataFrame":
"""
Return a subset of the DataFrame's columns based on the column dtypes.
Parameters
----------
include, exclude : scalar or list-like
A selection of dtypes or strings to be included/excluded. At least
one of these parameters must be supplied.
Returns
-------
DataFrame
The subset of the frame including the dtypes in ``include`` and
excluding the dtypes in ``exclude``.
Raises
------
ValueError
* If both of ``include`` and ``exclude`` are empty
* If ``include`` and ``exclude`` have overlapping elements
* If any kind of string dtype is passed in.
Notes
-----
* To select all *numeric* types, use ``np.number`` or ``'number'``
* To select strings you must use the ``object`` dtype, but note that
this will return *all* object dtype columns
* See the `numpy dtype hierarchy
<http://docs.scipy.org/doc/numpy/reference/arrays.scalars.html>`__
* To select datetimes, use ``np.datetime64``, ``'datetime'`` or
``'datetime64'``
* To select timedeltas, use ``np.timedelta64``, ``'timedelta'`` or
``'timedelta64'``
* To select Pandas categorical dtypes, use ``'category'``
* To select Pandas datetimetz dtypes, use ``'datetimetz'`` (new in
0.20.0) or ``'datetime64[ns, tz]'``
Examples
--------
>>> df = pd.DataFrame({'a': [1, 2] * 3,
... 'b': [True, False] * 3,
... 'c': [1.0, 2.0] * 3})
>>> df
a b c
0 1 True 1.0
1 2 False 2.0
2 1 True 1.0
3 2 False 2.0
4 1 True 1.0
5 2 False 2.0
>>> df.select_dtypes(include='bool')
b
0 True
1 False
2 True
3 False
4 True
5 False
>>> df.select_dtypes(include=['float64'])
c
0 1.0
1 2.0
2 1.0
3 2.0
4 1.0
5 2.0
>>> df.select_dtypes(exclude=['int'])
b c
0 True 1.0
1 False 2.0
2 True 1.0
3 False 2.0
4 True 1.0
5 False 2.0
"""
if not is_list_like(include):
include = (include,) if include is not None else ()
if not is_list_like(exclude):
exclude = (exclude,) if exclude is not None else ()
selection = (frozenset(include), frozenset(exclude))
if not any(selection):
raise ValueError("at least one of include or exclude must be nonempty")
# convert the myriad valid dtypes object to a single representation
include = frozenset(infer_dtype_from_object(x) for x in include)
exclude = frozenset(infer_dtype_from_object(x) for x in exclude)
for dtypes in (include, exclude):
invalidate_string_dtypes(dtypes)
# can't both include AND exclude!
if not include.isdisjoint(exclude):
raise ValueError(f"include and exclude overlap on {(include & exclude)}")
# We raise when both include and exclude are empty
# Hence, we can just shrink the columns we want to keep
keep_these = np.full(self.shape[1], True)
def extract_unique_dtypes_from_dtypes_set(
dtypes_set: FrozenSet[Dtype], unique_dtypes: np.ndarray
) -> List[Dtype]:
extracted_dtypes = [
unique_dtype
for unique_dtype in unique_dtypes
if issubclass(unique_dtype.type, tuple(dtypes_set)) # type: ignore
]
return extracted_dtypes
unique_dtypes = self.dtypes.unique()
if include:
included_dtypes = extract_unique_dtypes_from_dtypes_set(
include, unique_dtypes
)
keep_these &= self.dtypes.isin(included_dtypes)
if exclude:
excluded_dtypes = extract_unique_dtypes_from_dtypes_set(
exclude, unique_dtypes
)
keep_these &= ~self.dtypes.isin(excluded_dtypes)
return self.iloc[:, keep_these.values]
def insert(self, loc, column, value, allow_duplicates=False) -> None:
"""
Insert column into DataFrame at specified location.
Raises a ValueError if `column` is already contained in the DataFrame,
unless `allow_duplicates` is set to True.
Parameters
----------
loc : int
Insertion index. Must verify 0 <= loc <= len(columns).
column : str, number, or hashable object
Label of the inserted column.
value : int, Series, or array-like
allow_duplicates : bool, optional
"""
self._ensure_valid_index(value)
value = self._sanitize_column(column, value, broadcast=False)
self._data.insert(loc, column, value, allow_duplicates=allow_duplicates)
def assign(self, **kwargs) -> "DataFrame":
r"""
Assign new columns to a DataFrame.
Returns a new object with all original columns in addition to new ones.
Existing columns that are re-assigned will be overwritten.
Parameters
----------
**kwargs : dict of {str: callable or Series}
The column names are keywords. If the values are
callable, they are computed on the DataFrame and
assigned to the new columns. The callable must not
change input DataFrame (though pandas doesn't check it).
If the values are not callable, (e.g. a Series, scalar, or array),
they are simply assigned.
Returns
-------
DataFrame
A new DataFrame with the new columns in addition to
all the existing columns.
Notes
-----
Assigning multiple columns within the same ``assign`` is possible.
Later items in '\*\*kwargs' may refer to newly created or modified
columns in 'df'; items are computed and assigned into 'df' in order.
.. versionchanged:: 0.23.0
Keyword argument order is maintained.
Examples
--------
>>> df = pd.DataFrame({'temp_c': [17.0, 25.0]},
... index=['Portland', 'Berkeley'])
>>> df
temp_c
Portland 17.0
Berkeley 25.0
Where the value is a callable, evaluated on `df`:
>>> df.assign(temp_f=lambda x: x.temp_c * 9 / 5 + 32)
temp_c temp_f
Portland 17.0 62.6
Berkeley 25.0 77.0
Alternatively, the same behavior can be achieved by directly
referencing an existing Series or sequence:
>>> df.assign(temp_f=df['temp_c'] * 9 / 5 + 32)
temp_c temp_f
Portland 17.0 62.6
Berkeley 25.0 77.0
You can create multiple columns within the same assign where one
of the columns depends on another one defined within the same assign:
>>> df.assign(temp_f=lambda x: x['temp_c'] * 9 / 5 + 32,
... temp_k=lambda x: (x['temp_f'] + 459.67) * 5 / 9)
temp_c temp_f temp_k
Portland 17.0 62.6 290.15
Berkeley 25.0 77.0 298.15
"""
data = self.copy()
for k, v in kwargs.items():
data[k] = com.apply_if_callable(v, data)
return data
def _sanitize_column(self, key, value, broadcast=True):
"""
Ensures new columns (which go into the BlockManager as new blocks) are
always copied and converted into an array.
Parameters
----------
key : object
value : scalar, Series, or array-like
broadcast : bool, default True
If ``key`` matches multiple duplicate column names in the
DataFrame, this parameter indicates whether ``value`` should be
tiled so that the returned array contains a (duplicated) column for
each occurrence of the key. If False, ``value`` will not be tiled.
Returns
-------
numpy.ndarray
"""
def reindexer(value):
# reindex if necessary
if value.index.equals(self.index) or not len(self.index):
value = value._values.copy()
else:
# GH 4107
try:
value = value.reindex(self.index)._values
except ValueError as err:
# raised in MultiIndex.from_tuples, see test_insert_error_msmgs
if not value.index.is_unique:
# duplicate axis
raise err
# other
raise TypeError(
"incompatible index of inserted column with frame index"
)
return value
if isinstance(value, Series):
value = reindexer(value)
elif isinstance(value, DataFrame):
# align right-hand-side columns if self.columns
# is multi-index and self[key] is a sub-frame
if isinstance(self.columns, ABCMultiIndex) and key in self.columns:
loc = self.columns.get_loc(key)
if isinstance(loc, (slice, Series, np.ndarray, Index)):
cols = maybe_droplevels(self.columns[loc], key)
if len(cols) and not cols.equals(value.columns):
value = value.reindex(cols, axis=1)
# now align rows
value = reindexer(value).T
elif isinstance(value, ExtensionArray):
# Explicitly copy here, instead of in sanitize_index,
# as sanitize_index won't copy an EA, even with copy=True
value = value.copy()
value = sanitize_index(value, self.index)
elif isinstance(value, Index) or is_sequence(value):
# turn me into an ndarray
value = sanitize_index(value, self.index)
if not isinstance(value, (np.ndarray, Index)):
if isinstance(value, list) and len(value) > 0:
value = maybe_convert_platform(value)
else:
value = com.asarray_tuplesafe(value)
elif value.ndim == 2:
value = value.copy().T
elif isinstance(value, Index):
value = value.copy(deep=True)
else:
value = value.copy()
# possibly infer to datetimelike
if is_object_dtype(value.dtype):
value = maybe_infer_to_datetimelike(value)
else:
# cast ignores pandas dtypes. so save the dtype first
infer_dtype, _ = infer_dtype_from_scalar(value, pandas_dtype=True)
# upcast
value = cast_scalar_to_array(len(self.index), value)
value = maybe_cast_to_datetime(value, infer_dtype)
# return internal types directly
if is_extension_array_dtype(value):
return value
# broadcast across multiple columns if necessary
if broadcast and key in self.columns and value.ndim == 1:
if not self.columns.is_unique or isinstance(self.columns, ABCMultiIndex):
existing_piece = self[key]
if isinstance(existing_piece, DataFrame):
value = np.tile(value, (len(existing_piece.columns), 1))
return np.atleast_2d(np.asarray(value))
@property
def _series(self):
return {
item: Series(self._data.iget(idx), index=self.index, name=item)
for idx, item in enumerate(self.columns)
}
def lookup(self, row_labels, col_labels) -> np.ndarray:
"""
Label-based "fancy indexing" function for DataFrame.
Given equal-length arrays of row and column labels, return an
array of the values corresponding to each (row, col) pair.
Parameters
----------
row_labels : sequence
The row labels to use for lookup.
col_labels : sequence
The column labels to use for lookup.
Returns
-------
numpy.ndarray
The found values.
"""
n = len(row_labels)
if n != len(col_labels):
raise ValueError("Row labels must have same size as column labels")
thresh = 1000
if not self._is_mixed_type or n > thresh:
values = self.values
ridx = self.index.get_indexer(row_labels)
cidx = self.columns.get_indexer(col_labels)
if (ridx == -1).any():
raise KeyError("One or more row labels was not found")
if (cidx == -1).any():
raise KeyError("One or more column labels was not found")
flat_index = ridx * len(self.columns) + cidx
result = values.flat[flat_index]
else:
result = np.empty(n, dtype="O")
for i, (r, c) in enumerate(zip(row_labels, col_labels)):
result[i] = self._get_value(r, c)
if is_object_dtype(result):
result = lib.maybe_convert_objects(result)
return result
# ----------------------------------------------------------------------
# Reindexing and alignment
def _reindex_axes(self, axes, level, limit, tolerance, method, fill_value, copy):
frame = self
columns = axes["columns"]
if columns is not None:
frame = frame._reindex_columns(
columns, method, copy, level, fill_value, limit, tolerance
)
index = axes["index"]
if index is not None:
frame = frame._reindex_index(
index, method, copy, level, fill_value, limit, tolerance
)
return frame
def _reindex_index(
self,
new_index,
method,
copy,
level,
fill_value=np.nan,
limit=None,
tolerance=None,
):
new_index, indexer = self.index.reindex(
new_index, method=method, level=level, limit=limit, tolerance=tolerance
)
return self._reindex_with_indexers(
{0: [new_index, indexer]},
copy=copy,
fill_value=fill_value,
allow_dups=False,
)
def _reindex_columns(
self,
new_columns,
method,
copy,
level,
fill_value=None,
limit=None,
tolerance=None,
):
new_columns, indexer = self.columns.reindex(
new_columns, method=method, level=level, limit=limit, tolerance=tolerance
)
return self._reindex_with_indexers(
{1: [new_columns, indexer]},
copy=copy,
fill_value=fill_value,
allow_dups=False,
)
def _reindex_multi(self, axes, copy, fill_value) -> "DataFrame":
"""
We are guaranteed non-Nones in the axes.
"""
new_index, row_indexer = self.index.reindex(axes["index"])
new_columns, col_indexer = self.columns.reindex(axes["columns"])
if row_indexer is not None and col_indexer is not None:
indexer = row_indexer, col_indexer
new_values = algorithms.take_2d_multi(
self.values, indexer, fill_value=fill_value
)
return self._constructor(new_values, index=new_index, columns=new_columns)
else:
return self._reindex_with_indexers(
{0: [new_index, row_indexer], 1: [new_columns, col_indexer]},
copy=copy,
fill_value=fill_value,
)
@Appender(_shared_docs["align"] % _shared_doc_kwargs)
def align(
self,
other,
join="outer",
axis=None,
level=None,
copy=True,
fill_value=None,
method=None,
limit=None,
fill_axis=0,
broadcast_axis=None,
) -> "DataFrame":
return super().align(
other,
join=join,
axis=axis,
level=level,
copy=copy,
fill_value=fill_value,
method=method,
limit=limit,
fill_axis=fill_axis,
broadcast_axis=broadcast_axis,
)
@Appender(
"""
>>> df = pd.DataFrame({"A": [1, 2, 3], "B": [4, 5, 6]})
Change the row labels.
>>> df.set_axis(['a', 'b', 'c'], axis='index')
A B
a 1 4
b 2 5
c 3 6
Change the column labels.
>>> df.set_axis(['I', 'II'], axis='columns')
I II
0 1 4
1 2 5
2 3 6
Now, update the labels inplace.
>>> df.set_axis(['i', 'ii'], axis='columns', inplace=True)
>>> df
i ii
0 1 4
1 2 5
2 3 6
"""
)
@Substitution(
**_shared_doc_kwargs,
extended_summary_sub=" column or",
axis_description_sub=", and 1 identifies the columns",
see_also_sub=" or columns",
)
@Appender(NDFrame.set_axis.__doc__)
def set_axis(self, labels, axis=0, inplace=False):
return super().set_axis(labels, axis=axis, inplace=inplace)
@Substitution(**_shared_doc_kwargs)
@Appender(NDFrame.reindex.__doc__)
@rewrite_axis_style_signature(
"labels",
[
("method", None),
("copy", True),
("level", None),
("fill_value", np.nan),
("limit", None),
("tolerance", None),
],
)
def reindex(self, *args, **kwargs) -> "DataFrame":
axes = validate_axis_style_args(self, args, kwargs, "labels", "reindex")
kwargs.update(axes)
# Pop these, since the values are in `kwargs` under different names
kwargs.pop("axis", None)
kwargs.pop("labels", None)
return self._ensure_type(super().reindex(**kwargs))
def drop(
self,
labels=None,
axis=0,
index=None,
columns=None,
level=None,
inplace=False,
errors="raise",
):
"""
Drop specified labels from rows or columns.
Remove rows or columns by specifying label names and corresponding
axis, or by specifying directly index or column names. When using a
multi-index, labels on different levels can be removed by specifying
the level.
Parameters
----------
labels : single label or list-like
Index or column labels to drop.
axis : {0 or 'index', 1 or 'columns'}, default 0
Whether to drop labels from the index (0 or 'index') or
columns (1 or 'columns').
index : single label or list-like
Alternative to specifying axis (``labels, axis=0``
is equivalent to ``index=labels``).
.. versionadded:: 0.21.0
columns : single label or list-like
Alternative to specifying axis (``labels, axis=1``
is equivalent to ``columns=labels``).
.. versionadded:: 0.21.0
level : int or level name, optional
For MultiIndex, level from which the labels will be removed.
inplace : bool, default False
If True, do operation inplace and return None.
errors : {'ignore', 'raise'}, default 'raise'
If 'ignore', suppress error and only existing labels are
dropped.
Returns
-------
DataFrame
DataFrame without the removed index or column labels.
Raises
------
KeyError
If any of the labels is not found in the selected axis.
See Also
--------
DataFrame.loc : Label-location based indexer for selection by label.
DataFrame.dropna : Return DataFrame with labels on given axis omitted
where (all or any) data are missing.
DataFrame.drop_duplicates : Return DataFrame with duplicate rows
removed, optionally only considering certain columns.
Series.drop : Return Series with specified index labels removed.
Examples
--------
>>> df = pd.DataFrame(np.arange(12).reshape(3, 4),
... columns=['A', 'B', 'C', 'D'])
>>> df
A B C D
0 0 1 2 3
1 4 5 6 7
2 8 9 10 11
Drop columns
>>> df.drop(['B', 'C'], axis=1)
A D
0 0 3
1 4 7
2 8 11
>>> df.drop(columns=['B', 'C'])
A D
0 0 3
1 4 7
2 8 11
Drop a row by index
>>> df.drop([0, 1])
A B C D
2 8 9 10 11
Drop columns and/or rows of MultiIndex DataFrame
>>> midx = pd.MultiIndex(levels=[['lama', 'cow', 'falcon'],
... ['speed', 'weight', 'length']],
... codes=[[0, 0, 0, 1, 1, 1, 2, 2, 2],
... [0, 1, 2, 0, 1, 2, 0, 1, 2]])
>>> df = pd.DataFrame(index=midx, columns=['big', 'small'],
... data=[[45, 30], [200, 100], [1.5, 1], [30, 20],
... [250, 150], [1.5, 0.8], [320, 250],
... [1, 0.8], [0.3, 0.2]])
>>> df
big small
lama speed 45.0 30.0
weight 200.0 100.0
length 1.5 1.0
cow speed 30.0 20.0
weight 250.0 150.0
length 1.5 0.8
falcon speed 320.0 250.0
weight 1.0 0.8
length 0.3 0.2
>>> df.drop(index='cow', columns='small')
big
lama speed 45.0
weight 200.0
length 1.5
falcon speed 320.0
weight 1.0
length 0.3
>>> df.drop(index='length', level=1)
big small
lama speed 45.0 30.0
weight 200.0 100.0
cow speed 30.0 20.0
weight 250.0 150.0
falcon speed 320.0 250.0
weight 1.0 0.8
"""
return super().drop(
labels=labels,
axis=axis,
index=index,
columns=columns,
level=level,
inplace=inplace,
errors=errors,
)
@rewrite_axis_style_signature(
"mapper",
[("copy", True), ("inplace", False), ("level", None), ("errors", "ignore")],
)
def rename(
self,
mapper: Optional[Renamer] = None,
*,
index: Optional[Renamer] = None,
columns: Optional[Renamer] = None,
axis: Optional[Axis] = None,
copy: bool = True,
inplace: bool = False,
level: Optional[Level] = None,
errors: str = "ignore",
) -> Optional["DataFrame"]:
"""
Alter axes labels.
Function / dict values must be unique (1-to-1). Labels not contained in
a dict / Series will be left as-is. Extra labels listed don't throw an
error.
See the :ref:`user guide <basics.rename>` for more.
Parameters
----------
mapper : dict-like or function
Dict-like or functions transformations to apply to
that axis' values. Use either ``mapper`` and ``axis`` to
specify the axis to target with ``mapper``, or ``index`` and
``columns``.
index : dict-like or function
Alternative to specifying axis (``mapper, axis=0``
is equivalent to ``index=mapper``).
columns : dict-like or function
Alternative to specifying axis (``mapper, axis=1``
is equivalent to ``columns=mapper``).
axis : int or str
Axis to target with ``mapper``. Can be either the axis name
('index', 'columns') or number (0, 1). The default is 'index'.
copy : bool, default True
Also copy underlying data.
inplace : bool, default False
Whether to return a new DataFrame. If True then value of copy is
ignored.
level : int or level name, default None
In case of a MultiIndex, only rename labels in the specified
level.
errors : {'ignore', 'raise'}, default 'ignore'
If 'raise', raise a `KeyError` when a dict-like `mapper`, `index`,
or `columns` contains labels that are not present in the Index
being transformed.
If 'ignore', existing keys will be renamed and extra keys will be
ignored.
Returns
-------
DataFrame
DataFrame with the renamed axis labels.
Raises
------
KeyError
If any of the labels is not found in the selected axis and
"errors='raise'".
See Also
--------
DataFrame.rename_axis : Set the name of the axis.
Examples
--------
``DataFrame.rename`` supports two calling conventions
* ``(index=index_mapper, columns=columns_mapper, ...)``
* ``(mapper, axis={'index', 'columns'}, ...)``
We *highly* recommend using keyword arguments to clarify your
intent.
Rename columns using a mapping:
>>> df = pd.DataFrame({"A": [1, 2, 3], "B": [4, 5, 6]})
>>> df.rename(columns={"A": "a", "B": "c"})
a c
0 1 4
1 2 5
2 3 6
Rename index using a mapping:
>>> df.rename(index={0: "x", 1: "y", 2: "z"})
A B
x 1 4
y 2 5
z 3 6
Cast index labels to a different type:
>>> df.index
RangeIndex(start=0, stop=3, step=1)
>>> df.rename(index=str).index
Index(['0', '1', '2'], dtype='object')
>>> df.rename(columns={"A": "a", "B": "b", "C": "c"}, errors="raise")
Traceback (most recent call last):
KeyError: ['C'] not found in axis
Using axis-style parameters
>>> df.rename(str.lower, axis='columns')
a b
0 1 4
1 2 5
2 3 6
>>> df.rename({1: 2, 2: 4}, axis='index')
A B
0 1 4
2 2 5
4 3 6
"""
return super().rename(
mapper=mapper,
index=index,
columns=columns,
axis=axis,
copy=copy,
inplace=inplace,
level=level,
errors=errors,
)
@Substitution(**_shared_doc_kwargs)
@Appender(NDFrame.fillna.__doc__)
def fillna(
self,
value=None,
method=None,
axis=None,
inplace=False,
limit=None,
downcast=None,
) -> Optional["DataFrame"]:
return super().fillna(
value=value,
method=method,
axis=axis,
inplace=inplace,
limit=limit,
downcast=downcast,
)
@Appender(_shared_docs["replace"] % _shared_doc_kwargs)
def replace(
self,
to_replace=None,
value=None,
inplace=False,
limit=None,
regex=False,
method="pad",
):
return super().replace(
to_replace=to_replace,
value=value,
inplace=inplace,
limit=limit,
regex=regex,
method=method,
)
@Appender(_shared_docs["shift"] % _shared_doc_kwargs)
def shift(self, periods=1, freq=None, axis=0, fill_value=None) -> "DataFrame":
return self._ensure_type(
super().shift(periods=periods, freq=freq, axis=axis, fill_value=fill_value)
)
def set_index(
self, keys, drop=True, append=False, inplace=False, verify_integrity=False
):
"""
Set the DataFrame index using existing columns.
Set the DataFrame index (row labels) using one or more existing
columns or arrays (of the correct length). The index can replace the
existing index or expand on it.
Parameters
----------
keys : label or array-like or list of labels/arrays
This parameter can be either a single column key, a single array of
the same length as the calling DataFrame, or a list containing an
arbitrary combination of column keys and arrays. Here, "array"
encompasses :class:`Series`, :class:`Index`, ``np.ndarray``, and
instances of :class:`~collections.abc.Iterator`.
drop : bool, default True
Delete columns to be used as the new index.
append : bool, default False
Whether to append columns to existing index.
inplace : bool, default False
Modify the DataFrame in place (do not create a new object).
verify_integrity : bool, default False
Check the new index for duplicates. Otherwise defer the check until
necessary. Setting to False will improve the performance of this
method.
Returns
-------
DataFrame
Changed row labels.
See Also
--------
DataFrame.reset_index : Opposite of set_index.
DataFrame.reindex : Change to new indices or expand indices.
DataFrame.reindex_like : Change to same indices as other DataFrame.
Examples
--------
>>> df = pd.DataFrame({'month': [1, 4, 7, 10],
... 'year': [2012, 2014, 2013, 2014],
... 'sale': [55, 40, 84, 31]})
>>> df
month year sale
0 1 2012 55
1 4 2014 40
2 7 2013 84
3 10 2014 31
Set the index to become the 'month' column:
>>> df.set_index('month')
year sale
month
1 2012 55
4 2014 40
7 2013 84
10 2014 31
Create a MultiIndex using columns 'year' and 'month':
>>> df.set_index(['year', 'month'])
sale
year month
2012 1 55
2014 4 40
2013 7 84
2014 10 31
Create a MultiIndex using an Index and a column:
>>> df.set_index([pd.Index([1, 2, 3, 4]), 'year'])
month sale
year
1 2012 1 55
2 2014 4 40
3 2013 7 84
4 2014 10 31
Create a MultiIndex using two Series:
>>> s = pd.Series([1, 2, 3, 4])
>>> df.set_index([s, s**2])
month year sale
1 1 1 2012 55
2 4 4 2014 40
3 9 7 2013 84
4 16 10 2014 31
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not isinstance(keys, list):
keys = [keys]
err_msg = (
'The parameter "keys" may be a column key, one-dimensional '
"array, or a list containing only valid column keys and "
"one-dimensional arrays."
)
missing: List[Optional[Hashable]] = []
for col in keys:
if isinstance(
col, (ABCIndexClass, ABCSeries, np.ndarray, list, abc.Iterator)
):
# arrays are fine as long as they are one-dimensional
# iterators get converted to list below
if getattr(col, "ndim", 1) != 1:
raise ValueError(err_msg)
else:
# everything else gets tried as a key; see GH 24969
try:
found = col in self.columns
except TypeError:
raise TypeError(f"{err_msg}. Received column of type {type(col)}")
else:
if not found:
missing.append(col)
if missing:
raise KeyError(f"None of {missing} are in the columns")
if inplace:
frame = self
else:
frame = self.copy()
arrays = []
names = []
if append:
names = list(self.index.names)
if isinstance(self.index, ABCMultiIndex):
for i in range(self.index.nlevels):
arrays.append(self.index._get_level_values(i))
else:
arrays.append(self.index)
to_remove: List[Optional[Hashable]] = []
for col in keys:
if isinstance(col, ABCMultiIndex):
for n in range(col.nlevels):
arrays.append(col._get_level_values(n))
names.extend(col.names)
elif isinstance(col, (ABCIndexClass, ABCSeries)):
# if Index then not MultiIndex (treated above)
arrays.append(col)
names.append(col.name)
elif isinstance(col, (list, np.ndarray)):
arrays.append(col)
names.append(None)
elif isinstance(col, abc.Iterator):
arrays.append(list(col))
names.append(None)
# from here, col can only be a column label
else:
arrays.append(frame[col]._values)
names.append(col)
if drop:
to_remove.append(col)
if len(arrays[-1]) != len(self):
# check newest element against length of calling frame, since
# ensure_index_from_sequences would not raise for append=False.
raise ValueError(
f"Length mismatch: Expected {len(self)} rows, "
f"received array of length {len(arrays[-1])}"
)
index = ensure_index_from_sequences(arrays, names)
if verify_integrity and not index.is_unique:
duplicates = index[index.duplicated()].unique()
raise ValueError(f"Index has duplicate keys: {duplicates}")
# use set to handle duplicate column names gracefully in case of drop
for c in set(to_remove):
del frame[c]
# clear up memory usage
index._cleanup()
frame.index = index
if not inplace:
return frame
def reset_index(
self,
level: Optional[Union[Hashable, Sequence[Hashable]]] = None,
drop: bool = False,
inplace: bool = False,
col_level: Hashable = 0,
col_fill: Optional[Hashable] = "",
) -> Optional["DataFrame"]:
"""
Reset the index, or a level of it.
Reset the index of the DataFrame, and use the default one instead.
If the DataFrame has a MultiIndex, this method can remove one or more
levels.
Parameters
----------
level : int, str, tuple, or list, default None
Only remove the given levels from the index. Removes all levels by
default.
drop : bool, default False
Do not try to insert index into dataframe columns. This resets
the index to the default integer index.
inplace : bool, default False
Modify the DataFrame in place (do not create a new object).
col_level : int or str, default 0
If the columns have multiple levels, determines which level the
labels are inserted into. By default it is inserted into the first
level.
col_fill : object, default ''
If the columns have multiple levels, determines how the other
levels are named. If None then the index name is repeated.
Returns
-------
DataFrame or None
DataFrame with the new index or None if ``inplace=True``.
See Also
--------
DataFrame.set_index : Opposite of reset_index.
DataFrame.reindex : Change to new indices or expand indices.
DataFrame.reindex_like : Change to same indices as other DataFrame.
Examples
--------
>>> df = pd.DataFrame([('bird', 389.0),
... ('bird', 24.0),
... ('mammal', 80.5),
... ('mammal', np.nan)],
... index=['falcon', 'parrot', 'lion', 'monkey'],
... columns=('class', 'max_speed'))
>>> df
class max_speed
falcon bird 389.0
parrot bird 24.0
lion mammal 80.5
monkey mammal NaN
When we reset the index, the old index is added as a column, and a
new sequential index is used:
>>> df.reset_index()
index class max_speed
0 falcon bird 389.0
1 parrot bird 24.0
2 lion mammal 80.5
3 monkey mammal NaN
We can use the `drop` parameter to avoid the old index being added as
a column:
>>> df.reset_index(drop=True)
class max_speed
0 bird 389.0
1 bird 24.0
2 mammal 80.5
3 mammal NaN
You can also use `reset_index` with `MultiIndex`.
>>> index = pd.MultiIndex.from_tuples([('bird', 'falcon'),
... ('bird', 'parrot'),
... ('mammal', 'lion'),
... ('mammal', 'monkey')],
... names=['class', 'name'])
>>> columns = pd.MultiIndex.from_tuples([('speed', 'max'),
... ('species', 'type')])
>>> df = pd.DataFrame([(389.0, 'fly'),
... ( 24.0, 'fly'),
... ( 80.5, 'run'),
... (np.nan, 'jump')],
... index=index,
... columns=columns)
>>> df
speed species
max type
class name
bird falcon 389.0 fly
parrot 24.0 fly
mammal lion 80.5 run
monkey NaN jump
If the index has multiple levels, we can reset a subset of them:
>>> df.reset_index(level='class')
class speed species
max type
name
falcon bird 389.0 fly
parrot bird 24.0 fly
lion mammal 80.5 run
monkey mammal NaN jump
If we are not dropping the index, by default, it is placed in the top
level. We can place it in another level:
>>> df.reset_index(level='class', col_level=1)
speed species
class max type
name
falcon bird 389.0 fly
parrot bird 24.0 fly
lion mammal 80.5 run
monkey mammal NaN jump
When the index is inserted under another level, we can specify under
which one with the parameter `col_fill`:
>>> df.reset_index(level='class', col_level=1, col_fill='species')
species speed species
class max type
name
falcon bird 389.0 fly
parrot bird 24.0 fly
lion mammal 80.5 run
monkey mammal NaN jump
If we specify a nonexistent level for `col_fill`, it is created:
>>> df.reset_index(level='class', col_level=1, col_fill='genus')
genus speed species
class max type
name
falcon bird 389.0 fly
parrot bird 24.0 fly
lion mammal 80.5 run
monkey mammal NaN jump
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if inplace:
new_obj = self
else:
new_obj = self.copy()
def _maybe_casted_values(index, labels=None):
values = index._values
if not isinstance(index, (PeriodIndex, DatetimeIndex)):
if values.dtype == np.object_:
values = lib.maybe_convert_objects(values)
# if we have the labels, extract the values with a mask
if labels is not None:
mask = labels == -1
# we can have situations where the whole mask is -1,
# meaning there is nothing found in labels, so make all nan's
if mask.all():
values = np.empty(len(mask))
values.fill(np.nan)
else:
values = values.take(labels)
# TODO(https://github.com/pandas-dev/pandas/issues/24206)
# Push this into maybe_upcast_putmask?
# We can't pass EAs there right now. Looks a bit
# complicated.
# So we unbox the ndarray_values, op, re-box.
values_type = type(values)
values_dtype = values.dtype
if issubclass(values_type, DatetimeLikeArray):
values = values._data
if mask.any():
values, _ = maybe_upcast_putmask(values, mask, np.nan)
if issubclass(values_type, DatetimeLikeArray):
values = values_type(values, dtype=values_dtype)
return values
new_index = ibase.default_index(len(new_obj))
if level is not None:
if not isinstance(level, (tuple, list)):
level = [level]
level = [self.index._get_level_number(lev) for lev in level]
if len(level) < self.index.nlevels:
new_index = self.index.droplevel(level)
if not drop:
to_insert: Iterable[Tuple[Any, Optional[Any]]]
if isinstance(self.index, ABCMultiIndex):
names = [
(n if n is not None else f"level_{i}")
for i, n in enumerate(self.index.names)
]
to_insert = zip(self.index.levels, self.index.codes)
else:
default = "index" if "index" not in self else "level_0"
names = [default] if self.index.name is None else [self.index.name]
to_insert = ((self.index, None),)
multi_col = isinstance(self.columns, ABCMultiIndex)
for i, (lev, lab) in reversed(list(enumerate(to_insert))):
if not (level is None or i in level):
continue
name = names[i]
if multi_col:
col_name = list(name) if isinstance(name, tuple) else [name]
if col_fill is None:
if len(col_name) not in (1, self.columns.nlevels):
raise ValueError(
"col_fill=None is incompatible "
f"with incomplete column name {name}"
)
col_fill = col_name[0]
lev_num = self.columns._get_level_number(col_level)
name_lst = [col_fill] * lev_num + col_name
missing = self.columns.nlevels - len(name_lst)
name_lst += [col_fill] * missing
name = tuple(name_lst)
# to ndarray and maybe infer different dtype
level_values = _maybe_casted_values(lev, lab)
new_obj.insert(0, name, level_values)
new_obj.index = new_index
if not inplace:
return new_obj
return None
# ----------------------------------------------------------------------
# Reindex-based selection methods
@Appender(_shared_docs["isna"] % _shared_doc_kwargs)
def isna(self) -> "DataFrame":
return super().isna()
@Appender(_shared_docs["isna"] % _shared_doc_kwargs)
def isnull(self) -> "DataFrame":
return super().isnull()
@Appender(_shared_docs["notna"] % _shared_doc_kwargs)
def notna(self) -> "DataFrame":
return super().notna()
@Appender(_shared_docs["notna"] % _shared_doc_kwargs)
def notnull(self) -> "DataFrame":
return super().notnull()
def dropna(self, axis=0, how="any", thresh=None, subset=None, inplace=False):
"""
Remove missing values.
See the :ref:`User Guide <missing_data>` for more on which values are
considered missing, and how to work with missing data.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
Determine if rows or columns which contain missing values are
removed.
* 0, or 'index' : Drop rows which contain missing values.
* 1, or 'columns' : Drop columns which contain missing value.
.. versionchanged:: 1.0.0
Pass tuple or list to drop on multiple axes.
Only a single axis is allowed.
how : {'any', 'all'}, default 'any'
Determine if row or column is removed from DataFrame, when we have
at least one NA or all NA.
* 'any' : If any NA values are present, drop that row or column.
* 'all' : If all values are NA, drop that row or column.
thresh : int, optional
Require that many non-NA values.
subset : array-like, optional
Labels along other axis to consider, e.g. if you are dropping rows
these would be a list of columns to include.
inplace : bool, default False
If True, do operation inplace and return None.
Returns
-------
DataFrame
DataFrame with NA entries dropped from it.
See Also
--------
DataFrame.isna: Indicate missing values.
DataFrame.notna : Indicate existing (non-missing) values.
DataFrame.fillna : Replace missing values.
Series.dropna : Drop missing values.
Index.dropna : Drop missing indices.
Examples
--------
>>> df = pd.DataFrame({"name": ['Alfred', 'Batman', 'Catwoman'],
... "toy": [np.nan, 'Batmobile', 'Bullwhip'],
... "born": [pd.NaT, pd.Timestamp("1940-04-25"),
... pd.NaT]})
>>> df
name toy born
0 Alfred NaN NaT
1 Batman Batmobile 1940-04-25
2 Catwoman Bullwhip NaT
Drop the rows where at least one element is missing.
>>> df.dropna()
name toy born
1 Batman Batmobile 1940-04-25
Drop the columns where at least one element is missing.
>>> df.dropna(axis='columns')
name
0 Alfred
1 Batman
2 Catwoman
Drop the rows where all elements are missing.
>>> df.dropna(how='all')
name toy born
0 Alfred NaN NaT
1 Batman Batmobile 1940-04-25
2 Catwoman Bullwhip NaT
Keep only the rows with at least 2 non-NA values.
>>> df.dropna(thresh=2)
name toy born
1 Batman Batmobile 1940-04-25
2 Catwoman Bullwhip NaT
Define in which columns to look for missing values.
>>> df.dropna(subset=['name', 'born'])
name toy born
1 Batman Batmobile 1940-04-25
Keep the DataFrame with valid entries in the same variable.
>>> df.dropna(inplace=True)
>>> df
name toy born
1 Batman Batmobile 1940-04-25
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if isinstance(axis, (tuple, list)):
# GH20987
raise TypeError("supplying multiple axes to axis is no longer supported.")
axis = self._get_axis_number(axis)
agg_axis = 1 - axis
agg_obj = self
if subset is not None:
ax = self._get_axis(agg_axis)
indices = ax.get_indexer_for(subset)
check = indices == -1
if check.any():
raise KeyError(list(np.compress(check, subset)))
agg_obj = self.take(indices, axis=agg_axis)
count = agg_obj.count(axis=agg_axis)
if thresh is not None:
mask = count >= thresh
elif how == "any":
mask = count == len(agg_obj._get_axis(agg_axis))
elif how == "all":
mask = count > 0
else:
if how is not None:
raise ValueError(f"invalid how option: {how}")
else:
raise TypeError("must specify how or thresh")
result = self.loc(axis=axis)[mask]
if inplace:
self._update_inplace(result)
else:
return result
def drop_duplicates(
self,
subset: Optional[Union[Hashable, Sequence[Hashable]]] = None,
keep: Union[str, bool] = "first",
inplace: bool = False,
ignore_index: bool = False,
) -> Optional["DataFrame"]:
"""
Return DataFrame with duplicate rows removed.
Considering certain columns is optional. Indexes, including time indexes
are ignored.
Parameters
----------
subset : column label or sequence of labels, optional
Only consider certain columns for identifying duplicates, by
default use all of the columns.
keep : {'first', 'last', False}, default 'first'
Determines which duplicates (if any) to keep.
- ``first`` : Drop duplicates except for the first occurrence.
- ``last`` : Drop duplicates except for the last occurrence.
- False : Drop all duplicates.
inplace : bool, default False
Whether to drop duplicates in place or to return a copy.
ignore_index : bool, default False
If True, the resulting axis will be labeled 0, 1, …, n - 1.
.. versionadded:: 1.0.0
Returns
-------
DataFrame
DataFrame with duplicates removed or None if ``inplace=True``.
"""
if self.empty:
return self.copy()
inplace = validate_bool_kwarg(inplace, "inplace")
duplicated = self.duplicated(subset, keep=keep)
if inplace:
(inds,) = (-duplicated)._ndarray_values.nonzero()
new_data = self._data.take(inds)
if ignore_index:
new_data.axes[1] = ibase.default_index(len(inds))
self._update_inplace(new_data)
else:
result = self[-duplicated]
if ignore_index:
result.index = ibase.default_index(len(result))
return result
return None
def duplicated(
self,
subset: Optional[Union[Hashable, Sequence[Hashable]]] = None,
keep: Union[str, bool] = "first",
) -> "Series":
"""
Return boolean Series denoting duplicate rows.
Considering certain columns is optional.
Parameters
----------
subset : column label or sequence of labels, optional
Only consider certain columns for identifying duplicates, by
default use all of the columns.
keep : {'first', 'last', False}, default 'first'
Determines which duplicates (if any) to mark.
- ``first`` : Mark duplicates as ``True`` except for the first occurrence.
- ``last`` : Mark duplicates as ``True`` except for the last occurrence.
- False : Mark all duplicates as ``True``.
Returns
-------
Series
"""
from pandas.core.sorting import get_group_index
from pandas._libs.hashtable import duplicated_int64, _SIZE_HINT_LIMIT
if self.empty:
return Series(dtype=bool)
def f(vals):
labels, shape = algorithms.factorize(
vals, size_hint=min(len(self), _SIZE_HINT_LIMIT)
)
return labels.astype("i8", copy=False), len(shape)
if subset is None:
subset = self.columns
elif (
not np.iterable(subset)
or isinstance(subset, str)
or isinstance(subset, tuple)
and subset in self.columns
):
subset = (subset,)
# needed for mypy since can't narrow types using np.iterable
subset = cast(Iterable, subset)
# Verify all columns in subset exist in the queried dataframe
# Otherwise, raise a KeyError, same as if you try to __getitem__ with a
# key that doesn't exist.
diff = Index(subset).difference(self.columns)
if not diff.empty:
raise KeyError(diff)
vals = (col.values for name, col in self.items() if name in subset)
labels, shape = map(list, zip(*map(f, vals)))
ids = get_group_index(labels, shape, sort=False, xnull=False)
return Series(duplicated_int64(ids, keep), index=self.index)
# ----------------------------------------------------------------------
# Sorting
@Substitution(**_shared_doc_kwargs)
@Appender(NDFrame.sort_values.__doc__)
def sort_values(
self,
by,
axis=0,
ascending=True,
inplace=False,
kind="quicksort",
na_position="last",
ignore_index=False,
):
inplace = validate_bool_kwarg(inplace, "inplace")
axis = self._get_axis_number(axis)
if not isinstance(by, list):
by = [by]
if is_sequence(ascending) and len(by) != len(ascending):
raise ValueError(
f"Length of ascending ({len(ascending)}) != length of by ({len(by)})"
)
if len(by) > 1:
from pandas.core.sorting import lexsort_indexer
keys = [self._get_label_or_level_values(x, axis=axis) for x in by]
indexer = lexsort_indexer(keys, orders=ascending, na_position=na_position)
indexer = ensure_platform_int(indexer)
else:
from pandas.core.sorting import nargsort
by = by[0]
k = self._get_label_or_level_values(by, axis=axis)
if isinstance(ascending, (tuple, list)):
ascending = ascending[0]
indexer = nargsort(
k, kind=kind, ascending=ascending, na_position=na_position
)
new_data = self._data.take(
indexer, axis=self._get_block_manager_axis(axis), verify=False
)
if ignore_index:
new_data.axes[1] = ibase.default_index(len(indexer))
if inplace:
return self._update_inplace(new_data)
else:
return self._constructor(new_data).__finalize__(self)
def sort_index(
self,
axis=0,
level=None,
ascending: bool = True,
inplace: bool = False,
kind: str = "quicksort",
na_position: str = "last",
sort_remaining: bool = True,
ignore_index: bool = False,
):
"""
Sort object by labels (along an axis).
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis along which to sort. The value 0 identifies the rows,
and 1 identifies the columns.
level : int or level name or list of ints or list of level names
If not None, sort on values in specified index level(s).
ascending : bool, default True
Sort ascending vs. descending.
inplace : bool, default False
If True, perform operation in-place.
kind : {'quicksort', 'mergesort', 'heapsort'}, default 'quicksort'
Choice of sorting algorithm. See also ndarray.np.sort for more
information. `mergesort` is the only stable algorithm. For
DataFrames, this option is only applied when sorting on a single
column or label.
na_position : {'first', 'last'}, default 'last'
Puts NaNs at the beginning if `first`; `last` puts NaNs at the end.
Not implemented for MultiIndex.
sort_remaining : bool, default True
If True and sorting by level and index is multilevel, sort by other
levels too (in order) after sorting by specified level.
ignore_index : bool, default False
If True, the resulting axis will be labeled 0, 1, …, n - 1.
.. versionadded:: 1.0.0
Returns
-------
sorted_obj : DataFrame or None
DataFrame with sorted index if inplace=False, None otherwise.
"""
# TODO: this can be combined with Series.sort_index impl as
# almost identical
inplace = validate_bool_kwarg(inplace, "inplace")
axis = self._get_axis_number(axis)
labels = self._get_axis(axis)
# make sure that the axis is lexsorted to start
# if not we need to reconstruct to get the correct indexer
labels = labels._sort_levels_monotonic()
if level is not None:
new_axis, indexer = labels.sortlevel(
level, ascending=ascending, sort_remaining=sort_remaining
)
elif isinstance(labels, ABCMultiIndex):
from pandas.core.sorting import lexsort_indexer
indexer = lexsort_indexer(
labels._get_codes_for_sorting(),
orders=ascending,
na_position=na_position,
)
else:
from pandas.core.sorting import nargsort
# Check monotonic-ness before sort an index
# GH11080
if (ascending and labels.is_monotonic_increasing) or (
not ascending and labels.is_monotonic_decreasing
):
if inplace:
return
else:
return self.copy()
indexer = nargsort(
labels, kind=kind, ascending=ascending, na_position=na_position
)
baxis = self._get_block_manager_axis(axis)
new_data = self._data.take(indexer, axis=baxis, verify=False)
# reconstruct axis if needed
new_data.axes[baxis] = new_data.axes[baxis]._sort_levels_monotonic()
if ignore_index:
new_data.axes[1] = ibase.default_index(len(indexer))
if inplace:
return self._update_inplace(new_data)
else:
return self._constructor(new_data).__finalize__(self)
def nlargest(self, n, columns, keep="first") -> "DataFrame":
"""
Return the first `n` rows ordered by `columns` in descending order.
Return the first `n` rows with the largest values in `columns`, in
descending order. The columns that are not specified are returned as
well, but not used for ordering.
This method is equivalent to
``df.sort_values(columns, ascending=False).head(n)``, but more
performant.
Parameters
----------
n : int
Number of rows to return.
columns : label or list of labels
Column label(s) to order by.
keep : {'first', 'last', 'all'}, default 'first'
Where there are duplicate values:
- `first` : prioritize the first occurrence(s)
- `last` : prioritize the last occurrence(s)
- ``all`` : do not drop any duplicates, even it means
selecting more than `n` items.
.. versionadded:: 0.24.0
Returns
-------
DataFrame
The first `n` rows ordered by the given columns in descending
order.
See Also
--------
DataFrame.nsmallest : Return the first `n` rows ordered by `columns` in
ascending order.
DataFrame.sort_values : Sort DataFrame by the values.
DataFrame.head : Return the first `n` rows without re-ordering.
Notes
-----
This function cannot be used with all column types. For example, when
specifying columns with `object` or `category` dtypes, ``TypeError`` is
raised.
Examples
--------
>>> df = pd.DataFrame({'population': [59000000, 65000000, 434000,
... 434000, 434000, 337000, 11300,
... 11300, 11300],
... 'GDP': [1937894, 2583560 , 12011, 4520, 12128,
... 17036, 182, 38, 311],
... 'alpha-2': ["IT", "FR", "MT", "MV", "BN",
... "IS", "NR", "TV", "AI"]},
... index=["Italy", "France", "Malta",
... "Maldives", "Brunei", "Iceland",
... "Nauru", "Tuvalu", "Anguilla"])
>>> df
population GDP alpha-2
Italy 59000000 1937894 IT
France 65000000 2583560 FR
Malta 434000 12011 MT
Maldives 434000 4520 MV
Brunei 434000 12128 BN
Iceland 337000 17036 IS
Nauru 11300 182 NR
Tuvalu 11300 38 TV
Anguilla 11300 311 AI
In the following example, we will use ``nlargest`` to select the three
rows having the largest values in column "population".
>>> df.nlargest(3, 'population')
population GDP alpha-2
France 65000000 2583560 FR
Italy 59000000 1937894 IT
Malta 434000 12011 MT
When using ``keep='last'``, ties are resolved in reverse order:
>>> df.nlargest(3, 'population', keep='last')
population GDP alpha-2
France 65000000 2583560 FR
Italy 59000000 1937894 IT
Brunei 434000 12128 BN
When using ``keep='all'``, all duplicate items are maintained:
>>> df.nlargest(3, 'population', keep='all')
population GDP alpha-2
France 65000000 2583560 FR
Italy 59000000 1937894 IT
Malta 434000 12011 MT
Maldives 434000 4520 MV
Brunei 434000 12128 BN
To order by the largest values in column "population" and then "GDP",
we can specify multiple columns like in the next example.
>>> df.nlargest(3, ['population', 'GDP'])
population GDP alpha-2
France 65000000 2583560 FR
Italy 59000000 1937894 IT
Brunei 434000 12128 BN
"""
return algorithms.SelectNFrame(self, n=n, keep=keep, columns=columns).nlargest()
def nsmallest(self, n, columns, keep="first") -> "DataFrame":
"""
Return the first `n` rows ordered by `columns` in ascending order.
Return the first `n` rows with the smallest values in `columns`, in
ascending order. The columns that are not specified are returned as
well, but not used for ordering.
This method is equivalent to
``df.sort_values(columns, ascending=True).head(n)``, but more
performant.
Parameters
----------
n : int
Number of items to retrieve.
columns : list or str
Column name or names to order by.
keep : {'first', 'last', 'all'}, default 'first'
Where there are duplicate values:
- ``first`` : take the first occurrence.
- ``last`` : take the last occurrence.
- ``all`` : do not drop any duplicates, even it means
selecting more than `n` items.
.. versionadded:: 0.24.0
Returns
-------
DataFrame
See Also
--------
DataFrame.nlargest : Return the first `n` rows ordered by `columns` in
descending order.
DataFrame.sort_values : Sort DataFrame by the values.
DataFrame.head : Return the first `n` rows without re-ordering.
Examples
--------
>>> df = pd.DataFrame({'population': [59000000, 65000000, 434000,
... 434000, 434000, 337000, 11300,
... 11300, 11300],
... 'GDP': [1937894, 2583560 , 12011, 4520, 12128,
... 17036, 182, 38, 311],
... 'alpha-2': ["IT", "FR", "MT", "MV", "BN",
... "IS", "NR", "TV", "AI"]},
... index=["Italy", "France", "Malta",
... "Maldives", "Brunei", "Iceland",
... "Nauru", "Tuvalu", "Anguilla"])
>>> df
population GDP alpha-2
Italy 59000000 1937894 IT
France 65000000 2583560 FR
Malta 434000 12011 MT
Maldives 434000 4520 MV
Brunei 434000 12128 BN
Iceland 337000 17036 IS
Nauru 11300 182 NR
Tuvalu 11300 38 TV
Anguilla 11300 311 AI
In the following example, we will use ``nsmallest`` to select the
three rows having the smallest values in column "a".
>>> df.nsmallest(3, 'population')
population GDP alpha-2
Nauru 11300 182 NR
Tuvalu 11300 38 TV
Anguilla 11300 311 AI
When using ``keep='last'``, ties are resolved in reverse order:
>>> df.nsmallest(3, 'population', keep='last')
population GDP alpha-2
Anguilla 11300 311 AI
Tuvalu 11300 38 TV
Nauru 11300 182 NR
When using ``keep='all'``, all duplicate items are maintained:
>>> df.nsmallest(3, 'population', keep='all')
population GDP alpha-2
Nauru 11300 182 NR
Tuvalu 11300 38 TV
Anguilla 11300 311 AI
To order by the largest values in column "a" and then "c", we can
specify multiple columns like in the next example.
>>> df.nsmallest(3, ['population', 'GDP'])
population GDP alpha-2
Tuvalu 11300 38 TV
Nauru 11300 182 NR
Anguilla 11300 311 AI
"""
return algorithms.SelectNFrame(
self, n=n, keep=keep, columns=columns
).nsmallest()
def swaplevel(self, i=-2, j=-1, axis=0) -> "DataFrame":
"""
Swap levels i and j in a MultiIndex on a particular axis.
Parameters
----------
i, j : int or str
Levels of the indices to be swapped. Can pass level name as string.
Returns
-------
DataFrame
"""
result = self.copy()
axis = self._get_axis_number(axis)
if axis == 0:
result.index = result.index.swaplevel(i, j)
else:
result.columns = result.columns.swaplevel(i, j)
return result
def reorder_levels(self, order, axis=0) -> "DataFrame":
"""
Rearrange index levels using input order. May not drop or duplicate levels.
Parameters
----------
order : list of int or list of str
List representing new level order. Reference level by number
(position) or by key (label).
axis : int
Where to reorder levels.
Returns
-------
DataFrame
"""
axis = self._get_axis_number(axis)
if not isinstance(self._get_axis(axis), ABCMultiIndex): # pragma: no cover
raise TypeError("Can only reorder levels on a hierarchical axis.")
result = self.copy()
if axis == 0:
result.index = result.index.reorder_levels(order)
else:
result.columns = result.columns.reorder_levels(order)
return result
# ----------------------------------------------------------------------
# Arithmetic / combination related
def _combine_frame(self, other, func, fill_value=None, level=None):
# at this point we have `self._indexed_same(other)`
if fill_value is None:
# since _arith_op may be called in a loop, avoid function call
# overhead if possible by doing this check once
_arith_op = func
else:
def _arith_op(left, right):
# for the mixed_type case where we iterate over columns,
# _arith_op(left, right) is equivalent to
# left._binop(right, func, fill_value=fill_value)
left, right = ops.fill_binop(left, right, fill_value)
return func(left, right)
if ops.should_series_dispatch(self, other, func):
# iterate over columns
new_data = ops.dispatch_to_series(self, other, _arith_op)
else:
with np.errstate(all="ignore"):
res_values = _arith_op(self.values, other.values)
new_data = dispatch_fill_zeros(func, self.values, other.values, res_values)
return new_data
def _combine_match_index(self, other, func):
# at this point we have `self.index.equals(other.index)`
if ops.should_series_dispatch(self, other, func):
# operate column-wise; avoid costly object-casting in `.values`
new_data = ops.dispatch_to_series(self, other, func)
else:
# fastpath --> operate directly on values
with np.errstate(all="ignore"):
new_data = func(self.values.T, other.values).T
return new_data
def _construct_result(self, result) -> "DataFrame":
"""
Wrap the result of an arithmetic, comparison, or logical operation.
Parameters
----------
result : DataFrame
Returns
-------
DataFrame
"""
out = self._constructor(result, index=self.index, copy=False)
# Pin columns instead of passing to constructor for compat with
# non-unique columns case
out.columns = self.columns
return out
def combine(
self, other: "DataFrame", func, fill_value=None, overwrite=True
) -> "DataFrame":
"""
Perform column-wise combine with another DataFrame.
Combines a DataFrame with `other` DataFrame using `func`
to element-wise combine columns. The row and column indexes of the
resulting DataFrame will be the union of the two.
Parameters
----------
other : DataFrame
The DataFrame to merge column-wise.
func : function
Function that takes two series as inputs and return a Series or a
scalar. Used to merge the two dataframes column by columns.
fill_value : scalar value, default None
The value to fill NaNs with prior to passing any column to the
merge func.
overwrite : bool, default True
If True, columns in `self` that do not exist in `other` will be
overwritten with NaNs.
Returns
-------
DataFrame
Combination of the provided DataFrames.
See Also
--------
DataFrame.combine_first : Combine two DataFrame objects and default to
non-null values in frame calling the method.
Examples
--------
Combine using a simple function that chooses the smaller column.
>>> df1 = pd.DataFrame({'A': [0, 0], 'B': [4, 4]})
>>> df2 = pd.DataFrame({'A': [1, 1], 'B': [3, 3]})
>>> take_smaller = lambda s1, s2: s1 if s1.sum() < s2.sum() else s2
>>> df1.combine(df2, take_smaller)
A B
0 0 3
1 0 3
Example using a true element-wise combine function.
>>> df1 = pd.DataFrame({'A': [5, 0], 'B': [2, 4]})
>>> df2 = pd.DataFrame({'A': [1, 1], 'B': [3, 3]})
>>> df1.combine(df2, np.minimum)
A B
0 1 2
1 0 3
Using `fill_value` fills Nones prior to passing the column to the
merge function.
>>> df1 = pd.DataFrame({'A': [0, 0], 'B': [None, 4]})
>>> df2 = pd.DataFrame({'A': [1, 1], 'B': [3, 3]})
>>> df1.combine(df2, take_smaller, fill_value=-5)
A B
0 0 -5.0
1 0 4.0
However, if the same element in both dataframes is None, that None
is preserved
>>> df1 = pd.DataFrame({'A': [0, 0], 'B': [None, 4]})
>>> df2 = pd.DataFrame({'A': [1, 1], 'B': [None, 3]})
>>> df1.combine(df2, take_smaller, fill_value=-5)
A B
0 0 -5.0
1 0 3.0
Example that demonstrates the use of `overwrite` and behavior when
the axis differ between the dataframes.
>>> df1 = pd.DataFrame({'A': [0, 0], 'B': [4, 4]})
>>> df2 = pd.DataFrame({'B': [3, 3], 'C': [-10, 1], }, index=[1, 2])
>>> df1.combine(df2, take_smaller)
A B C
0 NaN NaN NaN
1 NaN 3.0 -10.0
2 NaN 3.0 1.0
>>> df1.combine(df2, take_smaller, overwrite=False)
A B C
0 0.0 NaN NaN
1 0.0 3.0 -10.0
2 NaN 3.0 1.0
Demonstrating the preference of the passed in dataframe.
>>> df2 = pd.DataFrame({'B': [3, 3], 'C': [1, 1], }, index=[1, 2])
>>> df2.combine(df1, take_smaller)
A B C
0 0.0 NaN NaN
1 0.0 3.0 NaN
2 NaN 3.0 NaN
>>> df2.combine(df1, take_smaller, overwrite=False)
A B C
0 0.0 NaN NaN
1 0.0 3.0 1.0
2 NaN 3.0 1.0
"""
other_idxlen = len(other.index) # save for compare
this, other = self.align(other, copy=False)
new_index = this.index
if other.empty and len(new_index) == len(self.index):
return self.copy()
if self.empty and len(other) == other_idxlen:
return other.copy()
# sorts if possible
new_columns = this.columns.union(other.columns)
do_fill = fill_value is not None
result = {}
for col in new_columns:
series = this[col]
otherSeries = other[col]
this_dtype = series.dtype
other_dtype = otherSeries.dtype
this_mask = isna(series)
other_mask = isna(otherSeries)
# don't overwrite columns unnecessarily
# DO propagate if this column is not in the intersection
if not overwrite and other_mask.all():
result[col] = this[col].copy()
continue
if do_fill:
series = series.copy()
otherSeries = otherSeries.copy()
series[this_mask] = fill_value
otherSeries[other_mask] = fill_value
if col not in self.columns:
# If self DataFrame does not have col in other DataFrame,
# try to promote series, which is all NaN, as other_dtype.
new_dtype = other_dtype
try:
series = series.astype(new_dtype, copy=False)
except ValueError:
# e.g. new_dtype is integer types
pass
else:
# if we have different dtypes, possibly promote
new_dtype = find_common_type([this_dtype, other_dtype])
if not is_dtype_equal(this_dtype, new_dtype):
series = series.astype(new_dtype)
if not is_dtype_equal(other_dtype, new_dtype):
otherSeries = otherSeries.astype(new_dtype)
arr = func(series, otherSeries)
arr = maybe_downcast_to_dtype(arr, this_dtype)
result[col] = arr
# convert_objects just in case
return self._constructor(result, index=new_index, columns=new_columns)
def combine_first(self, other: "DataFrame") -> "DataFrame":
"""
Update null elements with value in the same location in `other`.
Combine two DataFrame objects by filling null values in one DataFrame
with non-null values from other DataFrame. The row and column indexes
of the resulting DataFrame will be the union of the two.
Parameters
----------
other : DataFrame
Provided DataFrame to use to fill null values.
Returns
-------
DataFrame
See Also
--------
DataFrame.combine : Perform series-wise operation on two DataFrames
using a given function.
Examples
--------
>>> df1 = pd.DataFrame({'A': [None, 0], 'B': [None, 4]})
>>> df2 = pd.DataFrame({'A': [1, 1], 'B': [3, 3]})
>>> df1.combine_first(df2)
A B
0 1.0 3.0
1 0.0 4.0
Null values still persist if the location of that null value
does not exist in `other`
>>> df1 = pd.DataFrame({'A': [None, 0], 'B': [4, None]})
>>> df2 = pd.DataFrame({'B': [3, 3], 'C': [1, 1]}, index=[1, 2])
>>> df1.combine_first(df2)
A B C
0 NaN 4.0 NaN
1 0.0 3.0 1.0
2 NaN 3.0 1.0
"""
import pandas.core.computation.expressions as expressions
def extract_values(arr):
# Does two things:
# 1. maybe gets the values from the Series / Index
# 2. convert datelike to i8
if isinstance(arr, (ABCIndexClass, ABCSeries)):
arr = arr._values
if needs_i8_conversion(arr):
if is_extension_array_dtype(arr.dtype):
arr = arr.asi8
else:
arr = arr.view("i8")
return arr
def combiner(x, y):
mask = isna(x)
if isinstance(mask, (ABCIndexClass, ABCSeries)):
mask = mask._values
x_values = extract_values(x)
y_values = extract_values(y)
# If the column y in other DataFrame is not in first DataFrame,
# just return y_values.
if y.name not in self.columns:
return y_values
return expressions.where(mask, y_values, x_values)
return self.combine(other, combiner, overwrite=False)
def update(
self, other, join="left", overwrite=True, filter_func=None, errors="ignore"
) -> None:
"""
Modify in place using non-NA values from another DataFrame.
Aligns on indices. There is no return value.
Parameters
----------
other : DataFrame, or object coercible into a DataFrame
Should have at least one matching index/column label
with the original DataFrame. If a Series is passed,
its name attribute must be set, and that will be
used as the column name to align with the original DataFrame.
join : {'left'}, default 'left'
Only left join is implemented, keeping the index and columns of the
original object.
overwrite : bool, default True
How to handle non-NA values for overlapping keys:
* True: overwrite original DataFrame's values
with values from `other`.
* False: only update values that are NA in
the original DataFrame.
filter_func : callable(1d-array) -> bool 1d-array, optional
Can choose to replace values other than NA. Return True for values
that should be updated.
errors : {'raise', 'ignore'}, default 'ignore'
If 'raise', will raise a ValueError if the DataFrame and `other`
both contain non-NA data in the same place.
.. versionchanged:: 0.24.0
Changed from `raise_conflict=False|True`
to `errors='ignore'|'raise'`.
Returns
-------
None : method directly changes calling object
Raises
------
ValueError
* When `errors='raise'` and there's overlapping non-NA data.
* When `errors` is not either `'ignore'` or `'raise'`
NotImplementedError
* If `join != 'left'`
See Also
--------
dict.update : Similar method for dictionaries.
DataFrame.merge : For column(s)-on-columns(s) operations.
Examples
--------
>>> df = pd.DataFrame({'A': [1, 2, 3],
... 'B': [400, 500, 600]})
>>> new_df = pd.DataFrame({'B': [4, 5, 6],
... 'C': [7, 8, 9]})
>>> df.update(new_df)
>>> df
A B
0 1 4
1 2 5
2 3 6
The DataFrame's length does not increase as a result of the update,
only values at matching index/column labels are updated.
>>> df = pd.DataFrame({'A': ['a', 'b', 'c'],
... 'B': ['x', 'y', 'z']})
>>> new_df = pd.DataFrame({'B': ['d', 'e', 'f', 'g', 'h', 'i']})
>>> df.update(new_df)
>>> df
A B
0 a d
1 b e
2 c f
For Series, it's name attribute must be set.
>>> df = pd.DataFrame({'A': ['a', 'b', 'c'],
... 'B': ['x', 'y', 'z']})
>>> new_column = pd.Series(['d', 'e'], name='B', index=[0, 2])
>>> df.update(new_column)
>>> df
A B
0 a d
1 b y
2 c e
>>> df = pd.DataFrame({'A': ['a', 'b', 'c'],
... 'B': ['x', 'y', 'z']})
>>> new_df = pd.DataFrame({'B': ['d', 'e']}, index=[1, 2])
>>> df.update(new_df)
>>> df
A B
0 a x
1 b d
2 c e
If `other` contains NaNs the corresponding values are not updated
in the original dataframe.
>>> df = pd.DataFrame({'A': [1, 2, 3],
... 'B': [400, 500, 600]})
>>> new_df = pd.DataFrame({'B': [4, np.nan, 6]})
>>> df.update(new_df)
>>> df
A B
0 1 4.0
1 2 500.0
2 3 6.0
"""
import pandas.core.computation.expressions as expressions
# TODO: Support other joins
if join != "left": # pragma: no cover
raise NotImplementedError("Only left join is supported")
if errors not in ["ignore", "raise"]:
raise ValueError("The parameter errors must be either 'ignore' or 'raise'")
if not isinstance(other, DataFrame):
other = DataFrame(other)
other = other.reindex_like(self)
for col in self.columns:
this = self[col]._values
that = other[col]._values
if filter_func is not None:
with np.errstate(all="ignore"):
mask = ~filter_func(this) | isna(that)
else:
if errors == "raise":
mask_this = notna(that)
mask_that = notna(this)
if any(mask_this & mask_that):
raise ValueError("Data overlaps.")
if overwrite:
mask = isna(that)
else:
mask = notna(this)
# don't overwrite columns unnecessarily
if mask.all():
continue
self[col] = expressions.where(mask, this, that)
# ----------------------------------------------------------------------
# Data reshaping
@Appender(
"""
Examples
--------
>>> df = pd.DataFrame({'Animal': ['Falcon', 'Falcon',
... 'Parrot', 'Parrot'],
... 'Max Speed': [380., 370., 24., 26.]})
>>> df
Animal Max Speed
0 Falcon 380.0
1 Falcon 370.0
2 Parrot 24.0
3 Parrot 26.0
>>> df.groupby(['Animal']).mean()
Max Speed
Animal
Falcon 375.0
Parrot 25.0
**Hierarchical Indexes**
We can groupby different levels of a hierarchical index
using the `level` parameter:
>>> arrays = [['Falcon', 'Falcon', 'Parrot', 'Parrot'],
... ['Captive', 'Wild', 'Captive', 'Wild']]
>>> index = pd.MultiIndex.from_arrays(arrays, names=('Animal', 'Type'))
>>> df = pd.DataFrame({'Max Speed': [390., 350., 30., 20.]},
... index=index)
>>> df
Max Speed
Animal Type
Falcon Captive 390.0
Wild 350.0
Parrot Captive 30.0
Wild 20.0
>>> df.groupby(level=0).mean()
Max Speed
Animal
Falcon 370.0
Parrot 25.0
>>> df.groupby(level="Type").mean()
Max Speed
Type
Captive 210.0
Wild 185.0
"""
)
@Appender(_shared_docs["groupby"] % _shared_doc_kwargs)
def groupby(
self,
by=None,
axis=0,
level=None,
as_index: bool = True,
sort: bool = True,
group_keys: bool = True,
squeeze: bool = False,
observed: bool = False,
) -> "DataFrameGroupBy":
from pandas.core.groupby.generic import DataFrameGroupBy
if level is None and by is None:
raise TypeError("You have to supply one of 'by' and 'level'")
axis = self._get_axis_number(axis)
return DataFrameGroupBy(
obj=self,
keys=by,
axis=axis,
level=level,
as_index=as_index,
sort=sort,
group_keys=group_keys,
squeeze=squeeze,
observed=observed,
)
_shared_docs[
"pivot"
] = """
Return reshaped DataFrame organized by given index / column values.
Reshape data (produce a "pivot" table) based on column values. Uses
unique values from specified `index` / `columns` to form axes of the
resulting DataFrame. This function does not support data
aggregation, multiple values will result in a MultiIndex in the
columns. See the :ref:`User Guide <reshaping>` for more on reshaping.
Parameters
----------%s
index : str or object, optional
Column to use to make new frame's index. If None, uses
existing index.
columns : str or object
Column to use to make new frame's columns.
values : str, object or a list of the previous, optional
Column(s) to use for populating new frame's values. If not
specified, all remaining columns will be used and the result will
have hierarchically indexed columns.
.. versionchanged:: 0.23.0
Also accept list of column names.
Returns
-------
DataFrame
Returns reshaped DataFrame.
Raises
------
ValueError:
When there are any `index`, `columns` combinations with multiple
values. `DataFrame.pivot_table` when you need to aggregate.
See Also
--------
DataFrame.pivot_table : Generalization of pivot that can handle
duplicate values for one index/column pair.
DataFrame.unstack : Pivot based on the index values instead of a
column.
Notes
-----
For finer-tuned control, see hierarchical indexing documentation along
with the related stack/unstack methods.
Examples
--------
>>> df = pd.DataFrame({'foo': ['one', 'one', 'one', 'two', 'two',
... 'two'],
... 'bar': ['A', 'B', 'C', 'A', 'B', 'C'],
... 'baz': [1, 2, 3, 4, 5, 6],
... 'zoo': ['x', 'y', 'z', 'q', 'w', 't']})
>>> df
foo bar baz zoo
0 one A 1 x
1 one B 2 y
2 one C 3 z
3 two A 4 q
4 two B 5 w
5 two C 6 t
>>> df.pivot(index='foo', columns='bar', values='baz')
bar A B C
foo
one 1 2 3
two 4 5 6
>>> df.pivot(index='foo', columns='bar')['baz']
bar A B C
foo
one 1 2 3
two 4 5 6
>>> df.pivot(index='foo', columns='bar', values=['baz', 'zoo'])
baz zoo
bar A B C A B C
foo
one 1 2 3 x y z
two 4 5 6 q w t
A ValueError is raised if there are any duplicates.
>>> df = pd.DataFrame({"foo": ['one', 'one', 'two', 'two'],
... "bar": ['A', 'A', 'B', 'C'],
... "baz": [1, 2, 3, 4]})
>>> df
foo bar baz
0 one A 1
1 one A 2
2 two B 3
3 two C 4
Notice that the first two rows are the same for our `index`
and `columns` arguments.
>>> df.pivot(index='foo', columns='bar', values='baz')
Traceback (most recent call last):
...
ValueError: Index contains duplicate entries, cannot reshape
"""
@Substitution("")
@Appender(_shared_docs["pivot"])
def pivot(self, index=None, columns=None, values=None) -> "DataFrame":
from pandas.core.reshape.pivot import pivot
return pivot(self, index=index, columns=columns, values=values)
_shared_docs[
"pivot_table"
] = """
Create a spreadsheet-style pivot table as a DataFrame.
The levels in the pivot table will be stored in MultiIndex objects
(hierarchical indexes) on the index and columns of the result DataFrame.
Parameters
----------%s
values : column to aggregate, optional
index : column, Grouper, array, or list of the previous
If an array is passed, it must be the same length as the data. The
list can contain any of the other types (except list).
Keys to group by on the pivot table index. If an array is passed,
it is being used as the same manner as column values.
columns : column, Grouper, array, or list of the previous
If an array is passed, it must be the same length as the data. The
list can contain any of the other types (except list).
Keys to group by on the pivot table column. If an array is passed,
it is being used as the same manner as column values.
aggfunc : function, list of functions, dict, default numpy.mean
If list of functions passed, the resulting pivot table will have
hierarchical columns whose top level are the function names
(inferred from the function objects themselves)
If dict is passed, the key is column to aggregate and value
is function or list of functions.
fill_value : scalar, default None
Value to replace missing values with.
margins : bool, default False
Add all row / columns (e.g. for subtotal / grand totals).
dropna : bool, default True
Do not include columns whose entries are all NaN.
margins_name : str, default 'All'
Name of the row / column that will contain the totals
when margins is True.
observed : bool, default False
This only applies if any of the groupers are Categoricals.
If True: only show observed values for categorical groupers.
If False: show all values for categorical groupers.
.. versionchanged:: 0.25.0
Returns
-------
DataFrame
An Excel style pivot table.
See Also
--------
DataFrame.pivot : Pivot without aggregation that can handle
non-numeric data.
Examples
--------
>>> df = pd.DataFrame({"A": ["foo", "foo", "foo", "foo", "foo",
... "bar", "bar", "bar", "bar"],
... "B": ["one", "one", "one", "two", "two",
... "one", "one", "two", "two"],
... "C": ["small", "large", "large", "small",
... "small", "large", "small", "small",
... "large"],
... "D": [1, 2, 2, 3, 3, 4, 5, 6, 7],
... "E": [2, 4, 5, 5, 6, 6, 8, 9, 9]})
>>> df
A B C D E
0 foo one small 1 2
1 foo one large 2 4
2 foo one large 2 5
3 foo two small 3 5
4 foo two small 3 6
5 bar one large 4 6
6 bar one small 5 8
7 bar two small 6 9
8 bar two large 7 9
This first example aggregates values by taking the sum.
>>> table = pd.pivot_table(df, values='D', index=['A', 'B'],
... columns=['C'], aggfunc=np.sum)
>>> table
C large small
A B
bar one 4.0 5.0
two 7.0 6.0
foo one 4.0 1.0
two NaN 6.0
We can also fill missing values using the `fill_value` parameter.
>>> table = pd.pivot_table(df, values='D', index=['A', 'B'],
... columns=['C'], aggfunc=np.sum, fill_value=0)
>>> table
C large small
A B
bar one 4 5
two 7 6
foo one 4 1
two 0 6
The next example aggregates by taking the mean across multiple columns.
>>> table = pd.pivot_table(df, values=['D', 'E'], index=['A', 'C'],
... aggfunc={'D': np.mean,
... 'E': np.mean})
>>> table
D E
A C
bar large 5.500000 7.500000
small 5.500000 8.500000
foo large 2.000000 4.500000
small 2.333333 4.333333
We can also calculate multiple types of aggregations for any given
value column.
>>> table = pd.pivot_table(df, values=['D', 'E'], index=['A', 'C'],
... aggfunc={'D': np.mean,
... 'E': [min, max, np.mean]})
>>> table
D E
mean max mean min
A C
bar large 5.500000 9.0 7.500000 6.0
small 5.500000 9.0 8.500000 8.0
foo large 2.000000 5.0 4.500000 4.0
small 2.333333 6.0 4.333333 2.0
"""
@Substitution("")
@Appender(_shared_docs["pivot_table"])
def pivot_table(
self,
values=None,
index=None,
columns=None,
aggfunc="mean",
fill_value=None,
margins=False,
dropna=True,
margins_name="All",
observed=False,
) -> "DataFrame":
from pandas.core.reshape.pivot import pivot_table
return pivot_table(
self,
values=values,
index=index,
columns=columns,
aggfunc=aggfunc,
fill_value=fill_value,
margins=margins,
dropna=dropna,
margins_name=margins_name,
observed=observed,
)
def stack(self, level=-1, dropna=True):
"""
Stack the prescribed level(s) from columns to index.
Return a reshaped DataFrame or Series having a multi-level
index with one or more new inner-most levels compared to the current
DataFrame. The new inner-most levels are created by pivoting the
columns of the current dataframe:
- if the columns have a single level, the output is a Series;
- if the columns have multiple levels, the new index
level(s) is (are) taken from the prescribed level(s) and
the output is a DataFrame.
The new index levels are sorted.
Parameters
----------
level : int, str, list, default -1
Level(s) to stack from the column axis onto the index
axis, defined as one index or label, or a list of indices
or labels.
dropna : bool, default True
Whether to drop rows in the resulting Frame/Series with
missing values. Stacking a column level onto the index
axis can create combinations of index and column values
that are missing from the original dataframe. See Examples
section.
Returns
-------
DataFrame or Series
Stacked dataframe or series.
See Also
--------
DataFrame.unstack : Unstack prescribed level(s) from index axis
onto column axis.
DataFrame.pivot : Reshape dataframe from long format to wide
format.
DataFrame.pivot_table : Create a spreadsheet-style pivot table
as a DataFrame.
Notes
-----
The function is named by analogy with a collection of books
being reorganized from being side by side on a horizontal
position (the columns of the dataframe) to being stacked
vertically on top of each other (in the index of the
dataframe).
Examples
--------
**Single level columns**
>>> df_single_level_cols = pd.DataFrame([[0, 1], [2, 3]],
... index=['cat', 'dog'],
... columns=['weight', 'height'])
Stacking a dataframe with a single level column axis returns a Series:
>>> df_single_level_cols
weight height
cat 0 1
dog 2 3
>>> df_single_level_cols.stack()
cat weight 0
height 1
dog weight 2
height 3
dtype: int64
**Multi level columns: simple case**
>>> multicol1 = pd.MultiIndex.from_tuples([('weight', 'kg'),
... ('weight', 'pounds')])
>>> df_multi_level_cols1 = pd.DataFrame([[1, 2], [2, 4]],
... index=['cat', 'dog'],
... columns=multicol1)
Stacking a dataframe with a multi-level column axis:
>>> df_multi_level_cols1
weight
kg pounds
cat 1 2
dog 2 4
>>> df_multi_level_cols1.stack()
weight
cat kg 1
pounds 2
dog kg 2
pounds 4
**Missing values**
>>> multicol2 = pd.MultiIndex.from_tuples([('weight', 'kg'),
... ('height', 'm')])
>>> df_multi_level_cols2 = pd.DataFrame([[1.0, 2.0], [3.0, 4.0]],
... index=['cat', 'dog'],
... columns=multicol2)
It is common to have missing values when stacking a dataframe
with multi-level columns, as the stacked dataframe typically
has more values than the original dataframe. Missing values
are filled with NaNs:
>>> df_multi_level_cols2
weight height
kg m
cat 1.0 2.0
dog 3.0 4.0
>>> df_multi_level_cols2.stack()
height weight
cat kg NaN 1.0
m 2.0 NaN
dog kg NaN 3.0
m 4.0 NaN
**Prescribing the level(s) to be stacked**
The first parameter controls which level or levels are stacked:
>>> df_multi_level_cols2.stack(0)
kg m
cat height NaN 2.0
weight 1.0 NaN
dog height NaN 4.0
weight 3.0 NaN
>>> df_multi_level_cols2.stack([0, 1])
cat height m 2.0
weight kg 1.0
dog height m 4.0
weight kg 3.0
dtype: float64
**Dropping missing values**
>>> df_multi_level_cols3 = pd.DataFrame([[None, 1.0], [2.0, 3.0]],
... index=['cat', 'dog'],
... columns=multicol2)
Note that rows where all values are missing are dropped by
default but this behaviour can be controlled via the dropna
keyword parameter:
>>> df_multi_level_cols3
weight height
kg m
cat NaN 1.0
dog 2.0 3.0
>>> df_multi_level_cols3.stack(dropna=False)
height weight
cat kg NaN NaN
m 1.0 NaN
dog kg NaN 2.0
m 3.0 NaN
>>> df_multi_level_cols3.stack(dropna=True)
height weight
cat m 1.0 NaN
dog kg NaN 2.0
m 3.0 NaN
"""
from pandas.core.reshape.reshape import stack, stack_multiple
if isinstance(level, (tuple, list)):
return stack_multiple(self, level, dropna=dropna)
else:
return stack(self, level, dropna=dropna)
def explode(self, column: Union[str, Tuple]) -> "DataFrame":
"""
Transform each element of a list-like to a row, replicating index values.
.. versionadded:: 0.25.0
Parameters
----------
column : str or tuple
Column to explode.
Returns
-------
DataFrame
Exploded lists to rows of the subset columns;
index will be duplicated for these rows.
Raises
------
ValueError :
if columns of the frame are not unique.
See Also
--------
DataFrame.unstack : Pivot a level of the (necessarily hierarchical)
index labels.
DataFrame.melt : Unpivot a DataFrame from wide format to long format.
Series.explode : Explode a DataFrame from list-like columns to long format.
Notes
-----
This routine will explode list-likes including lists, tuples,
Series, and np.ndarray. The result dtype of the subset rows will
be object. Scalars will be returned unchanged. Empty list-likes will
result in a np.nan for that row.
Examples
--------
>>> df = pd.DataFrame({'A': [[1, 2, 3], 'foo', [], [3, 4]], 'B': 1})
>>> df
A B
0 [1, 2, 3] 1
1 foo 1
2 [] 1
3 [3, 4] 1
>>> df.explode('A')
A B
0 1 1
0 2 1
0 3 1
1 foo 1
2 NaN 1
3 3 1
3 4 1
"""
if not (is_scalar(column) or isinstance(column, tuple)):
raise ValueError("column must be a scalar")
if not self.columns.is_unique:
raise ValueError("columns must be unique")
df = self.reset_index(drop=True)
# TODO: use overload to refine return type of reset_index
assert df is not None # needed for mypy
result = df[column].explode()
result = df.drop([column], axis=1).join(result)
result.index = self.index.take(result.index)
result = result.reindex(columns=self.columns, copy=False)
return result
def unstack(self, level=-1, fill_value=None):
"""
Pivot a level of the (necessarily hierarchical) index labels.
Returns a DataFrame having a new level of column labels whose inner-most level
consists of the pivoted index labels.
If the index is not a MultiIndex, the output will be a Series
(the analogue of stack when the columns are not a MultiIndex).
The level involved will automatically get sorted.
Parameters
----------
level : int, str, or list of these, default -1 (last level)
Level(s) of index to unstack, can pass level name.
fill_value : int, str or dict
Replace NaN with this value if the unstack produces missing values.
Returns
-------
Series or DataFrame
See Also
--------
DataFrame.pivot : Pivot a table based on column values.
DataFrame.stack : Pivot a level of the column labels (inverse operation
from `unstack`).
Examples
--------
>>> index = pd.MultiIndex.from_tuples([('one', 'a'), ('one', 'b'),
... ('two', 'a'), ('two', 'b')])
>>> s = pd.Series(np.arange(1.0, 5.0), index=index)
>>> s
one a 1.0
b 2.0
two a 3.0
b 4.0
dtype: float64
>>> s.unstack(level=-1)
a b
one 1.0 2.0
two 3.0 4.0
>>> s.unstack(level=0)
one two
a 1.0 3.0
b 2.0 4.0
>>> df = s.unstack(level=0)
>>> df.unstack()
one a 1.0
b 2.0
two a 3.0
b 4.0
dtype: float64
"""
from pandas.core.reshape.reshape import unstack
return unstack(self, level, fill_value)
_shared_docs[
"melt"
] = """
Unpivot a DataFrame from wide to long format, optionally leaving identifiers set.
This function is useful to massage a DataFrame into a format where one
or more columns are identifier variables (`id_vars`), while all other
columns, considered measured variables (`value_vars`), are "unpivoted" to
the row axis, leaving just two non-identifier columns, 'variable' and
'value'.
%(versionadded)s
Parameters
----------
id_vars : tuple, list, or ndarray, optional
Column(s) to use as identifier variables.
value_vars : tuple, list, or ndarray, optional
Column(s) to unpivot. If not specified, uses all columns that
are not set as `id_vars`.
var_name : scalar
Name to use for the 'variable' column. If None it uses
``frame.columns.name`` or 'variable'.
value_name : scalar, default 'value'
Name to use for the 'value' column.
col_level : int or str, optional
If columns are a MultiIndex then use this level to melt.
Returns
-------
DataFrame
Unpivoted DataFrame.
See Also
--------
%(other)s
pivot_table
DataFrame.pivot
Series.explode
Examples
--------
>>> df = pd.DataFrame({'A': {0: 'a', 1: 'b', 2: 'c'},
... 'B': {0: 1, 1: 3, 2: 5},
... 'C': {0: 2, 1: 4, 2: 6}})
>>> df
A B C
0 a 1 2
1 b 3 4
2 c 5 6
>>> %(caller)sid_vars=['A'], value_vars=['B'])
A variable value
0 a B 1
1 b B 3
2 c B 5
>>> %(caller)sid_vars=['A'], value_vars=['B', 'C'])
A variable value
0 a B 1
1 b B 3
2 c B 5
3 a C 2
4 b C 4
5 c C 6
The names of 'variable' and 'value' columns can be customized:
>>> %(caller)sid_vars=['A'], value_vars=['B'],
... var_name='myVarname', value_name='myValname')
A myVarname myValname
0 a B 1
1 b B 3
2 c B 5
If you have multi-index columns:
>>> df.columns = [list('ABC'), list('DEF')]
>>> df
A B C
D E F
0 a 1 2
1 b 3 4
2 c 5 6
>>> %(caller)scol_level=0, id_vars=['A'], value_vars=['B'])
A variable value
0 a B 1
1 b B 3
2 c B 5
>>> %(caller)sid_vars=[('A', 'D')], value_vars=[('B', 'E')])
(A, D) variable_0 variable_1 value
0 a B E 1
1 b B E 3
2 c B E 5
"""
@Appender(
_shared_docs["melt"]
% dict(
caller="df.melt(", versionadded=".. versionadded:: 0.20.0\n", other="melt"
)
)
def melt(
self,
id_vars=None,
value_vars=None,
var_name=None,
value_name="value",
col_level=None,
) -> "DataFrame":
from pandas.core.reshape.melt import melt
return melt(
self,
id_vars=id_vars,
value_vars=value_vars,
var_name=var_name,
value_name=value_name,
col_level=col_level,
)
# ----------------------------------------------------------------------
# Time series-related
def diff(self, periods=1, axis=0) -> "DataFrame":
"""
First discrete difference of element.
Calculates the difference of a DataFrame element compared with another
element in the DataFrame (default is the element in the same column
of the previous row).
Parameters
----------
periods : int, default 1
Periods to shift for calculating difference, accepts negative
values.
axis : {0 or 'index', 1 or 'columns'}, default 0
Take difference over rows (0) or columns (1).
Returns
-------
DataFrame
See Also
--------
Series.diff: First discrete difference for a Series.
DataFrame.pct_change: Percent change over given number of periods.
DataFrame.shift: Shift index by desired number of periods with an
optional time freq.
Notes
-----
For boolean dtypes, this uses :meth:`operator.xor` rather than
:meth:`operator.sub`.
Examples
--------
Difference with previous row
>>> df = pd.DataFrame({'a': [1, 2, 3, 4, 5, 6],
... 'b': [1, 1, 2, 3, 5, 8],
... 'c': [1, 4, 9, 16, 25, 36]})
>>> df
a b c
0 1 1 1
1 2 1 4
2 3 2 9
3 4 3 16
4 5 5 25
5 6 8 36
>>> df.diff()
a b c
0 NaN NaN NaN
1 1.0 0.0 3.0
2 1.0 1.0 5.0
3 1.0 1.0 7.0
4 1.0 2.0 9.0
5 1.0 3.0 11.0
Difference with previous column
>>> df.diff(axis=1)
a b c
0 NaN 0.0 0.0
1 NaN -1.0 3.0
2 NaN -1.0 7.0
3 NaN -1.0 13.0
4 NaN 0.0 20.0
5 NaN 2.0 28.0
Difference with 3rd previous row
>>> df.diff(periods=3)
a b c
0 NaN NaN NaN
1 NaN NaN NaN
2 NaN NaN NaN
3 3.0 2.0 15.0
4 3.0 4.0 21.0
5 3.0 6.0 27.0
Difference with following row
>>> df.diff(periods=-1)
a b c
0 -1.0 0.0 -3.0
1 -1.0 -1.0 -5.0
2 -1.0 -1.0 -7.0
3 -1.0 -2.0 -9.0
4 -1.0 -3.0 -11.0
5 NaN NaN NaN
"""
bm_axis = self._get_block_manager_axis(axis)
new_data = self._data.diff(n=periods, axis=bm_axis)
return self._constructor(new_data)
# ----------------------------------------------------------------------
# Function application
def _gotitem(
self,
key: Union[str, List[str]],
ndim: int,
subset: Optional[Union[Series, ABCDataFrame]] = None,
) -> Union[Series, ABCDataFrame]:
"""
Sub-classes to define. Return a sliced object.
Parameters
----------
key : string / list of selections
ndim : 1,2
requested ndim of result
subset : object, default None
subset to act on
"""
if subset is None:
subset = self
elif subset.ndim == 1: # is Series
return subset
# TODO: _shallow_copy(subset)?
return subset[key]
_agg_summary_and_see_also_doc = dedent(
"""
The aggregation operations are always performed over an axis, either the
index (default) or the column axis. This behavior is different from
`numpy` aggregation functions (`mean`, `median`, `prod`, `sum`, `std`,
`var`), where the default is to compute the aggregation of the flattened
array, e.g., ``numpy.mean(arr_2d)`` as opposed to
``numpy.mean(arr_2d, axis=0)``.
`agg` is an alias for `aggregate`. Use the alias.
See Also
--------
DataFrame.apply : Perform any type of operations.
DataFrame.transform : Perform transformation type operations.
core.groupby.GroupBy : Perform operations over groups.
core.resample.Resampler : Perform operations over resampled bins.
core.window.Rolling : Perform operations over rolling window.
core.window.Expanding : Perform operations over expanding window.
core.window.EWM : Perform operation over exponential weighted
window.
"""
)
_agg_examples_doc = dedent(
"""
Examples
--------
>>> df = pd.DataFrame([[1, 2, 3],
... [4, 5, 6],
... [7, 8, 9],
... [np.nan, np.nan, np.nan]],
... columns=['A', 'B', 'C'])
Aggregate these functions over the rows.
>>> df.agg(['sum', 'min'])
A B C
sum 12.0 15.0 18.0
min 1.0 2.0 3.0
Different aggregations per column.
>>> df.agg({'A' : ['sum', 'min'], 'B' : ['min', 'max']})
A B
max NaN 8.0
min 1.0 2.0
sum 12.0 NaN
Aggregate over the columns.
>>> df.agg("mean", axis="columns")
0 2.0
1 5.0
2 8.0
3 NaN
dtype: float64
"""
)
@Substitution(
see_also=_agg_summary_and_see_also_doc,
examples=_agg_examples_doc,
versionadded="\n.. versionadded:: 0.20.0\n",
**_shared_doc_kwargs,
)
@Appender(_shared_docs["aggregate"])
def aggregate(self, func, axis=0, *args, **kwargs):
axis = self._get_axis_number(axis)
result = None
try:
result, how = self._aggregate(func, axis=axis, *args, **kwargs)
except TypeError:
pass
if result is None:
return self.apply(func, axis=axis, args=args, **kwargs)
return result
def _aggregate(self, arg, axis=0, *args, **kwargs):
if axis == 1:
# NDFrame.aggregate returns a tuple, and we need to transpose
# only result
result, how = self.T._aggregate(arg, *args, **kwargs)
result = result.T if result is not None else result
return result, how
return super()._aggregate(arg, *args, **kwargs)
agg = aggregate
@Appender(_shared_docs["transform"] % _shared_doc_kwargs)
def transform(self, func, axis=0, *args, **kwargs) -> "DataFrame":
axis = self._get_axis_number(axis)
if axis == 1:
return self.T.transform(func, *args, **kwargs).T
return super().transform(func, *args, **kwargs)
def apply(self, func, axis=0, raw=False, result_type=None, args=(), **kwds):
"""
Apply a function along an axis of the DataFrame.
Objects passed to the function are Series objects whose index is
either the DataFrame's index (``axis=0``) or the DataFrame's columns
(``axis=1``). By default (``result_type=None``), the final return type
is inferred from the return type of the applied function. Otherwise,
it depends on the `result_type` argument.
Parameters
----------
func : function
Function to apply to each column or row.
axis : {0 or 'index', 1 or 'columns'}, default 0
Axis along which the function is applied:
* 0 or 'index': apply function to each column.
* 1 or 'columns': apply function to each row.
raw : bool, default False
Determines if row or column is passed as a Series or ndarray object:
* ``False`` : passes each row or column as a Series to the
function.
* ``True`` : the passed function will receive ndarray objects
instead.
If you are just applying a NumPy reduction function this will
achieve much better performance.
result_type : {'expand', 'reduce', 'broadcast', None}, default None
These only act when ``axis=1`` (columns):
* 'expand' : list-like results will be turned into columns.
* 'reduce' : returns a Series if possible rather than expanding
list-like results. This is the opposite of 'expand'.
* 'broadcast' : results will be broadcast to the original shape
of the DataFrame, the original index and columns will be
retained.
The default behaviour (None) depends on the return value of the
applied function: list-like results will be returned as a Series
of those. However if the apply function returns a Series these
are expanded to columns.
.. versionadded:: 0.23.0
args : tuple
Positional arguments to pass to `func` in addition to the
array/series.
**kwds
Additional keyword arguments to pass as keywords arguments to
`func`.
Returns
-------
Series or DataFrame
Result of applying ``func`` along the given axis of the
DataFrame.
See Also
--------
DataFrame.applymap: For elementwise operations.
DataFrame.aggregate: Only perform aggregating type operations.
DataFrame.transform: Only perform transforming type operations.
Examples
--------
>>> df = pd.DataFrame([[4, 9]] * 3, columns=['A', 'B'])
>>> df
A B
0 4 9
1 4 9
2 4 9
Using a numpy universal function (in this case the same as
``np.sqrt(df)``):
>>> df.apply(np.sqrt)
A B
0 2.0 3.0
1 2.0 3.0
2 2.0 3.0
Using a reducing function on either axis
>>> df.apply(np.sum, axis=0)
A 12
B 27
dtype: int64
>>> df.apply(np.sum, axis=1)
0 13
1 13
2 13
dtype: int64
Returning a list-like will result in a Series
>>> df.apply(lambda x: [1, 2], axis=1)
0 [1, 2]
1 [1, 2]
2 [1, 2]
dtype: object
Passing result_type='expand' will expand list-like results
to columns of a Dataframe
>>> df.apply(lambda x: [1, 2], axis=1, result_type='expand')
0 1
0 1 2
1 1 2
2 1 2
Returning a Series inside the function is similar to passing
``result_type='expand'``. The resulting column names
will be the Series index.
>>> df.apply(lambda x: pd.Series([1, 2], index=['foo', 'bar']), axis=1)
foo bar
0 1 2
1 1 2
2 1 2
Passing ``result_type='broadcast'`` will ensure the same shape
result, whether list-like or scalar is returned by the function,
and broadcast it along the axis. The resulting column names will
be the originals.
>>> df.apply(lambda x: [1, 2], axis=1, result_type='broadcast')
A B
0 1 2
1 1 2
2 1 2
"""
from pandas.core.apply import frame_apply
op = frame_apply(
self,
func=func,
axis=axis,
raw=raw,
result_type=result_type,
args=args,
kwds=kwds,
)
return op.get_result()
def applymap(self, func) -> "DataFrame":
"""
Apply a function to a Dataframe elementwise.
This method applies a function that accepts and returns a scalar
to every element of a DataFrame.
Parameters
----------
func : callable
Python function, returns a single value from a single value.
Returns
-------
DataFrame
Transformed DataFrame.
See Also
--------
DataFrame.apply : Apply a function along input axis of DataFrame.
Notes
-----
In the current implementation applymap calls `func` twice on the
first column/row to decide whether it can take a fast or slow
code path. This can lead to unexpected behavior if `func` has
side-effects, as they will take effect twice for the first
column/row.
Examples
--------
>>> df = pd.DataFrame([[1, 2.12], [3.356, 4.567]])
>>> df
0 1
0 1.000 2.120
1 3.356 4.567
>>> df.applymap(lambda x: len(str(x)))
0 1
0 3 4
1 5 5
Note that a vectorized version of `func` often exists, which will
be much faster. You could square each number elementwise.
>>> df.applymap(lambda x: x**2)
0 1
0 1.000000 4.494400
1 11.262736 20.857489
But it's better to avoid applymap in that case.
>>> df ** 2
0 1
0 1.000000 4.494400
1 11.262736 20.857489
"""
# if we have a dtype == 'M8[ns]', provide boxed values
def infer(x):
if x.empty:
return lib.map_infer(x, func)
return lib.map_infer(x.astype(object).values, func)
return self.apply(infer)
# ----------------------------------------------------------------------
# Merging / joining methods
def append(
self, other, ignore_index=False, verify_integrity=False, sort=False
) -> "DataFrame":
"""
Append rows of `other` to the end of caller, returning a new object.
Columns in `other` that are not in the caller are added as new columns.
Parameters
----------
other : DataFrame or Series/dict-like object, or list of these
The data to append.
ignore_index : bool, default False
If True, do not use the index labels.
verify_integrity : bool, default False
If True, raise ValueError on creating index with duplicates.
sort : bool, default False
Sort columns if the columns of `self` and `other` are not aligned.
.. versionadded:: 0.23.0
.. versionchanged:: 1.0.0
Changed to not sort by default.
Returns
-------
DataFrame
See Also
--------
concat : General function to concatenate DataFrame or Series objects.
Notes
-----
If a list of dict/series is passed and the keys are all contained in
the DataFrame's index, the order of the columns in the resulting
DataFrame will be unchanged.
Iteratively appending rows to a DataFrame can be more computationally
intensive than a single concatenate. A better solution is to append
those rows to a list and then concatenate the list with the original
DataFrame all at once.
Examples
--------
>>> df = pd.DataFrame([[1, 2], [3, 4]], columns=list('AB'))
>>> df
A B
0 1 2
1 3 4
>>> df2 = pd.DataFrame([[5, 6], [7, 8]], columns=list('AB'))
>>> df.append(df2)
A B
0 1 2
1 3 4
0 5 6
1 7 8
With `ignore_index` set to True:
>>> df.append(df2, ignore_index=True)
A B
0 1 2
1 3 4
2 5 6
3 7 8
The following, while not recommended methods for generating DataFrames,
show two ways to generate a DataFrame from multiple data sources.
Less efficient:
>>> df = pd.DataFrame(columns=['A'])
>>> for i in range(5):
... df = df.append({'A': i}, ignore_index=True)
>>> df
A
0 0
1 1
2 2
3 3
4 4
More efficient:
>>> pd.concat([pd.DataFrame([i], columns=['A']) for i in range(5)],
... ignore_index=True)
A
0 0
1 1
2 2
3 3
4 4
"""
if isinstance(other, (Series, dict)):
if isinstance(other, dict):
if not ignore_index:
raise TypeError("Can only append a dict if ignore_index=True")
other = Series(other)
if other.name is None and not ignore_index:
raise TypeError(
"Can only append a Series if ignore_index=True "
"or if the Series has a name"
)
index = Index([other.name], name=self.index.name)
idx_diff = other.index.difference(self.columns)
try:
combined_columns = self.columns.append(idx_diff)
except TypeError:
combined_columns = self.columns.astype(object).append(idx_diff)
other = (
other.reindex(combined_columns, copy=False)
.to_frame()
.T.infer_objects()
.rename_axis(index.names, copy=False)
)
if not self.columns.equals(combined_columns):
self = self.reindex(columns=combined_columns)
elif isinstance(other, list):
if not other:
pass
elif not isinstance(other[0], DataFrame):
other = DataFrame(other)
if (self.columns.get_indexer(other.columns) >= 0).all():
other = other.reindex(columns=self.columns)
from pandas.core.reshape.concat import concat
if isinstance(other, (list, tuple)):
to_concat = [self, *other]
else:
to_concat = [self, other]
return concat(
to_concat,
ignore_index=ignore_index,
verify_integrity=verify_integrity,
sort=sort,
)
def join(
self, other, on=None, how="left", lsuffix="", rsuffix="", sort=False
) -> "DataFrame":
"""
Join columns of another DataFrame.
Join columns with `other` DataFrame either on index or on a key
column. Efficiently join multiple DataFrame objects by index at once by
passing a list.
Parameters
----------
other : DataFrame, Series, or list of DataFrame
Index should be similar to one of the columns in this one. If a
Series is passed, its name attribute must be set, and that will be
used as the column name in the resulting joined DataFrame.
on : str, list of str, or array-like, optional
Column or index level name(s) in the caller to join on the index
in `other`, otherwise joins index-on-index. If multiple
values given, the `other` DataFrame must have a MultiIndex. Can
pass an array as the join key if it is not already contained in
the calling DataFrame. Like an Excel VLOOKUP operation.
how : {'left', 'right', 'outer', 'inner'}, default 'left'
How to handle the operation of the two objects.
* left: use calling frame's index (or column if on is specified)
* right: use `other`'s index.
* outer: form union of calling frame's index (or column if on is
specified) with `other`'s index, and sort it.
lexicographically.
* inner: form intersection of calling frame's index (or column if
on is specified) with `other`'s index, preserving the order
of the calling's one.
lsuffix : str, default ''
Suffix to use from left frame's overlapping columns.
rsuffix : str, default ''
Suffix to use from right frame's overlapping columns.
sort : bool, default False
Order result DataFrame lexicographically by the join key. If False,
the order of the join key depends on the join type (how keyword).
Returns
-------
DataFrame
A dataframe containing columns from both the caller and `other`.
See Also
--------
DataFrame.merge : For column(s)-on-columns(s) operations.
Notes
-----
Parameters `on`, `lsuffix`, and `rsuffix` are not supported when
passing a list of `DataFrame` objects.
Support for specifying index levels as the `on` parameter was added
in version 0.23.0.
Examples
--------
>>> df = pd.DataFrame({'key': ['K0', 'K1', 'K2', 'K3', 'K4', 'K5'],
... 'A': ['A0', 'A1', 'A2', 'A3', 'A4', 'A5']})
>>> df
key A
0 K0 A0
1 K1 A1
2 K2 A2
3 K3 A3
4 K4 A4
5 K5 A5
>>> other = pd.DataFrame({'key': ['K0', 'K1', 'K2'],
... 'B': ['B0', 'B1', 'B2']})
>>> other
key B
0 K0 B0
1 K1 B1
2 K2 B2
Join DataFrames using their indexes.
>>> df.join(other, lsuffix='_caller', rsuffix='_other')
key_caller A key_other B
0 K0 A0 K0 B0
1 K1 A1 K1 B1
2 K2 A2 K2 B2
3 K3 A3 NaN NaN
4 K4 A4 NaN NaN
5 K5 A5 NaN NaN
If we want to join using the key columns, we need to set key to be
the index in both `df` and `other`. The joined DataFrame will have
key as its index.
>>> df.set_index('key').join(other.set_index('key'))
A B
key
K0 A0 B0
K1 A1 B1
K2 A2 B2
K3 A3 NaN
K4 A4 NaN
K5 A5 NaN
Another option to join using the key columns is to use the `on`
parameter. DataFrame.join always uses `other`'s index but we can use
any column in `df`. This method preserves the original DataFrame's
index in the result.
>>> df.join(other.set_index('key'), on='key')
key A B
0 K0 A0 B0
1 K1 A1 B1
2 K2 A2 B2
3 K3 A3 NaN
4 K4 A4 NaN
5 K5 A5 NaN
"""
return self._join_compat(
other, on=on, how=how, lsuffix=lsuffix, rsuffix=rsuffix, sort=sort
)
def _join_compat(
self, other, on=None, how="left", lsuffix="", rsuffix="", sort=False
):
from pandas.core.reshape.merge import merge
from pandas.core.reshape.concat import concat
if isinstance(other, Series):
if other.name is None:
raise ValueError("Other Series must have a name")
other = DataFrame({other.name: other})
if isinstance(other, DataFrame):
return merge(
self,
other,
left_on=on,
how=how,
left_index=on is None,
right_index=True,
suffixes=(lsuffix, rsuffix),
sort=sort,
)
else:
if on is not None:
raise ValueError(
"Joining multiple DataFrames only supported for joining on index"
)
frames = [self] + list(other)
can_concat = all(df.index.is_unique for df in frames)
# join indexes only using concat
if can_concat:
if how == "left":
res = concat(
frames, axis=1, join="outer", verify_integrity=True, sort=sort
)
return res.reindex(self.index, copy=False)
else:
return concat(
frames, axis=1, join=how, verify_integrity=True, sort=sort
)
joined = frames[0]
for frame in frames[1:]:
joined = merge(
joined, frame, how=how, left_index=True, right_index=True
)
return joined
@Substitution("")
@Appender(_merge_doc, indents=2)
def merge(
self,
right,
how="inner",
on=None,
left_on=None,
right_on=None,
left_index=False,
right_index=False,
sort=False,
suffixes=("_x", "_y"),
copy=True,
indicator=False,
validate=None,
) -> "DataFrame":
from pandas.core.reshape.merge import merge
return merge(
self,
right,
how=how,
on=on,
left_on=left_on,
right_on=right_on,
left_index=left_index,
right_index=right_index,
sort=sort,
suffixes=suffixes,
copy=copy,
indicator=indicator,
validate=validate,
)
def round(self, decimals=0, *args, **kwargs) -> "DataFrame":
"""
Round a DataFrame to a variable number of decimal places.
Parameters
----------
decimals : int, dict, Series
Number of decimal places to round each column to. If an int is
given, round each column to the same number of places.
Otherwise dict and Series round to variable numbers of places.
Column names should be in the keys if `decimals` is a
dict-like, or in the index if `decimals` is a Series. Any
columns not included in `decimals` will be left as is. Elements
of `decimals` which are not columns of the input will be
ignored.
*args
Additional keywords have no effect but might be accepted for
compatibility with numpy.
**kwargs
Additional keywords have no effect but might be accepted for
compatibility with numpy.
Returns
-------
DataFrame
A DataFrame with the affected columns rounded to the specified
number of decimal places.
See Also
--------
numpy.around : Round a numpy array to the given number of decimals.
Series.round : Round a Series to the given number of decimals.
Examples
--------
>>> df = pd.DataFrame([(.21, .32), (.01, .67), (.66, .03), (.21, .18)],
... columns=['dogs', 'cats'])
>>> df
dogs cats
0 0.21 0.32
1 0.01 0.67
2 0.66 0.03
3 0.21 0.18
By providing an integer each column is rounded to the same number
of decimal places
>>> df.round(1)
dogs cats
0 0.2 0.3
1 0.0 0.7
2 0.7 0.0
3 0.2 0.2
With a dict, the number of places for specific columns can be
specified with the column names as key and the number of decimal
places as value
>>> df.round({'dogs': 1, 'cats': 0})
dogs cats
0 0.2 0.0
1 0.0 1.0
2 0.7 0.0
3 0.2 0.0
Using a Series, the number of places for specific columns can be
specified with the column names as index and the number of
decimal places as value
>>> decimals = pd.Series([0, 1], index=['cats', 'dogs'])
>>> df.round(decimals)
dogs cats
0 0.2 0.0
1 0.0 1.0
2 0.7 0.0
3 0.2 0.0
"""
from pandas.core.reshape.concat import concat
def _dict_round(df, decimals):
for col, vals in df.items():
try:
yield _series_round(vals, decimals[col])
except KeyError:
yield vals
def _series_round(s, decimals):
if is_integer_dtype(s) or is_float_dtype(s):
return s.round(decimals)
return s
nv.validate_round(args, kwargs)
if isinstance(decimals, (dict, Series)):
if isinstance(decimals, Series):
if not decimals.index.is_unique:
raise ValueError("Index of decimals must be unique")
new_cols = list(_dict_round(self, decimals))
elif is_integer(decimals):
# Dispatch to Series.round
new_cols = [_series_round(v, decimals) for _, v in self.items()]
else:
raise TypeError("decimals must be an integer, a dict-like or a Series")
if len(new_cols) > 0:
return self._constructor(
concat(new_cols, axis=1), index=self.index, columns=self.columns
)
else:
return self
# ----------------------------------------------------------------------
# Statistical methods, etc.
def corr(self, method="pearson", min_periods=1) -> "DataFrame":
"""
Compute pairwise correlation of columns, excluding NA/null values.
Parameters
----------
method : {'pearson', 'kendall', 'spearman'} or callable
Method of correlation:
* pearson : standard correlation coefficient
* kendall : Kendall Tau correlation coefficient
* spearman : Spearman rank correlation
* callable: callable with input two 1d ndarrays
and returning a float. Note that the returned matrix from corr
will have 1 along the diagonals and will be symmetric
regardless of the callable's behavior.
.. versionadded:: 0.24.0
min_periods : int, optional
Minimum number of observations required per pair of columns
to have a valid result. Currently only available for Pearson
and Spearman correlation.
Returns
-------
DataFrame
Correlation matrix.
See Also
--------
DataFrame.corrwith
Series.corr
Examples
--------
>>> def histogram_intersection(a, b):
... v = np.minimum(a, b).sum().round(decimals=1)
... return v
>>> df = pd.DataFrame([(.2, .3), (.0, .6), (.6, .0), (.2, .1)],
... columns=['dogs', 'cats'])
>>> df.corr(method=histogram_intersection)
dogs cats
dogs 1.0 0.3
cats 0.3 1.0
"""
numeric_df = self._get_numeric_data()
cols = numeric_df.columns
idx = cols.copy()
mat = numeric_df.values
if method == "pearson":
correl = libalgos.nancorr(ensure_float64(mat), minp=min_periods)
elif method == "spearman":
correl = libalgos.nancorr_spearman(ensure_float64(mat), minp=min_periods)
elif method == "kendall" or callable(method):
if min_periods is None:
min_periods = 1
mat = ensure_float64(mat).T
corrf = nanops.get_corr_func(method)
K = len(cols)
correl = np.empty((K, K), dtype=float)
mask = np.isfinite(mat)
for i, ac in enumerate(mat):
for j, bc in enumerate(mat):
if i > j:
continue
valid = mask[i] & mask[j]
if valid.sum() < min_periods:
c = np.nan
elif i == j:
c = 1.0
elif not valid.all():
c = corrf(ac[valid], bc[valid])
else:
c = corrf(ac, bc)
correl[i, j] = c
correl[j, i] = c
else:
raise ValueError(
"method must be either 'pearson', "
"'spearman', 'kendall', or a callable, "
f"'{method}' was supplied"
)
return self._constructor(correl, index=idx, columns=cols)
def cov(self, min_periods=None) -> "DataFrame":
"""
Compute pairwise covariance of columns, excluding NA/null values.
Compute the pairwise covariance among the series of a DataFrame.
The returned data frame is the `covariance matrix
<https://en.wikipedia.org/wiki/Covariance_matrix>`__ of the columns
of the DataFrame.
Both NA and null values are automatically excluded from the
calculation. (See the note below about bias from missing values.)
A threshold can be set for the minimum number of
observations for each value created. Comparisons with observations
below this threshold will be returned as ``NaN``.
This method is generally used for the analysis of time series data to
understand the relationship between different measures
across time.
Parameters
----------
min_periods : int, optional
Minimum number of observations required per pair of columns
to have a valid result.
Returns
-------
DataFrame
The covariance matrix of the series of the DataFrame.
See Also
--------
Series.cov : Compute covariance with another Series.
core.window.EWM.cov: Exponential weighted sample covariance.
core.window.Expanding.cov : Expanding sample covariance.
core.window.Rolling.cov : Rolling sample covariance.
Notes
-----
Returns the covariance matrix of the DataFrame's time series.
The covariance is normalized by N-1.
For DataFrames that have Series that are missing data (assuming that
data is `missing at random
<https://en.wikipedia.org/wiki/Missing_data#Missing_at_random>`__)
the returned covariance matrix will be an unbiased estimate
of the variance and covariance between the member Series.
However, for many applications this estimate may not be acceptable
because the estimate covariance matrix is not guaranteed to be positive
semi-definite. This could lead to estimate correlations having
absolute values which are greater than one, and/or a non-invertible
covariance matrix. See `Estimation of covariance matrices
<http://en.wikipedia.org/w/index.php?title=Estimation_of_covariance_
matrices>`__ for more details.
Examples
--------
>>> df = pd.DataFrame([(1, 2), (0, 3), (2, 0), (1, 1)],
... columns=['dogs', 'cats'])
>>> df.cov()
dogs cats
dogs 0.666667 -1.000000
cats -1.000000 1.666667
>>> np.random.seed(42)
>>> df = pd.DataFrame(np.random.randn(1000, 5),
... columns=['a', 'b', 'c', 'd', 'e'])
>>> df.cov()
a b c d e
a 0.998438 -0.020161 0.059277 -0.008943 0.014144
b -0.020161 1.059352 -0.008543 -0.024738 0.009826
c 0.059277 -0.008543 1.010670 -0.001486 -0.000271
d -0.008943 -0.024738 -0.001486 0.921297 -0.013692
e 0.014144 0.009826 -0.000271 -0.013692 0.977795
**Minimum number of periods**
This method also supports an optional ``min_periods`` keyword
that specifies the required minimum number of non-NA observations for
each column pair in order to have a valid result:
>>> np.random.seed(42)
>>> df = pd.DataFrame(np.random.randn(20, 3),
... columns=['a', 'b', 'c'])
>>> df.loc[df.index[:5], 'a'] = np.nan
>>> df.loc[df.index[5:10], 'b'] = np.nan
>>> df.cov(min_periods=12)
a b c
a 0.316741 NaN -0.150812
b NaN 1.248003 0.191417
c -0.150812 0.191417 0.895202
"""
numeric_df = self._get_numeric_data()
cols = numeric_df.columns
idx = cols.copy()
mat = numeric_df.values
if notna(mat).all():
if min_periods is not None and min_periods > len(mat):
baseCov = np.empty((mat.shape[1], mat.shape[1]))
baseCov.fill(np.nan)
else:
baseCov = np.cov(mat.T)
baseCov = baseCov.reshape((len(cols), len(cols)))
else:
baseCov = libalgos.nancorr(ensure_float64(mat), cov=True, minp=min_periods)
return self._constructor(baseCov, index=idx, columns=cols)
def corrwith(self, other, axis=0, drop=False, method="pearson") -> Series:
"""
Compute pairwise correlation.
Pairwise correlation is computed between rows or columns of
DataFrame with rows or columns of Series or DataFrame. DataFrames
are first aligned along both axes before computing the
correlations.
Parameters
----------
other : DataFrame, Series
Object with which to compute correlations.
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to use. 0 or 'index' to compute column-wise, 1 or 'columns' for
row-wise.
drop : bool, default False
Drop missing indices from result.
method : {'pearson', 'kendall', 'spearman'} or callable
Method of correlation:
* pearson : standard correlation coefficient
* kendall : Kendall Tau correlation coefficient
* spearman : Spearman rank correlation
* callable: callable with input two 1d ndarrays
and returning a float.
.. versionadded:: 0.24.0
Returns
-------
Series
Pairwise correlations.
See Also
--------
DataFrame.corr
"""
axis = self._get_axis_number(axis)
this = self._get_numeric_data()
if isinstance(other, Series):
return this.apply(lambda x: other.corr(x, method=method), axis=axis)
other = other._get_numeric_data()
left, right = this.align(other, join="inner", copy=False)
if axis == 1:
left = left.T
right = right.T
if method == "pearson":
# mask missing values
left = left + right * 0
right = right + left * 0
# demeaned data
ldem = left - left.mean()
rdem = right - right.mean()
num = (ldem * rdem).sum()
dom = (left.count() - 1) * left.std() * right.std()
correl = num / dom
elif method in ["kendall", "spearman"] or callable(method):
def c(x):
return nanops.nancorr(x[0], x[1], method=method)
correl = Series(
map(c, zip(left.values.T, right.values.T)), index=left.columns
)
else:
raise ValueError(
f"Invalid method {method} was passed, "
"valid methods are: 'pearson', 'kendall', "
"'spearman', or callable"
)
if not drop:
# Find non-matching labels along the given axis
# and append missing correlations (GH 22375)
raxis = 1 if axis == 0 else 0
result_index = this._get_axis(raxis).union(other._get_axis(raxis))
idx_diff = result_index.difference(correl.index)
if len(idx_diff) > 0:
correl = correl.append(Series([np.nan] * len(idx_diff), index=idx_diff))
return correl
# ----------------------------------------------------------------------
# ndarray-like stats methods
def count(self, axis=0, level=None, numeric_only=False):
"""
Count non-NA cells for each column or row.
The values `None`, `NaN`, `NaT`, and optionally `numpy.inf` (depending
on `pandas.options.mode.use_inf_as_na`) are considered NA.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
If 0 or 'index' counts are generated for each column.
If 1 or 'columns' counts are generated for each **row**.
level : int or str, optional
If the axis is a `MultiIndex` (hierarchical), count along a
particular `level`, collapsing into a `DataFrame`.
A `str` specifies the level name.
numeric_only : bool, default False
Include only `float`, `int` or `boolean` data.
Returns
-------
Series or DataFrame
For each column/row the number of non-NA/null entries.
If `level` is specified returns a `DataFrame`.
See Also
--------
Series.count: Number of non-NA elements in a Series.
DataFrame.shape: Number of DataFrame rows and columns (including NA
elements).
DataFrame.isna: Boolean same-sized DataFrame showing places of NA
elements.
Examples
--------
Constructing DataFrame from a dictionary:
>>> df = pd.DataFrame({"Person":
... ["John", "Myla", "Lewis", "John", "Myla"],
... "Age": [24., np.nan, 21., 33, 26],
... "Single": [False, True, True, True, False]})
>>> df
Person Age Single
0 John 24.0 False
1 Myla NaN True
2 Lewis 21.0 True
3 John 33.0 True
4 Myla 26.0 False
Notice the uncounted NA values:
>>> df.count()
Person 5
Age 4
Single 5
dtype: int64
Counts for each **row**:
>>> df.count(axis='columns')
0 3
1 2
2 3
3 3
4 3
dtype: int64
Counts for one level of a `MultiIndex`:
>>> df.set_index(["Person", "Single"]).count(level="Person")
Age
Person
John 2
Lewis 1
Myla 1
"""
axis = self._get_axis_number(axis)
if level is not None:
return self._count_level(level, axis=axis, numeric_only=numeric_only)
if numeric_only:
frame = self._get_numeric_data()
else:
frame = self
# GH #423
if len(frame._get_axis(axis)) == 0:
result = Series(0, index=frame._get_agg_axis(axis))
else:
if frame._is_mixed_type or frame._data.any_extension_types:
# the or any_extension_types is really only hit for single-
# column frames with an extension array
result = notna(frame).sum(axis=axis)
else:
# GH13407
series_counts = notna(frame).sum(axis=axis)
counts = series_counts.values
result = Series(counts, index=frame._get_agg_axis(axis))
return result.astype("int64")
def _count_level(self, level, axis=0, numeric_only=False):
if numeric_only:
frame = self._get_numeric_data()
else:
frame = self
count_axis = frame._get_axis(axis)
agg_axis = frame._get_agg_axis(axis)
if not isinstance(count_axis, ABCMultiIndex):
raise TypeError(
f"Can only count levels on hierarchical {self._get_axis_name(axis)}."
)
if frame._is_mixed_type:
# Since we have mixed types, calling notna(frame.values) might
# upcast everything to object
mask = notna(frame).values
else:
# But use the speedup when we have homogeneous dtypes
mask = notna(frame.values)
if axis == 1:
# We're transposing the mask rather than frame to avoid potential
# upcasts to object, which induces a ~20x slowdown
mask = mask.T
if isinstance(level, str):
level = count_axis._get_level_number(level)
level_name = count_axis._names[level]
level_index = count_axis.levels[level]._shallow_copy(name=level_name)
level_codes = ensure_int64(count_axis.codes[level])
counts = lib.count_level_2d(mask, level_codes, len(level_index), axis=0)
result = DataFrame(counts, index=level_index, columns=agg_axis)
if axis == 1:
# Undo our earlier transpose
return result.T
else:
return result
def _reduce(
self, op, name, axis=0, skipna=True, numeric_only=None, filter_type=None, **kwds
):
if axis is None and filter_type == "bool":
labels = None
constructor = None
else:
# TODO: Make other agg func handle axis=None properly
axis = self._get_axis_number(axis)
labels = self._get_agg_axis(axis)
constructor = self._constructor
def f(x):
return op(x, axis=axis, skipna=skipna, **kwds)
def _get_data(axis_matters):
if filter_type is None or filter_type == "numeric":
data = self._get_numeric_data()
elif filter_type == "bool":
if axis_matters:
# GH#25101, GH#24434
data = self._get_bool_data() if axis == 0 else self
else:
data = self._get_bool_data()
else: # pragma: no cover
msg = (
f"Generating numeric_only data with filter_type {filter_type} "
"not supported."
)
raise NotImplementedError(msg)
return data
if numeric_only is not None and axis in [0, 1]:
df = self
if numeric_only is True:
df = _get_data(axis_matters=True)
if axis == 1:
df = df.T
axis = 0
out_dtype = "bool" if filter_type == "bool" else None
# After possibly _get_data and transposing, we are now in the
# simple case where we can use BlockManager._reduce
res = df._data.reduce(op, axis=1, skipna=skipna, **kwds)
assert isinstance(res, dict)
if len(res):
assert len(res) == max(list(res.keys())) + 1, res.keys()
out = df._constructor_sliced(res, index=range(len(res)), dtype=out_dtype)
out.index = df.columns
return out
if numeric_only is None:
values = self.values
try:
result = f(values)
if filter_type == "bool" and is_object_dtype(values) and axis is None:
# work around https://github.com/numpy/numpy/issues/10489
# TODO: combine with hasattr(result, 'dtype') further down
# hard since we don't have `values` down there.
result = np.bool_(result)
except TypeError:
# e.g. in nanops trying to convert strs to float
# try by-column first
if filter_type is None and axis == 0:
# this can end up with a non-reduction
# but not always. if the types are mixed
# with datelike then need to make sure a series
# we only end up here if we have not specified
# numeric_only and yet we have tried a
# column-by-column reduction, where we have mixed type.
# So let's just do what we can
from pandas.core.apply import frame_apply
opa = frame_apply(
self, func=f, result_type="expand", ignore_failures=True
)
result = opa.get_result()
if result.ndim == self.ndim:
result = result.iloc[0]
return result
# TODO: why doesnt axis matter here?
data = _get_data(axis_matters=False)
with np.errstate(all="ignore"):
result = f(data.values)
labels = data._get_agg_axis(axis)
else:
if numeric_only:
data = _get_data(axis_matters=True)
values = data.values
labels = data._get_agg_axis(axis)
else:
values = self.values
result = f(values)
if hasattr(result, "dtype") and is_object_dtype(result.dtype):
try:
if filter_type is None or filter_type == "numeric":
result = result.astype(np.float64)
elif filter_type == "bool" and notna(result).all():
result = result.astype(np.bool_)
except (ValueError, TypeError):
# try to coerce to the original dtypes item by item if we can
if axis == 0:
result = coerce_to_dtypes(result, self.dtypes)
if constructor is not None:
result = self._constructor_sliced(result, index=labels)
return result
def nunique(self, axis=0, dropna=True) -> Series:
"""
Count distinct observations over requested axis.
Return Series with number of distinct observations. Can ignore NaN
values.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to use. 0 or 'index' for row-wise, 1 or 'columns' for
column-wise.
dropna : bool, default True
Don't include NaN in the counts.
Returns
-------
Series
See Also
--------
Series.nunique: Method nunique for Series.
DataFrame.count: Count non-NA cells for each column or row.
Examples
--------
>>> df = pd.DataFrame({'A': [1, 2, 3], 'B': [1, 1, 1]})
>>> df.nunique()
A 3
B 1
dtype: int64
>>> df.nunique(axis=1)
0 1
1 2
2 2
dtype: int64
"""
return self.apply(Series.nunique, axis=axis, dropna=dropna)
def idxmin(self, axis=0, skipna=True) -> Series:
"""
Return index of first occurrence of minimum over requested axis.
NA/null values are excluded.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to use. 0 or 'index' for row-wise, 1 or 'columns' for column-wise.
skipna : bool, default True
Exclude NA/null values. If an entire row/column is NA, the result
will be NA.
Returns
-------
Series
Indexes of minima along the specified axis.
Raises
------
ValueError
* If the row/column is empty
See Also
--------
Series.idxmin
Notes
-----
This method is the DataFrame version of ``ndarray.argmin``.
"""
axis = self._get_axis_number(axis)
indices = nanops.nanargmin(self.values, axis=axis, skipna=skipna)
index = self._get_axis(axis)
result = [index[i] if i >= 0 else np.nan for i in indices]
return Series(result, index=self._get_agg_axis(axis))
def idxmax(self, axis=0, skipna=True) -> Series:
"""
Return index of first occurrence of maximum over requested axis.
NA/null values are excluded.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to use. 0 or 'index' for row-wise, 1 or 'columns' for column-wise.
skipna : bool, default True
Exclude NA/null values. If an entire row/column is NA, the result
will be NA.
Returns
-------
Series
Indexes of maxima along the specified axis.
Raises
------
ValueError
* If the row/column is empty
See Also
--------
Series.idxmax
Notes
-----
This method is the DataFrame version of ``ndarray.argmax``.
"""
axis = self._get_axis_number(axis)
indices = nanops.nanargmax(self.values, axis=axis, skipna=skipna)
index = self._get_axis(axis)
result = [index[i] if i >= 0 else np.nan for i in indices]
return Series(result, index=self._get_agg_axis(axis))
def _get_agg_axis(self, axis_num):
"""
Let's be explicit about this.
"""
if axis_num == 0:
return self.columns
elif axis_num == 1:
return self.index
else:
raise ValueError(f"Axis must be 0 or 1 (got {repr(axis_num)})")
def mode(self, axis=0, numeric_only=False, dropna=True) -> "DataFrame":
"""
Get the mode(s) of each element along the selected axis.
The mode of a set of values is the value that appears most often.
It can be multiple values.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to iterate over while searching for the mode:
* 0 or 'index' : get mode of each column
* 1 or 'columns' : get mode of each row.
numeric_only : bool, default False
If True, only apply to numeric columns.
dropna : bool, default True
Don't consider counts of NaN/NaT.
.. versionadded:: 0.24.0
Returns
-------
DataFrame
The modes of each column or row.
See Also
--------
Series.mode : Return the highest frequency value in a Series.
Series.value_counts : Return the counts of values in a Series.
Examples
--------
>>> df = pd.DataFrame([('bird', 2, 2),
... ('mammal', 4, np.nan),
... ('arthropod', 8, 0),
... ('bird', 2, np.nan)],
... index=('falcon', 'horse', 'spider', 'ostrich'),
... columns=('species', 'legs', 'wings'))
>>> df
species legs wings
falcon bird 2 2.0
horse mammal 4 NaN
spider arthropod 8 0.0
ostrich bird 2 NaN
By default, missing values are not considered, and the mode of wings
are both 0 and 2. The second row of species and legs contains ``NaN``,
because they have only one mode, but the DataFrame has two rows.
>>> df.mode()
species legs wings
0 bird 2.0 0.0
1 NaN NaN 2.0
Setting ``dropna=False`` ``NaN`` values are considered and they can be
the mode (like for wings).
>>> df.mode(dropna=False)
species legs wings
0 bird 2 NaN
Setting ``numeric_only=True``, only the mode of numeric columns is
computed, and columns of other types are ignored.
>>> df.mode(numeric_only=True)
legs wings
0 2.0 0.0
1 NaN 2.0
To compute the mode over columns and not rows, use the axis parameter:
>>> df.mode(axis='columns', numeric_only=True)
0 1
falcon 2.0 NaN
horse 4.0 NaN
spider 0.0 8.0
ostrich 2.0 NaN
"""
data = self if not numeric_only else self._get_numeric_data()
def f(s):
return s.mode(dropna=dropna)
return data.apply(f, axis=axis)
def quantile(self, q=0.5, axis=0, numeric_only=True, interpolation="linear"):
"""
Return values at the given quantile over requested axis.
Parameters
----------
q : float or array-like, default 0.5 (50% quantile)
Value between 0 <= q <= 1, the quantile(s) to compute.
axis : {0, 1, 'index', 'columns'} (default 0)
Equals 0 or 'index' for row-wise, 1 or 'columns' for column-wise.
numeric_only : bool, default True
If False, the quantile of datetime and timedelta data will be
computed as well.
interpolation : {'linear', 'lower', 'higher', 'midpoint', 'nearest'}
This optional parameter specifies the interpolation method to use,
when the desired quantile lies between two data points `i` and `j`:
* linear: `i + (j - i) * fraction`, where `fraction` is the
fractional part of the index surrounded by `i` and `j`.
* lower: `i`.
* higher: `j`.
* nearest: `i` or `j` whichever is nearest.
* midpoint: (`i` + `j`) / 2.
Returns
-------
Series or DataFrame
If ``q`` is an array, a DataFrame will be returned where the
index is ``q``, the columns are the columns of self, and the
values are the quantiles.
If ``q`` is a float, a Series will be returned where the
index is the columns of self and the values are the quantiles.
See Also
--------
core.window.Rolling.quantile: Rolling quantile.
numpy.percentile: Numpy function to compute the percentile.
Examples
--------
>>> df = pd.DataFrame(np.array([[1, 1], [2, 10], [3, 100], [4, 100]]),
... columns=['a', 'b'])
>>> df.quantile(.1)
a 1.3
b 3.7
Name: 0.1, dtype: float64
>>> df.quantile([.1, .5])
a b
0.1 1.3 3.7
0.5 2.5 55.0
Specifying `numeric_only=False` will also compute the quantile of
datetime and timedelta data.
>>> df = pd.DataFrame({'A': [1, 2],
... 'B': [pd.Timestamp('2010'),
... pd.Timestamp('2011')],
... 'C': [pd.Timedelta('1 days'),
... pd.Timedelta('2 days')]})
>>> df.quantile(0.5, numeric_only=False)
A 1.5
B 2010-07-02 12:00:00
C 1 days 12:00:00
Name: 0.5, dtype: object
"""
validate_percentile(q)
data = self._get_numeric_data() if numeric_only else self
axis = self._get_axis_number(axis)
is_transposed = axis == 1
if is_transposed:
data = data.T
if len(data.columns) == 0:
# GH#23925 _get_numeric_data may have dropped all columns
cols = Index([], name=self.columns.name)
if is_list_like(q):
return self._constructor([], index=q, columns=cols)
return self._constructor_sliced([], index=cols, name=q, dtype=np.float64)
result = data._data.quantile(
qs=q, axis=1, interpolation=interpolation, transposed=is_transposed
)
if result.ndim == 2:
result = self._constructor(result)
else:
result = self._constructor_sliced(result, name=q)
if is_transposed:
result = result.T
return result
def to_timestamp(self, freq=None, how="start", axis=0, copy=True) -> "DataFrame":
"""
Cast to DatetimeIndex of timestamps, at *beginning* of period.
Parameters
----------
freq : str, default frequency of PeriodIndex
Desired frequency.
how : {'s', 'e', 'start', 'end'}
Convention for converting period to timestamp; start of period
vs. end.
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to convert (the index by default).
copy : bool, default True
If False then underlying input data is not copied.
Returns
-------
DataFrame with DatetimeIndex
"""
new_data = self._data
if copy:
new_data = new_data.copy()
axis = self._get_axis_number(axis)
if axis == 0:
new_data.set_axis(1, self.index.to_timestamp(freq=freq, how=how))
elif axis == 1:
new_data.set_axis(0, self.columns.to_timestamp(freq=freq, how=how))
else: # pragma: no cover
raise AssertionError(f"Axis must be 0 or 1. Got {axis}")
return self._constructor(new_data)
def to_period(self, freq=None, axis=0, copy=True) -> "DataFrame":
"""
Convert DataFrame from DatetimeIndex to PeriodIndex.
Convert DataFrame from DatetimeIndex to PeriodIndex with desired
frequency (inferred from index if not passed).
Parameters
----------
freq : str, default
Frequency of the PeriodIndex.
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to convert (the index by default).
copy : bool, default True
If False then underlying input data is not copied.
Returns
-------
TimeSeries with PeriodIndex
"""
new_data = self._data
if copy:
new_data = new_data.copy()
axis = self._get_axis_number(axis)
if axis == 0:
new_data.set_axis(1, self.index.to_period(freq=freq))
elif axis == 1:
new_data.set_axis(0, self.columns.to_period(freq=freq))
else: # pragma: no cover
raise AssertionError(f"Axis must be 0 or 1. Got {axis}")
return self._constructor(new_data)
def isin(self, values) -> "DataFrame":
"""
Whether each element in the DataFrame is contained in values.
Parameters
----------
values : iterable, Series, DataFrame or dict
The result will only be true at a location if all the
labels match. If `values` is a Series, that's the index. If
`values` is a dict, the keys must be the column names,
which must match. If `values` is a DataFrame,
then both the index and column labels must match.
Returns
-------
DataFrame
DataFrame of booleans showing whether each element in the DataFrame
is contained in values.
See Also
--------
DataFrame.eq: Equality test for DataFrame.
Series.isin: Equivalent method on Series.
Series.str.contains: Test if pattern or regex is contained within a
string of a Series or Index.
Examples
--------
>>> df = pd.DataFrame({'num_legs': [2, 4], 'num_wings': [2, 0]},
... index=['falcon', 'dog'])
>>> df
num_legs num_wings
falcon 2 2
dog 4 0
When ``values`` is a list check whether every value in the DataFrame
is present in the list (which animals have 0 or 2 legs or wings)
>>> df.isin([0, 2])
num_legs num_wings
falcon True True
dog False True
When ``values`` is a dict, we can pass values to check for each
column separately:
>>> df.isin({'num_wings': [0, 3]})
num_legs num_wings
falcon False False
dog False True
When ``values`` is a Series or DataFrame the index and column must
match. Note that 'falcon' does not match based on the number of legs
in df2.
>>> other = pd.DataFrame({'num_legs': [8, 2], 'num_wings': [0, 2]},
... index=['spider', 'falcon'])
>>> df.isin(other)
num_legs num_wings
falcon True True
dog False False
"""
if isinstance(values, dict):
from pandas.core.reshape.concat import concat
values = collections.defaultdict(list, values)
return self._ensure_type(
concat(
(
self.iloc[:, [i]].isin(values[col])
for i, col in enumerate(self.columns)
),
axis=1,
)
)
elif isinstance(values, Series):
if not values.index.is_unique:
raise ValueError("cannot compute isin with a duplicate axis.")
return self.eq(values.reindex_like(self), axis="index")
elif isinstance(values, DataFrame):
if not (values.columns.is_unique and values.index.is_unique):
raise ValueError("cannot compute isin with a duplicate axis.")
return self.eq(values.reindex_like(self))
else:
if not is_list_like(values):
raise TypeError(
"only list-like or dict-like objects are allowed "
"to be passed to DataFrame.isin(), "
f"you passed a '{type(values).__name__}'"
)
return DataFrame(
algorithms.isin(self.values.ravel(), values).reshape(self.shape),
self.index,
self.columns,
)
# ----------------------------------------------------------------------
# Add plotting methods to DataFrame
plot = CachedAccessor("plot", pandas.plotting.PlotAccessor)
hist = pandas.plotting.hist_frame
boxplot = pandas.plotting.boxplot_frame
sparse = CachedAccessor("sparse", SparseFrameAccessor)
DataFrame._setup_axes(
["index", "columns"],
docs={
"index": "The index (row labels) of the DataFrame.",
"columns": "The column labels of the DataFrame.",
},
)
DataFrame._add_numeric_operations()
DataFrame._add_series_or_dataframe_operations()
ops.add_flex_arithmetic_methods(DataFrame)
ops.add_special_arithmetic_methods(DataFrame)
def _from_nested_dict(data):
# TODO: this should be seriously cythonized
new_data = {}
for index, s in data.items():
for col, v in s.items():
new_data[col] = new_data.get(col, {})
new_data[col][index] = v
return new_data
def _put_str(s, space):
return str(s)[:space].ljust(space)
| BugsInPy/BugsInPy/temp/projects/pandas/bug-78-fixed/pandas/pandas/core/frame.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-78-buggy/pandas/pandas/core/frame.py |
pandas-bug-95 | from datetime import timedelta
import operator
from typing import Any, Callable, List, Optional, Sequence, Union
import numpy as np
from pandas._libs.tslibs import (
NaT,
NaTType,
frequencies as libfrequencies,
iNaT,
period as libperiod,
)
from pandas._libs.tslibs.fields import isleapyear_arr
from pandas._libs.tslibs.period import (
DIFFERENT_FREQ,
IncompatibleFrequency,
Period,
get_period_field_arr,
period_asfreq_arr,
)
from pandas._libs.tslibs.timedeltas import Timedelta, delta_to_nanoseconds
import pandas.compat as compat
from pandas.util._decorators import Appender, cache_readonly
from pandas.core.dtypes.common import (
_TD_DTYPE,
ensure_object,
is_datetime64_dtype,
is_float_dtype,
is_list_like,
is_object_dtype,
is_period_dtype,
pandas_dtype,
)
from pandas.core.dtypes.dtypes import PeriodDtype
from pandas.core.dtypes.generic import (
ABCIndexClass,
ABCPeriodArray,
ABCPeriodIndex,
ABCSeries,
)
from pandas.core.dtypes.missing import isna, notna
from pandas.core import ops
import pandas.core.algorithms as algos
from pandas.core.arrays import datetimelike as dtl
import pandas.core.common as com
from pandas.core.ops.common import unpack_zerodim_and_defer
from pandas.core.ops.invalid import invalid_comparison
from pandas.tseries import frequencies
from pandas.tseries.offsets import DateOffset, Tick, _delta_to_tick
def _field_accessor(name, alias, docstring=None):
def f(self):
base, mult = libfrequencies.get_freq_code(self.freq)
result = get_period_field_arr(alias, self.asi8, base)
return result
f.__name__ = name
f.__doc__ = docstring
return property(f)
def _period_array_cmp(cls, op):
"""
Wrap comparison operations to convert Period-like to PeriodDtype
"""
opname = f"__{op.__name__}__"
nat_result = opname == "__ne__"
@unpack_zerodim_and_defer(opname)
def wrapper(self, other):
ordinal_op = getattr(self.asi8, opname)
if isinstance(other, str):
try:
other = self._scalar_from_string(other)
except ValueError:
# string that can't be parsed as Period
return invalid_comparison(self, other, op)
elif isinstance(other, int):
# TODO: sure we want to allow this? we dont for DTA/TDA
# 2 tests rely on this
other = Period(other, freq=self.freq)
result = ordinal_op(other.ordinal)
if isinstance(other, self._recognized_scalars) or other is NaT:
other = self._scalar_type(other)
self._check_compatible_with(other)
other_i8 = self._unbox_scalar(other)
result = op(self.view("i8"), other_i8)
if isna(other):
result.fill(nat_result)
elif not is_list_like(other):
return invalid_comparison(self, other, op)
elif len(other) != len(self):
raise ValueError("Lengths must match")
else:
if isinstance(other, list):
# TODO: could use pd.Index to do inference?
other = np.array(other)
if not isinstance(other, (np.ndarray, cls)):
return invalid_comparison(self, other, op)
if is_object_dtype(other):
with np.errstate(all="ignore"):
result = ops.comp_method_OBJECT_ARRAY(
op, self.astype(object), other
)
o_mask = isna(other)
elif not cls._is_recognized_dtype(other.dtype):
# e.g. is_timedelta64_dtype(other)
return invalid_comparison(self, other, op)
else:
assert isinstance(other, cls), type(other)
self._check_compatible_with(other)
result = op(self.view("i8"), other.view("i8"))
o_mask = other._isnan
if o_mask.any():
result[o_mask] = nat_result
if self._hasnans:
result[self._isnan] = nat_result
return result
return compat.set_function_name(wrapper, opname, cls)
class PeriodArray(dtl.DatetimeLikeArrayMixin, dtl.DatelikeOps):
"""
Pandas ExtensionArray for storing Period data.
Users should use :func:`period_array` to create new instances.
Parameters
----------
values : Union[PeriodArray, Series[period], ndarray[int], PeriodIndex]
The data to store. These should be arrays that can be directly
converted to ordinals without inference or copy (PeriodArray,
ndarray[int64]), or a box around such an array (Series[period],
PeriodIndex).
freq : str or DateOffset
The `freq` to use for the array. Mostly applicable when `values`
is an ndarray of integers, when `freq` is required. When `values`
is a PeriodArray (or box around), it's checked that ``values.freq``
matches `freq`.
dtype : PeriodDtype, optional
A PeriodDtype instance from which to extract a `freq`. If both
`freq` and `dtype` are specified, then the frequencies must match.
copy : bool, default False
Whether to copy the ordinals before storing.
Attributes
----------
None
Methods
-------
None
See Also
--------
period_array : Create a new PeriodArray.
PeriodIndex : Immutable Index for period data.
Notes
-----
There are two components to a PeriodArray
- ordinals : integer ndarray
- freq : pd.tseries.offsets.Offset
The values are physically stored as a 1-D ndarray of integers. These are
called "ordinals" and represent some kind of offset from a base.
The `freq` indicates the span covered by each element of the array.
All elements in the PeriodArray have the same `freq`.
"""
# array priority higher than numpy scalars
__array_priority__ = 1000
_typ = "periodarray" # ABCPeriodArray
_scalar_type = Period
_recognized_scalars = (Period,)
_is_recognized_dtype = is_period_dtype
# Names others delegate to us
_other_ops: List[str] = []
_bool_ops = ["is_leap_year"]
_object_ops = ["start_time", "end_time", "freq"]
_field_ops = [
"year",
"month",
"day",
"hour",
"minute",
"second",
"weekofyear",
"weekday",
"week",
"dayofweek",
"dayofyear",
"quarter",
"qyear",
"days_in_month",
"daysinmonth",
]
_datetimelike_ops = _field_ops + _object_ops + _bool_ops
_datetimelike_methods = ["strftime", "to_timestamp", "asfreq"]
# --------------------------------------------------------------------
# Constructors
def __init__(self, values, freq=None, dtype=None, copy=False):
freq = validate_dtype_freq(dtype, freq)
if freq is not None:
freq = Period._maybe_convert_freq(freq)
if isinstance(values, ABCSeries):
values = values._values
if not isinstance(values, type(self)):
raise TypeError("Incorrect dtype")
elif isinstance(values, ABCPeriodIndex):
values = values._values
if isinstance(values, type(self)):
if freq is not None and freq != values.freq:
raise raise_on_incompatible(values, freq)
values, freq = values._data, values.freq
values = np.array(values, dtype="int64", copy=copy)
self._data = values
if freq is None:
raise ValueError("freq is not specified and cannot be inferred")
self._dtype = PeriodDtype(freq)
@classmethod
def _simple_new(cls, values, freq=None, **kwargs):
# alias for PeriodArray.__init__
return cls(values, freq=freq, **kwargs)
@classmethod
def _from_sequence(
cls,
scalars: Sequence[Optional[Period]],
dtype: Optional[PeriodDtype] = None,
copy: bool = False,
) -> ABCPeriodArray:
if dtype:
freq = dtype.freq
else:
freq = None
if isinstance(scalars, cls):
validate_dtype_freq(scalars.dtype, freq)
if copy:
scalars = scalars.copy()
return scalars
periods = np.asarray(scalars, dtype=object)
if copy:
periods = periods.copy()
freq = freq or libperiod.extract_freq(periods)
ordinals = libperiod.extract_ordinals(periods, freq)
return cls(ordinals, freq=freq)
@classmethod
def _from_sequence_of_strings(cls, strings, dtype=None, copy=False):
return cls._from_sequence(strings, dtype, copy)
@classmethod
def _from_datetime64(cls, data, freq, tz=None):
"""
Construct a PeriodArray from a datetime64 array
Parameters
----------
data : ndarray[datetime64[ns], datetime64[ns, tz]]
freq : str or Tick
tz : tzinfo, optional
Returns
-------
PeriodArray[freq]
"""
data, freq = dt64arr_to_periodarr(data, freq, tz)
return cls(data, freq=freq)
@classmethod
def _generate_range(cls, start, end, periods, freq, fields):
periods = dtl.validate_periods(periods)
if freq is not None:
freq = Period._maybe_convert_freq(freq)
field_count = len(fields)
if start is not None or end is not None:
if field_count > 0:
raise ValueError(
"Can either instantiate from fields or endpoints, but not both"
)
subarr, freq = _get_ordinal_range(start, end, periods, freq)
elif field_count > 0:
subarr, freq = _range_from_fields(freq=freq, **fields)
else:
raise ValueError("Not enough parameters to construct Period range")
return subarr, freq
# -----------------------------------------------------------------
# DatetimeLike Interface
def _unbox_scalar(self, value: Union[Period, NaTType]) -> int:
if value is NaT:
return value.value
elif isinstance(value, self._scalar_type):
if not isna(value):
self._check_compatible_with(value)
return value.ordinal
else:
raise ValueError(f"'value' should be a Period. Got '{value}' instead.")
def _scalar_from_string(self, value: str) -> Period:
return Period(value, freq=self.freq)
def _check_compatible_with(self, other, setitem: bool = False):
if other is NaT:
return
if self.freqstr != other.freqstr:
raise raise_on_incompatible(self, other)
# --------------------------------------------------------------------
# Data / Attributes
@cache_readonly
def dtype(self):
return self._dtype
# error: Read-only property cannot override read-write property [misc]
@property # type: ignore
def freq(self):
"""
Return the frequency object for this PeriodArray.
"""
return self.dtype.freq
def __array__(self, dtype=None):
# overriding DatetimelikeArray
return np.array(list(self), dtype=object)
# --------------------------------------------------------------------
# Vectorized analogues of Period properties
year = _field_accessor(
"year",
0,
"""
The year of the period.
""",
)
month = _field_accessor(
"month",
3,
"""
The month as January=1, December=12.
""",
)
day = _field_accessor(
"day",
4,
"""
The days of the period.
""",
)
hour = _field_accessor(
"hour",
5,
"""
The hour of the period.
""",
)
minute = _field_accessor(
"minute",
6,
"""
The minute of the period.
""",
)
second = _field_accessor(
"second",
7,
"""
The second of the period.
""",
)
weekofyear = _field_accessor(
"week",
8,
"""
The week ordinal of the year.
""",
)
week = weekofyear
dayofweek = _field_accessor(
"dayofweek",
10,
"""
The day of the week with Monday=0, Sunday=6.
""",
)
weekday = dayofweek
dayofyear = day_of_year = _field_accessor(
"dayofyear",
9,
"""
The ordinal day of the year.
""",
)
quarter = _field_accessor(
"quarter",
2,
"""
The quarter of the date.
""",
)
qyear = _field_accessor("qyear", 1)
days_in_month = _field_accessor(
"days_in_month",
11,
"""
The number of days in the month.
""",
)
daysinmonth = days_in_month
@property
def is_leap_year(self):
"""
Logical indicating if the date belongs to a leap year.
"""
return isleapyear_arr(np.asarray(self.year))
@property
def start_time(self):
return self.to_timestamp(how="start")
@property
def end_time(self):
return self.to_timestamp(how="end")
def to_timestamp(self, freq=None, how="start"):
"""
Cast to DatetimeArray/Index.
Parameters
----------
freq : str or DateOffset, optional
Target frequency. The default is 'D' for week or longer,
'S' otherwise.
how : {'s', 'e', 'start', 'end'}
Whether to use the start or end of the time period being converted.
Returns
-------
DatetimeArray/Index
"""
from pandas.core.arrays import DatetimeArray
how = libperiod._validate_end_alias(how)
end = how == "E"
if end:
if freq == "B":
# roll forward to ensure we land on B date
adjust = Timedelta(1, "D") - Timedelta(1, "ns")
return self.to_timestamp(how="start") + adjust
else:
adjust = Timedelta(1, "ns")
return (self + self.freq).to_timestamp(how="start") - adjust
if freq is None:
base, mult = libfrequencies.get_freq_code(self.freq)
freq = libfrequencies.get_to_timestamp_base(base)
else:
freq = Period._maybe_convert_freq(freq)
base, mult = libfrequencies.get_freq_code(freq)
new_data = self.asfreq(freq, how=how)
new_data = libperiod.periodarr_to_dt64arr(new_data.asi8, base)
return DatetimeArray._from_sequence(new_data, freq="infer")
# --------------------------------------------------------------------
# Array-like / EA-Interface Methods
@Appender(dtl.DatetimeLikeArrayMixin._validate_fill_value.__doc__)
def _validate_fill_value(self, fill_value):
if isna(fill_value):
fill_value = iNaT
elif isinstance(fill_value, Period):
self._check_compatible_with(fill_value)
fill_value = fill_value.ordinal
else:
raise ValueError(f"'fill_value' should be a Period. Got '{fill_value}'.")
return fill_value
def _values_for_argsort(self):
return self._data
# --------------------------------------------------------------------
def _time_shift(self, periods, freq=None):
"""
Shift each value by `periods`.
Note this is different from ExtensionArray.shift, which
shifts the *position* of each element, padding the end with
missing values.
Parameters
----------
periods : int
Number of periods to shift by.
freq : pandas.DateOffset, pandas.Timedelta, or str
Frequency increment to shift by.
"""
if freq is not None:
raise TypeError(
"`freq` argument is not supported for "
f"{type(self).__name__}._time_shift"
)
values = self.asi8 + periods * self.freq.n
if self._hasnans:
values[self._isnan] = iNaT
return type(self)(values, freq=self.freq)
@property
def _box_func(self):
return lambda x: Period._from_ordinal(ordinal=x, freq=self.freq)
def asfreq(self, freq=None, how="E"):
"""
Convert the Period Array/Index to the specified frequency `freq`.
Parameters
----------
freq : str
A frequency.
how : str {'E', 'S'}
Whether the elements should be aligned to the end
or start within pa period.
* 'E', 'END', or 'FINISH' for end,
* 'S', 'START', or 'BEGIN' for start.
January 31st ('END') vs. January 1st ('START') for example.
Returns
-------
Period Array/Index
Constructed with the new frequency.
Examples
--------
>>> pidx = pd.period_range('2010-01-01', '2015-01-01', freq='A')
>>> pidx
PeriodIndex(['2010', '2011', '2012', '2013', '2014', '2015'],
dtype='period[A-DEC]', freq='A-DEC')
>>> pidx.asfreq('M')
PeriodIndex(['2010-12', '2011-12', '2012-12', '2013-12', '2014-12',
'2015-12'], dtype='period[M]', freq='M')
>>> pidx.asfreq('M', how='S')
PeriodIndex(['2010-01', '2011-01', '2012-01', '2013-01', '2014-01',
'2015-01'], dtype='period[M]', freq='M')
"""
how = libperiod._validate_end_alias(how)
freq = Period._maybe_convert_freq(freq)
base1, mult1 = libfrequencies.get_freq_code(self.freq)
base2, mult2 = libfrequencies.get_freq_code(freq)
asi8 = self.asi8
# mult1 can't be negative or 0
end = how == "E"
if end:
ordinal = asi8 + mult1 - 1
else:
ordinal = asi8
new_data = period_asfreq_arr(ordinal, base1, base2, end)
if self._hasnans:
new_data[self._isnan] = iNaT
return type(self)(new_data, freq=freq)
# ------------------------------------------------------------------
# Rendering Methods
def _formatter(self, boxed=False):
if boxed:
return str
return "'{}'".format
def _format_native_types(self, na_rep="NaT", date_format=None, **kwargs):
"""
actually format my specific types
"""
values = self.astype(object)
if date_format:
formatter = lambda dt: dt.strftime(date_format)
else:
formatter = lambda dt: str(dt)
if self._hasnans:
mask = self._isnan
values[mask] = na_rep
imask = ~mask
values[imask] = np.array([formatter(dt) for dt in values[imask]])
else:
values = np.array([formatter(dt) for dt in values])
return values
# ------------------------------------------------------------------
def astype(self, dtype, copy=True):
# We handle Period[T] -> Period[U]
# Our parent handles everything else.
dtype = pandas_dtype(dtype)
if is_period_dtype(dtype):
return self.asfreq(dtype.freq)
return super().astype(dtype, copy=copy)
# ------------------------------------------------------------------
# Arithmetic Methods
_create_comparison_method = classmethod(_period_array_cmp)
def _sub_datelike(self, other):
assert other is not NaT
return NotImplemented
def _sub_period(self, other):
# If the operation is well-defined, we return an object-Index
# of DateOffsets. Null entries are filled with pd.NaT
self._check_compatible_with(other)
asi8 = self.asi8
new_data = asi8 - other.ordinal
new_data = np.array([self.freq * x for x in new_data])
if self._hasnans:
new_data[self._isnan] = NaT
return new_data
def _addsub_int_array(
self, other: np.ndarray, op: Callable[[Any, Any], Any],
) -> "PeriodArray":
"""
Add or subtract array of integers; equivalent to applying
`_time_shift` pointwise.
Parameters
----------
other : np.ndarray[integer-dtype]
op : {operator.add, operator.sub}
Returns
-------
result : PeriodArray
"""
assert op in [operator.add, operator.sub]
if op is operator.sub:
other = -other
res_values = algos.checked_add_with_arr(self.asi8, other, arr_mask=self._isnan)
res_values = res_values.view("i8")
res_values[self._isnan] = iNaT
return type(self)(res_values, freq=self.freq)
def _add_offset(self, other):
assert not isinstance(other, Tick)
base = libfrequencies.get_base_alias(other.rule_code)
if base != self.freq.rule_code:
raise raise_on_incompatible(self, other)
# Note: when calling parent class's _add_timedeltalike_scalar,
# it will call delta_to_nanoseconds(delta). Because delta here
# is an integer, delta_to_nanoseconds will return it unchanged.
result = super()._add_timedeltalike_scalar(other.n)
return type(self)(result, freq=self.freq)
def _add_timedeltalike_scalar(self, other):
"""
Parameters
----------
other : timedelta, Tick, np.timedelta64
Returns
-------
result : ndarray[int64]
"""
assert isinstance(self.freq, Tick) # checked by calling function
assert isinstance(other, (timedelta, np.timedelta64, Tick))
if notna(other):
# special handling for np.timedelta64("NaT"), avoid calling
# _check_timedeltalike_freq_compat as that would raise TypeError
other = self._check_timedeltalike_freq_compat(other)
# Note: when calling parent class's _add_timedeltalike_scalar,
# it will call delta_to_nanoseconds(delta). Because delta here
# is an integer, delta_to_nanoseconds will return it unchanged.
ordinals = super()._add_timedeltalike_scalar(other)
return ordinals
def _add_delta_tdi(self, other):
"""
Parameters
----------
other : TimedeltaArray or ndarray[timedelta64]
Returns
-------
result : ndarray[int64]
"""
assert isinstance(self.freq, Tick) # checked by calling function
if not np.all(isna(other)):
delta = self._check_timedeltalike_freq_compat(other)
else:
# all-NaT TimedeltaIndex is equivalent to a single scalar td64 NaT
return self + np.timedelta64("NaT")
return self._addsub_int_array(delta, operator.add).asi8
def _add_delta(self, other):
"""
Add a timedelta-like, Tick, or TimedeltaIndex-like object
to self, yielding a new PeriodArray
Parameters
----------
other : {timedelta, np.timedelta64, Tick,
TimedeltaIndex, ndarray[timedelta64]}
Returns
-------
result : PeriodArray
"""
if not isinstance(self.freq, Tick):
# We cannot add timedelta-like to non-tick PeriodArray
raise raise_on_incompatible(self, other)
new_ordinals = super()._add_delta(other)
return type(self)(new_ordinals, freq=self.freq)
def _check_timedeltalike_freq_compat(self, other):
"""
Arithmetic operations with timedelta-like scalars or array `other`
are only valid if `other` is an integer multiple of `self.freq`.
If the operation is valid, find that integer multiple. Otherwise,
raise because the operation is invalid.
Parameters
----------
other : timedelta, np.timedelta64, Tick,
ndarray[timedelta64], TimedeltaArray, TimedeltaIndex
Returns
-------
multiple : int or ndarray[int64]
Raises
------
IncompatibleFrequency
"""
assert isinstance(self.freq, Tick) # checked by calling function
own_offset = frequencies.to_offset(self.freq.rule_code)
base_nanos = delta_to_nanoseconds(own_offset)
if isinstance(other, (timedelta, np.timedelta64, Tick)):
nanos = delta_to_nanoseconds(other)
elif isinstance(other, np.ndarray):
# numpy timedelta64 array; all entries must be compatible
assert other.dtype.kind == "m"
if other.dtype != _TD_DTYPE:
# i.e. non-nano unit
# TODO: disallow unit-less timedelta64
other = other.astype(_TD_DTYPE)
nanos = other.view("i8")
else:
# TimedeltaArray/Index
nanos = other.asi8
if np.all(nanos % base_nanos == 0):
# nanos being added is an integer multiple of the
# base-frequency to self.freq
delta = nanos // base_nanos
# delta is the integer (or integer-array) number of periods
# by which will be added to self.
return delta
raise raise_on_incompatible(self, other)
PeriodArray._add_comparison_ops()
def raise_on_incompatible(left, right):
"""
Helper function to render a consistent error message when raising
IncompatibleFrequency.
Parameters
----------
left : PeriodArray
right : None, DateOffset, Period, ndarray, or timedelta-like
Returns
------
IncompatibleFrequency
Exception to be raised by the caller.
"""
# GH#24283 error message format depends on whether right is scalar
if isinstance(right, np.ndarray) or right is None:
other_freq = None
elif isinstance(right, (ABCPeriodIndex, PeriodArray, Period, DateOffset)):
other_freq = right.freqstr
else:
other_freq = _delta_to_tick(Timedelta(right)).freqstr
msg = DIFFERENT_FREQ.format(
cls=type(left).__name__, own_freq=left.freqstr, other_freq=other_freq
)
return IncompatibleFrequency(msg)
# -------------------------------------------------------------------
# Constructor Helpers
def period_array(
data: Sequence[Optional[Period]],
freq: Optional[Union[str, Tick]] = None,
copy: bool = False,
) -> PeriodArray:
"""
Construct a new PeriodArray from a sequence of Period scalars.
Parameters
----------
data : Sequence of Period objects
A sequence of Period objects. These are required to all have
the same ``freq.`` Missing values can be indicated by ``None``
or ``pandas.NaT``.
freq : str, Tick, or Offset
The frequency of every element of the array. This can be specified
to avoid inferring the `freq` from `data`.
copy : bool, default False
Whether to ensure a copy of the data is made.
Returns
-------
PeriodArray
See Also
--------
PeriodArray
pandas.PeriodIndex
Examples
--------
>>> period_array([pd.Period('2017', freq='A'),
... pd.Period('2018', freq='A')])
<PeriodArray>
['2017', '2018']
Length: 2, dtype: period[A-DEC]
>>> period_array([pd.Period('2017', freq='A'),
... pd.Period('2018', freq='A'),
... pd.NaT])
<PeriodArray>
['2017', '2018', 'NaT']
Length: 3, dtype: period[A-DEC]
Integers that look like years are handled
>>> period_array([2000, 2001, 2002], freq='D')
['2000-01-01', '2001-01-01', '2002-01-01']
Length: 3, dtype: period[D]
Datetime-like strings may also be passed
>>> period_array(['2000-Q1', '2000-Q2', '2000-Q3', '2000-Q4'], freq='Q')
<PeriodArray>
['2000Q1', '2000Q2', '2000Q3', '2000Q4']
Length: 4, dtype: period[Q-DEC]
"""
if is_datetime64_dtype(data):
return PeriodArray._from_datetime64(data, freq)
if isinstance(data, (ABCPeriodIndex, ABCSeries, PeriodArray)):
return PeriodArray(data, freq)
# other iterable of some kind
if not isinstance(data, (np.ndarray, list, tuple)):
data = list(data)
data = np.asarray(data)
dtype: Optional[PeriodDtype]
if freq:
dtype = PeriodDtype(freq)
else:
dtype = None
if is_float_dtype(data) and len(data) > 0:
raise TypeError("PeriodIndex does not allow floating point in construction")
data = ensure_object(data)
return PeriodArray._from_sequence(data, dtype=dtype)
def validate_dtype_freq(dtype, freq):
"""
If both a dtype and a freq are available, ensure they match. If only
dtype is available, extract the implied freq.
Parameters
----------
dtype : dtype
freq : DateOffset or None
Returns
-------
freq : DateOffset
Raises
------
ValueError : non-period dtype
IncompatibleFrequency : mismatch between dtype and freq
"""
if freq is not None:
freq = frequencies.to_offset(freq)
if dtype is not None:
dtype = pandas_dtype(dtype)
if not is_period_dtype(dtype):
raise ValueError("dtype must be PeriodDtype")
if freq is None:
freq = dtype.freq
elif freq != dtype.freq:
raise IncompatibleFrequency("specified freq and dtype are different")
return freq
def dt64arr_to_periodarr(data, freq, tz=None):
"""
Convert an datetime-like array to values Period ordinals.
Parameters
----------
data : Union[Series[datetime64[ns]], DatetimeIndex, ndarray[datetime64ns]]
freq : Optional[Union[str, Tick]]
Must match the `freq` on the `data` if `data` is a DatetimeIndex
or Series.
tz : Optional[tzinfo]
Returns
-------
ordinals : ndarray[int]
freq : Tick
The frequency extracted from the Series or DatetimeIndex if that's
used.
"""
if data.dtype != np.dtype("M8[ns]"):
raise ValueError(f"Wrong dtype: {data.dtype}")
if freq is None:
if isinstance(data, ABCIndexClass):
data, freq = data._values, data.freq
elif isinstance(data, ABCSeries):
data, freq = data._values, data.dt.freq
freq = Period._maybe_convert_freq(freq)
if isinstance(data, (ABCIndexClass, ABCSeries)):
data = data._values
base, mult = libfrequencies.get_freq_code(freq)
return libperiod.dt64arr_to_periodarr(data.view("i8"), base, tz), freq
def _get_ordinal_range(start, end, periods, freq, mult=1):
if com.count_not_none(start, end, periods) != 2:
raise ValueError(
"Of the three parameters: start, end, and periods, "
"exactly two must be specified"
)
if freq is not None:
_, mult = libfrequencies.get_freq_code(freq)
if start is not None:
start = Period(start, freq)
if end is not None:
end = Period(end, freq)
is_start_per = isinstance(start, Period)
is_end_per = isinstance(end, Period)
if is_start_per and is_end_per and start.freq != end.freq:
raise ValueError("start and end must have same freq")
if start is NaT or end is NaT:
raise ValueError("start and end must not be NaT")
if freq is None:
if is_start_per:
freq = start.freq
elif is_end_per:
freq = end.freq
else: # pragma: no cover
raise ValueError("Could not infer freq from start/end")
if periods is not None:
periods = periods * mult
if start is None:
data = np.arange(
end.ordinal - periods + mult, end.ordinal + 1, mult, dtype=np.int64
)
else:
data = np.arange(
start.ordinal, start.ordinal + periods, mult, dtype=np.int64
)
else:
data = np.arange(start.ordinal, end.ordinal + 1, mult, dtype=np.int64)
return data, freq
def _range_from_fields(
year=None,
month=None,
quarter=None,
day=None,
hour=None,
minute=None,
second=None,
freq=None,
):
if hour is None:
hour = 0
if minute is None:
minute = 0
if second is None:
second = 0
if day is None:
day = 1
ordinals = []
if quarter is not None:
if freq is None:
freq = "Q"
base = libfrequencies.FreqGroup.FR_QTR
else:
base, mult = libfrequencies.get_freq_code(freq)
if base != libfrequencies.FreqGroup.FR_QTR:
raise AssertionError("base must equal FR_QTR")
year, quarter = _make_field_arrays(year, quarter)
for y, q in zip(year, quarter):
y, m = libperiod.quarter_to_myear(y, q, freq)
val = libperiod.period_ordinal(y, m, 1, 1, 1, 1, 0, 0, base)
ordinals.append(val)
else:
base, mult = libfrequencies.get_freq_code(freq)
arrays = _make_field_arrays(year, month, day, hour, minute, second)
for y, mth, d, h, mn, s in zip(*arrays):
ordinals.append(libperiod.period_ordinal(y, mth, d, h, mn, s, 0, 0, base))
return np.array(ordinals, dtype=np.int64), freq
def _make_field_arrays(*fields):
length = None
for x in fields:
if isinstance(x, (list, np.ndarray, ABCSeries)):
if length is not None and len(x) != length:
raise ValueError("Mismatched Period array lengths")
elif length is None:
length = len(x)
arrays = [
np.asarray(x)
if isinstance(x, (np.ndarray, list, ABCSeries))
else np.repeat(x, length)
for x in fields
]
return arrays
from datetime import timedelta
import operator
from typing import Any, Callable, List, Optional, Sequence, Union
import numpy as np
from pandas._libs.tslibs import (
NaT,
NaTType,
frequencies as libfrequencies,
iNaT,
period as libperiod,
)
from pandas._libs.tslibs.fields import isleapyear_arr
from pandas._libs.tslibs.period import (
DIFFERENT_FREQ,
IncompatibleFrequency,
Period,
get_period_field_arr,
period_asfreq_arr,
)
from pandas._libs.tslibs.timedeltas import Timedelta, delta_to_nanoseconds
import pandas.compat as compat
from pandas.util._decorators import Appender, cache_readonly
from pandas.core.dtypes.common import (
_TD_DTYPE,
ensure_object,
is_datetime64_dtype,
is_float_dtype,
is_list_like,
is_object_dtype,
is_period_dtype,
pandas_dtype,
)
from pandas.core.dtypes.dtypes import PeriodDtype
from pandas.core.dtypes.generic import (
ABCIndexClass,
ABCPeriodArray,
ABCPeriodIndex,
ABCSeries,
)
from pandas.core.dtypes.missing import isna, notna
from pandas.core import ops
import pandas.core.algorithms as algos
from pandas.core.arrays import datetimelike as dtl
import pandas.core.common as com
from pandas.core.ops.common import unpack_zerodim_and_defer
from pandas.core.ops.invalid import invalid_comparison
from pandas.tseries import frequencies
from pandas.tseries.offsets import DateOffset, Tick, _delta_to_tick
def _field_accessor(name, alias, docstring=None):
def f(self):
base, mult = libfrequencies.get_freq_code(self.freq)
result = get_period_field_arr(alias, self.asi8, base)
return result
f.__name__ = name
f.__doc__ = docstring
return property(f)
def _period_array_cmp(cls, op):
"""
Wrap comparison operations to convert Period-like to PeriodDtype
"""
opname = f"__{op.__name__}__"
nat_result = opname == "__ne__"
@unpack_zerodim_and_defer(opname)
def wrapper(self, other):
if isinstance(other, str):
try:
other = self._scalar_from_string(other)
except ValueError:
# string that can't be parsed as Period
return invalid_comparison(self, other, op)
if isinstance(other, self._recognized_scalars) or other is NaT:
other = self._scalar_type(other)
self._check_compatible_with(other)
other_i8 = self._unbox_scalar(other)
result = op(self.view("i8"), other_i8)
if isna(other):
result.fill(nat_result)
elif not is_list_like(other):
return invalid_comparison(self, other, op)
elif len(other) != len(self):
raise ValueError("Lengths must match")
else:
if isinstance(other, list):
# TODO: could use pd.Index to do inference?
other = np.array(other)
if not isinstance(other, (np.ndarray, cls)):
return invalid_comparison(self, other, op)
if is_object_dtype(other):
with np.errstate(all="ignore"):
result = ops.comp_method_OBJECT_ARRAY(
op, self.astype(object), other
)
o_mask = isna(other)
elif not cls._is_recognized_dtype(other.dtype):
# e.g. is_timedelta64_dtype(other)
return invalid_comparison(self, other, op)
else:
assert isinstance(other, cls), type(other)
self._check_compatible_with(other)
result = op(self.view("i8"), other.view("i8"))
o_mask = other._isnan
if o_mask.any():
result[o_mask] = nat_result
if self._hasnans:
result[self._isnan] = nat_result
return result
return compat.set_function_name(wrapper, opname, cls)
class PeriodArray(dtl.DatetimeLikeArrayMixin, dtl.DatelikeOps):
"""
Pandas ExtensionArray for storing Period data.
Users should use :func:`period_array` to create new instances.
Parameters
----------
values : Union[PeriodArray, Series[period], ndarray[int], PeriodIndex]
The data to store. These should be arrays that can be directly
converted to ordinals without inference or copy (PeriodArray,
ndarray[int64]), or a box around such an array (Series[period],
PeriodIndex).
freq : str or DateOffset
The `freq` to use for the array. Mostly applicable when `values`
is an ndarray of integers, when `freq` is required. When `values`
is a PeriodArray (or box around), it's checked that ``values.freq``
matches `freq`.
dtype : PeriodDtype, optional
A PeriodDtype instance from which to extract a `freq`. If both
`freq` and `dtype` are specified, then the frequencies must match.
copy : bool, default False
Whether to copy the ordinals before storing.
Attributes
----------
None
Methods
-------
None
See Also
--------
period_array : Create a new PeriodArray.
PeriodIndex : Immutable Index for period data.
Notes
-----
There are two components to a PeriodArray
- ordinals : integer ndarray
- freq : pd.tseries.offsets.Offset
The values are physically stored as a 1-D ndarray of integers. These are
called "ordinals" and represent some kind of offset from a base.
The `freq` indicates the span covered by each element of the array.
All elements in the PeriodArray have the same `freq`.
"""
# array priority higher than numpy scalars
__array_priority__ = 1000
_typ = "periodarray" # ABCPeriodArray
_scalar_type = Period
_recognized_scalars = (Period,)
_is_recognized_dtype = is_period_dtype
# Names others delegate to us
_other_ops: List[str] = []
_bool_ops = ["is_leap_year"]
_object_ops = ["start_time", "end_time", "freq"]
_field_ops = [
"year",
"month",
"day",
"hour",
"minute",
"second",
"weekofyear",
"weekday",
"week",
"dayofweek",
"dayofyear",
"quarter",
"qyear",
"days_in_month",
"daysinmonth",
]
_datetimelike_ops = _field_ops + _object_ops + _bool_ops
_datetimelike_methods = ["strftime", "to_timestamp", "asfreq"]
# --------------------------------------------------------------------
# Constructors
def __init__(self, values, freq=None, dtype=None, copy=False):
freq = validate_dtype_freq(dtype, freq)
if freq is not None:
freq = Period._maybe_convert_freq(freq)
if isinstance(values, ABCSeries):
values = values._values
if not isinstance(values, type(self)):
raise TypeError("Incorrect dtype")
elif isinstance(values, ABCPeriodIndex):
values = values._values
if isinstance(values, type(self)):
if freq is not None and freq != values.freq:
raise raise_on_incompatible(values, freq)
values, freq = values._data, values.freq
values = np.array(values, dtype="int64", copy=copy)
self._data = values
if freq is None:
raise ValueError("freq is not specified and cannot be inferred")
self._dtype = PeriodDtype(freq)
@classmethod
def _simple_new(cls, values, freq=None, **kwargs):
# alias for PeriodArray.__init__
return cls(values, freq=freq, **kwargs)
@classmethod
def _from_sequence(
cls,
scalars: Sequence[Optional[Period]],
dtype: Optional[PeriodDtype] = None,
copy: bool = False,
) -> ABCPeriodArray:
if dtype:
freq = dtype.freq
else:
freq = None
if isinstance(scalars, cls):
validate_dtype_freq(scalars.dtype, freq)
if copy:
scalars = scalars.copy()
return scalars
periods = np.asarray(scalars, dtype=object)
if copy:
periods = periods.copy()
freq = freq or libperiod.extract_freq(periods)
ordinals = libperiod.extract_ordinals(periods, freq)
return cls(ordinals, freq=freq)
@classmethod
def _from_sequence_of_strings(cls, strings, dtype=None, copy=False):
return cls._from_sequence(strings, dtype, copy)
@classmethod
def _from_datetime64(cls, data, freq, tz=None):
"""
Construct a PeriodArray from a datetime64 array
Parameters
----------
data : ndarray[datetime64[ns], datetime64[ns, tz]]
freq : str or Tick
tz : tzinfo, optional
Returns
-------
PeriodArray[freq]
"""
data, freq = dt64arr_to_periodarr(data, freq, tz)
return cls(data, freq=freq)
@classmethod
def _generate_range(cls, start, end, periods, freq, fields):
periods = dtl.validate_periods(periods)
if freq is not None:
freq = Period._maybe_convert_freq(freq)
field_count = len(fields)
if start is not None or end is not None:
if field_count > 0:
raise ValueError(
"Can either instantiate from fields or endpoints, but not both"
)
subarr, freq = _get_ordinal_range(start, end, periods, freq)
elif field_count > 0:
subarr, freq = _range_from_fields(freq=freq, **fields)
else:
raise ValueError("Not enough parameters to construct Period range")
return subarr, freq
# -----------------------------------------------------------------
# DatetimeLike Interface
def _unbox_scalar(self, value: Union[Period, NaTType]) -> int:
if value is NaT:
return value.value
elif isinstance(value, self._scalar_type):
if not isna(value):
self._check_compatible_with(value)
return value.ordinal
else:
raise ValueError(f"'value' should be a Period. Got '{value}' instead.")
def _scalar_from_string(self, value: str) -> Period:
return Period(value, freq=self.freq)
def _check_compatible_with(self, other, setitem: bool = False):
if other is NaT:
return
if self.freqstr != other.freqstr:
raise raise_on_incompatible(self, other)
# --------------------------------------------------------------------
# Data / Attributes
@cache_readonly
def dtype(self):
return self._dtype
# error: Read-only property cannot override read-write property [misc]
@property # type: ignore
def freq(self):
"""
Return the frequency object for this PeriodArray.
"""
return self.dtype.freq
def __array__(self, dtype=None):
# overriding DatetimelikeArray
return np.array(list(self), dtype=object)
# --------------------------------------------------------------------
# Vectorized analogues of Period properties
year = _field_accessor(
"year",
0,
"""
The year of the period.
""",
)
month = _field_accessor(
"month",
3,
"""
The month as January=1, December=12.
""",
)
day = _field_accessor(
"day",
4,
"""
The days of the period.
""",
)
hour = _field_accessor(
"hour",
5,
"""
The hour of the period.
""",
)
minute = _field_accessor(
"minute",
6,
"""
The minute of the period.
""",
)
second = _field_accessor(
"second",
7,
"""
The second of the period.
""",
)
weekofyear = _field_accessor(
"week",
8,
"""
The week ordinal of the year.
""",
)
week = weekofyear
dayofweek = _field_accessor(
"dayofweek",
10,
"""
The day of the week with Monday=0, Sunday=6.
""",
)
weekday = dayofweek
dayofyear = day_of_year = _field_accessor(
"dayofyear",
9,
"""
The ordinal day of the year.
""",
)
quarter = _field_accessor(
"quarter",
2,
"""
The quarter of the date.
""",
)
qyear = _field_accessor("qyear", 1)
days_in_month = _field_accessor(
"days_in_month",
11,
"""
The number of days in the month.
""",
)
daysinmonth = days_in_month
@property
def is_leap_year(self):
"""
Logical indicating if the date belongs to a leap year.
"""
return isleapyear_arr(np.asarray(self.year))
@property
def start_time(self):
return self.to_timestamp(how="start")
@property
def end_time(self):
return self.to_timestamp(how="end")
def to_timestamp(self, freq=None, how="start"):
"""
Cast to DatetimeArray/Index.
Parameters
----------
freq : str or DateOffset, optional
Target frequency. The default is 'D' for week or longer,
'S' otherwise.
how : {'s', 'e', 'start', 'end'}
Whether to use the start or end of the time period being converted.
Returns
-------
DatetimeArray/Index
"""
from pandas.core.arrays import DatetimeArray
how = libperiod._validate_end_alias(how)
end = how == "E"
if end:
if freq == "B":
# roll forward to ensure we land on B date
adjust = Timedelta(1, "D") - Timedelta(1, "ns")
return self.to_timestamp(how="start") + adjust
else:
adjust = Timedelta(1, "ns")
return (self + self.freq).to_timestamp(how="start") - adjust
if freq is None:
base, mult = libfrequencies.get_freq_code(self.freq)
freq = libfrequencies.get_to_timestamp_base(base)
else:
freq = Period._maybe_convert_freq(freq)
base, mult = libfrequencies.get_freq_code(freq)
new_data = self.asfreq(freq, how=how)
new_data = libperiod.periodarr_to_dt64arr(new_data.asi8, base)
return DatetimeArray._from_sequence(new_data, freq="infer")
# --------------------------------------------------------------------
# Array-like / EA-Interface Methods
@Appender(dtl.DatetimeLikeArrayMixin._validate_fill_value.__doc__)
def _validate_fill_value(self, fill_value):
if isna(fill_value):
fill_value = iNaT
elif isinstance(fill_value, Period):
self._check_compatible_with(fill_value)
fill_value = fill_value.ordinal
else:
raise ValueError(f"'fill_value' should be a Period. Got '{fill_value}'.")
return fill_value
def _values_for_argsort(self):
return self._data
# --------------------------------------------------------------------
def _time_shift(self, periods, freq=None):
"""
Shift each value by `periods`.
Note this is different from ExtensionArray.shift, which
shifts the *position* of each element, padding the end with
missing values.
Parameters
----------
periods : int
Number of periods to shift by.
freq : pandas.DateOffset, pandas.Timedelta, or str
Frequency increment to shift by.
"""
if freq is not None:
raise TypeError(
"`freq` argument is not supported for "
f"{type(self).__name__}._time_shift"
)
values = self.asi8 + periods * self.freq.n
if self._hasnans:
values[self._isnan] = iNaT
return type(self)(values, freq=self.freq)
@property
def _box_func(self):
return lambda x: Period._from_ordinal(ordinal=x, freq=self.freq)
def asfreq(self, freq=None, how="E"):
"""
Convert the Period Array/Index to the specified frequency `freq`.
Parameters
----------
freq : str
A frequency.
how : str {'E', 'S'}
Whether the elements should be aligned to the end
or start within pa period.
* 'E', 'END', or 'FINISH' for end,
* 'S', 'START', or 'BEGIN' for start.
January 31st ('END') vs. January 1st ('START') for example.
Returns
-------
Period Array/Index
Constructed with the new frequency.
Examples
--------
>>> pidx = pd.period_range('2010-01-01', '2015-01-01', freq='A')
>>> pidx
PeriodIndex(['2010', '2011', '2012', '2013', '2014', '2015'],
dtype='period[A-DEC]', freq='A-DEC')
>>> pidx.asfreq('M')
PeriodIndex(['2010-12', '2011-12', '2012-12', '2013-12', '2014-12',
'2015-12'], dtype='period[M]', freq='M')
>>> pidx.asfreq('M', how='S')
PeriodIndex(['2010-01', '2011-01', '2012-01', '2013-01', '2014-01',
'2015-01'], dtype='period[M]', freq='M')
"""
how = libperiod._validate_end_alias(how)
freq = Period._maybe_convert_freq(freq)
base1, mult1 = libfrequencies.get_freq_code(self.freq)
base2, mult2 = libfrequencies.get_freq_code(freq)
asi8 = self.asi8
# mult1 can't be negative or 0
end = how == "E"
if end:
ordinal = asi8 + mult1 - 1
else:
ordinal = asi8
new_data = period_asfreq_arr(ordinal, base1, base2, end)
if self._hasnans:
new_data[self._isnan] = iNaT
return type(self)(new_data, freq=freq)
# ------------------------------------------------------------------
# Rendering Methods
def _formatter(self, boxed=False):
if boxed:
return str
return "'{}'".format
def _format_native_types(self, na_rep="NaT", date_format=None, **kwargs):
"""
actually format my specific types
"""
values = self.astype(object)
if date_format:
formatter = lambda dt: dt.strftime(date_format)
else:
formatter = lambda dt: str(dt)
if self._hasnans:
mask = self._isnan
values[mask] = na_rep
imask = ~mask
values[imask] = np.array([formatter(dt) for dt in values[imask]])
else:
values = np.array([formatter(dt) for dt in values])
return values
# ------------------------------------------------------------------
def astype(self, dtype, copy=True):
# We handle Period[T] -> Period[U]
# Our parent handles everything else.
dtype = pandas_dtype(dtype)
if is_period_dtype(dtype):
return self.asfreq(dtype.freq)
return super().astype(dtype, copy=copy)
# ------------------------------------------------------------------
# Arithmetic Methods
_create_comparison_method = classmethod(_period_array_cmp)
def _sub_datelike(self, other):
assert other is not NaT
return NotImplemented
def _sub_period(self, other):
# If the operation is well-defined, we return an object-Index
# of DateOffsets. Null entries are filled with pd.NaT
self._check_compatible_with(other)
asi8 = self.asi8
new_data = asi8 - other.ordinal
new_data = np.array([self.freq * x for x in new_data])
if self._hasnans:
new_data[self._isnan] = NaT
return new_data
def _addsub_int_array(
self, other: np.ndarray, op: Callable[[Any, Any], Any],
) -> "PeriodArray":
"""
Add or subtract array of integers; equivalent to applying
`_time_shift` pointwise.
Parameters
----------
other : np.ndarray[integer-dtype]
op : {operator.add, operator.sub}
Returns
-------
result : PeriodArray
"""
assert op in [operator.add, operator.sub]
if op is operator.sub:
other = -other
res_values = algos.checked_add_with_arr(self.asi8, other, arr_mask=self._isnan)
res_values = res_values.view("i8")
res_values[self._isnan] = iNaT
return type(self)(res_values, freq=self.freq)
def _add_offset(self, other):
assert not isinstance(other, Tick)
base = libfrequencies.get_base_alias(other.rule_code)
if base != self.freq.rule_code:
raise raise_on_incompatible(self, other)
# Note: when calling parent class's _add_timedeltalike_scalar,
# it will call delta_to_nanoseconds(delta). Because delta here
# is an integer, delta_to_nanoseconds will return it unchanged.
result = super()._add_timedeltalike_scalar(other.n)
return type(self)(result, freq=self.freq)
def _add_timedeltalike_scalar(self, other):
"""
Parameters
----------
other : timedelta, Tick, np.timedelta64
Returns
-------
result : ndarray[int64]
"""
assert isinstance(self.freq, Tick) # checked by calling function
assert isinstance(other, (timedelta, np.timedelta64, Tick))
if notna(other):
# special handling for np.timedelta64("NaT"), avoid calling
# _check_timedeltalike_freq_compat as that would raise TypeError
other = self._check_timedeltalike_freq_compat(other)
# Note: when calling parent class's _add_timedeltalike_scalar,
# it will call delta_to_nanoseconds(delta). Because delta here
# is an integer, delta_to_nanoseconds will return it unchanged.
ordinals = super()._add_timedeltalike_scalar(other)
return ordinals
def _add_delta_tdi(self, other):
"""
Parameters
----------
other : TimedeltaArray or ndarray[timedelta64]
Returns
-------
result : ndarray[int64]
"""
assert isinstance(self.freq, Tick) # checked by calling function
if not np.all(isna(other)):
delta = self._check_timedeltalike_freq_compat(other)
else:
# all-NaT TimedeltaIndex is equivalent to a single scalar td64 NaT
return self + np.timedelta64("NaT")
return self._addsub_int_array(delta, operator.add).asi8
def _add_delta(self, other):
"""
Add a timedelta-like, Tick, or TimedeltaIndex-like object
to self, yielding a new PeriodArray
Parameters
----------
other : {timedelta, np.timedelta64, Tick,
TimedeltaIndex, ndarray[timedelta64]}
Returns
-------
result : PeriodArray
"""
if not isinstance(self.freq, Tick):
# We cannot add timedelta-like to non-tick PeriodArray
raise raise_on_incompatible(self, other)
new_ordinals = super()._add_delta(other)
return type(self)(new_ordinals, freq=self.freq)
def _check_timedeltalike_freq_compat(self, other):
"""
Arithmetic operations with timedelta-like scalars or array `other`
are only valid if `other` is an integer multiple of `self.freq`.
If the operation is valid, find that integer multiple. Otherwise,
raise because the operation is invalid.
Parameters
----------
other : timedelta, np.timedelta64, Tick,
ndarray[timedelta64], TimedeltaArray, TimedeltaIndex
Returns
-------
multiple : int or ndarray[int64]
Raises
------
IncompatibleFrequency
"""
assert isinstance(self.freq, Tick) # checked by calling function
own_offset = frequencies.to_offset(self.freq.rule_code)
base_nanos = delta_to_nanoseconds(own_offset)
if isinstance(other, (timedelta, np.timedelta64, Tick)):
nanos = delta_to_nanoseconds(other)
elif isinstance(other, np.ndarray):
# numpy timedelta64 array; all entries must be compatible
assert other.dtype.kind == "m"
if other.dtype != _TD_DTYPE:
# i.e. non-nano unit
# TODO: disallow unit-less timedelta64
other = other.astype(_TD_DTYPE)
nanos = other.view("i8")
else:
# TimedeltaArray/Index
nanos = other.asi8
if np.all(nanos % base_nanos == 0):
# nanos being added is an integer multiple of the
# base-frequency to self.freq
delta = nanos // base_nanos
# delta is the integer (or integer-array) number of periods
# by which will be added to self.
return delta
raise raise_on_incompatible(self, other)
PeriodArray._add_comparison_ops()
def raise_on_incompatible(left, right):
"""
Helper function to render a consistent error message when raising
IncompatibleFrequency.
Parameters
----------
left : PeriodArray
right : None, DateOffset, Period, ndarray, or timedelta-like
Returns
------
IncompatibleFrequency
Exception to be raised by the caller.
"""
# GH#24283 error message format depends on whether right is scalar
if isinstance(right, np.ndarray) or right is None:
other_freq = None
elif isinstance(right, (ABCPeriodIndex, PeriodArray, Period, DateOffset)):
other_freq = right.freqstr
else:
other_freq = _delta_to_tick(Timedelta(right)).freqstr
msg = DIFFERENT_FREQ.format(
cls=type(left).__name__, own_freq=left.freqstr, other_freq=other_freq
)
return IncompatibleFrequency(msg)
# -------------------------------------------------------------------
# Constructor Helpers
def period_array(
data: Sequence[Optional[Period]],
freq: Optional[Union[str, Tick]] = None,
copy: bool = False,
) -> PeriodArray:
"""
Construct a new PeriodArray from a sequence of Period scalars.
Parameters
----------
data : Sequence of Period objects
A sequence of Period objects. These are required to all have
the same ``freq.`` Missing values can be indicated by ``None``
or ``pandas.NaT``.
freq : str, Tick, or Offset
The frequency of every element of the array. This can be specified
to avoid inferring the `freq` from `data`.
copy : bool, default False
Whether to ensure a copy of the data is made.
Returns
-------
PeriodArray
See Also
--------
PeriodArray
pandas.PeriodIndex
Examples
--------
>>> period_array([pd.Period('2017', freq='A'),
... pd.Period('2018', freq='A')])
<PeriodArray>
['2017', '2018']
Length: 2, dtype: period[A-DEC]
>>> period_array([pd.Period('2017', freq='A'),
... pd.Period('2018', freq='A'),
... pd.NaT])
<PeriodArray>
['2017', '2018', 'NaT']
Length: 3, dtype: period[A-DEC]
Integers that look like years are handled
>>> period_array([2000, 2001, 2002], freq='D')
['2000-01-01', '2001-01-01', '2002-01-01']
Length: 3, dtype: period[D]
Datetime-like strings may also be passed
>>> period_array(['2000-Q1', '2000-Q2', '2000-Q3', '2000-Q4'], freq='Q')
<PeriodArray>
['2000Q1', '2000Q2', '2000Q3', '2000Q4']
Length: 4, dtype: period[Q-DEC]
"""
if is_datetime64_dtype(data):
return PeriodArray._from_datetime64(data, freq)
if isinstance(data, (ABCPeriodIndex, ABCSeries, PeriodArray)):
return PeriodArray(data, freq)
# other iterable of some kind
if not isinstance(data, (np.ndarray, list, tuple)):
data = list(data)
data = np.asarray(data)
dtype: Optional[PeriodDtype]
if freq:
dtype = PeriodDtype(freq)
else:
dtype = None
if is_float_dtype(data) and len(data) > 0:
raise TypeError("PeriodIndex does not allow floating point in construction")
data = ensure_object(data)
return PeriodArray._from_sequence(data, dtype=dtype)
def validate_dtype_freq(dtype, freq):
"""
If both a dtype and a freq are available, ensure they match. If only
dtype is available, extract the implied freq.
Parameters
----------
dtype : dtype
freq : DateOffset or None
Returns
-------
freq : DateOffset
Raises
------
ValueError : non-period dtype
IncompatibleFrequency : mismatch between dtype and freq
"""
if freq is not None:
freq = frequencies.to_offset(freq)
if dtype is not None:
dtype = pandas_dtype(dtype)
if not is_period_dtype(dtype):
raise ValueError("dtype must be PeriodDtype")
if freq is None:
freq = dtype.freq
elif freq != dtype.freq:
raise IncompatibleFrequency("specified freq and dtype are different")
return freq
def dt64arr_to_periodarr(data, freq, tz=None):
"""
Convert an datetime-like array to values Period ordinals.
Parameters
----------
data : Union[Series[datetime64[ns]], DatetimeIndex, ndarray[datetime64ns]]
freq : Optional[Union[str, Tick]]
Must match the `freq` on the `data` if `data` is a DatetimeIndex
or Series.
tz : Optional[tzinfo]
Returns
-------
ordinals : ndarray[int]
freq : Tick
The frequency extracted from the Series or DatetimeIndex if that's
used.
"""
if data.dtype != np.dtype("M8[ns]"):
raise ValueError(f"Wrong dtype: {data.dtype}")
if freq is None:
if isinstance(data, ABCIndexClass):
data, freq = data._values, data.freq
elif isinstance(data, ABCSeries):
data, freq = data._values, data.dt.freq
freq = Period._maybe_convert_freq(freq)
if isinstance(data, (ABCIndexClass, ABCSeries)):
data = data._values
base, mult = libfrequencies.get_freq_code(freq)
return libperiod.dt64arr_to_periodarr(data.view("i8"), base, tz), freq
def _get_ordinal_range(start, end, periods, freq, mult=1):
if com.count_not_none(start, end, periods) != 2:
raise ValueError(
"Of the three parameters: start, end, and periods, "
"exactly two must be specified"
)
if freq is not None:
_, mult = libfrequencies.get_freq_code(freq)
if start is not None:
start = Period(start, freq)
if end is not None:
end = Period(end, freq)
is_start_per = isinstance(start, Period)
is_end_per = isinstance(end, Period)
if is_start_per and is_end_per and start.freq != end.freq:
raise ValueError("start and end must have same freq")
if start is NaT or end is NaT:
raise ValueError("start and end must not be NaT")
if freq is None:
if is_start_per:
freq = start.freq
elif is_end_per:
freq = end.freq
else: # pragma: no cover
raise ValueError("Could not infer freq from start/end")
if periods is not None:
periods = periods * mult
if start is None:
data = np.arange(
end.ordinal - periods + mult, end.ordinal + 1, mult, dtype=np.int64
)
else:
data = np.arange(
start.ordinal, start.ordinal + periods, mult, dtype=np.int64
)
else:
data = np.arange(start.ordinal, end.ordinal + 1, mult, dtype=np.int64)
return data, freq
def _range_from_fields(
year=None,
month=None,
quarter=None,
day=None,
hour=None,
minute=None,
second=None,
freq=None,
):
if hour is None:
hour = 0
if minute is None:
minute = 0
if second is None:
second = 0
if day is None:
day = 1
ordinals = []
if quarter is not None:
if freq is None:
freq = "Q"
base = libfrequencies.FreqGroup.FR_QTR
else:
base, mult = libfrequencies.get_freq_code(freq)
if base != libfrequencies.FreqGroup.FR_QTR:
raise AssertionError("base must equal FR_QTR")
year, quarter = _make_field_arrays(year, quarter)
for y, q in zip(year, quarter):
y, m = libperiod.quarter_to_myear(y, q, freq)
val = libperiod.period_ordinal(y, m, 1, 1, 1, 1, 0, 0, base)
ordinals.append(val)
else:
base, mult = libfrequencies.get_freq_code(freq)
arrays = _make_field_arrays(year, month, day, hour, minute, second)
for y, mth, d, h, mn, s in zip(*arrays):
ordinals.append(libperiod.period_ordinal(y, mth, d, h, mn, s, 0, 0, base))
return np.array(ordinals, dtype=np.int64), freq
def _make_field_arrays(*fields):
length = None
for x in fields:
if isinstance(x, (list, np.ndarray, ABCSeries)):
if length is not None and len(x) != length:
raise ValueError("Mismatched Period array lengths")
elif length is None:
length = len(x)
arrays = [
np.asarray(x)
if isinstance(x, (np.ndarray, list, ABCSeries))
else np.repeat(x, length)
for x in fields
]
return arrays
| BugsInPy/BugsInPy/temp/projects/pandas/bug-95-fixed/pandas/pandas/core/arrays/period.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-95-buggy/pandas/pandas/core/arrays/period.py |
pandas-bug-33 | import numbers
from typing import TYPE_CHECKING, Tuple, Type, Union
import warnings
import numpy as np
from pandas._libs import lib, missing as libmissing
from pandas._typing import ArrayLike
from pandas.compat import set_function_name
from pandas.util._decorators import cache_readonly
from pandas.core.dtypes.base import ExtensionDtype
from pandas.core.dtypes.cast import astype_nansafe
from pandas.core.dtypes.common import (
is_bool_dtype,
is_datetime64_dtype,
is_float,
is_float_dtype,
is_integer,
is_integer_dtype,
is_list_like,
is_object_dtype,
is_scalar,
pandas_dtype,
)
from pandas.core.dtypes.dtypes import register_extension_dtype
from pandas.core.dtypes.missing import isna
from pandas.core import nanops, ops
from pandas.core.array_algos import masked_reductions
import pandas.core.common as com
from pandas.core.indexers import check_array_indexer
from pandas.core.ops import invalid_comparison
from pandas.core.ops.common import unpack_zerodim_and_defer
from pandas.core.tools.numeric import to_numeric
from .masked import BaseMaskedArray
if TYPE_CHECKING:
import pyarrow # noqa: F401
class _IntegerDtype(ExtensionDtype):
"""
An ExtensionDtype to hold a single size & kind of integer dtype.
These specific implementations are subclasses of the non-public
_IntegerDtype. For example we have Int8Dtype to represent signed int 8s.
The attributes name & type are set when these subclasses are created.
"""
name: str
base = None
type: Type
na_value = libmissing.NA
def __repr__(self) -> str:
sign = "U" if self.is_unsigned_integer else ""
return f"{sign}Int{8 * self.itemsize}Dtype()"
@cache_readonly
def is_signed_integer(self) -> bool:
return self.kind == "i"
@cache_readonly
def is_unsigned_integer(self) -> bool:
return self.kind == "u"
@property
def _is_numeric(self) -> bool:
return True
@cache_readonly
def numpy_dtype(self) -> np.dtype:
""" Return an instance of our numpy dtype """
return np.dtype(self.type)
@cache_readonly
def kind(self) -> str:
return self.numpy_dtype.kind
@cache_readonly
def itemsize(self) -> int:
""" Return the number of bytes in this dtype """
return self.numpy_dtype.itemsize
@classmethod
def construct_array_type(cls) -> Type["IntegerArray"]:
"""
Return the array type associated with this dtype.
Returns
-------
type
"""
return IntegerArray
def __from_arrow__(
self, array: Union["pyarrow.Array", "pyarrow.ChunkedArray"]
) -> "IntegerArray":
"""
Construct IntegerArray from pyarrow Array/ChunkedArray.
"""
import pyarrow # noqa: F811
from pandas.core.arrays._arrow_utils import pyarrow_array_to_numpy_and_mask
pyarrow_type = pyarrow.from_numpy_dtype(self.type)
if not array.type.equals(pyarrow_type):
array = array.cast(pyarrow_type)
if isinstance(array, pyarrow.Array):
chunks = [array]
else:
# pyarrow.ChunkedArray
chunks = array.chunks
results = []
for arr in chunks:
data, mask = pyarrow_array_to_numpy_and_mask(arr, dtype=self.type)
int_arr = IntegerArray(data.copy(), ~mask, copy=False)
results.append(int_arr)
return IntegerArray._concat_same_type(results)
def integer_array(values, dtype=None, copy: bool = False,) -> "IntegerArray":
"""
Infer and return an integer array of the values.
Parameters
----------
values : 1D list-like
dtype : dtype, optional
dtype to coerce
copy : bool, default False
Returns
-------
IntegerArray
Raises
------
TypeError if incompatible types
"""
values, mask = coerce_to_array(values, dtype=dtype, copy=copy)
return IntegerArray(values, mask)
def safe_cast(values, dtype, copy: bool):
"""
Safely cast the values to the dtype if they
are equivalent, meaning floats must be equivalent to the
ints.
"""
try:
return values.astype(dtype, casting="safe", copy=copy)
except TypeError as err:
casted = values.astype(dtype, copy=copy)
if (casted == values).all():
return casted
raise TypeError(
f"cannot safely cast non-equivalent {values.dtype} to {np.dtype(dtype)}"
) from err
def coerce_to_array(
values, dtype, mask=None, copy: bool = False,
) -> Tuple[np.ndarray, np.ndarray]:
"""
Coerce the input values array to numpy arrays with a mask
Parameters
----------
values : 1D list-like
dtype : integer dtype
mask : bool 1D array, optional
copy : bool, default False
if True, copy the input
Returns
-------
tuple of (values, mask)
"""
# if values is integer numpy array, preserve it's dtype
if dtype is None and hasattr(values, "dtype"):
if is_integer_dtype(values.dtype):
dtype = values.dtype
if dtype is not None:
if isinstance(dtype, str) and (
dtype.startswith("Int") or dtype.startswith("UInt")
):
# Avoid DeprecationWarning from NumPy about np.dtype("Int64")
# https://github.com/numpy/numpy/pull/7476
dtype = dtype.lower()
if not issubclass(type(dtype), _IntegerDtype):
try:
dtype = _dtypes[str(np.dtype(dtype))]
except KeyError as err:
raise ValueError(f"invalid dtype specified {dtype}") from err
if isinstance(values, IntegerArray):
values, mask = values._data, values._mask
if dtype is not None:
values = values.astype(dtype.numpy_dtype, copy=False)
if copy:
values = values.copy()
mask = mask.copy()
return values, mask
values = np.array(values, copy=copy)
if is_object_dtype(values):
inferred_type = lib.infer_dtype(values, skipna=True)
if inferred_type == "empty":
values = np.empty(len(values))
values.fill(np.nan)
elif inferred_type not in [
"floating",
"integer",
"mixed-integer",
"integer-na",
"mixed-integer-float",
]:
raise TypeError(f"{values.dtype} cannot be converted to an IntegerDtype")
elif is_bool_dtype(values) and is_integer_dtype(dtype):
values = np.array(values, dtype=int, copy=copy)
elif not (is_integer_dtype(values) or is_float_dtype(values)):
raise TypeError(f"{values.dtype} cannot be converted to an IntegerDtype")
if mask is None:
mask = isna(values)
else:
assert len(mask) == len(values)
if not values.ndim == 1:
raise TypeError("values must be a 1D list-like")
if not mask.ndim == 1:
raise TypeError("mask must be a 1D list-like")
# infer dtype if needed
if dtype is None:
dtype = np.dtype("int64")
else:
dtype = dtype.type
# if we are float, let's make sure that we can
# safely cast
# we copy as need to coerce here
if mask.any():
values = values.copy()
values[mask] = 1
values = safe_cast(values, dtype, copy=False)
else:
values = safe_cast(values, dtype, copy=False)
return values, mask
class IntegerArray(BaseMaskedArray):
"""
Array of integer (optional missing) values.
.. versionadded:: 0.24.0
.. versionchanged:: 1.0.0
Now uses :attr:`pandas.NA` as the missing value rather
than :attr:`numpy.nan`.
.. warning::
IntegerArray is currently experimental, and its API or internal
implementation may change without warning.
We represent an IntegerArray with 2 numpy arrays:
- data: contains a numpy integer array of the appropriate dtype
- mask: a boolean array holding a mask on the data, True is missing
To construct an IntegerArray from generic array-like input, use
:func:`pandas.array` with one of the integer dtypes (see examples).
See :ref:`integer_na` for more.
Parameters
----------
values : numpy.ndarray
A 1-d integer-dtype array.
mask : numpy.ndarray
A 1-d boolean-dtype array indicating missing values.
copy : bool, default False
Whether to copy the `values` and `mask`.
Attributes
----------
None
Methods
-------
None
Returns
-------
IntegerArray
Examples
--------
Create an IntegerArray with :func:`pandas.array`.
>>> int_array = pd.array([1, None, 3], dtype=pd.Int32Dtype())
>>> int_array
<IntegerArray>
[1, <NA>, 3]
Length: 3, dtype: Int32
String aliases for the dtypes are also available. They are capitalized.
>>> pd.array([1, None, 3], dtype='Int32')
<IntegerArray>
[1, <NA>, 3]
Length: 3, dtype: Int32
>>> pd.array([1, None, 3], dtype='UInt16')
<IntegerArray>
[1, <NA>, 3]
Length: 3, dtype: UInt16
"""
# The value used to fill '_data' to avoid upcasting
_internal_fill_value = 1
@cache_readonly
def dtype(self) -> _IntegerDtype:
return _dtypes[str(self._data.dtype)]
def __init__(self, values: np.ndarray, mask: np.ndarray, copy: bool = False):
if not (isinstance(values, np.ndarray) and is_integer_dtype(values.dtype)):
raise TypeError(
"values should be integer numpy array. Use "
"the 'integer_array' function instead"
)
if not (isinstance(mask, np.ndarray) and is_bool_dtype(mask.dtype)):
raise TypeError(
"mask should be boolean numpy array. Use "
"the 'integer_array' function instead"
)
super().__init__(values, mask, copy=copy)
@classmethod
def _from_sequence(cls, scalars, dtype=None, copy: bool = False) -> "IntegerArray":
return integer_array(scalars, dtype=dtype, copy=copy)
@classmethod
def _from_sequence_of_strings(
cls, strings, dtype=None, copy: bool = False
) -> "IntegerArray":
scalars = to_numeric(strings, errors="raise")
return cls._from_sequence(scalars, dtype, copy)
@classmethod
def _from_factorized(cls, values, original) -> "IntegerArray":
return integer_array(values, dtype=original.dtype)
_HANDLED_TYPES = (np.ndarray, numbers.Number)
def __array_ufunc__(self, ufunc, method: str, *inputs, **kwargs):
# For IntegerArray inputs, we apply the ufunc to ._data
# and mask the result.
if method == "reduce":
# Not clear how to handle missing values in reductions. Raise.
raise NotImplementedError("The 'reduce' method is not supported.")
out = kwargs.get("out", ())
for x in inputs + out:
if not isinstance(x, self._HANDLED_TYPES + (IntegerArray,)):
return NotImplemented
# for binary ops, use our custom dunder methods
result = ops.maybe_dispatch_ufunc_to_dunder_op(
self, ufunc, method, *inputs, **kwargs
)
if result is not NotImplemented:
return result
mask = np.zeros(len(self), dtype=bool)
inputs2 = []
for x in inputs:
if isinstance(x, IntegerArray):
mask |= x._mask
inputs2.append(x._data)
else:
inputs2.append(x)
def reconstruct(x):
# we don't worry about scalar `x` here, since we
# raise for reduce up above.
if is_integer_dtype(x.dtype):
m = mask.copy()
return IntegerArray(x, m)
else:
x[mask] = np.nan
return x
result = getattr(ufunc, method)(*inputs2, **kwargs)
if isinstance(result, tuple):
tuple(reconstruct(x) for x in result)
else:
return reconstruct(result)
def __setitem__(self, key, value) -> None:
_is_scalar = is_scalar(value)
if _is_scalar:
value = [value]
value, mask = coerce_to_array(value, dtype=self.dtype)
if _is_scalar:
value = value[0]
mask = mask[0]
key = check_array_indexer(self, key)
self._data[key] = value
self._mask[key] = mask
def astype(self, dtype, copy: bool = True) -> ArrayLike:
"""
Cast to a NumPy array or ExtensionArray with 'dtype'.
Parameters
----------
dtype : str or dtype
Typecode or data-type to which the array is cast.
copy : bool, default True
Whether to copy the data, even if not necessary. If False,
a copy is made only if the old dtype does not match the
new dtype.
Returns
-------
ndarray or ExtensionArray
NumPy ndarray, BooleanArray or IntegerArray with 'dtype' for its dtype.
Raises
------
TypeError
if incompatible type with an IntegerDtype, equivalent of same_kind
casting
"""
from pandas.core.arrays.boolean import BooleanArray, BooleanDtype
dtype = pandas_dtype(dtype)
# if we are astyping to an existing IntegerDtype we can fastpath
if isinstance(dtype, _IntegerDtype):
result = self._data.astype(dtype.numpy_dtype, copy=False)
return type(self)(result, mask=self._mask, copy=False)
elif isinstance(dtype, BooleanDtype):
result = self._data.astype("bool", copy=False)
return BooleanArray(result, mask=self._mask, copy=False)
# coerce
if is_float_dtype(dtype):
# In astype, we consider dtype=float to also mean na_value=np.nan
kwargs = dict(na_value=np.nan)
elif is_datetime64_dtype(dtype):
kwargs = dict(na_value=np.datetime64("NaT"))
else:
kwargs = {}
data = self.to_numpy(dtype=dtype, **kwargs)
return astype_nansafe(data, dtype, copy=False)
def _values_for_factorize(self) -> Tuple[np.ndarray, float]:
# TODO: https://github.com/pandas-dev/pandas/issues/30037
# use masked algorithms, rather than object-dtype / np.nan.
return self.to_numpy(na_value=np.nan), np.nan
def _values_for_argsort(self) -> np.ndarray:
"""
Return values for sorting.
Returns
-------
ndarray
The transformed values should maintain the ordering between values
within the array.
See Also
--------
ExtensionArray.argsort
"""
data = self._data.copy()
data[self._mask] = data.min() - 1
return data
@classmethod
def _create_comparison_method(cls, op):
op_name = op.__name__
@unpack_zerodim_and_defer(op.__name__)
def cmp_method(self, other):
from pandas.arrays import BooleanArray
mask = None
if isinstance(other, (BooleanArray, IntegerArray)):
other, mask = other._data, other._mask
elif is_list_like(other):
other = np.asarray(other)
if other.ndim > 1:
raise NotImplementedError(
"can only perform ops with 1-d structures"
)
if len(self) != len(other):
raise ValueError("Lengths must match to compare")
if other is libmissing.NA:
# numpy does not handle pd.NA well as "other" scalar (it returns
# a scalar False instead of an array)
# This may be fixed by NA.__array_ufunc__. Revisit this check
# once that's implemented.
result = np.zeros(self._data.shape, dtype="bool")
mask = np.ones(self._data.shape, dtype="bool")
else:
with warnings.catch_warnings():
# numpy may show a FutureWarning:
# elementwise comparison failed; returning scalar instead,
# but in the future will perform elementwise comparison
# before returning NotImplemented. We fall back to the correct
# behavior today, so that should be fine to ignore.
warnings.filterwarnings("ignore", "elementwise", FutureWarning)
with np.errstate(all="ignore"):
method = getattr(self._data, f"__{op_name}__")
result = method(other)
if result is NotImplemented:
result = invalid_comparison(self._data, other, op)
# nans propagate
if mask is None:
mask = self._mask.copy()
else:
mask = self._mask | mask
return BooleanArray(result, mask)
name = f"__{op.__name__}__"
return set_function_name(cmp_method, name, cls)
def _reduce(self, name: str, skipna: bool = True, **kwargs):
data = self._data
mask = self._mask
if name == "sum":
return masked_reductions.sum(data, mask, skipna=skipna, **kwargs)
# coerce to a nan-aware float if needed
# (we explicitly use NaN within reductions)
if self._hasna:
data = self.to_numpy("float64", na_value=np.nan)
op = getattr(nanops, "nan" + name)
result = op(data, axis=0, skipna=skipna, mask=mask, **kwargs)
if np.isnan(result):
return libmissing.NA
# if we have a boolean op, don't coerce
if name in ["any", "all"]:
pass
# if we have a preservable numeric op,
# provide coercion back to an integer type if possible
elif name in ["min", "max", "prod"]:
# GH#31409 more performant than casting-then-checking
result = com.cast_scalar_indexer(result)
return result
def _maybe_mask_result(self, result, mask, other, op_name: str):
"""
Parameters
----------
result : array-like
mask : array-like bool
other : scalar or array-like
op_name : str
"""
# if we have a float operand we are by-definition
# a float result
# or our op is a divide
if (is_float_dtype(other) or is_float(other)) or (
op_name in ["rtruediv", "truediv"]
):
result[mask] = np.nan
return result
return type(self)(result, mask, copy=False)
@classmethod
def _create_arithmetic_method(cls, op):
op_name = op.__name__
@unpack_zerodim_and_defer(op.__name__)
def integer_arithmetic_method(self, other):
omask = None
if getattr(other, "ndim", 0) > 1:
raise NotImplementedError("can only perform ops with 1-d structures")
if isinstance(other, IntegerArray):
other, omask = other._data, other._mask
elif is_list_like(other):
other = np.asarray(other)
if other.ndim > 1:
raise NotImplementedError(
"can only perform ops with 1-d structures"
)
if len(self) != len(other):
raise ValueError("Lengths must match")
if not (is_float_dtype(other) or is_integer_dtype(other)):
raise TypeError("can only perform ops with numeric values")
else:
if not (is_float(other) or is_integer(other) or other is libmissing.NA):
raise TypeError("can only perform ops with numeric values")
if omask is None:
mask = self._mask.copy()
if other is libmissing.NA:
mask |= True
else:
mask = self._mask | omask
if op_name == "pow":
# 1 ** x is 1.
mask = np.where((self._data == 1) & ~self._mask, False, mask)
# x ** 0 is 1.
if omask is not None:
mask = np.where((other == 0) & ~omask, False, mask)
elif other is not libmissing.NA:
mask = np.where(other == 0, False, mask)
elif op_name == "rpow":
# 1 ** x is 1.
if omask is not None:
mask = np.where((other == 1) & ~omask, False, mask)
elif other is not libmissing.NA:
mask = np.where(other == 1, False, mask)
# x ** 0 is 1.
mask = np.where((self._data == 0) & ~self._mask, False, mask)
if other is libmissing.NA:
result = np.ones_like(self._data)
else:
with np.errstate(all="ignore"):
result = op(self._data, other)
# divmod returns a tuple
if op_name == "divmod":
div, mod = result
return (
self._maybe_mask_result(div, mask, other, "floordiv"),
self._maybe_mask_result(mod, mask, other, "mod"),
)
return self._maybe_mask_result(result, mask, other, op_name)
name = f"__{op.__name__}__"
return set_function_name(integer_arithmetic_method, name, cls)
IntegerArray._add_arithmetic_ops()
IntegerArray._add_comparison_ops()
_dtype_docstring = """
An ExtensionDtype for {dtype} integer data.
.. versionchanged:: 1.0.0
Now uses :attr:`pandas.NA` as its missing value,
rather than :attr:`numpy.nan`.
Attributes
----------
None
Methods
-------
None
"""
# create the Dtype
@register_extension_dtype
class Int8Dtype(_IntegerDtype):
type = np.int8
name = "Int8"
__doc__ = _dtype_docstring.format(dtype="int8")
@register_extension_dtype
class Int16Dtype(_IntegerDtype):
type = np.int16
name = "Int16"
__doc__ = _dtype_docstring.format(dtype="int16")
@register_extension_dtype
class Int32Dtype(_IntegerDtype):
type = np.int32
name = "Int32"
__doc__ = _dtype_docstring.format(dtype="int32")
@register_extension_dtype
class Int64Dtype(_IntegerDtype):
type = np.int64
name = "Int64"
__doc__ = _dtype_docstring.format(dtype="int64")
@register_extension_dtype
class UInt8Dtype(_IntegerDtype):
type = np.uint8
name = "UInt8"
__doc__ = _dtype_docstring.format(dtype="uint8")
@register_extension_dtype
class UInt16Dtype(_IntegerDtype):
type = np.uint16
name = "UInt16"
__doc__ = _dtype_docstring.format(dtype="uint16")
@register_extension_dtype
class UInt32Dtype(_IntegerDtype):
type = np.uint32
name = "UInt32"
__doc__ = _dtype_docstring.format(dtype="uint32")
@register_extension_dtype
class UInt64Dtype(_IntegerDtype):
type = np.uint64
name = "UInt64"
__doc__ = _dtype_docstring.format(dtype="uint64")
_dtypes = {
"int8": Int8Dtype(),
"int16": Int16Dtype(),
"int32": Int32Dtype(),
"int64": Int64Dtype(),
"uint8": UInt8Dtype(),
"uint16": UInt16Dtype(),
"uint32": UInt32Dtype(),
"uint64": UInt64Dtype(),
}
import numbers
from typing import TYPE_CHECKING, Tuple, Type, Union
import warnings
import numpy as np
from pandas._libs import lib, missing as libmissing
from pandas._typing import ArrayLike
from pandas.compat import set_function_name
from pandas.util._decorators import cache_readonly
from pandas.core.dtypes.base import ExtensionDtype
from pandas.core.dtypes.cast import astype_nansafe
from pandas.core.dtypes.common import (
is_bool_dtype,
is_datetime64_dtype,
is_float,
is_float_dtype,
is_integer,
is_integer_dtype,
is_list_like,
is_object_dtype,
is_scalar,
pandas_dtype,
)
from pandas.core.dtypes.dtypes import register_extension_dtype
from pandas.core.dtypes.missing import isna
from pandas.core import nanops, ops
from pandas.core.array_algos import masked_reductions
import pandas.core.common as com
from pandas.core.indexers import check_array_indexer
from pandas.core.ops import invalid_comparison
from pandas.core.ops.common import unpack_zerodim_and_defer
from pandas.core.tools.numeric import to_numeric
from .masked import BaseMaskedArray
if TYPE_CHECKING:
import pyarrow # noqa: F401
class _IntegerDtype(ExtensionDtype):
"""
An ExtensionDtype to hold a single size & kind of integer dtype.
These specific implementations are subclasses of the non-public
_IntegerDtype. For example we have Int8Dtype to represent signed int 8s.
The attributes name & type are set when these subclasses are created.
"""
name: str
base = None
type: Type
na_value = libmissing.NA
def __repr__(self) -> str:
sign = "U" if self.is_unsigned_integer else ""
return f"{sign}Int{8 * self.itemsize}Dtype()"
@cache_readonly
def is_signed_integer(self) -> bool:
return self.kind == "i"
@cache_readonly
def is_unsigned_integer(self) -> bool:
return self.kind == "u"
@property
def _is_numeric(self) -> bool:
return True
@cache_readonly
def numpy_dtype(self) -> np.dtype:
""" Return an instance of our numpy dtype """
return np.dtype(self.type)
@cache_readonly
def kind(self) -> str:
return self.numpy_dtype.kind
@cache_readonly
def itemsize(self) -> int:
""" Return the number of bytes in this dtype """
return self.numpy_dtype.itemsize
@classmethod
def construct_array_type(cls) -> Type["IntegerArray"]:
"""
Return the array type associated with this dtype.
Returns
-------
type
"""
return IntegerArray
def __from_arrow__(
self, array: Union["pyarrow.Array", "pyarrow.ChunkedArray"]
) -> "IntegerArray":
"""
Construct IntegerArray from pyarrow Array/ChunkedArray.
"""
import pyarrow # noqa: F811
from pandas.core.arrays._arrow_utils import pyarrow_array_to_numpy_and_mask
pyarrow_type = pyarrow.from_numpy_dtype(self.type)
if not array.type.equals(pyarrow_type):
array = array.cast(pyarrow_type)
if isinstance(array, pyarrow.Array):
chunks = [array]
else:
# pyarrow.ChunkedArray
chunks = array.chunks
results = []
for arr in chunks:
data, mask = pyarrow_array_to_numpy_and_mask(arr, dtype=self.type)
int_arr = IntegerArray(data.copy(), ~mask, copy=False)
results.append(int_arr)
return IntegerArray._concat_same_type(results)
def integer_array(values, dtype=None, copy: bool = False,) -> "IntegerArray":
"""
Infer and return an integer array of the values.
Parameters
----------
values : 1D list-like
dtype : dtype, optional
dtype to coerce
copy : bool, default False
Returns
-------
IntegerArray
Raises
------
TypeError if incompatible types
"""
values, mask = coerce_to_array(values, dtype=dtype, copy=copy)
return IntegerArray(values, mask)
def safe_cast(values, dtype, copy: bool):
"""
Safely cast the values to the dtype if they
are equivalent, meaning floats must be equivalent to the
ints.
"""
try:
return values.astype(dtype, casting="safe", copy=copy)
except TypeError as err:
casted = values.astype(dtype, copy=copy)
if (casted == values).all():
return casted
raise TypeError(
f"cannot safely cast non-equivalent {values.dtype} to {np.dtype(dtype)}"
) from err
def coerce_to_array(
values, dtype, mask=None, copy: bool = False,
) -> Tuple[np.ndarray, np.ndarray]:
"""
Coerce the input values array to numpy arrays with a mask
Parameters
----------
values : 1D list-like
dtype : integer dtype
mask : bool 1D array, optional
copy : bool, default False
if True, copy the input
Returns
-------
tuple of (values, mask)
"""
# if values is integer numpy array, preserve it's dtype
if dtype is None and hasattr(values, "dtype"):
if is_integer_dtype(values.dtype):
dtype = values.dtype
if dtype is not None:
if isinstance(dtype, str) and (
dtype.startswith("Int") or dtype.startswith("UInt")
):
# Avoid DeprecationWarning from NumPy about np.dtype("Int64")
# https://github.com/numpy/numpy/pull/7476
dtype = dtype.lower()
if not issubclass(type(dtype), _IntegerDtype):
try:
dtype = _dtypes[str(np.dtype(dtype))]
except KeyError as err:
raise ValueError(f"invalid dtype specified {dtype}") from err
if isinstance(values, IntegerArray):
values, mask = values._data, values._mask
if dtype is not None:
values = values.astype(dtype.numpy_dtype, copy=False)
if copy:
values = values.copy()
mask = mask.copy()
return values, mask
values = np.array(values, copy=copy)
if is_object_dtype(values):
inferred_type = lib.infer_dtype(values, skipna=True)
if inferred_type == "empty":
values = np.empty(len(values))
values.fill(np.nan)
elif inferred_type not in [
"floating",
"integer",
"mixed-integer",
"integer-na",
"mixed-integer-float",
]:
raise TypeError(f"{values.dtype} cannot be converted to an IntegerDtype")
elif is_bool_dtype(values) and is_integer_dtype(dtype):
values = np.array(values, dtype=int, copy=copy)
elif not (is_integer_dtype(values) or is_float_dtype(values)):
raise TypeError(f"{values.dtype} cannot be converted to an IntegerDtype")
if mask is None:
mask = isna(values)
else:
assert len(mask) == len(values)
if not values.ndim == 1:
raise TypeError("values must be a 1D list-like")
if not mask.ndim == 1:
raise TypeError("mask must be a 1D list-like")
# infer dtype if needed
if dtype is None:
dtype = np.dtype("int64")
else:
dtype = dtype.type
# if we are float, let's make sure that we can
# safely cast
# we copy as need to coerce here
if mask.any():
values = values.copy()
values[mask] = 1
values = safe_cast(values, dtype, copy=False)
else:
values = safe_cast(values, dtype, copy=False)
return values, mask
class IntegerArray(BaseMaskedArray):
"""
Array of integer (optional missing) values.
.. versionadded:: 0.24.0
.. versionchanged:: 1.0.0
Now uses :attr:`pandas.NA` as the missing value rather
than :attr:`numpy.nan`.
.. warning::
IntegerArray is currently experimental, and its API or internal
implementation may change without warning.
We represent an IntegerArray with 2 numpy arrays:
- data: contains a numpy integer array of the appropriate dtype
- mask: a boolean array holding a mask on the data, True is missing
To construct an IntegerArray from generic array-like input, use
:func:`pandas.array` with one of the integer dtypes (see examples).
See :ref:`integer_na` for more.
Parameters
----------
values : numpy.ndarray
A 1-d integer-dtype array.
mask : numpy.ndarray
A 1-d boolean-dtype array indicating missing values.
copy : bool, default False
Whether to copy the `values` and `mask`.
Attributes
----------
None
Methods
-------
None
Returns
-------
IntegerArray
Examples
--------
Create an IntegerArray with :func:`pandas.array`.
>>> int_array = pd.array([1, None, 3], dtype=pd.Int32Dtype())
>>> int_array
<IntegerArray>
[1, <NA>, 3]
Length: 3, dtype: Int32
String aliases for the dtypes are also available. They are capitalized.
>>> pd.array([1, None, 3], dtype='Int32')
<IntegerArray>
[1, <NA>, 3]
Length: 3, dtype: Int32
>>> pd.array([1, None, 3], dtype='UInt16')
<IntegerArray>
[1, <NA>, 3]
Length: 3, dtype: UInt16
"""
# The value used to fill '_data' to avoid upcasting
_internal_fill_value = 1
@cache_readonly
def dtype(self) -> _IntegerDtype:
return _dtypes[str(self._data.dtype)]
def __init__(self, values: np.ndarray, mask: np.ndarray, copy: bool = False):
if not (isinstance(values, np.ndarray) and is_integer_dtype(values.dtype)):
raise TypeError(
"values should be integer numpy array. Use "
"the 'integer_array' function instead"
)
if not (isinstance(mask, np.ndarray) and is_bool_dtype(mask.dtype)):
raise TypeError(
"mask should be boolean numpy array. Use "
"the 'integer_array' function instead"
)
super().__init__(values, mask, copy=copy)
@classmethod
def _from_sequence(cls, scalars, dtype=None, copy: bool = False) -> "IntegerArray":
return integer_array(scalars, dtype=dtype, copy=copy)
@classmethod
def _from_sequence_of_strings(
cls, strings, dtype=None, copy: bool = False
) -> "IntegerArray":
scalars = to_numeric(strings, errors="raise")
return cls._from_sequence(scalars, dtype, copy)
@classmethod
def _from_factorized(cls, values, original) -> "IntegerArray":
return integer_array(values, dtype=original.dtype)
_HANDLED_TYPES = (np.ndarray, numbers.Number)
def __array_ufunc__(self, ufunc, method: str, *inputs, **kwargs):
# For IntegerArray inputs, we apply the ufunc to ._data
# and mask the result.
if method == "reduce":
# Not clear how to handle missing values in reductions. Raise.
raise NotImplementedError("The 'reduce' method is not supported.")
out = kwargs.get("out", ())
for x in inputs + out:
if not isinstance(x, self._HANDLED_TYPES + (IntegerArray,)):
return NotImplemented
# for binary ops, use our custom dunder methods
result = ops.maybe_dispatch_ufunc_to_dunder_op(
self, ufunc, method, *inputs, **kwargs
)
if result is not NotImplemented:
return result
mask = np.zeros(len(self), dtype=bool)
inputs2 = []
for x in inputs:
if isinstance(x, IntegerArray):
mask |= x._mask
inputs2.append(x._data)
else:
inputs2.append(x)
def reconstruct(x):
# we don't worry about scalar `x` here, since we
# raise for reduce up above.
if is_integer_dtype(x.dtype):
m = mask.copy()
return IntegerArray(x, m)
else:
x[mask] = np.nan
return x
result = getattr(ufunc, method)(*inputs2, **kwargs)
if isinstance(result, tuple):
tuple(reconstruct(x) for x in result)
else:
return reconstruct(result)
def __setitem__(self, key, value) -> None:
_is_scalar = is_scalar(value)
if _is_scalar:
value = [value]
value, mask = coerce_to_array(value, dtype=self.dtype)
if _is_scalar:
value = value[0]
mask = mask[0]
key = check_array_indexer(self, key)
self._data[key] = value
self._mask[key] = mask
def astype(self, dtype, copy: bool = True) -> ArrayLike:
"""
Cast to a NumPy array or ExtensionArray with 'dtype'.
Parameters
----------
dtype : str or dtype
Typecode or data-type to which the array is cast.
copy : bool, default True
Whether to copy the data, even if not necessary. If False,
a copy is made only if the old dtype does not match the
new dtype.
Returns
-------
ndarray or ExtensionArray
NumPy ndarray, BooleanArray or IntegerArray with 'dtype' for its dtype.
Raises
------
TypeError
if incompatible type with an IntegerDtype, equivalent of same_kind
casting
"""
from pandas.core.arrays.boolean import BooleanArray, BooleanDtype
dtype = pandas_dtype(dtype)
# if we are astyping to an existing IntegerDtype we can fastpath
if isinstance(dtype, _IntegerDtype):
result = self._data.astype(dtype.numpy_dtype, copy=False)
return type(self)(result, mask=self._mask, copy=False)
elif isinstance(dtype, BooleanDtype):
result = self._data.astype("bool", copy=False)
return BooleanArray(result, mask=self._mask, copy=False)
# coerce
if is_float_dtype(dtype):
# In astype, we consider dtype=float to also mean na_value=np.nan
kwargs = dict(na_value=np.nan)
elif is_datetime64_dtype(dtype):
kwargs = dict(na_value=np.datetime64("NaT"))
else:
kwargs = {}
data = self.to_numpy(dtype=dtype, **kwargs)
return astype_nansafe(data, dtype, copy=False)
def _values_for_factorize(self) -> Tuple[np.ndarray, float]:
# TODO: https://github.com/pandas-dev/pandas/issues/30037
# use masked algorithms, rather than object-dtype / np.nan.
return self.to_numpy(na_value=np.nan), np.nan
def _values_for_argsort(self) -> np.ndarray:
"""
Return values for sorting.
Returns
-------
ndarray
The transformed values should maintain the ordering between values
within the array.
See Also
--------
ExtensionArray.argsort
"""
data = self._data.copy()
if self._mask.any():
data[self._mask] = data.min() - 1
return data
@classmethod
def _create_comparison_method(cls, op):
op_name = op.__name__
@unpack_zerodim_and_defer(op.__name__)
def cmp_method(self, other):
from pandas.arrays import BooleanArray
mask = None
if isinstance(other, (BooleanArray, IntegerArray)):
other, mask = other._data, other._mask
elif is_list_like(other):
other = np.asarray(other)
if other.ndim > 1:
raise NotImplementedError(
"can only perform ops with 1-d structures"
)
if len(self) != len(other):
raise ValueError("Lengths must match to compare")
if other is libmissing.NA:
# numpy does not handle pd.NA well as "other" scalar (it returns
# a scalar False instead of an array)
# This may be fixed by NA.__array_ufunc__. Revisit this check
# once that's implemented.
result = np.zeros(self._data.shape, dtype="bool")
mask = np.ones(self._data.shape, dtype="bool")
else:
with warnings.catch_warnings():
# numpy may show a FutureWarning:
# elementwise comparison failed; returning scalar instead,
# but in the future will perform elementwise comparison
# before returning NotImplemented. We fall back to the correct
# behavior today, so that should be fine to ignore.
warnings.filterwarnings("ignore", "elementwise", FutureWarning)
with np.errstate(all="ignore"):
method = getattr(self._data, f"__{op_name}__")
result = method(other)
if result is NotImplemented:
result = invalid_comparison(self._data, other, op)
# nans propagate
if mask is None:
mask = self._mask.copy()
else:
mask = self._mask | mask
return BooleanArray(result, mask)
name = f"__{op.__name__}__"
return set_function_name(cmp_method, name, cls)
def _reduce(self, name: str, skipna: bool = True, **kwargs):
data = self._data
mask = self._mask
if name == "sum":
return masked_reductions.sum(data, mask, skipna=skipna, **kwargs)
# coerce to a nan-aware float if needed
# (we explicitly use NaN within reductions)
if self._hasna:
data = self.to_numpy("float64", na_value=np.nan)
op = getattr(nanops, "nan" + name)
result = op(data, axis=0, skipna=skipna, mask=mask, **kwargs)
if np.isnan(result):
return libmissing.NA
# if we have a boolean op, don't coerce
if name in ["any", "all"]:
pass
# if we have a preservable numeric op,
# provide coercion back to an integer type if possible
elif name in ["min", "max", "prod"]:
# GH#31409 more performant than casting-then-checking
result = com.cast_scalar_indexer(result)
return result
def _maybe_mask_result(self, result, mask, other, op_name: str):
"""
Parameters
----------
result : array-like
mask : array-like bool
other : scalar or array-like
op_name : str
"""
# if we have a float operand we are by-definition
# a float result
# or our op is a divide
if (is_float_dtype(other) or is_float(other)) or (
op_name in ["rtruediv", "truediv"]
):
result[mask] = np.nan
return result
return type(self)(result, mask, copy=False)
@classmethod
def _create_arithmetic_method(cls, op):
op_name = op.__name__
@unpack_zerodim_and_defer(op.__name__)
def integer_arithmetic_method(self, other):
omask = None
if getattr(other, "ndim", 0) > 1:
raise NotImplementedError("can only perform ops with 1-d structures")
if isinstance(other, IntegerArray):
other, omask = other._data, other._mask
elif is_list_like(other):
other = np.asarray(other)
if other.ndim > 1:
raise NotImplementedError(
"can only perform ops with 1-d structures"
)
if len(self) != len(other):
raise ValueError("Lengths must match")
if not (is_float_dtype(other) or is_integer_dtype(other)):
raise TypeError("can only perform ops with numeric values")
else:
if not (is_float(other) or is_integer(other) or other is libmissing.NA):
raise TypeError("can only perform ops with numeric values")
if omask is None:
mask = self._mask.copy()
if other is libmissing.NA:
mask |= True
else:
mask = self._mask | omask
if op_name == "pow":
# 1 ** x is 1.
mask = np.where((self._data == 1) & ~self._mask, False, mask)
# x ** 0 is 1.
if omask is not None:
mask = np.where((other == 0) & ~omask, False, mask)
elif other is not libmissing.NA:
mask = np.where(other == 0, False, mask)
elif op_name == "rpow":
# 1 ** x is 1.
if omask is not None:
mask = np.where((other == 1) & ~omask, False, mask)
elif other is not libmissing.NA:
mask = np.where(other == 1, False, mask)
# x ** 0 is 1.
mask = np.where((self._data == 0) & ~self._mask, False, mask)
if other is libmissing.NA:
result = np.ones_like(self._data)
else:
with np.errstate(all="ignore"):
result = op(self._data, other)
# divmod returns a tuple
if op_name == "divmod":
div, mod = result
return (
self._maybe_mask_result(div, mask, other, "floordiv"),
self._maybe_mask_result(mod, mask, other, "mod"),
)
return self._maybe_mask_result(result, mask, other, op_name)
name = f"__{op.__name__}__"
return set_function_name(integer_arithmetic_method, name, cls)
IntegerArray._add_arithmetic_ops()
IntegerArray._add_comparison_ops()
_dtype_docstring = """
An ExtensionDtype for {dtype} integer data.
.. versionchanged:: 1.0.0
Now uses :attr:`pandas.NA` as its missing value,
rather than :attr:`numpy.nan`.
Attributes
----------
None
Methods
-------
None
"""
# create the Dtype
@register_extension_dtype
class Int8Dtype(_IntegerDtype):
type = np.int8
name = "Int8"
__doc__ = _dtype_docstring.format(dtype="int8")
@register_extension_dtype
class Int16Dtype(_IntegerDtype):
type = np.int16
name = "Int16"
__doc__ = _dtype_docstring.format(dtype="int16")
@register_extension_dtype
class Int32Dtype(_IntegerDtype):
type = np.int32
name = "Int32"
__doc__ = _dtype_docstring.format(dtype="int32")
@register_extension_dtype
class Int64Dtype(_IntegerDtype):
type = np.int64
name = "Int64"
__doc__ = _dtype_docstring.format(dtype="int64")
@register_extension_dtype
class UInt8Dtype(_IntegerDtype):
type = np.uint8
name = "UInt8"
__doc__ = _dtype_docstring.format(dtype="uint8")
@register_extension_dtype
class UInt16Dtype(_IntegerDtype):
type = np.uint16
name = "UInt16"
__doc__ = _dtype_docstring.format(dtype="uint16")
@register_extension_dtype
class UInt32Dtype(_IntegerDtype):
type = np.uint32
name = "UInt32"
__doc__ = _dtype_docstring.format(dtype="uint32")
@register_extension_dtype
class UInt64Dtype(_IntegerDtype):
type = np.uint64
name = "UInt64"
__doc__ = _dtype_docstring.format(dtype="uint64")
_dtypes = {
"int8": Int8Dtype(),
"int16": Int16Dtype(),
"int32": Int32Dtype(),
"int64": Int64Dtype(),
"uint8": UInt8Dtype(),
"uint16": UInt16Dtype(),
"uint32": UInt32Dtype(),
"uint64": UInt64Dtype(),
}
| BugsInPy/BugsInPy/temp/projects/pandas/bug-33-fixed/pandas/pandas/core/arrays/integer.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-33-buggy/pandas/pandas/core/arrays/integer.py |
pandas-bug-17 | from datetime import datetime, timedelta
import operator
from typing import Any, Sequence, Type, Union, cast
import warnings
import numpy as np
from pandas._libs import NaT, NaTType, Timestamp, algos, iNaT, lib
from pandas._libs.tslibs.c_timestamp import integer_op_not_supported
from pandas._libs.tslibs.period import DIFFERENT_FREQ, IncompatibleFrequency, Period
from pandas._libs.tslibs.timedeltas import Timedelta, delta_to_nanoseconds
from pandas._libs.tslibs.timestamps import RoundTo, round_nsint64
from pandas._typing import DatetimeLikeScalar
from pandas.compat import set_function_name
from pandas.compat.numpy import function as nv
from pandas.errors import AbstractMethodError, NullFrequencyError, PerformanceWarning
from pandas.util._decorators import Appender, Substitution
from pandas.util._validators import validate_fillna_kwargs
from pandas.core.dtypes.common import (
is_categorical_dtype,
is_datetime64_any_dtype,
is_datetime64_dtype,
is_datetime64tz_dtype,
is_datetime_or_timedelta_dtype,
is_dtype_equal,
is_float_dtype,
is_integer_dtype,
is_list_like,
is_object_dtype,
is_period_dtype,
is_string_dtype,
is_timedelta64_dtype,
is_unsigned_integer_dtype,
pandas_dtype,
)
from pandas.core.dtypes.generic import ABCSeries
from pandas.core.dtypes.inference import is_array_like
from pandas.core.dtypes.missing import is_valid_nat_for_dtype, isna
from pandas.core import missing, nanops, ops
from pandas.core.algorithms import checked_add_with_arr, unique1d, value_counts
from pandas.core.array_algos.transforms import shift
from pandas.core.arrays._mixins import _T, NDArrayBackedExtensionArray
from pandas.core.arrays.base import ExtensionArray, ExtensionOpsMixin
import pandas.core.common as com
from pandas.core.construction import array, extract_array
from pandas.core.indexers import check_array_indexer
from pandas.core.ops.common import unpack_zerodim_and_defer
from pandas.core.ops.invalid import invalid_comparison, make_invalid_op
from pandas.tseries import frequencies
from pandas.tseries.offsets import DateOffset, Tick
def _datetimelike_array_cmp(cls, op):
"""
Wrap comparison operations to convert Timestamp/Timedelta/Period-like to
boxed scalars/arrays.
"""
opname = f"__{op.__name__}__"
nat_result = opname == "__ne__"
class InvalidComparison(Exception):
pass
def _validate_comparison_value(self, other):
if isinstance(other, str):
try:
# GH#18435 strings get a pass from tzawareness compat
other = self._scalar_from_string(other)
except ValueError:
# failed to parse as Timestamp/Timedelta/Period
raise InvalidComparison(other)
if isinstance(other, self._recognized_scalars) or other is NaT:
other = self._scalar_type(other)
self._check_compatible_with(other)
elif not is_list_like(other):
raise InvalidComparison(other)
elif len(other) != len(self):
raise ValueError("Lengths must match")
else:
if isinstance(other, list):
# TODO: could use pd.Index to do inference?
other = np.array(other)
if not isinstance(other, (np.ndarray, type(self))):
raise InvalidComparison(other)
elif is_object_dtype(other.dtype):
pass
elif not type(self)._is_recognized_dtype(other.dtype):
raise InvalidComparison(other)
else:
# For PeriodDType this casting is unnecessary
# TODO: use Index to do inference?
other = type(self)._from_sequence(other)
self._check_compatible_with(other)
return other
@unpack_zerodim_and_defer(opname)
def wrapper(self, other):
try:
other = _validate_comparison_value(self, other)
except InvalidComparison:
return invalid_comparison(self, other, op)
dtype = getattr(other, "dtype", None)
if is_object_dtype(dtype):
# We have to use comp_method_OBJECT_ARRAY instead of numpy
# comparison otherwise it would fail to raise when
# comparing tz-aware and tz-naive
with np.errstate(all="ignore"):
result = ops.comp_method_OBJECT_ARRAY(op, self.astype(object), other)
return result
if isinstance(other, self._scalar_type) or other is NaT:
other_i8 = self._unbox_scalar(other)
else:
# Then type(other) == type(self)
other_i8 = other.asi8
result = op(self.asi8, other_i8)
o_mask = isna(other)
if self._hasnans | np.any(o_mask):
result[self._isnan | o_mask] = nat_result
return result
return set_function_name(wrapper, opname, cls)
class AttributesMixin:
_data: np.ndarray
@classmethod
def _simple_new(cls, values: np.ndarray, **kwargs):
raise AbstractMethodError(cls)
@property
def _scalar_type(self) -> Type[DatetimeLikeScalar]:
"""
The scalar associated with this datelike
* PeriodArray : Period
* DatetimeArray : Timestamp
* TimedeltaArray : Timedelta
"""
raise AbstractMethodError(self)
def _scalar_from_string(
self, value: str
) -> Union[Period, Timestamp, Timedelta, NaTType]:
"""
Construct a scalar type from a string.
Parameters
----------
value : str
Returns
-------
Period, Timestamp, or Timedelta, or NaT
Whatever the type of ``self._scalar_type`` is.
Notes
-----
This should call ``self._check_compatible_with`` before
unboxing the result.
"""
raise AbstractMethodError(self)
def _unbox_scalar(self, value: Union[Period, Timestamp, Timedelta, NaTType]) -> int:
"""
Unbox the integer value of a scalar `value`.
Parameters
----------
value : Union[Period, Timestamp, Timedelta]
Returns
-------
int
Examples
--------
>>> self._unbox_scalar(Timedelta("10s")) # doctest: +SKIP
10000000000
"""
raise AbstractMethodError(self)
def _check_compatible_with(
self, other: Union[Period, Timestamp, Timedelta, NaTType], setitem: bool = False
) -> None:
"""
Verify that `self` and `other` are compatible.
* DatetimeArray verifies that the timezones (if any) match
* PeriodArray verifies that the freq matches
* Timedelta has no verification
In each case, NaT is considered compatible.
Parameters
----------
other
setitem : bool, default False
For __setitem__ we may have stricter compatibility resrictions than
for comparisons.
Raises
------
Exception
"""
raise AbstractMethodError(self)
class DatelikeOps:
"""
Common ops for DatetimeIndex/PeriodIndex, but not TimedeltaIndex.
"""
@Substitution(
URL="https://docs.python.org/3/library/datetime.html"
"#strftime-and-strptime-behavior"
)
def strftime(self, date_format):
"""
Convert to Index using specified date_format.
Return an Index of formatted strings specified by date_format, which
supports the same string format as the python standard library. Details
of the string format can be found in `python string format
doc <%(URL)s>`__.
Parameters
----------
date_format : str
Date format string (e.g. "%%Y-%%m-%%d").
Returns
-------
ndarray
NumPy ndarray of formatted strings.
See Also
--------
to_datetime : Convert the given argument to datetime.
DatetimeIndex.normalize : Return DatetimeIndex with times to midnight.
DatetimeIndex.round : Round the DatetimeIndex to the specified freq.
DatetimeIndex.floor : Floor the DatetimeIndex to the specified freq.
Examples
--------
>>> rng = pd.date_range(pd.Timestamp("2018-03-10 09:00"),
... periods=3, freq='s')
>>> rng.strftime('%%B %%d, %%Y, %%r')
Index(['March 10, 2018, 09:00:00 AM', 'March 10, 2018, 09:00:01 AM',
'March 10, 2018, 09:00:02 AM'],
dtype='object')
"""
result = self._format_native_types(date_format=date_format, na_rep=np.nan)
return result.astype(object)
class TimelikeOps:
"""
Common ops for TimedeltaIndex/DatetimeIndex, but not PeriodIndex.
"""
_round_doc = """
Perform {op} operation on the data to the specified `freq`.
Parameters
----------
freq : str or Offset
The frequency level to {op} the index to. Must be a fixed
frequency like 'S' (second) not 'ME' (month end). See
:ref:`frequency aliases <timeseries.offset_aliases>` for
a list of possible `freq` values.
ambiguous : 'infer', bool-ndarray, 'NaT', default 'raise'
Only relevant for DatetimeIndex:
- 'infer' will attempt to infer fall dst-transition hours based on
order
- bool-ndarray where True signifies a DST time, False designates
a non-DST time (note that this flag is only applicable for
ambiguous times)
- 'NaT' will return NaT where there are ambiguous times
- 'raise' will raise an AmbiguousTimeError if there are ambiguous
times.
.. versionadded:: 0.24.0
nonexistent : 'shift_forward', 'shift_backward', 'NaT', timedelta, \
default 'raise'
A nonexistent time does not exist in a particular timezone
where clocks moved forward due to DST.
- 'shift_forward' will shift the nonexistent time forward to the
closest existing time
- 'shift_backward' will shift the nonexistent time backward to the
closest existing time
- 'NaT' will return NaT where there are nonexistent times
- timedelta objects will shift nonexistent times by the timedelta
- 'raise' will raise an NonExistentTimeError if there are
nonexistent times.
.. versionadded:: 0.24.0
Returns
-------
DatetimeIndex, TimedeltaIndex, or Series
Index of the same type for a DatetimeIndex or TimedeltaIndex,
or a Series with the same index for a Series.
Raises
------
ValueError if the `freq` cannot be converted.
Examples
--------
**DatetimeIndex**
>>> rng = pd.date_range('1/1/2018 11:59:00', periods=3, freq='min')
>>> rng
DatetimeIndex(['2018-01-01 11:59:00', '2018-01-01 12:00:00',
'2018-01-01 12:01:00'],
dtype='datetime64[ns]', freq='T')
"""
_round_example = """>>> rng.round('H')
DatetimeIndex(['2018-01-01 12:00:00', '2018-01-01 12:00:00',
'2018-01-01 12:00:00'],
dtype='datetime64[ns]', freq=None)
**Series**
>>> pd.Series(rng).dt.round("H")
0 2018-01-01 12:00:00
1 2018-01-01 12:00:00
2 2018-01-01 12:00:00
dtype: datetime64[ns]
"""
_floor_example = """>>> rng.floor('H')
DatetimeIndex(['2018-01-01 11:00:00', '2018-01-01 12:00:00',
'2018-01-01 12:00:00'],
dtype='datetime64[ns]', freq=None)
**Series**
>>> pd.Series(rng).dt.floor("H")
0 2018-01-01 11:00:00
1 2018-01-01 12:00:00
2 2018-01-01 12:00:00
dtype: datetime64[ns]
"""
_ceil_example = """>>> rng.ceil('H')
DatetimeIndex(['2018-01-01 12:00:00', '2018-01-01 12:00:00',
'2018-01-01 13:00:00'],
dtype='datetime64[ns]', freq=None)
**Series**
>>> pd.Series(rng).dt.ceil("H")
0 2018-01-01 12:00:00
1 2018-01-01 12:00:00
2 2018-01-01 13:00:00
dtype: datetime64[ns]
"""
def _round(self, freq, mode, ambiguous, nonexistent):
# round the local times
if is_datetime64tz_dtype(self):
# operate on naive timestamps, then convert back to aware
naive = self.tz_localize(None)
result = naive._round(freq, mode, ambiguous, nonexistent)
aware = result.tz_localize(
self.tz, ambiguous=ambiguous, nonexistent=nonexistent
)
return aware
values = self.view("i8")
result = round_nsint64(values, mode, freq)
result = self._maybe_mask_results(result, fill_value=NaT)
return self._simple_new(result, dtype=self.dtype)
@Appender((_round_doc + _round_example).format(op="round"))
def round(self, freq, ambiguous="raise", nonexistent="raise"):
return self._round(freq, RoundTo.NEAREST_HALF_EVEN, ambiguous, nonexistent)
@Appender((_round_doc + _floor_example).format(op="floor"))
def floor(self, freq, ambiguous="raise", nonexistent="raise"):
return self._round(freq, RoundTo.MINUS_INFTY, ambiguous, nonexistent)
@Appender((_round_doc + _ceil_example).format(op="ceil"))
def ceil(self, freq, ambiguous="raise", nonexistent="raise"):
return self._round(freq, RoundTo.PLUS_INFTY, ambiguous, nonexistent)
def _with_freq(self, freq):
"""
Helper to set our freq in-place, returning self to allow method chaining.
Parameters
----------
freq : DateOffset, None, or "infer"
Returns
-------
self
"""
# GH#29843
if freq is None:
# Always valid
pass
elif len(self) == 0 and isinstance(freq, DateOffset):
# Always valid. In the TimedeltaArray case, we assume this
# is a Tick offset.
pass
else:
# As an internal method, we can ensure this assertion always holds
assert freq == "infer"
freq = frequencies.to_offset(self.inferred_freq)
self._freq = freq
return self
class DatetimeLikeArrayMixin(
ExtensionOpsMixin, AttributesMixin, NDArrayBackedExtensionArray
):
"""
Shared Base/Mixin class for DatetimeArray, TimedeltaArray, PeriodArray
Assumes that __new__/__init__ defines:
_data
_freq
and that the inheriting class has methods:
_generate_range
"""
# ------------------------------------------------------------------
# NDArrayBackedExtensionArray compat
@property
def _ndarray(self) -> np.ndarray:
# NB: A bunch of Interval tests fail if we use ._data
return self.asi8
def _from_backing_data(self: _T, arr: np.ndarray) -> _T:
# Note: we do not retain `freq`
return type(self)(arr, dtype=self.dtype) # type: ignore
# ------------------------------------------------------------------
@property
def ndim(self) -> int:
return self._data.ndim
@property
def shape(self):
return self._data.shape
def reshape(self, *args, **kwargs):
# Note: we drop any freq
data = self._data.reshape(*args, **kwargs)
return type(self)(data, dtype=self.dtype)
def ravel(self, *args, **kwargs):
# Note: we drop any freq
data = self._data.ravel(*args, **kwargs)
return type(self)(data, dtype=self.dtype)
@property
def _box_func(self):
"""
box function to get object from internal representation
"""
raise AbstractMethodError(self)
def _box_values(self, values):
"""
apply box func to passed values
"""
return lib.map_infer(values, self._box_func)
def __iter__(self):
return (self._box_func(v) for v in self.asi8)
@property
def asi8(self) -> np.ndarray:
"""
Integer representation of the values.
Returns
-------
ndarray
An ndarray with int64 dtype.
"""
# do not cache or you'll create a memory leak
return self._data.view("i8")
# ----------------------------------------------------------------
# Rendering Methods
def _format_native_types(self, na_rep="NaT", date_format=None):
"""
Helper method for astype when converting to strings.
Returns
-------
ndarray[str]
"""
raise AbstractMethodError(self)
def _formatter(self, boxed=False):
# TODO: Remove Datetime & DatetimeTZ formatters.
return "'{}'".format
# ----------------------------------------------------------------
# Array-Like / EA-Interface Methods
@property
def nbytes(self):
return self._data.nbytes
def __array__(self, dtype=None) -> np.ndarray:
# used for Timedelta/DatetimeArray, overwritten by PeriodArray
if is_object_dtype(dtype):
return np.array(list(self), dtype=object)
return self._data
@property
def size(self) -> int:
"""The number of elements in this array."""
return np.prod(self.shape)
def __len__(self) -> int:
return len(self._data)
def __getitem__(self, key):
"""
This getitem defers to the underlying array, which by-definition can
only handle list-likes, slices, and integer scalars
"""
if com.is_bool_indexer(key):
# first convert to boolean, because check_array_indexer doesn't
# allow object dtype
if is_object_dtype(key):
key = np.asarray(key, dtype=bool)
key = check_array_indexer(self, key)
key = lib.maybe_booleans_to_slice(key.view(np.uint8))
elif isinstance(key, list) and len(key) == 1 and isinstance(key[0], slice):
# see https://github.com/pandas-dev/pandas/issues/31299, need to allow
# this for now (would otherwise raise in check_array_indexer)
pass
else:
key = check_array_indexer(self, key)
freq = self._get_getitem_freq(key)
result = self._data[key]
if lib.is_scalar(result):
return self._box_func(result)
return self._simple_new(result, dtype=self.dtype, freq=freq)
def _get_getitem_freq(self, key):
"""
Find the `freq` attribute to assign to the result of a __getitem__ lookup.
"""
is_period = is_period_dtype(self.dtype)
if is_period:
freq = self.freq
else:
freq = None
if isinstance(key, slice):
if self.freq is not None and key.step is not None:
freq = key.step * self.freq
else:
freq = self.freq
elif key is Ellipsis:
# GH#21282 indexing with Ellipsis is similar to a full slice,
# should preserve `freq` attribute
freq = self.freq
return freq
def __setitem__(
self,
key: Union[int, Sequence[int], Sequence[bool], slice],
value: Union[NaTType, Any, Sequence[Any]],
) -> None:
# I'm fudging the types a bit here. "Any" above really depends
# on type(self). For PeriodArray, it's Period (or stuff coercible
# to a period in from_sequence). For DatetimeArray, it's Timestamp...
# I don't know if mypy can do that, possibly with Generics.
# https://mypy.readthedocs.io/en/latest/generics.html
if is_list_like(value):
is_slice = isinstance(key, slice)
if lib.is_scalar(key):
raise ValueError("setting an array element with a sequence.")
if not is_slice:
key = cast(Sequence, key)
if len(key) != len(value) and not com.is_bool_indexer(key):
msg = (
f"shape mismatch: value array of length '{len(key)}' "
"does not match indexing result of length "
f"'{len(value)}'."
)
raise ValueError(msg)
elif not len(key):
return
value = self._validate_setitem_value(value)
key = check_array_indexer(self, key)
self._data[key] = value
self._maybe_clear_freq()
def _maybe_clear_freq(self):
# inplace operations like __setitem__ may invalidate the freq of
# DatetimeArray and TimedeltaArray
pass
def astype(self, dtype, copy=True):
# Some notes on cases we don't have to handle here in the base class:
# 1. PeriodArray.astype handles period -> period
# 2. DatetimeArray.astype handles conversion between tz.
# 3. DatetimeArray.astype handles datetime -> period
dtype = pandas_dtype(dtype)
if is_object_dtype(dtype):
return self._box_values(self.asi8.ravel()).reshape(self.shape)
elif is_string_dtype(dtype) and not is_categorical_dtype(dtype):
return self._format_native_types()
elif is_integer_dtype(dtype):
# we deliberately ignore int32 vs. int64 here.
# See https://github.com/pandas-dev/pandas/issues/24381 for more.
values = self.asi8
if is_unsigned_integer_dtype(dtype):
# Again, we ignore int32 vs. int64
values = values.view("uint64")
if copy:
values = values.copy()
return values
elif (
is_datetime_or_timedelta_dtype(dtype)
and not is_dtype_equal(self.dtype, dtype)
) or is_float_dtype(dtype):
# disallow conversion between datetime/timedelta,
# and conversions for any datetimelike to float
msg = f"Cannot cast {type(self).__name__} to dtype {dtype}"
raise TypeError(msg)
elif is_categorical_dtype(dtype):
arr_cls = dtype.construct_array_type()
return arr_cls(self, dtype=dtype)
else:
return np.asarray(self, dtype=dtype)
def view(self, dtype=None):
if dtype is None or dtype is self.dtype:
return type(self)(self._data, dtype=self.dtype)
return self._data.view(dtype=dtype)
# ------------------------------------------------------------------
# ExtensionArray Interface
def unique(self):
result = unique1d(self.asi8)
return type(self)(result, dtype=self.dtype)
@classmethod
def _concat_same_type(cls, to_concat, axis: int = 0):
# do not pass tz to set because tzlocal cannot be hashed
dtypes = {str(x.dtype) for x in to_concat}
if len(dtypes) != 1:
raise ValueError("to_concat must have the same dtype (tz)", dtypes)
obj = to_concat[0]
dtype = obj.dtype
i8values = [x.asi8 for x in to_concat]
values = np.concatenate(i8values, axis=axis)
new_freq = None
if is_period_dtype(dtype):
new_freq = obj.freq
elif axis == 0:
# GH 3232: If the concat result is evenly spaced, we can retain the
# original frequency
to_concat = [x for x in to_concat if len(x)]
if obj.freq is not None and all(x.freq == obj.freq for x in to_concat):
pairs = zip(to_concat[:-1], to_concat[1:])
if all(pair[0][-1] + obj.freq == pair[1][0] for pair in pairs):
new_freq = obj.freq
return cls._simple_new(values, dtype=dtype, freq=new_freq)
def copy(self):
values = self.asi8.copy()
return type(self)._simple_new(values, dtype=self.dtype, freq=self.freq)
def _values_for_factorize(self):
return self.asi8, iNaT
@classmethod
def _from_factorized(cls, values, original):
return cls(values, dtype=original.dtype)
def _values_for_argsort(self):
return self._data
@Appender(ExtensionArray.shift.__doc__)
def shift(self, periods=1, fill_value=None, axis=0):
if not self.size or periods == 0:
return self.copy()
fill_value = self._validate_shift_value(fill_value)
new_values = shift(self._data, periods, axis, fill_value)
return type(self)._simple_new(new_values, dtype=self.dtype)
# ------------------------------------------------------------------
# Validation Methods
# TODO: try to de-duplicate these, ensure identical behavior
def _validate_fill_value(self, fill_value):
"""
If a fill_value is passed to `take` convert it to an i8 representation,
raising ValueError if this is not possible.
Parameters
----------
fill_value : object
Returns
-------
fill_value : np.int64
Raises
------
ValueError
"""
if is_valid_nat_for_dtype(fill_value, self.dtype):
fill_value = iNaT
elif isinstance(fill_value, self._recognized_scalars):
self._check_compatible_with(fill_value)
fill_value = self._scalar_type(fill_value)
fill_value = self._unbox_scalar(fill_value)
else:
raise ValueError(
f"'fill_value' should be a {self._scalar_type}. "
f"Got '{str(fill_value)}'."
)
return fill_value
def _validate_shift_value(self, fill_value):
# TODO(2.0): once this deprecation is enforced, used _validate_fill_value
if is_valid_nat_for_dtype(fill_value, self.dtype):
fill_value = NaT
elif not isinstance(fill_value, self._recognized_scalars):
# only warn if we're not going to raise
if self._scalar_type is Period and lib.is_integer(fill_value):
# kludge for #31971 since Period(integer) tries to cast to str
new_fill = Period._from_ordinal(fill_value, freq=self.freq)
else:
new_fill = self._scalar_type(fill_value)
# stacklevel here is chosen to be correct when called from
# DataFrame.shift or Series.shift
warnings.warn(
f"Passing {type(fill_value)} to shift is deprecated and "
"will raise in a future version, pass "
f"{self._scalar_type.__name__} instead.",
FutureWarning,
stacklevel=10,
)
fill_value = new_fill
fill_value = self._unbox_scalar(fill_value)
return fill_value
def _validate_searchsorted_value(self, value):
if isinstance(value, str):
try:
value = self._scalar_from_string(value)
except ValueError as err:
raise TypeError(
"searchsorted requires compatible dtype or scalar"
) from err
elif is_valid_nat_for_dtype(value, self.dtype):
value = NaT
elif isinstance(value, self._recognized_scalars):
value = self._scalar_type(value)
elif is_list_like(value) and not isinstance(value, type(self)):
value = array(value)
if not type(self)._is_recognized_dtype(value):
raise TypeError(
"searchsorted requires compatible dtype or scalar, "
f"not {type(value).__name__}"
)
if not (isinstance(value, (self._scalar_type, type(self))) or (value is NaT)):
raise TypeError(f"Unexpected type for 'value': {type(value)}")
if isinstance(value, type(self)):
self._check_compatible_with(value)
value = value.asi8
else:
value = self._unbox_scalar(value)
return value
def _validate_setitem_value(self, value):
if lib.is_scalar(value) and not isna(value):
value = com.maybe_box_datetimelike(value)
if is_list_like(value):
value = type(self)._from_sequence(value, dtype=self.dtype)
self._check_compatible_with(value, setitem=True)
value = value.asi8
elif isinstance(value, self._scalar_type):
self._check_compatible_with(value, setitem=True)
value = self._unbox_scalar(value)
elif is_valid_nat_for_dtype(value, self.dtype):
value = iNaT
else:
msg = (
f"'value' should be a '{self._scalar_type.__name__}', 'NaT', "
f"or array of those. Got '{type(value).__name__}' instead."
)
raise TypeError(msg)
return value
def _validate_insert_value(self, value):
if isinstance(value, self._recognized_scalars):
value = self._scalar_type(value)
elif is_valid_nat_for_dtype(value, self.dtype):
# GH#18295
value = NaT
elif lib.is_scalar(value) and isna(value):
raise TypeError(
f"cannot insert {type(self).__name__} with incompatible label"
)
return value
def _validate_where_value(self, other):
if is_valid_nat_for_dtype(other, self.dtype):
other = NaT
elif isinstance(other, self._recognized_scalars):
other = self._scalar_type(other)
self._check_compatible_with(other, setitem=True)
elif not is_list_like(other):
raise TypeError(f"Where requires matching dtype, not {type(other)}")
else:
# Do type inference if necessary up front
# e.g. we passed PeriodIndex.values and got an ndarray of Periods
other = array(other)
other = extract_array(other, extract_numpy=True)
if is_categorical_dtype(other.dtype):
# e.g. we have a Categorical holding self.dtype
if is_dtype_equal(other.categories.dtype, self.dtype):
other = other._internal_get_values()
if not type(self)._is_recognized_dtype(other.dtype):
raise TypeError(f"Where requires matching dtype, not {other.dtype}")
self._check_compatible_with(other, setitem=True)
if lib.is_scalar(other):
other = self._unbox_scalar(other)
else:
other = other.view("i8")
return other
# ------------------------------------------------------------------
# Additional array methods
# These are not part of the EA API, but we implement them because
# pandas assumes they're there.
def searchsorted(self, value, side="left", sorter=None):
"""
Find indices where elements should be inserted to maintain order.
Find the indices into a sorted array `self` such that, if the
corresponding elements in `value` were inserted before the indices,
the order of `self` would be preserved.
Parameters
----------
value : array_like
Values to insert into `self`.
side : {'left', 'right'}, optional
If 'left', the index of the first suitable location found is given.
If 'right', return the last such index. If there is no suitable
index, return either 0 or N (where N is the length of `self`).
sorter : 1-D array_like, optional
Optional array of integer indices that sort `self` into ascending
order. They are typically the result of ``np.argsort``.
Returns
-------
indices : array of ints
Array of insertion points with the same shape as `value`.
"""
value = self._validate_searchsorted_value(value)
# TODO: Use datetime64 semantics for sorting, xref GH#29844
return self.asi8.searchsorted(value, side=side, sorter=sorter)
def repeat(self, repeats, *args, **kwargs):
"""
Repeat elements of an array.
See Also
--------
numpy.ndarray.repeat
"""
nv.validate_repeat(args, kwargs)
values = self._data.repeat(repeats)
return type(self)(values.view("i8"), dtype=self.dtype)
def value_counts(self, dropna=False):
"""
Return a Series containing counts of unique values.
Parameters
----------
dropna : bool, default True
Don't include counts of NaT values.
Returns
-------
Series
"""
from pandas import Series, Index
if dropna:
values = self[~self.isna()]._data
else:
values = self._data
cls = type(self)
result = value_counts(values, sort=False, dropna=dropna)
index = Index(
cls(result.index.view("i8"), dtype=self.dtype), name=result.index.name
)
return Series(result._values, index=index, name=result.name)
def map(self, mapper):
# TODO(GH-23179): Add ExtensionArray.map
# Need to figure out if we want ExtensionArray.map first.
# If so, then we can refactor IndexOpsMixin._map_values to
# a standalone function and call from here..
# Else, just rewrite _map_infer_values to do the right thing.
from pandas import Index
return Index(self).map(mapper).array
# ------------------------------------------------------------------
# Null Handling
def isna(self):
return self._isnan
@property # NB: override with cache_readonly in immutable subclasses
def _isnan(self):
"""
return if each value is nan
"""
return self.asi8 == iNaT
@property # NB: override with cache_readonly in immutable subclasses
def _hasnans(self):
"""
return if I have any nans; enables various perf speedups
"""
return bool(self._isnan.any())
def _maybe_mask_results(self, result, fill_value=iNaT, convert=None):
"""
Parameters
----------
result : a ndarray
fill_value : object, default iNaT
convert : str, dtype or None
Returns
-------
result : ndarray with values replace by the fill_value
mask the result if needed, convert to the provided dtype if its not
None
This is an internal routine.
"""
if self._hasnans:
if convert:
result = result.astype(convert)
if fill_value is None:
fill_value = np.nan
result[self._isnan] = fill_value
return result
def fillna(self, value=None, method=None, limit=None):
# TODO(GH-20300): remove this
# Just overriding to ensure that we avoid an astype(object).
# Either 20300 or a `_values_for_fillna` would avoid this duplication.
if isinstance(value, ABCSeries):
value = value.array
value, method = validate_fillna_kwargs(value, method)
mask = self.isna()
if is_array_like(value):
if len(value) != len(self):
raise ValueError(
f"Length of 'value' does not match. Got ({len(value)}) "
f" expected {len(self)}"
)
value = value[mask]
if mask.any():
if method is not None:
if method == "pad":
func = missing.pad_1d
else:
func = missing.backfill_1d
values = self._data
if not is_period_dtype(self):
# For PeriodArray self._data is i8, which gets copied
# by `func`. Otherwise we need to make a copy manually
# to avoid modifying `self` in-place.
values = values.copy()
new_values = func(values, limit=limit, mask=mask)
if is_datetime64tz_dtype(self):
# we need to pass int64 values to the constructor to avoid
# re-localizing incorrectly
new_values = new_values.view("i8")
new_values = type(self)(new_values, dtype=self.dtype)
else:
# fill with value
new_values = self.copy()
new_values[mask] = value
else:
new_values = self.copy()
return new_values
# ------------------------------------------------------------------
# Frequency Properties/Methods
@property
def freq(self):
"""
Return the frequency object if it is set, otherwise None.
"""
return self._freq
@freq.setter
def freq(self, value):
if value is not None:
value = frequencies.to_offset(value)
self._validate_frequency(self, value)
self._freq = value
@property
def freqstr(self):
"""
Return the frequency object as a string if its set, otherwise None.
"""
if self.freq is None:
return None
return self.freq.freqstr
@property # NB: override with cache_readonly in immutable subclasses
def inferred_freq(self):
"""
Tryies to return a string representing a frequency guess,
generated by infer_freq. Returns None if it can't autodetect the
frequency.
"""
if self.ndim != 1:
return None
try:
return frequencies.infer_freq(self)
except ValueError:
return None
@property # NB: override with cache_readonly in immutable subclasses
def _resolution(self):
return frequencies.Resolution.get_reso_from_freq(self.freqstr)
@property # NB: override with cache_readonly in immutable subclasses
def resolution(self):
"""
Returns day, hour, minute, second, millisecond or microsecond
"""
return frequencies.Resolution.get_str(self._resolution)
@classmethod
def _validate_frequency(cls, index, freq, **kwargs):
"""
Validate that a frequency is compatible with the values of a given
Datetime Array/Index or Timedelta Array/Index
Parameters
----------
index : DatetimeIndex or TimedeltaIndex
The index on which to determine if the given frequency is valid
freq : DateOffset
The frequency to validate
"""
if is_period_dtype(cls):
# Frequency validation is not meaningful for Period Array/Index
return None
inferred = index.inferred_freq
if index.size == 0 or inferred == freq.freqstr:
return None
try:
on_freq = cls._generate_range(
start=index[0], end=None, periods=len(index), freq=freq, **kwargs
)
if not np.array_equal(index.asi8, on_freq.asi8):
raise ValueError
except ValueError as e:
if "non-fixed" in str(e):
# non-fixed frequencies are not meaningful for timedelta64;
# we retain that error message
raise e
# GH#11587 the main way this is reached is if the `np.array_equal`
# check above is False. This can also be reached if index[0]
# is `NaT`, in which case the call to `cls._generate_range` will
# raise a ValueError, which we re-raise with a more targeted
# message.
raise ValueError(
f"Inferred frequency {inferred} from passed values "
f"does not conform to passed frequency {freq.freqstr}"
) from e
# monotonicity/uniqueness properties are called via frequencies.infer_freq,
# see GH#23789
@property
def _is_monotonic_increasing(self):
return algos.is_monotonic(self.asi8, timelike=True)[0]
@property
def _is_monotonic_decreasing(self):
return algos.is_monotonic(self.asi8, timelike=True)[1]
@property
def _is_unique(self):
return len(unique1d(self.asi8)) == len(self)
# ------------------------------------------------------------------
# Arithmetic Methods
_create_comparison_method = classmethod(_datetimelike_array_cmp)
# pow is invalid for all three subclasses; TimedeltaArray will override
# the multiplication and division ops
__pow__ = make_invalid_op("__pow__")
__rpow__ = make_invalid_op("__rpow__")
__mul__ = make_invalid_op("__mul__")
__rmul__ = make_invalid_op("__rmul__")
__truediv__ = make_invalid_op("__truediv__")
__rtruediv__ = make_invalid_op("__rtruediv__")
__floordiv__ = make_invalid_op("__floordiv__")
__rfloordiv__ = make_invalid_op("__rfloordiv__")
__mod__ = make_invalid_op("__mod__")
__rmod__ = make_invalid_op("__rmod__")
__divmod__ = make_invalid_op("__divmod__")
__rdivmod__ = make_invalid_op("__rdivmod__")
def _add_datetimelike_scalar(self, other):
# Overridden by TimedeltaArray
raise TypeError(f"cannot add {type(self).__name__} and {type(other).__name__}")
_add_datetime_arraylike = _add_datetimelike_scalar
def _sub_datetimelike_scalar(self, other):
# Overridden by DatetimeArray
assert other is not NaT
raise TypeError(f"cannot subtract a datelike from a {type(self).__name__}")
_sub_datetime_arraylike = _sub_datetimelike_scalar
def _sub_period(self, other):
# Overridden by PeriodArray
raise TypeError(f"cannot subtract Period from a {type(self).__name__}")
def _add_offset(self, offset):
raise AbstractMethodError(self)
def _add_timedeltalike_scalar(self, other):
"""
Add a delta of a timedeltalike
Returns
-------
Same type as self
"""
if isna(other):
# i.e np.timedelta64("NaT"), not recognized by delta_to_nanoseconds
new_values = np.empty(self.shape, dtype="i8")
new_values[:] = iNaT
return type(self)(new_values, dtype=self.dtype)
inc = delta_to_nanoseconds(other)
new_values = checked_add_with_arr(self.asi8, inc, arr_mask=self._isnan).view(
"i8"
)
new_values = self._maybe_mask_results(new_values)
new_freq = None
if isinstance(self.freq, Tick) or is_period_dtype(self.dtype):
# adding a scalar preserves freq
new_freq = self.freq
return type(self)(new_values, dtype=self.dtype, freq=new_freq)
def _add_timedelta_arraylike(self, other):
"""
Add a delta of a TimedeltaIndex
Returns
-------
Same type as self
"""
# overridden by PeriodArray
if len(self) != len(other):
raise ValueError("cannot add indices of unequal length")
if isinstance(other, np.ndarray):
# ndarray[timedelta64]; wrap in TimedeltaIndex for op
from pandas.core.arrays import TimedeltaArray
other = TimedeltaArray._from_sequence(other)
self_i8 = self.asi8
other_i8 = other.asi8
new_values = checked_add_with_arr(
self_i8, other_i8, arr_mask=self._isnan, b_mask=other._isnan
)
if self._hasnans or other._hasnans:
mask = (self._isnan) | (other._isnan)
new_values[mask] = iNaT
return type(self)(new_values, dtype=self.dtype)
def _add_nat(self):
"""
Add pd.NaT to self
"""
if is_period_dtype(self):
raise TypeError(
f"Cannot add {type(self).__name__} and {type(NaT).__name__}"
)
# GH#19124 pd.NaT is treated like a timedelta for both timedelta
# and datetime dtypes
result = np.zeros(self.shape, dtype=np.int64)
result.fill(iNaT)
return type(self)(result, dtype=self.dtype, freq=None)
def _sub_nat(self):
"""
Subtract pd.NaT from self
"""
# GH#19124 Timedelta - datetime is not in general well-defined.
# We make an exception for pd.NaT, which in this case quacks
# like a timedelta.
# For datetime64 dtypes by convention we treat NaT as a datetime, so
# this subtraction returns a timedelta64 dtype.
# For period dtype, timedelta64 is a close-enough return dtype.
result = np.zeros(self.shape, dtype=np.int64)
result.fill(iNaT)
return result.view("timedelta64[ns]")
def _sub_period_array(self, other):
"""
Subtract a Period Array/Index from self. This is only valid if self
is itself a Period Array/Index, raises otherwise. Both objects must
have the same frequency.
Parameters
----------
other : PeriodIndex or PeriodArray
Returns
-------
result : np.ndarray[object]
Array of DateOffset objects; nulls represented by NaT.
"""
if not is_period_dtype(self):
raise TypeError(
f"cannot subtract {other.dtype}-dtype from {type(self).__name__}"
)
if self.freq != other.freq:
msg = DIFFERENT_FREQ.format(
cls=type(self).__name__, own_freq=self.freqstr, other_freq=other.freqstr
)
raise IncompatibleFrequency(msg)
new_values = checked_add_with_arr(
self.asi8, -other.asi8, arr_mask=self._isnan, b_mask=other._isnan
)
new_values = np.array([self.freq.base * x for x in new_values])
if self._hasnans or other._hasnans:
mask = (self._isnan) | (other._isnan)
new_values[mask] = NaT
return new_values
def _addsub_object_array(self, other: np.ndarray, op):
"""
Add or subtract array-like of DateOffset objects
Parameters
----------
other : np.ndarray[object]
op : {operator.add, operator.sub}
Returns
-------
result : same class as self
"""
assert op in [operator.add, operator.sub]
if len(other) == 1:
return op(self, other[0])
warnings.warn(
"Adding/subtracting array of DateOffsets to "
f"{type(self).__name__} not vectorized",
PerformanceWarning,
)
# Caller is responsible for broadcasting if necessary
assert self.shape == other.shape, (self.shape, other.shape)
res_values = op(self.astype("O"), np.array(other))
result = array(res_values.ravel())
result = extract_array(result, extract_numpy=True).reshape(self.shape)
return result
def _time_shift(self, periods, freq=None):
"""
Shift each value by `periods`.
Note this is different from ExtensionArray.shift, which
shifts the *position* of each element, padding the end with
missing values.
Parameters
----------
periods : int
Number of periods to shift by.
freq : pandas.DateOffset, pandas.Timedelta, or str
Frequency increment to shift by.
"""
if freq is not None and freq != self.freq:
if isinstance(freq, str):
freq = frequencies.to_offset(freq)
offset = periods * freq
result = self + offset
return result
if periods == 0:
# immutable so OK
return self.copy()
if self.freq is None:
raise NullFrequencyError("Cannot shift with no freq")
start = self[0] + periods * self.freq
end = self[-1] + periods * self.freq
# Note: in the DatetimeTZ case, _generate_range will infer the
# appropriate timezone from `start` and `end`, so tz does not need
# to be passed explicitly.
return self._generate_range(start=start, end=end, periods=None, freq=self.freq)
@unpack_zerodim_and_defer("__add__")
def __add__(self, other):
# scalar others
if other is NaT:
result = self._add_nat()
elif isinstance(other, (Tick, timedelta, np.timedelta64)):
result = self._add_timedeltalike_scalar(other)
elif isinstance(other, DateOffset):
# specifically _not_ a Tick
result = self._add_offset(other)
elif isinstance(other, (datetime, np.datetime64)):
result = self._add_datetimelike_scalar(other)
elif lib.is_integer(other):
# This check must come after the check for np.timedelta64
# as is_integer returns True for these
if not is_period_dtype(self):
raise integer_op_not_supported(self)
result = self._time_shift(other)
# array-like others
elif is_timedelta64_dtype(other):
# TimedeltaIndex, ndarray[timedelta64]
result = self._add_timedelta_arraylike(other)
elif is_object_dtype(other):
# e.g. Array/Index of DateOffset objects
result = self._addsub_object_array(other, operator.add)
elif is_datetime64_dtype(other) or is_datetime64tz_dtype(other):
# DatetimeIndex, ndarray[datetime64]
return self._add_datetime_arraylike(other)
elif is_integer_dtype(other):
if not is_period_dtype(self):
raise integer_op_not_supported(self)
result = self._addsub_int_array(other, operator.add)
else:
# Includes Categorical, other ExtensionArrays
# For PeriodDtype, if self is a TimedeltaArray and other is a
# PeriodArray with a timedelta-like (i.e. Tick) freq, this
# operation is valid. Defer to the PeriodArray implementation.
# In remaining cases, this will end up raising TypeError.
return NotImplemented
if is_timedelta64_dtype(result) and isinstance(result, np.ndarray):
from pandas.core.arrays import TimedeltaArray
return TimedeltaArray(result)
return result
def __radd__(self, other):
# alias for __add__
return self.__add__(other)
@unpack_zerodim_and_defer("__sub__")
def __sub__(self, other):
# scalar others
if other is NaT:
result = self._sub_nat()
elif isinstance(other, (Tick, timedelta, np.timedelta64)):
result = self._add_timedeltalike_scalar(-other)
elif isinstance(other, DateOffset):
# specifically _not_ a Tick
result = self._add_offset(-other)
elif isinstance(other, (datetime, np.datetime64)):
result = self._sub_datetimelike_scalar(other)
elif lib.is_integer(other):
# This check must come after the check for np.timedelta64
# as is_integer returns True for these
if not is_period_dtype(self):
raise integer_op_not_supported(self)
result = self._time_shift(-other)
elif isinstance(other, Period):
result = self._sub_period(other)
# array-like others
elif is_timedelta64_dtype(other):
# TimedeltaIndex, ndarray[timedelta64]
result = self._add_timedelta_arraylike(-other)
elif is_object_dtype(other):
# e.g. Array/Index of DateOffset objects
result = self._addsub_object_array(other, operator.sub)
elif is_datetime64_dtype(other) or is_datetime64tz_dtype(other):
# DatetimeIndex, ndarray[datetime64]
result = self._sub_datetime_arraylike(other)
elif is_period_dtype(other):
# PeriodIndex
result = self._sub_period_array(other)
elif is_integer_dtype(other):
if not is_period_dtype(self):
raise integer_op_not_supported(self)
result = self._addsub_int_array(other, operator.sub)
else:
# Includes ExtensionArrays, float_dtype
return NotImplemented
if is_timedelta64_dtype(result) and isinstance(result, np.ndarray):
from pandas.core.arrays import TimedeltaArray
return TimedeltaArray(result)
return result
def __rsub__(self, other):
if is_datetime64_any_dtype(other) and is_timedelta64_dtype(self.dtype):
# ndarray[datetime64] cannot be subtracted from self, so
# we need to wrap in DatetimeArray/Index and flip the operation
if lib.is_scalar(other):
# i.e. np.datetime64 object
return Timestamp(other) - self
if not isinstance(other, DatetimeLikeArrayMixin):
# Avoid down-casting DatetimeIndex
from pandas.core.arrays import DatetimeArray
other = DatetimeArray(other)
return other - self
elif (
is_datetime64_any_dtype(self.dtype)
and hasattr(other, "dtype")
and not is_datetime64_any_dtype(other.dtype)
):
# GH#19959 datetime - datetime is well-defined as timedelta,
# but any other type - datetime is not well-defined.
raise TypeError(
f"cannot subtract {type(self).__name__} from {type(other).__name__}"
)
elif is_period_dtype(self.dtype) and is_timedelta64_dtype(other):
# TODO: Can we simplify/generalize these cases at all?
raise TypeError(f"cannot subtract {type(self).__name__} from {other.dtype}")
elif is_timedelta64_dtype(self.dtype):
if lib.is_integer(other) or is_integer_dtype(other):
# need to subtract before negating, since that flips freq
# -self flips self.freq, messing up results
return -(self - other)
return (-self) + other
return -(self - other)
def __iadd__(self, other):
result = self + other
self[:] = result[:]
if not is_period_dtype(self):
# restore freq, which is invalidated by setitem
self._freq = result._freq
return self
def __isub__(self, other):
result = self - other
self[:] = result[:]
if not is_period_dtype(self):
# restore freq, which is invalidated by setitem
self._freq = result._freq
return self
# --------------------------------------------------------------
# Reductions
def _reduce(self, name, axis=0, skipna=True, **kwargs):
op = getattr(self, name, None)
if op:
return op(skipna=skipna, **kwargs)
else:
return super()._reduce(name, skipna, **kwargs)
def min(self, axis=None, skipna=True, *args, **kwargs):
"""
Return the minimum value of the Array or minimum along
an axis.
See Also
--------
numpy.ndarray.min
Index.min : Return the minimum value in an Index.
Series.min : Return the minimum value in a Series.
"""
nv.validate_min(args, kwargs)
nv.validate_minmax_axis(axis)
result = nanops.nanmin(self.asi8, skipna=skipna, mask=self.isna())
if isna(result):
# Period._from_ordinal does not handle np.nan gracefully
return NaT
return self._box_func(result)
def max(self, axis=None, skipna=True, *args, **kwargs):
"""
Return the maximum value of the Array or maximum along
an axis.
See Also
--------
numpy.ndarray.max
Index.max : Return the maximum value in an Index.
Series.max : Return the maximum value in a Series.
"""
# TODO: skipna is broken with max.
# See https://github.com/pandas-dev/pandas/issues/24265
nv.validate_max(args, kwargs)
nv.validate_minmax_axis(axis)
mask = self.isna()
if skipna:
values = self[~mask].asi8
elif mask.any():
return NaT
else:
values = self.asi8
if not len(values):
# short-circuit for empty max / min
return NaT
result = nanops.nanmax(values, skipna=skipna)
# Don't have to worry about NA `result`, since no NA went in.
return self._box_func(result)
def mean(self, skipna=True):
"""
Return the mean value of the Array.
.. versionadded:: 0.25.0
Parameters
----------
skipna : bool, default True
Whether to ignore any NaT elements.
Returns
-------
scalar
Timestamp or Timedelta.
See Also
--------
numpy.ndarray.mean : Returns the average of array elements along a given axis.
Series.mean : Return the mean value in a Series.
Notes
-----
mean is only defined for Datetime and Timedelta dtypes, not for Period.
"""
if is_period_dtype(self):
# See discussion in GH#24757
raise TypeError(
f"mean is not implemented for {type(self).__name__} since the "
"meaning is ambiguous. An alternative is "
"obj.to_timestamp(how='start').mean()"
)
mask = self.isna()
if skipna:
values = self[~mask]
elif mask.any():
return NaT
else:
values = self
if not len(values):
# short-circuit for empty max / min
return NaT
result = nanops.nanmean(values.view("i8"), skipna=skipna)
# Don't have to worry about NA `result`, since no NA went in.
return self._box_func(result)
DatetimeLikeArrayMixin._add_comparison_ops()
# -------------------------------------------------------------------
# Shared Constructor Helpers
def validate_periods(periods):
"""
If a `periods` argument is passed to the Datetime/Timedelta Array/Index
constructor, cast it to an integer.
Parameters
----------
periods : None, float, int
Returns
-------
periods : None or int
Raises
------
TypeError
if periods is None, float, or int
"""
if periods is not None:
if lib.is_float(periods):
periods = int(periods)
elif not lib.is_integer(periods):
raise TypeError(f"periods must be a number, got {periods}")
return periods
def validate_endpoints(closed):
"""
Check that the `closed` argument is among [None, "left", "right"]
Parameters
----------
closed : {None, "left", "right"}
Returns
-------
left_closed : bool
right_closed : bool
Raises
------
ValueError : if argument is not among valid values
"""
left_closed = False
right_closed = False
if closed is None:
left_closed = True
right_closed = True
elif closed == "left":
left_closed = True
elif closed == "right":
right_closed = True
else:
raise ValueError("Closed has to be either 'left', 'right' or None")
return left_closed, right_closed
def validate_inferred_freq(freq, inferred_freq, freq_infer):
"""
If the user passes a freq and another freq is inferred from passed data,
require that they match.
Parameters
----------
freq : DateOffset or None
inferred_freq : DateOffset or None
freq_infer : bool
Returns
-------
freq : DateOffset or None
freq_infer : bool
Notes
-----
We assume at this point that `maybe_infer_freq` has been called, so
`freq` is either a DateOffset object or None.
"""
if inferred_freq is not None:
if freq is not None and freq != inferred_freq:
raise ValueError(
f"Inferred frequency {inferred_freq} from passed "
"values does not conform to passed frequency "
f"{freq.freqstr}"
)
elif freq is None:
freq = inferred_freq
freq_infer = False
return freq, freq_infer
def maybe_infer_freq(freq):
"""
Comparing a DateOffset to the string "infer" raises, so we need to
be careful about comparisons. Make a dummy variable `freq_infer` to
signify the case where the given freq is "infer" and set freq to None
to avoid comparison trouble later on.
Parameters
----------
freq : {DateOffset, None, str}
Returns
-------
freq : {DateOffset, None}
freq_infer : bool
Whether we should inherit the freq of passed data.
"""
freq_infer = False
if not isinstance(freq, DateOffset):
# if a passed freq is None, don't infer automatically
if freq != "infer":
freq = frequencies.to_offset(freq)
else:
freq_infer = True
freq = None
return freq, freq_infer
from datetime import datetime, timedelta
import operator
from typing import Any, Sequence, Type, Union, cast
import warnings
import numpy as np
from pandas._libs import NaT, NaTType, Timestamp, algos, iNaT, lib
from pandas._libs.tslibs.c_timestamp import integer_op_not_supported
from pandas._libs.tslibs.period import DIFFERENT_FREQ, IncompatibleFrequency, Period
from pandas._libs.tslibs.timedeltas import Timedelta, delta_to_nanoseconds
from pandas._libs.tslibs.timestamps import RoundTo, round_nsint64
from pandas._typing import DatetimeLikeScalar
from pandas.compat import set_function_name
from pandas.compat.numpy import function as nv
from pandas.errors import AbstractMethodError, NullFrequencyError, PerformanceWarning
from pandas.util._decorators import Appender, Substitution
from pandas.util._validators import validate_fillna_kwargs
from pandas.core.dtypes.common import (
is_categorical_dtype,
is_datetime64_any_dtype,
is_datetime64_dtype,
is_datetime64tz_dtype,
is_datetime_or_timedelta_dtype,
is_dtype_equal,
is_float_dtype,
is_integer_dtype,
is_list_like,
is_object_dtype,
is_period_dtype,
is_string_dtype,
is_timedelta64_dtype,
is_unsigned_integer_dtype,
pandas_dtype,
)
from pandas.core.dtypes.generic import ABCSeries
from pandas.core.dtypes.inference import is_array_like
from pandas.core.dtypes.missing import is_valid_nat_for_dtype, isna
from pandas.core import missing, nanops, ops
from pandas.core.algorithms import checked_add_with_arr, unique1d, value_counts
from pandas.core.array_algos.transforms import shift
from pandas.core.arrays._mixins import _T, NDArrayBackedExtensionArray
from pandas.core.arrays.base import ExtensionArray, ExtensionOpsMixin
import pandas.core.common as com
from pandas.core.construction import array, extract_array
from pandas.core.indexers import check_array_indexer
from pandas.core.ops.common import unpack_zerodim_and_defer
from pandas.core.ops.invalid import invalid_comparison, make_invalid_op
from pandas.tseries import frequencies
from pandas.tseries.offsets import DateOffset, Tick
def _datetimelike_array_cmp(cls, op):
"""
Wrap comparison operations to convert Timestamp/Timedelta/Period-like to
boxed scalars/arrays.
"""
opname = f"__{op.__name__}__"
nat_result = opname == "__ne__"
class InvalidComparison(Exception):
pass
def _validate_comparison_value(self, other):
if isinstance(other, str):
try:
# GH#18435 strings get a pass from tzawareness compat
other = self._scalar_from_string(other)
except ValueError:
# failed to parse as Timestamp/Timedelta/Period
raise InvalidComparison(other)
if isinstance(other, self._recognized_scalars) or other is NaT:
other = self._scalar_type(other)
self._check_compatible_with(other)
elif not is_list_like(other):
raise InvalidComparison(other)
elif len(other) != len(self):
raise ValueError("Lengths must match")
else:
if isinstance(other, list):
# TODO: could use pd.Index to do inference?
other = np.array(other)
if not isinstance(other, (np.ndarray, type(self))):
raise InvalidComparison(other)
elif is_object_dtype(other.dtype):
pass
elif not type(self)._is_recognized_dtype(other.dtype):
raise InvalidComparison(other)
else:
# For PeriodDType this casting is unnecessary
# TODO: use Index to do inference?
other = type(self)._from_sequence(other)
self._check_compatible_with(other)
return other
@unpack_zerodim_and_defer(opname)
def wrapper(self, other):
try:
other = _validate_comparison_value(self, other)
except InvalidComparison:
return invalid_comparison(self, other, op)
dtype = getattr(other, "dtype", None)
if is_object_dtype(dtype):
# We have to use comp_method_OBJECT_ARRAY instead of numpy
# comparison otherwise it would fail to raise when
# comparing tz-aware and tz-naive
with np.errstate(all="ignore"):
result = ops.comp_method_OBJECT_ARRAY(op, self.astype(object), other)
return result
if isinstance(other, self._scalar_type) or other is NaT:
other_i8 = self._unbox_scalar(other)
else:
# Then type(other) == type(self)
other_i8 = other.asi8
result = op(self.asi8, other_i8)
o_mask = isna(other)
if self._hasnans | np.any(o_mask):
result[self._isnan | o_mask] = nat_result
return result
return set_function_name(wrapper, opname, cls)
class AttributesMixin:
_data: np.ndarray
@classmethod
def _simple_new(cls, values: np.ndarray, **kwargs):
raise AbstractMethodError(cls)
@property
def _scalar_type(self) -> Type[DatetimeLikeScalar]:
"""
The scalar associated with this datelike
* PeriodArray : Period
* DatetimeArray : Timestamp
* TimedeltaArray : Timedelta
"""
raise AbstractMethodError(self)
def _scalar_from_string(
self, value: str
) -> Union[Period, Timestamp, Timedelta, NaTType]:
"""
Construct a scalar type from a string.
Parameters
----------
value : str
Returns
-------
Period, Timestamp, or Timedelta, or NaT
Whatever the type of ``self._scalar_type`` is.
Notes
-----
This should call ``self._check_compatible_with`` before
unboxing the result.
"""
raise AbstractMethodError(self)
def _unbox_scalar(self, value: Union[Period, Timestamp, Timedelta, NaTType]) -> int:
"""
Unbox the integer value of a scalar `value`.
Parameters
----------
value : Union[Period, Timestamp, Timedelta]
Returns
-------
int
Examples
--------
>>> self._unbox_scalar(Timedelta("10s")) # doctest: +SKIP
10000000000
"""
raise AbstractMethodError(self)
def _check_compatible_with(
self, other: Union[Period, Timestamp, Timedelta, NaTType], setitem: bool = False
) -> None:
"""
Verify that `self` and `other` are compatible.
* DatetimeArray verifies that the timezones (if any) match
* PeriodArray verifies that the freq matches
* Timedelta has no verification
In each case, NaT is considered compatible.
Parameters
----------
other
setitem : bool, default False
For __setitem__ we may have stricter compatibility resrictions than
for comparisons.
Raises
------
Exception
"""
raise AbstractMethodError(self)
class DatelikeOps:
"""
Common ops for DatetimeIndex/PeriodIndex, but not TimedeltaIndex.
"""
@Substitution(
URL="https://docs.python.org/3/library/datetime.html"
"#strftime-and-strptime-behavior"
)
def strftime(self, date_format):
"""
Convert to Index using specified date_format.
Return an Index of formatted strings specified by date_format, which
supports the same string format as the python standard library. Details
of the string format can be found in `python string format
doc <%(URL)s>`__.
Parameters
----------
date_format : str
Date format string (e.g. "%%Y-%%m-%%d").
Returns
-------
ndarray
NumPy ndarray of formatted strings.
See Also
--------
to_datetime : Convert the given argument to datetime.
DatetimeIndex.normalize : Return DatetimeIndex with times to midnight.
DatetimeIndex.round : Round the DatetimeIndex to the specified freq.
DatetimeIndex.floor : Floor the DatetimeIndex to the specified freq.
Examples
--------
>>> rng = pd.date_range(pd.Timestamp("2018-03-10 09:00"),
... periods=3, freq='s')
>>> rng.strftime('%%B %%d, %%Y, %%r')
Index(['March 10, 2018, 09:00:00 AM', 'March 10, 2018, 09:00:01 AM',
'March 10, 2018, 09:00:02 AM'],
dtype='object')
"""
result = self._format_native_types(date_format=date_format, na_rep=np.nan)
return result.astype(object)
class TimelikeOps:
"""
Common ops for TimedeltaIndex/DatetimeIndex, but not PeriodIndex.
"""
_round_doc = """
Perform {op} operation on the data to the specified `freq`.
Parameters
----------
freq : str or Offset
The frequency level to {op} the index to. Must be a fixed
frequency like 'S' (second) not 'ME' (month end). See
:ref:`frequency aliases <timeseries.offset_aliases>` for
a list of possible `freq` values.
ambiguous : 'infer', bool-ndarray, 'NaT', default 'raise'
Only relevant for DatetimeIndex:
- 'infer' will attempt to infer fall dst-transition hours based on
order
- bool-ndarray where True signifies a DST time, False designates
a non-DST time (note that this flag is only applicable for
ambiguous times)
- 'NaT' will return NaT where there are ambiguous times
- 'raise' will raise an AmbiguousTimeError if there are ambiguous
times.
.. versionadded:: 0.24.0
nonexistent : 'shift_forward', 'shift_backward', 'NaT', timedelta, \
default 'raise'
A nonexistent time does not exist in a particular timezone
where clocks moved forward due to DST.
- 'shift_forward' will shift the nonexistent time forward to the
closest existing time
- 'shift_backward' will shift the nonexistent time backward to the
closest existing time
- 'NaT' will return NaT where there are nonexistent times
- timedelta objects will shift nonexistent times by the timedelta
- 'raise' will raise an NonExistentTimeError if there are
nonexistent times.
.. versionadded:: 0.24.0
Returns
-------
DatetimeIndex, TimedeltaIndex, or Series
Index of the same type for a DatetimeIndex or TimedeltaIndex,
or a Series with the same index for a Series.
Raises
------
ValueError if the `freq` cannot be converted.
Examples
--------
**DatetimeIndex**
>>> rng = pd.date_range('1/1/2018 11:59:00', periods=3, freq='min')
>>> rng
DatetimeIndex(['2018-01-01 11:59:00', '2018-01-01 12:00:00',
'2018-01-01 12:01:00'],
dtype='datetime64[ns]', freq='T')
"""
_round_example = """>>> rng.round('H')
DatetimeIndex(['2018-01-01 12:00:00', '2018-01-01 12:00:00',
'2018-01-01 12:00:00'],
dtype='datetime64[ns]', freq=None)
**Series**
>>> pd.Series(rng).dt.round("H")
0 2018-01-01 12:00:00
1 2018-01-01 12:00:00
2 2018-01-01 12:00:00
dtype: datetime64[ns]
"""
_floor_example = """>>> rng.floor('H')
DatetimeIndex(['2018-01-01 11:00:00', '2018-01-01 12:00:00',
'2018-01-01 12:00:00'],
dtype='datetime64[ns]', freq=None)
**Series**
>>> pd.Series(rng).dt.floor("H")
0 2018-01-01 11:00:00
1 2018-01-01 12:00:00
2 2018-01-01 12:00:00
dtype: datetime64[ns]
"""
_ceil_example = """>>> rng.ceil('H')
DatetimeIndex(['2018-01-01 12:00:00', '2018-01-01 12:00:00',
'2018-01-01 13:00:00'],
dtype='datetime64[ns]', freq=None)
**Series**
>>> pd.Series(rng).dt.ceil("H")
0 2018-01-01 12:00:00
1 2018-01-01 12:00:00
2 2018-01-01 13:00:00
dtype: datetime64[ns]
"""
def _round(self, freq, mode, ambiguous, nonexistent):
# round the local times
if is_datetime64tz_dtype(self):
# operate on naive timestamps, then convert back to aware
naive = self.tz_localize(None)
result = naive._round(freq, mode, ambiguous, nonexistent)
aware = result.tz_localize(
self.tz, ambiguous=ambiguous, nonexistent=nonexistent
)
return aware
values = self.view("i8")
result = round_nsint64(values, mode, freq)
result = self._maybe_mask_results(result, fill_value=NaT)
return self._simple_new(result, dtype=self.dtype)
@Appender((_round_doc + _round_example).format(op="round"))
def round(self, freq, ambiguous="raise", nonexistent="raise"):
return self._round(freq, RoundTo.NEAREST_HALF_EVEN, ambiguous, nonexistent)
@Appender((_round_doc + _floor_example).format(op="floor"))
def floor(self, freq, ambiguous="raise", nonexistent="raise"):
return self._round(freq, RoundTo.MINUS_INFTY, ambiguous, nonexistent)
@Appender((_round_doc + _ceil_example).format(op="ceil"))
def ceil(self, freq, ambiguous="raise", nonexistent="raise"):
return self._round(freq, RoundTo.PLUS_INFTY, ambiguous, nonexistent)
def _with_freq(self, freq):
"""
Helper to set our freq in-place, returning self to allow method chaining.
Parameters
----------
freq : DateOffset, None, or "infer"
Returns
-------
self
"""
# GH#29843
if freq is None:
# Always valid
pass
elif len(self) == 0 and isinstance(freq, DateOffset):
# Always valid. In the TimedeltaArray case, we assume this
# is a Tick offset.
pass
else:
# As an internal method, we can ensure this assertion always holds
assert freq == "infer"
freq = frequencies.to_offset(self.inferred_freq)
self._freq = freq
return self
class DatetimeLikeArrayMixin(
ExtensionOpsMixin, AttributesMixin, NDArrayBackedExtensionArray
):
"""
Shared Base/Mixin class for DatetimeArray, TimedeltaArray, PeriodArray
Assumes that __new__/__init__ defines:
_data
_freq
and that the inheriting class has methods:
_generate_range
"""
# ------------------------------------------------------------------
# NDArrayBackedExtensionArray compat
@property
def _ndarray(self) -> np.ndarray:
# NB: A bunch of Interval tests fail if we use ._data
return self.asi8
def _from_backing_data(self: _T, arr: np.ndarray) -> _T:
# Note: we do not retain `freq`
return type(self)(arr, dtype=self.dtype) # type: ignore
# ------------------------------------------------------------------
@property
def ndim(self) -> int:
return self._data.ndim
@property
def shape(self):
return self._data.shape
def reshape(self, *args, **kwargs):
# Note: we drop any freq
data = self._data.reshape(*args, **kwargs)
return type(self)(data, dtype=self.dtype)
def ravel(self, *args, **kwargs):
# Note: we drop any freq
data = self._data.ravel(*args, **kwargs)
return type(self)(data, dtype=self.dtype)
@property
def _box_func(self):
"""
box function to get object from internal representation
"""
raise AbstractMethodError(self)
def _box_values(self, values):
"""
apply box func to passed values
"""
return lib.map_infer(values, self._box_func)
def __iter__(self):
return (self._box_func(v) for v in self.asi8)
@property
def asi8(self) -> np.ndarray:
"""
Integer representation of the values.
Returns
-------
ndarray
An ndarray with int64 dtype.
"""
# do not cache or you'll create a memory leak
return self._data.view("i8")
# ----------------------------------------------------------------
# Rendering Methods
def _format_native_types(self, na_rep="NaT", date_format=None):
"""
Helper method for astype when converting to strings.
Returns
-------
ndarray[str]
"""
raise AbstractMethodError(self)
def _formatter(self, boxed=False):
# TODO: Remove Datetime & DatetimeTZ formatters.
return "'{}'".format
# ----------------------------------------------------------------
# Array-Like / EA-Interface Methods
@property
def nbytes(self):
return self._data.nbytes
def __array__(self, dtype=None) -> np.ndarray:
# used for Timedelta/DatetimeArray, overwritten by PeriodArray
if is_object_dtype(dtype):
return np.array(list(self), dtype=object)
return self._data
@property
def size(self) -> int:
"""The number of elements in this array."""
return np.prod(self.shape)
def __len__(self) -> int:
return len(self._data)
def __getitem__(self, key):
"""
This getitem defers to the underlying array, which by-definition can
only handle list-likes, slices, and integer scalars
"""
if com.is_bool_indexer(key):
# first convert to boolean, because check_array_indexer doesn't
# allow object dtype
if is_object_dtype(key):
key = np.asarray(key, dtype=bool)
key = check_array_indexer(self, key)
key = lib.maybe_booleans_to_slice(key.view(np.uint8))
elif isinstance(key, list) and len(key) == 1 and isinstance(key[0], slice):
# see https://github.com/pandas-dev/pandas/issues/31299, need to allow
# this for now (would otherwise raise in check_array_indexer)
pass
else:
key = check_array_indexer(self, key)
freq = self._get_getitem_freq(key)
result = self._data[key]
if lib.is_scalar(result):
return self._box_func(result)
return self._simple_new(result, dtype=self.dtype, freq=freq)
def _get_getitem_freq(self, key):
"""
Find the `freq` attribute to assign to the result of a __getitem__ lookup.
"""
is_period = is_period_dtype(self.dtype)
if is_period:
freq = self.freq
else:
freq = None
if isinstance(key, slice):
if self.freq is not None and key.step is not None:
freq = key.step * self.freq
else:
freq = self.freq
elif key is Ellipsis:
# GH#21282 indexing with Ellipsis is similar to a full slice,
# should preserve `freq` attribute
freq = self.freq
return freq
def __setitem__(
self,
key: Union[int, Sequence[int], Sequence[bool], slice],
value: Union[NaTType, Any, Sequence[Any]],
) -> None:
# I'm fudging the types a bit here. "Any" above really depends
# on type(self). For PeriodArray, it's Period (or stuff coercible
# to a period in from_sequence). For DatetimeArray, it's Timestamp...
# I don't know if mypy can do that, possibly with Generics.
# https://mypy.readthedocs.io/en/latest/generics.html
if is_list_like(value):
is_slice = isinstance(key, slice)
if lib.is_scalar(key):
raise ValueError("setting an array element with a sequence.")
if not is_slice:
key = cast(Sequence, key)
if len(key) != len(value) and not com.is_bool_indexer(key):
msg = (
f"shape mismatch: value array of length '{len(key)}' "
"does not match indexing result of length "
f"'{len(value)}'."
)
raise ValueError(msg)
elif not len(key):
return
value = self._validate_setitem_value(value)
key = check_array_indexer(self, key)
self._data[key] = value
self._maybe_clear_freq()
def _maybe_clear_freq(self):
# inplace operations like __setitem__ may invalidate the freq of
# DatetimeArray and TimedeltaArray
pass
def astype(self, dtype, copy=True):
# Some notes on cases we don't have to handle here in the base class:
# 1. PeriodArray.astype handles period -> period
# 2. DatetimeArray.astype handles conversion between tz.
# 3. DatetimeArray.astype handles datetime -> period
dtype = pandas_dtype(dtype)
if is_object_dtype(dtype):
return self._box_values(self.asi8.ravel()).reshape(self.shape)
elif is_string_dtype(dtype) and not is_categorical_dtype(dtype):
return self._format_native_types()
elif is_integer_dtype(dtype):
# we deliberately ignore int32 vs. int64 here.
# See https://github.com/pandas-dev/pandas/issues/24381 for more.
values = self.asi8
if is_unsigned_integer_dtype(dtype):
# Again, we ignore int32 vs. int64
values = values.view("uint64")
if copy:
values = values.copy()
return values
elif (
is_datetime_or_timedelta_dtype(dtype)
and not is_dtype_equal(self.dtype, dtype)
) or is_float_dtype(dtype):
# disallow conversion between datetime/timedelta,
# and conversions for any datetimelike to float
msg = f"Cannot cast {type(self).__name__} to dtype {dtype}"
raise TypeError(msg)
elif is_categorical_dtype(dtype):
arr_cls = dtype.construct_array_type()
return arr_cls(self, dtype=dtype)
else:
return np.asarray(self, dtype=dtype)
def view(self, dtype=None):
if dtype is None or dtype is self.dtype:
return type(self)(self._data, dtype=self.dtype)
return self._data.view(dtype=dtype)
# ------------------------------------------------------------------
# ExtensionArray Interface
def unique(self):
result = unique1d(self.asi8)
return type(self)(result, dtype=self.dtype)
@classmethod
def _concat_same_type(cls, to_concat, axis: int = 0):
# do not pass tz to set because tzlocal cannot be hashed
dtypes = {str(x.dtype) for x in to_concat}
if len(dtypes) != 1:
raise ValueError("to_concat must have the same dtype (tz)", dtypes)
obj = to_concat[0]
dtype = obj.dtype
i8values = [x.asi8 for x in to_concat]
values = np.concatenate(i8values, axis=axis)
new_freq = None
if is_period_dtype(dtype):
new_freq = obj.freq
elif axis == 0:
# GH 3232: If the concat result is evenly spaced, we can retain the
# original frequency
to_concat = [x for x in to_concat if len(x)]
if obj.freq is not None and all(x.freq == obj.freq for x in to_concat):
pairs = zip(to_concat[:-1], to_concat[1:])
if all(pair[0][-1] + obj.freq == pair[1][0] for pair in pairs):
new_freq = obj.freq
return cls._simple_new(values, dtype=dtype, freq=new_freq)
def copy(self):
values = self.asi8.copy()
return type(self)._simple_new(values, dtype=self.dtype, freq=self.freq)
def _values_for_factorize(self):
return self.asi8, iNaT
@classmethod
def _from_factorized(cls, values, original):
return cls(values, dtype=original.dtype)
def _values_for_argsort(self):
return self._data
@Appender(ExtensionArray.shift.__doc__)
def shift(self, periods=1, fill_value=None, axis=0):
if not self.size or periods == 0:
return self.copy()
fill_value = self._validate_shift_value(fill_value)
new_values = shift(self._data, periods, axis, fill_value)
return type(self)._simple_new(new_values, dtype=self.dtype)
# ------------------------------------------------------------------
# Validation Methods
# TODO: try to de-duplicate these, ensure identical behavior
def _validate_fill_value(self, fill_value):
"""
If a fill_value is passed to `take` convert it to an i8 representation,
raising ValueError if this is not possible.
Parameters
----------
fill_value : object
Returns
-------
fill_value : np.int64
Raises
------
ValueError
"""
if is_valid_nat_for_dtype(fill_value, self.dtype):
fill_value = iNaT
elif isinstance(fill_value, self._recognized_scalars):
self._check_compatible_with(fill_value)
fill_value = self._scalar_type(fill_value)
fill_value = self._unbox_scalar(fill_value)
else:
raise ValueError(
f"'fill_value' should be a {self._scalar_type}. "
f"Got '{str(fill_value)}'."
)
return fill_value
def _validate_shift_value(self, fill_value):
# TODO(2.0): once this deprecation is enforced, used _validate_fill_value
if is_valid_nat_for_dtype(fill_value, self.dtype):
fill_value = NaT
elif not isinstance(fill_value, self._recognized_scalars):
# only warn if we're not going to raise
if self._scalar_type is Period and lib.is_integer(fill_value):
# kludge for #31971 since Period(integer) tries to cast to str
new_fill = Period._from_ordinal(fill_value, freq=self.freq)
else:
new_fill = self._scalar_type(fill_value)
# stacklevel here is chosen to be correct when called from
# DataFrame.shift or Series.shift
warnings.warn(
f"Passing {type(fill_value)} to shift is deprecated and "
"will raise in a future version, pass "
f"{self._scalar_type.__name__} instead.",
FutureWarning,
stacklevel=10,
)
fill_value = new_fill
fill_value = self._unbox_scalar(fill_value)
return fill_value
def _validate_searchsorted_value(self, value):
if isinstance(value, str):
try:
value = self._scalar_from_string(value)
except ValueError as err:
raise TypeError(
"searchsorted requires compatible dtype or scalar"
) from err
elif is_valid_nat_for_dtype(value, self.dtype):
value = NaT
elif isinstance(value, self._recognized_scalars):
value = self._scalar_type(value)
elif is_list_like(value) and not isinstance(value, type(self)):
value = array(value)
if not type(self)._is_recognized_dtype(value):
raise TypeError(
"searchsorted requires compatible dtype or scalar, "
f"not {type(value).__name__}"
)
if not (isinstance(value, (self._scalar_type, type(self))) or (value is NaT)):
raise TypeError(f"Unexpected type for 'value': {type(value)}")
if isinstance(value, type(self)):
self._check_compatible_with(value)
value = value.asi8
else:
value = self._unbox_scalar(value)
return value
def _validate_setitem_value(self, value):
if lib.is_scalar(value) and not isna(value):
value = com.maybe_box_datetimelike(value)
if is_list_like(value):
value = type(self)._from_sequence(value, dtype=self.dtype)
self._check_compatible_with(value, setitem=True)
value = value.asi8
elif isinstance(value, self._scalar_type):
self._check_compatible_with(value, setitem=True)
value = self._unbox_scalar(value)
elif is_valid_nat_for_dtype(value, self.dtype):
value = iNaT
else:
msg = (
f"'value' should be a '{self._scalar_type.__name__}', 'NaT', "
f"or array of those. Got '{type(value).__name__}' instead."
)
raise TypeError(msg)
return value
def _validate_insert_value(self, value):
if isinstance(value, self._recognized_scalars):
value = self._scalar_type(value)
self._check_compatible_with(value, setitem=True)
# TODO: if we dont have compat, should we raise or astype(object)?
# PeriodIndex does astype(object)
elif is_valid_nat_for_dtype(value, self.dtype):
# GH#18295
value = NaT
else:
raise TypeError(
f"cannot insert {type(self).__name__} with incompatible label"
)
return value
def _validate_where_value(self, other):
if is_valid_nat_for_dtype(other, self.dtype):
other = NaT
elif isinstance(other, self._recognized_scalars):
other = self._scalar_type(other)
self._check_compatible_with(other, setitem=True)
elif not is_list_like(other):
raise TypeError(f"Where requires matching dtype, not {type(other)}")
else:
# Do type inference if necessary up front
# e.g. we passed PeriodIndex.values and got an ndarray of Periods
other = array(other)
other = extract_array(other, extract_numpy=True)
if is_categorical_dtype(other.dtype):
# e.g. we have a Categorical holding self.dtype
if is_dtype_equal(other.categories.dtype, self.dtype):
other = other._internal_get_values()
if not type(self)._is_recognized_dtype(other.dtype):
raise TypeError(f"Where requires matching dtype, not {other.dtype}")
self._check_compatible_with(other, setitem=True)
if lib.is_scalar(other):
other = self._unbox_scalar(other)
else:
other = other.view("i8")
return other
# ------------------------------------------------------------------
# Additional array methods
# These are not part of the EA API, but we implement them because
# pandas assumes they're there.
def searchsorted(self, value, side="left", sorter=None):
"""
Find indices where elements should be inserted to maintain order.
Find the indices into a sorted array `self` such that, if the
corresponding elements in `value` were inserted before the indices,
the order of `self` would be preserved.
Parameters
----------
value : array_like
Values to insert into `self`.
side : {'left', 'right'}, optional
If 'left', the index of the first suitable location found is given.
If 'right', return the last such index. If there is no suitable
index, return either 0 or N (where N is the length of `self`).
sorter : 1-D array_like, optional
Optional array of integer indices that sort `self` into ascending
order. They are typically the result of ``np.argsort``.
Returns
-------
indices : array of ints
Array of insertion points with the same shape as `value`.
"""
value = self._validate_searchsorted_value(value)
# TODO: Use datetime64 semantics for sorting, xref GH#29844
return self.asi8.searchsorted(value, side=side, sorter=sorter)
def repeat(self, repeats, *args, **kwargs):
"""
Repeat elements of an array.
See Also
--------
numpy.ndarray.repeat
"""
nv.validate_repeat(args, kwargs)
values = self._data.repeat(repeats)
return type(self)(values.view("i8"), dtype=self.dtype)
def value_counts(self, dropna=False):
"""
Return a Series containing counts of unique values.
Parameters
----------
dropna : bool, default True
Don't include counts of NaT values.
Returns
-------
Series
"""
from pandas import Series, Index
if dropna:
values = self[~self.isna()]._data
else:
values = self._data
cls = type(self)
result = value_counts(values, sort=False, dropna=dropna)
index = Index(
cls(result.index.view("i8"), dtype=self.dtype), name=result.index.name
)
return Series(result._values, index=index, name=result.name)
def map(self, mapper):
# TODO(GH-23179): Add ExtensionArray.map
# Need to figure out if we want ExtensionArray.map first.
# If so, then we can refactor IndexOpsMixin._map_values to
# a standalone function and call from here..
# Else, just rewrite _map_infer_values to do the right thing.
from pandas import Index
return Index(self).map(mapper).array
# ------------------------------------------------------------------
# Null Handling
def isna(self):
return self._isnan
@property # NB: override with cache_readonly in immutable subclasses
def _isnan(self):
"""
return if each value is nan
"""
return self.asi8 == iNaT
@property # NB: override with cache_readonly in immutable subclasses
def _hasnans(self):
"""
return if I have any nans; enables various perf speedups
"""
return bool(self._isnan.any())
def _maybe_mask_results(self, result, fill_value=iNaT, convert=None):
"""
Parameters
----------
result : a ndarray
fill_value : object, default iNaT
convert : str, dtype or None
Returns
-------
result : ndarray with values replace by the fill_value
mask the result if needed, convert to the provided dtype if its not
None
This is an internal routine.
"""
if self._hasnans:
if convert:
result = result.astype(convert)
if fill_value is None:
fill_value = np.nan
result[self._isnan] = fill_value
return result
def fillna(self, value=None, method=None, limit=None):
# TODO(GH-20300): remove this
# Just overriding to ensure that we avoid an astype(object).
# Either 20300 or a `_values_for_fillna` would avoid this duplication.
if isinstance(value, ABCSeries):
value = value.array
value, method = validate_fillna_kwargs(value, method)
mask = self.isna()
if is_array_like(value):
if len(value) != len(self):
raise ValueError(
f"Length of 'value' does not match. Got ({len(value)}) "
f" expected {len(self)}"
)
value = value[mask]
if mask.any():
if method is not None:
if method == "pad":
func = missing.pad_1d
else:
func = missing.backfill_1d
values = self._data
if not is_period_dtype(self):
# For PeriodArray self._data is i8, which gets copied
# by `func`. Otherwise we need to make a copy manually
# to avoid modifying `self` in-place.
values = values.copy()
new_values = func(values, limit=limit, mask=mask)
if is_datetime64tz_dtype(self):
# we need to pass int64 values to the constructor to avoid
# re-localizing incorrectly
new_values = new_values.view("i8")
new_values = type(self)(new_values, dtype=self.dtype)
else:
# fill with value
new_values = self.copy()
new_values[mask] = value
else:
new_values = self.copy()
return new_values
# ------------------------------------------------------------------
# Frequency Properties/Methods
@property
def freq(self):
"""
Return the frequency object if it is set, otherwise None.
"""
return self._freq
@freq.setter
def freq(self, value):
if value is not None:
value = frequencies.to_offset(value)
self._validate_frequency(self, value)
self._freq = value
@property
def freqstr(self):
"""
Return the frequency object as a string if its set, otherwise None.
"""
if self.freq is None:
return None
return self.freq.freqstr
@property # NB: override with cache_readonly in immutable subclasses
def inferred_freq(self):
"""
Tryies to return a string representing a frequency guess,
generated by infer_freq. Returns None if it can't autodetect the
frequency.
"""
if self.ndim != 1:
return None
try:
return frequencies.infer_freq(self)
except ValueError:
return None
@property # NB: override with cache_readonly in immutable subclasses
def _resolution(self):
return frequencies.Resolution.get_reso_from_freq(self.freqstr)
@property # NB: override with cache_readonly in immutable subclasses
def resolution(self):
"""
Returns day, hour, minute, second, millisecond or microsecond
"""
return frequencies.Resolution.get_str(self._resolution)
@classmethod
def _validate_frequency(cls, index, freq, **kwargs):
"""
Validate that a frequency is compatible with the values of a given
Datetime Array/Index or Timedelta Array/Index
Parameters
----------
index : DatetimeIndex or TimedeltaIndex
The index on which to determine if the given frequency is valid
freq : DateOffset
The frequency to validate
"""
if is_period_dtype(cls):
# Frequency validation is not meaningful for Period Array/Index
return None
inferred = index.inferred_freq
if index.size == 0 or inferred == freq.freqstr:
return None
try:
on_freq = cls._generate_range(
start=index[0], end=None, periods=len(index), freq=freq, **kwargs
)
if not np.array_equal(index.asi8, on_freq.asi8):
raise ValueError
except ValueError as e:
if "non-fixed" in str(e):
# non-fixed frequencies are not meaningful for timedelta64;
# we retain that error message
raise e
# GH#11587 the main way this is reached is if the `np.array_equal`
# check above is False. This can also be reached if index[0]
# is `NaT`, in which case the call to `cls._generate_range` will
# raise a ValueError, which we re-raise with a more targeted
# message.
raise ValueError(
f"Inferred frequency {inferred} from passed values "
f"does not conform to passed frequency {freq.freqstr}"
) from e
# monotonicity/uniqueness properties are called via frequencies.infer_freq,
# see GH#23789
@property
def _is_monotonic_increasing(self):
return algos.is_monotonic(self.asi8, timelike=True)[0]
@property
def _is_monotonic_decreasing(self):
return algos.is_monotonic(self.asi8, timelike=True)[1]
@property
def _is_unique(self):
return len(unique1d(self.asi8)) == len(self)
# ------------------------------------------------------------------
# Arithmetic Methods
_create_comparison_method = classmethod(_datetimelike_array_cmp)
# pow is invalid for all three subclasses; TimedeltaArray will override
# the multiplication and division ops
__pow__ = make_invalid_op("__pow__")
__rpow__ = make_invalid_op("__rpow__")
__mul__ = make_invalid_op("__mul__")
__rmul__ = make_invalid_op("__rmul__")
__truediv__ = make_invalid_op("__truediv__")
__rtruediv__ = make_invalid_op("__rtruediv__")
__floordiv__ = make_invalid_op("__floordiv__")
__rfloordiv__ = make_invalid_op("__rfloordiv__")
__mod__ = make_invalid_op("__mod__")
__rmod__ = make_invalid_op("__rmod__")
__divmod__ = make_invalid_op("__divmod__")
__rdivmod__ = make_invalid_op("__rdivmod__")
def _add_datetimelike_scalar(self, other):
# Overridden by TimedeltaArray
raise TypeError(f"cannot add {type(self).__name__} and {type(other).__name__}")
_add_datetime_arraylike = _add_datetimelike_scalar
def _sub_datetimelike_scalar(self, other):
# Overridden by DatetimeArray
assert other is not NaT
raise TypeError(f"cannot subtract a datelike from a {type(self).__name__}")
_sub_datetime_arraylike = _sub_datetimelike_scalar
def _sub_period(self, other):
# Overridden by PeriodArray
raise TypeError(f"cannot subtract Period from a {type(self).__name__}")
def _add_offset(self, offset):
raise AbstractMethodError(self)
def _add_timedeltalike_scalar(self, other):
"""
Add a delta of a timedeltalike
Returns
-------
Same type as self
"""
if isna(other):
# i.e np.timedelta64("NaT"), not recognized by delta_to_nanoseconds
new_values = np.empty(self.shape, dtype="i8")
new_values[:] = iNaT
return type(self)(new_values, dtype=self.dtype)
inc = delta_to_nanoseconds(other)
new_values = checked_add_with_arr(self.asi8, inc, arr_mask=self._isnan).view(
"i8"
)
new_values = self._maybe_mask_results(new_values)
new_freq = None
if isinstance(self.freq, Tick) or is_period_dtype(self.dtype):
# adding a scalar preserves freq
new_freq = self.freq
return type(self)(new_values, dtype=self.dtype, freq=new_freq)
def _add_timedelta_arraylike(self, other):
"""
Add a delta of a TimedeltaIndex
Returns
-------
Same type as self
"""
# overridden by PeriodArray
if len(self) != len(other):
raise ValueError("cannot add indices of unequal length")
if isinstance(other, np.ndarray):
# ndarray[timedelta64]; wrap in TimedeltaIndex for op
from pandas.core.arrays import TimedeltaArray
other = TimedeltaArray._from_sequence(other)
self_i8 = self.asi8
other_i8 = other.asi8
new_values = checked_add_with_arr(
self_i8, other_i8, arr_mask=self._isnan, b_mask=other._isnan
)
if self._hasnans or other._hasnans:
mask = (self._isnan) | (other._isnan)
new_values[mask] = iNaT
return type(self)(new_values, dtype=self.dtype)
def _add_nat(self):
"""
Add pd.NaT to self
"""
if is_period_dtype(self):
raise TypeError(
f"Cannot add {type(self).__name__} and {type(NaT).__name__}"
)
# GH#19124 pd.NaT is treated like a timedelta for both timedelta
# and datetime dtypes
result = np.zeros(self.shape, dtype=np.int64)
result.fill(iNaT)
return type(self)(result, dtype=self.dtype, freq=None)
def _sub_nat(self):
"""
Subtract pd.NaT from self
"""
# GH#19124 Timedelta - datetime is not in general well-defined.
# We make an exception for pd.NaT, which in this case quacks
# like a timedelta.
# For datetime64 dtypes by convention we treat NaT as a datetime, so
# this subtraction returns a timedelta64 dtype.
# For period dtype, timedelta64 is a close-enough return dtype.
result = np.zeros(self.shape, dtype=np.int64)
result.fill(iNaT)
return result.view("timedelta64[ns]")
def _sub_period_array(self, other):
"""
Subtract a Period Array/Index from self. This is only valid if self
is itself a Period Array/Index, raises otherwise. Both objects must
have the same frequency.
Parameters
----------
other : PeriodIndex or PeriodArray
Returns
-------
result : np.ndarray[object]
Array of DateOffset objects; nulls represented by NaT.
"""
if not is_period_dtype(self):
raise TypeError(
f"cannot subtract {other.dtype}-dtype from {type(self).__name__}"
)
if self.freq != other.freq:
msg = DIFFERENT_FREQ.format(
cls=type(self).__name__, own_freq=self.freqstr, other_freq=other.freqstr
)
raise IncompatibleFrequency(msg)
new_values = checked_add_with_arr(
self.asi8, -other.asi8, arr_mask=self._isnan, b_mask=other._isnan
)
new_values = np.array([self.freq.base * x for x in new_values])
if self._hasnans or other._hasnans:
mask = (self._isnan) | (other._isnan)
new_values[mask] = NaT
return new_values
def _addsub_object_array(self, other: np.ndarray, op):
"""
Add or subtract array-like of DateOffset objects
Parameters
----------
other : np.ndarray[object]
op : {operator.add, operator.sub}
Returns
-------
result : same class as self
"""
assert op in [operator.add, operator.sub]
if len(other) == 1:
return op(self, other[0])
warnings.warn(
"Adding/subtracting array of DateOffsets to "
f"{type(self).__name__} not vectorized",
PerformanceWarning,
)
# Caller is responsible for broadcasting if necessary
assert self.shape == other.shape, (self.shape, other.shape)
res_values = op(self.astype("O"), np.array(other))
result = array(res_values.ravel())
result = extract_array(result, extract_numpy=True).reshape(self.shape)
return result
def _time_shift(self, periods, freq=None):
"""
Shift each value by `periods`.
Note this is different from ExtensionArray.shift, which
shifts the *position* of each element, padding the end with
missing values.
Parameters
----------
periods : int
Number of periods to shift by.
freq : pandas.DateOffset, pandas.Timedelta, or str
Frequency increment to shift by.
"""
if freq is not None and freq != self.freq:
if isinstance(freq, str):
freq = frequencies.to_offset(freq)
offset = periods * freq
result = self + offset
return result
if periods == 0:
# immutable so OK
return self.copy()
if self.freq is None:
raise NullFrequencyError("Cannot shift with no freq")
start = self[0] + periods * self.freq
end = self[-1] + periods * self.freq
# Note: in the DatetimeTZ case, _generate_range will infer the
# appropriate timezone from `start` and `end`, so tz does not need
# to be passed explicitly.
return self._generate_range(start=start, end=end, periods=None, freq=self.freq)
@unpack_zerodim_and_defer("__add__")
def __add__(self, other):
# scalar others
if other is NaT:
result = self._add_nat()
elif isinstance(other, (Tick, timedelta, np.timedelta64)):
result = self._add_timedeltalike_scalar(other)
elif isinstance(other, DateOffset):
# specifically _not_ a Tick
result = self._add_offset(other)
elif isinstance(other, (datetime, np.datetime64)):
result = self._add_datetimelike_scalar(other)
elif lib.is_integer(other):
# This check must come after the check for np.timedelta64
# as is_integer returns True for these
if not is_period_dtype(self):
raise integer_op_not_supported(self)
result = self._time_shift(other)
# array-like others
elif is_timedelta64_dtype(other):
# TimedeltaIndex, ndarray[timedelta64]
result = self._add_timedelta_arraylike(other)
elif is_object_dtype(other):
# e.g. Array/Index of DateOffset objects
result = self._addsub_object_array(other, operator.add)
elif is_datetime64_dtype(other) or is_datetime64tz_dtype(other):
# DatetimeIndex, ndarray[datetime64]
return self._add_datetime_arraylike(other)
elif is_integer_dtype(other):
if not is_period_dtype(self):
raise integer_op_not_supported(self)
result = self._addsub_int_array(other, operator.add)
else:
# Includes Categorical, other ExtensionArrays
# For PeriodDtype, if self is a TimedeltaArray and other is a
# PeriodArray with a timedelta-like (i.e. Tick) freq, this
# operation is valid. Defer to the PeriodArray implementation.
# In remaining cases, this will end up raising TypeError.
return NotImplemented
if is_timedelta64_dtype(result) and isinstance(result, np.ndarray):
from pandas.core.arrays import TimedeltaArray
return TimedeltaArray(result)
return result
def __radd__(self, other):
# alias for __add__
return self.__add__(other)
@unpack_zerodim_and_defer("__sub__")
def __sub__(self, other):
# scalar others
if other is NaT:
result = self._sub_nat()
elif isinstance(other, (Tick, timedelta, np.timedelta64)):
result = self._add_timedeltalike_scalar(-other)
elif isinstance(other, DateOffset):
# specifically _not_ a Tick
result = self._add_offset(-other)
elif isinstance(other, (datetime, np.datetime64)):
result = self._sub_datetimelike_scalar(other)
elif lib.is_integer(other):
# This check must come after the check for np.timedelta64
# as is_integer returns True for these
if not is_period_dtype(self):
raise integer_op_not_supported(self)
result = self._time_shift(-other)
elif isinstance(other, Period):
result = self._sub_period(other)
# array-like others
elif is_timedelta64_dtype(other):
# TimedeltaIndex, ndarray[timedelta64]
result = self._add_timedelta_arraylike(-other)
elif is_object_dtype(other):
# e.g. Array/Index of DateOffset objects
result = self._addsub_object_array(other, operator.sub)
elif is_datetime64_dtype(other) or is_datetime64tz_dtype(other):
# DatetimeIndex, ndarray[datetime64]
result = self._sub_datetime_arraylike(other)
elif is_period_dtype(other):
# PeriodIndex
result = self._sub_period_array(other)
elif is_integer_dtype(other):
if not is_period_dtype(self):
raise integer_op_not_supported(self)
result = self._addsub_int_array(other, operator.sub)
else:
# Includes ExtensionArrays, float_dtype
return NotImplemented
if is_timedelta64_dtype(result) and isinstance(result, np.ndarray):
from pandas.core.arrays import TimedeltaArray
return TimedeltaArray(result)
return result
def __rsub__(self, other):
if is_datetime64_any_dtype(other) and is_timedelta64_dtype(self.dtype):
# ndarray[datetime64] cannot be subtracted from self, so
# we need to wrap in DatetimeArray/Index and flip the operation
if lib.is_scalar(other):
# i.e. np.datetime64 object
return Timestamp(other) - self
if not isinstance(other, DatetimeLikeArrayMixin):
# Avoid down-casting DatetimeIndex
from pandas.core.arrays import DatetimeArray
other = DatetimeArray(other)
return other - self
elif (
is_datetime64_any_dtype(self.dtype)
and hasattr(other, "dtype")
and not is_datetime64_any_dtype(other.dtype)
):
# GH#19959 datetime - datetime is well-defined as timedelta,
# but any other type - datetime is not well-defined.
raise TypeError(
f"cannot subtract {type(self).__name__} from {type(other).__name__}"
)
elif is_period_dtype(self.dtype) and is_timedelta64_dtype(other):
# TODO: Can we simplify/generalize these cases at all?
raise TypeError(f"cannot subtract {type(self).__name__} from {other.dtype}")
elif is_timedelta64_dtype(self.dtype):
if lib.is_integer(other) or is_integer_dtype(other):
# need to subtract before negating, since that flips freq
# -self flips self.freq, messing up results
return -(self - other)
return (-self) + other
return -(self - other)
def __iadd__(self, other):
result = self + other
self[:] = result[:]
if not is_period_dtype(self):
# restore freq, which is invalidated by setitem
self._freq = result._freq
return self
def __isub__(self, other):
result = self - other
self[:] = result[:]
if not is_period_dtype(self):
# restore freq, which is invalidated by setitem
self._freq = result._freq
return self
# --------------------------------------------------------------
# Reductions
def _reduce(self, name, axis=0, skipna=True, **kwargs):
op = getattr(self, name, None)
if op:
return op(skipna=skipna, **kwargs)
else:
return super()._reduce(name, skipna, **kwargs)
def min(self, axis=None, skipna=True, *args, **kwargs):
"""
Return the minimum value of the Array or minimum along
an axis.
See Also
--------
numpy.ndarray.min
Index.min : Return the minimum value in an Index.
Series.min : Return the minimum value in a Series.
"""
nv.validate_min(args, kwargs)
nv.validate_minmax_axis(axis)
result = nanops.nanmin(self.asi8, skipna=skipna, mask=self.isna())
if isna(result):
# Period._from_ordinal does not handle np.nan gracefully
return NaT
return self._box_func(result)
def max(self, axis=None, skipna=True, *args, **kwargs):
"""
Return the maximum value of the Array or maximum along
an axis.
See Also
--------
numpy.ndarray.max
Index.max : Return the maximum value in an Index.
Series.max : Return the maximum value in a Series.
"""
# TODO: skipna is broken with max.
# See https://github.com/pandas-dev/pandas/issues/24265
nv.validate_max(args, kwargs)
nv.validate_minmax_axis(axis)
mask = self.isna()
if skipna:
values = self[~mask].asi8
elif mask.any():
return NaT
else:
values = self.asi8
if not len(values):
# short-circuit for empty max / min
return NaT
result = nanops.nanmax(values, skipna=skipna)
# Don't have to worry about NA `result`, since no NA went in.
return self._box_func(result)
def mean(self, skipna=True):
"""
Return the mean value of the Array.
.. versionadded:: 0.25.0
Parameters
----------
skipna : bool, default True
Whether to ignore any NaT elements.
Returns
-------
scalar
Timestamp or Timedelta.
See Also
--------
numpy.ndarray.mean : Returns the average of array elements along a given axis.
Series.mean : Return the mean value in a Series.
Notes
-----
mean is only defined for Datetime and Timedelta dtypes, not for Period.
"""
if is_period_dtype(self):
# See discussion in GH#24757
raise TypeError(
f"mean is not implemented for {type(self).__name__} since the "
"meaning is ambiguous. An alternative is "
"obj.to_timestamp(how='start').mean()"
)
mask = self.isna()
if skipna:
values = self[~mask]
elif mask.any():
return NaT
else:
values = self
if not len(values):
# short-circuit for empty max / min
return NaT
result = nanops.nanmean(values.view("i8"), skipna=skipna)
# Don't have to worry about NA `result`, since no NA went in.
return self._box_func(result)
DatetimeLikeArrayMixin._add_comparison_ops()
# -------------------------------------------------------------------
# Shared Constructor Helpers
def validate_periods(periods):
"""
If a `periods` argument is passed to the Datetime/Timedelta Array/Index
constructor, cast it to an integer.
Parameters
----------
periods : None, float, int
Returns
-------
periods : None or int
Raises
------
TypeError
if periods is None, float, or int
"""
if periods is not None:
if lib.is_float(periods):
periods = int(periods)
elif not lib.is_integer(periods):
raise TypeError(f"periods must be a number, got {periods}")
return periods
def validate_endpoints(closed):
"""
Check that the `closed` argument is among [None, "left", "right"]
Parameters
----------
closed : {None, "left", "right"}
Returns
-------
left_closed : bool
right_closed : bool
Raises
------
ValueError : if argument is not among valid values
"""
left_closed = False
right_closed = False
if closed is None:
left_closed = True
right_closed = True
elif closed == "left":
left_closed = True
elif closed == "right":
right_closed = True
else:
raise ValueError("Closed has to be either 'left', 'right' or None")
return left_closed, right_closed
def validate_inferred_freq(freq, inferred_freq, freq_infer):
"""
If the user passes a freq and another freq is inferred from passed data,
require that they match.
Parameters
----------
freq : DateOffset or None
inferred_freq : DateOffset or None
freq_infer : bool
Returns
-------
freq : DateOffset or None
freq_infer : bool
Notes
-----
We assume at this point that `maybe_infer_freq` has been called, so
`freq` is either a DateOffset object or None.
"""
if inferred_freq is not None:
if freq is not None and freq != inferred_freq:
raise ValueError(
f"Inferred frequency {inferred_freq} from passed "
"values does not conform to passed frequency "
f"{freq.freqstr}"
)
elif freq is None:
freq = inferred_freq
freq_infer = False
return freq, freq_infer
def maybe_infer_freq(freq):
"""
Comparing a DateOffset to the string "infer" raises, so we need to
be careful about comparisons. Make a dummy variable `freq_infer` to
signify the case where the given freq is "infer" and set freq to None
to avoid comparison trouble later on.
Parameters
----------
freq : {DateOffset, None, str}
Returns
-------
freq : {DateOffset, None}
freq_infer : bool
Whether we should inherit the freq of passed data.
"""
freq_infer = False
if not isinstance(freq, DateOffset):
# if a passed freq is None, don't infer automatically
if freq != "infer":
freq = frequencies.to_offset(freq)
else:
freq_infer = True
freq = None
return freq, freq_infer
| BugsInPy/BugsInPy/temp/projects/pandas/bug-17-fixed/pandas/pandas/core/arrays/datetimelike.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-17-buggy/pandas/pandas/core/arrays/datetimelike.py |
pandas-bug-53 | from datetime import datetime
import operator
from textwrap import dedent
from typing import TYPE_CHECKING, Any, FrozenSet, Hashable, Optional, Union
import warnings
import numpy as np
from pandas._libs import algos as libalgos, index as libindex, lib
import pandas._libs.join as libjoin
from pandas._libs.lib import is_datetime_array
from pandas._libs.tslibs import OutOfBoundsDatetime, Timestamp
from pandas._libs.tslibs.period import IncompatibleFrequency
from pandas._libs.tslibs.timezones import tz_compare
from pandas._typing import Label
from pandas.compat import set_function_name
from pandas.compat.numpy import function as nv
from pandas.util._decorators import Appender, Substitution, cache_readonly
from pandas.core.dtypes import concat as _concat
from pandas.core.dtypes.cast import (
maybe_cast_to_integer_array,
validate_numeric_casting,
)
from pandas.core.dtypes.common import (
ensure_categorical,
ensure_int64,
ensure_object,
ensure_platform_int,
is_bool,
is_bool_dtype,
is_categorical,
is_categorical_dtype,
is_datetime64_any_dtype,
is_datetime64tz_dtype,
is_dtype_equal,
is_extension_array_dtype,
is_float,
is_float_dtype,
is_hashable,
is_integer,
is_integer_dtype,
is_interval_dtype,
is_iterator,
is_list_like,
is_object_dtype,
is_period_dtype,
is_scalar,
is_signed_integer_dtype,
is_timedelta64_dtype,
is_unsigned_integer_dtype,
)
from pandas.core.dtypes.concat import concat_compat
from pandas.core.dtypes.generic import (
ABCCategorical,
ABCDataFrame,
ABCDatetimeIndex,
ABCIntervalIndex,
ABCMultiIndex,
ABCPandasArray,
ABCPeriodIndex,
ABCRangeIndex,
ABCSeries,
ABCTimedeltaIndex,
)
from pandas.core.dtypes.missing import array_equivalent, isna
from pandas.core import ops
from pandas.core.accessor import CachedAccessor
import pandas.core.algorithms as algos
from pandas.core.arrays import ExtensionArray
from pandas.core.base import IndexOpsMixin, PandasObject
import pandas.core.common as com
from pandas.core.indexers import deprecate_ndim_indexing
from pandas.core.indexes.frozen import FrozenList
import pandas.core.missing as missing
from pandas.core.ops import get_op_result_name
from pandas.core.ops.invalid import make_invalid_op
from pandas.core.strings import StringMethods
from pandas.io.formats.printing import (
PrettyDict,
default_pprint,
format_object_attrs,
format_object_summary,
pprint_thing,
)
if TYPE_CHECKING:
from pandas import Series
__all__ = ["Index"]
_unsortable_types = frozenset(("mixed", "mixed-integer"))
_index_doc_kwargs = dict(
klass="Index",
inplace="",
target_klass="Index",
raises_section="",
unique="Index",
duplicated="np.ndarray",
)
_index_shared_docs = dict()
str_t = str
def _make_comparison_op(op, cls):
def cmp_method(self, other):
if isinstance(other, (np.ndarray, Index, ABCSeries, ExtensionArray)):
if other.ndim > 0 and len(self) != len(other):
raise ValueError("Lengths must match to compare")
if is_object_dtype(self) and isinstance(other, ABCCategorical):
left = type(other)(self._values, dtype=other.dtype)
return op(left, other)
elif is_object_dtype(self) and isinstance(other, ExtensionArray):
# e.g. PeriodArray
with np.errstate(all="ignore"):
result = op(self.values, other)
elif is_object_dtype(self) and not isinstance(self, ABCMultiIndex):
# don't pass MultiIndex
with np.errstate(all="ignore"):
result = ops.comp_method_OBJECT_ARRAY(op, self.values, other)
else:
with np.errstate(all="ignore"):
result = op(self.values, np.asarray(other))
if is_bool_dtype(result):
return result
return ops.invalid_comparison(self, other, op)
name = f"__{op.__name__}__"
return set_function_name(cmp_method, name, cls)
def _make_arithmetic_op(op, cls):
def index_arithmetic_method(self, other):
if isinstance(other, (ABCSeries, ABCDataFrame, ABCTimedeltaIndex)):
return NotImplemented
from pandas import Series
result = op(Series(self), other)
if isinstance(result, tuple):
return (Index(result[0]), Index(result[1]))
return Index(result)
name = f"__{op.__name__}__"
# TODO: docstring?
return set_function_name(index_arithmetic_method, name, cls)
class InvalidIndexError(Exception):
pass
_o_dtype = np.dtype(object)
_Identity = object
def _new_Index(cls, d):
"""
This is called upon unpickling, rather than the default which doesn't
have arguments and breaks __new__.
"""
# required for backward compat, because PI can't be instantiated with
# ordinals through __new__ GH #13277
if issubclass(cls, ABCPeriodIndex):
from pandas.core.indexes.period import _new_PeriodIndex
return _new_PeriodIndex(cls, **d)
if issubclass(cls, ABCMultiIndex):
if "labels" in d and "codes" not in d:
# GH#23752 "labels" kwarg has been replaced with "codes"
d["codes"] = d.pop("labels")
return cls.__new__(cls, **d)
class Index(IndexOpsMixin, PandasObject):
"""
Immutable ndarray implementing an ordered, sliceable set. The basic object
storing axis labels for all pandas objects.
Parameters
----------
data : array-like (1-dimensional)
dtype : NumPy dtype (default: object)
If dtype is None, we find the dtype that best fits the data.
If an actual dtype is provided, we coerce to that dtype if it's safe.
Otherwise, an error will be raised.
copy : bool
Make a copy of input ndarray.
name : object
Name to be stored in the index.
tupleize_cols : bool (default: True)
When True, attempt to create a MultiIndex if possible.
See Also
--------
RangeIndex : Index implementing a monotonic integer range.
CategoricalIndex : Index of :class:`Categorical` s.
MultiIndex : A multi-level, or hierarchical, Index.
IntervalIndex : An Index of :class:`Interval` s.
DatetimeIndex, TimedeltaIndex, PeriodIndex
Int64Index, UInt64Index, Float64Index
Notes
-----
An Index instance can **only** contain hashable objects
Examples
--------
>>> pd.Index([1, 2, 3])
Int64Index([1, 2, 3], dtype='int64')
>>> pd.Index(list('abc'))
Index(['a', 'b', 'c'], dtype='object')
"""
# tolist is not actually deprecated, just suppressed in the __dir__
_deprecations: FrozenSet[str] = (
PandasObject._deprecations
| IndexOpsMixin._deprecations
| frozenset(["contains", "set_value"])
)
# To hand over control to subclasses
_join_precedence = 1
# Cython methods; see github.com/cython/cython/issues/2647
# for why we need to wrap these instead of making them class attributes
# Moreover, cython will choose the appropriate-dtyped sub-function
# given the dtypes of the passed arguments
def _left_indexer_unique(self, left, right):
return libjoin.left_join_indexer_unique(left, right)
def _left_indexer(self, left, right):
return libjoin.left_join_indexer(left, right)
def _inner_indexer(self, left, right):
return libjoin.inner_join_indexer(left, right)
def _outer_indexer(self, left, right):
return libjoin.outer_join_indexer(left, right)
_typ = "index"
_data: Union[ExtensionArray, np.ndarray]
_id = None
_name: Label = None
# MultiIndex.levels previously allowed setting the index name. We
# don't allow this anymore, and raise if it happens rather than
# failing silently.
_no_setting_name: bool = False
_comparables = ["name"]
_attributes = ["name"]
_is_numeric_dtype = False
_can_hold_na = True
# would we like our indexing holder to defer to us
_defer_to_indexing = False
# prioritize current class for _shallow_copy_with_infer,
# used to infer integers as datetime-likes
_infer_as_myclass = False
_engine_type = libindex.ObjectEngine
# whether we support partial string indexing. Overridden
# in DatetimeIndex and PeriodIndex
_supports_partial_string_indexing = False
_accessors = {"str"}
str = CachedAccessor("str", StringMethods)
# --------------------------------------------------------------------
# Constructors
def __new__(
cls, data=None, dtype=None, copy=False, name=None, tupleize_cols=True, **kwargs,
) -> "Index":
from pandas.core.indexes.range import RangeIndex
name = maybe_extract_name(name, data, cls)
if isinstance(data, ABCPandasArray):
# ensure users don't accidentally put a PandasArray in an index.
data = data.to_numpy()
# range
if isinstance(data, RangeIndex):
return RangeIndex(start=data, copy=copy, dtype=dtype, name=name)
elif isinstance(data, range):
return RangeIndex.from_range(data, dtype=dtype, name=name)
# categorical
elif is_categorical_dtype(data) or is_categorical_dtype(dtype):
# Delay import for perf. https://github.com/pandas-dev/pandas/pull/31423
from pandas.core.indexes.category import CategoricalIndex
return CategoricalIndex(data, dtype=dtype, copy=copy, name=name, **kwargs)
# interval
elif is_interval_dtype(data) or is_interval_dtype(dtype):
# Delay import for perf. https://github.com/pandas-dev/pandas/pull/31423
from pandas.core.indexes.interval import IntervalIndex
return _maybe_asobject(dtype, IntervalIndex, data, copy, name, **kwargs)
elif (
is_datetime64_any_dtype(data)
or is_datetime64_any_dtype(dtype)
or "tz" in kwargs
):
# Delay import for perf. https://github.com/pandas-dev/pandas/pull/31423
from pandas import DatetimeIndex
return _maybe_asobject(dtype, DatetimeIndex, data, copy, name, **kwargs)
elif is_timedelta64_dtype(data) or is_timedelta64_dtype(dtype):
# Delay import for perf. https://github.com/pandas-dev/pandas/pull/31423
from pandas import TimedeltaIndex
return _maybe_asobject(dtype, TimedeltaIndex, data, copy, name, **kwargs)
elif is_period_dtype(data) or is_period_dtype(dtype):
# Delay import for perf. https://github.com/pandas-dev/pandas/pull/31423
from pandas import PeriodIndex
return _maybe_asobject(dtype, PeriodIndex, data, copy, name, **kwargs)
# extension dtype
elif is_extension_array_dtype(data) or is_extension_array_dtype(dtype):
if not (dtype is None or is_object_dtype(dtype)):
# coerce to the provided dtype
ea_cls = dtype.construct_array_type()
data = ea_cls._from_sequence(data, dtype=dtype, copy=False)
else:
data = np.asarray(data, dtype=object)
# coerce to the object dtype
data = data.astype(object)
return Index(data, dtype=object, copy=copy, name=name, **kwargs)
# index-like
elif isinstance(data, (np.ndarray, Index, ABCSeries)):
# Delay import for perf. https://github.com/pandas-dev/pandas/pull/31423
from pandas.core.indexes.numeric import (
Float64Index,
Int64Index,
UInt64Index,
)
if dtype is not None:
# we need to avoid having numpy coerce
# things that look like ints/floats to ints unless
# they are actually ints, e.g. '0' and 0.0
# should not be coerced
# GH 11836
data = _maybe_cast_with_dtype(data, dtype, copy)
dtype = data.dtype # TODO: maybe not for object?
# maybe coerce to a sub-class
if is_signed_integer_dtype(data.dtype):
return Int64Index(data, copy=copy, dtype=dtype, name=name)
elif is_unsigned_integer_dtype(data.dtype):
return UInt64Index(data, copy=copy, dtype=dtype, name=name)
elif is_float_dtype(data.dtype):
return Float64Index(data, copy=copy, dtype=dtype, name=name)
elif issubclass(data.dtype.type, np.bool) or is_bool_dtype(data):
subarr = data.astype("object")
else:
subarr = com.asarray_tuplesafe(data, dtype=object)
# asarray_tuplesafe does not always copy underlying data,
# so need to make sure that this happens
if copy:
subarr = subarr.copy()
if dtype is None:
new_data, new_dtype = _maybe_cast_data_without_dtype(subarr)
if new_dtype is not None:
return cls(
new_data, dtype=new_dtype, copy=False, name=name, **kwargs
)
if kwargs:
raise TypeError(f"Unexpected keyword arguments {repr(set(kwargs))}")
if subarr.ndim > 1:
# GH#13601, GH#20285, GH#27125
raise ValueError("Index data must be 1-dimensional")
return cls._simple_new(subarr, name)
elif hasattr(data, "__array__"):
return Index(np.asarray(data), dtype=dtype, copy=copy, name=name, **kwargs)
elif data is None or is_scalar(data):
raise cls._scalar_data_error(data)
else:
if tupleize_cols and is_list_like(data):
# GH21470: convert iterable to list before determining if empty
if is_iterator(data):
data = list(data)
if data and all(isinstance(e, tuple) for e in data):
# we must be all tuples, otherwise don't construct
# 10697
from pandas.core.indexes.multi import MultiIndex
return MultiIndex.from_tuples(
data, names=name or kwargs.get("names")
)
# other iterable of some kind
subarr = com.asarray_tuplesafe(data, dtype=object)
return Index(subarr, dtype=dtype, copy=copy, name=name, **kwargs)
"""
NOTE for new Index creation:
- _simple_new: It returns new Index with the same type as the caller.
All metadata (such as name) must be provided by caller's responsibility.
Using _shallow_copy is recommended because it fills these metadata
otherwise specified.
- _shallow_copy: It returns new Index with the same type (using
_simple_new), but fills caller's metadata otherwise specified. Passed
kwargs will overwrite corresponding metadata.
- _shallow_copy_with_infer: It returns new Index inferring its type
from passed values. It fills caller's metadata otherwise specified as the
same as _shallow_copy.
See each method's docstring.
"""
@property
def asi8(self):
"""
Integer representation of the values.
Returns
-------
ndarray
An ndarray with int64 dtype.
"""
return None
@classmethod
def _simple_new(cls, values, name=None, dtype=None):
"""
We require that we have a dtype compat for the values. If we are passed
a non-dtype compat, then coerce using the constructor.
Must be careful not to recurse.
"""
assert isinstance(values, np.ndarray), type(values)
result = object.__new__(cls)
result._data = values
# _index_data is a (temporary?) fix to ensure that the direct data
# manipulation we do in `_libs/reduction.pyx` continues to work.
# We need access to the actual ndarray, since we're messing with
# data buffers and strides. We don't re-use `_ndarray_values`, since
# we actually set this value too.
result._index_data = values
result._name = name
return result._reset_identity()
@cache_readonly
def _constructor(self):
return type(self)
# --------------------------------------------------------------------
# Index Internals Methods
def _get_attributes_dict(self):
"""
Return an attributes dict for my class.
"""
return {k: getattr(self, k, None) for k in self._attributes}
def _shallow_copy(self, values=None, **kwargs):
"""
Create a new Index with the same class as the caller, don't copy the
data, use the same object attributes with passed in attributes taking
precedence.
*this is an internal non-public method*
Parameters
----------
values : the values to create the new Index, optional
kwargs : updates the default attributes for this Index
"""
if values is None:
values = self.values
attributes = self._get_attributes_dict()
attributes.update(kwargs)
return self._simple_new(values, **attributes)
def _shallow_copy_with_infer(self, values, **kwargs):
"""
Create a new Index inferring the class with passed value, don't copy
the data, use the same object attributes with passed in attributes
taking precedence.
*this is an internal non-public method*
Parameters
----------
values : the values to create the new Index, optional
kwargs : updates the default attributes for this Index
"""
attributes = self._get_attributes_dict()
attributes.update(kwargs)
attributes["copy"] = False
if not len(values) and "dtype" not in kwargs:
# TODO: what if hasattr(values, "dtype")?
attributes["dtype"] = self.dtype
if self._infer_as_myclass:
try:
return self._constructor(values, **attributes)
except (TypeError, ValueError):
pass
return Index(values, **attributes)
def _update_inplace(self, result, **kwargs):
# guard when called from IndexOpsMixin
raise TypeError("Index can't be updated inplace")
def is_(self, other) -> bool:
"""
More flexible, faster check like ``is`` but that works through views.
Note: this is *not* the same as ``Index.identical()``, which checks
that metadata is also the same.
Parameters
----------
other : object
other object to compare against.
Returns
-------
True if both have same underlying data, False otherwise : bool
"""
# use something other than None to be clearer
return self._id is getattr(other, "_id", Ellipsis) and self._id is not None
def _reset_identity(self):
"""
Initializes or resets ``_id`` attribute with new object.
"""
self._id = _Identity()
return self
def _cleanup(self):
self._engine.clear_mapping()
@cache_readonly
def _engine(self):
# property, for now, slow to look up
# to avoid a reference cycle, bind `_ndarray_values` to a local variable, so
# `self` is not passed into the lambda.
_ndarray_values = self._ndarray_values
return self._engine_type(lambda: _ndarray_values, len(self))
# --------------------------------------------------------------------
# Array-Like Methods
# ndarray compat
def __len__(self) -> int:
"""
Return the length of the Index.
"""
return len(self._data)
def __array__(self, dtype=None) -> np.ndarray:
"""
The array interface, return my values.
"""
return np.asarray(self._data, dtype=dtype)
def __array_wrap__(self, result, context=None):
"""
Gets called after a ufunc.
"""
result = lib.item_from_zerodim(result)
if is_bool_dtype(result) or lib.is_scalar(result) or np.ndim(result) > 1:
return result
attrs = self._get_attributes_dict()
return Index(result, **attrs)
@cache_readonly
def dtype(self):
"""
Return the dtype object of the underlying data.
"""
return self._data.dtype
def ravel(self, order="C"):
"""
Return an ndarray of the flattened values of the underlying data.
Returns
-------
numpy.ndarray
Flattened array.
See Also
--------
numpy.ndarray.ravel
"""
return self._ndarray_values.ravel(order=order)
def view(self, cls=None):
# we need to see if we are subclassing an
# index type here
if cls is not None and not hasattr(cls, "_typ"):
result = self._data.view(cls)
else:
result = self._shallow_copy()
if isinstance(result, Index):
result._id = self._id
return result
def astype(self, dtype, copy=True):
"""
Create an Index with values cast to dtypes. The class of a new Index
is determined by dtype. When conversion is impossible, a ValueError
exception is raised.
Parameters
----------
dtype : numpy dtype or pandas type
Note that any signed integer `dtype` is treated as ``'int64'``,
and any unsigned integer `dtype` is treated as ``'uint64'``,
regardless of the size.
copy : bool, default True
By default, astype always returns a newly allocated object.
If copy is set to False and internal requirements on dtype are
satisfied, the original data is used to create a new Index
or the original Index is returned.
Returns
-------
Index
Index with values cast to specified dtype.
"""
if is_dtype_equal(self.dtype, dtype):
return self.copy() if copy else self
elif is_categorical_dtype(dtype):
from pandas.core.indexes.category import CategoricalIndex
return CategoricalIndex(self.values, name=self.name, dtype=dtype, copy=copy)
elif is_extension_array_dtype(dtype):
return Index(np.asarray(self), dtype=dtype, copy=copy)
try:
casted = self.values.astype(dtype, copy=copy)
except (TypeError, ValueError):
raise TypeError(f"Cannot cast {type(self).__name__} to dtype {dtype}")
return Index(casted, name=self.name, dtype=dtype)
_index_shared_docs[
"take"
] = """
Return a new %(klass)s of the values selected by the indices.
For internal compatibility with numpy arrays.
Parameters
----------
indices : list
Indices to be taken.
axis : int, optional
The axis over which to select values, always 0.
allow_fill : bool, default True
fill_value : bool, default None
If allow_fill=True and fill_value is not None, indices specified by
-1 is regarded as NA. If Index doesn't hold NA, raise ValueError.
Returns
-------
numpy.ndarray
Elements of given indices.
See Also
--------
numpy.ndarray.take
"""
@Appender(_index_shared_docs["take"] % _index_doc_kwargs)
def take(self, indices, axis=0, allow_fill=True, fill_value=None, **kwargs):
if kwargs:
nv.validate_take(tuple(), kwargs)
indices = ensure_platform_int(indices)
if self._can_hold_na:
taken = self._assert_take_fillable(
self.values,
indices,
allow_fill=allow_fill,
fill_value=fill_value,
na_value=self._na_value,
)
else:
if allow_fill and fill_value is not None:
cls_name = type(self).__name__
raise ValueError(
f"Unable to fill values because {cls_name} cannot contain NA"
)
taken = self.values.take(indices)
return self._shallow_copy(taken)
def _assert_take_fillable(
self, values, indices, allow_fill=True, fill_value=None, na_value=np.nan
):
"""
Internal method to handle NA filling of take.
"""
indices = ensure_platform_int(indices)
# only fill if we are passing a non-None fill_value
if allow_fill and fill_value is not None:
if (indices < -1).any():
raise ValueError(
"When allow_fill=True and fill_value is not None, "
"all indices must be >= -1"
)
taken = algos.take(
values, indices, allow_fill=allow_fill, fill_value=na_value
)
else:
taken = values.take(indices)
return taken
_index_shared_docs[
"repeat"
] = """
Repeat elements of a %(klass)s.
Returns a new %(klass)s where each element of the current %(klass)s
is repeated consecutively a given number of times.
Parameters
----------
repeats : int or array of ints
The number of repetitions for each element. This should be a
non-negative integer. Repeating 0 times will return an empty
%(klass)s.
axis : None
Must be ``None``. Has no effect but is accepted for compatibility
with numpy.
Returns
-------
repeated_index : %(klass)s
Newly created %(klass)s with repeated elements.
See Also
--------
Series.repeat : Equivalent function for Series.
numpy.repeat : Similar method for :class:`numpy.ndarray`.
Examples
--------
>>> idx = pd.Index(['a', 'b', 'c'])
>>> idx
Index(['a', 'b', 'c'], dtype='object')
>>> idx.repeat(2)
Index(['a', 'a', 'b', 'b', 'c', 'c'], dtype='object')
>>> idx.repeat([1, 2, 3])
Index(['a', 'b', 'b', 'c', 'c', 'c'], dtype='object')
"""
@Appender(_index_shared_docs["repeat"] % _index_doc_kwargs)
def repeat(self, repeats, axis=None):
repeats = ensure_platform_int(repeats)
nv.validate_repeat(tuple(), dict(axis=axis))
return self._shallow_copy(self._values.repeat(repeats))
# --------------------------------------------------------------------
# Copying Methods
def copy(self, name=None, deep=False, dtype=None, names=None):
"""
Make a copy of this object. Name and dtype sets those attributes on
the new object.
Parameters
----------
name : Label
deep : bool, default False
dtype : numpy dtype or pandas type, optional
names : list-like, optional
Kept for compatibility with MultiIndex. Should not be used.
Returns
-------
Index
Notes
-----
In most cases, there should be no functional difference from using
``deep``, but if ``deep`` is passed it will attempt to deepcopy.
"""
if deep:
new_index = self._shallow_copy(self._data.copy())
else:
new_index = self._shallow_copy()
names = self._validate_names(name=name, names=names, deep=deep)
new_index = new_index.set_names(names)
if dtype:
new_index = new_index.astype(dtype)
return new_index
def __copy__(self, **kwargs):
return self.copy(**kwargs)
def __deepcopy__(self, memo=None):
"""
Parameters
----------
memo, default None
Standard signature. Unused
"""
return self.copy(deep=True)
# --------------------------------------------------------------------
# Rendering Methods
def __repr__(self) -> str_t:
"""
Return a string representation for this object.
"""
klass_name = type(self).__name__
data = self._format_data()
attrs = self._format_attrs()
space = self._format_space()
attrs_str = [f"{k}={v}" for k, v in attrs]
prepr = f",{space}".join(attrs_str)
# no data provided, just attributes
if data is None:
data = ""
res = f"{klass_name}({data}{prepr})"
return res
def _format_space(self) -> str_t:
# using space here controls if the attributes
# are line separated or not (the default)
# max_seq_items = get_option('display.max_seq_items')
# if len(self) > max_seq_items:
# space = "\n%s" % (' ' * (len(klass) + 1))
return " "
@property
def _formatter_func(self):
"""
Return the formatter function.
"""
return default_pprint
def _format_data(self, name=None) -> str_t:
"""
Return the formatted data as a unicode string.
"""
# do we want to justify (only do so for non-objects)
is_justify = True
if self.inferred_type == "string":
is_justify = False
elif self.inferred_type == "categorical":
if is_object_dtype(self.categories): # type: ignore
is_justify = False
return format_object_summary(
self, self._formatter_func, is_justify=is_justify, name=name
)
def _format_attrs(self):
"""
Return a list of tuples of the (attr,formatted_value).
"""
return format_object_attrs(self)
def _mpl_repr(self):
# how to represent ourselves to matplotlib
return self.values
def format(self, name: bool = False, formatter=None, **kwargs):
"""
Render a string representation of the Index.
"""
header = []
if name:
header.append(
pprint_thing(self.name, escape_chars=("\t", "\r", "\n"))
if self.name is not None
else ""
)
if formatter is not None:
return header + list(self.map(formatter))
return self._format_with_header(header, **kwargs)
def _format_with_header(self, header, na_rep="NaN", **kwargs):
values = self.values
from pandas.io.formats.format import format_array
if is_categorical_dtype(values.dtype):
values = np.array(values)
elif is_object_dtype(values.dtype):
values = lib.maybe_convert_objects(values, safe=1)
if is_object_dtype(values.dtype):
result = [pprint_thing(x, escape_chars=("\t", "\r", "\n")) for x in values]
# could have nans
mask = isna(values)
if mask.any():
result = np.array(result)
result[mask] = na_rep
result = result.tolist()
else:
result = _trim_front(format_array(values, None, justify="left"))
return header + result
def to_native_types(self, slicer=None, **kwargs):
"""
Format specified values of `self` and return them.
Parameters
----------
slicer : int, array-like
An indexer into `self` that specifies which values
are used in the formatting process.
kwargs : dict
Options for specifying how the values should be formatted.
These options include the following:
1) na_rep : str
The value that serves as a placeholder for NULL values
2) quoting : bool or None
Whether or not there are quoted values in `self`
3) date_format : str
The format used to represent date-like values.
Returns
-------
numpy.ndarray
Formatted values.
"""
values = self
if slicer is not None:
values = values[slicer]
return values._format_native_types(**kwargs)
def _format_native_types(self, na_rep="", quoting=None, **kwargs):
"""
Actually format specific types of the index.
"""
mask = isna(self)
if not self.is_object() and not quoting:
values = np.asarray(self).astype(str)
else:
values = np.array(self, dtype=object, copy=True)
values[mask] = na_rep
return values
def _summary(self, name=None) -> str_t:
"""
Return a summarized representation.
Parameters
----------
name : str
name to use in the summary representation
Returns
-------
String with a summarized representation of the index
"""
if len(self) > 0:
head = self[0]
if hasattr(head, "format") and not isinstance(head, str):
head = head.format()
tail = self[-1]
if hasattr(tail, "format") and not isinstance(tail, str):
tail = tail.format()
index_summary = f", {head} to {tail}"
else:
index_summary = ""
if name is None:
name = type(self).__name__
return f"{name}: {len(self)} entries{index_summary}"
# --------------------------------------------------------------------
# Conversion Methods
def to_flat_index(self):
"""
Identity method.
.. versionadded:: 0.24.0
This is implemented for compatibility with subclass implementations
when chaining.
Returns
-------
pd.Index
Caller.
See Also
--------
MultiIndex.to_flat_index : Subclass implementation.
"""
return self
def to_series(self, index=None, name=None):
"""
Create a Series with both index and values equal to the index keys.
Useful with map for returning an indexer based on an index.
Parameters
----------
index : Index, optional
Index of resulting Series. If None, defaults to original index.
name : str, optional
Dame of resulting Series. If None, defaults to name of original
index.
Returns
-------
Series
The dtype will be based on the type of the Index values.
"""
from pandas import Series
if index is None:
index = self._shallow_copy()
if name is None:
name = self.name
return Series(self.values.copy(), index=index, name=name)
def to_frame(self, index: bool = True, name=None):
"""
Create a DataFrame with a column containing the Index.
.. versionadded:: 0.24.0
Parameters
----------
index : bool, default True
Set the index of the returned DataFrame as the original Index.
name : object, default None
The passed name should substitute for the index name (if it has
one).
Returns
-------
DataFrame
DataFrame containing the original Index data.
See Also
--------
Index.to_series : Convert an Index to a Series.
Series.to_frame : Convert Series to DataFrame.
Examples
--------
>>> idx = pd.Index(['Ant', 'Bear', 'Cow'], name='animal')
>>> idx.to_frame()
animal
animal
Ant Ant
Bear Bear
Cow Cow
By default, the original Index is reused. To enforce a new Index:
>>> idx.to_frame(index=False)
animal
0 Ant
1 Bear
2 Cow
To override the name of the resulting column, specify `name`:
>>> idx.to_frame(index=False, name='zoo')
zoo
0 Ant
1 Bear
2 Cow
"""
from pandas import DataFrame
if name is None:
name = self.name or 0
result = DataFrame({name: self._values.copy()})
if index:
result.index = self
return result
# --------------------------------------------------------------------
# Name-Centric Methods
@property
def name(self):
"""
Return Index or MultiIndex name.
"""
return self._name
@name.setter
def name(self, value):
if self._no_setting_name:
# Used in MultiIndex.levels to avoid silently ignoring name updates.
raise RuntimeError(
"Cannot set name on a level of a MultiIndex. Use "
"'MultiIndex.set_names' instead."
)
maybe_extract_name(value, None, type(self))
self._name = value
def _validate_names(self, name=None, names=None, deep: bool = False):
"""
Handles the quirks of having a singular 'name' parameter for general
Index and plural 'names' parameter for MultiIndex.
"""
from copy import deepcopy
if names is not None and name is not None:
raise TypeError("Can only provide one of `names` and `name`")
elif names is None and name is None:
return deepcopy(self.names) if deep else self.names
elif names is not None:
if not is_list_like(names):
raise TypeError("Must pass list-like as `names`.")
return names
else:
if not is_list_like(name):
return [name]
return name
def _get_names(self):
return FrozenList((self.name,))
def _set_names(self, values, level=None):
"""
Set new names on index. Each name has to be a hashable type.
Parameters
----------
values : str or sequence
name(s) to set
level : int, level name, or sequence of int/level names (default None)
If the index is a MultiIndex (hierarchical), level(s) to set (None
for all levels). Otherwise level must be None
Raises
------
TypeError if each name is not hashable.
"""
if not is_list_like(values):
raise ValueError("Names must be a list-like")
if len(values) != 1:
raise ValueError(f"Length of new names must be 1, got {len(values)}")
# GH 20527
# All items in 'name' need to be hashable:
for name in values:
if not is_hashable(name):
raise TypeError(f"{type(self).__name__}.name must be a hashable type")
self._name = values[0]
names = property(fset=_set_names, fget=_get_names)
def set_names(self, names, level=None, inplace: bool = False):
"""
Set Index or MultiIndex name.
Able to set new names partially and by level.
Parameters
----------
names : label or list of label
Name(s) to set.
level : int, label or list of int or label, optional
If the index is a MultiIndex, level(s) to set (None for all
levels). Otherwise level must be None.
inplace : bool, default False
Modifies the object directly, instead of creating a new Index or
MultiIndex.
Returns
-------
Index
The same type as the caller or None if inplace is True.
See Also
--------
Index.rename : Able to set new names without level.
Examples
--------
>>> idx = pd.Index([1, 2, 3, 4])
>>> idx
Int64Index([1, 2, 3, 4], dtype='int64')
>>> idx.set_names('quarter')
Int64Index([1, 2, 3, 4], dtype='int64', name='quarter')
>>> idx = pd.MultiIndex.from_product([['python', 'cobra'],
... [2018, 2019]])
>>> idx
MultiIndex([('python', 2018),
('python', 2019),
( 'cobra', 2018),
( 'cobra', 2019)],
)
>>> idx.set_names(['kind', 'year'], inplace=True)
>>> idx
MultiIndex([('python', 2018),
('python', 2019),
( 'cobra', 2018),
( 'cobra', 2019)],
names=['kind', 'year'])
>>> idx.set_names('species', level=0)
MultiIndex([('python', 2018),
('python', 2019),
( 'cobra', 2018),
( 'cobra', 2019)],
names=['species', 'year'])
"""
if level is not None and not isinstance(self, ABCMultiIndex):
raise ValueError("Level must be None for non-MultiIndex")
if level is not None and not is_list_like(level) and is_list_like(names):
raise TypeError("Names must be a string when a single level is provided.")
if not is_list_like(names) and level is None and self.nlevels > 1:
raise TypeError("Must pass list-like as `names`.")
if not is_list_like(names):
names = [names]
if level is not None and not is_list_like(level):
level = [level]
if inplace:
idx = self
else:
idx = self._shallow_copy()
idx._set_names(names, level=level)
if not inplace:
return idx
def rename(self, name, inplace=False):
"""
Alter Index or MultiIndex name.
Able to set new names without level. Defaults to returning new index.
Length of names must match number of levels in MultiIndex.
Parameters
----------
name : label or list of labels
Name(s) to set.
inplace : bool, default False
Modifies the object directly, instead of creating a new Index or
MultiIndex.
Returns
-------
Index
The same type as the caller or None if inplace is True.
See Also
--------
Index.set_names : Able to set new names partially and by level.
Examples
--------
>>> idx = pd.Index(['A', 'C', 'A', 'B'], name='score')
>>> idx.rename('grade')
Index(['A', 'C', 'A', 'B'], dtype='object', name='grade')
>>> idx = pd.MultiIndex.from_product([['python', 'cobra'],
... [2018, 2019]],
... names=['kind', 'year'])
>>> idx
MultiIndex([('python', 2018),
('python', 2019),
( 'cobra', 2018),
( 'cobra', 2019)],
names=['kind', 'year'])
>>> idx.rename(['species', 'year'])
MultiIndex([('python', 2018),
('python', 2019),
( 'cobra', 2018),
( 'cobra', 2019)],
names=['species', 'year'])
>>> idx.rename('species')
Traceback (most recent call last):
TypeError: Must pass list-like as `names`.
"""
return self.set_names([name], inplace=inplace)
# --------------------------------------------------------------------
# Level-Centric Methods
@property
def nlevels(self) -> int:
"""
Number of levels.
"""
return 1
def _sort_levels_monotonic(self):
"""
Compat with MultiIndex.
"""
return self
def _validate_index_level(self, level):
"""
Validate index level.
For single-level Index getting level number is a no-op, but some
verification must be done like in MultiIndex.
"""
if isinstance(level, int):
if level < 0 and level != -1:
raise IndexError(
"Too many levels: Index has only 1 level, "
f"{level} is not a valid level number"
)
elif level > 0:
raise IndexError(
f"Too many levels: Index has only 1 level, not {level + 1}"
)
elif level != self.name:
raise KeyError(
f"Requested level ({level}) does not match index name ({self.name})"
)
def _get_level_number(self, level) -> int:
self._validate_index_level(level)
return 0
def sortlevel(self, level=None, ascending=True, sort_remaining=None):
"""
For internal compatibility with with the Index API.
Sort the Index. This is for compat with MultiIndex
Parameters
----------
ascending : bool, default True
False to sort in descending order
level, sort_remaining are compat parameters
Returns
-------
Index
"""
return self.sort_values(return_indexer=True, ascending=ascending)
def _get_level_values(self, level):
"""
Return an Index of values for requested level.
This is primarily useful to get an individual level of values from a
MultiIndex, but is provided on Index as well for compatibility.
Parameters
----------
level : int or str
It is either the integer position or the name of the level.
Returns
-------
Index
Calling object, as there is only one level in the Index.
See Also
--------
MultiIndex.get_level_values : Get values for a level of a MultiIndex.
Notes
-----
For Index, level should be 0, since there are no multiple levels.
Examples
--------
>>> idx = pd.Index(list('abc'))
>>> idx
Index(['a', 'b', 'c'], dtype='object')
Get level values by supplying `level` as integer:
>>> idx.get_level_values(0)
Index(['a', 'b', 'c'], dtype='object')
"""
self._validate_index_level(level)
return self
get_level_values = _get_level_values
def droplevel(self, level=0):
"""
Return index with requested level(s) removed.
If resulting index has only 1 level left, the result will be
of Index type, not MultiIndex.
.. versionadded:: 0.23.1 (support for non-MultiIndex)
Parameters
----------
level : int, str, or list-like, default 0
If a string is given, must be the name of a level
If list-like, elements must be names or indexes of levels.
Returns
-------
Index or MultiIndex
"""
if not isinstance(level, (tuple, list)):
level = [level]
levnums = sorted(self._get_level_number(lev) for lev in level)[::-1]
if len(level) == 0:
return self
if len(level) >= self.nlevels:
raise ValueError(
f"Cannot remove {len(level)} levels from an index with {self.nlevels} "
"levels: at least one level must be left."
)
# The two checks above guarantee that here self is a MultiIndex
new_levels = list(self.levels)
new_codes = list(self.codes)
new_names = list(self.names)
for i in levnums:
new_levels.pop(i)
new_codes.pop(i)
new_names.pop(i)
if len(new_levels) == 1:
# set nan if needed
mask = new_codes[0] == -1
result = new_levels[0].take(new_codes[0])
if mask.any():
result = result.putmask(mask, np.nan)
result._name = new_names[0]
return result
else:
from pandas.core.indexes.multi import MultiIndex
return MultiIndex(
levels=new_levels,
codes=new_codes,
names=new_names,
verify_integrity=False,
)
def _get_grouper_for_level(self, mapper, level=None):
"""
Get index grouper corresponding to an index level
Parameters
----------
mapper: Group mapping function or None
Function mapping index values to groups
level : int or None
Index level
Returns
-------
grouper : Index
Index of values to group on.
labels : ndarray of int or None
Array of locations in level_index.
uniques : Index or None
Index of unique values for level.
"""
assert level is None or level == 0
if mapper is None:
grouper = self
else:
grouper = self.map(mapper)
return grouper, None, None
# --------------------------------------------------------------------
# Introspection Methods
@property
def is_monotonic(self) -> bool:
"""
Alias for is_monotonic_increasing.
"""
return self.is_monotonic_increasing
@property
def is_monotonic_increasing(self) -> bool:
"""
Return if the index is monotonic increasing (only equal or
increasing) values.
Examples
--------
>>> Index([1, 2, 3]).is_monotonic_increasing
True
>>> Index([1, 2, 2]).is_monotonic_increasing
True
>>> Index([1, 3, 2]).is_monotonic_increasing
False
"""
return self._engine.is_monotonic_increasing
@property
def is_monotonic_decreasing(self) -> bool:
"""
Return if the index is monotonic decreasing (only equal or
decreasing) values.
Examples
--------
>>> Index([3, 2, 1]).is_monotonic_decreasing
True
>>> Index([3, 2, 2]).is_monotonic_decreasing
True
>>> Index([3, 1, 2]).is_monotonic_decreasing
False
"""
return self._engine.is_monotonic_decreasing
@property
def _is_strictly_monotonic_increasing(self) -> bool:
"""
Return if the index is strictly monotonic increasing
(only increasing) values.
Examples
--------
>>> Index([1, 2, 3])._is_strictly_monotonic_increasing
True
>>> Index([1, 2, 2])._is_strictly_monotonic_increasing
False
>>> Index([1, 3, 2])._is_strictly_monotonic_increasing
False
"""
return self.is_unique and self.is_monotonic_increasing
@property
def _is_strictly_monotonic_decreasing(self) -> bool:
"""
Return if the index is strictly monotonic decreasing
(only decreasing) values.
Examples
--------
>>> Index([3, 2, 1])._is_strictly_monotonic_decreasing
True
>>> Index([3, 2, 2])._is_strictly_monotonic_decreasing
False
>>> Index([3, 1, 2])._is_strictly_monotonic_decreasing
False
"""
return self.is_unique and self.is_monotonic_decreasing
@cache_readonly
def is_unique(self) -> bool:
"""
Return if the index has unique values.
"""
return self._engine.is_unique
@property
def has_duplicates(self) -> bool:
"""
Check if the Index has duplicate values.
Returns
-------
bool
Whether or not the Index has duplicate values.
Examples
--------
>>> idx = pd.Index([1, 5, 7, 7])
>>> idx.has_duplicates
True
>>> idx = pd.Index([1, 5, 7])
>>> idx.has_duplicates
False
>>> idx = pd.Index(["Watermelon", "Orange", "Apple",
... "Watermelon"]).astype("category")
>>> idx.has_duplicates
True
>>> idx = pd.Index(["Orange", "Apple",
... "Watermelon"]).astype("category")
>>> idx.has_duplicates
False
"""
return not self.is_unique
def is_boolean(self) -> bool:
"""
Check if the Index only consists of booleans.
Returns
-------
bool
Whether or not the Index only consists of booleans.
See Also
--------
is_integer : Check if the Index only consists of integers.
is_floating : Check if the Index is a floating type.
is_numeric : Check if the Index only consists of numeric data.
is_object : Check if the Index is of the object dtype.
is_categorical : Check if the Index holds categorical data.
is_interval : Check if the Index holds Interval objects.
is_mixed : Check if the Index holds data with mixed data types.
Examples
--------
>>> idx = pd.Index([True, False, True])
>>> idx.is_boolean()
True
>>> idx = pd.Index(["True", "False", "True"])
>>> idx.is_boolean()
False
>>> idx = pd.Index([True, False, "True"])
>>> idx.is_boolean()
False
"""
return self.inferred_type in ["boolean"]
def is_integer(self) -> bool:
"""
Check if the Index only consists of integers.
Returns
-------
bool
Whether or not the Index only consists of integers.
See Also
--------
is_boolean : Check if the Index only consists of booleans.
is_floating : Check if the Index is a floating type.
is_numeric : Check if the Index only consists of numeric data.
is_object : Check if the Index is of the object dtype.
is_categorical : Check if the Index holds categorical data.
is_interval : Check if the Index holds Interval objects.
is_mixed : Check if the Index holds data with mixed data types.
Examples
--------
>>> idx = pd.Index([1, 2, 3, 4])
>>> idx.is_integer()
True
>>> idx = pd.Index([1.0, 2.0, 3.0, 4.0])
>>> idx.is_integer()
False
>>> idx = pd.Index(["Apple", "Mango", "Watermelon"])
>>> idx.is_integer()
False
"""
return self.inferred_type in ["integer"]
def is_floating(self) -> bool:
"""
Check if the Index is a floating type.
The Index may consist of only floats, NaNs, or a mix of floats,
integers, or NaNs.
Returns
-------
bool
Whether or not the Index only consists of only consists of floats, NaNs, or
a mix of floats, integers, or NaNs.
See Also
--------
is_boolean : Check if the Index only consists of booleans.
is_integer : Check if the Index only consists of integers.
is_numeric : Check if the Index only consists of numeric data.
is_object : Check if the Index is of the object dtype.
is_categorical : Check if the Index holds categorical data.
is_interval : Check if the Index holds Interval objects.
is_mixed : Check if the Index holds data with mixed data types.
Examples
--------
>>> idx = pd.Index([1.0, 2.0, 3.0, 4.0])
>>> idx.is_floating()
True
>>> idx = pd.Index([1.0, 2.0, np.nan, 4.0])
>>> idx.is_floating()
True
>>> idx = pd.Index([1, 2, 3, 4, np.nan])
>>> idx.is_floating()
True
>>> idx = pd.Index([1, 2, 3, 4])
>>> idx.is_floating()
False
"""
return self.inferred_type in ["floating", "mixed-integer-float", "integer-na"]
def is_numeric(self) -> bool:
"""
Check if the Index only consists of numeric data.
Returns
-------
bool
Whether or not the Index only consists of numeric data.
See Also
--------
is_boolean : Check if the Index only consists of booleans.
is_integer : Check if the Index only consists of integers.
is_floating : Check if the Index is a floating type.
is_object : Check if the Index is of the object dtype.
is_categorical : Check if the Index holds categorical data.
is_interval : Check if the Index holds Interval objects.
is_mixed : Check if the Index holds data with mixed data types.
Examples
--------
>>> idx = pd.Index([1.0, 2.0, 3.0, 4.0])
>>> idx.is_numeric()
True
>>> idx = pd.Index([1, 2, 3, 4.0])
>>> idx.is_numeric()
True
>>> idx = pd.Index([1, 2, 3, 4])
>>> idx.is_numeric()
True
>>> idx = pd.Index([1, 2, 3, 4.0, np.nan])
>>> idx.is_numeric()
True
>>> idx = pd.Index([1, 2, 3, 4.0, np.nan, "Apple"])
>>> idx.is_numeric()
False
"""
return self.inferred_type in ["integer", "floating"]
def is_object(self) -> bool:
"""
Check if the Index is of the object dtype.
Returns
-------
bool
Whether or not the Index is of the object dtype.
See Also
--------
is_boolean : Check if the Index only consists of booleans.
is_integer : Check if the Index only consists of integers.
is_floating : Check if the Index is a floating type.
is_numeric : Check if the Index only consists of numeric data.
is_categorical : Check if the Index holds categorical data.
is_interval : Check if the Index holds Interval objects.
is_mixed : Check if the Index holds data with mixed data types.
Examples
--------
>>> idx = pd.Index(["Apple", "Mango", "Watermelon"])
>>> idx.is_object()
True
>>> idx = pd.Index(["Apple", "Mango", 2.0])
>>> idx.is_object()
True
>>> idx = pd.Index(["Watermelon", "Orange", "Apple",
... "Watermelon"]).astype("category")
>>> idx.object()
False
>>> idx = pd.Index([1.0, 2.0, 3.0, 4.0])
>>> idx.is_object()
False
"""
return is_object_dtype(self.dtype)
def is_categorical(self) -> bool:
"""
Check if the Index holds categorical data.
Returns
-------
bool
True if the Index is categorical.
See Also
--------
CategoricalIndex : Index for categorical data.
is_boolean : Check if the Index only consists of booleans.
is_integer : Check if the Index only consists of integers.
is_floating : Check if the Index is a floating type.
is_numeric : Check if the Index only consists of numeric data.
is_object : Check if the Index is of the object dtype.
is_interval : Check if the Index holds Interval objects.
is_mixed : Check if the Index holds data with mixed data types.
Examples
--------
>>> idx = pd.Index(["Watermelon", "Orange", "Apple",
... "Watermelon"]).astype("category")
>>> idx.is_categorical()
True
>>> idx = pd.Index([1, 3, 5, 7])
>>> idx.is_categorical()
False
>>> s = pd.Series(["Peter", "Victor", "Elisabeth", "Mar"])
>>> s
0 Peter
1 Victor
2 Elisabeth
3 Mar
dtype: object
>>> s.index.is_categorical()
False
"""
return self.inferred_type in ["categorical"]
def is_interval(self) -> bool:
"""
Check if the Index holds Interval objects.
Returns
-------
bool
Whether or not the Index holds Interval objects.
See Also
--------
IntervalIndex : Index for Interval objects.
is_boolean : Check if the Index only consists of booleans.
is_integer : Check if the Index only consists of integers.
is_floating : Check if the Index is a floating type.
is_numeric : Check if the Index only consists of numeric data.
is_object : Check if the Index is of the object dtype.
is_categorical : Check if the Index holds categorical data.
is_mixed : Check if the Index holds data with mixed data types.
Examples
--------
>>> idx = pd.Index([pd.Interval(left=0, right=5),
... pd.Interval(left=5, right=10)])
>>> idx.is_interval()
True
>>> idx = pd.Index([1, 3, 5, 7])
>>> idx.is_interval()
False
"""
return self.inferred_type in ["interval"]
def is_mixed(self) -> bool:
"""
Check if the Index holds data with mixed data types.
Returns
-------
bool
Whether or not the Index holds data with mixed data types.
See Also
--------
is_boolean : Check if the Index only consists of booleans.
is_integer : Check if the Index only consists of integers.
is_floating : Check if the Index is a floating type.
is_numeric : Check if the Index only consists of numeric data.
is_object : Check if the Index is of the object dtype.
is_categorical : Check if the Index holds categorical data.
is_interval : Check if the Index holds Interval objects.
Examples
--------
>>> idx = pd.Index(['a', np.nan, 'b'])
>>> idx.is_mixed()
True
>>> idx = pd.Index([1.0, 2.0, 3.0, 5.0])
>>> idx.is_mixed()
False
"""
return self.inferred_type in ["mixed"]
def holds_integer(self) -> bool:
"""
Whether the type is an integer type.
"""
return self.inferred_type in ["integer", "mixed-integer"]
@cache_readonly
def inferred_type(self) -> str_t:
"""
Return a string of the type inferred from the values.
"""
return lib.infer_dtype(self, skipna=False)
@cache_readonly
def is_all_dates(self) -> bool:
"""
Whether or not the index values only consist of dates.
"""
return is_datetime_array(ensure_object(self.values))
# --------------------------------------------------------------------
# Pickle Methods
def __reduce__(self):
d = dict(data=self._data)
d.update(self._get_attributes_dict())
return _new_Index, (type(self), d), None
# --------------------------------------------------------------------
# Null Handling Methods
_na_value = np.nan
"""The expected NA value to use with this index."""
@cache_readonly
def _isnan(self):
"""
Return if each value is NaN.
"""
if self._can_hold_na:
return isna(self)
else:
# shouldn't reach to this condition by checking hasnans beforehand
values = np.empty(len(self), dtype=np.bool_)
values.fill(False)
return values
@cache_readonly
def _nan_idxs(self):
if self._can_hold_na:
return self._isnan.nonzero()[0]
else:
return np.array([], dtype=np.int64)
@cache_readonly
def hasnans(self) -> bool:
"""
Return if I have any nans; enables various perf speedups.
"""
if self._can_hold_na:
return bool(self._isnan.any())
else:
return False
def isna(self):
"""
Detect missing values.
Return a boolean same-sized object indicating if the values are NA.
NA values, such as ``None``, :attr:`numpy.NaN` or :attr:`pd.NaT`, get
mapped to ``True`` values.
Everything else get mapped to ``False`` values. Characters such as
empty strings `''` or :attr:`numpy.inf` are not considered NA values
(unless you set ``pandas.options.mode.use_inf_as_na = True``).
Returns
-------
numpy.ndarray
A boolean array of whether my values are NA.
See Also
--------
Index.notna : Boolean inverse of isna.
Index.dropna : Omit entries with missing values.
isna : Top-level isna.
Series.isna : Detect missing values in Series object.
Examples
--------
Show which entries in a pandas.Index are NA. The result is an
array.
>>> idx = pd.Index([5.2, 6.0, np.NaN])
>>> idx
Float64Index([5.2, 6.0, nan], dtype='float64')
>>> idx.isna()
array([False, False, True], dtype=bool)
Empty strings are not considered NA values. None is considered an NA
value.
>>> idx = pd.Index(['black', '', 'red', None])
>>> idx
Index(['black', '', 'red', None], dtype='object')
>>> idx.isna()
array([False, False, False, True], dtype=bool)
For datetimes, `NaT` (Not a Time) is considered as an NA value.
>>> idx = pd.DatetimeIndex([pd.Timestamp('1940-04-25'),
... pd.Timestamp(''), None, pd.NaT])
>>> idx
DatetimeIndex(['1940-04-25', 'NaT', 'NaT', 'NaT'],
dtype='datetime64[ns]', freq=None)
>>> idx.isna()
array([False, True, True, True], dtype=bool)
"""
return self._isnan
isnull = isna
def notna(self):
"""
Detect existing (non-missing) values.
Return a boolean same-sized object indicating if the values are not NA.
Non-missing values get mapped to ``True``. Characters such as empty
strings ``''`` or :attr:`numpy.inf` are not considered NA values
(unless you set ``pandas.options.mode.use_inf_as_na = True``).
NA values, such as None or :attr:`numpy.NaN`, get mapped to ``False``
values.
Returns
-------
numpy.ndarray
Boolean array to indicate which entries are not NA.
See Also
--------
Index.notnull : Alias of notna.
Index.isna: Inverse of notna.
notna : Top-level notna.
Examples
--------
Show which entries in an Index are not NA. The result is an
array.
>>> idx = pd.Index([5.2, 6.0, np.NaN])
>>> idx
Float64Index([5.2, 6.0, nan], dtype='float64')
>>> idx.notna()
array([ True, True, False])
Empty strings are not considered NA values. None is considered a NA
value.
>>> idx = pd.Index(['black', '', 'red', None])
>>> idx
Index(['black', '', 'red', None], dtype='object')
>>> idx.notna()
array([ True, True, True, False])
"""
return ~self.isna()
notnull = notna
def fillna(self, value=None, downcast=None):
"""
Fill NA/NaN values with the specified value.
Parameters
----------
value : scalar
Scalar value to use to fill holes (e.g. 0).
This value cannot be a list-likes.
downcast : dict, default is None
a dict of item->dtype of what to downcast if possible,
or the string 'infer' which will try to downcast to an appropriate
equal type (e.g. float64 to int64 if possible).
Returns
-------
filled : Index
"""
self._assert_can_do_op(value)
if self.hasnans:
result = self.putmask(self._isnan, value)
if downcast is None:
# no need to care metadata other than name
# because it can't have freq if
return Index(result, name=self.name)
return self._shallow_copy()
def dropna(self, how="any"):
"""
Return Index without NA/NaN values.
Parameters
----------
how : {'any', 'all'}, default 'any'
If the Index is a MultiIndex, drop the value when any or all levels
are NaN.
Returns
-------
valid : Index
"""
if how not in ("any", "all"):
raise ValueError(f"invalid how option: {how}")
if self.hasnans:
return self._shallow_copy(self._values[~self._isnan])
return self._shallow_copy()
# --------------------------------------------------------------------
# Uniqueness Methods
def unique(self, level=None):
"""
Return unique values in the index. Uniques are returned in order
of appearance, this does NOT sort.
Parameters
----------
level : int or str, optional, default None
Only return values from specified level (for MultiIndex).
.. versionadded:: 0.23.0
Returns
-------
Index without duplicates
See Also
--------
unique
Series.unique
"""
if level is not None:
self._validate_index_level(level)
result = super().unique()
return self._shallow_copy(result)
def drop_duplicates(self, keep="first"):
"""
Return Index with duplicate values removed.
Parameters
----------
keep : {'first', 'last', ``False``}, default 'first'
- 'first' : Drop duplicates except for the first occurrence.
- 'last' : Drop duplicates except for the last occurrence.
- ``False`` : Drop all duplicates.
Returns
-------
deduplicated : Index
See Also
--------
Series.drop_duplicates : Equivalent method on Series.
DataFrame.drop_duplicates : Equivalent method on DataFrame.
Index.duplicated : Related method on Index, indicating duplicate
Index values.
Examples
--------
Generate an pandas.Index with duplicate values.
>>> idx = pd.Index(['lama', 'cow', 'lama', 'beetle', 'lama', 'hippo'])
The `keep` parameter controls which duplicate values are removed.
The value 'first' keeps the first occurrence for each
set of duplicated entries. The default value of keep is 'first'.
>>> idx.drop_duplicates(keep='first')
Index(['lama', 'cow', 'beetle', 'hippo'], dtype='object')
The value 'last' keeps the last occurrence for each set of duplicated
entries.
>>> idx.drop_duplicates(keep='last')
Index(['cow', 'beetle', 'lama', 'hippo'], dtype='object')
The value ``False`` discards all sets of duplicated entries.
>>> idx.drop_duplicates(keep=False)
Index(['cow', 'beetle', 'hippo'], dtype='object')
"""
return super().drop_duplicates(keep=keep)
def duplicated(self, keep="first"):
"""
Indicate duplicate index values.
Duplicated values are indicated as ``True`` values in the resulting
array. Either all duplicates, all except the first, or all except the
last occurrence of duplicates can be indicated.
Parameters
----------
keep : {'first', 'last', False}, default 'first'
The value or values in a set of duplicates to mark as missing.
- 'first' : Mark duplicates as ``True`` except for the first
occurrence.
- 'last' : Mark duplicates as ``True`` except for the last
occurrence.
- ``False`` : Mark all duplicates as ``True``.
Returns
-------
numpy.ndarray
See Also
--------
Series.duplicated : Equivalent method on pandas.Series.
DataFrame.duplicated : Equivalent method on pandas.DataFrame.
Index.drop_duplicates : Remove duplicate values from Index.
Examples
--------
By default, for each set of duplicated values, the first occurrence is
set to False and all others to True:
>>> idx = pd.Index(['lama', 'cow', 'lama', 'beetle', 'lama'])
>>> idx.duplicated()
array([False, False, True, False, True])
which is equivalent to
>>> idx.duplicated(keep='first')
array([False, False, True, False, True])
By using 'last', the last occurrence of each set of duplicated values
is set on False and all others on True:
>>> idx.duplicated(keep='last')
array([ True, False, True, False, False])
By setting keep on ``False``, all duplicates are True:
>>> idx.duplicated(keep=False)
array([ True, False, True, False, True])
"""
return super().duplicated(keep=keep)
def _get_unique_index(self, dropna: bool = False):
"""
Returns an index containing unique values.
Parameters
----------
dropna : bool, default False
If True, NaN values are dropped.
Returns
-------
uniques : index
"""
if self.is_unique and not dropna:
return self
values = self.values
if not self.is_unique:
values = self.unique()
if not isinstance(self, ABCMultiIndex):
# extract an array to pass to _shallow_copy
values = values._data
if dropna:
try:
if self.hasnans:
values = values[~isna(values)]
except NotImplementedError:
pass
return self._shallow_copy(values)
# --------------------------------------------------------------------
# Arithmetic & Logical Methods
def __add__(self, other):
if isinstance(other, (ABCSeries, ABCDataFrame)):
return NotImplemented
from pandas import Series
return Index(Series(self) + other)
def __radd__(self, other):
from pandas import Series
return Index(other + Series(self))
def __iadd__(self, other):
# alias for __add__
return self + other
def __sub__(self, other):
return Index(np.array(self) - other)
def __rsub__(self, other):
# wrap Series to ensure we pin name correctly
from pandas import Series
return Index(other - Series(self))
def __and__(self, other):
return self.intersection(other)
def __or__(self, other):
return self.union(other)
def __xor__(self, other):
return self.symmetric_difference(other)
def __nonzero__(self):
raise ValueError(
f"The truth value of a {type(self).__name__} is ambiguous. "
"Use a.empty, a.bool(), a.item(), a.any() or a.all()."
)
__bool__ = __nonzero__
# --------------------------------------------------------------------
# Set Operation Methods
def _get_reconciled_name_object(self, other):
"""
If the result of a set operation will be self,
return self, unless the name changes, in which
case make a shallow copy of self.
"""
name = get_op_result_name(self, other)
if self.name != name:
return self._shallow_copy(name=name)
return self
def _union_incompatible_dtypes(self, other, sort):
"""
Casts this and other index to object dtype to allow the formation
of a union between incompatible types.
Parameters
----------
other : Index or array-like
sort : False or None, default False
Whether to sort the resulting index.
* False : do not sort the result.
* None : sort the result, except when `self` and `other` are equal
or when the values cannot be compared.
Returns
-------
Index
"""
this = self.astype(object, copy=False)
# cast to Index for when `other` is list-like
other = Index(other).astype(object, copy=False)
return Index.union(this, other, sort=sort).astype(object, copy=False)
def _is_compatible_with_other(self, other) -> bool:
"""
Check whether this and the other dtype are compatible with each other.
Meaning a union can be formed between them without needing to be cast
to dtype object.
Parameters
----------
other : Index or array-like
Returns
-------
bool
"""
return type(self) is type(other) and is_dtype_equal(self.dtype, other.dtype)
def _validate_sort_keyword(self, sort):
if sort not in [None, False]:
raise ValueError(
"The 'sort' keyword only takes the values of "
f"None or False; {sort} was passed."
)
def union(self, other, sort=None):
"""
Form the union of two Index objects.
If the Index objects are incompatible, both Index objects will be
cast to dtype('object') first.
.. versionchanged:: 0.25.0
Parameters
----------
other : Index or array-like
sort : bool or None, default None
Whether to sort the resulting Index.
* None : Sort the result, except when
1. `self` and `other` are equal.
2. `self` or `other` has length 0.
3. Some values in `self` or `other` cannot be compared.
A RuntimeWarning is issued in this case.
* False : do not sort the result.
.. versionadded:: 0.24.0
.. versionchanged:: 0.24.1
Changed the default value from ``True`` to ``None``
(without change in behaviour).
Returns
-------
union : Index
Examples
--------
Union matching dtypes
>>> idx1 = pd.Index([1, 2, 3, 4])
>>> idx2 = pd.Index([3, 4, 5, 6])
>>> idx1.union(idx2)
Int64Index([1, 2, 3, 4, 5, 6], dtype='int64')
Union mismatched dtypes
>>> idx1 = pd.Index(['a', 'b', 'c', 'd'])
>>> idx2 = pd.Index([1, 2, 3, 4])
>>> idx1.union(idx2)
Index(['a', 'b', 'c', 'd', 1, 2, 3, 4], dtype='object')
"""
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
if not self._is_compatible_with_other(other):
return self._union_incompatible_dtypes(other, sort=sort)
return self._union(other, sort=sort)
def _union(self, other, sort):
"""
Specific union logic should go here. In subclasses, union behavior
should be overwritten here rather than in `self.union`.
Parameters
----------
other : Index or array-like
sort : False or None, default False
Whether to sort the resulting index.
* False : do not sort the result.
* None : sort the result, except when `self` and `other` are equal
or when the values cannot be compared.
Returns
-------
Index
"""
if not len(other) or self.equals(other):
return self._get_reconciled_name_object(other)
if not len(self):
return other._get_reconciled_name_object(self)
# TODO(EA): setops-refactor, clean all this up
if is_datetime64tz_dtype(self):
lvals = self._ndarray_values
else:
lvals = self._values
if is_datetime64tz_dtype(other):
rvals = other._ndarray_values
else:
rvals = other._values
if sort is None and self.is_monotonic and other.is_monotonic:
try:
result = self._outer_indexer(lvals, rvals)[0]
except TypeError:
# incomparable objects
result = list(lvals)
# worth making this faster? a very unusual case
value_set = set(lvals)
result.extend([x for x in rvals if x not in value_set])
result = Index(result)._values # do type inference here
else:
# find indexes of things in "other" that are not in "self"
if self.is_unique:
indexer = self.get_indexer(other)
indexer = (indexer == -1).nonzero()[0]
else:
indexer = algos.unique1d(self.get_indexer_non_unique(other)[1])
if len(indexer) > 0:
other_diff = algos.take_nd(rvals, indexer, allow_fill=False)
result = concat_compat((lvals, other_diff))
else:
result = lvals
if sort is None:
try:
result = algos.safe_sort(result)
except TypeError as err:
warnings.warn(
f"{err}, sort order is undefined for incomparable objects",
RuntimeWarning,
stacklevel=3,
)
# for subclasses
return self._wrap_setop_result(other, result)
def _wrap_setop_result(self, other, result):
name = get_op_result_name(self, other)
return self._shallow_copy(result, name=name)
# TODO: standardize return type of non-union setops type(self vs other)
def intersection(self, other, sort=False):
"""
Form the intersection of two Index objects.
This returns a new Index with elements common to the index and `other`.
Parameters
----------
other : Index or array-like
sort : False or None, default False
Whether to sort the resulting index.
* False : do not sort the result.
* None : sort the result, except when `self` and `other` are equal
or when the values cannot be compared.
.. versionadded:: 0.24.0
.. versionchanged:: 0.24.1
Changed the default from ``True`` to ``False``, to match
the behaviour of 0.23.4 and earlier.
Returns
-------
intersection : Index
Examples
--------
>>> idx1 = pd.Index([1, 2, 3, 4])
>>> idx2 = pd.Index([3, 4, 5, 6])
>>> idx1.intersection(idx2)
Int64Index([3, 4], dtype='int64')
"""
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
other = ensure_index(other)
if self.equals(other):
return self._get_reconciled_name_object(other)
if not is_dtype_equal(self.dtype, other.dtype):
this = self.astype("O")
other = other.astype("O")
return this.intersection(other, sort=sort)
# TODO(EA): setops-refactor, clean all this up
lvals = self._values
rvals = other._values
if self.is_monotonic and other.is_monotonic:
try:
result = self._inner_indexer(lvals, rvals)[0]
except TypeError:
pass
else:
return self._wrap_setop_result(other, result)
try:
indexer = Index(rvals).get_indexer(lvals)
indexer = indexer.take((indexer != -1).nonzero()[0])
except (InvalidIndexError, IncompatibleFrequency):
# InvalidIndexError raised by get_indexer if non-unique
# IncompatibleFrequency raised by PeriodIndex.get_indexer
indexer = algos.unique1d(Index(rvals).get_indexer_non_unique(lvals)[0])
indexer = indexer[indexer != -1]
taken = other.take(indexer)
res_name = get_op_result_name(self, other)
if sort is None:
taken = algos.safe_sort(taken.values)
return self._shallow_copy(taken, name=res_name)
taken.name = res_name
return taken
def difference(self, other, sort=None):
"""
Return a new Index with elements from the index that are not in
`other`.
This is the set difference of two Index objects.
Parameters
----------
other : Index or array-like
sort : False or None, default None
Whether to sort the resulting index. By default, the
values are attempted to be sorted, but any TypeError from
incomparable elements is caught by pandas.
* None : Attempt to sort the result, but catch any TypeErrors
from comparing incomparable elements.
* False : Do not sort the result.
.. versionadded:: 0.24.0
.. versionchanged:: 0.24.1
Changed the default value from ``True`` to ``None``
(without change in behaviour).
Returns
-------
difference : Index
Examples
--------
>>> idx1 = pd.Index([2, 1, 3, 4])
>>> idx2 = pd.Index([3, 4, 5, 6])
>>> idx1.difference(idx2)
Int64Index([1, 2], dtype='int64')
>>> idx1.difference(idx2, sort=False)
Int64Index([2, 1], dtype='int64')
"""
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
if self.equals(other):
# pass an empty np.ndarray with the appropriate dtype
return self._shallow_copy(self._data[:0])
other, result_name = self._convert_can_do_setop(other)
this = self._get_unique_index()
indexer = this.get_indexer(other)
indexer = indexer.take((indexer != -1).nonzero()[0])
label_diff = np.setdiff1d(np.arange(this.size), indexer, assume_unique=True)
the_diff = this.values.take(label_diff)
if sort is None:
try:
the_diff = algos.safe_sort(the_diff)
except TypeError:
pass
return this._shallow_copy(the_diff, name=result_name)
def symmetric_difference(self, other, result_name=None, sort=None):
"""
Compute the symmetric difference of two Index objects.
Parameters
----------
other : Index or array-like
result_name : str
sort : False or None, default None
Whether to sort the resulting index. By default, the
values are attempted to be sorted, but any TypeError from
incomparable elements is caught by pandas.
* None : Attempt to sort the result, but catch any TypeErrors
from comparing incomparable elements.
* False : Do not sort the result.
.. versionadded:: 0.24.0
.. versionchanged:: 0.24.1
Changed the default value from ``True`` to ``None``
(without change in behaviour).
Returns
-------
symmetric_difference : Index
Notes
-----
``symmetric_difference`` contains elements that appear in either
``idx1`` or ``idx2`` but not both. Equivalent to the Index created by
``idx1.difference(idx2) | idx2.difference(idx1)`` with duplicates
dropped.
Examples
--------
>>> idx1 = pd.Index([1, 2, 3, 4])
>>> idx2 = pd.Index([2, 3, 4, 5])
>>> idx1.symmetric_difference(idx2)
Int64Index([1, 5], dtype='int64')
You can also use the ``^`` operator:
>>> idx1 ^ idx2
Int64Index([1, 5], dtype='int64')
"""
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
other, result_name_update = self._convert_can_do_setop(other)
if result_name is None:
result_name = result_name_update
this = self._get_unique_index()
other = other._get_unique_index()
indexer = this.get_indexer(other)
# {this} minus {other}
common_indexer = indexer.take((indexer != -1).nonzero()[0])
left_indexer = np.setdiff1d(
np.arange(this.size), common_indexer, assume_unique=True
)
left_diff = this._values.take(left_indexer)
# {other} minus {this}
right_indexer = (indexer == -1).nonzero()[0]
right_diff = other._values.take(right_indexer)
the_diff = concat_compat([left_diff, right_diff])
if sort is None:
try:
the_diff = algos.safe_sort(the_diff)
except TypeError:
pass
attribs = self._get_attributes_dict()
attribs["name"] = result_name
if "freq" in attribs:
attribs["freq"] = None
return self._shallow_copy_with_infer(the_diff, **attribs)
def _assert_can_do_setop(self, other):
if not is_list_like(other):
raise TypeError("Input must be Index or array-like")
return True
def _convert_can_do_setop(self, other):
if not isinstance(other, Index):
other = Index(other, name=self.name)
result_name = self.name
else:
result_name = get_op_result_name(self, other)
return other, result_name
# --------------------------------------------------------------------
# Indexing Methods
def get_loc(self, key, method=None, tolerance=None):
"""
Get integer location, slice or boolean mask for requested label.
Parameters
----------
key : label
method : {None, 'pad'/'ffill', 'backfill'/'bfill', 'nearest'}, optional
* default: exact matches only.
* pad / ffill: find the PREVIOUS index value if no exact match.
* backfill / bfill: use NEXT index value if no exact match
* nearest: use the NEAREST index value if no exact match. Tied
distances are broken by preferring the larger index value.
tolerance : int or float, optional
Maximum distance from index value for inexact matches. The value of
the index at the matching location most satisfy the equation
``abs(index[loc] - key) <= tolerance``.
.. versionadded:: 0.21.0 (list-like tolerance)
Returns
-------
loc : int if unique index, slice if monotonic index, else mask
Examples
--------
>>> unique_index = pd.Index(list('abc'))
>>> unique_index.get_loc('b')
1
>>> monotonic_index = pd.Index(list('abbc'))
>>> monotonic_index.get_loc('b')
slice(1, 3, None)
>>> non_monotonic_index = pd.Index(list('abcb'))
>>> non_monotonic_index.get_loc('b')
array([False, True, False, True], dtype=bool)
"""
if method is None:
if tolerance is not None:
raise ValueError(
"tolerance argument only valid if using pad, "
"backfill or nearest lookups"
)
casted_key = self._maybe_cast_indexer(key)
try:
return self._engine.get_loc(casted_key)
except KeyError:
raise KeyError(key)
if tolerance is not None:
tolerance = self._convert_tolerance(tolerance, np.asarray(key))
indexer = self.get_indexer([key], method=method, tolerance=tolerance)
if indexer.ndim > 1 or indexer.size > 1:
raise TypeError("get_loc requires scalar valued input")
loc = indexer.item()
if loc == -1:
raise KeyError(key)
return loc
_index_shared_docs[
"get_indexer"
] = """
Compute indexer and mask for new index given the current index. The
indexer should be then used as an input to ndarray.take to align the
current data to the new index.
Parameters
----------
target : %(target_klass)s
method : {None, 'pad'/'ffill', 'backfill'/'bfill', 'nearest'}, optional
* default: exact matches only.
* pad / ffill: find the PREVIOUS index value if no exact match.
* backfill / bfill: use NEXT index value if no exact match
* nearest: use the NEAREST index value if no exact match. Tied
distances are broken by preferring the larger index value.
limit : int, optional
Maximum number of consecutive labels in ``target`` to match for
inexact matches.
tolerance : optional
Maximum distance between original and new labels for inexact
matches. The values of the index at the matching locations most
satisfy the equation ``abs(index[indexer] - target) <= tolerance``.
Tolerance may be a scalar value, which applies the same tolerance
to all values, or list-like, which applies variable tolerance per
element. List-like includes list, tuple, array, Series, and must be
the same size as the index and its dtype must exactly match the
index's type.
.. versionadded:: 0.21.0 (list-like tolerance)
Returns
-------
indexer : ndarray of int
Integers from 0 to n - 1 indicating that the index at these
positions matches the corresponding target values. Missing values
in the target are marked by -1.
%(raises_section)s
Examples
--------
>>> index = pd.Index(['c', 'a', 'b'])
>>> index.get_indexer(['a', 'b', 'x'])
array([ 1, 2, -1])
Notice that the return value is an array of locations in ``index``
and ``x`` is marked by -1, as it is not in ``index``.
"""
@Appender(_index_shared_docs["get_indexer"] % _index_doc_kwargs)
def get_indexer(
self, target, method=None, limit=None, tolerance=None
) -> np.ndarray:
method = missing.clean_reindex_fill_method(method)
target = ensure_index(target)
if tolerance is not None:
tolerance = self._convert_tolerance(tolerance, target)
# Treat boolean labels passed to a numeric index as not found. Without
# this fix False and True would be treated as 0 and 1 respectively.
# (GH #16877)
if target.is_boolean() and self.is_numeric():
return ensure_platform_int(np.repeat(-1, target.size))
pself, ptarget = self._maybe_promote(target)
if pself is not self or ptarget is not target:
return pself.get_indexer(
ptarget, method=method, limit=limit, tolerance=tolerance
)
if not is_dtype_equal(self.dtype, target.dtype):
this = self.astype(object)
target = target.astype(object)
return this.get_indexer(
target, method=method, limit=limit, tolerance=tolerance
)
if not self.is_unique:
raise InvalidIndexError(
"Reindexing only valid with uniquely valued Index objects"
)
if method == "pad" or method == "backfill":
indexer = self._get_fill_indexer(target, method, limit, tolerance)
elif method == "nearest":
indexer = self._get_nearest_indexer(target, limit, tolerance)
else:
if tolerance is not None:
raise ValueError(
"tolerance argument only valid if doing pad, "
"backfill or nearest reindexing"
)
if limit is not None:
raise ValueError(
"limit argument only valid if doing pad, "
"backfill or nearest reindexing"
)
indexer = self._engine.get_indexer(target._ndarray_values)
return ensure_platform_int(indexer)
def _convert_tolerance(self, tolerance, target):
# override this method on subclasses
tolerance = np.asarray(tolerance)
if target.size != tolerance.size and tolerance.size > 1:
raise ValueError("list-like tolerance size must match target index size")
return tolerance
def _get_fill_indexer(
self, target: "Index", method: str_t, limit=None, tolerance=None
) -> np.ndarray:
if self.is_monotonic_increasing and target.is_monotonic_increasing:
engine_method = (
self._engine.get_pad_indexer
if method == "pad"
else self._engine.get_backfill_indexer
)
indexer = engine_method(target._ndarray_values, limit)
else:
indexer = self._get_fill_indexer_searchsorted(target, method, limit)
if tolerance is not None:
indexer = self._filter_indexer_tolerance(
target._ndarray_values, indexer, tolerance
)
return indexer
def _get_fill_indexer_searchsorted(
self, target: "Index", method: str_t, limit=None
) -> np.ndarray:
"""
Fallback pad/backfill get_indexer that works for monotonic decreasing
indexes and non-monotonic targets.
"""
if limit is not None:
raise ValueError(
f"limit argument for {repr(method)} method only well-defined "
"if index and target are monotonic"
)
side = "left" if method == "pad" else "right"
# find exact matches first (this simplifies the algorithm)
indexer = self.get_indexer(target)
nonexact = indexer == -1
indexer[nonexact] = self._searchsorted_monotonic(target[nonexact], side)
if side == "left":
# searchsorted returns "indices into a sorted array such that,
# if the corresponding elements in v were inserted before the
# indices, the order of a would be preserved".
# Thus, we need to subtract 1 to find values to the left.
indexer[nonexact] -= 1
# This also mapped not found values (values of 0 from
# np.searchsorted) to -1, which conveniently is also our
# sentinel for missing values
else:
# Mark indices to the right of the largest value as not found
indexer[indexer == len(self)] = -1
return indexer
def _get_nearest_indexer(self, target: "Index", limit, tolerance) -> np.ndarray:
"""
Get the indexer for the nearest index labels; requires an index with
values that can be subtracted from each other (e.g., not strings or
tuples).
"""
left_indexer = self.get_indexer(target, "pad", limit=limit)
right_indexer = self.get_indexer(target, "backfill", limit=limit)
left_distances = np.abs(self[left_indexer] - target)
right_distances = np.abs(self[right_indexer] - target)
op = operator.lt if self.is_monotonic_increasing else operator.le
indexer = np.where(
op(left_distances, right_distances) | (right_indexer == -1),
left_indexer,
right_indexer,
)
if tolerance is not None:
indexer = self._filter_indexer_tolerance(target, indexer, tolerance)
return indexer
def _filter_indexer_tolerance(
self, target: "Index", indexer: np.ndarray, tolerance
) -> np.ndarray:
distance = abs(self.values[indexer] - target)
indexer = np.where(distance <= tolerance, indexer, -1)
return indexer
# --------------------------------------------------------------------
# Indexer Conversion Methods
def _get_partial_string_timestamp_match_key(self, key):
"""
Translate any partial string timestamp matches in key, returning the
new key.
Only relevant for MultiIndex.
"""
# GH#10331
return key
def _convert_scalar_indexer(self, key, kind: str_t):
"""
Convert a scalar indexer.
Parameters
----------
key : label of the slice bound
kind : {'loc', 'getitem'}
"""
assert kind in ["loc", "getitem"]
if len(self) and not isinstance(self, ABCMultiIndex):
# we can raise here if we are definitive that this
# is positional indexing (eg. .loc on with a float)
# or label indexing if we are using a type able
# to be represented in the index
if kind == "getitem" and is_float(key):
if not self.is_floating():
self._invalid_indexer("label", key)
elif kind == "loc" and is_float(key):
# we want to raise KeyError on string/mixed here
# technically we *could* raise a TypeError
# on anything but mixed though
if self.inferred_type not in [
"floating",
"mixed-integer-float",
"integer-na",
"string",
"mixed",
]:
self._invalid_indexer("label", key)
elif kind == "loc" and is_integer(key):
if not self.holds_integer():
self._invalid_indexer("label", key)
return key
def _validate_positional_slice(self, key: slice):
"""
For positional indexing, a slice must have either int or None
for each of start, stop, and step.
"""
self._validate_indexer("positional", key.start, "iloc")
self._validate_indexer("positional", key.stop, "iloc")
self._validate_indexer("positional", key.step, "iloc")
def _convert_slice_indexer(self, key: slice, kind: str_t):
"""
Convert a slice indexer.
By definition, these are labels unless 'iloc' is passed in.
Floats are not allowed as the start, step, or stop of the slice.
Parameters
----------
key : label of the slice bound
kind : {'loc', 'getitem'}
"""
assert kind in ["loc", "getitem"], kind
# potentially cast the bounds to integers
start, stop, step = key.start, key.stop, key.step
# figure out if this is a positional indexer
def is_int(v):
return v is None or is_integer(v)
is_null_slicer = start is None and stop is None
is_index_slice = is_int(start) and is_int(stop)
is_positional = is_index_slice and not (
self.is_integer() or self.is_categorical()
)
if kind == "getitem":
"""
called from the getitem slicers, validate that we are in fact
integers
"""
if self.is_integer() or is_index_slice:
self._validate_indexer("slice", key.start, "getitem")
self._validate_indexer("slice", key.stop, "getitem")
self._validate_indexer("slice", key.step, "getitem")
return key
# convert the slice to an indexer here
# if we are mixed and have integers
if is_positional and self.is_mixed():
try:
# Validate start & stop
if start is not None:
self.get_loc(start)
if stop is not None:
self.get_loc(stop)
is_positional = False
except KeyError:
pass
if is_null_slicer:
indexer = key
elif is_positional:
indexer = key
else:
indexer = self.slice_indexer(start, stop, step, kind=kind)
return indexer
def _convert_listlike_indexer(self, keyarr):
"""
Parameters
----------
keyarr : list-like
Indexer to convert.
Returns
-------
indexer : numpy.ndarray or None
Return an ndarray or None if cannot convert.
keyarr : numpy.ndarray
Return tuple-safe keys.
"""
if isinstance(keyarr, Index):
keyarr = self._convert_index_indexer(keyarr)
else:
keyarr = self._convert_arr_indexer(keyarr)
indexer = self._convert_list_indexer(keyarr)
return indexer, keyarr
def _convert_arr_indexer(self, keyarr):
"""
Convert an array-like indexer to the appropriate dtype.
Parameters
----------
keyarr : array-like
Indexer to convert.
Returns
-------
converted_keyarr : array-like
"""
keyarr = com.asarray_tuplesafe(keyarr)
return keyarr
def _convert_index_indexer(self, keyarr):
"""
Convert an Index indexer to the appropriate dtype.
Parameters
----------
keyarr : Index (or sub-class)
Indexer to convert.
Returns
-------
converted_keyarr : Index (or sub-class)
"""
return keyarr
def _convert_list_indexer(self, keyarr):
"""
Convert a list-like indexer to the appropriate dtype.
Parameters
----------
keyarr : Index (or sub-class)
Indexer to convert.
kind : iloc, loc, optional
Returns
-------
positional indexer or None
"""
return None
def _invalid_indexer(self, form: str_t, key):
"""
Consistent invalid indexer message.
"""
raise TypeError(
f"cannot do {form} indexing on {type(self).__name__} with these "
f"indexers [{key}] of type {type(key).__name__}"
)
# --------------------------------------------------------------------
# Reindex Methods
def _can_reindex(self, indexer):
"""
Check if we are allowing reindexing with this particular indexer.
Parameters
----------
indexer : an integer indexer
Raises
------
ValueError if its a duplicate axis
"""
# trying to reindex on an axis with duplicates
if not self.is_unique and len(indexer):
raise ValueError("cannot reindex from a duplicate axis")
def reindex(self, target, method=None, level=None, limit=None, tolerance=None):
"""
Create index with target's values (move/add/delete values
as necessary).
Parameters
----------
target : an iterable
Returns
-------
new_index : pd.Index
Resulting index.
indexer : np.ndarray or None
Indices of output values in original index.
"""
# GH6552: preserve names when reindexing to non-named target
# (i.e. neither Index nor Series).
preserve_names = not hasattr(target, "name")
# GH7774: preserve dtype/tz if target is empty and not an Index.
target = _ensure_has_len(target) # target may be an iterator
if not isinstance(target, Index) and len(target) == 0:
attrs = self._get_attributes_dict()
attrs.pop("freq", None) # don't preserve freq
if isinstance(self, ABCRangeIndex):
values = range(0)
else:
values = self._data[:0] # appropriately-dtyped empty array
target = self._simple_new(values, dtype=self.dtype, **attrs)
else:
target = ensure_index(target)
if level is not None:
if method is not None:
raise TypeError("Fill method not supported if level passed")
_, indexer, _ = self._join_level(
target, level, how="right", return_indexers=True
)
else:
if self.equals(target):
indexer = None
else:
# check is_overlapping for IntervalIndex compat
if self.is_unique and not getattr(self, "is_overlapping", False):
indexer = self.get_indexer(
target, method=method, limit=limit, tolerance=tolerance
)
else:
if method is not None or limit is not None:
raise ValueError(
"cannot reindex a non-unique index "
"with a method or limit"
)
indexer, missing = self.get_indexer_non_unique(target)
if preserve_names and target.nlevels == 1 and target.name != self.name:
target = target.copy()
target.name = self.name
return target, indexer
def _reindex_non_unique(self, target):
"""
Create a new index with target's values (move/add/delete values as
necessary) use with non-unique Index and a possibly non-unique target.
Parameters
----------
target : an iterable
Returns
-------
new_index : pd.Index
Resulting index.
indexer : np.ndarray or None
Indices of output values in original index.
"""
target = ensure_index(target)
indexer, missing = self.get_indexer_non_unique(target)
check = indexer != -1
new_labels = self.take(indexer[check])
new_indexer = None
if len(missing):
length = np.arange(len(indexer))
missing = ensure_platform_int(missing)
missing_labels = target.take(missing)
missing_indexer = ensure_int64(length[~check])
cur_labels = self.take(indexer[check]).values
cur_indexer = ensure_int64(length[check])
new_labels = np.empty(tuple([len(indexer)]), dtype=object)
new_labels[cur_indexer] = cur_labels
new_labels[missing_indexer] = missing_labels
# a unique indexer
if target.is_unique:
# see GH5553, make sure we use the right indexer
new_indexer = np.arange(len(indexer))
new_indexer[cur_indexer] = np.arange(len(cur_labels))
new_indexer[missing_indexer] = -1
# we have a non_unique selector, need to use the original
# indexer here
else:
# need to retake to have the same size as the indexer
indexer[~check] = -1
# reset the new indexer to account for the new size
new_indexer = np.arange(len(self.take(indexer)))
new_indexer[~check] = -1
new_index = self._shallow_copy_with_infer(new_labels)
return new_index, indexer, new_indexer
# --------------------------------------------------------------------
# Join Methods
def join(self, other, how="left", level=None, return_indexers=False, sort=False):
"""
Compute join_index and indexers to conform data
structures to the new index.
Parameters
----------
other : Index
how : {'left', 'right', 'inner', 'outer'}
level : int or level name, default None
return_indexers : bool, default False
sort : bool, default False
Sort the join keys lexicographically in the result Index. If False,
the order of the join keys depends on the join type (how keyword).
Returns
-------
join_index, (left_indexer, right_indexer)
"""
self_is_mi = isinstance(self, ABCMultiIndex)
other_is_mi = isinstance(other, ABCMultiIndex)
# try to figure out the join level
# GH3662
if level is None and (self_is_mi or other_is_mi):
# have the same levels/names so a simple join
if self.names == other.names:
pass
else:
return self._join_multi(other, how=how, return_indexers=return_indexers)
# join on the level
if level is not None and (self_is_mi or other_is_mi):
return self._join_level(
other, level, how=how, return_indexers=return_indexers
)
other = ensure_index(other)
if len(other) == 0 and how in ("left", "outer"):
join_index = self._shallow_copy()
if return_indexers:
rindexer = np.repeat(-1, len(join_index))
return join_index, None, rindexer
else:
return join_index
if len(self) == 0 and how in ("right", "outer"):
join_index = other._shallow_copy()
if return_indexers:
lindexer = np.repeat(-1, len(join_index))
return join_index, lindexer, None
else:
return join_index
if self._join_precedence < other._join_precedence:
how = {"right": "left", "left": "right"}.get(how, how)
result = other.join(
self, how=how, level=level, return_indexers=return_indexers
)
if return_indexers:
x, y, z = result
result = x, z, y
return result
if not is_dtype_equal(self.dtype, other.dtype):
this = self.astype("O")
other = other.astype("O")
return this.join(other, how=how, return_indexers=return_indexers)
_validate_join_method(how)
if not self.is_unique and not other.is_unique:
return self._join_non_unique(
other, how=how, return_indexers=return_indexers
)
elif not self.is_unique or not other.is_unique:
if self.is_monotonic and other.is_monotonic:
return self._join_monotonic(
other, how=how, return_indexers=return_indexers
)
else:
return self._join_non_unique(
other, how=how, return_indexers=return_indexers
)
elif self.is_monotonic and other.is_monotonic:
try:
return self._join_monotonic(
other, how=how, return_indexers=return_indexers
)
except TypeError:
pass
if how == "left":
join_index = self
elif how == "right":
join_index = other
elif how == "inner":
# TODO: sort=False here for backwards compat. It may
# be better to use the sort parameter passed into join
join_index = self.intersection(other, sort=False)
elif how == "outer":
# TODO: sort=True here for backwards compat. It may
# be better to use the sort parameter passed into join
join_index = self.union(other)
if sort:
join_index = join_index.sort_values()
if return_indexers:
if join_index is self:
lindexer = None
else:
lindexer = self.get_indexer(join_index)
if join_index is other:
rindexer = None
else:
rindexer = other.get_indexer(join_index)
return join_index, lindexer, rindexer
else:
return join_index
def _join_multi(self, other, how, return_indexers=True):
from pandas.core.indexes.multi import MultiIndex
from pandas.core.reshape.merge import _restore_dropped_levels_multijoin
# figure out join names
self_names = set(com.not_none(*self.names))
other_names = set(com.not_none(*other.names))
overlap = self_names & other_names
# need at least 1 in common
if not overlap:
raise ValueError("cannot join with no overlapping index names")
self_is_mi = isinstance(self, ABCMultiIndex)
other_is_mi = isinstance(other, ABCMultiIndex)
if self_is_mi and other_is_mi:
# Drop the non-matching levels from left and right respectively
ldrop_names = list(self_names - overlap)
rdrop_names = list(other_names - overlap)
# if only the order differs
if not len(ldrop_names + rdrop_names):
self_jnlevels = self
other_jnlevels = other.reorder_levels(self.names)
else:
self_jnlevels = self.droplevel(ldrop_names)
other_jnlevels = other.droplevel(rdrop_names)
# Join left and right
# Join on same leveled multi-index frames is supported
join_idx, lidx, ridx = self_jnlevels.join(
other_jnlevels, how, return_indexers=True
)
# Restore the dropped levels
# Returned index level order is
# common levels, ldrop_names, rdrop_names
dropped_names = ldrop_names + rdrop_names
levels, codes, names = _restore_dropped_levels_multijoin(
self, other, dropped_names, join_idx, lidx, ridx
)
# Re-create the multi-index
multi_join_idx = MultiIndex(
levels=levels, codes=codes, names=names, verify_integrity=False
)
multi_join_idx = multi_join_idx.remove_unused_levels()
return multi_join_idx, lidx, ridx
jl = list(overlap)[0]
# Case where only one index is multi
# make the indices into mi's that match
flip_order = False
if self_is_mi:
self, other = other, self
flip_order = True
# flip if join method is right or left
how = {"right": "left", "left": "right"}.get(how, how)
level = other.names.index(jl)
result = self._join_level(
other, level, how=how, return_indexers=return_indexers
)
if flip_order:
if isinstance(result, tuple):
return result[0], result[2], result[1]
return result
def _join_non_unique(self, other, how="left", return_indexers=False):
from pandas.core.reshape.merge import _get_join_indexers
left_idx, right_idx = _get_join_indexers(
[self._ndarray_values], [other._ndarray_values], how=how, sort=True
)
left_idx = ensure_platform_int(left_idx)
right_idx = ensure_platform_int(right_idx)
join_index = np.asarray(self._ndarray_values.take(left_idx))
mask = left_idx == -1
np.putmask(join_index, mask, other._ndarray_values.take(right_idx))
join_index = self._wrap_joined_index(join_index, other)
if return_indexers:
return join_index, left_idx, right_idx
else:
return join_index
def _join_level(
self, other, level, how="left", return_indexers=False, keep_order=True
):
"""
The join method *only* affects the level of the resulting
MultiIndex. Otherwise it just exactly aligns the Index data to the
labels of the level in the MultiIndex.
If ```keep_order == True```, the order of the data indexed by the
MultiIndex will not be changed; otherwise, it will tie out
with `other`.
"""
from pandas.core.indexes.multi import MultiIndex
def _get_leaf_sorter(labels):
"""
Returns sorter for the inner most level while preserving the
order of higher levels.
"""
if labels[0].size == 0:
return np.empty(0, dtype="int64")
if len(labels) == 1:
lab = ensure_int64(labels[0])
sorter, _ = libalgos.groupsort_indexer(lab, 1 + lab.max())
return sorter
# find indexers of beginning of each set of
# same-key labels w.r.t all but last level
tic = labels[0][:-1] != labels[0][1:]
for lab in labels[1:-1]:
tic |= lab[:-1] != lab[1:]
starts = np.hstack(([True], tic, [True])).nonzero()[0]
lab = ensure_int64(labels[-1])
return lib.get_level_sorter(lab, ensure_int64(starts))
if isinstance(self, MultiIndex) and isinstance(other, MultiIndex):
raise TypeError("Join on level between two MultiIndex objects is ambiguous")
left, right = self, other
flip_order = not isinstance(self, MultiIndex)
if flip_order:
left, right = right, left
how = {"right": "left", "left": "right"}.get(how, how)
level = left._get_level_number(level)
old_level = left.levels[level]
if not right.is_unique:
raise NotImplementedError(
"Index._join_level on non-unique index is not implemented"
)
new_level, left_lev_indexer, right_lev_indexer = old_level.join(
right, how=how, return_indexers=True
)
if left_lev_indexer is None:
if keep_order or len(left) == 0:
left_indexer = None
join_index = left
else: # sort the leaves
left_indexer = _get_leaf_sorter(left.codes[: level + 1])
join_index = left[left_indexer]
else:
left_lev_indexer = ensure_int64(left_lev_indexer)
rev_indexer = lib.get_reverse_indexer(left_lev_indexer, len(old_level))
new_lev_codes = algos.take_nd(
rev_indexer, left.codes[level], allow_fill=False
)
new_codes = list(left.codes)
new_codes[level] = new_lev_codes
new_levels = list(left.levels)
new_levels[level] = new_level
if keep_order: # just drop missing values. o.w. keep order
left_indexer = np.arange(len(left), dtype=np.intp)
mask = new_lev_codes != -1
if not mask.all():
new_codes = [lab[mask] for lab in new_codes]
left_indexer = left_indexer[mask]
else: # tie out the order with other
if level == 0: # outer most level, take the fast route
ngroups = 1 + new_lev_codes.max()
left_indexer, counts = libalgos.groupsort_indexer(
new_lev_codes, ngroups
)
# missing values are placed first; drop them!
left_indexer = left_indexer[counts[0] :]
new_codes = [lab[left_indexer] for lab in new_codes]
else: # sort the leaves
mask = new_lev_codes != -1
mask_all = mask.all()
if not mask_all:
new_codes = [lab[mask] for lab in new_codes]
left_indexer = _get_leaf_sorter(new_codes[: level + 1])
new_codes = [lab[left_indexer] for lab in new_codes]
# left_indexers are w.r.t masked frame.
# reverse to original frame!
if not mask_all:
left_indexer = mask.nonzero()[0][left_indexer]
join_index = MultiIndex(
levels=new_levels,
codes=new_codes,
names=left.names,
verify_integrity=False,
)
if right_lev_indexer is not None:
right_indexer = algos.take_nd(
right_lev_indexer, join_index.codes[level], allow_fill=False
)
else:
right_indexer = join_index.codes[level]
if flip_order:
left_indexer, right_indexer = right_indexer, left_indexer
if return_indexers:
left_indexer = (
None if left_indexer is None else ensure_platform_int(left_indexer)
)
right_indexer = (
None if right_indexer is None else ensure_platform_int(right_indexer)
)
return join_index, left_indexer, right_indexer
else:
return join_index
def _join_monotonic(self, other, how="left", return_indexers=False):
if self.equals(other):
ret_index = other if how == "right" else self
if return_indexers:
return ret_index, None, None
else:
return ret_index
sv = self._ndarray_values
ov = other._ndarray_values
if self.is_unique and other.is_unique:
# We can perform much better than the general case
if how == "left":
join_index = self
lidx = None
ridx = self._left_indexer_unique(sv, ov)
elif how == "right":
join_index = other
lidx = self._left_indexer_unique(ov, sv)
ridx = None
elif how == "inner":
join_index, lidx, ridx = self._inner_indexer(sv, ov)
join_index = self._wrap_joined_index(join_index, other)
elif how == "outer":
join_index, lidx, ridx = self._outer_indexer(sv, ov)
join_index = self._wrap_joined_index(join_index, other)
else:
if how == "left":
join_index, lidx, ridx = self._left_indexer(sv, ov)
elif how == "right":
join_index, ridx, lidx = self._left_indexer(ov, sv)
elif how == "inner":
join_index, lidx, ridx = self._inner_indexer(sv, ov)
elif how == "outer":
join_index, lidx, ridx = self._outer_indexer(sv, ov)
join_index = self._wrap_joined_index(join_index, other)
if return_indexers:
lidx = None if lidx is None else ensure_platform_int(lidx)
ridx = None if ridx is None else ensure_platform_int(ridx)
return join_index, lidx, ridx
else:
return join_index
def _wrap_joined_index(self, joined, other):
name = get_op_result_name(self, other)
return Index(joined, name=name)
# --------------------------------------------------------------------
# Uncategorized Methods
@property
def values(self) -> np.ndarray:
"""
Return an array representing the data in the Index.
.. warning::
We recommend using :attr:`Index.array` or
:meth:`Index.to_numpy`, depending on whether you need
a reference to the underlying data or a NumPy array.
Returns
-------
array: numpy.ndarray or ExtensionArray
See Also
--------
Index.array : Reference to the underlying data.
Index.to_numpy : A NumPy array representing the underlying data.
"""
return self._data.view(np.ndarray)
@cache_readonly
@Appender(IndexOpsMixin.array.__doc__) # type: ignore
def array(self) -> ExtensionArray:
array = self._data
if isinstance(array, np.ndarray):
from pandas.core.arrays.numpy_ import PandasArray
array = PandasArray(array)
return array
@property
def _values(self) -> Union[ExtensionArray, np.ndarray]:
"""
The best array representation.
This is an ndarray or ExtensionArray. This differs from
``_ndarray_values``, which always returns an ndarray.
Both ``_values`` and ``_ndarray_values`` are consistent between
``Series`` and ``Index`` (except for datetime64[ns], which returns
a DatetimeArray for _values on the Index, but ndarray[M8ns] on the
Series).
It may differ from the public '.values' method.
index | values | _values | _ndarray_values |
----------------- | --------------- | ------------- | --------------- |
Index | ndarray | ndarray | ndarray |
CategoricalIndex | Categorical | Categorical | ndarray[int] |
DatetimeIndex | ndarray[M8ns] | DatetimeArray | ndarray[M8ns] |
DatetimeIndex[tz] | ndarray[M8ns] | DatetimeArray | ndarray[M8ns] |
PeriodIndex | ndarray[object] | PeriodArray | ndarray[int] |
IntervalIndex | IntervalArray | IntervalArray | ndarray[object] |
See Also
--------
values
_ndarray_values
"""
return self._data
def _internal_get_values(self) -> np.ndarray:
"""
Return `Index` data as an `numpy.ndarray`.
Returns
-------
numpy.ndarray
A one-dimensional numpy array of the `Index` values.
See Also
--------
Index.values : The attribute that _internal_get_values wraps.
Examples
--------
Getting the `Index` values of a `DataFrame`:
>>> df = pd.DataFrame([[1, 2, 3], [4, 5, 6], [7, 8, 9]],
... index=['a', 'b', 'c'], columns=['A', 'B', 'C'])
>>> df
A B C
a 1 2 3
b 4 5 6
c 7 8 9
>>> df.index._internal_get_values()
array(['a', 'b', 'c'], dtype=object)
Standalone `Index` values:
>>> idx = pd.Index(['1', '2', '3'])
>>> idx._internal_get_values()
array(['1', '2', '3'], dtype=object)
`MultiIndex` arrays also have only one dimension:
>>> midx = pd.MultiIndex.from_arrays([[1, 2, 3], ['a', 'b', 'c']],
... names=('number', 'letter'))
>>> midx._internal_get_values()
array([(1, 'a'), (2, 'b'), (3, 'c')], dtype=object)
>>> midx._internal_get_values().ndim
1
"""
return self.values
@Appender(IndexOpsMixin.memory_usage.__doc__)
def memory_usage(self, deep: bool = False) -> int:
result = super().memory_usage(deep=deep)
# include our engine hashtable
result += self._engine.sizeof(deep=deep)
return result
def where(self, cond, other=None):
"""
Return an Index of same shape as self and whose corresponding
entries are from self where cond is True and otherwise are from
other.
Parameters
----------
cond : bool array-like with the same length as self
other : scalar, or array-like
Returns
-------
Index
"""
if other is None:
other = self._na_value
dtype = self.dtype
values = self.values
if is_bool(other) or is_bool_dtype(other):
# bools force casting
values = values.astype(object)
dtype = None
values = np.where(cond, values, other)
if self._is_numeric_dtype and np.any(isna(values)):
# We can't coerce to the numeric dtype of "self" (unless
# it's float) if there are NaN values in our output.
dtype = None
return self._shallow_copy_with_infer(values, dtype=dtype)
# construction helpers
@classmethod
def _scalar_data_error(cls, data):
# We return the TypeError so that we can raise it from the constructor
# in order to keep mypy happy
return TypeError(
f"{cls.__name__}(...) must be called with a collection of some "
f"kind, {repr(data)} was passed"
)
@classmethod
def _string_data_error(cls, data):
raise TypeError(
"String dtype not supported, you may need "
"to explicitly cast to a numeric type"
)
def _coerce_scalar_to_index(self, item):
"""
We need to coerce a scalar to a compat for our index type.
Parameters
----------
item : scalar item to coerce
"""
dtype = self.dtype
if self._is_numeric_dtype and isna(item):
# We can't coerce to the numeric dtype of "self" (unless
# it's float) if there are NaN values in our output.
dtype = None
return Index([item], dtype=dtype, **self._get_attributes_dict())
def _to_safe_for_reshape(self):
"""
Convert to object if we are a categorical.
"""
return self
def _convert_for_op(self, value):
"""
Convert value to be insertable to ndarray.
"""
return value
def _assert_can_do_op(self, value):
"""
Check value is valid for scalar op.
"""
if not is_scalar(value):
raise TypeError(f"'value' must be a scalar, passed: {type(value).__name__}")
@property
def _has_complex_internals(self) -> bool:
"""
Indicates if an index is not directly backed by a numpy array
"""
# used to avoid libreduction code paths, which raise or require conversion
return False
def _is_memory_usage_qualified(self) -> bool:
"""
Return a boolean if we need a qualified .info display.
"""
return self.is_object()
def is_type_compatible(self, kind) -> bool:
"""
Whether the index type is compatible with the provided type.
"""
return kind == self.inferred_type
def __contains__(self, key: Any) -> bool:
"""
Return a boolean indicating whether the provided key is in the index.
Parameters
----------
key : label
The key to check if it is present in the index.
Returns
-------
bool
Whether the key search is in the index.
Raises
------
TypeError
If the key is not hashable.
See Also
--------
Index.isin : Returns an ndarray of boolean dtype indicating whether the
list-like key is in the index.
Examples
--------
>>> idx = pd.Index([1, 2, 3, 4])
>>> idx
Int64Index([1, 2, 3, 4], dtype='int64')
>>> 2 in idx
True
>>> 6 in idx
False
"""
hash(key)
try:
return key in self._engine
except (OverflowError, TypeError, ValueError):
return False
def __hash__(self):
raise TypeError(f"unhashable type: {repr(type(self).__name__)}")
def __setitem__(self, key, value):
raise TypeError("Index does not support mutable operations")
def __getitem__(self, key):
"""
Override numpy.ndarray's __getitem__ method to work as desired.
This function adds lists and Series as valid boolean indexers
(ndarrays only supports ndarray with dtype=bool).
If resulting ndim != 1, plain ndarray is returned instead of
corresponding `Index` subclass.
"""
# There's no custom logic to be implemented in __getslice__, so it's
# not overloaded intentionally.
getitem = self._data.__getitem__
promote = self._shallow_copy
if is_scalar(key):
key = com.cast_scalar_indexer(key)
return getitem(key)
if isinstance(key, slice):
# This case is separated from the conditional above to avoid
# pessimization of basic indexing.
return promote(getitem(key))
if com.is_bool_indexer(key):
key = np.asarray(key, dtype=bool)
key = com.values_from_object(key)
result = getitem(key)
if not is_scalar(result):
if np.ndim(result) > 1:
deprecate_ndim_indexing(result)
return result
return promote(result)
else:
return result
def _can_hold_identifiers_and_holds_name(self, name) -> bool:
"""
Faster check for ``name in self`` when we know `name` is a Python
identifier (e.g. in NDFrame.__getattr__, which hits this to support
. key lookup). For indexes that can't hold identifiers (everything
but object & categorical) we just return False.
https://github.com/pandas-dev/pandas/issues/19764
"""
if self.is_object() or self.is_categorical():
return name in self
return False
def append(self, other):
"""
Append a collection of Index options together.
Parameters
----------
other : Index or list/tuple of indices
Returns
-------
appended : Index
"""
to_concat = [self]
if isinstance(other, (list, tuple)):
to_concat = to_concat + list(other)
else:
to_concat.append(other)
for obj in to_concat:
if not isinstance(obj, Index):
raise TypeError("all inputs must be Index")
names = {obj.name for obj in to_concat}
name = None if len(names) > 1 else self.name
return self._concat(to_concat, name)
def _concat(self, to_concat, name):
typs = _concat.get_dtype_kinds(to_concat)
if len(typs) == 1:
return self._concat_same_dtype(to_concat, name=name)
return Index._concat_same_dtype(self, to_concat, name=name)
def _concat_same_dtype(self, to_concat, name):
"""
Concatenate to_concat which has the same class.
"""
# must be overridden in specific classes
klasses = (
ABCDatetimeIndex,
ABCTimedeltaIndex,
ABCPeriodIndex,
ExtensionArray,
ABCIntervalIndex,
)
to_concat = [
x.astype(object) if isinstance(x, klasses) else x for x in to_concat
]
self = to_concat[0]
attribs = self._get_attributes_dict()
attribs["name"] = name
to_concat = [x._values if isinstance(x, Index) else x for x in to_concat]
return self._shallow_copy_with_infer(np.concatenate(to_concat), **attribs)
def putmask(self, mask, value):
"""
Return a new Index of the values set with the mask.
Returns
-------
Index
See Also
--------
numpy.ndarray.putmask
"""
values = self.values.copy()
try:
np.putmask(values, mask, self._convert_for_op(value))
return self._shallow_copy(values)
except (ValueError, TypeError) as err:
if is_object_dtype(self):
raise err
# coerces to object
return self.astype(object).putmask(mask, value)
def equals(self, other) -> bool:
"""
Determine if two Index objects contain the same elements.
Returns
-------
bool
True if "other" is an Index and it has the same elements as calling
index; False otherwise.
"""
if self.is_(other):
return True
if not isinstance(other, Index):
return False
if is_object_dtype(self) and not is_object_dtype(other):
# if other is not object, use other's logic for coercion
return other.equals(self)
if isinstance(other, ABCMultiIndex):
# d-level MultiIndex can equal d-tuple Index
if not is_object_dtype(self.dtype):
if self.nlevels != other.nlevels:
return False
return array_equivalent(
com.values_from_object(self), com.values_from_object(other)
)
def identical(self, other) -> bool:
"""
Similar to equals, but check that other comparable attributes are
also equal.
Returns
-------
bool
If two Index objects have equal elements and same type True,
otherwise False.
"""
return (
self.equals(other)
and all(
(
getattr(self, c, None) == getattr(other, c, None)
for c in self._comparables
)
)
and type(self) == type(other)
)
def asof(self, label):
"""
Return the label from the index, or, if not present, the previous one.
Assuming that the index is sorted, return the passed index label if it
is in the index, or return the previous index label if the passed one
is not in the index.
Parameters
----------
label : object
The label up to which the method returns the latest index label.
Returns
-------
object
The passed label if it is in the index. The previous label if the
passed label is not in the sorted index or `NaN` if there is no
such label.
See Also
--------
Series.asof : Return the latest value in a Series up to the
passed index.
merge_asof : Perform an asof merge (similar to left join but it
matches on nearest key rather than equal key).
Index.get_loc : An `asof` is a thin wrapper around `get_loc`
with method='pad'.
Examples
--------
`Index.asof` returns the latest index label up to the passed label.
>>> idx = pd.Index(['2013-12-31', '2014-01-02', '2014-01-03'])
>>> idx.asof('2014-01-01')
'2013-12-31'
If the label is in the index, the method returns the passed label.
>>> idx.asof('2014-01-02')
'2014-01-02'
If all of the labels in the index are later than the passed label,
NaN is returned.
>>> idx.asof('1999-01-02')
nan
If the index is not sorted, an error is raised.
>>> idx_not_sorted = pd.Index(['2013-12-31', '2015-01-02',
... '2014-01-03'])
>>> idx_not_sorted.asof('2013-12-31')
Traceback (most recent call last):
ValueError: index must be monotonic increasing or decreasing
"""
try:
loc = self.get_loc(label, method="pad")
except KeyError:
return self._na_value
else:
if isinstance(loc, slice):
loc = loc.indices(len(self))[-1]
return self[loc]
def asof_locs(self, where, mask):
"""
Find the locations (indices) of the labels from the index for
every entry in the `where` argument.
As in the `asof` function, if the label (a particular entry in
`where`) is not in the index, the latest index label up to the
passed label is chosen and its index returned.
If all of the labels in the index are later than a label in `where`,
-1 is returned.
`mask` is used to ignore NA values in the index during calculation.
Parameters
----------
where : Index
An Index consisting of an array of timestamps.
mask : array-like
Array of booleans denoting where values in the original
data are not NA.
Returns
-------
numpy.ndarray
An array of locations (indices) of the labels from the Index
which correspond to the return values of the `asof` function
for every element in `where`.
"""
locs = self.values[mask].searchsorted(where.values, side="right")
locs = np.where(locs > 0, locs - 1, 0)
result = np.arange(len(self))[mask].take(locs)
first = mask.argmax()
result[(locs == 0) & (where.values < self.values[first])] = -1
return result
def sort_values(self, return_indexer: bool = False, ascending: bool = True):
"""
Return a sorted copy of the index.
Return a sorted copy of the index, and optionally return the indices
that sorted the index itself.
Parameters
----------
return_indexer : bool, default False
Should the indices that would sort the index be returned.
ascending : bool, default True
Should the index values be sorted in an ascending order.
Returns
-------
sorted_index : pandas.Index
Sorted copy of the index.
indexer : numpy.ndarray, optional
The indices that the index itself was sorted by.
See Also
--------
Series.sort_values : Sort values of a Series.
DataFrame.sort_values : Sort values in a DataFrame.
Examples
--------
>>> idx = pd.Index([10, 100, 1, 1000])
>>> idx
Int64Index([10, 100, 1, 1000], dtype='int64')
Sort values in ascending order (default behavior).
>>> idx.sort_values()
Int64Index([1, 10, 100, 1000], dtype='int64')
Sort values in descending order, and also get the indices `idx` was
sorted by.
>>> idx.sort_values(ascending=False, return_indexer=True)
(Int64Index([1000, 100, 10, 1], dtype='int64'), array([3, 1, 0, 2]))
"""
_as = self.argsort()
if not ascending:
_as = _as[::-1]
sorted_index = self.take(_as)
if return_indexer:
return sorted_index, _as
else:
return sorted_index
def sort(self, *args, **kwargs):
"""
Use sort_values instead.
"""
raise TypeError("cannot sort an Index object in-place, use sort_values instead")
def shift(self, periods=1, freq=None):
"""
Shift index by desired number of time frequency increments.
This method is for shifting the values of datetime-like indexes
by a specified time increment a given number of times.
Parameters
----------
periods : int, default 1
Number of periods (or increments) to shift by,
can be positive or negative.
freq : pandas.DateOffset, pandas.Timedelta or str, optional
Frequency increment to shift by.
If None, the index is shifted by its own `freq` attribute.
Offset aliases are valid strings, e.g., 'D', 'W', 'M' etc.
Returns
-------
pandas.Index
Shifted index.
See Also
--------
Series.shift : Shift values of Series.
Notes
-----
This method is only implemented for datetime-like index classes,
i.e., DatetimeIndex, PeriodIndex and TimedeltaIndex.
Examples
--------
Put the first 5 month starts of 2011 into an index.
>>> month_starts = pd.date_range('1/1/2011', periods=5, freq='MS')
>>> month_starts
DatetimeIndex(['2011-01-01', '2011-02-01', '2011-03-01', '2011-04-01',
'2011-05-01'],
dtype='datetime64[ns]', freq='MS')
Shift the index by 10 days.
>>> month_starts.shift(10, freq='D')
DatetimeIndex(['2011-01-11', '2011-02-11', '2011-03-11', '2011-04-11',
'2011-05-11'],
dtype='datetime64[ns]', freq=None)
The default value of `freq` is the `freq` attribute of the index,
which is 'MS' (month start) in this example.
>>> month_starts.shift(10)
DatetimeIndex(['2011-11-01', '2011-12-01', '2012-01-01', '2012-02-01',
'2012-03-01'],
dtype='datetime64[ns]', freq='MS')
"""
raise NotImplementedError(f"Not supported for type {type(self).__name__}")
def argsort(self, *args, **kwargs) -> np.ndarray:
"""
Return the integer indices that would sort the index.
Parameters
----------
*args
Passed to `numpy.ndarray.argsort`.
**kwargs
Passed to `numpy.ndarray.argsort`.
Returns
-------
numpy.ndarray
Integer indices that would sort the index if used as
an indexer.
See Also
--------
numpy.argsort : Similar method for NumPy arrays.
Index.sort_values : Return sorted copy of Index.
Examples
--------
>>> idx = pd.Index(['b', 'a', 'd', 'c'])
>>> idx
Index(['b', 'a', 'd', 'c'], dtype='object')
>>> order = idx.argsort()
>>> order
array([1, 0, 3, 2])
>>> idx[order]
Index(['a', 'b', 'c', 'd'], dtype='object')
"""
result = self.asi8
if result is None:
result = np.array(self)
return result.argsort(*args, **kwargs)
def get_value(self, series: "Series", key):
"""
Fast lookup of value from 1-dimensional ndarray. Only use this if you
know what you're doing.
Returns
-------
scalar or Series
"""
if not is_scalar(key):
# if key is not a scalar, directly raise an error (the code below
# would convert to numpy arrays and raise later any way) - GH29926
raise InvalidIndexError(key)
try:
# GH 20882, 21257
# First try to convert the key to a location
# If that fails, raise a KeyError if an integer
# index, otherwise, see if key is an integer, and
# try that
loc = self.get_loc(key)
except KeyError:
if not self._should_fallback_to_positional():
raise
elif is_integer(key):
# If the Index cannot hold integer, then this is unambiguously
# a locational lookup.
loc = key
else:
raise
return self._get_values_for_loc(series, loc, key)
def _should_fallback_to_positional(self) -> bool:
"""
If an integer key is not found, should we fall back to positional indexing?
"""
if len(self) > 0 and (self.holds_integer() or self.is_boolean()):
return False
return True
def _get_values_for_loc(self, series: "Series", loc, key):
"""
Do a positional lookup on the given Series, returning either a scalar
or a Series.
Assumes that `series.index is self`
key is included for MultiIndex compat.
"""
if is_integer(loc):
return series._values[loc]
return series.iloc[loc]
def set_value(self, arr, key, value):
"""
Fast lookup of value from 1-dimensional ndarray.
.. deprecated:: 1.0
Notes
-----
Only use this if you know what you're doing.
"""
warnings.warn(
(
"The 'set_value' method is deprecated, and "
"will be removed in a future version."
),
FutureWarning,
stacklevel=2,
)
loc = self._engine.get_loc(key)
validate_numeric_casting(arr.dtype, value)
arr[loc] = value
_index_shared_docs[
"get_indexer_non_unique"
] = """
Compute indexer and mask for new index given the current index. The
indexer should be then used as an input to ndarray.take to align the
current data to the new index.
Parameters
----------
target : %(target_klass)s
Returns
-------
indexer : ndarray of int
Integers from 0 to n - 1 indicating that the index at these
positions matches the corresponding target values. Missing values
in the target are marked by -1.
missing : ndarray of int
An indexer into the target of the values not found.
These correspond to the -1 in the indexer array.
"""
@Appender(_index_shared_docs["get_indexer_non_unique"] % _index_doc_kwargs)
def get_indexer_non_unique(self, target):
target = ensure_index(target)
pself, ptarget = self._maybe_promote(target)
if pself is not self or ptarget is not target:
return pself.get_indexer_non_unique(ptarget)
if is_categorical(target):
tgt_values = np.asarray(target)
elif self.is_all_dates and target.is_all_dates: # GH 30399
tgt_values = target.asi8
else:
tgt_values = target._ndarray_values
indexer, missing = self._engine.get_indexer_non_unique(tgt_values)
return ensure_platform_int(indexer), missing
def get_indexer_for(self, target, **kwargs):
"""
Guaranteed return of an indexer even when non-unique.
This dispatches to get_indexer or get_indexer_non_unique
as appropriate.
Returns
-------
numpy.ndarray
List of indices.
"""
if self.is_unique:
return self.get_indexer(target, **kwargs)
indexer, _ = self.get_indexer_non_unique(target, **kwargs)
return indexer
def _maybe_promote(self, other):
# A hack, but it works
if self.inferred_type == "date" and isinstance(other, ABCDatetimeIndex):
return type(other)(self), other
elif self.inferred_type == "boolean":
if not is_object_dtype(self.dtype):
return self.astype("object"), other.astype("object")
return self, other
def groupby(self, values) -> PrettyDict[Hashable, np.ndarray]:
"""
Group the index labels by a given array of values.
Parameters
----------
values : array
Values used to determine the groups.
Returns
-------
dict
{group name -> group labels}
"""
# TODO: if we are a MultiIndex, we can do better
# that converting to tuples
if isinstance(values, ABCMultiIndex):
values = values.values
values = ensure_categorical(values)
result = values._reverse_indexer()
# map to the label
result = {k: self.take(v) for k, v in result.items()}
return PrettyDict(result)
def map(self, mapper, na_action=None):
"""
Map values using input correspondence (a dict, Series, or function).
Parameters
----------
mapper : function, dict, or Series
Mapping correspondence.
na_action : {None, 'ignore'}
If 'ignore', propagate NA values, without passing them to the
mapping correspondence.
Returns
-------
applied : Union[Index, MultiIndex], inferred
The output of the mapping function applied to the index.
If the function returns a tuple with more than one element
a MultiIndex will be returned.
"""
from pandas.core.indexes.multi import MultiIndex
new_values = super()._map_values(mapper, na_action=na_action)
attributes = self._get_attributes_dict()
# we can return a MultiIndex
if new_values.size and isinstance(new_values[0], tuple):
if isinstance(self, MultiIndex):
names = self.names
elif attributes.get("name"):
names = [attributes.get("name")] * len(new_values[0])
else:
names = None
return MultiIndex.from_tuples(new_values, names=names)
attributes["copy"] = False
if not new_values.size:
# empty
attributes["dtype"] = self.dtype
return Index(new_values, **attributes)
def isin(self, values, level=None):
"""
Return a boolean array where the index values are in `values`.
Compute boolean array of whether each index value is found in the
passed set of values. The length of the returned boolean array matches
the length of the index.
Parameters
----------
values : set or list-like
Sought values.
level : str or int, optional
Name or position of the index level to use (if the index is a
`MultiIndex`).
Returns
-------
is_contained : ndarray
NumPy array of boolean values.
See Also
--------
Series.isin : Same for Series.
DataFrame.isin : Same method for DataFrames.
Notes
-----
In the case of `MultiIndex` you must either specify `values` as a
list-like object containing tuples that are the same length as the
number of levels, or specify `level`. Otherwise it will raise a
``ValueError``.
If `level` is specified:
- if it is the name of one *and only one* index level, use that level;
- otherwise it should be a number indicating level position.
Examples
--------
>>> idx = pd.Index([1,2,3])
>>> idx
Int64Index([1, 2, 3], dtype='int64')
Check whether each index value in a list of values.
>>> idx.isin([1, 4])
array([ True, False, False])
>>> midx = pd.MultiIndex.from_arrays([[1,2,3],
... ['red', 'blue', 'green']],
... names=('number', 'color'))
>>> midx
MultiIndex(levels=[[1, 2, 3], ['blue', 'green', 'red']],
codes=[[0, 1, 2], [2, 0, 1]],
names=['number', 'color'])
Check whether the strings in the 'color' level of the MultiIndex
are in a list of colors.
>>> midx.isin(['red', 'orange', 'yellow'], level='color')
array([ True, False, False])
To check across the levels of a MultiIndex, pass a list of tuples:
>>> midx.isin([(1, 'red'), (3, 'red')])
array([ True, False, False])
For a DatetimeIndex, string values in `values` are converted to
Timestamps.
>>> dates = ['2000-03-11', '2000-03-12', '2000-03-13']
>>> dti = pd.to_datetime(dates)
>>> dti
DatetimeIndex(['2000-03-11', '2000-03-12', '2000-03-13'],
dtype='datetime64[ns]', freq=None)
>>> dti.isin(['2000-03-11'])
array([ True, False, False])
"""
if level is not None:
self._validate_index_level(level)
return algos.isin(self, values)
def _get_string_slice(self, key: str_t, use_lhs: bool = True, use_rhs: bool = True):
# this is for partial string indexing,
# overridden in DatetimeIndex, TimedeltaIndex and PeriodIndex
raise NotImplementedError
def slice_indexer(self, start=None, end=None, step=None, kind=None):
"""
For an ordered or unique index, compute the slice indexer for input
labels and step.
Parameters
----------
start : label, default None
If None, defaults to the beginning.
end : label, default None
If None, defaults to the end.
step : int, default None
kind : str, default None
Returns
-------
indexer : slice
Raises
------
KeyError : If key does not exist, or key is not unique and index is
not ordered.
Notes
-----
This function assumes that the data is sorted, so use at your own peril
Examples
--------
This is a method on all index types. For example you can do:
>>> idx = pd.Index(list('abcd'))
>>> idx.slice_indexer(start='b', end='c')
slice(1, 3)
>>> idx = pd.MultiIndex.from_arrays([list('abcd'), list('efgh')])
>>> idx.slice_indexer(start='b', end=('c', 'g'))
slice(1, 3)
"""
start_slice, end_slice = self.slice_locs(start, end, step=step, kind=kind)
# return a slice
if not is_scalar(start_slice):
raise AssertionError("Start slice bound is non-scalar")
if not is_scalar(end_slice):
raise AssertionError("End slice bound is non-scalar")
return slice(start_slice, end_slice, step)
def _maybe_cast_indexer(self, key):
"""
If we have a float key and are not a floating index, then try to cast
to an int if equivalent.
"""
if not self.is_floating():
return com.cast_scalar_indexer(key)
return key
def _validate_indexer(self, form: str_t, key, kind: str_t):
"""
If we are positional indexer, validate that we have appropriate
typed bounds must be an integer.
"""
assert kind in ["getitem", "iloc"]
if key is None:
pass
elif is_integer(key):
pass
else:
self._invalid_indexer(form, key)
def _maybe_cast_slice_bound(self, label, side: str_t, kind):
"""
This function should be overloaded in subclasses that allow non-trivial
casting on label-slice bounds, e.g. datetime-like indices allowing
strings containing formatted datetimes.
Parameters
----------
label : object
side : {'left', 'right'}
kind : {'loc', 'getitem'} or None
Returns
-------
label : object
Notes
-----
Value of `side` parameter should be validated in caller.
"""
assert kind in ["loc", "getitem", None]
# We are a plain index here (sub-class override this method if they
# wish to have special treatment for floats/ints, e.g. Float64Index and
# datetimelike Indexes
# reject them
if is_float(label):
self._invalid_indexer("slice", label)
# we are trying to find integer bounds on a non-integer based index
# this is rejected (generally .loc gets you here)
elif is_integer(label):
self._invalid_indexer("slice", label)
return label
def _searchsorted_monotonic(self, label, side="left"):
if self.is_monotonic_increasing:
return self.searchsorted(label, side=side)
elif self.is_monotonic_decreasing:
# np.searchsorted expects ascending sort order, have to reverse
# everything for it to work (element ordering, search side and
# resulting value).
pos = self[::-1].searchsorted(
label, side="right" if side == "left" else "left"
)
return len(self) - pos
raise ValueError("index must be monotonic increasing or decreasing")
def get_slice_bound(self, label, side: str_t, kind) -> int:
"""
Calculate slice bound that corresponds to given label.
Returns leftmost (one-past-the-rightmost if ``side=='right'``) position
of given label.
Parameters
----------
label : object
side : {'left', 'right'}
kind : {'loc', 'getitem'} or None
Returns
-------
int
Index of label.
"""
assert kind in ["loc", "getitem", None]
if side not in ("left", "right"):
raise ValueError(
"Invalid value for side kwarg, must be either "
f"'left' or 'right': {side}"
)
original_label = label
# For datetime indices label may be a string that has to be converted
# to datetime boundary according to its resolution.
label = self._maybe_cast_slice_bound(label, side, kind)
# we need to look up the label
try:
slc = self.get_loc(label)
except KeyError as err:
try:
return self._searchsorted_monotonic(label, side)
except ValueError:
# raise the original KeyError
raise err
if isinstance(slc, np.ndarray):
# get_loc may return a boolean array or an array of indices, which
# is OK as long as they are representable by a slice.
if is_bool_dtype(slc):
slc = lib.maybe_booleans_to_slice(slc.view("u1"))
else:
slc = lib.maybe_indices_to_slice(slc.astype("i8"), len(self))
if isinstance(slc, np.ndarray):
raise KeyError(
f"Cannot get {side} slice bound for non-unique "
f"label: {repr(original_label)}"
)
if isinstance(slc, slice):
if side == "left":
return slc.start
else:
return slc.stop
else:
if side == "right":
return slc + 1
else:
return slc
def slice_locs(self, start=None, end=None, step=None, kind=None):
"""
Compute slice locations for input labels.
Parameters
----------
start : label, default None
If None, defaults to the beginning.
end : label, default None
If None, defaults to the end.
step : int, defaults None
If None, defaults to 1.
kind : {'loc', 'getitem'} or None
Returns
-------
start, end : int
See Also
--------
Index.get_loc : Get location for a single label.
Notes
-----
This method only works if the index is monotonic or unique.
Examples
--------
>>> idx = pd.Index(list('abcd'))
>>> idx.slice_locs(start='b', end='c')
(1, 3)
"""
inc = step is None or step >= 0
if not inc:
# If it's a reverse slice, temporarily swap bounds.
start, end = end, start
# GH 16785: If start and end happen to be date strings with UTC offsets
# attempt to parse and check that the offsets are the same
if isinstance(start, (str, datetime)) and isinstance(end, (str, datetime)):
try:
ts_start = Timestamp(start)
ts_end = Timestamp(end)
except (ValueError, TypeError):
pass
else:
if not tz_compare(ts_start.tzinfo, ts_end.tzinfo):
raise ValueError("Both dates must have the same UTC offset")
start_slice = None
if start is not None:
start_slice = self.get_slice_bound(start, "left", kind)
if start_slice is None:
start_slice = 0
end_slice = None
if end is not None:
end_slice = self.get_slice_bound(end, "right", kind)
if end_slice is None:
end_slice = len(self)
if not inc:
# Bounds at this moment are swapped, swap them back and shift by 1.
#
# slice_locs('B', 'A', step=-1): s='B', e='A'
#
# s='A' e='B'
# AFTER SWAP: | |
# v ------------------> V
# -----------------------------------
# | | |A|A|A|A| | | | | |B|B| | | | |
# -----------------------------------
# ^ <------------------ ^
# SHOULD BE: | |
# end=s-1 start=e-1
#
end_slice, start_slice = start_slice - 1, end_slice - 1
# i == -1 triggers ``len(self) + i`` selection that points to the
# last element, not before-the-first one, subtracting len(self)
# compensates that.
if end_slice == -1:
end_slice -= len(self)
if start_slice == -1:
start_slice -= len(self)
return start_slice, end_slice
def delete(self, loc):
"""
Make new Index with passed location(-s) deleted.
Parameters
----------
loc : int or list of int
Location of item(-s) which will be deleted.
Use a list of locations to delete more than one value at the same time.
Returns
-------
Index
New Index with passed location(-s) deleted.
See Also
--------
numpy.delete : Delete any rows and column from NumPy array (ndarray).
Examples
--------
>>> idx = pd.Index(['a', 'b', 'c'])
>>> idx.delete(1)
Index(['a', 'c'], dtype='object')
>>> idx = pd.Index(['a', 'b', 'c'])
>>> idx.delete([0, 2])
Index(['b'], dtype='object')
"""
return self._shallow_copy(np.delete(self._data, loc))
def insert(self, loc: int, item):
"""
Make new Index inserting new item at location.
Follows Python list.append semantics for negative values.
Parameters
----------
loc : int
item : object
Returns
-------
new_index : Index
"""
_self = np.asarray(self)
item = self._coerce_scalar_to_index(item)._ndarray_values
idx = np.concatenate((_self[:loc], item, _self[loc:]))
return self._shallow_copy_with_infer(idx)
def drop(self, labels, errors: str_t = "raise"):
"""
Make new Index with passed list of labels deleted.
Parameters
----------
labels : array-like
errors : {'ignore', 'raise'}, default 'raise'
If 'ignore', suppress error and existing labels are dropped.
Returns
-------
dropped : Index
Raises
------
KeyError
If not all of the labels are found in the selected axis
"""
arr_dtype = "object" if self.dtype == "object" else None
labels = com.index_labels_to_array(labels, dtype=arr_dtype)
indexer = self.get_indexer(labels)
mask = indexer == -1
if mask.any():
if errors != "ignore":
raise KeyError(f"{labels[mask]} not found in axis")
indexer = indexer[~mask]
return self.delete(indexer)
# --------------------------------------------------------------------
# Generated Arithmetic, Comparison, and Unary Methods
@classmethod
def _add_comparison_methods(cls):
"""
Add in comparison methods.
"""
cls.__eq__ = _make_comparison_op(operator.eq, cls)
cls.__ne__ = _make_comparison_op(operator.ne, cls)
cls.__lt__ = _make_comparison_op(operator.lt, cls)
cls.__gt__ = _make_comparison_op(operator.gt, cls)
cls.__le__ = _make_comparison_op(operator.le, cls)
cls.__ge__ = _make_comparison_op(operator.ge, cls)
@classmethod
def _add_numeric_methods_add_sub_disabled(cls):
"""
Add in the numeric add/sub methods to disable.
"""
cls.__add__ = make_invalid_op("__add__")
cls.__radd__ = make_invalid_op("__radd__")
cls.__iadd__ = make_invalid_op("__iadd__")
cls.__sub__ = make_invalid_op("__sub__")
cls.__rsub__ = make_invalid_op("__rsub__")
cls.__isub__ = make_invalid_op("__isub__")
@classmethod
def _add_numeric_methods_disabled(cls):
"""
Add in numeric methods to disable other than add/sub.
"""
cls.__pow__ = make_invalid_op("__pow__")
cls.__rpow__ = make_invalid_op("__rpow__")
cls.__mul__ = make_invalid_op("__mul__")
cls.__rmul__ = make_invalid_op("__rmul__")
cls.__floordiv__ = make_invalid_op("__floordiv__")
cls.__rfloordiv__ = make_invalid_op("__rfloordiv__")
cls.__truediv__ = make_invalid_op("__truediv__")
cls.__rtruediv__ = make_invalid_op("__rtruediv__")
cls.__mod__ = make_invalid_op("__mod__")
cls.__divmod__ = make_invalid_op("__divmod__")
cls.__neg__ = make_invalid_op("__neg__")
cls.__pos__ = make_invalid_op("__pos__")
cls.__abs__ = make_invalid_op("__abs__")
cls.__inv__ = make_invalid_op("__inv__")
@classmethod
def _add_numeric_methods_binary(cls):
"""
Add in numeric methods.
"""
cls.__add__ = _make_arithmetic_op(operator.add, cls)
cls.__radd__ = _make_arithmetic_op(ops.radd, cls)
cls.__sub__ = _make_arithmetic_op(operator.sub, cls)
cls.__rsub__ = _make_arithmetic_op(ops.rsub, cls)
cls.__rpow__ = _make_arithmetic_op(ops.rpow, cls)
cls.__pow__ = _make_arithmetic_op(operator.pow, cls)
cls.__truediv__ = _make_arithmetic_op(operator.truediv, cls)
cls.__rtruediv__ = _make_arithmetic_op(ops.rtruediv, cls)
# TODO: rmod? rdivmod?
cls.__mod__ = _make_arithmetic_op(operator.mod, cls)
cls.__floordiv__ = _make_arithmetic_op(operator.floordiv, cls)
cls.__rfloordiv__ = _make_arithmetic_op(ops.rfloordiv, cls)
cls.__divmod__ = _make_arithmetic_op(divmod, cls)
cls.__mul__ = _make_arithmetic_op(operator.mul, cls)
cls.__rmul__ = _make_arithmetic_op(ops.rmul, cls)
@classmethod
def _add_numeric_methods_unary(cls):
"""
Add in numeric unary methods.
"""
def _make_evaluate_unary(op, opstr):
def _evaluate_numeric_unary(self):
attrs = self._get_attributes_dict()
return Index(op(self.values), **attrs)
_evaluate_numeric_unary.__name__ = opstr
return _evaluate_numeric_unary
cls.__neg__ = _make_evaluate_unary(operator.neg, "__neg__")
cls.__pos__ = _make_evaluate_unary(operator.pos, "__pos__")
cls.__abs__ = _make_evaluate_unary(np.abs, "__abs__")
cls.__inv__ = _make_evaluate_unary(lambda x: -x, "__inv__")
@classmethod
def _add_numeric_methods(cls):
cls._add_numeric_methods_unary()
cls._add_numeric_methods_binary()
@classmethod
def _add_logical_methods(cls):
"""
Add in logical methods.
"""
_doc = """
%(desc)s
Parameters
----------
*args
These parameters will be passed to numpy.%(outname)s.
**kwargs
These parameters will be passed to numpy.%(outname)s.
Returns
-------
%(outname)s : bool or array_like (if axis is specified)
A single element array_like may be converted to bool."""
_index_shared_docs["index_all"] = dedent(
"""
See Also
--------
Index.any : Return whether any element in an Index is True.
Series.any : Return whether any element in a Series is True.
Series.all : Return whether all elements in a Series are True.
Notes
-----
Not a Number (NaN), positive infinity and negative infinity
evaluate to True because these are not equal to zero.
Examples
--------
**all**
True, because nonzero integers are considered True.
>>> pd.Index([1, 2, 3]).all()
True
False, because ``0`` is considered False.
>>> pd.Index([0, 1, 2]).all()
False
**any**
True, because ``1`` is considered True.
>>> pd.Index([0, 0, 1]).any()
True
False, because ``0`` is considered False.
>>> pd.Index([0, 0, 0]).any()
False
"""
)
_index_shared_docs["index_any"] = dedent(
"""
See Also
--------
Index.all : Return whether all elements are True.
Series.all : Return whether all elements are True.
Notes
-----
Not a Number (NaN), positive infinity and negative infinity
evaluate to True because these are not equal to zero.
Examples
--------
>>> index = pd.Index([0, 1, 2])
>>> index.any()
True
>>> index = pd.Index([0, 0, 0])
>>> index.any()
False
"""
)
def _make_logical_function(name, desc, f):
@Substitution(outname=name, desc=desc)
@Appender(_index_shared_docs["index_" + name])
@Appender(_doc)
def logical_func(self, *args, **kwargs):
result = f(self.values)
if (
isinstance(result, (np.ndarray, ABCSeries, Index))
and result.ndim == 0
):
# return NumPy type
return result.dtype.type(result.item())
else: # pragma: no cover
return result
logical_func.__name__ = name
return logical_func
cls.all = _make_logical_function(
"all", "Return whether all elements are True.", np.all
)
cls.any = _make_logical_function(
"any", "Return whether any element is True.", np.any
)
@classmethod
def _add_logical_methods_disabled(cls):
"""
Add in logical methods to disable.
"""
cls.all = make_invalid_op("all")
cls.any = make_invalid_op("any")
@property
def shape(self):
"""
Return a tuple of the shape of the underlying data.
"""
# not using "(len(self), )" to return "correct" shape if the values
# consists of a >1 D array (see GH-27775)
# overridden in MultiIndex.shape to avoid materializing the values
return self._values.shape
Index._add_numeric_methods_disabled()
Index._add_logical_methods()
Index._add_comparison_methods()
def ensure_index_from_sequences(sequences, names=None):
"""
Construct an index from sequences of data.
A single sequence returns an Index. Many sequences returns a
MultiIndex.
Parameters
----------
sequences : sequence of sequences
names : sequence of str
Returns
-------
index : Index or MultiIndex
Examples
--------
>>> ensure_index_from_sequences([[1, 2, 3]], names=['name'])
Int64Index([1, 2, 3], dtype='int64', name='name')
>>> ensure_index_from_sequences([['a', 'a'], ['a', 'b']],
names=['L1', 'L2'])
MultiIndex([('a', 'a'),
('a', 'b')],
names=['L1', 'L2'])
See Also
--------
ensure_index
"""
from pandas.core.indexes.multi import MultiIndex
if len(sequences) == 1:
if names is not None:
names = names[0]
return Index(sequences[0], name=names)
else:
return MultiIndex.from_arrays(sequences, names=names)
def ensure_index(index_like, copy=False):
"""
Ensure that we have an index from some index-like object.
Parameters
----------
index : sequence
An Index or other sequence
copy : bool
Returns
-------
index : Index or MultiIndex
Examples
--------
>>> ensure_index(['a', 'b'])
Index(['a', 'b'], dtype='object')
>>> ensure_index([('a', 'a'), ('b', 'c')])
Index([('a', 'a'), ('b', 'c')], dtype='object')
>>> ensure_index([['a', 'a'], ['b', 'c']])
MultiIndex([('a', 'b'),
('a', 'c')],
dtype='object')
)
See Also
--------
ensure_index_from_sequences
"""
if isinstance(index_like, Index):
if copy:
index_like = index_like.copy()
return index_like
if hasattr(index_like, "name"):
return Index(index_like, name=index_like.name, copy=copy)
if is_iterator(index_like):
index_like = list(index_like)
# must check for exactly list here because of strict type
# check in clean_index_list
if isinstance(index_like, list):
if type(index_like) != list:
index_like = list(index_like)
converted, all_arrays = lib.clean_index_list(index_like)
if len(converted) > 0 and all_arrays:
from pandas.core.indexes.multi import MultiIndex
return MultiIndex.from_arrays(converted)
else:
index_like = converted
else:
# clean_index_list does the equivalent of copying
# so only need to do this if not list instance
if copy:
from copy import copy
index_like = copy(index_like)
return Index(index_like)
def _ensure_has_len(seq):
"""
If seq is an iterator, put its values into a list.
"""
try:
len(seq)
except TypeError:
return list(seq)
else:
return seq
def _trim_front(strings):
"""
Trims zeros and decimal points.
"""
trimmed = strings
while len(strings) > 0 and all(x[0] == " " for x in trimmed):
trimmed = [x[1:] for x in trimmed]
return trimmed
def _validate_join_method(method):
if method not in ["left", "right", "inner", "outer"]:
raise ValueError(f"do not recognize join method {method}")
def default_index(n):
from pandas.core.indexes.range import RangeIndex
return RangeIndex(0, n, name=None)
def maybe_extract_name(name, obj, cls) -> Optional[Hashable]:
"""
If no name is passed, then extract it from data, validating hashability.
"""
if name is None and isinstance(obj, (Index, ABCSeries)):
# Note we don't just check for "name" attribute since that would
# pick up e.g. dtype.name
name = obj.name
# GH#29069
if not is_hashable(name):
raise TypeError(f"{cls.__name__}.name must be a hashable type")
return name
def _maybe_cast_with_dtype(data: np.ndarray, dtype: np.dtype, copy: bool) -> np.ndarray:
"""
If a dtype is passed, cast to the closest matching dtype that is supported
by Index.
Parameters
----------
data : np.ndarray
dtype : np.dtype
copy : bool
Returns
-------
np.ndarray
"""
# we need to avoid having numpy coerce
# things that look like ints/floats to ints unless
# they are actually ints, e.g. '0' and 0.0
# should not be coerced
# GH 11836
if is_integer_dtype(dtype):
inferred = lib.infer_dtype(data, skipna=False)
if inferred == "integer":
data = maybe_cast_to_integer_array(data, dtype, copy=copy)
elif inferred in ["floating", "mixed-integer-float"]:
if isna(data).any():
raise ValueError("cannot convert float NaN to integer")
if inferred == "mixed-integer-float":
data = maybe_cast_to_integer_array(data, dtype)
# If we are actually all equal to integers,
# then coerce to integer.
try:
data = _try_convert_to_int_array(data, copy, dtype)
except ValueError:
data = np.array(data, dtype=np.float64, copy=copy)
elif inferred == "string":
pass
else:
data = data.astype(dtype)
elif is_float_dtype(dtype):
inferred = lib.infer_dtype(data, skipna=False)
if inferred == "string":
pass
else:
data = data.astype(dtype)
else:
data = np.array(data, dtype=dtype, copy=copy)
return data
def _maybe_cast_data_without_dtype(subarr):
"""
If we have an arraylike input but no passed dtype, try to infer
a supported dtype.
Parameters
----------
subarr : np.ndarray, Index, or Series
Returns
-------
converted : np.ndarray or ExtensionArray
dtype : np.dtype or ExtensionDtype
"""
# Runtime import needed bc IntervalArray imports Index
from pandas.core.arrays import (
IntervalArray,
PeriodArray,
DatetimeArray,
TimedeltaArray,
)
inferred = lib.infer_dtype(subarr, skipna=False)
if inferred == "integer":
try:
data = _try_convert_to_int_array(subarr, False, None)
return data, data.dtype
except ValueError:
pass
return subarr, object
elif inferred in ["floating", "mixed-integer-float", "integer-na"]:
# TODO: Returns IntegerArray for integer-na case in the future
return subarr, np.float64
elif inferred == "interval":
try:
data = IntervalArray._from_sequence(subarr, copy=False)
return data, data.dtype
except ValueError:
# GH27172: mixed closed Intervals --> object dtype
pass
elif inferred == "boolean":
# don't support boolean explicitly ATM
pass
elif inferred != "string":
if inferred.startswith("datetime"):
try:
data = DatetimeArray._from_sequence(subarr, copy=False)
return data, data.dtype
except (ValueError, OutOfBoundsDatetime):
# GH 27011
# If we have mixed timezones, just send it
# down the base constructor
pass
elif inferred.startswith("timedelta"):
data = TimedeltaArray._from_sequence(subarr, copy=False)
return data, data.dtype
elif inferred == "period":
try:
data = PeriodArray._from_sequence(subarr)
return data, data.dtype
except IncompatibleFrequency:
pass
return subarr, subarr.dtype
def _try_convert_to_int_array(
data: np.ndarray, copy: bool, dtype: np.dtype
) -> np.ndarray:
"""
Attempt to convert an array of data into an integer array.
Parameters
----------
data : The data to convert.
copy : bool
Whether to copy the data or not.
dtype : np.dtype
Returns
-------
int_array : data converted to either an ndarray[int64] or ndarray[uint64]
Raises
------
ValueError if the conversion was not successful.
"""
if not is_unsigned_integer_dtype(dtype):
# skip int64 conversion attempt if uint-like dtype is passed, as
# this could return Int64Index when UInt64Index is what's desired
try:
res = data.astype("i8", copy=False)
if (res == data).all():
return res # TODO: might still need to copy
except (OverflowError, TypeError, ValueError):
pass
# Conversion to int64 failed (possibly due to overflow) or was skipped,
# so let's try now with uint64.
try:
res = data.astype("u8", copy=False)
if (res == data).all():
return res # TODO: might still need to copy
except (OverflowError, TypeError, ValueError):
pass
raise ValueError
def _maybe_asobject(dtype, klass, data, copy: bool, name: Label, **kwargs):
"""
If an object dtype was specified, create the non-object Index
and then convert it to object.
Parameters
----------
dtype : np.dtype, ExtensionDtype, str
klass : Index subclass
data : list-like
copy : bool
name : hashable
**kwargs
Returns
-------
Index
Notes
-----
We assume that calling .astype(object) on this klass will make a copy.
"""
# GH#23524 passing `dtype=object` to DatetimeIndex is invalid,
# will raise in the where `data` is already tz-aware. So
# we leave it out of this step and cast to object-dtype after
# the DatetimeIndex construction.
if is_dtype_equal(_o_dtype, dtype):
# Note we can pass copy=False because the .astype below
# will always make a copy
index = klass(data, copy=False, name=name, **kwargs)
return index.astype(object)
return klass(data, dtype=dtype, copy=copy, name=name, **kwargs)
from datetime import datetime
import operator
from textwrap import dedent
from typing import TYPE_CHECKING, Any, FrozenSet, Hashable, Optional, Union
import warnings
import numpy as np
from pandas._libs import algos as libalgos, index as libindex, lib
import pandas._libs.join as libjoin
from pandas._libs.lib import is_datetime_array
from pandas._libs.tslibs import OutOfBoundsDatetime, Timestamp
from pandas._libs.tslibs.period import IncompatibleFrequency
from pandas._libs.tslibs.timezones import tz_compare
from pandas._typing import Label
from pandas.compat import set_function_name
from pandas.compat.numpy import function as nv
from pandas.util._decorators import Appender, Substitution, cache_readonly
from pandas.core.dtypes import concat as _concat
from pandas.core.dtypes.cast import (
maybe_cast_to_integer_array,
validate_numeric_casting,
)
from pandas.core.dtypes.common import (
ensure_categorical,
ensure_int64,
ensure_object,
ensure_platform_int,
is_bool,
is_bool_dtype,
is_categorical,
is_categorical_dtype,
is_datetime64_any_dtype,
is_datetime64tz_dtype,
is_dtype_equal,
is_extension_array_dtype,
is_float,
is_float_dtype,
is_hashable,
is_integer,
is_integer_dtype,
is_interval_dtype,
is_iterator,
is_list_like,
is_object_dtype,
is_period_dtype,
is_scalar,
is_signed_integer_dtype,
is_timedelta64_dtype,
is_unsigned_integer_dtype,
)
from pandas.core.dtypes.concat import concat_compat
from pandas.core.dtypes.generic import (
ABCCategorical,
ABCDataFrame,
ABCDatetimeIndex,
ABCIntervalIndex,
ABCMultiIndex,
ABCPandasArray,
ABCPeriodIndex,
ABCRangeIndex,
ABCSeries,
ABCTimedeltaIndex,
)
from pandas.core.dtypes.missing import array_equivalent, isna
from pandas.core import ops
from pandas.core.accessor import CachedAccessor
import pandas.core.algorithms as algos
from pandas.core.arrays import ExtensionArray
from pandas.core.base import IndexOpsMixin, PandasObject
import pandas.core.common as com
from pandas.core.indexers import deprecate_ndim_indexing
from pandas.core.indexes.frozen import FrozenList
import pandas.core.missing as missing
from pandas.core.ops import get_op_result_name
from pandas.core.ops.invalid import make_invalid_op
from pandas.core.strings import StringMethods
from pandas.io.formats.printing import (
PrettyDict,
default_pprint,
format_object_attrs,
format_object_summary,
pprint_thing,
)
if TYPE_CHECKING:
from pandas import Series
__all__ = ["Index"]
_unsortable_types = frozenset(("mixed", "mixed-integer"))
_index_doc_kwargs = dict(
klass="Index",
inplace="",
target_klass="Index",
raises_section="",
unique="Index",
duplicated="np.ndarray",
)
_index_shared_docs = dict()
str_t = str
def _make_comparison_op(op, cls):
def cmp_method(self, other):
if isinstance(other, (np.ndarray, Index, ABCSeries, ExtensionArray)):
if other.ndim > 0 and len(self) != len(other):
raise ValueError("Lengths must match to compare")
if is_object_dtype(self) and isinstance(other, ABCCategorical):
left = type(other)(self._values, dtype=other.dtype)
return op(left, other)
elif is_object_dtype(self) and isinstance(other, ExtensionArray):
# e.g. PeriodArray
with np.errstate(all="ignore"):
result = op(self.values, other)
elif is_object_dtype(self) and not isinstance(self, ABCMultiIndex):
# don't pass MultiIndex
with np.errstate(all="ignore"):
result = ops.comp_method_OBJECT_ARRAY(op, self.values, other)
else:
with np.errstate(all="ignore"):
result = op(self.values, np.asarray(other))
if is_bool_dtype(result):
return result
return ops.invalid_comparison(self, other, op)
name = f"__{op.__name__}__"
return set_function_name(cmp_method, name, cls)
def _make_arithmetic_op(op, cls):
def index_arithmetic_method(self, other):
if isinstance(other, (ABCSeries, ABCDataFrame, ABCTimedeltaIndex)):
return NotImplemented
from pandas import Series
result = op(Series(self), other)
if isinstance(result, tuple):
return (Index(result[0]), Index(result[1]))
return Index(result)
name = f"__{op.__name__}__"
# TODO: docstring?
return set_function_name(index_arithmetic_method, name, cls)
class InvalidIndexError(Exception):
pass
_o_dtype = np.dtype(object)
_Identity = object
def _new_Index(cls, d):
"""
This is called upon unpickling, rather than the default which doesn't
have arguments and breaks __new__.
"""
# required for backward compat, because PI can't be instantiated with
# ordinals through __new__ GH #13277
if issubclass(cls, ABCPeriodIndex):
from pandas.core.indexes.period import _new_PeriodIndex
return _new_PeriodIndex(cls, **d)
if issubclass(cls, ABCMultiIndex):
if "labels" in d and "codes" not in d:
# GH#23752 "labels" kwarg has been replaced with "codes"
d["codes"] = d.pop("labels")
return cls.__new__(cls, **d)
class Index(IndexOpsMixin, PandasObject):
"""
Immutable ndarray implementing an ordered, sliceable set. The basic object
storing axis labels for all pandas objects.
Parameters
----------
data : array-like (1-dimensional)
dtype : NumPy dtype (default: object)
If dtype is None, we find the dtype that best fits the data.
If an actual dtype is provided, we coerce to that dtype if it's safe.
Otherwise, an error will be raised.
copy : bool
Make a copy of input ndarray.
name : object
Name to be stored in the index.
tupleize_cols : bool (default: True)
When True, attempt to create a MultiIndex if possible.
See Also
--------
RangeIndex : Index implementing a monotonic integer range.
CategoricalIndex : Index of :class:`Categorical` s.
MultiIndex : A multi-level, or hierarchical, Index.
IntervalIndex : An Index of :class:`Interval` s.
DatetimeIndex, TimedeltaIndex, PeriodIndex
Int64Index, UInt64Index, Float64Index
Notes
-----
An Index instance can **only** contain hashable objects
Examples
--------
>>> pd.Index([1, 2, 3])
Int64Index([1, 2, 3], dtype='int64')
>>> pd.Index(list('abc'))
Index(['a', 'b', 'c'], dtype='object')
"""
# tolist is not actually deprecated, just suppressed in the __dir__
_deprecations: FrozenSet[str] = (
PandasObject._deprecations
| IndexOpsMixin._deprecations
| frozenset(["contains", "set_value"])
)
# To hand over control to subclasses
_join_precedence = 1
# Cython methods; see github.com/cython/cython/issues/2647
# for why we need to wrap these instead of making them class attributes
# Moreover, cython will choose the appropriate-dtyped sub-function
# given the dtypes of the passed arguments
def _left_indexer_unique(self, left, right):
return libjoin.left_join_indexer_unique(left, right)
def _left_indexer(self, left, right):
return libjoin.left_join_indexer(left, right)
def _inner_indexer(self, left, right):
return libjoin.inner_join_indexer(left, right)
def _outer_indexer(self, left, right):
return libjoin.outer_join_indexer(left, right)
_typ = "index"
_data: Union[ExtensionArray, np.ndarray]
_id = None
_name: Label = None
# MultiIndex.levels previously allowed setting the index name. We
# don't allow this anymore, and raise if it happens rather than
# failing silently.
_no_setting_name: bool = False
_comparables = ["name"]
_attributes = ["name"]
_is_numeric_dtype = False
_can_hold_na = True
# would we like our indexing holder to defer to us
_defer_to_indexing = False
# prioritize current class for _shallow_copy_with_infer,
# used to infer integers as datetime-likes
_infer_as_myclass = False
_engine_type = libindex.ObjectEngine
# whether we support partial string indexing. Overridden
# in DatetimeIndex and PeriodIndex
_supports_partial_string_indexing = False
_accessors = {"str"}
str = CachedAccessor("str", StringMethods)
# --------------------------------------------------------------------
# Constructors
def __new__(
cls, data=None, dtype=None, copy=False, name=None, tupleize_cols=True, **kwargs,
) -> "Index":
from pandas.core.indexes.range import RangeIndex
name = maybe_extract_name(name, data, cls)
if isinstance(data, ABCPandasArray):
# ensure users don't accidentally put a PandasArray in an index.
data = data.to_numpy()
# range
if isinstance(data, RangeIndex):
return RangeIndex(start=data, copy=copy, dtype=dtype, name=name)
elif isinstance(data, range):
return RangeIndex.from_range(data, dtype=dtype, name=name)
# categorical
elif is_categorical_dtype(data) or is_categorical_dtype(dtype):
# Delay import for perf. https://github.com/pandas-dev/pandas/pull/31423
from pandas.core.indexes.category import CategoricalIndex
return CategoricalIndex(data, dtype=dtype, copy=copy, name=name, **kwargs)
# interval
elif is_interval_dtype(data) or is_interval_dtype(dtype):
# Delay import for perf. https://github.com/pandas-dev/pandas/pull/31423
from pandas.core.indexes.interval import IntervalIndex
return _maybe_asobject(dtype, IntervalIndex, data, copy, name, **kwargs)
elif (
is_datetime64_any_dtype(data)
or is_datetime64_any_dtype(dtype)
or "tz" in kwargs
):
# Delay import for perf. https://github.com/pandas-dev/pandas/pull/31423
from pandas import DatetimeIndex
return _maybe_asobject(dtype, DatetimeIndex, data, copy, name, **kwargs)
elif is_timedelta64_dtype(data) or is_timedelta64_dtype(dtype):
# Delay import for perf. https://github.com/pandas-dev/pandas/pull/31423
from pandas import TimedeltaIndex
return _maybe_asobject(dtype, TimedeltaIndex, data, copy, name, **kwargs)
elif is_period_dtype(data) or is_period_dtype(dtype):
# Delay import for perf. https://github.com/pandas-dev/pandas/pull/31423
from pandas import PeriodIndex
return _maybe_asobject(dtype, PeriodIndex, data, copy, name, **kwargs)
# extension dtype
elif is_extension_array_dtype(data) or is_extension_array_dtype(dtype):
if not (dtype is None or is_object_dtype(dtype)):
# coerce to the provided dtype
ea_cls = dtype.construct_array_type()
data = ea_cls._from_sequence(data, dtype=dtype, copy=False)
else:
data = np.asarray(data, dtype=object)
# coerce to the object dtype
data = data.astype(object)
return Index(data, dtype=object, copy=copy, name=name, **kwargs)
# index-like
elif isinstance(data, (np.ndarray, Index, ABCSeries)):
# Delay import for perf. https://github.com/pandas-dev/pandas/pull/31423
from pandas.core.indexes.numeric import (
Float64Index,
Int64Index,
UInt64Index,
)
if dtype is not None:
# we need to avoid having numpy coerce
# things that look like ints/floats to ints unless
# they are actually ints, e.g. '0' and 0.0
# should not be coerced
# GH 11836
data = _maybe_cast_with_dtype(data, dtype, copy)
dtype = data.dtype # TODO: maybe not for object?
# maybe coerce to a sub-class
if is_signed_integer_dtype(data.dtype):
return Int64Index(data, copy=copy, dtype=dtype, name=name)
elif is_unsigned_integer_dtype(data.dtype):
return UInt64Index(data, copy=copy, dtype=dtype, name=name)
elif is_float_dtype(data.dtype):
return Float64Index(data, copy=copy, dtype=dtype, name=name)
elif issubclass(data.dtype.type, np.bool) or is_bool_dtype(data):
subarr = data.astype("object")
else:
subarr = com.asarray_tuplesafe(data, dtype=object)
# asarray_tuplesafe does not always copy underlying data,
# so need to make sure that this happens
if copy:
subarr = subarr.copy()
if dtype is None:
new_data, new_dtype = _maybe_cast_data_without_dtype(subarr)
if new_dtype is not None:
return cls(
new_data, dtype=new_dtype, copy=False, name=name, **kwargs
)
if kwargs:
raise TypeError(f"Unexpected keyword arguments {repr(set(kwargs))}")
if subarr.ndim > 1:
# GH#13601, GH#20285, GH#27125
raise ValueError("Index data must be 1-dimensional")
return cls._simple_new(subarr, name)
elif hasattr(data, "__array__"):
return Index(np.asarray(data), dtype=dtype, copy=copy, name=name, **kwargs)
elif data is None or is_scalar(data):
raise cls._scalar_data_error(data)
else:
if tupleize_cols and is_list_like(data):
# GH21470: convert iterable to list before determining if empty
if is_iterator(data):
data = list(data)
if data and all(isinstance(e, tuple) for e in data):
# we must be all tuples, otherwise don't construct
# 10697
from pandas.core.indexes.multi import MultiIndex
return MultiIndex.from_tuples(
data, names=name or kwargs.get("names")
)
# other iterable of some kind
subarr = com.asarray_tuplesafe(data, dtype=object)
return Index(subarr, dtype=dtype, copy=copy, name=name, **kwargs)
"""
NOTE for new Index creation:
- _simple_new: It returns new Index with the same type as the caller.
All metadata (such as name) must be provided by caller's responsibility.
Using _shallow_copy is recommended because it fills these metadata
otherwise specified.
- _shallow_copy: It returns new Index with the same type (using
_simple_new), but fills caller's metadata otherwise specified. Passed
kwargs will overwrite corresponding metadata.
- _shallow_copy_with_infer: It returns new Index inferring its type
from passed values. It fills caller's metadata otherwise specified as the
same as _shallow_copy.
See each method's docstring.
"""
@property
def asi8(self):
"""
Integer representation of the values.
Returns
-------
ndarray
An ndarray with int64 dtype.
"""
return None
@classmethod
def _simple_new(cls, values, name=None, dtype=None):
"""
We require that we have a dtype compat for the values. If we are passed
a non-dtype compat, then coerce using the constructor.
Must be careful not to recurse.
"""
assert isinstance(values, np.ndarray), type(values)
result = object.__new__(cls)
result._data = values
# _index_data is a (temporary?) fix to ensure that the direct data
# manipulation we do in `_libs/reduction.pyx` continues to work.
# We need access to the actual ndarray, since we're messing with
# data buffers and strides. We don't re-use `_ndarray_values`, since
# we actually set this value too.
result._index_data = values
result._name = name
return result._reset_identity()
@cache_readonly
def _constructor(self):
return type(self)
# --------------------------------------------------------------------
# Index Internals Methods
def _get_attributes_dict(self):
"""
Return an attributes dict for my class.
"""
return {k: getattr(self, k, None) for k in self._attributes}
def _shallow_copy(self, values=None, **kwargs):
"""
Create a new Index with the same class as the caller, don't copy the
data, use the same object attributes with passed in attributes taking
precedence.
*this is an internal non-public method*
Parameters
----------
values : the values to create the new Index, optional
kwargs : updates the default attributes for this Index
"""
if values is None:
values = self.values
attributes = self._get_attributes_dict()
attributes.update(kwargs)
return self._simple_new(values, **attributes)
def _shallow_copy_with_infer(self, values, **kwargs):
"""
Create a new Index inferring the class with passed value, don't copy
the data, use the same object attributes with passed in attributes
taking precedence.
*this is an internal non-public method*
Parameters
----------
values : the values to create the new Index, optional
kwargs : updates the default attributes for this Index
"""
attributes = self._get_attributes_dict()
attributes.update(kwargs)
attributes["copy"] = False
if not len(values) and "dtype" not in kwargs:
# TODO: what if hasattr(values, "dtype")?
attributes["dtype"] = self.dtype
if self._infer_as_myclass:
try:
return self._constructor(values, **attributes)
except (TypeError, ValueError):
pass
return Index(values, **attributes)
def _update_inplace(self, result, **kwargs):
# guard when called from IndexOpsMixin
raise TypeError("Index can't be updated inplace")
def is_(self, other) -> bool:
"""
More flexible, faster check like ``is`` but that works through views.
Note: this is *not* the same as ``Index.identical()``, which checks
that metadata is also the same.
Parameters
----------
other : object
other object to compare against.
Returns
-------
True if both have same underlying data, False otherwise : bool
"""
# use something other than None to be clearer
return self._id is getattr(other, "_id", Ellipsis) and self._id is not None
def _reset_identity(self):
"""
Initializes or resets ``_id`` attribute with new object.
"""
self._id = _Identity()
return self
def _cleanup(self):
self._engine.clear_mapping()
@cache_readonly
def _engine(self):
# property, for now, slow to look up
# to avoid a reference cycle, bind `_ndarray_values` to a local variable, so
# `self` is not passed into the lambda.
_ndarray_values = self._ndarray_values
return self._engine_type(lambda: _ndarray_values, len(self))
# --------------------------------------------------------------------
# Array-Like Methods
# ndarray compat
def __len__(self) -> int:
"""
Return the length of the Index.
"""
return len(self._data)
def __array__(self, dtype=None) -> np.ndarray:
"""
The array interface, return my values.
"""
return np.asarray(self._data, dtype=dtype)
def __array_wrap__(self, result, context=None):
"""
Gets called after a ufunc.
"""
result = lib.item_from_zerodim(result)
if is_bool_dtype(result) or lib.is_scalar(result) or np.ndim(result) > 1:
return result
attrs = self._get_attributes_dict()
return Index(result, **attrs)
@cache_readonly
def dtype(self):
"""
Return the dtype object of the underlying data.
"""
return self._data.dtype
def ravel(self, order="C"):
"""
Return an ndarray of the flattened values of the underlying data.
Returns
-------
numpy.ndarray
Flattened array.
See Also
--------
numpy.ndarray.ravel
"""
return self._ndarray_values.ravel(order=order)
def view(self, cls=None):
# we need to see if we are subclassing an
# index type here
if cls is not None and not hasattr(cls, "_typ"):
result = self._data.view(cls)
else:
result = self._shallow_copy()
if isinstance(result, Index):
result._id = self._id
return result
def astype(self, dtype, copy=True):
"""
Create an Index with values cast to dtypes. The class of a new Index
is determined by dtype. When conversion is impossible, a ValueError
exception is raised.
Parameters
----------
dtype : numpy dtype or pandas type
Note that any signed integer `dtype` is treated as ``'int64'``,
and any unsigned integer `dtype` is treated as ``'uint64'``,
regardless of the size.
copy : bool, default True
By default, astype always returns a newly allocated object.
If copy is set to False and internal requirements on dtype are
satisfied, the original data is used to create a new Index
or the original Index is returned.
Returns
-------
Index
Index with values cast to specified dtype.
"""
if is_dtype_equal(self.dtype, dtype):
return self.copy() if copy else self
elif is_categorical_dtype(dtype):
from pandas.core.indexes.category import CategoricalIndex
return CategoricalIndex(self.values, name=self.name, dtype=dtype, copy=copy)
elif is_extension_array_dtype(dtype):
return Index(np.asarray(self), dtype=dtype, copy=copy)
try:
casted = self.values.astype(dtype, copy=copy)
except (TypeError, ValueError):
raise TypeError(f"Cannot cast {type(self).__name__} to dtype {dtype}")
return Index(casted, name=self.name, dtype=dtype)
_index_shared_docs[
"take"
] = """
Return a new %(klass)s of the values selected by the indices.
For internal compatibility with numpy arrays.
Parameters
----------
indices : list
Indices to be taken.
axis : int, optional
The axis over which to select values, always 0.
allow_fill : bool, default True
fill_value : bool, default None
If allow_fill=True and fill_value is not None, indices specified by
-1 is regarded as NA. If Index doesn't hold NA, raise ValueError.
Returns
-------
numpy.ndarray
Elements of given indices.
See Also
--------
numpy.ndarray.take
"""
@Appender(_index_shared_docs["take"] % _index_doc_kwargs)
def take(self, indices, axis=0, allow_fill=True, fill_value=None, **kwargs):
if kwargs:
nv.validate_take(tuple(), kwargs)
indices = ensure_platform_int(indices)
if self._can_hold_na:
taken = self._assert_take_fillable(
self.values,
indices,
allow_fill=allow_fill,
fill_value=fill_value,
na_value=self._na_value,
)
else:
if allow_fill and fill_value is not None:
cls_name = type(self).__name__
raise ValueError(
f"Unable to fill values because {cls_name} cannot contain NA"
)
taken = self.values.take(indices)
return self._shallow_copy(taken)
def _assert_take_fillable(
self, values, indices, allow_fill=True, fill_value=None, na_value=np.nan
):
"""
Internal method to handle NA filling of take.
"""
indices = ensure_platform_int(indices)
# only fill if we are passing a non-None fill_value
if allow_fill and fill_value is not None:
if (indices < -1).any():
raise ValueError(
"When allow_fill=True and fill_value is not None, "
"all indices must be >= -1"
)
taken = algos.take(
values, indices, allow_fill=allow_fill, fill_value=na_value
)
else:
taken = values.take(indices)
return taken
_index_shared_docs[
"repeat"
] = """
Repeat elements of a %(klass)s.
Returns a new %(klass)s where each element of the current %(klass)s
is repeated consecutively a given number of times.
Parameters
----------
repeats : int or array of ints
The number of repetitions for each element. This should be a
non-negative integer. Repeating 0 times will return an empty
%(klass)s.
axis : None
Must be ``None``. Has no effect but is accepted for compatibility
with numpy.
Returns
-------
repeated_index : %(klass)s
Newly created %(klass)s with repeated elements.
See Also
--------
Series.repeat : Equivalent function for Series.
numpy.repeat : Similar method for :class:`numpy.ndarray`.
Examples
--------
>>> idx = pd.Index(['a', 'b', 'c'])
>>> idx
Index(['a', 'b', 'c'], dtype='object')
>>> idx.repeat(2)
Index(['a', 'a', 'b', 'b', 'c', 'c'], dtype='object')
>>> idx.repeat([1, 2, 3])
Index(['a', 'b', 'b', 'c', 'c', 'c'], dtype='object')
"""
@Appender(_index_shared_docs["repeat"] % _index_doc_kwargs)
def repeat(self, repeats, axis=None):
repeats = ensure_platform_int(repeats)
nv.validate_repeat(tuple(), dict(axis=axis))
return self._shallow_copy(self._values.repeat(repeats))
# --------------------------------------------------------------------
# Copying Methods
def copy(self, name=None, deep=False, dtype=None, names=None):
"""
Make a copy of this object. Name and dtype sets those attributes on
the new object.
Parameters
----------
name : Label
deep : bool, default False
dtype : numpy dtype or pandas type, optional
names : list-like, optional
Kept for compatibility with MultiIndex. Should not be used.
Returns
-------
Index
Notes
-----
In most cases, there should be no functional difference from using
``deep``, but if ``deep`` is passed it will attempt to deepcopy.
"""
if deep:
new_index = self._shallow_copy(self._data.copy())
else:
new_index = self._shallow_copy()
names = self._validate_names(name=name, names=names, deep=deep)
new_index = new_index.set_names(names)
if dtype:
new_index = new_index.astype(dtype)
return new_index
def __copy__(self, **kwargs):
return self.copy(**kwargs)
def __deepcopy__(self, memo=None):
"""
Parameters
----------
memo, default None
Standard signature. Unused
"""
return self.copy(deep=True)
# --------------------------------------------------------------------
# Rendering Methods
def __repr__(self) -> str_t:
"""
Return a string representation for this object.
"""
klass_name = type(self).__name__
data = self._format_data()
attrs = self._format_attrs()
space = self._format_space()
attrs_str = [f"{k}={v}" for k, v in attrs]
prepr = f",{space}".join(attrs_str)
# no data provided, just attributes
if data is None:
data = ""
res = f"{klass_name}({data}{prepr})"
return res
def _format_space(self) -> str_t:
# using space here controls if the attributes
# are line separated or not (the default)
# max_seq_items = get_option('display.max_seq_items')
# if len(self) > max_seq_items:
# space = "\n%s" % (' ' * (len(klass) + 1))
return " "
@property
def _formatter_func(self):
"""
Return the formatter function.
"""
return default_pprint
def _format_data(self, name=None) -> str_t:
"""
Return the formatted data as a unicode string.
"""
# do we want to justify (only do so for non-objects)
is_justify = True
if self.inferred_type == "string":
is_justify = False
elif self.inferred_type == "categorical":
if is_object_dtype(self.categories): # type: ignore
is_justify = False
return format_object_summary(
self, self._formatter_func, is_justify=is_justify, name=name
)
def _format_attrs(self):
"""
Return a list of tuples of the (attr,formatted_value).
"""
return format_object_attrs(self)
def _mpl_repr(self):
# how to represent ourselves to matplotlib
return self.values
def format(self, name: bool = False, formatter=None, **kwargs):
"""
Render a string representation of the Index.
"""
header = []
if name:
header.append(
pprint_thing(self.name, escape_chars=("\t", "\r", "\n"))
if self.name is not None
else ""
)
if formatter is not None:
return header + list(self.map(formatter))
return self._format_with_header(header, **kwargs)
def _format_with_header(self, header, na_rep="NaN", **kwargs):
values = self.values
from pandas.io.formats.format import format_array
if is_categorical_dtype(values.dtype):
values = np.array(values)
elif is_object_dtype(values.dtype):
values = lib.maybe_convert_objects(values, safe=1)
if is_object_dtype(values.dtype):
result = [pprint_thing(x, escape_chars=("\t", "\r", "\n")) for x in values]
# could have nans
mask = isna(values)
if mask.any():
result = np.array(result)
result[mask] = na_rep
result = result.tolist()
else:
result = _trim_front(format_array(values, None, justify="left"))
return header + result
def to_native_types(self, slicer=None, **kwargs):
"""
Format specified values of `self` and return them.
Parameters
----------
slicer : int, array-like
An indexer into `self` that specifies which values
are used in the formatting process.
kwargs : dict
Options for specifying how the values should be formatted.
These options include the following:
1) na_rep : str
The value that serves as a placeholder for NULL values
2) quoting : bool or None
Whether or not there are quoted values in `self`
3) date_format : str
The format used to represent date-like values.
Returns
-------
numpy.ndarray
Formatted values.
"""
values = self
if slicer is not None:
values = values[slicer]
return values._format_native_types(**kwargs)
def _format_native_types(self, na_rep="", quoting=None, **kwargs):
"""
Actually format specific types of the index.
"""
mask = isna(self)
if not self.is_object() and not quoting:
values = np.asarray(self).astype(str)
else:
values = np.array(self, dtype=object, copy=True)
values[mask] = na_rep
return values
def _summary(self, name=None) -> str_t:
"""
Return a summarized representation.
Parameters
----------
name : str
name to use in the summary representation
Returns
-------
String with a summarized representation of the index
"""
if len(self) > 0:
head = self[0]
if hasattr(head, "format") and not isinstance(head, str):
head = head.format()
tail = self[-1]
if hasattr(tail, "format") and not isinstance(tail, str):
tail = tail.format()
index_summary = f", {head} to {tail}"
else:
index_summary = ""
if name is None:
name = type(self).__name__
return f"{name}: {len(self)} entries{index_summary}"
# --------------------------------------------------------------------
# Conversion Methods
def to_flat_index(self):
"""
Identity method.
.. versionadded:: 0.24.0
This is implemented for compatibility with subclass implementations
when chaining.
Returns
-------
pd.Index
Caller.
See Also
--------
MultiIndex.to_flat_index : Subclass implementation.
"""
return self
def to_series(self, index=None, name=None):
"""
Create a Series with both index and values equal to the index keys.
Useful with map for returning an indexer based on an index.
Parameters
----------
index : Index, optional
Index of resulting Series. If None, defaults to original index.
name : str, optional
Dame of resulting Series. If None, defaults to name of original
index.
Returns
-------
Series
The dtype will be based on the type of the Index values.
"""
from pandas import Series
if index is None:
index = self._shallow_copy()
if name is None:
name = self.name
return Series(self.values.copy(), index=index, name=name)
def to_frame(self, index: bool = True, name=None):
"""
Create a DataFrame with a column containing the Index.
.. versionadded:: 0.24.0
Parameters
----------
index : bool, default True
Set the index of the returned DataFrame as the original Index.
name : object, default None
The passed name should substitute for the index name (if it has
one).
Returns
-------
DataFrame
DataFrame containing the original Index data.
See Also
--------
Index.to_series : Convert an Index to a Series.
Series.to_frame : Convert Series to DataFrame.
Examples
--------
>>> idx = pd.Index(['Ant', 'Bear', 'Cow'], name='animal')
>>> idx.to_frame()
animal
animal
Ant Ant
Bear Bear
Cow Cow
By default, the original Index is reused. To enforce a new Index:
>>> idx.to_frame(index=False)
animal
0 Ant
1 Bear
2 Cow
To override the name of the resulting column, specify `name`:
>>> idx.to_frame(index=False, name='zoo')
zoo
0 Ant
1 Bear
2 Cow
"""
from pandas import DataFrame
if name is None:
name = self.name or 0
result = DataFrame({name: self._values.copy()})
if index:
result.index = self
return result
# --------------------------------------------------------------------
# Name-Centric Methods
@property
def name(self):
"""
Return Index or MultiIndex name.
"""
return self._name
@name.setter
def name(self, value):
if self._no_setting_name:
# Used in MultiIndex.levels to avoid silently ignoring name updates.
raise RuntimeError(
"Cannot set name on a level of a MultiIndex. Use "
"'MultiIndex.set_names' instead."
)
maybe_extract_name(value, None, type(self))
self._name = value
def _validate_names(self, name=None, names=None, deep: bool = False):
"""
Handles the quirks of having a singular 'name' parameter for general
Index and plural 'names' parameter for MultiIndex.
"""
from copy import deepcopy
if names is not None and name is not None:
raise TypeError("Can only provide one of `names` and `name`")
elif names is None and name is None:
return deepcopy(self.names) if deep else self.names
elif names is not None:
if not is_list_like(names):
raise TypeError("Must pass list-like as `names`.")
return names
else:
if not is_list_like(name):
return [name]
return name
def _get_names(self):
return FrozenList((self.name,))
def _set_names(self, values, level=None):
"""
Set new names on index. Each name has to be a hashable type.
Parameters
----------
values : str or sequence
name(s) to set
level : int, level name, or sequence of int/level names (default None)
If the index is a MultiIndex (hierarchical), level(s) to set (None
for all levels). Otherwise level must be None
Raises
------
TypeError if each name is not hashable.
"""
if not is_list_like(values):
raise ValueError("Names must be a list-like")
if len(values) != 1:
raise ValueError(f"Length of new names must be 1, got {len(values)}")
# GH 20527
# All items in 'name' need to be hashable:
for name in values:
if not is_hashable(name):
raise TypeError(f"{type(self).__name__}.name must be a hashable type")
self._name = values[0]
names = property(fset=_set_names, fget=_get_names)
def set_names(self, names, level=None, inplace: bool = False):
"""
Set Index or MultiIndex name.
Able to set new names partially and by level.
Parameters
----------
names : label or list of label
Name(s) to set.
level : int, label or list of int or label, optional
If the index is a MultiIndex, level(s) to set (None for all
levels). Otherwise level must be None.
inplace : bool, default False
Modifies the object directly, instead of creating a new Index or
MultiIndex.
Returns
-------
Index
The same type as the caller or None if inplace is True.
See Also
--------
Index.rename : Able to set new names without level.
Examples
--------
>>> idx = pd.Index([1, 2, 3, 4])
>>> idx
Int64Index([1, 2, 3, 4], dtype='int64')
>>> idx.set_names('quarter')
Int64Index([1, 2, 3, 4], dtype='int64', name='quarter')
>>> idx = pd.MultiIndex.from_product([['python', 'cobra'],
... [2018, 2019]])
>>> idx
MultiIndex([('python', 2018),
('python', 2019),
( 'cobra', 2018),
( 'cobra', 2019)],
)
>>> idx.set_names(['kind', 'year'], inplace=True)
>>> idx
MultiIndex([('python', 2018),
('python', 2019),
( 'cobra', 2018),
( 'cobra', 2019)],
names=['kind', 'year'])
>>> idx.set_names('species', level=0)
MultiIndex([('python', 2018),
('python', 2019),
( 'cobra', 2018),
( 'cobra', 2019)],
names=['species', 'year'])
"""
if level is not None and not isinstance(self, ABCMultiIndex):
raise ValueError("Level must be None for non-MultiIndex")
if level is not None and not is_list_like(level) and is_list_like(names):
raise TypeError("Names must be a string when a single level is provided.")
if not is_list_like(names) and level is None and self.nlevels > 1:
raise TypeError("Must pass list-like as `names`.")
if not is_list_like(names):
names = [names]
if level is not None and not is_list_like(level):
level = [level]
if inplace:
idx = self
else:
idx = self._shallow_copy()
idx._set_names(names, level=level)
if not inplace:
return idx
def rename(self, name, inplace=False):
"""
Alter Index or MultiIndex name.
Able to set new names without level. Defaults to returning new index.
Length of names must match number of levels in MultiIndex.
Parameters
----------
name : label or list of labels
Name(s) to set.
inplace : bool, default False
Modifies the object directly, instead of creating a new Index or
MultiIndex.
Returns
-------
Index
The same type as the caller or None if inplace is True.
See Also
--------
Index.set_names : Able to set new names partially and by level.
Examples
--------
>>> idx = pd.Index(['A', 'C', 'A', 'B'], name='score')
>>> idx.rename('grade')
Index(['A', 'C', 'A', 'B'], dtype='object', name='grade')
>>> idx = pd.MultiIndex.from_product([['python', 'cobra'],
... [2018, 2019]],
... names=['kind', 'year'])
>>> idx
MultiIndex([('python', 2018),
('python', 2019),
( 'cobra', 2018),
( 'cobra', 2019)],
names=['kind', 'year'])
>>> idx.rename(['species', 'year'])
MultiIndex([('python', 2018),
('python', 2019),
( 'cobra', 2018),
( 'cobra', 2019)],
names=['species', 'year'])
>>> idx.rename('species')
Traceback (most recent call last):
TypeError: Must pass list-like as `names`.
"""
return self.set_names([name], inplace=inplace)
# --------------------------------------------------------------------
# Level-Centric Methods
@property
def nlevels(self) -> int:
"""
Number of levels.
"""
return 1
def _sort_levels_monotonic(self):
"""
Compat with MultiIndex.
"""
return self
def _validate_index_level(self, level):
"""
Validate index level.
For single-level Index getting level number is a no-op, but some
verification must be done like in MultiIndex.
"""
if isinstance(level, int):
if level < 0 and level != -1:
raise IndexError(
"Too many levels: Index has only 1 level, "
f"{level} is not a valid level number"
)
elif level > 0:
raise IndexError(
f"Too many levels: Index has only 1 level, not {level + 1}"
)
elif level != self.name:
raise KeyError(
f"Requested level ({level}) does not match index name ({self.name})"
)
def _get_level_number(self, level) -> int:
self._validate_index_level(level)
return 0
def sortlevel(self, level=None, ascending=True, sort_remaining=None):
"""
For internal compatibility with with the Index API.
Sort the Index. This is for compat with MultiIndex
Parameters
----------
ascending : bool, default True
False to sort in descending order
level, sort_remaining are compat parameters
Returns
-------
Index
"""
return self.sort_values(return_indexer=True, ascending=ascending)
def _get_level_values(self, level):
"""
Return an Index of values for requested level.
This is primarily useful to get an individual level of values from a
MultiIndex, but is provided on Index as well for compatibility.
Parameters
----------
level : int or str
It is either the integer position or the name of the level.
Returns
-------
Index
Calling object, as there is only one level in the Index.
See Also
--------
MultiIndex.get_level_values : Get values for a level of a MultiIndex.
Notes
-----
For Index, level should be 0, since there are no multiple levels.
Examples
--------
>>> idx = pd.Index(list('abc'))
>>> idx
Index(['a', 'b', 'c'], dtype='object')
Get level values by supplying `level` as integer:
>>> idx.get_level_values(0)
Index(['a', 'b', 'c'], dtype='object')
"""
self._validate_index_level(level)
return self
get_level_values = _get_level_values
def droplevel(self, level=0):
"""
Return index with requested level(s) removed.
If resulting index has only 1 level left, the result will be
of Index type, not MultiIndex.
.. versionadded:: 0.23.1 (support for non-MultiIndex)
Parameters
----------
level : int, str, or list-like, default 0
If a string is given, must be the name of a level
If list-like, elements must be names or indexes of levels.
Returns
-------
Index or MultiIndex
"""
if not isinstance(level, (tuple, list)):
level = [level]
levnums = sorted(self._get_level_number(lev) for lev in level)[::-1]
if len(level) == 0:
return self
if len(level) >= self.nlevels:
raise ValueError(
f"Cannot remove {len(level)} levels from an index with {self.nlevels} "
"levels: at least one level must be left."
)
# The two checks above guarantee that here self is a MultiIndex
new_levels = list(self.levels)
new_codes = list(self.codes)
new_names = list(self.names)
for i in levnums:
new_levels.pop(i)
new_codes.pop(i)
new_names.pop(i)
if len(new_levels) == 1:
# set nan if needed
mask = new_codes[0] == -1
result = new_levels[0].take(new_codes[0])
if mask.any():
result = result.putmask(mask, np.nan)
result._name = new_names[0]
return result
else:
from pandas.core.indexes.multi import MultiIndex
return MultiIndex(
levels=new_levels,
codes=new_codes,
names=new_names,
verify_integrity=False,
)
def _get_grouper_for_level(self, mapper, level=None):
"""
Get index grouper corresponding to an index level
Parameters
----------
mapper: Group mapping function or None
Function mapping index values to groups
level : int or None
Index level
Returns
-------
grouper : Index
Index of values to group on.
labels : ndarray of int or None
Array of locations in level_index.
uniques : Index or None
Index of unique values for level.
"""
assert level is None or level == 0
if mapper is None:
grouper = self
else:
grouper = self.map(mapper)
return grouper, None, None
# --------------------------------------------------------------------
# Introspection Methods
@property
def is_monotonic(self) -> bool:
"""
Alias for is_monotonic_increasing.
"""
return self.is_monotonic_increasing
@property
def is_monotonic_increasing(self) -> bool:
"""
Return if the index is monotonic increasing (only equal or
increasing) values.
Examples
--------
>>> Index([1, 2, 3]).is_monotonic_increasing
True
>>> Index([1, 2, 2]).is_monotonic_increasing
True
>>> Index([1, 3, 2]).is_monotonic_increasing
False
"""
return self._engine.is_monotonic_increasing
@property
def is_monotonic_decreasing(self) -> bool:
"""
Return if the index is monotonic decreasing (only equal or
decreasing) values.
Examples
--------
>>> Index([3, 2, 1]).is_monotonic_decreasing
True
>>> Index([3, 2, 2]).is_monotonic_decreasing
True
>>> Index([3, 1, 2]).is_monotonic_decreasing
False
"""
return self._engine.is_monotonic_decreasing
@property
def _is_strictly_monotonic_increasing(self) -> bool:
"""
Return if the index is strictly monotonic increasing
(only increasing) values.
Examples
--------
>>> Index([1, 2, 3])._is_strictly_monotonic_increasing
True
>>> Index([1, 2, 2])._is_strictly_monotonic_increasing
False
>>> Index([1, 3, 2])._is_strictly_monotonic_increasing
False
"""
return self.is_unique and self.is_monotonic_increasing
@property
def _is_strictly_monotonic_decreasing(self) -> bool:
"""
Return if the index is strictly monotonic decreasing
(only decreasing) values.
Examples
--------
>>> Index([3, 2, 1])._is_strictly_monotonic_decreasing
True
>>> Index([3, 2, 2])._is_strictly_monotonic_decreasing
False
>>> Index([3, 1, 2])._is_strictly_monotonic_decreasing
False
"""
return self.is_unique and self.is_monotonic_decreasing
@cache_readonly
def is_unique(self) -> bool:
"""
Return if the index has unique values.
"""
return self._engine.is_unique
@property
def has_duplicates(self) -> bool:
"""
Check if the Index has duplicate values.
Returns
-------
bool
Whether or not the Index has duplicate values.
Examples
--------
>>> idx = pd.Index([1, 5, 7, 7])
>>> idx.has_duplicates
True
>>> idx = pd.Index([1, 5, 7])
>>> idx.has_duplicates
False
>>> idx = pd.Index(["Watermelon", "Orange", "Apple",
... "Watermelon"]).astype("category")
>>> idx.has_duplicates
True
>>> idx = pd.Index(["Orange", "Apple",
... "Watermelon"]).astype("category")
>>> idx.has_duplicates
False
"""
return not self.is_unique
def is_boolean(self) -> bool:
"""
Check if the Index only consists of booleans.
Returns
-------
bool
Whether or not the Index only consists of booleans.
See Also
--------
is_integer : Check if the Index only consists of integers.
is_floating : Check if the Index is a floating type.
is_numeric : Check if the Index only consists of numeric data.
is_object : Check if the Index is of the object dtype.
is_categorical : Check if the Index holds categorical data.
is_interval : Check if the Index holds Interval objects.
is_mixed : Check if the Index holds data with mixed data types.
Examples
--------
>>> idx = pd.Index([True, False, True])
>>> idx.is_boolean()
True
>>> idx = pd.Index(["True", "False", "True"])
>>> idx.is_boolean()
False
>>> idx = pd.Index([True, False, "True"])
>>> idx.is_boolean()
False
"""
return self.inferred_type in ["boolean"]
def is_integer(self) -> bool:
"""
Check if the Index only consists of integers.
Returns
-------
bool
Whether or not the Index only consists of integers.
See Also
--------
is_boolean : Check if the Index only consists of booleans.
is_floating : Check if the Index is a floating type.
is_numeric : Check if the Index only consists of numeric data.
is_object : Check if the Index is of the object dtype.
is_categorical : Check if the Index holds categorical data.
is_interval : Check if the Index holds Interval objects.
is_mixed : Check if the Index holds data with mixed data types.
Examples
--------
>>> idx = pd.Index([1, 2, 3, 4])
>>> idx.is_integer()
True
>>> idx = pd.Index([1.0, 2.0, 3.0, 4.0])
>>> idx.is_integer()
False
>>> idx = pd.Index(["Apple", "Mango", "Watermelon"])
>>> idx.is_integer()
False
"""
return self.inferred_type in ["integer"]
def is_floating(self) -> bool:
"""
Check if the Index is a floating type.
The Index may consist of only floats, NaNs, or a mix of floats,
integers, or NaNs.
Returns
-------
bool
Whether or not the Index only consists of only consists of floats, NaNs, or
a mix of floats, integers, or NaNs.
See Also
--------
is_boolean : Check if the Index only consists of booleans.
is_integer : Check if the Index only consists of integers.
is_numeric : Check if the Index only consists of numeric data.
is_object : Check if the Index is of the object dtype.
is_categorical : Check if the Index holds categorical data.
is_interval : Check if the Index holds Interval objects.
is_mixed : Check if the Index holds data with mixed data types.
Examples
--------
>>> idx = pd.Index([1.0, 2.0, 3.0, 4.0])
>>> idx.is_floating()
True
>>> idx = pd.Index([1.0, 2.0, np.nan, 4.0])
>>> idx.is_floating()
True
>>> idx = pd.Index([1, 2, 3, 4, np.nan])
>>> idx.is_floating()
True
>>> idx = pd.Index([1, 2, 3, 4])
>>> idx.is_floating()
False
"""
return self.inferred_type in ["floating", "mixed-integer-float", "integer-na"]
def is_numeric(self) -> bool:
"""
Check if the Index only consists of numeric data.
Returns
-------
bool
Whether or not the Index only consists of numeric data.
See Also
--------
is_boolean : Check if the Index only consists of booleans.
is_integer : Check if the Index only consists of integers.
is_floating : Check if the Index is a floating type.
is_object : Check if the Index is of the object dtype.
is_categorical : Check if the Index holds categorical data.
is_interval : Check if the Index holds Interval objects.
is_mixed : Check if the Index holds data with mixed data types.
Examples
--------
>>> idx = pd.Index([1.0, 2.0, 3.0, 4.0])
>>> idx.is_numeric()
True
>>> idx = pd.Index([1, 2, 3, 4.0])
>>> idx.is_numeric()
True
>>> idx = pd.Index([1, 2, 3, 4])
>>> idx.is_numeric()
True
>>> idx = pd.Index([1, 2, 3, 4.0, np.nan])
>>> idx.is_numeric()
True
>>> idx = pd.Index([1, 2, 3, 4.0, np.nan, "Apple"])
>>> idx.is_numeric()
False
"""
return self.inferred_type in ["integer", "floating"]
def is_object(self) -> bool:
"""
Check if the Index is of the object dtype.
Returns
-------
bool
Whether or not the Index is of the object dtype.
See Also
--------
is_boolean : Check if the Index only consists of booleans.
is_integer : Check if the Index only consists of integers.
is_floating : Check if the Index is a floating type.
is_numeric : Check if the Index only consists of numeric data.
is_categorical : Check if the Index holds categorical data.
is_interval : Check if the Index holds Interval objects.
is_mixed : Check if the Index holds data with mixed data types.
Examples
--------
>>> idx = pd.Index(["Apple", "Mango", "Watermelon"])
>>> idx.is_object()
True
>>> idx = pd.Index(["Apple", "Mango", 2.0])
>>> idx.is_object()
True
>>> idx = pd.Index(["Watermelon", "Orange", "Apple",
... "Watermelon"]).astype("category")
>>> idx.object()
False
>>> idx = pd.Index([1.0, 2.0, 3.0, 4.0])
>>> idx.is_object()
False
"""
return is_object_dtype(self.dtype)
def is_categorical(self) -> bool:
"""
Check if the Index holds categorical data.
Returns
-------
bool
True if the Index is categorical.
See Also
--------
CategoricalIndex : Index for categorical data.
is_boolean : Check if the Index only consists of booleans.
is_integer : Check if the Index only consists of integers.
is_floating : Check if the Index is a floating type.
is_numeric : Check if the Index only consists of numeric data.
is_object : Check if the Index is of the object dtype.
is_interval : Check if the Index holds Interval objects.
is_mixed : Check if the Index holds data with mixed data types.
Examples
--------
>>> idx = pd.Index(["Watermelon", "Orange", "Apple",
... "Watermelon"]).astype("category")
>>> idx.is_categorical()
True
>>> idx = pd.Index([1, 3, 5, 7])
>>> idx.is_categorical()
False
>>> s = pd.Series(["Peter", "Victor", "Elisabeth", "Mar"])
>>> s
0 Peter
1 Victor
2 Elisabeth
3 Mar
dtype: object
>>> s.index.is_categorical()
False
"""
return self.inferred_type in ["categorical"]
def is_interval(self) -> bool:
"""
Check if the Index holds Interval objects.
Returns
-------
bool
Whether or not the Index holds Interval objects.
See Also
--------
IntervalIndex : Index for Interval objects.
is_boolean : Check if the Index only consists of booleans.
is_integer : Check if the Index only consists of integers.
is_floating : Check if the Index is a floating type.
is_numeric : Check if the Index only consists of numeric data.
is_object : Check if the Index is of the object dtype.
is_categorical : Check if the Index holds categorical data.
is_mixed : Check if the Index holds data with mixed data types.
Examples
--------
>>> idx = pd.Index([pd.Interval(left=0, right=5),
... pd.Interval(left=5, right=10)])
>>> idx.is_interval()
True
>>> idx = pd.Index([1, 3, 5, 7])
>>> idx.is_interval()
False
"""
return self.inferred_type in ["interval"]
def is_mixed(self) -> bool:
"""
Check if the Index holds data with mixed data types.
Returns
-------
bool
Whether or not the Index holds data with mixed data types.
See Also
--------
is_boolean : Check if the Index only consists of booleans.
is_integer : Check if the Index only consists of integers.
is_floating : Check if the Index is a floating type.
is_numeric : Check if the Index only consists of numeric data.
is_object : Check if the Index is of the object dtype.
is_categorical : Check if the Index holds categorical data.
is_interval : Check if the Index holds Interval objects.
Examples
--------
>>> idx = pd.Index(['a', np.nan, 'b'])
>>> idx.is_mixed()
True
>>> idx = pd.Index([1.0, 2.0, 3.0, 5.0])
>>> idx.is_mixed()
False
"""
return self.inferred_type in ["mixed"]
def holds_integer(self) -> bool:
"""
Whether the type is an integer type.
"""
return self.inferred_type in ["integer", "mixed-integer"]
@cache_readonly
def inferred_type(self) -> str_t:
"""
Return a string of the type inferred from the values.
"""
return lib.infer_dtype(self, skipna=False)
@cache_readonly
def is_all_dates(self) -> bool:
"""
Whether or not the index values only consist of dates.
"""
return is_datetime_array(ensure_object(self.values))
# --------------------------------------------------------------------
# Pickle Methods
def __reduce__(self):
d = dict(data=self._data)
d.update(self._get_attributes_dict())
return _new_Index, (type(self), d), None
# --------------------------------------------------------------------
# Null Handling Methods
_na_value = np.nan
"""The expected NA value to use with this index."""
@cache_readonly
def _isnan(self):
"""
Return if each value is NaN.
"""
if self._can_hold_na:
return isna(self)
else:
# shouldn't reach to this condition by checking hasnans beforehand
values = np.empty(len(self), dtype=np.bool_)
values.fill(False)
return values
@cache_readonly
def _nan_idxs(self):
if self._can_hold_na:
return self._isnan.nonzero()[0]
else:
return np.array([], dtype=np.int64)
@cache_readonly
def hasnans(self) -> bool:
"""
Return if I have any nans; enables various perf speedups.
"""
if self._can_hold_na:
return bool(self._isnan.any())
else:
return False
def isna(self):
"""
Detect missing values.
Return a boolean same-sized object indicating if the values are NA.
NA values, such as ``None``, :attr:`numpy.NaN` or :attr:`pd.NaT`, get
mapped to ``True`` values.
Everything else get mapped to ``False`` values. Characters such as
empty strings `''` or :attr:`numpy.inf` are not considered NA values
(unless you set ``pandas.options.mode.use_inf_as_na = True``).
Returns
-------
numpy.ndarray
A boolean array of whether my values are NA.
See Also
--------
Index.notna : Boolean inverse of isna.
Index.dropna : Omit entries with missing values.
isna : Top-level isna.
Series.isna : Detect missing values in Series object.
Examples
--------
Show which entries in a pandas.Index are NA. The result is an
array.
>>> idx = pd.Index([5.2, 6.0, np.NaN])
>>> idx
Float64Index([5.2, 6.0, nan], dtype='float64')
>>> idx.isna()
array([False, False, True], dtype=bool)
Empty strings are not considered NA values. None is considered an NA
value.
>>> idx = pd.Index(['black', '', 'red', None])
>>> idx
Index(['black', '', 'red', None], dtype='object')
>>> idx.isna()
array([False, False, False, True], dtype=bool)
For datetimes, `NaT` (Not a Time) is considered as an NA value.
>>> idx = pd.DatetimeIndex([pd.Timestamp('1940-04-25'),
... pd.Timestamp(''), None, pd.NaT])
>>> idx
DatetimeIndex(['1940-04-25', 'NaT', 'NaT', 'NaT'],
dtype='datetime64[ns]', freq=None)
>>> idx.isna()
array([False, True, True, True], dtype=bool)
"""
return self._isnan
isnull = isna
def notna(self):
"""
Detect existing (non-missing) values.
Return a boolean same-sized object indicating if the values are not NA.
Non-missing values get mapped to ``True``. Characters such as empty
strings ``''`` or :attr:`numpy.inf` are not considered NA values
(unless you set ``pandas.options.mode.use_inf_as_na = True``).
NA values, such as None or :attr:`numpy.NaN`, get mapped to ``False``
values.
Returns
-------
numpy.ndarray
Boolean array to indicate which entries are not NA.
See Also
--------
Index.notnull : Alias of notna.
Index.isna: Inverse of notna.
notna : Top-level notna.
Examples
--------
Show which entries in an Index are not NA. The result is an
array.
>>> idx = pd.Index([5.2, 6.0, np.NaN])
>>> idx
Float64Index([5.2, 6.0, nan], dtype='float64')
>>> idx.notna()
array([ True, True, False])
Empty strings are not considered NA values. None is considered a NA
value.
>>> idx = pd.Index(['black', '', 'red', None])
>>> idx
Index(['black', '', 'red', None], dtype='object')
>>> idx.notna()
array([ True, True, True, False])
"""
return ~self.isna()
notnull = notna
def fillna(self, value=None, downcast=None):
"""
Fill NA/NaN values with the specified value.
Parameters
----------
value : scalar
Scalar value to use to fill holes (e.g. 0).
This value cannot be a list-likes.
downcast : dict, default is None
a dict of item->dtype of what to downcast if possible,
or the string 'infer' which will try to downcast to an appropriate
equal type (e.g. float64 to int64 if possible).
Returns
-------
filled : Index
"""
self._assert_can_do_op(value)
if self.hasnans:
result = self.putmask(self._isnan, value)
if downcast is None:
# no need to care metadata other than name
# because it can't have freq if
return Index(result, name=self.name)
return self._shallow_copy()
def dropna(self, how="any"):
"""
Return Index without NA/NaN values.
Parameters
----------
how : {'any', 'all'}, default 'any'
If the Index is a MultiIndex, drop the value when any or all levels
are NaN.
Returns
-------
valid : Index
"""
if how not in ("any", "all"):
raise ValueError(f"invalid how option: {how}")
if self.hasnans:
return self._shallow_copy(self._values[~self._isnan])
return self._shallow_copy()
# --------------------------------------------------------------------
# Uniqueness Methods
def unique(self, level=None):
"""
Return unique values in the index. Uniques are returned in order
of appearance, this does NOT sort.
Parameters
----------
level : int or str, optional, default None
Only return values from specified level (for MultiIndex).
.. versionadded:: 0.23.0
Returns
-------
Index without duplicates
See Also
--------
unique
Series.unique
"""
if level is not None:
self._validate_index_level(level)
result = super().unique()
return self._shallow_copy(result)
def drop_duplicates(self, keep="first"):
"""
Return Index with duplicate values removed.
Parameters
----------
keep : {'first', 'last', ``False``}, default 'first'
- 'first' : Drop duplicates except for the first occurrence.
- 'last' : Drop duplicates except for the last occurrence.
- ``False`` : Drop all duplicates.
Returns
-------
deduplicated : Index
See Also
--------
Series.drop_duplicates : Equivalent method on Series.
DataFrame.drop_duplicates : Equivalent method on DataFrame.
Index.duplicated : Related method on Index, indicating duplicate
Index values.
Examples
--------
Generate an pandas.Index with duplicate values.
>>> idx = pd.Index(['lama', 'cow', 'lama', 'beetle', 'lama', 'hippo'])
The `keep` parameter controls which duplicate values are removed.
The value 'first' keeps the first occurrence for each
set of duplicated entries. The default value of keep is 'first'.
>>> idx.drop_duplicates(keep='first')
Index(['lama', 'cow', 'beetle', 'hippo'], dtype='object')
The value 'last' keeps the last occurrence for each set of duplicated
entries.
>>> idx.drop_duplicates(keep='last')
Index(['cow', 'beetle', 'lama', 'hippo'], dtype='object')
The value ``False`` discards all sets of duplicated entries.
>>> idx.drop_duplicates(keep=False)
Index(['cow', 'beetle', 'hippo'], dtype='object')
"""
return super().drop_duplicates(keep=keep)
def duplicated(self, keep="first"):
"""
Indicate duplicate index values.
Duplicated values are indicated as ``True`` values in the resulting
array. Either all duplicates, all except the first, or all except the
last occurrence of duplicates can be indicated.
Parameters
----------
keep : {'first', 'last', False}, default 'first'
The value or values in a set of duplicates to mark as missing.
- 'first' : Mark duplicates as ``True`` except for the first
occurrence.
- 'last' : Mark duplicates as ``True`` except for the last
occurrence.
- ``False`` : Mark all duplicates as ``True``.
Returns
-------
numpy.ndarray
See Also
--------
Series.duplicated : Equivalent method on pandas.Series.
DataFrame.duplicated : Equivalent method on pandas.DataFrame.
Index.drop_duplicates : Remove duplicate values from Index.
Examples
--------
By default, for each set of duplicated values, the first occurrence is
set to False and all others to True:
>>> idx = pd.Index(['lama', 'cow', 'lama', 'beetle', 'lama'])
>>> idx.duplicated()
array([False, False, True, False, True])
which is equivalent to
>>> idx.duplicated(keep='first')
array([False, False, True, False, True])
By using 'last', the last occurrence of each set of duplicated values
is set on False and all others on True:
>>> idx.duplicated(keep='last')
array([ True, False, True, False, False])
By setting keep on ``False``, all duplicates are True:
>>> idx.duplicated(keep=False)
array([ True, False, True, False, True])
"""
return super().duplicated(keep=keep)
def _get_unique_index(self, dropna: bool = False):
"""
Returns an index containing unique values.
Parameters
----------
dropna : bool, default False
If True, NaN values are dropped.
Returns
-------
uniques : index
"""
if self.is_unique and not dropna:
return self
values = self.values
if not self.is_unique:
values = self.unique()
if not isinstance(self, ABCMultiIndex):
# extract an array to pass to _shallow_copy
values = values._data
if dropna:
try:
if self.hasnans:
values = values[~isna(values)]
except NotImplementedError:
pass
return self._shallow_copy(values)
# --------------------------------------------------------------------
# Arithmetic & Logical Methods
def __add__(self, other):
if isinstance(other, (ABCSeries, ABCDataFrame)):
return NotImplemented
from pandas import Series
return Index(Series(self) + other)
def __radd__(self, other):
from pandas import Series
return Index(other + Series(self))
def __iadd__(self, other):
# alias for __add__
return self + other
def __sub__(self, other):
return Index(np.array(self) - other)
def __rsub__(self, other):
# wrap Series to ensure we pin name correctly
from pandas import Series
return Index(other - Series(self))
def __and__(self, other):
return self.intersection(other)
def __or__(self, other):
return self.union(other)
def __xor__(self, other):
return self.symmetric_difference(other)
def __nonzero__(self):
raise ValueError(
f"The truth value of a {type(self).__name__} is ambiguous. "
"Use a.empty, a.bool(), a.item(), a.any() or a.all()."
)
__bool__ = __nonzero__
# --------------------------------------------------------------------
# Set Operation Methods
def _get_reconciled_name_object(self, other):
"""
If the result of a set operation will be self,
return self, unless the name changes, in which
case make a shallow copy of self.
"""
name = get_op_result_name(self, other)
if self.name != name:
return self._shallow_copy(name=name)
return self
def _union_incompatible_dtypes(self, other, sort):
"""
Casts this and other index to object dtype to allow the formation
of a union between incompatible types.
Parameters
----------
other : Index or array-like
sort : False or None, default False
Whether to sort the resulting index.
* False : do not sort the result.
* None : sort the result, except when `self` and `other` are equal
or when the values cannot be compared.
Returns
-------
Index
"""
this = self.astype(object, copy=False)
# cast to Index for when `other` is list-like
other = Index(other).astype(object, copy=False)
return Index.union(this, other, sort=sort).astype(object, copy=False)
def _is_compatible_with_other(self, other) -> bool:
"""
Check whether this and the other dtype are compatible with each other.
Meaning a union can be formed between them without needing to be cast
to dtype object.
Parameters
----------
other : Index or array-like
Returns
-------
bool
"""
return type(self) is type(other) and is_dtype_equal(self.dtype, other.dtype)
def _validate_sort_keyword(self, sort):
if sort not in [None, False]:
raise ValueError(
"The 'sort' keyword only takes the values of "
f"None or False; {sort} was passed."
)
def union(self, other, sort=None):
"""
Form the union of two Index objects.
If the Index objects are incompatible, both Index objects will be
cast to dtype('object') first.
.. versionchanged:: 0.25.0
Parameters
----------
other : Index or array-like
sort : bool or None, default None
Whether to sort the resulting Index.
* None : Sort the result, except when
1. `self` and `other` are equal.
2. `self` or `other` has length 0.
3. Some values in `self` or `other` cannot be compared.
A RuntimeWarning is issued in this case.
* False : do not sort the result.
.. versionadded:: 0.24.0
.. versionchanged:: 0.24.1
Changed the default value from ``True`` to ``None``
(without change in behaviour).
Returns
-------
union : Index
Examples
--------
Union matching dtypes
>>> idx1 = pd.Index([1, 2, 3, 4])
>>> idx2 = pd.Index([3, 4, 5, 6])
>>> idx1.union(idx2)
Int64Index([1, 2, 3, 4, 5, 6], dtype='int64')
Union mismatched dtypes
>>> idx1 = pd.Index(['a', 'b', 'c', 'd'])
>>> idx2 = pd.Index([1, 2, 3, 4])
>>> idx1.union(idx2)
Index(['a', 'b', 'c', 'd', 1, 2, 3, 4], dtype='object')
"""
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
if not self._is_compatible_with_other(other):
return self._union_incompatible_dtypes(other, sort=sort)
return self._union(other, sort=sort)
def _union(self, other, sort):
"""
Specific union logic should go here. In subclasses, union behavior
should be overwritten here rather than in `self.union`.
Parameters
----------
other : Index or array-like
sort : False or None, default False
Whether to sort the resulting index.
* False : do not sort the result.
* None : sort the result, except when `self` and `other` are equal
or when the values cannot be compared.
Returns
-------
Index
"""
if not len(other) or self.equals(other):
return self._get_reconciled_name_object(other)
if not len(self):
return other._get_reconciled_name_object(self)
# TODO(EA): setops-refactor, clean all this up
if is_datetime64tz_dtype(self):
lvals = self._ndarray_values
else:
lvals = self._values
if is_datetime64tz_dtype(other):
rvals = other._ndarray_values
else:
rvals = other._values
if sort is None and self.is_monotonic and other.is_monotonic:
try:
result = self._outer_indexer(lvals, rvals)[0]
except TypeError:
# incomparable objects
result = list(lvals)
# worth making this faster? a very unusual case
value_set = set(lvals)
result.extend([x for x in rvals if x not in value_set])
result = Index(result)._values # do type inference here
else:
# find indexes of things in "other" that are not in "self"
if self.is_unique:
indexer = self.get_indexer(other)
indexer = (indexer == -1).nonzero()[0]
else:
indexer = algos.unique1d(self.get_indexer_non_unique(other)[1])
if len(indexer) > 0:
other_diff = algos.take_nd(rvals, indexer, allow_fill=False)
result = concat_compat((lvals, other_diff))
else:
result = lvals
if sort is None:
try:
result = algos.safe_sort(result)
except TypeError as err:
warnings.warn(
f"{err}, sort order is undefined for incomparable objects",
RuntimeWarning,
stacklevel=3,
)
# for subclasses
return self._wrap_setop_result(other, result)
def _wrap_setop_result(self, other, result):
name = get_op_result_name(self, other)
return self._shallow_copy(result, name=name)
# TODO: standardize return type of non-union setops type(self vs other)
def intersection(self, other, sort=False):
"""
Form the intersection of two Index objects.
This returns a new Index with elements common to the index and `other`.
Parameters
----------
other : Index or array-like
sort : False or None, default False
Whether to sort the resulting index.
* False : do not sort the result.
* None : sort the result, except when `self` and `other` are equal
or when the values cannot be compared.
.. versionadded:: 0.24.0
.. versionchanged:: 0.24.1
Changed the default from ``True`` to ``False``, to match
the behaviour of 0.23.4 and earlier.
Returns
-------
intersection : Index
Examples
--------
>>> idx1 = pd.Index([1, 2, 3, 4])
>>> idx2 = pd.Index([3, 4, 5, 6])
>>> idx1.intersection(idx2)
Int64Index([3, 4], dtype='int64')
"""
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
other = ensure_index(other)
if self.equals(other):
return self._get_reconciled_name_object(other)
if not is_dtype_equal(self.dtype, other.dtype):
this = self.astype("O")
other = other.astype("O")
return this.intersection(other, sort=sort)
# TODO(EA): setops-refactor, clean all this up
lvals = self._values
rvals = other._values
if self.is_monotonic and other.is_monotonic:
try:
result = self._inner_indexer(lvals, rvals)[0]
except TypeError:
pass
else:
return self._wrap_setop_result(other, result)
try:
indexer = Index(rvals).get_indexer(lvals)
indexer = indexer.take((indexer != -1).nonzero()[0])
except (InvalidIndexError, IncompatibleFrequency):
# InvalidIndexError raised by get_indexer if non-unique
# IncompatibleFrequency raised by PeriodIndex.get_indexer
indexer = algos.unique1d(Index(rvals).get_indexer_non_unique(lvals)[0])
indexer = indexer[indexer != -1]
taken = other.take(indexer)
res_name = get_op_result_name(self, other)
if sort is None:
taken = algos.safe_sort(taken.values)
return self._shallow_copy(taken, name=res_name)
taken.name = res_name
return taken
def difference(self, other, sort=None):
"""
Return a new Index with elements from the index that are not in
`other`.
This is the set difference of two Index objects.
Parameters
----------
other : Index or array-like
sort : False or None, default None
Whether to sort the resulting index. By default, the
values are attempted to be sorted, but any TypeError from
incomparable elements is caught by pandas.
* None : Attempt to sort the result, but catch any TypeErrors
from comparing incomparable elements.
* False : Do not sort the result.
.. versionadded:: 0.24.0
.. versionchanged:: 0.24.1
Changed the default value from ``True`` to ``None``
(without change in behaviour).
Returns
-------
difference : Index
Examples
--------
>>> idx1 = pd.Index([2, 1, 3, 4])
>>> idx2 = pd.Index([3, 4, 5, 6])
>>> idx1.difference(idx2)
Int64Index([1, 2], dtype='int64')
>>> idx1.difference(idx2, sort=False)
Int64Index([2, 1], dtype='int64')
"""
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
if self.equals(other):
# pass an empty np.ndarray with the appropriate dtype
return self._shallow_copy(self._data[:0])
other, result_name = self._convert_can_do_setop(other)
this = self._get_unique_index()
indexer = this.get_indexer(other)
indexer = indexer.take((indexer != -1).nonzero()[0])
label_diff = np.setdiff1d(np.arange(this.size), indexer, assume_unique=True)
the_diff = this.values.take(label_diff)
if sort is None:
try:
the_diff = algos.safe_sort(the_diff)
except TypeError:
pass
return this._shallow_copy(the_diff, name=result_name)
def symmetric_difference(self, other, result_name=None, sort=None):
"""
Compute the symmetric difference of two Index objects.
Parameters
----------
other : Index or array-like
result_name : str
sort : False or None, default None
Whether to sort the resulting index. By default, the
values are attempted to be sorted, but any TypeError from
incomparable elements is caught by pandas.
* None : Attempt to sort the result, but catch any TypeErrors
from comparing incomparable elements.
* False : Do not sort the result.
.. versionadded:: 0.24.0
.. versionchanged:: 0.24.1
Changed the default value from ``True`` to ``None``
(without change in behaviour).
Returns
-------
symmetric_difference : Index
Notes
-----
``symmetric_difference`` contains elements that appear in either
``idx1`` or ``idx2`` but not both. Equivalent to the Index created by
``idx1.difference(idx2) | idx2.difference(idx1)`` with duplicates
dropped.
Examples
--------
>>> idx1 = pd.Index([1, 2, 3, 4])
>>> idx2 = pd.Index([2, 3, 4, 5])
>>> idx1.symmetric_difference(idx2)
Int64Index([1, 5], dtype='int64')
You can also use the ``^`` operator:
>>> idx1 ^ idx2
Int64Index([1, 5], dtype='int64')
"""
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
other, result_name_update = self._convert_can_do_setop(other)
if result_name is None:
result_name = result_name_update
this = self._get_unique_index()
other = other._get_unique_index()
indexer = this.get_indexer(other)
# {this} minus {other}
common_indexer = indexer.take((indexer != -1).nonzero()[0])
left_indexer = np.setdiff1d(
np.arange(this.size), common_indexer, assume_unique=True
)
left_diff = this._values.take(left_indexer)
# {other} minus {this}
right_indexer = (indexer == -1).nonzero()[0]
right_diff = other._values.take(right_indexer)
the_diff = concat_compat([left_diff, right_diff])
if sort is None:
try:
the_diff = algos.safe_sort(the_diff)
except TypeError:
pass
attribs = self._get_attributes_dict()
attribs["name"] = result_name
if "freq" in attribs:
attribs["freq"] = None
return self._shallow_copy_with_infer(the_diff, **attribs)
def _assert_can_do_setop(self, other):
if not is_list_like(other):
raise TypeError("Input must be Index or array-like")
return True
def _convert_can_do_setop(self, other):
if not isinstance(other, Index):
other = Index(other, name=self.name)
result_name = self.name
else:
result_name = get_op_result_name(self, other)
return other, result_name
# --------------------------------------------------------------------
# Indexing Methods
def get_loc(self, key, method=None, tolerance=None):
"""
Get integer location, slice or boolean mask for requested label.
Parameters
----------
key : label
method : {None, 'pad'/'ffill', 'backfill'/'bfill', 'nearest'}, optional
* default: exact matches only.
* pad / ffill: find the PREVIOUS index value if no exact match.
* backfill / bfill: use NEXT index value if no exact match
* nearest: use the NEAREST index value if no exact match. Tied
distances are broken by preferring the larger index value.
tolerance : int or float, optional
Maximum distance from index value for inexact matches. The value of
the index at the matching location most satisfy the equation
``abs(index[loc] - key) <= tolerance``.
.. versionadded:: 0.21.0 (list-like tolerance)
Returns
-------
loc : int if unique index, slice if monotonic index, else mask
Examples
--------
>>> unique_index = pd.Index(list('abc'))
>>> unique_index.get_loc('b')
1
>>> monotonic_index = pd.Index(list('abbc'))
>>> monotonic_index.get_loc('b')
slice(1, 3, None)
>>> non_monotonic_index = pd.Index(list('abcb'))
>>> non_monotonic_index.get_loc('b')
array([False, True, False, True], dtype=bool)
"""
if method is None:
if tolerance is not None:
raise ValueError(
"tolerance argument only valid if using pad, "
"backfill or nearest lookups"
)
casted_key = self._maybe_cast_indexer(key)
try:
return self._engine.get_loc(casted_key)
except KeyError:
raise KeyError(key)
if tolerance is not None:
tolerance = self._convert_tolerance(tolerance, np.asarray(key))
indexer = self.get_indexer([key], method=method, tolerance=tolerance)
if indexer.ndim > 1 or indexer.size > 1:
raise TypeError("get_loc requires scalar valued input")
loc = indexer.item()
if loc == -1:
raise KeyError(key)
return loc
_index_shared_docs[
"get_indexer"
] = """
Compute indexer and mask for new index given the current index. The
indexer should be then used as an input to ndarray.take to align the
current data to the new index.
Parameters
----------
target : %(target_klass)s
method : {None, 'pad'/'ffill', 'backfill'/'bfill', 'nearest'}, optional
* default: exact matches only.
* pad / ffill: find the PREVIOUS index value if no exact match.
* backfill / bfill: use NEXT index value if no exact match
* nearest: use the NEAREST index value if no exact match. Tied
distances are broken by preferring the larger index value.
limit : int, optional
Maximum number of consecutive labels in ``target`` to match for
inexact matches.
tolerance : optional
Maximum distance between original and new labels for inexact
matches. The values of the index at the matching locations most
satisfy the equation ``abs(index[indexer] - target) <= tolerance``.
Tolerance may be a scalar value, which applies the same tolerance
to all values, or list-like, which applies variable tolerance per
element. List-like includes list, tuple, array, Series, and must be
the same size as the index and its dtype must exactly match the
index's type.
.. versionadded:: 0.21.0 (list-like tolerance)
Returns
-------
indexer : ndarray of int
Integers from 0 to n - 1 indicating that the index at these
positions matches the corresponding target values. Missing values
in the target are marked by -1.
%(raises_section)s
Examples
--------
>>> index = pd.Index(['c', 'a', 'b'])
>>> index.get_indexer(['a', 'b', 'x'])
array([ 1, 2, -1])
Notice that the return value is an array of locations in ``index``
and ``x`` is marked by -1, as it is not in ``index``.
"""
@Appender(_index_shared_docs["get_indexer"] % _index_doc_kwargs)
def get_indexer(
self, target, method=None, limit=None, tolerance=None
) -> np.ndarray:
method = missing.clean_reindex_fill_method(method)
target = ensure_index(target)
if tolerance is not None:
tolerance = self._convert_tolerance(tolerance, target)
# Treat boolean labels passed to a numeric index as not found. Without
# this fix False and True would be treated as 0 and 1 respectively.
# (GH #16877)
if target.is_boolean() and self.is_numeric():
return ensure_platform_int(np.repeat(-1, target.size))
pself, ptarget = self._maybe_promote(target)
if pself is not self or ptarget is not target:
return pself.get_indexer(
ptarget, method=method, limit=limit, tolerance=tolerance
)
if not is_dtype_equal(self.dtype, target.dtype):
this = self.astype(object)
target = target.astype(object)
return this.get_indexer(
target, method=method, limit=limit, tolerance=tolerance
)
if not self.is_unique:
raise InvalidIndexError(
"Reindexing only valid with uniquely valued Index objects"
)
if method == "pad" or method == "backfill":
indexer = self._get_fill_indexer(target, method, limit, tolerance)
elif method == "nearest":
indexer = self._get_nearest_indexer(target, limit, tolerance)
else:
if tolerance is not None:
raise ValueError(
"tolerance argument only valid if doing pad, "
"backfill or nearest reindexing"
)
if limit is not None:
raise ValueError(
"limit argument only valid if doing pad, "
"backfill or nearest reindexing"
)
indexer = self._engine.get_indexer(target._ndarray_values)
return ensure_platform_int(indexer)
def _convert_tolerance(self, tolerance, target):
# override this method on subclasses
tolerance = np.asarray(tolerance)
if target.size != tolerance.size and tolerance.size > 1:
raise ValueError("list-like tolerance size must match target index size")
return tolerance
def _get_fill_indexer(
self, target: "Index", method: str_t, limit=None, tolerance=None
) -> np.ndarray:
if self.is_monotonic_increasing and target.is_monotonic_increasing:
engine_method = (
self._engine.get_pad_indexer
if method == "pad"
else self._engine.get_backfill_indexer
)
indexer = engine_method(target._ndarray_values, limit)
else:
indexer = self._get_fill_indexer_searchsorted(target, method, limit)
if tolerance is not None:
indexer = self._filter_indexer_tolerance(
target._ndarray_values, indexer, tolerance
)
return indexer
def _get_fill_indexer_searchsorted(
self, target: "Index", method: str_t, limit=None
) -> np.ndarray:
"""
Fallback pad/backfill get_indexer that works for monotonic decreasing
indexes and non-monotonic targets.
"""
if limit is not None:
raise ValueError(
f"limit argument for {repr(method)} method only well-defined "
"if index and target are monotonic"
)
side = "left" if method == "pad" else "right"
# find exact matches first (this simplifies the algorithm)
indexer = self.get_indexer(target)
nonexact = indexer == -1
indexer[nonexact] = self._searchsorted_monotonic(target[nonexact], side)
if side == "left":
# searchsorted returns "indices into a sorted array such that,
# if the corresponding elements in v were inserted before the
# indices, the order of a would be preserved".
# Thus, we need to subtract 1 to find values to the left.
indexer[nonexact] -= 1
# This also mapped not found values (values of 0 from
# np.searchsorted) to -1, which conveniently is also our
# sentinel for missing values
else:
# Mark indices to the right of the largest value as not found
indexer[indexer == len(self)] = -1
return indexer
def _get_nearest_indexer(self, target: "Index", limit, tolerance) -> np.ndarray:
"""
Get the indexer for the nearest index labels; requires an index with
values that can be subtracted from each other (e.g., not strings or
tuples).
"""
left_indexer = self.get_indexer(target, "pad", limit=limit)
right_indexer = self.get_indexer(target, "backfill", limit=limit)
left_distances = np.abs(self[left_indexer] - target)
right_distances = np.abs(self[right_indexer] - target)
op = operator.lt if self.is_monotonic_increasing else operator.le
indexer = np.where(
op(left_distances, right_distances) | (right_indexer == -1),
left_indexer,
right_indexer,
)
if tolerance is not None:
indexer = self._filter_indexer_tolerance(target, indexer, tolerance)
return indexer
def _filter_indexer_tolerance(
self, target: "Index", indexer: np.ndarray, tolerance
) -> np.ndarray:
distance = abs(self.values[indexer] - target)
indexer = np.where(distance <= tolerance, indexer, -1)
return indexer
# --------------------------------------------------------------------
# Indexer Conversion Methods
def _get_partial_string_timestamp_match_key(self, key):
"""
Translate any partial string timestamp matches in key, returning the
new key.
Only relevant for MultiIndex.
"""
# GH#10331
return key
def _convert_scalar_indexer(self, key, kind: str_t):
"""
Convert a scalar indexer.
Parameters
----------
key : label of the slice bound
kind : {'loc', 'getitem'}
"""
assert kind in ["loc", "getitem"]
if len(self) and not isinstance(self, ABCMultiIndex):
# we can raise here if we are definitive that this
# is positional indexing (eg. .loc on with a float)
# or label indexing if we are using a type able
# to be represented in the index
if kind == "getitem" and is_float(key):
if not self.is_floating():
self._invalid_indexer("label", key)
elif kind == "loc" and is_float(key):
# we want to raise KeyError on string/mixed here
# technically we *could* raise a TypeError
# on anything but mixed though
if self.inferred_type not in [
"floating",
"mixed-integer-float",
"integer-na",
"string",
"mixed",
]:
self._invalid_indexer("label", key)
elif kind == "loc" and is_integer(key):
if not (is_integer_dtype(self.dtype) or is_object_dtype(self.dtype)):
self._invalid_indexer("label", key)
return key
def _validate_positional_slice(self, key: slice):
"""
For positional indexing, a slice must have either int or None
for each of start, stop, and step.
"""
self._validate_indexer("positional", key.start, "iloc")
self._validate_indexer("positional", key.stop, "iloc")
self._validate_indexer("positional", key.step, "iloc")
def _convert_slice_indexer(self, key: slice, kind: str_t):
"""
Convert a slice indexer.
By definition, these are labels unless 'iloc' is passed in.
Floats are not allowed as the start, step, or stop of the slice.
Parameters
----------
key : label of the slice bound
kind : {'loc', 'getitem'}
"""
assert kind in ["loc", "getitem"], kind
# potentially cast the bounds to integers
start, stop, step = key.start, key.stop, key.step
# figure out if this is a positional indexer
def is_int(v):
return v is None or is_integer(v)
is_null_slicer = start is None and stop is None
is_index_slice = is_int(start) and is_int(stop)
is_positional = is_index_slice and not (
self.is_integer() or self.is_categorical()
)
if kind == "getitem":
"""
called from the getitem slicers, validate that we are in fact
integers
"""
if self.is_integer() or is_index_slice:
self._validate_indexer("slice", key.start, "getitem")
self._validate_indexer("slice", key.stop, "getitem")
self._validate_indexer("slice", key.step, "getitem")
return key
# convert the slice to an indexer here
# if we are mixed and have integers
if is_positional and self.is_mixed():
try:
# Validate start & stop
if start is not None:
self.get_loc(start)
if stop is not None:
self.get_loc(stop)
is_positional = False
except KeyError:
pass
if is_null_slicer:
indexer = key
elif is_positional:
indexer = key
else:
indexer = self.slice_indexer(start, stop, step, kind=kind)
return indexer
def _convert_listlike_indexer(self, keyarr):
"""
Parameters
----------
keyarr : list-like
Indexer to convert.
Returns
-------
indexer : numpy.ndarray or None
Return an ndarray or None if cannot convert.
keyarr : numpy.ndarray
Return tuple-safe keys.
"""
if isinstance(keyarr, Index):
keyarr = self._convert_index_indexer(keyarr)
else:
keyarr = self._convert_arr_indexer(keyarr)
indexer = self._convert_list_indexer(keyarr)
return indexer, keyarr
def _convert_arr_indexer(self, keyarr):
"""
Convert an array-like indexer to the appropriate dtype.
Parameters
----------
keyarr : array-like
Indexer to convert.
Returns
-------
converted_keyarr : array-like
"""
keyarr = com.asarray_tuplesafe(keyarr)
return keyarr
def _convert_index_indexer(self, keyarr):
"""
Convert an Index indexer to the appropriate dtype.
Parameters
----------
keyarr : Index (or sub-class)
Indexer to convert.
Returns
-------
converted_keyarr : Index (or sub-class)
"""
return keyarr
def _convert_list_indexer(self, keyarr):
"""
Convert a list-like indexer to the appropriate dtype.
Parameters
----------
keyarr : Index (or sub-class)
Indexer to convert.
kind : iloc, loc, optional
Returns
-------
positional indexer or None
"""
return None
def _invalid_indexer(self, form: str_t, key):
"""
Consistent invalid indexer message.
"""
raise TypeError(
f"cannot do {form} indexing on {type(self).__name__} with these "
f"indexers [{key}] of type {type(key).__name__}"
)
# --------------------------------------------------------------------
# Reindex Methods
def _can_reindex(self, indexer):
"""
Check if we are allowing reindexing with this particular indexer.
Parameters
----------
indexer : an integer indexer
Raises
------
ValueError if its a duplicate axis
"""
# trying to reindex on an axis with duplicates
if not self.is_unique and len(indexer):
raise ValueError("cannot reindex from a duplicate axis")
def reindex(self, target, method=None, level=None, limit=None, tolerance=None):
"""
Create index with target's values (move/add/delete values
as necessary).
Parameters
----------
target : an iterable
Returns
-------
new_index : pd.Index
Resulting index.
indexer : np.ndarray or None
Indices of output values in original index.
"""
# GH6552: preserve names when reindexing to non-named target
# (i.e. neither Index nor Series).
preserve_names = not hasattr(target, "name")
# GH7774: preserve dtype/tz if target is empty and not an Index.
target = _ensure_has_len(target) # target may be an iterator
if not isinstance(target, Index) and len(target) == 0:
attrs = self._get_attributes_dict()
attrs.pop("freq", None) # don't preserve freq
if isinstance(self, ABCRangeIndex):
values = range(0)
else:
values = self._data[:0] # appropriately-dtyped empty array
target = self._simple_new(values, dtype=self.dtype, **attrs)
else:
target = ensure_index(target)
if level is not None:
if method is not None:
raise TypeError("Fill method not supported if level passed")
_, indexer, _ = self._join_level(
target, level, how="right", return_indexers=True
)
else:
if self.equals(target):
indexer = None
else:
# check is_overlapping for IntervalIndex compat
if self.is_unique and not getattr(self, "is_overlapping", False):
indexer = self.get_indexer(
target, method=method, limit=limit, tolerance=tolerance
)
else:
if method is not None or limit is not None:
raise ValueError(
"cannot reindex a non-unique index "
"with a method or limit"
)
indexer, missing = self.get_indexer_non_unique(target)
if preserve_names and target.nlevels == 1 and target.name != self.name:
target = target.copy()
target.name = self.name
return target, indexer
def _reindex_non_unique(self, target):
"""
Create a new index with target's values (move/add/delete values as
necessary) use with non-unique Index and a possibly non-unique target.
Parameters
----------
target : an iterable
Returns
-------
new_index : pd.Index
Resulting index.
indexer : np.ndarray or None
Indices of output values in original index.
"""
target = ensure_index(target)
indexer, missing = self.get_indexer_non_unique(target)
check = indexer != -1
new_labels = self.take(indexer[check])
new_indexer = None
if len(missing):
length = np.arange(len(indexer))
missing = ensure_platform_int(missing)
missing_labels = target.take(missing)
missing_indexer = ensure_int64(length[~check])
cur_labels = self.take(indexer[check]).values
cur_indexer = ensure_int64(length[check])
new_labels = np.empty(tuple([len(indexer)]), dtype=object)
new_labels[cur_indexer] = cur_labels
new_labels[missing_indexer] = missing_labels
# a unique indexer
if target.is_unique:
# see GH5553, make sure we use the right indexer
new_indexer = np.arange(len(indexer))
new_indexer[cur_indexer] = np.arange(len(cur_labels))
new_indexer[missing_indexer] = -1
# we have a non_unique selector, need to use the original
# indexer here
else:
# need to retake to have the same size as the indexer
indexer[~check] = -1
# reset the new indexer to account for the new size
new_indexer = np.arange(len(self.take(indexer)))
new_indexer[~check] = -1
new_index = self._shallow_copy_with_infer(new_labels)
return new_index, indexer, new_indexer
# --------------------------------------------------------------------
# Join Methods
def join(self, other, how="left", level=None, return_indexers=False, sort=False):
"""
Compute join_index and indexers to conform data
structures to the new index.
Parameters
----------
other : Index
how : {'left', 'right', 'inner', 'outer'}
level : int or level name, default None
return_indexers : bool, default False
sort : bool, default False
Sort the join keys lexicographically in the result Index. If False,
the order of the join keys depends on the join type (how keyword).
Returns
-------
join_index, (left_indexer, right_indexer)
"""
self_is_mi = isinstance(self, ABCMultiIndex)
other_is_mi = isinstance(other, ABCMultiIndex)
# try to figure out the join level
# GH3662
if level is None and (self_is_mi or other_is_mi):
# have the same levels/names so a simple join
if self.names == other.names:
pass
else:
return self._join_multi(other, how=how, return_indexers=return_indexers)
# join on the level
if level is not None and (self_is_mi or other_is_mi):
return self._join_level(
other, level, how=how, return_indexers=return_indexers
)
other = ensure_index(other)
if len(other) == 0 and how in ("left", "outer"):
join_index = self._shallow_copy()
if return_indexers:
rindexer = np.repeat(-1, len(join_index))
return join_index, None, rindexer
else:
return join_index
if len(self) == 0 and how in ("right", "outer"):
join_index = other._shallow_copy()
if return_indexers:
lindexer = np.repeat(-1, len(join_index))
return join_index, lindexer, None
else:
return join_index
if self._join_precedence < other._join_precedence:
how = {"right": "left", "left": "right"}.get(how, how)
result = other.join(
self, how=how, level=level, return_indexers=return_indexers
)
if return_indexers:
x, y, z = result
result = x, z, y
return result
if not is_dtype_equal(self.dtype, other.dtype):
this = self.astype("O")
other = other.astype("O")
return this.join(other, how=how, return_indexers=return_indexers)
_validate_join_method(how)
if not self.is_unique and not other.is_unique:
return self._join_non_unique(
other, how=how, return_indexers=return_indexers
)
elif not self.is_unique or not other.is_unique:
if self.is_monotonic and other.is_monotonic:
return self._join_monotonic(
other, how=how, return_indexers=return_indexers
)
else:
return self._join_non_unique(
other, how=how, return_indexers=return_indexers
)
elif self.is_monotonic and other.is_monotonic:
try:
return self._join_monotonic(
other, how=how, return_indexers=return_indexers
)
except TypeError:
pass
if how == "left":
join_index = self
elif how == "right":
join_index = other
elif how == "inner":
# TODO: sort=False here for backwards compat. It may
# be better to use the sort parameter passed into join
join_index = self.intersection(other, sort=False)
elif how == "outer":
# TODO: sort=True here for backwards compat. It may
# be better to use the sort parameter passed into join
join_index = self.union(other)
if sort:
join_index = join_index.sort_values()
if return_indexers:
if join_index is self:
lindexer = None
else:
lindexer = self.get_indexer(join_index)
if join_index is other:
rindexer = None
else:
rindexer = other.get_indexer(join_index)
return join_index, lindexer, rindexer
else:
return join_index
def _join_multi(self, other, how, return_indexers=True):
from pandas.core.indexes.multi import MultiIndex
from pandas.core.reshape.merge import _restore_dropped_levels_multijoin
# figure out join names
self_names = set(com.not_none(*self.names))
other_names = set(com.not_none(*other.names))
overlap = self_names & other_names
# need at least 1 in common
if not overlap:
raise ValueError("cannot join with no overlapping index names")
self_is_mi = isinstance(self, ABCMultiIndex)
other_is_mi = isinstance(other, ABCMultiIndex)
if self_is_mi and other_is_mi:
# Drop the non-matching levels from left and right respectively
ldrop_names = list(self_names - overlap)
rdrop_names = list(other_names - overlap)
# if only the order differs
if not len(ldrop_names + rdrop_names):
self_jnlevels = self
other_jnlevels = other.reorder_levels(self.names)
else:
self_jnlevels = self.droplevel(ldrop_names)
other_jnlevels = other.droplevel(rdrop_names)
# Join left and right
# Join on same leveled multi-index frames is supported
join_idx, lidx, ridx = self_jnlevels.join(
other_jnlevels, how, return_indexers=True
)
# Restore the dropped levels
# Returned index level order is
# common levels, ldrop_names, rdrop_names
dropped_names = ldrop_names + rdrop_names
levels, codes, names = _restore_dropped_levels_multijoin(
self, other, dropped_names, join_idx, lidx, ridx
)
# Re-create the multi-index
multi_join_idx = MultiIndex(
levels=levels, codes=codes, names=names, verify_integrity=False
)
multi_join_idx = multi_join_idx.remove_unused_levels()
return multi_join_idx, lidx, ridx
jl = list(overlap)[0]
# Case where only one index is multi
# make the indices into mi's that match
flip_order = False
if self_is_mi:
self, other = other, self
flip_order = True
# flip if join method is right or left
how = {"right": "left", "left": "right"}.get(how, how)
level = other.names.index(jl)
result = self._join_level(
other, level, how=how, return_indexers=return_indexers
)
if flip_order:
if isinstance(result, tuple):
return result[0], result[2], result[1]
return result
def _join_non_unique(self, other, how="left", return_indexers=False):
from pandas.core.reshape.merge import _get_join_indexers
left_idx, right_idx = _get_join_indexers(
[self._ndarray_values], [other._ndarray_values], how=how, sort=True
)
left_idx = ensure_platform_int(left_idx)
right_idx = ensure_platform_int(right_idx)
join_index = np.asarray(self._ndarray_values.take(left_idx))
mask = left_idx == -1
np.putmask(join_index, mask, other._ndarray_values.take(right_idx))
join_index = self._wrap_joined_index(join_index, other)
if return_indexers:
return join_index, left_idx, right_idx
else:
return join_index
def _join_level(
self, other, level, how="left", return_indexers=False, keep_order=True
):
"""
The join method *only* affects the level of the resulting
MultiIndex. Otherwise it just exactly aligns the Index data to the
labels of the level in the MultiIndex.
If ```keep_order == True```, the order of the data indexed by the
MultiIndex will not be changed; otherwise, it will tie out
with `other`.
"""
from pandas.core.indexes.multi import MultiIndex
def _get_leaf_sorter(labels):
"""
Returns sorter for the inner most level while preserving the
order of higher levels.
"""
if labels[0].size == 0:
return np.empty(0, dtype="int64")
if len(labels) == 1:
lab = ensure_int64(labels[0])
sorter, _ = libalgos.groupsort_indexer(lab, 1 + lab.max())
return sorter
# find indexers of beginning of each set of
# same-key labels w.r.t all but last level
tic = labels[0][:-1] != labels[0][1:]
for lab in labels[1:-1]:
tic |= lab[:-1] != lab[1:]
starts = np.hstack(([True], tic, [True])).nonzero()[0]
lab = ensure_int64(labels[-1])
return lib.get_level_sorter(lab, ensure_int64(starts))
if isinstance(self, MultiIndex) and isinstance(other, MultiIndex):
raise TypeError("Join on level between two MultiIndex objects is ambiguous")
left, right = self, other
flip_order = not isinstance(self, MultiIndex)
if flip_order:
left, right = right, left
how = {"right": "left", "left": "right"}.get(how, how)
level = left._get_level_number(level)
old_level = left.levels[level]
if not right.is_unique:
raise NotImplementedError(
"Index._join_level on non-unique index is not implemented"
)
new_level, left_lev_indexer, right_lev_indexer = old_level.join(
right, how=how, return_indexers=True
)
if left_lev_indexer is None:
if keep_order or len(left) == 0:
left_indexer = None
join_index = left
else: # sort the leaves
left_indexer = _get_leaf_sorter(left.codes[: level + 1])
join_index = left[left_indexer]
else:
left_lev_indexer = ensure_int64(left_lev_indexer)
rev_indexer = lib.get_reverse_indexer(left_lev_indexer, len(old_level))
new_lev_codes = algos.take_nd(
rev_indexer, left.codes[level], allow_fill=False
)
new_codes = list(left.codes)
new_codes[level] = new_lev_codes
new_levels = list(left.levels)
new_levels[level] = new_level
if keep_order: # just drop missing values. o.w. keep order
left_indexer = np.arange(len(left), dtype=np.intp)
mask = new_lev_codes != -1
if not mask.all():
new_codes = [lab[mask] for lab in new_codes]
left_indexer = left_indexer[mask]
else: # tie out the order with other
if level == 0: # outer most level, take the fast route
ngroups = 1 + new_lev_codes.max()
left_indexer, counts = libalgos.groupsort_indexer(
new_lev_codes, ngroups
)
# missing values are placed first; drop them!
left_indexer = left_indexer[counts[0] :]
new_codes = [lab[left_indexer] for lab in new_codes]
else: # sort the leaves
mask = new_lev_codes != -1
mask_all = mask.all()
if not mask_all:
new_codes = [lab[mask] for lab in new_codes]
left_indexer = _get_leaf_sorter(new_codes[: level + 1])
new_codes = [lab[left_indexer] for lab in new_codes]
# left_indexers are w.r.t masked frame.
# reverse to original frame!
if not mask_all:
left_indexer = mask.nonzero()[0][left_indexer]
join_index = MultiIndex(
levels=new_levels,
codes=new_codes,
names=left.names,
verify_integrity=False,
)
if right_lev_indexer is not None:
right_indexer = algos.take_nd(
right_lev_indexer, join_index.codes[level], allow_fill=False
)
else:
right_indexer = join_index.codes[level]
if flip_order:
left_indexer, right_indexer = right_indexer, left_indexer
if return_indexers:
left_indexer = (
None if left_indexer is None else ensure_platform_int(left_indexer)
)
right_indexer = (
None if right_indexer is None else ensure_platform_int(right_indexer)
)
return join_index, left_indexer, right_indexer
else:
return join_index
def _join_monotonic(self, other, how="left", return_indexers=False):
if self.equals(other):
ret_index = other if how == "right" else self
if return_indexers:
return ret_index, None, None
else:
return ret_index
sv = self._ndarray_values
ov = other._ndarray_values
if self.is_unique and other.is_unique:
# We can perform much better than the general case
if how == "left":
join_index = self
lidx = None
ridx = self._left_indexer_unique(sv, ov)
elif how == "right":
join_index = other
lidx = self._left_indexer_unique(ov, sv)
ridx = None
elif how == "inner":
join_index, lidx, ridx = self._inner_indexer(sv, ov)
join_index = self._wrap_joined_index(join_index, other)
elif how == "outer":
join_index, lidx, ridx = self._outer_indexer(sv, ov)
join_index = self._wrap_joined_index(join_index, other)
else:
if how == "left":
join_index, lidx, ridx = self._left_indexer(sv, ov)
elif how == "right":
join_index, ridx, lidx = self._left_indexer(ov, sv)
elif how == "inner":
join_index, lidx, ridx = self._inner_indexer(sv, ov)
elif how == "outer":
join_index, lidx, ridx = self._outer_indexer(sv, ov)
join_index = self._wrap_joined_index(join_index, other)
if return_indexers:
lidx = None if lidx is None else ensure_platform_int(lidx)
ridx = None if ridx is None else ensure_platform_int(ridx)
return join_index, lidx, ridx
else:
return join_index
def _wrap_joined_index(self, joined, other):
name = get_op_result_name(self, other)
return Index(joined, name=name)
# --------------------------------------------------------------------
# Uncategorized Methods
@property
def values(self) -> np.ndarray:
"""
Return an array representing the data in the Index.
.. warning::
We recommend using :attr:`Index.array` or
:meth:`Index.to_numpy`, depending on whether you need
a reference to the underlying data or a NumPy array.
Returns
-------
array: numpy.ndarray or ExtensionArray
See Also
--------
Index.array : Reference to the underlying data.
Index.to_numpy : A NumPy array representing the underlying data.
"""
return self._data.view(np.ndarray)
@cache_readonly
@Appender(IndexOpsMixin.array.__doc__) # type: ignore
def array(self) -> ExtensionArray:
array = self._data
if isinstance(array, np.ndarray):
from pandas.core.arrays.numpy_ import PandasArray
array = PandasArray(array)
return array
@property
def _values(self) -> Union[ExtensionArray, np.ndarray]:
"""
The best array representation.
This is an ndarray or ExtensionArray. This differs from
``_ndarray_values``, which always returns an ndarray.
Both ``_values`` and ``_ndarray_values`` are consistent between
``Series`` and ``Index`` (except for datetime64[ns], which returns
a DatetimeArray for _values on the Index, but ndarray[M8ns] on the
Series).
It may differ from the public '.values' method.
index | values | _values | _ndarray_values |
----------------- | --------------- | ------------- | --------------- |
Index | ndarray | ndarray | ndarray |
CategoricalIndex | Categorical | Categorical | ndarray[int] |
DatetimeIndex | ndarray[M8ns] | DatetimeArray | ndarray[M8ns] |
DatetimeIndex[tz] | ndarray[M8ns] | DatetimeArray | ndarray[M8ns] |
PeriodIndex | ndarray[object] | PeriodArray | ndarray[int] |
IntervalIndex | IntervalArray | IntervalArray | ndarray[object] |
See Also
--------
values
_ndarray_values
"""
return self._data
def _internal_get_values(self) -> np.ndarray:
"""
Return `Index` data as an `numpy.ndarray`.
Returns
-------
numpy.ndarray
A one-dimensional numpy array of the `Index` values.
See Also
--------
Index.values : The attribute that _internal_get_values wraps.
Examples
--------
Getting the `Index` values of a `DataFrame`:
>>> df = pd.DataFrame([[1, 2, 3], [4, 5, 6], [7, 8, 9]],
... index=['a', 'b', 'c'], columns=['A', 'B', 'C'])
>>> df
A B C
a 1 2 3
b 4 5 6
c 7 8 9
>>> df.index._internal_get_values()
array(['a', 'b', 'c'], dtype=object)
Standalone `Index` values:
>>> idx = pd.Index(['1', '2', '3'])
>>> idx._internal_get_values()
array(['1', '2', '3'], dtype=object)
`MultiIndex` arrays also have only one dimension:
>>> midx = pd.MultiIndex.from_arrays([[1, 2, 3], ['a', 'b', 'c']],
... names=('number', 'letter'))
>>> midx._internal_get_values()
array([(1, 'a'), (2, 'b'), (3, 'c')], dtype=object)
>>> midx._internal_get_values().ndim
1
"""
return self.values
@Appender(IndexOpsMixin.memory_usage.__doc__)
def memory_usage(self, deep: bool = False) -> int:
result = super().memory_usage(deep=deep)
# include our engine hashtable
result += self._engine.sizeof(deep=deep)
return result
def where(self, cond, other=None):
"""
Return an Index of same shape as self and whose corresponding
entries are from self where cond is True and otherwise are from
other.
Parameters
----------
cond : bool array-like with the same length as self
other : scalar, or array-like
Returns
-------
Index
"""
if other is None:
other = self._na_value
dtype = self.dtype
values = self.values
if is_bool(other) or is_bool_dtype(other):
# bools force casting
values = values.astype(object)
dtype = None
values = np.where(cond, values, other)
if self._is_numeric_dtype and np.any(isna(values)):
# We can't coerce to the numeric dtype of "self" (unless
# it's float) if there are NaN values in our output.
dtype = None
return self._shallow_copy_with_infer(values, dtype=dtype)
# construction helpers
@classmethod
def _scalar_data_error(cls, data):
# We return the TypeError so that we can raise it from the constructor
# in order to keep mypy happy
return TypeError(
f"{cls.__name__}(...) must be called with a collection of some "
f"kind, {repr(data)} was passed"
)
@classmethod
def _string_data_error(cls, data):
raise TypeError(
"String dtype not supported, you may need "
"to explicitly cast to a numeric type"
)
def _coerce_scalar_to_index(self, item):
"""
We need to coerce a scalar to a compat for our index type.
Parameters
----------
item : scalar item to coerce
"""
dtype = self.dtype
if self._is_numeric_dtype and isna(item):
# We can't coerce to the numeric dtype of "self" (unless
# it's float) if there are NaN values in our output.
dtype = None
return Index([item], dtype=dtype, **self._get_attributes_dict())
def _to_safe_for_reshape(self):
"""
Convert to object if we are a categorical.
"""
return self
def _convert_for_op(self, value):
"""
Convert value to be insertable to ndarray.
"""
return value
def _assert_can_do_op(self, value):
"""
Check value is valid for scalar op.
"""
if not is_scalar(value):
raise TypeError(f"'value' must be a scalar, passed: {type(value).__name__}")
@property
def _has_complex_internals(self) -> bool:
"""
Indicates if an index is not directly backed by a numpy array
"""
# used to avoid libreduction code paths, which raise or require conversion
return False
def _is_memory_usage_qualified(self) -> bool:
"""
Return a boolean if we need a qualified .info display.
"""
return self.is_object()
def is_type_compatible(self, kind) -> bool:
"""
Whether the index type is compatible with the provided type.
"""
return kind == self.inferred_type
def __contains__(self, key: Any) -> bool:
"""
Return a boolean indicating whether the provided key is in the index.
Parameters
----------
key : label
The key to check if it is present in the index.
Returns
-------
bool
Whether the key search is in the index.
Raises
------
TypeError
If the key is not hashable.
See Also
--------
Index.isin : Returns an ndarray of boolean dtype indicating whether the
list-like key is in the index.
Examples
--------
>>> idx = pd.Index([1, 2, 3, 4])
>>> idx
Int64Index([1, 2, 3, 4], dtype='int64')
>>> 2 in idx
True
>>> 6 in idx
False
"""
hash(key)
try:
return key in self._engine
except (OverflowError, TypeError, ValueError):
return False
def __hash__(self):
raise TypeError(f"unhashable type: {repr(type(self).__name__)}")
def __setitem__(self, key, value):
raise TypeError("Index does not support mutable operations")
def __getitem__(self, key):
"""
Override numpy.ndarray's __getitem__ method to work as desired.
This function adds lists and Series as valid boolean indexers
(ndarrays only supports ndarray with dtype=bool).
If resulting ndim != 1, plain ndarray is returned instead of
corresponding `Index` subclass.
"""
# There's no custom logic to be implemented in __getslice__, so it's
# not overloaded intentionally.
getitem = self._data.__getitem__
promote = self._shallow_copy
if is_scalar(key):
key = com.cast_scalar_indexer(key)
return getitem(key)
if isinstance(key, slice):
# This case is separated from the conditional above to avoid
# pessimization of basic indexing.
return promote(getitem(key))
if com.is_bool_indexer(key):
key = np.asarray(key, dtype=bool)
key = com.values_from_object(key)
result = getitem(key)
if not is_scalar(result):
if np.ndim(result) > 1:
deprecate_ndim_indexing(result)
return result
return promote(result)
else:
return result
def _can_hold_identifiers_and_holds_name(self, name) -> bool:
"""
Faster check for ``name in self`` when we know `name` is a Python
identifier (e.g. in NDFrame.__getattr__, which hits this to support
. key lookup). For indexes that can't hold identifiers (everything
but object & categorical) we just return False.
https://github.com/pandas-dev/pandas/issues/19764
"""
if self.is_object() or self.is_categorical():
return name in self
return False
def append(self, other):
"""
Append a collection of Index options together.
Parameters
----------
other : Index or list/tuple of indices
Returns
-------
appended : Index
"""
to_concat = [self]
if isinstance(other, (list, tuple)):
to_concat = to_concat + list(other)
else:
to_concat.append(other)
for obj in to_concat:
if not isinstance(obj, Index):
raise TypeError("all inputs must be Index")
names = {obj.name for obj in to_concat}
name = None if len(names) > 1 else self.name
return self._concat(to_concat, name)
def _concat(self, to_concat, name):
typs = _concat.get_dtype_kinds(to_concat)
if len(typs) == 1:
return self._concat_same_dtype(to_concat, name=name)
return Index._concat_same_dtype(self, to_concat, name=name)
def _concat_same_dtype(self, to_concat, name):
"""
Concatenate to_concat which has the same class.
"""
# must be overridden in specific classes
klasses = (
ABCDatetimeIndex,
ABCTimedeltaIndex,
ABCPeriodIndex,
ExtensionArray,
ABCIntervalIndex,
)
to_concat = [
x.astype(object) if isinstance(x, klasses) else x for x in to_concat
]
self = to_concat[0]
attribs = self._get_attributes_dict()
attribs["name"] = name
to_concat = [x._values if isinstance(x, Index) else x for x in to_concat]
return self._shallow_copy_with_infer(np.concatenate(to_concat), **attribs)
def putmask(self, mask, value):
"""
Return a new Index of the values set with the mask.
Returns
-------
Index
See Also
--------
numpy.ndarray.putmask
"""
values = self.values.copy()
try:
np.putmask(values, mask, self._convert_for_op(value))
return self._shallow_copy(values)
except (ValueError, TypeError) as err:
if is_object_dtype(self):
raise err
# coerces to object
return self.astype(object).putmask(mask, value)
def equals(self, other) -> bool:
"""
Determine if two Index objects contain the same elements.
Returns
-------
bool
True if "other" is an Index and it has the same elements as calling
index; False otherwise.
"""
if self.is_(other):
return True
if not isinstance(other, Index):
return False
if is_object_dtype(self) and not is_object_dtype(other):
# if other is not object, use other's logic for coercion
return other.equals(self)
if isinstance(other, ABCMultiIndex):
# d-level MultiIndex can equal d-tuple Index
if not is_object_dtype(self.dtype):
if self.nlevels != other.nlevels:
return False
return array_equivalent(
com.values_from_object(self), com.values_from_object(other)
)
def identical(self, other) -> bool:
"""
Similar to equals, but check that other comparable attributes are
also equal.
Returns
-------
bool
If two Index objects have equal elements and same type True,
otherwise False.
"""
return (
self.equals(other)
and all(
(
getattr(self, c, None) == getattr(other, c, None)
for c in self._comparables
)
)
and type(self) == type(other)
)
def asof(self, label):
"""
Return the label from the index, or, if not present, the previous one.
Assuming that the index is sorted, return the passed index label if it
is in the index, or return the previous index label if the passed one
is not in the index.
Parameters
----------
label : object
The label up to which the method returns the latest index label.
Returns
-------
object
The passed label if it is in the index. The previous label if the
passed label is not in the sorted index or `NaN` if there is no
such label.
See Also
--------
Series.asof : Return the latest value in a Series up to the
passed index.
merge_asof : Perform an asof merge (similar to left join but it
matches on nearest key rather than equal key).
Index.get_loc : An `asof` is a thin wrapper around `get_loc`
with method='pad'.
Examples
--------
`Index.asof` returns the latest index label up to the passed label.
>>> idx = pd.Index(['2013-12-31', '2014-01-02', '2014-01-03'])
>>> idx.asof('2014-01-01')
'2013-12-31'
If the label is in the index, the method returns the passed label.
>>> idx.asof('2014-01-02')
'2014-01-02'
If all of the labels in the index are later than the passed label,
NaN is returned.
>>> idx.asof('1999-01-02')
nan
If the index is not sorted, an error is raised.
>>> idx_not_sorted = pd.Index(['2013-12-31', '2015-01-02',
... '2014-01-03'])
>>> idx_not_sorted.asof('2013-12-31')
Traceback (most recent call last):
ValueError: index must be monotonic increasing or decreasing
"""
try:
loc = self.get_loc(label, method="pad")
except KeyError:
return self._na_value
else:
if isinstance(loc, slice):
loc = loc.indices(len(self))[-1]
return self[loc]
def asof_locs(self, where, mask):
"""
Find the locations (indices) of the labels from the index for
every entry in the `where` argument.
As in the `asof` function, if the label (a particular entry in
`where`) is not in the index, the latest index label up to the
passed label is chosen and its index returned.
If all of the labels in the index are later than a label in `where`,
-1 is returned.
`mask` is used to ignore NA values in the index during calculation.
Parameters
----------
where : Index
An Index consisting of an array of timestamps.
mask : array-like
Array of booleans denoting where values in the original
data are not NA.
Returns
-------
numpy.ndarray
An array of locations (indices) of the labels from the Index
which correspond to the return values of the `asof` function
for every element in `where`.
"""
locs = self.values[mask].searchsorted(where.values, side="right")
locs = np.where(locs > 0, locs - 1, 0)
result = np.arange(len(self))[mask].take(locs)
first = mask.argmax()
result[(locs == 0) & (where.values < self.values[first])] = -1
return result
def sort_values(self, return_indexer: bool = False, ascending: bool = True):
"""
Return a sorted copy of the index.
Return a sorted copy of the index, and optionally return the indices
that sorted the index itself.
Parameters
----------
return_indexer : bool, default False
Should the indices that would sort the index be returned.
ascending : bool, default True
Should the index values be sorted in an ascending order.
Returns
-------
sorted_index : pandas.Index
Sorted copy of the index.
indexer : numpy.ndarray, optional
The indices that the index itself was sorted by.
See Also
--------
Series.sort_values : Sort values of a Series.
DataFrame.sort_values : Sort values in a DataFrame.
Examples
--------
>>> idx = pd.Index([10, 100, 1, 1000])
>>> idx
Int64Index([10, 100, 1, 1000], dtype='int64')
Sort values in ascending order (default behavior).
>>> idx.sort_values()
Int64Index([1, 10, 100, 1000], dtype='int64')
Sort values in descending order, and also get the indices `idx` was
sorted by.
>>> idx.sort_values(ascending=False, return_indexer=True)
(Int64Index([1000, 100, 10, 1], dtype='int64'), array([3, 1, 0, 2]))
"""
_as = self.argsort()
if not ascending:
_as = _as[::-1]
sorted_index = self.take(_as)
if return_indexer:
return sorted_index, _as
else:
return sorted_index
def sort(self, *args, **kwargs):
"""
Use sort_values instead.
"""
raise TypeError("cannot sort an Index object in-place, use sort_values instead")
def shift(self, periods=1, freq=None):
"""
Shift index by desired number of time frequency increments.
This method is for shifting the values of datetime-like indexes
by a specified time increment a given number of times.
Parameters
----------
periods : int, default 1
Number of periods (or increments) to shift by,
can be positive or negative.
freq : pandas.DateOffset, pandas.Timedelta or str, optional
Frequency increment to shift by.
If None, the index is shifted by its own `freq` attribute.
Offset aliases are valid strings, e.g., 'D', 'W', 'M' etc.
Returns
-------
pandas.Index
Shifted index.
See Also
--------
Series.shift : Shift values of Series.
Notes
-----
This method is only implemented for datetime-like index classes,
i.e., DatetimeIndex, PeriodIndex and TimedeltaIndex.
Examples
--------
Put the first 5 month starts of 2011 into an index.
>>> month_starts = pd.date_range('1/1/2011', periods=5, freq='MS')
>>> month_starts
DatetimeIndex(['2011-01-01', '2011-02-01', '2011-03-01', '2011-04-01',
'2011-05-01'],
dtype='datetime64[ns]', freq='MS')
Shift the index by 10 days.
>>> month_starts.shift(10, freq='D')
DatetimeIndex(['2011-01-11', '2011-02-11', '2011-03-11', '2011-04-11',
'2011-05-11'],
dtype='datetime64[ns]', freq=None)
The default value of `freq` is the `freq` attribute of the index,
which is 'MS' (month start) in this example.
>>> month_starts.shift(10)
DatetimeIndex(['2011-11-01', '2011-12-01', '2012-01-01', '2012-02-01',
'2012-03-01'],
dtype='datetime64[ns]', freq='MS')
"""
raise NotImplementedError(f"Not supported for type {type(self).__name__}")
def argsort(self, *args, **kwargs) -> np.ndarray:
"""
Return the integer indices that would sort the index.
Parameters
----------
*args
Passed to `numpy.ndarray.argsort`.
**kwargs
Passed to `numpy.ndarray.argsort`.
Returns
-------
numpy.ndarray
Integer indices that would sort the index if used as
an indexer.
See Also
--------
numpy.argsort : Similar method for NumPy arrays.
Index.sort_values : Return sorted copy of Index.
Examples
--------
>>> idx = pd.Index(['b', 'a', 'd', 'c'])
>>> idx
Index(['b', 'a', 'd', 'c'], dtype='object')
>>> order = idx.argsort()
>>> order
array([1, 0, 3, 2])
>>> idx[order]
Index(['a', 'b', 'c', 'd'], dtype='object')
"""
result = self.asi8
if result is None:
result = np.array(self)
return result.argsort(*args, **kwargs)
def get_value(self, series: "Series", key):
"""
Fast lookup of value from 1-dimensional ndarray. Only use this if you
know what you're doing.
Returns
-------
scalar or Series
"""
if not is_scalar(key):
# if key is not a scalar, directly raise an error (the code below
# would convert to numpy arrays and raise later any way) - GH29926
raise InvalidIndexError(key)
try:
# GH 20882, 21257
# First try to convert the key to a location
# If that fails, raise a KeyError if an integer
# index, otherwise, see if key is an integer, and
# try that
loc = self.get_loc(key)
except KeyError:
if not self._should_fallback_to_positional():
raise
elif is_integer(key):
# If the Index cannot hold integer, then this is unambiguously
# a locational lookup.
loc = key
else:
raise
return self._get_values_for_loc(series, loc, key)
def _should_fallback_to_positional(self) -> bool:
"""
If an integer key is not found, should we fall back to positional indexing?
"""
if len(self) > 0 and (self.holds_integer() or self.is_boolean()):
return False
return True
def _get_values_for_loc(self, series: "Series", loc, key):
"""
Do a positional lookup on the given Series, returning either a scalar
or a Series.
Assumes that `series.index is self`
key is included for MultiIndex compat.
"""
if is_integer(loc):
return series._values[loc]
return series.iloc[loc]
def set_value(self, arr, key, value):
"""
Fast lookup of value from 1-dimensional ndarray.
.. deprecated:: 1.0
Notes
-----
Only use this if you know what you're doing.
"""
warnings.warn(
(
"The 'set_value' method is deprecated, and "
"will be removed in a future version."
),
FutureWarning,
stacklevel=2,
)
loc = self._engine.get_loc(key)
validate_numeric_casting(arr.dtype, value)
arr[loc] = value
_index_shared_docs[
"get_indexer_non_unique"
] = """
Compute indexer and mask for new index given the current index. The
indexer should be then used as an input to ndarray.take to align the
current data to the new index.
Parameters
----------
target : %(target_klass)s
Returns
-------
indexer : ndarray of int
Integers from 0 to n - 1 indicating that the index at these
positions matches the corresponding target values. Missing values
in the target are marked by -1.
missing : ndarray of int
An indexer into the target of the values not found.
These correspond to the -1 in the indexer array.
"""
@Appender(_index_shared_docs["get_indexer_non_unique"] % _index_doc_kwargs)
def get_indexer_non_unique(self, target):
target = ensure_index(target)
pself, ptarget = self._maybe_promote(target)
if pself is not self or ptarget is not target:
return pself.get_indexer_non_unique(ptarget)
if is_categorical(target):
tgt_values = np.asarray(target)
elif self.is_all_dates and target.is_all_dates: # GH 30399
tgt_values = target.asi8
else:
tgt_values = target._ndarray_values
indexer, missing = self._engine.get_indexer_non_unique(tgt_values)
return ensure_platform_int(indexer), missing
def get_indexer_for(self, target, **kwargs):
"""
Guaranteed return of an indexer even when non-unique.
This dispatches to get_indexer or get_indexer_non_unique
as appropriate.
Returns
-------
numpy.ndarray
List of indices.
"""
if self.is_unique:
return self.get_indexer(target, **kwargs)
indexer, _ = self.get_indexer_non_unique(target, **kwargs)
return indexer
def _maybe_promote(self, other):
# A hack, but it works
if self.inferred_type == "date" and isinstance(other, ABCDatetimeIndex):
return type(other)(self), other
elif self.inferred_type == "boolean":
if not is_object_dtype(self.dtype):
return self.astype("object"), other.astype("object")
return self, other
def groupby(self, values) -> PrettyDict[Hashable, np.ndarray]:
"""
Group the index labels by a given array of values.
Parameters
----------
values : array
Values used to determine the groups.
Returns
-------
dict
{group name -> group labels}
"""
# TODO: if we are a MultiIndex, we can do better
# that converting to tuples
if isinstance(values, ABCMultiIndex):
values = values.values
values = ensure_categorical(values)
result = values._reverse_indexer()
# map to the label
result = {k: self.take(v) for k, v in result.items()}
return PrettyDict(result)
def map(self, mapper, na_action=None):
"""
Map values using input correspondence (a dict, Series, or function).
Parameters
----------
mapper : function, dict, or Series
Mapping correspondence.
na_action : {None, 'ignore'}
If 'ignore', propagate NA values, without passing them to the
mapping correspondence.
Returns
-------
applied : Union[Index, MultiIndex], inferred
The output of the mapping function applied to the index.
If the function returns a tuple with more than one element
a MultiIndex will be returned.
"""
from pandas.core.indexes.multi import MultiIndex
new_values = super()._map_values(mapper, na_action=na_action)
attributes = self._get_attributes_dict()
# we can return a MultiIndex
if new_values.size and isinstance(new_values[0], tuple):
if isinstance(self, MultiIndex):
names = self.names
elif attributes.get("name"):
names = [attributes.get("name")] * len(new_values[0])
else:
names = None
return MultiIndex.from_tuples(new_values, names=names)
attributes["copy"] = False
if not new_values.size:
# empty
attributes["dtype"] = self.dtype
return Index(new_values, **attributes)
def isin(self, values, level=None):
"""
Return a boolean array where the index values are in `values`.
Compute boolean array of whether each index value is found in the
passed set of values. The length of the returned boolean array matches
the length of the index.
Parameters
----------
values : set or list-like
Sought values.
level : str or int, optional
Name or position of the index level to use (if the index is a
`MultiIndex`).
Returns
-------
is_contained : ndarray
NumPy array of boolean values.
See Also
--------
Series.isin : Same for Series.
DataFrame.isin : Same method for DataFrames.
Notes
-----
In the case of `MultiIndex` you must either specify `values` as a
list-like object containing tuples that are the same length as the
number of levels, or specify `level`. Otherwise it will raise a
``ValueError``.
If `level` is specified:
- if it is the name of one *and only one* index level, use that level;
- otherwise it should be a number indicating level position.
Examples
--------
>>> idx = pd.Index([1,2,3])
>>> idx
Int64Index([1, 2, 3], dtype='int64')
Check whether each index value in a list of values.
>>> idx.isin([1, 4])
array([ True, False, False])
>>> midx = pd.MultiIndex.from_arrays([[1,2,3],
... ['red', 'blue', 'green']],
... names=('number', 'color'))
>>> midx
MultiIndex(levels=[[1, 2, 3], ['blue', 'green', 'red']],
codes=[[0, 1, 2], [2, 0, 1]],
names=['number', 'color'])
Check whether the strings in the 'color' level of the MultiIndex
are in a list of colors.
>>> midx.isin(['red', 'orange', 'yellow'], level='color')
array([ True, False, False])
To check across the levels of a MultiIndex, pass a list of tuples:
>>> midx.isin([(1, 'red'), (3, 'red')])
array([ True, False, False])
For a DatetimeIndex, string values in `values` are converted to
Timestamps.
>>> dates = ['2000-03-11', '2000-03-12', '2000-03-13']
>>> dti = pd.to_datetime(dates)
>>> dti
DatetimeIndex(['2000-03-11', '2000-03-12', '2000-03-13'],
dtype='datetime64[ns]', freq=None)
>>> dti.isin(['2000-03-11'])
array([ True, False, False])
"""
if level is not None:
self._validate_index_level(level)
return algos.isin(self, values)
def _get_string_slice(self, key: str_t, use_lhs: bool = True, use_rhs: bool = True):
# this is for partial string indexing,
# overridden in DatetimeIndex, TimedeltaIndex and PeriodIndex
raise NotImplementedError
def slice_indexer(self, start=None, end=None, step=None, kind=None):
"""
For an ordered or unique index, compute the slice indexer for input
labels and step.
Parameters
----------
start : label, default None
If None, defaults to the beginning.
end : label, default None
If None, defaults to the end.
step : int, default None
kind : str, default None
Returns
-------
indexer : slice
Raises
------
KeyError : If key does not exist, or key is not unique and index is
not ordered.
Notes
-----
This function assumes that the data is sorted, so use at your own peril
Examples
--------
This is a method on all index types. For example you can do:
>>> idx = pd.Index(list('abcd'))
>>> idx.slice_indexer(start='b', end='c')
slice(1, 3)
>>> idx = pd.MultiIndex.from_arrays([list('abcd'), list('efgh')])
>>> idx.slice_indexer(start='b', end=('c', 'g'))
slice(1, 3)
"""
start_slice, end_slice = self.slice_locs(start, end, step=step, kind=kind)
# return a slice
if not is_scalar(start_slice):
raise AssertionError("Start slice bound is non-scalar")
if not is_scalar(end_slice):
raise AssertionError("End slice bound is non-scalar")
return slice(start_slice, end_slice, step)
def _maybe_cast_indexer(self, key):
"""
If we have a float key and are not a floating index, then try to cast
to an int if equivalent.
"""
if not self.is_floating():
return com.cast_scalar_indexer(key)
return key
def _validate_indexer(self, form: str_t, key, kind: str_t):
"""
If we are positional indexer, validate that we have appropriate
typed bounds must be an integer.
"""
assert kind in ["getitem", "iloc"]
if key is None:
pass
elif is_integer(key):
pass
else:
self._invalid_indexer(form, key)
def _maybe_cast_slice_bound(self, label, side: str_t, kind):
"""
This function should be overloaded in subclasses that allow non-trivial
casting on label-slice bounds, e.g. datetime-like indices allowing
strings containing formatted datetimes.
Parameters
----------
label : object
side : {'left', 'right'}
kind : {'loc', 'getitem'} or None
Returns
-------
label : object
Notes
-----
Value of `side` parameter should be validated in caller.
"""
assert kind in ["loc", "getitem", None]
# We are a plain index here (sub-class override this method if they
# wish to have special treatment for floats/ints, e.g. Float64Index and
# datetimelike Indexes
# reject them
if is_float(label):
self._invalid_indexer("slice", label)
# we are trying to find integer bounds on a non-integer based index
# this is rejected (generally .loc gets you here)
elif is_integer(label):
self._invalid_indexer("slice", label)
return label
def _searchsorted_monotonic(self, label, side="left"):
if self.is_monotonic_increasing:
return self.searchsorted(label, side=side)
elif self.is_monotonic_decreasing:
# np.searchsorted expects ascending sort order, have to reverse
# everything for it to work (element ordering, search side and
# resulting value).
pos = self[::-1].searchsorted(
label, side="right" if side == "left" else "left"
)
return len(self) - pos
raise ValueError("index must be monotonic increasing or decreasing")
def get_slice_bound(self, label, side: str_t, kind) -> int:
"""
Calculate slice bound that corresponds to given label.
Returns leftmost (one-past-the-rightmost if ``side=='right'``) position
of given label.
Parameters
----------
label : object
side : {'left', 'right'}
kind : {'loc', 'getitem'} or None
Returns
-------
int
Index of label.
"""
assert kind in ["loc", "getitem", None]
if side not in ("left", "right"):
raise ValueError(
"Invalid value for side kwarg, must be either "
f"'left' or 'right': {side}"
)
original_label = label
# For datetime indices label may be a string that has to be converted
# to datetime boundary according to its resolution.
label = self._maybe_cast_slice_bound(label, side, kind)
# we need to look up the label
try:
slc = self.get_loc(label)
except KeyError as err:
try:
return self._searchsorted_monotonic(label, side)
except ValueError:
# raise the original KeyError
raise err
if isinstance(slc, np.ndarray):
# get_loc may return a boolean array or an array of indices, which
# is OK as long as they are representable by a slice.
if is_bool_dtype(slc):
slc = lib.maybe_booleans_to_slice(slc.view("u1"))
else:
slc = lib.maybe_indices_to_slice(slc.astype("i8"), len(self))
if isinstance(slc, np.ndarray):
raise KeyError(
f"Cannot get {side} slice bound for non-unique "
f"label: {repr(original_label)}"
)
if isinstance(slc, slice):
if side == "left":
return slc.start
else:
return slc.stop
else:
if side == "right":
return slc + 1
else:
return slc
def slice_locs(self, start=None, end=None, step=None, kind=None):
"""
Compute slice locations for input labels.
Parameters
----------
start : label, default None
If None, defaults to the beginning.
end : label, default None
If None, defaults to the end.
step : int, defaults None
If None, defaults to 1.
kind : {'loc', 'getitem'} or None
Returns
-------
start, end : int
See Also
--------
Index.get_loc : Get location for a single label.
Notes
-----
This method only works if the index is monotonic or unique.
Examples
--------
>>> idx = pd.Index(list('abcd'))
>>> idx.slice_locs(start='b', end='c')
(1, 3)
"""
inc = step is None or step >= 0
if not inc:
# If it's a reverse slice, temporarily swap bounds.
start, end = end, start
# GH 16785: If start and end happen to be date strings with UTC offsets
# attempt to parse and check that the offsets are the same
if isinstance(start, (str, datetime)) and isinstance(end, (str, datetime)):
try:
ts_start = Timestamp(start)
ts_end = Timestamp(end)
except (ValueError, TypeError):
pass
else:
if not tz_compare(ts_start.tzinfo, ts_end.tzinfo):
raise ValueError("Both dates must have the same UTC offset")
start_slice = None
if start is not None:
start_slice = self.get_slice_bound(start, "left", kind)
if start_slice is None:
start_slice = 0
end_slice = None
if end is not None:
end_slice = self.get_slice_bound(end, "right", kind)
if end_slice is None:
end_slice = len(self)
if not inc:
# Bounds at this moment are swapped, swap them back and shift by 1.
#
# slice_locs('B', 'A', step=-1): s='B', e='A'
#
# s='A' e='B'
# AFTER SWAP: | |
# v ------------------> V
# -----------------------------------
# | | |A|A|A|A| | | | | |B|B| | | | |
# -----------------------------------
# ^ <------------------ ^
# SHOULD BE: | |
# end=s-1 start=e-1
#
end_slice, start_slice = start_slice - 1, end_slice - 1
# i == -1 triggers ``len(self) + i`` selection that points to the
# last element, not before-the-first one, subtracting len(self)
# compensates that.
if end_slice == -1:
end_slice -= len(self)
if start_slice == -1:
start_slice -= len(self)
return start_slice, end_slice
def delete(self, loc):
"""
Make new Index with passed location(-s) deleted.
Parameters
----------
loc : int or list of int
Location of item(-s) which will be deleted.
Use a list of locations to delete more than one value at the same time.
Returns
-------
Index
New Index with passed location(-s) deleted.
See Also
--------
numpy.delete : Delete any rows and column from NumPy array (ndarray).
Examples
--------
>>> idx = pd.Index(['a', 'b', 'c'])
>>> idx.delete(1)
Index(['a', 'c'], dtype='object')
>>> idx = pd.Index(['a', 'b', 'c'])
>>> idx.delete([0, 2])
Index(['b'], dtype='object')
"""
return self._shallow_copy(np.delete(self._data, loc))
def insert(self, loc: int, item):
"""
Make new Index inserting new item at location.
Follows Python list.append semantics for negative values.
Parameters
----------
loc : int
item : object
Returns
-------
new_index : Index
"""
_self = np.asarray(self)
item = self._coerce_scalar_to_index(item)._ndarray_values
idx = np.concatenate((_self[:loc], item, _self[loc:]))
return self._shallow_copy_with_infer(idx)
def drop(self, labels, errors: str_t = "raise"):
"""
Make new Index with passed list of labels deleted.
Parameters
----------
labels : array-like
errors : {'ignore', 'raise'}, default 'raise'
If 'ignore', suppress error and existing labels are dropped.
Returns
-------
dropped : Index
Raises
------
KeyError
If not all of the labels are found in the selected axis
"""
arr_dtype = "object" if self.dtype == "object" else None
labels = com.index_labels_to_array(labels, dtype=arr_dtype)
indexer = self.get_indexer(labels)
mask = indexer == -1
if mask.any():
if errors != "ignore":
raise KeyError(f"{labels[mask]} not found in axis")
indexer = indexer[~mask]
return self.delete(indexer)
# --------------------------------------------------------------------
# Generated Arithmetic, Comparison, and Unary Methods
@classmethod
def _add_comparison_methods(cls):
"""
Add in comparison methods.
"""
cls.__eq__ = _make_comparison_op(operator.eq, cls)
cls.__ne__ = _make_comparison_op(operator.ne, cls)
cls.__lt__ = _make_comparison_op(operator.lt, cls)
cls.__gt__ = _make_comparison_op(operator.gt, cls)
cls.__le__ = _make_comparison_op(operator.le, cls)
cls.__ge__ = _make_comparison_op(operator.ge, cls)
@classmethod
def _add_numeric_methods_add_sub_disabled(cls):
"""
Add in the numeric add/sub methods to disable.
"""
cls.__add__ = make_invalid_op("__add__")
cls.__radd__ = make_invalid_op("__radd__")
cls.__iadd__ = make_invalid_op("__iadd__")
cls.__sub__ = make_invalid_op("__sub__")
cls.__rsub__ = make_invalid_op("__rsub__")
cls.__isub__ = make_invalid_op("__isub__")
@classmethod
def _add_numeric_methods_disabled(cls):
"""
Add in numeric methods to disable other than add/sub.
"""
cls.__pow__ = make_invalid_op("__pow__")
cls.__rpow__ = make_invalid_op("__rpow__")
cls.__mul__ = make_invalid_op("__mul__")
cls.__rmul__ = make_invalid_op("__rmul__")
cls.__floordiv__ = make_invalid_op("__floordiv__")
cls.__rfloordiv__ = make_invalid_op("__rfloordiv__")
cls.__truediv__ = make_invalid_op("__truediv__")
cls.__rtruediv__ = make_invalid_op("__rtruediv__")
cls.__mod__ = make_invalid_op("__mod__")
cls.__divmod__ = make_invalid_op("__divmod__")
cls.__neg__ = make_invalid_op("__neg__")
cls.__pos__ = make_invalid_op("__pos__")
cls.__abs__ = make_invalid_op("__abs__")
cls.__inv__ = make_invalid_op("__inv__")
@classmethod
def _add_numeric_methods_binary(cls):
"""
Add in numeric methods.
"""
cls.__add__ = _make_arithmetic_op(operator.add, cls)
cls.__radd__ = _make_arithmetic_op(ops.radd, cls)
cls.__sub__ = _make_arithmetic_op(operator.sub, cls)
cls.__rsub__ = _make_arithmetic_op(ops.rsub, cls)
cls.__rpow__ = _make_arithmetic_op(ops.rpow, cls)
cls.__pow__ = _make_arithmetic_op(operator.pow, cls)
cls.__truediv__ = _make_arithmetic_op(operator.truediv, cls)
cls.__rtruediv__ = _make_arithmetic_op(ops.rtruediv, cls)
# TODO: rmod? rdivmod?
cls.__mod__ = _make_arithmetic_op(operator.mod, cls)
cls.__floordiv__ = _make_arithmetic_op(operator.floordiv, cls)
cls.__rfloordiv__ = _make_arithmetic_op(ops.rfloordiv, cls)
cls.__divmod__ = _make_arithmetic_op(divmod, cls)
cls.__mul__ = _make_arithmetic_op(operator.mul, cls)
cls.__rmul__ = _make_arithmetic_op(ops.rmul, cls)
@classmethod
def _add_numeric_methods_unary(cls):
"""
Add in numeric unary methods.
"""
def _make_evaluate_unary(op, opstr):
def _evaluate_numeric_unary(self):
attrs = self._get_attributes_dict()
return Index(op(self.values), **attrs)
_evaluate_numeric_unary.__name__ = opstr
return _evaluate_numeric_unary
cls.__neg__ = _make_evaluate_unary(operator.neg, "__neg__")
cls.__pos__ = _make_evaluate_unary(operator.pos, "__pos__")
cls.__abs__ = _make_evaluate_unary(np.abs, "__abs__")
cls.__inv__ = _make_evaluate_unary(lambda x: -x, "__inv__")
@classmethod
def _add_numeric_methods(cls):
cls._add_numeric_methods_unary()
cls._add_numeric_methods_binary()
@classmethod
def _add_logical_methods(cls):
"""
Add in logical methods.
"""
_doc = """
%(desc)s
Parameters
----------
*args
These parameters will be passed to numpy.%(outname)s.
**kwargs
These parameters will be passed to numpy.%(outname)s.
Returns
-------
%(outname)s : bool or array_like (if axis is specified)
A single element array_like may be converted to bool."""
_index_shared_docs["index_all"] = dedent(
"""
See Also
--------
Index.any : Return whether any element in an Index is True.
Series.any : Return whether any element in a Series is True.
Series.all : Return whether all elements in a Series are True.
Notes
-----
Not a Number (NaN), positive infinity and negative infinity
evaluate to True because these are not equal to zero.
Examples
--------
**all**
True, because nonzero integers are considered True.
>>> pd.Index([1, 2, 3]).all()
True
False, because ``0`` is considered False.
>>> pd.Index([0, 1, 2]).all()
False
**any**
True, because ``1`` is considered True.
>>> pd.Index([0, 0, 1]).any()
True
False, because ``0`` is considered False.
>>> pd.Index([0, 0, 0]).any()
False
"""
)
_index_shared_docs["index_any"] = dedent(
"""
See Also
--------
Index.all : Return whether all elements are True.
Series.all : Return whether all elements are True.
Notes
-----
Not a Number (NaN), positive infinity and negative infinity
evaluate to True because these are not equal to zero.
Examples
--------
>>> index = pd.Index([0, 1, 2])
>>> index.any()
True
>>> index = pd.Index([0, 0, 0])
>>> index.any()
False
"""
)
def _make_logical_function(name, desc, f):
@Substitution(outname=name, desc=desc)
@Appender(_index_shared_docs["index_" + name])
@Appender(_doc)
def logical_func(self, *args, **kwargs):
result = f(self.values)
if (
isinstance(result, (np.ndarray, ABCSeries, Index))
and result.ndim == 0
):
# return NumPy type
return result.dtype.type(result.item())
else: # pragma: no cover
return result
logical_func.__name__ = name
return logical_func
cls.all = _make_logical_function(
"all", "Return whether all elements are True.", np.all
)
cls.any = _make_logical_function(
"any", "Return whether any element is True.", np.any
)
@classmethod
def _add_logical_methods_disabled(cls):
"""
Add in logical methods to disable.
"""
cls.all = make_invalid_op("all")
cls.any = make_invalid_op("any")
@property
def shape(self):
"""
Return a tuple of the shape of the underlying data.
"""
# not using "(len(self), )" to return "correct" shape if the values
# consists of a >1 D array (see GH-27775)
# overridden in MultiIndex.shape to avoid materializing the values
return self._values.shape
Index._add_numeric_methods_disabled()
Index._add_logical_methods()
Index._add_comparison_methods()
def ensure_index_from_sequences(sequences, names=None):
"""
Construct an index from sequences of data.
A single sequence returns an Index. Many sequences returns a
MultiIndex.
Parameters
----------
sequences : sequence of sequences
names : sequence of str
Returns
-------
index : Index or MultiIndex
Examples
--------
>>> ensure_index_from_sequences([[1, 2, 3]], names=['name'])
Int64Index([1, 2, 3], dtype='int64', name='name')
>>> ensure_index_from_sequences([['a', 'a'], ['a', 'b']],
names=['L1', 'L2'])
MultiIndex([('a', 'a'),
('a', 'b')],
names=['L1', 'L2'])
See Also
--------
ensure_index
"""
from pandas.core.indexes.multi import MultiIndex
if len(sequences) == 1:
if names is not None:
names = names[0]
return Index(sequences[0], name=names)
else:
return MultiIndex.from_arrays(sequences, names=names)
def ensure_index(index_like, copy=False):
"""
Ensure that we have an index from some index-like object.
Parameters
----------
index : sequence
An Index or other sequence
copy : bool
Returns
-------
index : Index or MultiIndex
Examples
--------
>>> ensure_index(['a', 'b'])
Index(['a', 'b'], dtype='object')
>>> ensure_index([('a', 'a'), ('b', 'c')])
Index([('a', 'a'), ('b', 'c')], dtype='object')
>>> ensure_index([['a', 'a'], ['b', 'c']])
MultiIndex([('a', 'b'),
('a', 'c')],
dtype='object')
)
See Also
--------
ensure_index_from_sequences
"""
if isinstance(index_like, Index):
if copy:
index_like = index_like.copy()
return index_like
if hasattr(index_like, "name"):
return Index(index_like, name=index_like.name, copy=copy)
if is_iterator(index_like):
index_like = list(index_like)
# must check for exactly list here because of strict type
# check in clean_index_list
if isinstance(index_like, list):
if type(index_like) != list:
index_like = list(index_like)
converted, all_arrays = lib.clean_index_list(index_like)
if len(converted) > 0 and all_arrays:
from pandas.core.indexes.multi import MultiIndex
return MultiIndex.from_arrays(converted)
else:
index_like = converted
else:
# clean_index_list does the equivalent of copying
# so only need to do this if not list instance
if copy:
from copy import copy
index_like = copy(index_like)
return Index(index_like)
def _ensure_has_len(seq):
"""
If seq is an iterator, put its values into a list.
"""
try:
len(seq)
except TypeError:
return list(seq)
else:
return seq
def _trim_front(strings):
"""
Trims zeros and decimal points.
"""
trimmed = strings
while len(strings) > 0 and all(x[0] == " " for x in trimmed):
trimmed = [x[1:] for x in trimmed]
return trimmed
def _validate_join_method(method):
if method not in ["left", "right", "inner", "outer"]:
raise ValueError(f"do not recognize join method {method}")
def default_index(n):
from pandas.core.indexes.range import RangeIndex
return RangeIndex(0, n, name=None)
def maybe_extract_name(name, obj, cls) -> Optional[Hashable]:
"""
If no name is passed, then extract it from data, validating hashability.
"""
if name is None and isinstance(obj, (Index, ABCSeries)):
# Note we don't just check for "name" attribute since that would
# pick up e.g. dtype.name
name = obj.name
# GH#29069
if not is_hashable(name):
raise TypeError(f"{cls.__name__}.name must be a hashable type")
return name
def _maybe_cast_with_dtype(data: np.ndarray, dtype: np.dtype, copy: bool) -> np.ndarray:
"""
If a dtype is passed, cast to the closest matching dtype that is supported
by Index.
Parameters
----------
data : np.ndarray
dtype : np.dtype
copy : bool
Returns
-------
np.ndarray
"""
# we need to avoid having numpy coerce
# things that look like ints/floats to ints unless
# they are actually ints, e.g. '0' and 0.0
# should not be coerced
# GH 11836
if is_integer_dtype(dtype):
inferred = lib.infer_dtype(data, skipna=False)
if inferred == "integer":
data = maybe_cast_to_integer_array(data, dtype, copy=copy)
elif inferred in ["floating", "mixed-integer-float"]:
if isna(data).any():
raise ValueError("cannot convert float NaN to integer")
if inferred == "mixed-integer-float":
data = maybe_cast_to_integer_array(data, dtype)
# If we are actually all equal to integers,
# then coerce to integer.
try:
data = _try_convert_to_int_array(data, copy, dtype)
except ValueError:
data = np.array(data, dtype=np.float64, copy=copy)
elif inferred == "string":
pass
else:
data = data.astype(dtype)
elif is_float_dtype(dtype):
inferred = lib.infer_dtype(data, skipna=False)
if inferred == "string":
pass
else:
data = data.astype(dtype)
else:
data = np.array(data, dtype=dtype, copy=copy)
return data
def _maybe_cast_data_without_dtype(subarr):
"""
If we have an arraylike input but no passed dtype, try to infer
a supported dtype.
Parameters
----------
subarr : np.ndarray, Index, or Series
Returns
-------
converted : np.ndarray or ExtensionArray
dtype : np.dtype or ExtensionDtype
"""
# Runtime import needed bc IntervalArray imports Index
from pandas.core.arrays import (
IntervalArray,
PeriodArray,
DatetimeArray,
TimedeltaArray,
)
inferred = lib.infer_dtype(subarr, skipna=False)
if inferred == "integer":
try:
data = _try_convert_to_int_array(subarr, False, None)
return data, data.dtype
except ValueError:
pass
return subarr, object
elif inferred in ["floating", "mixed-integer-float", "integer-na"]:
# TODO: Returns IntegerArray for integer-na case in the future
return subarr, np.float64
elif inferred == "interval":
try:
data = IntervalArray._from_sequence(subarr, copy=False)
return data, data.dtype
except ValueError:
# GH27172: mixed closed Intervals --> object dtype
pass
elif inferred == "boolean":
# don't support boolean explicitly ATM
pass
elif inferred != "string":
if inferred.startswith("datetime"):
try:
data = DatetimeArray._from_sequence(subarr, copy=False)
return data, data.dtype
except (ValueError, OutOfBoundsDatetime):
# GH 27011
# If we have mixed timezones, just send it
# down the base constructor
pass
elif inferred.startswith("timedelta"):
data = TimedeltaArray._from_sequence(subarr, copy=False)
return data, data.dtype
elif inferred == "period":
try:
data = PeriodArray._from_sequence(subarr)
return data, data.dtype
except IncompatibleFrequency:
pass
return subarr, subarr.dtype
def _try_convert_to_int_array(
data: np.ndarray, copy: bool, dtype: np.dtype
) -> np.ndarray:
"""
Attempt to convert an array of data into an integer array.
Parameters
----------
data : The data to convert.
copy : bool
Whether to copy the data or not.
dtype : np.dtype
Returns
-------
int_array : data converted to either an ndarray[int64] or ndarray[uint64]
Raises
------
ValueError if the conversion was not successful.
"""
if not is_unsigned_integer_dtype(dtype):
# skip int64 conversion attempt if uint-like dtype is passed, as
# this could return Int64Index when UInt64Index is what's desired
try:
res = data.astype("i8", copy=False)
if (res == data).all():
return res # TODO: might still need to copy
except (OverflowError, TypeError, ValueError):
pass
# Conversion to int64 failed (possibly due to overflow) or was skipped,
# so let's try now with uint64.
try:
res = data.astype("u8", copy=False)
if (res == data).all():
return res # TODO: might still need to copy
except (OverflowError, TypeError, ValueError):
pass
raise ValueError
def _maybe_asobject(dtype, klass, data, copy: bool, name: Label, **kwargs):
"""
If an object dtype was specified, create the non-object Index
and then convert it to object.
Parameters
----------
dtype : np.dtype, ExtensionDtype, str
klass : Index subclass
data : list-like
copy : bool
name : hashable
**kwargs
Returns
-------
Index
Notes
-----
We assume that calling .astype(object) on this klass will make a copy.
"""
# GH#23524 passing `dtype=object` to DatetimeIndex is invalid,
# will raise in the where `data` is already tz-aware. So
# we leave it out of this step and cast to object-dtype after
# the DatetimeIndex construction.
if is_dtype_equal(_o_dtype, dtype):
# Note we can pass copy=False because the .astype below
# will always make a copy
index = klass(data, copy=False, name=name, **kwargs)
return index.astype(object)
return klass(data, dtype=dtype, copy=copy, name=name, **kwargs)
| BugsInPy/BugsInPy/temp/projects/pandas/bug-53-fixed/pandas/pandas/core/indexes/base.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-53-buggy/pandas/pandas/core/indexes/base.py |
pandas-bug-58 | import operator
from shutil import get_terminal_size
from typing import Dict, Hashable, List, Type, Union, cast
from warnings import warn
import numpy as np
from pandas._config import get_option
from pandas._libs import algos as libalgos, hashtable as htable
from pandas._typing import ArrayLike, Dtype, Ordered, Scalar
from pandas.compat.numpy import function as nv
from pandas.util._decorators import (
Appender,
Substitution,
cache_readonly,
deprecate_kwarg,
)
from pandas.util._validators import validate_bool_kwarg, validate_fillna_kwargs
from pandas.core.dtypes.cast import coerce_indexer_dtype, maybe_infer_to_datetimelike
from pandas.core.dtypes.common import (
ensure_int64,
ensure_object,
ensure_platform_int,
is_categorical_dtype,
is_datetime64_dtype,
is_dict_like,
is_dtype_equal,
is_extension_array_dtype,
is_integer_dtype,
is_iterator,
is_list_like,
is_object_dtype,
is_scalar,
is_sequence,
is_timedelta64_dtype,
needs_i8_conversion,
)
from pandas.core.dtypes.dtypes import CategoricalDtype
from pandas.core.dtypes.generic import ABCIndexClass, ABCSeries
from pandas.core.dtypes.inference import is_hashable
from pandas.core.dtypes.missing import isna, notna
from pandas.core import ops
from pandas.core.accessor import PandasDelegate, delegate_names
import pandas.core.algorithms as algorithms
from pandas.core.algorithms import _get_data_algo, factorize, take, take_1d, unique1d
from pandas.core.arrays.base import (
ExtensionArray,
_extension_array_shared_docs,
try_cast_to_ea,
)
from pandas.core.base import NoNewAttributesMixin, PandasObject, _shared_docs
import pandas.core.common as com
from pandas.core.construction import array, extract_array, sanitize_array
from pandas.core.indexers import check_array_indexer, deprecate_ndim_indexing
from pandas.core.missing import interpolate_2d
from pandas.core.ops.common import unpack_zerodim_and_defer
from pandas.core.sorting import nargsort
from pandas.io.formats import console
def _cat_compare_op(op):
opname = f"__{op.__name__}__"
@unpack_zerodim_and_defer(opname)
def func(self, other):
if is_list_like(other) and len(other) != len(self):
# TODO: Could this fail if the categories are listlike objects?
raise ValueError("Lengths must match.")
if not self.ordered:
if opname in ["__lt__", "__gt__", "__le__", "__ge__"]:
raise TypeError(
"Unordered Categoricals can only compare equality or not"
)
if isinstance(other, Categorical):
# Two Categoricals can only be be compared if the categories are
# the same (maybe up to ordering, depending on ordered)
msg = "Categoricals can only be compared if 'categories' are the same."
if len(self.categories) != len(other.categories):
raise TypeError(msg + " Categories are different lengths")
elif self.ordered and not (self.categories == other.categories).all():
raise TypeError(msg)
elif not set(self.categories) == set(other.categories):
raise TypeError(msg)
if not (self.ordered == other.ordered):
raise TypeError(
"Categoricals can only be compared if 'ordered' is the same"
)
if not self.ordered and not self.categories.equals(other.categories):
# both unordered and different order
other_codes = _get_codes_for_values(other, self.categories)
else:
other_codes = other._codes
f = getattr(self._codes, opname)
ret = f(other_codes)
mask = (self._codes == -1) | (other_codes == -1)
if mask.any():
# In other series, the leads to False, so do that here too
ret[mask] = False
return ret
if is_scalar(other):
if other in self.categories:
i = self.categories.get_loc(other)
ret = getattr(self._codes, opname)(i)
if opname not in {"__eq__", "__ge__", "__gt__"}:
# check for NaN needed if we are not equal or larger
mask = self._codes == -1
ret[mask] = False
return ret
else:
if opname == "__eq__":
return np.zeros(len(self), dtype=bool)
elif opname == "__ne__":
return np.ones(len(self), dtype=bool)
else:
raise TypeError(
f"Cannot compare a Categorical for op {opname} with a "
"scalar, which is not a category."
)
else:
# allow categorical vs object dtype array comparisons for equality
# these are only positional comparisons
if opname in ["__eq__", "__ne__"]:
return getattr(np.array(self), opname)(np.array(other))
raise TypeError(
f"Cannot compare a Categorical for op {opname} with "
f"type {type(other)}.\nIf you want to compare values, "
"use 'np.asarray(cat) <op> other'."
)
func.__name__ = opname
return func
def contains(cat, key, container):
"""
Helper for membership check for ``key`` in ``cat``.
This is a helper method for :method:`__contains__`
and :class:`CategoricalIndex.__contains__`.
Returns True if ``key`` is in ``cat.categories`` and the
location of ``key`` in ``categories`` is in ``container``.
Parameters
----------
cat : :class:`Categorical`or :class:`categoricalIndex`
key : a hashable object
The key to check membership for.
container : Container (e.g. list-like or mapping)
The container to check for membership in.
Returns
-------
is_in : bool
True if ``key`` is in ``self.categories`` and location of
``key`` in ``categories`` is in ``container``, else False.
Notes
-----
This method does not check for NaN values. Do that separately
before calling this method.
"""
hash(key)
# get location of key in categories.
# If a KeyError, the key isn't in categories, so logically
# can't be in container either.
try:
loc = cat.categories.get_loc(key)
except (KeyError, TypeError):
return False
# loc is the location of key in categories, but also the *value*
# for key in container. So, `key` may be in categories,
# but still not in `container`. Example ('b' in categories,
# but not in values):
# 'b' in Categorical(['a'], categories=['a', 'b']) # False
if is_scalar(loc):
return loc in container
else:
# if categories is an IntervalIndex, loc is an array.
return any(loc_ in container for loc_ in loc)
_codes_doc = """
The category codes of this categorical.
Level codes are an array if integer which are the positions of the real
values in the categories array.
There is not setter, use the other categorical methods and the normal item
setter to change values in the categorical.
"""
class Categorical(ExtensionArray, PandasObject):
"""
Represent a categorical variable in classic R / S-plus fashion.
`Categoricals` can only take on only a limited, and usually fixed, number
of possible values (`categories`). In contrast to statistical categorical
variables, a `Categorical` might have an order, but numerical operations
(additions, divisions, ...) are not possible.
All values of the `Categorical` are either in `categories` or `np.nan`.
Assigning values outside of `categories` will raise a `ValueError`. Order
is defined by the order of the `categories`, not lexical order of the
values.
Parameters
----------
values : list-like
The values of the categorical. If categories are given, values not in
categories will be replaced with NaN.
categories : Index-like (unique), optional
The unique categories for this categorical. If not given, the
categories are assumed to be the unique values of `values` (sorted, if
possible, otherwise in the order in which they appear).
ordered : bool, default False
Whether or not this categorical is treated as a ordered categorical.
If True, the resulting categorical will be ordered.
An ordered categorical respects, when sorted, the order of its
`categories` attribute (which in turn is the `categories` argument, if
provided).
dtype : CategoricalDtype
An instance of ``CategoricalDtype`` to use for this categorical.
.. versionadded:: 0.21.0
Attributes
----------
categories : Index
The categories of this categorical
codes : ndarray
The codes (integer positions, which point to the categories) of this
categorical, read only.
ordered : bool
Whether or not this Categorical is ordered.
dtype : CategoricalDtype
The instance of ``CategoricalDtype`` storing the ``categories``
and ``ordered``.
.. versionadded:: 0.21.0
Methods
-------
from_codes
__array__
Raises
------
ValueError
If the categories do not validate.
TypeError
If an explicit ``ordered=True`` is given but no `categories` and the
`values` are not sortable.
See Also
--------
CategoricalDtype : Type for categorical data.
CategoricalIndex : An Index with an underlying ``Categorical``.
Notes
-----
See the `user guide
<https://pandas.pydata.org/pandas-docs/stable/user_guide/categorical.html>`_
for more.
Examples
--------
>>> pd.Categorical([1, 2, 3, 1, 2, 3])
[1, 2, 3, 1, 2, 3]
Categories (3, int64): [1, 2, 3]
>>> pd.Categorical(['a', 'b', 'c', 'a', 'b', 'c'])
[a, b, c, a, b, c]
Categories (3, object): [a, b, c]
Ordered `Categoricals` can be sorted according to the custom order
of the categories and can have a min and max value.
>>> c = pd.Categorical(['a', 'b', 'c', 'a', 'b', 'c'], ordered=True,
... categories=['c', 'b', 'a'])
>>> c
[a, b, c, a, b, c]
Categories (3, object): [c < b < a]
>>> c.min()
'c'
"""
# For comparisons, so that numpy uses our implementation if the compare
# ops, which raise
__array_priority__ = 1000
_dtype = CategoricalDtype(ordered=False)
# tolist is not actually deprecated, just suppressed in the __dir__
_deprecations = PandasObject._deprecations | frozenset(["tolist"])
_typ = "categorical"
def __init__(
self, values, categories=None, ordered=None, dtype=None, fastpath=False
):
dtype = CategoricalDtype._from_values_or_dtype(
values, categories, ordered, dtype
)
# At this point, dtype is always a CategoricalDtype, but
# we may have dtype.categories be None, and we need to
# infer categories in a factorization step further below
if fastpath:
self._codes = coerce_indexer_dtype(values, dtype.categories)
self._dtype = self._dtype.update_dtype(dtype)
return
# null_mask indicates missing values we want to exclude from inference.
# This means: only missing values in list-likes (not arrays/ndframes).
null_mask = np.array(False)
# sanitize input
if is_categorical_dtype(values):
if dtype.categories is None:
dtype = CategoricalDtype(values.categories, dtype.ordered)
elif not isinstance(values, (ABCIndexClass, ABCSeries)):
# sanitize_array coerces np.nan to a string under certain versions
# of numpy
values = maybe_infer_to_datetimelike(values, convert_dates=True)
if not isinstance(values, np.ndarray):
values = _convert_to_list_like(values)
# By convention, empty lists result in object dtype:
if len(values) == 0:
sanitize_dtype = "object"
else:
sanitize_dtype = None
null_mask = isna(values)
if null_mask.any():
values = [values[idx] for idx in np.where(~null_mask)[0]]
values = sanitize_array(values, None, dtype=sanitize_dtype)
if dtype.categories is None:
try:
codes, categories = factorize(values, sort=True)
except TypeError:
codes, categories = factorize(values, sort=False)
if dtype.ordered:
# raise, as we don't have a sortable data structure and so
# the user should give us one by specifying categories
raise TypeError(
"'values' is not ordered, please "
"explicitly specify the categories order "
"by passing in a categories argument."
)
except ValueError:
# FIXME
raise NotImplementedError(
"> 1 ndim Categorical are not supported at this time"
)
# we're inferring from values
dtype = CategoricalDtype(categories, dtype.ordered)
elif is_categorical_dtype(values):
old_codes = (
values._values.codes if isinstance(values, ABCSeries) else values.codes
)
codes = _recode_for_categories(
old_codes, values.dtype.categories, dtype.categories
)
else:
codes = _get_codes_for_values(values, dtype.categories)
if null_mask.any():
# Reinsert -1 placeholders for previously removed missing values
full_codes = -np.ones(null_mask.shape, dtype=codes.dtype)
full_codes[~null_mask] = codes
codes = full_codes
self._dtype = self._dtype.update_dtype(dtype)
self._codes = coerce_indexer_dtype(codes, dtype.categories)
@property
def categories(self):
"""
The categories of this categorical.
Setting assigns new values to each category (effectively a rename of
each individual category).
The assigned value has to be a list-like object. All items must be
unique and the number of items in the new categories must be the same
as the number of items in the old categories.
Assigning to `categories` is a inplace operation!
Raises
------
ValueError
If the new categories do not validate as categories or if the
number of new categories is unequal the number of old categories
See Also
--------
rename_categories
reorder_categories
add_categories
remove_categories
remove_unused_categories
set_categories
"""
return self.dtype.categories
@categories.setter
def categories(self, categories):
new_dtype = CategoricalDtype(categories, ordered=self.ordered)
if self.dtype.categories is not None and len(self.dtype.categories) != len(
new_dtype.categories
):
raise ValueError(
"new categories need to have the same number of "
"items as the old categories!"
)
self._dtype = new_dtype
@property
def ordered(self) -> Ordered:
"""
Whether the categories have an ordered relationship.
"""
return self.dtype.ordered
@property
def dtype(self) -> CategoricalDtype:
"""
The :class:`~pandas.api.types.CategoricalDtype` for this instance.
"""
return self._dtype
@property
def _ndarray_values(self) -> np.ndarray:
return self.codes
@property
def _constructor(self) -> Type["Categorical"]:
return Categorical
@classmethod
def _from_sequence(cls, scalars, dtype=None, copy=False):
return Categorical(scalars, dtype=dtype)
def _formatter(self, boxed=False):
# Defer to CategoricalFormatter's formatter.
return None
def copy(self) -> "Categorical":
"""
Copy constructor.
"""
return self._constructor(
values=self._codes.copy(), dtype=self.dtype, fastpath=True
)
def astype(self, dtype: Dtype, copy: bool = True) -> ArrayLike:
"""
Coerce this type to another dtype
Parameters
----------
dtype : numpy dtype or pandas type
copy : bool, default True
By default, astype always returns a newly allocated object.
If copy is set to False and dtype is categorical, the original
object is returned.
"""
if is_categorical_dtype(dtype):
dtype = cast(Union[str, CategoricalDtype], dtype)
# GH 10696/18593
dtype = self.dtype.update_dtype(dtype)
self = self.copy() if copy else self
if dtype == self.dtype:
return self
return self._set_dtype(dtype)
if is_extension_array_dtype(dtype):
return array(self, dtype=dtype, copy=copy) # type: ignore # GH 28770
if is_integer_dtype(dtype) and self.isna().any():
raise ValueError("Cannot convert float NaN to integer")
return np.array(self, dtype=dtype, copy=copy)
@cache_readonly
def size(self) -> int:
"""
Return the len of myself.
"""
return self._codes.size
@cache_readonly
def itemsize(self) -> int:
"""
return the size of a single category
"""
return self.categories.itemsize
def tolist(self) -> List[Scalar]:
"""
Return a list of the values.
These are each a scalar type, which is a Python scalar
(for str, int, float) or a pandas scalar
(for Timestamp/Timedelta/Interval/Period)
"""
return list(self)
to_list = tolist
@classmethod
def _from_inferred_categories(
cls, inferred_categories, inferred_codes, dtype, true_values=None
):
"""
Construct a Categorical from inferred values.
For inferred categories (`dtype` is None) the categories are sorted.
For explicit `dtype`, the `inferred_categories` are cast to the
appropriate type.
Parameters
----------
inferred_categories : Index
inferred_codes : Index
dtype : CategoricalDtype or 'category'
true_values : list, optional
If none are provided, the default ones are
"True", "TRUE", and "true."
Returns
-------
Categorical
"""
from pandas import Index, to_numeric, to_datetime, to_timedelta
cats = Index(inferred_categories)
known_categories = (
isinstance(dtype, CategoricalDtype) and dtype.categories is not None
)
if known_categories:
# Convert to a specialized type with `dtype` if specified.
if dtype.categories.is_numeric():
cats = to_numeric(inferred_categories, errors="coerce")
elif is_datetime64_dtype(dtype.categories):
cats = to_datetime(inferred_categories, errors="coerce")
elif is_timedelta64_dtype(dtype.categories):
cats = to_timedelta(inferred_categories, errors="coerce")
elif dtype.categories.is_boolean():
if true_values is None:
true_values = ["True", "TRUE", "true"]
cats = cats.isin(true_values)
if known_categories:
# Recode from observation order to dtype.categories order.
categories = dtype.categories
codes = _recode_for_categories(inferred_codes, cats, categories)
elif not cats.is_monotonic_increasing:
# Sort categories and recode for unknown categories.
unsorted = cats.copy()
categories = cats.sort_values()
codes = _recode_for_categories(inferred_codes, unsorted, categories)
dtype = CategoricalDtype(categories, ordered=False)
else:
dtype = CategoricalDtype(cats, ordered=False)
codes = inferred_codes
return cls(codes, dtype=dtype, fastpath=True)
@classmethod
def from_codes(cls, codes, categories=None, ordered=None, dtype=None):
"""
Make a Categorical type from codes and categories or dtype.
This constructor is useful if you already have codes and
categories/dtype and so do not need the (computation intensive)
factorization step, which is usually done on the constructor.
If your data does not follow this convention, please use the normal
constructor.
Parameters
----------
codes : array-like of int
An integer array, where each integer points to a category in
categories or dtype.categories, or else is -1 for NaN.
categories : index-like, optional
The categories for the categorical. Items need to be unique.
If the categories are not given here, then they must be provided
in `dtype`.
ordered : bool, optional
Whether or not this categorical is treated as an ordered
categorical. If not given here or in `dtype`, the resulting
categorical will be unordered.
dtype : CategoricalDtype or "category", optional
If :class:`CategoricalDtype`, cannot be used together with
`categories` or `ordered`.
.. versionadded:: 0.24.0
When `dtype` is provided, neither `categories` nor `ordered`
should be provided.
Returns
-------
Categorical
Examples
--------
>>> dtype = pd.CategoricalDtype(['a', 'b'], ordered=True)
>>> pd.Categorical.from_codes(codes=[0, 1, 0, 1], dtype=dtype)
[a, b, a, b]
Categories (2, object): [a < b]
"""
dtype = CategoricalDtype._from_values_or_dtype(
categories=categories, ordered=ordered, dtype=dtype
)
if dtype.categories is None:
msg = (
"The categories must be provided in 'categories' or "
"'dtype'. Both were None."
)
raise ValueError(msg)
codes = np.asarray(codes) # #21767
if len(codes) and not is_integer_dtype(codes):
raise ValueError("codes need to be array-like integers")
if len(codes) and (codes.max() >= len(dtype.categories) or codes.min() < -1):
raise ValueError("codes need to be between -1 and len(categories)-1")
return cls(codes, dtype=dtype, fastpath=True)
def _get_codes(self):
"""
Get the codes.
Returns
-------
codes : integer array view
A non writable view of the `codes` array.
"""
v = self._codes.view()
v.flags.writeable = False
return v
def _set_codes(self, codes):
"""
Not settable by the user directly
"""
raise ValueError("cannot set Categorical codes directly")
codes = property(fget=_get_codes, fset=_set_codes, doc=_codes_doc)
def _set_categories(self, categories, fastpath=False):
"""
Sets new categories inplace
Parameters
----------
fastpath : bool, default False
Don't perform validation of the categories for uniqueness or nulls
Examples
--------
>>> c = pd.Categorical(['a', 'b'])
>>> c
[a, b]
Categories (2, object): [a, b]
>>> c._set_categories(pd.Index(['a', 'c']))
>>> c
[a, c]
Categories (2, object): [a, c]
"""
if fastpath:
new_dtype = CategoricalDtype._from_fastpath(categories, self.ordered)
else:
new_dtype = CategoricalDtype(categories, ordered=self.ordered)
if (
not fastpath
and self.dtype.categories is not None
and len(new_dtype.categories) != len(self.dtype.categories)
):
raise ValueError(
"new categories need to have the same number of "
"items than the old categories!"
)
self._dtype = new_dtype
def _set_dtype(self, dtype: CategoricalDtype) -> "Categorical":
"""
Internal method for directly updating the CategoricalDtype
Parameters
----------
dtype : CategoricalDtype
Notes
-----
We don't do any validation here. It's assumed that the dtype is
a (valid) instance of `CategoricalDtype`.
"""
codes = _recode_for_categories(self.codes, self.categories, dtype.categories)
return type(self)(codes, dtype=dtype, fastpath=True)
def set_ordered(self, value, inplace=False):
"""
Set the ordered attribute to the boolean value.
Parameters
----------
value : bool
Set whether this categorical is ordered (True) or not (False).
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to the value.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
new_dtype = CategoricalDtype(self.categories, ordered=value)
cat = self if inplace else self.copy()
cat._dtype = new_dtype
if not inplace:
return cat
def as_ordered(self, inplace=False):
"""
Set the Categorical to be ordered.
Parameters
----------
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to True.
Returns
-------
Categorical
Ordered Categorical.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
return self.set_ordered(True, inplace=inplace)
def as_unordered(self, inplace=False):
"""
Set the Categorical to be unordered.
Parameters
----------
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to False.
Returns
-------
Categorical
Unordered Categorical.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
return self.set_ordered(False, inplace=inplace)
def set_categories(self, new_categories, ordered=None, rename=False, inplace=False):
"""
Set the categories to the specified new_categories.
`new_categories` can include new categories (which will result in
unused categories) or remove old categories (which results in values
set to NaN). If `rename==True`, the categories will simple be renamed
(less or more items than in old categories will result in values set to
NaN or in unused categories respectively).
This method can be used to perform more than one action of adding,
removing, and reordering simultaneously and is therefore faster than
performing the individual steps via the more specialised methods.
On the other hand this methods does not do checks (e.g., whether the
old categories are included in the new categories on a reorder), which
can result in surprising changes, for example when using special string
dtypes, which does not considers a S1 string equal to a single char
python string.
Parameters
----------
new_categories : Index-like
The categories in new order.
ordered : bool, default False
Whether or not the categorical is treated as a ordered categorical.
If not given, do not change the ordered information.
rename : bool, default False
Whether or not the new_categories should be considered as a rename
of the old categories or as reordered categories.
inplace : bool, default False
Whether or not to reorder the categories in-place or return a copy
of this categorical with reordered categories.
Returns
-------
Categorical with reordered categories or None if inplace.
Raises
------
ValueError
If new_categories does not validate as categories
See Also
--------
rename_categories
reorder_categories
add_categories
remove_categories
remove_unused_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if ordered is None:
ordered = self.dtype.ordered
new_dtype = CategoricalDtype(new_categories, ordered=ordered)
cat = self if inplace else self.copy()
if rename:
if cat.dtype.categories is not None and len(new_dtype.categories) < len(
cat.dtype.categories
):
# remove all _codes which are larger and set to -1/NaN
cat._codes[cat._codes >= len(new_dtype.categories)] = -1
else:
codes = _recode_for_categories(
cat.codes, cat.categories, new_dtype.categories
)
cat._codes = codes
cat._dtype = new_dtype
if not inplace:
return cat
def rename_categories(self, new_categories, inplace=False):
"""
Rename categories.
Parameters
----------
new_categories : list-like, dict-like or callable
New categories which will replace old categories.
* list-like: all items must be unique and the number of items in
the new categories must match the existing number of categories.
* dict-like: specifies a mapping from
old categories to new. Categories not contained in the mapping
are passed through and extra categories in the mapping are
ignored.
.. versionadded:: 0.21.0.
* callable : a callable that is called on all items in the old
categories and whose return values comprise the new categories.
.. versionadded:: 0.23.0.
inplace : bool, default False
Whether or not to rename the categories inplace or return a copy of
this categorical with renamed categories.
Returns
-------
cat : Categorical or None
With ``inplace=False``, the new categorical is returned.
With ``inplace=True``, there is no return value.
Raises
------
ValueError
If new categories are list-like and do not have the same number of
items than the current categories or do not validate as categories
See Also
--------
reorder_categories
add_categories
remove_categories
remove_unused_categories
set_categories
Examples
--------
>>> c = pd.Categorical(['a', 'a', 'b'])
>>> c.rename_categories([0, 1])
[0, 0, 1]
Categories (2, int64): [0, 1]
For dict-like ``new_categories``, extra keys are ignored and
categories not in the dictionary are passed through
>>> c.rename_categories({'a': 'A', 'c': 'C'})
[A, A, b]
Categories (2, object): [A, b]
You may also provide a callable to create the new categories
>>> c.rename_categories(lambda x: x.upper())
[A, A, B]
Categories (2, object): [A, B]
"""
inplace = validate_bool_kwarg(inplace, "inplace")
cat = self if inplace else self.copy()
if is_dict_like(new_categories):
cat.categories = [new_categories.get(item, item) for item in cat.categories]
elif callable(new_categories):
cat.categories = [new_categories(item) for item in cat.categories]
else:
cat.categories = new_categories
if not inplace:
return cat
def reorder_categories(self, new_categories, ordered=None, inplace=False):
"""
Reorder categories as specified in new_categories.
`new_categories` need to include all old categories and no new category
items.
Parameters
----------
new_categories : Index-like
The categories in new order.
ordered : bool, optional
Whether or not the categorical is treated as a ordered categorical.
If not given, do not change the ordered information.
inplace : bool, default False
Whether or not to reorder the categories inplace or return a copy of
this categorical with reordered categories.
Returns
-------
cat : Categorical with reordered categories or None if inplace.
Raises
------
ValueError
If the new categories do not contain all old category items or any
new ones
See Also
--------
rename_categories
add_categories
remove_categories
remove_unused_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if set(self.dtype.categories) != set(new_categories):
raise ValueError(
"items in new_categories are not the same as in old categories"
)
return self.set_categories(new_categories, ordered=ordered, inplace=inplace)
def add_categories(self, new_categories, inplace=False):
"""
Add new categories.
`new_categories` will be included at the last/highest place in the
categories and will be unused directly after this call.
Parameters
----------
new_categories : category or list-like of category
The new categories to be included.
inplace : bool, default False
Whether or not to add the categories inplace or return a copy of
this categorical with added categories.
Returns
-------
cat : Categorical with new categories added or None if inplace.
Raises
------
ValueError
If the new categories include old categories or do not validate as
categories
See Also
--------
rename_categories
reorder_categories
remove_categories
remove_unused_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not is_list_like(new_categories):
new_categories = [new_categories]
already_included = set(new_categories) & set(self.dtype.categories)
if len(already_included) != 0:
raise ValueError(
f"new categories must not include old categories: {already_included}"
)
new_categories = list(self.dtype.categories) + list(new_categories)
new_dtype = CategoricalDtype(new_categories, self.ordered)
cat = self if inplace else self.copy()
cat._dtype = new_dtype
cat._codes = coerce_indexer_dtype(cat._codes, new_dtype.categories)
if not inplace:
return cat
def remove_categories(self, removals, inplace=False):
"""
Remove the specified categories.
`removals` must be included in the old categories. Values which were in
the removed categories will be set to NaN
Parameters
----------
removals : category or list of categories
The categories which should be removed.
inplace : bool, default False
Whether or not to remove the categories inplace or return a copy of
this categorical with removed categories.
Returns
-------
cat : Categorical with removed categories or None if inplace.
Raises
------
ValueError
If the removals are not contained in the categories
See Also
--------
rename_categories
reorder_categories
add_categories
remove_unused_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not is_list_like(removals):
removals = [removals]
removal_set = set(removals)
not_included = removal_set - set(self.dtype.categories)
new_categories = [c for c in self.dtype.categories if c not in removal_set]
# GH 10156
if any(isna(removals)):
not_included = {x for x in not_included if notna(x)}
new_categories = [x for x in new_categories if notna(x)]
if len(not_included) != 0:
raise ValueError(f"removals must all be in old categories: {not_included}")
return self.set_categories(
new_categories, ordered=self.ordered, rename=False, inplace=inplace
)
def remove_unused_categories(self, inplace=False):
"""
Remove categories which are not used.
Parameters
----------
inplace : bool, default False
Whether or not to drop unused categories inplace or return a copy of
this categorical with unused categories dropped.
Returns
-------
cat : Categorical with unused categories dropped or None if inplace.
See Also
--------
rename_categories
reorder_categories
add_categories
remove_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
cat = self if inplace else self.copy()
idx, inv = np.unique(cat._codes, return_inverse=True)
if idx.size != 0 and idx[0] == -1: # na sentinel
idx, inv = idx[1:], inv - 1
new_categories = cat.dtype.categories.take(idx)
new_dtype = CategoricalDtype._from_fastpath(
new_categories, ordered=self.ordered
)
cat._dtype = new_dtype
cat._codes = coerce_indexer_dtype(inv, new_dtype.categories)
if not inplace:
return cat
def map(self, mapper):
"""
Map categories using input correspondence (dict, Series, or function).
Maps the categories to new categories. If the mapping correspondence is
one-to-one the result is a :class:`~pandas.Categorical` which has the
same order property as the original, otherwise a :class:`~pandas.Index`
is returned. NaN values are unaffected.
If a `dict` or :class:`~pandas.Series` is used any unmapped category is
mapped to `NaN`. Note that if this happens an :class:`~pandas.Index`
will be returned.
Parameters
----------
mapper : function, dict, or Series
Mapping correspondence.
Returns
-------
pandas.Categorical or pandas.Index
Mapped categorical.
See Also
--------
CategoricalIndex.map : Apply a mapping correspondence on a
:class:`~pandas.CategoricalIndex`.
Index.map : Apply a mapping correspondence on an
:class:`~pandas.Index`.
Series.map : Apply a mapping correspondence on a
:class:`~pandas.Series`.
Series.apply : Apply more complex functions on a
:class:`~pandas.Series`.
Examples
--------
>>> cat = pd.Categorical(['a', 'b', 'c'])
>>> cat
[a, b, c]
Categories (3, object): [a, b, c]
>>> cat.map(lambda x: x.upper())
[A, B, C]
Categories (3, object): [A, B, C]
>>> cat.map({'a': 'first', 'b': 'second', 'c': 'third'})
[first, second, third]
Categories (3, object): [first, second, third]
If the mapping is one-to-one the ordering of the categories is
preserved:
>>> cat = pd.Categorical(['a', 'b', 'c'], ordered=True)
>>> cat
[a, b, c]
Categories (3, object): [a < b < c]
>>> cat.map({'a': 3, 'b': 2, 'c': 1})
[3, 2, 1]
Categories (3, int64): [3 < 2 < 1]
If the mapping is not one-to-one an :class:`~pandas.Index` is returned:
>>> cat.map({'a': 'first', 'b': 'second', 'c': 'first'})
Index(['first', 'second', 'first'], dtype='object')
If a `dict` is used, all unmapped categories are mapped to `NaN` and
the result is an :class:`~pandas.Index`:
>>> cat.map({'a': 'first', 'b': 'second'})
Index(['first', 'second', nan], dtype='object')
"""
new_categories = self.categories.map(mapper)
try:
return self.from_codes(
self._codes.copy(), categories=new_categories, ordered=self.ordered
)
except ValueError:
# NA values are represented in self._codes with -1
# np.take causes NA values to take final element in new_categories
if np.any(self._codes == -1):
new_categories = new_categories.insert(len(new_categories), np.nan)
return np.take(new_categories, self._codes)
__eq__ = _cat_compare_op(operator.eq)
__ne__ = _cat_compare_op(operator.ne)
__lt__ = _cat_compare_op(operator.lt)
__gt__ = _cat_compare_op(operator.gt)
__le__ = _cat_compare_op(operator.le)
__ge__ = _cat_compare_op(operator.ge)
# for Series/ndarray like compat
@property
def shape(self):
"""
Shape of the Categorical.
For internal compatibility with numpy arrays.
Returns
-------
shape : tuple
"""
return tuple([len(self._codes)])
def shift(self, periods, fill_value=None):
"""
Shift Categorical by desired number of periods.
Parameters
----------
periods : int
Number of periods to move, can be positive or negative
fill_value : object, optional
The scalar value to use for newly introduced missing values.
.. versionadded:: 0.24.0
Returns
-------
shifted : Categorical
"""
# since categoricals always have ndim == 1, an axis parameter
# doesn't make any sense here.
codes = self.codes
if codes.ndim > 1:
raise NotImplementedError("Categorical with ndim > 1.")
if np.prod(codes.shape) and (periods != 0):
codes = np.roll(codes, ensure_platform_int(periods), axis=0)
if isna(fill_value):
fill_value = -1
elif fill_value in self.categories:
fill_value = self.categories.get_loc(fill_value)
else:
raise ValueError(
f"'fill_value={fill_value}' is not present "
"in this Categorical's categories"
)
if periods > 0:
codes[:periods] = fill_value
else:
codes[periods:] = fill_value
return self.from_codes(codes, dtype=self.dtype)
def __array__(self, dtype=None) -> np.ndarray:
"""
The numpy array interface.
Returns
-------
numpy.array
A numpy array of either the specified dtype or,
if dtype==None (default), the same dtype as
categorical.categories.dtype.
"""
ret = take_1d(self.categories.values, self._codes)
if dtype and not is_dtype_equal(dtype, self.categories.dtype):
return np.asarray(ret, dtype)
if is_extension_array_dtype(ret):
# When we're a Categorical[ExtensionArray], like Interval,
# we need to ensure __array__ get's all the way to an
# ndarray.
ret = np.asarray(ret)
return ret
def __array_ufunc__(self, ufunc, method, *inputs, **kwargs):
# for binary ops, use our custom dunder methods
result = ops.maybe_dispatch_ufunc_to_dunder_op(
self, ufunc, method, *inputs, **kwargs
)
if result is not NotImplemented:
return result
# for all other cases, raise for now (similarly as what happens in
# Series.__array_prepare__)
raise TypeError(
f"Object with dtype {self.dtype} cannot perform "
f"the numpy op {ufunc.__name__}"
)
def __setstate__(self, state):
"""Necessary for making this object picklable"""
if not isinstance(state, dict):
raise Exception("invalid pickle state")
# compat with pre 0.21.0 CategoricalDtype change
if "_dtype" not in state:
state["_dtype"] = CategoricalDtype(state["_categories"], state["_ordered"])
for k, v in state.items():
setattr(self, k, v)
@property
def T(self):
"""
Return transposed numpy array.
"""
return self
@property
def nbytes(self):
return self._codes.nbytes + self.dtype.categories.values.nbytes
def memory_usage(self, deep=False):
"""
Memory usage of my values
Parameters
----------
deep : bool
Introspect the data deeply, interrogate
`object` dtypes for system-level memory consumption
Returns
-------
bytes used
Notes
-----
Memory usage does not include memory consumed by elements that
are not components of the array if deep=False
See Also
--------
numpy.ndarray.nbytes
"""
return self._codes.nbytes + self.dtype.categories.memory_usage(deep=deep)
@Substitution(klass="Categorical")
@Appender(_shared_docs["searchsorted"])
def searchsorted(self, value, side="left", sorter=None):
# searchsorted is very performance sensitive. By converting codes
# to same dtype as self.codes, we get much faster performance.
if is_scalar(value):
codes = self.categories.get_loc(value)
codes = self.codes.dtype.type(codes)
else:
locs = [self.categories.get_loc(x) for x in value]
codes = np.array(locs, dtype=self.codes.dtype)
return self.codes.searchsorted(codes, side=side, sorter=sorter)
def isna(self):
"""
Detect missing values
Missing values (-1 in .codes) are detected.
Returns
-------
a boolean array of whether my values are null
See Also
--------
isna : Top-level isna.
isnull : Alias of isna.
Categorical.notna : Boolean inverse of Categorical.isna.
"""
ret = self._codes == -1
return ret
isnull = isna
def notna(self):
"""
Inverse of isna
Both missing values (-1 in .codes) and NA as a category are detected as
null.
Returns
-------
a boolean array of whether my values are not null
See Also
--------
notna : Top-level notna.
notnull : Alias of notna.
Categorical.isna : Boolean inverse of Categorical.notna.
"""
return ~self.isna()
notnull = notna
def put(self, *args, **kwargs):
"""
Replace specific elements in the Categorical with given values.
"""
raise NotImplementedError(("'put' is not yet implemented for Categorical"))
def dropna(self):
"""
Return the Categorical without null values.
Missing values (-1 in .codes) are detected.
Returns
-------
valid : Categorical
"""
result = self[self.notna()]
return result
def value_counts(self, dropna=True):
"""
Return a Series containing counts of each category.
Every category will have an entry, even those with a count of 0.
Parameters
----------
dropna : bool, default True
Don't include counts of NaN.
Returns
-------
counts : Series
See Also
--------
Series.value_counts
"""
from pandas import Series, CategoricalIndex
code, cat = self._codes, self.categories
ncat, mask = len(cat), 0 <= code
ix, clean = np.arange(ncat), mask.all()
if dropna or clean:
obs = code if clean else code[mask]
count = np.bincount(obs, minlength=ncat or 0)
else:
count = np.bincount(np.where(mask, code, ncat))
ix = np.append(ix, -1)
ix = self._constructor(ix, dtype=self.dtype, fastpath=True)
return Series(count, index=CategoricalIndex(ix), dtype="int64")
def _internal_get_values(self):
"""
Return the values.
For internal compatibility with pandas formatting.
Returns
-------
np.ndarray or Index
A numpy array of the same dtype as categorical.categories.dtype or
Index if datetime / periods.
"""
# if we are a datetime and period index, return Index to keep metadata
if needs_i8_conversion(self.categories):
return self.categories.take(self._codes, fill_value=np.nan)
elif is_integer_dtype(self.categories) and -1 in self._codes:
return self.categories.astype("object").take(self._codes, fill_value=np.nan)
return np.array(self)
def check_for_ordered(self, op):
""" assert that we are ordered """
if not self.ordered:
raise TypeError(
f"Categorical is not ordered for operation {op}\n"
"you can use .as_ordered() to change the "
"Categorical to an ordered one\n"
)
def _values_for_argsort(self):
return self._codes.copy()
def argsort(self, ascending=True, kind="quicksort", *args, **kwargs):
"""
Return the indices that would sort the Categorical.
.. versionchanged:: 0.25.0
Changed to sort missing values at the end.
Parameters
----------
ascending : bool, default True
Whether the indices should result in an ascending
or descending sort.
kind : {'quicksort', 'mergesort', 'heapsort'}, optional
Sorting algorithm.
*args, **kwargs:
passed through to :func:`numpy.argsort`.
Returns
-------
numpy.array
See Also
--------
numpy.ndarray.argsort
Notes
-----
While an ordering is applied to the category values, arg-sorting
in this context refers more to organizing and grouping together
based on matching category values. Thus, this function can be
called on an unordered Categorical instance unlike the functions
'Categorical.min' and 'Categorical.max'.
Examples
--------
>>> pd.Categorical(['b', 'b', 'a', 'c']).argsort()
array([2, 0, 1, 3])
>>> cat = pd.Categorical(['b', 'b', 'a', 'c'],
... categories=['c', 'b', 'a'],
... ordered=True)
>>> cat.argsort()
array([3, 0, 1, 2])
Missing values are placed at the end
>>> cat = pd.Categorical([2, None, 1])
>>> cat.argsort()
array([2, 0, 1])
"""
return super().argsort(ascending=ascending, kind=kind, *args, **kwargs)
def sort_values(self, inplace=False, ascending=True, na_position="last"):
"""
Sort the Categorical by category value returning a new
Categorical by default.
While an ordering is applied to the category values, sorting in this
context refers more to organizing and grouping together based on
matching category values. Thus, this function can be called on an
unordered Categorical instance unlike the functions 'Categorical.min'
and 'Categorical.max'.
Parameters
----------
inplace : bool, default False
Do operation in place.
ascending : bool, default True
Order ascending. Passing False orders descending. The
ordering parameter provides the method by which the
category values are organized.
na_position : {'first', 'last'} (optional, default='last')
'first' puts NaNs at the beginning
'last' puts NaNs at the end
Returns
-------
Categorical or None
See Also
--------
Categorical.sort
Series.sort_values
Examples
--------
>>> c = pd.Categorical([1, 2, 2, 1, 5])
>>> c
[1, 2, 2, 1, 5]
Categories (3, int64): [1, 2, 5]
>>> c.sort_values()
[1, 1, 2, 2, 5]
Categories (3, int64): [1, 2, 5]
>>> c.sort_values(ascending=False)
[5, 2, 2, 1, 1]
Categories (3, int64): [1, 2, 5]
Inplace sorting can be done as well:
>>> c.sort_values(inplace=True)
>>> c
[1, 1, 2, 2, 5]
Categories (3, int64): [1, 2, 5]
>>>
>>> c = pd.Categorical([1, 2, 2, 1, 5])
'sort_values' behaviour with NaNs. Note that 'na_position'
is independent of the 'ascending' parameter:
>>> c = pd.Categorical([np.nan, 2, 2, np.nan, 5])
>>> c
[NaN, 2.0, 2.0, NaN, 5.0]
Categories (2, int64): [2, 5]
>>> c.sort_values()
[2.0, 2.0, 5.0, NaN, NaN]
Categories (2, int64): [2, 5]
>>> c.sort_values(ascending=False)
[5.0, 2.0, 2.0, NaN, NaN]
Categories (2, int64): [2, 5]
>>> c.sort_values(na_position='first')
[NaN, NaN, 2.0, 2.0, 5.0]
Categories (2, int64): [2, 5]
>>> c.sort_values(ascending=False, na_position='first')
[NaN, NaN, 5.0, 2.0, 2.0]
Categories (2, int64): [2, 5]
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if na_position not in ["last", "first"]:
raise ValueError(f"invalid na_position: {repr(na_position)}")
sorted_idx = nargsort(self, ascending=ascending, na_position=na_position)
if inplace:
self._codes = self._codes[sorted_idx]
else:
return self._constructor(
values=self._codes[sorted_idx], dtype=self.dtype, fastpath=True
)
def _values_for_rank(self):
"""
For correctly ranking ordered categorical data. See GH#15420
Ordered categorical data should be ranked on the basis of
codes with -1 translated to NaN.
Returns
-------
numpy.array
"""
from pandas import Series
if self.ordered:
values = self.codes
mask = values == -1
if mask.any():
values = values.astype("float64")
values[mask] = np.nan
elif self.categories.is_numeric():
values = np.array(self)
else:
# reorder the categories (so rank can use the float codes)
# instead of passing an object array to rank
values = np.array(
self.rename_categories(Series(self.categories).rank().values)
)
return values
def view(self, dtype=None):
if dtype is not None:
raise NotImplementedError(dtype)
return self._constructor(values=self._codes, dtype=self.dtype, fastpath=True)
def to_dense(self):
"""
Return my 'dense' representation
For internal compatibility with numpy arrays.
Returns
-------
dense : array
"""
return np.asarray(self)
def fillna(self, value=None, method=None, limit=None):
"""
Fill NA/NaN values using the specified method.
Parameters
----------
value : scalar, dict, Series
If a scalar value is passed it is used to fill all missing values.
Alternatively, a Series or dict can be used to fill in different
values for each index. The value should not be a list. The
value(s) passed should either be in the categories or should be
NaN.
method : {'backfill', 'bfill', 'pad', 'ffill', None}, default None
Method to use for filling holes in reindexed Series
pad / ffill: propagate last valid observation forward to next valid
backfill / bfill: use NEXT valid observation to fill gap
limit : int, default None
(Not implemented yet for Categorical!)
If method is specified, this is the maximum number of consecutive
NaN values to forward/backward fill. In other words, if there is
a gap with more than this number of consecutive NaNs, it will only
be partially filled. If method is not specified, this is the
maximum number of entries along the entire axis where NaNs will be
filled.
Returns
-------
filled : Categorical with NA/NaN filled
"""
value, method = validate_fillna_kwargs(
value, method, validate_scalar_dict_value=False
)
if value is None:
value = np.nan
if limit is not None:
raise NotImplementedError(
"specifying a limit for fillna has not been implemented yet"
)
codes = self._codes
# pad / bfill
if method is not None:
values = self.to_dense().reshape(-1, len(self))
values = interpolate_2d(values, method, 0, None, value).astype(
self.categories.dtype
)[0]
codes = _get_codes_for_values(values, self.categories)
else:
# If value is a dict or a Series (a dict value has already
# been converted to a Series)
if isinstance(value, ABCSeries):
if not value[~value.isin(self.categories)].isna().all():
raise ValueError("fill value must be in categories")
values_codes = _get_codes_for_values(value, self.categories)
indexer = np.where(codes == -1)
codes[indexer] = values_codes[indexer]
# If value is not a dict or Series it should be a scalar
elif is_hashable(value):
if not isna(value) and value not in self.categories:
raise ValueError("fill value must be in categories")
mask = codes == -1
if mask.any():
codes = codes.copy()
if isna(value):
codes[mask] = -1
else:
codes[mask] = self.categories.get_loc(value)
else:
raise TypeError(
f"'value' parameter must be a scalar, dict "
f"or Series, but you passed a {type(value).__name__}"
)
return self._constructor(codes, dtype=self.dtype, fastpath=True)
def take(self, indexer, allow_fill: bool = False, fill_value=None):
"""
Take elements from the Categorical.
Parameters
----------
indexer : sequence of int
The indices in `self` to take. The meaning of negative values in
`indexer` depends on the value of `allow_fill`.
allow_fill : bool, default False
How to handle negative values in `indexer`.
* False: negative values in `indices` indicate positional indices
from the right. This is similar to
:func:`numpy.take`.
* True: negative values in `indices` indicate missing values
(the default). These values are set to `fill_value`. Any other
other negative values raise a ``ValueError``.
.. versionchanged:: 1.0.0
Default value changed from ``True`` to ``False``.
fill_value : object
The value to use for `indices` that are missing (-1), when
``allow_fill=True``. This should be the category, i.e. a value
in ``self.categories``, not a code.
Returns
-------
Categorical
This Categorical will have the same categories and ordered as
`self`.
See Also
--------
Series.take : Similar method for Series.
numpy.ndarray.take : Similar method for NumPy arrays.
Examples
--------
>>> cat = pd.Categorical(['a', 'a', 'b'])
>>> cat
[a, a, b]
Categories (2, object): [a, b]
Specify ``allow_fill==False`` to have negative indices mean indexing
from the right.
>>> cat.take([0, -1, -2], allow_fill=False)
[a, b, a]
Categories (2, object): [a, b]
With ``allow_fill=True``, indices equal to ``-1`` mean "missing"
values that should be filled with the `fill_value`, which is
``np.nan`` by default.
>>> cat.take([0, -1, -1], allow_fill=True)
[a, NaN, NaN]
Categories (2, object): [a, b]
The fill value can be specified.
>>> cat.take([0, -1, -1], allow_fill=True, fill_value='a')
[a, a, a]
Categories (3, object): [a, b]
Specifying a fill value that's not in ``self.categories``
will raise a ``TypeError``.
"""
indexer = np.asarray(indexer, dtype=np.intp)
dtype = self.dtype
if isna(fill_value):
fill_value = -1
elif allow_fill:
# convert user-provided `fill_value` to codes
if fill_value in self.categories:
fill_value = self.categories.get_loc(fill_value)
else:
msg = (
f"'fill_value' ('{fill_value}') is not in this "
"Categorical's categories."
)
raise TypeError(msg)
codes = take(self._codes, indexer, allow_fill=allow_fill, fill_value=fill_value)
result = type(self).from_codes(codes, dtype=dtype)
return result
def take_nd(self, indexer, allow_fill: bool = False, fill_value=None):
# GH#27745 deprecate alias that other EAs dont have
warn(
"Categorical.take_nd is deprecated, use Categorical.take instead",
FutureWarning,
stacklevel=2,
)
return self.take(indexer, allow_fill=allow_fill, fill_value=fill_value)
def __len__(self) -> int:
"""
The length of this Categorical.
"""
return len(self._codes)
def __iter__(self):
"""
Returns an Iterator over the values of this Categorical.
"""
return iter(self._internal_get_values().tolist())
def __contains__(self, key) -> bool:
"""
Returns True if `key` is in this Categorical.
"""
# if key is a NaN, check if any NaN is in self.
if is_scalar(key) and isna(key):
return self.isna().any()
return contains(self, key, container=self._codes)
def _tidy_repr(self, max_vals=10, footer=True) -> str:
""" a short repr displaying only max_vals and an optional (but default
footer)
"""
num = max_vals // 2
head = self[:num]._get_repr(length=False, footer=False)
tail = self[-(max_vals - num) :]._get_repr(length=False, footer=False)
result = f"{head[:-1]}, ..., {tail[1:]}"
if footer:
result = f"{result}\n{self._repr_footer()}"
return str(result)
def _repr_categories(self):
"""
return the base repr for the categories
"""
max_categories = (
10
if get_option("display.max_categories") == 0
else get_option("display.max_categories")
)
from pandas.io.formats import format as fmt
if len(self.categories) > max_categories:
num = max_categories // 2
head = fmt.format_array(self.categories[:num], None)
tail = fmt.format_array(self.categories[-num:], None)
category_strs = head + ["..."] + tail
else:
category_strs = fmt.format_array(self.categories, None)
# Strip all leading spaces, which format_array adds for columns...
category_strs = [x.strip() for x in category_strs]
return category_strs
def _repr_categories_info(self) -> str:
"""
Returns a string representation of the footer.
"""
category_strs = self._repr_categories()
dtype = str(self.categories.dtype)
levheader = f"Categories ({len(self.categories)}, {dtype}): "
width, height = get_terminal_size()
max_width = get_option("display.width") or width
if console.in_ipython_frontend():
# 0 = no breaks
max_width = 0
levstring = ""
start = True
cur_col_len = len(levheader) # header
sep_len, sep = (3, " < ") if self.ordered else (2, ", ")
linesep = sep.rstrip() + "\n" # remove whitespace
for val in category_strs:
if max_width != 0 and cur_col_len + sep_len + len(val) > max_width:
levstring += linesep + (" " * (len(levheader) + 1))
cur_col_len = len(levheader) + 1 # header + a whitespace
elif not start:
levstring += sep
cur_col_len += len(val)
levstring += val
start = False
# replace to simple save space by
return levheader + "[" + levstring.replace(" < ... < ", " ... ") + "]"
def _repr_footer(self) -> str:
info = self._repr_categories_info()
return f"Length: {len(self)}\n{info}"
def _get_repr(self, length=True, na_rep="NaN", footer=True) -> str:
from pandas.io.formats import format as fmt
formatter = fmt.CategoricalFormatter(
self, length=length, na_rep=na_rep, footer=footer
)
result = formatter.to_string()
return str(result)
def __repr__(self) -> str:
"""
String representation.
"""
_maxlen = 10
if len(self._codes) > _maxlen:
result = self._tidy_repr(_maxlen)
elif len(self._codes) > 0:
result = self._get_repr(length=len(self) > _maxlen)
else:
msg = self._get_repr(length=False, footer=True).replace("\n", ", ")
result = f"[], {msg}"
return result
def _maybe_coerce_indexer(self, indexer):
"""
return an indexer coerced to the codes dtype
"""
if isinstance(indexer, np.ndarray) and indexer.dtype.kind == "i":
indexer = indexer.astype(self._codes.dtype)
return indexer
def __getitem__(self, key):
"""
Return an item.
"""
if isinstance(key, (int, np.integer)):
i = self._codes[key]
if i == -1:
return np.nan
else:
return self.categories[i]
key = check_array_indexer(self, key)
result = self._codes[key]
if result.ndim > 1:
deprecate_ndim_indexing(result)
return result
return self._constructor(result, dtype=self.dtype, fastpath=True)
def __setitem__(self, key, value):
"""
Item assignment.
Raises
------
ValueError
If (one or more) Value is not in categories or if a assigned
`Categorical` does not have the same categories
"""
value = extract_array(value, extract_numpy=True)
# require identical categories set
if isinstance(value, Categorical):
if not is_dtype_equal(self, value):
raise ValueError(
"Cannot set a Categorical with another, "
"without identical categories"
)
if not self.categories.equals(value.categories):
new_codes = _recode_for_categories(
value.codes, value.categories, self.categories
)
value = Categorical.from_codes(new_codes, dtype=self.dtype)
rvalue = value if is_list_like(value) else [value]
from pandas import Index
to_add = Index(rvalue).difference(self.categories)
# no assignments of values not in categories, but it's always ok to set
# something to np.nan
if len(to_add) and not isna(to_add).all():
raise ValueError(
"Cannot setitem on a Categorical with a new "
"category, set the categories first"
)
# set by position
if isinstance(key, (int, np.integer)):
pass
# tuple of indexers (dataframe)
elif isinstance(key, tuple):
# only allow 1 dimensional slicing, but can
# in a 2-d case be passd (slice(None),....)
if len(key) == 2:
if not com.is_null_slice(key[0]):
raise AssertionError("invalid slicing for a 1-ndim categorical")
key = key[1]
elif len(key) == 1:
key = key[0]
else:
raise AssertionError("invalid slicing for a 1-ndim categorical")
# slicing in Series or Categorical
elif isinstance(key, slice):
pass
# else: array of True/False in Series or Categorical
lindexer = self.categories.get_indexer(rvalue)
lindexer = self._maybe_coerce_indexer(lindexer)
key = check_array_indexer(self, key)
self._codes[key] = lindexer
def _reverse_indexer(self) -> Dict[Hashable, np.ndarray]:
"""
Compute the inverse of a categorical, returning
a dict of categories -> indexers.
*This is an internal function*
Returns
-------
dict of categories -> indexers
Examples
--------
>>> c = pd.Categorical(list('aabca'))
>>> c
[a, a, b, c, a]
Categories (3, object): [a, b, c]
>>> c.categories
Index(['a', 'b', 'c'], dtype='object')
>>> c.codes
array([0, 0, 1, 2, 0], dtype=int8)
>>> c._reverse_indexer()
{'a': array([0, 1, 4]), 'b': array([2]), 'c': array([3])}
"""
categories = self.categories
r, counts = libalgos.groupsort_indexer(
self.codes.astype("int64"), categories.size
)
counts = counts.cumsum()
_result = (r[start:end] for start, end in zip(counts, counts[1:]))
result = dict(zip(categories, _result))
return result
# reduction ops #
def _reduce(self, name, axis=0, **kwargs):
func = getattr(self, name, None)
if func is None:
raise TypeError(f"Categorical cannot perform the operation {name}")
return func(**kwargs)
@deprecate_kwarg(old_arg_name="numeric_only", new_arg_name="skipna")
def min(self, skipna=True):
"""
The minimum value of the object.
Only ordered `Categoricals` have a minimum!
.. versionchanged:: 1.0.0
Returns an NA value on empty arrays
Raises
------
TypeError
If the `Categorical` is not `ordered`.
Returns
-------
min : the minimum of this `Categorical`
"""
self.check_for_ordered("min")
if not len(self._codes):
return self.dtype.na_value
good = self._codes != -1
if not good.all():
if skipna:
pointer = self._codes[good].min()
else:
return np.nan
else:
pointer = self._codes.min()
return self.categories[pointer]
@deprecate_kwarg(old_arg_name="numeric_only", new_arg_name="skipna")
def max(self, skipna=True):
"""
The maximum value of the object.
Only ordered `Categoricals` have a maximum!
.. versionchanged:: 1.0.0
Returns an NA value on empty arrays
Raises
------
TypeError
If the `Categorical` is not `ordered`.
Returns
-------
max : the maximum of this `Categorical`
"""
self.check_for_ordered("max")
if not len(self._codes):
return self.dtype.na_value
good = self._codes != -1
if not good.all():
if skipna:
pointer = self._codes[good].max()
else:
return np.nan
else:
pointer = self._codes.max()
return self.categories[pointer]
def mode(self, dropna=True):
"""
Returns the mode(s) of the Categorical.
Always returns `Categorical` even if only one value.
Parameters
----------
dropna : bool, default True
Don't consider counts of NaN/NaT.
.. versionadded:: 0.24.0
Returns
-------
modes : `Categorical` (sorted)
"""
codes = self._codes
if dropna:
good = self._codes != -1
codes = self._codes[good]
codes = sorted(htable.mode_int64(ensure_int64(codes), dropna))
return self._constructor(values=codes, dtype=self.dtype, fastpath=True)
def unique(self):
"""
Return the ``Categorical`` which ``categories`` and ``codes`` are
unique. Unused categories are NOT returned.
- unordered category: values and categories are sorted by appearance
order.
- ordered category: values are sorted by appearance order, categories
keeps existing order.
Returns
-------
unique values : ``Categorical``
Examples
--------
An unordered Categorical will return categories in the
order of appearance.
>>> pd.Categorical(list('baabc'))
[b, a, c]
Categories (3, object): [b, a, c]
>>> pd.Categorical(list('baabc'), categories=list('abc'))
[b, a, c]
Categories (3, object): [b, a, c]
An ordered Categorical preserves the category ordering.
>>> pd.Categorical(list('baabc'),
... categories=list('abc'),
... ordered=True)
[b, a, c]
Categories (3, object): [a < b < c]
See Also
--------
unique
CategoricalIndex.unique
Series.unique
"""
# unlike np.unique, unique1d does not sort
unique_codes = unique1d(self.codes)
cat = self.copy()
# keep nan in codes
cat._codes = unique_codes
# exclude nan from indexer for categories
take_codes = unique_codes[unique_codes != -1]
if self.ordered:
take_codes = np.sort(take_codes)
return cat.set_categories(cat.categories.take(take_codes))
def _values_for_factorize(self):
codes = self.codes.astype("int64")
return codes, -1
@classmethod
def _from_factorized(cls, uniques, original):
return original._constructor(
original.categories.take(uniques), dtype=original.dtype
)
def equals(self, other):
"""
Returns True if categorical arrays are equal.
Parameters
----------
other : `Categorical`
Returns
-------
bool
"""
if self.is_dtype_equal(other):
if self.categories.equals(other.categories):
# fastpath to avoid re-coding
other_codes = other._codes
else:
other_codes = _recode_for_categories(
other.codes, other.categories, self.categories
)
return np.array_equal(self._codes, other_codes)
return False
def is_dtype_equal(self, other):
"""
Returns True if categoricals are the same dtype
same categories, and same ordered
Parameters
----------
other : Categorical
Returns
-------
bool
"""
try:
return hash(self.dtype) == hash(other.dtype)
except (AttributeError, TypeError):
return False
def describe(self):
"""
Describes this Categorical
Returns
-------
description: `DataFrame`
A dataframe with frequency and counts by category.
"""
counts = self.value_counts(dropna=False)
freqs = counts / float(counts.sum())
from pandas.core.reshape.concat import concat
result = concat([counts, freqs], axis=1)
result.columns = ["counts", "freqs"]
result.index.name = "categories"
return result
@Substitution(klass="Categorical")
@Appender(_extension_array_shared_docs["repeat"])
def repeat(self, repeats, axis=None):
nv.validate_repeat(tuple(), dict(axis=axis))
codes = self._codes.repeat(repeats)
return self._constructor(values=codes, dtype=self.dtype, fastpath=True)
# Implement the ExtensionArray interface
@property
def _can_hold_na(self):
return True
@classmethod
def _concat_same_type(self, to_concat):
from pandas.core.dtypes.concat import concat_categorical
return concat_categorical(to_concat)
def isin(self, values):
"""
Check whether `values` are contained in Categorical.
Return a boolean NumPy Array showing whether each element in
the Categorical matches an element in the passed sequence of
`values` exactly.
Parameters
----------
values : set or list-like
The sequence of values to test. Passing in a single string will
raise a ``TypeError``. Instead, turn a single string into a
list of one element.
Returns
-------
isin : numpy.ndarray (bool dtype)
Raises
------
TypeError
* If `values` is not a set or list-like
See Also
--------
pandas.Series.isin : Equivalent method on Series.
Examples
--------
>>> s = pd.Categorical(['lama', 'cow', 'lama', 'beetle', 'lama',
... 'hippo'])
>>> s.isin(['cow', 'lama'])
array([ True, True, True, False, True, False])
Passing a single string as ``s.isin('lama')`` will raise an error. Use
a list of one element instead:
>>> s.isin(['lama'])
array([ True, False, True, False, True, False])
"""
if not is_list_like(values):
values_type = type(values).__name__
raise TypeError(
"only list-like objects are allowed to be passed "
f"to isin(), you passed a [{values_type}]"
)
values = sanitize_array(values, None, None)
null_mask = np.asarray(isna(values))
code_values = self.categories.get_indexer(values)
code_values = code_values[null_mask | (code_values >= 0)]
return algorithms.isin(self.codes, code_values)
def replace(self, to_replace, value, inplace: bool = False):
"""
Replaces all instances of one value with another
Parameters
----------
to_replace: object
The value to be replaced
value: object
The value to replace it with
inplace: bool
Whether the operation is done in-place
Returns
-------
None if inplace is True, otherwise the new Categorical after replacement
Examples
--------
>>> s = pd.Categorical([1, 2, 1, 3])
>>> s.replace(1, 3)
[3, 3, 2, 3]
Categories (2, int64): [2, 3]
"""
inplace = validate_bool_kwarg(inplace, "inplace")
cat = self if inplace else self.copy()
if to_replace in cat.categories:
if isna(value):
cat.remove_categories(to_replace, inplace=True)
else:
categories = cat.categories.tolist()
index = categories.index(to_replace)
if value in cat.categories:
value_index = categories.index(value)
cat._codes[cat._codes == index] = value_index
cat.remove_categories(to_replace, inplace=True)
else:
categories[index] = value
cat.rename_categories(categories, inplace=True)
if not inplace:
return cat
# The Series.cat accessor
@delegate_names(
delegate=Categorical, accessors=["categories", "ordered"], typ="property"
)
@delegate_names(
delegate=Categorical,
accessors=[
"rename_categories",
"reorder_categories",
"add_categories",
"remove_categories",
"remove_unused_categories",
"set_categories",
"as_ordered",
"as_unordered",
],
typ="method",
)
class CategoricalAccessor(PandasDelegate, PandasObject, NoNewAttributesMixin):
"""
Accessor object for categorical properties of the Series values.
Be aware that assigning to `categories` is a inplace operation, while all
methods return new categorical data per default (but can be called with
`inplace=True`).
Parameters
----------
data : Series or CategoricalIndex
Examples
--------
>>> s.cat.categories
>>> s.cat.categories = list('abc')
>>> s.cat.rename_categories(list('cab'))
>>> s.cat.reorder_categories(list('cab'))
>>> s.cat.add_categories(['d','e'])
>>> s.cat.remove_categories(['d'])
>>> s.cat.remove_unused_categories()
>>> s.cat.set_categories(list('abcde'))
>>> s.cat.as_ordered()
>>> s.cat.as_unordered()
"""
def __init__(self, data):
self._validate(data)
self._parent = data.values
self._index = data.index
self._name = data.name
self._freeze()
@staticmethod
def _validate(data):
if not is_categorical_dtype(data.dtype):
raise AttributeError("Can only use .cat accessor with a 'category' dtype")
def _delegate_property_get(self, name):
return getattr(self._parent, name)
def _delegate_property_set(self, name, new_values):
return setattr(self._parent, name, new_values)
@property
def codes(self):
"""
Return Series of codes as well as the index.
"""
from pandas import Series
return Series(self._parent.codes, index=self._index)
def _delegate_method(self, name, *args, **kwargs):
from pandas import Series
method = getattr(self._parent, name)
res = method(*args, **kwargs)
if res is not None:
return Series(res, index=self._index, name=self._name)
# utility routines
def _get_codes_for_values(values, categories):
"""
utility routine to turn values into codes given the specified categories
"""
dtype_equal = is_dtype_equal(values.dtype, categories.dtype)
if dtype_equal:
# To prevent erroneous dtype coercion in _get_data_algo, retrieve
# the underlying numpy array. gh-22702
values = getattr(values, "_ndarray_values", values)
categories = getattr(categories, "_ndarray_values", categories)
elif is_extension_array_dtype(categories.dtype) and is_object_dtype(values):
# Support inferring the correct extension dtype from an array of
# scalar objects. e.g.
# Categorical(array[Period, Period], categories=PeriodIndex(...))
cls = categories.dtype.construct_array_type()
values = try_cast_to_ea(cls, values)
if not isinstance(values, cls):
# exception raised in _from_sequence
values = ensure_object(values)
categories = ensure_object(categories)
else:
values = ensure_object(values)
categories = ensure_object(categories)
hash_klass, vals = _get_data_algo(values)
_, cats = _get_data_algo(categories)
t = hash_klass(len(cats))
t.map_locations(cats)
return coerce_indexer_dtype(t.lookup(vals), cats)
def _recode_for_categories(codes: np.ndarray, old_categories, new_categories):
"""
Convert a set of codes for to a new set of categories
Parameters
----------
codes : np.ndarray
old_categories, new_categories : Index
Returns
-------
new_codes : np.ndarray[np.int64]
Examples
--------
>>> old_cat = pd.Index(['b', 'a', 'c'])
>>> new_cat = pd.Index(['a', 'b'])
>>> codes = np.array([0, 1, 1, 2])
>>> _recode_for_categories(codes, old_cat, new_cat)
array([ 1, 0, 0, -1])
"""
if len(old_categories) == 0:
# All null anyway, so just retain the nulls
return codes.copy()
elif new_categories.equals(old_categories):
# Same categories, so no need to actually recode
return codes.copy()
indexer = coerce_indexer_dtype(
new_categories.get_indexer(old_categories), new_categories
)
new_codes = take_1d(indexer, codes.copy(), fill_value=-1)
return new_codes
def _convert_to_list_like(list_like):
if hasattr(list_like, "dtype"):
return list_like
if isinstance(list_like, list):
return list_like
if is_sequence(list_like) or isinstance(list_like, tuple) or is_iterator(list_like):
return list(list_like)
elif is_scalar(list_like):
return [list_like]
else:
# TODO: is this reached?
return [list_like]
def factorize_from_iterable(values):
"""
Factorize an input `values` into `categories` and `codes`. Preserves
categorical dtype in `categories`.
*This is an internal function*
Parameters
----------
values : list-like
Returns
-------
codes : ndarray
categories : Index
If `values` has a categorical dtype, then `categories` is
a CategoricalIndex keeping the categories and order of `values`.
"""
if not is_list_like(values):
raise TypeError("Input must be list-like")
if is_categorical_dtype(values):
values = extract_array(values)
# The Categorical we want to build has the same categories
# as values but its codes are by def [0, ..., len(n_categories) - 1]
cat_codes = np.arange(len(values.categories), dtype=values.codes.dtype)
categories = Categorical.from_codes(cat_codes, dtype=values.dtype)
codes = values.codes
else:
# The value of ordered is irrelevant since we don't use cat as such,
# but only the resulting categories, the order of which is independent
# from ordered. Set ordered to False as default. See GH #15457
cat = Categorical(values, ordered=False)
categories = cat.categories
codes = cat.codes
return codes, categories
def factorize_from_iterables(iterables):
"""
A higher-level wrapper over `factorize_from_iterable`.
*This is an internal function*
Parameters
----------
iterables : list-like of list-likes
Returns
-------
codes_list : list of ndarrays
categories_list : list of Indexes
Notes
-----
See `factorize_from_iterable` for more info.
"""
if len(iterables) == 0:
# For consistency, it should return a list of 2 lists.
return [[], []]
return map(list, zip(*(factorize_from_iterable(it) for it in iterables)))
import operator
from shutil import get_terminal_size
from typing import Dict, Hashable, List, Type, Union, cast
from warnings import warn
import numpy as np
from pandas._config import get_option
from pandas._libs import algos as libalgos, hashtable as htable
from pandas._typing import ArrayLike, Dtype, Ordered, Scalar
from pandas.compat.numpy import function as nv
from pandas.util._decorators import (
Appender,
Substitution,
cache_readonly,
deprecate_kwarg,
)
from pandas.util._validators import validate_bool_kwarg, validate_fillna_kwargs
from pandas.core.dtypes.cast import coerce_indexer_dtype, maybe_infer_to_datetimelike
from pandas.core.dtypes.common import (
ensure_int64,
ensure_object,
ensure_platform_int,
is_categorical_dtype,
is_datetime64_dtype,
is_dict_like,
is_dtype_equal,
is_extension_array_dtype,
is_integer_dtype,
is_iterator,
is_list_like,
is_object_dtype,
is_scalar,
is_sequence,
is_timedelta64_dtype,
needs_i8_conversion,
)
from pandas.core.dtypes.dtypes import CategoricalDtype
from pandas.core.dtypes.generic import ABCIndexClass, ABCSeries
from pandas.core.dtypes.inference import is_hashable
from pandas.core.dtypes.missing import isna, notna
from pandas.core import ops
from pandas.core.accessor import PandasDelegate, delegate_names
import pandas.core.algorithms as algorithms
from pandas.core.algorithms import _get_data_algo, factorize, take, take_1d, unique1d
from pandas.core.arrays.base import (
ExtensionArray,
_extension_array_shared_docs,
try_cast_to_ea,
)
from pandas.core.base import NoNewAttributesMixin, PandasObject, _shared_docs
import pandas.core.common as com
from pandas.core.construction import array, extract_array, sanitize_array
from pandas.core.indexers import check_array_indexer, deprecate_ndim_indexing
from pandas.core.missing import interpolate_2d
from pandas.core.ops.common import unpack_zerodim_and_defer
from pandas.core.sorting import nargsort
from pandas.io.formats import console
def _cat_compare_op(op):
opname = f"__{op.__name__}__"
@unpack_zerodim_and_defer(opname)
def func(self, other):
if is_list_like(other) and len(other) != len(self):
# TODO: Could this fail if the categories are listlike objects?
raise ValueError("Lengths must match.")
if not self.ordered:
if opname in ["__lt__", "__gt__", "__le__", "__ge__"]:
raise TypeError(
"Unordered Categoricals can only compare equality or not"
)
if isinstance(other, Categorical):
# Two Categoricals can only be be compared if the categories are
# the same (maybe up to ordering, depending on ordered)
msg = "Categoricals can only be compared if 'categories' are the same."
if len(self.categories) != len(other.categories):
raise TypeError(msg + " Categories are different lengths")
elif self.ordered and not (self.categories == other.categories).all():
raise TypeError(msg)
elif not set(self.categories) == set(other.categories):
raise TypeError(msg)
if not (self.ordered == other.ordered):
raise TypeError(
"Categoricals can only be compared if 'ordered' is the same"
)
if not self.ordered and not self.categories.equals(other.categories):
# both unordered and different order
other_codes = _get_codes_for_values(other, self.categories)
else:
other_codes = other._codes
f = getattr(self._codes, opname)
ret = f(other_codes)
mask = (self._codes == -1) | (other_codes == -1)
if mask.any():
# In other series, the leads to False, so do that here too
ret[mask] = False
return ret
if is_scalar(other):
if other in self.categories:
i = self.categories.get_loc(other)
ret = getattr(self._codes, opname)(i)
if opname not in {"__eq__", "__ge__", "__gt__"}:
# check for NaN needed if we are not equal or larger
mask = self._codes == -1
ret[mask] = False
return ret
else:
if opname == "__eq__":
return np.zeros(len(self), dtype=bool)
elif opname == "__ne__":
return np.ones(len(self), dtype=bool)
else:
raise TypeError(
f"Cannot compare a Categorical for op {opname} with a "
"scalar, which is not a category."
)
else:
# allow categorical vs object dtype array comparisons for equality
# these are only positional comparisons
if opname in ["__eq__", "__ne__"]:
return getattr(np.array(self), opname)(np.array(other))
raise TypeError(
f"Cannot compare a Categorical for op {opname} with "
f"type {type(other)}.\nIf you want to compare values, "
"use 'np.asarray(cat) <op> other'."
)
func.__name__ = opname
return func
def contains(cat, key, container):
"""
Helper for membership check for ``key`` in ``cat``.
This is a helper method for :method:`__contains__`
and :class:`CategoricalIndex.__contains__`.
Returns True if ``key`` is in ``cat.categories`` and the
location of ``key`` in ``categories`` is in ``container``.
Parameters
----------
cat : :class:`Categorical`or :class:`categoricalIndex`
key : a hashable object
The key to check membership for.
container : Container (e.g. list-like or mapping)
The container to check for membership in.
Returns
-------
is_in : bool
True if ``key`` is in ``self.categories`` and location of
``key`` in ``categories`` is in ``container``, else False.
Notes
-----
This method does not check for NaN values. Do that separately
before calling this method.
"""
hash(key)
# get location of key in categories.
# If a KeyError, the key isn't in categories, so logically
# can't be in container either.
try:
loc = cat.categories.get_loc(key)
except (KeyError, TypeError):
return False
# loc is the location of key in categories, but also the *value*
# for key in container. So, `key` may be in categories,
# but still not in `container`. Example ('b' in categories,
# but not in values):
# 'b' in Categorical(['a'], categories=['a', 'b']) # False
if is_scalar(loc):
return loc in container
else:
# if categories is an IntervalIndex, loc is an array.
return any(loc_ in container for loc_ in loc)
_codes_doc = """
The category codes of this categorical.
Level codes are an array if integer which are the positions of the real
values in the categories array.
There is not setter, use the other categorical methods and the normal item
setter to change values in the categorical.
"""
class Categorical(ExtensionArray, PandasObject):
"""
Represent a categorical variable in classic R / S-plus fashion.
`Categoricals` can only take on only a limited, and usually fixed, number
of possible values (`categories`). In contrast to statistical categorical
variables, a `Categorical` might have an order, but numerical operations
(additions, divisions, ...) are not possible.
All values of the `Categorical` are either in `categories` or `np.nan`.
Assigning values outside of `categories` will raise a `ValueError`. Order
is defined by the order of the `categories`, not lexical order of the
values.
Parameters
----------
values : list-like
The values of the categorical. If categories are given, values not in
categories will be replaced with NaN.
categories : Index-like (unique), optional
The unique categories for this categorical. If not given, the
categories are assumed to be the unique values of `values` (sorted, if
possible, otherwise in the order in which they appear).
ordered : bool, default False
Whether or not this categorical is treated as a ordered categorical.
If True, the resulting categorical will be ordered.
An ordered categorical respects, when sorted, the order of its
`categories` attribute (which in turn is the `categories` argument, if
provided).
dtype : CategoricalDtype
An instance of ``CategoricalDtype`` to use for this categorical.
.. versionadded:: 0.21.0
Attributes
----------
categories : Index
The categories of this categorical
codes : ndarray
The codes (integer positions, which point to the categories) of this
categorical, read only.
ordered : bool
Whether or not this Categorical is ordered.
dtype : CategoricalDtype
The instance of ``CategoricalDtype`` storing the ``categories``
and ``ordered``.
.. versionadded:: 0.21.0
Methods
-------
from_codes
__array__
Raises
------
ValueError
If the categories do not validate.
TypeError
If an explicit ``ordered=True`` is given but no `categories` and the
`values` are not sortable.
See Also
--------
CategoricalDtype : Type for categorical data.
CategoricalIndex : An Index with an underlying ``Categorical``.
Notes
-----
See the `user guide
<https://pandas.pydata.org/pandas-docs/stable/user_guide/categorical.html>`_
for more.
Examples
--------
>>> pd.Categorical([1, 2, 3, 1, 2, 3])
[1, 2, 3, 1, 2, 3]
Categories (3, int64): [1, 2, 3]
>>> pd.Categorical(['a', 'b', 'c', 'a', 'b', 'c'])
[a, b, c, a, b, c]
Categories (3, object): [a, b, c]
Ordered `Categoricals` can be sorted according to the custom order
of the categories and can have a min and max value.
>>> c = pd.Categorical(['a', 'b', 'c', 'a', 'b', 'c'], ordered=True,
... categories=['c', 'b', 'a'])
>>> c
[a, b, c, a, b, c]
Categories (3, object): [c < b < a]
>>> c.min()
'c'
"""
# For comparisons, so that numpy uses our implementation if the compare
# ops, which raise
__array_priority__ = 1000
_dtype = CategoricalDtype(ordered=False)
# tolist is not actually deprecated, just suppressed in the __dir__
_deprecations = PandasObject._deprecations | frozenset(["tolist"])
_typ = "categorical"
def __init__(
self, values, categories=None, ordered=None, dtype=None, fastpath=False
):
dtype = CategoricalDtype._from_values_or_dtype(
values, categories, ordered, dtype
)
# At this point, dtype is always a CategoricalDtype, but
# we may have dtype.categories be None, and we need to
# infer categories in a factorization step further below
if fastpath:
self._codes = coerce_indexer_dtype(values, dtype.categories)
self._dtype = self._dtype.update_dtype(dtype)
return
# null_mask indicates missing values we want to exclude from inference.
# This means: only missing values in list-likes (not arrays/ndframes).
null_mask = np.array(False)
# sanitize input
if is_categorical_dtype(values):
if dtype.categories is None:
dtype = CategoricalDtype(values.categories, dtype.ordered)
elif not isinstance(values, (ABCIndexClass, ABCSeries)):
# sanitize_array coerces np.nan to a string under certain versions
# of numpy
values = maybe_infer_to_datetimelike(values, convert_dates=True)
if not isinstance(values, np.ndarray):
values = _convert_to_list_like(values)
# By convention, empty lists result in object dtype:
if len(values) == 0:
sanitize_dtype = "object"
else:
sanitize_dtype = None
null_mask = isna(values)
if null_mask.any():
values = [values[idx] for idx in np.where(~null_mask)[0]]
values = sanitize_array(values, None, dtype=sanitize_dtype)
if dtype.categories is None:
try:
codes, categories = factorize(values, sort=True)
except TypeError:
codes, categories = factorize(values, sort=False)
if dtype.ordered:
# raise, as we don't have a sortable data structure and so
# the user should give us one by specifying categories
raise TypeError(
"'values' is not ordered, please "
"explicitly specify the categories order "
"by passing in a categories argument."
)
except ValueError:
# FIXME
raise NotImplementedError(
"> 1 ndim Categorical are not supported at this time"
)
# we're inferring from values
dtype = CategoricalDtype(categories, dtype.ordered)
elif is_categorical_dtype(values):
old_codes = (
values._values.codes if isinstance(values, ABCSeries) else values.codes
)
codes = _recode_for_categories(
old_codes, values.dtype.categories, dtype.categories
)
else:
codes = _get_codes_for_values(values, dtype.categories)
if null_mask.any():
# Reinsert -1 placeholders for previously removed missing values
full_codes = -np.ones(null_mask.shape, dtype=codes.dtype)
full_codes[~null_mask] = codes
codes = full_codes
self._dtype = self._dtype.update_dtype(dtype)
self._codes = coerce_indexer_dtype(codes, dtype.categories)
@property
def categories(self):
"""
The categories of this categorical.
Setting assigns new values to each category (effectively a rename of
each individual category).
The assigned value has to be a list-like object. All items must be
unique and the number of items in the new categories must be the same
as the number of items in the old categories.
Assigning to `categories` is a inplace operation!
Raises
------
ValueError
If the new categories do not validate as categories or if the
number of new categories is unequal the number of old categories
See Also
--------
rename_categories
reorder_categories
add_categories
remove_categories
remove_unused_categories
set_categories
"""
return self.dtype.categories
@categories.setter
def categories(self, categories):
new_dtype = CategoricalDtype(categories, ordered=self.ordered)
if self.dtype.categories is not None and len(self.dtype.categories) != len(
new_dtype.categories
):
raise ValueError(
"new categories need to have the same number of "
"items as the old categories!"
)
self._dtype = new_dtype
@property
def ordered(self) -> Ordered:
"""
Whether the categories have an ordered relationship.
"""
return self.dtype.ordered
@property
def dtype(self) -> CategoricalDtype:
"""
The :class:`~pandas.api.types.CategoricalDtype` for this instance.
"""
return self._dtype
@property
def _ndarray_values(self) -> np.ndarray:
return self.codes
@property
def _constructor(self) -> Type["Categorical"]:
return Categorical
@classmethod
def _from_sequence(cls, scalars, dtype=None, copy=False):
return Categorical(scalars, dtype=dtype)
def _formatter(self, boxed=False):
# Defer to CategoricalFormatter's formatter.
return None
def copy(self) -> "Categorical":
"""
Copy constructor.
"""
return self._constructor(
values=self._codes.copy(), dtype=self.dtype, fastpath=True
)
def astype(self, dtype: Dtype, copy: bool = True) -> ArrayLike:
"""
Coerce this type to another dtype
Parameters
----------
dtype : numpy dtype or pandas type
copy : bool, default True
By default, astype always returns a newly allocated object.
If copy is set to False and dtype is categorical, the original
object is returned.
"""
if is_categorical_dtype(dtype):
dtype = cast(Union[str, CategoricalDtype], dtype)
# GH 10696/18593
dtype = self.dtype.update_dtype(dtype)
self = self.copy() if copy else self
if dtype == self.dtype:
return self
return self._set_dtype(dtype)
if is_extension_array_dtype(dtype):
return array(self, dtype=dtype, copy=copy) # type: ignore # GH 28770
if is_integer_dtype(dtype) and self.isna().any():
raise ValueError("Cannot convert float NaN to integer")
return np.array(self, dtype=dtype, copy=copy)
@cache_readonly
def size(self) -> int:
"""
Return the len of myself.
"""
return self._codes.size
@cache_readonly
def itemsize(self) -> int:
"""
return the size of a single category
"""
return self.categories.itemsize
def tolist(self) -> List[Scalar]:
"""
Return a list of the values.
These are each a scalar type, which is a Python scalar
(for str, int, float) or a pandas scalar
(for Timestamp/Timedelta/Interval/Period)
"""
return list(self)
to_list = tolist
@classmethod
def _from_inferred_categories(
cls, inferred_categories, inferred_codes, dtype, true_values=None
):
"""
Construct a Categorical from inferred values.
For inferred categories (`dtype` is None) the categories are sorted.
For explicit `dtype`, the `inferred_categories` are cast to the
appropriate type.
Parameters
----------
inferred_categories : Index
inferred_codes : Index
dtype : CategoricalDtype or 'category'
true_values : list, optional
If none are provided, the default ones are
"True", "TRUE", and "true."
Returns
-------
Categorical
"""
from pandas import Index, to_numeric, to_datetime, to_timedelta
cats = Index(inferred_categories)
known_categories = (
isinstance(dtype, CategoricalDtype) and dtype.categories is not None
)
if known_categories:
# Convert to a specialized type with `dtype` if specified.
if dtype.categories.is_numeric():
cats = to_numeric(inferred_categories, errors="coerce")
elif is_datetime64_dtype(dtype.categories):
cats = to_datetime(inferred_categories, errors="coerce")
elif is_timedelta64_dtype(dtype.categories):
cats = to_timedelta(inferred_categories, errors="coerce")
elif dtype.categories.is_boolean():
if true_values is None:
true_values = ["True", "TRUE", "true"]
cats = cats.isin(true_values)
if known_categories:
# Recode from observation order to dtype.categories order.
categories = dtype.categories
codes = _recode_for_categories(inferred_codes, cats, categories)
elif not cats.is_monotonic_increasing:
# Sort categories and recode for unknown categories.
unsorted = cats.copy()
categories = cats.sort_values()
codes = _recode_for_categories(inferred_codes, unsorted, categories)
dtype = CategoricalDtype(categories, ordered=False)
else:
dtype = CategoricalDtype(cats, ordered=False)
codes = inferred_codes
return cls(codes, dtype=dtype, fastpath=True)
@classmethod
def from_codes(cls, codes, categories=None, ordered=None, dtype=None):
"""
Make a Categorical type from codes and categories or dtype.
This constructor is useful if you already have codes and
categories/dtype and so do not need the (computation intensive)
factorization step, which is usually done on the constructor.
If your data does not follow this convention, please use the normal
constructor.
Parameters
----------
codes : array-like of int
An integer array, where each integer points to a category in
categories or dtype.categories, or else is -1 for NaN.
categories : index-like, optional
The categories for the categorical. Items need to be unique.
If the categories are not given here, then they must be provided
in `dtype`.
ordered : bool, optional
Whether or not this categorical is treated as an ordered
categorical. If not given here or in `dtype`, the resulting
categorical will be unordered.
dtype : CategoricalDtype or "category", optional
If :class:`CategoricalDtype`, cannot be used together with
`categories` or `ordered`.
.. versionadded:: 0.24.0
When `dtype` is provided, neither `categories` nor `ordered`
should be provided.
Returns
-------
Categorical
Examples
--------
>>> dtype = pd.CategoricalDtype(['a', 'b'], ordered=True)
>>> pd.Categorical.from_codes(codes=[0, 1, 0, 1], dtype=dtype)
[a, b, a, b]
Categories (2, object): [a < b]
"""
dtype = CategoricalDtype._from_values_or_dtype(
categories=categories, ordered=ordered, dtype=dtype
)
if dtype.categories is None:
msg = (
"The categories must be provided in 'categories' or "
"'dtype'. Both were None."
)
raise ValueError(msg)
if is_extension_array_dtype(codes) and is_integer_dtype(codes):
# Avoid the implicit conversion of Int to object
if isna(codes).any():
raise ValueError("codes cannot contain NA values")
codes = codes.to_numpy(dtype=np.int64)
else:
codes = np.asarray(codes)
if len(codes) and not is_integer_dtype(codes):
raise ValueError("codes need to be array-like integers")
if len(codes) and (codes.max() >= len(dtype.categories) or codes.min() < -1):
raise ValueError("codes need to be between -1 and len(categories)-1")
return cls(codes, dtype=dtype, fastpath=True)
def _get_codes(self):
"""
Get the codes.
Returns
-------
codes : integer array view
A non writable view of the `codes` array.
"""
v = self._codes.view()
v.flags.writeable = False
return v
def _set_codes(self, codes):
"""
Not settable by the user directly
"""
raise ValueError("cannot set Categorical codes directly")
codes = property(fget=_get_codes, fset=_set_codes, doc=_codes_doc)
def _set_categories(self, categories, fastpath=False):
"""
Sets new categories inplace
Parameters
----------
fastpath : bool, default False
Don't perform validation of the categories for uniqueness or nulls
Examples
--------
>>> c = pd.Categorical(['a', 'b'])
>>> c
[a, b]
Categories (2, object): [a, b]
>>> c._set_categories(pd.Index(['a', 'c']))
>>> c
[a, c]
Categories (2, object): [a, c]
"""
if fastpath:
new_dtype = CategoricalDtype._from_fastpath(categories, self.ordered)
else:
new_dtype = CategoricalDtype(categories, ordered=self.ordered)
if (
not fastpath
and self.dtype.categories is not None
and len(new_dtype.categories) != len(self.dtype.categories)
):
raise ValueError(
"new categories need to have the same number of "
"items than the old categories!"
)
self._dtype = new_dtype
def _set_dtype(self, dtype: CategoricalDtype) -> "Categorical":
"""
Internal method for directly updating the CategoricalDtype
Parameters
----------
dtype : CategoricalDtype
Notes
-----
We don't do any validation here. It's assumed that the dtype is
a (valid) instance of `CategoricalDtype`.
"""
codes = _recode_for_categories(self.codes, self.categories, dtype.categories)
return type(self)(codes, dtype=dtype, fastpath=True)
def set_ordered(self, value, inplace=False):
"""
Set the ordered attribute to the boolean value.
Parameters
----------
value : bool
Set whether this categorical is ordered (True) or not (False).
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to the value.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
new_dtype = CategoricalDtype(self.categories, ordered=value)
cat = self if inplace else self.copy()
cat._dtype = new_dtype
if not inplace:
return cat
def as_ordered(self, inplace=False):
"""
Set the Categorical to be ordered.
Parameters
----------
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to True.
Returns
-------
Categorical
Ordered Categorical.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
return self.set_ordered(True, inplace=inplace)
def as_unordered(self, inplace=False):
"""
Set the Categorical to be unordered.
Parameters
----------
inplace : bool, default False
Whether or not to set the ordered attribute in-place or return
a copy of this categorical with ordered set to False.
Returns
-------
Categorical
Unordered Categorical.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
return self.set_ordered(False, inplace=inplace)
def set_categories(self, new_categories, ordered=None, rename=False, inplace=False):
"""
Set the categories to the specified new_categories.
`new_categories` can include new categories (which will result in
unused categories) or remove old categories (which results in values
set to NaN). If `rename==True`, the categories will simple be renamed
(less or more items than in old categories will result in values set to
NaN or in unused categories respectively).
This method can be used to perform more than one action of adding,
removing, and reordering simultaneously and is therefore faster than
performing the individual steps via the more specialised methods.
On the other hand this methods does not do checks (e.g., whether the
old categories are included in the new categories on a reorder), which
can result in surprising changes, for example when using special string
dtypes, which does not considers a S1 string equal to a single char
python string.
Parameters
----------
new_categories : Index-like
The categories in new order.
ordered : bool, default False
Whether or not the categorical is treated as a ordered categorical.
If not given, do not change the ordered information.
rename : bool, default False
Whether or not the new_categories should be considered as a rename
of the old categories or as reordered categories.
inplace : bool, default False
Whether or not to reorder the categories in-place or return a copy
of this categorical with reordered categories.
Returns
-------
Categorical with reordered categories or None if inplace.
Raises
------
ValueError
If new_categories does not validate as categories
See Also
--------
rename_categories
reorder_categories
add_categories
remove_categories
remove_unused_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if ordered is None:
ordered = self.dtype.ordered
new_dtype = CategoricalDtype(new_categories, ordered=ordered)
cat = self if inplace else self.copy()
if rename:
if cat.dtype.categories is not None and len(new_dtype.categories) < len(
cat.dtype.categories
):
# remove all _codes which are larger and set to -1/NaN
cat._codes[cat._codes >= len(new_dtype.categories)] = -1
else:
codes = _recode_for_categories(
cat.codes, cat.categories, new_dtype.categories
)
cat._codes = codes
cat._dtype = new_dtype
if not inplace:
return cat
def rename_categories(self, new_categories, inplace=False):
"""
Rename categories.
Parameters
----------
new_categories : list-like, dict-like or callable
New categories which will replace old categories.
* list-like: all items must be unique and the number of items in
the new categories must match the existing number of categories.
* dict-like: specifies a mapping from
old categories to new. Categories not contained in the mapping
are passed through and extra categories in the mapping are
ignored.
.. versionadded:: 0.21.0.
* callable : a callable that is called on all items in the old
categories and whose return values comprise the new categories.
.. versionadded:: 0.23.0.
inplace : bool, default False
Whether or not to rename the categories inplace or return a copy of
this categorical with renamed categories.
Returns
-------
cat : Categorical or None
With ``inplace=False``, the new categorical is returned.
With ``inplace=True``, there is no return value.
Raises
------
ValueError
If new categories are list-like and do not have the same number of
items than the current categories or do not validate as categories
See Also
--------
reorder_categories
add_categories
remove_categories
remove_unused_categories
set_categories
Examples
--------
>>> c = pd.Categorical(['a', 'a', 'b'])
>>> c.rename_categories([0, 1])
[0, 0, 1]
Categories (2, int64): [0, 1]
For dict-like ``new_categories``, extra keys are ignored and
categories not in the dictionary are passed through
>>> c.rename_categories({'a': 'A', 'c': 'C'})
[A, A, b]
Categories (2, object): [A, b]
You may also provide a callable to create the new categories
>>> c.rename_categories(lambda x: x.upper())
[A, A, B]
Categories (2, object): [A, B]
"""
inplace = validate_bool_kwarg(inplace, "inplace")
cat = self if inplace else self.copy()
if is_dict_like(new_categories):
cat.categories = [new_categories.get(item, item) for item in cat.categories]
elif callable(new_categories):
cat.categories = [new_categories(item) for item in cat.categories]
else:
cat.categories = new_categories
if not inplace:
return cat
def reorder_categories(self, new_categories, ordered=None, inplace=False):
"""
Reorder categories as specified in new_categories.
`new_categories` need to include all old categories and no new category
items.
Parameters
----------
new_categories : Index-like
The categories in new order.
ordered : bool, optional
Whether or not the categorical is treated as a ordered categorical.
If not given, do not change the ordered information.
inplace : bool, default False
Whether or not to reorder the categories inplace or return a copy of
this categorical with reordered categories.
Returns
-------
cat : Categorical with reordered categories or None if inplace.
Raises
------
ValueError
If the new categories do not contain all old category items or any
new ones
See Also
--------
rename_categories
add_categories
remove_categories
remove_unused_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if set(self.dtype.categories) != set(new_categories):
raise ValueError(
"items in new_categories are not the same as in old categories"
)
return self.set_categories(new_categories, ordered=ordered, inplace=inplace)
def add_categories(self, new_categories, inplace=False):
"""
Add new categories.
`new_categories` will be included at the last/highest place in the
categories and will be unused directly after this call.
Parameters
----------
new_categories : category or list-like of category
The new categories to be included.
inplace : bool, default False
Whether or not to add the categories inplace or return a copy of
this categorical with added categories.
Returns
-------
cat : Categorical with new categories added or None if inplace.
Raises
------
ValueError
If the new categories include old categories or do not validate as
categories
See Also
--------
rename_categories
reorder_categories
remove_categories
remove_unused_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not is_list_like(new_categories):
new_categories = [new_categories]
already_included = set(new_categories) & set(self.dtype.categories)
if len(already_included) != 0:
raise ValueError(
f"new categories must not include old categories: {already_included}"
)
new_categories = list(self.dtype.categories) + list(new_categories)
new_dtype = CategoricalDtype(new_categories, self.ordered)
cat = self if inplace else self.copy()
cat._dtype = new_dtype
cat._codes = coerce_indexer_dtype(cat._codes, new_dtype.categories)
if not inplace:
return cat
def remove_categories(self, removals, inplace=False):
"""
Remove the specified categories.
`removals` must be included in the old categories. Values which were in
the removed categories will be set to NaN
Parameters
----------
removals : category or list of categories
The categories which should be removed.
inplace : bool, default False
Whether or not to remove the categories inplace or return a copy of
this categorical with removed categories.
Returns
-------
cat : Categorical with removed categories or None if inplace.
Raises
------
ValueError
If the removals are not contained in the categories
See Also
--------
rename_categories
reorder_categories
add_categories
remove_unused_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not is_list_like(removals):
removals = [removals]
removal_set = set(removals)
not_included = removal_set - set(self.dtype.categories)
new_categories = [c for c in self.dtype.categories if c not in removal_set]
# GH 10156
if any(isna(removals)):
not_included = {x for x in not_included if notna(x)}
new_categories = [x for x in new_categories if notna(x)]
if len(not_included) != 0:
raise ValueError(f"removals must all be in old categories: {not_included}")
return self.set_categories(
new_categories, ordered=self.ordered, rename=False, inplace=inplace
)
def remove_unused_categories(self, inplace=False):
"""
Remove categories which are not used.
Parameters
----------
inplace : bool, default False
Whether or not to drop unused categories inplace or return a copy of
this categorical with unused categories dropped.
Returns
-------
cat : Categorical with unused categories dropped or None if inplace.
See Also
--------
rename_categories
reorder_categories
add_categories
remove_categories
set_categories
"""
inplace = validate_bool_kwarg(inplace, "inplace")
cat = self if inplace else self.copy()
idx, inv = np.unique(cat._codes, return_inverse=True)
if idx.size != 0 and idx[0] == -1: # na sentinel
idx, inv = idx[1:], inv - 1
new_categories = cat.dtype.categories.take(idx)
new_dtype = CategoricalDtype._from_fastpath(
new_categories, ordered=self.ordered
)
cat._dtype = new_dtype
cat._codes = coerce_indexer_dtype(inv, new_dtype.categories)
if not inplace:
return cat
def map(self, mapper):
"""
Map categories using input correspondence (dict, Series, or function).
Maps the categories to new categories. If the mapping correspondence is
one-to-one the result is a :class:`~pandas.Categorical` which has the
same order property as the original, otherwise a :class:`~pandas.Index`
is returned. NaN values are unaffected.
If a `dict` or :class:`~pandas.Series` is used any unmapped category is
mapped to `NaN`. Note that if this happens an :class:`~pandas.Index`
will be returned.
Parameters
----------
mapper : function, dict, or Series
Mapping correspondence.
Returns
-------
pandas.Categorical or pandas.Index
Mapped categorical.
See Also
--------
CategoricalIndex.map : Apply a mapping correspondence on a
:class:`~pandas.CategoricalIndex`.
Index.map : Apply a mapping correspondence on an
:class:`~pandas.Index`.
Series.map : Apply a mapping correspondence on a
:class:`~pandas.Series`.
Series.apply : Apply more complex functions on a
:class:`~pandas.Series`.
Examples
--------
>>> cat = pd.Categorical(['a', 'b', 'c'])
>>> cat
[a, b, c]
Categories (3, object): [a, b, c]
>>> cat.map(lambda x: x.upper())
[A, B, C]
Categories (3, object): [A, B, C]
>>> cat.map({'a': 'first', 'b': 'second', 'c': 'third'})
[first, second, third]
Categories (3, object): [first, second, third]
If the mapping is one-to-one the ordering of the categories is
preserved:
>>> cat = pd.Categorical(['a', 'b', 'c'], ordered=True)
>>> cat
[a, b, c]
Categories (3, object): [a < b < c]
>>> cat.map({'a': 3, 'b': 2, 'c': 1})
[3, 2, 1]
Categories (3, int64): [3 < 2 < 1]
If the mapping is not one-to-one an :class:`~pandas.Index` is returned:
>>> cat.map({'a': 'first', 'b': 'second', 'c': 'first'})
Index(['first', 'second', 'first'], dtype='object')
If a `dict` is used, all unmapped categories are mapped to `NaN` and
the result is an :class:`~pandas.Index`:
>>> cat.map({'a': 'first', 'b': 'second'})
Index(['first', 'second', nan], dtype='object')
"""
new_categories = self.categories.map(mapper)
try:
return self.from_codes(
self._codes.copy(), categories=new_categories, ordered=self.ordered
)
except ValueError:
# NA values are represented in self._codes with -1
# np.take causes NA values to take final element in new_categories
if np.any(self._codes == -1):
new_categories = new_categories.insert(len(new_categories), np.nan)
return np.take(new_categories, self._codes)
__eq__ = _cat_compare_op(operator.eq)
__ne__ = _cat_compare_op(operator.ne)
__lt__ = _cat_compare_op(operator.lt)
__gt__ = _cat_compare_op(operator.gt)
__le__ = _cat_compare_op(operator.le)
__ge__ = _cat_compare_op(operator.ge)
# for Series/ndarray like compat
@property
def shape(self):
"""
Shape of the Categorical.
For internal compatibility with numpy arrays.
Returns
-------
shape : tuple
"""
return tuple([len(self._codes)])
def shift(self, periods, fill_value=None):
"""
Shift Categorical by desired number of periods.
Parameters
----------
periods : int
Number of periods to move, can be positive or negative
fill_value : object, optional
The scalar value to use for newly introduced missing values.
.. versionadded:: 0.24.0
Returns
-------
shifted : Categorical
"""
# since categoricals always have ndim == 1, an axis parameter
# doesn't make any sense here.
codes = self.codes
if codes.ndim > 1:
raise NotImplementedError("Categorical with ndim > 1.")
if np.prod(codes.shape) and (periods != 0):
codes = np.roll(codes, ensure_platform_int(periods), axis=0)
if isna(fill_value):
fill_value = -1
elif fill_value in self.categories:
fill_value = self.categories.get_loc(fill_value)
else:
raise ValueError(
f"'fill_value={fill_value}' is not present "
"in this Categorical's categories"
)
if periods > 0:
codes[:periods] = fill_value
else:
codes[periods:] = fill_value
return self.from_codes(codes, dtype=self.dtype)
def __array__(self, dtype=None) -> np.ndarray:
"""
The numpy array interface.
Returns
-------
numpy.array
A numpy array of either the specified dtype or,
if dtype==None (default), the same dtype as
categorical.categories.dtype.
"""
ret = take_1d(self.categories.values, self._codes)
if dtype and not is_dtype_equal(dtype, self.categories.dtype):
return np.asarray(ret, dtype)
if is_extension_array_dtype(ret):
# When we're a Categorical[ExtensionArray], like Interval,
# we need to ensure __array__ get's all the way to an
# ndarray.
ret = np.asarray(ret)
return ret
def __array_ufunc__(self, ufunc, method, *inputs, **kwargs):
# for binary ops, use our custom dunder methods
result = ops.maybe_dispatch_ufunc_to_dunder_op(
self, ufunc, method, *inputs, **kwargs
)
if result is not NotImplemented:
return result
# for all other cases, raise for now (similarly as what happens in
# Series.__array_prepare__)
raise TypeError(
f"Object with dtype {self.dtype} cannot perform "
f"the numpy op {ufunc.__name__}"
)
def __setstate__(self, state):
"""Necessary for making this object picklable"""
if not isinstance(state, dict):
raise Exception("invalid pickle state")
# compat with pre 0.21.0 CategoricalDtype change
if "_dtype" not in state:
state["_dtype"] = CategoricalDtype(state["_categories"], state["_ordered"])
for k, v in state.items():
setattr(self, k, v)
@property
def T(self):
"""
Return transposed numpy array.
"""
return self
@property
def nbytes(self):
return self._codes.nbytes + self.dtype.categories.values.nbytes
def memory_usage(self, deep=False):
"""
Memory usage of my values
Parameters
----------
deep : bool
Introspect the data deeply, interrogate
`object` dtypes for system-level memory consumption
Returns
-------
bytes used
Notes
-----
Memory usage does not include memory consumed by elements that
are not components of the array if deep=False
See Also
--------
numpy.ndarray.nbytes
"""
return self._codes.nbytes + self.dtype.categories.memory_usage(deep=deep)
@Substitution(klass="Categorical")
@Appender(_shared_docs["searchsorted"])
def searchsorted(self, value, side="left", sorter=None):
# searchsorted is very performance sensitive. By converting codes
# to same dtype as self.codes, we get much faster performance.
if is_scalar(value):
codes = self.categories.get_loc(value)
codes = self.codes.dtype.type(codes)
else:
locs = [self.categories.get_loc(x) for x in value]
codes = np.array(locs, dtype=self.codes.dtype)
return self.codes.searchsorted(codes, side=side, sorter=sorter)
def isna(self):
"""
Detect missing values
Missing values (-1 in .codes) are detected.
Returns
-------
a boolean array of whether my values are null
See Also
--------
isna : Top-level isna.
isnull : Alias of isna.
Categorical.notna : Boolean inverse of Categorical.isna.
"""
ret = self._codes == -1
return ret
isnull = isna
def notna(self):
"""
Inverse of isna
Both missing values (-1 in .codes) and NA as a category are detected as
null.
Returns
-------
a boolean array of whether my values are not null
See Also
--------
notna : Top-level notna.
notnull : Alias of notna.
Categorical.isna : Boolean inverse of Categorical.notna.
"""
return ~self.isna()
notnull = notna
def put(self, *args, **kwargs):
"""
Replace specific elements in the Categorical with given values.
"""
raise NotImplementedError(("'put' is not yet implemented for Categorical"))
def dropna(self):
"""
Return the Categorical without null values.
Missing values (-1 in .codes) are detected.
Returns
-------
valid : Categorical
"""
result = self[self.notna()]
return result
def value_counts(self, dropna=True):
"""
Return a Series containing counts of each category.
Every category will have an entry, even those with a count of 0.
Parameters
----------
dropna : bool, default True
Don't include counts of NaN.
Returns
-------
counts : Series
See Also
--------
Series.value_counts
"""
from pandas import Series, CategoricalIndex
code, cat = self._codes, self.categories
ncat, mask = len(cat), 0 <= code
ix, clean = np.arange(ncat), mask.all()
if dropna or clean:
obs = code if clean else code[mask]
count = np.bincount(obs, minlength=ncat or 0)
else:
count = np.bincount(np.where(mask, code, ncat))
ix = np.append(ix, -1)
ix = self._constructor(ix, dtype=self.dtype, fastpath=True)
return Series(count, index=CategoricalIndex(ix), dtype="int64")
def _internal_get_values(self):
"""
Return the values.
For internal compatibility with pandas formatting.
Returns
-------
np.ndarray or Index
A numpy array of the same dtype as categorical.categories.dtype or
Index if datetime / periods.
"""
# if we are a datetime and period index, return Index to keep metadata
if needs_i8_conversion(self.categories):
return self.categories.take(self._codes, fill_value=np.nan)
elif is_integer_dtype(self.categories) and -1 in self._codes:
return self.categories.astype("object").take(self._codes, fill_value=np.nan)
return np.array(self)
def check_for_ordered(self, op):
""" assert that we are ordered """
if not self.ordered:
raise TypeError(
f"Categorical is not ordered for operation {op}\n"
"you can use .as_ordered() to change the "
"Categorical to an ordered one\n"
)
def _values_for_argsort(self):
return self._codes.copy()
def argsort(self, ascending=True, kind="quicksort", *args, **kwargs):
"""
Return the indices that would sort the Categorical.
.. versionchanged:: 0.25.0
Changed to sort missing values at the end.
Parameters
----------
ascending : bool, default True
Whether the indices should result in an ascending
or descending sort.
kind : {'quicksort', 'mergesort', 'heapsort'}, optional
Sorting algorithm.
*args, **kwargs:
passed through to :func:`numpy.argsort`.
Returns
-------
numpy.array
See Also
--------
numpy.ndarray.argsort
Notes
-----
While an ordering is applied to the category values, arg-sorting
in this context refers more to organizing and grouping together
based on matching category values. Thus, this function can be
called on an unordered Categorical instance unlike the functions
'Categorical.min' and 'Categorical.max'.
Examples
--------
>>> pd.Categorical(['b', 'b', 'a', 'c']).argsort()
array([2, 0, 1, 3])
>>> cat = pd.Categorical(['b', 'b', 'a', 'c'],
... categories=['c', 'b', 'a'],
... ordered=True)
>>> cat.argsort()
array([3, 0, 1, 2])
Missing values are placed at the end
>>> cat = pd.Categorical([2, None, 1])
>>> cat.argsort()
array([2, 0, 1])
"""
return super().argsort(ascending=ascending, kind=kind, *args, **kwargs)
def sort_values(self, inplace=False, ascending=True, na_position="last"):
"""
Sort the Categorical by category value returning a new
Categorical by default.
While an ordering is applied to the category values, sorting in this
context refers more to organizing and grouping together based on
matching category values. Thus, this function can be called on an
unordered Categorical instance unlike the functions 'Categorical.min'
and 'Categorical.max'.
Parameters
----------
inplace : bool, default False
Do operation in place.
ascending : bool, default True
Order ascending. Passing False orders descending. The
ordering parameter provides the method by which the
category values are organized.
na_position : {'first', 'last'} (optional, default='last')
'first' puts NaNs at the beginning
'last' puts NaNs at the end
Returns
-------
Categorical or None
See Also
--------
Categorical.sort
Series.sort_values
Examples
--------
>>> c = pd.Categorical([1, 2, 2, 1, 5])
>>> c
[1, 2, 2, 1, 5]
Categories (3, int64): [1, 2, 5]
>>> c.sort_values()
[1, 1, 2, 2, 5]
Categories (3, int64): [1, 2, 5]
>>> c.sort_values(ascending=False)
[5, 2, 2, 1, 1]
Categories (3, int64): [1, 2, 5]
Inplace sorting can be done as well:
>>> c.sort_values(inplace=True)
>>> c
[1, 1, 2, 2, 5]
Categories (3, int64): [1, 2, 5]
>>>
>>> c = pd.Categorical([1, 2, 2, 1, 5])
'sort_values' behaviour with NaNs. Note that 'na_position'
is independent of the 'ascending' parameter:
>>> c = pd.Categorical([np.nan, 2, 2, np.nan, 5])
>>> c
[NaN, 2.0, 2.0, NaN, 5.0]
Categories (2, int64): [2, 5]
>>> c.sort_values()
[2.0, 2.0, 5.0, NaN, NaN]
Categories (2, int64): [2, 5]
>>> c.sort_values(ascending=False)
[5.0, 2.0, 2.0, NaN, NaN]
Categories (2, int64): [2, 5]
>>> c.sort_values(na_position='first')
[NaN, NaN, 2.0, 2.0, 5.0]
Categories (2, int64): [2, 5]
>>> c.sort_values(ascending=False, na_position='first')
[NaN, NaN, 5.0, 2.0, 2.0]
Categories (2, int64): [2, 5]
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if na_position not in ["last", "first"]:
raise ValueError(f"invalid na_position: {repr(na_position)}")
sorted_idx = nargsort(self, ascending=ascending, na_position=na_position)
if inplace:
self._codes = self._codes[sorted_idx]
else:
return self._constructor(
values=self._codes[sorted_idx], dtype=self.dtype, fastpath=True
)
def _values_for_rank(self):
"""
For correctly ranking ordered categorical data. See GH#15420
Ordered categorical data should be ranked on the basis of
codes with -1 translated to NaN.
Returns
-------
numpy.array
"""
from pandas import Series
if self.ordered:
values = self.codes
mask = values == -1
if mask.any():
values = values.astype("float64")
values[mask] = np.nan
elif self.categories.is_numeric():
values = np.array(self)
else:
# reorder the categories (so rank can use the float codes)
# instead of passing an object array to rank
values = np.array(
self.rename_categories(Series(self.categories).rank().values)
)
return values
def view(self, dtype=None):
if dtype is not None:
raise NotImplementedError(dtype)
return self._constructor(values=self._codes, dtype=self.dtype, fastpath=True)
def to_dense(self):
"""
Return my 'dense' representation
For internal compatibility with numpy arrays.
Returns
-------
dense : array
"""
return np.asarray(self)
def fillna(self, value=None, method=None, limit=None):
"""
Fill NA/NaN values using the specified method.
Parameters
----------
value : scalar, dict, Series
If a scalar value is passed it is used to fill all missing values.
Alternatively, a Series or dict can be used to fill in different
values for each index. The value should not be a list. The
value(s) passed should either be in the categories or should be
NaN.
method : {'backfill', 'bfill', 'pad', 'ffill', None}, default None
Method to use for filling holes in reindexed Series
pad / ffill: propagate last valid observation forward to next valid
backfill / bfill: use NEXT valid observation to fill gap
limit : int, default None
(Not implemented yet for Categorical!)
If method is specified, this is the maximum number of consecutive
NaN values to forward/backward fill. In other words, if there is
a gap with more than this number of consecutive NaNs, it will only
be partially filled. If method is not specified, this is the
maximum number of entries along the entire axis where NaNs will be
filled.
Returns
-------
filled : Categorical with NA/NaN filled
"""
value, method = validate_fillna_kwargs(
value, method, validate_scalar_dict_value=False
)
if value is None:
value = np.nan
if limit is not None:
raise NotImplementedError(
"specifying a limit for fillna has not been implemented yet"
)
codes = self._codes
# pad / bfill
if method is not None:
values = self.to_dense().reshape(-1, len(self))
values = interpolate_2d(values, method, 0, None, value).astype(
self.categories.dtype
)[0]
codes = _get_codes_for_values(values, self.categories)
else:
# If value is a dict or a Series (a dict value has already
# been converted to a Series)
if isinstance(value, ABCSeries):
if not value[~value.isin(self.categories)].isna().all():
raise ValueError("fill value must be in categories")
values_codes = _get_codes_for_values(value, self.categories)
indexer = np.where(codes == -1)
codes[indexer] = values_codes[indexer]
# If value is not a dict or Series it should be a scalar
elif is_hashable(value):
if not isna(value) and value not in self.categories:
raise ValueError("fill value must be in categories")
mask = codes == -1
if mask.any():
codes = codes.copy()
if isna(value):
codes[mask] = -1
else:
codes[mask] = self.categories.get_loc(value)
else:
raise TypeError(
f"'value' parameter must be a scalar, dict "
f"or Series, but you passed a {type(value).__name__}"
)
return self._constructor(codes, dtype=self.dtype, fastpath=True)
def take(self, indexer, allow_fill: bool = False, fill_value=None):
"""
Take elements from the Categorical.
Parameters
----------
indexer : sequence of int
The indices in `self` to take. The meaning of negative values in
`indexer` depends on the value of `allow_fill`.
allow_fill : bool, default False
How to handle negative values in `indexer`.
* False: negative values in `indices` indicate positional indices
from the right. This is similar to
:func:`numpy.take`.
* True: negative values in `indices` indicate missing values
(the default). These values are set to `fill_value`. Any other
other negative values raise a ``ValueError``.
.. versionchanged:: 1.0.0
Default value changed from ``True`` to ``False``.
fill_value : object
The value to use for `indices` that are missing (-1), when
``allow_fill=True``. This should be the category, i.e. a value
in ``self.categories``, not a code.
Returns
-------
Categorical
This Categorical will have the same categories and ordered as
`self`.
See Also
--------
Series.take : Similar method for Series.
numpy.ndarray.take : Similar method for NumPy arrays.
Examples
--------
>>> cat = pd.Categorical(['a', 'a', 'b'])
>>> cat
[a, a, b]
Categories (2, object): [a, b]
Specify ``allow_fill==False`` to have negative indices mean indexing
from the right.
>>> cat.take([0, -1, -2], allow_fill=False)
[a, b, a]
Categories (2, object): [a, b]
With ``allow_fill=True``, indices equal to ``-1`` mean "missing"
values that should be filled with the `fill_value`, which is
``np.nan`` by default.
>>> cat.take([0, -1, -1], allow_fill=True)
[a, NaN, NaN]
Categories (2, object): [a, b]
The fill value can be specified.
>>> cat.take([0, -1, -1], allow_fill=True, fill_value='a')
[a, a, a]
Categories (3, object): [a, b]
Specifying a fill value that's not in ``self.categories``
will raise a ``TypeError``.
"""
indexer = np.asarray(indexer, dtype=np.intp)
dtype = self.dtype
if isna(fill_value):
fill_value = -1
elif allow_fill:
# convert user-provided `fill_value` to codes
if fill_value in self.categories:
fill_value = self.categories.get_loc(fill_value)
else:
msg = (
f"'fill_value' ('{fill_value}') is not in this "
"Categorical's categories."
)
raise TypeError(msg)
codes = take(self._codes, indexer, allow_fill=allow_fill, fill_value=fill_value)
result = type(self).from_codes(codes, dtype=dtype)
return result
def take_nd(self, indexer, allow_fill: bool = False, fill_value=None):
# GH#27745 deprecate alias that other EAs dont have
warn(
"Categorical.take_nd is deprecated, use Categorical.take instead",
FutureWarning,
stacklevel=2,
)
return self.take(indexer, allow_fill=allow_fill, fill_value=fill_value)
def __len__(self) -> int:
"""
The length of this Categorical.
"""
return len(self._codes)
def __iter__(self):
"""
Returns an Iterator over the values of this Categorical.
"""
return iter(self._internal_get_values().tolist())
def __contains__(self, key) -> bool:
"""
Returns True if `key` is in this Categorical.
"""
# if key is a NaN, check if any NaN is in self.
if is_scalar(key) and isna(key):
return self.isna().any()
return contains(self, key, container=self._codes)
def _tidy_repr(self, max_vals=10, footer=True) -> str:
""" a short repr displaying only max_vals and an optional (but default
footer)
"""
num = max_vals // 2
head = self[:num]._get_repr(length=False, footer=False)
tail = self[-(max_vals - num) :]._get_repr(length=False, footer=False)
result = f"{head[:-1]}, ..., {tail[1:]}"
if footer:
result = f"{result}\n{self._repr_footer()}"
return str(result)
def _repr_categories(self):
"""
return the base repr for the categories
"""
max_categories = (
10
if get_option("display.max_categories") == 0
else get_option("display.max_categories")
)
from pandas.io.formats import format as fmt
if len(self.categories) > max_categories:
num = max_categories // 2
head = fmt.format_array(self.categories[:num], None)
tail = fmt.format_array(self.categories[-num:], None)
category_strs = head + ["..."] + tail
else:
category_strs = fmt.format_array(self.categories, None)
# Strip all leading spaces, which format_array adds for columns...
category_strs = [x.strip() for x in category_strs]
return category_strs
def _repr_categories_info(self) -> str:
"""
Returns a string representation of the footer.
"""
category_strs = self._repr_categories()
dtype = str(self.categories.dtype)
levheader = f"Categories ({len(self.categories)}, {dtype}): "
width, height = get_terminal_size()
max_width = get_option("display.width") or width
if console.in_ipython_frontend():
# 0 = no breaks
max_width = 0
levstring = ""
start = True
cur_col_len = len(levheader) # header
sep_len, sep = (3, " < ") if self.ordered else (2, ", ")
linesep = sep.rstrip() + "\n" # remove whitespace
for val in category_strs:
if max_width != 0 and cur_col_len + sep_len + len(val) > max_width:
levstring += linesep + (" " * (len(levheader) + 1))
cur_col_len = len(levheader) + 1 # header + a whitespace
elif not start:
levstring += sep
cur_col_len += len(val)
levstring += val
start = False
# replace to simple save space by
return levheader + "[" + levstring.replace(" < ... < ", " ... ") + "]"
def _repr_footer(self) -> str:
info = self._repr_categories_info()
return f"Length: {len(self)}\n{info}"
def _get_repr(self, length=True, na_rep="NaN", footer=True) -> str:
from pandas.io.formats import format as fmt
formatter = fmt.CategoricalFormatter(
self, length=length, na_rep=na_rep, footer=footer
)
result = formatter.to_string()
return str(result)
def __repr__(self) -> str:
"""
String representation.
"""
_maxlen = 10
if len(self._codes) > _maxlen:
result = self._tidy_repr(_maxlen)
elif len(self._codes) > 0:
result = self._get_repr(length=len(self) > _maxlen)
else:
msg = self._get_repr(length=False, footer=True).replace("\n", ", ")
result = f"[], {msg}"
return result
def _maybe_coerce_indexer(self, indexer):
"""
return an indexer coerced to the codes dtype
"""
if isinstance(indexer, np.ndarray) and indexer.dtype.kind == "i":
indexer = indexer.astype(self._codes.dtype)
return indexer
def __getitem__(self, key):
"""
Return an item.
"""
if isinstance(key, (int, np.integer)):
i = self._codes[key]
if i == -1:
return np.nan
else:
return self.categories[i]
key = check_array_indexer(self, key)
result = self._codes[key]
if result.ndim > 1:
deprecate_ndim_indexing(result)
return result
return self._constructor(result, dtype=self.dtype, fastpath=True)
def __setitem__(self, key, value):
"""
Item assignment.
Raises
------
ValueError
If (one or more) Value is not in categories or if a assigned
`Categorical` does not have the same categories
"""
value = extract_array(value, extract_numpy=True)
# require identical categories set
if isinstance(value, Categorical):
if not is_dtype_equal(self, value):
raise ValueError(
"Cannot set a Categorical with another, "
"without identical categories"
)
if not self.categories.equals(value.categories):
new_codes = _recode_for_categories(
value.codes, value.categories, self.categories
)
value = Categorical.from_codes(new_codes, dtype=self.dtype)
rvalue = value if is_list_like(value) else [value]
from pandas import Index
to_add = Index(rvalue).difference(self.categories)
# no assignments of values not in categories, but it's always ok to set
# something to np.nan
if len(to_add) and not isna(to_add).all():
raise ValueError(
"Cannot setitem on a Categorical with a new "
"category, set the categories first"
)
# set by position
if isinstance(key, (int, np.integer)):
pass
# tuple of indexers (dataframe)
elif isinstance(key, tuple):
# only allow 1 dimensional slicing, but can
# in a 2-d case be passd (slice(None),....)
if len(key) == 2:
if not com.is_null_slice(key[0]):
raise AssertionError("invalid slicing for a 1-ndim categorical")
key = key[1]
elif len(key) == 1:
key = key[0]
else:
raise AssertionError("invalid slicing for a 1-ndim categorical")
# slicing in Series or Categorical
elif isinstance(key, slice):
pass
# else: array of True/False in Series or Categorical
lindexer = self.categories.get_indexer(rvalue)
lindexer = self._maybe_coerce_indexer(lindexer)
key = check_array_indexer(self, key)
self._codes[key] = lindexer
def _reverse_indexer(self) -> Dict[Hashable, np.ndarray]:
"""
Compute the inverse of a categorical, returning
a dict of categories -> indexers.
*This is an internal function*
Returns
-------
dict of categories -> indexers
Examples
--------
>>> c = pd.Categorical(list('aabca'))
>>> c
[a, a, b, c, a]
Categories (3, object): [a, b, c]
>>> c.categories
Index(['a', 'b', 'c'], dtype='object')
>>> c.codes
array([0, 0, 1, 2, 0], dtype=int8)
>>> c._reverse_indexer()
{'a': array([0, 1, 4]), 'b': array([2]), 'c': array([3])}
"""
categories = self.categories
r, counts = libalgos.groupsort_indexer(
self.codes.astype("int64"), categories.size
)
counts = counts.cumsum()
_result = (r[start:end] for start, end in zip(counts, counts[1:]))
result = dict(zip(categories, _result))
return result
# reduction ops #
def _reduce(self, name, axis=0, **kwargs):
func = getattr(self, name, None)
if func is None:
raise TypeError(f"Categorical cannot perform the operation {name}")
return func(**kwargs)
@deprecate_kwarg(old_arg_name="numeric_only", new_arg_name="skipna")
def min(self, skipna=True):
"""
The minimum value of the object.
Only ordered `Categoricals` have a minimum!
.. versionchanged:: 1.0.0
Returns an NA value on empty arrays
Raises
------
TypeError
If the `Categorical` is not `ordered`.
Returns
-------
min : the minimum of this `Categorical`
"""
self.check_for_ordered("min")
if not len(self._codes):
return self.dtype.na_value
good = self._codes != -1
if not good.all():
if skipna:
pointer = self._codes[good].min()
else:
return np.nan
else:
pointer = self._codes.min()
return self.categories[pointer]
@deprecate_kwarg(old_arg_name="numeric_only", new_arg_name="skipna")
def max(self, skipna=True):
"""
The maximum value of the object.
Only ordered `Categoricals` have a maximum!
.. versionchanged:: 1.0.0
Returns an NA value on empty arrays
Raises
------
TypeError
If the `Categorical` is not `ordered`.
Returns
-------
max : the maximum of this `Categorical`
"""
self.check_for_ordered("max")
if not len(self._codes):
return self.dtype.na_value
good = self._codes != -1
if not good.all():
if skipna:
pointer = self._codes[good].max()
else:
return np.nan
else:
pointer = self._codes.max()
return self.categories[pointer]
def mode(self, dropna=True):
"""
Returns the mode(s) of the Categorical.
Always returns `Categorical` even if only one value.
Parameters
----------
dropna : bool, default True
Don't consider counts of NaN/NaT.
.. versionadded:: 0.24.0
Returns
-------
modes : `Categorical` (sorted)
"""
codes = self._codes
if dropna:
good = self._codes != -1
codes = self._codes[good]
codes = sorted(htable.mode_int64(ensure_int64(codes), dropna))
return self._constructor(values=codes, dtype=self.dtype, fastpath=True)
def unique(self):
"""
Return the ``Categorical`` which ``categories`` and ``codes`` are
unique. Unused categories are NOT returned.
- unordered category: values and categories are sorted by appearance
order.
- ordered category: values are sorted by appearance order, categories
keeps existing order.
Returns
-------
unique values : ``Categorical``
Examples
--------
An unordered Categorical will return categories in the
order of appearance.
>>> pd.Categorical(list('baabc'))
[b, a, c]
Categories (3, object): [b, a, c]
>>> pd.Categorical(list('baabc'), categories=list('abc'))
[b, a, c]
Categories (3, object): [b, a, c]
An ordered Categorical preserves the category ordering.
>>> pd.Categorical(list('baabc'),
... categories=list('abc'),
... ordered=True)
[b, a, c]
Categories (3, object): [a < b < c]
See Also
--------
unique
CategoricalIndex.unique
Series.unique
"""
# unlike np.unique, unique1d does not sort
unique_codes = unique1d(self.codes)
cat = self.copy()
# keep nan in codes
cat._codes = unique_codes
# exclude nan from indexer for categories
take_codes = unique_codes[unique_codes != -1]
if self.ordered:
take_codes = np.sort(take_codes)
return cat.set_categories(cat.categories.take(take_codes))
def _values_for_factorize(self):
codes = self.codes.astype("int64")
return codes, -1
@classmethod
def _from_factorized(cls, uniques, original):
return original._constructor(
original.categories.take(uniques), dtype=original.dtype
)
def equals(self, other):
"""
Returns True if categorical arrays are equal.
Parameters
----------
other : `Categorical`
Returns
-------
bool
"""
if self.is_dtype_equal(other):
if self.categories.equals(other.categories):
# fastpath to avoid re-coding
other_codes = other._codes
else:
other_codes = _recode_for_categories(
other.codes, other.categories, self.categories
)
return np.array_equal(self._codes, other_codes)
return False
def is_dtype_equal(self, other):
"""
Returns True if categoricals are the same dtype
same categories, and same ordered
Parameters
----------
other : Categorical
Returns
-------
bool
"""
try:
return hash(self.dtype) == hash(other.dtype)
except (AttributeError, TypeError):
return False
def describe(self):
"""
Describes this Categorical
Returns
-------
description: `DataFrame`
A dataframe with frequency and counts by category.
"""
counts = self.value_counts(dropna=False)
freqs = counts / float(counts.sum())
from pandas.core.reshape.concat import concat
result = concat([counts, freqs], axis=1)
result.columns = ["counts", "freqs"]
result.index.name = "categories"
return result
@Substitution(klass="Categorical")
@Appender(_extension_array_shared_docs["repeat"])
def repeat(self, repeats, axis=None):
nv.validate_repeat(tuple(), dict(axis=axis))
codes = self._codes.repeat(repeats)
return self._constructor(values=codes, dtype=self.dtype, fastpath=True)
# Implement the ExtensionArray interface
@property
def _can_hold_na(self):
return True
@classmethod
def _concat_same_type(self, to_concat):
from pandas.core.dtypes.concat import concat_categorical
return concat_categorical(to_concat)
def isin(self, values):
"""
Check whether `values` are contained in Categorical.
Return a boolean NumPy Array showing whether each element in
the Categorical matches an element in the passed sequence of
`values` exactly.
Parameters
----------
values : set or list-like
The sequence of values to test. Passing in a single string will
raise a ``TypeError``. Instead, turn a single string into a
list of one element.
Returns
-------
isin : numpy.ndarray (bool dtype)
Raises
------
TypeError
* If `values` is not a set or list-like
See Also
--------
pandas.Series.isin : Equivalent method on Series.
Examples
--------
>>> s = pd.Categorical(['lama', 'cow', 'lama', 'beetle', 'lama',
... 'hippo'])
>>> s.isin(['cow', 'lama'])
array([ True, True, True, False, True, False])
Passing a single string as ``s.isin('lama')`` will raise an error. Use
a list of one element instead:
>>> s.isin(['lama'])
array([ True, False, True, False, True, False])
"""
if not is_list_like(values):
values_type = type(values).__name__
raise TypeError(
"only list-like objects are allowed to be passed "
f"to isin(), you passed a [{values_type}]"
)
values = sanitize_array(values, None, None)
null_mask = np.asarray(isna(values))
code_values = self.categories.get_indexer(values)
code_values = code_values[null_mask | (code_values >= 0)]
return algorithms.isin(self.codes, code_values)
def replace(self, to_replace, value, inplace: bool = False):
"""
Replaces all instances of one value with another
Parameters
----------
to_replace: object
The value to be replaced
value: object
The value to replace it with
inplace: bool
Whether the operation is done in-place
Returns
-------
None if inplace is True, otherwise the new Categorical after replacement
Examples
--------
>>> s = pd.Categorical([1, 2, 1, 3])
>>> s.replace(1, 3)
[3, 3, 2, 3]
Categories (2, int64): [2, 3]
"""
inplace = validate_bool_kwarg(inplace, "inplace")
cat = self if inplace else self.copy()
if to_replace in cat.categories:
if isna(value):
cat.remove_categories(to_replace, inplace=True)
else:
categories = cat.categories.tolist()
index = categories.index(to_replace)
if value in cat.categories:
value_index = categories.index(value)
cat._codes[cat._codes == index] = value_index
cat.remove_categories(to_replace, inplace=True)
else:
categories[index] = value
cat.rename_categories(categories, inplace=True)
if not inplace:
return cat
# The Series.cat accessor
@delegate_names(
delegate=Categorical, accessors=["categories", "ordered"], typ="property"
)
@delegate_names(
delegate=Categorical,
accessors=[
"rename_categories",
"reorder_categories",
"add_categories",
"remove_categories",
"remove_unused_categories",
"set_categories",
"as_ordered",
"as_unordered",
],
typ="method",
)
class CategoricalAccessor(PandasDelegate, PandasObject, NoNewAttributesMixin):
"""
Accessor object for categorical properties of the Series values.
Be aware that assigning to `categories` is a inplace operation, while all
methods return new categorical data per default (but can be called with
`inplace=True`).
Parameters
----------
data : Series or CategoricalIndex
Examples
--------
>>> s.cat.categories
>>> s.cat.categories = list('abc')
>>> s.cat.rename_categories(list('cab'))
>>> s.cat.reorder_categories(list('cab'))
>>> s.cat.add_categories(['d','e'])
>>> s.cat.remove_categories(['d'])
>>> s.cat.remove_unused_categories()
>>> s.cat.set_categories(list('abcde'))
>>> s.cat.as_ordered()
>>> s.cat.as_unordered()
"""
def __init__(self, data):
self._validate(data)
self._parent = data.values
self._index = data.index
self._name = data.name
self._freeze()
@staticmethod
def _validate(data):
if not is_categorical_dtype(data.dtype):
raise AttributeError("Can only use .cat accessor with a 'category' dtype")
def _delegate_property_get(self, name):
return getattr(self._parent, name)
def _delegate_property_set(self, name, new_values):
return setattr(self._parent, name, new_values)
@property
def codes(self):
"""
Return Series of codes as well as the index.
"""
from pandas import Series
return Series(self._parent.codes, index=self._index)
def _delegate_method(self, name, *args, **kwargs):
from pandas import Series
method = getattr(self._parent, name)
res = method(*args, **kwargs)
if res is not None:
return Series(res, index=self._index, name=self._name)
# utility routines
def _get_codes_for_values(values, categories):
"""
utility routine to turn values into codes given the specified categories
"""
dtype_equal = is_dtype_equal(values.dtype, categories.dtype)
if dtype_equal:
# To prevent erroneous dtype coercion in _get_data_algo, retrieve
# the underlying numpy array. gh-22702
values = getattr(values, "_ndarray_values", values)
categories = getattr(categories, "_ndarray_values", categories)
elif is_extension_array_dtype(categories.dtype) and is_object_dtype(values):
# Support inferring the correct extension dtype from an array of
# scalar objects. e.g.
# Categorical(array[Period, Period], categories=PeriodIndex(...))
cls = categories.dtype.construct_array_type()
values = try_cast_to_ea(cls, values)
if not isinstance(values, cls):
# exception raised in _from_sequence
values = ensure_object(values)
categories = ensure_object(categories)
else:
values = ensure_object(values)
categories = ensure_object(categories)
hash_klass, vals = _get_data_algo(values)
_, cats = _get_data_algo(categories)
t = hash_klass(len(cats))
t.map_locations(cats)
return coerce_indexer_dtype(t.lookup(vals), cats)
def _recode_for_categories(codes: np.ndarray, old_categories, new_categories):
"""
Convert a set of codes for to a new set of categories
Parameters
----------
codes : np.ndarray
old_categories, new_categories : Index
Returns
-------
new_codes : np.ndarray[np.int64]
Examples
--------
>>> old_cat = pd.Index(['b', 'a', 'c'])
>>> new_cat = pd.Index(['a', 'b'])
>>> codes = np.array([0, 1, 1, 2])
>>> _recode_for_categories(codes, old_cat, new_cat)
array([ 1, 0, 0, -1])
"""
if len(old_categories) == 0:
# All null anyway, so just retain the nulls
return codes.copy()
elif new_categories.equals(old_categories):
# Same categories, so no need to actually recode
return codes.copy()
indexer = coerce_indexer_dtype(
new_categories.get_indexer(old_categories), new_categories
)
new_codes = take_1d(indexer, codes.copy(), fill_value=-1)
return new_codes
def _convert_to_list_like(list_like):
if hasattr(list_like, "dtype"):
return list_like
if isinstance(list_like, list):
return list_like
if is_sequence(list_like) or isinstance(list_like, tuple) or is_iterator(list_like):
return list(list_like)
elif is_scalar(list_like):
return [list_like]
else:
# TODO: is this reached?
return [list_like]
def factorize_from_iterable(values):
"""
Factorize an input `values` into `categories` and `codes`. Preserves
categorical dtype in `categories`.
*This is an internal function*
Parameters
----------
values : list-like
Returns
-------
codes : ndarray
categories : Index
If `values` has a categorical dtype, then `categories` is
a CategoricalIndex keeping the categories and order of `values`.
"""
if not is_list_like(values):
raise TypeError("Input must be list-like")
if is_categorical_dtype(values):
values = extract_array(values)
# The Categorical we want to build has the same categories
# as values but its codes are by def [0, ..., len(n_categories) - 1]
cat_codes = np.arange(len(values.categories), dtype=values.codes.dtype)
categories = Categorical.from_codes(cat_codes, dtype=values.dtype)
codes = values.codes
else:
# The value of ordered is irrelevant since we don't use cat as such,
# but only the resulting categories, the order of which is independent
# from ordered. Set ordered to False as default. See GH #15457
cat = Categorical(values, ordered=False)
categories = cat.categories
codes = cat.codes
return codes, categories
def factorize_from_iterables(iterables):
"""
A higher-level wrapper over `factorize_from_iterable`.
*This is an internal function*
Parameters
----------
iterables : list-like of list-likes
Returns
-------
codes_list : list of ndarrays
categories_list : list of Indexes
Notes
-----
See `factorize_from_iterable` for more info.
"""
if len(iterables) == 0:
# For consistency, it should return a list of 2 lists.
return [[], []]
return map(list, zip(*(factorize_from_iterable(it) for it in iterables)))
| BugsInPy/BugsInPy/temp/projects/pandas/bug-58-fixed/pandas/pandas/core/arrays/categorical.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-58-buggy/pandas/pandas/core/arrays/categorical.py |
pandas-bug-96 | from datetime import date, datetime, timedelta
import functools
import operator
from typing import Any, Optional
import warnings
from dateutil.easter import easter
import numpy as np
from pandas._libs.tslibs import (
NaT,
OutOfBoundsDatetime,
Period,
Timedelta,
Timestamp,
ccalendar,
conversion,
delta_to_nanoseconds,
frequencies as libfrequencies,
normalize_date,
offsets as liboffsets,
timezones,
)
from pandas._libs.tslibs.offsets import (
ApplyTypeError,
BaseOffset,
_get_calendar,
_is_normalized,
_to_dt64,
apply_index_wraps,
as_datetime,
roll_yearday,
shift_month,
)
from pandas.errors import AbstractMethodError
from pandas.util._decorators import Appender, Substitution, cache_readonly
from pandas.core.dtypes.inference import is_list_like
__all__ = [
"Day",
"BusinessDay",
"BDay",
"CustomBusinessDay",
"CDay",
"CBMonthEnd",
"CBMonthBegin",
"MonthBegin",
"BMonthBegin",
"MonthEnd",
"BMonthEnd",
"SemiMonthEnd",
"SemiMonthBegin",
"BusinessHour",
"CustomBusinessHour",
"YearBegin",
"BYearBegin",
"YearEnd",
"BYearEnd",
"QuarterBegin",
"BQuarterBegin",
"QuarterEnd",
"BQuarterEnd",
"LastWeekOfMonth",
"FY5253Quarter",
"FY5253",
"Week",
"WeekOfMonth",
"Easter",
"Hour",
"Minute",
"Second",
"Milli",
"Micro",
"Nano",
"DateOffset",
]
# convert to/from datetime/timestamp to allow invalid Timestamp ranges to
# pass thru
def as_timestamp(obj):
if isinstance(obj, Timestamp):
return obj
try:
return Timestamp(obj)
except (OutOfBoundsDatetime):
pass
return obj
def apply_wraps(func):
@functools.wraps(func)
def wrapper(self, other):
if other is NaT:
return NaT
elif isinstance(other, (timedelta, Tick, DateOffset)):
# timedelta path
return func(self, other)
elif isinstance(other, (np.datetime64, datetime, date)):
other = as_timestamp(other)
tz = getattr(other, "tzinfo", None)
nano = getattr(other, "nanosecond", 0)
try:
if self._adjust_dst and isinstance(other, Timestamp):
other = other.tz_localize(None)
result = func(self, other)
if self._adjust_dst:
result = conversion.localize_pydatetime(result, tz)
result = Timestamp(result)
if self.normalize:
result = result.normalize()
# nanosecond may be deleted depending on offset process
if not self.normalize and nano != 0:
if not isinstance(self, Nano) and result.nanosecond != nano:
if result.tz is not None:
# convert to UTC
value = conversion.tz_convert_single(
result.value, timezones.UTC, result.tz
)
else:
value = result.value
result = Timestamp(value + nano)
if tz is not None and result.tzinfo is None:
result = conversion.localize_pydatetime(result, tz)
except OutOfBoundsDatetime:
result = func(self, as_datetime(other))
if self.normalize:
# normalize_date returns normal datetime
result = normalize_date(result)
if tz is not None and result.tzinfo is None:
result = conversion.localize_pydatetime(result, tz)
result = Timestamp(result)
return result
return wrapper
# ---------------------------------------------------------------------
# DateOffset
class DateOffset(BaseOffset):
"""
Standard kind of date increment used for a date range.
Works exactly like relativedelta in terms of the keyword args you
pass in, use of the keyword n is discouraged-- you would be better
off specifying n in the keywords you use, but regardless it is
there for you. n is needed for DateOffset subclasses.
DateOffset work as follows. Each offset specify a set of dates
that conform to the DateOffset. For example, Bday defines this
set to be the set of dates that are weekdays (M-F). To test if a
date is in the set of a DateOffset dateOffset we can use the
is_on_offset method: dateOffset.is_on_offset(date).
If a date is not on a valid date, the rollback and rollforward
methods can be used to roll the date to the nearest valid date
before/after the date.
DateOffsets can be created to move dates forward a given number of
valid dates. For example, Bday(2) can be added to a date to move
it two business days forward. If the date does not start on a
valid date, first it is moved to a valid date. Thus pseudo code
is:
def __add__(date):
date = rollback(date) # does nothing if date is valid
return date + <n number of periods>
When a date offset is created for a negative number of periods,
the date is first rolled forward. The pseudo code is:
def __add__(date):
date = rollforward(date) # does nothing is date is valid
return date + <n number of periods>
Zero presents a problem. Should it roll forward or back? We
arbitrarily have it rollforward:
date + BDay(0) == BDay.rollforward(date)
Since 0 is a bit weird, we suggest avoiding its use.
Parameters
----------
n : int, default 1
The number of time periods the offset represents.
normalize : bool, default False
Whether to round the result of a DateOffset addition down to the
previous midnight.
**kwds
Temporal parameter that add to or replace the offset value.
Parameters that **add** to the offset (like Timedelta):
- years
- months
- weeks
- days
- hours
- minutes
- seconds
- microseconds
- nanoseconds
Parameters that **replace** the offset value:
- year
- month
- day
- weekday
- hour
- minute
- second
- microsecond
- nanosecond.
See Also
--------
dateutil.relativedelta.relativedelta : The relativedelta type is designed
to be applied to an existing datetime an can replace specific components of
that datetime, or represents an interval of time.
Examples
--------
>>> from pandas.tseries.offsets import DateOffset
>>> ts = pd.Timestamp('2017-01-01 09:10:11')
>>> ts + DateOffset(months=3)
Timestamp('2017-04-01 09:10:11')
>>> ts = pd.Timestamp('2017-01-01 09:10:11')
>>> ts + DateOffset(months=2)
Timestamp('2017-03-01 09:10:11')
"""
_params = cache_readonly(BaseOffset._params.fget)
_use_relativedelta = False
_adjust_dst = False
_attributes = frozenset(["n", "normalize"] + list(liboffsets.relativedelta_kwds))
_deprecations = frozenset(["isAnchored", "onOffset"])
# default for prior pickles
normalize = False
def __init__(self, n=1, normalize=False, **kwds):
BaseOffset.__init__(self, n, normalize)
off, use_rd = liboffsets._determine_offset(kwds)
object.__setattr__(self, "_offset", off)
object.__setattr__(self, "_use_relativedelta", use_rd)
for key in kwds:
val = kwds[key]
object.__setattr__(self, key, val)
@apply_wraps
def apply(self, other):
if self._use_relativedelta:
other = as_datetime(other)
if len(self.kwds) > 0:
tzinfo = getattr(other, "tzinfo", None)
if tzinfo is not None and self._use_relativedelta:
# perform calculation in UTC
other = other.replace(tzinfo=None)
if self.n > 0:
for i in range(self.n):
other = other + self._offset
else:
for i in range(-self.n):
other = other - self._offset
if tzinfo is not None and self._use_relativedelta:
# bring tz back from UTC calculation
other = conversion.localize_pydatetime(other, tzinfo)
return as_timestamp(other)
else:
return other + timedelta(self.n)
@apply_index_wraps
def apply_index(self, i):
"""
Vectorized apply of DateOffset to DatetimeIndex,
raises NotImplentedError for offsets without a
vectorized implementation.
Parameters
----------
i : DatetimeIndex
Returns
-------
y : DatetimeIndex
"""
if type(self) is not DateOffset:
raise NotImplementedError(
f"DateOffset subclass {type(self).__name__} "
"does not have a vectorized implementation"
)
kwds = self.kwds
relativedelta_fast = {
"years",
"months",
"weeks",
"days",
"hours",
"minutes",
"seconds",
"microseconds",
}
# relativedelta/_offset path only valid for base DateOffset
if self._use_relativedelta and set(kwds).issubset(relativedelta_fast):
months = (kwds.get("years", 0) * 12 + kwds.get("months", 0)) * self.n
if months:
shifted = liboffsets.shift_months(i.asi8, months)
i = type(i)(shifted, dtype=i.dtype)
weeks = (kwds.get("weeks", 0)) * self.n
if weeks:
# integer addition on PeriodIndex is deprecated,
# so we directly use _time_shift instead
asper = i.to_period("W")
if not isinstance(asper._data, np.ndarray):
# unwrap PeriodIndex --> PeriodArray
asper = asper._data
shifted = asper._time_shift(weeks)
i = shifted.to_timestamp() + i.to_perioddelta("W")
timedelta_kwds = {
k: v
for k, v in kwds.items()
if k in ["days", "hours", "minutes", "seconds", "microseconds"]
}
if timedelta_kwds:
delta = Timedelta(**timedelta_kwds)
i = i + (self.n * delta)
return i
elif not self._use_relativedelta and hasattr(self, "_offset"):
# timedelta
return i + (self._offset * self.n)
else:
# relativedelta with other keywords
kwd = set(kwds) - relativedelta_fast
raise NotImplementedError(
"DateOffset with relativedelta "
f"keyword(s) {kwd} not able to be "
"applied vectorized"
)
def is_anchored(self):
# TODO: Does this make sense for the general case? It would help
# if there were a canonical docstring for what is_anchored means.
return self.n == 1
def onOffset(self, dt):
warnings.warn(
"onOffset is a deprecated, use is_on_offset instead",
FutureWarning,
stacklevel=2,
)
return self.is_on_offset(dt)
def isAnchored(self):
warnings.warn(
"isAnchored is a deprecated, use is_anchored instead",
FutureWarning,
stacklevel=2,
)
return self.is_anchored()
# TODO: Combine this with BusinessMixin version by defining a whitelisted
# set of attributes on each object rather than the existing behavior of
# iterating over internal ``__dict__``
def _repr_attrs(self):
exclude = {"n", "inc", "normalize"}
attrs = []
for attr in sorted(self.__dict__):
if attr.startswith("_") or attr == "kwds":
continue
elif attr not in exclude:
value = getattr(self, attr)
attrs.append(f"{attr}={value}")
out = ""
if attrs:
out += ": " + ", ".join(attrs)
return out
@property
def name(self):
return self.rule_code
def rollback(self, dt):
"""
Roll provided date backward to next offset only if not on offset.
Returns
-------
TimeStamp
Rolled timestamp if not on offset, otherwise unchanged timestamp.
"""
dt = as_timestamp(dt)
if not self.is_on_offset(dt):
dt = dt - type(self)(1, normalize=self.normalize, **self.kwds)
return dt
def rollforward(self, dt):
"""
Roll provided date forward to next offset only if not on offset.
Returns
-------
TimeStamp
Rolled timestamp if not on offset, otherwise unchanged timestamp.
"""
dt = as_timestamp(dt)
if not self.is_on_offset(dt):
dt = dt + type(self)(1, normalize=self.normalize, **self.kwds)
return dt
def is_on_offset(self, dt):
if self.normalize and not _is_normalized(dt):
return False
# XXX, see #1395
if type(self) == DateOffset or isinstance(self, Tick):
return True
# Default (slow) method for determining if some date is a member of the
# date range generated by this offset. Subclasses may have this
# re-implemented in a nicer way.
a = dt
b = (dt + self) - self
return a == b
# way to get around weirdness with rule_code
@property
def _prefix(self):
raise NotImplementedError("Prefix not defined")
@property
def rule_code(self):
return self._prefix
@cache_readonly
def freqstr(self):
try:
code = self.rule_code
except NotImplementedError:
return repr(self)
if self.n != 1:
fstr = f"{self.n}{code}"
else:
fstr = code
try:
if self._offset:
fstr += self._offset_str()
except AttributeError:
# TODO: standardize `_offset` vs `offset` naming convention
pass
return fstr
def _offset_str(self):
return ""
@property
def nanos(self):
raise ValueError(f"{self} is a non-fixed frequency")
class SingleConstructorOffset(DateOffset):
@classmethod
def _from_name(cls, suffix=None):
# default _from_name calls cls with no args
if suffix:
raise ValueError(f"Bad freq suffix {suffix}")
return cls()
class _CustomMixin:
"""
Mixin for classes that define and validate calendar, holidays,
and weekdays attributes.
"""
def __init__(self, weekmask, holidays, calendar):
calendar, holidays = _get_calendar(
weekmask=weekmask, holidays=holidays, calendar=calendar
)
# Custom offset instances are identified by the
# following two attributes. See DateOffset._params()
# holidays, weekmask
object.__setattr__(self, "weekmask", weekmask)
object.__setattr__(self, "holidays", holidays)
object.__setattr__(self, "calendar", calendar)
class BusinessMixin:
"""
Mixin to business types to provide related functions.
"""
@property
def offset(self):
"""
Alias for self._offset.
"""
# Alias for backward compat
return self._offset
def _repr_attrs(self):
if self.offset:
attrs = [f"offset={repr(self.offset)}"]
else:
attrs = None
out = ""
if attrs:
out += ": " + ", ".join(attrs)
return out
class BusinessDay(BusinessMixin, SingleConstructorOffset):
"""
DateOffset subclass representing possibly n business days.
"""
_prefix = "B"
_adjust_dst = True
_attributes = frozenset(["n", "normalize", "offset"])
def __init__(self, n=1, normalize=False, offset=timedelta(0)):
BaseOffset.__init__(self, n, normalize)
object.__setattr__(self, "_offset", offset)
def _offset_str(self):
def get_str(td):
off_str = ""
if td.days > 0:
off_str += str(td.days) + "D"
if td.seconds > 0:
s = td.seconds
hrs = int(s / 3600)
if hrs != 0:
off_str += str(hrs) + "H"
s -= hrs * 3600
mts = int(s / 60)
if mts != 0:
off_str += str(mts) + "Min"
s -= mts * 60
if s != 0:
off_str += str(s) + "s"
if td.microseconds > 0:
off_str += str(td.microseconds) + "us"
return off_str
if isinstance(self.offset, timedelta):
zero = timedelta(0, 0, 0)
if self.offset >= zero:
off_str = "+" + get_str(self.offset)
else:
off_str = "-" + get_str(-self.offset)
return off_str
else:
return "+" + repr(self.offset)
@apply_wraps
def apply(self, other):
if isinstance(other, datetime):
n = self.n
wday = other.weekday()
# avoid slowness below by operating on weeks first
weeks = n // 5
if n <= 0 and wday > 4:
# roll forward
n += 1
n -= 5 * weeks
# n is always >= 0 at this point
if n == 0 and wday > 4:
# roll back
days = 4 - wday
elif wday > 4:
# roll forward
days = (7 - wday) + (n - 1)
elif wday + n <= 4:
# shift by n days without leaving the current week
days = n
else:
# shift by n days plus 2 to get past the weekend
days = n + 2
result = other + timedelta(days=7 * weeks + days)
if self.offset:
result = result + self.offset
return result
elif isinstance(other, (timedelta, Tick)):
return BDay(self.n, offset=self.offset + other, normalize=self.normalize)
else:
raise ApplyTypeError(
"Only know how to combine business day with datetime or timedelta."
)
@apply_index_wraps
def apply_index(self, i):
time = i.to_perioddelta("D")
# to_period rolls forward to next BDay; track and
# reduce n where it does when rolling forward
asper = i.to_period("B")
if not isinstance(asper._data, np.ndarray):
# unwrap PeriodIndex --> PeriodArray
asper = asper._data
if self.n > 0:
shifted = (i.to_perioddelta("B") - time).asi8 != 0
# Integer-array addition is deprecated, so we use
# _time_shift directly
roll = np.where(shifted, self.n - 1, self.n)
shifted = asper._addsub_int_array(roll, operator.add)
else:
# Integer addition is deprecated, so we use _time_shift directly
roll = self.n
shifted = asper._time_shift(roll)
result = shifted.to_timestamp() + time
return result
def is_on_offset(self, dt):
if self.normalize and not _is_normalized(dt):
return False
return dt.weekday() < 5
class BusinessHourMixin(BusinessMixin):
def __init__(self, start="09:00", end="17:00", offset=timedelta(0)):
# must be validated here to equality check
if not is_list_like(start):
start = [start]
if not len(start):
raise ValueError("Must include at least 1 start time")
if not is_list_like(end):
end = [end]
if not len(end):
raise ValueError("Must include at least 1 end time")
start = np.array([liboffsets._validate_business_time(x) for x in start])
end = np.array([liboffsets._validate_business_time(x) for x in end])
# Validation of input
if len(start) != len(end):
raise ValueError("number of starting time and ending time must be the same")
num_openings = len(start)
# sort starting and ending time by starting time
index = np.argsort(start)
# convert to tuple so that start and end are hashable
start = tuple(start[index])
end = tuple(end[index])
total_secs = 0
for i in range(num_openings):
total_secs += self._get_business_hours_by_sec(start[i], end[i])
total_secs += self._get_business_hours_by_sec(
end[i], start[(i + 1) % num_openings]
)
if total_secs != 24 * 60 * 60:
raise ValueError(
"invalid starting and ending time(s): "
"opening hours should not touch or overlap with "
"one another"
)
object.__setattr__(self, "start", start)
object.__setattr__(self, "end", end)
object.__setattr__(self, "_offset", offset)
@cache_readonly
def next_bday(self):
"""
Used for moving to next business day.
"""
if self.n >= 0:
nb_offset = 1
else:
nb_offset = -1
if self._prefix.startswith("C"):
# CustomBusinessHour
return CustomBusinessDay(
n=nb_offset,
weekmask=self.weekmask,
holidays=self.holidays,
calendar=self.calendar,
)
else:
return BusinessDay(n=nb_offset)
def _next_opening_time(self, other, sign=1):
"""
If self.n and sign have the same sign, return the earliest opening time
later than or equal to current time.
Otherwise the latest opening time earlier than or equal to current
time.
Opening time always locates on BusinessDay.
However, closing time may not if business hour extends over midnight.
Parameters
----------
other : datetime
Current time.
sign : int, default 1.
Either 1 or -1. Going forward in time if it has the same sign as
self.n. Going backward in time otherwise.
Returns
-------
result : datetime
Next opening time.
"""
earliest_start = self.start[0]
latest_start = self.start[-1]
if not self.next_bday.is_on_offset(other):
# today is not business day
other = other + sign * self.next_bday
if self.n * sign >= 0:
hour, minute = earliest_start.hour, earliest_start.minute
else:
hour, minute = latest_start.hour, latest_start.minute
else:
if self.n * sign >= 0:
if latest_start < other.time():
# current time is after latest starting time in today
other = other + sign * self.next_bday
hour, minute = earliest_start.hour, earliest_start.minute
else:
# find earliest starting time no earlier than current time
for st in self.start:
if other.time() <= st:
hour, minute = st.hour, st.minute
break
else:
if other.time() < earliest_start:
# current time is before earliest starting time in today
other = other + sign * self.next_bday
hour, minute = latest_start.hour, latest_start.minute
else:
# find latest starting time no later than current time
for st in reversed(self.start):
if other.time() >= st:
hour, minute = st.hour, st.minute
break
return datetime(other.year, other.month, other.day, hour, minute)
def _prev_opening_time(self, other):
"""
If n is positive, return the latest opening time earlier than or equal
to current time.
Otherwise the earliest opening time later than or equal to current
time.
Parameters
----------
other : datetime
Current time.
Returns
-------
result : datetime
Previous opening time.
"""
return self._next_opening_time(other, sign=-1)
def _get_business_hours_by_sec(self, start, end):
"""
Return business hours in a day by seconds.
"""
# create dummy datetime to calculate businesshours in a day
dtstart = datetime(2014, 4, 1, start.hour, start.minute)
day = 1 if start < end else 2
until = datetime(2014, 4, day, end.hour, end.minute)
return int((until - dtstart).total_seconds())
@apply_wraps
def rollback(self, dt):
"""
Roll provided date backward to next offset only if not on offset.
"""
if not self.is_on_offset(dt):
if self.n >= 0:
dt = self._prev_opening_time(dt)
else:
dt = self._next_opening_time(dt)
return self._get_closing_time(dt)
return dt
@apply_wraps
def rollforward(self, dt):
"""
Roll provided date forward to next offset only if not on offset.
"""
if not self.is_on_offset(dt):
if self.n >= 0:
return self._next_opening_time(dt)
else:
return self._prev_opening_time(dt)
return dt
def _get_closing_time(self, dt):
"""
Get the closing time of a business hour interval by its opening time.
Parameters
----------
dt : datetime
Opening time of a business hour interval.
Returns
-------
result : datetime
Corresponding closing time.
"""
for i, st in enumerate(self.start):
if st.hour == dt.hour and st.minute == dt.minute:
return dt + timedelta(
seconds=self._get_business_hours_by_sec(st, self.end[i])
)
assert False
@apply_wraps
def apply(self, other):
if isinstance(other, datetime):
# used for detecting edge condition
nanosecond = getattr(other, "nanosecond", 0)
# reset timezone and nanosecond
# other may be a Timestamp, thus not use replace
other = datetime(
other.year,
other.month,
other.day,
other.hour,
other.minute,
other.second,
other.microsecond,
)
n = self.n
# adjust other to reduce number of cases to handle
if n >= 0:
if other.time() in self.end or not self._is_on_offset(other):
other = self._next_opening_time(other)
else:
if other.time() in self.start:
# adjustment to move to previous business day
other = other - timedelta(seconds=1)
if not self._is_on_offset(other):
other = self._next_opening_time(other)
other = self._get_closing_time(other)
# get total business hours by sec in one business day
businesshours = sum(
self._get_business_hours_by_sec(st, en)
for st, en in zip(self.start, self.end)
)
bd, r = divmod(abs(n * 60), businesshours // 60)
if n < 0:
bd, r = -bd, -r
# adjust by business days first
if bd != 0:
skip_bd = BusinessDay(n=bd)
# midnight business hour may not on BusinessDay
if not self.next_bday.is_on_offset(other):
prev_open = self._prev_opening_time(other)
remain = other - prev_open
other = prev_open + skip_bd + remain
else:
other = other + skip_bd
# remaining business hours to adjust
bhour_remain = timedelta(minutes=r)
if n >= 0:
while bhour_remain != timedelta(0):
# business hour left in this business time interval
bhour = (
self._get_closing_time(self._prev_opening_time(other)) - other
)
if bhour_remain < bhour:
# finish adjusting if possible
other += bhour_remain
bhour_remain = timedelta(0)
else:
# go to next business time interval
bhour_remain -= bhour
other = self._next_opening_time(other + bhour)
else:
while bhour_remain != timedelta(0):
# business hour left in this business time interval
bhour = self._next_opening_time(other) - other
if (
bhour_remain > bhour
or bhour_remain == bhour
and nanosecond != 0
):
# finish adjusting if possible
other += bhour_remain
bhour_remain = timedelta(0)
else:
# go to next business time interval
bhour_remain -= bhour
other = self._get_closing_time(
self._next_opening_time(
other + bhour - timedelta(seconds=1)
)
)
return other
else:
raise ApplyTypeError("Only know how to combine business hour with datetime")
def is_on_offset(self, dt):
if self.normalize and not _is_normalized(dt):
return False
if dt.tzinfo is not None:
dt = datetime(
dt.year, dt.month, dt.day, dt.hour, dt.minute, dt.second, dt.microsecond
)
# Valid BH can be on the different BusinessDay during midnight
# Distinguish by the time spent from previous opening time
return self._is_on_offset(dt)
def _is_on_offset(self, dt):
"""
Slight speedups using calculated values.
"""
# if self.normalize and not _is_normalized(dt):
# return False
# Valid BH can be on the different BusinessDay during midnight
# Distinguish by the time spent from previous opening time
if self.n >= 0:
op = self._prev_opening_time(dt)
else:
op = self._next_opening_time(dt)
span = (dt - op).total_seconds()
businesshours = 0
for i, st in enumerate(self.start):
if op.hour == st.hour and op.minute == st.minute:
businesshours = self._get_business_hours_by_sec(st, self.end[i])
if span <= businesshours:
return True
else:
return False
def _repr_attrs(self):
out = super()._repr_attrs()
hours = ",".join(
f'{st.strftime("%H:%M")}-{en.strftime("%H:%M")}'
for st, en in zip(self.start, self.end)
)
attrs = [f"{self._prefix}={hours}"]
out += ": " + ", ".join(attrs)
return out
class BusinessHour(BusinessHourMixin, SingleConstructorOffset):
"""
DateOffset subclass representing possibly n business hours.
"""
_prefix = "BH"
_anchor = 0
_attributes = frozenset(["n", "normalize", "start", "end", "offset"])
def __init__(
self, n=1, normalize=False, start="09:00", end="17:00", offset=timedelta(0)
):
BaseOffset.__init__(self, n, normalize)
super().__init__(start=start, end=end, offset=offset)
class CustomBusinessDay(_CustomMixin, BusinessDay):
"""
DateOffset subclass representing possibly n custom business days,
excluding holidays.
Parameters
----------
n : int, default 1
normalize : bool, default False
Normalize start/end dates to midnight before generating date range.
weekmask : str, Default 'Mon Tue Wed Thu Fri'
Weekmask of valid business days, passed to ``numpy.busdaycalendar``.
holidays : list
List/array of dates to exclude from the set of valid business days,
passed to ``numpy.busdaycalendar``.
calendar : pd.HolidayCalendar or np.busdaycalendar
offset : timedelta, default timedelta(0)
"""
_prefix = "C"
_attributes = frozenset(
["n", "normalize", "weekmask", "holidays", "calendar", "offset"]
)
def __init__(
self,
n=1,
normalize=False,
weekmask="Mon Tue Wed Thu Fri",
holidays=None,
calendar=None,
offset=timedelta(0),
):
BaseOffset.__init__(self, n, normalize)
object.__setattr__(self, "_offset", offset)
_CustomMixin.__init__(self, weekmask, holidays, calendar)
@apply_wraps
def apply(self, other):
if self.n <= 0:
roll = "forward"
else:
roll = "backward"
if isinstance(other, datetime):
date_in = other
np_dt = np.datetime64(date_in.date())
np_incr_dt = np.busday_offset(
np_dt, self.n, roll=roll, busdaycal=self.calendar
)
dt_date = np_incr_dt.astype(datetime)
result = datetime.combine(dt_date, date_in.time())
if self.offset:
result = result + self.offset
return result
elif isinstance(other, (timedelta, Tick)):
return BDay(self.n, offset=self.offset + other, normalize=self.normalize)
else:
raise ApplyTypeError(
"Only know how to combine trading day with "
"datetime, datetime64 or timedelta."
)
def apply_index(self, i):
raise NotImplementedError
def is_on_offset(self, dt):
if self.normalize and not _is_normalized(dt):
return False
day64 = _to_dt64(dt, "datetime64[D]")
return np.is_busday(day64, busdaycal=self.calendar)
class CustomBusinessHour(_CustomMixin, BusinessHourMixin, SingleConstructorOffset):
"""
DateOffset subclass representing possibly n custom business days.
"""
_prefix = "CBH"
_anchor = 0
_attributes = frozenset(
["n", "normalize", "weekmask", "holidays", "calendar", "start", "end", "offset"]
)
def __init__(
self,
n=1,
normalize=False,
weekmask="Mon Tue Wed Thu Fri",
holidays=None,
calendar=None,
start="09:00",
end="17:00",
offset=timedelta(0),
):
BaseOffset.__init__(self, n, normalize)
object.__setattr__(self, "_offset", offset)
_CustomMixin.__init__(self, weekmask, holidays, calendar)
BusinessHourMixin.__init__(self, start=start, end=end, offset=offset)
# ---------------------------------------------------------------------
# Month-Based Offset Classes
class MonthOffset(SingleConstructorOffset):
_adjust_dst = True
_attributes = frozenset(["n", "normalize"])
__init__ = BaseOffset.__init__
@property
def name(self):
if self.is_anchored:
return self.rule_code
else:
month = ccalendar.MONTH_ALIASES[self.n]
return f"{self.code_rule}-{month}"
def is_on_offset(self, dt):
if self.normalize and not _is_normalized(dt):
return False
return dt.day == self._get_offset_day(dt)
@apply_wraps
def apply(self, other):
compare_day = self._get_offset_day(other)
n = liboffsets.roll_convention(other.day, self.n, compare_day)
return shift_month(other, n, self._day_opt)
@apply_index_wraps
def apply_index(self, i):
shifted = liboffsets.shift_months(i.asi8, self.n, self._day_opt)
# TODO: going through __new__ raises on call to _validate_frequency;
# are we passing incorrect freq?
return type(i)._simple_new(shifted, freq=i.freq, dtype=i.dtype)
class MonthEnd(MonthOffset):
"""
DateOffset of one month end.
"""
_prefix = "M"
_day_opt = "end"
class MonthBegin(MonthOffset):
"""
DateOffset of one month at beginning.
"""
_prefix = "MS"
_day_opt = "start"
class BusinessMonthEnd(MonthOffset):
"""
DateOffset increments between business EOM dates.
"""
_prefix = "BM"
_day_opt = "business_end"
class BusinessMonthBegin(MonthOffset):
"""
DateOffset of one business month at beginning.
"""
_prefix = "BMS"
_day_opt = "business_start"
class _CustomBusinessMonth(_CustomMixin, BusinessMixin, MonthOffset):
"""
DateOffset subclass representing custom business month(s).
Increments between %(bound)s of month dates.
Parameters
----------
n : int, default 1
The number of months represented.
normalize : bool, default False
Normalize start/end dates to midnight before generating date range.
weekmask : str, Default 'Mon Tue Wed Thu Fri'
Weekmask of valid business days, passed to ``numpy.busdaycalendar``.
holidays : list
List/array of dates to exclude from the set of valid business days,
passed to ``numpy.busdaycalendar``.
calendar : pd.HolidayCalendar or np.busdaycalendar
Calendar to integrate.
offset : timedelta, default timedelta(0)
Time offset to apply.
"""
_attributes = frozenset(
["n", "normalize", "weekmask", "holidays", "calendar", "offset"]
)
is_on_offset = DateOffset.is_on_offset # override MonthOffset method
apply_index = DateOffset.apply_index # override MonthOffset method
def __init__(
self,
n=1,
normalize=False,
weekmask="Mon Tue Wed Thu Fri",
holidays=None,
calendar=None,
offset=timedelta(0),
):
BaseOffset.__init__(self, n, normalize)
object.__setattr__(self, "_offset", offset)
_CustomMixin.__init__(self, weekmask, holidays, calendar)
@cache_readonly
def cbday_roll(self):
"""
Define default roll function to be called in apply method.
"""
cbday = CustomBusinessDay(n=self.n, normalize=False, **self.kwds)
if self._prefix.endswith("S"):
# MonthBegin
roll_func = cbday.rollforward
else:
# MonthEnd
roll_func = cbday.rollback
return roll_func
@cache_readonly
def m_offset(self):
if self._prefix.endswith("S"):
# MonthBegin
moff = MonthBegin(n=1, normalize=False)
else:
# MonthEnd
moff = MonthEnd(n=1, normalize=False)
return moff
@cache_readonly
def month_roll(self):
"""
Define default roll function to be called in apply method.
"""
if self._prefix.endswith("S"):
# MonthBegin
roll_func = self.m_offset.rollback
else:
# MonthEnd
roll_func = self.m_offset.rollforward
return roll_func
@apply_wraps
def apply(self, other):
# First move to month offset
cur_month_offset_date = self.month_roll(other)
# Find this custom month offset
compare_date = self.cbday_roll(cur_month_offset_date)
n = liboffsets.roll_convention(other.day, self.n, compare_date.day)
new = cur_month_offset_date + n * self.m_offset
result = self.cbday_roll(new)
return result
@Substitution(bound="end")
@Appender(_CustomBusinessMonth.__doc__)
class CustomBusinessMonthEnd(_CustomBusinessMonth):
_prefix = "CBM"
@Substitution(bound="beginning")
@Appender(_CustomBusinessMonth.__doc__)
class CustomBusinessMonthBegin(_CustomBusinessMonth):
_prefix = "CBMS"
# ---------------------------------------------------------------------
# Semi-Month Based Offset Classes
class SemiMonthOffset(DateOffset):
_adjust_dst = True
_default_day_of_month = 15
_min_day_of_month = 2
_attributes = frozenset(["n", "normalize", "day_of_month"])
def __init__(self, n=1, normalize=False, day_of_month=None):
BaseOffset.__init__(self, n, normalize)
if day_of_month is None:
object.__setattr__(self, "day_of_month", self._default_day_of_month)
else:
object.__setattr__(self, "day_of_month", int(day_of_month))
if not self._min_day_of_month <= self.day_of_month <= 27:
raise ValueError(
"day_of_month must be "
f"{self._min_day_of_month}<=day_of_month<=27, "
f"got {self.day_of_month}"
)
@classmethod
def _from_name(cls, suffix=None):
return cls(day_of_month=suffix)
@property
def rule_code(self):
suffix = f"-{self.day_of_month}"
return self._prefix + suffix
@apply_wraps
def apply(self, other):
# shift `other` to self.day_of_month, incrementing `n` if necessary
n = liboffsets.roll_convention(other.day, self.n, self.day_of_month)
days_in_month = ccalendar.get_days_in_month(other.year, other.month)
# For SemiMonthBegin on other.day == 1 and
# SemiMonthEnd on other.day == days_in_month,
# shifting `other` to `self.day_of_month` _always_ requires
# incrementing/decrementing `n`, regardless of whether it is
# initially positive.
if type(self) is SemiMonthBegin and (self.n <= 0 and other.day == 1):
n -= 1
elif type(self) is SemiMonthEnd and (self.n > 0 and other.day == days_in_month):
n += 1
return self._apply(n, other)
def _apply(self, n, other):
"""
Handle specific apply logic for child classes.
"""
raise AbstractMethodError(self)
@apply_index_wraps
def apply_index(self, i):
# determine how many days away from the 1st of the month we are
dti = i
days_from_start = i.to_perioddelta("M").asi8
delta = Timedelta(days=self.day_of_month - 1).value
# get boolean array for each element before the day_of_month
before_day_of_month = days_from_start < delta
# get boolean array for each element after the day_of_month
after_day_of_month = days_from_start > delta
# determine the correct n for each date in i
roll = self._get_roll(i, before_day_of_month, after_day_of_month)
# isolate the time since it will be striped away one the next line
time = i.to_perioddelta("D")
# apply the correct number of months
# integer-array addition on PeriodIndex is deprecated,
# so we use _addsub_int_array directly
asper = i.to_period("M")
if not isinstance(asper._data, np.ndarray):
# unwrap PeriodIndex --> PeriodArray
asper = asper._data
shifted = asper._addsub_int_array(roll // 2, operator.add)
i = type(dti)(shifted.to_timestamp())
# apply the correct day
i = self._apply_index_days(i, roll)
return i + time
def _get_roll(self, i, before_day_of_month, after_day_of_month):
"""
Return an array with the correct n for each date in i.
The roll array is based on the fact that i gets rolled back to
the first day of the month.
"""
raise AbstractMethodError(self)
def _apply_index_days(self, i, roll):
"""
Apply the correct day for each date in i.
"""
raise AbstractMethodError(self)
class SemiMonthEnd(SemiMonthOffset):
"""
Two DateOffset's per month repeating on the last
day of the month and day_of_month.
Parameters
----------
n : int
normalize : bool, default False
day_of_month : int, {1, 3,...,27}, default 15
"""
_prefix = "SM"
_min_day_of_month = 1
def is_on_offset(self, dt):
if self.normalize and not _is_normalized(dt):
return False
days_in_month = ccalendar.get_days_in_month(dt.year, dt.month)
return dt.day in (self.day_of_month, days_in_month)
def _apply(self, n, other):
months = n // 2
day = 31 if n % 2 else self.day_of_month
return shift_month(other, months, day)
def _get_roll(self, i, before_day_of_month, after_day_of_month):
n = self.n
is_month_end = i.is_month_end
if n > 0:
roll_end = np.where(is_month_end, 1, 0)
roll_before = np.where(before_day_of_month, n, n + 1)
roll = roll_end + roll_before
elif n == 0:
roll_after = np.where(after_day_of_month, 2, 0)
roll_before = np.where(~after_day_of_month, 1, 0)
roll = roll_before + roll_after
else:
roll = np.where(after_day_of_month, n + 2, n + 1)
return roll
def _apply_index_days(self, i, roll):
"""
Add days portion of offset to DatetimeIndex i.
Parameters
----------
i : DatetimeIndex
roll : ndarray[int64_t]
Returns
-------
result : DatetimeIndex
"""
nanos = (roll % 2) * Timedelta(days=self.day_of_month).value
i += nanos.astype("timedelta64[ns]")
return i + Timedelta(days=-1)
class SemiMonthBegin(SemiMonthOffset):
"""
Two DateOffset's per month repeating on the first
day of the month and day_of_month.
Parameters
----------
n : int
normalize : bool, default False
day_of_month : int, {2, 3,...,27}, default 15
"""
_prefix = "SMS"
def is_on_offset(self, dt):
if self.normalize and not _is_normalized(dt):
return False
return dt.day in (1, self.day_of_month)
def _apply(self, n, other):
months = n // 2 + n % 2
day = 1 if n % 2 else self.day_of_month
return shift_month(other, months, day)
def _get_roll(self, i, before_day_of_month, after_day_of_month):
n = self.n
is_month_start = i.is_month_start
if n > 0:
roll = np.where(before_day_of_month, n, n + 1)
elif n == 0:
roll_start = np.where(is_month_start, 0, 1)
roll_after = np.where(after_day_of_month, 1, 0)
roll = roll_start + roll_after
else:
roll_after = np.where(after_day_of_month, n + 2, n + 1)
roll_start = np.where(is_month_start, -1, 0)
roll = roll_after + roll_start
return roll
def _apply_index_days(self, i, roll):
"""
Add days portion of offset to DatetimeIndex i.
Parameters
----------
i : DatetimeIndex
roll : ndarray[int64_t]
Returns
-------
result : DatetimeIndex
"""
nanos = (roll % 2) * Timedelta(days=self.day_of_month - 1).value
return i + nanos.astype("timedelta64[ns]")
# ---------------------------------------------------------------------
# Week-Based Offset Classes
class Week(DateOffset):
"""
Weekly offset.
Parameters
----------
weekday : int, default None
Always generate specific day of week. 0 for Monday.
"""
_adjust_dst = True
_inc = timedelta(weeks=1)
_prefix = "W"
_attributes = frozenset(["n", "normalize", "weekday"])
def __init__(self, n=1, normalize=False, weekday=None):
BaseOffset.__init__(self, n, normalize)
object.__setattr__(self, "weekday", weekday)
if self.weekday is not None:
if self.weekday < 0 or self.weekday > 6:
raise ValueError(f"Day must be 0<=day<=6, got {self.weekday}")
def is_anchored(self):
return self.n == 1 and self.weekday is not None
@apply_wraps
def apply(self, other):
if self.weekday is None:
return other + self.n * self._inc
if not isinstance(other, datetime):
raise TypeError(
f"Cannot add {type(other).__name__} to {type(self).__name__}"
)
k = self.n
otherDay = other.weekday()
if otherDay != self.weekday:
other = other + timedelta((self.weekday - otherDay) % 7)
if k > 0:
k -= 1
return other + timedelta(weeks=k)
@apply_index_wraps
def apply_index(self, i):
if self.weekday is None:
# integer addition on PeriodIndex is deprecated,
# so we use _time_shift directly
asper = i.to_period("W")
if not isinstance(asper._data, np.ndarray):
# unwrap PeriodIndex --> PeriodArray
asper = asper._data
shifted = asper._time_shift(self.n)
return shifted.to_timestamp() + i.to_perioddelta("W")
else:
return self._end_apply_index(i)
def _end_apply_index(self, dtindex):
"""
Add self to the given DatetimeIndex, specialized for case where
self.weekday is non-null.
Parameters
----------
dtindex : DatetimeIndex
Returns
-------
result : DatetimeIndex
"""
off = dtindex.to_perioddelta("D")
base, mult = libfrequencies.get_freq_code(self.freqstr)
base_period = dtindex.to_period(base)
if not isinstance(base_period._data, np.ndarray):
# unwrap PeriodIndex --> PeriodArray
base_period = base_period._data
if self.n > 0:
# when adding, dates on end roll to next
normed = dtindex - off + Timedelta(1, "D") - Timedelta(1, "ns")
roll = np.where(
base_period.to_timestamp(how="end") == normed, self.n, self.n - 1
)
# integer-array addition on PeriodIndex is deprecated,
# so we use _addsub_int_array directly
shifted = base_period._addsub_int_array(roll, operator.add)
base = shifted.to_timestamp(how="end")
else:
# integer addition on PeriodIndex is deprecated,
# so we use _time_shift directly
roll = self.n
base = base_period._time_shift(roll).to_timestamp(how="end")
return base + off + Timedelta(1, "ns") - Timedelta(1, "D")
def is_on_offset(self, dt):
if self.normalize and not _is_normalized(dt):
return False
elif self.weekday is None:
return True
return dt.weekday() == self.weekday
@property
def rule_code(self):
suffix = ""
if self.weekday is not None:
weekday = ccalendar.int_to_weekday[self.weekday]
suffix = f"-{weekday}"
return self._prefix + suffix
@classmethod
def _from_name(cls, suffix=None):
if not suffix:
weekday = None
else:
weekday = ccalendar.weekday_to_int[suffix]
return cls(weekday=weekday)
class _WeekOfMonthMixin:
"""
Mixin for methods common to WeekOfMonth and LastWeekOfMonth.
"""
@apply_wraps
def apply(self, other):
compare_day = self._get_offset_day(other)
months = self.n
if months > 0 and compare_day > other.day:
months -= 1
elif months <= 0 and compare_day < other.day:
months += 1
shifted = shift_month(other, months, "start")
to_day = self._get_offset_day(shifted)
return liboffsets.shift_day(shifted, to_day - shifted.day)
def is_on_offset(self, dt):
if self.normalize and not _is_normalized(dt):
return False
return dt.day == self._get_offset_day(dt)
class WeekOfMonth(_WeekOfMonthMixin, DateOffset):
"""
Describes monthly dates like "the Tuesday of the 2nd week of each month".
Parameters
----------
n : int
week : int {0, 1, 2, 3, ...}, default 0
A specific integer for the week of the month.
e.g. 0 is 1st week of month, 1 is the 2nd week, etc.
weekday : int {0, 1, ..., 6}, default 0
A specific integer for the day of the week.
- 0 is Monday
- 1 is Tuesday
- 2 is Wednesday
- 3 is Thursday
- 4 is Friday
- 5 is Saturday
- 6 is Sunday.
"""
_prefix = "WOM"
_adjust_dst = True
_attributes = frozenset(["n", "normalize", "week", "weekday"])
def __init__(self, n=1, normalize=False, week=0, weekday=0):
BaseOffset.__init__(self, n, normalize)
object.__setattr__(self, "weekday", weekday)
object.__setattr__(self, "week", week)
if self.weekday < 0 or self.weekday > 6:
raise ValueError(f"Day must be 0<=day<=6, got {self.weekday}")
if self.week < 0 or self.week > 3:
raise ValueError(f"Week must be 0<=week<=3, got {self.week}")
def _get_offset_day(self, other):
"""
Find the day in the same month as other that has the same
weekday as self.weekday and is the self.week'th such day in the month.
Parameters
----------
other : datetime
Returns
-------
day : int
"""
mstart = datetime(other.year, other.month, 1)
wday = mstart.weekday()
shift_days = (self.weekday - wday) % 7
return 1 + shift_days + self.week * 7
@property
def rule_code(self):
weekday = ccalendar.int_to_weekday.get(self.weekday, "")
return f"{self._prefix}-{self.week + 1}{weekday}"
@classmethod
def _from_name(cls, suffix=None):
if not suffix:
raise ValueError(f"Prefix {repr(cls._prefix)} requires a suffix.")
# TODO: handle n here...
# only one digit weeks (1 --> week 0, 2 --> week 1, etc.)
week = int(suffix[0]) - 1
weekday = ccalendar.weekday_to_int[suffix[1:]]
return cls(week=week, weekday=weekday)
class LastWeekOfMonth(_WeekOfMonthMixin, DateOffset):
"""
Describes monthly dates in last week of month like "the last Tuesday of
each month".
Parameters
----------
n : int, default 1
weekday : int {0, 1, ..., 6}, default 0
A specific integer for the day of the week.
- 0 is Monday
- 1 is Tuesday
- 2 is Wednesday
- 3 is Thursday
- 4 is Friday
- 5 is Saturday
- 6 is Sunday.
"""
_prefix = "LWOM"
_adjust_dst = True
_attributes = frozenset(["n", "normalize", "weekday"])
def __init__(self, n=1, normalize=False, weekday=0):
BaseOffset.__init__(self, n, normalize)
object.__setattr__(self, "weekday", weekday)
if self.n == 0:
raise ValueError("N cannot be 0")
if self.weekday < 0 or self.weekday > 6:
raise ValueError(f"Day must be 0<=day<=6, got {self.weekday}")
def _get_offset_day(self, other):
"""
Find the day in the same month as other that has the same
weekday as self.weekday and is the last such day in the month.
Parameters
----------
other: datetime
Returns
-------
day: int
"""
dim = ccalendar.get_days_in_month(other.year, other.month)
mend = datetime(other.year, other.month, dim)
wday = mend.weekday()
shift_days = (wday - self.weekday) % 7
return dim - shift_days
@property
def rule_code(self):
weekday = ccalendar.int_to_weekday.get(self.weekday, "")
return f"{self._prefix}-{weekday}"
@classmethod
def _from_name(cls, suffix=None):
if not suffix:
raise ValueError(f"Prefix {repr(cls._prefix)} requires a suffix.")
# TODO: handle n here...
weekday = ccalendar.weekday_to_int[suffix]
return cls(weekday=weekday)
# ---------------------------------------------------------------------
# Quarter-Based Offset Classes
class QuarterOffset(DateOffset):
"""
Quarter representation - doesn't call super.
"""
_default_startingMonth: Optional[int] = None
_from_name_startingMonth: Optional[int] = None
_adjust_dst = True
_attributes = frozenset(["n", "normalize", "startingMonth"])
# TODO: Consider combining QuarterOffset and YearOffset __init__ at some
# point. Also apply_index, is_on_offset, rule_code if
# startingMonth vs month attr names are resolved
def __init__(self, n=1, normalize=False, startingMonth=None):
BaseOffset.__init__(self, n, normalize)
if startingMonth is None:
startingMonth = self._default_startingMonth
object.__setattr__(self, "startingMonth", startingMonth)
def is_anchored(self):
return self.n == 1 and self.startingMonth is not None
@classmethod
def _from_name(cls, suffix=None):
kwargs = {}
if suffix:
kwargs["startingMonth"] = ccalendar.MONTH_TO_CAL_NUM[suffix]
else:
if cls._from_name_startingMonth is not None:
kwargs["startingMonth"] = cls._from_name_startingMonth
return cls(**kwargs)
@property
def rule_code(self):
month = ccalendar.MONTH_ALIASES[self.startingMonth]
return f"{self._prefix}-{month}"
@apply_wraps
def apply(self, other):
# months_since: find the calendar quarter containing other.month,
# e.g. if other.month == 8, the calendar quarter is [Jul, Aug, Sep].
# Then find the month in that quarter containing an is_on_offset date for
# self. `months_since` is the number of months to shift other.month
# to get to this on-offset month.
months_since = other.month % 3 - self.startingMonth % 3
qtrs = liboffsets.roll_qtrday(
other, self.n, self.startingMonth, day_opt=self._day_opt, modby=3
)
months = qtrs * 3 - months_since
return shift_month(other, months, self._day_opt)
def is_on_offset(self, dt):
if self.normalize and not _is_normalized(dt):
return False
mod_month = (dt.month - self.startingMonth) % 3
return mod_month == 0 and dt.day == self._get_offset_day(dt)
@apply_index_wraps
def apply_index(self, dtindex):
shifted = liboffsets.shift_quarters(
dtindex.asi8, self.n, self.startingMonth, self._day_opt
)
# TODO: going through __new__ raises on call to _validate_frequency;
# are we passing incorrect freq?
return type(dtindex)._simple_new(
shifted, freq=dtindex.freq, dtype=dtindex.dtype
)
class BQuarterEnd(QuarterOffset):
"""
DateOffset increments between business Quarter dates.
startingMonth = 1 corresponds to dates like 1/31/2007, 4/30/2007, ...
startingMonth = 2 corresponds to dates like 2/28/2007, 5/31/2007, ...
startingMonth = 3 corresponds to dates like 3/30/2007, 6/29/2007, ...
"""
_outputName = "BusinessQuarterEnd"
_default_startingMonth = 3
_from_name_startingMonth = 12
_prefix = "BQ"
_day_opt = "business_end"
# TODO: This is basically the same as BQuarterEnd
class BQuarterBegin(QuarterOffset):
_outputName = "BusinessQuarterBegin"
# I suspect this is wrong for *all* of them.
_default_startingMonth = 3
_from_name_startingMonth = 1
_prefix = "BQS"
_day_opt = "business_start"
class QuarterEnd(QuarterOffset):
"""
DateOffset increments between business Quarter dates.
startingMonth = 1 corresponds to dates like 1/31/2007, 4/30/2007, ...
startingMonth = 2 corresponds to dates like 2/28/2007, 5/31/2007, ...
startingMonth = 3 corresponds to dates like 3/31/2007, 6/30/2007, ...
"""
_outputName = "QuarterEnd"
_default_startingMonth = 3
_prefix = "Q"
_day_opt = "end"
class QuarterBegin(QuarterOffset):
_outputName = "QuarterBegin"
_default_startingMonth = 3
_from_name_startingMonth = 1
_prefix = "QS"
_day_opt = "start"
# ---------------------------------------------------------------------
# Year-Based Offset Classes
class YearOffset(DateOffset):
"""
DateOffset that just needs a month.
"""
_adjust_dst = True
_attributes = frozenset(["n", "normalize", "month"])
def _get_offset_day(self, other):
# override BaseOffset method to use self.month instead of other.month
# TODO: there may be a more performant way to do this
return liboffsets.get_day_of_month(
other.replace(month=self.month), self._day_opt
)
@apply_wraps
def apply(self, other):
years = roll_yearday(other, self.n, self.month, self._day_opt)
months = years * 12 + (self.month - other.month)
return shift_month(other, months, self._day_opt)
@apply_index_wraps
def apply_index(self, dtindex):
shifted = liboffsets.shift_quarters(
dtindex.asi8, self.n, self.month, self._day_opt, modby=12
)
# TODO: going through __new__ raises on call to _validate_frequency;
# are we passing incorrect freq?
return type(dtindex)._simple_new(
shifted, freq=dtindex.freq, dtype=dtindex.dtype
)
def is_on_offset(self, dt):
if self.normalize and not _is_normalized(dt):
return False
return dt.month == self.month and dt.day == self._get_offset_day(dt)
def __init__(self, n=1, normalize=False, month=None):
BaseOffset.__init__(self, n, normalize)
month = month if month is not None else self._default_month
object.__setattr__(self, "month", month)
if self.month < 1 or self.month > 12:
raise ValueError("Month must go from 1 to 12")
@classmethod
def _from_name(cls, suffix=None):
kwargs = {}
if suffix:
kwargs["month"] = ccalendar.MONTH_TO_CAL_NUM[suffix]
return cls(**kwargs)
@property
def rule_code(self):
month = ccalendar.MONTH_ALIASES[self.month]
return f"{self._prefix}-{month}"
class BYearEnd(YearOffset):
"""
DateOffset increments between business EOM dates.
"""
_outputName = "BusinessYearEnd"
_default_month = 12
_prefix = "BA"
_day_opt = "business_end"
class BYearBegin(YearOffset):
"""
DateOffset increments between business year begin dates.
"""
_outputName = "BusinessYearBegin"
_default_month = 1
_prefix = "BAS"
_day_opt = "business_start"
class YearEnd(YearOffset):
"""
DateOffset increments between calendar year ends.
"""
_default_month = 12
_prefix = "A"
_day_opt = "end"
class YearBegin(YearOffset):
"""
DateOffset increments between calendar year begin dates.
"""
_default_month = 1
_prefix = "AS"
_day_opt = "start"
# ---------------------------------------------------------------------
# Special Offset Classes
class FY5253(DateOffset):
"""
Describes 52-53 week fiscal year. This is also known as a 4-4-5 calendar.
It is used by companies that desire that their
fiscal year always end on the same day of the week.
It is a method of managing accounting periods.
It is a common calendar structure for some industries,
such as retail, manufacturing and parking industry.
For more information see:
http://en.wikipedia.org/wiki/4-4-5_calendar
The year may either:
- end on the last X day of the Y month.
- end on the last X day closest to the last day of the Y month.
X is a specific day of the week.
Y is a certain month of the year
Parameters
----------
n : int
weekday : int {0, 1, ..., 6}, default 0
A specific integer for the day of the week.
- 0 is Monday
- 1 is Tuesday
- 2 is Wednesday
- 3 is Thursday
- 4 is Friday
- 5 is Saturday
- 6 is Sunday.
startingMonth : int {1, 2, ... 12}, default 1
The month in which the fiscal year ends.
variation : str, default "nearest"
Method of employing 4-4-5 calendar.
There are two options:
- "nearest" means year end is **weekday** closest to last day of month in year.
- "last" means year end is final **weekday** of the final month in fiscal year.
"""
_prefix = "RE"
_adjust_dst = True
_attributes = frozenset(["weekday", "startingMonth", "variation"])
def __init__(
self, n=1, normalize=False, weekday=0, startingMonth=1, variation="nearest"
):
BaseOffset.__init__(self, n, normalize)
object.__setattr__(self, "startingMonth", startingMonth)
object.__setattr__(self, "weekday", weekday)
object.__setattr__(self, "variation", variation)
if self.n == 0:
raise ValueError("N cannot be 0")
if self.variation not in ["nearest", "last"]:
raise ValueError(f"{self.variation} is not a valid variation")
def is_anchored(self):
return (
self.n == 1 and self.startingMonth is not None and self.weekday is not None
)
def is_on_offset(self, dt):
if self.normalize and not _is_normalized(dt):
return False
dt = datetime(dt.year, dt.month, dt.day)
year_end = self.get_year_end(dt)
if self.variation == "nearest":
# We have to check the year end of "this" cal year AND the previous
return year_end == dt or self.get_year_end(shift_month(dt, -1, None)) == dt
else:
return year_end == dt
@apply_wraps
def apply(self, other):
norm = Timestamp(other).normalize()
n = self.n
prev_year = self.get_year_end(datetime(other.year - 1, self.startingMonth, 1))
cur_year = self.get_year_end(datetime(other.year, self.startingMonth, 1))
next_year = self.get_year_end(datetime(other.year + 1, self.startingMonth, 1))
prev_year = conversion.localize_pydatetime(prev_year, other.tzinfo)
cur_year = conversion.localize_pydatetime(cur_year, other.tzinfo)
next_year = conversion.localize_pydatetime(next_year, other.tzinfo)
# Note: next_year.year == other.year + 1, so we will always
# have other < next_year
if norm == prev_year:
n -= 1
elif norm == cur_year:
pass
elif n > 0:
if norm < prev_year:
n -= 2
elif prev_year < norm < cur_year:
n -= 1
elif cur_year < norm < next_year:
pass
else:
if cur_year < norm < next_year:
n += 1
elif prev_year < norm < cur_year:
pass
elif (
norm.year == prev_year.year
and norm < prev_year
and prev_year - norm <= timedelta(6)
):
# GH#14774, error when next_year.year == cur_year.year
# e.g. prev_year == datetime(2004, 1, 3),
# other == datetime(2004, 1, 1)
n -= 1
else:
assert False
shifted = datetime(other.year + n, self.startingMonth, 1)
result = self.get_year_end(shifted)
result = datetime(
result.year,
result.month,
result.day,
other.hour,
other.minute,
other.second,
other.microsecond,
)
return result
def get_year_end(self, dt):
assert dt.tzinfo is None
dim = ccalendar.get_days_in_month(dt.year, self.startingMonth)
target_date = datetime(dt.year, self.startingMonth, dim)
wkday_diff = self.weekday - target_date.weekday()
if wkday_diff == 0:
# year_end is the same for "last" and "nearest" cases
return target_date
if self.variation == "last":
days_forward = (wkday_diff % 7) - 7
# days_forward is always negative, so we always end up
# in the same year as dt
return target_date + timedelta(days=days_forward)
else:
# variation == "nearest":
days_forward = wkday_diff % 7
if days_forward <= 3:
# The upcoming self.weekday is closer than the previous one
return target_date + timedelta(days_forward)
else:
# The previous self.weekday is closer than the upcoming one
return target_date + timedelta(days_forward - 7)
@property
def rule_code(self):
prefix = self._prefix
suffix = self.get_rule_code_suffix()
return f"{prefix}-{suffix}"
def _get_suffix_prefix(self):
if self.variation == "nearest":
return "N"
else:
return "L"
def get_rule_code_suffix(self):
prefix = self._get_suffix_prefix()
month = ccalendar.MONTH_ALIASES[self.startingMonth]
weekday = ccalendar.int_to_weekday[self.weekday]
return f"{prefix}-{month}-{weekday}"
@classmethod
def _parse_suffix(cls, varion_code, startingMonth_code, weekday_code):
if varion_code == "N":
variation = "nearest"
elif varion_code == "L":
variation = "last"
else:
raise ValueError(f"Unable to parse varion_code: {varion_code}")
startingMonth = ccalendar.MONTH_TO_CAL_NUM[startingMonth_code]
weekday = ccalendar.weekday_to_int[weekday_code]
return {
"weekday": weekday,
"startingMonth": startingMonth,
"variation": variation,
}
@classmethod
def _from_name(cls, *args):
return cls(**cls._parse_suffix(*args))
class FY5253Quarter(DateOffset):
"""
DateOffset increments between business quarter dates
for 52-53 week fiscal year (also known as a 4-4-5 calendar).
It is used by companies that desire that their
fiscal year always end on the same day of the week.
It is a method of managing accounting periods.
It is a common calendar structure for some industries,
such as retail, manufacturing and parking industry.
For more information see:
http://en.wikipedia.org/wiki/4-4-5_calendar
The year may either:
- end on the last X day of the Y month.
- end on the last X day closest to the last day of the Y month.
X is a specific day of the week.
Y is a certain month of the year
startingMonth = 1 corresponds to dates like 1/31/2007, 4/30/2007, ...
startingMonth = 2 corresponds to dates like 2/28/2007, 5/31/2007, ...
startingMonth = 3 corresponds to dates like 3/30/2007, 6/29/2007, ...
Parameters
----------
n : int
weekday : int {0, 1, ..., 6}, default 0
A specific integer for the day of the week.
- 0 is Monday
- 1 is Tuesday
- 2 is Wednesday
- 3 is Thursday
- 4 is Friday
- 5 is Saturday
- 6 is Sunday.
startingMonth : int {1, 2, ..., 12}, default 1
The month in which fiscal years end.
qtr_with_extra_week : int {1, 2, 3, 4}, default 1
The quarter number that has the leap or 14 week when needed.
variation : str, default "nearest"
Method of employing 4-4-5 calendar.
There are two options:
- "nearest" means year end is **weekday** closest to last day of month in year.
- "last" means year end is final **weekday** of the final month in fiscal year.
"""
_prefix = "REQ"
_adjust_dst = True
_attributes = frozenset(
["weekday", "startingMonth", "qtr_with_extra_week", "variation"]
)
def __init__(
self,
n=1,
normalize=False,
weekday=0,
startingMonth=1,
qtr_with_extra_week=1,
variation="nearest",
):
BaseOffset.__init__(self, n, normalize)
object.__setattr__(self, "startingMonth", startingMonth)
object.__setattr__(self, "weekday", weekday)
object.__setattr__(self, "qtr_with_extra_week", qtr_with_extra_week)
object.__setattr__(self, "variation", variation)
if self.n == 0:
raise ValueError("N cannot be 0")
@cache_readonly
def _offset(self):
return FY5253(
startingMonth=self.startingMonth,
weekday=self.weekday,
variation=self.variation,
)
def is_anchored(self):
return self.n == 1 and self._offset.is_anchored()
def _rollback_to_year(self, other):
"""
Roll `other` back to the most recent date that was on a fiscal year
end.
Return the date of that year-end, the number of full quarters
elapsed between that year-end and other, and the remaining Timedelta
since the most recent quarter-end.
Parameters
----------
other : datetime or Timestamp
Returns
-------
tuple of
prev_year_end : Timestamp giving most recent fiscal year end
num_qtrs : int
tdelta : Timedelta
"""
num_qtrs = 0
norm = Timestamp(other).tz_localize(None)
start = self._offset.rollback(norm)
# Note: start <= norm and self._offset.is_on_offset(start)
if start < norm:
# roll adjustment
qtr_lens = self.get_weeks(norm)
# check thet qtr_lens is consistent with self._offset addition
end = liboffsets.shift_day(start, days=7 * sum(qtr_lens))
assert self._offset.is_on_offset(end), (start, end, qtr_lens)
tdelta = norm - start
for qlen in qtr_lens:
if qlen * 7 <= tdelta.days:
num_qtrs += 1
tdelta -= Timedelta(days=qlen * 7)
else:
break
else:
tdelta = Timedelta(0)
# Note: we always have tdelta.value >= 0
return start, num_qtrs, tdelta
@apply_wraps
def apply(self, other):
# Note: self.n == 0 is not allowed.
n = self.n
prev_year_end, num_qtrs, tdelta = self._rollback_to_year(other)
res = prev_year_end
n += num_qtrs
if self.n <= 0 and tdelta.value > 0:
n += 1
# Possible speedup by handling years first.
years = n // 4
if years:
res += self._offset * years
n -= years * 4
# Add an extra day to make *sure* we are getting the quarter lengths
# for the upcoming year, not the previous year
qtr_lens = self.get_weeks(res + Timedelta(days=1))
# Note: we always have 0 <= n < 4
weeks = sum(qtr_lens[:n])
if weeks:
res = liboffsets.shift_day(res, days=weeks * 7)
return res
def get_weeks(self, dt):
ret = [13] * 4
year_has_extra_week = self.year_has_extra_week(dt)
if year_has_extra_week:
ret[self.qtr_with_extra_week - 1] = 14
return ret
def year_has_extra_week(self, dt):
# Avoid round-down errors --> normalize to get
# e.g. '370D' instead of '360D23H'
norm = Timestamp(dt).normalize().tz_localize(None)
next_year_end = self._offset.rollforward(norm)
prev_year_end = norm - self._offset
weeks_in_year = (next_year_end - prev_year_end).days / 7
assert weeks_in_year in [52, 53], weeks_in_year
return weeks_in_year == 53
def is_on_offset(self, dt):
if self.normalize and not _is_normalized(dt):
return False
if self._offset.is_on_offset(dt):
return True
next_year_end = dt - self._offset
qtr_lens = self.get_weeks(dt)
current = next_year_end
for qtr_len in qtr_lens:
current = liboffsets.shift_day(current, days=qtr_len * 7)
if dt == current:
return True
return False
@property
def rule_code(self):
suffix = self._offset.get_rule_code_suffix()
qtr = self.qtr_with_extra_week
return f"{self._prefix}-{suffix}-{qtr}"
@classmethod
def _from_name(cls, *args):
return cls(
**dict(FY5253._parse_suffix(*args[:-1]), qtr_with_extra_week=int(args[-1]))
)
class Easter(DateOffset):
"""
DateOffset for the Easter holiday using logic defined in dateutil.
Right now uses the revised method which is valid in years 1583-4099.
"""
_adjust_dst = True
_attributes = frozenset(["n", "normalize"])
__init__ = BaseOffset.__init__
@apply_wraps
def apply(self, other):
current_easter = easter(other.year)
current_easter = datetime(
current_easter.year, current_easter.month, current_easter.day
)
current_easter = conversion.localize_pydatetime(current_easter, other.tzinfo)
n = self.n
if n >= 0 and other < current_easter:
n -= 1
elif n < 0 and other > current_easter:
n += 1
# TODO: Why does this handle the 0 case the opposite of others?
# NOTE: easter returns a datetime.date so we have to convert to type of
# other
new = easter(other.year + n)
new = datetime(
new.year,
new.month,
new.day,
other.hour,
other.minute,
other.second,
other.microsecond,
)
return new
def is_on_offset(self, dt):
if self.normalize and not _is_normalized(dt):
return False
return date(dt.year, dt.month, dt.day) == easter(dt.year)
# ---------------------------------------------------------------------
# Ticks
def _tick_comp(op):
assert op not in [operator.eq, operator.ne]
def f(self, other):
try:
return op(self.delta, other.delta)
except AttributeError:
# comparing with a non-Tick object
raise TypeError(
f"Invalid comparison between {type(self).__name__} "
f"and {type(other).__name__}"
)
f.__name__ = f"__{op.__name__}__"
return f
class Tick(liboffsets._Tick, SingleConstructorOffset):
_inc = Timedelta(microseconds=1000)
_prefix = "undefined"
_attributes = frozenset(["n", "normalize"])
def __init__(self, n=1, normalize=False):
BaseOffset.__init__(self, n, normalize)
if normalize:
raise ValueError(
"Tick offset with `normalize=True` are not allowed."
) # GH#21427
__gt__ = _tick_comp(operator.gt)
__ge__ = _tick_comp(operator.ge)
__lt__ = _tick_comp(operator.lt)
__le__ = _tick_comp(operator.le)
def __add__(self, other):
if isinstance(other, Tick):
if type(self) == type(other):
return type(self)(self.n + other.n)
else:
return _delta_to_tick(self.delta + other.delta)
elif isinstance(other, Period):
return other + self
try:
return self.apply(other)
except ApplyTypeError:
return NotImplemented
except OverflowError:
raise OverflowError(
f"the add operation between {self} and {other} will overflow"
)
def __eq__(self, other: Any) -> bool:
if isinstance(other, str):
from pandas.tseries.frequencies import to_offset
try:
# GH#23524 if to_offset fails, we are dealing with an
# incomparable type so == is False and != is True
other = to_offset(other)
except ValueError:
# e.g. "infer"
return False
if isinstance(other, Tick):
return self.delta == other.delta
else:
return False
# This is identical to DateOffset.__hash__, but has to be redefined here
# for Python 3, because we've redefined __eq__.
def __hash__(self):
return hash(self._params)
def __ne__(self, other):
if isinstance(other, str):
from pandas.tseries.frequencies import to_offset
try:
# GH#23524 if to_offset fails, we are dealing with an
# incomparable type so == is False and != is True
other = to_offset(other)
except ValueError:
# e.g. "infer"
return True
if isinstance(other, Tick):
return self.delta != other.delta
else:
return True
@property
def delta(self):
return self.n * self._inc
@property
def nanos(self):
return delta_to_nanoseconds(self.delta)
# TODO: Should Tick have its own apply_index?
def apply(self, other):
# Timestamp can handle tz and nano sec, thus no need to use apply_wraps
if isinstance(other, Timestamp):
# GH 15126
# in order to avoid a recursive
# call of __add__ and __radd__ if there is
# an exception, when we call using the + operator,
# we directly call the known method
result = other.__add__(self)
if result is NotImplemented:
raise OverflowError
return result
elif isinstance(other, (datetime, np.datetime64, date)):
return as_timestamp(other) + self
if isinstance(other, timedelta):
return other + self.delta
elif isinstance(other, type(self)):
return type(self)(self.n + other.n)
raise ApplyTypeError(f"Unhandled type: {type(other).__name__}")
def is_anchored(self):
return False
def _delta_to_tick(delta):
if delta.microseconds == 0 and getattr(delta, "nanoseconds", 0) == 0:
# nanoseconds only for pd.Timedelta
if delta.seconds == 0:
return Day(delta.days)
else:
seconds = delta.days * 86400 + delta.seconds
if seconds % 3600 == 0:
return Hour(seconds / 3600)
elif seconds % 60 == 0:
return Minute(seconds / 60)
else:
return Second(seconds)
else:
nanos = delta_to_nanoseconds(delta)
if nanos % 1000000 == 0:
return Milli(nanos // 1000000)
elif nanos % 1000 == 0:
return Micro(nanos // 1000)
else: # pragma: no cover
return Nano(nanos)
class Day(Tick):
_inc = Timedelta(days=1)
_prefix = "D"
class Hour(Tick):
_inc = Timedelta(hours=1)
_prefix = "H"
class Minute(Tick):
_inc = Timedelta(minutes=1)
_prefix = "T"
class Second(Tick):
_inc = Timedelta(seconds=1)
_prefix = "S"
class Milli(Tick):
_inc = Timedelta(milliseconds=1)
_prefix = "L"
class Micro(Tick):
_inc = Timedelta(microseconds=1)
_prefix = "U"
class Nano(Tick):
_inc = Timedelta(nanoseconds=1)
_prefix = "N"
BDay = BusinessDay
BMonthEnd = BusinessMonthEnd
BMonthBegin = BusinessMonthBegin
CBMonthEnd = CustomBusinessMonthEnd
CBMonthBegin = CustomBusinessMonthBegin
CDay = CustomBusinessDay
# ---------------------------------------------------------------------
def generate_range(start=None, end=None, periods=None, offset=BDay()):
"""
Generates a sequence of dates corresponding to the specified time
offset. Similar to dateutil.rrule except uses pandas DateOffset
objects to represent time increments.
Parameters
----------
start : datetime, (default None)
end : datetime, (default None)
periods : int, (default None)
offset : DateOffset, (default BDay())
Notes
-----
* This method is faster for generating weekdays than dateutil.rrule
* At least two of (start, end, periods) must be specified.
* If both start and end are specified, the returned dates will
satisfy start <= date <= end.
Returns
-------
dates : generator object
"""
from pandas.tseries.frequencies import to_offset
offset = to_offset(offset)
start = Timestamp(start)
start = start if start is not NaT else None
end = Timestamp(end)
end = end if end is not NaT else None
if start and not offset.is_on_offset(start):
start = offset.rollforward(start)
elif end and not offset.is_on_offset(end):
end = offset.rollback(end)
if periods is None and end < start and offset.n >= 0:
end = None
periods = 0
if end is None:
end = start + (periods - 1) * offset
if start is None:
start = end - (periods - 1) * offset
cur = start
if offset.n >= 0:
while cur <= end:
yield cur
if cur == end:
# GH#24252 avoid overflows by not performing the addition
# in offset.apply unless we have to
break
# faster than cur + offset
next_date = offset.apply(cur)
if next_date <= cur:
raise ValueError(f"Offset {offset} did not increment date")
cur = next_date
else:
while cur >= end:
yield cur
if cur == end:
# GH#24252 avoid overflows by not performing the addition
# in offset.apply unless we have to
break
# faster than cur + offset
next_date = offset.apply(cur)
if next_date >= cur:
raise ValueError(f"Offset {offset} did not decrement date")
cur = next_date
prefix_mapping = {
offset._prefix: offset
for offset in [
YearBegin, # 'AS'
YearEnd, # 'A'
BYearBegin, # 'BAS'
BYearEnd, # 'BA'
BusinessDay, # 'B'
BusinessMonthBegin, # 'BMS'
BusinessMonthEnd, # 'BM'
BQuarterEnd, # 'BQ'
BQuarterBegin, # 'BQS'
BusinessHour, # 'BH'
CustomBusinessDay, # 'C'
CustomBusinessMonthEnd, # 'CBM'
CustomBusinessMonthBegin, # 'CBMS'
CustomBusinessHour, # 'CBH'
MonthEnd, # 'M'
MonthBegin, # 'MS'
Nano, # 'N'
SemiMonthEnd, # 'SM'
SemiMonthBegin, # 'SMS'
Week, # 'W'
Second, # 'S'
Minute, # 'T'
Micro, # 'U'
QuarterEnd, # 'Q'
QuarterBegin, # 'QS'
Milli, # 'L'
Hour, # 'H'
Day, # 'D'
WeekOfMonth, # 'WOM'
FY5253,
FY5253Quarter,
]
}
from datetime import date, datetime, timedelta
import functools
import operator
from typing import Any, Optional
import warnings
from dateutil.easter import easter
import numpy as np
from pandas._libs.tslibs import (
NaT,
OutOfBoundsDatetime,
Period,
Timedelta,
Timestamp,
ccalendar,
conversion,
delta_to_nanoseconds,
frequencies as libfrequencies,
normalize_date,
offsets as liboffsets,
timezones,
)
from pandas._libs.tslibs.offsets import (
ApplyTypeError,
BaseOffset,
_get_calendar,
_is_normalized,
_to_dt64,
apply_index_wraps,
as_datetime,
roll_yearday,
shift_month,
)
from pandas.errors import AbstractMethodError
from pandas.util._decorators import Appender, Substitution, cache_readonly
from pandas.core.dtypes.inference import is_list_like
__all__ = [
"Day",
"BusinessDay",
"BDay",
"CustomBusinessDay",
"CDay",
"CBMonthEnd",
"CBMonthBegin",
"MonthBegin",
"BMonthBegin",
"MonthEnd",
"BMonthEnd",
"SemiMonthEnd",
"SemiMonthBegin",
"BusinessHour",
"CustomBusinessHour",
"YearBegin",
"BYearBegin",
"YearEnd",
"BYearEnd",
"QuarterBegin",
"BQuarterBegin",
"QuarterEnd",
"BQuarterEnd",
"LastWeekOfMonth",
"FY5253Quarter",
"FY5253",
"Week",
"WeekOfMonth",
"Easter",
"Hour",
"Minute",
"Second",
"Milli",
"Micro",
"Nano",
"DateOffset",
]
# convert to/from datetime/timestamp to allow invalid Timestamp ranges to
# pass thru
def as_timestamp(obj):
if isinstance(obj, Timestamp):
return obj
try:
return Timestamp(obj)
except (OutOfBoundsDatetime):
pass
return obj
def apply_wraps(func):
@functools.wraps(func)
def wrapper(self, other):
if other is NaT:
return NaT
elif isinstance(other, (timedelta, Tick, DateOffset)):
# timedelta path
return func(self, other)
elif isinstance(other, (np.datetime64, datetime, date)):
other = as_timestamp(other)
tz = getattr(other, "tzinfo", None)
nano = getattr(other, "nanosecond", 0)
try:
if self._adjust_dst and isinstance(other, Timestamp):
other = other.tz_localize(None)
result = func(self, other)
if self._adjust_dst:
result = conversion.localize_pydatetime(result, tz)
result = Timestamp(result)
if self.normalize:
result = result.normalize()
# nanosecond may be deleted depending on offset process
if not self.normalize and nano != 0:
if not isinstance(self, Nano) and result.nanosecond != nano:
if result.tz is not None:
# convert to UTC
value = conversion.tz_convert_single(
result.value, timezones.UTC, result.tz
)
else:
value = result.value
result = Timestamp(value + nano)
if tz is not None and result.tzinfo is None:
result = conversion.localize_pydatetime(result, tz)
except OutOfBoundsDatetime:
result = func(self, as_datetime(other))
if self.normalize:
# normalize_date returns normal datetime
result = normalize_date(result)
if tz is not None and result.tzinfo is None:
result = conversion.localize_pydatetime(result, tz)
result = Timestamp(result)
return result
return wrapper
# ---------------------------------------------------------------------
# DateOffset
class DateOffset(BaseOffset):
"""
Standard kind of date increment used for a date range.
Works exactly like relativedelta in terms of the keyword args you
pass in, use of the keyword n is discouraged-- you would be better
off specifying n in the keywords you use, but regardless it is
there for you. n is needed for DateOffset subclasses.
DateOffset work as follows. Each offset specify a set of dates
that conform to the DateOffset. For example, Bday defines this
set to be the set of dates that are weekdays (M-F). To test if a
date is in the set of a DateOffset dateOffset we can use the
is_on_offset method: dateOffset.is_on_offset(date).
If a date is not on a valid date, the rollback and rollforward
methods can be used to roll the date to the nearest valid date
before/after the date.
DateOffsets can be created to move dates forward a given number of
valid dates. For example, Bday(2) can be added to a date to move
it two business days forward. If the date does not start on a
valid date, first it is moved to a valid date. Thus pseudo code
is:
def __add__(date):
date = rollback(date) # does nothing if date is valid
return date + <n number of periods>
When a date offset is created for a negative number of periods,
the date is first rolled forward. The pseudo code is:
def __add__(date):
date = rollforward(date) # does nothing is date is valid
return date + <n number of periods>
Zero presents a problem. Should it roll forward or back? We
arbitrarily have it rollforward:
date + BDay(0) == BDay.rollforward(date)
Since 0 is a bit weird, we suggest avoiding its use.
Parameters
----------
n : int, default 1
The number of time periods the offset represents.
normalize : bool, default False
Whether to round the result of a DateOffset addition down to the
previous midnight.
**kwds
Temporal parameter that add to or replace the offset value.
Parameters that **add** to the offset (like Timedelta):
- years
- months
- weeks
- days
- hours
- minutes
- seconds
- microseconds
- nanoseconds
Parameters that **replace** the offset value:
- year
- month
- day
- weekday
- hour
- minute
- second
- microsecond
- nanosecond.
See Also
--------
dateutil.relativedelta.relativedelta : The relativedelta type is designed
to be applied to an existing datetime an can replace specific components of
that datetime, or represents an interval of time.
Examples
--------
>>> from pandas.tseries.offsets import DateOffset
>>> ts = pd.Timestamp('2017-01-01 09:10:11')
>>> ts + DateOffset(months=3)
Timestamp('2017-04-01 09:10:11')
>>> ts = pd.Timestamp('2017-01-01 09:10:11')
>>> ts + DateOffset(months=2)
Timestamp('2017-03-01 09:10:11')
"""
_params = cache_readonly(BaseOffset._params.fget)
_use_relativedelta = False
_adjust_dst = False
_attributes = frozenset(["n", "normalize"] + list(liboffsets.relativedelta_kwds))
_deprecations = frozenset(["isAnchored", "onOffset"])
# default for prior pickles
normalize = False
def __init__(self, n=1, normalize=False, **kwds):
BaseOffset.__init__(self, n, normalize)
off, use_rd = liboffsets._determine_offset(kwds)
object.__setattr__(self, "_offset", off)
object.__setattr__(self, "_use_relativedelta", use_rd)
for key in kwds:
val = kwds[key]
object.__setattr__(self, key, val)
@apply_wraps
def apply(self, other):
if self._use_relativedelta:
other = as_datetime(other)
if len(self.kwds) > 0:
tzinfo = getattr(other, "tzinfo", None)
if tzinfo is not None and self._use_relativedelta:
# perform calculation in UTC
other = other.replace(tzinfo=None)
if self.n > 0:
for i in range(self.n):
other = other + self._offset
else:
for i in range(-self.n):
other = other - self._offset
if tzinfo is not None and self._use_relativedelta:
# bring tz back from UTC calculation
other = conversion.localize_pydatetime(other, tzinfo)
return as_timestamp(other)
else:
return other + timedelta(self.n)
@apply_index_wraps
def apply_index(self, i):
"""
Vectorized apply of DateOffset to DatetimeIndex,
raises NotImplentedError for offsets without a
vectorized implementation.
Parameters
----------
i : DatetimeIndex
Returns
-------
y : DatetimeIndex
"""
if type(self) is not DateOffset:
raise NotImplementedError(
f"DateOffset subclass {type(self).__name__} "
"does not have a vectorized implementation"
)
kwds = self.kwds
relativedelta_fast = {
"years",
"months",
"weeks",
"days",
"hours",
"minutes",
"seconds",
"microseconds",
}
# relativedelta/_offset path only valid for base DateOffset
if self._use_relativedelta and set(kwds).issubset(relativedelta_fast):
months = (kwds.get("years", 0) * 12 + kwds.get("months", 0)) * self.n
if months:
shifted = liboffsets.shift_months(i.asi8, months)
i = type(i)(shifted, dtype=i.dtype)
weeks = (kwds.get("weeks", 0)) * self.n
if weeks:
# integer addition on PeriodIndex is deprecated,
# so we directly use _time_shift instead
asper = i.to_period("W")
if not isinstance(asper._data, np.ndarray):
# unwrap PeriodIndex --> PeriodArray
asper = asper._data
shifted = asper._time_shift(weeks)
i = shifted.to_timestamp() + i.to_perioddelta("W")
timedelta_kwds = {
k: v
for k, v in kwds.items()
if k in ["days", "hours", "minutes", "seconds", "microseconds"]
}
if timedelta_kwds:
delta = Timedelta(**timedelta_kwds)
i = i + (self.n * delta)
return i
elif not self._use_relativedelta and hasattr(self, "_offset"):
# timedelta
return i + (self._offset * self.n)
else:
# relativedelta with other keywords
kwd = set(kwds) - relativedelta_fast
raise NotImplementedError(
"DateOffset with relativedelta "
f"keyword(s) {kwd} not able to be "
"applied vectorized"
)
def is_anchored(self):
# TODO: Does this make sense for the general case? It would help
# if there were a canonical docstring for what is_anchored means.
return self.n == 1
def onOffset(self, dt):
warnings.warn(
"onOffset is a deprecated, use is_on_offset instead",
FutureWarning,
stacklevel=2,
)
return self.is_on_offset(dt)
def isAnchored(self):
warnings.warn(
"isAnchored is a deprecated, use is_anchored instead",
FutureWarning,
stacklevel=2,
)
return self.is_anchored()
# TODO: Combine this with BusinessMixin version by defining a whitelisted
# set of attributes on each object rather than the existing behavior of
# iterating over internal ``__dict__``
def _repr_attrs(self):
exclude = {"n", "inc", "normalize"}
attrs = []
for attr in sorted(self.__dict__):
if attr.startswith("_") or attr == "kwds":
continue
elif attr not in exclude:
value = getattr(self, attr)
attrs.append(f"{attr}={value}")
out = ""
if attrs:
out += ": " + ", ".join(attrs)
return out
@property
def name(self):
return self.rule_code
def rollback(self, dt):
"""
Roll provided date backward to next offset only if not on offset.
Returns
-------
TimeStamp
Rolled timestamp if not on offset, otherwise unchanged timestamp.
"""
dt = as_timestamp(dt)
if not self.is_on_offset(dt):
dt = dt - type(self)(1, normalize=self.normalize, **self.kwds)
return dt
def rollforward(self, dt):
"""
Roll provided date forward to next offset only if not on offset.
Returns
-------
TimeStamp
Rolled timestamp if not on offset, otherwise unchanged timestamp.
"""
dt = as_timestamp(dt)
if not self.is_on_offset(dt):
dt = dt + type(self)(1, normalize=self.normalize, **self.kwds)
return dt
def is_on_offset(self, dt):
if self.normalize and not _is_normalized(dt):
return False
# XXX, see #1395
if type(self) == DateOffset or isinstance(self, Tick):
return True
# Default (slow) method for determining if some date is a member of the
# date range generated by this offset. Subclasses may have this
# re-implemented in a nicer way.
a = dt
b = (dt + self) - self
return a == b
# way to get around weirdness with rule_code
@property
def _prefix(self):
raise NotImplementedError("Prefix not defined")
@property
def rule_code(self):
return self._prefix
@cache_readonly
def freqstr(self):
try:
code = self.rule_code
except NotImplementedError:
return repr(self)
if self.n != 1:
fstr = f"{self.n}{code}"
else:
fstr = code
try:
if self._offset:
fstr += self._offset_str()
except AttributeError:
# TODO: standardize `_offset` vs `offset` naming convention
pass
return fstr
def _offset_str(self):
return ""
@property
def nanos(self):
raise ValueError(f"{self} is a non-fixed frequency")
class SingleConstructorOffset(DateOffset):
@classmethod
def _from_name(cls, suffix=None):
# default _from_name calls cls with no args
if suffix:
raise ValueError(f"Bad freq suffix {suffix}")
return cls()
class _CustomMixin:
"""
Mixin for classes that define and validate calendar, holidays,
and weekdays attributes.
"""
def __init__(self, weekmask, holidays, calendar):
calendar, holidays = _get_calendar(
weekmask=weekmask, holidays=holidays, calendar=calendar
)
# Custom offset instances are identified by the
# following two attributes. See DateOffset._params()
# holidays, weekmask
object.__setattr__(self, "weekmask", weekmask)
object.__setattr__(self, "holidays", holidays)
object.__setattr__(self, "calendar", calendar)
class BusinessMixin:
"""
Mixin to business types to provide related functions.
"""
@property
def offset(self):
"""
Alias for self._offset.
"""
# Alias for backward compat
return self._offset
def _repr_attrs(self):
if self.offset:
attrs = [f"offset={repr(self.offset)}"]
else:
attrs = None
out = ""
if attrs:
out += ": " + ", ".join(attrs)
return out
class BusinessDay(BusinessMixin, SingleConstructorOffset):
"""
DateOffset subclass representing possibly n business days.
"""
_prefix = "B"
_adjust_dst = True
_attributes = frozenset(["n", "normalize", "offset"])
def __init__(self, n=1, normalize=False, offset=timedelta(0)):
BaseOffset.__init__(self, n, normalize)
object.__setattr__(self, "_offset", offset)
def _offset_str(self):
def get_str(td):
off_str = ""
if td.days > 0:
off_str += str(td.days) + "D"
if td.seconds > 0:
s = td.seconds
hrs = int(s / 3600)
if hrs != 0:
off_str += str(hrs) + "H"
s -= hrs * 3600
mts = int(s / 60)
if mts != 0:
off_str += str(mts) + "Min"
s -= mts * 60
if s != 0:
off_str += str(s) + "s"
if td.microseconds > 0:
off_str += str(td.microseconds) + "us"
return off_str
if isinstance(self.offset, timedelta):
zero = timedelta(0, 0, 0)
if self.offset >= zero:
off_str = "+" + get_str(self.offset)
else:
off_str = "-" + get_str(-self.offset)
return off_str
else:
return "+" + repr(self.offset)
@apply_wraps
def apply(self, other):
if isinstance(other, datetime):
n = self.n
wday = other.weekday()
# avoid slowness below by operating on weeks first
weeks = n // 5
if n <= 0 and wday > 4:
# roll forward
n += 1
n -= 5 * weeks
# n is always >= 0 at this point
if n == 0 and wday > 4:
# roll back
days = 4 - wday
elif wday > 4:
# roll forward
days = (7 - wday) + (n - 1)
elif wday + n <= 4:
# shift by n days without leaving the current week
days = n
else:
# shift by n days plus 2 to get past the weekend
days = n + 2
result = other + timedelta(days=7 * weeks + days)
if self.offset:
result = result + self.offset
return result
elif isinstance(other, (timedelta, Tick)):
return BDay(self.n, offset=self.offset + other, normalize=self.normalize)
else:
raise ApplyTypeError(
"Only know how to combine business day with datetime or timedelta."
)
@apply_index_wraps
def apply_index(self, i):
time = i.to_perioddelta("D")
# to_period rolls forward to next BDay; track and
# reduce n where it does when rolling forward
asper = i.to_period("B")
if not isinstance(asper._data, np.ndarray):
# unwrap PeriodIndex --> PeriodArray
asper = asper._data
if self.n > 0:
shifted = (i.to_perioddelta("B") - time).asi8 != 0
# Integer-array addition is deprecated, so we use
# _time_shift directly
roll = np.where(shifted, self.n - 1, self.n)
shifted = asper._addsub_int_array(roll, operator.add)
else:
# Integer addition is deprecated, so we use _time_shift directly
roll = self.n
shifted = asper._time_shift(roll)
result = shifted.to_timestamp() + time
return result
def is_on_offset(self, dt):
if self.normalize and not _is_normalized(dt):
return False
return dt.weekday() < 5
class BusinessHourMixin(BusinessMixin):
def __init__(self, start="09:00", end="17:00", offset=timedelta(0)):
# must be validated here to equality check
if not is_list_like(start):
start = [start]
if not len(start):
raise ValueError("Must include at least 1 start time")
if not is_list_like(end):
end = [end]
if not len(end):
raise ValueError("Must include at least 1 end time")
start = np.array([liboffsets._validate_business_time(x) for x in start])
end = np.array([liboffsets._validate_business_time(x) for x in end])
# Validation of input
if len(start) != len(end):
raise ValueError("number of starting time and ending time must be the same")
num_openings = len(start)
# sort starting and ending time by starting time
index = np.argsort(start)
# convert to tuple so that start and end are hashable
start = tuple(start[index])
end = tuple(end[index])
total_secs = 0
for i in range(num_openings):
total_secs += self._get_business_hours_by_sec(start[i], end[i])
total_secs += self._get_business_hours_by_sec(
end[i], start[(i + 1) % num_openings]
)
if total_secs != 24 * 60 * 60:
raise ValueError(
"invalid starting and ending time(s): "
"opening hours should not touch or overlap with "
"one another"
)
object.__setattr__(self, "start", start)
object.__setattr__(self, "end", end)
object.__setattr__(self, "_offset", offset)
@cache_readonly
def next_bday(self):
"""
Used for moving to next business day.
"""
if self.n >= 0:
nb_offset = 1
else:
nb_offset = -1
if self._prefix.startswith("C"):
# CustomBusinessHour
return CustomBusinessDay(
n=nb_offset,
weekmask=self.weekmask,
holidays=self.holidays,
calendar=self.calendar,
)
else:
return BusinessDay(n=nb_offset)
def _next_opening_time(self, other, sign=1):
"""
If self.n and sign have the same sign, return the earliest opening time
later than or equal to current time.
Otherwise the latest opening time earlier than or equal to current
time.
Opening time always locates on BusinessDay.
However, closing time may not if business hour extends over midnight.
Parameters
----------
other : datetime
Current time.
sign : int, default 1.
Either 1 or -1. Going forward in time if it has the same sign as
self.n. Going backward in time otherwise.
Returns
-------
result : datetime
Next opening time.
"""
earliest_start = self.start[0]
latest_start = self.start[-1]
if not self.next_bday.is_on_offset(other):
# today is not business day
other = other + sign * self.next_bday
if self.n * sign >= 0:
hour, minute = earliest_start.hour, earliest_start.minute
else:
hour, minute = latest_start.hour, latest_start.minute
else:
if self.n * sign >= 0:
if latest_start < other.time():
# current time is after latest starting time in today
other = other + sign * self.next_bday
hour, minute = earliest_start.hour, earliest_start.minute
else:
# find earliest starting time no earlier than current time
for st in self.start:
if other.time() <= st:
hour, minute = st.hour, st.minute
break
else:
if other.time() < earliest_start:
# current time is before earliest starting time in today
other = other + sign * self.next_bday
hour, minute = latest_start.hour, latest_start.minute
else:
# find latest starting time no later than current time
for st in reversed(self.start):
if other.time() >= st:
hour, minute = st.hour, st.minute
break
return datetime(other.year, other.month, other.day, hour, minute)
def _prev_opening_time(self, other):
"""
If n is positive, return the latest opening time earlier than or equal
to current time.
Otherwise the earliest opening time later than or equal to current
time.
Parameters
----------
other : datetime
Current time.
Returns
-------
result : datetime
Previous opening time.
"""
return self._next_opening_time(other, sign=-1)
def _get_business_hours_by_sec(self, start, end):
"""
Return business hours in a day by seconds.
"""
# create dummy datetime to calculate businesshours in a day
dtstart = datetime(2014, 4, 1, start.hour, start.minute)
day = 1 if start < end else 2
until = datetime(2014, 4, day, end.hour, end.minute)
return int((until - dtstart).total_seconds())
@apply_wraps
def rollback(self, dt):
"""
Roll provided date backward to next offset only if not on offset.
"""
if not self.is_on_offset(dt):
if self.n >= 0:
dt = self._prev_opening_time(dt)
else:
dt = self._next_opening_time(dt)
return self._get_closing_time(dt)
return dt
@apply_wraps
def rollforward(self, dt):
"""
Roll provided date forward to next offset only if not on offset.
"""
if not self.is_on_offset(dt):
if self.n >= 0:
return self._next_opening_time(dt)
else:
return self._prev_opening_time(dt)
return dt
def _get_closing_time(self, dt):
"""
Get the closing time of a business hour interval by its opening time.
Parameters
----------
dt : datetime
Opening time of a business hour interval.
Returns
-------
result : datetime
Corresponding closing time.
"""
for i, st in enumerate(self.start):
if st.hour == dt.hour and st.minute == dt.minute:
return dt + timedelta(
seconds=self._get_business_hours_by_sec(st, self.end[i])
)
assert False
@apply_wraps
def apply(self, other):
if isinstance(other, datetime):
# used for detecting edge condition
nanosecond = getattr(other, "nanosecond", 0)
# reset timezone and nanosecond
# other may be a Timestamp, thus not use replace
other = datetime(
other.year,
other.month,
other.day,
other.hour,
other.minute,
other.second,
other.microsecond,
)
n = self.n
# adjust other to reduce number of cases to handle
if n >= 0:
if other.time() in self.end or not self._is_on_offset(other):
other = self._next_opening_time(other)
else:
if other.time() in self.start:
# adjustment to move to previous business day
other = other - timedelta(seconds=1)
if not self._is_on_offset(other):
other = self._next_opening_time(other)
other = self._get_closing_time(other)
# get total business hours by sec in one business day
businesshours = sum(
self._get_business_hours_by_sec(st, en)
for st, en in zip(self.start, self.end)
)
bd, r = divmod(abs(n * 60), businesshours // 60)
if n < 0:
bd, r = -bd, -r
# adjust by business days first
if bd != 0:
if isinstance(self, _CustomMixin): # GH 30593
skip_bd = CustomBusinessDay(
n=bd,
weekmask=self.weekmask,
holidays=self.holidays,
calendar=self.calendar,
)
else:
skip_bd = BusinessDay(n=bd)
# midnight business hour may not on BusinessDay
if not self.next_bday.is_on_offset(other):
prev_open = self._prev_opening_time(other)
remain = other - prev_open
other = prev_open + skip_bd + remain
else:
other = other + skip_bd
# remaining business hours to adjust
bhour_remain = timedelta(minutes=r)
if n >= 0:
while bhour_remain != timedelta(0):
# business hour left in this business time interval
bhour = (
self._get_closing_time(self._prev_opening_time(other)) - other
)
if bhour_remain < bhour:
# finish adjusting if possible
other += bhour_remain
bhour_remain = timedelta(0)
else:
# go to next business time interval
bhour_remain -= bhour
other = self._next_opening_time(other + bhour)
else:
while bhour_remain != timedelta(0):
# business hour left in this business time interval
bhour = self._next_opening_time(other) - other
if (
bhour_remain > bhour
or bhour_remain == bhour
and nanosecond != 0
):
# finish adjusting if possible
other += bhour_remain
bhour_remain = timedelta(0)
else:
# go to next business time interval
bhour_remain -= bhour
other = self._get_closing_time(
self._next_opening_time(
other + bhour - timedelta(seconds=1)
)
)
return other
else:
raise ApplyTypeError("Only know how to combine business hour with datetime")
def is_on_offset(self, dt):
if self.normalize and not _is_normalized(dt):
return False
if dt.tzinfo is not None:
dt = datetime(
dt.year, dt.month, dt.day, dt.hour, dt.minute, dt.second, dt.microsecond
)
# Valid BH can be on the different BusinessDay during midnight
# Distinguish by the time spent from previous opening time
return self._is_on_offset(dt)
def _is_on_offset(self, dt):
"""
Slight speedups using calculated values.
"""
# if self.normalize and not _is_normalized(dt):
# return False
# Valid BH can be on the different BusinessDay during midnight
# Distinguish by the time spent from previous opening time
if self.n >= 0:
op = self._prev_opening_time(dt)
else:
op = self._next_opening_time(dt)
span = (dt - op).total_seconds()
businesshours = 0
for i, st in enumerate(self.start):
if op.hour == st.hour and op.minute == st.minute:
businesshours = self._get_business_hours_by_sec(st, self.end[i])
if span <= businesshours:
return True
else:
return False
def _repr_attrs(self):
out = super()._repr_attrs()
hours = ",".join(
f'{st.strftime("%H:%M")}-{en.strftime("%H:%M")}'
for st, en in zip(self.start, self.end)
)
attrs = [f"{self._prefix}={hours}"]
out += ": " + ", ".join(attrs)
return out
class BusinessHour(BusinessHourMixin, SingleConstructorOffset):
"""
DateOffset subclass representing possibly n business hours.
"""
_prefix = "BH"
_anchor = 0
_attributes = frozenset(["n", "normalize", "start", "end", "offset"])
def __init__(
self, n=1, normalize=False, start="09:00", end="17:00", offset=timedelta(0)
):
BaseOffset.__init__(self, n, normalize)
super().__init__(start=start, end=end, offset=offset)
class CustomBusinessDay(_CustomMixin, BusinessDay):
"""
DateOffset subclass representing possibly n custom business days,
excluding holidays.
Parameters
----------
n : int, default 1
normalize : bool, default False
Normalize start/end dates to midnight before generating date range.
weekmask : str, Default 'Mon Tue Wed Thu Fri'
Weekmask of valid business days, passed to ``numpy.busdaycalendar``.
holidays : list
List/array of dates to exclude from the set of valid business days,
passed to ``numpy.busdaycalendar``.
calendar : pd.HolidayCalendar or np.busdaycalendar
offset : timedelta, default timedelta(0)
"""
_prefix = "C"
_attributes = frozenset(
["n", "normalize", "weekmask", "holidays", "calendar", "offset"]
)
def __init__(
self,
n=1,
normalize=False,
weekmask="Mon Tue Wed Thu Fri",
holidays=None,
calendar=None,
offset=timedelta(0),
):
BaseOffset.__init__(self, n, normalize)
object.__setattr__(self, "_offset", offset)
_CustomMixin.__init__(self, weekmask, holidays, calendar)
@apply_wraps
def apply(self, other):
if self.n <= 0:
roll = "forward"
else:
roll = "backward"
if isinstance(other, datetime):
date_in = other
np_dt = np.datetime64(date_in.date())
np_incr_dt = np.busday_offset(
np_dt, self.n, roll=roll, busdaycal=self.calendar
)
dt_date = np_incr_dt.astype(datetime)
result = datetime.combine(dt_date, date_in.time())
if self.offset:
result = result + self.offset
return result
elif isinstance(other, (timedelta, Tick)):
return BDay(self.n, offset=self.offset + other, normalize=self.normalize)
else:
raise ApplyTypeError(
"Only know how to combine trading day with "
"datetime, datetime64 or timedelta."
)
def apply_index(self, i):
raise NotImplementedError
def is_on_offset(self, dt):
if self.normalize and not _is_normalized(dt):
return False
day64 = _to_dt64(dt, "datetime64[D]")
return np.is_busday(day64, busdaycal=self.calendar)
class CustomBusinessHour(_CustomMixin, BusinessHourMixin, SingleConstructorOffset):
"""
DateOffset subclass representing possibly n custom business days.
"""
_prefix = "CBH"
_anchor = 0
_attributes = frozenset(
["n", "normalize", "weekmask", "holidays", "calendar", "start", "end", "offset"]
)
def __init__(
self,
n=1,
normalize=False,
weekmask="Mon Tue Wed Thu Fri",
holidays=None,
calendar=None,
start="09:00",
end="17:00",
offset=timedelta(0),
):
BaseOffset.__init__(self, n, normalize)
object.__setattr__(self, "_offset", offset)
_CustomMixin.__init__(self, weekmask, holidays, calendar)
BusinessHourMixin.__init__(self, start=start, end=end, offset=offset)
# ---------------------------------------------------------------------
# Month-Based Offset Classes
class MonthOffset(SingleConstructorOffset):
_adjust_dst = True
_attributes = frozenset(["n", "normalize"])
__init__ = BaseOffset.__init__
@property
def name(self):
if self.is_anchored:
return self.rule_code
else:
month = ccalendar.MONTH_ALIASES[self.n]
return f"{self.code_rule}-{month}"
def is_on_offset(self, dt):
if self.normalize and not _is_normalized(dt):
return False
return dt.day == self._get_offset_day(dt)
@apply_wraps
def apply(self, other):
compare_day = self._get_offset_day(other)
n = liboffsets.roll_convention(other.day, self.n, compare_day)
return shift_month(other, n, self._day_opt)
@apply_index_wraps
def apply_index(self, i):
shifted = liboffsets.shift_months(i.asi8, self.n, self._day_opt)
# TODO: going through __new__ raises on call to _validate_frequency;
# are we passing incorrect freq?
return type(i)._simple_new(shifted, freq=i.freq, dtype=i.dtype)
class MonthEnd(MonthOffset):
"""
DateOffset of one month end.
"""
_prefix = "M"
_day_opt = "end"
class MonthBegin(MonthOffset):
"""
DateOffset of one month at beginning.
"""
_prefix = "MS"
_day_opt = "start"
class BusinessMonthEnd(MonthOffset):
"""
DateOffset increments between business EOM dates.
"""
_prefix = "BM"
_day_opt = "business_end"
class BusinessMonthBegin(MonthOffset):
"""
DateOffset of one business month at beginning.
"""
_prefix = "BMS"
_day_opt = "business_start"
class _CustomBusinessMonth(_CustomMixin, BusinessMixin, MonthOffset):
"""
DateOffset subclass representing custom business month(s).
Increments between %(bound)s of month dates.
Parameters
----------
n : int, default 1
The number of months represented.
normalize : bool, default False
Normalize start/end dates to midnight before generating date range.
weekmask : str, Default 'Mon Tue Wed Thu Fri'
Weekmask of valid business days, passed to ``numpy.busdaycalendar``.
holidays : list
List/array of dates to exclude from the set of valid business days,
passed to ``numpy.busdaycalendar``.
calendar : pd.HolidayCalendar or np.busdaycalendar
Calendar to integrate.
offset : timedelta, default timedelta(0)
Time offset to apply.
"""
_attributes = frozenset(
["n", "normalize", "weekmask", "holidays", "calendar", "offset"]
)
is_on_offset = DateOffset.is_on_offset # override MonthOffset method
apply_index = DateOffset.apply_index # override MonthOffset method
def __init__(
self,
n=1,
normalize=False,
weekmask="Mon Tue Wed Thu Fri",
holidays=None,
calendar=None,
offset=timedelta(0),
):
BaseOffset.__init__(self, n, normalize)
object.__setattr__(self, "_offset", offset)
_CustomMixin.__init__(self, weekmask, holidays, calendar)
@cache_readonly
def cbday_roll(self):
"""
Define default roll function to be called in apply method.
"""
cbday = CustomBusinessDay(n=self.n, normalize=False, **self.kwds)
if self._prefix.endswith("S"):
# MonthBegin
roll_func = cbday.rollforward
else:
# MonthEnd
roll_func = cbday.rollback
return roll_func
@cache_readonly
def m_offset(self):
if self._prefix.endswith("S"):
# MonthBegin
moff = MonthBegin(n=1, normalize=False)
else:
# MonthEnd
moff = MonthEnd(n=1, normalize=False)
return moff
@cache_readonly
def month_roll(self):
"""
Define default roll function to be called in apply method.
"""
if self._prefix.endswith("S"):
# MonthBegin
roll_func = self.m_offset.rollback
else:
# MonthEnd
roll_func = self.m_offset.rollforward
return roll_func
@apply_wraps
def apply(self, other):
# First move to month offset
cur_month_offset_date = self.month_roll(other)
# Find this custom month offset
compare_date = self.cbday_roll(cur_month_offset_date)
n = liboffsets.roll_convention(other.day, self.n, compare_date.day)
new = cur_month_offset_date + n * self.m_offset
result = self.cbday_roll(new)
return result
@Substitution(bound="end")
@Appender(_CustomBusinessMonth.__doc__)
class CustomBusinessMonthEnd(_CustomBusinessMonth):
_prefix = "CBM"
@Substitution(bound="beginning")
@Appender(_CustomBusinessMonth.__doc__)
class CustomBusinessMonthBegin(_CustomBusinessMonth):
_prefix = "CBMS"
# ---------------------------------------------------------------------
# Semi-Month Based Offset Classes
class SemiMonthOffset(DateOffset):
_adjust_dst = True
_default_day_of_month = 15
_min_day_of_month = 2
_attributes = frozenset(["n", "normalize", "day_of_month"])
def __init__(self, n=1, normalize=False, day_of_month=None):
BaseOffset.__init__(self, n, normalize)
if day_of_month is None:
object.__setattr__(self, "day_of_month", self._default_day_of_month)
else:
object.__setattr__(self, "day_of_month", int(day_of_month))
if not self._min_day_of_month <= self.day_of_month <= 27:
raise ValueError(
"day_of_month must be "
f"{self._min_day_of_month}<=day_of_month<=27, "
f"got {self.day_of_month}"
)
@classmethod
def _from_name(cls, suffix=None):
return cls(day_of_month=suffix)
@property
def rule_code(self):
suffix = f"-{self.day_of_month}"
return self._prefix + suffix
@apply_wraps
def apply(self, other):
# shift `other` to self.day_of_month, incrementing `n` if necessary
n = liboffsets.roll_convention(other.day, self.n, self.day_of_month)
days_in_month = ccalendar.get_days_in_month(other.year, other.month)
# For SemiMonthBegin on other.day == 1 and
# SemiMonthEnd on other.day == days_in_month,
# shifting `other` to `self.day_of_month` _always_ requires
# incrementing/decrementing `n`, regardless of whether it is
# initially positive.
if type(self) is SemiMonthBegin and (self.n <= 0 and other.day == 1):
n -= 1
elif type(self) is SemiMonthEnd and (self.n > 0 and other.day == days_in_month):
n += 1
return self._apply(n, other)
def _apply(self, n, other):
"""
Handle specific apply logic for child classes.
"""
raise AbstractMethodError(self)
@apply_index_wraps
def apply_index(self, i):
# determine how many days away from the 1st of the month we are
dti = i
days_from_start = i.to_perioddelta("M").asi8
delta = Timedelta(days=self.day_of_month - 1).value
# get boolean array for each element before the day_of_month
before_day_of_month = days_from_start < delta
# get boolean array for each element after the day_of_month
after_day_of_month = days_from_start > delta
# determine the correct n for each date in i
roll = self._get_roll(i, before_day_of_month, after_day_of_month)
# isolate the time since it will be striped away one the next line
time = i.to_perioddelta("D")
# apply the correct number of months
# integer-array addition on PeriodIndex is deprecated,
# so we use _addsub_int_array directly
asper = i.to_period("M")
if not isinstance(asper._data, np.ndarray):
# unwrap PeriodIndex --> PeriodArray
asper = asper._data
shifted = asper._addsub_int_array(roll // 2, operator.add)
i = type(dti)(shifted.to_timestamp())
# apply the correct day
i = self._apply_index_days(i, roll)
return i + time
def _get_roll(self, i, before_day_of_month, after_day_of_month):
"""
Return an array with the correct n for each date in i.
The roll array is based on the fact that i gets rolled back to
the first day of the month.
"""
raise AbstractMethodError(self)
def _apply_index_days(self, i, roll):
"""
Apply the correct day for each date in i.
"""
raise AbstractMethodError(self)
class SemiMonthEnd(SemiMonthOffset):
"""
Two DateOffset's per month repeating on the last
day of the month and day_of_month.
Parameters
----------
n : int
normalize : bool, default False
day_of_month : int, {1, 3,...,27}, default 15
"""
_prefix = "SM"
_min_day_of_month = 1
def is_on_offset(self, dt):
if self.normalize and not _is_normalized(dt):
return False
days_in_month = ccalendar.get_days_in_month(dt.year, dt.month)
return dt.day in (self.day_of_month, days_in_month)
def _apply(self, n, other):
months = n // 2
day = 31 if n % 2 else self.day_of_month
return shift_month(other, months, day)
def _get_roll(self, i, before_day_of_month, after_day_of_month):
n = self.n
is_month_end = i.is_month_end
if n > 0:
roll_end = np.where(is_month_end, 1, 0)
roll_before = np.where(before_day_of_month, n, n + 1)
roll = roll_end + roll_before
elif n == 0:
roll_after = np.where(after_day_of_month, 2, 0)
roll_before = np.where(~after_day_of_month, 1, 0)
roll = roll_before + roll_after
else:
roll = np.where(after_day_of_month, n + 2, n + 1)
return roll
def _apply_index_days(self, i, roll):
"""
Add days portion of offset to DatetimeIndex i.
Parameters
----------
i : DatetimeIndex
roll : ndarray[int64_t]
Returns
-------
result : DatetimeIndex
"""
nanos = (roll % 2) * Timedelta(days=self.day_of_month).value
i += nanos.astype("timedelta64[ns]")
return i + Timedelta(days=-1)
class SemiMonthBegin(SemiMonthOffset):
"""
Two DateOffset's per month repeating on the first
day of the month and day_of_month.
Parameters
----------
n : int
normalize : bool, default False
day_of_month : int, {2, 3,...,27}, default 15
"""
_prefix = "SMS"
def is_on_offset(self, dt):
if self.normalize and not _is_normalized(dt):
return False
return dt.day in (1, self.day_of_month)
def _apply(self, n, other):
months = n // 2 + n % 2
day = 1 if n % 2 else self.day_of_month
return shift_month(other, months, day)
def _get_roll(self, i, before_day_of_month, after_day_of_month):
n = self.n
is_month_start = i.is_month_start
if n > 0:
roll = np.where(before_day_of_month, n, n + 1)
elif n == 0:
roll_start = np.where(is_month_start, 0, 1)
roll_after = np.where(after_day_of_month, 1, 0)
roll = roll_start + roll_after
else:
roll_after = np.where(after_day_of_month, n + 2, n + 1)
roll_start = np.where(is_month_start, -1, 0)
roll = roll_after + roll_start
return roll
def _apply_index_days(self, i, roll):
"""
Add days portion of offset to DatetimeIndex i.
Parameters
----------
i : DatetimeIndex
roll : ndarray[int64_t]
Returns
-------
result : DatetimeIndex
"""
nanos = (roll % 2) * Timedelta(days=self.day_of_month - 1).value
return i + nanos.astype("timedelta64[ns]")
# ---------------------------------------------------------------------
# Week-Based Offset Classes
class Week(DateOffset):
"""
Weekly offset.
Parameters
----------
weekday : int, default None
Always generate specific day of week. 0 for Monday.
"""
_adjust_dst = True
_inc = timedelta(weeks=1)
_prefix = "W"
_attributes = frozenset(["n", "normalize", "weekday"])
def __init__(self, n=1, normalize=False, weekday=None):
BaseOffset.__init__(self, n, normalize)
object.__setattr__(self, "weekday", weekday)
if self.weekday is not None:
if self.weekday < 0 or self.weekday > 6:
raise ValueError(f"Day must be 0<=day<=6, got {self.weekday}")
def is_anchored(self):
return self.n == 1 and self.weekday is not None
@apply_wraps
def apply(self, other):
if self.weekday is None:
return other + self.n * self._inc
if not isinstance(other, datetime):
raise TypeError(
f"Cannot add {type(other).__name__} to {type(self).__name__}"
)
k = self.n
otherDay = other.weekday()
if otherDay != self.weekday:
other = other + timedelta((self.weekday - otherDay) % 7)
if k > 0:
k -= 1
return other + timedelta(weeks=k)
@apply_index_wraps
def apply_index(self, i):
if self.weekday is None:
# integer addition on PeriodIndex is deprecated,
# so we use _time_shift directly
asper = i.to_period("W")
if not isinstance(asper._data, np.ndarray):
# unwrap PeriodIndex --> PeriodArray
asper = asper._data
shifted = asper._time_shift(self.n)
return shifted.to_timestamp() + i.to_perioddelta("W")
else:
return self._end_apply_index(i)
def _end_apply_index(self, dtindex):
"""
Add self to the given DatetimeIndex, specialized for case where
self.weekday is non-null.
Parameters
----------
dtindex : DatetimeIndex
Returns
-------
result : DatetimeIndex
"""
off = dtindex.to_perioddelta("D")
base, mult = libfrequencies.get_freq_code(self.freqstr)
base_period = dtindex.to_period(base)
if not isinstance(base_period._data, np.ndarray):
# unwrap PeriodIndex --> PeriodArray
base_period = base_period._data
if self.n > 0:
# when adding, dates on end roll to next
normed = dtindex - off + Timedelta(1, "D") - Timedelta(1, "ns")
roll = np.where(
base_period.to_timestamp(how="end") == normed, self.n, self.n - 1
)
# integer-array addition on PeriodIndex is deprecated,
# so we use _addsub_int_array directly
shifted = base_period._addsub_int_array(roll, operator.add)
base = shifted.to_timestamp(how="end")
else:
# integer addition on PeriodIndex is deprecated,
# so we use _time_shift directly
roll = self.n
base = base_period._time_shift(roll).to_timestamp(how="end")
return base + off + Timedelta(1, "ns") - Timedelta(1, "D")
def is_on_offset(self, dt):
if self.normalize and not _is_normalized(dt):
return False
elif self.weekday is None:
return True
return dt.weekday() == self.weekday
@property
def rule_code(self):
suffix = ""
if self.weekday is not None:
weekday = ccalendar.int_to_weekday[self.weekday]
suffix = f"-{weekday}"
return self._prefix + suffix
@classmethod
def _from_name(cls, suffix=None):
if not suffix:
weekday = None
else:
weekday = ccalendar.weekday_to_int[suffix]
return cls(weekday=weekday)
class _WeekOfMonthMixin:
"""
Mixin for methods common to WeekOfMonth and LastWeekOfMonth.
"""
@apply_wraps
def apply(self, other):
compare_day = self._get_offset_day(other)
months = self.n
if months > 0 and compare_day > other.day:
months -= 1
elif months <= 0 and compare_day < other.day:
months += 1
shifted = shift_month(other, months, "start")
to_day = self._get_offset_day(shifted)
return liboffsets.shift_day(shifted, to_day - shifted.day)
def is_on_offset(self, dt):
if self.normalize and not _is_normalized(dt):
return False
return dt.day == self._get_offset_day(dt)
class WeekOfMonth(_WeekOfMonthMixin, DateOffset):
"""
Describes monthly dates like "the Tuesday of the 2nd week of each month".
Parameters
----------
n : int
week : int {0, 1, 2, 3, ...}, default 0
A specific integer for the week of the month.
e.g. 0 is 1st week of month, 1 is the 2nd week, etc.
weekday : int {0, 1, ..., 6}, default 0
A specific integer for the day of the week.
- 0 is Monday
- 1 is Tuesday
- 2 is Wednesday
- 3 is Thursday
- 4 is Friday
- 5 is Saturday
- 6 is Sunday.
"""
_prefix = "WOM"
_adjust_dst = True
_attributes = frozenset(["n", "normalize", "week", "weekday"])
def __init__(self, n=1, normalize=False, week=0, weekday=0):
BaseOffset.__init__(self, n, normalize)
object.__setattr__(self, "weekday", weekday)
object.__setattr__(self, "week", week)
if self.weekday < 0 or self.weekday > 6:
raise ValueError(f"Day must be 0<=day<=6, got {self.weekday}")
if self.week < 0 or self.week > 3:
raise ValueError(f"Week must be 0<=week<=3, got {self.week}")
def _get_offset_day(self, other):
"""
Find the day in the same month as other that has the same
weekday as self.weekday and is the self.week'th such day in the month.
Parameters
----------
other : datetime
Returns
-------
day : int
"""
mstart = datetime(other.year, other.month, 1)
wday = mstart.weekday()
shift_days = (self.weekday - wday) % 7
return 1 + shift_days + self.week * 7
@property
def rule_code(self):
weekday = ccalendar.int_to_weekday.get(self.weekday, "")
return f"{self._prefix}-{self.week + 1}{weekday}"
@classmethod
def _from_name(cls, suffix=None):
if not suffix:
raise ValueError(f"Prefix {repr(cls._prefix)} requires a suffix.")
# TODO: handle n here...
# only one digit weeks (1 --> week 0, 2 --> week 1, etc.)
week = int(suffix[0]) - 1
weekday = ccalendar.weekday_to_int[suffix[1:]]
return cls(week=week, weekday=weekday)
class LastWeekOfMonth(_WeekOfMonthMixin, DateOffset):
"""
Describes monthly dates in last week of month like "the last Tuesday of
each month".
Parameters
----------
n : int, default 1
weekday : int {0, 1, ..., 6}, default 0
A specific integer for the day of the week.
- 0 is Monday
- 1 is Tuesday
- 2 is Wednesday
- 3 is Thursday
- 4 is Friday
- 5 is Saturday
- 6 is Sunday.
"""
_prefix = "LWOM"
_adjust_dst = True
_attributes = frozenset(["n", "normalize", "weekday"])
def __init__(self, n=1, normalize=False, weekday=0):
BaseOffset.__init__(self, n, normalize)
object.__setattr__(self, "weekday", weekday)
if self.n == 0:
raise ValueError("N cannot be 0")
if self.weekday < 0 or self.weekday > 6:
raise ValueError(f"Day must be 0<=day<=6, got {self.weekday}")
def _get_offset_day(self, other):
"""
Find the day in the same month as other that has the same
weekday as self.weekday and is the last such day in the month.
Parameters
----------
other: datetime
Returns
-------
day: int
"""
dim = ccalendar.get_days_in_month(other.year, other.month)
mend = datetime(other.year, other.month, dim)
wday = mend.weekday()
shift_days = (wday - self.weekday) % 7
return dim - shift_days
@property
def rule_code(self):
weekday = ccalendar.int_to_weekday.get(self.weekday, "")
return f"{self._prefix}-{weekday}"
@classmethod
def _from_name(cls, suffix=None):
if not suffix:
raise ValueError(f"Prefix {repr(cls._prefix)} requires a suffix.")
# TODO: handle n here...
weekday = ccalendar.weekday_to_int[suffix]
return cls(weekday=weekday)
# ---------------------------------------------------------------------
# Quarter-Based Offset Classes
class QuarterOffset(DateOffset):
"""
Quarter representation - doesn't call super.
"""
_default_startingMonth: Optional[int] = None
_from_name_startingMonth: Optional[int] = None
_adjust_dst = True
_attributes = frozenset(["n", "normalize", "startingMonth"])
# TODO: Consider combining QuarterOffset and YearOffset __init__ at some
# point. Also apply_index, is_on_offset, rule_code if
# startingMonth vs month attr names are resolved
def __init__(self, n=1, normalize=False, startingMonth=None):
BaseOffset.__init__(self, n, normalize)
if startingMonth is None:
startingMonth = self._default_startingMonth
object.__setattr__(self, "startingMonth", startingMonth)
def is_anchored(self):
return self.n == 1 and self.startingMonth is not None
@classmethod
def _from_name(cls, suffix=None):
kwargs = {}
if suffix:
kwargs["startingMonth"] = ccalendar.MONTH_TO_CAL_NUM[suffix]
else:
if cls._from_name_startingMonth is not None:
kwargs["startingMonth"] = cls._from_name_startingMonth
return cls(**kwargs)
@property
def rule_code(self):
month = ccalendar.MONTH_ALIASES[self.startingMonth]
return f"{self._prefix}-{month}"
@apply_wraps
def apply(self, other):
# months_since: find the calendar quarter containing other.month,
# e.g. if other.month == 8, the calendar quarter is [Jul, Aug, Sep].
# Then find the month in that quarter containing an is_on_offset date for
# self. `months_since` is the number of months to shift other.month
# to get to this on-offset month.
months_since = other.month % 3 - self.startingMonth % 3
qtrs = liboffsets.roll_qtrday(
other, self.n, self.startingMonth, day_opt=self._day_opt, modby=3
)
months = qtrs * 3 - months_since
return shift_month(other, months, self._day_opt)
def is_on_offset(self, dt):
if self.normalize and not _is_normalized(dt):
return False
mod_month = (dt.month - self.startingMonth) % 3
return mod_month == 0 and dt.day == self._get_offset_day(dt)
@apply_index_wraps
def apply_index(self, dtindex):
shifted = liboffsets.shift_quarters(
dtindex.asi8, self.n, self.startingMonth, self._day_opt
)
# TODO: going through __new__ raises on call to _validate_frequency;
# are we passing incorrect freq?
return type(dtindex)._simple_new(
shifted, freq=dtindex.freq, dtype=dtindex.dtype
)
class BQuarterEnd(QuarterOffset):
"""
DateOffset increments between business Quarter dates.
startingMonth = 1 corresponds to dates like 1/31/2007, 4/30/2007, ...
startingMonth = 2 corresponds to dates like 2/28/2007, 5/31/2007, ...
startingMonth = 3 corresponds to dates like 3/30/2007, 6/29/2007, ...
"""
_outputName = "BusinessQuarterEnd"
_default_startingMonth = 3
_from_name_startingMonth = 12
_prefix = "BQ"
_day_opt = "business_end"
# TODO: This is basically the same as BQuarterEnd
class BQuarterBegin(QuarterOffset):
_outputName = "BusinessQuarterBegin"
# I suspect this is wrong for *all* of them.
_default_startingMonth = 3
_from_name_startingMonth = 1
_prefix = "BQS"
_day_opt = "business_start"
class QuarterEnd(QuarterOffset):
"""
DateOffset increments between business Quarter dates.
startingMonth = 1 corresponds to dates like 1/31/2007, 4/30/2007, ...
startingMonth = 2 corresponds to dates like 2/28/2007, 5/31/2007, ...
startingMonth = 3 corresponds to dates like 3/31/2007, 6/30/2007, ...
"""
_outputName = "QuarterEnd"
_default_startingMonth = 3
_prefix = "Q"
_day_opt = "end"
class QuarterBegin(QuarterOffset):
_outputName = "QuarterBegin"
_default_startingMonth = 3
_from_name_startingMonth = 1
_prefix = "QS"
_day_opt = "start"
# ---------------------------------------------------------------------
# Year-Based Offset Classes
class YearOffset(DateOffset):
"""
DateOffset that just needs a month.
"""
_adjust_dst = True
_attributes = frozenset(["n", "normalize", "month"])
def _get_offset_day(self, other):
# override BaseOffset method to use self.month instead of other.month
# TODO: there may be a more performant way to do this
return liboffsets.get_day_of_month(
other.replace(month=self.month), self._day_opt
)
@apply_wraps
def apply(self, other):
years = roll_yearday(other, self.n, self.month, self._day_opt)
months = years * 12 + (self.month - other.month)
return shift_month(other, months, self._day_opt)
@apply_index_wraps
def apply_index(self, dtindex):
shifted = liboffsets.shift_quarters(
dtindex.asi8, self.n, self.month, self._day_opt, modby=12
)
# TODO: going through __new__ raises on call to _validate_frequency;
# are we passing incorrect freq?
return type(dtindex)._simple_new(
shifted, freq=dtindex.freq, dtype=dtindex.dtype
)
def is_on_offset(self, dt):
if self.normalize and not _is_normalized(dt):
return False
return dt.month == self.month and dt.day == self._get_offset_day(dt)
def __init__(self, n=1, normalize=False, month=None):
BaseOffset.__init__(self, n, normalize)
month = month if month is not None else self._default_month
object.__setattr__(self, "month", month)
if self.month < 1 or self.month > 12:
raise ValueError("Month must go from 1 to 12")
@classmethod
def _from_name(cls, suffix=None):
kwargs = {}
if suffix:
kwargs["month"] = ccalendar.MONTH_TO_CAL_NUM[suffix]
return cls(**kwargs)
@property
def rule_code(self):
month = ccalendar.MONTH_ALIASES[self.month]
return f"{self._prefix}-{month}"
class BYearEnd(YearOffset):
"""
DateOffset increments between business EOM dates.
"""
_outputName = "BusinessYearEnd"
_default_month = 12
_prefix = "BA"
_day_opt = "business_end"
class BYearBegin(YearOffset):
"""
DateOffset increments between business year begin dates.
"""
_outputName = "BusinessYearBegin"
_default_month = 1
_prefix = "BAS"
_day_opt = "business_start"
class YearEnd(YearOffset):
"""
DateOffset increments between calendar year ends.
"""
_default_month = 12
_prefix = "A"
_day_opt = "end"
class YearBegin(YearOffset):
"""
DateOffset increments between calendar year begin dates.
"""
_default_month = 1
_prefix = "AS"
_day_opt = "start"
# ---------------------------------------------------------------------
# Special Offset Classes
class FY5253(DateOffset):
"""
Describes 52-53 week fiscal year. This is also known as a 4-4-5 calendar.
It is used by companies that desire that their
fiscal year always end on the same day of the week.
It is a method of managing accounting periods.
It is a common calendar structure for some industries,
such as retail, manufacturing and parking industry.
For more information see:
http://en.wikipedia.org/wiki/4-4-5_calendar
The year may either:
- end on the last X day of the Y month.
- end on the last X day closest to the last day of the Y month.
X is a specific day of the week.
Y is a certain month of the year
Parameters
----------
n : int
weekday : int {0, 1, ..., 6}, default 0
A specific integer for the day of the week.
- 0 is Monday
- 1 is Tuesday
- 2 is Wednesday
- 3 is Thursday
- 4 is Friday
- 5 is Saturday
- 6 is Sunday.
startingMonth : int {1, 2, ... 12}, default 1
The month in which the fiscal year ends.
variation : str, default "nearest"
Method of employing 4-4-5 calendar.
There are two options:
- "nearest" means year end is **weekday** closest to last day of month in year.
- "last" means year end is final **weekday** of the final month in fiscal year.
"""
_prefix = "RE"
_adjust_dst = True
_attributes = frozenset(["weekday", "startingMonth", "variation"])
def __init__(
self, n=1, normalize=False, weekday=0, startingMonth=1, variation="nearest"
):
BaseOffset.__init__(self, n, normalize)
object.__setattr__(self, "startingMonth", startingMonth)
object.__setattr__(self, "weekday", weekday)
object.__setattr__(self, "variation", variation)
if self.n == 0:
raise ValueError("N cannot be 0")
if self.variation not in ["nearest", "last"]:
raise ValueError(f"{self.variation} is not a valid variation")
def is_anchored(self):
return (
self.n == 1 and self.startingMonth is not None and self.weekday is not None
)
def is_on_offset(self, dt):
if self.normalize and not _is_normalized(dt):
return False
dt = datetime(dt.year, dt.month, dt.day)
year_end = self.get_year_end(dt)
if self.variation == "nearest":
# We have to check the year end of "this" cal year AND the previous
return year_end == dt or self.get_year_end(shift_month(dt, -1, None)) == dt
else:
return year_end == dt
@apply_wraps
def apply(self, other):
norm = Timestamp(other).normalize()
n = self.n
prev_year = self.get_year_end(datetime(other.year - 1, self.startingMonth, 1))
cur_year = self.get_year_end(datetime(other.year, self.startingMonth, 1))
next_year = self.get_year_end(datetime(other.year + 1, self.startingMonth, 1))
prev_year = conversion.localize_pydatetime(prev_year, other.tzinfo)
cur_year = conversion.localize_pydatetime(cur_year, other.tzinfo)
next_year = conversion.localize_pydatetime(next_year, other.tzinfo)
# Note: next_year.year == other.year + 1, so we will always
# have other < next_year
if norm == prev_year:
n -= 1
elif norm == cur_year:
pass
elif n > 0:
if norm < prev_year:
n -= 2
elif prev_year < norm < cur_year:
n -= 1
elif cur_year < norm < next_year:
pass
else:
if cur_year < norm < next_year:
n += 1
elif prev_year < norm < cur_year:
pass
elif (
norm.year == prev_year.year
and norm < prev_year
and prev_year - norm <= timedelta(6)
):
# GH#14774, error when next_year.year == cur_year.year
# e.g. prev_year == datetime(2004, 1, 3),
# other == datetime(2004, 1, 1)
n -= 1
else:
assert False
shifted = datetime(other.year + n, self.startingMonth, 1)
result = self.get_year_end(shifted)
result = datetime(
result.year,
result.month,
result.day,
other.hour,
other.minute,
other.second,
other.microsecond,
)
return result
def get_year_end(self, dt):
assert dt.tzinfo is None
dim = ccalendar.get_days_in_month(dt.year, self.startingMonth)
target_date = datetime(dt.year, self.startingMonth, dim)
wkday_diff = self.weekday - target_date.weekday()
if wkday_diff == 0:
# year_end is the same for "last" and "nearest" cases
return target_date
if self.variation == "last":
days_forward = (wkday_diff % 7) - 7
# days_forward is always negative, so we always end up
# in the same year as dt
return target_date + timedelta(days=days_forward)
else:
# variation == "nearest":
days_forward = wkday_diff % 7
if days_forward <= 3:
# The upcoming self.weekday is closer than the previous one
return target_date + timedelta(days_forward)
else:
# The previous self.weekday is closer than the upcoming one
return target_date + timedelta(days_forward - 7)
@property
def rule_code(self):
prefix = self._prefix
suffix = self.get_rule_code_suffix()
return f"{prefix}-{suffix}"
def _get_suffix_prefix(self):
if self.variation == "nearest":
return "N"
else:
return "L"
def get_rule_code_suffix(self):
prefix = self._get_suffix_prefix()
month = ccalendar.MONTH_ALIASES[self.startingMonth]
weekday = ccalendar.int_to_weekday[self.weekday]
return f"{prefix}-{month}-{weekday}"
@classmethod
def _parse_suffix(cls, varion_code, startingMonth_code, weekday_code):
if varion_code == "N":
variation = "nearest"
elif varion_code == "L":
variation = "last"
else:
raise ValueError(f"Unable to parse varion_code: {varion_code}")
startingMonth = ccalendar.MONTH_TO_CAL_NUM[startingMonth_code]
weekday = ccalendar.weekday_to_int[weekday_code]
return {
"weekday": weekday,
"startingMonth": startingMonth,
"variation": variation,
}
@classmethod
def _from_name(cls, *args):
return cls(**cls._parse_suffix(*args))
class FY5253Quarter(DateOffset):
"""
DateOffset increments between business quarter dates
for 52-53 week fiscal year (also known as a 4-4-5 calendar).
It is used by companies that desire that their
fiscal year always end on the same day of the week.
It is a method of managing accounting periods.
It is a common calendar structure for some industries,
such as retail, manufacturing and parking industry.
For more information see:
http://en.wikipedia.org/wiki/4-4-5_calendar
The year may either:
- end on the last X day of the Y month.
- end on the last X day closest to the last day of the Y month.
X is a specific day of the week.
Y is a certain month of the year
startingMonth = 1 corresponds to dates like 1/31/2007, 4/30/2007, ...
startingMonth = 2 corresponds to dates like 2/28/2007, 5/31/2007, ...
startingMonth = 3 corresponds to dates like 3/30/2007, 6/29/2007, ...
Parameters
----------
n : int
weekday : int {0, 1, ..., 6}, default 0
A specific integer for the day of the week.
- 0 is Monday
- 1 is Tuesday
- 2 is Wednesday
- 3 is Thursday
- 4 is Friday
- 5 is Saturday
- 6 is Sunday.
startingMonth : int {1, 2, ..., 12}, default 1
The month in which fiscal years end.
qtr_with_extra_week : int {1, 2, 3, 4}, default 1
The quarter number that has the leap or 14 week when needed.
variation : str, default "nearest"
Method of employing 4-4-5 calendar.
There are two options:
- "nearest" means year end is **weekday** closest to last day of month in year.
- "last" means year end is final **weekday** of the final month in fiscal year.
"""
_prefix = "REQ"
_adjust_dst = True
_attributes = frozenset(
["weekday", "startingMonth", "qtr_with_extra_week", "variation"]
)
def __init__(
self,
n=1,
normalize=False,
weekday=0,
startingMonth=1,
qtr_with_extra_week=1,
variation="nearest",
):
BaseOffset.__init__(self, n, normalize)
object.__setattr__(self, "startingMonth", startingMonth)
object.__setattr__(self, "weekday", weekday)
object.__setattr__(self, "qtr_with_extra_week", qtr_with_extra_week)
object.__setattr__(self, "variation", variation)
if self.n == 0:
raise ValueError("N cannot be 0")
@cache_readonly
def _offset(self):
return FY5253(
startingMonth=self.startingMonth,
weekday=self.weekday,
variation=self.variation,
)
def is_anchored(self):
return self.n == 1 and self._offset.is_anchored()
def _rollback_to_year(self, other):
"""
Roll `other` back to the most recent date that was on a fiscal year
end.
Return the date of that year-end, the number of full quarters
elapsed between that year-end and other, and the remaining Timedelta
since the most recent quarter-end.
Parameters
----------
other : datetime or Timestamp
Returns
-------
tuple of
prev_year_end : Timestamp giving most recent fiscal year end
num_qtrs : int
tdelta : Timedelta
"""
num_qtrs = 0
norm = Timestamp(other).tz_localize(None)
start = self._offset.rollback(norm)
# Note: start <= norm and self._offset.is_on_offset(start)
if start < norm:
# roll adjustment
qtr_lens = self.get_weeks(norm)
# check thet qtr_lens is consistent with self._offset addition
end = liboffsets.shift_day(start, days=7 * sum(qtr_lens))
assert self._offset.is_on_offset(end), (start, end, qtr_lens)
tdelta = norm - start
for qlen in qtr_lens:
if qlen * 7 <= tdelta.days:
num_qtrs += 1
tdelta -= Timedelta(days=qlen * 7)
else:
break
else:
tdelta = Timedelta(0)
# Note: we always have tdelta.value >= 0
return start, num_qtrs, tdelta
@apply_wraps
def apply(self, other):
# Note: self.n == 0 is not allowed.
n = self.n
prev_year_end, num_qtrs, tdelta = self._rollback_to_year(other)
res = prev_year_end
n += num_qtrs
if self.n <= 0 and tdelta.value > 0:
n += 1
# Possible speedup by handling years first.
years = n // 4
if years:
res += self._offset * years
n -= years * 4
# Add an extra day to make *sure* we are getting the quarter lengths
# for the upcoming year, not the previous year
qtr_lens = self.get_weeks(res + Timedelta(days=1))
# Note: we always have 0 <= n < 4
weeks = sum(qtr_lens[:n])
if weeks:
res = liboffsets.shift_day(res, days=weeks * 7)
return res
def get_weeks(self, dt):
ret = [13] * 4
year_has_extra_week = self.year_has_extra_week(dt)
if year_has_extra_week:
ret[self.qtr_with_extra_week - 1] = 14
return ret
def year_has_extra_week(self, dt):
# Avoid round-down errors --> normalize to get
# e.g. '370D' instead of '360D23H'
norm = Timestamp(dt).normalize().tz_localize(None)
next_year_end = self._offset.rollforward(norm)
prev_year_end = norm - self._offset
weeks_in_year = (next_year_end - prev_year_end).days / 7
assert weeks_in_year in [52, 53], weeks_in_year
return weeks_in_year == 53
def is_on_offset(self, dt):
if self.normalize and not _is_normalized(dt):
return False
if self._offset.is_on_offset(dt):
return True
next_year_end = dt - self._offset
qtr_lens = self.get_weeks(dt)
current = next_year_end
for qtr_len in qtr_lens:
current = liboffsets.shift_day(current, days=qtr_len * 7)
if dt == current:
return True
return False
@property
def rule_code(self):
suffix = self._offset.get_rule_code_suffix()
qtr = self.qtr_with_extra_week
return f"{self._prefix}-{suffix}-{qtr}"
@classmethod
def _from_name(cls, *args):
return cls(
**dict(FY5253._parse_suffix(*args[:-1]), qtr_with_extra_week=int(args[-1]))
)
class Easter(DateOffset):
"""
DateOffset for the Easter holiday using logic defined in dateutil.
Right now uses the revised method which is valid in years 1583-4099.
"""
_adjust_dst = True
_attributes = frozenset(["n", "normalize"])
__init__ = BaseOffset.__init__
@apply_wraps
def apply(self, other):
current_easter = easter(other.year)
current_easter = datetime(
current_easter.year, current_easter.month, current_easter.day
)
current_easter = conversion.localize_pydatetime(current_easter, other.tzinfo)
n = self.n
if n >= 0 and other < current_easter:
n -= 1
elif n < 0 and other > current_easter:
n += 1
# TODO: Why does this handle the 0 case the opposite of others?
# NOTE: easter returns a datetime.date so we have to convert to type of
# other
new = easter(other.year + n)
new = datetime(
new.year,
new.month,
new.day,
other.hour,
other.minute,
other.second,
other.microsecond,
)
return new
def is_on_offset(self, dt):
if self.normalize and not _is_normalized(dt):
return False
return date(dt.year, dt.month, dt.day) == easter(dt.year)
# ---------------------------------------------------------------------
# Ticks
def _tick_comp(op):
assert op not in [operator.eq, operator.ne]
def f(self, other):
try:
return op(self.delta, other.delta)
except AttributeError:
# comparing with a non-Tick object
raise TypeError(
f"Invalid comparison between {type(self).__name__} "
f"and {type(other).__name__}"
)
f.__name__ = f"__{op.__name__}__"
return f
class Tick(liboffsets._Tick, SingleConstructorOffset):
_inc = Timedelta(microseconds=1000)
_prefix = "undefined"
_attributes = frozenset(["n", "normalize"])
def __init__(self, n=1, normalize=False):
BaseOffset.__init__(self, n, normalize)
if normalize:
raise ValueError(
"Tick offset with `normalize=True` are not allowed."
) # GH#21427
__gt__ = _tick_comp(operator.gt)
__ge__ = _tick_comp(operator.ge)
__lt__ = _tick_comp(operator.lt)
__le__ = _tick_comp(operator.le)
def __add__(self, other):
if isinstance(other, Tick):
if type(self) == type(other):
return type(self)(self.n + other.n)
else:
return _delta_to_tick(self.delta + other.delta)
elif isinstance(other, Period):
return other + self
try:
return self.apply(other)
except ApplyTypeError:
return NotImplemented
except OverflowError:
raise OverflowError(
f"the add operation between {self} and {other} will overflow"
)
def __eq__(self, other: Any) -> bool:
if isinstance(other, str):
from pandas.tseries.frequencies import to_offset
try:
# GH#23524 if to_offset fails, we are dealing with an
# incomparable type so == is False and != is True
other = to_offset(other)
except ValueError:
# e.g. "infer"
return False
if isinstance(other, Tick):
return self.delta == other.delta
else:
return False
# This is identical to DateOffset.__hash__, but has to be redefined here
# for Python 3, because we've redefined __eq__.
def __hash__(self):
return hash(self._params)
def __ne__(self, other):
if isinstance(other, str):
from pandas.tseries.frequencies import to_offset
try:
# GH#23524 if to_offset fails, we are dealing with an
# incomparable type so == is False and != is True
other = to_offset(other)
except ValueError:
# e.g. "infer"
return True
if isinstance(other, Tick):
return self.delta != other.delta
else:
return True
@property
def delta(self):
return self.n * self._inc
@property
def nanos(self):
return delta_to_nanoseconds(self.delta)
# TODO: Should Tick have its own apply_index?
def apply(self, other):
# Timestamp can handle tz and nano sec, thus no need to use apply_wraps
if isinstance(other, Timestamp):
# GH 15126
# in order to avoid a recursive
# call of __add__ and __radd__ if there is
# an exception, when we call using the + operator,
# we directly call the known method
result = other.__add__(self)
if result is NotImplemented:
raise OverflowError
return result
elif isinstance(other, (datetime, np.datetime64, date)):
return as_timestamp(other) + self
if isinstance(other, timedelta):
return other + self.delta
elif isinstance(other, type(self)):
return type(self)(self.n + other.n)
raise ApplyTypeError(f"Unhandled type: {type(other).__name__}")
def is_anchored(self):
return False
def _delta_to_tick(delta):
if delta.microseconds == 0 and getattr(delta, "nanoseconds", 0) == 0:
# nanoseconds only for pd.Timedelta
if delta.seconds == 0:
return Day(delta.days)
else:
seconds = delta.days * 86400 + delta.seconds
if seconds % 3600 == 0:
return Hour(seconds / 3600)
elif seconds % 60 == 0:
return Minute(seconds / 60)
else:
return Second(seconds)
else:
nanos = delta_to_nanoseconds(delta)
if nanos % 1000000 == 0:
return Milli(nanos // 1000000)
elif nanos % 1000 == 0:
return Micro(nanos // 1000)
else: # pragma: no cover
return Nano(nanos)
class Day(Tick):
_inc = Timedelta(days=1)
_prefix = "D"
class Hour(Tick):
_inc = Timedelta(hours=1)
_prefix = "H"
class Minute(Tick):
_inc = Timedelta(minutes=1)
_prefix = "T"
class Second(Tick):
_inc = Timedelta(seconds=1)
_prefix = "S"
class Milli(Tick):
_inc = Timedelta(milliseconds=1)
_prefix = "L"
class Micro(Tick):
_inc = Timedelta(microseconds=1)
_prefix = "U"
class Nano(Tick):
_inc = Timedelta(nanoseconds=1)
_prefix = "N"
BDay = BusinessDay
BMonthEnd = BusinessMonthEnd
BMonthBegin = BusinessMonthBegin
CBMonthEnd = CustomBusinessMonthEnd
CBMonthBegin = CustomBusinessMonthBegin
CDay = CustomBusinessDay
# ---------------------------------------------------------------------
def generate_range(start=None, end=None, periods=None, offset=BDay()):
"""
Generates a sequence of dates corresponding to the specified time
offset. Similar to dateutil.rrule except uses pandas DateOffset
objects to represent time increments.
Parameters
----------
start : datetime, (default None)
end : datetime, (default None)
periods : int, (default None)
offset : DateOffset, (default BDay())
Notes
-----
* This method is faster for generating weekdays than dateutil.rrule
* At least two of (start, end, periods) must be specified.
* If both start and end are specified, the returned dates will
satisfy start <= date <= end.
Returns
-------
dates : generator object
"""
from pandas.tseries.frequencies import to_offset
offset = to_offset(offset)
start = Timestamp(start)
start = start if start is not NaT else None
end = Timestamp(end)
end = end if end is not NaT else None
if start and not offset.is_on_offset(start):
start = offset.rollforward(start)
elif end and not offset.is_on_offset(end):
end = offset.rollback(end)
if periods is None and end < start and offset.n >= 0:
end = None
periods = 0
if end is None:
end = start + (periods - 1) * offset
if start is None:
start = end - (periods - 1) * offset
cur = start
if offset.n >= 0:
while cur <= end:
yield cur
if cur == end:
# GH#24252 avoid overflows by not performing the addition
# in offset.apply unless we have to
break
# faster than cur + offset
next_date = offset.apply(cur)
if next_date <= cur:
raise ValueError(f"Offset {offset} did not increment date")
cur = next_date
else:
while cur >= end:
yield cur
if cur == end:
# GH#24252 avoid overflows by not performing the addition
# in offset.apply unless we have to
break
# faster than cur + offset
next_date = offset.apply(cur)
if next_date >= cur:
raise ValueError(f"Offset {offset} did not decrement date")
cur = next_date
prefix_mapping = {
offset._prefix: offset
for offset in [
YearBegin, # 'AS'
YearEnd, # 'A'
BYearBegin, # 'BAS'
BYearEnd, # 'BA'
BusinessDay, # 'B'
BusinessMonthBegin, # 'BMS'
BusinessMonthEnd, # 'BM'
BQuarterEnd, # 'BQ'
BQuarterBegin, # 'BQS'
BusinessHour, # 'BH'
CustomBusinessDay, # 'C'
CustomBusinessMonthEnd, # 'CBM'
CustomBusinessMonthBegin, # 'CBMS'
CustomBusinessHour, # 'CBH'
MonthEnd, # 'M'
MonthBegin, # 'MS'
Nano, # 'N'
SemiMonthEnd, # 'SM'
SemiMonthBegin, # 'SMS'
Week, # 'W'
Second, # 'S'
Minute, # 'T'
Micro, # 'U'
QuarterEnd, # 'Q'
QuarterBegin, # 'QS'
Milli, # 'L'
Hour, # 'H'
Day, # 'D'
WeekOfMonth, # 'WOM'
FY5253,
FY5253Quarter,
]
}
| BugsInPy/BugsInPy/temp/projects/pandas/bug-96-fixed/pandas/pandas/tseries/offsets.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-96-buggy/pandas/pandas/tseries/offsets.py |
pandas-bug-75 | from datetime import datetime, timedelta
from typing import Any
import weakref
import numpy as np
from pandas._libs import index as libindex
from pandas._libs.tslibs import NaT, frequencies as libfrequencies, resolution
from pandas._libs.tslibs.parsing import parse_time_string
from pandas._libs.tslibs.period import Period
from pandas.util._decorators import Appender, cache_readonly
from pandas.core.dtypes.common import (
ensure_platform_int,
is_bool_dtype,
is_datetime64_any_dtype,
is_dtype_equal,
is_float,
is_integer,
is_integer_dtype,
is_list_like,
is_object_dtype,
pandas_dtype,
)
from pandas.core.accessor import delegate_names
from pandas.core.arrays.period import (
PeriodArray,
period_array,
raise_on_incompatible,
validate_dtype_freq,
)
import pandas.core.common as com
import pandas.core.indexes.base as ibase
from pandas.core.indexes.base import (
_index_shared_docs,
ensure_index,
maybe_extract_name,
)
from pandas.core.indexes.datetimelike import (
DatetimeIndexOpsMixin,
DatetimelikeDelegateMixin,
)
from pandas.core.indexes.datetimes import DatetimeIndex, Index
from pandas.core.indexes.numeric import Int64Index
from pandas.core.ops import get_op_result_name
from pandas.core.tools.datetimes import DateParseError
from pandas.tseries import frequencies
from pandas.tseries.offsets import DateOffset, Tick
_index_doc_kwargs = dict(ibase._index_doc_kwargs)
_index_doc_kwargs.update(dict(target_klass="PeriodIndex or list of Periods"))
# --- Period index sketch
def _new_PeriodIndex(cls, **d):
# GH13277 for unpickling
values = d.pop("data")
if values.dtype == "int64":
freq = d.pop("freq", None)
values = PeriodArray(values, freq=freq)
return cls._simple_new(values, **d)
else:
return cls(values, **d)
class PeriodDelegateMixin(DatetimelikeDelegateMixin):
"""
Delegate from PeriodIndex to PeriodArray.
"""
_raw_methods = {"_format_native_types"}
_raw_properties = {"is_leap_year", "freq"}
_delegated_properties = PeriodArray._datetimelike_ops + list(_raw_properties)
_delegated_methods = set(PeriodArray._datetimelike_methods) | _raw_methods
@delegate_names(PeriodArray, PeriodDelegateMixin._delegated_properties, typ="property")
@delegate_names(
PeriodArray, PeriodDelegateMixin._delegated_methods, typ="method", overwrite=True
)
class PeriodIndex(DatetimeIndexOpsMixin, Int64Index, PeriodDelegateMixin):
"""
Immutable ndarray holding ordinal values indicating regular periods in time.
Index keys are boxed to Period objects which carries the metadata (eg,
frequency information).
Parameters
----------
data : array-like (1d int np.ndarray or PeriodArray), optional
Optional period-like data to construct index with.
copy : bool
Make a copy of input ndarray.
freq : str or period object, optional
One of pandas period strings or corresponding objects
year : int, array, or Series, default None
month : int, array, or Series, default None
quarter : int, array, or Series, default None
day : int, array, or Series, default None
hour : int, array, or Series, default None
minute : int, array, or Series, default None
second : int, array, or Series, default None
tz : object, default None
Timezone for converting datetime64 data to Periods.
dtype : str or PeriodDtype, default None
Attributes
----------
day
dayofweek
dayofyear
days_in_month
daysinmonth
end_time
freq
freqstr
hour
is_leap_year
minute
month
quarter
qyear
second
start_time
week
weekday
weekofyear
year
Methods
-------
asfreq
strftime
to_timestamp
See Also
--------
Index : The base pandas Index type.
Period : Represents a period of time.
DatetimeIndex : Index with datetime64 data.
TimedeltaIndex : Index of timedelta64 data.
period_range : Create a fixed-frequency PeriodIndex.
Examples
--------
>>> idx = pd.PeriodIndex(year=year_arr, quarter=q_arr)
"""
_typ = "periodindex"
_attributes = ["name", "freq"]
# define my properties & methods for delegation
_is_numeric_dtype = False
_infer_as_myclass = True
_data: PeriodArray
_engine_type = libindex.PeriodEngine
_supports_partial_string_indexing = True
# ------------------------------------------------------------------------
# Index Constructors
def __new__(
cls,
data=None,
ordinal=None,
freq=None,
tz=None,
dtype=None,
copy=False,
name=None,
**fields,
):
valid_field_set = {
"year",
"month",
"day",
"quarter",
"hour",
"minute",
"second",
}
if not set(fields).issubset(valid_field_set):
argument = list(set(fields) - valid_field_set)[0]
raise TypeError(f"__new__() got an unexpected keyword argument {argument}")
name = maybe_extract_name(name, data, cls)
if data is None and ordinal is None:
# range-based.
data, freq2 = PeriodArray._generate_range(None, None, None, freq, fields)
# PeriodArray._generate range does validation that fields is
# empty when really using the range-based constructor.
freq = freq2
data = PeriodArray(data, freq=freq)
else:
freq = validate_dtype_freq(dtype, freq)
# PeriodIndex allow PeriodIndex(period_index, freq=different)
# Let's not encourage that kind of behavior in PeriodArray.
if freq and isinstance(data, cls) and data.freq != freq:
# TODO: We can do some of these with no-copy / coercion?
# e.g. D -> 2D seems to be OK
data = data.asfreq(freq)
if data is None and ordinal is not None:
# we strangely ignore `ordinal` if data is passed.
ordinal = np.asarray(ordinal, dtype=np.int64)
data = PeriodArray(ordinal, freq)
else:
# don't pass copy here, since we copy later.
data = period_array(data=data, freq=freq)
if copy:
data = data.copy()
return cls._simple_new(data, name=name)
@classmethod
def _simple_new(cls, values, name=None, freq=None, **kwargs):
"""
Create a new PeriodIndex.
Parameters
----------
values : PeriodArray
Values that can be converted to a PeriodArray without inference
or coercion.
"""
assert isinstance(values, PeriodArray), type(values)
assert freq is None or freq == values.freq, (freq, values.freq)
result = object.__new__(cls)
result._data = values
# For groupby perf. See note in indexes/base about _index_data
result._index_data = values._data
result.name = name
result._reset_identity()
return result
# ------------------------------------------------------------------------
# Data
@property
def values(self):
return np.asarray(self)
def _shallow_copy(self, values=None, **kwargs):
# TODO: simplify, figure out type of values
if values is None:
values = self._data
if isinstance(values, type(self)):
values = values._data
if not isinstance(values, PeriodArray):
if isinstance(values, np.ndarray) and values.dtype == "i8":
values = PeriodArray(values, freq=self.freq)
else:
# GH#30713 this should never be reached
raise TypeError(type(values), getattr(values, "dtype", None))
# We don't allow changing `freq` in _shallow_copy.
validate_dtype_freq(self.dtype, kwargs.get("freq"))
attributes = self._get_attributes_dict()
attributes.update(kwargs)
if not len(values) and "dtype" not in kwargs:
attributes["dtype"] = self.dtype
return self._simple_new(values, **attributes)
def _shallow_copy_with_infer(self, values=None, **kwargs):
""" we always want to return a PeriodIndex """
return self._shallow_copy(values=values, **kwargs)
@property
def _box_func(self):
"""Maybe box an ordinal or Period"""
# TODO(DatetimeArray): Avoid double-boxing
# PeriodArray takes care of boxing already, so we need to check
# whether we're given an ordinal or a Period. It seems like some
# places outside of indexes/period.py are calling this _box_func,
# but passing data that's already boxed.
def func(x):
if isinstance(x, Period) or x is NaT:
return x
else:
return Period._from_ordinal(ordinal=x, freq=self.freq)
return func
def _maybe_convert_timedelta(self, other):
"""
Convert timedelta-like input to an integer multiple of self.freq
Parameters
----------
other : timedelta, np.timedelta64, DateOffset, int, np.ndarray
Returns
-------
converted : int, np.ndarray[int64]
Raises
------
IncompatibleFrequency : if the input cannot be written as a multiple
of self.freq. Note IncompatibleFrequency subclasses ValueError.
"""
if isinstance(other, (timedelta, np.timedelta64, Tick, np.ndarray)):
offset = frequencies.to_offset(self.freq.rule_code)
if isinstance(offset, Tick):
# _check_timedeltalike_freq_compat will raise if incompatible
delta = self._data._check_timedeltalike_freq_compat(other)
return delta
elif isinstance(other, DateOffset):
freqstr = other.rule_code
base = libfrequencies.get_base_alias(freqstr)
if base == self.freq.rule_code:
return other.n
raise raise_on_incompatible(self, other)
elif is_integer(other):
# integer is passed to .shift via
# _add_datetimelike_methods basically
# but ufunc may pass integer to _add_delta
return other
# raise when input doesn't have freq
raise raise_on_incompatible(self, None)
# ------------------------------------------------------------------------
# Rendering Methods
def _mpl_repr(self):
# how to represent ourselves to matplotlib
return self.astype(object).values
@property
def _formatter_func(self):
return self.array._formatter(boxed=False)
# ------------------------------------------------------------------------
# Indexing
@cache_readonly
def _engine(self):
# To avoid a reference cycle, pass a weakref of self to _engine_type.
period = weakref.ref(self)
return self._engine_type(period, len(self))
@Appender(_index_shared_docs["contains"])
def __contains__(self, key: Any) -> bool:
if isinstance(key, Period):
if key.freq != self.freq:
return False
else:
return key.ordinal in self._engine
else:
hash(key)
try:
self.get_loc(key)
return True
except KeyError:
return False
@cache_readonly
def _int64index(self):
return Int64Index._simple_new(self.asi8, name=self.name)
# ------------------------------------------------------------------------
# Index Methods
def __array__(self, dtype=None) -> np.ndarray:
if is_integer_dtype(dtype):
return self.asi8
else:
return self.astype(object).values
def __array_wrap__(self, result, context=None):
"""
Gets called after a ufunc. Needs additional handling as
PeriodIndex stores internal data as int dtype
Replace this to __numpy_ufunc__ in future version
"""
if isinstance(context, tuple) and len(context) > 0:
func = context[0]
if func is np.add:
pass
elif func is np.subtract:
name = self.name
left = context[1][0]
right = context[1][1]
if isinstance(left, PeriodIndex) and isinstance(right, PeriodIndex):
name = left.name if left.name == right.name else None
return Index(result, name=name)
elif isinstance(left, Period) or isinstance(right, Period):
return Index(result, name=name)
elif isinstance(func, np.ufunc):
if "M->M" not in func.types:
msg = f"ufunc '{func.__name__}' not supported for the PeriodIndex"
# This should be TypeError, but TypeError cannot be raised
# from here because numpy catches.
raise ValueError(msg)
if is_bool_dtype(result):
return result
# the result is object dtype array of Period
# cannot pass _simple_new as it is
return type(self)(result, freq=self.freq, name=self.name)
def asof_locs(self, where, mask):
"""
where : array of timestamps
mask : array of booleans where data is not NA
"""
where_idx = where
if isinstance(where_idx, DatetimeIndex):
where_idx = PeriodIndex(where_idx.values, freq=self.freq)
locs = self._ndarray_values[mask].searchsorted(
where_idx._ndarray_values, side="right"
)
locs = np.where(locs > 0, locs - 1, 0)
result = np.arange(len(self))[mask].take(locs)
first = mask.argmax()
result[
(locs == 0) & (where_idx._ndarray_values < self._ndarray_values[first])
] = -1
return result
@Appender(_index_shared_docs["astype"])
def astype(self, dtype, copy=True, how="start"):
dtype = pandas_dtype(dtype)
if is_datetime64_any_dtype(dtype):
# 'how' is index-specific, isn't part of the EA interface.
tz = getattr(dtype, "tz", None)
return self.to_timestamp(how=how).tz_localize(tz)
# TODO: should probably raise on `how` here, so we don't ignore it.
return super().astype(dtype, copy=copy)
@property
def is_full(self) -> bool:
"""
Returns True if this PeriodIndex is range-like in that all Periods
between start and end are present, in order.
"""
if len(self) == 0:
return True
if not self.is_monotonic:
raise ValueError("Index is not monotonic")
values = self.asi8
return ((values[1:] - values[:-1]) < 2).all()
@property
def inferred_type(self) -> str:
# b/c data is represented as ints make sure we can't have ambiguous
# indexing
return "period"
def get_value(self, series, key):
"""
Fast lookup of value from 1-dimensional ndarray. Only use this if you
know what you're doing
"""
if is_integer(key):
return series.iat[key]
if isinstance(key, str):
try:
loc = self._get_string_slice(key)
return series[loc]
except (TypeError, ValueError):
pass
asdt, reso = parse_time_string(key, self.freq)
grp = resolution.Resolution.get_freq_group(reso)
freqn = resolution.get_freq_group(self.freq)
# _get_string_slice will handle cases where grp < freqn
assert grp >= freqn
if grp == freqn:
key = Period(asdt, freq=self.freq)
loc = self.get_loc(key)
return series.iloc[loc]
else:
raise KeyError(key)
elif isinstance(key, Period) or key is NaT:
ordinal = key.ordinal if key is not NaT else NaT.value
loc = self._engine.get_loc(ordinal)
return series[loc]
# slice, PeriodIndex, np.ndarray, List[Period]
value = Index.get_value(self, series, key)
return com.maybe_box(self, value, series, key)
@Appender(_index_shared_docs["get_indexer"] % _index_doc_kwargs)
def get_indexer(self, target, method=None, limit=None, tolerance=None):
target = ensure_index(target)
if isinstance(target, PeriodIndex):
if target.freq != self.freq:
# No matches
no_matches = -1 * np.ones(self.shape, dtype=np.intp)
return no_matches
target = target.asi8
self_index = self._int64index
else:
self_index = self
if tolerance is not None:
tolerance = self._convert_tolerance(tolerance, target)
return Index.get_indexer(self_index, target, method, limit, tolerance)
@Appender(_index_shared_docs["get_indexer_non_unique"] % _index_doc_kwargs)
def get_indexer_non_unique(self, target):
target = ensure_index(target)
if isinstance(target, PeriodIndex):
if target.freq != self.freq:
no_matches = -1 * np.ones(self.shape, dtype=np.intp)
return no_matches, no_matches
target = target.asi8
indexer, missing = self._int64index.get_indexer_non_unique(target)
return ensure_platform_int(indexer), missing
def get_loc(self, key, method=None, tolerance=None):
"""
Get integer location for requested label.
Parameters
----------
key : Period, NaT, str, or datetime
String or datetime key must be parseable as Period.
Returns
-------
loc : int or ndarray[int64]
Raises
------
KeyError
Key is not present in the index.
TypeError
If key is listlike or otherwise not hashable.
"""
if isinstance(key, str):
try:
return self._get_string_slice(key)
except (TypeError, KeyError, ValueError, OverflowError):
pass
try:
asdt, reso = parse_time_string(key, self.freq)
key = asdt
except DateParseError:
# A string with invalid format
raise KeyError(f"Cannot interpret '{key}' as period")
elif is_integer(key):
# Period constructor will cast to string, which we dont want
raise KeyError(key)
try:
key = Period(key, freq=self.freq)
except ValueError:
# we cannot construct the Period
# as we have an invalid type
if is_list_like(key):
raise TypeError(f"'{key}' is an invalid key")
raise KeyError(key)
ordinal = key.ordinal if key is not NaT else key.value
try:
return self._engine.get_loc(ordinal)
except KeyError:
try:
if tolerance is not None:
tolerance = self._convert_tolerance(tolerance, np.asarray(key))
return self._int64index.get_loc(ordinal, method, tolerance)
except KeyError:
raise KeyError(key)
def _maybe_cast_slice_bound(self, label, side, kind):
"""
If label is a string or a datetime, cast it to Period.ordinal according
to resolution.
Parameters
----------
label : object
side : {'left', 'right'}
kind : {'loc', 'getitem'}
Returns
-------
bound : Period or object
Notes
-----
Value of `side` parameter should be validated in caller.
"""
assert kind in ["loc", "getitem"]
if isinstance(label, datetime):
return Period(label, freq=self.freq)
elif isinstance(label, str):
try:
parsed, reso = parse_time_string(label, self.freq)
bounds = self._parsed_string_to_bounds(reso, parsed)
return bounds[0 if side == "left" else 1]
except ValueError:
# string cannot be parsed as datetime-like
# TODO: we need tests for this case
raise KeyError(label)
elif is_integer(label) or is_float(label):
self._invalid_indexer("slice", label)
return label
def _parsed_string_to_bounds(self, reso: str, parsed: datetime):
if reso not in ["year", "month", "quarter", "day", "hour", "minute", "second"]:
raise KeyError(reso)
grp = resolution.Resolution.get_freq_group(reso)
iv = Period(parsed, freq=(grp, 1))
return (iv.asfreq(self.freq, how="start"), iv.asfreq(self.freq, how="end"))
def _get_string_slice(self, key: str, use_lhs: bool = True, use_rhs: bool = True):
# TODO: Check for non-True use_lhs/use_rhs
parsed, reso = parse_time_string(key, self.freq)
grp = resolution.Resolution.get_freq_group(reso)
freqn = resolution.get_freq_group(self.freq)
if not grp < freqn:
# TODO: we used to also check for
# reso in ["day", "hour", "minute", "second"]
# why is that check not needed?
raise ValueError(key)
t1, t2 = self._parsed_string_to_bounds(reso, parsed)
i8vals = self.asi8
if self.is_monotonic:
# we are out of range
if len(self) and (
(use_lhs and t1 < self[0] and t2 < self[0])
or ((use_rhs and t1 > self[-1] and t2 > self[-1]))
):
raise KeyError(key)
# TODO: does this depend on being monotonic _increasing_?
# If so, DTI will also be affected.
# a monotonic (sorted) series can be sliced
# Use asi8.searchsorted to avoid re-validating Periods
left = i8vals.searchsorted(t1.ordinal, side="left") if use_lhs else None
right = i8vals.searchsorted(t2.ordinal, side="right") if use_rhs else None
return slice(left, right)
else:
lhs_mask = (i8vals >= t1.ordinal) if use_lhs else True
rhs_mask = (i8vals <= t2.ordinal) if use_rhs else True
# try to find a the dates
return (lhs_mask & rhs_mask).nonzero()[0]
def _convert_tolerance(self, tolerance, target):
tolerance = DatetimeIndexOpsMixin._convert_tolerance(self, tolerance, target)
if target.size != tolerance.size and tolerance.size > 1:
raise ValueError("list-like tolerance size must match target index size")
return self._maybe_convert_timedelta(tolerance)
def insert(self, loc, item):
if not isinstance(item, Period) or self.freq != item.freq:
return self.astype(object).insert(loc, item)
idx = np.concatenate(
(self[:loc].asi8, np.array([item.ordinal]), self[loc:].asi8)
)
return self._shallow_copy(idx)
def join(self, other, how="left", level=None, return_indexers=False, sort=False):
"""
See Index.join
"""
self._assert_can_do_setop(other)
if not isinstance(other, PeriodIndex):
return self.astype(object).join(
other, how=how, level=level, return_indexers=return_indexers, sort=sort
)
result = Int64Index.join(
self,
other,
how=how,
level=level,
return_indexers=return_indexers,
sort=sort,
)
if return_indexers:
result, lidx, ridx = result
return self._apply_meta(result), lidx, ridx
return self._apply_meta(result)
# ------------------------------------------------------------------------
# Set Operation Methods
def _assert_can_do_setop(self, other):
super()._assert_can_do_setop(other)
# *Can't* use PeriodIndexes of different freqs
# *Can* use PeriodIndex/DatetimeIndex
if isinstance(other, PeriodIndex) and self.freq != other.freq:
raise raise_on_incompatible(self, other)
def intersection(self, other, sort=False):
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
res_name = get_op_result_name(self, other)
other = ensure_index(other)
if self.equals(other):
return self._get_reconciled_name_object(other)
if not is_dtype_equal(self.dtype, other.dtype):
# TODO: fastpath for if we have a different PeriodDtype
this = self.astype("O")
other = other.astype("O")
return this.intersection(other, sort=sort)
i8self = Int64Index._simple_new(self.asi8)
i8other = Int64Index._simple_new(other.asi8)
i8result = i8self.intersection(i8other, sort=sort)
result = self._shallow_copy(np.asarray(i8result, dtype=np.int64), name=res_name)
return result
def difference(self, other, sort=None):
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
res_name = get_op_result_name(self, other)
other = ensure_index(other)
if self.equals(other):
# pass an empty PeriodArray with the appropriate dtype
return self._shallow_copy(self._data[:0])
if is_object_dtype(other):
return self.astype(object).difference(other).astype(self.dtype)
elif not is_dtype_equal(self.dtype, other.dtype):
return self
i8self = Int64Index._simple_new(self.asi8)
i8other = Int64Index._simple_new(other.asi8)
i8result = i8self.difference(i8other, sort=sort)
result = self._shallow_copy(np.asarray(i8result, dtype=np.int64), name=res_name)
return result
def _union(self, other, sort):
if not len(other) or self.equals(other) or not len(self):
return super()._union(other, sort=sort)
# We are called by `union`, which is responsible for this validation
assert isinstance(other, type(self))
if not is_dtype_equal(self.dtype, other.dtype):
this = self.astype("O")
other = other.astype("O")
return this._union(other, sort=sort)
i8self = Int64Index._simple_new(self.asi8)
i8other = Int64Index._simple_new(other.asi8)
i8result = i8self._union(i8other, sort=sort)
res_name = get_op_result_name(self, other)
result = self._shallow_copy(np.asarray(i8result, dtype=np.int64), name=res_name)
return result
# ------------------------------------------------------------------------
def _apply_meta(self, rawarr):
if not isinstance(rawarr, PeriodIndex):
if not isinstance(rawarr, PeriodArray):
rawarr = PeriodArray(rawarr, freq=self.freq)
rawarr = PeriodIndex._simple_new(rawarr, name=self.name)
return rawarr
def memory_usage(self, deep=False):
result = super().memory_usage(deep=deep)
if hasattr(self, "_cache") and "_int64index" in self._cache:
result += self._int64index.memory_usage(deep=deep)
return result
PeriodIndex._add_numeric_methods_disabled()
PeriodIndex._add_logical_methods_disabled()
def period_range(
start=None, end=None, periods=None, freq=None, name=None
) -> PeriodIndex:
"""
Return a fixed frequency PeriodIndex.
The day (calendar) is the default frequency.
Parameters
----------
start : str or period-like, default None
Left bound for generating periods.
end : str or period-like, default None
Right bound for generating periods.
periods : int, default None
Number of periods to generate.
freq : str or DateOffset, optional
Frequency alias. By default the freq is taken from `start` or `end`
if those are Period objects. Otherwise, the default is ``"D"`` for
daily frequency.
name : str, default None
Name of the resulting PeriodIndex.
Returns
-------
PeriodIndex
Notes
-----
Of the three parameters: ``start``, ``end``, and ``periods``, exactly two
must be specified.
To learn more about the frequency strings, please see `this link
<https://pandas.pydata.org/pandas-docs/stable/user_guide/timeseries.html#offset-aliases>`__.
Examples
--------
>>> pd.period_range(start='2017-01-01', end='2018-01-01', freq='M')
PeriodIndex(['2017-01', '2017-02', '2017-03', '2017-04', '2017-05',
'2017-06', '2017-06', '2017-07', '2017-08', '2017-09',
'2017-10', '2017-11', '2017-12', '2018-01'],
dtype='period[M]', freq='M')
If ``start`` or ``end`` are ``Period`` objects, they will be used as anchor
endpoints for a ``PeriodIndex`` with frequency matching that of the
``period_range`` constructor.
>>> pd.period_range(start=pd.Period('2017Q1', freq='Q'),
... end=pd.Period('2017Q2', freq='Q'), freq='M')
PeriodIndex(['2017-03', '2017-04', '2017-05', '2017-06'],
dtype='period[M]', freq='M')
"""
if com.count_not_none(start, end, periods) != 2:
raise ValueError(
"Of the three parameters: start, end, and periods, "
"exactly two must be specified"
)
if freq is None and (not isinstance(start, Period) and not isinstance(end, Period)):
freq = "D"
data, freq = PeriodArray._generate_range(start, end, periods, freq, fields={})
data = PeriodArray(data, freq=freq)
return PeriodIndex(data, name=name)
from datetime import datetime, timedelta
from typing import Any
import weakref
import numpy as np
from pandas._libs import index as libindex
from pandas._libs.tslibs import NaT, frequencies as libfrequencies, resolution
from pandas._libs.tslibs.parsing import parse_time_string
from pandas._libs.tslibs.period import Period
from pandas.util._decorators import Appender, cache_readonly
from pandas.core.dtypes.common import (
ensure_platform_int,
is_bool_dtype,
is_datetime64_any_dtype,
is_dtype_equal,
is_float,
is_integer,
is_integer_dtype,
is_list_like,
is_object_dtype,
pandas_dtype,
)
from pandas.core.accessor import delegate_names
from pandas.core.arrays.period import (
PeriodArray,
period_array,
raise_on_incompatible,
validate_dtype_freq,
)
import pandas.core.common as com
import pandas.core.indexes.base as ibase
from pandas.core.indexes.base import (
_index_shared_docs,
ensure_index,
maybe_extract_name,
)
from pandas.core.indexes.datetimelike import (
DatetimeIndexOpsMixin,
DatetimelikeDelegateMixin,
)
from pandas.core.indexes.datetimes import DatetimeIndex, Index
from pandas.core.indexes.numeric import Int64Index
from pandas.core.ops import get_op_result_name
from pandas.core.tools.datetimes import DateParseError
from pandas.tseries import frequencies
from pandas.tseries.offsets import DateOffset, Tick
_index_doc_kwargs = dict(ibase._index_doc_kwargs)
_index_doc_kwargs.update(dict(target_klass="PeriodIndex or list of Periods"))
# --- Period index sketch
def _new_PeriodIndex(cls, **d):
# GH13277 for unpickling
values = d.pop("data")
if values.dtype == "int64":
freq = d.pop("freq", None)
values = PeriodArray(values, freq=freq)
return cls._simple_new(values, **d)
else:
return cls(values, **d)
class PeriodDelegateMixin(DatetimelikeDelegateMixin):
"""
Delegate from PeriodIndex to PeriodArray.
"""
_raw_methods = {"_format_native_types"}
_raw_properties = {"is_leap_year", "freq"}
_delegated_properties = PeriodArray._datetimelike_ops + list(_raw_properties)
_delegated_methods = set(PeriodArray._datetimelike_methods) | _raw_methods
@delegate_names(PeriodArray, PeriodDelegateMixin._delegated_properties, typ="property")
@delegate_names(
PeriodArray, PeriodDelegateMixin._delegated_methods, typ="method", overwrite=True
)
class PeriodIndex(DatetimeIndexOpsMixin, Int64Index, PeriodDelegateMixin):
"""
Immutable ndarray holding ordinal values indicating regular periods in time.
Index keys are boxed to Period objects which carries the metadata (eg,
frequency information).
Parameters
----------
data : array-like (1d int np.ndarray or PeriodArray), optional
Optional period-like data to construct index with.
copy : bool
Make a copy of input ndarray.
freq : str or period object, optional
One of pandas period strings or corresponding objects
year : int, array, or Series, default None
month : int, array, or Series, default None
quarter : int, array, or Series, default None
day : int, array, or Series, default None
hour : int, array, or Series, default None
minute : int, array, or Series, default None
second : int, array, or Series, default None
tz : object, default None
Timezone for converting datetime64 data to Periods.
dtype : str or PeriodDtype, default None
Attributes
----------
day
dayofweek
dayofyear
days_in_month
daysinmonth
end_time
freq
freqstr
hour
is_leap_year
minute
month
quarter
qyear
second
start_time
week
weekday
weekofyear
year
Methods
-------
asfreq
strftime
to_timestamp
See Also
--------
Index : The base pandas Index type.
Period : Represents a period of time.
DatetimeIndex : Index with datetime64 data.
TimedeltaIndex : Index of timedelta64 data.
period_range : Create a fixed-frequency PeriodIndex.
Examples
--------
>>> idx = pd.PeriodIndex(year=year_arr, quarter=q_arr)
"""
_typ = "periodindex"
_attributes = ["name", "freq"]
# define my properties & methods for delegation
_is_numeric_dtype = False
_infer_as_myclass = True
_data: PeriodArray
_engine_type = libindex.PeriodEngine
_supports_partial_string_indexing = True
# ------------------------------------------------------------------------
# Index Constructors
def __new__(
cls,
data=None,
ordinal=None,
freq=None,
tz=None,
dtype=None,
copy=False,
name=None,
**fields,
):
valid_field_set = {
"year",
"month",
"day",
"quarter",
"hour",
"minute",
"second",
}
if not set(fields).issubset(valid_field_set):
argument = list(set(fields) - valid_field_set)[0]
raise TypeError(f"__new__() got an unexpected keyword argument {argument}")
name = maybe_extract_name(name, data, cls)
if data is None and ordinal is None:
# range-based.
data, freq2 = PeriodArray._generate_range(None, None, None, freq, fields)
# PeriodArray._generate range does validation that fields is
# empty when really using the range-based constructor.
freq = freq2
data = PeriodArray(data, freq=freq)
else:
freq = validate_dtype_freq(dtype, freq)
# PeriodIndex allow PeriodIndex(period_index, freq=different)
# Let's not encourage that kind of behavior in PeriodArray.
if freq and isinstance(data, cls) and data.freq != freq:
# TODO: We can do some of these with no-copy / coercion?
# e.g. D -> 2D seems to be OK
data = data.asfreq(freq)
if data is None and ordinal is not None:
# we strangely ignore `ordinal` if data is passed.
ordinal = np.asarray(ordinal, dtype=np.int64)
data = PeriodArray(ordinal, freq)
else:
# don't pass copy here, since we copy later.
data = period_array(data=data, freq=freq)
if copy:
data = data.copy()
return cls._simple_new(data, name=name)
@classmethod
def _simple_new(cls, values, name=None, freq=None, **kwargs):
"""
Create a new PeriodIndex.
Parameters
----------
values : PeriodArray
Values that can be converted to a PeriodArray without inference
or coercion.
"""
assert isinstance(values, PeriodArray), type(values)
assert freq is None or freq == values.freq, (freq, values.freq)
result = object.__new__(cls)
result._data = values
# For groupby perf. See note in indexes/base about _index_data
result._index_data = values._data
result.name = name
result._reset_identity()
return result
# ------------------------------------------------------------------------
# Data
@property
def values(self):
return np.asarray(self)
def _shallow_copy(self, values=None, **kwargs):
# TODO: simplify, figure out type of values
if values is None:
values = self._data
if isinstance(values, type(self)):
values = values._data
if not isinstance(values, PeriodArray):
if isinstance(values, np.ndarray) and values.dtype == "i8":
values = PeriodArray(values, freq=self.freq)
else:
# GH#30713 this should never be reached
raise TypeError(type(values), getattr(values, "dtype", None))
# We don't allow changing `freq` in _shallow_copy.
validate_dtype_freq(self.dtype, kwargs.get("freq"))
attributes = self._get_attributes_dict()
attributes.update(kwargs)
if not len(values) and "dtype" not in kwargs:
attributes["dtype"] = self.dtype
return self._simple_new(values, **attributes)
def _shallow_copy_with_infer(self, values=None, **kwargs):
""" we always want to return a PeriodIndex """
return self._shallow_copy(values=values, **kwargs)
@property
def _box_func(self):
"""Maybe box an ordinal or Period"""
# TODO(DatetimeArray): Avoid double-boxing
# PeriodArray takes care of boxing already, so we need to check
# whether we're given an ordinal or a Period. It seems like some
# places outside of indexes/period.py are calling this _box_func,
# but passing data that's already boxed.
def func(x):
if isinstance(x, Period) or x is NaT:
return x
else:
return Period._from_ordinal(ordinal=x, freq=self.freq)
return func
def _maybe_convert_timedelta(self, other):
"""
Convert timedelta-like input to an integer multiple of self.freq
Parameters
----------
other : timedelta, np.timedelta64, DateOffset, int, np.ndarray
Returns
-------
converted : int, np.ndarray[int64]
Raises
------
IncompatibleFrequency : if the input cannot be written as a multiple
of self.freq. Note IncompatibleFrequency subclasses ValueError.
"""
if isinstance(other, (timedelta, np.timedelta64, Tick, np.ndarray)):
offset = frequencies.to_offset(self.freq.rule_code)
if isinstance(offset, Tick):
# _check_timedeltalike_freq_compat will raise if incompatible
delta = self._data._check_timedeltalike_freq_compat(other)
return delta
elif isinstance(other, DateOffset):
freqstr = other.rule_code
base = libfrequencies.get_base_alias(freqstr)
if base == self.freq.rule_code:
return other.n
raise raise_on_incompatible(self, other)
elif is_integer(other):
# integer is passed to .shift via
# _add_datetimelike_methods basically
# but ufunc may pass integer to _add_delta
return other
# raise when input doesn't have freq
raise raise_on_incompatible(self, None)
# ------------------------------------------------------------------------
# Rendering Methods
def _mpl_repr(self):
# how to represent ourselves to matplotlib
return self.astype(object).values
@property
def _formatter_func(self):
return self.array._formatter(boxed=False)
# ------------------------------------------------------------------------
# Indexing
@cache_readonly
def _engine(self):
# To avoid a reference cycle, pass a weakref of self to _engine_type.
period = weakref.ref(self)
return self._engine_type(period, len(self))
@Appender(_index_shared_docs["contains"])
def __contains__(self, key: Any) -> bool:
if isinstance(key, Period):
if key.freq != self.freq:
return False
else:
return key.ordinal in self._engine
else:
hash(key)
try:
self.get_loc(key)
return True
except KeyError:
return False
@cache_readonly
def _int64index(self):
return Int64Index._simple_new(self.asi8, name=self.name)
# ------------------------------------------------------------------------
# Index Methods
def __array__(self, dtype=None) -> np.ndarray:
if is_integer_dtype(dtype):
return self.asi8
else:
return self.astype(object).values
def __array_wrap__(self, result, context=None):
"""
Gets called after a ufunc. Needs additional handling as
PeriodIndex stores internal data as int dtype
Replace this to __numpy_ufunc__ in future version
"""
if isinstance(context, tuple) and len(context) > 0:
func = context[0]
if func is np.add:
pass
elif func is np.subtract:
name = self.name
left = context[1][0]
right = context[1][1]
if isinstance(left, PeriodIndex) and isinstance(right, PeriodIndex):
name = left.name if left.name == right.name else None
return Index(result, name=name)
elif isinstance(left, Period) or isinstance(right, Period):
return Index(result, name=name)
elif isinstance(func, np.ufunc):
if "M->M" not in func.types:
msg = f"ufunc '{func.__name__}' not supported for the PeriodIndex"
# This should be TypeError, but TypeError cannot be raised
# from here because numpy catches.
raise ValueError(msg)
if is_bool_dtype(result):
return result
# the result is object dtype array of Period
# cannot pass _simple_new as it is
return type(self)(result, freq=self.freq, name=self.name)
def asof_locs(self, where, mask):
"""
where : array of timestamps
mask : array of booleans where data is not NA
"""
where_idx = where
if isinstance(where_idx, DatetimeIndex):
where_idx = PeriodIndex(where_idx.values, freq=self.freq)
locs = self._ndarray_values[mask].searchsorted(
where_idx._ndarray_values, side="right"
)
locs = np.where(locs > 0, locs - 1, 0)
result = np.arange(len(self))[mask].take(locs)
first = mask.argmax()
result[
(locs == 0) & (where_idx._ndarray_values < self._ndarray_values[first])
] = -1
return result
@Appender(_index_shared_docs["astype"])
def astype(self, dtype, copy=True, how="start"):
dtype = pandas_dtype(dtype)
if is_datetime64_any_dtype(dtype):
# 'how' is index-specific, isn't part of the EA interface.
tz = getattr(dtype, "tz", None)
return self.to_timestamp(how=how).tz_localize(tz)
# TODO: should probably raise on `how` here, so we don't ignore it.
return super().astype(dtype, copy=copy)
@property
def is_full(self) -> bool:
"""
Returns True if this PeriodIndex is range-like in that all Periods
between start and end are present, in order.
"""
if len(self) == 0:
return True
if not self.is_monotonic:
raise ValueError("Index is not monotonic")
values = self.asi8
return ((values[1:] - values[:-1]) < 2).all()
@property
def inferred_type(self) -> str:
# b/c data is represented as ints make sure we can't have ambiguous
# indexing
return "period"
def get_value(self, series, key):
"""
Fast lookup of value from 1-dimensional ndarray. Only use this if you
know what you're doing
"""
if is_integer(key):
return series.iat[key]
if isinstance(key, str):
try:
loc = self._get_string_slice(key)
return series[loc]
except (TypeError, ValueError, OverflowError):
pass
asdt, reso = parse_time_string(key, self.freq)
grp = resolution.Resolution.get_freq_group(reso)
freqn = resolution.get_freq_group(self.freq)
# _get_string_slice will handle cases where grp < freqn
assert grp >= freqn
if grp == freqn:
key = Period(asdt, freq=self.freq)
loc = self.get_loc(key)
return series.iloc[loc]
else:
raise KeyError(key)
elif isinstance(key, Period) or key is NaT:
ordinal = key.ordinal if key is not NaT else NaT.value
loc = self._engine.get_loc(ordinal)
return series[loc]
# slice, PeriodIndex, np.ndarray, List[Period]
value = Index.get_value(self, series, key)
return com.maybe_box(self, value, series, key)
@Appender(_index_shared_docs["get_indexer"] % _index_doc_kwargs)
def get_indexer(self, target, method=None, limit=None, tolerance=None):
target = ensure_index(target)
if isinstance(target, PeriodIndex):
if target.freq != self.freq:
# No matches
no_matches = -1 * np.ones(self.shape, dtype=np.intp)
return no_matches
target = target.asi8
self_index = self._int64index
else:
self_index = self
if tolerance is not None:
tolerance = self._convert_tolerance(tolerance, target)
return Index.get_indexer(self_index, target, method, limit, tolerance)
@Appender(_index_shared_docs["get_indexer_non_unique"] % _index_doc_kwargs)
def get_indexer_non_unique(self, target):
target = ensure_index(target)
if isinstance(target, PeriodIndex):
if target.freq != self.freq:
no_matches = -1 * np.ones(self.shape, dtype=np.intp)
return no_matches, no_matches
target = target.asi8
indexer, missing = self._int64index.get_indexer_non_unique(target)
return ensure_platform_int(indexer), missing
def get_loc(self, key, method=None, tolerance=None):
"""
Get integer location for requested label.
Parameters
----------
key : Period, NaT, str, or datetime
String or datetime key must be parseable as Period.
Returns
-------
loc : int or ndarray[int64]
Raises
------
KeyError
Key is not present in the index.
TypeError
If key is listlike or otherwise not hashable.
"""
if isinstance(key, str):
try:
loc = self._get_string_slice(key)
return loc
except (TypeError, ValueError):
pass
try:
asdt, reso = parse_time_string(key, self.freq)
except DateParseError:
# A string with invalid format
raise KeyError(f"Cannot interpret '{key}' as period")
grp = resolution.Resolution.get_freq_group(reso)
freqn = resolution.get_freq_group(self.freq)
# _get_string_slice will handle cases where grp < freqn
assert grp >= freqn
if grp == freqn:
key = Period(asdt, freq=self.freq)
loc = self.get_loc(key, method=method, tolerance=tolerance)
return loc
elif method is None:
raise KeyError(key)
else:
key = asdt
elif is_integer(key):
# Period constructor will cast to string, which we dont want
raise KeyError(key)
try:
key = Period(key, freq=self.freq)
except ValueError:
# we cannot construct the Period
# as we have an invalid type
if is_list_like(key):
raise TypeError(f"'{key}' is an invalid key")
raise KeyError(key)
ordinal = key.ordinal if key is not NaT else key.value
try:
return self._engine.get_loc(ordinal)
except KeyError:
try:
if tolerance is not None:
tolerance = self._convert_tolerance(tolerance, np.asarray(key))
return self._int64index.get_loc(ordinal, method, tolerance)
except KeyError:
raise KeyError(key)
def _maybe_cast_slice_bound(self, label, side, kind):
"""
If label is a string or a datetime, cast it to Period.ordinal according
to resolution.
Parameters
----------
label : object
side : {'left', 'right'}
kind : {'loc', 'getitem'}
Returns
-------
bound : Period or object
Notes
-----
Value of `side` parameter should be validated in caller.
"""
assert kind in ["loc", "getitem"]
if isinstance(label, datetime):
return Period(label, freq=self.freq)
elif isinstance(label, str):
try:
parsed, reso = parse_time_string(label, self.freq)
bounds = self._parsed_string_to_bounds(reso, parsed)
return bounds[0 if side == "left" else 1]
except ValueError:
# string cannot be parsed as datetime-like
# TODO: we need tests for this case
raise KeyError(label)
elif is_integer(label) or is_float(label):
self._invalid_indexer("slice", label)
return label
def _parsed_string_to_bounds(self, reso: str, parsed: datetime):
if reso not in ["year", "month", "quarter", "day", "hour", "minute", "second"]:
raise KeyError(reso)
grp = resolution.Resolution.get_freq_group(reso)
iv = Period(parsed, freq=(grp, 1))
return (iv.asfreq(self.freq, how="start"), iv.asfreq(self.freq, how="end"))
def _get_string_slice(self, key: str, use_lhs: bool = True, use_rhs: bool = True):
# TODO: Check for non-True use_lhs/use_rhs
parsed, reso = parse_time_string(key, self.freq)
grp = resolution.Resolution.get_freq_group(reso)
freqn = resolution.get_freq_group(self.freq)
if not grp < freqn:
# TODO: we used to also check for
# reso in ["day", "hour", "minute", "second"]
# why is that check not needed?
raise ValueError(key)
t1, t2 = self._parsed_string_to_bounds(reso, parsed)
i8vals = self.asi8
if self.is_monotonic:
# we are out of range
if len(self) and (
(use_lhs and t1 < self[0] and t2 < self[0])
or ((use_rhs and t1 > self[-1] and t2 > self[-1]))
):
raise KeyError(key)
# TODO: does this depend on being monotonic _increasing_?
# If so, DTI will also be affected.
# a monotonic (sorted) series can be sliced
# Use asi8.searchsorted to avoid re-validating Periods
left = i8vals.searchsorted(t1.ordinal, side="left") if use_lhs else None
right = i8vals.searchsorted(t2.ordinal, side="right") if use_rhs else None
return slice(left, right)
else:
lhs_mask = (i8vals >= t1.ordinal) if use_lhs else True
rhs_mask = (i8vals <= t2.ordinal) if use_rhs else True
# try to find a the dates
return (lhs_mask & rhs_mask).nonzero()[0]
def _convert_tolerance(self, tolerance, target):
tolerance = DatetimeIndexOpsMixin._convert_tolerance(self, tolerance, target)
if target.size != tolerance.size and tolerance.size > 1:
raise ValueError("list-like tolerance size must match target index size")
return self._maybe_convert_timedelta(tolerance)
def insert(self, loc, item):
if not isinstance(item, Period) or self.freq != item.freq:
return self.astype(object).insert(loc, item)
idx = np.concatenate(
(self[:loc].asi8, np.array([item.ordinal]), self[loc:].asi8)
)
return self._shallow_copy(idx)
def join(self, other, how="left", level=None, return_indexers=False, sort=False):
"""
See Index.join
"""
self._assert_can_do_setop(other)
if not isinstance(other, PeriodIndex):
return self.astype(object).join(
other, how=how, level=level, return_indexers=return_indexers, sort=sort
)
result = Int64Index.join(
self,
other,
how=how,
level=level,
return_indexers=return_indexers,
sort=sort,
)
if return_indexers:
result, lidx, ridx = result
return self._apply_meta(result), lidx, ridx
return self._apply_meta(result)
# ------------------------------------------------------------------------
# Set Operation Methods
def _assert_can_do_setop(self, other):
super()._assert_can_do_setop(other)
# *Can't* use PeriodIndexes of different freqs
# *Can* use PeriodIndex/DatetimeIndex
if isinstance(other, PeriodIndex) and self.freq != other.freq:
raise raise_on_incompatible(self, other)
def intersection(self, other, sort=False):
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
res_name = get_op_result_name(self, other)
other = ensure_index(other)
if self.equals(other):
return self._get_reconciled_name_object(other)
if not is_dtype_equal(self.dtype, other.dtype):
# TODO: fastpath for if we have a different PeriodDtype
this = self.astype("O")
other = other.astype("O")
return this.intersection(other, sort=sort)
i8self = Int64Index._simple_new(self.asi8)
i8other = Int64Index._simple_new(other.asi8)
i8result = i8self.intersection(i8other, sort=sort)
result = self._shallow_copy(np.asarray(i8result, dtype=np.int64), name=res_name)
return result
def difference(self, other, sort=None):
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
res_name = get_op_result_name(self, other)
other = ensure_index(other)
if self.equals(other):
# pass an empty PeriodArray with the appropriate dtype
return self._shallow_copy(self._data[:0])
if is_object_dtype(other):
return self.astype(object).difference(other).astype(self.dtype)
elif not is_dtype_equal(self.dtype, other.dtype):
return self
i8self = Int64Index._simple_new(self.asi8)
i8other = Int64Index._simple_new(other.asi8)
i8result = i8self.difference(i8other, sort=sort)
result = self._shallow_copy(np.asarray(i8result, dtype=np.int64), name=res_name)
return result
def _union(self, other, sort):
if not len(other) or self.equals(other) or not len(self):
return super()._union(other, sort=sort)
# We are called by `union`, which is responsible for this validation
assert isinstance(other, type(self))
if not is_dtype_equal(self.dtype, other.dtype):
this = self.astype("O")
other = other.astype("O")
return this._union(other, sort=sort)
i8self = Int64Index._simple_new(self.asi8)
i8other = Int64Index._simple_new(other.asi8)
i8result = i8self._union(i8other, sort=sort)
res_name = get_op_result_name(self, other)
result = self._shallow_copy(np.asarray(i8result, dtype=np.int64), name=res_name)
return result
# ------------------------------------------------------------------------
def _apply_meta(self, rawarr):
if not isinstance(rawarr, PeriodIndex):
if not isinstance(rawarr, PeriodArray):
rawarr = PeriodArray(rawarr, freq=self.freq)
rawarr = PeriodIndex._simple_new(rawarr, name=self.name)
return rawarr
def memory_usage(self, deep=False):
result = super().memory_usage(deep=deep)
if hasattr(self, "_cache") and "_int64index" in self._cache:
result += self._int64index.memory_usage(deep=deep)
return result
PeriodIndex._add_numeric_methods_disabled()
PeriodIndex._add_logical_methods_disabled()
def period_range(
start=None, end=None, periods=None, freq=None, name=None
) -> PeriodIndex:
"""
Return a fixed frequency PeriodIndex.
The day (calendar) is the default frequency.
Parameters
----------
start : str or period-like, default None
Left bound for generating periods.
end : str or period-like, default None
Right bound for generating periods.
periods : int, default None
Number of periods to generate.
freq : str or DateOffset, optional
Frequency alias. By default the freq is taken from `start` or `end`
if those are Period objects. Otherwise, the default is ``"D"`` for
daily frequency.
name : str, default None
Name of the resulting PeriodIndex.
Returns
-------
PeriodIndex
Notes
-----
Of the three parameters: ``start``, ``end``, and ``periods``, exactly two
must be specified.
To learn more about the frequency strings, please see `this link
<https://pandas.pydata.org/pandas-docs/stable/user_guide/timeseries.html#offset-aliases>`__.
Examples
--------
>>> pd.period_range(start='2017-01-01', end='2018-01-01', freq='M')
PeriodIndex(['2017-01', '2017-02', '2017-03', '2017-04', '2017-05',
'2017-06', '2017-06', '2017-07', '2017-08', '2017-09',
'2017-10', '2017-11', '2017-12', '2018-01'],
dtype='period[M]', freq='M')
If ``start`` or ``end`` are ``Period`` objects, they will be used as anchor
endpoints for a ``PeriodIndex`` with frequency matching that of the
``period_range`` constructor.
>>> pd.period_range(start=pd.Period('2017Q1', freq='Q'),
... end=pd.Period('2017Q2', freq='Q'), freq='M')
PeriodIndex(['2017-03', '2017-04', '2017-05', '2017-06'],
dtype='period[M]', freq='M')
"""
if com.count_not_none(start, end, periods) != 2:
raise ValueError(
"Of the three parameters: start, end, and periods, "
"exactly two must be specified"
)
if freq is None and (not isinstance(start, Period) and not isinstance(end, Period)):
freq = "D"
data, freq = PeriodArray._generate_range(start, end, periods, freq, fields={})
data = PeriodArray(data, freq=freq)
return PeriodIndex(data, name=name)
| BugsInPy/BugsInPy/temp/projects/pandas/bug-75-fixed/pandas/pandas/core/indexes/period.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-75-buggy/pandas/pandas/core/indexes/period.py |
pandas-bug-67 | from datetime import datetime, timedelta
import functools
import inspect
import re
from typing import Any, List
import warnings
import numpy as np
from pandas._libs import NaT, algos as libalgos, lib, tslib, writers
from pandas._libs.index import convert_scalar
import pandas._libs.internals as libinternals
from pandas._libs.tslibs import Timedelta, conversion
from pandas._libs.tslibs.timezones import tz_compare
from pandas.util._validators import validate_bool_kwarg
from pandas.core.dtypes.cast import (
astype_nansafe,
find_common_type,
infer_dtype_from,
infer_dtype_from_scalar,
maybe_downcast_numeric,
maybe_downcast_to_dtype,
maybe_infer_dtype_type,
maybe_promote,
maybe_upcast,
soft_convert_objects,
)
from pandas.core.dtypes.common import (
_NS_DTYPE,
_TD_DTYPE,
ensure_platform_int,
is_bool_dtype,
is_categorical,
is_categorical_dtype,
is_datetime64_dtype,
is_datetime64tz_dtype,
is_dtype_equal,
is_extension_array_dtype,
is_float_dtype,
is_integer,
is_integer_dtype,
is_interval_dtype,
is_list_like,
is_object_dtype,
is_period_dtype,
is_re,
is_re_compilable,
is_sparse,
is_timedelta64_dtype,
pandas_dtype,
)
from pandas.core.dtypes.concat import concat_categorical, concat_datetime
from pandas.core.dtypes.dtypes import CategoricalDtype, ExtensionDtype
from pandas.core.dtypes.generic import (
ABCDataFrame,
ABCExtensionArray,
ABCPandasArray,
ABCSeries,
)
from pandas.core.dtypes.missing import (
_isna_compat,
array_equivalent,
is_valid_nat_for_dtype,
isna,
)
import pandas.core.algorithms as algos
from pandas.core.arrays import (
Categorical,
DatetimeArray,
ExtensionArray,
PandasArray,
PandasDtype,
TimedeltaArray,
)
from pandas.core.base import PandasObject
import pandas.core.common as com
from pandas.core.construction import extract_array
from pandas.core.indexers import (
check_setitem_lengths,
is_empty_indexer,
is_scalar_indexer,
)
import pandas.core.missing as missing
from pandas.core.nanops import nanpercentile
from pandas.io.formats.printing import pprint_thing
class Block(PandasObject):
"""
Canonical n-dimensional unit of homogeneous dtype contained in a pandas
data structure
Index-ignorant; let the container take care of that
"""
__slots__ = ["_mgr_locs", "values", "ndim"]
is_numeric = False
is_float = False
is_integer = False
is_complex = False
is_datetime = False
is_datetimetz = False
is_timedelta = False
is_bool = False
is_object = False
is_categorical = False
is_extension = False
_can_hold_na = False
_can_consolidate = True
_verify_integrity = True
_validate_ndim = True
_ftype = "dense"
_concatenator = staticmethod(np.concatenate)
def __init__(self, values, placement, ndim=None):
self.ndim = self._check_ndim(values, ndim)
self.mgr_locs = placement
self.values = values
if self._validate_ndim and self.ndim and len(self.mgr_locs) != len(self.values):
raise ValueError(
f"Wrong number of items passed {len(self.values)}, "
f"placement implies {len(self.mgr_locs)}"
)
def _check_ndim(self, values, ndim):
"""
ndim inference and validation.
Infers ndim from 'values' if not provided to __init__.
Validates that values.ndim and ndim are consistent if and only if
the class variable '_validate_ndim' is True.
Parameters
----------
values : array-like
ndim : int or None
Returns
-------
ndim : int
Raises
------
ValueError : the number of dimensions do not match
"""
if ndim is None:
ndim = values.ndim
if self._validate_ndim and values.ndim != ndim:
raise ValueError(
"Wrong number of dimensions. "
f"values.ndim != ndim [{values.ndim} != {ndim}]"
)
return ndim
@property
def _holder(self):
"""The array-like that can hold the underlying values.
None for 'Block', overridden by subclasses that don't
use an ndarray.
"""
return None
@property
def _consolidate_key(self):
return (self._can_consolidate, self.dtype.name)
@property
def _is_single_block(self):
return self.ndim == 1
@property
def is_view(self):
""" return a boolean if I am possibly a view """
return self.values.base is not None
@property
def is_datelike(self):
""" return True if I am a non-datelike """
return self.is_datetime or self.is_timedelta
def is_categorical_astype(self, dtype):
"""
validate that we have a astypeable to categorical,
returns a boolean if we are a categorical
"""
if dtype is Categorical or dtype is CategoricalDtype:
# this is a pd.Categorical, but is not
# a valid type for astypeing
raise TypeError(f"invalid type {dtype} for astype")
elif is_categorical_dtype(dtype):
return True
return False
def external_values(self):
"""
The array that Series.values returns (public attribute).
This has some historical constraints, and is overridden in block
subclasses to return the correct array (e.g. period returns
object ndarray and datetimetz a datetime64[ns] ndarray instead of
proper extension array).
"""
return self.values
def internal_values(self):
"""
The array that Series._values returns (internal values).
"""
return self.values
def array_values(self) -> ExtensionArray:
"""
The array that Series.array returns. Always an ExtensionArray.
"""
return PandasArray(self.values)
def get_values(self, dtype=None):
"""
return an internal format, currently just the ndarray
this is often overridden to handle to_dense like operations
"""
if is_object_dtype(dtype):
return self.values.astype(object)
return self.values
def get_block_values(self, dtype=None):
"""
This is used in the JSON C code
"""
return self.get_values(dtype=dtype)
def to_dense(self):
return self.values.view()
@property
def fill_value(self):
return np.nan
@property
def mgr_locs(self):
return self._mgr_locs
@mgr_locs.setter
def mgr_locs(self, new_mgr_locs):
if not isinstance(new_mgr_locs, libinternals.BlockPlacement):
new_mgr_locs = libinternals.BlockPlacement(new_mgr_locs)
self._mgr_locs = new_mgr_locs
@property
def array_dtype(self):
""" the dtype to return if I want to construct this block as an
array
"""
return self.dtype
def make_block(self, values, placement=None) -> "Block":
"""
Create a new block, with type inference propagate any values that are
not specified
"""
if placement is None:
placement = self.mgr_locs
return make_block(values, placement=placement, ndim=self.ndim)
def make_block_same_class(self, values, placement=None, ndim=None):
""" Wrap given values in a block of same type as self. """
if placement is None:
placement = self.mgr_locs
if ndim is None:
ndim = self.ndim
return make_block(values, placement=placement, ndim=ndim, klass=type(self))
def __repr__(self) -> str:
# don't want to print out all of the items here
name = type(self).__name__
if self._is_single_block:
result = f"{name}: {len(self)} dtype: {self.dtype}"
else:
shape = " x ".join(pprint_thing(s) for s in self.shape)
result = (
f"{name}: {pprint_thing(self.mgr_locs.indexer)}, "
f"{shape}, dtype: {self.dtype}"
)
return result
def __len__(self) -> int:
return len(self.values)
def __getstate__(self):
return self.mgr_locs.indexer, self.values
def __setstate__(self, state):
self.mgr_locs = libinternals.BlockPlacement(state[0])
self.values = state[1]
self.ndim = self.values.ndim
def _slice(self, slicer):
""" return a slice of my values """
return self.values[slicer]
def getitem_block(self, slicer, new_mgr_locs=None):
"""
Perform __getitem__-like, return result as block.
As of now, only supports slices that preserve dimensionality.
"""
if new_mgr_locs is None:
if isinstance(slicer, tuple):
axis0_slicer = slicer[0]
else:
axis0_slicer = slicer
new_mgr_locs = self.mgr_locs[axis0_slicer]
new_values = self._slice(slicer)
if self._validate_ndim and new_values.ndim != self.ndim:
raise ValueError("Only same dim slicing is allowed")
return self.make_block_same_class(new_values, new_mgr_locs)
@property
def shape(self):
return self.values.shape
@property
def dtype(self):
return self.values.dtype
@property
def ftype(self):
if getattr(self.values, "_pandas_ftype", False):
dtype = self.dtype.subtype
else:
dtype = self.dtype
return f"{dtype}:{self._ftype}"
def merge(self, other):
return _merge_blocks([self, other])
def concat_same_type(self, to_concat, placement=None):
"""
Concatenate list of single blocks of the same type.
"""
values = self._concatenator(
[blk.values for blk in to_concat], axis=self.ndim - 1
)
return self.make_block_same_class(
values, placement=placement or slice(0, len(values), 1)
)
def iget(self, i):
return self.values[i]
def set(self, locs, values):
"""
Modify Block in-place with new item value
Returns
-------
None
"""
self.values[locs] = values
def delete(self, loc):
"""
Delete given loc(-s) from block in-place.
"""
self.values = np.delete(self.values, loc, 0)
self.mgr_locs = self.mgr_locs.delete(loc)
def apply(self, func, **kwargs) -> List["Block"]:
""" apply the function to my values; return a block if we are not
one
"""
with np.errstate(all="ignore"):
result = func(self.values, **kwargs)
return self._split_op_result(result)
def _split_op_result(self, result) -> List["Block"]:
# See also: split_and_operate
if is_extension_array_dtype(result) and result.ndim > 1:
# if we get a 2D ExtensionArray, we need to split it into 1D pieces
nbs = []
for i, loc in enumerate(self.mgr_locs):
vals = result[i]
nv = _block_shape(vals, ndim=self.ndim)
block = self.make_block(values=nv, placement=[loc])
nbs.append(block)
return nbs
if not isinstance(result, Block):
result = self.make_block(values=_block_shape(result, ndim=self.ndim))
return [result]
def fillna(self, value, limit=None, inplace=False, downcast=None):
""" fillna on the block with the value. If we fail, then convert to
ObjectBlock and try again
"""
inplace = validate_bool_kwarg(inplace, "inplace")
mask = isna(self.values)
if limit is not None:
limit = libalgos._validate_limit(None, limit=limit)
mask[mask.cumsum(self.ndim - 1) > limit] = False
if not self._can_hold_na:
if inplace:
return self
else:
return self.copy()
if self._can_hold_element(value):
# equivalent: _try_coerce_args(value) would not raise
blocks = self.putmask(mask, value, inplace=inplace)
return self._maybe_downcast(blocks, downcast)
# we can't process the value, but nothing to do
if not mask.any():
return self if inplace else self.copy()
# operate column-by-column
def f(mask, val, idx):
block = self.coerce_to_target_dtype(value)
# slice out our block
if idx is not None:
# i.e. self.ndim == 2
block = block.getitem_block(slice(idx, idx + 1))
return block.fillna(value, limit=limit, inplace=inplace, downcast=None)
return self.split_and_operate(None, f, inplace)
def split_and_operate(self, mask, f, inplace: bool):
"""
split the block per-column, and apply the callable f
per-column, return a new block for each. Handle
masking which will not change a block unless needed.
Parameters
----------
mask : 2-d boolean mask
f : callable accepting (1d-mask, 1d values, indexer)
inplace : boolean
Returns
-------
list of blocks
"""
if mask is None:
mask = np.broadcast_to(True, shape=self.shape)
new_values = self.values
def make_a_block(nv, ref_loc):
if isinstance(nv, list):
assert len(nv) == 1, nv
assert isinstance(nv[0], Block)
block = nv[0]
else:
# Put back the dimension that was taken from it and make
# a block out of the result.
nv = _block_shape(nv, ndim=self.ndim)
block = self.make_block(values=nv, placement=ref_loc)
return block
# ndim == 1
if self.ndim == 1:
if mask.any():
nv = f(mask, new_values, None)
else:
nv = new_values if inplace else new_values.copy()
block = make_a_block(nv, self.mgr_locs)
return [block]
# ndim > 1
new_blocks = []
for i, ref_loc in enumerate(self.mgr_locs):
m = mask[i]
v = new_values[i]
# need a new block
if m.any():
nv = f(m, v, i)
else:
nv = v if inplace else v.copy()
block = make_a_block(nv, [ref_loc])
new_blocks.append(block)
return new_blocks
def _maybe_downcast(self, blocks: List["Block"], downcast=None) -> List["Block"]:
# no need to downcast our float
# unless indicated
if downcast is None and (
self.is_float or self.is_timedelta or self.is_datetime
):
return blocks
return _extend_blocks([b.downcast(downcast) for b in blocks])
def downcast(self, dtypes=None):
""" try to downcast each item to the dict of dtypes if present """
# turn it off completely
if dtypes is False:
return self
values = self.values
# single block handling
if self._is_single_block:
# try to cast all non-floats here
if dtypes is None:
dtypes = "infer"
nv = maybe_downcast_to_dtype(values, dtypes)
return self.make_block(nv)
# ndim > 1
if dtypes is None:
return self
if not (dtypes == "infer" or isinstance(dtypes, dict)):
raise ValueError(
"downcast must have a dictionary or 'infer' as its argument"
)
elif dtypes != "infer":
raise AssertionError("dtypes as dict is not supported yet")
# operate column-by-column
# this is expensive as it splits the blocks items-by-item
def f(mask, val, idx):
val = maybe_downcast_to_dtype(val, dtype="infer")
return val
return self.split_and_operate(None, f, False)
def astype(self, dtype, copy: bool = False, errors: str = "raise"):
"""
Coerce to the new dtype.
Parameters
----------
dtype : str, dtype convertible
copy : bool, default False
copy if indicated
errors : str, {'raise', 'ignore'}, default 'ignore'
- ``raise`` : allow exceptions to be raised
- ``ignore`` : suppress exceptions. On error return original object
Returns
-------
Block
"""
errors_legal_values = ("raise", "ignore")
if errors not in errors_legal_values:
invalid_arg = (
"Expected value of kwarg 'errors' to be one of "
f"{list(errors_legal_values)}. Supplied value is '{errors}'"
)
raise ValueError(invalid_arg)
if inspect.isclass(dtype) and issubclass(dtype, ExtensionDtype):
msg = (
f"Expected an instance of {dtype.__name__}, "
"but got the class instead. Try instantiating 'dtype'."
)
raise TypeError(msg)
# may need to convert to categorical
if self.is_categorical_astype(dtype):
if is_categorical_dtype(self.values):
# GH 10696/18593: update an existing categorical efficiently
return self.make_block(self.values.astype(dtype, copy=copy))
return self.make_block(Categorical(self.values, dtype=dtype))
dtype = pandas_dtype(dtype)
# astype processing
if is_dtype_equal(self.dtype, dtype):
if copy:
return self.copy()
return self
# force the copy here
if self.is_extension:
# TODO: Should we try/except this astype?
values = self.values.astype(dtype)
else:
if issubclass(dtype.type, str):
# use native type formatting for datetime/tz/timedelta
if self.is_datelike:
values = self.to_native_types()
# astype formatting
else:
values = self.get_values()
else:
values = self.get_values(dtype=dtype)
# _astype_nansafe works fine with 1-d only
vals1d = values.ravel()
try:
values = astype_nansafe(vals1d, dtype, copy=True)
except (ValueError, TypeError):
# e.g. astype_nansafe can fail on object-dtype of strings
# trying to convert to float
if errors == "raise":
raise
newb = self.copy() if copy else self
return newb
# TODO(extension)
# should we make this attribute?
if isinstance(values, np.ndarray):
values = values.reshape(self.shape)
newb = make_block(values, placement=self.mgr_locs, ndim=self.ndim)
if newb.is_numeric and self.is_numeric:
if newb.shape != self.shape:
raise TypeError(
f"cannot set astype for copy = [{copy}] for dtype "
f"({self.dtype.name} [{self.shape}]) to different shape "
f"({newb.dtype.name} [{newb.shape}])"
)
return newb
def convert(
self,
copy: bool = True,
datetime: bool = True,
numeric: bool = True,
timedelta: bool = True,
coerce: bool = False,
):
""" attempt to coerce any object types to better types return a copy
of the block (if copy = True) by definition we are not an ObjectBlock
here!
"""
return self.copy() if copy else self
def _can_hold_element(self, element: Any) -> bool:
""" require the same dtype as ourselves """
dtype = self.values.dtype.type
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return issubclass(tipo.type, dtype)
return isinstance(element, dtype)
def to_native_types(self, slicer=None, na_rep="nan", quoting=None, **kwargs):
""" convert to our native types format, slicing if desired """
values = self.get_values()
if slicer is not None:
values = values[:, slicer]
mask = isna(values)
itemsize = writers.word_len(na_rep)
if not self.is_object and not quoting and itemsize:
values = values.astype(str)
if values.dtype.itemsize / np.dtype("U1").itemsize < itemsize:
# enlarge for the na_rep
values = values.astype(f"<U{itemsize}")
else:
values = np.array(values, dtype="object")
values[mask] = na_rep
return values
# block actions #
def copy(self, deep=True):
""" copy constructor """
values = self.values
if deep:
values = values.copy()
return self.make_block_same_class(values, ndim=self.ndim)
def replace(
self, to_replace, value, inplace=False, filter=None, regex=False, convert=True
):
"""replace the to_replace value with value, possible to create new
blocks here this is just a call to putmask. regex is not used here.
It is used in ObjectBlocks. It is here for API compatibility.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
original_to_replace = to_replace
# If we cannot replace with own dtype, convert to ObjectBlock and
# retry
if not self._can_hold_element(to_replace):
if not isinstance(to_replace, list):
if inplace:
return [self]
return [self.copy()]
to_replace = [x for x in to_replace if self._can_hold_element(x)]
if not len(to_replace):
# GH#28084 avoid costly checks since we can infer
# that there is nothing to replace in this block
if inplace:
return [self]
return [self.copy()]
if len(to_replace) == 1:
# _can_hold_element checks have reduced this back to the
# scalar case and we can avoid a costly object cast
return self.replace(
to_replace[0],
value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
# GH 22083, TypeError or ValueError occurred within error handling
# causes infinite loop. Cast and retry only if not objectblock.
if is_object_dtype(self):
raise AssertionError
# try again with a compatible block
block = self.astype(object)
return block.replace(
to_replace=to_replace,
value=value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
values = self.values
if lib.is_scalar(to_replace) and isinstance(values, np.ndarray):
# The only non-DatetimeLike class that also has a non-trivial
# try_coerce_args is ObjectBlock, but that overrides replace,
# so does not get here.
to_replace = convert_scalar(values, to_replace)
mask = missing.mask_missing(values, to_replace)
if filter is not None:
filtered_out = ~self.mgr_locs.isin(filter)
mask[filtered_out.nonzero()[0]] = False
if not mask.any():
if inplace:
return [self]
return [self.copy()]
try:
blocks = self.putmask(mask, value, inplace=inplace)
# Note: it is _not_ the case that self._can_hold_element(value)
# is always true at this point. In particular, that can fail
# for:
# "2u" with bool-dtype, float-dtype
# 0.5 with int64-dtype
# np.nan with int64-dtype
except (TypeError, ValueError):
# GH 22083, TypeError or ValueError occurred within error handling
# causes infinite loop. Cast and retry only if not objectblock.
if is_object_dtype(self):
raise
assert not self._can_hold_element(value), value
# try again with a compatible block
block = self.astype(object)
return block.replace(
to_replace=original_to_replace,
value=value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
if convert:
blocks = [b.convert(numeric=False, copy=not inplace) for b in blocks]
return blocks
def _replace_single(self, *args, **kwargs):
""" no-op on a non-ObjectBlock """
return self if kwargs["inplace"] else self.copy()
def setitem(self, indexer, value):
"""
Set the value inplace, returning a a maybe different typed block.
Parameters
----------
indexer : tuple, list-like, array-like, slice
The subset of self.values to set
value : object
The value being set
Returns
-------
Block
Notes
-----
`indexer` is a direct slice/positional indexer. `value` must
be a compatible shape.
"""
transpose = self.ndim == 2
# coerce None values, if appropriate
if value is None:
if self.is_numeric:
value = np.nan
# coerce if block dtype can store value
values = self.values
if self._can_hold_element(value):
# We only get here for non-Extension Blocks, so _try_coerce_args
# is only relevant for DatetimeBlock and TimedeltaBlock
if lib.is_scalar(value):
value = convert_scalar(values, value)
else:
# current dtype cannot store value, coerce to common dtype
find_dtype = False
if hasattr(value, "dtype"):
dtype = value.dtype
find_dtype = True
elif lib.is_scalar(value) and not isna(value):
dtype, _ = infer_dtype_from_scalar(value, pandas_dtype=True)
find_dtype = True
if find_dtype:
dtype = find_common_type([values.dtype, dtype])
if not is_dtype_equal(self.dtype, dtype):
b = self.astype(dtype)
return b.setitem(indexer, value)
# value must be storeable at this moment
if is_extension_array_dtype(getattr(value, "dtype", None)):
# We need to be careful not to allow through strings that
# can be parsed to EADtypes
arr_value = value
else:
arr_value = np.array(value)
# cast the values to a type that can hold nan (if necessary)
if not self._can_hold_element(value):
dtype, _ = maybe_promote(arr_value.dtype)
values = values.astype(dtype)
if transpose:
values = values.T
# length checking
check_setitem_lengths(indexer, value, values)
exact_match = (
len(arr_value.shape)
and arr_value.shape[0] == values.shape[0]
and arr_value.size == values.size
)
if is_empty_indexer(indexer, arr_value):
# GH#8669 empty indexers
pass
elif is_scalar_indexer(indexer, arr_value):
# setting a single element for each dim and with a rhs that could
# be e.g. a list; see GH#6043
values[indexer] = value
elif (
exact_match
and is_categorical_dtype(arr_value.dtype)
and not is_categorical_dtype(values)
):
# GH25495 - If the current dtype is not categorical,
# we need to create a new categorical block
values[indexer] = value
return self.make_block(Categorical(self.values, dtype=arr_value.dtype))
# if we are an exact match (ex-broadcasting),
# then use the resultant dtype
elif exact_match:
values[indexer] = value
try:
values = values.astype(arr_value.dtype)
except ValueError:
pass
# set
else:
values[indexer] = value
if transpose:
values = values.T
block = self.make_block(values)
return block
def putmask(self, mask, new, align=True, inplace=False, axis=0, transpose=False):
""" putmask the data to the block; it is possible that we may create a
new dtype of block
return the resulting block(s)
Parameters
----------
mask : the condition to respect
new : a ndarray/object
align : boolean, perform alignment on other/cond, default is True
inplace : perform inplace modification, default is False
axis : int
transpose : boolean
Set to True if self is stored with axes reversed
Returns
-------
a list of new blocks, the result of the putmask
"""
new_values = self.values if inplace else self.values.copy()
new = getattr(new, "values", new)
mask = getattr(mask, "values", mask)
# if we are passed a scalar None, convert it here
if not is_list_like(new) and isna(new) and not self.is_object:
# FIXME: make sure we have compatible NA
new = self.fill_value
if self._can_hold_element(new):
# We only get here for non-Extension Blocks, so _try_coerce_args
# is only relevant for DatetimeBlock and TimedeltaBlock
if lib.is_scalar(new):
new = convert_scalar(new_values, new)
if transpose:
new_values = new_values.T
# If the default repeat behavior in np.putmask would go in the
# wrong direction, then explicitly repeat and reshape new instead
if getattr(new, "ndim", 0) >= 1:
if self.ndim - 1 == new.ndim and axis == 1:
new = np.repeat(new, new_values.shape[-1]).reshape(self.shape)
new = new.astype(new_values.dtype)
# we require exact matches between the len of the
# values we are setting (or is compat). np.putmask
# doesn't check this and will simply truncate / pad
# the output, but we want sane error messages
#
# TODO: this prob needs some better checking
# for 2D cases
if (
is_list_like(new)
and np.any(mask[mask])
and getattr(new, "ndim", 1) == 1
):
if mask[mask].shape[-1] == len(new):
# GH 30567
# If length of ``new`` is less than the length of ``new_values``,
# `np.putmask` would first repeat the ``new`` array and then
# assign the masked values hence produces incorrect result.
# `np.place` on the other hand uses the ``new`` values at it is
# to place in the masked locations of ``new_values``
np.place(new_values, mask, new)
elif mask.shape[-1] == len(new) or len(new) == 1:
np.putmask(new_values, mask, new)
else:
raise ValueError("cannot assign mismatch length to masked array")
else:
np.putmask(new_values, mask, new)
# maybe upcast me
elif mask.any():
if transpose:
mask = mask.T
if isinstance(new, np.ndarray):
new = new.T
axis = new_values.ndim - axis - 1
# Pseudo-broadcast
if getattr(new, "ndim", 0) >= 1:
if self.ndim - 1 == new.ndim:
new_shape = list(new.shape)
new_shape.insert(axis, 1)
new = new.reshape(tuple(new_shape))
# operate column-by-column
def f(mask, val, idx):
if idx is None:
# ndim==1 case.
n = new
else:
if isinstance(new, np.ndarray):
n = np.squeeze(new[idx % new.shape[0]])
else:
n = np.array(new)
# type of the new block
dtype, _ = maybe_promote(n.dtype)
# we need to explicitly astype here to make a copy
n = n.astype(dtype)
nv = _putmask_smart(val, mask, n)
return nv
new_blocks = self.split_and_operate(mask, f, inplace)
return new_blocks
if inplace:
return [self]
if transpose:
new_values = new_values.T
return [self.make_block(new_values)]
def coerce_to_target_dtype(self, other):
"""
coerce the current block to a dtype compat for other
we will return a block, possibly object, and not raise
we can also safely try to coerce to the same dtype
and will receive the same block
"""
# if we cannot then coerce to object
dtype, _ = infer_dtype_from(other, pandas_dtype=True)
if is_dtype_equal(self.dtype, dtype):
return self
if self.is_bool or is_object_dtype(dtype) or is_bool_dtype(dtype):
# we don't upcast to bool
return self.astype(object)
elif (self.is_float or self.is_complex) and (
is_integer_dtype(dtype) or is_float_dtype(dtype)
):
# don't coerce float/complex to int
return self
elif (
self.is_datetime
or is_datetime64_dtype(dtype)
or is_datetime64tz_dtype(dtype)
):
# not a datetime
if not (
(is_datetime64_dtype(dtype) or is_datetime64tz_dtype(dtype))
and self.is_datetime
):
return self.astype(object)
# don't upcast timezone with different timezone or no timezone
mytz = getattr(self.dtype, "tz", None)
othertz = getattr(dtype, "tz", None)
if not tz_compare(mytz, othertz):
return self.astype(object)
raise AssertionError(
f"possible recursion in coerce_to_target_dtype: {self} {other}"
)
elif self.is_timedelta or is_timedelta64_dtype(dtype):
# not a timedelta
if not (is_timedelta64_dtype(dtype) and self.is_timedelta):
return self.astype(object)
raise AssertionError(
f"possible recursion in coerce_to_target_dtype: {self} {other}"
)
try:
return self.astype(dtype)
except (ValueError, TypeError, OverflowError):
return self.astype(object)
def interpolate(
self,
method="pad",
axis=0,
index=None,
values=None,
inplace=False,
limit=None,
limit_direction="forward",
limit_area=None,
fill_value=None,
coerce=False,
downcast=None,
**kwargs,
):
inplace = validate_bool_kwarg(inplace, "inplace")
def check_int_bool(self, inplace):
# Only FloatBlocks will contain NaNs.
# timedelta subclasses IntBlock
if (self.is_bool or self.is_integer) and not self.is_timedelta:
if inplace:
return self
else:
return self.copy()
# a fill na type method
try:
m = missing.clean_fill_method(method)
except ValueError:
m = None
if m is not None:
r = check_int_bool(self, inplace)
if r is not None:
return r
return self._interpolate_with_fill(
method=m,
axis=axis,
inplace=inplace,
limit=limit,
fill_value=fill_value,
coerce=coerce,
downcast=downcast,
)
# validate the interp method
m = missing.clean_interp_method(method, **kwargs)
r = check_int_bool(self, inplace)
if r is not None:
return r
return self._interpolate(
method=m,
index=index,
values=values,
axis=axis,
limit=limit,
limit_direction=limit_direction,
limit_area=limit_area,
fill_value=fill_value,
inplace=inplace,
downcast=downcast,
**kwargs,
)
def _interpolate_with_fill(
self,
method="pad",
axis=0,
inplace=False,
limit=None,
fill_value=None,
coerce=False,
downcast=None,
):
""" fillna but using the interpolate machinery """
inplace = validate_bool_kwarg(inplace, "inplace")
# if we are coercing, then don't force the conversion
# if the block can't hold the type
if coerce:
if not self._can_hold_na:
if inplace:
return [self]
else:
return [self.copy()]
values = self.values if inplace else self.values.copy()
# We only get here for non-ExtensionBlock
fill_value = convert_scalar(self.values, fill_value)
values = missing.interpolate_2d(
values,
method=method,
axis=axis,
limit=limit,
fill_value=fill_value,
dtype=self.dtype,
)
blocks = [self.make_block_same_class(values, ndim=self.ndim)]
return self._maybe_downcast(blocks, downcast)
def _interpolate(
self,
method=None,
index=None,
values=None,
fill_value=None,
axis=0,
limit=None,
limit_direction="forward",
limit_area=None,
inplace=False,
downcast=None,
**kwargs,
):
""" interpolate using scipy wrappers """
inplace = validate_bool_kwarg(inplace, "inplace")
data = self.values if inplace else self.values.copy()
# only deal with floats
if not self.is_float:
if not self.is_integer:
return self
data = data.astype(np.float64)
if fill_value is None:
fill_value = self.fill_value
if method in ("krogh", "piecewise_polynomial", "pchip"):
if not index.is_monotonic:
raise ValueError(
f"{method} interpolation requires that the index be monotonic."
)
# process 1-d slices in the axis direction
def func(x):
# process a 1-d slice, returning it
# should the axis argument be handled below in apply_along_axis?
# i.e. not an arg to missing.interpolate_1d
return missing.interpolate_1d(
index,
x,
method=method,
limit=limit,
limit_direction=limit_direction,
limit_area=limit_area,
fill_value=fill_value,
bounds_error=False,
**kwargs,
)
# interp each column independently
interp_values = np.apply_along_axis(func, axis, data)
blocks = [self.make_block_same_class(interp_values)]
return self._maybe_downcast(blocks, downcast)
def take_nd(self, indexer, axis, new_mgr_locs=None, fill_tuple=None):
"""
Take values according to indexer and return them as a block.bb
"""
# algos.take_nd dispatches for DatetimeTZBlock, CategoricalBlock
# so need to preserve types
# sparse is treated like an ndarray, but needs .get_values() shaping
values = self.values
if fill_tuple is None:
fill_value = self.fill_value
allow_fill = False
else:
fill_value = fill_tuple[0]
allow_fill = True
new_values = algos.take_nd(
values, indexer, axis=axis, allow_fill=allow_fill, fill_value=fill_value
)
# Called from three places in managers, all of which satisfy
# this assertion
assert not (axis == 0 and new_mgr_locs is None)
if new_mgr_locs is None:
new_mgr_locs = self.mgr_locs
if not is_dtype_equal(new_values.dtype, self.dtype):
return self.make_block(new_values, new_mgr_locs)
else:
return self.make_block_same_class(new_values, new_mgr_locs)
def diff(self, n: int, axis: int = 1) -> List["Block"]:
""" return block for the diff of the values """
new_values = algos.diff(self.values, n, axis=axis, stacklevel=7)
# We use block_shape for ExtensionBlock subclasses, which may call here
# via a super.
new_values = _block_shape(new_values, ndim=self.ndim)
return [self.make_block(values=new_values)]
def shift(self, periods, axis=0, fill_value=None):
""" shift the block by periods, possibly upcast """
# convert integer to float if necessary. need to do a lot more than
# that, handle boolean etc also
new_values, fill_value = maybe_upcast(self.values, fill_value)
# make sure array sent to np.roll is c_contiguous
f_ordered = new_values.flags.f_contiguous
if f_ordered:
new_values = new_values.T
axis = new_values.ndim - axis - 1
if np.prod(new_values.shape):
new_values = np.roll(new_values, ensure_platform_int(periods), axis=axis)
axis_indexer = [slice(None)] * self.ndim
if periods > 0:
axis_indexer[axis] = slice(None, periods)
else:
axis_indexer[axis] = slice(periods, None)
new_values[tuple(axis_indexer)] = fill_value
# restore original order
if f_ordered:
new_values = new_values.T
return [self.make_block(new_values)]
def where(
self,
other,
cond,
align=True,
errors="raise",
try_cast: bool = False,
axis: int = 0,
) -> List["Block"]:
"""
evaluate the block; return result block(s) from the result
Parameters
----------
other : a ndarray/object
cond : the condition to respect
align : boolean, perform alignment on other/cond
errors : str, {'raise', 'ignore'}, default 'raise'
- ``raise`` : allow exceptions to be raised
- ``ignore`` : suppress exceptions. On error return original object
axis : int
Returns
-------
a new block(s), the result of the func
"""
import pandas.core.computation.expressions as expressions
assert errors in ["raise", "ignore"]
transpose = self.ndim == 2
values = self.values
orig_other = other
if transpose:
values = values.T
other = getattr(other, "_values", getattr(other, "values", other))
cond = getattr(cond, "values", cond)
# If the default broadcasting would go in the wrong direction, then
# explicitly reshape other instead
if getattr(other, "ndim", 0) >= 1:
if values.ndim - 1 == other.ndim and axis == 1:
other = other.reshape(tuple(other.shape + (1,)))
elif transpose and values.ndim == self.ndim - 1:
cond = cond.T
if not hasattr(cond, "shape"):
raise ValueError("where must have a condition that is ndarray like")
def where_func(cond, values, other):
if not (
(self.is_integer or self.is_bool)
and lib.is_float(other)
and np.isnan(other)
):
# np.where will cast integer array to floats in this case
if not self._can_hold_element(other):
raise TypeError
if lib.is_scalar(other) and isinstance(values, np.ndarray):
# convert datetime to datetime64, timedelta to timedelta64
other = convert_scalar(values, other)
# By the time we get here, we should have all Series/Index
# args extracted to ndarray
fastres = expressions.where(cond, values, other)
return fastres
if cond.ravel().all():
result = values
else:
# see if we can operate on the entire block, or need item-by-item
# or if we are a single block (ndim == 1)
try:
result = where_func(cond, values, other)
except TypeError:
# we cannot coerce, return a compat dtype
# we are explicitly ignoring errors
block = self.coerce_to_target_dtype(other)
blocks = block.where(
orig_other,
cond,
align=align,
errors=errors,
try_cast=try_cast,
axis=axis,
)
return self._maybe_downcast(blocks, "infer")
if self._can_hold_na or self.ndim == 1:
if transpose:
result = result.T
return [self.make_block(result)]
# might need to separate out blocks
axis = cond.ndim - 1
cond = cond.swapaxes(axis, 0)
mask = np.array([cond[i].all() for i in range(cond.shape[0])], dtype=bool)
result_blocks = []
for m in [mask, ~mask]:
if m.any():
taken = result.take(m.nonzero()[0], axis=axis)
r = maybe_downcast_numeric(taken, self.dtype)
nb = self.make_block(r.T, placement=self.mgr_locs[m])
result_blocks.append(nb)
return result_blocks
def equals(self, other) -> bool:
if self.dtype != other.dtype or self.shape != other.shape:
return False
return array_equivalent(self.values, other.values)
def _unstack(self, unstacker_func, new_columns, n_rows, fill_value):
"""Return a list of unstacked blocks of self
Parameters
----------
unstacker_func : callable
Partially applied unstacker.
new_columns : Index
All columns of the unstacked BlockManager.
n_rows : int
Only used in ExtensionBlock._unstack
fill_value : int
Only used in ExtensionBlock._unstack
Returns
-------
blocks : list of Block
New blocks of unstacked values.
mask : array_like of bool
The mask of columns of `blocks` we should keep.
"""
unstacker = unstacker_func(self.values.T)
new_items = unstacker.get_new_columns()
new_placement = new_columns.get_indexer(new_items)
new_values, mask = unstacker.get_new_values()
mask = mask.any(0)
new_values = new_values.T[mask]
new_placement = new_placement[mask]
blocks = [make_block(new_values, placement=new_placement)]
return blocks, mask
def quantile(self, qs, interpolation="linear", axis=0):
"""
compute the quantiles of the
Parameters
----------
qs: a scalar or list of the quantiles to be computed
interpolation: type of interpolation, default 'linear'
axis: axis to compute, default 0
Returns
-------
Block
"""
# We should always have ndim == 2 because Series dispatches to DataFrame
assert self.ndim == 2
values = self.get_values()
is_empty = values.shape[axis] == 0
orig_scalar = not is_list_like(qs)
if orig_scalar:
# make list-like, unpack later
qs = [qs]
if is_empty:
# create the array of na_values
# 2d len(values) * len(qs)
result = np.repeat(
np.array([self.fill_value] * len(qs)), len(values)
).reshape(len(values), len(qs))
else:
# asarray needed for Sparse, see GH#24600
mask = np.asarray(isna(values))
result = nanpercentile(
values,
np.array(qs) * 100,
axis=axis,
na_value=self.fill_value,
mask=mask,
ndim=values.ndim,
interpolation=interpolation,
)
result = np.array(result, copy=False)
result = result.T
if orig_scalar and not lib.is_scalar(result):
# result could be scalar in case with is_empty and self.ndim == 1
assert result.shape[-1] == 1, result.shape
result = result[..., 0]
result = lib.item_from_zerodim(result)
ndim = np.ndim(result)
return make_block(result, placement=np.arange(len(result)), ndim=ndim)
def _replace_coerce(
self, to_replace, value, inplace=True, regex=False, convert=False, mask=None
):
"""
Replace value corresponding to the given boolean array with another
value.
Parameters
----------
to_replace : object or pattern
Scalar to replace or regular expression to match.
value : object
Replacement object.
inplace : bool, default False
Perform inplace modification.
regex : bool, default False
If true, perform regular expression substitution.
convert : bool, default True
If true, try to coerce any object types to better types.
mask : array-like of bool, optional
True indicate corresponding element is ignored.
Returns
-------
A new block if there is anything to replace or the original block.
"""
if mask.any():
if not regex:
self = self.coerce_to_target_dtype(value)
return self.putmask(mask, value, inplace=inplace)
else:
return self._replace_single(
to_replace,
value,
inplace=inplace,
regex=regex,
convert=convert,
mask=mask,
)
return self
class NonConsolidatableMixIn:
""" hold methods for the nonconsolidatable blocks """
_can_consolidate = False
_verify_integrity = False
_validate_ndim = False
def __init__(self, values, placement, ndim=None):
"""Initialize a non-consolidatable block.
'ndim' may be inferred from 'placement'.
This will call continue to call __init__ for the other base
classes mixed in with this Mixin.
"""
# Placement must be converted to BlockPlacement so that we can check
# its length
if not isinstance(placement, libinternals.BlockPlacement):
placement = libinternals.BlockPlacement(placement)
# Maybe infer ndim from placement
if ndim is None:
if len(placement) != 1:
ndim = 1
else:
ndim = 2
super().__init__(values, placement, ndim=ndim)
@property
def shape(self):
if self.ndim == 1:
return ((len(self.values)),)
return (len(self.mgr_locs), len(self.values))
def iget(self, col):
if self.ndim == 2 and isinstance(col, tuple):
col, loc = col
if not com.is_null_slice(col) and col != 0:
raise IndexError(f"{self} only contains one item")
elif isinstance(col, slice):
if col != slice(None):
raise NotImplementedError(col)
return self.values[[loc]]
return self.values[loc]
else:
if col != 0:
raise IndexError(f"{self} only contains one item")
return self.values
def should_store(self, value):
return isinstance(value, self._holder)
def set(self, locs, values, check=False):
assert locs.tolist() == [0]
self.values = values
def putmask(self, mask, new, align=True, inplace=False, axis=0, transpose=False):
"""
putmask the data to the block; we must be a single block and not
generate other blocks
return the resulting block
Parameters
----------
mask : the condition to respect
new : a ndarray/object
align : boolean, perform alignment on other/cond, default is True
inplace : perform inplace modification, default is False
Returns
-------
a new block, the result of the putmask
"""
inplace = validate_bool_kwarg(inplace, "inplace")
# use block's copy logic.
# .values may be an Index which does shallow copy by default
new_values = self.values if inplace else self.copy().values
if isinstance(new, np.ndarray) and len(new) == len(mask):
new = new[mask]
mask = _safe_reshape(mask, new_values.shape)
new_values[mask] = new
return [self.make_block(values=new_values)]
def _get_unstack_items(self, unstacker, new_columns):
"""
Get the placement, values, and mask for a Block unstack.
This is shared between ObjectBlock and ExtensionBlock. They
differ in that ObjectBlock passes the values, while ExtensionBlock
passes the dummy ndarray of positions to be used by a take
later.
Parameters
----------
unstacker : pandas.core.reshape.reshape._Unstacker
new_columns : Index
All columns of the unstacked BlockManager.
Returns
-------
new_placement : ndarray[int]
The placement of the new columns in `new_columns`.
new_values : Union[ndarray, ExtensionArray]
The first return value from _Unstacker.get_new_values.
mask : ndarray[bool]
The second return value from _Unstacker.get_new_values.
"""
# shared with ExtensionBlock
new_items = unstacker.get_new_columns()
new_placement = new_columns.get_indexer(new_items)
new_values, mask = unstacker.get_new_values()
mask = mask.any(0)
return new_placement, new_values, mask
class ExtensionBlock(NonConsolidatableMixIn, Block):
"""Block for holding extension types.
Notes
-----
This holds all 3rd-party extension array types. It's also the immediate
parent class for our internal extension types' blocks, CategoricalBlock.
ExtensionArrays are limited to 1-D.
"""
is_extension = True
def __init__(self, values, placement, ndim=None):
values = self._maybe_coerce_values(values)
super().__init__(values, placement, ndim)
def _maybe_coerce_values(self, values):
"""
Unbox to an extension array.
This will unbox an ExtensionArray stored in an Index or Series.
ExtensionArrays pass through. No dtype coercion is done.
Parameters
----------
values : Index, Series, ExtensionArray
Returns
-------
ExtensionArray
"""
return extract_array(values)
@property
def _holder(self):
# For extension blocks, the holder is values-dependent.
return type(self.values)
@property
def fill_value(self):
# Used in reindex_indexer
return self.values.dtype.na_value
@property
def _can_hold_na(self):
# The default ExtensionArray._can_hold_na is True
return self._holder._can_hold_na
@property
def is_view(self):
"""Extension arrays are never treated as views."""
return False
@property
def is_numeric(self):
return self.values.dtype._is_numeric
def setitem(self, indexer, value):
"""Set the value inplace, returning a same-typed block.
This differs from Block.setitem by not allowing setitem to change
the dtype of the Block.
Parameters
----------
indexer : tuple, list-like, array-like, slice
The subset of self.values to set
value : object
The value being set
Returns
-------
Block
Notes
-----
`indexer` is a direct slice/positional indexer. `value` must
be a compatible shape.
"""
if isinstance(indexer, tuple):
# we are always 1-D
indexer = indexer[0]
check_setitem_lengths(indexer, value, self.values)
self.values[indexer] = value
return self
def get_values(self, dtype=None):
# ExtensionArrays must be iterable, so this works.
values = np.asarray(self.values)
if values.ndim == self.ndim - 1:
values = values.reshape((1,) + values.shape)
return values
def array_values(self) -> ExtensionArray:
return self.values
def to_dense(self):
return np.asarray(self.values)
def to_native_types(self, slicer=None, na_rep="nan", quoting=None, **kwargs):
"""override to use ExtensionArray astype for the conversion"""
values = self.values
if slicer is not None:
values = values[slicer]
mask = isna(values)
values = np.asarray(values.astype(object))
values[mask] = na_rep
# we are expected to return a 2-d ndarray
return values.reshape(1, len(values))
def take_nd(self, indexer, axis=0, new_mgr_locs=None, fill_tuple=None):
"""
Take values according to indexer and return them as a block.
"""
if fill_tuple is None:
fill_value = None
else:
fill_value = fill_tuple[0]
# axis doesn't matter; we are really a single-dim object
# but are passed the axis depending on the calling routing
# if its REALLY axis 0, then this will be a reindex and not a take
new_values = self.values.take(indexer, fill_value=fill_value, allow_fill=True)
# Called from three places in managers, all of which satisfy
# this assertion
assert not (self.ndim == 1 and new_mgr_locs is None)
if new_mgr_locs is None:
new_mgr_locs = self.mgr_locs
return self.make_block_same_class(new_values, new_mgr_locs)
def _can_hold_element(self, element: Any) -> bool:
# XXX: We may need to think about pushing this onto the array.
# We're doing the same as CategoricalBlock here.
return True
def _slice(self, slicer):
""" return a slice of my values """
# slice the category
# return same dims as we currently have
if isinstance(slicer, tuple) and len(slicer) == 2:
if not com.is_null_slice(slicer[0]):
raise AssertionError("invalid slicing for a 1-ndim categorical")
slicer = slicer[1]
return self.values[slicer]
def concat_same_type(self, to_concat, placement=None):
"""
Concatenate list of single blocks of the same type.
"""
values = self._holder._concat_same_type([blk.values for blk in to_concat])
placement = placement or slice(0, len(values), 1)
return self.make_block_same_class(values, ndim=self.ndim, placement=placement)
def fillna(self, value, limit=None, inplace=False, downcast=None):
values = self.values if inplace else self.values.copy()
values = values.fillna(value=value, limit=limit)
return [
self.make_block_same_class(
values=values, placement=self.mgr_locs, ndim=self.ndim
)
]
def interpolate(
self, method="pad", axis=0, inplace=False, limit=None, fill_value=None, **kwargs
):
values = self.values if inplace else self.values.copy()
return self.make_block_same_class(
values=values.fillna(value=fill_value, method=method, limit=limit),
placement=self.mgr_locs,
)
def diff(self, n: int, axis: int = 1) -> List["Block"]:
if axis == 1:
# we are by definition 1D.
axis = 0
return super().diff(n, axis)
def shift(
self,
periods: int,
axis: libinternals.BlockPlacement = 0,
fill_value: Any = None,
) -> List["ExtensionBlock"]:
"""
Shift the block by `periods`.
Dispatches to underlying ExtensionArray and re-boxes in an
ExtensionBlock.
"""
return [
self.make_block_same_class(
self.values.shift(periods=periods, fill_value=fill_value),
placement=self.mgr_locs,
ndim=self.ndim,
)
]
def where(
self,
other,
cond,
align=True,
errors="raise",
try_cast: bool = False,
axis: int = 0,
) -> List["Block"]:
if isinstance(other, ABCDataFrame):
# ExtensionArrays are 1-D, so if we get here then
# `other` should be a DataFrame with a single column.
assert other.shape[1] == 1
other = other.iloc[:, 0]
other = extract_array(other, extract_numpy=True)
if isinstance(cond, ABCDataFrame):
assert cond.shape[1] == 1
cond = cond.iloc[:, 0]
cond = extract_array(cond, extract_numpy=True)
if lib.is_scalar(other) and isna(other):
# The default `other` for Series / Frame is np.nan
# we want to replace that with the correct NA value
# for the type
other = self.dtype.na_value
if is_sparse(self.values):
# TODO(SparseArray.__setitem__): remove this if condition
# We need to re-infer the type of the data after doing the
# where, for cases where the subtypes don't match
dtype = None
else:
dtype = self.dtype
result = self.values.copy()
icond = ~cond
if lib.is_scalar(other):
set_other = other
else:
set_other = other[icond]
try:
result[icond] = set_other
except (NotImplementedError, TypeError):
# NotImplementedError for class not implementing `__setitem__`
# TypeError for SparseArray, which implements just to raise
# a TypeError
result = self._holder._from_sequence(
np.where(cond, self.values, other), dtype=dtype
)
return [self.make_block_same_class(result, placement=self.mgr_locs)]
@property
def _ftype(self):
return getattr(self.values, "_pandas_ftype", Block._ftype)
def _unstack(self, unstacker_func, new_columns, n_rows, fill_value):
# ExtensionArray-safe unstack.
# We override ObjectBlock._unstack, which unstacks directly on the
# values of the array. For EA-backed blocks, this would require
# converting to a 2-D ndarray of objects.
# Instead, we unstack an ndarray of integer positions, followed by
# a `take` on the actual values.
dummy_arr = np.arange(n_rows)
dummy_unstacker = functools.partial(unstacker_func, fill_value=-1)
unstacker = dummy_unstacker(dummy_arr)
new_placement, new_values, mask = self._get_unstack_items(
unstacker, new_columns
)
blocks = [
self.make_block_same_class(
self.values.take(indices, allow_fill=True, fill_value=fill_value),
[place],
)
for indices, place in zip(new_values.T, new_placement)
]
return blocks, mask
class ObjectValuesExtensionBlock(ExtensionBlock):
"""
Block providing backwards-compatibility for `.values`.
Used by PeriodArray and IntervalArray to ensure that
Series[T].values is an ndarray of objects.
"""
def external_values(self):
return self.values.astype(object)
class NumericBlock(Block):
__slots__ = ()
is_numeric = True
_can_hold_na = True
class FloatOrComplexBlock(NumericBlock):
__slots__ = ()
def equals(self, other) -> bool:
if self.dtype != other.dtype or self.shape != other.shape:
return False
left, right = self.values, other.values
return ((left == right) | (np.isnan(left) & np.isnan(right))).all()
class FloatBlock(FloatOrComplexBlock):
__slots__ = ()
is_float = True
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return issubclass(tipo.type, (np.floating, np.integer)) and not issubclass(
tipo.type, (np.datetime64, np.timedelta64)
)
return isinstance(
element, (float, int, np.floating, np.int_)
) and not isinstance(
element,
(bool, np.bool_, datetime, timedelta, np.datetime64, np.timedelta64),
)
def to_native_types(
self,
slicer=None,
na_rep="",
float_format=None,
decimal=".",
quoting=None,
**kwargs,
):
""" convert to our native types format, slicing if desired """
values = self.values
if slicer is not None:
values = values[:, slicer]
# see gh-13418: no special formatting is desired at the
# output (important for appropriate 'quoting' behaviour),
# so do not pass it through the FloatArrayFormatter
if float_format is None and decimal == ".":
mask = isna(values)
if not quoting:
values = values.astype(str)
else:
values = np.array(values, dtype="object")
values[mask] = na_rep
return values
from pandas.io.formats.format import FloatArrayFormatter
formatter = FloatArrayFormatter(
values,
na_rep=na_rep,
float_format=float_format,
decimal=decimal,
quoting=quoting,
fixed_width=False,
)
return formatter.get_result_as_array()
def should_store(self, value):
# when inserting a column should not coerce integers to floats
# unnecessarily
return issubclass(value.dtype.type, np.floating) and value.dtype == self.dtype
class ComplexBlock(FloatOrComplexBlock):
__slots__ = ()
is_complex = True
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return issubclass(tipo.type, (np.floating, np.integer, np.complexfloating))
return isinstance(
element, (float, int, complex, np.float_, np.int_)
) and not isinstance(element, (bool, np.bool_))
def should_store(self, value):
return issubclass(value.dtype.type, np.complexfloating)
class IntBlock(NumericBlock):
__slots__ = ()
is_integer = True
_can_hold_na = False
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return (
issubclass(tipo.type, np.integer)
and not issubclass(tipo.type, (np.datetime64, np.timedelta64))
and self.dtype.itemsize >= tipo.itemsize
)
return is_integer(element)
def should_store(self, value):
return is_integer_dtype(value) and value.dtype == self.dtype
class DatetimeLikeBlockMixin:
"""Mixin class for DatetimeBlock, DatetimeTZBlock, and TimedeltaBlock."""
@property
def _holder(self):
return DatetimeArray
@property
def fill_value(self):
return np.datetime64("NaT", "ns")
def get_values(self, dtype=None):
"""
return object dtype as boxed values, such as Timestamps/Timedelta
"""
if is_object_dtype(dtype):
values = self.values.ravel()
result = self._holder(values).astype(object)
return result.reshape(self.values.shape)
return self.values
def internal_values(self):
# Override to return DatetimeArray and TimedeltaArray
return self.array_values()
class DatetimeBlock(DatetimeLikeBlockMixin, Block):
__slots__ = ()
is_datetime = True
def __init__(self, values, placement, ndim=None):
values = self._maybe_coerce_values(values)
super().__init__(values, placement=placement, ndim=ndim)
@property
def _can_hold_na(self):
return True
def _maybe_coerce_values(self, values):
"""
Input validation for values passed to __init__. Ensure that
we have datetime64ns, coercing if necessary.
Parameters
----------
values : array-like
Must be convertible to datetime64
Returns
-------
values : ndarray[datetime64ns]
Overridden by DatetimeTZBlock.
"""
if values.dtype != _NS_DTYPE:
values = conversion.ensure_datetime64ns(values)
if isinstance(values, DatetimeArray):
values = values._data
assert isinstance(values, np.ndarray), type(values)
return values
def astype(self, dtype, copy: bool = False, errors: str = "raise"):
"""
these automatically copy, so copy=True has no effect
raise on an except if raise == True
"""
dtype = pandas_dtype(dtype)
# if we are passed a datetime64[ns, tz]
if is_datetime64tz_dtype(dtype):
values = self.values
if getattr(values, "tz", None) is None:
values = DatetimeArray(values).tz_localize("UTC")
values = values.tz_convert(dtype.tz)
return self.make_block(values)
# delegate
return super().astype(dtype=dtype, copy=copy, errors=errors)
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
if self.is_datetimetz:
# require exact match, since non-nano does not exist
return is_dtype_equal(tipo, self.dtype) or is_valid_nat_for_dtype(
element, self.dtype
)
# GH#27419 if we get a non-nano datetime64 object
return is_datetime64_dtype(tipo)
elif element is NaT:
return True
elif isinstance(element, datetime):
if self.is_datetimetz:
return tz_compare(element.tzinfo, self.dtype.tz)
return element.tzinfo is None
return is_valid_nat_for_dtype(element, self.dtype)
def to_native_types(
self, slicer=None, na_rep=None, date_format=None, quoting=None, **kwargs
):
""" convert to our native types format, slicing if desired """
values = self.values
i8values = self.values.view("i8")
if slicer is not None:
values = values[..., slicer]
i8values = i8values[..., slicer]
from pandas.io.formats.format import _get_format_datetime64_from_values
fmt = _get_format_datetime64_from_values(values, date_format)
result = tslib.format_array_from_datetime(
i8values.ravel(),
tz=getattr(self.values, "tz", None),
format=fmt,
na_rep=na_rep,
).reshape(i8values.shape)
return np.atleast_2d(result)
def should_store(self, value):
return (
issubclass(value.dtype.type, np.datetime64)
and not is_datetime64tz_dtype(value)
and not is_extension_array_dtype(value)
)
def set(self, locs, values):
"""
Modify Block in-place with new item value
Returns
-------
None
"""
values = conversion.ensure_datetime64ns(values, copy=False)
self.values[locs] = values
def external_values(self):
return np.asarray(self.values.astype("datetime64[ns]", copy=False))
def array_values(self) -> ExtensionArray:
return DatetimeArray._simple_new(self.values)
class DatetimeTZBlock(ExtensionBlock, DatetimeBlock):
""" implement a datetime64 block with a tz attribute """
__slots__ = ()
is_datetimetz = True
is_extension = True
internal_values = Block.internal_values
_can_hold_element = DatetimeBlock._can_hold_element
to_native_types = DatetimeBlock.to_native_types
fill_value = np.datetime64("NaT", "ns")
@property
def _holder(self):
return DatetimeArray
def _maybe_coerce_values(self, values):
"""Input validation for values passed to __init__. Ensure that
we have datetime64TZ, coercing if necessary.
Parameters
----------
values : array-like
Must be convertible to datetime64
Returns
-------
values : DatetimeArray
"""
if not isinstance(values, self._holder):
values = self._holder(values)
if values.tz is None:
raise ValueError("cannot create a DatetimeTZBlock without a tz")
return values
@property
def is_view(self):
""" return a boolean if I am possibly a view """
# check the ndarray values of the DatetimeIndex values
return self.values._data.base is not None
def get_values(self, dtype=None):
"""
Returns an ndarray of values.
Parameters
----------
dtype : np.dtype
Only `object`-like dtypes are respected here (not sure
why).
Returns
-------
values : ndarray
When ``dtype=object``, then and object-dtype ndarray of
boxed values is returned. Otherwise, an M8[ns] ndarray
is returned.
DatetimeArray is always 1-d. ``get_values`` will reshape
the return value to be the same dimensionality as the
block.
"""
values = self.values
if is_object_dtype(dtype):
values = values.astype(object)
values = np.asarray(values)
if self.ndim == 2:
# Ensure that our shape is correct for DataFrame.
# ExtensionArrays are always 1-D, even in a DataFrame when
# the analogous NumPy-backed column would be a 2-D ndarray.
values = values.reshape(1, -1)
return values
def to_dense(self):
# we request M8[ns] dtype here, even though it discards tzinfo,
# as lots of code (e.g. anything using values_from_object)
# expects that behavior.
return np.asarray(self.values, dtype=_NS_DTYPE)
def _slice(self, slicer):
""" return a slice of my values """
if isinstance(slicer, tuple):
col, loc = slicer
if not com.is_null_slice(col) and col != 0:
raise IndexError(f"{self} only contains one item")
return self.values[loc]
return self.values[slicer]
def diff(self, n: int, axis: int = 0) -> List["Block"]:
"""
1st discrete difference.
Parameters
----------
n : int
Number of periods to diff.
axis : int, default 0
Axis to diff upon.
Returns
-------
A list with a new TimeDeltaBlock.
Notes
-----
The arguments here are mimicking shift so they are called correctly
by apply.
"""
if axis == 0:
# Cannot currently calculate diff across multiple blocks since this
# function is invoked via apply
raise NotImplementedError
new_values = (self.values - self.shift(n, axis=axis)[0].values).asi8
# Reshape the new_values like how algos.diff does for timedelta data
new_values = new_values.reshape(1, len(new_values))
new_values = new_values.astype("timedelta64[ns]")
return [TimeDeltaBlock(new_values, placement=self.mgr_locs.indexer)]
def concat_same_type(self, to_concat, placement=None):
# need to handle concat([tz1, tz2]) here, since DatetimeArray
# only handles cases where all the tzs are the same.
# Instead of placing the condition here, it could also go into the
# is_uniform_join_units check, but I'm not sure what is better.
if len({x.dtype for x in to_concat}) > 1:
values = concat_datetime([x.values for x in to_concat])
placement = placement or slice(0, len(values), 1)
if self.ndim > 1:
values = np.atleast_2d(values)
return ObjectBlock(values, ndim=self.ndim, placement=placement)
return super().concat_same_type(to_concat, placement)
def fillna(self, value, limit=None, inplace=False, downcast=None):
# We support filling a DatetimeTZ with a `value` whose timezone
# is different by coercing to object.
if self._can_hold_element(value):
return super().fillna(value, limit, inplace, downcast)
# different timezones, or a non-tz
return self.astype(object).fillna(
value, limit=limit, inplace=inplace, downcast=downcast
)
def setitem(self, indexer, value):
# https://github.com/pandas-dev/pandas/issues/24020
# Need a dedicated setitem until #24020 (type promotion in setitem
# for extension arrays) is designed and implemented.
if self._can_hold_element(value) or (
isinstance(indexer, np.ndarray) and indexer.size == 0
):
return super().setitem(indexer, value)
obj_vals = self.values.astype(object)
newb = make_block(
obj_vals, placement=self.mgr_locs, klass=ObjectBlock, ndim=self.ndim
)
return newb.setitem(indexer, value)
def equals(self, other) -> bool:
# override for significant performance improvement
if self.dtype != other.dtype or self.shape != other.shape:
return False
return (self.values.view("i8") == other.values.view("i8")).all()
def quantile(self, qs, interpolation="linear", axis=0):
naive = self.values.view("M8[ns]")
# kludge for 2D block with 1D values
naive = naive.reshape(self.shape)
blk = self.make_block(naive)
res_blk = blk.quantile(qs, interpolation=interpolation, axis=axis)
# ravel is kludge for 2D block with 1D values, assumes column-like
aware = self._holder(res_blk.values.ravel(), dtype=self.dtype)
return self.make_block_same_class(aware, ndim=res_blk.ndim)
class TimeDeltaBlock(DatetimeLikeBlockMixin, IntBlock):
__slots__ = ()
is_timedelta = True
_can_hold_na = True
is_numeric = False
fill_value = np.timedelta64("NaT", "ns")
def __init__(self, values, placement, ndim=None):
if values.dtype != _TD_DTYPE:
values = conversion.ensure_timedelta64ns(values)
if isinstance(values, TimedeltaArray):
values = values._data
assert isinstance(values, np.ndarray), type(values)
super().__init__(values, placement=placement, ndim=ndim)
@property
def _holder(self):
return TimedeltaArray
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return issubclass(tipo.type, np.timedelta64)
elif element is NaT:
return True
elif isinstance(element, (timedelta, np.timedelta64)):
return True
return is_valid_nat_for_dtype(element, self.dtype)
def fillna(self, value, **kwargs):
# allow filling with integers to be
# interpreted as nanoseconds
if is_integer(value):
# Deprecation GH#24694, GH#19233
raise TypeError(
"Passing integers to fillna for timedelta64[ns] dtype is no "
"longer supported. To obtain the old behavior, pass "
"`pd.Timedelta(seconds=n)` instead."
)
return super().fillna(value, **kwargs)
def should_store(self, value):
return issubclass(
value.dtype.type, np.timedelta64
) and not is_extension_array_dtype(value)
def to_native_types(self, slicer=None, na_rep=None, quoting=None, **kwargs):
""" convert to our native types format, slicing if desired """
values = self.values
if slicer is not None:
values = values[:, slicer]
mask = isna(values)
rvalues = np.empty(values.shape, dtype=object)
if na_rep is None:
na_rep = "NaT"
rvalues[mask] = na_rep
imask = (~mask).ravel()
# FIXME:
# should use the formats.format.Timedelta64Formatter here
# to figure what format to pass to the Timedelta
# e.g. to not show the decimals say
rvalues.flat[imask] = np.array(
[Timedelta(val)._repr_base(format="all") for val in values.ravel()[imask]],
dtype=object,
)
return rvalues
def external_values(self):
return np.asarray(self.values.astype("timedelta64[ns]", copy=False))
def array_values(self) -> ExtensionArray:
return TimedeltaArray._simple_new(self.values)
class BoolBlock(NumericBlock):
__slots__ = ()
is_bool = True
_can_hold_na = False
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return issubclass(tipo.type, np.bool_)
return isinstance(element, (bool, np.bool_))
def should_store(self, value):
return issubclass(value.dtype.type, np.bool_) and not is_extension_array_dtype(
value
)
def replace(
self, to_replace, value, inplace=False, filter=None, regex=False, convert=True
):
inplace = validate_bool_kwarg(inplace, "inplace")
to_replace_values = np.atleast_1d(to_replace)
if not np.can_cast(to_replace_values, bool):
return self
return super().replace(
to_replace,
value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
class ObjectBlock(Block):
__slots__ = ()
is_object = True
_can_hold_na = True
def __init__(self, values, placement=None, ndim=2):
if issubclass(values.dtype.type, str):
values = np.array(values, dtype=object)
super().__init__(values, ndim=ndim, placement=placement)
@property
def is_bool(self):
""" we can be a bool if we have only bool values but are of type
object
"""
return lib.is_bool_array(self.values.ravel())
def convert(
self,
copy: bool = True,
datetime: bool = True,
numeric: bool = True,
timedelta: bool = True,
coerce: bool = False,
):
""" attempt to coerce any object types to better types return a copy of
the block (if copy = True) by definition we ARE an ObjectBlock!!!!!
can return multiple blocks!
"""
# operate column-by-column
def f(mask, val, idx):
shape = val.shape
values = soft_convert_objects(
val.ravel(),
datetime=datetime,
numeric=numeric,
timedelta=timedelta,
coerce=coerce,
copy=copy,
)
if isinstance(values, np.ndarray):
# TODO: allow EA once reshape is supported
values = values.reshape(shape)
values = _block_shape(values, ndim=self.ndim)
return values
if self.ndim == 2:
blocks = self.split_and_operate(None, f, False)
else:
values = f(None, self.values.ravel(), None)
blocks = [make_block(values, ndim=self.ndim, placement=self.mgr_locs)]
return blocks
def _maybe_downcast(self, blocks: List["Block"], downcast=None) -> List["Block"]:
if downcast is not None:
return blocks
# split and convert the blocks
return _extend_blocks([b.convert(datetime=True, numeric=False) for b in blocks])
def _can_hold_element(self, element: Any) -> bool:
return True
def should_store(self, value):
return not (
issubclass(
value.dtype.type,
(np.integer, np.floating, np.complexfloating, np.datetime64, np.bool_),
)
or is_extension_array_dtype(value)
)
def replace(
self, to_replace, value, inplace=False, filter=None, regex=False, convert=True
):
to_rep_is_list = is_list_like(to_replace)
value_is_list = is_list_like(value)
both_lists = to_rep_is_list and value_is_list
either_list = to_rep_is_list or value_is_list
result_blocks = []
blocks = [self]
if not either_list and is_re(to_replace):
return self._replace_single(
to_replace,
value,
inplace=inplace,
filter=filter,
regex=True,
convert=convert,
)
elif not (either_list or regex):
return super().replace(
to_replace,
value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
elif both_lists:
for to_rep, v in zip(to_replace, value):
result_blocks = []
for b in blocks:
result = b._replace_single(
to_rep,
v,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
result_blocks = _extend_blocks(result, result_blocks)
blocks = result_blocks
return result_blocks
elif to_rep_is_list and regex:
for to_rep in to_replace:
result_blocks = []
for b in blocks:
result = b._replace_single(
to_rep,
value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
result_blocks = _extend_blocks(result, result_blocks)
blocks = result_blocks
return result_blocks
return self._replace_single(
to_replace,
value,
inplace=inplace,
filter=filter,
convert=convert,
regex=regex,
)
def _replace_single(
self,
to_replace,
value,
inplace=False,
filter=None,
regex=False,
convert=True,
mask=None,
):
"""
Replace elements by the given value.
Parameters
----------
to_replace : object or pattern
Scalar to replace or regular expression to match.
value : object
Replacement object.
inplace : bool, default False
Perform inplace modification.
filter : list, optional
regex : bool, default False
If true, perform regular expression substitution.
convert : bool, default True
If true, try to coerce any object types to better types.
mask : array-like of bool, optional
True indicate corresponding element is ignored.
Returns
-------
a new block, the result after replacing
"""
inplace = validate_bool_kwarg(inplace, "inplace")
# to_replace is regex compilable
to_rep_re = regex and is_re_compilable(to_replace)
# regex is regex compilable
regex_re = is_re_compilable(regex)
# only one will survive
if to_rep_re and regex_re:
raise AssertionError(
"only one of to_replace and regex can be regex compilable"
)
# if regex was passed as something that can be a regex (rather than a
# boolean)
if regex_re:
to_replace = regex
regex = regex_re or to_rep_re
# try to get the pattern attribute (compiled re) or it's a string
if is_re(to_replace):
pattern = to_replace.pattern
else:
pattern = to_replace
# if the pattern is not empty and to_replace is either a string or a
# regex
if regex and pattern:
rx = re.compile(to_replace)
else:
# if the thing to replace is not a string or compiled regex call
# the superclass method -> to_replace is some kind of object
return super().replace(
to_replace, value, inplace=inplace, filter=filter, regex=regex
)
new_values = self.values if inplace else self.values.copy()
# deal with replacing values with objects (strings) that match but
# whose replacement is not a string (numeric, nan, object)
if isna(value) or not isinstance(value, str):
def re_replacer(s):
if is_re(rx) and isinstance(s, str):
return value if rx.search(s) is not None else s
else:
return s
else:
# value is guaranteed to be a string here, s can be either a string
# or null if it's null it gets returned
def re_replacer(s):
if is_re(rx) and isinstance(s, str):
return rx.sub(value, s)
else:
return s
f = np.vectorize(re_replacer, otypes=[self.dtype])
if filter is None:
filt = slice(None)
else:
filt = self.mgr_locs.isin(filter).nonzero()[0]
if mask is None:
new_values[filt] = f(new_values[filt])
else:
new_values[filt][mask] = f(new_values[filt][mask])
# convert
block = self.make_block(new_values)
if convert:
block = block.convert(numeric=False)
return block
def _replace_coerce(
self, to_replace, value, inplace=True, regex=False, convert=False, mask=None
):
"""
Replace value corresponding to the given boolean array with another
value.
Parameters
----------
to_replace : object or pattern
Scalar to replace or regular expression to match.
value : object
Replacement object.
inplace : bool, default False
Perform inplace modification.
regex : bool, default False
If true, perform regular expression substitution.
convert : bool, default True
If true, try to coerce any object types to better types.
mask : array-like of bool, optional
True indicate corresponding element is ignored.
Returns
-------
A new block if there is anything to replace or the original block.
"""
if mask.any():
block = super()._replace_coerce(
to_replace=to_replace,
value=value,
inplace=inplace,
regex=regex,
convert=convert,
mask=mask,
)
if convert:
block = [b.convert(numeric=False, copy=True) for b in block]
return block
if convert:
return [self.convert(numeric=False, copy=True)]
return self
class CategoricalBlock(ExtensionBlock):
__slots__ = ()
is_categorical = True
_verify_integrity = True
_can_hold_na = True
_concatenator = staticmethod(concat_categorical)
def __init__(self, values, placement, ndim=None):
# coerce to categorical if we can
values = extract_array(values)
assert isinstance(values, Categorical), type(values)
super().__init__(values, placement=placement, ndim=ndim)
@property
def _holder(self):
return Categorical
@property
def array_dtype(self):
""" the dtype to return if I want to construct this block as an
array
"""
return np.object_
def to_dense(self):
# Categorical.get_values returns a DatetimeIndex for datetime
# categories, so we can't simply use `np.asarray(self.values)` like
# other types.
return self.values._internal_get_values()
def to_native_types(self, slicer=None, na_rep="", quoting=None, **kwargs):
""" convert to our native types format, slicing if desired """
values = self.values
if slicer is not None:
# Categorical is always one dimension
values = values[slicer]
mask = isna(values)
values = np.array(values, dtype="object")
values[mask] = na_rep
# we are expected to return a 2-d ndarray
return values.reshape(1, len(values))
def concat_same_type(self, to_concat, placement=None):
"""
Concatenate list of single blocks of the same type.
Note that this CategoricalBlock._concat_same_type *may* not
return a CategoricalBlock. When the categories in `to_concat`
differ, this will return an object ndarray.
If / when we decide we don't like that behavior:
1. Change Categorical._concat_same_type to use union_categoricals
2. Delete this method.
"""
values = self._concatenator(
[blk.values for blk in to_concat], axis=self.ndim - 1
)
# not using self.make_block_same_class as values can be object dtype
return make_block(
values, placement=placement or slice(0, len(values), 1), ndim=self.ndim
)
def replace(
self,
to_replace,
value,
inplace: bool = False,
filter=None,
regex: bool = False,
convert: bool = True,
):
inplace = validate_bool_kwarg(inplace, "inplace")
result = self if inplace else self.copy()
if filter is None: # replace was called on a series
result.values.replace(to_replace, value, inplace=True)
if convert:
return result.convert(numeric=False, copy=not inplace)
else:
return result
else: # replace was called on a DataFrame
if not isna(value):
result.values.add_categories(value, inplace=True)
return super(CategoricalBlock, result).replace(
to_replace, value, inplace, filter, regex, convert
)
# -----------------------------------------------------------------
# Constructor Helpers
def get_block_type(values, dtype=None):
"""
Find the appropriate Block subclass to use for the given values and dtype.
Parameters
----------
values : ndarray-like
dtype : numpy or pandas dtype
Returns
-------
cls : class, subclass of Block
"""
dtype = dtype or values.dtype
vtype = dtype.type
if is_sparse(dtype):
# Need this first(ish) so that Sparse[datetime] is sparse
cls = ExtensionBlock
elif is_categorical(values):
cls = CategoricalBlock
elif issubclass(vtype, np.datetime64):
assert not is_datetime64tz_dtype(values)
cls = DatetimeBlock
elif is_datetime64tz_dtype(values):
cls = DatetimeTZBlock
elif is_interval_dtype(dtype) or is_period_dtype(dtype):
cls = ObjectValuesExtensionBlock
elif is_extension_array_dtype(values):
cls = ExtensionBlock
elif issubclass(vtype, np.floating):
cls = FloatBlock
elif issubclass(vtype, np.timedelta64):
assert issubclass(vtype, np.integer)
cls = TimeDeltaBlock
elif issubclass(vtype, np.complexfloating):
cls = ComplexBlock
elif issubclass(vtype, np.integer):
cls = IntBlock
elif dtype == np.bool_:
cls = BoolBlock
else:
cls = ObjectBlock
return cls
def make_block(values, placement, klass=None, ndim=None, dtype=None):
# Ensure that we don't allow PandasArray / PandasDtype in internals.
# For now, blocks should be backed by ndarrays when possible.
if isinstance(values, ABCPandasArray):
values = values.to_numpy()
if ndim and ndim > 1:
values = np.atleast_2d(values)
if isinstance(dtype, PandasDtype):
dtype = dtype.numpy_dtype
if klass is None:
dtype = dtype or values.dtype
klass = get_block_type(values, dtype)
elif klass is DatetimeTZBlock and not is_datetime64tz_dtype(values):
# TODO: This is no longer hit internally; does it need to be retained
# for e.g. pyarrow?
values = DatetimeArray._simple_new(values, dtype=dtype)
return klass(values, ndim=ndim, placement=placement)
# -----------------------------------------------------------------
def _extend_blocks(result, blocks=None):
""" return a new extended blocks, given the result """
if blocks is None:
blocks = []
if isinstance(result, list):
for r in result:
if isinstance(r, list):
blocks.extend(r)
else:
blocks.append(r)
else:
assert isinstance(result, Block), type(result)
blocks.append(result)
return blocks
def _block_shape(values, ndim=1, shape=None):
""" guarantee the shape of the values to be at least 1 d """
if values.ndim < ndim:
if shape is None:
shape = values.shape
if not is_extension_array_dtype(values):
# TODO: https://github.com/pandas-dev/pandas/issues/23023
# block.shape is incorrect for "2D" ExtensionArrays
# We can't, and don't need to, reshape.
values = values.reshape(tuple((1,) + shape))
return values
def _merge_blocks(blocks, dtype=None, _can_consolidate=True):
if len(blocks) == 1:
return blocks[0]
if _can_consolidate:
if dtype is None:
if len({b.dtype for b in blocks}) != 1:
raise AssertionError("_merge_blocks are invalid!")
# FIXME: optimization potential in case all mgrs contain slices and
# combination of those slices is a slice, too.
new_mgr_locs = np.concatenate([b.mgr_locs.as_array for b in blocks])
new_values = np.vstack([b.values for b in blocks])
argsort = np.argsort(new_mgr_locs)
new_values = new_values[argsort]
new_mgr_locs = new_mgr_locs[argsort]
return make_block(new_values, placement=new_mgr_locs)
# no merge
return blocks
def _safe_reshape(arr, new_shape):
"""
If possible, reshape `arr` to have shape `new_shape`,
with a couple of exceptions (see gh-13012):
1) If `arr` is a ExtensionArray or Index, `arr` will be
returned as is.
2) If `arr` is a Series, the `_values` attribute will
be reshaped and returned.
Parameters
----------
arr : array-like, object to be reshaped
new_shape : int or tuple of ints, the new shape
"""
if isinstance(arr, ABCSeries):
arr = arr._values
if not isinstance(arr, ABCExtensionArray):
arr = arr.reshape(new_shape)
return arr
def _putmask_smart(v, mask, n):
"""
Return a new ndarray, try to preserve dtype if possible.
Parameters
----------
v : `values`, updated in-place (array like)
mask : np.ndarray
Applies to both sides (array like).
n : `new values` either scalar or an array like aligned with `values`
Returns
-------
values : ndarray with updated values
this *may* be a copy of the original
See Also
--------
ndarray.putmask
"""
# we cannot use np.asarray() here as we cannot have conversions
# that numpy does when numeric are mixed with strings
# n should be the length of the mask or a scalar here
if not is_list_like(n):
n = np.repeat(n, len(mask))
# see if we are only masking values that if putted
# will work in the current dtype
try:
nn = n[mask]
except TypeError:
# TypeError: only integer scalar arrays can be converted to a scalar index
pass
else:
# make sure that we have a nullable type
# if we have nulls
if not _isna_compat(v, nn[0]):
pass
elif not (is_float_dtype(nn.dtype) or is_integer_dtype(nn.dtype)):
# only compare integers/floats
pass
elif not (is_float_dtype(v.dtype) or is_integer_dtype(v.dtype)):
# only compare integers/floats
pass
else:
# we ignore ComplexWarning here
with warnings.catch_warnings(record=True):
warnings.simplefilter("ignore", np.ComplexWarning)
nn_at = nn.astype(v.dtype)
comp = nn == nn_at
if is_list_like(comp) and comp.all():
nv = v.copy()
nv[mask] = nn_at
return nv
n = np.asarray(n)
def _putmask_preserve(nv, n):
try:
nv[mask] = n[mask]
except (IndexError, ValueError):
nv[mask] = n
return nv
# preserves dtype if possible
if v.dtype.kind == n.dtype.kind:
return _putmask_preserve(v, n)
# change the dtype if needed
dtype, _ = maybe_promote(n.dtype)
if is_extension_array_dtype(v.dtype) and is_object_dtype(dtype):
v = v._internal_get_values(dtype)
else:
v = v.astype(dtype)
return _putmask_preserve(v, n)
from datetime import datetime, timedelta
import functools
import inspect
import re
from typing import Any, List
import warnings
import numpy as np
from pandas._libs import NaT, Timestamp, algos as libalgos, lib, tslib, writers
from pandas._libs.index import convert_scalar
import pandas._libs.internals as libinternals
from pandas._libs.tslibs import Timedelta, conversion
from pandas._libs.tslibs.timezones import tz_compare
from pandas.util._validators import validate_bool_kwarg
from pandas.core.dtypes.cast import (
astype_nansafe,
find_common_type,
infer_dtype_from,
infer_dtype_from_scalar,
maybe_downcast_numeric,
maybe_downcast_to_dtype,
maybe_infer_dtype_type,
maybe_promote,
maybe_upcast,
soft_convert_objects,
)
from pandas.core.dtypes.common import (
_NS_DTYPE,
_TD_DTYPE,
ensure_platform_int,
is_bool_dtype,
is_categorical,
is_categorical_dtype,
is_datetime64_dtype,
is_datetime64tz_dtype,
is_dtype_equal,
is_extension_array_dtype,
is_float_dtype,
is_integer,
is_integer_dtype,
is_interval_dtype,
is_list_like,
is_object_dtype,
is_period_dtype,
is_re,
is_re_compilable,
is_sparse,
is_timedelta64_dtype,
pandas_dtype,
)
from pandas.core.dtypes.concat import concat_categorical, concat_datetime
from pandas.core.dtypes.dtypes import CategoricalDtype, ExtensionDtype
from pandas.core.dtypes.generic import (
ABCDataFrame,
ABCExtensionArray,
ABCPandasArray,
ABCSeries,
)
from pandas.core.dtypes.missing import (
_isna_compat,
array_equivalent,
is_valid_nat_for_dtype,
isna,
)
import pandas.core.algorithms as algos
from pandas.core.arrays import (
Categorical,
DatetimeArray,
ExtensionArray,
PandasArray,
PandasDtype,
TimedeltaArray,
)
from pandas.core.base import PandasObject
import pandas.core.common as com
from pandas.core.construction import extract_array
from pandas.core.indexers import (
check_setitem_lengths,
is_empty_indexer,
is_scalar_indexer,
)
import pandas.core.missing as missing
from pandas.core.nanops import nanpercentile
from pandas.io.formats.printing import pprint_thing
class Block(PandasObject):
"""
Canonical n-dimensional unit of homogeneous dtype contained in a pandas
data structure
Index-ignorant; let the container take care of that
"""
__slots__ = ["_mgr_locs", "values", "ndim"]
is_numeric = False
is_float = False
is_integer = False
is_complex = False
is_datetime = False
is_datetimetz = False
is_timedelta = False
is_bool = False
is_object = False
is_categorical = False
is_extension = False
_can_hold_na = False
_can_consolidate = True
_verify_integrity = True
_validate_ndim = True
_ftype = "dense"
_concatenator = staticmethod(np.concatenate)
def __init__(self, values, placement, ndim=None):
self.ndim = self._check_ndim(values, ndim)
self.mgr_locs = placement
self.values = values
if self._validate_ndim and self.ndim and len(self.mgr_locs) != len(self.values):
raise ValueError(
f"Wrong number of items passed {len(self.values)}, "
f"placement implies {len(self.mgr_locs)}"
)
def _check_ndim(self, values, ndim):
"""
ndim inference and validation.
Infers ndim from 'values' if not provided to __init__.
Validates that values.ndim and ndim are consistent if and only if
the class variable '_validate_ndim' is True.
Parameters
----------
values : array-like
ndim : int or None
Returns
-------
ndim : int
Raises
------
ValueError : the number of dimensions do not match
"""
if ndim is None:
ndim = values.ndim
if self._validate_ndim and values.ndim != ndim:
raise ValueError(
"Wrong number of dimensions. "
f"values.ndim != ndim [{values.ndim} != {ndim}]"
)
return ndim
@property
def _holder(self):
"""The array-like that can hold the underlying values.
None for 'Block', overridden by subclasses that don't
use an ndarray.
"""
return None
@property
def _consolidate_key(self):
return (self._can_consolidate, self.dtype.name)
@property
def _is_single_block(self):
return self.ndim == 1
@property
def is_view(self):
""" return a boolean if I am possibly a view """
return self.values.base is not None
@property
def is_datelike(self):
""" return True if I am a non-datelike """
return self.is_datetime or self.is_timedelta
def is_categorical_astype(self, dtype):
"""
validate that we have a astypeable to categorical,
returns a boolean if we are a categorical
"""
if dtype is Categorical or dtype is CategoricalDtype:
# this is a pd.Categorical, but is not
# a valid type for astypeing
raise TypeError(f"invalid type {dtype} for astype")
elif is_categorical_dtype(dtype):
return True
return False
def external_values(self):
"""
The array that Series.values returns (public attribute).
This has some historical constraints, and is overridden in block
subclasses to return the correct array (e.g. period returns
object ndarray and datetimetz a datetime64[ns] ndarray instead of
proper extension array).
"""
return self.values
def internal_values(self):
"""
The array that Series._values returns (internal values).
"""
return self.values
def array_values(self) -> ExtensionArray:
"""
The array that Series.array returns. Always an ExtensionArray.
"""
return PandasArray(self.values)
def get_values(self, dtype=None):
"""
return an internal format, currently just the ndarray
this is often overridden to handle to_dense like operations
"""
if is_object_dtype(dtype):
return self.values.astype(object)
return self.values
def get_block_values(self, dtype=None):
"""
This is used in the JSON C code
"""
return self.get_values(dtype=dtype)
def to_dense(self):
return self.values.view()
@property
def fill_value(self):
return np.nan
@property
def mgr_locs(self):
return self._mgr_locs
@mgr_locs.setter
def mgr_locs(self, new_mgr_locs):
if not isinstance(new_mgr_locs, libinternals.BlockPlacement):
new_mgr_locs = libinternals.BlockPlacement(new_mgr_locs)
self._mgr_locs = new_mgr_locs
@property
def array_dtype(self):
""" the dtype to return if I want to construct this block as an
array
"""
return self.dtype
def make_block(self, values, placement=None) -> "Block":
"""
Create a new block, with type inference propagate any values that are
not specified
"""
if placement is None:
placement = self.mgr_locs
return make_block(values, placement=placement, ndim=self.ndim)
def make_block_same_class(self, values, placement=None, ndim=None):
""" Wrap given values in a block of same type as self. """
if placement is None:
placement = self.mgr_locs
if ndim is None:
ndim = self.ndim
return make_block(values, placement=placement, ndim=ndim, klass=type(self))
def __repr__(self) -> str:
# don't want to print out all of the items here
name = type(self).__name__
if self._is_single_block:
result = f"{name}: {len(self)} dtype: {self.dtype}"
else:
shape = " x ".join(pprint_thing(s) for s in self.shape)
result = (
f"{name}: {pprint_thing(self.mgr_locs.indexer)}, "
f"{shape}, dtype: {self.dtype}"
)
return result
def __len__(self) -> int:
return len(self.values)
def __getstate__(self):
return self.mgr_locs.indexer, self.values
def __setstate__(self, state):
self.mgr_locs = libinternals.BlockPlacement(state[0])
self.values = state[1]
self.ndim = self.values.ndim
def _slice(self, slicer):
""" return a slice of my values """
return self.values[slicer]
def getitem_block(self, slicer, new_mgr_locs=None):
"""
Perform __getitem__-like, return result as block.
As of now, only supports slices that preserve dimensionality.
"""
if new_mgr_locs is None:
if isinstance(slicer, tuple):
axis0_slicer = slicer[0]
else:
axis0_slicer = slicer
new_mgr_locs = self.mgr_locs[axis0_slicer]
new_values = self._slice(slicer)
if self._validate_ndim and new_values.ndim != self.ndim:
raise ValueError("Only same dim slicing is allowed")
return self.make_block_same_class(new_values, new_mgr_locs)
@property
def shape(self):
return self.values.shape
@property
def dtype(self):
return self.values.dtype
@property
def ftype(self):
if getattr(self.values, "_pandas_ftype", False):
dtype = self.dtype.subtype
else:
dtype = self.dtype
return f"{dtype}:{self._ftype}"
def merge(self, other):
return _merge_blocks([self, other])
def concat_same_type(self, to_concat, placement=None):
"""
Concatenate list of single blocks of the same type.
"""
values = self._concatenator(
[blk.values for blk in to_concat], axis=self.ndim - 1
)
return self.make_block_same_class(
values, placement=placement or slice(0, len(values), 1)
)
def iget(self, i):
return self.values[i]
def set(self, locs, values):
"""
Modify Block in-place with new item value
Returns
-------
None
"""
self.values[locs] = values
def delete(self, loc):
"""
Delete given loc(-s) from block in-place.
"""
self.values = np.delete(self.values, loc, 0)
self.mgr_locs = self.mgr_locs.delete(loc)
def apply(self, func, **kwargs) -> List["Block"]:
""" apply the function to my values; return a block if we are not
one
"""
with np.errstate(all="ignore"):
result = func(self.values, **kwargs)
return self._split_op_result(result)
def _split_op_result(self, result) -> List["Block"]:
# See also: split_and_operate
if is_extension_array_dtype(result) and result.ndim > 1:
# if we get a 2D ExtensionArray, we need to split it into 1D pieces
nbs = []
for i, loc in enumerate(self.mgr_locs):
vals = result[i]
nv = _block_shape(vals, ndim=self.ndim)
block = self.make_block(values=nv, placement=[loc])
nbs.append(block)
return nbs
if not isinstance(result, Block):
result = self.make_block(values=_block_shape(result, ndim=self.ndim))
return [result]
def fillna(self, value, limit=None, inplace=False, downcast=None):
""" fillna on the block with the value. If we fail, then convert to
ObjectBlock and try again
"""
inplace = validate_bool_kwarg(inplace, "inplace")
mask = isna(self.values)
if limit is not None:
limit = libalgos._validate_limit(None, limit=limit)
mask[mask.cumsum(self.ndim - 1) > limit] = False
if not self._can_hold_na:
if inplace:
return self
else:
return self.copy()
if self._can_hold_element(value):
# equivalent: _try_coerce_args(value) would not raise
blocks = self.putmask(mask, value, inplace=inplace)
return self._maybe_downcast(blocks, downcast)
# we can't process the value, but nothing to do
if not mask.any():
return self if inplace else self.copy()
# operate column-by-column
def f(mask, val, idx):
block = self.coerce_to_target_dtype(value)
# slice out our block
if idx is not None:
# i.e. self.ndim == 2
block = block.getitem_block(slice(idx, idx + 1))
return block.fillna(value, limit=limit, inplace=inplace, downcast=None)
return self.split_and_operate(None, f, inplace)
def split_and_operate(self, mask, f, inplace: bool):
"""
split the block per-column, and apply the callable f
per-column, return a new block for each. Handle
masking which will not change a block unless needed.
Parameters
----------
mask : 2-d boolean mask
f : callable accepting (1d-mask, 1d values, indexer)
inplace : boolean
Returns
-------
list of blocks
"""
if mask is None:
mask = np.broadcast_to(True, shape=self.shape)
new_values = self.values
def make_a_block(nv, ref_loc):
if isinstance(nv, list):
assert len(nv) == 1, nv
assert isinstance(nv[0], Block)
block = nv[0]
else:
# Put back the dimension that was taken from it and make
# a block out of the result.
nv = _block_shape(nv, ndim=self.ndim)
block = self.make_block(values=nv, placement=ref_loc)
return block
# ndim == 1
if self.ndim == 1:
if mask.any():
nv = f(mask, new_values, None)
else:
nv = new_values if inplace else new_values.copy()
block = make_a_block(nv, self.mgr_locs)
return [block]
# ndim > 1
new_blocks = []
for i, ref_loc in enumerate(self.mgr_locs):
m = mask[i]
v = new_values[i]
# need a new block
if m.any():
nv = f(m, v, i)
else:
nv = v if inplace else v.copy()
block = make_a_block(nv, [ref_loc])
new_blocks.append(block)
return new_blocks
def _maybe_downcast(self, blocks: List["Block"], downcast=None) -> List["Block"]:
# no need to downcast our float
# unless indicated
if downcast is None and (
self.is_float or self.is_timedelta or self.is_datetime
):
return blocks
return _extend_blocks([b.downcast(downcast) for b in blocks])
def downcast(self, dtypes=None):
""" try to downcast each item to the dict of dtypes if present """
# turn it off completely
if dtypes is False:
return self
values = self.values
# single block handling
if self._is_single_block:
# try to cast all non-floats here
if dtypes is None:
dtypes = "infer"
nv = maybe_downcast_to_dtype(values, dtypes)
return self.make_block(nv)
# ndim > 1
if dtypes is None:
return self
if not (dtypes == "infer" or isinstance(dtypes, dict)):
raise ValueError(
"downcast must have a dictionary or 'infer' as its argument"
)
elif dtypes != "infer":
raise AssertionError("dtypes as dict is not supported yet")
# operate column-by-column
# this is expensive as it splits the blocks items-by-item
def f(mask, val, idx):
val = maybe_downcast_to_dtype(val, dtype="infer")
return val
return self.split_and_operate(None, f, False)
def astype(self, dtype, copy: bool = False, errors: str = "raise"):
"""
Coerce to the new dtype.
Parameters
----------
dtype : str, dtype convertible
copy : bool, default False
copy if indicated
errors : str, {'raise', 'ignore'}, default 'ignore'
- ``raise`` : allow exceptions to be raised
- ``ignore`` : suppress exceptions. On error return original object
Returns
-------
Block
"""
errors_legal_values = ("raise", "ignore")
if errors not in errors_legal_values:
invalid_arg = (
"Expected value of kwarg 'errors' to be one of "
f"{list(errors_legal_values)}. Supplied value is '{errors}'"
)
raise ValueError(invalid_arg)
if inspect.isclass(dtype) and issubclass(dtype, ExtensionDtype):
msg = (
f"Expected an instance of {dtype.__name__}, "
"but got the class instead. Try instantiating 'dtype'."
)
raise TypeError(msg)
# may need to convert to categorical
if self.is_categorical_astype(dtype):
if is_categorical_dtype(self.values):
# GH 10696/18593: update an existing categorical efficiently
return self.make_block(self.values.astype(dtype, copy=copy))
return self.make_block(Categorical(self.values, dtype=dtype))
dtype = pandas_dtype(dtype)
# astype processing
if is_dtype_equal(self.dtype, dtype):
if copy:
return self.copy()
return self
# force the copy here
if self.is_extension:
# TODO: Should we try/except this astype?
values = self.values.astype(dtype)
else:
if issubclass(dtype.type, str):
# use native type formatting for datetime/tz/timedelta
if self.is_datelike:
values = self.to_native_types()
# astype formatting
else:
values = self.get_values()
else:
values = self.get_values(dtype=dtype)
# _astype_nansafe works fine with 1-d only
vals1d = values.ravel()
try:
values = astype_nansafe(vals1d, dtype, copy=True)
except (ValueError, TypeError):
# e.g. astype_nansafe can fail on object-dtype of strings
# trying to convert to float
if errors == "raise":
raise
newb = self.copy() if copy else self
return newb
# TODO(extension)
# should we make this attribute?
if isinstance(values, np.ndarray):
values = values.reshape(self.shape)
newb = make_block(values, placement=self.mgr_locs, ndim=self.ndim)
if newb.is_numeric and self.is_numeric:
if newb.shape != self.shape:
raise TypeError(
f"cannot set astype for copy = [{copy}] for dtype "
f"({self.dtype.name} [{self.shape}]) to different shape "
f"({newb.dtype.name} [{newb.shape}])"
)
return newb
def convert(
self,
copy: bool = True,
datetime: bool = True,
numeric: bool = True,
timedelta: bool = True,
coerce: bool = False,
):
""" attempt to coerce any object types to better types return a copy
of the block (if copy = True) by definition we are not an ObjectBlock
here!
"""
return self.copy() if copy else self
def _can_hold_element(self, element: Any) -> bool:
""" require the same dtype as ourselves """
dtype = self.values.dtype.type
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return issubclass(tipo.type, dtype)
return isinstance(element, dtype)
def to_native_types(self, slicer=None, na_rep="nan", quoting=None, **kwargs):
""" convert to our native types format, slicing if desired """
values = self.get_values()
if slicer is not None:
values = values[:, slicer]
mask = isna(values)
itemsize = writers.word_len(na_rep)
if not self.is_object and not quoting and itemsize:
values = values.astype(str)
if values.dtype.itemsize / np.dtype("U1").itemsize < itemsize:
# enlarge for the na_rep
values = values.astype(f"<U{itemsize}")
else:
values = np.array(values, dtype="object")
values[mask] = na_rep
return values
# block actions #
def copy(self, deep=True):
""" copy constructor """
values = self.values
if deep:
values = values.copy()
return self.make_block_same_class(values, ndim=self.ndim)
def replace(
self, to_replace, value, inplace=False, filter=None, regex=False, convert=True
):
"""replace the to_replace value with value, possible to create new
blocks here this is just a call to putmask. regex is not used here.
It is used in ObjectBlocks. It is here for API compatibility.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
original_to_replace = to_replace
# If we cannot replace with own dtype, convert to ObjectBlock and
# retry
if not self._can_hold_element(to_replace):
if not isinstance(to_replace, list):
if inplace:
return [self]
return [self.copy()]
to_replace = [x for x in to_replace if self._can_hold_element(x)]
if not len(to_replace):
# GH#28084 avoid costly checks since we can infer
# that there is nothing to replace in this block
if inplace:
return [self]
return [self.copy()]
if len(to_replace) == 1:
# _can_hold_element checks have reduced this back to the
# scalar case and we can avoid a costly object cast
return self.replace(
to_replace[0],
value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
# GH 22083, TypeError or ValueError occurred within error handling
# causes infinite loop. Cast and retry only if not objectblock.
if is_object_dtype(self):
raise AssertionError
# try again with a compatible block
block = self.astype(object)
return block.replace(
to_replace=to_replace,
value=value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
values = self.values
if lib.is_scalar(to_replace) and isinstance(values, np.ndarray):
# The only non-DatetimeLike class that also has a non-trivial
# try_coerce_args is ObjectBlock, but that overrides replace,
# so does not get here.
to_replace = convert_scalar(values, to_replace)
mask = missing.mask_missing(values, to_replace)
if filter is not None:
filtered_out = ~self.mgr_locs.isin(filter)
mask[filtered_out.nonzero()[0]] = False
if not mask.any():
if inplace:
return [self]
return [self.copy()]
try:
blocks = self.putmask(mask, value, inplace=inplace)
# Note: it is _not_ the case that self._can_hold_element(value)
# is always true at this point. In particular, that can fail
# for:
# "2u" with bool-dtype, float-dtype
# 0.5 with int64-dtype
# np.nan with int64-dtype
except (TypeError, ValueError):
# GH 22083, TypeError or ValueError occurred within error handling
# causes infinite loop. Cast and retry only if not objectblock.
if is_object_dtype(self):
raise
assert not self._can_hold_element(value), value
# try again with a compatible block
block = self.astype(object)
return block.replace(
to_replace=original_to_replace,
value=value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
if convert:
blocks = [b.convert(numeric=False, copy=not inplace) for b in blocks]
return blocks
def _replace_single(self, *args, **kwargs):
""" no-op on a non-ObjectBlock """
return self if kwargs["inplace"] else self.copy()
def setitem(self, indexer, value):
"""
Set the value inplace, returning a a maybe different typed block.
Parameters
----------
indexer : tuple, list-like, array-like, slice
The subset of self.values to set
value : object
The value being set
Returns
-------
Block
Notes
-----
`indexer` is a direct slice/positional indexer. `value` must
be a compatible shape.
"""
transpose = self.ndim == 2
# coerce None values, if appropriate
if value is None:
if self.is_numeric:
value = np.nan
# coerce if block dtype can store value
values = self.values
if self._can_hold_element(value):
# We only get here for non-Extension Blocks, so _try_coerce_args
# is only relevant for DatetimeBlock and TimedeltaBlock
if lib.is_scalar(value):
value = convert_scalar(values, value)
else:
# current dtype cannot store value, coerce to common dtype
find_dtype = False
if hasattr(value, "dtype"):
dtype = value.dtype
find_dtype = True
elif lib.is_scalar(value) and not isna(value):
dtype, _ = infer_dtype_from_scalar(value, pandas_dtype=True)
find_dtype = True
if find_dtype:
dtype = find_common_type([values.dtype, dtype])
if not is_dtype_equal(self.dtype, dtype):
b = self.astype(dtype)
return b.setitem(indexer, value)
# value must be storeable at this moment
if is_extension_array_dtype(getattr(value, "dtype", None)):
# We need to be careful not to allow through strings that
# can be parsed to EADtypes
arr_value = value
else:
arr_value = np.array(value)
# cast the values to a type that can hold nan (if necessary)
if not self._can_hold_element(value):
dtype, _ = maybe_promote(arr_value.dtype)
values = values.astype(dtype)
if transpose:
values = values.T
# length checking
check_setitem_lengths(indexer, value, values)
exact_match = (
len(arr_value.shape)
and arr_value.shape[0] == values.shape[0]
and arr_value.size == values.size
)
if is_empty_indexer(indexer, arr_value):
# GH#8669 empty indexers
pass
elif is_scalar_indexer(indexer, arr_value):
# setting a single element for each dim and with a rhs that could
# be e.g. a list; see GH#6043
values[indexer] = value
elif (
exact_match
and is_categorical_dtype(arr_value.dtype)
and not is_categorical_dtype(values)
):
# GH25495 - If the current dtype is not categorical,
# we need to create a new categorical block
values[indexer] = value
return self.make_block(Categorical(self.values, dtype=arr_value.dtype))
# if we are an exact match (ex-broadcasting),
# then use the resultant dtype
elif exact_match:
values[indexer] = value
try:
values = values.astype(arr_value.dtype)
except ValueError:
pass
# set
else:
values[indexer] = value
if transpose:
values = values.T
block = self.make_block(values)
return block
def putmask(self, mask, new, align=True, inplace=False, axis=0, transpose=False):
""" putmask the data to the block; it is possible that we may create a
new dtype of block
return the resulting block(s)
Parameters
----------
mask : the condition to respect
new : a ndarray/object
align : boolean, perform alignment on other/cond, default is True
inplace : perform inplace modification, default is False
axis : int
transpose : boolean
Set to True if self is stored with axes reversed
Returns
-------
a list of new blocks, the result of the putmask
"""
new_values = self.values if inplace else self.values.copy()
new = getattr(new, "values", new)
mask = getattr(mask, "values", mask)
# if we are passed a scalar None, convert it here
if not is_list_like(new) and isna(new) and not self.is_object:
# FIXME: make sure we have compatible NA
new = self.fill_value
if self._can_hold_element(new):
# We only get here for non-Extension Blocks, so _try_coerce_args
# is only relevant for DatetimeBlock and TimedeltaBlock
if lib.is_scalar(new):
new = convert_scalar(new_values, new)
if transpose:
new_values = new_values.T
# If the default repeat behavior in np.putmask would go in the
# wrong direction, then explicitly repeat and reshape new instead
if getattr(new, "ndim", 0) >= 1:
if self.ndim - 1 == new.ndim and axis == 1:
new = np.repeat(new, new_values.shape[-1]).reshape(self.shape)
new = new.astype(new_values.dtype)
# we require exact matches between the len of the
# values we are setting (or is compat). np.putmask
# doesn't check this and will simply truncate / pad
# the output, but we want sane error messages
#
# TODO: this prob needs some better checking
# for 2D cases
if (
is_list_like(new)
and np.any(mask[mask])
and getattr(new, "ndim", 1) == 1
):
if mask[mask].shape[-1] == len(new):
# GH 30567
# If length of ``new`` is less than the length of ``new_values``,
# `np.putmask` would first repeat the ``new`` array and then
# assign the masked values hence produces incorrect result.
# `np.place` on the other hand uses the ``new`` values at it is
# to place in the masked locations of ``new_values``
np.place(new_values, mask, new)
elif mask.shape[-1] == len(new) or len(new) == 1:
np.putmask(new_values, mask, new)
else:
raise ValueError("cannot assign mismatch length to masked array")
else:
np.putmask(new_values, mask, new)
# maybe upcast me
elif mask.any():
if transpose:
mask = mask.T
if isinstance(new, np.ndarray):
new = new.T
axis = new_values.ndim - axis - 1
# Pseudo-broadcast
if getattr(new, "ndim", 0) >= 1:
if self.ndim - 1 == new.ndim:
new_shape = list(new.shape)
new_shape.insert(axis, 1)
new = new.reshape(tuple(new_shape))
# operate column-by-column
def f(mask, val, idx):
if idx is None:
# ndim==1 case.
n = new
else:
if isinstance(new, np.ndarray):
n = np.squeeze(new[idx % new.shape[0]])
else:
n = np.array(new)
# type of the new block
dtype, _ = maybe_promote(n.dtype)
# we need to explicitly astype here to make a copy
n = n.astype(dtype)
nv = _putmask_smart(val, mask, n)
return nv
new_blocks = self.split_and_operate(mask, f, inplace)
return new_blocks
if inplace:
return [self]
if transpose:
new_values = new_values.T
return [self.make_block(new_values)]
def coerce_to_target_dtype(self, other):
"""
coerce the current block to a dtype compat for other
we will return a block, possibly object, and not raise
we can also safely try to coerce to the same dtype
and will receive the same block
"""
# if we cannot then coerce to object
dtype, _ = infer_dtype_from(other, pandas_dtype=True)
if is_dtype_equal(self.dtype, dtype):
return self
if self.is_bool or is_object_dtype(dtype) or is_bool_dtype(dtype):
# we don't upcast to bool
return self.astype(object)
elif (self.is_float or self.is_complex) and (
is_integer_dtype(dtype) or is_float_dtype(dtype)
):
# don't coerce float/complex to int
return self
elif (
self.is_datetime
or is_datetime64_dtype(dtype)
or is_datetime64tz_dtype(dtype)
):
# not a datetime
if not (
(is_datetime64_dtype(dtype) or is_datetime64tz_dtype(dtype))
and self.is_datetime
):
return self.astype(object)
# don't upcast timezone with different timezone or no timezone
mytz = getattr(self.dtype, "tz", None)
othertz = getattr(dtype, "tz", None)
if not tz_compare(mytz, othertz):
return self.astype(object)
raise AssertionError(
f"possible recursion in coerce_to_target_dtype: {self} {other}"
)
elif self.is_timedelta or is_timedelta64_dtype(dtype):
# not a timedelta
if not (is_timedelta64_dtype(dtype) and self.is_timedelta):
return self.astype(object)
raise AssertionError(
f"possible recursion in coerce_to_target_dtype: {self} {other}"
)
try:
return self.astype(dtype)
except (ValueError, TypeError, OverflowError):
return self.astype(object)
def interpolate(
self,
method="pad",
axis=0,
index=None,
values=None,
inplace=False,
limit=None,
limit_direction="forward",
limit_area=None,
fill_value=None,
coerce=False,
downcast=None,
**kwargs,
):
inplace = validate_bool_kwarg(inplace, "inplace")
def check_int_bool(self, inplace):
# Only FloatBlocks will contain NaNs.
# timedelta subclasses IntBlock
if (self.is_bool or self.is_integer) and not self.is_timedelta:
if inplace:
return self
else:
return self.copy()
# a fill na type method
try:
m = missing.clean_fill_method(method)
except ValueError:
m = None
if m is not None:
r = check_int_bool(self, inplace)
if r is not None:
return r
return self._interpolate_with_fill(
method=m,
axis=axis,
inplace=inplace,
limit=limit,
fill_value=fill_value,
coerce=coerce,
downcast=downcast,
)
# validate the interp method
m = missing.clean_interp_method(method, **kwargs)
r = check_int_bool(self, inplace)
if r is not None:
return r
return self._interpolate(
method=m,
index=index,
values=values,
axis=axis,
limit=limit,
limit_direction=limit_direction,
limit_area=limit_area,
fill_value=fill_value,
inplace=inplace,
downcast=downcast,
**kwargs,
)
def _interpolate_with_fill(
self,
method="pad",
axis=0,
inplace=False,
limit=None,
fill_value=None,
coerce=False,
downcast=None,
):
""" fillna but using the interpolate machinery """
inplace = validate_bool_kwarg(inplace, "inplace")
# if we are coercing, then don't force the conversion
# if the block can't hold the type
if coerce:
if not self._can_hold_na:
if inplace:
return [self]
else:
return [self.copy()]
values = self.values if inplace else self.values.copy()
# We only get here for non-ExtensionBlock
fill_value = convert_scalar(self.values, fill_value)
values = missing.interpolate_2d(
values,
method=method,
axis=axis,
limit=limit,
fill_value=fill_value,
dtype=self.dtype,
)
blocks = [self.make_block_same_class(values, ndim=self.ndim)]
return self._maybe_downcast(blocks, downcast)
def _interpolate(
self,
method=None,
index=None,
values=None,
fill_value=None,
axis=0,
limit=None,
limit_direction="forward",
limit_area=None,
inplace=False,
downcast=None,
**kwargs,
):
""" interpolate using scipy wrappers """
inplace = validate_bool_kwarg(inplace, "inplace")
data = self.values if inplace else self.values.copy()
# only deal with floats
if not self.is_float:
if not self.is_integer:
return self
data = data.astype(np.float64)
if fill_value is None:
fill_value = self.fill_value
if method in ("krogh", "piecewise_polynomial", "pchip"):
if not index.is_monotonic:
raise ValueError(
f"{method} interpolation requires that the index be monotonic."
)
# process 1-d slices in the axis direction
def func(x):
# process a 1-d slice, returning it
# should the axis argument be handled below in apply_along_axis?
# i.e. not an arg to missing.interpolate_1d
return missing.interpolate_1d(
index,
x,
method=method,
limit=limit,
limit_direction=limit_direction,
limit_area=limit_area,
fill_value=fill_value,
bounds_error=False,
**kwargs,
)
# interp each column independently
interp_values = np.apply_along_axis(func, axis, data)
blocks = [self.make_block_same_class(interp_values)]
return self._maybe_downcast(blocks, downcast)
def take_nd(self, indexer, axis, new_mgr_locs=None, fill_tuple=None):
"""
Take values according to indexer and return them as a block.bb
"""
# algos.take_nd dispatches for DatetimeTZBlock, CategoricalBlock
# so need to preserve types
# sparse is treated like an ndarray, but needs .get_values() shaping
values = self.values
if fill_tuple is None:
fill_value = self.fill_value
allow_fill = False
else:
fill_value = fill_tuple[0]
allow_fill = True
new_values = algos.take_nd(
values, indexer, axis=axis, allow_fill=allow_fill, fill_value=fill_value
)
# Called from three places in managers, all of which satisfy
# this assertion
assert not (axis == 0 and new_mgr_locs is None)
if new_mgr_locs is None:
new_mgr_locs = self.mgr_locs
if not is_dtype_equal(new_values.dtype, self.dtype):
return self.make_block(new_values, new_mgr_locs)
else:
return self.make_block_same_class(new_values, new_mgr_locs)
def diff(self, n: int, axis: int = 1) -> List["Block"]:
""" return block for the diff of the values """
new_values = algos.diff(self.values, n, axis=axis, stacklevel=7)
# We use block_shape for ExtensionBlock subclasses, which may call here
# via a super.
new_values = _block_shape(new_values, ndim=self.ndim)
return [self.make_block(values=new_values)]
def shift(self, periods, axis=0, fill_value=None):
""" shift the block by periods, possibly upcast """
# convert integer to float if necessary. need to do a lot more than
# that, handle boolean etc also
new_values, fill_value = maybe_upcast(self.values, fill_value)
# make sure array sent to np.roll is c_contiguous
f_ordered = new_values.flags.f_contiguous
if f_ordered:
new_values = new_values.T
axis = new_values.ndim - axis - 1
if np.prod(new_values.shape):
new_values = np.roll(new_values, ensure_platform_int(periods), axis=axis)
axis_indexer = [slice(None)] * self.ndim
if periods > 0:
axis_indexer[axis] = slice(None, periods)
else:
axis_indexer[axis] = slice(periods, None)
new_values[tuple(axis_indexer)] = fill_value
# restore original order
if f_ordered:
new_values = new_values.T
return [self.make_block(new_values)]
def where(
self,
other,
cond,
align=True,
errors="raise",
try_cast: bool = False,
axis: int = 0,
) -> List["Block"]:
"""
evaluate the block; return result block(s) from the result
Parameters
----------
other : a ndarray/object
cond : the condition to respect
align : boolean, perform alignment on other/cond
errors : str, {'raise', 'ignore'}, default 'raise'
- ``raise`` : allow exceptions to be raised
- ``ignore`` : suppress exceptions. On error return original object
axis : int
Returns
-------
a new block(s), the result of the func
"""
import pandas.core.computation.expressions as expressions
assert errors in ["raise", "ignore"]
transpose = self.ndim == 2
values = self.values
orig_other = other
if transpose:
values = values.T
other = getattr(other, "_values", getattr(other, "values", other))
cond = getattr(cond, "values", cond)
# If the default broadcasting would go in the wrong direction, then
# explicitly reshape other instead
if getattr(other, "ndim", 0) >= 1:
if values.ndim - 1 == other.ndim and axis == 1:
other = other.reshape(tuple(other.shape + (1,)))
elif transpose and values.ndim == self.ndim - 1:
cond = cond.T
if not hasattr(cond, "shape"):
raise ValueError("where must have a condition that is ndarray like")
def where_func(cond, values, other):
if not (
(self.is_integer or self.is_bool)
and lib.is_float(other)
and np.isnan(other)
):
# np.where will cast integer array to floats in this case
if not self._can_hold_element(other):
raise TypeError
if lib.is_scalar(other) and isinstance(values, np.ndarray):
# convert datetime to datetime64, timedelta to timedelta64
other = convert_scalar(values, other)
# By the time we get here, we should have all Series/Index
# args extracted to ndarray
fastres = expressions.where(cond, values, other)
return fastres
if cond.ravel().all():
result = values
else:
# see if we can operate on the entire block, or need item-by-item
# or if we are a single block (ndim == 1)
try:
result = where_func(cond, values, other)
except TypeError:
# we cannot coerce, return a compat dtype
# we are explicitly ignoring errors
block = self.coerce_to_target_dtype(other)
blocks = block.where(
orig_other,
cond,
align=align,
errors=errors,
try_cast=try_cast,
axis=axis,
)
return self._maybe_downcast(blocks, "infer")
if self._can_hold_na or self.ndim == 1:
if transpose:
result = result.T
return [self.make_block(result)]
# might need to separate out blocks
axis = cond.ndim - 1
cond = cond.swapaxes(axis, 0)
mask = np.array([cond[i].all() for i in range(cond.shape[0])], dtype=bool)
result_blocks = []
for m in [mask, ~mask]:
if m.any():
taken = result.take(m.nonzero()[0], axis=axis)
r = maybe_downcast_numeric(taken, self.dtype)
nb = self.make_block(r.T, placement=self.mgr_locs[m])
result_blocks.append(nb)
return result_blocks
def equals(self, other) -> bool:
if self.dtype != other.dtype or self.shape != other.shape:
return False
return array_equivalent(self.values, other.values)
def _unstack(self, unstacker_func, new_columns, n_rows, fill_value):
"""Return a list of unstacked blocks of self
Parameters
----------
unstacker_func : callable
Partially applied unstacker.
new_columns : Index
All columns of the unstacked BlockManager.
n_rows : int
Only used in ExtensionBlock._unstack
fill_value : int
Only used in ExtensionBlock._unstack
Returns
-------
blocks : list of Block
New blocks of unstacked values.
mask : array_like of bool
The mask of columns of `blocks` we should keep.
"""
unstacker = unstacker_func(self.values.T)
new_items = unstacker.get_new_columns()
new_placement = new_columns.get_indexer(new_items)
new_values, mask = unstacker.get_new_values()
mask = mask.any(0)
new_values = new_values.T[mask]
new_placement = new_placement[mask]
blocks = [make_block(new_values, placement=new_placement)]
return blocks, mask
def quantile(self, qs, interpolation="linear", axis=0):
"""
compute the quantiles of the
Parameters
----------
qs: a scalar or list of the quantiles to be computed
interpolation: type of interpolation, default 'linear'
axis: axis to compute, default 0
Returns
-------
Block
"""
# We should always have ndim == 2 because Series dispatches to DataFrame
assert self.ndim == 2
values = self.get_values()
is_empty = values.shape[axis] == 0
orig_scalar = not is_list_like(qs)
if orig_scalar:
# make list-like, unpack later
qs = [qs]
if is_empty:
# create the array of na_values
# 2d len(values) * len(qs)
result = np.repeat(
np.array([self.fill_value] * len(qs)), len(values)
).reshape(len(values), len(qs))
else:
# asarray needed for Sparse, see GH#24600
mask = np.asarray(isna(values))
result = nanpercentile(
values,
np.array(qs) * 100,
axis=axis,
na_value=self.fill_value,
mask=mask,
ndim=values.ndim,
interpolation=interpolation,
)
result = np.array(result, copy=False)
result = result.T
if orig_scalar and not lib.is_scalar(result):
# result could be scalar in case with is_empty and self.ndim == 1
assert result.shape[-1] == 1, result.shape
result = result[..., 0]
result = lib.item_from_zerodim(result)
ndim = np.ndim(result)
return make_block(result, placement=np.arange(len(result)), ndim=ndim)
def _replace_coerce(
self, to_replace, value, inplace=True, regex=False, convert=False, mask=None
):
"""
Replace value corresponding to the given boolean array with another
value.
Parameters
----------
to_replace : object or pattern
Scalar to replace or regular expression to match.
value : object
Replacement object.
inplace : bool, default False
Perform inplace modification.
regex : bool, default False
If true, perform regular expression substitution.
convert : bool, default True
If true, try to coerce any object types to better types.
mask : array-like of bool, optional
True indicate corresponding element is ignored.
Returns
-------
A new block if there is anything to replace or the original block.
"""
if mask.any():
if not regex:
self = self.coerce_to_target_dtype(value)
return self.putmask(mask, value, inplace=inplace)
else:
return self._replace_single(
to_replace,
value,
inplace=inplace,
regex=regex,
convert=convert,
mask=mask,
)
return self
class NonConsolidatableMixIn:
""" hold methods for the nonconsolidatable blocks """
_can_consolidate = False
_verify_integrity = False
_validate_ndim = False
def __init__(self, values, placement, ndim=None):
"""Initialize a non-consolidatable block.
'ndim' may be inferred from 'placement'.
This will call continue to call __init__ for the other base
classes mixed in with this Mixin.
"""
# Placement must be converted to BlockPlacement so that we can check
# its length
if not isinstance(placement, libinternals.BlockPlacement):
placement = libinternals.BlockPlacement(placement)
# Maybe infer ndim from placement
if ndim is None:
if len(placement) != 1:
ndim = 1
else:
ndim = 2
super().__init__(values, placement, ndim=ndim)
@property
def shape(self):
if self.ndim == 1:
return ((len(self.values)),)
return (len(self.mgr_locs), len(self.values))
def iget(self, col):
if self.ndim == 2 and isinstance(col, tuple):
col, loc = col
if not com.is_null_slice(col) and col != 0:
raise IndexError(f"{self} only contains one item")
elif isinstance(col, slice):
if col != slice(None):
raise NotImplementedError(col)
return self.values[[loc]]
return self.values[loc]
else:
if col != 0:
raise IndexError(f"{self} only contains one item")
return self.values
def should_store(self, value):
return isinstance(value, self._holder)
def set(self, locs, values, check=False):
assert locs.tolist() == [0]
self.values = values
def putmask(self, mask, new, align=True, inplace=False, axis=0, transpose=False):
"""
putmask the data to the block; we must be a single block and not
generate other blocks
return the resulting block
Parameters
----------
mask : the condition to respect
new : a ndarray/object
align : boolean, perform alignment on other/cond, default is True
inplace : perform inplace modification, default is False
Returns
-------
a new block, the result of the putmask
"""
inplace = validate_bool_kwarg(inplace, "inplace")
# use block's copy logic.
# .values may be an Index which does shallow copy by default
new_values = self.values if inplace else self.copy().values
if isinstance(new, np.ndarray) and len(new) == len(mask):
new = new[mask]
mask = _safe_reshape(mask, new_values.shape)
new_values[mask] = new
return [self.make_block(values=new_values)]
def _get_unstack_items(self, unstacker, new_columns):
"""
Get the placement, values, and mask for a Block unstack.
This is shared between ObjectBlock and ExtensionBlock. They
differ in that ObjectBlock passes the values, while ExtensionBlock
passes the dummy ndarray of positions to be used by a take
later.
Parameters
----------
unstacker : pandas.core.reshape.reshape._Unstacker
new_columns : Index
All columns of the unstacked BlockManager.
Returns
-------
new_placement : ndarray[int]
The placement of the new columns in `new_columns`.
new_values : Union[ndarray, ExtensionArray]
The first return value from _Unstacker.get_new_values.
mask : ndarray[bool]
The second return value from _Unstacker.get_new_values.
"""
# shared with ExtensionBlock
new_items = unstacker.get_new_columns()
new_placement = new_columns.get_indexer(new_items)
new_values, mask = unstacker.get_new_values()
mask = mask.any(0)
return new_placement, new_values, mask
class ExtensionBlock(NonConsolidatableMixIn, Block):
"""Block for holding extension types.
Notes
-----
This holds all 3rd-party extension array types. It's also the immediate
parent class for our internal extension types' blocks, CategoricalBlock.
ExtensionArrays are limited to 1-D.
"""
is_extension = True
def __init__(self, values, placement, ndim=None):
values = self._maybe_coerce_values(values)
super().__init__(values, placement, ndim)
def _maybe_coerce_values(self, values):
"""
Unbox to an extension array.
This will unbox an ExtensionArray stored in an Index or Series.
ExtensionArrays pass through. No dtype coercion is done.
Parameters
----------
values : Index, Series, ExtensionArray
Returns
-------
ExtensionArray
"""
return extract_array(values)
@property
def _holder(self):
# For extension blocks, the holder is values-dependent.
return type(self.values)
@property
def fill_value(self):
# Used in reindex_indexer
return self.values.dtype.na_value
@property
def _can_hold_na(self):
# The default ExtensionArray._can_hold_na is True
return self._holder._can_hold_na
@property
def is_view(self):
"""Extension arrays are never treated as views."""
return False
@property
def is_numeric(self):
return self.values.dtype._is_numeric
def setitem(self, indexer, value):
"""Set the value inplace, returning a same-typed block.
This differs from Block.setitem by not allowing setitem to change
the dtype of the Block.
Parameters
----------
indexer : tuple, list-like, array-like, slice
The subset of self.values to set
value : object
The value being set
Returns
-------
Block
Notes
-----
`indexer` is a direct slice/positional indexer. `value` must
be a compatible shape.
"""
if isinstance(indexer, tuple):
# we are always 1-D
indexer = indexer[0]
check_setitem_lengths(indexer, value, self.values)
self.values[indexer] = value
return self
def get_values(self, dtype=None):
# ExtensionArrays must be iterable, so this works.
values = np.asarray(self.values)
if values.ndim == self.ndim - 1:
values = values.reshape((1,) + values.shape)
return values
def array_values(self) -> ExtensionArray:
return self.values
def to_dense(self):
return np.asarray(self.values)
def to_native_types(self, slicer=None, na_rep="nan", quoting=None, **kwargs):
"""override to use ExtensionArray astype for the conversion"""
values = self.values
if slicer is not None:
values = values[slicer]
mask = isna(values)
values = np.asarray(values.astype(object))
values[mask] = na_rep
# we are expected to return a 2-d ndarray
return values.reshape(1, len(values))
def take_nd(self, indexer, axis=0, new_mgr_locs=None, fill_tuple=None):
"""
Take values according to indexer and return them as a block.
"""
if fill_tuple is None:
fill_value = None
else:
fill_value = fill_tuple[0]
# axis doesn't matter; we are really a single-dim object
# but are passed the axis depending on the calling routing
# if its REALLY axis 0, then this will be a reindex and not a take
new_values = self.values.take(indexer, fill_value=fill_value, allow_fill=True)
# Called from three places in managers, all of which satisfy
# this assertion
assert not (self.ndim == 1 and new_mgr_locs is None)
if new_mgr_locs is None:
new_mgr_locs = self.mgr_locs
return self.make_block_same_class(new_values, new_mgr_locs)
def _can_hold_element(self, element: Any) -> bool:
# XXX: We may need to think about pushing this onto the array.
# We're doing the same as CategoricalBlock here.
return True
def _slice(self, slicer):
""" return a slice of my values """
# slice the category
# return same dims as we currently have
if isinstance(slicer, tuple) and len(slicer) == 2:
if not com.is_null_slice(slicer[0]):
raise AssertionError("invalid slicing for a 1-ndim categorical")
slicer = slicer[1]
return self.values[slicer]
def concat_same_type(self, to_concat, placement=None):
"""
Concatenate list of single blocks of the same type.
"""
values = self._holder._concat_same_type([blk.values for blk in to_concat])
placement = placement or slice(0, len(values), 1)
return self.make_block_same_class(values, ndim=self.ndim, placement=placement)
def fillna(self, value, limit=None, inplace=False, downcast=None):
values = self.values if inplace else self.values.copy()
values = values.fillna(value=value, limit=limit)
return [
self.make_block_same_class(
values=values, placement=self.mgr_locs, ndim=self.ndim
)
]
def interpolate(
self, method="pad", axis=0, inplace=False, limit=None, fill_value=None, **kwargs
):
values = self.values if inplace else self.values.copy()
return self.make_block_same_class(
values=values.fillna(value=fill_value, method=method, limit=limit),
placement=self.mgr_locs,
)
def diff(self, n: int, axis: int = 1) -> List["Block"]:
if axis == 1:
# we are by definition 1D.
axis = 0
return super().diff(n, axis)
def shift(
self,
periods: int,
axis: libinternals.BlockPlacement = 0,
fill_value: Any = None,
) -> List["ExtensionBlock"]:
"""
Shift the block by `periods`.
Dispatches to underlying ExtensionArray and re-boxes in an
ExtensionBlock.
"""
return [
self.make_block_same_class(
self.values.shift(periods=periods, fill_value=fill_value),
placement=self.mgr_locs,
ndim=self.ndim,
)
]
def where(
self,
other,
cond,
align=True,
errors="raise",
try_cast: bool = False,
axis: int = 0,
) -> List["Block"]:
if isinstance(other, ABCDataFrame):
# ExtensionArrays are 1-D, so if we get here then
# `other` should be a DataFrame with a single column.
assert other.shape[1] == 1
other = other.iloc[:, 0]
other = extract_array(other, extract_numpy=True)
if isinstance(cond, ABCDataFrame):
assert cond.shape[1] == 1
cond = cond.iloc[:, 0]
cond = extract_array(cond, extract_numpy=True)
if lib.is_scalar(other) and isna(other):
# The default `other` for Series / Frame is np.nan
# we want to replace that with the correct NA value
# for the type
other = self.dtype.na_value
if is_sparse(self.values):
# TODO(SparseArray.__setitem__): remove this if condition
# We need to re-infer the type of the data after doing the
# where, for cases where the subtypes don't match
dtype = None
else:
dtype = self.dtype
result = self.values.copy()
icond = ~cond
if lib.is_scalar(other):
set_other = other
else:
set_other = other[icond]
try:
result[icond] = set_other
except (NotImplementedError, TypeError):
# NotImplementedError for class not implementing `__setitem__`
# TypeError for SparseArray, which implements just to raise
# a TypeError
result = self._holder._from_sequence(
np.where(cond, self.values, other), dtype=dtype
)
return [self.make_block_same_class(result, placement=self.mgr_locs)]
@property
def _ftype(self):
return getattr(self.values, "_pandas_ftype", Block._ftype)
def _unstack(self, unstacker_func, new_columns, n_rows, fill_value):
# ExtensionArray-safe unstack.
# We override ObjectBlock._unstack, which unstacks directly on the
# values of the array. For EA-backed blocks, this would require
# converting to a 2-D ndarray of objects.
# Instead, we unstack an ndarray of integer positions, followed by
# a `take` on the actual values.
dummy_arr = np.arange(n_rows)
dummy_unstacker = functools.partial(unstacker_func, fill_value=-1)
unstacker = dummy_unstacker(dummy_arr)
new_placement, new_values, mask = self._get_unstack_items(
unstacker, new_columns
)
blocks = [
self.make_block_same_class(
self.values.take(indices, allow_fill=True, fill_value=fill_value),
[place],
)
for indices, place in zip(new_values.T, new_placement)
]
return blocks, mask
class ObjectValuesExtensionBlock(ExtensionBlock):
"""
Block providing backwards-compatibility for `.values`.
Used by PeriodArray and IntervalArray to ensure that
Series[T].values is an ndarray of objects.
"""
def external_values(self):
return self.values.astype(object)
class NumericBlock(Block):
__slots__ = ()
is_numeric = True
_can_hold_na = True
class FloatOrComplexBlock(NumericBlock):
__slots__ = ()
def equals(self, other) -> bool:
if self.dtype != other.dtype or self.shape != other.shape:
return False
left, right = self.values, other.values
return ((left == right) | (np.isnan(left) & np.isnan(right))).all()
class FloatBlock(FloatOrComplexBlock):
__slots__ = ()
is_float = True
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return issubclass(tipo.type, (np.floating, np.integer)) and not issubclass(
tipo.type, (np.datetime64, np.timedelta64)
)
return isinstance(
element, (float, int, np.floating, np.int_)
) and not isinstance(
element,
(bool, np.bool_, datetime, timedelta, np.datetime64, np.timedelta64),
)
def to_native_types(
self,
slicer=None,
na_rep="",
float_format=None,
decimal=".",
quoting=None,
**kwargs,
):
""" convert to our native types format, slicing if desired """
values = self.values
if slicer is not None:
values = values[:, slicer]
# see gh-13418: no special formatting is desired at the
# output (important for appropriate 'quoting' behaviour),
# so do not pass it through the FloatArrayFormatter
if float_format is None and decimal == ".":
mask = isna(values)
if not quoting:
values = values.astype(str)
else:
values = np.array(values, dtype="object")
values[mask] = na_rep
return values
from pandas.io.formats.format import FloatArrayFormatter
formatter = FloatArrayFormatter(
values,
na_rep=na_rep,
float_format=float_format,
decimal=decimal,
quoting=quoting,
fixed_width=False,
)
return formatter.get_result_as_array()
def should_store(self, value):
# when inserting a column should not coerce integers to floats
# unnecessarily
return issubclass(value.dtype.type, np.floating) and value.dtype == self.dtype
class ComplexBlock(FloatOrComplexBlock):
__slots__ = ()
is_complex = True
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return issubclass(tipo.type, (np.floating, np.integer, np.complexfloating))
return isinstance(
element, (float, int, complex, np.float_, np.int_)
) and not isinstance(element, (bool, np.bool_))
def should_store(self, value):
return issubclass(value.dtype.type, np.complexfloating)
class IntBlock(NumericBlock):
__slots__ = ()
is_integer = True
_can_hold_na = False
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return (
issubclass(tipo.type, np.integer)
and not issubclass(tipo.type, (np.datetime64, np.timedelta64))
and self.dtype.itemsize >= tipo.itemsize
)
return is_integer(element)
def should_store(self, value):
return is_integer_dtype(value) and value.dtype == self.dtype
class DatetimeLikeBlockMixin:
"""Mixin class for DatetimeBlock, DatetimeTZBlock, and TimedeltaBlock."""
@property
def _holder(self):
return DatetimeArray
@property
def fill_value(self):
return np.datetime64("NaT", "ns")
def get_values(self, dtype=None):
"""
return object dtype as boxed values, such as Timestamps/Timedelta
"""
if is_object_dtype(dtype):
values = self.values.ravel()
result = self._holder(values).astype(object)
return result.reshape(self.values.shape)
return self.values
def internal_values(self):
# Override to return DatetimeArray and TimedeltaArray
return self.array_values()
def iget(self, key):
# GH#31649 we need to wrap scalars in Timestamp/Timedelta
# TODO: this can be removed if we ever have 2D EA
result = super().iget(key)
if isinstance(result, np.datetime64):
result = Timestamp(result)
elif isinstance(result, np.timedelta64):
result = Timedelta(result)
return result
class DatetimeBlock(DatetimeLikeBlockMixin, Block):
__slots__ = ()
is_datetime = True
def __init__(self, values, placement, ndim=None):
values = self._maybe_coerce_values(values)
super().__init__(values, placement=placement, ndim=ndim)
@property
def _can_hold_na(self):
return True
def _maybe_coerce_values(self, values):
"""
Input validation for values passed to __init__. Ensure that
we have datetime64ns, coercing if necessary.
Parameters
----------
values : array-like
Must be convertible to datetime64
Returns
-------
values : ndarray[datetime64ns]
Overridden by DatetimeTZBlock.
"""
if values.dtype != _NS_DTYPE:
values = conversion.ensure_datetime64ns(values)
if isinstance(values, DatetimeArray):
values = values._data
assert isinstance(values, np.ndarray), type(values)
return values
def astype(self, dtype, copy: bool = False, errors: str = "raise"):
"""
these automatically copy, so copy=True has no effect
raise on an except if raise == True
"""
dtype = pandas_dtype(dtype)
# if we are passed a datetime64[ns, tz]
if is_datetime64tz_dtype(dtype):
values = self.values
if getattr(values, "tz", None) is None:
values = DatetimeArray(values).tz_localize("UTC")
values = values.tz_convert(dtype.tz)
return self.make_block(values)
# delegate
return super().astype(dtype=dtype, copy=copy, errors=errors)
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
if self.is_datetimetz:
# require exact match, since non-nano does not exist
return is_dtype_equal(tipo, self.dtype) or is_valid_nat_for_dtype(
element, self.dtype
)
# GH#27419 if we get a non-nano datetime64 object
return is_datetime64_dtype(tipo)
elif element is NaT:
return True
elif isinstance(element, datetime):
if self.is_datetimetz:
return tz_compare(element.tzinfo, self.dtype.tz)
return element.tzinfo is None
return is_valid_nat_for_dtype(element, self.dtype)
def to_native_types(
self, slicer=None, na_rep=None, date_format=None, quoting=None, **kwargs
):
""" convert to our native types format, slicing if desired """
values = self.values
i8values = self.values.view("i8")
if slicer is not None:
values = values[..., slicer]
i8values = i8values[..., slicer]
from pandas.io.formats.format import _get_format_datetime64_from_values
fmt = _get_format_datetime64_from_values(values, date_format)
result = tslib.format_array_from_datetime(
i8values.ravel(),
tz=getattr(self.values, "tz", None),
format=fmt,
na_rep=na_rep,
).reshape(i8values.shape)
return np.atleast_2d(result)
def should_store(self, value):
return (
issubclass(value.dtype.type, np.datetime64)
and not is_datetime64tz_dtype(value)
and not is_extension_array_dtype(value)
)
def set(self, locs, values):
"""
Modify Block in-place with new item value
Returns
-------
None
"""
values = conversion.ensure_datetime64ns(values, copy=False)
self.values[locs] = values
def external_values(self):
return np.asarray(self.values.astype("datetime64[ns]", copy=False))
def array_values(self) -> ExtensionArray:
return DatetimeArray._simple_new(self.values)
class DatetimeTZBlock(ExtensionBlock, DatetimeBlock):
""" implement a datetime64 block with a tz attribute """
__slots__ = ()
is_datetimetz = True
is_extension = True
internal_values = Block.internal_values
_can_hold_element = DatetimeBlock._can_hold_element
to_native_types = DatetimeBlock.to_native_types
fill_value = np.datetime64("NaT", "ns")
@property
def _holder(self):
return DatetimeArray
def _maybe_coerce_values(self, values):
"""Input validation for values passed to __init__. Ensure that
we have datetime64TZ, coercing if necessary.
Parameters
----------
values : array-like
Must be convertible to datetime64
Returns
-------
values : DatetimeArray
"""
if not isinstance(values, self._holder):
values = self._holder(values)
if values.tz is None:
raise ValueError("cannot create a DatetimeTZBlock without a tz")
return values
@property
def is_view(self):
""" return a boolean if I am possibly a view """
# check the ndarray values of the DatetimeIndex values
return self.values._data.base is not None
def get_values(self, dtype=None):
"""
Returns an ndarray of values.
Parameters
----------
dtype : np.dtype
Only `object`-like dtypes are respected here (not sure
why).
Returns
-------
values : ndarray
When ``dtype=object``, then and object-dtype ndarray of
boxed values is returned. Otherwise, an M8[ns] ndarray
is returned.
DatetimeArray is always 1-d. ``get_values`` will reshape
the return value to be the same dimensionality as the
block.
"""
values = self.values
if is_object_dtype(dtype):
values = values.astype(object)
values = np.asarray(values)
if self.ndim == 2:
# Ensure that our shape is correct for DataFrame.
# ExtensionArrays are always 1-D, even in a DataFrame when
# the analogous NumPy-backed column would be a 2-D ndarray.
values = values.reshape(1, -1)
return values
def to_dense(self):
# we request M8[ns] dtype here, even though it discards tzinfo,
# as lots of code (e.g. anything using values_from_object)
# expects that behavior.
return np.asarray(self.values, dtype=_NS_DTYPE)
def _slice(self, slicer):
""" return a slice of my values """
if isinstance(slicer, tuple):
col, loc = slicer
if not com.is_null_slice(col) and col != 0:
raise IndexError(f"{self} only contains one item")
return self.values[loc]
return self.values[slicer]
def diff(self, n: int, axis: int = 0) -> List["Block"]:
"""
1st discrete difference.
Parameters
----------
n : int
Number of periods to diff.
axis : int, default 0
Axis to diff upon.
Returns
-------
A list with a new TimeDeltaBlock.
Notes
-----
The arguments here are mimicking shift so they are called correctly
by apply.
"""
if axis == 0:
# Cannot currently calculate diff across multiple blocks since this
# function is invoked via apply
raise NotImplementedError
new_values = (self.values - self.shift(n, axis=axis)[0].values).asi8
# Reshape the new_values like how algos.diff does for timedelta data
new_values = new_values.reshape(1, len(new_values))
new_values = new_values.astype("timedelta64[ns]")
return [TimeDeltaBlock(new_values, placement=self.mgr_locs.indexer)]
def concat_same_type(self, to_concat, placement=None):
# need to handle concat([tz1, tz2]) here, since DatetimeArray
# only handles cases where all the tzs are the same.
# Instead of placing the condition here, it could also go into the
# is_uniform_join_units check, but I'm not sure what is better.
if len({x.dtype for x in to_concat}) > 1:
values = concat_datetime([x.values for x in to_concat])
placement = placement or slice(0, len(values), 1)
if self.ndim > 1:
values = np.atleast_2d(values)
return ObjectBlock(values, ndim=self.ndim, placement=placement)
return super().concat_same_type(to_concat, placement)
def fillna(self, value, limit=None, inplace=False, downcast=None):
# We support filling a DatetimeTZ with a `value` whose timezone
# is different by coercing to object.
if self._can_hold_element(value):
return super().fillna(value, limit, inplace, downcast)
# different timezones, or a non-tz
return self.astype(object).fillna(
value, limit=limit, inplace=inplace, downcast=downcast
)
def setitem(self, indexer, value):
# https://github.com/pandas-dev/pandas/issues/24020
# Need a dedicated setitem until #24020 (type promotion in setitem
# for extension arrays) is designed and implemented.
if self._can_hold_element(value) or (
isinstance(indexer, np.ndarray) and indexer.size == 0
):
return super().setitem(indexer, value)
obj_vals = self.values.astype(object)
newb = make_block(
obj_vals, placement=self.mgr_locs, klass=ObjectBlock, ndim=self.ndim
)
return newb.setitem(indexer, value)
def equals(self, other) -> bool:
# override for significant performance improvement
if self.dtype != other.dtype or self.shape != other.shape:
return False
return (self.values.view("i8") == other.values.view("i8")).all()
def quantile(self, qs, interpolation="linear", axis=0):
naive = self.values.view("M8[ns]")
# kludge for 2D block with 1D values
naive = naive.reshape(self.shape)
blk = self.make_block(naive)
res_blk = blk.quantile(qs, interpolation=interpolation, axis=axis)
# ravel is kludge for 2D block with 1D values, assumes column-like
aware = self._holder(res_blk.values.ravel(), dtype=self.dtype)
return self.make_block_same_class(aware, ndim=res_blk.ndim)
class TimeDeltaBlock(DatetimeLikeBlockMixin, IntBlock):
__slots__ = ()
is_timedelta = True
_can_hold_na = True
is_numeric = False
fill_value = np.timedelta64("NaT", "ns")
def __init__(self, values, placement, ndim=None):
if values.dtype != _TD_DTYPE:
values = conversion.ensure_timedelta64ns(values)
if isinstance(values, TimedeltaArray):
values = values._data
assert isinstance(values, np.ndarray), type(values)
super().__init__(values, placement=placement, ndim=ndim)
@property
def _holder(self):
return TimedeltaArray
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return issubclass(tipo.type, np.timedelta64)
elif element is NaT:
return True
elif isinstance(element, (timedelta, np.timedelta64)):
return True
return is_valid_nat_for_dtype(element, self.dtype)
def fillna(self, value, **kwargs):
# allow filling with integers to be
# interpreted as nanoseconds
if is_integer(value):
# Deprecation GH#24694, GH#19233
raise TypeError(
"Passing integers to fillna for timedelta64[ns] dtype is no "
"longer supported. To obtain the old behavior, pass "
"`pd.Timedelta(seconds=n)` instead."
)
return super().fillna(value, **kwargs)
def should_store(self, value):
return issubclass(
value.dtype.type, np.timedelta64
) and not is_extension_array_dtype(value)
def to_native_types(self, slicer=None, na_rep=None, quoting=None, **kwargs):
""" convert to our native types format, slicing if desired """
values = self.values
if slicer is not None:
values = values[:, slicer]
mask = isna(values)
rvalues = np.empty(values.shape, dtype=object)
if na_rep is None:
na_rep = "NaT"
rvalues[mask] = na_rep
imask = (~mask).ravel()
# FIXME:
# should use the formats.format.Timedelta64Formatter here
# to figure what format to pass to the Timedelta
# e.g. to not show the decimals say
rvalues.flat[imask] = np.array(
[Timedelta(val)._repr_base(format="all") for val in values.ravel()[imask]],
dtype=object,
)
return rvalues
def external_values(self):
return np.asarray(self.values.astype("timedelta64[ns]", copy=False))
def array_values(self) -> ExtensionArray:
return TimedeltaArray._simple_new(self.values)
class BoolBlock(NumericBlock):
__slots__ = ()
is_bool = True
_can_hold_na = False
def _can_hold_element(self, element: Any) -> bool:
tipo = maybe_infer_dtype_type(element)
if tipo is not None:
return issubclass(tipo.type, np.bool_)
return isinstance(element, (bool, np.bool_))
def should_store(self, value):
return issubclass(value.dtype.type, np.bool_) and not is_extension_array_dtype(
value
)
def replace(
self, to_replace, value, inplace=False, filter=None, regex=False, convert=True
):
inplace = validate_bool_kwarg(inplace, "inplace")
to_replace_values = np.atleast_1d(to_replace)
if not np.can_cast(to_replace_values, bool):
return self
return super().replace(
to_replace,
value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
class ObjectBlock(Block):
__slots__ = ()
is_object = True
_can_hold_na = True
def __init__(self, values, placement=None, ndim=2):
if issubclass(values.dtype.type, str):
values = np.array(values, dtype=object)
super().__init__(values, ndim=ndim, placement=placement)
@property
def is_bool(self):
""" we can be a bool if we have only bool values but are of type
object
"""
return lib.is_bool_array(self.values.ravel())
def convert(
self,
copy: bool = True,
datetime: bool = True,
numeric: bool = True,
timedelta: bool = True,
coerce: bool = False,
):
""" attempt to coerce any object types to better types return a copy of
the block (if copy = True) by definition we ARE an ObjectBlock!!!!!
can return multiple blocks!
"""
# operate column-by-column
def f(mask, val, idx):
shape = val.shape
values = soft_convert_objects(
val.ravel(),
datetime=datetime,
numeric=numeric,
timedelta=timedelta,
coerce=coerce,
copy=copy,
)
if isinstance(values, np.ndarray):
# TODO: allow EA once reshape is supported
values = values.reshape(shape)
values = _block_shape(values, ndim=self.ndim)
return values
if self.ndim == 2:
blocks = self.split_and_operate(None, f, False)
else:
values = f(None, self.values.ravel(), None)
blocks = [make_block(values, ndim=self.ndim, placement=self.mgr_locs)]
return blocks
def _maybe_downcast(self, blocks: List["Block"], downcast=None) -> List["Block"]:
if downcast is not None:
return blocks
# split and convert the blocks
return _extend_blocks([b.convert(datetime=True, numeric=False) for b in blocks])
def _can_hold_element(self, element: Any) -> bool:
return True
def should_store(self, value):
return not (
issubclass(
value.dtype.type,
(np.integer, np.floating, np.complexfloating, np.datetime64, np.bool_),
)
or is_extension_array_dtype(value)
)
def replace(
self, to_replace, value, inplace=False, filter=None, regex=False, convert=True
):
to_rep_is_list = is_list_like(to_replace)
value_is_list = is_list_like(value)
both_lists = to_rep_is_list and value_is_list
either_list = to_rep_is_list or value_is_list
result_blocks = []
blocks = [self]
if not either_list and is_re(to_replace):
return self._replace_single(
to_replace,
value,
inplace=inplace,
filter=filter,
regex=True,
convert=convert,
)
elif not (either_list or regex):
return super().replace(
to_replace,
value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
elif both_lists:
for to_rep, v in zip(to_replace, value):
result_blocks = []
for b in blocks:
result = b._replace_single(
to_rep,
v,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
result_blocks = _extend_blocks(result, result_blocks)
blocks = result_blocks
return result_blocks
elif to_rep_is_list and regex:
for to_rep in to_replace:
result_blocks = []
for b in blocks:
result = b._replace_single(
to_rep,
value,
inplace=inplace,
filter=filter,
regex=regex,
convert=convert,
)
result_blocks = _extend_blocks(result, result_blocks)
blocks = result_blocks
return result_blocks
return self._replace_single(
to_replace,
value,
inplace=inplace,
filter=filter,
convert=convert,
regex=regex,
)
def _replace_single(
self,
to_replace,
value,
inplace=False,
filter=None,
regex=False,
convert=True,
mask=None,
):
"""
Replace elements by the given value.
Parameters
----------
to_replace : object or pattern
Scalar to replace or regular expression to match.
value : object
Replacement object.
inplace : bool, default False
Perform inplace modification.
filter : list, optional
regex : bool, default False
If true, perform regular expression substitution.
convert : bool, default True
If true, try to coerce any object types to better types.
mask : array-like of bool, optional
True indicate corresponding element is ignored.
Returns
-------
a new block, the result after replacing
"""
inplace = validate_bool_kwarg(inplace, "inplace")
# to_replace is regex compilable
to_rep_re = regex and is_re_compilable(to_replace)
# regex is regex compilable
regex_re = is_re_compilable(regex)
# only one will survive
if to_rep_re and regex_re:
raise AssertionError(
"only one of to_replace and regex can be regex compilable"
)
# if regex was passed as something that can be a regex (rather than a
# boolean)
if regex_re:
to_replace = regex
regex = regex_re or to_rep_re
# try to get the pattern attribute (compiled re) or it's a string
if is_re(to_replace):
pattern = to_replace.pattern
else:
pattern = to_replace
# if the pattern is not empty and to_replace is either a string or a
# regex
if regex and pattern:
rx = re.compile(to_replace)
else:
# if the thing to replace is not a string or compiled regex call
# the superclass method -> to_replace is some kind of object
return super().replace(
to_replace, value, inplace=inplace, filter=filter, regex=regex
)
new_values = self.values if inplace else self.values.copy()
# deal with replacing values with objects (strings) that match but
# whose replacement is not a string (numeric, nan, object)
if isna(value) or not isinstance(value, str):
def re_replacer(s):
if is_re(rx) and isinstance(s, str):
return value if rx.search(s) is not None else s
else:
return s
else:
# value is guaranteed to be a string here, s can be either a string
# or null if it's null it gets returned
def re_replacer(s):
if is_re(rx) and isinstance(s, str):
return rx.sub(value, s)
else:
return s
f = np.vectorize(re_replacer, otypes=[self.dtype])
if filter is None:
filt = slice(None)
else:
filt = self.mgr_locs.isin(filter).nonzero()[0]
if mask is None:
new_values[filt] = f(new_values[filt])
else:
new_values[filt][mask] = f(new_values[filt][mask])
# convert
block = self.make_block(new_values)
if convert:
block = block.convert(numeric=False)
return block
def _replace_coerce(
self, to_replace, value, inplace=True, regex=False, convert=False, mask=None
):
"""
Replace value corresponding to the given boolean array with another
value.
Parameters
----------
to_replace : object or pattern
Scalar to replace or regular expression to match.
value : object
Replacement object.
inplace : bool, default False
Perform inplace modification.
regex : bool, default False
If true, perform regular expression substitution.
convert : bool, default True
If true, try to coerce any object types to better types.
mask : array-like of bool, optional
True indicate corresponding element is ignored.
Returns
-------
A new block if there is anything to replace or the original block.
"""
if mask.any():
block = super()._replace_coerce(
to_replace=to_replace,
value=value,
inplace=inplace,
regex=regex,
convert=convert,
mask=mask,
)
if convert:
block = [b.convert(numeric=False, copy=True) for b in block]
return block
if convert:
return [self.convert(numeric=False, copy=True)]
return self
class CategoricalBlock(ExtensionBlock):
__slots__ = ()
is_categorical = True
_verify_integrity = True
_can_hold_na = True
_concatenator = staticmethod(concat_categorical)
def __init__(self, values, placement, ndim=None):
# coerce to categorical if we can
values = extract_array(values)
assert isinstance(values, Categorical), type(values)
super().__init__(values, placement=placement, ndim=ndim)
@property
def _holder(self):
return Categorical
@property
def array_dtype(self):
""" the dtype to return if I want to construct this block as an
array
"""
return np.object_
def to_dense(self):
# Categorical.get_values returns a DatetimeIndex for datetime
# categories, so we can't simply use `np.asarray(self.values)` like
# other types.
return self.values._internal_get_values()
def to_native_types(self, slicer=None, na_rep="", quoting=None, **kwargs):
""" convert to our native types format, slicing if desired """
values = self.values
if slicer is not None:
# Categorical is always one dimension
values = values[slicer]
mask = isna(values)
values = np.array(values, dtype="object")
values[mask] = na_rep
# we are expected to return a 2-d ndarray
return values.reshape(1, len(values))
def concat_same_type(self, to_concat, placement=None):
"""
Concatenate list of single blocks of the same type.
Note that this CategoricalBlock._concat_same_type *may* not
return a CategoricalBlock. When the categories in `to_concat`
differ, this will return an object ndarray.
If / when we decide we don't like that behavior:
1. Change Categorical._concat_same_type to use union_categoricals
2. Delete this method.
"""
values = self._concatenator(
[blk.values for blk in to_concat], axis=self.ndim - 1
)
# not using self.make_block_same_class as values can be object dtype
return make_block(
values, placement=placement or slice(0, len(values), 1), ndim=self.ndim
)
def replace(
self,
to_replace,
value,
inplace: bool = False,
filter=None,
regex: bool = False,
convert: bool = True,
):
inplace = validate_bool_kwarg(inplace, "inplace")
result = self if inplace else self.copy()
if filter is None: # replace was called on a series
result.values.replace(to_replace, value, inplace=True)
if convert:
return result.convert(numeric=False, copy=not inplace)
else:
return result
else: # replace was called on a DataFrame
if not isna(value):
result.values.add_categories(value, inplace=True)
return super(CategoricalBlock, result).replace(
to_replace, value, inplace, filter, regex, convert
)
# -----------------------------------------------------------------
# Constructor Helpers
def get_block_type(values, dtype=None):
"""
Find the appropriate Block subclass to use for the given values and dtype.
Parameters
----------
values : ndarray-like
dtype : numpy or pandas dtype
Returns
-------
cls : class, subclass of Block
"""
dtype = dtype or values.dtype
vtype = dtype.type
if is_sparse(dtype):
# Need this first(ish) so that Sparse[datetime] is sparse
cls = ExtensionBlock
elif is_categorical(values):
cls = CategoricalBlock
elif issubclass(vtype, np.datetime64):
assert not is_datetime64tz_dtype(values)
cls = DatetimeBlock
elif is_datetime64tz_dtype(values):
cls = DatetimeTZBlock
elif is_interval_dtype(dtype) or is_period_dtype(dtype):
cls = ObjectValuesExtensionBlock
elif is_extension_array_dtype(values):
cls = ExtensionBlock
elif issubclass(vtype, np.floating):
cls = FloatBlock
elif issubclass(vtype, np.timedelta64):
assert issubclass(vtype, np.integer)
cls = TimeDeltaBlock
elif issubclass(vtype, np.complexfloating):
cls = ComplexBlock
elif issubclass(vtype, np.integer):
cls = IntBlock
elif dtype == np.bool_:
cls = BoolBlock
else:
cls = ObjectBlock
return cls
def make_block(values, placement, klass=None, ndim=None, dtype=None):
# Ensure that we don't allow PandasArray / PandasDtype in internals.
# For now, blocks should be backed by ndarrays when possible.
if isinstance(values, ABCPandasArray):
values = values.to_numpy()
if ndim and ndim > 1:
values = np.atleast_2d(values)
if isinstance(dtype, PandasDtype):
dtype = dtype.numpy_dtype
if klass is None:
dtype = dtype or values.dtype
klass = get_block_type(values, dtype)
elif klass is DatetimeTZBlock and not is_datetime64tz_dtype(values):
# TODO: This is no longer hit internally; does it need to be retained
# for e.g. pyarrow?
values = DatetimeArray._simple_new(values, dtype=dtype)
return klass(values, ndim=ndim, placement=placement)
# -----------------------------------------------------------------
def _extend_blocks(result, blocks=None):
""" return a new extended blocks, given the result """
if blocks is None:
blocks = []
if isinstance(result, list):
for r in result:
if isinstance(r, list):
blocks.extend(r)
else:
blocks.append(r)
else:
assert isinstance(result, Block), type(result)
blocks.append(result)
return blocks
def _block_shape(values, ndim=1, shape=None):
""" guarantee the shape of the values to be at least 1 d """
if values.ndim < ndim:
if shape is None:
shape = values.shape
if not is_extension_array_dtype(values):
# TODO: https://github.com/pandas-dev/pandas/issues/23023
# block.shape is incorrect for "2D" ExtensionArrays
# We can't, and don't need to, reshape.
values = values.reshape(tuple((1,) + shape))
return values
def _merge_blocks(blocks, dtype=None, _can_consolidate=True):
if len(blocks) == 1:
return blocks[0]
if _can_consolidate:
if dtype is None:
if len({b.dtype for b in blocks}) != 1:
raise AssertionError("_merge_blocks are invalid!")
# FIXME: optimization potential in case all mgrs contain slices and
# combination of those slices is a slice, too.
new_mgr_locs = np.concatenate([b.mgr_locs.as_array for b in blocks])
new_values = np.vstack([b.values for b in blocks])
argsort = np.argsort(new_mgr_locs)
new_values = new_values[argsort]
new_mgr_locs = new_mgr_locs[argsort]
return make_block(new_values, placement=new_mgr_locs)
# no merge
return blocks
def _safe_reshape(arr, new_shape):
"""
If possible, reshape `arr` to have shape `new_shape`,
with a couple of exceptions (see gh-13012):
1) If `arr` is a ExtensionArray or Index, `arr` will be
returned as is.
2) If `arr` is a Series, the `_values` attribute will
be reshaped and returned.
Parameters
----------
arr : array-like, object to be reshaped
new_shape : int or tuple of ints, the new shape
"""
if isinstance(arr, ABCSeries):
arr = arr._values
if not isinstance(arr, ABCExtensionArray):
arr = arr.reshape(new_shape)
return arr
def _putmask_smart(v, mask, n):
"""
Return a new ndarray, try to preserve dtype if possible.
Parameters
----------
v : `values`, updated in-place (array like)
mask : np.ndarray
Applies to both sides (array like).
n : `new values` either scalar or an array like aligned with `values`
Returns
-------
values : ndarray with updated values
this *may* be a copy of the original
See Also
--------
ndarray.putmask
"""
# we cannot use np.asarray() here as we cannot have conversions
# that numpy does when numeric are mixed with strings
# n should be the length of the mask or a scalar here
if not is_list_like(n):
n = np.repeat(n, len(mask))
# see if we are only masking values that if putted
# will work in the current dtype
try:
nn = n[mask]
except TypeError:
# TypeError: only integer scalar arrays can be converted to a scalar index
pass
else:
# make sure that we have a nullable type
# if we have nulls
if not _isna_compat(v, nn[0]):
pass
elif not (is_float_dtype(nn.dtype) or is_integer_dtype(nn.dtype)):
# only compare integers/floats
pass
elif not (is_float_dtype(v.dtype) or is_integer_dtype(v.dtype)):
# only compare integers/floats
pass
else:
# we ignore ComplexWarning here
with warnings.catch_warnings(record=True):
warnings.simplefilter("ignore", np.ComplexWarning)
nn_at = nn.astype(v.dtype)
comp = nn == nn_at
if is_list_like(comp) and comp.all():
nv = v.copy()
nv[mask] = nn_at
return nv
n = np.asarray(n)
def _putmask_preserve(nv, n):
try:
nv[mask] = n[mask]
except (IndexError, ValueError):
nv[mask] = n
return nv
# preserves dtype if possible
if v.dtype.kind == n.dtype.kind:
return _putmask_preserve(v, n)
# change the dtype if needed
dtype, _ = maybe_promote(n.dtype)
if is_extension_array_dtype(v.dtype) and is_object_dtype(dtype):
v = v._internal_get_values(dtype)
else:
v = v.astype(dtype)
return _putmask_preserve(v, n)
| BugsInPy/BugsInPy/temp/projects/pandas/bug-67-fixed/pandas/pandas/core/internals/blocks.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-67-buggy/pandas/pandas/core/internals/blocks.py |
pandas-bug-110 | from datetime import datetime
import operator
from textwrap import dedent
from typing import FrozenSet, Union
import warnings
import numpy as np
from pandas._libs import algos as libalgos, index as libindex, lib
import pandas._libs.join as libjoin
from pandas._libs.lib import is_datetime_array
from pandas._libs.tslibs import OutOfBoundsDatetime, Timestamp
from pandas._libs.tslibs.period import IncompatibleFrequency
from pandas._libs.tslibs.timezones import tz_compare
from pandas.compat import set_function_name
from pandas.compat.numpy import function as nv
from pandas.util._decorators import Appender, Substitution, cache_readonly
from pandas.core.dtypes import concat as _concat
from pandas.core.dtypes.cast import maybe_cast_to_integer_array
from pandas.core.dtypes.common import (
ensure_categorical,
ensure_int64,
ensure_object,
ensure_platform_int,
is_bool,
is_bool_dtype,
is_categorical,
is_categorical_dtype,
is_datetime64_any_dtype,
is_datetime64tz_dtype,
is_dtype_equal,
is_extension_array_dtype,
is_float,
is_float_dtype,
is_hashable,
is_integer,
is_integer_dtype,
is_interval_dtype,
is_iterator,
is_list_like,
is_object_dtype,
is_period_dtype,
is_scalar,
is_signed_integer_dtype,
is_timedelta64_dtype,
is_unsigned_integer_dtype,
)
from pandas.core.dtypes.concat import concat_compat
from pandas.core.dtypes.generic import (
ABCCategorical,
ABCDataFrame,
ABCDatetimeArray,
ABCDatetimeIndex,
ABCIndexClass,
ABCIntervalIndex,
ABCMultiIndex,
ABCPandasArray,
ABCPeriodIndex,
ABCSeries,
ABCTimedeltaIndex,
)
from pandas.core.dtypes.missing import array_equivalent, isna
from pandas.core import ops
from pandas.core.accessor import CachedAccessor
import pandas.core.algorithms as algos
from pandas.core.arrays import ExtensionArray
from pandas.core.base import IndexOpsMixin, PandasObject
import pandas.core.common as com
from pandas.core.construction import extract_array
from pandas.core.indexers import maybe_convert_indices
from pandas.core.indexes.frozen import FrozenList
import pandas.core.missing as missing
from pandas.core.ops import get_op_result_name
from pandas.core.ops.invalid import make_invalid_op
from pandas.core.strings import StringMethods
from pandas.io.formats.printing import (
default_pprint,
format_object_attrs,
format_object_summary,
pprint_thing,
)
__all__ = ["Index"]
_unsortable_types = frozenset(("mixed", "mixed-integer"))
_index_doc_kwargs = dict(
klass="Index",
inplace="",
target_klass="Index",
raises_section="",
unique="Index",
duplicated="np.ndarray",
)
_index_shared_docs = dict()
def _make_comparison_op(op, cls):
def cmp_method(self, other):
if isinstance(other, (np.ndarray, Index, ABCSeries, ExtensionArray)):
if other.ndim > 0 and len(self) != len(other):
raise ValueError("Lengths must match to compare")
if is_object_dtype(self) and isinstance(other, ABCCategorical):
left = type(other)(self._values, dtype=other.dtype)
return op(left, other)
elif is_object_dtype(self) and not isinstance(self, ABCMultiIndex):
# don't pass MultiIndex
with np.errstate(all="ignore"):
result = ops.comp_method_OBJECT_ARRAY(op, self.values, other)
else:
with np.errstate(all="ignore"):
result = op(self.values, np.asarray(other))
if is_bool_dtype(result):
return result
return ops.invalid_comparison(self, other, op)
name = f"__{op.__name__}__"
return set_function_name(cmp_method, name, cls)
def _make_arithmetic_op(op, cls):
def index_arithmetic_method(self, other):
if isinstance(other, (ABCSeries, ABCDataFrame, ABCTimedeltaIndex)):
return NotImplemented
from pandas import Series
result = op(Series(self), other)
if isinstance(result, tuple):
return (Index(result[0]), Index(result[1]))
return Index(result)
name = f"__{op.__name__}__"
# TODO: docstring?
return set_function_name(index_arithmetic_method, name, cls)
class InvalidIndexError(Exception):
pass
_o_dtype = np.dtype(object)
_Identity = object
def _new_Index(cls, d):
"""
This is called upon unpickling, rather than the default which doesn't
have arguments and breaks __new__.
"""
# required for backward compat, because PI can't be instantiated with
# ordinals through __new__ GH #13277
if issubclass(cls, ABCPeriodIndex):
from pandas.core.indexes.period import _new_PeriodIndex
return _new_PeriodIndex(cls, **d)
if issubclass(cls, ABCMultiIndex):
if "labels" in d and "codes" not in d:
# GH#23752 "labels" kwarg has been replaced with "codes"
d["codes"] = d.pop("labels")
return cls.__new__(cls, **d)
class Index(IndexOpsMixin, PandasObject):
"""
Immutable ndarray implementing an ordered, sliceable set. The basic object
storing axis labels for all pandas objects.
Parameters
----------
data : array-like (1-dimensional)
dtype : NumPy dtype (default: object)
If dtype is None, we find the dtype that best fits the data.
If an actual dtype is provided, we coerce to that dtype if it's safe.
Otherwise, an error will be raised.
copy : bool
Make a copy of input ndarray.
name : object
Name to be stored in the index.
tupleize_cols : bool (default: True)
When True, attempt to create a MultiIndex if possible.
See Also
--------
RangeIndex : Index implementing a monotonic integer range.
CategoricalIndex : Index of :class:`Categorical` s.
MultiIndex : A multi-level, or hierarchical, Index.
IntervalIndex : An Index of :class:`Interval` s.
DatetimeIndex, TimedeltaIndex, PeriodIndex
Int64Index, UInt64Index, Float64Index
Notes
-----
An Index instance can **only** contain hashable objects
Examples
--------
>>> pd.Index([1, 2, 3])
Int64Index([1, 2, 3], dtype='int64')
>>> pd.Index(list('abc'))
Index(['a', 'b', 'c'], dtype='object')
"""
# tolist is not actually deprecated, just suppressed in the __dir__
_deprecations: FrozenSet[str] = (
PandasObject._deprecations
| IndexOpsMixin._deprecations
| frozenset(["contains", "set_value"])
)
# To hand over control to subclasses
_join_precedence = 1
# Cython methods; see github.com/cython/cython/issues/2647
# for why we need to wrap these instead of making them class attributes
# Moreover, cython will choose the appropriate-dtyped sub-function
# given the dtypes of the passed arguments
def _left_indexer_unique(self, left, right):
return libjoin.left_join_indexer_unique(left, right)
def _left_indexer(self, left, right):
return libjoin.left_join_indexer(left, right)
def _inner_indexer(self, left, right):
return libjoin.inner_join_indexer(left, right)
def _outer_indexer(self, left, right):
return libjoin.outer_join_indexer(left, right)
_typ = "index"
_data: Union[ExtensionArray, np.ndarray]
_id = None
name = None
_comparables = ["name"]
_attributes = ["name"]
_is_numeric_dtype = False
_can_hold_na = True
# would we like our indexing holder to defer to us
_defer_to_indexing = False
# prioritize current class for _shallow_copy_with_infer,
# used to infer integers as datetime-likes
_infer_as_myclass = False
_engine_type = libindex.ObjectEngine
# whether we support partial string indexing. Overridden
# in DatetimeIndex and PeriodIndex
_supports_partial_string_indexing = False
_accessors = {"str"}
str = CachedAccessor("str", StringMethods)
# --------------------------------------------------------------------
# Constructors
def __new__(
cls, data=None, dtype=None, copy=False, name=None, tupleize_cols=True, **kwargs,
) -> "Index":
from .range import RangeIndex
from pandas import PeriodIndex, DatetimeIndex, TimedeltaIndex
from .numeric import Float64Index, Int64Index, UInt64Index
from .interval import IntervalIndex
from .category import CategoricalIndex
if name is None and hasattr(data, "name"):
name = data.name
if isinstance(data, ABCPandasArray):
# ensure users don't accidentally put a PandasArray in an index.
data = data.to_numpy()
# range
if isinstance(data, RangeIndex):
return RangeIndex(start=data, copy=copy, dtype=dtype, name=name)
elif isinstance(data, range):
return RangeIndex.from_range(data, dtype=dtype, name=name)
# categorical
elif is_categorical_dtype(data) or is_categorical_dtype(dtype):
return CategoricalIndex(data, dtype=dtype, copy=copy, name=name, **kwargs)
# interval
elif (
is_interval_dtype(data) or is_interval_dtype(dtype)
) and not is_object_dtype(dtype):
closed = kwargs.get("closed", None)
return IntervalIndex(data, dtype=dtype, name=name, copy=copy, closed=closed)
elif (
is_datetime64_any_dtype(data)
or is_datetime64_any_dtype(dtype)
or "tz" in kwargs
):
if is_dtype_equal(_o_dtype, dtype):
# GH#23524 passing `dtype=object` to DatetimeIndex is invalid,
# will raise in the where `data` is already tz-aware. So
# we leave it out of this step and cast to object-dtype after
# the DatetimeIndex construction.
# Note we can pass copy=False because the .astype below
# will always make a copy
return DatetimeIndex(data, copy=False, name=name, **kwargs).astype(
object
)
else:
return DatetimeIndex(data, copy=copy, name=name, dtype=dtype, **kwargs)
elif is_timedelta64_dtype(data) or is_timedelta64_dtype(dtype):
if is_dtype_equal(_o_dtype, dtype):
# Note we can pass copy=False because the .astype below
# will always make a copy
return TimedeltaIndex(data, copy=False, name=name, **kwargs).astype(
object
)
else:
return TimedeltaIndex(data, copy=copy, name=name, dtype=dtype, **kwargs)
elif is_period_dtype(data) and not is_object_dtype(dtype):
return PeriodIndex(data, copy=copy, name=name, **kwargs)
# extension dtype
elif is_extension_array_dtype(data) or is_extension_array_dtype(dtype):
data = np.asarray(data)
if not (dtype is None or is_object_dtype(dtype)):
# coerce to the provided dtype
ea_cls = dtype.construct_array_type()
data = ea_cls._from_sequence(data, dtype=dtype, copy=False)
# coerce to the object dtype
data = data.astype(object)
return Index(data, dtype=object, copy=copy, name=name, **kwargs)
# index-like
elif isinstance(data, (np.ndarray, Index, ABCSeries)):
if dtype is not None:
# we need to avoid having numpy coerce
# things that look like ints/floats to ints unless
# they are actually ints, e.g. '0' and 0.0
# should not be coerced
# GH 11836
if is_integer_dtype(dtype):
inferred = lib.infer_dtype(data, skipna=False)
if inferred == "integer":
data = maybe_cast_to_integer_array(data, dtype, copy=copy)
elif inferred in ["floating", "mixed-integer-float"]:
if isna(data).any():
raise ValueError("cannot convert float NaN to integer")
if inferred == "mixed-integer-float":
data = maybe_cast_to_integer_array(data, dtype)
# If we are actually all equal to integers,
# then coerce to integer.
try:
return cls._try_convert_to_int_index(
data, copy, name, dtype
)
except ValueError:
pass
# Return an actual float index.
return Float64Index(data, copy=copy, name=name)
elif inferred == "string":
pass
else:
data = data.astype(dtype)
elif is_float_dtype(dtype):
inferred = lib.infer_dtype(data, skipna=False)
if inferred == "string":
pass
else:
data = data.astype(dtype)
else:
data = np.array(data, dtype=dtype, copy=copy)
# maybe coerce to a sub-class
if is_signed_integer_dtype(data.dtype):
return Int64Index(data, copy=copy, dtype=dtype, name=name)
elif is_unsigned_integer_dtype(data.dtype):
return UInt64Index(data, copy=copy, dtype=dtype, name=name)
elif is_float_dtype(data.dtype):
return Float64Index(data, copy=copy, dtype=dtype, name=name)
elif issubclass(data.dtype.type, np.bool) or is_bool_dtype(data):
subarr = data.astype("object")
else:
subarr = com.asarray_tuplesafe(data, dtype=object)
# asarray_tuplesafe does not always copy underlying data,
# so need to make sure that this happens
if copy:
subarr = subarr.copy()
if dtype is None:
inferred = lib.infer_dtype(subarr, skipna=False)
if inferred == "integer":
try:
return cls._try_convert_to_int_index(subarr, copy, name, dtype)
except ValueError:
pass
return Index(subarr, copy=copy, dtype=object, name=name)
elif inferred in ["floating", "mixed-integer-float", "integer-na"]:
# TODO: Returns IntegerArray for integer-na case in the future
return Float64Index(subarr, copy=copy, name=name)
elif inferred == "interval":
try:
return IntervalIndex(subarr, name=name, copy=copy)
except ValueError:
# GH27172: mixed closed Intervals --> object dtype
pass
elif inferred == "boolean":
# don't support boolean explicitly ATM
pass
elif inferred != "string":
if inferred.startswith("datetime"):
try:
return DatetimeIndex(subarr, copy=copy, name=name, **kwargs)
except (ValueError, OutOfBoundsDatetime):
# GH 27011
# If we have mixed timezones, just send it
# down the base constructor
pass
elif inferred.startswith("timedelta"):
return TimedeltaIndex(subarr, copy=copy, name=name, **kwargs)
elif inferred == "period":
try:
return PeriodIndex(subarr, name=name, **kwargs)
except IncompatibleFrequency:
pass
if kwargs:
raise TypeError(f"Unexpected keyword arguments {repr(set(kwargs))}")
return cls._simple_new(subarr, name, **kwargs)
elif hasattr(data, "__array__"):
return Index(np.asarray(data), dtype=dtype, copy=copy, name=name, **kwargs)
elif data is None or is_scalar(data):
raise cls._scalar_data_error(data)
else:
if tupleize_cols and is_list_like(data):
# GH21470: convert iterable to list before determining if empty
if is_iterator(data):
data = list(data)
if data and all(isinstance(e, tuple) for e in data):
# we must be all tuples, otherwise don't construct
# 10697
from .multi import MultiIndex
return MultiIndex.from_tuples(
data, names=name or kwargs.get("names")
)
# other iterable of some kind
subarr = com.asarray_tuplesafe(data, dtype=object)
return Index(subarr, dtype=dtype, copy=copy, name=name, **kwargs)
"""
NOTE for new Index creation:
- _simple_new: It returns new Index with the same type as the caller.
All metadata (such as name) must be provided by caller's responsibility.
Using _shallow_copy is recommended because it fills these metadata
otherwise specified.
- _shallow_copy: It returns new Index with the same type (using
_simple_new), but fills caller's metadata otherwise specified. Passed
kwargs will overwrite corresponding metadata.
- _shallow_copy_with_infer: It returns new Index inferring its type
from passed values. It fills caller's metadata otherwise specified as the
same as _shallow_copy.
See each method's docstring.
"""
@property
def asi8(self):
"""
Integer representation of the values.
Returns
-------
ndarray
An ndarray with int64 dtype.
"""
return None
@classmethod
def _simple_new(cls, values, name=None, dtype=None):
"""
We require that we have a dtype compat for the values. If we are passed
a non-dtype compat, then coerce using the constructor.
Must be careful not to recurse.
"""
if isinstance(values, (ABCSeries, ABCIndexClass)):
# Index._data must always be an ndarray.
# This is no-copy for when _values is an ndarray,
# which should be always at this point.
values = np.asarray(values._values)
result = object.__new__(cls)
result._data = values
# _index_data is a (temporary?) fix to ensure that the direct data
# manipulation we do in `_libs/reduction.pyx` continues to work.
# We need access to the actual ndarray, since we're messing with
# data buffers and strides. We don't re-use `_ndarray_values`, since
# we actually set this value too.
result._index_data = values
result.name = name
return result._reset_identity()
@cache_readonly
def _constructor(self):
return type(self)
# --------------------------------------------------------------------
# Index Internals Methods
def _get_attributes_dict(self):
"""
Return an attributes dict for my class.
"""
return {k: getattr(self, k, None) for k in self._attributes}
_index_shared_docs[
"_shallow_copy"
] = """
Create a new Index with the same class as the caller, don't copy the
data, use the same object attributes with passed in attributes taking
precedence.
*this is an internal non-public method*
Parameters
----------
values : the values to create the new Index, optional
kwargs : updates the default attributes for this Index
"""
@Appender(_index_shared_docs["_shallow_copy"])
def _shallow_copy(self, values=None, **kwargs):
if values is None:
values = self.values
attributes = self._get_attributes_dict()
attributes.update(kwargs)
if not len(values) and "dtype" not in kwargs:
attributes["dtype"] = self.dtype
# _simple_new expects an the type of self._data
values = getattr(values, "_values", values)
if isinstance(values, ABCDatetimeArray):
# `self.values` returns `self` for tz-aware, so we need to unwrap
# more specifically
values = values.asi8
return self._simple_new(values, **attributes)
def _shallow_copy_with_infer(self, values, **kwargs):
"""
Create a new Index inferring the class with passed value, don't copy
the data, use the same object attributes with passed in attributes
taking precedence.
*this is an internal non-public method*
Parameters
----------
values : the values to create the new Index, optional
kwargs : updates the default attributes for this Index
"""
attributes = self._get_attributes_dict()
attributes.update(kwargs)
attributes["copy"] = False
if not len(values) and "dtype" not in kwargs:
attributes["dtype"] = self.dtype
if self._infer_as_myclass:
try:
return self._constructor(values, **attributes)
except (TypeError, ValueError):
pass
return Index(values, **attributes)
def _update_inplace(self, result, **kwargs):
# guard when called from IndexOpsMixin
raise TypeError("Index can't be updated inplace")
def is_(self, other) -> bool:
"""
More flexible, faster check like ``is`` but that works through views.
Note: this is *not* the same as ``Index.identical()``, which checks
that metadata is also the same.
Parameters
----------
other : object
other object to compare against.
Returns
-------
True if both have same underlying data, False otherwise : bool
"""
# use something other than None to be clearer
return self._id is getattr(other, "_id", Ellipsis) and self._id is not None
def _reset_identity(self):
"""
Initializes or resets ``_id`` attribute with new object.
"""
self._id = _Identity()
return self
def _cleanup(self):
self._engine.clear_mapping()
@cache_readonly
def _engine(self):
# property, for now, slow to look up
# to avoid a reference cycle, bind `_ndarray_values` to a local variable, so
# `self` is not passed into the lambda.
_ndarray_values = self._ndarray_values
return self._engine_type(lambda: _ndarray_values, len(self))
# --------------------------------------------------------------------
# Array-Like Methods
# ndarray compat
def __len__(self) -> int:
"""
Return the length of the Index.
"""
return len(self._data)
def __array__(self, dtype=None):
"""
The array interface, return my values.
"""
return np.asarray(self._data, dtype=dtype)
def __array_wrap__(self, result, context=None):
"""
Gets called after a ufunc.
"""
result = lib.item_from_zerodim(result)
if is_bool_dtype(result) or lib.is_scalar(result):
return result
attrs = self._get_attributes_dict()
return Index(result, **attrs)
@cache_readonly
def dtype(self):
"""
Return the dtype object of the underlying data.
"""
return self._data.dtype
def ravel(self, order="C"):
"""
Return an ndarray of the flattened values of the underlying data.
Returns
-------
numpy.ndarray
Flattened array.
See Also
--------
numpy.ndarray.ravel
"""
return self._ndarray_values.ravel(order=order)
def view(self, cls=None):
# we need to see if we are subclassing an
# index type here
if cls is not None and not hasattr(cls, "_typ"):
result = self._data.view(cls)
else:
result = self._shallow_copy()
if isinstance(result, Index):
result._id = self._id
return result
_index_shared_docs[
"astype"
] = """
Create an Index with values cast to dtypes. The class of a new Index
is determined by dtype. When conversion is impossible, a ValueError
exception is raised.
Parameters
----------
dtype : numpy dtype or pandas type
Note that any signed integer `dtype` is treated as ``'int64'``,
and any unsigned integer `dtype` is treated as ``'uint64'``,
regardless of the size.
copy : bool, default True
By default, astype always returns a newly allocated object.
If copy is set to False and internal requirements on dtype are
satisfied, the original data is used to create a new Index
or the original Index is returned.
Returns
-------
Index
Index with values cast to specified dtype.
"""
@Appender(_index_shared_docs["astype"])
def astype(self, dtype, copy=True):
if is_dtype_equal(self.dtype, dtype):
return self.copy() if copy else self
elif is_categorical_dtype(dtype):
from .category import CategoricalIndex
return CategoricalIndex(self.values, name=self.name, dtype=dtype, copy=copy)
elif is_extension_array_dtype(dtype):
return Index(np.asarray(self), dtype=dtype, copy=copy)
try:
return Index(
self.values.astype(dtype, copy=copy), name=self.name, dtype=dtype
)
except (TypeError, ValueError):
raise TypeError(f"Cannot cast {type(self).__name__} to dtype {dtype}")
_index_shared_docs[
"take"
] = """
Return a new %(klass)s of the values selected by the indices.
For internal compatibility with numpy arrays.
Parameters
----------
indices : list
Indices to be taken.
axis : int, optional
The axis over which to select values, always 0.
allow_fill : bool, default True
fill_value : bool, default None
If allow_fill=True and fill_value is not None, indices specified by
-1 is regarded as NA. If Index doesn't hold NA, raise ValueError.
Returns
-------
numpy.ndarray
Elements of given indices.
See Also
--------
numpy.ndarray.take
"""
@Appender(_index_shared_docs["take"] % _index_doc_kwargs)
def take(self, indices, axis=0, allow_fill=True, fill_value=None, **kwargs):
if kwargs:
nv.validate_take(tuple(), kwargs)
indices = ensure_platform_int(indices)
if self._can_hold_na:
taken = self._assert_take_fillable(
self.values,
indices,
allow_fill=allow_fill,
fill_value=fill_value,
na_value=self._na_value,
)
else:
if allow_fill and fill_value is not None:
cls_name = type(self).__name__
raise ValueError(
f"Unable to fill values because {cls_name} cannot contain NA"
)
taken = self.values.take(indices)
return self._shallow_copy(taken)
def _assert_take_fillable(
self, values, indices, allow_fill=True, fill_value=None, na_value=np.nan
):
"""
Internal method to handle NA filling of take.
"""
indices = ensure_platform_int(indices)
# only fill if we are passing a non-None fill_value
if allow_fill and fill_value is not None:
if (indices < -1).any():
msg = (
"When allow_fill=True and fill_value is not None, "
"all indices must be >= -1"
)
raise ValueError(msg)
taken = algos.take(
values, indices, allow_fill=allow_fill, fill_value=na_value
)
else:
taken = values.take(indices)
return taken
_index_shared_docs[
"repeat"
] = """
Repeat elements of a %(klass)s.
Returns a new %(klass)s where each element of the current %(klass)s
is repeated consecutively a given number of times.
Parameters
----------
repeats : int or array of ints
The number of repetitions for each element. This should be a
non-negative integer. Repeating 0 times will return an empty
%(klass)s.
axis : None
Must be ``None``. Has no effect but is accepted for compatibility
with numpy.
Returns
-------
repeated_index : %(klass)s
Newly created %(klass)s with repeated elements.
See Also
--------
Series.repeat : Equivalent function for Series.
numpy.repeat : Similar method for :class:`numpy.ndarray`.
Examples
--------
>>> idx = pd.Index(['a', 'b', 'c'])
>>> idx
Index(['a', 'b', 'c'], dtype='object')
>>> idx.repeat(2)
Index(['a', 'a', 'b', 'b', 'c', 'c'], dtype='object')
>>> idx.repeat([1, 2, 3])
Index(['a', 'b', 'b', 'c', 'c', 'c'], dtype='object')
"""
@Appender(_index_shared_docs["repeat"] % _index_doc_kwargs)
def repeat(self, repeats, axis=None):
repeats = ensure_platform_int(repeats)
nv.validate_repeat(tuple(), dict(axis=axis))
return self._shallow_copy(self._values.repeat(repeats))
# --------------------------------------------------------------------
# Copying Methods
_index_shared_docs[
"copy"
] = """
Make a copy of this object. Name and dtype sets those attributes on
the new object.
Parameters
----------
name : str, optional
deep : bool, default False
dtype : numpy dtype or pandas type
Returns
-------
copy : Index
Notes
-----
In most cases, there should be no functional difference from using
``deep``, but if ``deep`` is passed it will attempt to deepcopy.
"""
@Appender(_index_shared_docs["copy"])
def copy(self, name=None, deep=False, dtype=None, **kwargs):
if deep:
new_index = self._shallow_copy(self._data.copy())
else:
new_index = self._shallow_copy()
names = kwargs.get("names")
names = self._validate_names(name=name, names=names, deep=deep)
new_index = new_index.set_names(names)
if dtype:
new_index = new_index.astype(dtype)
return new_index
def __copy__(self, **kwargs):
return self.copy(**kwargs)
def __deepcopy__(self, memo=None):
"""
Parameters
----------
memo, default None
Standard signature. Unused
"""
if memo is None:
memo = {}
return self.copy(deep=True)
# --------------------------------------------------------------------
# Rendering Methods
def __repr__(self):
"""
Return a string representation for this object.
"""
klass_name = type(self).__name__
data = self._format_data()
attrs = self._format_attrs()
space = self._format_space()
attrs_str = [f"{k}={v}" for k, v in attrs]
prepr = f",{space}".join(attrs_str)
# no data provided, just attributes
if data is None:
data = ""
res = f"{klass_name}({data}{prepr})"
return res
def _format_space(self):
# using space here controls if the attributes
# are line separated or not (the default)
# max_seq_items = get_option('display.max_seq_items')
# if len(self) > max_seq_items:
# space = "\n%s" % (' ' * (len(klass) + 1))
return " "
@property
def _formatter_func(self):
"""
Return the formatter function.
"""
return default_pprint
def _format_data(self, name=None):
"""
Return the formatted data as a unicode string.
"""
# do we want to justify (only do so for non-objects)
is_justify = not (
self.inferred_type in ("string", "unicode")
or (
self.inferred_type == "categorical" and is_object_dtype(self.categories)
)
)
return format_object_summary(
self, self._formatter_func, is_justify=is_justify, name=name
)
def _format_attrs(self):
"""
Return a list of tuples of the (attr,formatted_value).
"""
return format_object_attrs(self)
def _mpl_repr(self):
# how to represent ourselves to matplotlib
return self.values
def format(self, name=False, formatter=None, **kwargs):
"""
Render a string representation of the Index.
"""
header = []
if name:
header.append(
pprint_thing(self.name, escape_chars=("\t", "\r", "\n"))
if self.name is not None
else ""
)
if formatter is not None:
return header + list(self.map(formatter))
return self._format_with_header(header, **kwargs)
def _format_with_header(self, header, na_rep="NaN", **kwargs):
values = self.values
from pandas.io.formats.format import format_array
if is_categorical_dtype(values.dtype):
values = np.array(values)
elif is_object_dtype(values.dtype):
values = lib.maybe_convert_objects(values, safe=1)
if is_object_dtype(values.dtype):
result = [pprint_thing(x, escape_chars=("\t", "\r", "\n")) for x in values]
# could have nans
mask = isna(values)
if mask.any():
result = np.array(result)
result[mask] = na_rep
result = result.tolist()
else:
result = _trim_front(format_array(values, None, justify="left"))
return header + result
def to_native_types(self, slicer=None, **kwargs):
"""
Format specified values of `self` and return them.
Parameters
----------
slicer : int, array-like
An indexer into `self` that specifies which values
are used in the formatting process.
kwargs : dict
Options for specifying how the values should be formatted.
These options include the following:
1) na_rep : str
The value that serves as a placeholder for NULL values
2) quoting : bool or None
Whether or not there are quoted values in `self`
3) date_format : str
The format used to represent date-like values.
Returns
-------
numpy.ndarray
Formatted values.
"""
values = self
if slicer is not None:
values = values[slicer]
return values._format_native_types(**kwargs)
def _format_native_types(self, na_rep="", quoting=None, **kwargs):
"""
Actually format specific types of the index.
"""
mask = isna(self)
if not self.is_object() and not quoting:
values = np.asarray(self).astype(str)
else:
values = np.array(self, dtype=object, copy=True)
values[mask] = na_rep
return values
def _summary(self, name=None):
"""
Return a summarized representation.
Parameters
----------
name : str
name to use in the summary representation
Returns
-------
String with a summarized representation of the index
"""
if len(self) > 0:
head = self[0]
if hasattr(head, "format") and not isinstance(head, str):
head = head.format()
tail = self[-1]
if hasattr(tail, "format") and not isinstance(tail, str):
tail = tail.format()
index_summary = f", {head} to {tail}"
else:
index_summary = ""
if name is None:
name = type(self).__name__
return f"{name}: {len(self)} entries{index_summary}"
# --------------------------------------------------------------------
# Conversion Methods
def to_flat_index(self):
"""
Identity method.
.. versionadded:: 0.24.0
This is implemented for compatibility with subclass implementations
when chaining.
Returns
-------
pd.Index
Caller.
See Also
--------
MultiIndex.to_flat_index : Subclass implementation.
"""
return self
def to_series(self, index=None, name=None):
"""
Create a Series with both index and values equal to the index keys.
Useful with map for returning an indexer based on an index.
Parameters
----------
index : Index, optional
Index of resulting Series. If None, defaults to original index.
name : str, optional
Dame of resulting Series. If None, defaults to name of original
index.
Returns
-------
Series
The dtype will be based on the type of the Index values.
"""
from pandas import Series
if index is None:
index = self._shallow_copy()
if name is None:
name = self.name
return Series(self.values.copy(), index=index, name=name)
def to_frame(self, index=True, name=None):
"""
Create a DataFrame with a column containing the Index.
.. versionadded:: 0.24.0
Parameters
----------
index : bool, default True
Set the index of the returned DataFrame as the original Index.
name : object, default None
The passed name should substitute for the index name (if it has
one).
Returns
-------
DataFrame
DataFrame containing the original Index data.
See Also
--------
Index.to_series : Convert an Index to a Series.
Series.to_frame : Convert Series to DataFrame.
Examples
--------
>>> idx = pd.Index(['Ant', 'Bear', 'Cow'], name='animal')
>>> idx.to_frame()
animal
animal
Ant Ant
Bear Bear
Cow Cow
By default, the original Index is reused. To enforce a new Index:
>>> idx.to_frame(index=False)
animal
0 Ant
1 Bear
2 Cow
To override the name of the resulting column, specify `name`:
>>> idx.to_frame(index=False, name='zoo')
zoo
0 Ant
1 Bear
2 Cow
"""
from pandas import DataFrame
if name is None:
name = self.name or 0
result = DataFrame({name: self._values.copy()})
if index:
result.index = self
return result
# --------------------------------------------------------------------
# Name-Centric Methods
def _validate_names(self, name=None, names=None, deep=False):
"""
Handles the quirks of having a singular 'name' parameter for general
Index and plural 'names' parameter for MultiIndex.
"""
from copy import deepcopy
if names is not None and name is not None:
raise TypeError("Can only provide one of `names` and `name`")
elif names is None and name is None:
return deepcopy(self.names) if deep else self.names
elif names is not None:
if not is_list_like(names):
raise TypeError("Must pass list-like as `names`.")
return names
else:
if not is_list_like(name):
return [name]
return name
def _get_names(self):
return FrozenList((self.name,))
def _set_names(self, values, level=None):
"""
Set new names on index. Each name has to be a hashable type.
Parameters
----------
values : str or sequence
name(s) to set
level : int, level name, or sequence of int/level names (default None)
If the index is a MultiIndex (hierarchical), level(s) to set (None
for all levels). Otherwise level must be None
Raises
------
TypeError if each name is not hashable.
"""
if not is_list_like(values):
raise ValueError("Names must be a list-like")
if len(values) != 1:
raise ValueError(f"Length of new names must be 1, got {len(values)}")
# GH 20527
# All items in 'name' need to be hashable:
for name in values:
if not is_hashable(name):
raise TypeError(f"{type(self).__name__}.name must be a hashable type")
self.name = values[0]
names = property(fset=_set_names, fget=_get_names)
def set_names(self, names, level=None, inplace=False):
"""
Set Index or MultiIndex name.
Able to set new names partially and by level.
Parameters
----------
names : label or list of label
Name(s) to set.
level : int, label or list of int or label, optional
If the index is a MultiIndex, level(s) to set (None for all
levels). Otherwise level must be None.
inplace : bool, default False
Modifies the object directly, instead of creating a new Index or
MultiIndex.
Returns
-------
Index
The same type as the caller or None if inplace is True.
See Also
--------
Index.rename : Able to set new names without level.
Examples
--------
>>> idx = pd.Index([1, 2, 3, 4])
>>> idx
Int64Index([1, 2, 3, 4], dtype='int64')
>>> idx.set_names('quarter')
Int64Index([1, 2, 3, 4], dtype='int64', name='quarter')
>>> idx = pd.MultiIndex.from_product([['python', 'cobra'],
... [2018, 2019]])
>>> idx
MultiIndex([('python', 2018),
('python', 2019),
( 'cobra', 2018),
( 'cobra', 2019)],
)
>>> idx.set_names(['kind', 'year'], inplace=True)
>>> idx
MultiIndex([('python', 2018),
('python', 2019),
( 'cobra', 2018),
( 'cobra', 2019)],
names=['kind', 'year'])
>>> idx.set_names('species', level=0)
MultiIndex([('python', 2018),
('python', 2019),
( 'cobra', 2018),
( 'cobra', 2019)],
names=['species', 'year'])
"""
if level is not None and not isinstance(self, ABCMultiIndex):
raise ValueError("Level must be None for non-MultiIndex")
if level is not None and not is_list_like(level) and is_list_like(names):
msg = "Names must be a string when a single level is provided."
raise TypeError(msg)
if not is_list_like(names) and level is None and self.nlevels > 1:
raise TypeError("Must pass list-like as `names`.")
if not is_list_like(names):
names = [names]
if level is not None and not is_list_like(level):
level = [level]
if inplace:
idx = self
else:
idx = self._shallow_copy()
idx._set_names(names, level=level)
if not inplace:
return idx
def rename(self, name, inplace=False):
"""
Alter Index or MultiIndex name.
Able to set new names without level. Defaults to returning new index.
Length of names must match number of levels in MultiIndex.
Parameters
----------
name : label or list of labels
Name(s) to set.
inplace : bool, default False
Modifies the object directly, instead of creating a new Index or
MultiIndex.
Returns
-------
Index
The same type as the caller or None if inplace is True.
See Also
--------
Index.set_names : Able to set new names partially and by level.
Examples
--------
>>> idx = pd.Index(['A', 'C', 'A', 'B'], name='score')
>>> idx.rename('grade')
Index(['A', 'C', 'A', 'B'], dtype='object', name='grade')
>>> idx = pd.MultiIndex.from_product([['python', 'cobra'],
... [2018, 2019]],
... names=['kind', 'year'])
>>> idx
MultiIndex([('python', 2018),
('python', 2019),
( 'cobra', 2018),
( 'cobra', 2019)],
names=['kind', 'year'])
>>> idx.rename(['species', 'year'])
MultiIndex([('python', 2018),
('python', 2019),
( 'cobra', 2018),
( 'cobra', 2019)],
names=['species', 'year'])
>>> idx.rename('species')
Traceback (most recent call last):
TypeError: Must pass list-like as `names`.
"""
return self.set_names([name], inplace=inplace)
# --------------------------------------------------------------------
# Level-Centric Methods
@property
def nlevels(self) -> int:
"""
Number of levels.
"""
return 1
def _sort_levels_monotonic(self):
"""
Compat with MultiIndex.
"""
return self
def _validate_index_level(self, level):
"""
Validate index level.
For single-level Index getting level number is a no-op, but some
verification must be done like in MultiIndex.
"""
if isinstance(level, int):
if level < 0 and level != -1:
raise IndexError(
f"Too many levels: Index has only 1 level,"
f" {level} is not a valid level number"
)
elif level > 0:
raise IndexError(
f"Too many levels: Index has only 1 level, not {level + 1}"
)
elif level != self.name:
raise KeyError(
f"Requested level ({level}) does not match index name ({self.name})"
)
def _get_level_number(self, level):
self._validate_index_level(level)
return 0
def sortlevel(self, level=None, ascending=True, sort_remaining=None):
"""
For internal compatibility with with the Index API.
Sort the Index. This is for compat with MultiIndex
Parameters
----------
ascending : bool, default True
False to sort in descending order
level, sort_remaining are compat parameters
Returns
-------
Index
"""
return self.sort_values(return_indexer=True, ascending=ascending)
def _get_level_values(self, level):
"""
Return an Index of values for requested level.
This is primarily useful to get an individual level of values from a
MultiIndex, but is provided on Index as well for compatibility.
Parameters
----------
level : int or str
It is either the integer position or the name of the level.
Returns
-------
Index
Calling object, as there is only one level in the Index.
See Also
--------
MultiIndex.get_level_values : Get values for a level of a MultiIndex.
Notes
-----
For Index, level should be 0, since there are no multiple levels.
Examples
--------
>>> idx = pd.Index(list('abc'))
>>> idx
Index(['a', 'b', 'c'], dtype='object')
Get level values by supplying `level` as integer:
>>> idx.get_level_values(0)
Index(['a', 'b', 'c'], dtype='object')
"""
self._validate_index_level(level)
return self
get_level_values = _get_level_values
def droplevel(self, level=0):
"""
Return index with requested level(s) removed.
If resulting index has only 1 level left, the result will be
of Index type, not MultiIndex.
.. versionadded:: 0.23.1 (support for non-MultiIndex)
Parameters
----------
level : int, str, or list-like, default 0
If a string is given, must be the name of a level
If list-like, elements must be names or indexes of levels.
Returns
-------
Index or MultiIndex
"""
if not isinstance(level, (tuple, list)):
level = [level]
levnums = sorted(self._get_level_number(lev) for lev in level)[::-1]
if len(level) == 0:
return self
if len(level) >= self.nlevels:
raise ValueError(
f"Cannot remove {len(level)} levels from an index with {self.nlevels} "
"levels: at least one level must be left."
)
# The two checks above guarantee that here self is a MultiIndex
new_levels = list(self.levels)
new_codes = list(self.codes)
new_names = list(self.names)
for i in levnums:
new_levels.pop(i)
new_codes.pop(i)
new_names.pop(i)
if len(new_levels) == 1:
# set nan if needed
mask = new_codes[0] == -1
result = new_levels[0].take(new_codes[0])
if mask.any():
result = result.putmask(mask, np.nan)
result.name = new_names[0]
return result
else:
from .multi import MultiIndex
return MultiIndex(
levels=new_levels,
codes=new_codes,
names=new_names,
verify_integrity=False,
)
_index_shared_docs[
"_get_grouper_for_level"
] = """
Get index grouper corresponding to an index level
Parameters
----------
mapper: Group mapping function or None
Function mapping index values to groups
level : int or None
Index level
Returns
-------
grouper : Index
Index of values to group on.
labels : ndarray of int or None
Array of locations in level_index.
uniques : Index or None
Index of unique values for level.
"""
@Appender(_index_shared_docs["_get_grouper_for_level"])
def _get_grouper_for_level(self, mapper, level=None):
assert level is None or level == 0
if mapper is None:
grouper = self
else:
grouper = self.map(mapper)
return grouper, None, None
# --------------------------------------------------------------------
# Introspection Methods
@property
def is_monotonic(self) -> bool:
"""
Alias for is_monotonic_increasing.
"""
return self.is_monotonic_increasing
@property
def is_monotonic_increasing(self):
"""
Return if the index is monotonic increasing (only equal or
increasing) values.
Examples
--------
>>> Index([1, 2, 3]).is_monotonic_increasing
True
>>> Index([1, 2, 2]).is_monotonic_increasing
True
>>> Index([1, 3, 2]).is_monotonic_increasing
False
"""
return self._engine.is_monotonic_increasing
@property
def is_monotonic_decreasing(self) -> bool:
"""
Return if the index is monotonic decreasing (only equal or
decreasing) values.
Examples
--------
>>> Index([3, 2, 1]).is_monotonic_decreasing
True
>>> Index([3, 2, 2]).is_monotonic_decreasing
True
>>> Index([3, 1, 2]).is_monotonic_decreasing
False
"""
return self._engine.is_monotonic_decreasing
@property
def _is_strictly_monotonic_increasing(self) -> bool:
"""
Return if the index is strictly monotonic increasing
(only increasing) values.
Examples
--------
>>> Index([1, 2, 3])._is_strictly_monotonic_increasing
True
>>> Index([1, 2, 2])._is_strictly_monotonic_increasing
False
>>> Index([1, 3, 2])._is_strictly_monotonic_increasing
False
"""
return self.is_unique and self.is_monotonic_increasing
@property
def _is_strictly_monotonic_decreasing(self) -> bool:
"""
Return if the index is strictly monotonic decreasing
(only decreasing) values.
Examples
--------
>>> Index([3, 2, 1])._is_strictly_monotonic_decreasing
True
>>> Index([3, 2, 2])._is_strictly_monotonic_decreasing
False
>>> Index([3, 1, 2])._is_strictly_monotonic_decreasing
False
"""
return self.is_unique and self.is_monotonic_decreasing
@cache_readonly
def is_unique(self) -> bool:
"""
Return if the index has unique values.
"""
return self._engine.is_unique
@property
def has_duplicates(self) -> bool:
return not self.is_unique
def is_boolean(self) -> bool:
return self.inferred_type in ["boolean"]
def is_integer(self) -> bool:
return self.inferred_type in ["integer"]
def is_floating(self) -> bool:
return self.inferred_type in ["floating", "mixed-integer-float", "integer-na"]
def is_numeric(self) -> bool:
return self.inferred_type in ["integer", "floating"]
def is_object(self) -> bool:
return is_object_dtype(self.dtype)
def is_categorical(self) -> bool:
"""
Check if the Index holds categorical data.
Returns
-------
boolean
True if the Index is categorical.
See Also
--------
CategoricalIndex : Index for categorical data.
Examples
--------
>>> idx = pd.Index(["Watermelon", "Orange", "Apple",
... "Watermelon"]).astype("category")
>>> idx.is_categorical()
True
>>> idx = pd.Index([1, 3, 5, 7])
>>> idx.is_categorical()
False
>>> s = pd.Series(["Peter", "Victor", "Elisabeth", "Mar"])
>>> s
0 Peter
1 Victor
2 Elisabeth
3 Mar
dtype: object
>>> s.index.is_categorical()
False
"""
return self.inferred_type in ["categorical"]
def is_interval(self) -> bool:
return self.inferred_type in ["interval"]
def is_mixed(self) -> bool:
return self.inferred_type in ["mixed"]
def holds_integer(self):
"""
Whether the type is an integer type.
"""
return self.inferred_type in ["integer", "mixed-integer"]
@cache_readonly
def inferred_type(self):
"""
Return a string of the type inferred from the values.
"""
return lib.infer_dtype(self, skipna=False)
@cache_readonly
def is_all_dates(self) -> bool:
return is_datetime_array(ensure_object(self.values))
# --------------------------------------------------------------------
# Pickle Methods
def __reduce__(self):
d = dict(data=self._data)
d.update(self._get_attributes_dict())
return _new_Index, (type(self), d), None
def __setstate__(self, state):
"""
Necessary for making this object picklable.
"""
if isinstance(state, dict):
self._data = state.pop("data")
for k, v in state.items():
setattr(self, k, v)
elif isinstance(state, tuple):
if len(state) == 2:
nd_state, own_state = state
data = np.empty(nd_state[1], dtype=nd_state[2])
np.ndarray.__setstate__(data, nd_state)
self.name = own_state[0]
else: # pragma: no cover
data = np.empty(state)
np.ndarray.__setstate__(data, state)
self._data = data
self._reset_identity()
else:
raise Exception("invalid pickle state")
_unpickle_compat = __setstate__
# --------------------------------------------------------------------
# Null Handling Methods
_na_value = np.nan
"""The expected NA value to use with this index."""
@cache_readonly
def _isnan(self):
"""
Return if each value is NaN.
"""
if self._can_hold_na:
return isna(self)
else:
# shouldn't reach to this condition by checking hasnans beforehand
values = np.empty(len(self), dtype=np.bool_)
values.fill(False)
return values
@cache_readonly
def _nan_idxs(self):
if self._can_hold_na:
return self._isnan.nonzero()[0]
else:
return np.array([], dtype=np.int64)
@cache_readonly
def hasnans(self):
"""
Return if I have any nans; enables various perf speedups.
"""
if self._can_hold_na:
return bool(self._isnan.any())
else:
return False
def isna(self):
"""
Detect missing values.
Return a boolean same-sized object indicating if the values are NA.
NA values, such as ``None``, :attr:`numpy.NaN` or :attr:`pd.NaT`, get
mapped to ``True`` values.
Everything else get mapped to ``False`` values. Characters such as
empty strings `''` or :attr:`numpy.inf` are not considered NA values
(unless you set ``pandas.options.mode.use_inf_as_na = True``).
Returns
-------
numpy.ndarray
A boolean array of whether my values are NA.
See Also
--------
Index.notna : Boolean inverse of isna.
Index.dropna : Omit entries with missing values.
isna : Top-level isna.
Series.isna : Detect missing values in Series object.
Examples
--------
Show which entries in a pandas.Index are NA. The result is an
array.
>>> idx = pd.Index([5.2, 6.0, np.NaN])
>>> idx
Float64Index([5.2, 6.0, nan], dtype='float64')
>>> idx.isna()
array([False, False, True], dtype=bool)
Empty strings are not considered NA values. None is considered an NA
value.
>>> idx = pd.Index(['black', '', 'red', None])
>>> idx
Index(['black', '', 'red', None], dtype='object')
>>> idx.isna()
array([False, False, False, True], dtype=bool)
For datetimes, `NaT` (Not a Time) is considered as an NA value.
>>> idx = pd.DatetimeIndex([pd.Timestamp('1940-04-25'),
... pd.Timestamp(''), None, pd.NaT])
>>> idx
DatetimeIndex(['1940-04-25', 'NaT', 'NaT', 'NaT'],
dtype='datetime64[ns]', freq=None)
>>> idx.isna()
array([False, True, True, True], dtype=bool)
"""
return self._isnan
isnull = isna
def notna(self):
"""
Detect existing (non-missing) values.
Return a boolean same-sized object indicating if the values are not NA.
Non-missing values get mapped to ``True``. Characters such as empty
strings ``''`` or :attr:`numpy.inf` are not considered NA values
(unless you set ``pandas.options.mode.use_inf_as_na = True``).
NA values, such as None or :attr:`numpy.NaN`, get mapped to ``False``
values.
Returns
-------
numpy.ndarray
Boolean array to indicate which entries are not NA.
See Also
--------
Index.notnull : Alias of notna.
Index.isna: Inverse of notna.
notna : Top-level notna.
Examples
--------
Show which entries in an Index are not NA. The result is an
array.
>>> idx = pd.Index([5.2, 6.0, np.NaN])
>>> idx
Float64Index([5.2, 6.0, nan], dtype='float64')
>>> idx.notna()
array([ True, True, False])
Empty strings are not considered NA values. None is considered a NA
value.
>>> idx = pd.Index(['black', '', 'red', None])
>>> idx
Index(['black', '', 'red', None], dtype='object')
>>> idx.notna()
array([ True, True, True, False])
"""
return ~self.isna()
notnull = notna
_index_shared_docs[
"fillna"
] = """
Fill NA/NaN values with the specified value.
Parameters
----------
value : scalar
Scalar value to use to fill holes (e.g. 0).
This value cannot be a list-likes.
downcast : dict, default is None
a dict of item->dtype of what to downcast if possible,
or the string 'infer' which will try to downcast to an appropriate
equal type (e.g. float64 to int64 if possible).
Returns
-------
filled : Index
"""
@Appender(_index_shared_docs["fillna"])
def fillna(self, value=None, downcast=None):
self._assert_can_do_op(value)
if self.hasnans:
result = self.putmask(self._isnan, value)
if downcast is None:
# no need to care metadata other than name
# because it can't have freq if
return Index(result, name=self.name)
return self._shallow_copy()
_index_shared_docs[
"dropna"
] = """
Return Index without NA/NaN values.
Parameters
----------
how : {'any', 'all'}, default 'any'
If the Index is a MultiIndex, drop the value when any or all levels
are NaN.
Returns
-------
valid : Index
"""
@Appender(_index_shared_docs["dropna"])
def dropna(self, how="any"):
if how not in ("any", "all"):
raise ValueError(f"invalid how option: {how}")
if self.hasnans:
return self._shallow_copy(self.values[~self._isnan])
return self._shallow_copy()
# --------------------------------------------------------------------
# Uniqueness Methods
_index_shared_docs[
"index_unique"
] = """
Return unique values in the index. Uniques are returned in order
of appearance, this does NOT sort.
Parameters
----------
level : int or str, optional, default None
Only return values from specified level (for MultiIndex).
.. versionadded:: 0.23.0
Returns
-------
Index without duplicates
See Also
--------
unique
Series.unique
"""
@Appender(_index_shared_docs["index_unique"] % _index_doc_kwargs)
def unique(self, level=None):
if level is not None:
self._validate_index_level(level)
result = super().unique()
return self._shallow_copy(result)
def drop_duplicates(self, keep="first"):
"""
Return Index with duplicate values removed.
Parameters
----------
keep : {'first', 'last', ``False``}, default 'first'
- 'first' : Drop duplicates except for the first occurrence.
- 'last' : Drop duplicates except for the last occurrence.
- ``False`` : Drop all duplicates.
Returns
-------
deduplicated : Index
See Also
--------
Series.drop_duplicates : Equivalent method on Series.
DataFrame.drop_duplicates : Equivalent method on DataFrame.
Index.duplicated : Related method on Index, indicating duplicate
Index values.
Examples
--------
Generate an pandas.Index with duplicate values.
>>> idx = pd.Index(['lama', 'cow', 'lama', 'beetle', 'lama', 'hippo'])
The `keep` parameter controls which duplicate values are removed.
The value 'first' keeps the first occurrence for each
set of duplicated entries. The default value of keep is 'first'.
>>> idx.drop_duplicates(keep='first')
Index(['lama', 'cow', 'beetle', 'hippo'], dtype='object')
The value 'last' keeps the last occurrence for each set of duplicated
entries.
>>> idx.drop_duplicates(keep='last')
Index(['cow', 'beetle', 'lama', 'hippo'], dtype='object')
The value ``False`` discards all sets of duplicated entries.
>>> idx.drop_duplicates(keep=False)
Index(['cow', 'beetle', 'hippo'], dtype='object')
"""
return super().drop_duplicates(keep=keep)
def duplicated(self, keep="first"):
"""
Indicate duplicate index values.
Duplicated values are indicated as ``True`` values in the resulting
array. Either all duplicates, all except the first, or all except the
last occurrence of duplicates can be indicated.
Parameters
----------
keep : {'first', 'last', False}, default 'first'
The value or values in a set of duplicates to mark as missing.
- 'first' : Mark duplicates as ``True`` except for the first
occurrence.
- 'last' : Mark duplicates as ``True`` except for the last
occurrence.
- ``False`` : Mark all duplicates as ``True``.
Returns
-------
numpy.ndarray
See Also
--------
Series.duplicated : Equivalent method on pandas.Series.
DataFrame.duplicated : Equivalent method on pandas.DataFrame.
Index.drop_duplicates : Remove duplicate values from Index.
Examples
--------
By default, for each set of duplicated values, the first occurrence is
set to False and all others to True:
>>> idx = pd.Index(['lama', 'cow', 'lama', 'beetle', 'lama'])
>>> idx.duplicated()
array([False, False, True, False, True])
which is equivalent to
>>> idx.duplicated(keep='first')
array([False, False, True, False, True])
By using 'last', the last occurrence of each set of duplicated values
is set on False and all others on True:
>>> idx.duplicated(keep='last')
array([ True, False, True, False, False])
By setting keep on ``False``, all duplicates are True:
>>> idx.duplicated(keep=False)
array([ True, False, True, False, True])
"""
return super().duplicated(keep=keep)
def _get_unique_index(self, dropna=False):
"""
Returns an index containing unique values.
Parameters
----------
dropna : bool
If True, NaN values are dropped.
Returns
-------
uniques : index
"""
if self.is_unique and not dropna:
return self
values = self.values
if not self.is_unique:
values = self.unique()
if dropna:
try:
if self.hasnans:
values = values[~isna(values)]
except NotImplementedError:
pass
return self._shallow_copy(values)
# --------------------------------------------------------------------
# Arithmetic & Logical Methods
def __add__(self, other):
if isinstance(other, (ABCSeries, ABCDataFrame)):
return NotImplemented
from pandas import Series
return Index(Series(self) + other)
def __radd__(self, other):
from pandas import Series
return Index(other + Series(self))
def __iadd__(self, other):
# alias for __add__
return self + other
def __sub__(self, other):
return Index(np.array(self) - other)
def __rsub__(self, other):
# wrap Series to ensure we pin name correctly
from pandas import Series
return Index(other - Series(self))
def __and__(self, other):
return self.intersection(other)
def __or__(self, other):
return self.union(other)
def __xor__(self, other):
return self.symmetric_difference(other)
def __nonzero__(self):
raise ValueError(
f"The truth value of a {type(self).__name__} is ambiguous. "
"Use a.empty, a.bool(), a.item(), a.any() or a.all()."
)
__bool__ = __nonzero__
# --------------------------------------------------------------------
# Set Operation Methods
def _get_reconciled_name_object(self, other):
"""
If the result of a set operation will be self,
return self, unless the name changes, in which
case make a shallow copy of self.
"""
name = get_op_result_name(self, other)
if self.name != name:
return self._shallow_copy(name=name)
return self
def _union_incompatible_dtypes(self, other, sort):
"""
Casts this and other index to object dtype to allow the formation
of a union between incompatible types.
Parameters
----------
other : Index or array-like
sort : False or None, default False
Whether to sort the resulting index.
* False : do not sort the result.
* None : sort the result, except when `self` and `other` are equal
or when the values cannot be compared.
Returns
-------
Index
"""
this = self.astype(object, copy=False)
# cast to Index for when `other` is list-like
other = Index(other).astype(object, copy=False)
return Index.union(this, other, sort=sort).astype(object, copy=False)
def _is_compatible_with_other(self, other):
"""
Check whether this and the other dtype are compatible with each other.
Meaning a union can be formed between them without needing to be cast
to dtype object.
Parameters
----------
other : Index or array-like
Returns
-------
bool
"""
return type(self) is type(other) and is_dtype_equal(self.dtype, other.dtype)
def _validate_sort_keyword(self, sort):
if sort not in [None, False]:
raise ValueError(
"The 'sort' keyword only takes the values of "
f"None or False; {sort} was passed."
)
def union(self, other, sort=None):
"""
Form the union of two Index objects.
If the Index objects are incompatible, both Index objects will be
cast to dtype('object') first.
.. versionchanged:: 0.25.0
Parameters
----------
other : Index or array-like
sort : bool or None, default None
Whether to sort the resulting Index.
* None : Sort the result, except when
1. `self` and `other` are equal.
2. `self` or `other` has length 0.
3. Some values in `self` or `other` cannot be compared.
A RuntimeWarning is issued in this case.
* False : do not sort the result.
.. versionadded:: 0.24.0
.. versionchanged:: 0.24.1
Changed the default value from ``True`` to ``None``
(without change in behaviour).
Returns
-------
union : Index
Examples
--------
Union matching dtypes
>>> idx1 = pd.Index([1, 2, 3, 4])
>>> idx2 = pd.Index([3, 4, 5, 6])
>>> idx1.union(idx2)
Int64Index([1, 2, 3, 4, 5, 6], dtype='int64')
Union mismatched dtypes
>>> idx1 = pd.Index(['a', 'b', 'c', 'd'])
>>> idx2 = pd.Index([1, 2, 3, 4])
>>> idx1.union(idx2)
Index(['a', 'b', 'c', 'd', 1, 2, 3, 4], dtype='object')
"""
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
if not self._is_compatible_with_other(other):
return self._union_incompatible_dtypes(other, sort=sort)
return self._union(other, sort=sort)
def _union(self, other, sort):
"""
Specific union logic should go here. In subclasses, union behavior
should be overwritten here rather than in `self.union`.
Parameters
----------
other : Index or array-like
sort : False or None, default False
Whether to sort the resulting index.
* False : do not sort the result.
* None : sort the result, except when `self` and `other` are equal
or when the values cannot be compared.
Returns
-------
Index
"""
if not len(other) or self.equals(other):
return self._get_reconciled_name_object(other)
if not len(self):
return other._get_reconciled_name_object(self)
# TODO(EA): setops-refactor, clean all this up
if is_period_dtype(self) or is_datetime64tz_dtype(self):
lvals = self._ndarray_values
else:
lvals = self._values
if is_period_dtype(other) or is_datetime64tz_dtype(other):
rvals = other._ndarray_values
else:
rvals = other._values
if sort is None and self.is_monotonic and other.is_monotonic:
try:
result = self._outer_indexer(lvals, rvals)[0]
except TypeError:
# incomparable objects
result = list(lvals)
# worth making this faster? a very unusual case
value_set = set(lvals)
result.extend([x for x in rvals if x not in value_set])
else:
# find indexes of things in "other" that are not in "self"
if self.is_unique:
indexer = self.get_indexer(other)
indexer = (indexer == -1).nonzero()[0]
else:
indexer = algos.unique1d(self.get_indexer_non_unique(other)[1])
if len(indexer) > 0:
other_diff = algos.take_nd(rvals, indexer, allow_fill=False)
result = concat_compat((lvals, other_diff))
else:
result = lvals
if sort is None:
try:
result = algos.safe_sort(result)
except TypeError as err:
warnings.warn(
f"{err}, sort order is undefined for incomparable objects",
RuntimeWarning,
stacklevel=3,
)
# for subclasses
return self._wrap_setop_result(other, result)
def _wrap_setop_result(self, other, result):
return self._constructor(result, name=get_op_result_name(self, other))
_index_shared_docs[
"intersection"
] = """
Form the intersection of two Index objects.
This returns a new Index with elements common to the index and `other`.
Parameters
----------
other : Index or array-like
sort : False or None, default False
Whether to sort the resulting index.
* False : do not sort the result.
* None : sort the result, except when `self` and `other` are equal
or when the values cannot be compared.
.. versionadded:: 0.24.0
.. versionchanged:: 0.24.1
Changed the default from ``True`` to ``False``, to match
the behaviour of 0.23.4 and earlier.
Returns
-------
intersection : Index
Examples
--------
>>> idx1 = pd.Index([1, 2, 3, 4])
>>> idx2 = pd.Index([3, 4, 5, 6])
>>> idx1.intersection(idx2)
Int64Index([3, 4], dtype='int64')
"""
# TODO: standardize return type of non-union setops type(self vs other)
@Appender(_index_shared_docs["intersection"])
def intersection(self, other, sort=False):
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
other = ensure_index(other)
if self.equals(other):
return self._get_reconciled_name_object(other)
if not is_dtype_equal(self.dtype, other.dtype):
this = self.astype("O")
other = other.astype("O")
return this.intersection(other, sort=sort)
# TODO(EA): setops-refactor, clean all this up
if is_period_dtype(self):
lvals = self._ndarray_values
else:
lvals = self._values
if is_period_dtype(other):
rvals = other._ndarray_values
else:
rvals = other._values
if self.is_monotonic and other.is_monotonic:
try:
result = self._inner_indexer(lvals, rvals)[0]
return self._wrap_setop_result(other, result)
except TypeError:
pass
try:
indexer = Index(rvals).get_indexer(lvals)
indexer = indexer.take((indexer != -1).nonzero()[0])
except (InvalidIndexError, IncompatibleFrequency):
# InvalidIndexError raised by get_indexer if non-unique
# IncompatibleFrequency raised by PeriodIndex.get_indexer
indexer = algos.unique1d(Index(rvals).get_indexer_non_unique(lvals)[0])
indexer = indexer[indexer != -1]
taken = other.take(indexer)
if sort is None:
taken = algos.safe_sort(taken.values)
if self.name != other.name:
name = None
else:
name = self.name
return self._shallow_copy(taken, name=name)
if self.name != other.name:
taken.name = None
return taken
def difference(self, other, sort=None):
"""
Return a new Index with elements from the index that are not in
`other`.
This is the set difference of two Index objects.
Parameters
----------
other : Index or array-like
sort : False or None, default None
Whether to sort the resulting index. By default, the
values are attempted to be sorted, but any TypeError from
incomparable elements is caught by pandas.
* None : Attempt to sort the result, but catch any TypeErrors
from comparing incomparable elements.
* False : Do not sort the result.
.. versionadded:: 0.24.0
.. versionchanged:: 0.24.1
Changed the default value from ``True`` to ``None``
(without change in behaviour).
Returns
-------
difference : Index
Examples
--------
>>> idx1 = pd.Index([2, 1, 3, 4])
>>> idx2 = pd.Index([3, 4, 5, 6])
>>> idx1.difference(idx2)
Int64Index([1, 2], dtype='int64')
>>> idx1.difference(idx2, sort=False)
Int64Index([2, 1], dtype='int64')
"""
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
if self.equals(other):
# pass an empty np.ndarray with the appropriate dtype
return self._shallow_copy(self._data[:0])
other, result_name = self._convert_can_do_setop(other)
this = self._get_unique_index()
indexer = this.get_indexer(other)
indexer = indexer.take((indexer != -1).nonzero()[0])
label_diff = np.setdiff1d(np.arange(this.size), indexer, assume_unique=True)
the_diff = this.values.take(label_diff)
if sort is None:
try:
the_diff = algos.safe_sort(the_diff)
except TypeError:
pass
return this._shallow_copy(the_diff, name=result_name)
def symmetric_difference(self, other, result_name=None, sort=None):
"""
Compute the symmetric difference of two Index objects.
Parameters
----------
other : Index or array-like
result_name : str
sort : False or None, default None
Whether to sort the resulting index. By default, the
values are attempted to be sorted, but any TypeError from
incomparable elements is caught by pandas.
* None : Attempt to sort the result, but catch any TypeErrors
from comparing incomparable elements.
* False : Do not sort the result.
.. versionadded:: 0.24.0
.. versionchanged:: 0.24.1
Changed the default value from ``True`` to ``None``
(without change in behaviour).
Returns
-------
symmetric_difference : Index
Notes
-----
``symmetric_difference`` contains elements that appear in either
``idx1`` or ``idx2`` but not both. Equivalent to the Index created by
``idx1.difference(idx2) | idx2.difference(idx1)`` with duplicates
dropped.
Examples
--------
>>> idx1 = pd.Index([1, 2, 3, 4])
>>> idx2 = pd.Index([2, 3, 4, 5])
>>> idx1.symmetric_difference(idx2)
Int64Index([1, 5], dtype='int64')
You can also use the ``^`` operator:
>>> idx1 ^ idx2
Int64Index([1, 5], dtype='int64')
"""
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
other, result_name_update = self._convert_can_do_setop(other)
if result_name is None:
result_name = result_name_update
this = self._get_unique_index()
other = other._get_unique_index()
indexer = this.get_indexer(other)
# {this} minus {other}
common_indexer = indexer.take((indexer != -1).nonzero()[0])
left_indexer = np.setdiff1d(
np.arange(this.size), common_indexer, assume_unique=True
)
left_diff = this.values.take(left_indexer)
# {other} minus {this}
right_indexer = (indexer == -1).nonzero()[0]
right_diff = other.values.take(right_indexer)
the_diff = concat_compat([left_diff, right_diff])
if sort is None:
try:
the_diff = algos.safe_sort(the_diff)
except TypeError:
pass
attribs = self._get_attributes_dict()
attribs["name"] = result_name
if "freq" in attribs:
attribs["freq"] = None
return self._shallow_copy_with_infer(the_diff, **attribs)
def _assert_can_do_setop(self, other):
if not is_list_like(other):
raise TypeError("Input must be Index or array-like")
return True
def _convert_can_do_setop(self, other):
if not isinstance(other, Index):
other = Index(other, name=self.name)
result_name = self.name
else:
result_name = get_op_result_name(self, other)
return other, result_name
# --------------------------------------------------------------------
# Indexing Methods
_index_shared_docs[
"get_loc"
] = """
Get integer location, slice or boolean mask for requested label.
Parameters
----------
key : label
method : {None, 'pad'/'ffill', 'backfill'/'bfill', 'nearest'}, optional
* default: exact matches only.
* pad / ffill: find the PREVIOUS index value if no exact match.
* backfill / bfill: use NEXT index value if no exact match
* nearest: use the NEAREST index value if no exact match. Tied
distances are broken by preferring the larger index value.
tolerance : int or float, optional
Maximum distance from index value for inexact matches. The value of
the index at the matching location most satisfy the equation
``abs(index[loc] - key) <= tolerance``.
.. versionadded:: 0.21.0 (list-like tolerance)
Returns
-------
loc : int if unique index, slice if monotonic index, else mask
Examples
--------
>>> unique_index = pd.Index(list('abc'))
>>> unique_index.get_loc('b')
1
>>> monotonic_index = pd.Index(list('abbc'))
>>> monotonic_index.get_loc('b')
slice(1, 3, None)
>>> non_monotonic_index = pd.Index(list('abcb'))
>>> non_monotonic_index.get_loc('b')
array([False, True, False, True], dtype=bool)
"""
@Appender(_index_shared_docs["get_loc"])
def get_loc(self, key, method=None, tolerance=None):
if method is None:
if tolerance is not None:
raise ValueError(
"tolerance argument only valid if using pad, "
"backfill or nearest lookups"
)
try:
return self._engine.get_loc(key)
except KeyError:
return self._engine.get_loc(self._maybe_cast_indexer(key))
indexer = self.get_indexer([key], method=method, tolerance=tolerance)
if indexer.ndim > 1 or indexer.size > 1:
raise TypeError("get_loc requires scalar valued input")
loc = indexer.item()
if loc == -1:
raise KeyError(key)
return loc
_index_shared_docs[
"get_indexer"
] = """
Compute indexer and mask for new index given the current index. The
indexer should be then used as an input to ndarray.take to align the
current data to the new index.
Parameters
----------
target : %(target_klass)s
method : {None, 'pad'/'ffill', 'backfill'/'bfill', 'nearest'}, optional
* default: exact matches only.
* pad / ffill: find the PREVIOUS index value if no exact match.
* backfill / bfill: use NEXT index value if no exact match
* nearest: use the NEAREST index value if no exact match. Tied
distances are broken by preferring the larger index value.
limit : int, optional
Maximum number of consecutive labels in ``target`` to match for
inexact matches.
tolerance : optional
Maximum distance between original and new labels for inexact
matches. The values of the index at the matching locations most
satisfy the equation ``abs(index[indexer] - target) <= tolerance``.
Tolerance may be a scalar value, which applies the same tolerance
to all values, or list-like, which applies variable tolerance per
element. List-like includes list, tuple, array, Series, and must be
the same size as the index and its dtype must exactly match the
index's type.
.. versionadded:: 0.21.0 (list-like tolerance)
Returns
-------
indexer : ndarray of int
Integers from 0 to n - 1 indicating that the index at these
positions matches the corresponding target values. Missing values
in the target are marked by -1.
%(raises_section)s
Examples
--------
>>> index = pd.Index(['c', 'a', 'b'])
>>> index.get_indexer(['a', 'b', 'x'])
array([ 1, 2, -1])
Notice that the return value is an array of locations in ``index``
and ``x`` is marked by -1, as it is not in ``index``.
"""
@Appender(_index_shared_docs["get_indexer"] % _index_doc_kwargs)
def get_indexer(self, target, method=None, limit=None, tolerance=None):
method = missing.clean_reindex_fill_method(method)
target = ensure_index(target)
if tolerance is not None:
tolerance = self._convert_tolerance(tolerance, target)
# Treat boolean labels passed to a numeric index as not found. Without
# this fix False and True would be treated as 0 and 1 respectively.
# (GH #16877)
if target.is_boolean() and self.is_numeric():
return ensure_platform_int(np.repeat(-1, target.size))
pself, ptarget = self._maybe_promote(target)
if pself is not self or ptarget is not target:
return pself.get_indexer(
ptarget, method=method, limit=limit, tolerance=tolerance
)
if not is_dtype_equal(self.dtype, target.dtype):
this = self.astype(object)
target = target.astype(object)
return this.get_indexer(
target, method=method, limit=limit, tolerance=tolerance
)
if not self.is_unique:
raise InvalidIndexError(
"Reindexing only valid with uniquely valued Index objects"
)
if method == "pad" or method == "backfill":
indexer = self._get_fill_indexer(target, method, limit, tolerance)
elif method == "nearest":
indexer = self._get_nearest_indexer(target, limit, tolerance)
else:
if tolerance is not None:
raise ValueError(
"tolerance argument only valid if doing pad, "
"backfill or nearest reindexing"
)
if limit is not None:
raise ValueError(
"limit argument only valid if doing pad, "
"backfill or nearest reindexing"
)
indexer = self._engine.get_indexer(target._ndarray_values)
return ensure_platform_int(indexer)
def _convert_tolerance(self, tolerance, target):
# override this method on subclasses
tolerance = np.asarray(tolerance)
if target.size != tolerance.size and tolerance.size > 1:
raise ValueError("list-like tolerance size must match target index size")
return tolerance
def _get_fill_indexer(self, target, method, limit=None, tolerance=None):
if self.is_monotonic_increasing and target.is_monotonic_increasing:
method = (
self._engine.get_pad_indexer
if method == "pad"
else self._engine.get_backfill_indexer
)
indexer = method(target._ndarray_values, limit)
else:
indexer = self._get_fill_indexer_searchsorted(target, method, limit)
if tolerance is not None:
indexer = self._filter_indexer_tolerance(
target._ndarray_values, indexer, tolerance
)
return indexer
def _get_fill_indexer_searchsorted(self, target, method, limit=None):
"""
Fallback pad/backfill get_indexer that works for monotonic decreasing
indexes and non-monotonic targets.
"""
if limit is not None:
raise ValueError(
f"limit argument for {repr(method)} method only well-defined "
"if index and target are monotonic"
)
side = "left" if method == "pad" else "right"
# find exact matches first (this simplifies the algorithm)
indexer = self.get_indexer(target)
nonexact = indexer == -1
indexer[nonexact] = self._searchsorted_monotonic(target[nonexact], side)
if side == "left":
# searchsorted returns "indices into a sorted array such that,
# if the corresponding elements in v were inserted before the
# indices, the order of a would be preserved".
# Thus, we need to subtract 1 to find values to the left.
indexer[nonexact] -= 1
# This also mapped not found values (values of 0 from
# np.searchsorted) to -1, which conveniently is also our
# sentinel for missing values
else:
# Mark indices to the right of the largest value as not found
indexer[indexer == len(self)] = -1
return indexer
def _get_nearest_indexer(self, target, limit, tolerance):
"""
Get the indexer for the nearest index labels; requires an index with
values that can be subtracted from each other (e.g., not strings or
tuples).
"""
left_indexer = self.get_indexer(target, "pad", limit=limit)
right_indexer = self.get_indexer(target, "backfill", limit=limit)
target = np.asarray(target)
left_distances = abs(self.values[left_indexer] - target)
right_distances = abs(self.values[right_indexer] - target)
op = operator.lt if self.is_monotonic_increasing else operator.le
indexer = np.where(
op(left_distances, right_distances) | (right_indexer == -1),
left_indexer,
right_indexer,
)
if tolerance is not None:
indexer = self._filter_indexer_tolerance(target, indexer, tolerance)
return indexer
def _filter_indexer_tolerance(self, target, indexer, tolerance):
distance = abs(self.values[indexer] - target)
indexer = np.where(distance <= tolerance, indexer, -1)
return indexer
# --------------------------------------------------------------------
# Indexer Conversion Methods
_index_shared_docs[
"_convert_scalar_indexer"
] = """
Convert a scalar indexer.
Parameters
----------
key : label of the slice bound
kind : {'ix', 'loc', 'getitem', 'iloc'} or None
"""
@Appender(_index_shared_docs["_convert_scalar_indexer"])
def _convert_scalar_indexer(self, key, kind=None):
assert kind in ["ix", "loc", "getitem", "iloc", None]
if kind == "iloc":
return self._validate_indexer("positional", key, kind)
if len(self) and not isinstance(self, ABCMultiIndex):
# we can raise here if we are definitive that this
# is positional indexing (eg. .ix on with a float)
# or label indexing if we are using a type able
# to be represented in the index
if kind in ["getitem", "ix"] and is_float(key):
if not self.is_floating():
return self._invalid_indexer("label", key)
elif kind in ["loc"] and is_float(key):
# we want to raise KeyError on string/mixed here
# technically we *could* raise a TypeError
# on anything but mixed though
if self.inferred_type not in [
"floating",
"mixed-integer-float",
"integer-na",
"string",
"unicode",
"mixed",
]:
self._invalid_indexer("label", key)
elif kind in ["loc"] and is_integer(key):
if not self.holds_integer():
self._invalid_indexer("label", key)
return key
_index_shared_docs[
"_convert_slice_indexer"
] = """
Convert a slice indexer.
By definition, these are labels unless 'iloc' is passed in.
Floats are not allowed as the start, step, or stop of the slice.
Parameters
----------
key : label of the slice bound
kind : {'ix', 'loc', 'getitem', 'iloc'} or None
"""
@Appender(_index_shared_docs["_convert_slice_indexer"])
def _convert_slice_indexer(self, key: slice, kind=None):
assert kind in ["ix", "loc", "getitem", "iloc", None]
# validate iloc
if kind == "iloc":
return slice(
self._validate_indexer("slice", key.start, kind),
self._validate_indexer("slice", key.stop, kind),
self._validate_indexer("slice", key.step, kind),
)
# potentially cast the bounds to integers
start, stop, step = key.start, key.stop, key.step
# figure out if this is a positional indexer
def is_int(v):
return v is None or is_integer(v)
is_null_slicer = start is None and stop is None
is_index_slice = is_int(start) and is_int(stop)
is_positional = is_index_slice and not self.is_integer()
if kind == "getitem":
"""
called from the getitem slicers, validate that we are in fact
integers
"""
if self.is_integer() or is_index_slice:
return slice(
self._validate_indexer("slice", key.start, kind),
self._validate_indexer("slice", key.stop, kind),
self._validate_indexer("slice", key.step, kind),
)
# convert the slice to an indexer here
# if we are mixed and have integers
try:
if is_positional and self.is_mixed():
# Validate start & stop
if start is not None:
self.get_loc(start)
if stop is not None:
self.get_loc(stop)
is_positional = False
except KeyError:
if self.inferred_type in ["mixed-integer-float", "integer-na"]:
raise
if is_null_slicer:
indexer = key
elif is_positional:
indexer = key
else:
indexer = self.slice_indexer(start, stop, step, kind=kind)
return indexer
def _convert_listlike_indexer(self, keyarr, kind=None):
"""
Parameters
----------
keyarr : list-like
Indexer to convert.
Returns
-------
indexer : numpy.ndarray or None
Return an ndarray or None if cannot convert.
keyarr : numpy.ndarray
Return tuple-safe keys.
"""
if isinstance(keyarr, Index):
keyarr = self._convert_index_indexer(keyarr)
else:
keyarr = self._convert_arr_indexer(keyarr)
indexer = self._convert_list_indexer(keyarr, kind=kind)
return indexer, keyarr
_index_shared_docs[
"_convert_arr_indexer"
] = """
Convert an array-like indexer to the appropriate dtype.
Parameters
----------
keyarr : array-like
Indexer to convert.
Returns
-------
converted_keyarr : array-like
"""
@Appender(_index_shared_docs["_convert_arr_indexer"])
def _convert_arr_indexer(self, keyarr):
keyarr = com.asarray_tuplesafe(keyarr)
return keyarr
_index_shared_docs[
"_convert_index_indexer"
] = """
Convert an Index indexer to the appropriate dtype.
Parameters
----------
keyarr : Index (or sub-class)
Indexer to convert.
Returns
-------
converted_keyarr : Index (or sub-class)
"""
@Appender(_index_shared_docs["_convert_index_indexer"])
def _convert_index_indexer(self, keyarr):
return keyarr
_index_shared_docs[
"_convert_list_indexer"
] = """
Convert a list-like indexer to the appropriate dtype.
Parameters
----------
keyarr : Index (or sub-class)
Indexer to convert.
kind : iloc, ix, loc, optional
Returns
-------
positional indexer or None
"""
@Appender(_index_shared_docs["_convert_list_indexer"])
def _convert_list_indexer(self, keyarr, kind=None):
if (
kind in [None, "iloc", "ix"]
and is_integer_dtype(keyarr)
and not self.is_floating()
and not isinstance(keyarr, ABCPeriodIndex)
):
if self.inferred_type == "mixed-integer":
indexer = self.get_indexer(keyarr)
if (indexer >= 0).all():
return indexer
# missing values are flagged as -1 by get_indexer and negative
# indices are already converted to positive indices in the
# above if-statement, so the negative flags are changed to
# values outside the range of indices so as to trigger an
# IndexError in maybe_convert_indices
indexer[indexer < 0] = len(self)
return maybe_convert_indices(indexer, len(self))
elif not self.inferred_type == "integer":
keyarr = np.where(keyarr < 0, len(self) + keyarr, keyarr)
return keyarr
return None
def _invalid_indexer(self, form, key):
"""
Consistent invalid indexer message.
"""
raise TypeError(
f"cannot do {form} indexing on {type(self)} with these "
f"indexers [{key}] of {type(key)}"
)
# --------------------------------------------------------------------
# Reindex Methods
def _can_reindex(self, indexer):
"""
Check if we are allowing reindexing with this particular indexer.
Parameters
----------
indexer : an integer indexer
Raises
------
ValueError if its a duplicate axis
"""
# trying to reindex on an axis with duplicates
if not self.is_unique and len(indexer):
raise ValueError("cannot reindex from a duplicate axis")
def reindex(self, target, method=None, level=None, limit=None, tolerance=None):
"""
Create index with target's values (move/add/delete values
as necessary).
Parameters
----------
target : an iterable
Returns
-------
new_index : pd.Index
Resulting index.
indexer : np.ndarray or None
Indices of output values in original index.
"""
# GH6552: preserve names when reindexing to non-named target
# (i.e. neither Index nor Series).
preserve_names = not hasattr(target, "name")
# GH7774: preserve dtype/tz if target is empty and not an Index.
target = _ensure_has_len(target) # target may be an iterator
if not isinstance(target, Index) and len(target) == 0:
attrs = self._get_attributes_dict()
attrs.pop("freq", None) # don't preserve freq
values = self._data[:0] # appropriately-dtyped empty array
target = self._simple_new(values, dtype=self.dtype, **attrs)
else:
target = ensure_index(target)
if level is not None:
if method is not None:
raise TypeError("Fill method not supported if level passed")
_, indexer, _ = self._join_level(
target, level, how="right", return_indexers=True
)
else:
if self.equals(target):
indexer = None
else:
# check is_overlapping for IntervalIndex compat
if self.is_unique and not getattr(self, "is_overlapping", False):
indexer = self.get_indexer(
target, method=method, limit=limit, tolerance=tolerance
)
else:
if method is not None or limit is not None:
raise ValueError(
"cannot reindex a non-unique index "
"with a method or limit"
)
indexer, missing = self.get_indexer_non_unique(target)
if preserve_names and target.nlevels == 1 and target.name != self.name:
target = target.copy()
target.name = self.name
return target, indexer
def _reindex_non_unique(self, target):
"""
Create a new index with target's values (move/add/delete values as
necessary) use with non-unique Index and a possibly non-unique target.
Parameters
----------
target : an iterable
Returns
-------
new_index : pd.Index
Resulting index.
indexer : np.ndarray or None
Indices of output values in original index.
"""
target = ensure_index(target)
indexer, missing = self.get_indexer_non_unique(target)
check = indexer != -1
new_labels = self.take(indexer[check])
new_indexer = None
if len(missing):
length = np.arange(len(indexer))
missing = ensure_platform_int(missing)
missing_labels = target.take(missing)
missing_indexer = ensure_int64(length[~check])
cur_labels = self.take(indexer[check]).values
cur_indexer = ensure_int64(length[check])
new_labels = np.empty(tuple([len(indexer)]), dtype=object)
new_labels[cur_indexer] = cur_labels
new_labels[missing_indexer] = missing_labels
# a unique indexer
if target.is_unique:
# see GH5553, make sure we use the right indexer
new_indexer = np.arange(len(indexer))
new_indexer[cur_indexer] = np.arange(len(cur_labels))
new_indexer[missing_indexer] = -1
# we have a non_unique selector, need to use the original
# indexer here
else:
# need to retake to have the same size as the indexer
indexer[~check] = -1
# reset the new indexer to account for the new size
new_indexer = np.arange(len(self.take(indexer)))
new_indexer[~check] = -1
new_index = self._shallow_copy_with_infer(new_labels)
return new_index, indexer, new_indexer
# --------------------------------------------------------------------
# Join Methods
_index_shared_docs[
"join"
] = """
Compute join_index and indexers to conform data
structures to the new index.
Parameters
----------
other : Index
how : {'left', 'right', 'inner', 'outer'}
level : int or level name, default None
return_indexers : bool, default False
sort : bool, default False
Sort the join keys lexicographically in the result Index. If False,
the order of the join keys depends on the join type (how keyword).
Returns
-------
join_index, (left_indexer, right_indexer)
"""
@Appender(_index_shared_docs["join"])
def join(self, other, how="left", level=None, return_indexers=False, sort=False):
self_is_mi = isinstance(self, ABCMultiIndex)
other_is_mi = isinstance(other, ABCMultiIndex)
# try to figure out the join level
# GH3662
if level is None and (self_is_mi or other_is_mi):
# have the same levels/names so a simple join
if self.names == other.names:
pass
else:
return self._join_multi(other, how=how, return_indexers=return_indexers)
# join on the level
if level is not None and (self_is_mi or other_is_mi):
return self._join_level(
other, level, how=how, return_indexers=return_indexers
)
other = ensure_index(other)
if len(other) == 0 and how in ("left", "outer"):
join_index = self._shallow_copy()
if return_indexers:
rindexer = np.repeat(-1, len(join_index))
return join_index, None, rindexer
else:
return join_index
if len(self) == 0 and how in ("right", "outer"):
join_index = other._shallow_copy()
if return_indexers:
lindexer = np.repeat(-1, len(join_index))
return join_index, lindexer, None
else:
return join_index
if self._join_precedence < other._join_precedence:
how = {"right": "left", "left": "right"}.get(how, how)
result = other.join(
self, how=how, level=level, return_indexers=return_indexers
)
if return_indexers:
x, y, z = result
result = x, z, y
return result
if not is_dtype_equal(self.dtype, other.dtype):
this = self.astype("O")
other = other.astype("O")
return this.join(other, how=how, return_indexers=return_indexers)
_validate_join_method(how)
if not self.is_unique and not other.is_unique:
return self._join_non_unique(
other, how=how, return_indexers=return_indexers
)
elif not self.is_unique or not other.is_unique:
if self.is_monotonic and other.is_monotonic:
return self._join_monotonic(
other, how=how, return_indexers=return_indexers
)
else:
return self._join_non_unique(
other, how=how, return_indexers=return_indexers
)
elif self.is_monotonic and other.is_monotonic:
try:
return self._join_monotonic(
other, how=how, return_indexers=return_indexers
)
except TypeError:
pass
if how == "left":
join_index = self
elif how == "right":
join_index = other
elif how == "inner":
# TODO: sort=False here for backwards compat. It may
# be better to use the sort parameter passed into join
join_index = self.intersection(other, sort=False)
elif how == "outer":
# TODO: sort=True here for backwards compat. It may
# be better to use the sort parameter passed into join
join_index = self.union(other)
if sort:
join_index = join_index.sort_values()
if return_indexers:
if join_index is self:
lindexer = None
else:
lindexer = self.get_indexer(join_index)
if join_index is other:
rindexer = None
else:
rindexer = other.get_indexer(join_index)
return join_index, lindexer, rindexer
else:
return join_index
def _join_multi(self, other, how, return_indexers=True):
from .multi import MultiIndex
from pandas.core.reshape.merge import _restore_dropped_levels_multijoin
# figure out join names
self_names = set(com.not_none(*self.names))
other_names = set(com.not_none(*other.names))
overlap = self_names & other_names
# need at least 1 in common
if not overlap:
raise ValueError("cannot join with no overlapping index names")
self_is_mi = isinstance(self, MultiIndex)
other_is_mi = isinstance(other, MultiIndex)
if self_is_mi and other_is_mi:
# Drop the non-matching levels from left and right respectively
ldrop_names = list(self_names - overlap)
rdrop_names = list(other_names - overlap)
self_jnlevels = self.droplevel(ldrop_names)
other_jnlevels = other.droplevel(rdrop_names)
# Join left and right
# Join on same leveled multi-index frames is supported
join_idx, lidx, ridx = self_jnlevels.join(
other_jnlevels, how, return_indexers=True
)
# Restore the dropped levels
# Returned index level order is
# common levels, ldrop_names, rdrop_names
dropped_names = ldrop_names + rdrop_names
levels, codes, names = _restore_dropped_levels_multijoin(
self, other, dropped_names, join_idx, lidx, ridx
)
# Re-create the multi-index
multi_join_idx = MultiIndex(
levels=levels, codes=codes, names=names, verify_integrity=False
)
multi_join_idx = multi_join_idx.remove_unused_levels()
return multi_join_idx, lidx, ridx
jl = list(overlap)[0]
# Case where only one index is multi
# make the indices into mi's that match
flip_order = False
if self_is_mi:
self, other = other, self
flip_order = True
# flip if join method is right or left
how = {"right": "left", "left": "right"}.get(how, how)
level = other.names.index(jl)
result = self._join_level(
other, level, how=how, return_indexers=return_indexers
)
if flip_order:
if isinstance(result, tuple):
return result[0], result[2], result[1]
return result
def _join_non_unique(self, other, how="left", return_indexers=False):
from pandas.core.reshape.merge import _get_join_indexers
left_idx, right_idx = _get_join_indexers(
[self._ndarray_values], [other._ndarray_values], how=how, sort=True
)
left_idx = ensure_platform_int(left_idx)
right_idx = ensure_platform_int(right_idx)
join_index = np.asarray(self._ndarray_values.take(left_idx))
mask = left_idx == -1
np.putmask(join_index, mask, other._ndarray_values.take(right_idx))
join_index = self._wrap_joined_index(join_index, other)
if return_indexers:
return join_index, left_idx, right_idx
else:
return join_index
def _join_level(
self, other, level, how="left", return_indexers=False, keep_order=True
):
"""
The join method *only* affects the level of the resulting
MultiIndex. Otherwise it just exactly aligns the Index data to the
labels of the level in the MultiIndex.
If ```keep_order == True```, the order of the data indexed by the
MultiIndex will not be changed; otherwise, it will tie out
with `other`.
"""
from .multi import MultiIndex
def _get_leaf_sorter(labels):
"""
Returns sorter for the inner most level while preserving the
order of higher levels.
"""
if labels[0].size == 0:
return np.empty(0, dtype="int64")
if len(labels) == 1:
lab = ensure_int64(labels[0])
sorter, _ = libalgos.groupsort_indexer(lab, 1 + lab.max())
return sorter
# find indexers of beginning of each set of
# same-key labels w.r.t all but last level
tic = labels[0][:-1] != labels[0][1:]
for lab in labels[1:-1]:
tic |= lab[:-1] != lab[1:]
starts = np.hstack(([True], tic, [True])).nonzero()[0]
lab = ensure_int64(labels[-1])
return lib.get_level_sorter(lab, ensure_int64(starts))
if isinstance(self, MultiIndex) and isinstance(other, MultiIndex):
raise TypeError("Join on level between two MultiIndex objects is ambiguous")
left, right = self, other
flip_order = not isinstance(self, MultiIndex)
if flip_order:
left, right = right, left
how = {"right": "left", "left": "right"}.get(how, how)
level = left._get_level_number(level)
old_level = left.levels[level]
if not right.is_unique:
raise NotImplementedError(
"Index._join_level on non-unique index is not implemented"
)
new_level, left_lev_indexer, right_lev_indexer = old_level.join(
right, how=how, return_indexers=True
)
if left_lev_indexer is None:
if keep_order or len(left) == 0:
left_indexer = None
join_index = left
else: # sort the leaves
left_indexer = _get_leaf_sorter(left.codes[: level + 1])
join_index = left[left_indexer]
else:
left_lev_indexer = ensure_int64(left_lev_indexer)
rev_indexer = lib.get_reverse_indexer(left_lev_indexer, len(old_level))
new_lev_codes = algos.take_nd(
rev_indexer, left.codes[level], allow_fill=False
)
new_codes = list(left.codes)
new_codes[level] = new_lev_codes
new_levels = list(left.levels)
new_levels[level] = new_level
if keep_order: # just drop missing values. o.w. keep order
left_indexer = np.arange(len(left), dtype=np.intp)
mask = new_lev_codes != -1
if not mask.all():
new_codes = [lab[mask] for lab in new_codes]
left_indexer = left_indexer[mask]
else: # tie out the order with other
if level == 0: # outer most level, take the fast route
ngroups = 1 + new_lev_codes.max()
left_indexer, counts = libalgos.groupsort_indexer(
new_lev_codes, ngroups
)
# missing values are placed first; drop them!
left_indexer = left_indexer[counts[0] :]
new_codes = [lab[left_indexer] for lab in new_codes]
else: # sort the leaves
mask = new_lev_codes != -1
mask_all = mask.all()
if not mask_all:
new_codes = [lab[mask] for lab in new_codes]
left_indexer = _get_leaf_sorter(new_codes[: level + 1])
new_codes = [lab[left_indexer] for lab in new_codes]
# left_indexers are w.r.t masked frame.
# reverse to original frame!
if not mask_all:
left_indexer = mask.nonzero()[0][left_indexer]
join_index = MultiIndex(
levels=new_levels,
codes=new_codes,
names=left.names,
verify_integrity=False,
)
if right_lev_indexer is not None:
right_indexer = algos.take_nd(
right_lev_indexer, join_index.codes[level], allow_fill=False
)
else:
right_indexer = join_index.codes[level]
if flip_order:
left_indexer, right_indexer = right_indexer, left_indexer
if return_indexers:
left_indexer = (
None if left_indexer is None else ensure_platform_int(left_indexer)
)
right_indexer = (
None if right_indexer is None else ensure_platform_int(right_indexer)
)
return join_index, left_indexer, right_indexer
else:
return join_index
def _join_monotonic(self, other, how="left", return_indexers=False):
if self.equals(other):
ret_index = other if how == "right" else self
if return_indexers:
return ret_index, None, None
else:
return ret_index
sv = self._ndarray_values
ov = other._ndarray_values
if self.is_unique and other.is_unique:
# We can perform much better than the general case
if how == "left":
join_index = self
lidx = None
ridx = self._left_indexer_unique(sv, ov)
elif how == "right":
join_index = other
lidx = self._left_indexer_unique(ov, sv)
ridx = None
elif how == "inner":
join_index, lidx, ridx = self._inner_indexer(sv, ov)
join_index = self._wrap_joined_index(join_index, other)
elif how == "outer":
join_index, lidx, ridx = self._outer_indexer(sv, ov)
join_index = self._wrap_joined_index(join_index, other)
else:
if how == "left":
join_index, lidx, ridx = self._left_indexer(sv, ov)
elif how == "right":
join_index, ridx, lidx = self._left_indexer(ov, sv)
elif how == "inner":
join_index, lidx, ridx = self._inner_indexer(sv, ov)
elif how == "outer":
join_index, lidx, ridx = self._outer_indexer(sv, ov)
join_index = self._wrap_joined_index(join_index, other)
if return_indexers:
lidx = None if lidx is None else ensure_platform_int(lidx)
ridx = None if ridx is None else ensure_platform_int(ridx)
return join_index, lidx, ridx
else:
return join_index
def _wrap_joined_index(self, joined, other):
name = get_op_result_name(self, other)
return Index(joined, name=name)
# --------------------------------------------------------------------
# Uncategorized Methods
@property
def values(self):
"""
Return an array representing the data in the Index.
.. warning::
We recommend using :attr:`Index.array` or
:meth:`Index.to_numpy`, depending on whether you need
a reference to the underlying data or a NumPy array.
Returns
-------
array: numpy.ndarray or ExtensionArray
See Also
--------
Index.array : Reference to the underlying data.
Index.to_numpy : A NumPy array representing the underlying data.
"""
return self._data.view(np.ndarray)
@property
def _values(self) -> Union[ExtensionArray, ABCIndexClass, np.ndarray]:
# TODO(EA): remove index types as they become extension arrays
"""
The best array representation.
This is an ndarray, ExtensionArray, or Index subclass. This differs
from ``_ndarray_values``, which always returns an ndarray.
Both ``_values`` and ``_ndarray_values`` are consistent between
``Series`` and ``Index``.
It may differ from the public '.values' method.
index | values | _values | _ndarray_values |
----------------- | --------------- | ------------- | --------------- |
Index | ndarray | ndarray | ndarray |
CategoricalIndex | Categorical | Categorical | ndarray[int] |
DatetimeIndex | ndarray[M8ns] | ndarray[M8ns] | ndarray[M8ns] |
DatetimeIndex[tz] | ndarray[M8ns] | DTI[tz] | ndarray[M8ns] |
PeriodIndex | ndarray[object] | PeriodArray | ndarray[int] |
IntervalIndex | IntervalArray | IntervalArray | ndarray[object] |
See Also
--------
values
_ndarray_values
"""
return self._data
def _internal_get_values(self):
"""
Return `Index` data as an `numpy.ndarray`.
Returns
-------
numpy.ndarray
A one-dimensional numpy array of the `Index` values.
See Also
--------
Index.values : The attribute that _internal_get_values wraps.
Examples
--------
Getting the `Index` values of a `DataFrame`:
>>> df = pd.DataFrame([[1, 2, 3], [4, 5, 6], [7, 8, 9]],
... index=['a', 'b', 'c'], columns=['A', 'B', 'C'])
>>> df
A B C
a 1 2 3
b 4 5 6
c 7 8 9
>>> df.index._internal_get_values()
array(['a', 'b', 'c'], dtype=object)
Standalone `Index` values:
>>> idx = pd.Index(['1', '2', '3'])
>>> idx._internal_get_values()
array(['1', '2', '3'], dtype=object)
`MultiIndex` arrays also have only one dimension:
>>> midx = pd.MultiIndex.from_arrays([[1, 2, 3], ['a', 'b', 'c']],
... names=('number', 'letter'))
>>> midx._internal_get_values()
array([(1, 'a'), (2, 'b'), (3, 'c')], dtype=object)
>>> midx._internal_get_values().ndim
1
"""
return self.values
@Appender(IndexOpsMixin.memory_usage.__doc__)
def memory_usage(self, deep=False):
result = super().memory_usage(deep=deep)
# include our engine hashtable
result += self._engine.sizeof(deep=deep)
return result
_index_shared_docs[
"where"
] = """
Return an Index of same shape as self and whose corresponding
entries are from self where cond is True and otherwise are from
other.
Parameters
----------
cond : bool array-like with the same length as self
other : scalar, or array-like
Returns
-------
Index
"""
@Appender(_index_shared_docs["where"])
def where(self, cond, other=None):
if other is None:
other = self._na_value
dtype = self.dtype
values = self.values
if is_bool(other) or is_bool_dtype(other):
# bools force casting
values = values.astype(object)
dtype = None
values = np.where(cond, values, other)
if self._is_numeric_dtype and np.any(isna(values)):
# We can't coerce to the numeric dtype of "self" (unless
# it's float) if there are NaN values in our output.
dtype = None
return self._shallow_copy_with_infer(values, dtype=dtype)
# construction helpers
@classmethod
def _try_convert_to_int_index(cls, data, copy, name, dtype):
"""
Attempt to convert an array of data into an integer index.
Parameters
----------
data : The data to convert.
copy : Whether to copy the data or not.
name : The name of the index returned.
Returns
-------
int_index : data converted to either an Int64Index or a
UInt64Index
Raises
------
ValueError if the conversion was not successful.
"""
from .numeric import Int64Index, UInt64Index
if not is_unsigned_integer_dtype(dtype):
# skip int64 conversion attempt if uint-like dtype is passed, as
# this could return Int64Index when UInt64Index is what's desired
try:
res = data.astype("i8", copy=False)
if (res == data).all():
return Int64Index(res, copy=copy, name=name)
except (OverflowError, TypeError, ValueError):
pass
# Conversion to int64 failed (possibly due to overflow) or was skipped,
# so let's try now with uint64.
try:
res = data.astype("u8", copy=False)
if (res == data).all():
return UInt64Index(res, copy=copy, name=name)
except (OverflowError, TypeError, ValueError):
pass
raise ValueError
@classmethod
def _scalar_data_error(cls, data):
# We return the TypeError so that we can raise it from the constructor
# in order to keep mypy happy
return TypeError(
f"{cls.__name__}(...) must be called with a collection of some "
f"kind, {repr(data)} was passed"
)
@classmethod
def _string_data_error(cls, data):
raise TypeError(
"String dtype not supported, you may need "
"to explicitly cast to a numeric type"
)
def _coerce_scalar_to_index(self, item):
"""
We need to coerce a scalar to a compat for our index type.
Parameters
----------
item : scalar item to coerce
"""
dtype = self.dtype
if self._is_numeric_dtype and isna(item):
# We can't coerce to the numeric dtype of "self" (unless
# it's float) if there are NaN values in our output.
dtype = None
return Index([item], dtype=dtype, **self._get_attributes_dict())
def _to_safe_for_reshape(self):
"""
Convert to object if we are a categorical.
"""
return self
def _convert_for_op(self, value):
"""
Convert value to be insertable to ndarray.
"""
return value
def _assert_can_do_op(self, value):
"""
Check value is valid for scalar op.
"""
if not is_scalar(value):
raise TypeError(f"'value' must be a scalar, passed: {type(value).__name__}")
def _is_memory_usage_qualified(self) -> bool:
"""
Return a boolean if we need a qualified .info display.
"""
return self.is_object()
def is_type_compatible(self, kind) -> bool:
"""
Whether the index type is compatible with the provided type.
"""
return kind == self.inferred_type
_index_shared_docs[
"contains"
] = """
Return a boolean indicating whether the provided key is in the index.
Parameters
----------
key : label
The key to check if it is present in the index.
Returns
-------
bool
Whether the key search is in the index.
See Also
--------
Index.isin : Returns an ndarray of boolean dtype indicating whether the
list-like key is in the index.
Examples
--------
>>> idx = pd.Index([1, 2, 3, 4])
>>> idx
Int64Index([1, 2, 3, 4], dtype='int64')
>>> 2 in idx
True
>>> 6 in idx
False
"""
@Appender(_index_shared_docs["contains"] % _index_doc_kwargs)
def __contains__(self, key) -> bool:
hash(key)
try:
return key in self._engine
except (OverflowError, TypeError, ValueError):
return False
def __hash__(self):
raise TypeError(f"unhashable type: {repr(type(self).__name__)}")
def __setitem__(self, key, value):
raise TypeError("Index does not support mutable operations")
def __getitem__(self, key):
"""
Override numpy.ndarray's __getitem__ method to work as desired.
This function adds lists and Series as valid boolean indexers
(ndarrays only supports ndarray with dtype=bool).
If resulting ndim != 1, plain ndarray is returned instead of
corresponding `Index` subclass.
"""
# There's no custom logic to be implemented in __getslice__, so it's
# not overloaded intentionally.
getitem = self._data.__getitem__
promote = self._shallow_copy
if is_scalar(key):
key = com.cast_scalar_indexer(key)
return getitem(key)
if isinstance(key, slice):
# This case is separated from the conditional above to avoid
# pessimization of basic indexing.
return promote(getitem(key))
if com.is_bool_indexer(key):
key = np.asarray(key, dtype=bool)
key = com.values_from_object(key)
result = getitem(key)
if not is_scalar(result):
return promote(result)
else:
return result
def _can_hold_identifiers_and_holds_name(self, name) -> bool:
"""
Faster check for ``name in self`` when we know `name` is a Python
identifier (e.g. in NDFrame.__getattr__, which hits this to support
. key lookup). For indexes that can't hold identifiers (everything
but object & categorical) we just return False.
https://github.com/pandas-dev/pandas/issues/19764
"""
if self.is_object() or self.is_categorical():
return name in self
return False
def append(self, other):
"""
Append a collection of Index options together.
Parameters
----------
other : Index or list/tuple of indices
Returns
-------
appended : Index
"""
to_concat = [self]
if isinstance(other, (list, tuple)):
to_concat = to_concat + list(other)
else:
to_concat.append(other)
for obj in to_concat:
if not isinstance(obj, Index):
raise TypeError("all inputs must be Index")
names = {obj.name for obj in to_concat}
name = None if len(names) > 1 else self.name
return self._concat(to_concat, name)
def _concat(self, to_concat, name):
typs = _concat.get_dtype_kinds(to_concat)
if len(typs) == 1:
return self._concat_same_dtype(to_concat, name=name)
return Index._concat_same_dtype(self, to_concat, name=name)
def _concat_same_dtype(self, to_concat, name):
"""
Concatenate to_concat which has the same class.
"""
# must be overridden in specific classes
klasses = (
ABCDatetimeIndex,
ABCTimedeltaIndex,
ABCPeriodIndex,
ExtensionArray,
ABCIntervalIndex,
)
to_concat = [
x.astype(object) if isinstance(x, klasses) else x for x in to_concat
]
self = to_concat[0]
attribs = self._get_attributes_dict()
attribs["name"] = name
to_concat = [x._values if isinstance(x, Index) else x for x in to_concat]
return self._shallow_copy_with_infer(np.concatenate(to_concat), **attribs)
def putmask(self, mask, value):
"""
Return a new Index of the values set with the mask.
Returns
-------
Index
See Also
--------
numpy.ndarray.putmask
"""
values = self.values.copy()
try:
np.putmask(values, mask, self._convert_for_op(value))
return self._shallow_copy(values)
except (ValueError, TypeError) as err:
if is_object_dtype(self):
raise err
# coerces to object
return self.astype(object).putmask(mask, value)
def equals(self, other) -> bool:
"""
Determine if two Index objects contain the same elements.
Returns
-------
bool
True if "other" is an Index and it has the same elements as calling
index; False otherwise.
"""
if self.is_(other):
return True
if not isinstance(other, Index):
return False
if is_object_dtype(self) and not is_object_dtype(other):
# if other is not object, use other's logic for coercion
return other.equals(self)
if isinstance(other, ABCMultiIndex):
# d-level MultiIndex can equal d-tuple Index
if not is_object_dtype(self.dtype):
if self.nlevels != other.nlevels:
return False
return array_equivalent(
com.values_from_object(self), com.values_from_object(other)
)
def identical(self, other) -> bool:
"""
Similar to equals, but check that other comparable attributes are
also equal.
Returns
-------
bool
If two Index objects have equal elements and same type True,
otherwise False.
"""
return (
self.equals(other)
and all(
(
getattr(self, c, None) == getattr(other, c, None)
for c in self._comparables
)
)
and type(self) == type(other)
)
def asof(self, label):
"""
Return the label from the index, or, if not present, the previous one.
Assuming that the index is sorted, return the passed index label if it
is in the index, or return the previous index label if the passed one
is not in the index.
Parameters
----------
label : object
The label up to which the method returns the latest index label.
Returns
-------
object
The passed label if it is in the index. The previous label if the
passed label is not in the sorted index or `NaN` if there is no
such label.
See Also
--------
Series.asof : Return the latest value in a Series up to the
passed index.
merge_asof : Perform an asof merge (similar to left join but it
matches on nearest key rather than equal key).
Index.get_loc : An `asof` is a thin wrapper around `get_loc`
with method='pad'.
Examples
--------
`Index.asof` returns the latest index label up to the passed label.
>>> idx = pd.Index(['2013-12-31', '2014-01-02', '2014-01-03'])
>>> idx.asof('2014-01-01')
'2013-12-31'
If the label is in the index, the method returns the passed label.
>>> idx.asof('2014-01-02')
'2014-01-02'
If all of the labels in the index are later than the passed label,
NaN is returned.
>>> idx.asof('1999-01-02')
nan
If the index is not sorted, an error is raised.
>>> idx_not_sorted = pd.Index(['2013-12-31', '2015-01-02',
... '2014-01-03'])
>>> idx_not_sorted.asof('2013-12-31')
Traceback (most recent call last):
ValueError: index must be monotonic increasing or decreasing
"""
try:
loc = self.get_loc(label, method="pad")
except KeyError:
return self._na_value
else:
if isinstance(loc, slice):
loc = loc.indices(len(self))[-1]
return self[loc]
def asof_locs(self, where, mask):
"""
Find the locations (indices) of the labels from the index for
every entry in the `where` argument.
As in the `asof` function, if the label (a particular entry in
`where`) is not in the index, the latest index label up to the
passed label is chosen and its index returned.
If all of the labels in the index are later than a label in `where`,
-1 is returned.
`mask` is used to ignore NA values in the index during calculation.
Parameters
----------
where : Index
An Index consisting of an array of timestamps.
mask : array-like
Array of booleans denoting where values in the original
data are not NA.
Returns
-------
numpy.ndarray
An array of locations (indices) of the labels from the Index
which correspond to the return values of the `asof` function
for every element in `where`.
"""
locs = self.values[mask].searchsorted(where.values, side="right")
locs = np.where(locs > 0, locs - 1, 0)
result = np.arange(len(self))[mask].take(locs)
first = mask.argmax()
result[(locs == 0) & (where.values < self.values[first])] = -1
return result
def sort_values(self, return_indexer=False, ascending=True):
"""
Return a sorted copy of the index.
Return a sorted copy of the index, and optionally return the indices
that sorted the index itself.
Parameters
----------
return_indexer : bool, default False
Should the indices that would sort the index be returned.
ascending : bool, default True
Should the index values be sorted in an ascending order.
Returns
-------
sorted_index : pandas.Index
Sorted copy of the index.
indexer : numpy.ndarray, optional
The indices that the index itself was sorted by.
See Also
--------
Series.sort_values : Sort values of a Series.
DataFrame.sort_values : Sort values in a DataFrame.
Examples
--------
>>> idx = pd.Index([10, 100, 1, 1000])
>>> idx
Int64Index([10, 100, 1, 1000], dtype='int64')
Sort values in ascending order (default behavior).
>>> idx.sort_values()
Int64Index([1, 10, 100, 1000], dtype='int64')
Sort values in descending order, and also get the indices `idx` was
sorted by.
>>> idx.sort_values(ascending=False, return_indexer=True)
(Int64Index([1000, 100, 10, 1], dtype='int64'), array([3, 1, 0, 2]))
"""
_as = self.argsort()
if not ascending:
_as = _as[::-1]
sorted_index = self.take(_as)
if return_indexer:
return sorted_index, _as
else:
return sorted_index
def sort(self, *args, **kwargs):
"""
Use sort_values instead.
"""
raise TypeError("cannot sort an Index object in-place, use sort_values instead")
def shift(self, periods=1, freq=None):
"""
Shift index by desired number of time frequency increments.
This method is for shifting the values of datetime-like indexes
by a specified time increment a given number of times.
Parameters
----------
periods : int, default 1
Number of periods (or increments) to shift by,
can be positive or negative.
freq : pandas.DateOffset, pandas.Timedelta or str, optional
Frequency increment to shift by.
If None, the index is shifted by its own `freq` attribute.
Offset aliases are valid strings, e.g., 'D', 'W', 'M' etc.
Returns
-------
pandas.Index
Shifted index.
See Also
--------
Series.shift : Shift values of Series.
Notes
-----
This method is only implemented for datetime-like index classes,
i.e., DatetimeIndex, PeriodIndex and TimedeltaIndex.
Examples
--------
Put the first 5 month starts of 2011 into an index.
>>> month_starts = pd.date_range('1/1/2011', periods=5, freq='MS')
>>> month_starts
DatetimeIndex(['2011-01-01', '2011-02-01', '2011-03-01', '2011-04-01',
'2011-05-01'],
dtype='datetime64[ns]', freq='MS')
Shift the index by 10 days.
>>> month_starts.shift(10, freq='D')
DatetimeIndex(['2011-01-11', '2011-02-11', '2011-03-11', '2011-04-11',
'2011-05-11'],
dtype='datetime64[ns]', freq=None)
The default value of `freq` is the `freq` attribute of the index,
which is 'MS' (month start) in this example.
>>> month_starts.shift(10)
DatetimeIndex(['2011-11-01', '2011-12-01', '2012-01-01', '2012-02-01',
'2012-03-01'],
dtype='datetime64[ns]', freq='MS')
"""
raise NotImplementedError(f"Not supported for type {type(self).__name__}")
def argsort(self, *args, **kwargs):
"""
Return the integer indices that would sort the index.
Parameters
----------
*args
Passed to `numpy.ndarray.argsort`.
**kwargs
Passed to `numpy.ndarray.argsort`.
Returns
-------
numpy.ndarray
Integer indices that would sort the index if used as
an indexer.
See Also
--------
numpy.argsort : Similar method for NumPy arrays.
Index.sort_values : Return sorted copy of Index.
Examples
--------
>>> idx = pd.Index(['b', 'a', 'd', 'c'])
>>> idx
Index(['b', 'a', 'd', 'c'], dtype='object')
>>> order = idx.argsort()
>>> order
array([1, 0, 3, 2])
>>> idx[order]
Index(['a', 'b', 'c', 'd'], dtype='object')
"""
result = self.asi8
if result is None:
result = np.array(self)
return result.argsort(*args, **kwargs)
_index_shared_docs[
"get_value"
] = """
Fast lookup of value from 1-dimensional ndarray. Only use this if you
know what you're doing.
Returns
-------
scalar
A value in the Series with the index of the key value in self.
"""
@Appender(_index_shared_docs["get_value"] % _index_doc_kwargs)
def get_value(self, series, key):
# if we have something that is Index-like, then
# use this, e.g. DatetimeIndex
# Things like `Series._get_value` (via .at) pass the EA directly here.
s = extract_array(series, extract_numpy=True)
if isinstance(s, ExtensionArray):
if is_scalar(key):
# GH 20882, 21257
# First try to convert the key to a location
# If that fails, raise a KeyError if an integer
# index, otherwise, see if key is an integer, and
# try that
try:
iloc = self.get_loc(key)
return s[iloc]
except KeyError:
if len(self) > 0 and (self.holds_integer() or self.is_boolean()):
raise
elif is_integer(key):
return s[key]
else:
# if key is not a scalar, directly raise an error (the code below
# would convert to numpy arrays and raise later any way) - GH29926
raise InvalidIndexError(key)
s = com.values_from_object(series)
k = com.values_from_object(key)
k = self._convert_scalar_indexer(k, kind="getitem")
try:
return self._engine.get_value(s, k, tz=getattr(series.dtype, "tz", None))
except KeyError as e1:
if len(self) > 0 and (self.holds_integer() or self.is_boolean()):
raise
try:
return libindex.get_value_at(s, key)
except IndexError:
raise
except TypeError:
# generator/iterator-like
if is_iterator(key):
raise InvalidIndexError(key)
else:
raise e1
except Exception:
raise e1
except TypeError:
# e.g. "[False] is an invalid key"
if is_scalar(key):
raise IndexError(key)
raise InvalidIndexError(key)
def set_value(self, arr, key, value):
"""
Fast lookup of value from 1-dimensional ndarray.
.. deprecated:: 1.0
Notes
-----
Only use this if you know what you're doing.
"""
warnings.warn(
(
"The 'set_value' method is deprecated, and "
"will be removed in a future version."
),
FutureWarning,
stacklevel=2,
)
self._engine.set_value(
com.values_from_object(arr), com.values_from_object(key), value
)
_index_shared_docs[
"get_indexer_non_unique"
] = """
Compute indexer and mask for new index given the current index. The
indexer should be then used as an input to ndarray.take to align the
current data to the new index.
Parameters
----------
target : %(target_klass)s
Returns
-------
indexer : ndarray of int
Integers from 0 to n - 1 indicating that the index at these
positions matches the corresponding target values. Missing values
in the target are marked by -1.
missing : ndarray of int
An indexer into the target of the values not found.
These correspond to the -1 in the indexer array.
"""
@Appender(_index_shared_docs["get_indexer_non_unique"] % _index_doc_kwargs)
def get_indexer_non_unique(self, target):
target = ensure_index(target)
pself, ptarget = self._maybe_promote(target)
if pself is not self or ptarget is not target:
return pself.get_indexer_non_unique(ptarget)
if is_categorical(target):
tgt_values = np.asarray(target)
elif self.is_all_dates:
tgt_values = target.asi8
else:
tgt_values = target._ndarray_values
indexer, missing = self._engine.get_indexer_non_unique(tgt_values)
return ensure_platform_int(indexer), missing
def get_indexer_for(self, target, **kwargs):
"""
Guaranteed return of an indexer even when non-unique.
This dispatches to get_indexer or get_indexer_non_unique
as appropriate.
Returns
-------
numpy.ndarray
List of indices.
"""
if self.is_unique:
return self.get_indexer(target, **kwargs)
indexer, _ = self.get_indexer_non_unique(target, **kwargs)
return indexer
def _maybe_promote(self, other):
# A hack, but it works
if self.inferred_type == "date" and isinstance(other, ABCDatetimeIndex):
return type(other)(self), other
elif self.inferred_type == "boolean":
if not is_object_dtype(self.dtype):
return self.astype("object"), other.astype("object")
return self, other
def groupby(self, values):
"""
Group the index labels by a given array of values.
Parameters
----------
values : array
Values used to determine the groups.
Returns
-------
groups : dict
{group name -> group labels}
"""
# TODO: if we are a MultiIndex, we can do better
# that converting to tuples
if isinstance(values, ABCMultiIndex):
values = values.values
values = ensure_categorical(values)
result = values._reverse_indexer()
# map to the label
result = {k: self.take(v) for k, v in result.items()}
return result
def map(self, mapper, na_action=None):
"""
Map values using input correspondence (a dict, Series, or function).
Parameters
----------
mapper : function, dict, or Series
Mapping correspondence.
na_action : {None, 'ignore'}
If 'ignore', propagate NA values, without passing them to the
mapping correspondence.
Returns
-------
applied : Union[Index, MultiIndex], inferred
The output of the mapping function applied to the index.
If the function returns a tuple with more than one element
a MultiIndex will be returned.
"""
from .multi import MultiIndex
new_values = super()._map_values(mapper, na_action=na_action)
attributes = self._get_attributes_dict()
# we can return a MultiIndex
if new_values.size and isinstance(new_values[0], tuple):
if isinstance(self, MultiIndex):
names = self.names
elif attributes.get("name"):
names = [attributes.get("name")] * len(new_values[0])
else:
names = None
return MultiIndex.from_tuples(new_values, names=names)
attributes["copy"] = False
if not new_values.size:
# empty
attributes["dtype"] = self.dtype
return Index(new_values, **attributes)
def isin(self, values, level=None):
"""
Return a boolean array where the index values are in `values`.
Compute boolean array of whether each index value is found in the
passed set of values. The length of the returned boolean array matches
the length of the index.
Parameters
----------
values : set or list-like
Sought values.
level : str or int, optional
Name or position of the index level to use (if the index is a
`MultiIndex`).
Returns
-------
is_contained : ndarray
NumPy array of boolean values.
See Also
--------
Series.isin : Same for Series.
DataFrame.isin : Same method for DataFrames.
Notes
-----
In the case of `MultiIndex` you must either specify `values` as a
list-like object containing tuples that are the same length as the
number of levels, or specify `level`. Otherwise it will raise a
``ValueError``.
If `level` is specified:
- if it is the name of one *and only one* index level, use that level;
- otherwise it should be a number indicating level position.
Examples
--------
>>> idx = pd.Index([1,2,3])
>>> idx
Int64Index([1, 2, 3], dtype='int64')
Check whether each index value in a list of values.
>>> idx.isin([1, 4])
array([ True, False, False])
>>> midx = pd.MultiIndex.from_arrays([[1,2,3],
... ['red', 'blue', 'green']],
... names=('number', 'color'))
>>> midx
MultiIndex(levels=[[1, 2, 3], ['blue', 'green', 'red']],
codes=[[0, 1, 2], [2, 0, 1]],
names=['number', 'color'])
Check whether the strings in the 'color' level of the MultiIndex
are in a list of colors.
>>> midx.isin(['red', 'orange', 'yellow'], level='color')
array([ True, False, False])
To check across the levels of a MultiIndex, pass a list of tuples:
>>> midx.isin([(1, 'red'), (3, 'red')])
array([ True, False, False])
For a DatetimeIndex, string values in `values` are converted to
Timestamps.
>>> dates = ['2000-03-11', '2000-03-12', '2000-03-13']
>>> dti = pd.to_datetime(dates)
>>> dti
DatetimeIndex(['2000-03-11', '2000-03-12', '2000-03-13'],
dtype='datetime64[ns]', freq=None)
>>> dti.isin(['2000-03-11'])
array([ True, False, False])
"""
if level is not None:
self._validate_index_level(level)
return algos.isin(self, values)
def _get_string_slice(self, key, use_lhs=True, use_rhs=True):
# this is for partial string indexing,
# overridden in DatetimeIndex, TimedeltaIndex and PeriodIndex
raise NotImplementedError
def slice_indexer(self, start=None, end=None, step=None, kind=None):
"""
For an ordered or unique index, compute the slice indexer for input
labels and step.
Parameters
----------
start : label, default None
If None, defaults to the beginning.
end : label, default None
If None, defaults to the end.
step : int, default None
kind : str, default None
Returns
-------
indexer : slice
Raises
------
KeyError : If key does not exist, or key is not unique and index is
not ordered.
Notes
-----
This function assumes that the data is sorted, so use at your own peril
Examples
--------
This is a method on all index types. For example you can do:
>>> idx = pd.Index(list('abcd'))
>>> idx.slice_indexer(start='b', end='c')
slice(1, 3)
>>> idx = pd.MultiIndex.from_arrays([list('abcd'), list('efgh')])
>>> idx.slice_indexer(start='b', end=('c', 'g'))
slice(1, 3)
"""
start_slice, end_slice = self.slice_locs(start, end, step=step, kind=kind)
# return a slice
if not is_scalar(start_slice):
raise AssertionError("Start slice bound is non-scalar")
if not is_scalar(end_slice):
raise AssertionError("End slice bound is non-scalar")
return slice(start_slice, end_slice, step)
def _maybe_cast_indexer(self, key):
"""
If we have a float key and are not a floating index, then try to cast
to an int if equivalent.
"""
if is_float(key) and not self.is_floating():
try:
ckey = int(key)
if ckey == key:
key = ckey
except (OverflowError, ValueError, TypeError):
pass
return key
def _validate_indexer(self, form, key, kind):
"""
If we are positional indexer, validate that we have appropriate
typed bounds must be an integer.
"""
assert kind in ["ix", "loc", "getitem", "iloc"]
if key is None:
pass
elif is_integer(key):
pass
elif kind in ["iloc", "getitem"]:
self._invalid_indexer(form, key)
return key
_index_shared_docs[
"_maybe_cast_slice_bound"
] = """
This function should be overloaded in subclasses that allow non-trivial
casting on label-slice bounds, e.g. datetime-like indices allowing
strings containing formatted datetimes.
Parameters
----------
label : object
side : {'left', 'right'}
kind : {'ix', 'loc', 'getitem'}
Returns
-------
label : object
Notes
-----
Value of `side` parameter should be validated in caller.
"""
@Appender(_index_shared_docs["_maybe_cast_slice_bound"])
def _maybe_cast_slice_bound(self, label, side, kind):
assert kind in ["ix", "loc", "getitem", None]
# We are a plain index here (sub-class override this method if they
# wish to have special treatment for floats/ints, e.g. Float64Index and
# datetimelike Indexes
# reject them
if is_float(label):
if not (kind in ["ix"] and (self.holds_integer() or self.is_floating())):
self._invalid_indexer("slice", label)
# we are trying to find integer bounds on a non-integer based index
# this is rejected (generally .loc gets you here)
elif is_integer(label):
self._invalid_indexer("slice", label)
return label
def _searchsorted_monotonic(self, label, side="left"):
if self.is_monotonic_increasing:
return self.searchsorted(label, side=side)
elif self.is_monotonic_decreasing:
# np.searchsorted expects ascending sort order, have to reverse
# everything for it to work (element ordering, search side and
# resulting value).
pos = self[::-1].searchsorted(
label, side="right" if side == "left" else "left"
)
return len(self) - pos
raise ValueError("index must be monotonic increasing or decreasing")
def get_slice_bound(self, label, side, kind):
"""
Calculate slice bound that corresponds to given label.
Returns leftmost (one-past-the-rightmost if ``side=='right'``) position
of given label.
Parameters
----------
label : object
side : {'left', 'right'}
kind : {'ix', 'loc', 'getitem'}
Returns
-------
int
Index of label.
"""
assert kind in ["ix", "loc", "getitem", None]
if side not in ("left", "right"):
raise ValueError(
f"Invalid value for side kwarg, must be either"
f" 'left' or 'right': {side}"
)
original_label = label
# For datetime indices label may be a string that has to be converted
# to datetime boundary according to its resolution.
label = self._maybe_cast_slice_bound(label, side, kind)
# we need to look up the label
try:
slc = self.get_loc(label)
except KeyError as err:
try:
return self._searchsorted_monotonic(label, side)
except ValueError:
# raise the original KeyError
raise err
if isinstance(slc, np.ndarray):
# get_loc may return a boolean array or an array of indices, which
# is OK as long as they are representable by a slice.
if is_bool_dtype(slc):
slc = lib.maybe_booleans_to_slice(slc.view("u1"))
else:
slc = lib.maybe_indices_to_slice(slc.astype("i8"), len(self))
if isinstance(slc, np.ndarray):
raise KeyError(
f"Cannot get {side} slice bound for non-unique "
f"label: {repr(original_label)}"
)
if isinstance(slc, slice):
if side == "left":
return slc.start
else:
return slc.stop
else:
if side == "right":
return slc + 1
else:
return slc
def slice_locs(self, start=None, end=None, step=None, kind=None):
"""
Compute slice locations for input labels.
Parameters
----------
start : label, default None
If None, defaults to the beginning.
end : label, default None
If None, defaults to the end.
step : int, defaults None
If None, defaults to 1.
kind : {'ix', 'loc', 'getitem'} or None
Returns
-------
start, end : int
See Also
--------
Index.get_loc : Get location for a single label.
Notes
-----
This method only works if the index is monotonic or unique.
Examples
--------
>>> idx = pd.Index(list('abcd'))
>>> idx.slice_locs(start='b', end='c')
(1, 3)
"""
inc = step is None or step >= 0
if not inc:
# If it's a reverse slice, temporarily swap bounds.
start, end = end, start
# GH 16785: If start and end happen to be date strings with UTC offsets
# attempt to parse and check that the offsets are the same
if isinstance(start, (str, datetime)) and isinstance(end, (str, datetime)):
try:
ts_start = Timestamp(start)
ts_end = Timestamp(end)
except (ValueError, TypeError):
pass
else:
if not tz_compare(ts_start.tzinfo, ts_end.tzinfo):
raise ValueError("Both dates must have the same UTC offset")
start_slice = None
if start is not None:
start_slice = self.get_slice_bound(start, "left", kind)
if start_slice is None:
start_slice = 0
end_slice = None
if end is not None:
end_slice = self.get_slice_bound(end, "right", kind)
if end_slice is None:
end_slice = len(self)
if not inc:
# Bounds at this moment are swapped, swap them back and shift by 1.
#
# slice_locs('B', 'A', step=-1): s='B', e='A'
#
# s='A' e='B'
# AFTER SWAP: | |
# v ------------------> V
# -----------------------------------
# | | |A|A|A|A| | | | | |B|B| | | | |
# -----------------------------------
# ^ <------------------ ^
# SHOULD BE: | |
# end=s-1 start=e-1
#
end_slice, start_slice = start_slice - 1, end_slice - 1
# i == -1 triggers ``len(self) + i`` selection that points to the
# last element, not before-the-first one, subtracting len(self)
# compensates that.
if end_slice == -1:
end_slice -= len(self)
if start_slice == -1:
start_slice -= len(self)
return start_slice, end_slice
def delete(self, loc):
"""
Make new Index with passed location(-s) deleted.
Returns
-------
new_index : Index
"""
return self._shallow_copy(np.delete(self._data, loc))
def insert(self, loc, item):
"""
Make new Index inserting new item at location.
Follows Python list.append semantics for negative values.
Parameters
----------
loc : int
item : object
Returns
-------
new_index : Index
"""
_self = np.asarray(self)
item = self._coerce_scalar_to_index(item)._ndarray_values
idx = np.concatenate((_self[:loc], item, _self[loc:]))
return self._shallow_copy_with_infer(idx)
def drop(self, labels, errors="raise"):
"""
Make new Index with passed list of labels deleted.
Parameters
----------
labels : array-like
errors : {'ignore', 'raise'}, default 'raise'
If 'ignore', suppress error and existing labels are dropped.
Returns
-------
dropped : Index
Raises
------
KeyError
If not all of the labels are found in the selected axis
"""
arr_dtype = "object" if self.dtype == "object" else None
labels = com.index_labels_to_array(labels, dtype=arr_dtype)
indexer = self.get_indexer(labels)
mask = indexer == -1
if mask.any():
if errors != "ignore":
raise KeyError(f"{labels[mask]} not found in axis")
indexer = indexer[~mask]
return self.delete(indexer)
# --------------------------------------------------------------------
# Generated Arithmetic, Comparison, and Unary Methods
@classmethod
def _add_comparison_methods(cls):
"""
Add in comparison methods.
"""
cls.__eq__ = _make_comparison_op(operator.eq, cls)
cls.__ne__ = _make_comparison_op(operator.ne, cls)
cls.__lt__ = _make_comparison_op(operator.lt, cls)
cls.__gt__ = _make_comparison_op(operator.gt, cls)
cls.__le__ = _make_comparison_op(operator.le, cls)
cls.__ge__ = _make_comparison_op(operator.ge, cls)
@classmethod
def _add_numeric_methods_add_sub_disabled(cls):
"""
Add in the numeric add/sub methods to disable.
"""
cls.__add__ = make_invalid_op("__add__")
cls.__radd__ = make_invalid_op("__radd__")
cls.__iadd__ = make_invalid_op("__iadd__")
cls.__sub__ = make_invalid_op("__sub__")
cls.__rsub__ = make_invalid_op("__rsub__")
cls.__isub__ = make_invalid_op("__isub__")
@classmethod
def _add_numeric_methods_disabled(cls):
"""
Add in numeric methods to disable other than add/sub.
"""
cls.__pow__ = make_invalid_op("__pow__")
cls.__rpow__ = make_invalid_op("__rpow__")
cls.__mul__ = make_invalid_op("__mul__")
cls.__rmul__ = make_invalid_op("__rmul__")
cls.__floordiv__ = make_invalid_op("__floordiv__")
cls.__rfloordiv__ = make_invalid_op("__rfloordiv__")
cls.__truediv__ = make_invalid_op("__truediv__")
cls.__rtruediv__ = make_invalid_op("__rtruediv__")
cls.__mod__ = make_invalid_op("__mod__")
cls.__divmod__ = make_invalid_op("__divmod__")
cls.__neg__ = make_invalid_op("__neg__")
cls.__pos__ = make_invalid_op("__pos__")
cls.__abs__ = make_invalid_op("__abs__")
cls.__inv__ = make_invalid_op("__inv__")
@classmethod
def _add_numeric_methods_binary(cls):
"""
Add in numeric methods.
"""
cls.__add__ = _make_arithmetic_op(operator.add, cls)
cls.__radd__ = _make_arithmetic_op(ops.radd, cls)
cls.__sub__ = _make_arithmetic_op(operator.sub, cls)
cls.__rsub__ = _make_arithmetic_op(ops.rsub, cls)
cls.__rpow__ = _make_arithmetic_op(ops.rpow, cls)
cls.__pow__ = _make_arithmetic_op(operator.pow, cls)
cls.__truediv__ = _make_arithmetic_op(operator.truediv, cls)
cls.__rtruediv__ = _make_arithmetic_op(ops.rtruediv, cls)
# TODO: rmod? rdivmod?
cls.__mod__ = _make_arithmetic_op(operator.mod, cls)
cls.__floordiv__ = _make_arithmetic_op(operator.floordiv, cls)
cls.__rfloordiv__ = _make_arithmetic_op(ops.rfloordiv, cls)
cls.__divmod__ = _make_arithmetic_op(divmod, cls)
cls.__mul__ = _make_arithmetic_op(operator.mul, cls)
cls.__rmul__ = _make_arithmetic_op(ops.rmul, cls)
@classmethod
def _add_numeric_methods_unary(cls):
"""
Add in numeric unary methods.
"""
def _make_evaluate_unary(op, opstr):
def _evaluate_numeric_unary(self):
attrs = self._get_attributes_dict()
return Index(op(self.values), **attrs)
_evaluate_numeric_unary.__name__ = opstr
return _evaluate_numeric_unary
cls.__neg__ = _make_evaluate_unary(operator.neg, "__neg__")
cls.__pos__ = _make_evaluate_unary(operator.pos, "__pos__")
cls.__abs__ = _make_evaluate_unary(np.abs, "__abs__")
cls.__inv__ = _make_evaluate_unary(lambda x: -x, "__inv__")
@classmethod
def _add_numeric_methods(cls):
cls._add_numeric_methods_unary()
cls._add_numeric_methods_binary()
@classmethod
def _add_logical_methods(cls):
"""
Add in logical methods.
"""
_doc = """
%(desc)s
Parameters
----------
*args
These parameters will be passed to numpy.%(outname)s.
**kwargs
These parameters will be passed to numpy.%(outname)s.
Returns
-------
%(outname)s : bool or array_like (if axis is specified)
A single element array_like may be converted to bool."""
_index_shared_docs["index_all"] = dedent(
"""
See Also
--------
Index.any : Return whether any element in an Index is True.
Series.any : Return whether any element in a Series is True.
Series.all : Return whether all elements in a Series are True.
Notes
-----
Not a Number (NaN), positive infinity and negative infinity
evaluate to True because these are not equal to zero.
Examples
--------
**all**
True, because nonzero integers are considered True.
>>> pd.Index([1, 2, 3]).all()
True
False, because ``0`` is considered False.
>>> pd.Index([0, 1, 2]).all()
False
**any**
True, because ``1`` is considered True.
>>> pd.Index([0, 0, 1]).any()
True
False, because ``0`` is considered False.
>>> pd.Index([0, 0, 0]).any()
False
"""
)
_index_shared_docs["index_any"] = dedent(
"""
See Also
--------
Index.all : Return whether all elements are True.
Series.all : Return whether all elements are True.
Notes
-----
Not a Number (NaN), positive infinity and negative infinity
evaluate to True because these are not equal to zero.
Examples
--------
>>> index = pd.Index([0, 1, 2])
>>> index.any()
True
>>> index = pd.Index([0, 0, 0])
>>> index.any()
False
"""
)
def _make_logical_function(name, desc, f):
@Substitution(outname=name, desc=desc)
@Appender(_index_shared_docs["index_" + name])
@Appender(_doc)
def logical_func(self, *args, **kwargs):
result = f(self.values)
if (
isinstance(result, (np.ndarray, ABCSeries, Index))
and result.ndim == 0
):
# return NumPy type
return result.dtype.type(result.item())
else: # pragma: no cover
return result
logical_func.__name__ = name
return logical_func
cls.all = _make_logical_function(
"all", "Return whether all elements are True.", np.all
)
cls.any = _make_logical_function(
"any", "Return whether any element is True.", np.any
)
@classmethod
def _add_logical_methods_disabled(cls):
"""
Add in logical methods to disable.
"""
cls.all = make_invalid_op("all")
cls.any = make_invalid_op("any")
@property
def shape(self):
"""
Return a tuple of the shape of the underlying data.
"""
# not using "(len(self), )" to return "correct" shape if the values
# consists of a >1 D array (see GH-27775)
# overridden in MultiIndex.shape to avoid materializing the values
return self._values.shape
Index._add_numeric_methods_disabled()
Index._add_logical_methods()
Index._add_comparison_methods()
def ensure_index_from_sequences(sequences, names=None):
"""
Construct an index from sequences of data.
A single sequence returns an Index. Many sequences returns a
MultiIndex.
Parameters
----------
sequences : sequence of sequences
names : sequence of str
Returns
-------
index : Index or MultiIndex
Examples
--------
>>> ensure_index_from_sequences([[1, 2, 3]], names=['name'])
Int64Index([1, 2, 3], dtype='int64', name='name')
>>> ensure_index_from_sequences([['a', 'a'], ['a', 'b']],
names=['L1', 'L2'])
MultiIndex([('a', 'a'),
('a', 'b')],
names=['L1', 'L2'])
See Also
--------
ensure_index
"""
from .multi import MultiIndex
if len(sequences) == 1:
if names is not None:
names = names[0]
return Index(sequences[0], name=names)
else:
return MultiIndex.from_arrays(sequences, names=names)
def ensure_index(index_like, copy=False):
"""
Ensure that we have an index from some index-like object.
Parameters
----------
index : sequence
An Index or other sequence
copy : bool
Returns
-------
index : Index or MultiIndex
Examples
--------
>>> ensure_index(['a', 'b'])
Index(['a', 'b'], dtype='object')
>>> ensure_index([('a', 'a'), ('b', 'c')])
Index([('a', 'a'), ('b', 'c')], dtype='object')
>>> ensure_index([['a', 'a'], ['b', 'c']])
MultiIndex([('a', 'b'),
('a', 'c')],
dtype='object')
)
See Also
--------
ensure_index_from_sequences
"""
if isinstance(index_like, Index):
if copy:
index_like = index_like.copy()
return index_like
if hasattr(index_like, "name"):
return Index(index_like, name=index_like.name, copy=copy)
if is_iterator(index_like):
index_like = list(index_like)
# must check for exactly list here because of strict type
# check in clean_index_list
if isinstance(index_like, list):
if type(index_like) != list:
index_like = list(index_like)
converted, all_arrays = lib.clean_index_list(index_like)
if len(converted) > 0 and all_arrays:
from .multi import MultiIndex
return MultiIndex.from_arrays(converted)
else:
index_like = converted
else:
# clean_index_list does the equivalent of copying
# so only need to do this if not list instance
if copy:
from copy import copy
index_like = copy(index_like)
return Index(index_like)
def _ensure_has_len(seq):
"""
If seq is an iterator, put its values into a list.
"""
try:
len(seq)
except TypeError:
return list(seq)
else:
return seq
def _trim_front(strings):
"""
Trims zeros and decimal points.
"""
trimmed = strings
while len(strings) > 0 and all(x[0] == " " for x in trimmed):
trimmed = [x[1:] for x in trimmed]
return trimmed
def _validate_join_method(method):
if method not in ["left", "right", "inner", "outer"]:
raise ValueError(f"do not recognize join method {method}")
def default_index(n):
from pandas.core.index import RangeIndex
return RangeIndex(0, n, name=None)
from datetime import datetime
import operator
from textwrap import dedent
from typing import FrozenSet, Union
import warnings
import numpy as np
from pandas._libs import algos as libalgos, index as libindex, lib
import pandas._libs.join as libjoin
from pandas._libs.lib import is_datetime_array
from pandas._libs.tslibs import OutOfBoundsDatetime, Timestamp
from pandas._libs.tslibs.period import IncompatibleFrequency
from pandas._libs.tslibs.timezones import tz_compare
from pandas.compat import set_function_name
from pandas.compat.numpy import function as nv
from pandas.util._decorators import Appender, Substitution, cache_readonly
from pandas.core.dtypes import concat as _concat
from pandas.core.dtypes.cast import maybe_cast_to_integer_array
from pandas.core.dtypes.common import (
ensure_categorical,
ensure_int64,
ensure_object,
ensure_platform_int,
is_bool,
is_bool_dtype,
is_categorical,
is_categorical_dtype,
is_datetime64_any_dtype,
is_datetime64tz_dtype,
is_dtype_equal,
is_extension_array_dtype,
is_float,
is_float_dtype,
is_hashable,
is_integer,
is_integer_dtype,
is_interval_dtype,
is_iterator,
is_list_like,
is_object_dtype,
is_period_dtype,
is_scalar,
is_signed_integer_dtype,
is_timedelta64_dtype,
is_unsigned_integer_dtype,
)
from pandas.core.dtypes.concat import concat_compat
from pandas.core.dtypes.generic import (
ABCCategorical,
ABCDataFrame,
ABCDatetimeArray,
ABCDatetimeIndex,
ABCIndexClass,
ABCIntervalIndex,
ABCMultiIndex,
ABCPandasArray,
ABCPeriodIndex,
ABCSeries,
ABCTimedeltaIndex,
)
from pandas.core.dtypes.missing import array_equivalent, isna
from pandas.core import ops
from pandas.core.accessor import CachedAccessor
import pandas.core.algorithms as algos
from pandas.core.arrays import ExtensionArray
from pandas.core.base import IndexOpsMixin, PandasObject
import pandas.core.common as com
from pandas.core.construction import extract_array
from pandas.core.indexers import maybe_convert_indices
from pandas.core.indexes.frozen import FrozenList
import pandas.core.missing as missing
from pandas.core.ops import get_op_result_name
from pandas.core.ops.invalid import make_invalid_op
from pandas.core.strings import StringMethods
from pandas.io.formats.printing import (
default_pprint,
format_object_attrs,
format_object_summary,
pprint_thing,
)
__all__ = ["Index"]
_unsortable_types = frozenset(("mixed", "mixed-integer"))
_index_doc_kwargs = dict(
klass="Index",
inplace="",
target_klass="Index",
raises_section="",
unique="Index",
duplicated="np.ndarray",
)
_index_shared_docs = dict()
def _make_comparison_op(op, cls):
def cmp_method(self, other):
if isinstance(other, (np.ndarray, Index, ABCSeries, ExtensionArray)):
if other.ndim > 0 and len(self) != len(other):
raise ValueError("Lengths must match to compare")
if is_object_dtype(self) and isinstance(other, ABCCategorical):
left = type(other)(self._values, dtype=other.dtype)
return op(left, other)
elif is_object_dtype(self) and not isinstance(self, ABCMultiIndex):
# don't pass MultiIndex
with np.errstate(all="ignore"):
result = ops.comp_method_OBJECT_ARRAY(op, self.values, other)
else:
with np.errstate(all="ignore"):
result = op(self.values, np.asarray(other))
if is_bool_dtype(result):
return result
return ops.invalid_comparison(self, other, op)
name = f"__{op.__name__}__"
return set_function_name(cmp_method, name, cls)
def _make_arithmetic_op(op, cls):
def index_arithmetic_method(self, other):
if isinstance(other, (ABCSeries, ABCDataFrame, ABCTimedeltaIndex)):
return NotImplemented
from pandas import Series
result = op(Series(self), other)
if isinstance(result, tuple):
return (Index(result[0]), Index(result[1]))
return Index(result)
name = f"__{op.__name__}__"
# TODO: docstring?
return set_function_name(index_arithmetic_method, name, cls)
class InvalidIndexError(Exception):
pass
_o_dtype = np.dtype(object)
_Identity = object
def _new_Index(cls, d):
"""
This is called upon unpickling, rather than the default which doesn't
have arguments and breaks __new__.
"""
# required for backward compat, because PI can't be instantiated with
# ordinals through __new__ GH #13277
if issubclass(cls, ABCPeriodIndex):
from pandas.core.indexes.period import _new_PeriodIndex
return _new_PeriodIndex(cls, **d)
if issubclass(cls, ABCMultiIndex):
if "labels" in d and "codes" not in d:
# GH#23752 "labels" kwarg has been replaced with "codes"
d["codes"] = d.pop("labels")
return cls.__new__(cls, **d)
class Index(IndexOpsMixin, PandasObject):
"""
Immutable ndarray implementing an ordered, sliceable set. The basic object
storing axis labels for all pandas objects.
Parameters
----------
data : array-like (1-dimensional)
dtype : NumPy dtype (default: object)
If dtype is None, we find the dtype that best fits the data.
If an actual dtype is provided, we coerce to that dtype if it's safe.
Otherwise, an error will be raised.
copy : bool
Make a copy of input ndarray.
name : object
Name to be stored in the index.
tupleize_cols : bool (default: True)
When True, attempt to create a MultiIndex if possible.
See Also
--------
RangeIndex : Index implementing a monotonic integer range.
CategoricalIndex : Index of :class:`Categorical` s.
MultiIndex : A multi-level, or hierarchical, Index.
IntervalIndex : An Index of :class:`Interval` s.
DatetimeIndex, TimedeltaIndex, PeriodIndex
Int64Index, UInt64Index, Float64Index
Notes
-----
An Index instance can **only** contain hashable objects
Examples
--------
>>> pd.Index([1, 2, 3])
Int64Index([1, 2, 3], dtype='int64')
>>> pd.Index(list('abc'))
Index(['a', 'b', 'c'], dtype='object')
"""
# tolist is not actually deprecated, just suppressed in the __dir__
_deprecations: FrozenSet[str] = (
PandasObject._deprecations
| IndexOpsMixin._deprecations
| frozenset(["contains", "set_value"])
)
# To hand over control to subclasses
_join_precedence = 1
# Cython methods; see github.com/cython/cython/issues/2647
# for why we need to wrap these instead of making them class attributes
# Moreover, cython will choose the appropriate-dtyped sub-function
# given the dtypes of the passed arguments
def _left_indexer_unique(self, left, right):
return libjoin.left_join_indexer_unique(left, right)
def _left_indexer(self, left, right):
return libjoin.left_join_indexer(left, right)
def _inner_indexer(self, left, right):
return libjoin.inner_join_indexer(left, right)
def _outer_indexer(self, left, right):
return libjoin.outer_join_indexer(left, right)
_typ = "index"
_data: Union[ExtensionArray, np.ndarray]
_id = None
name = None
_comparables = ["name"]
_attributes = ["name"]
_is_numeric_dtype = False
_can_hold_na = True
# would we like our indexing holder to defer to us
_defer_to_indexing = False
# prioritize current class for _shallow_copy_with_infer,
# used to infer integers as datetime-likes
_infer_as_myclass = False
_engine_type = libindex.ObjectEngine
# whether we support partial string indexing. Overridden
# in DatetimeIndex and PeriodIndex
_supports_partial_string_indexing = False
_accessors = {"str"}
str = CachedAccessor("str", StringMethods)
# --------------------------------------------------------------------
# Constructors
def __new__(
cls, data=None, dtype=None, copy=False, name=None, tupleize_cols=True, **kwargs,
) -> "Index":
from .range import RangeIndex
from pandas import PeriodIndex, DatetimeIndex, TimedeltaIndex
from .numeric import Float64Index, Int64Index, UInt64Index
from .interval import IntervalIndex
from .category import CategoricalIndex
if name is None and hasattr(data, "name"):
name = data.name
if isinstance(data, ABCPandasArray):
# ensure users don't accidentally put a PandasArray in an index.
data = data.to_numpy()
# range
if isinstance(data, RangeIndex):
return RangeIndex(start=data, copy=copy, dtype=dtype, name=name)
elif isinstance(data, range):
return RangeIndex.from_range(data, dtype=dtype, name=name)
# categorical
elif is_categorical_dtype(data) or is_categorical_dtype(dtype):
return CategoricalIndex(data, dtype=dtype, copy=copy, name=name, **kwargs)
# interval
elif (
is_interval_dtype(data) or is_interval_dtype(dtype)
) and not is_object_dtype(dtype):
closed = kwargs.get("closed", None)
return IntervalIndex(data, dtype=dtype, name=name, copy=copy, closed=closed)
elif (
is_datetime64_any_dtype(data)
or is_datetime64_any_dtype(dtype)
or "tz" in kwargs
):
if is_dtype_equal(_o_dtype, dtype):
# GH#23524 passing `dtype=object` to DatetimeIndex is invalid,
# will raise in the where `data` is already tz-aware. So
# we leave it out of this step and cast to object-dtype after
# the DatetimeIndex construction.
# Note we can pass copy=False because the .astype below
# will always make a copy
return DatetimeIndex(data, copy=False, name=name, **kwargs).astype(
object
)
else:
return DatetimeIndex(data, copy=copy, name=name, dtype=dtype, **kwargs)
elif is_timedelta64_dtype(data) or is_timedelta64_dtype(dtype):
if is_dtype_equal(_o_dtype, dtype):
# Note we can pass copy=False because the .astype below
# will always make a copy
return TimedeltaIndex(data, copy=False, name=name, **kwargs).astype(
object
)
else:
return TimedeltaIndex(data, copy=copy, name=name, dtype=dtype, **kwargs)
elif is_period_dtype(data) and not is_object_dtype(dtype):
return PeriodIndex(data, copy=copy, name=name, **kwargs)
# extension dtype
elif is_extension_array_dtype(data) or is_extension_array_dtype(dtype):
data = np.asarray(data)
if not (dtype is None or is_object_dtype(dtype)):
# coerce to the provided dtype
ea_cls = dtype.construct_array_type()
data = ea_cls._from_sequence(data, dtype=dtype, copy=False)
# coerce to the object dtype
data = data.astype(object)
return Index(data, dtype=object, copy=copy, name=name, **kwargs)
# index-like
elif isinstance(data, (np.ndarray, Index, ABCSeries)):
if dtype is not None:
# we need to avoid having numpy coerce
# things that look like ints/floats to ints unless
# they are actually ints, e.g. '0' and 0.0
# should not be coerced
# GH 11836
if is_integer_dtype(dtype):
inferred = lib.infer_dtype(data, skipna=False)
if inferred == "integer":
data = maybe_cast_to_integer_array(data, dtype, copy=copy)
elif inferred in ["floating", "mixed-integer-float"]:
if isna(data).any():
raise ValueError("cannot convert float NaN to integer")
if inferred == "mixed-integer-float":
data = maybe_cast_to_integer_array(data, dtype)
# If we are actually all equal to integers,
# then coerce to integer.
try:
return cls._try_convert_to_int_index(
data, copy, name, dtype
)
except ValueError:
pass
# Return an actual float index.
return Float64Index(data, copy=copy, name=name)
elif inferred == "string":
pass
else:
data = data.astype(dtype)
elif is_float_dtype(dtype):
inferred = lib.infer_dtype(data, skipna=False)
if inferred == "string":
pass
else:
data = data.astype(dtype)
else:
data = np.array(data, dtype=dtype, copy=copy)
# maybe coerce to a sub-class
if is_signed_integer_dtype(data.dtype):
return Int64Index(data, copy=copy, dtype=dtype, name=name)
elif is_unsigned_integer_dtype(data.dtype):
return UInt64Index(data, copy=copy, dtype=dtype, name=name)
elif is_float_dtype(data.dtype):
return Float64Index(data, copy=copy, dtype=dtype, name=name)
elif issubclass(data.dtype.type, np.bool) or is_bool_dtype(data):
subarr = data.astype("object")
else:
subarr = com.asarray_tuplesafe(data, dtype=object)
# asarray_tuplesafe does not always copy underlying data,
# so need to make sure that this happens
if copy:
subarr = subarr.copy()
if dtype is None:
inferred = lib.infer_dtype(subarr, skipna=False)
if inferred == "integer":
try:
return cls._try_convert_to_int_index(subarr, copy, name, dtype)
except ValueError:
pass
return Index(subarr, copy=copy, dtype=object, name=name)
elif inferred in ["floating", "mixed-integer-float", "integer-na"]:
# TODO: Returns IntegerArray for integer-na case in the future
return Float64Index(subarr, copy=copy, name=name)
elif inferred == "interval":
try:
return IntervalIndex(subarr, name=name, copy=copy)
except ValueError:
# GH27172: mixed closed Intervals --> object dtype
pass
elif inferred == "boolean":
# don't support boolean explicitly ATM
pass
elif inferred != "string":
if inferred.startswith("datetime"):
try:
return DatetimeIndex(subarr, copy=copy, name=name, **kwargs)
except (ValueError, OutOfBoundsDatetime):
# GH 27011
# If we have mixed timezones, just send it
# down the base constructor
pass
elif inferred.startswith("timedelta"):
return TimedeltaIndex(subarr, copy=copy, name=name, **kwargs)
elif inferred == "period":
try:
return PeriodIndex(subarr, name=name, **kwargs)
except IncompatibleFrequency:
pass
if kwargs:
raise TypeError(f"Unexpected keyword arguments {repr(set(kwargs))}")
return cls._simple_new(subarr, name, **kwargs)
elif hasattr(data, "__array__"):
return Index(np.asarray(data), dtype=dtype, copy=copy, name=name, **kwargs)
elif data is None or is_scalar(data):
raise cls._scalar_data_error(data)
else:
if tupleize_cols and is_list_like(data):
# GH21470: convert iterable to list before determining if empty
if is_iterator(data):
data = list(data)
if data and all(isinstance(e, tuple) for e in data):
# we must be all tuples, otherwise don't construct
# 10697
from .multi import MultiIndex
return MultiIndex.from_tuples(
data, names=name or kwargs.get("names")
)
# other iterable of some kind
subarr = com.asarray_tuplesafe(data, dtype=object)
return Index(subarr, dtype=dtype, copy=copy, name=name, **kwargs)
"""
NOTE for new Index creation:
- _simple_new: It returns new Index with the same type as the caller.
All metadata (such as name) must be provided by caller's responsibility.
Using _shallow_copy is recommended because it fills these metadata
otherwise specified.
- _shallow_copy: It returns new Index with the same type (using
_simple_new), but fills caller's metadata otherwise specified. Passed
kwargs will overwrite corresponding metadata.
- _shallow_copy_with_infer: It returns new Index inferring its type
from passed values. It fills caller's metadata otherwise specified as the
same as _shallow_copy.
See each method's docstring.
"""
@property
def asi8(self):
"""
Integer representation of the values.
Returns
-------
ndarray
An ndarray with int64 dtype.
"""
return None
@classmethod
def _simple_new(cls, values, name=None, dtype=None):
"""
We require that we have a dtype compat for the values. If we are passed
a non-dtype compat, then coerce using the constructor.
Must be careful not to recurse.
"""
if isinstance(values, (ABCSeries, ABCIndexClass)):
# Index._data must always be an ndarray.
# This is no-copy for when _values is an ndarray,
# which should be always at this point.
values = np.asarray(values._values)
result = object.__new__(cls)
result._data = values
# _index_data is a (temporary?) fix to ensure that the direct data
# manipulation we do in `_libs/reduction.pyx` continues to work.
# We need access to the actual ndarray, since we're messing with
# data buffers and strides. We don't re-use `_ndarray_values`, since
# we actually set this value too.
result._index_data = values
result.name = name
return result._reset_identity()
@cache_readonly
def _constructor(self):
return type(self)
# --------------------------------------------------------------------
# Index Internals Methods
def _get_attributes_dict(self):
"""
Return an attributes dict for my class.
"""
return {k: getattr(self, k, None) for k in self._attributes}
_index_shared_docs[
"_shallow_copy"
] = """
Create a new Index with the same class as the caller, don't copy the
data, use the same object attributes with passed in attributes taking
precedence.
*this is an internal non-public method*
Parameters
----------
values : the values to create the new Index, optional
kwargs : updates the default attributes for this Index
"""
@Appender(_index_shared_docs["_shallow_copy"])
def _shallow_copy(self, values=None, **kwargs):
if values is None:
values = self.values
attributes = self._get_attributes_dict()
attributes.update(kwargs)
if not len(values) and "dtype" not in kwargs:
attributes["dtype"] = self.dtype
# _simple_new expects an the type of self._data
values = getattr(values, "_values", values)
if isinstance(values, ABCDatetimeArray):
# `self.values` returns `self` for tz-aware, so we need to unwrap
# more specifically
values = values.asi8
return self._simple_new(values, **attributes)
def _shallow_copy_with_infer(self, values, **kwargs):
"""
Create a new Index inferring the class with passed value, don't copy
the data, use the same object attributes with passed in attributes
taking precedence.
*this is an internal non-public method*
Parameters
----------
values : the values to create the new Index, optional
kwargs : updates the default attributes for this Index
"""
attributes = self._get_attributes_dict()
attributes.update(kwargs)
attributes["copy"] = False
if not len(values) and "dtype" not in kwargs:
attributes["dtype"] = self.dtype
if self._infer_as_myclass:
try:
return self._constructor(values, **attributes)
except (TypeError, ValueError):
pass
return Index(values, **attributes)
def _update_inplace(self, result, **kwargs):
# guard when called from IndexOpsMixin
raise TypeError("Index can't be updated inplace")
def is_(self, other) -> bool:
"""
More flexible, faster check like ``is`` but that works through views.
Note: this is *not* the same as ``Index.identical()``, which checks
that metadata is also the same.
Parameters
----------
other : object
other object to compare against.
Returns
-------
True if both have same underlying data, False otherwise : bool
"""
# use something other than None to be clearer
return self._id is getattr(other, "_id", Ellipsis) and self._id is not None
def _reset_identity(self):
"""
Initializes or resets ``_id`` attribute with new object.
"""
self._id = _Identity()
return self
def _cleanup(self):
self._engine.clear_mapping()
@cache_readonly
def _engine(self):
# property, for now, slow to look up
# to avoid a reference cycle, bind `_ndarray_values` to a local variable, so
# `self` is not passed into the lambda.
_ndarray_values = self._ndarray_values
return self._engine_type(lambda: _ndarray_values, len(self))
# --------------------------------------------------------------------
# Array-Like Methods
# ndarray compat
def __len__(self) -> int:
"""
Return the length of the Index.
"""
return len(self._data)
def __array__(self, dtype=None):
"""
The array interface, return my values.
"""
return np.asarray(self._data, dtype=dtype)
def __array_wrap__(self, result, context=None):
"""
Gets called after a ufunc.
"""
result = lib.item_from_zerodim(result)
if is_bool_dtype(result) or lib.is_scalar(result):
return result
attrs = self._get_attributes_dict()
return Index(result, **attrs)
@cache_readonly
def dtype(self):
"""
Return the dtype object of the underlying data.
"""
return self._data.dtype
def ravel(self, order="C"):
"""
Return an ndarray of the flattened values of the underlying data.
Returns
-------
numpy.ndarray
Flattened array.
See Also
--------
numpy.ndarray.ravel
"""
return self._ndarray_values.ravel(order=order)
def view(self, cls=None):
# we need to see if we are subclassing an
# index type here
if cls is not None and not hasattr(cls, "_typ"):
result = self._data.view(cls)
else:
result = self._shallow_copy()
if isinstance(result, Index):
result._id = self._id
return result
_index_shared_docs[
"astype"
] = """
Create an Index with values cast to dtypes. The class of a new Index
is determined by dtype. When conversion is impossible, a ValueError
exception is raised.
Parameters
----------
dtype : numpy dtype or pandas type
Note that any signed integer `dtype` is treated as ``'int64'``,
and any unsigned integer `dtype` is treated as ``'uint64'``,
regardless of the size.
copy : bool, default True
By default, astype always returns a newly allocated object.
If copy is set to False and internal requirements on dtype are
satisfied, the original data is used to create a new Index
or the original Index is returned.
Returns
-------
Index
Index with values cast to specified dtype.
"""
@Appender(_index_shared_docs["astype"])
def astype(self, dtype, copy=True):
if is_dtype_equal(self.dtype, dtype):
return self.copy() if copy else self
elif is_categorical_dtype(dtype):
from .category import CategoricalIndex
return CategoricalIndex(self.values, name=self.name, dtype=dtype, copy=copy)
elif is_extension_array_dtype(dtype):
return Index(np.asarray(self), dtype=dtype, copy=copy)
try:
return Index(
self.values.astype(dtype, copy=copy), name=self.name, dtype=dtype
)
except (TypeError, ValueError):
raise TypeError(f"Cannot cast {type(self).__name__} to dtype {dtype}")
_index_shared_docs[
"take"
] = """
Return a new %(klass)s of the values selected by the indices.
For internal compatibility with numpy arrays.
Parameters
----------
indices : list
Indices to be taken.
axis : int, optional
The axis over which to select values, always 0.
allow_fill : bool, default True
fill_value : bool, default None
If allow_fill=True and fill_value is not None, indices specified by
-1 is regarded as NA. If Index doesn't hold NA, raise ValueError.
Returns
-------
numpy.ndarray
Elements of given indices.
See Also
--------
numpy.ndarray.take
"""
@Appender(_index_shared_docs["take"] % _index_doc_kwargs)
def take(self, indices, axis=0, allow_fill=True, fill_value=None, **kwargs):
if kwargs:
nv.validate_take(tuple(), kwargs)
indices = ensure_platform_int(indices)
if self._can_hold_na:
taken = self._assert_take_fillable(
self.values,
indices,
allow_fill=allow_fill,
fill_value=fill_value,
na_value=self._na_value,
)
else:
if allow_fill and fill_value is not None:
cls_name = type(self).__name__
raise ValueError(
f"Unable to fill values because {cls_name} cannot contain NA"
)
taken = self.values.take(indices)
return self._shallow_copy(taken)
def _assert_take_fillable(
self, values, indices, allow_fill=True, fill_value=None, na_value=np.nan
):
"""
Internal method to handle NA filling of take.
"""
indices = ensure_platform_int(indices)
# only fill if we are passing a non-None fill_value
if allow_fill and fill_value is not None:
if (indices < -1).any():
msg = (
"When allow_fill=True and fill_value is not None, "
"all indices must be >= -1"
)
raise ValueError(msg)
taken = algos.take(
values, indices, allow_fill=allow_fill, fill_value=na_value
)
else:
taken = values.take(indices)
return taken
_index_shared_docs[
"repeat"
] = """
Repeat elements of a %(klass)s.
Returns a new %(klass)s where each element of the current %(klass)s
is repeated consecutively a given number of times.
Parameters
----------
repeats : int or array of ints
The number of repetitions for each element. This should be a
non-negative integer. Repeating 0 times will return an empty
%(klass)s.
axis : None
Must be ``None``. Has no effect but is accepted for compatibility
with numpy.
Returns
-------
repeated_index : %(klass)s
Newly created %(klass)s with repeated elements.
See Also
--------
Series.repeat : Equivalent function for Series.
numpy.repeat : Similar method for :class:`numpy.ndarray`.
Examples
--------
>>> idx = pd.Index(['a', 'b', 'c'])
>>> idx
Index(['a', 'b', 'c'], dtype='object')
>>> idx.repeat(2)
Index(['a', 'a', 'b', 'b', 'c', 'c'], dtype='object')
>>> idx.repeat([1, 2, 3])
Index(['a', 'b', 'b', 'c', 'c', 'c'], dtype='object')
"""
@Appender(_index_shared_docs["repeat"] % _index_doc_kwargs)
def repeat(self, repeats, axis=None):
repeats = ensure_platform_int(repeats)
nv.validate_repeat(tuple(), dict(axis=axis))
return self._shallow_copy(self._values.repeat(repeats))
# --------------------------------------------------------------------
# Copying Methods
_index_shared_docs[
"copy"
] = """
Make a copy of this object. Name and dtype sets those attributes on
the new object.
Parameters
----------
name : str, optional
deep : bool, default False
dtype : numpy dtype or pandas type
Returns
-------
copy : Index
Notes
-----
In most cases, there should be no functional difference from using
``deep``, but if ``deep`` is passed it will attempt to deepcopy.
"""
@Appender(_index_shared_docs["copy"])
def copy(self, name=None, deep=False, dtype=None, **kwargs):
if deep:
new_index = self._shallow_copy(self._data.copy())
else:
new_index = self._shallow_copy()
names = kwargs.get("names")
names = self._validate_names(name=name, names=names, deep=deep)
new_index = new_index.set_names(names)
if dtype:
new_index = new_index.astype(dtype)
return new_index
def __copy__(self, **kwargs):
return self.copy(**kwargs)
def __deepcopy__(self, memo=None):
"""
Parameters
----------
memo, default None
Standard signature. Unused
"""
if memo is None:
memo = {}
return self.copy(deep=True)
# --------------------------------------------------------------------
# Rendering Methods
def __repr__(self):
"""
Return a string representation for this object.
"""
klass_name = type(self).__name__
data = self._format_data()
attrs = self._format_attrs()
space = self._format_space()
attrs_str = [f"{k}={v}" for k, v in attrs]
prepr = f",{space}".join(attrs_str)
# no data provided, just attributes
if data is None:
data = ""
res = f"{klass_name}({data}{prepr})"
return res
def _format_space(self):
# using space here controls if the attributes
# are line separated or not (the default)
# max_seq_items = get_option('display.max_seq_items')
# if len(self) > max_seq_items:
# space = "\n%s" % (' ' * (len(klass) + 1))
return " "
@property
def _formatter_func(self):
"""
Return the formatter function.
"""
return default_pprint
def _format_data(self, name=None):
"""
Return the formatted data as a unicode string.
"""
# do we want to justify (only do so for non-objects)
is_justify = not (
self.inferred_type in ("string", "unicode")
or (
self.inferred_type == "categorical" and is_object_dtype(self.categories)
)
)
return format_object_summary(
self, self._formatter_func, is_justify=is_justify, name=name
)
def _format_attrs(self):
"""
Return a list of tuples of the (attr,formatted_value).
"""
return format_object_attrs(self)
def _mpl_repr(self):
# how to represent ourselves to matplotlib
return self.values
def format(self, name=False, formatter=None, **kwargs):
"""
Render a string representation of the Index.
"""
header = []
if name:
header.append(
pprint_thing(self.name, escape_chars=("\t", "\r", "\n"))
if self.name is not None
else ""
)
if formatter is not None:
return header + list(self.map(formatter))
return self._format_with_header(header, **kwargs)
def _format_with_header(self, header, na_rep="NaN", **kwargs):
values = self.values
from pandas.io.formats.format import format_array
if is_categorical_dtype(values.dtype):
values = np.array(values)
elif is_object_dtype(values.dtype):
values = lib.maybe_convert_objects(values, safe=1)
if is_object_dtype(values.dtype):
result = [pprint_thing(x, escape_chars=("\t", "\r", "\n")) for x in values]
# could have nans
mask = isna(values)
if mask.any():
result = np.array(result)
result[mask] = na_rep
result = result.tolist()
else:
result = _trim_front(format_array(values, None, justify="left"))
return header + result
def to_native_types(self, slicer=None, **kwargs):
"""
Format specified values of `self` and return them.
Parameters
----------
slicer : int, array-like
An indexer into `self` that specifies which values
are used in the formatting process.
kwargs : dict
Options for specifying how the values should be formatted.
These options include the following:
1) na_rep : str
The value that serves as a placeholder for NULL values
2) quoting : bool or None
Whether or not there are quoted values in `self`
3) date_format : str
The format used to represent date-like values.
Returns
-------
numpy.ndarray
Formatted values.
"""
values = self
if slicer is not None:
values = values[slicer]
return values._format_native_types(**kwargs)
def _format_native_types(self, na_rep="", quoting=None, **kwargs):
"""
Actually format specific types of the index.
"""
mask = isna(self)
if not self.is_object() and not quoting:
values = np.asarray(self).astype(str)
else:
values = np.array(self, dtype=object, copy=True)
values[mask] = na_rep
return values
def _summary(self, name=None):
"""
Return a summarized representation.
Parameters
----------
name : str
name to use in the summary representation
Returns
-------
String with a summarized representation of the index
"""
if len(self) > 0:
head = self[0]
if hasattr(head, "format") and not isinstance(head, str):
head = head.format()
tail = self[-1]
if hasattr(tail, "format") and not isinstance(tail, str):
tail = tail.format()
index_summary = f", {head} to {tail}"
else:
index_summary = ""
if name is None:
name = type(self).__name__
return f"{name}: {len(self)} entries{index_summary}"
# --------------------------------------------------------------------
# Conversion Methods
def to_flat_index(self):
"""
Identity method.
.. versionadded:: 0.24.0
This is implemented for compatibility with subclass implementations
when chaining.
Returns
-------
pd.Index
Caller.
See Also
--------
MultiIndex.to_flat_index : Subclass implementation.
"""
return self
def to_series(self, index=None, name=None):
"""
Create a Series with both index and values equal to the index keys.
Useful with map for returning an indexer based on an index.
Parameters
----------
index : Index, optional
Index of resulting Series. If None, defaults to original index.
name : str, optional
Dame of resulting Series. If None, defaults to name of original
index.
Returns
-------
Series
The dtype will be based on the type of the Index values.
"""
from pandas import Series
if index is None:
index = self._shallow_copy()
if name is None:
name = self.name
return Series(self.values.copy(), index=index, name=name)
def to_frame(self, index=True, name=None):
"""
Create a DataFrame with a column containing the Index.
.. versionadded:: 0.24.0
Parameters
----------
index : bool, default True
Set the index of the returned DataFrame as the original Index.
name : object, default None
The passed name should substitute for the index name (if it has
one).
Returns
-------
DataFrame
DataFrame containing the original Index data.
See Also
--------
Index.to_series : Convert an Index to a Series.
Series.to_frame : Convert Series to DataFrame.
Examples
--------
>>> idx = pd.Index(['Ant', 'Bear', 'Cow'], name='animal')
>>> idx.to_frame()
animal
animal
Ant Ant
Bear Bear
Cow Cow
By default, the original Index is reused. To enforce a new Index:
>>> idx.to_frame(index=False)
animal
0 Ant
1 Bear
2 Cow
To override the name of the resulting column, specify `name`:
>>> idx.to_frame(index=False, name='zoo')
zoo
0 Ant
1 Bear
2 Cow
"""
from pandas import DataFrame
if name is None:
name = self.name or 0
result = DataFrame({name: self._values.copy()})
if index:
result.index = self
return result
# --------------------------------------------------------------------
# Name-Centric Methods
def _validate_names(self, name=None, names=None, deep=False):
"""
Handles the quirks of having a singular 'name' parameter for general
Index and plural 'names' parameter for MultiIndex.
"""
from copy import deepcopy
if names is not None and name is not None:
raise TypeError("Can only provide one of `names` and `name`")
elif names is None and name is None:
return deepcopy(self.names) if deep else self.names
elif names is not None:
if not is_list_like(names):
raise TypeError("Must pass list-like as `names`.")
return names
else:
if not is_list_like(name):
return [name]
return name
def _get_names(self):
return FrozenList((self.name,))
def _set_names(self, values, level=None):
"""
Set new names on index. Each name has to be a hashable type.
Parameters
----------
values : str or sequence
name(s) to set
level : int, level name, or sequence of int/level names (default None)
If the index is a MultiIndex (hierarchical), level(s) to set (None
for all levels). Otherwise level must be None
Raises
------
TypeError if each name is not hashable.
"""
if not is_list_like(values):
raise ValueError("Names must be a list-like")
if len(values) != 1:
raise ValueError(f"Length of new names must be 1, got {len(values)}")
# GH 20527
# All items in 'name' need to be hashable:
for name in values:
if not is_hashable(name):
raise TypeError(f"{type(self).__name__}.name must be a hashable type")
self.name = values[0]
names = property(fset=_set_names, fget=_get_names)
def set_names(self, names, level=None, inplace=False):
"""
Set Index or MultiIndex name.
Able to set new names partially and by level.
Parameters
----------
names : label or list of label
Name(s) to set.
level : int, label or list of int or label, optional
If the index is a MultiIndex, level(s) to set (None for all
levels). Otherwise level must be None.
inplace : bool, default False
Modifies the object directly, instead of creating a new Index or
MultiIndex.
Returns
-------
Index
The same type as the caller or None if inplace is True.
See Also
--------
Index.rename : Able to set new names without level.
Examples
--------
>>> idx = pd.Index([1, 2, 3, 4])
>>> idx
Int64Index([1, 2, 3, 4], dtype='int64')
>>> idx.set_names('quarter')
Int64Index([1, 2, 3, 4], dtype='int64', name='quarter')
>>> idx = pd.MultiIndex.from_product([['python', 'cobra'],
... [2018, 2019]])
>>> idx
MultiIndex([('python', 2018),
('python', 2019),
( 'cobra', 2018),
( 'cobra', 2019)],
)
>>> idx.set_names(['kind', 'year'], inplace=True)
>>> idx
MultiIndex([('python', 2018),
('python', 2019),
( 'cobra', 2018),
( 'cobra', 2019)],
names=['kind', 'year'])
>>> idx.set_names('species', level=0)
MultiIndex([('python', 2018),
('python', 2019),
( 'cobra', 2018),
( 'cobra', 2019)],
names=['species', 'year'])
"""
if level is not None and not isinstance(self, ABCMultiIndex):
raise ValueError("Level must be None for non-MultiIndex")
if level is not None and not is_list_like(level) and is_list_like(names):
msg = "Names must be a string when a single level is provided."
raise TypeError(msg)
if not is_list_like(names) and level is None and self.nlevels > 1:
raise TypeError("Must pass list-like as `names`.")
if not is_list_like(names):
names = [names]
if level is not None and not is_list_like(level):
level = [level]
if inplace:
idx = self
else:
idx = self._shallow_copy()
idx._set_names(names, level=level)
if not inplace:
return idx
def rename(self, name, inplace=False):
"""
Alter Index or MultiIndex name.
Able to set new names without level. Defaults to returning new index.
Length of names must match number of levels in MultiIndex.
Parameters
----------
name : label or list of labels
Name(s) to set.
inplace : bool, default False
Modifies the object directly, instead of creating a new Index or
MultiIndex.
Returns
-------
Index
The same type as the caller or None if inplace is True.
See Also
--------
Index.set_names : Able to set new names partially and by level.
Examples
--------
>>> idx = pd.Index(['A', 'C', 'A', 'B'], name='score')
>>> idx.rename('grade')
Index(['A', 'C', 'A', 'B'], dtype='object', name='grade')
>>> idx = pd.MultiIndex.from_product([['python', 'cobra'],
... [2018, 2019]],
... names=['kind', 'year'])
>>> idx
MultiIndex([('python', 2018),
('python', 2019),
( 'cobra', 2018),
( 'cobra', 2019)],
names=['kind', 'year'])
>>> idx.rename(['species', 'year'])
MultiIndex([('python', 2018),
('python', 2019),
( 'cobra', 2018),
( 'cobra', 2019)],
names=['species', 'year'])
>>> idx.rename('species')
Traceback (most recent call last):
TypeError: Must pass list-like as `names`.
"""
return self.set_names([name], inplace=inplace)
# --------------------------------------------------------------------
# Level-Centric Methods
@property
def nlevels(self) -> int:
"""
Number of levels.
"""
return 1
def _sort_levels_monotonic(self):
"""
Compat with MultiIndex.
"""
return self
def _validate_index_level(self, level):
"""
Validate index level.
For single-level Index getting level number is a no-op, but some
verification must be done like in MultiIndex.
"""
if isinstance(level, int):
if level < 0 and level != -1:
raise IndexError(
f"Too many levels: Index has only 1 level,"
f" {level} is not a valid level number"
)
elif level > 0:
raise IndexError(
f"Too many levels: Index has only 1 level, not {level + 1}"
)
elif level != self.name:
raise KeyError(
f"Requested level ({level}) does not match index name ({self.name})"
)
def _get_level_number(self, level):
self._validate_index_level(level)
return 0
def sortlevel(self, level=None, ascending=True, sort_remaining=None):
"""
For internal compatibility with with the Index API.
Sort the Index. This is for compat with MultiIndex
Parameters
----------
ascending : bool, default True
False to sort in descending order
level, sort_remaining are compat parameters
Returns
-------
Index
"""
return self.sort_values(return_indexer=True, ascending=ascending)
def _get_level_values(self, level):
"""
Return an Index of values for requested level.
This is primarily useful to get an individual level of values from a
MultiIndex, but is provided on Index as well for compatibility.
Parameters
----------
level : int or str
It is either the integer position or the name of the level.
Returns
-------
Index
Calling object, as there is only one level in the Index.
See Also
--------
MultiIndex.get_level_values : Get values for a level of a MultiIndex.
Notes
-----
For Index, level should be 0, since there are no multiple levels.
Examples
--------
>>> idx = pd.Index(list('abc'))
>>> idx
Index(['a', 'b', 'c'], dtype='object')
Get level values by supplying `level` as integer:
>>> idx.get_level_values(0)
Index(['a', 'b', 'c'], dtype='object')
"""
self._validate_index_level(level)
return self
get_level_values = _get_level_values
def droplevel(self, level=0):
"""
Return index with requested level(s) removed.
If resulting index has only 1 level left, the result will be
of Index type, not MultiIndex.
.. versionadded:: 0.23.1 (support for non-MultiIndex)
Parameters
----------
level : int, str, or list-like, default 0
If a string is given, must be the name of a level
If list-like, elements must be names or indexes of levels.
Returns
-------
Index or MultiIndex
"""
if not isinstance(level, (tuple, list)):
level = [level]
levnums = sorted(self._get_level_number(lev) for lev in level)[::-1]
if len(level) == 0:
return self
if len(level) >= self.nlevels:
raise ValueError(
f"Cannot remove {len(level)} levels from an index with {self.nlevels} "
"levels: at least one level must be left."
)
# The two checks above guarantee that here self is a MultiIndex
new_levels = list(self.levels)
new_codes = list(self.codes)
new_names = list(self.names)
for i in levnums:
new_levels.pop(i)
new_codes.pop(i)
new_names.pop(i)
if len(new_levels) == 1:
# set nan if needed
mask = new_codes[0] == -1
result = new_levels[0].take(new_codes[0])
if mask.any():
result = result.putmask(mask, np.nan)
result.name = new_names[0]
return result
else:
from .multi import MultiIndex
return MultiIndex(
levels=new_levels,
codes=new_codes,
names=new_names,
verify_integrity=False,
)
_index_shared_docs[
"_get_grouper_for_level"
] = """
Get index grouper corresponding to an index level
Parameters
----------
mapper: Group mapping function or None
Function mapping index values to groups
level : int or None
Index level
Returns
-------
grouper : Index
Index of values to group on.
labels : ndarray of int or None
Array of locations in level_index.
uniques : Index or None
Index of unique values for level.
"""
@Appender(_index_shared_docs["_get_grouper_for_level"])
def _get_grouper_for_level(self, mapper, level=None):
assert level is None or level == 0
if mapper is None:
grouper = self
else:
grouper = self.map(mapper)
return grouper, None, None
# --------------------------------------------------------------------
# Introspection Methods
@property
def is_monotonic(self) -> bool:
"""
Alias for is_monotonic_increasing.
"""
return self.is_monotonic_increasing
@property
def is_monotonic_increasing(self):
"""
Return if the index is monotonic increasing (only equal or
increasing) values.
Examples
--------
>>> Index([1, 2, 3]).is_monotonic_increasing
True
>>> Index([1, 2, 2]).is_monotonic_increasing
True
>>> Index([1, 3, 2]).is_monotonic_increasing
False
"""
return self._engine.is_monotonic_increasing
@property
def is_monotonic_decreasing(self) -> bool:
"""
Return if the index is monotonic decreasing (only equal or
decreasing) values.
Examples
--------
>>> Index([3, 2, 1]).is_monotonic_decreasing
True
>>> Index([3, 2, 2]).is_monotonic_decreasing
True
>>> Index([3, 1, 2]).is_monotonic_decreasing
False
"""
return self._engine.is_monotonic_decreasing
@property
def _is_strictly_monotonic_increasing(self) -> bool:
"""
Return if the index is strictly monotonic increasing
(only increasing) values.
Examples
--------
>>> Index([1, 2, 3])._is_strictly_monotonic_increasing
True
>>> Index([1, 2, 2])._is_strictly_monotonic_increasing
False
>>> Index([1, 3, 2])._is_strictly_monotonic_increasing
False
"""
return self.is_unique and self.is_monotonic_increasing
@property
def _is_strictly_monotonic_decreasing(self) -> bool:
"""
Return if the index is strictly monotonic decreasing
(only decreasing) values.
Examples
--------
>>> Index([3, 2, 1])._is_strictly_monotonic_decreasing
True
>>> Index([3, 2, 2])._is_strictly_monotonic_decreasing
False
>>> Index([3, 1, 2])._is_strictly_monotonic_decreasing
False
"""
return self.is_unique and self.is_monotonic_decreasing
@cache_readonly
def is_unique(self) -> bool:
"""
Return if the index has unique values.
"""
return self._engine.is_unique
@property
def has_duplicates(self) -> bool:
return not self.is_unique
def is_boolean(self) -> bool:
return self.inferred_type in ["boolean"]
def is_integer(self) -> bool:
return self.inferred_type in ["integer"]
def is_floating(self) -> bool:
return self.inferred_type in ["floating", "mixed-integer-float", "integer-na"]
def is_numeric(self) -> bool:
return self.inferred_type in ["integer", "floating"]
def is_object(self) -> bool:
return is_object_dtype(self.dtype)
def is_categorical(self) -> bool:
"""
Check if the Index holds categorical data.
Returns
-------
boolean
True if the Index is categorical.
See Also
--------
CategoricalIndex : Index for categorical data.
Examples
--------
>>> idx = pd.Index(["Watermelon", "Orange", "Apple",
... "Watermelon"]).astype("category")
>>> idx.is_categorical()
True
>>> idx = pd.Index([1, 3, 5, 7])
>>> idx.is_categorical()
False
>>> s = pd.Series(["Peter", "Victor", "Elisabeth", "Mar"])
>>> s
0 Peter
1 Victor
2 Elisabeth
3 Mar
dtype: object
>>> s.index.is_categorical()
False
"""
return self.inferred_type in ["categorical"]
def is_interval(self) -> bool:
return self.inferred_type in ["interval"]
def is_mixed(self) -> bool:
return self.inferred_type in ["mixed"]
def holds_integer(self):
"""
Whether the type is an integer type.
"""
return self.inferred_type in ["integer", "mixed-integer"]
@cache_readonly
def inferred_type(self):
"""
Return a string of the type inferred from the values.
"""
return lib.infer_dtype(self, skipna=False)
@cache_readonly
def is_all_dates(self) -> bool:
return is_datetime_array(ensure_object(self.values))
# --------------------------------------------------------------------
# Pickle Methods
def __reduce__(self):
d = dict(data=self._data)
d.update(self._get_attributes_dict())
return _new_Index, (type(self), d), None
def __setstate__(self, state):
"""
Necessary for making this object picklable.
"""
if isinstance(state, dict):
self._data = state.pop("data")
for k, v in state.items():
setattr(self, k, v)
elif isinstance(state, tuple):
if len(state) == 2:
nd_state, own_state = state
data = np.empty(nd_state[1], dtype=nd_state[2])
np.ndarray.__setstate__(data, nd_state)
self.name = own_state[0]
else: # pragma: no cover
data = np.empty(state)
np.ndarray.__setstate__(data, state)
self._data = data
self._reset_identity()
else:
raise Exception("invalid pickle state")
_unpickle_compat = __setstate__
# --------------------------------------------------------------------
# Null Handling Methods
_na_value = np.nan
"""The expected NA value to use with this index."""
@cache_readonly
def _isnan(self):
"""
Return if each value is NaN.
"""
if self._can_hold_na:
return isna(self)
else:
# shouldn't reach to this condition by checking hasnans beforehand
values = np.empty(len(self), dtype=np.bool_)
values.fill(False)
return values
@cache_readonly
def _nan_idxs(self):
if self._can_hold_na:
return self._isnan.nonzero()[0]
else:
return np.array([], dtype=np.int64)
@cache_readonly
def hasnans(self):
"""
Return if I have any nans; enables various perf speedups.
"""
if self._can_hold_na:
return bool(self._isnan.any())
else:
return False
def isna(self):
"""
Detect missing values.
Return a boolean same-sized object indicating if the values are NA.
NA values, such as ``None``, :attr:`numpy.NaN` or :attr:`pd.NaT`, get
mapped to ``True`` values.
Everything else get mapped to ``False`` values. Characters such as
empty strings `''` or :attr:`numpy.inf` are not considered NA values
(unless you set ``pandas.options.mode.use_inf_as_na = True``).
Returns
-------
numpy.ndarray
A boolean array of whether my values are NA.
See Also
--------
Index.notna : Boolean inverse of isna.
Index.dropna : Omit entries with missing values.
isna : Top-level isna.
Series.isna : Detect missing values in Series object.
Examples
--------
Show which entries in a pandas.Index are NA. The result is an
array.
>>> idx = pd.Index([5.2, 6.0, np.NaN])
>>> idx
Float64Index([5.2, 6.0, nan], dtype='float64')
>>> idx.isna()
array([False, False, True], dtype=bool)
Empty strings are not considered NA values. None is considered an NA
value.
>>> idx = pd.Index(['black', '', 'red', None])
>>> idx
Index(['black', '', 'red', None], dtype='object')
>>> idx.isna()
array([False, False, False, True], dtype=bool)
For datetimes, `NaT` (Not a Time) is considered as an NA value.
>>> idx = pd.DatetimeIndex([pd.Timestamp('1940-04-25'),
... pd.Timestamp(''), None, pd.NaT])
>>> idx
DatetimeIndex(['1940-04-25', 'NaT', 'NaT', 'NaT'],
dtype='datetime64[ns]', freq=None)
>>> idx.isna()
array([False, True, True, True], dtype=bool)
"""
return self._isnan
isnull = isna
def notna(self):
"""
Detect existing (non-missing) values.
Return a boolean same-sized object indicating if the values are not NA.
Non-missing values get mapped to ``True``. Characters such as empty
strings ``''`` or :attr:`numpy.inf` are not considered NA values
(unless you set ``pandas.options.mode.use_inf_as_na = True``).
NA values, such as None or :attr:`numpy.NaN`, get mapped to ``False``
values.
Returns
-------
numpy.ndarray
Boolean array to indicate which entries are not NA.
See Also
--------
Index.notnull : Alias of notna.
Index.isna: Inverse of notna.
notna : Top-level notna.
Examples
--------
Show which entries in an Index are not NA. The result is an
array.
>>> idx = pd.Index([5.2, 6.0, np.NaN])
>>> idx
Float64Index([5.2, 6.0, nan], dtype='float64')
>>> idx.notna()
array([ True, True, False])
Empty strings are not considered NA values. None is considered a NA
value.
>>> idx = pd.Index(['black', '', 'red', None])
>>> idx
Index(['black', '', 'red', None], dtype='object')
>>> idx.notna()
array([ True, True, True, False])
"""
return ~self.isna()
notnull = notna
_index_shared_docs[
"fillna"
] = """
Fill NA/NaN values with the specified value.
Parameters
----------
value : scalar
Scalar value to use to fill holes (e.g. 0).
This value cannot be a list-likes.
downcast : dict, default is None
a dict of item->dtype of what to downcast if possible,
or the string 'infer' which will try to downcast to an appropriate
equal type (e.g. float64 to int64 if possible).
Returns
-------
filled : Index
"""
@Appender(_index_shared_docs["fillna"])
def fillna(self, value=None, downcast=None):
self._assert_can_do_op(value)
if self.hasnans:
result = self.putmask(self._isnan, value)
if downcast is None:
# no need to care metadata other than name
# because it can't have freq if
return Index(result, name=self.name)
return self._shallow_copy()
_index_shared_docs[
"dropna"
] = """
Return Index without NA/NaN values.
Parameters
----------
how : {'any', 'all'}, default 'any'
If the Index is a MultiIndex, drop the value when any or all levels
are NaN.
Returns
-------
valid : Index
"""
@Appender(_index_shared_docs["dropna"])
def dropna(self, how="any"):
if how not in ("any", "all"):
raise ValueError(f"invalid how option: {how}")
if self.hasnans:
return self._shallow_copy(self.values[~self._isnan])
return self._shallow_copy()
# --------------------------------------------------------------------
# Uniqueness Methods
_index_shared_docs[
"index_unique"
] = """
Return unique values in the index. Uniques are returned in order
of appearance, this does NOT sort.
Parameters
----------
level : int or str, optional, default None
Only return values from specified level (for MultiIndex).
.. versionadded:: 0.23.0
Returns
-------
Index without duplicates
See Also
--------
unique
Series.unique
"""
@Appender(_index_shared_docs["index_unique"] % _index_doc_kwargs)
def unique(self, level=None):
if level is not None:
self._validate_index_level(level)
result = super().unique()
return self._shallow_copy(result)
def drop_duplicates(self, keep="first"):
"""
Return Index with duplicate values removed.
Parameters
----------
keep : {'first', 'last', ``False``}, default 'first'
- 'first' : Drop duplicates except for the first occurrence.
- 'last' : Drop duplicates except for the last occurrence.
- ``False`` : Drop all duplicates.
Returns
-------
deduplicated : Index
See Also
--------
Series.drop_duplicates : Equivalent method on Series.
DataFrame.drop_duplicates : Equivalent method on DataFrame.
Index.duplicated : Related method on Index, indicating duplicate
Index values.
Examples
--------
Generate an pandas.Index with duplicate values.
>>> idx = pd.Index(['lama', 'cow', 'lama', 'beetle', 'lama', 'hippo'])
The `keep` parameter controls which duplicate values are removed.
The value 'first' keeps the first occurrence for each
set of duplicated entries. The default value of keep is 'first'.
>>> idx.drop_duplicates(keep='first')
Index(['lama', 'cow', 'beetle', 'hippo'], dtype='object')
The value 'last' keeps the last occurrence for each set of duplicated
entries.
>>> idx.drop_duplicates(keep='last')
Index(['cow', 'beetle', 'lama', 'hippo'], dtype='object')
The value ``False`` discards all sets of duplicated entries.
>>> idx.drop_duplicates(keep=False)
Index(['cow', 'beetle', 'hippo'], dtype='object')
"""
return super().drop_duplicates(keep=keep)
def duplicated(self, keep="first"):
"""
Indicate duplicate index values.
Duplicated values are indicated as ``True`` values in the resulting
array. Either all duplicates, all except the first, or all except the
last occurrence of duplicates can be indicated.
Parameters
----------
keep : {'first', 'last', False}, default 'first'
The value or values in a set of duplicates to mark as missing.
- 'first' : Mark duplicates as ``True`` except for the first
occurrence.
- 'last' : Mark duplicates as ``True`` except for the last
occurrence.
- ``False`` : Mark all duplicates as ``True``.
Returns
-------
numpy.ndarray
See Also
--------
Series.duplicated : Equivalent method on pandas.Series.
DataFrame.duplicated : Equivalent method on pandas.DataFrame.
Index.drop_duplicates : Remove duplicate values from Index.
Examples
--------
By default, for each set of duplicated values, the first occurrence is
set to False and all others to True:
>>> idx = pd.Index(['lama', 'cow', 'lama', 'beetle', 'lama'])
>>> idx.duplicated()
array([False, False, True, False, True])
which is equivalent to
>>> idx.duplicated(keep='first')
array([False, False, True, False, True])
By using 'last', the last occurrence of each set of duplicated values
is set on False and all others on True:
>>> idx.duplicated(keep='last')
array([ True, False, True, False, False])
By setting keep on ``False``, all duplicates are True:
>>> idx.duplicated(keep=False)
array([ True, False, True, False, True])
"""
return super().duplicated(keep=keep)
def _get_unique_index(self, dropna=False):
"""
Returns an index containing unique values.
Parameters
----------
dropna : bool
If True, NaN values are dropped.
Returns
-------
uniques : index
"""
if self.is_unique and not dropna:
return self
values = self.values
if not self.is_unique:
values = self.unique()
if dropna:
try:
if self.hasnans:
values = values[~isna(values)]
except NotImplementedError:
pass
return self._shallow_copy(values)
# --------------------------------------------------------------------
# Arithmetic & Logical Methods
def __add__(self, other):
if isinstance(other, (ABCSeries, ABCDataFrame)):
return NotImplemented
from pandas import Series
return Index(Series(self) + other)
def __radd__(self, other):
from pandas import Series
return Index(other + Series(self))
def __iadd__(self, other):
# alias for __add__
return self + other
def __sub__(self, other):
return Index(np.array(self) - other)
def __rsub__(self, other):
# wrap Series to ensure we pin name correctly
from pandas import Series
return Index(other - Series(self))
def __and__(self, other):
return self.intersection(other)
def __or__(self, other):
return self.union(other)
def __xor__(self, other):
return self.symmetric_difference(other)
def __nonzero__(self):
raise ValueError(
f"The truth value of a {type(self).__name__} is ambiguous. "
"Use a.empty, a.bool(), a.item(), a.any() or a.all()."
)
__bool__ = __nonzero__
# --------------------------------------------------------------------
# Set Operation Methods
def _get_reconciled_name_object(self, other):
"""
If the result of a set operation will be self,
return self, unless the name changes, in which
case make a shallow copy of self.
"""
name = get_op_result_name(self, other)
if self.name != name:
return self._shallow_copy(name=name)
return self
def _union_incompatible_dtypes(self, other, sort):
"""
Casts this and other index to object dtype to allow the formation
of a union between incompatible types.
Parameters
----------
other : Index or array-like
sort : False or None, default False
Whether to sort the resulting index.
* False : do not sort the result.
* None : sort the result, except when `self` and `other` are equal
or when the values cannot be compared.
Returns
-------
Index
"""
this = self.astype(object, copy=False)
# cast to Index for when `other` is list-like
other = Index(other).astype(object, copy=False)
return Index.union(this, other, sort=sort).astype(object, copy=False)
def _is_compatible_with_other(self, other):
"""
Check whether this and the other dtype are compatible with each other.
Meaning a union can be formed between them without needing to be cast
to dtype object.
Parameters
----------
other : Index or array-like
Returns
-------
bool
"""
return type(self) is type(other) and is_dtype_equal(self.dtype, other.dtype)
def _validate_sort_keyword(self, sort):
if sort not in [None, False]:
raise ValueError(
"The 'sort' keyword only takes the values of "
f"None or False; {sort} was passed."
)
def union(self, other, sort=None):
"""
Form the union of two Index objects.
If the Index objects are incompatible, both Index objects will be
cast to dtype('object') first.
.. versionchanged:: 0.25.0
Parameters
----------
other : Index or array-like
sort : bool or None, default None
Whether to sort the resulting Index.
* None : Sort the result, except when
1. `self` and `other` are equal.
2. `self` or `other` has length 0.
3. Some values in `self` or `other` cannot be compared.
A RuntimeWarning is issued in this case.
* False : do not sort the result.
.. versionadded:: 0.24.0
.. versionchanged:: 0.24.1
Changed the default value from ``True`` to ``None``
(without change in behaviour).
Returns
-------
union : Index
Examples
--------
Union matching dtypes
>>> idx1 = pd.Index([1, 2, 3, 4])
>>> idx2 = pd.Index([3, 4, 5, 6])
>>> idx1.union(idx2)
Int64Index([1, 2, 3, 4, 5, 6], dtype='int64')
Union mismatched dtypes
>>> idx1 = pd.Index(['a', 'b', 'c', 'd'])
>>> idx2 = pd.Index([1, 2, 3, 4])
>>> idx1.union(idx2)
Index(['a', 'b', 'c', 'd', 1, 2, 3, 4], dtype='object')
"""
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
if not self._is_compatible_with_other(other):
return self._union_incompatible_dtypes(other, sort=sort)
return self._union(other, sort=sort)
def _union(self, other, sort):
"""
Specific union logic should go here. In subclasses, union behavior
should be overwritten here rather than in `self.union`.
Parameters
----------
other : Index or array-like
sort : False or None, default False
Whether to sort the resulting index.
* False : do not sort the result.
* None : sort the result, except when `self` and `other` are equal
or when the values cannot be compared.
Returns
-------
Index
"""
if not len(other) or self.equals(other):
return self._get_reconciled_name_object(other)
if not len(self):
return other._get_reconciled_name_object(self)
# TODO(EA): setops-refactor, clean all this up
if is_period_dtype(self) or is_datetime64tz_dtype(self):
lvals = self._ndarray_values
else:
lvals = self._values
if is_period_dtype(other) or is_datetime64tz_dtype(other):
rvals = other._ndarray_values
else:
rvals = other._values
if sort is None and self.is_monotonic and other.is_monotonic:
try:
result = self._outer_indexer(lvals, rvals)[0]
except TypeError:
# incomparable objects
result = list(lvals)
# worth making this faster? a very unusual case
value_set = set(lvals)
result.extend([x for x in rvals if x not in value_set])
else:
# find indexes of things in "other" that are not in "self"
if self.is_unique:
indexer = self.get_indexer(other)
indexer = (indexer == -1).nonzero()[0]
else:
indexer = algos.unique1d(self.get_indexer_non_unique(other)[1])
if len(indexer) > 0:
other_diff = algos.take_nd(rvals, indexer, allow_fill=False)
result = concat_compat((lvals, other_diff))
else:
result = lvals
if sort is None:
try:
result = algos.safe_sort(result)
except TypeError as err:
warnings.warn(
f"{err}, sort order is undefined for incomparable objects",
RuntimeWarning,
stacklevel=3,
)
# for subclasses
return self._wrap_setop_result(other, result)
def _wrap_setop_result(self, other, result):
return self._constructor(result, name=get_op_result_name(self, other))
_index_shared_docs[
"intersection"
] = """
Form the intersection of two Index objects.
This returns a new Index with elements common to the index and `other`.
Parameters
----------
other : Index or array-like
sort : False or None, default False
Whether to sort the resulting index.
* False : do not sort the result.
* None : sort the result, except when `self` and `other` are equal
or when the values cannot be compared.
.. versionadded:: 0.24.0
.. versionchanged:: 0.24.1
Changed the default from ``True`` to ``False``, to match
the behaviour of 0.23.4 and earlier.
Returns
-------
intersection : Index
Examples
--------
>>> idx1 = pd.Index([1, 2, 3, 4])
>>> idx2 = pd.Index([3, 4, 5, 6])
>>> idx1.intersection(idx2)
Int64Index([3, 4], dtype='int64')
"""
# TODO: standardize return type of non-union setops type(self vs other)
@Appender(_index_shared_docs["intersection"])
def intersection(self, other, sort=False):
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
other = ensure_index(other)
if self.equals(other):
return self._get_reconciled_name_object(other)
if not is_dtype_equal(self.dtype, other.dtype):
this = self.astype("O")
other = other.astype("O")
return this.intersection(other, sort=sort)
# TODO(EA): setops-refactor, clean all this up
if is_period_dtype(self):
lvals = self._ndarray_values
else:
lvals = self._values
if is_period_dtype(other):
rvals = other._ndarray_values
else:
rvals = other._values
if self.is_monotonic and other.is_monotonic:
try:
result = self._inner_indexer(lvals, rvals)[0]
return self._wrap_setop_result(other, result)
except TypeError:
pass
try:
indexer = Index(rvals).get_indexer(lvals)
indexer = indexer.take((indexer != -1).nonzero()[0])
except (InvalidIndexError, IncompatibleFrequency):
# InvalidIndexError raised by get_indexer if non-unique
# IncompatibleFrequency raised by PeriodIndex.get_indexer
indexer = algos.unique1d(Index(rvals).get_indexer_non_unique(lvals)[0])
indexer = indexer[indexer != -1]
taken = other.take(indexer)
if sort is None:
taken = algos.safe_sort(taken.values)
if self.name != other.name:
name = None
else:
name = self.name
return self._shallow_copy(taken, name=name)
if self.name != other.name:
taken.name = None
return taken
def difference(self, other, sort=None):
"""
Return a new Index with elements from the index that are not in
`other`.
This is the set difference of two Index objects.
Parameters
----------
other : Index or array-like
sort : False or None, default None
Whether to sort the resulting index. By default, the
values are attempted to be sorted, but any TypeError from
incomparable elements is caught by pandas.
* None : Attempt to sort the result, but catch any TypeErrors
from comparing incomparable elements.
* False : Do not sort the result.
.. versionadded:: 0.24.0
.. versionchanged:: 0.24.1
Changed the default value from ``True`` to ``None``
(without change in behaviour).
Returns
-------
difference : Index
Examples
--------
>>> idx1 = pd.Index([2, 1, 3, 4])
>>> idx2 = pd.Index([3, 4, 5, 6])
>>> idx1.difference(idx2)
Int64Index([1, 2], dtype='int64')
>>> idx1.difference(idx2, sort=False)
Int64Index([2, 1], dtype='int64')
"""
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
if self.equals(other):
# pass an empty np.ndarray with the appropriate dtype
return self._shallow_copy(self._data[:0])
other, result_name = self._convert_can_do_setop(other)
this = self._get_unique_index()
indexer = this.get_indexer(other)
indexer = indexer.take((indexer != -1).nonzero()[0])
label_diff = np.setdiff1d(np.arange(this.size), indexer, assume_unique=True)
the_diff = this.values.take(label_diff)
if sort is None:
try:
the_diff = algos.safe_sort(the_diff)
except TypeError:
pass
return this._shallow_copy(the_diff, name=result_name)
def symmetric_difference(self, other, result_name=None, sort=None):
"""
Compute the symmetric difference of two Index objects.
Parameters
----------
other : Index or array-like
result_name : str
sort : False or None, default None
Whether to sort the resulting index. By default, the
values are attempted to be sorted, but any TypeError from
incomparable elements is caught by pandas.
* None : Attempt to sort the result, but catch any TypeErrors
from comparing incomparable elements.
* False : Do not sort the result.
.. versionadded:: 0.24.0
.. versionchanged:: 0.24.1
Changed the default value from ``True`` to ``None``
(without change in behaviour).
Returns
-------
symmetric_difference : Index
Notes
-----
``symmetric_difference`` contains elements that appear in either
``idx1`` or ``idx2`` but not both. Equivalent to the Index created by
``idx1.difference(idx2) | idx2.difference(idx1)`` with duplicates
dropped.
Examples
--------
>>> idx1 = pd.Index([1, 2, 3, 4])
>>> idx2 = pd.Index([2, 3, 4, 5])
>>> idx1.symmetric_difference(idx2)
Int64Index([1, 5], dtype='int64')
You can also use the ``^`` operator:
>>> idx1 ^ idx2
Int64Index([1, 5], dtype='int64')
"""
self._validate_sort_keyword(sort)
self._assert_can_do_setop(other)
other, result_name_update = self._convert_can_do_setop(other)
if result_name is None:
result_name = result_name_update
this = self._get_unique_index()
other = other._get_unique_index()
indexer = this.get_indexer(other)
# {this} minus {other}
common_indexer = indexer.take((indexer != -1).nonzero()[0])
left_indexer = np.setdiff1d(
np.arange(this.size), common_indexer, assume_unique=True
)
left_diff = this.values.take(left_indexer)
# {other} minus {this}
right_indexer = (indexer == -1).nonzero()[0]
right_diff = other.values.take(right_indexer)
the_diff = concat_compat([left_diff, right_diff])
if sort is None:
try:
the_diff = algos.safe_sort(the_diff)
except TypeError:
pass
attribs = self._get_attributes_dict()
attribs["name"] = result_name
if "freq" in attribs:
attribs["freq"] = None
return self._shallow_copy_with_infer(the_diff, **attribs)
def _assert_can_do_setop(self, other):
if not is_list_like(other):
raise TypeError("Input must be Index or array-like")
return True
def _convert_can_do_setop(self, other):
if not isinstance(other, Index):
other = Index(other, name=self.name)
result_name = self.name
else:
result_name = get_op_result_name(self, other)
return other, result_name
# --------------------------------------------------------------------
# Indexing Methods
_index_shared_docs[
"get_loc"
] = """
Get integer location, slice or boolean mask for requested label.
Parameters
----------
key : label
method : {None, 'pad'/'ffill', 'backfill'/'bfill', 'nearest'}, optional
* default: exact matches only.
* pad / ffill: find the PREVIOUS index value if no exact match.
* backfill / bfill: use NEXT index value if no exact match
* nearest: use the NEAREST index value if no exact match. Tied
distances are broken by preferring the larger index value.
tolerance : int or float, optional
Maximum distance from index value for inexact matches. The value of
the index at the matching location most satisfy the equation
``abs(index[loc] - key) <= tolerance``.
.. versionadded:: 0.21.0 (list-like tolerance)
Returns
-------
loc : int if unique index, slice if monotonic index, else mask
Examples
--------
>>> unique_index = pd.Index(list('abc'))
>>> unique_index.get_loc('b')
1
>>> monotonic_index = pd.Index(list('abbc'))
>>> monotonic_index.get_loc('b')
slice(1, 3, None)
>>> non_monotonic_index = pd.Index(list('abcb'))
>>> non_monotonic_index.get_loc('b')
array([False, True, False, True], dtype=bool)
"""
@Appender(_index_shared_docs["get_loc"])
def get_loc(self, key, method=None, tolerance=None):
if method is None:
if tolerance is not None:
raise ValueError(
"tolerance argument only valid if using pad, "
"backfill or nearest lookups"
)
try:
return self._engine.get_loc(key)
except KeyError:
return self._engine.get_loc(self._maybe_cast_indexer(key))
indexer = self.get_indexer([key], method=method, tolerance=tolerance)
if indexer.ndim > 1 or indexer.size > 1:
raise TypeError("get_loc requires scalar valued input")
loc = indexer.item()
if loc == -1:
raise KeyError(key)
return loc
_index_shared_docs[
"get_indexer"
] = """
Compute indexer and mask for new index given the current index. The
indexer should be then used as an input to ndarray.take to align the
current data to the new index.
Parameters
----------
target : %(target_klass)s
method : {None, 'pad'/'ffill', 'backfill'/'bfill', 'nearest'}, optional
* default: exact matches only.
* pad / ffill: find the PREVIOUS index value if no exact match.
* backfill / bfill: use NEXT index value if no exact match
* nearest: use the NEAREST index value if no exact match. Tied
distances are broken by preferring the larger index value.
limit : int, optional
Maximum number of consecutive labels in ``target`` to match for
inexact matches.
tolerance : optional
Maximum distance between original and new labels for inexact
matches. The values of the index at the matching locations most
satisfy the equation ``abs(index[indexer] - target) <= tolerance``.
Tolerance may be a scalar value, which applies the same tolerance
to all values, or list-like, which applies variable tolerance per
element. List-like includes list, tuple, array, Series, and must be
the same size as the index and its dtype must exactly match the
index's type.
.. versionadded:: 0.21.0 (list-like tolerance)
Returns
-------
indexer : ndarray of int
Integers from 0 to n - 1 indicating that the index at these
positions matches the corresponding target values. Missing values
in the target are marked by -1.
%(raises_section)s
Examples
--------
>>> index = pd.Index(['c', 'a', 'b'])
>>> index.get_indexer(['a', 'b', 'x'])
array([ 1, 2, -1])
Notice that the return value is an array of locations in ``index``
and ``x`` is marked by -1, as it is not in ``index``.
"""
@Appender(_index_shared_docs["get_indexer"] % _index_doc_kwargs)
def get_indexer(self, target, method=None, limit=None, tolerance=None):
method = missing.clean_reindex_fill_method(method)
target = ensure_index(target)
if tolerance is not None:
tolerance = self._convert_tolerance(tolerance, target)
# Treat boolean labels passed to a numeric index as not found. Without
# this fix False and True would be treated as 0 and 1 respectively.
# (GH #16877)
if target.is_boolean() and self.is_numeric():
return ensure_platform_int(np.repeat(-1, target.size))
pself, ptarget = self._maybe_promote(target)
if pself is not self or ptarget is not target:
return pself.get_indexer(
ptarget, method=method, limit=limit, tolerance=tolerance
)
if not is_dtype_equal(self.dtype, target.dtype):
this = self.astype(object)
target = target.astype(object)
return this.get_indexer(
target, method=method, limit=limit, tolerance=tolerance
)
if not self.is_unique:
raise InvalidIndexError(
"Reindexing only valid with uniquely valued Index objects"
)
if method == "pad" or method == "backfill":
indexer = self._get_fill_indexer(target, method, limit, tolerance)
elif method == "nearest":
indexer = self._get_nearest_indexer(target, limit, tolerance)
else:
if tolerance is not None:
raise ValueError(
"tolerance argument only valid if doing pad, "
"backfill or nearest reindexing"
)
if limit is not None:
raise ValueError(
"limit argument only valid if doing pad, "
"backfill or nearest reindexing"
)
indexer = self._engine.get_indexer(target._ndarray_values)
return ensure_platform_int(indexer)
def _convert_tolerance(self, tolerance, target):
# override this method on subclasses
tolerance = np.asarray(tolerance)
if target.size != tolerance.size and tolerance.size > 1:
raise ValueError("list-like tolerance size must match target index size")
return tolerance
def _get_fill_indexer(self, target, method, limit=None, tolerance=None):
if self.is_monotonic_increasing and target.is_monotonic_increasing:
method = (
self._engine.get_pad_indexer
if method == "pad"
else self._engine.get_backfill_indexer
)
indexer = method(target._ndarray_values, limit)
else:
indexer = self._get_fill_indexer_searchsorted(target, method, limit)
if tolerance is not None:
indexer = self._filter_indexer_tolerance(
target._ndarray_values, indexer, tolerance
)
return indexer
def _get_fill_indexer_searchsorted(self, target, method, limit=None):
"""
Fallback pad/backfill get_indexer that works for monotonic decreasing
indexes and non-monotonic targets.
"""
if limit is not None:
raise ValueError(
f"limit argument for {repr(method)} method only well-defined "
"if index and target are monotonic"
)
side = "left" if method == "pad" else "right"
# find exact matches first (this simplifies the algorithm)
indexer = self.get_indexer(target)
nonexact = indexer == -1
indexer[nonexact] = self._searchsorted_monotonic(target[nonexact], side)
if side == "left":
# searchsorted returns "indices into a sorted array such that,
# if the corresponding elements in v were inserted before the
# indices, the order of a would be preserved".
# Thus, we need to subtract 1 to find values to the left.
indexer[nonexact] -= 1
# This also mapped not found values (values of 0 from
# np.searchsorted) to -1, which conveniently is also our
# sentinel for missing values
else:
# Mark indices to the right of the largest value as not found
indexer[indexer == len(self)] = -1
return indexer
def _get_nearest_indexer(self, target, limit, tolerance):
"""
Get the indexer for the nearest index labels; requires an index with
values that can be subtracted from each other (e.g., not strings or
tuples).
"""
left_indexer = self.get_indexer(target, "pad", limit=limit)
right_indexer = self.get_indexer(target, "backfill", limit=limit)
target = np.asarray(target)
left_distances = abs(self.values[left_indexer] - target)
right_distances = abs(self.values[right_indexer] - target)
op = operator.lt if self.is_monotonic_increasing else operator.le
indexer = np.where(
op(left_distances, right_distances) | (right_indexer == -1),
left_indexer,
right_indexer,
)
if tolerance is not None:
indexer = self._filter_indexer_tolerance(target, indexer, tolerance)
return indexer
def _filter_indexer_tolerance(self, target, indexer, tolerance):
distance = abs(self.values[indexer] - target)
indexer = np.where(distance <= tolerance, indexer, -1)
return indexer
# --------------------------------------------------------------------
# Indexer Conversion Methods
_index_shared_docs[
"_convert_scalar_indexer"
] = """
Convert a scalar indexer.
Parameters
----------
key : label of the slice bound
kind : {'ix', 'loc', 'getitem', 'iloc'} or None
"""
@Appender(_index_shared_docs["_convert_scalar_indexer"])
def _convert_scalar_indexer(self, key, kind=None):
assert kind in ["ix", "loc", "getitem", "iloc", None]
if kind == "iloc":
return self._validate_indexer("positional", key, kind)
if len(self) and not isinstance(self, ABCMultiIndex):
# we can raise here if we are definitive that this
# is positional indexing (eg. .ix on with a float)
# or label indexing if we are using a type able
# to be represented in the index
if kind in ["getitem", "ix"] and is_float(key):
if not self.is_floating():
return self._invalid_indexer("label", key)
elif kind in ["loc"] and is_float(key):
# we want to raise KeyError on string/mixed here
# technically we *could* raise a TypeError
# on anything but mixed though
if self.inferred_type not in [
"floating",
"mixed-integer-float",
"integer-na",
"string",
"unicode",
"mixed",
]:
self._invalid_indexer("label", key)
elif kind in ["loc"] and is_integer(key):
if not self.holds_integer():
self._invalid_indexer("label", key)
return key
_index_shared_docs[
"_convert_slice_indexer"
] = """
Convert a slice indexer.
By definition, these are labels unless 'iloc' is passed in.
Floats are not allowed as the start, step, or stop of the slice.
Parameters
----------
key : label of the slice bound
kind : {'ix', 'loc', 'getitem', 'iloc'} or None
"""
@Appender(_index_shared_docs["_convert_slice_indexer"])
def _convert_slice_indexer(self, key: slice, kind=None):
assert kind in ["ix", "loc", "getitem", "iloc", None]
# validate iloc
if kind == "iloc":
return slice(
self._validate_indexer("slice", key.start, kind),
self._validate_indexer("slice", key.stop, kind),
self._validate_indexer("slice", key.step, kind),
)
# potentially cast the bounds to integers
start, stop, step = key.start, key.stop, key.step
# figure out if this is a positional indexer
def is_int(v):
return v is None or is_integer(v)
is_null_slicer = start is None and stop is None
is_index_slice = is_int(start) and is_int(stop)
is_positional = is_index_slice and not (
self.is_integer() or self.is_categorical()
)
if kind == "getitem":
"""
called from the getitem slicers, validate that we are in fact
integers
"""
if self.is_integer() or is_index_slice:
return slice(
self._validate_indexer("slice", key.start, kind),
self._validate_indexer("slice", key.stop, kind),
self._validate_indexer("slice", key.step, kind),
)
# convert the slice to an indexer here
# if we are mixed and have integers
try:
if is_positional and self.is_mixed():
# Validate start & stop
if start is not None:
self.get_loc(start)
if stop is not None:
self.get_loc(stop)
is_positional = False
except KeyError:
if self.inferred_type in ["mixed-integer-float", "integer-na"]:
raise
if is_null_slicer:
indexer = key
elif is_positional:
indexer = key
else:
indexer = self.slice_indexer(start, stop, step, kind=kind)
return indexer
def _convert_listlike_indexer(self, keyarr, kind=None):
"""
Parameters
----------
keyarr : list-like
Indexer to convert.
Returns
-------
indexer : numpy.ndarray or None
Return an ndarray or None if cannot convert.
keyarr : numpy.ndarray
Return tuple-safe keys.
"""
if isinstance(keyarr, Index):
keyarr = self._convert_index_indexer(keyarr)
else:
keyarr = self._convert_arr_indexer(keyarr)
indexer = self._convert_list_indexer(keyarr, kind=kind)
return indexer, keyarr
_index_shared_docs[
"_convert_arr_indexer"
] = """
Convert an array-like indexer to the appropriate dtype.
Parameters
----------
keyarr : array-like
Indexer to convert.
Returns
-------
converted_keyarr : array-like
"""
@Appender(_index_shared_docs["_convert_arr_indexer"])
def _convert_arr_indexer(self, keyarr):
keyarr = com.asarray_tuplesafe(keyarr)
return keyarr
_index_shared_docs[
"_convert_index_indexer"
] = """
Convert an Index indexer to the appropriate dtype.
Parameters
----------
keyarr : Index (or sub-class)
Indexer to convert.
Returns
-------
converted_keyarr : Index (or sub-class)
"""
@Appender(_index_shared_docs["_convert_index_indexer"])
def _convert_index_indexer(self, keyarr):
return keyarr
_index_shared_docs[
"_convert_list_indexer"
] = """
Convert a list-like indexer to the appropriate dtype.
Parameters
----------
keyarr : Index (or sub-class)
Indexer to convert.
kind : iloc, ix, loc, optional
Returns
-------
positional indexer or None
"""
@Appender(_index_shared_docs["_convert_list_indexer"])
def _convert_list_indexer(self, keyarr, kind=None):
if (
kind in [None, "iloc", "ix"]
and is_integer_dtype(keyarr)
and not self.is_floating()
and not isinstance(keyarr, ABCPeriodIndex)
):
if self.inferred_type == "mixed-integer":
indexer = self.get_indexer(keyarr)
if (indexer >= 0).all():
return indexer
# missing values are flagged as -1 by get_indexer and negative
# indices are already converted to positive indices in the
# above if-statement, so the negative flags are changed to
# values outside the range of indices so as to trigger an
# IndexError in maybe_convert_indices
indexer[indexer < 0] = len(self)
return maybe_convert_indices(indexer, len(self))
elif not self.inferred_type == "integer":
keyarr = np.where(keyarr < 0, len(self) + keyarr, keyarr)
return keyarr
return None
def _invalid_indexer(self, form, key):
"""
Consistent invalid indexer message.
"""
raise TypeError(
f"cannot do {form} indexing on {type(self)} with these "
f"indexers [{key}] of {type(key)}"
)
# --------------------------------------------------------------------
# Reindex Methods
def _can_reindex(self, indexer):
"""
Check if we are allowing reindexing with this particular indexer.
Parameters
----------
indexer : an integer indexer
Raises
------
ValueError if its a duplicate axis
"""
# trying to reindex on an axis with duplicates
if not self.is_unique and len(indexer):
raise ValueError("cannot reindex from a duplicate axis")
def reindex(self, target, method=None, level=None, limit=None, tolerance=None):
"""
Create index with target's values (move/add/delete values
as necessary).
Parameters
----------
target : an iterable
Returns
-------
new_index : pd.Index
Resulting index.
indexer : np.ndarray or None
Indices of output values in original index.
"""
# GH6552: preserve names when reindexing to non-named target
# (i.e. neither Index nor Series).
preserve_names = not hasattr(target, "name")
# GH7774: preserve dtype/tz if target is empty and not an Index.
target = _ensure_has_len(target) # target may be an iterator
if not isinstance(target, Index) and len(target) == 0:
attrs = self._get_attributes_dict()
attrs.pop("freq", None) # don't preserve freq
values = self._data[:0] # appropriately-dtyped empty array
target = self._simple_new(values, dtype=self.dtype, **attrs)
else:
target = ensure_index(target)
if level is not None:
if method is not None:
raise TypeError("Fill method not supported if level passed")
_, indexer, _ = self._join_level(
target, level, how="right", return_indexers=True
)
else:
if self.equals(target):
indexer = None
else:
# check is_overlapping for IntervalIndex compat
if self.is_unique and not getattr(self, "is_overlapping", False):
indexer = self.get_indexer(
target, method=method, limit=limit, tolerance=tolerance
)
else:
if method is not None or limit is not None:
raise ValueError(
"cannot reindex a non-unique index "
"with a method or limit"
)
indexer, missing = self.get_indexer_non_unique(target)
if preserve_names and target.nlevels == 1 and target.name != self.name:
target = target.copy()
target.name = self.name
return target, indexer
def _reindex_non_unique(self, target):
"""
Create a new index with target's values (move/add/delete values as
necessary) use with non-unique Index and a possibly non-unique target.
Parameters
----------
target : an iterable
Returns
-------
new_index : pd.Index
Resulting index.
indexer : np.ndarray or None
Indices of output values in original index.
"""
target = ensure_index(target)
indexer, missing = self.get_indexer_non_unique(target)
check = indexer != -1
new_labels = self.take(indexer[check])
new_indexer = None
if len(missing):
length = np.arange(len(indexer))
missing = ensure_platform_int(missing)
missing_labels = target.take(missing)
missing_indexer = ensure_int64(length[~check])
cur_labels = self.take(indexer[check]).values
cur_indexer = ensure_int64(length[check])
new_labels = np.empty(tuple([len(indexer)]), dtype=object)
new_labels[cur_indexer] = cur_labels
new_labels[missing_indexer] = missing_labels
# a unique indexer
if target.is_unique:
# see GH5553, make sure we use the right indexer
new_indexer = np.arange(len(indexer))
new_indexer[cur_indexer] = np.arange(len(cur_labels))
new_indexer[missing_indexer] = -1
# we have a non_unique selector, need to use the original
# indexer here
else:
# need to retake to have the same size as the indexer
indexer[~check] = -1
# reset the new indexer to account for the new size
new_indexer = np.arange(len(self.take(indexer)))
new_indexer[~check] = -1
new_index = self._shallow_copy_with_infer(new_labels)
return new_index, indexer, new_indexer
# --------------------------------------------------------------------
# Join Methods
_index_shared_docs[
"join"
] = """
Compute join_index and indexers to conform data
structures to the new index.
Parameters
----------
other : Index
how : {'left', 'right', 'inner', 'outer'}
level : int or level name, default None
return_indexers : bool, default False
sort : bool, default False
Sort the join keys lexicographically in the result Index. If False,
the order of the join keys depends on the join type (how keyword).
Returns
-------
join_index, (left_indexer, right_indexer)
"""
@Appender(_index_shared_docs["join"])
def join(self, other, how="left", level=None, return_indexers=False, sort=False):
self_is_mi = isinstance(self, ABCMultiIndex)
other_is_mi = isinstance(other, ABCMultiIndex)
# try to figure out the join level
# GH3662
if level is None and (self_is_mi or other_is_mi):
# have the same levels/names so a simple join
if self.names == other.names:
pass
else:
return self._join_multi(other, how=how, return_indexers=return_indexers)
# join on the level
if level is not None and (self_is_mi or other_is_mi):
return self._join_level(
other, level, how=how, return_indexers=return_indexers
)
other = ensure_index(other)
if len(other) == 0 and how in ("left", "outer"):
join_index = self._shallow_copy()
if return_indexers:
rindexer = np.repeat(-1, len(join_index))
return join_index, None, rindexer
else:
return join_index
if len(self) == 0 and how in ("right", "outer"):
join_index = other._shallow_copy()
if return_indexers:
lindexer = np.repeat(-1, len(join_index))
return join_index, lindexer, None
else:
return join_index
if self._join_precedence < other._join_precedence:
how = {"right": "left", "left": "right"}.get(how, how)
result = other.join(
self, how=how, level=level, return_indexers=return_indexers
)
if return_indexers:
x, y, z = result
result = x, z, y
return result
if not is_dtype_equal(self.dtype, other.dtype):
this = self.astype("O")
other = other.astype("O")
return this.join(other, how=how, return_indexers=return_indexers)
_validate_join_method(how)
if not self.is_unique and not other.is_unique:
return self._join_non_unique(
other, how=how, return_indexers=return_indexers
)
elif not self.is_unique or not other.is_unique:
if self.is_monotonic and other.is_monotonic:
return self._join_monotonic(
other, how=how, return_indexers=return_indexers
)
else:
return self._join_non_unique(
other, how=how, return_indexers=return_indexers
)
elif self.is_monotonic and other.is_monotonic:
try:
return self._join_monotonic(
other, how=how, return_indexers=return_indexers
)
except TypeError:
pass
if how == "left":
join_index = self
elif how == "right":
join_index = other
elif how == "inner":
# TODO: sort=False here for backwards compat. It may
# be better to use the sort parameter passed into join
join_index = self.intersection(other, sort=False)
elif how == "outer":
# TODO: sort=True here for backwards compat. It may
# be better to use the sort parameter passed into join
join_index = self.union(other)
if sort:
join_index = join_index.sort_values()
if return_indexers:
if join_index is self:
lindexer = None
else:
lindexer = self.get_indexer(join_index)
if join_index is other:
rindexer = None
else:
rindexer = other.get_indexer(join_index)
return join_index, lindexer, rindexer
else:
return join_index
def _join_multi(self, other, how, return_indexers=True):
from .multi import MultiIndex
from pandas.core.reshape.merge import _restore_dropped_levels_multijoin
# figure out join names
self_names = set(com.not_none(*self.names))
other_names = set(com.not_none(*other.names))
overlap = self_names & other_names
# need at least 1 in common
if not overlap:
raise ValueError("cannot join with no overlapping index names")
self_is_mi = isinstance(self, MultiIndex)
other_is_mi = isinstance(other, MultiIndex)
if self_is_mi and other_is_mi:
# Drop the non-matching levels from left and right respectively
ldrop_names = list(self_names - overlap)
rdrop_names = list(other_names - overlap)
self_jnlevels = self.droplevel(ldrop_names)
other_jnlevels = other.droplevel(rdrop_names)
# Join left and right
# Join on same leveled multi-index frames is supported
join_idx, lidx, ridx = self_jnlevels.join(
other_jnlevels, how, return_indexers=True
)
# Restore the dropped levels
# Returned index level order is
# common levels, ldrop_names, rdrop_names
dropped_names = ldrop_names + rdrop_names
levels, codes, names = _restore_dropped_levels_multijoin(
self, other, dropped_names, join_idx, lidx, ridx
)
# Re-create the multi-index
multi_join_idx = MultiIndex(
levels=levels, codes=codes, names=names, verify_integrity=False
)
multi_join_idx = multi_join_idx.remove_unused_levels()
return multi_join_idx, lidx, ridx
jl = list(overlap)[0]
# Case where only one index is multi
# make the indices into mi's that match
flip_order = False
if self_is_mi:
self, other = other, self
flip_order = True
# flip if join method is right or left
how = {"right": "left", "left": "right"}.get(how, how)
level = other.names.index(jl)
result = self._join_level(
other, level, how=how, return_indexers=return_indexers
)
if flip_order:
if isinstance(result, tuple):
return result[0], result[2], result[1]
return result
def _join_non_unique(self, other, how="left", return_indexers=False):
from pandas.core.reshape.merge import _get_join_indexers
left_idx, right_idx = _get_join_indexers(
[self._ndarray_values], [other._ndarray_values], how=how, sort=True
)
left_idx = ensure_platform_int(left_idx)
right_idx = ensure_platform_int(right_idx)
join_index = np.asarray(self._ndarray_values.take(left_idx))
mask = left_idx == -1
np.putmask(join_index, mask, other._ndarray_values.take(right_idx))
join_index = self._wrap_joined_index(join_index, other)
if return_indexers:
return join_index, left_idx, right_idx
else:
return join_index
def _join_level(
self, other, level, how="left", return_indexers=False, keep_order=True
):
"""
The join method *only* affects the level of the resulting
MultiIndex. Otherwise it just exactly aligns the Index data to the
labels of the level in the MultiIndex.
If ```keep_order == True```, the order of the data indexed by the
MultiIndex will not be changed; otherwise, it will tie out
with `other`.
"""
from .multi import MultiIndex
def _get_leaf_sorter(labels):
"""
Returns sorter for the inner most level while preserving the
order of higher levels.
"""
if labels[0].size == 0:
return np.empty(0, dtype="int64")
if len(labels) == 1:
lab = ensure_int64(labels[0])
sorter, _ = libalgos.groupsort_indexer(lab, 1 + lab.max())
return sorter
# find indexers of beginning of each set of
# same-key labels w.r.t all but last level
tic = labels[0][:-1] != labels[0][1:]
for lab in labels[1:-1]:
tic |= lab[:-1] != lab[1:]
starts = np.hstack(([True], tic, [True])).nonzero()[0]
lab = ensure_int64(labels[-1])
return lib.get_level_sorter(lab, ensure_int64(starts))
if isinstance(self, MultiIndex) and isinstance(other, MultiIndex):
raise TypeError("Join on level between two MultiIndex objects is ambiguous")
left, right = self, other
flip_order = not isinstance(self, MultiIndex)
if flip_order:
left, right = right, left
how = {"right": "left", "left": "right"}.get(how, how)
level = left._get_level_number(level)
old_level = left.levels[level]
if not right.is_unique:
raise NotImplementedError(
"Index._join_level on non-unique index is not implemented"
)
new_level, left_lev_indexer, right_lev_indexer = old_level.join(
right, how=how, return_indexers=True
)
if left_lev_indexer is None:
if keep_order or len(left) == 0:
left_indexer = None
join_index = left
else: # sort the leaves
left_indexer = _get_leaf_sorter(left.codes[: level + 1])
join_index = left[left_indexer]
else:
left_lev_indexer = ensure_int64(left_lev_indexer)
rev_indexer = lib.get_reverse_indexer(left_lev_indexer, len(old_level))
new_lev_codes = algos.take_nd(
rev_indexer, left.codes[level], allow_fill=False
)
new_codes = list(left.codes)
new_codes[level] = new_lev_codes
new_levels = list(left.levels)
new_levels[level] = new_level
if keep_order: # just drop missing values. o.w. keep order
left_indexer = np.arange(len(left), dtype=np.intp)
mask = new_lev_codes != -1
if not mask.all():
new_codes = [lab[mask] for lab in new_codes]
left_indexer = left_indexer[mask]
else: # tie out the order with other
if level == 0: # outer most level, take the fast route
ngroups = 1 + new_lev_codes.max()
left_indexer, counts = libalgos.groupsort_indexer(
new_lev_codes, ngroups
)
# missing values are placed first; drop them!
left_indexer = left_indexer[counts[0] :]
new_codes = [lab[left_indexer] for lab in new_codes]
else: # sort the leaves
mask = new_lev_codes != -1
mask_all = mask.all()
if not mask_all:
new_codes = [lab[mask] for lab in new_codes]
left_indexer = _get_leaf_sorter(new_codes[: level + 1])
new_codes = [lab[left_indexer] for lab in new_codes]
# left_indexers are w.r.t masked frame.
# reverse to original frame!
if not mask_all:
left_indexer = mask.nonzero()[0][left_indexer]
join_index = MultiIndex(
levels=new_levels,
codes=new_codes,
names=left.names,
verify_integrity=False,
)
if right_lev_indexer is not None:
right_indexer = algos.take_nd(
right_lev_indexer, join_index.codes[level], allow_fill=False
)
else:
right_indexer = join_index.codes[level]
if flip_order:
left_indexer, right_indexer = right_indexer, left_indexer
if return_indexers:
left_indexer = (
None if left_indexer is None else ensure_platform_int(left_indexer)
)
right_indexer = (
None if right_indexer is None else ensure_platform_int(right_indexer)
)
return join_index, left_indexer, right_indexer
else:
return join_index
def _join_monotonic(self, other, how="left", return_indexers=False):
if self.equals(other):
ret_index = other if how == "right" else self
if return_indexers:
return ret_index, None, None
else:
return ret_index
sv = self._ndarray_values
ov = other._ndarray_values
if self.is_unique and other.is_unique:
# We can perform much better than the general case
if how == "left":
join_index = self
lidx = None
ridx = self._left_indexer_unique(sv, ov)
elif how == "right":
join_index = other
lidx = self._left_indexer_unique(ov, sv)
ridx = None
elif how == "inner":
join_index, lidx, ridx = self._inner_indexer(sv, ov)
join_index = self._wrap_joined_index(join_index, other)
elif how == "outer":
join_index, lidx, ridx = self._outer_indexer(sv, ov)
join_index = self._wrap_joined_index(join_index, other)
else:
if how == "left":
join_index, lidx, ridx = self._left_indexer(sv, ov)
elif how == "right":
join_index, ridx, lidx = self._left_indexer(ov, sv)
elif how == "inner":
join_index, lidx, ridx = self._inner_indexer(sv, ov)
elif how == "outer":
join_index, lidx, ridx = self._outer_indexer(sv, ov)
join_index = self._wrap_joined_index(join_index, other)
if return_indexers:
lidx = None if lidx is None else ensure_platform_int(lidx)
ridx = None if ridx is None else ensure_platform_int(ridx)
return join_index, lidx, ridx
else:
return join_index
def _wrap_joined_index(self, joined, other):
name = get_op_result_name(self, other)
return Index(joined, name=name)
# --------------------------------------------------------------------
# Uncategorized Methods
@property
def values(self):
"""
Return an array representing the data in the Index.
.. warning::
We recommend using :attr:`Index.array` or
:meth:`Index.to_numpy`, depending on whether you need
a reference to the underlying data or a NumPy array.
Returns
-------
array: numpy.ndarray or ExtensionArray
See Also
--------
Index.array : Reference to the underlying data.
Index.to_numpy : A NumPy array representing the underlying data.
"""
return self._data.view(np.ndarray)
@property
def _values(self) -> Union[ExtensionArray, ABCIndexClass, np.ndarray]:
# TODO(EA): remove index types as they become extension arrays
"""
The best array representation.
This is an ndarray, ExtensionArray, or Index subclass. This differs
from ``_ndarray_values``, which always returns an ndarray.
Both ``_values`` and ``_ndarray_values`` are consistent between
``Series`` and ``Index``.
It may differ from the public '.values' method.
index | values | _values | _ndarray_values |
----------------- | --------------- | ------------- | --------------- |
Index | ndarray | ndarray | ndarray |
CategoricalIndex | Categorical | Categorical | ndarray[int] |
DatetimeIndex | ndarray[M8ns] | ndarray[M8ns] | ndarray[M8ns] |
DatetimeIndex[tz] | ndarray[M8ns] | DTI[tz] | ndarray[M8ns] |
PeriodIndex | ndarray[object] | PeriodArray | ndarray[int] |
IntervalIndex | IntervalArray | IntervalArray | ndarray[object] |
See Also
--------
values
_ndarray_values
"""
return self._data
def _internal_get_values(self):
"""
Return `Index` data as an `numpy.ndarray`.
Returns
-------
numpy.ndarray
A one-dimensional numpy array of the `Index` values.
See Also
--------
Index.values : The attribute that _internal_get_values wraps.
Examples
--------
Getting the `Index` values of a `DataFrame`:
>>> df = pd.DataFrame([[1, 2, 3], [4, 5, 6], [7, 8, 9]],
... index=['a', 'b', 'c'], columns=['A', 'B', 'C'])
>>> df
A B C
a 1 2 3
b 4 5 6
c 7 8 9
>>> df.index._internal_get_values()
array(['a', 'b', 'c'], dtype=object)
Standalone `Index` values:
>>> idx = pd.Index(['1', '2', '3'])
>>> idx._internal_get_values()
array(['1', '2', '3'], dtype=object)
`MultiIndex` arrays also have only one dimension:
>>> midx = pd.MultiIndex.from_arrays([[1, 2, 3], ['a', 'b', 'c']],
... names=('number', 'letter'))
>>> midx._internal_get_values()
array([(1, 'a'), (2, 'b'), (3, 'c')], dtype=object)
>>> midx._internal_get_values().ndim
1
"""
return self.values
@Appender(IndexOpsMixin.memory_usage.__doc__)
def memory_usage(self, deep=False):
result = super().memory_usage(deep=deep)
# include our engine hashtable
result += self._engine.sizeof(deep=deep)
return result
_index_shared_docs[
"where"
] = """
Return an Index of same shape as self and whose corresponding
entries are from self where cond is True and otherwise are from
other.
Parameters
----------
cond : bool array-like with the same length as self
other : scalar, or array-like
Returns
-------
Index
"""
@Appender(_index_shared_docs["where"])
def where(self, cond, other=None):
if other is None:
other = self._na_value
dtype = self.dtype
values = self.values
if is_bool(other) or is_bool_dtype(other):
# bools force casting
values = values.astype(object)
dtype = None
values = np.where(cond, values, other)
if self._is_numeric_dtype and np.any(isna(values)):
# We can't coerce to the numeric dtype of "self" (unless
# it's float) if there are NaN values in our output.
dtype = None
return self._shallow_copy_with_infer(values, dtype=dtype)
# construction helpers
@classmethod
def _try_convert_to_int_index(cls, data, copy, name, dtype):
"""
Attempt to convert an array of data into an integer index.
Parameters
----------
data : The data to convert.
copy : Whether to copy the data or not.
name : The name of the index returned.
Returns
-------
int_index : data converted to either an Int64Index or a
UInt64Index
Raises
------
ValueError if the conversion was not successful.
"""
from .numeric import Int64Index, UInt64Index
if not is_unsigned_integer_dtype(dtype):
# skip int64 conversion attempt if uint-like dtype is passed, as
# this could return Int64Index when UInt64Index is what's desired
try:
res = data.astype("i8", copy=False)
if (res == data).all():
return Int64Index(res, copy=copy, name=name)
except (OverflowError, TypeError, ValueError):
pass
# Conversion to int64 failed (possibly due to overflow) or was skipped,
# so let's try now with uint64.
try:
res = data.astype("u8", copy=False)
if (res == data).all():
return UInt64Index(res, copy=copy, name=name)
except (OverflowError, TypeError, ValueError):
pass
raise ValueError
@classmethod
def _scalar_data_error(cls, data):
# We return the TypeError so that we can raise it from the constructor
# in order to keep mypy happy
return TypeError(
f"{cls.__name__}(...) must be called with a collection of some "
f"kind, {repr(data)} was passed"
)
@classmethod
def _string_data_error(cls, data):
raise TypeError(
"String dtype not supported, you may need "
"to explicitly cast to a numeric type"
)
def _coerce_scalar_to_index(self, item):
"""
We need to coerce a scalar to a compat for our index type.
Parameters
----------
item : scalar item to coerce
"""
dtype = self.dtype
if self._is_numeric_dtype and isna(item):
# We can't coerce to the numeric dtype of "self" (unless
# it's float) if there are NaN values in our output.
dtype = None
return Index([item], dtype=dtype, **self._get_attributes_dict())
def _to_safe_for_reshape(self):
"""
Convert to object if we are a categorical.
"""
return self
def _convert_for_op(self, value):
"""
Convert value to be insertable to ndarray.
"""
return value
def _assert_can_do_op(self, value):
"""
Check value is valid for scalar op.
"""
if not is_scalar(value):
raise TypeError(f"'value' must be a scalar, passed: {type(value).__name__}")
def _is_memory_usage_qualified(self) -> bool:
"""
Return a boolean if we need a qualified .info display.
"""
return self.is_object()
def is_type_compatible(self, kind) -> bool:
"""
Whether the index type is compatible with the provided type.
"""
return kind == self.inferred_type
_index_shared_docs[
"contains"
] = """
Return a boolean indicating whether the provided key is in the index.
Parameters
----------
key : label
The key to check if it is present in the index.
Returns
-------
bool
Whether the key search is in the index.
See Also
--------
Index.isin : Returns an ndarray of boolean dtype indicating whether the
list-like key is in the index.
Examples
--------
>>> idx = pd.Index([1, 2, 3, 4])
>>> idx
Int64Index([1, 2, 3, 4], dtype='int64')
>>> 2 in idx
True
>>> 6 in idx
False
"""
@Appender(_index_shared_docs["contains"] % _index_doc_kwargs)
def __contains__(self, key) -> bool:
hash(key)
try:
return key in self._engine
except (OverflowError, TypeError, ValueError):
return False
def __hash__(self):
raise TypeError(f"unhashable type: {repr(type(self).__name__)}")
def __setitem__(self, key, value):
raise TypeError("Index does not support mutable operations")
def __getitem__(self, key):
"""
Override numpy.ndarray's __getitem__ method to work as desired.
This function adds lists and Series as valid boolean indexers
(ndarrays only supports ndarray with dtype=bool).
If resulting ndim != 1, plain ndarray is returned instead of
corresponding `Index` subclass.
"""
# There's no custom logic to be implemented in __getslice__, so it's
# not overloaded intentionally.
getitem = self._data.__getitem__
promote = self._shallow_copy
if is_scalar(key):
key = com.cast_scalar_indexer(key)
return getitem(key)
if isinstance(key, slice):
# This case is separated from the conditional above to avoid
# pessimization of basic indexing.
return promote(getitem(key))
if com.is_bool_indexer(key):
key = np.asarray(key, dtype=bool)
key = com.values_from_object(key)
result = getitem(key)
if not is_scalar(result):
return promote(result)
else:
return result
def _can_hold_identifiers_and_holds_name(self, name) -> bool:
"""
Faster check for ``name in self`` when we know `name` is a Python
identifier (e.g. in NDFrame.__getattr__, which hits this to support
. key lookup). For indexes that can't hold identifiers (everything
but object & categorical) we just return False.
https://github.com/pandas-dev/pandas/issues/19764
"""
if self.is_object() or self.is_categorical():
return name in self
return False
def append(self, other):
"""
Append a collection of Index options together.
Parameters
----------
other : Index or list/tuple of indices
Returns
-------
appended : Index
"""
to_concat = [self]
if isinstance(other, (list, tuple)):
to_concat = to_concat + list(other)
else:
to_concat.append(other)
for obj in to_concat:
if not isinstance(obj, Index):
raise TypeError("all inputs must be Index")
names = {obj.name for obj in to_concat}
name = None if len(names) > 1 else self.name
return self._concat(to_concat, name)
def _concat(self, to_concat, name):
typs = _concat.get_dtype_kinds(to_concat)
if len(typs) == 1:
return self._concat_same_dtype(to_concat, name=name)
return Index._concat_same_dtype(self, to_concat, name=name)
def _concat_same_dtype(self, to_concat, name):
"""
Concatenate to_concat which has the same class.
"""
# must be overridden in specific classes
klasses = (
ABCDatetimeIndex,
ABCTimedeltaIndex,
ABCPeriodIndex,
ExtensionArray,
ABCIntervalIndex,
)
to_concat = [
x.astype(object) if isinstance(x, klasses) else x for x in to_concat
]
self = to_concat[0]
attribs = self._get_attributes_dict()
attribs["name"] = name
to_concat = [x._values if isinstance(x, Index) else x for x in to_concat]
return self._shallow_copy_with_infer(np.concatenate(to_concat), **attribs)
def putmask(self, mask, value):
"""
Return a new Index of the values set with the mask.
Returns
-------
Index
See Also
--------
numpy.ndarray.putmask
"""
values = self.values.copy()
try:
np.putmask(values, mask, self._convert_for_op(value))
return self._shallow_copy(values)
except (ValueError, TypeError) as err:
if is_object_dtype(self):
raise err
# coerces to object
return self.astype(object).putmask(mask, value)
def equals(self, other) -> bool:
"""
Determine if two Index objects contain the same elements.
Returns
-------
bool
True if "other" is an Index and it has the same elements as calling
index; False otherwise.
"""
if self.is_(other):
return True
if not isinstance(other, Index):
return False
if is_object_dtype(self) and not is_object_dtype(other):
# if other is not object, use other's logic for coercion
return other.equals(self)
if isinstance(other, ABCMultiIndex):
# d-level MultiIndex can equal d-tuple Index
if not is_object_dtype(self.dtype):
if self.nlevels != other.nlevels:
return False
return array_equivalent(
com.values_from_object(self), com.values_from_object(other)
)
def identical(self, other) -> bool:
"""
Similar to equals, but check that other comparable attributes are
also equal.
Returns
-------
bool
If two Index objects have equal elements and same type True,
otherwise False.
"""
return (
self.equals(other)
and all(
(
getattr(self, c, None) == getattr(other, c, None)
for c in self._comparables
)
)
and type(self) == type(other)
)
def asof(self, label):
"""
Return the label from the index, or, if not present, the previous one.
Assuming that the index is sorted, return the passed index label if it
is in the index, or return the previous index label if the passed one
is not in the index.
Parameters
----------
label : object
The label up to which the method returns the latest index label.
Returns
-------
object
The passed label if it is in the index. The previous label if the
passed label is not in the sorted index or `NaN` if there is no
such label.
See Also
--------
Series.asof : Return the latest value in a Series up to the
passed index.
merge_asof : Perform an asof merge (similar to left join but it
matches on nearest key rather than equal key).
Index.get_loc : An `asof` is a thin wrapper around `get_loc`
with method='pad'.
Examples
--------
`Index.asof` returns the latest index label up to the passed label.
>>> idx = pd.Index(['2013-12-31', '2014-01-02', '2014-01-03'])
>>> idx.asof('2014-01-01')
'2013-12-31'
If the label is in the index, the method returns the passed label.
>>> idx.asof('2014-01-02')
'2014-01-02'
If all of the labels in the index are later than the passed label,
NaN is returned.
>>> idx.asof('1999-01-02')
nan
If the index is not sorted, an error is raised.
>>> idx_not_sorted = pd.Index(['2013-12-31', '2015-01-02',
... '2014-01-03'])
>>> idx_not_sorted.asof('2013-12-31')
Traceback (most recent call last):
ValueError: index must be monotonic increasing or decreasing
"""
try:
loc = self.get_loc(label, method="pad")
except KeyError:
return self._na_value
else:
if isinstance(loc, slice):
loc = loc.indices(len(self))[-1]
return self[loc]
def asof_locs(self, where, mask):
"""
Find the locations (indices) of the labels from the index for
every entry in the `where` argument.
As in the `asof` function, if the label (a particular entry in
`where`) is not in the index, the latest index label up to the
passed label is chosen and its index returned.
If all of the labels in the index are later than a label in `where`,
-1 is returned.
`mask` is used to ignore NA values in the index during calculation.
Parameters
----------
where : Index
An Index consisting of an array of timestamps.
mask : array-like
Array of booleans denoting where values in the original
data are not NA.
Returns
-------
numpy.ndarray
An array of locations (indices) of the labels from the Index
which correspond to the return values of the `asof` function
for every element in `where`.
"""
locs = self.values[mask].searchsorted(where.values, side="right")
locs = np.where(locs > 0, locs - 1, 0)
result = np.arange(len(self))[mask].take(locs)
first = mask.argmax()
result[(locs == 0) & (where.values < self.values[first])] = -1
return result
def sort_values(self, return_indexer=False, ascending=True):
"""
Return a sorted copy of the index.
Return a sorted copy of the index, and optionally return the indices
that sorted the index itself.
Parameters
----------
return_indexer : bool, default False
Should the indices that would sort the index be returned.
ascending : bool, default True
Should the index values be sorted in an ascending order.
Returns
-------
sorted_index : pandas.Index
Sorted copy of the index.
indexer : numpy.ndarray, optional
The indices that the index itself was sorted by.
See Also
--------
Series.sort_values : Sort values of a Series.
DataFrame.sort_values : Sort values in a DataFrame.
Examples
--------
>>> idx = pd.Index([10, 100, 1, 1000])
>>> idx
Int64Index([10, 100, 1, 1000], dtype='int64')
Sort values in ascending order (default behavior).
>>> idx.sort_values()
Int64Index([1, 10, 100, 1000], dtype='int64')
Sort values in descending order, and also get the indices `idx` was
sorted by.
>>> idx.sort_values(ascending=False, return_indexer=True)
(Int64Index([1000, 100, 10, 1], dtype='int64'), array([3, 1, 0, 2]))
"""
_as = self.argsort()
if not ascending:
_as = _as[::-1]
sorted_index = self.take(_as)
if return_indexer:
return sorted_index, _as
else:
return sorted_index
def sort(self, *args, **kwargs):
"""
Use sort_values instead.
"""
raise TypeError("cannot sort an Index object in-place, use sort_values instead")
def shift(self, periods=1, freq=None):
"""
Shift index by desired number of time frequency increments.
This method is for shifting the values of datetime-like indexes
by a specified time increment a given number of times.
Parameters
----------
periods : int, default 1
Number of periods (or increments) to shift by,
can be positive or negative.
freq : pandas.DateOffset, pandas.Timedelta or str, optional
Frequency increment to shift by.
If None, the index is shifted by its own `freq` attribute.
Offset aliases are valid strings, e.g., 'D', 'W', 'M' etc.
Returns
-------
pandas.Index
Shifted index.
See Also
--------
Series.shift : Shift values of Series.
Notes
-----
This method is only implemented for datetime-like index classes,
i.e., DatetimeIndex, PeriodIndex and TimedeltaIndex.
Examples
--------
Put the first 5 month starts of 2011 into an index.
>>> month_starts = pd.date_range('1/1/2011', periods=5, freq='MS')
>>> month_starts
DatetimeIndex(['2011-01-01', '2011-02-01', '2011-03-01', '2011-04-01',
'2011-05-01'],
dtype='datetime64[ns]', freq='MS')
Shift the index by 10 days.
>>> month_starts.shift(10, freq='D')
DatetimeIndex(['2011-01-11', '2011-02-11', '2011-03-11', '2011-04-11',
'2011-05-11'],
dtype='datetime64[ns]', freq=None)
The default value of `freq` is the `freq` attribute of the index,
which is 'MS' (month start) in this example.
>>> month_starts.shift(10)
DatetimeIndex(['2011-11-01', '2011-12-01', '2012-01-01', '2012-02-01',
'2012-03-01'],
dtype='datetime64[ns]', freq='MS')
"""
raise NotImplementedError(f"Not supported for type {type(self).__name__}")
def argsort(self, *args, **kwargs):
"""
Return the integer indices that would sort the index.
Parameters
----------
*args
Passed to `numpy.ndarray.argsort`.
**kwargs
Passed to `numpy.ndarray.argsort`.
Returns
-------
numpy.ndarray
Integer indices that would sort the index if used as
an indexer.
See Also
--------
numpy.argsort : Similar method for NumPy arrays.
Index.sort_values : Return sorted copy of Index.
Examples
--------
>>> idx = pd.Index(['b', 'a', 'd', 'c'])
>>> idx
Index(['b', 'a', 'd', 'c'], dtype='object')
>>> order = idx.argsort()
>>> order
array([1, 0, 3, 2])
>>> idx[order]
Index(['a', 'b', 'c', 'd'], dtype='object')
"""
result = self.asi8
if result is None:
result = np.array(self)
return result.argsort(*args, **kwargs)
_index_shared_docs[
"get_value"
] = """
Fast lookup of value from 1-dimensional ndarray. Only use this if you
know what you're doing.
Returns
-------
scalar
A value in the Series with the index of the key value in self.
"""
@Appender(_index_shared_docs["get_value"] % _index_doc_kwargs)
def get_value(self, series, key):
# if we have something that is Index-like, then
# use this, e.g. DatetimeIndex
# Things like `Series._get_value` (via .at) pass the EA directly here.
s = extract_array(series, extract_numpy=True)
if isinstance(s, ExtensionArray):
if is_scalar(key):
# GH 20882, 21257
# First try to convert the key to a location
# If that fails, raise a KeyError if an integer
# index, otherwise, see if key is an integer, and
# try that
try:
iloc = self.get_loc(key)
return s[iloc]
except KeyError:
if len(self) > 0 and (self.holds_integer() or self.is_boolean()):
raise
elif is_integer(key):
return s[key]
else:
# if key is not a scalar, directly raise an error (the code below
# would convert to numpy arrays and raise later any way) - GH29926
raise InvalidIndexError(key)
s = com.values_from_object(series)
k = com.values_from_object(key)
k = self._convert_scalar_indexer(k, kind="getitem")
try:
return self._engine.get_value(s, k, tz=getattr(series.dtype, "tz", None))
except KeyError as e1:
if len(self) > 0 and (self.holds_integer() or self.is_boolean()):
raise
try:
return libindex.get_value_at(s, key)
except IndexError:
raise
except TypeError:
# generator/iterator-like
if is_iterator(key):
raise InvalidIndexError(key)
else:
raise e1
except Exception:
raise e1
except TypeError:
# e.g. "[False] is an invalid key"
if is_scalar(key):
raise IndexError(key)
raise InvalidIndexError(key)
def set_value(self, arr, key, value):
"""
Fast lookup of value from 1-dimensional ndarray.
.. deprecated:: 1.0
Notes
-----
Only use this if you know what you're doing.
"""
warnings.warn(
(
"The 'set_value' method is deprecated, and "
"will be removed in a future version."
),
FutureWarning,
stacklevel=2,
)
self._engine.set_value(
com.values_from_object(arr), com.values_from_object(key), value
)
_index_shared_docs[
"get_indexer_non_unique"
] = """
Compute indexer and mask for new index given the current index. The
indexer should be then used as an input to ndarray.take to align the
current data to the new index.
Parameters
----------
target : %(target_klass)s
Returns
-------
indexer : ndarray of int
Integers from 0 to n - 1 indicating that the index at these
positions matches the corresponding target values. Missing values
in the target are marked by -1.
missing : ndarray of int
An indexer into the target of the values not found.
These correspond to the -1 in the indexer array.
"""
@Appender(_index_shared_docs["get_indexer_non_unique"] % _index_doc_kwargs)
def get_indexer_non_unique(self, target):
target = ensure_index(target)
pself, ptarget = self._maybe_promote(target)
if pself is not self or ptarget is not target:
return pself.get_indexer_non_unique(ptarget)
if is_categorical(target):
tgt_values = np.asarray(target)
elif self.is_all_dates:
tgt_values = target.asi8
else:
tgt_values = target._ndarray_values
indexer, missing = self._engine.get_indexer_non_unique(tgt_values)
return ensure_platform_int(indexer), missing
def get_indexer_for(self, target, **kwargs):
"""
Guaranteed return of an indexer even when non-unique.
This dispatches to get_indexer or get_indexer_non_unique
as appropriate.
Returns
-------
numpy.ndarray
List of indices.
"""
if self.is_unique:
return self.get_indexer(target, **kwargs)
indexer, _ = self.get_indexer_non_unique(target, **kwargs)
return indexer
def _maybe_promote(self, other):
# A hack, but it works
if self.inferred_type == "date" and isinstance(other, ABCDatetimeIndex):
return type(other)(self), other
elif self.inferred_type == "boolean":
if not is_object_dtype(self.dtype):
return self.astype("object"), other.astype("object")
return self, other
def groupby(self, values):
"""
Group the index labels by a given array of values.
Parameters
----------
values : array
Values used to determine the groups.
Returns
-------
groups : dict
{group name -> group labels}
"""
# TODO: if we are a MultiIndex, we can do better
# that converting to tuples
if isinstance(values, ABCMultiIndex):
values = values.values
values = ensure_categorical(values)
result = values._reverse_indexer()
# map to the label
result = {k: self.take(v) for k, v in result.items()}
return result
def map(self, mapper, na_action=None):
"""
Map values using input correspondence (a dict, Series, or function).
Parameters
----------
mapper : function, dict, or Series
Mapping correspondence.
na_action : {None, 'ignore'}
If 'ignore', propagate NA values, without passing them to the
mapping correspondence.
Returns
-------
applied : Union[Index, MultiIndex], inferred
The output of the mapping function applied to the index.
If the function returns a tuple with more than one element
a MultiIndex will be returned.
"""
from .multi import MultiIndex
new_values = super()._map_values(mapper, na_action=na_action)
attributes = self._get_attributes_dict()
# we can return a MultiIndex
if new_values.size and isinstance(new_values[0], tuple):
if isinstance(self, MultiIndex):
names = self.names
elif attributes.get("name"):
names = [attributes.get("name")] * len(new_values[0])
else:
names = None
return MultiIndex.from_tuples(new_values, names=names)
attributes["copy"] = False
if not new_values.size:
# empty
attributes["dtype"] = self.dtype
return Index(new_values, **attributes)
def isin(self, values, level=None):
"""
Return a boolean array where the index values are in `values`.
Compute boolean array of whether each index value is found in the
passed set of values. The length of the returned boolean array matches
the length of the index.
Parameters
----------
values : set or list-like
Sought values.
level : str or int, optional
Name or position of the index level to use (if the index is a
`MultiIndex`).
Returns
-------
is_contained : ndarray
NumPy array of boolean values.
See Also
--------
Series.isin : Same for Series.
DataFrame.isin : Same method for DataFrames.
Notes
-----
In the case of `MultiIndex` you must either specify `values` as a
list-like object containing tuples that are the same length as the
number of levels, or specify `level`. Otherwise it will raise a
``ValueError``.
If `level` is specified:
- if it is the name of one *and only one* index level, use that level;
- otherwise it should be a number indicating level position.
Examples
--------
>>> idx = pd.Index([1,2,3])
>>> idx
Int64Index([1, 2, 3], dtype='int64')
Check whether each index value in a list of values.
>>> idx.isin([1, 4])
array([ True, False, False])
>>> midx = pd.MultiIndex.from_arrays([[1,2,3],
... ['red', 'blue', 'green']],
... names=('number', 'color'))
>>> midx
MultiIndex(levels=[[1, 2, 3], ['blue', 'green', 'red']],
codes=[[0, 1, 2], [2, 0, 1]],
names=['number', 'color'])
Check whether the strings in the 'color' level of the MultiIndex
are in a list of colors.
>>> midx.isin(['red', 'orange', 'yellow'], level='color')
array([ True, False, False])
To check across the levels of a MultiIndex, pass a list of tuples:
>>> midx.isin([(1, 'red'), (3, 'red')])
array([ True, False, False])
For a DatetimeIndex, string values in `values` are converted to
Timestamps.
>>> dates = ['2000-03-11', '2000-03-12', '2000-03-13']
>>> dti = pd.to_datetime(dates)
>>> dti
DatetimeIndex(['2000-03-11', '2000-03-12', '2000-03-13'],
dtype='datetime64[ns]', freq=None)
>>> dti.isin(['2000-03-11'])
array([ True, False, False])
"""
if level is not None:
self._validate_index_level(level)
return algos.isin(self, values)
def _get_string_slice(self, key, use_lhs=True, use_rhs=True):
# this is for partial string indexing,
# overridden in DatetimeIndex, TimedeltaIndex and PeriodIndex
raise NotImplementedError
def slice_indexer(self, start=None, end=None, step=None, kind=None):
"""
For an ordered or unique index, compute the slice indexer for input
labels and step.
Parameters
----------
start : label, default None
If None, defaults to the beginning.
end : label, default None
If None, defaults to the end.
step : int, default None
kind : str, default None
Returns
-------
indexer : slice
Raises
------
KeyError : If key does not exist, or key is not unique and index is
not ordered.
Notes
-----
This function assumes that the data is sorted, so use at your own peril
Examples
--------
This is a method on all index types. For example you can do:
>>> idx = pd.Index(list('abcd'))
>>> idx.slice_indexer(start='b', end='c')
slice(1, 3)
>>> idx = pd.MultiIndex.from_arrays([list('abcd'), list('efgh')])
>>> idx.slice_indexer(start='b', end=('c', 'g'))
slice(1, 3)
"""
start_slice, end_slice = self.slice_locs(start, end, step=step, kind=kind)
# return a slice
if not is_scalar(start_slice):
raise AssertionError("Start slice bound is non-scalar")
if not is_scalar(end_slice):
raise AssertionError("End slice bound is non-scalar")
return slice(start_slice, end_slice, step)
def _maybe_cast_indexer(self, key):
"""
If we have a float key and are not a floating index, then try to cast
to an int if equivalent.
"""
if is_float(key) and not self.is_floating():
try:
ckey = int(key)
if ckey == key:
key = ckey
except (OverflowError, ValueError, TypeError):
pass
return key
def _validate_indexer(self, form, key, kind):
"""
If we are positional indexer, validate that we have appropriate
typed bounds must be an integer.
"""
assert kind in ["ix", "loc", "getitem", "iloc"]
if key is None:
pass
elif is_integer(key):
pass
elif kind in ["iloc", "getitem"]:
self._invalid_indexer(form, key)
return key
_index_shared_docs[
"_maybe_cast_slice_bound"
] = """
This function should be overloaded in subclasses that allow non-trivial
casting on label-slice bounds, e.g. datetime-like indices allowing
strings containing formatted datetimes.
Parameters
----------
label : object
side : {'left', 'right'}
kind : {'ix', 'loc', 'getitem'}
Returns
-------
label : object
Notes
-----
Value of `side` parameter should be validated in caller.
"""
@Appender(_index_shared_docs["_maybe_cast_slice_bound"])
def _maybe_cast_slice_bound(self, label, side, kind):
assert kind in ["ix", "loc", "getitem", None]
# We are a plain index here (sub-class override this method if they
# wish to have special treatment for floats/ints, e.g. Float64Index and
# datetimelike Indexes
# reject them
if is_float(label):
if not (kind in ["ix"] and (self.holds_integer() or self.is_floating())):
self._invalid_indexer("slice", label)
# we are trying to find integer bounds on a non-integer based index
# this is rejected (generally .loc gets you here)
elif is_integer(label):
self._invalid_indexer("slice", label)
return label
def _searchsorted_monotonic(self, label, side="left"):
if self.is_monotonic_increasing:
return self.searchsorted(label, side=side)
elif self.is_monotonic_decreasing:
# np.searchsorted expects ascending sort order, have to reverse
# everything for it to work (element ordering, search side and
# resulting value).
pos = self[::-1].searchsorted(
label, side="right" if side == "left" else "left"
)
return len(self) - pos
raise ValueError("index must be monotonic increasing or decreasing")
def get_slice_bound(self, label, side, kind):
"""
Calculate slice bound that corresponds to given label.
Returns leftmost (one-past-the-rightmost if ``side=='right'``) position
of given label.
Parameters
----------
label : object
side : {'left', 'right'}
kind : {'ix', 'loc', 'getitem'}
Returns
-------
int
Index of label.
"""
assert kind in ["ix", "loc", "getitem", None]
if side not in ("left", "right"):
raise ValueError(
f"Invalid value for side kwarg, must be either"
f" 'left' or 'right': {side}"
)
original_label = label
# For datetime indices label may be a string that has to be converted
# to datetime boundary according to its resolution.
label = self._maybe_cast_slice_bound(label, side, kind)
# we need to look up the label
try:
slc = self.get_loc(label)
except KeyError as err:
try:
return self._searchsorted_monotonic(label, side)
except ValueError:
# raise the original KeyError
raise err
if isinstance(slc, np.ndarray):
# get_loc may return a boolean array or an array of indices, which
# is OK as long as they are representable by a slice.
if is_bool_dtype(slc):
slc = lib.maybe_booleans_to_slice(slc.view("u1"))
else:
slc = lib.maybe_indices_to_slice(slc.astype("i8"), len(self))
if isinstance(slc, np.ndarray):
raise KeyError(
f"Cannot get {side} slice bound for non-unique "
f"label: {repr(original_label)}"
)
if isinstance(slc, slice):
if side == "left":
return slc.start
else:
return slc.stop
else:
if side == "right":
return slc + 1
else:
return slc
def slice_locs(self, start=None, end=None, step=None, kind=None):
"""
Compute slice locations for input labels.
Parameters
----------
start : label, default None
If None, defaults to the beginning.
end : label, default None
If None, defaults to the end.
step : int, defaults None
If None, defaults to 1.
kind : {'ix', 'loc', 'getitem'} or None
Returns
-------
start, end : int
See Also
--------
Index.get_loc : Get location for a single label.
Notes
-----
This method only works if the index is monotonic or unique.
Examples
--------
>>> idx = pd.Index(list('abcd'))
>>> idx.slice_locs(start='b', end='c')
(1, 3)
"""
inc = step is None or step >= 0
if not inc:
# If it's a reverse slice, temporarily swap bounds.
start, end = end, start
# GH 16785: If start and end happen to be date strings with UTC offsets
# attempt to parse and check that the offsets are the same
if isinstance(start, (str, datetime)) and isinstance(end, (str, datetime)):
try:
ts_start = Timestamp(start)
ts_end = Timestamp(end)
except (ValueError, TypeError):
pass
else:
if not tz_compare(ts_start.tzinfo, ts_end.tzinfo):
raise ValueError("Both dates must have the same UTC offset")
start_slice = None
if start is not None:
start_slice = self.get_slice_bound(start, "left", kind)
if start_slice is None:
start_slice = 0
end_slice = None
if end is not None:
end_slice = self.get_slice_bound(end, "right", kind)
if end_slice is None:
end_slice = len(self)
if not inc:
# Bounds at this moment are swapped, swap them back and shift by 1.
#
# slice_locs('B', 'A', step=-1): s='B', e='A'
#
# s='A' e='B'
# AFTER SWAP: | |
# v ------------------> V
# -----------------------------------
# | | |A|A|A|A| | | | | |B|B| | | | |
# -----------------------------------
# ^ <------------------ ^
# SHOULD BE: | |
# end=s-1 start=e-1
#
end_slice, start_slice = start_slice - 1, end_slice - 1
# i == -1 triggers ``len(self) + i`` selection that points to the
# last element, not before-the-first one, subtracting len(self)
# compensates that.
if end_slice == -1:
end_slice -= len(self)
if start_slice == -1:
start_slice -= len(self)
return start_slice, end_slice
def delete(self, loc):
"""
Make new Index with passed location(-s) deleted.
Returns
-------
new_index : Index
"""
return self._shallow_copy(np.delete(self._data, loc))
def insert(self, loc, item):
"""
Make new Index inserting new item at location.
Follows Python list.append semantics for negative values.
Parameters
----------
loc : int
item : object
Returns
-------
new_index : Index
"""
_self = np.asarray(self)
item = self._coerce_scalar_to_index(item)._ndarray_values
idx = np.concatenate((_self[:loc], item, _self[loc:]))
return self._shallow_copy_with_infer(idx)
def drop(self, labels, errors="raise"):
"""
Make new Index with passed list of labels deleted.
Parameters
----------
labels : array-like
errors : {'ignore', 'raise'}, default 'raise'
If 'ignore', suppress error and existing labels are dropped.
Returns
-------
dropped : Index
Raises
------
KeyError
If not all of the labels are found in the selected axis
"""
arr_dtype = "object" if self.dtype == "object" else None
labels = com.index_labels_to_array(labels, dtype=arr_dtype)
indexer = self.get_indexer(labels)
mask = indexer == -1
if mask.any():
if errors != "ignore":
raise KeyError(f"{labels[mask]} not found in axis")
indexer = indexer[~mask]
return self.delete(indexer)
# --------------------------------------------------------------------
# Generated Arithmetic, Comparison, and Unary Methods
@classmethod
def _add_comparison_methods(cls):
"""
Add in comparison methods.
"""
cls.__eq__ = _make_comparison_op(operator.eq, cls)
cls.__ne__ = _make_comparison_op(operator.ne, cls)
cls.__lt__ = _make_comparison_op(operator.lt, cls)
cls.__gt__ = _make_comparison_op(operator.gt, cls)
cls.__le__ = _make_comparison_op(operator.le, cls)
cls.__ge__ = _make_comparison_op(operator.ge, cls)
@classmethod
def _add_numeric_methods_add_sub_disabled(cls):
"""
Add in the numeric add/sub methods to disable.
"""
cls.__add__ = make_invalid_op("__add__")
cls.__radd__ = make_invalid_op("__radd__")
cls.__iadd__ = make_invalid_op("__iadd__")
cls.__sub__ = make_invalid_op("__sub__")
cls.__rsub__ = make_invalid_op("__rsub__")
cls.__isub__ = make_invalid_op("__isub__")
@classmethod
def _add_numeric_methods_disabled(cls):
"""
Add in numeric methods to disable other than add/sub.
"""
cls.__pow__ = make_invalid_op("__pow__")
cls.__rpow__ = make_invalid_op("__rpow__")
cls.__mul__ = make_invalid_op("__mul__")
cls.__rmul__ = make_invalid_op("__rmul__")
cls.__floordiv__ = make_invalid_op("__floordiv__")
cls.__rfloordiv__ = make_invalid_op("__rfloordiv__")
cls.__truediv__ = make_invalid_op("__truediv__")
cls.__rtruediv__ = make_invalid_op("__rtruediv__")
cls.__mod__ = make_invalid_op("__mod__")
cls.__divmod__ = make_invalid_op("__divmod__")
cls.__neg__ = make_invalid_op("__neg__")
cls.__pos__ = make_invalid_op("__pos__")
cls.__abs__ = make_invalid_op("__abs__")
cls.__inv__ = make_invalid_op("__inv__")
@classmethod
def _add_numeric_methods_binary(cls):
"""
Add in numeric methods.
"""
cls.__add__ = _make_arithmetic_op(operator.add, cls)
cls.__radd__ = _make_arithmetic_op(ops.radd, cls)
cls.__sub__ = _make_arithmetic_op(operator.sub, cls)
cls.__rsub__ = _make_arithmetic_op(ops.rsub, cls)
cls.__rpow__ = _make_arithmetic_op(ops.rpow, cls)
cls.__pow__ = _make_arithmetic_op(operator.pow, cls)
cls.__truediv__ = _make_arithmetic_op(operator.truediv, cls)
cls.__rtruediv__ = _make_arithmetic_op(ops.rtruediv, cls)
# TODO: rmod? rdivmod?
cls.__mod__ = _make_arithmetic_op(operator.mod, cls)
cls.__floordiv__ = _make_arithmetic_op(operator.floordiv, cls)
cls.__rfloordiv__ = _make_arithmetic_op(ops.rfloordiv, cls)
cls.__divmod__ = _make_arithmetic_op(divmod, cls)
cls.__mul__ = _make_arithmetic_op(operator.mul, cls)
cls.__rmul__ = _make_arithmetic_op(ops.rmul, cls)
@classmethod
def _add_numeric_methods_unary(cls):
"""
Add in numeric unary methods.
"""
def _make_evaluate_unary(op, opstr):
def _evaluate_numeric_unary(self):
attrs = self._get_attributes_dict()
return Index(op(self.values), **attrs)
_evaluate_numeric_unary.__name__ = opstr
return _evaluate_numeric_unary
cls.__neg__ = _make_evaluate_unary(operator.neg, "__neg__")
cls.__pos__ = _make_evaluate_unary(operator.pos, "__pos__")
cls.__abs__ = _make_evaluate_unary(np.abs, "__abs__")
cls.__inv__ = _make_evaluate_unary(lambda x: -x, "__inv__")
@classmethod
def _add_numeric_methods(cls):
cls._add_numeric_methods_unary()
cls._add_numeric_methods_binary()
@classmethod
def _add_logical_methods(cls):
"""
Add in logical methods.
"""
_doc = """
%(desc)s
Parameters
----------
*args
These parameters will be passed to numpy.%(outname)s.
**kwargs
These parameters will be passed to numpy.%(outname)s.
Returns
-------
%(outname)s : bool or array_like (if axis is specified)
A single element array_like may be converted to bool."""
_index_shared_docs["index_all"] = dedent(
"""
See Also
--------
Index.any : Return whether any element in an Index is True.
Series.any : Return whether any element in a Series is True.
Series.all : Return whether all elements in a Series are True.
Notes
-----
Not a Number (NaN), positive infinity and negative infinity
evaluate to True because these are not equal to zero.
Examples
--------
**all**
True, because nonzero integers are considered True.
>>> pd.Index([1, 2, 3]).all()
True
False, because ``0`` is considered False.
>>> pd.Index([0, 1, 2]).all()
False
**any**
True, because ``1`` is considered True.
>>> pd.Index([0, 0, 1]).any()
True
False, because ``0`` is considered False.
>>> pd.Index([0, 0, 0]).any()
False
"""
)
_index_shared_docs["index_any"] = dedent(
"""
See Also
--------
Index.all : Return whether all elements are True.
Series.all : Return whether all elements are True.
Notes
-----
Not a Number (NaN), positive infinity and negative infinity
evaluate to True because these are not equal to zero.
Examples
--------
>>> index = pd.Index([0, 1, 2])
>>> index.any()
True
>>> index = pd.Index([0, 0, 0])
>>> index.any()
False
"""
)
def _make_logical_function(name, desc, f):
@Substitution(outname=name, desc=desc)
@Appender(_index_shared_docs["index_" + name])
@Appender(_doc)
def logical_func(self, *args, **kwargs):
result = f(self.values)
if (
isinstance(result, (np.ndarray, ABCSeries, Index))
and result.ndim == 0
):
# return NumPy type
return result.dtype.type(result.item())
else: # pragma: no cover
return result
logical_func.__name__ = name
return logical_func
cls.all = _make_logical_function(
"all", "Return whether all elements are True.", np.all
)
cls.any = _make_logical_function(
"any", "Return whether any element is True.", np.any
)
@classmethod
def _add_logical_methods_disabled(cls):
"""
Add in logical methods to disable.
"""
cls.all = make_invalid_op("all")
cls.any = make_invalid_op("any")
@property
def shape(self):
"""
Return a tuple of the shape of the underlying data.
"""
# not using "(len(self), )" to return "correct" shape if the values
# consists of a >1 D array (see GH-27775)
# overridden in MultiIndex.shape to avoid materializing the values
return self._values.shape
Index._add_numeric_methods_disabled()
Index._add_logical_methods()
Index._add_comparison_methods()
def ensure_index_from_sequences(sequences, names=None):
"""
Construct an index from sequences of data.
A single sequence returns an Index. Many sequences returns a
MultiIndex.
Parameters
----------
sequences : sequence of sequences
names : sequence of str
Returns
-------
index : Index or MultiIndex
Examples
--------
>>> ensure_index_from_sequences([[1, 2, 3]], names=['name'])
Int64Index([1, 2, 3], dtype='int64', name='name')
>>> ensure_index_from_sequences([['a', 'a'], ['a', 'b']],
names=['L1', 'L2'])
MultiIndex([('a', 'a'),
('a', 'b')],
names=['L1', 'L2'])
See Also
--------
ensure_index
"""
from .multi import MultiIndex
if len(sequences) == 1:
if names is not None:
names = names[0]
return Index(sequences[0], name=names)
else:
return MultiIndex.from_arrays(sequences, names=names)
def ensure_index(index_like, copy=False):
"""
Ensure that we have an index from some index-like object.
Parameters
----------
index : sequence
An Index or other sequence
copy : bool
Returns
-------
index : Index or MultiIndex
Examples
--------
>>> ensure_index(['a', 'b'])
Index(['a', 'b'], dtype='object')
>>> ensure_index([('a', 'a'), ('b', 'c')])
Index([('a', 'a'), ('b', 'c')], dtype='object')
>>> ensure_index([['a', 'a'], ['b', 'c']])
MultiIndex([('a', 'b'),
('a', 'c')],
dtype='object')
)
See Also
--------
ensure_index_from_sequences
"""
if isinstance(index_like, Index):
if copy:
index_like = index_like.copy()
return index_like
if hasattr(index_like, "name"):
return Index(index_like, name=index_like.name, copy=copy)
if is_iterator(index_like):
index_like = list(index_like)
# must check for exactly list here because of strict type
# check in clean_index_list
if isinstance(index_like, list):
if type(index_like) != list:
index_like = list(index_like)
converted, all_arrays = lib.clean_index_list(index_like)
if len(converted) > 0 and all_arrays:
from .multi import MultiIndex
return MultiIndex.from_arrays(converted)
else:
index_like = converted
else:
# clean_index_list does the equivalent of copying
# so only need to do this if not list instance
if copy:
from copy import copy
index_like = copy(index_like)
return Index(index_like)
def _ensure_has_len(seq):
"""
If seq is an iterator, put its values into a list.
"""
try:
len(seq)
except TypeError:
return list(seq)
else:
return seq
def _trim_front(strings):
"""
Trims zeros and decimal points.
"""
trimmed = strings
while len(strings) > 0 and all(x[0] == " " for x in trimmed):
trimmed = [x[1:] for x in trimmed]
return trimmed
def _validate_join_method(method):
if method not in ["left", "right", "inner", "outer"]:
raise ValueError(f"do not recognize join method {method}")
def default_index(n):
from pandas.core.index import RangeIndex
return RangeIndex(0, n, name=None)
| BugsInPy/BugsInPy/temp/projects/pandas/bug-110-fixed/pandas/pandas/core/indexes/base.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-110-buggy/pandas/pandas/core/indexes/base.py |
pandas-bug-71 | """
Quantilization functions and related stuff
"""
import numpy as np
from pandas._libs import Timedelta, Timestamp
from pandas._libs.lib import infer_dtype
from pandas.core.dtypes.common import (
_NS_DTYPE,
ensure_int64,
is_bool_dtype,
is_categorical_dtype,
is_datetime64_dtype,
is_datetime64tz_dtype,
is_datetime_or_timedelta_dtype,
is_integer,
is_list_like,
is_scalar,
is_timedelta64_dtype,
)
from pandas.core.dtypes.generic import ABCSeries
from pandas.core.dtypes.missing import isna
from pandas import Categorical, Index, IntervalIndex, to_datetime, to_timedelta
import pandas.core.algorithms as algos
import pandas.core.nanops as nanops
def cut(
x,
bins,
right: bool = True,
labels=None,
retbins: bool = False,
precision: int = 3,
include_lowest: bool = False,
duplicates: str = "raise",
):
"""
Bin values into discrete intervals.
Use `cut` when you need to segment and sort data values into bins. This
function is also useful for going from a continuous variable to a
categorical variable. For example, `cut` could convert ages to groups of
age ranges. Supports binning into an equal number of bins, or a
pre-specified array of bins.
Parameters
----------
x : array-like
The input array to be binned. Must be 1-dimensional.
bins : int, sequence of scalars, or IntervalIndex
The criteria to bin by.
* int : Defines the number of equal-width bins in the range of `x`. The
range of `x` is extended by .1% on each side to include the minimum
and maximum values of `x`.
* sequence of scalars : Defines the bin edges allowing for non-uniform
width. No extension of the range of `x` is done.
* IntervalIndex : Defines the exact bins to be used. Note that
IntervalIndex for `bins` must be non-overlapping.
right : bool, default True
Indicates whether `bins` includes the rightmost edge or not. If
``right == True`` (the default), then the `bins` ``[1, 2, 3, 4]``
indicate (1,2], (2,3], (3,4]. This argument is ignored when
`bins` is an IntervalIndex.
labels : array or False, default None
Specifies the labels for the returned bins. Must be the same length as
the resulting bins. If False, returns only integer indicators of the
bins. This affects the type of the output container (see below).
This argument is ignored when `bins` is an IntervalIndex. If True,
raises an error.
retbins : bool, default False
Whether to return the bins or not. Useful when bins is provided
as a scalar.
precision : int, default 3
The precision at which to store and display the bins labels.
include_lowest : bool, default False
Whether the first interval should be left-inclusive or not.
duplicates : {default 'raise', 'drop'}, optional
If bin edges are not unique, raise ValueError or drop non-uniques.
.. versionadded:: 0.23.0
Returns
-------
out : Categorical, Series, or ndarray
An array-like object representing the respective bin for each value
of `x`. The type depends on the value of `labels`.
* True (default) : returns a Series for Series `x` or a
Categorical for all other inputs. The values stored within
are Interval dtype.
* sequence of scalars : returns a Series for Series `x` or a
Categorical for all other inputs. The values stored within
are whatever the type in the sequence is.
* False : returns an ndarray of integers.
bins : numpy.ndarray or IntervalIndex.
The computed or specified bins. Only returned when `retbins=True`.
For scalar or sequence `bins`, this is an ndarray with the computed
bins. If set `duplicates=drop`, `bins` will drop non-unique bin. For
an IntervalIndex `bins`, this is equal to `bins`.
See Also
--------
qcut : Discretize variable into equal-sized buckets based on rank
or based on sample quantiles.
Categorical : Array type for storing data that come from a
fixed set of values.
Series : One-dimensional array with axis labels (including time series).
IntervalIndex : Immutable Index implementing an ordered, sliceable set.
Notes
-----
Any NA values will be NA in the result. Out of bounds values will be NA in
the resulting Series or Categorical object.
Examples
--------
Discretize into three equal-sized bins.
>>> pd.cut(np.array([1, 7, 5, 4, 6, 3]), 3)
... # doctest: +ELLIPSIS
[(0.994, 3.0], (5.0, 7.0], (3.0, 5.0], (3.0, 5.0], (5.0, 7.0], ...
Categories (3, interval[float64]): [(0.994, 3.0] < (3.0, 5.0] ...
>>> pd.cut(np.array([1, 7, 5, 4, 6, 3]), 3, retbins=True)
... # doctest: +ELLIPSIS
([(0.994, 3.0], (5.0, 7.0], (3.0, 5.0], (3.0, 5.0], (5.0, 7.0], ...
Categories (3, interval[float64]): [(0.994, 3.0] < (3.0, 5.0] ...
array([0.994, 3. , 5. , 7. ]))
Discovers the same bins, but assign them specific labels. Notice that
the returned Categorical's categories are `labels` and is ordered.
>>> pd.cut(np.array([1, 7, 5, 4, 6, 3]),
... 3, labels=["bad", "medium", "good"])
[bad, good, medium, medium, good, bad]
Categories (3, object): [bad < medium < good]
``labels=False`` implies you just want the bins back.
>>> pd.cut([0, 1, 1, 2], bins=4, labels=False)
array([0, 1, 1, 3])
Passing a Series as an input returns a Series with categorical dtype:
>>> s = pd.Series(np.array([2, 4, 6, 8, 10]),
... index=['a', 'b', 'c', 'd', 'e'])
>>> pd.cut(s, 3)
... # doctest: +ELLIPSIS
a (1.992, 4.667]
b (1.992, 4.667]
c (4.667, 7.333]
d (7.333, 10.0]
e (7.333, 10.0]
dtype: category
Categories (3, interval[float64]): [(1.992, 4.667] < (4.667, ...
Passing a Series as an input returns a Series with mapping value.
It is used to map numerically to intervals based on bins.
>>> s = pd.Series(np.array([2, 4, 6, 8, 10]),
... index=['a', 'b', 'c', 'd', 'e'])
>>> pd.cut(s, [0, 2, 4, 6, 8, 10], labels=False, retbins=True, right=False)
... # doctest: +ELLIPSIS
(a 0.0
b 1.0
c 2.0
d 3.0
e 4.0
dtype: float64, array([0, 2, 4, 6, 8]))
Use `drop` optional when bins is not unique
>>> pd.cut(s, [0, 2, 4, 6, 10, 10], labels=False, retbins=True,
... right=False, duplicates='drop')
... # doctest: +ELLIPSIS
(a 0.0
b 1.0
c 2.0
d 3.0
e 3.0
dtype: float64, array([0, 2, 4, 6, 8]))
Passing an IntervalIndex for `bins` results in those categories exactly.
Notice that values not covered by the IntervalIndex are set to NaN. 0
is to the left of the first bin (which is closed on the right), and 1.5
falls between two bins.
>>> bins = pd.IntervalIndex.from_tuples([(0, 1), (2, 3), (4, 5)])
>>> pd.cut([0, 0.5, 1.5, 2.5, 4.5], bins)
[NaN, (0, 1], NaN, (2, 3], (4, 5]]
Categories (3, interval[int64]): [(0, 1] < (2, 3] < (4, 5]]
"""
# NOTE: this binning code is changed a bit from histogram for var(x) == 0
# for handling the cut for datetime and timedelta objects
original = x
x = _preprocess_for_cut(x)
x, dtype = _coerce_to_type(x)
if not np.iterable(bins):
if is_scalar(bins) and bins < 1:
raise ValueError("`bins` should be a positive integer.")
try: # for array-like
sz = x.size
except AttributeError:
x = np.asarray(x)
sz = x.size
if sz == 0:
raise ValueError("Cannot cut empty array")
rng = (nanops.nanmin(x), nanops.nanmax(x))
mn, mx = [mi + 0.0 for mi in rng]
if np.isinf(mn) or np.isinf(mx):
# GH 24314
raise ValueError(
"cannot specify integer `bins` when input data contains infinity"
)
elif mn == mx: # adjust end points before binning
mn -= 0.001 * abs(mn) if mn != 0 else 0.001
mx += 0.001 * abs(mx) if mx != 0 else 0.001
bins = np.linspace(mn, mx, bins + 1, endpoint=True)
else: # adjust end points after binning
bins = np.linspace(mn, mx, bins + 1, endpoint=True)
adj = (mx - mn) * 0.001 # 0.1% of the range
if right:
bins[0] -= adj
else:
bins[-1] += adj
elif isinstance(bins, IntervalIndex):
if bins.is_overlapping:
raise ValueError("Overlapping IntervalIndex is not accepted.")
else:
if is_datetime64tz_dtype(bins):
bins = np.asarray(bins, dtype=_NS_DTYPE)
else:
bins = np.asarray(bins)
bins = _convert_bin_to_numeric_type(bins, dtype)
# GH 26045: cast to float64 to avoid an overflow
if (np.diff(bins.astype("float64")) < 0).any():
raise ValueError("bins must increase monotonically.")
fac, bins = _bins_to_cuts(
x,
bins,
right=right,
labels=labels,
precision=precision,
include_lowest=include_lowest,
dtype=dtype,
duplicates=duplicates,
)
return _postprocess_for_cut(fac, bins, retbins, dtype, original)
def qcut(
x,
q,
labels=None,
retbins: bool = False,
precision: int = 3,
duplicates: str = "raise",
):
"""
Quantile-based discretization function.
Discretize variable into equal-sized buckets based on rank or based
on sample quantiles. For example 1000 values for 10 quantiles would
produce a Categorical object indicating quantile membership for each data point.
Parameters
----------
x : 1d ndarray or Series
q : int or list-like of int
Number of quantiles. 10 for deciles, 4 for quartiles, etc. Alternately
array of quantiles, e.g. [0, .25, .5, .75, 1.] for quartiles.
labels : array or False, default None
Used as labels for the resulting bins. Must be of the same length as
the resulting bins. If False, return only integer indicators of the
bins. If True, raises an error.
retbins : bool, optional
Whether to return the (bins, labels) or not. Can be useful if bins
is given as a scalar.
precision : int, optional
The precision at which to store and display the bins labels.
duplicates : {default 'raise', 'drop'}, optional
If bin edges are not unique, raise ValueError or drop non-uniques.
Returns
-------
out : Categorical or Series or array of integers if labels is False
The return type (Categorical or Series) depends on the input: a Series
of type category if input is a Series else Categorical. Bins are
represented as categories when categorical data is returned.
bins : ndarray of floats
Returned only if `retbins` is True.
Notes
-----
Out of bounds values will be NA in the resulting Categorical object
Examples
--------
>>> pd.qcut(range(5), 4)
... # doctest: +ELLIPSIS
[(-0.001, 1.0], (-0.001, 1.0], (1.0, 2.0], (2.0, 3.0], (3.0, 4.0]]
Categories (4, interval[float64]): [(-0.001, 1.0] < (1.0, 2.0] ...
>>> pd.qcut(range(5), 3, labels=["good", "medium", "bad"])
... # doctest: +SKIP
[good, good, medium, bad, bad]
Categories (3, object): [good < medium < bad]
>>> pd.qcut(range(5), 4, labels=False)
array([0, 0, 1, 2, 3])
"""
original = x
x = _preprocess_for_cut(x)
x, dtype = _coerce_to_type(x)
if is_integer(q):
quantiles = np.linspace(0, 1, q + 1)
else:
quantiles = q
bins = algos.quantile(x, quantiles)
fac, bins = _bins_to_cuts(
x,
bins,
labels=labels,
precision=precision,
include_lowest=True,
dtype=dtype,
duplicates=duplicates,
)
return _postprocess_for_cut(fac, bins, retbins, dtype, original)
def _bins_to_cuts(
x,
bins,
right: bool = True,
labels=None,
precision: int = 3,
include_lowest: bool = False,
dtype=None,
duplicates: str = "raise",
):
if duplicates not in ["raise", "drop"]:
raise ValueError(
"invalid value for 'duplicates' parameter, valid options are: raise, drop"
)
if isinstance(bins, IntervalIndex):
# we have a fast-path here
ids = bins.get_indexer(x)
result = Categorical.from_codes(ids, categories=bins, ordered=True)
return result, bins
unique_bins = algos.unique(bins)
if len(unique_bins) < len(bins) and len(bins) != 2:
if duplicates == "raise":
raise ValueError(
f"Bin edges must be unique: {repr(bins)}.\n"
f"You can drop duplicate edges by setting the 'duplicates' kwarg"
)
else:
bins = unique_bins
side = "left" if right else "right"
ids = ensure_int64(bins.searchsorted(x, side=side))
if include_lowest:
ids[x == bins[0]] = 1
na_mask = isna(x) | (ids == len(bins)) | (ids == 0)
has_nas = na_mask.any()
if labels is not False:
if not (labels is None or is_list_like(labels)):
raise ValueError(
"Bin labels must either be False, None or passed in as a "
"list-like argument"
)
elif labels is None:
labels = _format_labels(
bins, precision, right=right, include_lowest=include_lowest, dtype=dtype
)
else:
if len(labels) != len(bins) - 1:
raise ValueError(
"Bin labels must be one fewer than the number of bin edges"
)
if not is_categorical_dtype(labels):
labels = Categorical(labels, categories=labels, ordered=True)
np.putmask(ids, na_mask, 0)
result = algos.take_nd(labels, ids - 1)
else:
result = ids - 1
if has_nas:
result = result.astype(np.float64)
np.putmask(result, na_mask, np.nan)
return result, bins
def _coerce_to_type(x):
"""
if the passed data is of datetime/timedelta or bool type,
this method converts it to numeric so that cut or qcut method can
handle it
"""
dtype = None
if is_datetime64tz_dtype(x):
dtype = x.dtype
elif is_datetime64_dtype(x):
x = to_datetime(x)
dtype = np.dtype("datetime64[ns]")
elif is_timedelta64_dtype(x):
x = to_timedelta(x)
dtype = np.dtype("timedelta64[ns]")
elif is_bool_dtype(x):
# GH 20303
x = x.astype(np.int64)
if dtype is not None:
# GH 19768: force NaT to NaN during integer conversion
x = np.where(x.notna(), x.view(np.int64), np.nan)
return x, dtype
def _convert_bin_to_numeric_type(bins, dtype):
"""
if the passed bin is of datetime/timedelta type,
this method converts it to integer
Parameters
----------
bins : list-like of bins
dtype : dtype of data
Raises
------
ValueError if bins are not of a compat dtype to dtype
"""
bins_dtype = infer_dtype(bins, skipna=False)
if is_timedelta64_dtype(dtype):
if bins_dtype in ["timedelta", "timedelta64"]:
bins = to_timedelta(bins).view(np.int64)
else:
raise ValueError("bins must be of timedelta64 dtype")
elif is_datetime64_dtype(dtype) or is_datetime64tz_dtype(dtype):
if bins_dtype in ["datetime", "datetime64"]:
bins = to_datetime(bins).view(np.int64)
else:
raise ValueError("bins must be of datetime64 dtype")
return bins
def _convert_bin_to_datelike_type(bins, dtype):
"""
Convert bins to a DatetimeIndex or TimedeltaIndex if the original dtype is
datelike
Parameters
----------
bins : list-like of bins
dtype : dtype of data
Returns
-------
bins : Array-like of bins, DatetimeIndex or TimedeltaIndex if dtype is
datelike
"""
if is_datetime64tz_dtype(dtype):
bins = to_datetime(bins.astype(np.int64), utc=True).tz_convert(dtype.tz)
elif is_datetime_or_timedelta_dtype(dtype):
bins = Index(bins.astype(np.int64), dtype=dtype)
return bins
def _format_labels(
bins, precision: int, right: bool = True, include_lowest: bool = False, dtype=None
):
""" based on the dtype, return our labels """
closed = "right" if right else "left"
if is_datetime64tz_dtype(dtype):
formatter = lambda x: Timestamp(x, tz=dtype.tz)
adjust = lambda x: x - Timedelta("1ns")
elif is_datetime64_dtype(dtype):
formatter = Timestamp
adjust = lambda x: x - Timedelta("1ns")
elif is_timedelta64_dtype(dtype):
formatter = Timedelta
adjust = lambda x: x - Timedelta("1ns")
else:
precision = _infer_precision(precision, bins)
formatter = lambda x: _round_frac(x, precision)
adjust = lambda x: x - 10 ** (-precision)
breaks = [formatter(b) for b in bins]
if right and include_lowest:
# adjust lhs of first interval by precision to account for being right closed
breaks[0] = adjust(breaks[0])
return IntervalIndex.from_breaks(breaks, closed=closed)
def _preprocess_for_cut(x):
"""
handles preprocessing for cut where we convert passed
input to array, strip the index information and store it
separately
"""
# Check that the passed array is a Pandas or Numpy object
# We don't want to strip away a Pandas data-type here (e.g. datetimetz)
ndim = getattr(x, "ndim", None)
if ndim is None:
x = np.asarray(x)
if x.ndim != 1:
raise ValueError("Input array must be 1 dimensional")
return x
def _postprocess_for_cut(fac, bins, retbins: bool, dtype, original):
"""
handles post processing for the cut method where
we combine the index information if the originally passed
datatype was a series
"""
if isinstance(original, ABCSeries):
fac = original._constructor(fac, index=original.index, name=original.name)
if not retbins:
return fac
bins = _convert_bin_to_datelike_type(bins, dtype)
return fac, bins
def _round_frac(x, precision: int):
"""
Round the fractional part of the given number
"""
if not np.isfinite(x) or x == 0:
return x
else:
frac, whole = np.modf(x)
if whole == 0:
digits = -int(np.floor(np.log10(abs(frac)))) - 1 + precision
else:
digits = precision
return np.around(x, digits)
def _infer_precision(base_precision: int, bins) -> int:
"""Infer an appropriate precision for _round_frac
"""
for precision in range(base_precision, 20):
levels = [_round_frac(b, precision) for b in bins]
if algos.unique(levels).size == bins.size:
return precision
return base_precision # default
"""
Quantilization functions and related stuff
"""
import numpy as np
from pandas._libs import Timedelta, Timestamp
from pandas._libs.lib import infer_dtype
from pandas.core.dtypes.common import (
_NS_DTYPE,
ensure_int64,
is_bool_dtype,
is_categorical_dtype,
is_datetime64_dtype,
is_datetime64tz_dtype,
is_datetime_or_timedelta_dtype,
is_extension_array_dtype,
is_integer,
is_integer_dtype,
is_list_like,
is_scalar,
is_timedelta64_dtype,
)
from pandas.core.dtypes.generic import ABCSeries
from pandas.core.dtypes.missing import isna
from pandas import Categorical, Index, IntervalIndex, to_datetime, to_timedelta
import pandas.core.algorithms as algos
import pandas.core.nanops as nanops
def cut(
x,
bins,
right: bool = True,
labels=None,
retbins: bool = False,
precision: int = 3,
include_lowest: bool = False,
duplicates: str = "raise",
):
"""
Bin values into discrete intervals.
Use `cut` when you need to segment and sort data values into bins. This
function is also useful for going from a continuous variable to a
categorical variable. For example, `cut` could convert ages to groups of
age ranges. Supports binning into an equal number of bins, or a
pre-specified array of bins.
Parameters
----------
x : array-like
The input array to be binned. Must be 1-dimensional.
bins : int, sequence of scalars, or IntervalIndex
The criteria to bin by.
* int : Defines the number of equal-width bins in the range of `x`. The
range of `x` is extended by .1% on each side to include the minimum
and maximum values of `x`.
* sequence of scalars : Defines the bin edges allowing for non-uniform
width. No extension of the range of `x` is done.
* IntervalIndex : Defines the exact bins to be used. Note that
IntervalIndex for `bins` must be non-overlapping.
right : bool, default True
Indicates whether `bins` includes the rightmost edge or not. If
``right == True`` (the default), then the `bins` ``[1, 2, 3, 4]``
indicate (1,2], (2,3], (3,4]. This argument is ignored when
`bins` is an IntervalIndex.
labels : array or False, default None
Specifies the labels for the returned bins. Must be the same length as
the resulting bins. If False, returns only integer indicators of the
bins. This affects the type of the output container (see below).
This argument is ignored when `bins` is an IntervalIndex. If True,
raises an error.
retbins : bool, default False
Whether to return the bins or not. Useful when bins is provided
as a scalar.
precision : int, default 3
The precision at which to store and display the bins labels.
include_lowest : bool, default False
Whether the first interval should be left-inclusive or not.
duplicates : {default 'raise', 'drop'}, optional
If bin edges are not unique, raise ValueError or drop non-uniques.
.. versionadded:: 0.23.0
Returns
-------
out : Categorical, Series, or ndarray
An array-like object representing the respective bin for each value
of `x`. The type depends on the value of `labels`.
* True (default) : returns a Series for Series `x` or a
Categorical for all other inputs. The values stored within
are Interval dtype.
* sequence of scalars : returns a Series for Series `x` or a
Categorical for all other inputs. The values stored within
are whatever the type in the sequence is.
* False : returns an ndarray of integers.
bins : numpy.ndarray or IntervalIndex.
The computed or specified bins. Only returned when `retbins=True`.
For scalar or sequence `bins`, this is an ndarray with the computed
bins. If set `duplicates=drop`, `bins` will drop non-unique bin. For
an IntervalIndex `bins`, this is equal to `bins`.
See Also
--------
qcut : Discretize variable into equal-sized buckets based on rank
or based on sample quantiles.
Categorical : Array type for storing data that come from a
fixed set of values.
Series : One-dimensional array with axis labels (including time series).
IntervalIndex : Immutable Index implementing an ordered, sliceable set.
Notes
-----
Any NA values will be NA in the result. Out of bounds values will be NA in
the resulting Series or Categorical object.
Examples
--------
Discretize into three equal-sized bins.
>>> pd.cut(np.array([1, 7, 5, 4, 6, 3]), 3)
... # doctest: +ELLIPSIS
[(0.994, 3.0], (5.0, 7.0], (3.0, 5.0], (3.0, 5.0], (5.0, 7.0], ...
Categories (3, interval[float64]): [(0.994, 3.0] < (3.0, 5.0] ...
>>> pd.cut(np.array([1, 7, 5, 4, 6, 3]), 3, retbins=True)
... # doctest: +ELLIPSIS
([(0.994, 3.0], (5.0, 7.0], (3.0, 5.0], (3.0, 5.0], (5.0, 7.0], ...
Categories (3, interval[float64]): [(0.994, 3.0] < (3.0, 5.0] ...
array([0.994, 3. , 5. , 7. ]))
Discovers the same bins, but assign them specific labels. Notice that
the returned Categorical's categories are `labels` and is ordered.
>>> pd.cut(np.array([1, 7, 5, 4, 6, 3]),
... 3, labels=["bad", "medium", "good"])
[bad, good, medium, medium, good, bad]
Categories (3, object): [bad < medium < good]
``labels=False`` implies you just want the bins back.
>>> pd.cut([0, 1, 1, 2], bins=4, labels=False)
array([0, 1, 1, 3])
Passing a Series as an input returns a Series with categorical dtype:
>>> s = pd.Series(np.array([2, 4, 6, 8, 10]),
... index=['a', 'b', 'c', 'd', 'e'])
>>> pd.cut(s, 3)
... # doctest: +ELLIPSIS
a (1.992, 4.667]
b (1.992, 4.667]
c (4.667, 7.333]
d (7.333, 10.0]
e (7.333, 10.0]
dtype: category
Categories (3, interval[float64]): [(1.992, 4.667] < (4.667, ...
Passing a Series as an input returns a Series with mapping value.
It is used to map numerically to intervals based on bins.
>>> s = pd.Series(np.array([2, 4, 6, 8, 10]),
... index=['a', 'b', 'c', 'd', 'e'])
>>> pd.cut(s, [0, 2, 4, 6, 8, 10], labels=False, retbins=True, right=False)
... # doctest: +ELLIPSIS
(a 0.0
b 1.0
c 2.0
d 3.0
e 4.0
dtype: float64, array([0, 2, 4, 6, 8]))
Use `drop` optional when bins is not unique
>>> pd.cut(s, [0, 2, 4, 6, 10, 10], labels=False, retbins=True,
... right=False, duplicates='drop')
... # doctest: +ELLIPSIS
(a 0.0
b 1.0
c 2.0
d 3.0
e 3.0
dtype: float64, array([0, 2, 4, 6, 8]))
Passing an IntervalIndex for `bins` results in those categories exactly.
Notice that values not covered by the IntervalIndex are set to NaN. 0
is to the left of the first bin (which is closed on the right), and 1.5
falls between two bins.
>>> bins = pd.IntervalIndex.from_tuples([(0, 1), (2, 3), (4, 5)])
>>> pd.cut([0, 0.5, 1.5, 2.5, 4.5], bins)
[NaN, (0, 1], NaN, (2, 3], (4, 5]]
Categories (3, interval[int64]): [(0, 1] < (2, 3] < (4, 5]]
"""
# NOTE: this binning code is changed a bit from histogram for var(x) == 0
# for handling the cut for datetime and timedelta objects
original = x
x = _preprocess_for_cut(x)
x, dtype = _coerce_to_type(x)
# To support cut(IntegerArray), we convert to object dtype with NaN
# Will properly support in the future.
# https://github.com/pandas-dev/pandas/pull/31290
if is_extension_array_dtype(x.dtype) and is_integer_dtype(x.dtype):
x = x.to_numpy(dtype=object, na_value=np.nan)
if not np.iterable(bins):
if is_scalar(bins) and bins < 1:
raise ValueError("`bins` should be a positive integer.")
try: # for array-like
sz = x.size
except AttributeError:
x = np.asarray(x)
sz = x.size
if sz == 0:
raise ValueError("Cannot cut empty array")
rng = (nanops.nanmin(x), nanops.nanmax(x))
mn, mx = [mi + 0.0 for mi in rng]
if np.isinf(mn) or np.isinf(mx):
# GH 24314
raise ValueError(
"cannot specify integer `bins` when input data contains infinity"
)
elif mn == mx: # adjust end points before binning
mn -= 0.001 * abs(mn) if mn != 0 else 0.001
mx += 0.001 * abs(mx) if mx != 0 else 0.001
bins = np.linspace(mn, mx, bins + 1, endpoint=True)
else: # adjust end points after binning
bins = np.linspace(mn, mx, bins + 1, endpoint=True)
adj = (mx - mn) * 0.001 # 0.1% of the range
if right:
bins[0] -= adj
else:
bins[-1] += adj
elif isinstance(bins, IntervalIndex):
if bins.is_overlapping:
raise ValueError("Overlapping IntervalIndex is not accepted.")
else:
if is_datetime64tz_dtype(bins):
bins = np.asarray(bins, dtype=_NS_DTYPE)
else:
bins = np.asarray(bins)
bins = _convert_bin_to_numeric_type(bins, dtype)
# GH 26045: cast to float64 to avoid an overflow
if (np.diff(bins.astype("float64")) < 0).any():
raise ValueError("bins must increase monotonically.")
fac, bins = _bins_to_cuts(
x,
bins,
right=right,
labels=labels,
precision=precision,
include_lowest=include_lowest,
dtype=dtype,
duplicates=duplicates,
)
return _postprocess_for_cut(fac, bins, retbins, dtype, original)
def qcut(
x,
q,
labels=None,
retbins: bool = False,
precision: int = 3,
duplicates: str = "raise",
):
"""
Quantile-based discretization function.
Discretize variable into equal-sized buckets based on rank or based
on sample quantiles. For example 1000 values for 10 quantiles would
produce a Categorical object indicating quantile membership for each data point.
Parameters
----------
x : 1d ndarray or Series
q : int or list-like of int
Number of quantiles. 10 for deciles, 4 for quartiles, etc. Alternately
array of quantiles, e.g. [0, .25, .5, .75, 1.] for quartiles.
labels : array or False, default None
Used as labels for the resulting bins. Must be of the same length as
the resulting bins. If False, return only integer indicators of the
bins. If True, raises an error.
retbins : bool, optional
Whether to return the (bins, labels) or not. Can be useful if bins
is given as a scalar.
precision : int, optional
The precision at which to store and display the bins labels.
duplicates : {default 'raise', 'drop'}, optional
If bin edges are not unique, raise ValueError or drop non-uniques.
Returns
-------
out : Categorical or Series or array of integers if labels is False
The return type (Categorical or Series) depends on the input: a Series
of type category if input is a Series else Categorical. Bins are
represented as categories when categorical data is returned.
bins : ndarray of floats
Returned only if `retbins` is True.
Notes
-----
Out of bounds values will be NA in the resulting Categorical object
Examples
--------
>>> pd.qcut(range(5), 4)
... # doctest: +ELLIPSIS
[(-0.001, 1.0], (-0.001, 1.0], (1.0, 2.0], (2.0, 3.0], (3.0, 4.0]]
Categories (4, interval[float64]): [(-0.001, 1.0] < (1.0, 2.0] ...
>>> pd.qcut(range(5), 3, labels=["good", "medium", "bad"])
... # doctest: +SKIP
[good, good, medium, bad, bad]
Categories (3, object): [good < medium < bad]
>>> pd.qcut(range(5), 4, labels=False)
array([0, 0, 1, 2, 3])
"""
original = x
x = _preprocess_for_cut(x)
x, dtype = _coerce_to_type(x)
if is_integer(q):
quantiles = np.linspace(0, 1, q + 1)
else:
quantiles = q
bins = algos.quantile(x, quantiles)
fac, bins = _bins_to_cuts(
x,
bins,
labels=labels,
precision=precision,
include_lowest=True,
dtype=dtype,
duplicates=duplicates,
)
return _postprocess_for_cut(fac, bins, retbins, dtype, original)
def _bins_to_cuts(
x,
bins,
right: bool = True,
labels=None,
precision: int = 3,
include_lowest: bool = False,
dtype=None,
duplicates: str = "raise",
):
if duplicates not in ["raise", "drop"]:
raise ValueError(
"invalid value for 'duplicates' parameter, valid options are: raise, drop"
)
if isinstance(bins, IntervalIndex):
# we have a fast-path here
ids = bins.get_indexer(x)
result = Categorical.from_codes(ids, categories=bins, ordered=True)
return result, bins
unique_bins = algos.unique(bins)
if len(unique_bins) < len(bins) and len(bins) != 2:
if duplicates == "raise":
raise ValueError(
f"Bin edges must be unique: {repr(bins)}.\n"
f"You can drop duplicate edges by setting the 'duplicates' kwarg"
)
else:
bins = unique_bins
side = "left" if right else "right"
ids = ensure_int64(bins.searchsorted(x, side=side))
if include_lowest:
ids[x == bins[0]] = 1
na_mask = isna(x) | (ids == len(bins)) | (ids == 0)
has_nas = na_mask.any()
if labels is not False:
if not (labels is None or is_list_like(labels)):
raise ValueError(
"Bin labels must either be False, None or passed in as a "
"list-like argument"
)
elif labels is None:
labels = _format_labels(
bins, precision, right=right, include_lowest=include_lowest, dtype=dtype
)
else:
if len(labels) != len(bins) - 1:
raise ValueError(
"Bin labels must be one fewer than the number of bin edges"
)
if not is_categorical_dtype(labels):
labels = Categorical(labels, categories=labels, ordered=True)
np.putmask(ids, na_mask, 0)
result = algos.take_nd(labels, ids - 1)
else:
result = ids - 1
if has_nas:
result = result.astype(np.float64)
np.putmask(result, na_mask, np.nan)
return result, bins
def _coerce_to_type(x):
"""
if the passed data is of datetime/timedelta or bool type,
this method converts it to numeric so that cut or qcut method can
handle it
"""
dtype = None
if is_datetime64tz_dtype(x):
dtype = x.dtype
elif is_datetime64_dtype(x):
x = to_datetime(x)
dtype = np.dtype("datetime64[ns]")
elif is_timedelta64_dtype(x):
x = to_timedelta(x)
dtype = np.dtype("timedelta64[ns]")
elif is_bool_dtype(x):
# GH 20303
x = x.astype(np.int64)
if dtype is not None:
# GH 19768: force NaT to NaN during integer conversion
x = np.where(x.notna(), x.view(np.int64), np.nan)
return x, dtype
def _convert_bin_to_numeric_type(bins, dtype):
"""
if the passed bin is of datetime/timedelta type,
this method converts it to integer
Parameters
----------
bins : list-like of bins
dtype : dtype of data
Raises
------
ValueError if bins are not of a compat dtype to dtype
"""
bins_dtype = infer_dtype(bins, skipna=False)
if is_timedelta64_dtype(dtype):
if bins_dtype in ["timedelta", "timedelta64"]:
bins = to_timedelta(bins).view(np.int64)
else:
raise ValueError("bins must be of timedelta64 dtype")
elif is_datetime64_dtype(dtype) or is_datetime64tz_dtype(dtype):
if bins_dtype in ["datetime", "datetime64"]:
bins = to_datetime(bins).view(np.int64)
else:
raise ValueError("bins must be of datetime64 dtype")
return bins
def _convert_bin_to_datelike_type(bins, dtype):
"""
Convert bins to a DatetimeIndex or TimedeltaIndex if the original dtype is
datelike
Parameters
----------
bins : list-like of bins
dtype : dtype of data
Returns
-------
bins : Array-like of bins, DatetimeIndex or TimedeltaIndex if dtype is
datelike
"""
if is_datetime64tz_dtype(dtype):
bins = to_datetime(bins.astype(np.int64), utc=True).tz_convert(dtype.tz)
elif is_datetime_or_timedelta_dtype(dtype):
bins = Index(bins.astype(np.int64), dtype=dtype)
return bins
def _format_labels(
bins, precision: int, right: bool = True, include_lowest: bool = False, dtype=None
):
""" based on the dtype, return our labels """
closed = "right" if right else "left"
if is_datetime64tz_dtype(dtype):
formatter = lambda x: Timestamp(x, tz=dtype.tz)
adjust = lambda x: x - Timedelta("1ns")
elif is_datetime64_dtype(dtype):
formatter = Timestamp
adjust = lambda x: x - Timedelta("1ns")
elif is_timedelta64_dtype(dtype):
formatter = Timedelta
adjust = lambda x: x - Timedelta("1ns")
else:
precision = _infer_precision(precision, bins)
formatter = lambda x: _round_frac(x, precision)
adjust = lambda x: x - 10 ** (-precision)
breaks = [formatter(b) for b in bins]
if right and include_lowest:
# adjust lhs of first interval by precision to account for being right closed
breaks[0] = adjust(breaks[0])
return IntervalIndex.from_breaks(breaks, closed=closed)
def _preprocess_for_cut(x):
"""
handles preprocessing for cut where we convert passed
input to array, strip the index information and store it
separately
"""
# Check that the passed array is a Pandas or Numpy object
# We don't want to strip away a Pandas data-type here (e.g. datetimetz)
ndim = getattr(x, "ndim", None)
if ndim is None:
x = np.asarray(x)
if x.ndim != 1:
raise ValueError("Input array must be 1 dimensional")
return x
def _postprocess_for_cut(fac, bins, retbins: bool, dtype, original):
"""
handles post processing for the cut method where
we combine the index information if the originally passed
datatype was a series
"""
if isinstance(original, ABCSeries):
fac = original._constructor(fac, index=original.index, name=original.name)
if not retbins:
return fac
bins = _convert_bin_to_datelike_type(bins, dtype)
return fac, bins
def _round_frac(x, precision: int):
"""
Round the fractional part of the given number
"""
if not np.isfinite(x) or x == 0:
return x
else:
frac, whole = np.modf(x)
if whole == 0:
digits = -int(np.floor(np.log10(abs(frac)))) - 1 + precision
else:
digits = precision
return np.around(x, digits)
def _infer_precision(base_precision: int, bins) -> int:
"""Infer an appropriate precision for _round_frac
"""
for precision in range(base_precision, 20):
levels = [_round_frac(b, precision) for b in bins]
if algos.unique(levels).size == bins.size:
return precision
return base_precision # default
| BugsInPy/BugsInPy/temp/projects/pandas/bug-71-fixed/pandas/pandas/core/reshape/tile.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-71-buggy/pandas/pandas/core/reshape/tile.py |
pandas-bug-55 | import collections
from datetime import timedelta
import functools
import gc
import json
import operator
import pickle
import re
from textwrap import dedent
from typing import (
TYPE_CHECKING,
Any,
Callable,
Dict,
FrozenSet,
Hashable,
List,
Mapping,
Optional,
Sequence,
Set,
Tuple,
Type,
Union,
)
import warnings
import weakref
import numpy as np
from pandas._config import config
from pandas._libs import Timestamp, iNaT, lib
from pandas._typing import (
Axis,
Dtype,
FilePathOrBuffer,
FrameOrSeries,
JSONSerializable,
Label,
Level,
Renamer,
)
from pandas.compat import set_function_name
from pandas.compat._optional import import_optional_dependency
from pandas.compat.numpy import function as nv
from pandas.errors import AbstractMethodError
from pandas.util._decorators import (
Appender,
Substitution,
doc,
rewrite_axis_style_signature,
)
from pandas.util._validators import (
validate_bool_kwarg,
validate_fillna_kwargs,
validate_percentile,
)
from pandas.core.dtypes.common import (
ensure_int64,
ensure_object,
ensure_str,
is_bool,
is_bool_dtype,
is_datetime64_any_dtype,
is_datetime64tz_dtype,
is_dict_like,
is_extension_array_dtype,
is_float,
is_integer,
is_list_like,
is_number,
is_numeric_dtype,
is_object_dtype,
is_period_arraylike,
is_re_compilable,
is_scalar,
is_timedelta64_dtype,
pandas_dtype,
)
from pandas.core.dtypes.generic import ABCDataFrame, ABCSeries
from pandas.core.dtypes.inference import is_hashable
from pandas.core.dtypes.missing import isna, notna
import pandas as pd
from pandas.core import missing, nanops
import pandas.core.algorithms as algos
from pandas.core.base import PandasObject, SelectionMixin
import pandas.core.common as com
from pandas.core.construction import create_series_with_explicit_dtype
from pandas.core.indexes.api import (
Index,
InvalidIndexError,
MultiIndex,
RangeIndex,
ensure_index,
)
from pandas.core.indexes.datetimes import DatetimeIndex
from pandas.core.indexes.period import Period, PeriodIndex
import pandas.core.indexing as indexing
from pandas.core.internals import BlockManager
from pandas.core.missing import find_valid_index
from pandas.core.ops import _align_method_FRAME
from pandas.io.formats import format as fmt
from pandas.io.formats.format import DataFrameFormatter, format_percentiles
from pandas.io.formats.printing import pprint_thing
from pandas.tseries.frequencies import to_offset
if TYPE_CHECKING:
from pandas.core.resample import Resampler
# goal is to be able to define the docs close to function, while still being
# able to share
_shared_docs: Dict[str, str] = dict()
_shared_doc_kwargs = dict(
axes="keywords for axes",
klass="Series/DataFrame",
axes_single_arg="int or labels for object",
args_transpose="axes to permute (int or label for object)",
optional_by="""
by : str or list of str
Name or list of names to sort by""",
)
def _single_replace(self, to_replace, method, inplace, limit):
"""
Replaces values in a Series using the fill method specified when no
replacement value is given in the replace method
"""
if self.ndim != 1:
raise TypeError(
f"cannot replace {to_replace} with method {method} on a "
f"{type(self).__name__}"
)
orig_dtype = self.dtype
result = self if inplace else self.copy()
fill_f = missing.get_fill_func(method)
mask = missing.mask_missing(result.values, to_replace)
values = fill_f(result.values, limit=limit, mask=mask)
if values.dtype == orig_dtype and inplace:
return
result = pd.Series(values, index=self.index, dtype=self.dtype).__finalize__(self)
if inplace:
self._update_inplace(result._data)
return
return result
bool_t = bool # Need alias because NDFrame has def bool:
class NDFrame(PandasObject, SelectionMixin, indexing.IndexingMixin):
"""
N-dimensional analogue of DataFrame. Store multi-dimensional in a
size-mutable, labeled data structure
Parameters
----------
data : BlockManager
axes : list
copy : bool, default False
"""
_internal_names: List[str] = [
"_data",
"_cacher",
"_item_cache",
"_cache",
"_is_copy",
"_subtyp",
"_name",
"_index",
"_default_kind",
"_default_fill_value",
"_metadata",
"__array_struct__",
"__array_interface__",
]
_internal_names_set: Set[str] = set(_internal_names)
_accessors: Set[str] = set()
_deprecations: FrozenSet[str] = frozenset(["get_values"])
_metadata: List[str] = []
_is_copy = None
_data: BlockManager
_attrs: Dict[Optional[Hashable], Any]
_typ: str
# ----------------------------------------------------------------------
# Constructors
def __init__(
self,
data: BlockManager,
axes: Optional[List[Index]] = None,
copy: bool = False,
dtype: Optional[Dtype] = None,
attrs: Optional[Mapping[Optional[Hashable], Any]] = None,
fastpath: bool = False,
):
if not fastpath:
if dtype is not None:
data = data.astype(dtype)
elif copy:
data = data.copy()
if axes is not None:
for i, ax in enumerate(axes):
data = data.reindex_axis(ax, axis=i)
object.__setattr__(self, "_is_copy", None)
object.__setattr__(self, "_data", data)
object.__setattr__(self, "_item_cache", {})
if attrs is None:
attrs = {}
else:
attrs = dict(attrs)
object.__setattr__(self, "_attrs", attrs)
def _init_mgr(self, mgr, axes=None, dtype=None, copy=False):
""" passed a manager and a axes dict """
for a, axe in axes.items():
if axe is not None:
mgr = mgr.reindex_axis(
axe, axis=self._get_block_manager_axis(a), copy=False
)
# make a copy if explicitly requested
if copy:
mgr = mgr.copy()
if dtype is not None:
# avoid further copies if we can
if len(mgr.blocks) > 1 or mgr.blocks[0].values.dtype != dtype:
mgr = mgr.astype(dtype=dtype)
return mgr
# ----------------------------------------------------------------------
@property
def attrs(self) -> Dict[Optional[Hashable], Any]:
"""
Dictionary of global attributes on this object.
.. warning::
attrs is experimental and may change without warning.
"""
if self._attrs is None:
self._attrs = {}
return self._attrs
@attrs.setter
def attrs(self, value: Mapping[Optional[Hashable], Any]) -> None:
self._attrs = dict(value)
def _validate_dtype(self, dtype):
""" validate the passed dtype """
if dtype is not None:
dtype = pandas_dtype(dtype)
# a compound dtype
if dtype.kind == "V":
raise NotImplementedError(
"compound dtypes are not implemented "
f"in the {type(self).__name__} constructor"
)
return dtype
# ----------------------------------------------------------------------
# Construction
@property
def _constructor(self: FrameOrSeries) -> Type[FrameOrSeries]:
"""
Used when a manipulation result has the same dimensions as the
original.
"""
raise AbstractMethodError(self)
@property
def _constructor_sliced(self):
"""
Used when a manipulation result has one lower dimension(s) as the
original, such as DataFrame single columns slicing.
"""
raise AbstractMethodError(self)
@property
def _constructor_expanddim(self):
"""
Used when a manipulation result has one higher dimension as the
original, such as Series.to_frame()
"""
raise NotImplementedError
# ----------------------------------------------------------------------
# Axis
_AXIS_ALIASES = {"rows": 0}
_AXIS_IALIASES = {0: "rows"}
_stat_axis_number = 0
_stat_axis_name = "index"
_ix = None
_AXIS_ORDERS: List[str]
_AXIS_NUMBERS: Dict[str, int]
_AXIS_NAMES: Dict[int, str]
_AXIS_REVERSED: bool
_info_axis_number: int
_info_axis_name: str
_AXIS_LEN: int
def _construct_axes_dict(self, axes=None, **kwargs):
"""Return an axes dictionary for myself."""
d = {a: self._get_axis(a) for a in (axes or self._AXIS_ORDERS)}
d.update(kwargs)
return d
def _construct_axes_from_arguments(
self, args, kwargs, require_all: bool = False, sentinel=None
):
"""
Construct and returns axes if supplied in args/kwargs.
If require_all, raise if all axis arguments are not supplied
return a tuple of (axes, kwargs).
sentinel specifies the default parameter when an axis is not
supplied; useful to distinguish when a user explicitly passes None
in scenarios where None has special meaning.
"""
# construct the args
args = list(args)
for a in self._AXIS_ORDERS:
# look for a argument by position
if a not in kwargs:
try:
kwargs[a] = args.pop(0)
except IndexError:
if require_all:
raise TypeError("not enough/duplicate arguments specified!")
axes = {a: kwargs.pop(a, sentinel) for a in self._AXIS_ORDERS}
return axes, kwargs
@classmethod
def _get_axis_number(cls, axis):
axis = cls._AXIS_ALIASES.get(axis, axis)
if is_integer(axis):
if axis in cls._AXIS_NAMES:
return axis
else:
try:
return cls._AXIS_NUMBERS[axis]
except KeyError:
pass
raise ValueError(f"No axis named {axis} for object type {cls}")
@classmethod
def _get_axis_name(cls, axis):
axis = cls._AXIS_ALIASES.get(axis, axis)
if isinstance(axis, str):
if axis in cls._AXIS_NUMBERS:
return axis
else:
try:
return cls._AXIS_NAMES[axis]
except KeyError:
pass
raise ValueError(f"No axis named {axis} for object type {cls}")
def _get_axis(self, axis):
name = self._get_axis_name(axis)
return getattr(self, name)
@classmethod
def _get_block_manager_axis(cls, axis):
"""Map the axis to the block_manager axis."""
axis = cls._get_axis_number(axis)
if cls._AXIS_REVERSED:
m = cls._AXIS_LEN - 1
return m - axis
return axis
def _get_axis_resolvers(self, axis: str) -> Dict[str, ABCSeries]:
# index or columns
axis_index = getattr(self, axis)
d = dict()
prefix = axis[0]
for i, name in enumerate(axis_index.names):
if name is not None:
key = level = name
else:
# prefix with 'i' or 'c' depending on the input axis
# e.g., you must do ilevel_0 for the 0th level of an unnamed
# multiiindex
key = f"{prefix}level_{i}"
level = i
level_values = axis_index.get_level_values(level)
s = level_values.to_series()
s.index = axis_index
d[key] = s
# put the index/columns itself in the dict
if isinstance(axis_index, MultiIndex):
dindex = axis_index
else:
dindex = axis_index.to_series()
d[axis] = dindex
return d
def _get_index_resolvers(self) -> Dict[str, ABCSeries]:
from pandas.core.computation.parsing import clean_column_name
d: Dict[str, ABCSeries] = {}
for axis_name in self._AXIS_ORDERS:
d.update(self._get_axis_resolvers(axis_name))
return {clean_column_name(k): v for k, v in d.items() if not isinstance(k, int)}
def _get_cleaned_column_resolvers(self) -> Dict[str, ABCSeries]:
"""
Return the special character free column resolvers of a dataframe.
Column names with special characters are 'cleaned up' so that they can
be referred to by backtick quoting.
Used in :meth:`DataFrame.eval`.
"""
from pandas.core.computation.parsing import clean_column_name
if isinstance(self, ABCSeries):
return {clean_column_name(self.name): self}
return {
clean_column_name(k): v for k, v in self.items() if not isinstance(k, int)
}
@property
def _info_axis(self):
return getattr(self, self._info_axis_name)
@property
def _stat_axis(self):
return getattr(self, self._stat_axis_name)
@property
def shape(self) -> Tuple[int, ...]:
"""
Return a tuple of axis dimensions
"""
return tuple(len(self._get_axis(a)) for a in self._AXIS_ORDERS)
@property
def axes(self) -> List[Index]:
"""
Return index label(s) of the internal NDFrame
"""
# we do it this way because if we have reversed axes, then
# the block manager shows then reversed
return [self._get_axis(a) for a in self._AXIS_ORDERS]
@property
def ndim(self) -> int:
"""
Return an int representing the number of axes / array dimensions.
Return 1 if Series. Otherwise return 2 if DataFrame.
See Also
--------
ndarray.ndim : Number of array dimensions.
Examples
--------
>>> s = pd.Series({'a': 1, 'b': 2, 'c': 3})
>>> s.ndim
1
>>> df = pd.DataFrame({'col1': [1, 2], 'col2': [3, 4]})
>>> df.ndim
2
"""
return self._data.ndim
@property
def size(self):
"""
Return an int representing the number of elements in this object.
Return the number of rows if Series. Otherwise return the number of
rows times number of columns if DataFrame.
See Also
--------
ndarray.size : Number of elements in the array.
Examples
--------
>>> s = pd.Series({'a': 1, 'b': 2, 'c': 3})
>>> s.size
3
>>> df = pd.DataFrame({'col1': [1, 2], 'col2': [3, 4]})
>>> df.size
4
"""
return np.prod(self.shape)
@property
def _selected_obj(self: FrameOrSeries) -> FrameOrSeries:
""" internal compat with SelectionMixin """
return self
@property
def _obj_with_exclusions(self: FrameOrSeries) -> FrameOrSeries:
""" internal compat with SelectionMixin """
return self
def set_axis(self, labels, axis=0, inplace=False):
"""
Assign desired index to given axis.
Indexes for%(extended_summary_sub)s row labels can be changed by assigning
a list-like or Index.
.. versionchanged:: 0.21.0
The signature is now `labels` and `axis`, consistent with
the rest of pandas API. Previously, the `axis` and `labels`
arguments were respectively the first and second positional
arguments.
Parameters
----------
labels : list-like, Index
The values for the new index.
axis : %(axes_single_arg)s, default 0
The axis to update. The value 0 identifies the rows%(axis_description_sub)s.
inplace : bool, default False
Whether to return a new %(klass)s instance.
Returns
-------
renamed : %(klass)s or None
An object of type %(klass)s if inplace=False, None otherwise.
See Also
--------
%(klass)s.rename_axis : Alter the name of the index%(see_also_sub)s.
"""
if inplace:
setattr(self, self._get_axis_name(axis), labels)
else:
obj = self.copy()
obj.set_axis(labels, axis=axis, inplace=True)
return obj
def _set_axis(self, axis, labels) -> None:
self._data.set_axis(axis, labels)
self._clear_item_cache()
def swapaxes(self: FrameOrSeries, axis1, axis2, copy=True) -> FrameOrSeries:
"""
Interchange axes and swap values axes appropriately.
Returns
-------
y : same as input
"""
i = self._get_axis_number(axis1)
j = self._get_axis_number(axis2)
if i == j:
if copy:
return self.copy()
return self
mapping = {i: j, j: i}
new_axes = (self._get_axis(mapping.get(k, k)) for k in range(self._AXIS_LEN))
new_values = self.values.swapaxes(i, j)
if copy:
new_values = new_values.copy()
return self._constructor(new_values, *new_axes).__finalize__(self)
def droplevel(self: FrameOrSeries, level, axis=0) -> FrameOrSeries:
"""
Return DataFrame with requested index / column level(s) removed.
.. versionadded:: 0.24.0
Parameters
----------
level : int, str, or list-like
If a string is given, must be the name of a level
If list-like, elements must be names or positional indexes
of levels.
axis : {0 or 'index', 1 or 'columns'}, default 0
Returns
-------
DataFrame
DataFrame with requested index / column level(s) removed.
Examples
--------
>>> df = pd.DataFrame([
... [1, 2, 3, 4],
... [5, 6, 7, 8],
... [9, 10, 11, 12]
... ]).set_index([0, 1]).rename_axis(['a', 'b'])
>>> df.columns = pd.MultiIndex.from_tuples([
... ('c', 'e'), ('d', 'f')
... ], names=['level_1', 'level_2'])
>>> df
level_1 c d
level_2 e f
a b
1 2 3 4
5 6 7 8
9 10 11 12
>>> df.droplevel('a')
level_1 c d
level_2 e f
b
2 3 4
6 7 8
10 11 12
>>> df.droplevel('level2', axis=1)
level_1 c d
a b
1 2 3 4
5 6 7 8
9 10 11 12
"""
labels = self._get_axis(axis)
new_labels = labels.droplevel(level)
result = self.set_axis(new_labels, axis=axis, inplace=False)
return result
def pop(self: FrameOrSeries, item) -> FrameOrSeries:
"""
Return item and drop from frame. Raise KeyError if not found.
Parameters
----------
item : str
Label of column to be popped.
Returns
-------
Series
Examples
--------
>>> df = pd.DataFrame([('falcon', 'bird', 389.0),
... ('parrot', 'bird', 24.0),
... ('lion', 'mammal', 80.5),
... ('monkey', 'mammal', np.nan)],
... columns=('name', 'class', 'max_speed'))
>>> df
name class max_speed
0 falcon bird 389.0
1 parrot bird 24.0
2 lion mammal 80.5
3 monkey mammal NaN
>>> df.pop('class')
0 bird
1 bird
2 mammal
3 mammal
Name: class, dtype: object
>>> df
name max_speed
0 falcon 389.0
1 parrot 24.0
2 lion 80.5
3 monkey NaN
"""
result = self[item]
del self[item]
try:
result._reset_cacher()
except AttributeError:
pass
return result
def squeeze(self, axis=None):
"""
Squeeze 1 dimensional axis objects into scalars.
Series or DataFrames with a single element are squeezed to a scalar.
DataFrames with a single column or a single row are squeezed to a
Series. Otherwise the object is unchanged.
This method is most useful when you don't know if your
object is a Series or DataFrame, but you do know it has just a single
column. In that case you can safely call `squeeze` to ensure you have a
Series.
Parameters
----------
axis : {0 or 'index', 1 or 'columns', None}, default None
A specific axis to squeeze. By default, all length-1 axes are
squeezed.
Returns
-------
DataFrame, Series, or scalar
The projection after squeezing `axis` or all the axes.
See Also
--------
Series.iloc : Integer-location based indexing for selecting scalars.
DataFrame.iloc : Integer-location based indexing for selecting Series.
Series.to_frame : Inverse of DataFrame.squeeze for a
single-column DataFrame.
Examples
--------
>>> primes = pd.Series([2, 3, 5, 7])
Slicing might produce a Series with a single value:
>>> even_primes = primes[primes % 2 == 0]
>>> even_primes
0 2
dtype: int64
>>> even_primes.squeeze()
2
Squeezing objects with more than one value in every axis does nothing:
>>> odd_primes = primes[primes % 2 == 1]
>>> odd_primes
1 3
2 5
3 7
dtype: int64
>>> odd_primes.squeeze()
1 3
2 5
3 7
dtype: int64
Squeezing is even more effective when used with DataFrames.
>>> df = pd.DataFrame([[1, 2], [3, 4]], columns=['a', 'b'])
>>> df
a b
0 1 2
1 3 4
Slicing a single column will produce a DataFrame with the columns
having only one value:
>>> df_a = df[['a']]
>>> df_a
a
0 1
1 3
So the columns can be squeezed down, resulting in a Series:
>>> df_a.squeeze('columns')
0 1
1 3
Name: a, dtype: int64
Slicing a single row from a single column will produce a single
scalar DataFrame:
>>> df_0a = df.loc[df.index < 1, ['a']]
>>> df_0a
a
0 1
Squeezing the rows produces a single scalar Series:
>>> df_0a.squeeze('rows')
a 1
Name: 0, dtype: int64
Squeezing all axes will project directly into a scalar:
>>> df_0a.squeeze()
1
"""
axis = self._AXIS_NAMES if axis is None else (self._get_axis_number(axis),)
return self.iloc[
tuple(
0 if i in axis and len(a) == 1 else slice(None)
for i, a in enumerate(self.axes)
)
]
# ----------------------------------------------------------------------
# Rename
def rename(
self: FrameOrSeries,
mapper: Optional[Renamer] = None,
*,
index: Optional[Renamer] = None,
columns: Optional[Renamer] = None,
axis: Optional[Axis] = None,
copy: bool = True,
inplace: bool = False,
level: Optional[Level] = None,
errors: str = "ignore",
) -> Optional[FrameOrSeries]:
"""
Alter axes input function or functions. Function / dict values must be
unique (1-to-1). Labels not contained in a dict / Series will be left
as-is. Extra labels listed don't throw an error. Alternatively, change
``Series.name`` with a scalar value (Series only).
Parameters
----------
%(axes)s : scalar, list-like, dict-like or function, optional
Scalar or list-like will alter the ``Series.name`` attribute,
and raise on DataFrame.
dict-like or functions are transformations to apply to
that axis' values
copy : bool, default True
Also copy underlying data.
inplace : bool, default False
Whether to return a new %(klass)s. If True then value of copy is
ignored.
level : int or level name, default None
In case of a MultiIndex, only rename labels in the specified
level.
errors : {'ignore', 'raise'}, default 'ignore'
If 'raise', raise a `KeyError` when a dict-like `mapper`, `index`,
or `columns` contains labels that are not present in the Index
being transformed.
If 'ignore', existing keys will be renamed and extra keys will be
ignored.
Returns
-------
renamed : %(klass)s (new object)
Raises
------
KeyError
If any of the labels is not found in the selected axis and
"errors='raise'".
See Also
--------
NDFrame.rename_axis
Examples
--------
>>> s = pd.Series([1, 2, 3])
>>> s
0 1
1 2
2 3
dtype: int64
>>> s.rename("my_name") # scalar, changes Series.name
0 1
1 2
2 3
Name: my_name, dtype: int64
>>> s.rename(lambda x: x ** 2) # function, changes labels
0 1
1 2
4 3
dtype: int64
>>> s.rename({1: 3, 2: 5}) # mapping, changes labels
0 1
3 2
5 3
dtype: int64
Since ``DataFrame`` doesn't have a ``.name`` attribute,
only mapping-type arguments are allowed.
>>> df = pd.DataFrame({"A": [1, 2, 3], "B": [4, 5, 6]})
>>> df.rename(2)
Traceback (most recent call last):
...
TypeError: 'int' object is not callable
``DataFrame.rename`` supports two calling conventions
* ``(index=index_mapper, columns=columns_mapper, ...)``
* ``(mapper, axis={'index', 'columns'}, ...)``
We *highly* recommend using keyword arguments to clarify your
intent.
>>> df.rename(index=str, columns={"A": "a", "B": "c"})
a c
0 1 4
1 2 5
2 3 6
>>> df.rename(index=str, columns={"A": "a", "C": "c"})
a B
0 1 4
1 2 5
2 3 6
Using axis-style parameters
>>> df.rename(str.lower, axis='columns')
a b
0 1 4
1 2 5
2 3 6
>>> df.rename({1: 2, 2: 4}, axis='index')
A B
0 1 4
2 2 5
4 3 6
See the :ref:`user guide <basics.rename>` for more.
"""
if mapper is None and index is None and columns is None:
raise TypeError("must pass an index to rename")
if index is not None or columns is not None:
if axis is not None:
raise TypeError(
"Cannot specify both 'axis' and any of 'index' or 'columns'"
)
elif mapper is not None:
raise TypeError(
"Cannot specify both 'mapper' and any of 'index' or 'columns'"
)
else:
# use the mapper argument
if axis and self._get_axis_number(axis) == 1:
columns = mapper
else:
index = mapper
result = self if inplace else self.copy(deep=copy)
for axis_no, replacements in enumerate((index, columns)):
if replacements is None:
continue
ax = self._get_axis(axis_no)
baxis = self._get_block_manager_axis(axis_no)
f = com.get_rename_function(replacements)
if level is not None:
level = ax._get_level_number(level)
# GH 13473
if not callable(replacements):
indexer = ax.get_indexer_for(replacements)
if errors == "raise" and len(indexer[indexer == -1]):
missing_labels = [
label
for index, label in enumerate(replacements)
if indexer[index] == -1
]
raise KeyError(f"{missing_labels} not found in axis")
result._data = result._data.rename_axis(
f, axis=baxis, copy=copy, level=level
)
result._clear_item_cache()
if inplace:
self._update_inplace(result._data)
return None
else:
return result.__finalize__(self)
@rewrite_axis_style_signature("mapper", [("copy", True), ("inplace", False)])
def rename_axis(self, mapper=lib.no_default, **kwargs):
"""
Set the name of the axis for the index or columns.
Parameters
----------
mapper : scalar, list-like, optional
Value to set the axis name attribute.
index, columns : scalar, list-like, dict-like or function, optional
A scalar, list-like, dict-like or functions transformations to
apply to that axis' values.
Use either ``mapper`` and ``axis`` to
specify the axis to target with ``mapper``, or ``index``
and/or ``columns``.
.. versionchanged:: 0.24.0
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to rename.
copy : bool, default True
Also copy underlying data.
inplace : bool, default False
Modifies the object directly, instead of creating a new Series
or DataFrame.
Returns
-------
Series, DataFrame, or None
The same type as the caller or None if `inplace` is True.
See Also
--------
Series.rename : Alter Series index labels or name.
DataFrame.rename : Alter DataFrame index labels or name.
Index.rename : Set new names on index.
Notes
-----
``DataFrame.rename_axis`` supports two calling conventions
* ``(index=index_mapper, columns=columns_mapper, ...)``
* ``(mapper, axis={'index', 'columns'}, ...)``
The first calling convention will only modify the names of
the index and/or the names of the Index object that is the columns.
In this case, the parameter ``copy`` is ignored.
The second calling convention will modify the names of the
the corresponding index if mapper is a list or a scalar.
However, if mapper is dict-like or a function, it will use the
deprecated behavior of modifying the axis *labels*.
We *highly* recommend using keyword arguments to clarify your
intent.
Examples
--------
**Series**
>>> s = pd.Series(["dog", "cat", "monkey"])
>>> s
0 dog
1 cat
2 monkey
dtype: object
>>> s.rename_axis("animal")
animal
0 dog
1 cat
2 monkey
dtype: object
**DataFrame**
>>> df = pd.DataFrame({"num_legs": [4, 4, 2],
... "num_arms": [0, 0, 2]},
... ["dog", "cat", "monkey"])
>>> df
num_legs num_arms
dog 4 0
cat 4 0
monkey 2 2
>>> df = df.rename_axis("animal")
>>> df
num_legs num_arms
animal
dog 4 0
cat 4 0
monkey 2 2
>>> df = df.rename_axis("limbs", axis="columns")
>>> df
limbs num_legs num_arms
animal
dog 4 0
cat 4 0
monkey 2 2
**MultiIndex**
>>> df.index = pd.MultiIndex.from_product([['mammal'],
... ['dog', 'cat', 'monkey']],
... names=['type', 'name'])
>>> df
limbs num_legs num_arms
type name
mammal dog 4 0
cat 4 0
monkey 2 2
>>> df.rename_axis(index={'type': 'class'})
limbs num_legs num_arms
class name
mammal dog 4 0
cat 4 0
monkey 2 2
>>> df.rename_axis(columns=str.upper)
LIMBS num_legs num_arms
type name
mammal dog 4 0
cat 4 0
monkey 2 2
"""
axes, kwargs = self._construct_axes_from_arguments(
(), kwargs, sentinel=lib.no_default
)
copy = kwargs.pop("copy", True)
inplace = kwargs.pop("inplace", False)
axis = kwargs.pop("axis", 0)
if axis is not None:
axis = self._get_axis_number(axis)
if kwargs:
raise TypeError(
"rename_axis() got an unexpected keyword "
f'argument "{list(kwargs.keys())[0]}"'
)
inplace = validate_bool_kwarg(inplace, "inplace")
if mapper is not lib.no_default:
# Use v0.23 behavior if a scalar or list
non_mapper = is_scalar(mapper) or (
is_list_like(mapper) and not is_dict_like(mapper)
)
if non_mapper:
return self._set_axis_name(mapper, axis=axis, inplace=inplace)
else:
raise ValueError("Use `.rename` to alter labels with a mapper.")
else:
# Use new behavior. Means that index and/or columns
# is specified
result = self if inplace else self.copy(deep=copy)
for axis in range(self._AXIS_LEN):
v = axes.get(self._AXIS_NAMES[axis])
if v is lib.no_default:
continue
non_mapper = is_scalar(v) or (is_list_like(v) and not is_dict_like(v))
if non_mapper:
newnames = v
else:
f = com.get_rename_function(v)
curnames = self._get_axis(axis).names
newnames = [f(name) for name in curnames]
result._set_axis_name(newnames, axis=axis, inplace=True)
if not inplace:
return result
def _set_axis_name(self, name, axis=0, inplace=False):
"""
Set the name(s) of the axis.
Parameters
----------
name : str or list of str
Name(s) to set.
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to set the label. The value 0 or 'index' specifies index,
and the value 1 or 'columns' specifies columns.
inplace : bool, default False
If `True`, do operation inplace and return None.
.. versionadded:: 0.21.0
Returns
-------
Series, DataFrame, or None
The same type as the caller or `None` if `inplace` is `True`.
See Also
--------
DataFrame.rename : Alter the axis labels of :class:`DataFrame`.
Series.rename : Alter the index labels or set the index name
of :class:`Series`.
Index.rename : Set the name of :class:`Index` or :class:`MultiIndex`.
Examples
--------
>>> df = pd.DataFrame({"num_legs": [4, 4, 2]},
... ["dog", "cat", "monkey"])
>>> df
num_legs
dog 4
cat 4
monkey 2
>>> df._set_axis_name("animal")
num_legs
animal
dog 4
cat 4
monkey 2
>>> df.index = pd.MultiIndex.from_product(
... [["mammal"], ['dog', 'cat', 'monkey']])
>>> df._set_axis_name(["type", "name"])
legs
type name
mammal dog 4
cat 4
monkey 2
"""
axis = self._get_axis_number(axis)
idx = self._get_axis(axis).set_names(name)
inplace = validate_bool_kwarg(inplace, "inplace")
renamed = self if inplace else self.copy()
renamed.set_axis(idx, axis=axis, inplace=True)
if not inplace:
return renamed
# ----------------------------------------------------------------------
# Comparison Methods
def _indexed_same(self, other) -> bool:
return all(
self._get_axis(a).equals(other._get_axis(a)) for a in self._AXIS_ORDERS
)
def equals(self, other):
"""
Test whether two objects contain the same elements.
This function allows two Series or DataFrames to be compared against
each other to see if they have the same shape and elements. NaNs in
the same location are considered equal. The column headers do not
need to have the same type, but the elements within the columns must
be the same dtype.
Parameters
----------
other : Series or DataFrame
The other Series or DataFrame to be compared with the first.
Returns
-------
bool
True if all elements are the same in both objects, False
otherwise.
See Also
--------
Series.eq : Compare two Series objects of the same length
and return a Series where each element is True if the element
in each Series is equal, False otherwise.
DataFrame.eq : Compare two DataFrame objects of the same shape and
return a DataFrame where each element is True if the respective
element in each DataFrame is equal, False otherwise.
testing.assert_series_equal : Raises an AssertionError if left and
right are not equal. Provides an easy interface to ignore
inequality in dtypes, indexes and precision among others.
testing.assert_frame_equal : Like assert_series_equal, but targets
DataFrames.
numpy.array_equal : Return True if two arrays have the same shape
and elements, False otherwise.
Notes
-----
This function requires that the elements have the same dtype as their
respective elements in the other Series or DataFrame. However, the
column labels do not need to have the same type, as long as they are
still considered equal.
Examples
--------
>>> df = pd.DataFrame({1: [10], 2: [20]})
>>> df
1 2
0 10 20
DataFrames df and exactly_equal have the same types and values for
their elements and column labels, which will return True.
>>> exactly_equal = pd.DataFrame({1: [10], 2: [20]})
>>> exactly_equal
1 2
0 10 20
>>> df.equals(exactly_equal)
True
DataFrames df and different_column_type have the same element
types and values, but have different types for the column labels,
which will still return True.
>>> different_column_type = pd.DataFrame({1.0: [10], 2.0: [20]})
>>> different_column_type
1.0 2.0
0 10 20
>>> df.equals(different_column_type)
True
DataFrames df and different_data_type have different types for the
same values for their elements, and will return False even though
their column labels are the same values and types.
>>> different_data_type = pd.DataFrame({1: [10.0], 2: [20.0]})
>>> different_data_type
1 2
0 10.0 20.0
>>> df.equals(different_data_type)
False
"""
if not isinstance(other, self._constructor):
return False
return self._data.equals(other._data)
# -------------------------------------------------------------------------
# Unary Methods
def __neg__(self):
values = com.values_from_object(self)
if is_bool_dtype(values):
arr = operator.inv(values)
elif (
is_numeric_dtype(values)
or is_timedelta64_dtype(values)
or is_object_dtype(values)
):
arr = operator.neg(values)
else:
raise TypeError(f"Unary negative expects numeric dtype, not {values.dtype}")
return self.__array_wrap__(arr)
def __pos__(self):
values = com.values_from_object(self)
if is_bool_dtype(values) or is_period_arraylike(values):
arr = values
elif (
is_numeric_dtype(values)
or is_timedelta64_dtype(values)
or is_object_dtype(values)
):
arr = operator.pos(values)
else:
raise TypeError(f"Unary plus expects numeric dtype, not {values.dtype}")
return self.__array_wrap__(arr)
def __invert__(self):
if not self.size:
# inv fails with 0 len
return self
new_data = self._data.apply(operator.invert)
result = self._constructor(new_data).__finalize__(self)
return result
def __nonzero__(self):
raise ValueError(
f"The truth value of a {type(self).__name__} is ambiguous. "
"Use a.empty, a.bool(), a.item(), a.any() or a.all()."
)
__bool__ = __nonzero__
def bool(self):
"""
Return the bool of a single element PandasObject.
This must be a boolean scalar value, either True or False. Raise a
ValueError if the PandasObject does not have exactly 1 element, or that
element is not boolean
Returns
-------
bool
Same single boolean value converted to bool type.
"""
v = self.squeeze()
if isinstance(v, (bool, np.bool_)):
return bool(v)
elif is_scalar(v):
raise ValueError(
"bool cannot act on a non-boolean single element "
f"{type(self).__name__}"
)
self.__nonzero__()
def __abs__(self: FrameOrSeries) -> FrameOrSeries:
return self.abs()
def __round__(self: FrameOrSeries, decimals: int = 0) -> FrameOrSeries:
return self.round(decimals)
# -------------------------------------------------------------------------
# Label or Level Combination Helpers
#
# A collection of helper methods for DataFrame/Series operations that
# accept a combination of column/index labels and levels. All such
# operations should utilize/extend these methods when possible so that we
# have consistent precedence and validation logic throughout the library.
def _is_level_reference(self, key, axis=0):
"""
Test whether a key is a level reference for a given axis.
To be considered a level reference, `key` must be a string that:
- (axis=0): Matches the name of an index level and does NOT match
a column label.
- (axis=1): Matches the name of a column level and does NOT match
an index label.
Parameters
----------
key : str
Potential level name for the given axis
axis : int, default 0
Axis that levels are associated with (0 for index, 1 for columns)
Returns
-------
is_level : bool
"""
axis = self._get_axis_number(axis)
return (
key is not None
and is_hashable(key)
and key in self.axes[axis].names
and not self._is_label_reference(key, axis=axis)
)
def _is_label_reference(self, key, axis=0) -> bool_t:
"""
Test whether a key is a label reference for a given axis.
To be considered a label reference, `key` must be a string that:
- (axis=0): Matches a column label
- (axis=1): Matches an index label
Parameters
----------
key: str
Potential label name
axis: int, default 0
Axis perpendicular to the axis that labels are associated with
(0 means search for column labels, 1 means search for index labels)
Returns
-------
is_label: bool
"""
axis = self._get_axis_number(axis)
other_axes = (ax for ax in range(self._AXIS_LEN) if ax != axis)
return (
key is not None
and is_hashable(key)
and any(key in self.axes[ax] for ax in other_axes)
)
def _is_label_or_level_reference(self, key: str, axis: int = 0) -> bool_t:
"""
Test whether a key is a label or level reference for a given axis.
To be considered either a label or a level reference, `key` must be a
string that:
- (axis=0): Matches a column label or an index level
- (axis=1): Matches an index label or a column level
Parameters
----------
key: str
Potential label or level name
axis: int, default 0
Axis that levels are associated with (0 for index, 1 for columns)
Returns
-------
is_label_or_level: bool
"""
return self._is_level_reference(key, axis=axis) or self._is_label_reference(
key, axis=axis
)
def _check_label_or_level_ambiguity(self, key, axis: int = 0) -> None:
"""
Check whether `key` is ambiguous.
By ambiguous, we mean that it matches both a level of the input
`axis` and a label of the other axis.
Parameters
----------
key: str or object
Label or level name.
axis: int, default 0
Axis that levels are associated with (0 for index, 1 for columns).
Raises
------
ValueError: `key` is ambiguous
"""
axis = self._get_axis_number(axis)
other_axes = (ax for ax in range(self._AXIS_LEN) if ax != axis)
if (
key is not None
and is_hashable(key)
and key in self.axes[axis].names
and any(key in self.axes[ax] for ax in other_axes)
):
# Build an informative and grammatical warning
level_article, level_type = (
("an", "index") if axis == 0 else ("a", "column")
)
label_article, label_type = (
("a", "column") if axis == 0 else ("an", "index")
)
msg = (
f"'{key}' is both {level_article} {level_type} level and "
f"{label_article} {label_type} label, which is ambiguous."
)
raise ValueError(msg)
def _get_label_or_level_values(self, key: str, axis: int = 0) -> np.ndarray:
"""
Return a 1-D array of values associated with `key`, a label or level
from the given `axis`.
Retrieval logic:
- (axis=0): Return column values if `key` matches a column label.
Otherwise return index level values if `key` matches an index
level.
- (axis=1): Return row values if `key` matches an index label.
Otherwise return column level values if 'key' matches a column
level
Parameters
----------
key: str
Label or level name.
axis: int, default 0
Axis that levels are associated with (0 for index, 1 for columns)
Returns
-------
values: np.ndarray
Raises
------
KeyError
if `key` matches neither a label nor a level
ValueError
if `key` matches multiple labels
FutureWarning
if `key` is ambiguous. This will become an ambiguity error in a
future version
"""
axis = self._get_axis_number(axis)
other_axes = [ax for ax in range(self._AXIS_LEN) if ax != axis]
if self._is_label_reference(key, axis=axis):
self._check_label_or_level_ambiguity(key, axis=axis)
values = self.xs(key, axis=other_axes[0])._values
elif self._is_level_reference(key, axis=axis):
values = self.axes[axis].get_level_values(key)._values
else:
raise KeyError(key)
# Check for duplicates
if values.ndim > 1:
if other_axes and isinstance(self._get_axis(other_axes[0]), MultiIndex):
multi_message = (
"\n"
"For a multi-index, the label must be a "
"tuple with elements corresponding to each level."
)
else:
multi_message = ""
label_axis_name = "column" if axis == 0 else "index"
raise ValueError(
(
f"The {label_axis_name} label '{key}' "
f"is not unique.{multi_message}"
)
)
return values
def _drop_labels_or_levels(self, keys, axis: int = 0):
"""
Drop labels and/or levels for the given `axis`.
For each key in `keys`:
- (axis=0): If key matches a column label then drop the column.
Otherwise if key matches an index level then drop the level.
- (axis=1): If key matches an index label then drop the row.
Otherwise if key matches a column level then drop the level.
Parameters
----------
keys: str or list of str
labels or levels to drop
axis: int, default 0
Axis that levels are associated with (0 for index, 1 for columns)
Returns
-------
dropped: DataFrame
Raises
------
ValueError
if any `keys` match neither a label nor a level
"""
axis = self._get_axis_number(axis)
# Validate keys
keys = com.maybe_make_list(keys)
invalid_keys = [
k for k in keys if not self._is_label_or_level_reference(k, axis=axis)
]
if invalid_keys:
raise ValueError(
(
"The following keys are not valid labels or "
f"levels for axis {axis}: {invalid_keys}"
)
)
# Compute levels and labels to drop
levels_to_drop = [k for k in keys if self._is_level_reference(k, axis=axis)]
labels_to_drop = [k for k in keys if not self._is_level_reference(k, axis=axis)]
# Perform copy upfront and then use inplace operations below.
# This ensures that we always perform exactly one copy.
# ``copy`` and/or ``inplace`` options could be added in the future.
dropped = self.copy()
if axis == 0:
# Handle dropping index levels
if levels_to_drop:
dropped.reset_index(levels_to_drop, drop=True, inplace=True)
# Handle dropping columns labels
if labels_to_drop:
dropped.drop(labels_to_drop, axis=1, inplace=True)
else:
# Handle dropping column levels
if levels_to_drop:
if isinstance(dropped.columns, MultiIndex):
# Drop the specified levels from the MultiIndex
dropped.columns = dropped.columns.droplevel(levels_to_drop)
else:
# Drop the last level of Index by replacing with
# a RangeIndex
dropped.columns = RangeIndex(dropped.columns.size)
# Handle dropping index labels
if labels_to_drop:
dropped.drop(labels_to_drop, axis=0, inplace=True)
return dropped
# ----------------------------------------------------------------------
# Iteration
def __hash__(self):
raise TypeError(
f"{repr(type(self).__name__)} objects are mutable, "
f"thus they cannot be hashed"
)
def __iter__(self):
"""
Iterate over info axis.
Returns
-------
iterator
Info axis as iterator.
"""
return iter(self._info_axis)
# can we get a better explanation of this?
def keys(self):
"""
Get the 'info axis' (see Indexing for more).
This is index for Series, columns for DataFrame.
Returns
-------
Index
Info axis.
"""
return self._info_axis
def items(self):
"""
Iterate over (label, values) on info axis
This is index for Series and columns for DataFrame.
Returns
-------
Generator
"""
for h in self._info_axis:
yield h, self[h]
@Appender(items.__doc__)
def iteritems(self):
return self.items()
def __len__(self) -> int:
"""Returns length of info axis"""
return len(self._info_axis)
def __contains__(self, key) -> bool_t:
"""True if the key is in the info axis"""
return key in self._info_axis
@property
def empty(self) -> bool_t:
"""
Indicator whether DataFrame is empty.
True if DataFrame is entirely empty (no items), meaning any of the
axes are of length 0.
Returns
-------
bool
If DataFrame is empty, return True, if not return False.
See Also
--------
Series.dropna
DataFrame.dropna
Notes
-----
If DataFrame contains only NaNs, it is still not considered empty. See
the example below.
Examples
--------
An example of an actual empty DataFrame. Notice the index is empty:
>>> df_empty = pd.DataFrame({'A' : []})
>>> df_empty
Empty DataFrame
Columns: [A]
Index: []
>>> df_empty.empty
True
If we only have NaNs in our DataFrame, it is not considered empty! We
will need to drop the NaNs to make the DataFrame empty:
>>> df = pd.DataFrame({'A' : [np.nan]})
>>> df
A
0 NaN
>>> df.empty
False
>>> df.dropna().empty
True
"""
return any(len(self._get_axis(a)) == 0 for a in self._AXIS_ORDERS)
# ----------------------------------------------------------------------
# Array Interface
# This is also set in IndexOpsMixin
# GH#23114 Ensure ndarray.__op__(DataFrame) returns NotImplemented
__array_priority__ = 1000
def __array__(self, dtype=None) -> np.ndarray:
return com.values_from_object(self)
def __array_wrap__(self, result, context=None):
result = lib.item_from_zerodim(result)
if is_scalar(result):
# e.g. we get here with np.ptp(series)
# ptp also requires the item_from_zerodim
return result
d = self._construct_axes_dict(self._AXIS_ORDERS, copy=False)
return self._constructor(result, **d).__finalize__(self)
# ideally we would define this to avoid the getattr checks, but
# is slower
# @property
# def __array_interface__(self):
# """ provide numpy array interface method """
# values = self.values
# return dict(typestr=values.dtype.str,shape=values.shape,data=values)
# ----------------------------------------------------------------------
# Picklability
def __getstate__(self) -> Dict[str, Any]:
meta = {k: getattr(self, k, None) for k in self._metadata}
return dict(
_data=self._data,
_typ=self._typ,
_metadata=self._metadata,
attrs=self.attrs,
**meta,
)
def __setstate__(self, state):
if isinstance(state, BlockManager):
self._data = state
elif isinstance(state, dict):
typ = state.get("_typ")
if typ is not None:
attrs = state.get("_attrs", {})
object.__setattr__(self, "_attrs", attrs)
# set in the order of internal names
# to avoid definitional recursion
# e.g. say fill_value needing _data to be
# defined
meta = set(self._internal_names + self._metadata)
for k in list(meta):
if k in state:
v = state[k]
object.__setattr__(self, k, v)
for k, v in state.items():
if k not in meta:
object.__setattr__(self, k, v)
else:
raise NotImplementedError("Pre-0.12 pickles are no longer supported")
elif len(state) == 2:
raise NotImplementedError("Pre-0.12 pickles are no longer supported")
self._item_cache = {}
# ----------------------------------------------------------------------
# Rendering Methods
def __repr__(self) -> str:
# string representation based upon iterating over self
# (since, by definition, `PandasContainers` are iterable)
prepr = f"[{','.join(map(pprint_thing, self))}]"
return f"{type(self).__name__}({prepr})"
def _repr_latex_(self):
"""
Returns a LaTeX representation for a particular object.
Mainly for use with nbconvert (jupyter notebook conversion to pdf).
"""
if config.get_option("display.latex.repr"):
return self.to_latex()
else:
return None
def _repr_data_resource_(self):
"""
Not a real Jupyter special repr method, but we use the same
naming convention.
"""
if config.get_option("display.html.table_schema"):
data = self.head(config.get_option("display.max_rows"))
payload = json.loads(
data.to_json(orient="table"), object_pairs_hook=collections.OrderedDict
)
return payload
# ----------------------------------------------------------------------
# I/O Methods
_shared_docs[
"to_markdown"
] = """
Print %(klass)s in Markdown-friendly format.
.. versionadded:: 1.0.0
Parameters
----------
buf : str, Path or StringIO-like, optional, default None
Buffer to write to. If None, the output is returned as a string.
mode : str, optional
Mode in which file is opened.
**kwargs
These parameters will be passed to `tabulate`.
Returns
-------
str
%(klass)s in Markdown-friendly format.
"""
_shared_docs[
"to_excel"
] = """
Write %(klass)s to an Excel sheet.
To write a single %(klass)s to an Excel .xlsx file it is only necessary to
specify a target file name. To write to multiple sheets it is necessary to
create an `ExcelWriter` object with a target file name, and specify a sheet
in the file to write to.
Multiple sheets may be written to by specifying unique `sheet_name`.
With all data written to the file it is necessary to save the changes.
Note that creating an `ExcelWriter` object with a file name that already
exists will result in the contents of the existing file being erased.
Parameters
----------
excel_writer : str or ExcelWriter object
File path or existing ExcelWriter.
sheet_name : str, default 'Sheet1'
Name of sheet which will contain DataFrame.
na_rep : str, default ''
Missing data representation.
float_format : str, optional
Format string for floating point numbers. For example
``float_format="%%.2f"`` will format 0.1234 to 0.12.
columns : sequence or list of str, optional
Columns to write.
header : bool or list of str, default True
Write out the column names. If a list of string is given it is
assumed to be aliases for the column names.
index : bool, default True
Write row names (index).
index_label : str or sequence, optional
Column label for index column(s) if desired. If not specified, and
`header` and `index` are True, then the index names are used. A
sequence should be given if the DataFrame uses MultiIndex.
startrow : int, default 0
Upper left cell row to dump data frame.
startcol : int, default 0
Upper left cell column to dump data frame.
engine : str, optional
Write engine to use, 'openpyxl' or 'xlsxwriter'. You can also set this
via the options ``io.excel.xlsx.writer``, ``io.excel.xls.writer``, and
``io.excel.xlsm.writer``.
merge_cells : bool, default True
Write MultiIndex and Hierarchical Rows as merged cells.
encoding : str, optional
Encoding of the resulting excel file. Only necessary for xlwt,
other writers support unicode natively.
inf_rep : str, default 'inf'
Representation for infinity (there is no native representation for
infinity in Excel).
verbose : bool, default True
Display more information in the error logs.
freeze_panes : tuple of int (length 2), optional
Specifies the one-based bottommost row and rightmost column that
is to be frozen.
See Also
--------
to_csv : Write DataFrame to a comma-separated values (csv) file.
ExcelWriter : Class for writing DataFrame objects into excel sheets.
read_excel : Read an Excel file into a pandas DataFrame.
read_csv : Read a comma-separated values (csv) file into DataFrame.
Notes
-----
For compatibility with :meth:`~DataFrame.to_csv`,
to_excel serializes lists and dicts to strings before writing.
Once a workbook has been saved it is not possible write further data
without rewriting the whole workbook.
Examples
--------
Create, write to and save a workbook:
>>> df1 = pd.DataFrame([['a', 'b'], ['c', 'd']],
... index=['row 1', 'row 2'],
... columns=['col 1', 'col 2'])
>>> df1.to_excel("output.xlsx") # doctest: +SKIP
To specify the sheet name:
>>> df1.to_excel("output.xlsx",
... sheet_name='Sheet_name_1') # doctest: +SKIP
If you wish to write to more than one sheet in the workbook, it is
necessary to specify an ExcelWriter object:
>>> df2 = df1.copy()
>>> with pd.ExcelWriter('output.xlsx') as writer: # doctest: +SKIP
... df1.to_excel(writer, sheet_name='Sheet_name_1')
... df2.to_excel(writer, sheet_name='Sheet_name_2')
ExcelWriter can also be used to append to an existing Excel file:
>>> with pd.ExcelWriter('output.xlsx',
... mode='a') as writer: # doctest: +SKIP
... df.to_excel(writer, sheet_name='Sheet_name_3')
To set the library that is used to write the Excel file,
you can pass the `engine` keyword (the default engine is
automatically chosen depending on the file extension):
>>> df1.to_excel('output1.xlsx', engine='xlsxwriter') # doctest: +SKIP
"""
@Appender(_shared_docs["to_excel"] % dict(klass="object"))
def to_excel(
self,
excel_writer,
sheet_name="Sheet1",
na_rep="",
float_format=None,
columns=None,
header=True,
index=True,
index_label=None,
startrow=0,
startcol=0,
engine=None,
merge_cells=True,
encoding=None,
inf_rep="inf",
verbose=True,
freeze_panes=None,
) -> None:
df = self if isinstance(self, ABCDataFrame) else self.to_frame()
from pandas.io.formats.excel import ExcelFormatter
formatter = ExcelFormatter(
df,
na_rep=na_rep,
cols=columns,
header=header,
float_format=float_format,
index=index,
index_label=index_label,
merge_cells=merge_cells,
inf_rep=inf_rep,
)
formatter.write(
excel_writer,
sheet_name=sheet_name,
startrow=startrow,
startcol=startcol,
freeze_panes=freeze_panes,
engine=engine,
)
def to_json(
self,
path_or_buf: Optional[FilePathOrBuffer] = None,
orient: Optional[str] = None,
date_format: Optional[str] = None,
double_precision: int = 10,
force_ascii: bool_t = True,
date_unit: str = "ms",
default_handler: Optional[Callable[[Any], JSONSerializable]] = None,
lines: bool_t = False,
compression: Optional[str] = "infer",
index: bool_t = True,
indent: Optional[int] = None,
) -> Optional[str]:
"""
Convert the object to a JSON string.
Note NaN's and None will be converted to null and datetime objects
will be converted to UNIX timestamps.
Parameters
----------
path_or_buf : str or file handle, optional
File path or object. If not specified, the result is returned as
a string.
orient : str
Indication of expected JSON string format.
* Series:
- default is 'index'
- allowed values are: {'split','records','index','table'}.
* DataFrame:
- default is 'columns'
- allowed values are: {'split', 'records', 'index', 'columns',
'values', 'table'}.
* The format of the JSON string:
- 'split' : dict like {'index' -> [index], 'columns' -> [columns],
'data' -> [values]}
- 'records' : list like [{column -> value}, ... , {column -> value}]
- 'index' : dict like {index -> {column -> value}}
- 'columns' : dict like {column -> {index -> value}}
- 'values' : just the values array
- 'table' : dict like {'schema': {schema}, 'data': {data}}
Describing the data, where data component is like ``orient='records'``.
.. versionchanged:: 0.20.0
date_format : {None, 'epoch', 'iso'}
Type of date conversion. 'epoch' = epoch milliseconds,
'iso' = ISO8601. The default depends on the `orient`. For
``orient='table'``, the default is 'iso'. For all other orients,
the default is 'epoch'.
double_precision : int, default 10
The number of decimal places to use when encoding
floating point values.
force_ascii : bool, default True
Force encoded string to be ASCII.
date_unit : str, default 'ms' (milliseconds)
The time unit to encode to, governs timestamp and ISO8601
precision. One of 's', 'ms', 'us', 'ns' for second, millisecond,
microsecond, and nanosecond respectively.
default_handler : callable, default None
Handler to call if object cannot otherwise be converted to a
suitable format for JSON. Should receive a single argument which is
the object to convert and return a serialisable object.
lines : bool, default False
If 'orient' is 'records' write out line delimited json format. Will
throw ValueError if incorrect 'orient' since others are not list
like.
compression : {'infer', 'gzip', 'bz2', 'zip', 'xz', None}
A string representing the compression to use in the output file,
only used when the first argument is a filename. By default, the
compression is inferred from the filename.
.. versionadded:: 0.21.0
.. versionchanged:: 0.24.0
'infer' option added and set to default
index : bool, default True
Whether to include the index values in the JSON string. Not
including the index (``index=False``) is only supported when
orient is 'split' or 'table'.
.. versionadded:: 0.23.0
indent : int, optional
Length of whitespace used to indent each record.
.. versionadded:: 1.0.0
Returns
-------
None or str
If path_or_buf is None, returns the resulting json format as a
string. Otherwise returns None.
See Also
--------
read_json
Notes
-----
The behavior of ``indent=0`` varies from the stdlib, which does not
indent the output but does insert newlines. Currently, ``indent=0``
and the default ``indent=None`` are equivalent in pandas, though this
may change in a future release.
Examples
--------
>>> df = pd.DataFrame([['a', 'b'], ['c', 'd']],
... index=['row 1', 'row 2'],
... columns=['col 1', 'col 2'])
>>> df.to_json(orient='split')
'{"columns":["col 1","col 2"],
"index":["row 1","row 2"],
"data":[["a","b"],["c","d"]]}'
Encoding/decoding a Dataframe using ``'records'`` formatted JSON.
Note that index labels are not preserved with this encoding.
>>> df.to_json(orient='records')
'[{"col 1":"a","col 2":"b"},{"col 1":"c","col 2":"d"}]'
Encoding/decoding a Dataframe using ``'index'`` formatted JSON:
>>> df.to_json(orient='index')
'{"row 1":{"col 1":"a","col 2":"b"},"row 2":{"col 1":"c","col 2":"d"}}'
Encoding/decoding a Dataframe using ``'columns'`` formatted JSON:
>>> df.to_json(orient='columns')
'{"col 1":{"row 1":"a","row 2":"c"},"col 2":{"row 1":"b","row 2":"d"}}'
Encoding/decoding a Dataframe using ``'values'`` formatted JSON:
>>> df.to_json(orient='values')
'[["a","b"],["c","d"]]'
Encoding with Table Schema
>>> df.to_json(orient='table')
'{"schema": {"fields": [{"name": "index", "type": "string"},
{"name": "col 1", "type": "string"},
{"name": "col 2", "type": "string"}],
"primaryKey": "index",
"pandas_version": "0.20.0"},
"data": [{"index": "row 1", "col 1": "a", "col 2": "b"},
{"index": "row 2", "col 1": "c", "col 2": "d"}]}'
"""
from pandas.io import json
if date_format is None and orient == "table":
date_format = "iso"
elif date_format is None:
date_format = "epoch"
config.is_nonnegative_int(indent)
indent = indent or 0
return json.to_json(
path_or_buf=path_or_buf,
obj=self,
orient=orient,
date_format=date_format,
double_precision=double_precision,
force_ascii=force_ascii,
date_unit=date_unit,
default_handler=default_handler,
lines=lines,
compression=compression,
index=index,
indent=indent,
)
def to_hdf(
self,
path_or_buf,
key: str,
mode: str = "a",
complevel: Optional[int] = None,
complib: Optional[str] = None,
append: bool_t = False,
format: Optional[str] = None,
index: bool_t = True,
min_itemsize: Optional[Union[int, Dict[str, int]]] = None,
nan_rep=None,
dropna: Optional[bool_t] = None,
data_columns: Optional[List[str]] = None,
errors: str = "strict",
encoding: str = "UTF-8",
) -> None:
"""
Write the contained data to an HDF5 file using HDFStore.
Hierarchical Data Format (HDF) is self-describing, allowing an
application to interpret the structure and contents of a file with
no outside information. One HDF file can hold a mix of related objects
which can be accessed as a group or as individual objects.
In order to add another DataFrame or Series to an existing HDF file
please use append mode and a different a key.
For more information see the :ref:`user guide <io.hdf5>`.
Parameters
----------
path_or_buf : str or pandas.HDFStore
File path or HDFStore object.
key : str
Identifier for the group in the store.
mode : {'a', 'w', 'r+'}, default 'a'
Mode to open file:
- 'w': write, a new file is created (an existing file with
the same name would be deleted).
- 'a': append, an existing file is opened for reading and
writing, and if the file does not exist it is created.
- 'r+': similar to 'a', but the file must already exist.
complevel : {0-9}, optional
Specifies a compression level for data.
A value of 0 disables compression.
complib : {'zlib', 'lzo', 'bzip2', 'blosc'}, default 'zlib'
Specifies the compression library to be used.
As of v0.20.2 these additional compressors for Blosc are supported
(default if no compressor specified: 'blosc:blosclz'):
{'blosc:blosclz', 'blosc:lz4', 'blosc:lz4hc', 'blosc:snappy',
'blosc:zlib', 'blosc:zstd'}.
Specifying a compression library which is not available issues
a ValueError.
append : bool, default False
For Table formats, append the input data to the existing.
format : {'fixed', 'table', None}, default 'fixed'
Possible values:
- 'fixed': Fixed format. Fast writing/reading. Not-appendable,
nor searchable.
- 'table': Table format. Write as a PyTables Table structure
which may perform worse but allow more flexible operations
like searching / selecting subsets of the data.
- If None, pd.get_option('io.hdf.default_format') is checked,
followed by fallback to "fixed"
errors : str, default 'strict'
Specifies how encoding and decoding errors are to be handled.
See the errors argument for :func:`open` for a full list
of options.
encoding : str, default "UTF-8"
min_itemsize : dict or int, optional
Map column names to minimum string sizes for columns.
nan_rep : Any, optional
How to represent null values as str.
Not allowed with append=True.
data_columns : list of columns or True, optional
List of columns to create as indexed data columns for on-disk
queries, or True to use all columns. By default only the axes
of the object are indexed. See :ref:`io.hdf5-query-data-columns`.
Applicable only to format='table'.
See Also
--------
DataFrame.read_hdf : Read from HDF file.
DataFrame.to_parquet : Write a DataFrame to the binary parquet format.
DataFrame.to_sql : Write to a sql table.
DataFrame.to_feather : Write out feather-format for DataFrames.
DataFrame.to_csv : Write out to a csv file.
Examples
--------
>>> df = pd.DataFrame({'A': [1, 2, 3], 'B': [4, 5, 6]},
... index=['a', 'b', 'c'])
>>> df.to_hdf('data.h5', key='df', mode='w')
We can add another object to the same file:
>>> s = pd.Series([1, 2, 3, 4])
>>> s.to_hdf('data.h5', key='s')
Reading from HDF file:
>>> pd.read_hdf('data.h5', 'df')
A B
a 1 4
b 2 5
c 3 6
>>> pd.read_hdf('data.h5', 's')
0 1
1 2
2 3
3 4
dtype: int64
Deleting file with data:
>>> import os
>>> os.remove('data.h5')
"""
from pandas.io import pytables
pytables.to_hdf(
path_or_buf,
key,
self,
mode=mode,
complevel=complevel,
complib=complib,
append=append,
format=format,
index=index,
min_itemsize=min_itemsize,
nan_rep=nan_rep,
dropna=dropna,
data_columns=data_columns,
errors=errors,
encoding=encoding,
)
def to_sql(
self,
name: str,
con,
schema=None,
if_exists: str = "fail",
index: bool_t = True,
index_label=None,
chunksize=None,
dtype=None,
method=None,
) -> None:
"""
Write records stored in a DataFrame to a SQL database.
Databases supported by SQLAlchemy [1]_ are supported. Tables can be
newly created, appended to, or overwritten.
Parameters
----------
name : str
Name of SQL table.
con : sqlalchemy.engine.Engine or sqlite3.Connection
Using SQLAlchemy makes it possible to use any DB supported by that
library. Legacy support is provided for sqlite3.Connection objects. The user
is responsible for engine disposal and connection closure for the SQLAlchemy
connectable See `here \
<https://docs.sqlalchemy.org/en/13/core/connections.html>`_.
schema : str, optional
Specify the schema (if database flavor supports this). If None, use
default schema.
if_exists : {'fail', 'replace', 'append'}, default 'fail'
How to behave if the table already exists.
* fail: Raise a ValueError.
* replace: Drop the table before inserting new values.
* append: Insert new values to the existing table.
index : bool, default True
Write DataFrame index as a column. Uses `index_label` as the column
name in the table.
index_label : str or sequence, default None
Column label for index column(s). If None is given (default) and
`index` is True, then the index names are used.
A sequence should be given if the DataFrame uses MultiIndex.
chunksize : int, optional
Specify the number of rows in each batch to be written at a time.
By default, all rows will be written at once.
dtype : dict or scalar, optional
Specifying the datatype for columns. If a dictionary is used, the
keys should be the column names and the values should be the
SQLAlchemy types or strings for the sqlite3 legacy mode. If a
scalar is provided, it will be applied to all columns.
method : {None, 'multi', callable}, optional
Controls the SQL insertion clause used:
* None : Uses standard SQL ``INSERT`` clause (one per row).
* 'multi': Pass multiple values in a single ``INSERT`` clause.
* callable with signature ``(pd_table, conn, keys, data_iter)``.
Details and a sample callable implementation can be found in the
section :ref:`insert method <io.sql.method>`.
.. versionadded:: 0.24.0
Raises
------
ValueError
When the table already exists and `if_exists` is 'fail' (the
default).
See Also
--------
read_sql : Read a DataFrame from a table.
Notes
-----
Timezone aware datetime columns will be written as
``Timestamp with timezone`` type with SQLAlchemy if supported by the
database. Otherwise, the datetimes will be stored as timezone unaware
timestamps local to the original timezone.
.. versionadded:: 0.24.0
References
----------
.. [1] https://docs.sqlalchemy.org
.. [2] https://www.python.org/dev/peps/pep-0249/
Examples
--------
Create an in-memory SQLite database.
>>> from sqlalchemy import create_engine
>>> engine = create_engine('sqlite://', echo=False)
Create a table from scratch with 3 rows.
>>> df = pd.DataFrame({'name' : ['User 1', 'User 2', 'User 3']})
>>> df
name
0 User 1
1 User 2
2 User 3
>>> df.to_sql('users', con=engine)
>>> engine.execute("SELECT * FROM users").fetchall()
[(0, 'User 1'), (1, 'User 2'), (2, 'User 3')]
>>> df1 = pd.DataFrame({'name' : ['User 4', 'User 5']})
>>> df1.to_sql('users', con=engine, if_exists='append')
>>> engine.execute("SELECT * FROM users").fetchall()
[(0, 'User 1'), (1, 'User 2'), (2, 'User 3'),
(0, 'User 4'), (1, 'User 5')]
Overwrite the table with just ``df1``.
>>> df1.to_sql('users', con=engine, if_exists='replace',
... index_label='id')
>>> engine.execute("SELECT * FROM users").fetchall()
[(0, 'User 4'), (1, 'User 5')]
Specify the dtype (especially useful for integers with missing values).
Notice that while pandas is forced to store the data as floating point,
the database supports nullable integers. When fetching the data with
Python, we get back integer scalars.
>>> df = pd.DataFrame({"A": [1, None, 2]})
>>> df
A
0 1.0
1 NaN
2 2.0
>>> from sqlalchemy.types import Integer
>>> df.to_sql('integers', con=engine, index=False,
... dtype={"A": Integer()})
>>> engine.execute("SELECT * FROM integers").fetchall()
[(1,), (None,), (2,)]
"""
from pandas.io import sql
sql.to_sql(
self,
name,
con,
schema=schema,
if_exists=if_exists,
index=index,
index_label=index_label,
chunksize=chunksize,
dtype=dtype,
method=method,
)
def to_pickle(
self,
path,
compression: Optional[str] = "infer",
protocol: int = pickle.HIGHEST_PROTOCOL,
) -> None:
"""
Pickle (serialize) object to file.
Parameters
----------
path : str
File path where the pickled object will be stored.
compression : {'infer', 'gzip', 'bz2', 'zip', 'xz', None}, \
default 'infer'
A string representing the compression to use in the output file. By
default, infers from the file extension in specified path.
protocol : int
Int which indicates which protocol should be used by the pickler,
default HIGHEST_PROTOCOL (see [1]_ paragraph 12.1.2). The possible
values are 0, 1, 2, 3, 4. A negative value for the protocol
parameter is equivalent to setting its value to HIGHEST_PROTOCOL.
.. [1] https://docs.python.org/3/library/pickle.html.
.. versionadded:: 0.21.0.
See Also
--------
read_pickle : Load pickled pandas object (or any object) from file.
DataFrame.to_hdf : Write DataFrame to an HDF5 file.
DataFrame.to_sql : Write DataFrame to a SQL database.
DataFrame.to_parquet : Write a DataFrame to the binary parquet format.
Examples
--------
>>> original_df = pd.DataFrame({"foo": range(5), "bar": range(5, 10)})
>>> original_df
foo bar
0 0 5
1 1 6
2 2 7
3 3 8
4 4 9
>>> original_df.to_pickle("./dummy.pkl")
>>> unpickled_df = pd.read_pickle("./dummy.pkl")
>>> unpickled_df
foo bar
0 0 5
1 1 6
2 2 7
3 3 8
4 4 9
>>> import os
>>> os.remove("./dummy.pkl")
"""
from pandas.io.pickle import to_pickle
to_pickle(self, path, compression=compression, protocol=protocol)
def to_clipboard(
self, excel: bool_t = True, sep: Optional[str] = None, **kwargs
) -> None:
r"""
Copy object to the system clipboard.
Write a text representation of object to the system clipboard.
This can be pasted into Excel, for example.
Parameters
----------
excel : bool, default True
Produce output in a csv format for easy pasting into excel.
- True, use the provided separator for csv pasting.
- False, write a string representation of the object to the clipboard.
sep : str, default ``'\t'``
Field delimiter.
**kwargs
These parameters will be passed to DataFrame.to_csv.
See Also
--------
DataFrame.to_csv : Write a DataFrame to a comma-separated values
(csv) file.
read_clipboard : Read text from clipboard and pass to read_table.
Notes
-----
Requirements for your platform.
- Linux : `xclip`, or `xsel` (with `PyQt4` modules)
- Windows : none
- OS X : none
Examples
--------
Copy the contents of a DataFrame to the clipboard.
>>> df = pd.DataFrame([[1, 2, 3], [4, 5, 6]], columns=['A', 'B', 'C'])
>>> df.to_clipboard(sep=',')
... # Wrote the following to the system clipboard:
... # ,A,B,C
... # 0,1,2,3
... # 1,4,5,6
We can omit the index by passing the keyword `index` and setting
it to false.
>>> df.to_clipboard(sep=',', index=False)
... # Wrote the following to the system clipboard:
... # A,B,C
... # 1,2,3
... # 4,5,6
"""
from pandas.io import clipboards
clipboards.to_clipboard(self, excel=excel, sep=sep, **kwargs)
def to_xarray(self):
"""
Return an xarray object from the pandas object.
Returns
-------
xarray.DataArray or xarray.Dataset
Data in the pandas structure converted to Dataset if the object is
a DataFrame, or a DataArray if the object is a Series.
See Also
--------
DataFrame.to_hdf : Write DataFrame to an HDF5 file.
DataFrame.to_parquet : Write a DataFrame to the binary parquet format.
Notes
-----
See the `xarray docs <https://xarray.pydata.org/en/stable/>`__
Examples
--------
>>> df = pd.DataFrame([('falcon', 'bird', 389.0, 2),
... ('parrot', 'bird', 24.0, 2),
... ('lion', 'mammal', 80.5, 4),
... ('monkey', 'mammal', np.nan, 4)],
... columns=['name', 'class', 'max_speed',
... 'num_legs'])
>>> df
name class max_speed num_legs
0 falcon bird 389.0 2
1 parrot bird 24.0 2
2 lion mammal 80.5 4
3 monkey mammal NaN 4
>>> df.to_xarray()
<xarray.Dataset>
Dimensions: (index: 4)
Coordinates:
* index (index) int64 0 1 2 3
Data variables:
name (index) object 'falcon' 'parrot' 'lion' 'monkey'
class (index) object 'bird' 'bird' 'mammal' 'mammal'
max_speed (index) float64 389.0 24.0 80.5 nan
num_legs (index) int64 2 2 4 4
>>> df['max_speed'].to_xarray()
<xarray.DataArray 'max_speed' (index: 4)>
array([389. , 24. , 80.5, nan])
Coordinates:
* index (index) int64 0 1 2 3
>>> dates = pd.to_datetime(['2018-01-01', '2018-01-01',
... '2018-01-02', '2018-01-02'])
>>> df_multiindex = pd.DataFrame({'date': dates,
... 'animal': ['falcon', 'parrot',
... 'falcon', 'parrot'],
... 'speed': [350, 18, 361, 15]})
>>> df_multiindex = df_multiindex.set_index(['date', 'animal'])
>>> df_multiindex
speed
date animal
2018-01-01 falcon 350
parrot 18
2018-01-02 falcon 361
parrot 15
>>> df_multiindex.to_xarray()
<xarray.Dataset>
Dimensions: (animal: 2, date: 2)
Coordinates:
* date (date) datetime64[ns] 2018-01-01 2018-01-02
* animal (animal) object 'falcon' 'parrot'
Data variables:
speed (date, animal) int64 350 18 361 15
"""
xarray = import_optional_dependency("xarray")
if self.ndim == 1:
return xarray.DataArray.from_series(self)
else:
return xarray.Dataset.from_dataframe(self)
@Substitution(returns=fmt.return_docstring)
def to_latex(
self,
buf=None,
columns=None,
col_space=None,
header=True,
index=True,
na_rep="NaN",
formatters=None,
float_format=None,
sparsify=None,
index_names=True,
bold_rows=False,
column_format=None,
longtable=None,
escape=None,
encoding=None,
decimal=".",
multicolumn=None,
multicolumn_format=None,
multirow=None,
caption=None,
label=None,
):
r"""
Render object to a LaTeX tabular, longtable, or nested table/tabular.
Requires ``\usepackage{booktabs}``. The output can be copy/pasted
into a main LaTeX document or read from an external file
with ``\input{table.tex}``.
.. versionchanged:: 0.20.2
Added to Series.
.. versionchanged:: 1.0.0
Added caption and label arguments.
Parameters
----------
buf : str, Path or StringIO-like, optional, default None
Buffer to write to. If None, the output is returned as a string.
columns : list of label, optional
The subset of columns to write. Writes all columns by default.
col_space : int, optional
The minimum width of each column.
header : bool or list of str, default True
Write out the column names. If a list of strings is given,
it is assumed to be aliases for the column names.
index : bool, default True
Write row names (index).
na_rep : str, default 'NaN'
Missing data representation.
formatters : list of functions or dict of {str: function}, optional
Formatter functions to apply to columns' elements by position or
name. The result of each function must be a unicode string.
List must be of length equal to the number of columns.
float_format : one-parameter function or str, optional, default None
Formatter for floating point numbers. For example
``float_format="%%.2f"`` and ``float_format="{:0.2f}".format`` will
both result in 0.1234 being formatted as 0.12.
sparsify : bool, optional
Set to False for a DataFrame with a hierarchical index to print
every multiindex key at each row. By default, the value will be
read from the config module.
index_names : bool, default True
Prints the names of the indexes.
bold_rows : bool, default False
Make the row labels bold in the output.
column_format : str, optional
The columns format as specified in `LaTeX table format
<https://en.wikibooks.org/wiki/LaTeX/Tables>`__ e.g. 'rcl' for 3
columns. By default, 'l' will be used for all columns except
columns of numbers, which default to 'r'.
longtable : bool, optional
By default, the value will be read from the pandas config
module. Use a longtable environment instead of tabular. Requires
adding a \usepackage{longtable} to your LaTeX preamble.
escape : bool, optional
By default, the value will be read from the pandas config
module. When set to False prevents from escaping latex special
characters in column names.
encoding : str, optional
A string representing the encoding to use in the output file,
defaults to 'utf-8'.
decimal : str, default '.'
Character recognized as decimal separator, e.g. ',' in Europe.
multicolumn : bool, default True
Use \multicolumn to enhance MultiIndex columns.
The default will be read from the config module.
multicolumn_format : str, default 'l'
The alignment for multicolumns, similar to `column_format`
The default will be read from the config module.
multirow : bool, default False
Use \multirow to enhance MultiIndex rows. Requires adding a
\usepackage{multirow} to your LaTeX preamble. Will print
centered labels (instead of top-aligned) across the contained
rows, separating groups via clines. The default will be read
from the pandas config module.
caption : str, optional
The LaTeX caption to be placed inside ``\caption{}`` in the output.
.. versionadded:: 1.0.0
label : str, optional
The LaTeX label to be placed inside ``\label{}`` in the output.
This is used with ``\ref{}`` in the main ``.tex`` file.
.. versionadded:: 1.0.0
%(returns)s
See Also
--------
DataFrame.to_string : Render a DataFrame to a console-friendly
tabular output.
DataFrame.to_html : Render a DataFrame as an HTML table.
Examples
--------
>>> df = pd.DataFrame({'name': ['Raphael', 'Donatello'],
... 'mask': ['red', 'purple'],
... 'weapon': ['sai', 'bo staff']})
>>> print(df.to_latex(index=False)) # doctest: +NORMALIZE_WHITESPACE
\begin{tabular}{lll}
\toprule
name & mask & weapon \\
\midrule
Raphael & red & sai \\
Donatello & purple & bo staff \\
\bottomrule
\end{tabular}
"""
# Get defaults from the pandas config
if self.ndim == 1:
self = self.to_frame()
if longtable is None:
longtable = config.get_option("display.latex.longtable")
if escape is None:
escape = config.get_option("display.latex.escape")
if multicolumn is None:
multicolumn = config.get_option("display.latex.multicolumn")
if multicolumn_format is None:
multicolumn_format = config.get_option("display.latex.multicolumn_format")
if multirow is None:
multirow = config.get_option("display.latex.multirow")
formatter = DataFrameFormatter(
self,
columns=columns,
col_space=col_space,
na_rep=na_rep,
header=header,
index=index,
formatters=formatters,
float_format=float_format,
bold_rows=bold_rows,
sparsify=sparsify,
index_names=index_names,
escape=escape,
decimal=decimal,
)
return formatter.to_latex(
buf=buf,
column_format=column_format,
longtable=longtable,
encoding=encoding,
multicolumn=multicolumn,
multicolumn_format=multicolumn_format,
multirow=multirow,
caption=caption,
label=label,
)
def to_csv(
self,
path_or_buf: Optional[FilePathOrBuffer] = None,
sep: str = ",",
na_rep: str = "",
float_format: Optional[str] = None,
columns: Optional[Sequence[Label]] = None,
header: Union[bool_t, List[str]] = True,
index: bool_t = True,
index_label: Optional[Union[bool_t, str, Sequence[Label]]] = None,
mode: str = "w",
encoding: Optional[str] = None,
compression: Optional[Union[str, Mapping[str, str]]] = "infer",
quoting: Optional[int] = None,
quotechar: str = '"',
line_terminator: Optional[str] = None,
chunksize: Optional[int] = None,
date_format: Optional[str] = None,
doublequote: bool_t = True,
escapechar: Optional[str] = None,
decimal: Optional[str] = ".",
) -> Optional[str]:
r"""
Write object to a comma-separated values (csv) file.
.. versionchanged:: 0.24.0
The order of arguments for Series was changed.
Parameters
----------
path_or_buf : str or file handle, default None
File path or object, if None is provided the result is returned as
a string. If a file object is passed it should be opened with
`newline=''`, disabling universal newlines.
.. versionchanged:: 0.24.0
Was previously named "path" for Series.
sep : str, default ','
String of length 1. Field delimiter for the output file.
na_rep : str, default ''
Missing data representation.
float_format : str, default None
Format string for floating point numbers.
columns : sequence, optional
Columns to write.
header : bool or list of str, default True
Write out the column names. If a list of strings is given it is
assumed to be aliases for the column names.
.. versionchanged:: 0.24.0
Previously defaulted to False for Series.
index : bool, default True
Write row names (index).
index_label : str or sequence, or False, default None
Column label for index column(s) if desired. If None is given, and
`header` and `index` are True, then the index names are used. A
sequence should be given if the object uses MultiIndex. If
False do not print fields for index names. Use index_label=False
for easier importing in R.
mode : str
Python write mode, default 'w'.
encoding : str, optional
A string representing the encoding to use in the output file,
defaults to 'utf-8'.
compression : str or dict, default 'infer'
If str, represents compression mode. If dict, value at 'method' is
the compression mode. Compression mode may be any of the following
possible values: {'infer', 'gzip', 'bz2', 'zip', 'xz', None}. If
compression mode is 'infer' and `path_or_buf` is path-like, then
detect compression mode from the following extensions: '.gz',
'.bz2', '.zip' or '.xz'. (otherwise no compression). If dict given
and mode is 'zip' or inferred as 'zip', other entries passed as
additional compression options.
.. versionchanged:: 1.0.0
May now be a dict with key 'method' as compression mode
and other entries as additional compression options if
compression mode is 'zip'.
quoting : optional constant from csv module
Defaults to csv.QUOTE_MINIMAL. If you have set a `float_format`
then floats are converted to strings and thus csv.QUOTE_NONNUMERIC
will treat them as non-numeric.
quotechar : str, default '\"'
String of length 1. Character used to quote fields.
line_terminator : str, optional
The newline character or character sequence to use in the output
file. Defaults to `os.linesep`, which depends on the OS in which
this method is called ('\n' for linux, '\r\n' for Windows, i.e.).
.. versionchanged:: 0.24.0
chunksize : int or None
Rows to write at a time.
date_format : str, default None
Format string for datetime objects.
doublequote : bool, default True
Control quoting of `quotechar` inside a field.
escapechar : str, default None
String of length 1. Character used to escape `sep` and `quotechar`
when appropriate.
decimal : str, default '.'
Character recognized as decimal separator. E.g. use ',' for
European data.
Returns
-------
None or str
If path_or_buf is None, returns the resulting csv format as a
string. Otherwise returns None.
See Also
--------
read_csv : Load a CSV file into a DataFrame.
to_excel : Write DataFrame to an Excel file.
Examples
--------
>>> df = pd.DataFrame({'name': ['Raphael', 'Donatello'],
... 'mask': ['red', 'purple'],
... 'weapon': ['sai', 'bo staff']})
>>> df.to_csv(index=False)
'name,mask,weapon\nRaphael,red,sai\nDonatello,purple,bo staff\n'
Create 'out.zip' containing 'out.csv'
>>> compression_opts = dict(method='zip',
... archive_name='out.csv') # doctest: +SKIP
>>> df.to_csv('out.zip', index=False,
... compression=compression_opts) # doctest: +SKIP
"""
df = self if isinstance(self, ABCDataFrame) else self.to_frame()
from pandas.io.formats.csvs import CSVFormatter
formatter = CSVFormatter(
df,
path_or_buf,
line_terminator=line_terminator,
sep=sep,
encoding=encoding,
compression=compression,
quoting=quoting,
na_rep=na_rep,
float_format=float_format,
cols=columns,
header=header,
index=index,
index_label=index_label,
mode=mode,
chunksize=chunksize,
quotechar=quotechar,
date_format=date_format,
doublequote=doublequote,
escapechar=escapechar,
decimal=decimal,
)
formatter.save()
if path_or_buf is None:
return formatter.path_or_buf.getvalue()
return None
# ----------------------------------------------------------------------
# Lookup Caching
def _set_as_cached(self, item, cacher) -> None:
"""
Set the _cacher attribute on the calling object with a weakref to
cacher.
"""
self._cacher = (item, weakref.ref(cacher))
def _reset_cacher(self) -> None:
"""
Reset the cacher.
"""
if hasattr(self, "_cacher"):
del self._cacher
def _maybe_cache_changed(self, item, value) -> None:
"""
The object has called back to us saying maybe it has changed.
"""
self._data.set(item, value)
@property
def _is_cached(self) -> bool_t:
"""Return boolean indicating if self is cached or not."""
return getattr(self, "_cacher", None) is not None
def _get_cacher(self):
"""return my cacher or None"""
cacher = getattr(self, "_cacher", None)
if cacher is not None:
cacher = cacher[1]()
return cacher
def _maybe_update_cacher(
self, clear: bool_t = False, verify_is_copy: bool_t = True
) -> None:
"""
See if we need to update our parent cacher if clear, then clear our
cache.
Parameters
----------
clear : bool, default False
Clear the item cache.
verify_is_copy : bool, default True
Provide is_copy checks.
"""
cacher = getattr(self, "_cacher", None)
if cacher is not None:
ref = cacher[1]()
# we are trying to reference a dead referant, hence
# a copy
if ref is None:
del self._cacher
else:
# Note: we need to call ref._maybe_cache_changed even in the
# case where it will raise. (Uh, not clear why)
try:
ref._maybe_cache_changed(cacher[0], self)
except AssertionError:
# ref._data.setitem can raise
# AssertionError because of shape mismatch
pass
if verify_is_copy:
self._check_setitem_copy(stacklevel=5, t="referant")
if clear:
self._clear_item_cache()
def _clear_item_cache(self) -> None:
self._item_cache.clear()
# ----------------------------------------------------------------------
# Indexing Methods
def take(
self: FrameOrSeries, indices, axis=0, is_copy: Optional[bool_t] = None, **kwargs
) -> FrameOrSeries:
"""
Return the elements in the given *positional* indices along an axis.
This means that we are not indexing according to actual values in
the index attribute of the object. We are indexing according to the
actual position of the element in the object.
Parameters
----------
indices : array-like
An array of ints indicating which positions to take.
axis : {0 or 'index', 1 or 'columns', None}, default 0
The axis on which to select elements. ``0`` means that we are
selecting rows, ``1`` means that we are selecting columns.
is_copy : bool
Before pandas 1.0, ``is_copy=False`` can be specified to ensure
that the return value is an actual copy. Starting with pandas 1.0,
``take`` always returns a copy, and the keyword is therefore
deprecated.
.. deprecated:: 1.0.0
**kwargs
For compatibility with :meth:`numpy.take`. Has no effect on the
output.
Returns
-------
taken : same type as caller
An array-like containing the elements taken from the object.
See Also
--------
DataFrame.loc : Select a subset of a DataFrame by labels.
DataFrame.iloc : Select a subset of a DataFrame by positions.
numpy.take : Take elements from an array along an axis.
Examples
--------
>>> df = pd.DataFrame([('falcon', 'bird', 389.0),
... ('parrot', 'bird', 24.0),
... ('lion', 'mammal', 80.5),
... ('monkey', 'mammal', np.nan)],
... columns=['name', 'class', 'max_speed'],
... index=[0, 2, 3, 1])
>>> df
name class max_speed
0 falcon bird 389.0
2 parrot bird 24.0
3 lion mammal 80.5
1 monkey mammal NaN
Take elements at positions 0 and 3 along the axis 0 (default).
Note how the actual indices selected (0 and 1) do not correspond to
our selected indices 0 and 3. That's because we are selecting the 0th
and 3rd rows, not rows whose indices equal 0 and 3.
>>> df.take([0, 3])
name class max_speed
0 falcon bird 389.0
1 monkey mammal NaN
Take elements at indices 1 and 2 along the axis 1 (column selection).
>>> df.take([1, 2], axis=1)
class max_speed
0 bird 389.0
2 bird 24.0
3 mammal 80.5
1 mammal NaN
We may take elements using negative integers for positive indices,
starting from the end of the object, just like with Python lists.
>>> df.take([-1, -2])
name class max_speed
1 monkey mammal NaN
3 lion mammal 80.5
"""
if is_copy is not None:
warnings.warn(
"is_copy is deprecated and will be removed in a future version. "
"'take' always returns a copy, so there is no need to specify this.",
FutureWarning,
stacklevel=2,
)
nv.validate_take(tuple(), kwargs)
self._consolidate_inplace()
new_data = self._data.take(
indices, axis=self._get_block_manager_axis(axis), verify=True
)
return self._constructor(new_data).__finalize__(self)
def _take_with_is_copy(
self: FrameOrSeries, indices, axis=0, **kwargs
) -> FrameOrSeries:
"""
Internal version of the `take` method that sets the `_is_copy`
attribute to keep track of the parent dataframe (using in indexing
for the SettingWithCopyWarning).
See the docstring of `take` for full explanation of the parameters.
"""
result = self.take(indices=indices, axis=axis, **kwargs)
# Maybe set copy if we didn't actually change the index.
if not result._get_axis(axis).equals(self._get_axis(axis)):
result._set_is_copy(self)
return result
def xs(self, key, axis=0, level=None, drop_level: bool_t = True):
"""
Return cross-section from the Series/DataFrame.
This method takes a `key` argument to select data at a particular
level of a MultiIndex.
Parameters
----------
key : label or tuple of label
Label contained in the index, or partially in a MultiIndex.
axis : {0 or 'index', 1 or 'columns'}, default 0
Axis to retrieve cross-section on.
level : object, defaults to first n levels (n=1 or len(key))
In case of a key partially contained in a MultiIndex, indicate
which levels are used. Levels can be referred by label or position.
drop_level : bool, default True
If False, returns object with same levels as self.
Returns
-------
Series or DataFrame
Cross-section from the original Series or DataFrame
corresponding to the selected index levels.
See Also
--------
DataFrame.loc : Access a group of rows and columns
by label(s) or a boolean array.
DataFrame.iloc : Purely integer-location based indexing
for selection by position.
Notes
-----
`xs` can not be used to set values.
MultiIndex Slicers is a generic way to get/set values on
any level or levels.
It is a superset of `xs` functionality, see
:ref:`MultiIndex Slicers <advanced.mi_slicers>`.
Examples
--------
>>> d = {'num_legs': [4, 4, 2, 2],
... 'num_wings': [0, 0, 2, 2],
... 'class': ['mammal', 'mammal', 'mammal', 'bird'],
... 'animal': ['cat', 'dog', 'bat', 'penguin'],
... 'locomotion': ['walks', 'walks', 'flies', 'walks']}
>>> df = pd.DataFrame(data=d)
>>> df = df.set_index(['class', 'animal', 'locomotion'])
>>> df
num_legs num_wings
class animal locomotion
mammal cat walks 4 0
dog walks 4 0
bat flies 2 2
bird penguin walks 2 2
Get values at specified index
>>> df.xs('mammal')
num_legs num_wings
animal locomotion
cat walks 4 0
dog walks 4 0
bat flies 2 2
Get values at several indexes
>>> df.xs(('mammal', 'dog'))
num_legs num_wings
locomotion
walks 4 0
Get values at specified index and level
>>> df.xs('cat', level=1)
num_legs num_wings
class locomotion
mammal walks 4 0
Get values at several indexes and levels
>>> df.xs(('bird', 'walks'),
... level=[0, 'locomotion'])
num_legs num_wings
animal
penguin 2 2
Get values at specified column and axis
>>> df.xs('num_wings', axis=1)
class animal locomotion
mammal cat walks 0
dog walks 0
bat flies 2
bird penguin walks 2
Name: num_wings, dtype: int64
"""
axis = self._get_axis_number(axis)
labels = self._get_axis(axis)
if level is not None:
loc, new_ax = labels.get_loc_level(key, level=level, drop_level=drop_level)
# create the tuple of the indexer
_indexer = [slice(None)] * self.ndim
_indexer[axis] = loc
indexer = tuple(_indexer)
result = self.iloc[indexer]
setattr(result, result._get_axis_name(axis), new_ax)
return result
if axis == 1:
return self[key]
self._consolidate_inplace()
index = self.index
if isinstance(index, MultiIndex):
loc, new_index = self.index.get_loc_level(key, drop_level=drop_level)
else:
loc = self.index.get_loc(key)
if isinstance(loc, np.ndarray):
if loc.dtype == np.bool_:
(inds,) = loc.nonzero()
return self._take_with_is_copy(inds, axis=axis)
else:
return self._take_with_is_copy(loc, axis=axis)
if not is_scalar(loc):
new_index = self.index[loc]
if is_scalar(loc):
# In this case loc should be an integer
if self.ndim == 1:
# if we encounter an array-like and we only have 1 dim
# that means that their are list/ndarrays inside the Series!
# so just return them (GH 6394)
return self._values[loc]
new_values = self._data.fast_xs(loc)
result = self._constructor_sliced(
new_values,
index=self.columns,
name=self.index[loc],
dtype=new_values.dtype,
)
else:
result = self.iloc[loc]
result.index = new_index
# this could be a view
# but only in a single-dtyped view sliceable case
result._set_is_copy(self, copy=not result._is_view)
return result
_xs: Callable = xs
def __getitem__(self, item):
raise AbstractMethodError(self)
def _get_item_cache(self, item):
"""Return the cached item, item represents a label indexer."""
cache = self._item_cache
res = cache.get(item)
if res is None:
values = self._data.get(item)
res = self._box_item_values(item, values)
cache[item] = res
res._set_as_cached(item, self)
# for a chain
res._is_copy = self._is_copy
return res
def _iget_item_cache(self, item):
"""Return the cached item, item represents a positional indexer."""
ax = self._info_axis
if ax.is_unique:
lower = self._get_item_cache(ax[item])
else:
lower = self._take_with_is_copy(item, axis=self._info_axis_number)
return lower
def _box_item_values(self, key, values):
raise AbstractMethodError(self)
def _slice(self: FrameOrSeries, slobj: slice, axis=0) -> FrameOrSeries:
"""
Construct a slice of this container.
Slicing with this method is *always* positional.
"""
assert isinstance(slobj, slice), type(slobj)
axis = self._get_block_manager_axis(axis)
result = self._constructor(self._data.get_slice(slobj, axis=axis))
result = result.__finalize__(self)
# this could be a view
# but only in a single-dtyped view sliceable case
is_copy = axis != 0 or result._is_view
result._set_is_copy(self, copy=is_copy)
return result
def _set_item(self, key, value) -> None:
self._data.set(key, value)
self._clear_item_cache()
def _set_is_copy(self, ref, copy: bool_t = True) -> None:
if not copy:
self._is_copy = None
else:
assert ref is not None
self._is_copy = weakref.ref(ref)
def _check_is_chained_assignment_possible(self) -> bool_t:
"""
Check if we are a view, have a cacher, and are of mixed type.
If so, then force a setitem_copy check.
Should be called just near setting a value
Will return a boolean if it we are a view and are cached, but a
single-dtype meaning that the cacher should be updated following
setting.
"""
if self._is_view and self._is_cached:
ref = self._get_cacher()
if ref is not None and ref._is_mixed_type:
self._check_setitem_copy(stacklevel=4, t="referant", force=True)
return True
elif self._is_copy:
self._check_setitem_copy(stacklevel=4, t="referant")
return False
def _check_setitem_copy(self, stacklevel=4, t="setting", force=False):
"""
Parameters
----------
stacklevel : int, default 4
the level to show of the stack when the error is output
t : str, the type of setting error
force : bool, default False
If True, then force showing an error.
validate if we are doing a setitem on a chained copy.
If you call this function, be sure to set the stacklevel such that the
user will see the error *at the level of setting*
It is technically possible to figure out that we are setting on
a copy even WITH a multi-dtyped pandas object. In other words, some
blocks may be views while other are not. Currently _is_view will ALWAYS
return False for multi-blocks to avoid having to handle this case.
df = DataFrame(np.arange(0,9), columns=['count'])
df['group'] = 'b'
# This technically need not raise SettingWithCopy if both are view
# (which is not # generally guaranteed but is usually True. However,
# this is in general not a good practice and we recommend using .loc.
df.iloc[0:5]['group'] = 'a'
"""
# return early if the check is not needed
if not (force or self._is_copy):
return
value = config.get_option("mode.chained_assignment")
if value is None:
return
# see if the copy is not actually referred; if so, then dissolve
# the copy weakref
if self._is_copy is not None and not isinstance(self._is_copy, str):
r = self._is_copy()
if not gc.get_referents(r) or r.shape == self.shape:
self._is_copy = None
return
# a custom message
if isinstance(self._is_copy, str):
t = self._is_copy
elif t == "referant":
t = (
"\n"
"A value is trying to be set on a copy of a slice from a "
"DataFrame\n\n"
"See the caveats in the documentation: "
"https://pandas.pydata.org/pandas-docs/stable/user_guide/"
"indexing.html#returning-a-view-versus-a-copy"
)
else:
t = (
"\n"
"A value is trying to be set on a copy of a slice from a "
"DataFrame.\n"
"Try using .loc[row_indexer,col_indexer] = value "
"instead\n\nSee the caveats in the documentation: "
"https://pandas.pydata.org/pandas-docs/stable/user_guide/"
"indexing.html#returning-a-view-versus-a-copy"
)
if value == "raise":
raise com.SettingWithCopyError(t)
elif value == "warn":
warnings.warn(t, com.SettingWithCopyWarning, stacklevel=stacklevel)
def __delitem__(self, key) -> None:
"""
Delete item
"""
deleted = False
maybe_shortcut = False
if self.ndim == 2 and isinstance(self.columns, MultiIndex):
try:
maybe_shortcut = key not in self.columns._engine
except TypeError:
pass
if maybe_shortcut:
# Allow shorthand to delete all columns whose first len(key)
# elements match key:
if not isinstance(key, tuple):
key = (key,)
for col in self.columns:
if isinstance(col, tuple) and col[: len(key)] == key:
del self[col]
deleted = True
if not deleted:
# If the above loop ran and didn't delete anything because
# there was no match, this call should raise the appropriate
# exception:
self._data.delete(key)
# delete from the caches
try:
del self._item_cache[key]
except KeyError:
pass
# ----------------------------------------------------------------------
# Unsorted
def get(self, key, default=None):
"""
Get item from object for given key (ex: DataFrame column).
Returns default value if not found.
Parameters
----------
key : object
Returns
-------
value : same type as items contained in object
"""
try:
return self[key]
except (KeyError, ValueError, IndexError):
return default
@property
def _is_view(self):
"""Return boolean indicating if self is view of another array """
return self._data.is_view
def reindex_like(
self: FrameOrSeries,
other,
method: Optional[str] = None,
copy: bool_t = True,
limit=None,
tolerance=None,
) -> FrameOrSeries:
"""
Return an object with matching indices as other object.
Conform the object to the same index on all axes. Optional
filling logic, placing NaN in locations having no value
in the previous index. A new object is produced unless the
new index is equivalent to the current one and copy=False.
Parameters
----------
other : Object of the same data type
Its row and column indices are used to define the new indices
of this object.
method : {None, 'backfill'/'bfill', 'pad'/'ffill', 'nearest'}
Method to use for filling holes in reindexed DataFrame.
Please note: this is only applicable to DataFrames/Series with a
monotonically increasing/decreasing index.
* None (default): don't fill gaps
* pad / ffill: propagate last valid observation forward to next
valid
* backfill / bfill: use next valid observation to fill gap
* nearest: use nearest valid observations to fill gap.
copy : bool, default True
Return a new object, even if the passed indexes are the same.
limit : int, default None
Maximum number of consecutive labels to fill for inexact matches.
tolerance : optional
Maximum distance between original and new labels for inexact
matches. The values of the index at the matching locations most
satisfy the equation ``abs(index[indexer] - target) <= tolerance``.
Tolerance may be a scalar value, which applies the same tolerance
to all values, or list-like, which applies variable tolerance per
element. List-like includes list, tuple, array, Series, and must be
the same size as the index and its dtype must exactly match the
index's type.
.. versionadded:: 0.21.0 (list-like tolerance)
Returns
-------
Series or DataFrame
Same type as caller, but with changed indices on each axis.
See Also
--------
DataFrame.set_index : Set row labels.
DataFrame.reset_index : Remove row labels or move them to new columns.
DataFrame.reindex : Change to new indices or expand indices.
Notes
-----
Same as calling
``.reindex(index=other.index, columns=other.columns,...)``.
Examples
--------
>>> df1 = pd.DataFrame([[24.3, 75.7, 'high'],
... [31, 87.8, 'high'],
... [22, 71.6, 'medium'],
... [35, 95, 'medium']],
... columns=['temp_celsius', 'temp_fahrenheit',
... 'windspeed'],
... index=pd.date_range(start='2014-02-12',
... end='2014-02-15', freq='D'))
>>> df1
temp_celsius temp_fahrenheit windspeed
2014-02-12 24.3 75.7 high
2014-02-13 31.0 87.8 high
2014-02-14 22.0 71.6 medium
2014-02-15 35.0 95.0 medium
>>> df2 = pd.DataFrame([[28, 'low'],
... [30, 'low'],
... [35.1, 'medium']],
... columns=['temp_celsius', 'windspeed'],
... index=pd.DatetimeIndex(['2014-02-12', '2014-02-13',
... '2014-02-15']))
>>> df2
temp_celsius windspeed
2014-02-12 28.0 low
2014-02-13 30.0 low
2014-02-15 35.1 medium
>>> df2.reindex_like(df1)
temp_celsius temp_fahrenheit windspeed
2014-02-12 28.0 NaN low
2014-02-13 30.0 NaN low
2014-02-14 NaN NaN NaN
2014-02-15 35.1 NaN medium
"""
d = other._construct_axes_dict(
axes=self._AXIS_ORDERS,
method=method,
copy=copy,
limit=limit,
tolerance=tolerance,
)
return self.reindex(**d)
def drop(
self,
labels=None,
axis=0,
index=None,
columns=None,
level=None,
inplace: bool_t = False,
errors: str = "raise",
):
inplace = validate_bool_kwarg(inplace, "inplace")
if labels is not None:
if index is not None or columns is not None:
raise ValueError("Cannot specify both 'labels' and 'index'/'columns'")
axis_name = self._get_axis_name(axis)
axes = {axis_name: labels}
elif index is not None or columns is not None:
axes, _ = self._construct_axes_from_arguments((index, columns), {})
else:
raise ValueError(
"Need to specify at least one of 'labels', 'index' or 'columns'"
)
obj = self
for axis, labels in axes.items():
if labels is not None:
obj = obj._drop_axis(labels, axis, level=level, errors=errors)
if inplace:
self._update_inplace(obj)
else:
return obj
def _drop_axis(
self: FrameOrSeries, labels, axis, level=None, errors: str = "raise"
) -> FrameOrSeries:
"""
Drop labels from specified axis. Used in the ``drop`` method
internally.
Parameters
----------
labels : single label or list-like
axis : int or axis name
level : int or level name, default None
For MultiIndex
errors : {'ignore', 'raise'}, default 'raise'
If 'ignore', suppress error and existing labels are dropped.
"""
axis = self._get_axis_number(axis)
axis_name = self._get_axis_name(axis)
axis = self._get_axis(axis)
if axis.is_unique:
if level is not None:
if not isinstance(axis, MultiIndex):
raise AssertionError("axis must be a MultiIndex")
new_axis = axis.drop(labels, level=level, errors=errors)
else:
new_axis = axis.drop(labels, errors=errors)
result = self.reindex(**{axis_name: new_axis})
# Case for non-unique axis
else:
labels = ensure_object(com.index_labels_to_array(labels))
if level is not None:
if not isinstance(axis, MultiIndex):
raise AssertionError("axis must be a MultiIndex")
indexer = ~axis.get_level_values(level).isin(labels)
# GH 18561 MultiIndex.drop should raise if label is absent
if errors == "raise" and indexer.all():
raise KeyError(f"{labels} not found in axis")
else:
indexer = ~axis.isin(labels)
# Check if label doesn't exist along axis
labels_missing = (axis.get_indexer_for(labels) == -1).any()
if errors == "raise" and labels_missing:
raise KeyError(f"{labels} not found in axis")
slicer = [slice(None)] * self.ndim
slicer[self._get_axis_number(axis_name)] = indexer
result = self.loc[tuple(slicer)]
return result
def _update_inplace(self, result, verify_is_copy: bool_t = True) -> None:
"""
Replace self internals with result.
Parameters
----------
verify_is_copy : bool, default True
Provide is_copy checks.
"""
# NOTE: This does *not* call __finalize__ and that's an explicit
# decision that we may revisit in the future.
self._reset_cache()
self._clear_item_cache()
self._data = getattr(result, "_data", result)
self._maybe_update_cacher(verify_is_copy=verify_is_copy)
def add_prefix(self: FrameOrSeries, prefix: str) -> FrameOrSeries:
"""
Prefix labels with string `prefix`.
For Series, the row labels are prefixed.
For DataFrame, the column labels are prefixed.
Parameters
----------
prefix : str
The string to add before each label.
Returns
-------
Series or DataFrame
New Series or DataFrame with updated labels.
See Also
--------
Series.add_suffix: Suffix row labels with string `suffix`.
DataFrame.add_suffix: Suffix column labels with string `suffix`.
Examples
--------
>>> s = pd.Series([1, 2, 3, 4])
>>> s
0 1
1 2
2 3
3 4
dtype: int64
>>> s.add_prefix('item_')
item_0 1
item_1 2
item_2 3
item_3 4
dtype: int64
>>> df = pd.DataFrame({'A': [1, 2, 3, 4], 'B': [3, 4, 5, 6]})
>>> df
A B
0 1 3
1 2 4
2 3 5
3 4 6
>>> df.add_prefix('col_')
col_A col_B
0 1 3
1 2 4
2 3 5
3 4 6
"""
f = functools.partial("{prefix}{}".format, prefix=prefix)
mapper = {self._info_axis_name: f}
return self.rename(**mapper) # type: ignore
def add_suffix(self: FrameOrSeries, suffix: str) -> FrameOrSeries:
"""
Suffix labels with string `suffix`.
For Series, the row labels are suffixed.
For DataFrame, the column labels are suffixed.
Parameters
----------
suffix : str
The string to add after each label.
Returns
-------
Series or DataFrame
New Series or DataFrame with updated labels.
See Also
--------
Series.add_prefix: Prefix row labels with string `prefix`.
DataFrame.add_prefix: Prefix column labels with string `prefix`.
Examples
--------
>>> s = pd.Series([1, 2, 3, 4])
>>> s
0 1
1 2
2 3
3 4
dtype: int64
>>> s.add_suffix('_item')
0_item 1
1_item 2
2_item 3
3_item 4
dtype: int64
>>> df = pd.DataFrame({'A': [1, 2, 3, 4], 'B': [3, 4, 5, 6]})
>>> df
A B
0 1 3
1 2 4
2 3 5
3 4 6
>>> df.add_suffix('_col')
A_col B_col
0 1 3
1 2 4
2 3 5
3 4 6
"""
f = functools.partial("{}{suffix}".format, suffix=suffix)
mapper = {self._info_axis_name: f}
return self.rename(**mapper) # type: ignore
def sort_values(
self,
axis=0,
ascending=True,
inplace: bool_t = False,
kind: str = "quicksort",
na_position: str = "last",
ignore_index: bool_t = False,
):
"""
Sort by the values along either axis.
Parameters
----------%(optional_by)s
axis : %(axes_single_arg)s, default 0
Axis to be sorted.
ascending : bool or list of bool, default True
Sort ascending vs. descending. Specify list for multiple sort
orders. If this is a list of bools, must match the length of
the by.
inplace : bool, default False
If True, perform operation in-place.
kind : {'quicksort', 'mergesort', 'heapsort'}, default 'quicksort'
Choice of sorting algorithm. See also ndarray.np.sort for more
information. `mergesort` is the only stable algorithm. For
DataFrames, this option is only applied when sorting on a single
column or label.
na_position : {'first', 'last'}, default 'last'
Puts NaNs at the beginning if `first`; `last` puts NaNs at the
end.
ignore_index : bool, default False
If True, the resulting axis will be labeled 0, 1, …, n - 1.
.. versionadded:: 1.0.0
Returns
-------
sorted_obj : DataFrame or None
DataFrame with sorted values if inplace=False, None otherwise.
Examples
--------
>>> df = pd.DataFrame({
... 'col1': ['A', 'A', 'B', np.nan, 'D', 'C'],
... 'col2': [2, 1, 9, 8, 7, 4],
... 'col3': [0, 1, 9, 4, 2, 3],
... })
>>> df
col1 col2 col3
0 A 2 0
1 A 1 1
2 B 9 9
3 NaN 8 4
4 D 7 2
5 C 4 3
Sort by col1
>>> df.sort_values(by=['col1'])
col1 col2 col3
0 A 2 0
1 A 1 1
2 B 9 9
5 C 4 3
4 D 7 2
3 NaN 8 4
Sort by multiple columns
>>> df.sort_values(by=['col1', 'col2'])
col1 col2 col3
1 A 1 1
0 A 2 0
2 B 9 9
5 C 4 3
4 D 7 2
3 NaN 8 4
Sort Descending
>>> df.sort_values(by='col1', ascending=False)
col1 col2 col3
4 D 7 2
5 C 4 3
2 B 9 9
0 A 2 0
1 A 1 1
3 NaN 8 4
Putting NAs first
>>> df.sort_values(by='col1', ascending=False, na_position='first')
col1 col2 col3
3 NaN 8 4
4 D 7 2
5 C 4 3
2 B 9 9
0 A 2 0
1 A 1 1
"""
raise AbstractMethodError(self)
def reindex(self: FrameOrSeries, *args, **kwargs) -> FrameOrSeries:
"""
Conform %(klass)s to new index with optional filling logic.
Places NA/NaN in locations having no value in the previous index. A new object
is produced unless the new index is equivalent to the current one and
``copy=False``.
Parameters
----------
%(optional_labels)s
%(axes)s : array-like, optional
New labels / index to conform to, should be specified using
keywords. Preferably an Index object to avoid duplicating data.
%(optional_axis)s
method : {None, 'backfill'/'bfill', 'pad'/'ffill', 'nearest'}
Method to use for filling holes in reindexed DataFrame.
Please note: this is only applicable to DataFrames/Series with a
monotonically increasing/decreasing index.
* None (default): don't fill gaps
* pad / ffill: Propagate last valid observation forward to next
valid.
* backfill / bfill: Use next valid observation to fill gap.
* nearest: Use nearest valid observations to fill gap.
copy : bool, default True
Return a new object, even if the passed indexes are the same.
level : int or name
Broadcast across a level, matching Index values on the
passed MultiIndex level.
fill_value : scalar, default np.NaN
Value to use for missing values. Defaults to NaN, but can be any
"compatible" value.
limit : int, default None
Maximum number of consecutive elements to forward or backward fill.
tolerance : optional
Maximum distance between original and new labels for inexact
matches. The values of the index at the matching locations most
satisfy the equation ``abs(index[indexer] - target) <= tolerance``.
Tolerance may be a scalar value, which applies the same tolerance
to all values, or list-like, which applies variable tolerance per
element. List-like includes list, tuple, array, Series, and must be
the same size as the index and its dtype must exactly match the
index's type.
.. versionadded:: 0.21.0 (list-like tolerance)
Returns
-------
%(klass)s with changed index.
See Also
--------
DataFrame.set_index : Set row labels.
DataFrame.reset_index : Remove row labels or move them to new columns.
DataFrame.reindex_like : Change to same indices as other DataFrame.
Examples
--------
``DataFrame.reindex`` supports two calling conventions
* ``(index=index_labels, columns=column_labels, ...)``
* ``(labels, axis={'index', 'columns'}, ...)``
We *highly* recommend using keyword arguments to clarify your
intent.
Create a dataframe with some fictional data.
>>> index = ['Firefox', 'Chrome', 'Safari', 'IE10', 'Konqueror']
>>> df = pd.DataFrame({'http_status': [200, 200, 404, 404, 301],
... 'response_time': [0.04, 0.02, 0.07, 0.08, 1.0]},
... index=index)
>>> df
http_status response_time
Firefox 200 0.04
Chrome 200 0.02
Safari 404 0.07
IE10 404 0.08
Konqueror 301 1.00
Create a new index and reindex the dataframe. By default
values in the new index that do not have corresponding
records in the dataframe are assigned ``NaN``.
>>> new_index = ['Safari', 'Iceweasel', 'Comodo Dragon', 'IE10',
... 'Chrome']
>>> df.reindex(new_index)
http_status response_time
Safari 404.0 0.07
Iceweasel NaN NaN
Comodo Dragon NaN NaN
IE10 404.0 0.08
Chrome 200.0 0.02
We can fill in the missing values by passing a value to
the keyword ``fill_value``. Because the index is not monotonically
increasing or decreasing, we cannot use arguments to the keyword
``method`` to fill the ``NaN`` values.
>>> df.reindex(new_index, fill_value=0)
http_status response_time
Safari 404 0.07
Iceweasel 0 0.00
Comodo Dragon 0 0.00
IE10 404 0.08
Chrome 200 0.02
>>> df.reindex(new_index, fill_value='missing')
http_status response_time
Safari 404 0.07
Iceweasel missing missing
Comodo Dragon missing missing
IE10 404 0.08
Chrome 200 0.02
We can also reindex the columns.
>>> df.reindex(columns=['http_status', 'user_agent'])
http_status user_agent
Firefox 200 NaN
Chrome 200 NaN
Safari 404 NaN
IE10 404 NaN
Konqueror 301 NaN
Or we can use "axis-style" keyword arguments
>>> df.reindex(['http_status', 'user_agent'], axis="columns")
http_status user_agent
Firefox 200 NaN
Chrome 200 NaN
Safari 404 NaN
IE10 404 NaN
Konqueror 301 NaN
To further illustrate the filling functionality in
``reindex``, we will create a dataframe with a
monotonically increasing index (for example, a sequence
of dates).
>>> date_index = pd.date_range('1/1/2010', periods=6, freq='D')
>>> df2 = pd.DataFrame({"prices": [100, 101, np.nan, 100, 89, 88]},
... index=date_index)
>>> df2
prices
2010-01-01 100.0
2010-01-02 101.0
2010-01-03 NaN
2010-01-04 100.0
2010-01-05 89.0
2010-01-06 88.0
Suppose we decide to expand the dataframe to cover a wider
date range.
>>> date_index2 = pd.date_range('12/29/2009', periods=10, freq='D')
>>> df2.reindex(date_index2)
prices
2009-12-29 NaN
2009-12-30 NaN
2009-12-31 NaN
2010-01-01 100.0
2010-01-02 101.0
2010-01-03 NaN
2010-01-04 100.0
2010-01-05 89.0
2010-01-06 88.0
2010-01-07 NaN
The index entries that did not have a value in the original data frame
(for example, '2009-12-29') are by default filled with ``NaN``.
If desired, we can fill in the missing values using one of several
options.
For example, to back-propagate the last valid value to fill the ``NaN``
values, pass ``bfill`` as an argument to the ``method`` keyword.
>>> df2.reindex(date_index2, method='bfill')
prices
2009-12-29 100.0
2009-12-30 100.0
2009-12-31 100.0
2010-01-01 100.0
2010-01-02 101.0
2010-01-03 NaN
2010-01-04 100.0
2010-01-05 89.0
2010-01-06 88.0
2010-01-07 NaN
Please note that the ``NaN`` value present in the original dataframe
(at index value 2010-01-03) will not be filled by any of the
value propagation schemes. This is because filling while reindexing
does not look at dataframe values, but only compares the original and
desired indexes. If you do want to fill in the ``NaN`` values present
in the original dataframe, use the ``fillna()`` method.
See the :ref:`user guide <basics.reindexing>` for more.
"""
# TODO: Decide if we care about having different examples for different
# kinds
# construct the args
axes, kwargs = self._construct_axes_from_arguments(args, kwargs)
method = missing.clean_reindex_fill_method(kwargs.pop("method", None))
level = kwargs.pop("level", None)
copy = kwargs.pop("copy", True)
limit = kwargs.pop("limit", None)
tolerance = kwargs.pop("tolerance", None)
fill_value = kwargs.pop("fill_value", None)
# Series.reindex doesn't use / need the axis kwarg
# We pop and ignore it here, to make writing Series/Frame generic code
# easier
kwargs.pop("axis", None)
if kwargs:
raise TypeError(
"reindex() got an unexpected keyword "
f'argument "{list(kwargs.keys())[0]}"'
)
self._consolidate_inplace()
# if all axes that are requested to reindex are equal, then only copy
# if indicated must have index names equal here as well as values
if all(
self._get_axis(axis).identical(ax)
for axis, ax in axes.items()
if ax is not None
):
if copy:
return self.copy()
return self
# check if we are a multi reindex
if self._needs_reindex_multi(axes, method, level):
return self._reindex_multi(axes, copy, fill_value)
# perform the reindex on the axes
return self._reindex_axes(
axes, level, limit, tolerance, method, fill_value, copy
).__finalize__(self)
def _reindex_axes(
self: FrameOrSeries, axes, level, limit, tolerance, method, fill_value, copy
) -> FrameOrSeries:
"""Perform the reindex for all the axes."""
obj = self
for a in self._AXIS_ORDERS:
labels = axes[a]
if labels is None:
continue
ax = self._get_axis(a)
new_index, indexer = ax.reindex(
labels, level=level, limit=limit, tolerance=tolerance, method=method
)
axis = self._get_axis_number(a)
obj = obj._reindex_with_indexers(
{axis: [new_index, indexer]},
fill_value=fill_value,
copy=copy,
allow_dups=False,
)
return obj
def _needs_reindex_multi(self, axes, method, level) -> bool_t:
"""Check if we do need a multi reindex."""
return (
(com.count_not_none(*axes.values()) == self._AXIS_LEN)
and method is None
and level is None
and not self._is_mixed_type
)
def _reindex_multi(self, axes, copy, fill_value):
raise AbstractMethodError(self)
def _reindex_with_indexers(
self: FrameOrSeries,
reindexers,
fill_value=None,
copy: bool_t = False,
allow_dups: bool_t = False,
) -> FrameOrSeries:
"""allow_dups indicates an internal call here """
# reindex doing multiple operations on different axes if indicated
new_data = self._data
for axis in sorted(reindexers.keys()):
index, indexer = reindexers[axis]
baxis = self._get_block_manager_axis(axis)
if index is None:
continue
index = ensure_index(index)
if indexer is not None:
indexer = ensure_int64(indexer)
# TODO: speed up on homogeneous DataFrame objects
new_data = new_data.reindex_indexer(
index,
indexer,
axis=baxis,
fill_value=fill_value,
allow_dups=allow_dups,
copy=copy,
)
if copy and new_data is self._data:
new_data = new_data.copy()
return self._constructor(new_data).__finalize__(self)
def filter(
self: FrameOrSeries,
items=None,
like: Optional[str] = None,
regex: Optional[str] = None,
axis=None,
) -> FrameOrSeries:
"""
Subset the dataframe rows or columns according to the specified index labels.
Note that this routine does not filter a dataframe on its
contents. The filter is applied to the labels of the index.
Parameters
----------
items : list-like
Keep labels from axis which are in items.
like : str
Keep labels from axis for which "like in label == True".
regex : str (regular expression)
Keep labels from axis for which re.search(regex, label) == True.
axis : {0 or ‘index’, 1 or ‘columns’, None}, default None
The axis to filter on, expressed either as an index (int)
or axis name (str). By default this is the info axis,
'index' for Series, 'columns' for DataFrame.
Returns
-------
same type as input object
See Also
--------
DataFrame.loc
Notes
-----
The ``items``, ``like``, and ``regex`` parameters are
enforced to be mutually exclusive.
``axis`` defaults to the info axis that is used when indexing
with ``[]``.
Examples
--------
>>> df = pd.DataFrame(np.array(([1, 2, 3], [4, 5, 6])),
... index=['mouse', 'rabbit'],
... columns=['one', 'two', 'three'])
>>> # select columns by name
>>> df.filter(items=['one', 'three'])
one three
mouse 1 3
rabbit 4 6
>>> # select columns by regular expression
>>> df.filter(regex='e$', axis=1)
one three
mouse 1 3
rabbit 4 6
>>> # select rows containing 'bbi'
>>> df.filter(like='bbi', axis=0)
one two three
rabbit 4 5 6
"""
nkw = com.count_not_none(items, like, regex)
if nkw > 1:
raise TypeError(
"Keyword arguments `items`, `like`, or `regex` "
"are mutually exclusive"
)
if axis is None:
axis = self._info_axis_name
labels = self._get_axis(axis)
if items is not None:
name = self._get_axis_name(axis)
return self.reindex(**{name: [r for r in items if r in labels]})
elif like:
def f(x):
return like in ensure_str(x)
values = labels.map(f)
return self.loc(axis=axis)[values]
elif regex:
def f(x):
return matcher.search(ensure_str(x)) is not None
matcher = re.compile(regex)
values = labels.map(f)
return self.loc(axis=axis)[values]
else:
raise TypeError("Must pass either `items`, `like`, or `regex`")
def head(self: FrameOrSeries, n: int = 5) -> FrameOrSeries:
"""
Return the first `n` rows.
This function returns the first `n` rows for the object based
on position. It is useful for quickly testing if your object
has the right type of data in it.
For negative values of `n`, this function returns all rows except
the last `n` rows, equivalent to ``df[:-n]``.
Parameters
----------
n : int, default 5
Number of rows to select.
Returns
-------
same type as caller
The first `n` rows of the caller object.
See Also
--------
DataFrame.tail: Returns the last `n` rows.
Examples
--------
>>> df = pd.DataFrame({'animal': ['alligator', 'bee', 'falcon', 'lion',
... 'monkey', 'parrot', 'shark', 'whale', 'zebra']})
>>> df
animal
0 alligator
1 bee
2 falcon
3 lion
4 monkey
5 parrot
6 shark
7 whale
8 zebra
Viewing the first 5 lines
>>> df.head()
animal
0 alligator
1 bee
2 falcon
3 lion
4 monkey
Viewing the first `n` lines (three in this case)
>>> df.head(3)
animal
0 alligator
1 bee
2 falcon
For negative values of `n`
>>> df.head(-3)
animal
0 alligator
1 bee
2 falcon
3 lion
4 monkey
5 parrot
"""
return self.iloc[:n]
def tail(self: FrameOrSeries, n: int = 5) -> FrameOrSeries:
"""
Return the last `n` rows.
This function returns last `n` rows from the object based on
position. It is useful for quickly verifying data, for example,
after sorting or appending rows.
For negative values of `n`, this function returns all rows except
the first `n` rows, equivalent to ``df[n:]``.
Parameters
----------
n : int, default 5
Number of rows to select.
Returns
-------
type of caller
The last `n` rows of the caller object.
See Also
--------
DataFrame.head : The first `n` rows of the caller object.
Examples
--------
>>> df = pd.DataFrame({'animal': ['alligator', 'bee', 'falcon', 'lion',
... 'monkey', 'parrot', 'shark', 'whale', 'zebra']})
>>> df
animal
0 alligator
1 bee
2 falcon
3 lion
4 monkey
5 parrot
6 shark
7 whale
8 zebra
Viewing the last 5 lines
>>> df.tail()
animal
4 monkey
5 parrot
6 shark
7 whale
8 zebra
Viewing the last `n` lines (three in this case)
>>> df.tail(3)
animal
6 shark
7 whale
8 zebra
For negative values of `n`
>>> df.tail(-3)
animal
3 lion
4 monkey
5 parrot
6 shark
7 whale
8 zebra
"""
if n == 0:
return self.iloc[0:0]
return self.iloc[-n:]
def sample(
self: FrameOrSeries,
n=None,
frac=None,
replace=False,
weights=None,
random_state=None,
axis=None,
) -> FrameOrSeries:
"""
Return a random sample of items from an axis of object.
You can use `random_state` for reproducibility.
Parameters
----------
n : int, optional
Number of items from axis to return. Cannot be used with `frac`.
Default = 1 if `frac` = None.
frac : float, optional
Fraction of axis items to return. Cannot be used with `n`.
replace : bool, default False
Allow or disallow sampling of the same row more than once.
weights : str or ndarray-like, optional
Default 'None' results in equal probability weighting.
If passed a Series, will align with target object on index. Index
values in weights not found in sampled object will be ignored and
index values in sampled object not in weights will be assigned
weights of zero.
If called on a DataFrame, will accept the name of a column
when axis = 0.
Unless weights are a Series, weights must be same length as axis
being sampled.
If weights do not sum to 1, they will be normalized to sum to 1.
Missing values in the weights column will be treated as zero.
Infinite values not allowed.
random_state : int or numpy.random.RandomState, optional
Seed for the random number generator (if int), or numpy RandomState
object.
axis : {0 or ‘index’, 1 or ‘columns’, None}, default None
Axis to sample. Accepts axis number or name. Default is stat axis
for given data type (0 for Series and DataFrames).
Returns
-------
Series or DataFrame
A new object of same type as caller containing `n` items randomly
sampled from the caller object.
See Also
--------
numpy.random.choice: Generates a random sample from a given 1-D numpy
array.
Notes
-----
If `frac` > 1, `replacement` should be set to `True`.
Examples
--------
>>> df = pd.DataFrame({'num_legs': [2, 4, 8, 0],
... 'num_wings': [2, 0, 0, 0],
... 'num_specimen_seen': [10, 2, 1, 8]},
... index=['falcon', 'dog', 'spider', 'fish'])
>>> df
num_legs num_wings num_specimen_seen
falcon 2 2 10
dog 4 0 2
spider 8 0 1
fish 0 0 8
Extract 3 random elements from the ``Series`` ``df['num_legs']``:
Note that we use `random_state` to ensure the reproducibility of
the examples.
>>> df['num_legs'].sample(n=3, random_state=1)
fish 0
spider 8
falcon 2
Name: num_legs, dtype: int64
A random 50% sample of the ``DataFrame`` with replacement:
>>> df.sample(frac=0.5, replace=True, random_state=1)
num_legs num_wings num_specimen_seen
dog 4 0 2
fish 0 0 8
An upsample sample of the ``DataFrame`` with replacement:
Note that `replace` parameter has to be `True` for `frac` parameter > 1.
>>> df.sample(frac=2, replace=True, random_state=1)
num_legs num_wings num_specimen_seen
dog 4 0 2
fish 0 0 8
falcon 2 2 10
falcon 2 2 10
fish 0 0 8
dog 4 0 2
fish 0 0 8
dog 4 0 2
Using a DataFrame column as weights. Rows with larger value in the
`num_specimen_seen` column are more likely to be sampled.
>>> df.sample(n=2, weights='num_specimen_seen', random_state=1)
num_legs num_wings num_specimen_seen
falcon 2 2 10
fish 0 0 8
"""
if axis is None:
axis = self._stat_axis_number
axis = self._get_axis_number(axis)
axis_length = self.shape[axis]
# Process random_state argument
rs = com.random_state(random_state)
# Check weights for compliance
if weights is not None:
# If a series, align with frame
if isinstance(weights, ABCSeries):
weights = weights.reindex(self.axes[axis])
# Strings acceptable if a dataframe and axis = 0
if isinstance(weights, str):
if isinstance(self, ABCDataFrame):
if axis == 0:
try:
weights = self[weights]
except KeyError:
raise KeyError(
"String passed to weights not a valid column"
)
else:
raise ValueError(
"Strings can only be passed to "
"weights when sampling from rows on "
"a DataFrame"
)
else:
raise ValueError(
"Strings cannot be passed as weights "
"when sampling from a Series."
)
weights = pd.Series(weights, dtype="float64")
if len(weights) != axis_length:
raise ValueError(
"Weights and axis to be sampled must be of same length"
)
if (weights == np.inf).any() or (weights == -np.inf).any():
raise ValueError("weight vector may not include `inf` values")
if (weights < 0).any():
raise ValueError("weight vector many not include negative values")
# If has nan, set to zero.
weights = weights.fillna(0)
# Renormalize if don't sum to 1
if weights.sum() != 1:
if weights.sum() != 0:
weights = weights / weights.sum()
else:
raise ValueError("Invalid weights: weights sum to zero")
weights = weights.values
# If no frac or n, default to n=1.
if n is None and frac is None:
n = 1
elif frac is not None and frac > 1 and not replace:
raise ValueError(
"Replace has to be set to `True` when "
"upsampling the population `frac` > 1."
)
elif n is not None and frac is None and n % 1 != 0:
raise ValueError("Only integers accepted as `n` values")
elif n is None and frac is not None:
n = int(round(frac * axis_length))
elif n is not None and frac is not None:
raise ValueError("Please enter a value for `frac` OR `n`, not both")
# Check for negative sizes
if n < 0:
raise ValueError(
"A negative number of rows requested. Please provide positive value."
)
locs = rs.choice(axis_length, size=n, replace=replace, p=weights)
return self.take(locs, axis=axis)
_shared_docs[
"pipe"
] = r"""
Apply func(self, \*args, \*\*kwargs).
Parameters
----------
func : function
Function to apply to the %(klass)s.
``args``, and ``kwargs`` are passed into ``func``.
Alternatively a ``(callable, data_keyword)`` tuple where
``data_keyword`` is a string indicating the keyword of
``callable`` that expects the %(klass)s.
args : iterable, optional
Positional arguments passed into ``func``.
kwargs : mapping, optional
A dictionary of keyword arguments passed into ``func``.
Returns
-------
object : the return type of ``func``.
See Also
--------
DataFrame.apply
DataFrame.applymap
Series.map
Notes
-----
Use ``.pipe`` when chaining together functions that expect
Series, DataFrames or GroupBy objects. Instead of writing
>>> f(g(h(df), arg1=a), arg2=b, arg3=c)
You can write
>>> (df.pipe(h)
... .pipe(g, arg1=a)
... .pipe(f, arg2=b, arg3=c)
... )
If you have a function that takes the data as (say) the second
argument, pass a tuple indicating which keyword expects the
data. For example, suppose ``f`` takes its data as ``arg2``:
>>> (df.pipe(h)
... .pipe(g, arg1=a)
... .pipe((f, 'arg2'), arg1=a, arg3=c)
... )
"""
@Appender(_shared_docs["pipe"] % _shared_doc_kwargs)
def pipe(self, func, *args, **kwargs):
return com.pipe(self, func, *args, **kwargs)
_shared_docs["aggregate"] = dedent(
"""
Aggregate using one or more operations over the specified axis.
%(versionadded)s
Parameters
----------
func : function, str, list or dict
Function to use for aggregating the data. If a function, must either
work when passed a %(klass)s or when passed to %(klass)s.apply.
Accepted combinations are:
- function
- string function name
- list of functions and/or function names, e.g. ``[np.sum, 'mean']``
- dict of axis labels -> functions, function names or list of such.
%(axis)s
*args
Positional arguments to pass to `func`.
**kwargs
Keyword arguments to pass to `func`.
Returns
-------
scalar, Series or DataFrame
The return can be:
* scalar : when Series.agg is called with single function
* Series : when DataFrame.agg is called with a single function
* DataFrame : when DataFrame.agg is called with several functions
Return scalar, Series or DataFrame.
%(see_also)s
Notes
-----
`agg` is an alias for `aggregate`. Use the alias.
A passed user-defined-function will be passed a Series for evaluation.
%(examples)s"""
)
_shared_docs[
"transform"
] = """
Call ``func`` on self producing a %(klass)s with transformed values.
Produced %(klass)s will have same axis length as self.
Parameters
----------
func : function, str, list or dict
Function to use for transforming the data. If a function, must either
work when passed a %(klass)s or when passed to %(klass)s.apply.
Accepted combinations are:
- function
- string function name
- list of functions and/or function names, e.g. ``[np.exp. 'sqrt']``
- dict of axis labels -> functions, function names or list of such.
%(axis)s
*args
Positional arguments to pass to `func`.
**kwargs
Keyword arguments to pass to `func`.
Returns
-------
%(klass)s
A %(klass)s that must have the same length as self.
Raises
------
ValueError : If the returned %(klass)s has a different length than self.
See Also
--------
%(klass)s.agg : Only perform aggregating type operations.
%(klass)s.apply : Invoke function on a %(klass)s.
Examples
--------
>>> df = pd.DataFrame({'A': range(3), 'B': range(1, 4)})
>>> df
A B
0 0 1
1 1 2
2 2 3
>>> df.transform(lambda x: x + 1)
A B
0 1 2
1 2 3
2 3 4
Even though the resulting %(klass)s must have the same length as the
input %(klass)s, it is possible to provide several input functions:
>>> s = pd.Series(range(3))
>>> s
0 0
1 1
2 2
dtype: int64
>>> s.transform([np.sqrt, np.exp])
sqrt exp
0 0.000000 1.000000
1 1.000000 2.718282
2 1.414214 7.389056
"""
# ----------------------------------------------------------------------
# Attribute access
def __finalize__(
self: FrameOrSeries, other, method=None, **kwargs
) -> FrameOrSeries:
"""
Propagate metadata from other to self.
Parameters
----------
other : the object from which to get the attributes that we are going
to propagate
method : optional, a passed method name ; possibly to take different
types of propagation actions based on this
"""
if isinstance(other, NDFrame):
for name in other.attrs:
self.attrs[name] = other.attrs[name]
# For subclasses using _metadata.
for name in self._metadata:
assert isinstance(name, str)
object.__setattr__(self, name, getattr(other, name, None))
return self
def __getattr__(self, name: str):
"""
After regular attribute access, try looking up the name
This allows simpler access to columns for interactive use.
"""
# Note: obj.x will always call obj.__getattribute__('x') prior to
# calling obj.__getattr__('x').
if (
name in self._internal_names_set
or name in self._metadata
or name in self._accessors
):
return object.__getattribute__(self, name)
else:
if self._info_axis._can_hold_identifiers_and_holds_name(name):
return self[name]
return object.__getattribute__(self, name)
def __setattr__(self, name: str, value) -> None:
"""
After regular attribute access, try setting the name
This allows simpler access to columns for interactive use.
"""
# first try regular attribute access via __getattribute__, so that
# e.g. ``obj.x`` and ``obj.x = 4`` will always reference/modify
# the same attribute.
try:
object.__getattribute__(self, name)
return object.__setattr__(self, name, value)
except AttributeError:
pass
# if this fails, go on to more involved attribute setting
# (note that this matches __getattr__, above).
if name in self._internal_names_set:
object.__setattr__(self, name, value)
elif name in self._metadata:
object.__setattr__(self, name, value)
else:
try:
existing = getattr(self, name)
if isinstance(existing, Index):
object.__setattr__(self, name, value)
elif name in self._info_axis:
self[name] = value
else:
object.__setattr__(self, name, value)
except (AttributeError, TypeError):
if isinstance(self, ABCDataFrame) and (is_list_like(value)):
warnings.warn(
"Pandas doesn't allow columns to be "
"created via a new attribute name - see "
"https://pandas.pydata.org/pandas-docs/"
"stable/indexing.html#attribute-access",
stacklevel=2,
)
object.__setattr__(self, name, value)
def _dir_additions(self):
"""
add the string-like attributes from the info_axis.
If info_axis is a MultiIndex, it's first level values are used.
"""
additions = {
c
for c in self._info_axis.unique(level=0)[:100]
if isinstance(c, str) and c.isidentifier()
}
return super()._dir_additions().union(additions)
# ----------------------------------------------------------------------
# Consolidation of internals
def _protect_consolidate(self, f):
"""
Consolidate _data -- if the blocks have changed, then clear the
cache
"""
blocks_before = len(self._data.blocks)
result = f()
if len(self._data.blocks) != blocks_before:
self._clear_item_cache()
return result
def _consolidate_inplace(self) -> None:
"""Consolidate data in place and return None"""
def f():
self._data = self._data.consolidate()
self._protect_consolidate(f)
def _consolidate(self, inplace: bool_t = False):
"""
Compute NDFrame with "consolidated" internals (data of each dtype
grouped together in a single ndarray).
Parameters
----------
inplace : bool, default False
If False return new object, otherwise modify existing object.
Returns
-------
consolidated : same type as caller
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if inplace:
self._consolidate_inplace()
else:
f = lambda: self._data.consolidate()
cons_data = self._protect_consolidate(f)
return self._constructor(cons_data).__finalize__(self)
@property
def _is_mixed_type(self):
f = lambda: self._data.is_mixed_type
return self._protect_consolidate(f)
@property
def _is_numeric_mixed_type(self):
f = lambda: self._data.is_numeric_mixed_type
return self._protect_consolidate(f)
def _check_inplace_setting(self, value) -> bool_t:
""" check whether we allow in-place setting with this type of value """
if self._is_mixed_type:
if not self._is_numeric_mixed_type:
# allow an actual np.nan thru
if is_float(value) and np.isnan(value):
return True
raise TypeError(
"Cannot do inplace boolean setting on "
"mixed-types with a non np.nan value"
)
return True
def _get_numeric_data(self):
return self._constructor(self._data.get_numeric_data()).__finalize__(self)
def _get_bool_data(self):
return self._constructor(self._data.get_bool_data()).__finalize__(self)
# ----------------------------------------------------------------------
# Internal Interface Methods
@property
def values(self) -> np.ndarray:
"""
Return a Numpy representation of the DataFrame.
.. warning::
We recommend using :meth:`DataFrame.to_numpy` instead.
Only the values in the DataFrame will be returned, the axes labels
will be removed.
Returns
-------
numpy.ndarray
The values of the DataFrame.
See Also
--------
DataFrame.to_numpy : Recommended alternative to this method.
DataFrame.index : Retrieve the index labels.
DataFrame.columns : Retrieving the column names.
Notes
-----
The dtype will be a lower-common-denominator dtype (implicit
upcasting); that is to say if the dtypes (even of numeric types)
are mixed, the one that accommodates all will be chosen. Use this
with care if you are not dealing with the blocks.
e.g. If the dtypes are float16 and float32, dtype will be upcast to
float32. If dtypes are int32 and uint8, dtype will be upcast to
int32. By :func:`numpy.find_common_type` convention, mixing int64
and uint64 will result in a float64 dtype.
Examples
--------
A DataFrame where all columns are the same type (e.g., int64) results
in an array of the same type.
>>> df = pd.DataFrame({'age': [ 3, 29],
... 'height': [94, 170],
... 'weight': [31, 115]})
>>> df
age height weight
0 3 94 31
1 29 170 115
>>> df.dtypes
age int64
height int64
weight int64
dtype: object
>>> df.values
array([[ 3, 94, 31],
[ 29, 170, 115]], dtype=int64)
A DataFrame with mixed type columns(e.g., str/object, int64, float32)
results in an ndarray of the broadest type that accommodates these
mixed types (e.g., object).
>>> df2 = pd.DataFrame([('parrot', 24.0, 'second'),
... ('lion', 80.5, 1),
... ('monkey', np.nan, None)],
... columns=('name', 'max_speed', 'rank'))
>>> df2.dtypes
name object
max_speed float64
rank object
dtype: object
>>> df2.values
array([['parrot', 24.0, 'second'],
['lion', 80.5, 1],
['monkey', nan, None]], dtype=object)
"""
self._consolidate_inplace()
return self._data.as_array(transpose=self._AXIS_REVERSED)
@property
def _values(self) -> np.ndarray:
"""internal implementation"""
return self.values
def _internal_get_values(self) -> np.ndarray:
"""
Return an ndarray after converting sparse values to dense.
This is the same as ``.values`` for non-sparse data. For sparse
data contained in a `SparseArray`, the data are first
converted to a dense representation.
Returns
-------
numpy.ndarray
Numpy representation of DataFrame.
See Also
--------
values : Numpy representation of DataFrame.
SparseArray : Container for sparse data.
"""
return self.values
@property
def dtypes(self):
"""
Return the dtypes in the DataFrame.
This returns a Series with the data type of each column.
The result's index is the original DataFrame's columns. Columns
with mixed types are stored with the ``object`` dtype. See
:ref:`the User Guide <basics.dtypes>` for more.
Returns
-------
pandas.Series
The data type of each column.
Examples
--------
>>> df = pd.DataFrame({'float': [1.0],
... 'int': [1],
... 'datetime': [pd.Timestamp('20180310')],
... 'string': ['foo']})
>>> df.dtypes
float float64
int int64
datetime datetime64[ns]
string object
dtype: object
"""
from pandas import Series
return Series(self._data.get_dtypes(), index=self._info_axis, dtype=np.object_)
def _to_dict_of_blocks(self, copy: bool_t = True):
"""
Return a dict of dtype -> Constructor Types that
each is a homogeneous dtype.
Internal ONLY
"""
return {
k: self._constructor(v).__finalize__(self)
for k, v, in self._data.to_dict(copy=copy).items()
}
def astype(
self: FrameOrSeries, dtype, copy: bool_t = True, errors: str = "raise"
) -> FrameOrSeries:
"""
Cast a pandas object to a specified dtype ``dtype``.
Parameters
----------
dtype : data type, or dict of column name -> data type
Use a numpy.dtype or Python type to cast entire pandas object to
the same type. Alternatively, use {col: dtype, ...}, where col is a
column label and dtype is a numpy.dtype or Python type to cast one
or more of the DataFrame's columns to column-specific types.
copy : bool, default True
Return a copy when ``copy=True`` (be very careful setting
``copy=False`` as changes to values then may propagate to other
pandas objects).
errors : {'raise', 'ignore'}, default 'raise'
Control raising of exceptions on invalid data for provided dtype.
- ``raise`` : allow exceptions to be raised
- ``ignore`` : suppress exceptions. On error return original object.
Returns
-------
casted : same type as caller
See Also
--------
to_datetime : Convert argument to datetime.
to_timedelta : Convert argument to timedelta.
to_numeric : Convert argument to a numeric type.
numpy.ndarray.astype : Cast a numpy array to a specified type.
Examples
--------
Create a DataFrame:
>>> d = {'col1': [1, 2], 'col2': [3, 4]}
>>> df = pd.DataFrame(data=d)
>>> df.dtypes
col1 int64
col2 int64
dtype: object
Cast all columns to int32:
>>> df.astype('int32').dtypes
col1 int32
col2 int32
dtype: object
Cast col1 to int32 using a dictionary:
>>> df.astype({'col1': 'int32'}).dtypes
col1 int32
col2 int64
dtype: object
Create a series:
>>> ser = pd.Series([1, 2], dtype='int32')
>>> ser
0 1
1 2
dtype: int32
>>> ser.astype('int64')
0 1
1 2
dtype: int64
Convert to categorical type:
>>> ser.astype('category')
0 1
1 2
dtype: category
Categories (2, int64): [1, 2]
Convert to ordered categorical type with custom ordering:
>>> cat_dtype = pd.api.types.CategoricalDtype(
... categories=[2, 1], ordered=True)
>>> ser.astype(cat_dtype)
0 1
1 2
dtype: category
Categories (2, int64): [2 < 1]
Note that using ``copy=False`` and changing data on a new
pandas object may propagate changes:
>>> s1 = pd.Series([1, 2])
>>> s2 = s1.astype('int64', copy=False)
>>> s2[0] = 10
>>> s1 # note that s1[0] has changed too
0 10
1 2
dtype: int64
"""
if is_dict_like(dtype):
if self.ndim == 1: # i.e. Series
if len(dtype) > 1 or self.name not in dtype:
raise KeyError(
"Only the Series name can be used for "
"the key in Series dtype mappings."
)
new_type = dtype[self.name]
return self.astype(new_type, copy, errors)
for col_name in dtype.keys():
if col_name not in self:
raise KeyError(
"Only a column name can be used for the "
"key in a dtype mappings argument."
)
results = []
for col_name, col in self.items():
if col_name in dtype:
results.append(
col.astype(dtype=dtype[col_name], copy=copy, errors=errors)
)
else:
results.append(col.copy() if copy else col)
elif is_extension_array_dtype(dtype) and self.ndim > 1:
# GH 18099/22869: columnwise conversion to extension dtype
# GH 24704: use iloc to handle duplicate column names
results = [
self.iloc[:, i].astype(dtype, copy=copy)
for i in range(len(self.columns))
]
else:
# else, only a single dtype is given
new_data = self._data.astype(dtype=dtype, copy=copy, errors=errors)
return self._constructor(new_data).__finalize__(self)
# GH 19920: retain column metadata after concat
result = pd.concat(results, axis=1, copy=False)
result.columns = self.columns
return result
def copy(self: FrameOrSeries, deep: bool_t = True) -> FrameOrSeries:
"""
Make a copy of this object's indices and data.
When ``deep=True`` (default), a new object will be created with a
copy of the calling object's data and indices. Modifications to
the data or indices of the copy will not be reflected in the
original object (see notes below).
When ``deep=False``, a new object will be created without copying
the calling object's data or index (only references to the data
and index are copied). Any changes to the data of the original
will be reflected in the shallow copy (and vice versa).
Parameters
----------
deep : bool, default True
Make a deep copy, including a copy of the data and the indices.
With ``deep=False`` neither the indices nor the data are copied.
Returns
-------
copy : Series or DataFrame
Object type matches caller.
Notes
-----
When ``deep=True``, data is copied but actual Python objects
will not be copied recursively, only the reference to the object.
This is in contrast to `copy.deepcopy` in the Standard Library,
which recursively copies object data (see examples below).
While ``Index`` objects are copied when ``deep=True``, the underlying
numpy array is not copied for performance reasons. Since ``Index`` is
immutable, the underlying data can be safely shared and a copy
is not needed.
Examples
--------
>>> s = pd.Series([1, 2], index=["a", "b"])
>>> s
a 1
b 2
dtype: int64
>>> s_copy = s.copy()
>>> s_copy
a 1
b 2
dtype: int64
**Shallow copy versus default (deep) copy:**
>>> s = pd.Series([1, 2], index=["a", "b"])
>>> deep = s.copy()
>>> shallow = s.copy(deep=False)
Shallow copy shares data and index with original.
>>> s is shallow
False
>>> s.values is shallow.values and s.index is shallow.index
True
Deep copy has own copy of data and index.
>>> s is deep
False
>>> s.values is deep.values or s.index is deep.index
False
Updates to the data shared by shallow copy and original is reflected
in both; deep copy remains unchanged.
>>> s[0] = 3
>>> shallow[1] = 4
>>> s
a 3
b 4
dtype: int64
>>> shallow
a 3
b 4
dtype: int64
>>> deep
a 1
b 2
dtype: int64
Note that when copying an object containing Python objects, a deep copy
will copy the data, but will not do so recursively. Updating a nested
data object will be reflected in the deep copy.
>>> s = pd.Series([[1, 2], [3, 4]])
>>> deep = s.copy()
>>> s[0][0] = 10
>>> s
0 [10, 2]
1 [3, 4]
dtype: object
>>> deep
0 [10, 2]
1 [3, 4]
dtype: object
"""
data = self._data.copy(deep=deep)
return self._constructor(data).__finalize__(self)
def __copy__(self: FrameOrSeries, deep: bool_t = True) -> FrameOrSeries:
return self.copy(deep=deep)
def __deepcopy__(self: FrameOrSeries, memo=None) -> FrameOrSeries:
"""
Parameters
----------
memo, default None
Standard signature. Unused
"""
return self.copy(deep=True)
def _convert(
self: FrameOrSeries,
datetime: bool_t = False,
numeric: bool_t = False,
timedelta: bool_t = False,
coerce: bool_t = False,
copy: bool_t = True,
) -> FrameOrSeries:
"""
Attempt to infer better dtype for object columns
Parameters
----------
datetime : bool, default False
If True, convert to date where possible.
numeric : bool, default False
If True, attempt to convert to numbers (including strings), with
unconvertible values becoming NaN.
timedelta : bool, default False
If True, convert to timedelta where possible.
coerce : bool, default False
If True, force conversion with unconvertible values converted to
nulls (NaN or NaT).
copy : bool, default True
If True, return a copy even if no copy is necessary (e.g. no
conversion was done). Note: This is meant for internal use, and
should not be confused with inplace.
Returns
-------
converted : same as input object
"""
validate_bool_kwarg(datetime, "datetime")
validate_bool_kwarg(numeric, "numeric")
validate_bool_kwarg(timedelta, "timedelta")
validate_bool_kwarg(coerce, "coerce")
validate_bool_kwarg(copy, "copy")
return self._constructor(
self._data.convert(
datetime=datetime,
numeric=numeric,
timedelta=timedelta,
coerce=coerce,
copy=copy,
)
).__finalize__(self)
def infer_objects(self: FrameOrSeries) -> FrameOrSeries:
"""
Attempt to infer better dtypes for object columns.
Attempts soft conversion of object-dtyped
columns, leaving non-object and unconvertible
columns unchanged. The inference rules are the
same as during normal Series/DataFrame construction.
.. versionadded:: 0.21.0
Returns
-------
converted : same type as input object
See Also
--------
to_datetime : Convert argument to datetime.
to_timedelta : Convert argument to timedelta.
to_numeric : Convert argument to numeric type.
convert_dtypes : Convert argument to best possible dtype.
Examples
--------
>>> df = pd.DataFrame({"A": ["a", 1, 2, 3]})
>>> df = df.iloc[1:]
>>> df
A
1 1
2 2
3 3
>>> df.dtypes
A object
dtype: object
>>> df.infer_objects().dtypes
A int64
dtype: object
"""
# numeric=False necessary to only soft convert;
# python objects will still be converted to
# native numpy numeric types
return self._constructor(
self._data.convert(
datetime=True, numeric=False, timedelta=True, coerce=False, copy=True
)
).__finalize__(self)
def convert_dtypes(
self: FrameOrSeries,
infer_objects: bool_t = True,
convert_string: bool_t = True,
convert_integer: bool_t = True,
convert_boolean: bool_t = True,
) -> FrameOrSeries:
"""
Convert columns to best possible dtypes using dtypes supporting ``pd.NA``.
.. versionadded:: 1.0.0
Parameters
----------
infer_objects : bool, default True
Whether object dtypes should be converted to the best possible types.
convert_string : bool, default True
Whether object dtypes should be converted to ``StringDtype()``.
convert_integer : bool, default True
Whether, if possible, conversion can be done to integer extension types.
convert_boolean : bool, defaults True
Whether object dtypes should be converted to ``BooleanDtypes()``.
Returns
-------
Series or DataFrame
Copy of input object with new dtype.
See Also
--------
infer_objects : Infer dtypes of objects.
to_datetime : Convert argument to datetime.
to_timedelta : Convert argument to timedelta.
to_numeric : Convert argument to a numeric type.
Notes
-----
By default, ``convert_dtypes`` will attempt to convert a Series (or each
Series in a DataFrame) to dtypes that support ``pd.NA``. By using the options
``convert_string``, ``convert_integer``, and ``convert_boolean``, it is
possible to turn off individual conversions to ``StringDtype``, the integer
extension types or ``BooleanDtype``, respectively.
For object-dtyped columns, if ``infer_objects`` is ``True``, use the inference
rules as during normal Series/DataFrame construction. Then, if possible,
convert to ``StringDtype``, ``BooleanDtype`` or an appropriate integer extension
type, otherwise leave as ``object``.
If the dtype is integer, convert to an appropriate integer extension type.
If the dtype is numeric, and consists of all integers, convert to an
appropriate integer extension type.
In the future, as new dtypes are added that support ``pd.NA``, the results
of this method will change to support those new dtypes.
Examples
--------
>>> df = pd.DataFrame(
... {
... "a": pd.Series([1, 2, 3], dtype=np.dtype("int32")),
... "b": pd.Series(["x", "y", "z"], dtype=np.dtype("O")),
... "c": pd.Series([True, False, np.nan], dtype=np.dtype("O")),
... "d": pd.Series(["h", "i", np.nan], dtype=np.dtype("O")),
... "e": pd.Series([10, np.nan, 20], dtype=np.dtype("float")),
... "f": pd.Series([np.nan, 100.5, 200], dtype=np.dtype("float")),
... }
... )
Start with a DataFrame with default dtypes.
>>> df
a b c d e f
0 1 x True h 10.0 NaN
1 2 y False i NaN 100.5
2 3 z NaN NaN 20.0 200.0
>>> df.dtypes
a int32
b object
c object
d object
e float64
f float64
dtype: object
Convert the DataFrame to use best possible dtypes.
>>> dfn = df.convert_dtypes()
>>> dfn
a b c d e f
0 1 x True h 10 NaN
1 2 y False i <NA> 100.5
2 3 z <NA> <NA> 20 200.0
>>> dfn.dtypes
a Int32
b string
c boolean
d string
e Int64
f float64
dtype: object
Start with a Series of strings and missing data represented by ``np.nan``.
>>> s = pd.Series(["a", "b", np.nan])
>>> s
0 a
1 b
2 NaN
dtype: object
Obtain a Series with dtype ``StringDtype``.
>>> s.convert_dtypes()
0 a
1 b
2 <NA>
dtype: string
"""
if self.ndim == 1:
return self._convert_dtypes(
infer_objects, convert_string, convert_integer, convert_boolean
)
else:
results = [
col._convert_dtypes(
infer_objects, convert_string, convert_integer, convert_boolean
)
for col_name, col in self.items()
]
result = pd.concat(results, axis=1, copy=False)
return result
# ----------------------------------------------------------------------
# Filling NA's
@doc(**_shared_doc_kwargs)
def fillna(
self: FrameOrSeries,
value=None,
method=None,
axis=None,
inplace: bool_t = False,
limit=None,
downcast=None,
) -> Optional[FrameOrSeries]:
"""
Fill NA/NaN values using the specified method.
Parameters
----------
value : scalar, dict, Series, or DataFrame
Value to use to fill holes (e.g. 0), alternately a
dict/Series/DataFrame of values specifying which value to use for
each index (for a Series) or column (for a DataFrame). Values not
in the dict/Series/DataFrame will not be filled. This value cannot
be a list.
method : {{'backfill', 'bfill', 'pad', 'ffill', None}}, default None
Method to use for filling holes in reindexed Series
pad / ffill: propagate last valid observation forward to next valid
backfill / bfill: use next valid observation to fill gap.
axis : {axes_single_arg}
Axis along which to fill missing values.
inplace : bool, default False
If True, fill in-place. Note: this will modify any
other views on this object (e.g., a no-copy slice for a column in a
DataFrame).
limit : int, default None
If method is specified, this is the maximum number of consecutive
NaN values to forward/backward fill. In other words, if there is
a gap with more than this number of consecutive NaNs, it will only
be partially filled. If method is not specified, this is the
maximum number of entries along the entire axis where NaNs will be
filled. Must be greater than 0 if not None.
downcast : dict, default is None
A dict of item->dtype of what to downcast if possible,
or the string 'infer' which will try to downcast to an appropriate
equal type (e.g. float64 to int64 if possible).
Returns
-------
{klass} or None
Object with missing values filled or None if ``inplace=True``.
See Also
--------
interpolate : Fill NaN values using interpolation.
reindex : Conform object to new index.
asfreq : Convert TimeSeries to specified frequency.
Examples
--------
>>> df = pd.DataFrame([[np.nan, 2, np.nan, 0],
... [3, 4, np.nan, 1],
... [np.nan, np.nan, np.nan, 5],
... [np.nan, 3, np.nan, 4]],
... columns=list('ABCD'))
>>> df
A B C D
0 NaN 2.0 NaN 0
1 3.0 4.0 NaN 1
2 NaN NaN NaN 5
3 NaN 3.0 NaN 4
Replace all NaN elements with 0s.
>>> df.fillna(0)
A B C D
0 0.0 2.0 0.0 0
1 3.0 4.0 0.0 1
2 0.0 0.0 0.0 5
3 0.0 3.0 0.0 4
We can also propagate non-null values forward or backward.
>>> df.fillna(method='ffill')
A B C D
0 NaN 2.0 NaN 0
1 3.0 4.0 NaN 1
2 3.0 4.0 NaN 5
3 3.0 3.0 NaN 4
Replace all NaN elements in column 'A', 'B', 'C', and 'D', with 0, 1,
2, and 3 respectively.
>>> values = {{'A': 0, 'B': 1, 'C': 2, 'D': 3}}
>>> df.fillna(value=values)
A B C D
0 0.0 2.0 2.0 0
1 3.0 4.0 2.0 1
2 0.0 1.0 2.0 5
3 0.0 3.0 2.0 4
Only replace the first NaN element.
>>> df.fillna(value=values, limit=1)
A B C D
0 0.0 2.0 2.0 0
1 3.0 4.0 NaN 1
2 NaN 1.0 NaN 5
3 NaN 3.0 NaN 4
"""
inplace = validate_bool_kwarg(inplace, "inplace")
value, method = validate_fillna_kwargs(value, method)
self._consolidate_inplace()
# set the default here, so functions examining the signaure
# can detect if something was set (e.g. in groupby) (GH9221)
if axis is None:
axis = 0
axis = self._get_axis_number(axis)
if value is None:
if self._is_mixed_type and axis == 1:
if inplace:
raise NotImplementedError()
result = self.T.fillna(method=method, limit=limit).T
# need to downcast here because of all of the transposes
result._data = result._data.downcast()
return result
new_data = self._data.interpolate(
method=method,
axis=axis,
limit=limit,
inplace=inplace,
coerce=True,
downcast=downcast,
)
else:
if len(self._get_axis(axis)) == 0:
return self
if self.ndim == 1:
if isinstance(value, (dict, ABCSeries)):
value = create_series_with_explicit_dtype(
value, dtype_if_empty=object
)
elif not is_list_like(value):
pass
else:
raise TypeError(
'"value" parameter must be a scalar, dict '
"or Series, but you passed a "
f'"{type(value).__name__}"'
)
new_data = self._data.fillna(
value=value, limit=limit, inplace=inplace, downcast=downcast
)
elif isinstance(value, (dict, ABCSeries)):
if axis == 1:
raise NotImplementedError(
"Currently only can fill "
"with dict/Series column "
"by column"
)
result = self if inplace else self.copy()
for k, v in value.items():
if k not in result:
continue
obj = result[k]
obj.fillna(v, limit=limit, inplace=True, downcast=downcast)
return result if not inplace else None
elif not is_list_like(value):
new_data = self._data.fillna(
value=value, limit=limit, inplace=inplace, downcast=downcast
)
elif isinstance(value, ABCDataFrame) and self.ndim == 2:
new_data = self.where(self.notna(), value)
else:
raise ValueError(f"invalid fill value with a {type(value)}")
if inplace:
self._update_inplace(new_data)
return None
else:
return self._constructor(new_data).__finalize__(self)
def ffill(
self: FrameOrSeries,
axis=None,
inplace: bool_t = False,
limit=None,
downcast=None,
) -> Optional[FrameOrSeries]:
"""
Synonym for :meth:`DataFrame.fillna` with ``method='ffill'``.
Returns
-------
%(klass)s or None
Object with missing values filled or None if ``inplace=True``.
"""
return self.fillna(
method="ffill", axis=axis, inplace=inplace, limit=limit, downcast=downcast
)
def bfill(
self: FrameOrSeries,
axis=None,
inplace: bool_t = False,
limit=None,
downcast=None,
) -> Optional[FrameOrSeries]:
"""
Synonym for :meth:`DataFrame.fillna` with ``method='bfill'``.
Returns
-------
%(klass)s or None
Object with missing values filled or None if ``inplace=True``.
"""
return self.fillna(
method="bfill", axis=axis, inplace=inplace, limit=limit, downcast=downcast
)
_shared_docs[
"replace"
] = """
Replace values given in `to_replace` with `value`.
Values of the %(klass)s are replaced with other values dynamically.
This differs from updating with ``.loc`` or ``.iloc``, which require
you to specify a location to update with some value.
Parameters
----------
to_replace : str, regex, list, dict, Series, int, float, or None
How to find the values that will be replaced.
* numeric, str or regex:
- numeric: numeric values equal to `to_replace` will be
replaced with `value`
- str: string exactly matching `to_replace` will be replaced
with `value`
- regex: regexs matching `to_replace` will be replaced with
`value`
* list of str, regex, or numeric:
- First, if `to_replace` and `value` are both lists, they
**must** be the same length.
- Second, if ``regex=True`` then all of the strings in **both**
lists will be interpreted as regexs otherwise they will match
directly. This doesn't matter much for `value` since there
are only a few possible substitution regexes you can use.
- str, regex and numeric rules apply as above.
* dict:
- Dicts can be used to specify different replacement values
for different existing values. For example,
``{'a': 'b', 'y': 'z'}`` replaces the value 'a' with 'b' and
'y' with 'z'. To use a dict in this way the `value`
parameter should be `None`.
- For a DataFrame a dict can specify that different values
should be replaced in different columns. For example,
``{'a': 1, 'b': 'z'}`` looks for the value 1 in column 'a'
and the value 'z' in column 'b' and replaces these values
with whatever is specified in `value`. The `value` parameter
should not be ``None`` in this case. You can treat this as a
special case of passing two lists except that you are
specifying the column to search in.
- For a DataFrame nested dictionaries, e.g.,
``{'a': {'b': np.nan}}``, are read as follows: look in column
'a' for the value 'b' and replace it with NaN. The `value`
parameter should be ``None`` to use a nested dict in this
way. You can nest regular expressions as well. Note that
column names (the top-level dictionary keys in a nested
dictionary) **cannot** be regular expressions.
* None:
- This means that the `regex` argument must be a string,
compiled regular expression, or list, dict, ndarray or
Series of such elements. If `value` is also ``None`` then
this **must** be a nested dictionary or Series.
See the examples section for examples of each of these.
value : scalar, dict, list, str, regex, default None
Value to replace any values matching `to_replace` with.
For a DataFrame a dict of values can be used to specify which
value to use for each column (columns not in the dict will not be
filled). Regular expressions, strings and lists or dicts of such
objects are also allowed.
inplace : bool, default False
If True, in place. Note: this will modify any
other views on this object (e.g. a column from a DataFrame).
Returns the caller if this is True.
limit : int, default None
Maximum size gap to forward or backward fill.
regex : bool or same types as `to_replace`, default False
Whether to interpret `to_replace` and/or `value` as regular
expressions. If this is ``True`` then `to_replace` *must* be a
string. Alternatively, this could be a regular expression or a
list, dict, or array of regular expressions in which case
`to_replace` must be ``None``.
method : {'pad', 'ffill', 'bfill', `None`}
The method to use when for replacement, when `to_replace` is a
scalar, list or tuple and `value` is ``None``.
.. versionchanged:: 0.23.0
Added to DataFrame.
Returns
-------
%(klass)s
Object after replacement.
Raises
------
AssertionError
* If `regex` is not a ``bool`` and `to_replace` is not
``None``.
TypeError
* If `to_replace` is a ``dict`` and `value` is not a ``list``,
``dict``, ``ndarray``, or ``Series``
* If `to_replace` is ``None`` and `regex` is not compilable
into a regular expression or is a list, dict, ndarray, or
Series.
* When replacing multiple ``bool`` or ``datetime64`` objects and
the arguments to `to_replace` does not match the type of the
value being replaced
ValueError
* If a ``list`` or an ``ndarray`` is passed to `to_replace` and
`value` but they are not the same length.
See Also
--------
%(klass)s.fillna : Fill NA values.
%(klass)s.where : Replace values based on boolean condition.
Series.str.replace : Simple string replacement.
Notes
-----
* Regex substitution is performed under the hood with ``re.sub``. The
rules for substitution for ``re.sub`` are the same.
* Regular expressions will only substitute on strings, meaning you
cannot provide, for example, a regular expression matching floating
point numbers and expect the columns in your frame that have a
numeric dtype to be matched. However, if those floating point
numbers *are* strings, then you can do this.
* This method has *a lot* of options. You are encouraged to experiment
and play with this method to gain intuition about how it works.
* When dict is used as the `to_replace` value, it is like
key(s) in the dict are the to_replace part and
value(s) in the dict are the value parameter.
Examples
--------
**Scalar `to_replace` and `value`**
>>> s = pd.Series([0, 1, 2, 3, 4])
>>> s.replace(0, 5)
0 5
1 1
2 2
3 3
4 4
dtype: int64
>>> df = pd.DataFrame({'A': [0, 1, 2, 3, 4],
... 'B': [5, 6, 7, 8, 9],
... 'C': ['a', 'b', 'c', 'd', 'e']})
>>> df.replace(0, 5)
A B C
0 5 5 a
1 1 6 b
2 2 7 c
3 3 8 d
4 4 9 e
**List-like `to_replace`**
>>> df.replace([0, 1, 2, 3], 4)
A B C
0 4 5 a
1 4 6 b
2 4 7 c
3 4 8 d
4 4 9 e
>>> df.replace([0, 1, 2, 3], [4, 3, 2, 1])
A B C
0 4 5 a
1 3 6 b
2 2 7 c
3 1 8 d
4 4 9 e
>>> s.replace([1, 2], method='bfill')
0 0
1 3
2 3
3 3
4 4
dtype: int64
**dict-like `to_replace`**
>>> df.replace({0: 10, 1: 100})
A B C
0 10 5 a
1 100 6 b
2 2 7 c
3 3 8 d
4 4 9 e
>>> df.replace({'A': 0, 'B': 5}, 100)
A B C
0 100 100 a
1 1 6 b
2 2 7 c
3 3 8 d
4 4 9 e
>>> df.replace({'A': {0: 100, 4: 400}})
A B C
0 100 5 a
1 1 6 b
2 2 7 c
3 3 8 d
4 400 9 e
**Regular expression `to_replace`**
>>> df = pd.DataFrame({'A': ['bat', 'foo', 'bait'],
... 'B': ['abc', 'bar', 'xyz']})
>>> df.replace(to_replace=r'^ba.$', value='new', regex=True)
A B
0 new abc
1 foo new
2 bait xyz
>>> df.replace({'A': r'^ba.$'}, {'A': 'new'}, regex=True)
A B
0 new abc
1 foo bar
2 bait xyz
>>> df.replace(regex=r'^ba.$', value='new')
A B
0 new abc
1 foo new
2 bait xyz
>>> df.replace(regex={r'^ba.$': 'new', 'foo': 'xyz'})
A B
0 new abc
1 xyz new
2 bait xyz
>>> df.replace(regex=[r'^ba.$', 'foo'], value='new')
A B
0 new abc
1 new new
2 bait xyz
Note that when replacing multiple ``bool`` or ``datetime64`` objects,
the data types in the `to_replace` parameter must match the data
type of the value being replaced:
>>> df = pd.DataFrame({'A': [True, False, True],
... 'B': [False, True, False]})
>>> df.replace({'a string': 'new value', True: False}) # raises
Traceback (most recent call last):
...
TypeError: Cannot compare types 'ndarray(dtype=bool)' and 'str'
This raises a ``TypeError`` because one of the ``dict`` keys is not of
the correct type for replacement.
Compare the behavior of ``s.replace({'a': None})`` and
``s.replace('a', None)`` to understand the peculiarities
of the `to_replace` parameter:
>>> s = pd.Series([10, 'a', 'a', 'b', 'a'])
When one uses a dict as the `to_replace` value, it is like the
value(s) in the dict are equal to the `value` parameter.
``s.replace({'a': None})`` is equivalent to
``s.replace(to_replace={'a': None}, value=None, method=None)``:
>>> s.replace({'a': None})
0 10
1 None
2 None
3 b
4 None
dtype: object
When ``value=None`` and `to_replace` is a scalar, list or
tuple, `replace` uses the method parameter (default 'pad') to do the
replacement. So this is why the 'a' values are being replaced by 10
in rows 1 and 2 and 'b' in row 4 in this case.
The command ``s.replace('a', None)`` is actually equivalent to
``s.replace(to_replace='a', value=None, method='pad')``:
>>> s.replace('a', None)
0 10
1 10
2 10
3 b
4 b
dtype: object
"""
@Appender(_shared_docs["replace"] % _shared_doc_kwargs)
def replace(
self,
to_replace=None,
value=None,
inplace=False,
limit=None,
regex=False,
method="pad",
):
inplace = validate_bool_kwarg(inplace, "inplace")
if not is_bool(regex) and to_replace is not None:
raise AssertionError("'to_replace' must be 'None' if 'regex' is not a bool")
self._consolidate_inplace()
if value is None:
# passing a single value that is scalar like
# when value is None (GH5319), for compat
if not is_dict_like(to_replace) and not is_dict_like(regex):
to_replace = [to_replace]
if isinstance(to_replace, (tuple, list)):
if isinstance(self, ABCDataFrame):
return self.apply(
_single_replace, args=(to_replace, method, inplace, limit)
)
return _single_replace(self, to_replace, method, inplace, limit)
if not is_dict_like(to_replace):
if not is_dict_like(regex):
raise TypeError(
'If "to_replace" and "value" are both None '
'and "to_replace" is not a list, then '
"regex must be a mapping"
)
to_replace = regex
regex = True
items = list(to_replace.items())
keys, values = zip(*items) if items else ([], [])
are_mappings = [is_dict_like(v) for v in values]
if any(are_mappings):
if not all(are_mappings):
raise TypeError(
"If a nested mapping is passed, all values "
"of the top level mapping must be mappings"
)
# passed a nested dict/Series
to_rep_dict = {}
value_dict = {}
for k, v in items:
keys, values = list(zip(*v.items())) or ([], [])
to_rep_dict[k] = list(keys)
value_dict[k] = list(values)
to_replace, value = to_rep_dict, value_dict
else:
to_replace, value = keys, values
return self.replace(
to_replace, value, inplace=inplace, limit=limit, regex=regex
)
else:
# need a non-zero len on all axes
if not self.size:
return self
new_data = self._data
if is_dict_like(to_replace):
if is_dict_like(value): # {'A' : NA} -> {'A' : 0}
res = self if inplace else self.copy()
for c, src in to_replace.items():
if c in value and c in self:
# object conversion is handled in
# series.replace which is called recursively
res[c] = res[c].replace(
to_replace=src,
value=value[c],
inplace=False,
regex=regex,
)
return None if inplace else res
# {'A': NA} -> 0
elif not is_list_like(value):
keys = [(k, src) for k, src in to_replace.items() if k in self]
keys_len = len(keys) - 1
for i, (k, src) in enumerate(keys):
convert = i == keys_len
new_data = new_data.replace(
to_replace=src,
value=value,
filter=[k],
inplace=inplace,
regex=regex,
convert=convert,
)
else:
raise TypeError("value argument must be scalar, dict, or Series")
elif is_list_like(to_replace): # [NA, ''] -> [0, 'missing']
if is_list_like(value):
if len(to_replace) != len(value):
raise ValueError(
f"Replacement lists must match in length. "
f"Expecting {len(to_replace)} got {len(value)} "
)
new_data = self._data.replace_list(
src_list=to_replace,
dest_list=value,
inplace=inplace,
regex=regex,
)
else: # [NA, ''] -> 0
new_data = self._data.replace(
to_replace=to_replace, value=value, inplace=inplace, regex=regex
)
elif to_replace is None:
if not (
is_re_compilable(regex)
or is_list_like(regex)
or is_dict_like(regex)
):
raise TypeError(
f"'regex' must be a string or a compiled regular expression "
f"or a list or dict of strings or regular expressions, "
f"you passed a {repr(type(regex).__name__)}"
)
return self.replace(
regex, value, inplace=inplace, limit=limit, regex=True
)
else:
# dest iterable dict-like
if is_dict_like(value): # NA -> {'A' : 0, 'B' : -1}
new_data = self._data
for k, v in value.items():
if k in self:
new_data = new_data.replace(
to_replace=to_replace,
value=v,
filter=[k],
inplace=inplace,
regex=regex,
)
elif not is_list_like(value): # NA -> 0
new_data = self._data.replace(
to_replace=to_replace, value=value, inplace=inplace, regex=regex
)
else:
raise TypeError(
f'Invalid "to_replace" type: {repr(type(to_replace).__name__)}'
)
if inplace:
self._update_inplace(new_data)
else:
return self._constructor(new_data).__finalize__(self)
_shared_docs[
"interpolate"
] = """
Please note that only ``method='linear'`` is supported for
DataFrame/Series with a MultiIndex.
Parameters
----------
method : str, default 'linear'
Interpolation technique to use. One of:
* 'linear': Ignore the index and treat the values as equally
spaced. This is the only method supported on MultiIndexes.
* 'time': Works on daily and higher resolution data to interpolate
given length of interval.
* 'index', 'values': use the actual numerical values of the index.
* 'pad': Fill in NaNs using existing values.
* 'nearest', 'zero', 'slinear', 'quadratic', 'cubic', 'spline',
'barycentric', 'polynomial': Passed to
`scipy.interpolate.interp1d`. These methods use the numerical
values of the index. Both 'polynomial' and 'spline' require that
you also specify an `order` (int), e.g.
``df.interpolate(method='polynomial', order=5)``.
* 'krogh', 'piecewise_polynomial', 'spline', 'pchip', 'akima':
Wrappers around the SciPy interpolation methods of similar
names. See `Notes`.
* 'from_derivatives': Refers to
`scipy.interpolate.BPoly.from_derivatives` which
replaces 'piecewise_polynomial' interpolation method in
scipy 0.18.
axis : {0 or 'index', 1 or 'columns', None}, default None
Axis to interpolate along.
limit : int, optional
Maximum number of consecutive NaNs to fill. Must be greater than
0.
inplace : bool, default False
Update the data in place if possible.
limit_direction : {'forward', 'backward', 'both'}, default 'forward'
If limit is specified, consecutive NaNs will be filled in this
direction.
limit_area : {`None`, 'inside', 'outside'}, default None
If limit is specified, consecutive NaNs will be filled with this
restriction.
* ``None``: No fill restriction.
* 'inside': Only fill NaNs surrounded by valid values
(interpolate).
* 'outside': Only fill NaNs outside valid values (extrapolate).
.. versionadded:: 0.23.0
downcast : optional, 'infer' or None, defaults to None
Downcast dtypes if possible.
**kwargs
Keyword arguments to pass on to the interpolating function.
Returns
-------
Series or DataFrame
Returns the same object type as the caller, interpolated at
some or all ``NaN`` values.
See Also
--------
fillna : Fill missing values using different methods.
scipy.interpolate.Akima1DInterpolator : Piecewise cubic polynomials
(Akima interpolator).
scipy.interpolate.BPoly.from_derivatives : Piecewise polynomial in the
Bernstein basis.
scipy.interpolate.interp1d : Interpolate a 1-D function.
scipy.interpolate.KroghInterpolator : Interpolate polynomial (Krogh
interpolator).
scipy.interpolate.PchipInterpolator : PCHIP 1-d monotonic cubic
interpolation.
scipy.interpolate.CubicSpline : Cubic spline data interpolator.
Notes
-----
The 'krogh', 'piecewise_polynomial', 'spline', 'pchip' and 'akima'
methods are wrappers around the respective SciPy implementations of
similar names. These use the actual numerical values of the index.
For more information on their behavior, see the
`SciPy documentation
<https://docs.scipy.org/doc/scipy/reference/interpolate.html#univariate-interpolation>`__
and `SciPy tutorial
<https://docs.scipy.org/doc/scipy/reference/tutorial/interpolate.html>`__.
Examples
--------
Filling in ``NaN`` in a :class:`~pandas.Series` via linear
interpolation.
>>> s = pd.Series([0, 1, np.nan, 3])
>>> s
0 0.0
1 1.0
2 NaN
3 3.0
dtype: float64
>>> s.interpolate()
0 0.0
1 1.0
2 2.0
3 3.0
dtype: float64
Filling in ``NaN`` in a Series by padding, but filling at most two
consecutive ``NaN`` at a time.
>>> s = pd.Series([np.nan, "single_one", np.nan,
... "fill_two_more", np.nan, np.nan, np.nan,
... 4.71, np.nan])
>>> s
0 NaN
1 single_one
2 NaN
3 fill_two_more
4 NaN
5 NaN
6 NaN
7 4.71
8 NaN
dtype: object
>>> s.interpolate(method='pad', limit=2)
0 NaN
1 single_one
2 single_one
3 fill_two_more
4 fill_two_more
5 fill_two_more
6 NaN
7 4.71
8 4.71
dtype: object
Filling in ``NaN`` in a Series via polynomial interpolation or splines:
Both 'polynomial' and 'spline' methods require that you also specify
an ``order`` (int).
>>> s = pd.Series([0, 2, np.nan, 8])
>>> s.interpolate(method='polynomial', order=2)
0 0.000000
1 2.000000
2 4.666667
3 8.000000
dtype: float64
Fill the DataFrame forward (that is, going down) along each column
using linear interpolation.
Note how the last entry in column 'a' is interpolated differently,
because there is no entry after it to use for interpolation.
Note how the first entry in column 'b' remains ``NaN``, because there
is no entry before it to use for interpolation.
>>> df = pd.DataFrame([(0.0, np.nan, -1.0, 1.0),
... (np.nan, 2.0, np.nan, np.nan),
... (2.0, 3.0, np.nan, 9.0),
... (np.nan, 4.0, -4.0, 16.0)],
... columns=list('abcd'))
>>> df
a b c d
0 0.0 NaN -1.0 1.0
1 NaN 2.0 NaN NaN
2 2.0 3.0 NaN 9.0
3 NaN 4.0 -4.0 16.0
>>> df.interpolate(method='linear', limit_direction='forward', axis=0)
a b c d
0 0.0 NaN -1.0 1.0
1 1.0 2.0 -2.0 5.0
2 2.0 3.0 -3.0 9.0
3 2.0 4.0 -4.0 16.0
Using polynomial interpolation.
>>> df['d'].interpolate(method='polynomial', order=2)
0 1.0
1 4.0
2 9.0
3 16.0
Name: d, dtype: float64
"""
@Appender(_shared_docs["interpolate"] % _shared_doc_kwargs)
def interpolate(
self,
method="linear",
axis=0,
limit=None,
inplace=False,
limit_direction="forward",
limit_area=None,
downcast=None,
**kwargs,
):
"""
Interpolate values according to different methods.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
axis = self._get_axis_number(axis)
if axis == 0:
ax = self._info_axis_name
_maybe_transposed_self = self
elif axis == 1:
_maybe_transposed_self = self.T
ax = 1
ax = _maybe_transposed_self._get_axis_number(ax)
if _maybe_transposed_self.ndim == 2:
alt_ax = 1 - ax
else:
alt_ax = ax
if isinstance(_maybe_transposed_self.index, MultiIndex) and method != "linear":
raise ValueError(
"Only `method=linear` interpolation is supported on MultiIndexes."
)
if _maybe_transposed_self._data.get_dtype_counts().get("object") == len(
_maybe_transposed_self.T
):
raise TypeError(
"Cannot interpolate with all object-dtype columns "
"in the DataFrame. Try setting at least one "
"column to a numeric dtype."
)
# create/use the index
if method == "linear":
# prior default
index = np.arange(len(_maybe_transposed_self._get_axis(alt_ax)))
else:
index = _maybe_transposed_self._get_axis(alt_ax)
methods = {"index", "values", "nearest", "time"}
is_numeric_or_datetime = (
is_numeric_dtype(index)
or is_datetime64_any_dtype(index)
or is_timedelta64_dtype(index)
)
if method not in methods and not is_numeric_or_datetime:
raise ValueError(
"Index column must be numeric or datetime type when "
f"using {method} method other than linear. "
"Try setting a numeric or datetime index column before "
"interpolating."
)
if isna(index).any():
raise NotImplementedError(
"Interpolation with NaNs in the index "
"has not been implemented. Try filling "
"those NaNs before interpolating."
)
data = _maybe_transposed_self._data
new_data = data.interpolate(
method=method,
axis=ax,
index=index,
values=_maybe_transposed_self,
limit=limit,
limit_direction=limit_direction,
limit_area=limit_area,
inplace=inplace,
downcast=downcast,
**kwargs,
)
if inplace:
if axis == 1:
new_data = self._constructor(new_data).T._data
self._update_inplace(new_data)
else:
res = self._constructor(new_data).__finalize__(self)
if axis == 1:
res = res.T
return res
# ----------------------------------------------------------------------
# Timeseries methods Methods
def asof(self, where, subset=None):
"""
Return the last row(s) without any NaNs before `where`.
The last row (for each element in `where`, if list) without any
NaN is taken.
In case of a :class:`~pandas.DataFrame`, the last row without NaN
considering only the subset of columns (if not `None`)
If there is no good value, NaN is returned for a Series or
a Series of NaN values for a DataFrame
Parameters
----------
where : date or array-like of dates
Date(s) before which the last row(s) are returned.
subset : str or array-like of str, default `None`
For DataFrame, if not `None`, only use these columns to
check for NaNs.
Returns
-------
scalar, Series, or DataFrame
The return can be:
* scalar : when `self` is a Series and `where` is a scalar
* Series: when `self` is a Series and `where` is an array-like,
or when `self` is a DataFrame and `where` is a scalar
* DataFrame : when `self` is a DataFrame and `where` is an
array-like
Return scalar, Series, or DataFrame.
See Also
--------
merge_asof : Perform an asof merge. Similar to left join.
Notes
-----
Dates are assumed to be sorted. Raises if this is not the case.
Examples
--------
A Series and a scalar `where`.
>>> s = pd.Series([1, 2, np.nan, 4], index=[10, 20, 30, 40])
>>> s
10 1.0
20 2.0
30 NaN
40 4.0
dtype: float64
>>> s.asof(20)
2.0
For a sequence `where`, a Series is returned. The first value is
NaN, because the first element of `where` is before the first
index value.
>>> s.asof([5, 20])
5 NaN
20 2.0
dtype: float64
Missing values are not considered. The following is ``2.0``, not
NaN, even though NaN is at the index location for ``30``.
>>> s.asof(30)
2.0
Take all columns into consideration
>>> df = pd.DataFrame({'a': [10, 20, 30, 40, 50],
... 'b': [None, None, None, None, 500]},
... index=pd.DatetimeIndex(['2018-02-27 09:01:00',
... '2018-02-27 09:02:00',
... '2018-02-27 09:03:00',
... '2018-02-27 09:04:00',
... '2018-02-27 09:05:00']))
>>> df.asof(pd.DatetimeIndex(['2018-02-27 09:03:30',
... '2018-02-27 09:04:30']))
a b
2018-02-27 09:03:30 NaN NaN
2018-02-27 09:04:30 NaN NaN
Take a single column into consideration
>>> df.asof(pd.DatetimeIndex(['2018-02-27 09:03:30',
... '2018-02-27 09:04:30']),
... subset=['a'])
a b
2018-02-27 09:03:30 30.0 NaN
2018-02-27 09:04:30 40.0 NaN
"""
if isinstance(where, str):
where = Timestamp(where)
if not self.index.is_monotonic:
raise ValueError("asof requires a sorted index")
is_series = isinstance(self, ABCSeries)
if is_series:
if subset is not None:
raise ValueError("subset is not valid for Series")
else:
if subset is None:
subset = self.columns
if not is_list_like(subset):
subset = [subset]
is_list = is_list_like(where)
if not is_list:
start = self.index[0]
if isinstance(self.index, PeriodIndex):
where = Period(where, freq=self.index.freq)
if where < start:
if not is_series:
from pandas import Series
return Series(index=self.columns, name=where, dtype=np.float64)
return np.nan
# It's always much faster to use a *while* loop here for
# Series than pre-computing all the NAs. However a
# *while* loop is extremely expensive for DataFrame
# so we later pre-compute all the NAs and use the same
# code path whether *where* is a scalar or list.
# See PR: https://github.com/pandas-dev/pandas/pull/14476
if is_series:
loc = self.index.searchsorted(where, side="right")
if loc > 0:
loc -= 1
values = self._values
while loc > 0 and isna(values[loc]):
loc -= 1
return values[loc]
if not isinstance(where, Index):
where = Index(where) if is_list else Index([where])
nulls = self.isna() if is_series else self[subset].isna().any(1)
if nulls.all():
if is_series:
return self._constructor(np.nan, index=where, name=self.name)
elif is_list:
from pandas import DataFrame
return DataFrame(np.nan, index=where, columns=self.columns)
else:
from pandas import Series
return Series(np.nan, index=self.columns, name=where[0])
locs = self.index.asof_locs(where, ~(nulls.values))
# mask the missing
missing = locs == -1
data = self.take(locs)
data.index = where
data.loc[missing] = np.nan
return data if is_list else data.iloc[-1]
# ----------------------------------------------------------------------
# Action Methods
_shared_docs[
"isna"
] = """
Detect missing values.
Return a boolean same-sized object indicating if the values are NA.
NA values, such as None or :attr:`numpy.NaN`, gets mapped to True
values.
Everything else gets mapped to False values. Characters such as empty
strings ``''`` or :attr:`numpy.inf` are not considered NA values
(unless you set ``pandas.options.mode.use_inf_as_na = True``).
Returns
-------
%(klass)s
Mask of bool values for each element in %(klass)s that
indicates whether an element is not an NA value.
See Also
--------
%(klass)s.isnull : Alias of isna.
%(klass)s.notna : Boolean inverse of isna.
%(klass)s.dropna : Omit axes labels with missing values.
isna : Top-level isna.
Examples
--------
Show which entries in a DataFrame are NA.
>>> df = pd.DataFrame({'age': [5, 6, np.NaN],
... 'born': [pd.NaT, pd.Timestamp('1939-05-27'),
... pd.Timestamp('1940-04-25')],
... 'name': ['Alfred', 'Batman', ''],
... 'toy': [None, 'Batmobile', 'Joker']})
>>> df
age born name toy
0 5.0 NaT Alfred None
1 6.0 1939-05-27 Batman Batmobile
2 NaN 1940-04-25 Joker
>>> df.isna()
age born name toy
0 False True False True
1 False False False False
2 True False False False
Show which entries in a Series are NA.
>>> ser = pd.Series([5, 6, np.NaN])
>>> ser
0 5.0
1 6.0
2 NaN
dtype: float64
>>> ser.isna()
0 False
1 False
2 True
dtype: bool
"""
@Appender(_shared_docs["isna"] % _shared_doc_kwargs)
def isna(self: FrameOrSeries) -> FrameOrSeries:
return isna(self).__finalize__(self)
@Appender(_shared_docs["isna"] % _shared_doc_kwargs)
def isnull(self: FrameOrSeries) -> FrameOrSeries:
return isna(self).__finalize__(self)
_shared_docs[
"notna"
] = """
Detect existing (non-missing) values.
Return a boolean same-sized object indicating if the values are not NA.
Non-missing values get mapped to True. Characters such as empty
strings ``''`` or :attr:`numpy.inf` are not considered NA values
(unless you set ``pandas.options.mode.use_inf_as_na = True``).
NA values, such as None or :attr:`numpy.NaN`, get mapped to False
values.
Returns
-------
%(klass)s
Mask of bool values for each element in %(klass)s that
indicates whether an element is not an NA value.
See Also
--------
%(klass)s.notnull : Alias of notna.
%(klass)s.isna : Boolean inverse of notna.
%(klass)s.dropna : Omit axes labels with missing values.
notna : Top-level notna.
Examples
--------
Show which entries in a DataFrame are not NA.
>>> df = pd.DataFrame({'age': [5, 6, np.NaN],
... 'born': [pd.NaT, pd.Timestamp('1939-05-27'),
... pd.Timestamp('1940-04-25')],
... 'name': ['Alfred', 'Batman', ''],
... 'toy': [None, 'Batmobile', 'Joker']})
>>> df
age born name toy
0 5.0 NaT Alfred None
1 6.0 1939-05-27 Batman Batmobile
2 NaN 1940-04-25 Joker
>>> df.notna()
age born name toy
0 True False True False
1 True True True True
2 False True True True
Show which entries in a Series are not NA.
>>> ser = pd.Series([5, 6, np.NaN])
>>> ser
0 5.0
1 6.0
2 NaN
dtype: float64
>>> ser.notna()
0 True
1 True
2 False
dtype: bool
"""
@Appender(_shared_docs["notna"] % _shared_doc_kwargs)
def notna(self: FrameOrSeries) -> FrameOrSeries:
return notna(self).__finalize__(self)
@Appender(_shared_docs["notna"] % _shared_doc_kwargs)
def notnull(self: FrameOrSeries) -> FrameOrSeries:
return notna(self).__finalize__(self)
def _clip_with_scalar(self, lower, upper, inplace: bool_t = False):
if (lower is not None and np.any(isna(lower))) or (
upper is not None and np.any(isna(upper))
):
raise ValueError("Cannot use an NA value as a clip threshold")
result = self
mask = isna(self.values)
with np.errstate(all="ignore"):
if upper is not None:
subset = self.to_numpy() <= upper
result = result.where(subset, upper, axis=None, inplace=False)
if lower is not None:
subset = self.to_numpy() >= lower
result = result.where(subset, lower, axis=None, inplace=False)
if np.any(mask):
result[mask] = np.nan
if inplace:
self._update_inplace(result)
else:
return result
def _clip_with_one_bound(self, threshold, method, axis, inplace):
if axis is not None:
axis = self._get_axis_number(axis)
# method is self.le for upper bound and self.ge for lower bound
if is_scalar(threshold) and is_number(threshold):
if method.__name__ == "le":
return self._clip_with_scalar(None, threshold, inplace=inplace)
return self._clip_with_scalar(threshold, None, inplace=inplace)
subset = method(threshold, axis=axis) | isna(self)
# GH #15390
# In order for where method to work, the threshold must
# be transformed to NDFrame from other array like structure.
if (not isinstance(threshold, ABCSeries)) and is_list_like(threshold):
if isinstance(self, ABCSeries):
threshold = self._constructor(threshold, index=self.index)
else:
threshold = _align_method_FRAME(self, threshold, axis, flex=None)[1]
return self.where(subset, threshold, axis=axis, inplace=inplace)
def clip(
self: FrameOrSeries,
lower=None,
upper=None,
axis=None,
inplace: bool_t = False,
*args,
**kwargs,
) -> FrameOrSeries:
"""
Trim values at input threshold(s).
Assigns values outside boundary to boundary values. Thresholds
can be singular values or array like, and in the latter case
the clipping is performed element-wise in the specified axis.
Parameters
----------
lower : float or array_like, default None
Minimum threshold value. All values below this
threshold will be set to it.
upper : float or array_like, default None
Maximum threshold value. All values above this
threshold will be set to it.
axis : int or str axis name, optional
Align object with lower and upper along the given axis.
inplace : bool, default False
Whether to perform the operation in place on the data.
.. versionadded:: 0.21.0
*args, **kwargs
Additional keywords have no effect but might be accepted
for compatibility with numpy.
Returns
-------
Series or DataFrame
Same type as calling object with the values outside the
clip boundaries replaced.
Examples
--------
>>> data = {'col_0': [9, -3, 0, -1, 5], 'col_1': [-2, -7, 6, 8, -5]}
>>> df = pd.DataFrame(data)
>>> df
col_0 col_1
0 9 -2
1 -3 -7
2 0 6
3 -1 8
4 5 -5
Clips per column using lower and upper thresholds:
>>> df.clip(-4, 6)
col_0 col_1
0 6 -2
1 -3 -4
2 0 6
3 -1 6
4 5 -4
Clips using specific lower and upper thresholds per column element:
>>> t = pd.Series([2, -4, -1, 6, 3])
>>> t
0 2
1 -4
2 -1
3 6
4 3
dtype: int64
>>> df.clip(t, t + 4, axis=0)
col_0 col_1
0 6 2
1 -3 -4
2 0 3
3 6 8
4 5 3
"""
inplace = validate_bool_kwarg(inplace, "inplace")
axis = nv.validate_clip_with_axis(axis, args, kwargs)
if axis is not None:
axis = self._get_axis_number(axis)
# GH 17276
# numpy doesn't like NaN as a clip value
# so ignore
# GH 19992
# numpy doesn't drop a list-like bound containing NaN
if not is_list_like(lower) and np.any(isna(lower)):
lower = None
if not is_list_like(upper) and np.any(isna(upper)):
upper = None
# GH 2747 (arguments were reversed)
if lower is not None and upper is not None:
if is_scalar(lower) and is_scalar(upper):
lower, upper = min(lower, upper), max(lower, upper)
# fast-path for scalars
if (lower is None or (is_scalar(lower) and is_number(lower))) and (
upper is None or (is_scalar(upper) and is_number(upper))
):
return self._clip_with_scalar(lower, upper, inplace=inplace)
result = self
if lower is not None:
result = result._clip_with_one_bound(
lower, method=self.ge, axis=axis, inplace=inplace
)
if upper is not None:
if inplace:
result = self
result = result._clip_with_one_bound(
upper, method=self.le, axis=axis, inplace=inplace
)
return result
_shared_docs[
"groupby"
] = """
Group %(klass)s using a mapper or by a Series of columns.
A groupby operation involves some combination of splitting the
object, applying a function, and combining the results. This can be
used to group large amounts of data and compute operations on these
groups.
Parameters
----------
by : mapping, function, label, or list of labels
Used to determine the groups for the groupby.
If ``by`` is a function, it's called on each value of the object's
index. If a dict or Series is passed, the Series or dict VALUES
will be used to determine the groups (the Series' values are first
aligned; see ``.align()`` method). If an ndarray is passed, the
values are used as-is determine the groups. A label or list of
labels may be passed to group by the columns in ``self``. Notice
that a tuple is interpreted as a (single) key.
axis : {0 or 'index', 1 or 'columns'}, default 0
Split along rows (0) or columns (1).
level : int, level name, or sequence of such, default None
If the axis is a MultiIndex (hierarchical), group by a particular
level or levels.
as_index : bool, default True
For aggregated output, return object with group labels as the
index. Only relevant for DataFrame input. as_index=False is
effectively "SQL-style" grouped output.
sort : bool, default True
Sort group keys. Get better performance by turning this off.
Note this does not influence the order of observations within each
group. Groupby preserves the order of rows within each group.
group_keys : bool, default True
When calling apply, add group keys to index to identify pieces.
squeeze : bool, default False
Reduce the dimensionality of the return type if possible,
otherwise return a consistent type.
observed : bool, default False
This only applies if any of the groupers are Categoricals.
If True: only show observed values for categorical groupers.
If False: show all values for categorical groupers.
.. versionadded:: 0.23.0
Returns
-------
%(klass)sGroupBy
Returns a groupby object that contains information about the groups.
See Also
--------
resample : Convenience method for frequency conversion and resampling
of time series.
Notes
-----
See the `user guide
<https://pandas.pydata.org/pandas-docs/stable/groupby.html>`_ for more.
"""
def asfreq(
self: FrameOrSeries,
freq,
method=None,
how: Optional[str] = None,
normalize: bool_t = False,
fill_value=None,
) -> FrameOrSeries:
"""
Convert TimeSeries to specified frequency.
Optionally provide filling method to pad/backfill missing values.
Returns the original data conformed to a new index with the specified
frequency. ``resample`` is more appropriate if an operation, such as
summarization, is necessary to represent the data at the new frequency.
Parameters
----------
freq : DateOffset or str
method : {'backfill'/'bfill', 'pad'/'ffill'}, default None
Method to use for filling holes in reindexed Series (note this
does not fill NaNs that already were present):
* 'pad' / 'ffill': propagate last valid observation forward to next
valid
* 'backfill' / 'bfill': use NEXT valid observation to fill.
how : {'start', 'end'}, default end
For PeriodIndex only (see PeriodIndex.asfreq).
normalize : bool, default False
Whether to reset output index to midnight.
fill_value : scalar, optional
Value to use for missing values, applied during upsampling (note
this does not fill NaNs that already were present).
Returns
-------
converted : same type as caller
See Also
--------
reindex
Notes
-----
To learn more about the frequency strings, please see `this link
<https://pandas.pydata.org/pandas-docs/stable/user_guide/timeseries.html#offset-aliases>`__.
Examples
--------
Start by creating a series with 4 one minute timestamps.
>>> index = pd.date_range('1/1/2000', periods=4, freq='T')
>>> series = pd.Series([0.0, None, 2.0, 3.0], index=index)
>>> df = pd.DataFrame({'s':series})
>>> df
s
2000-01-01 00:00:00 0.0
2000-01-01 00:01:00 NaN
2000-01-01 00:02:00 2.0
2000-01-01 00:03:00 3.0
Upsample the series into 30 second bins.
>>> df.asfreq(freq='30S')
s
2000-01-01 00:00:00 0.0
2000-01-01 00:00:30 NaN
2000-01-01 00:01:00 NaN
2000-01-01 00:01:30 NaN
2000-01-01 00:02:00 2.0
2000-01-01 00:02:30 NaN
2000-01-01 00:03:00 3.0
Upsample again, providing a ``fill value``.
>>> df.asfreq(freq='30S', fill_value=9.0)
s
2000-01-01 00:00:00 0.0
2000-01-01 00:00:30 9.0
2000-01-01 00:01:00 NaN
2000-01-01 00:01:30 9.0
2000-01-01 00:02:00 2.0
2000-01-01 00:02:30 9.0
2000-01-01 00:03:00 3.0
Upsample again, providing a ``method``.
>>> df.asfreq(freq='30S', method='bfill')
s
2000-01-01 00:00:00 0.0
2000-01-01 00:00:30 NaN
2000-01-01 00:01:00 NaN
2000-01-01 00:01:30 2.0
2000-01-01 00:02:00 2.0
2000-01-01 00:02:30 3.0
2000-01-01 00:03:00 3.0
"""
from pandas.core.resample import asfreq
return asfreq(
self,
freq,
method=method,
how=how,
normalize=normalize,
fill_value=fill_value,
)
def at_time(
self: FrameOrSeries, time, asof: bool_t = False, axis=None
) -> FrameOrSeries:
"""
Select values at particular time of day (e.g., 9:30AM).
Parameters
----------
time : datetime.time or str
axis : {0 or 'index', 1 or 'columns'}, default 0
.. versionadded:: 0.24.0
Returns
-------
Series or DataFrame
Raises
------
TypeError
If the index is not a :class:`DatetimeIndex`
See Also
--------
between_time : Select values between particular times of the day.
first : Select initial periods of time series based on a date offset.
last : Select final periods of time series based on a date offset.
DatetimeIndex.indexer_at_time : Get just the index locations for
values at particular time of the day.
Examples
--------
>>> i = pd.date_range('2018-04-09', periods=4, freq='12H')
>>> ts = pd.DataFrame({'A': [1, 2, 3, 4]}, index=i)
>>> ts
A
2018-04-09 00:00:00 1
2018-04-09 12:00:00 2
2018-04-10 00:00:00 3
2018-04-10 12:00:00 4
>>> ts.at_time('12:00')
A
2018-04-09 12:00:00 2
2018-04-10 12:00:00 4
"""
if axis is None:
axis = self._stat_axis_number
axis = self._get_axis_number(axis)
index = self._get_axis(axis)
try:
indexer = index.indexer_at_time(time, asof=asof)
except AttributeError:
raise TypeError("Index must be DatetimeIndex")
return self._take_with_is_copy(indexer, axis=axis)
def between_time(
self: FrameOrSeries,
start_time,
end_time,
include_start: bool_t = True,
include_end: bool_t = True,
axis=None,
) -> FrameOrSeries:
"""
Select values between particular times of the day (e.g., 9:00-9:30 AM).
By setting ``start_time`` to be later than ``end_time``,
you can get the times that are *not* between the two times.
Parameters
----------
start_time : datetime.time or str
Initial time as a time filter limit.
end_time : datetime.time or str
End time as a time filter limit.
include_start : bool, default True
Whether the start time needs to be included in the result.
include_end : bool, default True
Whether the end time needs to be included in the result.
axis : {0 or 'index', 1 or 'columns'}, default 0
Determine range time on index or columns value.
.. versionadded:: 0.24.0
Returns
-------
Series or DataFrame
Data from the original object filtered to the specified dates range.
Raises
------
TypeError
If the index is not a :class:`DatetimeIndex`
See Also
--------
at_time : Select values at a particular time of the day.
first : Select initial periods of time series based on a date offset.
last : Select final periods of time series based on a date offset.
DatetimeIndex.indexer_between_time : Get just the index locations for
values between particular times of the day.
Examples
--------
>>> i = pd.date_range('2018-04-09', periods=4, freq='1D20min')
>>> ts = pd.DataFrame({'A': [1, 2, 3, 4]}, index=i)
>>> ts
A
2018-04-09 00:00:00 1
2018-04-10 00:20:00 2
2018-04-11 00:40:00 3
2018-04-12 01:00:00 4
>>> ts.between_time('0:15', '0:45')
A
2018-04-10 00:20:00 2
2018-04-11 00:40:00 3
You get the times that are *not* between two times by setting
``start_time`` later than ``end_time``:
>>> ts.between_time('0:45', '0:15')
A
2018-04-09 00:00:00 1
2018-04-12 01:00:00 4
"""
if axis is None:
axis = self._stat_axis_number
axis = self._get_axis_number(axis)
index = self._get_axis(axis)
try:
indexer = index.indexer_between_time(
start_time,
end_time,
include_start=include_start,
include_end=include_end,
)
except AttributeError:
raise TypeError("Index must be DatetimeIndex")
return self._take_with_is_copy(indexer, axis=axis)
def resample(
self,
rule,
axis=0,
closed: Optional[str] = None,
label: Optional[str] = None,
convention: str = "start",
kind: Optional[str] = None,
loffset=None,
base: int = 0,
on=None,
level=None,
) -> "Resampler":
"""
Resample time-series data.
Convenience method for frequency conversion and resampling of time
series. Object must have a datetime-like index (`DatetimeIndex`,
`PeriodIndex`, or `TimedeltaIndex`), or pass datetime-like values
to the `on` or `level` keyword.
Parameters
----------
rule : DateOffset, Timedelta or str
The offset string or object representing target conversion.
axis : {0 or 'index', 1 or 'columns'}, default 0
Which axis to use for up- or down-sampling. For `Series` this
will default to 0, i.e. along the rows. Must be
`DatetimeIndex`, `TimedeltaIndex` or `PeriodIndex`.
closed : {'right', 'left'}, default None
Which side of bin interval is closed. The default is 'left'
for all frequency offsets except for 'M', 'A', 'Q', 'BM',
'BA', 'BQ', and 'W' which all have a default of 'right'.
label : {'right', 'left'}, default None
Which bin edge label to label bucket with. The default is 'left'
for all frequency offsets except for 'M', 'A', 'Q', 'BM',
'BA', 'BQ', and 'W' which all have a default of 'right'.
convention : {'start', 'end', 's', 'e'}, default 'start'
For `PeriodIndex` only, controls whether to use the start or
end of `rule`.
kind : {'timestamp', 'period'}, optional, default None
Pass 'timestamp' to convert the resulting index to a
`DateTimeIndex` or 'period' to convert it to a `PeriodIndex`.
By default the input representation is retained.
loffset : timedelta, default None
Adjust the resampled time labels.
base : int, default 0
For frequencies that evenly subdivide 1 day, the "origin" of the
aggregated intervals. For example, for '5min' frequency, base could
range from 0 through 4. Defaults to 0.
on : str, optional
For a DataFrame, column to use instead of index for resampling.
Column must be datetime-like.
level : str or int, optional
For a MultiIndex, level (name or number) to use for
resampling. `level` must be datetime-like.
Returns
-------
Resampler object
See Also
--------
groupby : Group by mapping, function, label, or list of labels.
Series.resample : Resample a Series.
DataFrame.resample: Resample a DataFrame.
Notes
-----
See the `user guide
<https://pandas.pydata.org/pandas-docs/stable/user_guide/timeseries.html#resampling>`_
for more.
To learn more about the offset strings, please see `this link
<https://pandas.pydata.org/pandas-docs/stable/user_guide/timeseries.html#dateoffset-objects>`__.
Examples
--------
Start by creating a series with 9 one minute timestamps.
>>> index = pd.date_range('1/1/2000', periods=9, freq='T')
>>> series = pd.Series(range(9), index=index)
>>> series
2000-01-01 00:00:00 0
2000-01-01 00:01:00 1
2000-01-01 00:02:00 2
2000-01-01 00:03:00 3
2000-01-01 00:04:00 4
2000-01-01 00:05:00 5
2000-01-01 00:06:00 6
2000-01-01 00:07:00 7
2000-01-01 00:08:00 8
Freq: T, dtype: int64
Downsample the series into 3 minute bins and sum the values
of the timestamps falling into a bin.
>>> series.resample('3T').sum()
2000-01-01 00:00:00 3
2000-01-01 00:03:00 12
2000-01-01 00:06:00 21
Freq: 3T, dtype: int64
Downsample the series into 3 minute bins as above, but label each
bin using the right edge instead of the left. Please note that the
value in the bucket used as the label is not included in the bucket,
which it labels. For example, in the original series the
bucket ``2000-01-01 00:03:00`` contains the value 3, but the summed
value in the resampled bucket with the label ``2000-01-01 00:03:00``
does not include 3 (if it did, the summed value would be 6, not 3).
To include this value close the right side of the bin interval as
illustrated in the example below this one.
>>> series.resample('3T', label='right').sum()
2000-01-01 00:03:00 3
2000-01-01 00:06:00 12
2000-01-01 00:09:00 21
Freq: 3T, dtype: int64
Downsample the series into 3 minute bins as above, but close the right
side of the bin interval.
>>> series.resample('3T', label='right', closed='right').sum()
2000-01-01 00:00:00 0
2000-01-01 00:03:00 6
2000-01-01 00:06:00 15
2000-01-01 00:09:00 15
Freq: 3T, dtype: int64
Upsample the series into 30 second bins.
>>> series.resample('30S').asfreq()[0:5] # Select first 5 rows
2000-01-01 00:00:00 0.0
2000-01-01 00:00:30 NaN
2000-01-01 00:01:00 1.0
2000-01-01 00:01:30 NaN
2000-01-01 00:02:00 2.0
Freq: 30S, dtype: float64
Upsample the series into 30 second bins and fill the ``NaN``
values using the ``pad`` method.
>>> series.resample('30S').pad()[0:5]
2000-01-01 00:00:00 0
2000-01-01 00:00:30 0
2000-01-01 00:01:00 1
2000-01-01 00:01:30 1
2000-01-01 00:02:00 2
Freq: 30S, dtype: int64
Upsample the series into 30 second bins and fill the
``NaN`` values using the ``bfill`` method.
>>> series.resample('30S').bfill()[0:5]
2000-01-01 00:00:00 0
2000-01-01 00:00:30 1
2000-01-01 00:01:00 1
2000-01-01 00:01:30 2
2000-01-01 00:02:00 2
Freq: 30S, dtype: int64
Pass a custom function via ``apply``
>>> def custom_resampler(array_like):
... return np.sum(array_like) + 5
...
>>> series.resample('3T').apply(custom_resampler)
2000-01-01 00:00:00 8
2000-01-01 00:03:00 17
2000-01-01 00:06:00 26
Freq: 3T, dtype: int64
For a Series with a PeriodIndex, the keyword `convention` can be
used to control whether to use the start or end of `rule`.
Resample a year by quarter using 'start' `convention`. Values are
assigned to the first quarter of the period.
>>> s = pd.Series([1, 2], index=pd.period_range('2012-01-01',
... freq='A',
... periods=2))
>>> s
2012 1
2013 2
Freq: A-DEC, dtype: int64
>>> s.resample('Q', convention='start').asfreq()
2012Q1 1.0
2012Q2 NaN
2012Q3 NaN
2012Q4 NaN
2013Q1 2.0
2013Q2 NaN
2013Q3 NaN
2013Q4 NaN
Freq: Q-DEC, dtype: float64
Resample quarters by month using 'end' `convention`. Values are
assigned to the last month of the period.
>>> q = pd.Series([1, 2, 3, 4], index=pd.period_range('2018-01-01',
... freq='Q',
... periods=4))
>>> q
2018Q1 1
2018Q2 2
2018Q3 3
2018Q4 4
Freq: Q-DEC, dtype: int64
>>> q.resample('M', convention='end').asfreq()
2018-03 1.0
2018-04 NaN
2018-05 NaN
2018-06 2.0
2018-07 NaN
2018-08 NaN
2018-09 3.0
2018-10 NaN
2018-11 NaN
2018-12 4.0
Freq: M, dtype: float64
For DataFrame objects, the keyword `on` can be used to specify the
column instead of the index for resampling.
>>> d = dict({'price': [10, 11, 9, 13, 14, 18, 17, 19],
... 'volume': [50, 60, 40, 100, 50, 100, 40, 50]})
>>> df = pd.DataFrame(d)
>>> df['week_starting'] = pd.date_range('01/01/2018',
... periods=8,
... freq='W')
>>> df
price volume week_starting
0 10 50 2018-01-07
1 11 60 2018-01-14
2 9 40 2018-01-21
3 13 100 2018-01-28
4 14 50 2018-02-04
5 18 100 2018-02-11
6 17 40 2018-02-18
7 19 50 2018-02-25
>>> df.resample('M', on='week_starting').mean()
price volume
week_starting
2018-01-31 10.75 62.5
2018-02-28 17.00 60.0
For a DataFrame with MultiIndex, the keyword `level` can be used to
specify on which level the resampling needs to take place.
>>> days = pd.date_range('1/1/2000', periods=4, freq='D')
>>> d2 = dict({'price': [10, 11, 9, 13, 14, 18, 17, 19],
... 'volume': [50, 60, 40, 100, 50, 100, 40, 50]})
>>> df2 = pd.DataFrame(d2,
... index=pd.MultiIndex.from_product([days,
... ['morning',
... 'afternoon']]
... ))
>>> df2
price volume
2000-01-01 morning 10 50
afternoon 11 60
2000-01-02 morning 9 40
afternoon 13 100
2000-01-03 morning 14 50
afternoon 18 100
2000-01-04 morning 17 40
afternoon 19 50
>>> df2.resample('D', level=0).sum()
price volume
2000-01-01 21 110
2000-01-02 22 140
2000-01-03 32 150
2000-01-04 36 90
"""
from pandas.core.resample import get_resampler
axis = self._get_axis_number(axis)
return get_resampler(
self,
freq=rule,
label=label,
closed=closed,
axis=axis,
kind=kind,
loffset=loffset,
convention=convention,
base=base,
key=on,
level=level,
)
def first(self: FrameOrSeries, offset) -> FrameOrSeries:
"""
Method to subset initial periods of time series data based on a date offset.
Parameters
----------
offset : str, DateOffset, dateutil.relativedelta
Returns
-------
subset : same type as caller
Raises
------
TypeError
If the index is not a :class:`DatetimeIndex`
See Also
--------
last : Select final periods of time series based on a date offset.
at_time : Select values at a particular time of the day.
between_time : Select values between particular times of the day.
Examples
--------
>>> i = pd.date_range('2018-04-09', periods=4, freq='2D')
>>> ts = pd.DataFrame({'A': [1,2,3,4]}, index=i)
>>> ts
A
2018-04-09 1
2018-04-11 2
2018-04-13 3
2018-04-15 4
Get the rows for the first 3 days:
>>> ts.first('3D')
A
2018-04-09 1
2018-04-11 2
Notice the data for 3 first calender days were returned, not the first
3 days observed in the dataset, and therefore data for 2018-04-13 was
not returned.
"""
if not isinstance(self.index, DatetimeIndex):
raise TypeError("'first' only supports a DatetimeIndex index")
if len(self.index) == 0:
return self
offset = to_offset(offset)
end_date = end = self.index[0] + offset
# Tick-like, e.g. 3 weeks
if not offset.is_anchored() and hasattr(offset, "_inc"):
if end_date in self.index:
end = self.index.searchsorted(end_date, side="left")
return self.iloc[:end]
return self.loc[:end]
def last(self: FrameOrSeries, offset) -> FrameOrSeries:
"""
Method to subset final periods of time series data based on a date offset.
Parameters
----------
offset : str, DateOffset, dateutil.relativedelta
Returns
-------
subset : same type as caller
Raises
------
TypeError
If the index is not a :class:`DatetimeIndex`
See Also
--------
first : Select initial periods of time series based on a date offset.
at_time : Select values at a particular time of the day.
between_time : Select values between particular times of the day.
Examples
--------
>>> i = pd.date_range('2018-04-09', periods=4, freq='2D')
>>> ts = pd.DataFrame({'A': [1, 2, 3, 4]}, index=i)
>>> ts
A
2018-04-09 1
2018-04-11 2
2018-04-13 3
2018-04-15 4
Get the rows for the last 3 days:
>>> ts.last('3D')
A
2018-04-13 3
2018-04-15 4
Notice the data for 3 last calender days were returned, not the last
3 observed days in the dataset, and therefore data for 2018-04-11 was
not returned.
"""
if not isinstance(self.index, DatetimeIndex):
raise TypeError("'last' only supports a DatetimeIndex index")
if len(self.index) == 0:
return self
offset = to_offset(offset)
start_date = self.index[-1] - offset
start = self.index.searchsorted(start_date, side="right")
return self.iloc[start:]
def rank(
self: FrameOrSeries,
axis=0,
method: str = "average",
numeric_only: Optional[bool_t] = None,
na_option: str = "keep",
ascending: bool_t = True,
pct: bool_t = False,
) -> FrameOrSeries:
"""
Compute numerical data ranks (1 through n) along axis.
By default, equal values are assigned a rank that is the average of the
ranks of those values.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
Index to direct ranking.
method : {'average', 'min', 'max', 'first', 'dense'}, default 'average'
How to rank the group of records that have the same value (i.e. ties):
* average: average rank of the group
* min: lowest rank in the group
* max: highest rank in the group
* first: ranks assigned in order they appear in the array
* dense: like 'min', but rank always increases by 1 between groups.
numeric_only : bool, optional
For DataFrame objects, rank only numeric columns if set to True.
na_option : {'keep', 'top', 'bottom'}, default 'keep'
How to rank NaN values:
* keep: assign NaN rank to NaN values
* top: assign smallest rank to NaN values if ascending
* bottom: assign highest rank to NaN values if ascending.
ascending : bool, default True
Whether or not the elements should be ranked in ascending order.
pct : bool, default False
Whether or not to display the returned rankings in percentile
form.
Returns
-------
same type as caller
Return a Series or DataFrame with data ranks as values.
See Also
--------
core.groupby.GroupBy.rank : Rank of values within each group.
Examples
--------
>>> df = pd.DataFrame(data={'Animal': ['cat', 'penguin', 'dog',
... 'spider', 'snake'],
... 'Number_legs': [4, 2, 4, 8, np.nan]})
>>> df
Animal Number_legs
0 cat 4.0
1 penguin 2.0
2 dog 4.0
3 spider 8.0
4 snake NaN
The following example shows how the method behaves with the above
parameters:
* default_rank: this is the default behaviour obtained without using
any parameter.
* max_rank: setting ``method = 'max'`` the records that have the
same values are ranked using the highest rank (e.g.: since 'cat'
and 'dog' are both in the 2nd and 3rd position, rank 3 is assigned.)
* NA_bottom: choosing ``na_option = 'bottom'``, if there are records
with NaN values they are placed at the bottom of the ranking.
* pct_rank: when setting ``pct = True``, the ranking is expressed as
percentile rank.
>>> df['default_rank'] = df['Number_legs'].rank()
>>> df['max_rank'] = df['Number_legs'].rank(method='max')
>>> df['NA_bottom'] = df['Number_legs'].rank(na_option='bottom')
>>> df['pct_rank'] = df['Number_legs'].rank(pct=True)
>>> df
Animal Number_legs default_rank max_rank NA_bottom pct_rank
0 cat 4.0 2.5 3.0 2.5 0.625
1 penguin 2.0 1.0 1.0 1.0 0.250
2 dog 4.0 2.5 3.0 2.5 0.625
3 spider 8.0 4.0 4.0 4.0 1.000
4 snake NaN NaN NaN 5.0 NaN
"""
axis = self._get_axis_number(axis)
if na_option not in {"keep", "top", "bottom"}:
msg = "na_option must be one of 'keep', 'top', or 'bottom'"
raise ValueError(msg)
def ranker(data):
ranks = algos.rank(
data.values,
axis=axis,
method=method,
ascending=ascending,
na_option=na_option,
pct=pct,
)
ranks = self._constructor(ranks, **data._construct_axes_dict())
return ranks.__finalize__(self)
# if numeric_only is None, and we can't get anything, we try with
# numeric_only=True
if numeric_only is None:
try:
return ranker(self)
except TypeError:
numeric_only = True
if numeric_only:
data = self._get_numeric_data()
else:
data = self
return ranker(data)
_shared_docs[
"align"
] = """
Align two objects on their axes with the specified join method.
Join method is specified for each axis Index.
Parameters
----------
other : DataFrame or Series
join : {'outer', 'inner', 'left', 'right'}, default 'outer'
axis : allowed axis of the other object, default None
Align on index (0), columns (1), or both (None).
level : int or level name, default None
Broadcast across a level, matching Index values on the
passed MultiIndex level.
copy : bool, default True
Always returns new objects. If copy=False and no reindexing is
required then original objects are returned.
fill_value : scalar, default np.NaN
Value to use for missing values. Defaults to NaN, but can be any
"compatible" value.
method : {'backfill', 'bfill', 'pad', 'ffill', None}, default None
Method to use for filling holes in reindexed Series:
- pad / ffill: propagate last valid observation forward to next valid.
- backfill / bfill: use NEXT valid observation to fill gap.
limit : int, default None
If method is specified, this is the maximum number of consecutive
NaN values to forward/backward fill. In other words, if there is
a gap with more than this number of consecutive NaNs, it will only
be partially filled. If method is not specified, this is the
maximum number of entries along the entire axis where NaNs will be
filled. Must be greater than 0 if not None.
fill_axis : %(axes_single_arg)s, default 0
Filling axis, method and limit.
broadcast_axis : %(axes_single_arg)s, default None
Broadcast values along this axis, if aligning two objects of
different dimensions.
Returns
-------
(left, right) : (%(klass)s, type of other)
Aligned objects.
"""
@Appender(_shared_docs["align"] % _shared_doc_kwargs)
def align(
self,
other,
join="outer",
axis=None,
level=None,
copy=True,
fill_value=None,
method=None,
limit=None,
fill_axis=0,
broadcast_axis=None,
):
method = missing.clean_fill_method(method)
if broadcast_axis == 1 and self.ndim != other.ndim:
if isinstance(self, ABCSeries):
# this means other is a DataFrame, and we need to broadcast
# self
cons = self._constructor_expanddim
df = cons(
{c: self for c in other.columns}, **other._construct_axes_dict()
)
return df._align_frame(
other,
join=join,
axis=axis,
level=level,
copy=copy,
fill_value=fill_value,
method=method,
limit=limit,
fill_axis=fill_axis,
)
elif isinstance(other, ABCSeries):
# this means self is a DataFrame, and we need to broadcast
# other
cons = other._constructor_expanddim
df = cons(
{c: other for c in self.columns}, **self._construct_axes_dict()
)
return self._align_frame(
df,
join=join,
axis=axis,
level=level,
copy=copy,
fill_value=fill_value,
method=method,
limit=limit,
fill_axis=fill_axis,
)
if axis is not None:
axis = self._get_axis_number(axis)
if isinstance(other, ABCDataFrame):
return self._align_frame(
other,
join=join,
axis=axis,
level=level,
copy=copy,
fill_value=fill_value,
method=method,
limit=limit,
fill_axis=fill_axis,
)
elif isinstance(other, ABCSeries):
return self._align_series(
other,
join=join,
axis=axis,
level=level,
copy=copy,
fill_value=fill_value,
method=method,
limit=limit,
fill_axis=fill_axis,
)
else: # pragma: no cover
raise TypeError(f"unsupported type: {type(other)}")
def _align_frame(
self,
other,
join="outer",
axis=None,
level=None,
copy: bool_t = True,
fill_value=None,
method=None,
limit=None,
fill_axis=0,
):
# defaults
join_index, join_columns = None, None
ilidx, iridx = None, None
clidx, cridx = None, None
is_series = isinstance(self, ABCSeries)
if axis is None or axis == 0:
if not self.index.equals(other.index):
join_index, ilidx, iridx = self.index.join(
other.index, how=join, level=level, return_indexers=True
)
if axis is None or axis == 1:
if not is_series and not self.columns.equals(other.columns):
join_columns, clidx, cridx = self.columns.join(
other.columns, how=join, level=level, return_indexers=True
)
if is_series:
reindexers = {0: [join_index, ilidx]}
else:
reindexers = {0: [join_index, ilidx], 1: [join_columns, clidx]}
left = self._reindex_with_indexers(
reindexers, copy=copy, fill_value=fill_value, allow_dups=True
)
# other must be always DataFrame
right = other._reindex_with_indexers(
{0: [join_index, iridx], 1: [join_columns, cridx]},
copy=copy,
fill_value=fill_value,
allow_dups=True,
)
if method is not None:
left = self._ensure_type(
left.fillna(method=method, axis=fill_axis, limit=limit)
)
right = right.fillna(method=method, axis=fill_axis, limit=limit)
# if DatetimeIndex have different tz, convert to UTC
if is_datetime64tz_dtype(left.index):
if left.index.tz != right.index.tz:
if join_index is not None:
left.index = join_index
right.index = join_index
return left.__finalize__(self), right.__finalize__(other)
def _align_series(
self,
other,
join="outer",
axis=None,
level=None,
copy: bool_t = True,
fill_value=None,
method=None,
limit=None,
fill_axis=0,
):
is_series = isinstance(self, ABCSeries)
# series/series compat, other must always be a Series
if is_series:
if axis:
raise ValueError("cannot align series to a series other than axis 0")
# equal
if self.index.equals(other.index):
join_index, lidx, ridx = None, None, None
else:
join_index, lidx, ridx = self.index.join(
other.index, how=join, level=level, return_indexers=True
)
left = self._reindex_indexer(join_index, lidx, copy)
right = other._reindex_indexer(join_index, ridx, copy)
else:
# one has > 1 ndim
fdata = self._data
if axis == 0:
join_index = self.index
lidx, ridx = None, None
if not self.index.equals(other.index):
join_index, lidx, ridx = self.index.join(
other.index, how=join, level=level, return_indexers=True
)
if lidx is not None:
fdata = fdata.reindex_indexer(join_index, lidx, axis=1)
elif axis == 1:
join_index = self.columns
lidx, ridx = None, None
if not self.columns.equals(other.index):
join_index, lidx, ridx = self.columns.join(
other.index, how=join, level=level, return_indexers=True
)
if lidx is not None:
fdata = fdata.reindex_indexer(join_index, lidx, axis=0)
else:
raise ValueError("Must specify axis=0 or 1")
if copy and fdata is self._data:
fdata = fdata.copy()
left = self._constructor(fdata)
if ridx is None:
right = other
else:
right = other.reindex(join_index, level=level)
# fill
fill_na = notna(fill_value) or (method is not None)
if fill_na:
left = left.fillna(fill_value, method=method, limit=limit, axis=fill_axis)
right = right.fillna(fill_value, method=method, limit=limit)
# if DatetimeIndex have different tz, convert to UTC
if is_series or (not is_series and axis == 0):
if is_datetime64tz_dtype(left.index):
if left.index.tz != right.index.tz:
if join_index is not None:
left.index = join_index
right.index = join_index
return left.__finalize__(self), right.__finalize__(other)
def _where(
self,
cond,
other=np.nan,
inplace=False,
axis=None,
level=None,
errors="raise",
try_cast=False,
):
"""
Equivalent to public method `where`, except that `other` is not
applied as a function even if callable. Used in __setitem__.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
# align the cond to same shape as myself
cond = com.apply_if_callable(cond, self)
if isinstance(cond, NDFrame):
cond, _ = cond.align(self, join="right", broadcast_axis=1)
else:
if not hasattr(cond, "shape"):
cond = np.asanyarray(cond)
if cond.shape != self.shape:
raise ValueError("Array conditional must be same shape as self")
cond = self._constructor(cond, **self._construct_axes_dict())
# make sure we are boolean
fill_value = bool(inplace)
cond = cond.fillna(fill_value)
msg = "Boolean array expected for the condition, not {dtype}"
if not isinstance(cond, ABCDataFrame):
# This is a single-dimensional object.
if not is_bool_dtype(cond):
raise ValueError(msg.format(dtype=cond.dtype))
elif not cond.empty:
for dt in cond.dtypes:
if not is_bool_dtype(dt):
raise ValueError(msg.format(dtype=dt))
cond = -cond if inplace else cond
# try to align with other
try_quick = True
if hasattr(other, "align"):
# align with me
if other.ndim <= self.ndim:
_, other = self.align(
other, join="left", axis=axis, level=level, fill_value=np.nan
)
# if we are NOT aligned, raise as we cannot where index
if axis is None and not all(
other._get_axis(i).equals(ax) for i, ax in enumerate(self.axes)
):
raise InvalidIndexError
# slice me out of the other
else:
raise NotImplementedError(
"cannot align with a higher dimensional NDFrame"
)
if isinstance(other, np.ndarray):
if other.shape != self.shape:
if self.ndim == 1:
icond = cond.values
# GH 2745 / GH 4192
# treat like a scalar
if len(other) == 1:
other = np.array(other[0])
# GH 3235
# match True cond to other
elif len(cond[icond]) == len(other):
# try to not change dtype at first (if try_quick)
if try_quick:
new_other = com.values_from_object(self)
new_other = new_other.copy()
new_other[icond] = other
other = new_other
else:
raise ValueError(
"Length of replacements must equal series length"
)
else:
raise ValueError(
"other must be the same shape as self when an ndarray"
)
# we are the same shape, so create an actual object for alignment
else:
other = self._constructor(other, **self._construct_axes_dict())
if axis is None:
axis = 0
if self.ndim == getattr(other, "ndim", 0):
align = True
else:
align = self._get_axis_number(axis) == 1
block_axis = self._get_block_manager_axis(axis)
if inplace:
# we may have different type blocks come out of putmask, so
# reconstruct the block manager
self._check_inplace_setting(other)
new_data = self._data.putmask(
mask=cond,
new=other,
align=align,
inplace=True,
axis=block_axis,
transpose=self._AXIS_REVERSED,
)
self._update_inplace(new_data)
else:
new_data = self._data.where(
other=other,
cond=cond,
align=align,
errors=errors,
try_cast=try_cast,
axis=block_axis,
)
return self._constructor(new_data).__finalize__(self)
_shared_docs[
"where"
] = """
Replace values where the condition is %(cond_rev)s.
Parameters
----------
cond : bool %(klass)s, array-like, or callable
Where `cond` is %(cond)s, keep the original value. Where
%(cond_rev)s, replace with corresponding value from `other`.
If `cond` is callable, it is computed on the %(klass)s and
should return boolean %(klass)s or array. The callable must
not change input %(klass)s (though pandas doesn't check it).
other : scalar, %(klass)s, or callable
Entries where `cond` is %(cond_rev)s are replaced with
corresponding value from `other`.
If other is callable, it is computed on the %(klass)s and
should return scalar or %(klass)s. The callable must not
change input %(klass)s (though pandas doesn't check it).
inplace : bool, default False
Whether to perform the operation in place on the data.
axis : int, default None
Alignment axis if needed.
level : int, default None
Alignment level if needed.
errors : str, {'raise', 'ignore'}, default 'raise'
Note that currently this parameter won't affect
the results and will always coerce to a suitable dtype.
- 'raise' : allow exceptions to be raised.
- 'ignore' : suppress exceptions. On error return original object.
try_cast : bool, default False
Try to cast the result back to the input type (if possible).
Returns
-------
Same type as caller
See Also
--------
:func:`DataFrame.%(name_other)s` : Return an object of same shape as
self.
Notes
-----
The %(name)s method is an application of the if-then idiom. For each
element in the calling DataFrame, if ``cond`` is ``%(cond)s`` the
element is used; otherwise the corresponding element from the DataFrame
``other`` is used.
The signature for :func:`DataFrame.where` differs from
:func:`numpy.where`. Roughly ``df1.where(m, df2)`` is equivalent to
``np.where(m, df1, df2)``.
For further details and examples see the ``%(name)s`` documentation in
:ref:`indexing <indexing.where_mask>`.
Examples
--------
>>> s = pd.Series(range(5))
>>> s.where(s > 0)
0 NaN
1 1.0
2 2.0
3 3.0
4 4.0
dtype: float64
>>> s.mask(s > 0)
0 0.0
1 NaN
2 NaN
3 NaN
4 NaN
dtype: float64
>>> s.where(s > 1, 10)
0 10
1 10
2 2
3 3
4 4
dtype: int64
>>> df = pd.DataFrame(np.arange(10).reshape(-1, 2), columns=['A', 'B'])
>>> df
A B
0 0 1
1 2 3
2 4 5
3 6 7
4 8 9
>>> m = df %% 3 == 0
>>> df.where(m, -df)
A B
0 0 -1
1 -2 3
2 -4 -5
3 6 -7
4 -8 9
>>> df.where(m, -df) == np.where(m, df, -df)
A B
0 True True
1 True True
2 True True
3 True True
4 True True
>>> df.where(m, -df) == df.mask(~m, -df)
A B
0 True True
1 True True
2 True True
3 True True
4 True True
"""
@Appender(
_shared_docs["where"]
% dict(
_shared_doc_kwargs,
cond="True",
cond_rev="False",
name="where",
name_other="mask",
)
)
def where(
self,
cond,
other=np.nan,
inplace=False,
axis=None,
level=None,
errors="raise",
try_cast=False,
):
other = com.apply_if_callable(other, self)
return self._where(
cond, other, inplace, axis, level, errors=errors, try_cast=try_cast
)
@Appender(
_shared_docs["where"]
% dict(
_shared_doc_kwargs,
cond="False",
cond_rev="True",
name="mask",
name_other="where",
)
)
def mask(
self,
cond,
other=np.nan,
inplace=False,
axis=None,
level=None,
errors="raise",
try_cast=False,
):
inplace = validate_bool_kwarg(inplace, "inplace")
cond = com.apply_if_callable(cond, self)
# see gh-21891
if not hasattr(cond, "__invert__"):
cond = np.array(cond)
return self.where(
~cond,
other=other,
inplace=inplace,
axis=axis,
level=level,
try_cast=try_cast,
errors=errors,
)
_shared_docs[
"shift"
] = """
Shift index by desired number of periods with an optional time `freq`.
When `freq` is not passed, shift the index without realigning the data.
If `freq` is passed (in this case, the index must be date or datetime,
or it will raise a `NotImplementedError`), the index will be
increased using the periods and the `freq`.
Parameters
----------
periods : int
Number of periods to shift. Can be positive or negative.
freq : DateOffset, tseries.offsets, timedelta, or str, optional
Offset to use from the tseries module or time rule (e.g. 'EOM').
If `freq` is specified then the index values are shifted but the
data is not realigned. That is, use `freq` if you would like to
extend the index when shifting and preserve the original data.
axis : {0 or 'index', 1 or 'columns', None}, default None
Shift direction.
fill_value : object, optional
The scalar value to use for newly introduced missing values.
the default depends on the dtype of `self`.
For numeric data, ``np.nan`` is used.
For datetime, timedelta, or period data, etc. :attr:`NaT` is used.
For extension dtypes, ``self.dtype.na_value`` is used.
.. versionchanged:: 0.24.0
Returns
-------
%(klass)s
Copy of input object, shifted.
See Also
--------
Index.shift : Shift values of Index.
DatetimeIndex.shift : Shift values of DatetimeIndex.
PeriodIndex.shift : Shift values of PeriodIndex.
tshift : Shift the time index, using the index's frequency if
available.
Examples
--------
>>> df = pd.DataFrame({'Col1': [10, 20, 15, 30, 45],
... 'Col2': [13, 23, 18, 33, 48],
... 'Col3': [17, 27, 22, 37, 52]})
>>> df.shift(periods=3)
Col1 Col2 Col3
0 NaN NaN NaN
1 NaN NaN NaN
2 NaN NaN NaN
3 10.0 13.0 17.0
4 20.0 23.0 27.0
>>> df.shift(periods=1, axis='columns')
Col1 Col2 Col3
0 NaN 10.0 13.0
1 NaN 20.0 23.0
2 NaN 15.0 18.0
3 NaN 30.0 33.0
4 NaN 45.0 48.0
>>> df.shift(periods=3, fill_value=0)
Col1 Col2 Col3
0 0 0 0
1 0 0 0
2 0 0 0
3 10 13 17
4 20 23 27
"""
@Appender(_shared_docs["shift"] % _shared_doc_kwargs)
def shift(
self: FrameOrSeries, periods=1, freq=None, axis=0, fill_value=None
) -> FrameOrSeries:
if periods == 0:
return self.copy()
block_axis = self._get_block_manager_axis(axis)
if freq is None:
new_data = self._data.shift(
periods=periods, axis=block_axis, fill_value=fill_value
)
else:
return self.tshift(periods, freq)
return self._constructor(new_data).__finalize__(self)
def slice_shift(self: FrameOrSeries, periods: int = 1, axis=0) -> FrameOrSeries:
"""
Equivalent to `shift` without copying data.
The shifted data will not include the dropped periods and the
shifted axis will be smaller than the original.
Parameters
----------
periods : int
Number of periods to move, can be positive or negative.
Returns
-------
shifted : same type as caller
Notes
-----
While the `slice_shift` is faster than `shift`, you may pay for it
later during alignment.
"""
if periods == 0:
return self
if periods > 0:
vslicer = slice(None, -periods)
islicer = slice(periods, None)
else:
vslicer = slice(-periods, None)
islicer = slice(None, periods)
new_obj = self._slice(vslicer, axis=axis)
shifted_axis = self._get_axis(axis)[islicer]
new_obj.set_axis(shifted_axis, axis=axis, inplace=True)
return new_obj.__finalize__(self)
def tshift(
self: FrameOrSeries, periods: int = 1, freq=None, axis=0
) -> FrameOrSeries:
"""
Shift the time index, using the index's frequency if available.
Parameters
----------
periods : int
Number of periods to move, can be positive or negative.
freq : DateOffset, timedelta, or str, default None
Increment to use from the tseries module
or time rule expressed as a string (e.g. 'EOM').
axis : {0 or ‘index’, 1 or ‘columns’, None}, default 0
Corresponds to the axis that contains the Index.
Returns
-------
shifted : Series/DataFrame
Notes
-----
If freq is not specified then tries to use the freq or inferred_freq
attributes of the index. If neither of those attributes exist, a
ValueError is thrown
"""
index = self._get_axis(axis)
if freq is None:
freq = getattr(index, "freq", None)
if freq is None:
freq = getattr(index, "inferred_freq", None)
if freq is None:
msg = "Freq was not given and was not set in the index"
raise ValueError(msg)
if periods == 0:
return self
if isinstance(freq, str):
freq = to_offset(freq)
block_axis = self._get_block_manager_axis(axis)
if isinstance(index, PeriodIndex):
orig_freq = to_offset(index.freq)
if freq == orig_freq:
new_data = self._data.copy()
new_data.axes[block_axis] = index.shift(periods)
elif orig_freq is not None:
raise ValueError(
f"Given freq {freq.rule_code} does not match "
f"PeriodIndex freq {orig_freq.rule_code}"
)
else:
new_data = self._data.copy()
new_data.axes[block_axis] = index.shift(periods, freq)
return self._constructor(new_data).__finalize__(self)
def truncate(
self: FrameOrSeries, before=None, after=None, axis=None, copy: bool_t = True
) -> FrameOrSeries:
"""
Truncate a Series or DataFrame before and after some index value.
This is a useful shorthand for boolean indexing based on index
values above or below certain thresholds.
Parameters
----------
before : date, str, int
Truncate all rows before this index value.
after : date, str, int
Truncate all rows after this index value.
axis : {0 or 'index', 1 or 'columns'}, optional
Axis to truncate. Truncates the index (rows) by default.
copy : bool, default is True,
Return a copy of the truncated section.
Returns
-------
type of caller
The truncated Series or DataFrame.
See Also
--------
DataFrame.loc : Select a subset of a DataFrame by label.
DataFrame.iloc : Select a subset of a DataFrame by position.
Notes
-----
If the index being truncated contains only datetime values,
`before` and `after` may be specified as strings instead of
Timestamps.
Examples
--------
>>> df = pd.DataFrame({'A': ['a', 'b', 'c', 'd', 'e'],
... 'B': ['f', 'g', 'h', 'i', 'j'],
... 'C': ['k', 'l', 'm', 'n', 'o']},
... index=[1, 2, 3, 4, 5])
>>> df
A B C
1 a f k
2 b g l
3 c h m
4 d i n
5 e j o
>>> df.truncate(before=2, after=4)
A B C
2 b g l
3 c h m
4 d i n
The columns of a DataFrame can be truncated.
>>> df.truncate(before="A", after="B", axis="columns")
A B
1 a f
2 b g
3 c h
4 d i
5 e j
For Series, only rows can be truncated.
>>> df['A'].truncate(before=2, after=4)
2 b
3 c
4 d
Name: A, dtype: object
The index values in ``truncate`` can be datetimes or string
dates.
>>> dates = pd.date_range('2016-01-01', '2016-02-01', freq='s')
>>> df = pd.DataFrame(index=dates, data={'A': 1})
>>> df.tail()
A
2016-01-31 23:59:56 1
2016-01-31 23:59:57 1
2016-01-31 23:59:58 1
2016-01-31 23:59:59 1
2016-02-01 00:00:00 1
>>> df.truncate(before=pd.Timestamp('2016-01-05'),
... after=pd.Timestamp('2016-01-10')).tail()
A
2016-01-09 23:59:56 1
2016-01-09 23:59:57 1
2016-01-09 23:59:58 1
2016-01-09 23:59:59 1
2016-01-10 00:00:00 1
Because the index is a DatetimeIndex containing only dates, we can
specify `before` and `after` as strings. They will be coerced to
Timestamps before truncation.
>>> df.truncate('2016-01-05', '2016-01-10').tail()
A
2016-01-09 23:59:56 1
2016-01-09 23:59:57 1
2016-01-09 23:59:58 1
2016-01-09 23:59:59 1
2016-01-10 00:00:00 1
Note that ``truncate`` assumes a 0 value for any unspecified time
component (midnight). This differs from partial string slicing, which
returns any partially matching dates.
>>> df.loc['2016-01-05':'2016-01-10', :].tail()
A
2016-01-10 23:59:55 1
2016-01-10 23:59:56 1
2016-01-10 23:59:57 1
2016-01-10 23:59:58 1
2016-01-10 23:59:59 1
"""
if axis is None:
axis = self._stat_axis_number
axis = self._get_axis_number(axis)
ax = self._get_axis(axis)
# GH 17935
# Check that index is sorted
if not ax.is_monotonic_increasing and not ax.is_monotonic_decreasing:
raise ValueError("truncate requires a sorted index")
# if we have a date index, convert to dates, otherwise
# treat like a slice
if ax.is_all_dates:
from pandas.core.tools.datetimes import to_datetime
before = to_datetime(before)
after = to_datetime(after)
if before is not None and after is not None:
if before > after:
raise ValueError(f"Truncate: {after} must be after {before}")
slicer = [slice(None, None)] * self._AXIS_LEN
slicer[axis] = slice(before, after)
result = self.loc[tuple(slicer)]
if isinstance(ax, MultiIndex):
setattr(result, self._get_axis_name(axis), ax.truncate(before, after))
if copy:
result = result.copy()
return result
def tz_convert(
self: FrameOrSeries, tz, axis=0, level=None, copy: bool_t = True
) -> FrameOrSeries:
"""
Convert tz-aware axis to target time zone.
Parameters
----------
tz : str or tzinfo object
axis : the axis to convert
level : int, str, default None
If axis is a MultiIndex, convert a specific level. Otherwise
must be None.
copy : bool, default True
Also make a copy of the underlying data.
Returns
-------
%(klass)s
Object with time zone converted axis.
Raises
------
TypeError
If the axis is tz-naive.
"""
axis = self._get_axis_number(axis)
ax = self._get_axis(axis)
def _tz_convert(ax, tz):
if not hasattr(ax, "tz_convert"):
if len(ax) > 0:
ax_name = self._get_axis_name(axis)
raise TypeError(
f"{ax_name} is not a valid DatetimeIndex or PeriodIndex"
)
else:
ax = DatetimeIndex([], tz=tz)
else:
ax = ax.tz_convert(tz)
return ax
# if a level is given it must be a MultiIndex level or
# equivalent to the axis name
if isinstance(ax, MultiIndex):
level = ax._get_level_number(level)
new_level = _tz_convert(ax.levels[level], tz)
ax = ax.set_levels(new_level, level=level)
else:
if level not in (None, 0, ax.name):
raise ValueError(f"The level {level} is not valid")
ax = _tz_convert(ax, tz)
result = self._constructor(self._data, copy=copy)
result = result.set_axis(ax, axis=axis, inplace=False)
return result.__finalize__(self)
def tz_localize(
self: FrameOrSeries,
tz,
axis=0,
level=None,
copy: bool_t = True,
ambiguous="raise",
nonexistent: str = "raise",
) -> FrameOrSeries:
"""
Localize tz-naive index of a Series or DataFrame to target time zone.
This operation localizes the Index. To localize the values in a
timezone-naive Series, use :meth:`Series.dt.tz_localize`.
Parameters
----------
tz : str or tzinfo
axis : the axis to localize
level : int, str, default None
If axis ia a MultiIndex, localize a specific level. Otherwise
must be None.
copy : bool, default True
Also make a copy of the underlying data.
ambiguous : 'infer', bool-ndarray, 'NaT', default 'raise'
When clocks moved backward due to DST, ambiguous times may arise.
For example in Central European Time (UTC+01), when going from
03:00 DST to 02:00 non-DST, 02:30:00 local time occurs both at
00:30:00 UTC and at 01:30:00 UTC. In such a situation, the
`ambiguous` parameter dictates how ambiguous times should be
handled.
- 'infer' will attempt to infer fall dst-transition hours based on
order
- bool-ndarray where True signifies a DST time, False designates
a non-DST time (note that this flag is only applicable for
ambiguous times)
- 'NaT' will return NaT where there are ambiguous times
- 'raise' will raise an AmbiguousTimeError if there are ambiguous
times.
nonexistent : str, default 'raise'
A nonexistent time does not exist in a particular timezone
where clocks moved forward due to DST. Valid values are:
- 'shift_forward' will shift the nonexistent time forward to the
closest existing time
- 'shift_backward' will shift the nonexistent time backward to the
closest existing time
- 'NaT' will return NaT where there are nonexistent times
- timedelta objects will shift nonexistent times by the timedelta
- 'raise' will raise an NonExistentTimeError if there are
nonexistent times.
.. versionadded:: 0.24.0
Returns
-------
Series or DataFrame
Same type as the input.
Raises
------
TypeError
If the TimeSeries is tz-aware and tz is not None.
Examples
--------
Localize local times:
>>> s = pd.Series([1],
... index=pd.DatetimeIndex(['2018-09-15 01:30:00']))
>>> s.tz_localize('CET')
2018-09-15 01:30:00+02:00 1
dtype: int64
Be careful with DST changes. When there is sequential data, pandas
can infer the DST time:
>>> s = pd.Series(range(7),
... index=pd.DatetimeIndex(['2018-10-28 01:30:00',
... '2018-10-28 02:00:00',
... '2018-10-28 02:30:00',
... '2018-10-28 02:00:00',
... '2018-10-28 02:30:00',
... '2018-10-28 03:00:00',
... '2018-10-28 03:30:00']))
>>> s.tz_localize('CET', ambiguous='infer')
2018-10-28 01:30:00+02:00 0
2018-10-28 02:00:00+02:00 1
2018-10-28 02:30:00+02:00 2
2018-10-28 02:00:00+01:00 3
2018-10-28 02:30:00+01:00 4
2018-10-28 03:00:00+01:00 5
2018-10-28 03:30:00+01:00 6
dtype: int64
In some cases, inferring the DST is impossible. In such cases, you can
pass an ndarray to the ambiguous parameter to set the DST explicitly
>>> s = pd.Series(range(3),
... index=pd.DatetimeIndex(['2018-10-28 01:20:00',
... '2018-10-28 02:36:00',
... '2018-10-28 03:46:00']))
>>> s.tz_localize('CET', ambiguous=np.array([True, True, False]))
2018-10-28 01:20:00+02:00 0
2018-10-28 02:36:00+02:00 1
2018-10-28 03:46:00+01:00 2
dtype: int64
If the DST transition causes nonexistent times, you can shift these
dates forward or backwards with a timedelta object or `'shift_forward'`
or `'shift_backwards'`.
>>> s = pd.Series(range(2),
... index=pd.DatetimeIndex(['2015-03-29 02:30:00',
... '2015-03-29 03:30:00']))
>>> s.tz_localize('Europe/Warsaw', nonexistent='shift_forward')
2015-03-29 03:00:00+02:00 0
2015-03-29 03:30:00+02:00 1
dtype: int64
>>> s.tz_localize('Europe/Warsaw', nonexistent='shift_backward')
2015-03-29 01:59:59.999999999+01:00 0
2015-03-29 03:30:00+02:00 1
dtype: int64
>>> s.tz_localize('Europe/Warsaw', nonexistent=pd.Timedelta('1H'))
2015-03-29 03:30:00+02:00 0
2015-03-29 03:30:00+02:00 1
dtype: int64
"""
nonexistent_options = ("raise", "NaT", "shift_forward", "shift_backward")
if nonexistent not in nonexistent_options and not isinstance(
nonexistent, timedelta
):
raise ValueError(
"The nonexistent argument must be one of 'raise', "
"'NaT', 'shift_forward', 'shift_backward' or "
"a timedelta object"
)
axis = self._get_axis_number(axis)
ax = self._get_axis(axis)
def _tz_localize(ax, tz, ambiguous, nonexistent):
if not hasattr(ax, "tz_localize"):
if len(ax) > 0:
ax_name = self._get_axis_name(axis)
raise TypeError(
f"{ax_name} is not a valid DatetimeIndex or PeriodIndex"
)
else:
ax = DatetimeIndex([], tz=tz)
else:
ax = ax.tz_localize(tz, ambiguous=ambiguous, nonexistent=nonexistent)
return ax
# if a level is given it must be a MultiIndex level or
# equivalent to the axis name
if isinstance(ax, MultiIndex):
level = ax._get_level_number(level)
new_level = _tz_localize(ax.levels[level], tz, ambiguous, nonexistent)
ax = ax.set_levels(new_level, level=level)
else:
if level not in (None, 0, ax.name):
raise ValueError(f"The level {level} is not valid")
ax = _tz_localize(ax, tz, ambiguous, nonexistent)
result = self._constructor(self._data, copy=copy)
result = result.set_axis(ax, axis=axis, inplace=False)
return result.__finalize__(self)
# ----------------------------------------------------------------------
# Numeric Methods
def abs(self: FrameOrSeries) -> FrameOrSeries:
"""
Return a Series/DataFrame with absolute numeric value of each element.
This function only applies to elements that are all numeric.
Returns
-------
abs
Series/DataFrame containing the absolute value of each element.
See Also
--------
numpy.absolute : Calculate the absolute value element-wise.
Notes
-----
For ``complex`` inputs, ``1.2 + 1j``, the absolute value is
:math:`\\sqrt{ a^2 + b^2 }`.
Examples
--------
Absolute numeric values in a Series.
>>> s = pd.Series([-1.10, 2, -3.33, 4])
>>> s.abs()
0 1.10
1 2.00
2 3.33
3 4.00
dtype: float64
Absolute numeric values in a Series with complex numbers.
>>> s = pd.Series([1.2 + 1j])
>>> s.abs()
0 1.56205
dtype: float64
Absolute numeric values in a Series with a Timedelta element.
>>> s = pd.Series([pd.Timedelta('1 days')])
>>> s.abs()
0 1 days
dtype: timedelta64[ns]
Select rows with data closest to certain value using argsort (from
`StackOverflow <https://stackoverflow.com/a/17758115>`__).
>>> df = pd.DataFrame({
... 'a': [4, 5, 6, 7],
... 'b': [10, 20, 30, 40],
... 'c': [100, 50, -30, -50]
... })
>>> df
a b c
0 4 10 100
1 5 20 50
2 6 30 -30
3 7 40 -50
>>> df.loc[(df.c - 43).abs().argsort()]
a b c
1 5 20 50
0 4 10 100
2 6 30 -30
3 7 40 -50
"""
return np.abs(self)
def describe(
self: FrameOrSeries, percentiles=None, include=None, exclude=None
) -> FrameOrSeries:
"""
Generate descriptive statistics.
Descriptive statistics include those that summarize the central
tendency, dispersion and shape of a
dataset's distribution, excluding ``NaN`` values.
Analyzes both numeric and object series, as well
as ``DataFrame`` column sets of mixed data types. The output
will vary depending on what is provided. Refer to the notes
below for more detail.
Parameters
----------
percentiles : list-like of numbers, optional
The percentiles to include in the output. All should
fall between 0 and 1. The default is
``[.25, .5, .75]``, which returns the 25th, 50th, and
75th percentiles.
include : 'all', list-like of dtypes or None (default), optional
A white list of data types to include in the result. Ignored
for ``Series``. Here are the options:
- 'all' : All columns of the input will be included in the output.
- A list-like of dtypes : Limits the results to the
provided data types.
To limit the result to numeric types submit
``numpy.number``. To limit it instead to object columns submit
the ``numpy.object`` data type. Strings
can also be used in the style of
``select_dtypes`` (e.g. ``df.describe(include=['O'])``). To
select pandas categorical columns, use ``'category'``
- None (default) : The result will include all numeric columns.
exclude : list-like of dtypes or None (default), optional,
A black list of data types to omit from the result. Ignored
for ``Series``. Here are the options:
- A list-like of dtypes : Excludes the provided data types
from the result. To exclude numeric types submit
``numpy.number``. To exclude object columns submit the data
type ``numpy.object``. Strings can also be used in the style of
``select_dtypes`` (e.g. ``df.describe(include=['O'])``). To
exclude pandas categorical columns, use ``'category'``
- None (default) : The result will exclude nothing.
Returns
-------
Series or DataFrame
Summary statistics of the Series or Dataframe provided.
See Also
--------
DataFrame.count: Count number of non-NA/null observations.
DataFrame.max: Maximum of the values in the object.
DataFrame.min: Minimum of the values in the object.
DataFrame.mean: Mean of the values.
DataFrame.std: Standard deviation of the observations.
DataFrame.select_dtypes: Subset of a DataFrame including/excluding
columns based on their dtype.
Notes
-----
For numeric data, the result's index will include ``count``,
``mean``, ``std``, ``min``, ``max`` as well as lower, ``50`` and
upper percentiles. By default the lower percentile is ``25`` and the
upper percentile is ``75``. The ``50`` percentile is the
same as the median.
For object data (e.g. strings or timestamps), the result's index
will include ``count``, ``unique``, ``top``, and ``freq``. The ``top``
is the most common value. The ``freq`` is the most common value's
frequency. Timestamps also include the ``first`` and ``last`` items.
If multiple object values have the highest count, then the
``count`` and ``top`` results will be arbitrarily chosen from
among those with the highest count.
For mixed data types provided via a ``DataFrame``, the default is to
return only an analysis of numeric columns. If the dataframe consists
only of object and categorical data without any numeric columns, the
default is to return an analysis of both the object and categorical
columns. If ``include='all'`` is provided as an option, the result
will include a union of attributes of each type.
The `include` and `exclude` parameters can be used to limit
which columns in a ``DataFrame`` are analyzed for the output.
The parameters are ignored when analyzing a ``Series``.
Examples
--------
Describing a numeric ``Series``.
>>> s = pd.Series([1, 2, 3])
>>> s.describe()
count 3.0
mean 2.0
std 1.0
min 1.0
25% 1.5
50% 2.0
75% 2.5
max 3.0
dtype: float64
Describing a categorical ``Series``.
>>> s = pd.Series(['a', 'a', 'b', 'c'])
>>> s.describe()
count 4
unique 3
top a
freq 2
dtype: object
Describing a timestamp ``Series``.
>>> s = pd.Series([
... np.datetime64("2000-01-01"),
... np.datetime64("2010-01-01"),
... np.datetime64("2010-01-01")
... ])
>>> s.describe()
count 3
unique 2
top 2010-01-01 00:00:00
freq 2
first 2000-01-01 00:00:00
last 2010-01-01 00:00:00
dtype: object
Describing a ``DataFrame``. By default only numeric fields
are returned.
>>> df = pd.DataFrame({'categorical': pd.Categorical(['d','e','f']),
... 'numeric': [1, 2, 3],
... 'object': ['a', 'b', 'c']
... })
>>> df.describe()
numeric
count 3.0
mean 2.0
std 1.0
min 1.0
25% 1.5
50% 2.0
75% 2.5
max 3.0
Describing all columns of a ``DataFrame`` regardless of data type.
>>> df.describe(include='all')
categorical numeric object
count 3 3.0 3
unique 3 NaN 3
top f NaN c
freq 1 NaN 1
mean NaN 2.0 NaN
std NaN 1.0 NaN
min NaN 1.0 NaN
25% NaN 1.5 NaN
50% NaN 2.0 NaN
75% NaN 2.5 NaN
max NaN 3.0 NaN
Describing a column from a ``DataFrame`` by accessing it as
an attribute.
>>> df.numeric.describe()
count 3.0
mean 2.0
std 1.0
min 1.0
25% 1.5
50% 2.0
75% 2.5
max 3.0
Name: numeric, dtype: float64
Including only numeric columns in a ``DataFrame`` description.
>>> df.describe(include=[np.number])
numeric
count 3.0
mean 2.0
std 1.0
min 1.0
25% 1.5
50% 2.0
75% 2.5
max 3.0
Including only string columns in a ``DataFrame`` description.
>>> df.describe(include=[np.object])
object
count 3
unique 3
top c
freq 1
Including only categorical columns from a ``DataFrame`` description.
>>> df.describe(include=['category'])
categorical
count 3
unique 3
top f
freq 1
Excluding numeric columns from a ``DataFrame`` description.
>>> df.describe(exclude=[np.number])
categorical object
count 3 3
unique 3 3
top f c
freq 1 1
Excluding object columns from a ``DataFrame`` description.
>>> df.describe(exclude=[np.object])
categorical numeric
count 3 3.0
unique 3 NaN
top f NaN
freq 1 NaN
mean NaN 2.0
std NaN 1.0
min NaN 1.0
25% NaN 1.5
50% NaN 2.0
75% NaN 2.5
max NaN 3.0
"""
if self.ndim == 2 and self.columns.size == 0:
raise ValueError("Cannot describe a DataFrame without columns")
if percentiles is not None:
# explicit conversion of `percentiles` to list
percentiles = list(percentiles)
# get them all to be in [0, 1]
validate_percentile(percentiles)
# median should always be included
if 0.5 not in percentiles:
percentiles.append(0.5)
percentiles = np.asarray(percentiles)
else:
percentiles = np.array([0.25, 0.5, 0.75])
# sort and check for duplicates
unique_pcts = np.unique(percentiles)
if len(unique_pcts) < len(percentiles):
raise ValueError("percentiles cannot contain duplicates")
percentiles = unique_pcts
formatted_percentiles = format_percentiles(percentiles)
def describe_numeric_1d(series):
stat_index = (
["count", "mean", "std", "min"] + formatted_percentiles + ["max"]
)
d = (
[series.count(), series.mean(), series.std(), series.min()]
+ series.quantile(percentiles).tolist()
+ [series.max()]
)
return pd.Series(d, index=stat_index, name=series.name)
def describe_categorical_1d(data):
names = ["count", "unique"]
objcounts = data.value_counts()
count_unique = len(objcounts[objcounts != 0])
result = [data.count(), count_unique]
dtype = None
if result[1] > 0:
top, freq = objcounts.index[0], objcounts.iloc[0]
names += ["top", "freq"]
result += [top, freq]
# If the DataFrame is empty, set 'top' and 'freq' to None
# to maintain output shape consistency
else:
names += ["top", "freq"]
result += [np.nan, np.nan]
dtype = "object"
return pd.Series(result, index=names, name=data.name, dtype=dtype)
def describe_timestamp_1d(data):
# GH-30164
stat_index = ["count", "mean", "min"] + formatted_percentiles + ["max"]
d = (
[data.count(), data.mean(), data.min()]
+ data.quantile(percentiles).tolist()
+ [data.max()]
)
return pd.Series(d, index=stat_index, name=data.name)
def describe_1d(data):
if is_bool_dtype(data):
return describe_categorical_1d(data)
elif is_numeric_dtype(data):
return describe_numeric_1d(data)
elif is_datetime64_any_dtype(data):
return describe_timestamp_1d(data)
elif is_timedelta64_dtype(data):
return describe_numeric_1d(data)
else:
return describe_categorical_1d(data)
if self.ndim == 1:
return describe_1d(self)
elif (include is None) and (exclude is None):
# when some numerics are found, keep only numerics
data = self.select_dtypes(include=[np.number])
if len(data.columns) == 0:
data = self
elif include == "all":
if exclude is not None:
msg = "exclude must be None when include is 'all'"
raise ValueError(msg)
data = self
else:
data = self.select_dtypes(include=include, exclude=exclude)
ldesc = [describe_1d(s) for _, s in data.items()]
# set a convenient order for rows
names: List[Optional[Hashable]] = []
ldesc_indexes = sorted((x.index for x in ldesc), key=len)
for idxnames in ldesc_indexes:
for name in idxnames:
if name not in names:
names.append(name)
d = pd.concat([x.reindex(names, copy=False) for x in ldesc], axis=1, sort=False)
d.columns = data.columns.copy()
return d
_shared_docs[
"pct_change"
] = """
Percentage change between the current and a prior element.
Computes the percentage change from the immediately previous row by
default. This is useful in comparing the percentage of change in a time
series of elements.
Parameters
----------
periods : int, default 1
Periods to shift for forming percent change.
fill_method : str, default 'pad'
How to handle NAs before computing percent changes.
limit : int, default None
The number of consecutive NAs to fill before stopping.
freq : DateOffset, timedelta, or str, optional
Increment to use from time series API (e.g. 'M' or BDay()).
**kwargs
Additional keyword arguments are passed into
`DataFrame.shift` or `Series.shift`.
Returns
-------
chg : Series or DataFrame
The same type as the calling object.
See Also
--------
Series.diff : Compute the difference of two elements in a Series.
DataFrame.diff : Compute the difference of two elements in a DataFrame.
Series.shift : Shift the index by some number of periods.
DataFrame.shift : Shift the index by some number of periods.
Examples
--------
**Series**
>>> s = pd.Series([90, 91, 85])
>>> s
0 90
1 91
2 85
dtype: int64
>>> s.pct_change()
0 NaN
1 0.011111
2 -0.065934
dtype: float64
>>> s.pct_change(periods=2)
0 NaN
1 NaN
2 -0.055556
dtype: float64
See the percentage change in a Series where filling NAs with last
valid observation forward to next valid.
>>> s = pd.Series([90, 91, None, 85])
>>> s
0 90.0
1 91.0
2 NaN
3 85.0
dtype: float64
>>> s.pct_change(fill_method='ffill')
0 NaN
1 0.011111
2 0.000000
3 -0.065934
dtype: float64
**DataFrame**
Percentage change in French franc, Deutsche Mark, and Italian lira from
1980-01-01 to 1980-03-01.
>>> df = pd.DataFrame({
... 'FR': [4.0405, 4.0963, 4.3149],
... 'GR': [1.7246, 1.7482, 1.8519],
... 'IT': [804.74, 810.01, 860.13]},
... index=['1980-01-01', '1980-02-01', '1980-03-01'])
>>> df
FR GR IT
1980-01-01 4.0405 1.7246 804.74
1980-02-01 4.0963 1.7482 810.01
1980-03-01 4.3149 1.8519 860.13
>>> df.pct_change()
FR GR IT
1980-01-01 NaN NaN NaN
1980-02-01 0.013810 0.013684 0.006549
1980-03-01 0.053365 0.059318 0.061876
Percentage of change in GOOG and APPL stock volume. Shows computing
the percentage change between columns.
>>> df = pd.DataFrame({
... '2016': [1769950, 30586265],
... '2015': [1500923, 40912316],
... '2014': [1371819, 41403351]},
... index=['GOOG', 'APPL'])
>>> df
2016 2015 2014
GOOG 1769950 1500923 1371819
APPL 30586265 40912316 41403351
>>> df.pct_change(axis='columns')
2016 2015 2014
GOOG NaN -0.151997 -0.086016
APPL NaN 0.337604 0.012002
"""
@Appender(_shared_docs["pct_change"] % _shared_doc_kwargs)
def pct_change(
self: FrameOrSeries,
periods=1,
fill_method="pad",
limit=None,
freq=None,
**kwargs,
) -> FrameOrSeries:
# TODO: Not sure if above is correct - need someone to confirm.
axis = self._get_axis_number(kwargs.pop("axis", self._stat_axis_name))
if fill_method is None:
data = self
else:
data = self._ensure_type(
self.fillna(method=fill_method, axis=axis, limit=limit)
)
rs = data.div(data.shift(periods=periods, freq=freq, axis=axis, **kwargs)) - 1
if freq is not None:
# Shift method is implemented differently when freq is not None
# We want to restore the original index
rs = rs.loc[~rs.index.duplicated()]
rs = rs.reindex_like(data)
return rs
def _agg_by_level(self, name, axis=0, level=0, skipna=True, **kwargs):
if axis is None:
raise ValueError("Must specify 'axis' when aggregating by level.")
grouped = self.groupby(level=level, axis=axis, sort=False)
if hasattr(grouped, name) and skipna:
return getattr(grouped, name)(**kwargs)
axis = self._get_axis_number(axis)
method = getattr(type(self), name)
applyf = lambda x: method(x, axis=axis, skipna=skipna, **kwargs)
return grouped.aggregate(applyf)
@classmethod
def _add_numeric_operations(cls):
"""
Add the operations to the cls; evaluate the doc strings again
"""
axis_descr, name, name2 = _doc_parms(cls)
cls.any = _make_logical_function(
cls,
"any",
name,
name2,
axis_descr,
_any_desc,
nanops.nanany,
_any_see_also,
_any_examples,
empty_value=False,
)
cls.all = _make_logical_function(
cls,
"all",
name,
name2,
axis_descr,
_all_desc,
nanops.nanall,
_all_see_also,
_all_examples,
empty_value=True,
)
@Substitution(
desc="Return the mean absolute deviation of the values "
"for the requested axis.",
name1=name,
name2=name2,
axis_descr=axis_descr,
min_count="",
see_also="",
examples="",
)
@Appender(_num_doc_mad)
def mad(self, axis=None, skipna=None, level=None):
if skipna is None:
skipna = True
if axis is None:
axis = self._stat_axis_number
if level is not None:
return self._agg_by_level("mad", axis=axis, level=level, skipna=skipna)
data = self._get_numeric_data()
if axis == 0:
demeaned = data - data.mean(axis=0)
else:
demeaned = data.sub(data.mean(axis=1), axis=0)
return np.abs(demeaned).mean(axis=axis, skipna=skipna)
cls.mad = mad
cls.sem = _make_stat_function_ddof(
cls,
"sem",
name,
name2,
axis_descr,
"Return unbiased standard error of the mean over requested "
"axis.\n\nNormalized by N-1 by default. This can be changed "
"using the ddof argument",
nanops.nansem,
)
cls.var = _make_stat_function_ddof(
cls,
"var",
name,
name2,
axis_descr,
"Return unbiased variance over requested axis.\n\nNormalized by "
"N-1 by default. This can be changed using the ddof argument",
nanops.nanvar,
)
cls.std = _make_stat_function_ddof(
cls,
"std",
name,
name2,
axis_descr,
"Return sample standard deviation over requested axis."
"\n\nNormalized by N-1 by default. This can be changed using the "
"ddof argument",
nanops.nanstd,
)
cls.cummin = _make_cum_function(
cls,
"cummin",
name,
name2,
axis_descr,
"minimum",
np.minimum.accumulate,
"min",
np.inf,
np.nan,
_cummin_examples,
)
cls.cumsum = _make_cum_function(
cls,
"cumsum",
name,
name2,
axis_descr,
"sum",
np.cumsum,
"sum",
0.0,
np.nan,
_cumsum_examples,
)
cls.cumprod = _make_cum_function(
cls,
"cumprod",
name,
name2,
axis_descr,
"product",
np.cumprod,
"prod",
1.0,
np.nan,
_cumprod_examples,
)
cls.cummax = _make_cum_function(
cls,
"cummax",
name,
name2,
axis_descr,
"maximum",
np.maximum.accumulate,
"max",
-np.inf,
np.nan,
_cummax_examples,
)
cls.sum = _make_min_count_stat_function(
cls,
"sum",
name,
name2,
axis_descr,
"""Return the sum of the values for the requested axis.\n
This is equivalent to the method ``numpy.sum``.""",
nanops.nansum,
_stat_func_see_also,
_sum_examples,
)
cls.mean = _make_stat_function(
cls,
"mean",
name,
name2,
axis_descr,
"Return the mean of the values for the requested axis.",
nanops.nanmean,
)
cls.skew = _make_stat_function(
cls,
"skew",
name,
name2,
axis_descr,
"Return unbiased skew over requested axis.\n\nNormalized by N-1.",
nanops.nanskew,
)
cls.kurt = _make_stat_function(
cls,
"kurt",
name,
name2,
axis_descr,
"Return unbiased kurtosis over requested axis.\n\n"
"Kurtosis obtained using Fisher's definition of\n"
"kurtosis (kurtosis of normal == 0.0). Normalized "
"by N-1.",
nanops.nankurt,
)
cls.kurtosis = cls.kurt
cls.prod = _make_min_count_stat_function(
cls,
"prod",
name,
name2,
axis_descr,
"Return the product of the values for the requested axis.",
nanops.nanprod,
examples=_prod_examples,
)
cls.product = cls.prod
cls.median = _make_stat_function(
cls,
"median",
name,
name2,
axis_descr,
"Return the median of the values for the requested axis.",
nanops.nanmedian,
)
cls.max = _make_stat_function(
cls,
"max",
name,
name2,
axis_descr,
"""Return the maximum of the values for the requested axis.\n
If you want the *index* of the maximum, use ``idxmax``. This is
the equivalent of the ``numpy.ndarray`` method ``argmax``.""",
nanops.nanmax,
_stat_func_see_also,
_max_examples,
)
cls.min = _make_stat_function(
cls,
"min",
name,
name2,
axis_descr,
"""Return the minimum of the values for the requested axis.\n
If you want the *index* of the minimum, use ``idxmin``. This is
the equivalent of the ``numpy.ndarray`` method ``argmin``.""",
nanops.nanmin,
_stat_func_see_also,
_min_examples,
)
@classmethod
def _add_series_or_dataframe_operations(cls):
"""
Add the series or dataframe only operations to the cls; evaluate
the doc strings again.
"""
from pandas.core.window import EWM, Expanding, Rolling, Window
@Appender(Rolling.__doc__)
def rolling(
self,
window,
min_periods=None,
center=False,
win_type=None,
on=None,
axis=0,
closed=None,
):
axis = self._get_axis_number(axis)
if win_type is not None:
return Window(
self,
window=window,
min_periods=min_periods,
center=center,
win_type=win_type,
on=on,
axis=axis,
closed=closed,
)
return Rolling(
self,
window=window,
min_periods=min_periods,
center=center,
win_type=win_type,
on=on,
axis=axis,
closed=closed,
)
cls.rolling = rolling
@Appender(Expanding.__doc__)
def expanding(self, min_periods=1, center=False, axis=0):
axis = self._get_axis_number(axis)
return Expanding(self, min_periods=min_periods, center=center, axis=axis)
cls.expanding = expanding
@Appender(EWM.__doc__)
def ewm(
self,
com=None,
span=None,
halflife=None,
alpha=None,
min_periods=0,
adjust=True,
ignore_na=False,
axis=0,
):
axis = self._get_axis_number(axis)
return EWM(
self,
com=com,
span=span,
halflife=halflife,
alpha=alpha,
min_periods=min_periods,
adjust=adjust,
ignore_na=ignore_na,
axis=axis,
)
cls.ewm = ewm
@Appender(_shared_docs["transform"] % dict(axis="", **_shared_doc_kwargs))
def transform(self, func, *args, **kwargs):
result = self.agg(func, *args, **kwargs)
if is_scalar(result) or len(result) != len(self):
raise ValueError("transforms cannot produce aggregated results")
return result
# ----------------------------------------------------------------------
# Misc methods
_shared_docs[
"valid_index"
] = """
Return index for %(position)s non-NA/null value.
Returns
-------
scalar : type of index
Notes
-----
If all elements are non-NA/null, returns None.
Also returns None for empty %(klass)s.
"""
def _find_valid_index(self, how: str):
"""
Retrieves the index of the first valid value.
Parameters
----------
how : {'first', 'last'}
Use this parameter to change between the first or last valid index.
Returns
-------
idx_first_valid : type of index
"""
idxpos = find_valid_index(self._values, how)
if idxpos is None:
return None
return self.index[idxpos]
@Appender(
_shared_docs["valid_index"] % {"position": "first", "klass": "Series/DataFrame"}
)
def first_valid_index(self):
return self._find_valid_index("first")
@Appender(
_shared_docs["valid_index"] % {"position": "last", "klass": "Series/DataFrame"}
)
def last_valid_index(self):
return self._find_valid_index("last")
def _doc_parms(cls):
"""Return a tuple of the doc parms."""
axis_descr = (
f"{{{', '.join(f'{a} ({i})' for i, a in enumerate(cls._AXIS_ORDERS))}}}"
)
name = cls._constructor_sliced.__name__ if cls._AXIS_LEN > 1 else "scalar"
name2 = cls.__name__
return axis_descr, name, name2
_num_doc = """
%(desc)s
Parameters
----------
axis : %(axis_descr)s
Axis for the function to be applied on.
skipna : bool, default True
Exclude NA/null values when computing the result.
level : int or level name, default None
If the axis is a MultiIndex (hierarchical), count along a
particular level, collapsing into a %(name1)s.
numeric_only : bool, default None
Include only float, int, boolean columns. If None, will attempt to use
everything, then use only numeric data. Not implemented for Series.
%(min_count)s\
**kwargs
Additional keyword arguments to be passed to the function.
Returns
-------
%(name1)s or %(name2)s (if level specified)\
%(see_also)s\
%(examples)s
"""
_num_doc_mad = """
%(desc)s
Parameters
----------
axis : %(axis_descr)s
Axis for the function to be applied on.
skipna : bool, default None
Exclude NA/null values when computing the result.
level : int or level name, default None
If the axis is a MultiIndex (hierarchical), count along a
particular level, collapsing into a %(name1)s.
Returns
-------
%(name1)s or %(name2)s (if level specified)\
%(see_also)s\
%(examples)s
"""
_num_ddof_doc = """
%(desc)s
Parameters
----------
axis : %(axis_descr)s
skipna : bool, default True
Exclude NA/null values. If an entire row/column is NA, the result
will be NA.
level : int or level name, default None
If the axis is a MultiIndex (hierarchical), count along a
particular level, collapsing into a %(name1)s.
ddof : int, default 1
Delta Degrees of Freedom. The divisor used in calculations is N - ddof,
where N represents the number of elements.
numeric_only : bool, default None
Include only float, int, boolean columns. If None, will attempt to use
everything, then use only numeric data. Not implemented for Series.
Returns
-------
%(name1)s or %(name2)s (if level specified)\n"""
_bool_doc = """
%(desc)s
Parameters
----------
axis : {0 or 'index', 1 or 'columns', None}, default 0
Indicate which axis or axes should be reduced.
* 0 / 'index' : reduce the index, return a Series whose index is the
original column labels.
* 1 / 'columns' : reduce the columns, return a Series whose index is the
original index.
* None : reduce all axes, return a scalar.
bool_only : bool, default None
Include only boolean columns. If None, will attempt to use everything,
then use only boolean data. Not implemented for Series.
skipna : bool, default True
Exclude NA/null values. If the entire row/column is NA and skipna is
True, then the result will be %(empty_value)s, as for an empty row/column.
If skipna is False, then NA are treated as True, because these are not
equal to zero.
level : int or level name, default None
If the axis is a MultiIndex (hierarchical), count along a
particular level, collapsing into a %(name1)s.
**kwargs : any, default None
Additional keywords have no effect but might be accepted for
compatibility with NumPy.
Returns
-------
%(name1)s or %(name2)s
If level is specified, then, %(name2)s is returned; otherwise, %(name1)s
is returned.
%(see_also)s
%(examples)s"""
_all_desc = """\
Return whether all elements are True, potentially over an axis.
Returns True unless there at least one element within a series or
along a Dataframe axis that is False or equivalent (e.g. zero or
empty)."""
_all_examples = """\
Examples
--------
**Series**
>>> pd.Series([True, True]).all()
True
>>> pd.Series([True, False]).all()
False
>>> pd.Series([]).all()
True
>>> pd.Series([np.nan]).all()
True
>>> pd.Series([np.nan]).all(skipna=False)
True
**DataFrames**
Create a dataframe from a dictionary.
>>> df = pd.DataFrame({'col1': [True, True], 'col2': [True, False]})
>>> df
col1 col2
0 True True
1 True False
Default behaviour checks if column-wise values all return True.
>>> df.all()
col1 True
col2 False
dtype: bool
Specify ``axis='columns'`` to check if row-wise values all return True.
>>> df.all(axis='columns')
0 True
1 False
dtype: bool
Or ``axis=None`` for whether every value is True.
>>> df.all(axis=None)
False
"""
_all_see_also = """\
See Also
--------
Series.all : Return True if all elements are True.
DataFrame.any : Return True if one (or more) elements are True.
"""
_cnum_doc = """
Return cumulative %(desc)s over a DataFrame or Series axis.
Returns a DataFrame or Series of the same size containing the cumulative
%(desc)s.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
The index or the name of the axis. 0 is equivalent to None or 'index'.
skipna : bool, default True
Exclude NA/null values. If an entire row/column is NA, the result
will be NA.
*args, **kwargs :
Additional keywords have no effect but might be accepted for
compatibility with NumPy.
Returns
-------
%(name1)s or %(name2)s
See Also
--------
core.window.Expanding.%(accum_func_name)s : Similar functionality
but ignores ``NaN`` values.
%(name2)s.%(accum_func_name)s : Return the %(desc)s over
%(name2)s axis.
%(name2)s.cummax : Return cumulative maximum over %(name2)s axis.
%(name2)s.cummin : Return cumulative minimum over %(name2)s axis.
%(name2)s.cumsum : Return cumulative sum over %(name2)s axis.
%(name2)s.cumprod : Return cumulative product over %(name2)s axis.
%(examples)s"""
_cummin_examples = """\
Examples
--------
**Series**
>>> s = pd.Series([2, np.nan, 5, -1, 0])
>>> s
0 2.0
1 NaN
2 5.0
3 -1.0
4 0.0
dtype: float64
By default, NA values are ignored.
>>> s.cummin()
0 2.0
1 NaN
2 2.0
3 -1.0
4 -1.0
dtype: float64
To include NA values in the operation, use ``skipna=False``
>>> s.cummin(skipna=False)
0 2.0
1 NaN
2 NaN
3 NaN
4 NaN
dtype: float64
**DataFrame**
>>> df = pd.DataFrame([[2.0, 1.0],
... [3.0, np.nan],
... [1.0, 0.0]],
... columns=list('AB'))
>>> df
A B
0 2.0 1.0
1 3.0 NaN
2 1.0 0.0
By default, iterates over rows and finds the minimum
in each column. This is equivalent to ``axis=None`` or ``axis='index'``.
>>> df.cummin()
A B
0 2.0 1.0
1 2.0 NaN
2 1.0 0.0
To iterate over columns and find the minimum in each row,
use ``axis=1``
>>> df.cummin(axis=1)
A B
0 2.0 1.0
1 3.0 NaN
2 1.0 0.0
"""
_cumsum_examples = """\
Examples
--------
**Series**
>>> s = pd.Series([2, np.nan, 5, -1, 0])
>>> s
0 2.0
1 NaN
2 5.0
3 -1.0
4 0.0
dtype: float64
By default, NA values are ignored.
>>> s.cumsum()
0 2.0
1 NaN
2 7.0
3 6.0
4 6.0
dtype: float64
To include NA values in the operation, use ``skipna=False``
>>> s.cumsum(skipna=False)
0 2.0
1 NaN
2 NaN
3 NaN
4 NaN
dtype: float64
**DataFrame**
>>> df = pd.DataFrame([[2.0, 1.0],
... [3.0, np.nan],
... [1.0, 0.0]],
... columns=list('AB'))
>>> df
A B
0 2.0 1.0
1 3.0 NaN
2 1.0 0.0
By default, iterates over rows and finds the sum
in each column. This is equivalent to ``axis=None`` or ``axis='index'``.
>>> df.cumsum()
A B
0 2.0 1.0
1 5.0 NaN
2 6.0 1.0
To iterate over columns and find the sum in each row,
use ``axis=1``
>>> df.cumsum(axis=1)
A B
0 2.0 3.0
1 3.0 NaN
2 1.0 1.0
"""
_cumprod_examples = """\
Examples
--------
**Series**
>>> s = pd.Series([2, np.nan, 5, -1, 0])
>>> s
0 2.0
1 NaN
2 5.0
3 -1.0
4 0.0
dtype: float64
By default, NA values are ignored.
>>> s.cumprod()
0 2.0
1 NaN
2 10.0
3 -10.0
4 -0.0
dtype: float64
To include NA values in the operation, use ``skipna=False``
>>> s.cumprod(skipna=False)
0 2.0
1 NaN
2 NaN
3 NaN
4 NaN
dtype: float64
**DataFrame**
>>> df = pd.DataFrame([[2.0, 1.0],
... [3.0, np.nan],
... [1.0, 0.0]],
... columns=list('AB'))
>>> df
A B
0 2.0 1.0
1 3.0 NaN
2 1.0 0.0
By default, iterates over rows and finds the product
in each column. This is equivalent to ``axis=None`` or ``axis='index'``.
>>> df.cumprod()
A B
0 2.0 1.0
1 6.0 NaN
2 6.0 0.0
To iterate over columns and find the product in each row,
use ``axis=1``
>>> df.cumprod(axis=1)
A B
0 2.0 2.0
1 3.0 NaN
2 1.0 0.0
"""
_cummax_examples = """\
Examples
--------
**Series**
>>> s = pd.Series([2, np.nan, 5, -1, 0])
>>> s
0 2.0
1 NaN
2 5.0
3 -1.0
4 0.0
dtype: float64
By default, NA values are ignored.
>>> s.cummax()
0 2.0
1 NaN
2 5.0
3 5.0
4 5.0
dtype: float64
To include NA values in the operation, use ``skipna=False``
>>> s.cummax(skipna=False)
0 2.0
1 NaN
2 NaN
3 NaN
4 NaN
dtype: float64
**DataFrame**
>>> df = pd.DataFrame([[2.0, 1.0],
... [3.0, np.nan],
... [1.0, 0.0]],
... columns=list('AB'))
>>> df
A B
0 2.0 1.0
1 3.0 NaN
2 1.0 0.0
By default, iterates over rows and finds the maximum
in each column. This is equivalent to ``axis=None`` or ``axis='index'``.
>>> df.cummax()
A B
0 2.0 1.0
1 3.0 NaN
2 3.0 1.0
To iterate over columns and find the maximum in each row,
use ``axis=1``
>>> df.cummax(axis=1)
A B
0 2.0 2.0
1 3.0 NaN
2 1.0 1.0
"""
_any_see_also = """\
See Also
--------
numpy.any : Numpy version of this method.
Series.any : Return whether any element is True.
Series.all : Return whether all elements are True.
DataFrame.any : Return whether any element is True over requested axis.
DataFrame.all : Return whether all elements are True over requested axis.
"""
_any_desc = """\
Return whether any element is True, potentially over an axis.
Returns False unless there at least one element within a series or
along a Dataframe axis that is True or equivalent (e.g. non-zero or
non-empty)."""
_any_examples = """\
Examples
--------
**Series**
For Series input, the output is a scalar indicating whether any element
is True.
>>> pd.Series([False, False]).any()
False
>>> pd.Series([True, False]).any()
True
>>> pd.Series([]).any()
False
>>> pd.Series([np.nan]).any()
False
>>> pd.Series([np.nan]).any(skipna=False)
True
**DataFrame**
Whether each column contains at least one True element (the default).
>>> df = pd.DataFrame({"A": [1, 2], "B": [0, 2], "C": [0, 0]})
>>> df
A B C
0 1 0 0
1 2 2 0
>>> df.any()
A True
B True
C False
dtype: bool
Aggregating over the columns.
>>> df = pd.DataFrame({"A": [True, False], "B": [1, 2]})
>>> df
A B
0 True 1
1 False 2
>>> df.any(axis='columns')
0 True
1 True
dtype: bool
>>> df = pd.DataFrame({"A": [True, False], "B": [1, 0]})
>>> df
A B
0 True 1
1 False 0
>>> df.any(axis='columns')
0 True
1 False
dtype: bool
Aggregating over the entire DataFrame with ``axis=None``.
>>> df.any(axis=None)
True
`any` for an empty DataFrame is an empty Series.
>>> pd.DataFrame([]).any()
Series([], dtype: bool)
"""
_shared_docs[
"stat_func_example"
] = """
Examples
--------
>>> idx = pd.MultiIndex.from_arrays([
... ['warm', 'warm', 'cold', 'cold'],
... ['dog', 'falcon', 'fish', 'spider']],
... names=['blooded', 'animal'])
>>> s = pd.Series([4, 2, 0, 8], name='legs', index=idx)
>>> s
blooded animal
warm dog 4
falcon 2
cold fish 0
spider 8
Name: legs, dtype: int64
>>> s.{stat_func}()
{default_output}
{verb} using level names, as well as indices.
>>> s.{stat_func}(level='blooded')
blooded
warm {level_output_0}
cold {level_output_1}
Name: legs, dtype: int64
>>> s.{stat_func}(level=0)
blooded
warm {level_output_0}
cold {level_output_1}
Name: legs, dtype: int64"""
_sum_examples = _shared_docs["stat_func_example"].format(
stat_func="sum", verb="Sum", default_output=14, level_output_0=6, level_output_1=8
)
_sum_examples += """
By default, the sum of an empty or all-NA Series is ``0``.
>>> pd.Series([]).sum() # min_count=0 is the default
0.0
This can be controlled with the ``min_count`` parameter. For example, if
you'd like the sum of an empty series to be NaN, pass ``min_count=1``.
>>> pd.Series([]).sum(min_count=1)
nan
Thanks to the ``skipna`` parameter, ``min_count`` handles all-NA and
empty series identically.
>>> pd.Series([np.nan]).sum()
0.0
>>> pd.Series([np.nan]).sum(min_count=1)
nan"""
_max_examples = _shared_docs["stat_func_example"].format(
stat_func="max", verb="Max", default_output=8, level_output_0=4, level_output_1=8
)
_min_examples = _shared_docs["stat_func_example"].format(
stat_func="min", verb="Min", default_output=0, level_output_0=2, level_output_1=0
)
_stat_func_see_also = """
See Also
--------
Series.sum : Return the sum.
Series.min : Return the minimum.
Series.max : Return the maximum.
Series.idxmin : Return the index of the minimum.
Series.idxmax : Return the index of the maximum.
DataFrame.sum : Return the sum over the requested axis.
DataFrame.min : Return the minimum over the requested axis.
DataFrame.max : Return the maximum over the requested axis.
DataFrame.idxmin : Return the index of the minimum over the requested axis.
DataFrame.idxmax : Return the index of the maximum over the requested axis."""
_prod_examples = """
Examples
--------
By default, the product of an empty or all-NA Series is ``1``
>>> pd.Series([]).prod()
1.0
This can be controlled with the ``min_count`` parameter
>>> pd.Series([]).prod(min_count=1)
nan
Thanks to the ``skipna`` parameter, ``min_count`` handles all-NA and
empty series identically.
>>> pd.Series([np.nan]).prod()
1.0
>>> pd.Series([np.nan]).prod(min_count=1)
nan"""
_min_count_stub = """\
min_count : int, default 0
The required number of valid values to perform the operation. If fewer than
``min_count`` non-NA values are present the result will be NA.
.. versionadded:: 0.22.0
Added with the default being 0. This means the sum of an all-NA
or empty Series is 0, and the product of an all-NA or empty
Series is 1.
"""
def _make_min_count_stat_function(
cls, name, name1, name2, axis_descr, desc, f, see_also: str = "", examples: str = ""
):
@Substitution(
desc=desc,
name1=name1,
name2=name2,
axis_descr=axis_descr,
min_count=_min_count_stub,
see_also=see_also,
examples=examples,
)
@Appender(_num_doc)
def stat_func(
self,
axis=None,
skipna=None,
level=None,
numeric_only=None,
min_count=0,
**kwargs,
):
if name == "sum":
nv.validate_sum(tuple(), kwargs)
elif name == "prod":
nv.validate_prod(tuple(), kwargs)
else:
nv.validate_stat_func(tuple(), kwargs, fname=name)
if skipna is None:
skipna = True
if axis is None:
axis = self._stat_axis_number
if level is not None:
return self._agg_by_level(
name, axis=axis, level=level, skipna=skipna, min_count=min_count
)
return self._reduce(
f,
name,
axis=axis,
skipna=skipna,
numeric_only=numeric_only,
min_count=min_count,
)
return set_function_name(stat_func, name, cls)
def _make_stat_function(
cls, name, name1, name2, axis_descr, desc, f, see_also: str = "", examples: str = ""
):
@Substitution(
desc=desc,
name1=name1,
name2=name2,
axis_descr=axis_descr,
min_count="",
see_also=see_also,
examples=examples,
)
@Appender(_num_doc)
def stat_func(
self, axis=None, skipna=None, level=None, numeric_only=None, **kwargs
):
if name == "median":
nv.validate_median(tuple(), kwargs)
else:
nv.validate_stat_func(tuple(), kwargs, fname=name)
if skipna is None:
skipna = True
if axis is None:
axis = self._stat_axis_number
if level is not None:
return self._agg_by_level(name, axis=axis, level=level, skipna=skipna)
return self._reduce(
f, name, axis=axis, skipna=skipna, numeric_only=numeric_only
)
return set_function_name(stat_func, name, cls)
def _make_stat_function_ddof(cls, name, name1, name2, axis_descr, desc, f):
@Substitution(desc=desc, name1=name1, name2=name2, axis_descr=axis_descr)
@Appender(_num_ddof_doc)
def stat_func(
self, axis=None, skipna=None, level=None, ddof=1, numeric_only=None, **kwargs
):
nv.validate_stat_ddof_func(tuple(), kwargs, fname=name)
if skipna is None:
skipna = True
if axis is None:
axis = self._stat_axis_number
if level is not None:
return self._agg_by_level(
name, axis=axis, level=level, skipna=skipna, ddof=ddof
)
return self._reduce(
f, name, axis=axis, numeric_only=numeric_only, skipna=skipna, ddof=ddof
)
return set_function_name(stat_func, name, cls)
def _make_cum_function(
cls,
name,
name1,
name2,
axis_descr,
desc,
accum_func,
accum_func_name,
mask_a,
mask_b,
examples,
):
@Substitution(
desc=desc,
name1=name1,
name2=name2,
axis_descr=axis_descr,
accum_func_name=accum_func_name,
examples=examples,
)
@Appender(_cnum_doc)
def cum_func(self, axis=None, skipna=True, *args, **kwargs):
skipna = nv.validate_cum_func_with_skipna(skipna, args, kwargs, name)
if axis is None:
axis = self._stat_axis_number
else:
axis = self._get_axis_number(axis)
if axis == 1:
return cum_func(self.T, axis=0, skipna=skipna, *args, **kwargs).T
def na_accum_func(blk_values):
# We will be applying this function to block values
if blk_values.dtype.kind in ["m", "M"]:
# GH#30460, GH#29058
# numpy 1.18 started sorting NaTs at the end instead of beginning,
# so we need to work around to maintain backwards-consistency.
orig_dtype = blk_values.dtype
# We need to define mask before masking NaTs
mask = isna(blk_values)
if accum_func == np.minimum.accumulate:
# Note: the accum_func comparison fails as an "is" comparison
y = blk_values.view("i8")
y[mask] = np.iinfo(np.int64).max
changed = True
else:
y = blk_values
changed = False
result = accum_func(y.view("i8"), axis)
if skipna:
np.putmask(result, mask, iNaT)
elif accum_func == np.minimum.accumulate:
# Restore NaTs that we masked previously
nz = (~np.asarray(mask)).nonzero()[0]
if len(nz):
# everything up to the first non-na entry stays NaT
result[: nz[0]] = iNaT
if changed:
# restore NaT elements
y[mask] = iNaT # TODO: could try/finally for this?
if isinstance(blk_values, np.ndarray):
result = result.view(orig_dtype)
else:
# DatetimeArray
result = type(blk_values)._from_sequence(result, dtype=orig_dtype)
elif skipna and not issubclass(
blk_values.dtype.type, (np.integer, np.bool_)
):
vals = blk_values.copy().T
mask = isna(vals)
np.putmask(vals, mask, mask_a)
result = accum_func(vals, axis)
np.putmask(result, mask, mask_b)
else:
result = accum_func(blk_values.T, axis)
# transpose back for ndarray, not for EA
return result.T if hasattr(result, "T") else result
result = self._data.apply(na_accum_func)
d = self._construct_axes_dict()
d["copy"] = False
return self._constructor(result, **d).__finalize__(self)
return set_function_name(cum_func, name, cls)
def _make_logical_function(
cls, name, name1, name2, axis_descr, desc, f, see_also, examples, empty_value
):
@Substitution(
desc=desc,
name1=name1,
name2=name2,
axis_descr=axis_descr,
see_also=see_also,
examples=examples,
empty_value=empty_value,
)
@Appender(_bool_doc)
def logical_func(self, axis=0, bool_only=None, skipna=True, level=None, **kwargs):
nv.validate_logical_func(tuple(), kwargs, fname=name)
if level is not None:
if bool_only is not None:
raise NotImplementedError(
"Option bool_only is not implemented with option level."
)
return self._agg_by_level(name, axis=axis, level=level, skipna=skipna)
return self._reduce(
f,
name,
axis=axis,
skipna=skipna,
numeric_only=bool_only,
filter_type="bool",
)
return set_function_name(logical_func, name, cls)
import collections
from datetime import timedelta
import functools
import gc
import json
import operator
import pickle
import re
from textwrap import dedent
from typing import (
TYPE_CHECKING,
Any,
Callable,
Dict,
FrozenSet,
Hashable,
List,
Mapping,
Optional,
Sequence,
Set,
Tuple,
Type,
Union,
)
import warnings
import weakref
import numpy as np
from pandas._config import config
from pandas._libs import Timestamp, iNaT, lib
from pandas._typing import (
Axis,
Dtype,
FilePathOrBuffer,
FrameOrSeries,
JSONSerializable,
Label,
Level,
Renamer,
)
from pandas.compat import set_function_name
from pandas.compat._optional import import_optional_dependency
from pandas.compat.numpy import function as nv
from pandas.errors import AbstractMethodError
from pandas.util._decorators import (
Appender,
Substitution,
doc,
rewrite_axis_style_signature,
)
from pandas.util._validators import (
validate_bool_kwarg,
validate_fillna_kwargs,
validate_percentile,
)
from pandas.core.dtypes.common import (
ensure_int64,
ensure_object,
ensure_str,
is_bool,
is_bool_dtype,
is_datetime64_any_dtype,
is_datetime64tz_dtype,
is_dict_like,
is_extension_array_dtype,
is_float,
is_integer,
is_list_like,
is_number,
is_numeric_dtype,
is_object_dtype,
is_period_arraylike,
is_re_compilable,
is_scalar,
is_timedelta64_dtype,
pandas_dtype,
)
from pandas.core.dtypes.generic import ABCDataFrame, ABCSeries
from pandas.core.dtypes.inference import is_hashable
from pandas.core.dtypes.missing import isna, notna
import pandas as pd
from pandas.core import missing, nanops
import pandas.core.algorithms as algos
from pandas.core.base import PandasObject, SelectionMixin
import pandas.core.common as com
from pandas.core.construction import create_series_with_explicit_dtype
from pandas.core.indexes.api import (
Index,
InvalidIndexError,
MultiIndex,
RangeIndex,
ensure_index,
)
from pandas.core.indexes.datetimes import DatetimeIndex
from pandas.core.indexes.period import Period, PeriodIndex
import pandas.core.indexing as indexing
from pandas.core.internals import BlockManager
from pandas.core.missing import find_valid_index
from pandas.core.ops import _align_method_FRAME
from pandas.io.formats import format as fmt
from pandas.io.formats.format import DataFrameFormatter, format_percentiles
from pandas.io.formats.printing import pprint_thing
from pandas.tseries.frequencies import to_offset
if TYPE_CHECKING:
from pandas.core.resample import Resampler
# goal is to be able to define the docs close to function, while still being
# able to share
_shared_docs: Dict[str, str] = dict()
_shared_doc_kwargs = dict(
axes="keywords for axes",
klass="Series/DataFrame",
axes_single_arg="int or labels for object",
args_transpose="axes to permute (int or label for object)",
optional_by="""
by : str or list of str
Name or list of names to sort by""",
)
def _single_replace(self, to_replace, method, inplace, limit):
"""
Replaces values in a Series using the fill method specified when no
replacement value is given in the replace method
"""
if self.ndim != 1:
raise TypeError(
f"cannot replace {to_replace} with method {method} on a "
f"{type(self).__name__}"
)
orig_dtype = self.dtype
result = self if inplace else self.copy()
fill_f = missing.get_fill_func(method)
mask = missing.mask_missing(result.values, to_replace)
values = fill_f(result.values, limit=limit, mask=mask)
if values.dtype == orig_dtype and inplace:
return
result = pd.Series(values, index=self.index, dtype=self.dtype).__finalize__(self)
if inplace:
self._update_inplace(result._data)
return
return result
bool_t = bool # Need alias because NDFrame has def bool:
class NDFrame(PandasObject, SelectionMixin, indexing.IndexingMixin):
"""
N-dimensional analogue of DataFrame. Store multi-dimensional in a
size-mutable, labeled data structure
Parameters
----------
data : BlockManager
axes : list
copy : bool, default False
"""
_internal_names: List[str] = [
"_data",
"_cacher",
"_item_cache",
"_cache",
"_is_copy",
"_subtyp",
"_name",
"_index",
"_default_kind",
"_default_fill_value",
"_metadata",
"__array_struct__",
"__array_interface__",
]
_internal_names_set: Set[str] = set(_internal_names)
_accessors: Set[str] = set()
_deprecations: FrozenSet[str] = frozenset(["get_values"])
_metadata: List[str] = []
_is_copy = None
_data: BlockManager
_attrs: Dict[Optional[Hashable], Any]
_typ: str
# ----------------------------------------------------------------------
# Constructors
def __init__(
self,
data: BlockManager,
axes: Optional[List[Index]] = None,
copy: bool = False,
dtype: Optional[Dtype] = None,
attrs: Optional[Mapping[Optional[Hashable], Any]] = None,
fastpath: bool = False,
):
if not fastpath:
if dtype is not None:
data = data.astype(dtype)
elif copy:
data = data.copy()
if axes is not None:
for i, ax in enumerate(axes):
data = data.reindex_axis(ax, axis=i)
object.__setattr__(self, "_is_copy", None)
object.__setattr__(self, "_data", data)
object.__setattr__(self, "_item_cache", {})
if attrs is None:
attrs = {}
else:
attrs = dict(attrs)
object.__setattr__(self, "_attrs", attrs)
def _init_mgr(self, mgr, axes=None, dtype=None, copy=False):
""" passed a manager and a axes dict """
for a, axe in axes.items():
if axe is not None:
mgr = mgr.reindex_axis(
axe, axis=self._get_block_manager_axis(a), copy=False
)
# make a copy if explicitly requested
if copy:
mgr = mgr.copy()
if dtype is not None:
# avoid further copies if we can
if len(mgr.blocks) > 1 or mgr.blocks[0].values.dtype != dtype:
mgr = mgr.astype(dtype=dtype)
return mgr
# ----------------------------------------------------------------------
@property
def attrs(self) -> Dict[Optional[Hashable], Any]:
"""
Dictionary of global attributes on this object.
.. warning::
attrs is experimental and may change without warning.
"""
if self._attrs is None:
self._attrs = {}
return self._attrs
@attrs.setter
def attrs(self, value: Mapping[Optional[Hashable], Any]) -> None:
self._attrs = dict(value)
def _validate_dtype(self, dtype):
""" validate the passed dtype """
if dtype is not None:
dtype = pandas_dtype(dtype)
# a compound dtype
if dtype.kind == "V":
raise NotImplementedError(
"compound dtypes are not implemented "
f"in the {type(self).__name__} constructor"
)
return dtype
# ----------------------------------------------------------------------
# Construction
@property
def _constructor(self: FrameOrSeries) -> Type[FrameOrSeries]:
"""
Used when a manipulation result has the same dimensions as the
original.
"""
raise AbstractMethodError(self)
@property
def _constructor_sliced(self):
"""
Used when a manipulation result has one lower dimension(s) as the
original, such as DataFrame single columns slicing.
"""
raise AbstractMethodError(self)
@property
def _constructor_expanddim(self):
"""
Used when a manipulation result has one higher dimension as the
original, such as Series.to_frame()
"""
raise NotImplementedError
# ----------------------------------------------------------------------
# Axis
_AXIS_ALIASES = {"rows": 0}
_AXIS_IALIASES = {0: "rows"}
_stat_axis_number = 0
_stat_axis_name = "index"
_ix = None
_AXIS_ORDERS: List[str]
_AXIS_NUMBERS: Dict[str, int]
_AXIS_NAMES: Dict[int, str]
_AXIS_REVERSED: bool
_info_axis_number: int
_info_axis_name: str
_AXIS_LEN: int
def _construct_axes_dict(self, axes=None, **kwargs):
"""Return an axes dictionary for myself."""
d = {a: self._get_axis(a) for a in (axes or self._AXIS_ORDERS)}
d.update(kwargs)
return d
def _construct_axes_from_arguments(
self, args, kwargs, require_all: bool = False, sentinel=None
):
"""
Construct and returns axes if supplied in args/kwargs.
If require_all, raise if all axis arguments are not supplied
return a tuple of (axes, kwargs).
sentinel specifies the default parameter when an axis is not
supplied; useful to distinguish when a user explicitly passes None
in scenarios where None has special meaning.
"""
# construct the args
args = list(args)
for a in self._AXIS_ORDERS:
# look for a argument by position
if a not in kwargs:
try:
kwargs[a] = args.pop(0)
except IndexError:
if require_all:
raise TypeError("not enough/duplicate arguments specified!")
axes = {a: kwargs.pop(a, sentinel) for a in self._AXIS_ORDERS}
return axes, kwargs
@classmethod
def _get_axis_number(cls, axis):
axis = cls._AXIS_ALIASES.get(axis, axis)
if is_integer(axis):
if axis in cls._AXIS_NAMES:
return axis
else:
try:
return cls._AXIS_NUMBERS[axis]
except KeyError:
pass
raise ValueError(f"No axis named {axis} for object type {cls}")
@classmethod
def _get_axis_name(cls, axis):
axis = cls._AXIS_ALIASES.get(axis, axis)
if isinstance(axis, str):
if axis in cls._AXIS_NUMBERS:
return axis
else:
try:
return cls._AXIS_NAMES[axis]
except KeyError:
pass
raise ValueError(f"No axis named {axis} for object type {cls}")
def _get_axis(self, axis):
name = self._get_axis_name(axis)
return getattr(self, name)
@classmethod
def _get_block_manager_axis(cls, axis):
"""Map the axis to the block_manager axis."""
axis = cls._get_axis_number(axis)
if cls._AXIS_REVERSED:
m = cls._AXIS_LEN - 1
return m - axis
return axis
def _get_axis_resolvers(self, axis: str) -> Dict[str, ABCSeries]:
# index or columns
axis_index = getattr(self, axis)
d = dict()
prefix = axis[0]
for i, name in enumerate(axis_index.names):
if name is not None:
key = level = name
else:
# prefix with 'i' or 'c' depending on the input axis
# e.g., you must do ilevel_0 for the 0th level of an unnamed
# multiiindex
key = f"{prefix}level_{i}"
level = i
level_values = axis_index.get_level_values(level)
s = level_values.to_series()
s.index = axis_index
d[key] = s
# put the index/columns itself in the dict
if isinstance(axis_index, MultiIndex):
dindex = axis_index
else:
dindex = axis_index.to_series()
d[axis] = dindex
return d
def _get_index_resolvers(self) -> Dict[str, ABCSeries]:
from pandas.core.computation.parsing import clean_column_name
d: Dict[str, ABCSeries] = {}
for axis_name in self._AXIS_ORDERS:
d.update(self._get_axis_resolvers(axis_name))
return {clean_column_name(k): v for k, v in d.items() if not isinstance(k, int)}
def _get_cleaned_column_resolvers(self) -> Dict[str, ABCSeries]:
"""
Return the special character free column resolvers of a dataframe.
Column names with special characters are 'cleaned up' so that they can
be referred to by backtick quoting.
Used in :meth:`DataFrame.eval`.
"""
from pandas.core.computation.parsing import clean_column_name
if isinstance(self, ABCSeries):
return {clean_column_name(self.name): self}
return {
clean_column_name(k): v for k, v in self.items() if not isinstance(k, int)
}
@property
def _info_axis(self):
return getattr(self, self._info_axis_name)
@property
def _stat_axis(self):
return getattr(self, self._stat_axis_name)
@property
def shape(self) -> Tuple[int, ...]:
"""
Return a tuple of axis dimensions
"""
return tuple(len(self._get_axis(a)) for a in self._AXIS_ORDERS)
@property
def axes(self) -> List[Index]:
"""
Return index label(s) of the internal NDFrame
"""
# we do it this way because if we have reversed axes, then
# the block manager shows then reversed
return [self._get_axis(a) for a in self._AXIS_ORDERS]
@property
def ndim(self) -> int:
"""
Return an int representing the number of axes / array dimensions.
Return 1 if Series. Otherwise return 2 if DataFrame.
See Also
--------
ndarray.ndim : Number of array dimensions.
Examples
--------
>>> s = pd.Series({'a': 1, 'b': 2, 'c': 3})
>>> s.ndim
1
>>> df = pd.DataFrame({'col1': [1, 2], 'col2': [3, 4]})
>>> df.ndim
2
"""
return self._data.ndim
@property
def size(self):
"""
Return an int representing the number of elements in this object.
Return the number of rows if Series. Otherwise return the number of
rows times number of columns if DataFrame.
See Also
--------
ndarray.size : Number of elements in the array.
Examples
--------
>>> s = pd.Series({'a': 1, 'b': 2, 'c': 3})
>>> s.size
3
>>> df = pd.DataFrame({'col1': [1, 2], 'col2': [3, 4]})
>>> df.size
4
"""
return np.prod(self.shape)
@property
def _selected_obj(self: FrameOrSeries) -> FrameOrSeries:
""" internal compat with SelectionMixin """
return self
@property
def _obj_with_exclusions(self: FrameOrSeries) -> FrameOrSeries:
""" internal compat with SelectionMixin """
return self
def set_axis(self, labels, axis=0, inplace=False):
"""
Assign desired index to given axis.
Indexes for%(extended_summary_sub)s row labels can be changed by assigning
a list-like or Index.
.. versionchanged:: 0.21.0
The signature is now `labels` and `axis`, consistent with
the rest of pandas API. Previously, the `axis` and `labels`
arguments were respectively the first and second positional
arguments.
Parameters
----------
labels : list-like, Index
The values for the new index.
axis : %(axes_single_arg)s, default 0
The axis to update. The value 0 identifies the rows%(axis_description_sub)s.
inplace : bool, default False
Whether to return a new %(klass)s instance.
Returns
-------
renamed : %(klass)s or None
An object of type %(klass)s if inplace=False, None otherwise.
See Also
--------
%(klass)s.rename_axis : Alter the name of the index%(see_also_sub)s.
"""
if inplace:
setattr(self, self._get_axis_name(axis), labels)
else:
obj = self.copy()
obj.set_axis(labels, axis=axis, inplace=True)
return obj
def _set_axis(self, axis, labels) -> None:
self._data.set_axis(axis, labels)
self._clear_item_cache()
def swapaxes(self: FrameOrSeries, axis1, axis2, copy=True) -> FrameOrSeries:
"""
Interchange axes and swap values axes appropriately.
Returns
-------
y : same as input
"""
i = self._get_axis_number(axis1)
j = self._get_axis_number(axis2)
if i == j:
if copy:
return self.copy()
return self
mapping = {i: j, j: i}
new_axes = (self._get_axis(mapping.get(k, k)) for k in range(self._AXIS_LEN))
new_values = self.values.swapaxes(i, j)
if copy:
new_values = new_values.copy()
return self._constructor(new_values, *new_axes).__finalize__(self)
def droplevel(self: FrameOrSeries, level, axis=0) -> FrameOrSeries:
"""
Return DataFrame with requested index / column level(s) removed.
.. versionadded:: 0.24.0
Parameters
----------
level : int, str, or list-like
If a string is given, must be the name of a level
If list-like, elements must be names or positional indexes
of levels.
axis : {0 or 'index', 1 or 'columns'}, default 0
Returns
-------
DataFrame
DataFrame with requested index / column level(s) removed.
Examples
--------
>>> df = pd.DataFrame([
... [1, 2, 3, 4],
... [5, 6, 7, 8],
... [9, 10, 11, 12]
... ]).set_index([0, 1]).rename_axis(['a', 'b'])
>>> df.columns = pd.MultiIndex.from_tuples([
... ('c', 'e'), ('d', 'f')
... ], names=['level_1', 'level_2'])
>>> df
level_1 c d
level_2 e f
a b
1 2 3 4
5 6 7 8
9 10 11 12
>>> df.droplevel('a')
level_1 c d
level_2 e f
b
2 3 4
6 7 8
10 11 12
>>> df.droplevel('level2', axis=1)
level_1 c d
a b
1 2 3 4
5 6 7 8
9 10 11 12
"""
labels = self._get_axis(axis)
new_labels = labels.droplevel(level)
result = self.set_axis(new_labels, axis=axis, inplace=False)
return result
def pop(self: FrameOrSeries, item) -> FrameOrSeries:
"""
Return item and drop from frame. Raise KeyError if not found.
Parameters
----------
item : str
Label of column to be popped.
Returns
-------
Series
Examples
--------
>>> df = pd.DataFrame([('falcon', 'bird', 389.0),
... ('parrot', 'bird', 24.0),
... ('lion', 'mammal', 80.5),
... ('monkey', 'mammal', np.nan)],
... columns=('name', 'class', 'max_speed'))
>>> df
name class max_speed
0 falcon bird 389.0
1 parrot bird 24.0
2 lion mammal 80.5
3 monkey mammal NaN
>>> df.pop('class')
0 bird
1 bird
2 mammal
3 mammal
Name: class, dtype: object
>>> df
name max_speed
0 falcon 389.0
1 parrot 24.0
2 lion 80.5
3 monkey NaN
"""
result = self[item]
del self[item]
try:
result._reset_cacher()
except AttributeError:
pass
return result
def squeeze(self, axis=None):
"""
Squeeze 1 dimensional axis objects into scalars.
Series or DataFrames with a single element are squeezed to a scalar.
DataFrames with a single column or a single row are squeezed to a
Series. Otherwise the object is unchanged.
This method is most useful when you don't know if your
object is a Series or DataFrame, but you do know it has just a single
column. In that case you can safely call `squeeze` to ensure you have a
Series.
Parameters
----------
axis : {0 or 'index', 1 or 'columns', None}, default None
A specific axis to squeeze. By default, all length-1 axes are
squeezed.
Returns
-------
DataFrame, Series, or scalar
The projection after squeezing `axis` or all the axes.
See Also
--------
Series.iloc : Integer-location based indexing for selecting scalars.
DataFrame.iloc : Integer-location based indexing for selecting Series.
Series.to_frame : Inverse of DataFrame.squeeze for a
single-column DataFrame.
Examples
--------
>>> primes = pd.Series([2, 3, 5, 7])
Slicing might produce a Series with a single value:
>>> even_primes = primes[primes % 2 == 0]
>>> even_primes
0 2
dtype: int64
>>> even_primes.squeeze()
2
Squeezing objects with more than one value in every axis does nothing:
>>> odd_primes = primes[primes % 2 == 1]
>>> odd_primes
1 3
2 5
3 7
dtype: int64
>>> odd_primes.squeeze()
1 3
2 5
3 7
dtype: int64
Squeezing is even more effective when used with DataFrames.
>>> df = pd.DataFrame([[1, 2], [3, 4]], columns=['a', 'b'])
>>> df
a b
0 1 2
1 3 4
Slicing a single column will produce a DataFrame with the columns
having only one value:
>>> df_a = df[['a']]
>>> df_a
a
0 1
1 3
So the columns can be squeezed down, resulting in a Series:
>>> df_a.squeeze('columns')
0 1
1 3
Name: a, dtype: int64
Slicing a single row from a single column will produce a single
scalar DataFrame:
>>> df_0a = df.loc[df.index < 1, ['a']]
>>> df_0a
a
0 1
Squeezing the rows produces a single scalar Series:
>>> df_0a.squeeze('rows')
a 1
Name: 0, dtype: int64
Squeezing all axes will project directly into a scalar:
>>> df_0a.squeeze()
1
"""
axis = self._AXIS_NAMES if axis is None else (self._get_axis_number(axis),)
return self.iloc[
tuple(
0 if i in axis and len(a) == 1 else slice(None)
for i, a in enumerate(self.axes)
)
]
# ----------------------------------------------------------------------
# Rename
def rename(
self: FrameOrSeries,
mapper: Optional[Renamer] = None,
*,
index: Optional[Renamer] = None,
columns: Optional[Renamer] = None,
axis: Optional[Axis] = None,
copy: bool = True,
inplace: bool = False,
level: Optional[Level] = None,
errors: str = "ignore",
) -> Optional[FrameOrSeries]:
"""
Alter axes input function or functions. Function / dict values must be
unique (1-to-1). Labels not contained in a dict / Series will be left
as-is. Extra labels listed don't throw an error. Alternatively, change
``Series.name`` with a scalar value (Series only).
Parameters
----------
%(axes)s : scalar, list-like, dict-like or function, optional
Scalar or list-like will alter the ``Series.name`` attribute,
and raise on DataFrame.
dict-like or functions are transformations to apply to
that axis' values
copy : bool, default True
Also copy underlying data.
inplace : bool, default False
Whether to return a new %(klass)s. If True then value of copy is
ignored.
level : int or level name, default None
In case of a MultiIndex, only rename labels in the specified
level.
errors : {'ignore', 'raise'}, default 'ignore'
If 'raise', raise a `KeyError` when a dict-like `mapper`, `index`,
or `columns` contains labels that are not present in the Index
being transformed.
If 'ignore', existing keys will be renamed and extra keys will be
ignored.
Returns
-------
renamed : %(klass)s (new object)
Raises
------
KeyError
If any of the labels is not found in the selected axis and
"errors='raise'".
See Also
--------
NDFrame.rename_axis
Examples
--------
>>> s = pd.Series([1, 2, 3])
>>> s
0 1
1 2
2 3
dtype: int64
>>> s.rename("my_name") # scalar, changes Series.name
0 1
1 2
2 3
Name: my_name, dtype: int64
>>> s.rename(lambda x: x ** 2) # function, changes labels
0 1
1 2
4 3
dtype: int64
>>> s.rename({1: 3, 2: 5}) # mapping, changes labels
0 1
3 2
5 3
dtype: int64
Since ``DataFrame`` doesn't have a ``.name`` attribute,
only mapping-type arguments are allowed.
>>> df = pd.DataFrame({"A": [1, 2, 3], "B": [4, 5, 6]})
>>> df.rename(2)
Traceback (most recent call last):
...
TypeError: 'int' object is not callable
``DataFrame.rename`` supports two calling conventions
* ``(index=index_mapper, columns=columns_mapper, ...)``
* ``(mapper, axis={'index', 'columns'}, ...)``
We *highly* recommend using keyword arguments to clarify your
intent.
>>> df.rename(index=str, columns={"A": "a", "B": "c"})
a c
0 1 4
1 2 5
2 3 6
>>> df.rename(index=str, columns={"A": "a", "C": "c"})
a B
0 1 4
1 2 5
2 3 6
Using axis-style parameters
>>> df.rename(str.lower, axis='columns')
a b
0 1 4
1 2 5
2 3 6
>>> df.rename({1: 2, 2: 4}, axis='index')
A B
0 1 4
2 2 5
4 3 6
See the :ref:`user guide <basics.rename>` for more.
"""
if mapper is None and index is None and columns is None:
raise TypeError("must pass an index to rename")
if index is not None or columns is not None:
if axis is not None:
raise TypeError(
"Cannot specify both 'axis' and any of 'index' or 'columns'"
)
elif mapper is not None:
raise TypeError(
"Cannot specify both 'mapper' and any of 'index' or 'columns'"
)
else:
# use the mapper argument
if axis and self._get_axis_number(axis) == 1:
columns = mapper
else:
index = mapper
result = self if inplace else self.copy(deep=copy)
for axis_no, replacements in enumerate((index, columns)):
if replacements is None:
continue
ax = self._get_axis(axis_no)
baxis = self._get_block_manager_axis(axis_no)
f = com.get_rename_function(replacements)
if level is not None:
level = ax._get_level_number(level)
# GH 13473
if not callable(replacements):
indexer = ax.get_indexer_for(replacements)
if errors == "raise" and len(indexer[indexer == -1]):
missing_labels = [
label
for index, label in enumerate(replacements)
if indexer[index] == -1
]
raise KeyError(f"{missing_labels} not found in axis")
result._data = result._data.rename_axis(
f, axis=baxis, copy=copy, level=level
)
result._clear_item_cache()
if inplace:
self._update_inplace(result._data)
return None
else:
return result.__finalize__(self)
@rewrite_axis_style_signature("mapper", [("copy", True), ("inplace", False)])
def rename_axis(self, mapper=lib.no_default, **kwargs):
"""
Set the name of the axis for the index or columns.
Parameters
----------
mapper : scalar, list-like, optional
Value to set the axis name attribute.
index, columns : scalar, list-like, dict-like or function, optional
A scalar, list-like, dict-like or functions transformations to
apply to that axis' values.
Use either ``mapper`` and ``axis`` to
specify the axis to target with ``mapper``, or ``index``
and/or ``columns``.
.. versionchanged:: 0.24.0
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to rename.
copy : bool, default True
Also copy underlying data.
inplace : bool, default False
Modifies the object directly, instead of creating a new Series
or DataFrame.
Returns
-------
Series, DataFrame, or None
The same type as the caller or None if `inplace` is True.
See Also
--------
Series.rename : Alter Series index labels or name.
DataFrame.rename : Alter DataFrame index labels or name.
Index.rename : Set new names on index.
Notes
-----
``DataFrame.rename_axis`` supports two calling conventions
* ``(index=index_mapper, columns=columns_mapper, ...)``
* ``(mapper, axis={'index', 'columns'}, ...)``
The first calling convention will only modify the names of
the index and/or the names of the Index object that is the columns.
In this case, the parameter ``copy`` is ignored.
The second calling convention will modify the names of the
the corresponding index if mapper is a list or a scalar.
However, if mapper is dict-like or a function, it will use the
deprecated behavior of modifying the axis *labels*.
We *highly* recommend using keyword arguments to clarify your
intent.
Examples
--------
**Series**
>>> s = pd.Series(["dog", "cat", "monkey"])
>>> s
0 dog
1 cat
2 monkey
dtype: object
>>> s.rename_axis("animal")
animal
0 dog
1 cat
2 monkey
dtype: object
**DataFrame**
>>> df = pd.DataFrame({"num_legs": [4, 4, 2],
... "num_arms": [0, 0, 2]},
... ["dog", "cat", "monkey"])
>>> df
num_legs num_arms
dog 4 0
cat 4 0
monkey 2 2
>>> df = df.rename_axis("animal")
>>> df
num_legs num_arms
animal
dog 4 0
cat 4 0
monkey 2 2
>>> df = df.rename_axis("limbs", axis="columns")
>>> df
limbs num_legs num_arms
animal
dog 4 0
cat 4 0
monkey 2 2
**MultiIndex**
>>> df.index = pd.MultiIndex.from_product([['mammal'],
... ['dog', 'cat', 'monkey']],
... names=['type', 'name'])
>>> df
limbs num_legs num_arms
type name
mammal dog 4 0
cat 4 0
monkey 2 2
>>> df.rename_axis(index={'type': 'class'})
limbs num_legs num_arms
class name
mammal dog 4 0
cat 4 0
monkey 2 2
>>> df.rename_axis(columns=str.upper)
LIMBS num_legs num_arms
type name
mammal dog 4 0
cat 4 0
monkey 2 2
"""
axes, kwargs = self._construct_axes_from_arguments(
(), kwargs, sentinel=lib.no_default
)
copy = kwargs.pop("copy", True)
inplace = kwargs.pop("inplace", False)
axis = kwargs.pop("axis", 0)
if axis is not None:
axis = self._get_axis_number(axis)
if kwargs:
raise TypeError(
"rename_axis() got an unexpected keyword "
f'argument "{list(kwargs.keys())[0]}"'
)
inplace = validate_bool_kwarg(inplace, "inplace")
if mapper is not lib.no_default:
# Use v0.23 behavior if a scalar or list
non_mapper = is_scalar(mapper) or (
is_list_like(mapper) and not is_dict_like(mapper)
)
if non_mapper:
return self._set_axis_name(mapper, axis=axis, inplace=inplace)
else:
raise ValueError("Use `.rename` to alter labels with a mapper.")
else:
# Use new behavior. Means that index and/or columns
# is specified
result = self if inplace else self.copy(deep=copy)
for axis in range(self._AXIS_LEN):
v = axes.get(self._AXIS_NAMES[axis])
if v is lib.no_default:
continue
non_mapper = is_scalar(v) or (is_list_like(v) and not is_dict_like(v))
if non_mapper:
newnames = v
else:
f = com.get_rename_function(v)
curnames = self._get_axis(axis).names
newnames = [f(name) for name in curnames]
result._set_axis_name(newnames, axis=axis, inplace=True)
if not inplace:
return result
def _set_axis_name(self, name, axis=0, inplace=False):
"""
Set the name(s) of the axis.
Parameters
----------
name : str or list of str
Name(s) to set.
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to set the label. The value 0 or 'index' specifies index,
and the value 1 or 'columns' specifies columns.
inplace : bool, default False
If `True`, do operation inplace and return None.
.. versionadded:: 0.21.0
Returns
-------
Series, DataFrame, or None
The same type as the caller or `None` if `inplace` is `True`.
See Also
--------
DataFrame.rename : Alter the axis labels of :class:`DataFrame`.
Series.rename : Alter the index labels or set the index name
of :class:`Series`.
Index.rename : Set the name of :class:`Index` or :class:`MultiIndex`.
Examples
--------
>>> df = pd.DataFrame({"num_legs": [4, 4, 2]},
... ["dog", "cat", "monkey"])
>>> df
num_legs
dog 4
cat 4
monkey 2
>>> df._set_axis_name("animal")
num_legs
animal
dog 4
cat 4
monkey 2
>>> df.index = pd.MultiIndex.from_product(
... [["mammal"], ['dog', 'cat', 'monkey']])
>>> df._set_axis_name(["type", "name"])
legs
type name
mammal dog 4
cat 4
monkey 2
"""
axis = self._get_axis_number(axis)
idx = self._get_axis(axis).set_names(name)
inplace = validate_bool_kwarg(inplace, "inplace")
renamed = self if inplace else self.copy()
renamed.set_axis(idx, axis=axis, inplace=True)
if not inplace:
return renamed
# ----------------------------------------------------------------------
# Comparison Methods
def _indexed_same(self, other) -> bool:
return all(
self._get_axis(a).equals(other._get_axis(a)) for a in self._AXIS_ORDERS
)
def equals(self, other):
"""
Test whether two objects contain the same elements.
This function allows two Series or DataFrames to be compared against
each other to see if they have the same shape and elements. NaNs in
the same location are considered equal. The column headers do not
need to have the same type, but the elements within the columns must
be the same dtype.
Parameters
----------
other : Series or DataFrame
The other Series or DataFrame to be compared with the first.
Returns
-------
bool
True if all elements are the same in both objects, False
otherwise.
See Also
--------
Series.eq : Compare two Series objects of the same length
and return a Series where each element is True if the element
in each Series is equal, False otherwise.
DataFrame.eq : Compare two DataFrame objects of the same shape and
return a DataFrame where each element is True if the respective
element in each DataFrame is equal, False otherwise.
testing.assert_series_equal : Raises an AssertionError if left and
right are not equal. Provides an easy interface to ignore
inequality in dtypes, indexes and precision among others.
testing.assert_frame_equal : Like assert_series_equal, but targets
DataFrames.
numpy.array_equal : Return True if two arrays have the same shape
and elements, False otherwise.
Notes
-----
This function requires that the elements have the same dtype as their
respective elements in the other Series or DataFrame. However, the
column labels do not need to have the same type, as long as they are
still considered equal.
Examples
--------
>>> df = pd.DataFrame({1: [10], 2: [20]})
>>> df
1 2
0 10 20
DataFrames df and exactly_equal have the same types and values for
their elements and column labels, which will return True.
>>> exactly_equal = pd.DataFrame({1: [10], 2: [20]})
>>> exactly_equal
1 2
0 10 20
>>> df.equals(exactly_equal)
True
DataFrames df and different_column_type have the same element
types and values, but have different types for the column labels,
which will still return True.
>>> different_column_type = pd.DataFrame({1.0: [10], 2.0: [20]})
>>> different_column_type
1.0 2.0
0 10 20
>>> df.equals(different_column_type)
True
DataFrames df and different_data_type have different types for the
same values for their elements, and will return False even though
their column labels are the same values and types.
>>> different_data_type = pd.DataFrame({1: [10.0], 2: [20.0]})
>>> different_data_type
1 2
0 10.0 20.0
>>> df.equals(different_data_type)
False
"""
if not isinstance(other, self._constructor):
return False
return self._data.equals(other._data)
# -------------------------------------------------------------------------
# Unary Methods
def __neg__(self):
values = com.values_from_object(self)
if is_bool_dtype(values):
arr = operator.inv(values)
elif (
is_numeric_dtype(values)
or is_timedelta64_dtype(values)
or is_object_dtype(values)
):
arr = operator.neg(values)
else:
raise TypeError(f"Unary negative expects numeric dtype, not {values.dtype}")
return self.__array_wrap__(arr)
def __pos__(self):
values = com.values_from_object(self)
if is_bool_dtype(values) or is_period_arraylike(values):
arr = values
elif (
is_numeric_dtype(values)
or is_timedelta64_dtype(values)
or is_object_dtype(values)
):
arr = operator.pos(values)
else:
raise TypeError(f"Unary plus expects numeric dtype, not {values.dtype}")
return self.__array_wrap__(arr)
def __invert__(self):
if not self.size:
# inv fails with 0 len
return self
new_data = self._data.apply(operator.invert)
result = self._constructor(new_data).__finalize__(self)
return result
def __nonzero__(self):
raise ValueError(
f"The truth value of a {type(self).__name__} is ambiguous. "
"Use a.empty, a.bool(), a.item(), a.any() or a.all()."
)
__bool__ = __nonzero__
def bool(self):
"""
Return the bool of a single element PandasObject.
This must be a boolean scalar value, either True or False. Raise a
ValueError if the PandasObject does not have exactly 1 element, or that
element is not boolean
Returns
-------
bool
Same single boolean value converted to bool type.
"""
v = self.squeeze()
if isinstance(v, (bool, np.bool_)):
return bool(v)
elif is_scalar(v):
raise ValueError(
"bool cannot act on a non-boolean single element "
f"{type(self).__name__}"
)
self.__nonzero__()
def __abs__(self: FrameOrSeries) -> FrameOrSeries:
return self.abs()
def __round__(self: FrameOrSeries, decimals: int = 0) -> FrameOrSeries:
return self.round(decimals)
# -------------------------------------------------------------------------
# Label or Level Combination Helpers
#
# A collection of helper methods for DataFrame/Series operations that
# accept a combination of column/index labels and levels. All such
# operations should utilize/extend these methods when possible so that we
# have consistent precedence and validation logic throughout the library.
def _is_level_reference(self, key, axis=0):
"""
Test whether a key is a level reference for a given axis.
To be considered a level reference, `key` must be a string that:
- (axis=0): Matches the name of an index level and does NOT match
a column label.
- (axis=1): Matches the name of a column level and does NOT match
an index label.
Parameters
----------
key : str
Potential level name for the given axis
axis : int, default 0
Axis that levels are associated with (0 for index, 1 for columns)
Returns
-------
is_level : bool
"""
axis = self._get_axis_number(axis)
return (
key is not None
and is_hashable(key)
and key in self.axes[axis].names
and not self._is_label_reference(key, axis=axis)
)
def _is_label_reference(self, key, axis=0) -> bool_t:
"""
Test whether a key is a label reference for a given axis.
To be considered a label reference, `key` must be a string that:
- (axis=0): Matches a column label
- (axis=1): Matches an index label
Parameters
----------
key: str
Potential label name
axis: int, default 0
Axis perpendicular to the axis that labels are associated with
(0 means search for column labels, 1 means search for index labels)
Returns
-------
is_label: bool
"""
axis = self._get_axis_number(axis)
other_axes = (ax for ax in range(self._AXIS_LEN) if ax != axis)
return (
key is not None
and is_hashable(key)
and any(key in self.axes[ax] for ax in other_axes)
)
def _is_label_or_level_reference(self, key: str, axis: int = 0) -> bool_t:
"""
Test whether a key is a label or level reference for a given axis.
To be considered either a label or a level reference, `key` must be a
string that:
- (axis=0): Matches a column label or an index level
- (axis=1): Matches an index label or a column level
Parameters
----------
key: str
Potential label or level name
axis: int, default 0
Axis that levels are associated with (0 for index, 1 for columns)
Returns
-------
is_label_or_level: bool
"""
return self._is_level_reference(key, axis=axis) or self._is_label_reference(
key, axis=axis
)
def _check_label_or_level_ambiguity(self, key, axis: int = 0) -> None:
"""
Check whether `key` is ambiguous.
By ambiguous, we mean that it matches both a level of the input
`axis` and a label of the other axis.
Parameters
----------
key: str or object
Label or level name.
axis: int, default 0
Axis that levels are associated with (0 for index, 1 for columns).
Raises
------
ValueError: `key` is ambiguous
"""
axis = self._get_axis_number(axis)
other_axes = (ax for ax in range(self._AXIS_LEN) if ax != axis)
if (
key is not None
and is_hashable(key)
and key in self.axes[axis].names
and any(key in self.axes[ax] for ax in other_axes)
):
# Build an informative and grammatical warning
level_article, level_type = (
("an", "index") if axis == 0 else ("a", "column")
)
label_article, label_type = (
("a", "column") if axis == 0 else ("an", "index")
)
msg = (
f"'{key}' is both {level_article} {level_type} level and "
f"{label_article} {label_type} label, which is ambiguous."
)
raise ValueError(msg)
def _get_label_or_level_values(self, key: str, axis: int = 0) -> np.ndarray:
"""
Return a 1-D array of values associated with `key`, a label or level
from the given `axis`.
Retrieval logic:
- (axis=0): Return column values if `key` matches a column label.
Otherwise return index level values if `key` matches an index
level.
- (axis=1): Return row values if `key` matches an index label.
Otherwise return column level values if 'key' matches a column
level
Parameters
----------
key: str
Label or level name.
axis: int, default 0
Axis that levels are associated with (0 for index, 1 for columns)
Returns
-------
values: np.ndarray
Raises
------
KeyError
if `key` matches neither a label nor a level
ValueError
if `key` matches multiple labels
FutureWarning
if `key` is ambiguous. This will become an ambiguity error in a
future version
"""
axis = self._get_axis_number(axis)
other_axes = [ax for ax in range(self._AXIS_LEN) if ax != axis]
if self._is_label_reference(key, axis=axis):
self._check_label_or_level_ambiguity(key, axis=axis)
values = self.xs(key, axis=other_axes[0])._values
elif self._is_level_reference(key, axis=axis):
values = self.axes[axis].get_level_values(key)._values
else:
raise KeyError(key)
# Check for duplicates
if values.ndim > 1:
if other_axes and isinstance(self._get_axis(other_axes[0]), MultiIndex):
multi_message = (
"\n"
"For a multi-index, the label must be a "
"tuple with elements corresponding to each level."
)
else:
multi_message = ""
label_axis_name = "column" if axis == 0 else "index"
raise ValueError(
(
f"The {label_axis_name} label '{key}' "
f"is not unique.{multi_message}"
)
)
return values
def _drop_labels_or_levels(self, keys, axis: int = 0):
"""
Drop labels and/or levels for the given `axis`.
For each key in `keys`:
- (axis=0): If key matches a column label then drop the column.
Otherwise if key matches an index level then drop the level.
- (axis=1): If key matches an index label then drop the row.
Otherwise if key matches a column level then drop the level.
Parameters
----------
keys: str or list of str
labels or levels to drop
axis: int, default 0
Axis that levels are associated with (0 for index, 1 for columns)
Returns
-------
dropped: DataFrame
Raises
------
ValueError
if any `keys` match neither a label nor a level
"""
axis = self._get_axis_number(axis)
# Validate keys
keys = com.maybe_make_list(keys)
invalid_keys = [
k for k in keys if not self._is_label_or_level_reference(k, axis=axis)
]
if invalid_keys:
raise ValueError(
(
"The following keys are not valid labels or "
f"levels for axis {axis}: {invalid_keys}"
)
)
# Compute levels and labels to drop
levels_to_drop = [k for k in keys if self._is_level_reference(k, axis=axis)]
labels_to_drop = [k for k in keys if not self._is_level_reference(k, axis=axis)]
# Perform copy upfront and then use inplace operations below.
# This ensures that we always perform exactly one copy.
# ``copy`` and/or ``inplace`` options could be added in the future.
dropped = self.copy()
if axis == 0:
# Handle dropping index levels
if levels_to_drop:
dropped.reset_index(levels_to_drop, drop=True, inplace=True)
# Handle dropping columns labels
if labels_to_drop:
dropped.drop(labels_to_drop, axis=1, inplace=True)
else:
# Handle dropping column levels
if levels_to_drop:
if isinstance(dropped.columns, MultiIndex):
# Drop the specified levels from the MultiIndex
dropped.columns = dropped.columns.droplevel(levels_to_drop)
else:
# Drop the last level of Index by replacing with
# a RangeIndex
dropped.columns = RangeIndex(dropped.columns.size)
# Handle dropping index labels
if labels_to_drop:
dropped.drop(labels_to_drop, axis=0, inplace=True)
return dropped
# ----------------------------------------------------------------------
# Iteration
def __hash__(self):
raise TypeError(
f"{repr(type(self).__name__)} objects are mutable, "
f"thus they cannot be hashed"
)
def __iter__(self):
"""
Iterate over info axis.
Returns
-------
iterator
Info axis as iterator.
"""
return iter(self._info_axis)
# can we get a better explanation of this?
def keys(self):
"""
Get the 'info axis' (see Indexing for more).
This is index for Series, columns for DataFrame.
Returns
-------
Index
Info axis.
"""
return self._info_axis
def items(self):
"""
Iterate over (label, values) on info axis
This is index for Series and columns for DataFrame.
Returns
-------
Generator
"""
for h in self._info_axis:
yield h, self[h]
@Appender(items.__doc__)
def iteritems(self):
return self.items()
def __len__(self) -> int:
"""Returns length of info axis"""
return len(self._info_axis)
def __contains__(self, key) -> bool_t:
"""True if the key is in the info axis"""
return key in self._info_axis
@property
def empty(self) -> bool_t:
"""
Indicator whether DataFrame is empty.
True if DataFrame is entirely empty (no items), meaning any of the
axes are of length 0.
Returns
-------
bool
If DataFrame is empty, return True, if not return False.
See Also
--------
Series.dropna
DataFrame.dropna
Notes
-----
If DataFrame contains only NaNs, it is still not considered empty. See
the example below.
Examples
--------
An example of an actual empty DataFrame. Notice the index is empty:
>>> df_empty = pd.DataFrame({'A' : []})
>>> df_empty
Empty DataFrame
Columns: [A]
Index: []
>>> df_empty.empty
True
If we only have NaNs in our DataFrame, it is not considered empty! We
will need to drop the NaNs to make the DataFrame empty:
>>> df = pd.DataFrame({'A' : [np.nan]})
>>> df
A
0 NaN
>>> df.empty
False
>>> df.dropna().empty
True
"""
return any(len(self._get_axis(a)) == 0 for a in self._AXIS_ORDERS)
# ----------------------------------------------------------------------
# Array Interface
# This is also set in IndexOpsMixin
# GH#23114 Ensure ndarray.__op__(DataFrame) returns NotImplemented
__array_priority__ = 1000
def __array__(self, dtype=None) -> np.ndarray:
return com.values_from_object(self)
def __array_wrap__(self, result, context=None):
result = lib.item_from_zerodim(result)
if is_scalar(result):
# e.g. we get here with np.ptp(series)
# ptp also requires the item_from_zerodim
return result
d = self._construct_axes_dict(self._AXIS_ORDERS, copy=False)
return self._constructor(result, **d).__finalize__(self)
# ideally we would define this to avoid the getattr checks, but
# is slower
# @property
# def __array_interface__(self):
# """ provide numpy array interface method """
# values = self.values
# return dict(typestr=values.dtype.str,shape=values.shape,data=values)
# ----------------------------------------------------------------------
# Picklability
def __getstate__(self) -> Dict[str, Any]:
meta = {k: getattr(self, k, None) for k in self._metadata}
return dict(
_data=self._data,
_typ=self._typ,
_metadata=self._metadata,
attrs=self.attrs,
**meta,
)
def __setstate__(self, state):
if isinstance(state, BlockManager):
self._data = state
elif isinstance(state, dict):
typ = state.get("_typ")
if typ is not None:
attrs = state.get("_attrs", {})
object.__setattr__(self, "_attrs", attrs)
# set in the order of internal names
# to avoid definitional recursion
# e.g. say fill_value needing _data to be
# defined
meta = set(self._internal_names + self._metadata)
for k in list(meta):
if k in state:
v = state[k]
object.__setattr__(self, k, v)
for k, v in state.items():
if k not in meta:
object.__setattr__(self, k, v)
else:
raise NotImplementedError("Pre-0.12 pickles are no longer supported")
elif len(state) == 2:
raise NotImplementedError("Pre-0.12 pickles are no longer supported")
self._item_cache = {}
# ----------------------------------------------------------------------
# Rendering Methods
def __repr__(self) -> str:
# string representation based upon iterating over self
# (since, by definition, `PandasContainers` are iterable)
prepr = f"[{','.join(map(pprint_thing, self))}]"
return f"{type(self).__name__}({prepr})"
def _repr_latex_(self):
"""
Returns a LaTeX representation for a particular object.
Mainly for use with nbconvert (jupyter notebook conversion to pdf).
"""
if config.get_option("display.latex.repr"):
return self.to_latex()
else:
return None
def _repr_data_resource_(self):
"""
Not a real Jupyter special repr method, but we use the same
naming convention.
"""
if config.get_option("display.html.table_schema"):
data = self.head(config.get_option("display.max_rows"))
payload = json.loads(
data.to_json(orient="table"), object_pairs_hook=collections.OrderedDict
)
return payload
# ----------------------------------------------------------------------
# I/O Methods
_shared_docs[
"to_markdown"
] = """
Print %(klass)s in Markdown-friendly format.
.. versionadded:: 1.0.0
Parameters
----------
buf : str, Path or StringIO-like, optional, default None
Buffer to write to. If None, the output is returned as a string.
mode : str, optional
Mode in which file is opened.
**kwargs
These parameters will be passed to `tabulate`.
Returns
-------
str
%(klass)s in Markdown-friendly format.
"""
_shared_docs[
"to_excel"
] = """
Write %(klass)s to an Excel sheet.
To write a single %(klass)s to an Excel .xlsx file it is only necessary to
specify a target file name. To write to multiple sheets it is necessary to
create an `ExcelWriter` object with a target file name, and specify a sheet
in the file to write to.
Multiple sheets may be written to by specifying unique `sheet_name`.
With all data written to the file it is necessary to save the changes.
Note that creating an `ExcelWriter` object with a file name that already
exists will result in the contents of the existing file being erased.
Parameters
----------
excel_writer : str or ExcelWriter object
File path or existing ExcelWriter.
sheet_name : str, default 'Sheet1'
Name of sheet which will contain DataFrame.
na_rep : str, default ''
Missing data representation.
float_format : str, optional
Format string for floating point numbers. For example
``float_format="%%.2f"`` will format 0.1234 to 0.12.
columns : sequence or list of str, optional
Columns to write.
header : bool or list of str, default True
Write out the column names. If a list of string is given it is
assumed to be aliases for the column names.
index : bool, default True
Write row names (index).
index_label : str or sequence, optional
Column label for index column(s) if desired. If not specified, and
`header` and `index` are True, then the index names are used. A
sequence should be given if the DataFrame uses MultiIndex.
startrow : int, default 0
Upper left cell row to dump data frame.
startcol : int, default 0
Upper left cell column to dump data frame.
engine : str, optional
Write engine to use, 'openpyxl' or 'xlsxwriter'. You can also set this
via the options ``io.excel.xlsx.writer``, ``io.excel.xls.writer``, and
``io.excel.xlsm.writer``.
merge_cells : bool, default True
Write MultiIndex and Hierarchical Rows as merged cells.
encoding : str, optional
Encoding of the resulting excel file. Only necessary for xlwt,
other writers support unicode natively.
inf_rep : str, default 'inf'
Representation for infinity (there is no native representation for
infinity in Excel).
verbose : bool, default True
Display more information in the error logs.
freeze_panes : tuple of int (length 2), optional
Specifies the one-based bottommost row and rightmost column that
is to be frozen.
See Also
--------
to_csv : Write DataFrame to a comma-separated values (csv) file.
ExcelWriter : Class for writing DataFrame objects into excel sheets.
read_excel : Read an Excel file into a pandas DataFrame.
read_csv : Read a comma-separated values (csv) file into DataFrame.
Notes
-----
For compatibility with :meth:`~DataFrame.to_csv`,
to_excel serializes lists and dicts to strings before writing.
Once a workbook has been saved it is not possible write further data
without rewriting the whole workbook.
Examples
--------
Create, write to and save a workbook:
>>> df1 = pd.DataFrame([['a', 'b'], ['c', 'd']],
... index=['row 1', 'row 2'],
... columns=['col 1', 'col 2'])
>>> df1.to_excel("output.xlsx") # doctest: +SKIP
To specify the sheet name:
>>> df1.to_excel("output.xlsx",
... sheet_name='Sheet_name_1') # doctest: +SKIP
If you wish to write to more than one sheet in the workbook, it is
necessary to specify an ExcelWriter object:
>>> df2 = df1.copy()
>>> with pd.ExcelWriter('output.xlsx') as writer: # doctest: +SKIP
... df1.to_excel(writer, sheet_name='Sheet_name_1')
... df2.to_excel(writer, sheet_name='Sheet_name_2')
ExcelWriter can also be used to append to an existing Excel file:
>>> with pd.ExcelWriter('output.xlsx',
... mode='a') as writer: # doctest: +SKIP
... df.to_excel(writer, sheet_name='Sheet_name_3')
To set the library that is used to write the Excel file,
you can pass the `engine` keyword (the default engine is
automatically chosen depending on the file extension):
>>> df1.to_excel('output1.xlsx', engine='xlsxwriter') # doctest: +SKIP
"""
@Appender(_shared_docs["to_excel"] % dict(klass="object"))
def to_excel(
self,
excel_writer,
sheet_name="Sheet1",
na_rep="",
float_format=None,
columns=None,
header=True,
index=True,
index_label=None,
startrow=0,
startcol=0,
engine=None,
merge_cells=True,
encoding=None,
inf_rep="inf",
verbose=True,
freeze_panes=None,
) -> None:
df = self if isinstance(self, ABCDataFrame) else self.to_frame()
from pandas.io.formats.excel import ExcelFormatter
formatter = ExcelFormatter(
df,
na_rep=na_rep,
cols=columns,
header=header,
float_format=float_format,
index=index,
index_label=index_label,
merge_cells=merge_cells,
inf_rep=inf_rep,
)
formatter.write(
excel_writer,
sheet_name=sheet_name,
startrow=startrow,
startcol=startcol,
freeze_panes=freeze_panes,
engine=engine,
)
def to_json(
self,
path_or_buf: Optional[FilePathOrBuffer] = None,
orient: Optional[str] = None,
date_format: Optional[str] = None,
double_precision: int = 10,
force_ascii: bool_t = True,
date_unit: str = "ms",
default_handler: Optional[Callable[[Any], JSONSerializable]] = None,
lines: bool_t = False,
compression: Optional[str] = "infer",
index: bool_t = True,
indent: Optional[int] = None,
) -> Optional[str]:
"""
Convert the object to a JSON string.
Note NaN's and None will be converted to null and datetime objects
will be converted to UNIX timestamps.
Parameters
----------
path_or_buf : str or file handle, optional
File path or object. If not specified, the result is returned as
a string.
orient : str
Indication of expected JSON string format.
* Series:
- default is 'index'
- allowed values are: {'split','records','index','table'}.
* DataFrame:
- default is 'columns'
- allowed values are: {'split', 'records', 'index', 'columns',
'values', 'table'}.
* The format of the JSON string:
- 'split' : dict like {'index' -> [index], 'columns' -> [columns],
'data' -> [values]}
- 'records' : list like [{column -> value}, ... , {column -> value}]
- 'index' : dict like {index -> {column -> value}}
- 'columns' : dict like {column -> {index -> value}}
- 'values' : just the values array
- 'table' : dict like {'schema': {schema}, 'data': {data}}
Describing the data, where data component is like ``orient='records'``.
.. versionchanged:: 0.20.0
date_format : {None, 'epoch', 'iso'}
Type of date conversion. 'epoch' = epoch milliseconds,
'iso' = ISO8601. The default depends on the `orient`. For
``orient='table'``, the default is 'iso'. For all other orients,
the default is 'epoch'.
double_precision : int, default 10
The number of decimal places to use when encoding
floating point values.
force_ascii : bool, default True
Force encoded string to be ASCII.
date_unit : str, default 'ms' (milliseconds)
The time unit to encode to, governs timestamp and ISO8601
precision. One of 's', 'ms', 'us', 'ns' for second, millisecond,
microsecond, and nanosecond respectively.
default_handler : callable, default None
Handler to call if object cannot otherwise be converted to a
suitable format for JSON. Should receive a single argument which is
the object to convert and return a serialisable object.
lines : bool, default False
If 'orient' is 'records' write out line delimited json format. Will
throw ValueError if incorrect 'orient' since others are not list
like.
compression : {'infer', 'gzip', 'bz2', 'zip', 'xz', None}
A string representing the compression to use in the output file,
only used when the first argument is a filename. By default, the
compression is inferred from the filename.
.. versionadded:: 0.21.0
.. versionchanged:: 0.24.0
'infer' option added and set to default
index : bool, default True
Whether to include the index values in the JSON string. Not
including the index (``index=False``) is only supported when
orient is 'split' or 'table'.
.. versionadded:: 0.23.0
indent : int, optional
Length of whitespace used to indent each record.
.. versionadded:: 1.0.0
Returns
-------
None or str
If path_or_buf is None, returns the resulting json format as a
string. Otherwise returns None.
See Also
--------
read_json
Notes
-----
The behavior of ``indent=0`` varies from the stdlib, which does not
indent the output but does insert newlines. Currently, ``indent=0``
and the default ``indent=None`` are equivalent in pandas, though this
may change in a future release.
Examples
--------
>>> df = pd.DataFrame([['a', 'b'], ['c', 'd']],
... index=['row 1', 'row 2'],
... columns=['col 1', 'col 2'])
>>> df.to_json(orient='split')
'{"columns":["col 1","col 2"],
"index":["row 1","row 2"],
"data":[["a","b"],["c","d"]]}'
Encoding/decoding a Dataframe using ``'records'`` formatted JSON.
Note that index labels are not preserved with this encoding.
>>> df.to_json(orient='records')
'[{"col 1":"a","col 2":"b"},{"col 1":"c","col 2":"d"}]'
Encoding/decoding a Dataframe using ``'index'`` formatted JSON:
>>> df.to_json(orient='index')
'{"row 1":{"col 1":"a","col 2":"b"},"row 2":{"col 1":"c","col 2":"d"}}'
Encoding/decoding a Dataframe using ``'columns'`` formatted JSON:
>>> df.to_json(orient='columns')
'{"col 1":{"row 1":"a","row 2":"c"},"col 2":{"row 1":"b","row 2":"d"}}'
Encoding/decoding a Dataframe using ``'values'`` formatted JSON:
>>> df.to_json(orient='values')
'[["a","b"],["c","d"]]'
Encoding with Table Schema
>>> df.to_json(orient='table')
'{"schema": {"fields": [{"name": "index", "type": "string"},
{"name": "col 1", "type": "string"},
{"name": "col 2", "type": "string"}],
"primaryKey": "index",
"pandas_version": "0.20.0"},
"data": [{"index": "row 1", "col 1": "a", "col 2": "b"},
{"index": "row 2", "col 1": "c", "col 2": "d"}]}'
"""
from pandas.io import json
if date_format is None and orient == "table":
date_format = "iso"
elif date_format is None:
date_format = "epoch"
config.is_nonnegative_int(indent)
indent = indent or 0
return json.to_json(
path_or_buf=path_or_buf,
obj=self,
orient=orient,
date_format=date_format,
double_precision=double_precision,
force_ascii=force_ascii,
date_unit=date_unit,
default_handler=default_handler,
lines=lines,
compression=compression,
index=index,
indent=indent,
)
def to_hdf(
self,
path_or_buf,
key: str,
mode: str = "a",
complevel: Optional[int] = None,
complib: Optional[str] = None,
append: bool_t = False,
format: Optional[str] = None,
index: bool_t = True,
min_itemsize: Optional[Union[int, Dict[str, int]]] = None,
nan_rep=None,
dropna: Optional[bool_t] = None,
data_columns: Optional[List[str]] = None,
errors: str = "strict",
encoding: str = "UTF-8",
) -> None:
"""
Write the contained data to an HDF5 file using HDFStore.
Hierarchical Data Format (HDF) is self-describing, allowing an
application to interpret the structure and contents of a file with
no outside information. One HDF file can hold a mix of related objects
which can be accessed as a group or as individual objects.
In order to add another DataFrame or Series to an existing HDF file
please use append mode and a different a key.
For more information see the :ref:`user guide <io.hdf5>`.
Parameters
----------
path_or_buf : str or pandas.HDFStore
File path or HDFStore object.
key : str
Identifier for the group in the store.
mode : {'a', 'w', 'r+'}, default 'a'
Mode to open file:
- 'w': write, a new file is created (an existing file with
the same name would be deleted).
- 'a': append, an existing file is opened for reading and
writing, and if the file does not exist it is created.
- 'r+': similar to 'a', but the file must already exist.
complevel : {0-9}, optional
Specifies a compression level for data.
A value of 0 disables compression.
complib : {'zlib', 'lzo', 'bzip2', 'blosc'}, default 'zlib'
Specifies the compression library to be used.
As of v0.20.2 these additional compressors for Blosc are supported
(default if no compressor specified: 'blosc:blosclz'):
{'blosc:blosclz', 'blosc:lz4', 'blosc:lz4hc', 'blosc:snappy',
'blosc:zlib', 'blosc:zstd'}.
Specifying a compression library which is not available issues
a ValueError.
append : bool, default False
For Table formats, append the input data to the existing.
format : {'fixed', 'table', None}, default 'fixed'
Possible values:
- 'fixed': Fixed format. Fast writing/reading. Not-appendable,
nor searchable.
- 'table': Table format. Write as a PyTables Table structure
which may perform worse but allow more flexible operations
like searching / selecting subsets of the data.
- If None, pd.get_option('io.hdf.default_format') is checked,
followed by fallback to "fixed"
errors : str, default 'strict'
Specifies how encoding and decoding errors are to be handled.
See the errors argument for :func:`open` for a full list
of options.
encoding : str, default "UTF-8"
min_itemsize : dict or int, optional
Map column names to minimum string sizes for columns.
nan_rep : Any, optional
How to represent null values as str.
Not allowed with append=True.
data_columns : list of columns or True, optional
List of columns to create as indexed data columns for on-disk
queries, or True to use all columns. By default only the axes
of the object are indexed. See :ref:`io.hdf5-query-data-columns`.
Applicable only to format='table'.
See Also
--------
DataFrame.read_hdf : Read from HDF file.
DataFrame.to_parquet : Write a DataFrame to the binary parquet format.
DataFrame.to_sql : Write to a sql table.
DataFrame.to_feather : Write out feather-format for DataFrames.
DataFrame.to_csv : Write out to a csv file.
Examples
--------
>>> df = pd.DataFrame({'A': [1, 2, 3], 'B': [4, 5, 6]},
... index=['a', 'b', 'c'])
>>> df.to_hdf('data.h5', key='df', mode='w')
We can add another object to the same file:
>>> s = pd.Series([1, 2, 3, 4])
>>> s.to_hdf('data.h5', key='s')
Reading from HDF file:
>>> pd.read_hdf('data.h5', 'df')
A B
a 1 4
b 2 5
c 3 6
>>> pd.read_hdf('data.h5', 's')
0 1
1 2
2 3
3 4
dtype: int64
Deleting file with data:
>>> import os
>>> os.remove('data.h5')
"""
from pandas.io import pytables
pytables.to_hdf(
path_or_buf,
key,
self,
mode=mode,
complevel=complevel,
complib=complib,
append=append,
format=format,
index=index,
min_itemsize=min_itemsize,
nan_rep=nan_rep,
dropna=dropna,
data_columns=data_columns,
errors=errors,
encoding=encoding,
)
def to_sql(
self,
name: str,
con,
schema=None,
if_exists: str = "fail",
index: bool_t = True,
index_label=None,
chunksize=None,
dtype=None,
method=None,
) -> None:
"""
Write records stored in a DataFrame to a SQL database.
Databases supported by SQLAlchemy [1]_ are supported. Tables can be
newly created, appended to, or overwritten.
Parameters
----------
name : str
Name of SQL table.
con : sqlalchemy.engine.Engine or sqlite3.Connection
Using SQLAlchemy makes it possible to use any DB supported by that
library. Legacy support is provided for sqlite3.Connection objects. The user
is responsible for engine disposal and connection closure for the SQLAlchemy
connectable See `here \
<https://docs.sqlalchemy.org/en/13/core/connections.html>`_.
schema : str, optional
Specify the schema (if database flavor supports this). If None, use
default schema.
if_exists : {'fail', 'replace', 'append'}, default 'fail'
How to behave if the table already exists.
* fail: Raise a ValueError.
* replace: Drop the table before inserting new values.
* append: Insert new values to the existing table.
index : bool, default True
Write DataFrame index as a column. Uses `index_label` as the column
name in the table.
index_label : str or sequence, default None
Column label for index column(s). If None is given (default) and
`index` is True, then the index names are used.
A sequence should be given if the DataFrame uses MultiIndex.
chunksize : int, optional
Specify the number of rows in each batch to be written at a time.
By default, all rows will be written at once.
dtype : dict or scalar, optional
Specifying the datatype for columns. If a dictionary is used, the
keys should be the column names and the values should be the
SQLAlchemy types or strings for the sqlite3 legacy mode. If a
scalar is provided, it will be applied to all columns.
method : {None, 'multi', callable}, optional
Controls the SQL insertion clause used:
* None : Uses standard SQL ``INSERT`` clause (one per row).
* 'multi': Pass multiple values in a single ``INSERT`` clause.
* callable with signature ``(pd_table, conn, keys, data_iter)``.
Details and a sample callable implementation can be found in the
section :ref:`insert method <io.sql.method>`.
.. versionadded:: 0.24.0
Raises
------
ValueError
When the table already exists and `if_exists` is 'fail' (the
default).
See Also
--------
read_sql : Read a DataFrame from a table.
Notes
-----
Timezone aware datetime columns will be written as
``Timestamp with timezone`` type with SQLAlchemy if supported by the
database. Otherwise, the datetimes will be stored as timezone unaware
timestamps local to the original timezone.
.. versionadded:: 0.24.0
References
----------
.. [1] https://docs.sqlalchemy.org
.. [2] https://www.python.org/dev/peps/pep-0249/
Examples
--------
Create an in-memory SQLite database.
>>> from sqlalchemy import create_engine
>>> engine = create_engine('sqlite://', echo=False)
Create a table from scratch with 3 rows.
>>> df = pd.DataFrame({'name' : ['User 1', 'User 2', 'User 3']})
>>> df
name
0 User 1
1 User 2
2 User 3
>>> df.to_sql('users', con=engine)
>>> engine.execute("SELECT * FROM users").fetchall()
[(0, 'User 1'), (1, 'User 2'), (2, 'User 3')]
>>> df1 = pd.DataFrame({'name' : ['User 4', 'User 5']})
>>> df1.to_sql('users', con=engine, if_exists='append')
>>> engine.execute("SELECT * FROM users").fetchall()
[(0, 'User 1'), (1, 'User 2'), (2, 'User 3'),
(0, 'User 4'), (1, 'User 5')]
Overwrite the table with just ``df1``.
>>> df1.to_sql('users', con=engine, if_exists='replace',
... index_label='id')
>>> engine.execute("SELECT * FROM users").fetchall()
[(0, 'User 4'), (1, 'User 5')]
Specify the dtype (especially useful for integers with missing values).
Notice that while pandas is forced to store the data as floating point,
the database supports nullable integers. When fetching the data with
Python, we get back integer scalars.
>>> df = pd.DataFrame({"A": [1, None, 2]})
>>> df
A
0 1.0
1 NaN
2 2.0
>>> from sqlalchemy.types import Integer
>>> df.to_sql('integers', con=engine, index=False,
... dtype={"A": Integer()})
>>> engine.execute("SELECT * FROM integers").fetchall()
[(1,), (None,), (2,)]
"""
from pandas.io import sql
sql.to_sql(
self,
name,
con,
schema=schema,
if_exists=if_exists,
index=index,
index_label=index_label,
chunksize=chunksize,
dtype=dtype,
method=method,
)
def to_pickle(
self,
path,
compression: Optional[str] = "infer",
protocol: int = pickle.HIGHEST_PROTOCOL,
) -> None:
"""
Pickle (serialize) object to file.
Parameters
----------
path : str
File path where the pickled object will be stored.
compression : {'infer', 'gzip', 'bz2', 'zip', 'xz', None}, \
default 'infer'
A string representing the compression to use in the output file. By
default, infers from the file extension in specified path.
protocol : int
Int which indicates which protocol should be used by the pickler,
default HIGHEST_PROTOCOL (see [1]_ paragraph 12.1.2). The possible
values are 0, 1, 2, 3, 4. A negative value for the protocol
parameter is equivalent to setting its value to HIGHEST_PROTOCOL.
.. [1] https://docs.python.org/3/library/pickle.html.
.. versionadded:: 0.21.0.
See Also
--------
read_pickle : Load pickled pandas object (or any object) from file.
DataFrame.to_hdf : Write DataFrame to an HDF5 file.
DataFrame.to_sql : Write DataFrame to a SQL database.
DataFrame.to_parquet : Write a DataFrame to the binary parquet format.
Examples
--------
>>> original_df = pd.DataFrame({"foo": range(5), "bar": range(5, 10)})
>>> original_df
foo bar
0 0 5
1 1 6
2 2 7
3 3 8
4 4 9
>>> original_df.to_pickle("./dummy.pkl")
>>> unpickled_df = pd.read_pickle("./dummy.pkl")
>>> unpickled_df
foo bar
0 0 5
1 1 6
2 2 7
3 3 8
4 4 9
>>> import os
>>> os.remove("./dummy.pkl")
"""
from pandas.io.pickle import to_pickle
to_pickle(self, path, compression=compression, protocol=protocol)
def to_clipboard(
self, excel: bool_t = True, sep: Optional[str] = None, **kwargs
) -> None:
r"""
Copy object to the system clipboard.
Write a text representation of object to the system clipboard.
This can be pasted into Excel, for example.
Parameters
----------
excel : bool, default True
Produce output in a csv format for easy pasting into excel.
- True, use the provided separator for csv pasting.
- False, write a string representation of the object to the clipboard.
sep : str, default ``'\t'``
Field delimiter.
**kwargs
These parameters will be passed to DataFrame.to_csv.
See Also
--------
DataFrame.to_csv : Write a DataFrame to a comma-separated values
(csv) file.
read_clipboard : Read text from clipboard and pass to read_table.
Notes
-----
Requirements for your platform.
- Linux : `xclip`, or `xsel` (with `PyQt4` modules)
- Windows : none
- OS X : none
Examples
--------
Copy the contents of a DataFrame to the clipboard.
>>> df = pd.DataFrame([[1, 2, 3], [4, 5, 6]], columns=['A', 'B', 'C'])
>>> df.to_clipboard(sep=',')
... # Wrote the following to the system clipboard:
... # ,A,B,C
... # 0,1,2,3
... # 1,4,5,6
We can omit the index by passing the keyword `index` and setting
it to false.
>>> df.to_clipboard(sep=',', index=False)
... # Wrote the following to the system clipboard:
... # A,B,C
... # 1,2,3
... # 4,5,6
"""
from pandas.io import clipboards
clipboards.to_clipboard(self, excel=excel, sep=sep, **kwargs)
def to_xarray(self):
"""
Return an xarray object from the pandas object.
Returns
-------
xarray.DataArray or xarray.Dataset
Data in the pandas structure converted to Dataset if the object is
a DataFrame, or a DataArray if the object is a Series.
See Also
--------
DataFrame.to_hdf : Write DataFrame to an HDF5 file.
DataFrame.to_parquet : Write a DataFrame to the binary parquet format.
Notes
-----
See the `xarray docs <https://xarray.pydata.org/en/stable/>`__
Examples
--------
>>> df = pd.DataFrame([('falcon', 'bird', 389.0, 2),
... ('parrot', 'bird', 24.0, 2),
... ('lion', 'mammal', 80.5, 4),
... ('monkey', 'mammal', np.nan, 4)],
... columns=['name', 'class', 'max_speed',
... 'num_legs'])
>>> df
name class max_speed num_legs
0 falcon bird 389.0 2
1 parrot bird 24.0 2
2 lion mammal 80.5 4
3 monkey mammal NaN 4
>>> df.to_xarray()
<xarray.Dataset>
Dimensions: (index: 4)
Coordinates:
* index (index) int64 0 1 2 3
Data variables:
name (index) object 'falcon' 'parrot' 'lion' 'monkey'
class (index) object 'bird' 'bird' 'mammal' 'mammal'
max_speed (index) float64 389.0 24.0 80.5 nan
num_legs (index) int64 2 2 4 4
>>> df['max_speed'].to_xarray()
<xarray.DataArray 'max_speed' (index: 4)>
array([389. , 24. , 80.5, nan])
Coordinates:
* index (index) int64 0 1 2 3
>>> dates = pd.to_datetime(['2018-01-01', '2018-01-01',
... '2018-01-02', '2018-01-02'])
>>> df_multiindex = pd.DataFrame({'date': dates,
... 'animal': ['falcon', 'parrot',
... 'falcon', 'parrot'],
... 'speed': [350, 18, 361, 15]})
>>> df_multiindex = df_multiindex.set_index(['date', 'animal'])
>>> df_multiindex
speed
date animal
2018-01-01 falcon 350
parrot 18
2018-01-02 falcon 361
parrot 15
>>> df_multiindex.to_xarray()
<xarray.Dataset>
Dimensions: (animal: 2, date: 2)
Coordinates:
* date (date) datetime64[ns] 2018-01-01 2018-01-02
* animal (animal) object 'falcon' 'parrot'
Data variables:
speed (date, animal) int64 350 18 361 15
"""
xarray = import_optional_dependency("xarray")
if self.ndim == 1:
return xarray.DataArray.from_series(self)
else:
return xarray.Dataset.from_dataframe(self)
@Substitution(returns=fmt.return_docstring)
def to_latex(
self,
buf=None,
columns=None,
col_space=None,
header=True,
index=True,
na_rep="NaN",
formatters=None,
float_format=None,
sparsify=None,
index_names=True,
bold_rows=False,
column_format=None,
longtable=None,
escape=None,
encoding=None,
decimal=".",
multicolumn=None,
multicolumn_format=None,
multirow=None,
caption=None,
label=None,
):
r"""
Render object to a LaTeX tabular, longtable, or nested table/tabular.
Requires ``\usepackage{booktabs}``. The output can be copy/pasted
into a main LaTeX document or read from an external file
with ``\input{table.tex}``.
.. versionchanged:: 0.20.2
Added to Series.
.. versionchanged:: 1.0.0
Added caption and label arguments.
Parameters
----------
buf : str, Path or StringIO-like, optional, default None
Buffer to write to. If None, the output is returned as a string.
columns : list of label, optional
The subset of columns to write. Writes all columns by default.
col_space : int, optional
The minimum width of each column.
header : bool or list of str, default True
Write out the column names. If a list of strings is given,
it is assumed to be aliases for the column names.
index : bool, default True
Write row names (index).
na_rep : str, default 'NaN'
Missing data representation.
formatters : list of functions or dict of {str: function}, optional
Formatter functions to apply to columns' elements by position or
name. The result of each function must be a unicode string.
List must be of length equal to the number of columns.
float_format : one-parameter function or str, optional, default None
Formatter for floating point numbers. For example
``float_format="%%.2f"`` and ``float_format="{:0.2f}".format`` will
both result in 0.1234 being formatted as 0.12.
sparsify : bool, optional
Set to False for a DataFrame with a hierarchical index to print
every multiindex key at each row. By default, the value will be
read from the config module.
index_names : bool, default True
Prints the names of the indexes.
bold_rows : bool, default False
Make the row labels bold in the output.
column_format : str, optional
The columns format as specified in `LaTeX table format
<https://en.wikibooks.org/wiki/LaTeX/Tables>`__ e.g. 'rcl' for 3
columns. By default, 'l' will be used for all columns except
columns of numbers, which default to 'r'.
longtable : bool, optional
By default, the value will be read from the pandas config
module. Use a longtable environment instead of tabular. Requires
adding a \usepackage{longtable} to your LaTeX preamble.
escape : bool, optional
By default, the value will be read from the pandas config
module. When set to False prevents from escaping latex special
characters in column names.
encoding : str, optional
A string representing the encoding to use in the output file,
defaults to 'utf-8'.
decimal : str, default '.'
Character recognized as decimal separator, e.g. ',' in Europe.
multicolumn : bool, default True
Use \multicolumn to enhance MultiIndex columns.
The default will be read from the config module.
multicolumn_format : str, default 'l'
The alignment for multicolumns, similar to `column_format`
The default will be read from the config module.
multirow : bool, default False
Use \multirow to enhance MultiIndex rows. Requires adding a
\usepackage{multirow} to your LaTeX preamble. Will print
centered labels (instead of top-aligned) across the contained
rows, separating groups via clines. The default will be read
from the pandas config module.
caption : str, optional
The LaTeX caption to be placed inside ``\caption{}`` in the output.
.. versionadded:: 1.0.0
label : str, optional
The LaTeX label to be placed inside ``\label{}`` in the output.
This is used with ``\ref{}`` in the main ``.tex`` file.
.. versionadded:: 1.0.0
%(returns)s
See Also
--------
DataFrame.to_string : Render a DataFrame to a console-friendly
tabular output.
DataFrame.to_html : Render a DataFrame as an HTML table.
Examples
--------
>>> df = pd.DataFrame({'name': ['Raphael', 'Donatello'],
... 'mask': ['red', 'purple'],
... 'weapon': ['sai', 'bo staff']})
>>> print(df.to_latex(index=False)) # doctest: +NORMALIZE_WHITESPACE
\begin{tabular}{lll}
\toprule
name & mask & weapon \\
\midrule
Raphael & red & sai \\
Donatello & purple & bo staff \\
\bottomrule
\end{tabular}
"""
# Get defaults from the pandas config
if self.ndim == 1:
self = self.to_frame()
if longtable is None:
longtable = config.get_option("display.latex.longtable")
if escape is None:
escape = config.get_option("display.latex.escape")
if multicolumn is None:
multicolumn = config.get_option("display.latex.multicolumn")
if multicolumn_format is None:
multicolumn_format = config.get_option("display.latex.multicolumn_format")
if multirow is None:
multirow = config.get_option("display.latex.multirow")
formatter = DataFrameFormatter(
self,
columns=columns,
col_space=col_space,
na_rep=na_rep,
header=header,
index=index,
formatters=formatters,
float_format=float_format,
bold_rows=bold_rows,
sparsify=sparsify,
index_names=index_names,
escape=escape,
decimal=decimal,
)
return formatter.to_latex(
buf=buf,
column_format=column_format,
longtable=longtable,
encoding=encoding,
multicolumn=multicolumn,
multicolumn_format=multicolumn_format,
multirow=multirow,
caption=caption,
label=label,
)
def to_csv(
self,
path_or_buf: Optional[FilePathOrBuffer] = None,
sep: str = ",",
na_rep: str = "",
float_format: Optional[str] = None,
columns: Optional[Sequence[Label]] = None,
header: Union[bool_t, List[str]] = True,
index: bool_t = True,
index_label: Optional[Union[bool_t, str, Sequence[Label]]] = None,
mode: str = "w",
encoding: Optional[str] = None,
compression: Optional[Union[str, Mapping[str, str]]] = "infer",
quoting: Optional[int] = None,
quotechar: str = '"',
line_terminator: Optional[str] = None,
chunksize: Optional[int] = None,
date_format: Optional[str] = None,
doublequote: bool_t = True,
escapechar: Optional[str] = None,
decimal: Optional[str] = ".",
) -> Optional[str]:
r"""
Write object to a comma-separated values (csv) file.
.. versionchanged:: 0.24.0
The order of arguments for Series was changed.
Parameters
----------
path_or_buf : str or file handle, default None
File path or object, if None is provided the result is returned as
a string. If a file object is passed it should be opened with
`newline=''`, disabling universal newlines.
.. versionchanged:: 0.24.0
Was previously named "path" for Series.
sep : str, default ','
String of length 1. Field delimiter for the output file.
na_rep : str, default ''
Missing data representation.
float_format : str, default None
Format string for floating point numbers.
columns : sequence, optional
Columns to write.
header : bool or list of str, default True
Write out the column names. If a list of strings is given it is
assumed to be aliases for the column names.
.. versionchanged:: 0.24.0
Previously defaulted to False for Series.
index : bool, default True
Write row names (index).
index_label : str or sequence, or False, default None
Column label for index column(s) if desired. If None is given, and
`header` and `index` are True, then the index names are used. A
sequence should be given if the object uses MultiIndex. If
False do not print fields for index names. Use index_label=False
for easier importing in R.
mode : str
Python write mode, default 'w'.
encoding : str, optional
A string representing the encoding to use in the output file,
defaults to 'utf-8'.
compression : str or dict, default 'infer'
If str, represents compression mode. If dict, value at 'method' is
the compression mode. Compression mode may be any of the following
possible values: {'infer', 'gzip', 'bz2', 'zip', 'xz', None}. If
compression mode is 'infer' and `path_or_buf` is path-like, then
detect compression mode from the following extensions: '.gz',
'.bz2', '.zip' or '.xz'. (otherwise no compression). If dict given
and mode is 'zip' or inferred as 'zip', other entries passed as
additional compression options.
.. versionchanged:: 1.0.0
May now be a dict with key 'method' as compression mode
and other entries as additional compression options if
compression mode is 'zip'.
quoting : optional constant from csv module
Defaults to csv.QUOTE_MINIMAL. If you have set a `float_format`
then floats are converted to strings and thus csv.QUOTE_NONNUMERIC
will treat them as non-numeric.
quotechar : str, default '\"'
String of length 1. Character used to quote fields.
line_terminator : str, optional
The newline character or character sequence to use in the output
file. Defaults to `os.linesep`, which depends on the OS in which
this method is called ('\n' for linux, '\r\n' for Windows, i.e.).
.. versionchanged:: 0.24.0
chunksize : int or None
Rows to write at a time.
date_format : str, default None
Format string for datetime objects.
doublequote : bool, default True
Control quoting of `quotechar` inside a field.
escapechar : str, default None
String of length 1. Character used to escape `sep` and `quotechar`
when appropriate.
decimal : str, default '.'
Character recognized as decimal separator. E.g. use ',' for
European data.
Returns
-------
None or str
If path_or_buf is None, returns the resulting csv format as a
string. Otherwise returns None.
See Also
--------
read_csv : Load a CSV file into a DataFrame.
to_excel : Write DataFrame to an Excel file.
Examples
--------
>>> df = pd.DataFrame({'name': ['Raphael', 'Donatello'],
... 'mask': ['red', 'purple'],
... 'weapon': ['sai', 'bo staff']})
>>> df.to_csv(index=False)
'name,mask,weapon\nRaphael,red,sai\nDonatello,purple,bo staff\n'
Create 'out.zip' containing 'out.csv'
>>> compression_opts = dict(method='zip',
... archive_name='out.csv') # doctest: +SKIP
>>> df.to_csv('out.zip', index=False,
... compression=compression_opts) # doctest: +SKIP
"""
df = self if isinstance(self, ABCDataFrame) else self.to_frame()
from pandas.io.formats.csvs import CSVFormatter
formatter = CSVFormatter(
df,
path_or_buf,
line_terminator=line_terminator,
sep=sep,
encoding=encoding,
compression=compression,
quoting=quoting,
na_rep=na_rep,
float_format=float_format,
cols=columns,
header=header,
index=index,
index_label=index_label,
mode=mode,
chunksize=chunksize,
quotechar=quotechar,
date_format=date_format,
doublequote=doublequote,
escapechar=escapechar,
decimal=decimal,
)
formatter.save()
if path_or_buf is None:
return formatter.path_or_buf.getvalue()
return None
# ----------------------------------------------------------------------
# Lookup Caching
def _set_as_cached(self, item, cacher) -> None:
"""
Set the _cacher attribute on the calling object with a weakref to
cacher.
"""
self._cacher = (item, weakref.ref(cacher))
def _reset_cacher(self) -> None:
"""
Reset the cacher.
"""
if hasattr(self, "_cacher"):
del self._cacher
def _maybe_cache_changed(self, item, value) -> None:
"""
The object has called back to us saying maybe it has changed.
"""
self._data.set(item, value)
@property
def _is_cached(self) -> bool_t:
"""Return boolean indicating if self is cached or not."""
return getattr(self, "_cacher", None) is not None
def _get_cacher(self):
"""return my cacher or None"""
cacher = getattr(self, "_cacher", None)
if cacher is not None:
cacher = cacher[1]()
return cacher
def _maybe_update_cacher(
self, clear: bool_t = False, verify_is_copy: bool_t = True
) -> None:
"""
See if we need to update our parent cacher if clear, then clear our
cache.
Parameters
----------
clear : bool, default False
Clear the item cache.
verify_is_copy : bool, default True
Provide is_copy checks.
"""
cacher = getattr(self, "_cacher", None)
if cacher is not None:
ref = cacher[1]()
# we are trying to reference a dead referant, hence
# a copy
if ref is None:
del self._cacher
else:
# Note: we need to call ref._maybe_cache_changed even in the
# case where it will raise. (Uh, not clear why)
try:
ref._maybe_cache_changed(cacher[0], self)
except AssertionError:
# ref._data.setitem can raise
# AssertionError because of shape mismatch
pass
if verify_is_copy:
self._check_setitem_copy(stacklevel=5, t="referant")
if clear:
self._clear_item_cache()
def _clear_item_cache(self) -> None:
self._item_cache.clear()
# ----------------------------------------------------------------------
# Indexing Methods
def take(
self: FrameOrSeries, indices, axis=0, is_copy: Optional[bool_t] = None, **kwargs
) -> FrameOrSeries:
"""
Return the elements in the given *positional* indices along an axis.
This means that we are not indexing according to actual values in
the index attribute of the object. We are indexing according to the
actual position of the element in the object.
Parameters
----------
indices : array-like
An array of ints indicating which positions to take.
axis : {0 or 'index', 1 or 'columns', None}, default 0
The axis on which to select elements. ``0`` means that we are
selecting rows, ``1`` means that we are selecting columns.
is_copy : bool
Before pandas 1.0, ``is_copy=False`` can be specified to ensure
that the return value is an actual copy. Starting with pandas 1.0,
``take`` always returns a copy, and the keyword is therefore
deprecated.
.. deprecated:: 1.0.0
**kwargs
For compatibility with :meth:`numpy.take`. Has no effect on the
output.
Returns
-------
taken : same type as caller
An array-like containing the elements taken from the object.
See Also
--------
DataFrame.loc : Select a subset of a DataFrame by labels.
DataFrame.iloc : Select a subset of a DataFrame by positions.
numpy.take : Take elements from an array along an axis.
Examples
--------
>>> df = pd.DataFrame([('falcon', 'bird', 389.0),
... ('parrot', 'bird', 24.0),
... ('lion', 'mammal', 80.5),
... ('monkey', 'mammal', np.nan)],
... columns=['name', 'class', 'max_speed'],
... index=[0, 2, 3, 1])
>>> df
name class max_speed
0 falcon bird 389.0
2 parrot bird 24.0
3 lion mammal 80.5
1 monkey mammal NaN
Take elements at positions 0 and 3 along the axis 0 (default).
Note how the actual indices selected (0 and 1) do not correspond to
our selected indices 0 and 3. That's because we are selecting the 0th
and 3rd rows, not rows whose indices equal 0 and 3.
>>> df.take([0, 3])
name class max_speed
0 falcon bird 389.0
1 monkey mammal NaN
Take elements at indices 1 and 2 along the axis 1 (column selection).
>>> df.take([1, 2], axis=1)
class max_speed
0 bird 389.0
2 bird 24.0
3 mammal 80.5
1 mammal NaN
We may take elements using negative integers for positive indices,
starting from the end of the object, just like with Python lists.
>>> df.take([-1, -2])
name class max_speed
1 monkey mammal NaN
3 lion mammal 80.5
"""
if is_copy is not None:
warnings.warn(
"is_copy is deprecated and will be removed in a future version. "
"'take' always returns a copy, so there is no need to specify this.",
FutureWarning,
stacklevel=2,
)
nv.validate_take(tuple(), kwargs)
self._consolidate_inplace()
new_data = self._data.take(
indices, axis=self._get_block_manager_axis(axis), verify=True
)
return self._constructor(new_data).__finalize__(self)
def _take_with_is_copy(
self: FrameOrSeries, indices, axis=0, **kwargs
) -> FrameOrSeries:
"""
Internal version of the `take` method that sets the `_is_copy`
attribute to keep track of the parent dataframe (using in indexing
for the SettingWithCopyWarning).
See the docstring of `take` for full explanation of the parameters.
"""
result = self.take(indices=indices, axis=axis, **kwargs)
# Maybe set copy if we didn't actually change the index.
if not result._get_axis(axis).equals(self._get_axis(axis)):
result._set_is_copy(self)
return result
def xs(self, key, axis=0, level=None, drop_level: bool_t = True):
"""
Return cross-section from the Series/DataFrame.
This method takes a `key` argument to select data at a particular
level of a MultiIndex.
Parameters
----------
key : label or tuple of label
Label contained in the index, or partially in a MultiIndex.
axis : {0 or 'index', 1 or 'columns'}, default 0
Axis to retrieve cross-section on.
level : object, defaults to first n levels (n=1 or len(key))
In case of a key partially contained in a MultiIndex, indicate
which levels are used. Levels can be referred by label or position.
drop_level : bool, default True
If False, returns object with same levels as self.
Returns
-------
Series or DataFrame
Cross-section from the original Series or DataFrame
corresponding to the selected index levels.
See Also
--------
DataFrame.loc : Access a group of rows and columns
by label(s) or a boolean array.
DataFrame.iloc : Purely integer-location based indexing
for selection by position.
Notes
-----
`xs` can not be used to set values.
MultiIndex Slicers is a generic way to get/set values on
any level or levels.
It is a superset of `xs` functionality, see
:ref:`MultiIndex Slicers <advanced.mi_slicers>`.
Examples
--------
>>> d = {'num_legs': [4, 4, 2, 2],
... 'num_wings': [0, 0, 2, 2],
... 'class': ['mammal', 'mammal', 'mammal', 'bird'],
... 'animal': ['cat', 'dog', 'bat', 'penguin'],
... 'locomotion': ['walks', 'walks', 'flies', 'walks']}
>>> df = pd.DataFrame(data=d)
>>> df = df.set_index(['class', 'animal', 'locomotion'])
>>> df
num_legs num_wings
class animal locomotion
mammal cat walks 4 0
dog walks 4 0
bat flies 2 2
bird penguin walks 2 2
Get values at specified index
>>> df.xs('mammal')
num_legs num_wings
animal locomotion
cat walks 4 0
dog walks 4 0
bat flies 2 2
Get values at several indexes
>>> df.xs(('mammal', 'dog'))
num_legs num_wings
locomotion
walks 4 0
Get values at specified index and level
>>> df.xs('cat', level=1)
num_legs num_wings
class locomotion
mammal walks 4 0
Get values at several indexes and levels
>>> df.xs(('bird', 'walks'),
... level=[0, 'locomotion'])
num_legs num_wings
animal
penguin 2 2
Get values at specified column and axis
>>> df.xs('num_wings', axis=1)
class animal locomotion
mammal cat walks 0
dog walks 0
bat flies 2
bird penguin walks 2
Name: num_wings, dtype: int64
"""
axis = self._get_axis_number(axis)
labels = self._get_axis(axis)
if level is not None:
loc, new_ax = labels.get_loc_level(key, level=level, drop_level=drop_level)
# create the tuple of the indexer
_indexer = [slice(None)] * self.ndim
_indexer[axis] = loc
indexer = tuple(_indexer)
result = self.iloc[indexer]
setattr(result, result._get_axis_name(axis), new_ax)
return result
if axis == 1:
return self[key]
self._consolidate_inplace()
index = self.index
if isinstance(index, MultiIndex):
loc, new_index = self.index.get_loc_level(key, drop_level=drop_level)
else:
loc = self.index.get_loc(key)
if isinstance(loc, np.ndarray):
if loc.dtype == np.bool_:
(inds,) = loc.nonzero()
return self._take_with_is_copy(inds, axis=axis)
else:
return self._take_with_is_copy(loc, axis=axis)
if not is_scalar(loc):
new_index = self.index[loc]
if is_scalar(loc):
# In this case loc should be an integer
if self.ndim == 1:
# if we encounter an array-like and we only have 1 dim
# that means that their are list/ndarrays inside the Series!
# so just return them (GH 6394)
return self._values[loc]
new_values = self._data.fast_xs(loc)
result = self._constructor_sliced(
new_values,
index=self.columns,
name=self.index[loc],
dtype=new_values.dtype,
)
else:
result = self.iloc[loc]
result.index = new_index
# this could be a view
# but only in a single-dtyped view sliceable case
result._set_is_copy(self, copy=not result._is_view)
return result
_xs: Callable = xs
def __getitem__(self, item):
raise AbstractMethodError(self)
def _get_item_cache(self, item):
"""Return the cached item, item represents a label indexer."""
cache = self._item_cache
res = cache.get(item)
if res is None:
values = self._data.get(item)
res = self._box_item_values(item, values)
cache[item] = res
res._set_as_cached(item, self)
# for a chain
res._is_copy = self._is_copy
return res
def _iget_item_cache(self, item: int):
"""Return the cached item, item represents a positional indexer."""
ax = self._info_axis
if ax.is_unique:
lower = self._get_item_cache(ax[item])
else:
return self._ixs(item, axis=1)
return lower
def _box_item_values(self, key, values):
raise AbstractMethodError(self)
def _slice(self: FrameOrSeries, slobj: slice, axis=0) -> FrameOrSeries:
"""
Construct a slice of this container.
Slicing with this method is *always* positional.
"""
assert isinstance(slobj, slice), type(slobj)
axis = self._get_block_manager_axis(axis)
result = self._constructor(self._data.get_slice(slobj, axis=axis))
result = result.__finalize__(self)
# this could be a view
# but only in a single-dtyped view sliceable case
is_copy = axis != 0 or result._is_view
result._set_is_copy(self, copy=is_copy)
return result
def _set_item(self, key, value) -> None:
self._data.set(key, value)
self._clear_item_cache()
def _set_is_copy(self, ref, copy: bool_t = True) -> None:
if not copy:
self._is_copy = None
else:
assert ref is not None
self._is_copy = weakref.ref(ref)
def _check_is_chained_assignment_possible(self) -> bool_t:
"""
Check if we are a view, have a cacher, and are of mixed type.
If so, then force a setitem_copy check.
Should be called just near setting a value
Will return a boolean if it we are a view and are cached, but a
single-dtype meaning that the cacher should be updated following
setting.
"""
if self._is_view and self._is_cached:
ref = self._get_cacher()
if ref is not None and ref._is_mixed_type:
self._check_setitem_copy(stacklevel=4, t="referant", force=True)
return True
elif self._is_copy:
self._check_setitem_copy(stacklevel=4, t="referant")
return False
def _check_setitem_copy(self, stacklevel=4, t="setting", force=False):
"""
Parameters
----------
stacklevel : int, default 4
the level to show of the stack when the error is output
t : str, the type of setting error
force : bool, default False
If True, then force showing an error.
validate if we are doing a setitem on a chained copy.
If you call this function, be sure to set the stacklevel such that the
user will see the error *at the level of setting*
It is technically possible to figure out that we are setting on
a copy even WITH a multi-dtyped pandas object. In other words, some
blocks may be views while other are not. Currently _is_view will ALWAYS
return False for multi-blocks to avoid having to handle this case.
df = DataFrame(np.arange(0,9), columns=['count'])
df['group'] = 'b'
# This technically need not raise SettingWithCopy if both are view
# (which is not # generally guaranteed but is usually True. However,
# this is in general not a good practice and we recommend using .loc.
df.iloc[0:5]['group'] = 'a'
"""
# return early if the check is not needed
if not (force or self._is_copy):
return
value = config.get_option("mode.chained_assignment")
if value is None:
return
# see if the copy is not actually referred; if so, then dissolve
# the copy weakref
if self._is_copy is not None and not isinstance(self._is_copy, str):
r = self._is_copy()
if not gc.get_referents(r) or r.shape == self.shape:
self._is_copy = None
return
# a custom message
if isinstance(self._is_copy, str):
t = self._is_copy
elif t == "referant":
t = (
"\n"
"A value is trying to be set on a copy of a slice from a "
"DataFrame\n\n"
"See the caveats in the documentation: "
"https://pandas.pydata.org/pandas-docs/stable/user_guide/"
"indexing.html#returning-a-view-versus-a-copy"
)
else:
t = (
"\n"
"A value is trying to be set on a copy of a slice from a "
"DataFrame.\n"
"Try using .loc[row_indexer,col_indexer] = value "
"instead\n\nSee the caveats in the documentation: "
"https://pandas.pydata.org/pandas-docs/stable/user_guide/"
"indexing.html#returning-a-view-versus-a-copy"
)
if value == "raise":
raise com.SettingWithCopyError(t)
elif value == "warn":
warnings.warn(t, com.SettingWithCopyWarning, stacklevel=stacklevel)
def __delitem__(self, key) -> None:
"""
Delete item
"""
deleted = False
maybe_shortcut = False
if self.ndim == 2 and isinstance(self.columns, MultiIndex):
try:
maybe_shortcut = key not in self.columns._engine
except TypeError:
pass
if maybe_shortcut:
# Allow shorthand to delete all columns whose first len(key)
# elements match key:
if not isinstance(key, tuple):
key = (key,)
for col in self.columns:
if isinstance(col, tuple) and col[: len(key)] == key:
del self[col]
deleted = True
if not deleted:
# If the above loop ran and didn't delete anything because
# there was no match, this call should raise the appropriate
# exception:
self._data.delete(key)
# delete from the caches
try:
del self._item_cache[key]
except KeyError:
pass
# ----------------------------------------------------------------------
# Unsorted
def get(self, key, default=None):
"""
Get item from object for given key (ex: DataFrame column).
Returns default value if not found.
Parameters
----------
key : object
Returns
-------
value : same type as items contained in object
"""
try:
return self[key]
except (KeyError, ValueError, IndexError):
return default
@property
def _is_view(self):
"""Return boolean indicating if self is view of another array """
return self._data.is_view
def reindex_like(
self: FrameOrSeries,
other,
method: Optional[str] = None,
copy: bool_t = True,
limit=None,
tolerance=None,
) -> FrameOrSeries:
"""
Return an object with matching indices as other object.
Conform the object to the same index on all axes. Optional
filling logic, placing NaN in locations having no value
in the previous index. A new object is produced unless the
new index is equivalent to the current one and copy=False.
Parameters
----------
other : Object of the same data type
Its row and column indices are used to define the new indices
of this object.
method : {None, 'backfill'/'bfill', 'pad'/'ffill', 'nearest'}
Method to use for filling holes in reindexed DataFrame.
Please note: this is only applicable to DataFrames/Series with a
monotonically increasing/decreasing index.
* None (default): don't fill gaps
* pad / ffill: propagate last valid observation forward to next
valid
* backfill / bfill: use next valid observation to fill gap
* nearest: use nearest valid observations to fill gap.
copy : bool, default True
Return a new object, even if the passed indexes are the same.
limit : int, default None
Maximum number of consecutive labels to fill for inexact matches.
tolerance : optional
Maximum distance between original and new labels for inexact
matches. The values of the index at the matching locations most
satisfy the equation ``abs(index[indexer] - target) <= tolerance``.
Tolerance may be a scalar value, which applies the same tolerance
to all values, or list-like, which applies variable tolerance per
element. List-like includes list, tuple, array, Series, and must be
the same size as the index and its dtype must exactly match the
index's type.
.. versionadded:: 0.21.0 (list-like tolerance)
Returns
-------
Series or DataFrame
Same type as caller, but with changed indices on each axis.
See Also
--------
DataFrame.set_index : Set row labels.
DataFrame.reset_index : Remove row labels or move them to new columns.
DataFrame.reindex : Change to new indices or expand indices.
Notes
-----
Same as calling
``.reindex(index=other.index, columns=other.columns,...)``.
Examples
--------
>>> df1 = pd.DataFrame([[24.3, 75.7, 'high'],
... [31, 87.8, 'high'],
... [22, 71.6, 'medium'],
... [35, 95, 'medium']],
... columns=['temp_celsius', 'temp_fahrenheit',
... 'windspeed'],
... index=pd.date_range(start='2014-02-12',
... end='2014-02-15', freq='D'))
>>> df1
temp_celsius temp_fahrenheit windspeed
2014-02-12 24.3 75.7 high
2014-02-13 31.0 87.8 high
2014-02-14 22.0 71.6 medium
2014-02-15 35.0 95.0 medium
>>> df2 = pd.DataFrame([[28, 'low'],
... [30, 'low'],
... [35.1, 'medium']],
... columns=['temp_celsius', 'windspeed'],
... index=pd.DatetimeIndex(['2014-02-12', '2014-02-13',
... '2014-02-15']))
>>> df2
temp_celsius windspeed
2014-02-12 28.0 low
2014-02-13 30.0 low
2014-02-15 35.1 medium
>>> df2.reindex_like(df1)
temp_celsius temp_fahrenheit windspeed
2014-02-12 28.0 NaN low
2014-02-13 30.0 NaN low
2014-02-14 NaN NaN NaN
2014-02-15 35.1 NaN medium
"""
d = other._construct_axes_dict(
axes=self._AXIS_ORDERS,
method=method,
copy=copy,
limit=limit,
tolerance=tolerance,
)
return self.reindex(**d)
def drop(
self,
labels=None,
axis=0,
index=None,
columns=None,
level=None,
inplace: bool_t = False,
errors: str = "raise",
):
inplace = validate_bool_kwarg(inplace, "inplace")
if labels is not None:
if index is not None or columns is not None:
raise ValueError("Cannot specify both 'labels' and 'index'/'columns'")
axis_name = self._get_axis_name(axis)
axes = {axis_name: labels}
elif index is not None or columns is not None:
axes, _ = self._construct_axes_from_arguments((index, columns), {})
else:
raise ValueError(
"Need to specify at least one of 'labels', 'index' or 'columns'"
)
obj = self
for axis, labels in axes.items():
if labels is not None:
obj = obj._drop_axis(labels, axis, level=level, errors=errors)
if inplace:
self._update_inplace(obj)
else:
return obj
def _drop_axis(
self: FrameOrSeries, labels, axis, level=None, errors: str = "raise"
) -> FrameOrSeries:
"""
Drop labels from specified axis. Used in the ``drop`` method
internally.
Parameters
----------
labels : single label or list-like
axis : int or axis name
level : int or level name, default None
For MultiIndex
errors : {'ignore', 'raise'}, default 'raise'
If 'ignore', suppress error and existing labels are dropped.
"""
axis = self._get_axis_number(axis)
axis_name = self._get_axis_name(axis)
axis = self._get_axis(axis)
if axis.is_unique:
if level is not None:
if not isinstance(axis, MultiIndex):
raise AssertionError("axis must be a MultiIndex")
new_axis = axis.drop(labels, level=level, errors=errors)
else:
new_axis = axis.drop(labels, errors=errors)
result = self.reindex(**{axis_name: new_axis})
# Case for non-unique axis
else:
labels = ensure_object(com.index_labels_to_array(labels))
if level is not None:
if not isinstance(axis, MultiIndex):
raise AssertionError("axis must be a MultiIndex")
indexer = ~axis.get_level_values(level).isin(labels)
# GH 18561 MultiIndex.drop should raise if label is absent
if errors == "raise" and indexer.all():
raise KeyError(f"{labels} not found in axis")
else:
indexer = ~axis.isin(labels)
# Check if label doesn't exist along axis
labels_missing = (axis.get_indexer_for(labels) == -1).any()
if errors == "raise" and labels_missing:
raise KeyError(f"{labels} not found in axis")
slicer = [slice(None)] * self.ndim
slicer[self._get_axis_number(axis_name)] = indexer
result = self.loc[tuple(slicer)]
return result
def _update_inplace(self, result, verify_is_copy: bool_t = True) -> None:
"""
Replace self internals with result.
Parameters
----------
verify_is_copy : bool, default True
Provide is_copy checks.
"""
# NOTE: This does *not* call __finalize__ and that's an explicit
# decision that we may revisit in the future.
self._reset_cache()
self._clear_item_cache()
self._data = getattr(result, "_data", result)
self._maybe_update_cacher(verify_is_copy=verify_is_copy)
def add_prefix(self: FrameOrSeries, prefix: str) -> FrameOrSeries:
"""
Prefix labels with string `prefix`.
For Series, the row labels are prefixed.
For DataFrame, the column labels are prefixed.
Parameters
----------
prefix : str
The string to add before each label.
Returns
-------
Series or DataFrame
New Series or DataFrame with updated labels.
See Also
--------
Series.add_suffix: Suffix row labels with string `suffix`.
DataFrame.add_suffix: Suffix column labels with string `suffix`.
Examples
--------
>>> s = pd.Series([1, 2, 3, 4])
>>> s
0 1
1 2
2 3
3 4
dtype: int64
>>> s.add_prefix('item_')
item_0 1
item_1 2
item_2 3
item_3 4
dtype: int64
>>> df = pd.DataFrame({'A': [1, 2, 3, 4], 'B': [3, 4, 5, 6]})
>>> df
A B
0 1 3
1 2 4
2 3 5
3 4 6
>>> df.add_prefix('col_')
col_A col_B
0 1 3
1 2 4
2 3 5
3 4 6
"""
f = functools.partial("{prefix}{}".format, prefix=prefix)
mapper = {self._info_axis_name: f}
return self.rename(**mapper) # type: ignore
def add_suffix(self: FrameOrSeries, suffix: str) -> FrameOrSeries:
"""
Suffix labels with string `suffix`.
For Series, the row labels are suffixed.
For DataFrame, the column labels are suffixed.
Parameters
----------
suffix : str
The string to add after each label.
Returns
-------
Series or DataFrame
New Series or DataFrame with updated labels.
See Also
--------
Series.add_prefix: Prefix row labels with string `prefix`.
DataFrame.add_prefix: Prefix column labels with string `prefix`.
Examples
--------
>>> s = pd.Series([1, 2, 3, 4])
>>> s
0 1
1 2
2 3
3 4
dtype: int64
>>> s.add_suffix('_item')
0_item 1
1_item 2
2_item 3
3_item 4
dtype: int64
>>> df = pd.DataFrame({'A': [1, 2, 3, 4], 'B': [3, 4, 5, 6]})
>>> df
A B
0 1 3
1 2 4
2 3 5
3 4 6
>>> df.add_suffix('_col')
A_col B_col
0 1 3
1 2 4
2 3 5
3 4 6
"""
f = functools.partial("{}{suffix}".format, suffix=suffix)
mapper = {self._info_axis_name: f}
return self.rename(**mapper) # type: ignore
def sort_values(
self,
axis=0,
ascending=True,
inplace: bool_t = False,
kind: str = "quicksort",
na_position: str = "last",
ignore_index: bool_t = False,
):
"""
Sort by the values along either axis.
Parameters
----------%(optional_by)s
axis : %(axes_single_arg)s, default 0
Axis to be sorted.
ascending : bool or list of bool, default True
Sort ascending vs. descending. Specify list for multiple sort
orders. If this is a list of bools, must match the length of
the by.
inplace : bool, default False
If True, perform operation in-place.
kind : {'quicksort', 'mergesort', 'heapsort'}, default 'quicksort'
Choice of sorting algorithm. See also ndarray.np.sort for more
information. `mergesort` is the only stable algorithm. For
DataFrames, this option is only applied when sorting on a single
column or label.
na_position : {'first', 'last'}, default 'last'
Puts NaNs at the beginning if `first`; `last` puts NaNs at the
end.
ignore_index : bool, default False
If True, the resulting axis will be labeled 0, 1, …, n - 1.
.. versionadded:: 1.0.0
Returns
-------
sorted_obj : DataFrame or None
DataFrame with sorted values if inplace=False, None otherwise.
Examples
--------
>>> df = pd.DataFrame({
... 'col1': ['A', 'A', 'B', np.nan, 'D', 'C'],
... 'col2': [2, 1, 9, 8, 7, 4],
... 'col3': [0, 1, 9, 4, 2, 3],
... })
>>> df
col1 col2 col3
0 A 2 0
1 A 1 1
2 B 9 9
3 NaN 8 4
4 D 7 2
5 C 4 3
Sort by col1
>>> df.sort_values(by=['col1'])
col1 col2 col3
0 A 2 0
1 A 1 1
2 B 9 9
5 C 4 3
4 D 7 2
3 NaN 8 4
Sort by multiple columns
>>> df.sort_values(by=['col1', 'col2'])
col1 col2 col3
1 A 1 1
0 A 2 0
2 B 9 9
5 C 4 3
4 D 7 2
3 NaN 8 4
Sort Descending
>>> df.sort_values(by='col1', ascending=False)
col1 col2 col3
4 D 7 2
5 C 4 3
2 B 9 9
0 A 2 0
1 A 1 1
3 NaN 8 4
Putting NAs first
>>> df.sort_values(by='col1', ascending=False, na_position='first')
col1 col2 col3
3 NaN 8 4
4 D 7 2
5 C 4 3
2 B 9 9
0 A 2 0
1 A 1 1
"""
raise AbstractMethodError(self)
def reindex(self: FrameOrSeries, *args, **kwargs) -> FrameOrSeries:
"""
Conform %(klass)s to new index with optional filling logic.
Places NA/NaN in locations having no value in the previous index. A new object
is produced unless the new index is equivalent to the current one and
``copy=False``.
Parameters
----------
%(optional_labels)s
%(axes)s : array-like, optional
New labels / index to conform to, should be specified using
keywords. Preferably an Index object to avoid duplicating data.
%(optional_axis)s
method : {None, 'backfill'/'bfill', 'pad'/'ffill', 'nearest'}
Method to use for filling holes in reindexed DataFrame.
Please note: this is only applicable to DataFrames/Series with a
monotonically increasing/decreasing index.
* None (default): don't fill gaps
* pad / ffill: Propagate last valid observation forward to next
valid.
* backfill / bfill: Use next valid observation to fill gap.
* nearest: Use nearest valid observations to fill gap.
copy : bool, default True
Return a new object, even if the passed indexes are the same.
level : int or name
Broadcast across a level, matching Index values on the
passed MultiIndex level.
fill_value : scalar, default np.NaN
Value to use for missing values. Defaults to NaN, but can be any
"compatible" value.
limit : int, default None
Maximum number of consecutive elements to forward or backward fill.
tolerance : optional
Maximum distance between original and new labels for inexact
matches. The values of the index at the matching locations most
satisfy the equation ``abs(index[indexer] - target) <= tolerance``.
Tolerance may be a scalar value, which applies the same tolerance
to all values, or list-like, which applies variable tolerance per
element. List-like includes list, tuple, array, Series, and must be
the same size as the index and its dtype must exactly match the
index's type.
.. versionadded:: 0.21.0 (list-like tolerance)
Returns
-------
%(klass)s with changed index.
See Also
--------
DataFrame.set_index : Set row labels.
DataFrame.reset_index : Remove row labels or move them to new columns.
DataFrame.reindex_like : Change to same indices as other DataFrame.
Examples
--------
``DataFrame.reindex`` supports two calling conventions
* ``(index=index_labels, columns=column_labels, ...)``
* ``(labels, axis={'index', 'columns'}, ...)``
We *highly* recommend using keyword arguments to clarify your
intent.
Create a dataframe with some fictional data.
>>> index = ['Firefox', 'Chrome', 'Safari', 'IE10', 'Konqueror']
>>> df = pd.DataFrame({'http_status': [200, 200, 404, 404, 301],
... 'response_time': [0.04, 0.02, 0.07, 0.08, 1.0]},
... index=index)
>>> df
http_status response_time
Firefox 200 0.04
Chrome 200 0.02
Safari 404 0.07
IE10 404 0.08
Konqueror 301 1.00
Create a new index and reindex the dataframe. By default
values in the new index that do not have corresponding
records in the dataframe are assigned ``NaN``.
>>> new_index = ['Safari', 'Iceweasel', 'Comodo Dragon', 'IE10',
... 'Chrome']
>>> df.reindex(new_index)
http_status response_time
Safari 404.0 0.07
Iceweasel NaN NaN
Comodo Dragon NaN NaN
IE10 404.0 0.08
Chrome 200.0 0.02
We can fill in the missing values by passing a value to
the keyword ``fill_value``. Because the index is not monotonically
increasing or decreasing, we cannot use arguments to the keyword
``method`` to fill the ``NaN`` values.
>>> df.reindex(new_index, fill_value=0)
http_status response_time
Safari 404 0.07
Iceweasel 0 0.00
Comodo Dragon 0 0.00
IE10 404 0.08
Chrome 200 0.02
>>> df.reindex(new_index, fill_value='missing')
http_status response_time
Safari 404 0.07
Iceweasel missing missing
Comodo Dragon missing missing
IE10 404 0.08
Chrome 200 0.02
We can also reindex the columns.
>>> df.reindex(columns=['http_status', 'user_agent'])
http_status user_agent
Firefox 200 NaN
Chrome 200 NaN
Safari 404 NaN
IE10 404 NaN
Konqueror 301 NaN
Or we can use "axis-style" keyword arguments
>>> df.reindex(['http_status', 'user_agent'], axis="columns")
http_status user_agent
Firefox 200 NaN
Chrome 200 NaN
Safari 404 NaN
IE10 404 NaN
Konqueror 301 NaN
To further illustrate the filling functionality in
``reindex``, we will create a dataframe with a
monotonically increasing index (for example, a sequence
of dates).
>>> date_index = pd.date_range('1/1/2010', periods=6, freq='D')
>>> df2 = pd.DataFrame({"prices": [100, 101, np.nan, 100, 89, 88]},
... index=date_index)
>>> df2
prices
2010-01-01 100.0
2010-01-02 101.0
2010-01-03 NaN
2010-01-04 100.0
2010-01-05 89.0
2010-01-06 88.0
Suppose we decide to expand the dataframe to cover a wider
date range.
>>> date_index2 = pd.date_range('12/29/2009', periods=10, freq='D')
>>> df2.reindex(date_index2)
prices
2009-12-29 NaN
2009-12-30 NaN
2009-12-31 NaN
2010-01-01 100.0
2010-01-02 101.0
2010-01-03 NaN
2010-01-04 100.0
2010-01-05 89.0
2010-01-06 88.0
2010-01-07 NaN
The index entries that did not have a value in the original data frame
(for example, '2009-12-29') are by default filled with ``NaN``.
If desired, we can fill in the missing values using one of several
options.
For example, to back-propagate the last valid value to fill the ``NaN``
values, pass ``bfill`` as an argument to the ``method`` keyword.
>>> df2.reindex(date_index2, method='bfill')
prices
2009-12-29 100.0
2009-12-30 100.0
2009-12-31 100.0
2010-01-01 100.0
2010-01-02 101.0
2010-01-03 NaN
2010-01-04 100.0
2010-01-05 89.0
2010-01-06 88.0
2010-01-07 NaN
Please note that the ``NaN`` value present in the original dataframe
(at index value 2010-01-03) will not be filled by any of the
value propagation schemes. This is because filling while reindexing
does not look at dataframe values, but only compares the original and
desired indexes. If you do want to fill in the ``NaN`` values present
in the original dataframe, use the ``fillna()`` method.
See the :ref:`user guide <basics.reindexing>` for more.
"""
# TODO: Decide if we care about having different examples for different
# kinds
# construct the args
axes, kwargs = self._construct_axes_from_arguments(args, kwargs)
method = missing.clean_reindex_fill_method(kwargs.pop("method", None))
level = kwargs.pop("level", None)
copy = kwargs.pop("copy", True)
limit = kwargs.pop("limit", None)
tolerance = kwargs.pop("tolerance", None)
fill_value = kwargs.pop("fill_value", None)
# Series.reindex doesn't use / need the axis kwarg
# We pop and ignore it here, to make writing Series/Frame generic code
# easier
kwargs.pop("axis", None)
if kwargs:
raise TypeError(
"reindex() got an unexpected keyword "
f'argument "{list(kwargs.keys())[0]}"'
)
self._consolidate_inplace()
# if all axes that are requested to reindex are equal, then only copy
# if indicated must have index names equal here as well as values
if all(
self._get_axis(axis).identical(ax)
for axis, ax in axes.items()
if ax is not None
):
if copy:
return self.copy()
return self
# check if we are a multi reindex
if self._needs_reindex_multi(axes, method, level):
return self._reindex_multi(axes, copy, fill_value)
# perform the reindex on the axes
return self._reindex_axes(
axes, level, limit, tolerance, method, fill_value, copy
).__finalize__(self)
def _reindex_axes(
self: FrameOrSeries, axes, level, limit, tolerance, method, fill_value, copy
) -> FrameOrSeries:
"""Perform the reindex for all the axes."""
obj = self
for a in self._AXIS_ORDERS:
labels = axes[a]
if labels is None:
continue
ax = self._get_axis(a)
new_index, indexer = ax.reindex(
labels, level=level, limit=limit, tolerance=tolerance, method=method
)
axis = self._get_axis_number(a)
obj = obj._reindex_with_indexers(
{axis: [new_index, indexer]},
fill_value=fill_value,
copy=copy,
allow_dups=False,
)
return obj
def _needs_reindex_multi(self, axes, method, level) -> bool_t:
"""Check if we do need a multi reindex."""
return (
(com.count_not_none(*axes.values()) == self._AXIS_LEN)
and method is None
and level is None
and not self._is_mixed_type
)
def _reindex_multi(self, axes, copy, fill_value):
raise AbstractMethodError(self)
def _reindex_with_indexers(
self: FrameOrSeries,
reindexers,
fill_value=None,
copy: bool_t = False,
allow_dups: bool_t = False,
) -> FrameOrSeries:
"""allow_dups indicates an internal call here """
# reindex doing multiple operations on different axes if indicated
new_data = self._data
for axis in sorted(reindexers.keys()):
index, indexer = reindexers[axis]
baxis = self._get_block_manager_axis(axis)
if index is None:
continue
index = ensure_index(index)
if indexer is not None:
indexer = ensure_int64(indexer)
# TODO: speed up on homogeneous DataFrame objects
new_data = new_data.reindex_indexer(
index,
indexer,
axis=baxis,
fill_value=fill_value,
allow_dups=allow_dups,
copy=copy,
)
if copy and new_data is self._data:
new_data = new_data.copy()
return self._constructor(new_data).__finalize__(self)
def filter(
self: FrameOrSeries,
items=None,
like: Optional[str] = None,
regex: Optional[str] = None,
axis=None,
) -> FrameOrSeries:
"""
Subset the dataframe rows or columns according to the specified index labels.
Note that this routine does not filter a dataframe on its
contents. The filter is applied to the labels of the index.
Parameters
----------
items : list-like
Keep labels from axis which are in items.
like : str
Keep labels from axis for which "like in label == True".
regex : str (regular expression)
Keep labels from axis for which re.search(regex, label) == True.
axis : {0 or ‘index’, 1 or ‘columns’, None}, default None
The axis to filter on, expressed either as an index (int)
or axis name (str). By default this is the info axis,
'index' for Series, 'columns' for DataFrame.
Returns
-------
same type as input object
See Also
--------
DataFrame.loc
Notes
-----
The ``items``, ``like``, and ``regex`` parameters are
enforced to be mutually exclusive.
``axis`` defaults to the info axis that is used when indexing
with ``[]``.
Examples
--------
>>> df = pd.DataFrame(np.array(([1, 2, 3], [4, 5, 6])),
... index=['mouse', 'rabbit'],
... columns=['one', 'two', 'three'])
>>> # select columns by name
>>> df.filter(items=['one', 'three'])
one three
mouse 1 3
rabbit 4 6
>>> # select columns by regular expression
>>> df.filter(regex='e$', axis=1)
one three
mouse 1 3
rabbit 4 6
>>> # select rows containing 'bbi'
>>> df.filter(like='bbi', axis=0)
one two three
rabbit 4 5 6
"""
nkw = com.count_not_none(items, like, regex)
if nkw > 1:
raise TypeError(
"Keyword arguments `items`, `like`, or `regex` "
"are mutually exclusive"
)
if axis is None:
axis = self._info_axis_name
labels = self._get_axis(axis)
if items is not None:
name = self._get_axis_name(axis)
return self.reindex(**{name: [r for r in items if r in labels]})
elif like:
def f(x):
return like in ensure_str(x)
values = labels.map(f)
return self.loc(axis=axis)[values]
elif regex:
def f(x):
return matcher.search(ensure_str(x)) is not None
matcher = re.compile(regex)
values = labels.map(f)
return self.loc(axis=axis)[values]
else:
raise TypeError("Must pass either `items`, `like`, or `regex`")
def head(self: FrameOrSeries, n: int = 5) -> FrameOrSeries:
"""
Return the first `n` rows.
This function returns the first `n` rows for the object based
on position. It is useful for quickly testing if your object
has the right type of data in it.
For negative values of `n`, this function returns all rows except
the last `n` rows, equivalent to ``df[:-n]``.
Parameters
----------
n : int, default 5
Number of rows to select.
Returns
-------
same type as caller
The first `n` rows of the caller object.
See Also
--------
DataFrame.tail: Returns the last `n` rows.
Examples
--------
>>> df = pd.DataFrame({'animal': ['alligator', 'bee', 'falcon', 'lion',
... 'monkey', 'parrot', 'shark', 'whale', 'zebra']})
>>> df
animal
0 alligator
1 bee
2 falcon
3 lion
4 monkey
5 parrot
6 shark
7 whale
8 zebra
Viewing the first 5 lines
>>> df.head()
animal
0 alligator
1 bee
2 falcon
3 lion
4 monkey
Viewing the first `n` lines (three in this case)
>>> df.head(3)
animal
0 alligator
1 bee
2 falcon
For negative values of `n`
>>> df.head(-3)
animal
0 alligator
1 bee
2 falcon
3 lion
4 monkey
5 parrot
"""
return self.iloc[:n]
def tail(self: FrameOrSeries, n: int = 5) -> FrameOrSeries:
"""
Return the last `n` rows.
This function returns last `n` rows from the object based on
position. It is useful for quickly verifying data, for example,
after sorting or appending rows.
For negative values of `n`, this function returns all rows except
the first `n` rows, equivalent to ``df[n:]``.
Parameters
----------
n : int, default 5
Number of rows to select.
Returns
-------
type of caller
The last `n` rows of the caller object.
See Also
--------
DataFrame.head : The first `n` rows of the caller object.
Examples
--------
>>> df = pd.DataFrame({'animal': ['alligator', 'bee', 'falcon', 'lion',
... 'monkey', 'parrot', 'shark', 'whale', 'zebra']})
>>> df
animal
0 alligator
1 bee
2 falcon
3 lion
4 monkey
5 parrot
6 shark
7 whale
8 zebra
Viewing the last 5 lines
>>> df.tail()
animal
4 monkey
5 parrot
6 shark
7 whale
8 zebra
Viewing the last `n` lines (three in this case)
>>> df.tail(3)
animal
6 shark
7 whale
8 zebra
For negative values of `n`
>>> df.tail(-3)
animal
3 lion
4 monkey
5 parrot
6 shark
7 whale
8 zebra
"""
if n == 0:
return self.iloc[0:0]
return self.iloc[-n:]
def sample(
self: FrameOrSeries,
n=None,
frac=None,
replace=False,
weights=None,
random_state=None,
axis=None,
) -> FrameOrSeries:
"""
Return a random sample of items from an axis of object.
You can use `random_state` for reproducibility.
Parameters
----------
n : int, optional
Number of items from axis to return. Cannot be used with `frac`.
Default = 1 if `frac` = None.
frac : float, optional
Fraction of axis items to return. Cannot be used with `n`.
replace : bool, default False
Allow or disallow sampling of the same row more than once.
weights : str or ndarray-like, optional
Default 'None' results in equal probability weighting.
If passed a Series, will align with target object on index. Index
values in weights not found in sampled object will be ignored and
index values in sampled object not in weights will be assigned
weights of zero.
If called on a DataFrame, will accept the name of a column
when axis = 0.
Unless weights are a Series, weights must be same length as axis
being sampled.
If weights do not sum to 1, they will be normalized to sum to 1.
Missing values in the weights column will be treated as zero.
Infinite values not allowed.
random_state : int or numpy.random.RandomState, optional
Seed for the random number generator (if int), or numpy RandomState
object.
axis : {0 or ‘index’, 1 or ‘columns’, None}, default None
Axis to sample. Accepts axis number or name. Default is stat axis
for given data type (0 for Series and DataFrames).
Returns
-------
Series or DataFrame
A new object of same type as caller containing `n` items randomly
sampled from the caller object.
See Also
--------
numpy.random.choice: Generates a random sample from a given 1-D numpy
array.
Notes
-----
If `frac` > 1, `replacement` should be set to `True`.
Examples
--------
>>> df = pd.DataFrame({'num_legs': [2, 4, 8, 0],
... 'num_wings': [2, 0, 0, 0],
... 'num_specimen_seen': [10, 2, 1, 8]},
... index=['falcon', 'dog', 'spider', 'fish'])
>>> df
num_legs num_wings num_specimen_seen
falcon 2 2 10
dog 4 0 2
spider 8 0 1
fish 0 0 8
Extract 3 random elements from the ``Series`` ``df['num_legs']``:
Note that we use `random_state` to ensure the reproducibility of
the examples.
>>> df['num_legs'].sample(n=3, random_state=1)
fish 0
spider 8
falcon 2
Name: num_legs, dtype: int64
A random 50% sample of the ``DataFrame`` with replacement:
>>> df.sample(frac=0.5, replace=True, random_state=1)
num_legs num_wings num_specimen_seen
dog 4 0 2
fish 0 0 8
An upsample sample of the ``DataFrame`` with replacement:
Note that `replace` parameter has to be `True` for `frac` parameter > 1.
>>> df.sample(frac=2, replace=True, random_state=1)
num_legs num_wings num_specimen_seen
dog 4 0 2
fish 0 0 8
falcon 2 2 10
falcon 2 2 10
fish 0 0 8
dog 4 0 2
fish 0 0 8
dog 4 0 2
Using a DataFrame column as weights. Rows with larger value in the
`num_specimen_seen` column are more likely to be sampled.
>>> df.sample(n=2, weights='num_specimen_seen', random_state=1)
num_legs num_wings num_specimen_seen
falcon 2 2 10
fish 0 0 8
"""
if axis is None:
axis = self._stat_axis_number
axis = self._get_axis_number(axis)
axis_length = self.shape[axis]
# Process random_state argument
rs = com.random_state(random_state)
# Check weights for compliance
if weights is not None:
# If a series, align with frame
if isinstance(weights, ABCSeries):
weights = weights.reindex(self.axes[axis])
# Strings acceptable if a dataframe and axis = 0
if isinstance(weights, str):
if isinstance(self, ABCDataFrame):
if axis == 0:
try:
weights = self[weights]
except KeyError:
raise KeyError(
"String passed to weights not a valid column"
)
else:
raise ValueError(
"Strings can only be passed to "
"weights when sampling from rows on "
"a DataFrame"
)
else:
raise ValueError(
"Strings cannot be passed as weights "
"when sampling from a Series."
)
weights = pd.Series(weights, dtype="float64")
if len(weights) != axis_length:
raise ValueError(
"Weights and axis to be sampled must be of same length"
)
if (weights == np.inf).any() or (weights == -np.inf).any():
raise ValueError("weight vector may not include `inf` values")
if (weights < 0).any():
raise ValueError("weight vector many not include negative values")
# If has nan, set to zero.
weights = weights.fillna(0)
# Renormalize if don't sum to 1
if weights.sum() != 1:
if weights.sum() != 0:
weights = weights / weights.sum()
else:
raise ValueError("Invalid weights: weights sum to zero")
weights = weights.values
# If no frac or n, default to n=1.
if n is None and frac is None:
n = 1
elif frac is not None and frac > 1 and not replace:
raise ValueError(
"Replace has to be set to `True` when "
"upsampling the population `frac` > 1."
)
elif n is not None and frac is None and n % 1 != 0:
raise ValueError("Only integers accepted as `n` values")
elif n is None and frac is not None:
n = int(round(frac * axis_length))
elif n is not None and frac is not None:
raise ValueError("Please enter a value for `frac` OR `n`, not both")
# Check for negative sizes
if n < 0:
raise ValueError(
"A negative number of rows requested. Please provide positive value."
)
locs = rs.choice(axis_length, size=n, replace=replace, p=weights)
return self.take(locs, axis=axis)
_shared_docs[
"pipe"
] = r"""
Apply func(self, \*args, \*\*kwargs).
Parameters
----------
func : function
Function to apply to the %(klass)s.
``args``, and ``kwargs`` are passed into ``func``.
Alternatively a ``(callable, data_keyword)`` tuple where
``data_keyword`` is a string indicating the keyword of
``callable`` that expects the %(klass)s.
args : iterable, optional
Positional arguments passed into ``func``.
kwargs : mapping, optional
A dictionary of keyword arguments passed into ``func``.
Returns
-------
object : the return type of ``func``.
See Also
--------
DataFrame.apply
DataFrame.applymap
Series.map
Notes
-----
Use ``.pipe`` when chaining together functions that expect
Series, DataFrames or GroupBy objects. Instead of writing
>>> f(g(h(df), arg1=a), arg2=b, arg3=c)
You can write
>>> (df.pipe(h)
... .pipe(g, arg1=a)
... .pipe(f, arg2=b, arg3=c)
... )
If you have a function that takes the data as (say) the second
argument, pass a tuple indicating which keyword expects the
data. For example, suppose ``f`` takes its data as ``arg2``:
>>> (df.pipe(h)
... .pipe(g, arg1=a)
... .pipe((f, 'arg2'), arg1=a, arg3=c)
... )
"""
@Appender(_shared_docs["pipe"] % _shared_doc_kwargs)
def pipe(self, func, *args, **kwargs):
return com.pipe(self, func, *args, **kwargs)
_shared_docs["aggregate"] = dedent(
"""
Aggregate using one or more operations over the specified axis.
%(versionadded)s
Parameters
----------
func : function, str, list or dict
Function to use for aggregating the data. If a function, must either
work when passed a %(klass)s or when passed to %(klass)s.apply.
Accepted combinations are:
- function
- string function name
- list of functions and/or function names, e.g. ``[np.sum, 'mean']``
- dict of axis labels -> functions, function names or list of such.
%(axis)s
*args
Positional arguments to pass to `func`.
**kwargs
Keyword arguments to pass to `func`.
Returns
-------
scalar, Series or DataFrame
The return can be:
* scalar : when Series.agg is called with single function
* Series : when DataFrame.agg is called with a single function
* DataFrame : when DataFrame.agg is called with several functions
Return scalar, Series or DataFrame.
%(see_also)s
Notes
-----
`agg` is an alias for `aggregate`. Use the alias.
A passed user-defined-function will be passed a Series for evaluation.
%(examples)s"""
)
_shared_docs[
"transform"
] = """
Call ``func`` on self producing a %(klass)s with transformed values.
Produced %(klass)s will have same axis length as self.
Parameters
----------
func : function, str, list or dict
Function to use for transforming the data. If a function, must either
work when passed a %(klass)s or when passed to %(klass)s.apply.
Accepted combinations are:
- function
- string function name
- list of functions and/or function names, e.g. ``[np.exp. 'sqrt']``
- dict of axis labels -> functions, function names or list of such.
%(axis)s
*args
Positional arguments to pass to `func`.
**kwargs
Keyword arguments to pass to `func`.
Returns
-------
%(klass)s
A %(klass)s that must have the same length as self.
Raises
------
ValueError : If the returned %(klass)s has a different length than self.
See Also
--------
%(klass)s.agg : Only perform aggregating type operations.
%(klass)s.apply : Invoke function on a %(klass)s.
Examples
--------
>>> df = pd.DataFrame({'A': range(3), 'B': range(1, 4)})
>>> df
A B
0 0 1
1 1 2
2 2 3
>>> df.transform(lambda x: x + 1)
A B
0 1 2
1 2 3
2 3 4
Even though the resulting %(klass)s must have the same length as the
input %(klass)s, it is possible to provide several input functions:
>>> s = pd.Series(range(3))
>>> s
0 0
1 1
2 2
dtype: int64
>>> s.transform([np.sqrt, np.exp])
sqrt exp
0 0.000000 1.000000
1 1.000000 2.718282
2 1.414214 7.389056
"""
# ----------------------------------------------------------------------
# Attribute access
def __finalize__(
self: FrameOrSeries, other, method=None, **kwargs
) -> FrameOrSeries:
"""
Propagate metadata from other to self.
Parameters
----------
other : the object from which to get the attributes that we are going
to propagate
method : optional, a passed method name ; possibly to take different
types of propagation actions based on this
"""
if isinstance(other, NDFrame):
for name in other.attrs:
self.attrs[name] = other.attrs[name]
# For subclasses using _metadata.
for name in self._metadata:
assert isinstance(name, str)
object.__setattr__(self, name, getattr(other, name, None))
return self
def __getattr__(self, name: str):
"""
After regular attribute access, try looking up the name
This allows simpler access to columns for interactive use.
"""
# Note: obj.x will always call obj.__getattribute__('x') prior to
# calling obj.__getattr__('x').
if (
name in self._internal_names_set
or name in self._metadata
or name in self._accessors
):
return object.__getattribute__(self, name)
else:
if self._info_axis._can_hold_identifiers_and_holds_name(name):
return self[name]
return object.__getattribute__(self, name)
def __setattr__(self, name: str, value) -> None:
"""
After regular attribute access, try setting the name
This allows simpler access to columns for interactive use.
"""
# first try regular attribute access via __getattribute__, so that
# e.g. ``obj.x`` and ``obj.x = 4`` will always reference/modify
# the same attribute.
try:
object.__getattribute__(self, name)
return object.__setattr__(self, name, value)
except AttributeError:
pass
# if this fails, go on to more involved attribute setting
# (note that this matches __getattr__, above).
if name in self._internal_names_set:
object.__setattr__(self, name, value)
elif name in self._metadata:
object.__setattr__(self, name, value)
else:
try:
existing = getattr(self, name)
if isinstance(existing, Index):
object.__setattr__(self, name, value)
elif name in self._info_axis:
self[name] = value
else:
object.__setattr__(self, name, value)
except (AttributeError, TypeError):
if isinstance(self, ABCDataFrame) and (is_list_like(value)):
warnings.warn(
"Pandas doesn't allow columns to be "
"created via a new attribute name - see "
"https://pandas.pydata.org/pandas-docs/"
"stable/indexing.html#attribute-access",
stacklevel=2,
)
object.__setattr__(self, name, value)
def _dir_additions(self):
"""
add the string-like attributes from the info_axis.
If info_axis is a MultiIndex, it's first level values are used.
"""
additions = {
c
for c in self._info_axis.unique(level=0)[:100]
if isinstance(c, str) and c.isidentifier()
}
return super()._dir_additions().union(additions)
# ----------------------------------------------------------------------
# Consolidation of internals
def _protect_consolidate(self, f):
"""
Consolidate _data -- if the blocks have changed, then clear the
cache
"""
blocks_before = len(self._data.blocks)
result = f()
if len(self._data.blocks) != blocks_before:
self._clear_item_cache()
return result
def _consolidate_inplace(self) -> None:
"""Consolidate data in place and return None"""
def f():
self._data = self._data.consolidate()
self._protect_consolidate(f)
def _consolidate(self, inplace: bool_t = False):
"""
Compute NDFrame with "consolidated" internals (data of each dtype
grouped together in a single ndarray).
Parameters
----------
inplace : bool, default False
If False return new object, otherwise modify existing object.
Returns
-------
consolidated : same type as caller
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if inplace:
self._consolidate_inplace()
else:
f = lambda: self._data.consolidate()
cons_data = self._protect_consolidate(f)
return self._constructor(cons_data).__finalize__(self)
@property
def _is_mixed_type(self):
f = lambda: self._data.is_mixed_type
return self._protect_consolidate(f)
@property
def _is_numeric_mixed_type(self):
f = lambda: self._data.is_numeric_mixed_type
return self._protect_consolidate(f)
def _check_inplace_setting(self, value) -> bool_t:
""" check whether we allow in-place setting with this type of value """
if self._is_mixed_type:
if not self._is_numeric_mixed_type:
# allow an actual np.nan thru
if is_float(value) and np.isnan(value):
return True
raise TypeError(
"Cannot do inplace boolean setting on "
"mixed-types with a non np.nan value"
)
return True
def _get_numeric_data(self):
return self._constructor(self._data.get_numeric_data()).__finalize__(self)
def _get_bool_data(self):
return self._constructor(self._data.get_bool_data()).__finalize__(self)
# ----------------------------------------------------------------------
# Internal Interface Methods
@property
def values(self) -> np.ndarray:
"""
Return a Numpy representation of the DataFrame.
.. warning::
We recommend using :meth:`DataFrame.to_numpy` instead.
Only the values in the DataFrame will be returned, the axes labels
will be removed.
Returns
-------
numpy.ndarray
The values of the DataFrame.
See Also
--------
DataFrame.to_numpy : Recommended alternative to this method.
DataFrame.index : Retrieve the index labels.
DataFrame.columns : Retrieving the column names.
Notes
-----
The dtype will be a lower-common-denominator dtype (implicit
upcasting); that is to say if the dtypes (even of numeric types)
are mixed, the one that accommodates all will be chosen. Use this
with care if you are not dealing with the blocks.
e.g. If the dtypes are float16 and float32, dtype will be upcast to
float32. If dtypes are int32 and uint8, dtype will be upcast to
int32. By :func:`numpy.find_common_type` convention, mixing int64
and uint64 will result in a float64 dtype.
Examples
--------
A DataFrame where all columns are the same type (e.g., int64) results
in an array of the same type.
>>> df = pd.DataFrame({'age': [ 3, 29],
... 'height': [94, 170],
... 'weight': [31, 115]})
>>> df
age height weight
0 3 94 31
1 29 170 115
>>> df.dtypes
age int64
height int64
weight int64
dtype: object
>>> df.values
array([[ 3, 94, 31],
[ 29, 170, 115]], dtype=int64)
A DataFrame with mixed type columns(e.g., str/object, int64, float32)
results in an ndarray of the broadest type that accommodates these
mixed types (e.g., object).
>>> df2 = pd.DataFrame([('parrot', 24.0, 'second'),
... ('lion', 80.5, 1),
... ('monkey', np.nan, None)],
... columns=('name', 'max_speed', 'rank'))
>>> df2.dtypes
name object
max_speed float64
rank object
dtype: object
>>> df2.values
array([['parrot', 24.0, 'second'],
['lion', 80.5, 1],
['monkey', nan, None]], dtype=object)
"""
self._consolidate_inplace()
return self._data.as_array(transpose=self._AXIS_REVERSED)
@property
def _values(self) -> np.ndarray:
"""internal implementation"""
return self.values
def _internal_get_values(self) -> np.ndarray:
"""
Return an ndarray after converting sparse values to dense.
This is the same as ``.values`` for non-sparse data. For sparse
data contained in a `SparseArray`, the data are first
converted to a dense representation.
Returns
-------
numpy.ndarray
Numpy representation of DataFrame.
See Also
--------
values : Numpy representation of DataFrame.
SparseArray : Container for sparse data.
"""
return self.values
@property
def dtypes(self):
"""
Return the dtypes in the DataFrame.
This returns a Series with the data type of each column.
The result's index is the original DataFrame's columns. Columns
with mixed types are stored with the ``object`` dtype. See
:ref:`the User Guide <basics.dtypes>` for more.
Returns
-------
pandas.Series
The data type of each column.
Examples
--------
>>> df = pd.DataFrame({'float': [1.0],
... 'int': [1],
... 'datetime': [pd.Timestamp('20180310')],
... 'string': ['foo']})
>>> df.dtypes
float float64
int int64
datetime datetime64[ns]
string object
dtype: object
"""
from pandas import Series
return Series(self._data.get_dtypes(), index=self._info_axis, dtype=np.object_)
def _to_dict_of_blocks(self, copy: bool_t = True):
"""
Return a dict of dtype -> Constructor Types that
each is a homogeneous dtype.
Internal ONLY
"""
return {
k: self._constructor(v).__finalize__(self)
for k, v, in self._data.to_dict(copy=copy).items()
}
def astype(
self: FrameOrSeries, dtype, copy: bool_t = True, errors: str = "raise"
) -> FrameOrSeries:
"""
Cast a pandas object to a specified dtype ``dtype``.
Parameters
----------
dtype : data type, or dict of column name -> data type
Use a numpy.dtype or Python type to cast entire pandas object to
the same type. Alternatively, use {col: dtype, ...}, where col is a
column label and dtype is a numpy.dtype or Python type to cast one
or more of the DataFrame's columns to column-specific types.
copy : bool, default True
Return a copy when ``copy=True`` (be very careful setting
``copy=False`` as changes to values then may propagate to other
pandas objects).
errors : {'raise', 'ignore'}, default 'raise'
Control raising of exceptions on invalid data for provided dtype.
- ``raise`` : allow exceptions to be raised
- ``ignore`` : suppress exceptions. On error return original object.
Returns
-------
casted : same type as caller
See Also
--------
to_datetime : Convert argument to datetime.
to_timedelta : Convert argument to timedelta.
to_numeric : Convert argument to a numeric type.
numpy.ndarray.astype : Cast a numpy array to a specified type.
Examples
--------
Create a DataFrame:
>>> d = {'col1': [1, 2], 'col2': [3, 4]}
>>> df = pd.DataFrame(data=d)
>>> df.dtypes
col1 int64
col2 int64
dtype: object
Cast all columns to int32:
>>> df.astype('int32').dtypes
col1 int32
col2 int32
dtype: object
Cast col1 to int32 using a dictionary:
>>> df.astype({'col1': 'int32'}).dtypes
col1 int32
col2 int64
dtype: object
Create a series:
>>> ser = pd.Series([1, 2], dtype='int32')
>>> ser
0 1
1 2
dtype: int32
>>> ser.astype('int64')
0 1
1 2
dtype: int64
Convert to categorical type:
>>> ser.astype('category')
0 1
1 2
dtype: category
Categories (2, int64): [1, 2]
Convert to ordered categorical type with custom ordering:
>>> cat_dtype = pd.api.types.CategoricalDtype(
... categories=[2, 1], ordered=True)
>>> ser.astype(cat_dtype)
0 1
1 2
dtype: category
Categories (2, int64): [2 < 1]
Note that using ``copy=False`` and changing data on a new
pandas object may propagate changes:
>>> s1 = pd.Series([1, 2])
>>> s2 = s1.astype('int64', copy=False)
>>> s2[0] = 10
>>> s1 # note that s1[0] has changed too
0 10
1 2
dtype: int64
"""
if is_dict_like(dtype):
if self.ndim == 1: # i.e. Series
if len(dtype) > 1 or self.name not in dtype:
raise KeyError(
"Only the Series name can be used for "
"the key in Series dtype mappings."
)
new_type = dtype[self.name]
return self.astype(new_type, copy, errors)
for col_name in dtype.keys():
if col_name not in self:
raise KeyError(
"Only a column name can be used for the "
"key in a dtype mappings argument."
)
results = []
for col_name, col in self.items():
if col_name in dtype:
results.append(
col.astype(dtype=dtype[col_name], copy=copy, errors=errors)
)
else:
results.append(col.copy() if copy else col)
elif is_extension_array_dtype(dtype) and self.ndim > 1:
# GH 18099/22869: columnwise conversion to extension dtype
# GH 24704: use iloc to handle duplicate column names
results = [
self.iloc[:, i].astype(dtype, copy=copy)
for i in range(len(self.columns))
]
else:
# else, only a single dtype is given
new_data = self._data.astype(dtype=dtype, copy=copy, errors=errors)
return self._constructor(new_data).__finalize__(self)
# GH 19920: retain column metadata after concat
result = pd.concat(results, axis=1, copy=False)
result.columns = self.columns
return result
def copy(self: FrameOrSeries, deep: bool_t = True) -> FrameOrSeries:
"""
Make a copy of this object's indices and data.
When ``deep=True`` (default), a new object will be created with a
copy of the calling object's data and indices. Modifications to
the data or indices of the copy will not be reflected in the
original object (see notes below).
When ``deep=False``, a new object will be created without copying
the calling object's data or index (only references to the data
and index are copied). Any changes to the data of the original
will be reflected in the shallow copy (and vice versa).
Parameters
----------
deep : bool, default True
Make a deep copy, including a copy of the data and the indices.
With ``deep=False`` neither the indices nor the data are copied.
Returns
-------
copy : Series or DataFrame
Object type matches caller.
Notes
-----
When ``deep=True``, data is copied but actual Python objects
will not be copied recursively, only the reference to the object.
This is in contrast to `copy.deepcopy` in the Standard Library,
which recursively copies object data (see examples below).
While ``Index`` objects are copied when ``deep=True``, the underlying
numpy array is not copied for performance reasons. Since ``Index`` is
immutable, the underlying data can be safely shared and a copy
is not needed.
Examples
--------
>>> s = pd.Series([1, 2], index=["a", "b"])
>>> s
a 1
b 2
dtype: int64
>>> s_copy = s.copy()
>>> s_copy
a 1
b 2
dtype: int64
**Shallow copy versus default (deep) copy:**
>>> s = pd.Series([1, 2], index=["a", "b"])
>>> deep = s.copy()
>>> shallow = s.copy(deep=False)
Shallow copy shares data and index with original.
>>> s is shallow
False
>>> s.values is shallow.values and s.index is shallow.index
True
Deep copy has own copy of data and index.
>>> s is deep
False
>>> s.values is deep.values or s.index is deep.index
False
Updates to the data shared by shallow copy and original is reflected
in both; deep copy remains unchanged.
>>> s[0] = 3
>>> shallow[1] = 4
>>> s
a 3
b 4
dtype: int64
>>> shallow
a 3
b 4
dtype: int64
>>> deep
a 1
b 2
dtype: int64
Note that when copying an object containing Python objects, a deep copy
will copy the data, but will not do so recursively. Updating a nested
data object will be reflected in the deep copy.
>>> s = pd.Series([[1, 2], [3, 4]])
>>> deep = s.copy()
>>> s[0][0] = 10
>>> s
0 [10, 2]
1 [3, 4]
dtype: object
>>> deep
0 [10, 2]
1 [3, 4]
dtype: object
"""
data = self._data.copy(deep=deep)
return self._constructor(data).__finalize__(self)
def __copy__(self: FrameOrSeries, deep: bool_t = True) -> FrameOrSeries:
return self.copy(deep=deep)
def __deepcopy__(self: FrameOrSeries, memo=None) -> FrameOrSeries:
"""
Parameters
----------
memo, default None
Standard signature. Unused
"""
return self.copy(deep=True)
def _convert(
self: FrameOrSeries,
datetime: bool_t = False,
numeric: bool_t = False,
timedelta: bool_t = False,
coerce: bool_t = False,
copy: bool_t = True,
) -> FrameOrSeries:
"""
Attempt to infer better dtype for object columns
Parameters
----------
datetime : bool, default False
If True, convert to date where possible.
numeric : bool, default False
If True, attempt to convert to numbers (including strings), with
unconvertible values becoming NaN.
timedelta : bool, default False
If True, convert to timedelta where possible.
coerce : bool, default False
If True, force conversion with unconvertible values converted to
nulls (NaN or NaT).
copy : bool, default True
If True, return a copy even if no copy is necessary (e.g. no
conversion was done). Note: This is meant for internal use, and
should not be confused with inplace.
Returns
-------
converted : same as input object
"""
validate_bool_kwarg(datetime, "datetime")
validate_bool_kwarg(numeric, "numeric")
validate_bool_kwarg(timedelta, "timedelta")
validate_bool_kwarg(coerce, "coerce")
validate_bool_kwarg(copy, "copy")
return self._constructor(
self._data.convert(
datetime=datetime,
numeric=numeric,
timedelta=timedelta,
coerce=coerce,
copy=copy,
)
).__finalize__(self)
def infer_objects(self: FrameOrSeries) -> FrameOrSeries:
"""
Attempt to infer better dtypes for object columns.
Attempts soft conversion of object-dtyped
columns, leaving non-object and unconvertible
columns unchanged. The inference rules are the
same as during normal Series/DataFrame construction.
.. versionadded:: 0.21.0
Returns
-------
converted : same type as input object
See Also
--------
to_datetime : Convert argument to datetime.
to_timedelta : Convert argument to timedelta.
to_numeric : Convert argument to numeric type.
convert_dtypes : Convert argument to best possible dtype.
Examples
--------
>>> df = pd.DataFrame({"A": ["a", 1, 2, 3]})
>>> df = df.iloc[1:]
>>> df
A
1 1
2 2
3 3
>>> df.dtypes
A object
dtype: object
>>> df.infer_objects().dtypes
A int64
dtype: object
"""
# numeric=False necessary to only soft convert;
# python objects will still be converted to
# native numpy numeric types
return self._constructor(
self._data.convert(
datetime=True, numeric=False, timedelta=True, coerce=False, copy=True
)
).__finalize__(self)
def convert_dtypes(
self: FrameOrSeries,
infer_objects: bool_t = True,
convert_string: bool_t = True,
convert_integer: bool_t = True,
convert_boolean: bool_t = True,
) -> FrameOrSeries:
"""
Convert columns to best possible dtypes using dtypes supporting ``pd.NA``.
.. versionadded:: 1.0.0
Parameters
----------
infer_objects : bool, default True
Whether object dtypes should be converted to the best possible types.
convert_string : bool, default True
Whether object dtypes should be converted to ``StringDtype()``.
convert_integer : bool, default True
Whether, if possible, conversion can be done to integer extension types.
convert_boolean : bool, defaults True
Whether object dtypes should be converted to ``BooleanDtypes()``.
Returns
-------
Series or DataFrame
Copy of input object with new dtype.
See Also
--------
infer_objects : Infer dtypes of objects.
to_datetime : Convert argument to datetime.
to_timedelta : Convert argument to timedelta.
to_numeric : Convert argument to a numeric type.
Notes
-----
By default, ``convert_dtypes`` will attempt to convert a Series (or each
Series in a DataFrame) to dtypes that support ``pd.NA``. By using the options
``convert_string``, ``convert_integer``, and ``convert_boolean``, it is
possible to turn off individual conversions to ``StringDtype``, the integer
extension types or ``BooleanDtype``, respectively.
For object-dtyped columns, if ``infer_objects`` is ``True``, use the inference
rules as during normal Series/DataFrame construction. Then, if possible,
convert to ``StringDtype``, ``BooleanDtype`` or an appropriate integer extension
type, otherwise leave as ``object``.
If the dtype is integer, convert to an appropriate integer extension type.
If the dtype is numeric, and consists of all integers, convert to an
appropriate integer extension type.
In the future, as new dtypes are added that support ``pd.NA``, the results
of this method will change to support those new dtypes.
Examples
--------
>>> df = pd.DataFrame(
... {
... "a": pd.Series([1, 2, 3], dtype=np.dtype("int32")),
... "b": pd.Series(["x", "y", "z"], dtype=np.dtype("O")),
... "c": pd.Series([True, False, np.nan], dtype=np.dtype("O")),
... "d": pd.Series(["h", "i", np.nan], dtype=np.dtype("O")),
... "e": pd.Series([10, np.nan, 20], dtype=np.dtype("float")),
... "f": pd.Series([np.nan, 100.5, 200], dtype=np.dtype("float")),
... }
... )
Start with a DataFrame with default dtypes.
>>> df
a b c d e f
0 1 x True h 10.0 NaN
1 2 y False i NaN 100.5
2 3 z NaN NaN 20.0 200.0
>>> df.dtypes
a int32
b object
c object
d object
e float64
f float64
dtype: object
Convert the DataFrame to use best possible dtypes.
>>> dfn = df.convert_dtypes()
>>> dfn
a b c d e f
0 1 x True h 10 NaN
1 2 y False i <NA> 100.5
2 3 z <NA> <NA> 20 200.0
>>> dfn.dtypes
a Int32
b string
c boolean
d string
e Int64
f float64
dtype: object
Start with a Series of strings and missing data represented by ``np.nan``.
>>> s = pd.Series(["a", "b", np.nan])
>>> s
0 a
1 b
2 NaN
dtype: object
Obtain a Series with dtype ``StringDtype``.
>>> s.convert_dtypes()
0 a
1 b
2 <NA>
dtype: string
"""
if self.ndim == 1:
return self._convert_dtypes(
infer_objects, convert_string, convert_integer, convert_boolean
)
else:
results = [
col._convert_dtypes(
infer_objects, convert_string, convert_integer, convert_boolean
)
for col_name, col in self.items()
]
result = pd.concat(results, axis=1, copy=False)
return result
# ----------------------------------------------------------------------
# Filling NA's
@doc(**_shared_doc_kwargs)
def fillna(
self: FrameOrSeries,
value=None,
method=None,
axis=None,
inplace: bool_t = False,
limit=None,
downcast=None,
) -> Optional[FrameOrSeries]:
"""
Fill NA/NaN values using the specified method.
Parameters
----------
value : scalar, dict, Series, or DataFrame
Value to use to fill holes (e.g. 0), alternately a
dict/Series/DataFrame of values specifying which value to use for
each index (for a Series) or column (for a DataFrame). Values not
in the dict/Series/DataFrame will not be filled. This value cannot
be a list.
method : {{'backfill', 'bfill', 'pad', 'ffill', None}}, default None
Method to use for filling holes in reindexed Series
pad / ffill: propagate last valid observation forward to next valid
backfill / bfill: use next valid observation to fill gap.
axis : {axes_single_arg}
Axis along which to fill missing values.
inplace : bool, default False
If True, fill in-place. Note: this will modify any
other views on this object (e.g., a no-copy slice for a column in a
DataFrame).
limit : int, default None
If method is specified, this is the maximum number of consecutive
NaN values to forward/backward fill. In other words, if there is
a gap with more than this number of consecutive NaNs, it will only
be partially filled. If method is not specified, this is the
maximum number of entries along the entire axis where NaNs will be
filled. Must be greater than 0 if not None.
downcast : dict, default is None
A dict of item->dtype of what to downcast if possible,
or the string 'infer' which will try to downcast to an appropriate
equal type (e.g. float64 to int64 if possible).
Returns
-------
{klass} or None
Object with missing values filled or None if ``inplace=True``.
See Also
--------
interpolate : Fill NaN values using interpolation.
reindex : Conform object to new index.
asfreq : Convert TimeSeries to specified frequency.
Examples
--------
>>> df = pd.DataFrame([[np.nan, 2, np.nan, 0],
... [3, 4, np.nan, 1],
... [np.nan, np.nan, np.nan, 5],
... [np.nan, 3, np.nan, 4]],
... columns=list('ABCD'))
>>> df
A B C D
0 NaN 2.0 NaN 0
1 3.0 4.0 NaN 1
2 NaN NaN NaN 5
3 NaN 3.0 NaN 4
Replace all NaN elements with 0s.
>>> df.fillna(0)
A B C D
0 0.0 2.0 0.0 0
1 3.0 4.0 0.0 1
2 0.0 0.0 0.0 5
3 0.0 3.0 0.0 4
We can also propagate non-null values forward or backward.
>>> df.fillna(method='ffill')
A B C D
0 NaN 2.0 NaN 0
1 3.0 4.0 NaN 1
2 3.0 4.0 NaN 5
3 3.0 3.0 NaN 4
Replace all NaN elements in column 'A', 'B', 'C', and 'D', with 0, 1,
2, and 3 respectively.
>>> values = {{'A': 0, 'B': 1, 'C': 2, 'D': 3}}
>>> df.fillna(value=values)
A B C D
0 0.0 2.0 2.0 0
1 3.0 4.0 2.0 1
2 0.0 1.0 2.0 5
3 0.0 3.0 2.0 4
Only replace the first NaN element.
>>> df.fillna(value=values, limit=1)
A B C D
0 0.0 2.0 2.0 0
1 3.0 4.0 NaN 1
2 NaN 1.0 NaN 5
3 NaN 3.0 NaN 4
"""
inplace = validate_bool_kwarg(inplace, "inplace")
value, method = validate_fillna_kwargs(value, method)
self._consolidate_inplace()
# set the default here, so functions examining the signaure
# can detect if something was set (e.g. in groupby) (GH9221)
if axis is None:
axis = 0
axis = self._get_axis_number(axis)
if value is None:
if self._is_mixed_type and axis == 1:
if inplace:
raise NotImplementedError()
result = self.T.fillna(method=method, limit=limit).T
# need to downcast here because of all of the transposes
result._data = result._data.downcast()
return result
new_data = self._data.interpolate(
method=method,
axis=axis,
limit=limit,
inplace=inplace,
coerce=True,
downcast=downcast,
)
else:
if len(self._get_axis(axis)) == 0:
return self
if self.ndim == 1:
if isinstance(value, (dict, ABCSeries)):
value = create_series_with_explicit_dtype(
value, dtype_if_empty=object
)
elif not is_list_like(value):
pass
else:
raise TypeError(
'"value" parameter must be a scalar, dict '
"or Series, but you passed a "
f'"{type(value).__name__}"'
)
new_data = self._data.fillna(
value=value, limit=limit, inplace=inplace, downcast=downcast
)
elif isinstance(value, (dict, ABCSeries)):
if axis == 1:
raise NotImplementedError(
"Currently only can fill "
"with dict/Series column "
"by column"
)
result = self if inplace else self.copy()
for k, v in value.items():
if k not in result:
continue
obj = result[k]
obj.fillna(v, limit=limit, inplace=True, downcast=downcast)
return result if not inplace else None
elif not is_list_like(value):
new_data = self._data.fillna(
value=value, limit=limit, inplace=inplace, downcast=downcast
)
elif isinstance(value, ABCDataFrame) and self.ndim == 2:
new_data = self.where(self.notna(), value)
else:
raise ValueError(f"invalid fill value with a {type(value)}")
if inplace:
self._update_inplace(new_data)
return None
else:
return self._constructor(new_data).__finalize__(self)
def ffill(
self: FrameOrSeries,
axis=None,
inplace: bool_t = False,
limit=None,
downcast=None,
) -> Optional[FrameOrSeries]:
"""
Synonym for :meth:`DataFrame.fillna` with ``method='ffill'``.
Returns
-------
%(klass)s or None
Object with missing values filled or None if ``inplace=True``.
"""
return self.fillna(
method="ffill", axis=axis, inplace=inplace, limit=limit, downcast=downcast
)
def bfill(
self: FrameOrSeries,
axis=None,
inplace: bool_t = False,
limit=None,
downcast=None,
) -> Optional[FrameOrSeries]:
"""
Synonym for :meth:`DataFrame.fillna` with ``method='bfill'``.
Returns
-------
%(klass)s or None
Object with missing values filled or None if ``inplace=True``.
"""
return self.fillna(
method="bfill", axis=axis, inplace=inplace, limit=limit, downcast=downcast
)
_shared_docs[
"replace"
] = """
Replace values given in `to_replace` with `value`.
Values of the %(klass)s are replaced with other values dynamically.
This differs from updating with ``.loc`` or ``.iloc``, which require
you to specify a location to update with some value.
Parameters
----------
to_replace : str, regex, list, dict, Series, int, float, or None
How to find the values that will be replaced.
* numeric, str or regex:
- numeric: numeric values equal to `to_replace` will be
replaced with `value`
- str: string exactly matching `to_replace` will be replaced
with `value`
- regex: regexs matching `to_replace` will be replaced with
`value`
* list of str, regex, or numeric:
- First, if `to_replace` and `value` are both lists, they
**must** be the same length.
- Second, if ``regex=True`` then all of the strings in **both**
lists will be interpreted as regexs otherwise they will match
directly. This doesn't matter much for `value` since there
are only a few possible substitution regexes you can use.
- str, regex and numeric rules apply as above.
* dict:
- Dicts can be used to specify different replacement values
for different existing values. For example,
``{'a': 'b', 'y': 'z'}`` replaces the value 'a' with 'b' and
'y' with 'z'. To use a dict in this way the `value`
parameter should be `None`.
- For a DataFrame a dict can specify that different values
should be replaced in different columns. For example,
``{'a': 1, 'b': 'z'}`` looks for the value 1 in column 'a'
and the value 'z' in column 'b' and replaces these values
with whatever is specified in `value`. The `value` parameter
should not be ``None`` in this case. You can treat this as a
special case of passing two lists except that you are
specifying the column to search in.
- For a DataFrame nested dictionaries, e.g.,
``{'a': {'b': np.nan}}``, are read as follows: look in column
'a' for the value 'b' and replace it with NaN. The `value`
parameter should be ``None`` to use a nested dict in this
way. You can nest regular expressions as well. Note that
column names (the top-level dictionary keys in a nested
dictionary) **cannot** be regular expressions.
* None:
- This means that the `regex` argument must be a string,
compiled regular expression, or list, dict, ndarray or
Series of such elements. If `value` is also ``None`` then
this **must** be a nested dictionary or Series.
See the examples section for examples of each of these.
value : scalar, dict, list, str, regex, default None
Value to replace any values matching `to_replace` with.
For a DataFrame a dict of values can be used to specify which
value to use for each column (columns not in the dict will not be
filled). Regular expressions, strings and lists or dicts of such
objects are also allowed.
inplace : bool, default False
If True, in place. Note: this will modify any
other views on this object (e.g. a column from a DataFrame).
Returns the caller if this is True.
limit : int, default None
Maximum size gap to forward or backward fill.
regex : bool or same types as `to_replace`, default False
Whether to interpret `to_replace` and/or `value` as regular
expressions. If this is ``True`` then `to_replace` *must* be a
string. Alternatively, this could be a regular expression or a
list, dict, or array of regular expressions in which case
`to_replace` must be ``None``.
method : {'pad', 'ffill', 'bfill', `None`}
The method to use when for replacement, when `to_replace` is a
scalar, list or tuple and `value` is ``None``.
.. versionchanged:: 0.23.0
Added to DataFrame.
Returns
-------
%(klass)s
Object after replacement.
Raises
------
AssertionError
* If `regex` is not a ``bool`` and `to_replace` is not
``None``.
TypeError
* If `to_replace` is a ``dict`` and `value` is not a ``list``,
``dict``, ``ndarray``, or ``Series``
* If `to_replace` is ``None`` and `regex` is not compilable
into a regular expression or is a list, dict, ndarray, or
Series.
* When replacing multiple ``bool`` or ``datetime64`` objects and
the arguments to `to_replace` does not match the type of the
value being replaced
ValueError
* If a ``list`` or an ``ndarray`` is passed to `to_replace` and
`value` but they are not the same length.
See Also
--------
%(klass)s.fillna : Fill NA values.
%(klass)s.where : Replace values based on boolean condition.
Series.str.replace : Simple string replacement.
Notes
-----
* Regex substitution is performed under the hood with ``re.sub``. The
rules for substitution for ``re.sub`` are the same.
* Regular expressions will only substitute on strings, meaning you
cannot provide, for example, a regular expression matching floating
point numbers and expect the columns in your frame that have a
numeric dtype to be matched. However, if those floating point
numbers *are* strings, then you can do this.
* This method has *a lot* of options. You are encouraged to experiment
and play with this method to gain intuition about how it works.
* When dict is used as the `to_replace` value, it is like
key(s) in the dict are the to_replace part and
value(s) in the dict are the value parameter.
Examples
--------
**Scalar `to_replace` and `value`**
>>> s = pd.Series([0, 1, 2, 3, 4])
>>> s.replace(0, 5)
0 5
1 1
2 2
3 3
4 4
dtype: int64
>>> df = pd.DataFrame({'A': [0, 1, 2, 3, 4],
... 'B': [5, 6, 7, 8, 9],
... 'C': ['a', 'b', 'c', 'd', 'e']})
>>> df.replace(0, 5)
A B C
0 5 5 a
1 1 6 b
2 2 7 c
3 3 8 d
4 4 9 e
**List-like `to_replace`**
>>> df.replace([0, 1, 2, 3], 4)
A B C
0 4 5 a
1 4 6 b
2 4 7 c
3 4 8 d
4 4 9 e
>>> df.replace([0, 1, 2, 3], [4, 3, 2, 1])
A B C
0 4 5 a
1 3 6 b
2 2 7 c
3 1 8 d
4 4 9 e
>>> s.replace([1, 2], method='bfill')
0 0
1 3
2 3
3 3
4 4
dtype: int64
**dict-like `to_replace`**
>>> df.replace({0: 10, 1: 100})
A B C
0 10 5 a
1 100 6 b
2 2 7 c
3 3 8 d
4 4 9 e
>>> df.replace({'A': 0, 'B': 5}, 100)
A B C
0 100 100 a
1 1 6 b
2 2 7 c
3 3 8 d
4 4 9 e
>>> df.replace({'A': {0: 100, 4: 400}})
A B C
0 100 5 a
1 1 6 b
2 2 7 c
3 3 8 d
4 400 9 e
**Regular expression `to_replace`**
>>> df = pd.DataFrame({'A': ['bat', 'foo', 'bait'],
... 'B': ['abc', 'bar', 'xyz']})
>>> df.replace(to_replace=r'^ba.$', value='new', regex=True)
A B
0 new abc
1 foo new
2 bait xyz
>>> df.replace({'A': r'^ba.$'}, {'A': 'new'}, regex=True)
A B
0 new abc
1 foo bar
2 bait xyz
>>> df.replace(regex=r'^ba.$', value='new')
A B
0 new abc
1 foo new
2 bait xyz
>>> df.replace(regex={r'^ba.$': 'new', 'foo': 'xyz'})
A B
0 new abc
1 xyz new
2 bait xyz
>>> df.replace(regex=[r'^ba.$', 'foo'], value='new')
A B
0 new abc
1 new new
2 bait xyz
Note that when replacing multiple ``bool`` or ``datetime64`` objects,
the data types in the `to_replace` parameter must match the data
type of the value being replaced:
>>> df = pd.DataFrame({'A': [True, False, True],
... 'B': [False, True, False]})
>>> df.replace({'a string': 'new value', True: False}) # raises
Traceback (most recent call last):
...
TypeError: Cannot compare types 'ndarray(dtype=bool)' and 'str'
This raises a ``TypeError`` because one of the ``dict`` keys is not of
the correct type for replacement.
Compare the behavior of ``s.replace({'a': None})`` and
``s.replace('a', None)`` to understand the peculiarities
of the `to_replace` parameter:
>>> s = pd.Series([10, 'a', 'a', 'b', 'a'])
When one uses a dict as the `to_replace` value, it is like the
value(s) in the dict are equal to the `value` parameter.
``s.replace({'a': None})`` is equivalent to
``s.replace(to_replace={'a': None}, value=None, method=None)``:
>>> s.replace({'a': None})
0 10
1 None
2 None
3 b
4 None
dtype: object
When ``value=None`` and `to_replace` is a scalar, list or
tuple, `replace` uses the method parameter (default 'pad') to do the
replacement. So this is why the 'a' values are being replaced by 10
in rows 1 and 2 and 'b' in row 4 in this case.
The command ``s.replace('a', None)`` is actually equivalent to
``s.replace(to_replace='a', value=None, method='pad')``:
>>> s.replace('a', None)
0 10
1 10
2 10
3 b
4 b
dtype: object
"""
@Appender(_shared_docs["replace"] % _shared_doc_kwargs)
def replace(
self,
to_replace=None,
value=None,
inplace=False,
limit=None,
regex=False,
method="pad",
):
inplace = validate_bool_kwarg(inplace, "inplace")
if not is_bool(regex) and to_replace is not None:
raise AssertionError("'to_replace' must be 'None' if 'regex' is not a bool")
self._consolidate_inplace()
if value is None:
# passing a single value that is scalar like
# when value is None (GH5319), for compat
if not is_dict_like(to_replace) and not is_dict_like(regex):
to_replace = [to_replace]
if isinstance(to_replace, (tuple, list)):
if isinstance(self, ABCDataFrame):
return self.apply(
_single_replace, args=(to_replace, method, inplace, limit)
)
return _single_replace(self, to_replace, method, inplace, limit)
if not is_dict_like(to_replace):
if not is_dict_like(regex):
raise TypeError(
'If "to_replace" and "value" are both None '
'and "to_replace" is not a list, then '
"regex must be a mapping"
)
to_replace = regex
regex = True
items = list(to_replace.items())
keys, values = zip(*items) if items else ([], [])
are_mappings = [is_dict_like(v) for v in values]
if any(are_mappings):
if not all(are_mappings):
raise TypeError(
"If a nested mapping is passed, all values "
"of the top level mapping must be mappings"
)
# passed a nested dict/Series
to_rep_dict = {}
value_dict = {}
for k, v in items:
keys, values = list(zip(*v.items())) or ([], [])
to_rep_dict[k] = list(keys)
value_dict[k] = list(values)
to_replace, value = to_rep_dict, value_dict
else:
to_replace, value = keys, values
return self.replace(
to_replace, value, inplace=inplace, limit=limit, regex=regex
)
else:
# need a non-zero len on all axes
if not self.size:
return self
new_data = self._data
if is_dict_like(to_replace):
if is_dict_like(value): # {'A' : NA} -> {'A' : 0}
res = self if inplace else self.copy()
for c, src in to_replace.items():
if c in value and c in self:
# object conversion is handled in
# series.replace which is called recursively
res[c] = res[c].replace(
to_replace=src,
value=value[c],
inplace=False,
regex=regex,
)
return None if inplace else res
# {'A': NA} -> 0
elif not is_list_like(value):
keys = [(k, src) for k, src in to_replace.items() if k in self]
keys_len = len(keys) - 1
for i, (k, src) in enumerate(keys):
convert = i == keys_len
new_data = new_data.replace(
to_replace=src,
value=value,
filter=[k],
inplace=inplace,
regex=regex,
convert=convert,
)
else:
raise TypeError("value argument must be scalar, dict, or Series")
elif is_list_like(to_replace): # [NA, ''] -> [0, 'missing']
if is_list_like(value):
if len(to_replace) != len(value):
raise ValueError(
f"Replacement lists must match in length. "
f"Expecting {len(to_replace)} got {len(value)} "
)
new_data = self._data.replace_list(
src_list=to_replace,
dest_list=value,
inplace=inplace,
regex=regex,
)
else: # [NA, ''] -> 0
new_data = self._data.replace(
to_replace=to_replace, value=value, inplace=inplace, regex=regex
)
elif to_replace is None:
if not (
is_re_compilable(regex)
or is_list_like(regex)
or is_dict_like(regex)
):
raise TypeError(
f"'regex' must be a string or a compiled regular expression "
f"or a list or dict of strings or regular expressions, "
f"you passed a {repr(type(regex).__name__)}"
)
return self.replace(
regex, value, inplace=inplace, limit=limit, regex=True
)
else:
# dest iterable dict-like
if is_dict_like(value): # NA -> {'A' : 0, 'B' : -1}
new_data = self._data
for k, v in value.items():
if k in self:
new_data = new_data.replace(
to_replace=to_replace,
value=v,
filter=[k],
inplace=inplace,
regex=regex,
)
elif not is_list_like(value): # NA -> 0
new_data = self._data.replace(
to_replace=to_replace, value=value, inplace=inplace, regex=regex
)
else:
raise TypeError(
f'Invalid "to_replace" type: {repr(type(to_replace).__name__)}'
)
if inplace:
self._update_inplace(new_data)
else:
return self._constructor(new_data).__finalize__(self)
_shared_docs[
"interpolate"
] = """
Please note that only ``method='linear'`` is supported for
DataFrame/Series with a MultiIndex.
Parameters
----------
method : str, default 'linear'
Interpolation technique to use. One of:
* 'linear': Ignore the index and treat the values as equally
spaced. This is the only method supported on MultiIndexes.
* 'time': Works on daily and higher resolution data to interpolate
given length of interval.
* 'index', 'values': use the actual numerical values of the index.
* 'pad': Fill in NaNs using existing values.
* 'nearest', 'zero', 'slinear', 'quadratic', 'cubic', 'spline',
'barycentric', 'polynomial': Passed to
`scipy.interpolate.interp1d`. These methods use the numerical
values of the index. Both 'polynomial' and 'spline' require that
you also specify an `order` (int), e.g.
``df.interpolate(method='polynomial', order=5)``.
* 'krogh', 'piecewise_polynomial', 'spline', 'pchip', 'akima':
Wrappers around the SciPy interpolation methods of similar
names. See `Notes`.
* 'from_derivatives': Refers to
`scipy.interpolate.BPoly.from_derivatives` which
replaces 'piecewise_polynomial' interpolation method in
scipy 0.18.
axis : {0 or 'index', 1 or 'columns', None}, default None
Axis to interpolate along.
limit : int, optional
Maximum number of consecutive NaNs to fill. Must be greater than
0.
inplace : bool, default False
Update the data in place if possible.
limit_direction : {'forward', 'backward', 'both'}, default 'forward'
If limit is specified, consecutive NaNs will be filled in this
direction.
limit_area : {`None`, 'inside', 'outside'}, default None
If limit is specified, consecutive NaNs will be filled with this
restriction.
* ``None``: No fill restriction.
* 'inside': Only fill NaNs surrounded by valid values
(interpolate).
* 'outside': Only fill NaNs outside valid values (extrapolate).
.. versionadded:: 0.23.0
downcast : optional, 'infer' or None, defaults to None
Downcast dtypes if possible.
**kwargs
Keyword arguments to pass on to the interpolating function.
Returns
-------
Series or DataFrame
Returns the same object type as the caller, interpolated at
some or all ``NaN`` values.
See Also
--------
fillna : Fill missing values using different methods.
scipy.interpolate.Akima1DInterpolator : Piecewise cubic polynomials
(Akima interpolator).
scipy.interpolate.BPoly.from_derivatives : Piecewise polynomial in the
Bernstein basis.
scipy.interpolate.interp1d : Interpolate a 1-D function.
scipy.interpolate.KroghInterpolator : Interpolate polynomial (Krogh
interpolator).
scipy.interpolate.PchipInterpolator : PCHIP 1-d monotonic cubic
interpolation.
scipy.interpolate.CubicSpline : Cubic spline data interpolator.
Notes
-----
The 'krogh', 'piecewise_polynomial', 'spline', 'pchip' and 'akima'
methods are wrappers around the respective SciPy implementations of
similar names. These use the actual numerical values of the index.
For more information on their behavior, see the
`SciPy documentation
<https://docs.scipy.org/doc/scipy/reference/interpolate.html#univariate-interpolation>`__
and `SciPy tutorial
<https://docs.scipy.org/doc/scipy/reference/tutorial/interpolate.html>`__.
Examples
--------
Filling in ``NaN`` in a :class:`~pandas.Series` via linear
interpolation.
>>> s = pd.Series([0, 1, np.nan, 3])
>>> s
0 0.0
1 1.0
2 NaN
3 3.0
dtype: float64
>>> s.interpolate()
0 0.0
1 1.0
2 2.0
3 3.0
dtype: float64
Filling in ``NaN`` in a Series by padding, but filling at most two
consecutive ``NaN`` at a time.
>>> s = pd.Series([np.nan, "single_one", np.nan,
... "fill_two_more", np.nan, np.nan, np.nan,
... 4.71, np.nan])
>>> s
0 NaN
1 single_one
2 NaN
3 fill_two_more
4 NaN
5 NaN
6 NaN
7 4.71
8 NaN
dtype: object
>>> s.interpolate(method='pad', limit=2)
0 NaN
1 single_one
2 single_one
3 fill_two_more
4 fill_two_more
5 fill_two_more
6 NaN
7 4.71
8 4.71
dtype: object
Filling in ``NaN`` in a Series via polynomial interpolation or splines:
Both 'polynomial' and 'spline' methods require that you also specify
an ``order`` (int).
>>> s = pd.Series([0, 2, np.nan, 8])
>>> s.interpolate(method='polynomial', order=2)
0 0.000000
1 2.000000
2 4.666667
3 8.000000
dtype: float64
Fill the DataFrame forward (that is, going down) along each column
using linear interpolation.
Note how the last entry in column 'a' is interpolated differently,
because there is no entry after it to use for interpolation.
Note how the first entry in column 'b' remains ``NaN``, because there
is no entry before it to use for interpolation.
>>> df = pd.DataFrame([(0.0, np.nan, -1.0, 1.0),
... (np.nan, 2.0, np.nan, np.nan),
... (2.0, 3.0, np.nan, 9.0),
... (np.nan, 4.0, -4.0, 16.0)],
... columns=list('abcd'))
>>> df
a b c d
0 0.0 NaN -1.0 1.0
1 NaN 2.0 NaN NaN
2 2.0 3.0 NaN 9.0
3 NaN 4.0 -4.0 16.0
>>> df.interpolate(method='linear', limit_direction='forward', axis=0)
a b c d
0 0.0 NaN -1.0 1.0
1 1.0 2.0 -2.0 5.0
2 2.0 3.0 -3.0 9.0
3 2.0 4.0 -4.0 16.0
Using polynomial interpolation.
>>> df['d'].interpolate(method='polynomial', order=2)
0 1.0
1 4.0
2 9.0
3 16.0
Name: d, dtype: float64
"""
@Appender(_shared_docs["interpolate"] % _shared_doc_kwargs)
def interpolate(
self,
method="linear",
axis=0,
limit=None,
inplace=False,
limit_direction="forward",
limit_area=None,
downcast=None,
**kwargs,
):
"""
Interpolate values according to different methods.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
axis = self._get_axis_number(axis)
if axis == 0:
ax = self._info_axis_name
_maybe_transposed_self = self
elif axis == 1:
_maybe_transposed_self = self.T
ax = 1
ax = _maybe_transposed_self._get_axis_number(ax)
if _maybe_transposed_self.ndim == 2:
alt_ax = 1 - ax
else:
alt_ax = ax
if isinstance(_maybe_transposed_self.index, MultiIndex) and method != "linear":
raise ValueError(
"Only `method=linear` interpolation is supported on MultiIndexes."
)
if _maybe_transposed_self._data.get_dtype_counts().get("object") == len(
_maybe_transposed_self.T
):
raise TypeError(
"Cannot interpolate with all object-dtype columns "
"in the DataFrame. Try setting at least one "
"column to a numeric dtype."
)
# create/use the index
if method == "linear":
# prior default
index = np.arange(len(_maybe_transposed_self._get_axis(alt_ax)))
else:
index = _maybe_transposed_self._get_axis(alt_ax)
methods = {"index", "values", "nearest", "time"}
is_numeric_or_datetime = (
is_numeric_dtype(index)
or is_datetime64_any_dtype(index)
or is_timedelta64_dtype(index)
)
if method not in methods and not is_numeric_or_datetime:
raise ValueError(
"Index column must be numeric or datetime type when "
f"using {method} method other than linear. "
"Try setting a numeric or datetime index column before "
"interpolating."
)
if isna(index).any():
raise NotImplementedError(
"Interpolation with NaNs in the index "
"has not been implemented. Try filling "
"those NaNs before interpolating."
)
data = _maybe_transposed_self._data
new_data = data.interpolate(
method=method,
axis=ax,
index=index,
values=_maybe_transposed_self,
limit=limit,
limit_direction=limit_direction,
limit_area=limit_area,
inplace=inplace,
downcast=downcast,
**kwargs,
)
if inplace:
if axis == 1:
new_data = self._constructor(new_data).T._data
self._update_inplace(new_data)
else:
res = self._constructor(new_data).__finalize__(self)
if axis == 1:
res = res.T
return res
# ----------------------------------------------------------------------
# Timeseries methods Methods
def asof(self, where, subset=None):
"""
Return the last row(s) without any NaNs before `where`.
The last row (for each element in `where`, if list) without any
NaN is taken.
In case of a :class:`~pandas.DataFrame`, the last row without NaN
considering only the subset of columns (if not `None`)
If there is no good value, NaN is returned for a Series or
a Series of NaN values for a DataFrame
Parameters
----------
where : date or array-like of dates
Date(s) before which the last row(s) are returned.
subset : str or array-like of str, default `None`
For DataFrame, if not `None`, only use these columns to
check for NaNs.
Returns
-------
scalar, Series, or DataFrame
The return can be:
* scalar : when `self` is a Series and `where` is a scalar
* Series: when `self` is a Series and `where` is an array-like,
or when `self` is a DataFrame and `where` is a scalar
* DataFrame : when `self` is a DataFrame and `where` is an
array-like
Return scalar, Series, or DataFrame.
See Also
--------
merge_asof : Perform an asof merge. Similar to left join.
Notes
-----
Dates are assumed to be sorted. Raises if this is not the case.
Examples
--------
A Series and a scalar `where`.
>>> s = pd.Series([1, 2, np.nan, 4], index=[10, 20, 30, 40])
>>> s
10 1.0
20 2.0
30 NaN
40 4.0
dtype: float64
>>> s.asof(20)
2.0
For a sequence `where`, a Series is returned. The first value is
NaN, because the first element of `where` is before the first
index value.
>>> s.asof([5, 20])
5 NaN
20 2.0
dtype: float64
Missing values are not considered. The following is ``2.0``, not
NaN, even though NaN is at the index location for ``30``.
>>> s.asof(30)
2.0
Take all columns into consideration
>>> df = pd.DataFrame({'a': [10, 20, 30, 40, 50],
... 'b': [None, None, None, None, 500]},
... index=pd.DatetimeIndex(['2018-02-27 09:01:00',
... '2018-02-27 09:02:00',
... '2018-02-27 09:03:00',
... '2018-02-27 09:04:00',
... '2018-02-27 09:05:00']))
>>> df.asof(pd.DatetimeIndex(['2018-02-27 09:03:30',
... '2018-02-27 09:04:30']))
a b
2018-02-27 09:03:30 NaN NaN
2018-02-27 09:04:30 NaN NaN
Take a single column into consideration
>>> df.asof(pd.DatetimeIndex(['2018-02-27 09:03:30',
... '2018-02-27 09:04:30']),
... subset=['a'])
a b
2018-02-27 09:03:30 30.0 NaN
2018-02-27 09:04:30 40.0 NaN
"""
if isinstance(where, str):
where = Timestamp(where)
if not self.index.is_monotonic:
raise ValueError("asof requires a sorted index")
is_series = isinstance(self, ABCSeries)
if is_series:
if subset is not None:
raise ValueError("subset is not valid for Series")
else:
if subset is None:
subset = self.columns
if not is_list_like(subset):
subset = [subset]
is_list = is_list_like(where)
if not is_list:
start = self.index[0]
if isinstance(self.index, PeriodIndex):
where = Period(where, freq=self.index.freq)
if where < start:
if not is_series:
from pandas import Series
return Series(index=self.columns, name=where, dtype=np.float64)
return np.nan
# It's always much faster to use a *while* loop here for
# Series than pre-computing all the NAs. However a
# *while* loop is extremely expensive for DataFrame
# so we later pre-compute all the NAs and use the same
# code path whether *where* is a scalar or list.
# See PR: https://github.com/pandas-dev/pandas/pull/14476
if is_series:
loc = self.index.searchsorted(where, side="right")
if loc > 0:
loc -= 1
values = self._values
while loc > 0 and isna(values[loc]):
loc -= 1
return values[loc]
if not isinstance(where, Index):
where = Index(where) if is_list else Index([where])
nulls = self.isna() if is_series else self[subset].isna().any(1)
if nulls.all():
if is_series:
return self._constructor(np.nan, index=where, name=self.name)
elif is_list:
from pandas import DataFrame
return DataFrame(np.nan, index=where, columns=self.columns)
else:
from pandas import Series
return Series(np.nan, index=self.columns, name=where[0])
locs = self.index.asof_locs(where, ~(nulls.values))
# mask the missing
missing = locs == -1
data = self.take(locs)
data.index = where
data.loc[missing] = np.nan
return data if is_list else data.iloc[-1]
# ----------------------------------------------------------------------
# Action Methods
_shared_docs[
"isna"
] = """
Detect missing values.
Return a boolean same-sized object indicating if the values are NA.
NA values, such as None or :attr:`numpy.NaN`, gets mapped to True
values.
Everything else gets mapped to False values. Characters such as empty
strings ``''`` or :attr:`numpy.inf` are not considered NA values
(unless you set ``pandas.options.mode.use_inf_as_na = True``).
Returns
-------
%(klass)s
Mask of bool values for each element in %(klass)s that
indicates whether an element is not an NA value.
See Also
--------
%(klass)s.isnull : Alias of isna.
%(klass)s.notna : Boolean inverse of isna.
%(klass)s.dropna : Omit axes labels with missing values.
isna : Top-level isna.
Examples
--------
Show which entries in a DataFrame are NA.
>>> df = pd.DataFrame({'age': [5, 6, np.NaN],
... 'born': [pd.NaT, pd.Timestamp('1939-05-27'),
... pd.Timestamp('1940-04-25')],
... 'name': ['Alfred', 'Batman', ''],
... 'toy': [None, 'Batmobile', 'Joker']})
>>> df
age born name toy
0 5.0 NaT Alfred None
1 6.0 1939-05-27 Batman Batmobile
2 NaN 1940-04-25 Joker
>>> df.isna()
age born name toy
0 False True False True
1 False False False False
2 True False False False
Show which entries in a Series are NA.
>>> ser = pd.Series([5, 6, np.NaN])
>>> ser
0 5.0
1 6.0
2 NaN
dtype: float64
>>> ser.isna()
0 False
1 False
2 True
dtype: bool
"""
@Appender(_shared_docs["isna"] % _shared_doc_kwargs)
def isna(self: FrameOrSeries) -> FrameOrSeries:
return isna(self).__finalize__(self)
@Appender(_shared_docs["isna"] % _shared_doc_kwargs)
def isnull(self: FrameOrSeries) -> FrameOrSeries:
return isna(self).__finalize__(self)
_shared_docs[
"notna"
] = """
Detect existing (non-missing) values.
Return a boolean same-sized object indicating if the values are not NA.
Non-missing values get mapped to True. Characters such as empty
strings ``''`` or :attr:`numpy.inf` are not considered NA values
(unless you set ``pandas.options.mode.use_inf_as_na = True``).
NA values, such as None or :attr:`numpy.NaN`, get mapped to False
values.
Returns
-------
%(klass)s
Mask of bool values for each element in %(klass)s that
indicates whether an element is not an NA value.
See Also
--------
%(klass)s.notnull : Alias of notna.
%(klass)s.isna : Boolean inverse of notna.
%(klass)s.dropna : Omit axes labels with missing values.
notna : Top-level notna.
Examples
--------
Show which entries in a DataFrame are not NA.
>>> df = pd.DataFrame({'age': [5, 6, np.NaN],
... 'born': [pd.NaT, pd.Timestamp('1939-05-27'),
... pd.Timestamp('1940-04-25')],
... 'name': ['Alfred', 'Batman', ''],
... 'toy': [None, 'Batmobile', 'Joker']})
>>> df
age born name toy
0 5.0 NaT Alfred None
1 6.0 1939-05-27 Batman Batmobile
2 NaN 1940-04-25 Joker
>>> df.notna()
age born name toy
0 True False True False
1 True True True True
2 False True True True
Show which entries in a Series are not NA.
>>> ser = pd.Series([5, 6, np.NaN])
>>> ser
0 5.0
1 6.0
2 NaN
dtype: float64
>>> ser.notna()
0 True
1 True
2 False
dtype: bool
"""
@Appender(_shared_docs["notna"] % _shared_doc_kwargs)
def notna(self: FrameOrSeries) -> FrameOrSeries:
return notna(self).__finalize__(self)
@Appender(_shared_docs["notna"] % _shared_doc_kwargs)
def notnull(self: FrameOrSeries) -> FrameOrSeries:
return notna(self).__finalize__(self)
def _clip_with_scalar(self, lower, upper, inplace: bool_t = False):
if (lower is not None and np.any(isna(lower))) or (
upper is not None and np.any(isna(upper))
):
raise ValueError("Cannot use an NA value as a clip threshold")
result = self
mask = isna(self.values)
with np.errstate(all="ignore"):
if upper is not None:
subset = self.to_numpy() <= upper
result = result.where(subset, upper, axis=None, inplace=False)
if lower is not None:
subset = self.to_numpy() >= lower
result = result.where(subset, lower, axis=None, inplace=False)
if np.any(mask):
result[mask] = np.nan
if inplace:
self._update_inplace(result)
else:
return result
def _clip_with_one_bound(self, threshold, method, axis, inplace):
if axis is not None:
axis = self._get_axis_number(axis)
# method is self.le for upper bound and self.ge for lower bound
if is_scalar(threshold) and is_number(threshold):
if method.__name__ == "le":
return self._clip_with_scalar(None, threshold, inplace=inplace)
return self._clip_with_scalar(threshold, None, inplace=inplace)
subset = method(threshold, axis=axis) | isna(self)
# GH #15390
# In order for where method to work, the threshold must
# be transformed to NDFrame from other array like structure.
if (not isinstance(threshold, ABCSeries)) and is_list_like(threshold):
if isinstance(self, ABCSeries):
threshold = self._constructor(threshold, index=self.index)
else:
threshold = _align_method_FRAME(self, threshold, axis, flex=None)[1]
return self.where(subset, threshold, axis=axis, inplace=inplace)
def clip(
self: FrameOrSeries,
lower=None,
upper=None,
axis=None,
inplace: bool_t = False,
*args,
**kwargs,
) -> FrameOrSeries:
"""
Trim values at input threshold(s).
Assigns values outside boundary to boundary values. Thresholds
can be singular values or array like, and in the latter case
the clipping is performed element-wise in the specified axis.
Parameters
----------
lower : float or array_like, default None
Minimum threshold value. All values below this
threshold will be set to it.
upper : float or array_like, default None
Maximum threshold value. All values above this
threshold will be set to it.
axis : int or str axis name, optional
Align object with lower and upper along the given axis.
inplace : bool, default False
Whether to perform the operation in place on the data.
.. versionadded:: 0.21.0
*args, **kwargs
Additional keywords have no effect but might be accepted
for compatibility with numpy.
Returns
-------
Series or DataFrame
Same type as calling object with the values outside the
clip boundaries replaced.
Examples
--------
>>> data = {'col_0': [9, -3, 0, -1, 5], 'col_1': [-2, -7, 6, 8, -5]}
>>> df = pd.DataFrame(data)
>>> df
col_0 col_1
0 9 -2
1 -3 -7
2 0 6
3 -1 8
4 5 -5
Clips per column using lower and upper thresholds:
>>> df.clip(-4, 6)
col_0 col_1
0 6 -2
1 -3 -4
2 0 6
3 -1 6
4 5 -4
Clips using specific lower and upper thresholds per column element:
>>> t = pd.Series([2, -4, -1, 6, 3])
>>> t
0 2
1 -4
2 -1
3 6
4 3
dtype: int64
>>> df.clip(t, t + 4, axis=0)
col_0 col_1
0 6 2
1 -3 -4
2 0 3
3 6 8
4 5 3
"""
inplace = validate_bool_kwarg(inplace, "inplace")
axis = nv.validate_clip_with_axis(axis, args, kwargs)
if axis is not None:
axis = self._get_axis_number(axis)
# GH 17276
# numpy doesn't like NaN as a clip value
# so ignore
# GH 19992
# numpy doesn't drop a list-like bound containing NaN
if not is_list_like(lower) and np.any(isna(lower)):
lower = None
if not is_list_like(upper) and np.any(isna(upper)):
upper = None
# GH 2747 (arguments were reversed)
if lower is not None and upper is not None:
if is_scalar(lower) and is_scalar(upper):
lower, upper = min(lower, upper), max(lower, upper)
# fast-path for scalars
if (lower is None or (is_scalar(lower) and is_number(lower))) and (
upper is None or (is_scalar(upper) and is_number(upper))
):
return self._clip_with_scalar(lower, upper, inplace=inplace)
result = self
if lower is not None:
result = result._clip_with_one_bound(
lower, method=self.ge, axis=axis, inplace=inplace
)
if upper is not None:
if inplace:
result = self
result = result._clip_with_one_bound(
upper, method=self.le, axis=axis, inplace=inplace
)
return result
_shared_docs[
"groupby"
] = """
Group %(klass)s using a mapper or by a Series of columns.
A groupby operation involves some combination of splitting the
object, applying a function, and combining the results. This can be
used to group large amounts of data and compute operations on these
groups.
Parameters
----------
by : mapping, function, label, or list of labels
Used to determine the groups for the groupby.
If ``by`` is a function, it's called on each value of the object's
index. If a dict or Series is passed, the Series or dict VALUES
will be used to determine the groups (the Series' values are first
aligned; see ``.align()`` method). If an ndarray is passed, the
values are used as-is determine the groups. A label or list of
labels may be passed to group by the columns in ``self``. Notice
that a tuple is interpreted as a (single) key.
axis : {0 or 'index', 1 or 'columns'}, default 0
Split along rows (0) or columns (1).
level : int, level name, or sequence of such, default None
If the axis is a MultiIndex (hierarchical), group by a particular
level or levels.
as_index : bool, default True
For aggregated output, return object with group labels as the
index. Only relevant for DataFrame input. as_index=False is
effectively "SQL-style" grouped output.
sort : bool, default True
Sort group keys. Get better performance by turning this off.
Note this does not influence the order of observations within each
group. Groupby preserves the order of rows within each group.
group_keys : bool, default True
When calling apply, add group keys to index to identify pieces.
squeeze : bool, default False
Reduce the dimensionality of the return type if possible,
otherwise return a consistent type.
observed : bool, default False
This only applies if any of the groupers are Categoricals.
If True: only show observed values for categorical groupers.
If False: show all values for categorical groupers.
.. versionadded:: 0.23.0
Returns
-------
%(klass)sGroupBy
Returns a groupby object that contains information about the groups.
See Also
--------
resample : Convenience method for frequency conversion and resampling
of time series.
Notes
-----
See the `user guide
<https://pandas.pydata.org/pandas-docs/stable/groupby.html>`_ for more.
"""
def asfreq(
self: FrameOrSeries,
freq,
method=None,
how: Optional[str] = None,
normalize: bool_t = False,
fill_value=None,
) -> FrameOrSeries:
"""
Convert TimeSeries to specified frequency.
Optionally provide filling method to pad/backfill missing values.
Returns the original data conformed to a new index with the specified
frequency. ``resample`` is more appropriate if an operation, such as
summarization, is necessary to represent the data at the new frequency.
Parameters
----------
freq : DateOffset or str
method : {'backfill'/'bfill', 'pad'/'ffill'}, default None
Method to use for filling holes in reindexed Series (note this
does not fill NaNs that already were present):
* 'pad' / 'ffill': propagate last valid observation forward to next
valid
* 'backfill' / 'bfill': use NEXT valid observation to fill.
how : {'start', 'end'}, default end
For PeriodIndex only (see PeriodIndex.asfreq).
normalize : bool, default False
Whether to reset output index to midnight.
fill_value : scalar, optional
Value to use for missing values, applied during upsampling (note
this does not fill NaNs that already were present).
Returns
-------
converted : same type as caller
See Also
--------
reindex
Notes
-----
To learn more about the frequency strings, please see `this link
<https://pandas.pydata.org/pandas-docs/stable/user_guide/timeseries.html#offset-aliases>`__.
Examples
--------
Start by creating a series with 4 one minute timestamps.
>>> index = pd.date_range('1/1/2000', periods=4, freq='T')
>>> series = pd.Series([0.0, None, 2.0, 3.0], index=index)
>>> df = pd.DataFrame({'s':series})
>>> df
s
2000-01-01 00:00:00 0.0
2000-01-01 00:01:00 NaN
2000-01-01 00:02:00 2.0
2000-01-01 00:03:00 3.0
Upsample the series into 30 second bins.
>>> df.asfreq(freq='30S')
s
2000-01-01 00:00:00 0.0
2000-01-01 00:00:30 NaN
2000-01-01 00:01:00 NaN
2000-01-01 00:01:30 NaN
2000-01-01 00:02:00 2.0
2000-01-01 00:02:30 NaN
2000-01-01 00:03:00 3.0
Upsample again, providing a ``fill value``.
>>> df.asfreq(freq='30S', fill_value=9.0)
s
2000-01-01 00:00:00 0.0
2000-01-01 00:00:30 9.0
2000-01-01 00:01:00 NaN
2000-01-01 00:01:30 9.0
2000-01-01 00:02:00 2.0
2000-01-01 00:02:30 9.0
2000-01-01 00:03:00 3.0
Upsample again, providing a ``method``.
>>> df.asfreq(freq='30S', method='bfill')
s
2000-01-01 00:00:00 0.0
2000-01-01 00:00:30 NaN
2000-01-01 00:01:00 NaN
2000-01-01 00:01:30 2.0
2000-01-01 00:02:00 2.0
2000-01-01 00:02:30 3.0
2000-01-01 00:03:00 3.0
"""
from pandas.core.resample import asfreq
return asfreq(
self,
freq,
method=method,
how=how,
normalize=normalize,
fill_value=fill_value,
)
def at_time(
self: FrameOrSeries, time, asof: bool_t = False, axis=None
) -> FrameOrSeries:
"""
Select values at particular time of day (e.g., 9:30AM).
Parameters
----------
time : datetime.time or str
axis : {0 or 'index', 1 or 'columns'}, default 0
.. versionadded:: 0.24.0
Returns
-------
Series or DataFrame
Raises
------
TypeError
If the index is not a :class:`DatetimeIndex`
See Also
--------
between_time : Select values between particular times of the day.
first : Select initial periods of time series based on a date offset.
last : Select final periods of time series based on a date offset.
DatetimeIndex.indexer_at_time : Get just the index locations for
values at particular time of the day.
Examples
--------
>>> i = pd.date_range('2018-04-09', periods=4, freq='12H')
>>> ts = pd.DataFrame({'A': [1, 2, 3, 4]}, index=i)
>>> ts
A
2018-04-09 00:00:00 1
2018-04-09 12:00:00 2
2018-04-10 00:00:00 3
2018-04-10 12:00:00 4
>>> ts.at_time('12:00')
A
2018-04-09 12:00:00 2
2018-04-10 12:00:00 4
"""
if axis is None:
axis = self._stat_axis_number
axis = self._get_axis_number(axis)
index = self._get_axis(axis)
try:
indexer = index.indexer_at_time(time, asof=asof)
except AttributeError:
raise TypeError("Index must be DatetimeIndex")
return self._take_with_is_copy(indexer, axis=axis)
def between_time(
self: FrameOrSeries,
start_time,
end_time,
include_start: bool_t = True,
include_end: bool_t = True,
axis=None,
) -> FrameOrSeries:
"""
Select values between particular times of the day (e.g., 9:00-9:30 AM).
By setting ``start_time`` to be later than ``end_time``,
you can get the times that are *not* between the two times.
Parameters
----------
start_time : datetime.time or str
Initial time as a time filter limit.
end_time : datetime.time or str
End time as a time filter limit.
include_start : bool, default True
Whether the start time needs to be included in the result.
include_end : bool, default True
Whether the end time needs to be included in the result.
axis : {0 or 'index', 1 or 'columns'}, default 0
Determine range time on index or columns value.
.. versionadded:: 0.24.0
Returns
-------
Series or DataFrame
Data from the original object filtered to the specified dates range.
Raises
------
TypeError
If the index is not a :class:`DatetimeIndex`
See Also
--------
at_time : Select values at a particular time of the day.
first : Select initial periods of time series based on a date offset.
last : Select final periods of time series based on a date offset.
DatetimeIndex.indexer_between_time : Get just the index locations for
values between particular times of the day.
Examples
--------
>>> i = pd.date_range('2018-04-09', periods=4, freq='1D20min')
>>> ts = pd.DataFrame({'A': [1, 2, 3, 4]}, index=i)
>>> ts
A
2018-04-09 00:00:00 1
2018-04-10 00:20:00 2
2018-04-11 00:40:00 3
2018-04-12 01:00:00 4
>>> ts.between_time('0:15', '0:45')
A
2018-04-10 00:20:00 2
2018-04-11 00:40:00 3
You get the times that are *not* between two times by setting
``start_time`` later than ``end_time``:
>>> ts.between_time('0:45', '0:15')
A
2018-04-09 00:00:00 1
2018-04-12 01:00:00 4
"""
if axis is None:
axis = self._stat_axis_number
axis = self._get_axis_number(axis)
index = self._get_axis(axis)
try:
indexer = index.indexer_between_time(
start_time,
end_time,
include_start=include_start,
include_end=include_end,
)
except AttributeError:
raise TypeError("Index must be DatetimeIndex")
return self._take_with_is_copy(indexer, axis=axis)
def resample(
self,
rule,
axis=0,
closed: Optional[str] = None,
label: Optional[str] = None,
convention: str = "start",
kind: Optional[str] = None,
loffset=None,
base: int = 0,
on=None,
level=None,
) -> "Resampler":
"""
Resample time-series data.
Convenience method for frequency conversion and resampling of time
series. Object must have a datetime-like index (`DatetimeIndex`,
`PeriodIndex`, or `TimedeltaIndex`), or pass datetime-like values
to the `on` or `level` keyword.
Parameters
----------
rule : DateOffset, Timedelta or str
The offset string or object representing target conversion.
axis : {0 or 'index', 1 or 'columns'}, default 0
Which axis to use for up- or down-sampling. For `Series` this
will default to 0, i.e. along the rows. Must be
`DatetimeIndex`, `TimedeltaIndex` or `PeriodIndex`.
closed : {'right', 'left'}, default None
Which side of bin interval is closed. The default is 'left'
for all frequency offsets except for 'M', 'A', 'Q', 'BM',
'BA', 'BQ', and 'W' which all have a default of 'right'.
label : {'right', 'left'}, default None
Which bin edge label to label bucket with. The default is 'left'
for all frequency offsets except for 'M', 'A', 'Q', 'BM',
'BA', 'BQ', and 'W' which all have a default of 'right'.
convention : {'start', 'end', 's', 'e'}, default 'start'
For `PeriodIndex` only, controls whether to use the start or
end of `rule`.
kind : {'timestamp', 'period'}, optional, default None
Pass 'timestamp' to convert the resulting index to a
`DateTimeIndex` or 'period' to convert it to a `PeriodIndex`.
By default the input representation is retained.
loffset : timedelta, default None
Adjust the resampled time labels.
base : int, default 0
For frequencies that evenly subdivide 1 day, the "origin" of the
aggregated intervals. For example, for '5min' frequency, base could
range from 0 through 4. Defaults to 0.
on : str, optional
For a DataFrame, column to use instead of index for resampling.
Column must be datetime-like.
level : str or int, optional
For a MultiIndex, level (name or number) to use for
resampling. `level` must be datetime-like.
Returns
-------
Resampler object
See Also
--------
groupby : Group by mapping, function, label, or list of labels.
Series.resample : Resample a Series.
DataFrame.resample: Resample a DataFrame.
Notes
-----
See the `user guide
<https://pandas.pydata.org/pandas-docs/stable/user_guide/timeseries.html#resampling>`_
for more.
To learn more about the offset strings, please see `this link
<https://pandas.pydata.org/pandas-docs/stable/user_guide/timeseries.html#dateoffset-objects>`__.
Examples
--------
Start by creating a series with 9 one minute timestamps.
>>> index = pd.date_range('1/1/2000', periods=9, freq='T')
>>> series = pd.Series(range(9), index=index)
>>> series
2000-01-01 00:00:00 0
2000-01-01 00:01:00 1
2000-01-01 00:02:00 2
2000-01-01 00:03:00 3
2000-01-01 00:04:00 4
2000-01-01 00:05:00 5
2000-01-01 00:06:00 6
2000-01-01 00:07:00 7
2000-01-01 00:08:00 8
Freq: T, dtype: int64
Downsample the series into 3 minute bins and sum the values
of the timestamps falling into a bin.
>>> series.resample('3T').sum()
2000-01-01 00:00:00 3
2000-01-01 00:03:00 12
2000-01-01 00:06:00 21
Freq: 3T, dtype: int64
Downsample the series into 3 minute bins as above, but label each
bin using the right edge instead of the left. Please note that the
value in the bucket used as the label is not included in the bucket,
which it labels. For example, in the original series the
bucket ``2000-01-01 00:03:00`` contains the value 3, but the summed
value in the resampled bucket with the label ``2000-01-01 00:03:00``
does not include 3 (if it did, the summed value would be 6, not 3).
To include this value close the right side of the bin interval as
illustrated in the example below this one.
>>> series.resample('3T', label='right').sum()
2000-01-01 00:03:00 3
2000-01-01 00:06:00 12
2000-01-01 00:09:00 21
Freq: 3T, dtype: int64
Downsample the series into 3 minute bins as above, but close the right
side of the bin interval.
>>> series.resample('3T', label='right', closed='right').sum()
2000-01-01 00:00:00 0
2000-01-01 00:03:00 6
2000-01-01 00:06:00 15
2000-01-01 00:09:00 15
Freq: 3T, dtype: int64
Upsample the series into 30 second bins.
>>> series.resample('30S').asfreq()[0:5] # Select first 5 rows
2000-01-01 00:00:00 0.0
2000-01-01 00:00:30 NaN
2000-01-01 00:01:00 1.0
2000-01-01 00:01:30 NaN
2000-01-01 00:02:00 2.0
Freq: 30S, dtype: float64
Upsample the series into 30 second bins and fill the ``NaN``
values using the ``pad`` method.
>>> series.resample('30S').pad()[0:5]
2000-01-01 00:00:00 0
2000-01-01 00:00:30 0
2000-01-01 00:01:00 1
2000-01-01 00:01:30 1
2000-01-01 00:02:00 2
Freq: 30S, dtype: int64
Upsample the series into 30 second bins and fill the
``NaN`` values using the ``bfill`` method.
>>> series.resample('30S').bfill()[0:5]
2000-01-01 00:00:00 0
2000-01-01 00:00:30 1
2000-01-01 00:01:00 1
2000-01-01 00:01:30 2
2000-01-01 00:02:00 2
Freq: 30S, dtype: int64
Pass a custom function via ``apply``
>>> def custom_resampler(array_like):
... return np.sum(array_like) + 5
...
>>> series.resample('3T').apply(custom_resampler)
2000-01-01 00:00:00 8
2000-01-01 00:03:00 17
2000-01-01 00:06:00 26
Freq: 3T, dtype: int64
For a Series with a PeriodIndex, the keyword `convention` can be
used to control whether to use the start or end of `rule`.
Resample a year by quarter using 'start' `convention`. Values are
assigned to the first quarter of the period.
>>> s = pd.Series([1, 2], index=pd.period_range('2012-01-01',
... freq='A',
... periods=2))
>>> s
2012 1
2013 2
Freq: A-DEC, dtype: int64
>>> s.resample('Q', convention='start').asfreq()
2012Q1 1.0
2012Q2 NaN
2012Q3 NaN
2012Q4 NaN
2013Q1 2.0
2013Q2 NaN
2013Q3 NaN
2013Q4 NaN
Freq: Q-DEC, dtype: float64
Resample quarters by month using 'end' `convention`. Values are
assigned to the last month of the period.
>>> q = pd.Series([1, 2, 3, 4], index=pd.period_range('2018-01-01',
... freq='Q',
... periods=4))
>>> q
2018Q1 1
2018Q2 2
2018Q3 3
2018Q4 4
Freq: Q-DEC, dtype: int64
>>> q.resample('M', convention='end').asfreq()
2018-03 1.0
2018-04 NaN
2018-05 NaN
2018-06 2.0
2018-07 NaN
2018-08 NaN
2018-09 3.0
2018-10 NaN
2018-11 NaN
2018-12 4.0
Freq: M, dtype: float64
For DataFrame objects, the keyword `on` can be used to specify the
column instead of the index for resampling.
>>> d = dict({'price': [10, 11, 9, 13, 14, 18, 17, 19],
... 'volume': [50, 60, 40, 100, 50, 100, 40, 50]})
>>> df = pd.DataFrame(d)
>>> df['week_starting'] = pd.date_range('01/01/2018',
... periods=8,
... freq='W')
>>> df
price volume week_starting
0 10 50 2018-01-07
1 11 60 2018-01-14
2 9 40 2018-01-21
3 13 100 2018-01-28
4 14 50 2018-02-04
5 18 100 2018-02-11
6 17 40 2018-02-18
7 19 50 2018-02-25
>>> df.resample('M', on='week_starting').mean()
price volume
week_starting
2018-01-31 10.75 62.5
2018-02-28 17.00 60.0
For a DataFrame with MultiIndex, the keyword `level` can be used to
specify on which level the resampling needs to take place.
>>> days = pd.date_range('1/1/2000', periods=4, freq='D')
>>> d2 = dict({'price': [10, 11, 9, 13, 14, 18, 17, 19],
... 'volume': [50, 60, 40, 100, 50, 100, 40, 50]})
>>> df2 = pd.DataFrame(d2,
... index=pd.MultiIndex.from_product([days,
... ['morning',
... 'afternoon']]
... ))
>>> df2
price volume
2000-01-01 morning 10 50
afternoon 11 60
2000-01-02 morning 9 40
afternoon 13 100
2000-01-03 morning 14 50
afternoon 18 100
2000-01-04 morning 17 40
afternoon 19 50
>>> df2.resample('D', level=0).sum()
price volume
2000-01-01 21 110
2000-01-02 22 140
2000-01-03 32 150
2000-01-04 36 90
"""
from pandas.core.resample import get_resampler
axis = self._get_axis_number(axis)
return get_resampler(
self,
freq=rule,
label=label,
closed=closed,
axis=axis,
kind=kind,
loffset=loffset,
convention=convention,
base=base,
key=on,
level=level,
)
def first(self: FrameOrSeries, offset) -> FrameOrSeries:
"""
Method to subset initial periods of time series data based on a date offset.
Parameters
----------
offset : str, DateOffset, dateutil.relativedelta
Returns
-------
subset : same type as caller
Raises
------
TypeError
If the index is not a :class:`DatetimeIndex`
See Also
--------
last : Select final periods of time series based on a date offset.
at_time : Select values at a particular time of the day.
between_time : Select values between particular times of the day.
Examples
--------
>>> i = pd.date_range('2018-04-09', periods=4, freq='2D')
>>> ts = pd.DataFrame({'A': [1,2,3,4]}, index=i)
>>> ts
A
2018-04-09 1
2018-04-11 2
2018-04-13 3
2018-04-15 4
Get the rows for the first 3 days:
>>> ts.first('3D')
A
2018-04-09 1
2018-04-11 2
Notice the data for 3 first calender days were returned, not the first
3 days observed in the dataset, and therefore data for 2018-04-13 was
not returned.
"""
if not isinstance(self.index, DatetimeIndex):
raise TypeError("'first' only supports a DatetimeIndex index")
if len(self.index) == 0:
return self
offset = to_offset(offset)
end_date = end = self.index[0] + offset
# Tick-like, e.g. 3 weeks
if not offset.is_anchored() and hasattr(offset, "_inc"):
if end_date in self.index:
end = self.index.searchsorted(end_date, side="left")
return self.iloc[:end]
return self.loc[:end]
def last(self: FrameOrSeries, offset) -> FrameOrSeries:
"""
Method to subset final periods of time series data based on a date offset.
Parameters
----------
offset : str, DateOffset, dateutil.relativedelta
Returns
-------
subset : same type as caller
Raises
------
TypeError
If the index is not a :class:`DatetimeIndex`
See Also
--------
first : Select initial periods of time series based on a date offset.
at_time : Select values at a particular time of the day.
between_time : Select values between particular times of the day.
Examples
--------
>>> i = pd.date_range('2018-04-09', periods=4, freq='2D')
>>> ts = pd.DataFrame({'A': [1, 2, 3, 4]}, index=i)
>>> ts
A
2018-04-09 1
2018-04-11 2
2018-04-13 3
2018-04-15 4
Get the rows for the last 3 days:
>>> ts.last('3D')
A
2018-04-13 3
2018-04-15 4
Notice the data for 3 last calender days were returned, not the last
3 observed days in the dataset, and therefore data for 2018-04-11 was
not returned.
"""
if not isinstance(self.index, DatetimeIndex):
raise TypeError("'last' only supports a DatetimeIndex index")
if len(self.index) == 0:
return self
offset = to_offset(offset)
start_date = self.index[-1] - offset
start = self.index.searchsorted(start_date, side="right")
return self.iloc[start:]
def rank(
self: FrameOrSeries,
axis=0,
method: str = "average",
numeric_only: Optional[bool_t] = None,
na_option: str = "keep",
ascending: bool_t = True,
pct: bool_t = False,
) -> FrameOrSeries:
"""
Compute numerical data ranks (1 through n) along axis.
By default, equal values are assigned a rank that is the average of the
ranks of those values.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
Index to direct ranking.
method : {'average', 'min', 'max', 'first', 'dense'}, default 'average'
How to rank the group of records that have the same value (i.e. ties):
* average: average rank of the group
* min: lowest rank in the group
* max: highest rank in the group
* first: ranks assigned in order they appear in the array
* dense: like 'min', but rank always increases by 1 between groups.
numeric_only : bool, optional
For DataFrame objects, rank only numeric columns if set to True.
na_option : {'keep', 'top', 'bottom'}, default 'keep'
How to rank NaN values:
* keep: assign NaN rank to NaN values
* top: assign smallest rank to NaN values if ascending
* bottom: assign highest rank to NaN values if ascending.
ascending : bool, default True
Whether or not the elements should be ranked in ascending order.
pct : bool, default False
Whether or not to display the returned rankings in percentile
form.
Returns
-------
same type as caller
Return a Series or DataFrame with data ranks as values.
See Also
--------
core.groupby.GroupBy.rank : Rank of values within each group.
Examples
--------
>>> df = pd.DataFrame(data={'Animal': ['cat', 'penguin', 'dog',
... 'spider', 'snake'],
... 'Number_legs': [4, 2, 4, 8, np.nan]})
>>> df
Animal Number_legs
0 cat 4.0
1 penguin 2.0
2 dog 4.0
3 spider 8.0
4 snake NaN
The following example shows how the method behaves with the above
parameters:
* default_rank: this is the default behaviour obtained without using
any parameter.
* max_rank: setting ``method = 'max'`` the records that have the
same values are ranked using the highest rank (e.g.: since 'cat'
and 'dog' are both in the 2nd and 3rd position, rank 3 is assigned.)
* NA_bottom: choosing ``na_option = 'bottom'``, if there are records
with NaN values they are placed at the bottom of the ranking.
* pct_rank: when setting ``pct = True``, the ranking is expressed as
percentile rank.
>>> df['default_rank'] = df['Number_legs'].rank()
>>> df['max_rank'] = df['Number_legs'].rank(method='max')
>>> df['NA_bottom'] = df['Number_legs'].rank(na_option='bottom')
>>> df['pct_rank'] = df['Number_legs'].rank(pct=True)
>>> df
Animal Number_legs default_rank max_rank NA_bottom pct_rank
0 cat 4.0 2.5 3.0 2.5 0.625
1 penguin 2.0 1.0 1.0 1.0 0.250
2 dog 4.0 2.5 3.0 2.5 0.625
3 spider 8.0 4.0 4.0 4.0 1.000
4 snake NaN NaN NaN 5.0 NaN
"""
axis = self._get_axis_number(axis)
if na_option not in {"keep", "top", "bottom"}:
msg = "na_option must be one of 'keep', 'top', or 'bottom'"
raise ValueError(msg)
def ranker(data):
ranks = algos.rank(
data.values,
axis=axis,
method=method,
ascending=ascending,
na_option=na_option,
pct=pct,
)
ranks = self._constructor(ranks, **data._construct_axes_dict())
return ranks.__finalize__(self)
# if numeric_only is None, and we can't get anything, we try with
# numeric_only=True
if numeric_only is None:
try:
return ranker(self)
except TypeError:
numeric_only = True
if numeric_only:
data = self._get_numeric_data()
else:
data = self
return ranker(data)
_shared_docs[
"align"
] = """
Align two objects on their axes with the specified join method.
Join method is specified for each axis Index.
Parameters
----------
other : DataFrame or Series
join : {'outer', 'inner', 'left', 'right'}, default 'outer'
axis : allowed axis of the other object, default None
Align on index (0), columns (1), or both (None).
level : int or level name, default None
Broadcast across a level, matching Index values on the
passed MultiIndex level.
copy : bool, default True
Always returns new objects. If copy=False and no reindexing is
required then original objects are returned.
fill_value : scalar, default np.NaN
Value to use for missing values. Defaults to NaN, but can be any
"compatible" value.
method : {'backfill', 'bfill', 'pad', 'ffill', None}, default None
Method to use for filling holes in reindexed Series:
- pad / ffill: propagate last valid observation forward to next valid.
- backfill / bfill: use NEXT valid observation to fill gap.
limit : int, default None
If method is specified, this is the maximum number of consecutive
NaN values to forward/backward fill. In other words, if there is
a gap with more than this number of consecutive NaNs, it will only
be partially filled. If method is not specified, this is the
maximum number of entries along the entire axis where NaNs will be
filled. Must be greater than 0 if not None.
fill_axis : %(axes_single_arg)s, default 0
Filling axis, method and limit.
broadcast_axis : %(axes_single_arg)s, default None
Broadcast values along this axis, if aligning two objects of
different dimensions.
Returns
-------
(left, right) : (%(klass)s, type of other)
Aligned objects.
"""
@Appender(_shared_docs["align"] % _shared_doc_kwargs)
def align(
self,
other,
join="outer",
axis=None,
level=None,
copy=True,
fill_value=None,
method=None,
limit=None,
fill_axis=0,
broadcast_axis=None,
):
method = missing.clean_fill_method(method)
if broadcast_axis == 1 and self.ndim != other.ndim:
if isinstance(self, ABCSeries):
# this means other is a DataFrame, and we need to broadcast
# self
cons = self._constructor_expanddim
df = cons(
{c: self for c in other.columns}, **other._construct_axes_dict()
)
return df._align_frame(
other,
join=join,
axis=axis,
level=level,
copy=copy,
fill_value=fill_value,
method=method,
limit=limit,
fill_axis=fill_axis,
)
elif isinstance(other, ABCSeries):
# this means self is a DataFrame, and we need to broadcast
# other
cons = other._constructor_expanddim
df = cons(
{c: other for c in self.columns}, **self._construct_axes_dict()
)
return self._align_frame(
df,
join=join,
axis=axis,
level=level,
copy=copy,
fill_value=fill_value,
method=method,
limit=limit,
fill_axis=fill_axis,
)
if axis is not None:
axis = self._get_axis_number(axis)
if isinstance(other, ABCDataFrame):
return self._align_frame(
other,
join=join,
axis=axis,
level=level,
copy=copy,
fill_value=fill_value,
method=method,
limit=limit,
fill_axis=fill_axis,
)
elif isinstance(other, ABCSeries):
return self._align_series(
other,
join=join,
axis=axis,
level=level,
copy=copy,
fill_value=fill_value,
method=method,
limit=limit,
fill_axis=fill_axis,
)
else: # pragma: no cover
raise TypeError(f"unsupported type: {type(other)}")
def _align_frame(
self,
other,
join="outer",
axis=None,
level=None,
copy: bool_t = True,
fill_value=None,
method=None,
limit=None,
fill_axis=0,
):
# defaults
join_index, join_columns = None, None
ilidx, iridx = None, None
clidx, cridx = None, None
is_series = isinstance(self, ABCSeries)
if axis is None or axis == 0:
if not self.index.equals(other.index):
join_index, ilidx, iridx = self.index.join(
other.index, how=join, level=level, return_indexers=True
)
if axis is None or axis == 1:
if not is_series and not self.columns.equals(other.columns):
join_columns, clidx, cridx = self.columns.join(
other.columns, how=join, level=level, return_indexers=True
)
if is_series:
reindexers = {0: [join_index, ilidx]}
else:
reindexers = {0: [join_index, ilidx], 1: [join_columns, clidx]}
left = self._reindex_with_indexers(
reindexers, copy=copy, fill_value=fill_value, allow_dups=True
)
# other must be always DataFrame
right = other._reindex_with_indexers(
{0: [join_index, iridx], 1: [join_columns, cridx]},
copy=copy,
fill_value=fill_value,
allow_dups=True,
)
if method is not None:
left = self._ensure_type(
left.fillna(method=method, axis=fill_axis, limit=limit)
)
right = right.fillna(method=method, axis=fill_axis, limit=limit)
# if DatetimeIndex have different tz, convert to UTC
if is_datetime64tz_dtype(left.index):
if left.index.tz != right.index.tz:
if join_index is not None:
left.index = join_index
right.index = join_index
return left.__finalize__(self), right.__finalize__(other)
def _align_series(
self,
other,
join="outer",
axis=None,
level=None,
copy: bool_t = True,
fill_value=None,
method=None,
limit=None,
fill_axis=0,
):
is_series = isinstance(self, ABCSeries)
# series/series compat, other must always be a Series
if is_series:
if axis:
raise ValueError("cannot align series to a series other than axis 0")
# equal
if self.index.equals(other.index):
join_index, lidx, ridx = None, None, None
else:
join_index, lidx, ridx = self.index.join(
other.index, how=join, level=level, return_indexers=True
)
left = self._reindex_indexer(join_index, lidx, copy)
right = other._reindex_indexer(join_index, ridx, copy)
else:
# one has > 1 ndim
fdata = self._data
if axis == 0:
join_index = self.index
lidx, ridx = None, None
if not self.index.equals(other.index):
join_index, lidx, ridx = self.index.join(
other.index, how=join, level=level, return_indexers=True
)
if lidx is not None:
fdata = fdata.reindex_indexer(join_index, lidx, axis=1)
elif axis == 1:
join_index = self.columns
lidx, ridx = None, None
if not self.columns.equals(other.index):
join_index, lidx, ridx = self.columns.join(
other.index, how=join, level=level, return_indexers=True
)
if lidx is not None:
fdata = fdata.reindex_indexer(join_index, lidx, axis=0)
else:
raise ValueError("Must specify axis=0 or 1")
if copy and fdata is self._data:
fdata = fdata.copy()
left = self._constructor(fdata)
if ridx is None:
right = other
else:
right = other.reindex(join_index, level=level)
# fill
fill_na = notna(fill_value) or (method is not None)
if fill_na:
left = left.fillna(fill_value, method=method, limit=limit, axis=fill_axis)
right = right.fillna(fill_value, method=method, limit=limit)
# if DatetimeIndex have different tz, convert to UTC
if is_series or (not is_series and axis == 0):
if is_datetime64tz_dtype(left.index):
if left.index.tz != right.index.tz:
if join_index is not None:
left.index = join_index
right.index = join_index
return left.__finalize__(self), right.__finalize__(other)
def _where(
self,
cond,
other=np.nan,
inplace=False,
axis=None,
level=None,
errors="raise",
try_cast=False,
):
"""
Equivalent to public method `where`, except that `other` is not
applied as a function even if callable. Used in __setitem__.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
# align the cond to same shape as myself
cond = com.apply_if_callable(cond, self)
if isinstance(cond, NDFrame):
cond, _ = cond.align(self, join="right", broadcast_axis=1)
else:
if not hasattr(cond, "shape"):
cond = np.asanyarray(cond)
if cond.shape != self.shape:
raise ValueError("Array conditional must be same shape as self")
cond = self._constructor(cond, **self._construct_axes_dict())
# make sure we are boolean
fill_value = bool(inplace)
cond = cond.fillna(fill_value)
msg = "Boolean array expected for the condition, not {dtype}"
if not isinstance(cond, ABCDataFrame):
# This is a single-dimensional object.
if not is_bool_dtype(cond):
raise ValueError(msg.format(dtype=cond.dtype))
elif not cond.empty:
for dt in cond.dtypes:
if not is_bool_dtype(dt):
raise ValueError(msg.format(dtype=dt))
cond = -cond if inplace else cond
# try to align with other
try_quick = True
if hasattr(other, "align"):
# align with me
if other.ndim <= self.ndim:
_, other = self.align(
other, join="left", axis=axis, level=level, fill_value=np.nan
)
# if we are NOT aligned, raise as we cannot where index
if axis is None and not all(
other._get_axis(i).equals(ax) for i, ax in enumerate(self.axes)
):
raise InvalidIndexError
# slice me out of the other
else:
raise NotImplementedError(
"cannot align with a higher dimensional NDFrame"
)
if isinstance(other, np.ndarray):
if other.shape != self.shape:
if self.ndim == 1:
icond = cond.values
# GH 2745 / GH 4192
# treat like a scalar
if len(other) == 1:
other = np.array(other[0])
# GH 3235
# match True cond to other
elif len(cond[icond]) == len(other):
# try to not change dtype at first (if try_quick)
if try_quick:
new_other = com.values_from_object(self)
new_other = new_other.copy()
new_other[icond] = other
other = new_other
else:
raise ValueError(
"Length of replacements must equal series length"
)
else:
raise ValueError(
"other must be the same shape as self when an ndarray"
)
# we are the same shape, so create an actual object for alignment
else:
other = self._constructor(other, **self._construct_axes_dict())
if axis is None:
axis = 0
if self.ndim == getattr(other, "ndim", 0):
align = True
else:
align = self._get_axis_number(axis) == 1
block_axis = self._get_block_manager_axis(axis)
if inplace:
# we may have different type blocks come out of putmask, so
# reconstruct the block manager
self._check_inplace_setting(other)
new_data = self._data.putmask(
mask=cond,
new=other,
align=align,
inplace=True,
axis=block_axis,
transpose=self._AXIS_REVERSED,
)
self._update_inplace(new_data)
else:
new_data = self._data.where(
other=other,
cond=cond,
align=align,
errors=errors,
try_cast=try_cast,
axis=block_axis,
)
return self._constructor(new_data).__finalize__(self)
_shared_docs[
"where"
] = """
Replace values where the condition is %(cond_rev)s.
Parameters
----------
cond : bool %(klass)s, array-like, or callable
Where `cond` is %(cond)s, keep the original value. Where
%(cond_rev)s, replace with corresponding value from `other`.
If `cond` is callable, it is computed on the %(klass)s and
should return boolean %(klass)s or array. The callable must
not change input %(klass)s (though pandas doesn't check it).
other : scalar, %(klass)s, or callable
Entries where `cond` is %(cond_rev)s are replaced with
corresponding value from `other`.
If other is callable, it is computed on the %(klass)s and
should return scalar or %(klass)s. The callable must not
change input %(klass)s (though pandas doesn't check it).
inplace : bool, default False
Whether to perform the operation in place on the data.
axis : int, default None
Alignment axis if needed.
level : int, default None
Alignment level if needed.
errors : str, {'raise', 'ignore'}, default 'raise'
Note that currently this parameter won't affect
the results and will always coerce to a suitable dtype.
- 'raise' : allow exceptions to be raised.
- 'ignore' : suppress exceptions. On error return original object.
try_cast : bool, default False
Try to cast the result back to the input type (if possible).
Returns
-------
Same type as caller
See Also
--------
:func:`DataFrame.%(name_other)s` : Return an object of same shape as
self.
Notes
-----
The %(name)s method is an application of the if-then idiom. For each
element in the calling DataFrame, if ``cond`` is ``%(cond)s`` the
element is used; otherwise the corresponding element from the DataFrame
``other`` is used.
The signature for :func:`DataFrame.where` differs from
:func:`numpy.where`. Roughly ``df1.where(m, df2)`` is equivalent to
``np.where(m, df1, df2)``.
For further details and examples see the ``%(name)s`` documentation in
:ref:`indexing <indexing.where_mask>`.
Examples
--------
>>> s = pd.Series(range(5))
>>> s.where(s > 0)
0 NaN
1 1.0
2 2.0
3 3.0
4 4.0
dtype: float64
>>> s.mask(s > 0)
0 0.0
1 NaN
2 NaN
3 NaN
4 NaN
dtype: float64
>>> s.where(s > 1, 10)
0 10
1 10
2 2
3 3
4 4
dtype: int64
>>> df = pd.DataFrame(np.arange(10).reshape(-1, 2), columns=['A', 'B'])
>>> df
A B
0 0 1
1 2 3
2 4 5
3 6 7
4 8 9
>>> m = df %% 3 == 0
>>> df.where(m, -df)
A B
0 0 -1
1 -2 3
2 -4 -5
3 6 -7
4 -8 9
>>> df.where(m, -df) == np.where(m, df, -df)
A B
0 True True
1 True True
2 True True
3 True True
4 True True
>>> df.where(m, -df) == df.mask(~m, -df)
A B
0 True True
1 True True
2 True True
3 True True
4 True True
"""
@Appender(
_shared_docs["where"]
% dict(
_shared_doc_kwargs,
cond="True",
cond_rev="False",
name="where",
name_other="mask",
)
)
def where(
self,
cond,
other=np.nan,
inplace=False,
axis=None,
level=None,
errors="raise",
try_cast=False,
):
other = com.apply_if_callable(other, self)
return self._where(
cond, other, inplace, axis, level, errors=errors, try_cast=try_cast
)
@Appender(
_shared_docs["where"]
% dict(
_shared_doc_kwargs,
cond="False",
cond_rev="True",
name="mask",
name_other="where",
)
)
def mask(
self,
cond,
other=np.nan,
inplace=False,
axis=None,
level=None,
errors="raise",
try_cast=False,
):
inplace = validate_bool_kwarg(inplace, "inplace")
cond = com.apply_if_callable(cond, self)
# see gh-21891
if not hasattr(cond, "__invert__"):
cond = np.array(cond)
return self.where(
~cond,
other=other,
inplace=inplace,
axis=axis,
level=level,
try_cast=try_cast,
errors=errors,
)
_shared_docs[
"shift"
] = """
Shift index by desired number of periods with an optional time `freq`.
When `freq` is not passed, shift the index without realigning the data.
If `freq` is passed (in this case, the index must be date or datetime,
or it will raise a `NotImplementedError`), the index will be
increased using the periods and the `freq`.
Parameters
----------
periods : int
Number of periods to shift. Can be positive or negative.
freq : DateOffset, tseries.offsets, timedelta, or str, optional
Offset to use from the tseries module or time rule (e.g. 'EOM').
If `freq` is specified then the index values are shifted but the
data is not realigned. That is, use `freq` if you would like to
extend the index when shifting and preserve the original data.
axis : {0 or 'index', 1 or 'columns', None}, default None
Shift direction.
fill_value : object, optional
The scalar value to use for newly introduced missing values.
the default depends on the dtype of `self`.
For numeric data, ``np.nan`` is used.
For datetime, timedelta, or period data, etc. :attr:`NaT` is used.
For extension dtypes, ``self.dtype.na_value`` is used.
.. versionchanged:: 0.24.0
Returns
-------
%(klass)s
Copy of input object, shifted.
See Also
--------
Index.shift : Shift values of Index.
DatetimeIndex.shift : Shift values of DatetimeIndex.
PeriodIndex.shift : Shift values of PeriodIndex.
tshift : Shift the time index, using the index's frequency if
available.
Examples
--------
>>> df = pd.DataFrame({'Col1': [10, 20, 15, 30, 45],
... 'Col2': [13, 23, 18, 33, 48],
... 'Col3': [17, 27, 22, 37, 52]})
>>> df.shift(periods=3)
Col1 Col2 Col3
0 NaN NaN NaN
1 NaN NaN NaN
2 NaN NaN NaN
3 10.0 13.0 17.0
4 20.0 23.0 27.0
>>> df.shift(periods=1, axis='columns')
Col1 Col2 Col3
0 NaN 10.0 13.0
1 NaN 20.0 23.0
2 NaN 15.0 18.0
3 NaN 30.0 33.0
4 NaN 45.0 48.0
>>> df.shift(periods=3, fill_value=0)
Col1 Col2 Col3
0 0 0 0
1 0 0 0
2 0 0 0
3 10 13 17
4 20 23 27
"""
@Appender(_shared_docs["shift"] % _shared_doc_kwargs)
def shift(
self: FrameOrSeries, periods=1, freq=None, axis=0, fill_value=None
) -> FrameOrSeries:
if periods == 0:
return self.copy()
block_axis = self._get_block_manager_axis(axis)
if freq is None:
new_data = self._data.shift(
periods=periods, axis=block_axis, fill_value=fill_value
)
else:
return self.tshift(periods, freq)
return self._constructor(new_data).__finalize__(self)
def slice_shift(self: FrameOrSeries, periods: int = 1, axis=0) -> FrameOrSeries:
"""
Equivalent to `shift` without copying data.
The shifted data will not include the dropped periods and the
shifted axis will be smaller than the original.
Parameters
----------
periods : int
Number of periods to move, can be positive or negative.
Returns
-------
shifted : same type as caller
Notes
-----
While the `slice_shift` is faster than `shift`, you may pay for it
later during alignment.
"""
if periods == 0:
return self
if periods > 0:
vslicer = slice(None, -periods)
islicer = slice(periods, None)
else:
vslicer = slice(-periods, None)
islicer = slice(None, periods)
new_obj = self._slice(vslicer, axis=axis)
shifted_axis = self._get_axis(axis)[islicer]
new_obj.set_axis(shifted_axis, axis=axis, inplace=True)
return new_obj.__finalize__(self)
def tshift(
self: FrameOrSeries, periods: int = 1, freq=None, axis=0
) -> FrameOrSeries:
"""
Shift the time index, using the index's frequency if available.
Parameters
----------
periods : int
Number of periods to move, can be positive or negative.
freq : DateOffset, timedelta, or str, default None
Increment to use from the tseries module
or time rule expressed as a string (e.g. 'EOM').
axis : {0 or ‘index’, 1 or ‘columns’, None}, default 0
Corresponds to the axis that contains the Index.
Returns
-------
shifted : Series/DataFrame
Notes
-----
If freq is not specified then tries to use the freq or inferred_freq
attributes of the index. If neither of those attributes exist, a
ValueError is thrown
"""
index = self._get_axis(axis)
if freq is None:
freq = getattr(index, "freq", None)
if freq is None:
freq = getattr(index, "inferred_freq", None)
if freq is None:
msg = "Freq was not given and was not set in the index"
raise ValueError(msg)
if periods == 0:
return self
if isinstance(freq, str):
freq = to_offset(freq)
block_axis = self._get_block_manager_axis(axis)
if isinstance(index, PeriodIndex):
orig_freq = to_offset(index.freq)
if freq == orig_freq:
new_data = self._data.copy()
new_data.axes[block_axis] = index.shift(periods)
elif orig_freq is not None:
raise ValueError(
f"Given freq {freq.rule_code} does not match "
f"PeriodIndex freq {orig_freq.rule_code}"
)
else:
new_data = self._data.copy()
new_data.axes[block_axis] = index.shift(periods, freq)
return self._constructor(new_data).__finalize__(self)
def truncate(
self: FrameOrSeries, before=None, after=None, axis=None, copy: bool_t = True
) -> FrameOrSeries:
"""
Truncate a Series or DataFrame before and after some index value.
This is a useful shorthand for boolean indexing based on index
values above or below certain thresholds.
Parameters
----------
before : date, str, int
Truncate all rows before this index value.
after : date, str, int
Truncate all rows after this index value.
axis : {0 or 'index', 1 or 'columns'}, optional
Axis to truncate. Truncates the index (rows) by default.
copy : bool, default is True,
Return a copy of the truncated section.
Returns
-------
type of caller
The truncated Series or DataFrame.
See Also
--------
DataFrame.loc : Select a subset of a DataFrame by label.
DataFrame.iloc : Select a subset of a DataFrame by position.
Notes
-----
If the index being truncated contains only datetime values,
`before` and `after` may be specified as strings instead of
Timestamps.
Examples
--------
>>> df = pd.DataFrame({'A': ['a', 'b', 'c', 'd', 'e'],
... 'B': ['f', 'g', 'h', 'i', 'j'],
... 'C': ['k', 'l', 'm', 'n', 'o']},
... index=[1, 2, 3, 4, 5])
>>> df
A B C
1 a f k
2 b g l
3 c h m
4 d i n
5 e j o
>>> df.truncate(before=2, after=4)
A B C
2 b g l
3 c h m
4 d i n
The columns of a DataFrame can be truncated.
>>> df.truncate(before="A", after="B", axis="columns")
A B
1 a f
2 b g
3 c h
4 d i
5 e j
For Series, only rows can be truncated.
>>> df['A'].truncate(before=2, after=4)
2 b
3 c
4 d
Name: A, dtype: object
The index values in ``truncate`` can be datetimes or string
dates.
>>> dates = pd.date_range('2016-01-01', '2016-02-01', freq='s')
>>> df = pd.DataFrame(index=dates, data={'A': 1})
>>> df.tail()
A
2016-01-31 23:59:56 1
2016-01-31 23:59:57 1
2016-01-31 23:59:58 1
2016-01-31 23:59:59 1
2016-02-01 00:00:00 1
>>> df.truncate(before=pd.Timestamp('2016-01-05'),
... after=pd.Timestamp('2016-01-10')).tail()
A
2016-01-09 23:59:56 1
2016-01-09 23:59:57 1
2016-01-09 23:59:58 1
2016-01-09 23:59:59 1
2016-01-10 00:00:00 1
Because the index is a DatetimeIndex containing only dates, we can
specify `before` and `after` as strings. They will be coerced to
Timestamps before truncation.
>>> df.truncate('2016-01-05', '2016-01-10').tail()
A
2016-01-09 23:59:56 1
2016-01-09 23:59:57 1
2016-01-09 23:59:58 1
2016-01-09 23:59:59 1
2016-01-10 00:00:00 1
Note that ``truncate`` assumes a 0 value for any unspecified time
component (midnight). This differs from partial string slicing, which
returns any partially matching dates.
>>> df.loc['2016-01-05':'2016-01-10', :].tail()
A
2016-01-10 23:59:55 1
2016-01-10 23:59:56 1
2016-01-10 23:59:57 1
2016-01-10 23:59:58 1
2016-01-10 23:59:59 1
"""
if axis is None:
axis = self._stat_axis_number
axis = self._get_axis_number(axis)
ax = self._get_axis(axis)
# GH 17935
# Check that index is sorted
if not ax.is_monotonic_increasing and not ax.is_monotonic_decreasing:
raise ValueError("truncate requires a sorted index")
# if we have a date index, convert to dates, otherwise
# treat like a slice
if ax.is_all_dates:
from pandas.core.tools.datetimes import to_datetime
before = to_datetime(before)
after = to_datetime(after)
if before is not None and after is not None:
if before > after:
raise ValueError(f"Truncate: {after} must be after {before}")
slicer = [slice(None, None)] * self._AXIS_LEN
slicer[axis] = slice(before, after)
result = self.loc[tuple(slicer)]
if isinstance(ax, MultiIndex):
setattr(result, self._get_axis_name(axis), ax.truncate(before, after))
if copy:
result = result.copy()
return result
def tz_convert(
self: FrameOrSeries, tz, axis=0, level=None, copy: bool_t = True
) -> FrameOrSeries:
"""
Convert tz-aware axis to target time zone.
Parameters
----------
tz : str or tzinfo object
axis : the axis to convert
level : int, str, default None
If axis is a MultiIndex, convert a specific level. Otherwise
must be None.
copy : bool, default True
Also make a copy of the underlying data.
Returns
-------
%(klass)s
Object with time zone converted axis.
Raises
------
TypeError
If the axis is tz-naive.
"""
axis = self._get_axis_number(axis)
ax = self._get_axis(axis)
def _tz_convert(ax, tz):
if not hasattr(ax, "tz_convert"):
if len(ax) > 0:
ax_name = self._get_axis_name(axis)
raise TypeError(
f"{ax_name} is not a valid DatetimeIndex or PeriodIndex"
)
else:
ax = DatetimeIndex([], tz=tz)
else:
ax = ax.tz_convert(tz)
return ax
# if a level is given it must be a MultiIndex level or
# equivalent to the axis name
if isinstance(ax, MultiIndex):
level = ax._get_level_number(level)
new_level = _tz_convert(ax.levels[level], tz)
ax = ax.set_levels(new_level, level=level)
else:
if level not in (None, 0, ax.name):
raise ValueError(f"The level {level} is not valid")
ax = _tz_convert(ax, tz)
result = self._constructor(self._data, copy=copy)
result = result.set_axis(ax, axis=axis, inplace=False)
return result.__finalize__(self)
def tz_localize(
self: FrameOrSeries,
tz,
axis=0,
level=None,
copy: bool_t = True,
ambiguous="raise",
nonexistent: str = "raise",
) -> FrameOrSeries:
"""
Localize tz-naive index of a Series or DataFrame to target time zone.
This operation localizes the Index. To localize the values in a
timezone-naive Series, use :meth:`Series.dt.tz_localize`.
Parameters
----------
tz : str or tzinfo
axis : the axis to localize
level : int, str, default None
If axis ia a MultiIndex, localize a specific level. Otherwise
must be None.
copy : bool, default True
Also make a copy of the underlying data.
ambiguous : 'infer', bool-ndarray, 'NaT', default 'raise'
When clocks moved backward due to DST, ambiguous times may arise.
For example in Central European Time (UTC+01), when going from
03:00 DST to 02:00 non-DST, 02:30:00 local time occurs both at
00:30:00 UTC and at 01:30:00 UTC. In such a situation, the
`ambiguous` parameter dictates how ambiguous times should be
handled.
- 'infer' will attempt to infer fall dst-transition hours based on
order
- bool-ndarray where True signifies a DST time, False designates
a non-DST time (note that this flag is only applicable for
ambiguous times)
- 'NaT' will return NaT where there are ambiguous times
- 'raise' will raise an AmbiguousTimeError if there are ambiguous
times.
nonexistent : str, default 'raise'
A nonexistent time does not exist in a particular timezone
where clocks moved forward due to DST. Valid values are:
- 'shift_forward' will shift the nonexistent time forward to the
closest existing time
- 'shift_backward' will shift the nonexistent time backward to the
closest existing time
- 'NaT' will return NaT where there are nonexistent times
- timedelta objects will shift nonexistent times by the timedelta
- 'raise' will raise an NonExistentTimeError if there are
nonexistent times.
.. versionadded:: 0.24.0
Returns
-------
Series or DataFrame
Same type as the input.
Raises
------
TypeError
If the TimeSeries is tz-aware and tz is not None.
Examples
--------
Localize local times:
>>> s = pd.Series([1],
... index=pd.DatetimeIndex(['2018-09-15 01:30:00']))
>>> s.tz_localize('CET')
2018-09-15 01:30:00+02:00 1
dtype: int64
Be careful with DST changes. When there is sequential data, pandas
can infer the DST time:
>>> s = pd.Series(range(7),
... index=pd.DatetimeIndex(['2018-10-28 01:30:00',
... '2018-10-28 02:00:00',
... '2018-10-28 02:30:00',
... '2018-10-28 02:00:00',
... '2018-10-28 02:30:00',
... '2018-10-28 03:00:00',
... '2018-10-28 03:30:00']))
>>> s.tz_localize('CET', ambiguous='infer')
2018-10-28 01:30:00+02:00 0
2018-10-28 02:00:00+02:00 1
2018-10-28 02:30:00+02:00 2
2018-10-28 02:00:00+01:00 3
2018-10-28 02:30:00+01:00 4
2018-10-28 03:00:00+01:00 5
2018-10-28 03:30:00+01:00 6
dtype: int64
In some cases, inferring the DST is impossible. In such cases, you can
pass an ndarray to the ambiguous parameter to set the DST explicitly
>>> s = pd.Series(range(3),
... index=pd.DatetimeIndex(['2018-10-28 01:20:00',
... '2018-10-28 02:36:00',
... '2018-10-28 03:46:00']))
>>> s.tz_localize('CET', ambiguous=np.array([True, True, False]))
2018-10-28 01:20:00+02:00 0
2018-10-28 02:36:00+02:00 1
2018-10-28 03:46:00+01:00 2
dtype: int64
If the DST transition causes nonexistent times, you can shift these
dates forward or backwards with a timedelta object or `'shift_forward'`
or `'shift_backwards'`.
>>> s = pd.Series(range(2),
... index=pd.DatetimeIndex(['2015-03-29 02:30:00',
... '2015-03-29 03:30:00']))
>>> s.tz_localize('Europe/Warsaw', nonexistent='shift_forward')
2015-03-29 03:00:00+02:00 0
2015-03-29 03:30:00+02:00 1
dtype: int64
>>> s.tz_localize('Europe/Warsaw', nonexistent='shift_backward')
2015-03-29 01:59:59.999999999+01:00 0
2015-03-29 03:30:00+02:00 1
dtype: int64
>>> s.tz_localize('Europe/Warsaw', nonexistent=pd.Timedelta('1H'))
2015-03-29 03:30:00+02:00 0
2015-03-29 03:30:00+02:00 1
dtype: int64
"""
nonexistent_options = ("raise", "NaT", "shift_forward", "shift_backward")
if nonexistent not in nonexistent_options and not isinstance(
nonexistent, timedelta
):
raise ValueError(
"The nonexistent argument must be one of 'raise', "
"'NaT', 'shift_forward', 'shift_backward' or "
"a timedelta object"
)
axis = self._get_axis_number(axis)
ax = self._get_axis(axis)
def _tz_localize(ax, tz, ambiguous, nonexistent):
if not hasattr(ax, "tz_localize"):
if len(ax) > 0:
ax_name = self._get_axis_name(axis)
raise TypeError(
f"{ax_name} is not a valid DatetimeIndex or PeriodIndex"
)
else:
ax = DatetimeIndex([], tz=tz)
else:
ax = ax.tz_localize(tz, ambiguous=ambiguous, nonexistent=nonexistent)
return ax
# if a level is given it must be a MultiIndex level or
# equivalent to the axis name
if isinstance(ax, MultiIndex):
level = ax._get_level_number(level)
new_level = _tz_localize(ax.levels[level], tz, ambiguous, nonexistent)
ax = ax.set_levels(new_level, level=level)
else:
if level not in (None, 0, ax.name):
raise ValueError(f"The level {level} is not valid")
ax = _tz_localize(ax, tz, ambiguous, nonexistent)
result = self._constructor(self._data, copy=copy)
result = result.set_axis(ax, axis=axis, inplace=False)
return result.__finalize__(self)
# ----------------------------------------------------------------------
# Numeric Methods
def abs(self: FrameOrSeries) -> FrameOrSeries:
"""
Return a Series/DataFrame with absolute numeric value of each element.
This function only applies to elements that are all numeric.
Returns
-------
abs
Series/DataFrame containing the absolute value of each element.
See Also
--------
numpy.absolute : Calculate the absolute value element-wise.
Notes
-----
For ``complex`` inputs, ``1.2 + 1j``, the absolute value is
:math:`\\sqrt{ a^2 + b^2 }`.
Examples
--------
Absolute numeric values in a Series.
>>> s = pd.Series([-1.10, 2, -3.33, 4])
>>> s.abs()
0 1.10
1 2.00
2 3.33
3 4.00
dtype: float64
Absolute numeric values in a Series with complex numbers.
>>> s = pd.Series([1.2 + 1j])
>>> s.abs()
0 1.56205
dtype: float64
Absolute numeric values in a Series with a Timedelta element.
>>> s = pd.Series([pd.Timedelta('1 days')])
>>> s.abs()
0 1 days
dtype: timedelta64[ns]
Select rows with data closest to certain value using argsort (from
`StackOverflow <https://stackoverflow.com/a/17758115>`__).
>>> df = pd.DataFrame({
... 'a': [4, 5, 6, 7],
... 'b': [10, 20, 30, 40],
... 'c': [100, 50, -30, -50]
... })
>>> df
a b c
0 4 10 100
1 5 20 50
2 6 30 -30
3 7 40 -50
>>> df.loc[(df.c - 43).abs().argsort()]
a b c
1 5 20 50
0 4 10 100
2 6 30 -30
3 7 40 -50
"""
return np.abs(self)
def describe(
self: FrameOrSeries, percentiles=None, include=None, exclude=None
) -> FrameOrSeries:
"""
Generate descriptive statistics.
Descriptive statistics include those that summarize the central
tendency, dispersion and shape of a
dataset's distribution, excluding ``NaN`` values.
Analyzes both numeric and object series, as well
as ``DataFrame`` column sets of mixed data types. The output
will vary depending on what is provided. Refer to the notes
below for more detail.
Parameters
----------
percentiles : list-like of numbers, optional
The percentiles to include in the output. All should
fall between 0 and 1. The default is
``[.25, .5, .75]``, which returns the 25th, 50th, and
75th percentiles.
include : 'all', list-like of dtypes or None (default), optional
A white list of data types to include in the result. Ignored
for ``Series``. Here are the options:
- 'all' : All columns of the input will be included in the output.
- A list-like of dtypes : Limits the results to the
provided data types.
To limit the result to numeric types submit
``numpy.number``. To limit it instead to object columns submit
the ``numpy.object`` data type. Strings
can also be used in the style of
``select_dtypes`` (e.g. ``df.describe(include=['O'])``). To
select pandas categorical columns, use ``'category'``
- None (default) : The result will include all numeric columns.
exclude : list-like of dtypes or None (default), optional,
A black list of data types to omit from the result. Ignored
for ``Series``. Here are the options:
- A list-like of dtypes : Excludes the provided data types
from the result. To exclude numeric types submit
``numpy.number``. To exclude object columns submit the data
type ``numpy.object``. Strings can also be used in the style of
``select_dtypes`` (e.g. ``df.describe(include=['O'])``). To
exclude pandas categorical columns, use ``'category'``
- None (default) : The result will exclude nothing.
Returns
-------
Series or DataFrame
Summary statistics of the Series or Dataframe provided.
See Also
--------
DataFrame.count: Count number of non-NA/null observations.
DataFrame.max: Maximum of the values in the object.
DataFrame.min: Minimum of the values in the object.
DataFrame.mean: Mean of the values.
DataFrame.std: Standard deviation of the observations.
DataFrame.select_dtypes: Subset of a DataFrame including/excluding
columns based on their dtype.
Notes
-----
For numeric data, the result's index will include ``count``,
``mean``, ``std``, ``min``, ``max`` as well as lower, ``50`` and
upper percentiles. By default the lower percentile is ``25`` and the
upper percentile is ``75``. The ``50`` percentile is the
same as the median.
For object data (e.g. strings or timestamps), the result's index
will include ``count``, ``unique``, ``top``, and ``freq``. The ``top``
is the most common value. The ``freq`` is the most common value's
frequency. Timestamps also include the ``first`` and ``last`` items.
If multiple object values have the highest count, then the
``count`` and ``top`` results will be arbitrarily chosen from
among those with the highest count.
For mixed data types provided via a ``DataFrame``, the default is to
return only an analysis of numeric columns. If the dataframe consists
only of object and categorical data without any numeric columns, the
default is to return an analysis of both the object and categorical
columns. If ``include='all'`` is provided as an option, the result
will include a union of attributes of each type.
The `include` and `exclude` parameters can be used to limit
which columns in a ``DataFrame`` are analyzed for the output.
The parameters are ignored when analyzing a ``Series``.
Examples
--------
Describing a numeric ``Series``.
>>> s = pd.Series([1, 2, 3])
>>> s.describe()
count 3.0
mean 2.0
std 1.0
min 1.0
25% 1.5
50% 2.0
75% 2.5
max 3.0
dtype: float64
Describing a categorical ``Series``.
>>> s = pd.Series(['a', 'a', 'b', 'c'])
>>> s.describe()
count 4
unique 3
top a
freq 2
dtype: object
Describing a timestamp ``Series``.
>>> s = pd.Series([
... np.datetime64("2000-01-01"),
... np.datetime64("2010-01-01"),
... np.datetime64("2010-01-01")
... ])
>>> s.describe()
count 3
unique 2
top 2010-01-01 00:00:00
freq 2
first 2000-01-01 00:00:00
last 2010-01-01 00:00:00
dtype: object
Describing a ``DataFrame``. By default only numeric fields
are returned.
>>> df = pd.DataFrame({'categorical': pd.Categorical(['d','e','f']),
... 'numeric': [1, 2, 3],
... 'object': ['a', 'b', 'c']
... })
>>> df.describe()
numeric
count 3.0
mean 2.0
std 1.0
min 1.0
25% 1.5
50% 2.0
75% 2.5
max 3.0
Describing all columns of a ``DataFrame`` regardless of data type.
>>> df.describe(include='all')
categorical numeric object
count 3 3.0 3
unique 3 NaN 3
top f NaN c
freq 1 NaN 1
mean NaN 2.0 NaN
std NaN 1.0 NaN
min NaN 1.0 NaN
25% NaN 1.5 NaN
50% NaN 2.0 NaN
75% NaN 2.5 NaN
max NaN 3.0 NaN
Describing a column from a ``DataFrame`` by accessing it as
an attribute.
>>> df.numeric.describe()
count 3.0
mean 2.0
std 1.0
min 1.0
25% 1.5
50% 2.0
75% 2.5
max 3.0
Name: numeric, dtype: float64
Including only numeric columns in a ``DataFrame`` description.
>>> df.describe(include=[np.number])
numeric
count 3.0
mean 2.0
std 1.0
min 1.0
25% 1.5
50% 2.0
75% 2.5
max 3.0
Including only string columns in a ``DataFrame`` description.
>>> df.describe(include=[np.object])
object
count 3
unique 3
top c
freq 1
Including only categorical columns from a ``DataFrame`` description.
>>> df.describe(include=['category'])
categorical
count 3
unique 3
top f
freq 1
Excluding numeric columns from a ``DataFrame`` description.
>>> df.describe(exclude=[np.number])
categorical object
count 3 3
unique 3 3
top f c
freq 1 1
Excluding object columns from a ``DataFrame`` description.
>>> df.describe(exclude=[np.object])
categorical numeric
count 3 3.0
unique 3 NaN
top f NaN
freq 1 NaN
mean NaN 2.0
std NaN 1.0
min NaN 1.0
25% NaN 1.5
50% NaN 2.0
75% NaN 2.5
max NaN 3.0
"""
if self.ndim == 2 and self.columns.size == 0:
raise ValueError("Cannot describe a DataFrame without columns")
if percentiles is not None:
# explicit conversion of `percentiles` to list
percentiles = list(percentiles)
# get them all to be in [0, 1]
validate_percentile(percentiles)
# median should always be included
if 0.5 not in percentiles:
percentiles.append(0.5)
percentiles = np.asarray(percentiles)
else:
percentiles = np.array([0.25, 0.5, 0.75])
# sort and check for duplicates
unique_pcts = np.unique(percentiles)
if len(unique_pcts) < len(percentiles):
raise ValueError("percentiles cannot contain duplicates")
percentiles = unique_pcts
formatted_percentiles = format_percentiles(percentiles)
def describe_numeric_1d(series):
stat_index = (
["count", "mean", "std", "min"] + formatted_percentiles + ["max"]
)
d = (
[series.count(), series.mean(), series.std(), series.min()]
+ series.quantile(percentiles).tolist()
+ [series.max()]
)
return pd.Series(d, index=stat_index, name=series.name)
def describe_categorical_1d(data):
names = ["count", "unique"]
objcounts = data.value_counts()
count_unique = len(objcounts[objcounts != 0])
result = [data.count(), count_unique]
dtype = None
if result[1] > 0:
top, freq = objcounts.index[0], objcounts.iloc[0]
names += ["top", "freq"]
result += [top, freq]
# If the DataFrame is empty, set 'top' and 'freq' to None
# to maintain output shape consistency
else:
names += ["top", "freq"]
result += [np.nan, np.nan]
dtype = "object"
return pd.Series(result, index=names, name=data.name, dtype=dtype)
def describe_timestamp_1d(data):
# GH-30164
stat_index = ["count", "mean", "min"] + formatted_percentiles + ["max"]
d = (
[data.count(), data.mean(), data.min()]
+ data.quantile(percentiles).tolist()
+ [data.max()]
)
return pd.Series(d, index=stat_index, name=data.name)
def describe_1d(data):
if is_bool_dtype(data):
return describe_categorical_1d(data)
elif is_numeric_dtype(data):
return describe_numeric_1d(data)
elif is_datetime64_any_dtype(data):
return describe_timestamp_1d(data)
elif is_timedelta64_dtype(data):
return describe_numeric_1d(data)
else:
return describe_categorical_1d(data)
if self.ndim == 1:
return describe_1d(self)
elif (include is None) and (exclude is None):
# when some numerics are found, keep only numerics
data = self.select_dtypes(include=[np.number])
if len(data.columns) == 0:
data = self
elif include == "all":
if exclude is not None:
msg = "exclude must be None when include is 'all'"
raise ValueError(msg)
data = self
else:
data = self.select_dtypes(include=include, exclude=exclude)
ldesc = [describe_1d(s) for _, s in data.items()]
# set a convenient order for rows
names: List[Optional[Hashable]] = []
ldesc_indexes = sorted((x.index for x in ldesc), key=len)
for idxnames in ldesc_indexes:
for name in idxnames:
if name not in names:
names.append(name)
d = pd.concat([x.reindex(names, copy=False) for x in ldesc], axis=1, sort=False)
d.columns = data.columns.copy()
return d
_shared_docs[
"pct_change"
] = """
Percentage change between the current and a prior element.
Computes the percentage change from the immediately previous row by
default. This is useful in comparing the percentage of change in a time
series of elements.
Parameters
----------
periods : int, default 1
Periods to shift for forming percent change.
fill_method : str, default 'pad'
How to handle NAs before computing percent changes.
limit : int, default None
The number of consecutive NAs to fill before stopping.
freq : DateOffset, timedelta, or str, optional
Increment to use from time series API (e.g. 'M' or BDay()).
**kwargs
Additional keyword arguments are passed into
`DataFrame.shift` or `Series.shift`.
Returns
-------
chg : Series or DataFrame
The same type as the calling object.
See Also
--------
Series.diff : Compute the difference of two elements in a Series.
DataFrame.diff : Compute the difference of two elements in a DataFrame.
Series.shift : Shift the index by some number of periods.
DataFrame.shift : Shift the index by some number of periods.
Examples
--------
**Series**
>>> s = pd.Series([90, 91, 85])
>>> s
0 90
1 91
2 85
dtype: int64
>>> s.pct_change()
0 NaN
1 0.011111
2 -0.065934
dtype: float64
>>> s.pct_change(periods=2)
0 NaN
1 NaN
2 -0.055556
dtype: float64
See the percentage change in a Series where filling NAs with last
valid observation forward to next valid.
>>> s = pd.Series([90, 91, None, 85])
>>> s
0 90.0
1 91.0
2 NaN
3 85.0
dtype: float64
>>> s.pct_change(fill_method='ffill')
0 NaN
1 0.011111
2 0.000000
3 -0.065934
dtype: float64
**DataFrame**
Percentage change in French franc, Deutsche Mark, and Italian lira from
1980-01-01 to 1980-03-01.
>>> df = pd.DataFrame({
... 'FR': [4.0405, 4.0963, 4.3149],
... 'GR': [1.7246, 1.7482, 1.8519],
... 'IT': [804.74, 810.01, 860.13]},
... index=['1980-01-01', '1980-02-01', '1980-03-01'])
>>> df
FR GR IT
1980-01-01 4.0405 1.7246 804.74
1980-02-01 4.0963 1.7482 810.01
1980-03-01 4.3149 1.8519 860.13
>>> df.pct_change()
FR GR IT
1980-01-01 NaN NaN NaN
1980-02-01 0.013810 0.013684 0.006549
1980-03-01 0.053365 0.059318 0.061876
Percentage of change in GOOG and APPL stock volume. Shows computing
the percentage change between columns.
>>> df = pd.DataFrame({
... '2016': [1769950, 30586265],
... '2015': [1500923, 40912316],
... '2014': [1371819, 41403351]},
... index=['GOOG', 'APPL'])
>>> df
2016 2015 2014
GOOG 1769950 1500923 1371819
APPL 30586265 40912316 41403351
>>> df.pct_change(axis='columns')
2016 2015 2014
GOOG NaN -0.151997 -0.086016
APPL NaN 0.337604 0.012002
"""
@Appender(_shared_docs["pct_change"] % _shared_doc_kwargs)
def pct_change(
self: FrameOrSeries,
periods=1,
fill_method="pad",
limit=None,
freq=None,
**kwargs,
) -> FrameOrSeries:
# TODO: Not sure if above is correct - need someone to confirm.
axis = self._get_axis_number(kwargs.pop("axis", self._stat_axis_name))
if fill_method is None:
data = self
else:
data = self._ensure_type(
self.fillna(method=fill_method, axis=axis, limit=limit)
)
rs = data.div(data.shift(periods=periods, freq=freq, axis=axis, **kwargs)) - 1
if freq is not None:
# Shift method is implemented differently when freq is not None
# We want to restore the original index
rs = rs.loc[~rs.index.duplicated()]
rs = rs.reindex_like(data)
return rs
def _agg_by_level(self, name, axis=0, level=0, skipna=True, **kwargs):
if axis is None:
raise ValueError("Must specify 'axis' when aggregating by level.")
grouped = self.groupby(level=level, axis=axis, sort=False)
if hasattr(grouped, name) and skipna:
return getattr(grouped, name)(**kwargs)
axis = self._get_axis_number(axis)
method = getattr(type(self), name)
applyf = lambda x: method(x, axis=axis, skipna=skipna, **kwargs)
return grouped.aggregate(applyf)
@classmethod
def _add_numeric_operations(cls):
"""
Add the operations to the cls; evaluate the doc strings again
"""
axis_descr, name, name2 = _doc_parms(cls)
cls.any = _make_logical_function(
cls,
"any",
name,
name2,
axis_descr,
_any_desc,
nanops.nanany,
_any_see_also,
_any_examples,
empty_value=False,
)
cls.all = _make_logical_function(
cls,
"all",
name,
name2,
axis_descr,
_all_desc,
nanops.nanall,
_all_see_also,
_all_examples,
empty_value=True,
)
@Substitution(
desc="Return the mean absolute deviation of the values "
"for the requested axis.",
name1=name,
name2=name2,
axis_descr=axis_descr,
min_count="",
see_also="",
examples="",
)
@Appender(_num_doc_mad)
def mad(self, axis=None, skipna=None, level=None):
if skipna is None:
skipna = True
if axis is None:
axis = self._stat_axis_number
if level is not None:
return self._agg_by_level("mad", axis=axis, level=level, skipna=skipna)
data = self._get_numeric_data()
if axis == 0:
demeaned = data - data.mean(axis=0)
else:
demeaned = data.sub(data.mean(axis=1), axis=0)
return np.abs(demeaned).mean(axis=axis, skipna=skipna)
cls.mad = mad
cls.sem = _make_stat_function_ddof(
cls,
"sem",
name,
name2,
axis_descr,
"Return unbiased standard error of the mean over requested "
"axis.\n\nNormalized by N-1 by default. This can be changed "
"using the ddof argument",
nanops.nansem,
)
cls.var = _make_stat_function_ddof(
cls,
"var",
name,
name2,
axis_descr,
"Return unbiased variance over requested axis.\n\nNormalized by "
"N-1 by default. This can be changed using the ddof argument",
nanops.nanvar,
)
cls.std = _make_stat_function_ddof(
cls,
"std",
name,
name2,
axis_descr,
"Return sample standard deviation over requested axis."
"\n\nNormalized by N-1 by default. This can be changed using the "
"ddof argument",
nanops.nanstd,
)
cls.cummin = _make_cum_function(
cls,
"cummin",
name,
name2,
axis_descr,
"minimum",
np.minimum.accumulate,
"min",
np.inf,
np.nan,
_cummin_examples,
)
cls.cumsum = _make_cum_function(
cls,
"cumsum",
name,
name2,
axis_descr,
"sum",
np.cumsum,
"sum",
0.0,
np.nan,
_cumsum_examples,
)
cls.cumprod = _make_cum_function(
cls,
"cumprod",
name,
name2,
axis_descr,
"product",
np.cumprod,
"prod",
1.0,
np.nan,
_cumprod_examples,
)
cls.cummax = _make_cum_function(
cls,
"cummax",
name,
name2,
axis_descr,
"maximum",
np.maximum.accumulate,
"max",
-np.inf,
np.nan,
_cummax_examples,
)
cls.sum = _make_min_count_stat_function(
cls,
"sum",
name,
name2,
axis_descr,
"""Return the sum of the values for the requested axis.\n
This is equivalent to the method ``numpy.sum``.""",
nanops.nansum,
_stat_func_see_also,
_sum_examples,
)
cls.mean = _make_stat_function(
cls,
"mean",
name,
name2,
axis_descr,
"Return the mean of the values for the requested axis.",
nanops.nanmean,
)
cls.skew = _make_stat_function(
cls,
"skew",
name,
name2,
axis_descr,
"Return unbiased skew over requested axis.\n\nNormalized by N-1.",
nanops.nanskew,
)
cls.kurt = _make_stat_function(
cls,
"kurt",
name,
name2,
axis_descr,
"Return unbiased kurtosis over requested axis.\n\n"
"Kurtosis obtained using Fisher's definition of\n"
"kurtosis (kurtosis of normal == 0.0). Normalized "
"by N-1.",
nanops.nankurt,
)
cls.kurtosis = cls.kurt
cls.prod = _make_min_count_stat_function(
cls,
"prod",
name,
name2,
axis_descr,
"Return the product of the values for the requested axis.",
nanops.nanprod,
examples=_prod_examples,
)
cls.product = cls.prod
cls.median = _make_stat_function(
cls,
"median",
name,
name2,
axis_descr,
"Return the median of the values for the requested axis.",
nanops.nanmedian,
)
cls.max = _make_stat_function(
cls,
"max",
name,
name2,
axis_descr,
"""Return the maximum of the values for the requested axis.\n
If you want the *index* of the maximum, use ``idxmax``. This is
the equivalent of the ``numpy.ndarray`` method ``argmax``.""",
nanops.nanmax,
_stat_func_see_also,
_max_examples,
)
cls.min = _make_stat_function(
cls,
"min",
name,
name2,
axis_descr,
"""Return the minimum of the values for the requested axis.\n
If you want the *index* of the minimum, use ``idxmin``. This is
the equivalent of the ``numpy.ndarray`` method ``argmin``.""",
nanops.nanmin,
_stat_func_see_also,
_min_examples,
)
@classmethod
def _add_series_or_dataframe_operations(cls):
"""
Add the series or dataframe only operations to the cls; evaluate
the doc strings again.
"""
from pandas.core.window import EWM, Expanding, Rolling, Window
@Appender(Rolling.__doc__)
def rolling(
self,
window,
min_periods=None,
center=False,
win_type=None,
on=None,
axis=0,
closed=None,
):
axis = self._get_axis_number(axis)
if win_type is not None:
return Window(
self,
window=window,
min_periods=min_periods,
center=center,
win_type=win_type,
on=on,
axis=axis,
closed=closed,
)
return Rolling(
self,
window=window,
min_periods=min_periods,
center=center,
win_type=win_type,
on=on,
axis=axis,
closed=closed,
)
cls.rolling = rolling
@Appender(Expanding.__doc__)
def expanding(self, min_periods=1, center=False, axis=0):
axis = self._get_axis_number(axis)
return Expanding(self, min_periods=min_periods, center=center, axis=axis)
cls.expanding = expanding
@Appender(EWM.__doc__)
def ewm(
self,
com=None,
span=None,
halflife=None,
alpha=None,
min_periods=0,
adjust=True,
ignore_na=False,
axis=0,
):
axis = self._get_axis_number(axis)
return EWM(
self,
com=com,
span=span,
halflife=halflife,
alpha=alpha,
min_periods=min_periods,
adjust=adjust,
ignore_na=ignore_na,
axis=axis,
)
cls.ewm = ewm
@Appender(_shared_docs["transform"] % dict(axis="", **_shared_doc_kwargs))
def transform(self, func, *args, **kwargs):
result = self.agg(func, *args, **kwargs)
if is_scalar(result) or len(result) != len(self):
raise ValueError("transforms cannot produce aggregated results")
return result
# ----------------------------------------------------------------------
# Misc methods
_shared_docs[
"valid_index"
] = """
Return index for %(position)s non-NA/null value.
Returns
-------
scalar : type of index
Notes
-----
If all elements are non-NA/null, returns None.
Also returns None for empty %(klass)s.
"""
def _find_valid_index(self, how: str):
"""
Retrieves the index of the first valid value.
Parameters
----------
how : {'first', 'last'}
Use this parameter to change between the first or last valid index.
Returns
-------
idx_first_valid : type of index
"""
idxpos = find_valid_index(self._values, how)
if idxpos is None:
return None
return self.index[idxpos]
@Appender(
_shared_docs["valid_index"] % {"position": "first", "klass": "Series/DataFrame"}
)
def first_valid_index(self):
return self._find_valid_index("first")
@Appender(
_shared_docs["valid_index"] % {"position": "last", "klass": "Series/DataFrame"}
)
def last_valid_index(self):
return self._find_valid_index("last")
def _doc_parms(cls):
"""Return a tuple of the doc parms."""
axis_descr = (
f"{{{', '.join(f'{a} ({i})' for i, a in enumerate(cls._AXIS_ORDERS))}}}"
)
name = cls._constructor_sliced.__name__ if cls._AXIS_LEN > 1 else "scalar"
name2 = cls.__name__
return axis_descr, name, name2
_num_doc = """
%(desc)s
Parameters
----------
axis : %(axis_descr)s
Axis for the function to be applied on.
skipna : bool, default True
Exclude NA/null values when computing the result.
level : int or level name, default None
If the axis is a MultiIndex (hierarchical), count along a
particular level, collapsing into a %(name1)s.
numeric_only : bool, default None
Include only float, int, boolean columns. If None, will attempt to use
everything, then use only numeric data. Not implemented for Series.
%(min_count)s\
**kwargs
Additional keyword arguments to be passed to the function.
Returns
-------
%(name1)s or %(name2)s (if level specified)\
%(see_also)s\
%(examples)s
"""
_num_doc_mad = """
%(desc)s
Parameters
----------
axis : %(axis_descr)s
Axis for the function to be applied on.
skipna : bool, default None
Exclude NA/null values when computing the result.
level : int or level name, default None
If the axis is a MultiIndex (hierarchical), count along a
particular level, collapsing into a %(name1)s.
Returns
-------
%(name1)s or %(name2)s (if level specified)\
%(see_also)s\
%(examples)s
"""
_num_ddof_doc = """
%(desc)s
Parameters
----------
axis : %(axis_descr)s
skipna : bool, default True
Exclude NA/null values. If an entire row/column is NA, the result
will be NA.
level : int or level name, default None
If the axis is a MultiIndex (hierarchical), count along a
particular level, collapsing into a %(name1)s.
ddof : int, default 1
Delta Degrees of Freedom. The divisor used in calculations is N - ddof,
where N represents the number of elements.
numeric_only : bool, default None
Include only float, int, boolean columns. If None, will attempt to use
everything, then use only numeric data. Not implemented for Series.
Returns
-------
%(name1)s or %(name2)s (if level specified)\n"""
_bool_doc = """
%(desc)s
Parameters
----------
axis : {0 or 'index', 1 or 'columns', None}, default 0
Indicate which axis or axes should be reduced.
* 0 / 'index' : reduce the index, return a Series whose index is the
original column labels.
* 1 / 'columns' : reduce the columns, return a Series whose index is the
original index.
* None : reduce all axes, return a scalar.
bool_only : bool, default None
Include only boolean columns. If None, will attempt to use everything,
then use only boolean data. Not implemented for Series.
skipna : bool, default True
Exclude NA/null values. If the entire row/column is NA and skipna is
True, then the result will be %(empty_value)s, as for an empty row/column.
If skipna is False, then NA are treated as True, because these are not
equal to zero.
level : int or level name, default None
If the axis is a MultiIndex (hierarchical), count along a
particular level, collapsing into a %(name1)s.
**kwargs : any, default None
Additional keywords have no effect but might be accepted for
compatibility with NumPy.
Returns
-------
%(name1)s or %(name2)s
If level is specified, then, %(name2)s is returned; otherwise, %(name1)s
is returned.
%(see_also)s
%(examples)s"""
_all_desc = """\
Return whether all elements are True, potentially over an axis.
Returns True unless there at least one element within a series or
along a Dataframe axis that is False or equivalent (e.g. zero or
empty)."""
_all_examples = """\
Examples
--------
**Series**
>>> pd.Series([True, True]).all()
True
>>> pd.Series([True, False]).all()
False
>>> pd.Series([]).all()
True
>>> pd.Series([np.nan]).all()
True
>>> pd.Series([np.nan]).all(skipna=False)
True
**DataFrames**
Create a dataframe from a dictionary.
>>> df = pd.DataFrame({'col1': [True, True], 'col2': [True, False]})
>>> df
col1 col2
0 True True
1 True False
Default behaviour checks if column-wise values all return True.
>>> df.all()
col1 True
col2 False
dtype: bool
Specify ``axis='columns'`` to check if row-wise values all return True.
>>> df.all(axis='columns')
0 True
1 False
dtype: bool
Or ``axis=None`` for whether every value is True.
>>> df.all(axis=None)
False
"""
_all_see_also = """\
See Also
--------
Series.all : Return True if all elements are True.
DataFrame.any : Return True if one (or more) elements are True.
"""
_cnum_doc = """
Return cumulative %(desc)s over a DataFrame or Series axis.
Returns a DataFrame or Series of the same size containing the cumulative
%(desc)s.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
The index or the name of the axis. 0 is equivalent to None or 'index'.
skipna : bool, default True
Exclude NA/null values. If an entire row/column is NA, the result
will be NA.
*args, **kwargs :
Additional keywords have no effect but might be accepted for
compatibility with NumPy.
Returns
-------
%(name1)s or %(name2)s
See Also
--------
core.window.Expanding.%(accum_func_name)s : Similar functionality
but ignores ``NaN`` values.
%(name2)s.%(accum_func_name)s : Return the %(desc)s over
%(name2)s axis.
%(name2)s.cummax : Return cumulative maximum over %(name2)s axis.
%(name2)s.cummin : Return cumulative minimum over %(name2)s axis.
%(name2)s.cumsum : Return cumulative sum over %(name2)s axis.
%(name2)s.cumprod : Return cumulative product over %(name2)s axis.
%(examples)s"""
_cummin_examples = """\
Examples
--------
**Series**
>>> s = pd.Series([2, np.nan, 5, -1, 0])
>>> s
0 2.0
1 NaN
2 5.0
3 -1.0
4 0.0
dtype: float64
By default, NA values are ignored.
>>> s.cummin()
0 2.0
1 NaN
2 2.0
3 -1.0
4 -1.0
dtype: float64
To include NA values in the operation, use ``skipna=False``
>>> s.cummin(skipna=False)
0 2.0
1 NaN
2 NaN
3 NaN
4 NaN
dtype: float64
**DataFrame**
>>> df = pd.DataFrame([[2.0, 1.0],
... [3.0, np.nan],
... [1.0, 0.0]],
... columns=list('AB'))
>>> df
A B
0 2.0 1.0
1 3.0 NaN
2 1.0 0.0
By default, iterates over rows and finds the minimum
in each column. This is equivalent to ``axis=None`` or ``axis='index'``.
>>> df.cummin()
A B
0 2.0 1.0
1 2.0 NaN
2 1.0 0.0
To iterate over columns and find the minimum in each row,
use ``axis=1``
>>> df.cummin(axis=1)
A B
0 2.0 1.0
1 3.0 NaN
2 1.0 0.0
"""
_cumsum_examples = """\
Examples
--------
**Series**
>>> s = pd.Series([2, np.nan, 5, -1, 0])
>>> s
0 2.0
1 NaN
2 5.0
3 -1.0
4 0.0
dtype: float64
By default, NA values are ignored.
>>> s.cumsum()
0 2.0
1 NaN
2 7.0
3 6.0
4 6.0
dtype: float64
To include NA values in the operation, use ``skipna=False``
>>> s.cumsum(skipna=False)
0 2.0
1 NaN
2 NaN
3 NaN
4 NaN
dtype: float64
**DataFrame**
>>> df = pd.DataFrame([[2.0, 1.0],
... [3.0, np.nan],
... [1.0, 0.0]],
... columns=list('AB'))
>>> df
A B
0 2.0 1.0
1 3.0 NaN
2 1.0 0.0
By default, iterates over rows and finds the sum
in each column. This is equivalent to ``axis=None`` or ``axis='index'``.
>>> df.cumsum()
A B
0 2.0 1.0
1 5.0 NaN
2 6.0 1.0
To iterate over columns and find the sum in each row,
use ``axis=1``
>>> df.cumsum(axis=1)
A B
0 2.0 3.0
1 3.0 NaN
2 1.0 1.0
"""
_cumprod_examples = """\
Examples
--------
**Series**
>>> s = pd.Series([2, np.nan, 5, -1, 0])
>>> s
0 2.0
1 NaN
2 5.0
3 -1.0
4 0.0
dtype: float64
By default, NA values are ignored.
>>> s.cumprod()
0 2.0
1 NaN
2 10.0
3 -10.0
4 -0.0
dtype: float64
To include NA values in the operation, use ``skipna=False``
>>> s.cumprod(skipna=False)
0 2.0
1 NaN
2 NaN
3 NaN
4 NaN
dtype: float64
**DataFrame**
>>> df = pd.DataFrame([[2.0, 1.0],
... [3.0, np.nan],
... [1.0, 0.0]],
... columns=list('AB'))
>>> df
A B
0 2.0 1.0
1 3.0 NaN
2 1.0 0.0
By default, iterates over rows and finds the product
in each column. This is equivalent to ``axis=None`` or ``axis='index'``.
>>> df.cumprod()
A B
0 2.0 1.0
1 6.0 NaN
2 6.0 0.0
To iterate over columns and find the product in each row,
use ``axis=1``
>>> df.cumprod(axis=1)
A B
0 2.0 2.0
1 3.0 NaN
2 1.0 0.0
"""
_cummax_examples = """\
Examples
--------
**Series**
>>> s = pd.Series([2, np.nan, 5, -1, 0])
>>> s
0 2.0
1 NaN
2 5.0
3 -1.0
4 0.0
dtype: float64
By default, NA values are ignored.
>>> s.cummax()
0 2.0
1 NaN
2 5.0
3 5.0
4 5.0
dtype: float64
To include NA values in the operation, use ``skipna=False``
>>> s.cummax(skipna=False)
0 2.0
1 NaN
2 NaN
3 NaN
4 NaN
dtype: float64
**DataFrame**
>>> df = pd.DataFrame([[2.0, 1.0],
... [3.0, np.nan],
... [1.0, 0.0]],
... columns=list('AB'))
>>> df
A B
0 2.0 1.0
1 3.0 NaN
2 1.0 0.0
By default, iterates over rows and finds the maximum
in each column. This is equivalent to ``axis=None`` or ``axis='index'``.
>>> df.cummax()
A B
0 2.0 1.0
1 3.0 NaN
2 3.0 1.0
To iterate over columns and find the maximum in each row,
use ``axis=1``
>>> df.cummax(axis=1)
A B
0 2.0 2.0
1 3.0 NaN
2 1.0 1.0
"""
_any_see_also = """\
See Also
--------
numpy.any : Numpy version of this method.
Series.any : Return whether any element is True.
Series.all : Return whether all elements are True.
DataFrame.any : Return whether any element is True over requested axis.
DataFrame.all : Return whether all elements are True over requested axis.
"""
_any_desc = """\
Return whether any element is True, potentially over an axis.
Returns False unless there at least one element within a series or
along a Dataframe axis that is True or equivalent (e.g. non-zero or
non-empty)."""
_any_examples = """\
Examples
--------
**Series**
For Series input, the output is a scalar indicating whether any element
is True.
>>> pd.Series([False, False]).any()
False
>>> pd.Series([True, False]).any()
True
>>> pd.Series([]).any()
False
>>> pd.Series([np.nan]).any()
False
>>> pd.Series([np.nan]).any(skipna=False)
True
**DataFrame**
Whether each column contains at least one True element (the default).
>>> df = pd.DataFrame({"A": [1, 2], "B": [0, 2], "C": [0, 0]})
>>> df
A B C
0 1 0 0
1 2 2 0
>>> df.any()
A True
B True
C False
dtype: bool
Aggregating over the columns.
>>> df = pd.DataFrame({"A": [True, False], "B": [1, 2]})
>>> df
A B
0 True 1
1 False 2
>>> df.any(axis='columns')
0 True
1 True
dtype: bool
>>> df = pd.DataFrame({"A": [True, False], "B": [1, 0]})
>>> df
A B
0 True 1
1 False 0
>>> df.any(axis='columns')
0 True
1 False
dtype: bool
Aggregating over the entire DataFrame with ``axis=None``.
>>> df.any(axis=None)
True
`any` for an empty DataFrame is an empty Series.
>>> pd.DataFrame([]).any()
Series([], dtype: bool)
"""
_shared_docs[
"stat_func_example"
] = """
Examples
--------
>>> idx = pd.MultiIndex.from_arrays([
... ['warm', 'warm', 'cold', 'cold'],
... ['dog', 'falcon', 'fish', 'spider']],
... names=['blooded', 'animal'])
>>> s = pd.Series([4, 2, 0, 8], name='legs', index=idx)
>>> s
blooded animal
warm dog 4
falcon 2
cold fish 0
spider 8
Name: legs, dtype: int64
>>> s.{stat_func}()
{default_output}
{verb} using level names, as well as indices.
>>> s.{stat_func}(level='blooded')
blooded
warm {level_output_0}
cold {level_output_1}
Name: legs, dtype: int64
>>> s.{stat_func}(level=0)
blooded
warm {level_output_0}
cold {level_output_1}
Name: legs, dtype: int64"""
_sum_examples = _shared_docs["stat_func_example"].format(
stat_func="sum", verb="Sum", default_output=14, level_output_0=6, level_output_1=8
)
_sum_examples += """
By default, the sum of an empty or all-NA Series is ``0``.
>>> pd.Series([]).sum() # min_count=0 is the default
0.0
This can be controlled with the ``min_count`` parameter. For example, if
you'd like the sum of an empty series to be NaN, pass ``min_count=1``.
>>> pd.Series([]).sum(min_count=1)
nan
Thanks to the ``skipna`` parameter, ``min_count`` handles all-NA and
empty series identically.
>>> pd.Series([np.nan]).sum()
0.0
>>> pd.Series([np.nan]).sum(min_count=1)
nan"""
_max_examples = _shared_docs["stat_func_example"].format(
stat_func="max", verb="Max", default_output=8, level_output_0=4, level_output_1=8
)
_min_examples = _shared_docs["stat_func_example"].format(
stat_func="min", verb="Min", default_output=0, level_output_0=2, level_output_1=0
)
_stat_func_see_also = """
See Also
--------
Series.sum : Return the sum.
Series.min : Return the minimum.
Series.max : Return the maximum.
Series.idxmin : Return the index of the minimum.
Series.idxmax : Return the index of the maximum.
DataFrame.sum : Return the sum over the requested axis.
DataFrame.min : Return the minimum over the requested axis.
DataFrame.max : Return the maximum over the requested axis.
DataFrame.idxmin : Return the index of the minimum over the requested axis.
DataFrame.idxmax : Return the index of the maximum over the requested axis."""
_prod_examples = """
Examples
--------
By default, the product of an empty or all-NA Series is ``1``
>>> pd.Series([]).prod()
1.0
This can be controlled with the ``min_count`` parameter
>>> pd.Series([]).prod(min_count=1)
nan
Thanks to the ``skipna`` parameter, ``min_count`` handles all-NA and
empty series identically.
>>> pd.Series([np.nan]).prod()
1.0
>>> pd.Series([np.nan]).prod(min_count=1)
nan"""
_min_count_stub = """\
min_count : int, default 0
The required number of valid values to perform the operation. If fewer than
``min_count`` non-NA values are present the result will be NA.
.. versionadded:: 0.22.0
Added with the default being 0. This means the sum of an all-NA
or empty Series is 0, and the product of an all-NA or empty
Series is 1.
"""
def _make_min_count_stat_function(
cls, name, name1, name2, axis_descr, desc, f, see_also: str = "", examples: str = ""
):
@Substitution(
desc=desc,
name1=name1,
name2=name2,
axis_descr=axis_descr,
min_count=_min_count_stub,
see_also=see_also,
examples=examples,
)
@Appender(_num_doc)
def stat_func(
self,
axis=None,
skipna=None,
level=None,
numeric_only=None,
min_count=0,
**kwargs,
):
if name == "sum":
nv.validate_sum(tuple(), kwargs)
elif name == "prod":
nv.validate_prod(tuple(), kwargs)
else:
nv.validate_stat_func(tuple(), kwargs, fname=name)
if skipna is None:
skipna = True
if axis is None:
axis = self._stat_axis_number
if level is not None:
return self._agg_by_level(
name, axis=axis, level=level, skipna=skipna, min_count=min_count
)
return self._reduce(
f,
name,
axis=axis,
skipna=skipna,
numeric_only=numeric_only,
min_count=min_count,
)
return set_function_name(stat_func, name, cls)
def _make_stat_function(
cls, name, name1, name2, axis_descr, desc, f, see_also: str = "", examples: str = ""
):
@Substitution(
desc=desc,
name1=name1,
name2=name2,
axis_descr=axis_descr,
min_count="",
see_also=see_also,
examples=examples,
)
@Appender(_num_doc)
def stat_func(
self, axis=None, skipna=None, level=None, numeric_only=None, **kwargs
):
if name == "median":
nv.validate_median(tuple(), kwargs)
else:
nv.validate_stat_func(tuple(), kwargs, fname=name)
if skipna is None:
skipna = True
if axis is None:
axis = self._stat_axis_number
if level is not None:
return self._agg_by_level(name, axis=axis, level=level, skipna=skipna)
return self._reduce(
f, name, axis=axis, skipna=skipna, numeric_only=numeric_only
)
return set_function_name(stat_func, name, cls)
def _make_stat_function_ddof(cls, name, name1, name2, axis_descr, desc, f):
@Substitution(desc=desc, name1=name1, name2=name2, axis_descr=axis_descr)
@Appender(_num_ddof_doc)
def stat_func(
self, axis=None, skipna=None, level=None, ddof=1, numeric_only=None, **kwargs
):
nv.validate_stat_ddof_func(tuple(), kwargs, fname=name)
if skipna is None:
skipna = True
if axis is None:
axis = self._stat_axis_number
if level is not None:
return self._agg_by_level(
name, axis=axis, level=level, skipna=skipna, ddof=ddof
)
return self._reduce(
f, name, axis=axis, numeric_only=numeric_only, skipna=skipna, ddof=ddof
)
return set_function_name(stat_func, name, cls)
def _make_cum_function(
cls,
name,
name1,
name2,
axis_descr,
desc,
accum_func,
accum_func_name,
mask_a,
mask_b,
examples,
):
@Substitution(
desc=desc,
name1=name1,
name2=name2,
axis_descr=axis_descr,
accum_func_name=accum_func_name,
examples=examples,
)
@Appender(_cnum_doc)
def cum_func(self, axis=None, skipna=True, *args, **kwargs):
skipna = nv.validate_cum_func_with_skipna(skipna, args, kwargs, name)
if axis is None:
axis = self._stat_axis_number
else:
axis = self._get_axis_number(axis)
if axis == 1:
return cum_func(self.T, axis=0, skipna=skipna, *args, **kwargs).T
def na_accum_func(blk_values):
# We will be applying this function to block values
if blk_values.dtype.kind in ["m", "M"]:
# GH#30460, GH#29058
# numpy 1.18 started sorting NaTs at the end instead of beginning,
# so we need to work around to maintain backwards-consistency.
orig_dtype = blk_values.dtype
# We need to define mask before masking NaTs
mask = isna(blk_values)
if accum_func == np.minimum.accumulate:
# Note: the accum_func comparison fails as an "is" comparison
y = blk_values.view("i8")
y[mask] = np.iinfo(np.int64).max
changed = True
else:
y = blk_values
changed = False
result = accum_func(y.view("i8"), axis)
if skipna:
np.putmask(result, mask, iNaT)
elif accum_func == np.minimum.accumulate:
# Restore NaTs that we masked previously
nz = (~np.asarray(mask)).nonzero()[0]
if len(nz):
# everything up to the first non-na entry stays NaT
result[: nz[0]] = iNaT
if changed:
# restore NaT elements
y[mask] = iNaT # TODO: could try/finally for this?
if isinstance(blk_values, np.ndarray):
result = result.view(orig_dtype)
else:
# DatetimeArray
result = type(blk_values)._from_sequence(result, dtype=orig_dtype)
elif skipna and not issubclass(
blk_values.dtype.type, (np.integer, np.bool_)
):
vals = blk_values.copy().T
mask = isna(vals)
np.putmask(vals, mask, mask_a)
result = accum_func(vals, axis)
np.putmask(result, mask, mask_b)
else:
result = accum_func(blk_values.T, axis)
# transpose back for ndarray, not for EA
return result.T if hasattr(result, "T") else result
result = self._data.apply(na_accum_func)
d = self._construct_axes_dict()
d["copy"] = False
return self._constructor(result, **d).__finalize__(self)
return set_function_name(cum_func, name, cls)
def _make_logical_function(
cls, name, name1, name2, axis_descr, desc, f, see_also, examples, empty_value
):
@Substitution(
desc=desc,
name1=name1,
name2=name2,
axis_descr=axis_descr,
see_also=see_also,
examples=examples,
empty_value=empty_value,
)
@Appender(_bool_doc)
def logical_func(self, axis=0, bool_only=None, skipna=True, level=None, **kwargs):
nv.validate_logical_func(tuple(), kwargs, fname=name)
if level is not None:
if bool_only is not None:
raise NotImplementedError(
"Option bool_only is not implemented with option level."
)
return self._agg_by_level(name, axis=axis, level=level, skipna=skipna)
return self._reduce(
f,
name,
axis=axis,
skipna=skipna,
numeric_only=bool_only,
filter_type="bool",
)
return set_function_name(logical_func, name, cls)
| BugsInPy/BugsInPy/temp/projects/pandas/bug-55-fixed/pandas/pandas/core/generic.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-55-buggy/pandas/pandas/core/generic.py |
pandas-bug-169 | """
DataFrame
---------
An efficient 2D container for potentially mixed-type time series or other
labeled data series.
Similar to its R counterpart, data.frame, except providing automatic data
alignment and a host of useful data manipulation methods having to do with the
labeling information
"""
import collections
from collections import OrderedDict, abc
import functools
from io import StringIO
import itertools
import sys
from textwrap import dedent
from typing import FrozenSet, List, Optional, Set, Tuple, Type, Union
import warnings
import numpy as np
import numpy.ma as ma
from pandas._config import get_option
from pandas._libs import algos as libalgos, lib
from pandas.compat import PY36, raise_with_traceback
from pandas.compat.numpy import function as nv
from pandas.util._decorators import (
Appender,
Substitution,
deprecate_kwarg,
rewrite_axis_style_signature,
)
from pandas.util._validators import validate_axis_style_args, validate_bool_kwarg
from pandas.core.dtypes.cast import (
cast_scalar_to_array,
coerce_to_dtypes,
find_common_type,
infer_dtype_from_scalar,
invalidate_string_dtypes,
maybe_cast_to_datetime,
maybe_convert_platform,
maybe_downcast_to_dtype,
maybe_infer_to_datetimelike,
maybe_upcast,
maybe_upcast_putmask,
)
from pandas.core.dtypes.common import (
ensure_float64,
ensure_int64,
ensure_platform_int,
infer_dtype_from_object,
is_bool_dtype,
is_datetime64_any_dtype,
is_datetime64tz_dtype,
is_dict_like,
is_dtype_equal,
is_extension_array_dtype,
is_extension_type,
is_float_dtype,
is_hashable,
is_integer,
is_integer_dtype,
is_iterator,
is_list_like,
is_named_tuple,
is_nested_list_like,
is_object_dtype,
is_scalar,
is_sequence,
needs_i8_conversion,
)
from pandas.core.dtypes.generic import (
ABCDataFrame,
ABCIndexClass,
ABCMultiIndex,
ABCSeries,
)
from pandas.core.dtypes.missing import isna, notna
from pandas.core import algorithms, common as com, nanops, ops
from pandas.core.accessor import CachedAccessor
from pandas.core.arrays import Categorical, ExtensionArray
from pandas.core.arrays.datetimelike import DatetimeLikeArrayMixin as DatetimeLikeArray
from pandas.core.arrays.sparse import SparseFrameAccessor
from pandas.core.generic import NDFrame, _shared_docs
from pandas.core.index import (
Index,
MultiIndex,
ensure_index,
ensure_index_from_sequences,
)
from pandas.core.indexes import base as ibase
from pandas.core.indexes.datetimes import DatetimeIndex
from pandas.core.indexes.period import PeriodIndex
from pandas.core.indexing import (
check_bool_indexer,
convert_to_index_sliceable,
maybe_droplevels,
)
from pandas.core.internals import BlockManager
from pandas.core.internals.construction import (
arrays_to_mgr,
get_names_from_index,
init_dict,
init_ndarray,
masked_rec_array_to_mgr,
reorder_arrays,
sanitize_index,
to_arrays,
)
from pandas.core.series import Series
from pandas.io.formats import console, format as fmt
from pandas.io.formats.printing import pprint_thing
import pandas.plotting
# ---------------------------------------------------------------------
# Docstring templates
_shared_doc_kwargs = dict(
axes="index, columns",
klass="DataFrame",
axes_single_arg="{0 or 'index', 1 or 'columns'}",
axis="""axis : {0 or 'index', 1 or 'columns'}, default 0
If 0 or 'index': apply function to each column.
If 1 or 'columns': apply function to each row.""",
optional_by="""
by : str or list of str
Name or list of names to sort by.
- if `axis` is 0 or `'index'` then `by` may contain index
levels and/or column labels
- if `axis` is 1 or `'columns'` then `by` may contain column
levels and/or index labels
.. versionchanged:: 0.23.0
Allow specifying index or column level names.""",
versionadded_to_excel="",
optional_labels="""labels : array-like, optional
New labels / index to conform the axis specified by 'axis' to.""",
optional_axis="""axis : int or str, optional
Axis to target. Can be either the axis name ('index', 'columns')
or number (0, 1).""",
)
_numeric_only_doc = """numeric_only : boolean, default None
Include only float, int, boolean data. If None, will attempt to use
everything, then use only numeric data
"""
_merge_doc = """
Merge DataFrame or named Series objects with a database-style join.
The join is done on columns or indexes. If joining columns on
columns, the DataFrame indexes *will be ignored*. Otherwise if joining indexes
on indexes or indexes on a column or columns, the index will be passed on.
Parameters
----------%s
right : DataFrame or named Series
Object to merge with.
how : {'left', 'right', 'outer', 'inner'}, default 'inner'
Type of merge to be performed.
* left: use only keys from left frame, similar to a SQL left outer join;
preserve key order.
* right: use only keys from right frame, similar to a SQL right outer join;
preserve key order.
* outer: use union of keys from both frames, similar to a SQL full outer
join; sort keys lexicographically.
* inner: use intersection of keys from both frames, similar to a SQL inner
join; preserve the order of the left keys.
on : label or list
Column or index level names to join on. These must be found in both
DataFrames. If `on` is None and not merging on indexes then this defaults
to the intersection of the columns in both DataFrames.
left_on : label or list, or array-like
Column or index level names to join on in the left DataFrame. Can also
be an array or list of arrays of the length of the left DataFrame.
These arrays are treated as if they are columns.
right_on : label or list, or array-like
Column or index level names to join on in the right DataFrame. Can also
be an array or list of arrays of the length of the right DataFrame.
These arrays are treated as if they are columns.
left_index : bool, default False
Use the index from the left DataFrame as the join key(s). If it is a
MultiIndex, the number of keys in the other DataFrame (either the index
or a number of columns) must match the number of levels.
right_index : bool, default False
Use the index from the right DataFrame as the join key. Same caveats as
left_index.
sort : bool, default False
Sort the join keys lexicographically in the result DataFrame. If False,
the order of the join keys depends on the join type (how keyword).
suffixes : tuple of (str, str), default ('_x', '_y')
Suffix to apply to overlapping column names in the left and right
side, respectively. To raise an exception on overlapping columns use
(False, False).
copy : bool, default True
If False, avoid copy if possible.
indicator : bool or str, default False
If True, adds a column to output DataFrame called "_merge" with
information on the source of each row.
If string, column with information on source of each row will be added to
output DataFrame, and column will be named value of string.
Information column is Categorical-type and takes on a value of "left_only"
for observations whose merge key only appears in 'left' DataFrame,
"right_only" for observations whose merge key only appears in 'right'
DataFrame, and "both" if the observation's merge key is found in both.
validate : str, optional
If specified, checks if merge is of specified type.
* "one_to_one" or "1:1": check if merge keys are unique in both
left and right datasets.
* "one_to_many" or "1:m": check if merge keys are unique in left
dataset.
* "many_to_one" or "m:1": check if merge keys are unique in right
dataset.
* "many_to_many" or "m:m": allowed, but does not result in checks.
.. versionadded:: 0.21.0
Returns
-------
DataFrame
A DataFrame of the two merged objects.
See Also
--------
merge_ordered : Merge with optional filling/interpolation.
merge_asof : Merge on nearest keys.
DataFrame.join : Similar method using indices.
Notes
-----
Support for specifying index levels as the `on`, `left_on`, and
`right_on` parameters was added in version 0.23.0
Support for merging named Series objects was added in version 0.24.0
Examples
--------
>>> df1 = pd.DataFrame({'lkey': ['foo', 'bar', 'baz', 'foo'],
... 'value': [1, 2, 3, 5]})
>>> df2 = pd.DataFrame({'rkey': ['foo', 'bar', 'baz', 'foo'],
... 'value': [5, 6, 7, 8]})
>>> df1
lkey value
0 foo 1
1 bar 2
2 baz 3
3 foo 5
>>> df2
rkey value
0 foo 5
1 bar 6
2 baz 7
3 foo 8
Merge df1 and df2 on the lkey and rkey columns. The value columns have
the default suffixes, _x and _y, appended.
>>> df1.merge(df2, left_on='lkey', right_on='rkey')
lkey value_x rkey value_y
0 foo 1 foo 5
1 foo 1 foo 8
2 foo 5 foo 5
3 foo 5 foo 8
4 bar 2 bar 6
5 baz 3 baz 7
Merge DataFrames df1 and df2 with specified left and right suffixes
appended to any overlapping columns.
>>> df1.merge(df2, left_on='lkey', right_on='rkey',
... suffixes=('_left', '_right'))
lkey value_left rkey value_right
0 foo 1 foo 5
1 foo 1 foo 8
2 foo 5 foo 5
3 foo 5 foo 8
4 bar 2 bar 6
5 baz 3 baz 7
Merge DataFrames df1 and df2, but raise an exception if the DataFrames have
any overlapping columns.
>>> df1.merge(df2, left_on='lkey', right_on='rkey', suffixes=(False, False))
Traceback (most recent call last):
...
ValueError: columns overlap but no suffix specified:
Index(['value'], dtype='object')
"""
# -----------------------------------------------------------------------
# DataFrame class
class DataFrame(NDFrame):
"""
Two-dimensional size-mutable, potentially heterogeneous tabular data
structure with labeled axes (rows and columns). Arithmetic operations
align on both row and column labels. Can be thought of as a dict-like
container for Series objects. The primary pandas data structure.
Parameters
----------
data : ndarray (structured or homogeneous), Iterable, dict, or DataFrame
Dict can contain Series, arrays, constants, or list-like objects
.. versionchanged :: 0.23.0
If data is a dict, column order follows insertion-order for
Python 3.6 and later.
.. versionchanged :: 0.25.0
If data is a list of dicts, column order follows insertion-order
Python 3.6 and later.
index : Index or array-like
Index to use for resulting frame. Will default to RangeIndex if
no indexing information part of input data and no index provided
columns : Index or array-like
Column labels to use for resulting frame. Will default to
RangeIndex (0, 1, 2, ..., n) if no column labels are provided
dtype : dtype, default None
Data type to force. Only a single dtype is allowed. If None, infer
copy : boolean, default False
Copy data from inputs. Only affects DataFrame / 2d ndarray input
See Also
--------
DataFrame.from_records : Constructor from tuples, also record arrays.
DataFrame.from_dict : From dicts of Series, arrays, or dicts.
DataFrame.from_items : From sequence of (key, value) pairs
read_csv, pandas.read_table, pandas.read_clipboard.
Examples
--------
Constructing DataFrame from a dictionary.
>>> d = {'col1': [1, 2], 'col2': [3, 4]}
>>> df = pd.DataFrame(data=d)
>>> df
col1 col2
0 1 3
1 2 4
Notice that the inferred dtype is int64.
>>> df.dtypes
col1 int64
col2 int64
dtype: object
To enforce a single dtype:
>>> df = pd.DataFrame(data=d, dtype=np.int8)
>>> df.dtypes
col1 int8
col2 int8
dtype: object
Constructing DataFrame from numpy ndarray:
>>> df2 = pd.DataFrame(np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]]),
... columns=['a', 'b', 'c'])
>>> df2
a b c
0 1 2 3
1 4 5 6
2 7 8 9
"""
@property
def _constructor(self):
return DataFrame
_constructor_sliced = Series # type: Type[Series]
_deprecations = NDFrame._deprecations | frozenset(
["from_items"]
) # type: FrozenSet[str]
_accessors = set() # type: Set[str]
@property
def _constructor_expanddim(self):
raise NotImplementedError("Not supported for DataFrames!")
# ----------------------------------------------------------------------
# Constructors
def __init__(self, data=None, index=None, columns=None, dtype=None, copy=False):
if data is None:
data = {}
if dtype is not None:
dtype = self._validate_dtype(dtype)
if isinstance(data, DataFrame):
data = data._data
if isinstance(data, BlockManager):
mgr = self._init_mgr(
data, axes=dict(index=index, columns=columns), dtype=dtype, copy=copy
)
elif isinstance(data, dict):
mgr = init_dict(data, index, columns, dtype=dtype)
elif isinstance(data, ma.MaskedArray):
import numpy.ma.mrecords as mrecords
# masked recarray
if isinstance(data, mrecords.MaskedRecords):
mgr = masked_rec_array_to_mgr(data, index, columns, dtype, copy)
# a masked array
else:
mask = ma.getmaskarray(data)
if mask.any():
data, fill_value = maybe_upcast(data, copy=True)
data.soften_mask() # set hardmask False if it was True
data[mask] = fill_value
else:
data = data.copy()
mgr = init_ndarray(data, index, columns, dtype=dtype, copy=copy)
elif isinstance(data, (np.ndarray, Series, Index)):
if data.dtype.names:
data_columns = list(data.dtype.names)
data = {k: data[k] for k in data_columns}
if columns is None:
columns = data_columns
mgr = init_dict(data, index, columns, dtype=dtype)
elif getattr(data, "name", None) is not None:
mgr = init_dict({data.name: data}, index, columns, dtype=dtype)
else:
mgr = init_ndarray(data, index, columns, dtype=dtype, copy=copy)
# For data is list-like, or Iterable (will consume into list)
elif isinstance(data, abc.Iterable) and not isinstance(data, (str, bytes)):
if not isinstance(data, abc.Sequence):
data = list(data)
if len(data) > 0:
if is_list_like(data[0]) and getattr(data[0], "ndim", 1) == 1:
if is_named_tuple(data[0]) and columns is None:
columns = data[0]._fields
arrays, columns = to_arrays(data, columns, dtype=dtype)
columns = ensure_index(columns)
# set the index
if index is None:
if isinstance(data[0], Series):
index = get_names_from_index(data)
elif isinstance(data[0], Categorical):
index = ibase.default_index(len(data[0]))
else:
index = ibase.default_index(len(data))
mgr = arrays_to_mgr(arrays, columns, index, columns, dtype=dtype)
else:
mgr = init_ndarray(data, index, columns, dtype=dtype, copy=copy)
else:
mgr = init_dict({}, index, columns, dtype=dtype)
else:
try:
arr = np.array(data, dtype=dtype, copy=copy)
except (ValueError, TypeError) as e:
exc = TypeError(
"DataFrame constructor called with "
"incompatible data and dtype: {e}".format(e=e)
)
raise_with_traceback(exc)
if arr.ndim == 0 and index is not None and columns is not None:
values = cast_scalar_to_array(
(len(index), len(columns)), data, dtype=dtype
)
mgr = init_ndarray(
values, index, columns, dtype=values.dtype, copy=False
)
else:
raise ValueError("DataFrame constructor not properly called!")
NDFrame.__init__(self, mgr, fastpath=True)
# ----------------------------------------------------------------------
@property
def axes(self):
"""
Return a list representing the axes of the DataFrame.
It has the row axis labels and column axis labels as the only members.
They are returned in that order.
Examples
--------
>>> df = pd.DataFrame({'col1': [1, 2], 'col2': [3, 4]})
>>> df.axes
[RangeIndex(start=0, stop=2, step=1), Index(['col1', 'col2'],
dtype='object')]
"""
return [self.index, self.columns]
@property
def shape(self):
"""
Return a tuple representing the dimensionality of the DataFrame.
See Also
--------
ndarray.shape
Examples
--------
>>> df = pd.DataFrame({'col1': [1, 2], 'col2': [3, 4]})
>>> df.shape
(2, 2)
>>> df = pd.DataFrame({'col1': [1, 2], 'col2': [3, 4],
... 'col3': [5, 6]})
>>> df.shape
(2, 3)
"""
return len(self.index), len(self.columns)
@property
def _is_homogeneous_type(self):
"""
Whether all the columns in a DataFrame have the same type.
Returns
-------
bool
Examples
--------
>>> DataFrame({"A": [1, 2], "B": [3, 4]})._is_homogeneous_type
True
>>> DataFrame({"A": [1, 2], "B": [3.0, 4.0]})._is_homogeneous_type
False
Items with the same type but different sizes are considered
different types.
>>> DataFrame({
... "A": np.array([1, 2], dtype=np.int32),
... "B": np.array([1, 2], dtype=np.int64)})._is_homogeneous_type
False
"""
if self._data.any_extension_types:
return len({block.dtype for block in self._data.blocks}) == 1
else:
return not self._data.is_mixed_type
# ----------------------------------------------------------------------
# Rendering Methods
def _repr_fits_vertical_(self):
"""
Check length against max_rows.
"""
max_rows = get_option("display.max_rows")
return len(self) <= max_rows
def _repr_fits_horizontal_(self, ignore_width=False):
"""
Check if full repr fits in horizontal boundaries imposed by the display
options width and max_columns.
In case off non-interactive session, no boundaries apply.
`ignore_width` is here so ipnb+HTML output can behave the way
users expect. display.max_columns remains in effect.
GH3541, GH3573
"""
width, height = console.get_console_size()
max_columns = get_option("display.max_columns")
nb_columns = len(self.columns)
# exceed max columns
if (max_columns and nb_columns > max_columns) or (
(not ignore_width) and width and nb_columns > (width // 2)
):
return False
# used by repr_html under IPython notebook or scripts ignore terminal
# dims
if ignore_width or not console.in_interactive_session():
return True
if get_option("display.width") is not None or console.in_ipython_frontend():
# check at least the column row for excessive width
max_rows = 1
else:
max_rows = get_option("display.max_rows")
# when auto-detecting, so width=None and not in ipython front end
# check whether repr fits horizontal by actually checking
# the width of the rendered repr
buf = StringIO()
# only care about the stuff we'll actually print out
# and to_string on entire frame may be expensive
d = self
if not (max_rows is None): # unlimited rows
# min of two, where one may be None
d = d.iloc[: min(max_rows, len(d))]
else:
return True
d.to_string(buf=buf)
value = buf.getvalue()
repr_width = max(len(l) for l in value.split("\n"))
return repr_width < width
def _info_repr(self):
"""
True if the repr should show the info view.
"""
info_repr_option = get_option("display.large_repr") == "info"
return info_repr_option and not (
self._repr_fits_horizontal_() and self._repr_fits_vertical_()
)
def __repr__(self):
"""
Return a string representation for a particular DataFrame.
"""
buf = StringIO("")
if self._info_repr():
self.info(buf=buf)
return buf.getvalue()
max_rows = get_option("display.max_rows")
min_rows = get_option("display.min_rows")
max_cols = get_option("display.max_columns")
show_dimensions = get_option("display.show_dimensions")
if get_option("display.expand_frame_repr"):
width, _ = console.get_console_size()
else:
width = None
self.to_string(
buf=buf,
max_rows=max_rows,
min_rows=min_rows,
max_cols=max_cols,
line_width=width,
show_dimensions=show_dimensions,
)
return buf.getvalue()
def _repr_html_(self):
"""
Return a html representation for a particular DataFrame.
Mainly for IPython notebook.
"""
if self._info_repr():
buf = StringIO("")
self.info(buf=buf)
# need to escape the <class>, should be the first line.
val = buf.getvalue().replace("<", r"<", 1)
val = val.replace(">", r">", 1)
return "<pre>" + val + "</pre>"
if get_option("display.notebook_repr_html"):
max_rows = get_option("display.max_rows")
max_cols = get_option("display.max_columns")
show_dimensions = get_option("display.show_dimensions")
return self.to_html(
max_rows=max_rows,
max_cols=max_cols,
show_dimensions=show_dimensions,
notebook=True,
)
else:
return None
@Substitution(
header="Write out the column names. If a list of strings "
"is given, it is assumed to be aliases for the "
"column names",
col_space_type="int",
col_space="The minimum width of each column",
)
@Substitution(shared_params=fmt.common_docstring, returns=fmt.return_docstring)
def to_string(
self,
buf=None,
columns=None,
col_space=None,
header=True,
index=True,
na_rep="NaN",
formatters=None,
float_format=None,
sparsify=None,
index_names=True,
justify=None,
max_rows=None,
min_rows=None,
max_cols=None,
show_dimensions=False,
decimal=".",
line_width=None,
):
"""
Render a DataFrame to a console-friendly tabular output.
%(shared_params)s
line_width : int, optional
Width to wrap a line in characters.
%(returns)s
See Also
--------
to_html : Convert DataFrame to HTML.
Examples
--------
>>> d = {'col1': [1, 2, 3], 'col2': [4, 5, 6]}
>>> df = pd.DataFrame(d)
>>> print(df.to_string())
col1 col2
0 1 4
1 2 5
2 3 6
"""
formatter = fmt.DataFrameFormatter(
self,
buf=buf,
columns=columns,
col_space=col_space,
na_rep=na_rep,
formatters=formatters,
float_format=float_format,
sparsify=sparsify,
justify=justify,
index_names=index_names,
header=header,
index=index,
min_rows=min_rows,
max_rows=max_rows,
max_cols=max_cols,
show_dimensions=show_dimensions,
decimal=decimal,
line_width=line_width,
)
formatter.to_string()
if buf is None:
result = formatter.buf.getvalue()
return result
# ----------------------------------------------------------------------
@property
def style(self):
"""
Property returning a Styler object containing methods for
building a styled HTML representation fo the DataFrame.
See Also
--------
io.formats.style.Styler
"""
from pandas.io.formats.style import Styler
return Styler(self)
_shared_docs[
"items"
] = r"""
Iterator over (column name, Series) pairs.
Iterates over the DataFrame columns, returning a tuple with
the column name and the content as a Series.
%s
label : object
The column names for the DataFrame being iterated over.
content : Series
The column entries belonging to each label, as a Series.
See Also
--------
DataFrame.iterrows : Iterate over DataFrame rows as
(index, Series) pairs.
DataFrame.itertuples : Iterate over DataFrame rows as namedtuples
of the values.
Examples
--------
>>> df = pd.DataFrame({'species': ['bear', 'bear', 'marsupial'],
... 'population': [1864, 22000, 80000]},
... index=['panda', 'polar', 'koala'])
>>> df
species population
panda bear 1864
polar bear 22000
koala marsupial 80000
>>> for label, content in df.items():
... print('label:', label)
... print('content:', content, sep='\n')
...
label: species
content:
panda bear
polar bear
koala marsupial
Name: species, dtype: object
label: population
content:
panda 1864
polar 22000
koala 80000
Name: population, dtype: int64
"""
@Appender(_shared_docs["items"] % "Yields\n ------")
def items(self):
if self.columns.is_unique and hasattr(self, "_item_cache"):
for k in self.columns:
yield k, self._get_item_cache(k)
else:
for i, k in enumerate(self.columns):
yield k, self._ixs(i, axis=1)
@Appender(_shared_docs["items"] % "Returns\n -------")
def iteritems(self):
return self.items()
def iterrows(self):
"""
Iterate over DataFrame rows as (index, Series) pairs.
Yields
------
index : label or tuple of label
The index of the row. A tuple for a `MultiIndex`.
data : Series
The data of the row as a Series.
it : generator
A generator that iterates over the rows of the frame.
See Also
--------
itertuples : Iterate over DataFrame rows as namedtuples of the values.
items : Iterate over (column name, Series) pairs.
Notes
-----
1. Because ``iterrows`` returns a Series for each row,
it does **not** preserve dtypes across the rows (dtypes are
preserved across columns for DataFrames). For example,
>>> df = pd.DataFrame([[1, 1.5]], columns=['int', 'float'])
>>> row = next(df.iterrows())[1]
>>> row
int 1.0
float 1.5
Name: 0, dtype: float64
>>> print(row['int'].dtype)
float64
>>> print(df['int'].dtype)
int64
To preserve dtypes while iterating over the rows, it is better
to use :meth:`itertuples` which returns namedtuples of the values
and which is generally faster than ``iterrows``.
2. You should **never modify** something you are iterating over.
This is not guaranteed to work in all cases. Depending on the
data types, the iterator returns a copy and not a view, and writing
to it will have no effect.
"""
columns = self.columns
klass = self._constructor_sliced
for k, v in zip(self.index, self.values):
s = klass(v, index=columns, name=k)
yield k, s
def itertuples(self, index=True, name="Pandas"):
"""
Iterate over DataFrame rows as namedtuples.
Parameters
----------
index : bool, default True
If True, return the index as the first element of the tuple.
name : str or None, default "Pandas"
The name of the returned namedtuples or None to return regular
tuples.
Returns
-------
iterator
An object to iterate over namedtuples for each row in the
DataFrame with the first field possibly being the index and
following fields being the column values.
See Also
--------
DataFrame.iterrows : Iterate over DataFrame rows as (index, Series)
pairs.
DataFrame.items : Iterate over (column name, Series) pairs.
Notes
-----
The column names will be renamed to positional names if they are
invalid Python identifiers, repeated, or start with an underscore.
With a large number of columns (>255), regular tuples are returned.
Examples
--------
>>> df = pd.DataFrame({'num_legs': [4, 2], 'num_wings': [0, 2]},
... index=['dog', 'hawk'])
>>> df
num_legs num_wings
dog 4 0
hawk 2 2
>>> for row in df.itertuples():
... print(row)
...
Pandas(Index='dog', num_legs=4, num_wings=0)
Pandas(Index='hawk', num_legs=2, num_wings=2)
By setting the `index` parameter to False we can remove the index
as the first element of the tuple:
>>> for row in df.itertuples(index=False):
... print(row)
...
Pandas(num_legs=4, num_wings=0)
Pandas(num_legs=2, num_wings=2)
With the `name` parameter set we set a custom name for the yielded
namedtuples:
>>> for row in df.itertuples(name='Animal'):
... print(row)
...
Animal(Index='dog', num_legs=4, num_wings=0)
Animal(Index='hawk', num_legs=2, num_wings=2)
"""
arrays = []
fields = list(self.columns)
if index:
arrays.append(self.index)
fields.insert(0, "Index")
# use integer indexing because of possible duplicate column names
arrays.extend(self.iloc[:, k] for k in range(len(self.columns)))
# Python 3 supports at most 255 arguments to constructor
if name is not None and len(self.columns) + index < 256:
itertuple = collections.namedtuple(name, fields, rename=True)
return map(itertuple._make, zip(*arrays))
# fallback to regular tuples
return zip(*arrays)
def __len__(self):
"""
Returns length of info axis, but here we use the index.
"""
return len(self.index)
def dot(self, other):
"""
Compute the matrix multiplication between the DataFrame and other.
This method computes the matrix product between the DataFrame and the
values of an other Series, DataFrame or a numpy array.
It can also be called using ``self @ other`` in Python >= 3.5.
Parameters
----------
other : Series, DataFrame or array-like
The other object to compute the matrix product with.
Returns
-------
Series or DataFrame
If other is a Series, return the matrix product between self and
other as a Serie. If other is a DataFrame or a numpy.array, return
the matrix product of self and other in a DataFrame of a np.array.
See Also
--------
Series.dot: Similar method for Series.
Notes
-----
The dimensions of DataFrame and other must be compatible in order to
compute the matrix multiplication. In addition, the column names of
DataFrame and the index of other must contain the same values, as they
will be aligned prior to the multiplication.
The dot method for Series computes the inner product, instead of the
matrix product here.
Examples
--------
Here we multiply a DataFrame with a Series.
>>> df = pd.DataFrame([[0, 1, -2, -1], [1, 1, 1, 1]])
>>> s = pd.Series([1, 1, 2, 1])
>>> df.dot(s)
0 -4
1 5
dtype: int64
Here we multiply a DataFrame with another DataFrame.
>>> other = pd.DataFrame([[0, 1], [1, 2], [-1, -1], [2, 0]])
>>> df.dot(other)
0 1
0 1 4
1 2 2
Note that the dot method give the same result as @
>>> df @ other
0 1
0 1 4
1 2 2
The dot method works also if other is an np.array.
>>> arr = np.array([[0, 1], [1, 2], [-1, -1], [2, 0]])
>>> df.dot(arr)
0 1
0 1 4
1 2 2
Note how shuffling of the objects does not change the result.
>>> s2 = s.reindex([1, 0, 2, 3])
>>> df.dot(s2)
0 -4
1 5
dtype: int64
"""
if isinstance(other, (Series, DataFrame)):
common = self.columns.union(other.index)
if len(common) > len(self.columns) or len(common) > len(other.index):
raise ValueError("matrices are not aligned")
left = self.reindex(columns=common, copy=False)
right = other.reindex(index=common, copy=False)
lvals = left.values
rvals = right.values
else:
left = self
lvals = self.values
rvals = np.asarray(other)
if lvals.shape[1] != rvals.shape[0]:
raise ValueError(
"Dot product shape mismatch, "
"{s} vs {r}".format(s=lvals.shape, r=rvals.shape)
)
if isinstance(other, DataFrame):
return self._constructor(
np.dot(lvals, rvals), index=left.index, columns=other.columns
)
elif isinstance(other, Series):
return Series(np.dot(lvals, rvals), index=left.index)
elif isinstance(rvals, (np.ndarray, Index)):
result = np.dot(lvals, rvals)
if result.ndim == 2:
return self._constructor(result, index=left.index)
else:
return Series(result, index=left.index)
else: # pragma: no cover
raise TypeError("unsupported type: {oth}".format(oth=type(other)))
def __matmul__(self, other):
"""
Matrix multiplication using binary `@` operator in Python>=3.5.
"""
return self.dot(other)
def __rmatmul__(self, other):
"""
Matrix multiplication using binary `@` operator in Python>=3.5.
"""
return self.T.dot(np.transpose(other)).T
# ----------------------------------------------------------------------
# IO methods (to / from other formats)
@classmethod
def from_dict(cls, data, orient="columns", dtype=None, columns=None):
"""
Construct DataFrame from dict of array-like or dicts.
Creates DataFrame object from dictionary by columns or by index
allowing dtype specification.
Parameters
----------
data : dict
Of the form {field : array-like} or {field : dict}.
orient : {'columns', 'index'}, default 'columns'
The "orientation" of the data. If the keys of the passed dict
should be the columns of the resulting DataFrame, pass 'columns'
(default). Otherwise if the keys should be rows, pass 'index'.
dtype : dtype, default None
Data type to force, otherwise infer.
columns : list, default None
Column labels to use when ``orient='index'``. Raises a ValueError
if used with ``orient='columns'``.
.. versionadded:: 0.23.0
Returns
-------
DataFrame
See Also
--------
DataFrame.from_records : DataFrame from ndarray (structured
dtype), list of tuples, dict, or DataFrame.
DataFrame : DataFrame object creation using constructor.
Examples
--------
By default the keys of the dict become the DataFrame columns:
>>> data = {'col_1': [3, 2, 1, 0], 'col_2': ['a', 'b', 'c', 'd']}
>>> pd.DataFrame.from_dict(data)
col_1 col_2
0 3 a
1 2 b
2 1 c
3 0 d
Specify ``orient='index'`` to create the DataFrame using dictionary
keys as rows:
>>> data = {'row_1': [3, 2, 1, 0], 'row_2': ['a', 'b', 'c', 'd']}
>>> pd.DataFrame.from_dict(data, orient='index')
0 1 2 3
row_1 3 2 1 0
row_2 a b c d
When using the 'index' orientation, the column names can be
specified manually:
>>> pd.DataFrame.from_dict(data, orient='index',
... columns=['A', 'B', 'C', 'D'])
A B C D
row_1 3 2 1 0
row_2 a b c d
"""
index = None
orient = orient.lower()
if orient == "index":
if len(data) > 0:
# TODO speed up Series case
if isinstance(list(data.values())[0], (Series, dict)):
data = _from_nested_dict(data)
else:
data, index = list(data.values()), list(data.keys())
elif orient == "columns":
if columns is not None:
raise ValueError(
"cannot use columns parameter with " "orient='columns'"
)
else: # pragma: no cover
raise ValueError("only recognize index or columns for orient")
return cls(data, index=index, columns=columns, dtype=dtype)
def to_numpy(self, dtype=None, copy=False):
"""
Convert the DataFrame to a NumPy array.
.. versionadded:: 0.24.0
By default, the dtype of the returned array will be the common NumPy
dtype of all types in the DataFrame. For example, if the dtypes are
``float16`` and ``float32``, the results dtype will be ``float32``.
This may require copying data and coercing values, which may be
expensive.
Parameters
----------
dtype : str or numpy.dtype, optional
The dtype to pass to :meth:`numpy.asarray`
copy : bool, default False
Whether to ensure that the returned value is a not a view on
another array. Note that ``copy=False`` does not *ensure* that
``to_numpy()`` is no-copy. Rather, ``copy=True`` ensure that
a copy is made, even if not strictly necessary.
Returns
-------
numpy.ndarray
See Also
--------
Series.to_numpy : Similar method for Series.
Examples
--------
>>> pd.DataFrame({"A": [1, 2], "B": [3, 4]}).to_numpy()
array([[1, 3],
[2, 4]])
With heterogenous data, the lowest common type will have to
be used.
>>> df = pd.DataFrame({"A": [1, 2], "B": [3.0, 4.5]})
>>> df.to_numpy()
array([[1. , 3. ],
[2. , 4.5]])
For a mix of numeric and non-numeric types, the output array will
have object dtype.
>>> df['C'] = pd.date_range('2000', periods=2)
>>> df.to_numpy()
array([[1, 3.0, Timestamp('2000-01-01 00:00:00')],
[2, 4.5, Timestamp('2000-01-02 00:00:00')]], dtype=object)
"""
result = np.array(self.values, dtype=dtype, copy=copy)
return result
def to_dict(self, orient="dict", into=dict):
"""
Convert the DataFrame to a dictionary.
The type of the key-value pairs can be customized with the parameters
(see below).
Parameters
----------
orient : str {'dict', 'list', 'series', 'split', 'records', 'index'}
Determines the type of the values of the dictionary.
- 'dict' (default) : dict like {column -> {index -> value}}
- 'list' : dict like {column -> [values]}
- 'series' : dict like {column -> Series(values)}
- 'split' : dict like
{'index' -> [index], 'columns' -> [columns], 'data' -> [values]}
- 'records' : list like
[{column -> value}, ... , {column -> value}]
- 'index' : dict like {index -> {column -> value}}
Abbreviations are allowed. `s` indicates `series` and `sp`
indicates `split`.
into : class, default dict
The collections.abc.Mapping subclass used for all Mappings
in the return value. Can be the actual class or an empty
instance of the mapping type you want. If you want a
collections.defaultdict, you must pass it initialized.
.. versionadded:: 0.21.0
Returns
-------
dict, list or collections.abc.Mapping
Return a collections.abc.Mapping object representing the DataFrame.
The resulting transformation depends on the `orient` parameter.
See Also
--------
DataFrame.from_dict: Create a DataFrame from a dictionary.
DataFrame.to_json: Convert a DataFrame to JSON format.
Examples
--------
>>> df = pd.DataFrame({'col1': [1, 2],
... 'col2': [0.5, 0.75]},
... index=['row1', 'row2'])
>>> df
col1 col2
row1 1 0.50
row2 2 0.75
>>> df.to_dict()
{'col1': {'row1': 1, 'row2': 2}, 'col2': {'row1': 0.5, 'row2': 0.75}}
You can specify the return orientation.
>>> df.to_dict('series')
{'col1': row1 1
row2 2
Name: col1, dtype: int64,
'col2': row1 0.50
row2 0.75
Name: col2, dtype: float64}
>>> df.to_dict('split')
{'index': ['row1', 'row2'], 'columns': ['col1', 'col2'],
'data': [[1, 0.5], [2, 0.75]]}
>>> df.to_dict('records')
[{'col1': 1, 'col2': 0.5}, {'col1': 2, 'col2': 0.75}]
>>> df.to_dict('index')
{'row1': {'col1': 1, 'col2': 0.5}, 'row2': {'col1': 2, 'col2': 0.75}}
You can also specify the mapping type.
>>> from collections import OrderedDict, defaultdict
>>> df.to_dict(into=OrderedDict)
OrderedDict([('col1', OrderedDict([('row1', 1), ('row2', 2)])),
('col2', OrderedDict([('row1', 0.5), ('row2', 0.75)]))])
If you want a `defaultdict`, you need to initialize it:
>>> dd = defaultdict(list)
>>> df.to_dict('records', into=dd)
[defaultdict(<class 'list'>, {'col1': 1, 'col2': 0.5}),
defaultdict(<class 'list'>, {'col1': 2, 'col2': 0.75})]
"""
if not self.columns.is_unique:
warnings.warn(
"DataFrame columns are not unique, some " "columns will be omitted.",
UserWarning,
stacklevel=2,
)
# GH16122
into_c = com.standardize_mapping(into)
if orient.lower().startswith("d"):
return into_c((k, v.to_dict(into)) for k, v in self.items())
elif orient.lower().startswith("l"):
return into_c((k, v.tolist()) for k, v in self.items())
elif orient.lower().startswith("sp"):
return into_c(
(
("index", self.index.tolist()),
("columns", self.columns.tolist()),
(
"data",
[
list(map(com.maybe_box_datetimelike, t))
for t in self.itertuples(index=False, name=None)
],
),
)
)
elif orient.lower().startswith("s"):
return into_c((k, com.maybe_box_datetimelike(v)) for k, v in self.items())
elif orient.lower().startswith("r"):
columns = self.columns.tolist()
rows = (
dict(zip(columns, row))
for row in self.itertuples(index=False, name=None)
)
return [
into_c((k, com.maybe_box_datetimelike(v)) for k, v in row.items())
for row in rows
]
elif orient.lower().startswith("i"):
if not self.index.is_unique:
raise ValueError("DataFrame index must be unique for orient='index'.")
return into_c(
(t[0], dict(zip(self.columns, t[1:])))
for t in self.itertuples(name=None)
)
else:
raise ValueError("orient '{o}' not understood".format(o=orient))
def to_gbq(
self,
destination_table,
project_id=None,
chunksize=None,
reauth=False,
if_exists="fail",
auth_local_webserver=False,
table_schema=None,
location=None,
progress_bar=True,
credentials=None,
verbose=None,
private_key=None,
):
"""
Write a DataFrame to a Google BigQuery table.
This function requires the `pandas-gbq package
<https://pandas-gbq.readthedocs.io>`__.
See the `How to authenticate with Google BigQuery
<https://pandas-gbq.readthedocs.io/en/latest/howto/authentication.html>`__
guide for authentication instructions.
Parameters
----------
destination_table : str
Name of table to be written, in the form ``dataset.tablename``.
project_id : str, optional
Google BigQuery Account project ID. Optional when available from
the environment.
chunksize : int, optional
Number of rows to be inserted in each chunk from the dataframe.
Set to ``None`` to load the whole dataframe at once.
reauth : bool, default False
Force Google BigQuery to re-authenticate the user. This is useful
if multiple accounts are used.
if_exists : str, default 'fail'
Behavior when the destination table exists. Value can be one of:
``'fail'``
If table exists, do nothing.
``'replace'``
If table exists, drop it, recreate it, and insert data.
``'append'``
If table exists, insert data. Create if does not exist.
auth_local_webserver : bool, default False
Use the `local webserver flow`_ instead of the `console flow`_
when getting user credentials.
.. _local webserver flow:
http://google-auth-oauthlib.readthedocs.io/en/latest/reference/google_auth_oauthlib.flow.html#google_auth_oauthlib.flow.InstalledAppFlow.run_local_server
.. _console flow:
http://google-auth-oauthlib.readthedocs.io/en/latest/reference/google_auth_oauthlib.flow.html#google_auth_oauthlib.flow.InstalledAppFlow.run_console
*New in version 0.2.0 of pandas-gbq*.
table_schema : list of dicts, optional
List of BigQuery table fields to which according DataFrame
columns conform to, e.g. ``[{'name': 'col1', 'type':
'STRING'},...]``. If schema is not provided, it will be
generated according to dtypes of DataFrame columns. See
BigQuery API documentation on available names of a field.
*New in version 0.3.1 of pandas-gbq*.
location : str, optional
Location where the load job should run. See the `BigQuery locations
documentation
<https://cloud.google.com/bigquery/docs/dataset-locations>`__ for a
list of available locations. The location must match that of the
target dataset.
*New in version 0.5.0 of pandas-gbq*.
progress_bar : bool, default True
Use the library `tqdm` to show the progress bar for the upload,
chunk by chunk.
*New in version 0.5.0 of pandas-gbq*.
credentials : google.auth.credentials.Credentials, optional
Credentials for accessing Google APIs. Use this parameter to
override default credentials, such as to use Compute Engine
:class:`google.auth.compute_engine.Credentials` or Service
Account :class:`google.oauth2.service_account.Credentials`
directly.
*New in version 0.8.0 of pandas-gbq*.
.. versionadded:: 0.24.0
verbose : bool, deprecated
Deprecated in pandas-gbq version 0.4.0. Use the `logging module
to adjust verbosity instead
<https://pandas-gbq.readthedocs.io/en/latest/intro.html#logging>`__.
private_key : str, deprecated
Deprecated in pandas-gbq version 0.8.0. Use the ``credentials``
parameter and
:func:`google.oauth2.service_account.Credentials.from_service_account_info`
or
:func:`google.oauth2.service_account.Credentials.from_service_account_file`
instead.
Service account private key in JSON format. Can be file path
or string contents. This is useful for remote server
authentication (eg. Jupyter/IPython notebook on remote host).
See Also
--------
pandas_gbq.to_gbq : This function in the pandas-gbq library.
read_gbq : Read a DataFrame from Google BigQuery.
"""
from pandas.io import gbq
gbq.to_gbq(
self,
destination_table,
project_id=project_id,
chunksize=chunksize,
reauth=reauth,
if_exists=if_exists,
auth_local_webserver=auth_local_webserver,
table_schema=table_schema,
location=location,
progress_bar=progress_bar,
credentials=credentials,
verbose=verbose,
private_key=private_key,
)
@classmethod
def from_records(
cls,
data,
index=None,
exclude=None,
columns=None,
coerce_float=False,
nrows=None,
):
"""
Convert structured or record ndarray to DataFrame.
Parameters
----------
data : ndarray (structured dtype), list of tuples, dict, or DataFrame
index : string, list of fields, array-like
Field of array to use as the index, alternately a specific set of
input labels to use
exclude : sequence, default None
Columns or fields to exclude
columns : sequence, default None
Column names to use. If the passed data do not have names
associated with them, this argument provides names for the
columns. Otherwise this argument indicates the order of the columns
in the result (any names not found in the data will become all-NA
columns)
coerce_float : boolean, default False
Attempt to convert values of non-string, non-numeric objects (like
decimal.Decimal) to floating point, useful for SQL result sets
nrows : int, default None
Number of rows to read if data is an iterator
Returns
-------
DataFrame
"""
# Make a copy of the input columns so we can modify it
if columns is not None:
columns = ensure_index(columns)
if is_iterator(data):
if nrows == 0:
return cls()
try:
first_row = next(data)
except StopIteration:
return cls(index=index, columns=columns)
dtype = None
if hasattr(first_row, "dtype") and first_row.dtype.names:
dtype = first_row.dtype
values = [first_row]
if nrows is None:
values += data
else:
values.extend(itertools.islice(data, nrows - 1))
if dtype is not None:
data = np.array(values, dtype=dtype)
else:
data = values
if isinstance(data, dict):
if columns is None:
columns = arr_columns = ensure_index(sorted(data))
arrays = [data[k] for k in columns]
else:
arrays = []
arr_columns = []
for k, v in data.items():
if k in columns:
arr_columns.append(k)
arrays.append(v)
arrays, arr_columns = reorder_arrays(arrays, arr_columns, columns)
elif isinstance(data, (np.ndarray, DataFrame)):
arrays, columns = to_arrays(data, columns)
if columns is not None:
columns = ensure_index(columns)
arr_columns = columns
else:
arrays, arr_columns = to_arrays(data, columns, coerce_float=coerce_float)
arr_columns = ensure_index(arr_columns)
if columns is not None:
columns = ensure_index(columns)
else:
columns = arr_columns
if exclude is None:
exclude = set()
else:
exclude = set(exclude)
result_index = None
if index is not None:
if isinstance(index, str) or not hasattr(index, "__iter__"):
i = columns.get_loc(index)
exclude.add(index)
if len(arrays) > 0:
result_index = Index(arrays[i], name=index)
else:
result_index = Index([], name=index)
else:
try:
index_data = [arrays[arr_columns.get_loc(field)] for field in index]
result_index = ensure_index_from_sequences(index_data, names=index)
exclude.update(index)
except Exception:
result_index = index
if any(exclude):
arr_exclude = [x for x in exclude if x in arr_columns]
to_remove = [arr_columns.get_loc(col) for col in arr_exclude]
arrays = [v for i, v in enumerate(arrays) if i not in to_remove]
arr_columns = arr_columns.drop(arr_exclude)
columns = columns.drop(exclude)
mgr = arrays_to_mgr(arrays, arr_columns, result_index, columns)
return cls(mgr)
def to_records(
self, index=True, convert_datetime64=None, column_dtypes=None, index_dtypes=None
):
"""
Convert DataFrame to a NumPy record array.
Index will be included as the first field of the record array if
requested.
Parameters
----------
index : bool, default True
Include index in resulting record array, stored in 'index'
field or using the index label, if set.
convert_datetime64 : bool, default None
.. deprecated:: 0.23.0
Whether to convert the index to datetime.datetime if it is a
DatetimeIndex.
column_dtypes : str, type, dict, default None
.. versionadded:: 0.24.0
If a string or type, the data type to store all columns. If
a dictionary, a mapping of column names and indices (zero-indexed)
to specific data types.
index_dtypes : str, type, dict, default None
.. versionadded:: 0.24.0
If a string or type, the data type to store all index levels. If
a dictionary, a mapping of index level names and indices
(zero-indexed) to specific data types.
This mapping is applied only if `index=True`.
Returns
-------
numpy.recarray
NumPy ndarray with the DataFrame labels as fields and each row
of the DataFrame as entries.
See Also
--------
DataFrame.from_records: Convert structured or record ndarray
to DataFrame.
numpy.recarray: An ndarray that allows field access using
attributes, analogous to typed columns in a
spreadsheet.
Examples
--------
>>> df = pd.DataFrame({'A': [1, 2], 'B': [0.5, 0.75]},
... index=['a', 'b'])
>>> df
A B
a 1 0.50
b 2 0.75
>>> df.to_records()
rec.array([('a', 1, 0.5 ), ('b', 2, 0.75)],
dtype=[('index', 'O'), ('A', '<i8'), ('B', '<f8')])
If the DataFrame index has no label then the recarray field name
is set to 'index'. If the index has a label then this is used as the
field name:
>>> df.index = df.index.rename("I")
>>> df.to_records()
rec.array([('a', 1, 0.5 ), ('b', 2, 0.75)],
dtype=[('I', 'O'), ('A', '<i8'), ('B', '<f8')])
The index can be excluded from the record array:
>>> df.to_records(index=False)
rec.array([(1, 0.5 ), (2, 0.75)],
dtype=[('A', '<i8'), ('B', '<f8')])
Data types can be specified for the columns:
>>> df.to_records(column_dtypes={"A": "int32"})
rec.array([('a', 1, 0.5 ), ('b', 2, 0.75)],
dtype=[('I', 'O'), ('A', '<i4'), ('B', '<f8')])
As well as for the index:
>>> df.to_records(index_dtypes="<S2")
rec.array([(b'a', 1, 0.5 ), (b'b', 2, 0.75)],
dtype=[('I', 'S2'), ('A', '<i8'), ('B', '<f8')])
>>> index_dtypes = "<S{}".format(df.index.str.len().max())
>>> df.to_records(index_dtypes=index_dtypes)
rec.array([(b'a', 1, 0.5 ), (b'b', 2, 0.75)],
dtype=[('I', 'S1'), ('A', '<i8'), ('B', '<f8')])
"""
if convert_datetime64 is not None:
warnings.warn(
"The 'convert_datetime64' parameter is "
"deprecated and will be removed in a future "
"version",
FutureWarning,
stacklevel=2,
)
if index:
if is_datetime64_any_dtype(self.index) and convert_datetime64:
ix_vals = [self.index.to_pydatetime()]
else:
if isinstance(self.index, MultiIndex):
# array of tuples to numpy cols. copy copy copy
ix_vals = list(map(np.array, zip(*self.index.values)))
else:
ix_vals = [self.index.values]
arrays = ix_vals + [self[c]._internal_get_values() for c in self.columns]
count = 0
index_names = list(self.index.names)
if isinstance(self.index, MultiIndex):
for i, n in enumerate(index_names):
if n is None:
index_names[i] = "level_%d" % count
count += 1
elif index_names[0] is None:
index_names = ["index"]
names = [str(name) for name in itertools.chain(index_names, self.columns)]
else:
arrays = [self[c]._internal_get_values() for c in self.columns]
names = [str(c) for c in self.columns]
index_names = []
index_len = len(index_names)
formats = []
for i, v in enumerate(arrays):
index = i
# When the names and arrays are collected, we
# first collect those in the DataFrame's index,
# followed by those in its columns.
#
# Thus, the total length of the array is:
# len(index_names) + len(DataFrame.columns).
#
# This check allows us to see whether we are
# handling a name / array in the index or column.
if index < index_len:
dtype_mapping = index_dtypes
name = index_names[index]
else:
index -= index_len
dtype_mapping = column_dtypes
name = self.columns[index]
# We have a dictionary, so we get the data type
# associated with the index or column (which can
# be denoted by its name in the DataFrame or its
# position in DataFrame's array of indices or
# columns, whichever is applicable.
if is_dict_like(dtype_mapping):
if name in dtype_mapping:
dtype_mapping = dtype_mapping[name]
elif index in dtype_mapping:
dtype_mapping = dtype_mapping[index]
else:
dtype_mapping = None
# If no mapping can be found, use the array's
# dtype attribute for formatting.
#
# A valid dtype must either be a type or
# string naming a type.
if dtype_mapping is None:
formats.append(v.dtype)
elif isinstance(dtype_mapping, (type, np.dtype, str)):
formats.append(dtype_mapping)
else:
element = "row" if i < index_len else "column"
msg = (
"Invalid dtype {dtype} specified for " "{element} {name}"
).format(dtype=dtype_mapping, element=element, name=name)
raise ValueError(msg)
return np.rec.fromarrays(arrays, dtype={"names": names, "formats": formats})
@classmethod
def from_items(cls, items, columns=None, orient="columns"):
"""
Construct a DataFrame from a list of tuples.
.. deprecated:: 0.23.0
`from_items` is deprecated and will be removed in a future version.
Use :meth:`DataFrame.from_dict(dict(items)) <DataFrame.from_dict>`
instead.
:meth:`DataFrame.from_dict(OrderedDict(items)) <DataFrame.from_dict>`
may be used to preserve the key order.
Convert (key, value) pairs to DataFrame. The keys will be the axis
index (usually the columns, but depends on the specified
orientation). The values should be arrays or Series.
Parameters
----------
items : sequence of (key, value) pairs
Values should be arrays or Series.
columns : sequence of column labels, optional
Must be passed if orient='index'.
orient : {'columns', 'index'}, default 'columns'
The "orientation" of the data. If the keys of the
input correspond to column labels, pass 'columns'
(default). Otherwise if the keys correspond to the index,
pass 'index'.
Returns
-------
DataFrame
"""
warnings.warn(
"from_items is deprecated. Please use "
"DataFrame.from_dict(dict(items), ...) instead. "
"DataFrame.from_dict(OrderedDict(items)) may be used to "
"preserve the key order.",
FutureWarning,
stacklevel=2,
)
keys, values = zip(*items)
if orient == "columns":
if columns is not None:
columns = ensure_index(columns)
idict = dict(items)
if len(idict) < len(items):
if not columns.equals(ensure_index(keys)):
raise ValueError(
"With non-unique item names, passed "
"columns must be identical"
)
arrays = values
else:
arrays = [idict[k] for k in columns if k in idict]
else:
columns = ensure_index(keys)
arrays = values
# GH 17312
# Provide more informative error msg when scalar values passed
try:
return cls._from_arrays(arrays, columns, None)
except ValueError:
if not is_nested_list_like(values):
raise ValueError(
"The value in each (key, value) pair "
"must be an array, Series, or dict"
)
elif orient == "index":
if columns is None:
raise TypeError("Must pass columns with orient='index'")
keys = ensure_index(keys)
# GH 17312
# Provide more informative error msg when scalar values passed
try:
arr = np.array(values, dtype=object).T
data = [lib.maybe_convert_objects(v) for v in arr]
return cls._from_arrays(data, columns, keys)
except TypeError:
if not is_nested_list_like(values):
raise ValueError(
"The value in each (key, value) pair "
"must be an array, Series, or dict"
)
else: # pragma: no cover
raise ValueError("'orient' must be either 'columns' or 'index'")
@classmethod
def _from_arrays(cls, arrays, columns, index, dtype=None):
mgr = arrays_to_mgr(arrays, columns, index, columns, dtype=dtype)
return cls(mgr)
def to_sparse(self, fill_value=None, kind="block"):
"""
Convert to SparseDataFrame.
.. deprecated:: 0.25.0
Implement the sparse version of the DataFrame meaning that any data
matching a specific value it's omitted in the representation.
The sparse DataFrame allows for a more efficient storage.
Parameters
----------
fill_value : float, default None
The specific value that should be omitted in the representation.
kind : {'block', 'integer'}, default 'block'
The kind of the SparseIndex tracking where data is not equal to
the fill value:
- 'block' tracks only the locations and sizes of blocks of data.
- 'integer' keeps an array with all the locations of the data.
In most cases 'block' is recommended, since it's more memory
efficient.
Returns
-------
SparseDataFrame
The sparse representation of the DataFrame.
See Also
--------
DataFrame.to_dense :
Converts the DataFrame back to the its dense form.
Examples
--------
>>> df = pd.DataFrame([(np.nan, np.nan),
... (1., np.nan),
... (np.nan, 1.)])
>>> df
0 1
0 NaN NaN
1 1.0 NaN
2 NaN 1.0
>>> type(df)
<class 'pandas.core.frame.DataFrame'>
>>> sdf = df.to_sparse() # doctest: +SKIP
>>> sdf # doctest: +SKIP
0 1
0 NaN NaN
1 1.0 NaN
2 NaN 1.0
>>> type(sdf) # doctest: +SKIP
<class 'pandas.core.sparse.frame.SparseDataFrame'>
"""
warnings.warn(
"DataFrame.to_sparse is deprecated and will be removed "
"in a future version",
FutureWarning,
stacklevel=2,
)
from pandas.core.sparse.api import SparseDataFrame
with warnings.catch_warnings():
warnings.filterwarnings("ignore", message="SparseDataFrame")
return SparseDataFrame(
self._series,
index=self.index,
columns=self.columns,
default_kind=kind,
default_fill_value=fill_value,
)
@deprecate_kwarg(old_arg_name="encoding", new_arg_name=None)
def to_stata(
self,
fname,
convert_dates=None,
write_index=True,
encoding="latin-1",
byteorder=None,
time_stamp=None,
data_label=None,
variable_labels=None,
version=114,
convert_strl=None,
):
"""
Export DataFrame object to Stata dta format.
Writes the DataFrame to a Stata dataset file.
"dta" files contain a Stata dataset.
Parameters
----------
fname : str, buffer or path object
String, path object (pathlib.Path or py._path.local.LocalPath) or
object implementing a binary write() function. If using a buffer
then the buffer will not be automatically closed after the file
data has been written.
convert_dates : dict
Dictionary mapping columns containing datetime types to stata
internal format to use when writing the dates. Options are 'tc',
'td', 'tm', 'tw', 'th', 'tq', 'ty'. Column can be either an integer
or a name. Datetime columns that do not have a conversion type
specified will be converted to 'tc'. Raises NotImplementedError if
a datetime column has timezone information.
write_index : bool
Write the index to Stata dataset.
encoding : str
Default is latin-1. Unicode is not supported.
byteorder : str
Can be ">", "<", "little", or "big". default is `sys.byteorder`.
time_stamp : datetime
A datetime to use as file creation date. Default is the current
time.
data_label : str, optional
A label for the data set. Must be 80 characters or smaller.
variable_labels : dict
Dictionary containing columns as keys and variable labels as
values. Each label must be 80 characters or smaller.
version : {114, 117}, default 114
Version to use in the output dta file. Version 114 can be used
read by Stata 10 and later. Version 117 can be read by Stata 13
or later. Version 114 limits string variables to 244 characters or
fewer while 117 allows strings with lengths up to 2,000,000
characters.
.. versionadded:: 0.23.0
convert_strl : list, optional
List of column names to convert to string columns to Stata StrL
format. Only available if version is 117. Storing strings in the
StrL format can produce smaller dta files if strings have more than
8 characters and values are repeated.
.. versionadded:: 0.23.0
Raises
------
NotImplementedError
* If datetimes contain timezone information
* Column dtype is not representable in Stata
ValueError
* Columns listed in convert_dates are neither datetime64[ns]
or datetime.datetime
* Column listed in convert_dates is not in DataFrame
* Categorical label contains more than 32,000 characters
See Also
--------
read_stata : Import Stata data files.
io.stata.StataWriter : Low-level writer for Stata data files.
io.stata.StataWriter117 : Low-level writer for version 117 files.
Examples
--------
>>> df = pd.DataFrame({'animal': ['falcon', 'parrot', 'falcon',
... 'parrot'],
... 'speed': [350, 18, 361, 15]})
>>> df.to_stata('animals.dta') # doctest: +SKIP
"""
kwargs = {}
if version not in (114, 117):
raise ValueError("Only formats 114 and 117 supported.")
if version == 114:
if convert_strl is not None:
raise ValueError(
"strl support is only available when using " "format 117"
)
from pandas.io.stata import StataWriter as statawriter
else:
from pandas.io.stata import StataWriter117 as statawriter
kwargs["convert_strl"] = convert_strl
writer = statawriter(
fname,
self,
convert_dates=convert_dates,
byteorder=byteorder,
time_stamp=time_stamp,
data_label=data_label,
write_index=write_index,
variable_labels=variable_labels,
**kwargs
)
writer.write_file()
def to_feather(self, fname):
"""
Write out the binary feather-format for DataFrames.
.. versionadded:: 0.20.0
Parameters
----------
fname : str
string file path
"""
from pandas.io.feather_format import to_feather
to_feather(self, fname)
def to_parquet(
self,
fname,
engine="auto",
compression="snappy",
index=None,
partition_cols=None,
**kwargs
):
"""
Write a DataFrame to the binary parquet format.
.. versionadded:: 0.21.0
This function writes the dataframe as a `parquet file
<https://parquet.apache.org/>`_. You can choose different parquet
backends, and have the option of compression. See
:ref:`the user guide <io.parquet>` for more details.
Parameters
----------
fname : str
File path or Root Directory path. Will be used as Root Directory
path while writing a partitioned dataset.
.. versionchanged:: 0.24.0
engine : {'auto', 'pyarrow', 'fastparquet'}, default 'auto'
Parquet library to use. If 'auto', then the option
``io.parquet.engine`` is used. The default ``io.parquet.engine``
behavior is to try 'pyarrow', falling back to 'fastparquet' if
'pyarrow' is unavailable.
compression : {'snappy', 'gzip', 'brotli', None}, default 'snappy'
Name of the compression to use. Use ``None`` for no compression.
index : bool, default None
If ``True``, include the dataframe's index(es) in the file output.
If ``False``, they will not be written to the file. If ``None``,
the behavior depends on the chosen engine.
.. versionadded:: 0.24.0
partition_cols : list, optional, default None
Column names by which to partition the dataset
Columns are partitioned in the order they are given
.. versionadded:: 0.24.0
**kwargs
Additional arguments passed to the parquet library. See
:ref:`pandas io <io.parquet>` for more details.
See Also
--------
read_parquet : Read a parquet file.
DataFrame.to_csv : Write a csv file.
DataFrame.to_sql : Write to a sql table.
DataFrame.to_hdf : Write to hdf.
Notes
-----
This function requires either the `fastparquet
<https://pypi.org/project/fastparquet>`_ or `pyarrow
<https://arrow.apache.org/docs/python/>`_ library.
Examples
--------
>>> df = pd.DataFrame(data={'col1': [1, 2], 'col2': [3, 4]})
>>> df.to_parquet('df.parquet.gzip',
... compression='gzip') # doctest: +SKIP
>>> pd.read_parquet('df.parquet.gzip') # doctest: +SKIP
col1 col2
0 1 3
1 2 4
"""
from pandas.io.parquet import to_parquet
to_parquet(
self,
fname,
engine,
compression=compression,
index=index,
partition_cols=partition_cols,
**kwargs
)
@Substitution(
header="Whether to print column labels, default True",
col_space_type="str or int",
col_space="The minimum width of each column in CSS length "
"units. An int is assumed to be px units.\n\n"
" .. versionadded:: 0.25.0\n"
" Ability to use str",
)
@Substitution(shared_params=fmt.common_docstring, returns=fmt.return_docstring)
def to_html(
self,
buf=None,
columns=None,
col_space=None,
header=True,
index=True,
na_rep="NaN",
formatters=None,
float_format=None,
sparsify=None,
index_names=True,
justify=None,
max_rows=None,
max_cols=None,
show_dimensions=False,
decimal=".",
bold_rows=True,
classes=None,
escape=True,
notebook=False,
border=None,
table_id=None,
render_links=False,
):
"""
Render a DataFrame as an HTML table.
%(shared_params)s
bold_rows : bool, default True
Make the row labels bold in the output.
classes : str or list or tuple, default None
CSS class(es) to apply to the resulting html table.
escape : bool, default True
Convert the characters <, >, and & to HTML-safe sequences.
notebook : {True, False}, default False
Whether the generated HTML is for IPython Notebook.
border : int
A ``border=border`` attribute is included in the opening
`<table>` tag. Default ``pd.options.display.html.border``.
table_id : str, optional
A css id is included in the opening `<table>` tag if specified.
.. versionadded:: 0.23.0
render_links : bool, default False
Convert URLs to HTML links.
.. versionadded:: 0.24.0
%(returns)s
See Also
--------
to_string : Convert DataFrame to a string.
"""
if justify is not None and justify not in fmt._VALID_JUSTIFY_PARAMETERS:
raise ValueError("Invalid value for justify parameter")
formatter = fmt.DataFrameFormatter(
self,
buf=buf,
columns=columns,
col_space=col_space,
na_rep=na_rep,
formatters=formatters,
float_format=float_format,
sparsify=sparsify,
justify=justify,
index_names=index_names,
header=header,
index=index,
bold_rows=bold_rows,
escape=escape,
max_rows=max_rows,
max_cols=max_cols,
show_dimensions=show_dimensions,
decimal=decimal,
table_id=table_id,
render_links=render_links,
)
# TODO: a generic formatter wld b in DataFrameFormatter
formatter.to_html(classes=classes, notebook=notebook, border=border)
if buf is None:
return formatter.buf.getvalue()
# ----------------------------------------------------------------------
def info(
self, verbose=None, buf=None, max_cols=None, memory_usage=None, null_counts=None
):
"""
Print a concise summary of a DataFrame.
This method prints information about a DataFrame including
the index dtype and column dtypes, non-null values and memory usage.
Parameters
----------
verbose : bool, optional
Whether to print the full summary. By default, the setting in
``pandas.options.display.max_info_columns`` is followed.
buf : writable buffer, defaults to sys.stdout
Where to send the output. By default, the output is printed to
sys.stdout. Pass a writable buffer if you need to further process
the output.
max_cols : int, optional
When to switch from the verbose to the truncated output. If the
DataFrame has more than `max_cols` columns, the truncated output
is used. By default, the setting in
``pandas.options.display.max_info_columns`` is used.
memory_usage : bool, str, optional
Specifies whether total memory usage of the DataFrame
elements (including the index) should be displayed. By default,
this follows the ``pandas.options.display.memory_usage`` setting.
True always show memory usage. False never shows memory usage.
A value of 'deep' is equivalent to "True with deep introspection".
Memory usage is shown in human-readable units (base-2
representation). Without deep introspection a memory estimation is
made based in column dtype and number of rows assuming values
consume the same memory amount for corresponding dtypes. With deep
memory introspection, a real memory usage calculation is performed
at the cost of computational resources.
null_counts : bool, optional
Whether to show the non-null counts. By default, this is shown
only if the frame is smaller than
``pandas.options.display.max_info_rows`` and
``pandas.options.display.max_info_columns``. A value of True always
shows the counts, and False never shows the counts.
Returns
-------
None
This method prints a summary of a DataFrame and returns None.
See Also
--------
DataFrame.describe: Generate descriptive statistics of DataFrame
columns.
DataFrame.memory_usage: Memory usage of DataFrame columns.
Examples
--------
>>> int_values = [1, 2, 3, 4, 5]
>>> text_values = ['alpha', 'beta', 'gamma', 'delta', 'epsilon']
>>> float_values = [0.0, 0.25, 0.5, 0.75, 1.0]
>>> df = pd.DataFrame({"int_col": int_values, "text_col": text_values,
... "float_col": float_values})
>>> df
int_col text_col float_col
0 1 alpha 0.00
1 2 beta 0.25
2 3 gamma 0.50
3 4 delta 0.75
4 5 epsilon 1.00
Prints information of all columns:
>>> df.info(verbose=True)
<class 'pandas.core.frame.DataFrame'>
RangeIndex: 5 entries, 0 to 4
Data columns (total 3 columns):
int_col 5 non-null int64
text_col 5 non-null object
float_col 5 non-null float64
dtypes: float64(1), int64(1), object(1)
memory usage: 248.0+ bytes
Prints a summary of columns count and its dtypes but not per column
information:
>>> df.info(verbose=False)
<class 'pandas.core.frame.DataFrame'>
RangeIndex: 5 entries, 0 to 4
Columns: 3 entries, int_col to float_col
dtypes: float64(1), int64(1), object(1)
memory usage: 248.0+ bytes
Pipe output of DataFrame.info to buffer instead of sys.stdout, get
buffer content and writes to a text file:
>>> import io
>>> buffer = io.StringIO()
>>> df.info(buf=buffer)
>>> s = buffer.getvalue()
>>> with open("df_info.txt", "w",
... encoding="utf-8") as f: # doctest: +SKIP
... f.write(s)
260
The `memory_usage` parameter allows deep introspection mode, specially
useful for big DataFrames and fine-tune memory optimization:
>>> random_strings_array = np.random.choice(['a', 'b', 'c'], 10 ** 6)
>>> df = pd.DataFrame({
... 'column_1': np.random.choice(['a', 'b', 'c'], 10 ** 6),
... 'column_2': np.random.choice(['a', 'b', 'c'], 10 ** 6),
... 'column_3': np.random.choice(['a', 'b', 'c'], 10 ** 6)
... })
>>> df.info()
<class 'pandas.core.frame.DataFrame'>
RangeIndex: 1000000 entries, 0 to 999999
Data columns (total 3 columns):
column_1 1000000 non-null object
column_2 1000000 non-null object
column_3 1000000 non-null object
dtypes: object(3)
memory usage: 22.9+ MB
>>> df.info(memory_usage='deep')
<class 'pandas.core.frame.DataFrame'>
RangeIndex: 1000000 entries, 0 to 999999
Data columns (total 3 columns):
column_1 1000000 non-null object
column_2 1000000 non-null object
column_3 1000000 non-null object
dtypes: object(3)
memory usage: 188.8 MB
"""
if buf is None: # pragma: no cover
buf = sys.stdout
lines = []
lines.append(str(type(self)))
lines.append(self.index._summary())
if len(self.columns) == 0:
lines.append("Empty {name}".format(name=type(self).__name__))
fmt.buffer_put_lines(buf, lines)
return
cols = self.columns
# hack
if max_cols is None:
max_cols = get_option("display.max_info_columns", len(self.columns) + 1)
max_rows = get_option("display.max_info_rows", len(self) + 1)
if null_counts is None:
show_counts = (len(self.columns) <= max_cols) and (len(self) < max_rows)
else:
show_counts = null_counts
exceeds_info_cols = len(self.columns) > max_cols
def _verbose_repr():
lines.append("Data columns (total %d columns):" % len(self.columns))
space = max(len(pprint_thing(k)) for k in self.columns) + 4
counts = None
tmpl = "{count}{dtype}"
if show_counts:
counts = self.count()
if len(cols) != len(counts): # pragma: no cover
raise AssertionError(
"Columns must equal counts "
"({cols:d} != {counts:d})".format(
cols=len(cols), counts=len(counts)
)
)
tmpl = "{count} non-null {dtype}"
dtypes = self.dtypes
for i, col in enumerate(self.columns):
dtype = dtypes.iloc[i]
col = pprint_thing(col)
count = ""
if show_counts:
count = counts.iloc[i]
lines.append(
_put_str(col, space) + tmpl.format(count=count, dtype=dtype)
)
def _non_verbose_repr():
lines.append(self.columns._summary(name="Columns"))
def _sizeof_fmt(num, size_qualifier):
# returns size in human readable format
for x in ["bytes", "KB", "MB", "GB", "TB"]:
if num < 1024.0:
return "{num:3.1f}{size_q} " "{x}".format(
num=num, size_q=size_qualifier, x=x
)
num /= 1024.0
return "{num:3.1f}{size_q} {pb}".format(
num=num, size_q=size_qualifier, pb="PB"
)
if verbose:
_verbose_repr()
elif verbose is False: # specifically set to False, not nesc None
_non_verbose_repr()
else:
if exceeds_info_cols:
_non_verbose_repr()
else:
_verbose_repr()
counts = self._data.get_dtype_counts()
dtypes = ["{k}({kk:d})".format(k=k[0], kk=k[1]) for k in sorted(counts.items())]
lines.append("dtypes: {types}".format(types=", ".join(dtypes)))
if memory_usage is None:
memory_usage = get_option("display.memory_usage")
if memory_usage:
# append memory usage of df to display
size_qualifier = ""
if memory_usage == "deep":
deep = True
else:
# size_qualifier is just a best effort; not guaranteed to catch
# all cases (e.g., it misses categorical data even with object
# categories)
deep = False
if "object" in counts or self.index._is_memory_usage_qualified():
size_qualifier = "+"
mem_usage = self.memory_usage(index=True, deep=deep).sum()
lines.append(
"memory usage: {mem}\n".format(
mem=_sizeof_fmt(mem_usage, size_qualifier)
)
)
fmt.buffer_put_lines(buf, lines)
def memory_usage(self, index=True, deep=False):
"""
Return the memory usage of each column in bytes.
The memory usage can optionally include the contribution of
the index and elements of `object` dtype.
This value is displayed in `DataFrame.info` by default. This can be
suppressed by setting ``pandas.options.display.memory_usage`` to False.
Parameters
----------
index : bool, default True
Specifies whether to include the memory usage of the DataFrame's
index in returned Series. If ``index=True``, the memory usage of
the index is the first item in the output.
deep : bool, default False
If True, introspect the data deeply by interrogating
`object` dtypes for system-level memory consumption, and include
it in the returned values.
Returns
-------
Series
A Series whose index is the original column names and whose values
is the memory usage of each column in bytes.
See Also
--------
numpy.ndarray.nbytes : Total bytes consumed by the elements of an
ndarray.
Series.memory_usage : Bytes consumed by a Series.
Categorical : Memory-efficient array for string values with
many repeated values.
DataFrame.info : Concise summary of a DataFrame.
Examples
--------
>>> dtypes = ['int64', 'float64', 'complex128', 'object', 'bool']
>>> data = dict([(t, np.ones(shape=5000).astype(t))
... for t in dtypes])
>>> df = pd.DataFrame(data)
>>> df.head()
int64 float64 complex128 object bool
0 1 1.0 1.0+0.0j 1 True
1 1 1.0 1.0+0.0j 1 True
2 1 1.0 1.0+0.0j 1 True
3 1 1.0 1.0+0.0j 1 True
4 1 1.0 1.0+0.0j 1 True
>>> df.memory_usage()
Index 128
int64 40000
float64 40000
complex128 80000
object 40000
bool 5000
dtype: int64
>>> df.memory_usage(index=False)
int64 40000
float64 40000
complex128 80000
object 40000
bool 5000
dtype: int64
The memory footprint of `object` dtype columns is ignored by default:
>>> df.memory_usage(deep=True)
Index 128
int64 40000
float64 40000
complex128 80000
object 160000
bool 5000
dtype: int64
Use a Categorical for efficient storage of an object-dtype column with
many repeated values.
>>> df['object'].astype('category').memory_usage(deep=True)
5216
"""
result = Series(
[c.memory_usage(index=False, deep=deep) for col, c in self.items()],
index=self.columns,
)
if index:
result = Series(self.index.memory_usage(deep=deep), index=["Index"]).append(
result
)
return result
def transpose(self, *args, **kwargs):
"""
Transpose index and columns.
Reflect the DataFrame over its main diagonal by writing rows as columns
and vice-versa. The property :attr:`.T` is an accessor to the method
:meth:`transpose`.
Parameters
----------
copy : bool, default False
If True, the underlying data is copied. Otherwise (default), no
copy is made if possible.
*args, **kwargs
Additional keywords have no effect but might be accepted for
compatibility with numpy.
Returns
-------
DataFrame
The transposed DataFrame.
See Also
--------
numpy.transpose : Permute the dimensions of a given array.
Notes
-----
Transposing a DataFrame with mixed dtypes will result in a homogeneous
DataFrame with the `object` dtype. In such a case, a copy of the data
is always made.
Examples
--------
**Square DataFrame with homogeneous dtype**
>>> d1 = {'col1': [1, 2], 'col2': [3, 4]}
>>> df1 = pd.DataFrame(data=d1)
>>> df1
col1 col2
0 1 3
1 2 4
>>> df1_transposed = df1.T # or df1.transpose()
>>> df1_transposed
0 1
col1 1 2
col2 3 4
When the dtype is homogeneous in the original DataFrame, we get a
transposed DataFrame with the same dtype:
>>> df1.dtypes
col1 int64
col2 int64
dtype: object
>>> df1_transposed.dtypes
0 int64
1 int64
dtype: object
**Non-square DataFrame with mixed dtypes**
>>> d2 = {'name': ['Alice', 'Bob'],
... 'score': [9.5, 8],
... 'employed': [False, True],
... 'kids': [0, 0]}
>>> df2 = pd.DataFrame(data=d2)
>>> df2
name score employed kids
0 Alice 9.5 False 0
1 Bob 8.0 True 0
>>> df2_transposed = df2.T # or df2.transpose()
>>> df2_transposed
0 1
name Alice Bob
score 9.5 8
employed False True
kids 0 0
When the DataFrame has mixed dtypes, we get a transposed DataFrame with
the `object` dtype:
>>> df2.dtypes
name object
score float64
employed bool
kids int64
dtype: object
>>> df2_transposed.dtypes
0 object
1 object
dtype: object
"""
nv.validate_transpose(args, dict())
return super().transpose(1, 0, **kwargs)
T = property(transpose)
# ----------------------------------------------------------------------
# Picklability
# legacy pickle formats
def _unpickle_frame_compat(self, state): # pragma: no cover
if len(state) == 2: # pragma: no cover
series, idx = state
columns = sorted(series)
else:
series, cols, idx = state
columns = com._unpickle_array(cols)
index = com._unpickle_array(idx)
self._data = self._init_dict(series, index, columns, None)
def _unpickle_matrix_compat(self, state): # pragma: no cover
# old unpickling
(vals, idx, cols), object_state = state
index = com._unpickle_array(idx)
dm = DataFrame(vals, index=index, columns=com._unpickle_array(cols), copy=False)
if object_state is not None:
ovals, _, ocols = object_state
objects = DataFrame(
ovals, index=index, columns=com._unpickle_array(ocols), copy=False
)
dm = dm.join(objects)
self._data = dm._data
# ----------------------------------------------------------------------
# Getting and setting elements
def _get_value(self, index, col, takeable: bool = False):
"""
Quickly retrieve single value at passed column and index.
Parameters
----------
index : row label
col : column label
takeable : interpret the index/col as indexers, default False
Returns
-------
scalar
"""
if takeable:
series = self._iget_item_cache(col)
return com.maybe_box_datetimelike(series._values[index])
series = self._get_item_cache(col)
engine = self.index._engine
try:
return engine.get_value(series._values, index)
except KeyError:
# GH 20629
if self.index.nlevels > 1:
# partial indexing forbidden
raise
except (TypeError, ValueError):
pass
# we cannot handle direct indexing
# use positional
col = self.columns.get_loc(col)
index = self.index.get_loc(index)
return self._get_value(index, col, takeable=True)
def _set_value(self, index, col, value, takeable: bool = False):
"""
Put single value at passed column and index.
Parameters
----------
index : row label
col : column label
value : scalar
takeable : interpret the index/col as indexers, default False
Returns
-------
DataFrame
If label pair is contained, will be reference to calling DataFrame,
otherwise a new object.
"""
try:
if takeable is True:
series = self._iget_item_cache(col)
return series._set_value(index, value, takeable=True)
series = self._get_item_cache(col)
engine = self.index._engine
engine.set_value(series._values, index, value)
return self
except (KeyError, TypeError):
# set using a non-recursive method & reset the cache
if takeable:
self.iloc[index, col] = value
else:
self.loc[index, col] = value
self._item_cache.pop(col, None)
return self
def _ixs(self, i: int, axis: int = 0):
"""
Parameters
----------
i : int
axis : int
Notes
-----
If slice passed, the resulting data will be a view.
"""
# irow
if axis == 0:
label = self.index[i]
new_values = self._data.fast_xs(i)
if is_scalar(new_values):
return new_values
# if we are a copy, mark as such
copy = isinstance(new_values, np.ndarray) and new_values.base is None
result = self._constructor_sliced(
new_values,
index=self.columns,
name=self.index[i],
dtype=new_values.dtype,
)
result._set_is_copy(self, copy=copy)
return result
# icol
else:
label = self.columns[i]
# if the values returned are not the same length
# as the index (iow a not found value), iget returns
# a 0-len ndarray. This is effectively catching
# a numpy error (as numpy should really raise)
values = self._data.iget(i)
if len(self.index) and not len(values):
values = np.array([np.nan] * len(self.index), dtype=object)
result = self._box_col_values(values, label)
# this is a cached value, mark it so
result._set_as_cached(label, self)
return result
def __getitem__(self, key):
key = lib.item_from_zerodim(key)
key = com.apply_if_callable(key, self)
if is_hashable(key):
# shortcut if the key is in columns
if self.columns.is_unique and key in self.columns:
if self.columns.nlevels > 1:
return self._getitem_multilevel(key)
return self._get_item_cache(key)
# Do we have a slicer (on rows)?
indexer = convert_to_index_sliceable(self, key)
if indexer is not None:
return self._slice(indexer, axis=0)
# Do we have a (boolean) DataFrame?
if isinstance(key, DataFrame):
return self._getitem_frame(key)
# Do we have a (boolean) 1d indexer?
if com.is_bool_indexer(key):
return self._getitem_bool_array(key)
# We are left with two options: a single key, and a collection of keys,
# We interpret tuples as collections only for non-MultiIndex
is_single_key = isinstance(key, tuple) or not is_list_like(key)
if is_single_key:
if self.columns.nlevels > 1:
return self._getitem_multilevel(key)
indexer = self.columns.get_loc(key)
if is_integer(indexer):
indexer = [indexer]
else:
if is_iterator(key):
key = list(key)
indexer = self.loc._get_listlike_indexer(key, axis=1, raise_missing=True)[1]
# take() does not accept boolean indexers
if getattr(indexer, "dtype", None) == bool:
indexer = np.where(indexer)[0]
data = self.take(indexer, axis=1)
if is_single_key:
# What does looking for a single key in a non-unique index return?
# The behavior is inconsistent. It returns a Series, except when
# - the key itself is repeated (test on data.shape, #9519), or
# - we have a MultiIndex on columns (test on self.columns, #21309)
if data.shape[1] == 1 and not isinstance(self.columns, MultiIndex):
data = data[key]
return data
def _getitem_bool_array(self, key):
# also raises Exception if object array with NA values
# warning here just in case -- previously __setitem__ was
# reindexing but __getitem__ was not; it seems more reasonable to
# go with the __setitem__ behavior since that is more consistent
# with all other indexing behavior
if isinstance(key, Series) and not key.index.equals(self.index):
warnings.warn(
"Boolean Series key will be reindexed to match " "DataFrame index.",
UserWarning,
stacklevel=3,
)
elif len(key) != len(self.index):
raise ValueError(
"Item wrong length %d instead of %d." % (len(key), len(self.index))
)
# check_bool_indexer will throw exception if Series key cannot
# be reindexed to match DataFrame rows
key = check_bool_indexer(self.index, key)
indexer = key.nonzero()[0]
return self.take(indexer, axis=0)
def _getitem_multilevel(self, key):
loc = self.columns.get_loc(key)
if isinstance(loc, (slice, Series, np.ndarray, Index)):
new_columns = self.columns[loc]
result_columns = maybe_droplevels(new_columns, key)
if self._is_mixed_type:
result = self.reindex(columns=new_columns)
result.columns = result_columns
else:
new_values = self.values[:, loc]
result = self._constructor(
new_values, index=self.index, columns=result_columns
)
result = result.__finalize__(self)
# If there is only one column being returned, and its name is
# either an empty string, or a tuple with an empty string as its
# first element, then treat the empty string as a placeholder
# and return the column as if the user had provided that empty
# string in the key. If the result is a Series, exclude the
# implied empty string from its name.
if len(result.columns) == 1:
top = result.columns[0]
if isinstance(top, tuple):
top = top[0]
if top == "":
result = result[""]
if isinstance(result, Series):
result = self._constructor_sliced(
result, index=self.index, name=key
)
result._set_is_copy(self)
return result
else:
return self._get_item_cache(key)
def _getitem_frame(self, key):
if key.values.size and not is_bool_dtype(key.values):
raise ValueError("Must pass DataFrame with boolean values only")
return self.where(key)
def query(self, expr, inplace=False, **kwargs):
"""
Query the columns of a DataFrame with a boolean expression.
Parameters
----------
expr : str
The query string to evaluate. You can refer to variables
in the environment by prefixing them with an '@' character like
``@a + b``.
.. versionadded:: 0.25.0
You can refer to column names that contain spaces by surrounding
them in backticks.
For example, if one of your columns is called ``a a`` and you want
to sum it with ``b``, your query should be ```a a` + b``.
inplace : bool
Whether the query should modify the data in place or return
a modified copy.
**kwargs
See the documentation for :func:`eval` for complete details
on the keyword arguments accepted by :meth:`DataFrame.query`.
Returns
-------
DataFrame
DataFrame resulting from the provided query expression.
See Also
--------
eval : Evaluate a string describing operations on
DataFrame columns.
DataFrame.eval : Evaluate a string describing operations on
DataFrame columns.
Notes
-----
The result of the evaluation of this expression is first passed to
:attr:`DataFrame.loc` and if that fails because of a
multidimensional key (e.g., a DataFrame) then the result will be passed
to :meth:`DataFrame.__getitem__`.
This method uses the top-level :func:`eval` function to
evaluate the passed query.
The :meth:`~pandas.DataFrame.query` method uses a slightly
modified Python syntax by default. For example, the ``&`` and ``|``
(bitwise) operators have the precedence of their boolean cousins,
:keyword:`and` and :keyword:`or`. This *is* syntactically valid Python,
however the semantics are different.
You can change the semantics of the expression by passing the keyword
argument ``parser='python'``. This enforces the same semantics as
evaluation in Python space. Likewise, you can pass ``engine='python'``
to evaluate an expression using Python itself as a backend. This is not
recommended as it is inefficient compared to using ``numexpr`` as the
engine.
The :attr:`DataFrame.index` and
:attr:`DataFrame.columns` attributes of the
:class:`~pandas.DataFrame` instance are placed in the query namespace
by default, which allows you to treat both the index and columns of the
frame as a column in the frame.
The identifier ``index`` is used for the frame index; you can also
use the name of the index to identify it in a query. Please note that
Python keywords may not be used as identifiers.
For further details and examples see the ``query`` documentation in
:ref:`indexing <indexing.query>`.
Examples
--------
>>> df = pd.DataFrame({'A': range(1, 6),
... 'B': range(10, 0, -2),
... 'C C': range(10, 5, -1)})
>>> df
A B C C
0 1 10 10
1 2 8 9
2 3 6 8
3 4 4 7
4 5 2 6
>>> df.query('A > B')
A B C C
4 5 2 6
The previous expression is equivalent to
>>> df[df.A > df.B]
A B C C
4 5 2 6
For columns with spaces in their name, you can use backtick quoting.
>>> df.query('B == `C C`')
A B C C
0 1 10 10
The previous expression is equivalent to
>>> df[df.B == df['C C']]
A B C C
0 1 10 10
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not isinstance(expr, str):
msg = "expr must be a string to be evaluated, {0} given"
raise ValueError(msg.format(type(expr)))
kwargs["level"] = kwargs.pop("level", 0) + 1
kwargs["target"] = None
res = self.eval(expr, **kwargs)
try:
new_data = self.loc[res]
except ValueError:
# when res is multi-dimensional loc raises, but this is sometimes a
# valid query
new_data = self[res]
if inplace:
self._update_inplace(new_data)
else:
return new_data
def eval(self, expr, inplace=False, **kwargs):
"""
Evaluate a string describing operations on DataFrame columns.
Operates on columns only, not specific rows or elements. This allows
`eval` to run arbitrary code, which can make you vulnerable to code
injection if you pass user input to this function.
Parameters
----------
expr : str
The expression string to evaluate.
inplace : bool, default False
If the expression contains an assignment, whether to perform the
operation inplace and mutate the existing DataFrame. Otherwise,
a new DataFrame is returned.
kwargs : dict
See the documentation for :func:`eval` for complete details
on the keyword arguments accepted by
:meth:`~pandas.DataFrame.query`.
Returns
-------
ndarray, scalar, or pandas object
The result of the evaluation.
See Also
--------
DataFrame.query : Evaluates a boolean expression to query the columns
of a frame.
DataFrame.assign : Can evaluate an expression or function to create new
values for a column.
eval : Evaluate a Python expression as a string using various
backends.
Notes
-----
For more details see the API documentation for :func:`~eval`.
For detailed examples see :ref:`enhancing performance with eval
<enhancingperf.eval>`.
Examples
--------
>>> df = pd.DataFrame({'A': range(1, 6), 'B': range(10, 0, -2)})
>>> df
A B
0 1 10
1 2 8
2 3 6
3 4 4
4 5 2
>>> df.eval('A + B')
0 11
1 10
2 9
3 8
4 7
dtype: int64
Assignment is allowed though by default the original DataFrame is not
modified.
>>> df.eval('C = A + B')
A B C
0 1 10 11
1 2 8 10
2 3 6 9
3 4 4 8
4 5 2 7
>>> df
A B
0 1 10
1 2 8
2 3 6
3 4 4
4 5 2
Use ``inplace=True`` to modify the original DataFrame.
>>> df.eval('C = A + B', inplace=True)
>>> df
A B C
0 1 10 11
1 2 8 10
2 3 6 9
3 4 4 8
4 5 2 7
"""
from pandas.core.computation.eval import eval as _eval
inplace = validate_bool_kwarg(inplace, "inplace")
resolvers = kwargs.pop("resolvers", None)
kwargs["level"] = kwargs.pop("level", 0) + 1
if resolvers is None:
index_resolvers = self._get_index_resolvers()
column_resolvers = self._get_space_character_free_column_resolvers()
resolvers = column_resolvers, index_resolvers
if "target" not in kwargs:
kwargs["target"] = self
kwargs["resolvers"] = kwargs.get("resolvers", ()) + tuple(resolvers)
return _eval(expr, inplace=inplace, **kwargs)
def select_dtypes(self, include=None, exclude=None):
"""
Return a subset of the DataFrame's columns based on the column dtypes.
Parameters
----------
include, exclude : scalar or list-like
A selection of dtypes or strings to be included/excluded. At least
one of these parameters must be supplied.
Returns
-------
DataFrame
The subset of the frame including the dtypes in ``include`` and
excluding the dtypes in ``exclude``.
Raises
------
ValueError
* If both of ``include`` and ``exclude`` are empty
* If ``include`` and ``exclude`` have overlapping elements
* If any kind of string dtype is passed in.
Notes
-----
* To select all *numeric* types, use ``np.number`` or ``'number'``
* To select strings you must use the ``object`` dtype, but note that
this will return *all* object dtype columns
* See the `numpy dtype hierarchy
<http://docs.scipy.org/doc/numpy/reference/arrays.scalars.html>`__
* To select datetimes, use ``np.datetime64``, ``'datetime'`` or
``'datetime64'``
* To select timedeltas, use ``np.timedelta64``, ``'timedelta'`` or
``'timedelta64'``
* To select Pandas categorical dtypes, use ``'category'``
* To select Pandas datetimetz dtypes, use ``'datetimetz'`` (new in
0.20.0) or ``'datetime64[ns, tz]'``
Examples
--------
>>> df = pd.DataFrame({'a': [1, 2] * 3,
... 'b': [True, False] * 3,
... 'c': [1.0, 2.0] * 3})
>>> df
a b c
0 1 True 1.0
1 2 False 2.0
2 1 True 1.0
3 2 False 2.0
4 1 True 1.0
5 2 False 2.0
>>> df.select_dtypes(include='bool')
b
0 True
1 False
2 True
3 False
4 True
5 False
>>> df.select_dtypes(include=['float64'])
c
0 1.0
1 2.0
2 1.0
3 2.0
4 1.0
5 2.0
>>> df.select_dtypes(exclude=['int'])
b c
0 True 1.0
1 False 2.0
2 True 1.0
3 False 2.0
4 True 1.0
5 False 2.0
"""
def _get_info_slice(obj, indexer):
"""Slice the info axis of `obj` with `indexer`."""
if not hasattr(obj, "_info_axis_number"):
msg = "object of type {typ!r} has no info axis"
raise TypeError(msg.format(typ=type(obj).__name__))
slices = [slice(None)] * obj.ndim
slices[obj._info_axis_number] = indexer
return tuple(slices)
if not is_list_like(include):
include = (include,) if include is not None else ()
if not is_list_like(exclude):
exclude = (exclude,) if exclude is not None else ()
selection = tuple(map(frozenset, (include, exclude)))
if not any(selection):
raise ValueError("at least one of include or exclude must be " "nonempty")
# convert the myriad valid dtypes object to a single representation
include, exclude = map(
lambda x: frozenset(map(infer_dtype_from_object, x)), selection
)
for dtypes in (include, exclude):
invalidate_string_dtypes(dtypes)
# can't both include AND exclude!
if not include.isdisjoint(exclude):
raise ValueError(
"include and exclude overlap on {inc_ex}".format(
inc_ex=(include & exclude)
)
)
# empty include/exclude -> defaults to True
# three cases (we've already raised if both are empty)
# case 1: empty include, nonempty exclude
# we have True, True, ... True for include, same for exclude
# in the loop below we get the excluded
# and when we call '&' below we get only the excluded
# case 2: nonempty include, empty exclude
# same as case 1, but with include
# case 3: both nonempty
# the "union" of the logic of case 1 and case 2:
# we get the included and excluded, and return their logical and
include_these = Series(not bool(include), index=self.columns)
exclude_these = Series(not bool(exclude), index=self.columns)
def is_dtype_instance_mapper(idx, dtype):
return idx, functools.partial(issubclass, dtype.type)
for idx, f in itertools.starmap(
is_dtype_instance_mapper, enumerate(self.dtypes)
):
if include: # checks for the case of empty include or exclude
include_these.iloc[idx] = any(map(f, include))
if exclude:
exclude_these.iloc[idx] = not any(map(f, exclude))
dtype_indexer = include_these & exclude_these
return self.loc[_get_info_slice(self, dtype_indexer)]
def _box_item_values(self, key, values):
items = self.columns[self.columns.get_loc(key)]
if values.ndim == 2:
return self._constructor(values.T, columns=items, index=self.index)
else:
return self._box_col_values(values, items)
def _box_col_values(self, values, items):
"""
Provide boxed values for a column.
"""
klass = self._constructor_sliced
return klass(values, index=self.index, name=items, fastpath=True)
def __setitem__(self, key, value):
key = com.apply_if_callable(key, self)
# see if we can slice the rows
indexer = convert_to_index_sliceable(self, key)
if indexer is not None:
return self._setitem_slice(indexer, value)
if isinstance(key, DataFrame) or getattr(key, "ndim", None) == 2:
self._setitem_frame(key, value)
elif isinstance(key, (Series, np.ndarray, list, Index)):
self._setitem_array(key, value)
else:
# set column
self._set_item(key, value)
def _setitem_slice(self, key, value):
self._check_setitem_copy()
self.loc[key] = value
def _setitem_array(self, key, value):
# also raises Exception if object array with NA values
if com.is_bool_indexer(key):
if len(key) != len(self.index):
raise ValueError(
"Item wrong length %d instead of %d!" % (len(key), len(self.index))
)
key = check_bool_indexer(self.index, key)
indexer = key.nonzero()[0]
self._check_setitem_copy()
self.loc._setitem_with_indexer(indexer, value)
else:
if isinstance(value, DataFrame):
if len(value.columns) != len(key):
raise ValueError("Columns must be same length as key")
for k1, k2 in zip(key, value.columns):
self[k1] = value[k2]
else:
indexer = self.loc._get_listlike_indexer(
key, axis=1, raise_missing=False
)[1]
self._check_setitem_copy()
self.loc._setitem_with_indexer((slice(None), indexer), value)
def _setitem_frame(self, key, value):
# support boolean setting with DataFrame input, e.g.
# df[df > df2] = 0
if isinstance(key, np.ndarray):
if key.shape != self.shape:
raise ValueError("Array conditional must be same shape as self")
key = self._constructor(key, **self._construct_axes_dict())
if key.values.size and not is_bool_dtype(key.values):
raise TypeError(
"Must pass DataFrame or 2-d ndarray with boolean values only"
)
self._check_inplace_setting(value)
self._check_setitem_copy()
self._where(-key, value, inplace=True)
def _ensure_valid_index(self, value):
"""
Ensure that if we don't have an index, that we can create one from the
passed value.
"""
# GH5632, make sure that we are a Series convertible
if not len(self.index) and is_list_like(value):
try:
value = Series(value)
except (ValueError, NotImplementedError, TypeError):
raise ValueError(
"Cannot set a frame with no defined index "
"and a value that cannot be converted to a "
"Series"
)
self._data = self._data.reindex_axis(
value.index.copy(), axis=1, fill_value=np.nan
)
def _set_item(self, key, value):
"""
Add series to DataFrame in specified column.
If series is a numpy-array (not a Series/TimeSeries), it must be the
same length as the DataFrames index or an error will be thrown.
Series/TimeSeries will be conformed to the DataFrames index to
ensure homogeneity.
"""
self._ensure_valid_index(value)
value = self._sanitize_column(key, value)
NDFrame._set_item(self, key, value)
# check if we are modifying a copy
# try to set first as we want an invalid
# value exception to occur first
if len(self):
self._check_setitem_copy()
def insert(self, loc, column, value, allow_duplicates=False):
"""
Insert column into DataFrame at specified location.
Raises a ValueError if `column` is already contained in the DataFrame,
unless `allow_duplicates` is set to True.
Parameters
----------
loc : int
Insertion index. Must verify 0 <= loc <= len(columns)
column : string, number, or hashable object
label of the inserted column
value : int, Series, or array-like
allow_duplicates : bool, optional
"""
self._ensure_valid_index(value)
value = self._sanitize_column(column, value, broadcast=False)
self._data.insert(loc, column, value, allow_duplicates=allow_duplicates)
def assign(self, **kwargs):
r"""
Assign new columns to a DataFrame.
Returns a new object with all original columns in addition to new ones.
Existing columns that are re-assigned will be overwritten.
Parameters
----------
**kwargs : dict of {str: callable or Series}
The column names are keywords. If the values are
callable, they are computed on the DataFrame and
assigned to the new columns. The callable must not
change input DataFrame (though pandas doesn't check it).
If the values are not callable, (e.g. a Series, scalar, or array),
they are simply assigned.
Returns
-------
DataFrame
A new DataFrame with the new columns in addition to
all the existing columns.
Notes
-----
Assigning multiple columns within the same ``assign`` is possible.
For Python 3.6 and above, later items in '\*\*kwargs' may refer to
newly created or modified columns in 'df'; items are computed and
assigned into 'df' in order. For Python 3.5 and below, the order of
keyword arguments is not specified, you cannot refer to newly created
or modified columns. All items are computed first, and then assigned
in alphabetical order.
.. versionchanged :: 0.23.0
Keyword argument order is maintained for Python 3.6 and later.
Examples
--------
>>> df = pd.DataFrame({'temp_c': [17.0, 25.0]},
... index=['Portland', 'Berkeley'])
>>> df
temp_c
Portland 17.0
Berkeley 25.0
Where the value is a callable, evaluated on `df`:
>>> df.assign(temp_f=lambda x: x.temp_c * 9 / 5 + 32)
temp_c temp_f
Portland 17.0 62.6
Berkeley 25.0 77.0
Alternatively, the same behavior can be achieved by directly
referencing an existing Series or sequence:
>>> df.assign(temp_f=df['temp_c'] * 9 / 5 + 32)
temp_c temp_f
Portland 17.0 62.6
Berkeley 25.0 77.0
In Python 3.6+, you can create multiple columns within the same assign
where one of the columns depends on another one defined within the same
assign:
>>> df.assign(temp_f=lambda x: x['temp_c'] * 9 / 5 + 32,
... temp_k=lambda x: (x['temp_f'] + 459.67) * 5 / 9)
temp_c temp_f temp_k
Portland 17.0 62.6 290.15
Berkeley 25.0 77.0 298.15
"""
data = self.copy()
# >= 3.6 preserve order of kwargs
if PY36:
for k, v in kwargs.items():
data[k] = com.apply_if_callable(v, data)
else:
# <= 3.5: do all calculations first...
results = OrderedDict()
for k, v in kwargs.items():
results[k] = com.apply_if_callable(v, data)
# <= 3.5 and earlier
results = sorted(results.items())
# ... and then assign
for k, v in results:
data[k] = v
return data
def _sanitize_column(self, key, value, broadcast=True):
"""
Ensures new columns (which go into the BlockManager as new blocks) are
always copied and converted into an array.
Parameters
----------
key : object
value : scalar, Series, or array-like
broadcast : bool, default True
If ``key`` matches multiple duplicate column names in the
DataFrame, this parameter indicates whether ``value`` should be
tiled so that the returned array contains a (duplicated) column for
each occurrence of the key. If False, ``value`` will not be tiled.
Returns
-------
numpy.ndarray
"""
def reindexer(value):
# reindex if necessary
if value.index.equals(self.index) or not len(self.index):
value = value._values.copy()
else:
# GH 4107
try:
value = value.reindex(self.index)._values
except Exception as e:
# duplicate axis
if not value.index.is_unique:
raise e
# other
raise TypeError(
"incompatible index of inserted column " "with frame index"
)
return value
if isinstance(value, Series):
value = reindexer(value)
elif isinstance(value, DataFrame):
# align right-hand-side columns if self.columns
# is multi-index and self[key] is a sub-frame
if isinstance(self.columns, MultiIndex) and key in self.columns:
loc = self.columns.get_loc(key)
if isinstance(loc, (slice, Series, np.ndarray, Index)):
cols = maybe_droplevels(self.columns[loc], key)
if len(cols) and not cols.equals(value.columns):
value = value.reindex(cols, axis=1)
# now align rows
value = reindexer(value).T
elif isinstance(value, ExtensionArray):
# Explicitly copy here, instead of in sanitize_index,
# as sanitize_index won't copy an EA, even with copy=True
value = value.copy()
value = sanitize_index(value, self.index, copy=False)
elif isinstance(value, Index) or is_sequence(value):
# turn me into an ndarray
value = sanitize_index(value, self.index, copy=False)
if not isinstance(value, (np.ndarray, Index)):
if isinstance(value, list) and len(value) > 0:
value = maybe_convert_platform(value)
else:
value = com.asarray_tuplesafe(value)
elif value.ndim == 2:
value = value.copy().T
elif isinstance(value, Index):
value = value.copy(deep=True)
else:
value = value.copy()
# possibly infer to datetimelike
if is_object_dtype(value.dtype):
value = maybe_infer_to_datetimelike(value)
else:
# cast ignores pandas dtypes. so save the dtype first
infer_dtype, _ = infer_dtype_from_scalar(value, pandas_dtype=True)
# upcast
value = cast_scalar_to_array(len(self.index), value)
value = maybe_cast_to_datetime(value, infer_dtype)
# return internal types directly
if is_extension_type(value) or is_extension_array_dtype(value):
return value
# broadcast across multiple columns if necessary
if broadcast and key in self.columns and value.ndim == 1:
if not self.columns.is_unique or isinstance(self.columns, MultiIndex):
existing_piece = self[key]
if isinstance(existing_piece, DataFrame):
value = np.tile(value, (len(existing_piece.columns), 1))
return np.atleast_2d(np.asarray(value))
@property
def _series(self):
return {
item: Series(self._data.iget(idx), index=self.index, name=item)
for idx, item in enumerate(self.columns)
}
def lookup(self, row_labels, col_labels):
"""
Label-based "fancy indexing" function for DataFrame.
Given equal-length arrays of row and column labels, return an
array of the values corresponding to each (row, col) pair.
Parameters
----------
row_labels : sequence
The row labels to use for lookup
col_labels : sequence
The column labels to use for lookup
Returns
-------
numpy.ndarray
Notes
-----
Akin to::
result = [df.get_value(row, col)
for row, col in zip(row_labels, col_labels)]
Examples
--------
values : ndarray
The found values
"""
n = len(row_labels)
if n != len(col_labels):
raise ValueError("Row labels must have same size as column labels")
thresh = 1000
if not self._is_mixed_type or n > thresh:
values = self.values
ridx = self.index.get_indexer(row_labels)
cidx = self.columns.get_indexer(col_labels)
if (ridx == -1).any():
raise KeyError("One or more row labels was not found")
if (cidx == -1).any():
raise KeyError("One or more column labels was not found")
flat_index = ridx * len(self.columns) + cidx
result = values.flat[flat_index]
else:
result = np.empty(n, dtype="O")
for i, (r, c) in enumerate(zip(row_labels, col_labels)):
result[i] = self._get_value(r, c)
if is_object_dtype(result):
result = lib.maybe_convert_objects(result)
return result
# ----------------------------------------------------------------------
# Reindexing and alignment
def _reindex_axes(self, axes, level, limit, tolerance, method, fill_value, copy):
frame = self
columns = axes["columns"]
if columns is not None:
frame = frame._reindex_columns(
columns, method, copy, level, fill_value, limit, tolerance
)
index = axes["index"]
if index is not None:
frame = frame._reindex_index(
index, method, copy, level, fill_value, limit, tolerance
)
return frame
def _reindex_index(
self,
new_index,
method,
copy,
level,
fill_value=np.nan,
limit=None,
tolerance=None,
):
new_index, indexer = self.index.reindex(
new_index, method=method, level=level, limit=limit, tolerance=tolerance
)
return self._reindex_with_indexers(
{0: [new_index, indexer]},
copy=copy,
fill_value=fill_value,
allow_dups=False,
)
def _reindex_columns(
self,
new_columns,
method,
copy,
level,
fill_value=None,
limit=None,
tolerance=None,
):
new_columns, indexer = self.columns.reindex(
new_columns, method=method, level=level, limit=limit, tolerance=tolerance
)
return self._reindex_with_indexers(
{1: [new_columns, indexer]},
copy=copy,
fill_value=fill_value,
allow_dups=False,
)
def _reindex_multi(self, axes, copy, fill_value):
"""
We are guaranteed non-Nones in the axes.
"""
new_index, row_indexer = self.index.reindex(axes["index"])
new_columns, col_indexer = self.columns.reindex(axes["columns"])
if row_indexer is not None and col_indexer is not None:
indexer = row_indexer, col_indexer
new_values = algorithms.take_2d_multi(
self.values, indexer, fill_value=fill_value
)
return self._constructor(new_values, index=new_index, columns=new_columns)
else:
return self._reindex_with_indexers(
{0: [new_index, row_indexer], 1: [new_columns, col_indexer]},
copy=copy,
fill_value=fill_value,
)
@Appender(_shared_docs["align"] % _shared_doc_kwargs)
def align(
self,
other,
join="outer",
axis=None,
level=None,
copy=True,
fill_value=None,
method=None,
limit=None,
fill_axis=0,
broadcast_axis=None,
):
return super().align(
other,
join=join,
axis=axis,
level=level,
copy=copy,
fill_value=fill_value,
method=method,
limit=limit,
fill_axis=fill_axis,
broadcast_axis=broadcast_axis,
)
@Substitution(**_shared_doc_kwargs)
@Appender(NDFrame.reindex.__doc__)
@rewrite_axis_style_signature(
"labels",
[
("method", None),
("copy", True),
("level", None),
("fill_value", np.nan),
("limit", None),
("tolerance", None),
],
)
def reindex(self, *args, **kwargs):
axes = validate_axis_style_args(self, args, kwargs, "labels", "reindex")
kwargs.update(axes)
# Pop these, since the values are in `kwargs` under different names
kwargs.pop("axis", None)
kwargs.pop("labels", None)
return super().reindex(**kwargs)
def drop(
self,
labels=None,
axis=0,
index=None,
columns=None,
level=None,
inplace=False,
errors="raise",
):
"""
Drop specified labels from rows or columns.
Remove rows or columns by specifying label names and corresponding
axis, or by specifying directly index or column names. When using a
multi-index, labels on different levels can be removed by specifying
the level.
Parameters
----------
labels : single label or list-like
Index or column labels to drop.
axis : {0 or 'index', 1 or 'columns'}, default 0
Whether to drop labels from the index (0 or 'index') or
columns (1 or 'columns').
index : single label or list-like
Alternative to specifying axis (``labels, axis=0``
is equivalent to ``index=labels``).
.. versionadded:: 0.21.0
columns : single label or list-like
Alternative to specifying axis (``labels, axis=1``
is equivalent to ``columns=labels``).
.. versionadded:: 0.21.0
level : int or level name, optional
For MultiIndex, level from which the labels will be removed.
inplace : bool, default False
If True, do operation inplace and return None.
errors : {'ignore', 'raise'}, default 'raise'
If 'ignore', suppress error and only existing labels are
dropped.
Returns
-------
DataFrame
DataFrame without the removed index or column labels.
Raises
------
KeyError
If any of the labels is not found in the selected axis.
See Also
--------
DataFrame.loc : Label-location based indexer for selection by label.
DataFrame.dropna : Return DataFrame with labels on given axis omitted
where (all or any) data are missing.
DataFrame.drop_duplicates : Return DataFrame with duplicate rows
removed, optionally only considering certain columns.
Series.drop : Return Series with specified index labels removed.
Examples
--------
>>> df = pd.DataFrame(np.arange(12).reshape(3, 4),
... columns=['A', 'B', 'C', 'D'])
>>> df
A B C D
0 0 1 2 3
1 4 5 6 7
2 8 9 10 11
Drop columns
>>> df.drop(['B', 'C'], axis=1)
A D
0 0 3
1 4 7
2 8 11
>>> df.drop(columns=['B', 'C'])
A D
0 0 3
1 4 7
2 8 11
Drop a row by index
>>> df.drop([0, 1])
A B C D
2 8 9 10 11
Drop columns and/or rows of MultiIndex DataFrame
>>> midx = pd.MultiIndex(levels=[['lama', 'cow', 'falcon'],
... ['speed', 'weight', 'length']],
... codes=[[0, 0, 0, 1, 1, 1, 2, 2, 2],
... [0, 1, 2, 0, 1, 2, 0, 1, 2]])
>>> df = pd.DataFrame(index=midx, columns=['big', 'small'],
... data=[[45, 30], [200, 100], [1.5, 1], [30, 20],
... [250, 150], [1.5, 0.8], [320, 250],
... [1, 0.8], [0.3, 0.2]])
>>> df
big small
lama speed 45.0 30.0
weight 200.0 100.0
length 1.5 1.0
cow speed 30.0 20.0
weight 250.0 150.0
length 1.5 0.8
falcon speed 320.0 250.0
weight 1.0 0.8
length 0.3 0.2
>>> df.drop(index='cow', columns='small')
big
lama speed 45.0
weight 200.0
length 1.5
falcon speed 320.0
weight 1.0
length 0.3
>>> df.drop(index='length', level=1)
big small
lama speed 45.0 30.0
weight 200.0 100.0
cow speed 30.0 20.0
weight 250.0 150.0
falcon speed 320.0 250.0
weight 1.0 0.8
"""
return super().drop(
labels=labels,
axis=axis,
index=index,
columns=columns,
level=level,
inplace=inplace,
errors=errors,
)
@rewrite_axis_style_signature(
"mapper",
[("copy", True), ("inplace", False), ("level", None), ("errors", "ignore")],
)
def rename(self, *args, **kwargs):
"""
Alter axes labels.
Function / dict values must be unique (1-to-1). Labels not contained in
a dict / Series will be left as-is. Extra labels listed don't throw an
error.
See the :ref:`user guide <basics.rename>` for more.
Parameters
----------
mapper : dict-like or function
Dict-like or functions transformations to apply to
that axis' values. Use either ``mapper`` and ``axis`` to
specify the axis to target with ``mapper``, or ``index`` and
``columns``.
index : dict-like or function
Alternative to specifying axis (``mapper, axis=0``
is equivalent to ``index=mapper``).
columns : dict-like or function
Alternative to specifying axis (``mapper, axis=1``
is equivalent to ``columns=mapper``).
axis : int or str
Axis to target with ``mapper``. Can be either the axis name
('index', 'columns') or number (0, 1). The default is 'index'.
copy : bool, default True
Also copy underlying data.
inplace : bool, default False
Whether to return a new DataFrame. If True then value of copy is
ignored.
level : int or level name, default None
In case of a MultiIndex, only rename labels in the specified
level.
errors : {'ignore', 'raise'}, default 'ignore'
If 'raise', raise a `KeyError` when a dict-like `mapper`, `index`,
or `columns` contains labels that are not present in the Index
being transformed.
If 'ignore', existing keys will be renamed and extra keys will be
ignored.
Returns
-------
DataFrame
DataFrame with the renamed axis labels.
Raises
------
KeyError
If any of the labels is not found in the selected axis and
"errors='raise'".
See Also
--------
DataFrame.rename_axis : Set the name of the axis.
Examples
--------
``DataFrame.rename`` supports two calling conventions
* ``(index=index_mapper, columns=columns_mapper, ...)``
* ``(mapper, axis={'index', 'columns'}, ...)``
We *highly* recommend using keyword arguments to clarify your
intent.
Rename columns using a mapping:
>>> df = pd.DataFrame({"A": [1, 2, 3], "B": [4, 5, 6]})
>>> df.rename(columns={"A": "a", "B": "c"})
a c
0 1 4
1 2 5
2 3 6
Rename index using a mapping:
>>> df.rename(index={0: "x", 1: "y", 2: "z"})
A B
x 1 4
y 2 5
z 3 6
Cast index labels to a different type:
>>> df.index
RangeIndex(start=0, stop=3, step=1)
>>> df.rename(index=str).index
Index(['0', '1', '2'], dtype='object')
>>> df.rename(columns={"A": "a", "B": "b", "C": "c"}, errors="raise")
Traceback (most recent call last):
KeyError: ['C'] not found in axis
Using axis-style parameters
>>> df.rename(str.lower, axis='columns')
a b
0 1 4
1 2 5
2 3 6
>>> df.rename({1: 2, 2: 4}, axis='index')
A B
0 1 4
2 2 5
4 3 6
"""
axes = validate_axis_style_args(self, args, kwargs, "mapper", "rename")
kwargs.update(axes)
# Pop these, since the values are in `kwargs` under different names
kwargs.pop("axis", None)
kwargs.pop("mapper", None)
return super().rename(**kwargs)
@Substitution(**_shared_doc_kwargs)
@Appender(NDFrame.fillna.__doc__)
def fillna(
self,
value=None,
method=None,
axis=None,
inplace=False,
limit=None,
downcast=None,
**kwargs
):
return super().fillna(
value=value,
method=method,
axis=axis,
inplace=inplace,
limit=limit,
downcast=downcast,
**kwargs
)
@Appender(_shared_docs["replace"] % _shared_doc_kwargs)
def replace(
self,
to_replace=None,
value=None,
inplace=False,
limit=None,
regex=False,
method="pad",
):
return super().replace(
to_replace=to_replace,
value=value,
inplace=inplace,
limit=limit,
regex=regex,
method=method,
)
@Appender(_shared_docs["shift"] % _shared_doc_kwargs)
def shift(self, periods=1, freq=None, axis=0, fill_value=None):
return super().shift(
periods=periods, freq=freq, axis=axis, fill_value=fill_value
)
def set_index(
self, keys, drop=True, append=False, inplace=False, verify_integrity=False
):
"""
Set the DataFrame index using existing columns.
Set the DataFrame index (row labels) using one or more existing
columns or arrays (of the correct length). The index can replace the
existing index or expand on it.
Parameters
----------
keys : label or array-like or list of labels/arrays
This parameter can be either a single column key, a single array of
the same length as the calling DataFrame, or a list containing an
arbitrary combination of column keys and arrays. Here, "array"
encompasses :class:`Series`, :class:`Index`, ``np.ndarray``, and
instances of :class:`~collections.abc.Iterator`.
drop : bool, default True
Delete columns to be used as the new index.
append : bool, default False
Whether to append columns to existing index.
inplace : bool, default False
Modify the DataFrame in place (do not create a new object).
verify_integrity : bool, default False
Check the new index for duplicates. Otherwise defer the check until
necessary. Setting to False will improve the performance of this
method.
Returns
-------
DataFrame
Changed row labels.
See Also
--------
DataFrame.reset_index : Opposite of set_index.
DataFrame.reindex : Change to new indices or expand indices.
DataFrame.reindex_like : Change to same indices as other DataFrame.
Examples
--------
>>> df = pd.DataFrame({'month': [1, 4, 7, 10],
... 'year': [2012, 2014, 2013, 2014],
... 'sale': [55, 40, 84, 31]})
>>> df
month year sale
0 1 2012 55
1 4 2014 40
2 7 2013 84
3 10 2014 31
Set the index to become the 'month' column:
>>> df.set_index('month')
year sale
month
1 2012 55
4 2014 40
7 2013 84
10 2014 31
Create a MultiIndex using columns 'year' and 'month':
>>> df.set_index(['year', 'month'])
sale
year month
2012 1 55
2014 4 40
2013 7 84
2014 10 31
Create a MultiIndex using an Index and a column:
>>> df.set_index([pd.Index([1, 2, 3, 4]), 'year'])
month sale
year
1 2012 1 55
2 2014 4 40
3 2013 7 84
4 2014 10 31
Create a MultiIndex using two Series:
>>> s = pd.Series([1, 2, 3, 4])
>>> df.set_index([s, s**2])
month year sale
1 1 1 2012 55
2 4 4 2014 40
3 9 7 2013 84
4 16 10 2014 31
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not isinstance(keys, list):
keys = [keys]
err_msg = (
'The parameter "keys" may be a column key, one-dimensional '
"array, or a list containing only valid column keys and "
"one-dimensional arrays."
)
missing = []
for col in keys:
if isinstance(
col, (ABCIndexClass, ABCSeries, np.ndarray, list, abc.Iterator)
):
# arrays are fine as long as they are one-dimensional
# iterators get converted to list below
if getattr(col, "ndim", 1) != 1:
raise ValueError(err_msg)
else:
# everything else gets tried as a key; see GH 24969
try:
found = col in self.columns
except TypeError:
raise TypeError(
err_msg + " Received column of " "type {}".format(type(col))
)
else:
if not found:
missing.append(col)
if missing:
raise KeyError("None of {} are in the columns".format(missing))
if inplace:
frame = self
else:
frame = self.copy()
arrays = []
names = []
if append:
names = [x for x in self.index.names]
if isinstance(self.index, ABCMultiIndex):
for i in range(self.index.nlevels):
arrays.append(self.index._get_level_values(i))
else:
arrays.append(self.index)
to_remove = []
for col in keys:
if isinstance(col, ABCMultiIndex):
for n in range(col.nlevels):
arrays.append(col._get_level_values(n))
names.extend(col.names)
elif isinstance(col, (ABCIndexClass, ABCSeries)):
# if Index then not MultiIndex (treated above)
arrays.append(col)
names.append(col.name)
elif isinstance(col, (list, np.ndarray)):
arrays.append(col)
names.append(None)
elif isinstance(col, abc.Iterator):
arrays.append(list(col))
names.append(None)
# from here, col can only be a column label
else:
arrays.append(frame[col]._values)
names.append(col)
if drop:
to_remove.append(col)
if len(arrays[-1]) != len(self):
# check newest element against length of calling frame, since
# ensure_index_from_sequences would not raise for append=False.
raise ValueError(
"Length mismatch: Expected {len_self} rows, "
"received array of length {len_col}".format(
len_self=len(self), len_col=len(arrays[-1])
)
)
index = ensure_index_from_sequences(arrays, names)
if verify_integrity and not index.is_unique:
duplicates = index[index.duplicated()].unique()
raise ValueError("Index has duplicate keys: {dup}".format(dup=duplicates))
# use set to handle duplicate column names gracefully in case of drop
for c in set(to_remove):
del frame[c]
# clear up memory usage
index._cleanup()
frame.index = index
if not inplace:
return frame
def reset_index(
self, level=None, drop=False, inplace=False, col_level=0, col_fill=""
):
"""
Reset the index, or a level of it.
Reset the index of the DataFrame, and use the default one instead.
If the DataFrame has a MultiIndex, this method can remove one or more
levels.
Parameters
----------
level : int, str, tuple, or list, default None
Only remove the given levels from the index. Removes all levels by
default.
drop : bool, default False
Do not try to insert index into dataframe columns. This resets
the index to the default integer index.
inplace : bool, default False
Modify the DataFrame in place (do not create a new object).
col_level : int or str, default 0
If the columns have multiple levels, determines which level the
labels are inserted into. By default it is inserted into the first
level.
col_fill : object, default ''
If the columns have multiple levels, determines how the other
levels are named. If None then the index name is repeated.
Returns
-------
DataFrame
DataFrame with the new index.
See Also
--------
DataFrame.set_index : Opposite of reset_index.
DataFrame.reindex : Change to new indices or expand indices.
DataFrame.reindex_like : Change to same indices as other DataFrame.
Examples
--------
>>> df = pd.DataFrame([('bird', 389.0),
... ('bird', 24.0),
... ('mammal', 80.5),
... ('mammal', np.nan)],
... index=['falcon', 'parrot', 'lion', 'monkey'],
... columns=('class', 'max_speed'))
>>> df
class max_speed
falcon bird 389.0
parrot bird 24.0
lion mammal 80.5
monkey mammal NaN
When we reset the index, the old index is added as a column, and a
new sequential index is used:
>>> df.reset_index()
index class max_speed
0 falcon bird 389.0
1 parrot bird 24.0
2 lion mammal 80.5
3 monkey mammal NaN
We can use the `drop` parameter to avoid the old index being added as
a column:
>>> df.reset_index(drop=True)
class max_speed
0 bird 389.0
1 bird 24.0
2 mammal 80.5
3 mammal NaN
You can also use `reset_index` with `MultiIndex`.
>>> index = pd.MultiIndex.from_tuples([('bird', 'falcon'),
... ('bird', 'parrot'),
... ('mammal', 'lion'),
... ('mammal', 'monkey')],
... names=['class', 'name'])
>>> columns = pd.MultiIndex.from_tuples([('speed', 'max'),
... ('species', 'type')])
>>> df = pd.DataFrame([(389.0, 'fly'),
... ( 24.0, 'fly'),
... ( 80.5, 'run'),
... (np.nan, 'jump')],
... index=index,
... columns=columns)
>>> df
speed species
max type
class name
bird falcon 389.0 fly
parrot 24.0 fly
mammal lion 80.5 run
monkey NaN jump
If the index has multiple levels, we can reset a subset of them:
>>> df.reset_index(level='class')
class speed species
max type
name
falcon bird 389.0 fly
parrot bird 24.0 fly
lion mammal 80.5 run
monkey mammal NaN jump
If we are not dropping the index, by default, it is placed in the top
level. We can place it in another level:
>>> df.reset_index(level='class', col_level=1)
speed species
class max type
name
falcon bird 389.0 fly
parrot bird 24.0 fly
lion mammal 80.5 run
monkey mammal NaN jump
When the index is inserted under another level, we can specify under
which one with the parameter `col_fill`:
>>> df.reset_index(level='class', col_level=1, col_fill='species')
species speed species
class max type
name
falcon bird 389.0 fly
parrot bird 24.0 fly
lion mammal 80.5 run
monkey mammal NaN jump
If we specify a nonexistent level for `col_fill`, it is created:
>>> df.reset_index(level='class', col_level=1, col_fill='genus')
genus speed species
class max type
name
falcon bird 389.0 fly
parrot bird 24.0 fly
lion mammal 80.5 run
monkey mammal NaN jump
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if inplace:
new_obj = self
else:
new_obj = self.copy()
def _maybe_casted_values(index, labels=None):
values = index._values
if not isinstance(index, (PeriodIndex, DatetimeIndex)):
if values.dtype == np.object_:
values = lib.maybe_convert_objects(values)
# if we have the labels, extract the values with a mask
if labels is not None:
mask = labels == -1
# we can have situations where the whole mask is -1,
# meaning there is nothing found in labels, so make all nan's
if mask.all():
values = np.empty(len(mask))
values.fill(np.nan)
else:
values = values.take(labels)
# TODO(https://github.com/pandas-dev/pandas/issues/24206)
# Push this into maybe_upcast_putmask?
# We can't pass EAs there right now. Looks a bit
# complicated.
# So we unbox the ndarray_values, op, re-box.
values_type = type(values)
values_dtype = values.dtype
if issubclass(values_type, DatetimeLikeArray):
values = values._data
if mask.any():
values, changed = maybe_upcast_putmask(values, mask, np.nan)
if issubclass(values_type, DatetimeLikeArray):
values = values_type(values, dtype=values_dtype)
return values
new_index = ibase.default_index(len(new_obj))
if level is not None:
if not isinstance(level, (tuple, list)):
level = [level]
level = [self.index._get_level_number(lev) for lev in level]
if len(level) < self.index.nlevels:
new_index = self.index.droplevel(level)
if not drop:
if isinstance(self.index, MultiIndex):
names = [
n if n is not None else ("level_%d" % i)
for (i, n) in enumerate(self.index.names)
]
to_insert = zip(self.index.levels, self.index.codes)
else:
default = "index" if "index" not in self else "level_0"
names = [default] if self.index.name is None else [self.index.name]
to_insert = ((self.index, None),)
multi_col = isinstance(self.columns, MultiIndex)
for i, (lev, lab) in reversed(list(enumerate(to_insert))):
if not (level is None or i in level):
continue
name = names[i]
if multi_col:
col_name = list(name) if isinstance(name, tuple) else [name]
if col_fill is None:
if len(col_name) not in (1, self.columns.nlevels):
raise ValueError(
"col_fill=None is incompatible "
"with incomplete column name "
"{}".format(name)
)
col_fill = col_name[0]
lev_num = self.columns._get_level_number(col_level)
name_lst = [col_fill] * lev_num + col_name
missing = self.columns.nlevels - len(name_lst)
name_lst += [col_fill] * missing
name = tuple(name_lst)
# to ndarray and maybe infer different dtype
level_values = _maybe_casted_values(lev, lab)
new_obj.insert(0, name, level_values)
new_obj.index = new_index
if not inplace:
return new_obj
# ----------------------------------------------------------------------
# Reindex-based selection methods
@Appender(_shared_docs["isna"] % _shared_doc_kwargs)
def isna(self):
return super().isna()
@Appender(_shared_docs["isna"] % _shared_doc_kwargs)
def isnull(self):
return super().isnull()
@Appender(_shared_docs["notna"] % _shared_doc_kwargs)
def notna(self):
return super().notna()
@Appender(_shared_docs["notna"] % _shared_doc_kwargs)
def notnull(self):
return super().notnull()
def dropna(self, axis=0, how="any", thresh=None, subset=None, inplace=False):
"""
Remove missing values.
See the :ref:`User Guide <missing_data>` for more on which values are
considered missing, and how to work with missing data.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
Determine if rows or columns which contain missing values are
removed.
* 0, or 'index' : Drop rows which contain missing values.
* 1, or 'columns' : Drop columns which contain missing value.
.. deprecated:: 0.23.0
Pass tuple or list to drop on multiple axes.
Only a single axis is allowed.
how : {'any', 'all'}, default 'any'
Determine if row or column is removed from DataFrame, when we have
at least one NA or all NA.
* 'any' : If any NA values are present, drop that row or column.
* 'all' : If all values are NA, drop that row or column.
thresh : int, optional
Require that many non-NA values.
subset : array-like, optional
Labels along other axis to consider, e.g. if you are dropping rows
these would be a list of columns to include.
inplace : bool, default False
If True, do operation inplace and return None.
Returns
-------
DataFrame
DataFrame with NA entries dropped from it.
See Also
--------
DataFrame.isna: Indicate missing values.
DataFrame.notna : Indicate existing (non-missing) values.
DataFrame.fillna : Replace missing values.
Series.dropna : Drop missing values.
Index.dropna : Drop missing indices.
Examples
--------
>>> df = pd.DataFrame({"name": ['Alfred', 'Batman', 'Catwoman'],
... "toy": [np.nan, 'Batmobile', 'Bullwhip'],
... "born": [pd.NaT, pd.Timestamp("1940-04-25"),
... pd.NaT]})
>>> df
name toy born
0 Alfred NaN NaT
1 Batman Batmobile 1940-04-25
2 Catwoman Bullwhip NaT
Drop the rows where at least one element is missing.
>>> df.dropna()
name toy born
1 Batman Batmobile 1940-04-25
Drop the columns where at least one element is missing.
>>> df.dropna(axis='columns')
name
0 Alfred
1 Batman
2 Catwoman
Drop the rows where all elements are missing.
>>> df.dropna(how='all')
name toy born
0 Alfred NaN NaT
1 Batman Batmobile 1940-04-25
2 Catwoman Bullwhip NaT
Keep only the rows with at least 2 non-NA values.
>>> df.dropna(thresh=2)
name toy born
1 Batman Batmobile 1940-04-25
2 Catwoman Bullwhip NaT
Define in which columns to look for missing values.
>>> df.dropna(subset=['name', 'born'])
name toy born
1 Batman Batmobile 1940-04-25
Keep the DataFrame with valid entries in the same variable.
>>> df.dropna(inplace=True)
>>> df
name toy born
1 Batman Batmobile 1940-04-25
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if isinstance(axis, (tuple, list)):
# GH20987
msg = (
"supplying multiple axes to axis is deprecated and "
"will be removed in a future version."
)
warnings.warn(msg, FutureWarning, stacklevel=2)
result = self
for ax in axis:
result = result.dropna(how=how, thresh=thresh, subset=subset, axis=ax)
else:
axis = self._get_axis_number(axis)
agg_axis = 1 - axis
agg_obj = self
if subset is not None:
ax = self._get_axis(agg_axis)
indices = ax.get_indexer_for(subset)
check = indices == -1
if check.any():
raise KeyError(list(np.compress(check, subset)))
agg_obj = self.take(indices, axis=agg_axis)
count = agg_obj.count(axis=agg_axis)
if thresh is not None:
mask = count >= thresh
elif how == "any":
mask = count == len(agg_obj._get_axis(agg_axis))
elif how == "all":
mask = count > 0
else:
if how is not None:
raise ValueError("invalid how option: {h}".format(h=how))
else:
raise TypeError("must specify how or thresh")
result = self.loc(axis=axis)[mask]
if inplace:
self._update_inplace(result)
else:
return result
def drop_duplicates(self, subset=None, keep="first", inplace=False):
"""
Return DataFrame with duplicate rows removed, optionally only
considering certain columns. Indexes, including time indexes
are ignored.
Parameters
----------
subset : column label or sequence of labels, optional
Only consider certain columns for identifying duplicates, by
default use all of the columns
keep : {'first', 'last', False}, default 'first'
- ``first`` : Drop duplicates except for the first occurrence.
- ``last`` : Drop duplicates except for the last occurrence.
- False : Drop all duplicates.
inplace : boolean, default False
Whether to drop duplicates in place or to return a copy
Returns
-------
DataFrame
"""
if self.empty:
return self.copy()
inplace = validate_bool_kwarg(inplace, "inplace")
duplicated = self.duplicated(subset, keep=keep)
if inplace:
inds, = (-duplicated)._ndarray_values.nonzero()
new_data = self._data.take(inds)
self._update_inplace(new_data)
else:
return self[-duplicated]
def duplicated(self, subset=None, keep="first"):
"""
Return boolean Series denoting duplicate rows, optionally only
considering certain columns.
Parameters
----------
subset : column label or sequence of labels, optional
Only consider certain columns for identifying duplicates, by
default use all of the columns
keep : {'first', 'last', False}, default 'first'
- ``first`` : Mark duplicates as ``True`` except for the
first occurrence.
- ``last`` : Mark duplicates as ``True`` except for the
last occurrence.
- False : Mark all duplicates as ``True``.
Returns
-------
Series
"""
from pandas.core.sorting import get_group_index
from pandas._libs.hashtable import duplicated_int64, _SIZE_HINT_LIMIT
if self.empty:
return Series(dtype=bool)
def f(vals):
labels, shape = algorithms.factorize(
vals, size_hint=min(len(self), _SIZE_HINT_LIMIT)
)
return labels.astype("i8", copy=False), len(shape)
if subset is None:
subset = self.columns
elif (
not np.iterable(subset)
or isinstance(subset, str)
or isinstance(subset, tuple)
and subset in self.columns
):
subset = (subset,)
# Verify all columns in subset exist in the queried dataframe
# Otherwise, raise a KeyError, same as if you try to __getitem__ with a
# key that doesn't exist.
diff = Index(subset).difference(self.columns)
if not diff.empty:
raise KeyError(diff)
vals = (col.values for name, col in self.items() if name in subset)
labels, shape = map(list, zip(*map(f, vals)))
ids = get_group_index(labels, shape, sort=False, xnull=False)
return Series(duplicated_int64(ids, keep), index=self.index)
# ----------------------------------------------------------------------
# Sorting
@Substitution(**_shared_doc_kwargs)
@Appender(NDFrame.sort_values.__doc__)
def sort_values(
self,
by,
axis=0,
ascending=True,
inplace=False,
kind="quicksort",
na_position="last",
):
inplace = validate_bool_kwarg(inplace, "inplace")
axis = self._get_axis_number(axis)
if not isinstance(by, list):
by = [by]
if is_sequence(ascending) and len(by) != len(ascending):
raise ValueError(
"Length of ascending (%d) != length of by (%d)"
% (len(ascending), len(by))
)
if len(by) > 1:
from pandas.core.sorting import lexsort_indexer
keys = [self._get_label_or_level_values(x, axis=axis) for x in by]
indexer = lexsort_indexer(keys, orders=ascending, na_position=na_position)
indexer = ensure_platform_int(indexer)
else:
from pandas.core.sorting import nargsort
by = by[0]
k = self._get_label_or_level_values(by, axis=axis)
if isinstance(ascending, (tuple, list)):
ascending = ascending[0]
indexer = nargsort(
k, kind=kind, ascending=ascending, na_position=na_position
)
new_data = self._data.take(
indexer, axis=self._get_block_manager_axis(axis), verify=False
)
if inplace:
return self._update_inplace(new_data)
else:
return self._constructor(new_data).__finalize__(self)
@Substitution(**_shared_doc_kwargs)
@Appender(NDFrame.sort_index.__doc__)
def sort_index(
self,
axis=0,
level=None,
ascending=True,
inplace=False,
kind="quicksort",
na_position="last",
sort_remaining=True,
by=None,
):
# TODO: this can be combined with Series.sort_index impl as
# almost identical
inplace = validate_bool_kwarg(inplace, "inplace")
# 10726
if by is not None:
warnings.warn(
"by argument to sort_index is deprecated, "
"please use .sort_values(by=...)",
FutureWarning,
stacklevel=2,
)
if level is not None:
raise ValueError("unable to simultaneously sort by and level")
return self.sort_values(by, axis=axis, ascending=ascending, inplace=inplace)
axis = self._get_axis_number(axis)
labels = self._get_axis(axis)
# make sure that the axis is lexsorted to start
# if not we need to reconstruct to get the correct indexer
labels = labels._sort_levels_monotonic()
if level is not None:
new_axis, indexer = labels.sortlevel(
level, ascending=ascending, sort_remaining=sort_remaining
)
elif isinstance(labels, MultiIndex):
from pandas.core.sorting import lexsort_indexer
indexer = lexsort_indexer(
labels._get_codes_for_sorting(),
orders=ascending,
na_position=na_position,
)
else:
from pandas.core.sorting import nargsort
# Check monotonic-ness before sort an index
# GH11080
if (ascending and labels.is_monotonic_increasing) or (
not ascending and labels.is_monotonic_decreasing
):
if inplace:
return
else:
return self.copy()
indexer = nargsort(
labels, kind=kind, ascending=ascending, na_position=na_position
)
baxis = self._get_block_manager_axis(axis)
new_data = self._data.take(indexer, axis=baxis, verify=False)
# reconstruct axis if needed
new_data.axes[baxis] = new_data.axes[baxis]._sort_levels_monotonic()
if inplace:
return self._update_inplace(new_data)
else:
return self._constructor(new_data).__finalize__(self)
def nlargest(self, n, columns, keep="first"):
"""
Return the first `n` rows ordered by `columns` in descending order.
Return the first `n` rows with the largest values in `columns`, in
descending order. The columns that are not specified are returned as
well, but not used for ordering.
This method is equivalent to
``df.sort_values(columns, ascending=False).head(n)``, but more
performant.
Parameters
----------
n : int
Number of rows to return.
columns : label or list of labels
Column label(s) to order by.
keep : {'first', 'last', 'all'}, default 'first'
Where there are duplicate values:
- `first` : prioritize the first occurrence(s)
- `last` : prioritize the last occurrence(s)
- ``all`` : do not drop any duplicates, even it means
selecting more than `n` items.
.. versionadded:: 0.24.0
Returns
-------
DataFrame
The first `n` rows ordered by the given columns in descending
order.
See Also
--------
DataFrame.nsmallest : Return the first `n` rows ordered by `columns` in
ascending order.
DataFrame.sort_values : Sort DataFrame by the values.
DataFrame.head : Return the first `n` rows without re-ordering.
Notes
-----
This function cannot be used with all column types. For example, when
specifying columns with `object` or `category` dtypes, ``TypeError`` is
raised.
Examples
--------
>>> df = pd.DataFrame({'population': [59000000, 65000000, 434000,
... 434000, 434000, 337000, 11300,
... 11300, 11300],
... 'GDP': [1937894, 2583560 , 12011, 4520, 12128,
... 17036, 182, 38, 311],
... 'alpha-2': ["IT", "FR", "MT", "MV", "BN",
... "IS", "NR", "TV", "AI"]},
... index=["Italy", "France", "Malta",
... "Maldives", "Brunei", "Iceland",
... "Nauru", "Tuvalu", "Anguilla"])
>>> df
population GDP alpha-2
Italy 59000000 1937894 IT
France 65000000 2583560 FR
Malta 434000 12011 MT
Maldives 434000 4520 MV
Brunei 434000 12128 BN
Iceland 337000 17036 IS
Nauru 11300 182 NR
Tuvalu 11300 38 TV
Anguilla 11300 311 AI
In the following example, we will use ``nlargest`` to select the three
rows having the largest values in column "population".
>>> df.nlargest(3, 'population')
population GDP alpha-2
France 65000000 2583560 FR
Italy 59000000 1937894 IT
Malta 434000 12011 MT
When using ``keep='last'``, ties are resolved in reverse order:
>>> df.nlargest(3, 'population', keep='last')
population GDP alpha-2
France 65000000 2583560 FR
Italy 59000000 1937894 IT
Brunei 434000 12128 BN
When using ``keep='all'``, all duplicate items are maintained:
>>> df.nlargest(3, 'population', keep='all')
population GDP alpha-2
France 65000000 2583560 FR
Italy 59000000 1937894 IT
Malta 434000 12011 MT
Maldives 434000 4520 MV
Brunei 434000 12128 BN
To order by the largest values in column "population" and then "GDP",
we can specify multiple columns like in the next example.
>>> df.nlargest(3, ['population', 'GDP'])
population GDP alpha-2
France 65000000 2583560 FR
Italy 59000000 1937894 IT
Brunei 434000 12128 BN
"""
return algorithms.SelectNFrame(self, n=n, keep=keep, columns=columns).nlargest()
def nsmallest(self, n, columns, keep="first"):
"""
Return the first `n` rows ordered by `columns` in ascending order.
Return the first `n` rows with the smallest values in `columns`, in
ascending order. The columns that are not specified are returned as
well, but not used for ordering.
This method is equivalent to
``df.sort_values(columns, ascending=True).head(n)``, but more
performant.
Parameters
----------
n : int
Number of items to retrieve.
columns : list or str
Column name or names to order by.
keep : {'first', 'last', 'all'}, default 'first'
Where there are duplicate values:
- ``first`` : take the first occurrence.
- ``last`` : take the last occurrence.
- ``all`` : do not drop any duplicates, even it means
selecting more than `n` items.
.. versionadded:: 0.24.0
Returns
-------
DataFrame
See Also
--------
DataFrame.nlargest : Return the first `n` rows ordered by `columns` in
descending order.
DataFrame.sort_values : Sort DataFrame by the values.
DataFrame.head : Return the first `n` rows without re-ordering.
Examples
--------
>>> df = pd.DataFrame({'population': [59000000, 65000000, 434000,
... 434000, 434000, 337000, 11300,
... 11300, 11300],
... 'GDP': [1937894, 2583560 , 12011, 4520, 12128,
... 17036, 182, 38, 311],
... 'alpha-2': ["IT", "FR", "MT", "MV", "BN",
... "IS", "NR", "TV", "AI"]},
... index=["Italy", "France", "Malta",
... "Maldives", "Brunei", "Iceland",
... "Nauru", "Tuvalu", "Anguilla"])
>>> df
population GDP alpha-2
Italy 59000000 1937894 IT
France 65000000 2583560 FR
Malta 434000 12011 MT
Maldives 434000 4520 MV
Brunei 434000 12128 BN
Iceland 337000 17036 IS
Nauru 11300 182 NR
Tuvalu 11300 38 TV
Anguilla 11300 311 AI
In the following example, we will use ``nsmallest`` to select the
three rows having the smallest values in column "a".
>>> df.nsmallest(3, 'population')
population GDP alpha-2
Nauru 11300 182 NR
Tuvalu 11300 38 TV
Anguilla 11300 311 AI
When using ``keep='last'``, ties are resolved in reverse order:
>>> df.nsmallest(3, 'population', keep='last')
population GDP alpha-2
Anguilla 11300 311 AI
Tuvalu 11300 38 TV
Nauru 11300 182 NR
When using ``keep='all'``, all duplicate items are maintained:
>>> df.nsmallest(3, 'population', keep='all')
population GDP alpha-2
Nauru 11300 182 NR
Tuvalu 11300 38 TV
Anguilla 11300 311 AI
To order by the largest values in column "a" and then "c", we can
specify multiple columns like in the next example.
>>> df.nsmallest(3, ['population', 'GDP'])
population GDP alpha-2
Tuvalu 11300 38 TV
Nauru 11300 182 NR
Anguilla 11300 311 AI
"""
return algorithms.SelectNFrame(
self, n=n, keep=keep, columns=columns
).nsmallest()
def swaplevel(self, i=-2, j=-1, axis=0):
"""
Swap levels i and j in a MultiIndex on a particular axis.
Parameters
----------
i, j : int, string (can be mixed)
Level of index to be swapped. Can pass level name as string.
Returns
-------
DataFrame
"""
result = self.copy()
axis = self._get_axis_number(axis)
if axis == 0:
result.index = result.index.swaplevel(i, j)
else:
result.columns = result.columns.swaplevel(i, j)
return result
def reorder_levels(self, order, axis=0):
"""
Rearrange index levels using input order. May not drop or
duplicate levels.
Parameters
----------
order : list of int or list of str
List representing new level order. Reference level by number
(position) or by key (label).
axis : int
Where to reorder levels.
Returns
-------
type of caller (new object)
"""
axis = self._get_axis_number(axis)
if not isinstance(self._get_axis(axis), MultiIndex): # pragma: no cover
raise TypeError("Can only reorder levels on a hierarchical axis.")
result = self.copy()
if axis == 0:
result.index = result.index.reorder_levels(order)
else:
result.columns = result.columns.reorder_levels(order)
return result
# ----------------------------------------------------------------------
# Arithmetic / combination related
def _combine_frame(self, other, func, fill_value=None, level=None):
this, other = self.align(other, join="outer", level=level, copy=False)
new_index, new_columns = this.index, this.columns
def _arith_op(left, right):
# for the mixed_type case where we iterate over columns,
# _arith_op(left, right) is equivalent to
# left._binop(right, func, fill_value=fill_value)
left, right = ops.fill_binop(left, right, fill_value)
return func(left, right)
if ops.should_series_dispatch(this, other, func):
# iterate over columns
return ops.dispatch_to_series(this, other, _arith_op)
else:
result = _arith_op(this.values, other.values)
return self._constructor(
result, index=new_index, columns=new_columns, copy=False
)
def _combine_match_index(self, other, func, level=None):
left, right = self.align(other, join="outer", axis=0, level=level, copy=False)
assert left.index.equals(right.index)
if left._is_mixed_type or right._is_mixed_type:
# operate column-wise; avoid costly object-casting in `.values`
return ops.dispatch_to_series(left, right, func)
else:
# fastpath --> operate directly on values
with np.errstate(all="ignore"):
new_data = func(left.values.T, right.values).T
return self._constructor(
new_data, index=left.index, columns=self.columns, copy=False
)
def _combine_match_columns(self, other, func, level=None):
assert isinstance(other, Series)
left, right = self.align(other, join="outer", axis=1, level=level, copy=False)
assert left.columns.equals(right.index)
return ops.dispatch_to_series(left, right, func, axis="columns")
def _combine_const(self, other, func):
assert lib.is_scalar(other) or np.ndim(other) == 0
return ops.dispatch_to_series(self, other, func)
def combine(self, other, func, fill_value=None, overwrite=True):
"""
Perform column-wise combine with another DataFrame.
Combines a DataFrame with `other` DataFrame using `func`
to element-wise combine columns. The row and column indexes of the
resulting DataFrame will be the union of the two.
Parameters
----------
other : DataFrame
The DataFrame to merge column-wise.
func : function
Function that takes two series as inputs and return a Series or a
scalar. Used to merge the two dataframes column by columns.
fill_value : scalar value, default None
The value to fill NaNs with prior to passing any column to the
merge func.
overwrite : bool, default True
If True, columns in `self` that do not exist in `other` will be
overwritten with NaNs.
Returns
-------
DataFrame
Combination of the provided DataFrames.
See Also
--------
DataFrame.combine_first : Combine two DataFrame objects and default to
non-null values in frame calling the method.
Examples
--------
Combine using a simple function that chooses the smaller column.
>>> df1 = pd.DataFrame({'A': [0, 0], 'B': [4, 4]})
>>> df2 = pd.DataFrame({'A': [1, 1], 'B': [3, 3]})
>>> take_smaller = lambda s1, s2: s1 if s1.sum() < s2.sum() else s2
>>> df1.combine(df2, take_smaller)
A B
0 0 3
1 0 3
Example using a true element-wise combine function.
>>> df1 = pd.DataFrame({'A': [5, 0], 'B': [2, 4]})
>>> df2 = pd.DataFrame({'A': [1, 1], 'B': [3, 3]})
>>> df1.combine(df2, np.minimum)
A B
0 1 2
1 0 3
Using `fill_value` fills Nones prior to passing the column to the
merge function.
>>> df1 = pd.DataFrame({'A': [0, 0], 'B': [None, 4]})
>>> df2 = pd.DataFrame({'A': [1, 1], 'B': [3, 3]})
>>> df1.combine(df2, take_smaller, fill_value=-5)
A B
0 0 -5.0
1 0 4.0
However, if the same element in both dataframes is None, that None
is preserved
>>> df1 = pd.DataFrame({'A': [0, 0], 'B': [None, 4]})
>>> df2 = pd.DataFrame({'A': [1, 1], 'B': [None, 3]})
>>> df1.combine(df2, take_smaller, fill_value=-5)
A B
0 0 -5.0
1 0 3.0
Example that demonstrates the use of `overwrite` and behavior when
the axis differ between the dataframes.
>>> df1 = pd.DataFrame({'A': [0, 0], 'B': [4, 4]})
>>> df2 = pd.DataFrame({'B': [3, 3], 'C': [-10, 1], }, index=[1, 2])
>>> df1.combine(df2, take_smaller)
A B C
0 NaN NaN NaN
1 NaN 3.0 -10.0
2 NaN 3.0 1.0
>>> df1.combine(df2, take_smaller, overwrite=False)
A B C
0 0.0 NaN NaN
1 0.0 3.0 -10.0
2 NaN 3.0 1.0
Demonstrating the preference of the passed in dataframe.
>>> df2 = pd.DataFrame({'B': [3, 3], 'C': [1, 1], }, index=[1, 2])
>>> df2.combine(df1, take_smaller)
A B C
0 0.0 NaN NaN
1 0.0 3.0 NaN
2 NaN 3.0 NaN
>>> df2.combine(df1, take_smaller, overwrite=False)
A B C
0 0.0 NaN NaN
1 0.0 3.0 1.0
2 NaN 3.0 1.0
"""
other_idxlen = len(other.index) # save for compare
this, other = self.align(other, copy=False)
new_index = this.index
if other.empty and len(new_index) == len(self.index):
return self.copy()
if self.empty and len(other) == other_idxlen:
return other.copy()
# sorts if possible
new_columns = this.columns.union(other.columns)
do_fill = fill_value is not None
result = {}
for col in new_columns:
series = this[col]
otherSeries = other[col]
this_dtype = series.dtype
other_dtype = otherSeries.dtype
this_mask = isna(series)
other_mask = isna(otherSeries)
# don't overwrite columns unnecessarily
# DO propagate if this column is not in the intersection
if not overwrite and other_mask.all():
result[col] = this[col].copy()
continue
if do_fill:
series = series.copy()
otherSeries = otherSeries.copy()
series[this_mask] = fill_value
otherSeries[other_mask] = fill_value
if col not in self.columns:
# If self DataFrame does not have col in other DataFrame,
# try to promote series, which is all NaN, as other_dtype.
new_dtype = other_dtype
try:
series = series.astype(new_dtype, copy=False)
except ValueError:
# e.g. new_dtype is integer types
pass
else:
# if we have different dtypes, possibly promote
new_dtype = find_common_type([this_dtype, other_dtype])
if not is_dtype_equal(this_dtype, new_dtype):
series = series.astype(new_dtype)
if not is_dtype_equal(other_dtype, new_dtype):
otherSeries = otherSeries.astype(new_dtype)
arr = func(series, otherSeries)
arr = maybe_downcast_to_dtype(arr, this_dtype)
result[col] = arr
# convert_objects just in case
return self._constructor(result, index=new_index, columns=new_columns)
def combine_first(self, other):
"""
Update null elements with value in the same location in `other`.
Combine two DataFrame objects by filling null values in one DataFrame
with non-null values from other DataFrame. The row and column indexes
of the resulting DataFrame will be the union of the two.
Parameters
----------
other : DataFrame
Provided DataFrame to use to fill null values.
Returns
-------
DataFrame
See Also
--------
DataFrame.combine : Perform series-wise operation on two DataFrames
using a given function.
Examples
--------
>>> df1 = pd.DataFrame({'A': [None, 0], 'B': [None, 4]})
>>> df2 = pd.DataFrame({'A': [1, 1], 'B': [3, 3]})
>>> df1.combine_first(df2)
A B
0 1.0 3.0
1 0.0 4.0
Null values still persist if the location of that null value
does not exist in `other`
>>> df1 = pd.DataFrame({'A': [None, 0], 'B': [4, None]})
>>> df2 = pd.DataFrame({'B': [3, 3], 'C': [1, 1]}, index=[1, 2])
>>> df1.combine_first(df2)
A B C
0 NaN 4.0 NaN
1 0.0 3.0 1.0
2 NaN 3.0 1.0
"""
import pandas.core.computation.expressions as expressions
def extract_values(arr):
# Does two things:
# 1. maybe gets the values from the Series / Index
# 2. convert datelike to i8
if isinstance(arr, (ABCIndexClass, ABCSeries)):
arr = arr._values
if needs_i8_conversion(arr):
if is_extension_array_dtype(arr.dtype):
arr = arr.asi8
else:
arr = arr.view("i8")
return arr
def combiner(x, y):
mask = isna(x)
if isinstance(mask, (ABCIndexClass, ABCSeries)):
mask = mask._values
x_values = extract_values(x)
y_values = extract_values(y)
# If the column y in other DataFrame is not in first DataFrame,
# just return y_values.
if y.name not in self.columns:
return y_values
return expressions.where(mask, y_values, x_values)
return self.combine(other, combiner, overwrite=False)
@deprecate_kwarg(
old_arg_name="raise_conflict",
new_arg_name="errors",
mapping={False: "ignore", True: "raise"},
)
def update(
self, other, join="left", overwrite=True, filter_func=None, errors="ignore"
):
"""
Modify in place using non-NA values from another DataFrame.
Aligns on indices. There is no return value.
Parameters
----------
other : DataFrame, or object coercible into a DataFrame
Should have at least one matching index/column label
with the original DataFrame. If a Series is passed,
its name attribute must be set, and that will be
used as the column name to align with the original DataFrame.
join : {'left'}, default 'left'
Only left join is implemented, keeping the index and columns of the
original object.
overwrite : bool, default True
How to handle non-NA values for overlapping keys:
* True: overwrite original DataFrame's values
with values from `other`.
* False: only update values that are NA in
the original DataFrame.
filter_func : callable(1d-array) -> bool 1d-array, optional
Can choose to replace values other than NA. Return True for values
that should be updated.
errors : {'raise', 'ignore'}, default 'ignore'
If 'raise', will raise a ValueError if the DataFrame and `other`
both contain non-NA data in the same place.
.. versionchanged :: 0.24.0
Changed from `raise_conflict=False|True`
to `errors='ignore'|'raise'`.
Returns
-------
None : method directly changes calling object
Raises
------
ValueError
* When `errors='raise'` and there's overlapping non-NA data.
* When `errors` is not either `'ignore'` or `'raise'`
NotImplementedError
* If `join != 'left'`
See Also
--------
dict.update : Similar method for dictionaries.
DataFrame.merge : For column(s)-on-columns(s) operations.
Examples
--------
>>> df = pd.DataFrame({'A': [1, 2, 3],
... 'B': [400, 500, 600]})
>>> new_df = pd.DataFrame({'B': [4, 5, 6],
... 'C': [7, 8, 9]})
>>> df.update(new_df)
>>> df
A B
0 1 4
1 2 5
2 3 6
The DataFrame's length does not increase as a result of the update,
only values at matching index/column labels are updated.
>>> df = pd.DataFrame({'A': ['a', 'b', 'c'],
... 'B': ['x', 'y', 'z']})
>>> new_df = pd.DataFrame({'B': ['d', 'e', 'f', 'g', 'h', 'i']})
>>> df.update(new_df)
>>> df
A B
0 a d
1 b e
2 c f
For Series, it's name attribute must be set.
>>> df = pd.DataFrame({'A': ['a', 'b', 'c'],
... 'B': ['x', 'y', 'z']})
>>> new_column = pd.Series(['d', 'e'], name='B', index=[0, 2])
>>> df.update(new_column)
>>> df
A B
0 a d
1 b y
2 c e
>>> df = pd.DataFrame({'A': ['a', 'b', 'c'],
... 'B': ['x', 'y', 'z']})
>>> new_df = pd.DataFrame({'B': ['d', 'e']}, index=[1, 2])
>>> df.update(new_df)
>>> df
A B
0 a x
1 b d
2 c e
If `other` contains NaNs the corresponding values are not updated
in the original dataframe.
>>> df = pd.DataFrame({'A': [1, 2, 3],
... 'B': [400, 500, 600]})
>>> new_df = pd.DataFrame({'B': [4, np.nan, 6]})
>>> df.update(new_df)
>>> df
A B
0 1 4.0
1 2 500.0
2 3 6.0
"""
import pandas.core.computation.expressions as expressions
# TODO: Support other joins
if join != "left": # pragma: no cover
raise NotImplementedError("Only left join is supported")
if errors not in ["ignore", "raise"]:
raise ValueError(
"The parameter errors must be either " "'ignore' or 'raise'"
)
if not isinstance(other, DataFrame):
other = DataFrame(other)
other = other.reindex_like(self)
for col in self.columns:
this = self[col]._values
that = other[col]._values
if filter_func is not None:
with np.errstate(all="ignore"):
mask = ~filter_func(this) | isna(that)
else:
if errors == "raise":
mask_this = notna(that)
mask_that = notna(this)
if any(mask_this & mask_that):
raise ValueError("Data overlaps.")
if overwrite:
mask = isna(that)
else:
mask = notna(this)
# don't overwrite columns unnecessarily
if mask.all():
continue
self[col] = expressions.where(mask, this, that)
# ----------------------------------------------------------------------
# Data reshaping
_shared_docs[
"pivot"
] = """
Return reshaped DataFrame organized by given index / column values.
Reshape data (produce a "pivot" table) based on column values. Uses
unique values from specified `index` / `columns` to form axes of the
resulting DataFrame. This function does not support data
aggregation, multiple values will result in a MultiIndex in the
columns. See the :ref:`User Guide <reshaping>` for more on reshaping.
Parameters
----------%s
index : string or object, optional
Column to use to make new frame's index. If None, uses
existing index.
columns : string or object
Column to use to make new frame's columns.
values : string, object or a list of the previous, optional
Column(s) to use for populating new frame's values. If not
specified, all remaining columns will be used and the result will
have hierarchically indexed columns.
.. versionchanged :: 0.23.0
Also accept list of column names.
Returns
-------
DataFrame
Returns reshaped DataFrame.
Raises
------
ValueError:
When there are any `index`, `columns` combinations with multiple
values. `DataFrame.pivot_table` when you need to aggregate.
See Also
--------
DataFrame.pivot_table : Generalization of pivot that can handle
duplicate values for one index/column pair.
DataFrame.unstack : Pivot based on the index values instead of a
column.
Notes
-----
For finer-tuned control, see hierarchical indexing documentation along
with the related stack/unstack methods.
Examples
--------
>>> df = pd.DataFrame({'foo': ['one', 'one', 'one', 'two', 'two',
... 'two'],
... 'bar': ['A', 'B', 'C', 'A', 'B', 'C'],
... 'baz': [1, 2, 3, 4, 5, 6],
... 'zoo': ['x', 'y', 'z', 'q', 'w', 't']})
>>> df
foo bar baz zoo
0 one A 1 x
1 one B 2 y
2 one C 3 z
3 two A 4 q
4 two B 5 w
5 two C 6 t
>>> df.pivot(index='foo', columns='bar', values='baz')
bar A B C
foo
one 1 2 3
two 4 5 6
>>> df.pivot(index='foo', columns='bar')['baz']
bar A B C
foo
one 1 2 3
two 4 5 6
>>> df.pivot(index='foo', columns='bar', values=['baz', 'zoo'])
baz zoo
bar A B C A B C
foo
one 1 2 3 x y z
two 4 5 6 q w t
A ValueError is raised if there are any duplicates.
>>> df = pd.DataFrame({"foo": ['one', 'one', 'two', 'two'],
... "bar": ['A', 'A', 'B', 'C'],
... "baz": [1, 2, 3, 4]})
>>> df
foo bar baz
0 one A 1
1 one A 2
2 two B 3
3 two C 4
Notice that the first two rows are the same for our `index`
and `columns` arguments.
>>> df.pivot(index='foo', columns='bar', values='baz')
Traceback (most recent call last):
...
ValueError: Index contains duplicate entries, cannot reshape
"""
@Substitution("")
@Appender(_shared_docs["pivot"])
def pivot(self, index=None, columns=None, values=None):
from pandas.core.reshape.pivot import pivot
return pivot(self, index=index, columns=columns, values=values)
_shared_docs[
"pivot_table"
] = """
Create a spreadsheet-style pivot table as a DataFrame. The levels in
the pivot table will be stored in MultiIndex objects (hierarchical
indexes) on the index and columns of the result DataFrame.
Parameters
----------%s
values : column to aggregate, optional
index : column, Grouper, array, or list of the previous
If an array is passed, it must be the same length as the data. The
list can contain any of the other types (except list).
Keys to group by on the pivot table index. If an array is passed,
it is being used as the same manner as column values.
columns : column, Grouper, array, or list of the previous
If an array is passed, it must be the same length as the data. The
list can contain any of the other types (except list).
Keys to group by on the pivot table column. If an array is passed,
it is being used as the same manner as column values.
aggfunc : function, list of functions, dict, default numpy.mean
If list of functions passed, the resulting pivot table will have
hierarchical columns whose top level are the function names
(inferred from the function objects themselves)
If dict is passed, the key is column to aggregate and value
is function or list of functions
fill_value : scalar, default None
Value to replace missing values with
margins : boolean, default False
Add all row / columns (e.g. for subtotal / grand totals)
dropna : boolean, default True
Do not include columns whose entries are all NaN
margins_name : string, default 'All'
Name of the row / column that will contain the totals
when margins is True.
observed : boolean, default False
This only applies if any of the groupers are Categoricals.
If True: only show observed values for categorical groupers.
If False: show all values for categorical groupers.
.. versionchanged :: 0.25.0
Returns
-------
DataFrame
See Also
--------
DataFrame.pivot : Pivot without aggregation that can handle
non-numeric data.
Examples
--------
>>> df = pd.DataFrame({"A": ["foo", "foo", "foo", "foo", "foo",
... "bar", "bar", "bar", "bar"],
... "B": ["one", "one", "one", "two", "two",
... "one", "one", "two", "two"],
... "C": ["small", "large", "large", "small",
... "small", "large", "small", "small",
... "large"],
... "D": [1, 2, 2, 3, 3, 4, 5, 6, 7],
... "E": [2, 4, 5, 5, 6, 6, 8, 9, 9]})
>>> df
A B C D E
0 foo one small 1 2
1 foo one large 2 4
2 foo one large 2 5
3 foo two small 3 5
4 foo two small 3 6
5 bar one large 4 6
6 bar one small 5 8
7 bar two small 6 9
8 bar two large 7 9
This first example aggregates values by taking the sum.
>>> table = pd.pivot_table(df, values='D', index=['A', 'B'],
... columns=['C'], aggfunc=np.sum)
>>> table
C large small
A B
bar one 4.0 5.0
two 7.0 6.0
foo one 4.0 1.0
two NaN 6.0
We can also fill missing values using the `fill_value` parameter.
>>> table = pd.pivot_table(df, values='D', index=['A', 'B'],
... columns=['C'], aggfunc=np.sum, fill_value=0)
>>> table
C large small
A B
bar one 4 5
two 7 6
foo one 4 1
two 0 6
The next example aggregates by taking the mean across multiple columns.
>>> table = pd.pivot_table(df, values=['D', 'E'], index=['A', 'C'],
... aggfunc={'D': np.mean,
... 'E': np.mean})
>>> table
D E
A C
bar large 5.500000 7.500000
small 5.500000 8.500000
foo large 2.000000 4.500000
small 2.333333 4.333333
We can also calculate multiple types of aggregations for any given
value column.
>>> table = pd.pivot_table(df, values=['D', 'E'], index=['A', 'C'],
... aggfunc={'D': np.mean,
... 'E': [min, max, np.mean]})
>>> table
D E
mean max mean min
A C
bar large 5.500000 9.0 7.500000 6.0
small 5.500000 9.0 8.500000 8.0
foo large 2.000000 5.0 4.500000 4.0
small 2.333333 6.0 4.333333 2.0
"""
@Substitution("")
@Appender(_shared_docs["pivot_table"])
def pivot_table(
self,
values=None,
index=None,
columns=None,
aggfunc="mean",
fill_value=None,
margins=False,
dropna=True,
margins_name="All",
observed=False,
):
from pandas.core.reshape.pivot import pivot_table
return pivot_table(
self,
values=values,
index=index,
columns=columns,
aggfunc=aggfunc,
fill_value=fill_value,
margins=margins,
dropna=dropna,
margins_name=margins_name,
observed=observed,
)
def stack(self, level=-1, dropna=True):
"""
Stack the prescribed level(s) from columns to index.
Return a reshaped DataFrame or Series having a multi-level
index with one or more new inner-most levels compared to the current
DataFrame. The new inner-most levels are created by pivoting the
columns of the current dataframe:
- if the columns have a single level, the output is a Series;
- if the columns have multiple levels, the new index
level(s) is (are) taken from the prescribed level(s) and
the output is a DataFrame.
The new index levels are sorted.
Parameters
----------
level : int, str, list, default -1
Level(s) to stack from the column axis onto the index
axis, defined as one index or label, or a list of indices
or labels.
dropna : bool, default True
Whether to drop rows in the resulting Frame/Series with
missing values. Stacking a column level onto the index
axis can create combinations of index and column values
that are missing from the original dataframe. See Examples
section.
Returns
-------
DataFrame or Series
Stacked dataframe or series.
See Also
--------
DataFrame.unstack : Unstack prescribed level(s) from index axis
onto column axis.
DataFrame.pivot : Reshape dataframe from long format to wide
format.
DataFrame.pivot_table : Create a spreadsheet-style pivot table
as a DataFrame.
Notes
-----
The function is named by analogy with a collection of books
being reorganized from being side by side on a horizontal
position (the columns of the dataframe) to being stacked
vertically on top of each other (in the index of the
dataframe).
Examples
--------
**Single level columns**
>>> df_single_level_cols = pd.DataFrame([[0, 1], [2, 3]],
... index=['cat', 'dog'],
... columns=['weight', 'height'])
Stacking a dataframe with a single level column axis returns a Series:
>>> df_single_level_cols
weight height
cat 0 1
dog 2 3
>>> df_single_level_cols.stack()
cat weight 0
height 1
dog weight 2
height 3
dtype: int64
**Multi level columns: simple case**
>>> multicol1 = pd.MultiIndex.from_tuples([('weight', 'kg'),
... ('weight', 'pounds')])
>>> df_multi_level_cols1 = pd.DataFrame([[1, 2], [2, 4]],
... index=['cat', 'dog'],
... columns=multicol1)
Stacking a dataframe with a multi-level column axis:
>>> df_multi_level_cols1
weight
kg pounds
cat 1 2
dog 2 4
>>> df_multi_level_cols1.stack()
weight
cat kg 1
pounds 2
dog kg 2
pounds 4
**Missing values**
>>> multicol2 = pd.MultiIndex.from_tuples([('weight', 'kg'),
... ('height', 'm')])
>>> df_multi_level_cols2 = pd.DataFrame([[1.0, 2.0], [3.0, 4.0]],
... index=['cat', 'dog'],
... columns=multicol2)
It is common to have missing values when stacking a dataframe
with multi-level columns, as the stacked dataframe typically
has more values than the original dataframe. Missing values
are filled with NaNs:
>>> df_multi_level_cols2
weight height
kg m
cat 1.0 2.0
dog 3.0 4.0
>>> df_multi_level_cols2.stack()
height weight
cat kg NaN 1.0
m 2.0 NaN
dog kg NaN 3.0
m 4.0 NaN
**Prescribing the level(s) to be stacked**
The first parameter controls which level or levels are stacked:
>>> df_multi_level_cols2.stack(0)
kg m
cat height NaN 2.0
weight 1.0 NaN
dog height NaN 4.0
weight 3.0 NaN
>>> df_multi_level_cols2.stack([0, 1])
cat height m 2.0
weight kg 1.0
dog height m 4.0
weight kg 3.0
dtype: float64
**Dropping missing values**
>>> df_multi_level_cols3 = pd.DataFrame([[None, 1.0], [2.0, 3.0]],
... index=['cat', 'dog'],
... columns=multicol2)
Note that rows where all values are missing are dropped by
default but this behaviour can be controlled via the dropna
keyword parameter:
>>> df_multi_level_cols3
weight height
kg m
cat NaN 1.0
dog 2.0 3.0
>>> df_multi_level_cols3.stack(dropna=False)
height weight
cat kg NaN NaN
m 1.0 NaN
dog kg NaN 2.0
m 3.0 NaN
>>> df_multi_level_cols3.stack(dropna=True)
height weight
cat m 1.0 NaN
dog kg NaN 2.0
m 3.0 NaN
"""
from pandas.core.reshape.reshape import stack, stack_multiple
if isinstance(level, (tuple, list)):
return stack_multiple(self, level, dropna=dropna)
else:
return stack(self, level, dropna=dropna)
def explode(self, column: Union[str, Tuple]) -> "DataFrame":
"""
Transform each element of a list-like to a row, replicating the
index values.
.. versionadded:: 0.25.0
Parameters
----------
column : str or tuple
Returns
-------
DataFrame
Exploded lists to rows of the subset columns;
index will be duplicated for these rows.
Raises
------
ValueError :
if columns of the frame are not unique.
See Also
--------
DataFrame.unstack : Pivot a level of the (necessarily hierarchical)
index labels
DataFrame.melt : Unpivot a DataFrame from wide format to long format
Series.explode : Explode a DataFrame from list-like columns to long format.
Notes
-----
This routine will explode list-likes including lists, tuples,
Series, and np.ndarray. The result dtype of the subset rows will
be object. Scalars will be returned unchanged. Empty list-likes will
result in a np.nan for that row.
Examples
--------
>>> df = pd.DataFrame({'A': [[1, 2, 3], 'foo', [], [3, 4]], 'B': 1})
>>> df
A B
0 [1, 2, 3] 1
1 foo 1
2 [] 1
3 [3, 4] 1
>>> df.explode('A')
A B
0 1 1
0 2 1
0 3 1
1 foo 1
2 NaN 1
3 3 1
3 4 1
"""
if not (is_scalar(column) or isinstance(column, tuple)):
raise ValueError("column must be a scalar")
if not self.columns.is_unique:
raise ValueError("columns must be unique")
result = self[column].explode()
return (
self.drop([column], axis=1)
.join(result)
.reindex(columns=self.columns, copy=False)
)
def unstack(self, level=-1, fill_value=None):
"""
Pivot a level of the (necessarily hierarchical) index labels, returning
a DataFrame having a new level of column labels whose inner-most level
consists of the pivoted index labels.
If the index is not a MultiIndex, the output will be a Series
(the analogue of stack when the columns are not a MultiIndex).
The level involved will automatically get sorted.
Parameters
----------
level : int, string, or list of these, default -1 (last level)
Level(s) of index to unstack, can pass level name
fill_value : replace NaN with this value if the unstack produces
missing values
Returns
-------
Series or DataFrame
See Also
--------
DataFrame.pivot : Pivot a table based on column values.
DataFrame.stack : Pivot a level of the column labels (inverse operation
from `unstack`).
Examples
--------
>>> index = pd.MultiIndex.from_tuples([('one', 'a'), ('one', 'b'),
... ('two', 'a'), ('two', 'b')])
>>> s = pd.Series(np.arange(1.0, 5.0), index=index)
>>> s
one a 1.0
b 2.0
two a 3.0
b 4.0
dtype: float64
>>> s.unstack(level=-1)
a b
one 1.0 2.0
two 3.0 4.0
>>> s.unstack(level=0)
one two
a 1.0 3.0
b 2.0 4.0
>>> df = s.unstack(level=0)
>>> df.unstack()
one a 1.0
b 2.0
two a 3.0
b 4.0
dtype: float64
"""
from pandas.core.reshape.reshape import unstack
return unstack(self, level, fill_value)
_shared_docs[
"melt"
] = """
Unpivot a DataFrame from wide format to long format, optionally
leaving identifier variables set.
This function is useful to massage a DataFrame into a format where one
or more columns are identifier variables (`id_vars`), while all other
columns, considered measured variables (`value_vars`), are "unpivoted" to
the row axis, leaving just two non-identifier columns, 'variable' and
'value'.
%(versionadded)s
Parameters
----------
frame : DataFrame
id_vars : tuple, list, or ndarray, optional
Column(s) to use as identifier variables.
value_vars : tuple, list, or ndarray, optional
Column(s) to unpivot. If not specified, uses all columns that
are not set as `id_vars`.
var_name : scalar
Name to use for the 'variable' column. If None it uses
``frame.columns.name`` or 'variable'.
value_name : scalar, default 'value'
Name to use for the 'value' column.
col_level : int or string, optional
If columns are a MultiIndex then use this level to melt.
Returns
-------
DataFrame
Unpivoted DataFrame.
See Also
--------
%(other)s
pivot_table
DataFrame.pivot
Series.explode
Examples
--------
>>> df = pd.DataFrame({'A': {0: 'a', 1: 'b', 2: 'c'},
... 'B': {0: 1, 1: 3, 2: 5},
... 'C': {0: 2, 1: 4, 2: 6}})
>>> df
A B C
0 a 1 2
1 b 3 4
2 c 5 6
>>> %(caller)sid_vars=['A'], value_vars=['B'])
A variable value
0 a B 1
1 b B 3
2 c B 5
>>> %(caller)sid_vars=['A'], value_vars=['B', 'C'])
A variable value
0 a B 1
1 b B 3
2 c B 5
3 a C 2
4 b C 4
5 c C 6
The names of 'variable' and 'value' columns can be customized:
>>> %(caller)sid_vars=['A'], value_vars=['B'],
... var_name='myVarname', value_name='myValname')
A myVarname myValname
0 a B 1
1 b B 3
2 c B 5
If you have multi-index columns:
>>> df.columns = [list('ABC'), list('DEF')]
>>> df
A B C
D E F
0 a 1 2
1 b 3 4
2 c 5 6
>>> %(caller)scol_level=0, id_vars=['A'], value_vars=['B'])
A variable value
0 a B 1
1 b B 3
2 c B 5
>>> %(caller)sid_vars=[('A', 'D')], value_vars=[('B', 'E')])
(A, D) variable_0 variable_1 value
0 a B E 1
1 b B E 3
2 c B E 5
"""
@Appender(
_shared_docs["melt"]
% dict(
caller="df.melt(", versionadded=".. versionadded:: 0.20.0\n", other="melt"
)
)
def melt(
self,
id_vars=None,
value_vars=None,
var_name=None,
value_name="value",
col_level=None,
):
from pandas.core.reshape.melt import melt
return melt(
self,
id_vars=id_vars,
value_vars=value_vars,
var_name=var_name,
value_name=value_name,
col_level=col_level,
)
# ----------------------------------------------------------------------
# Time series-related
def diff(self, periods=1, axis=0):
"""
First discrete difference of element.
Calculates the difference of a DataFrame element compared with another
element in the DataFrame (default is the element in the same column
of the previous row).
Parameters
----------
periods : int, default 1
Periods to shift for calculating difference, accepts negative
values.
axis : {0 or 'index', 1 or 'columns'}, default 0
Take difference over rows (0) or columns (1).
.. versionadded:: 0.16.1.
Returns
-------
DataFrame
See Also
--------
Series.diff: First discrete difference for a Series.
DataFrame.pct_change: Percent change over given number of periods.
DataFrame.shift: Shift index by desired number of periods with an
optional time freq.
Examples
--------
Difference with previous row
>>> df = pd.DataFrame({'a': [1, 2, 3, 4, 5, 6],
... 'b': [1, 1, 2, 3, 5, 8],
... 'c': [1, 4, 9, 16, 25, 36]})
>>> df
a b c
0 1 1 1
1 2 1 4
2 3 2 9
3 4 3 16
4 5 5 25
5 6 8 36
>>> df.diff()
a b c
0 NaN NaN NaN
1 1.0 0.0 3.0
2 1.0 1.0 5.0
3 1.0 1.0 7.0
4 1.0 2.0 9.0
5 1.0 3.0 11.0
Difference with previous column
>>> df.diff(axis=1)
a b c
0 NaN 0.0 0.0
1 NaN -1.0 3.0
2 NaN -1.0 7.0
3 NaN -1.0 13.0
4 NaN 0.0 20.0
5 NaN 2.0 28.0
Difference with 3rd previous row
>>> df.diff(periods=3)
a b c
0 NaN NaN NaN
1 NaN NaN NaN
2 NaN NaN NaN
3 3.0 2.0 15.0
4 3.0 4.0 21.0
5 3.0 6.0 27.0
Difference with following row
>>> df.diff(periods=-1)
a b c
0 -1.0 0.0 -3.0
1 -1.0 -1.0 -5.0
2 -1.0 -1.0 -7.0
3 -1.0 -2.0 -9.0
4 -1.0 -3.0 -11.0
5 NaN NaN NaN
"""
bm_axis = self._get_block_manager_axis(axis)
new_data = self._data.diff(n=periods, axis=bm_axis)
return self._constructor(new_data)
# ----------------------------------------------------------------------
# Function application
def _gotitem(
self,
key: Union[str, List[str]],
ndim: int,
subset: Optional[Union[Series, ABCDataFrame]] = None,
) -> Union[Series, ABCDataFrame]:
"""
Sub-classes to define. Return a sliced object.
Parameters
----------
key : string / list of selections
ndim : 1,2
requested ndim of result
subset : object, default None
subset to act on
"""
if subset is None:
subset = self
elif subset.ndim == 1: # is Series
return subset
# TODO: _shallow_copy(subset)?
return subset[key]
_agg_summary_and_see_also_doc = dedent(
"""
The aggregation operations are always performed over an axis, either the
index (default) or the column axis. This behavior is different from
`numpy` aggregation functions (`mean`, `median`, `prod`, `sum`, `std`,
`var`), where the default is to compute the aggregation of the flattened
array, e.g., ``numpy.mean(arr_2d)`` as opposed to
``numpy.mean(arr_2d, axis=0)``.
`agg` is an alias for `aggregate`. Use the alias.
See Also
--------
DataFrame.apply : Perform any type of operations.
DataFrame.transform : Perform transformation type operations.
core.groupby.GroupBy : Perform operations over groups.
core.resample.Resampler : Perform operations over resampled bins.
core.window.Rolling : Perform operations over rolling window.
core.window.Expanding : Perform operations over expanding window.
core.window.EWM : Perform operation over exponential weighted
window.
"""
)
_agg_examples_doc = dedent(
"""
Examples
--------
>>> df = pd.DataFrame([[1, 2, 3],
... [4, 5, 6],
... [7, 8, 9],
... [np.nan, np.nan, np.nan]],
... columns=['A', 'B', 'C'])
Aggregate these functions over the rows.
>>> df.agg(['sum', 'min'])
A B C
sum 12.0 15.0 18.0
min 1.0 2.0 3.0
Different aggregations per column.
>>> df.agg({'A' : ['sum', 'min'], 'B' : ['min', 'max']})
A B
max NaN 8.0
min 1.0 2.0
sum 12.0 NaN
Aggregate over the columns.
>>> df.agg("mean", axis="columns")
0 2.0
1 5.0
2 8.0
3 NaN
dtype: float64
"""
)
@Substitution(
see_also=_agg_summary_and_see_also_doc,
examples=_agg_examples_doc,
versionadded="\n.. versionadded:: 0.20.0\n",
**_shared_doc_kwargs
)
@Appender(_shared_docs["aggregate"])
def aggregate(self, func, axis=0, *args, **kwargs):
axis = self._get_axis_number(axis)
result = None
try:
result, how = self._aggregate(func, axis=axis, *args, **kwargs)
except TypeError:
pass
if result is None:
return self.apply(func, axis=axis, args=args, **kwargs)
return result
def _aggregate(self, arg, axis=0, *args, **kwargs):
if axis == 1:
# NDFrame.aggregate returns a tuple, and we need to transpose
# only result
result, how = self.T._aggregate(arg, *args, **kwargs)
result = result.T if result is not None else result
return result, how
return super()._aggregate(arg, *args, **kwargs)
agg = aggregate
@Appender(_shared_docs["transform"] % _shared_doc_kwargs)
def transform(self, func, axis=0, *args, **kwargs):
axis = self._get_axis_number(axis)
if axis == 1:
return self.T.transform(func, *args, **kwargs).T
return super().transform(func, *args, **kwargs)
def apply(
self,
func,
axis=0,
broadcast=None,
raw=False,
reduce=None,
result_type=None,
args=(),
**kwds
):
"""
Apply a function along an axis of the DataFrame.
Objects passed to the function are Series objects whose index is
either the DataFrame's index (``axis=0``) or the DataFrame's columns
(``axis=1``). By default (``result_type=None``), the final return type
is inferred from the return type of the applied function. Otherwise,
it depends on the `result_type` argument.
Parameters
----------
func : function
Function to apply to each column or row.
axis : {0 or 'index', 1 or 'columns'}, default 0
Axis along which the function is applied:
* 0 or 'index': apply function to each column.
* 1 or 'columns': apply function to each row.
broadcast : bool, optional
Only relevant for aggregation functions:
* ``False`` or ``None`` : returns a Series whose length is the
length of the index or the number of columns (based on the
`axis` parameter)
* ``True`` : results will be broadcast to the original shape
of the frame, the original index and columns will be retained.
.. deprecated:: 0.23.0
This argument will be removed in a future version, replaced
by result_type='broadcast'.
raw : bool, default False
* ``False`` : passes each row or column as a Series to the
function.
* ``True`` : the passed function will receive ndarray objects
instead.
If you are just applying a NumPy reduction function this will
achieve much better performance.
reduce : bool or None, default None
Try to apply reduction procedures. If the DataFrame is empty,
`apply` will use `reduce` to determine whether the result
should be a Series or a DataFrame. If ``reduce=None`` (the
default), `apply`'s return value will be guessed by calling
`func` on an empty Series
(note: while guessing, exceptions raised by `func` will be
ignored).
If ``reduce=True`` a Series will always be returned, and if
``reduce=False`` a DataFrame will always be returned.
.. deprecated:: 0.23.0
This argument will be removed in a future version, replaced
by ``result_type='reduce'``.
result_type : {'expand', 'reduce', 'broadcast', None}, default None
These only act when ``axis=1`` (columns):
* 'expand' : list-like results will be turned into columns.
* 'reduce' : returns a Series if possible rather than expanding
list-like results. This is the opposite of 'expand'.
* 'broadcast' : results will be broadcast to the original shape
of the DataFrame, the original index and columns will be
retained.
The default behaviour (None) depends on the return value of the
applied function: list-like results will be returned as a Series
of those. However if the apply function returns a Series these
are expanded to columns.
.. versionadded:: 0.23.0
args : tuple
Positional arguments to pass to `func` in addition to the
array/series.
**kwds
Additional keyword arguments to pass as keywords arguments to
`func`.
Returns
-------
Series or DataFrame
Result of applying ``func`` along the given axis of the
DataFrame.
See Also
--------
DataFrame.applymap: For elementwise operations.
DataFrame.aggregate: Only perform aggregating type operations.
DataFrame.transform: Only perform transforming type operations.
Notes
-----
In the current implementation apply calls `func` twice on the
first column/row to decide whether it can take a fast or slow
code path. This can lead to unexpected behavior if `func` has
side-effects, as they will take effect twice for the first
column/row.
Examples
--------
>>> df = pd.DataFrame([[4, 9]] * 3, columns=['A', 'B'])
>>> df
A B
0 4 9
1 4 9
2 4 9
Using a numpy universal function (in this case the same as
``np.sqrt(df)``):
>>> df.apply(np.sqrt)
A B
0 2.0 3.0
1 2.0 3.0
2 2.0 3.0
Using a reducing function on either axis
>>> df.apply(np.sum, axis=0)
A 12
B 27
dtype: int64
>>> df.apply(np.sum, axis=1)
0 13
1 13
2 13
dtype: int64
Returning a list-like will result in a Series
>>> df.apply(lambda x: [1, 2], axis=1)
0 [1, 2]
1 [1, 2]
2 [1, 2]
dtype: object
Passing result_type='expand' will expand list-like results
to columns of a Dataframe
>>> df.apply(lambda x: [1, 2], axis=1, result_type='expand')
0 1
0 1 2
1 1 2
2 1 2
Returning a Series inside the function is similar to passing
``result_type='expand'``. The resulting column names
will be the Series index.
>>> df.apply(lambda x: pd.Series([1, 2], index=['foo', 'bar']), axis=1)
foo bar
0 1 2
1 1 2
2 1 2
Passing ``result_type='broadcast'`` will ensure the same shape
result, whether list-like or scalar is returned by the function,
and broadcast it along the axis. The resulting column names will
be the originals.
>>> df.apply(lambda x: [1, 2], axis=1, result_type='broadcast')
A B
0 1 2
1 1 2
2 1 2
"""
from pandas.core.apply import frame_apply
op = frame_apply(
self,
func=func,
axis=axis,
broadcast=broadcast,
raw=raw,
reduce=reduce,
result_type=result_type,
args=args,
kwds=kwds,
)
return op.get_result()
def applymap(self, func):
"""
Apply a function to a Dataframe elementwise.
This method applies a function that accepts and returns a scalar
to every element of a DataFrame.
Parameters
----------
func : callable
Python function, returns a single value from a single value.
Returns
-------
DataFrame
Transformed DataFrame.
See Also
--------
DataFrame.apply : Apply a function along input axis of DataFrame.
Notes
-----
In the current implementation applymap calls `func` twice on the
first column/row to decide whether it can take a fast or slow
code path. This can lead to unexpected behavior if `func` has
side-effects, as they will take effect twice for the first
column/row.
Examples
--------
>>> df = pd.DataFrame([[1, 2.12], [3.356, 4.567]])
>>> df
0 1
0 1.000 2.120
1 3.356 4.567
>>> df.applymap(lambda x: len(str(x)))
0 1
0 3 4
1 5 5
Note that a vectorized version of `func` often exists, which will
be much faster. You could square each number elementwise.
>>> df.applymap(lambda x: x**2)
0 1
0 1.000000 4.494400
1 11.262736 20.857489
But it's better to avoid applymap in that case.
>>> df ** 2
0 1
0 1.000000 4.494400
1 11.262736 20.857489
"""
# if we have a dtype == 'M8[ns]', provide boxed values
def infer(x):
if x.empty:
return lib.map_infer(x, func)
return lib.map_infer(x.astype(object).values, func)
return self.apply(infer)
# ----------------------------------------------------------------------
# Merging / joining methods
def append(self, other, ignore_index=False, verify_integrity=False, sort=None):
"""
Append rows of `other` to the end of caller, returning a new object.
Columns in `other` that are not in the caller are added as new columns.
Parameters
----------
other : DataFrame or Series/dict-like object, or list of these
The data to append.
ignore_index : boolean, default False
If True, do not use the index labels.
verify_integrity : boolean, default False
If True, raise ValueError on creating index with duplicates.
sort : boolean, default None
Sort columns if the columns of `self` and `other` are not aligned.
The default sorting is deprecated and will change to not-sorting
in a future version of pandas. Explicitly pass ``sort=True`` to
silence the warning and sort. Explicitly pass ``sort=False`` to
silence the warning and not sort.
.. versionadded:: 0.23.0
Returns
-------
DataFrame
See Also
--------
concat : General function to concatenate DataFrame or Series objects.
Notes
-----
If a list of dict/series is passed and the keys are all contained in
the DataFrame's index, the order of the columns in the resulting
DataFrame will be unchanged.
Iteratively appending rows to a DataFrame can be more computationally
intensive than a single concatenate. A better solution is to append
those rows to a list and then concatenate the list with the original
DataFrame all at once.
Examples
--------
>>> df = pd.DataFrame([[1, 2], [3, 4]], columns=list('AB'))
>>> df
A B
0 1 2
1 3 4
>>> df2 = pd.DataFrame([[5, 6], [7, 8]], columns=list('AB'))
>>> df.append(df2)
A B
0 1 2
1 3 4
0 5 6
1 7 8
With `ignore_index` set to True:
>>> df.append(df2, ignore_index=True)
A B
0 1 2
1 3 4
2 5 6
3 7 8
The following, while not recommended methods for generating DataFrames,
show two ways to generate a DataFrame from multiple data sources.
Less efficient:
>>> df = pd.DataFrame(columns=['A'])
>>> for i in range(5):
... df = df.append({'A': i}, ignore_index=True)
>>> df
A
0 0
1 1
2 2
3 3
4 4
More efficient:
>>> pd.concat([pd.DataFrame([i], columns=['A']) for i in range(5)],
... ignore_index=True)
A
0 0
1 1
2 2
3 3
4 4
"""
if isinstance(other, (Series, dict)):
if isinstance(other, dict):
other = Series(other)
if other.name is None and not ignore_index:
raise TypeError(
"Can only append a Series if ignore_index=True"
" or if the Series has a name"
)
if other.name is None:
index = None
else:
# other must have the same index name as self, otherwise
# index name will be reset
index = Index([other.name], name=self.index.name)
idx_diff = other.index.difference(self.columns)
try:
combined_columns = self.columns.append(idx_diff)
except TypeError:
combined_columns = self.columns.astype(object).append(idx_diff)
other = other.reindex(combined_columns, copy=False)
other = DataFrame(
other.values.reshape((1, len(other))),
index=index,
columns=combined_columns,
)
other = other._convert(datetime=True, timedelta=True)
if not self.columns.equals(combined_columns):
self = self.reindex(columns=combined_columns)
elif isinstance(other, list) and not isinstance(other[0], DataFrame):
other = DataFrame(other)
if (self.columns.get_indexer(other.columns) >= 0).all():
other = other.reindex(columns=self.columns)
from pandas.core.reshape.concat import concat
if isinstance(other, (list, tuple)):
to_concat = [self] + other
else:
to_concat = [self, other]
return concat(
to_concat,
ignore_index=ignore_index,
verify_integrity=verify_integrity,
sort=sort,
)
def join(self, other, on=None, how="left", lsuffix="", rsuffix="", sort=False):
"""
Join columns of another DataFrame.
Join columns with `other` DataFrame either on index or on a key
column. Efficiently join multiple DataFrame objects by index at once by
passing a list.
Parameters
----------
other : DataFrame, Series, or list of DataFrame
Index should be similar to one of the columns in this one. If a
Series is passed, its name attribute must be set, and that will be
used as the column name in the resulting joined DataFrame.
on : str, list of str, or array-like, optional
Column or index level name(s) in the caller to join on the index
in `other`, otherwise joins index-on-index. If multiple
values given, the `other` DataFrame must have a MultiIndex. Can
pass an array as the join key if it is not already contained in
the calling DataFrame. Like an Excel VLOOKUP operation.
how : {'left', 'right', 'outer', 'inner'}, default 'left'
How to handle the operation of the two objects.
* left: use calling frame's index (or column if on is specified)
* right: use `other`'s index.
* outer: form union of calling frame's index (or column if on is
specified) with `other`'s index, and sort it.
lexicographically.
* inner: form intersection of calling frame's index (or column if
on is specified) with `other`'s index, preserving the order
of the calling's one.
lsuffix : str, default ''
Suffix to use from left frame's overlapping columns.
rsuffix : str, default ''
Suffix to use from right frame's overlapping columns.
sort : bool, default False
Order result DataFrame lexicographically by the join key. If False,
the order of the join key depends on the join type (how keyword).
Returns
-------
DataFrame
A dataframe containing columns from both the caller and `other`.
See Also
--------
DataFrame.merge : For column(s)-on-columns(s) operations.
Notes
-----
Parameters `on`, `lsuffix`, and `rsuffix` are not supported when
passing a list of `DataFrame` objects.
Support for specifying index levels as the `on` parameter was added
in version 0.23.0.
Examples
--------
>>> df = pd.DataFrame({'key': ['K0', 'K1', 'K2', 'K3', 'K4', 'K5'],
... 'A': ['A0', 'A1', 'A2', 'A3', 'A4', 'A5']})
>>> df
key A
0 K0 A0
1 K1 A1
2 K2 A2
3 K3 A3
4 K4 A4
5 K5 A5
>>> other = pd.DataFrame({'key': ['K0', 'K1', 'K2'],
... 'B': ['B0', 'B1', 'B2']})
>>> other
key B
0 K0 B0
1 K1 B1
2 K2 B2
Join DataFrames using their indexes.
>>> df.join(other, lsuffix='_caller', rsuffix='_other')
key_caller A key_other B
0 K0 A0 K0 B0
1 K1 A1 K1 B1
2 K2 A2 K2 B2
3 K3 A3 NaN NaN
4 K4 A4 NaN NaN
5 K5 A5 NaN NaN
If we want to join using the key columns, we need to set key to be
the index in both `df` and `other`. The joined DataFrame will have
key as its index.
>>> df.set_index('key').join(other.set_index('key'))
A B
key
K0 A0 B0
K1 A1 B1
K2 A2 B2
K3 A3 NaN
K4 A4 NaN
K5 A5 NaN
Another option to join using the key columns is to use the `on`
parameter. DataFrame.join always uses `other`'s index but we can use
any column in `df`. This method preserves the original DataFrame's
index in the result.
>>> df.join(other.set_index('key'), on='key')
key A B
0 K0 A0 B0
1 K1 A1 B1
2 K2 A2 B2
3 K3 A3 NaN
4 K4 A4 NaN
5 K5 A5 NaN
"""
# For SparseDataFrame's benefit
return self._join_compat(
other, on=on, how=how, lsuffix=lsuffix, rsuffix=rsuffix, sort=sort
)
def _join_compat(
self, other, on=None, how="left", lsuffix="", rsuffix="", sort=False
):
from pandas.core.reshape.merge import merge
from pandas.core.reshape.concat import concat
if isinstance(other, Series):
if other.name is None:
raise ValueError("Other Series must have a name")
other = DataFrame({other.name: other})
if isinstance(other, DataFrame):
return merge(
self,
other,
left_on=on,
how=how,
left_index=on is None,
right_index=True,
suffixes=(lsuffix, rsuffix),
sort=sort,
)
else:
if on is not None:
raise ValueError(
"Joining multiple DataFrames only supported" " for joining on index"
)
frames = [self] + list(other)
can_concat = all(df.index.is_unique for df in frames)
# join indexes only using concat
if can_concat:
if how == "left":
res = concat(frames, axis=1, join="outer", verify_integrity=True)
return res.reindex(self.index, copy=False)
else:
return concat(frames, axis=1, join=how, verify_integrity=True)
joined = frames[0]
for frame in frames[1:]:
joined = merge(
joined, frame, how=how, left_index=True, right_index=True
)
return joined
@Substitution("")
@Appender(_merge_doc, indents=2)
def merge(
self,
right,
how="inner",
on=None,
left_on=None,
right_on=None,
left_index=False,
right_index=False,
sort=False,
suffixes=("_x", "_y"),
copy=True,
indicator=False,
validate=None,
):
from pandas.core.reshape.merge import merge
return merge(
self,
right,
how=how,
on=on,
left_on=left_on,
right_on=right_on,
left_index=left_index,
right_index=right_index,
sort=sort,
suffixes=suffixes,
copy=copy,
indicator=indicator,
validate=validate,
)
def round(self, decimals=0, *args, **kwargs):
"""
Round a DataFrame to a variable number of decimal places.
Parameters
----------
decimals : int, dict, Series
Number of decimal places to round each column to. If an int is
given, round each column to the same number of places.
Otherwise dict and Series round to variable numbers of places.
Column names should be in the keys if `decimals` is a
dict-like, or in the index if `decimals` is a Series. Any
columns not included in `decimals` will be left as is. Elements
of `decimals` which are not columns of the input will be
ignored.
*args
Additional keywords have no effect but might be accepted for
compatibility with numpy.
**kwargs
Additional keywords have no effect but might be accepted for
compatibility with numpy.
Returns
-------
DataFrame
A DataFrame with the affected columns rounded to the specified
number of decimal places.
See Also
--------
numpy.around : Round a numpy array to the given number of decimals.
Series.round : Round a Series to the given number of decimals.
Examples
--------
>>> df = pd.DataFrame([(.21, .32), (.01, .67), (.66, .03), (.21, .18)],
... columns=['dogs', 'cats'])
>>> df
dogs cats
0 0.21 0.32
1 0.01 0.67
2 0.66 0.03
3 0.21 0.18
By providing an integer each column is rounded to the same number
of decimal places
>>> df.round(1)
dogs cats
0 0.2 0.3
1 0.0 0.7
2 0.7 0.0
3 0.2 0.2
With a dict, the number of places for specific columns can be
specified with the column names as key and the number of decimal
places as value
>>> df.round({'dogs': 1, 'cats': 0})
dogs cats
0 0.2 0.0
1 0.0 1.0
2 0.7 0.0
3 0.2 0.0
Using a Series, the number of places for specific columns can be
specified with the column names as index and the number of
decimal places as value
>>> decimals = pd.Series([0, 1], index=['cats', 'dogs'])
>>> df.round(decimals)
dogs cats
0 0.2 0.0
1 0.0 1.0
2 0.7 0.0
3 0.2 0.0
"""
from pandas.core.reshape.concat import concat
def _dict_round(df, decimals):
for col, vals in df.items():
try:
yield _series_round(vals, decimals[col])
except KeyError:
yield vals
def _series_round(s, decimals):
if is_integer_dtype(s) or is_float_dtype(s):
return s.round(decimals)
return s
nv.validate_round(args, kwargs)
if isinstance(decimals, (dict, Series)):
if isinstance(decimals, Series):
if not decimals.index.is_unique:
raise ValueError("Index of decimals must be unique")
new_cols = [col for col in _dict_round(self, decimals)]
elif is_integer(decimals):
# Dispatch to Series.round
new_cols = [_series_round(v, decimals) for _, v in self.items()]
else:
raise TypeError("decimals must be an integer, a dict-like or a " "Series")
if len(new_cols) > 0:
return self._constructor(
concat(new_cols, axis=1), index=self.index, columns=self.columns
)
else:
return self
# ----------------------------------------------------------------------
# Statistical methods, etc.
def corr(self, method="pearson", min_periods=1):
"""
Compute pairwise correlation of columns, excluding NA/null values.
Parameters
----------
method : {'pearson', 'kendall', 'spearman'} or callable
* pearson : standard correlation coefficient
* kendall : Kendall Tau correlation coefficient
* spearman : Spearman rank correlation
* callable: callable with input two 1d ndarrays
and returning a float. Note that the returned matrix from corr
will have 1 along the diagonals and will be symmetric
regardless of the callable's behavior
.. versionadded:: 0.24.0
min_periods : int, optional
Minimum number of observations required per pair of columns
to have a valid result. Currently only available for Pearson
and Spearman correlation.
Returns
-------
DataFrame
Correlation matrix.
See Also
--------
DataFrame.corrwith
Series.corr
Examples
--------
>>> def histogram_intersection(a, b):
... v = np.minimum(a, b).sum().round(decimals=1)
... return v
>>> df = pd.DataFrame([(.2, .3), (.0, .6), (.6, .0), (.2, .1)],
... columns=['dogs', 'cats'])
>>> df.corr(method=histogram_intersection)
dogs cats
dogs 1.0 0.3
cats 0.3 1.0
"""
numeric_df = self._get_numeric_data()
cols = numeric_df.columns
idx = cols.copy()
mat = numeric_df.values
if method == "pearson":
correl = libalgos.nancorr(ensure_float64(mat), minp=min_periods)
elif method == "spearman":
correl = libalgos.nancorr_spearman(ensure_float64(mat), minp=min_periods)
elif method == "kendall" or callable(method):
if min_periods is None:
min_periods = 1
mat = ensure_float64(mat).T
corrf = nanops.get_corr_func(method)
K = len(cols)
correl = np.empty((K, K), dtype=float)
mask = np.isfinite(mat)
for i, ac in enumerate(mat):
for j, bc in enumerate(mat):
if i > j:
continue
valid = mask[i] & mask[j]
if valid.sum() < min_periods:
c = np.nan
elif i == j:
c = 1.0
elif not valid.all():
c = corrf(ac[valid], bc[valid])
else:
c = corrf(ac, bc)
correl[i, j] = c
correl[j, i] = c
else:
raise ValueError(
"method must be either 'pearson', "
"'spearman', 'kendall', or a callable, "
"'{method}' was supplied".format(method=method)
)
return self._constructor(correl, index=idx, columns=cols)
def cov(self, min_periods=None):
"""
Compute pairwise covariance of columns, excluding NA/null values.
Compute the pairwise covariance among the series of a DataFrame.
The returned data frame is the `covariance matrix
<https://en.wikipedia.org/wiki/Covariance_matrix>`__ of the columns
of the DataFrame.
Both NA and null values are automatically excluded from the
calculation. (See the note below about bias from missing values.)
A threshold can be set for the minimum number of
observations for each value created. Comparisons with observations
below this threshold will be returned as ``NaN``.
This method is generally used for the analysis of time series data to
understand the relationship between different measures
across time.
Parameters
----------
min_periods : int, optional
Minimum number of observations required per pair of columns
to have a valid result.
Returns
-------
DataFrame
The covariance matrix of the series of the DataFrame.
See Also
--------
Series.cov : Compute covariance with another Series.
core.window.EWM.cov: Exponential weighted sample covariance.
core.window.Expanding.cov : Expanding sample covariance.
core.window.Rolling.cov : Rolling sample covariance.
Notes
-----
Returns the covariance matrix of the DataFrame's time series.
The covariance is normalized by N-1.
For DataFrames that have Series that are missing data (assuming that
data is `missing at random
<https://en.wikipedia.org/wiki/Missing_data#Missing_at_random>`__)
the returned covariance matrix will be an unbiased estimate
of the variance and covariance between the member Series.
However, for many applications this estimate may not be acceptable
because the estimate covariance matrix is not guaranteed to be positive
semi-definite. This could lead to estimate correlations having
absolute values which are greater than one, and/or a non-invertible
covariance matrix. See `Estimation of covariance matrices
<http://en.wikipedia.org/w/index.php?title=Estimation_of_covariance_
matrices>`__ for more details.
Examples
--------
>>> df = pd.DataFrame([(1, 2), (0, 3), (2, 0), (1, 1)],
... columns=['dogs', 'cats'])
>>> df.cov()
dogs cats
dogs 0.666667 -1.000000
cats -1.000000 1.666667
>>> np.random.seed(42)
>>> df = pd.DataFrame(np.random.randn(1000, 5),
... columns=['a', 'b', 'c', 'd', 'e'])
>>> df.cov()
a b c d e
a 0.998438 -0.020161 0.059277 -0.008943 0.014144
b -0.020161 1.059352 -0.008543 -0.024738 0.009826
c 0.059277 -0.008543 1.010670 -0.001486 -0.000271
d -0.008943 -0.024738 -0.001486 0.921297 -0.013692
e 0.014144 0.009826 -0.000271 -0.013692 0.977795
**Minimum number of periods**
This method also supports an optional ``min_periods`` keyword
that specifies the required minimum number of non-NA observations for
each column pair in order to have a valid result:
>>> np.random.seed(42)
>>> df = pd.DataFrame(np.random.randn(20, 3),
... columns=['a', 'b', 'c'])
>>> df.loc[df.index[:5], 'a'] = np.nan
>>> df.loc[df.index[5:10], 'b'] = np.nan
>>> df.cov(min_periods=12)
a b c
a 0.316741 NaN -0.150812
b NaN 1.248003 0.191417
c -0.150812 0.191417 0.895202
"""
numeric_df = self._get_numeric_data()
cols = numeric_df.columns
idx = cols.copy()
mat = numeric_df.values
if notna(mat).all():
if min_periods is not None and min_periods > len(mat):
baseCov = np.empty((mat.shape[1], mat.shape[1]))
baseCov.fill(np.nan)
else:
baseCov = np.cov(mat.T)
baseCov = baseCov.reshape((len(cols), len(cols)))
else:
baseCov = libalgos.nancorr(ensure_float64(mat), cov=True, minp=min_periods)
return self._constructor(baseCov, index=idx, columns=cols)
def corrwith(self, other, axis=0, drop=False, method="pearson"):
"""
Compute pairwise correlation between rows or columns of DataFrame
with rows or columns of Series or DataFrame. DataFrames are first
aligned along both axes before computing the correlations.
Parameters
----------
other : DataFrame, Series
Object with which to compute correlations.
axis : {0 or 'index', 1 or 'columns'}, default 0
0 or 'index' to compute column-wise, 1 or 'columns' for row-wise.
drop : bool, default False
Drop missing indices from result.
method : {'pearson', 'kendall', 'spearman'} or callable
* pearson : standard correlation coefficient
* kendall : Kendall Tau correlation coefficient
* spearman : Spearman rank correlation
* callable: callable with input two 1d ndarrays
and returning a float
.. versionadded:: 0.24.0
Returns
-------
Series
Pairwise correlations.
See Also
--------
DataFrame.corr
"""
axis = self._get_axis_number(axis)
this = self._get_numeric_data()
if isinstance(other, Series):
return this.apply(lambda x: other.corr(x, method=method), axis=axis)
other = other._get_numeric_data()
left, right = this.align(other, join="inner", copy=False)
if axis == 1:
left = left.T
right = right.T
if method == "pearson":
# mask missing values
left = left + right * 0
right = right + left * 0
# demeaned data
ldem = left - left.mean()
rdem = right - right.mean()
num = (ldem * rdem).sum()
dom = (left.count() - 1) * left.std() * right.std()
correl = num / dom
elif method in ["kendall", "spearman"] or callable(method):
def c(x):
return nanops.nancorr(x[0], x[1], method=method)
correl = Series(
map(c, zip(left.values.T, right.values.T)), index=left.columns
)
else:
raise ValueError(
"Invalid method {method} was passed, "
"valid methods are: 'pearson', 'kendall', "
"'spearman', or callable".format(method=method)
)
if not drop:
# Find non-matching labels along the given axis
# and append missing correlations (GH 22375)
raxis = 1 if axis == 0 else 0
result_index = this._get_axis(raxis).union(other._get_axis(raxis))
idx_diff = result_index.difference(correl.index)
if len(idx_diff) > 0:
correl = correl.append(Series([np.nan] * len(idx_diff), index=idx_diff))
return correl
# ----------------------------------------------------------------------
# ndarray-like stats methods
def count(self, axis=0, level=None, numeric_only=False):
"""
Count non-NA cells for each column or row.
The values `None`, `NaN`, `NaT`, and optionally `numpy.inf` (depending
on `pandas.options.mode.use_inf_as_na`) are considered NA.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
If 0 or 'index' counts are generated for each column.
If 1 or 'columns' counts are generated for each **row**.
level : int or str, optional
If the axis is a `MultiIndex` (hierarchical), count along a
particular `level`, collapsing into a `DataFrame`.
A `str` specifies the level name.
numeric_only : bool, default False
Include only `float`, `int` or `boolean` data.
Returns
-------
Series or DataFrame
For each column/row the number of non-NA/null entries.
If `level` is specified returns a `DataFrame`.
See Also
--------
Series.count: Number of non-NA elements in a Series.
DataFrame.shape: Number of DataFrame rows and columns (including NA
elements).
DataFrame.isna: Boolean same-sized DataFrame showing places of NA
elements.
Examples
--------
Constructing DataFrame from a dictionary:
>>> df = pd.DataFrame({"Person":
... ["John", "Myla", "Lewis", "John", "Myla"],
... "Age": [24., np.nan, 21., 33, 26],
... "Single": [False, True, True, True, False]})
>>> df
Person Age Single
0 John 24.0 False
1 Myla NaN True
2 Lewis 21.0 True
3 John 33.0 True
4 Myla 26.0 False
Notice the uncounted NA values:
>>> df.count()
Person 5
Age 4
Single 5
dtype: int64
Counts for each **row**:
>>> df.count(axis='columns')
0 3
1 2
2 3
3 3
4 3
dtype: int64
Counts for one level of a `MultiIndex`:
>>> df.set_index(["Person", "Single"]).count(level="Person")
Age
Person
John 2
Lewis 1
Myla 1
"""
axis = self._get_axis_number(axis)
if level is not None:
return self._count_level(level, axis=axis, numeric_only=numeric_only)
if numeric_only:
frame = self._get_numeric_data()
else:
frame = self
# GH #423
if len(frame._get_axis(axis)) == 0:
result = Series(0, index=frame._get_agg_axis(axis))
else:
if frame._is_mixed_type or frame._data.any_extension_types:
# the or any_extension_types is really only hit for single-
# column frames with an extension array
result = notna(frame).sum(axis=axis)
else:
# GH13407
series_counts = notna(frame).sum(axis=axis)
counts = series_counts.values
result = Series(counts, index=frame._get_agg_axis(axis))
return result.astype("int64")
def _count_level(self, level, axis=0, numeric_only=False):
if numeric_only:
frame = self._get_numeric_data()
else:
frame = self
count_axis = frame._get_axis(axis)
agg_axis = frame._get_agg_axis(axis)
if not isinstance(count_axis, MultiIndex):
raise TypeError(
"Can only count levels on hierarchical "
"{ax}.".format(ax=self._get_axis_name(axis))
)
if frame._is_mixed_type:
# Since we have mixed types, calling notna(frame.values) might
# upcast everything to object
mask = notna(frame).values
else:
# But use the speedup when we have homogeneous dtypes
mask = notna(frame.values)
if axis == 1:
# We're transposing the mask rather than frame to avoid potential
# upcasts to object, which induces a ~20x slowdown
mask = mask.T
if isinstance(level, str):
level = count_axis._get_level_number(level)
level_index = count_axis.levels[level]
level_codes = ensure_int64(count_axis.codes[level])
counts = lib.count_level_2d(mask, level_codes, len(level_index), axis=0)
result = DataFrame(counts, index=level_index, columns=agg_axis)
if axis == 1:
# Undo our earlier transpose
return result.T
else:
return result
def _reduce(
self, op, name, axis=0, skipna=True, numeric_only=None, filter_type=None, **kwds
):
if axis is None and filter_type == "bool":
labels = None
constructor = None
else:
# TODO: Make other agg func handle axis=None properly
axis = self._get_axis_number(axis)
labels = self._get_agg_axis(axis)
constructor = self._constructor
def f(x):
return op(x, axis=axis, skipna=skipna, **kwds)
# exclude timedelta/datetime unless we are uniform types
if (
axis == 1
and self._is_datelike_mixed_type
and (
not self._is_homogeneous_type
and not is_datetime64tz_dtype(self.dtypes[0])
)
):
numeric_only = True
if numeric_only is None:
try:
values = self.values
result = f(values)
if filter_type == "bool" and is_object_dtype(values) and axis is None:
# work around https://github.com/numpy/numpy/issues/10489
# TODO: combine with hasattr(result, 'dtype') further down
# hard since we don't have `values` down there.
result = np.bool_(result)
except Exception as e:
# try by-column first
if filter_type is None and axis == 0:
try:
# this can end up with a non-reduction
# but not always. if the types are mixed
# with datelike then need to make sure a series
# we only end up here if we have not specified
# numeric_only and yet we have tried a
# column-by-column reduction, where we have mixed type.
# So let's just do what we can
from pandas.core.apply import frame_apply
opa = frame_apply(
self, func=f, result_type="expand", ignore_failures=True
)
result = opa.get_result()
if result.ndim == self.ndim:
result = result.iloc[0]
return result
except Exception:
pass
if filter_type is None or filter_type == "numeric":
data = self._get_numeric_data()
elif filter_type == "bool":
data = self._get_bool_data()
else: # pragma: no cover
e = NotImplementedError(
"Handling exception with filter_type {f} not"
"implemented.".format(f=filter_type)
)
raise_with_traceback(e)
with np.errstate(all="ignore"):
result = f(data.values)
labels = data._get_agg_axis(axis)
else:
if numeric_only:
if filter_type is None or filter_type == "numeric":
data = self._get_numeric_data()
elif filter_type == "bool":
# GH 25101, # GH 24434
data = self._get_bool_data() if axis == 0 else self
else: # pragma: no cover
msg = (
"Generating numeric_only data with filter_type {f}"
"not supported.".format(f=filter_type)
)
raise NotImplementedError(msg)
values = data.values
labels = data._get_agg_axis(axis)
else:
values = self.values
result = f(values)
if hasattr(result, "dtype") and is_object_dtype(result.dtype):
try:
if filter_type is None or filter_type == "numeric":
result = result.astype(np.float64)
elif filter_type == "bool" and notna(result).all():
result = result.astype(np.bool_)
except (ValueError, TypeError):
# try to coerce to the original dtypes item by item if we can
if axis == 0:
result = coerce_to_dtypes(result, self.dtypes)
if constructor is not None:
result = Series(result, index=labels)
return result
def nunique(self, axis=0, dropna=True):
"""
Count distinct observations over requested axis.
Return Series with number of distinct observations. Can ignore NaN
values.
.. versionadded:: 0.20.0
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to use. 0 or 'index' for row-wise, 1 or 'columns' for
column-wise.
dropna : bool, default True
Don't include NaN in the counts.
Returns
-------
Series
See Also
--------
Series.nunique: Method nunique for Series.
DataFrame.count: Count non-NA cells for each column or row.
Examples
--------
>>> df = pd.DataFrame({'A': [1, 2, 3], 'B': [1, 1, 1]})
>>> df.nunique()
A 3
B 1
dtype: int64
>>> df.nunique(axis=1)
0 1
1 2
2 2
dtype: int64
"""
return self.apply(Series.nunique, axis=axis, dropna=dropna)
def idxmin(self, axis=0, skipna=True):
"""
Return index of first occurrence of minimum over requested axis.
NA/null values are excluded.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
0 or 'index' for row-wise, 1 or 'columns' for column-wise
skipna : boolean, default True
Exclude NA/null values. If an entire row/column is NA, the result
will be NA.
Returns
-------
Series
Indexes of minima along the specified axis.
Raises
------
ValueError
* If the row/column is empty
See Also
--------
Series.idxmin
Notes
-----
This method is the DataFrame version of ``ndarray.argmin``.
"""
axis = self._get_axis_number(axis)
indices = nanops.nanargmin(self.values, axis=axis, skipna=skipna)
index = self._get_axis(axis)
result = [index[i] if i >= 0 else np.nan for i in indices]
return Series(result, index=self._get_agg_axis(axis))
def idxmax(self, axis=0, skipna=True):
"""
Return index of first occurrence of maximum over requested axis.
NA/null values are excluded.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
0 or 'index' for row-wise, 1 or 'columns' for column-wise
skipna : boolean, default True
Exclude NA/null values. If an entire row/column is NA, the result
will be NA.
Returns
-------
Series
Indexes of maxima along the specified axis.
Raises
------
ValueError
* If the row/column is empty
See Also
--------
Series.idxmax
Notes
-----
This method is the DataFrame version of ``ndarray.argmax``.
"""
axis = self._get_axis_number(axis)
indices = nanops.nanargmax(self.values, axis=axis, skipna=skipna)
index = self._get_axis(axis)
result = [index[i] if i >= 0 else np.nan for i in indices]
return Series(result, index=self._get_agg_axis(axis))
def _get_agg_axis(self, axis_num):
"""
Let's be explicit about this.
"""
if axis_num == 0:
return self.columns
elif axis_num == 1:
return self.index
else:
raise ValueError("Axis must be 0 or 1 (got %r)" % axis_num)
def mode(self, axis=0, numeric_only=False, dropna=True):
"""
Get the mode(s) of each element along the selected axis.
The mode of a set of values is the value that appears most often.
It can be multiple values.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to iterate over while searching for the mode:
* 0 or 'index' : get mode of each column
* 1 or 'columns' : get mode of each row
numeric_only : bool, default False
If True, only apply to numeric columns.
dropna : bool, default True
Don't consider counts of NaN/NaT.
.. versionadded:: 0.24.0
Returns
-------
DataFrame
The modes of each column or row.
See Also
--------
Series.mode : Return the highest frequency value in a Series.
Series.value_counts : Return the counts of values in a Series.
Examples
--------
>>> df = pd.DataFrame([('bird', 2, 2),
... ('mammal', 4, np.nan),
... ('arthropod', 8, 0),
... ('bird', 2, np.nan)],
... index=('falcon', 'horse', 'spider', 'ostrich'),
... columns=('species', 'legs', 'wings'))
>>> df
species legs wings
falcon bird 2 2.0
horse mammal 4 NaN
spider arthropod 8 0.0
ostrich bird 2 NaN
By default, missing values are not considered, and the mode of wings
are both 0 and 2. The second row of species and legs contains ``NaN``,
because they have only one mode, but the DataFrame has two rows.
>>> df.mode()
species legs wings
0 bird 2.0 0.0
1 NaN NaN 2.0
Setting ``dropna=False`` ``NaN`` values are considered and they can be
the mode (like for wings).
>>> df.mode(dropna=False)
species legs wings
0 bird 2 NaN
Setting ``numeric_only=True``, only the mode of numeric columns is
computed, and columns of other types are ignored.
>>> df.mode(numeric_only=True)
legs wings
0 2.0 0.0
1 NaN 2.0
To compute the mode over columns and not rows, use the axis parameter:
>>> df.mode(axis='columns', numeric_only=True)
0 1
falcon 2.0 NaN
horse 4.0 NaN
spider 0.0 8.0
ostrich 2.0 NaN
"""
data = self if not numeric_only else self._get_numeric_data()
def f(s):
return s.mode(dropna=dropna)
return data.apply(f, axis=axis)
def quantile(self, q=0.5, axis=0, numeric_only=True, interpolation="linear"):
"""
Return values at the given quantile over requested axis.
Parameters
----------
q : float or array-like, default 0.5 (50% quantile)
Value between 0 <= q <= 1, the quantile(s) to compute.
axis : {0, 1, 'index', 'columns'} (default 0)
Equals 0 or 'index' for row-wise, 1 or 'columns' for column-wise.
numeric_only : bool, default True
If False, the quantile of datetime and timedelta data will be
computed as well.
interpolation : {'linear', 'lower', 'higher', 'midpoint', 'nearest'}
This optional parameter specifies the interpolation method to use,
when the desired quantile lies between two data points `i` and `j`:
* linear: `i + (j - i) * fraction`, where `fraction` is the
fractional part of the index surrounded by `i` and `j`.
* lower: `i`.
* higher: `j`.
* nearest: `i` or `j` whichever is nearest.
* midpoint: (`i` + `j`) / 2.
Returns
-------
Series or DataFrame
If ``q`` is an array, a DataFrame will be returned where the
index is ``q``, the columns are the columns of self, and the
values are the quantiles.
If ``q`` is a float, a Series will be returned where the
index is the columns of self and the values are the quantiles.
See Also
--------
core.window.Rolling.quantile: Rolling quantile.
numpy.percentile: Numpy function to compute the percentile.
Examples
--------
>>> df = pd.DataFrame(np.array([[1, 1], [2, 10], [3, 100], [4, 100]]),
... columns=['a', 'b'])
>>> df.quantile(.1)
a 1.3
b 3.7
Name: 0.1, dtype: float64
>>> df.quantile([.1, .5])
a b
0.1 1.3 3.7
0.5 2.5 55.0
Specifying `numeric_only=False` will also compute the quantile of
datetime and timedelta data.
>>> df = pd.DataFrame({'A': [1, 2],
... 'B': [pd.Timestamp('2010'),
... pd.Timestamp('2011')],
... 'C': [pd.Timedelta('1 days'),
... pd.Timedelta('2 days')]})
>>> df.quantile(0.5, numeric_only=False)
A 1.5
B 2010-07-02 12:00:00
C 1 days 12:00:00
Name: 0.5, dtype: object
"""
self._check_percentile(q)
data = self._get_numeric_data() if numeric_only else self
axis = self._get_axis_number(axis)
is_transposed = axis == 1
if is_transposed:
data = data.T
result = data._data.quantile(
qs=q, axis=1, interpolation=interpolation, transposed=is_transposed
)
if result.ndim == 2:
result = self._constructor(result)
else:
result = self._constructor_sliced(result, name=q)
if is_transposed:
result = result.T
return result
def to_timestamp(self, freq=None, how="start", axis=0, copy=True):
"""
Cast to DatetimeIndex of timestamps, at *beginning* of period.
Parameters
----------
freq : str, default frequency of PeriodIndex
Desired frequency.
how : {'s', 'e', 'start', 'end'}
Convention for converting period to timestamp; start of period
vs. end.
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to convert (the index by default).
copy : bool, default True
If False then underlying input data is not copied.
Returns
-------
DataFrame with DatetimeIndex
"""
new_data = self._data
if copy:
new_data = new_data.copy()
axis = self._get_axis_number(axis)
if axis == 0:
new_data.set_axis(1, self.index.to_timestamp(freq=freq, how=how))
elif axis == 1:
new_data.set_axis(0, self.columns.to_timestamp(freq=freq, how=how))
else: # pragma: no cover
raise AssertionError("Axis must be 0 or 1. Got {ax!s}".format(ax=axis))
return self._constructor(new_data)
def to_period(self, freq=None, axis=0, copy=True):
"""
Convert DataFrame from DatetimeIndex to PeriodIndex with desired
frequency (inferred from index if not passed).
Parameters
----------
freq : str, default
Frequency of the PeriodIndex.
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to convert (the index by default).
copy : bool, default True
If False then underlying input data is not copied.
Returns
-------
TimeSeries with PeriodIndex
"""
new_data = self._data
if copy:
new_data = new_data.copy()
axis = self._get_axis_number(axis)
if axis == 0:
new_data.set_axis(1, self.index.to_period(freq=freq))
elif axis == 1:
new_data.set_axis(0, self.columns.to_period(freq=freq))
else: # pragma: no cover
raise AssertionError("Axis must be 0 or 1. Got {ax!s}".format(ax=axis))
return self._constructor(new_data)
def isin(self, values):
"""
Whether each element in the DataFrame is contained in values.
Parameters
----------
values : iterable, Series, DataFrame or dict
The result will only be true at a location if all the
labels match. If `values` is a Series, that's the index. If
`values` is a dict, the keys must be the column names,
which must match. If `values` is a DataFrame,
then both the index and column labels must match.
Returns
-------
DataFrame
DataFrame of booleans showing whether each element in the DataFrame
is contained in values.
See Also
--------
DataFrame.eq: Equality test for DataFrame.
Series.isin: Equivalent method on Series.
Series.str.contains: Test if pattern or regex is contained within a
string of a Series or Index.
Examples
--------
>>> df = pd.DataFrame({'num_legs': [2, 4], 'num_wings': [2, 0]},
... index=['falcon', 'dog'])
>>> df
num_legs num_wings
falcon 2 2
dog 4 0
When ``values`` is a list check whether every value in the DataFrame
is present in the list (which animals have 0 or 2 legs or wings)
>>> df.isin([0, 2])
num_legs num_wings
falcon True True
dog False True
When ``values`` is a dict, we can pass values to check for each
column separately:
>>> df.isin({'num_wings': [0, 3]})
num_legs num_wings
falcon False False
dog False True
When ``values`` is a Series or DataFrame the index and column must
match. Note that 'falcon' does not match based on the number of legs
in df2.
>>> other = pd.DataFrame({'num_legs': [8, 2], 'num_wings': [0, 2]},
... index=['spider', 'falcon'])
>>> df.isin(other)
num_legs num_wings
falcon True True
dog False False
"""
if isinstance(values, dict):
from pandas.core.reshape.concat import concat
values = collections.defaultdict(list, values)
return concat(
(
self.iloc[:, [i]].isin(values[col])
for i, col in enumerate(self.columns)
),
axis=1,
)
elif isinstance(values, Series):
if not values.index.is_unique:
raise ValueError("cannot compute isin with " "a duplicate axis.")
return self.eq(values.reindex_like(self), axis="index")
elif isinstance(values, DataFrame):
if not (values.columns.is_unique and values.index.is_unique):
raise ValueError("cannot compute isin with " "a duplicate axis.")
return self.eq(values.reindex_like(self))
else:
if not is_list_like(values):
raise TypeError(
"only list-like or dict-like objects are "
"allowed to be passed to DataFrame.isin(), "
"you passed a "
"{0!r}".format(type(values).__name__)
)
return DataFrame(
algorithms.isin(self.values.ravel(), values).reshape(self.shape),
self.index,
self.columns,
)
# ----------------------------------------------------------------------
# Add plotting methods to DataFrame
plot = CachedAccessor("plot", pandas.plotting.PlotAccessor)
hist = pandas.plotting.hist_frame
boxplot = pandas.plotting.boxplot_frame
sparse = CachedAccessor("sparse", SparseFrameAccessor)
DataFrame._setup_axes(
["index", "columns"],
info_axis=1,
stat_axis=0,
axes_are_reversed=True,
aliases={"rows": 0},
docs={
"index": "The index (row labels) of the DataFrame.",
"columns": "The column labels of the DataFrame.",
},
)
DataFrame._add_numeric_operations()
DataFrame._add_series_or_dataframe_operations()
ops.add_flex_arithmetic_methods(DataFrame)
ops.add_special_arithmetic_methods(DataFrame)
def _from_nested_dict(data):
# TODO: this should be seriously cythonized
new_data = OrderedDict()
for index, s in data.items():
for col, v in s.items():
new_data[col] = new_data.get(col, OrderedDict())
new_data[col][index] = v
return new_data
def _put_str(s, space):
return "{s}".format(s=s)[:space].ljust(space)
"""
DataFrame
---------
An efficient 2D container for potentially mixed-type time series or other
labeled data series.
Similar to its R counterpart, data.frame, except providing automatic data
alignment and a host of useful data manipulation methods having to do with the
labeling information
"""
import collections
from collections import OrderedDict, abc
import functools
from io import StringIO
import itertools
import sys
from textwrap import dedent
from typing import FrozenSet, List, Optional, Set, Tuple, Type, Union
import warnings
import numpy as np
import numpy.ma as ma
from pandas._config import get_option
from pandas._libs import algos as libalgos, lib
from pandas.compat import PY36, raise_with_traceback
from pandas.compat.numpy import function as nv
from pandas.util._decorators import (
Appender,
Substitution,
deprecate_kwarg,
rewrite_axis_style_signature,
)
from pandas.util._validators import validate_axis_style_args, validate_bool_kwarg
from pandas.core.dtypes.cast import (
cast_scalar_to_array,
coerce_to_dtypes,
find_common_type,
infer_dtype_from_scalar,
invalidate_string_dtypes,
maybe_cast_to_datetime,
maybe_convert_platform,
maybe_downcast_to_dtype,
maybe_infer_to_datetimelike,
maybe_upcast,
maybe_upcast_putmask,
)
from pandas.core.dtypes.common import (
ensure_float64,
ensure_int64,
ensure_platform_int,
infer_dtype_from_object,
is_bool_dtype,
is_datetime64_any_dtype,
is_datetime64tz_dtype,
is_dict_like,
is_dtype_equal,
is_extension_array_dtype,
is_extension_type,
is_float_dtype,
is_hashable,
is_integer,
is_integer_dtype,
is_iterator,
is_list_like,
is_named_tuple,
is_nested_list_like,
is_object_dtype,
is_scalar,
is_sequence,
needs_i8_conversion,
)
from pandas.core.dtypes.generic import (
ABCDataFrame,
ABCIndexClass,
ABCMultiIndex,
ABCSeries,
)
from pandas.core.dtypes.missing import isna, notna
from pandas.core import algorithms, common as com, nanops, ops
from pandas.core.accessor import CachedAccessor
from pandas.core.arrays import Categorical, ExtensionArray
from pandas.core.arrays.datetimelike import DatetimeLikeArrayMixin as DatetimeLikeArray
from pandas.core.arrays.sparse import SparseFrameAccessor
from pandas.core.generic import NDFrame, _shared_docs
from pandas.core.index import (
Index,
MultiIndex,
ensure_index,
ensure_index_from_sequences,
)
from pandas.core.indexes import base as ibase
from pandas.core.indexes.datetimes import DatetimeIndex
from pandas.core.indexes.period import PeriodIndex
from pandas.core.indexing import (
check_bool_indexer,
convert_to_index_sliceable,
maybe_droplevels,
)
from pandas.core.internals import BlockManager
from pandas.core.internals.construction import (
arrays_to_mgr,
get_names_from_index,
init_dict,
init_ndarray,
masked_rec_array_to_mgr,
reorder_arrays,
sanitize_index,
to_arrays,
)
from pandas.core.series import Series
from pandas.io.formats import console, format as fmt
from pandas.io.formats.printing import pprint_thing
import pandas.plotting
# ---------------------------------------------------------------------
# Docstring templates
_shared_doc_kwargs = dict(
axes="index, columns",
klass="DataFrame",
axes_single_arg="{0 or 'index', 1 or 'columns'}",
axis="""axis : {0 or 'index', 1 or 'columns'}, default 0
If 0 or 'index': apply function to each column.
If 1 or 'columns': apply function to each row.""",
optional_by="""
by : str or list of str
Name or list of names to sort by.
- if `axis` is 0 or `'index'` then `by` may contain index
levels and/or column labels
- if `axis` is 1 or `'columns'` then `by` may contain column
levels and/or index labels
.. versionchanged:: 0.23.0
Allow specifying index or column level names.""",
versionadded_to_excel="",
optional_labels="""labels : array-like, optional
New labels / index to conform the axis specified by 'axis' to.""",
optional_axis="""axis : int or str, optional
Axis to target. Can be either the axis name ('index', 'columns')
or number (0, 1).""",
)
_numeric_only_doc = """numeric_only : boolean, default None
Include only float, int, boolean data. If None, will attempt to use
everything, then use only numeric data
"""
_merge_doc = """
Merge DataFrame or named Series objects with a database-style join.
The join is done on columns or indexes. If joining columns on
columns, the DataFrame indexes *will be ignored*. Otherwise if joining indexes
on indexes or indexes on a column or columns, the index will be passed on.
Parameters
----------%s
right : DataFrame or named Series
Object to merge with.
how : {'left', 'right', 'outer', 'inner'}, default 'inner'
Type of merge to be performed.
* left: use only keys from left frame, similar to a SQL left outer join;
preserve key order.
* right: use only keys from right frame, similar to a SQL right outer join;
preserve key order.
* outer: use union of keys from both frames, similar to a SQL full outer
join; sort keys lexicographically.
* inner: use intersection of keys from both frames, similar to a SQL inner
join; preserve the order of the left keys.
on : label or list
Column or index level names to join on. These must be found in both
DataFrames. If `on` is None and not merging on indexes then this defaults
to the intersection of the columns in both DataFrames.
left_on : label or list, or array-like
Column or index level names to join on in the left DataFrame. Can also
be an array or list of arrays of the length of the left DataFrame.
These arrays are treated as if they are columns.
right_on : label or list, or array-like
Column or index level names to join on in the right DataFrame. Can also
be an array or list of arrays of the length of the right DataFrame.
These arrays are treated as if they are columns.
left_index : bool, default False
Use the index from the left DataFrame as the join key(s). If it is a
MultiIndex, the number of keys in the other DataFrame (either the index
or a number of columns) must match the number of levels.
right_index : bool, default False
Use the index from the right DataFrame as the join key. Same caveats as
left_index.
sort : bool, default False
Sort the join keys lexicographically in the result DataFrame. If False,
the order of the join keys depends on the join type (how keyword).
suffixes : tuple of (str, str), default ('_x', '_y')
Suffix to apply to overlapping column names in the left and right
side, respectively. To raise an exception on overlapping columns use
(False, False).
copy : bool, default True
If False, avoid copy if possible.
indicator : bool or str, default False
If True, adds a column to output DataFrame called "_merge" with
information on the source of each row.
If string, column with information on source of each row will be added to
output DataFrame, and column will be named value of string.
Information column is Categorical-type and takes on a value of "left_only"
for observations whose merge key only appears in 'left' DataFrame,
"right_only" for observations whose merge key only appears in 'right'
DataFrame, and "both" if the observation's merge key is found in both.
validate : str, optional
If specified, checks if merge is of specified type.
* "one_to_one" or "1:1": check if merge keys are unique in both
left and right datasets.
* "one_to_many" or "1:m": check if merge keys are unique in left
dataset.
* "many_to_one" or "m:1": check if merge keys are unique in right
dataset.
* "many_to_many" or "m:m": allowed, but does not result in checks.
.. versionadded:: 0.21.0
Returns
-------
DataFrame
A DataFrame of the two merged objects.
See Also
--------
merge_ordered : Merge with optional filling/interpolation.
merge_asof : Merge on nearest keys.
DataFrame.join : Similar method using indices.
Notes
-----
Support for specifying index levels as the `on`, `left_on`, and
`right_on` parameters was added in version 0.23.0
Support for merging named Series objects was added in version 0.24.0
Examples
--------
>>> df1 = pd.DataFrame({'lkey': ['foo', 'bar', 'baz', 'foo'],
... 'value': [1, 2, 3, 5]})
>>> df2 = pd.DataFrame({'rkey': ['foo', 'bar', 'baz', 'foo'],
... 'value': [5, 6, 7, 8]})
>>> df1
lkey value
0 foo 1
1 bar 2
2 baz 3
3 foo 5
>>> df2
rkey value
0 foo 5
1 bar 6
2 baz 7
3 foo 8
Merge df1 and df2 on the lkey and rkey columns. The value columns have
the default suffixes, _x and _y, appended.
>>> df1.merge(df2, left_on='lkey', right_on='rkey')
lkey value_x rkey value_y
0 foo 1 foo 5
1 foo 1 foo 8
2 foo 5 foo 5
3 foo 5 foo 8
4 bar 2 bar 6
5 baz 3 baz 7
Merge DataFrames df1 and df2 with specified left and right suffixes
appended to any overlapping columns.
>>> df1.merge(df2, left_on='lkey', right_on='rkey',
... suffixes=('_left', '_right'))
lkey value_left rkey value_right
0 foo 1 foo 5
1 foo 1 foo 8
2 foo 5 foo 5
3 foo 5 foo 8
4 bar 2 bar 6
5 baz 3 baz 7
Merge DataFrames df1 and df2, but raise an exception if the DataFrames have
any overlapping columns.
>>> df1.merge(df2, left_on='lkey', right_on='rkey', suffixes=(False, False))
Traceback (most recent call last):
...
ValueError: columns overlap but no suffix specified:
Index(['value'], dtype='object')
"""
# -----------------------------------------------------------------------
# DataFrame class
class DataFrame(NDFrame):
"""
Two-dimensional size-mutable, potentially heterogeneous tabular data
structure with labeled axes (rows and columns). Arithmetic operations
align on both row and column labels. Can be thought of as a dict-like
container for Series objects. The primary pandas data structure.
Parameters
----------
data : ndarray (structured or homogeneous), Iterable, dict, or DataFrame
Dict can contain Series, arrays, constants, or list-like objects
.. versionchanged :: 0.23.0
If data is a dict, column order follows insertion-order for
Python 3.6 and later.
.. versionchanged :: 0.25.0
If data is a list of dicts, column order follows insertion-order
Python 3.6 and later.
index : Index or array-like
Index to use for resulting frame. Will default to RangeIndex if
no indexing information part of input data and no index provided
columns : Index or array-like
Column labels to use for resulting frame. Will default to
RangeIndex (0, 1, 2, ..., n) if no column labels are provided
dtype : dtype, default None
Data type to force. Only a single dtype is allowed. If None, infer
copy : boolean, default False
Copy data from inputs. Only affects DataFrame / 2d ndarray input
See Also
--------
DataFrame.from_records : Constructor from tuples, also record arrays.
DataFrame.from_dict : From dicts of Series, arrays, or dicts.
DataFrame.from_items : From sequence of (key, value) pairs
read_csv, pandas.read_table, pandas.read_clipboard.
Examples
--------
Constructing DataFrame from a dictionary.
>>> d = {'col1': [1, 2], 'col2': [3, 4]}
>>> df = pd.DataFrame(data=d)
>>> df
col1 col2
0 1 3
1 2 4
Notice that the inferred dtype is int64.
>>> df.dtypes
col1 int64
col2 int64
dtype: object
To enforce a single dtype:
>>> df = pd.DataFrame(data=d, dtype=np.int8)
>>> df.dtypes
col1 int8
col2 int8
dtype: object
Constructing DataFrame from numpy ndarray:
>>> df2 = pd.DataFrame(np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]]),
... columns=['a', 'b', 'c'])
>>> df2
a b c
0 1 2 3
1 4 5 6
2 7 8 9
"""
@property
def _constructor(self):
return DataFrame
_constructor_sliced = Series # type: Type[Series]
_deprecations = NDFrame._deprecations | frozenset(
["from_items"]
) # type: FrozenSet[str]
_accessors = set() # type: Set[str]
@property
def _constructor_expanddim(self):
raise NotImplementedError("Not supported for DataFrames!")
# ----------------------------------------------------------------------
# Constructors
def __init__(self, data=None, index=None, columns=None, dtype=None, copy=False):
if data is None:
data = {}
if dtype is not None:
dtype = self._validate_dtype(dtype)
if isinstance(data, DataFrame):
data = data._data
if isinstance(data, BlockManager):
mgr = self._init_mgr(
data, axes=dict(index=index, columns=columns), dtype=dtype, copy=copy
)
elif isinstance(data, dict):
mgr = init_dict(data, index, columns, dtype=dtype)
elif isinstance(data, ma.MaskedArray):
import numpy.ma.mrecords as mrecords
# masked recarray
if isinstance(data, mrecords.MaskedRecords):
mgr = masked_rec_array_to_mgr(data, index, columns, dtype, copy)
# a masked array
else:
mask = ma.getmaskarray(data)
if mask.any():
data, fill_value = maybe_upcast(data, copy=True)
data.soften_mask() # set hardmask False if it was True
data[mask] = fill_value
else:
data = data.copy()
mgr = init_ndarray(data, index, columns, dtype=dtype, copy=copy)
elif isinstance(data, (np.ndarray, Series, Index)):
if data.dtype.names:
data_columns = list(data.dtype.names)
data = {k: data[k] for k in data_columns}
if columns is None:
columns = data_columns
mgr = init_dict(data, index, columns, dtype=dtype)
elif getattr(data, "name", None) is not None:
mgr = init_dict({data.name: data}, index, columns, dtype=dtype)
else:
mgr = init_ndarray(data, index, columns, dtype=dtype, copy=copy)
# For data is list-like, or Iterable (will consume into list)
elif isinstance(data, abc.Iterable) and not isinstance(data, (str, bytes)):
if not isinstance(data, abc.Sequence):
data = list(data)
if len(data) > 0:
if is_list_like(data[0]) and getattr(data[0], "ndim", 1) == 1:
if is_named_tuple(data[0]) and columns is None:
columns = data[0]._fields
arrays, columns = to_arrays(data, columns, dtype=dtype)
columns = ensure_index(columns)
# set the index
if index is None:
if isinstance(data[0], Series):
index = get_names_from_index(data)
elif isinstance(data[0], Categorical):
index = ibase.default_index(len(data[0]))
else:
index = ibase.default_index(len(data))
mgr = arrays_to_mgr(arrays, columns, index, columns, dtype=dtype)
else:
mgr = init_ndarray(data, index, columns, dtype=dtype, copy=copy)
else:
mgr = init_dict({}, index, columns, dtype=dtype)
else:
try:
arr = np.array(data, dtype=dtype, copy=copy)
except (ValueError, TypeError) as e:
exc = TypeError(
"DataFrame constructor called with "
"incompatible data and dtype: {e}".format(e=e)
)
raise_with_traceback(exc)
if arr.ndim == 0 and index is not None and columns is not None:
values = cast_scalar_to_array(
(len(index), len(columns)), data, dtype=dtype
)
mgr = init_ndarray(
values, index, columns, dtype=values.dtype, copy=False
)
else:
raise ValueError("DataFrame constructor not properly called!")
NDFrame.__init__(self, mgr, fastpath=True)
# ----------------------------------------------------------------------
@property
def axes(self):
"""
Return a list representing the axes of the DataFrame.
It has the row axis labels and column axis labels as the only members.
They are returned in that order.
Examples
--------
>>> df = pd.DataFrame({'col1': [1, 2], 'col2': [3, 4]})
>>> df.axes
[RangeIndex(start=0, stop=2, step=1), Index(['col1', 'col2'],
dtype='object')]
"""
return [self.index, self.columns]
@property
def shape(self):
"""
Return a tuple representing the dimensionality of the DataFrame.
See Also
--------
ndarray.shape
Examples
--------
>>> df = pd.DataFrame({'col1': [1, 2], 'col2': [3, 4]})
>>> df.shape
(2, 2)
>>> df = pd.DataFrame({'col1': [1, 2], 'col2': [3, 4],
... 'col3': [5, 6]})
>>> df.shape
(2, 3)
"""
return len(self.index), len(self.columns)
@property
def _is_homogeneous_type(self):
"""
Whether all the columns in a DataFrame have the same type.
Returns
-------
bool
Examples
--------
>>> DataFrame({"A": [1, 2], "B": [3, 4]})._is_homogeneous_type
True
>>> DataFrame({"A": [1, 2], "B": [3.0, 4.0]})._is_homogeneous_type
False
Items with the same type but different sizes are considered
different types.
>>> DataFrame({
... "A": np.array([1, 2], dtype=np.int32),
... "B": np.array([1, 2], dtype=np.int64)})._is_homogeneous_type
False
"""
if self._data.any_extension_types:
return len({block.dtype for block in self._data.blocks}) == 1
else:
return not self._data.is_mixed_type
# ----------------------------------------------------------------------
# Rendering Methods
def _repr_fits_vertical_(self):
"""
Check length against max_rows.
"""
max_rows = get_option("display.max_rows")
return len(self) <= max_rows
def _repr_fits_horizontal_(self, ignore_width=False):
"""
Check if full repr fits in horizontal boundaries imposed by the display
options width and max_columns.
In case off non-interactive session, no boundaries apply.
`ignore_width` is here so ipnb+HTML output can behave the way
users expect. display.max_columns remains in effect.
GH3541, GH3573
"""
width, height = console.get_console_size()
max_columns = get_option("display.max_columns")
nb_columns = len(self.columns)
# exceed max columns
if (max_columns and nb_columns > max_columns) or (
(not ignore_width) and width and nb_columns > (width // 2)
):
return False
# used by repr_html under IPython notebook or scripts ignore terminal
# dims
if ignore_width or not console.in_interactive_session():
return True
if get_option("display.width") is not None or console.in_ipython_frontend():
# check at least the column row for excessive width
max_rows = 1
else:
max_rows = get_option("display.max_rows")
# when auto-detecting, so width=None and not in ipython front end
# check whether repr fits horizontal by actually checking
# the width of the rendered repr
buf = StringIO()
# only care about the stuff we'll actually print out
# and to_string on entire frame may be expensive
d = self
if not (max_rows is None): # unlimited rows
# min of two, where one may be None
d = d.iloc[: min(max_rows, len(d))]
else:
return True
d.to_string(buf=buf)
value = buf.getvalue()
repr_width = max(len(l) for l in value.split("\n"))
return repr_width < width
def _info_repr(self):
"""
True if the repr should show the info view.
"""
info_repr_option = get_option("display.large_repr") == "info"
return info_repr_option and not (
self._repr_fits_horizontal_() and self._repr_fits_vertical_()
)
def __repr__(self):
"""
Return a string representation for a particular DataFrame.
"""
buf = StringIO("")
if self._info_repr():
self.info(buf=buf)
return buf.getvalue()
max_rows = get_option("display.max_rows")
min_rows = get_option("display.min_rows")
max_cols = get_option("display.max_columns")
show_dimensions = get_option("display.show_dimensions")
if get_option("display.expand_frame_repr"):
width, _ = console.get_console_size()
else:
width = None
self.to_string(
buf=buf,
max_rows=max_rows,
min_rows=min_rows,
max_cols=max_cols,
line_width=width,
show_dimensions=show_dimensions,
)
return buf.getvalue()
def _repr_html_(self):
"""
Return a html representation for a particular DataFrame.
Mainly for IPython notebook.
"""
if self._info_repr():
buf = StringIO("")
self.info(buf=buf)
# need to escape the <class>, should be the first line.
val = buf.getvalue().replace("<", r"<", 1)
val = val.replace(">", r">", 1)
return "<pre>" + val + "</pre>"
if get_option("display.notebook_repr_html"):
max_rows = get_option("display.max_rows")
max_cols = get_option("display.max_columns")
show_dimensions = get_option("display.show_dimensions")
return self.to_html(
max_rows=max_rows,
max_cols=max_cols,
show_dimensions=show_dimensions,
notebook=True,
)
else:
return None
@Substitution(
header="Write out the column names. If a list of strings "
"is given, it is assumed to be aliases for the "
"column names",
col_space_type="int",
col_space="The minimum width of each column",
)
@Substitution(shared_params=fmt.common_docstring, returns=fmt.return_docstring)
def to_string(
self,
buf=None,
columns=None,
col_space=None,
header=True,
index=True,
na_rep="NaN",
formatters=None,
float_format=None,
sparsify=None,
index_names=True,
justify=None,
max_rows=None,
min_rows=None,
max_cols=None,
show_dimensions=False,
decimal=".",
line_width=None,
):
"""
Render a DataFrame to a console-friendly tabular output.
%(shared_params)s
line_width : int, optional
Width to wrap a line in characters.
%(returns)s
See Also
--------
to_html : Convert DataFrame to HTML.
Examples
--------
>>> d = {'col1': [1, 2, 3], 'col2': [4, 5, 6]}
>>> df = pd.DataFrame(d)
>>> print(df.to_string())
col1 col2
0 1 4
1 2 5
2 3 6
"""
formatter = fmt.DataFrameFormatter(
self,
buf=buf,
columns=columns,
col_space=col_space,
na_rep=na_rep,
formatters=formatters,
float_format=float_format,
sparsify=sparsify,
justify=justify,
index_names=index_names,
header=header,
index=index,
min_rows=min_rows,
max_rows=max_rows,
max_cols=max_cols,
show_dimensions=show_dimensions,
decimal=decimal,
line_width=line_width,
)
formatter.to_string()
if buf is None:
result = formatter.buf.getvalue()
return result
# ----------------------------------------------------------------------
@property
def style(self):
"""
Property returning a Styler object containing methods for
building a styled HTML representation fo the DataFrame.
See Also
--------
io.formats.style.Styler
"""
from pandas.io.formats.style import Styler
return Styler(self)
_shared_docs[
"items"
] = r"""
Iterator over (column name, Series) pairs.
Iterates over the DataFrame columns, returning a tuple with
the column name and the content as a Series.
%s
label : object
The column names for the DataFrame being iterated over.
content : Series
The column entries belonging to each label, as a Series.
See Also
--------
DataFrame.iterrows : Iterate over DataFrame rows as
(index, Series) pairs.
DataFrame.itertuples : Iterate over DataFrame rows as namedtuples
of the values.
Examples
--------
>>> df = pd.DataFrame({'species': ['bear', 'bear', 'marsupial'],
... 'population': [1864, 22000, 80000]},
... index=['panda', 'polar', 'koala'])
>>> df
species population
panda bear 1864
polar bear 22000
koala marsupial 80000
>>> for label, content in df.items():
... print('label:', label)
... print('content:', content, sep='\n')
...
label: species
content:
panda bear
polar bear
koala marsupial
Name: species, dtype: object
label: population
content:
panda 1864
polar 22000
koala 80000
Name: population, dtype: int64
"""
@Appender(_shared_docs["items"] % "Yields\n ------")
def items(self):
if self.columns.is_unique and hasattr(self, "_item_cache"):
for k in self.columns:
yield k, self._get_item_cache(k)
else:
for i, k in enumerate(self.columns):
yield k, self._ixs(i, axis=1)
@Appender(_shared_docs["items"] % "Returns\n -------")
def iteritems(self):
return self.items()
def iterrows(self):
"""
Iterate over DataFrame rows as (index, Series) pairs.
Yields
------
index : label or tuple of label
The index of the row. A tuple for a `MultiIndex`.
data : Series
The data of the row as a Series.
it : generator
A generator that iterates over the rows of the frame.
See Also
--------
itertuples : Iterate over DataFrame rows as namedtuples of the values.
items : Iterate over (column name, Series) pairs.
Notes
-----
1. Because ``iterrows`` returns a Series for each row,
it does **not** preserve dtypes across the rows (dtypes are
preserved across columns for DataFrames). For example,
>>> df = pd.DataFrame([[1, 1.5]], columns=['int', 'float'])
>>> row = next(df.iterrows())[1]
>>> row
int 1.0
float 1.5
Name: 0, dtype: float64
>>> print(row['int'].dtype)
float64
>>> print(df['int'].dtype)
int64
To preserve dtypes while iterating over the rows, it is better
to use :meth:`itertuples` which returns namedtuples of the values
and which is generally faster than ``iterrows``.
2. You should **never modify** something you are iterating over.
This is not guaranteed to work in all cases. Depending on the
data types, the iterator returns a copy and not a view, and writing
to it will have no effect.
"""
columns = self.columns
klass = self._constructor_sliced
for k, v in zip(self.index, self.values):
s = klass(v, index=columns, name=k)
yield k, s
def itertuples(self, index=True, name="Pandas"):
"""
Iterate over DataFrame rows as namedtuples.
Parameters
----------
index : bool, default True
If True, return the index as the first element of the tuple.
name : str or None, default "Pandas"
The name of the returned namedtuples or None to return regular
tuples.
Returns
-------
iterator
An object to iterate over namedtuples for each row in the
DataFrame with the first field possibly being the index and
following fields being the column values.
See Also
--------
DataFrame.iterrows : Iterate over DataFrame rows as (index, Series)
pairs.
DataFrame.items : Iterate over (column name, Series) pairs.
Notes
-----
The column names will be renamed to positional names if they are
invalid Python identifiers, repeated, or start with an underscore.
With a large number of columns (>255), regular tuples are returned.
Examples
--------
>>> df = pd.DataFrame({'num_legs': [4, 2], 'num_wings': [0, 2]},
... index=['dog', 'hawk'])
>>> df
num_legs num_wings
dog 4 0
hawk 2 2
>>> for row in df.itertuples():
... print(row)
...
Pandas(Index='dog', num_legs=4, num_wings=0)
Pandas(Index='hawk', num_legs=2, num_wings=2)
By setting the `index` parameter to False we can remove the index
as the first element of the tuple:
>>> for row in df.itertuples(index=False):
... print(row)
...
Pandas(num_legs=4, num_wings=0)
Pandas(num_legs=2, num_wings=2)
With the `name` parameter set we set a custom name for the yielded
namedtuples:
>>> for row in df.itertuples(name='Animal'):
... print(row)
...
Animal(Index='dog', num_legs=4, num_wings=0)
Animal(Index='hawk', num_legs=2, num_wings=2)
"""
arrays = []
fields = list(self.columns)
if index:
arrays.append(self.index)
fields.insert(0, "Index")
# use integer indexing because of possible duplicate column names
arrays.extend(self.iloc[:, k] for k in range(len(self.columns)))
# Python 3 supports at most 255 arguments to constructor
if name is not None and len(self.columns) + index < 256:
itertuple = collections.namedtuple(name, fields, rename=True)
return map(itertuple._make, zip(*arrays))
# fallback to regular tuples
return zip(*arrays)
def __len__(self):
"""
Returns length of info axis, but here we use the index.
"""
return len(self.index)
def dot(self, other):
"""
Compute the matrix multiplication between the DataFrame and other.
This method computes the matrix product between the DataFrame and the
values of an other Series, DataFrame or a numpy array.
It can also be called using ``self @ other`` in Python >= 3.5.
Parameters
----------
other : Series, DataFrame or array-like
The other object to compute the matrix product with.
Returns
-------
Series or DataFrame
If other is a Series, return the matrix product between self and
other as a Serie. If other is a DataFrame or a numpy.array, return
the matrix product of self and other in a DataFrame of a np.array.
See Also
--------
Series.dot: Similar method for Series.
Notes
-----
The dimensions of DataFrame and other must be compatible in order to
compute the matrix multiplication. In addition, the column names of
DataFrame and the index of other must contain the same values, as they
will be aligned prior to the multiplication.
The dot method for Series computes the inner product, instead of the
matrix product here.
Examples
--------
Here we multiply a DataFrame with a Series.
>>> df = pd.DataFrame([[0, 1, -2, -1], [1, 1, 1, 1]])
>>> s = pd.Series([1, 1, 2, 1])
>>> df.dot(s)
0 -4
1 5
dtype: int64
Here we multiply a DataFrame with another DataFrame.
>>> other = pd.DataFrame([[0, 1], [1, 2], [-1, -1], [2, 0]])
>>> df.dot(other)
0 1
0 1 4
1 2 2
Note that the dot method give the same result as @
>>> df @ other
0 1
0 1 4
1 2 2
The dot method works also if other is an np.array.
>>> arr = np.array([[0, 1], [1, 2], [-1, -1], [2, 0]])
>>> df.dot(arr)
0 1
0 1 4
1 2 2
Note how shuffling of the objects does not change the result.
>>> s2 = s.reindex([1, 0, 2, 3])
>>> df.dot(s2)
0 -4
1 5
dtype: int64
"""
if isinstance(other, (Series, DataFrame)):
common = self.columns.union(other.index)
if len(common) > len(self.columns) or len(common) > len(other.index):
raise ValueError("matrices are not aligned")
left = self.reindex(columns=common, copy=False)
right = other.reindex(index=common, copy=False)
lvals = left.values
rvals = right.values
else:
left = self
lvals = self.values
rvals = np.asarray(other)
if lvals.shape[1] != rvals.shape[0]:
raise ValueError(
"Dot product shape mismatch, "
"{s} vs {r}".format(s=lvals.shape, r=rvals.shape)
)
if isinstance(other, DataFrame):
return self._constructor(
np.dot(lvals, rvals), index=left.index, columns=other.columns
)
elif isinstance(other, Series):
return Series(np.dot(lvals, rvals), index=left.index)
elif isinstance(rvals, (np.ndarray, Index)):
result = np.dot(lvals, rvals)
if result.ndim == 2:
return self._constructor(result, index=left.index)
else:
return Series(result, index=left.index)
else: # pragma: no cover
raise TypeError("unsupported type: {oth}".format(oth=type(other)))
def __matmul__(self, other):
"""
Matrix multiplication using binary `@` operator in Python>=3.5.
"""
return self.dot(other)
def __rmatmul__(self, other):
"""
Matrix multiplication using binary `@` operator in Python>=3.5.
"""
return self.T.dot(np.transpose(other)).T
# ----------------------------------------------------------------------
# IO methods (to / from other formats)
@classmethod
def from_dict(cls, data, orient="columns", dtype=None, columns=None):
"""
Construct DataFrame from dict of array-like or dicts.
Creates DataFrame object from dictionary by columns or by index
allowing dtype specification.
Parameters
----------
data : dict
Of the form {field : array-like} or {field : dict}.
orient : {'columns', 'index'}, default 'columns'
The "orientation" of the data. If the keys of the passed dict
should be the columns of the resulting DataFrame, pass 'columns'
(default). Otherwise if the keys should be rows, pass 'index'.
dtype : dtype, default None
Data type to force, otherwise infer.
columns : list, default None
Column labels to use when ``orient='index'``. Raises a ValueError
if used with ``orient='columns'``.
.. versionadded:: 0.23.0
Returns
-------
DataFrame
See Also
--------
DataFrame.from_records : DataFrame from ndarray (structured
dtype), list of tuples, dict, or DataFrame.
DataFrame : DataFrame object creation using constructor.
Examples
--------
By default the keys of the dict become the DataFrame columns:
>>> data = {'col_1': [3, 2, 1, 0], 'col_2': ['a', 'b', 'c', 'd']}
>>> pd.DataFrame.from_dict(data)
col_1 col_2
0 3 a
1 2 b
2 1 c
3 0 d
Specify ``orient='index'`` to create the DataFrame using dictionary
keys as rows:
>>> data = {'row_1': [3, 2, 1, 0], 'row_2': ['a', 'b', 'c', 'd']}
>>> pd.DataFrame.from_dict(data, orient='index')
0 1 2 3
row_1 3 2 1 0
row_2 a b c d
When using the 'index' orientation, the column names can be
specified manually:
>>> pd.DataFrame.from_dict(data, orient='index',
... columns=['A', 'B', 'C', 'D'])
A B C D
row_1 3 2 1 0
row_2 a b c d
"""
index = None
orient = orient.lower()
if orient == "index":
if len(data) > 0:
# TODO speed up Series case
if isinstance(list(data.values())[0], (Series, dict)):
data = _from_nested_dict(data)
else:
data, index = list(data.values()), list(data.keys())
elif orient == "columns":
if columns is not None:
raise ValueError(
"cannot use columns parameter with " "orient='columns'"
)
else: # pragma: no cover
raise ValueError("only recognize index or columns for orient")
return cls(data, index=index, columns=columns, dtype=dtype)
def to_numpy(self, dtype=None, copy=False):
"""
Convert the DataFrame to a NumPy array.
.. versionadded:: 0.24.0
By default, the dtype of the returned array will be the common NumPy
dtype of all types in the DataFrame. For example, if the dtypes are
``float16`` and ``float32``, the results dtype will be ``float32``.
This may require copying data and coercing values, which may be
expensive.
Parameters
----------
dtype : str or numpy.dtype, optional
The dtype to pass to :meth:`numpy.asarray`
copy : bool, default False
Whether to ensure that the returned value is a not a view on
another array. Note that ``copy=False`` does not *ensure* that
``to_numpy()`` is no-copy. Rather, ``copy=True`` ensure that
a copy is made, even if not strictly necessary.
Returns
-------
numpy.ndarray
See Also
--------
Series.to_numpy : Similar method for Series.
Examples
--------
>>> pd.DataFrame({"A": [1, 2], "B": [3, 4]}).to_numpy()
array([[1, 3],
[2, 4]])
With heterogenous data, the lowest common type will have to
be used.
>>> df = pd.DataFrame({"A": [1, 2], "B": [3.0, 4.5]})
>>> df.to_numpy()
array([[1. , 3. ],
[2. , 4.5]])
For a mix of numeric and non-numeric types, the output array will
have object dtype.
>>> df['C'] = pd.date_range('2000', periods=2)
>>> df.to_numpy()
array([[1, 3.0, Timestamp('2000-01-01 00:00:00')],
[2, 4.5, Timestamp('2000-01-02 00:00:00')]], dtype=object)
"""
result = np.array(self.values, dtype=dtype, copy=copy)
return result
def to_dict(self, orient="dict", into=dict):
"""
Convert the DataFrame to a dictionary.
The type of the key-value pairs can be customized with the parameters
(see below).
Parameters
----------
orient : str {'dict', 'list', 'series', 'split', 'records', 'index'}
Determines the type of the values of the dictionary.
- 'dict' (default) : dict like {column -> {index -> value}}
- 'list' : dict like {column -> [values]}
- 'series' : dict like {column -> Series(values)}
- 'split' : dict like
{'index' -> [index], 'columns' -> [columns], 'data' -> [values]}
- 'records' : list like
[{column -> value}, ... , {column -> value}]
- 'index' : dict like {index -> {column -> value}}
Abbreviations are allowed. `s` indicates `series` and `sp`
indicates `split`.
into : class, default dict
The collections.abc.Mapping subclass used for all Mappings
in the return value. Can be the actual class or an empty
instance of the mapping type you want. If you want a
collections.defaultdict, you must pass it initialized.
.. versionadded:: 0.21.0
Returns
-------
dict, list or collections.abc.Mapping
Return a collections.abc.Mapping object representing the DataFrame.
The resulting transformation depends on the `orient` parameter.
See Also
--------
DataFrame.from_dict: Create a DataFrame from a dictionary.
DataFrame.to_json: Convert a DataFrame to JSON format.
Examples
--------
>>> df = pd.DataFrame({'col1': [1, 2],
... 'col2': [0.5, 0.75]},
... index=['row1', 'row2'])
>>> df
col1 col2
row1 1 0.50
row2 2 0.75
>>> df.to_dict()
{'col1': {'row1': 1, 'row2': 2}, 'col2': {'row1': 0.5, 'row2': 0.75}}
You can specify the return orientation.
>>> df.to_dict('series')
{'col1': row1 1
row2 2
Name: col1, dtype: int64,
'col2': row1 0.50
row2 0.75
Name: col2, dtype: float64}
>>> df.to_dict('split')
{'index': ['row1', 'row2'], 'columns': ['col1', 'col2'],
'data': [[1, 0.5], [2, 0.75]]}
>>> df.to_dict('records')
[{'col1': 1, 'col2': 0.5}, {'col1': 2, 'col2': 0.75}]
>>> df.to_dict('index')
{'row1': {'col1': 1, 'col2': 0.5}, 'row2': {'col1': 2, 'col2': 0.75}}
You can also specify the mapping type.
>>> from collections import OrderedDict, defaultdict
>>> df.to_dict(into=OrderedDict)
OrderedDict([('col1', OrderedDict([('row1', 1), ('row2', 2)])),
('col2', OrderedDict([('row1', 0.5), ('row2', 0.75)]))])
If you want a `defaultdict`, you need to initialize it:
>>> dd = defaultdict(list)
>>> df.to_dict('records', into=dd)
[defaultdict(<class 'list'>, {'col1': 1, 'col2': 0.5}),
defaultdict(<class 'list'>, {'col1': 2, 'col2': 0.75})]
"""
if not self.columns.is_unique:
warnings.warn(
"DataFrame columns are not unique, some " "columns will be omitted.",
UserWarning,
stacklevel=2,
)
# GH16122
into_c = com.standardize_mapping(into)
if orient.lower().startswith("d"):
return into_c((k, v.to_dict(into)) for k, v in self.items())
elif orient.lower().startswith("l"):
return into_c((k, v.tolist()) for k, v in self.items())
elif orient.lower().startswith("sp"):
return into_c(
(
("index", self.index.tolist()),
("columns", self.columns.tolist()),
(
"data",
[
list(map(com.maybe_box_datetimelike, t))
for t in self.itertuples(index=False, name=None)
],
),
)
)
elif orient.lower().startswith("s"):
return into_c((k, com.maybe_box_datetimelike(v)) for k, v in self.items())
elif orient.lower().startswith("r"):
columns = self.columns.tolist()
rows = (
dict(zip(columns, row))
for row in self.itertuples(index=False, name=None)
)
return [
into_c((k, com.maybe_box_datetimelike(v)) for k, v in row.items())
for row in rows
]
elif orient.lower().startswith("i"):
if not self.index.is_unique:
raise ValueError("DataFrame index must be unique for orient='index'.")
return into_c(
(t[0], dict(zip(self.columns, t[1:])))
for t in self.itertuples(name=None)
)
else:
raise ValueError("orient '{o}' not understood".format(o=orient))
def to_gbq(
self,
destination_table,
project_id=None,
chunksize=None,
reauth=False,
if_exists="fail",
auth_local_webserver=False,
table_schema=None,
location=None,
progress_bar=True,
credentials=None,
verbose=None,
private_key=None,
):
"""
Write a DataFrame to a Google BigQuery table.
This function requires the `pandas-gbq package
<https://pandas-gbq.readthedocs.io>`__.
See the `How to authenticate with Google BigQuery
<https://pandas-gbq.readthedocs.io/en/latest/howto/authentication.html>`__
guide for authentication instructions.
Parameters
----------
destination_table : str
Name of table to be written, in the form ``dataset.tablename``.
project_id : str, optional
Google BigQuery Account project ID. Optional when available from
the environment.
chunksize : int, optional
Number of rows to be inserted in each chunk from the dataframe.
Set to ``None`` to load the whole dataframe at once.
reauth : bool, default False
Force Google BigQuery to re-authenticate the user. This is useful
if multiple accounts are used.
if_exists : str, default 'fail'
Behavior when the destination table exists. Value can be one of:
``'fail'``
If table exists, do nothing.
``'replace'``
If table exists, drop it, recreate it, and insert data.
``'append'``
If table exists, insert data. Create if does not exist.
auth_local_webserver : bool, default False
Use the `local webserver flow`_ instead of the `console flow`_
when getting user credentials.
.. _local webserver flow:
http://google-auth-oauthlib.readthedocs.io/en/latest/reference/google_auth_oauthlib.flow.html#google_auth_oauthlib.flow.InstalledAppFlow.run_local_server
.. _console flow:
http://google-auth-oauthlib.readthedocs.io/en/latest/reference/google_auth_oauthlib.flow.html#google_auth_oauthlib.flow.InstalledAppFlow.run_console
*New in version 0.2.0 of pandas-gbq*.
table_schema : list of dicts, optional
List of BigQuery table fields to which according DataFrame
columns conform to, e.g. ``[{'name': 'col1', 'type':
'STRING'},...]``. If schema is not provided, it will be
generated according to dtypes of DataFrame columns. See
BigQuery API documentation on available names of a field.
*New in version 0.3.1 of pandas-gbq*.
location : str, optional
Location where the load job should run. See the `BigQuery locations
documentation
<https://cloud.google.com/bigquery/docs/dataset-locations>`__ for a
list of available locations. The location must match that of the
target dataset.
*New in version 0.5.0 of pandas-gbq*.
progress_bar : bool, default True
Use the library `tqdm` to show the progress bar for the upload,
chunk by chunk.
*New in version 0.5.0 of pandas-gbq*.
credentials : google.auth.credentials.Credentials, optional
Credentials for accessing Google APIs. Use this parameter to
override default credentials, such as to use Compute Engine
:class:`google.auth.compute_engine.Credentials` or Service
Account :class:`google.oauth2.service_account.Credentials`
directly.
*New in version 0.8.0 of pandas-gbq*.
.. versionadded:: 0.24.0
verbose : bool, deprecated
Deprecated in pandas-gbq version 0.4.0. Use the `logging module
to adjust verbosity instead
<https://pandas-gbq.readthedocs.io/en/latest/intro.html#logging>`__.
private_key : str, deprecated
Deprecated in pandas-gbq version 0.8.0. Use the ``credentials``
parameter and
:func:`google.oauth2.service_account.Credentials.from_service_account_info`
or
:func:`google.oauth2.service_account.Credentials.from_service_account_file`
instead.
Service account private key in JSON format. Can be file path
or string contents. This is useful for remote server
authentication (eg. Jupyter/IPython notebook on remote host).
See Also
--------
pandas_gbq.to_gbq : This function in the pandas-gbq library.
read_gbq : Read a DataFrame from Google BigQuery.
"""
from pandas.io import gbq
gbq.to_gbq(
self,
destination_table,
project_id=project_id,
chunksize=chunksize,
reauth=reauth,
if_exists=if_exists,
auth_local_webserver=auth_local_webserver,
table_schema=table_schema,
location=location,
progress_bar=progress_bar,
credentials=credentials,
verbose=verbose,
private_key=private_key,
)
@classmethod
def from_records(
cls,
data,
index=None,
exclude=None,
columns=None,
coerce_float=False,
nrows=None,
):
"""
Convert structured or record ndarray to DataFrame.
Parameters
----------
data : ndarray (structured dtype), list of tuples, dict, or DataFrame
index : string, list of fields, array-like
Field of array to use as the index, alternately a specific set of
input labels to use
exclude : sequence, default None
Columns or fields to exclude
columns : sequence, default None
Column names to use. If the passed data do not have names
associated with them, this argument provides names for the
columns. Otherwise this argument indicates the order of the columns
in the result (any names not found in the data will become all-NA
columns)
coerce_float : boolean, default False
Attempt to convert values of non-string, non-numeric objects (like
decimal.Decimal) to floating point, useful for SQL result sets
nrows : int, default None
Number of rows to read if data is an iterator
Returns
-------
DataFrame
"""
# Make a copy of the input columns so we can modify it
if columns is not None:
columns = ensure_index(columns)
if is_iterator(data):
if nrows == 0:
return cls()
try:
first_row = next(data)
except StopIteration:
return cls(index=index, columns=columns)
dtype = None
if hasattr(first_row, "dtype") and first_row.dtype.names:
dtype = first_row.dtype
values = [first_row]
if nrows is None:
values += data
else:
values.extend(itertools.islice(data, nrows - 1))
if dtype is not None:
data = np.array(values, dtype=dtype)
else:
data = values
if isinstance(data, dict):
if columns is None:
columns = arr_columns = ensure_index(sorted(data))
arrays = [data[k] for k in columns]
else:
arrays = []
arr_columns = []
for k, v in data.items():
if k in columns:
arr_columns.append(k)
arrays.append(v)
arrays, arr_columns = reorder_arrays(arrays, arr_columns, columns)
elif isinstance(data, (np.ndarray, DataFrame)):
arrays, columns = to_arrays(data, columns)
if columns is not None:
columns = ensure_index(columns)
arr_columns = columns
else:
arrays, arr_columns = to_arrays(data, columns, coerce_float=coerce_float)
arr_columns = ensure_index(arr_columns)
if columns is not None:
columns = ensure_index(columns)
else:
columns = arr_columns
if exclude is None:
exclude = set()
else:
exclude = set(exclude)
result_index = None
if index is not None:
if isinstance(index, str) or not hasattr(index, "__iter__"):
i = columns.get_loc(index)
exclude.add(index)
if len(arrays) > 0:
result_index = Index(arrays[i], name=index)
else:
result_index = Index([], name=index)
else:
try:
index_data = [arrays[arr_columns.get_loc(field)] for field in index]
result_index = ensure_index_from_sequences(index_data, names=index)
exclude.update(index)
except Exception:
result_index = index
if any(exclude):
arr_exclude = [x for x in exclude if x in arr_columns]
to_remove = [arr_columns.get_loc(col) for col in arr_exclude]
arrays = [v for i, v in enumerate(arrays) if i not in to_remove]
arr_columns = arr_columns.drop(arr_exclude)
columns = columns.drop(exclude)
mgr = arrays_to_mgr(arrays, arr_columns, result_index, columns)
return cls(mgr)
def to_records(
self, index=True, convert_datetime64=None, column_dtypes=None, index_dtypes=None
):
"""
Convert DataFrame to a NumPy record array.
Index will be included as the first field of the record array if
requested.
Parameters
----------
index : bool, default True
Include index in resulting record array, stored in 'index'
field or using the index label, if set.
convert_datetime64 : bool, default None
.. deprecated:: 0.23.0
Whether to convert the index to datetime.datetime if it is a
DatetimeIndex.
column_dtypes : str, type, dict, default None
.. versionadded:: 0.24.0
If a string or type, the data type to store all columns. If
a dictionary, a mapping of column names and indices (zero-indexed)
to specific data types.
index_dtypes : str, type, dict, default None
.. versionadded:: 0.24.0
If a string or type, the data type to store all index levels. If
a dictionary, a mapping of index level names and indices
(zero-indexed) to specific data types.
This mapping is applied only if `index=True`.
Returns
-------
numpy.recarray
NumPy ndarray with the DataFrame labels as fields and each row
of the DataFrame as entries.
See Also
--------
DataFrame.from_records: Convert structured or record ndarray
to DataFrame.
numpy.recarray: An ndarray that allows field access using
attributes, analogous to typed columns in a
spreadsheet.
Examples
--------
>>> df = pd.DataFrame({'A': [1, 2], 'B': [0.5, 0.75]},
... index=['a', 'b'])
>>> df
A B
a 1 0.50
b 2 0.75
>>> df.to_records()
rec.array([('a', 1, 0.5 ), ('b', 2, 0.75)],
dtype=[('index', 'O'), ('A', '<i8'), ('B', '<f8')])
If the DataFrame index has no label then the recarray field name
is set to 'index'. If the index has a label then this is used as the
field name:
>>> df.index = df.index.rename("I")
>>> df.to_records()
rec.array([('a', 1, 0.5 ), ('b', 2, 0.75)],
dtype=[('I', 'O'), ('A', '<i8'), ('B', '<f8')])
The index can be excluded from the record array:
>>> df.to_records(index=False)
rec.array([(1, 0.5 ), (2, 0.75)],
dtype=[('A', '<i8'), ('B', '<f8')])
Data types can be specified for the columns:
>>> df.to_records(column_dtypes={"A": "int32"})
rec.array([('a', 1, 0.5 ), ('b', 2, 0.75)],
dtype=[('I', 'O'), ('A', '<i4'), ('B', '<f8')])
As well as for the index:
>>> df.to_records(index_dtypes="<S2")
rec.array([(b'a', 1, 0.5 ), (b'b', 2, 0.75)],
dtype=[('I', 'S2'), ('A', '<i8'), ('B', '<f8')])
>>> index_dtypes = "<S{}".format(df.index.str.len().max())
>>> df.to_records(index_dtypes=index_dtypes)
rec.array([(b'a', 1, 0.5 ), (b'b', 2, 0.75)],
dtype=[('I', 'S1'), ('A', '<i8'), ('B', '<f8')])
"""
if convert_datetime64 is not None:
warnings.warn(
"The 'convert_datetime64' parameter is "
"deprecated and will be removed in a future "
"version",
FutureWarning,
stacklevel=2,
)
if index:
if is_datetime64_any_dtype(self.index) and convert_datetime64:
ix_vals = [self.index.to_pydatetime()]
else:
if isinstance(self.index, MultiIndex):
# array of tuples to numpy cols. copy copy copy
ix_vals = list(map(np.array, zip(*self.index.values)))
else:
ix_vals = [self.index.values]
arrays = ix_vals + [self[c]._internal_get_values() for c in self.columns]
count = 0
index_names = list(self.index.names)
if isinstance(self.index, MultiIndex):
for i, n in enumerate(index_names):
if n is None:
index_names[i] = "level_%d" % count
count += 1
elif index_names[0] is None:
index_names = ["index"]
names = [str(name) for name in itertools.chain(index_names, self.columns)]
else:
arrays = [self[c]._internal_get_values() for c in self.columns]
names = [str(c) for c in self.columns]
index_names = []
index_len = len(index_names)
formats = []
for i, v in enumerate(arrays):
index = i
# When the names and arrays are collected, we
# first collect those in the DataFrame's index,
# followed by those in its columns.
#
# Thus, the total length of the array is:
# len(index_names) + len(DataFrame.columns).
#
# This check allows us to see whether we are
# handling a name / array in the index or column.
if index < index_len:
dtype_mapping = index_dtypes
name = index_names[index]
else:
index -= index_len
dtype_mapping = column_dtypes
name = self.columns[index]
# We have a dictionary, so we get the data type
# associated with the index or column (which can
# be denoted by its name in the DataFrame or its
# position in DataFrame's array of indices or
# columns, whichever is applicable.
if is_dict_like(dtype_mapping):
if name in dtype_mapping:
dtype_mapping = dtype_mapping[name]
elif index in dtype_mapping:
dtype_mapping = dtype_mapping[index]
else:
dtype_mapping = None
# If no mapping can be found, use the array's
# dtype attribute for formatting.
#
# A valid dtype must either be a type or
# string naming a type.
if dtype_mapping is None:
formats.append(v.dtype)
elif isinstance(dtype_mapping, (type, np.dtype, str)):
formats.append(dtype_mapping)
else:
element = "row" if i < index_len else "column"
msg = (
"Invalid dtype {dtype} specified for " "{element} {name}"
).format(dtype=dtype_mapping, element=element, name=name)
raise ValueError(msg)
return np.rec.fromarrays(arrays, dtype={"names": names, "formats": formats})
@classmethod
def from_items(cls, items, columns=None, orient="columns"):
"""
Construct a DataFrame from a list of tuples.
.. deprecated:: 0.23.0
`from_items` is deprecated and will be removed in a future version.
Use :meth:`DataFrame.from_dict(dict(items)) <DataFrame.from_dict>`
instead.
:meth:`DataFrame.from_dict(OrderedDict(items)) <DataFrame.from_dict>`
may be used to preserve the key order.
Convert (key, value) pairs to DataFrame. The keys will be the axis
index (usually the columns, but depends on the specified
orientation). The values should be arrays or Series.
Parameters
----------
items : sequence of (key, value) pairs
Values should be arrays or Series.
columns : sequence of column labels, optional
Must be passed if orient='index'.
orient : {'columns', 'index'}, default 'columns'
The "orientation" of the data. If the keys of the
input correspond to column labels, pass 'columns'
(default). Otherwise if the keys correspond to the index,
pass 'index'.
Returns
-------
DataFrame
"""
warnings.warn(
"from_items is deprecated. Please use "
"DataFrame.from_dict(dict(items), ...) instead. "
"DataFrame.from_dict(OrderedDict(items)) may be used to "
"preserve the key order.",
FutureWarning,
stacklevel=2,
)
keys, values = zip(*items)
if orient == "columns":
if columns is not None:
columns = ensure_index(columns)
idict = dict(items)
if len(idict) < len(items):
if not columns.equals(ensure_index(keys)):
raise ValueError(
"With non-unique item names, passed "
"columns must be identical"
)
arrays = values
else:
arrays = [idict[k] for k in columns if k in idict]
else:
columns = ensure_index(keys)
arrays = values
# GH 17312
# Provide more informative error msg when scalar values passed
try:
return cls._from_arrays(arrays, columns, None)
except ValueError:
if not is_nested_list_like(values):
raise ValueError(
"The value in each (key, value) pair "
"must be an array, Series, or dict"
)
elif orient == "index":
if columns is None:
raise TypeError("Must pass columns with orient='index'")
keys = ensure_index(keys)
# GH 17312
# Provide more informative error msg when scalar values passed
try:
arr = np.array(values, dtype=object).T
data = [lib.maybe_convert_objects(v) for v in arr]
return cls._from_arrays(data, columns, keys)
except TypeError:
if not is_nested_list_like(values):
raise ValueError(
"The value in each (key, value) pair "
"must be an array, Series, or dict"
)
else: # pragma: no cover
raise ValueError("'orient' must be either 'columns' or 'index'")
@classmethod
def _from_arrays(cls, arrays, columns, index, dtype=None):
mgr = arrays_to_mgr(arrays, columns, index, columns, dtype=dtype)
return cls(mgr)
def to_sparse(self, fill_value=None, kind="block"):
"""
Convert to SparseDataFrame.
.. deprecated:: 0.25.0
Implement the sparse version of the DataFrame meaning that any data
matching a specific value it's omitted in the representation.
The sparse DataFrame allows for a more efficient storage.
Parameters
----------
fill_value : float, default None
The specific value that should be omitted in the representation.
kind : {'block', 'integer'}, default 'block'
The kind of the SparseIndex tracking where data is not equal to
the fill value:
- 'block' tracks only the locations and sizes of blocks of data.
- 'integer' keeps an array with all the locations of the data.
In most cases 'block' is recommended, since it's more memory
efficient.
Returns
-------
SparseDataFrame
The sparse representation of the DataFrame.
See Also
--------
DataFrame.to_dense :
Converts the DataFrame back to the its dense form.
Examples
--------
>>> df = pd.DataFrame([(np.nan, np.nan),
... (1., np.nan),
... (np.nan, 1.)])
>>> df
0 1
0 NaN NaN
1 1.0 NaN
2 NaN 1.0
>>> type(df)
<class 'pandas.core.frame.DataFrame'>
>>> sdf = df.to_sparse() # doctest: +SKIP
>>> sdf # doctest: +SKIP
0 1
0 NaN NaN
1 1.0 NaN
2 NaN 1.0
>>> type(sdf) # doctest: +SKIP
<class 'pandas.core.sparse.frame.SparseDataFrame'>
"""
warnings.warn(
"DataFrame.to_sparse is deprecated and will be removed "
"in a future version",
FutureWarning,
stacklevel=2,
)
from pandas.core.sparse.api import SparseDataFrame
with warnings.catch_warnings():
warnings.filterwarnings("ignore", message="SparseDataFrame")
return SparseDataFrame(
self._series,
index=self.index,
columns=self.columns,
default_kind=kind,
default_fill_value=fill_value,
)
@deprecate_kwarg(old_arg_name="encoding", new_arg_name=None)
def to_stata(
self,
fname,
convert_dates=None,
write_index=True,
encoding="latin-1",
byteorder=None,
time_stamp=None,
data_label=None,
variable_labels=None,
version=114,
convert_strl=None,
):
"""
Export DataFrame object to Stata dta format.
Writes the DataFrame to a Stata dataset file.
"dta" files contain a Stata dataset.
Parameters
----------
fname : str, buffer or path object
String, path object (pathlib.Path or py._path.local.LocalPath) or
object implementing a binary write() function. If using a buffer
then the buffer will not be automatically closed after the file
data has been written.
convert_dates : dict
Dictionary mapping columns containing datetime types to stata
internal format to use when writing the dates. Options are 'tc',
'td', 'tm', 'tw', 'th', 'tq', 'ty'. Column can be either an integer
or a name. Datetime columns that do not have a conversion type
specified will be converted to 'tc'. Raises NotImplementedError if
a datetime column has timezone information.
write_index : bool
Write the index to Stata dataset.
encoding : str
Default is latin-1. Unicode is not supported.
byteorder : str
Can be ">", "<", "little", or "big". default is `sys.byteorder`.
time_stamp : datetime
A datetime to use as file creation date. Default is the current
time.
data_label : str, optional
A label for the data set. Must be 80 characters or smaller.
variable_labels : dict
Dictionary containing columns as keys and variable labels as
values. Each label must be 80 characters or smaller.
version : {114, 117}, default 114
Version to use in the output dta file. Version 114 can be used
read by Stata 10 and later. Version 117 can be read by Stata 13
or later. Version 114 limits string variables to 244 characters or
fewer while 117 allows strings with lengths up to 2,000,000
characters.
.. versionadded:: 0.23.0
convert_strl : list, optional
List of column names to convert to string columns to Stata StrL
format. Only available if version is 117. Storing strings in the
StrL format can produce smaller dta files if strings have more than
8 characters and values are repeated.
.. versionadded:: 0.23.0
Raises
------
NotImplementedError
* If datetimes contain timezone information
* Column dtype is not representable in Stata
ValueError
* Columns listed in convert_dates are neither datetime64[ns]
or datetime.datetime
* Column listed in convert_dates is not in DataFrame
* Categorical label contains more than 32,000 characters
See Also
--------
read_stata : Import Stata data files.
io.stata.StataWriter : Low-level writer for Stata data files.
io.stata.StataWriter117 : Low-level writer for version 117 files.
Examples
--------
>>> df = pd.DataFrame({'animal': ['falcon', 'parrot', 'falcon',
... 'parrot'],
... 'speed': [350, 18, 361, 15]})
>>> df.to_stata('animals.dta') # doctest: +SKIP
"""
kwargs = {}
if version not in (114, 117):
raise ValueError("Only formats 114 and 117 supported.")
if version == 114:
if convert_strl is not None:
raise ValueError(
"strl support is only available when using " "format 117"
)
from pandas.io.stata import StataWriter as statawriter
else:
from pandas.io.stata import StataWriter117 as statawriter
kwargs["convert_strl"] = convert_strl
writer = statawriter(
fname,
self,
convert_dates=convert_dates,
byteorder=byteorder,
time_stamp=time_stamp,
data_label=data_label,
write_index=write_index,
variable_labels=variable_labels,
**kwargs
)
writer.write_file()
def to_feather(self, fname):
"""
Write out the binary feather-format for DataFrames.
.. versionadded:: 0.20.0
Parameters
----------
fname : str
string file path
"""
from pandas.io.feather_format import to_feather
to_feather(self, fname)
def to_parquet(
self,
fname,
engine="auto",
compression="snappy",
index=None,
partition_cols=None,
**kwargs
):
"""
Write a DataFrame to the binary parquet format.
.. versionadded:: 0.21.0
This function writes the dataframe as a `parquet file
<https://parquet.apache.org/>`_. You can choose different parquet
backends, and have the option of compression. See
:ref:`the user guide <io.parquet>` for more details.
Parameters
----------
fname : str
File path or Root Directory path. Will be used as Root Directory
path while writing a partitioned dataset.
.. versionchanged:: 0.24.0
engine : {'auto', 'pyarrow', 'fastparquet'}, default 'auto'
Parquet library to use. If 'auto', then the option
``io.parquet.engine`` is used. The default ``io.parquet.engine``
behavior is to try 'pyarrow', falling back to 'fastparquet' if
'pyarrow' is unavailable.
compression : {'snappy', 'gzip', 'brotli', None}, default 'snappy'
Name of the compression to use. Use ``None`` for no compression.
index : bool, default None
If ``True``, include the dataframe's index(es) in the file output.
If ``False``, they will not be written to the file. If ``None``,
the behavior depends on the chosen engine.
.. versionadded:: 0.24.0
partition_cols : list, optional, default None
Column names by which to partition the dataset
Columns are partitioned in the order they are given
.. versionadded:: 0.24.0
**kwargs
Additional arguments passed to the parquet library. See
:ref:`pandas io <io.parquet>` for more details.
See Also
--------
read_parquet : Read a parquet file.
DataFrame.to_csv : Write a csv file.
DataFrame.to_sql : Write to a sql table.
DataFrame.to_hdf : Write to hdf.
Notes
-----
This function requires either the `fastparquet
<https://pypi.org/project/fastparquet>`_ or `pyarrow
<https://arrow.apache.org/docs/python/>`_ library.
Examples
--------
>>> df = pd.DataFrame(data={'col1': [1, 2], 'col2': [3, 4]})
>>> df.to_parquet('df.parquet.gzip',
... compression='gzip') # doctest: +SKIP
>>> pd.read_parquet('df.parquet.gzip') # doctest: +SKIP
col1 col2
0 1 3
1 2 4
"""
from pandas.io.parquet import to_parquet
to_parquet(
self,
fname,
engine,
compression=compression,
index=index,
partition_cols=partition_cols,
**kwargs
)
@Substitution(
header="Whether to print column labels, default True",
col_space_type="str or int",
col_space="The minimum width of each column in CSS length "
"units. An int is assumed to be px units.\n\n"
" .. versionadded:: 0.25.0\n"
" Ability to use str",
)
@Substitution(shared_params=fmt.common_docstring, returns=fmt.return_docstring)
def to_html(
self,
buf=None,
columns=None,
col_space=None,
header=True,
index=True,
na_rep="NaN",
formatters=None,
float_format=None,
sparsify=None,
index_names=True,
justify=None,
max_rows=None,
max_cols=None,
show_dimensions=False,
decimal=".",
bold_rows=True,
classes=None,
escape=True,
notebook=False,
border=None,
table_id=None,
render_links=False,
):
"""
Render a DataFrame as an HTML table.
%(shared_params)s
bold_rows : bool, default True
Make the row labels bold in the output.
classes : str or list or tuple, default None
CSS class(es) to apply to the resulting html table.
escape : bool, default True
Convert the characters <, >, and & to HTML-safe sequences.
notebook : {True, False}, default False
Whether the generated HTML is for IPython Notebook.
border : int
A ``border=border`` attribute is included in the opening
`<table>` tag. Default ``pd.options.display.html.border``.
table_id : str, optional
A css id is included in the opening `<table>` tag if specified.
.. versionadded:: 0.23.0
render_links : bool, default False
Convert URLs to HTML links.
.. versionadded:: 0.24.0
%(returns)s
See Also
--------
to_string : Convert DataFrame to a string.
"""
if justify is not None and justify not in fmt._VALID_JUSTIFY_PARAMETERS:
raise ValueError("Invalid value for justify parameter")
formatter = fmt.DataFrameFormatter(
self,
buf=buf,
columns=columns,
col_space=col_space,
na_rep=na_rep,
formatters=formatters,
float_format=float_format,
sparsify=sparsify,
justify=justify,
index_names=index_names,
header=header,
index=index,
bold_rows=bold_rows,
escape=escape,
max_rows=max_rows,
max_cols=max_cols,
show_dimensions=show_dimensions,
decimal=decimal,
table_id=table_id,
render_links=render_links,
)
# TODO: a generic formatter wld b in DataFrameFormatter
formatter.to_html(classes=classes, notebook=notebook, border=border)
if buf is None:
return formatter.buf.getvalue()
# ----------------------------------------------------------------------
def info(
self, verbose=None, buf=None, max_cols=None, memory_usage=None, null_counts=None
):
"""
Print a concise summary of a DataFrame.
This method prints information about a DataFrame including
the index dtype and column dtypes, non-null values and memory usage.
Parameters
----------
verbose : bool, optional
Whether to print the full summary. By default, the setting in
``pandas.options.display.max_info_columns`` is followed.
buf : writable buffer, defaults to sys.stdout
Where to send the output. By default, the output is printed to
sys.stdout. Pass a writable buffer if you need to further process
the output.
max_cols : int, optional
When to switch from the verbose to the truncated output. If the
DataFrame has more than `max_cols` columns, the truncated output
is used. By default, the setting in
``pandas.options.display.max_info_columns`` is used.
memory_usage : bool, str, optional
Specifies whether total memory usage of the DataFrame
elements (including the index) should be displayed. By default,
this follows the ``pandas.options.display.memory_usage`` setting.
True always show memory usage. False never shows memory usage.
A value of 'deep' is equivalent to "True with deep introspection".
Memory usage is shown in human-readable units (base-2
representation). Without deep introspection a memory estimation is
made based in column dtype and number of rows assuming values
consume the same memory amount for corresponding dtypes. With deep
memory introspection, a real memory usage calculation is performed
at the cost of computational resources.
null_counts : bool, optional
Whether to show the non-null counts. By default, this is shown
only if the frame is smaller than
``pandas.options.display.max_info_rows`` and
``pandas.options.display.max_info_columns``. A value of True always
shows the counts, and False never shows the counts.
Returns
-------
None
This method prints a summary of a DataFrame and returns None.
See Also
--------
DataFrame.describe: Generate descriptive statistics of DataFrame
columns.
DataFrame.memory_usage: Memory usage of DataFrame columns.
Examples
--------
>>> int_values = [1, 2, 3, 4, 5]
>>> text_values = ['alpha', 'beta', 'gamma', 'delta', 'epsilon']
>>> float_values = [0.0, 0.25, 0.5, 0.75, 1.0]
>>> df = pd.DataFrame({"int_col": int_values, "text_col": text_values,
... "float_col": float_values})
>>> df
int_col text_col float_col
0 1 alpha 0.00
1 2 beta 0.25
2 3 gamma 0.50
3 4 delta 0.75
4 5 epsilon 1.00
Prints information of all columns:
>>> df.info(verbose=True)
<class 'pandas.core.frame.DataFrame'>
RangeIndex: 5 entries, 0 to 4
Data columns (total 3 columns):
int_col 5 non-null int64
text_col 5 non-null object
float_col 5 non-null float64
dtypes: float64(1), int64(1), object(1)
memory usage: 248.0+ bytes
Prints a summary of columns count and its dtypes but not per column
information:
>>> df.info(verbose=False)
<class 'pandas.core.frame.DataFrame'>
RangeIndex: 5 entries, 0 to 4
Columns: 3 entries, int_col to float_col
dtypes: float64(1), int64(1), object(1)
memory usage: 248.0+ bytes
Pipe output of DataFrame.info to buffer instead of sys.stdout, get
buffer content and writes to a text file:
>>> import io
>>> buffer = io.StringIO()
>>> df.info(buf=buffer)
>>> s = buffer.getvalue()
>>> with open("df_info.txt", "w",
... encoding="utf-8") as f: # doctest: +SKIP
... f.write(s)
260
The `memory_usage` parameter allows deep introspection mode, specially
useful for big DataFrames and fine-tune memory optimization:
>>> random_strings_array = np.random.choice(['a', 'b', 'c'], 10 ** 6)
>>> df = pd.DataFrame({
... 'column_1': np.random.choice(['a', 'b', 'c'], 10 ** 6),
... 'column_2': np.random.choice(['a', 'b', 'c'], 10 ** 6),
... 'column_3': np.random.choice(['a', 'b', 'c'], 10 ** 6)
... })
>>> df.info()
<class 'pandas.core.frame.DataFrame'>
RangeIndex: 1000000 entries, 0 to 999999
Data columns (total 3 columns):
column_1 1000000 non-null object
column_2 1000000 non-null object
column_3 1000000 non-null object
dtypes: object(3)
memory usage: 22.9+ MB
>>> df.info(memory_usage='deep')
<class 'pandas.core.frame.DataFrame'>
RangeIndex: 1000000 entries, 0 to 999999
Data columns (total 3 columns):
column_1 1000000 non-null object
column_2 1000000 non-null object
column_3 1000000 non-null object
dtypes: object(3)
memory usage: 188.8 MB
"""
if buf is None: # pragma: no cover
buf = sys.stdout
lines = []
lines.append(str(type(self)))
lines.append(self.index._summary())
if len(self.columns) == 0:
lines.append("Empty {name}".format(name=type(self).__name__))
fmt.buffer_put_lines(buf, lines)
return
cols = self.columns
# hack
if max_cols is None:
max_cols = get_option("display.max_info_columns", len(self.columns) + 1)
max_rows = get_option("display.max_info_rows", len(self) + 1)
if null_counts is None:
show_counts = (len(self.columns) <= max_cols) and (len(self) < max_rows)
else:
show_counts = null_counts
exceeds_info_cols = len(self.columns) > max_cols
def _verbose_repr():
lines.append("Data columns (total %d columns):" % len(self.columns))
space = max(len(pprint_thing(k)) for k in self.columns) + 4
counts = None
tmpl = "{count}{dtype}"
if show_counts:
counts = self.count()
if len(cols) != len(counts): # pragma: no cover
raise AssertionError(
"Columns must equal counts "
"({cols:d} != {counts:d})".format(
cols=len(cols), counts=len(counts)
)
)
tmpl = "{count} non-null {dtype}"
dtypes = self.dtypes
for i, col in enumerate(self.columns):
dtype = dtypes.iloc[i]
col = pprint_thing(col)
count = ""
if show_counts:
count = counts.iloc[i]
lines.append(
_put_str(col, space) + tmpl.format(count=count, dtype=dtype)
)
def _non_verbose_repr():
lines.append(self.columns._summary(name="Columns"))
def _sizeof_fmt(num, size_qualifier):
# returns size in human readable format
for x in ["bytes", "KB", "MB", "GB", "TB"]:
if num < 1024.0:
return "{num:3.1f}{size_q} " "{x}".format(
num=num, size_q=size_qualifier, x=x
)
num /= 1024.0
return "{num:3.1f}{size_q} {pb}".format(
num=num, size_q=size_qualifier, pb="PB"
)
if verbose:
_verbose_repr()
elif verbose is False: # specifically set to False, not nesc None
_non_verbose_repr()
else:
if exceeds_info_cols:
_non_verbose_repr()
else:
_verbose_repr()
counts = self._data.get_dtype_counts()
dtypes = ["{k}({kk:d})".format(k=k[0], kk=k[1]) for k in sorted(counts.items())]
lines.append("dtypes: {types}".format(types=", ".join(dtypes)))
if memory_usage is None:
memory_usage = get_option("display.memory_usage")
if memory_usage:
# append memory usage of df to display
size_qualifier = ""
if memory_usage == "deep":
deep = True
else:
# size_qualifier is just a best effort; not guaranteed to catch
# all cases (e.g., it misses categorical data even with object
# categories)
deep = False
if "object" in counts or self.index._is_memory_usage_qualified():
size_qualifier = "+"
mem_usage = self.memory_usage(index=True, deep=deep).sum()
lines.append(
"memory usage: {mem}\n".format(
mem=_sizeof_fmt(mem_usage, size_qualifier)
)
)
fmt.buffer_put_lines(buf, lines)
def memory_usage(self, index=True, deep=False):
"""
Return the memory usage of each column in bytes.
The memory usage can optionally include the contribution of
the index and elements of `object` dtype.
This value is displayed in `DataFrame.info` by default. This can be
suppressed by setting ``pandas.options.display.memory_usage`` to False.
Parameters
----------
index : bool, default True
Specifies whether to include the memory usage of the DataFrame's
index in returned Series. If ``index=True``, the memory usage of
the index is the first item in the output.
deep : bool, default False
If True, introspect the data deeply by interrogating
`object` dtypes for system-level memory consumption, and include
it in the returned values.
Returns
-------
Series
A Series whose index is the original column names and whose values
is the memory usage of each column in bytes.
See Also
--------
numpy.ndarray.nbytes : Total bytes consumed by the elements of an
ndarray.
Series.memory_usage : Bytes consumed by a Series.
Categorical : Memory-efficient array for string values with
many repeated values.
DataFrame.info : Concise summary of a DataFrame.
Examples
--------
>>> dtypes = ['int64', 'float64', 'complex128', 'object', 'bool']
>>> data = dict([(t, np.ones(shape=5000).astype(t))
... for t in dtypes])
>>> df = pd.DataFrame(data)
>>> df.head()
int64 float64 complex128 object bool
0 1 1.0 1.0+0.0j 1 True
1 1 1.0 1.0+0.0j 1 True
2 1 1.0 1.0+0.0j 1 True
3 1 1.0 1.0+0.0j 1 True
4 1 1.0 1.0+0.0j 1 True
>>> df.memory_usage()
Index 128
int64 40000
float64 40000
complex128 80000
object 40000
bool 5000
dtype: int64
>>> df.memory_usage(index=False)
int64 40000
float64 40000
complex128 80000
object 40000
bool 5000
dtype: int64
The memory footprint of `object` dtype columns is ignored by default:
>>> df.memory_usage(deep=True)
Index 128
int64 40000
float64 40000
complex128 80000
object 160000
bool 5000
dtype: int64
Use a Categorical for efficient storage of an object-dtype column with
many repeated values.
>>> df['object'].astype('category').memory_usage(deep=True)
5216
"""
result = Series(
[c.memory_usage(index=False, deep=deep) for col, c in self.items()],
index=self.columns,
)
if index:
result = Series(self.index.memory_usage(deep=deep), index=["Index"]).append(
result
)
return result
def transpose(self, *args, **kwargs):
"""
Transpose index and columns.
Reflect the DataFrame over its main diagonal by writing rows as columns
and vice-versa. The property :attr:`.T` is an accessor to the method
:meth:`transpose`.
Parameters
----------
copy : bool, default False
If True, the underlying data is copied. Otherwise (default), no
copy is made if possible.
*args, **kwargs
Additional keywords have no effect but might be accepted for
compatibility with numpy.
Returns
-------
DataFrame
The transposed DataFrame.
See Also
--------
numpy.transpose : Permute the dimensions of a given array.
Notes
-----
Transposing a DataFrame with mixed dtypes will result in a homogeneous
DataFrame with the `object` dtype. In such a case, a copy of the data
is always made.
Examples
--------
**Square DataFrame with homogeneous dtype**
>>> d1 = {'col1': [1, 2], 'col2': [3, 4]}
>>> df1 = pd.DataFrame(data=d1)
>>> df1
col1 col2
0 1 3
1 2 4
>>> df1_transposed = df1.T # or df1.transpose()
>>> df1_transposed
0 1
col1 1 2
col2 3 4
When the dtype is homogeneous in the original DataFrame, we get a
transposed DataFrame with the same dtype:
>>> df1.dtypes
col1 int64
col2 int64
dtype: object
>>> df1_transposed.dtypes
0 int64
1 int64
dtype: object
**Non-square DataFrame with mixed dtypes**
>>> d2 = {'name': ['Alice', 'Bob'],
... 'score': [9.5, 8],
... 'employed': [False, True],
... 'kids': [0, 0]}
>>> df2 = pd.DataFrame(data=d2)
>>> df2
name score employed kids
0 Alice 9.5 False 0
1 Bob 8.0 True 0
>>> df2_transposed = df2.T # or df2.transpose()
>>> df2_transposed
0 1
name Alice Bob
score 9.5 8
employed False True
kids 0 0
When the DataFrame has mixed dtypes, we get a transposed DataFrame with
the `object` dtype:
>>> df2.dtypes
name object
score float64
employed bool
kids int64
dtype: object
>>> df2_transposed.dtypes
0 object
1 object
dtype: object
"""
nv.validate_transpose(args, dict())
return super().transpose(1, 0, **kwargs)
T = property(transpose)
# ----------------------------------------------------------------------
# Picklability
# legacy pickle formats
def _unpickle_frame_compat(self, state): # pragma: no cover
if len(state) == 2: # pragma: no cover
series, idx = state
columns = sorted(series)
else:
series, cols, idx = state
columns = com._unpickle_array(cols)
index = com._unpickle_array(idx)
self._data = self._init_dict(series, index, columns, None)
def _unpickle_matrix_compat(self, state): # pragma: no cover
# old unpickling
(vals, idx, cols), object_state = state
index = com._unpickle_array(idx)
dm = DataFrame(vals, index=index, columns=com._unpickle_array(cols), copy=False)
if object_state is not None:
ovals, _, ocols = object_state
objects = DataFrame(
ovals, index=index, columns=com._unpickle_array(ocols), copy=False
)
dm = dm.join(objects)
self._data = dm._data
# ----------------------------------------------------------------------
# Getting and setting elements
def _get_value(self, index, col, takeable: bool = False):
"""
Quickly retrieve single value at passed column and index.
Parameters
----------
index : row label
col : column label
takeable : interpret the index/col as indexers, default False
Returns
-------
scalar
"""
if takeable:
series = self._iget_item_cache(col)
return com.maybe_box_datetimelike(series._values[index])
series = self._get_item_cache(col)
engine = self.index._engine
try:
return engine.get_value(series._values, index)
except KeyError:
# GH 20629
if self.index.nlevels > 1:
# partial indexing forbidden
raise
except (TypeError, ValueError):
pass
# we cannot handle direct indexing
# use positional
col = self.columns.get_loc(col)
index = self.index.get_loc(index)
return self._get_value(index, col, takeable=True)
def _set_value(self, index, col, value, takeable: bool = False):
"""
Put single value at passed column and index.
Parameters
----------
index : row label
col : column label
value : scalar
takeable : interpret the index/col as indexers, default False
Returns
-------
DataFrame
If label pair is contained, will be reference to calling DataFrame,
otherwise a new object.
"""
try:
if takeable is True:
series = self._iget_item_cache(col)
return series._set_value(index, value, takeable=True)
series = self._get_item_cache(col)
engine = self.index._engine
engine.set_value(series._values, index, value)
return self
except (KeyError, TypeError):
# set using a non-recursive method & reset the cache
if takeable:
self.iloc[index, col] = value
else:
self.loc[index, col] = value
self._item_cache.pop(col, None)
return self
def _ixs(self, i: int, axis: int = 0):
"""
Parameters
----------
i : int
axis : int
Notes
-----
If slice passed, the resulting data will be a view.
"""
# irow
if axis == 0:
label = self.index[i]
new_values = self._data.fast_xs(i)
if is_scalar(new_values):
return new_values
# if we are a copy, mark as such
copy = isinstance(new_values, np.ndarray) and new_values.base is None
result = self._constructor_sliced(
new_values,
index=self.columns,
name=self.index[i],
dtype=new_values.dtype,
)
result._set_is_copy(self, copy=copy)
return result
# icol
else:
label = self.columns[i]
# if the values returned are not the same length
# as the index (iow a not found value), iget returns
# a 0-len ndarray. This is effectively catching
# a numpy error (as numpy should really raise)
values = self._data.iget(i)
if len(self.index) and not len(values):
values = np.array([np.nan] * len(self.index), dtype=object)
result = self._box_col_values(values, label)
# this is a cached value, mark it so
result._set_as_cached(label, self)
return result
def __getitem__(self, key):
key = lib.item_from_zerodim(key)
key = com.apply_if_callable(key, self)
if is_hashable(key):
# shortcut if the key is in columns
if self.columns.is_unique and key in self.columns:
if self.columns.nlevels > 1:
return self._getitem_multilevel(key)
return self._get_item_cache(key)
# Do we have a slicer (on rows)?
indexer = convert_to_index_sliceable(self, key)
if indexer is not None:
return self._slice(indexer, axis=0)
# Do we have a (boolean) DataFrame?
if isinstance(key, DataFrame):
return self._getitem_frame(key)
# Do we have a (boolean) 1d indexer?
if com.is_bool_indexer(key):
return self._getitem_bool_array(key)
# We are left with two options: a single key, and a collection of keys,
# We interpret tuples as collections only for non-MultiIndex
is_single_key = isinstance(key, tuple) or not is_list_like(key)
if is_single_key:
if self.columns.nlevels > 1:
return self._getitem_multilevel(key)
indexer = self.columns.get_loc(key)
if is_integer(indexer):
indexer = [indexer]
else:
if is_iterator(key):
key = list(key)
indexer = self.loc._get_listlike_indexer(key, axis=1, raise_missing=True)[1]
# take() does not accept boolean indexers
if getattr(indexer, "dtype", None) == bool:
indexer = np.where(indexer)[0]
data = self.take(indexer, axis=1)
if is_single_key:
# What does looking for a single key in a non-unique index return?
# The behavior is inconsistent. It returns a Series, except when
# - the key itself is repeated (test on data.shape, #9519), or
# - we have a MultiIndex on columns (test on self.columns, #21309)
if data.shape[1] == 1 and not isinstance(self.columns, MultiIndex):
data = data[key]
return data
def _getitem_bool_array(self, key):
# also raises Exception if object array with NA values
# warning here just in case -- previously __setitem__ was
# reindexing but __getitem__ was not; it seems more reasonable to
# go with the __setitem__ behavior since that is more consistent
# with all other indexing behavior
if isinstance(key, Series) and not key.index.equals(self.index):
warnings.warn(
"Boolean Series key will be reindexed to match " "DataFrame index.",
UserWarning,
stacklevel=3,
)
elif len(key) != len(self.index):
raise ValueError(
"Item wrong length %d instead of %d." % (len(key), len(self.index))
)
# check_bool_indexer will throw exception if Series key cannot
# be reindexed to match DataFrame rows
key = check_bool_indexer(self.index, key)
indexer = key.nonzero()[0]
return self.take(indexer, axis=0)
def _getitem_multilevel(self, key):
loc = self.columns.get_loc(key)
if isinstance(loc, (slice, Series, np.ndarray, Index)):
new_columns = self.columns[loc]
result_columns = maybe_droplevels(new_columns, key)
if self._is_mixed_type:
result = self.reindex(columns=new_columns)
result.columns = result_columns
else:
new_values = self.values[:, loc]
result = self._constructor(
new_values, index=self.index, columns=result_columns
)
result = result.__finalize__(self)
# If there is only one column being returned, and its name is
# either an empty string, or a tuple with an empty string as its
# first element, then treat the empty string as a placeholder
# and return the column as if the user had provided that empty
# string in the key. If the result is a Series, exclude the
# implied empty string from its name.
if len(result.columns) == 1:
top = result.columns[0]
if isinstance(top, tuple):
top = top[0]
if top == "":
result = result[""]
if isinstance(result, Series):
result = self._constructor_sliced(
result, index=self.index, name=key
)
result._set_is_copy(self)
return result
else:
return self._get_item_cache(key)
def _getitem_frame(self, key):
if key.values.size and not is_bool_dtype(key.values):
raise ValueError("Must pass DataFrame with boolean values only")
return self.where(key)
def query(self, expr, inplace=False, **kwargs):
"""
Query the columns of a DataFrame with a boolean expression.
Parameters
----------
expr : str
The query string to evaluate. You can refer to variables
in the environment by prefixing them with an '@' character like
``@a + b``.
.. versionadded:: 0.25.0
You can refer to column names that contain spaces by surrounding
them in backticks.
For example, if one of your columns is called ``a a`` and you want
to sum it with ``b``, your query should be ```a a` + b``.
inplace : bool
Whether the query should modify the data in place or return
a modified copy.
**kwargs
See the documentation for :func:`eval` for complete details
on the keyword arguments accepted by :meth:`DataFrame.query`.
Returns
-------
DataFrame
DataFrame resulting from the provided query expression.
See Also
--------
eval : Evaluate a string describing operations on
DataFrame columns.
DataFrame.eval : Evaluate a string describing operations on
DataFrame columns.
Notes
-----
The result of the evaluation of this expression is first passed to
:attr:`DataFrame.loc` and if that fails because of a
multidimensional key (e.g., a DataFrame) then the result will be passed
to :meth:`DataFrame.__getitem__`.
This method uses the top-level :func:`eval` function to
evaluate the passed query.
The :meth:`~pandas.DataFrame.query` method uses a slightly
modified Python syntax by default. For example, the ``&`` and ``|``
(bitwise) operators have the precedence of their boolean cousins,
:keyword:`and` and :keyword:`or`. This *is* syntactically valid Python,
however the semantics are different.
You can change the semantics of the expression by passing the keyword
argument ``parser='python'``. This enforces the same semantics as
evaluation in Python space. Likewise, you can pass ``engine='python'``
to evaluate an expression using Python itself as a backend. This is not
recommended as it is inefficient compared to using ``numexpr`` as the
engine.
The :attr:`DataFrame.index` and
:attr:`DataFrame.columns` attributes of the
:class:`~pandas.DataFrame` instance are placed in the query namespace
by default, which allows you to treat both the index and columns of the
frame as a column in the frame.
The identifier ``index`` is used for the frame index; you can also
use the name of the index to identify it in a query. Please note that
Python keywords may not be used as identifiers.
For further details and examples see the ``query`` documentation in
:ref:`indexing <indexing.query>`.
Examples
--------
>>> df = pd.DataFrame({'A': range(1, 6),
... 'B': range(10, 0, -2),
... 'C C': range(10, 5, -1)})
>>> df
A B C C
0 1 10 10
1 2 8 9
2 3 6 8
3 4 4 7
4 5 2 6
>>> df.query('A > B')
A B C C
4 5 2 6
The previous expression is equivalent to
>>> df[df.A > df.B]
A B C C
4 5 2 6
For columns with spaces in their name, you can use backtick quoting.
>>> df.query('B == `C C`')
A B C C
0 1 10 10
The previous expression is equivalent to
>>> df[df.B == df['C C']]
A B C C
0 1 10 10
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not isinstance(expr, str):
msg = "expr must be a string to be evaluated, {0} given"
raise ValueError(msg.format(type(expr)))
kwargs["level"] = kwargs.pop("level", 0) + 1
kwargs["target"] = None
res = self.eval(expr, **kwargs)
try:
new_data = self.loc[res]
except ValueError:
# when res is multi-dimensional loc raises, but this is sometimes a
# valid query
new_data = self[res]
if inplace:
self._update_inplace(new_data)
else:
return new_data
def eval(self, expr, inplace=False, **kwargs):
"""
Evaluate a string describing operations on DataFrame columns.
Operates on columns only, not specific rows or elements. This allows
`eval` to run arbitrary code, which can make you vulnerable to code
injection if you pass user input to this function.
Parameters
----------
expr : str
The expression string to evaluate.
inplace : bool, default False
If the expression contains an assignment, whether to perform the
operation inplace and mutate the existing DataFrame. Otherwise,
a new DataFrame is returned.
kwargs : dict
See the documentation for :func:`eval` for complete details
on the keyword arguments accepted by
:meth:`~pandas.DataFrame.query`.
Returns
-------
ndarray, scalar, or pandas object
The result of the evaluation.
See Also
--------
DataFrame.query : Evaluates a boolean expression to query the columns
of a frame.
DataFrame.assign : Can evaluate an expression or function to create new
values for a column.
eval : Evaluate a Python expression as a string using various
backends.
Notes
-----
For more details see the API documentation for :func:`~eval`.
For detailed examples see :ref:`enhancing performance with eval
<enhancingperf.eval>`.
Examples
--------
>>> df = pd.DataFrame({'A': range(1, 6), 'B': range(10, 0, -2)})
>>> df
A B
0 1 10
1 2 8
2 3 6
3 4 4
4 5 2
>>> df.eval('A + B')
0 11
1 10
2 9
3 8
4 7
dtype: int64
Assignment is allowed though by default the original DataFrame is not
modified.
>>> df.eval('C = A + B')
A B C
0 1 10 11
1 2 8 10
2 3 6 9
3 4 4 8
4 5 2 7
>>> df
A B
0 1 10
1 2 8
2 3 6
3 4 4
4 5 2
Use ``inplace=True`` to modify the original DataFrame.
>>> df.eval('C = A + B', inplace=True)
>>> df
A B C
0 1 10 11
1 2 8 10
2 3 6 9
3 4 4 8
4 5 2 7
"""
from pandas.core.computation.eval import eval as _eval
inplace = validate_bool_kwarg(inplace, "inplace")
resolvers = kwargs.pop("resolvers", None)
kwargs["level"] = kwargs.pop("level", 0) + 1
if resolvers is None:
index_resolvers = self._get_index_resolvers()
column_resolvers = self._get_space_character_free_column_resolvers()
resolvers = column_resolvers, index_resolvers
if "target" not in kwargs:
kwargs["target"] = self
kwargs["resolvers"] = kwargs.get("resolvers", ()) + tuple(resolvers)
return _eval(expr, inplace=inplace, **kwargs)
def select_dtypes(self, include=None, exclude=None):
"""
Return a subset of the DataFrame's columns based on the column dtypes.
Parameters
----------
include, exclude : scalar or list-like
A selection of dtypes or strings to be included/excluded. At least
one of these parameters must be supplied.
Returns
-------
DataFrame
The subset of the frame including the dtypes in ``include`` and
excluding the dtypes in ``exclude``.
Raises
------
ValueError
* If both of ``include`` and ``exclude`` are empty
* If ``include`` and ``exclude`` have overlapping elements
* If any kind of string dtype is passed in.
Notes
-----
* To select all *numeric* types, use ``np.number`` or ``'number'``
* To select strings you must use the ``object`` dtype, but note that
this will return *all* object dtype columns
* See the `numpy dtype hierarchy
<http://docs.scipy.org/doc/numpy/reference/arrays.scalars.html>`__
* To select datetimes, use ``np.datetime64``, ``'datetime'`` or
``'datetime64'``
* To select timedeltas, use ``np.timedelta64``, ``'timedelta'`` or
``'timedelta64'``
* To select Pandas categorical dtypes, use ``'category'``
* To select Pandas datetimetz dtypes, use ``'datetimetz'`` (new in
0.20.0) or ``'datetime64[ns, tz]'``
Examples
--------
>>> df = pd.DataFrame({'a': [1, 2] * 3,
... 'b': [True, False] * 3,
... 'c': [1.0, 2.0] * 3})
>>> df
a b c
0 1 True 1.0
1 2 False 2.0
2 1 True 1.0
3 2 False 2.0
4 1 True 1.0
5 2 False 2.0
>>> df.select_dtypes(include='bool')
b
0 True
1 False
2 True
3 False
4 True
5 False
>>> df.select_dtypes(include=['float64'])
c
0 1.0
1 2.0
2 1.0
3 2.0
4 1.0
5 2.0
>>> df.select_dtypes(exclude=['int'])
b c
0 True 1.0
1 False 2.0
2 True 1.0
3 False 2.0
4 True 1.0
5 False 2.0
"""
def _get_info_slice(obj, indexer):
"""Slice the info axis of `obj` with `indexer`."""
if not hasattr(obj, "_info_axis_number"):
msg = "object of type {typ!r} has no info axis"
raise TypeError(msg.format(typ=type(obj).__name__))
slices = [slice(None)] * obj.ndim
slices[obj._info_axis_number] = indexer
return tuple(slices)
if not is_list_like(include):
include = (include,) if include is not None else ()
if not is_list_like(exclude):
exclude = (exclude,) if exclude is not None else ()
selection = tuple(map(frozenset, (include, exclude)))
if not any(selection):
raise ValueError("at least one of include or exclude must be " "nonempty")
# convert the myriad valid dtypes object to a single representation
include, exclude = map(
lambda x: frozenset(map(infer_dtype_from_object, x)), selection
)
for dtypes in (include, exclude):
invalidate_string_dtypes(dtypes)
# can't both include AND exclude!
if not include.isdisjoint(exclude):
raise ValueError(
"include and exclude overlap on {inc_ex}".format(
inc_ex=(include & exclude)
)
)
# empty include/exclude -> defaults to True
# three cases (we've already raised if both are empty)
# case 1: empty include, nonempty exclude
# we have True, True, ... True for include, same for exclude
# in the loop below we get the excluded
# and when we call '&' below we get only the excluded
# case 2: nonempty include, empty exclude
# same as case 1, but with include
# case 3: both nonempty
# the "union" of the logic of case 1 and case 2:
# we get the included and excluded, and return their logical and
include_these = Series(not bool(include), index=self.columns)
exclude_these = Series(not bool(exclude), index=self.columns)
def is_dtype_instance_mapper(idx, dtype):
return idx, functools.partial(issubclass, dtype.type)
for idx, f in itertools.starmap(
is_dtype_instance_mapper, enumerate(self.dtypes)
):
if include: # checks for the case of empty include or exclude
include_these.iloc[idx] = any(map(f, include))
if exclude:
exclude_these.iloc[idx] = not any(map(f, exclude))
dtype_indexer = include_these & exclude_these
return self.loc[_get_info_slice(self, dtype_indexer)]
def _box_item_values(self, key, values):
items = self.columns[self.columns.get_loc(key)]
if values.ndim == 2:
return self._constructor(values.T, columns=items, index=self.index)
else:
return self._box_col_values(values, items)
def _box_col_values(self, values, items):
"""
Provide boxed values for a column.
"""
klass = self._constructor_sliced
return klass(values, index=self.index, name=items, fastpath=True)
def __setitem__(self, key, value):
key = com.apply_if_callable(key, self)
# see if we can slice the rows
indexer = convert_to_index_sliceable(self, key)
if indexer is not None:
return self._setitem_slice(indexer, value)
if isinstance(key, DataFrame) or getattr(key, "ndim", None) == 2:
self._setitem_frame(key, value)
elif isinstance(key, (Series, np.ndarray, list, Index)):
self._setitem_array(key, value)
else:
# set column
self._set_item(key, value)
def _setitem_slice(self, key, value):
self._check_setitem_copy()
self.loc[key] = value
def _setitem_array(self, key, value):
# also raises Exception if object array with NA values
if com.is_bool_indexer(key):
if len(key) != len(self.index):
raise ValueError(
"Item wrong length %d instead of %d!" % (len(key), len(self.index))
)
key = check_bool_indexer(self.index, key)
indexer = key.nonzero()[0]
self._check_setitem_copy()
self.loc._setitem_with_indexer(indexer, value)
else:
if isinstance(value, DataFrame):
if len(value.columns) != len(key):
raise ValueError("Columns must be same length as key")
for k1, k2 in zip(key, value.columns):
self[k1] = value[k2]
else:
indexer = self.loc._get_listlike_indexer(
key, axis=1, raise_missing=False
)[1]
self._check_setitem_copy()
self.loc._setitem_with_indexer((slice(None), indexer), value)
def _setitem_frame(self, key, value):
# support boolean setting with DataFrame input, e.g.
# df[df > df2] = 0
if isinstance(key, np.ndarray):
if key.shape != self.shape:
raise ValueError("Array conditional must be same shape as self")
key = self._constructor(key, **self._construct_axes_dict())
if key.values.size and not is_bool_dtype(key.values):
raise TypeError(
"Must pass DataFrame or 2-d ndarray with boolean values only"
)
self._check_inplace_setting(value)
self._check_setitem_copy()
self._where(-key, value, inplace=True)
def _ensure_valid_index(self, value):
"""
Ensure that if we don't have an index, that we can create one from the
passed value.
"""
# GH5632, make sure that we are a Series convertible
if not len(self.index) and is_list_like(value):
try:
value = Series(value)
except (ValueError, NotImplementedError, TypeError):
raise ValueError(
"Cannot set a frame with no defined index "
"and a value that cannot be converted to a "
"Series"
)
self._data = self._data.reindex_axis(
value.index.copy(), axis=1, fill_value=np.nan
)
def _set_item(self, key, value):
"""
Add series to DataFrame in specified column.
If series is a numpy-array (not a Series/TimeSeries), it must be the
same length as the DataFrames index or an error will be thrown.
Series/TimeSeries will be conformed to the DataFrames index to
ensure homogeneity.
"""
self._ensure_valid_index(value)
value = self._sanitize_column(key, value)
NDFrame._set_item(self, key, value)
# check if we are modifying a copy
# try to set first as we want an invalid
# value exception to occur first
if len(self):
self._check_setitem_copy()
def insert(self, loc, column, value, allow_duplicates=False):
"""
Insert column into DataFrame at specified location.
Raises a ValueError if `column` is already contained in the DataFrame,
unless `allow_duplicates` is set to True.
Parameters
----------
loc : int
Insertion index. Must verify 0 <= loc <= len(columns)
column : string, number, or hashable object
label of the inserted column
value : int, Series, or array-like
allow_duplicates : bool, optional
"""
self._ensure_valid_index(value)
value = self._sanitize_column(column, value, broadcast=False)
self._data.insert(loc, column, value, allow_duplicates=allow_duplicates)
def assign(self, **kwargs):
r"""
Assign new columns to a DataFrame.
Returns a new object with all original columns in addition to new ones.
Existing columns that are re-assigned will be overwritten.
Parameters
----------
**kwargs : dict of {str: callable or Series}
The column names are keywords. If the values are
callable, they are computed on the DataFrame and
assigned to the new columns. The callable must not
change input DataFrame (though pandas doesn't check it).
If the values are not callable, (e.g. a Series, scalar, or array),
they are simply assigned.
Returns
-------
DataFrame
A new DataFrame with the new columns in addition to
all the existing columns.
Notes
-----
Assigning multiple columns within the same ``assign`` is possible.
For Python 3.6 and above, later items in '\*\*kwargs' may refer to
newly created or modified columns in 'df'; items are computed and
assigned into 'df' in order. For Python 3.5 and below, the order of
keyword arguments is not specified, you cannot refer to newly created
or modified columns. All items are computed first, and then assigned
in alphabetical order.
.. versionchanged :: 0.23.0
Keyword argument order is maintained for Python 3.6 and later.
Examples
--------
>>> df = pd.DataFrame({'temp_c': [17.0, 25.0]},
... index=['Portland', 'Berkeley'])
>>> df
temp_c
Portland 17.0
Berkeley 25.0
Where the value is a callable, evaluated on `df`:
>>> df.assign(temp_f=lambda x: x.temp_c * 9 / 5 + 32)
temp_c temp_f
Portland 17.0 62.6
Berkeley 25.0 77.0
Alternatively, the same behavior can be achieved by directly
referencing an existing Series or sequence:
>>> df.assign(temp_f=df['temp_c'] * 9 / 5 + 32)
temp_c temp_f
Portland 17.0 62.6
Berkeley 25.0 77.0
In Python 3.6+, you can create multiple columns within the same assign
where one of the columns depends on another one defined within the same
assign:
>>> df.assign(temp_f=lambda x: x['temp_c'] * 9 / 5 + 32,
... temp_k=lambda x: (x['temp_f'] + 459.67) * 5 / 9)
temp_c temp_f temp_k
Portland 17.0 62.6 290.15
Berkeley 25.0 77.0 298.15
"""
data = self.copy()
# >= 3.6 preserve order of kwargs
if PY36:
for k, v in kwargs.items():
data[k] = com.apply_if_callable(v, data)
else:
# <= 3.5: do all calculations first...
results = OrderedDict()
for k, v in kwargs.items():
results[k] = com.apply_if_callable(v, data)
# <= 3.5 and earlier
results = sorted(results.items())
# ... and then assign
for k, v in results:
data[k] = v
return data
def _sanitize_column(self, key, value, broadcast=True):
"""
Ensures new columns (which go into the BlockManager as new blocks) are
always copied and converted into an array.
Parameters
----------
key : object
value : scalar, Series, or array-like
broadcast : bool, default True
If ``key`` matches multiple duplicate column names in the
DataFrame, this parameter indicates whether ``value`` should be
tiled so that the returned array contains a (duplicated) column for
each occurrence of the key. If False, ``value`` will not be tiled.
Returns
-------
numpy.ndarray
"""
def reindexer(value):
# reindex if necessary
if value.index.equals(self.index) or not len(self.index):
value = value._values.copy()
else:
# GH 4107
try:
value = value.reindex(self.index)._values
except Exception as e:
# duplicate axis
if not value.index.is_unique:
raise e
# other
raise TypeError(
"incompatible index of inserted column " "with frame index"
)
return value
if isinstance(value, Series):
value = reindexer(value)
elif isinstance(value, DataFrame):
# align right-hand-side columns if self.columns
# is multi-index and self[key] is a sub-frame
if isinstance(self.columns, MultiIndex) and key in self.columns:
loc = self.columns.get_loc(key)
if isinstance(loc, (slice, Series, np.ndarray, Index)):
cols = maybe_droplevels(self.columns[loc], key)
if len(cols) and not cols.equals(value.columns):
value = value.reindex(cols, axis=1)
# now align rows
value = reindexer(value).T
elif isinstance(value, ExtensionArray):
# Explicitly copy here, instead of in sanitize_index,
# as sanitize_index won't copy an EA, even with copy=True
value = value.copy()
value = sanitize_index(value, self.index, copy=False)
elif isinstance(value, Index) or is_sequence(value):
# turn me into an ndarray
value = sanitize_index(value, self.index, copy=False)
if not isinstance(value, (np.ndarray, Index)):
if isinstance(value, list) and len(value) > 0:
value = maybe_convert_platform(value)
else:
value = com.asarray_tuplesafe(value)
elif value.ndim == 2:
value = value.copy().T
elif isinstance(value, Index):
value = value.copy(deep=True)
else:
value = value.copy()
# possibly infer to datetimelike
if is_object_dtype(value.dtype):
value = maybe_infer_to_datetimelike(value)
else:
# cast ignores pandas dtypes. so save the dtype first
infer_dtype, _ = infer_dtype_from_scalar(value, pandas_dtype=True)
# upcast
value = cast_scalar_to_array(len(self.index), value)
value = maybe_cast_to_datetime(value, infer_dtype)
# return internal types directly
if is_extension_type(value) or is_extension_array_dtype(value):
return value
# broadcast across multiple columns if necessary
if broadcast and key in self.columns and value.ndim == 1:
if not self.columns.is_unique or isinstance(self.columns, MultiIndex):
existing_piece = self[key]
if isinstance(existing_piece, DataFrame):
value = np.tile(value, (len(existing_piece.columns), 1))
return np.atleast_2d(np.asarray(value))
@property
def _series(self):
return {
item: Series(self._data.iget(idx), index=self.index, name=item)
for idx, item in enumerate(self.columns)
}
def lookup(self, row_labels, col_labels):
"""
Label-based "fancy indexing" function for DataFrame.
Given equal-length arrays of row and column labels, return an
array of the values corresponding to each (row, col) pair.
Parameters
----------
row_labels : sequence
The row labels to use for lookup
col_labels : sequence
The column labels to use for lookup
Returns
-------
numpy.ndarray
Notes
-----
Akin to::
result = [df.get_value(row, col)
for row, col in zip(row_labels, col_labels)]
Examples
--------
values : ndarray
The found values
"""
n = len(row_labels)
if n != len(col_labels):
raise ValueError("Row labels must have same size as column labels")
thresh = 1000
if not self._is_mixed_type or n > thresh:
values = self.values
ridx = self.index.get_indexer(row_labels)
cidx = self.columns.get_indexer(col_labels)
if (ridx == -1).any():
raise KeyError("One or more row labels was not found")
if (cidx == -1).any():
raise KeyError("One or more column labels was not found")
flat_index = ridx * len(self.columns) + cidx
result = values.flat[flat_index]
else:
result = np.empty(n, dtype="O")
for i, (r, c) in enumerate(zip(row_labels, col_labels)):
result[i] = self._get_value(r, c)
if is_object_dtype(result):
result = lib.maybe_convert_objects(result)
return result
# ----------------------------------------------------------------------
# Reindexing and alignment
def _reindex_axes(self, axes, level, limit, tolerance, method, fill_value, copy):
frame = self
columns = axes["columns"]
if columns is not None:
frame = frame._reindex_columns(
columns, method, copy, level, fill_value, limit, tolerance
)
index = axes["index"]
if index is not None:
frame = frame._reindex_index(
index, method, copy, level, fill_value, limit, tolerance
)
return frame
def _reindex_index(
self,
new_index,
method,
copy,
level,
fill_value=np.nan,
limit=None,
tolerance=None,
):
new_index, indexer = self.index.reindex(
new_index, method=method, level=level, limit=limit, tolerance=tolerance
)
return self._reindex_with_indexers(
{0: [new_index, indexer]},
copy=copy,
fill_value=fill_value,
allow_dups=False,
)
def _reindex_columns(
self,
new_columns,
method,
copy,
level,
fill_value=None,
limit=None,
tolerance=None,
):
new_columns, indexer = self.columns.reindex(
new_columns, method=method, level=level, limit=limit, tolerance=tolerance
)
return self._reindex_with_indexers(
{1: [new_columns, indexer]},
copy=copy,
fill_value=fill_value,
allow_dups=False,
)
def _reindex_multi(self, axes, copy, fill_value):
"""
We are guaranteed non-Nones in the axes.
"""
new_index, row_indexer = self.index.reindex(axes["index"])
new_columns, col_indexer = self.columns.reindex(axes["columns"])
if row_indexer is not None and col_indexer is not None:
indexer = row_indexer, col_indexer
new_values = algorithms.take_2d_multi(
self.values, indexer, fill_value=fill_value
)
return self._constructor(new_values, index=new_index, columns=new_columns)
else:
return self._reindex_with_indexers(
{0: [new_index, row_indexer], 1: [new_columns, col_indexer]},
copy=copy,
fill_value=fill_value,
)
@Appender(_shared_docs["align"] % _shared_doc_kwargs)
def align(
self,
other,
join="outer",
axis=None,
level=None,
copy=True,
fill_value=None,
method=None,
limit=None,
fill_axis=0,
broadcast_axis=None,
):
return super().align(
other,
join=join,
axis=axis,
level=level,
copy=copy,
fill_value=fill_value,
method=method,
limit=limit,
fill_axis=fill_axis,
broadcast_axis=broadcast_axis,
)
@Substitution(**_shared_doc_kwargs)
@Appender(NDFrame.reindex.__doc__)
@rewrite_axis_style_signature(
"labels",
[
("method", None),
("copy", True),
("level", None),
("fill_value", np.nan),
("limit", None),
("tolerance", None),
],
)
def reindex(self, *args, **kwargs):
axes = validate_axis_style_args(self, args, kwargs, "labels", "reindex")
kwargs.update(axes)
# Pop these, since the values are in `kwargs` under different names
kwargs.pop("axis", None)
kwargs.pop("labels", None)
return super().reindex(**kwargs)
def drop(
self,
labels=None,
axis=0,
index=None,
columns=None,
level=None,
inplace=False,
errors="raise",
):
"""
Drop specified labels from rows or columns.
Remove rows or columns by specifying label names and corresponding
axis, or by specifying directly index or column names. When using a
multi-index, labels on different levels can be removed by specifying
the level.
Parameters
----------
labels : single label or list-like
Index or column labels to drop.
axis : {0 or 'index', 1 or 'columns'}, default 0
Whether to drop labels from the index (0 or 'index') or
columns (1 or 'columns').
index : single label or list-like
Alternative to specifying axis (``labels, axis=0``
is equivalent to ``index=labels``).
.. versionadded:: 0.21.0
columns : single label or list-like
Alternative to specifying axis (``labels, axis=1``
is equivalent to ``columns=labels``).
.. versionadded:: 0.21.0
level : int or level name, optional
For MultiIndex, level from which the labels will be removed.
inplace : bool, default False
If True, do operation inplace and return None.
errors : {'ignore', 'raise'}, default 'raise'
If 'ignore', suppress error and only existing labels are
dropped.
Returns
-------
DataFrame
DataFrame without the removed index or column labels.
Raises
------
KeyError
If any of the labels is not found in the selected axis.
See Also
--------
DataFrame.loc : Label-location based indexer for selection by label.
DataFrame.dropna : Return DataFrame with labels on given axis omitted
where (all or any) data are missing.
DataFrame.drop_duplicates : Return DataFrame with duplicate rows
removed, optionally only considering certain columns.
Series.drop : Return Series with specified index labels removed.
Examples
--------
>>> df = pd.DataFrame(np.arange(12).reshape(3, 4),
... columns=['A', 'B', 'C', 'D'])
>>> df
A B C D
0 0 1 2 3
1 4 5 6 7
2 8 9 10 11
Drop columns
>>> df.drop(['B', 'C'], axis=1)
A D
0 0 3
1 4 7
2 8 11
>>> df.drop(columns=['B', 'C'])
A D
0 0 3
1 4 7
2 8 11
Drop a row by index
>>> df.drop([0, 1])
A B C D
2 8 9 10 11
Drop columns and/or rows of MultiIndex DataFrame
>>> midx = pd.MultiIndex(levels=[['lama', 'cow', 'falcon'],
... ['speed', 'weight', 'length']],
... codes=[[0, 0, 0, 1, 1, 1, 2, 2, 2],
... [0, 1, 2, 0, 1, 2, 0, 1, 2]])
>>> df = pd.DataFrame(index=midx, columns=['big', 'small'],
... data=[[45, 30], [200, 100], [1.5, 1], [30, 20],
... [250, 150], [1.5, 0.8], [320, 250],
... [1, 0.8], [0.3, 0.2]])
>>> df
big small
lama speed 45.0 30.0
weight 200.0 100.0
length 1.5 1.0
cow speed 30.0 20.0
weight 250.0 150.0
length 1.5 0.8
falcon speed 320.0 250.0
weight 1.0 0.8
length 0.3 0.2
>>> df.drop(index='cow', columns='small')
big
lama speed 45.0
weight 200.0
length 1.5
falcon speed 320.0
weight 1.0
length 0.3
>>> df.drop(index='length', level=1)
big small
lama speed 45.0 30.0
weight 200.0 100.0
cow speed 30.0 20.0
weight 250.0 150.0
falcon speed 320.0 250.0
weight 1.0 0.8
"""
return super().drop(
labels=labels,
axis=axis,
index=index,
columns=columns,
level=level,
inplace=inplace,
errors=errors,
)
@rewrite_axis_style_signature(
"mapper",
[("copy", True), ("inplace", False), ("level", None), ("errors", "ignore")],
)
def rename(self, *args, **kwargs):
"""
Alter axes labels.
Function / dict values must be unique (1-to-1). Labels not contained in
a dict / Series will be left as-is. Extra labels listed don't throw an
error.
See the :ref:`user guide <basics.rename>` for more.
Parameters
----------
mapper : dict-like or function
Dict-like or functions transformations to apply to
that axis' values. Use either ``mapper`` and ``axis`` to
specify the axis to target with ``mapper``, or ``index`` and
``columns``.
index : dict-like or function
Alternative to specifying axis (``mapper, axis=0``
is equivalent to ``index=mapper``).
columns : dict-like or function
Alternative to specifying axis (``mapper, axis=1``
is equivalent to ``columns=mapper``).
axis : int or str
Axis to target with ``mapper``. Can be either the axis name
('index', 'columns') or number (0, 1). The default is 'index'.
copy : bool, default True
Also copy underlying data.
inplace : bool, default False
Whether to return a new DataFrame. If True then value of copy is
ignored.
level : int or level name, default None
In case of a MultiIndex, only rename labels in the specified
level.
errors : {'ignore', 'raise'}, default 'ignore'
If 'raise', raise a `KeyError` when a dict-like `mapper`, `index`,
or `columns` contains labels that are not present in the Index
being transformed.
If 'ignore', existing keys will be renamed and extra keys will be
ignored.
Returns
-------
DataFrame
DataFrame with the renamed axis labels.
Raises
------
KeyError
If any of the labels is not found in the selected axis and
"errors='raise'".
See Also
--------
DataFrame.rename_axis : Set the name of the axis.
Examples
--------
``DataFrame.rename`` supports two calling conventions
* ``(index=index_mapper, columns=columns_mapper, ...)``
* ``(mapper, axis={'index', 'columns'}, ...)``
We *highly* recommend using keyword arguments to clarify your
intent.
Rename columns using a mapping:
>>> df = pd.DataFrame({"A": [1, 2, 3], "B": [4, 5, 6]})
>>> df.rename(columns={"A": "a", "B": "c"})
a c
0 1 4
1 2 5
2 3 6
Rename index using a mapping:
>>> df.rename(index={0: "x", 1: "y", 2: "z"})
A B
x 1 4
y 2 5
z 3 6
Cast index labels to a different type:
>>> df.index
RangeIndex(start=0, stop=3, step=1)
>>> df.rename(index=str).index
Index(['0', '1', '2'], dtype='object')
>>> df.rename(columns={"A": "a", "B": "b", "C": "c"}, errors="raise")
Traceback (most recent call last):
KeyError: ['C'] not found in axis
Using axis-style parameters
>>> df.rename(str.lower, axis='columns')
a b
0 1 4
1 2 5
2 3 6
>>> df.rename({1: 2, 2: 4}, axis='index')
A B
0 1 4
2 2 5
4 3 6
"""
axes = validate_axis_style_args(self, args, kwargs, "mapper", "rename")
kwargs.update(axes)
# Pop these, since the values are in `kwargs` under different names
kwargs.pop("axis", None)
kwargs.pop("mapper", None)
return super().rename(**kwargs)
@Substitution(**_shared_doc_kwargs)
@Appender(NDFrame.fillna.__doc__)
def fillna(
self,
value=None,
method=None,
axis=None,
inplace=False,
limit=None,
downcast=None,
**kwargs
):
return super().fillna(
value=value,
method=method,
axis=axis,
inplace=inplace,
limit=limit,
downcast=downcast,
**kwargs
)
@Appender(_shared_docs["replace"] % _shared_doc_kwargs)
def replace(
self,
to_replace=None,
value=None,
inplace=False,
limit=None,
regex=False,
method="pad",
):
return super().replace(
to_replace=to_replace,
value=value,
inplace=inplace,
limit=limit,
regex=regex,
method=method,
)
@Appender(_shared_docs["shift"] % _shared_doc_kwargs)
def shift(self, periods=1, freq=None, axis=0, fill_value=None):
return super().shift(
periods=periods, freq=freq, axis=axis, fill_value=fill_value
)
def set_index(
self, keys, drop=True, append=False, inplace=False, verify_integrity=False
):
"""
Set the DataFrame index using existing columns.
Set the DataFrame index (row labels) using one or more existing
columns or arrays (of the correct length). The index can replace the
existing index or expand on it.
Parameters
----------
keys : label or array-like or list of labels/arrays
This parameter can be either a single column key, a single array of
the same length as the calling DataFrame, or a list containing an
arbitrary combination of column keys and arrays. Here, "array"
encompasses :class:`Series`, :class:`Index`, ``np.ndarray``, and
instances of :class:`~collections.abc.Iterator`.
drop : bool, default True
Delete columns to be used as the new index.
append : bool, default False
Whether to append columns to existing index.
inplace : bool, default False
Modify the DataFrame in place (do not create a new object).
verify_integrity : bool, default False
Check the new index for duplicates. Otherwise defer the check until
necessary. Setting to False will improve the performance of this
method.
Returns
-------
DataFrame
Changed row labels.
See Also
--------
DataFrame.reset_index : Opposite of set_index.
DataFrame.reindex : Change to new indices or expand indices.
DataFrame.reindex_like : Change to same indices as other DataFrame.
Examples
--------
>>> df = pd.DataFrame({'month': [1, 4, 7, 10],
... 'year': [2012, 2014, 2013, 2014],
... 'sale': [55, 40, 84, 31]})
>>> df
month year sale
0 1 2012 55
1 4 2014 40
2 7 2013 84
3 10 2014 31
Set the index to become the 'month' column:
>>> df.set_index('month')
year sale
month
1 2012 55
4 2014 40
7 2013 84
10 2014 31
Create a MultiIndex using columns 'year' and 'month':
>>> df.set_index(['year', 'month'])
sale
year month
2012 1 55
2014 4 40
2013 7 84
2014 10 31
Create a MultiIndex using an Index and a column:
>>> df.set_index([pd.Index([1, 2, 3, 4]), 'year'])
month sale
year
1 2012 1 55
2 2014 4 40
3 2013 7 84
4 2014 10 31
Create a MultiIndex using two Series:
>>> s = pd.Series([1, 2, 3, 4])
>>> df.set_index([s, s**2])
month year sale
1 1 1 2012 55
2 4 4 2014 40
3 9 7 2013 84
4 16 10 2014 31
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if not isinstance(keys, list):
keys = [keys]
err_msg = (
'The parameter "keys" may be a column key, one-dimensional '
"array, or a list containing only valid column keys and "
"one-dimensional arrays."
)
missing = []
for col in keys:
if isinstance(
col, (ABCIndexClass, ABCSeries, np.ndarray, list, abc.Iterator)
):
# arrays are fine as long as they are one-dimensional
# iterators get converted to list below
if getattr(col, "ndim", 1) != 1:
raise ValueError(err_msg)
else:
# everything else gets tried as a key; see GH 24969
try:
found = col in self.columns
except TypeError:
raise TypeError(
err_msg + " Received column of " "type {}".format(type(col))
)
else:
if not found:
missing.append(col)
if missing:
raise KeyError("None of {} are in the columns".format(missing))
if inplace:
frame = self
else:
frame = self.copy()
arrays = []
names = []
if append:
names = [x for x in self.index.names]
if isinstance(self.index, ABCMultiIndex):
for i in range(self.index.nlevels):
arrays.append(self.index._get_level_values(i))
else:
arrays.append(self.index)
to_remove = []
for col in keys:
if isinstance(col, ABCMultiIndex):
for n in range(col.nlevels):
arrays.append(col._get_level_values(n))
names.extend(col.names)
elif isinstance(col, (ABCIndexClass, ABCSeries)):
# if Index then not MultiIndex (treated above)
arrays.append(col)
names.append(col.name)
elif isinstance(col, (list, np.ndarray)):
arrays.append(col)
names.append(None)
elif isinstance(col, abc.Iterator):
arrays.append(list(col))
names.append(None)
# from here, col can only be a column label
else:
arrays.append(frame[col]._values)
names.append(col)
if drop:
to_remove.append(col)
if len(arrays[-1]) != len(self):
# check newest element against length of calling frame, since
# ensure_index_from_sequences would not raise for append=False.
raise ValueError(
"Length mismatch: Expected {len_self} rows, "
"received array of length {len_col}".format(
len_self=len(self), len_col=len(arrays[-1])
)
)
index = ensure_index_from_sequences(arrays, names)
if verify_integrity and not index.is_unique:
duplicates = index[index.duplicated()].unique()
raise ValueError("Index has duplicate keys: {dup}".format(dup=duplicates))
# use set to handle duplicate column names gracefully in case of drop
for c in set(to_remove):
del frame[c]
# clear up memory usage
index._cleanup()
frame.index = index
if not inplace:
return frame
def reset_index(
self, level=None, drop=False, inplace=False, col_level=0, col_fill=""
):
"""
Reset the index, or a level of it.
Reset the index of the DataFrame, and use the default one instead.
If the DataFrame has a MultiIndex, this method can remove one or more
levels.
Parameters
----------
level : int, str, tuple, or list, default None
Only remove the given levels from the index. Removes all levels by
default.
drop : bool, default False
Do not try to insert index into dataframe columns. This resets
the index to the default integer index.
inplace : bool, default False
Modify the DataFrame in place (do not create a new object).
col_level : int or str, default 0
If the columns have multiple levels, determines which level the
labels are inserted into. By default it is inserted into the first
level.
col_fill : object, default ''
If the columns have multiple levels, determines how the other
levels are named. If None then the index name is repeated.
Returns
-------
DataFrame
DataFrame with the new index.
See Also
--------
DataFrame.set_index : Opposite of reset_index.
DataFrame.reindex : Change to new indices or expand indices.
DataFrame.reindex_like : Change to same indices as other DataFrame.
Examples
--------
>>> df = pd.DataFrame([('bird', 389.0),
... ('bird', 24.0),
... ('mammal', 80.5),
... ('mammal', np.nan)],
... index=['falcon', 'parrot', 'lion', 'monkey'],
... columns=('class', 'max_speed'))
>>> df
class max_speed
falcon bird 389.0
parrot bird 24.0
lion mammal 80.5
monkey mammal NaN
When we reset the index, the old index is added as a column, and a
new sequential index is used:
>>> df.reset_index()
index class max_speed
0 falcon bird 389.0
1 parrot bird 24.0
2 lion mammal 80.5
3 monkey mammal NaN
We can use the `drop` parameter to avoid the old index being added as
a column:
>>> df.reset_index(drop=True)
class max_speed
0 bird 389.0
1 bird 24.0
2 mammal 80.5
3 mammal NaN
You can also use `reset_index` with `MultiIndex`.
>>> index = pd.MultiIndex.from_tuples([('bird', 'falcon'),
... ('bird', 'parrot'),
... ('mammal', 'lion'),
... ('mammal', 'monkey')],
... names=['class', 'name'])
>>> columns = pd.MultiIndex.from_tuples([('speed', 'max'),
... ('species', 'type')])
>>> df = pd.DataFrame([(389.0, 'fly'),
... ( 24.0, 'fly'),
... ( 80.5, 'run'),
... (np.nan, 'jump')],
... index=index,
... columns=columns)
>>> df
speed species
max type
class name
bird falcon 389.0 fly
parrot 24.0 fly
mammal lion 80.5 run
monkey NaN jump
If the index has multiple levels, we can reset a subset of them:
>>> df.reset_index(level='class')
class speed species
max type
name
falcon bird 389.0 fly
parrot bird 24.0 fly
lion mammal 80.5 run
monkey mammal NaN jump
If we are not dropping the index, by default, it is placed in the top
level. We can place it in another level:
>>> df.reset_index(level='class', col_level=1)
speed species
class max type
name
falcon bird 389.0 fly
parrot bird 24.0 fly
lion mammal 80.5 run
monkey mammal NaN jump
When the index is inserted under another level, we can specify under
which one with the parameter `col_fill`:
>>> df.reset_index(level='class', col_level=1, col_fill='species')
species speed species
class max type
name
falcon bird 389.0 fly
parrot bird 24.0 fly
lion mammal 80.5 run
monkey mammal NaN jump
If we specify a nonexistent level for `col_fill`, it is created:
>>> df.reset_index(level='class', col_level=1, col_fill='genus')
genus speed species
class max type
name
falcon bird 389.0 fly
parrot bird 24.0 fly
lion mammal 80.5 run
monkey mammal NaN jump
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if inplace:
new_obj = self
else:
new_obj = self.copy()
def _maybe_casted_values(index, labels=None):
values = index._values
if not isinstance(index, (PeriodIndex, DatetimeIndex)):
if values.dtype == np.object_:
values = lib.maybe_convert_objects(values)
# if we have the labels, extract the values with a mask
if labels is not None:
mask = labels == -1
# we can have situations where the whole mask is -1,
# meaning there is nothing found in labels, so make all nan's
if mask.all():
values = np.empty(len(mask))
values.fill(np.nan)
else:
values = values.take(labels)
# TODO(https://github.com/pandas-dev/pandas/issues/24206)
# Push this into maybe_upcast_putmask?
# We can't pass EAs there right now. Looks a bit
# complicated.
# So we unbox the ndarray_values, op, re-box.
values_type = type(values)
values_dtype = values.dtype
if issubclass(values_type, DatetimeLikeArray):
values = values._data
if mask.any():
values, changed = maybe_upcast_putmask(values, mask, np.nan)
if issubclass(values_type, DatetimeLikeArray):
values = values_type(values, dtype=values_dtype)
return values
new_index = ibase.default_index(len(new_obj))
if level is not None:
if not isinstance(level, (tuple, list)):
level = [level]
level = [self.index._get_level_number(lev) for lev in level]
if len(level) < self.index.nlevels:
new_index = self.index.droplevel(level)
if not drop:
if isinstance(self.index, MultiIndex):
names = [
n if n is not None else ("level_%d" % i)
for (i, n) in enumerate(self.index.names)
]
to_insert = zip(self.index.levels, self.index.codes)
else:
default = "index" if "index" not in self else "level_0"
names = [default] if self.index.name is None else [self.index.name]
to_insert = ((self.index, None),)
multi_col = isinstance(self.columns, MultiIndex)
for i, (lev, lab) in reversed(list(enumerate(to_insert))):
if not (level is None or i in level):
continue
name = names[i]
if multi_col:
col_name = list(name) if isinstance(name, tuple) else [name]
if col_fill is None:
if len(col_name) not in (1, self.columns.nlevels):
raise ValueError(
"col_fill=None is incompatible "
"with incomplete column name "
"{}".format(name)
)
col_fill = col_name[0]
lev_num = self.columns._get_level_number(col_level)
name_lst = [col_fill] * lev_num + col_name
missing = self.columns.nlevels - len(name_lst)
name_lst += [col_fill] * missing
name = tuple(name_lst)
# to ndarray and maybe infer different dtype
level_values = _maybe_casted_values(lev, lab)
new_obj.insert(0, name, level_values)
new_obj.index = new_index
if not inplace:
return new_obj
# ----------------------------------------------------------------------
# Reindex-based selection methods
@Appender(_shared_docs["isna"] % _shared_doc_kwargs)
def isna(self):
return super().isna()
@Appender(_shared_docs["isna"] % _shared_doc_kwargs)
def isnull(self):
return super().isnull()
@Appender(_shared_docs["notna"] % _shared_doc_kwargs)
def notna(self):
return super().notna()
@Appender(_shared_docs["notna"] % _shared_doc_kwargs)
def notnull(self):
return super().notnull()
def dropna(self, axis=0, how="any", thresh=None, subset=None, inplace=False):
"""
Remove missing values.
See the :ref:`User Guide <missing_data>` for more on which values are
considered missing, and how to work with missing data.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
Determine if rows or columns which contain missing values are
removed.
* 0, or 'index' : Drop rows which contain missing values.
* 1, or 'columns' : Drop columns which contain missing value.
.. deprecated:: 0.23.0
Pass tuple or list to drop on multiple axes.
Only a single axis is allowed.
how : {'any', 'all'}, default 'any'
Determine if row or column is removed from DataFrame, when we have
at least one NA or all NA.
* 'any' : If any NA values are present, drop that row or column.
* 'all' : If all values are NA, drop that row or column.
thresh : int, optional
Require that many non-NA values.
subset : array-like, optional
Labels along other axis to consider, e.g. if you are dropping rows
these would be a list of columns to include.
inplace : bool, default False
If True, do operation inplace and return None.
Returns
-------
DataFrame
DataFrame with NA entries dropped from it.
See Also
--------
DataFrame.isna: Indicate missing values.
DataFrame.notna : Indicate existing (non-missing) values.
DataFrame.fillna : Replace missing values.
Series.dropna : Drop missing values.
Index.dropna : Drop missing indices.
Examples
--------
>>> df = pd.DataFrame({"name": ['Alfred', 'Batman', 'Catwoman'],
... "toy": [np.nan, 'Batmobile', 'Bullwhip'],
... "born": [pd.NaT, pd.Timestamp("1940-04-25"),
... pd.NaT]})
>>> df
name toy born
0 Alfred NaN NaT
1 Batman Batmobile 1940-04-25
2 Catwoman Bullwhip NaT
Drop the rows where at least one element is missing.
>>> df.dropna()
name toy born
1 Batman Batmobile 1940-04-25
Drop the columns where at least one element is missing.
>>> df.dropna(axis='columns')
name
0 Alfred
1 Batman
2 Catwoman
Drop the rows where all elements are missing.
>>> df.dropna(how='all')
name toy born
0 Alfred NaN NaT
1 Batman Batmobile 1940-04-25
2 Catwoman Bullwhip NaT
Keep only the rows with at least 2 non-NA values.
>>> df.dropna(thresh=2)
name toy born
1 Batman Batmobile 1940-04-25
2 Catwoman Bullwhip NaT
Define in which columns to look for missing values.
>>> df.dropna(subset=['name', 'born'])
name toy born
1 Batman Batmobile 1940-04-25
Keep the DataFrame with valid entries in the same variable.
>>> df.dropna(inplace=True)
>>> df
name toy born
1 Batman Batmobile 1940-04-25
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if isinstance(axis, (tuple, list)):
# GH20987
msg = (
"supplying multiple axes to axis is deprecated and "
"will be removed in a future version."
)
warnings.warn(msg, FutureWarning, stacklevel=2)
result = self
for ax in axis:
result = result.dropna(how=how, thresh=thresh, subset=subset, axis=ax)
else:
axis = self._get_axis_number(axis)
agg_axis = 1 - axis
agg_obj = self
if subset is not None:
ax = self._get_axis(agg_axis)
indices = ax.get_indexer_for(subset)
check = indices == -1
if check.any():
raise KeyError(list(np.compress(check, subset)))
agg_obj = self.take(indices, axis=agg_axis)
count = agg_obj.count(axis=agg_axis)
if thresh is not None:
mask = count >= thresh
elif how == "any":
mask = count == len(agg_obj._get_axis(agg_axis))
elif how == "all":
mask = count > 0
else:
if how is not None:
raise ValueError("invalid how option: {h}".format(h=how))
else:
raise TypeError("must specify how or thresh")
result = self.loc(axis=axis)[mask]
if inplace:
self._update_inplace(result)
else:
return result
def drop_duplicates(self, subset=None, keep="first", inplace=False):
"""
Return DataFrame with duplicate rows removed, optionally only
considering certain columns. Indexes, including time indexes
are ignored.
Parameters
----------
subset : column label or sequence of labels, optional
Only consider certain columns for identifying duplicates, by
default use all of the columns
keep : {'first', 'last', False}, default 'first'
- ``first`` : Drop duplicates except for the first occurrence.
- ``last`` : Drop duplicates except for the last occurrence.
- False : Drop all duplicates.
inplace : boolean, default False
Whether to drop duplicates in place or to return a copy
Returns
-------
DataFrame
"""
if self.empty:
return self.copy()
inplace = validate_bool_kwarg(inplace, "inplace")
duplicated = self.duplicated(subset, keep=keep)
if inplace:
inds, = (-duplicated)._ndarray_values.nonzero()
new_data = self._data.take(inds)
self._update_inplace(new_data)
else:
return self[-duplicated]
def duplicated(self, subset=None, keep="first"):
"""
Return boolean Series denoting duplicate rows, optionally only
considering certain columns.
Parameters
----------
subset : column label or sequence of labels, optional
Only consider certain columns for identifying duplicates, by
default use all of the columns
keep : {'first', 'last', False}, default 'first'
- ``first`` : Mark duplicates as ``True`` except for the
first occurrence.
- ``last`` : Mark duplicates as ``True`` except for the
last occurrence.
- False : Mark all duplicates as ``True``.
Returns
-------
Series
"""
from pandas.core.sorting import get_group_index
from pandas._libs.hashtable import duplicated_int64, _SIZE_HINT_LIMIT
if self.empty:
return Series(dtype=bool)
def f(vals):
labels, shape = algorithms.factorize(
vals, size_hint=min(len(self), _SIZE_HINT_LIMIT)
)
return labels.astype("i8", copy=False), len(shape)
if subset is None:
subset = self.columns
elif (
not np.iterable(subset)
or isinstance(subset, str)
or isinstance(subset, tuple)
and subset in self.columns
):
subset = (subset,)
# Verify all columns in subset exist in the queried dataframe
# Otherwise, raise a KeyError, same as if you try to __getitem__ with a
# key that doesn't exist.
diff = Index(subset).difference(self.columns)
if not diff.empty:
raise KeyError(diff)
vals = (col.values for name, col in self.items() if name in subset)
labels, shape = map(list, zip(*map(f, vals)))
ids = get_group_index(labels, shape, sort=False, xnull=False)
return Series(duplicated_int64(ids, keep), index=self.index)
# ----------------------------------------------------------------------
# Sorting
@Substitution(**_shared_doc_kwargs)
@Appender(NDFrame.sort_values.__doc__)
def sort_values(
self,
by,
axis=0,
ascending=True,
inplace=False,
kind="quicksort",
na_position="last",
):
inplace = validate_bool_kwarg(inplace, "inplace")
axis = self._get_axis_number(axis)
if not isinstance(by, list):
by = [by]
if is_sequence(ascending) and len(by) != len(ascending):
raise ValueError(
"Length of ascending (%d) != length of by (%d)"
% (len(ascending), len(by))
)
if len(by) > 1:
from pandas.core.sorting import lexsort_indexer
keys = [self._get_label_or_level_values(x, axis=axis) for x in by]
indexer = lexsort_indexer(keys, orders=ascending, na_position=na_position)
indexer = ensure_platform_int(indexer)
else:
from pandas.core.sorting import nargsort
by = by[0]
k = self._get_label_or_level_values(by, axis=axis)
if isinstance(ascending, (tuple, list)):
ascending = ascending[0]
indexer = nargsort(
k, kind=kind, ascending=ascending, na_position=na_position
)
new_data = self._data.take(
indexer, axis=self._get_block_manager_axis(axis), verify=False
)
if inplace:
return self._update_inplace(new_data)
else:
return self._constructor(new_data).__finalize__(self)
@Substitution(**_shared_doc_kwargs)
@Appender(NDFrame.sort_index.__doc__)
def sort_index(
self,
axis=0,
level=None,
ascending=True,
inplace=False,
kind="quicksort",
na_position="last",
sort_remaining=True,
by=None,
):
# TODO: this can be combined with Series.sort_index impl as
# almost identical
inplace = validate_bool_kwarg(inplace, "inplace")
# 10726
if by is not None:
warnings.warn(
"by argument to sort_index is deprecated, "
"please use .sort_values(by=...)",
FutureWarning,
stacklevel=2,
)
if level is not None:
raise ValueError("unable to simultaneously sort by and level")
return self.sort_values(by, axis=axis, ascending=ascending, inplace=inplace)
axis = self._get_axis_number(axis)
labels = self._get_axis(axis)
# make sure that the axis is lexsorted to start
# if not we need to reconstruct to get the correct indexer
labels = labels._sort_levels_monotonic()
if level is not None:
new_axis, indexer = labels.sortlevel(
level, ascending=ascending, sort_remaining=sort_remaining
)
elif isinstance(labels, MultiIndex):
from pandas.core.sorting import lexsort_indexer
indexer = lexsort_indexer(
labels._get_codes_for_sorting(),
orders=ascending,
na_position=na_position,
)
else:
from pandas.core.sorting import nargsort
# Check monotonic-ness before sort an index
# GH11080
if (ascending and labels.is_monotonic_increasing) or (
not ascending and labels.is_monotonic_decreasing
):
if inplace:
return
else:
return self.copy()
indexer = nargsort(
labels, kind=kind, ascending=ascending, na_position=na_position
)
baxis = self._get_block_manager_axis(axis)
new_data = self._data.take(indexer, axis=baxis, verify=False)
# reconstruct axis if needed
new_data.axes[baxis] = new_data.axes[baxis]._sort_levels_monotonic()
if inplace:
return self._update_inplace(new_data)
else:
return self._constructor(new_data).__finalize__(self)
def nlargest(self, n, columns, keep="first"):
"""
Return the first `n` rows ordered by `columns` in descending order.
Return the first `n` rows with the largest values in `columns`, in
descending order. The columns that are not specified are returned as
well, but not used for ordering.
This method is equivalent to
``df.sort_values(columns, ascending=False).head(n)``, but more
performant.
Parameters
----------
n : int
Number of rows to return.
columns : label or list of labels
Column label(s) to order by.
keep : {'first', 'last', 'all'}, default 'first'
Where there are duplicate values:
- `first` : prioritize the first occurrence(s)
- `last` : prioritize the last occurrence(s)
- ``all`` : do not drop any duplicates, even it means
selecting more than `n` items.
.. versionadded:: 0.24.0
Returns
-------
DataFrame
The first `n` rows ordered by the given columns in descending
order.
See Also
--------
DataFrame.nsmallest : Return the first `n` rows ordered by `columns` in
ascending order.
DataFrame.sort_values : Sort DataFrame by the values.
DataFrame.head : Return the first `n` rows without re-ordering.
Notes
-----
This function cannot be used with all column types. For example, when
specifying columns with `object` or `category` dtypes, ``TypeError`` is
raised.
Examples
--------
>>> df = pd.DataFrame({'population': [59000000, 65000000, 434000,
... 434000, 434000, 337000, 11300,
... 11300, 11300],
... 'GDP': [1937894, 2583560 , 12011, 4520, 12128,
... 17036, 182, 38, 311],
... 'alpha-2': ["IT", "FR", "MT", "MV", "BN",
... "IS", "NR", "TV", "AI"]},
... index=["Italy", "France", "Malta",
... "Maldives", "Brunei", "Iceland",
... "Nauru", "Tuvalu", "Anguilla"])
>>> df
population GDP alpha-2
Italy 59000000 1937894 IT
France 65000000 2583560 FR
Malta 434000 12011 MT
Maldives 434000 4520 MV
Brunei 434000 12128 BN
Iceland 337000 17036 IS
Nauru 11300 182 NR
Tuvalu 11300 38 TV
Anguilla 11300 311 AI
In the following example, we will use ``nlargest`` to select the three
rows having the largest values in column "population".
>>> df.nlargest(3, 'population')
population GDP alpha-2
France 65000000 2583560 FR
Italy 59000000 1937894 IT
Malta 434000 12011 MT
When using ``keep='last'``, ties are resolved in reverse order:
>>> df.nlargest(3, 'population', keep='last')
population GDP alpha-2
France 65000000 2583560 FR
Italy 59000000 1937894 IT
Brunei 434000 12128 BN
When using ``keep='all'``, all duplicate items are maintained:
>>> df.nlargest(3, 'population', keep='all')
population GDP alpha-2
France 65000000 2583560 FR
Italy 59000000 1937894 IT
Malta 434000 12011 MT
Maldives 434000 4520 MV
Brunei 434000 12128 BN
To order by the largest values in column "population" and then "GDP",
we can specify multiple columns like in the next example.
>>> df.nlargest(3, ['population', 'GDP'])
population GDP alpha-2
France 65000000 2583560 FR
Italy 59000000 1937894 IT
Brunei 434000 12128 BN
"""
return algorithms.SelectNFrame(self, n=n, keep=keep, columns=columns).nlargest()
def nsmallest(self, n, columns, keep="first"):
"""
Return the first `n` rows ordered by `columns` in ascending order.
Return the first `n` rows with the smallest values in `columns`, in
ascending order. The columns that are not specified are returned as
well, but not used for ordering.
This method is equivalent to
``df.sort_values(columns, ascending=True).head(n)``, but more
performant.
Parameters
----------
n : int
Number of items to retrieve.
columns : list or str
Column name or names to order by.
keep : {'first', 'last', 'all'}, default 'first'
Where there are duplicate values:
- ``first`` : take the first occurrence.
- ``last`` : take the last occurrence.
- ``all`` : do not drop any duplicates, even it means
selecting more than `n` items.
.. versionadded:: 0.24.0
Returns
-------
DataFrame
See Also
--------
DataFrame.nlargest : Return the first `n` rows ordered by `columns` in
descending order.
DataFrame.sort_values : Sort DataFrame by the values.
DataFrame.head : Return the first `n` rows without re-ordering.
Examples
--------
>>> df = pd.DataFrame({'population': [59000000, 65000000, 434000,
... 434000, 434000, 337000, 11300,
... 11300, 11300],
... 'GDP': [1937894, 2583560 , 12011, 4520, 12128,
... 17036, 182, 38, 311],
... 'alpha-2': ["IT", "FR", "MT", "MV", "BN",
... "IS", "NR", "TV", "AI"]},
... index=["Italy", "France", "Malta",
... "Maldives", "Brunei", "Iceland",
... "Nauru", "Tuvalu", "Anguilla"])
>>> df
population GDP alpha-2
Italy 59000000 1937894 IT
France 65000000 2583560 FR
Malta 434000 12011 MT
Maldives 434000 4520 MV
Brunei 434000 12128 BN
Iceland 337000 17036 IS
Nauru 11300 182 NR
Tuvalu 11300 38 TV
Anguilla 11300 311 AI
In the following example, we will use ``nsmallest`` to select the
three rows having the smallest values in column "a".
>>> df.nsmallest(3, 'population')
population GDP alpha-2
Nauru 11300 182 NR
Tuvalu 11300 38 TV
Anguilla 11300 311 AI
When using ``keep='last'``, ties are resolved in reverse order:
>>> df.nsmallest(3, 'population', keep='last')
population GDP alpha-2
Anguilla 11300 311 AI
Tuvalu 11300 38 TV
Nauru 11300 182 NR
When using ``keep='all'``, all duplicate items are maintained:
>>> df.nsmallest(3, 'population', keep='all')
population GDP alpha-2
Nauru 11300 182 NR
Tuvalu 11300 38 TV
Anguilla 11300 311 AI
To order by the largest values in column "a" and then "c", we can
specify multiple columns like in the next example.
>>> df.nsmallest(3, ['population', 'GDP'])
population GDP alpha-2
Tuvalu 11300 38 TV
Nauru 11300 182 NR
Anguilla 11300 311 AI
"""
return algorithms.SelectNFrame(
self, n=n, keep=keep, columns=columns
).nsmallest()
def swaplevel(self, i=-2, j=-1, axis=0):
"""
Swap levels i and j in a MultiIndex on a particular axis.
Parameters
----------
i, j : int, string (can be mixed)
Level of index to be swapped. Can pass level name as string.
Returns
-------
DataFrame
"""
result = self.copy()
axis = self._get_axis_number(axis)
if axis == 0:
result.index = result.index.swaplevel(i, j)
else:
result.columns = result.columns.swaplevel(i, j)
return result
def reorder_levels(self, order, axis=0):
"""
Rearrange index levels using input order. May not drop or
duplicate levels.
Parameters
----------
order : list of int or list of str
List representing new level order. Reference level by number
(position) or by key (label).
axis : int
Where to reorder levels.
Returns
-------
type of caller (new object)
"""
axis = self._get_axis_number(axis)
if not isinstance(self._get_axis(axis), MultiIndex): # pragma: no cover
raise TypeError("Can only reorder levels on a hierarchical axis.")
result = self.copy()
if axis == 0:
result.index = result.index.reorder_levels(order)
else:
result.columns = result.columns.reorder_levels(order)
return result
# ----------------------------------------------------------------------
# Arithmetic / combination related
def _combine_frame(self, other, func, fill_value=None, level=None):
this, other = self.align(other, join="outer", level=level, copy=False)
new_index, new_columns = this.index, this.columns
def _arith_op(left, right):
# for the mixed_type case where we iterate over columns,
# _arith_op(left, right) is equivalent to
# left._binop(right, func, fill_value=fill_value)
left, right = ops.fill_binop(left, right, fill_value)
return func(left, right)
if ops.should_series_dispatch(this, other, func):
# iterate over columns
return ops.dispatch_to_series(this, other, _arith_op)
else:
result = _arith_op(this.values, other.values)
return self._constructor(
result, index=new_index, columns=new_columns, copy=False
)
def _combine_match_index(self, other, func, level=None):
left, right = self.align(other, join="outer", axis=0, level=level, copy=False)
assert left.index.equals(right.index)
if left._is_mixed_type or right._is_mixed_type:
# operate column-wise; avoid costly object-casting in `.values`
return ops.dispatch_to_series(left, right, func)
else:
# fastpath --> operate directly on values
with np.errstate(all="ignore"):
new_data = func(left.values.T, right.values).T
return self._constructor(
new_data, index=left.index, columns=self.columns, copy=False
)
def _combine_match_columns(self, other, func, level=None):
assert isinstance(other, Series)
left, right = self.align(other, join="outer", axis=1, level=level, copy=False)
assert left.columns.equals(right.index)
return ops.dispatch_to_series(left, right, func, axis="columns")
def _combine_const(self, other, func):
assert lib.is_scalar(other) or np.ndim(other) == 0
return ops.dispatch_to_series(self, other, func)
def combine(self, other, func, fill_value=None, overwrite=True):
"""
Perform column-wise combine with another DataFrame.
Combines a DataFrame with `other` DataFrame using `func`
to element-wise combine columns. The row and column indexes of the
resulting DataFrame will be the union of the two.
Parameters
----------
other : DataFrame
The DataFrame to merge column-wise.
func : function
Function that takes two series as inputs and return a Series or a
scalar. Used to merge the two dataframes column by columns.
fill_value : scalar value, default None
The value to fill NaNs with prior to passing any column to the
merge func.
overwrite : bool, default True
If True, columns in `self` that do not exist in `other` will be
overwritten with NaNs.
Returns
-------
DataFrame
Combination of the provided DataFrames.
See Also
--------
DataFrame.combine_first : Combine two DataFrame objects and default to
non-null values in frame calling the method.
Examples
--------
Combine using a simple function that chooses the smaller column.
>>> df1 = pd.DataFrame({'A': [0, 0], 'B': [4, 4]})
>>> df2 = pd.DataFrame({'A': [1, 1], 'B': [3, 3]})
>>> take_smaller = lambda s1, s2: s1 if s1.sum() < s2.sum() else s2
>>> df1.combine(df2, take_smaller)
A B
0 0 3
1 0 3
Example using a true element-wise combine function.
>>> df1 = pd.DataFrame({'A': [5, 0], 'B': [2, 4]})
>>> df2 = pd.DataFrame({'A': [1, 1], 'B': [3, 3]})
>>> df1.combine(df2, np.minimum)
A B
0 1 2
1 0 3
Using `fill_value` fills Nones prior to passing the column to the
merge function.
>>> df1 = pd.DataFrame({'A': [0, 0], 'B': [None, 4]})
>>> df2 = pd.DataFrame({'A': [1, 1], 'B': [3, 3]})
>>> df1.combine(df2, take_smaller, fill_value=-5)
A B
0 0 -5.0
1 0 4.0
However, if the same element in both dataframes is None, that None
is preserved
>>> df1 = pd.DataFrame({'A': [0, 0], 'B': [None, 4]})
>>> df2 = pd.DataFrame({'A': [1, 1], 'B': [None, 3]})
>>> df1.combine(df2, take_smaller, fill_value=-5)
A B
0 0 -5.0
1 0 3.0
Example that demonstrates the use of `overwrite` and behavior when
the axis differ between the dataframes.
>>> df1 = pd.DataFrame({'A': [0, 0], 'B': [4, 4]})
>>> df2 = pd.DataFrame({'B': [3, 3], 'C': [-10, 1], }, index=[1, 2])
>>> df1.combine(df2, take_smaller)
A B C
0 NaN NaN NaN
1 NaN 3.0 -10.0
2 NaN 3.0 1.0
>>> df1.combine(df2, take_smaller, overwrite=False)
A B C
0 0.0 NaN NaN
1 0.0 3.0 -10.0
2 NaN 3.0 1.0
Demonstrating the preference of the passed in dataframe.
>>> df2 = pd.DataFrame({'B': [3, 3], 'C': [1, 1], }, index=[1, 2])
>>> df2.combine(df1, take_smaller)
A B C
0 0.0 NaN NaN
1 0.0 3.0 NaN
2 NaN 3.0 NaN
>>> df2.combine(df1, take_smaller, overwrite=False)
A B C
0 0.0 NaN NaN
1 0.0 3.0 1.0
2 NaN 3.0 1.0
"""
other_idxlen = len(other.index) # save for compare
this, other = self.align(other, copy=False)
new_index = this.index
if other.empty and len(new_index) == len(self.index):
return self.copy()
if self.empty and len(other) == other_idxlen:
return other.copy()
# sorts if possible
new_columns = this.columns.union(other.columns)
do_fill = fill_value is not None
result = {}
for col in new_columns:
series = this[col]
otherSeries = other[col]
this_dtype = series.dtype
other_dtype = otherSeries.dtype
this_mask = isna(series)
other_mask = isna(otherSeries)
# don't overwrite columns unnecessarily
# DO propagate if this column is not in the intersection
if not overwrite and other_mask.all():
result[col] = this[col].copy()
continue
if do_fill:
series = series.copy()
otherSeries = otherSeries.copy()
series[this_mask] = fill_value
otherSeries[other_mask] = fill_value
if col not in self.columns:
# If self DataFrame does not have col in other DataFrame,
# try to promote series, which is all NaN, as other_dtype.
new_dtype = other_dtype
try:
series = series.astype(new_dtype, copy=False)
except ValueError:
# e.g. new_dtype is integer types
pass
else:
# if we have different dtypes, possibly promote
new_dtype = find_common_type([this_dtype, other_dtype])
if not is_dtype_equal(this_dtype, new_dtype):
series = series.astype(new_dtype)
if not is_dtype_equal(other_dtype, new_dtype):
otherSeries = otherSeries.astype(new_dtype)
arr = func(series, otherSeries)
arr = maybe_downcast_to_dtype(arr, this_dtype)
result[col] = arr
# convert_objects just in case
return self._constructor(result, index=new_index, columns=new_columns)
def combine_first(self, other):
"""
Update null elements with value in the same location in `other`.
Combine two DataFrame objects by filling null values in one DataFrame
with non-null values from other DataFrame. The row and column indexes
of the resulting DataFrame will be the union of the two.
Parameters
----------
other : DataFrame
Provided DataFrame to use to fill null values.
Returns
-------
DataFrame
See Also
--------
DataFrame.combine : Perform series-wise operation on two DataFrames
using a given function.
Examples
--------
>>> df1 = pd.DataFrame({'A': [None, 0], 'B': [None, 4]})
>>> df2 = pd.DataFrame({'A': [1, 1], 'B': [3, 3]})
>>> df1.combine_first(df2)
A B
0 1.0 3.0
1 0.0 4.0
Null values still persist if the location of that null value
does not exist in `other`
>>> df1 = pd.DataFrame({'A': [None, 0], 'B': [4, None]})
>>> df2 = pd.DataFrame({'B': [3, 3], 'C': [1, 1]}, index=[1, 2])
>>> df1.combine_first(df2)
A B C
0 NaN 4.0 NaN
1 0.0 3.0 1.0
2 NaN 3.0 1.0
"""
import pandas.core.computation.expressions as expressions
def extract_values(arr):
# Does two things:
# 1. maybe gets the values from the Series / Index
# 2. convert datelike to i8
if isinstance(arr, (ABCIndexClass, ABCSeries)):
arr = arr._values
if needs_i8_conversion(arr):
if is_extension_array_dtype(arr.dtype):
arr = arr.asi8
else:
arr = arr.view("i8")
return arr
def combiner(x, y):
mask = isna(x)
if isinstance(mask, (ABCIndexClass, ABCSeries)):
mask = mask._values
x_values = extract_values(x)
y_values = extract_values(y)
# If the column y in other DataFrame is not in first DataFrame,
# just return y_values.
if y.name not in self.columns:
return y_values
return expressions.where(mask, y_values, x_values)
return self.combine(other, combiner, overwrite=False)
@deprecate_kwarg(
old_arg_name="raise_conflict",
new_arg_name="errors",
mapping={False: "ignore", True: "raise"},
)
def update(
self, other, join="left", overwrite=True, filter_func=None, errors="ignore"
):
"""
Modify in place using non-NA values from another DataFrame.
Aligns on indices. There is no return value.
Parameters
----------
other : DataFrame, or object coercible into a DataFrame
Should have at least one matching index/column label
with the original DataFrame. If a Series is passed,
its name attribute must be set, and that will be
used as the column name to align with the original DataFrame.
join : {'left'}, default 'left'
Only left join is implemented, keeping the index and columns of the
original object.
overwrite : bool, default True
How to handle non-NA values for overlapping keys:
* True: overwrite original DataFrame's values
with values from `other`.
* False: only update values that are NA in
the original DataFrame.
filter_func : callable(1d-array) -> bool 1d-array, optional
Can choose to replace values other than NA. Return True for values
that should be updated.
errors : {'raise', 'ignore'}, default 'ignore'
If 'raise', will raise a ValueError if the DataFrame and `other`
both contain non-NA data in the same place.
.. versionchanged :: 0.24.0
Changed from `raise_conflict=False|True`
to `errors='ignore'|'raise'`.
Returns
-------
None : method directly changes calling object
Raises
------
ValueError
* When `errors='raise'` and there's overlapping non-NA data.
* When `errors` is not either `'ignore'` or `'raise'`
NotImplementedError
* If `join != 'left'`
See Also
--------
dict.update : Similar method for dictionaries.
DataFrame.merge : For column(s)-on-columns(s) operations.
Examples
--------
>>> df = pd.DataFrame({'A': [1, 2, 3],
... 'B': [400, 500, 600]})
>>> new_df = pd.DataFrame({'B': [4, 5, 6],
... 'C': [7, 8, 9]})
>>> df.update(new_df)
>>> df
A B
0 1 4
1 2 5
2 3 6
The DataFrame's length does not increase as a result of the update,
only values at matching index/column labels are updated.
>>> df = pd.DataFrame({'A': ['a', 'b', 'c'],
... 'B': ['x', 'y', 'z']})
>>> new_df = pd.DataFrame({'B': ['d', 'e', 'f', 'g', 'h', 'i']})
>>> df.update(new_df)
>>> df
A B
0 a d
1 b e
2 c f
For Series, it's name attribute must be set.
>>> df = pd.DataFrame({'A': ['a', 'b', 'c'],
... 'B': ['x', 'y', 'z']})
>>> new_column = pd.Series(['d', 'e'], name='B', index=[0, 2])
>>> df.update(new_column)
>>> df
A B
0 a d
1 b y
2 c e
>>> df = pd.DataFrame({'A': ['a', 'b', 'c'],
... 'B': ['x', 'y', 'z']})
>>> new_df = pd.DataFrame({'B': ['d', 'e']}, index=[1, 2])
>>> df.update(new_df)
>>> df
A B
0 a x
1 b d
2 c e
If `other` contains NaNs the corresponding values are not updated
in the original dataframe.
>>> df = pd.DataFrame({'A': [1, 2, 3],
... 'B': [400, 500, 600]})
>>> new_df = pd.DataFrame({'B': [4, np.nan, 6]})
>>> df.update(new_df)
>>> df
A B
0 1 4.0
1 2 500.0
2 3 6.0
"""
import pandas.core.computation.expressions as expressions
# TODO: Support other joins
if join != "left": # pragma: no cover
raise NotImplementedError("Only left join is supported")
if errors not in ["ignore", "raise"]:
raise ValueError(
"The parameter errors must be either " "'ignore' or 'raise'"
)
if not isinstance(other, DataFrame):
other = DataFrame(other)
other = other.reindex_like(self)
for col in self.columns:
this = self[col]._values
that = other[col]._values
if filter_func is not None:
with np.errstate(all="ignore"):
mask = ~filter_func(this) | isna(that)
else:
if errors == "raise":
mask_this = notna(that)
mask_that = notna(this)
if any(mask_this & mask_that):
raise ValueError("Data overlaps.")
if overwrite:
mask = isna(that)
else:
mask = notna(this)
# don't overwrite columns unnecessarily
if mask.all():
continue
self[col] = expressions.where(mask, this, that)
# ----------------------------------------------------------------------
# Data reshaping
_shared_docs[
"pivot"
] = """
Return reshaped DataFrame organized by given index / column values.
Reshape data (produce a "pivot" table) based on column values. Uses
unique values from specified `index` / `columns` to form axes of the
resulting DataFrame. This function does not support data
aggregation, multiple values will result in a MultiIndex in the
columns. See the :ref:`User Guide <reshaping>` for more on reshaping.
Parameters
----------%s
index : string or object, optional
Column to use to make new frame's index. If None, uses
existing index.
columns : string or object
Column to use to make new frame's columns.
values : string, object or a list of the previous, optional
Column(s) to use for populating new frame's values. If not
specified, all remaining columns will be used and the result will
have hierarchically indexed columns.
.. versionchanged :: 0.23.0
Also accept list of column names.
Returns
-------
DataFrame
Returns reshaped DataFrame.
Raises
------
ValueError:
When there are any `index`, `columns` combinations with multiple
values. `DataFrame.pivot_table` when you need to aggregate.
See Also
--------
DataFrame.pivot_table : Generalization of pivot that can handle
duplicate values for one index/column pair.
DataFrame.unstack : Pivot based on the index values instead of a
column.
Notes
-----
For finer-tuned control, see hierarchical indexing documentation along
with the related stack/unstack methods.
Examples
--------
>>> df = pd.DataFrame({'foo': ['one', 'one', 'one', 'two', 'two',
... 'two'],
... 'bar': ['A', 'B', 'C', 'A', 'B', 'C'],
... 'baz': [1, 2, 3, 4, 5, 6],
... 'zoo': ['x', 'y', 'z', 'q', 'w', 't']})
>>> df
foo bar baz zoo
0 one A 1 x
1 one B 2 y
2 one C 3 z
3 two A 4 q
4 two B 5 w
5 two C 6 t
>>> df.pivot(index='foo', columns='bar', values='baz')
bar A B C
foo
one 1 2 3
two 4 5 6
>>> df.pivot(index='foo', columns='bar')['baz']
bar A B C
foo
one 1 2 3
two 4 5 6
>>> df.pivot(index='foo', columns='bar', values=['baz', 'zoo'])
baz zoo
bar A B C A B C
foo
one 1 2 3 x y z
two 4 5 6 q w t
A ValueError is raised if there are any duplicates.
>>> df = pd.DataFrame({"foo": ['one', 'one', 'two', 'two'],
... "bar": ['A', 'A', 'B', 'C'],
... "baz": [1, 2, 3, 4]})
>>> df
foo bar baz
0 one A 1
1 one A 2
2 two B 3
3 two C 4
Notice that the first two rows are the same for our `index`
and `columns` arguments.
>>> df.pivot(index='foo', columns='bar', values='baz')
Traceback (most recent call last):
...
ValueError: Index contains duplicate entries, cannot reshape
"""
@Substitution("")
@Appender(_shared_docs["pivot"])
def pivot(self, index=None, columns=None, values=None):
from pandas.core.reshape.pivot import pivot
return pivot(self, index=index, columns=columns, values=values)
_shared_docs[
"pivot_table"
] = """
Create a spreadsheet-style pivot table as a DataFrame. The levels in
the pivot table will be stored in MultiIndex objects (hierarchical
indexes) on the index and columns of the result DataFrame.
Parameters
----------%s
values : column to aggregate, optional
index : column, Grouper, array, or list of the previous
If an array is passed, it must be the same length as the data. The
list can contain any of the other types (except list).
Keys to group by on the pivot table index. If an array is passed,
it is being used as the same manner as column values.
columns : column, Grouper, array, or list of the previous
If an array is passed, it must be the same length as the data. The
list can contain any of the other types (except list).
Keys to group by on the pivot table column. If an array is passed,
it is being used as the same manner as column values.
aggfunc : function, list of functions, dict, default numpy.mean
If list of functions passed, the resulting pivot table will have
hierarchical columns whose top level are the function names
(inferred from the function objects themselves)
If dict is passed, the key is column to aggregate and value
is function or list of functions
fill_value : scalar, default None
Value to replace missing values with
margins : boolean, default False
Add all row / columns (e.g. for subtotal / grand totals)
dropna : boolean, default True
Do not include columns whose entries are all NaN
margins_name : string, default 'All'
Name of the row / column that will contain the totals
when margins is True.
observed : boolean, default False
This only applies if any of the groupers are Categoricals.
If True: only show observed values for categorical groupers.
If False: show all values for categorical groupers.
.. versionchanged :: 0.25.0
Returns
-------
DataFrame
See Also
--------
DataFrame.pivot : Pivot without aggregation that can handle
non-numeric data.
Examples
--------
>>> df = pd.DataFrame({"A": ["foo", "foo", "foo", "foo", "foo",
... "bar", "bar", "bar", "bar"],
... "B": ["one", "one", "one", "two", "two",
... "one", "one", "two", "two"],
... "C": ["small", "large", "large", "small",
... "small", "large", "small", "small",
... "large"],
... "D": [1, 2, 2, 3, 3, 4, 5, 6, 7],
... "E": [2, 4, 5, 5, 6, 6, 8, 9, 9]})
>>> df
A B C D E
0 foo one small 1 2
1 foo one large 2 4
2 foo one large 2 5
3 foo two small 3 5
4 foo two small 3 6
5 bar one large 4 6
6 bar one small 5 8
7 bar two small 6 9
8 bar two large 7 9
This first example aggregates values by taking the sum.
>>> table = pd.pivot_table(df, values='D', index=['A', 'B'],
... columns=['C'], aggfunc=np.sum)
>>> table
C large small
A B
bar one 4.0 5.0
two 7.0 6.0
foo one 4.0 1.0
two NaN 6.0
We can also fill missing values using the `fill_value` parameter.
>>> table = pd.pivot_table(df, values='D', index=['A', 'B'],
... columns=['C'], aggfunc=np.sum, fill_value=0)
>>> table
C large small
A B
bar one 4 5
two 7 6
foo one 4 1
two 0 6
The next example aggregates by taking the mean across multiple columns.
>>> table = pd.pivot_table(df, values=['D', 'E'], index=['A', 'C'],
... aggfunc={'D': np.mean,
... 'E': np.mean})
>>> table
D E
A C
bar large 5.500000 7.500000
small 5.500000 8.500000
foo large 2.000000 4.500000
small 2.333333 4.333333
We can also calculate multiple types of aggregations for any given
value column.
>>> table = pd.pivot_table(df, values=['D', 'E'], index=['A', 'C'],
... aggfunc={'D': np.mean,
... 'E': [min, max, np.mean]})
>>> table
D E
mean max mean min
A C
bar large 5.500000 9.0 7.500000 6.0
small 5.500000 9.0 8.500000 8.0
foo large 2.000000 5.0 4.500000 4.0
small 2.333333 6.0 4.333333 2.0
"""
@Substitution("")
@Appender(_shared_docs["pivot_table"])
def pivot_table(
self,
values=None,
index=None,
columns=None,
aggfunc="mean",
fill_value=None,
margins=False,
dropna=True,
margins_name="All",
observed=False,
):
from pandas.core.reshape.pivot import pivot_table
return pivot_table(
self,
values=values,
index=index,
columns=columns,
aggfunc=aggfunc,
fill_value=fill_value,
margins=margins,
dropna=dropna,
margins_name=margins_name,
observed=observed,
)
def stack(self, level=-1, dropna=True):
"""
Stack the prescribed level(s) from columns to index.
Return a reshaped DataFrame or Series having a multi-level
index with one or more new inner-most levels compared to the current
DataFrame. The new inner-most levels are created by pivoting the
columns of the current dataframe:
- if the columns have a single level, the output is a Series;
- if the columns have multiple levels, the new index
level(s) is (are) taken from the prescribed level(s) and
the output is a DataFrame.
The new index levels are sorted.
Parameters
----------
level : int, str, list, default -1
Level(s) to stack from the column axis onto the index
axis, defined as one index or label, or a list of indices
or labels.
dropna : bool, default True
Whether to drop rows in the resulting Frame/Series with
missing values. Stacking a column level onto the index
axis can create combinations of index and column values
that are missing from the original dataframe. See Examples
section.
Returns
-------
DataFrame or Series
Stacked dataframe or series.
See Also
--------
DataFrame.unstack : Unstack prescribed level(s) from index axis
onto column axis.
DataFrame.pivot : Reshape dataframe from long format to wide
format.
DataFrame.pivot_table : Create a spreadsheet-style pivot table
as a DataFrame.
Notes
-----
The function is named by analogy with a collection of books
being reorganized from being side by side on a horizontal
position (the columns of the dataframe) to being stacked
vertically on top of each other (in the index of the
dataframe).
Examples
--------
**Single level columns**
>>> df_single_level_cols = pd.DataFrame([[0, 1], [2, 3]],
... index=['cat', 'dog'],
... columns=['weight', 'height'])
Stacking a dataframe with a single level column axis returns a Series:
>>> df_single_level_cols
weight height
cat 0 1
dog 2 3
>>> df_single_level_cols.stack()
cat weight 0
height 1
dog weight 2
height 3
dtype: int64
**Multi level columns: simple case**
>>> multicol1 = pd.MultiIndex.from_tuples([('weight', 'kg'),
... ('weight', 'pounds')])
>>> df_multi_level_cols1 = pd.DataFrame([[1, 2], [2, 4]],
... index=['cat', 'dog'],
... columns=multicol1)
Stacking a dataframe with a multi-level column axis:
>>> df_multi_level_cols1
weight
kg pounds
cat 1 2
dog 2 4
>>> df_multi_level_cols1.stack()
weight
cat kg 1
pounds 2
dog kg 2
pounds 4
**Missing values**
>>> multicol2 = pd.MultiIndex.from_tuples([('weight', 'kg'),
... ('height', 'm')])
>>> df_multi_level_cols2 = pd.DataFrame([[1.0, 2.0], [3.0, 4.0]],
... index=['cat', 'dog'],
... columns=multicol2)
It is common to have missing values when stacking a dataframe
with multi-level columns, as the stacked dataframe typically
has more values than the original dataframe. Missing values
are filled with NaNs:
>>> df_multi_level_cols2
weight height
kg m
cat 1.0 2.0
dog 3.0 4.0
>>> df_multi_level_cols2.stack()
height weight
cat kg NaN 1.0
m 2.0 NaN
dog kg NaN 3.0
m 4.0 NaN
**Prescribing the level(s) to be stacked**
The first parameter controls which level or levels are stacked:
>>> df_multi_level_cols2.stack(0)
kg m
cat height NaN 2.0
weight 1.0 NaN
dog height NaN 4.0
weight 3.0 NaN
>>> df_multi_level_cols2.stack([0, 1])
cat height m 2.0
weight kg 1.0
dog height m 4.0
weight kg 3.0
dtype: float64
**Dropping missing values**
>>> df_multi_level_cols3 = pd.DataFrame([[None, 1.0], [2.0, 3.0]],
... index=['cat', 'dog'],
... columns=multicol2)
Note that rows where all values are missing are dropped by
default but this behaviour can be controlled via the dropna
keyword parameter:
>>> df_multi_level_cols3
weight height
kg m
cat NaN 1.0
dog 2.0 3.0
>>> df_multi_level_cols3.stack(dropna=False)
height weight
cat kg NaN NaN
m 1.0 NaN
dog kg NaN 2.0
m 3.0 NaN
>>> df_multi_level_cols3.stack(dropna=True)
height weight
cat m 1.0 NaN
dog kg NaN 2.0
m 3.0 NaN
"""
from pandas.core.reshape.reshape import stack, stack_multiple
if isinstance(level, (tuple, list)):
return stack_multiple(self, level, dropna=dropna)
else:
return stack(self, level, dropna=dropna)
def explode(self, column: Union[str, Tuple]) -> "DataFrame":
"""
Transform each element of a list-like to a row, replicating the
index values.
.. versionadded:: 0.25.0
Parameters
----------
column : str or tuple
Returns
-------
DataFrame
Exploded lists to rows of the subset columns;
index will be duplicated for these rows.
Raises
------
ValueError :
if columns of the frame are not unique.
See Also
--------
DataFrame.unstack : Pivot a level of the (necessarily hierarchical)
index labels
DataFrame.melt : Unpivot a DataFrame from wide format to long format
Series.explode : Explode a DataFrame from list-like columns to long format.
Notes
-----
This routine will explode list-likes including lists, tuples,
Series, and np.ndarray. The result dtype of the subset rows will
be object. Scalars will be returned unchanged. Empty list-likes will
result in a np.nan for that row.
Examples
--------
>>> df = pd.DataFrame({'A': [[1, 2, 3], 'foo', [], [3, 4]], 'B': 1})
>>> df
A B
0 [1, 2, 3] 1
1 foo 1
2 [] 1
3 [3, 4] 1
>>> df.explode('A')
A B
0 1 1
0 2 1
0 3 1
1 foo 1
2 NaN 1
3 3 1
3 4 1
"""
if not (is_scalar(column) or isinstance(column, tuple)):
raise ValueError("column must be a scalar")
if not self.columns.is_unique:
raise ValueError("columns must be unique")
result = self[column].explode()
return (
self.drop([column], axis=1)
.join(result)
.reindex(columns=self.columns, copy=False)
)
def unstack(self, level=-1, fill_value=None):
"""
Pivot a level of the (necessarily hierarchical) index labels, returning
a DataFrame having a new level of column labels whose inner-most level
consists of the pivoted index labels.
If the index is not a MultiIndex, the output will be a Series
(the analogue of stack when the columns are not a MultiIndex).
The level involved will automatically get sorted.
Parameters
----------
level : int, string, or list of these, default -1 (last level)
Level(s) of index to unstack, can pass level name
fill_value : replace NaN with this value if the unstack produces
missing values
Returns
-------
Series or DataFrame
See Also
--------
DataFrame.pivot : Pivot a table based on column values.
DataFrame.stack : Pivot a level of the column labels (inverse operation
from `unstack`).
Examples
--------
>>> index = pd.MultiIndex.from_tuples([('one', 'a'), ('one', 'b'),
... ('two', 'a'), ('two', 'b')])
>>> s = pd.Series(np.arange(1.0, 5.0), index=index)
>>> s
one a 1.0
b 2.0
two a 3.0
b 4.0
dtype: float64
>>> s.unstack(level=-1)
a b
one 1.0 2.0
two 3.0 4.0
>>> s.unstack(level=0)
one two
a 1.0 3.0
b 2.0 4.0
>>> df = s.unstack(level=0)
>>> df.unstack()
one a 1.0
b 2.0
two a 3.0
b 4.0
dtype: float64
"""
from pandas.core.reshape.reshape import unstack
return unstack(self, level, fill_value)
_shared_docs[
"melt"
] = """
Unpivot a DataFrame from wide format to long format, optionally
leaving identifier variables set.
This function is useful to massage a DataFrame into a format where one
or more columns are identifier variables (`id_vars`), while all other
columns, considered measured variables (`value_vars`), are "unpivoted" to
the row axis, leaving just two non-identifier columns, 'variable' and
'value'.
%(versionadded)s
Parameters
----------
frame : DataFrame
id_vars : tuple, list, or ndarray, optional
Column(s) to use as identifier variables.
value_vars : tuple, list, or ndarray, optional
Column(s) to unpivot. If not specified, uses all columns that
are not set as `id_vars`.
var_name : scalar
Name to use for the 'variable' column. If None it uses
``frame.columns.name`` or 'variable'.
value_name : scalar, default 'value'
Name to use for the 'value' column.
col_level : int or string, optional
If columns are a MultiIndex then use this level to melt.
Returns
-------
DataFrame
Unpivoted DataFrame.
See Also
--------
%(other)s
pivot_table
DataFrame.pivot
Series.explode
Examples
--------
>>> df = pd.DataFrame({'A': {0: 'a', 1: 'b', 2: 'c'},
... 'B': {0: 1, 1: 3, 2: 5},
... 'C': {0: 2, 1: 4, 2: 6}})
>>> df
A B C
0 a 1 2
1 b 3 4
2 c 5 6
>>> %(caller)sid_vars=['A'], value_vars=['B'])
A variable value
0 a B 1
1 b B 3
2 c B 5
>>> %(caller)sid_vars=['A'], value_vars=['B', 'C'])
A variable value
0 a B 1
1 b B 3
2 c B 5
3 a C 2
4 b C 4
5 c C 6
The names of 'variable' and 'value' columns can be customized:
>>> %(caller)sid_vars=['A'], value_vars=['B'],
... var_name='myVarname', value_name='myValname')
A myVarname myValname
0 a B 1
1 b B 3
2 c B 5
If you have multi-index columns:
>>> df.columns = [list('ABC'), list('DEF')]
>>> df
A B C
D E F
0 a 1 2
1 b 3 4
2 c 5 6
>>> %(caller)scol_level=0, id_vars=['A'], value_vars=['B'])
A variable value
0 a B 1
1 b B 3
2 c B 5
>>> %(caller)sid_vars=[('A', 'D')], value_vars=[('B', 'E')])
(A, D) variable_0 variable_1 value
0 a B E 1
1 b B E 3
2 c B E 5
"""
@Appender(
_shared_docs["melt"]
% dict(
caller="df.melt(", versionadded=".. versionadded:: 0.20.0\n", other="melt"
)
)
def melt(
self,
id_vars=None,
value_vars=None,
var_name=None,
value_name="value",
col_level=None,
):
from pandas.core.reshape.melt import melt
return melt(
self,
id_vars=id_vars,
value_vars=value_vars,
var_name=var_name,
value_name=value_name,
col_level=col_level,
)
# ----------------------------------------------------------------------
# Time series-related
def diff(self, periods=1, axis=0):
"""
First discrete difference of element.
Calculates the difference of a DataFrame element compared with another
element in the DataFrame (default is the element in the same column
of the previous row).
Parameters
----------
periods : int, default 1
Periods to shift for calculating difference, accepts negative
values.
axis : {0 or 'index', 1 or 'columns'}, default 0
Take difference over rows (0) or columns (1).
.. versionadded:: 0.16.1.
Returns
-------
DataFrame
See Also
--------
Series.diff: First discrete difference for a Series.
DataFrame.pct_change: Percent change over given number of periods.
DataFrame.shift: Shift index by desired number of periods with an
optional time freq.
Examples
--------
Difference with previous row
>>> df = pd.DataFrame({'a': [1, 2, 3, 4, 5, 6],
... 'b': [1, 1, 2, 3, 5, 8],
... 'c': [1, 4, 9, 16, 25, 36]})
>>> df
a b c
0 1 1 1
1 2 1 4
2 3 2 9
3 4 3 16
4 5 5 25
5 6 8 36
>>> df.diff()
a b c
0 NaN NaN NaN
1 1.0 0.0 3.0
2 1.0 1.0 5.0
3 1.0 1.0 7.0
4 1.0 2.0 9.0
5 1.0 3.0 11.0
Difference with previous column
>>> df.diff(axis=1)
a b c
0 NaN 0.0 0.0
1 NaN -1.0 3.0
2 NaN -1.0 7.0
3 NaN -1.0 13.0
4 NaN 0.0 20.0
5 NaN 2.0 28.0
Difference with 3rd previous row
>>> df.diff(periods=3)
a b c
0 NaN NaN NaN
1 NaN NaN NaN
2 NaN NaN NaN
3 3.0 2.0 15.0
4 3.0 4.0 21.0
5 3.0 6.0 27.0
Difference with following row
>>> df.diff(periods=-1)
a b c
0 -1.0 0.0 -3.0
1 -1.0 -1.0 -5.0
2 -1.0 -1.0 -7.0
3 -1.0 -2.0 -9.0
4 -1.0 -3.0 -11.0
5 NaN NaN NaN
"""
bm_axis = self._get_block_manager_axis(axis)
new_data = self._data.diff(n=periods, axis=bm_axis)
return self._constructor(new_data)
# ----------------------------------------------------------------------
# Function application
def _gotitem(
self,
key: Union[str, List[str]],
ndim: int,
subset: Optional[Union[Series, ABCDataFrame]] = None,
) -> Union[Series, ABCDataFrame]:
"""
Sub-classes to define. Return a sliced object.
Parameters
----------
key : string / list of selections
ndim : 1,2
requested ndim of result
subset : object, default None
subset to act on
"""
if subset is None:
subset = self
elif subset.ndim == 1: # is Series
return subset
# TODO: _shallow_copy(subset)?
return subset[key]
_agg_summary_and_see_also_doc = dedent(
"""
The aggregation operations are always performed over an axis, either the
index (default) or the column axis. This behavior is different from
`numpy` aggregation functions (`mean`, `median`, `prod`, `sum`, `std`,
`var`), where the default is to compute the aggregation of the flattened
array, e.g., ``numpy.mean(arr_2d)`` as opposed to
``numpy.mean(arr_2d, axis=0)``.
`agg` is an alias for `aggregate`. Use the alias.
See Also
--------
DataFrame.apply : Perform any type of operations.
DataFrame.transform : Perform transformation type operations.
core.groupby.GroupBy : Perform operations over groups.
core.resample.Resampler : Perform operations over resampled bins.
core.window.Rolling : Perform operations over rolling window.
core.window.Expanding : Perform operations over expanding window.
core.window.EWM : Perform operation over exponential weighted
window.
"""
)
_agg_examples_doc = dedent(
"""
Examples
--------
>>> df = pd.DataFrame([[1, 2, 3],
... [4, 5, 6],
... [7, 8, 9],
... [np.nan, np.nan, np.nan]],
... columns=['A', 'B', 'C'])
Aggregate these functions over the rows.
>>> df.agg(['sum', 'min'])
A B C
sum 12.0 15.0 18.0
min 1.0 2.0 3.0
Different aggregations per column.
>>> df.agg({'A' : ['sum', 'min'], 'B' : ['min', 'max']})
A B
max NaN 8.0
min 1.0 2.0
sum 12.0 NaN
Aggregate over the columns.
>>> df.agg("mean", axis="columns")
0 2.0
1 5.0
2 8.0
3 NaN
dtype: float64
"""
)
@Substitution(
see_also=_agg_summary_and_see_also_doc,
examples=_agg_examples_doc,
versionadded="\n.. versionadded:: 0.20.0\n",
**_shared_doc_kwargs
)
@Appender(_shared_docs["aggregate"])
def aggregate(self, func, axis=0, *args, **kwargs):
axis = self._get_axis_number(axis)
result = None
try:
result, how = self._aggregate(func, axis=axis, *args, **kwargs)
except TypeError:
pass
if result is None:
return self.apply(func, axis=axis, args=args, **kwargs)
return result
def _aggregate(self, arg, axis=0, *args, **kwargs):
if axis == 1:
# NDFrame.aggregate returns a tuple, and we need to transpose
# only result
result, how = self.T._aggregate(arg, *args, **kwargs)
result = result.T if result is not None else result
return result, how
return super()._aggregate(arg, *args, **kwargs)
agg = aggregate
@Appender(_shared_docs["transform"] % _shared_doc_kwargs)
def transform(self, func, axis=0, *args, **kwargs):
axis = self._get_axis_number(axis)
if axis == 1:
return self.T.transform(func, *args, **kwargs).T
return super().transform(func, *args, **kwargs)
def apply(
self,
func,
axis=0,
broadcast=None,
raw=False,
reduce=None,
result_type=None,
args=(),
**kwds
):
"""
Apply a function along an axis of the DataFrame.
Objects passed to the function are Series objects whose index is
either the DataFrame's index (``axis=0``) or the DataFrame's columns
(``axis=1``). By default (``result_type=None``), the final return type
is inferred from the return type of the applied function. Otherwise,
it depends on the `result_type` argument.
Parameters
----------
func : function
Function to apply to each column or row.
axis : {0 or 'index', 1 or 'columns'}, default 0
Axis along which the function is applied:
* 0 or 'index': apply function to each column.
* 1 or 'columns': apply function to each row.
broadcast : bool, optional
Only relevant for aggregation functions:
* ``False`` or ``None`` : returns a Series whose length is the
length of the index or the number of columns (based on the
`axis` parameter)
* ``True`` : results will be broadcast to the original shape
of the frame, the original index and columns will be retained.
.. deprecated:: 0.23.0
This argument will be removed in a future version, replaced
by result_type='broadcast'.
raw : bool, default False
* ``False`` : passes each row or column as a Series to the
function.
* ``True`` : the passed function will receive ndarray objects
instead.
If you are just applying a NumPy reduction function this will
achieve much better performance.
reduce : bool or None, default None
Try to apply reduction procedures. If the DataFrame is empty,
`apply` will use `reduce` to determine whether the result
should be a Series or a DataFrame. If ``reduce=None`` (the
default), `apply`'s return value will be guessed by calling
`func` on an empty Series
(note: while guessing, exceptions raised by `func` will be
ignored).
If ``reduce=True`` a Series will always be returned, and if
``reduce=False`` a DataFrame will always be returned.
.. deprecated:: 0.23.0
This argument will be removed in a future version, replaced
by ``result_type='reduce'``.
result_type : {'expand', 'reduce', 'broadcast', None}, default None
These only act when ``axis=1`` (columns):
* 'expand' : list-like results will be turned into columns.
* 'reduce' : returns a Series if possible rather than expanding
list-like results. This is the opposite of 'expand'.
* 'broadcast' : results will be broadcast to the original shape
of the DataFrame, the original index and columns will be
retained.
The default behaviour (None) depends on the return value of the
applied function: list-like results will be returned as a Series
of those. However if the apply function returns a Series these
are expanded to columns.
.. versionadded:: 0.23.0
args : tuple
Positional arguments to pass to `func` in addition to the
array/series.
**kwds
Additional keyword arguments to pass as keywords arguments to
`func`.
Returns
-------
Series or DataFrame
Result of applying ``func`` along the given axis of the
DataFrame.
See Also
--------
DataFrame.applymap: For elementwise operations.
DataFrame.aggregate: Only perform aggregating type operations.
DataFrame.transform: Only perform transforming type operations.
Notes
-----
In the current implementation apply calls `func` twice on the
first column/row to decide whether it can take a fast or slow
code path. This can lead to unexpected behavior if `func` has
side-effects, as they will take effect twice for the first
column/row.
Examples
--------
>>> df = pd.DataFrame([[4, 9]] * 3, columns=['A', 'B'])
>>> df
A B
0 4 9
1 4 9
2 4 9
Using a numpy universal function (in this case the same as
``np.sqrt(df)``):
>>> df.apply(np.sqrt)
A B
0 2.0 3.0
1 2.0 3.0
2 2.0 3.0
Using a reducing function on either axis
>>> df.apply(np.sum, axis=0)
A 12
B 27
dtype: int64
>>> df.apply(np.sum, axis=1)
0 13
1 13
2 13
dtype: int64
Returning a list-like will result in a Series
>>> df.apply(lambda x: [1, 2], axis=1)
0 [1, 2]
1 [1, 2]
2 [1, 2]
dtype: object
Passing result_type='expand' will expand list-like results
to columns of a Dataframe
>>> df.apply(lambda x: [1, 2], axis=1, result_type='expand')
0 1
0 1 2
1 1 2
2 1 2
Returning a Series inside the function is similar to passing
``result_type='expand'``. The resulting column names
will be the Series index.
>>> df.apply(lambda x: pd.Series([1, 2], index=['foo', 'bar']), axis=1)
foo bar
0 1 2
1 1 2
2 1 2
Passing ``result_type='broadcast'`` will ensure the same shape
result, whether list-like or scalar is returned by the function,
and broadcast it along the axis. The resulting column names will
be the originals.
>>> df.apply(lambda x: [1, 2], axis=1, result_type='broadcast')
A B
0 1 2
1 1 2
2 1 2
"""
from pandas.core.apply import frame_apply
op = frame_apply(
self,
func=func,
axis=axis,
broadcast=broadcast,
raw=raw,
reduce=reduce,
result_type=result_type,
args=args,
kwds=kwds,
)
return op.get_result()
def applymap(self, func):
"""
Apply a function to a Dataframe elementwise.
This method applies a function that accepts and returns a scalar
to every element of a DataFrame.
Parameters
----------
func : callable
Python function, returns a single value from a single value.
Returns
-------
DataFrame
Transformed DataFrame.
See Also
--------
DataFrame.apply : Apply a function along input axis of DataFrame.
Notes
-----
In the current implementation applymap calls `func` twice on the
first column/row to decide whether it can take a fast or slow
code path. This can lead to unexpected behavior if `func` has
side-effects, as they will take effect twice for the first
column/row.
Examples
--------
>>> df = pd.DataFrame([[1, 2.12], [3.356, 4.567]])
>>> df
0 1
0 1.000 2.120
1 3.356 4.567
>>> df.applymap(lambda x: len(str(x)))
0 1
0 3 4
1 5 5
Note that a vectorized version of `func` often exists, which will
be much faster. You could square each number elementwise.
>>> df.applymap(lambda x: x**2)
0 1
0 1.000000 4.494400
1 11.262736 20.857489
But it's better to avoid applymap in that case.
>>> df ** 2
0 1
0 1.000000 4.494400
1 11.262736 20.857489
"""
# if we have a dtype == 'M8[ns]', provide boxed values
def infer(x):
if x.empty:
return lib.map_infer(x, func)
return lib.map_infer(x.astype(object).values, func)
return self.apply(infer)
# ----------------------------------------------------------------------
# Merging / joining methods
def append(self, other, ignore_index=False, verify_integrity=False, sort=None):
"""
Append rows of `other` to the end of caller, returning a new object.
Columns in `other` that are not in the caller are added as new columns.
Parameters
----------
other : DataFrame or Series/dict-like object, or list of these
The data to append.
ignore_index : boolean, default False
If True, do not use the index labels.
verify_integrity : boolean, default False
If True, raise ValueError on creating index with duplicates.
sort : boolean, default None
Sort columns if the columns of `self` and `other` are not aligned.
The default sorting is deprecated and will change to not-sorting
in a future version of pandas. Explicitly pass ``sort=True`` to
silence the warning and sort. Explicitly pass ``sort=False`` to
silence the warning and not sort.
.. versionadded:: 0.23.0
Returns
-------
DataFrame
See Also
--------
concat : General function to concatenate DataFrame or Series objects.
Notes
-----
If a list of dict/series is passed and the keys are all contained in
the DataFrame's index, the order of the columns in the resulting
DataFrame will be unchanged.
Iteratively appending rows to a DataFrame can be more computationally
intensive than a single concatenate. A better solution is to append
those rows to a list and then concatenate the list with the original
DataFrame all at once.
Examples
--------
>>> df = pd.DataFrame([[1, 2], [3, 4]], columns=list('AB'))
>>> df
A B
0 1 2
1 3 4
>>> df2 = pd.DataFrame([[5, 6], [7, 8]], columns=list('AB'))
>>> df.append(df2)
A B
0 1 2
1 3 4
0 5 6
1 7 8
With `ignore_index` set to True:
>>> df.append(df2, ignore_index=True)
A B
0 1 2
1 3 4
2 5 6
3 7 8
The following, while not recommended methods for generating DataFrames,
show two ways to generate a DataFrame from multiple data sources.
Less efficient:
>>> df = pd.DataFrame(columns=['A'])
>>> for i in range(5):
... df = df.append({'A': i}, ignore_index=True)
>>> df
A
0 0
1 1
2 2
3 3
4 4
More efficient:
>>> pd.concat([pd.DataFrame([i], columns=['A']) for i in range(5)],
... ignore_index=True)
A
0 0
1 1
2 2
3 3
4 4
"""
if isinstance(other, (Series, dict)):
if isinstance(other, dict):
other = Series(other)
if other.name is None and not ignore_index:
raise TypeError(
"Can only append a Series if ignore_index=True"
" or if the Series has a name"
)
if other.name is None:
index = None
else:
# other must have the same index name as self, otherwise
# index name will be reset
index = Index([other.name], name=self.index.name)
idx_diff = other.index.difference(self.columns)
try:
combined_columns = self.columns.append(idx_diff)
except TypeError:
combined_columns = self.columns.astype(object).append(idx_diff)
other = other.reindex(combined_columns, copy=False)
other = DataFrame(
other.values.reshape((1, len(other))),
index=index,
columns=combined_columns,
)
other = other._convert(datetime=True, timedelta=True)
if not self.columns.equals(combined_columns):
self = self.reindex(columns=combined_columns)
elif isinstance(other, list) and not isinstance(other[0], DataFrame):
other = DataFrame(other)
if (self.columns.get_indexer(other.columns) >= 0).all():
other = other.reindex(columns=self.columns)
from pandas.core.reshape.concat import concat
if isinstance(other, (list, tuple)):
to_concat = [self] + other
else:
to_concat = [self, other]
return concat(
to_concat,
ignore_index=ignore_index,
verify_integrity=verify_integrity,
sort=sort,
)
def join(self, other, on=None, how="left", lsuffix="", rsuffix="", sort=False):
"""
Join columns of another DataFrame.
Join columns with `other` DataFrame either on index or on a key
column. Efficiently join multiple DataFrame objects by index at once by
passing a list.
Parameters
----------
other : DataFrame, Series, or list of DataFrame
Index should be similar to one of the columns in this one. If a
Series is passed, its name attribute must be set, and that will be
used as the column name in the resulting joined DataFrame.
on : str, list of str, or array-like, optional
Column or index level name(s) in the caller to join on the index
in `other`, otherwise joins index-on-index. If multiple
values given, the `other` DataFrame must have a MultiIndex. Can
pass an array as the join key if it is not already contained in
the calling DataFrame. Like an Excel VLOOKUP operation.
how : {'left', 'right', 'outer', 'inner'}, default 'left'
How to handle the operation of the two objects.
* left: use calling frame's index (or column if on is specified)
* right: use `other`'s index.
* outer: form union of calling frame's index (or column if on is
specified) with `other`'s index, and sort it.
lexicographically.
* inner: form intersection of calling frame's index (or column if
on is specified) with `other`'s index, preserving the order
of the calling's one.
lsuffix : str, default ''
Suffix to use from left frame's overlapping columns.
rsuffix : str, default ''
Suffix to use from right frame's overlapping columns.
sort : bool, default False
Order result DataFrame lexicographically by the join key. If False,
the order of the join key depends on the join type (how keyword).
Returns
-------
DataFrame
A dataframe containing columns from both the caller and `other`.
See Also
--------
DataFrame.merge : For column(s)-on-columns(s) operations.
Notes
-----
Parameters `on`, `lsuffix`, and `rsuffix` are not supported when
passing a list of `DataFrame` objects.
Support for specifying index levels as the `on` parameter was added
in version 0.23.0.
Examples
--------
>>> df = pd.DataFrame({'key': ['K0', 'K1', 'K2', 'K3', 'K4', 'K5'],
... 'A': ['A0', 'A1', 'A2', 'A3', 'A4', 'A5']})
>>> df
key A
0 K0 A0
1 K1 A1
2 K2 A2
3 K3 A3
4 K4 A4
5 K5 A5
>>> other = pd.DataFrame({'key': ['K0', 'K1', 'K2'],
... 'B': ['B0', 'B1', 'B2']})
>>> other
key B
0 K0 B0
1 K1 B1
2 K2 B2
Join DataFrames using their indexes.
>>> df.join(other, lsuffix='_caller', rsuffix='_other')
key_caller A key_other B
0 K0 A0 K0 B0
1 K1 A1 K1 B1
2 K2 A2 K2 B2
3 K3 A3 NaN NaN
4 K4 A4 NaN NaN
5 K5 A5 NaN NaN
If we want to join using the key columns, we need to set key to be
the index in both `df` and `other`. The joined DataFrame will have
key as its index.
>>> df.set_index('key').join(other.set_index('key'))
A B
key
K0 A0 B0
K1 A1 B1
K2 A2 B2
K3 A3 NaN
K4 A4 NaN
K5 A5 NaN
Another option to join using the key columns is to use the `on`
parameter. DataFrame.join always uses `other`'s index but we can use
any column in `df`. This method preserves the original DataFrame's
index in the result.
>>> df.join(other.set_index('key'), on='key')
key A B
0 K0 A0 B0
1 K1 A1 B1
2 K2 A2 B2
3 K3 A3 NaN
4 K4 A4 NaN
5 K5 A5 NaN
"""
# For SparseDataFrame's benefit
return self._join_compat(
other, on=on, how=how, lsuffix=lsuffix, rsuffix=rsuffix, sort=sort
)
def _join_compat(
self, other, on=None, how="left", lsuffix="", rsuffix="", sort=False
):
from pandas.core.reshape.merge import merge
from pandas.core.reshape.concat import concat
if isinstance(other, Series):
if other.name is None:
raise ValueError("Other Series must have a name")
other = DataFrame({other.name: other})
if isinstance(other, DataFrame):
return merge(
self,
other,
left_on=on,
how=how,
left_index=on is None,
right_index=True,
suffixes=(lsuffix, rsuffix),
sort=sort,
)
else:
if on is not None:
raise ValueError(
"Joining multiple DataFrames only supported" " for joining on index"
)
frames = [self] + list(other)
can_concat = all(df.index.is_unique for df in frames)
# join indexes only using concat
if can_concat:
if how == "left":
res = concat(frames, axis=1, join="outer", verify_integrity=True)
return res.reindex(self.index, copy=False)
else:
return concat(frames, axis=1, join=how, verify_integrity=True)
joined = frames[0]
for frame in frames[1:]:
joined = merge(
joined, frame, how=how, left_index=True, right_index=True
)
return joined
@Substitution("")
@Appender(_merge_doc, indents=2)
def merge(
self,
right,
how="inner",
on=None,
left_on=None,
right_on=None,
left_index=False,
right_index=False,
sort=False,
suffixes=("_x", "_y"),
copy=True,
indicator=False,
validate=None,
):
from pandas.core.reshape.merge import merge
return merge(
self,
right,
how=how,
on=on,
left_on=left_on,
right_on=right_on,
left_index=left_index,
right_index=right_index,
sort=sort,
suffixes=suffixes,
copy=copy,
indicator=indicator,
validate=validate,
)
def round(self, decimals=0, *args, **kwargs):
"""
Round a DataFrame to a variable number of decimal places.
Parameters
----------
decimals : int, dict, Series
Number of decimal places to round each column to. If an int is
given, round each column to the same number of places.
Otherwise dict and Series round to variable numbers of places.
Column names should be in the keys if `decimals` is a
dict-like, or in the index if `decimals` is a Series. Any
columns not included in `decimals` will be left as is. Elements
of `decimals` which are not columns of the input will be
ignored.
*args
Additional keywords have no effect but might be accepted for
compatibility with numpy.
**kwargs
Additional keywords have no effect but might be accepted for
compatibility with numpy.
Returns
-------
DataFrame
A DataFrame with the affected columns rounded to the specified
number of decimal places.
See Also
--------
numpy.around : Round a numpy array to the given number of decimals.
Series.round : Round a Series to the given number of decimals.
Examples
--------
>>> df = pd.DataFrame([(.21, .32), (.01, .67), (.66, .03), (.21, .18)],
... columns=['dogs', 'cats'])
>>> df
dogs cats
0 0.21 0.32
1 0.01 0.67
2 0.66 0.03
3 0.21 0.18
By providing an integer each column is rounded to the same number
of decimal places
>>> df.round(1)
dogs cats
0 0.2 0.3
1 0.0 0.7
2 0.7 0.0
3 0.2 0.2
With a dict, the number of places for specific columns can be
specified with the column names as key and the number of decimal
places as value
>>> df.round({'dogs': 1, 'cats': 0})
dogs cats
0 0.2 0.0
1 0.0 1.0
2 0.7 0.0
3 0.2 0.0
Using a Series, the number of places for specific columns can be
specified with the column names as index and the number of
decimal places as value
>>> decimals = pd.Series([0, 1], index=['cats', 'dogs'])
>>> df.round(decimals)
dogs cats
0 0.2 0.0
1 0.0 1.0
2 0.7 0.0
3 0.2 0.0
"""
from pandas.core.reshape.concat import concat
def _dict_round(df, decimals):
for col, vals in df.items():
try:
yield _series_round(vals, decimals[col])
except KeyError:
yield vals
def _series_round(s, decimals):
if is_integer_dtype(s) or is_float_dtype(s):
return s.round(decimals)
return s
nv.validate_round(args, kwargs)
if isinstance(decimals, (dict, Series)):
if isinstance(decimals, Series):
if not decimals.index.is_unique:
raise ValueError("Index of decimals must be unique")
new_cols = [col for col in _dict_round(self, decimals)]
elif is_integer(decimals):
# Dispatch to Series.round
new_cols = [_series_round(v, decimals) for _, v in self.items()]
else:
raise TypeError("decimals must be an integer, a dict-like or a " "Series")
if len(new_cols) > 0:
return self._constructor(
concat(new_cols, axis=1), index=self.index, columns=self.columns
)
else:
return self
# ----------------------------------------------------------------------
# Statistical methods, etc.
def corr(self, method="pearson", min_periods=1):
"""
Compute pairwise correlation of columns, excluding NA/null values.
Parameters
----------
method : {'pearson', 'kendall', 'spearman'} or callable
* pearson : standard correlation coefficient
* kendall : Kendall Tau correlation coefficient
* spearman : Spearman rank correlation
* callable: callable with input two 1d ndarrays
and returning a float. Note that the returned matrix from corr
will have 1 along the diagonals and will be symmetric
regardless of the callable's behavior
.. versionadded:: 0.24.0
min_periods : int, optional
Minimum number of observations required per pair of columns
to have a valid result. Currently only available for Pearson
and Spearman correlation.
Returns
-------
DataFrame
Correlation matrix.
See Also
--------
DataFrame.corrwith
Series.corr
Examples
--------
>>> def histogram_intersection(a, b):
... v = np.minimum(a, b).sum().round(decimals=1)
... return v
>>> df = pd.DataFrame([(.2, .3), (.0, .6), (.6, .0), (.2, .1)],
... columns=['dogs', 'cats'])
>>> df.corr(method=histogram_intersection)
dogs cats
dogs 1.0 0.3
cats 0.3 1.0
"""
numeric_df = self._get_numeric_data()
cols = numeric_df.columns
idx = cols.copy()
mat = numeric_df.values
if method == "pearson":
correl = libalgos.nancorr(ensure_float64(mat), minp=min_periods)
elif method == "spearman":
correl = libalgos.nancorr_spearman(ensure_float64(mat), minp=min_periods)
elif method == "kendall" or callable(method):
if min_periods is None:
min_periods = 1
mat = ensure_float64(mat).T
corrf = nanops.get_corr_func(method)
K = len(cols)
correl = np.empty((K, K), dtype=float)
mask = np.isfinite(mat)
for i, ac in enumerate(mat):
for j, bc in enumerate(mat):
if i > j:
continue
valid = mask[i] & mask[j]
if valid.sum() < min_periods:
c = np.nan
elif i == j:
c = 1.0
elif not valid.all():
c = corrf(ac[valid], bc[valid])
else:
c = corrf(ac, bc)
correl[i, j] = c
correl[j, i] = c
else:
raise ValueError(
"method must be either 'pearson', "
"'spearman', 'kendall', or a callable, "
"'{method}' was supplied".format(method=method)
)
return self._constructor(correl, index=idx, columns=cols)
def cov(self, min_periods=None):
"""
Compute pairwise covariance of columns, excluding NA/null values.
Compute the pairwise covariance among the series of a DataFrame.
The returned data frame is the `covariance matrix
<https://en.wikipedia.org/wiki/Covariance_matrix>`__ of the columns
of the DataFrame.
Both NA and null values are automatically excluded from the
calculation. (See the note below about bias from missing values.)
A threshold can be set for the minimum number of
observations for each value created. Comparisons with observations
below this threshold will be returned as ``NaN``.
This method is generally used for the analysis of time series data to
understand the relationship between different measures
across time.
Parameters
----------
min_periods : int, optional
Minimum number of observations required per pair of columns
to have a valid result.
Returns
-------
DataFrame
The covariance matrix of the series of the DataFrame.
See Also
--------
Series.cov : Compute covariance with another Series.
core.window.EWM.cov: Exponential weighted sample covariance.
core.window.Expanding.cov : Expanding sample covariance.
core.window.Rolling.cov : Rolling sample covariance.
Notes
-----
Returns the covariance matrix of the DataFrame's time series.
The covariance is normalized by N-1.
For DataFrames that have Series that are missing data (assuming that
data is `missing at random
<https://en.wikipedia.org/wiki/Missing_data#Missing_at_random>`__)
the returned covariance matrix will be an unbiased estimate
of the variance and covariance between the member Series.
However, for many applications this estimate may not be acceptable
because the estimate covariance matrix is not guaranteed to be positive
semi-definite. This could lead to estimate correlations having
absolute values which are greater than one, and/or a non-invertible
covariance matrix. See `Estimation of covariance matrices
<http://en.wikipedia.org/w/index.php?title=Estimation_of_covariance_
matrices>`__ for more details.
Examples
--------
>>> df = pd.DataFrame([(1, 2), (0, 3), (2, 0), (1, 1)],
... columns=['dogs', 'cats'])
>>> df.cov()
dogs cats
dogs 0.666667 -1.000000
cats -1.000000 1.666667
>>> np.random.seed(42)
>>> df = pd.DataFrame(np.random.randn(1000, 5),
... columns=['a', 'b', 'c', 'd', 'e'])
>>> df.cov()
a b c d e
a 0.998438 -0.020161 0.059277 -0.008943 0.014144
b -0.020161 1.059352 -0.008543 -0.024738 0.009826
c 0.059277 -0.008543 1.010670 -0.001486 -0.000271
d -0.008943 -0.024738 -0.001486 0.921297 -0.013692
e 0.014144 0.009826 -0.000271 -0.013692 0.977795
**Minimum number of periods**
This method also supports an optional ``min_periods`` keyword
that specifies the required minimum number of non-NA observations for
each column pair in order to have a valid result:
>>> np.random.seed(42)
>>> df = pd.DataFrame(np.random.randn(20, 3),
... columns=['a', 'b', 'c'])
>>> df.loc[df.index[:5], 'a'] = np.nan
>>> df.loc[df.index[5:10], 'b'] = np.nan
>>> df.cov(min_periods=12)
a b c
a 0.316741 NaN -0.150812
b NaN 1.248003 0.191417
c -0.150812 0.191417 0.895202
"""
numeric_df = self._get_numeric_data()
cols = numeric_df.columns
idx = cols.copy()
mat = numeric_df.values
if notna(mat).all():
if min_periods is not None and min_periods > len(mat):
baseCov = np.empty((mat.shape[1], mat.shape[1]))
baseCov.fill(np.nan)
else:
baseCov = np.cov(mat.T)
baseCov = baseCov.reshape((len(cols), len(cols)))
else:
baseCov = libalgos.nancorr(ensure_float64(mat), cov=True, minp=min_periods)
return self._constructor(baseCov, index=idx, columns=cols)
def corrwith(self, other, axis=0, drop=False, method="pearson"):
"""
Compute pairwise correlation between rows or columns of DataFrame
with rows or columns of Series or DataFrame. DataFrames are first
aligned along both axes before computing the correlations.
Parameters
----------
other : DataFrame, Series
Object with which to compute correlations.
axis : {0 or 'index', 1 or 'columns'}, default 0
0 or 'index' to compute column-wise, 1 or 'columns' for row-wise.
drop : bool, default False
Drop missing indices from result.
method : {'pearson', 'kendall', 'spearman'} or callable
* pearson : standard correlation coefficient
* kendall : Kendall Tau correlation coefficient
* spearman : Spearman rank correlation
* callable: callable with input two 1d ndarrays
and returning a float
.. versionadded:: 0.24.0
Returns
-------
Series
Pairwise correlations.
See Also
--------
DataFrame.corr
"""
axis = self._get_axis_number(axis)
this = self._get_numeric_data()
if isinstance(other, Series):
return this.apply(lambda x: other.corr(x, method=method), axis=axis)
other = other._get_numeric_data()
left, right = this.align(other, join="inner", copy=False)
if axis == 1:
left = left.T
right = right.T
if method == "pearson":
# mask missing values
left = left + right * 0
right = right + left * 0
# demeaned data
ldem = left - left.mean()
rdem = right - right.mean()
num = (ldem * rdem).sum()
dom = (left.count() - 1) * left.std() * right.std()
correl = num / dom
elif method in ["kendall", "spearman"] or callable(method):
def c(x):
return nanops.nancorr(x[0], x[1], method=method)
correl = Series(
map(c, zip(left.values.T, right.values.T)), index=left.columns
)
else:
raise ValueError(
"Invalid method {method} was passed, "
"valid methods are: 'pearson', 'kendall', "
"'spearman', or callable".format(method=method)
)
if not drop:
# Find non-matching labels along the given axis
# and append missing correlations (GH 22375)
raxis = 1 if axis == 0 else 0
result_index = this._get_axis(raxis).union(other._get_axis(raxis))
idx_diff = result_index.difference(correl.index)
if len(idx_diff) > 0:
correl = correl.append(Series([np.nan] * len(idx_diff), index=idx_diff))
return correl
# ----------------------------------------------------------------------
# ndarray-like stats methods
def count(self, axis=0, level=None, numeric_only=False):
"""
Count non-NA cells for each column or row.
The values `None`, `NaN`, `NaT`, and optionally `numpy.inf` (depending
on `pandas.options.mode.use_inf_as_na`) are considered NA.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
If 0 or 'index' counts are generated for each column.
If 1 or 'columns' counts are generated for each **row**.
level : int or str, optional
If the axis is a `MultiIndex` (hierarchical), count along a
particular `level`, collapsing into a `DataFrame`.
A `str` specifies the level name.
numeric_only : bool, default False
Include only `float`, `int` or `boolean` data.
Returns
-------
Series or DataFrame
For each column/row the number of non-NA/null entries.
If `level` is specified returns a `DataFrame`.
See Also
--------
Series.count: Number of non-NA elements in a Series.
DataFrame.shape: Number of DataFrame rows and columns (including NA
elements).
DataFrame.isna: Boolean same-sized DataFrame showing places of NA
elements.
Examples
--------
Constructing DataFrame from a dictionary:
>>> df = pd.DataFrame({"Person":
... ["John", "Myla", "Lewis", "John", "Myla"],
... "Age": [24., np.nan, 21., 33, 26],
... "Single": [False, True, True, True, False]})
>>> df
Person Age Single
0 John 24.0 False
1 Myla NaN True
2 Lewis 21.0 True
3 John 33.0 True
4 Myla 26.0 False
Notice the uncounted NA values:
>>> df.count()
Person 5
Age 4
Single 5
dtype: int64
Counts for each **row**:
>>> df.count(axis='columns')
0 3
1 2
2 3
3 3
4 3
dtype: int64
Counts for one level of a `MultiIndex`:
>>> df.set_index(["Person", "Single"]).count(level="Person")
Age
Person
John 2
Lewis 1
Myla 1
"""
axis = self._get_axis_number(axis)
if level is not None:
return self._count_level(level, axis=axis, numeric_only=numeric_only)
if numeric_only:
frame = self._get_numeric_data()
else:
frame = self
# GH #423
if len(frame._get_axis(axis)) == 0:
result = Series(0, index=frame._get_agg_axis(axis))
else:
if frame._is_mixed_type or frame._data.any_extension_types:
# the or any_extension_types is really only hit for single-
# column frames with an extension array
result = notna(frame).sum(axis=axis)
else:
# GH13407
series_counts = notna(frame).sum(axis=axis)
counts = series_counts.values
result = Series(counts, index=frame._get_agg_axis(axis))
return result.astype("int64")
def _count_level(self, level, axis=0, numeric_only=False):
if numeric_only:
frame = self._get_numeric_data()
else:
frame = self
count_axis = frame._get_axis(axis)
agg_axis = frame._get_agg_axis(axis)
if not isinstance(count_axis, MultiIndex):
raise TypeError(
"Can only count levels on hierarchical "
"{ax}.".format(ax=self._get_axis_name(axis))
)
if frame._is_mixed_type:
# Since we have mixed types, calling notna(frame.values) might
# upcast everything to object
mask = notna(frame).values
else:
# But use the speedup when we have homogeneous dtypes
mask = notna(frame.values)
if axis == 1:
# We're transposing the mask rather than frame to avoid potential
# upcasts to object, which induces a ~20x slowdown
mask = mask.T
if isinstance(level, str):
level = count_axis._get_level_number(level)
level_index = count_axis.levels[level]
level_codes = ensure_int64(count_axis.codes[level])
counts = lib.count_level_2d(mask, level_codes, len(level_index), axis=0)
result = DataFrame(counts, index=level_index, columns=agg_axis)
if axis == 1:
# Undo our earlier transpose
return result.T
else:
return result
def _reduce(
self, op, name, axis=0, skipna=True, numeric_only=None, filter_type=None, **kwds
):
if axis is None and filter_type == "bool":
labels = None
constructor = None
else:
# TODO: Make other agg func handle axis=None properly
axis = self._get_axis_number(axis)
labels = self._get_agg_axis(axis)
constructor = self._constructor
def f(x):
return op(x, axis=axis, skipna=skipna, **kwds)
# exclude timedelta/datetime unless we are uniform types
if (
axis == 1
and self._is_datelike_mixed_type
and (
not self._is_homogeneous_type
and not is_datetime64tz_dtype(self.dtypes[0])
)
):
numeric_only = True
if numeric_only is None:
try:
values = self.values
result = f(values)
if filter_type == "bool" and is_object_dtype(values) and axis is None:
# work around https://github.com/numpy/numpy/issues/10489
# TODO: combine with hasattr(result, 'dtype') further down
# hard since we don't have `values` down there.
result = np.bool_(result)
except Exception as e:
# try by-column first
if filter_type is None and axis == 0:
try:
# this can end up with a non-reduction
# but not always. if the types are mixed
# with datelike then need to make sure a series
# we only end up here if we have not specified
# numeric_only and yet we have tried a
# column-by-column reduction, where we have mixed type.
# So let's just do what we can
from pandas.core.apply import frame_apply
opa = frame_apply(
self, func=f, result_type="expand", ignore_failures=True
)
result = opa.get_result()
if result.ndim == self.ndim:
result = result.iloc[0]
return result
except Exception:
pass
if filter_type is None or filter_type == "numeric":
data = self._get_numeric_data()
elif filter_type == "bool":
data = self._get_bool_data()
else: # pragma: no cover
e = NotImplementedError(
"Handling exception with filter_type {f} not"
"implemented.".format(f=filter_type)
)
raise_with_traceback(e)
with np.errstate(all="ignore"):
result = f(data.values)
labels = data._get_agg_axis(axis)
else:
if numeric_only:
if filter_type is None or filter_type == "numeric":
data = self._get_numeric_data()
elif filter_type == "bool":
# GH 25101, # GH 24434
data = self._get_bool_data() if axis == 0 else self
else: # pragma: no cover
msg = (
"Generating numeric_only data with filter_type {f}"
"not supported.".format(f=filter_type)
)
raise NotImplementedError(msg)
values = data.values
labels = data._get_agg_axis(axis)
else:
values = self.values
result = f(values)
if hasattr(result, "dtype") and is_object_dtype(result.dtype):
try:
if filter_type is None or filter_type == "numeric":
result = result.astype(np.float64)
elif filter_type == "bool" and notna(result).all():
result = result.astype(np.bool_)
except (ValueError, TypeError):
# try to coerce to the original dtypes item by item if we can
if axis == 0:
result = coerce_to_dtypes(result, self.dtypes)
if constructor is not None:
result = Series(result, index=labels)
return result
def nunique(self, axis=0, dropna=True):
"""
Count distinct observations over requested axis.
Return Series with number of distinct observations. Can ignore NaN
values.
.. versionadded:: 0.20.0
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to use. 0 or 'index' for row-wise, 1 or 'columns' for
column-wise.
dropna : bool, default True
Don't include NaN in the counts.
Returns
-------
Series
See Also
--------
Series.nunique: Method nunique for Series.
DataFrame.count: Count non-NA cells for each column or row.
Examples
--------
>>> df = pd.DataFrame({'A': [1, 2, 3], 'B': [1, 1, 1]})
>>> df.nunique()
A 3
B 1
dtype: int64
>>> df.nunique(axis=1)
0 1
1 2
2 2
dtype: int64
"""
return self.apply(Series.nunique, axis=axis, dropna=dropna)
def idxmin(self, axis=0, skipna=True):
"""
Return index of first occurrence of minimum over requested axis.
NA/null values are excluded.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
0 or 'index' for row-wise, 1 or 'columns' for column-wise
skipna : boolean, default True
Exclude NA/null values. If an entire row/column is NA, the result
will be NA.
Returns
-------
Series
Indexes of minima along the specified axis.
Raises
------
ValueError
* If the row/column is empty
See Also
--------
Series.idxmin
Notes
-----
This method is the DataFrame version of ``ndarray.argmin``.
"""
axis = self._get_axis_number(axis)
indices = nanops.nanargmin(self.values, axis=axis, skipna=skipna)
index = self._get_axis(axis)
result = [index[i] if i >= 0 else np.nan for i in indices]
return Series(result, index=self._get_agg_axis(axis))
def idxmax(self, axis=0, skipna=True):
"""
Return index of first occurrence of maximum over requested axis.
NA/null values are excluded.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
0 or 'index' for row-wise, 1 or 'columns' for column-wise
skipna : boolean, default True
Exclude NA/null values. If an entire row/column is NA, the result
will be NA.
Returns
-------
Series
Indexes of maxima along the specified axis.
Raises
------
ValueError
* If the row/column is empty
See Also
--------
Series.idxmax
Notes
-----
This method is the DataFrame version of ``ndarray.argmax``.
"""
axis = self._get_axis_number(axis)
indices = nanops.nanargmax(self.values, axis=axis, skipna=skipna)
index = self._get_axis(axis)
result = [index[i] if i >= 0 else np.nan for i in indices]
return Series(result, index=self._get_agg_axis(axis))
def _get_agg_axis(self, axis_num):
"""
Let's be explicit about this.
"""
if axis_num == 0:
return self.columns
elif axis_num == 1:
return self.index
else:
raise ValueError("Axis must be 0 or 1 (got %r)" % axis_num)
def mode(self, axis=0, numeric_only=False, dropna=True):
"""
Get the mode(s) of each element along the selected axis.
The mode of a set of values is the value that appears most often.
It can be multiple values.
Parameters
----------
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to iterate over while searching for the mode:
* 0 or 'index' : get mode of each column
* 1 or 'columns' : get mode of each row
numeric_only : bool, default False
If True, only apply to numeric columns.
dropna : bool, default True
Don't consider counts of NaN/NaT.
.. versionadded:: 0.24.0
Returns
-------
DataFrame
The modes of each column or row.
See Also
--------
Series.mode : Return the highest frequency value in a Series.
Series.value_counts : Return the counts of values in a Series.
Examples
--------
>>> df = pd.DataFrame([('bird', 2, 2),
... ('mammal', 4, np.nan),
... ('arthropod', 8, 0),
... ('bird', 2, np.nan)],
... index=('falcon', 'horse', 'spider', 'ostrich'),
... columns=('species', 'legs', 'wings'))
>>> df
species legs wings
falcon bird 2 2.0
horse mammal 4 NaN
spider arthropod 8 0.0
ostrich bird 2 NaN
By default, missing values are not considered, and the mode of wings
are both 0 and 2. The second row of species and legs contains ``NaN``,
because they have only one mode, but the DataFrame has two rows.
>>> df.mode()
species legs wings
0 bird 2.0 0.0
1 NaN NaN 2.0
Setting ``dropna=False`` ``NaN`` values are considered and they can be
the mode (like for wings).
>>> df.mode(dropna=False)
species legs wings
0 bird 2 NaN
Setting ``numeric_only=True``, only the mode of numeric columns is
computed, and columns of other types are ignored.
>>> df.mode(numeric_only=True)
legs wings
0 2.0 0.0
1 NaN 2.0
To compute the mode over columns and not rows, use the axis parameter:
>>> df.mode(axis='columns', numeric_only=True)
0 1
falcon 2.0 NaN
horse 4.0 NaN
spider 0.0 8.0
ostrich 2.0 NaN
"""
data = self if not numeric_only else self._get_numeric_data()
def f(s):
return s.mode(dropna=dropna)
return data.apply(f, axis=axis)
def quantile(self, q=0.5, axis=0, numeric_only=True, interpolation="linear"):
"""
Return values at the given quantile over requested axis.
Parameters
----------
q : float or array-like, default 0.5 (50% quantile)
Value between 0 <= q <= 1, the quantile(s) to compute.
axis : {0, 1, 'index', 'columns'} (default 0)
Equals 0 or 'index' for row-wise, 1 or 'columns' for column-wise.
numeric_only : bool, default True
If False, the quantile of datetime and timedelta data will be
computed as well.
interpolation : {'linear', 'lower', 'higher', 'midpoint', 'nearest'}
This optional parameter specifies the interpolation method to use,
when the desired quantile lies between two data points `i` and `j`:
* linear: `i + (j - i) * fraction`, where `fraction` is the
fractional part of the index surrounded by `i` and `j`.
* lower: `i`.
* higher: `j`.
* nearest: `i` or `j` whichever is nearest.
* midpoint: (`i` + `j`) / 2.
Returns
-------
Series or DataFrame
If ``q`` is an array, a DataFrame will be returned where the
index is ``q``, the columns are the columns of self, and the
values are the quantiles.
If ``q`` is a float, a Series will be returned where the
index is the columns of self and the values are the quantiles.
See Also
--------
core.window.Rolling.quantile: Rolling quantile.
numpy.percentile: Numpy function to compute the percentile.
Examples
--------
>>> df = pd.DataFrame(np.array([[1, 1], [2, 10], [3, 100], [4, 100]]),
... columns=['a', 'b'])
>>> df.quantile(.1)
a 1.3
b 3.7
Name: 0.1, dtype: float64
>>> df.quantile([.1, .5])
a b
0.1 1.3 3.7
0.5 2.5 55.0
Specifying `numeric_only=False` will also compute the quantile of
datetime and timedelta data.
>>> df = pd.DataFrame({'A': [1, 2],
... 'B': [pd.Timestamp('2010'),
... pd.Timestamp('2011')],
... 'C': [pd.Timedelta('1 days'),
... pd.Timedelta('2 days')]})
>>> df.quantile(0.5, numeric_only=False)
A 1.5
B 2010-07-02 12:00:00
C 1 days 12:00:00
Name: 0.5, dtype: object
"""
self._check_percentile(q)
data = self._get_numeric_data() if numeric_only else self
axis = self._get_axis_number(axis)
is_transposed = axis == 1
if is_transposed:
data = data.T
if len(data.columns) == 0:
# GH#23925 _get_numeric_data may have dropped all columns
cols = Index([], name=self.columns.name)
if is_list_like(q):
return self._constructor([], index=q, columns=cols)
return self._constructor_sliced([], index=cols, name=q)
result = data._data.quantile(
qs=q, axis=1, interpolation=interpolation, transposed=is_transposed
)
if result.ndim == 2:
result = self._constructor(result)
else:
result = self._constructor_sliced(result, name=q)
if is_transposed:
result = result.T
return result
def to_timestamp(self, freq=None, how="start", axis=0, copy=True):
"""
Cast to DatetimeIndex of timestamps, at *beginning* of period.
Parameters
----------
freq : str, default frequency of PeriodIndex
Desired frequency.
how : {'s', 'e', 'start', 'end'}
Convention for converting period to timestamp; start of period
vs. end.
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to convert (the index by default).
copy : bool, default True
If False then underlying input data is not copied.
Returns
-------
DataFrame with DatetimeIndex
"""
new_data = self._data
if copy:
new_data = new_data.copy()
axis = self._get_axis_number(axis)
if axis == 0:
new_data.set_axis(1, self.index.to_timestamp(freq=freq, how=how))
elif axis == 1:
new_data.set_axis(0, self.columns.to_timestamp(freq=freq, how=how))
else: # pragma: no cover
raise AssertionError("Axis must be 0 or 1. Got {ax!s}".format(ax=axis))
return self._constructor(new_data)
def to_period(self, freq=None, axis=0, copy=True):
"""
Convert DataFrame from DatetimeIndex to PeriodIndex with desired
frequency (inferred from index if not passed).
Parameters
----------
freq : str, default
Frequency of the PeriodIndex.
axis : {0 or 'index', 1 or 'columns'}, default 0
The axis to convert (the index by default).
copy : bool, default True
If False then underlying input data is not copied.
Returns
-------
TimeSeries with PeriodIndex
"""
new_data = self._data
if copy:
new_data = new_data.copy()
axis = self._get_axis_number(axis)
if axis == 0:
new_data.set_axis(1, self.index.to_period(freq=freq))
elif axis == 1:
new_data.set_axis(0, self.columns.to_period(freq=freq))
else: # pragma: no cover
raise AssertionError("Axis must be 0 or 1. Got {ax!s}".format(ax=axis))
return self._constructor(new_data)
def isin(self, values):
"""
Whether each element in the DataFrame is contained in values.
Parameters
----------
values : iterable, Series, DataFrame or dict
The result will only be true at a location if all the
labels match. If `values` is a Series, that's the index. If
`values` is a dict, the keys must be the column names,
which must match. If `values` is a DataFrame,
then both the index and column labels must match.
Returns
-------
DataFrame
DataFrame of booleans showing whether each element in the DataFrame
is contained in values.
See Also
--------
DataFrame.eq: Equality test for DataFrame.
Series.isin: Equivalent method on Series.
Series.str.contains: Test if pattern or regex is contained within a
string of a Series or Index.
Examples
--------
>>> df = pd.DataFrame({'num_legs': [2, 4], 'num_wings': [2, 0]},
... index=['falcon', 'dog'])
>>> df
num_legs num_wings
falcon 2 2
dog 4 0
When ``values`` is a list check whether every value in the DataFrame
is present in the list (which animals have 0 or 2 legs or wings)
>>> df.isin([0, 2])
num_legs num_wings
falcon True True
dog False True
When ``values`` is a dict, we can pass values to check for each
column separately:
>>> df.isin({'num_wings': [0, 3]})
num_legs num_wings
falcon False False
dog False True
When ``values`` is a Series or DataFrame the index and column must
match. Note that 'falcon' does not match based on the number of legs
in df2.
>>> other = pd.DataFrame({'num_legs': [8, 2], 'num_wings': [0, 2]},
... index=['spider', 'falcon'])
>>> df.isin(other)
num_legs num_wings
falcon True True
dog False False
"""
if isinstance(values, dict):
from pandas.core.reshape.concat import concat
values = collections.defaultdict(list, values)
return concat(
(
self.iloc[:, [i]].isin(values[col])
for i, col in enumerate(self.columns)
),
axis=1,
)
elif isinstance(values, Series):
if not values.index.is_unique:
raise ValueError("cannot compute isin with " "a duplicate axis.")
return self.eq(values.reindex_like(self), axis="index")
elif isinstance(values, DataFrame):
if not (values.columns.is_unique and values.index.is_unique):
raise ValueError("cannot compute isin with " "a duplicate axis.")
return self.eq(values.reindex_like(self))
else:
if not is_list_like(values):
raise TypeError(
"only list-like or dict-like objects are "
"allowed to be passed to DataFrame.isin(), "
"you passed a "
"{0!r}".format(type(values).__name__)
)
return DataFrame(
algorithms.isin(self.values.ravel(), values).reshape(self.shape),
self.index,
self.columns,
)
# ----------------------------------------------------------------------
# Add plotting methods to DataFrame
plot = CachedAccessor("plot", pandas.plotting.PlotAccessor)
hist = pandas.plotting.hist_frame
boxplot = pandas.plotting.boxplot_frame
sparse = CachedAccessor("sparse", SparseFrameAccessor)
DataFrame._setup_axes(
["index", "columns"],
info_axis=1,
stat_axis=0,
axes_are_reversed=True,
aliases={"rows": 0},
docs={
"index": "The index (row labels) of the DataFrame.",
"columns": "The column labels of the DataFrame.",
},
)
DataFrame._add_numeric_operations()
DataFrame._add_series_or_dataframe_operations()
ops.add_flex_arithmetic_methods(DataFrame)
ops.add_special_arithmetic_methods(DataFrame)
def _from_nested_dict(data):
# TODO: this should be seriously cythonized
new_data = OrderedDict()
for index, s in data.items():
for col, v in s.items():
new_data[col] = new_data.get(col, OrderedDict())
new_data[col][index] = v
return new_data
def _put_str(s, space):
return "{s}".format(s=s)[:space].ljust(space)
| BugsInPy/BugsInPy/temp/projects/pandas/bug-169-fixed/pandas/pandas/core/frame.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-169-buggy/pandas/pandas/core/frame.py |
pandas-bug-21 | """
Data structure for 1-dimensional cross-sectional and time series data
"""
from io import StringIO
from shutil import get_terminal_size
from textwrap import dedent
from typing import (
IO,
TYPE_CHECKING,
Any,
Callable,
Iterable,
List,
Optional,
Tuple,
Type,
Union,
)
import warnings
import numpy as np
from pandas._config import get_option
from pandas._libs import lib, properties, reshape, tslibs
from pandas._typing import ArrayLike, Axis, DtypeObj, Label
from pandas.compat.numpy import function as nv
from pandas.util._decorators import Appender, Substitution, doc
from pandas.util._validators import validate_bool_kwarg, validate_percentile
from pandas.core.dtypes.cast import (
convert_dtypes,
maybe_cast_to_extension_array,
validate_numeric_casting,
)
from pandas.core.dtypes.common import (
ensure_platform_int,
is_bool,
is_categorical_dtype,
is_dict_like,
is_extension_array_dtype,
is_integer,
is_iterator,
is_list_like,
is_object_dtype,
is_scalar,
)
from pandas.core.dtypes.generic import (
ABCDataFrame,
ABCDatetimeIndex,
ABCMultiIndex,
ABCPeriodIndex,
ABCSeries,
)
from pandas.core.dtypes.inference import is_hashable
from pandas.core.dtypes.missing import (
isna,
na_value_for_dtype,
notna,
remove_na_arraylike,
)
import pandas as pd
from pandas.core import algorithms, base, generic, nanops, ops
from pandas.core.accessor import CachedAccessor
from pandas.core.arrays import ExtensionArray
from pandas.core.arrays.categorical import CategoricalAccessor
from pandas.core.arrays.sparse import SparseAccessor
import pandas.core.common as com
from pandas.core.construction import (
create_series_with_explicit_dtype,
extract_array,
is_empty_data,
sanitize_array,
)
from pandas.core.generic import NDFrame
from pandas.core.indexers import unpack_1tuple
from pandas.core.indexes.accessors import CombinedDatetimelikeProperties
from pandas.core.indexes.api import (
Float64Index,
Index,
InvalidIndexError,
MultiIndex,
ensure_index,
)
import pandas.core.indexes.base as ibase
from pandas.core.indexes.datetimes import DatetimeIndex
from pandas.core.indexes.period import PeriodIndex
from pandas.core.indexes.timedeltas import TimedeltaIndex
from pandas.core.indexing import check_bool_indexer
from pandas.core.internals import SingleBlockManager
from pandas.core.strings import StringMethods
from pandas.core.tools.datetimes import to_datetime
import pandas.io.formats.format as fmt
import pandas.plotting
if TYPE_CHECKING:
from pandas.core.frame import DataFrame
from pandas.core.groupby.generic import SeriesGroupBy
__all__ = ["Series"]
_shared_doc_kwargs = dict(
axes="index",
klass="Series",
axes_single_arg="{0 or 'index'}",
axis="""axis : {0 or 'index'}
Parameter needed for compatibility with DataFrame.""",
inplace="""inplace : boolean, default False
If True, performs operation inplace and returns None.""",
unique="np.ndarray",
duplicated="Series",
optional_by="",
optional_mapper="",
optional_labels="",
optional_axis="",
versionadded_to_excel="\n .. versionadded:: 0.20.0\n",
)
def _coerce_method(converter):
"""
Install the scalar coercion methods.
"""
def wrapper(self):
if len(self) == 1:
return converter(self.iloc[0])
raise TypeError(f"cannot convert the series to {converter}")
wrapper.__name__ = f"__{converter.__name__}__"
return wrapper
# ----------------------------------------------------------------------
# Series class
class Series(base.IndexOpsMixin, generic.NDFrame):
"""
One-dimensional ndarray with axis labels (including time series).
Labels need not be unique but must be a hashable type. The object
supports both integer- and label-based indexing and provides a host of
methods for performing operations involving the index. Statistical
methods from ndarray have been overridden to automatically exclude
missing data (currently represented as NaN).
Operations between Series (+, -, /, *, **) align values based on their
associated index values-- they need not be the same length. The result
index will be the sorted union of the two indexes.
Parameters
----------
data : array-like, Iterable, dict, or scalar value
Contains data stored in Series.
.. versionchanged:: 0.23.0
If data is a dict, argument order is maintained for Python 3.6
and later.
index : array-like or Index (1d)
Values must be hashable and have the same length as `data`.
Non-unique index values are allowed. Will default to
RangeIndex (0, 1, 2, ..., n) if not provided. If both a dict and index
sequence are used, the index will override the keys found in the
dict.
dtype : str, numpy.dtype, or ExtensionDtype, optional
Data type for the output Series. If not specified, this will be
inferred from `data`.
See the :ref:`user guide <basics.dtypes>` for more usages.
name : str, optional
The name to give to the Series.
copy : bool, default False
Copy input data.
"""
_typ = "series"
_name: Label
_metadata: List[str] = ["name"]
_internal_names_set = {"index"} | generic.NDFrame._internal_names_set
_accessors = {"dt", "cat", "str", "sparse"}
_deprecations = (
base.IndexOpsMixin._deprecations
| generic.NDFrame._deprecations
| frozenset(["compress", "ptp"])
)
# Override cache_readonly bc Series is mutable
hasnans = property(
base.IndexOpsMixin.hasnans.func, doc=base.IndexOpsMixin.hasnans.__doc__
)
_mgr: SingleBlockManager
div: Callable[["Series", Any], "Series"]
rdiv: Callable[["Series", Any], "Series"]
# ----------------------------------------------------------------------
# Constructors
def __init__(
self, data=None, index=None, dtype=None, name=None, copy=False, fastpath=False
):
if (
isinstance(data, SingleBlockManager)
and index is None
and dtype is None
and copy is False
):
# GH#33357 called with just the SingleBlockManager
NDFrame.__init__(self, data)
self.name = name
return
# we are called internally, so short-circuit
if fastpath:
# data is an ndarray, index is defined
if not isinstance(data, SingleBlockManager):
data = SingleBlockManager.from_array(data, index)
if copy:
data = data.copy()
if index is None:
index = data.index
else:
name = ibase.maybe_extract_name(name, data, type(self))
if is_empty_data(data) and dtype is None:
# gh-17261
warnings.warn(
"The default dtype for empty Series will be 'object' instead "
"of 'float64' in a future version. Specify a dtype explicitly "
"to silence this warning.",
DeprecationWarning,
stacklevel=2,
)
# uncomment the line below when removing the DeprecationWarning
# dtype = np.dtype(object)
if index is not None:
index = ensure_index(index)
if data is None:
data = {}
if dtype is not None:
dtype = self._validate_dtype(dtype)
if isinstance(data, MultiIndex):
raise NotImplementedError(
"initializing a Series from a MultiIndex is not supported"
)
elif isinstance(data, Index):
if dtype is not None:
# astype copies
data = data.astype(dtype)
else:
# need to copy to avoid aliasing issues
data = data._values.copy()
if isinstance(data, ABCDatetimeIndex) and data.tz is not None:
# GH#24096 need copy to be deep for datetime64tz case
# TODO: See if we can avoid these copies
data = data._values.copy(deep=True)
copy = False
elif isinstance(data, np.ndarray):
if len(data.dtype):
# GH#13296 we are dealing with a compound dtype, which
# should be treated as 2D
raise ValueError(
"Cannot construct a Series from an ndarray with "
"compound dtype. Use DataFrame instead."
)
pass
elif isinstance(data, ABCSeries):
if index is None:
index = data.index
else:
data = data.reindex(index, copy=copy)
data = data._mgr
elif is_dict_like(data):
data, index = self._init_dict(data, index, dtype)
dtype = None
copy = False
elif isinstance(data, SingleBlockManager):
if index is None:
index = data.index
elif not data.index.equals(index) or copy:
# GH#19275 SingleBlockManager input should only be called
# internally
raise AssertionError(
"Cannot pass both SingleBlockManager "
"`data` argument and a different "
"`index` argument. `copy` must be False."
)
elif is_extension_array_dtype(data):
pass
elif isinstance(data, (set, frozenset)):
raise TypeError(f"'{type(data).__name__}' type is unordered")
else:
data = com.maybe_iterable_to_list(data)
if index is None:
if not is_list_like(data):
data = [data]
index = ibase.default_index(len(data))
elif is_list_like(data):
# a scalar numpy array is list-like but doesn't
# have a proper length
try:
if len(index) != len(data):
raise ValueError(
f"Length of passed values is {len(data)}, "
f"index implies {len(index)}."
)
except TypeError:
pass
# create/copy the manager
if isinstance(data, SingleBlockManager):
if dtype is not None:
data = data.astype(dtype=dtype, errors="ignore", copy=copy)
elif copy:
data = data.copy()
else:
data = sanitize_array(data, index, dtype, copy, raise_cast_failure=True)
data = SingleBlockManager.from_array(data, index)
generic.NDFrame.__init__(self, data)
self.name = name
self._set_axis(0, index, fastpath=True)
def _init_dict(self, data, index=None, dtype=None):
"""
Derive the "_mgr" and "index" attributes of a new Series from a
dictionary input.
Parameters
----------
data : dict or dict-like
Data used to populate the new Series.
index : Index or index-like, default None
Index for the new Series: if None, use dict keys.
dtype : dtype, default None
The dtype for the new Series: if None, infer from data.
Returns
-------
_data : BlockManager for the new Series
index : index for the new Series
"""
# Looking for NaN in dict doesn't work ({np.nan : 1}[float('nan')]
# raises KeyError), so we iterate the entire dict, and align
if data:
keys, values = zip(*data.items())
values = list(values)
elif index is not None:
# fastpath for Series(data=None). Just use broadcasting a scalar
# instead of reindexing.
values = na_value_for_dtype(dtype)
keys = index
else:
keys, values = [], []
# Input is now list-like, so rely on "standard" construction:
# TODO: passing np.float64 to not break anything yet. See GH-17261
s = create_series_with_explicit_dtype(
values, index=keys, dtype=dtype, dtype_if_empty=np.float64
)
# Now we just make sure the order is respected, if any
if data and index is not None:
s = s.reindex(index, copy=False)
return s._mgr, s.index
# ----------------------------------------------------------------------
@property
def _constructor(self) -> Type["Series"]:
return Series
@property
def _constructor_expanddim(self) -> Type["DataFrame"]:
from pandas.core.frame import DataFrame
return DataFrame
# types
@property
def _can_hold_na(self):
return self._mgr._can_hold_na
_index = None
def _set_axis(self, axis: int, labels, fastpath: bool = False) -> None:
"""
Override generic, we want to set the _typ here.
This is called from the cython code when we set the `index` attribute
directly, e.g. `series.index = [1, 2, 3]`.
"""
if not fastpath:
labels = ensure_index(labels)
is_all_dates = labels.is_all_dates
if is_all_dates:
if not isinstance(labels, (DatetimeIndex, PeriodIndex, TimedeltaIndex)):
try:
labels = DatetimeIndex(labels)
# need to set here because we changed the index
if fastpath:
self._mgr.set_axis(axis, labels)
except (tslibs.OutOfBoundsDatetime, ValueError):
# labels may exceeds datetime bounds,
# or not be a DatetimeIndex
pass
object.__setattr__(self, "_index", labels)
if not fastpath:
# The ensure_index call above ensures we have an Index object
self._mgr.set_axis(axis, labels)
# ndarray compatibility
@property
def dtype(self) -> DtypeObj:
"""
Return the dtype object of the underlying data.
"""
return self._mgr.dtype
@property
def dtypes(self) -> DtypeObj:
"""
Return the dtype object of the underlying data.
"""
# DataFrame compatibility
return self.dtype
@property
def name(self) -> Label:
"""
Return the name of the Series.
The name of a Series becomes its index or column name if it is used
to form a DataFrame. It is also used whenever displaying the Series
using the interpreter.
Returns
-------
label (hashable object)
The name of the Series, also the column name if part of a DataFrame.
See Also
--------
Series.rename : Sets the Series name when given a scalar input.
Index.name : Corresponding Index property.
Examples
--------
The Series name can be set initially when calling the constructor.
>>> s = pd.Series([1, 2, 3], dtype=np.int64, name='Numbers')
>>> s
0 1
1 2
2 3
Name: Numbers, dtype: int64
>>> s.name = "Integers"
>>> s
0 1
1 2
2 3
Name: Integers, dtype: int64
The name of a Series within a DataFrame is its column name.
>>> df = pd.DataFrame([[1, 2], [3, 4], [5, 6]],
... columns=["Odd Numbers", "Even Numbers"])
>>> df
Odd Numbers Even Numbers
0 1 2
1 3 4
2 5 6
>>> df["Even Numbers"].name
'Even Numbers'
"""
return self._name
@name.setter
def name(self, value: Label) -> None:
if not is_hashable(value):
raise TypeError("Series.name must be a hashable type")
object.__setattr__(self, "_name", value)
@property
def values(self):
"""
Return Series as ndarray or ndarray-like depending on the dtype.
.. warning::
We recommend using :attr:`Series.array` or
:meth:`Series.to_numpy`, depending on whether you need
a reference to the underlying data or a NumPy array.
Returns
-------
numpy.ndarray or ndarray-like
See Also
--------
Series.array : Reference to the underlying data.
Series.to_numpy : A NumPy array representing the underlying data.
Examples
--------
>>> pd.Series([1, 2, 3]).values
array([1, 2, 3])
>>> pd.Series(list('aabc')).values
array(['a', 'a', 'b', 'c'], dtype=object)
>>> pd.Series(list('aabc')).astype('category').values
[a, a, b, c]
Categories (3, object): [a, b, c]
Timezone aware datetime data is converted to UTC:
>>> pd.Series(pd.date_range('20130101', periods=3,
... tz='US/Eastern')).values
array(['2013-01-01T05:00:00.000000000',
'2013-01-02T05:00:00.000000000',
'2013-01-03T05:00:00.000000000'], dtype='datetime64[ns]')
"""
return self._mgr.external_values()
@property
def _values(self):
"""
Return the internal repr of this data (defined by Block.interval_values).
This are the values as stored in the Block (ndarray or ExtensionArray
depending on the Block class), with datetime64[ns] and timedelta64[ns]
wrapped in ExtensionArrays to match Index._values behavior.
Differs from the public ``.values`` for certain data types, because of
historical backwards compatibility of the public attribute (e.g. period
returns object ndarray and datetimetz a datetime64[ns] ndarray for
``.values`` while it returns an ExtensionArray for ``._values`` in those
cases).
Differs from ``.array`` in that this still returns the numpy array if
the Block is backed by a numpy array (except for datetime64 and
timedelta64 dtypes), while ``.array`` ensures to always return an
ExtensionArray.
Overview:
dtype | values | _values | array |
----------- | ------------- | ------------- | ------------- |
Numeric | ndarray | ndarray | PandasArray |
Category | Categorical | Categorical | Categorical |
dt64[ns] | ndarray[M8ns] | DatetimeArray | DatetimeArray |
dt64[ns tz] | ndarray[M8ns] | DatetimeArray | DatetimeArray |
td64[ns] | ndarray[m8ns] | TimedeltaArray| ndarray[m8ns] |
Period | ndarray[obj] | PeriodArray | PeriodArray |
Nullable | EA | EA | EA |
"""
return self._mgr.internal_values()
@Appender(base.IndexOpsMixin.array.__doc__) # type: ignore
@property
def array(self) -> ExtensionArray:
return self._mgr._block.array_values()
# ops
def ravel(self, order="C"):
"""
Return the flattened underlying data as an ndarray.
Returns
-------
numpy.ndarray or ndarray-like
Flattened data of the Series.
See Also
--------
numpy.ndarray.ravel : Return a flattened array.
"""
return self._values.ravel(order=order)
def __len__(self) -> int:
"""
Return the length of the Series.
"""
return len(self._mgr)
def view(self, dtype=None) -> "Series":
"""
Create a new view of the Series.
This function will return a new Series with a view of the same
underlying values in memory, optionally reinterpreted with a new data
type. The new data type must preserve the same size in bytes as to not
cause index misalignment.
Parameters
----------
dtype : data type
Data type object or one of their string representations.
Returns
-------
Series
A new Series object as a view of the same data in memory.
See Also
--------
numpy.ndarray.view : Equivalent numpy function to create a new view of
the same data in memory.
Notes
-----
Series are instantiated with ``dtype=float64`` by default. While
``numpy.ndarray.view()`` will return a view with the same data type as
the original array, ``Series.view()`` (without specified dtype)
will try using ``float64`` and may fail if the original data type size
in bytes is not the same.
Examples
--------
>>> s = pd.Series([-2, -1, 0, 1, 2], dtype='int8')
>>> s
0 -2
1 -1
2 0
3 1
4 2
dtype: int8
The 8 bit signed integer representation of `-1` is `0b11111111`, but
the same bytes represent 255 if read as an 8 bit unsigned integer:
>>> us = s.view('uint8')
>>> us
0 254
1 255
2 0
3 1
4 2
dtype: uint8
The views share the same underlying values:
>>> us[0] = 128
>>> s
0 -128
1 -1
2 0
3 1
4 2
dtype: int8
"""
return self._constructor(
self._values.view(dtype), index=self.index
).__finalize__(self, method="view")
# ----------------------------------------------------------------------
# NDArray Compat
_HANDLED_TYPES = (Index, ExtensionArray, np.ndarray)
def __array_ufunc__(
self, ufunc: Callable, method: str, *inputs: Any, **kwargs: Any
):
# TODO: handle DataFrame
cls = type(self)
# for binary ops, use our custom dunder methods
result = ops.maybe_dispatch_ufunc_to_dunder_op(
self, ufunc, method, *inputs, **kwargs
)
if result is not NotImplemented:
return result
# Determine if we should defer.
no_defer = (np.ndarray.__array_ufunc__, cls.__array_ufunc__)
for item in inputs:
higher_priority = (
hasattr(item, "__array_priority__")
and item.__array_priority__ > self.__array_priority__
)
has_array_ufunc = (
hasattr(item, "__array_ufunc__")
and type(item).__array_ufunc__ not in no_defer
and not isinstance(item, self._HANDLED_TYPES)
)
if higher_priority or has_array_ufunc:
return NotImplemented
# align all the inputs.
names = [getattr(x, "name") for x in inputs if hasattr(x, "name")]
types = tuple(type(x) for x in inputs)
# TODO: dataframe
alignable = [x for x, t in zip(inputs, types) if issubclass(t, Series)]
if len(alignable) > 1:
# This triggers alignment.
# At the moment, there aren't any ufuncs with more than two inputs
# so this ends up just being x1.index | x2.index, but we write
# it to handle *args.
index = alignable[0].index
for s in alignable[1:]:
index |= s.index
inputs = tuple(
x.reindex(index) if issubclass(t, Series) else x
for x, t in zip(inputs, types)
)
else:
index = self.index
inputs = tuple(extract_array(x, extract_numpy=True) for x in inputs)
result = getattr(ufunc, method)(*inputs, **kwargs)
name = names[0] if len(set(names)) == 1 else None
def construct_return(result):
if lib.is_scalar(result):
return result
elif result.ndim > 1:
# e.g. np.subtract.outer
if method == "outer":
# GH#27198
raise NotImplementedError
return result
return self._constructor(result, index=index, name=name, copy=False)
if type(result) is tuple:
# multiple return values
return tuple(construct_return(x) for x in result)
elif method == "at":
# no return value
return None
else:
return construct_return(result)
def __array__(self, dtype=None) -> np.ndarray:
"""
Return the values as a NumPy array.
Users should not call this directly. Rather, it is invoked by
:func:`numpy.array` and :func:`numpy.asarray`.
Parameters
----------
dtype : str or numpy.dtype, optional
The dtype to use for the resulting NumPy array. By default,
the dtype is inferred from the data.
Returns
-------
numpy.ndarray
The values in the series converted to a :class:`numpy.ndarray`
with the specified `dtype`.
See Also
--------
array : Create a new array from data.
Series.array : Zero-copy view to the array backing the Series.
Series.to_numpy : Series method for similar behavior.
Examples
--------
>>> ser = pd.Series([1, 2, 3])
>>> np.asarray(ser)
array([1, 2, 3])
For timezone-aware data, the timezones may be retained with
``dtype='object'``
>>> tzser = pd.Series(pd.date_range('2000', periods=2, tz="CET"))
>>> np.asarray(tzser, dtype="object")
array([Timestamp('2000-01-01 00:00:00+0100', tz='CET', freq='D'),
Timestamp('2000-01-02 00:00:00+0100', tz='CET', freq='D')],
dtype=object)
Or the values may be localized to UTC and the tzinfo discarded with
``dtype='datetime64[ns]'``
>>> np.asarray(tzser, dtype="datetime64[ns]") # doctest: +ELLIPSIS
array(['1999-12-31T23:00:00.000000000', ...],
dtype='datetime64[ns]')
"""
return np.asarray(self.array, dtype)
# ----------------------------------------------------------------------
# Unary Methods
# coercion
__float__ = _coerce_method(float)
__long__ = _coerce_method(int)
__int__ = _coerce_method(int)
# ----------------------------------------------------------------------
# indexers
@property
def axes(self) -> List[Index]:
"""
Return a list of the row axis labels.
"""
return [self.index]
# ----------------------------------------------------------------------
# Indexing Methods
@Appender(generic.NDFrame.take.__doc__)
def take(self, indices, axis=0, is_copy=None, **kwargs) -> "Series":
if is_copy is not None:
warnings.warn(
"is_copy is deprecated and will be removed in a future version. "
"'take' always returns a copy, so there is no need to specify this.",
FutureWarning,
stacklevel=2,
)
nv.validate_take(tuple(), kwargs)
indices = ensure_platform_int(indices)
new_index = self.index.take(indices)
new_values = self._values.take(indices)
result = self._constructor(new_values, index=new_index, fastpath=True)
return result.__finalize__(self, method="take")
def _take_with_is_copy(self, indices, axis=0):
"""
Internal version of the `take` method that sets the `_is_copy`
attribute to keep track of the parent dataframe (using in indexing
for the SettingWithCopyWarning). For Series this does the same
as the public take (it never sets `_is_copy`).
See the docstring of `take` for full explanation of the parameters.
"""
return self.take(indices=indices, axis=axis)
def _ixs(self, i: int, axis: int = 0):
"""
Return the i-th value or values in the Series by location.
Parameters
----------
i : int
Returns
-------
scalar (int) or Series (slice, sequence)
"""
return self._values[i]
def _slice(self, slobj: slice, axis: int = 0) -> "Series":
# axis kwarg is retained for compat with NDFrame method
# _slice is *always* positional
return self._get_values(slobj)
def __getitem__(self, key):
key = com.apply_if_callable(key, self)
if key is Ellipsis:
return self
key_is_scalar = is_scalar(key)
if isinstance(key, (list, tuple)):
key = unpack_1tuple(key)
if is_integer(key) and self.index._should_fallback_to_positional():
return self._values[key]
elif key_is_scalar:
return self._get_value(key)
if (
isinstance(key, tuple)
and is_hashable(key)
and isinstance(self.index, MultiIndex)
):
# Otherwise index.get_value will raise InvalidIndexError
try:
result = self._get_value(key)
return result
except KeyError:
# We still have the corner case where this tuple is a key
# in the first level of our MultiIndex
return self._get_values_tuple(key)
if is_iterator(key):
key = list(key)
if com.is_bool_indexer(key):
key = check_bool_indexer(self.index, key)
key = np.asarray(key, dtype=bool)
return self._get_values(key)
return self._get_with(key)
def _get_with(self, key):
# other: fancy integer or otherwise
if isinstance(key, slice):
# _convert_slice_indexer to determin if this slice is positional
# or label based, and if the latter, convert to positional
slobj = self.index._convert_slice_indexer(key, kind="getitem")
return self._slice(slobj)
elif isinstance(key, ABCDataFrame):
raise TypeError(
"Indexing a Series with DataFrame is not "
"supported, use the appropriate DataFrame column"
)
elif isinstance(key, tuple):
return self._get_values_tuple(key)
elif not is_list_like(key):
# e.g. scalars that aren't recognized by lib.is_scalar, GH#32684
return self.loc[key]
if not isinstance(key, (list, np.ndarray, ExtensionArray, Series, Index)):
key = list(key)
if isinstance(key, Index):
key_type = key.inferred_type
else:
key_type = lib.infer_dtype(key, skipna=False)
# Note: The key_type == "boolean" case should be caught by the
# com.is_bool_indexer check in __getitem__
if key_type == "integer":
# We need to decide whether to treat this as a positional indexer
# (i.e. self.iloc) or label-based (i.e. self.loc)
if not self.index._should_fallback_to_positional():
return self.loc[key]
else:
return self.iloc[key]
if isinstance(key, list):
# handle the dup indexing case GH#4246
return self.loc[key]
return self.reindex(key)
def _get_values_tuple(self, key):
# mpl hackaround
if com.any_none(*key):
# suppress warning from slicing the index with a 2d indexer.
# eventually we'll want Series itself to warn.
with warnings.catch_warnings():
warnings.filterwarnings(
"ignore", "Support for multi-dim", DeprecationWarning
)
return self._get_values(key)
if not isinstance(self.index, MultiIndex):
raise ValueError("Can only tuple-index with a MultiIndex")
# If key is contained, would have returned by now
indexer, new_index = self.index.get_loc_level(key)
return self._constructor(self._values[indexer], index=new_index).__finalize__(
self,
)
def _get_values(self, indexer):
try:
return self._constructor(self._mgr.get_slice(indexer)).__finalize__(self,)
except ValueError:
# mpl compat if we look up e.g. ser[:, np.newaxis];
# see tests.series.timeseries.test_mpl_compat_hack
return self._values[indexer]
def _get_value(self, label, takeable: bool = False):
"""
Quickly retrieve single value at passed index label.
Parameters
----------
label : object
takeable : interpret the index as indexers, default False
Returns
-------
scalar value
"""
if takeable:
return self._values[label]
# Similar to Index.get_value, but we do not fall back to positional
loc = self.index.get_loc(label)
return self.index._get_values_for_loc(self, loc, label)
def __setitem__(self, key, value):
key = com.apply_if_callable(key, self)
cacher_needs_updating = self._check_is_chained_assignment_possible()
if key is Ellipsis:
key = slice(None)
try:
self._set_with_engine(key, value)
except (KeyError, ValueError):
values = self._values
if is_integer(key) and not self.index.inferred_type == "integer":
# positional setter
values[key] = value
else:
# GH#12862 adding an new key to the Series
self.loc[key] = value
except TypeError as e:
if isinstance(key, tuple) and not isinstance(self.index, MultiIndex):
raise ValueError("Can only tuple-index with a MultiIndex") from e
if com.is_bool_indexer(key):
key = check_bool_indexer(self.index, key)
key = np.asarray(key, dtype=bool)
try:
self._where(~key, value, inplace=True)
except InvalidIndexError:
self.iloc[key] = value
return
else:
self._set_with(key, value)
if cacher_needs_updating:
self._maybe_update_cacher()
def _set_with_engine(self, key, value):
# fails with AttributeError for IntervalIndex
loc = self.index._engine.get_loc(key)
validate_numeric_casting(self.dtype, value)
self._values[loc] = value
def _set_with(self, key, value):
# other: fancy integer or otherwise
if isinstance(key, slice):
# extract_array so that if we set e.g. ser[-5:] = ser[:5]
# we get the first five values, and not 5 NaNs
indexer = self.index._convert_slice_indexer(key, kind="getitem")
self.iloc[indexer] = extract_array(value, extract_numpy=True)
else:
assert not isinstance(key, tuple)
if is_scalar(key):
key = [key]
if isinstance(key, Index):
key_type = key.inferred_type
key = key._values
else:
key_type = lib.infer_dtype(key, skipna=False)
# Note: key_type == "boolean" should not occur because that
# should be caught by the is_bool_indexer check in __setitem__
if key_type == "integer":
if not self.index._should_fallback_to_positional():
self.loc[key] = value
else:
self.iloc[key] = value
else:
self.loc[key] = value
def _set_value(self, label, value, takeable: bool = False):
"""
Quickly set single value at passed label.
If label is not contained, a new object is created with the label
placed at the end of the result index.
Parameters
----------
label : object
Partial indexing with MultiIndex not allowed.
value : object
Scalar value.
takeable : interpret the index as indexers, default False
"""
try:
if takeable:
self._values[label] = value
else:
loc = self.index.get_loc(label)
validate_numeric_casting(self.dtype, value)
self._values[loc] = value
except KeyError:
# set using a non-recursive method
self.loc[label] = value
# ----------------------------------------------------------------------
# Unsorted
@property
def _is_mixed_type(self):
return False
def repeat(self, repeats, axis=None) -> "Series":
"""
Repeat elements of a Series.
Returns a new Series where each element of the current Series
is repeated consecutively a given number of times.
Parameters
----------
repeats : int or array of ints
The number of repetitions for each element. This should be a
non-negative integer. Repeating 0 times will return an empty
Series.
axis : None
Must be ``None``. Has no effect but is accepted for compatibility
with numpy.
Returns
-------
Series
Newly created Series with repeated elements.
See Also
--------
Index.repeat : Equivalent function for Index.
numpy.repeat : Similar method for :class:`numpy.ndarray`.
Examples
--------
>>> s = pd.Series(['a', 'b', 'c'])
>>> s
0 a
1 b
2 c
dtype: object
>>> s.repeat(2)
0 a
0 a
1 b
1 b
2 c
2 c
dtype: object
>>> s.repeat([1, 2, 3])
0 a
1 b
1 b
2 c
2 c
2 c
dtype: object
"""
nv.validate_repeat(tuple(), dict(axis=axis))
new_index = self.index.repeat(repeats)
new_values = self._values.repeat(repeats)
return self._constructor(new_values, index=new_index).__finalize__(
self, method="repeat"
)
def reset_index(self, level=None, drop=False, name=None, inplace=False):
"""
Generate a new DataFrame or Series with the index reset.
This is useful when the index needs to be treated as a column, or
when the index is meaningless and needs to be reset to the default
before another operation.
Parameters
----------
level : int, str, tuple, or list, default optional
For a Series with a MultiIndex, only remove the specified levels
from the index. Removes all levels by default.
drop : bool, default False
Just reset the index, without inserting it as a column in
the new DataFrame.
name : object, optional
The name to use for the column containing the original Series
values. Uses ``self.name`` by default. This argument is ignored
when `drop` is True.
inplace : bool, default False
Modify the Series in place (do not create a new object).
Returns
-------
Series or DataFrame
When `drop` is False (the default), a DataFrame is returned.
The newly created columns will come first in the DataFrame,
followed by the original Series values.
When `drop` is True, a `Series` is returned.
In either case, if ``inplace=True``, no value is returned.
See Also
--------
DataFrame.reset_index: Analogous function for DataFrame.
Examples
--------
>>> s = pd.Series([1, 2, 3, 4], name='foo',
... index=pd.Index(['a', 'b', 'c', 'd'], name='idx'))
Generate a DataFrame with default index.
>>> s.reset_index()
idx foo
0 a 1
1 b 2
2 c 3
3 d 4
To specify the name of the new column use `name`.
>>> s.reset_index(name='values')
idx values
0 a 1
1 b 2
2 c 3
3 d 4
To generate a new Series with the default set `drop` to True.
>>> s.reset_index(drop=True)
0 1
1 2
2 3
3 4
Name: foo, dtype: int64
To update the Series in place, without generating a new one
set `inplace` to True. Note that it also requires ``drop=True``.
>>> s.reset_index(inplace=True, drop=True)
>>> s
0 1
1 2
2 3
3 4
Name: foo, dtype: int64
The `level` parameter is interesting for Series with a multi-level
index.
>>> arrays = [np.array(['bar', 'bar', 'baz', 'baz']),
... np.array(['one', 'two', 'one', 'two'])]
>>> s2 = pd.Series(
... range(4), name='foo',
... index=pd.MultiIndex.from_arrays(arrays,
... names=['a', 'b']))
To remove a specific level from the Index, use `level`.
>>> s2.reset_index(level='a')
a foo
b
one bar 0
two bar 1
one baz 2
two baz 3
If `level` is not set, all levels are removed from the Index.
>>> s2.reset_index()
a b foo
0 bar one 0
1 bar two 1
2 baz one 2
3 baz two 3
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if drop:
new_index = ibase.default_index(len(self))
if level is not None:
if not isinstance(level, (tuple, list)):
level = [level]
level = [self.index._get_level_number(lev) for lev in level]
if len(level) < self.index.nlevels:
new_index = self.index.droplevel(level)
if inplace:
self.index = new_index
# set name if it was passed, otherwise, keep the previous name
self.name = name or self.name
else:
return self._constructor(
self._values.copy(), index=new_index
).__finalize__(self, method="reset_index")
elif inplace:
raise TypeError(
"Cannot reset_index inplace on a Series to create a DataFrame"
)
else:
df = self.to_frame(name)
return df.reset_index(level=level, drop=drop)
# ----------------------------------------------------------------------
# Rendering Methods
def __repr__(self) -> str:
"""
Return a string representation for a particular Series.
"""
buf = StringIO("")
width, height = get_terminal_size()
max_rows = (
height
if get_option("display.max_rows") == 0
else get_option("display.max_rows")
)
min_rows = (
height
if get_option("display.max_rows") == 0
else get_option("display.min_rows")
)
show_dimensions = get_option("display.show_dimensions")
self.to_string(
buf=buf,
name=self.name,
dtype=self.dtype,
min_rows=min_rows,
max_rows=max_rows,
length=show_dimensions,
)
result = buf.getvalue()
return result
def to_string(
self,
buf=None,
na_rep="NaN",
float_format=None,
header=True,
index=True,
length=False,
dtype=False,
name=False,
max_rows=None,
min_rows=None,
):
"""
Render a string representation of the Series.
Parameters
----------
buf : StringIO-like, optional
Buffer to write to.
na_rep : str, optional
String representation of NaN to use, default 'NaN'.
float_format : one-parameter function, optional
Formatter function to apply to columns' elements if they are
floats, default None.
header : bool, default True
Add the Series header (index name).
index : bool, optional
Add index (row) labels, default True.
length : bool, default False
Add the Series length.
dtype : bool, default False
Add the Series dtype.
name : bool, default False
Add the Series name if not None.
max_rows : int, optional
Maximum number of rows to show before truncating. If None, show
all.
min_rows : int, optional
The number of rows to display in a truncated repr (when number
of rows is above `max_rows`).
Returns
-------
str or None
String representation of Series if ``buf=None``, otherwise None.
"""
formatter = fmt.SeriesFormatter(
self,
name=name,
length=length,
header=header,
index=index,
dtype=dtype,
na_rep=na_rep,
float_format=float_format,
min_rows=min_rows,
max_rows=max_rows,
)
result = formatter.to_string()
# catch contract violations
if not isinstance(result, str):
raise AssertionError(
"result must be of type str, type "
f"of result is {repr(type(result).__name__)}"
)
if buf is None:
return result
else:
try:
buf.write(result)
except AttributeError:
with open(buf, "w") as f:
f.write(result)
@Appender(
"""
Examples
--------
>>> s = pd.Series(["elk", "pig", "dog", "quetzal"], name="animal")
>>> print(s.to_markdown())
| | animal |
|---:|:---------|
| 0 | elk |
| 1 | pig |
| 2 | dog |
| 3 | quetzal |
"""
)
@Substitution(klass="Series")
@Appender(generic._shared_docs["to_markdown"])
def to_markdown(
self, buf: Optional[IO[str]] = None, mode: Optional[str] = None, **kwargs
) -> Optional[str]:
return self.to_frame().to_markdown(buf, mode, **kwargs)
# ----------------------------------------------------------------------
def items(self) -> Iterable[Tuple[Label, Any]]:
"""
Lazily iterate over (index, value) tuples.
This method returns an iterable tuple (index, value). This is
convenient if you want to create a lazy iterator.
Returns
-------
iterable
Iterable of tuples containing the (index, value) pairs from a
Series.
See Also
--------
DataFrame.items : Iterate over (column name, Series) pairs.
DataFrame.iterrows : Iterate over DataFrame rows as (index, Series) pairs.
Examples
--------
>>> s = pd.Series(['A', 'B', 'C'])
>>> for index, value in s.items():
... print(f"Index : {index}, Value : {value}")
Index : 0, Value : A
Index : 1, Value : B
Index : 2, Value : C
"""
return zip(iter(self.index), iter(self))
@Appender(items.__doc__)
def iteritems(self) -> Iterable[Tuple[Label, Any]]:
return self.items()
# ----------------------------------------------------------------------
# Misc public methods
def keys(self) -> Index:
"""
Return alias for index.
Returns
-------
Index
Index of the Series.
"""
return self.index
def to_dict(self, into=dict):
"""
Convert Series to {label -> value} dict or dict-like object.
Parameters
----------
into : class, default dict
The collections.abc.Mapping subclass to use as the return
object. Can be the actual class or an empty
instance of the mapping type you want. If you want a
collections.defaultdict, you must pass it initialized.
Returns
-------
collections.abc.Mapping
Key-value representation of Series.
Examples
--------
>>> s = pd.Series([1, 2, 3, 4])
>>> s.to_dict()
{0: 1, 1: 2, 2: 3, 3: 4}
>>> from collections import OrderedDict, defaultdict
>>> s.to_dict(OrderedDict)
OrderedDict([(0, 1), (1, 2), (2, 3), (3, 4)])
>>> dd = defaultdict(list)
>>> s.to_dict(dd)
defaultdict(<class 'list'>, {0: 1, 1: 2, 2: 3, 3: 4})
"""
# GH16122
into_c = com.standardize_mapping(into)
return into_c(self.items())
def to_frame(self, name=None) -> "DataFrame":
"""
Convert Series to DataFrame.
Parameters
----------
name : object, default None
The passed name should substitute for the series name (if it has
one).
Returns
-------
DataFrame
DataFrame representation of Series.
Examples
--------
>>> s = pd.Series(["a", "b", "c"],
... name="vals")
>>> s.to_frame()
vals
0 a
1 b
2 c
"""
if name is None:
df = self._constructor_expanddim(self)
else:
df = self._constructor_expanddim({name: self})
return df
def _set_name(self, name, inplace=False) -> "Series":
"""
Set the Series name.
Parameters
----------
name : str
inplace : bool
Whether to modify `self` directly or return a copy.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
ser = self if inplace else self.copy()
ser.name = name
return ser
@Appender(
"""
Examples
--------
>>> ser = pd.Series([390., 350., 30., 20.],
... index=['Falcon', 'Falcon', 'Parrot', 'Parrot'], name="Max Speed")
>>> ser
Falcon 390.0
Falcon 350.0
Parrot 30.0
Parrot 20.0
Name: Max Speed, dtype: float64
>>> ser.groupby(["a", "b", "a", "b"]).mean()
a 210.0
b 185.0
Name: Max Speed, dtype: float64
>>> ser.groupby(level=0).mean()
Falcon 370.0
Parrot 25.0
Name: Max Speed, dtype: float64
>>> ser.groupby(ser > 100).mean()
Max Speed
False 25.0
True 370.0
Name: Max Speed, dtype: float64
**Grouping by Indexes**
We can groupby different levels of a hierarchical index
using the `level` parameter:
>>> arrays = [['Falcon', 'Falcon', 'Parrot', 'Parrot'],
... ['Captive', 'Wild', 'Captive', 'Wild']]
>>> index = pd.MultiIndex.from_arrays(arrays, names=('Animal', 'Type'))
>>> ser = pd.Series([390., 350., 30., 20.], index=index, name="Max Speed")
>>> ser
Animal Type
Falcon Captive 390.0
Wild 350.0
Parrot Captive 30.0
Wild 20.0
Name: Max Speed, dtype: float64
>>> ser.groupby(level=0).mean()
Animal
Falcon 370.0
Parrot 25.0
Name: Max Speed, dtype: float64
>>> ser.groupby(level="Type").mean()
Type
Captive 210.0
Wild 185.0
Name: Max Speed, dtype: float64
"""
)
@Appender(generic._shared_docs["groupby"] % _shared_doc_kwargs)
def groupby(
self,
by=None,
axis=0,
level=None,
as_index: bool = True,
sort: bool = True,
group_keys: bool = True,
squeeze: bool = False,
observed: bool = False,
) -> "SeriesGroupBy":
from pandas.core.groupby.generic import SeriesGroupBy
if level is None and by is None:
raise TypeError("You have to supply one of 'by' and 'level'")
axis = self._get_axis_number(axis)
return SeriesGroupBy(
obj=self,
keys=by,
axis=axis,
level=level,
as_index=as_index,
sort=sort,
group_keys=group_keys,
squeeze=squeeze,
observed=observed,
)
# ----------------------------------------------------------------------
# Statistics, overridden ndarray methods
# TODO: integrate bottleneck
def count(self, level=None):
"""
Return number of non-NA/null observations in the Series.
Parameters
----------
level : int or level name, default None
If the axis is a MultiIndex (hierarchical), count along a
particular level, collapsing into a smaller Series.
Returns
-------
int or Series (if level specified)
Number of non-null values in the Series.
See Also
--------
DataFrame.count : Count non-NA cells for each column or row.
Examples
--------
>>> s = pd.Series([0.0, 1.0, np.nan])
>>> s.count()
2
"""
if level is None:
return notna(self.array).sum()
if isinstance(level, str):
level = self.index._get_level_number(level)
lev = self.index.levels[level]
level_codes = np.array(self.index.codes[level], subok=False, copy=True)
mask = level_codes == -1
if mask.any():
level_codes[mask] = cnt = len(lev)
lev = lev.insert(cnt, lev._na_value)
obs = level_codes[notna(self._values)]
out = np.bincount(obs, minlength=len(lev) or None)
return self._constructor(out, index=lev, dtype="int64").__finalize__(
self, method="count"
)
def mode(self, dropna=True) -> "Series":
"""
Return the mode(s) of the dataset.
Always returns Series even if only one value is returned.
Parameters
----------
dropna : bool, default True
Don't consider counts of NaN/NaT.
.. versionadded:: 0.24.0
Returns
-------
Series
Modes of the Series in sorted order.
"""
# TODO: Add option for bins like value_counts()
return algorithms.mode(self, dropna=dropna)
def unique(self):
"""
Return unique values of Series object.
Uniques are returned in order of appearance. Hash table-based unique,
therefore does NOT sort.
Returns
-------
ndarray or ExtensionArray
The unique values returned as a NumPy array. See Notes.
See Also
--------
unique : Top-level unique method for any 1-d array-like object.
Index.unique : Return Index with unique values from an Index object.
Notes
-----
Returns the unique values as a NumPy array. In case of an
extension-array backed Series, a new
:class:`~api.extensions.ExtensionArray` of that type with just
the unique values is returned. This includes
* Categorical
* Period
* Datetime with Timezone
* Interval
* Sparse
* IntegerNA
See Examples section.
Examples
--------
>>> pd.Series([2, 1, 3, 3], name='A').unique()
array([2, 1, 3])
>>> pd.Series([pd.Timestamp('2016-01-01') for _ in range(3)]).unique()
array(['2016-01-01T00:00:00.000000000'], dtype='datetime64[ns]')
>>> pd.Series([pd.Timestamp('2016-01-01', tz='US/Eastern')
... for _ in range(3)]).unique()
<DatetimeArray>
['2016-01-01 00:00:00-05:00']
Length: 1, dtype: datetime64[ns, US/Eastern]
An unordered Categorical will return categories in the order of
appearance.
>>> pd.Series(pd.Categorical(list('baabc'))).unique()
[b, a, c]
Categories (3, object): [b, a, c]
An ordered Categorical preserves the category ordering.
>>> pd.Series(pd.Categorical(list('baabc'), categories=list('abc'),
... ordered=True)).unique()
[b, a, c]
Categories (3, object): [a < b < c]
"""
result = super().unique()
return result
def drop_duplicates(self, keep="first", inplace=False) -> Optional["Series"]:
"""
Return Series with duplicate values removed.
Parameters
----------
keep : {'first', 'last', ``False``}, default 'first'
Method to handle dropping duplicates:
- 'first' : Drop duplicates except for the first occurrence.
- 'last' : Drop duplicates except for the last occurrence.
- ``False`` : Drop all duplicates.
inplace : bool, default ``False``
If ``True``, performs operation inplace and returns None.
Returns
-------
Series
Series with duplicates dropped.
See Also
--------
Index.drop_duplicates : Equivalent method on Index.
DataFrame.drop_duplicates : Equivalent method on DataFrame.
Series.duplicated : Related method on Series, indicating duplicate
Series values.
Examples
--------
Generate a Series with duplicated entries.
>>> s = pd.Series(['lama', 'cow', 'lama', 'beetle', 'lama', 'hippo'],
... name='animal')
>>> s
0 lama
1 cow
2 lama
3 beetle
4 lama
5 hippo
Name: animal, dtype: object
With the 'keep' parameter, the selection behaviour of duplicated values
can be changed. The value 'first' keeps the first occurrence for each
set of duplicated entries. The default value of keep is 'first'.
>>> s.drop_duplicates()
0 lama
1 cow
3 beetle
5 hippo
Name: animal, dtype: object
The value 'last' for parameter 'keep' keeps the last occurrence for
each set of duplicated entries.
>>> s.drop_duplicates(keep='last')
1 cow
3 beetle
4 lama
5 hippo
Name: animal, dtype: object
The value ``False`` for parameter 'keep' discards all sets of
duplicated entries. Setting the value of 'inplace' to ``True`` performs
the operation inplace and returns ``None``.
>>> s.drop_duplicates(keep=False, inplace=True)
>>> s
1 cow
3 beetle
5 hippo
Name: animal, dtype: object
"""
inplace = validate_bool_kwarg(inplace, "inplace")
result = super().drop_duplicates(keep=keep)
if inplace:
self._update_inplace(result)
return None
else:
return result
def duplicated(self, keep="first") -> "Series":
"""
Indicate duplicate Series values.
Duplicated values are indicated as ``True`` values in the resulting
Series. Either all duplicates, all except the first or all except the
last occurrence of duplicates can be indicated.
Parameters
----------
keep : {'first', 'last', False}, default 'first'
Method to handle dropping duplicates:
- 'first' : Mark duplicates as ``True`` except for the first
occurrence.
- 'last' : Mark duplicates as ``True`` except for the last
occurrence.
- ``False`` : Mark all duplicates as ``True``.
Returns
-------
Series
Series indicating whether each value has occurred in the
preceding values.
See Also
--------
Index.duplicated : Equivalent method on pandas.Index.
DataFrame.duplicated : Equivalent method on pandas.DataFrame.
Series.drop_duplicates : Remove duplicate values from Series.
Examples
--------
By default, for each set of duplicated values, the first occurrence is
set on False and all others on True:
>>> animals = pd.Series(['lama', 'cow', 'lama', 'beetle', 'lama'])
>>> animals.duplicated()
0 False
1 False
2 True
3 False
4 True
dtype: bool
which is equivalent to
>>> animals.duplicated(keep='first')
0 False
1 False
2 True
3 False
4 True
dtype: bool
By using 'last', the last occurrence of each set of duplicated values
is set on False and all others on True:
>>> animals.duplicated(keep='last')
0 True
1 False
2 True
3 False
4 False
dtype: bool
By setting keep on ``False``, all duplicates are True:
>>> animals.duplicated(keep=False)
0 True
1 False
2 True
3 False
4 True
dtype: bool
"""
return super().duplicated(keep=keep)
def idxmin(self, axis=0, skipna=True, *args, **kwargs):
"""
Return the row label of the minimum value.
If multiple values equal the minimum, the first row label with that
value is returned.
Parameters
----------
axis : int, default 0
For compatibility with DataFrame.idxmin. Redundant for application
on Series.
skipna : bool, default True
Exclude NA/null values. If the entire Series is NA, the result
will be NA.
*args, **kwargs
Additional arguments and keywords have no effect but might be
accepted for compatibility with NumPy.
Returns
-------
Index
Label of the minimum value.
Raises
------
ValueError
If the Series is empty.
See Also
--------
numpy.argmin : Return indices of the minimum values
along the given axis.
DataFrame.idxmin : Return index of first occurrence of minimum
over requested axis.
Series.idxmax : Return index *label* of the first occurrence
of maximum of values.
Notes
-----
This method is the Series version of ``ndarray.argmin``. This method
returns the label of the minimum, while ``ndarray.argmin`` returns
the position. To get the position, use ``series.values.argmin()``.
Examples
--------
>>> s = pd.Series(data=[1, None, 4, 1],
... index=['A', 'B', 'C', 'D'])
>>> s
A 1.0
B NaN
C 4.0
D 1.0
dtype: float64
>>> s.idxmin()
'A'
If `skipna` is False and there is an NA value in the data,
the function returns ``nan``.
>>> s.idxmin(skipna=False)
nan
"""
skipna = nv.validate_argmin_with_skipna(skipna, args, kwargs)
i = nanops.nanargmin(self._values, skipna=skipna)
if i == -1:
return np.nan
return self.index[i]
def idxmax(self, axis=0, skipna=True, *args, **kwargs):
"""
Return the row label of the maximum value.
If multiple values equal the maximum, the first row label with that
value is returned.
Parameters
----------
axis : int, default 0
For compatibility with DataFrame.idxmax. Redundant for application
on Series.
skipna : bool, default True
Exclude NA/null values. If the entire Series is NA, the result
will be NA.
*args, **kwargs
Additional arguments and keywords have no effect but might be
accepted for compatibility with NumPy.
Returns
-------
Index
Label of the maximum value.
Raises
------
ValueError
If the Series is empty.
See Also
--------
numpy.argmax : Return indices of the maximum values
along the given axis.
DataFrame.idxmax : Return index of first occurrence of maximum
over requested axis.
Series.idxmin : Return index *label* of the first occurrence
of minimum of values.
Notes
-----
This method is the Series version of ``ndarray.argmax``. This method
returns the label of the maximum, while ``ndarray.argmax`` returns
the position. To get the position, use ``series.values.argmax()``.
Examples
--------
>>> s = pd.Series(data=[1, None, 4, 3, 4],
... index=['A', 'B', 'C', 'D', 'E'])
>>> s
A 1.0
B NaN
C 4.0
D 3.0
E 4.0
dtype: float64
>>> s.idxmax()
'C'
If `skipna` is False and there is an NA value in the data,
the function returns ``nan``.
>>> s.idxmax(skipna=False)
nan
"""
skipna = nv.validate_argmax_with_skipna(skipna, args, kwargs)
i = nanops.nanargmax(self._values, skipna=skipna)
if i == -1:
return np.nan
return self.index[i]
def round(self, decimals=0, *args, **kwargs) -> "Series":
"""
Round each value in a Series to the given number of decimals.
Parameters
----------
decimals : int, default 0
Number of decimal places to round to. If decimals is negative,
it specifies the number of positions to the left of the decimal point.
*args, **kwargs
Additional arguments and keywords have no effect but might be
accepted for compatibility with NumPy.
Returns
-------
Series
Rounded values of the Series.
See Also
--------
numpy.around : Round values of an np.array.
DataFrame.round : Round values of a DataFrame.
Examples
--------
>>> s = pd.Series([0.1, 1.3, 2.7])
>>> s.round()
0 0.0
1 1.0
2 3.0
dtype: float64
"""
nv.validate_round(args, kwargs)
result = self._values.round(decimals)
result = self._constructor(result, index=self.index).__finalize__(
self, method="round"
)
return result
def quantile(self, q=0.5, interpolation="linear"):
"""
Return value at the given quantile.
Parameters
----------
q : float or array-like, default 0.5 (50% quantile)
The quantile(s) to compute, which can lie in range: 0 <= q <= 1.
interpolation : {'linear', 'lower', 'higher', 'midpoint', 'nearest'}
This optional parameter specifies the interpolation method to use,
when the desired quantile lies between two data points `i` and `j`:
* linear: `i + (j - i) * fraction`, where `fraction` is the
fractional part of the index surrounded by `i` and `j`.
* lower: `i`.
* higher: `j`.
* nearest: `i` or `j` whichever is nearest.
* midpoint: (`i` + `j`) / 2.
Returns
-------
float or Series
If ``q`` is an array, a Series will be returned where the
index is ``q`` and the values are the quantiles, otherwise
a float will be returned.
See Also
--------
core.window.Rolling.quantile : Calculate the rolling quantile.
numpy.percentile : Returns the q-th percentile(s) of the array elements.
Examples
--------
>>> s = pd.Series([1, 2, 3, 4])
>>> s.quantile(.5)
2.5
>>> s.quantile([.25, .5, .75])
0.25 1.75
0.50 2.50
0.75 3.25
dtype: float64
"""
validate_percentile(q)
# We dispatch to DataFrame so that core.internals only has to worry
# about 2D cases.
df = self.to_frame()
result = df.quantile(q=q, interpolation=interpolation, numeric_only=False)
if result.ndim == 2:
result = result.iloc[:, 0]
if is_list_like(q):
result.name = self.name
return self._constructor(result, index=Float64Index(q), name=self.name)
else:
# scalar
return result.iloc[0]
def corr(self, other, method="pearson", min_periods=None) -> float:
"""
Compute correlation with `other` Series, excluding missing values.
Parameters
----------
other : Series
Series with which to compute the correlation.
method : {'pearson', 'kendall', 'spearman'} or callable
Method used to compute correlation:
- pearson : Standard correlation coefficient
- kendall : Kendall Tau correlation coefficient
- spearman : Spearman rank correlation
- callable: Callable with input two 1d ndarrays and returning a float.
.. versionadded:: 0.24.0
Note that the returned matrix from corr will have 1 along the
diagonals and will be symmetric regardless of the callable's
behavior.
min_periods : int, optional
Minimum number of observations needed to have a valid result.
Returns
-------
float
Correlation with other.
See Also
--------
DataFrame.corr : Compute pairwise correlation between columns.
DataFrame.corrwith : Compute pairwise correlation with another
DataFrame or Series.
Examples
--------
>>> def histogram_intersection(a, b):
... v = np.minimum(a, b).sum().round(decimals=1)
... return v
>>> s1 = pd.Series([.2, .0, .6, .2])
>>> s2 = pd.Series([.3, .6, .0, .1])
>>> s1.corr(s2, method=histogram_intersection)
0.3
"""
this, other = self.align(other, join="inner", copy=False)
if len(this) == 0:
return np.nan
if method in ["pearson", "spearman", "kendall"] or callable(method):
return nanops.nancorr(
this.values, other.values, method=method, min_periods=min_periods
)
raise ValueError(
"method must be either 'pearson', "
"'spearman', 'kendall', or a callable, "
f"'{method}' was supplied"
)
def cov(self, other, min_periods=None) -> float:
"""
Compute covariance with Series, excluding missing values.
Parameters
----------
other : Series
Series with which to compute the covariance.
min_periods : int, optional
Minimum number of observations needed to have a valid result.
Returns
-------
float
Covariance between Series and other normalized by N-1
(unbiased estimator).
See Also
--------
DataFrame.cov : Compute pairwise covariance of columns.
Examples
--------
>>> s1 = pd.Series([0.90010907, 0.13484424, 0.62036035])
>>> s2 = pd.Series([0.12528585, 0.26962463, 0.51111198])
>>> s1.cov(s2)
-0.01685762652715874
"""
this, other = self.align(other, join="inner", copy=False)
if len(this) == 0:
return np.nan
return nanops.nancov(this.values, other.values, min_periods=min_periods)
def diff(self, periods: int = 1) -> "Series":
"""
First discrete difference of element.
Calculates the difference of a Series element compared with another
element in the Series (default is element in previous row).
Parameters
----------
periods : int, default 1
Periods to shift for calculating difference, accepts negative
values.
Returns
-------
Series
First differences of the Series.
See Also
--------
Series.pct_change: Percent change over given number of periods.
Series.shift: Shift index by desired number of periods with an
optional time freq.
DataFrame.diff: First discrete difference of object.
Notes
-----
For boolean dtypes, this uses :meth:`operator.xor` rather than
:meth:`operator.sub`.
Examples
--------
Difference with previous row
>>> s = pd.Series([1, 1, 2, 3, 5, 8])
>>> s.diff()
0 NaN
1 0.0
2 1.0
3 1.0
4 2.0
5 3.0
dtype: float64
Difference with 3rd previous row
>>> s.diff(periods=3)
0 NaN
1 NaN
2 NaN
3 2.0
4 4.0
5 6.0
dtype: float64
Difference with following row
>>> s.diff(periods=-1)
0 0.0
1 -1.0
2 -1.0
3 -2.0
4 -3.0
5 NaN
dtype: float64
"""
result = algorithms.diff(self.array, periods)
return self._constructor(result, index=self.index).__finalize__(
self, method="diff"
)
def autocorr(self, lag=1) -> float:
"""
Compute the lag-N autocorrelation.
This method computes the Pearson correlation between
the Series and its shifted self.
Parameters
----------
lag : int, default 1
Number of lags to apply before performing autocorrelation.
Returns
-------
float
The Pearson correlation between self and self.shift(lag).
See Also
--------
Series.corr : Compute the correlation between two Series.
Series.shift : Shift index by desired number of periods.
DataFrame.corr : Compute pairwise correlation of columns.
DataFrame.corrwith : Compute pairwise correlation between rows or
columns of two DataFrame objects.
Notes
-----
If the Pearson correlation is not well defined return 'NaN'.
Examples
--------
>>> s = pd.Series([0.25, 0.5, 0.2, -0.05])
>>> s.autocorr() # doctest: +ELLIPSIS
0.10355...
>>> s.autocorr(lag=2) # doctest: +ELLIPSIS
-0.99999...
If the Pearson correlation is not well defined, then 'NaN' is returned.
>>> s = pd.Series([1, 0, 0, 0])
>>> s.autocorr()
nan
"""
return self.corr(self.shift(lag))
def dot(self, other):
"""
Compute the dot product between the Series and the columns of other.
This method computes the dot product between the Series and another
one, or the Series and each columns of a DataFrame, or the Series and
each columns of an array.
It can also be called using `self @ other` in Python >= 3.5.
Parameters
----------
other : Series, DataFrame or array-like
The other object to compute the dot product with its columns.
Returns
-------
scalar, Series or numpy.ndarray
Return the dot product of the Series and other if other is a
Series, the Series of the dot product of Series and each rows of
other if other is a DataFrame or a numpy.ndarray between the Series
and each columns of the numpy array.
See Also
--------
DataFrame.dot: Compute the matrix product with the DataFrame.
Series.mul: Multiplication of series and other, element-wise.
Notes
-----
The Series and other has to share the same index if other is a Series
or a DataFrame.
Examples
--------
>>> s = pd.Series([0, 1, 2, 3])
>>> other = pd.Series([-1, 2, -3, 4])
>>> s.dot(other)
8
>>> s @ other
8
>>> df = pd.DataFrame([[0, 1], [-2, 3], [4, -5], [6, 7]])
>>> s.dot(df)
0 24
1 14
dtype: int64
>>> arr = np.array([[0, 1], [-2, 3], [4, -5], [6, 7]])
>>> s.dot(arr)
array([24, 14])
"""
if isinstance(other, (Series, ABCDataFrame)):
common = self.index.union(other.index)
if len(common) > len(self.index) or len(common) > len(other.index):
raise ValueError("matrices are not aligned")
left = self.reindex(index=common, copy=False)
right = other.reindex(index=common, copy=False)
lvals = left.values
rvals = right.values
else:
lvals = self.values
rvals = np.asarray(other)
if lvals.shape[0] != rvals.shape[0]:
raise Exception(
f"Dot product shape mismatch, {lvals.shape} vs {rvals.shape}"
)
if isinstance(other, ABCDataFrame):
return self._constructor(
np.dot(lvals, rvals), index=other.columns
).__finalize__(self, method="dot")
elif isinstance(other, Series):
return np.dot(lvals, rvals)
elif isinstance(rvals, np.ndarray):
return np.dot(lvals, rvals)
else: # pragma: no cover
raise TypeError(f"unsupported type: {type(other)}")
def __matmul__(self, other):
"""
Matrix multiplication using binary `@` operator in Python>=3.5.
"""
return self.dot(other)
def __rmatmul__(self, other):
"""
Matrix multiplication using binary `@` operator in Python>=3.5.
"""
return self.dot(np.transpose(other))
@doc(base.IndexOpsMixin.searchsorted, klass="Series")
def searchsorted(self, value, side="left", sorter=None):
return algorithms.searchsorted(self._values, value, side=side, sorter=sorter)
# -------------------------------------------------------------------
# Combination
def append(self, to_append, ignore_index=False, verify_integrity=False):
"""
Concatenate two or more Series.
Parameters
----------
to_append : Series or list/tuple of Series
Series to append with self.
ignore_index : bool, default False
If True, do not use the index labels.
verify_integrity : bool, default False
If True, raise Exception on creating index with duplicates.
Returns
-------
Series
Concatenated Series.
See Also
--------
concat : General function to concatenate DataFrame or Series objects.
Notes
-----
Iteratively appending to a Series can be more computationally intensive
than a single concatenate. A better solution is to append values to a
list and then concatenate the list with the original Series all at
once.
Examples
--------
>>> s1 = pd.Series([1, 2, 3])
>>> s2 = pd.Series([4, 5, 6])
>>> s3 = pd.Series([4, 5, 6], index=[3, 4, 5])
>>> s1.append(s2)
0 1
1 2
2 3
0 4
1 5
2 6
dtype: int64
>>> s1.append(s3)
0 1
1 2
2 3
3 4
4 5
5 6
dtype: int64
With `ignore_index` set to True:
>>> s1.append(s2, ignore_index=True)
0 1
1 2
2 3
3 4
4 5
5 6
dtype: int64
With `verify_integrity` set to True:
>>> s1.append(s2, verify_integrity=True)
Traceback (most recent call last):
...
ValueError: Indexes have overlapping values: [0, 1, 2]
"""
from pandas.core.reshape.concat import concat
if isinstance(to_append, (list, tuple)):
to_concat = [self]
to_concat.extend(to_append)
else:
to_concat = [self, to_append]
if any(isinstance(x, (ABCDataFrame,)) for x in to_concat[1:]):
msg = (
f"to_append should be a Series or list/tuple of Series, "
f"got DataFrame"
)
raise TypeError(msg)
return concat(
to_concat, ignore_index=ignore_index, verify_integrity=verify_integrity
)
def _binop(self, other, func, level=None, fill_value=None):
"""
Perform generic binary operation with optional fill value.
Parameters
----------
other : Series
func : binary operator
fill_value : float or object
Value to substitute for NA/null values. If both Series are NA in a
location, the result will be NA regardless of the passed fill value.
level : int or level name, default None
Broadcast across a level, matching Index values on the
passed MultiIndex level.
Returns
-------
Series
"""
if not isinstance(other, Series):
raise AssertionError("Other operand must be Series")
this = self
if not self.index.equals(other.index):
this, other = self.align(other, level=level, join="outer", copy=False)
this_vals, other_vals = ops.fill_binop(this.values, other.values, fill_value)
with np.errstate(all="ignore"):
result = func(this_vals, other_vals)
name = ops.get_op_result_name(self, other)
ret = this._construct_result(result, name)
return ret
def _construct_result(
self, result: Union[ArrayLike, Tuple[ArrayLike, ArrayLike]], name: Label
) -> Union["Series", Tuple["Series", "Series"]]:
"""
Construct an appropriately-labelled Series from the result of an op.
Parameters
----------
result : ndarray or ExtensionArray
name : Label
Returns
-------
Series
In the case of __divmod__ or __rdivmod__, a 2-tuple of Series.
"""
if isinstance(result, tuple):
# produced by divmod or rdivmod
res1 = self._construct_result(result[0], name=name)
res2 = self._construct_result(result[1], name=name)
# GH#33427 assertions to keep mypy happy
assert isinstance(res1, Series)
assert isinstance(res2, Series)
return (res1, res2)
# We do not pass dtype to ensure that the Series constructor
# does inference in the case where `result` has object-dtype.
out = self._constructor(result, index=self.index)
out = out.__finalize__(self)
# Set the result's name after __finalize__ is called because __finalize__
# would set it back to self.name
out.name = name
return out
def combine(self, other, func, fill_value=None) -> "Series":
"""
Combine the Series with a Series or scalar according to `func`.
Combine the Series and `other` using `func` to perform elementwise
selection for combined Series.
`fill_value` is assumed when value is missing at some index
from one of the two objects being combined.
Parameters
----------
other : Series or scalar
The value(s) to be combined with the `Series`.
func : function
Function that takes two scalars as inputs and returns an element.
fill_value : scalar, optional
The value to assume when an index is missing from
one Series or the other. The default specifies to use the
appropriate NaN value for the underlying dtype of the Series.
Returns
-------
Series
The result of combining the Series with the other object.
See Also
--------
Series.combine_first : Combine Series values, choosing the calling
Series' values first.
Examples
--------
Consider 2 Datasets ``s1`` and ``s2`` containing
highest clocked speeds of different birds.
>>> s1 = pd.Series({'falcon': 330.0, 'eagle': 160.0})
>>> s1
falcon 330.0
eagle 160.0
dtype: float64
>>> s2 = pd.Series({'falcon': 345.0, 'eagle': 200.0, 'duck': 30.0})
>>> s2
falcon 345.0
eagle 200.0
duck 30.0
dtype: float64
Now, to combine the two datasets and view the highest speeds
of the birds across the two datasets
>>> s1.combine(s2, max)
duck NaN
eagle 200.0
falcon 345.0
dtype: float64
In the previous example, the resulting value for duck is missing,
because the maximum of a NaN and a float is a NaN.
So, in the example, we set ``fill_value=0``,
so the maximum value returned will be the value from some dataset.
>>> s1.combine(s2, max, fill_value=0)
duck 30.0
eagle 200.0
falcon 345.0
dtype: float64
"""
if fill_value is None:
fill_value = na_value_for_dtype(self.dtype, compat=False)
if isinstance(other, Series):
# If other is a Series, result is based on union of Series,
# so do this element by element
new_index = self.index.union(other.index)
new_name = ops.get_op_result_name(self, other)
new_values = []
for idx in new_index:
lv = self.get(idx, fill_value)
rv = other.get(idx, fill_value)
with np.errstate(all="ignore"):
new_values.append(func(lv, rv))
else:
# Assume that other is a scalar, so apply the function for
# each element in the Series
new_index = self.index
with np.errstate(all="ignore"):
new_values = [func(lv, other) for lv in self._values]
new_name = self.name
if is_categorical_dtype(self.dtype):
pass
elif is_extension_array_dtype(self.dtype):
# TODO: can we do this for only SparseDtype?
# The function can return something of any type, so check
# if the type is compatible with the calling EA.
new_values = maybe_cast_to_extension_array(type(self._values), new_values)
return self._constructor(new_values, index=new_index, name=new_name)
def combine_first(self, other) -> "Series":
"""
Combine Series values, choosing the calling Series's values first.
Parameters
----------
other : Series
The value(s) to be combined with the `Series`.
Returns
-------
Series
The result of combining the Series with the other object.
See Also
--------
Series.combine : Perform elementwise operation on two Series
using a given function.
Notes
-----
Result index will be the union of the two indexes.
Examples
--------
>>> s1 = pd.Series([1, np.nan])
>>> s2 = pd.Series([3, 4])
>>> s1.combine_first(s2)
0 1.0
1 4.0
dtype: float64
"""
new_index = self.index.union(other.index)
this = self.reindex(new_index, copy=False)
other = other.reindex(new_index, copy=False)
if this.dtype.kind == "M" and other.dtype.kind != "M":
other = to_datetime(other)
return this.where(notna(this), other)
def update(self, other) -> None:
"""
Modify Series in place using non-NA values from passed
Series. Aligns on index.
Parameters
----------
other : Series
Examples
--------
>>> s = pd.Series([1, 2, 3])
>>> s.update(pd.Series([4, 5, 6]))
>>> s
0 4
1 5
2 6
dtype: int64
>>> s = pd.Series(['a', 'b', 'c'])
>>> s.update(pd.Series(['d', 'e'], index=[0, 2]))
>>> s
0 d
1 b
2 e
dtype: object
>>> s = pd.Series([1, 2, 3])
>>> s.update(pd.Series([4, 5, 6, 7, 8]))
>>> s
0 4
1 5
2 6
dtype: int64
If ``other`` contains NaNs the corresponding values are not updated
in the original Series.
>>> s = pd.Series([1, 2, 3])
>>> s.update(pd.Series([4, np.nan, 6]))
>>> s
0 4
1 2
2 6
dtype: int64
"""
other = other.reindex_like(self)
mask = notna(other)
self._mgr = self._mgr.putmask(mask=mask, new=other)
self._maybe_update_cacher()
# ----------------------------------------------------------------------
# Reindexing, sorting
def sort_values(
self,
axis=0,
ascending=True,
inplace: bool = False,
kind: str = "quicksort",
na_position: str = "last",
ignore_index: bool = False,
):
"""
Sort by the values.
Sort a Series in ascending or descending order by some
criterion.
Parameters
----------
axis : {0 or 'index'}, default 0
Axis to direct sorting. The value 'index' is accepted for
compatibility with DataFrame.sort_values.
ascending : bool, default True
If True, sort values in ascending order, otherwise descending.
inplace : bool, default False
If True, perform operation in-place.
kind : {'quicksort', 'mergesort' or 'heapsort'}, default 'quicksort'
Choice of sorting algorithm. See also :func:`numpy.sort` for more
information. 'mergesort' is the only stable algorithm.
na_position : {'first' or 'last'}, default 'last'
Argument 'first' puts NaNs at the beginning, 'last' puts NaNs at
the end.
ignore_index : bool, default False
If True, the resulting axis will be labeled 0, 1, …, n - 1.
.. versionadded:: 1.0.0
Returns
-------
Series
Series ordered by values.
See Also
--------
Series.sort_index : Sort by the Series indices.
DataFrame.sort_values : Sort DataFrame by the values along either axis.
DataFrame.sort_index : Sort DataFrame by indices.
Examples
--------
>>> s = pd.Series([np.nan, 1, 3, 10, 5])
>>> s
0 NaN
1 1.0
2 3.0
3 10.0
4 5.0
dtype: float64
Sort values ascending order (default behaviour)
>>> s.sort_values(ascending=True)
1 1.0
2 3.0
4 5.0
3 10.0
0 NaN
dtype: float64
Sort values descending order
>>> s.sort_values(ascending=False)
3 10.0
4 5.0
2 3.0
1 1.0
0 NaN
dtype: float64
Sort values inplace
>>> s.sort_values(ascending=False, inplace=True)
>>> s
3 10.0
4 5.0
2 3.0
1 1.0
0 NaN
dtype: float64
Sort values putting NAs first
>>> s.sort_values(na_position='first')
0 NaN
1 1.0
2 3.0
4 5.0
3 10.0
dtype: float64
Sort a series of strings
>>> s = pd.Series(['z', 'b', 'd', 'a', 'c'])
>>> s
0 z
1 b
2 d
3 a
4 c
dtype: object
>>> s.sort_values()
3 a
1 b
4 c
2 d
0 z
dtype: object
"""
inplace = validate_bool_kwarg(inplace, "inplace")
# Validate the axis parameter
self._get_axis_number(axis)
# GH 5856/5853
if inplace and self._is_cached:
raise ValueError(
"This Series is a view of some other array, to "
"sort in-place you must create a copy"
)
def _try_kind_sort(arr):
# easier to ask forgiveness than permission
try:
# if kind==mergesort, it can fail for object dtype
return arr.argsort(kind=kind)
except TypeError:
# stable sort not available for object dtype
# uses the argsort default quicksort
return arr.argsort(kind="quicksort")
arr = self._values
sorted_index = np.empty(len(self), dtype=np.int32)
bad = isna(arr)
good = ~bad
idx = ibase.default_index(len(self))
argsorted = _try_kind_sort(arr[good])
if is_list_like(ascending):
if len(ascending) != 1:
raise ValueError(
f"Length of ascending ({len(ascending)}) must be 1 for Series"
)
ascending = ascending[0]
if not is_bool(ascending):
raise ValueError("ascending must be boolean")
if not ascending:
argsorted = argsorted[::-1]
if na_position == "last":
n = good.sum()
sorted_index[:n] = idx[good][argsorted]
sorted_index[n:] = idx[bad]
elif na_position == "first":
n = bad.sum()
sorted_index[n:] = idx[good][argsorted]
sorted_index[:n] = idx[bad]
else:
raise ValueError(f"invalid na_position: {na_position}")
result = self._constructor(arr[sorted_index], index=self.index[sorted_index])
if ignore_index:
result.index = ibase.default_index(len(sorted_index))
if inplace:
self._update_inplace(result)
else:
return result.__finalize__(self, method="sort_values")
def sort_index(
self,
axis=0,
level=None,
ascending: bool = True,
inplace: bool = False,
kind: str = "quicksort",
na_position: str = "last",
sort_remaining: bool = True,
ignore_index: bool = False,
):
"""
Sort Series by index labels.
Returns a new Series sorted by label if `inplace` argument is
``False``, otherwise updates the original series and returns None.
Parameters
----------
axis : int, default 0
Axis to direct sorting. This can only be 0 for Series.
level : int, optional
If not None, sort on values in specified index level(s).
ascending : bool or list of bools, default True
Sort ascending vs. descending. When the index is a MultiIndex the
sort direction can be controlled for each level individually.
inplace : bool, default False
If True, perform operation in-place.
kind : {'quicksort', 'mergesort', 'heapsort'}, default 'quicksort'
Choice of sorting algorithm. See also :func:`numpy.sort` for more
information. 'mergesort' is the only stable algorithm. For
DataFrames, this option is only applied when sorting on a single
column or label.
na_position : {'first', 'last'}, default 'last'
If 'first' puts NaNs at the beginning, 'last' puts NaNs at the end.
Not implemented for MultiIndex.
sort_remaining : bool, default True
If True and sorting by level and index is multilevel, sort by other
levels too (in order) after sorting by specified level.
ignore_index : bool, default False
If True, the resulting axis will be labeled 0, 1, …, n - 1.
.. versionadded:: 1.0.0
Returns
-------
Series
The original Series sorted by the labels.
See Also
--------
DataFrame.sort_index: Sort DataFrame by the index.
DataFrame.sort_values: Sort DataFrame by the value.
Series.sort_values : Sort Series by the value.
Examples
--------
>>> s = pd.Series(['a', 'b', 'c', 'd'], index=[3, 2, 1, 4])
>>> s.sort_index()
1 c
2 b
3 a
4 d
dtype: object
Sort Descending
>>> s.sort_index(ascending=False)
4 d
3 a
2 b
1 c
dtype: object
Sort Inplace
>>> s.sort_index(inplace=True)
>>> s
1 c
2 b
3 a
4 d
dtype: object
By default NaNs are put at the end, but use `na_position` to place
them at the beginning
>>> s = pd.Series(['a', 'b', 'c', 'd'], index=[3, 2, 1, np.nan])
>>> s.sort_index(na_position='first')
NaN d
1.0 c
2.0 b
3.0 a
dtype: object
Specify index level to sort
>>> arrays = [np.array(['qux', 'qux', 'foo', 'foo',
... 'baz', 'baz', 'bar', 'bar']),
... np.array(['two', 'one', 'two', 'one',
... 'two', 'one', 'two', 'one'])]
>>> s = pd.Series([1, 2, 3, 4, 5, 6, 7, 8], index=arrays)
>>> s.sort_index(level=1)
bar one 8
baz one 6
foo one 4
qux one 2
bar two 7
baz two 5
foo two 3
qux two 1
dtype: int64
Does not sort by remaining levels when sorting by levels
>>> s.sort_index(level=1, sort_remaining=False)
qux one 2
foo one 4
baz one 6
bar one 8
qux two 1
foo two 3
baz two 5
bar two 7
dtype: int64
"""
# TODO: this can be combined with DataFrame.sort_index impl as
# almost identical
inplace = validate_bool_kwarg(inplace, "inplace")
# Validate the axis parameter
self._get_axis_number(axis)
index = self.index
if level is not None:
new_index, indexer = index.sortlevel(
level, ascending=ascending, sort_remaining=sort_remaining
)
elif isinstance(index, MultiIndex):
from pandas.core.sorting import lexsort_indexer
labels = index._sort_levels_monotonic()
indexer = lexsort_indexer(
labels._get_codes_for_sorting(),
orders=ascending,
na_position=na_position,
)
else:
from pandas.core.sorting import nargsort
# Check monotonic-ness before sort an index
# GH11080
if (ascending and index.is_monotonic_increasing) or (
not ascending and index.is_monotonic_decreasing
):
if inplace:
return
else:
return self.copy()
indexer = nargsort(
index, kind=kind, ascending=ascending, na_position=na_position
)
indexer = ensure_platform_int(indexer)
new_index = index.take(indexer)
new_index = new_index._sort_levels_monotonic()
new_values = self._values.take(indexer)
result = self._constructor(new_values, index=new_index)
if ignore_index:
result.index = ibase.default_index(len(result))
if inplace:
self._update_inplace(result)
else:
return result.__finalize__(self, method="sort_index")
def argsort(self, axis=0, kind="quicksort", order=None) -> "Series":
"""
Override ndarray.argsort. Argsorts the value, omitting NA/null values,
and places the result in the same locations as the non-NA values.
Parameters
----------
axis : {0 or "index"}
Has no effect but is accepted for compatibility with numpy.
kind : {'mergesort', 'quicksort', 'heapsort'}, default 'quicksort'
Choice of sorting algorithm. See np.sort for more
information. 'mergesort' is the only stable algorithm.
order : None
Has no effect but is accepted for compatibility with numpy.
Returns
-------
Series
Positions of values within the sort order with -1 indicating
nan values.
See Also
--------
numpy.ndarray.argsort : Returns the indices that would sort this array.
"""
values = self._values
mask = isna(values)
if mask.any():
result = Series(-1, index=self.index, name=self.name, dtype="int64")
notmask = ~mask
result[notmask] = np.argsort(values[notmask], kind=kind)
return self._constructor(result, index=self.index).__finalize__(
self, method="argsort"
)
else:
return self._constructor(
np.argsort(values, kind=kind), index=self.index, dtype="int64"
).__finalize__(self, method="argsort")
def nlargest(self, n=5, keep="first") -> "Series":
"""
Return the largest `n` elements.
Parameters
----------
n : int, default 5
Return this many descending sorted values.
keep : {'first', 'last', 'all'}, default 'first'
When there are duplicate values that cannot all fit in a
Series of `n` elements:
- ``first`` : return the first `n` occurrences in order
of appearance.
- ``last`` : return the last `n` occurrences in reverse
order of appearance.
- ``all`` : keep all occurrences. This can result in a Series of
size larger than `n`.
Returns
-------
Series
The `n` largest values in the Series, sorted in decreasing order.
See Also
--------
Series.nsmallest: Get the `n` smallest elements.
Series.sort_values: Sort Series by values.
Series.head: Return the first `n` rows.
Notes
-----
Faster than ``.sort_values(ascending=False).head(n)`` for small `n`
relative to the size of the ``Series`` object.
Examples
--------
>>> countries_population = {"Italy": 59000000, "France": 65000000,
... "Malta": 434000, "Maldives": 434000,
... "Brunei": 434000, "Iceland": 337000,
... "Nauru": 11300, "Tuvalu": 11300,
... "Anguilla": 11300, "Monserat": 5200}
>>> s = pd.Series(countries_population)
>>> s
Italy 59000000
France 65000000
Malta 434000
Maldives 434000
Brunei 434000
Iceland 337000
Nauru 11300
Tuvalu 11300
Anguilla 11300
Monserat 5200
dtype: int64
The `n` largest elements where ``n=5`` by default.
>>> s.nlargest()
France 65000000
Italy 59000000
Malta 434000
Maldives 434000
Brunei 434000
dtype: int64
The `n` largest elements where ``n=3``. Default `keep` value is 'first'
so Malta will be kept.
>>> s.nlargest(3)
France 65000000
Italy 59000000
Malta 434000
dtype: int64
The `n` largest elements where ``n=3`` and keeping the last duplicates.
Brunei will be kept since it is the last with value 434000 based on
the index order.
>>> s.nlargest(3, keep='last')
France 65000000
Italy 59000000
Brunei 434000
dtype: int64
The `n` largest elements where ``n=3`` with all duplicates kept. Note
that the returned Series has five elements due to the three duplicates.
>>> s.nlargest(3, keep='all')
France 65000000
Italy 59000000
Malta 434000
Maldives 434000
Brunei 434000
dtype: int64
"""
return algorithms.SelectNSeries(self, n=n, keep=keep).nlargest()
def nsmallest(self, n=5, keep="first") -> "Series":
"""
Return the smallest `n` elements.
Parameters
----------
n : int, default 5
Return this many ascending sorted values.
keep : {'first', 'last', 'all'}, default 'first'
When there are duplicate values that cannot all fit in a
Series of `n` elements:
- ``first`` : return the first `n` occurrences in order
of appearance.
- ``last`` : return the last `n` occurrences in reverse
order of appearance.
- ``all`` : keep all occurrences. This can result in a Series of
size larger than `n`.
Returns
-------
Series
The `n` smallest values in the Series, sorted in increasing order.
See Also
--------
Series.nlargest: Get the `n` largest elements.
Series.sort_values: Sort Series by values.
Series.head: Return the first `n` rows.
Notes
-----
Faster than ``.sort_values().head(n)`` for small `n` relative to
the size of the ``Series`` object.
Examples
--------
>>> countries_population = {"Italy": 59000000, "France": 65000000,
... "Brunei": 434000, "Malta": 434000,
... "Maldives": 434000, "Iceland": 337000,
... "Nauru": 11300, "Tuvalu": 11300,
... "Anguilla": 11300, "Monserat": 5200}
>>> s = pd.Series(countries_population)
>>> s
Italy 59000000
France 65000000
Brunei 434000
Malta 434000
Maldives 434000
Iceland 337000
Nauru 11300
Tuvalu 11300
Anguilla 11300
Monserat 5200
dtype: int64
The `n` smallest elements where ``n=5`` by default.
>>> s.nsmallest()
Monserat 5200
Nauru 11300
Tuvalu 11300
Anguilla 11300
Iceland 337000
dtype: int64
The `n` smallest elements where ``n=3``. Default `keep` value is
'first' so Nauru and Tuvalu will be kept.
>>> s.nsmallest(3)
Monserat 5200
Nauru 11300
Tuvalu 11300
dtype: int64
The `n` smallest elements where ``n=3`` and keeping the last
duplicates. Anguilla and Tuvalu will be kept since they are the last
with value 11300 based on the index order.
>>> s.nsmallest(3, keep='last')
Monserat 5200
Anguilla 11300
Tuvalu 11300
dtype: int64
The `n` smallest elements where ``n=3`` with all duplicates kept. Note
that the returned Series has four elements due to the three duplicates.
>>> s.nsmallest(3, keep='all')
Monserat 5200
Nauru 11300
Tuvalu 11300
Anguilla 11300
dtype: int64
"""
return algorithms.SelectNSeries(self, n=n, keep=keep).nsmallest()
def swaplevel(self, i=-2, j=-1, copy=True) -> "Series":
"""
Swap levels i and j in a :class:`MultiIndex`.
Default is to swap the two innermost levels of the index.
Parameters
----------
i, j : int, str
Level of the indices to be swapped. Can pass level name as string.
copy : bool, default True
Whether to copy underlying data.
Returns
-------
Series
Series with levels swapped in MultiIndex.
"""
assert isinstance(self.index, ABCMultiIndex)
new_index = self.index.swaplevel(i, j)
return self._constructor(self._values, index=new_index, copy=copy).__finalize__(
self, method="swaplevel"
)
def reorder_levels(self, order) -> "Series":
"""
Rearrange index levels using input order.
May not drop or duplicate levels.
Parameters
----------
order : list of int representing new level order
Reference level by number or key.
Returns
-------
type of caller (new object)
"""
if not isinstance(self.index, MultiIndex): # pragma: no cover
raise Exception("Can only reorder levels on a hierarchical axis.")
result = self.copy()
assert isinstance(result.index, ABCMultiIndex)
result.index = result.index.reorder_levels(order)
return result
def explode(self) -> "Series":
"""
Transform each element of a list-like to a row, replicating the
index values.
.. versionadded:: 0.25.0
Returns
-------
Series
Exploded lists to rows; index will be duplicated for these rows.
See Also
--------
Series.str.split : Split string values on specified separator.
Series.unstack : Unstack, a.k.a. pivot, Series with MultiIndex
to produce DataFrame.
DataFrame.melt : Unpivot a DataFrame from wide format to long format.
DataFrame.explode : Explode a DataFrame from list-like
columns to long format.
Notes
-----
This routine will explode list-likes including lists, tuples,
Series, and np.ndarray. The result dtype of the subset rows will
be object. Scalars will be returned unchanged. Empty list-likes will
result in a np.nan for that row.
Examples
--------
>>> s = pd.Series([[1, 2, 3], 'foo', [], [3, 4]])
>>> s
0 [1, 2, 3]
1 foo
2 []
3 [3, 4]
dtype: object
>>> s.explode()
0 1
0 2
0 3
1 foo
2 NaN
3 3
3 4
dtype: object
"""
if not len(self) or not is_object_dtype(self):
return self.copy()
values, counts = reshape.explode(np.asarray(self.array))
result = Series(values, index=self.index.repeat(counts), name=self.name)
return result
def unstack(self, level=-1, fill_value=None):
"""
Unstack, also known as pivot, Series with MultiIndex to produce DataFrame.
The level involved will automatically get sorted.
Parameters
----------
level : int, str, or list of these, default last level
Level(s) to unstack, can pass level name.
fill_value : scalar value, default None
Value to use when replacing NaN values.
Returns
-------
DataFrame
Unstacked Series.
Examples
--------
>>> s = pd.Series([1, 2, 3, 4],
... index=pd.MultiIndex.from_product([['one', 'two'],
... ['a', 'b']]))
>>> s
one a 1
b 2
two a 3
b 4
dtype: int64
>>> s.unstack(level=-1)
a b
one 1 2
two 3 4
>>> s.unstack(level=0)
one two
a 1 3
b 2 4
"""
from pandas.core.reshape.reshape import unstack
return unstack(self, level, fill_value)
# ----------------------------------------------------------------------
# function application
def map(self, arg, na_action=None) -> "Series":
"""
Map values of Series according to input correspondence.
Used for substituting each value in a Series with another value,
that may be derived from a function, a ``dict`` or
a :class:`Series`.
Parameters
----------
arg : function, collections.abc.Mapping subclass or Series
Mapping correspondence.
na_action : {None, 'ignore'}, default None
If 'ignore', propagate NaN values, without passing them to the
mapping correspondence.
Returns
-------
Series
Same index as caller.
See Also
--------
Series.apply : For applying more complex functions on a Series.
DataFrame.apply : Apply a function row-/column-wise.
DataFrame.applymap : Apply a function elementwise on a whole DataFrame.
Notes
-----
When ``arg`` is a dictionary, values in Series that are not in the
dictionary (as keys) are converted to ``NaN``. However, if the
dictionary is a ``dict`` subclass that defines ``__missing__`` (i.e.
provides a method for default values), then this default is used
rather than ``NaN``.
Examples
--------
>>> s = pd.Series(['cat', 'dog', np.nan, 'rabbit'])
>>> s
0 cat
1 dog
2 NaN
3 rabbit
dtype: object
``map`` accepts a ``dict`` or a ``Series``. Values that are not found
in the ``dict`` are converted to ``NaN``, unless the dict has a default
value (e.g. ``defaultdict``):
>>> s.map({'cat': 'kitten', 'dog': 'puppy'})
0 kitten
1 puppy
2 NaN
3 NaN
dtype: object
It also accepts a function:
>>> s.map('I am a {}'.format)
0 I am a cat
1 I am a dog
2 I am a nan
3 I am a rabbit
dtype: object
To avoid applying the function to missing values (and keep them as
``NaN``) ``na_action='ignore'`` can be used:
>>> s.map('I am a {}'.format, na_action='ignore')
0 I am a cat
1 I am a dog
2 NaN
3 I am a rabbit
dtype: object
"""
new_values = super()._map_values(arg, na_action=na_action)
return self._constructor(new_values, index=self.index).__finalize__(
self, method="map"
)
def _gotitem(self, key, ndim, subset=None) -> "Series":
"""
Sub-classes to define. Return a sliced object.
Parameters
----------
key : string / list of selections
ndim : 1,2
Requested ndim of result.
subset : object, default None
Subset to act on.
"""
return self
_agg_see_also_doc = dedent(
"""
See Also
--------
Series.apply : Invoke function on a Series.
Series.transform : Transform function producing a Series with like indexes.
"""
)
_agg_examples_doc = dedent(
"""
Examples
--------
>>> s = pd.Series([1, 2, 3, 4])
>>> s
0 1
1 2
2 3
3 4
dtype: int64
>>> s.agg('min')
1
>>> s.agg(['min', 'max'])
min 1
max 4
dtype: int64
"""
)
@Substitution(
see_also=_agg_see_also_doc,
examples=_agg_examples_doc,
versionadded="\n.. versionadded:: 0.20.0\n",
**_shared_doc_kwargs,
)
@Appender(generic._shared_docs["aggregate"])
def aggregate(self, func, axis=0, *args, **kwargs):
# Validate the axis parameter
self._get_axis_number(axis)
result, how = self._aggregate(func, *args, **kwargs)
if result is None:
# we can be called from an inner function which
# passes this meta-data
kwargs.pop("_axis", None)
kwargs.pop("_level", None)
# try a regular apply, this evaluates lambdas
# row-by-row; however if the lambda is expected a Series
# expression, e.g.: lambda x: x-x.quantile(0.25)
# this will fail, so we can try a vectorized evaluation
# we cannot FIRST try the vectorized evaluation, because
# then .agg and .apply would have different semantics if the
# operation is actually defined on the Series, e.g. str
try:
result = self.apply(func, *args, **kwargs)
except (ValueError, AttributeError, TypeError):
result = func(self, *args, **kwargs)
return result
agg = aggregate
@Appender(generic._shared_docs["transform"] % _shared_doc_kwargs)
def transform(self, func, axis=0, *args, **kwargs):
# Validate the axis parameter
self._get_axis_number(axis)
return super().transform(func, *args, **kwargs)
def apply(self, func, convert_dtype=True, args=(), **kwds):
"""
Invoke function on values of Series.
Can be ufunc (a NumPy function that applies to the entire Series)
or a Python function that only works on single values.
Parameters
----------
func : function
Python function or NumPy ufunc to apply.
convert_dtype : bool, default True
Try to find better dtype for elementwise function results. If
False, leave as dtype=object.
args : tuple
Positional arguments passed to func after the series value.
**kwds
Additional keyword arguments passed to func.
Returns
-------
Series or DataFrame
If func returns a Series object the result will be a DataFrame.
See Also
--------
Series.map: For element-wise operations.
Series.agg: Only perform aggregating type operations.
Series.transform: Only perform transforming type operations.
Examples
--------
Create a series with typical summer temperatures for each city.
>>> s = pd.Series([20, 21, 12],
... index=['London', 'New York', 'Helsinki'])
>>> s
London 20
New York 21
Helsinki 12
dtype: int64
Square the values by defining a function and passing it as an
argument to ``apply()``.
>>> def square(x):
... return x ** 2
>>> s.apply(square)
London 400
New York 441
Helsinki 144
dtype: int64
Square the values by passing an anonymous function as an
argument to ``apply()``.
>>> s.apply(lambda x: x ** 2)
London 400
New York 441
Helsinki 144
dtype: int64
Define a custom function that needs additional positional
arguments and pass these additional arguments using the
``args`` keyword.
>>> def subtract_custom_value(x, custom_value):
... return x - custom_value
>>> s.apply(subtract_custom_value, args=(5,))
London 15
New York 16
Helsinki 7
dtype: int64
Define a custom function that takes keyword arguments
and pass these arguments to ``apply``.
>>> def add_custom_values(x, **kwargs):
... for month in kwargs:
... x += kwargs[month]
... return x
>>> s.apply(add_custom_values, june=30, july=20, august=25)
London 95
New York 96
Helsinki 87
dtype: int64
Use a function from the Numpy library.
>>> s.apply(np.log)
London 2.995732
New York 3.044522
Helsinki 2.484907
dtype: float64
"""
if len(self) == 0:
return self._constructor(dtype=self.dtype, index=self.index).__finalize__(
self, method="apply"
)
# dispatch to agg
if isinstance(func, (list, dict)):
return self.aggregate(func, *args, **kwds)
# if we are a string, try to dispatch
if isinstance(func, str):
return self._try_aggregate_string_function(func, *args, **kwds)
# handle ufuncs and lambdas
if kwds or args and not isinstance(func, np.ufunc):
def f(x):
return func(x, *args, **kwds)
else:
f = func
with np.errstate(all="ignore"):
if isinstance(f, np.ufunc):
return f(self)
# row-wise access
if is_extension_array_dtype(self.dtype) and hasattr(self._values, "map"):
# GH#23179 some EAs do not have `map`
mapped = self._values.map(f)
else:
values = self.astype(object)._values
mapped = lib.map_infer(values, f, convert=convert_dtype)
if len(mapped) and isinstance(mapped[0], Series):
# GH 25959 use pd.array instead of tolist
# so extension arrays can be used
return self._constructor_expanddim(pd.array(mapped), index=self.index)
else:
return self._constructor(mapped, index=self.index).__finalize__(
self, method="apply"
)
def _reduce(
self, op, name, axis=0, skipna=True, numeric_only=None, filter_type=None, **kwds
):
"""
Perform a reduction operation.
If we have an ndarray as a value, then simply perform the operation,
otherwise delegate to the object.
"""
delegate = self._values
if axis is not None:
self._get_axis_number(axis)
if isinstance(delegate, ExtensionArray):
# dispatch to ExtensionArray interface
return delegate._reduce(name, skipna=skipna, **kwds)
else:
# dispatch to numpy arrays
if numeric_only:
raise NotImplementedError(
f"Series.{name} does not implement numeric_only."
)
with np.errstate(all="ignore"):
return op(delegate, skipna=skipna, **kwds)
def _reindex_indexer(self, new_index, indexer, copy):
if indexer is None:
if copy:
return self.copy()
return self
new_values = algorithms.take_1d(
self._values, indexer, allow_fill=True, fill_value=None
)
return self._constructor(new_values, index=new_index)
def _needs_reindex_multi(self, axes, method, level):
"""
Check if we do need a multi reindex; this is for compat with
higher dims.
"""
return False
@doc(NDFrame.align, **_shared_doc_kwargs)
def align(
self,
other,
join="outer",
axis=None,
level=None,
copy=True,
fill_value=None,
method=None,
limit=None,
fill_axis=0,
broadcast_axis=None,
):
return super().align(
other,
join=join,
axis=axis,
level=level,
copy=copy,
fill_value=fill_value,
method=method,
limit=limit,
fill_axis=fill_axis,
broadcast_axis=broadcast_axis,
)
def rename(
self,
index=None,
*,
axis=None,
copy=True,
inplace=False,
level=None,
errors="ignore",
):
"""
Alter Series index labels or name.
Function / dict values must be unique (1-to-1). Labels not contained in
a dict / Series will be left as-is. Extra labels listed don't throw an
error.
Alternatively, change ``Series.name`` with a scalar value.
See the :ref:`user guide <basics.rename>` for more.
Parameters
----------
axis : {0 or "index"}
Unused. Accepted for compatibility with DataFrame method only.
index : scalar, hashable sequence, dict-like or function, optional
Functions or dict-like are transformations to apply to
the index.
Scalar or hashable sequence-like will alter the ``Series.name``
attribute.
**kwargs
Additional keyword arguments passed to the function. Only the
"inplace" keyword is used.
Returns
-------
Series
Series with index labels or name altered.
See Also
--------
DataFrame.rename : Corresponding DataFrame method.
Series.rename_axis : Set the name of the axis.
Examples
--------
>>> s = pd.Series([1, 2, 3])
>>> s
0 1
1 2
2 3
dtype: int64
>>> s.rename("my_name") # scalar, changes Series.name
0 1
1 2
2 3
Name: my_name, dtype: int64
>>> s.rename(lambda x: x ** 2) # function, changes labels
0 1
1 2
4 3
dtype: int64
>>> s.rename({1: 3, 2: 5}) # mapping, changes labels
0 1
3 2
5 3
dtype: int64
"""
if callable(index) or is_dict_like(index):
return super().rename(
index, copy=copy, inplace=inplace, level=level, errors=errors
)
else:
return self._set_name(index, inplace=inplace)
@Appender(
"""
Examples
--------
>>> s = pd.Series([1, 2, 3])
>>> s
0 1
1 2
2 3
dtype: int64
>>> s.set_axis(['a', 'b', 'c'], axis=0)
a 1
b 2
c 3
dtype: int64
"""
)
@Substitution(
**_shared_doc_kwargs,
extended_summary_sub="",
axis_description_sub="",
see_also_sub="",
)
@Appender(generic.NDFrame.set_axis.__doc__)
def set_axis(self, labels, axis: Axis = 0, inplace: bool = False):
return super().set_axis(labels, axis=axis, inplace=inplace)
@Substitution(**_shared_doc_kwargs)
@Appender(generic.NDFrame.reindex.__doc__)
def reindex(self, index=None, **kwargs):
return super().reindex(index=index, **kwargs)
def drop(
self,
labels=None,
axis=0,
index=None,
columns=None,
level=None,
inplace=False,
errors="raise",
) -> "Series":
"""
Return Series with specified index labels removed.
Remove elements of a Series based on specifying the index labels.
When using a multi-index, labels on different levels can be removed
by specifying the level.
Parameters
----------
labels : single label or list-like
Index labels to drop.
axis : 0, default 0
Redundant for application on Series.
index : single label or list-like
Redundant for application on Series, but 'index' can be used instead
of 'labels'.
columns : single label or list-like
No change is made to the Series; use 'index' or 'labels' instead.
level : int or level name, optional
For MultiIndex, level for which the labels will be removed.
inplace : bool, default False
If True, do operation inplace and return None.
errors : {'ignore', 'raise'}, default 'raise'
If 'ignore', suppress error and only existing labels are dropped.
Returns
-------
Series
Series with specified index labels removed.
Raises
------
KeyError
If none of the labels are found in the index.
See Also
--------
Series.reindex : Return only specified index labels of Series.
Series.dropna : Return series without null values.
Series.drop_duplicates : Return Series with duplicate values removed.
DataFrame.drop : Drop specified labels from rows or columns.
Examples
--------
>>> s = pd.Series(data=np.arange(3), index=['A', 'B', 'C'])
>>> s
A 0
B 1
C 2
dtype: int64
Drop labels B en C
>>> s.drop(labels=['B', 'C'])
A 0
dtype: int64
Drop 2nd level label in MultiIndex Series
>>> midx = pd.MultiIndex(levels=[['lama', 'cow', 'falcon'],
... ['speed', 'weight', 'length']],
... codes=[[0, 0, 0, 1, 1, 1, 2, 2, 2],
... [0, 1, 2, 0, 1, 2, 0, 1, 2]])
>>> s = pd.Series([45, 200, 1.2, 30, 250, 1.5, 320, 1, 0.3],
... index=midx)
>>> s
lama speed 45.0
weight 200.0
length 1.2
cow speed 30.0
weight 250.0
length 1.5
falcon speed 320.0
weight 1.0
length 0.3
dtype: float64
>>> s.drop(labels='weight', level=1)
lama speed 45.0
length 1.2
cow speed 30.0
length 1.5
falcon speed 320.0
length 0.3
dtype: float64
"""
return super().drop(
labels=labels,
axis=axis,
index=index,
columns=columns,
level=level,
inplace=inplace,
errors=errors,
)
@doc(NDFrame.fillna, **_shared_doc_kwargs)
def fillna(
self,
value=None,
method=None,
axis=None,
inplace=False,
limit=None,
downcast=None,
) -> Optional["Series"]:
return super().fillna(
value=value,
method=method,
axis=axis,
inplace=inplace,
limit=limit,
downcast=downcast,
)
@doc(NDFrame.replace, **_shared_doc_kwargs)
def replace(
self,
to_replace=None,
value=None,
inplace=False,
limit=None,
regex=False,
method="pad",
):
return super().replace(
to_replace=to_replace,
value=value,
inplace=inplace,
limit=limit,
regex=regex,
method=method,
)
@doc(NDFrame.shift, **_shared_doc_kwargs)
def shift(self, periods=1, freq=None, axis=0, fill_value=None) -> "Series":
return super().shift(
periods=periods, freq=freq, axis=axis, fill_value=fill_value
)
def memory_usage(self, index=True, deep=False):
"""
Return the memory usage of the Series.
The memory usage can optionally include the contribution of
the index and of elements of `object` dtype.
Parameters
----------
index : bool, default True
Specifies whether to include the memory usage of the Series index.
deep : bool, default False
If True, introspect the data deeply by interrogating
`object` dtypes for system-level memory consumption, and include
it in the returned value.
Returns
-------
int
Bytes of memory consumed.
See Also
--------
numpy.ndarray.nbytes : Total bytes consumed by the elements of the
array.
DataFrame.memory_usage : Bytes consumed by a DataFrame.
Examples
--------
>>> s = pd.Series(range(3))
>>> s.memory_usage()
152
Not including the index gives the size of the rest of the data, which
is necessarily smaller:
>>> s.memory_usage(index=False)
24
The memory footprint of `object` values is ignored by default:
>>> s = pd.Series(["a", "b"])
>>> s.values
array(['a', 'b'], dtype=object)
>>> s.memory_usage()
144
>>> s.memory_usage(deep=True)
260
"""
v = super().memory_usage(deep=deep)
if index:
v += self.index.memory_usage(deep=deep)
return v
def isin(self, values) -> "Series":
"""
Check whether `values` are contained in Series.
Return a boolean Series showing whether each element in the Series
matches an element in the passed sequence of `values` exactly.
Parameters
----------
values : set or list-like
The sequence of values to test. Passing in a single string will
raise a ``TypeError``. Instead, turn a single string into a
list of one element.
Returns
-------
Series
Series of booleans indicating if each element is in values.
Raises
------
TypeError
* If `values` is a string
See Also
--------
DataFrame.isin : Equivalent method on DataFrame.
Examples
--------
>>> s = pd.Series(['lama', 'cow', 'lama', 'beetle', 'lama',
... 'hippo'], name='animal')
>>> s.isin(['cow', 'lama'])
0 True
1 True
2 True
3 False
4 True
5 False
Name: animal, dtype: bool
Passing a single string as ``s.isin('lama')`` will raise an error. Use
a list of one element instead:
>>> s.isin(['lama'])
0 True
1 False
2 True
3 False
4 True
5 False
Name: animal, dtype: bool
"""
result = algorithms.isin(self, values)
return self._constructor(result, index=self.index).__finalize__(
self, method="isin"
)
def between(self, left, right, inclusive=True) -> "Series":
"""
Return boolean Series equivalent to left <= series <= right.
This function returns a boolean vector containing `True` wherever the
corresponding Series element is between the boundary values `left` and
`right`. NA values are treated as `False`.
Parameters
----------
left : scalar or list-like
Left boundary.
right : scalar or list-like
Right boundary.
inclusive : bool, default True
Include boundaries.
Returns
-------
Series
Series representing whether each element is between left and
right (inclusive).
See Also
--------
Series.gt : Greater than of series and other.
Series.lt : Less than of series and other.
Notes
-----
This function is equivalent to ``(left <= ser) & (ser <= right)``
Examples
--------
>>> s = pd.Series([2, 0, 4, 8, np.nan])
Boundary values are included by default:
>>> s.between(1, 4)
0 True
1 False
2 True
3 False
4 False
dtype: bool
With `inclusive` set to ``False`` boundary values are excluded:
>>> s.between(1, 4, inclusive=False)
0 True
1 False
2 False
3 False
4 False
dtype: bool
`left` and `right` can be any scalar value:
>>> s = pd.Series(['Alice', 'Bob', 'Carol', 'Eve'])
>>> s.between('Anna', 'Daniel')
0 False
1 True
2 True
3 False
dtype: bool
"""
if inclusive:
lmask = self >= left
rmask = self <= right
else:
lmask = self > left
rmask = self < right
return lmask & rmask
# ----------------------------------------------------------------------
# Convert to types that support pd.NA
def _convert_dtypes(
self,
infer_objects: bool = True,
convert_string: bool = True,
convert_integer: bool = True,
convert_boolean: bool = True,
) -> "Series":
input_series = self
if infer_objects:
input_series = input_series.infer_objects()
if is_object_dtype(input_series):
input_series = input_series.copy()
if convert_string or convert_integer or convert_boolean:
inferred_dtype = convert_dtypes(
input_series._values, convert_string, convert_integer, convert_boolean
)
try:
result = input_series.astype(inferred_dtype)
except TypeError:
result = input_series.copy()
else:
result = input_series.copy()
return result
@Appender(generic._shared_docs["isna"] % _shared_doc_kwargs)
def isna(self) -> "Series":
return super().isna()
@Appender(generic._shared_docs["isna"] % _shared_doc_kwargs)
def isnull(self) -> "Series":
return super().isnull()
@Appender(generic._shared_docs["notna"] % _shared_doc_kwargs)
def notna(self) -> "Series":
return super().notna()
@Appender(generic._shared_docs["notna"] % _shared_doc_kwargs)
def notnull(self) -> "Series":
return super().notnull()
def dropna(self, axis=0, inplace=False, how=None):
"""
Return a new Series with missing values removed.
See the :ref:`User Guide <missing_data>` for more on which values are
considered missing, and how to work with missing data.
Parameters
----------
axis : {0 or 'index'}, default 0
There is only one axis to drop values from.
inplace : bool, default False
If True, do operation inplace and return None.
how : str, optional
Not in use. Kept for compatibility.
Returns
-------
Series
Series with NA entries dropped from it.
See Also
--------
Series.isna: Indicate missing values.
Series.notna : Indicate existing (non-missing) values.
Series.fillna : Replace missing values.
DataFrame.dropna : Drop rows or columns which contain NA values.
Index.dropna : Drop missing indices.
Examples
--------
>>> ser = pd.Series([1., 2., np.nan])
>>> ser
0 1.0
1 2.0
2 NaN
dtype: float64
Drop NA values from a Series.
>>> ser.dropna()
0 1.0
1 2.0
dtype: float64
Keep the Series with valid entries in the same variable.
>>> ser.dropna(inplace=True)
>>> ser
0 1.0
1 2.0
dtype: float64
Empty strings are not considered NA values. ``None`` is considered an
NA value.
>>> ser = pd.Series([np.NaN, 2, pd.NaT, '', None, 'I stay'])
>>> ser
0 NaN
1 2
2 NaT
3
4 None
5 I stay
dtype: object
>>> ser.dropna()
1 2
3
5 I stay
dtype: object
"""
inplace = validate_bool_kwarg(inplace, "inplace")
# Validate the axis parameter
self._get_axis_number(axis or 0)
if self._can_hold_na:
result = remove_na_arraylike(self)
if inplace:
self._update_inplace(result)
else:
return result
else:
if inplace:
# do nothing
pass
else:
return self.copy()
# ----------------------------------------------------------------------
# Time series-oriented methods
def to_timestamp(self, freq=None, how="start", copy=True) -> "Series":
"""
Cast to DatetimeIndex of Timestamps, at *beginning* of period.
Parameters
----------
freq : str, default frequency of PeriodIndex
Desired frequency.
how : {'s', 'e', 'start', 'end'}
Convention for converting period to timestamp; start of period
vs. end.
copy : bool, default True
Whether or not to return a copy.
Returns
-------
Series with DatetimeIndex
"""
new_values = self._values
if copy:
new_values = new_values.copy()
assert isinstance(self.index, (ABCDatetimeIndex, ABCPeriodIndex))
new_index = self.index.to_timestamp(freq=freq, how=how)
return self._constructor(new_values, index=new_index).__finalize__(
self, method="to_timestamp"
)
def to_period(self, freq=None, copy=True) -> "Series":
"""
Convert Series from DatetimeIndex to PeriodIndex with desired
frequency (inferred from index if not passed).
Parameters
----------
freq : str, default None
Frequency associated with the PeriodIndex.
copy : bool, default True
Whether or not to return a copy.
Returns
-------
Series
Series with index converted to PeriodIndex.
"""
new_values = self._values
if copy:
new_values = new_values.copy()
assert isinstance(self.index, ABCDatetimeIndex)
new_index = self.index.to_period(freq=freq)
return self._constructor(new_values, index=new_index).__finalize__(
self, method="to_period"
)
# ----------------------------------------------------------------------
# Add index
_AXIS_ORDERS = ["index"]
_AXIS_NUMBERS = {"index": 0}
_AXIS_NAMES = {0: "index"}
_AXIS_REVERSED = False
_AXIS_LEN = len(_AXIS_ORDERS)
_info_axis_number = 0
_info_axis_name = "index"
index: "Index" = properties.AxisProperty(
axis=0, doc="The index (axis labels) of the Series."
)
# ----------------------------------------------------------------------
# Accessor Methods
# ----------------------------------------------------------------------
str = CachedAccessor("str", StringMethods)
dt = CachedAccessor("dt", CombinedDatetimelikeProperties)
cat = CachedAccessor("cat", CategoricalAccessor)
plot = CachedAccessor("plot", pandas.plotting.PlotAccessor)
sparse = CachedAccessor("sparse", SparseAccessor)
# ----------------------------------------------------------------------
# Add plotting methods to Series
hist = pandas.plotting.hist_series
Series._add_numeric_operations()
Series._add_series_or_dataframe_operations()
# Add arithmetic!
ops.add_flex_arithmetic_methods(Series)
ops.add_special_arithmetic_methods(Series)
"""
Data structure for 1-dimensional cross-sectional and time series data
"""
from io import StringIO
from shutil import get_terminal_size
from textwrap import dedent
from typing import (
IO,
TYPE_CHECKING,
Any,
Callable,
Iterable,
List,
Optional,
Tuple,
Type,
Union,
)
import warnings
import numpy as np
from pandas._config import get_option
from pandas._libs import lib, properties, reshape, tslibs
from pandas._typing import ArrayLike, Axis, DtypeObj, Label
from pandas.compat.numpy import function as nv
from pandas.util._decorators import Appender, Substitution, doc
from pandas.util._validators import validate_bool_kwarg, validate_percentile
from pandas.core.dtypes.cast import (
convert_dtypes,
maybe_cast_to_extension_array,
validate_numeric_casting,
)
from pandas.core.dtypes.common import (
ensure_platform_int,
is_bool,
is_categorical_dtype,
is_dict_like,
is_extension_array_dtype,
is_integer,
is_iterator,
is_list_like,
is_object_dtype,
is_scalar,
)
from pandas.core.dtypes.generic import (
ABCDataFrame,
ABCDatetimeIndex,
ABCMultiIndex,
ABCPeriodIndex,
ABCSeries,
)
from pandas.core.dtypes.inference import is_hashable
from pandas.core.dtypes.missing import (
isna,
na_value_for_dtype,
notna,
remove_na_arraylike,
)
import pandas as pd
from pandas.core import algorithms, base, generic, nanops, ops
from pandas.core.accessor import CachedAccessor
from pandas.core.arrays import ExtensionArray
from pandas.core.arrays.categorical import CategoricalAccessor
from pandas.core.arrays.sparse import SparseAccessor
import pandas.core.common as com
from pandas.core.construction import (
create_series_with_explicit_dtype,
extract_array,
is_empty_data,
sanitize_array,
)
from pandas.core.generic import NDFrame
from pandas.core.indexers import unpack_1tuple
from pandas.core.indexes.accessors import CombinedDatetimelikeProperties
from pandas.core.indexes.api import (
Float64Index,
Index,
InvalidIndexError,
MultiIndex,
ensure_index,
)
import pandas.core.indexes.base as ibase
from pandas.core.indexes.datetimes import DatetimeIndex
from pandas.core.indexes.period import PeriodIndex
from pandas.core.indexes.timedeltas import TimedeltaIndex
from pandas.core.indexing import check_bool_indexer
from pandas.core.internals import SingleBlockManager
from pandas.core.strings import StringMethods
from pandas.core.tools.datetimes import to_datetime
import pandas.io.formats.format as fmt
import pandas.plotting
if TYPE_CHECKING:
from pandas.core.frame import DataFrame
from pandas.core.groupby.generic import SeriesGroupBy
__all__ = ["Series"]
_shared_doc_kwargs = dict(
axes="index",
klass="Series",
axes_single_arg="{0 or 'index'}",
axis="""axis : {0 or 'index'}
Parameter needed for compatibility with DataFrame.""",
inplace="""inplace : boolean, default False
If True, performs operation inplace and returns None.""",
unique="np.ndarray",
duplicated="Series",
optional_by="",
optional_mapper="",
optional_labels="",
optional_axis="",
versionadded_to_excel="\n .. versionadded:: 0.20.0\n",
)
def _coerce_method(converter):
"""
Install the scalar coercion methods.
"""
def wrapper(self):
if len(self) == 1:
return converter(self.iloc[0])
raise TypeError(f"cannot convert the series to {converter}")
wrapper.__name__ = f"__{converter.__name__}__"
return wrapper
# ----------------------------------------------------------------------
# Series class
class Series(base.IndexOpsMixin, generic.NDFrame):
"""
One-dimensional ndarray with axis labels (including time series).
Labels need not be unique but must be a hashable type. The object
supports both integer- and label-based indexing and provides a host of
methods for performing operations involving the index. Statistical
methods from ndarray have been overridden to automatically exclude
missing data (currently represented as NaN).
Operations between Series (+, -, /, *, **) align values based on their
associated index values-- they need not be the same length. The result
index will be the sorted union of the two indexes.
Parameters
----------
data : array-like, Iterable, dict, or scalar value
Contains data stored in Series.
.. versionchanged:: 0.23.0
If data is a dict, argument order is maintained for Python 3.6
and later.
index : array-like or Index (1d)
Values must be hashable and have the same length as `data`.
Non-unique index values are allowed. Will default to
RangeIndex (0, 1, 2, ..., n) if not provided. If both a dict and index
sequence are used, the index will override the keys found in the
dict.
dtype : str, numpy.dtype, or ExtensionDtype, optional
Data type for the output Series. If not specified, this will be
inferred from `data`.
See the :ref:`user guide <basics.dtypes>` for more usages.
name : str, optional
The name to give to the Series.
copy : bool, default False
Copy input data.
"""
_typ = "series"
_name: Label
_metadata: List[str] = ["name"]
_internal_names_set = {"index"} | generic.NDFrame._internal_names_set
_accessors = {"dt", "cat", "str", "sparse"}
_deprecations = (
base.IndexOpsMixin._deprecations
| generic.NDFrame._deprecations
| frozenset(["compress", "ptp"])
)
# Override cache_readonly bc Series is mutable
hasnans = property(
base.IndexOpsMixin.hasnans.func, doc=base.IndexOpsMixin.hasnans.__doc__
)
_mgr: SingleBlockManager
div: Callable[["Series", Any], "Series"]
rdiv: Callable[["Series", Any], "Series"]
# ----------------------------------------------------------------------
# Constructors
def __init__(
self, data=None, index=None, dtype=None, name=None, copy=False, fastpath=False
):
if (
isinstance(data, SingleBlockManager)
and index is None
and dtype is None
and copy is False
):
# GH#33357 called with just the SingleBlockManager
NDFrame.__init__(self, data)
self.name = name
return
# we are called internally, so short-circuit
if fastpath:
# data is an ndarray, index is defined
if not isinstance(data, SingleBlockManager):
data = SingleBlockManager.from_array(data, index)
if copy:
data = data.copy()
if index is None:
index = data.index
else:
name = ibase.maybe_extract_name(name, data, type(self))
if is_empty_data(data) and dtype is None:
# gh-17261
warnings.warn(
"The default dtype for empty Series will be 'object' instead "
"of 'float64' in a future version. Specify a dtype explicitly "
"to silence this warning.",
DeprecationWarning,
stacklevel=2,
)
# uncomment the line below when removing the DeprecationWarning
# dtype = np.dtype(object)
if index is not None:
index = ensure_index(index)
if data is None:
data = {}
if dtype is not None:
dtype = self._validate_dtype(dtype)
if isinstance(data, MultiIndex):
raise NotImplementedError(
"initializing a Series from a MultiIndex is not supported"
)
elif isinstance(data, Index):
if dtype is not None:
# astype copies
data = data.astype(dtype)
else:
# need to copy to avoid aliasing issues
data = data._values.copy()
if isinstance(data, ABCDatetimeIndex) and data.tz is not None:
# GH#24096 need copy to be deep for datetime64tz case
# TODO: See if we can avoid these copies
data = data._values.copy(deep=True)
copy = False
elif isinstance(data, np.ndarray):
if len(data.dtype):
# GH#13296 we are dealing with a compound dtype, which
# should be treated as 2D
raise ValueError(
"Cannot construct a Series from an ndarray with "
"compound dtype. Use DataFrame instead."
)
pass
elif isinstance(data, ABCSeries):
if index is None:
index = data.index
else:
data = data.reindex(index, copy=copy)
data = data._mgr
elif is_dict_like(data):
data, index = self._init_dict(data, index, dtype)
dtype = None
copy = False
elif isinstance(data, SingleBlockManager):
if index is None:
index = data.index
elif not data.index.equals(index) or copy:
# GH#19275 SingleBlockManager input should only be called
# internally
raise AssertionError(
"Cannot pass both SingleBlockManager "
"`data` argument and a different "
"`index` argument. `copy` must be False."
)
elif is_extension_array_dtype(data):
pass
elif isinstance(data, (set, frozenset)):
raise TypeError(f"'{type(data).__name__}' type is unordered")
else:
data = com.maybe_iterable_to_list(data)
if index is None:
if not is_list_like(data):
data = [data]
index = ibase.default_index(len(data))
elif is_list_like(data):
# a scalar numpy array is list-like but doesn't
# have a proper length
try:
if len(index) != len(data):
raise ValueError(
f"Length of passed values is {len(data)}, "
f"index implies {len(index)}."
)
except TypeError:
pass
# create/copy the manager
if isinstance(data, SingleBlockManager):
if dtype is not None:
data = data.astype(dtype=dtype, errors="ignore", copy=copy)
elif copy:
data = data.copy()
else:
data = sanitize_array(data, index, dtype, copy, raise_cast_failure=True)
data = SingleBlockManager.from_array(data, index)
generic.NDFrame.__init__(self, data)
self.name = name
self._set_axis(0, index, fastpath=True)
def _init_dict(self, data, index=None, dtype=None):
"""
Derive the "_mgr" and "index" attributes of a new Series from a
dictionary input.
Parameters
----------
data : dict or dict-like
Data used to populate the new Series.
index : Index or index-like, default None
Index for the new Series: if None, use dict keys.
dtype : dtype, default None
The dtype for the new Series: if None, infer from data.
Returns
-------
_data : BlockManager for the new Series
index : index for the new Series
"""
# Looking for NaN in dict doesn't work ({np.nan : 1}[float('nan')]
# raises KeyError), so we iterate the entire dict, and align
if data:
keys, values = zip(*data.items())
values = list(values)
elif index is not None:
# fastpath for Series(data=None). Just use broadcasting a scalar
# instead of reindexing.
values = na_value_for_dtype(dtype)
keys = index
else:
keys, values = [], []
# Input is now list-like, so rely on "standard" construction:
# TODO: passing np.float64 to not break anything yet. See GH-17261
s = create_series_with_explicit_dtype(
values, index=keys, dtype=dtype, dtype_if_empty=np.float64
)
# Now we just make sure the order is respected, if any
if data and index is not None:
s = s.reindex(index, copy=False)
return s._mgr, s.index
# ----------------------------------------------------------------------
@property
def _constructor(self) -> Type["Series"]:
return Series
@property
def _constructor_expanddim(self) -> Type["DataFrame"]:
from pandas.core.frame import DataFrame
return DataFrame
# types
@property
def _can_hold_na(self):
return self._mgr._can_hold_na
_index = None
def _set_axis(self, axis: int, labels, fastpath: bool = False) -> None:
"""
Override generic, we want to set the _typ here.
This is called from the cython code when we set the `index` attribute
directly, e.g. `series.index = [1, 2, 3]`.
"""
if not fastpath:
labels = ensure_index(labels)
is_all_dates = labels.is_all_dates
if is_all_dates:
if not isinstance(labels, (DatetimeIndex, PeriodIndex, TimedeltaIndex)):
try:
labels = DatetimeIndex(labels)
# need to set here because we changed the index
if fastpath:
self._mgr.set_axis(axis, labels)
except (tslibs.OutOfBoundsDatetime, ValueError):
# labels may exceeds datetime bounds,
# or not be a DatetimeIndex
pass
object.__setattr__(self, "_index", labels)
if not fastpath:
# The ensure_index call above ensures we have an Index object
self._mgr.set_axis(axis, labels)
# ndarray compatibility
@property
def dtype(self) -> DtypeObj:
"""
Return the dtype object of the underlying data.
"""
return self._mgr.dtype
@property
def dtypes(self) -> DtypeObj:
"""
Return the dtype object of the underlying data.
"""
# DataFrame compatibility
return self.dtype
@property
def name(self) -> Label:
"""
Return the name of the Series.
The name of a Series becomes its index or column name if it is used
to form a DataFrame. It is also used whenever displaying the Series
using the interpreter.
Returns
-------
label (hashable object)
The name of the Series, also the column name if part of a DataFrame.
See Also
--------
Series.rename : Sets the Series name when given a scalar input.
Index.name : Corresponding Index property.
Examples
--------
The Series name can be set initially when calling the constructor.
>>> s = pd.Series([1, 2, 3], dtype=np.int64, name='Numbers')
>>> s
0 1
1 2
2 3
Name: Numbers, dtype: int64
>>> s.name = "Integers"
>>> s
0 1
1 2
2 3
Name: Integers, dtype: int64
The name of a Series within a DataFrame is its column name.
>>> df = pd.DataFrame([[1, 2], [3, 4], [5, 6]],
... columns=["Odd Numbers", "Even Numbers"])
>>> df
Odd Numbers Even Numbers
0 1 2
1 3 4
2 5 6
>>> df["Even Numbers"].name
'Even Numbers'
"""
return self._name
@name.setter
def name(self, value: Label) -> None:
if not is_hashable(value):
raise TypeError("Series.name must be a hashable type")
object.__setattr__(self, "_name", value)
@property
def values(self):
"""
Return Series as ndarray or ndarray-like depending on the dtype.
.. warning::
We recommend using :attr:`Series.array` or
:meth:`Series.to_numpy`, depending on whether you need
a reference to the underlying data or a NumPy array.
Returns
-------
numpy.ndarray or ndarray-like
See Also
--------
Series.array : Reference to the underlying data.
Series.to_numpy : A NumPy array representing the underlying data.
Examples
--------
>>> pd.Series([1, 2, 3]).values
array([1, 2, 3])
>>> pd.Series(list('aabc')).values
array(['a', 'a', 'b', 'c'], dtype=object)
>>> pd.Series(list('aabc')).astype('category').values
[a, a, b, c]
Categories (3, object): [a, b, c]
Timezone aware datetime data is converted to UTC:
>>> pd.Series(pd.date_range('20130101', periods=3,
... tz='US/Eastern')).values
array(['2013-01-01T05:00:00.000000000',
'2013-01-02T05:00:00.000000000',
'2013-01-03T05:00:00.000000000'], dtype='datetime64[ns]')
"""
return self._mgr.external_values()
@property
def _values(self):
"""
Return the internal repr of this data (defined by Block.interval_values).
This are the values as stored in the Block (ndarray or ExtensionArray
depending on the Block class), with datetime64[ns] and timedelta64[ns]
wrapped in ExtensionArrays to match Index._values behavior.
Differs from the public ``.values`` for certain data types, because of
historical backwards compatibility of the public attribute (e.g. period
returns object ndarray and datetimetz a datetime64[ns] ndarray for
``.values`` while it returns an ExtensionArray for ``._values`` in those
cases).
Differs from ``.array`` in that this still returns the numpy array if
the Block is backed by a numpy array (except for datetime64 and
timedelta64 dtypes), while ``.array`` ensures to always return an
ExtensionArray.
Overview:
dtype | values | _values | array |
----------- | ------------- | ------------- | ------------- |
Numeric | ndarray | ndarray | PandasArray |
Category | Categorical | Categorical | Categorical |
dt64[ns] | ndarray[M8ns] | DatetimeArray | DatetimeArray |
dt64[ns tz] | ndarray[M8ns] | DatetimeArray | DatetimeArray |
td64[ns] | ndarray[m8ns] | TimedeltaArray| ndarray[m8ns] |
Period | ndarray[obj] | PeriodArray | PeriodArray |
Nullable | EA | EA | EA |
"""
return self._mgr.internal_values()
@Appender(base.IndexOpsMixin.array.__doc__) # type: ignore
@property
def array(self) -> ExtensionArray:
return self._mgr._block.array_values()
# ops
def ravel(self, order="C"):
"""
Return the flattened underlying data as an ndarray.
Returns
-------
numpy.ndarray or ndarray-like
Flattened data of the Series.
See Also
--------
numpy.ndarray.ravel : Return a flattened array.
"""
return self._values.ravel(order=order)
def __len__(self) -> int:
"""
Return the length of the Series.
"""
return len(self._mgr)
def view(self, dtype=None) -> "Series":
"""
Create a new view of the Series.
This function will return a new Series with a view of the same
underlying values in memory, optionally reinterpreted with a new data
type. The new data type must preserve the same size in bytes as to not
cause index misalignment.
Parameters
----------
dtype : data type
Data type object or one of their string representations.
Returns
-------
Series
A new Series object as a view of the same data in memory.
See Also
--------
numpy.ndarray.view : Equivalent numpy function to create a new view of
the same data in memory.
Notes
-----
Series are instantiated with ``dtype=float64`` by default. While
``numpy.ndarray.view()`` will return a view with the same data type as
the original array, ``Series.view()`` (without specified dtype)
will try using ``float64`` and may fail if the original data type size
in bytes is not the same.
Examples
--------
>>> s = pd.Series([-2, -1, 0, 1, 2], dtype='int8')
>>> s
0 -2
1 -1
2 0
3 1
4 2
dtype: int8
The 8 bit signed integer representation of `-1` is `0b11111111`, but
the same bytes represent 255 if read as an 8 bit unsigned integer:
>>> us = s.view('uint8')
>>> us
0 254
1 255
2 0
3 1
4 2
dtype: uint8
The views share the same underlying values:
>>> us[0] = 128
>>> s
0 -128
1 -1
2 0
3 1
4 2
dtype: int8
"""
return self._constructor(
self._values.view(dtype), index=self.index
).__finalize__(self, method="view")
# ----------------------------------------------------------------------
# NDArray Compat
_HANDLED_TYPES = (Index, ExtensionArray, np.ndarray)
def __array_ufunc__(
self, ufunc: Callable, method: str, *inputs: Any, **kwargs: Any
):
# TODO: handle DataFrame
cls = type(self)
# for binary ops, use our custom dunder methods
result = ops.maybe_dispatch_ufunc_to_dunder_op(
self, ufunc, method, *inputs, **kwargs
)
if result is not NotImplemented:
return result
# Determine if we should defer.
no_defer = (np.ndarray.__array_ufunc__, cls.__array_ufunc__)
for item in inputs:
higher_priority = (
hasattr(item, "__array_priority__")
and item.__array_priority__ > self.__array_priority__
)
has_array_ufunc = (
hasattr(item, "__array_ufunc__")
and type(item).__array_ufunc__ not in no_defer
and not isinstance(item, self._HANDLED_TYPES)
)
if higher_priority or has_array_ufunc:
return NotImplemented
# align all the inputs.
names = [getattr(x, "name") for x in inputs if hasattr(x, "name")]
types = tuple(type(x) for x in inputs)
# TODO: dataframe
alignable = [x for x, t in zip(inputs, types) if issubclass(t, Series)]
if len(alignable) > 1:
# This triggers alignment.
# At the moment, there aren't any ufuncs with more than two inputs
# so this ends up just being x1.index | x2.index, but we write
# it to handle *args.
index = alignable[0].index
for s in alignable[1:]:
index |= s.index
inputs = tuple(
x.reindex(index) if issubclass(t, Series) else x
for x, t in zip(inputs, types)
)
else:
index = self.index
inputs = tuple(extract_array(x, extract_numpy=True) for x in inputs)
result = getattr(ufunc, method)(*inputs, **kwargs)
name = names[0] if len(set(names)) == 1 else None
def construct_return(result):
if lib.is_scalar(result):
return result
elif result.ndim > 1:
# e.g. np.subtract.outer
if method == "outer":
# GH#27198
raise NotImplementedError
return result
return self._constructor(result, index=index, name=name, copy=False)
if type(result) is tuple:
# multiple return values
return tuple(construct_return(x) for x in result)
elif method == "at":
# no return value
return None
else:
return construct_return(result)
def __array__(self, dtype=None) -> np.ndarray:
"""
Return the values as a NumPy array.
Users should not call this directly. Rather, it is invoked by
:func:`numpy.array` and :func:`numpy.asarray`.
Parameters
----------
dtype : str or numpy.dtype, optional
The dtype to use for the resulting NumPy array. By default,
the dtype is inferred from the data.
Returns
-------
numpy.ndarray
The values in the series converted to a :class:`numpy.ndarray`
with the specified `dtype`.
See Also
--------
array : Create a new array from data.
Series.array : Zero-copy view to the array backing the Series.
Series.to_numpy : Series method for similar behavior.
Examples
--------
>>> ser = pd.Series([1, 2, 3])
>>> np.asarray(ser)
array([1, 2, 3])
For timezone-aware data, the timezones may be retained with
``dtype='object'``
>>> tzser = pd.Series(pd.date_range('2000', periods=2, tz="CET"))
>>> np.asarray(tzser, dtype="object")
array([Timestamp('2000-01-01 00:00:00+0100', tz='CET', freq='D'),
Timestamp('2000-01-02 00:00:00+0100', tz='CET', freq='D')],
dtype=object)
Or the values may be localized to UTC and the tzinfo discarded with
``dtype='datetime64[ns]'``
>>> np.asarray(tzser, dtype="datetime64[ns]") # doctest: +ELLIPSIS
array(['1999-12-31T23:00:00.000000000', ...],
dtype='datetime64[ns]')
"""
return np.asarray(self.array, dtype)
# ----------------------------------------------------------------------
# Unary Methods
# coercion
__float__ = _coerce_method(float)
__long__ = _coerce_method(int)
__int__ = _coerce_method(int)
# ----------------------------------------------------------------------
# indexers
@property
def axes(self) -> List[Index]:
"""
Return a list of the row axis labels.
"""
return [self.index]
# ----------------------------------------------------------------------
# Indexing Methods
@Appender(generic.NDFrame.take.__doc__)
def take(self, indices, axis=0, is_copy=None, **kwargs) -> "Series":
if is_copy is not None:
warnings.warn(
"is_copy is deprecated and will be removed in a future version. "
"'take' always returns a copy, so there is no need to specify this.",
FutureWarning,
stacklevel=2,
)
nv.validate_take(tuple(), kwargs)
indices = ensure_platform_int(indices)
new_index = self.index.take(indices)
new_values = self._values.take(indices)
result = self._constructor(new_values, index=new_index, fastpath=True)
return result.__finalize__(self, method="take")
def _take_with_is_copy(self, indices, axis=0):
"""
Internal version of the `take` method that sets the `_is_copy`
attribute to keep track of the parent dataframe (using in indexing
for the SettingWithCopyWarning). For Series this does the same
as the public take (it never sets `_is_copy`).
See the docstring of `take` for full explanation of the parameters.
"""
return self.take(indices=indices, axis=axis)
def _ixs(self, i: int, axis: int = 0):
"""
Return the i-th value or values in the Series by location.
Parameters
----------
i : int
Returns
-------
scalar (int) or Series (slice, sequence)
"""
return self._values[i]
def _slice(self, slobj: slice, axis: int = 0) -> "Series":
# axis kwarg is retained for compat with NDFrame method
# _slice is *always* positional
return self._get_values(slobj)
def __getitem__(self, key):
key = com.apply_if_callable(key, self)
if key is Ellipsis:
return self
key_is_scalar = is_scalar(key)
if isinstance(key, (list, tuple)):
key = unpack_1tuple(key)
if is_integer(key) and self.index._should_fallback_to_positional():
return self._values[key]
elif key_is_scalar:
return self._get_value(key)
if (
isinstance(key, tuple)
and is_hashable(key)
and isinstance(self.index, MultiIndex)
):
# Otherwise index.get_value will raise InvalidIndexError
try:
result = self._get_value(key)
return result
except KeyError:
# We still have the corner case where this tuple is a key
# in the first level of our MultiIndex
return self._get_values_tuple(key)
if is_iterator(key):
key = list(key)
if com.is_bool_indexer(key):
key = check_bool_indexer(self.index, key)
key = np.asarray(key, dtype=bool)
return self._get_values(key)
return self._get_with(key)
def _get_with(self, key):
# other: fancy integer or otherwise
if isinstance(key, slice):
# _convert_slice_indexer to determin if this slice is positional
# or label based, and if the latter, convert to positional
slobj = self.index._convert_slice_indexer(key, kind="getitem")
return self._slice(slobj)
elif isinstance(key, ABCDataFrame):
raise TypeError(
"Indexing a Series with DataFrame is not "
"supported, use the appropriate DataFrame column"
)
elif isinstance(key, tuple):
return self._get_values_tuple(key)
elif not is_list_like(key):
# e.g. scalars that aren't recognized by lib.is_scalar, GH#32684
return self.loc[key]
if not isinstance(key, (list, np.ndarray, ExtensionArray, Series, Index)):
key = list(key)
if isinstance(key, Index):
key_type = key.inferred_type
else:
key_type = lib.infer_dtype(key, skipna=False)
# Note: The key_type == "boolean" case should be caught by the
# com.is_bool_indexer check in __getitem__
if key_type == "integer":
# We need to decide whether to treat this as a positional indexer
# (i.e. self.iloc) or label-based (i.e. self.loc)
if not self.index._should_fallback_to_positional():
return self.loc[key]
else:
return self.iloc[key]
# handle the dup indexing case GH#4246
return self.loc[key]
def _get_values_tuple(self, key):
# mpl hackaround
if com.any_none(*key):
# suppress warning from slicing the index with a 2d indexer.
# eventually we'll want Series itself to warn.
with warnings.catch_warnings():
warnings.filterwarnings(
"ignore", "Support for multi-dim", DeprecationWarning
)
return self._get_values(key)
if not isinstance(self.index, MultiIndex):
raise ValueError("Can only tuple-index with a MultiIndex")
# If key is contained, would have returned by now
indexer, new_index = self.index.get_loc_level(key)
return self._constructor(self._values[indexer], index=new_index).__finalize__(
self,
)
def _get_values(self, indexer):
try:
return self._constructor(self._mgr.get_slice(indexer)).__finalize__(self,)
except ValueError:
# mpl compat if we look up e.g. ser[:, np.newaxis];
# see tests.series.timeseries.test_mpl_compat_hack
return self._values[indexer]
def _get_value(self, label, takeable: bool = False):
"""
Quickly retrieve single value at passed index label.
Parameters
----------
label : object
takeable : interpret the index as indexers, default False
Returns
-------
scalar value
"""
if takeable:
return self._values[label]
# Similar to Index.get_value, but we do not fall back to positional
loc = self.index.get_loc(label)
return self.index._get_values_for_loc(self, loc, label)
def __setitem__(self, key, value):
key = com.apply_if_callable(key, self)
cacher_needs_updating = self._check_is_chained_assignment_possible()
if key is Ellipsis:
key = slice(None)
try:
self._set_with_engine(key, value)
except (KeyError, ValueError):
values = self._values
if is_integer(key) and not self.index.inferred_type == "integer":
# positional setter
values[key] = value
else:
# GH#12862 adding an new key to the Series
self.loc[key] = value
except TypeError as e:
if isinstance(key, tuple) and not isinstance(self.index, MultiIndex):
raise ValueError("Can only tuple-index with a MultiIndex") from e
if com.is_bool_indexer(key):
key = check_bool_indexer(self.index, key)
key = np.asarray(key, dtype=bool)
try:
self._where(~key, value, inplace=True)
except InvalidIndexError:
self.iloc[key] = value
return
else:
self._set_with(key, value)
if cacher_needs_updating:
self._maybe_update_cacher()
def _set_with_engine(self, key, value):
# fails with AttributeError for IntervalIndex
loc = self.index._engine.get_loc(key)
validate_numeric_casting(self.dtype, value)
self._values[loc] = value
def _set_with(self, key, value):
# other: fancy integer or otherwise
if isinstance(key, slice):
# extract_array so that if we set e.g. ser[-5:] = ser[:5]
# we get the first five values, and not 5 NaNs
indexer = self.index._convert_slice_indexer(key, kind="getitem")
self.iloc[indexer] = extract_array(value, extract_numpy=True)
else:
assert not isinstance(key, tuple)
if is_scalar(key):
key = [key]
if isinstance(key, Index):
key_type = key.inferred_type
key = key._values
else:
key_type = lib.infer_dtype(key, skipna=False)
# Note: key_type == "boolean" should not occur because that
# should be caught by the is_bool_indexer check in __setitem__
if key_type == "integer":
if not self.index._should_fallback_to_positional():
self.loc[key] = value
else:
self.iloc[key] = value
else:
self.loc[key] = value
def _set_value(self, label, value, takeable: bool = False):
"""
Quickly set single value at passed label.
If label is not contained, a new object is created with the label
placed at the end of the result index.
Parameters
----------
label : object
Partial indexing with MultiIndex not allowed.
value : object
Scalar value.
takeable : interpret the index as indexers, default False
"""
try:
if takeable:
self._values[label] = value
else:
loc = self.index.get_loc(label)
validate_numeric_casting(self.dtype, value)
self._values[loc] = value
except KeyError:
# set using a non-recursive method
self.loc[label] = value
# ----------------------------------------------------------------------
# Unsorted
@property
def _is_mixed_type(self):
return False
def repeat(self, repeats, axis=None) -> "Series":
"""
Repeat elements of a Series.
Returns a new Series where each element of the current Series
is repeated consecutively a given number of times.
Parameters
----------
repeats : int or array of ints
The number of repetitions for each element. This should be a
non-negative integer. Repeating 0 times will return an empty
Series.
axis : None
Must be ``None``. Has no effect but is accepted for compatibility
with numpy.
Returns
-------
Series
Newly created Series with repeated elements.
See Also
--------
Index.repeat : Equivalent function for Index.
numpy.repeat : Similar method for :class:`numpy.ndarray`.
Examples
--------
>>> s = pd.Series(['a', 'b', 'c'])
>>> s
0 a
1 b
2 c
dtype: object
>>> s.repeat(2)
0 a
0 a
1 b
1 b
2 c
2 c
dtype: object
>>> s.repeat([1, 2, 3])
0 a
1 b
1 b
2 c
2 c
2 c
dtype: object
"""
nv.validate_repeat(tuple(), dict(axis=axis))
new_index = self.index.repeat(repeats)
new_values = self._values.repeat(repeats)
return self._constructor(new_values, index=new_index).__finalize__(
self, method="repeat"
)
def reset_index(self, level=None, drop=False, name=None, inplace=False):
"""
Generate a new DataFrame or Series with the index reset.
This is useful when the index needs to be treated as a column, or
when the index is meaningless and needs to be reset to the default
before another operation.
Parameters
----------
level : int, str, tuple, or list, default optional
For a Series with a MultiIndex, only remove the specified levels
from the index. Removes all levels by default.
drop : bool, default False
Just reset the index, without inserting it as a column in
the new DataFrame.
name : object, optional
The name to use for the column containing the original Series
values. Uses ``self.name`` by default. This argument is ignored
when `drop` is True.
inplace : bool, default False
Modify the Series in place (do not create a new object).
Returns
-------
Series or DataFrame
When `drop` is False (the default), a DataFrame is returned.
The newly created columns will come first in the DataFrame,
followed by the original Series values.
When `drop` is True, a `Series` is returned.
In either case, if ``inplace=True``, no value is returned.
See Also
--------
DataFrame.reset_index: Analogous function for DataFrame.
Examples
--------
>>> s = pd.Series([1, 2, 3, 4], name='foo',
... index=pd.Index(['a', 'b', 'c', 'd'], name='idx'))
Generate a DataFrame with default index.
>>> s.reset_index()
idx foo
0 a 1
1 b 2
2 c 3
3 d 4
To specify the name of the new column use `name`.
>>> s.reset_index(name='values')
idx values
0 a 1
1 b 2
2 c 3
3 d 4
To generate a new Series with the default set `drop` to True.
>>> s.reset_index(drop=True)
0 1
1 2
2 3
3 4
Name: foo, dtype: int64
To update the Series in place, without generating a new one
set `inplace` to True. Note that it also requires ``drop=True``.
>>> s.reset_index(inplace=True, drop=True)
>>> s
0 1
1 2
2 3
3 4
Name: foo, dtype: int64
The `level` parameter is interesting for Series with a multi-level
index.
>>> arrays = [np.array(['bar', 'bar', 'baz', 'baz']),
... np.array(['one', 'two', 'one', 'two'])]
>>> s2 = pd.Series(
... range(4), name='foo',
... index=pd.MultiIndex.from_arrays(arrays,
... names=['a', 'b']))
To remove a specific level from the Index, use `level`.
>>> s2.reset_index(level='a')
a foo
b
one bar 0
two bar 1
one baz 2
two baz 3
If `level` is not set, all levels are removed from the Index.
>>> s2.reset_index()
a b foo
0 bar one 0
1 bar two 1
2 baz one 2
3 baz two 3
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if drop:
new_index = ibase.default_index(len(self))
if level is not None:
if not isinstance(level, (tuple, list)):
level = [level]
level = [self.index._get_level_number(lev) for lev in level]
if len(level) < self.index.nlevels:
new_index = self.index.droplevel(level)
if inplace:
self.index = new_index
# set name if it was passed, otherwise, keep the previous name
self.name = name or self.name
else:
return self._constructor(
self._values.copy(), index=new_index
).__finalize__(self, method="reset_index")
elif inplace:
raise TypeError(
"Cannot reset_index inplace on a Series to create a DataFrame"
)
else:
df = self.to_frame(name)
return df.reset_index(level=level, drop=drop)
# ----------------------------------------------------------------------
# Rendering Methods
def __repr__(self) -> str:
"""
Return a string representation for a particular Series.
"""
buf = StringIO("")
width, height = get_terminal_size()
max_rows = (
height
if get_option("display.max_rows") == 0
else get_option("display.max_rows")
)
min_rows = (
height
if get_option("display.max_rows") == 0
else get_option("display.min_rows")
)
show_dimensions = get_option("display.show_dimensions")
self.to_string(
buf=buf,
name=self.name,
dtype=self.dtype,
min_rows=min_rows,
max_rows=max_rows,
length=show_dimensions,
)
result = buf.getvalue()
return result
def to_string(
self,
buf=None,
na_rep="NaN",
float_format=None,
header=True,
index=True,
length=False,
dtype=False,
name=False,
max_rows=None,
min_rows=None,
):
"""
Render a string representation of the Series.
Parameters
----------
buf : StringIO-like, optional
Buffer to write to.
na_rep : str, optional
String representation of NaN to use, default 'NaN'.
float_format : one-parameter function, optional
Formatter function to apply to columns' elements if they are
floats, default None.
header : bool, default True
Add the Series header (index name).
index : bool, optional
Add index (row) labels, default True.
length : bool, default False
Add the Series length.
dtype : bool, default False
Add the Series dtype.
name : bool, default False
Add the Series name if not None.
max_rows : int, optional
Maximum number of rows to show before truncating. If None, show
all.
min_rows : int, optional
The number of rows to display in a truncated repr (when number
of rows is above `max_rows`).
Returns
-------
str or None
String representation of Series if ``buf=None``, otherwise None.
"""
formatter = fmt.SeriesFormatter(
self,
name=name,
length=length,
header=header,
index=index,
dtype=dtype,
na_rep=na_rep,
float_format=float_format,
min_rows=min_rows,
max_rows=max_rows,
)
result = formatter.to_string()
# catch contract violations
if not isinstance(result, str):
raise AssertionError(
"result must be of type str, type "
f"of result is {repr(type(result).__name__)}"
)
if buf is None:
return result
else:
try:
buf.write(result)
except AttributeError:
with open(buf, "w") as f:
f.write(result)
@Appender(
"""
Examples
--------
>>> s = pd.Series(["elk", "pig", "dog", "quetzal"], name="animal")
>>> print(s.to_markdown())
| | animal |
|---:|:---------|
| 0 | elk |
| 1 | pig |
| 2 | dog |
| 3 | quetzal |
"""
)
@Substitution(klass="Series")
@Appender(generic._shared_docs["to_markdown"])
def to_markdown(
self, buf: Optional[IO[str]] = None, mode: Optional[str] = None, **kwargs
) -> Optional[str]:
return self.to_frame().to_markdown(buf, mode, **kwargs)
# ----------------------------------------------------------------------
def items(self) -> Iterable[Tuple[Label, Any]]:
"""
Lazily iterate over (index, value) tuples.
This method returns an iterable tuple (index, value). This is
convenient if you want to create a lazy iterator.
Returns
-------
iterable
Iterable of tuples containing the (index, value) pairs from a
Series.
See Also
--------
DataFrame.items : Iterate over (column name, Series) pairs.
DataFrame.iterrows : Iterate over DataFrame rows as (index, Series) pairs.
Examples
--------
>>> s = pd.Series(['A', 'B', 'C'])
>>> for index, value in s.items():
... print(f"Index : {index}, Value : {value}")
Index : 0, Value : A
Index : 1, Value : B
Index : 2, Value : C
"""
return zip(iter(self.index), iter(self))
@Appender(items.__doc__)
def iteritems(self) -> Iterable[Tuple[Label, Any]]:
return self.items()
# ----------------------------------------------------------------------
# Misc public methods
def keys(self) -> Index:
"""
Return alias for index.
Returns
-------
Index
Index of the Series.
"""
return self.index
def to_dict(self, into=dict):
"""
Convert Series to {label -> value} dict or dict-like object.
Parameters
----------
into : class, default dict
The collections.abc.Mapping subclass to use as the return
object. Can be the actual class or an empty
instance of the mapping type you want. If you want a
collections.defaultdict, you must pass it initialized.
Returns
-------
collections.abc.Mapping
Key-value representation of Series.
Examples
--------
>>> s = pd.Series([1, 2, 3, 4])
>>> s.to_dict()
{0: 1, 1: 2, 2: 3, 3: 4}
>>> from collections import OrderedDict, defaultdict
>>> s.to_dict(OrderedDict)
OrderedDict([(0, 1), (1, 2), (2, 3), (3, 4)])
>>> dd = defaultdict(list)
>>> s.to_dict(dd)
defaultdict(<class 'list'>, {0: 1, 1: 2, 2: 3, 3: 4})
"""
# GH16122
into_c = com.standardize_mapping(into)
return into_c(self.items())
def to_frame(self, name=None) -> "DataFrame":
"""
Convert Series to DataFrame.
Parameters
----------
name : object, default None
The passed name should substitute for the series name (if it has
one).
Returns
-------
DataFrame
DataFrame representation of Series.
Examples
--------
>>> s = pd.Series(["a", "b", "c"],
... name="vals")
>>> s.to_frame()
vals
0 a
1 b
2 c
"""
if name is None:
df = self._constructor_expanddim(self)
else:
df = self._constructor_expanddim({name: self})
return df
def _set_name(self, name, inplace=False) -> "Series":
"""
Set the Series name.
Parameters
----------
name : str
inplace : bool
Whether to modify `self` directly or return a copy.
"""
inplace = validate_bool_kwarg(inplace, "inplace")
ser = self if inplace else self.copy()
ser.name = name
return ser
@Appender(
"""
Examples
--------
>>> ser = pd.Series([390., 350., 30., 20.],
... index=['Falcon', 'Falcon', 'Parrot', 'Parrot'], name="Max Speed")
>>> ser
Falcon 390.0
Falcon 350.0
Parrot 30.0
Parrot 20.0
Name: Max Speed, dtype: float64
>>> ser.groupby(["a", "b", "a", "b"]).mean()
a 210.0
b 185.0
Name: Max Speed, dtype: float64
>>> ser.groupby(level=0).mean()
Falcon 370.0
Parrot 25.0
Name: Max Speed, dtype: float64
>>> ser.groupby(ser > 100).mean()
Max Speed
False 25.0
True 370.0
Name: Max Speed, dtype: float64
**Grouping by Indexes**
We can groupby different levels of a hierarchical index
using the `level` parameter:
>>> arrays = [['Falcon', 'Falcon', 'Parrot', 'Parrot'],
... ['Captive', 'Wild', 'Captive', 'Wild']]
>>> index = pd.MultiIndex.from_arrays(arrays, names=('Animal', 'Type'))
>>> ser = pd.Series([390., 350., 30., 20.], index=index, name="Max Speed")
>>> ser
Animal Type
Falcon Captive 390.0
Wild 350.0
Parrot Captive 30.0
Wild 20.0
Name: Max Speed, dtype: float64
>>> ser.groupby(level=0).mean()
Animal
Falcon 370.0
Parrot 25.0
Name: Max Speed, dtype: float64
>>> ser.groupby(level="Type").mean()
Type
Captive 210.0
Wild 185.0
Name: Max Speed, dtype: float64
"""
)
@Appender(generic._shared_docs["groupby"] % _shared_doc_kwargs)
def groupby(
self,
by=None,
axis=0,
level=None,
as_index: bool = True,
sort: bool = True,
group_keys: bool = True,
squeeze: bool = False,
observed: bool = False,
) -> "SeriesGroupBy":
from pandas.core.groupby.generic import SeriesGroupBy
if level is None and by is None:
raise TypeError("You have to supply one of 'by' and 'level'")
axis = self._get_axis_number(axis)
return SeriesGroupBy(
obj=self,
keys=by,
axis=axis,
level=level,
as_index=as_index,
sort=sort,
group_keys=group_keys,
squeeze=squeeze,
observed=observed,
)
# ----------------------------------------------------------------------
# Statistics, overridden ndarray methods
# TODO: integrate bottleneck
def count(self, level=None):
"""
Return number of non-NA/null observations in the Series.
Parameters
----------
level : int or level name, default None
If the axis is a MultiIndex (hierarchical), count along a
particular level, collapsing into a smaller Series.
Returns
-------
int or Series (if level specified)
Number of non-null values in the Series.
See Also
--------
DataFrame.count : Count non-NA cells for each column or row.
Examples
--------
>>> s = pd.Series([0.0, 1.0, np.nan])
>>> s.count()
2
"""
if level is None:
return notna(self.array).sum()
if isinstance(level, str):
level = self.index._get_level_number(level)
lev = self.index.levels[level]
level_codes = np.array(self.index.codes[level], subok=False, copy=True)
mask = level_codes == -1
if mask.any():
level_codes[mask] = cnt = len(lev)
lev = lev.insert(cnt, lev._na_value)
obs = level_codes[notna(self._values)]
out = np.bincount(obs, minlength=len(lev) or None)
return self._constructor(out, index=lev, dtype="int64").__finalize__(
self, method="count"
)
def mode(self, dropna=True) -> "Series":
"""
Return the mode(s) of the dataset.
Always returns Series even if only one value is returned.
Parameters
----------
dropna : bool, default True
Don't consider counts of NaN/NaT.
.. versionadded:: 0.24.0
Returns
-------
Series
Modes of the Series in sorted order.
"""
# TODO: Add option for bins like value_counts()
return algorithms.mode(self, dropna=dropna)
def unique(self):
"""
Return unique values of Series object.
Uniques are returned in order of appearance. Hash table-based unique,
therefore does NOT sort.
Returns
-------
ndarray or ExtensionArray
The unique values returned as a NumPy array. See Notes.
See Also
--------
unique : Top-level unique method for any 1-d array-like object.
Index.unique : Return Index with unique values from an Index object.
Notes
-----
Returns the unique values as a NumPy array. In case of an
extension-array backed Series, a new
:class:`~api.extensions.ExtensionArray` of that type with just
the unique values is returned. This includes
* Categorical
* Period
* Datetime with Timezone
* Interval
* Sparse
* IntegerNA
See Examples section.
Examples
--------
>>> pd.Series([2, 1, 3, 3], name='A').unique()
array([2, 1, 3])
>>> pd.Series([pd.Timestamp('2016-01-01') for _ in range(3)]).unique()
array(['2016-01-01T00:00:00.000000000'], dtype='datetime64[ns]')
>>> pd.Series([pd.Timestamp('2016-01-01', tz='US/Eastern')
... for _ in range(3)]).unique()
<DatetimeArray>
['2016-01-01 00:00:00-05:00']
Length: 1, dtype: datetime64[ns, US/Eastern]
An unordered Categorical will return categories in the order of
appearance.
>>> pd.Series(pd.Categorical(list('baabc'))).unique()
[b, a, c]
Categories (3, object): [b, a, c]
An ordered Categorical preserves the category ordering.
>>> pd.Series(pd.Categorical(list('baabc'), categories=list('abc'),
... ordered=True)).unique()
[b, a, c]
Categories (3, object): [a < b < c]
"""
result = super().unique()
return result
def drop_duplicates(self, keep="first", inplace=False) -> Optional["Series"]:
"""
Return Series with duplicate values removed.
Parameters
----------
keep : {'first', 'last', ``False``}, default 'first'
Method to handle dropping duplicates:
- 'first' : Drop duplicates except for the first occurrence.
- 'last' : Drop duplicates except for the last occurrence.
- ``False`` : Drop all duplicates.
inplace : bool, default ``False``
If ``True``, performs operation inplace and returns None.
Returns
-------
Series
Series with duplicates dropped.
See Also
--------
Index.drop_duplicates : Equivalent method on Index.
DataFrame.drop_duplicates : Equivalent method on DataFrame.
Series.duplicated : Related method on Series, indicating duplicate
Series values.
Examples
--------
Generate a Series with duplicated entries.
>>> s = pd.Series(['lama', 'cow', 'lama', 'beetle', 'lama', 'hippo'],
... name='animal')
>>> s
0 lama
1 cow
2 lama
3 beetle
4 lama
5 hippo
Name: animal, dtype: object
With the 'keep' parameter, the selection behaviour of duplicated values
can be changed. The value 'first' keeps the first occurrence for each
set of duplicated entries. The default value of keep is 'first'.
>>> s.drop_duplicates()
0 lama
1 cow
3 beetle
5 hippo
Name: animal, dtype: object
The value 'last' for parameter 'keep' keeps the last occurrence for
each set of duplicated entries.
>>> s.drop_duplicates(keep='last')
1 cow
3 beetle
4 lama
5 hippo
Name: animal, dtype: object
The value ``False`` for parameter 'keep' discards all sets of
duplicated entries. Setting the value of 'inplace' to ``True`` performs
the operation inplace and returns ``None``.
>>> s.drop_duplicates(keep=False, inplace=True)
>>> s
1 cow
3 beetle
5 hippo
Name: animal, dtype: object
"""
inplace = validate_bool_kwarg(inplace, "inplace")
result = super().drop_duplicates(keep=keep)
if inplace:
self._update_inplace(result)
return None
else:
return result
def duplicated(self, keep="first") -> "Series":
"""
Indicate duplicate Series values.
Duplicated values are indicated as ``True`` values in the resulting
Series. Either all duplicates, all except the first or all except the
last occurrence of duplicates can be indicated.
Parameters
----------
keep : {'first', 'last', False}, default 'first'
Method to handle dropping duplicates:
- 'first' : Mark duplicates as ``True`` except for the first
occurrence.
- 'last' : Mark duplicates as ``True`` except for the last
occurrence.
- ``False`` : Mark all duplicates as ``True``.
Returns
-------
Series
Series indicating whether each value has occurred in the
preceding values.
See Also
--------
Index.duplicated : Equivalent method on pandas.Index.
DataFrame.duplicated : Equivalent method on pandas.DataFrame.
Series.drop_duplicates : Remove duplicate values from Series.
Examples
--------
By default, for each set of duplicated values, the first occurrence is
set on False and all others on True:
>>> animals = pd.Series(['lama', 'cow', 'lama', 'beetle', 'lama'])
>>> animals.duplicated()
0 False
1 False
2 True
3 False
4 True
dtype: bool
which is equivalent to
>>> animals.duplicated(keep='first')
0 False
1 False
2 True
3 False
4 True
dtype: bool
By using 'last', the last occurrence of each set of duplicated values
is set on False and all others on True:
>>> animals.duplicated(keep='last')
0 True
1 False
2 True
3 False
4 False
dtype: bool
By setting keep on ``False``, all duplicates are True:
>>> animals.duplicated(keep=False)
0 True
1 False
2 True
3 False
4 True
dtype: bool
"""
return super().duplicated(keep=keep)
def idxmin(self, axis=0, skipna=True, *args, **kwargs):
"""
Return the row label of the minimum value.
If multiple values equal the minimum, the first row label with that
value is returned.
Parameters
----------
axis : int, default 0
For compatibility with DataFrame.idxmin. Redundant for application
on Series.
skipna : bool, default True
Exclude NA/null values. If the entire Series is NA, the result
will be NA.
*args, **kwargs
Additional arguments and keywords have no effect but might be
accepted for compatibility with NumPy.
Returns
-------
Index
Label of the minimum value.
Raises
------
ValueError
If the Series is empty.
See Also
--------
numpy.argmin : Return indices of the minimum values
along the given axis.
DataFrame.idxmin : Return index of first occurrence of minimum
over requested axis.
Series.idxmax : Return index *label* of the first occurrence
of maximum of values.
Notes
-----
This method is the Series version of ``ndarray.argmin``. This method
returns the label of the minimum, while ``ndarray.argmin`` returns
the position. To get the position, use ``series.values.argmin()``.
Examples
--------
>>> s = pd.Series(data=[1, None, 4, 1],
... index=['A', 'B', 'C', 'D'])
>>> s
A 1.0
B NaN
C 4.0
D 1.0
dtype: float64
>>> s.idxmin()
'A'
If `skipna` is False and there is an NA value in the data,
the function returns ``nan``.
>>> s.idxmin(skipna=False)
nan
"""
skipna = nv.validate_argmin_with_skipna(skipna, args, kwargs)
i = nanops.nanargmin(self._values, skipna=skipna)
if i == -1:
return np.nan
return self.index[i]
def idxmax(self, axis=0, skipna=True, *args, **kwargs):
"""
Return the row label of the maximum value.
If multiple values equal the maximum, the first row label with that
value is returned.
Parameters
----------
axis : int, default 0
For compatibility with DataFrame.idxmax. Redundant for application
on Series.
skipna : bool, default True
Exclude NA/null values. If the entire Series is NA, the result
will be NA.
*args, **kwargs
Additional arguments and keywords have no effect but might be
accepted for compatibility with NumPy.
Returns
-------
Index
Label of the maximum value.
Raises
------
ValueError
If the Series is empty.
See Also
--------
numpy.argmax : Return indices of the maximum values
along the given axis.
DataFrame.idxmax : Return index of first occurrence of maximum
over requested axis.
Series.idxmin : Return index *label* of the first occurrence
of minimum of values.
Notes
-----
This method is the Series version of ``ndarray.argmax``. This method
returns the label of the maximum, while ``ndarray.argmax`` returns
the position. To get the position, use ``series.values.argmax()``.
Examples
--------
>>> s = pd.Series(data=[1, None, 4, 3, 4],
... index=['A', 'B', 'C', 'D', 'E'])
>>> s
A 1.0
B NaN
C 4.0
D 3.0
E 4.0
dtype: float64
>>> s.idxmax()
'C'
If `skipna` is False and there is an NA value in the data,
the function returns ``nan``.
>>> s.idxmax(skipna=False)
nan
"""
skipna = nv.validate_argmax_with_skipna(skipna, args, kwargs)
i = nanops.nanargmax(self._values, skipna=skipna)
if i == -1:
return np.nan
return self.index[i]
def round(self, decimals=0, *args, **kwargs) -> "Series":
"""
Round each value in a Series to the given number of decimals.
Parameters
----------
decimals : int, default 0
Number of decimal places to round to. If decimals is negative,
it specifies the number of positions to the left of the decimal point.
*args, **kwargs
Additional arguments and keywords have no effect but might be
accepted for compatibility with NumPy.
Returns
-------
Series
Rounded values of the Series.
See Also
--------
numpy.around : Round values of an np.array.
DataFrame.round : Round values of a DataFrame.
Examples
--------
>>> s = pd.Series([0.1, 1.3, 2.7])
>>> s.round()
0 0.0
1 1.0
2 3.0
dtype: float64
"""
nv.validate_round(args, kwargs)
result = self._values.round(decimals)
result = self._constructor(result, index=self.index).__finalize__(
self, method="round"
)
return result
def quantile(self, q=0.5, interpolation="linear"):
"""
Return value at the given quantile.
Parameters
----------
q : float or array-like, default 0.5 (50% quantile)
The quantile(s) to compute, which can lie in range: 0 <= q <= 1.
interpolation : {'linear', 'lower', 'higher', 'midpoint', 'nearest'}
This optional parameter specifies the interpolation method to use,
when the desired quantile lies between two data points `i` and `j`:
* linear: `i + (j - i) * fraction`, where `fraction` is the
fractional part of the index surrounded by `i` and `j`.
* lower: `i`.
* higher: `j`.
* nearest: `i` or `j` whichever is nearest.
* midpoint: (`i` + `j`) / 2.
Returns
-------
float or Series
If ``q`` is an array, a Series will be returned where the
index is ``q`` and the values are the quantiles, otherwise
a float will be returned.
See Also
--------
core.window.Rolling.quantile : Calculate the rolling quantile.
numpy.percentile : Returns the q-th percentile(s) of the array elements.
Examples
--------
>>> s = pd.Series([1, 2, 3, 4])
>>> s.quantile(.5)
2.5
>>> s.quantile([.25, .5, .75])
0.25 1.75
0.50 2.50
0.75 3.25
dtype: float64
"""
validate_percentile(q)
# We dispatch to DataFrame so that core.internals only has to worry
# about 2D cases.
df = self.to_frame()
result = df.quantile(q=q, interpolation=interpolation, numeric_only=False)
if result.ndim == 2:
result = result.iloc[:, 0]
if is_list_like(q):
result.name = self.name
return self._constructor(result, index=Float64Index(q), name=self.name)
else:
# scalar
return result.iloc[0]
def corr(self, other, method="pearson", min_periods=None) -> float:
"""
Compute correlation with `other` Series, excluding missing values.
Parameters
----------
other : Series
Series with which to compute the correlation.
method : {'pearson', 'kendall', 'spearman'} or callable
Method used to compute correlation:
- pearson : Standard correlation coefficient
- kendall : Kendall Tau correlation coefficient
- spearman : Spearman rank correlation
- callable: Callable with input two 1d ndarrays and returning a float.
.. versionadded:: 0.24.0
Note that the returned matrix from corr will have 1 along the
diagonals and will be symmetric regardless of the callable's
behavior.
min_periods : int, optional
Minimum number of observations needed to have a valid result.
Returns
-------
float
Correlation with other.
See Also
--------
DataFrame.corr : Compute pairwise correlation between columns.
DataFrame.corrwith : Compute pairwise correlation with another
DataFrame or Series.
Examples
--------
>>> def histogram_intersection(a, b):
... v = np.minimum(a, b).sum().round(decimals=1)
... return v
>>> s1 = pd.Series([.2, .0, .6, .2])
>>> s2 = pd.Series([.3, .6, .0, .1])
>>> s1.corr(s2, method=histogram_intersection)
0.3
"""
this, other = self.align(other, join="inner", copy=False)
if len(this) == 0:
return np.nan
if method in ["pearson", "spearman", "kendall"] or callable(method):
return nanops.nancorr(
this.values, other.values, method=method, min_periods=min_periods
)
raise ValueError(
"method must be either 'pearson', "
"'spearman', 'kendall', or a callable, "
f"'{method}' was supplied"
)
def cov(self, other, min_periods=None) -> float:
"""
Compute covariance with Series, excluding missing values.
Parameters
----------
other : Series
Series with which to compute the covariance.
min_periods : int, optional
Minimum number of observations needed to have a valid result.
Returns
-------
float
Covariance between Series and other normalized by N-1
(unbiased estimator).
See Also
--------
DataFrame.cov : Compute pairwise covariance of columns.
Examples
--------
>>> s1 = pd.Series([0.90010907, 0.13484424, 0.62036035])
>>> s2 = pd.Series([0.12528585, 0.26962463, 0.51111198])
>>> s1.cov(s2)
-0.01685762652715874
"""
this, other = self.align(other, join="inner", copy=False)
if len(this) == 0:
return np.nan
return nanops.nancov(this.values, other.values, min_periods=min_periods)
def diff(self, periods: int = 1) -> "Series":
"""
First discrete difference of element.
Calculates the difference of a Series element compared with another
element in the Series (default is element in previous row).
Parameters
----------
periods : int, default 1
Periods to shift for calculating difference, accepts negative
values.
Returns
-------
Series
First differences of the Series.
See Also
--------
Series.pct_change: Percent change over given number of periods.
Series.shift: Shift index by desired number of periods with an
optional time freq.
DataFrame.diff: First discrete difference of object.
Notes
-----
For boolean dtypes, this uses :meth:`operator.xor` rather than
:meth:`operator.sub`.
Examples
--------
Difference with previous row
>>> s = pd.Series([1, 1, 2, 3, 5, 8])
>>> s.diff()
0 NaN
1 0.0
2 1.0
3 1.0
4 2.0
5 3.0
dtype: float64
Difference with 3rd previous row
>>> s.diff(periods=3)
0 NaN
1 NaN
2 NaN
3 2.0
4 4.0
5 6.0
dtype: float64
Difference with following row
>>> s.diff(periods=-1)
0 0.0
1 -1.0
2 -1.0
3 -2.0
4 -3.0
5 NaN
dtype: float64
"""
result = algorithms.diff(self.array, periods)
return self._constructor(result, index=self.index).__finalize__(
self, method="diff"
)
def autocorr(self, lag=1) -> float:
"""
Compute the lag-N autocorrelation.
This method computes the Pearson correlation between
the Series and its shifted self.
Parameters
----------
lag : int, default 1
Number of lags to apply before performing autocorrelation.
Returns
-------
float
The Pearson correlation between self and self.shift(lag).
See Also
--------
Series.corr : Compute the correlation between two Series.
Series.shift : Shift index by desired number of periods.
DataFrame.corr : Compute pairwise correlation of columns.
DataFrame.corrwith : Compute pairwise correlation between rows or
columns of two DataFrame objects.
Notes
-----
If the Pearson correlation is not well defined return 'NaN'.
Examples
--------
>>> s = pd.Series([0.25, 0.5, 0.2, -0.05])
>>> s.autocorr() # doctest: +ELLIPSIS
0.10355...
>>> s.autocorr(lag=2) # doctest: +ELLIPSIS
-0.99999...
If the Pearson correlation is not well defined, then 'NaN' is returned.
>>> s = pd.Series([1, 0, 0, 0])
>>> s.autocorr()
nan
"""
return self.corr(self.shift(lag))
def dot(self, other):
"""
Compute the dot product between the Series and the columns of other.
This method computes the dot product between the Series and another
one, or the Series and each columns of a DataFrame, or the Series and
each columns of an array.
It can also be called using `self @ other` in Python >= 3.5.
Parameters
----------
other : Series, DataFrame or array-like
The other object to compute the dot product with its columns.
Returns
-------
scalar, Series or numpy.ndarray
Return the dot product of the Series and other if other is a
Series, the Series of the dot product of Series and each rows of
other if other is a DataFrame or a numpy.ndarray between the Series
and each columns of the numpy array.
See Also
--------
DataFrame.dot: Compute the matrix product with the DataFrame.
Series.mul: Multiplication of series and other, element-wise.
Notes
-----
The Series and other has to share the same index if other is a Series
or a DataFrame.
Examples
--------
>>> s = pd.Series([0, 1, 2, 3])
>>> other = pd.Series([-1, 2, -3, 4])
>>> s.dot(other)
8
>>> s @ other
8
>>> df = pd.DataFrame([[0, 1], [-2, 3], [4, -5], [6, 7]])
>>> s.dot(df)
0 24
1 14
dtype: int64
>>> arr = np.array([[0, 1], [-2, 3], [4, -5], [6, 7]])
>>> s.dot(arr)
array([24, 14])
"""
if isinstance(other, (Series, ABCDataFrame)):
common = self.index.union(other.index)
if len(common) > len(self.index) or len(common) > len(other.index):
raise ValueError("matrices are not aligned")
left = self.reindex(index=common, copy=False)
right = other.reindex(index=common, copy=False)
lvals = left.values
rvals = right.values
else:
lvals = self.values
rvals = np.asarray(other)
if lvals.shape[0] != rvals.shape[0]:
raise Exception(
f"Dot product shape mismatch, {lvals.shape} vs {rvals.shape}"
)
if isinstance(other, ABCDataFrame):
return self._constructor(
np.dot(lvals, rvals), index=other.columns
).__finalize__(self, method="dot")
elif isinstance(other, Series):
return np.dot(lvals, rvals)
elif isinstance(rvals, np.ndarray):
return np.dot(lvals, rvals)
else: # pragma: no cover
raise TypeError(f"unsupported type: {type(other)}")
def __matmul__(self, other):
"""
Matrix multiplication using binary `@` operator in Python>=3.5.
"""
return self.dot(other)
def __rmatmul__(self, other):
"""
Matrix multiplication using binary `@` operator in Python>=3.5.
"""
return self.dot(np.transpose(other))
@doc(base.IndexOpsMixin.searchsorted, klass="Series")
def searchsorted(self, value, side="left", sorter=None):
return algorithms.searchsorted(self._values, value, side=side, sorter=sorter)
# -------------------------------------------------------------------
# Combination
def append(self, to_append, ignore_index=False, verify_integrity=False):
"""
Concatenate two or more Series.
Parameters
----------
to_append : Series or list/tuple of Series
Series to append with self.
ignore_index : bool, default False
If True, do not use the index labels.
verify_integrity : bool, default False
If True, raise Exception on creating index with duplicates.
Returns
-------
Series
Concatenated Series.
See Also
--------
concat : General function to concatenate DataFrame or Series objects.
Notes
-----
Iteratively appending to a Series can be more computationally intensive
than a single concatenate. A better solution is to append values to a
list and then concatenate the list with the original Series all at
once.
Examples
--------
>>> s1 = pd.Series([1, 2, 3])
>>> s2 = pd.Series([4, 5, 6])
>>> s3 = pd.Series([4, 5, 6], index=[3, 4, 5])
>>> s1.append(s2)
0 1
1 2
2 3
0 4
1 5
2 6
dtype: int64
>>> s1.append(s3)
0 1
1 2
2 3
3 4
4 5
5 6
dtype: int64
With `ignore_index` set to True:
>>> s1.append(s2, ignore_index=True)
0 1
1 2
2 3
3 4
4 5
5 6
dtype: int64
With `verify_integrity` set to True:
>>> s1.append(s2, verify_integrity=True)
Traceback (most recent call last):
...
ValueError: Indexes have overlapping values: [0, 1, 2]
"""
from pandas.core.reshape.concat import concat
if isinstance(to_append, (list, tuple)):
to_concat = [self]
to_concat.extend(to_append)
else:
to_concat = [self, to_append]
if any(isinstance(x, (ABCDataFrame,)) for x in to_concat[1:]):
msg = (
f"to_append should be a Series or list/tuple of Series, "
f"got DataFrame"
)
raise TypeError(msg)
return concat(
to_concat, ignore_index=ignore_index, verify_integrity=verify_integrity
)
def _binop(self, other, func, level=None, fill_value=None):
"""
Perform generic binary operation with optional fill value.
Parameters
----------
other : Series
func : binary operator
fill_value : float or object
Value to substitute for NA/null values. If both Series are NA in a
location, the result will be NA regardless of the passed fill value.
level : int or level name, default None
Broadcast across a level, matching Index values on the
passed MultiIndex level.
Returns
-------
Series
"""
if not isinstance(other, Series):
raise AssertionError("Other operand must be Series")
this = self
if not self.index.equals(other.index):
this, other = self.align(other, level=level, join="outer", copy=False)
this_vals, other_vals = ops.fill_binop(this.values, other.values, fill_value)
with np.errstate(all="ignore"):
result = func(this_vals, other_vals)
name = ops.get_op_result_name(self, other)
ret = this._construct_result(result, name)
return ret
def _construct_result(
self, result: Union[ArrayLike, Tuple[ArrayLike, ArrayLike]], name: Label
) -> Union["Series", Tuple["Series", "Series"]]:
"""
Construct an appropriately-labelled Series from the result of an op.
Parameters
----------
result : ndarray or ExtensionArray
name : Label
Returns
-------
Series
In the case of __divmod__ or __rdivmod__, a 2-tuple of Series.
"""
if isinstance(result, tuple):
# produced by divmod or rdivmod
res1 = self._construct_result(result[0], name=name)
res2 = self._construct_result(result[1], name=name)
# GH#33427 assertions to keep mypy happy
assert isinstance(res1, Series)
assert isinstance(res2, Series)
return (res1, res2)
# We do not pass dtype to ensure that the Series constructor
# does inference in the case where `result` has object-dtype.
out = self._constructor(result, index=self.index)
out = out.__finalize__(self)
# Set the result's name after __finalize__ is called because __finalize__
# would set it back to self.name
out.name = name
return out
def combine(self, other, func, fill_value=None) -> "Series":
"""
Combine the Series with a Series or scalar according to `func`.
Combine the Series and `other` using `func` to perform elementwise
selection for combined Series.
`fill_value` is assumed when value is missing at some index
from one of the two objects being combined.
Parameters
----------
other : Series or scalar
The value(s) to be combined with the `Series`.
func : function
Function that takes two scalars as inputs and returns an element.
fill_value : scalar, optional
The value to assume when an index is missing from
one Series or the other. The default specifies to use the
appropriate NaN value for the underlying dtype of the Series.
Returns
-------
Series
The result of combining the Series with the other object.
See Also
--------
Series.combine_first : Combine Series values, choosing the calling
Series' values first.
Examples
--------
Consider 2 Datasets ``s1`` and ``s2`` containing
highest clocked speeds of different birds.
>>> s1 = pd.Series({'falcon': 330.0, 'eagle': 160.0})
>>> s1
falcon 330.0
eagle 160.0
dtype: float64
>>> s2 = pd.Series({'falcon': 345.0, 'eagle': 200.0, 'duck': 30.0})
>>> s2
falcon 345.0
eagle 200.0
duck 30.0
dtype: float64
Now, to combine the two datasets and view the highest speeds
of the birds across the two datasets
>>> s1.combine(s2, max)
duck NaN
eagle 200.0
falcon 345.0
dtype: float64
In the previous example, the resulting value for duck is missing,
because the maximum of a NaN and a float is a NaN.
So, in the example, we set ``fill_value=0``,
so the maximum value returned will be the value from some dataset.
>>> s1.combine(s2, max, fill_value=0)
duck 30.0
eagle 200.0
falcon 345.0
dtype: float64
"""
if fill_value is None:
fill_value = na_value_for_dtype(self.dtype, compat=False)
if isinstance(other, Series):
# If other is a Series, result is based on union of Series,
# so do this element by element
new_index = self.index.union(other.index)
new_name = ops.get_op_result_name(self, other)
new_values = []
for idx in new_index:
lv = self.get(idx, fill_value)
rv = other.get(idx, fill_value)
with np.errstate(all="ignore"):
new_values.append(func(lv, rv))
else:
# Assume that other is a scalar, so apply the function for
# each element in the Series
new_index = self.index
with np.errstate(all="ignore"):
new_values = [func(lv, other) for lv in self._values]
new_name = self.name
if is_categorical_dtype(self.dtype):
pass
elif is_extension_array_dtype(self.dtype):
# TODO: can we do this for only SparseDtype?
# The function can return something of any type, so check
# if the type is compatible with the calling EA.
new_values = maybe_cast_to_extension_array(type(self._values), new_values)
return self._constructor(new_values, index=new_index, name=new_name)
def combine_first(self, other) -> "Series":
"""
Combine Series values, choosing the calling Series's values first.
Parameters
----------
other : Series
The value(s) to be combined with the `Series`.
Returns
-------
Series
The result of combining the Series with the other object.
See Also
--------
Series.combine : Perform elementwise operation on two Series
using a given function.
Notes
-----
Result index will be the union of the two indexes.
Examples
--------
>>> s1 = pd.Series([1, np.nan])
>>> s2 = pd.Series([3, 4])
>>> s1.combine_first(s2)
0 1.0
1 4.0
dtype: float64
"""
new_index = self.index.union(other.index)
this = self.reindex(new_index, copy=False)
other = other.reindex(new_index, copy=False)
if this.dtype.kind == "M" and other.dtype.kind != "M":
other = to_datetime(other)
return this.where(notna(this), other)
def update(self, other) -> None:
"""
Modify Series in place using non-NA values from passed
Series. Aligns on index.
Parameters
----------
other : Series
Examples
--------
>>> s = pd.Series([1, 2, 3])
>>> s.update(pd.Series([4, 5, 6]))
>>> s
0 4
1 5
2 6
dtype: int64
>>> s = pd.Series(['a', 'b', 'c'])
>>> s.update(pd.Series(['d', 'e'], index=[0, 2]))
>>> s
0 d
1 b
2 e
dtype: object
>>> s = pd.Series([1, 2, 3])
>>> s.update(pd.Series([4, 5, 6, 7, 8]))
>>> s
0 4
1 5
2 6
dtype: int64
If ``other`` contains NaNs the corresponding values are not updated
in the original Series.
>>> s = pd.Series([1, 2, 3])
>>> s.update(pd.Series([4, np.nan, 6]))
>>> s
0 4
1 2
2 6
dtype: int64
"""
other = other.reindex_like(self)
mask = notna(other)
self._mgr = self._mgr.putmask(mask=mask, new=other)
self._maybe_update_cacher()
# ----------------------------------------------------------------------
# Reindexing, sorting
def sort_values(
self,
axis=0,
ascending=True,
inplace: bool = False,
kind: str = "quicksort",
na_position: str = "last",
ignore_index: bool = False,
):
"""
Sort by the values.
Sort a Series in ascending or descending order by some
criterion.
Parameters
----------
axis : {0 or 'index'}, default 0
Axis to direct sorting. The value 'index' is accepted for
compatibility with DataFrame.sort_values.
ascending : bool, default True
If True, sort values in ascending order, otherwise descending.
inplace : bool, default False
If True, perform operation in-place.
kind : {'quicksort', 'mergesort' or 'heapsort'}, default 'quicksort'
Choice of sorting algorithm. See also :func:`numpy.sort` for more
information. 'mergesort' is the only stable algorithm.
na_position : {'first' or 'last'}, default 'last'
Argument 'first' puts NaNs at the beginning, 'last' puts NaNs at
the end.
ignore_index : bool, default False
If True, the resulting axis will be labeled 0, 1, …, n - 1.
.. versionadded:: 1.0.0
Returns
-------
Series
Series ordered by values.
See Also
--------
Series.sort_index : Sort by the Series indices.
DataFrame.sort_values : Sort DataFrame by the values along either axis.
DataFrame.sort_index : Sort DataFrame by indices.
Examples
--------
>>> s = pd.Series([np.nan, 1, 3, 10, 5])
>>> s
0 NaN
1 1.0
2 3.0
3 10.0
4 5.0
dtype: float64
Sort values ascending order (default behaviour)
>>> s.sort_values(ascending=True)
1 1.0
2 3.0
4 5.0
3 10.0
0 NaN
dtype: float64
Sort values descending order
>>> s.sort_values(ascending=False)
3 10.0
4 5.0
2 3.0
1 1.0
0 NaN
dtype: float64
Sort values inplace
>>> s.sort_values(ascending=False, inplace=True)
>>> s
3 10.0
4 5.0
2 3.0
1 1.0
0 NaN
dtype: float64
Sort values putting NAs first
>>> s.sort_values(na_position='first')
0 NaN
1 1.0
2 3.0
4 5.0
3 10.0
dtype: float64
Sort a series of strings
>>> s = pd.Series(['z', 'b', 'd', 'a', 'c'])
>>> s
0 z
1 b
2 d
3 a
4 c
dtype: object
>>> s.sort_values()
3 a
1 b
4 c
2 d
0 z
dtype: object
"""
inplace = validate_bool_kwarg(inplace, "inplace")
# Validate the axis parameter
self._get_axis_number(axis)
# GH 5856/5853
if inplace and self._is_cached:
raise ValueError(
"This Series is a view of some other array, to "
"sort in-place you must create a copy"
)
def _try_kind_sort(arr):
# easier to ask forgiveness than permission
try:
# if kind==mergesort, it can fail for object dtype
return arr.argsort(kind=kind)
except TypeError:
# stable sort not available for object dtype
# uses the argsort default quicksort
return arr.argsort(kind="quicksort")
arr = self._values
sorted_index = np.empty(len(self), dtype=np.int32)
bad = isna(arr)
good = ~bad
idx = ibase.default_index(len(self))
argsorted = _try_kind_sort(arr[good])
if is_list_like(ascending):
if len(ascending) != 1:
raise ValueError(
f"Length of ascending ({len(ascending)}) must be 1 for Series"
)
ascending = ascending[0]
if not is_bool(ascending):
raise ValueError("ascending must be boolean")
if not ascending:
argsorted = argsorted[::-1]
if na_position == "last":
n = good.sum()
sorted_index[:n] = idx[good][argsorted]
sorted_index[n:] = idx[bad]
elif na_position == "first":
n = bad.sum()
sorted_index[n:] = idx[good][argsorted]
sorted_index[:n] = idx[bad]
else:
raise ValueError(f"invalid na_position: {na_position}")
result = self._constructor(arr[sorted_index], index=self.index[sorted_index])
if ignore_index:
result.index = ibase.default_index(len(sorted_index))
if inplace:
self._update_inplace(result)
else:
return result.__finalize__(self, method="sort_values")
def sort_index(
self,
axis=0,
level=None,
ascending: bool = True,
inplace: bool = False,
kind: str = "quicksort",
na_position: str = "last",
sort_remaining: bool = True,
ignore_index: bool = False,
):
"""
Sort Series by index labels.
Returns a new Series sorted by label if `inplace` argument is
``False``, otherwise updates the original series and returns None.
Parameters
----------
axis : int, default 0
Axis to direct sorting. This can only be 0 for Series.
level : int, optional
If not None, sort on values in specified index level(s).
ascending : bool or list of bools, default True
Sort ascending vs. descending. When the index is a MultiIndex the
sort direction can be controlled for each level individually.
inplace : bool, default False
If True, perform operation in-place.
kind : {'quicksort', 'mergesort', 'heapsort'}, default 'quicksort'
Choice of sorting algorithm. See also :func:`numpy.sort` for more
information. 'mergesort' is the only stable algorithm. For
DataFrames, this option is only applied when sorting on a single
column or label.
na_position : {'first', 'last'}, default 'last'
If 'first' puts NaNs at the beginning, 'last' puts NaNs at the end.
Not implemented for MultiIndex.
sort_remaining : bool, default True
If True and sorting by level and index is multilevel, sort by other
levels too (in order) after sorting by specified level.
ignore_index : bool, default False
If True, the resulting axis will be labeled 0, 1, …, n - 1.
.. versionadded:: 1.0.0
Returns
-------
Series
The original Series sorted by the labels.
See Also
--------
DataFrame.sort_index: Sort DataFrame by the index.
DataFrame.sort_values: Sort DataFrame by the value.
Series.sort_values : Sort Series by the value.
Examples
--------
>>> s = pd.Series(['a', 'b', 'c', 'd'], index=[3, 2, 1, 4])
>>> s.sort_index()
1 c
2 b
3 a
4 d
dtype: object
Sort Descending
>>> s.sort_index(ascending=False)
4 d
3 a
2 b
1 c
dtype: object
Sort Inplace
>>> s.sort_index(inplace=True)
>>> s
1 c
2 b
3 a
4 d
dtype: object
By default NaNs are put at the end, but use `na_position` to place
them at the beginning
>>> s = pd.Series(['a', 'b', 'c', 'd'], index=[3, 2, 1, np.nan])
>>> s.sort_index(na_position='first')
NaN d
1.0 c
2.0 b
3.0 a
dtype: object
Specify index level to sort
>>> arrays = [np.array(['qux', 'qux', 'foo', 'foo',
... 'baz', 'baz', 'bar', 'bar']),
... np.array(['two', 'one', 'two', 'one',
... 'two', 'one', 'two', 'one'])]
>>> s = pd.Series([1, 2, 3, 4, 5, 6, 7, 8], index=arrays)
>>> s.sort_index(level=1)
bar one 8
baz one 6
foo one 4
qux one 2
bar two 7
baz two 5
foo two 3
qux two 1
dtype: int64
Does not sort by remaining levels when sorting by levels
>>> s.sort_index(level=1, sort_remaining=False)
qux one 2
foo one 4
baz one 6
bar one 8
qux two 1
foo two 3
baz two 5
bar two 7
dtype: int64
"""
# TODO: this can be combined with DataFrame.sort_index impl as
# almost identical
inplace = validate_bool_kwarg(inplace, "inplace")
# Validate the axis parameter
self._get_axis_number(axis)
index = self.index
if level is not None:
new_index, indexer = index.sortlevel(
level, ascending=ascending, sort_remaining=sort_remaining
)
elif isinstance(index, MultiIndex):
from pandas.core.sorting import lexsort_indexer
labels = index._sort_levels_monotonic()
indexer = lexsort_indexer(
labels._get_codes_for_sorting(),
orders=ascending,
na_position=na_position,
)
else:
from pandas.core.sorting import nargsort
# Check monotonic-ness before sort an index
# GH11080
if (ascending and index.is_monotonic_increasing) or (
not ascending and index.is_monotonic_decreasing
):
if inplace:
return
else:
return self.copy()
indexer = nargsort(
index, kind=kind, ascending=ascending, na_position=na_position
)
indexer = ensure_platform_int(indexer)
new_index = index.take(indexer)
new_index = new_index._sort_levels_monotonic()
new_values = self._values.take(indexer)
result = self._constructor(new_values, index=new_index)
if ignore_index:
result.index = ibase.default_index(len(result))
if inplace:
self._update_inplace(result)
else:
return result.__finalize__(self, method="sort_index")
def argsort(self, axis=0, kind="quicksort", order=None) -> "Series":
"""
Override ndarray.argsort. Argsorts the value, omitting NA/null values,
and places the result in the same locations as the non-NA values.
Parameters
----------
axis : {0 or "index"}
Has no effect but is accepted for compatibility with numpy.
kind : {'mergesort', 'quicksort', 'heapsort'}, default 'quicksort'
Choice of sorting algorithm. See np.sort for more
information. 'mergesort' is the only stable algorithm.
order : None
Has no effect but is accepted for compatibility with numpy.
Returns
-------
Series
Positions of values within the sort order with -1 indicating
nan values.
See Also
--------
numpy.ndarray.argsort : Returns the indices that would sort this array.
"""
values = self._values
mask = isna(values)
if mask.any():
result = Series(-1, index=self.index, name=self.name, dtype="int64")
notmask = ~mask
result[notmask] = np.argsort(values[notmask], kind=kind)
return self._constructor(result, index=self.index).__finalize__(
self, method="argsort"
)
else:
return self._constructor(
np.argsort(values, kind=kind), index=self.index, dtype="int64"
).__finalize__(self, method="argsort")
def nlargest(self, n=5, keep="first") -> "Series":
"""
Return the largest `n` elements.
Parameters
----------
n : int, default 5
Return this many descending sorted values.
keep : {'first', 'last', 'all'}, default 'first'
When there are duplicate values that cannot all fit in a
Series of `n` elements:
- ``first`` : return the first `n` occurrences in order
of appearance.
- ``last`` : return the last `n` occurrences in reverse
order of appearance.
- ``all`` : keep all occurrences. This can result in a Series of
size larger than `n`.
Returns
-------
Series
The `n` largest values in the Series, sorted in decreasing order.
See Also
--------
Series.nsmallest: Get the `n` smallest elements.
Series.sort_values: Sort Series by values.
Series.head: Return the first `n` rows.
Notes
-----
Faster than ``.sort_values(ascending=False).head(n)`` for small `n`
relative to the size of the ``Series`` object.
Examples
--------
>>> countries_population = {"Italy": 59000000, "France": 65000000,
... "Malta": 434000, "Maldives": 434000,
... "Brunei": 434000, "Iceland": 337000,
... "Nauru": 11300, "Tuvalu": 11300,
... "Anguilla": 11300, "Monserat": 5200}
>>> s = pd.Series(countries_population)
>>> s
Italy 59000000
France 65000000
Malta 434000
Maldives 434000
Brunei 434000
Iceland 337000
Nauru 11300
Tuvalu 11300
Anguilla 11300
Monserat 5200
dtype: int64
The `n` largest elements where ``n=5`` by default.
>>> s.nlargest()
France 65000000
Italy 59000000
Malta 434000
Maldives 434000
Brunei 434000
dtype: int64
The `n` largest elements where ``n=3``. Default `keep` value is 'first'
so Malta will be kept.
>>> s.nlargest(3)
France 65000000
Italy 59000000
Malta 434000
dtype: int64
The `n` largest elements where ``n=3`` and keeping the last duplicates.
Brunei will be kept since it is the last with value 434000 based on
the index order.
>>> s.nlargest(3, keep='last')
France 65000000
Italy 59000000
Brunei 434000
dtype: int64
The `n` largest elements where ``n=3`` with all duplicates kept. Note
that the returned Series has five elements due to the three duplicates.
>>> s.nlargest(3, keep='all')
France 65000000
Italy 59000000
Malta 434000
Maldives 434000
Brunei 434000
dtype: int64
"""
return algorithms.SelectNSeries(self, n=n, keep=keep).nlargest()
def nsmallest(self, n=5, keep="first") -> "Series":
"""
Return the smallest `n` elements.
Parameters
----------
n : int, default 5
Return this many ascending sorted values.
keep : {'first', 'last', 'all'}, default 'first'
When there are duplicate values that cannot all fit in a
Series of `n` elements:
- ``first`` : return the first `n` occurrences in order
of appearance.
- ``last`` : return the last `n` occurrences in reverse
order of appearance.
- ``all`` : keep all occurrences. This can result in a Series of
size larger than `n`.
Returns
-------
Series
The `n` smallest values in the Series, sorted in increasing order.
See Also
--------
Series.nlargest: Get the `n` largest elements.
Series.sort_values: Sort Series by values.
Series.head: Return the first `n` rows.
Notes
-----
Faster than ``.sort_values().head(n)`` for small `n` relative to
the size of the ``Series`` object.
Examples
--------
>>> countries_population = {"Italy": 59000000, "France": 65000000,
... "Brunei": 434000, "Malta": 434000,
... "Maldives": 434000, "Iceland": 337000,
... "Nauru": 11300, "Tuvalu": 11300,
... "Anguilla": 11300, "Monserat": 5200}
>>> s = pd.Series(countries_population)
>>> s
Italy 59000000
France 65000000
Brunei 434000
Malta 434000
Maldives 434000
Iceland 337000
Nauru 11300
Tuvalu 11300
Anguilla 11300
Monserat 5200
dtype: int64
The `n` smallest elements where ``n=5`` by default.
>>> s.nsmallest()
Monserat 5200
Nauru 11300
Tuvalu 11300
Anguilla 11300
Iceland 337000
dtype: int64
The `n` smallest elements where ``n=3``. Default `keep` value is
'first' so Nauru and Tuvalu will be kept.
>>> s.nsmallest(3)
Monserat 5200
Nauru 11300
Tuvalu 11300
dtype: int64
The `n` smallest elements where ``n=3`` and keeping the last
duplicates. Anguilla and Tuvalu will be kept since they are the last
with value 11300 based on the index order.
>>> s.nsmallest(3, keep='last')
Monserat 5200
Anguilla 11300
Tuvalu 11300
dtype: int64
The `n` smallest elements where ``n=3`` with all duplicates kept. Note
that the returned Series has four elements due to the three duplicates.
>>> s.nsmallest(3, keep='all')
Monserat 5200
Nauru 11300
Tuvalu 11300
Anguilla 11300
dtype: int64
"""
return algorithms.SelectNSeries(self, n=n, keep=keep).nsmallest()
def swaplevel(self, i=-2, j=-1, copy=True) -> "Series":
"""
Swap levels i and j in a :class:`MultiIndex`.
Default is to swap the two innermost levels of the index.
Parameters
----------
i, j : int, str
Level of the indices to be swapped. Can pass level name as string.
copy : bool, default True
Whether to copy underlying data.
Returns
-------
Series
Series with levels swapped in MultiIndex.
"""
assert isinstance(self.index, ABCMultiIndex)
new_index = self.index.swaplevel(i, j)
return self._constructor(self._values, index=new_index, copy=copy).__finalize__(
self, method="swaplevel"
)
def reorder_levels(self, order) -> "Series":
"""
Rearrange index levels using input order.
May not drop or duplicate levels.
Parameters
----------
order : list of int representing new level order
Reference level by number or key.
Returns
-------
type of caller (new object)
"""
if not isinstance(self.index, MultiIndex): # pragma: no cover
raise Exception("Can only reorder levels on a hierarchical axis.")
result = self.copy()
assert isinstance(result.index, ABCMultiIndex)
result.index = result.index.reorder_levels(order)
return result
def explode(self) -> "Series":
"""
Transform each element of a list-like to a row, replicating the
index values.
.. versionadded:: 0.25.0
Returns
-------
Series
Exploded lists to rows; index will be duplicated for these rows.
See Also
--------
Series.str.split : Split string values on specified separator.
Series.unstack : Unstack, a.k.a. pivot, Series with MultiIndex
to produce DataFrame.
DataFrame.melt : Unpivot a DataFrame from wide format to long format.
DataFrame.explode : Explode a DataFrame from list-like
columns to long format.
Notes
-----
This routine will explode list-likes including lists, tuples,
Series, and np.ndarray. The result dtype of the subset rows will
be object. Scalars will be returned unchanged. Empty list-likes will
result in a np.nan for that row.
Examples
--------
>>> s = pd.Series([[1, 2, 3], 'foo', [], [3, 4]])
>>> s
0 [1, 2, 3]
1 foo
2 []
3 [3, 4]
dtype: object
>>> s.explode()
0 1
0 2
0 3
1 foo
2 NaN
3 3
3 4
dtype: object
"""
if not len(self) or not is_object_dtype(self):
return self.copy()
values, counts = reshape.explode(np.asarray(self.array))
result = Series(values, index=self.index.repeat(counts), name=self.name)
return result
def unstack(self, level=-1, fill_value=None):
"""
Unstack, also known as pivot, Series with MultiIndex to produce DataFrame.
The level involved will automatically get sorted.
Parameters
----------
level : int, str, or list of these, default last level
Level(s) to unstack, can pass level name.
fill_value : scalar value, default None
Value to use when replacing NaN values.
Returns
-------
DataFrame
Unstacked Series.
Examples
--------
>>> s = pd.Series([1, 2, 3, 4],
... index=pd.MultiIndex.from_product([['one', 'two'],
... ['a', 'b']]))
>>> s
one a 1
b 2
two a 3
b 4
dtype: int64
>>> s.unstack(level=-1)
a b
one 1 2
two 3 4
>>> s.unstack(level=0)
one two
a 1 3
b 2 4
"""
from pandas.core.reshape.reshape import unstack
return unstack(self, level, fill_value)
# ----------------------------------------------------------------------
# function application
def map(self, arg, na_action=None) -> "Series":
"""
Map values of Series according to input correspondence.
Used for substituting each value in a Series with another value,
that may be derived from a function, a ``dict`` or
a :class:`Series`.
Parameters
----------
arg : function, collections.abc.Mapping subclass or Series
Mapping correspondence.
na_action : {None, 'ignore'}, default None
If 'ignore', propagate NaN values, without passing them to the
mapping correspondence.
Returns
-------
Series
Same index as caller.
See Also
--------
Series.apply : For applying more complex functions on a Series.
DataFrame.apply : Apply a function row-/column-wise.
DataFrame.applymap : Apply a function elementwise on a whole DataFrame.
Notes
-----
When ``arg`` is a dictionary, values in Series that are not in the
dictionary (as keys) are converted to ``NaN``. However, if the
dictionary is a ``dict`` subclass that defines ``__missing__`` (i.e.
provides a method for default values), then this default is used
rather than ``NaN``.
Examples
--------
>>> s = pd.Series(['cat', 'dog', np.nan, 'rabbit'])
>>> s
0 cat
1 dog
2 NaN
3 rabbit
dtype: object
``map`` accepts a ``dict`` or a ``Series``. Values that are not found
in the ``dict`` are converted to ``NaN``, unless the dict has a default
value (e.g. ``defaultdict``):
>>> s.map({'cat': 'kitten', 'dog': 'puppy'})
0 kitten
1 puppy
2 NaN
3 NaN
dtype: object
It also accepts a function:
>>> s.map('I am a {}'.format)
0 I am a cat
1 I am a dog
2 I am a nan
3 I am a rabbit
dtype: object
To avoid applying the function to missing values (and keep them as
``NaN``) ``na_action='ignore'`` can be used:
>>> s.map('I am a {}'.format, na_action='ignore')
0 I am a cat
1 I am a dog
2 NaN
3 I am a rabbit
dtype: object
"""
new_values = super()._map_values(arg, na_action=na_action)
return self._constructor(new_values, index=self.index).__finalize__(
self, method="map"
)
def _gotitem(self, key, ndim, subset=None) -> "Series":
"""
Sub-classes to define. Return a sliced object.
Parameters
----------
key : string / list of selections
ndim : 1,2
Requested ndim of result.
subset : object, default None
Subset to act on.
"""
return self
_agg_see_also_doc = dedent(
"""
See Also
--------
Series.apply : Invoke function on a Series.
Series.transform : Transform function producing a Series with like indexes.
"""
)
_agg_examples_doc = dedent(
"""
Examples
--------
>>> s = pd.Series([1, 2, 3, 4])
>>> s
0 1
1 2
2 3
3 4
dtype: int64
>>> s.agg('min')
1
>>> s.agg(['min', 'max'])
min 1
max 4
dtype: int64
"""
)
@Substitution(
see_also=_agg_see_also_doc,
examples=_agg_examples_doc,
versionadded="\n.. versionadded:: 0.20.0\n",
**_shared_doc_kwargs,
)
@Appender(generic._shared_docs["aggregate"])
def aggregate(self, func, axis=0, *args, **kwargs):
# Validate the axis parameter
self._get_axis_number(axis)
result, how = self._aggregate(func, *args, **kwargs)
if result is None:
# we can be called from an inner function which
# passes this meta-data
kwargs.pop("_axis", None)
kwargs.pop("_level", None)
# try a regular apply, this evaluates lambdas
# row-by-row; however if the lambda is expected a Series
# expression, e.g.: lambda x: x-x.quantile(0.25)
# this will fail, so we can try a vectorized evaluation
# we cannot FIRST try the vectorized evaluation, because
# then .agg and .apply would have different semantics if the
# operation is actually defined on the Series, e.g. str
try:
result = self.apply(func, *args, **kwargs)
except (ValueError, AttributeError, TypeError):
result = func(self, *args, **kwargs)
return result
agg = aggregate
@Appender(generic._shared_docs["transform"] % _shared_doc_kwargs)
def transform(self, func, axis=0, *args, **kwargs):
# Validate the axis parameter
self._get_axis_number(axis)
return super().transform(func, *args, **kwargs)
def apply(self, func, convert_dtype=True, args=(), **kwds):
"""
Invoke function on values of Series.
Can be ufunc (a NumPy function that applies to the entire Series)
or a Python function that only works on single values.
Parameters
----------
func : function
Python function or NumPy ufunc to apply.
convert_dtype : bool, default True
Try to find better dtype for elementwise function results. If
False, leave as dtype=object.
args : tuple
Positional arguments passed to func after the series value.
**kwds
Additional keyword arguments passed to func.
Returns
-------
Series or DataFrame
If func returns a Series object the result will be a DataFrame.
See Also
--------
Series.map: For element-wise operations.
Series.agg: Only perform aggregating type operations.
Series.transform: Only perform transforming type operations.
Examples
--------
Create a series with typical summer temperatures for each city.
>>> s = pd.Series([20, 21, 12],
... index=['London', 'New York', 'Helsinki'])
>>> s
London 20
New York 21
Helsinki 12
dtype: int64
Square the values by defining a function and passing it as an
argument to ``apply()``.
>>> def square(x):
... return x ** 2
>>> s.apply(square)
London 400
New York 441
Helsinki 144
dtype: int64
Square the values by passing an anonymous function as an
argument to ``apply()``.
>>> s.apply(lambda x: x ** 2)
London 400
New York 441
Helsinki 144
dtype: int64
Define a custom function that needs additional positional
arguments and pass these additional arguments using the
``args`` keyword.
>>> def subtract_custom_value(x, custom_value):
... return x - custom_value
>>> s.apply(subtract_custom_value, args=(5,))
London 15
New York 16
Helsinki 7
dtype: int64
Define a custom function that takes keyword arguments
and pass these arguments to ``apply``.
>>> def add_custom_values(x, **kwargs):
... for month in kwargs:
... x += kwargs[month]
... return x
>>> s.apply(add_custom_values, june=30, july=20, august=25)
London 95
New York 96
Helsinki 87
dtype: int64
Use a function from the Numpy library.
>>> s.apply(np.log)
London 2.995732
New York 3.044522
Helsinki 2.484907
dtype: float64
"""
if len(self) == 0:
return self._constructor(dtype=self.dtype, index=self.index).__finalize__(
self, method="apply"
)
# dispatch to agg
if isinstance(func, (list, dict)):
return self.aggregate(func, *args, **kwds)
# if we are a string, try to dispatch
if isinstance(func, str):
return self._try_aggregate_string_function(func, *args, **kwds)
# handle ufuncs and lambdas
if kwds or args and not isinstance(func, np.ufunc):
def f(x):
return func(x, *args, **kwds)
else:
f = func
with np.errstate(all="ignore"):
if isinstance(f, np.ufunc):
return f(self)
# row-wise access
if is_extension_array_dtype(self.dtype) and hasattr(self._values, "map"):
# GH#23179 some EAs do not have `map`
mapped = self._values.map(f)
else:
values = self.astype(object)._values
mapped = lib.map_infer(values, f, convert=convert_dtype)
if len(mapped) and isinstance(mapped[0], Series):
# GH 25959 use pd.array instead of tolist
# so extension arrays can be used
return self._constructor_expanddim(pd.array(mapped), index=self.index)
else:
return self._constructor(mapped, index=self.index).__finalize__(
self, method="apply"
)
def _reduce(
self, op, name, axis=0, skipna=True, numeric_only=None, filter_type=None, **kwds
):
"""
Perform a reduction operation.
If we have an ndarray as a value, then simply perform the operation,
otherwise delegate to the object.
"""
delegate = self._values
if axis is not None:
self._get_axis_number(axis)
if isinstance(delegate, ExtensionArray):
# dispatch to ExtensionArray interface
return delegate._reduce(name, skipna=skipna, **kwds)
else:
# dispatch to numpy arrays
if numeric_only:
raise NotImplementedError(
f"Series.{name} does not implement numeric_only."
)
with np.errstate(all="ignore"):
return op(delegate, skipna=skipna, **kwds)
def _reindex_indexer(self, new_index, indexer, copy):
if indexer is None:
if copy:
return self.copy()
return self
new_values = algorithms.take_1d(
self._values, indexer, allow_fill=True, fill_value=None
)
return self._constructor(new_values, index=new_index)
def _needs_reindex_multi(self, axes, method, level):
"""
Check if we do need a multi reindex; this is for compat with
higher dims.
"""
return False
@doc(NDFrame.align, **_shared_doc_kwargs)
def align(
self,
other,
join="outer",
axis=None,
level=None,
copy=True,
fill_value=None,
method=None,
limit=None,
fill_axis=0,
broadcast_axis=None,
):
return super().align(
other,
join=join,
axis=axis,
level=level,
copy=copy,
fill_value=fill_value,
method=method,
limit=limit,
fill_axis=fill_axis,
broadcast_axis=broadcast_axis,
)
def rename(
self,
index=None,
*,
axis=None,
copy=True,
inplace=False,
level=None,
errors="ignore",
):
"""
Alter Series index labels or name.
Function / dict values must be unique (1-to-1). Labels not contained in
a dict / Series will be left as-is. Extra labels listed don't throw an
error.
Alternatively, change ``Series.name`` with a scalar value.
See the :ref:`user guide <basics.rename>` for more.
Parameters
----------
axis : {0 or "index"}
Unused. Accepted for compatibility with DataFrame method only.
index : scalar, hashable sequence, dict-like or function, optional
Functions or dict-like are transformations to apply to
the index.
Scalar or hashable sequence-like will alter the ``Series.name``
attribute.
**kwargs
Additional keyword arguments passed to the function. Only the
"inplace" keyword is used.
Returns
-------
Series
Series with index labels or name altered.
See Also
--------
DataFrame.rename : Corresponding DataFrame method.
Series.rename_axis : Set the name of the axis.
Examples
--------
>>> s = pd.Series([1, 2, 3])
>>> s
0 1
1 2
2 3
dtype: int64
>>> s.rename("my_name") # scalar, changes Series.name
0 1
1 2
2 3
Name: my_name, dtype: int64
>>> s.rename(lambda x: x ** 2) # function, changes labels
0 1
1 2
4 3
dtype: int64
>>> s.rename({1: 3, 2: 5}) # mapping, changes labels
0 1
3 2
5 3
dtype: int64
"""
if callable(index) or is_dict_like(index):
return super().rename(
index, copy=copy, inplace=inplace, level=level, errors=errors
)
else:
return self._set_name(index, inplace=inplace)
@Appender(
"""
Examples
--------
>>> s = pd.Series([1, 2, 3])
>>> s
0 1
1 2
2 3
dtype: int64
>>> s.set_axis(['a', 'b', 'c'], axis=0)
a 1
b 2
c 3
dtype: int64
"""
)
@Substitution(
**_shared_doc_kwargs,
extended_summary_sub="",
axis_description_sub="",
see_also_sub="",
)
@Appender(generic.NDFrame.set_axis.__doc__)
def set_axis(self, labels, axis: Axis = 0, inplace: bool = False):
return super().set_axis(labels, axis=axis, inplace=inplace)
@Substitution(**_shared_doc_kwargs)
@Appender(generic.NDFrame.reindex.__doc__)
def reindex(self, index=None, **kwargs):
return super().reindex(index=index, **kwargs)
def drop(
self,
labels=None,
axis=0,
index=None,
columns=None,
level=None,
inplace=False,
errors="raise",
) -> "Series":
"""
Return Series with specified index labels removed.
Remove elements of a Series based on specifying the index labels.
When using a multi-index, labels on different levels can be removed
by specifying the level.
Parameters
----------
labels : single label or list-like
Index labels to drop.
axis : 0, default 0
Redundant for application on Series.
index : single label or list-like
Redundant for application on Series, but 'index' can be used instead
of 'labels'.
columns : single label or list-like
No change is made to the Series; use 'index' or 'labels' instead.
level : int or level name, optional
For MultiIndex, level for which the labels will be removed.
inplace : bool, default False
If True, do operation inplace and return None.
errors : {'ignore', 'raise'}, default 'raise'
If 'ignore', suppress error and only existing labels are dropped.
Returns
-------
Series
Series with specified index labels removed.
Raises
------
KeyError
If none of the labels are found in the index.
See Also
--------
Series.reindex : Return only specified index labels of Series.
Series.dropna : Return series without null values.
Series.drop_duplicates : Return Series with duplicate values removed.
DataFrame.drop : Drop specified labels from rows or columns.
Examples
--------
>>> s = pd.Series(data=np.arange(3), index=['A', 'B', 'C'])
>>> s
A 0
B 1
C 2
dtype: int64
Drop labels B en C
>>> s.drop(labels=['B', 'C'])
A 0
dtype: int64
Drop 2nd level label in MultiIndex Series
>>> midx = pd.MultiIndex(levels=[['lama', 'cow', 'falcon'],
... ['speed', 'weight', 'length']],
... codes=[[0, 0, 0, 1, 1, 1, 2, 2, 2],
... [0, 1, 2, 0, 1, 2, 0, 1, 2]])
>>> s = pd.Series([45, 200, 1.2, 30, 250, 1.5, 320, 1, 0.3],
... index=midx)
>>> s
lama speed 45.0
weight 200.0
length 1.2
cow speed 30.0
weight 250.0
length 1.5
falcon speed 320.0
weight 1.0
length 0.3
dtype: float64
>>> s.drop(labels='weight', level=1)
lama speed 45.0
length 1.2
cow speed 30.0
length 1.5
falcon speed 320.0
length 0.3
dtype: float64
"""
return super().drop(
labels=labels,
axis=axis,
index=index,
columns=columns,
level=level,
inplace=inplace,
errors=errors,
)
@doc(NDFrame.fillna, **_shared_doc_kwargs)
def fillna(
self,
value=None,
method=None,
axis=None,
inplace=False,
limit=None,
downcast=None,
) -> Optional["Series"]:
return super().fillna(
value=value,
method=method,
axis=axis,
inplace=inplace,
limit=limit,
downcast=downcast,
)
@doc(NDFrame.replace, **_shared_doc_kwargs)
def replace(
self,
to_replace=None,
value=None,
inplace=False,
limit=None,
regex=False,
method="pad",
):
return super().replace(
to_replace=to_replace,
value=value,
inplace=inplace,
limit=limit,
regex=regex,
method=method,
)
@doc(NDFrame.shift, **_shared_doc_kwargs)
def shift(self, periods=1, freq=None, axis=0, fill_value=None) -> "Series":
return super().shift(
periods=periods, freq=freq, axis=axis, fill_value=fill_value
)
def memory_usage(self, index=True, deep=False):
"""
Return the memory usage of the Series.
The memory usage can optionally include the contribution of
the index and of elements of `object` dtype.
Parameters
----------
index : bool, default True
Specifies whether to include the memory usage of the Series index.
deep : bool, default False
If True, introspect the data deeply by interrogating
`object` dtypes for system-level memory consumption, and include
it in the returned value.
Returns
-------
int
Bytes of memory consumed.
See Also
--------
numpy.ndarray.nbytes : Total bytes consumed by the elements of the
array.
DataFrame.memory_usage : Bytes consumed by a DataFrame.
Examples
--------
>>> s = pd.Series(range(3))
>>> s.memory_usage()
152
Not including the index gives the size of the rest of the data, which
is necessarily smaller:
>>> s.memory_usage(index=False)
24
The memory footprint of `object` values is ignored by default:
>>> s = pd.Series(["a", "b"])
>>> s.values
array(['a', 'b'], dtype=object)
>>> s.memory_usage()
144
>>> s.memory_usage(deep=True)
260
"""
v = super().memory_usage(deep=deep)
if index:
v += self.index.memory_usage(deep=deep)
return v
def isin(self, values) -> "Series":
"""
Check whether `values` are contained in Series.
Return a boolean Series showing whether each element in the Series
matches an element in the passed sequence of `values` exactly.
Parameters
----------
values : set or list-like
The sequence of values to test. Passing in a single string will
raise a ``TypeError``. Instead, turn a single string into a
list of one element.
Returns
-------
Series
Series of booleans indicating if each element is in values.
Raises
------
TypeError
* If `values` is a string
See Also
--------
DataFrame.isin : Equivalent method on DataFrame.
Examples
--------
>>> s = pd.Series(['lama', 'cow', 'lama', 'beetle', 'lama',
... 'hippo'], name='animal')
>>> s.isin(['cow', 'lama'])
0 True
1 True
2 True
3 False
4 True
5 False
Name: animal, dtype: bool
Passing a single string as ``s.isin('lama')`` will raise an error. Use
a list of one element instead:
>>> s.isin(['lama'])
0 True
1 False
2 True
3 False
4 True
5 False
Name: animal, dtype: bool
"""
result = algorithms.isin(self, values)
return self._constructor(result, index=self.index).__finalize__(
self, method="isin"
)
def between(self, left, right, inclusive=True) -> "Series":
"""
Return boolean Series equivalent to left <= series <= right.
This function returns a boolean vector containing `True` wherever the
corresponding Series element is between the boundary values `left` and
`right`. NA values are treated as `False`.
Parameters
----------
left : scalar or list-like
Left boundary.
right : scalar or list-like
Right boundary.
inclusive : bool, default True
Include boundaries.
Returns
-------
Series
Series representing whether each element is between left and
right (inclusive).
See Also
--------
Series.gt : Greater than of series and other.
Series.lt : Less than of series and other.
Notes
-----
This function is equivalent to ``(left <= ser) & (ser <= right)``
Examples
--------
>>> s = pd.Series([2, 0, 4, 8, np.nan])
Boundary values are included by default:
>>> s.between(1, 4)
0 True
1 False
2 True
3 False
4 False
dtype: bool
With `inclusive` set to ``False`` boundary values are excluded:
>>> s.between(1, 4, inclusive=False)
0 True
1 False
2 False
3 False
4 False
dtype: bool
`left` and `right` can be any scalar value:
>>> s = pd.Series(['Alice', 'Bob', 'Carol', 'Eve'])
>>> s.between('Anna', 'Daniel')
0 False
1 True
2 True
3 False
dtype: bool
"""
if inclusive:
lmask = self >= left
rmask = self <= right
else:
lmask = self > left
rmask = self < right
return lmask & rmask
# ----------------------------------------------------------------------
# Convert to types that support pd.NA
def _convert_dtypes(
self,
infer_objects: bool = True,
convert_string: bool = True,
convert_integer: bool = True,
convert_boolean: bool = True,
) -> "Series":
input_series = self
if infer_objects:
input_series = input_series.infer_objects()
if is_object_dtype(input_series):
input_series = input_series.copy()
if convert_string or convert_integer or convert_boolean:
inferred_dtype = convert_dtypes(
input_series._values, convert_string, convert_integer, convert_boolean
)
try:
result = input_series.astype(inferred_dtype)
except TypeError:
result = input_series.copy()
else:
result = input_series.copy()
return result
@Appender(generic._shared_docs["isna"] % _shared_doc_kwargs)
def isna(self) -> "Series":
return super().isna()
@Appender(generic._shared_docs["isna"] % _shared_doc_kwargs)
def isnull(self) -> "Series":
return super().isnull()
@Appender(generic._shared_docs["notna"] % _shared_doc_kwargs)
def notna(self) -> "Series":
return super().notna()
@Appender(generic._shared_docs["notna"] % _shared_doc_kwargs)
def notnull(self) -> "Series":
return super().notnull()
def dropna(self, axis=0, inplace=False, how=None):
"""
Return a new Series with missing values removed.
See the :ref:`User Guide <missing_data>` for more on which values are
considered missing, and how to work with missing data.
Parameters
----------
axis : {0 or 'index'}, default 0
There is only one axis to drop values from.
inplace : bool, default False
If True, do operation inplace and return None.
how : str, optional
Not in use. Kept for compatibility.
Returns
-------
Series
Series with NA entries dropped from it.
See Also
--------
Series.isna: Indicate missing values.
Series.notna : Indicate existing (non-missing) values.
Series.fillna : Replace missing values.
DataFrame.dropna : Drop rows or columns which contain NA values.
Index.dropna : Drop missing indices.
Examples
--------
>>> ser = pd.Series([1., 2., np.nan])
>>> ser
0 1.0
1 2.0
2 NaN
dtype: float64
Drop NA values from a Series.
>>> ser.dropna()
0 1.0
1 2.0
dtype: float64
Keep the Series with valid entries in the same variable.
>>> ser.dropna(inplace=True)
>>> ser
0 1.0
1 2.0
dtype: float64
Empty strings are not considered NA values. ``None`` is considered an
NA value.
>>> ser = pd.Series([np.NaN, 2, pd.NaT, '', None, 'I stay'])
>>> ser
0 NaN
1 2
2 NaT
3
4 None
5 I stay
dtype: object
>>> ser.dropna()
1 2
3
5 I stay
dtype: object
"""
inplace = validate_bool_kwarg(inplace, "inplace")
# Validate the axis parameter
self._get_axis_number(axis or 0)
if self._can_hold_na:
result = remove_na_arraylike(self)
if inplace:
self._update_inplace(result)
else:
return result
else:
if inplace:
# do nothing
pass
else:
return self.copy()
# ----------------------------------------------------------------------
# Time series-oriented methods
def to_timestamp(self, freq=None, how="start", copy=True) -> "Series":
"""
Cast to DatetimeIndex of Timestamps, at *beginning* of period.
Parameters
----------
freq : str, default frequency of PeriodIndex
Desired frequency.
how : {'s', 'e', 'start', 'end'}
Convention for converting period to timestamp; start of period
vs. end.
copy : bool, default True
Whether or not to return a copy.
Returns
-------
Series with DatetimeIndex
"""
new_values = self._values
if copy:
new_values = new_values.copy()
assert isinstance(self.index, (ABCDatetimeIndex, ABCPeriodIndex))
new_index = self.index.to_timestamp(freq=freq, how=how)
return self._constructor(new_values, index=new_index).__finalize__(
self, method="to_timestamp"
)
def to_period(self, freq=None, copy=True) -> "Series":
"""
Convert Series from DatetimeIndex to PeriodIndex with desired
frequency (inferred from index if not passed).
Parameters
----------
freq : str, default None
Frequency associated with the PeriodIndex.
copy : bool, default True
Whether or not to return a copy.
Returns
-------
Series
Series with index converted to PeriodIndex.
"""
new_values = self._values
if copy:
new_values = new_values.copy()
assert isinstance(self.index, ABCDatetimeIndex)
new_index = self.index.to_period(freq=freq)
return self._constructor(new_values, index=new_index).__finalize__(
self, method="to_period"
)
# ----------------------------------------------------------------------
# Add index
_AXIS_ORDERS = ["index"]
_AXIS_NUMBERS = {"index": 0}
_AXIS_NAMES = {0: "index"}
_AXIS_REVERSED = False
_AXIS_LEN = len(_AXIS_ORDERS)
_info_axis_number = 0
_info_axis_name = "index"
index: "Index" = properties.AxisProperty(
axis=0, doc="The index (axis labels) of the Series."
)
# ----------------------------------------------------------------------
# Accessor Methods
# ----------------------------------------------------------------------
str = CachedAccessor("str", StringMethods)
dt = CachedAccessor("dt", CombinedDatetimelikeProperties)
cat = CachedAccessor("cat", CategoricalAccessor)
plot = CachedAccessor("plot", pandas.plotting.PlotAccessor)
sparse = CachedAccessor("sparse", SparseAccessor)
# ----------------------------------------------------------------------
# Add plotting methods to Series
hist = pandas.plotting.hist_series
Series._add_numeric_operations()
Series._add_series_or_dataframe_operations()
# Add arithmetic!
ops.add_flex_arithmetic_methods(Series)
ops.add_special_arithmetic_methods(Series)
| BugsInPy/BugsInPy/temp/projects/pandas/bug-21-fixed/pandas/pandas/core/series.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-21-buggy/pandas/pandas/core/series.py |
pandas-bug-124 | import codecs
from functools import wraps
import re
import textwrap
from typing import Dict, List
import warnings
import numpy as np
import pandas._libs.lib as lib
import pandas._libs.ops as libops
from pandas.util._decorators import Appender, deprecate_kwarg
from pandas.core.dtypes.common import (
ensure_object,
is_bool_dtype,
is_categorical_dtype,
is_integer,
is_list_like,
is_re,
is_scalar,
)
from pandas.core.dtypes.generic import (
ABCDataFrame,
ABCIndexClass,
ABCMultiIndex,
ABCSeries,
)
from pandas.core.dtypes.missing import isna
from pandas.core.algorithms import take_1d
from pandas.core.base import NoNewAttributesMixin
import pandas.core.common as com
_cpython_optimized_encoders = (
"utf-8",
"utf8",
"latin-1",
"latin1",
"iso-8859-1",
"mbcs",
"ascii",
)
_cpython_optimized_decoders = _cpython_optimized_encoders + ("utf-16", "utf-32")
_shared_docs = dict() # type: Dict[str, str]
def cat_core(list_of_columns: List, sep: str):
"""
Auxiliary function for :meth:`str.cat`
Parameters
----------
list_of_columns : list of numpy arrays
List of arrays to be concatenated with sep;
these arrays may not contain NaNs!
sep : string
The separator string for concatenating the columns.
Returns
-------
nd.array
The concatenation of list_of_columns with sep.
"""
if sep == "":
# no need to interleave sep if it is empty
return np.sum(list_of_columns, axis=0)
list_with_sep = [sep] * (2 * len(list_of_columns) - 1)
list_with_sep[::2] = list_of_columns
return np.sum(list_with_sep, axis=0)
def cat_safe(list_of_columns: List, sep: str):
"""
Auxiliary function for :meth:`str.cat`.
Same signature as cat_core, but handles TypeErrors in concatenation, which
happen if the arrays in list_of columns have the wrong dtypes or content.
Parameters
----------
list_of_columns : list of numpy arrays
List of arrays to be concatenated with sep;
these arrays may not contain NaNs!
sep : string
The separator string for concatenating the columns.
Returns
-------
nd.array
The concatenation of list_of_columns with sep.
"""
try:
result = cat_core(list_of_columns, sep)
except TypeError:
# if there are any non-string values (wrong dtype or hidden behind
# object dtype), np.sum will fail; catch and return with better message
for column in list_of_columns:
dtype = lib.infer_dtype(column, skipna=True)
if dtype not in ["string", "empty"]:
raise TypeError(
"Concatenation requires list-likes containing only "
"strings (or missing values). Offending values found in "
"column {}".format(dtype)
) from None
return result
def _na_map(f, arr, na_result=np.nan, dtype=object):
# should really _check_ for NA
return _map(f, arr, na_mask=True, na_value=na_result, dtype=dtype)
def _map(f, arr, na_mask=False, na_value=np.nan, dtype=object):
if not len(arr):
return np.ndarray(0, dtype=dtype)
if isinstance(arr, ABCSeries):
arr = arr.values
if not isinstance(arr, np.ndarray):
arr = np.asarray(arr, dtype=object)
if na_mask:
mask = isna(arr)
convert = not np.all(mask)
try:
result = lib.map_infer_mask(arr, f, mask.view(np.uint8), convert)
except (TypeError, AttributeError) as e:
# Reraise the exception if callable `f` got wrong number of args.
# The user may want to be warned by this, instead of getting NaN
p_err = (
r"((takes)|(missing)) (?(2)from \d+ to )?\d+ "
r"(?(3)required )positional arguments?"
)
if len(e.args) >= 1 and re.search(p_err, e.args[0]):
# FIXME: this should be totally avoidable
raise e
def g(x):
try:
return f(x)
except (TypeError, AttributeError):
return na_value
return _map(g, arr, dtype=dtype)
if na_value is not np.nan:
np.putmask(result, mask, na_value)
if result.dtype == object:
result = lib.maybe_convert_objects(result)
return result
else:
return lib.map_infer(arr, f)
def str_count(arr, pat, flags=0):
"""
Count occurrences of pattern in each string of the Series/Index.
This function is used to count the number of times a particular regex
pattern is repeated in each of the string elements of the
:class:`~pandas.Series`.
Parameters
----------
pat : str
Valid regular expression.
flags : int, default 0, meaning no flags
Flags for the `re` module. For a complete list, `see here
<https://docs.python.org/3/howto/regex.html#compilation-flags>`_.
**kwargs
For compatibility with other string methods. Not used.
Returns
-------
Series or Index
Same type as the calling object containing the integer counts.
See Also
--------
re : Standard library module for regular expressions.
str.count : Standard library version, without regular expression support.
Notes
-----
Some characters need to be escaped when passing in `pat`.
eg. ``'$'`` has a special meaning in regex and must be escaped when
finding this literal character.
Examples
--------
>>> s = pd.Series(['A', 'B', 'Aaba', 'Baca', np.nan, 'CABA', 'cat'])
>>> s.str.count('a')
0 0.0
1 0.0
2 2.0
3 2.0
4 NaN
5 0.0
6 1.0
dtype: float64
Escape ``'$'`` to find the literal dollar sign.
>>> s = pd.Series(['$', 'B', 'Aab$', '$$ca', 'C$B$', 'cat'])
>>> s.str.count('\\$')
0 1
1 0
2 1
3 2
4 2
5 0
dtype: int64
This is also available on Index
>>> pd.Index(['A', 'A', 'Aaba', 'cat']).str.count('a')
Int64Index([0, 0, 2, 1], dtype='int64')
"""
regex = re.compile(pat, flags=flags)
f = lambda x: len(regex.findall(x))
return _na_map(f, arr, dtype=int)
def str_contains(arr, pat, case=True, flags=0, na=np.nan, regex=True):
"""
Test if pattern or regex is contained within a string of a Series or Index.
Return boolean Series or Index based on whether a given pattern or regex is
contained within a string of a Series or Index.
Parameters
----------
pat : str
Character sequence or regular expression.
case : bool, default True
If True, case sensitive.
flags : int, default 0 (no flags)
Flags to pass through to the re module, e.g. re.IGNORECASE.
na : default NaN
Fill value for missing values.
regex : bool, default True
If True, assumes the pat is a regular expression.
If False, treats the pat as a literal string.
Returns
-------
Series or Index of boolean values
A Series or Index of boolean values indicating whether the
given pattern is contained within the string of each element
of the Series or Index.
See Also
--------
match : Analogous, but stricter, relying on re.match instead of re.search.
Series.str.startswith : Test if the start of each string element matches a
pattern.
Series.str.endswith : Same as startswith, but tests the end of string.
Examples
--------
Returning a Series of booleans using only a literal pattern.
>>> s1 = pd.Series(['Mouse', 'dog', 'house and parrot', '23', np.NaN])
>>> s1.str.contains('og', regex=False)
0 False
1 True
2 False
3 False
4 NaN
dtype: object
Returning an Index of booleans using only a literal pattern.
>>> ind = pd.Index(['Mouse', 'dog', 'house and parrot', '23.0', np.NaN])
>>> ind.str.contains('23', regex=False)
Index([False, False, False, True, nan], dtype='object')
Specifying case sensitivity using `case`.
>>> s1.str.contains('oG', case=True, regex=True)
0 False
1 False
2 False
3 False
4 NaN
dtype: object
Specifying `na` to be `False` instead of `NaN` replaces NaN values
with `False`. If Series or Index does not contain NaN values
the resultant dtype will be `bool`, otherwise, an `object` dtype.
>>> s1.str.contains('og', na=False, regex=True)
0 False
1 True
2 False
3 False
4 False
dtype: bool
Returning 'house' or 'dog' when either expression occurs in a string.
>>> s1.str.contains('house|dog', regex=True)
0 False
1 True
2 True
3 False
4 NaN
dtype: object
Ignoring case sensitivity using `flags` with regex.
>>> import re
>>> s1.str.contains('PARROT', flags=re.IGNORECASE, regex=True)
0 False
1 False
2 True
3 False
4 NaN
dtype: object
Returning any digit using regular expression.
>>> s1.str.contains('\\d', regex=True)
0 False
1 False
2 False
3 True
4 NaN
dtype: object
Ensure `pat` is a not a literal pattern when `regex` is set to True.
Note in the following example one might expect only `s2[1]` and `s2[3]` to
return `True`. However, '.0' as a regex matches any character
followed by a 0.
>>> s2 = pd.Series(['40', '40.0', '41', '41.0', '35'])
>>> s2.str.contains('.0', regex=True)
0 True
1 True
2 False
3 True
4 False
dtype: bool
"""
if regex:
if not case:
flags |= re.IGNORECASE
regex = re.compile(pat, flags=flags)
if regex.groups > 0:
warnings.warn(
"This pattern has match groups. To actually get the"
" groups, use str.extract.",
UserWarning,
stacklevel=3,
)
f = lambda x: bool(regex.search(x))
else:
if case:
f = lambda x: pat in x
else:
upper_pat = pat.upper()
f = lambda x: upper_pat in x
uppered = _na_map(lambda x: x.upper(), arr)
return _na_map(f, uppered, na, dtype=bool)
return _na_map(f, arr, na, dtype=bool)
def str_startswith(arr, pat, na=np.nan):
"""
Test if the start of each string element matches a pattern.
Equivalent to :meth:`str.startswith`.
Parameters
----------
pat : str
Character sequence. Regular expressions are not accepted.
na : object, default NaN
Object shown if element tested is not a string.
Returns
-------
Series or Index of bool
A Series of booleans indicating whether the given pattern matches
the start of each string element.
See Also
--------
str.startswith : Python standard library string method.
Series.str.endswith : Same as startswith, but tests the end of string.
Series.str.contains : Tests if string element contains a pattern.
Examples
--------
>>> s = pd.Series(['bat', 'Bear', 'cat', np.nan])
>>> s
0 bat
1 Bear
2 cat
3 NaN
dtype: object
>>> s.str.startswith('b')
0 True
1 False
2 False
3 NaN
dtype: object
Specifying `na` to be `False` instead of `NaN`.
>>> s.str.startswith('b', na=False)
0 True
1 False
2 False
3 False
dtype: bool
"""
f = lambda x: x.startswith(pat)
return _na_map(f, arr, na, dtype=bool)
def str_endswith(arr, pat, na=np.nan):
"""
Test if the end of each string element matches a pattern.
Equivalent to :meth:`str.endswith`.
Parameters
----------
pat : str
Character sequence. Regular expressions are not accepted.
na : object, default NaN
Object shown if element tested is not a string.
Returns
-------
Series or Index of bool
A Series of booleans indicating whether the given pattern matches
the end of each string element.
See Also
--------
str.endswith : Python standard library string method.
Series.str.startswith : Same as endswith, but tests the start of string.
Series.str.contains : Tests if string element contains a pattern.
Examples
--------
>>> s = pd.Series(['bat', 'bear', 'caT', np.nan])
>>> s
0 bat
1 bear
2 caT
3 NaN
dtype: object
>>> s.str.endswith('t')
0 True
1 False
2 False
3 NaN
dtype: object
Specifying `na` to be `False` instead of `NaN`.
>>> s.str.endswith('t', na=False)
0 True
1 False
2 False
3 False
dtype: bool
"""
f = lambda x: x.endswith(pat)
return _na_map(f, arr, na, dtype=bool)
def str_replace(arr, pat, repl, n=-1, case=None, flags=0, regex=True):
r"""
Replace occurrences of pattern/regex in the Series/Index with
some other string. Equivalent to :meth:`str.replace` or
:func:`re.sub`.
Parameters
----------
pat : str or compiled regex
String can be a character sequence or regular expression.
repl : str or callable
Replacement string or a callable. The callable is passed the regex
match object and must return a replacement string to be used.
See :func:`re.sub`.
n : int, default -1 (all)
Number of replacements to make from start.
case : bool, default None
Determines if replace is case sensitive:
- If True, case sensitive (the default if `pat` is a string)
- Set to False for case insensitive
- Cannot be set if `pat` is a compiled regex.
flags : int, default 0 (no flags)
Regex module flags, e.g. re.IGNORECASE. Cannot be set if `pat` is a compiled
regex.
regex : bool, default True
Determines if assumes the passed-in pattern is a regular expression:
- If True, assumes the passed-in pattern is a regular expression.
- If False, treats the pattern as a literal string
- Cannot be set to False if `pat` is a compiled regex or `repl` is
a callable.
.. versionadded:: 0.23.0
Returns
-------
Series or Index of object
A copy of the object with all matching occurrences of `pat` replaced by
`repl`.
Raises
------
ValueError
* if `regex` is False and `repl` is a callable or `pat` is a compiled
regex
* if `pat` is a compiled regex and `case` or `flags` is set
Notes
-----
When `pat` is a compiled regex, all flags should be included in the
compiled regex. Use of `case`, `flags`, or `regex=False` with a compiled
regex will raise an error.
Examples
--------
When `pat` is a string and `regex` is True (the default), the given `pat`
is compiled as a regex. When `repl` is a string, it replaces matching
regex patterns as with :meth:`re.sub`. NaN value(s) in the Series are
left as is:
>>> pd.Series(['foo', 'fuz', np.nan]).str.replace('f.', 'ba', regex=True)
0 bao
1 baz
2 NaN
dtype: object
When `pat` is a string and `regex` is False, every `pat` is replaced with
`repl` as with :meth:`str.replace`:
>>> pd.Series(['f.o', 'fuz', np.nan]).str.replace('f.', 'ba', regex=False)
0 bao
1 fuz
2 NaN
dtype: object
When `repl` is a callable, it is called on every `pat` using
:func:`re.sub`. The callable should expect one positional argument
(a regex object) and return a string.
To get the idea:
>>> pd.Series(['foo', 'fuz', np.nan]).str.replace('f', repr)
0 <_sre.SRE_Match object; span=(0, 1), match='f'>oo
1 <_sre.SRE_Match object; span=(0, 1), match='f'>uz
2 NaN
dtype: object
Reverse every lowercase alphabetic word:
>>> repl = lambda m: m.group(0)[::-1]
>>> pd.Series(['foo 123', 'bar baz', np.nan]).str.replace(r'[a-z]+', repl)
0 oof 123
1 rab zab
2 NaN
dtype: object
Using regex groups (extract second group and swap case):
>>> pat = r"(?P<one>\w+) (?P<two>\w+) (?P<three>\w+)"
>>> repl = lambda m: m.group('two').swapcase()
>>> pd.Series(['One Two Three', 'Foo Bar Baz']).str.replace(pat, repl)
0 tWO
1 bAR
dtype: object
Using a compiled regex with flags
>>> import re
>>> regex_pat = re.compile(r'FUZ', flags=re.IGNORECASE)
>>> pd.Series(['foo', 'fuz', np.nan]).str.replace(regex_pat, 'bar')
0 foo
1 bar
2 NaN
dtype: object
"""
# Check whether repl is valid (GH 13438, GH 15055)
if not (isinstance(repl, str) or callable(repl)):
raise TypeError("repl must be a string or callable")
is_compiled_re = is_re(pat)
if regex:
if is_compiled_re:
if (case is not None) or (flags != 0):
raise ValueError(
"case and flags cannot be set when pat is a compiled regex"
)
else:
# not a compiled regex
# set default case
if case is None:
case = True
# add case flag, if provided
if case is False:
flags |= re.IGNORECASE
if is_compiled_re or len(pat) > 1 or flags or callable(repl):
n = n if n >= 0 else 0
compiled = re.compile(pat, flags=flags)
f = lambda x: compiled.sub(repl=repl, string=x, count=n)
else:
f = lambda x: x.replace(pat, repl, n)
else:
if is_compiled_re:
raise ValueError(
"Cannot use a compiled regex as replacement pattern with regex=False"
)
if callable(repl):
raise ValueError("Cannot use a callable replacement when regex=False")
f = lambda x: x.replace(pat, repl, n)
return _na_map(f, arr)
def str_repeat(arr, repeats):
"""
Duplicate each string in the Series or Index.
Parameters
----------
repeats : int or sequence of int
Same value for all (int) or different value per (sequence).
Returns
-------
Series or Index of object
Series or Index of repeated string objects specified by
input parameter repeats.
Examples
--------
>>> s = pd.Series(['a', 'b', 'c'])
>>> s
0 a
1 b
2 c
dtype: object
Single int repeats string in Series
>>> s.str.repeat(repeats=2)
0 aa
1 bb
2 cc
dtype: object
Sequence of int repeats corresponding string in Series
>>> s.str.repeat(repeats=[1, 2, 3])
0 a
1 bb
2 ccc
dtype: object
"""
if is_scalar(repeats):
def scalar_rep(x):
try:
return bytes.__mul__(x, repeats)
except TypeError:
return str.__mul__(x, repeats)
return _na_map(scalar_rep, arr)
else:
def rep(x, r):
try:
return bytes.__mul__(x, r)
except TypeError:
return str.__mul__(x, r)
repeats = np.asarray(repeats, dtype=object)
result = libops.vec_binop(com.values_from_object(arr), repeats, rep)
return result
def str_match(arr, pat, case=True, flags=0, na=np.nan):
"""
Determine if each string matches a regular expression.
Parameters
----------
pat : str
Character sequence or regular expression.
case : bool, default True
If True, case sensitive.
flags : int, default 0 (no flags)
Regex module flags, e.g. re.IGNORECASE.
na : default NaN
Fill value for missing values.
Returns
-------
Series/array of boolean values
See Also
--------
contains : Analogous, but less strict, relying on re.search instead of
re.match.
extract : Extract matched groups.
"""
if not case:
flags |= re.IGNORECASE
regex = re.compile(pat, flags=flags)
dtype = bool
f = lambda x: bool(regex.match(x))
return _na_map(f, arr, na, dtype=dtype)
def _get_single_group_name(rx):
try:
return list(rx.groupindex.keys()).pop()
except IndexError:
return None
def _groups_or_na_fun(regex):
"""Used in both extract_noexpand and extract_frame"""
if regex.groups == 0:
raise ValueError("pattern contains no capture groups")
empty_row = [np.nan] * regex.groups
def f(x):
if not isinstance(x, str):
return empty_row
m = regex.search(x)
if m:
return [np.nan if item is None else item for item in m.groups()]
else:
return empty_row
return f
def _result_dtype(arr):
# workaround #27953
# ideally we just pass `dtype=arr.dtype` unconditionally, but this fails
# when the list of values is empty.
if arr.dtype.name == "string":
return "string"
else:
return object
def _str_extract_noexpand(arr, pat, flags=0):
"""
Find groups in each string in the Series using passed regular
expression. This function is called from
str_extract(expand=False), and can return Series, DataFrame, or
Index.
"""
from pandas import DataFrame
regex = re.compile(pat, flags=flags)
groups_or_na = _groups_or_na_fun(regex)
if regex.groups == 1:
result = np.array([groups_or_na(val)[0] for val in arr], dtype=object)
name = _get_single_group_name(regex)
else:
if isinstance(arr, ABCIndexClass):
raise ValueError("only one regex group is supported with Index")
name = None
names = dict(zip(regex.groupindex.values(), regex.groupindex.keys()))
columns = [names.get(1 + i, i) for i in range(regex.groups)]
if arr.empty:
result = DataFrame(columns=columns, dtype=object)
else:
result = DataFrame(
[groups_or_na(val) for val in arr],
columns=columns,
index=arr.index,
dtype=object,
)
return result, name
def _str_extract_frame(arr, pat, flags=0):
"""
For each subject string in the Series, extract groups from the
first match of regular expression pat. This function is called from
str_extract(expand=True), and always returns a DataFrame.
"""
from pandas import DataFrame
regex = re.compile(pat, flags=flags)
groups_or_na = _groups_or_na_fun(regex)
names = dict(zip(regex.groupindex.values(), regex.groupindex.keys()))
columns = [names.get(1 + i, i) for i in range(regex.groups)]
if len(arr) == 0:
return DataFrame(columns=columns, dtype=object)
try:
result_index = arr.index
except AttributeError:
result_index = None
dtype = _result_dtype(arr)
return DataFrame(
[groups_or_na(val) for val in arr],
columns=columns,
index=result_index,
dtype=dtype,
)
def str_extract(arr, pat, flags=0, expand=True):
r"""
Extract capture groups in the regex `pat` as columns in a DataFrame.
For each subject string in the Series, extract groups from the
first match of regular expression `pat`.
Parameters
----------
pat : str
Regular expression pattern with capturing groups.
flags : int, default 0 (no flags)
Flags from the ``re`` module, e.g. ``re.IGNORECASE``, that
modify regular expression matching for things like case,
spaces, etc. For more details, see :mod:`re`.
expand : bool, default True
If True, return DataFrame with one column per capture group.
If False, return a Series/Index if there is one capture group
or DataFrame if there are multiple capture groups.
Returns
-------
DataFrame or Series or Index
A DataFrame with one row for each subject string, and one
column for each group. Any capture group names in regular
expression pat will be used for column names; otherwise
capture group numbers will be used. The dtype of each result
column is always object, even when no match is found. If
``expand=False`` and pat has only one capture group, then
return a Series (if subject is a Series) or Index (if subject
is an Index).
See Also
--------
extractall : Returns all matches (not just the first match).
Examples
--------
A pattern with two groups will return a DataFrame with two columns.
Non-matches will be NaN.
>>> s = pd.Series(['a1', 'b2', 'c3'])
>>> s.str.extract(r'([ab])(\d)')
0 1
0 a 1
1 b 2
2 NaN NaN
A pattern may contain optional groups.
>>> s.str.extract(r'([ab])?(\d)')
0 1
0 a 1
1 b 2
2 NaN 3
Named groups will become column names in the result.
>>> s.str.extract(r'(?P<letter>[ab])(?P<digit>\d)')
letter digit
0 a 1
1 b 2
2 NaN NaN
A pattern with one group will return a DataFrame with one column
if expand=True.
>>> s.str.extract(r'[ab](\d)', expand=True)
0
0 1
1 2
2 NaN
A pattern with one group will return a Series if expand=False.
>>> s.str.extract(r'[ab](\d)', expand=False)
0 1
1 2
2 NaN
dtype: object
"""
if not isinstance(expand, bool):
raise ValueError("expand must be True or False")
if expand:
return _str_extract_frame(arr._orig, pat, flags=flags)
else:
result, name = _str_extract_noexpand(arr._parent, pat, flags=flags)
return arr._wrap_result(result, name=name, expand=expand)
def str_extractall(arr, pat, flags=0):
r"""
For each subject string in the Series, extract groups from all
matches of regular expression pat. When each subject string in the
Series has exactly one match, extractall(pat).xs(0, level='match')
is the same as extract(pat).
Parameters
----------
pat : str
Regular expression pattern with capturing groups.
flags : int, default 0 (no flags)
A ``re`` module flag, for example ``re.IGNORECASE``. These allow
to modify regular expression matching for things like case, spaces,
etc. Multiple flags can be combined with the bitwise OR operator,
for example ``re.IGNORECASE | re.MULTILINE``.
Returns
-------
DataFrame
A ``DataFrame`` with one row for each match, and one column for each
group. Its rows have a ``MultiIndex`` with first levels that come from
the subject ``Series``. The last level is named 'match' and indexes the
matches in each item of the ``Series``. Any capture group names in
regular expression pat will be used for column names; otherwise capture
group numbers will be used.
See Also
--------
extract : Returns first match only (not all matches).
Examples
--------
A pattern with one group will return a DataFrame with one column.
Indices with no matches will not appear in the result.
>>> s = pd.Series(["a1a2", "b1", "c1"], index=["A", "B", "C"])
>>> s.str.extractall(r"[ab](\d)")
0
match
A 0 1
1 2
B 0 1
Capture group names are used for column names of the result.
>>> s.str.extractall(r"[ab](?P<digit>\d)")
digit
match
A 0 1
1 2
B 0 1
A pattern with two groups will return a DataFrame with two columns.
>>> s.str.extractall(r"(?P<letter>[ab])(?P<digit>\d)")
letter digit
match
A 0 a 1
1 a 2
B 0 b 1
Optional groups that do not match are NaN in the result.
>>> s.str.extractall(r"(?P<letter>[ab])?(?P<digit>\d)")
letter digit
match
A 0 a 1
1 a 2
B 0 b 1
C 0 NaN 1
"""
regex = re.compile(pat, flags=flags)
# the regex must contain capture groups.
if regex.groups == 0:
raise ValueError("pattern contains no capture groups")
if isinstance(arr, ABCIndexClass):
arr = arr.to_series().reset_index(drop=True)
names = dict(zip(regex.groupindex.values(), regex.groupindex.keys()))
columns = [names.get(1 + i, i) for i in range(regex.groups)]
match_list = []
index_list = []
is_mi = arr.index.nlevels > 1
for subject_key, subject in arr.items():
if isinstance(subject, str):
if not is_mi:
subject_key = (subject_key,)
for match_i, match_tuple in enumerate(regex.findall(subject)):
if isinstance(match_tuple, str):
match_tuple = (match_tuple,)
na_tuple = [np.NaN if group == "" else group for group in match_tuple]
match_list.append(na_tuple)
result_key = tuple(subject_key + (match_i,))
index_list.append(result_key)
from pandas import MultiIndex
index = MultiIndex.from_tuples(index_list, names=arr.index.names + ["match"])
dtype = _result_dtype(arr)
result = arr._constructor_expanddim(
match_list, index=index, columns=columns, dtype=dtype
)
return result
def str_get_dummies(arr, sep="|"):
"""
Split each string in the Series by sep and return a DataFrame
of dummy/indicator variables.
Parameters
----------
sep : str, default "|"
String to split on.
Returns
-------
DataFrame
Dummy variables corresponding to values of the Series.
See Also
--------
get_dummies : Convert categorical variable into dummy/indicator
variables.
Examples
--------
>>> pd.Series(['a|b', 'a', 'a|c']).str.get_dummies()
a b c
0 1 1 0
1 1 0 0
2 1 0 1
>>> pd.Series(['a|b', np.nan, 'a|c']).str.get_dummies()
a b c
0 1 1 0
1 0 0 0
2 1 0 1
"""
arr = arr.fillna("")
try:
arr = sep + arr + sep
except TypeError:
arr = sep + arr.astype(str) + sep
tags = set()
for ts in arr.str.split(sep):
tags.update(ts)
tags = sorted(tags - {""})
dummies = np.empty((len(arr), len(tags)), dtype=np.int64)
for i, t in enumerate(tags):
pat = sep + t + sep
dummies[:, i] = lib.map_infer(arr.to_numpy(), lambda x: pat in x)
return dummies, tags
def str_join(arr, sep):
"""
Join lists contained as elements in the Series/Index with passed delimiter.
If the elements of a Series are lists themselves, join the content of these
lists using the delimiter passed to the function.
This function is an equivalent to :meth:`str.join`.
Parameters
----------
sep : str
Delimiter to use between list entries.
Returns
-------
Series/Index: object
The list entries concatenated by intervening occurrences of the
delimiter.
Raises
------
AttributeError
If the supplied Series contains neither strings nor lists.
See Also
--------
str.join : Standard library version of this method.
Series.str.split : Split strings around given separator/delimiter.
Notes
-----
If any of the list items is not a string object, the result of the join
will be `NaN`.
Examples
--------
Example with a list that contains non-string elements.
>>> s = pd.Series([['lion', 'elephant', 'zebra'],
... [1.1, 2.2, 3.3],
... ['cat', np.nan, 'dog'],
... ['cow', 4.5, 'goat'],
... ['duck', ['swan', 'fish'], 'guppy']])
>>> s
0 [lion, elephant, zebra]
1 [1.1, 2.2, 3.3]
2 [cat, nan, dog]
3 [cow, 4.5, goat]
4 [duck, [swan, fish], guppy]
dtype: object
Join all lists using a '-'. The lists containing object(s) of types other
than str will produce a NaN.
>>> s.str.join('-')
0 lion-elephant-zebra
1 NaN
2 NaN
3 NaN
4 NaN
dtype: object
"""
return _na_map(sep.join, arr)
def str_findall(arr, pat, flags=0):
"""
Find all occurrences of pattern or regular expression in the Series/Index.
Equivalent to applying :func:`re.findall` to all the elements in the
Series/Index.
Parameters
----------
pat : str
Pattern or regular expression.
flags : int, default 0
Flags from ``re`` module, e.g. `re.IGNORECASE` (default is 0, which
means no flags).
Returns
-------
Series/Index of lists of strings
All non-overlapping matches of pattern or regular expression in each
string of this Series/Index.
See Also
--------
count : Count occurrences of pattern or regular expression in each string
of the Series/Index.
extractall : For each string in the Series, extract groups from all matches
of regular expression and return a DataFrame with one row for each
match and one column for each group.
re.findall : The equivalent ``re`` function to all non-overlapping matches
of pattern or regular expression in string, as a list of strings.
Examples
--------
>>> s = pd.Series(['Lion', 'Monkey', 'Rabbit'])
The search for the pattern 'Monkey' returns one match:
>>> s.str.findall('Monkey')
0 []
1 [Monkey]
2 []
dtype: object
On the other hand, the search for the pattern 'MONKEY' doesn't return any
match:
>>> s.str.findall('MONKEY')
0 []
1 []
2 []
dtype: object
Flags can be added to the pattern or regular expression. For instance,
to find the pattern 'MONKEY' ignoring the case:
>>> import re
>>> s.str.findall('MONKEY', flags=re.IGNORECASE)
0 []
1 [Monkey]
2 []
dtype: object
When the pattern matches more than one string in the Series, all matches
are returned:
>>> s.str.findall('on')
0 [on]
1 [on]
2 []
dtype: object
Regular expressions are supported too. For instance, the search for all the
strings ending with the word 'on' is shown next:
>>> s.str.findall('on$')
0 [on]
1 []
2 []
dtype: object
If the pattern is found more than once in the same string, then a list of
multiple strings is returned:
>>> s.str.findall('b')
0 []
1 []
2 [b, b]
dtype: object
"""
regex = re.compile(pat, flags=flags)
return _na_map(regex.findall, arr)
def str_find(arr, sub, start=0, end=None, side="left"):
"""
Return indexes in each strings in the Series/Index where the
substring is fully contained between [start:end]. Return -1 on failure.
Parameters
----------
sub : str
Substring being searched.
start : int
Left edge index.
end : int
Right edge index.
side : {'left', 'right'}, default 'left'
Specifies a starting side, equivalent to ``find`` or ``rfind``.
Returns
-------
Series or Index
Indexes where substring is found.
"""
if not isinstance(sub, str):
msg = "expected a string object, not {0}"
raise TypeError(msg.format(type(sub).__name__))
if side == "left":
method = "find"
elif side == "right":
method = "rfind"
else: # pragma: no cover
raise ValueError("Invalid side")
if end is None:
f = lambda x: getattr(x, method)(sub, start)
else:
f = lambda x: getattr(x, method)(sub, start, end)
return _na_map(f, arr, dtype=int)
def str_index(arr, sub, start=0, end=None, side="left"):
if not isinstance(sub, str):
msg = "expected a string object, not {0}"
raise TypeError(msg.format(type(sub).__name__))
if side == "left":
method = "index"
elif side == "right":
method = "rindex"
else: # pragma: no cover
raise ValueError("Invalid side")
if end is None:
f = lambda x: getattr(x, method)(sub, start)
else:
f = lambda x: getattr(x, method)(sub, start, end)
return _na_map(f, arr, dtype=int)
def str_pad(arr, width, side="left", fillchar=" "):
"""
Pad strings in the Series/Index up to width.
Parameters
----------
width : int
Minimum width of resulting string; additional characters will be filled
with character defined in `fillchar`.
side : {'left', 'right', 'both'}, default 'left'
Side from which to fill resulting string.
fillchar : str, default ' '
Additional character for filling, default is whitespace.
Returns
-------
Series or Index of object
Returns Series or Index with minimum number of char in object.
See Also
--------
Series.str.rjust : Fills the left side of strings with an arbitrary
character. Equivalent to ``Series.str.pad(side='left')``.
Series.str.ljust : Fills the right side of strings with an arbitrary
character. Equivalent to ``Series.str.pad(side='right')``.
Series.str.center : Fills boths sides of strings with an arbitrary
character. Equivalent to ``Series.str.pad(side='both')``.
Series.str.zfill : Pad strings in the Series/Index by prepending '0'
character. Equivalent to ``Series.str.pad(side='left', fillchar='0')``.
Examples
--------
>>> s = pd.Series(["caribou", "tiger"])
>>> s
0 caribou
1 tiger
dtype: object
>>> s.str.pad(width=10)
0 caribou
1 tiger
dtype: object
>>> s.str.pad(width=10, side='right', fillchar='-')
0 caribou---
1 tiger-----
dtype: object
>>> s.str.pad(width=10, side='both', fillchar='-')
0 -caribou--
1 --tiger---
dtype: object
"""
if not isinstance(fillchar, str):
msg = "fillchar must be a character, not {0}"
raise TypeError(msg.format(type(fillchar).__name__))
if len(fillchar) != 1:
raise TypeError("fillchar must be a character, not str")
if not is_integer(width):
msg = "width must be of integer type, not {0}"
raise TypeError(msg.format(type(width).__name__))
if side == "left":
f = lambda x: x.rjust(width, fillchar)
elif side == "right":
f = lambda x: x.ljust(width, fillchar)
elif side == "both":
f = lambda x: x.center(width, fillchar)
else: # pragma: no cover
raise ValueError("Invalid side")
return _na_map(f, arr)
def str_split(arr, pat=None, n=None):
if pat is None:
if n is None or n == 0:
n = -1
f = lambda x: x.split(pat, n)
else:
if len(pat) == 1:
if n is None or n == 0:
n = -1
f = lambda x: x.split(pat, n)
else:
if n is None or n == -1:
n = 0
regex = re.compile(pat)
f = lambda x: regex.split(x, maxsplit=n)
res = _na_map(f, arr)
return res
def str_rsplit(arr, pat=None, n=None):
if n is None or n == 0:
n = -1
f = lambda x: x.rsplit(pat, n)
res = _na_map(f, arr)
return res
def str_slice(arr, start=None, stop=None, step=None):
"""
Slice substrings from each element in the Series or Index.
Parameters
----------
start : int, optional
Start position for slice operation.
stop : int, optional
Stop position for slice operation.
step : int, optional
Step size for slice operation.
Returns
-------
Series or Index of object
Series or Index from sliced substring from original string object.
See Also
--------
Series.str.slice_replace : Replace a slice with a string.
Series.str.get : Return element at position.
Equivalent to `Series.str.slice(start=i, stop=i+1)` with `i`
being the position.
Examples
--------
>>> s = pd.Series(["koala", "fox", "chameleon"])
>>> s
0 koala
1 fox
2 chameleon
dtype: object
>>> s.str.slice(start=1)
0 oala
1 ox
2 hameleon
dtype: object
>>> s.str.slice(start=-1)
0 a
1 x
2 n
dtype: object
>>> s.str.slice(stop=2)
0 ko
1 fo
2 ch
dtype: object
>>> s.str.slice(step=2)
0 kaa
1 fx
2 caeen
dtype: object
>>> s.str.slice(start=0, stop=5, step=3)
0 kl
1 f
2 cm
dtype: object
Equivalent behaviour to:
>>> s.str[0:5:3]
0 kl
1 f
2 cm
dtype: object
"""
obj = slice(start, stop, step)
f = lambda x: x[obj]
return _na_map(f, arr)
def str_slice_replace(arr, start=None, stop=None, repl=None):
"""
Replace a positional slice of a string with another value.
Parameters
----------
start : int, optional
Left index position to use for the slice. If not specified (None),
the slice is unbounded on the left, i.e. slice from the start
of the string.
stop : int, optional
Right index position to use for the slice. If not specified (None),
the slice is unbounded on the right, i.e. slice until the
end of the string.
repl : str, optional
String for replacement. If not specified (None), the sliced region
is replaced with an empty string.
Returns
-------
Series or Index
Same type as the original object.
See Also
--------
Series.str.slice : Just slicing without replacement.
Examples
--------
>>> s = pd.Series(['a', 'ab', 'abc', 'abdc', 'abcde'])
>>> s
0 a
1 ab
2 abc
3 abdc
4 abcde
dtype: object
Specify just `start`, meaning replace `start` until the end of the
string with `repl`.
>>> s.str.slice_replace(1, repl='X')
0 aX
1 aX
2 aX
3 aX
4 aX
dtype: object
Specify just `stop`, meaning the start of the string to `stop` is replaced
with `repl`, and the rest of the string is included.
>>> s.str.slice_replace(stop=2, repl='X')
0 X
1 X
2 Xc
3 Xdc
4 Xcde
dtype: object
Specify `start` and `stop`, meaning the slice from `start` to `stop` is
replaced with `repl`. Everything before or after `start` and `stop` is
included as is.
>>> s.str.slice_replace(start=1, stop=3, repl='X')
0 aX
1 aX
2 aX
3 aXc
4 aXde
dtype: object
"""
if repl is None:
repl = ""
def f(x):
if x[start:stop] == "":
local_stop = start
else:
local_stop = stop
y = ""
if start is not None:
y += x[:start]
y += repl
if stop is not None:
y += x[local_stop:]
return y
return _na_map(f, arr)
def str_strip(arr, to_strip=None, side="both"):
"""
Strip whitespace (including newlines) from each string in the
Series/Index.
Parameters
----------
to_strip : str or unicode
side : {'left', 'right', 'both'}, default 'both'
Returns
-------
Series or Index
"""
if side == "both":
f = lambda x: x.strip(to_strip)
elif side == "left":
f = lambda x: x.lstrip(to_strip)
elif side == "right":
f = lambda x: x.rstrip(to_strip)
else: # pragma: no cover
raise ValueError("Invalid side")
return _na_map(f, arr)
def str_wrap(arr, width, **kwargs):
r"""
Wrap long strings in the Series/Index to be formatted in
paragraphs with length less than a given width.
This method has the same keyword parameters and defaults as
:class:`textwrap.TextWrapper`.
Parameters
----------
width : int
Maximum line width.
expand_tabs : bool, optional
If True, tab characters will be expanded to spaces (default: True).
replace_whitespace : bool, optional
If True, each whitespace character (as defined by string.whitespace)
remaining after tab expansion will be replaced by a single space
(default: True).
drop_whitespace : bool, optional
If True, whitespace that, after wrapping, happens to end up at the
beginning or end of a line is dropped (default: True).
break_long_words : bool, optional
If True, then words longer than width will be broken in order to ensure
that no lines are longer than width. If it is false, long words will
not be broken, and some lines may be longer than width (default: True).
break_on_hyphens : bool, optional
If True, wrapping will occur preferably on whitespace and right after
hyphens in compound words, as it is customary in English. If false,
only whitespaces will be considered as potentially good places for line
breaks, but you need to set break_long_words to false if you want truly
insecable words (default: True).
Returns
-------
Series or Index
Notes
-----
Internally, this method uses a :class:`textwrap.TextWrapper` instance with
default settings. To achieve behavior matching R's stringr library str_wrap
function, use the arguments:
- expand_tabs = False
- replace_whitespace = True
- drop_whitespace = True
- break_long_words = False
- break_on_hyphens = False
Examples
--------
>>> s = pd.Series(['line to be wrapped', 'another line to be wrapped'])
>>> s.str.wrap(12)
0 line to be\nwrapped
1 another line\nto be\nwrapped
dtype: object
"""
kwargs["width"] = width
tw = textwrap.TextWrapper(**kwargs)
return _na_map(lambda s: "\n".join(tw.wrap(s)), arr)
def str_translate(arr, table):
"""
Map all characters in the string through the given mapping table.
Equivalent to standard :meth:`str.translate`.
Parameters
----------
table : dict
Table is a mapping of Unicode ordinals to Unicode ordinals, strings, or
None. Unmapped characters are left untouched.
Characters mapped to None are deleted. :meth:`str.maketrans` is a
helper function for making translation tables.
Returns
-------
Series or Index
"""
return _na_map(lambda x: x.translate(table), arr)
def str_get(arr, i):
"""
Extract element from each component at specified position.
Extract element from lists, tuples, or strings in each element in the
Series/Index.
Parameters
----------
i : int
Position of element to extract.
Returns
-------
Series or Index
Examples
--------
>>> s = pd.Series(["String",
... (1, 2, 3),
... ["a", "b", "c"],
... 123,
... -456,
... {1: "Hello", "2": "World"}])
>>> s
0 String
1 (1, 2, 3)
2 [a, b, c]
3 123
4 -456
5 {1: 'Hello', '2': 'World'}
dtype: object
>>> s.str.get(1)
0 t
1 2
2 b
3 NaN
4 NaN
5 Hello
dtype: object
>>> s.str.get(-1)
0 g
1 3
2 c
3 NaN
4 NaN
5 None
dtype: object
"""
def f(x):
if isinstance(x, dict):
return x.get(i)
elif len(x) > i >= -len(x):
return x[i]
return np.nan
return _na_map(f, arr)
def str_decode(arr, encoding, errors="strict"):
"""
Decode character string in the Series/Index using indicated encoding.
Equivalent to :meth:`str.decode` in python2 and :meth:`bytes.decode` in
python3.
Parameters
----------
encoding : str
errors : str, optional
Returns
-------
Series or Index
"""
if encoding in _cpython_optimized_decoders:
# CPython optimized implementation
f = lambda x: x.decode(encoding, errors)
else:
decoder = codecs.getdecoder(encoding)
f = lambda x: decoder(x, errors)[0]
return _na_map(f, arr)
def str_encode(arr, encoding, errors="strict"):
"""
Encode character string in the Series/Index using indicated encoding.
Equivalent to :meth:`str.encode`.
Parameters
----------
encoding : str
errors : str, optional
Returns
-------
encoded : Series/Index of objects
"""
if encoding in _cpython_optimized_encoders:
# CPython optimized implementation
f = lambda x: x.encode(encoding, errors)
else:
encoder = codecs.getencoder(encoding)
f = lambda x: encoder(x, errors)[0]
return _na_map(f, arr)
def forbid_nonstring_types(forbidden, name=None):
"""
Decorator to forbid specific types for a method of StringMethods.
For calling `.str.{method}` on a Series or Index, it is necessary to first
initialize the :class:`StringMethods` object, and then call the method.
However, different methods allow different input types, and so this can not
be checked during :meth:`StringMethods.__init__`, but must be done on a
per-method basis. This decorator exists to facilitate this process, and
make it explicit which (inferred) types are disallowed by the method.
:meth:`StringMethods.__init__` allows the *union* of types its different
methods allow (after skipping NaNs; see :meth:`StringMethods._validate`),
namely: ['string', 'empty', 'bytes', 'mixed', 'mixed-integer'].
The default string types ['string', 'empty'] are allowed for all methods.
For the additional types ['bytes', 'mixed', 'mixed-integer'], each method
then needs to forbid the types it is not intended for.
Parameters
----------
forbidden : list-of-str or None
List of forbidden non-string types, may be one or more of
`['bytes', 'mixed', 'mixed-integer']`.
name : str, default None
Name of the method to use in the error message. By default, this is
None, in which case the name from the method being wrapped will be
copied. However, for working with further wrappers (like _pat_wrapper
and _noarg_wrapper), it is necessary to specify the name.
Returns
-------
func : wrapper
The method to which the decorator is applied, with an added check that
enforces the inferred type to not be in the list of forbidden types.
Raises
------
TypeError
If the inferred type of the underlying data is in `forbidden`.
"""
# deal with None
forbidden = [] if forbidden is None else forbidden
allowed_types = {"string", "empty", "bytes", "mixed", "mixed-integer"} - set(
forbidden
)
def _forbid_nonstring_types(func):
func_name = func.__name__ if name is None else name
@wraps(func)
def wrapper(self, *args, **kwargs):
if self._inferred_dtype not in allowed_types:
msg = (
"Cannot use .str.{name} with values of inferred dtype "
"{inf_type!r}.".format(
name=func_name, inf_type=self._inferred_dtype
)
)
raise TypeError(msg)
return func(self, *args, **kwargs)
wrapper.__name__ = func_name
return wrapper
return _forbid_nonstring_types
def _noarg_wrapper(
f,
name=None,
docstring=None,
forbidden_types=["bytes"],
returns_string=True,
**kargs,
):
@forbid_nonstring_types(forbidden_types, name=name)
def wrapper(self):
result = _na_map(f, self._parent, **kargs)
return self._wrap_result(result, returns_string=returns_string)
wrapper.__name__ = f.__name__ if name is None else name
if docstring is not None:
wrapper.__doc__ = docstring
else:
raise ValueError("Provide docstring")
return wrapper
def _pat_wrapper(
f,
flags=False,
na=False,
name=None,
forbidden_types=["bytes"],
returns_string=True,
**kwargs,
):
@forbid_nonstring_types(forbidden_types, name=name)
def wrapper1(self, pat):
result = f(self._parent, pat)
return self._wrap_result(result, returns_string=returns_string)
@forbid_nonstring_types(forbidden_types, name=name)
def wrapper2(self, pat, flags=0, **kwargs):
result = f(self._parent, pat, flags=flags, **kwargs)
return self._wrap_result(result, returns_string=returns_string)
@forbid_nonstring_types(forbidden_types, name=name)
def wrapper3(self, pat, na=np.nan):
result = f(self._parent, pat, na=na)
return self._wrap_result(result, returns_string=returns_string)
wrapper = wrapper3 if na else wrapper2 if flags else wrapper1
wrapper.__name__ = f.__name__ if name is None else name
if f.__doc__:
wrapper.__doc__ = f.__doc__
return wrapper
def copy(source):
"Copy a docstring from another source function (if present)"
def do_copy(target):
if source.__doc__:
target.__doc__ = source.__doc__
return target
return do_copy
class StringMethods(NoNewAttributesMixin):
"""
Vectorized string functions for Series and Index. NAs stay NA unless
handled otherwise by a particular method. Patterned after Python's string
methods, with some inspiration from R's stringr package.
Examples
--------
>>> s.str.split('_')
>>> s.str.replace('_', '')
"""
def __init__(self, data):
self._inferred_dtype = self._validate(data)
self._is_categorical = is_categorical_dtype(data)
self._is_string = data.dtype.name == "string"
# .values.categories works for both Series/Index
self._parent = data.values.categories if self._is_categorical else data
# save orig to blow up categoricals to the right type
self._orig = data
self._freeze()
@staticmethod
def _validate(data):
"""
Auxiliary function for StringMethods, infers and checks dtype of data.
This is a "first line of defence" at the creation of the StringMethods-
object (see _make_accessor), and just checks that the dtype is in the
*union* of the allowed types over all string methods below; this
restriction is then refined on a per-method basis using the decorator
@forbid_nonstring_types (more info in the corresponding docstring).
This really should exclude all series/index with any non-string values,
but that isn't practical for performance reasons until we have a str
dtype (GH 9343 / 13877)
Parameters
----------
data : The content of the Series
Returns
-------
dtype : inferred dtype of data
"""
from pandas import StringDtype
if isinstance(data, ABCMultiIndex):
raise AttributeError(
"Can only use .str accessor with Index, not MultiIndex"
)
# see _libs/lib.pyx for list of inferred types
allowed_types = ["string", "empty", "bytes", "mixed", "mixed-integer"]
values = getattr(data, "values", data) # Series / Index
values = getattr(values, "categories", values) # categorical / normal
# explicitly allow StringDtype
if isinstance(values.dtype, StringDtype):
return "string"
try:
inferred_dtype = lib.infer_dtype(values, skipna=True)
except ValueError:
# GH#27571 mostly occurs with ExtensionArray
inferred_dtype = None
if inferred_dtype not in allowed_types:
raise AttributeError("Can only use .str accessor with string values!")
return inferred_dtype
def __getitem__(self, key):
if isinstance(key, slice):
return self.slice(start=key.start, stop=key.stop, step=key.step)
else:
return self.get(key)
def __iter__(self):
i = 0
g = self.get(i)
while g.notna().any():
yield g
i += 1
g = self.get(i)
def _wrap_result(
self,
result,
use_codes=True,
name=None,
expand=None,
fill_value=np.nan,
returns_string=True,
):
from pandas import Index, Series, MultiIndex
# for category, we do the stuff on the categories, so blow it up
# to the full series again
# But for some operations, we have to do the stuff on the full values,
# so make it possible to skip this step as the method already did this
# before the transformation...
if use_codes and self._is_categorical:
# if self._orig is a CategoricalIndex, there is no .cat-accessor
result = take_1d(
result, Series(self._orig, copy=False).cat.codes, fill_value=fill_value
)
if not hasattr(result, "ndim") or not hasattr(result, "dtype"):
return result
assert result.ndim < 3
# We can be wrapping a string / object / categorical result, in which
# case we'll want to return the same dtype as the input.
# Or we can be wrapping a numeric output, in which case we don't want
# to return a StringArray.
if self._is_string and returns_string:
dtype = "string"
else:
dtype = None
if expand is None:
# infer from ndim if expand is not specified
expand = result.ndim != 1
elif expand is True and not isinstance(self._orig, ABCIndexClass):
# required when expand=True is explicitly specified
# not needed when inferred
def cons_row(x):
if is_list_like(x):
return x
else:
return [x]
result = [cons_row(x) for x in result]
if result:
# propagate nan values to match longest sequence (GH 18450)
max_len = max(len(x) for x in result)
result = [
x * max_len if len(x) == 0 or x[0] is np.nan else x for x in result
]
if not isinstance(expand, bool):
raise ValueError("expand must be True or False")
if expand is False:
# if expand is False, result should have the same name
# as the original otherwise specified
if name is None:
name = getattr(result, "name", None)
if name is None:
# do not use logical or, _orig may be a DataFrame
# which has "name" column
name = self._orig.name
# Wait until we are sure result is a Series or Index before
# checking attributes (GH 12180)
if isinstance(self._orig, ABCIndexClass):
# if result is a boolean np.array, return the np.array
# instead of wrapping it into a boolean Index (GH 8875)
if is_bool_dtype(result):
return result
if expand:
result = list(result)
out = MultiIndex.from_tuples(result, names=name)
if out.nlevels == 1:
# We had all tuples of length-one, which are
# better represented as a regular Index.
out = out.get_level_values(0)
return out
else:
return Index(result, name=name)
else:
index = self._orig.index
if expand:
cons = self._orig._constructor_expanddim
result = cons(result, columns=name, index=index, dtype=dtype)
else:
# Must be a Series
cons = self._orig._constructor
result = cons(result, name=name, index=index, dtype=dtype)
return result
def _get_series_list(self, others):
"""
Auxiliary function for :meth:`str.cat`. Turn potentially mixed input
into a list of Series (elements without an index must match the length
of the calling Series/Index).
Parameters
----------
others : Series, DataFrame, np.ndarray, list-like or list-like of
Objects that are either Series, Index or np.ndarray (1-dim).
Returns
-------
list of Series
Others transformed into list of Series.
"""
from pandas import Series, DataFrame
# self._orig is either Series or Index
idx = self._orig if isinstance(self._orig, ABCIndexClass) else self._orig.index
# Generally speaking, all objects without an index inherit the index
# `idx` of the calling Series/Index - i.e. must have matching length.
# Objects with an index (i.e. Series/Index/DataFrame) keep their own.
if isinstance(others, ABCSeries):
return [others]
elif isinstance(others, ABCIndexClass):
return [Series(others.values, index=others)]
elif isinstance(others, ABCDataFrame):
return [others[x] for x in others]
elif isinstance(others, np.ndarray) and others.ndim == 2:
others = DataFrame(others, index=idx)
return [others[x] for x in others]
elif is_list_like(others, allow_sets=False):
others = list(others) # ensure iterators do not get read twice etc
# in case of list-like `others`, all elements must be
# either Series/Index/np.ndarray (1-dim)...
if all(
isinstance(x, (ABCSeries, ABCIndexClass))
or (isinstance(x, np.ndarray) and x.ndim == 1)
for x in others
):
los = []
while others: # iterate through list and append each element
los = los + self._get_series_list(others.pop(0))
return los
# ... or just strings
elif all(not is_list_like(x) for x in others):
return [Series(others, index=idx)]
raise TypeError(
"others must be Series, Index, DataFrame, np.ndarrary "
"or list-like (either containing only strings or "
"containing only objects of type Series/Index/"
"np.ndarray[1-dim])"
)
@forbid_nonstring_types(["bytes", "mixed", "mixed-integer"])
def cat(self, others=None, sep=None, na_rep=None, join="left"):
"""
Concatenate strings in the Series/Index with given separator.
If `others` is specified, this function concatenates the Series/Index
and elements of `others` element-wise.
If `others` is not passed, then all values in the Series/Index are
concatenated into a single string with a given `sep`.
Parameters
----------
others : Series, Index, DataFrame, np.ndarray or list-like
Series, Index, DataFrame, np.ndarray (one- or two-dimensional) and
other list-likes of strings must have the same length as the
calling Series/Index, with the exception of indexed objects (i.e.
Series/Index/DataFrame) if `join` is not None.
If others is a list-like that contains a combination of Series,
Index or np.ndarray (1-dim), then all elements will be unpacked and
must satisfy the above criteria individually.
If others is None, the method returns the concatenation of all
strings in the calling Series/Index.
sep : str, default ''
The separator between the different elements/columns. By default
the empty string `''` is used.
na_rep : str or None, default None
Representation that is inserted for all missing values:
- If `na_rep` is None, and `others` is None, missing values in the
Series/Index are omitted from the result.
- If `na_rep` is None, and `others` is not None, a row containing a
missing value in any of the columns (before concatenation) will
have a missing value in the result.
join : {'left', 'right', 'outer', 'inner'}, default 'left'
Determines the join-style between the calling Series/Index and any
Series/Index/DataFrame in `others` (objects without an index need
to match the length of the calling Series/Index). To disable
alignment, use `.values` on any Series/Index/DataFrame in `others`.
.. versionadded:: 0.23.0
.. versionchanged:: 1.0.0
Changed default of `join` from None to `'left'`.
Returns
-------
str, Series or Index
If `others` is None, `str` is returned, otherwise a `Series/Index`
(same type as caller) of objects is returned.
See Also
--------
split : Split each string in the Series/Index.
join : Join lists contained as elements in the Series/Index.
Examples
--------
When not passing `others`, all values are concatenated into a single
string:
>>> s = pd.Series(['a', 'b', np.nan, 'd'])
>>> s.str.cat(sep=' ')
'a b d'
By default, NA values in the Series are ignored. Using `na_rep`, they
can be given a representation:
>>> s.str.cat(sep=' ', na_rep='?')
'a b ? d'
If `others` is specified, corresponding values are concatenated with
the separator. Result will be a Series of strings.
>>> s.str.cat(['A', 'B', 'C', 'D'], sep=',')
0 a,A
1 b,B
2 NaN
3 d,D
dtype: object
Missing values will remain missing in the result, but can again be
represented using `na_rep`
>>> s.str.cat(['A', 'B', 'C', 'D'], sep=',', na_rep='-')
0 a,A
1 b,B
2 -,C
3 d,D
dtype: object
If `sep` is not specified, the values are concatenated without
separation.
>>> s.str.cat(['A', 'B', 'C', 'D'], na_rep='-')
0 aA
1 bB
2 -C
3 dD
dtype: object
Series with different indexes can be aligned before concatenation. The
`join`-keyword works as in other methods.
>>> t = pd.Series(['d', 'a', 'e', 'c'], index=[3, 0, 4, 2])
>>> s.str.cat(t, join='left', na_rep='-')
0 aa
1 b-
2 -c
3 dd
dtype: object
>>>
>>> s.str.cat(t, join='outer', na_rep='-')
0 aa
1 b-
2 -c
3 dd
4 -e
dtype: object
>>>
>>> s.str.cat(t, join='inner', na_rep='-')
0 aa
2 -c
3 dd
dtype: object
>>>
>>> s.str.cat(t, join='right', na_rep='-')
3 dd
0 aa
4 -e
2 -c
dtype: object
For more examples, see :ref:`here <text.concatenate>`.
"""
from pandas import Index, Series, concat
if isinstance(others, str):
raise ValueError("Did you mean to supply a `sep` keyword?")
if sep is None:
sep = ""
if isinstance(self._orig, ABCIndexClass):
data = Series(self._orig, index=self._orig)
else: # Series
data = self._orig
# concatenate Series/Index with itself if no "others"
if others is None:
data = ensure_object(data)
na_mask = isna(data)
if na_rep is None and na_mask.any():
data = data[~na_mask]
elif na_rep is not None and na_mask.any():
data = np.where(na_mask, na_rep, data)
return sep.join(data)
try:
# turn anything in "others" into lists of Series
others = self._get_series_list(others)
except ValueError: # do not catch TypeError raised by _get_series_list
raise ValueError(
"If `others` contains arrays or lists (or other "
"list-likes without an index), these must all be "
"of the same length as the calling Series/Index."
)
# align if required
if any(not data.index.equals(x.index) for x in others):
# Need to add keys for uniqueness in case of duplicate columns
others = concat(
others,
axis=1,
join=(join if join == "inner" else "outer"),
keys=range(len(others)),
sort=False,
copy=False,
)
data, others = data.align(others, join=join)
others = [others[x] for x in others] # again list of Series
all_cols = [ensure_object(x) for x in [data] + others]
na_masks = np.array([isna(x) for x in all_cols])
union_mask = np.logical_or.reduce(na_masks, axis=0)
if na_rep is None and union_mask.any():
# no na_rep means NaNs for all rows where any column has a NaN
# only necessary if there are actually any NaNs
result = np.empty(len(data), dtype=object)
np.putmask(result, union_mask, np.nan)
not_masked = ~union_mask
result[not_masked] = cat_safe([x[not_masked] for x in all_cols], sep)
elif na_rep is not None and union_mask.any():
# fill NaNs with na_rep in case there are actually any NaNs
all_cols = [
np.where(nm, na_rep, col) for nm, col in zip(na_masks, all_cols)
]
result = cat_safe(all_cols, sep)
else:
# no NaNs - can just concatenate
result = cat_safe(all_cols, sep)
if isinstance(self._orig, ABCIndexClass):
# add dtype for case that result is all-NA
result = Index(result, dtype=object, name=self._orig.name)
else: # Series
if is_categorical_dtype(self._orig.dtype):
# We need to infer the new categories.
dtype = None
else:
dtype = self._orig.dtype
result = Series(result, dtype=dtype, index=data.index, name=self._orig.name)
return result
_shared_docs[
"str_split"
] = r"""
Split strings around given separator/delimiter.
Splits the string in the Series/Index from the %(side)s,
at the specified delimiter string. Equivalent to :meth:`str.%(method)s`.
Parameters
----------
pat : str, optional
String or regular expression to split on.
If not specified, split on whitespace.
n : int, default -1 (all)
Limit number of splits in output.
``None``, 0 and -1 will be interpreted as return all splits.
expand : bool, default False
Expand the splitted strings into separate columns.
* If ``True``, return DataFrame/MultiIndex expanding dimensionality.
* If ``False``, return Series/Index, containing lists of strings.
Returns
-------
Series, Index, DataFrame or MultiIndex
Type matches caller unless ``expand=True`` (see Notes).
See Also
--------
Series.str.split : Split strings around given separator/delimiter.
Series.str.rsplit : Splits string around given separator/delimiter,
starting from the right.
Series.str.join : Join lists contained as elements in the Series/Index
with passed delimiter.
str.split : Standard library version for split.
str.rsplit : Standard library version for rsplit.
Notes
-----
The handling of the `n` keyword depends on the number of found splits:
- If found splits > `n`, make first `n` splits only
- If found splits <= `n`, make all splits
- If for a certain row the number of found splits < `n`,
append `None` for padding up to `n` if ``expand=True``
If using ``expand=True``, Series and Index callers return DataFrame and
MultiIndex objects, respectively.
Examples
--------
>>> s = pd.Series(["this is a regular sentence",
... "https://docs.python.org/3/tutorial/index.html",
... np.nan])
0 this is a regular sentence
1 https://docs.python.org/3/tutorial/index.html
2 NaN
dtype: object
In the default setting, the string is split by whitespace.
>>> s.str.split()
0 [this, is, a, regular, sentence]
1 [https://docs.python.org/3/tutorial/index.html]
2 NaN
dtype: object
Without the `n` parameter, the outputs of `rsplit` and `split`
are identical.
>>> s.str.rsplit()
0 [this, is, a, regular, sentence]
1 [https://docs.python.org/3/tutorial/index.html]
2 NaN
dtype: object
The `n` parameter can be used to limit the number of splits on the
delimiter. The outputs of `split` and `rsplit` are different.
>>> s.str.split(n=2)
0 [this, is, a regular sentence]
1 [https://docs.python.org/3/tutorial/index.html]
2 NaN
dtype: object
>>> s.str.rsplit(n=2)
0 [this is a, regular, sentence]
1 [https://docs.python.org/3/tutorial/index.html]
2 NaN
dtype: object
The `pat` parameter can be used to split by other characters.
>>> s.str.split(pat = "/")
0 [this is a regular sentence]
1 [https:, , docs.python.org, 3, tutorial, index...
2 NaN
dtype: object
When using ``expand=True``, the split elements will expand out into
separate columns. If NaN is present, it is propagated throughout
the columns during the split.
>>> s.str.split(expand=True)
0 1 2 3
0 this is a regular
1 https://docs.python.org/3/tutorial/index.html None None None
2 NaN NaN NaN NaN \
4
0 sentence
1 None
2 NaN
For slightly more complex use cases like splitting the html document name
from a url, a combination of parameter settings can be used.
>>> s.str.rsplit("/", n=1, expand=True)
0 1
0 this is a regular sentence None
1 https://docs.python.org/3/tutorial index.html
2 NaN NaN
Remember to escape special characters when explicitly using regular
expressions.
>>> s = pd.Series(["1+1=2"])
>>> s.str.split(r"\+|=", expand=True)
0 1 2
0 1 1 2
"""
@Appender(_shared_docs["str_split"] % {"side": "beginning", "method": "split"})
@forbid_nonstring_types(["bytes"])
def split(self, pat=None, n=-1, expand=False):
result = str_split(self._parent, pat, n=n)
return self._wrap_result(result, expand=expand, returns_string=expand)
@Appender(_shared_docs["str_split"] % {"side": "end", "method": "rsplit"})
@forbid_nonstring_types(["bytes"])
def rsplit(self, pat=None, n=-1, expand=False):
result = str_rsplit(self._parent, pat, n=n)
return self._wrap_result(result, expand=expand, returns_string=expand)
_shared_docs[
"str_partition"
] = """
Split the string at the %(side)s occurrence of `sep`.
This method splits the string at the %(side)s occurrence of `sep`,
and returns 3 elements containing the part before the separator,
the separator itself, and the part after the separator.
If the separator is not found, return %(return)s.
Parameters
----------
sep : str, default whitespace
String to split on.
pat : str, default whitespace
.. deprecated:: 0.24.0
Use ``sep`` instead.
expand : bool, default True
If True, return DataFrame/MultiIndex expanding dimensionality.
If False, return Series/Index.
Returns
-------
DataFrame/MultiIndex or Series/Index of objects
See Also
--------
%(also)s
Series.str.split : Split strings around given separators.
str.partition : Standard library version.
Examples
--------
>>> s = pd.Series(['Linda van der Berg', 'George Pitt-Rivers'])
>>> s
0 Linda van der Berg
1 George Pitt-Rivers
dtype: object
>>> s.str.partition()
0 1 2
0 Linda van der Berg
1 George Pitt-Rivers
To partition by the last space instead of the first one:
>>> s.str.rpartition()
0 1 2
0 Linda van der Berg
1 George Pitt-Rivers
To partition by something different than a space:
>>> s.str.partition('-')
0 1 2
0 Linda van der Berg
1 George Pitt - Rivers
To return a Series containing tuples instead of a DataFrame:
>>> s.str.partition('-', expand=False)
0 (Linda van der Berg, , )
1 (George Pitt, -, Rivers)
dtype: object
Also available on indices:
>>> idx = pd.Index(['X 123', 'Y 999'])
>>> idx
Index(['X 123', 'Y 999'], dtype='object')
Which will create a MultiIndex:
>>> idx.str.partition()
MultiIndex([('X', ' ', '123'),
('Y', ' ', '999')],
dtype='object')
Or an index with tuples with ``expand=False``:
>>> idx.str.partition(expand=False)
Index([('X', ' ', '123'), ('Y', ' ', '999')], dtype='object')
"""
@Appender(
_shared_docs["str_partition"]
% {
"side": "first",
"return": "3 elements containing the string itself, followed by two "
"empty strings",
"also": "rpartition : Split the string at the last occurrence of `sep`.",
}
)
@deprecate_kwarg(old_arg_name="pat", new_arg_name="sep")
@forbid_nonstring_types(["bytes"])
def partition(self, sep=" ", expand=True):
f = lambda x: x.partition(sep)
result = _na_map(f, self._parent)
return self._wrap_result(result, expand=expand, returns_string=expand)
@Appender(
_shared_docs["str_partition"]
% {
"side": "last",
"return": "3 elements containing two empty strings, followed by the "
"string itself",
"also": "partition : Split the string at the first occurrence of `sep`.",
}
)
@deprecate_kwarg(old_arg_name="pat", new_arg_name="sep")
@forbid_nonstring_types(["bytes"])
def rpartition(self, sep=" ", expand=True):
f = lambda x: x.rpartition(sep)
result = _na_map(f, self._parent)
return self._wrap_result(result, expand=expand, returns_string=expand)
@copy(str_get)
def get(self, i):
result = str_get(self._parent, i)
return self._wrap_result(result)
@copy(str_join)
@forbid_nonstring_types(["bytes"])
def join(self, sep):
result = str_join(self._parent, sep)
return self._wrap_result(result)
@copy(str_contains)
@forbid_nonstring_types(["bytes"])
def contains(self, pat, case=True, flags=0, na=np.nan, regex=True):
result = str_contains(
self._parent, pat, case=case, flags=flags, na=na, regex=regex
)
return self._wrap_result(result, fill_value=na, returns_string=False)
@copy(str_match)
@forbid_nonstring_types(["bytes"])
def match(self, pat, case=True, flags=0, na=np.nan):
result = str_match(self._parent, pat, case=case, flags=flags, na=na)
return self._wrap_result(result, fill_value=na, returns_string=False)
@copy(str_replace)
@forbid_nonstring_types(["bytes"])
def replace(self, pat, repl, n=-1, case=None, flags=0, regex=True):
result = str_replace(
self._parent, pat, repl, n=n, case=case, flags=flags, regex=regex
)
return self._wrap_result(result)
@copy(str_repeat)
@forbid_nonstring_types(["bytes"])
def repeat(self, repeats):
result = str_repeat(self._parent, repeats)
return self._wrap_result(result)
@copy(str_pad)
@forbid_nonstring_types(["bytes"])
def pad(self, width, side="left", fillchar=" "):
result = str_pad(self._parent, width, side=side, fillchar=fillchar)
return self._wrap_result(result)
_shared_docs[
"str_pad"
] = """
Filling %(side)s side of strings in the Series/Index with an
additional character. Equivalent to :meth:`str.%(method)s`.
Parameters
----------
width : int
Minimum width of resulting string; additional characters will be filled
with ``fillchar``.
fillchar : str
Additional character for filling, default is whitespace.
Returns
-------
filled : Series/Index of objects.
"""
@Appender(_shared_docs["str_pad"] % dict(side="left and right", method="center"))
@forbid_nonstring_types(["bytes"])
def center(self, width, fillchar=" "):
return self.pad(width, side="both", fillchar=fillchar)
@Appender(_shared_docs["str_pad"] % dict(side="right", method="ljust"))
@forbid_nonstring_types(["bytes"])
def ljust(self, width, fillchar=" "):
return self.pad(width, side="right", fillchar=fillchar)
@Appender(_shared_docs["str_pad"] % dict(side="left", method="rjust"))
@forbid_nonstring_types(["bytes"])
def rjust(self, width, fillchar=" "):
return self.pad(width, side="left", fillchar=fillchar)
@forbid_nonstring_types(["bytes"])
def zfill(self, width):
"""
Pad strings in the Series/Index by prepending '0' characters.
Strings in the Series/Index are padded with '0' characters on the
left of the string to reach a total string length `width`. Strings
in the Series/Index with length greater or equal to `width` are
unchanged.
Parameters
----------
width : int
Minimum length of resulting string; strings with length less
than `width` be prepended with '0' characters.
Returns
-------
Series/Index of objects.
See Also
--------
Series.str.rjust : Fills the left side of strings with an arbitrary
character.
Series.str.ljust : Fills the right side of strings with an arbitrary
character.
Series.str.pad : Fills the specified sides of strings with an arbitrary
character.
Series.str.center : Fills boths sides of strings with an arbitrary
character.
Notes
-----
Differs from :meth:`str.zfill` which has special handling
for '+'/'-' in the string.
Examples
--------
>>> s = pd.Series(['-1', '1', '1000', 10, np.nan])
>>> s
0 -1
1 1
2 1000
3 10
4 NaN
dtype: object
Note that ``10`` and ``NaN`` are not strings, therefore they are
converted to ``NaN``. The minus sign in ``'-1'`` is treated as a
regular character and the zero is added to the left of it
(:meth:`str.zfill` would have moved it to the left). ``1000``
remains unchanged as it is longer than `width`.
>>> s.str.zfill(3)
0 0-1
1 001
2 1000
3 NaN
4 NaN
dtype: object
"""
result = str_pad(self._parent, width, side="left", fillchar="0")
return self._wrap_result(result)
@copy(str_slice)
def slice(self, start=None, stop=None, step=None):
result = str_slice(self._parent, start, stop, step)
return self._wrap_result(result)
@copy(str_slice_replace)
@forbid_nonstring_types(["bytes"])
def slice_replace(self, start=None, stop=None, repl=None):
result = str_slice_replace(self._parent, start, stop, repl)
return self._wrap_result(result)
@copy(str_decode)
def decode(self, encoding, errors="strict"):
# need to allow bytes here
result = str_decode(self._parent, encoding, errors)
# TODO: Not sure how to handle this.
return self._wrap_result(result, returns_string=False)
@copy(str_encode)
@forbid_nonstring_types(["bytes"])
def encode(self, encoding, errors="strict"):
result = str_encode(self._parent, encoding, errors)
return self._wrap_result(result, returns_string=False)
_shared_docs[
"str_strip"
] = r"""
Remove leading and trailing characters.
Strip whitespaces (including newlines) or a set of specified characters
from each string in the Series/Index from %(side)s.
Equivalent to :meth:`str.%(method)s`.
Parameters
----------
to_strip : str or None, default None
Specifying the set of characters to be removed.
All combinations of this set of characters will be stripped.
If None then whitespaces are removed.
Returns
-------
Series or Index of object
See Also
--------
Series.str.strip : Remove leading and trailing characters in Series/Index.
Series.str.lstrip : Remove leading characters in Series/Index.
Series.str.rstrip : Remove trailing characters in Series/Index.
Examples
--------
>>> s = pd.Series(['1. Ant. ', '2. Bee!\n', '3. Cat?\t', np.nan])
>>> s
0 1. Ant.
1 2. Bee!\n
2 3. Cat?\t
3 NaN
dtype: object
>>> s.str.strip()
0 1. Ant.
1 2. Bee!
2 3. Cat?
3 NaN
dtype: object
>>> s.str.lstrip('123.')
0 Ant.
1 Bee!\n
2 Cat?\t
3 NaN
dtype: object
>>> s.str.rstrip('.!? \n\t')
0 1. Ant
1 2. Bee
2 3. Cat
3 NaN
dtype: object
>>> s.str.strip('123.!? \n\t')
0 Ant
1 Bee
2 Cat
3 NaN
dtype: object
"""
@Appender(
_shared_docs["str_strip"] % dict(side="left and right sides", method="strip")
)
@forbid_nonstring_types(["bytes"])
def strip(self, to_strip=None):
result = str_strip(self._parent, to_strip, side="both")
return self._wrap_result(result)
@Appender(_shared_docs["str_strip"] % dict(side="left side", method="lstrip"))
@forbid_nonstring_types(["bytes"])
def lstrip(self, to_strip=None):
result = str_strip(self._parent, to_strip, side="left")
return self._wrap_result(result)
@Appender(_shared_docs["str_strip"] % dict(side="right side", method="rstrip"))
@forbid_nonstring_types(["bytes"])
def rstrip(self, to_strip=None):
result = str_strip(self._parent, to_strip, side="right")
return self._wrap_result(result)
@copy(str_wrap)
@forbid_nonstring_types(["bytes"])
def wrap(self, width, **kwargs):
result = str_wrap(self._parent, width, **kwargs)
return self._wrap_result(result)
@copy(str_get_dummies)
@forbid_nonstring_types(["bytes"])
def get_dummies(self, sep="|"):
# we need to cast to Series of strings as only that has all
# methods available for making the dummies...
data = self._orig.astype(str) if self._is_categorical else self._parent
result, name = str_get_dummies(data, sep)
return self._wrap_result(
result,
use_codes=(not self._is_categorical),
name=name,
expand=True,
returns_string=False,
)
@copy(str_translate)
@forbid_nonstring_types(["bytes"])
def translate(self, table):
result = str_translate(self._parent, table)
return self._wrap_result(result)
count = _pat_wrapper(str_count, flags=True, name="count", returns_string=False)
startswith = _pat_wrapper(
str_startswith, na=True, name="startswith", returns_string=False
)
endswith = _pat_wrapper(
str_endswith, na=True, name="endswith", returns_string=False
)
findall = _pat_wrapper(
str_findall, flags=True, name="findall", returns_string=False
)
@copy(str_extract)
@forbid_nonstring_types(["bytes"])
def extract(self, pat, flags=0, expand=True):
return str_extract(self, pat, flags=flags, expand=expand)
@copy(str_extractall)
@forbid_nonstring_types(["bytes"])
def extractall(self, pat, flags=0):
return str_extractall(self._orig, pat, flags=flags)
_shared_docs[
"find"
] = """
Return %(side)s indexes in each strings in the Series/Index
where the substring is fully contained between [start:end].
Return -1 on failure. Equivalent to standard :meth:`str.%(method)s`.
Parameters
----------
sub : str
Substring being searched.
start : int
Left edge index.
end : int
Right edge index.
Returns
-------
Series or Index of int.
See Also
--------
%(also)s
"""
@Appender(
_shared_docs["find"]
% dict(
side="lowest",
method="find",
also="rfind : Return highest indexes in each strings.",
)
)
@forbid_nonstring_types(["bytes"])
def find(self, sub, start=0, end=None):
result = str_find(self._parent, sub, start=start, end=end, side="left")
return self._wrap_result(result, returns_string=False)
@Appender(
_shared_docs["find"]
% dict(
side="highest",
method="rfind",
also="find : Return lowest indexes in each strings.",
)
)
@forbid_nonstring_types(["bytes"])
def rfind(self, sub, start=0, end=None):
result = str_find(self._parent, sub, start=start, end=end, side="right")
return self._wrap_result(result, returns_string=False)
@forbid_nonstring_types(["bytes"])
def normalize(self, form):
"""
Return the Unicode normal form for the strings in the Series/Index.
For more information on the forms, see the
:func:`unicodedata.normalize`.
Parameters
----------
form : {'NFC', 'NFKC', 'NFD', 'NFKD'}
Unicode form.
Returns
-------
normalized : Series/Index of objects
"""
import unicodedata
f = lambda x: unicodedata.normalize(form, x)
result = _na_map(f, self._parent)
return self._wrap_result(result)
_shared_docs[
"index"
] = """
Return %(side)s indexes in each strings where the substring is
fully contained between [start:end]. This is the same as
``str.%(similar)s`` except instead of returning -1, it raises a ValueError
when the substring is not found. Equivalent to standard ``str.%(method)s``.
Parameters
----------
sub : str
Substring being searched.
start : int
Left edge index.
end : int
Right edge index.
Returns
-------
Series or Index of object
See Also
--------
%(also)s
"""
@Appender(
_shared_docs["index"]
% dict(
side="lowest",
similar="find",
method="index",
also="rindex : Return highest indexes in each strings.",
)
)
@forbid_nonstring_types(["bytes"])
def index(self, sub, start=0, end=None):
result = str_index(self._parent, sub, start=start, end=end, side="left")
return self._wrap_result(result, returns_string=False)
@Appender(
_shared_docs["index"]
% dict(
side="highest",
similar="rfind",
method="rindex",
also="index : Return lowest indexes in each strings.",
)
)
@forbid_nonstring_types(["bytes"])
def rindex(self, sub, start=0, end=None):
result = str_index(self._parent, sub, start=start, end=end, side="right")
return self._wrap_result(result, returns_string=False)
_shared_docs[
"len"
] = """
Compute the length of each element in the Series/Index. The element may be
a sequence (such as a string, tuple or list) or a collection
(such as a dictionary).
Returns
-------
Series or Index of int
A Series or Index of integer values indicating the length of each
element in the Series or Index.
See Also
--------
str.len : Python built-in function returning the length of an object.
Series.size : Returns the length of the Series.
Examples
--------
Returns the length (number of characters) in a string. Returns the
number of entries for dictionaries, lists or tuples.
>>> s = pd.Series(['dog',
... '',
... 5,
... {'foo' : 'bar'},
... [2, 3, 5, 7],
... ('one', 'two', 'three')])
>>> s
0 dog
1
2 5
3 {'foo': 'bar'}
4 [2, 3, 5, 7]
5 (one, two, three)
dtype: object
>>> s.str.len()
0 3.0
1 0.0
2 NaN
3 1.0
4 4.0
5 3.0
dtype: float64
"""
len = _noarg_wrapper(
len,
docstring=_shared_docs["len"],
forbidden_types=None,
dtype=int,
returns_string=False,
)
_shared_docs[
"casemethods"
] = """
Convert strings in the Series/Index to %(type)s.
%(version)s
Equivalent to :meth:`str.%(method)s`.
Returns
-------
Series or Index of object
See Also
--------
Series.str.lower : Converts all characters to lowercase.
Series.str.upper : Converts all characters to uppercase.
Series.str.title : Converts first character of each word to uppercase and
remaining to lowercase.
Series.str.capitalize : Converts first character to uppercase and
remaining to lowercase.
Series.str.swapcase : Converts uppercase to lowercase and lowercase to
uppercase.
Series.str.casefold: Removes all case distinctions in the string.
Examples
--------
>>> s = pd.Series(['lower', 'CAPITALS', 'this is a sentence', 'SwApCaSe'])
>>> s
0 lower
1 CAPITALS
2 this is a sentence
3 SwApCaSe
dtype: object
>>> s.str.lower()
0 lower
1 capitals
2 this is a sentence
3 swapcase
dtype: object
>>> s.str.upper()
0 LOWER
1 CAPITALS
2 THIS IS A SENTENCE
3 SWAPCASE
dtype: object
>>> s.str.title()
0 Lower
1 Capitals
2 This Is A Sentence
3 Swapcase
dtype: object
>>> s.str.capitalize()
0 Lower
1 Capitals
2 This is a sentence
3 Swapcase
dtype: object
>>> s.str.swapcase()
0 LOWER
1 capitals
2 THIS IS A SENTENCE
3 sWaPcAsE
dtype: object
"""
# _doc_args holds dict of strings to use in substituting casemethod docs
_doc_args = {} # type: Dict[str, Dict[str, str]]
_doc_args["lower"] = dict(type="lowercase", method="lower", version="")
_doc_args["upper"] = dict(type="uppercase", method="upper", version="")
_doc_args["title"] = dict(type="titlecase", method="title", version="")
_doc_args["capitalize"] = dict(
type="be capitalized", method="capitalize", version=""
)
_doc_args["swapcase"] = dict(type="be swapcased", method="swapcase", version="")
_doc_args["casefold"] = dict(
type="be casefolded",
method="casefold",
version="\n .. versionadded:: 0.25.0\n",
)
lower = _noarg_wrapper(
lambda x: x.lower(),
name="lower",
docstring=_shared_docs["casemethods"] % _doc_args["lower"],
)
upper = _noarg_wrapper(
lambda x: x.upper(),
name="upper",
docstring=_shared_docs["casemethods"] % _doc_args["upper"],
)
title = _noarg_wrapper(
lambda x: x.title(),
name="title",
docstring=_shared_docs["casemethods"] % _doc_args["title"],
)
capitalize = _noarg_wrapper(
lambda x: x.capitalize(),
name="capitalize",
docstring=_shared_docs["casemethods"] % _doc_args["capitalize"],
)
swapcase = _noarg_wrapper(
lambda x: x.swapcase(),
name="swapcase",
docstring=_shared_docs["casemethods"] % _doc_args["swapcase"],
)
casefold = _noarg_wrapper(
lambda x: x.casefold(),
name="casefold",
docstring=_shared_docs["casemethods"] % _doc_args["casefold"],
)
_shared_docs[
"ismethods"
] = """
Check whether all characters in each string are %(type)s.
This is equivalent to running the Python string method
:meth:`str.%(method)s` for each element of the Series/Index. If a string
has zero characters, ``False`` is returned for that check.
Returns
-------
Series or Index of bool
Series or Index of boolean values with the same length as the original
Series/Index.
See Also
--------
Series.str.isalpha : Check whether all characters are alphabetic.
Series.str.isnumeric : Check whether all characters are numeric.
Series.str.isalnum : Check whether all characters are alphanumeric.
Series.str.isdigit : Check whether all characters are digits.
Series.str.isdecimal : Check whether all characters are decimal.
Series.str.isspace : Check whether all characters are whitespace.
Series.str.islower : Check whether all characters are lowercase.
Series.str.isupper : Check whether all characters are uppercase.
Series.str.istitle : Check whether all characters are titlecase.
Examples
--------
**Checks for Alphabetic and Numeric Characters**
>>> s1 = pd.Series(['one', 'one1', '1', ''])
>>> s1.str.isalpha()
0 True
1 False
2 False
3 False
dtype: bool
>>> s1.str.isnumeric()
0 False
1 False
2 True
3 False
dtype: bool
>>> s1.str.isalnum()
0 True
1 True
2 True
3 False
dtype: bool
Note that checks against characters mixed with any additional punctuation
or whitespace will evaluate to false for an alphanumeric check.
>>> s2 = pd.Series(['A B', '1.5', '3,000'])
>>> s2.str.isalnum()
0 False
1 False
2 False
dtype: bool
**More Detailed Checks for Numeric Characters**
There are several different but overlapping sets of numeric characters that
can be checked for.
>>> s3 = pd.Series(['23', '³', '⅕', ''])
The ``s3.str.isdecimal`` method checks for characters used to form numbers
in base 10.
>>> s3.str.isdecimal()
0 True
1 False
2 False
3 False
dtype: bool
The ``s.str.isdigit`` method is the same as ``s3.str.isdecimal`` but also
includes special digits, like superscripted and subscripted digits in
unicode.
>>> s3.str.isdigit()
0 True
1 True
2 False
3 False
dtype: bool
The ``s.str.isnumeric`` method is the same as ``s3.str.isdigit`` but also
includes other characters that can represent quantities such as unicode
fractions.
>>> s3.str.isnumeric()
0 True
1 True
2 True
3 False
dtype: bool
**Checks for Whitespace**
>>> s4 = pd.Series([' ', '\\t\\r\\n ', ''])
>>> s4.str.isspace()
0 True
1 True
2 False
dtype: bool
**Checks for Character Case**
>>> s5 = pd.Series(['leopard', 'Golden Eagle', 'SNAKE', ''])
>>> s5.str.islower()
0 True
1 False
2 False
3 False
dtype: bool
>>> s5.str.isupper()
0 False
1 False
2 True
3 False
dtype: bool
The ``s5.str.istitle`` method checks for whether all words are in title
case (whether only the first letter of each word is capitalized). Words are
assumed to be as any sequence of non-numeric characters separated by
whitespace characters.
>>> s5.str.istitle()
0 False
1 True
2 False
3 False
dtype: bool
"""
_doc_args["isalnum"] = dict(type="alphanumeric", method="isalnum")
_doc_args["isalpha"] = dict(type="alphabetic", method="isalpha")
_doc_args["isdigit"] = dict(type="digits", method="isdigit")
_doc_args["isspace"] = dict(type="whitespace", method="isspace")
_doc_args["islower"] = dict(type="lowercase", method="islower")
_doc_args["isupper"] = dict(type="uppercase", method="isupper")
_doc_args["istitle"] = dict(type="titlecase", method="istitle")
_doc_args["isnumeric"] = dict(type="numeric", method="isnumeric")
_doc_args["isdecimal"] = dict(type="decimal", method="isdecimal")
isalnum = _noarg_wrapper(
lambda x: x.isalnum(),
name="isalnum",
docstring=_shared_docs["ismethods"] % _doc_args["isalnum"],
returns_string=False,
)
isalpha = _noarg_wrapper(
lambda x: x.isalpha(),
name="isalpha",
docstring=_shared_docs["ismethods"] % _doc_args["isalpha"],
returns_string=False,
)
isdigit = _noarg_wrapper(
lambda x: x.isdigit(),
name="isdigit",
docstring=_shared_docs["ismethods"] % _doc_args["isdigit"],
returns_string=False,
)
isspace = _noarg_wrapper(
lambda x: x.isspace(),
name="isspace",
docstring=_shared_docs["ismethods"] % _doc_args["isspace"],
returns_string=False,
)
islower = _noarg_wrapper(
lambda x: x.islower(),
name="islower",
docstring=_shared_docs["ismethods"] % _doc_args["islower"],
returns_string=False,
)
isupper = _noarg_wrapper(
lambda x: x.isupper(),
name="isupper",
docstring=_shared_docs["ismethods"] % _doc_args["isupper"],
returns_string=False,
)
istitle = _noarg_wrapper(
lambda x: x.istitle(),
name="istitle",
docstring=_shared_docs["ismethods"] % _doc_args["istitle"],
returns_string=False,
)
isnumeric = _noarg_wrapper(
lambda x: x.isnumeric(),
name="isnumeric",
docstring=_shared_docs["ismethods"] % _doc_args["isnumeric"],
returns_string=False,
)
isdecimal = _noarg_wrapper(
lambda x: x.isdecimal(),
name="isdecimal",
docstring=_shared_docs["ismethods"] % _doc_args["isdecimal"],
returns_string=False,
)
@classmethod
def _make_accessor(cls, data):
cls._validate(data)
return cls(data)
import codecs
from functools import wraps
import re
import textwrap
from typing import Dict, List
import warnings
import numpy as np
import pandas._libs.lib as lib
import pandas._libs.ops as libops
from pandas.util._decorators import Appender, deprecate_kwarg
from pandas.core.dtypes.common import (
ensure_object,
is_bool_dtype,
is_categorical_dtype,
is_integer,
is_list_like,
is_re,
is_scalar,
)
from pandas.core.dtypes.generic import (
ABCDataFrame,
ABCIndexClass,
ABCMultiIndex,
ABCSeries,
)
from pandas.core.dtypes.missing import isna
from pandas.core.algorithms import take_1d
from pandas.core.base import NoNewAttributesMixin
import pandas.core.common as com
_cpython_optimized_encoders = (
"utf-8",
"utf8",
"latin-1",
"latin1",
"iso-8859-1",
"mbcs",
"ascii",
)
_cpython_optimized_decoders = _cpython_optimized_encoders + ("utf-16", "utf-32")
_shared_docs = dict() # type: Dict[str, str]
def cat_core(list_of_columns: List, sep: str):
"""
Auxiliary function for :meth:`str.cat`
Parameters
----------
list_of_columns : list of numpy arrays
List of arrays to be concatenated with sep;
these arrays may not contain NaNs!
sep : string
The separator string for concatenating the columns.
Returns
-------
nd.array
The concatenation of list_of_columns with sep.
"""
if sep == "":
# no need to interleave sep if it is empty
return np.sum(list_of_columns, axis=0)
list_with_sep = [sep] * (2 * len(list_of_columns) - 1)
list_with_sep[::2] = list_of_columns
return np.sum(list_with_sep, axis=0)
def cat_safe(list_of_columns: List, sep: str):
"""
Auxiliary function for :meth:`str.cat`.
Same signature as cat_core, but handles TypeErrors in concatenation, which
happen if the arrays in list_of columns have the wrong dtypes or content.
Parameters
----------
list_of_columns : list of numpy arrays
List of arrays to be concatenated with sep;
these arrays may not contain NaNs!
sep : string
The separator string for concatenating the columns.
Returns
-------
nd.array
The concatenation of list_of_columns with sep.
"""
try:
result = cat_core(list_of_columns, sep)
except TypeError:
# if there are any non-string values (wrong dtype or hidden behind
# object dtype), np.sum will fail; catch and return with better message
for column in list_of_columns:
dtype = lib.infer_dtype(column, skipna=True)
if dtype not in ["string", "empty"]:
raise TypeError(
"Concatenation requires list-likes containing only "
"strings (or missing values). Offending values found in "
"column {}".format(dtype)
) from None
return result
def _na_map(f, arr, na_result=np.nan, dtype=object):
# should really _check_ for NA
return _map(f, arr, na_mask=True, na_value=na_result, dtype=dtype)
def _map(f, arr, na_mask=False, na_value=np.nan, dtype=object):
if not len(arr):
return np.ndarray(0, dtype=dtype)
if isinstance(arr, ABCSeries):
arr = arr.values
if not isinstance(arr, np.ndarray):
arr = np.asarray(arr, dtype=object)
if na_mask:
mask = isna(arr)
convert = not np.all(mask)
try:
result = lib.map_infer_mask(arr, f, mask.view(np.uint8), convert)
except (TypeError, AttributeError) as e:
# Reraise the exception if callable `f` got wrong number of args.
# The user may want to be warned by this, instead of getting NaN
p_err = (
r"((takes)|(missing)) (?(2)from \d+ to )?\d+ "
r"(?(3)required )positional arguments?"
)
if len(e.args) >= 1 and re.search(p_err, e.args[0]):
# FIXME: this should be totally avoidable
raise e
def g(x):
try:
return f(x)
except (TypeError, AttributeError):
return na_value
return _map(g, arr, dtype=dtype)
if na_value is not np.nan:
np.putmask(result, mask, na_value)
if result.dtype == object:
result = lib.maybe_convert_objects(result)
return result
else:
return lib.map_infer(arr, f)
def str_count(arr, pat, flags=0):
"""
Count occurrences of pattern in each string of the Series/Index.
This function is used to count the number of times a particular regex
pattern is repeated in each of the string elements of the
:class:`~pandas.Series`.
Parameters
----------
pat : str
Valid regular expression.
flags : int, default 0, meaning no flags
Flags for the `re` module. For a complete list, `see here
<https://docs.python.org/3/howto/regex.html#compilation-flags>`_.
**kwargs
For compatibility with other string methods. Not used.
Returns
-------
Series or Index
Same type as the calling object containing the integer counts.
See Also
--------
re : Standard library module for regular expressions.
str.count : Standard library version, without regular expression support.
Notes
-----
Some characters need to be escaped when passing in `pat`.
eg. ``'$'`` has a special meaning in regex and must be escaped when
finding this literal character.
Examples
--------
>>> s = pd.Series(['A', 'B', 'Aaba', 'Baca', np.nan, 'CABA', 'cat'])
>>> s.str.count('a')
0 0.0
1 0.0
2 2.0
3 2.0
4 NaN
5 0.0
6 1.0
dtype: float64
Escape ``'$'`` to find the literal dollar sign.
>>> s = pd.Series(['$', 'B', 'Aab$', '$$ca', 'C$B$', 'cat'])
>>> s.str.count('\\$')
0 1
1 0
2 1
3 2
4 2
5 0
dtype: int64
This is also available on Index
>>> pd.Index(['A', 'A', 'Aaba', 'cat']).str.count('a')
Int64Index([0, 0, 2, 1], dtype='int64')
"""
regex = re.compile(pat, flags=flags)
f = lambda x: len(regex.findall(x))
return _na_map(f, arr, dtype=int)
def str_contains(arr, pat, case=True, flags=0, na=np.nan, regex=True):
"""
Test if pattern or regex is contained within a string of a Series or Index.
Return boolean Series or Index based on whether a given pattern or regex is
contained within a string of a Series or Index.
Parameters
----------
pat : str
Character sequence or regular expression.
case : bool, default True
If True, case sensitive.
flags : int, default 0 (no flags)
Flags to pass through to the re module, e.g. re.IGNORECASE.
na : default NaN
Fill value for missing values.
regex : bool, default True
If True, assumes the pat is a regular expression.
If False, treats the pat as a literal string.
Returns
-------
Series or Index of boolean values
A Series or Index of boolean values indicating whether the
given pattern is contained within the string of each element
of the Series or Index.
See Also
--------
match : Analogous, but stricter, relying on re.match instead of re.search.
Series.str.startswith : Test if the start of each string element matches a
pattern.
Series.str.endswith : Same as startswith, but tests the end of string.
Examples
--------
Returning a Series of booleans using only a literal pattern.
>>> s1 = pd.Series(['Mouse', 'dog', 'house and parrot', '23', np.NaN])
>>> s1.str.contains('og', regex=False)
0 False
1 True
2 False
3 False
4 NaN
dtype: object
Returning an Index of booleans using only a literal pattern.
>>> ind = pd.Index(['Mouse', 'dog', 'house and parrot', '23.0', np.NaN])
>>> ind.str.contains('23', regex=False)
Index([False, False, False, True, nan], dtype='object')
Specifying case sensitivity using `case`.
>>> s1.str.contains('oG', case=True, regex=True)
0 False
1 False
2 False
3 False
4 NaN
dtype: object
Specifying `na` to be `False` instead of `NaN` replaces NaN values
with `False`. If Series or Index does not contain NaN values
the resultant dtype will be `bool`, otherwise, an `object` dtype.
>>> s1.str.contains('og', na=False, regex=True)
0 False
1 True
2 False
3 False
4 False
dtype: bool
Returning 'house' or 'dog' when either expression occurs in a string.
>>> s1.str.contains('house|dog', regex=True)
0 False
1 True
2 True
3 False
4 NaN
dtype: object
Ignoring case sensitivity using `flags` with regex.
>>> import re
>>> s1.str.contains('PARROT', flags=re.IGNORECASE, regex=True)
0 False
1 False
2 True
3 False
4 NaN
dtype: object
Returning any digit using regular expression.
>>> s1.str.contains('\\d', regex=True)
0 False
1 False
2 False
3 True
4 NaN
dtype: object
Ensure `pat` is a not a literal pattern when `regex` is set to True.
Note in the following example one might expect only `s2[1]` and `s2[3]` to
return `True`. However, '.0' as a regex matches any character
followed by a 0.
>>> s2 = pd.Series(['40', '40.0', '41', '41.0', '35'])
>>> s2.str.contains('.0', regex=True)
0 True
1 True
2 False
3 True
4 False
dtype: bool
"""
if regex:
if not case:
flags |= re.IGNORECASE
regex = re.compile(pat, flags=flags)
if regex.groups > 0:
warnings.warn(
"This pattern has match groups. To actually get the"
" groups, use str.extract.",
UserWarning,
stacklevel=3,
)
f = lambda x: bool(regex.search(x))
else:
if case:
f = lambda x: pat in x
else:
upper_pat = pat.upper()
f = lambda x: upper_pat in x
uppered = _na_map(lambda x: x.upper(), arr)
return _na_map(f, uppered, na, dtype=bool)
return _na_map(f, arr, na, dtype=bool)
def str_startswith(arr, pat, na=np.nan):
"""
Test if the start of each string element matches a pattern.
Equivalent to :meth:`str.startswith`.
Parameters
----------
pat : str
Character sequence. Regular expressions are not accepted.
na : object, default NaN
Object shown if element tested is not a string.
Returns
-------
Series or Index of bool
A Series of booleans indicating whether the given pattern matches
the start of each string element.
See Also
--------
str.startswith : Python standard library string method.
Series.str.endswith : Same as startswith, but tests the end of string.
Series.str.contains : Tests if string element contains a pattern.
Examples
--------
>>> s = pd.Series(['bat', 'Bear', 'cat', np.nan])
>>> s
0 bat
1 Bear
2 cat
3 NaN
dtype: object
>>> s.str.startswith('b')
0 True
1 False
2 False
3 NaN
dtype: object
Specifying `na` to be `False` instead of `NaN`.
>>> s.str.startswith('b', na=False)
0 True
1 False
2 False
3 False
dtype: bool
"""
f = lambda x: x.startswith(pat)
return _na_map(f, arr, na, dtype=bool)
def str_endswith(arr, pat, na=np.nan):
"""
Test if the end of each string element matches a pattern.
Equivalent to :meth:`str.endswith`.
Parameters
----------
pat : str
Character sequence. Regular expressions are not accepted.
na : object, default NaN
Object shown if element tested is not a string.
Returns
-------
Series or Index of bool
A Series of booleans indicating whether the given pattern matches
the end of each string element.
See Also
--------
str.endswith : Python standard library string method.
Series.str.startswith : Same as endswith, but tests the start of string.
Series.str.contains : Tests if string element contains a pattern.
Examples
--------
>>> s = pd.Series(['bat', 'bear', 'caT', np.nan])
>>> s
0 bat
1 bear
2 caT
3 NaN
dtype: object
>>> s.str.endswith('t')
0 True
1 False
2 False
3 NaN
dtype: object
Specifying `na` to be `False` instead of `NaN`.
>>> s.str.endswith('t', na=False)
0 True
1 False
2 False
3 False
dtype: bool
"""
f = lambda x: x.endswith(pat)
return _na_map(f, arr, na, dtype=bool)
def str_replace(arr, pat, repl, n=-1, case=None, flags=0, regex=True):
r"""
Replace occurrences of pattern/regex in the Series/Index with
some other string. Equivalent to :meth:`str.replace` or
:func:`re.sub`.
Parameters
----------
pat : str or compiled regex
String can be a character sequence or regular expression.
repl : str or callable
Replacement string or a callable. The callable is passed the regex
match object and must return a replacement string to be used.
See :func:`re.sub`.
n : int, default -1 (all)
Number of replacements to make from start.
case : bool, default None
Determines if replace is case sensitive:
- If True, case sensitive (the default if `pat` is a string)
- Set to False for case insensitive
- Cannot be set if `pat` is a compiled regex.
flags : int, default 0 (no flags)
Regex module flags, e.g. re.IGNORECASE. Cannot be set if `pat` is a compiled
regex.
regex : bool, default True
Determines if assumes the passed-in pattern is a regular expression:
- If True, assumes the passed-in pattern is a regular expression.
- If False, treats the pattern as a literal string
- Cannot be set to False if `pat` is a compiled regex or `repl` is
a callable.
.. versionadded:: 0.23.0
Returns
-------
Series or Index of object
A copy of the object with all matching occurrences of `pat` replaced by
`repl`.
Raises
------
ValueError
* if `regex` is False and `repl` is a callable or `pat` is a compiled
regex
* if `pat` is a compiled regex and `case` or `flags` is set
Notes
-----
When `pat` is a compiled regex, all flags should be included in the
compiled regex. Use of `case`, `flags`, or `regex=False` with a compiled
regex will raise an error.
Examples
--------
When `pat` is a string and `regex` is True (the default), the given `pat`
is compiled as a regex. When `repl` is a string, it replaces matching
regex patterns as with :meth:`re.sub`. NaN value(s) in the Series are
left as is:
>>> pd.Series(['foo', 'fuz', np.nan]).str.replace('f.', 'ba', regex=True)
0 bao
1 baz
2 NaN
dtype: object
When `pat` is a string and `regex` is False, every `pat` is replaced with
`repl` as with :meth:`str.replace`:
>>> pd.Series(['f.o', 'fuz', np.nan]).str.replace('f.', 'ba', regex=False)
0 bao
1 fuz
2 NaN
dtype: object
When `repl` is a callable, it is called on every `pat` using
:func:`re.sub`. The callable should expect one positional argument
(a regex object) and return a string.
To get the idea:
>>> pd.Series(['foo', 'fuz', np.nan]).str.replace('f', repr)
0 <_sre.SRE_Match object; span=(0, 1), match='f'>oo
1 <_sre.SRE_Match object; span=(0, 1), match='f'>uz
2 NaN
dtype: object
Reverse every lowercase alphabetic word:
>>> repl = lambda m: m.group(0)[::-1]
>>> pd.Series(['foo 123', 'bar baz', np.nan]).str.replace(r'[a-z]+', repl)
0 oof 123
1 rab zab
2 NaN
dtype: object
Using regex groups (extract second group and swap case):
>>> pat = r"(?P<one>\w+) (?P<two>\w+) (?P<three>\w+)"
>>> repl = lambda m: m.group('two').swapcase()
>>> pd.Series(['One Two Three', 'Foo Bar Baz']).str.replace(pat, repl)
0 tWO
1 bAR
dtype: object
Using a compiled regex with flags
>>> import re
>>> regex_pat = re.compile(r'FUZ', flags=re.IGNORECASE)
>>> pd.Series(['foo', 'fuz', np.nan]).str.replace(regex_pat, 'bar')
0 foo
1 bar
2 NaN
dtype: object
"""
# Check whether repl is valid (GH 13438, GH 15055)
if not (isinstance(repl, str) or callable(repl)):
raise TypeError("repl must be a string or callable")
is_compiled_re = is_re(pat)
if regex:
if is_compiled_re:
if (case is not None) or (flags != 0):
raise ValueError(
"case and flags cannot be set when pat is a compiled regex"
)
else:
# not a compiled regex
# set default case
if case is None:
case = True
# add case flag, if provided
if case is False:
flags |= re.IGNORECASE
if is_compiled_re or len(pat) > 1 or flags or callable(repl):
n = n if n >= 0 else 0
compiled = re.compile(pat, flags=flags)
f = lambda x: compiled.sub(repl=repl, string=x, count=n)
else:
f = lambda x: x.replace(pat, repl, n)
else:
if is_compiled_re:
raise ValueError(
"Cannot use a compiled regex as replacement pattern with regex=False"
)
if callable(repl):
raise ValueError("Cannot use a callable replacement when regex=False")
f = lambda x: x.replace(pat, repl, n)
return _na_map(f, arr)
def str_repeat(arr, repeats):
"""
Duplicate each string in the Series or Index.
Parameters
----------
repeats : int or sequence of int
Same value for all (int) or different value per (sequence).
Returns
-------
Series or Index of object
Series or Index of repeated string objects specified by
input parameter repeats.
Examples
--------
>>> s = pd.Series(['a', 'b', 'c'])
>>> s
0 a
1 b
2 c
dtype: object
Single int repeats string in Series
>>> s.str.repeat(repeats=2)
0 aa
1 bb
2 cc
dtype: object
Sequence of int repeats corresponding string in Series
>>> s.str.repeat(repeats=[1, 2, 3])
0 a
1 bb
2 ccc
dtype: object
"""
if is_scalar(repeats):
def scalar_rep(x):
try:
return bytes.__mul__(x, repeats)
except TypeError:
return str.__mul__(x, repeats)
return _na_map(scalar_rep, arr)
else:
def rep(x, r):
try:
return bytes.__mul__(x, r)
except TypeError:
return str.__mul__(x, r)
repeats = np.asarray(repeats, dtype=object)
result = libops.vec_binop(com.values_from_object(arr), repeats, rep)
return result
def str_match(arr, pat, case=True, flags=0, na=np.nan):
"""
Determine if each string matches a regular expression.
Parameters
----------
pat : str
Character sequence or regular expression.
case : bool, default True
If True, case sensitive.
flags : int, default 0 (no flags)
Regex module flags, e.g. re.IGNORECASE.
na : default NaN
Fill value for missing values.
Returns
-------
Series/array of boolean values
See Also
--------
contains : Analogous, but less strict, relying on re.search instead of
re.match.
extract : Extract matched groups.
"""
if not case:
flags |= re.IGNORECASE
regex = re.compile(pat, flags=flags)
dtype = bool
f = lambda x: bool(regex.match(x))
return _na_map(f, arr, na, dtype=dtype)
def _get_single_group_name(rx):
try:
return list(rx.groupindex.keys()).pop()
except IndexError:
return None
def _groups_or_na_fun(regex):
"""Used in both extract_noexpand and extract_frame"""
if regex.groups == 0:
raise ValueError("pattern contains no capture groups")
empty_row = [np.nan] * regex.groups
def f(x):
if not isinstance(x, str):
return empty_row
m = regex.search(x)
if m:
return [np.nan if item is None else item for item in m.groups()]
else:
return empty_row
return f
def _result_dtype(arr):
# workaround #27953
# ideally we just pass `dtype=arr.dtype` unconditionally, but this fails
# when the list of values is empty.
if arr.dtype.name == "string":
return "string"
else:
return object
def _str_extract_noexpand(arr, pat, flags=0):
"""
Find groups in each string in the Series using passed regular
expression. This function is called from
str_extract(expand=False), and can return Series, DataFrame, or
Index.
"""
from pandas import DataFrame
regex = re.compile(pat, flags=flags)
groups_or_na = _groups_or_na_fun(regex)
if regex.groups == 1:
result = np.array([groups_or_na(val)[0] for val in arr], dtype=object)
name = _get_single_group_name(regex)
else:
if isinstance(arr, ABCIndexClass):
raise ValueError("only one regex group is supported with Index")
name = None
names = dict(zip(regex.groupindex.values(), regex.groupindex.keys()))
columns = [names.get(1 + i, i) for i in range(regex.groups)]
if arr.empty:
result = DataFrame(columns=columns, dtype=object)
else:
result = DataFrame(
[groups_or_na(val) for val in arr],
columns=columns,
index=arr.index,
dtype=object,
)
return result, name
def _str_extract_frame(arr, pat, flags=0):
"""
For each subject string in the Series, extract groups from the
first match of regular expression pat. This function is called from
str_extract(expand=True), and always returns a DataFrame.
"""
from pandas import DataFrame
regex = re.compile(pat, flags=flags)
groups_or_na = _groups_or_na_fun(regex)
names = dict(zip(regex.groupindex.values(), regex.groupindex.keys()))
columns = [names.get(1 + i, i) for i in range(regex.groups)]
if len(arr) == 0:
return DataFrame(columns=columns, dtype=object)
try:
result_index = arr.index
except AttributeError:
result_index = None
dtype = _result_dtype(arr)
return DataFrame(
[groups_or_na(val) for val in arr],
columns=columns,
index=result_index,
dtype=dtype,
)
def str_extract(arr, pat, flags=0, expand=True):
r"""
Extract capture groups in the regex `pat` as columns in a DataFrame.
For each subject string in the Series, extract groups from the
first match of regular expression `pat`.
Parameters
----------
pat : str
Regular expression pattern with capturing groups.
flags : int, default 0 (no flags)
Flags from the ``re`` module, e.g. ``re.IGNORECASE``, that
modify regular expression matching for things like case,
spaces, etc. For more details, see :mod:`re`.
expand : bool, default True
If True, return DataFrame with one column per capture group.
If False, return a Series/Index if there is one capture group
or DataFrame if there are multiple capture groups.
Returns
-------
DataFrame or Series or Index
A DataFrame with one row for each subject string, and one
column for each group. Any capture group names in regular
expression pat will be used for column names; otherwise
capture group numbers will be used. The dtype of each result
column is always object, even when no match is found. If
``expand=False`` and pat has only one capture group, then
return a Series (if subject is a Series) or Index (if subject
is an Index).
See Also
--------
extractall : Returns all matches (not just the first match).
Examples
--------
A pattern with two groups will return a DataFrame with two columns.
Non-matches will be NaN.
>>> s = pd.Series(['a1', 'b2', 'c3'])
>>> s.str.extract(r'([ab])(\d)')
0 1
0 a 1
1 b 2
2 NaN NaN
A pattern may contain optional groups.
>>> s.str.extract(r'([ab])?(\d)')
0 1
0 a 1
1 b 2
2 NaN 3
Named groups will become column names in the result.
>>> s.str.extract(r'(?P<letter>[ab])(?P<digit>\d)')
letter digit
0 a 1
1 b 2
2 NaN NaN
A pattern with one group will return a DataFrame with one column
if expand=True.
>>> s.str.extract(r'[ab](\d)', expand=True)
0
0 1
1 2
2 NaN
A pattern with one group will return a Series if expand=False.
>>> s.str.extract(r'[ab](\d)', expand=False)
0 1
1 2
2 NaN
dtype: object
"""
if not isinstance(expand, bool):
raise ValueError("expand must be True or False")
if expand:
return _str_extract_frame(arr._orig, pat, flags=flags)
else:
result, name = _str_extract_noexpand(arr._parent, pat, flags=flags)
return arr._wrap_result(result, name=name, expand=expand)
def str_extractall(arr, pat, flags=0):
r"""
For each subject string in the Series, extract groups from all
matches of regular expression pat. When each subject string in the
Series has exactly one match, extractall(pat).xs(0, level='match')
is the same as extract(pat).
Parameters
----------
pat : str
Regular expression pattern with capturing groups.
flags : int, default 0 (no flags)
A ``re`` module flag, for example ``re.IGNORECASE``. These allow
to modify regular expression matching for things like case, spaces,
etc. Multiple flags can be combined with the bitwise OR operator,
for example ``re.IGNORECASE | re.MULTILINE``.
Returns
-------
DataFrame
A ``DataFrame`` with one row for each match, and one column for each
group. Its rows have a ``MultiIndex`` with first levels that come from
the subject ``Series``. The last level is named 'match' and indexes the
matches in each item of the ``Series``. Any capture group names in
regular expression pat will be used for column names; otherwise capture
group numbers will be used.
See Also
--------
extract : Returns first match only (not all matches).
Examples
--------
A pattern with one group will return a DataFrame with one column.
Indices with no matches will not appear in the result.
>>> s = pd.Series(["a1a2", "b1", "c1"], index=["A", "B", "C"])
>>> s.str.extractall(r"[ab](\d)")
0
match
A 0 1
1 2
B 0 1
Capture group names are used for column names of the result.
>>> s.str.extractall(r"[ab](?P<digit>\d)")
digit
match
A 0 1
1 2
B 0 1
A pattern with two groups will return a DataFrame with two columns.
>>> s.str.extractall(r"(?P<letter>[ab])(?P<digit>\d)")
letter digit
match
A 0 a 1
1 a 2
B 0 b 1
Optional groups that do not match are NaN in the result.
>>> s.str.extractall(r"(?P<letter>[ab])?(?P<digit>\d)")
letter digit
match
A 0 a 1
1 a 2
B 0 b 1
C 0 NaN 1
"""
regex = re.compile(pat, flags=flags)
# the regex must contain capture groups.
if regex.groups == 0:
raise ValueError("pattern contains no capture groups")
if isinstance(arr, ABCIndexClass):
arr = arr.to_series().reset_index(drop=True)
names = dict(zip(regex.groupindex.values(), regex.groupindex.keys()))
columns = [names.get(1 + i, i) for i in range(regex.groups)]
match_list = []
index_list = []
is_mi = arr.index.nlevels > 1
for subject_key, subject in arr.items():
if isinstance(subject, str):
if not is_mi:
subject_key = (subject_key,)
for match_i, match_tuple in enumerate(regex.findall(subject)):
if isinstance(match_tuple, str):
match_tuple = (match_tuple,)
na_tuple = [np.NaN if group == "" else group for group in match_tuple]
match_list.append(na_tuple)
result_key = tuple(subject_key + (match_i,))
index_list.append(result_key)
from pandas import MultiIndex
index = MultiIndex.from_tuples(index_list, names=arr.index.names + ["match"])
dtype = _result_dtype(arr)
result = arr._constructor_expanddim(
match_list, index=index, columns=columns, dtype=dtype
)
return result
def str_get_dummies(arr, sep="|"):
"""
Split each string in the Series by sep and return a DataFrame
of dummy/indicator variables.
Parameters
----------
sep : str, default "|"
String to split on.
Returns
-------
DataFrame
Dummy variables corresponding to values of the Series.
See Also
--------
get_dummies : Convert categorical variable into dummy/indicator
variables.
Examples
--------
>>> pd.Series(['a|b', 'a', 'a|c']).str.get_dummies()
a b c
0 1 1 0
1 1 0 0
2 1 0 1
>>> pd.Series(['a|b', np.nan, 'a|c']).str.get_dummies()
a b c
0 1 1 0
1 0 0 0
2 1 0 1
"""
arr = arr.fillna("")
try:
arr = sep + arr + sep
except TypeError:
arr = sep + arr.astype(str) + sep
tags = set()
for ts in arr.str.split(sep):
tags.update(ts)
tags = sorted(tags - {""})
dummies = np.empty((len(arr), len(tags)), dtype=np.int64)
for i, t in enumerate(tags):
pat = sep + t + sep
dummies[:, i] = lib.map_infer(arr.to_numpy(), lambda x: pat in x)
return dummies, tags
def str_join(arr, sep):
"""
Join lists contained as elements in the Series/Index with passed delimiter.
If the elements of a Series are lists themselves, join the content of these
lists using the delimiter passed to the function.
This function is an equivalent to :meth:`str.join`.
Parameters
----------
sep : str
Delimiter to use between list entries.
Returns
-------
Series/Index: object
The list entries concatenated by intervening occurrences of the
delimiter.
Raises
------
AttributeError
If the supplied Series contains neither strings nor lists.
See Also
--------
str.join : Standard library version of this method.
Series.str.split : Split strings around given separator/delimiter.
Notes
-----
If any of the list items is not a string object, the result of the join
will be `NaN`.
Examples
--------
Example with a list that contains non-string elements.
>>> s = pd.Series([['lion', 'elephant', 'zebra'],
... [1.1, 2.2, 3.3],
... ['cat', np.nan, 'dog'],
... ['cow', 4.5, 'goat'],
... ['duck', ['swan', 'fish'], 'guppy']])
>>> s
0 [lion, elephant, zebra]
1 [1.1, 2.2, 3.3]
2 [cat, nan, dog]
3 [cow, 4.5, goat]
4 [duck, [swan, fish], guppy]
dtype: object
Join all lists using a '-'. The lists containing object(s) of types other
than str will produce a NaN.
>>> s.str.join('-')
0 lion-elephant-zebra
1 NaN
2 NaN
3 NaN
4 NaN
dtype: object
"""
return _na_map(sep.join, arr)
def str_findall(arr, pat, flags=0):
"""
Find all occurrences of pattern or regular expression in the Series/Index.
Equivalent to applying :func:`re.findall` to all the elements in the
Series/Index.
Parameters
----------
pat : str
Pattern or regular expression.
flags : int, default 0
Flags from ``re`` module, e.g. `re.IGNORECASE` (default is 0, which
means no flags).
Returns
-------
Series/Index of lists of strings
All non-overlapping matches of pattern or regular expression in each
string of this Series/Index.
See Also
--------
count : Count occurrences of pattern or regular expression in each string
of the Series/Index.
extractall : For each string in the Series, extract groups from all matches
of regular expression and return a DataFrame with one row for each
match and one column for each group.
re.findall : The equivalent ``re`` function to all non-overlapping matches
of pattern or regular expression in string, as a list of strings.
Examples
--------
>>> s = pd.Series(['Lion', 'Monkey', 'Rabbit'])
The search for the pattern 'Monkey' returns one match:
>>> s.str.findall('Monkey')
0 []
1 [Monkey]
2 []
dtype: object
On the other hand, the search for the pattern 'MONKEY' doesn't return any
match:
>>> s.str.findall('MONKEY')
0 []
1 []
2 []
dtype: object
Flags can be added to the pattern or regular expression. For instance,
to find the pattern 'MONKEY' ignoring the case:
>>> import re
>>> s.str.findall('MONKEY', flags=re.IGNORECASE)
0 []
1 [Monkey]
2 []
dtype: object
When the pattern matches more than one string in the Series, all matches
are returned:
>>> s.str.findall('on')
0 [on]
1 [on]
2 []
dtype: object
Regular expressions are supported too. For instance, the search for all the
strings ending with the word 'on' is shown next:
>>> s.str.findall('on$')
0 [on]
1 []
2 []
dtype: object
If the pattern is found more than once in the same string, then a list of
multiple strings is returned:
>>> s.str.findall('b')
0 []
1 []
2 [b, b]
dtype: object
"""
regex = re.compile(pat, flags=flags)
return _na_map(regex.findall, arr)
def str_find(arr, sub, start=0, end=None, side="left"):
"""
Return indexes in each strings in the Series/Index where the
substring is fully contained between [start:end]. Return -1 on failure.
Parameters
----------
sub : str
Substring being searched.
start : int
Left edge index.
end : int
Right edge index.
side : {'left', 'right'}, default 'left'
Specifies a starting side, equivalent to ``find`` or ``rfind``.
Returns
-------
Series or Index
Indexes where substring is found.
"""
if not isinstance(sub, str):
msg = "expected a string object, not {0}"
raise TypeError(msg.format(type(sub).__name__))
if side == "left":
method = "find"
elif side == "right":
method = "rfind"
else: # pragma: no cover
raise ValueError("Invalid side")
if end is None:
f = lambda x: getattr(x, method)(sub, start)
else:
f = lambda x: getattr(x, method)(sub, start, end)
return _na_map(f, arr, dtype=int)
def str_index(arr, sub, start=0, end=None, side="left"):
if not isinstance(sub, str):
msg = "expected a string object, not {0}"
raise TypeError(msg.format(type(sub).__name__))
if side == "left":
method = "index"
elif side == "right":
method = "rindex"
else: # pragma: no cover
raise ValueError("Invalid side")
if end is None:
f = lambda x: getattr(x, method)(sub, start)
else:
f = lambda x: getattr(x, method)(sub, start, end)
return _na_map(f, arr, dtype=int)
def str_pad(arr, width, side="left", fillchar=" "):
"""
Pad strings in the Series/Index up to width.
Parameters
----------
width : int
Minimum width of resulting string; additional characters will be filled
with character defined in `fillchar`.
side : {'left', 'right', 'both'}, default 'left'
Side from which to fill resulting string.
fillchar : str, default ' '
Additional character for filling, default is whitespace.
Returns
-------
Series or Index of object
Returns Series or Index with minimum number of char in object.
See Also
--------
Series.str.rjust : Fills the left side of strings with an arbitrary
character. Equivalent to ``Series.str.pad(side='left')``.
Series.str.ljust : Fills the right side of strings with an arbitrary
character. Equivalent to ``Series.str.pad(side='right')``.
Series.str.center : Fills boths sides of strings with an arbitrary
character. Equivalent to ``Series.str.pad(side='both')``.
Series.str.zfill : Pad strings in the Series/Index by prepending '0'
character. Equivalent to ``Series.str.pad(side='left', fillchar='0')``.
Examples
--------
>>> s = pd.Series(["caribou", "tiger"])
>>> s
0 caribou
1 tiger
dtype: object
>>> s.str.pad(width=10)
0 caribou
1 tiger
dtype: object
>>> s.str.pad(width=10, side='right', fillchar='-')
0 caribou---
1 tiger-----
dtype: object
>>> s.str.pad(width=10, side='both', fillchar='-')
0 -caribou--
1 --tiger---
dtype: object
"""
if not isinstance(fillchar, str):
msg = "fillchar must be a character, not {0}"
raise TypeError(msg.format(type(fillchar).__name__))
if len(fillchar) != 1:
raise TypeError("fillchar must be a character, not str")
if not is_integer(width):
msg = "width must be of integer type, not {0}"
raise TypeError(msg.format(type(width).__name__))
if side == "left":
f = lambda x: x.rjust(width, fillchar)
elif side == "right":
f = lambda x: x.ljust(width, fillchar)
elif side == "both":
f = lambda x: x.center(width, fillchar)
else: # pragma: no cover
raise ValueError("Invalid side")
return _na_map(f, arr)
def str_split(arr, pat=None, n=None):
if pat is None:
if n is None or n == 0:
n = -1
f = lambda x: x.split(pat, n)
else:
if len(pat) == 1:
if n is None or n == 0:
n = -1
f = lambda x: x.split(pat, n)
else:
if n is None or n == -1:
n = 0
regex = re.compile(pat)
f = lambda x: regex.split(x, maxsplit=n)
res = _na_map(f, arr)
return res
def str_rsplit(arr, pat=None, n=None):
if n is None or n == 0:
n = -1
f = lambda x: x.rsplit(pat, n)
res = _na_map(f, arr)
return res
def str_slice(arr, start=None, stop=None, step=None):
"""
Slice substrings from each element in the Series or Index.
Parameters
----------
start : int, optional
Start position for slice operation.
stop : int, optional
Stop position for slice operation.
step : int, optional
Step size for slice operation.
Returns
-------
Series or Index of object
Series or Index from sliced substring from original string object.
See Also
--------
Series.str.slice_replace : Replace a slice with a string.
Series.str.get : Return element at position.
Equivalent to `Series.str.slice(start=i, stop=i+1)` with `i`
being the position.
Examples
--------
>>> s = pd.Series(["koala", "fox", "chameleon"])
>>> s
0 koala
1 fox
2 chameleon
dtype: object
>>> s.str.slice(start=1)
0 oala
1 ox
2 hameleon
dtype: object
>>> s.str.slice(start=-1)
0 a
1 x
2 n
dtype: object
>>> s.str.slice(stop=2)
0 ko
1 fo
2 ch
dtype: object
>>> s.str.slice(step=2)
0 kaa
1 fx
2 caeen
dtype: object
>>> s.str.slice(start=0, stop=5, step=3)
0 kl
1 f
2 cm
dtype: object
Equivalent behaviour to:
>>> s.str[0:5:3]
0 kl
1 f
2 cm
dtype: object
"""
obj = slice(start, stop, step)
f = lambda x: x[obj]
return _na_map(f, arr)
def str_slice_replace(arr, start=None, stop=None, repl=None):
"""
Replace a positional slice of a string with another value.
Parameters
----------
start : int, optional
Left index position to use for the slice. If not specified (None),
the slice is unbounded on the left, i.e. slice from the start
of the string.
stop : int, optional
Right index position to use for the slice. If not specified (None),
the slice is unbounded on the right, i.e. slice until the
end of the string.
repl : str, optional
String for replacement. If not specified (None), the sliced region
is replaced with an empty string.
Returns
-------
Series or Index
Same type as the original object.
See Also
--------
Series.str.slice : Just slicing without replacement.
Examples
--------
>>> s = pd.Series(['a', 'ab', 'abc', 'abdc', 'abcde'])
>>> s
0 a
1 ab
2 abc
3 abdc
4 abcde
dtype: object
Specify just `start`, meaning replace `start` until the end of the
string with `repl`.
>>> s.str.slice_replace(1, repl='X')
0 aX
1 aX
2 aX
3 aX
4 aX
dtype: object
Specify just `stop`, meaning the start of the string to `stop` is replaced
with `repl`, and the rest of the string is included.
>>> s.str.slice_replace(stop=2, repl='X')
0 X
1 X
2 Xc
3 Xdc
4 Xcde
dtype: object
Specify `start` and `stop`, meaning the slice from `start` to `stop` is
replaced with `repl`. Everything before or after `start` and `stop` is
included as is.
>>> s.str.slice_replace(start=1, stop=3, repl='X')
0 aX
1 aX
2 aX
3 aXc
4 aXde
dtype: object
"""
if repl is None:
repl = ""
def f(x):
if x[start:stop] == "":
local_stop = start
else:
local_stop = stop
y = ""
if start is not None:
y += x[:start]
y += repl
if stop is not None:
y += x[local_stop:]
return y
return _na_map(f, arr)
def str_strip(arr, to_strip=None, side="both"):
"""
Strip whitespace (including newlines) from each string in the
Series/Index.
Parameters
----------
to_strip : str or unicode
side : {'left', 'right', 'both'}, default 'both'
Returns
-------
Series or Index
"""
if side == "both":
f = lambda x: x.strip(to_strip)
elif side == "left":
f = lambda x: x.lstrip(to_strip)
elif side == "right":
f = lambda x: x.rstrip(to_strip)
else: # pragma: no cover
raise ValueError("Invalid side")
return _na_map(f, arr)
def str_wrap(arr, width, **kwargs):
r"""
Wrap long strings in the Series/Index to be formatted in
paragraphs with length less than a given width.
This method has the same keyword parameters and defaults as
:class:`textwrap.TextWrapper`.
Parameters
----------
width : int
Maximum line width.
expand_tabs : bool, optional
If True, tab characters will be expanded to spaces (default: True).
replace_whitespace : bool, optional
If True, each whitespace character (as defined by string.whitespace)
remaining after tab expansion will be replaced by a single space
(default: True).
drop_whitespace : bool, optional
If True, whitespace that, after wrapping, happens to end up at the
beginning or end of a line is dropped (default: True).
break_long_words : bool, optional
If True, then words longer than width will be broken in order to ensure
that no lines are longer than width. If it is false, long words will
not be broken, and some lines may be longer than width (default: True).
break_on_hyphens : bool, optional
If True, wrapping will occur preferably on whitespace and right after
hyphens in compound words, as it is customary in English. If false,
only whitespaces will be considered as potentially good places for line
breaks, but you need to set break_long_words to false if you want truly
insecable words (default: True).
Returns
-------
Series or Index
Notes
-----
Internally, this method uses a :class:`textwrap.TextWrapper` instance with
default settings. To achieve behavior matching R's stringr library str_wrap
function, use the arguments:
- expand_tabs = False
- replace_whitespace = True
- drop_whitespace = True
- break_long_words = False
- break_on_hyphens = False
Examples
--------
>>> s = pd.Series(['line to be wrapped', 'another line to be wrapped'])
>>> s.str.wrap(12)
0 line to be\nwrapped
1 another line\nto be\nwrapped
dtype: object
"""
kwargs["width"] = width
tw = textwrap.TextWrapper(**kwargs)
return _na_map(lambda s: "\n".join(tw.wrap(s)), arr)
def str_translate(arr, table):
"""
Map all characters in the string through the given mapping table.
Equivalent to standard :meth:`str.translate`.
Parameters
----------
table : dict
Table is a mapping of Unicode ordinals to Unicode ordinals, strings, or
None. Unmapped characters are left untouched.
Characters mapped to None are deleted. :meth:`str.maketrans` is a
helper function for making translation tables.
Returns
-------
Series or Index
"""
return _na_map(lambda x: x.translate(table), arr)
def str_get(arr, i):
"""
Extract element from each component at specified position.
Extract element from lists, tuples, or strings in each element in the
Series/Index.
Parameters
----------
i : int
Position of element to extract.
Returns
-------
Series or Index
Examples
--------
>>> s = pd.Series(["String",
... (1, 2, 3),
... ["a", "b", "c"],
... 123,
... -456,
... {1: "Hello", "2": "World"}])
>>> s
0 String
1 (1, 2, 3)
2 [a, b, c]
3 123
4 -456
5 {1: 'Hello', '2': 'World'}
dtype: object
>>> s.str.get(1)
0 t
1 2
2 b
3 NaN
4 NaN
5 Hello
dtype: object
>>> s.str.get(-1)
0 g
1 3
2 c
3 NaN
4 NaN
5 None
dtype: object
"""
def f(x):
if isinstance(x, dict):
return x.get(i)
elif len(x) > i >= -len(x):
return x[i]
return np.nan
return _na_map(f, arr)
def str_decode(arr, encoding, errors="strict"):
"""
Decode character string in the Series/Index using indicated encoding.
Equivalent to :meth:`str.decode` in python2 and :meth:`bytes.decode` in
python3.
Parameters
----------
encoding : str
errors : str, optional
Returns
-------
Series or Index
"""
if encoding in _cpython_optimized_decoders:
# CPython optimized implementation
f = lambda x: x.decode(encoding, errors)
else:
decoder = codecs.getdecoder(encoding)
f = lambda x: decoder(x, errors)[0]
return _na_map(f, arr)
def str_encode(arr, encoding, errors="strict"):
"""
Encode character string in the Series/Index using indicated encoding.
Equivalent to :meth:`str.encode`.
Parameters
----------
encoding : str
errors : str, optional
Returns
-------
encoded : Series/Index of objects
"""
if encoding in _cpython_optimized_encoders:
# CPython optimized implementation
f = lambda x: x.encode(encoding, errors)
else:
encoder = codecs.getencoder(encoding)
f = lambda x: encoder(x, errors)[0]
return _na_map(f, arr)
def forbid_nonstring_types(forbidden, name=None):
"""
Decorator to forbid specific types for a method of StringMethods.
For calling `.str.{method}` on a Series or Index, it is necessary to first
initialize the :class:`StringMethods` object, and then call the method.
However, different methods allow different input types, and so this can not
be checked during :meth:`StringMethods.__init__`, but must be done on a
per-method basis. This decorator exists to facilitate this process, and
make it explicit which (inferred) types are disallowed by the method.
:meth:`StringMethods.__init__` allows the *union* of types its different
methods allow (after skipping NaNs; see :meth:`StringMethods._validate`),
namely: ['string', 'empty', 'bytes', 'mixed', 'mixed-integer'].
The default string types ['string', 'empty'] are allowed for all methods.
For the additional types ['bytes', 'mixed', 'mixed-integer'], each method
then needs to forbid the types it is not intended for.
Parameters
----------
forbidden : list-of-str or None
List of forbidden non-string types, may be one or more of
`['bytes', 'mixed', 'mixed-integer']`.
name : str, default None
Name of the method to use in the error message. By default, this is
None, in which case the name from the method being wrapped will be
copied. However, for working with further wrappers (like _pat_wrapper
and _noarg_wrapper), it is necessary to specify the name.
Returns
-------
func : wrapper
The method to which the decorator is applied, with an added check that
enforces the inferred type to not be in the list of forbidden types.
Raises
------
TypeError
If the inferred type of the underlying data is in `forbidden`.
"""
# deal with None
forbidden = [] if forbidden is None else forbidden
allowed_types = {"string", "empty", "bytes", "mixed", "mixed-integer"} - set(
forbidden
)
def _forbid_nonstring_types(func):
func_name = func.__name__ if name is None else name
@wraps(func)
def wrapper(self, *args, **kwargs):
if self._inferred_dtype not in allowed_types:
msg = (
"Cannot use .str.{name} with values of inferred dtype "
"{inf_type!r}.".format(
name=func_name, inf_type=self._inferred_dtype
)
)
raise TypeError(msg)
return func(self, *args, **kwargs)
wrapper.__name__ = func_name
return wrapper
return _forbid_nonstring_types
def _noarg_wrapper(
f,
name=None,
docstring=None,
forbidden_types=["bytes"],
returns_string=True,
**kargs,
):
@forbid_nonstring_types(forbidden_types, name=name)
def wrapper(self):
result = _na_map(f, self._parent, **kargs)
return self._wrap_result(result, returns_string=returns_string)
wrapper.__name__ = f.__name__ if name is None else name
if docstring is not None:
wrapper.__doc__ = docstring
else:
raise ValueError("Provide docstring")
return wrapper
def _pat_wrapper(
f,
flags=False,
na=False,
name=None,
forbidden_types=["bytes"],
returns_string=True,
**kwargs,
):
@forbid_nonstring_types(forbidden_types, name=name)
def wrapper1(self, pat):
result = f(self._parent, pat)
return self._wrap_result(result, returns_string=returns_string)
@forbid_nonstring_types(forbidden_types, name=name)
def wrapper2(self, pat, flags=0, **kwargs):
result = f(self._parent, pat, flags=flags, **kwargs)
return self._wrap_result(result, returns_string=returns_string)
@forbid_nonstring_types(forbidden_types, name=name)
def wrapper3(self, pat, na=np.nan):
result = f(self._parent, pat, na=na)
return self._wrap_result(result, returns_string=returns_string)
wrapper = wrapper3 if na else wrapper2 if flags else wrapper1
wrapper.__name__ = f.__name__ if name is None else name
if f.__doc__:
wrapper.__doc__ = f.__doc__
return wrapper
def copy(source):
"Copy a docstring from another source function (if present)"
def do_copy(target):
if source.__doc__:
target.__doc__ = source.__doc__
return target
return do_copy
class StringMethods(NoNewAttributesMixin):
"""
Vectorized string functions for Series and Index. NAs stay NA unless
handled otherwise by a particular method. Patterned after Python's string
methods, with some inspiration from R's stringr package.
Examples
--------
>>> s.str.split('_')
>>> s.str.replace('_', '')
"""
def __init__(self, data):
self._inferred_dtype = self._validate(data)
self._is_categorical = is_categorical_dtype(data)
self._is_string = data.dtype.name == "string"
# .values.categories works for both Series/Index
self._parent = data.values.categories if self._is_categorical else data
# save orig to blow up categoricals to the right type
self._orig = data
self._freeze()
@staticmethod
def _validate(data):
"""
Auxiliary function for StringMethods, infers and checks dtype of data.
This is a "first line of defence" at the creation of the StringMethods-
object (see _make_accessor), and just checks that the dtype is in the
*union* of the allowed types over all string methods below; this
restriction is then refined on a per-method basis using the decorator
@forbid_nonstring_types (more info in the corresponding docstring).
This really should exclude all series/index with any non-string values,
but that isn't practical for performance reasons until we have a str
dtype (GH 9343 / 13877)
Parameters
----------
data : The content of the Series
Returns
-------
dtype : inferred dtype of data
"""
from pandas import StringDtype
if isinstance(data, ABCMultiIndex):
raise AttributeError(
"Can only use .str accessor with Index, not MultiIndex"
)
# see _libs/lib.pyx for list of inferred types
allowed_types = ["string", "empty", "bytes", "mixed", "mixed-integer"]
values = getattr(data, "values", data) # Series / Index
values = getattr(values, "categories", values) # categorical / normal
# explicitly allow StringDtype
if isinstance(values.dtype, StringDtype):
return "string"
try:
inferred_dtype = lib.infer_dtype(values, skipna=True)
except ValueError:
# GH#27571 mostly occurs with ExtensionArray
inferred_dtype = None
if inferred_dtype not in allowed_types:
raise AttributeError("Can only use .str accessor with string values!")
return inferred_dtype
def __getitem__(self, key):
if isinstance(key, slice):
return self.slice(start=key.start, stop=key.stop, step=key.step)
else:
return self.get(key)
def __iter__(self):
i = 0
g = self.get(i)
while g.notna().any():
yield g
i += 1
g = self.get(i)
def _wrap_result(
self,
result,
use_codes=True,
name=None,
expand=None,
fill_value=np.nan,
returns_string=True,
):
from pandas import Index, Series, MultiIndex
# for category, we do the stuff on the categories, so blow it up
# to the full series again
# But for some operations, we have to do the stuff on the full values,
# so make it possible to skip this step as the method already did this
# before the transformation...
if use_codes and self._is_categorical:
# if self._orig is a CategoricalIndex, there is no .cat-accessor
result = take_1d(
result, Series(self._orig, copy=False).cat.codes, fill_value=fill_value
)
if not hasattr(result, "ndim") or not hasattr(result, "dtype"):
return result
assert result.ndim < 3
# We can be wrapping a string / object / categorical result, in which
# case we'll want to return the same dtype as the input.
# Or we can be wrapping a numeric output, in which case we don't want
# to return a StringArray.
if self._is_string and returns_string:
dtype = "string"
else:
dtype = None
if expand is None:
# infer from ndim if expand is not specified
expand = result.ndim != 1
elif expand is True and not isinstance(self._orig, ABCIndexClass):
# required when expand=True is explicitly specified
# not needed when inferred
def cons_row(x):
if is_list_like(x):
return x
else:
return [x]
result = [cons_row(x) for x in result]
if result:
# propagate nan values to match longest sequence (GH 18450)
max_len = max(len(x) for x in result)
result = [
x * max_len if len(x) == 0 or x[0] is np.nan else x for x in result
]
if not isinstance(expand, bool):
raise ValueError("expand must be True or False")
if expand is False:
# if expand is False, result should have the same name
# as the original otherwise specified
if name is None:
name = getattr(result, "name", None)
if name is None:
# do not use logical or, _orig may be a DataFrame
# which has "name" column
name = self._orig.name
# Wait until we are sure result is a Series or Index before
# checking attributes (GH 12180)
if isinstance(self._orig, ABCIndexClass):
# if result is a boolean np.array, return the np.array
# instead of wrapping it into a boolean Index (GH 8875)
if is_bool_dtype(result):
return result
if expand:
result = list(result)
out = MultiIndex.from_tuples(result, names=name)
if out.nlevels == 1:
# We had all tuples of length-one, which are
# better represented as a regular Index.
out = out.get_level_values(0)
return out
else:
return Index(result, name=name)
else:
index = self._orig.index
if expand:
cons = self._orig._constructor_expanddim
result = cons(result, columns=name, index=index, dtype=dtype)
else:
# Must be a Series
cons = self._orig._constructor
result = cons(result, name=name, index=index, dtype=dtype)
return result
def _get_series_list(self, others):
"""
Auxiliary function for :meth:`str.cat`. Turn potentially mixed input
into a list of Series (elements without an index must match the length
of the calling Series/Index).
Parameters
----------
others : Series, DataFrame, np.ndarray, list-like or list-like of
Objects that are either Series, Index or np.ndarray (1-dim).
Returns
-------
list of Series
Others transformed into list of Series.
"""
from pandas import Series, DataFrame
# self._orig is either Series or Index
idx = self._orig if isinstance(self._orig, ABCIndexClass) else self._orig.index
# Generally speaking, all objects without an index inherit the index
# `idx` of the calling Series/Index - i.e. must have matching length.
# Objects with an index (i.e. Series/Index/DataFrame) keep their own.
if isinstance(others, ABCSeries):
return [others]
elif isinstance(others, ABCIndexClass):
return [Series(others.values, index=others)]
elif isinstance(others, ABCDataFrame):
return [others[x] for x in others]
elif isinstance(others, np.ndarray) and others.ndim == 2:
others = DataFrame(others, index=idx)
return [others[x] for x in others]
elif is_list_like(others, allow_sets=False):
others = list(others) # ensure iterators do not get read twice etc
# in case of list-like `others`, all elements must be
# either Series/Index/np.ndarray (1-dim)...
if all(
isinstance(x, (ABCSeries, ABCIndexClass))
or (isinstance(x, np.ndarray) and x.ndim == 1)
for x in others
):
los = []
while others: # iterate through list and append each element
los = los + self._get_series_list(others.pop(0))
return los
# ... or just strings
elif all(not is_list_like(x) for x in others):
return [Series(others, index=idx)]
raise TypeError(
"others must be Series, Index, DataFrame, np.ndarrary "
"or list-like (either containing only strings or "
"containing only objects of type Series/Index/"
"np.ndarray[1-dim])"
)
@forbid_nonstring_types(["bytes", "mixed", "mixed-integer"])
def cat(self, others=None, sep=None, na_rep=None, join="left"):
"""
Concatenate strings in the Series/Index with given separator.
If `others` is specified, this function concatenates the Series/Index
and elements of `others` element-wise.
If `others` is not passed, then all values in the Series/Index are
concatenated into a single string with a given `sep`.
Parameters
----------
others : Series, Index, DataFrame, np.ndarray or list-like
Series, Index, DataFrame, np.ndarray (one- or two-dimensional) and
other list-likes of strings must have the same length as the
calling Series/Index, with the exception of indexed objects (i.e.
Series/Index/DataFrame) if `join` is not None.
If others is a list-like that contains a combination of Series,
Index or np.ndarray (1-dim), then all elements will be unpacked and
must satisfy the above criteria individually.
If others is None, the method returns the concatenation of all
strings in the calling Series/Index.
sep : str, default ''
The separator between the different elements/columns. By default
the empty string `''` is used.
na_rep : str or None, default None
Representation that is inserted for all missing values:
- If `na_rep` is None, and `others` is None, missing values in the
Series/Index are omitted from the result.
- If `na_rep` is None, and `others` is not None, a row containing a
missing value in any of the columns (before concatenation) will
have a missing value in the result.
join : {'left', 'right', 'outer', 'inner'}, default 'left'
Determines the join-style between the calling Series/Index and any
Series/Index/DataFrame in `others` (objects without an index need
to match the length of the calling Series/Index). To disable
alignment, use `.values` on any Series/Index/DataFrame in `others`.
.. versionadded:: 0.23.0
.. versionchanged:: 1.0.0
Changed default of `join` from None to `'left'`.
Returns
-------
str, Series or Index
If `others` is None, `str` is returned, otherwise a `Series/Index`
(same type as caller) of objects is returned.
See Also
--------
split : Split each string in the Series/Index.
join : Join lists contained as elements in the Series/Index.
Examples
--------
When not passing `others`, all values are concatenated into a single
string:
>>> s = pd.Series(['a', 'b', np.nan, 'd'])
>>> s.str.cat(sep=' ')
'a b d'
By default, NA values in the Series are ignored. Using `na_rep`, they
can be given a representation:
>>> s.str.cat(sep=' ', na_rep='?')
'a b ? d'
If `others` is specified, corresponding values are concatenated with
the separator. Result will be a Series of strings.
>>> s.str.cat(['A', 'B', 'C', 'D'], sep=',')
0 a,A
1 b,B
2 NaN
3 d,D
dtype: object
Missing values will remain missing in the result, but can again be
represented using `na_rep`
>>> s.str.cat(['A', 'B', 'C', 'D'], sep=',', na_rep='-')
0 a,A
1 b,B
2 -,C
3 d,D
dtype: object
If `sep` is not specified, the values are concatenated without
separation.
>>> s.str.cat(['A', 'B', 'C', 'D'], na_rep='-')
0 aA
1 bB
2 -C
3 dD
dtype: object
Series with different indexes can be aligned before concatenation. The
`join`-keyword works as in other methods.
>>> t = pd.Series(['d', 'a', 'e', 'c'], index=[3, 0, 4, 2])
>>> s.str.cat(t, join='left', na_rep='-')
0 aa
1 b-
2 -c
3 dd
dtype: object
>>>
>>> s.str.cat(t, join='outer', na_rep='-')
0 aa
1 b-
2 -c
3 dd
4 -e
dtype: object
>>>
>>> s.str.cat(t, join='inner', na_rep='-')
0 aa
2 -c
3 dd
dtype: object
>>>
>>> s.str.cat(t, join='right', na_rep='-')
3 dd
0 aa
4 -e
2 -c
dtype: object
For more examples, see :ref:`here <text.concatenate>`.
"""
from pandas import Index, Series, concat
if isinstance(others, str):
raise ValueError("Did you mean to supply a `sep` keyword?")
if sep is None:
sep = ""
if isinstance(self._orig, ABCIndexClass):
data = Series(self._orig, index=self._orig)
else: # Series
data = self._orig
# concatenate Series/Index with itself if no "others"
if others is None:
data = ensure_object(data)
na_mask = isna(data)
if na_rep is None and na_mask.any():
data = data[~na_mask]
elif na_rep is not None and na_mask.any():
data = np.where(na_mask, na_rep, data)
return sep.join(data)
try:
# turn anything in "others" into lists of Series
others = self._get_series_list(others)
except ValueError: # do not catch TypeError raised by _get_series_list
raise ValueError(
"If `others` contains arrays or lists (or other "
"list-likes without an index), these must all be "
"of the same length as the calling Series/Index."
)
# align if required
if any(not data.index.equals(x.index) for x in others):
# Need to add keys for uniqueness in case of duplicate columns
others = concat(
others,
axis=1,
join=(join if join == "inner" else "outer"),
keys=range(len(others)),
sort=False,
copy=False,
)
data, others = data.align(others, join=join)
others = [others[x] for x in others] # again list of Series
all_cols = [ensure_object(x) for x in [data] + others]
na_masks = np.array([isna(x) for x in all_cols])
union_mask = np.logical_or.reduce(na_masks, axis=0)
if na_rep is None and union_mask.any():
# no na_rep means NaNs for all rows where any column has a NaN
# only necessary if there are actually any NaNs
result = np.empty(len(data), dtype=object)
np.putmask(result, union_mask, np.nan)
not_masked = ~union_mask
result[not_masked] = cat_safe([x[not_masked] for x in all_cols], sep)
elif na_rep is not None and union_mask.any():
# fill NaNs with na_rep in case there are actually any NaNs
all_cols = [
np.where(nm, na_rep, col) for nm, col in zip(na_masks, all_cols)
]
result = cat_safe(all_cols, sep)
else:
# no NaNs - can just concatenate
result = cat_safe(all_cols, sep)
if isinstance(self._orig, ABCIndexClass):
# add dtype for case that result is all-NA
result = Index(result, dtype=object, name=self._orig.name)
else: # Series
if is_categorical_dtype(self._orig.dtype):
# We need to infer the new categories.
dtype = None
else:
dtype = self._orig.dtype
result = Series(result, dtype=dtype, index=data.index, name=self._orig.name)
return result
_shared_docs[
"str_split"
] = r"""
Split strings around given separator/delimiter.
Splits the string in the Series/Index from the %(side)s,
at the specified delimiter string. Equivalent to :meth:`str.%(method)s`.
Parameters
----------
pat : str, optional
String or regular expression to split on.
If not specified, split on whitespace.
n : int, default -1 (all)
Limit number of splits in output.
``None``, 0 and -1 will be interpreted as return all splits.
expand : bool, default False
Expand the splitted strings into separate columns.
* If ``True``, return DataFrame/MultiIndex expanding dimensionality.
* If ``False``, return Series/Index, containing lists of strings.
Returns
-------
Series, Index, DataFrame or MultiIndex
Type matches caller unless ``expand=True`` (see Notes).
See Also
--------
Series.str.split : Split strings around given separator/delimiter.
Series.str.rsplit : Splits string around given separator/delimiter,
starting from the right.
Series.str.join : Join lists contained as elements in the Series/Index
with passed delimiter.
str.split : Standard library version for split.
str.rsplit : Standard library version for rsplit.
Notes
-----
The handling of the `n` keyword depends on the number of found splits:
- If found splits > `n`, make first `n` splits only
- If found splits <= `n`, make all splits
- If for a certain row the number of found splits < `n`,
append `None` for padding up to `n` if ``expand=True``
If using ``expand=True``, Series and Index callers return DataFrame and
MultiIndex objects, respectively.
Examples
--------
>>> s = pd.Series(["this is a regular sentence",
... "https://docs.python.org/3/tutorial/index.html",
... np.nan])
0 this is a regular sentence
1 https://docs.python.org/3/tutorial/index.html
2 NaN
dtype: object
In the default setting, the string is split by whitespace.
>>> s.str.split()
0 [this, is, a, regular, sentence]
1 [https://docs.python.org/3/tutorial/index.html]
2 NaN
dtype: object
Without the `n` parameter, the outputs of `rsplit` and `split`
are identical.
>>> s.str.rsplit()
0 [this, is, a, regular, sentence]
1 [https://docs.python.org/3/tutorial/index.html]
2 NaN
dtype: object
The `n` parameter can be used to limit the number of splits on the
delimiter. The outputs of `split` and `rsplit` are different.
>>> s.str.split(n=2)
0 [this, is, a regular sentence]
1 [https://docs.python.org/3/tutorial/index.html]
2 NaN
dtype: object
>>> s.str.rsplit(n=2)
0 [this is a, regular, sentence]
1 [https://docs.python.org/3/tutorial/index.html]
2 NaN
dtype: object
The `pat` parameter can be used to split by other characters.
>>> s.str.split(pat = "/")
0 [this is a regular sentence]
1 [https:, , docs.python.org, 3, tutorial, index...
2 NaN
dtype: object
When using ``expand=True``, the split elements will expand out into
separate columns. If NaN is present, it is propagated throughout
the columns during the split.
>>> s.str.split(expand=True)
0 1 2 3
0 this is a regular
1 https://docs.python.org/3/tutorial/index.html None None None
2 NaN NaN NaN NaN \
4
0 sentence
1 None
2 NaN
For slightly more complex use cases like splitting the html document name
from a url, a combination of parameter settings can be used.
>>> s.str.rsplit("/", n=1, expand=True)
0 1
0 this is a regular sentence None
1 https://docs.python.org/3/tutorial index.html
2 NaN NaN
Remember to escape special characters when explicitly using regular
expressions.
>>> s = pd.Series(["1+1=2"])
>>> s.str.split(r"\+|=", expand=True)
0 1 2
0 1 1 2
"""
@Appender(_shared_docs["str_split"] % {"side": "beginning", "method": "split"})
@forbid_nonstring_types(["bytes"])
def split(self, pat=None, n=-1, expand=False):
result = str_split(self._parent, pat, n=n)
return self._wrap_result(result, expand=expand, returns_string=expand)
@Appender(_shared_docs["str_split"] % {"side": "end", "method": "rsplit"})
@forbid_nonstring_types(["bytes"])
def rsplit(self, pat=None, n=-1, expand=False):
result = str_rsplit(self._parent, pat, n=n)
return self._wrap_result(result, expand=expand, returns_string=expand)
_shared_docs[
"str_partition"
] = """
Split the string at the %(side)s occurrence of `sep`.
This method splits the string at the %(side)s occurrence of `sep`,
and returns 3 elements containing the part before the separator,
the separator itself, and the part after the separator.
If the separator is not found, return %(return)s.
Parameters
----------
sep : str, default whitespace
String to split on.
pat : str, default whitespace
.. deprecated:: 0.24.0
Use ``sep`` instead.
expand : bool, default True
If True, return DataFrame/MultiIndex expanding dimensionality.
If False, return Series/Index.
Returns
-------
DataFrame/MultiIndex or Series/Index of objects
See Also
--------
%(also)s
Series.str.split : Split strings around given separators.
str.partition : Standard library version.
Examples
--------
>>> s = pd.Series(['Linda van der Berg', 'George Pitt-Rivers'])
>>> s
0 Linda van der Berg
1 George Pitt-Rivers
dtype: object
>>> s.str.partition()
0 1 2
0 Linda van der Berg
1 George Pitt-Rivers
To partition by the last space instead of the first one:
>>> s.str.rpartition()
0 1 2
0 Linda van der Berg
1 George Pitt-Rivers
To partition by something different than a space:
>>> s.str.partition('-')
0 1 2
0 Linda van der Berg
1 George Pitt - Rivers
To return a Series containing tuples instead of a DataFrame:
>>> s.str.partition('-', expand=False)
0 (Linda van der Berg, , )
1 (George Pitt, -, Rivers)
dtype: object
Also available on indices:
>>> idx = pd.Index(['X 123', 'Y 999'])
>>> idx
Index(['X 123', 'Y 999'], dtype='object')
Which will create a MultiIndex:
>>> idx.str.partition()
MultiIndex([('X', ' ', '123'),
('Y', ' ', '999')],
dtype='object')
Or an index with tuples with ``expand=False``:
>>> idx.str.partition(expand=False)
Index([('X', ' ', '123'), ('Y', ' ', '999')], dtype='object')
"""
@Appender(
_shared_docs["str_partition"]
% {
"side": "first",
"return": "3 elements containing the string itself, followed by two "
"empty strings",
"also": "rpartition : Split the string at the last occurrence of `sep`.",
}
)
@deprecate_kwarg(old_arg_name="pat", new_arg_name="sep")
@forbid_nonstring_types(["bytes"])
def partition(self, sep=" ", expand=True):
f = lambda x: x.partition(sep)
result = _na_map(f, self._parent)
return self._wrap_result(result, expand=expand, returns_string=expand)
@Appender(
_shared_docs["str_partition"]
% {
"side": "last",
"return": "3 elements containing two empty strings, followed by the "
"string itself",
"also": "partition : Split the string at the first occurrence of `sep`.",
}
)
@deprecate_kwarg(old_arg_name="pat", new_arg_name="sep")
@forbid_nonstring_types(["bytes"])
def rpartition(self, sep=" ", expand=True):
f = lambda x: x.rpartition(sep)
result = _na_map(f, self._parent)
return self._wrap_result(result, expand=expand, returns_string=expand)
@copy(str_get)
def get(self, i):
result = str_get(self._parent, i)
return self._wrap_result(result)
@copy(str_join)
@forbid_nonstring_types(["bytes"])
def join(self, sep):
result = str_join(self._parent, sep)
return self._wrap_result(result)
@copy(str_contains)
@forbid_nonstring_types(["bytes"])
def contains(self, pat, case=True, flags=0, na=np.nan, regex=True):
result = str_contains(
self._parent, pat, case=case, flags=flags, na=na, regex=regex
)
return self._wrap_result(result, fill_value=na, returns_string=False)
@copy(str_match)
@forbid_nonstring_types(["bytes"])
def match(self, pat, case=True, flags=0, na=np.nan):
result = str_match(self._parent, pat, case=case, flags=flags, na=na)
return self._wrap_result(result, fill_value=na, returns_string=False)
@copy(str_replace)
@forbid_nonstring_types(["bytes"])
def replace(self, pat, repl, n=-1, case=None, flags=0, regex=True):
result = str_replace(
self._parent, pat, repl, n=n, case=case, flags=flags, regex=regex
)
return self._wrap_result(result)
@copy(str_repeat)
@forbid_nonstring_types(["bytes"])
def repeat(self, repeats):
result = str_repeat(self._parent, repeats)
return self._wrap_result(result)
@copy(str_pad)
@forbid_nonstring_types(["bytes"])
def pad(self, width, side="left", fillchar=" "):
result = str_pad(self._parent, width, side=side, fillchar=fillchar)
return self._wrap_result(result)
_shared_docs[
"str_pad"
] = """
Filling %(side)s side of strings in the Series/Index with an
additional character. Equivalent to :meth:`str.%(method)s`.
Parameters
----------
width : int
Minimum width of resulting string; additional characters will be filled
with ``fillchar``.
fillchar : str
Additional character for filling, default is whitespace.
Returns
-------
filled : Series/Index of objects.
"""
@Appender(_shared_docs["str_pad"] % dict(side="left and right", method="center"))
@forbid_nonstring_types(["bytes"])
def center(self, width, fillchar=" "):
return self.pad(width, side="both", fillchar=fillchar)
@Appender(_shared_docs["str_pad"] % dict(side="right", method="ljust"))
@forbid_nonstring_types(["bytes"])
def ljust(self, width, fillchar=" "):
return self.pad(width, side="right", fillchar=fillchar)
@Appender(_shared_docs["str_pad"] % dict(side="left", method="rjust"))
@forbid_nonstring_types(["bytes"])
def rjust(self, width, fillchar=" "):
return self.pad(width, side="left", fillchar=fillchar)
@forbid_nonstring_types(["bytes"])
def zfill(self, width):
"""
Pad strings in the Series/Index by prepending '0' characters.
Strings in the Series/Index are padded with '0' characters on the
left of the string to reach a total string length `width`. Strings
in the Series/Index with length greater or equal to `width` are
unchanged.
Parameters
----------
width : int
Minimum length of resulting string; strings with length less
than `width` be prepended with '0' characters.
Returns
-------
Series/Index of objects.
See Also
--------
Series.str.rjust : Fills the left side of strings with an arbitrary
character.
Series.str.ljust : Fills the right side of strings with an arbitrary
character.
Series.str.pad : Fills the specified sides of strings with an arbitrary
character.
Series.str.center : Fills boths sides of strings with an arbitrary
character.
Notes
-----
Differs from :meth:`str.zfill` which has special handling
for '+'/'-' in the string.
Examples
--------
>>> s = pd.Series(['-1', '1', '1000', 10, np.nan])
>>> s
0 -1
1 1
2 1000
3 10
4 NaN
dtype: object
Note that ``10`` and ``NaN`` are not strings, therefore they are
converted to ``NaN``. The minus sign in ``'-1'`` is treated as a
regular character and the zero is added to the left of it
(:meth:`str.zfill` would have moved it to the left). ``1000``
remains unchanged as it is longer than `width`.
>>> s.str.zfill(3)
0 0-1
1 001
2 1000
3 NaN
4 NaN
dtype: object
"""
result = str_pad(self._parent, width, side="left", fillchar="0")
return self._wrap_result(result)
@copy(str_slice)
def slice(self, start=None, stop=None, step=None):
result = str_slice(self._parent, start, stop, step)
return self._wrap_result(result)
@copy(str_slice_replace)
@forbid_nonstring_types(["bytes"])
def slice_replace(self, start=None, stop=None, repl=None):
result = str_slice_replace(self._parent, start, stop, repl)
return self._wrap_result(result)
@copy(str_decode)
def decode(self, encoding, errors="strict"):
# need to allow bytes here
result = str_decode(self._parent, encoding, errors)
# TODO: Not sure how to handle this.
return self._wrap_result(result, returns_string=False)
@copy(str_encode)
@forbid_nonstring_types(["bytes"])
def encode(self, encoding, errors="strict"):
result = str_encode(self._parent, encoding, errors)
return self._wrap_result(result, returns_string=False)
_shared_docs[
"str_strip"
] = r"""
Remove leading and trailing characters.
Strip whitespaces (including newlines) or a set of specified characters
from each string in the Series/Index from %(side)s.
Equivalent to :meth:`str.%(method)s`.
Parameters
----------
to_strip : str or None, default None
Specifying the set of characters to be removed.
All combinations of this set of characters will be stripped.
If None then whitespaces are removed.
Returns
-------
Series or Index of object
See Also
--------
Series.str.strip : Remove leading and trailing characters in Series/Index.
Series.str.lstrip : Remove leading characters in Series/Index.
Series.str.rstrip : Remove trailing characters in Series/Index.
Examples
--------
>>> s = pd.Series(['1. Ant. ', '2. Bee!\n', '3. Cat?\t', np.nan])
>>> s
0 1. Ant.
1 2. Bee!\n
2 3. Cat?\t
3 NaN
dtype: object
>>> s.str.strip()
0 1. Ant.
1 2. Bee!
2 3. Cat?
3 NaN
dtype: object
>>> s.str.lstrip('123.')
0 Ant.
1 Bee!\n
2 Cat?\t
3 NaN
dtype: object
>>> s.str.rstrip('.!? \n\t')
0 1. Ant
1 2. Bee
2 3. Cat
3 NaN
dtype: object
>>> s.str.strip('123.!? \n\t')
0 Ant
1 Bee
2 Cat
3 NaN
dtype: object
"""
@Appender(
_shared_docs["str_strip"] % dict(side="left and right sides", method="strip")
)
@forbid_nonstring_types(["bytes"])
def strip(self, to_strip=None):
result = str_strip(self._parent, to_strip, side="both")
return self._wrap_result(result)
@Appender(_shared_docs["str_strip"] % dict(side="left side", method="lstrip"))
@forbid_nonstring_types(["bytes"])
def lstrip(self, to_strip=None):
result = str_strip(self._parent, to_strip, side="left")
return self._wrap_result(result)
@Appender(_shared_docs["str_strip"] % dict(side="right side", method="rstrip"))
@forbid_nonstring_types(["bytes"])
def rstrip(self, to_strip=None):
result = str_strip(self._parent, to_strip, side="right")
return self._wrap_result(result)
@copy(str_wrap)
@forbid_nonstring_types(["bytes"])
def wrap(self, width, **kwargs):
result = str_wrap(self._parent, width, **kwargs)
return self._wrap_result(result)
@copy(str_get_dummies)
@forbid_nonstring_types(["bytes"])
def get_dummies(self, sep="|"):
# we need to cast to Series of strings as only that has all
# methods available for making the dummies...
data = self._orig.astype(str) if self._is_categorical else self._parent
result, name = str_get_dummies(data, sep)
return self._wrap_result(
result,
use_codes=(not self._is_categorical),
name=name,
expand=True,
returns_string=False,
)
@copy(str_translate)
@forbid_nonstring_types(["bytes"])
def translate(self, table):
result = str_translate(self._parent, table)
return self._wrap_result(result)
count = _pat_wrapper(str_count, flags=True, name="count", returns_string=False)
startswith = _pat_wrapper(
str_startswith, na=True, name="startswith", returns_string=False
)
endswith = _pat_wrapper(
str_endswith, na=True, name="endswith", returns_string=False
)
findall = _pat_wrapper(
str_findall, flags=True, name="findall", returns_string=False
)
@copy(str_extract)
@forbid_nonstring_types(["bytes"])
def extract(self, pat, flags=0, expand=True):
return str_extract(self, pat, flags=flags, expand=expand)
@copy(str_extractall)
@forbid_nonstring_types(["bytes"])
def extractall(self, pat, flags=0):
return str_extractall(self._orig, pat, flags=flags)
_shared_docs[
"find"
] = """
Return %(side)s indexes in each strings in the Series/Index
where the substring is fully contained between [start:end].
Return -1 on failure. Equivalent to standard :meth:`str.%(method)s`.
Parameters
----------
sub : str
Substring being searched.
start : int
Left edge index.
end : int
Right edge index.
Returns
-------
Series or Index of int.
See Also
--------
%(also)s
"""
@Appender(
_shared_docs["find"]
% dict(
side="lowest",
method="find",
also="rfind : Return highest indexes in each strings.",
)
)
@forbid_nonstring_types(["bytes"])
def find(self, sub, start=0, end=None):
result = str_find(self._parent, sub, start=start, end=end, side="left")
return self._wrap_result(result, returns_string=False)
@Appender(
_shared_docs["find"]
% dict(
side="highest",
method="rfind",
also="find : Return lowest indexes in each strings.",
)
)
@forbid_nonstring_types(["bytes"])
def rfind(self, sub, start=0, end=None):
result = str_find(self._parent, sub, start=start, end=end, side="right")
return self._wrap_result(result, returns_string=False)
@forbid_nonstring_types(["bytes"])
def normalize(self, form):
"""
Return the Unicode normal form for the strings in the Series/Index.
For more information on the forms, see the
:func:`unicodedata.normalize`.
Parameters
----------
form : {'NFC', 'NFKC', 'NFD', 'NFKD'}
Unicode form.
Returns
-------
normalized : Series/Index of objects
"""
import unicodedata
f = lambda x: unicodedata.normalize(form, x)
result = _na_map(f, self._parent)
return self._wrap_result(result)
_shared_docs[
"index"
] = """
Return %(side)s indexes in each strings where the substring is
fully contained between [start:end]. This is the same as
``str.%(similar)s`` except instead of returning -1, it raises a ValueError
when the substring is not found. Equivalent to standard ``str.%(method)s``.
Parameters
----------
sub : str
Substring being searched.
start : int
Left edge index.
end : int
Right edge index.
Returns
-------
Series or Index of object
See Also
--------
%(also)s
"""
@Appender(
_shared_docs["index"]
% dict(
side="lowest",
similar="find",
method="index",
also="rindex : Return highest indexes in each strings.",
)
)
@forbid_nonstring_types(["bytes"])
def index(self, sub, start=0, end=None):
result = str_index(self._parent, sub, start=start, end=end, side="left")
return self._wrap_result(result, returns_string=False)
@Appender(
_shared_docs["index"]
% dict(
side="highest",
similar="rfind",
method="rindex",
also="index : Return lowest indexes in each strings.",
)
)
@forbid_nonstring_types(["bytes"])
def rindex(self, sub, start=0, end=None):
result = str_index(self._parent, sub, start=start, end=end, side="right")
return self._wrap_result(result, returns_string=False)
_shared_docs[
"len"
] = """
Compute the length of each element in the Series/Index. The element may be
a sequence (such as a string, tuple or list) or a collection
(such as a dictionary).
Returns
-------
Series or Index of int
A Series or Index of integer values indicating the length of each
element in the Series or Index.
See Also
--------
str.len : Python built-in function returning the length of an object.
Series.size : Returns the length of the Series.
Examples
--------
Returns the length (number of characters) in a string. Returns the
number of entries for dictionaries, lists or tuples.
>>> s = pd.Series(['dog',
... '',
... 5,
... {'foo' : 'bar'},
... [2, 3, 5, 7],
... ('one', 'two', 'three')])
>>> s
0 dog
1
2 5
3 {'foo': 'bar'}
4 [2, 3, 5, 7]
5 (one, two, three)
dtype: object
>>> s.str.len()
0 3.0
1 0.0
2 NaN
3 1.0
4 4.0
5 3.0
dtype: float64
"""
len = _noarg_wrapper(
len,
docstring=_shared_docs["len"],
forbidden_types=None,
dtype=int,
returns_string=False,
)
_shared_docs[
"casemethods"
] = """
Convert strings in the Series/Index to %(type)s.
%(version)s
Equivalent to :meth:`str.%(method)s`.
Returns
-------
Series or Index of object
See Also
--------
Series.str.lower : Converts all characters to lowercase.
Series.str.upper : Converts all characters to uppercase.
Series.str.title : Converts first character of each word to uppercase and
remaining to lowercase.
Series.str.capitalize : Converts first character to uppercase and
remaining to lowercase.
Series.str.swapcase : Converts uppercase to lowercase and lowercase to
uppercase.
Series.str.casefold: Removes all case distinctions in the string.
Examples
--------
>>> s = pd.Series(['lower', 'CAPITALS', 'this is a sentence', 'SwApCaSe'])
>>> s
0 lower
1 CAPITALS
2 this is a sentence
3 SwApCaSe
dtype: object
>>> s.str.lower()
0 lower
1 capitals
2 this is a sentence
3 swapcase
dtype: object
>>> s.str.upper()
0 LOWER
1 CAPITALS
2 THIS IS A SENTENCE
3 SWAPCASE
dtype: object
>>> s.str.title()
0 Lower
1 Capitals
2 This Is A Sentence
3 Swapcase
dtype: object
>>> s.str.capitalize()
0 Lower
1 Capitals
2 This is a sentence
3 Swapcase
dtype: object
>>> s.str.swapcase()
0 LOWER
1 capitals
2 THIS IS A SENTENCE
3 sWaPcAsE
dtype: object
"""
# _doc_args holds dict of strings to use in substituting casemethod docs
_doc_args = {} # type: Dict[str, Dict[str, str]]
_doc_args["lower"] = dict(type="lowercase", method="lower", version="")
_doc_args["upper"] = dict(type="uppercase", method="upper", version="")
_doc_args["title"] = dict(type="titlecase", method="title", version="")
_doc_args["capitalize"] = dict(
type="be capitalized", method="capitalize", version=""
)
_doc_args["swapcase"] = dict(type="be swapcased", method="swapcase", version="")
_doc_args["casefold"] = dict(
type="be casefolded",
method="casefold",
version="\n .. versionadded:: 0.25.0\n",
)
lower = _noarg_wrapper(
lambda x: x.lower(),
name="lower",
docstring=_shared_docs["casemethods"] % _doc_args["lower"],
)
upper = _noarg_wrapper(
lambda x: x.upper(),
name="upper",
docstring=_shared_docs["casemethods"] % _doc_args["upper"],
)
title = _noarg_wrapper(
lambda x: x.title(),
name="title",
docstring=_shared_docs["casemethods"] % _doc_args["title"],
)
capitalize = _noarg_wrapper(
lambda x: x.capitalize(),
name="capitalize",
docstring=_shared_docs["casemethods"] % _doc_args["capitalize"],
)
swapcase = _noarg_wrapper(
lambda x: x.swapcase(),
name="swapcase",
docstring=_shared_docs["casemethods"] % _doc_args["swapcase"],
)
casefold = _noarg_wrapper(
lambda x: x.casefold(),
name="casefold",
docstring=_shared_docs["casemethods"] % _doc_args["casefold"],
)
_shared_docs[
"ismethods"
] = """
Check whether all characters in each string are %(type)s.
This is equivalent to running the Python string method
:meth:`str.%(method)s` for each element of the Series/Index. If a string
has zero characters, ``False`` is returned for that check.
Returns
-------
Series or Index of bool
Series or Index of boolean values with the same length as the original
Series/Index.
See Also
--------
Series.str.isalpha : Check whether all characters are alphabetic.
Series.str.isnumeric : Check whether all characters are numeric.
Series.str.isalnum : Check whether all characters are alphanumeric.
Series.str.isdigit : Check whether all characters are digits.
Series.str.isdecimal : Check whether all characters are decimal.
Series.str.isspace : Check whether all characters are whitespace.
Series.str.islower : Check whether all characters are lowercase.
Series.str.isupper : Check whether all characters are uppercase.
Series.str.istitle : Check whether all characters are titlecase.
Examples
--------
**Checks for Alphabetic and Numeric Characters**
>>> s1 = pd.Series(['one', 'one1', '1', ''])
>>> s1.str.isalpha()
0 True
1 False
2 False
3 False
dtype: bool
>>> s1.str.isnumeric()
0 False
1 False
2 True
3 False
dtype: bool
>>> s1.str.isalnum()
0 True
1 True
2 True
3 False
dtype: bool
Note that checks against characters mixed with any additional punctuation
or whitespace will evaluate to false for an alphanumeric check.
>>> s2 = pd.Series(['A B', '1.5', '3,000'])
>>> s2.str.isalnum()
0 False
1 False
2 False
dtype: bool
**More Detailed Checks for Numeric Characters**
There are several different but overlapping sets of numeric characters that
can be checked for.
>>> s3 = pd.Series(['23', '³', '⅕', ''])
The ``s3.str.isdecimal`` method checks for characters used to form numbers
in base 10.
>>> s3.str.isdecimal()
0 True
1 False
2 False
3 False
dtype: bool
The ``s.str.isdigit`` method is the same as ``s3.str.isdecimal`` but also
includes special digits, like superscripted and subscripted digits in
unicode.
>>> s3.str.isdigit()
0 True
1 True
2 False
3 False
dtype: bool
The ``s.str.isnumeric`` method is the same as ``s3.str.isdigit`` but also
includes other characters that can represent quantities such as unicode
fractions.
>>> s3.str.isnumeric()
0 True
1 True
2 True
3 False
dtype: bool
**Checks for Whitespace**
>>> s4 = pd.Series([' ', '\\t\\r\\n ', ''])
>>> s4.str.isspace()
0 True
1 True
2 False
dtype: bool
**Checks for Character Case**
>>> s5 = pd.Series(['leopard', 'Golden Eagle', 'SNAKE', ''])
>>> s5.str.islower()
0 True
1 False
2 False
3 False
dtype: bool
>>> s5.str.isupper()
0 False
1 False
2 True
3 False
dtype: bool
The ``s5.str.istitle`` method checks for whether all words are in title
case (whether only the first letter of each word is capitalized). Words are
assumed to be as any sequence of non-numeric characters separated by
whitespace characters.
>>> s5.str.istitle()
0 False
1 True
2 False
3 False
dtype: bool
"""
_doc_args["isalnum"] = dict(type="alphanumeric", method="isalnum")
_doc_args["isalpha"] = dict(type="alphabetic", method="isalpha")
_doc_args["isdigit"] = dict(type="digits", method="isdigit")
_doc_args["isspace"] = dict(type="whitespace", method="isspace")
_doc_args["islower"] = dict(type="lowercase", method="islower")
_doc_args["isupper"] = dict(type="uppercase", method="isupper")
_doc_args["istitle"] = dict(type="titlecase", method="istitle")
_doc_args["isnumeric"] = dict(type="numeric", method="isnumeric")
_doc_args["isdecimal"] = dict(type="decimal", method="isdecimal")
# force _noarg_wrapper return type with dtype=bool (GH 29624)
isalnum = _noarg_wrapper(
lambda x: x.isalnum(),
name="isalnum",
docstring=_shared_docs["ismethods"] % _doc_args["isalnum"],
returns_string=False,
dtype=bool,
)
isalpha = _noarg_wrapper(
lambda x: x.isalpha(),
name="isalpha",
docstring=_shared_docs["ismethods"] % _doc_args["isalpha"],
returns_string=False,
dtype=bool,
)
isdigit = _noarg_wrapper(
lambda x: x.isdigit(),
name="isdigit",
docstring=_shared_docs["ismethods"] % _doc_args["isdigit"],
returns_string=False,
dtype=bool,
)
isspace = _noarg_wrapper(
lambda x: x.isspace(),
name="isspace",
docstring=_shared_docs["ismethods"] % _doc_args["isspace"],
returns_string=False,
dtype=bool,
)
islower = _noarg_wrapper(
lambda x: x.islower(),
name="islower",
docstring=_shared_docs["ismethods"] % _doc_args["islower"],
returns_string=False,
dtype=bool,
)
isupper = _noarg_wrapper(
lambda x: x.isupper(),
name="isupper",
docstring=_shared_docs["ismethods"] % _doc_args["isupper"],
returns_string=False,
dtype=bool,
)
istitle = _noarg_wrapper(
lambda x: x.istitle(),
name="istitle",
docstring=_shared_docs["ismethods"] % _doc_args["istitle"],
returns_string=False,
dtype=bool,
)
isnumeric = _noarg_wrapper(
lambda x: x.isnumeric(),
name="isnumeric",
docstring=_shared_docs["ismethods"] % _doc_args["isnumeric"],
returns_string=False,
dtype=bool,
)
isdecimal = _noarg_wrapper(
lambda x: x.isdecimal(),
name="isdecimal",
docstring=_shared_docs["ismethods"] % _doc_args["isdecimal"],
returns_string=False,
dtype=bool,
)
@classmethod
def _make_accessor(cls, data):
cls._validate(data)
return cls(data)
| BugsInPy/BugsInPy/temp/projects/pandas/bug-124-fixed/pandas/pandas/core/strings.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-124-buggy/pandas/pandas/core/strings.py |
pandas-bug-136 | """
SQL-style merge routines
"""
import copy
import datetime
from functools import partial
import string
import warnings
import numpy as np
from pandas._libs import hashtable as libhashtable, lib
import pandas._libs.join as libjoin
from pandas.errors import MergeError
from pandas.util._decorators import Appender, Substitution
from pandas.core.dtypes.common import (
ensure_float64,
ensure_int64,
ensure_object,
is_array_like,
is_bool,
is_bool_dtype,
is_categorical_dtype,
is_datetime64tz_dtype,
is_datetimelike,
is_dtype_equal,
is_extension_array_dtype,
is_float_dtype,
is_int64_dtype,
is_integer,
is_integer_dtype,
is_list_like,
is_number,
is_numeric_dtype,
is_object_dtype,
needs_i8_conversion,
)
from pandas.core.dtypes.missing import isnull, na_value_for_dtype
from pandas import Categorical, DataFrame, Index, MultiIndex, Series, Timedelta
import pandas.core.algorithms as algos
from pandas.core.arrays.categorical import _recode_for_categories
import pandas.core.common as com
from pandas.core.frame import _merge_doc
from pandas.core.internals import _transform_index, concatenate_block_managers
import pandas.core.sorting as sorting
from pandas.core.sorting import is_int64_overflow_possible
@Substitution("\nleft : DataFrame")
@Appender(_merge_doc, indents=0)
def merge(
left,
right,
how="inner",
on=None,
left_on=None,
right_on=None,
left_index=False,
right_index=False,
sort=False,
suffixes=("_x", "_y"),
copy=True,
indicator=False,
validate=None,
):
op = _MergeOperation(
left,
right,
how=how,
on=on,
left_on=left_on,
right_on=right_on,
left_index=left_index,
right_index=right_index,
sort=sort,
suffixes=suffixes,
copy=copy,
indicator=indicator,
validate=validate,
)
return op.get_result()
if __debug__:
merge.__doc__ = _merge_doc % "\nleft : DataFrame"
def _groupby_and_merge(by, on, left, right, _merge_pieces, check_duplicates=True):
"""
groupby & merge; we are always performing a left-by type operation
Parameters
----------
by: field to group
on: duplicates field
left: left frame
right: right frame
_merge_pieces: function for merging
check_duplicates: bool, default True
should we check & clean duplicates
"""
pieces = []
if not isinstance(by, (list, tuple)):
by = [by]
lby = left.groupby(by, sort=False)
# if we can groupby the rhs
# then we can get vastly better perf
try:
# we will check & remove duplicates if indicated
if check_duplicates:
if on is None:
on = []
elif not isinstance(on, (list, tuple)):
on = [on]
if right.duplicated(by + on).any():
right = right.drop_duplicates(by + on, keep="last")
rby = right.groupby(by, sort=False)
except KeyError:
rby = None
for key, lhs in lby:
if rby is None:
rhs = right
else:
try:
rhs = right.take(rby.indices[key])
except KeyError:
# key doesn't exist in left
lcols = lhs.columns.tolist()
cols = lcols + [r for r in right.columns if r not in set(lcols)]
merged = lhs.reindex(columns=cols)
merged.index = range(len(merged))
pieces.append(merged)
continue
merged = _merge_pieces(lhs, rhs)
# make sure join keys are in the merged
# TODO, should _merge_pieces do this?
for k in by:
try:
if k in merged:
merged[k] = key
except KeyError:
pass
pieces.append(merged)
# preserve the original order
# if we have a missing piece this can be reset
from pandas.core.reshape.concat import concat
result = concat(pieces, ignore_index=True)
result = result.reindex(columns=pieces[0].columns, copy=False)
return result, lby
def merge_ordered(
left,
right,
on=None,
left_on=None,
right_on=None,
left_by=None,
right_by=None,
fill_method=None,
suffixes=("_x", "_y"),
how="outer",
):
"""
Perform merge with optional filling/interpolation designed for ordered
data like time series data. Optionally perform group-wise merge (see
examples).
Parameters
----------
left : DataFrame
right : DataFrame
on : label or list
Field names to join on. Must be found in both DataFrames.
left_on : label or list, or array-like
Field names to join on in left DataFrame. Can be a vector or list of
vectors of the length of the DataFrame to use a particular vector as
the join key instead of columns
right_on : label or list, or array-like
Field names to join on in right DataFrame or vector/list of vectors per
left_on docs
left_by : column name or list of column names
Group left DataFrame by group columns and merge piece by piece with
right DataFrame
right_by : column name or list of column names
Group right DataFrame by group columns and merge piece by piece with
left DataFrame
fill_method : {'ffill', None}, default None
Interpolation method for data
suffixes : Sequence, default is ("_x", "_y")
A length-2 sequence where each element is optionally a string
indicating the suffix to add to overlapping column names in
`left` and `right` respectively. Pass a value of `None` instead
of a string to indicate that the column name from `left` or
`right` should be left as-is, with no suffix. At least one of the
values must not be None.
.. versionchanged:: 0.25.0
how : {'left', 'right', 'outer', 'inner'}, default 'outer'
* left: use only keys from left frame (SQL: left outer join)
* right: use only keys from right frame (SQL: right outer join)
* outer: use union of keys from both frames (SQL: full outer join)
* inner: use intersection of keys from both frames (SQL: inner join)
Returns
-------
merged : DataFrame
The output type will the be same as 'left', if it is a subclass
of DataFrame.
See Also
--------
merge
merge_asof
Examples
--------
>>> A >>> B
key lvalue group key rvalue
0 a 1 a 0 b 1
1 c 2 a 1 c 2
2 e 3 a 2 d 3
3 a 1 b
4 c 2 b
5 e 3 b
>>> merge_ordered(A, B, fill_method='ffill', left_by='group')
group key lvalue rvalue
0 a a 1 NaN
1 a b 1 1.0
2 a c 2 2.0
3 a d 2 3.0
4 a e 3 3.0
5 b a 1 NaN
6 b b 1 1.0
7 b c 2 2.0
8 b d 2 3.0
9 b e 3 3.0
"""
def _merger(x, y):
# perform the ordered merge operation
op = _OrderedMerge(
x,
y,
on=on,
left_on=left_on,
right_on=right_on,
suffixes=suffixes,
fill_method=fill_method,
how=how,
)
return op.get_result()
if left_by is not None and right_by is not None:
raise ValueError("Can only group either left or right frames")
elif left_by is not None:
result, _ = _groupby_and_merge(
left_by, on, left, right, lambda x, y: _merger(x, y), check_duplicates=False
)
elif right_by is not None:
result, _ = _groupby_and_merge(
right_by,
on,
right,
left,
lambda x, y: _merger(y, x),
check_duplicates=False,
)
else:
result = _merger(left, right)
return result
def merge_asof(
left,
right,
on=None,
left_on=None,
right_on=None,
left_index=False,
right_index=False,
by=None,
left_by=None,
right_by=None,
suffixes=("_x", "_y"),
tolerance=None,
allow_exact_matches=True,
direction="backward",
):
"""
Perform an asof merge. This is similar to a left-join except that we
match on nearest key rather than equal keys.
Both DataFrames must be sorted by the key.
For each row in the left DataFrame:
- A "backward" search selects the last row in the right DataFrame whose
'on' key is less than or equal to the left's key.
- A "forward" search selects the first row in the right DataFrame whose
'on' key is greater than or equal to the left's key.
- A "nearest" search selects the row in the right DataFrame whose 'on'
key is closest in absolute distance to the left's key.
The default is "backward" and is compatible in versions below 0.20.0.
The direction parameter was added in version 0.20.0 and introduces
"forward" and "nearest".
Optionally match on equivalent keys with 'by' before searching with 'on'.
Parameters
----------
left : DataFrame
right : DataFrame
on : label
Field name to join on. Must be found in both DataFrames.
The data MUST be ordered. Furthermore this must be a numeric column,
such as datetimelike, integer, or float. On or left_on/right_on
must be given.
left_on : label
Field name to join on in left DataFrame.
right_on : label
Field name to join on in right DataFrame.
left_index : bool
Use the index of the left DataFrame as the join key.
right_index : bool
Use the index of the right DataFrame as the join key.
by : column name or list of column names
Match on these columns before performing merge operation.
left_by : column name
Field names to match on in the left DataFrame.
right_by : column name
Field names to match on in the right DataFrame.
suffixes : 2-length sequence (tuple, list, ...)
Suffix to apply to overlapping column names in the left and right
side, respectively.
tolerance : int or Timedelta, optional, default None
Select asof tolerance within this range; must be compatible
with the merge index.
allow_exact_matches : bool, default True
- If True, allow matching with the same 'on' value
(i.e. less-than-or-equal-to / greater-than-or-equal-to)
- If False, don't match the same 'on' value
(i.e., strictly less-than / strictly greater-than)
direction : 'backward' (default), 'forward', or 'nearest'
Whether to search for prior, subsequent, or closest matches.
.. versionadded:: 0.20.0
Returns
-------
merged : DataFrame
See Also
--------
merge
merge_ordered
Examples
--------
>>> left = pd.DataFrame({'a': [1, 5, 10], 'left_val': ['a', 'b', 'c']})
>>> left
a left_val
0 1 a
1 5 b
2 10 c
>>> right = pd.DataFrame({'a': [1, 2, 3, 6, 7],
... 'right_val': [1, 2, 3, 6, 7]})
>>> right
a right_val
0 1 1
1 2 2
2 3 3
3 6 6
4 7 7
>>> pd.merge_asof(left, right, on='a')
a left_val right_val
0 1 a 1
1 5 b 3
2 10 c 7
>>> pd.merge_asof(left, right, on='a', allow_exact_matches=False)
a left_val right_val
0 1 a NaN
1 5 b 3.0
2 10 c 7.0
>>> pd.merge_asof(left, right, on='a', direction='forward')
a left_val right_val
0 1 a 1.0
1 5 b 6.0
2 10 c NaN
>>> pd.merge_asof(left, right, on='a', direction='nearest')
a left_val right_val
0 1 a 1
1 5 b 6
2 10 c 7
We can use indexed DataFrames as well.
>>> left = pd.DataFrame({'left_val': ['a', 'b', 'c']}, index=[1, 5, 10])
>>> left
left_val
1 a
5 b
10 c
>>> right = pd.DataFrame({'right_val': [1, 2, 3, 6, 7]},
... index=[1, 2, 3, 6, 7])
>>> right
right_val
1 1
2 2
3 3
6 6
7 7
>>> pd.merge_asof(left, right, left_index=True, right_index=True)
left_val right_val
1 a 1
5 b 3
10 c 7
Here is a real-world times-series example
>>> quotes
time ticker bid ask
0 2016-05-25 13:30:00.023 GOOG 720.50 720.93
1 2016-05-25 13:30:00.023 MSFT 51.95 51.96
2 2016-05-25 13:30:00.030 MSFT 51.97 51.98
3 2016-05-25 13:30:00.041 MSFT 51.99 52.00
4 2016-05-25 13:30:00.048 GOOG 720.50 720.93
5 2016-05-25 13:30:00.049 AAPL 97.99 98.01
6 2016-05-25 13:30:00.072 GOOG 720.50 720.88
7 2016-05-25 13:30:00.075 MSFT 52.01 52.03
>>> trades
time ticker price quantity
0 2016-05-25 13:30:00.023 MSFT 51.95 75
1 2016-05-25 13:30:00.038 MSFT 51.95 155
2 2016-05-25 13:30:00.048 GOOG 720.77 100
3 2016-05-25 13:30:00.048 GOOG 720.92 100
4 2016-05-25 13:30:00.048 AAPL 98.00 100
By default we are taking the asof of the quotes
>>> pd.merge_asof(trades, quotes,
... on='time',
... by='ticker')
time ticker price quantity bid ask
0 2016-05-25 13:30:00.023 MSFT 51.95 75 51.95 51.96
1 2016-05-25 13:30:00.038 MSFT 51.95 155 51.97 51.98
2 2016-05-25 13:30:00.048 GOOG 720.77 100 720.50 720.93
3 2016-05-25 13:30:00.048 GOOG 720.92 100 720.50 720.93
4 2016-05-25 13:30:00.048 AAPL 98.00 100 NaN NaN
We only asof within 2ms between the quote time and the trade time
>>> pd.merge_asof(trades, quotes,
... on='time',
... by='ticker',
... tolerance=pd.Timedelta('2ms'))
time ticker price quantity bid ask
0 2016-05-25 13:30:00.023 MSFT 51.95 75 51.95 51.96
1 2016-05-25 13:30:00.038 MSFT 51.95 155 NaN NaN
2 2016-05-25 13:30:00.048 GOOG 720.77 100 720.50 720.93
3 2016-05-25 13:30:00.048 GOOG 720.92 100 720.50 720.93
4 2016-05-25 13:30:00.048 AAPL 98.00 100 NaN NaN
We only asof within 10ms between the quote time and the trade time
and we exclude exact matches on time. However *prior* data will
propagate forward
>>> pd.merge_asof(trades, quotes,
... on='time',
... by='ticker',
... tolerance=pd.Timedelta('10ms'),
... allow_exact_matches=False)
time ticker price quantity bid ask
0 2016-05-25 13:30:00.023 MSFT 51.95 75 NaN NaN
1 2016-05-25 13:30:00.038 MSFT 51.95 155 51.97 51.98
2 2016-05-25 13:30:00.048 GOOG 720.77 100 NaN NaN
3 2016-05-25 13:30:00.048 GOOG 720.92 100 NaN NaN
4 2016-05-25 13:30:00.048 AAPL 98.00 100 NaN NaN
"""
op = _AsOfMerge(
left,
right,
on=on,
left_on=left_on,
right_on=right_on,
left_index=left_index,
right_index=right_index,
by=by,
left_by=left_by,
right_by=right_by,
suffixes=suffixes,
how="asof",
tolerance=tolerance,
allow_exact_matches=allow_exact_matches,
direction=direction,
)
return op.get_result()
# TODO: transformations??
# TODO: only copy DataFrames when modification necessary
class _MergeOperation:
"""
Perform a database (SQL) merge operation between two DataFrame objects
using either columns as keys or their row indexes
"""
_merge_type = "merge"
def __init__(
self,
left,
right,
how="inner",
on=None,
left_on=None,
right_on=None,
axis=1,
left_index=False,
right_index=False,
sort=True,
suffixes=("_x", "_y"),
copy=True,
indicator=False,
validate=None,
):
left = validate_operand(left)
right = validate_operand(right)
self.left = self.orig_left = left
self.right = self.orig_right = right
self.how = how
self.axis = axis
self.on = com.maybe_make_list(on)
self.left_on = com.maybe_make_list(left_on)
self.right_on = com.maybe_make_list(right_on)
self.copy = copy
self.suffixes = suffixes
self.sort = sort
self.left_index = left_index
self.right_index = right_index
self.indicator = indicator
if isinstance(self.indicator, str):
self.indicator_name = self.indicator
elif isinstance(self.indicator, bool):
self.indicator_name = "_merge" if self.indicator else None
else:
raise ValueError(
"indicator option can only accept boolean or string arguments"
)
if not is_bool(left_index):
raise ValueError(
"left_index parameter must be of type bool, not "
"{left_index}".format(left_index=type(left_index))
)
if not is_bool(right_index):
raise ValueError(
"right_index parameter must be of type bool, not "
"{right_index}".format(right_index=type(right_index))
)
# warn user when merging between different levels
if left.columns.nlevels != right.columns.nlevels:
msg = (
"merging between different levels can give an unintended "
"result ({left} levels on the left, {right} on the right)"
).format(left=left.columns.nlevels, right=right.columns.nlevels)
warnings.warn(msg, UserWarning)
self._validate_specification()
# note this function has side effects
(
self.left_join_keys,
self.right_join_keys,
self.join_names,
) = self._get_merge_keys()
# validate the merge keys dtypes. We may need to coerce
# to avoid incompat dtypes
self._maybe_coerce_merge_keys()
# If argument passed to validate,
# check if columns specified as unique
# are in fact unique.
if validate is not None:
self._validate(validate)
def get_result(self):
if self.indicator:
self.left, self.right = self._indicator_pre_merge(self.left, self.right)
join_index, left_indexer, right_indexer = self._get_join_info()
ldata, rdata = self.left._data, self.right._data
lsuf, rsuf = self.suffixes
llabels, rlabels = _items_overlap_with_suffix(
ldata.items, lsuf, rdata.items, rsuf
)
lindexers = {1: left_indexer} if left_indexer is not None else {}
rindexers = {1: right_indexer} if right_indexer is not None else {}
result_data = concatenate_block_managers(
[(ldata, lindexers), (rdata, rindexers)],
axes=[llabels.append(rlabels), join_index],
concat_axis=0,
copy=self.copy,
)
typ = self.left._constructor
result = typ(result_data).__finalize__(self, method=self._merge_type)
if self.indicator:
result = self._indicator_post_merge(result)
self._maybe_add_join_keys(result, left_indexer, right_indexer)
self._maybe_restore_index_levels(result)
return result
def _indicator_pre_merge(self, left, right):
columns = left.columns.union(right.columns)
for i in ["_left_indicator", "_right_indicator"]:
if i in columns:
raise ValueError(
"Cannot use `indicator=True` option when "
"data contains a column named {name}".format(name=i)
)
if self.indicator_name in columns:
raise ValueError(
"Cannot use name of an existing column for indicator column"
)
left = left.copy()
right = right.copy()
left["_left_indicator"] = 1
left["_left_indicator"] = left["_left_indicator"].astype("int8")
right["_right_indicator"] = 2
right["_right_indicator"] = right["_right_indicator"].astype("int8")
return left, right
def _indicator_post_merge(self, result):
result["_left_indicator"] = result["_left_indicator"].fillna(0)
result["_right_indicator"] = result["_right_indicator"].fillna(0)
result[self.indicator_name] = Categorical(
(result["_left_indicator"] + result["_right_indicator"]),
categories=[1, 2, 3],
)
result[self.indicator_name] = result[self.indicator_name].cat.rename_categories(
["left_only", "right_only", "both"]
)
result = result.drop(labels=["_left_indicator", "_right_indicator"], axis=1)
return result
def _maybe_restore_index_levels(self, result):
"""
Restore index levels specified as `on` parameters
Here we check for cases where `self.left_on` and `self.right_on` pairs
each reference an index level in their respective DataFrames. The
joined columns corresponding to these pairs are then restored to the
index of `result`.
**Note:** This method has side effects. It modifies `result` in-place
Parameters
----------
result: DataFrame
merge result
Returns
-------
None
"""
names_to_restore = []
for name, left_key, right_key in zip(
self.join_names, self.left_on, self.right_on
):
if (
self.orig_left._is_level_reference(left_key)
and self.orig_right._is_level_reference(right_key)
and name not in result.index.names
):
names_to_restore.append(name)
if names_to_restore:
result.set_index(names_to_restore, inplace=True)
def _maybe_add_join_keys(self, result, left_indexer, right_indexer):
left_has_missing = None
right_has_missing = None
keys = zip(self.join_names, self.left_on, self.right_on)
for i, (name, lname, rname) in enumerate(keys):
if not _should_fill(lname, rname):
continue
take_left, take_right = None, None
if name in result:
if left_indexer is not None and right_indexer is not None:
if name in self.left:
if left_has_missing is None:
left_has_missing = (left_indexer == -1).any()
if left_has_missing:
take_right = self.right_join_keys[i]
if not is_dtype_equal(
result[name].dtype, self.left[name].dtype
):
take_left = self.left[name]._values
elif name in self.right:
if right_has_missing is None:
right_has_missing = (right_indexer == -1).any()
if right_has_missing:
take_left = self.left_join_keys[i]
if not is_dtype_equal(
result[name].dtype, self.right[name].dtype
):
take_right = self.right[name]._values
elif left_indexer is not None and is_array_like(self.left_join_keys[i]):
take_left = self.left_join_keys[i]
take_right = self.right_join_keys[i]
if take_left is not None or take_right is not None:
if take_left is None:
lvals = result[name]._values
else:
lfill = na_value_for_dtype(take_left.dtype)
lvals = algos.take_1d(take_left, left_indexer, fill_value=lfill)
if take_right is None:
rvals = result[name]._values
else:
rfill = na_value_for_dtype(take_right.dtype)
rvals = algos.take_1d(take_right, right_indexer, fill_value=rfill)
# if we have an all missing left_indexer
# make sure to just use the right values
mask = left_indexer == -1
if mask.all():
key_col = rvals
else:
key_col = Index(lvals).where(~mask, rvals)
if result._is_label_reference(name):
result[name] = key_col
elif result._is_level_reference(name):
if isinstance(result.index, MultiIndex):
key_col.name = name
idx_list = [
result.index.get_level_values(level_name)
if level_name != name
else key_col
for level_name in result.index.names
]
result.set_index(idx_list, inplace=True)
else:
result.index = Index(key_col, name=name)
else:
result.insert(i, name or "key_{i}".format(i=i), key_col)
def _get_join_indexers(self):
""" return the join indexers """
return _get_join_indexers(
self.left_join_keys, self.right_join_keys, sort=self.sort, how=self.how
)
def _get_join_info(self):
left_ax = self.left._data.axes[self.axis]
right_ax = self.right._data.axes[self.axis]
if self.left_index and self.right_index and self.how != "asof":
join_index, left_indexer, right_indexer = left_ax.join(
right_ax, how=self.how, return_indexers=True, sort=self.sort
)
elif self.right_index and self.how == "left":
join_index, left_indexer, right_indexer = _left_join_on_index(
left_ax, right_ax, self.left_join_keys, sort=self.sort
)
elif self.left_index and self.how == "right":
join_index, right_indexer, left_indexer = _left_join_on_index(
right_ax, left_ax, self.right_join_keys, sort=self.sort
)
else:
(left_indexer, right_indexer) = self._get_join_indexers()
if self.right_index:
if len(self.left) > 0:
join_index = self._create_join_index(
self.left.index,
self.right.index,
left_indexer,
right_indexer,
how="right",
)
else:
join_index = self.right.index.take(right_indexer)
left_indexer = np.array([-1] * len(join_index))
elif self.left_index:
if len(self.right) > 0:
join_index = self._create_join_index(
self.right.index,
self.left.index,
right_indexer,
left_indexer,
how="left",
)
else:
join_index = self.left.index.take(left_indexer)
right_indexer = np.array([-1] * len(join_index))
else:
join_index = Index(np.arange(len(left_indexer)))
if len(join_index) == 0:
join_index = join_index.astype(object)
return join_index, left_indexer, right_indexer
def _create_join_index(
self, index, other_index, indexer, other_indexer, how="left"
):
"""
Create a join index by rearranging one index to match another
Parameters
----------
index: Index being rearranged
other_index: Index used to supply values not found in index
indexer: how to rearrange index
how: replacement is only necessary if indexer based on other_index
Returns
-------
join_index
"""
if self.how in (how, "outer") and not isinstance(other_index, MultiIndex):
# if final index requires values in other_index but not target
# index, indexer may hold missing (-1) values, causing Index.take
# to take the final value in target index. So, we set the last
# element to be the desired fill value. We do not use allow_fill
# and fill_value because it throws a ValueError on integer indices
mask = indexer == -1
if np.any(mask):
fill_value = na_value_for_dtype(index.dtype, compat=False)
index = index.append(Index([fill_value]))
return index.take(indexer)
def _get_merge_keys(self):
"""
Note: has side effects (copy/delete key columns)
Parameters
----------
left
right
on
Returns
-------
left_keys, right_keys
"""
left_keys = []
right_keys = []
join_names = []
right_drop = []
left_drop = []
left, right = self.left, self.right
is_lkey = lambda x: is_array_like(x) and len(x) == len(left)
is_rkey = lambda x: is_array_like(x) and len(x) == len(right)
# Note that pd.merge_asof() has separate 'on' and 'by' parameters. A
# user could, for example, request 'left_index' and 'left_by'. In a
# regular pd.merge(), users cannot specify both 'left_index' and
# 'left_on'. (Instead, users have a MultiIndex). That means the
# self.left_on in this function is always empty in a pd.merge(), but
# a pd.merge_asof(left_index=True, left_by=...) will result in a
# self.left_on array with a None in the middle of it. This requires
# a work-around as designated in the code below.
# See _validate_specification() for where this happens.
# ugh, spaghetti re #733
if _any(self.left_on) and _any(self.right_on):
for lk, rk in zip(self.left_on, self.right_on):
if is_lkey(lk):
left_keys.append(lk)
if is_rkey(rk):
right_keys.append(rk)
join_names.append(None) # what to do?
else:
if rk is not None:
right_keys.append(right._get_label_or_level_values(rk))
join_names.append(rk)
else:
# work-around for merge_asof(right_index=True)
right_keys.append(right.index)
join_names.append(right.index.name)
else:
if not is_rkey(rk):
if rk is not None:
right_keys.append(right._get_label_or_level_values(rk))
else:
# work-around for merge_asof(right_index=True)
right_keys.append(right.index)
if lk is not None and lk == rk:
# avoid key upcast in corner case (length-0)
if len(left) > 0:
right_drop.append(rk)
else:
left_drop.append(lk)
else:
right_keys.append(rk)
if lk is not None:
left_keys.append(left._get_label_or_level_values(lk))
join_names.append(lk)
else:
# work-around for merge_asof(left_index=True)
left_keys.append(left.index)
join_names.append(left.index.name)
elif _any(self.left_on):
for k in self.left_on:
if is_lkey(k):
left_keys.append(k)
join_names.append(None)
else:
left_keys.append(left._get_label_or_level_values(k))
join_names.append(k)
if isinstance(self.right.index, MultiIndex):
right_keys = [
lev._values.take(lev_codes)
for lev, lev_codes in zip(
self.right.index.levels, self.right.index.codes
)
]
else:
right_keys = [self.right.index._values]
elif _any(self.right_on):
for k in self.right_on:
if is_rkey(k):
right_keys.append(k)
join_names.append(None)
else:
right_keys.append(right._get_label_or_level_values(k))
join_names.append(k)
if isinstance(self.left.index, MultiIndex):
left_keys = [
lev._values.take(lev_codes)
for lev, lev_codes in zip(
self.left.index.levels, self.left.index.codes
)
]
else:
left_keys = [self.left.index.values]
if left_drop:
self.left = self.left._drop_labels_or_levels(left_drop)
if right_drop:
self.right = self.right._drop_labels_or_levels(right_drop)
return left_keys, right_keys, join_names
def _maybe_coerce_merge_keys(self):
# we have valid mergees but we may have to further
# coerce these if they are originally incompatible types
#
# for example if these are categorical, but are not dtype_equal
# or if we have object and integer dtypes
for lk, rk, name in zip(
self.left_join_keys, self.right_join_keys, self.join_names
):
if (len(lk) and not len(rk)) or (not len(lk) and len(rk)):
continue
lk_is_cat = is_categorical_dtype(lk)
rk_is_cat = is_categorical_dtype(rk)
lk_is_object = is_object_dtype(lk)
rk_is_object = is_object_dtype(rk)
# if either left or right is a categorical
# then the must match exactly in categories & ordered
if lk_is_cat and rk_is_cat:
if lk.is_dtype_equal(rk):
continue
elif lk_is_cat or rk_is_cat:
pass
elif is_dtype_equal(lk.dtype, rk.dtype):
continue
msg = (
"You are trying to merge on {lk_dtype} and "
"{rk_dtype} columns. If you wish to proceed "
"you should use pd.concat".format(lk_dtype=lk.dtype, rk_dtype=rk.dtype)
)
# if we are numeric, then allow differing
# kinds to proceed, eg. int64 and int8, int and float
# further if we are object, but we infer to
# the same, then proceed
if is_numeric_dtype(lk) and is_numeric_dtype(rk):
if lk.dtype.kind == rk.dtype.kind:
continue
# check whether ints and floats
elif is_integer_dtype(rk) and is_float_dtype(lk):
if not (lk == lk.astype(rk.dtype))[~np.isnan(lk)].all():
warnings.warn(
"You are merging on int and float "
"columns where the float values "
"are not equal to their int "
"representation",
UserWarning,
)
continue
elif is_float_dtype(rk) and is_integer_dtype(lk):
if not (rk == rk.astype(lk.dtype))[~np.isnan(rk)].all():
warnings.warn(
"You are merging on int and float "
"columns where the float values "
"are not equal to their int "
"representation",
UserWarning,
)
continue
# let's infer and see if we are ok
elif lib.infer_dtype(lk, skipna=False) == lib.infer_dtype(
rk, skipna=False
):
continue
# Check if we are trying to merge on obviously
# incompatible dtypes GH 9780, GH 15800
# bool values are coerced to object
elif (lk_is_object and is_bool_dtype(rk)) or (
is_bool_dtype(lk) and rk_is_object
):
pass
# object values are allowed to be merged
elif (lk_is_object and is_numeric_dtype(rk)) or (
is_numeric_dtype(lk) and rk_is_object
):
inferred_left = lib.infer_dtype(lk, skipna=False)
inferred_right = lib.infer_dtype(rk, skipna=False)
bool_types = ["integer", "mixed-integer", "boolean", "empty"]
string_types = ["string", "unicode", "mixed", "bytes", "empty"]
# inferred bool
if inferred_left in bool_types and inferred_right in bool_types:
pass
# unless we are merging non-string-like with string-like
elif (
inferred_left in string_types and inferred_right not in string_types
) or (
inferred_right in string_types and inferred_left not in string_types
):
raise ValueError(msg)
# datetimelikes must match exactly
elif is_datetimelike(lk) and not is_datetimelike(rk):
raise ValueError(msg)
elif not is_datetimelike(lk) and is_datetimelike(rk):
raise ValueError(msg)
elif is_datetime64tz_dtype(lk) and not is_datetime64tz_dtype(rk):
raise ValueError(msg)
elif not is_datetime64tz_dtype(lk) and is_datetime64tz_dtype(rk):
raise ValueError(msg)
elif lk_is_object and rk_is_object:
continue
# Houston, we have a problem!
# let's coerce to object if the dtypes aren't
# categorical, otherwise coerce to the category
# dtype. If we coerced categories to object,
# then we would lose type information on some
# columns, and end up trying to merge
# incompatible dtypes. See GH 16900.
if name in self.left.columns:
typ = lk.categories.dtype if lk_is_cat else object
self.left = self.left.assign(**{name: self.left[name].astype(typ)})
if name in self.right.columns:
typ = rk.categories.dtype if rk_is_cat else object
self.right = self.right.assign(**{name: self.right[name].astype(typ)})
def _validate_specification(self):
# Hm, any way to make this logic less complicated??
if self.on is None and self.left_on is None and self.right_on is None:
if self.left_index and self.right_index:
self.left_on, self.right_on = (), ()
elif self.left_index:
if self.right_on is None:
raise MergeError("Must pass right_on or right_index=True")
elif self.right_index:
if self.left_on is None:
raise MergeError("Must pass left_on or left_index=True")
else:
# use the common columns
common_cols = self.left.columns.intersection(self.right.columns)
if len(common_cols) == 0:
raise MergeError(
"No common columns to perform merge on. "
"Merge options: left_on={lon}, right_on={ron}, "
"left_index={lidx}, right_index={ridx}".format(
lon=self.left_on,
ron=self.right_on,
lidx=self.left_index,
ridx=self.right_index,
)
)
if not common_cols.is_unique:
raise MergeError(
"Data columns not unique: {common!r}".format(common=common_cols)
)
self.left_on = self.right_on = common_cols
elif self.on is not None:
if self.left_on is not None or self.right_on is not None:
raise MergeError(
'Can only pass argument "on" OR "left_on" '
'and "right_on", not a combination of both.'
)
self.left_on = self.right_on = self.on
elif self.left_on is not None:
n = len(self.left_on)
if self.right_index:
if len(self.left_on) != self.right.index.nlevels:
raise ValueError(
"len(left_on) must equal the number "
'of levels in the index of "right"'
)
self.right_on = [None] * n
elif self.right_on is not None:
n = len(self.right_on)
if self.left_index:
if len(self.right_on) != self.left.index.nlevels:
raise ValueError(
"len(right_on) must equal the number "
'of levels in the index of "left"'
)
self.left_on = [None] * n
if len(self.right_on) != len(self.left_on):
raise ValueError("len(right_on) must equal len(left_on)")
def _validate(self, validate):
# Check uniqueness of each
if self.left_index:
left_unique = self.orig_left.index.is_unique
else:
left_unique = MultiIndex.from_arrays(self.left_join_keys).is_unique
if self.right_index:
right_unique = self.orig_right.index.is_unique
else:
right_unique = MultiIndex.from_arrays(self.right_join_keys).is_unique
# Check data integrity
if validate in ["one_to_one", "1:1"]:
if not left_unique and not right_unique:
raise MergeError(
"Merge keys are not unique in either left"
" or right dataset; not a one-to-one merge"
)
elif not left_unique:
raise MergeError(
"Merge keys are not unique in left dataset;"
" not a one-to-one merge"
)
elif not right_unique:
raise MergeError(
"Merge keys are not unique in right dataset;"
" not a one-to-one merge"
)
elif validate in ["one_to_many", "1:m"]:
if not left_unique:
raise MergeError(
"Merge keys are not unique in left dataset;"
" not a one-to-many merge"
)
elif validate in ["many_to_one", "m:1"]:
if not right_unique:
raise MergeError(
"Merge keys are not unique in right dataset;"
" not a many-to-one merge"
)
elif validate in ["many_to_many", "m:m"]:
pass
else:
raise ValueError("Not a valid argument for validate")
def _get_join_indexers(left_keys, right_keys, sort=False, how="inner", **kwargs):
"""
Parameters
----------
left_keys: ndarray, Index, Series
right_keys: ndarray, Index, Series
sort: bool, default False
how: string {'inner', 'outer', 'left', 'right'}, default 'inner'
Returns
-------
tuple of (left_indexer, right_indexer)
indexers into the left_keys, right_keys
"""
assert len(left_keys) == len(
right_keys
), "left_key and right_keys must be the same length"
# bind `sort` arg. of _factorize_keys
fkeys = partial(_factorize_keys, sort=sort)
# get left & right join labels and num. of levels at each location
llab, rlab, shape = map(list, zip(*map(fkeys, left_keys, right_keys)))
# get flat i8 keys from label lists
lkey, rkey = _get_join_keys(llab, rlab, shape, sort)
# factorize keys to a dense i8 space
# `count` is the num. of unique keys
# set(lkey) | set(rkey) == range(count)
lkey, rkey, count = fkeys(lkey, rkey)
# preserve left frame order if how == 'left' and sort == False
kwargs = copy.copy(kwargs)
if how == "left":
kwargs["sort"] = sort
join_func = _join_functions[how]
return join_func(lkey, rkey, count, **kwargs)
def _restore_dropped_levels_multijoin(
left, right, dropped_level_names, join_index, lindexer, rindexer
):
"""
*this is an internal non-public method*
Returns the levels, labels and names of a multi-index to multi-index join.
Depending on the type of join, this method restores the appropriate
dropped levels of the joined multi-index.
The method relies on lidx, rindexer which hold the index positions of
left and right, where a join was feasible
Parameters
----------
left : MultiIndex
left index
right : MultiIndex
right index
dropped_level_names : str array
list of non-common level names
join_index : MultiIndex
the index of the join between the
common levels of left and right
lindexer : intp array
left indexer
rindexer : intp array
right indexer
Returns
-------
levels : list of Index
levels of combined multiindexes
labels : intp array
labels of combined multiindexes
names : str array
names of combined multiindexes
"""
def _convert_to_mulitindex(index):
if isinstance(index, MultiIndex):
return index
else:
return MultiIndex.from_arrays([index.values], names=[index.name])
# For multi-multi joins with one overlapping level,
# the returned index if of type Index
# Assure that join_index is of type MultiIndex
# so that dropped levels can be appended
join_index = _convert_to_mulitindex(join_index)
join_levels = join_index.levels
join_codes = join_index.codes
join_names = join_index.names
# lindexer and rindexer hold the indexes where the join occurred
# for left and right respectively. If left/right is None then
# the join occurred on all indices of left/right
if lindexer is None:
lindexer = range(left.size)
if rindexer is None:
rindexer = range(right.size)
# Iterate through the levels that must be restored
for dropped_level_name in dropped_level_names:
if dropped_level_name in left.names:
idx = left
indexer = lindexer
else:
idx = right
indexer = rindexer
# The index of the level name to be restored
name_idx = idx.names.index(dropped_level_name)
restore_levels = idx.levels[name_idx]
# Inject -1 in the codes list where a join was not possible
# IOW indexer[i]=-1
codes = idx.codes[name_idx]
restore_codes = algos.take_nd(codes, indexer, fill_value=-1)
join_levels = join_levels + [restore_levels]
join_codes = join_codes + [restore_codes]
join_names = join_names + [dropped_level_name]
return join_levels, join_codes, join_names
class _OrderedMerge(_MergeOperation):
_merge_type = "ordered_merge"
def __init__(
self,
left,
right,
on=None,
left_on=None,
right_on=None,
left_index=False,
right_index=False,
axis=1,
suffixes=("_x", "_y"),
copy=True,
fill_method=None,
how="outer",
):
self.fill_method = fill_method
_MergeOperation.__init__(
self,
left,
right,
on=on,
left_on=left_on,
left_index=left_index,
right_index=right_index,
right_on=right_on,
axis=axis,
how=how,
suffixes=suffixes,
sort=True, # factorize sorts
)
def get_result(self):
join_index, left_indexer, right_indexer = self._get_join_info()
# this is a bit kludgy
ldata, rdata = self.left._data, self.right._data
lsuf, rsuf = self.suffixes
llabels, rlabels = _items_overlap_with_suffix(
ldata.items, lsuf, rdata.items, rsuf
)
if self.fill_method == "ffill":
left_join_indexer = libjoin.ffill_indexer(left_indexer)
right_join_indexer = libjoin.ffill_indexer(right_indexer)
else:
left_join_indexer = left_indexer
right_join_indexer = right_indexer
lindexers = {1: left_join_indexer} if left_join_indexer is not None else {}
rindexers = {1: right_join_indexer} if right_join_indexer is not None else {}
result_data = concatenate_block_managers(
[(ldata, lindexers), (rdata, rindexers)],
axes=[llabels.append(rlabels), join_index],
concat_axis=0,
copy=self.copy,
)
typ = self.left._constructor
result = typ(result_data).__finalize__(self, method=self._merge_type)
self._maybe_add_join_keys(result, left_indexer, right_indexer)
return result
def _asof_function(direction):
name = "asof_join_{dir}".format(dir=direction)
return getattr(libjoin, name, None)
def _asof_by_function(direction):
name = "asof_join_{dir}_on_X_by_Y".format(dir=direction)
return getattr(libjoin, name, None)
_type_casters = {
"int64_t": ensure_int64,
"double": ensure_float64,
"object": ensure_object,
}
def _get_cython_type_upcast(dtype):
""" Upcast a dtype to 'int64_t', 'double', or 'object' """
if is_integer_dtype(dtype):
return "int64_t"
elif is_float_dtype(dtype):
return "double"
else:
return "object"
class _AsOfMerge(_OrderedMerge):
_merge_type = "asof_merge"
def __init__(
self,
left,
right,
on=None,
left_on=None,
right_on=None,
left_index=False,
right_index=False,
by=None,
left_by=None,
right_by=None,
axis=1,
suffixes=("_x", "_y"),
copy=True,
fill_method=None,
how="asof",
tolerance=None,
allow_exact_matches=True,
direction="backward",
):
self.by = by
self.left_by = left_by
self.right_by = right_by
self.tolerance = tolerance
self.allow_exact_matches = allow_exact_matches
self.direction = direction
_OrderedMerge.__init__(
self,
left,
right,
on=on,
left_on=left_on,
right_on=right_on,
left_index=left_index,
right_index=right_index,
axis=axis,
how=how,
suffixes=suffixes,
fill_method=fill_method,
)
def _validate_specification(self):
super()._validate_specification()
# we only allow on to be a single item for on
if len(self.left_on) != 1 and not self.left_index:
raise MergeError("can only asof on a key for left")
if len(self.right_on) != 1 and not self.right_index:
raise MergeError("can only asof on a key for right")
if self.left_index and isinstance(self.left.index, MultiIndex):
raise MergeError("left can only have one index")
if self.right_index and isinstance(self.right.index, MultiIndex):
raise MergeError("right can only have one index")
# set 'by' columns
if self.by is not None:
if self.left_by is not None or self.right_by is not None:
raise MergeError("Can only pass by OR left_by and right_by")
self.left_by = self.right_by = self.by
if self.left_by is None and self.right_by is not None:
raise MergeError("missing left_by")
if self.left_by is not None and self.right_by is None:
raise MergeError("missing right_by")
# add 'by' to our key-list so we can have it in the
# output as a key
if self.left_by is not None:
if not is_list_like(self.left_by):
self.left_by = [self.left_by]
if not is_list_like(self.right_by):
self.right_by = [self.right_by]
if len(self.left_by) != len(self.right_by):
raise MergeError("left_by and right_by must be same length")
self.left_on = self.left_by + list(self.left_on)
self.right_on = self.right_by + list(self.right_on)
# check 'direction' is valid
if self.direction not in ["backward", "forward", "nearest"]:
raise MergeError(
"direction invalid: {direction}".format(direction=self.direction)
)
@property
def _asof_key(self):
""" This is our asof key, the 'on' """
return self.left_on[-1]
def _get_merge_keys(self):
# note this function has side effects
(left_join_keys, right_join_keys, join_names) = super()._get_merge_keys()
# validate index types are the same
for i, (lk, rk) in enumerate(zip(left_join_keys, right_join_keys)):
if not is_dtype_equal(lk.dtype, rk.dtype):
if is_categorical_dtype(lk.dtype) and is_categorical_dtype(rk.dtype):
# The generic error message is confusing for categoricals.
#
# In this function, the join keys include both the original
# ones of the merge_asof() call, and also the keys passed
# to its by= argument. Unordered but equal categories
# are not supported for the former, but will fail
# later with a ValueError, so we don't *need* to check
# for them here.
msg = (
"incompatible merge keys [{i}] {lkdtype} and "
"{rkdtype}, both sides category, but not equal ones".format(
i=i, lkdtype=repr(lk.dtype), rkdtype=repr(rk.dtype)
)
)
else:
msg = (
"incompatible merge keys [{i}] {lkdtype} and "
"{rkdtype}, must be the same type".format(
i=i, lkdtype=repr(lk.dtype), rkdtype=repr(rk.dtype)
)
)
raise MergeError(msg)
# validate tolerance; datetime.timedelta or Timedelta if we have a DTI
if self.tolerance is not None:
if self.left_index:
lt = self.left.index
else:
lt = left_join_keys[-1]
msg = (
"incompatible tolerance {tolerance}, must be compat "
"with type {lkdtype}".format(
tolerance=type(self.tolerance), lkdtype=repr(lt.dtype)
)
)
if is_datetimelike(lt):
if not isinstance(self.tolerance, datetime.timedelta):
raise MergeError(msg)
if self.tolerance < Timedelta(0):
raise MergeError("tolerance must be positive")
elif is_int64_dtype(lt):
if not is_integer(self.tolerance):
raise MergeError(msg)
if self.tolerance < 0:
raise MergeError("tolerance must be positive")
elif is_float_dtype(lt):
if not is_number(self.tolerance):
raise MergeError(msg)
if self.tolerance < 0:
raise MergeError("tolerance must be positive")
else:
raise MergeError("key must be integer, timestamp or float")
# validate allow_exact_matches
if not is_bool(self.allow_exact_matches):
msg = "allow_exact_matches must be boolean, passed {passed}"
raise MergeError(msg.format(passed=self.allow_exact_matches))
return left_join_keys, right_join_keys, join_names
def _get_join_indexers(self):
""" return the join indexers """
def flip(xs):
""" unlike np.transpose, this returns an array of tuples """
xs = [
x if not is_extension_array_dtype(x) else x._ndarray_values for x in xs
]
labels = list(string.ascii_lowercase[: len(xs)])
dtypes = [x.dtype for x in xs]
labeled_dtypes = list(zip(labels, dtypes))
return np.array(list(zip(*xs)), labeled_dtypes)
# values to compare
left_values = (
self.left.index.values if self.left_index else self.left_join_keys[-1]
)
right_values = (
self.right.index.values if self.right_index else self.right_join_keys[-1]
)
tolerance = self.tolerance
# we require sortedness and non-null values in the join keys
msg_sorted = "{side} keys must be sorted"
msg_missings = "Merge keys contain null values on {side} side"
if not Index(left_values).is_monotonic:
if isnull(left_values).any():
raise ValueError(msg_missings.format(side="left"))
else:
raise ValueError(msg_sorted.format(side="left"))
if not Index(right_values).is_monotonic:
if isnull(right_values).any():
raise ValueError(msg_missings.format(side="right"))
else:
raise ValueError(msg_sorted.format(side="right"))
# initial type conversion as needed
if needs_i8_conversion(left_values):
left_values = left_values.view("i8")
right_values = right_values.view("i8")
if tolerance is not None:
tolerance = Timedelta(tolerance)
tolerance = tolerance.value
# a "by" parameter requires special handling
if self.left_by is not None:
# remove 'on' parameter from values if one existed
if self.left_index and self.right_index:
left_by_values = self.left_join_keys
right_by_values = self.right_join_keys
else:
left_by_values = self.left_join_keys[0:-1]
right_by_values = self.right_join_keys[0:-1]
# get tuple representation of values if more than one
if len(left_by_values) == 1:
left_by_values = left_by_values[0]
right_by_values = right_by_values[0]
else:
left_by_values = flip(left_by_values)
right_by_values = flip(right_by_values)
# upcast 'by' parameter because HashTable is limited
by_type = _get_cython_type_upcast(left_by_values.dtype)
by_type_caster = _type_casters[by_type]
left_by_values = by_type_caster(left_by_values)
right_by_values = by_type_caster(right_by_values)
# choose appropriate function by type
func = _asof_by_function(self.direction)
return func(
left_values,
right_values,
left_by_values,
right_by_values,
self.allow_exact_matches,
tolerance,
)
else:
# choose appropriate function by type
func = _asof_function(self.direction)
return func(left_values, right_values, self.allow_exact_matches, tolerance)
def _get_multiindex_indexer(join_keys, index, sort):
# bind `sort` argument
fkeys = partial(_factorize_keys, sort=sort)
# left & right join labels and num. of levels at each location
rcodes, lcodes, shape = map(list, zip(*map(fkeys, index.levels, join_keys)))
if sort:
rcodes = list(map(np.take, rcodes, index.codes))
else:
i8copy = lambda a: a.astype("i8", subok=False, copy=True)
rcodes = list(map(i8copy, index.codes))
# fix right labels if there were any nulls
for i in range(len(join_keys)):
mask = index.codes[i] == -1
if mask.any():
# check if there already was any nulls at this location
# if there was, it is factorized to `shape[i] - 1`
a = join_keys[i][lcodes[i] == shape[i] - 1]
if a.size == 0 or not a[0] != a[0]:
shape[i] += 1
rcodes[i][mask] = shape[i] - 1
# get flat i8 join keys
lkey, rkey = _get_join_keys(lcodes, rcodes, shape, sort)
# factorize keys to a dense i8 space
lkey, rkey, count = fkeys(lkey, rkey)
return libjoin.left_outer_join(lkey, rkey, count, sort=sort)
def _get_single_indexer(join_key, index, sort=False):
left_key, right_key, count = _factorize_keys(join_key, index, sort=sort)
left_indexer, right_indexer = libjoin.left_outer_join(
ensure_int64(left_key), ensure_int64(right_key), count, sort=sort
)
return left_indexer, right_indexer
def _left_join_on_index(left_ax, right_ax, join_keys, sort=False):
if len(join_keys) > 1:
if not (
(isinstance(right_ax, MultiIndex) and len(join_keys) == right_ax.nlevels)
):
raise AssertionError(
"If more than one join key is given then "
"'right_ax' must be a MultiIndex and the "
"number of join keys must be the number of "
"levels in right_ax"
)
left_indexer, right_indexer = _get_multiindex_indexer(
join_keys, right_ax, sort=sort
)
else:
jkey = join_keys[0]
left_indexer, right_indexer = _get_single_indexer(jkey, right_ax, sort=sort)
if sort or len(left_ax) != len(left_indexer):
# if asked to sort or there are 1-to-many matches
join_index = left_ax.take(left_indexer)
return join_index, left_indexer, right_indexer
# left frame preserves order & length of its index
return left_ax, None, right_indexer
def _right_outer_join(x, y, max_groups):
right_indexer, left_indexer = libjoin.left_outer_join(y, x, max_groups)
return left_indexer, right_indexer
_join_functions = {
"inner": libjoin.inner_join,
"left": libjoin.left_outer_join,
"right": _right_outer_join,
"outer": libjoin.full_outer_join,
}
def _factorize_keys(lk, rk, sort=True):
# Some pre-processing for non-ndarray lk / rk
if is_datetime64tz_dtype(lk) and is_datetime64tz_dtype(rk):
lk = getattr(lk, "_values", lk)._data
rk = getattr(rk, "_values", rk)._data
elif (
is_categorical_dtype(lk) and is_categorical_dtype(rk) and lk.is_dtype_equal(rk)
):
if lk.categories.equals(rk.categories):
# if we exactly match in categories, allow us to factorize on codes
rk = rk.codes
else:
# Same categories in different orders -> recode
rk = _recode_for_categories(rk.codes, rk.categories, lk.categories)
lk = ensure_int64(lk.codes)
rk = ensure_int64(rk)
elif (
is_extension_array_dtype(lk.dtype)
and is_extension_array_dtype(rk.dtype)
and lk.dtype == rk.dtype
):
lk, _ = lk._values_for_factorize()
rk, _ = rk._values_for_factorize()
if is_integer_dtype(lk) and is_integer_dtype(rk):
# GH#23917 TODO: needs tests for case where lk is integer-dtype
# and rk is datetime-dtype
klass = libhashtable.Int64Factorizer
lk = ensure_int64(com.values_from_object(lk))
rk = ensure_int64(com.values_from_object(rk))
elif issubclass(lk.dtype.type, (np.timedelta64, np.datetime64)) and issubclass(
rk.dtype.type, (np.timedelta64, np.datetime64)
):
# GH#23917 TODO: Needs tests for non-matching dtypes
klass = libhashtable.Int64Factorizer
lk = ensure_int64(com.values_from_object(lk))
rk = ensure_int64(com.values_from_object(rk))
else:
klass = libhashtable.Factorizer
lk = ensure_object(lk)
rk = ensure_object(rk)
rizer = klass(max(len(lk), len(rk)))
llab = rizer.factorize(lk)
rlab = rizer.factorize(rk)
count = rizer.get_count()
if sort:
uniques = rizer.uniques.to_array()
llab, rlab = _sort_labels(uniques, llab, rlab)
# NA group
lmask = llab == -1
lany = lmask.any()
rmask = rlab == -1
rany = rmask.any()
if lany or rany:
if lany:
np.putmask(llab, lmask, count)
if rany:
np.putmask(rlab, rmask, count)
count += 1
return llab, rlab, count
def _sort_labels(uniques, left, right):
if not isinstance(uniques, np.ndarray):
# tuplesafe
uniques = Index(uniques).values
llength = len(left)
labels = np.concatenate([left, right])
_, new_labels = sorting.safe_sort(uniques, labels, na_sentinel=-1)
new_labels = ensure_int64(new_labels)
new_left, new_right = new_labels[:llength], new_labels[llength:]
return new_left, new_right
def _get_join_keys(llab, rlab, shape, sort):
# how many levels can be done without overflow
pred = lambda i: not is_int64_overflow_possible(shape[:i])
nlev = next(filter(pred, range(len(shape), 0, -1)))
# get keys for the first `nlev` levels
stride = np.prod(shape[1:nlev], dtype="i8")
lkey = stride * llab[0].astype("i8", subok=False, copy=False)
rkey = stride * rlab[0].astype("i8", subok=False, copy=False)
for i in range(1, nlev):
with np.errstate(divide="ignore"):
stride //= shape[i]
lkey += llab[i] * stride
rkey += rlab[i] * stride
if nlev == len(shape): # all done!
return lkey, rkey
# densify current keys to avoid overflow
lkey, rkey, count = _factorize_keys(lkey, rkey, sort=sort)
llab = [lkey] + llab[nlev:]
rlab = [rkey] + rlab[nlev:]
shape = [count] + shape[nlev:]
return _get_join_keys(llab, rlab, shape, sort)
def _should_fill(lname, rname):
if not isinstance(lname, str) or not isinstance(rname, str):
return True
return lname == rname
def _any(x):
return x is not None and com.any_not_none(*x)
def validate_operand(obj):
if isinstance(obj, DataFrame):
return obj
elif isinstance(obj, Series):
if obj.name is None:
raise ValueError("Cannot merge a Series without a name")
else:
return obj.to_frame()
else:
raise TypeError(
"Can only merge Series or DataFrame objects, "
"a {obj} was passed".format(obj=type(obj))
)
def _items_overlap_with_suffix(left, lsuffix, right, rsuffix):
"""
If two indices overlap, add suffixes to overlapping entries.
If corresponding suffix is empty, the entry is simply converted to string.
"""
to_rename = left.intersection(right)
if len(to_rename) == 0:
return left, right
if not lsuffix and not rsuffix:
raise ValueError(
"columns overlap but no suffix specified: "
"{rename}".format(rename=to_rename)
)
def renamer(x, suffix):
"""
Rename the left and right indices.
If there is overlap, and suffix is not None, add
suffix, otherwise, leave it as-is.
Parameters
----------
x : original column name
suffix : str or None
Returns
-------
x : renamed column name
"""
if x in to_rename and suffix is not None:
return "{x}{suffix}".format(x=x, suffix=suffix)
return x
lrenamer = partial(renamer, suffix=lsuffix)
rrenamer = partial(renamer, suffix=rsuffix)
return (_transform_index(left, lrenamer), _transform_index(right, rrenamer))
"""
SQL-style merge routines
"""
import copy
import datetime
from functools import partial
import string
import warnings
import numpy as np
from pandas._libs import hashtable as libhashtable, lib
import pandas._libs.join as libjoin
from pandas.errors import MergeError
from pandas.util._decorators import Appender, Substitution
from pandas.core.dtypes.common import (
ensure_float64,
ensure_int64,
ensure_object,
is_array_like,
is_bool,
is_bool_dtype,
is_categorical_dtype,
is_datetime64tz_dtype,
is_datetimelike,
is_dtype_equal,
is_extension_array_dtype,
is_float_dtype,
is_integer,
is_integer_dtype,
is_list_like,
is_number,
is_numeric_dtype,
is_object_dtype,
needs_i8_conversion,
)
from pandas.core.dtypes.missing import isnull, na_value_for_dtype
from pandas import Categorical, DataFrame, Index, MultiIndex, Series, Timedelta
import pandas.core.algorithms as algos
from pandas.core.arrays.categorical import _recode_for_categories
import pandas.core.common as com
from pandas.core.frame import _merge_doc
from pandas.core.internals import _transform_index, concatenate_block_managers
import pandas.core.sorting as sorting
from pandas.core.sorting import is_int64_overflow_possible
@Substitution("\nleft : DataFrame")
@Appender(_merge_doc, indents=0)
def merge(
left,
right,
how="inner",
on=None,
left_on=None,
right_on=None,
left_index=False,
right_index=False,
sort=False,
suffixes=("_x", "_y"),
copy=True,
indicator=False,
validate=None,
):
op = _MergeOperation(
left,
right,
how=how,
on=on,
left_on=left_on,
right_on=right_on,
left_index=left_index,
right_index=right_index,
sort=sort,
suffixes=suffixes,
copy=copy,
indicator=indicator,
validate=validate,
)
return op.get_result()
if __debug__:
merge.__doc__ = _merge_doc % "\nleft : DataFrame"
def _groupby_and_merge(by, on, left, right, _merge_pieces, check_duplicates=True):
"""
groupby & merge; we are always performing a left-by type operation
Parameters
----------
by: field to group
on: duplicates field
left: left frame
right: right frame
_merge_pieces: function for merging
check_duplicates: bool, default True
should we check & clean duplicates
"""
pieces = []
if not isinstance(by, (list, tuple)):
by = [by]
lby = left.groupby(by, sort=False)
# if we can groupby the rhs
# then we can get vastly better perf
try:
# we will check & remove duplicates if indicated
if check_duplicates:
if on is None:
on = []
elif not isinstance(on, (list, tuple)):
on = [on]
if right.duplicated(by + on).any():
right = right.drop_duplicates(by + on, keep="last")
rby = right.groupby(by, sort=False)
except KeyError:
rby = None
for key, lhs in lby:
if rby is None:
rhs = right
else:
try:
rhs = right.take(rby.indices[key])
except KeyError:
# key doesn't exist in left
lcols = lhs.columns.tolist()
cols = lcols + [r for r in right.columns if r not in set(lcols)]
merged = lhs.reindex(columns=cols)
merged.index = range(len(merged))
pieces.append(merged)
continue
merged = _merge_pieces(lhs, rhs)
# make sure join keys are in the merged
# TODO, should _merge_pieces do this?
for k in by:
try:
if k in merged:
merged[k] = key
except KeyError:
pass
pieces.append(merged)
# preserve the original order
# if we have a missing piece this can be reset
from pandas.core.reshape.concat import concat
result = concat(pieces, ignore_index=True)
result = result.reindex(columns=pieces[0].columns, copy=False)
return result, lby
def merge_ordered(
left,
right,
on=None,
left_on=None,
right_on=None,
left_by=None,
right_by=None,
fill_method=None,
suffixes=("_x", "_y"),
how="outer",
):
"""
Perform merge with optional filling/interpolation designed for ordered
data like time series data. Optionally perform group-wise merge (see
examples).
Parameters
----------
left : DataFrame
right : DataFrame
on : label or list
Field names to join on. Must be found in both DataFrames.
left_on : label or list, or array-like
Field names to join on in left DataFrame. Can be a vector or list of
vectors of the length of the DataFrame to use a particular vector as
the join key instead of columns
right_on : label or list, or array-like
Field names to join on in right DataFrame or vector/list of vectors per
left_on docs
left_by : column name or list of column names
Group left DataFrame by group columns and merge piece by piece with
right DataFrame
right_by : column name or list of column names
Group right DataFrame by group columns and merge piece by piece with
left DataFrame
fill_method : {'ffill', None}, default None
Interpolation method for data
suffixes : Sequence, default is ("_x", "_y")
A length-2 sequence where each element is optionally a string
indicating the suffix to add to overlapping column names in
`left` and `right` respectively. Pass a value of `None` instead
of a string to indicate that the column name from `left` or
`right` should be left as-is, with no suffix. At least one of the
values must not be None.
.. versionchanged:: 0.25.0
how : {'left', 'right', 'outer', 'inner'}, default 'outer'
* left: use only keys from left frame (SQL: left outer join)
* right: use only keys from right frame (SQL: right outer join)
* outer: use union of keys from both frames (SQL: full outer join)
* inner: use intersection of keys from both frames (SQL: inner join)
Returns
-------
merged : DataFrame
The output type will the be same as 'left', if it is a subclass
of DataFrame.
See Also
--------
merge
merge_asof
Examples
--------
>>> A >>> B
key lvalue group key rvalue
0 a 1 a 0 b 1
1 c 2 a 1 c 2
2 e 3 a 2 d 3
3 a 1 b
4 c 2 b
5 e 3 b
>>> merge_ordered(A, B, fill_method='ffill', left_by='group')
group key lvalue rvalue
0 a a 1 NaN
1 a b 1 1.0
2 a c 2 2.0
3 a d 2 3.0
4 a e 3 3.0
5 b a 1 NaN
6 b b 1 1.0
7 b c 2 2.0
8 b d 2 3.0
9 b e 3 3.0
"""
def _merger(x, y):
# perform the ordered merge operation
op = _OrderedMerge(
x,
y,
on=on,
left_on=left_on,
right_on=right_on,
suffixes=suffixes,
fill_method=fill_method,
how=how,
)
return op.get_result()
if left_by is not None and right_by is not None:
raise ValueError("Can only group either left or right frames")
elif left_by is not None:
result, _ = _groupby_and_merge(
left_by, on, left, right, lambda x, y: _merger(x, y), check_duplicates=False
)
elif right_by is not None:
result, _ = _groupby_and_merge(
right_by,
on,
right,
left,
lambda x, y: _merger(y, x),
check_duplicates=False,
)
else:
result = _merger(left, right)
return result
def merge_asof(
left,
right,
on=None,
left_on=None,
right_on=None,
left_index=False,
right_index=False,
by=None,
left_by=None,
right_by=None,
suffixes=("_x", "_y"),
tolerance=None,
allow_exact_matches=True,
direction="backward",
):
"""
Perform an asof merge. This is similar to a left-join except that we
match on nearest key rather than equal keys.
Both DataFrames must be sorted by the key.
For each row in the left DataFrame:
- A "backward" search selects the last row in the right DataFrame whose
'on' key is less than or equal to the left's key.
- A "forward" search selects the first row in the right DataFrame whose
'on' key is greater than or equal to the left's key.
- A "nearest" search selects the row in the right DataFrame whose 'on'
key is closest in absolute distance to the left's key.
The default is "backward" and is compatible in versions below 0.20.0.
The direction parameter was added in version 0.20.0 and introduces
"forward" and "nearest".
Optionally match on equivalent keys with 'by' before searching with 'on'.
Parameters
----------
left : DataFrame
right : DataFrame
on : label
Field name to join on. Must be found in both DataFrames.
The data MUST be ordered. Furthermore this must be a numeric column,
such as datetimelike, integer, or float. On or left_on/right_on
must be given.
left_on : label
Field name to join on in left DataFrame.
right_on : label
Field name to join on in right DataFrame.
left_index : bool
Use the index of the left DataFrame as the join key.
right_index : bool
Use the index of the right DataFrame as the join key.
by : column name or list of column names
Match on these columns before performing merge operation.
left_by : column name
Field names to match on in the left DataFrame.
right_by : column name
Field names to match on in the right DataFrame.
suffixes : 2-length sequence (tuple, list, ...)
Suffix to apply to overlapping column names in the left and right
side, respectively.
tolerance : int or Timedelta, optional, default None
Select asof tolerance within this range; must be compatible
with the merge index.
allow_exact_matches : bool, default True
- If True, allow matching with the same 'on' value
(i.e. less-than-or-equal-to / greater-than-or-equal-to)
- If False, don't match the same 'on' value
(i.e., strictly less-than / strictly greater-than)
direction : 'backward' (default), 'forward', or 'nearest'
Whether to search for prior, subsequent, or closest matches.
.. versionadded:: 0.20.0
Returns
-------
merged : DataFrame
See Also
--------
merge
merge_ordered
Examples
--------
>>> left = pd.DataFrame({'a': [1, 5, 10], 'left_val': ['a', 'b', 'c']})
>>> left
a left_val
0 1 a
1 5 b
2 10 c
>>> right = pd.DataFrame({'a': [1, 2, 3, 6, 7],
... 'right_val': [1, 2, 3, 6, 7]})
>>> right
a right_val
0 1 1
1 2 2
2 3 3
3 6 6
4 7 7
>>> pd.merge_asof(left, right, on='a')
a left_val right_val
0 1 a 1
1 5 b 3
2 10 c 7
>>> pd.merge_asof(left, right, on='a', allow_exact_matches=False)
a left_val right_val
0 1 a NaN
1 5 b 3.0
2 10 c 7.0
>>> pd.merge_asof(left, right, on='a', direction='forward')
a left_val right_val
0 1 a 1.0
1 5 b 6.0
2 10 c NaN
>>> pd.merge_asof(left, right, on='a', direction='nearest')
a left_val right_val
0 1 a 1
1 5 b 6
2 10 c 7
We can use indexed DataFrames as well.
>>> left = pd.DataFrame({'left_val': ['a', 'b', 'c']}, index=[1, 5, 10])
>>> left
left_val
1 a
5 b
10 c
>>> right = pd.DataFrame({'right_val': [1, 2, 3, 6, 7]},
... index=[1, 2, 3, 6, 7])
>>> right
right_val
1 1
2 2
3 3
6 6
7 7
>>> pd.merge_asof(left, right, left_index=True, right_index=True)
left_val right_val
1 a 1
5 b 3
10 c 7
Here is a real-world times-series example
>>> quotes
time ticker bid ask
0 2016-05-25 13:30:00.023 GOOG 720.50 720.93
1 2016-05-25 13:30:00.023 MSFT 51.95 51.96
2 2016-05-25 13:30:00.030 MSFT 51.97 51.98
3 2016-05-25 13:30:00.041 MSFT 51.99 52.00
4 2016-05-25 13:30:00.048 GOOG 720.50 720.93
5 2016-05-25 13:30:00.049 AAPL 97.99 98.01
6 2016-05-25 13:30:00.072 GOOG 720.50 720.88
7 2016-05-25 13:30:00.075 MSFT 52.01 52.03
>>> trades
time ticker price quantity
0 2016-05-25 13:30:00.023 MSFT 51.95 75
1 2016-05-25 13:30:00.038 MSFT 51.95 155
2 2016-05-25 13:30:00.048 GOOG 720.77 100
3 2016-05-25 13:30:00.048 GOOG 720.92 100
4 2016-05-25 13:30:00.048 AAPL 98.00 100
By default we are taking the asof of the quotes
>>> pd.merge_asof(trades, quotes,
... on='time',
... by='ticker')
time ticker price quantity bid ask
0 2016-05-25 13:30:00.023 MSFT 51.95 75 51.95 51.96
1 2016-05-25 13:30:00.038 MSFT 51.95 155 51.97 51.98
2 2016-05-25 13:30:00.048 GOOG 720.77 100 720.50 720.93
3 2016-05-25 13:30:00.048 GOOG 720.92 100 720.50 720.93
4 2016-05-25 13:30:00.048 AAPL 98.00 100 NaN NaN
We only asof within 2ms between the quote time and the trade time
>>> pd.merge_asof(trades, quotes,
... on='time',
... by='ticker',
... tolerance=pd.Timedelta('2ms'))
time ticker price quantity bid ask
0 2016-05-25 13:30:00.023 MSFT 51.95 75 51.95 51.96
1 2016-05-25 13:30:00.038 MSFT 51.95 155 NaN NaN
2 2016-05-25 13:30:00.048 GOOG 720.77 100 720.50 720.93
3 2016-05-25 13:30:00.048 GOOG 720.92 100 720.50 720.93
4 2016-05-25 13:30:00.048 AAPL 98.00 100 NaN NaN
We only asof within 10ms between the quote time and the trade time
and we exclude exact matches on time. However *prior* data will
propagate forward
>>> pd.merge_asof(trades, quotes,
... on='time',
... by='ticker',
... tolerance=pd.Timedelta('10ms'),
... allow_exact_matches=False)
time ticker price quantity bid ask
0 2016-05-25 13:30:00.023 MSFT 51.95 75 NaN NaN
1 2016-05-25 13:30:00.038 MSFT 51.95 155 51.97 51.98
2 2016-05-25 13:30:00.048 GOOG 720.77 100 NaN NaN
3 2016-05-25 13:30:00.048 GOOG 720.92 100 NaN NaN
4 2016-05-25 13:30:00.048 AAPL 98.00 100 NaN NaN
"""
op = _AsOfMerge(
left,
right,
on=on,
left_on=left_on,
right_on=right_on,
left_index=left_index,
right_index=right_index,
by=by,
left_by=left_by,
right_by=right_by,
suffixes=suffixes,
how="asof",
tolerance=tolerance,
allow_exact_matches=allow_exact_matches,
direction=direction,
)
return op.get_result()
# TODO: transformations??
# TODO: only copy DataFrames when modification necessary
class _MergeOperation:
"""
Perform a database (SQL) merge operation between two DataFrame objects
using either columns as keys or their row indexes
"""
_merge_type = "merge"
def __init__(
self,
left,
right,
how="inner",
on=None,
left_on=None,
right_on=None,
axis=1,
left_index=False,
right_index=False,
sort=True,
suffixes=("_x", "_y"),
copy=True,
indicator=False,
validate=None,
):
left = validate_operand(left)
right = validate_operand(right)
self.left = self.orig_left = left
self.right = self.orig_right = right
self.how = how
self.axis = axis
self.on = com.maybe_make_list(on)
self.left_on = com.maybe_make_list(left_on)
self.right_on = com.maybe_make_list(right_on)
self.copy = copy
self.suffixes = suffixes
self.sort = sort
self.left_index = left_index
self.right_index = right_index
self.indicator = indicator
if isinstance(self.indicator, str):
self.indicator_name = self.indicator
elif isinstance(self.indicator, bool):
self.indicator_name = "_merge" if self.indicator else None
else:
raise ValueError(
"indicator option can only accept boolean or string arguments"
)
if not is_bool(left_index):
raise ValueError(
"left_index parameter must be of type bool, not "
"{left_index}".format(left_index=type(left_index))
)
if not is_bool(right_index):
raise ValueError(
"right_index parameter must be of type bool, not "
"{right_index}".format(right_index=type(right_index))
)
# warn user when merging between different levels
if left.columns.nlevels != right.columns.nlevels:
msg = (
"merging between different levels can give an unintended "
"result ({left} levels on the left, {right} on the right)"
).format(left=left.columns.nlevels, right=right.columns.nlevels)
warnings.warn(msg, UserWarning)
self._validate_specification()
# note this function has side effects
(
self.left_join_keys,
self.right_join_keys,
self.join_names,
) = self._get_merge_keys()
# validate the merge keys dtypes. We may need to coerce
# to avoid incompat dtypes
self._maybe_coerce_merge_keys()
# If argument passed to validate,
# check if columns specified as unique
# are in fact unique.
if validate is not None:
self._validate(validate)
def get_result(self):
if self.indicator:
self.left, self.right = self._indicator_pre_merge(self.left, self.right)
join_index, left_indexer, right_indexer = self._get_join_info()
ldata, rdata = self.left._data, self.right._data
lsuf, rsuf = self.suffixes
llabels, rlabels = _items_overlap_with_suffix(
ldata.items, lsuf, rdata.items, rsuf
)
lindexers = {1: left_indexer} if left_indexer is not None else {}
rindexers = {1: right_indexer} if right_indexer is not None else {}
result_data = concatenate_block_managers(
[(ldata, lindexers), (rdata, rindexers)],
axes=[llabels.append(rlabels), join_index],
concat_axis=0,
copy=self.copy,
)
typ = self.left._constructor
result = typ(result_data).__finalize__(self, method=self._merge_type)
if self.indicator:
result = self._indicator_post_merge(result)
self._maybe_add_join_keys(result, left_indexer, right_indexer)
self._maybe_restore_index_levels(result)
return result
def _indicator_pre_merge(self, left, right):
columns = left.columns.union(right.columns)
for i in ["_left_indicator", "_right_indicator"]:
if i in columns:
raise ValueError(
"Cannot use `indicator=True` option when "
"data contains a column named {name}".format(name=i)
)
if self.indicator_name in columns:
raise ValueError(
"Cannot use name of an existing column for indicator column"
)
left = left.copy()
right = right.copy()
left["_left_indicator"] = 1
left["_left_indicator"] = left["_left_indicator"].astype("int8")
right["_right_indicator"] = 2
right["_right_indicator"] = right["_right_indicator"].astype("int8")
return left, right
def _indicator_post_merge(self, result):
result["_left_indicator"] = result["_left_indicator"].fillna(0)
result["_right_indicator"] = result["_right_indicator"].fillna(0)
result[self.indicator_name] = Categorical(
(result["_left_indicator"] + result["_right_indicator"]),
categories=[1, 2, 3],
)
result[self.indicator_name] = result[self.indicator_name].cat.rename_categories(
["left_only", "right_only", "both"]
)
result = result.drop(labels=["_left_indicator", "_right_indicator"], axis=1)
return result
def _maybe_restore_index_levels(self, result):
"""
Restore index levels specified as `on` parameters
Here we check for cases where `self.left_on` and `self.right_on` pairs
each reference an index level in their respective DataFrames. The
joined columns corresponding to these pairs are then restored to the
index of `result`.
**Note:** This method has side effects. It modifies `result` in-place
Parameters
----------
result: DataFrame
merge result
Returns
-------
None
"""
names_to_restore = []
for name, left_key, right_key in zip(
self.join_names, self.left_on, self.right_on
):
if (
self.orig_left._is_level_reference(left_key)
and self.orig_right._is_level_reference(right_key)
and name not in result.index.names
):
names_to_restore.append(name)
if names_to_restore:
result.set_index(names_to_restore, inplace=True)
def _maybe_add_join_keys(self, result, left_indexer, right_indexer):
left_has_missing = None
right_has_missing = None
keys = zip(self.join_names, self.left_on, self.right_on)
for i, (name, lname, rname) in enumerate(keys):
if not _should_fill(lname, rname):
continue
take_left, take_right = None, None
if name in result:
if left_indexer is not None and right_indexer is not None:
if name in self.left:
if left_has_missing is None:
left_has_missing = (left_indexer == -1).any()
if left_has_missing:
take_right = self.right_join_keys[i]
if not is_dtype_equal(
result[name].dtype, self.left[name].dtype
):
take_left = self.left[name]._values
elif name in self.right:
if right_has_missing is None:
right_has_missing = (right_indexer == -1).any()
if right_has_missing:
take_left = self.left_join_keys[i]
if not is_dtype_equal(
result[name].dtype, self.right[name].dtype
):
take_right = self.right[name]._values
elif left_indexer is not None and is_array_like(self.left_join_keys[i]):
take_left = self.left_join_keys[i]
take_right = self.right_join_keys[i]
if take_left is not None or take_right is not None:
if take_left is None:
lvals = result[name]._values
else:
lfill = na_value_for_dtype(take_left.dtype)
lvals = algos.take_1d(take_left, left_indexer, fill_value=lfill)
if take_right is None:
rvals = result[name]._values
else:
rfill = na_value_for_dtype(take_right.dtype)
rvals = algos.take_1d(take_right, right_indexer, fill_value=rfill)
# if we have an all missing left_indexer
# make sure to just use the right values
mask = left_indexer == -1
if mask.all():
key_col = rvals
else:
key_col = Index(lvals).where(~mask, rvals)
if result._is_label_reference(name):
result[name] = key_col
elif result._is_level_reference(name):
if isinstance(result.index, MultiIndex):
key_col.name = name
idx_list = [
result.index.get_level_values(level_name)
if level_name != name
else key_col
for level_name in result.index.names
]
result.set_index(idx_list, inplace=True)
else:
result.index = Index(key_col, name=name)
else:
result.insert(i, name or "key_{i}".format(i=i), key_col)
def _get_join_indexers(self):
""" return the join indexers """
return _get_join_indexers(
self.left_join_keys, self.right_join_keys, sort=self.sort, how=self.how
)
def _get_join_info(self):
left_ax = self.left._data.axes[self.axis]
right_ax = self.right._data.axes[self.axis]
if self.left_index and self.right_index and self.how != "asof":
join_index, left_indexer, right_indexer = left_ax.join(
right_ax, how=self.how, return_indexers=True, sort=self.sort
)
elif self.right_index and self.how == "left":
join_index, left_indexer, right_indexer = _left_join_on_index(
left_ax, right_ax, self.left_join_keys, sort=self.sort
)
elif self.left_index and self.how == "right":
join_index, right_indexer, left_indexer = _left_join_on_index(
right_ax, left_ax, self.right_join_keys, sort=self.sort
)
else:
(left_indexer, right_indexer) = self._get_join_indexers()
if self.right_index:
if len(self.left) > 0:
join_index = self._create_join_index(
self.left.index,
self.right.index,
left_indexer,
right_indexer,
how="right",
)
else:
join_index = self.right.index.take(right_indexer)
left_indexer = np.array([-1] * len(join_index))
elif self.left_index:
if len(self.right) > 0:
join_index = self._create_join_index(
self.right.index,
self.left.index,
right_indexer,
left_indexer,
how="left",
)
else:
join_index = self.left.index.take(left_indexer)
right_indexer = np.array([-1] * len(join_index))
else:
join_index = Index(np.arange(len(left_indexer)))
if len(join_index) == 0:
join_index = join_index.astype(object)
return join_index, left_indexer, right_indexer
def _create_join_index(
self, index, other_index, indexer, other_indexer, how="left"
):
"""
Create a join index by rearranging one index to match another
Parameters
----------
index: Index being rearranged
other_index: Index used to supply values not found in index
indexer: how to rearrange index
how: replacement is only necessary if indexer based on other_index
Returns
-------
join_index
"""
if self.how in (how, "outer") and not isinstance(other_index, MultiIndex):
# if final index requires values in other_index but not target
# index, indexer may hold missing (-1) values, causing Index.take
# to take the final value in target index. So, we set the last
# element to be the desired fill value. We do not use allow_fill
# and fill_value because it throws a ValueError on integer indices
mask = indexer == -1
if np.any(mask):
fill_value = na_value_for_dtype(index.dtype, compat=False)
index = index.append(Index([fill_value]))
return index.take(indexer)
def _get_merge_keys(self):
"""
Note: has side effects (copy/delete key columns)
Parameters
----------
left
right
on
Returns
-------
left_keys, right_keys
"""
left_keys = []
right_keys = []
join_names = []
right_drop = []
left_drop = []
left, right = self.left, self.right
is_lkey = lambda x: is_array_like(x) and len(x) == len(left)
is_rkey = lambda x: is_array_like(x) and len(x) == len(right)
# Note that pd.merge_asof() has separate 'on' and 'by' parameters. A
# user could, for example, request 'left_index' and 'left_by'. In a
# regular pd.merge(), users cannot specify both 'left_index' and
# 'left_on'. (Instead, users have a MultiIndex). That means the
# self.left_on in this function is always empty in a pd.merge(), but
# a pd.merge_asof(left_index=True, left_by=...) will result in a
# self.left_on array with a None in the middle of it. This requires
# a work-around as designated in the code below.
# See _validate_specification() for where this happens.
# ugh, spaghetti re #733
if _any(self.left_on) and _any(self.right_on):
for lk, rk in zip(self.left_on, self.right_on):
if is_lkey(lk):
left_keys.append(lk)
if is_rkey(rk):
right_keys.append(rk)
join_names.append(None) # what to do?
else:
if rk is not None:
right_keys.append(right._get_label_or_level_values(rk))
join_names.append(rk)
else:
# work-around for merge_asof(right_index=True)
right_keys.append(right.index)
join_names.append(right.index.name)
else:
if not is_rkey(rk):
if rk is not None:
right_keys.append(right._get_label_or_level_values(rk))
else:
# work-around for merge_asof(right_index=True)
right_keys.append(right.index)
if lk is not None and lk == rk:
# avoid key upcast in corner case (length-0)
if len(left) > 0:
right_drop.append(rk)
else:
left_drop.append(lk)
else:
right_keys.append(rk)
if lk is not None:
left_keys.append(left._get_label_or_level_values(lk))
join_names.append(lk)
else:
# work-around for merge_asof(left_index=True)
left_keys.append(left.index)
join_names.append(left.index.name)
elif _any(self.left_on):
for k in self.left_on:
if is_lkey(k):
left_keys.append(k)
join_names.append(None)
else:
left_keys.append(left._get_label_or_level_values(k))
join_names.append(k)
if isinstance(self.right.index, MultiIndex):
right_keys = [
lev._values.take(lev_codes)
for lev, lev_codes in zip(
self.right.index.levels, self.right.index.codes
)
]
else:
right_keys = [self.right.index._values]
elif _any(self.right_on):
for k in self.right_on:
if is_rkey(k):
right_keys.append(k)
join_names.append(None)
else:
right_keys.append(right._get_label_or_level_values(k))
join_names.append(k)
if isinstance(self.left.index, MultiIndex):
left_keys = [
lev._values.take(lev_codes)
for lev, lev_codes in zip(
self.left.index.levels, self.left.index.codes
)
]
else:
left_keys = [self.left.index.values]
if left_drop:
self.left = self.left._drop_labels_or_levels(left_drop)
if right_drop:
self.right = self.right._drop_labels_or_levels(right_drop)
return left_keys, right_keys, join_names
def _maybe_coerce_merge_keys(self):
# we have valid mergees but we may have to further
# coerce these if they are originally incompatible types
#
# for example if these are categorical, but are not dtype_equal
# or if we have object and integer dtypes
for lk, rk, name in zip(
self.left_join_keys, self.right_join_keys, self.join_names
):
if (len(lk) and not len(rk)) or (not len(lk) and len(rk)):
continue
lk_is_cat = is_categorical_dtype(lk)
rk_is_cat = is_categorical_dtype(rk)
lk_is_object = is_object_dtype(lk)
rk_is_object = is_object_dtype(rk)
# if either left or right is a categorical
# then the must match exactly in categories & ordered
if lk_is_cat and rk_is_cat:
if lk.is_dtype_equal(rk):
continue
elif lk_is_cat or rk_is_cat:
pass
elif is_dtype_equal(lk.dtype, rk.dtype):
continue
msg = (
"You are trying to merge on {lk_dtype} and "
"{rk_dtype} columns. If you wish to proceed "
"you should use pd.concat".format(lk_dtype=lk.dtype, rk_dtype=rk.dtype)
)
# if we are numeric, then allow differing
# kinds to proceed, eg. int64 and int8, int and float
# further if we are object, but we infer to
# the same, then proceed
if is_numeric_dtype(lk) and is_numeric_dtype(rk):
if lk.dtype.kind == rk.dtype.kind:
continue
# check whether ints and floats
elif is_integer_dtype(rk) and is_float_dtype(lk):
if not (lk == lk.astype(rk.dtype))[~np.isnan(lk)].all():
warnings.warn(
"You are merging on int and float "
"columns where the float values "
"are not equal to their int "
"representation",
UserWarning,
)
continue
elif is_float_dtype(rk) and is_integer_dtype(lk):
if not (rk == rk.astype(lk.dtype))[~np.isnan(rk)].all():
warnings.warn(
"You are merging on int and float "
"columns where the float values "
"are not equal to their int "
"representation",
UserWarning,
)
continue
# let's infer and see if we are ok
elif lib.infer_dtype(lk, skipna=False) == lib.infer_dtype(
rk, skipna=False
):
continue
# Check if we are trying to merge on obviously
# incompatible dtypes GH 9780, GH 15800
# bool values are coerced to object
elif (lk_is_object and is_bool_dtype(rk)) or (
is_bool_dtype(lk) and rk_is_object
):
pass
# object values are allowed to be merged
elif (lk_is_object and is_numeric_dtype(rk)) or (
is_numeric_dtype(lk) and rk_is_object
):
inferred_left = lib.infer_dtype(lk, skipna=False)
inferred_right = lib.infer_dtype(rk, skipna=False)
bool_types = ["integer", "mixed-integer", "boolean", "empty"]
string_types = ["string", "unicode", "mixed", "bytes", "empty"]
# inferred bool
if inferred_left in bool_types and inferred_right in bool_types:
pass
# unless we are merging non-string-like with string-like
elif (
inferred_left in string_types and inferred_right not in string_types
) or (
inferred_right in string_types and inferred_left not in string_types
):
raise ValueError(msg)
# datetimelikes must match exactly
elif is_datetimelike(lk) and not is_datetimelike(rk):
raise ValueError(msg)
elif not is_datetimelike(lk) and is_datetimelike(rk):
raise ValueError(msg)
elif is_datetime64tz_dtype(lk) and not is_datetime64tz_dtype(rk):
raise ValueError(msg)
elif not is_datetime64tz_dtype(lk) and is_datetime64tz_dtype(rk):
raise ValueError(msg)
elif lk_is_object and rk_is_object:
continue
# Houston, we have a problem!
# let's coerce to object if the dtypes aren't
# categorical, otherwise coerce to the category
# dtype. If we coerced categories to object,
# then we would lose type information on some
# columns, and end up trying to merge
# incompatible dtypes. See GH 16900.
if name in self.left.columns:
typ = lk.categories.dtype if lk_is_cat else object
self.left = self.left.assign(**{name: self.left[name].astype(typ)})
if name in self.right.columns:
typ = rk.categories.dtype if rk_is_cat else object
self.right = self.right.assign(**{name: self.right[name].astype(typ)})
def _validate_specification(self):
# Hm, any way to make this logic less complicated??
if self.on is None and self.left_on is None and self.right_on is None:
if self.left_index and self.right_index:
self.left_on, self.right_on = (), ()
elif self.left_index:
if self.right_on is None:
raise MergeError("Must pass right_on or right_index=True")
elif self.right_index:
if self.left_on is None:
raise MergeError("Must pass left_on or left_index=True")
else:
# use the common columns
common_cols = self.left.columns.intersection(self.right.columns)
if len(common_cols) == 0:
raise MergeError(
"No common columns to perform merge on. "
"Merge options: left_on={lon}, right_on={ron}, "
"left_index={lidx}, right_index={ridx}".format(
lon=self.left_on,
ron=self.right_on,
lidx=self.left_index,
ridx=self.right_index,
)
)
if not common_cols.is_unique:
raise MergeError(
"Data columns not unique: {common!r}".format(common=common_cols)
)
self.left_on = self.right_on = common_cols
elif self.on is not None:
if self.left_on is not None or self.right_on is not None:
raise MergeError(
'Can only pass argument "on" OR "left_on" '
'and "right_on", not a combination of both.'
)
self.left_on = self.right_on = self.on
elif self.left_on is not None:
n = len(self.left_on)
if self.right_index:
if len(self.left_on) != self.right.index.nlevels:
raise ValueError(
"len(left_on) must equal the number "
'of levels in the index of "right"'
)
self.right_on = [None] * n
elif self.right_on is not None:
n = len(self.right_on)
if self.left_index:
if len(self.right_on) != self.left.index.nlevels:
raise ValueError(
"len(right_on) must equal the number "
'of levels in the index of "left"'
)
self.left_on = [None] * n
if len(self.right_on) != len(self.left_on):
raise ValueError("len(right_on) must equal len(left_on)")
def _validate(self, validate):
# Check uniqueness of each
if self.left_index:
left_unique = self.orig_left.index.is_unique
else:
left_unique = MultiIndex.from_arrays(self.left_join_keys).is_unique
if self.right_index:
right_unique = self.orig_right.index.is_unique
else:
right_unique = MultiIndex.from_arrays(self.right_join_keys).is_unique
# Check data integrity
if validate in ["one_to_one", "1:1"]:
if not left_unique and not right_unique:
raise MergeError(
"Merge keys are not unique in either left"
" or right dataset; not a one-to-one merge"
)
elif not left_unique:
raise MergeError(
"Merge keys are not unique in left dataset;"
" not a one-to-one merge"
)
elif not right_unique:
raise MergeError(
"Merge keys are not unique in right dataset;"
" not a one-to-one merge"
)
elif validate in ["one_to_many", "1:m"]:
if not left_unique:
raise MergeError(
"Merge keys are not unique in left dataset;"
" not a one-to-many merge"
)
elif validate in ["many_to_one", "m:1"]:
if not right_unique:
raise MergeError(
"Merge keys are not unique in right dataset;"
" not a many-to-one merge"
)
elif validate in ["many_to_many", "m:m"]:
pass
else:
raise ValueError("Not a valid argument for validate")
def _get_join_indexers(left_keys, right_keys, sort=False, how="inner", **kwargs):
"""
Parameters
----------
left_keys: ndarray, Index, Series
right_keys: ndarray, Index, Series
sort: bool, default False
how: string {'inner', 'outer', 'left', 'right'}, default 'inner'
Returns
-------
tuple of (left_indexer, right_indexer)
indexers into the left_keys, right_keys
"""
assert len(left_keys) == len(
right_keys
), "left_key and right_keys must be the same length"
# bind `sort` arg. of _factorize_keys
fkeys = partial(_factorize_keys, sort=sort)
# get left & right join labels and num. of levels at each location
llab, rlab, shape = map(list, zip(*map(fkeys, left_keys, right_keys)))
# get flat i8 keys from label lists
lkey, rkey = _get_join_keys(llab, rlab, shape, sort)
# factorize keys to a dense i8 space
# `count` is the num. of unique keys
# set(lkey) | set(rkey) == range(count)
lkey, rkey, count = fkeys(lkey, rkey)
# preserve left frame order if how == 'left' and sort == False
kwargs = copy.copy(kwargs)
if how == "left":
kwargs["sort"] = sort
join_func = _join_functions[how]
return join_func(lkey, rkey, count, **kwargs)
def _restore_dropped_levels_multijoin(
left, right, dropped_level_names, join_index, lindexer, rindexer
):
"""
*this is an internal non-public method*
Returns the levels, labels and names of a multi-index to multi-index join.
Depending on the type of join, this method restores the appropriate
dropped levels of the joined multi-index.
The method relies on lidx, rindexer which hold the index positions of
left and right, where a join was feasible
Parameters
----------
left : MultiIndex
left index
right : MultiIndex
right index
dropped_level_names : str array
list of non-common level names
join_index : MultiIndex
the index of the join between the
common levels of left and right
lindexer : intp array
left indexer
rindexer : intp array
right indexer
Returns
-------
levels : list of Index
levels of combined multiindexes
labels : intp array
labels of combined multiindexes
names : str array
names of combined multiindexes
"""
def _convert_to_mulitindex(index):
if isinstance(index, MultiIndex):
return index
else:
return MultiIndex.from_arrays([index.values], names=[index.name])
# For multi-multi joins with one overlapping level,
# the returned index if of type Index
# Assure that join_index is of type MultiIndex
# so that dropped levels can be appended
join_index = _convert_to_mulitindex(join_index)
join_levels = join_index.levels
join_codes = join_index.codes
join_names = join_index.names
# lindexer and rindexer hold the indexes where the join occurred
# for left and right respectively. If left/right is None then
# the join occurred on all indices of left/right
if lindexer is None:
lindexer = range(left.size)
if rindexer is None:
rindexer = range(right.size)
# Iterate through the levels that must be restored
for dropped_level_name in dropped_level_names:
if dropped_level_name in left.names:
idx = left
indexer = lindexer
else:
idx = right
indexer = rindexer
# The index of the level name to be restored
name_idx = idx.names.index(dropped_level_name)
restore_levels = idx.levels[name_idx]
# Inject -1 in the codes list where a join was not possible
# IOW indexer[i]=-1
codes = idx.codes[name_idx]
restore_codes = algos.take_nd(codes, indexer, fill_value=-1)
join_levels = join_levels + [restore_levels]
join_codes = join_codes + [restore_codes]
join_names = join_names + [dropped_level_name]
return join_levels, join_codes, join_names
class _OrderedMerge(_MergeOperation):
_merge_type = "ordered_merge"
def __init__(
self,
left,
right,
on=None,
left_on=None,
right_on=None,
left_index=False,
right_index=False,
axis=1,
suffixes=("_x", "_y"),
copy=True,
fill_method=None,
how="outer",
):
self.fill_method = fill_method
_MergeOperation.__init__(
self,
left,
right,
on=on,
left_on=left_on,
left_index=left_index,
right_index=right_index,
right_on=right_on,
axis=axis,
how=how,
suffixes=suffixes,
sort=True, # factorize sorts
)
def get_result(self):
join_index, left_indexer, right_indexer = self._get_join_info()
# this is a bit kludgy
ldata, rdata = self.left._data, self.right._data
lsuf, rsuf = self.suffixes
llabels, rlabels = _items_overlap_with_suffix(
ldata.items, lsuf, rdata.items, rsuf
)
if self.fill_method == "ffill":
left_join_indexer = libjoin.ffill_indexer(left_indexer)
right_join_indexer = libjoin.ffill_indexer(right_indexer)
else:
left_join_indexer = left_indexer
right_join_indexer = right_indexer
lindexers = {1: left_join_indexer} if left_join_indexer is not None else {}
rindexers = {1: right_join_indexer} if right_join_indexer is not None else {}
result_data = concatenate_block_managers(
[(ldata, lindexers), (rdata, rindexers)],
axes=[llabels.append(rlabels), join_index],
concat_axis=0,
copy=self.copy,
)
typ = self.left._constructor
result = typ(result_data).__finalize__(self, method=self._merge_type)
self._maybe_add_join_keys(result, left_indexer, right_indexer)
return result
def _asof_function(direction):
name = "asof_join_{dir}".format(dir=direction)
return getattr(libjoin, name, None)
def _asof_by_function(direction):
name = "asof_join_{dir}_on_X_by_Y".format(dir=direction)
return getattr(libjoin, name, None)
_type_casters = {
"int64_t": ensure_int64,
"double": ensure_float64,
"object": ensure_object,
}
def _get_cython_type_upcast(dtype):
""" Upcast a dtype to 'int64_t', 'double', or 'object' """
if is_integer_dtype(dtype):
return "int64_t"
elif is_float_dtype(dtype):
return "double"
else:
return "object"
class _AsOfMerge(_OrderedMerge):
_merge_type = "asof_merge"
def __init__(
self,
left,
right,
on=None,
left_on=None,
right_on=None,
left_index=False,
right_index=False,
by=None,
left_by=None,
right_by=None,
axis=1,
suffixes=("_x", "_y"),
copy=True,
fill_method=None,
how="asof",
tolerance=None,
allow_exact_matches=True,
direction="backward",
):
self.by = by
self.left_by = left_by
self.right_by = right_by
self.tolerance = tolerance
self.allow_exact_matches = allow_exact_matches
self.direction = direction
_OrderedMerge.__init__(
self,
left,
right,
on=on,
left_on=left_on,
right_on=right_on,
left_index=left_index,
right_index=right_index,
axis=axis,
how=how,
suffixes=suffixes,
fill_method=fill_method,
)
def _validate_specification(self):
super()._validate_specification()
# we only allow on to be a single item for on
if len(self.left_on) != 1 and not self.left_index:
raise MergeError("can only asof on a key for left")
if len(self.right_on) != 1 and not self.right_index:
raise MergeError("can only asof on a key for right")
if self.left_index and isinstance(self.left.index, MultiIndex):
raise MergeError("left can only have one index")
if self.right_index and isinstance(self.right.index, MultiIndex):
raise MergeError("right can only have one index")
# set 'by' columns
if self.by is not None:
if self.left_by is not None or self.right_by is not None:
raise MergeError("Can only pass by OR left_by and right_by")
self.left_by = self.right_by = self.by
if self.left_by is None and self.right_by is not None:
raise MergeError("missing left_by")
if self.left_by is not None and self.right_by is None:
raise MergeError("missing right_by")
# add 'by' to our key-list so we can have it in the
# output as a key
if self.left_by is not None:
if not is_list_like(self.left_by):
self.left_by = [self.left_by]
if not is_list_like(self.right_by):
self.right_by = [self.right_by]
if len(self.left_by) != len(self.right_by):
raise MergeError("left_by and right_by must be same length")
self.left_on = self.left_by + list(self.left_on)
self.right_on = self.right_by + list(self.right_on)
# check 'direction' is valid
if self.direction not in ["backward", "forward", "nearest"]:
raise MergeError(
"direction invalid: {direction}".format(direction=self.direction)
)
@property
def _asof_key(self):
""" This is our asof key, the 'on' """
return self.left_on[-1]
def _get_merge_keys(self):
# note this function has side effects
(left_join_keys, right_join_keys, join_names) = super()._get_merge_keys()
# validate index types are the same
for i, (lk, rk) in enumerate(zip(left_join_keys, right_join_keys)):
if not is_dtype_equal(lk.dtype, rk.dtype):
if is_categorical_dtype(lk.dtype) and is_categorical_dtype(rk.dtype):
# The generic error message is confusing for categoricals.
#
# In this function, the join keys include both the original
# ones of the merge_asof() call, and also the keys passed
# to its by= argument. Unordered but equal categories
# are not supported for the former, but will fail
# later with a ValueError, so we don't *need* to check
# for them here.
msg = (
"incompatible merge keys [{i}] {lkdtype} and "
"{rkdtype}, both sides category, but not equal ones".format(
i=i, lkdtype=repr(lk.dtype), rkdtype=repr(rk.dtype)
)
)
else:
msg = (
"incompatible merge keys [{i}] {lkdtype} and "
"{rkdtype}, must be the same type".format(
i=i, lkdtype=repr(lk.dtype), rkdtype=repr(rk.dtype)
)
)
raise MergeError(msg)
# validate tolerance; datetime.timedelta or Timedelta if we have a DTI
if self.tolerance is not None:
if self.left_index:
lt = self.left.index
else:
lt = left_join_keys[-1]
msg = (
"incompatible tolerance {tolerance}, must be compat "
"with type {lkdtype}".format(
tolerance=type(self.tolerance), lkdtype=repr(lt.dtype)
)
)
if is_datetimelike(lt):
if not isinstance(self.tolerance, datetime.timedelta):
raise MergeError(msg)
if self.tolerance < Timedelta(0):
raise MergeError("tolerance must be positive")
elif is_integer_dtype(lt):
if not is_integer(self.tolerance):
raise MergeError(msg)
if self.tolerance < 0:
raise MergeError("tolerance must be positive")
elif is_float_dtype(lt):
if not is_number(self.tolerance):
raise MergeError(msg)
if self.tolerance < 0:
raise MergeError("tolerance must be positive")
else:
raise MergeError("key must be integer, timestamp or float")
# validate allow_exact_matches
if not is_bool(self.allow_exact_matches):
msg = "allow_exact_matches must be boolean, passed {passed}"
raise MergeError(msg.format(passed=self.allow_exact_matches))
return left_join_keys, right_join_keys, join_names
def _get_join_indexers(self):
""" return the join indexers """
def flip(xs):
""" unlike np.transpose, this returns an array of tuples """
xs = [
x if not is_extension_array_dtype(x) else x._ndarray_values for x in xs
]
labels = list(string.ascii_lowercase[: len(xs)])
dtypes = [x.dtype for x in xs]
labeled_dtypes = list(zip(labels, dtypes))
return np.array(list(zip(*xs)), labeled_dtypes)
# values to compare
left_values = (
self.left.index.values if self.left_index else self.left_join_keys[-1]
)
right_values = (
self.right.index.values if self.right_index else self.right_join_keys[-1]
)
tolerance = self.tolerance
# we require sortedness and non-null values in the join keys
msg_sorted = "{side} keys must be sorted"
msg_missings = "Merge keys contain null values on {side} side"
if not Index(left_values).is_monotonic:
if isnull(left_values).any():
raise ValueError(msg_missings.format(side="left"))
else:
raise ValueError(msg_sorted.format(side="left"))
if not Index(right_values).is_monotonic:
if isnull(right_values).any():
raise ValueError(msg_missings.format(side="right"))
else:
raise ValueError(msg_sorted.format(side="right"))
# initial type conversion as needed
if needs_i8_conversion(left_values):
left_values = left_values.view("i8")
right_values = right_values.view("i8")
if tolerance is not None:
tolerance = Timedelta(tolerance)
tolerance = tolerance.value
# a "by" parameter requires special handling
if self.left_by is not None:
# remove 'on' parameter from values if one existed
if self.left_index and self.right_index:
left_by_values = self.left_join_keys
right_by_values = self.right_join_keys
else:
left_by_values = self.left_join_keys[0:-1]
right_by_values = self.right_join_keys[0:-1]
# get tuple representation of values if more than one
if len(left_by_values) == 1:
left_by_values = left_by_values[0]
right_by_values = right_by_values[0]
else:
left_by_values = flip(left_by_values)
right_by_values = flip(right_by_values)
# upcast 'by' parameter because HashTable is limited
by_type = _get_cython_type_upcast(left_by_values.dtype)
by_type_caster = _type_casters[by_type]
left_by_values = by_type_caster(left_by_values)
right_by_values = by_type_caster(right_by_values)
# choose appropriate function by type
func = _asof_by_function(self.direction)
return func(
left_values,
right_values,
left_by_values,
right_by_values,
self.allow_exact_matches,
tolerance,
)
else:
# choose appropriate function by type
func = _asof_function(self.direction)
return func(left_values, right_values, self.allow_exact_matches, tolerance)
def _get_multiindex_indexer(join_keys, index, sort):
# bind `sort` argument
fkeys = partial(_factorize_keys, sort=sort)
# left & right join labels and num. of levels at each location
rcodes, lcodes, shape = map(list, zip(*map(fkeys, index.levels, join_keys)))
if sort:
rcodes = list(map(np.take, rcodes, index.codes))
else:
i8copy = lambda a: a.astype("i8", subok=False, copy=True)
rcodes = list(map(i8copy, index.codes))
# fix right labels if there were any nulls
for i in range(len(join_keys)):
mask = index.codes[i] == -1
if mask.any():
# check if there already was any nulls at this location
# if there was, it is factorized to `shape[i] - 1`
a = join_keys[i][lcodes[i] == shape[i] - 1]
if a.size == 0 or not a[0] != a[0]:
shape[i] += 1
rcodes[i][mask] = shape[i] - 1
# get flat i8 join keys
lkey, rkey = _get_join_keys(lcodes, rcodes, shape, sort)
# factorize keys to a dense i8 space
lkey, rkey, count = fkeys(lkey, rkey)
return libjoin.left_outer_join(lkey, rkey, count, sort=sort)
def _get_single_indexer(join_key, index, sort=False):
left_key, right_key, count = _factorize_keys(join_key, index, sort=sort)
left_indexer, right_indexer = libjoin.left_outer_join(
ensure_int64(left_key), ensure_int64(right_key), count, sort=sort
)
return left_indexer, right_indexer
def _left_join_on_index(left_ax, right_ax, join_keys, sort=False):
if len(join_keys) > 1:
if not (
(isinstance(right_ax, MultiIndex) and len(join_keys) == right_ax.nlevels)
):
raise AssertionError(
"If more than one join key is given then "
"'right_ax' must be a MultiIndex and the "
"number of join keys must be the number of "
"levels in right_ax"
)
left_indexer, right_indexer = _get_multiindex_indexer(
join_keys, right_ax, sort=sort
)
else:
jkey = join_keys[0]
left_indexer, right_indexer = _get_single_indexer(jkey, right_ax, sort=sort)
if sort or len(left_ax) != len(left_indexer):
# if asked to sort or there are 1-to-many matches
join_index = left_ax.take(left_indexer)
return join_index, left_indexer, right_indexer
# left frame preserves order & length of its index
return left_ax, None, right_indexer
def _right_outer_join(x, y, max_groups):
right_indexer, left_indexer = libjoin.left_outer_join(y, x, max_groups)
return left_indexer, right_indexer
_join_functions = {
"inner": libjoin.inner_join,
"left": libjoin.left_outer_join,
"right": _right_outer_join,
"outer": libjoin.full_outer_join,
}
def _factorize_keys(lk, rk, sort=True):
# Some pre-processing for non-ndarray lk / rk
if is_datetime64tz_dtype(lk) and is_datetime64tz_dtype(rk):
lk = getattr(lk, "_values", lk)._data
rk = getattr(rk, "_values", rk)._data
elif (
is_categorical_dtype(lk) and is_categorical_dtype(rk) and lk.is_dtype_equal(rk)
):
if lk.categories.equals(rk.categories):
# if we exactly match in categories, allow us to factorize on codes
rk = rk.codes
else:
# Same categories in different orders -> recode
rk = _recode_for_categories(rk.codes, rk.categories, lk.categories)
lk = ensure_int64(lk.codes)
rk = ensure_int64(rk)
elif (
is_extension_array_dtype(lk.dtype)
and is_extension_array_dtype(rk.dtype)
and lk.dtype == rk.dtype
):
lk, _ = lk._values_for_factorize()
rk, _ = rk._values_for_factorize()
if is_integer_dtype(lk) and is_integer_dtype(rk):
# GH#23917 TODO: needs tests for case where lk is integer-dtype
# and rk is datetime-dtype
klass = libhashtable.Int64Factorizer
lk = ensure_int64(com.values_from_object(lk))
rk = ensure_int64(com.values_from_object(rk))
elif issubclass(lk.dtype.type, (np.timedelta64, np.datetime64)) and issubclass(
rk.dtype.type, (np.timedelta64, np.datetime64)
):
# GH#23917 TODO: Needs tests for non-matching dtypes
klass = libhashtable.Int64Factorizer
lk = ensure_int64(com.values_from_object(lk))
rk = ensure_int64(com.values_from_object(rk))
else:
klass = libhashtable.Factorizer
lk = ensure_object(lk)
rk = ensure_object(rk)
rizer = klass(max(len(lk), len(rk)))
llab = rizer.factorize(lk)
rlab = rizer.factorize(rk)
count = rizer.get_count()
if sort:
uniques = rizer.uniques.to_array()
llab, rlab = _sort_labels(uniques, llab, rlab)
# NA group
lmask = llab == -1
lany = lmask.any()
rmask = rlab == -1
rany = rmask.any()
if lany or rany:
if lany:
np.putmask(llab, lmask, count)
if rany:
np.putmask(rlab, rmask, count)
count += 1
return llab, rlab, count
def _sort_labels(uniques, left, right):
if not isinstance(uniques, np.ndarray):
# tuplesafe
uniques = Index(uniques).values
llength = len(left)
labels = np.concatenate([left, right])
_, new_labels = sorting.safe_sort(uniques, labels, na_sentinel=-1)
new_labels = ensure_int64(new_labels)
new_left, new_right = new_labels[:llength], new_labels[llength:]
return new_left, new_right
def _get_join_keys(llab, rlab, shape, sort):
# how many levels can be done without overflow
pred = lambda i: not is_int64_overflow_possible(shape[:i])
nlev = next(filter(pred, range(len(shape), 0, -1)))
# get keys for the first `nlev` levels
stride = np.prod(shape[1:nlev], dtype="i8")
lkey = stride * llab[0].astype("i8", subok=False, copy=False)
rkey = stride * rlab[0].astype("i8", subok=False, copy=False)
for i in range(1, nlev):
with np.errstate(divide="ignore"):
stride //= shape[i]
lkey += llab[i] * stride
rkey += rlab[i] * stride
if nlev == len(shape): # all done!
return lkey, rkey
# densify current keys to avoid overflow
lkey, rkey, count = _factorize_keys(lkey, rkey, sort=sort)
llab = [lkey] + llab[nlev:]
rlab = [rkey] + rlab[nlev:]
shape = [count] + shape[nlev:]
return _get_join_keys(llab, rlab, shape, sort)
def _should_fill(lname, rname):
if not isinstance(lname, str) or not isinstance(rname, str):
return True
return lname == rname
def _any(x):
return x is not None and com.any_not_none(*x)
def validate_operand(obj):
if isinstance(obj, DataFrame):
return obj
elif isinstance(obj, Series):
if obj.name is None:
raise ValueError("Cannot merge a Series without a name")
else:
return obj.to_frame()
else:
raise TypeError(
"Can only merge Series or DataFrame objects, "
"a {obj} was passed".format(obj=type(obj))
)
def _items_overlap_with_suffix(left, lsuffix, right, rsuffix):
"""
If two indices overlap, add suffixes to overlapping entries.
If corresponding suffix is empty, the entry is simply converted to string.
"""
to_rename = left.intersection(right)
if len(to_rename) == 0:
return left, right
if not lsuffix and not rsuffix:
raise ValueError(
"columns overlap but no suffix specified: "
"{rename}".format(rename=to_rename)
)
def renamer(x, suffix):
"""
Rename the left and right indices.
If there is overlap, and suffix is not None, add
suffix, otherwise, leave it as-is.
Parameters
----------
x : original column name
suffix : str or None
Returns
-------
x : renamed column name
"""
if x in to_rename and suffix is not None:
return "{x}{suffix}".format(x=x, suffix=suffix)
return x
lrenamer = partial(renamer, suffix=lsuffix)
rrenamer = partial(renamer, suffix=rsuffix)
return (_transform_index(left, lrenamer), _transform_index(right, rrenamer))
| BugsInPy/BugsInPy/temp/projects/pandas/bug-136-fixed/pandas/pandas/core/reshape/merge.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-136-buggy/pandas/pandas/core/reshape/merge.py |
pandas-bug-82 | # TODO: Needs a better name; too many modules are already called "concat"
from collections import defaultdict
import copy
import numpy as np
from pandas._libs import internals as libinternals, tslibs
from pandas.util._decorators import cache_readonly
from pandas.core.dtypes.cast import maybe_promote
from pandas.core.dtypes.common import (
_get_dtype,
is_categorical_dtype,
is_datetime64_dtype,
is_datetime64tz_dtype,
is_extension_array_dtype,
is_float_dtype,
is_numeric_dtype,
is_sparse,
is_timedelta64_dtype,
)
from pandas.core.dtypes.concat import concat_compat
from pandas.core.dtypes.missing import isna
import pandas.core.algorithms as algos
def get_mgr_concatenation_plan(mgr, indexers):
"""
Construct concatenation plan for given block manager and indexers.
Parameters
----------
mgr : BlockManager
indexers : dict of {axis: indexer}
Returns
-------
plan : list of (BlockPlacement, JoinUnit) tuples
"""
# Calculate post-reindex shape , save for item axis which will be separate
# for each block anyway.
mgr_shape = list(mgr.shape)
for ax, indexer in indexers.items():
mgr_shape[ax] = len(indexer)
mgr_shape = tuple(mgr_shape)
if 0 in indexers:
ax0_indexer = indexers.pop(0)
blknos = algos.take_1d(mgr._blknos, ax0_indexer, fill_value=-1)
blklocs = algos.take_1d(mgr._blklocs, ax0_indexer, fill_value=-1)
else:
if mgr._is_single_block:
blk = mgr.blocks[0]
return [(blk.mgr_locs, JoinUnit(blk, mgr_shape, indexers))]
ax0_indexer = None
blknos = mgr._blknos
blklocs = mgr._blklocs
plan = []
for blkno, placements in libinternals.get_blkno_placements(blknos, group=False):
assert placements.is_slice_like
join_unit_indexers = indexers.copy()
shape = list(mgr_shape)
shape[0] = len(placements)
shape = tuple(shape)
if blkno == -1:
unit = JoinUnit(None, shape)
else:
blk = mgr.blocks[blkno]
ax0_blk_indexer = blklocs[placements.indexer]
unit_no_ax0_reindexing = (
len(placements) == len(blk.mgr_locs)
and
# Fastpath detection of join unit not
# needing to reindex its block: no ax0
# reindexing took place and block
# placement was sequential before.
(
(
ax0_indexer is None
and blk.mgr_locs.is_slice_like
and blk.mgr_locs.as_slice.step == 1
)
or
# Slow-ish detection: all indexer locs
# are sequential (and length match is
# checked above).
(np.diff(ax0_blk_indexer) == 1).all()
)
)
# Omit indexer if no item reindexing is required.
if unit_no_ax0_reindexing:
join_unit_indexers.pop(0, None)
else:
join_unit_indexers[0] = ax0_blk_indexer
unit = JoinUnit(blk, shape, join_unit_indexers)
plan.append((placements, unit))
return plan
class JoinUnit:
def __init__(self, block, shape, indexers=None):
# Passing shape explicitly is required for cases when block is None.
if indexers is None:
indexers = {}
self.block = block
self.indexers = indexers
self.shape = shape
def __repr__(self) -> str:
return f"{type(self).__name__}({repr(self.block)}, {self.indexers})"
@cache_readonly
def needs_filling(self):
for indexer in self.indexers.values():
# FIXME: cache results of indexer == -1 checks.
if (indexer == -1).any():
return True
return False
@cache_readonly
def dtype(self):
if self.block is None:
raise AssertionError("Block is None, no dtype")
if not self.needs_filling:
return self.block.dtype
else:
return _get_dtype(maybe_promote(self.block.dtype, self.block.fill_value)[0])
@cache_readonly
def is_na(self):
if self.block is None:
return True
if not self.block._can_hold_na:
return False
# Usually it's enough to check but a small fraction of values to see if
# a block is NOT null, chunks should help in such cases. 1000 value
# was chosen rather arbitrarily.
values = self.block.values
if self.block.is_categorical:
values_flat = values.categories
elif is_sparse(self.block.values.dtype):
return False
elif self.block.is_extension:
values_flat = values
else:
values_flat = values.ravel(order="K")
total_len = values_flat.shape[0]
chunk_len = max(total_len // 40, 1000)
for i in range(0, total_len, chunk_len):
if not isna(values_flat[i : i + chunk_len]).all():
return False
return True
def get_reindexed_values(self, empty_dtype, upcasted_na):
if upcasted_na is None:
# No upcasting is necessary
fill_value = self.block.fill_value
values = self.block.get_values()
else:
fill_value = upcasted_na
if self.is_na:
if getattr(self.block, "is_object", False):
# we want to avoid filling with np.nan if we are
# using None; we already know that we are all
# nulls
values = self.block.values.ravel(order="K")
if len(values) and values[0] is None:
fill_value = None
if getattr(self.block, "is_datetimetz", False) or is_datetime64tz_dtype(
empty_dtype
):
if self.block is None:
array = empty_dtype.construct_array_type()
return array(
np.full(self.shape[1], fill_value.value), dtype=empty_dtype
)
elif getattr(self.block, "is_categorical", False):
pass
elif getattr(self.block, "is_extension", False):
pass
else:
missing_arr = np.empty(self.shape, dtype=empty_dtype)
missing_arr.fill(fill_value)
return missing_arr
if not self.indexers:
if not self.block._can_consolidate:
# preserve these for validation in concat_compat
return self.block.values
if self.block.is_bool and not self.block.is_categorical:
# External code requested filling/upcasting, bool values must
# be upcasted to object to avoid being upcasted to numeric.
values = self.block.astype(np.object_).values
elif self.block.is_extension:
values = self.block.values
else:
# No dtype upcasting is done here, it will be performed during
# concatenation itself.
values = self.block.get_values()
if not self.indexers:
# If there's no indexing to be done, we want to signal outside
# code that this array must be copied explicitly. This is done
# by returning a view and checking `retval.base`.
values = values.view()
else:
for ax, indexer in self.indexers.items():
values = algos.take_nd(values, indexer, axis=ax, fill_value=fill_value)
return values
def concatenate_join_units(join_units, concat_axis, copy):
"""
Concatenate values from several join units along selected axis.
"""
if concat_axis == 0 and len(join_units) > 1:
# Concatenating join units along ax0 is handled in _merge_blocks.
raise AssertionError("Concatenating join units along axis0")
empty_dtype, upcasted_na = _get_empty_dtype_and_na(join_units)
to_concat = [
ju.get_reindexed_values(empty_dtype=empty_dtype, upcasted_na=upcasted_na)
for ju in join_units
]
if len(to_concat) == 1:
# Only one block, nothing to concatenate.
concat_values = to_concat[0]
if copy:
if isinstance(concat_values, np.ndarray):
# non-reindexed (=not yet copied) arrays are made into a view
# in JoinUnit.get_reindexed_values
if concat_values.base is not None:
concat_values = concat_values.copy()
else:
concat_values = concat_values.copy()
else:
concat_values = concat_compat(to_concat, axis=concat_axis)
return concat_values
def _get_empty_dtype_and_na(join_units):
"""
Return dtype and N/A values to use when concatenating specified units.
Returned N/A value may be None which means there was no casting involved.
Returns
-------
dtype
na
"""
if len(join_units) == 1:
blk = join_units[0].block
if blk is None:
return np.float64, np.nan
if _is_uniform_reindex(join_units):
# FIXME: integrate property
empty_dtype = join_units[0].block.dtype
upcasted_na = join_units[0].block.fill_value
return empty_dtype, upcasted_na
has_none_blocks = False
dtypes = [None] * len(join_units)
for i, unit in enumerate(join_units):
if unit.block is None:
has_none_blocks = True
else:
dtypes[i] = unit.dtype
upcast_classes = defaultdict(list)
null_upcast_classes = defaultdict(list)
for dtype, unit in zip(dtypes, join_units):
if dtype is None:
continue
if is_categorical_dtype(dtype):
upcast_cls = "category"
elif is_datetime64tz_dtype(dtype):
upcast_cls = "datetimetz"
elif issubclass(dtype.type, np.bool_):
upcast_cls = "bool"
elif issubclass(dtype.type, np.object_):
upcast_cls = "object"
elif is_datetime64_dtype(dtype):
upcast_cls = "datetime"
elif is_timedelta64_dtype(dtype):
upcast_cls = "timedelta"
elif is_sparse(dtype):
upcast_cls = dtype.subtype.name
elif is_extension_array_dtype(dtype):
upcast_cls = "object"
elif is_float_dtype(dtype) or is_numeric_dtype(dtype):
upcast_cls = dtype.name
else:
upcast_cls = "float"
# Null blocks should not influence upcast class selection, unless there
# are only null blocks, when same upcasting rules must be applied to
# null upcast classes.
if unit.is_na:
null_upcast_classes[upcast_cls].append(dtype)
else:
upcast_classes[upcast_cls].append(dtype)
if not upcast_classes:
upcast_classes = null_upcast_classes
# TODO: de-duplicate with maybe_promote?
# create the result
if "object" in upcast_classes:
return np.dtype(np.object_), np.nan
elif "bool" in upcast_classes:
if has_none_blocks:
return np.dtype(np.object_), np.nan
else:
return np.dtype(np.bool_), None
elif "category" in upcast_classes:
return np.dtype(np.object_), np.nan
elif "datetimetz" in upcast_classes:
# GH-25014. We use NaT instead of iNaT, since this eventually
# ends up in DatetimeArray.take, which does not allow iNaT.
dtype = upcast_classes["datetimetz"]
return dtype[0], tslibs.NaT
elif "datetime" in upcast_classes:
return np.dtype("M8[ns]"), tslibs.iNaT
elif "timedelta" in upcast_classes:
return np.dtype("m8[ns]"), np.timedelta64("NaT", "ns")
else: # pragma
try:
g = np.find_common_type(upcast_classes, [])
except TypeError:
# At least one is an ExtensionArray
return np.dtype(np.object_), np.nan
else:
if is_float_dtype(g):
return g, g.type(np.nan)
elif is_numeric_dtype(g):
if has_none_blocks:
return np.float64, np.nan
else:
return g, None
msg = "invalid dtype determination in get_concat_dtype"
raise AssertionError(msg)
def is_uniform_join_units(join_units):
"""
Check if the join units consist of blocks of uniform type that can
be concatenated using Block.concat_same_type instead of the generic
concatenate_join_units (which uses `concat_compat`).
"""
return (
# all blocks need to have the same type
all(type(ju.block) is type(join_units[0].block) for ju in join_units)
and # noqa
# no blocks that would get missing values (can lead to type upcasts)
# unless we're an extension dtype.
all(not ju.is_na or ju.block.is_extension for ju in join_units)
and
# no blocks with indexers (as then the dimensions do not fit)
all(not ju.indexers for ju in join_units)
and
# only use this path when there is something to concatenate
len(join_units) > 1
)
def _is_uniform_reindex(join_units) -> bool:
return (
# TODO: should this be ju.block._can_hold_na?
all(ju.block and ju.block.is_extension for ju in join_units)
and len({ju.block.dtype.name for ju in join_units}) == 1
)
def _trim_join_unit(join_unit, length):
"""
Reduce join_unit's shape along item axis to length.
Extra items that didn't fit are returned as a separate block.
"""
if 0 not in join_unit.indexers:
extra_indexers = join_unit.indexers
if join_unit.block is None:
extra_block = None
else:
extra_block = join_unit.block.getitem_block(slice(length, None))
join_unit.block = join_unit.block.getitem_block(slice(length))
else:
extra_block = join_unit.block
extra_indexers = copy.copy(join_unit.indexers)
extra_indexers[0] = extra_indexers[0][length:]
join_unit.indexers[0] = join_unit.indexers[0][:length]
extra_shape = (join_unit.shape[0] - length,) + join_unit.shape[1:]
join_unit.shape = (length,) + join_unit.shape[1:]
return JoinUnit(block=extra_block, indexers=extra_indexers, shape=extra_shape)
def combine_concat_plans(plans, concat_axis):
"""
Combine multiple concatenation plans into one.
existing_plan is updated in-place.
"""
if len(plans) == 1:
for p in plans[0]:
yield p[0], [p[1]]
elif concat_axis == 0:
offset = 0
for plan in plans:
last_plc = None
for plc, unit in plan:
yield plc.add(offset), [unit]
last_plc = plc
if last_plc is not None:
offset += last_plc.as_slice.stop
else:
num_ended = [0]
def _next_or_none(seq):
retval = next(seq, None)
if retval is None:
num_ended[0] += 1
return retval
plans = list(map(iter, plans))
next_items = list(map(_next_or_none, plans))
while num_ended[0] != len(next_items):
if num_ended[0] > 0:
raise ValueError("Plan shapes are not aligned")
placements, units = zip(*next_items)
lengths = list(map(len, placements))
min_len, max_len = min(lengths), max(lengths)
if min_len == max_len:
yield placements[0], units
next_items[:] = map(_next_or_none, plans)
else:
yielded_placement = None
yielded_units = [None] * len(next_items)
for i, (plc, unit) in enumerate(next_items):
yielded_units[i] = unit
if len(plc) > min_len:
# _trim_join_unit updates unit in place, so only
# placement needs to be sliced to skip min_len.
next_items[i] = (plc[min_len:], _trim_join_unit(unit, min_len))
else:
yielded_placement = plc
next_items[i] = _next_or_none(plans[i])
yield yielded_placement, yielded_units
# TODO: Needs a better name; too many modules are already called "concat"
from collections import defaultdict
import copy
import numpy as np
from pandas._libs import internals as libinternals, tslibs
from pandas.util._decorators import cache_readonly
from pandas.core.dtypes.cast import maybe_promote
from pandas.core.dtypes.common import (
_get_dtype,
is_categorical_dtype,
is_datetime64_dtype,
is_datetime64tz_dtype,
is_extension_array_dtype,
is_float_dtype,
is_numeric_dtype,
is_sparse,
is_timedelta64_dtype,
)
from pandas.core.dtypes.concat import concat_compat
from pandas.core.dtypes.missing import isna
import pandas.core.algorithms as algos
def get_mgr_concatenation_plan(mgr, indexers):
"""
Construct concatenation plan for given block manager and indexers.
Parameters
----------
mgr : BlockManager
indexers : dict of {axis: indexer}
Returns
-------
plan : list of (BlockPlacement, JoinUnit) tuples
"""
# Calculate post-reindex shape , save for item axis which will be separate
# for each block anyway.
mgr_shape = list(mgr.shape)
for ax, indexer in indexers.items():
mgr_shape[ax] = len(indexer)
mgr_shape = tuple(mgr_shape)
if 0 in indexers:
ax0_indexer = indexers.pop(0)
blknos = algos.take_1d(mgr._blknos, ax0_indexer, fill_value=-1)
blklocs = algos.take_1d(mgr._blklocs, ax0_indexer, fill_value=-1)
else:
if mgr._is_single_block:
blk = mgr.blocks[0]
return [(blk.mgr_locs, JoinUnit(blk, mgr_shape, indexers))]
ax0_indexer = None
blknos = mgr._blknos
blklocs = mgr._blklocs
plan = []
for blkno, placements in libinternals.get_blkno_placements(blknos, group=False):
assert placements.is_slice_like
join_unit_indexers = indexers.copy()
shape = list(mgr_shape)
shape[0] = len(placements)
shape = tuple(shape)
if blkno == -1:
unit = JoinUnit(None, shape)
else:
blk = mgr.blocks[blkno]
ax0_blk_indexer = blklocs[placements.indexer]
unit_no_ax0_reindexing = (
len(placements) == len(blk.mgr_locs)
and
# Fastpath detection of join unit not
# needing to reindex its block: no ax0
# reindexing took place and block
# placement was sequential before.
(
(
ax0_indexer is None
and blk.mgr_locs.is_slice_like
and blk.mgr_locs.as_slice.step == 1
)
or
# Slow-ish detection: all indexer locs
# are sequential (and length match is
# checked above).
(np.diff(ax0_blk_indexer) == 1).all()
)
)
# Omit indexer if no item reindexing is required.
if unit_no_ax0_reindexing:
join_unit_indexers.pop(0, None)
else:
join_unit_indexers[0] = ax0_blk_indexer
unit = JoinUnit(blk, shape, join_unit_indexers)
plan.append((placements, unit))
return plan
class JoinUnit:
def __init__(self, block, shape, indexers=None):
# Passing shape explicitly is required for cases when block is None.
if indexers is None:
indexers = {}
self.block = block
self.indexers = indexers
self.shape = shape
def __repr__(self) -> str:
return f"{type(self).__name__}({repr(self.block)}, {self.indexers})"
@cache_readonly
def needs_filling(self):
for indexer in self.indexers.values():
# FIXME: cache results of indexer == -1 checks.
if (indexer == -1).any():
return True
return False
@cache_readonly
def dtype(self):
if self.block is None:
raise AssertionError("Block is None, no dtype")
if not self.needs_filling:
return self.block.dtype
else:
return _get_dtype(maybe_promote(self.block.dtype, self.block.fill_value)[0])
@cache_readonly
def is_na(self):
if self.block is None:
return True
if not self.block._can_hold_na:
return False
# Usually it's enough to check but a small fraction of values to see if
# a block is NOT null, chunks should help in such cases. 1000 value
# was chosen rather arbitrarily.
values = self.block.values
if self.block.is_categorical:
values_flat = values.categories
elif is_sparse(self.block.values.dtype):
return False
elif self.block.is_extension:
values_flat = values
else:
values_flat = values.ravel(order="K")
total_len = values_flat.shape[0]
chunk_len = max(total_len // 40, 1000)
for i in range(0, total_len, chunk_len):
if not isna(values_flat[i : i + chunk_len]).all():
return False
return True
def get_reindexed_values(self, empty_dtype, upcasted_na):
if upcasted_na is None:
# No upcasting is necessary
fill_value = self.block.fill_value
values = self.block.get_values()
else:
fill_value = upcasted_na
if self.is_na:
if getattr(self.block, "is_object", False):
# we want to avoid filling with np.nan if we are
# using None; we already know that we are all
# nulls
values = self.block.values.ravel(order="K")
if len(values) and values[0] is None:
fill_value = None
if getattr(self.block, "is_datetimetz", False) or is_datetime64tz_dtype(
empty_dtype
):
if self.block is None:
array = empty_dtype.construct_array_type()
return array(
np.full(self.shape[1], fill_value.value), dtype=empty_dtype
)
elif getattr(self.block, "is_categorical", False):
pass
elif getattr(self.block, "is_extension", False):
pass
else:
missing_arr = np.empty(self.shape, dtype=empty_dtype)
missing_arr.fill(fill_value)
return missing_arr
if not self.indexers:
if not self.block._can_consolidate:
# preserve these for validation in concat_compat
return self.block.values
if self.block.is_bool and not self.block.is_categorical:
# External code requested filling/upcasting, bool values must
# be upcasted to object to avoid being upcasted to numeric.
values = self.block.astype(np.object_).values
elif self.block.is_extension:
values = self.block.values
else:
# No dtype upcasting is done here, it will be performed during
# concatenation itself.
values = self.block.get_values()
if not self.indexers:
# If there's no indexing to be done, we want to signal outside
# code that this array must be copied explicitly. This is done
# by returning a view and checking `retval.base`.
values = values.view()
else:
for ax, indexer in self.indexers.items():
values = algos.take_nd(values, indexer, axis=ax, fill_value=fill_value)
return values
def concatenate_join_units(join_units, concat_axis, copy):
"""
Concatenate values from several join units along selected axis.
"""
if concat_axis == 0 and len(join_units) > 1:
# Concatenating join units along ax0 is handled in _merge_blocks.
raise AssertionError("Concatenating join units along axis0")
empty_dtype, upcasted_na = _get_empty_dtype_and_na(join_units)
to_concat = [
ju.get_reindexed_values(empty_dtype=empty_dtype, upcasted_na=upcasted_na)
for ju in join_units
]
if len(to_concat) == 1:
# Only one block, nothing to concatenate.
concat_values = to_concat[0]
if copy:
if isinstance(concat_values, np.ndarray):
# non-reindexed (=not yet copied) arrays are made into a view
# in JoinUnit.get_reindexed_values
if concat_values.base is not None:
concat_values = concat_values.copy()
else:
concat_values = concat_values.copy()
else:
concat_values = concat_compat(to_concat, axis=concat_axis)
return concat_values
def _get_empty_dtype_and_na(join_units):
"""
Return dtype and N/A values to use when concatenating specified units.
Returned N/A value may be None which means there was no casting involved.
Returns
-------
dtype
na
"""
if len(join_units) == 1:
blk = join_units[0].block
if blk is None:
return np.float64, np.nan
if _is_uniform_reindex(join_units):
# FIXME: integrate property
empty_dtype = join_units[0].block.dtype
upcasted_na = join_units[0].block.fill_value
return empty_dtype, upcasted_na
has_none_blocks = False
dtypes = [None] * len(join_units)
for i, unit in enumerate(join_units):
if unit.block is None:
has_none_blocks = True
else:
dtypes[i] = unit.dtype
upcast_classes = defaultdict(list)
null_upcast_classes = defaultdict(list)
for dtype, unit in zip(dtypes, join_units):
if dtype is None:
continue
if is_categorical_dtype(dtype):
upcast_cls = "category"
elif is_datetime64tz_dtype(dtype):
upcast_cls = "datetimetz"
elif issubclass(dtype.type, np.bool_):
upcast_cls = "bool"
elif issubclass(dtype.type, np.object_):
upcast_cls = "object"
elif is_datetime64_dtype(dtype):
upcast_cls = "datetime"
elif is_timedelta64_dtype(dtype):
upcast_cls = "timedelta"
elif is_sparse(dtype):
upcast_cls = dtype.subtype.name
elif is_extension_array_dtype(dtype):
upcast_cls = "object"
elif is_float_dtype(dtype) or is_numeric_dtype(dtype):
upcast_cls = dtype.name
else:
upcast_cls = "float"
# Null blocks should not influence upcast class selection, unless there
# are only null blocks, when same upcasting rules must be applied to
# null upcast classes.
if unit.is_na:
null_upcast_classes[upcast_cls].append(dtype)
else:
upcast_classes[upcast_cls].append(dtype)
if not upcast_classes:
upcast_classes = null_upcast_classes
# TODO: de-duplicate with maybe_promote?
# create the result
if "object" in upcast_classes:
return np.dtype(np.object_), np.nan
elif "bool" in upcast_classes:
if has_none_blocks:
return np.dtype(np.object_), np.nan
else:
return np.dtype(np.bool_), None
elif "category" in upcast_classes:
return np.dtype(np.object_), np.nan
elif "datetimetz" in upcast_classes:
# GH-25014. We use NaT instead of iNaT, since this eventually
# ends up in DatetimeArray.take, which does not allow iNaT.
dtype = upcast_classes["datetimetz"]
return dtype[0], tslibs.NaT
elif "datetime" in upcast_classes:
return np.dtype("M8[ns]"), np.datetime64("NaT", "ns")
elif "timedelta" in upcast_classes:
return np.dtype("m8[ns]"), np.timedelta64("NaT", "ns")
else: # pragma
try:
g = np.find_common_type(upcast_classes, [])
except TypeError:
# At least one is an ExtensionArray
return np.dtype(np.object_), np.nan
else:
if is_float_dtype(g):
return g, g.type(np.nan)
elif is_numeric_dtype(g):
if has_none_blocks:
return np.float64, np.nan
else:
return g, None
msg = "invalid dtype determination in get_concat_dtype"
raise AssertionError(msg)
def is_uniform_join_units(join_units):
"""
Check if the join units consist of blocks of uniform type that can
be concatenated using Block.concat_same_type instead of the generic
concatenate_join_units (which uses `concat_compat`).
"""
return (
# all blocks need to have the same type
all(type(ju.block) is type(join_units[0].block) for ju in join_units)
and # noqa
# no blocks that would get missing values (can lead to type upcasts)
# unless we're an extension dtype.
all(not ju.is_na or ju.block.is_extension for ju in join_units)
and
# no blocks with indexers (as then the dimensions do not fit)
all(not ju.indexers for ju in join_units)
and
# only use this path when there is something to concatenate
len(join_units) > 1
)
def _is_uniform_reindex(join_units) -> bool:
return (
# TODO: should this be ju.block._can_hold_na?
all(ju.block and ju.block.is_extension for ju in join_units)
and len({ju.block.dtype.name for ju in join_units}) == 1
)
def _trim_join_unit(join_unit, length):
"""
Reduce join_unit's shape along item axis to length.
Extra items that didn't fit are returned as a separate block.
"""
if 0 not in join_unit.indexers:
extra_indexers = join_unit.indexers
if join_unit.block is None:
extra_block = None
else:
extra_block = join_unit.block.getitem_block(slice(length, None))
join_unit.block = join_unit.block.getitem_block(slice(length))
else:
extra_block = join_unit.block
extra_indexers = copy.copy(join_unit.indexers)
extra_indexers[0] = extra_indexers[0][length:]
join_unit.indexers[0] = join_unit.indexers[0][:length]
extra_shape = (join_unit.shape[0] - length,) + join_unit.shape[1:]
join_unit.shape = (length,) + join_unit.shape[1:]
return JoinUnit(block=extra_block, indexers=extra_indexers, shape=extra_shape)
def combine_concat_plans(plans, concat_axis):
"""
Combine multiple concatenation plans into one.
existing_plan is updated in-place.
"""
if len(plans) == 1:
for p in plans[0]:
yield p[0], [p[1]]
elif concat_axis == 0:
offset = 0
for plan in plans:
last_plc = None
for plc, unit in plan:
yield plc.add(offset), [unit]
last_plc = plc
if last_plc is not None:
offset += last_plc.as_slice.stop
else:
num_ended = [0]
def _next_or_none(seq):
retval = next(seq, None)
if retval is None:
num_ended[0] += 1
return retval
plans = list(map(iter, plans))
next_items = list(map(_next_or_none, plans))
while num_ended[0] != len(next_items):
if num_ended[0] > 0:
raise ValueError("Plan shapes are not aligned")
placements, units = zip(*next_items)
lengths = list(map(len, placements))
min_len, max_len = min(lengths), max(lengths)
if min_len == max_len:
yield placements[0], units
next_items[:] = map(_next_or_none, plans)
else:
yielded_placement = None
yielded_units = [None] * len(next_items)
for i, (plc, unit) in enumerate(next_items):
yielded_units[i] = unit
if len(plc) > min_len:
# _trim_join_unit updates unit in place, so only
# placement needs to be sliced to skip min_len.
next_items[i] = (plc[min_len:], _trim_join_unit(unit, min_len))
else:
yielded_placement = plc
next_items[i] = _next_or_none(plans[i])
yield yielded_placement, yielded_units
| BugsInPy/BugsInPy/temp/projects/pandas/bug-82-fixed/pandas/pandas/core/internals/concat.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-82-buggy/pandas/pandas/core/internals/concat.py |
pandas-bug-19 | from typing import TYPE_CHECKING, Hashable, List, Tuple, Union
import numpy as np
from pandas._libs.indexing import _NDFrameIndexerBase
from pandas._libs.lib import item_from_zerodim
from pandas.errors import AbstractMethodError
from pandas.util._decorators import doc
from pandas.core.dtypes.common import (
is_hashable,
is_integer,
is_iterator,
is_list_like,
is_numeric_dtype,
is_object_dtype,
is_scalar,
is_sequence,
)
from pandas.core.dtypes.concat import concat_compat
from pandas.core.dtypes.generic import ABCDataFrame, ABCMultiIndex, ABCSeries
from pandas.core.dtypes.missing import _infer_fill_value, isna
import pandas.core.common as com
from pandas.core.indexers import (
check_array_indexer,
is_list_like_indexer,
length_of_indexer,
)
from pandas.core.indexes.api import Index, InvalidIndexError
if TYPE_CHECKING:
from pandas import DataFrame # noqa:F401
# "null slice"
_NS = slice(None, None)
# the public IndexSlicerMaker
class _IndexSlice:
"""
Create an object to more easily perform multi-index slicing.
See Also
--------
MultiIndex.remove_unused_levels : New MultiIndex with no unused levels.
Notes
-----
See :ref:`Defined Levels <advanced.shown_levels>`
for further info on slicing a MultiIndex.
Examples
--------
>>> midx = pd.MultiIndex.from_product([['A0','A1'], ['B0','B1','B2','B3']])
>>> columns = ['foo', 'bar']
>>> dfmi = pd.DataFrame(np.arange(16).reshape((len(midx), len(columns))),
index=midx, columns=columns)
Using the default slice command:
>>> dfmi.loc[(slice(None), slice('B0', 'B1')), :]
foo bar
A0 B0 0 1
B1 2 3
A1 B0 8 9
B1 10 11
Using the IndexSlice class for a more intuitive command:
>>> idx = pd.IndexSlice
>>> dfmi.loc[idx[:, 'B0':'B1'], :]
foo bar
A0 B0 0 1
B1 2 3
A1 B0 8 9
B1 10 11
"""
def __getitem__(self, arg):
return arg
IndexSlice = _IndexSlice()
class IndexingError(Exception):
pass
class IndexingMixin:
"""
Mixin for adding .loc/.iloc/.at/.iat to Datafames and Series.
"""
@property
def iloc(self) -> "_iLocIndexer":
"""
Purely integer-location based indexing for selection by position.
``.iloc[]`` is primarily integer position based (from ``0`` to
``length-1`` of the axis), but may also be used with a boolean
array.
Allowed inputs are:
- An integer, e.g. ``5``.
- A list or array of integers, e.g. ``[4, 3, 0]``.
- A slice object with ints, e.g. ``1:7``.
- A boolean array.
- A ``callable`` function with one argument (the calling Series or
DataFrame) and that returns valid output for indexing (one of the above).
This is useful in method chains, when you don't have a reference to the
calling object, but would like to base your selection on some value.
``.iloc`` will raise ``IndexError`` if a requested indexer is
out-of-bounds, except *slice* indexers which allow out-of-bounds
indexing (this conforms with python/numpy *slice* semantics).
See more at :ref:`Selection by Position <indexing.integer>`.
See Also
--------
DataFrame.iat : Fast integer location scalar accessor.
DataFrame.loc : Purely label-location based indexer for selection by label.
Series.iloc : Purely integer-location based indexing for
selection by position.
Examples
--------
>>> mydict = [{'a': 1, 'b': 2, 'c': 3, 'd': 4},
... {'a': 100, 'b': 200, 'c': 300, 'd': 400},
... {'a': 1000, 'b': 2000, 'c': 3000, 'd': 4000 }]
>>> df = pd.DataFrame(mydict)
>>> df
a b c d
0 1 2 3 4
1 100 200 300 400
2 1000 2000 3000 4000
**Indexing just the rows**
With a scalar integer.
>>> type(df.iloc[0])
<class 'pandas.core.series.Series'>
>>> df.iloc[0]
a 1
b 2
c 3
d 4
Name: 0, dtype: int64
With a list of integers.
>>> df.iloc[[0]]
a b c d
0 1 2 3 4
>>> type(df.iloc[[0]])
<class 'pandas.core.frame.DataFrame'>
>>> df.iloc[[0, 1]]
a b c d
0 1 2 3 4
1 100 200 300 400
With a `slice` object.
>>> df.iloc[:3]
a b c d
0 1 2 3 4
1 100 200 300 400
2 1000 2000 3000 4000
With a boolean mask the same length as the index.
>>> df.iloc[[True, False, True]]
a b c d
0 1 2 3 4
2 1000 2000 3000 4000
With a callable, useful in method chains. The `x` passed
to the ``lambda`` is the DataFrame being sliced. This selects
the rows whose index label even.
>>> df.iloc[lambda x: x.index % 2 == 0]
a b c d
0 1 2 3 4
2 1000 2000 3000 4000
**Indexing both axes**
You can mix the indexer types for the index and columns. Use ``:`` to
select the entire axis.
With scalar integers.
>>> df.iloc[0, 1]
2
With lists of integers.
>>> df.iloc[[0, 2], [1, 3]]
b d
0 2 4
2 2000 4000
With `slice` objects.
>>> df.iloc[1:3, 0:3]
a b c
1 100 200 300
2 1000 2000 3000
With a boolean array whose length matches the columns.
>>> df.iloc[:, [True, False, True, False]]
a c
0 1 3
1 100 300
2 1000 3000
With a callable function that expects the Series or DataFrame.
>>> df.iloc[:, lambda df: [0, 2]]
a c
0 1 3
1 100 300
2 1000 3000
"""
return _iLocIndexer("iloc", self)
@property
def loc(self) -> "_LocIndexer":
"""
Access a group of rows and columns by label(s) or a boolean array.
``.loc[]`` is primarily label based, but may also be used with a
boolean array.
Allowed inputs are:
- A single label, e.g. ``5`` or ``'a'``, (note that ``5`` is
interpreted as a *label* of the index, and **never** as an
integer position along the index).
- A list or array of labels, e.g. ``['a', 'b', 'c']``.
- A slice object with labels, e.g. ``'a':'f'``.
.. warning:: Note that contrary to usual python slices, **both** the
start and the stop are included
- A boolean array of the same length as the axis being sliced,
e.g. ``[True, False, True]``.
- A ``callable`` function with one argument (the calling Series or
DataFrame) and that returns valid output for indexing (one of the above)
See more at :ref:`Selection by Label <indexing.label>`
Raises
------
KeyError
If any items are not found.
See Also
--------
DataFrame.at : Access a single value for a row/column label pair.
DataFrame.iloc : Access group of rows and columns by integer position(s).
DataFrame.xs : Returns a cross-section (row(s) or column(s)) from the
Series/DataFrame.
Series.loc : Access group of values using labels.
Examples
--------
**Getting values**
>>> df = pd.DataFrame([[1, 2], [4, 5], [7, 8]],
... index=['cobra', 'viper', 'sidewinder'],
... columns=['max_speed', 'shield'])
>>> df
max_speed shield
cobra 1 2
viper 4 5
sidewinder 7 8
Single label. Note this returns the row as a Series.
>>> df.loc['viper']
max_speed 4
shield 5
Name: viper, dtype: int64
List of labels. Note using ``[[]]`` returns a DataFrame.
>>> df.loc[['viper', 'sidewinder']]
max_speed shield
viper 4 5
sidewinder 7 8
Single label for row and column
>>> df.loc['cobra', 'shield']
2
Slice with labels for row and single label for column. As mentioned
above, note that both the start and stop of the slice are included.
>>> df.loc['cobra':'viper', 'max_speed']
cobra 1
viper 4
Name: max_speed, dtype: int64
Boolean list with the same length as the row axis
>>> df.loc[[False, False, True]]
max_speed shield
sidewinder 7 8
Conditional that returns a boolean Series
>>> df.loc[df['shield'] > 6]
max_speed shield
sidewinder 7 8
Conditional that returns a boolean Series with column labels specified
>>> df.loc[df['shield'] > 6, ['max_speed']]
max_speed
sidewinder 7
Callable that returns a boolean Series
>>> df.loc[lambda df: df['shield'] == 8]
max_speed shield
sidewinder 7 8
**Setting values**
Set value for all items matching the list of labels
>>> df.loc[['viper', 'sidewinder'], ['shield']] = 50
>>> df
max_speed shield
cobra 1 2
viper 4 50
sidewinder 7 50
Set value for an entire row
>>> df.loc['cobra'] = 10
>>> df
max_speed shield
cobra 10 10
viper 4 50
sidewinder 7 50
Set value for an entire column
>>> df.loc[:, 'max_speed'] = 30
>>> df
max_speed shield
cobra 30 10
viper 30 50
sidewinder 30 50
Set value for rows matching callable condition
>>> df.loc[df['shield'] > 35] = 0
>>> df
max_speed shield
cobra 30 10
viper 0 0
sidewinder 0 0
**Getting values on a DataFrame with an index that has integer labels**
Another example using integers for the index
>>> df = pd.DataFrame([[1, 2], [4, 5], [7, 8]],
... index=[7, 8, 9], columns=['max_speed', 'shield'])
>>> df
max_speed shield
7 1 2
8 4 5
9 7 8
Slice with integer labels for rows. As mentioned above, note that both
the start and stop of the slice are included.
>>> df.loc[7:9]
max_speed shield
7 1 2
8 4 5
9 7 8
**Getting values with a MultiIndex**
A number of examples using a DataFrame with a MultiIndex
>>> tuples = [
... ('cobra', 'mark i'), ('cobra', 'mark ii'),
... ('sidewinder', 'mark i'), ('sidewinder', 'mark ii'),
... ('viper', 'mark ii'), ('viper', 'mark iii')
... ]
>>> index = pd.MultiIndex.from_tuples(tuples)
>>> values = [[12, 2], [0, 4], [10, 20],
... [1, 4], [7, 1], [16, 36]]
>>> df = pd.DataFrame(values, columns=['max_speed', 'shield'], index=index)
>>> df
max_speed shield
cobra mark i 12 2
mark ii 0 4
sidewinder mark i 10 20
mark ii 1 4
viper mark ii 7 1
mark iii 16 36
Single label. Note this returns a DataFrame with a single index.
>>> df.loc['cobra']
max_speed shield
mark i 12 2
mark ii 0 4
Single index tuple. Note this returns a Series.
>>> df.loc[('cobra', 'mark ii')]
max_speed 0
shield 4
Name: (cobra, mark ii), dtype: int64
Single label for row and column. Similar to passing in a tuple, this
returns a Series.
>>> df.loc['cobra', 'mark i']
max_speed 12
shield 2
Name: (cobra, mark i), dtype: int64
Single tuple. Note using ``[[]]`` returns a DataFrame.
>>> df.loc[[('cobra', 'mark ii')]]
max_speed shield
cobra mark ii 0 4
Single tuple for the index with a single label for the column
>>> df.loc[('cobra', 'mark i'), 'shield']
2
Slice from index tuple to single label
>>> df.loc[('cobra', 'mark i'):'viper']
max_speed shield
cobra mark i 12 2
mark ii 0 4
sidewinder mark i 10 20
mark ii 1 4
viper mark ii 7 1
mark iii 16 36
Slice from index tuple to index tuple
>>> df.loc[('cobra', 'mark i'):('viper', 'mark ii')]
max_speed shield
cobra mark i 12 2
mark ii 0 4
sidewinder mark i 10 20
mark ii 1 4
viper mark ii 7 1
"""
return _LocIndexer("loc", self)
@property
def at(self) -> "_AtIndexer":
"""
Access a single value for a row/column label pair.
Similar to ``loc``, in that both provide label-based lookups. Use
``at`` if you only need to get or set a single value in a DataFrame
or Series.
Raises
------
KeyError
If 'label' does not exist in DataFrame.
See Also
--------
DataFrame.iat : Access a single value for a row/column pair by integer
position.
DataFrame.loc : Access a group of rows and columns by label(s).
Series.at : Access a single value using a label.
Examples
--------
>>> df = pd.DataFrame([[0, 2, 3], [0, 4, 1], [10, 20, 30]],
... index=[4, 5, 6], columns=['A', 'B', 'C'])
>>> df
A B C
4 0 2 3
5 0 4 1
6 10 20 30
Get value at specified row/column pair
>>> df.at[4, 'B']
2
Set value at specified row/column pair
>>> df.at[4, 'B'] = 10
>>> df.at[4, 'B']
10
Get value within a Series
>>> df.loc[5].at['B']
4
"""
return _AtIndexer("at", self)
@property
def iat(self) -> "_iAtIndexer":
"""
Access a single value for a row/column pair by integer position.
Similar to ``iloc``, in that both provide integer-based lookups. Use
``iat`` if you only need to get or set a single value in a DataFrame
or Series.
Raises
------
IndexError
When integer position is out of bounds.
See Also
--------
DataFrame.at : Access a single value for a row/column label pair.
DataFrame.loc : Access a group of rows and columns by label(s).
DataFrame.iloc : Access a group of rows and columns by integer position(s).
Examples
--------
>>> df = pd.DataFrame([[0, 2, 3], [0, 4, 1], [10, 20, 30]],
... columns=['A', 'B', 'C'])
>>> df
A B C
0 0 2 3
1 0 4 1
2 10 20 30
Get value at specified row/column pair
>>> df.iat[1, 2]
1
Set value at specified row/column pair
>>> df.iat[1, 2] = 10
>>> df.iat[1, 2]
10
Get value within a series
>>> df.loc[0].iat[1]
2
"""
return _iAtIndexer("iat", self)
class _LocationIndexer(_NDFrameIndexerBase):
_valid_types: str
axis = None
def __call__(self, axis=None):
# we need to return a copy of ourselves
new_self = type(self)(self.name, self.obj)
if axis is not None:
axis = self.obj._get_axis_number(axis)
new_self.axis = axis
return new_self
def _get_setitem_indexer(self, key):
"""
Convert a potentially-label-based key into a positional indexer.
"""
if self.name == "loc":
self._ensure_listlike_indexer(key)
if self.axis is not None:
return self._convert_tuple(key, is_setter=True)
ax = self.obj._get_axis(0)
if isinstance(ax, ABCMultiIndex) and self.name != "iloc":
try:
return ax.get_loc(key)
except (TypeError, KeyError, InvalidIndexError):
# TypeError e.g. passed a bool
pass
if isinstance(key, tuple):
try:
return self._convert_tuple(key, is_setter=True)
except IndexingError:
pass
if isinstance(key, range):
return list(key)
try:
return self._convert_to_indexer(key, axis=0, is_setter=True)
except TypeError as e:
# invalid indexer type vs 'other' indexing errors
if "cannot do" in str(e):
raise
elif "unhashable type" in str(e):
raise
raise IndexingError(key) from e
def _ensure_listlike_indexer(self, key, axis=None):
"""
Ensure that a list-like of column labels are all present by adding them if
they do not already exist.
Parameters
----------
key : list-like of column labels
Target labels.
axis : key axis if known
"""
column_axis = 1
# column only exists in 2-dimensional DataFrame
if self.ndim != 2:
return
if isinstance(key, tuple):
# key may be a tuple if we are .loc
# in that case, set key to the column part of key
key = key[column_axis]
axis = column_axis
if (
axis == column_axis
and not isinstance(self.obj.columns, ABCMultiIndex)
and is_list_like_indexer(key)
and not com.is_bool_indexer(key)
and all(is_hashable(k) for k in key)
):
for k in key:
if k not in self.obj:
self.obj[k] = np.nan
def __setitem__(self, key, value):
if isinstance(key, tuple):
key = tuple(com.apply_if_callable(x, self.obj) for x in key)
else:
key = com.apply_if_callable(key, self.obj)
indexer = self._get_setitem_indexer(key)
self._has_valid_setitem_indexer(key)
iloc = self if self.name == "iloc" else self.obj.iloc
iloc._setitem_with_indexer(indexer, value)
def _validate_key(self, key, axis: int):
"""
Ensure that key is valid for current indexer.
Parameters
----------
key : scalar, slice or list-like
Key requested.
axis : int
Dimension on which the indexing is being made.
Raises
------
TypeError
If the key (or some element of it) has wrong type.
IndexError
If the key (or some element of it) is out of bounds.
KeyError
If the key was not found.
"""
raise AbstractMethodError(self)
def _has_valid_tuple(self, key: Tuple):
"""
Check the key for valid keys across my indexer.
"""
for i, k in enumerate(key):
if i >= self.ndim:
raise IndexingError("Too many indexers")
try:
self._validate_key(k, i)
except ValueError as err:
raise ValueError(
"Location based indexing can only have "
f"[{self._valid_types}] types"
) from err
def _is_nested_tuple_indexer(self, tup: Tuple) -> bool:
"""
Returns
-------
bool
"""
if any(isinstance(ax, ABCMultiIndex) for ax in self.obj.axes):
return any(is_nested_tuple(tup, ax) for ax in self.obj.axes)
return False
def _convert_tuple(self, key, is_setter: bool = False):
keyidx = []
if self.axis is not None:
axis = self.obj._get_axis_number(self.axis)
for i in range(self.ndim):
if i == axis:
keyidx.append(
self._convert_to_indexer(key, axis=axis, is_setter=is_setter)
)
else:
keyidx.append(slice(None))
else:
for i, k in enumerate(key):
if i >= self.ndim:
raise IndexingError("Too many indexers")
idx = self._convert_to_indexer(k, axis=i, is_setter=is_setter)
keyidx.append(idx)
return tuple(keyidx)
def _getitem_tuple_same_dim(self, tup: Tuple):
"""
Index with indexers that should return an object of the same dimension
as self.obj.
This is only called after a failed call to _getitem_lowerdim.
"""
retval = self.obj
for i, key in enumerate(tup):
if com.is_null_slice(key):
continue
retval = getattr(retval, self.name)._getitem_axis(key, axis=i)
# We should never have retval.ndim < self.ndim, as that should
# be handled by the _getitem_lowerdim call above.
assert retval.ndim == self.ndim
return retval
def _getitem_lowerdim(self, tup: Tuple):
# we can directly get the axis result since the axis is specified
if self.axis is not None:
axis = self.obj._get_axis_number(self.axis)
return self._getitem_axis(tup, axis=axis)
# we may have a nested tuples indexer here
if self._is_nested_tuple_indexer(tup):
return self._getitem_nested_tuple(tup)
# we maybe be using a tuple to represent multiple dimensions here
ax0 = self.obj._get_axis(0)
# ...but iloc should handle the tuple as simple integer-location
# instead of checking it as multiindex representation (GH 13797)
if isinstance(ax0, ABCMultiIndex) and self.name != "iloc":
result = self._handle_lowerdim_multi_index_axis0(tup)
if result is not None:
return result
if len(tup) > self.ndim:
raise IndexingError("Too many indexers. handle elsewhere")
for i, key in enumerate(tup):
if is_label_like(key):
# We don't need to check for tuples here because those are
# caught by the _is_nested_tuple_indexer check above.
section = self._getitem_axis(key, axis=i)
# We should never have a scalar section here, because
# _getitem_lowerdim is only called after a check for
# is_scalar_access, which that would be.
if section.ndim == self.ndim:
# we're in the middle of slicing through a MultiIndex
# revise the key wrt to `section` by inserting an _NS
new_key = tup[:i] + (_NS,) + tup[i + 1 :]
else:
# Note: the section.ndim == self.ndim check above
# rules out having DataFrame here, so we dont need to worry
# about transposing.
new_key = tup[:i] + tup[i + 1 :]
if len(new_key) == 1:
new_key = new_key[0]
# Slices should return views, but calling iloc/loc with a null
# slice returns a new object.
if com.is_null_slice(new_key):
return section
# This is an elided recursive call to iloc/loc
return getattr(section, self.name)[new_key]
raise IndexingError("not applicable")
def _getitem_nested_tuple(self, tup: Tuple):
# we have a nested tuple so have at least 1 multi-index level
# we should be able to match up the dimensionality here
# we have too many indexers for our dim, but have at least 1
# multi-index dimension, try to see if we have something like
# a tuple passed to a series with a multi-index
if len(tup) > self.ndim:
if self.name != "loc":
# This should never be reached, but lets be explicit about it
raise ValueError("Too many indices")
result = self._handle_lowerdim_multi_index_axis0(tup)
if result is not None:
return result
# this is a series with a multi-index specified a tuple of
# selectors
axis = self.axis or 0
return self._getitem_axis(tup, axis=axis)
# handle the multi-axis by taking sections and reducing
# this is iterative
obj = self.obj
axis = 0
for key in tup:
if com.is_null_slice(key):
axis += 1
continue
current_ndim = obj.ndim
obj = getattr(obj, self.name)._getitem_axis(key, axis=axis)
axis += 1
# if we have a scalar, we are done
if is_scalar(obj) or not hasattr(obj, "ndim"):
break
# has the dim of the obj changed?
# GH 7199
if obj.ndim < current_ndim:
axis -= 1
return obj
def _convert_to_indexer(self, key, axis: int, is_setter: bool = False):
raise AbstractMethodError(self)
def __getitem__(self, key):
if type(key) is tuple:
key = tuple(com.apply_if_callable(x, self.obj) for x in key)
if self._is_scalar_access(key):
try:
return self.obj._get_value(*key, takeable=self._takeable)
except (KeyError, IndexError, AttributeError):
# AttributeError for IntervalTree get_value
pass
return self._getitem_tuple(key)
else:
# we by definition only have the 0th axis
axis = self.axis or 0
maybe_callable = com.apply_if_callable(key, self.obj)
return self._getitem_axis(maybe_callable, axis=axis)
def _is_scalar_access(self, key: Tuple):
raise NotImplementedError()
def _getitem_tuple(self, tup: Tuple):
raise AbstractMethodError(self)
def _getitem_axis(self, key, axis: int):
raise NotImplementedError()
def _has_valid_setitem_indexer(self, indexer) -> bool:
raise AbstractMethodError(self)
def _getbool_axis(self, key, axis: int):
# caller is responsible for ensuring non-None axis
labels = self.obj._get_axis(axis)
key = check_bool_indexer(labels, key)
inds = key.nonzero()[0]
return self.obj._take_with_is_copy(inds, axis=axis)
@doc(IndexingMixin.loc)
class _LocIndexer(_LocationIndexer):
_takeable: bool = False
_valid_types = (
"labels (MUST BE IN THE INDEX), slices of labels (BOTH "
"endpoints included! Can be slices of integers if the "
"index is integers), listlike of labels, boolean"
)
# -------------------------------------------------------------------
# Key Checks
@doc(_LocationIndexer._validate_key)
def _validate_key(self, key, axis: int):
# valid for a collection of labels (we check their presence later)
# slice of labels (where start-end in labels)
# slice of integers (only if in the labels)
# boolean
pass
def _has_valid_setitem_indexer(self, indexer) -> bool:
return True
def _is_scalar_access(self, key: Tuple) -> bool:
"""
Returns
-------
bool
"""
# this is a shortcut accessor to both .loc and .iloc
# that provide the equivalent access of .at and .iat
# a) avoid getting things via sections and (to minimize dtype changes)
# b) provide a performant path
if len(key) != self.ndim:
return False
for i, k in enumerate(key):
if not is_scalar(k):
return False
ax = self.obj.axes[i]
if isinstance(ax, ABCMultiIndex):
return False
if isinstance(k, str) and ax._supports_partial_string_indexing:
# partial string indexing, df.loc['2000', 'A']
# should not be considered scalar
return False
if not ax.is_unique:
return False
return True
# -------------------------------------------------------------------
# MultiIndex Handling
def _multi_take_opportunity(self, tup: Tuple) -> bool:
"""
Check whether there is the possibility to use ``_multi_take``.
Currently the limit is that all axes being indexed, must be indexed with
list-likes.
Parameters
----------
tup : tuple
Tuple of indexers, one per axis.
Returns
-------
bool
Whether the current indexing,
can be passed through `_multi_take`.
"""
if not all(is_list_like_indexer(x) for x in tup):
return False
# just too complicated
if any(com.is_bool_indexer(x) for x in tup):
return False
return True
def _multi_take(self, tup: Tuple):
"""
Create the indexers for the passed tuple of keys, and
executes the take operation. This allows the take operation to be
executed all at once, rather than once for each dimension.
Improving efficiency.
Parameters
----------
tup : tuple
Tuple of indexers, one per axis.
Returns
-------
values: same type as the object being indexed
"""
# GH 836
d = {
axis: self._get_listlike_indexer(key, axis)
for (key, axis) in zip(tup, self.obj._AXIS_ORDERS)
}
return self.obj._reindex_with_indexers(d, copy=True, allow_dups=True)
# -------------------------------------------------------------------
def _getitem_iterable(self, key, axis: int):
"""
Index current object with an an iterable collection of keys.
Parameters
----------
key : iterable
Targeted labels.
axis: int
Dimension on which the indexing is being made.
Raises
------
KeyError
If no key was found. Will change in the future to raise if not all
keys were found.
Returns
-------
scalar, DataFrame, or Series: indexed value(s).
"""
# we assume that not com.is_bool_indexer(key), as that is
# handled before we get here.
self._validate_key(key, axis)
# A collection of keys
keyarr, indexer = self._get_listlike_indexer(key, axis, raise_missing=False)
return self.obj._reindex_with_indexers(
{axis: [keyarr, indexer]}, copy=True, allow_dups=True
)
def _getitem_tuple(self, tup: Tuple):
try:
return self._getitem_lowerdim(tup)
except IndexingError:
pass
# no multi-index, so validate all of the indexers
self._has_valid_tuple(tup)
# ugly hack for GH #836
if self._multi_take_opportunity(tup):
return self._multi_take(tup)
return self._getitem_tuple_same_dim(tup)
def _get_label(self, label, axis: int):
# GH#5667 this will fail if the label is not present in the axis.
return self.obj.xs(label, axis=axis)
def _handle_lowerdim_multi_index_axis0(self, tup: Tuple):
# we have an axis0 multi-index, handle or raise
axis = self.axis or 0
try:
# fast path for series or for tup devoid of slices
return self._get_label(tup, axis=axis)
except TypeError:
# slices are unhashable
pass
except KeyError as ek:
# raise KeyError if number of indexers match
# else IndexingError will be raised
if len(tup) <= self.obj.index.nlevels and len(tup) > self.ndim:
raise ek
return None
def _getitem_axis(self, key, axis: int):
key = item_from_zerodim(key)
if is_iterator(key):
key = list(key)
labels = self.obj._get_axis(axis)
key = labels._get_partial_string_timestamp_match_key(key)
if isinstance(key, slice):
self._validate_key(key, axis)
return self._get_slice_axis(key, axis=axis)
elif com.is_bool_indexer(key):
return self._getbool_axis(key, axis=axis)
elif is_list_like_indexer(key):
# convert various list-like indexers
# to a list of keys
# we will use the *values* of the object
# and NOT the index if its a PandasObject
if isinstance(labels, ABCMultiIndex):
if isinstance(key, (ABCSeries, np.ndarray)) and key.ndim <= 1:
# Series, or 0,1 ndim ndarray
# GH 14730
key = list(key)
elif isinstance(key, ABCDataFrame):
# GH 15438
raise NotImplementedError(
"Indexing a MultiIndex with a "
"DataFrame key is not "
"implemented"
)
elif hasattr(key, "ndim") and key.ndim > 1:
raise NotImplementedError(
"Indexing a MultiIndex with a "
"multidimensional key is not "
"implemented"
)
if (
not isinstance(key, tuple)
and len(key)
and not isinstance(key[0], tuple)
):
key = tuple([key])
# an iterable multi-selection
if not (isinstance(key, tuple) and isinstance(labels, ABCMultiIndex)):
if hasattr(key, "ndim") and key.ndim > 1:
raise ValueError("Cannot index with multidimensional key")
return self._getitem_iterable(key, axis=axis)
# nested tuple slicing
if is_nested_tuple(key, labels):
locs = labels.get_locs(key)
indexer = [slice(None)] * self.ndim
indexer[axis] = locs
return self.obj.iloc[tuple(indexer)]
# fall thru to straight lookup
self._validate_key(key, axis)
return self._get_label(key, axis=axis)
def _get_slice_axis(self, slice_obj: slice, axis: int):
"""
This is pretty simple as we just have to deal with labels.
"""
# caller is responsible for ensuring non-None axis
obj = self.obj
if not need_slice(slice_obj):
return obj.copy(deep=False)
labels = obj._get_axis(axis)
indexer = labels.slice_indexer(
slice_obj.start, slice_obj.stop, slice_obj.step, kind="loc"
)
if isinstance(indexer, slice):
return self.obj._slice(indexer, axis=axis)
else:
# DatetimeIndex overrides Index.slice_indexer and may
# return a DatetimeIndex instead of a slice object.
return self.obj.take(indexer, axis=axis)
def _convert_to_indexer(self, key, axis: int, is_setter: bool = False):
"""
Convert indexing key into something we can use to do actual fancy
indexing on a ndarray.
Examples
ix[:5] -> slice(0, 5)
ix[[1,2,3]] -> [1,2,3]
ix[['foo', 'bar', 'baz']] -> [i, j, k] (indices of foo, bar, baz)
Going by Zen of Python?
'In the face of ambiguity, refuse the temptation to guess.'
raise AmbiguousIndexError with integer labels?
- No, prefer label-based indexing
"""
labels = self.obj._get_axis(axis)
if isinstance(key, slice):
return labels._convert_slice_indexer(key, kind="loc")
# see if we are positional in nature
is_int_index = labels.is_integer()
is_int_positional = is_integer(key) and not is_int_index
if is_scalar(key) or isinstance(labels, ABCMultiIndex):
# Otherwise get_loc will raise InvalidIndexError
# if we are a label return me
try:
return labels.get_loc(key)
except LookupError:
if isinstance(key, tuple) and isinstance(labels, ABCMultiIndex):
if len(key) == labels.nlevels:
return {"key": key}
raise
except TypeError:
pass
except ValueError:
if not is_int_positional:
raise
# a positional
if is_int_positional:
# if we are setting and its not a valid location
# its an insert which fails by definition
# always valid
return {"key": key}
if is_nested_tuple(key, labels):
return labels.get_locs(key)
elif is_list_like_indexer(key):
if com.is_bool_indexer(key):
key = check_bool_indexer(labels, key)
(inds,) = key.nonzero()
return inds
else:
# When setting, missing keys are not allowed, even with .loc:
return self._get_listlike_indexer(key, axis, raise_missing=True)[1]
else:
try:
return labels.get_loc(key)
except LookupError:
# allow a not found key only if we are a setter
if not is_list_like_indexer(key):
return {"key": key}
raise
def _get_listlike_indexer(self, key, axis: int, raise_missing: bool = False):
"""
Transform a list-like of keys into a new index and an indexer.
Parameters
----------
key : list-like
Targeted labels.
axis: int
Dimension on which the indexing is being made.
raise_missing: bool, default False
Whether to raise a KeyError if some labels were not found.
Will be removed in the future, and then this method will always behave as
if ``raise_missing=True``.
Raises
------
KeyError
If at least one key was requested but none was found, and
raise_missing=True.
Returns
-------
keyarr: Index
New index (coinciding with 'key' if the axis is unique).
values : array-like
Indexer for the return object, -1 denotes keys not found.
"""
ax = self.obj._get_axis(axis)
# Have the index compute an indexer or return None
# if it cannot handle:
indexer, keyarr = ax._convert_listlike_indexer(key)
# We only act on all found values:
if indexer is not None and (indexer != -1).all():
self._validate_read_indexer(key, indexer, axis, raise_missing=raise_missing)
return ax[indexer], indexer
if ax.is_unique and not getattr(ax, "is_overlapping", False):
indexer = ax.get_indexer_for(key)
keyarr = ax.reindex(keyarr)[0]
else:
keyarr, indexer, new_indexer = ax._reindex_non_unique(keyarr)
self._validate_read_indexer(keyarr, indexer, axis, raise_missing=raise_missing)
return keyarr, indexer
def _validate_read_indexer(
self, key, indexer, axis: int, raise_missing: bool = False
):
"""
Check that indexer can be used to return a result.
e.g. at least one element was found,
unless the list of keys was actually empty.
Parameters
----------
key : list-like
Targeted labels (only used to show correct error message).
indexer: array-like of booleans
Indices corresponding to the key,
(with -1 indicating not found).
axis: int
Dimension on which the indexing is being made.
raise_missing: bool
Whether to raise a KeyError if some labels are not found. Will be
removed in the future, and then this method will always behave as
if raise_missing=True.
Raises
------
KeyError
If at least one key was requested but none was found, and
raise_missing=True.
"""
ax = self.obj._get_axis(axis)
if len(key) == 0:
return
# Count missing values:
missing = (indexer < 0).sum()
if missing:
if missing == len(indexer):
axis_name = self.obj._get_axis_name(axis)
raise KeyError(f"None of [{key}] are in the [{axis_name}]")
# We (temporarily) allow for some missing keys with .loc, except in
# some cases (e.g. setting) in which "raise_missing" will be False
if raise_missing:
not_found = list(set(key) - set(ax))
raise KeyError(f"{not_found} not in index")
# we skip the warning on Categorical
# as this check is actually done (check for
# non-missing values), but a bit later in the
# code, so we want to avoid warning & then
# just raising
if not ax.is_categorical():
raise KeyError(
"Passing list-likes to .loc or [] with any missing labels "
"is no longer supported, see "
"https://pandas.pydata.org/pandas-docs/stable/user_guide/indexing.html#deprecate-loc-reindex-listlike" # noqa:E501
)
@doc(IndexingMixin.iloc)
class _iLocIndexer(_LocationIndexer):
_valid_types = (
"integer, integer slice (START point is INCLUDED, END "
"point is EXCLUDED), listlike of integers, boolean array"
)
_takeable = True
# -------------------------------------------------------------------
# Key Checks
def _validate_key(self, key, axis: int):
if com.is_bool_indexer(key):
if hasattr(key, "index") and isinstance(key.index, Index):
if key.index.inferred_type == "integer":
raise NotImplementedError(
"iLocation based boolean "
"indexing on an integer type "
"is not available"
)
raise ValueError(
"iLocation based boolean indexing cannot use "
"an indexable as a mask"
)
return
if isinstance(key, slice):
return
elif is_integer(key):
self._validate_integer(key, axis)
elif isinstance(key, tuple):
# a tuple should already have been caught by this point
# so don't treat a tuple as a valid indexer
raise IndexingError("Too many indexers")
elif is_list_like_indexer(key):
arr = np.array(key)
len_axis = len(self.obj._get_axis(axis))
# check that the key has a numeric dtype
if not is_numeric_dtype(arr.dtype):
raise IndexError(f".iloc requires numeric indexers, got {arr}")
# check that the key does not exceed the maximum size of the index
if len(arr) and (arr.max() >= len_axis or arr.min() < -len_axis):
raise IndexError("positional indexers are out-of-bounds")
else:
raise ValueError(f"Can only index by location with a [{self._valid_types}]")
def _has_valid_setitem_indexer(self, indexer) -> bool:
"""
Validate that a positional indexer cannot enlarge its target
will raise if needed, does not modify the indexer externally.
Returns
-------
bool
"""
if isinstance(indexer, dict):
raise IndexError("iloc cannot enlarge its target object")
else:
if not isinstance(indexer, tuple):
indexer = _tuplify(self.ndim, indexer)
for ax, i in zip(self.obj.axes, indexer):
if isinstance(i, slice):
# should check the stop slice?
pass
elif is_list_like_indexer(i):
# should check the elements?
pass
elif is_integer(i):
if i >= len(ax):
raise IndexError("iloc cannot enlarge its target object")
elif isinstance(i, dict):
raise IndexError("iloc cannot enlarge its target object")
return True
def _is_scalar_access(self, key: Tuple) -> bool:
"""
Returns
-------
bool
"""
# this is a shortcut accessor to both .loc and .iloc
# that provide the equivalent access of .at and .iat
# a) avoid getting things via sections and (to minimize dtype changes)
# b) provide a performant path
if len(key) != self.ndim:
return False
for k in key:
if not is_integer(k):
return False
return True
def _validate_integer(self, key: int, axis: int) -> None:
"""
Check that 'key' is a valid position in the desired axis.
Parameters
----------
key : int
Requested position.
axis : int
Desired axis.
Raises
------
IndexError
If 'key' is not a valid position in axis 'axis'.
"""
len_axis = len(self.obj._get_axis(axis))
if key >= len_axis or key < -len_axis:
raise IndexError("single positional indexer is out-of-bounds")
# -------------------------------------------------------------------
def _getitem_tuple(self, tup: Tuple):
self._has_valid_tuple(tup)
try:
return self._getitem_lowerdim(tup)
except IndexingError:
pass
return self._getitem_tuple_same_dim(tup)
def _get_list_axis(self, key, axis: int):
"""
Return Series values by list or array of integers.
Parameters
----------
key : list-like positional indexer
axis : int
Returns
-------
Series object
Notes
-----
`axis` can only be zero.
"""
try:
return self.obj._take_with_is_copy(key, axis=axis)
except IndexError as err:
# re-raise with different error message
raise IndexError("positional indexers are out-of-bounds") from err
def _getitem_axis(self, key, axis: int):
if isinstance(key, slice):
return self._get_slice_axis(key, axis=axis)
if isinstance(key, list):
key = np.asarray(key)
if com.is_bool_indexer(key):
self._validate_key(key, axis)
return self._getbool_axis(key, axis=axis)
# a list of integers
elif is_list_like_indexer(key):
return self._get_list_axis(key, axis=axis)
# a single integer
else:
key = item_from_zerodim(key)
if not is_integer(key):
raise TypeError("Cannot index by location index with a non-integer key")
# validate the location
self._validate_integer(key, axis)
return self.obj._ixs(key, axis=axis)
def _get_slice_axis(self, slice_obj: slice, axis: int):
# caller is responsible for ensuring non-None axis
obj = self.obj
if not need_slice(slice_obj):
return obj.copy(deep=False)
labels = obj._get_axis(axis)
labels._validate_positional_slice(slice_obj)
return self.obj._slice(slice_obj, axis=axis)
def _convert_to_indexer(self, key, axis: int, is_setter: bool = False):
"""
Much simpler as we only have to deal with our valid types.
"""
return key
def _get_setitem_indexer(self, key):
# GH#32257 Fall through to let numnpy do validation
return key
# -------------------------------------------------------------------
def _setitem_with_indexer(self, indexer, value):
"""
_setitem_with_indexer is for setting values on a Series/DataFrame
using positional indexers.
If the relevant keys are not present, the Series/DataFrame may be
expanded.
This method is currently broken when dealing with non-unique Indexes,
since it goes from positional indexers back to labels when calling
BlockManager methods, see GH#12991, GH#22046, GH#15686.
"""
# also has the side effect of consolidating in-place
from pandas import Series
info_axis = self.obj._info_axis_number
# maybe partial set
take_split_path = self.obj._is_mixed_type
# if there is only one block/type, still have to take split path
# unless the block is one-dimensional or it can hold the value
if not take_split_path and self.obj._mgr.blocks:
(blk,) = self.obj._mgr.blocks
if 1 < blk.ndim: # in case of dict, keys are indices
val = list(value.values()) if isinstance(value, dict) else value
take_split_path = not blk._can_hold_element(val)
# if we have any multi-indexes that have non-trivial slices
# (not null slices) then we must take the split path, xref
# GH 10360, GH 27841
if isinstance(indexer, tuple) and len(indexer) == len(self.obj.axes):
for i, ax in zip(indexer, self.obj.axes):
if isinstance(ax, ABCMultiIndex) and not (
is_integer(i) or com.is_null_slice(i)
):
take_split_path = True
break
if isinstance(indexer, tuple):
nindexer = []
for i, idx in enumerate(indexer):
if isinstance(idx, dict):
# reindex the axis to the new value
# and set inplace
key, _ = convert_missing_indexer(idx)
# if this is the items axes, then take the main missing
# path first
# this correctly sets the dtype and avoids cache issues
# essentially this separates out the block that is needed
# to possibly be modified
if self.ndim > 1 and i == info_axis:
# add the new item, and set the value
# must have all defined axes if we have a scalar
# or a list-like on the non-info axes if we have a
# list-like
len_non_info_axes = (
len(_ax) for _i, _ax in enumerate(self.obj.axes) if _i != i
)
if any(not l for l in len_non_info_axes):
if not is_list_like_indexer(value):
raise ValueError(
"cannot set a frame with no "
"defined index and a scalar"
)
self.obj[key] = value
return
# add a new item with the dtype setup
self.obj[key] = _infer_fill_value(value)
new_indexer = convert_from_missing_indexer_tuple(
indexer, self.obj.axes
)
self._setitem_with_indexer(new_indexer, value)
return
# reindex the axis
# make sure to clear the cache because we are
# just replacing the block manager here
# so the object is the same
index = self.obj._get_axis(i)
labels = index.insert(len(index), key)
self.obj._mgr = self.obj.reindex(labels, axis=i)._mgr
self.obj._maybe_update_cacher(clear=True)
self.obj._is_copy = None
nindexer.append(labels.get_loc(key))
else:
nindexer.append(idx)
indexer = tuple(nindexer)
else:
indexer, missing = convert_missing_indexer(indexer)
if missing:
self._setitem_with_indexer_missing(indexer, value)
return
# set
item_labels = self.obj._get_axis(info_axis)
# align and set the values
if take_split_path:
# Above we only set take_split_path to True for 2D cases
assert self.ndim == 2
assert info_axis == 1
if not isinstance(indexer, tuple):
indexer = _tuplify(self.ndim, indexer)
if isinstance(value, ABCSeries):
value = self._align_series(indexer, value)
info_idx = indexer[info_axis]
if is_integer(info_idx):
info_idx = [info_idx]
labels = item_labels[info_idx]
# Ensure we have something we can iterate over
ilocs = info_idx
if isinstance(info_idx, slice):
ri = Index(range(len(self.obj.columns)))
ilocs = ri[info_idx]
plane_indexer = indexer[:1]
lplane_indexer = length_of_indexer(plane_indexer[0], self.obj.index)
# lplane_indexer gives the expected length of obj[indexer[0]]
if len(labels) == 1:
# We can operate on a single column
# require that we are setting the right number of values that
# we are indexing
if is_list_like_indexer(value) and 0 != lplane_indexer != len(value):
# Exclude zero-len for e.g. boolean masking that is all-false
raise ValueError(
"cannot set using a multi-index "
"selection indexer with a different "
"length than the value"
)
pi = plane_indexer[0] if lplane_indexer == 1 else plane_indexer
def isetter(loc, v):
# positional setting on column loc
ser = self.obj._ixs(loc, axis=1)
# perform the equivalent of a setitem on the info axis
# as we have a null slice or a slice with full bounds
# which means essentially reassign to the columns of a
# multi-dim object
# GH6149 (null slice), GH10408 (full bounds)
if isinstance(pi, tuple) and all(
com.is_null_slice(idx) or com.is_full_slice(idx, len(self.obj))
for idx in pi
):
ser = v
else:
# set the item, possibly having a dtype change
ser._consolidate_inplace()
ser = ser.copy()
ser._mgr = ser._mgr.setitem(indexer=pi, value=v)
ser._maybe_update_cacher(clear=True)
# reset the sliced object if unique
self.obj._iset_item(loc, ser)
# we need an iterable, with a ndim of at least 1
# eg. don't pass through np.array(0)
if is_list_like_indexer(value) and getattr(value, "ndim", 1) > 0:
# we have an equal len Frame
if isinstance(value, ABCDataFrame):
sub_indexer = list(indexer)
multiindex_indexer = isinstance(labels, ABCMultiIndex)
# TODO: we are implicitly assuming value.columns is unique
for loc in ilocs:
item = item_labels[loc]
if item in value:
sub_indexer[info_axis] = item
v = self._align_series(
tuple(sub_indexer), value[item], multiindex_indexer
)
else:
v = np.nan
isetter(loc, v)
# we have an equal len ndarray/convertible to our labels
# hasattr first, to avoid coercing to ndarray without reason.
# But we may be relying on the ndarray coercion to check ndim.
# Why not just convert to an ndarray earlier on if needed?
elif np.ndim(value) == 2:
# note that this coerces the dtype if we are mixed
# GH 7551
value = np.array(value, dtype=object)
if len(ilocs) != value.shape[1]:
raise ValueError(
"Must have equal len keys and value "
"when setting with an ndarray"
)
for i, loc in enumerate(ilocs):
# setting with a list, re-coerces
isetter(loc, value[:, i].tolist())
elif (
len(labels) == 1
and lplane_indexer == len(value)
and not is_scalar(plane_indexer[0])
):
# we have an equal len list/ndarray
# We only get here with len(labels) == len(ilocs) == 1
isetter(ilocs[0], value)
elif lplane_indexer == 0 and len(value) == len(self.obj.index):
# We get here in one case via .loc with a all-False mask
pass
else:
# per-label values
if len(ilocs) != len(value):
raise ValueError(
"Must have equal len keys and value "
"when setting with an iterable"
)
for loc, v in zip(ilocs, value):
isetter(loc, v)
else:
# scalar value
for loc in ilocs:
isetter(loc, value)
else:
if isinstance(indexer, tuple):
# if we are setting on the info axis ONLY
# set using those methods to avoid block-splitting
# logic here
if (
len(indexer) > info_axis
and is_integer(indexer[info_axis])
and all(
com.is_null_slice(idx)
for i, idx in enumerate(indexer)
if i != info_axis
)
and item_labels.is_unique
):
self.obj[item_labels[indexer[info_axis]]] = value
return
indexer = maybe_convert_ix(*indexer)
if isinstance(value, (ABCSeries, dict)):
# TODO(EA): ExtensionBlock.setitem this causes issues with
# setting for extensionarrays that store dicts. Need to decide
# if it's worth supporting that.
value = self._align_series(indexer, Series(value))
elif isinstance(value, ABCDataFrame):
value = self._align_frame(indexer, value)
# check for chained assignment
self.obj._check_is_chained_assignment_possible()
# actually do the set
self.obj._consolidate_inplace()
self.obj._mgr = self.obj._mgr.setitem(indexer=indexer, value=value)
self.obj._maybe_update_cacher(clear=True)
def _setitem_with_indexer_missing(self, indexer, value):
"""
Insert new row(s) or column(s) into the Series or DataFrame.
"""
from pandas import Series
# reindex the axis to the new value
# and set inplace
if self.ndim == 1:
index = self.obj.index
new_index = index.insert(len(index), indexer)
# we have a coerced indexer, e.g. a float
# that matches in an Int64Index, so
# we will not create a duplicate index, rather
# index to that element
# e.g. 0.0 -> 0
# GH#12246
if index.is_unique:
new_indexer = index.get_indexer([new_index[-1]])
if (new_indexer != -1).any():
return self._setitem_with_indexer(new_indexer, value)
# this preserves dtype of the value
new_values = Series([value])._values
if len(self.obj._values):
# GH#22717 handle casting compatibility that np.concatenate
# does incorrectly
new_values = concat_compat([self.obj._values, new_values])
self.obj._mgr = self.obj._constructor(
new_values, index=new_index, name=self.obj.name
)._mgr
self.obj._maybe_update_cacher(clear=True)
elif self.ndim == 2:
if not len(self.obj.columns):
# no columns and scalar
raise ValueError("cannot set a frame with no defined columns")
if isinstance(value, ABCSeries):
# append a Series
value = value.reindex(index=self.obj.columns, copy=True)
value.name = indexer
else:
# a list-list
if is_list_like_indexer(value):
# must have conforming columns
if len(value) != len(self.obj.columns):
raise ValueError("cannot set a row with mismatched columns")
value = Series(value, index=self.obj.columns, name=indexer)
self.obj._mgr = self.obj.append(value)._mgr
self.obj._maybe_update_cacher(clear=True)
def _align_series(self, indexer, ser: ABCSeries, multiindex_indexer: bool = False):
"""
Parameters
----------
indexer : tuple, slice, scalar
Indexer used to get the locations that will be set to `ser`.
ser : pd.Series
Values to assign to the locations specified by `indexer`.
multiindex_indexer : boolean, optional
Defaults to False. Should be set to True if `indexer` was from
a `pd.MultiIndex`, to avoid unnecessary broadcasting.
Returns
-------
`np.array` of `ser` broadcast to the appropriate shape for assignment
to the locations selected by `indexer`
"""
if isinstance(indexer, (slice, np.ndarray, list, Index)):
indexer = tuple([indexer])
if isinstance(indexer, tuple):
# flatten np.ndarray indexers
def ravel(i):
return i.ravel() if isinstance(i, np.ndarray) else i
indexer = tuple(map(ravel, indexer))
aligners = [not com.is_null_slice(idx) for idx in indexer]
sum_aligners = sum(aligners)
single_aligner = sum_aligners == 1
is_frame = self.ndim == 2
obj = self.obj
# are we a single alignable value on a non-primary
# dim (e.g. panel: 1,2, or frame: 0) ?
# hence need to align to a single axis dimension
# rather that find all valid dims
# frame
if is_frame:
single_aligner = single_aligner and aligners[0]
# we have a frame, with multiple indexers on both axes; and a
# series, so need to broadcast (see GH5206)
if sum_aligners == self.ndim and all(is_sequence(_) for _ in indexer):
ser = ser.reindex(obj.axes[0][indexer[0]], copy=True)._values
# single indexer
if len(indexer) > 1 and not multiindex_indexer:
len_indexer = len(indexer[1])
ser = np.tile(ser, len_indexer).reshape(len_indexer, -1).T
return ser
for i, idx in enumerate(indexer):
ax = obj.axes[i]
# multiple aligners (or null slices)
if is_sequence(idx) or isinstance(idx, slice):
if single_aligner and com.is_null_slice(idx):
continue
new_ix = ax[idx]
if not is_list_like_indexer(new_ix):
new_ix = Index([new_ix])
else:
new_ix = Index(new_ix)
if ser.index.equals(new_ix) or not len(new_ix):
return ser._values.copy()
return ser.reindex(new_ix)._values
# 2 dims
elif single_aligner:
# reindex along index
ax = self.obj.axes[1]
if ser.index.equals(ax) or not len(ax):
return ser._values.copy()
return ser.reindex(ax)._values
elif is_scalar(indexer):
ax = self.obj._get_axis(1)
if ser.index.equals(ax):
return ser._values.copy()
return ser.reindex(ax)._values
raise ValueError("Incompatible indexer with Series")
def _align_frame(self, indexer, df: ABCDataFrame):
is_frame = self.ndim == 2
if isinstance(indexer, tuple):
idx, cols = None, None
sindexers = []
for i, ix in enumerate(indexer):
ax = self.obj.axes[i]
if is_sequence(ix) or isinstance(ix, slice):
if isinstance(ix, np.ndarray):
ix = ix.ravel()
if idx is None:
idx = ax[ix]
elif cols is None:
cols = ax[ix]
else:
break
else:
sindexers.append(i)
if idx is not None and cols is not None:
if df.index.equals(idx) and df.columns.equals(cols):
val = df.copy()._values
else:
val = df.reindex(idx, columns=cols)._values
return val
elif (isinstance(indexer, slice) or is_list_like_indexer(indexer)) and is_frame:
ax = self.obj.index[indexer]
if df.index.equals(ax):
val = df.copy()._values
else:
# we have a multi-index and are trying to align
# with a particular, level GH3738
if (
isinstance(ax, ABCMultiIndex)
and isinstance(df.index, ABCMultiIndex)
and ax.nlevels != df.index.nlevels
):
raise TypeError(
"cannot align on a multi-index with out "
"specifying the join levels"
)
val = df.reindex(index=ax)._values
return val
raise ValueError("Incompatible indexer with DataFrame")
class _ScalarAccessIndexer(_NDFrameIndexerBase):
"""
Access scalars quickly.
"""
def _convert_key(self, key, is_setter: bool = False):
raise AbstractMethodError(self)
def __getitem__(self, key):
if not isinstance(key, tuple):
# we could have a convertible item here (e.g. Timestamp)
if not is_list_like_indexer(key):
key = tuple([key])
else:
raise ValueError("Invalid call for scalar access (getting)!")
key = self._convert_key(key)
return self.obj._get_value(*key, takeable=self._takeable)
def __setitem__(self, key, value):
if isinstance(key, tuple):
key = tuple(com.apply_if_callable(x, self.obj) for x in key)
else:
# scalar callable may return tuple
key = com.apply_if_callable(key, self.obj)
if not isinstance(key, tuple):
key = _tuplify(self.ndim, key)
if len(key) != self.ndim:
raise ValueError("Not enough indexers for scalar access (setting)!")
key = list(self._convert_key(key, is_setter=True))
self.obj._set_value(*key, value=value, takeable=self._takeable)
@doc(IndexingMixin.at)
class _AtIndexer(_ScalarAccessIndexer):
_takeable = False
def _convert_key(self, key, is_setter: bool = False):
"""
Require they keys to be the same type as the index. (so we don't
fallback)
"""
# allow arbitrary setting
if is_setter:
return list(key)
return key
@property
def _axes_are_unique(self) -> bool:
# Only relevant for self.ndim == 2
assert self.ndim == 2
return self.obj.index.is_unique and self.obj.columns.is_unique
def __getitem__(self, key):
if self.ndim == 2 and not self._axes_are_unique:
# GH#33041 fall back to .loc
if not isinstance(key, tuple) or not all(is_scalar(x) for x in key):
raise ValueError("Invalid call for scalar access (getting)!")
return self.obj.loc[key]
return super().__getitem__(key)
def __setitem__(self, key, value):
if self.ndim == 2 and not self._axes_are_unique:
# GH#33041 fall back to .loc
if not isinstance(key, tuple) or not all(is_scalar(x) for x in key):
raise ValueError("Invalid call for scalar access (setting)!")
self.obj.loc[key] = value
return
return super().__setitem__(key, value)
@doc(IndexingMixin.iat)
class _iAtIndexer(_ScalarAccessIndexer):
_takeable = True
def _convert_key(self, key, is_setter: bool = False):
"""
Require integer args. (and convert to label arguments)
"""
for a, i in zip(self.obj.axes, key):
if not is_integer(i):
raise ValueError("iAt based indexing can only have integer indexers")
return key
def _tuplify(ndim: int, loc: Hashable) -> Tuple[Union[Hashable, slice], ...]:
"""
Given an indexer for the first dimension, create an equivalent tuple
for indexing over all dimensions.
Parameters
----------
ndim : int
loc : object
Returns
-------
tuple
"""
_tup: List[Union[Hashable, slice]]
_tup = [slice(None, None) for _ in range(ndim)]
_tup[0] = loc
return tuple(_tup)
def convert_to_index_sliceable(obj: "DataFrame", key):
"""
If we are index sliceable, then return my slicer, otherwise return None.
"""
idx = obj.index
if isinstance(key, slice):
return idx._convert_slice_indexer(key, kind="getitem")
elif isinstance(key, str):
# we are an actual column
if key in obj.columns:
return None
# We might have a datetimelike string that we can translate to a
# slice here via partial string indexing
if idx._supports_partial_string_indexing:
try:
return idx._get_string_slice(key)
except (KeyError, ValueError, NotImplementedError):
return None
return None
def check_bool_indexer(index: Index, key) -> np.ndarray:
"""
Check if key is a valid boolean indexer for an object with such index and
perform reindexing or conversion if needed.
This function assumes that is_bool_indexer(key) == True.
Parameters
----------
index : Index
Index of the object on which the indexing is done.
key : list-like
Boolean indexer to check.
Returns
-------
np.array
Resulting key.
Raises
------
IndexError
If the key does not have the same length as index.
IndexingError
If the index of the key is unalignable to index.
"""
result = key
if isinstance(key, ABCSeries) and not key.index.equals(index):
result = result.reindex(index)
mask = isna(result._values)
if mask.any():
raise IndexingError(
"Unalignable boolean Series provided as "
"indexer (index of the boolean Series and of "
"the indexed object do not match)."
)
result = result.astype(bool)._values
elif is_object_dtype(key):
# key might be object-dtype bool, check_array_indexer needs bool array
result = np.asarray(result, dtype=bool)
result = check_array_indexer(index, result)
else:
result = check_array_indexer(index, result)
return result
def convert_missing_indexer(indexer):
"""
Reverse convert a missing indexer, which is a dict
return the scalar indexer and a boolean indicating if we converted
"""
if isinstance(indexer, dict):
# a missing key (but not a tuple indexer)
indexer = indexer["key"]
if isinstance(indexer, bool):
raise KeyError("cannot use a single bool to index into setitem")
return indexer, True
return indexer, False
def convert_from_missing_indexer_tuple(indexer, axes):
"""
Create a filtered indexer that doesn't have any missing indexers.
"""
def get_indexer(_i, _idx):
return axes[_i].get_loc(_idx["key"]) if isinstance(_idx, dict) else _idx
return tuple(get_indexer(_i, _idx) for _i, _idx in enumerate(indexer))
def maybe_convert_ix(*args):
"""
We likely want to take the cross-product.
"""
ixify = True
for arg in args:
if not isinstance(arg, (np.ndarray, list, ABCSeries, Index)):
ixify = False
if ixify:
return np.ix_(*args)
else:
return args
def is_nested_tuple(tup, labels) -> bool:
"""
Returns
-------
bool
"""
# check for a compatible nested tuple and multiindexes among the axes
if not isinstance(tup, tuple):
return False
for k in tup:
if is_list_like(k) or isinstance(k, slice):
return isinstance(labels, ABCMultiIndex)
return False
def is_label_like(key) -> bool:
"""
Returns
-------
bool
"""
# select a label or row
return not isinstance(key, slice) and not is_list_like_indexer(key)
def need_slice(obj) -> bool:
"""
Returns
-------
bool
"""
return (
obj.start is not None
or obj.stop is not None
or (obj.step is not None and obj.step != 1)
)
def _non_reducing_slice(slice_):
"""
Ensurse that a slice doesn't reduce to a Series or Scalar.
Any user-paseed `subset` should have this called on it
to make sure we're always working with DataFrames.
"""
# default to column slice, like DataFrame
# ['A', 'B'] -> IndexSlices[:, ['A', 'B']]
kinds = (ABCSeries, np.ndarray, Index, list, str)
if isinstance(slice_, kinds):
slice_ = IndexSlice[:, slice_]
def pred(part) -> bool:
"""
Returns
-------
bool
True if slice does *not* reduce,
False if `part` is a tuple.
"""
# true when slice does *not* reduce, False when part is a tuple,
# i.e. MultiIndex slice
return (isinstance(part, slice) or is_list_like(part)) and not isinstance(
part, tuple
)
if not is_list_like(slice_):
if not isinstance(slice_, slice):
# a 1-d slice, like df.loc[1]
slice_ = [[slice_]]
else:
# slice(a, b, c)
slice_ = [slice_] # to tuplize later
else:
slice_ = [part if pred(part) else [part] for part in slice_]
return tuple(slice_)
def _maybe_numeric_slice(df, slice_, include_bool=False):
"""
Want nice defaults for background_gradient that don't break
with non-numeric data. But if slice_ is passed go with that.
"""
if slice_ is None:
dtypes = [np.number]
if include_bool:
dtypes.append(bool)
slice_ = IndexSlice[:, df.select_dtypes(include=dtypes).columns]
return slice_
from typing import TYPE_CHECKING, Hashable, List, Tuple, Union
import numpy as np
from pandas._libs.indexing import _NDFrameIndexerBase
from pandas._libs.lib import item_from_zerodim
from pandas.errors import AbstractMethodError
from pandas.util._decorators import doc
from pandas.core.dtypes.common import (
is_hashable,
is_integer,
is_iterator,
is_list_like,
is_numeric_dtype,
is_object_dtype,
is_scalar,
is_sequence,
)
from pandas.core.dtypes.concat import concat_compat
from pandas.core.dtypes.generic import ABCDataFrame, ABCMultiIndex, ABCSeries
from pandas.core.dtypes.missing import _infer_fill_value, isna
import pandas.core.common as com
from pandas.core.indexers import (
check_array_indexer,
is_list_like_indexer,
length_of_indexer,
)
from pandas.core.indexes.api import Index, InvalidIndexError
if TYPE_CHECKING:
from pandas import DataFrame # noqa:F401
# "null slice"
_NS = slice(None, None)
# the public IndexSlicerMaker
class _IndexSlice:
"""
Create an object to more easily perform multi-index slicing.
See Also
--------
MultiIndex.remove_unused_levels : New MultiIndex with no unused levels.
Notes
-----
See :ref:`Defined Levels <advanced.shown_levels>`
for further info on slicing a MultiIndex.
Examples
--------
>>> midx = pd.MultiIndex.from_product([['A0','A1'], ['B0','B1','B2','B3']])
>>> columns = ['foo', 'bar']
>>> dfmi = pd.DataFrame(np.arange(16).reshape((len(midx), len(columns))),
index=midx, columns=columns)
Using the default slice command:
>>> dfmi.loc[(slice(None), slice('B0', 'B1')), :]
foo bar
A0 B0 0 1
B1 2 3
A1 B0 8 9
B1 10 11
Using the IndexSlice class for a more intuitive command:
>>> idx = pd.IndexSlice
>>> dfmi.loc[idx[:, 'B0':'B1'], :]
foo bar
A0 B0 0 1
B1 2 3
A1 B0 8 9
B1 10 11
"""
def __getitem__(self, arg):
return arg
IndexSlice = _IndexSlice()
class IndexingError(Exception):
pass
class IndexingMixin:
"""
Mixin for adding .loc/.iloc/.at/.iat to Datafames and Series.
"""
@property
def iloc(self) -> "_iLocIndexer":
"""
Purely integer-location based indexing for selection by position.
``.iloc[]`` is primarily integer position based (from ``0`` to
``length-1`` of the axis), but may also be used with a boolean
array.
Allowed inputs are:
- An integer, e.g. ``5``.
- A list or array of integers, e.g. ``[4, 3, 0]``.
- A slice object with ints, e.g. ``1:7``.
- A boolean array.
- A ``callable`` function with one argument (the calling Series or
DataFrame) and that returns valid output for indexing (one of the above).
This is useful in method chains, when you don't have a reference to the
calling object, but would like to base your selection on some value.
``.iloc`` will raise ``IndexError`` if a requested indexer is
out-of-bounds, except *slice* indexers which allow out-of-bounds
indexing (this conforms with python/numpy *slice* semantics).
See more at :ref:`Selection by Position <indexing.integer>`.
See Also
--------
DataFrame.iat : Fast integer location scalar accessor.
DataFrame.loc : Purely label-location based indexer for selection by label.
Series.iloc : Purely integer-location based indexing for
selection by position.
Examples
--------
>>> mydict = [{'a': 1, 'b': 2, 'c': 3, 'd': 4},
... {'a': 100, 'b': 200, 'c': 300, 'd': 400},
... {'a': 1000, 'b': 2000, 'c': 3000, 'd': 4000 }]
>>> df = pd.DataFrame(mydict)
>>> df
a b c d
0 1 2 3 4
1 100 200 300 400
2 1000 2000 3000 4000
**Indexing just the rows**
With a scalar integer.
>>> type(df.iloc[0])
<class 'pandas.core.series.Series'>
>>> df.iloc[0]
a 1
b 2
c 3
d 4
Name: 0, dtype: int64
With a list of integers.
>>> df.iloc[[0]]
a b c d
0 1 2 3 4
>>> type(df.iloc[[0]])
<class 'pandas.core.frame.DataFrame'>
>>> df.iloc[[0, 1]]
a b c d
0 1 2 3 4
1 100 200 300 400
With a `slice` object.
>>> df.iloc[:3]
a b c d
0 1 2 3 4
1 100 200 300 400
2 1000 2000 3000 4000
With a boolean mask the same length as the index.
>>> df.iloc[[True, False, True]]
a b c d
0 1 2 3 4
2 1000 2000 3000 4000
With a callable, useful in method chains. The `x` passed
to the ``lambda`` is the DataFrame being sliced. This selects
the rows whose index label even.
>>> df.iloc[lambda x: x.index % 2 == 0]
a b c d
0 1 2 3 4
2 1000 2000 3000 4000
**Indexing both axes**
You can mix the indexer types for the index and columns. Use ``:`` to
select the entire axis.
With scalar integers.
>>> df.iloc[0, 1]
2
With lists of integers.
>>> df.iloc[[0, 2], [1, 3]]
b d
0 2 4
2 2000 4000
With `slice` objects.
>>> df.iloc[1:3, 0:3]
a b c
1 100 200 300
2 1000 2000 3000
With a boolean array whose length matches the columns.
>>> df.iloc[:, [True, False, True, False]]
a c
0 1 3
1 100 300
2 1000 3000
With a callable function that expects the Series or DataFrame.
>>> df.iloc[:, lambda df: [0, 2]]
a c
0 1 3
1 100 300
2 1000 3000
"""
return _iLocIndexer("iloc", self)
@property
def loc(self) -> "_LocIndexer":
"""
Access a group of rows and columns by label(s) or a boolean array.
``.loc[]`` is primarily label based, but may also be used with a
boolean array.
Allowed inputs are:
- A single label, e.g. ``5`` or ``'a'``, (note that ``5`` is
interpreted as a *label* of the index, and **never** as an
integer position along the index).
- A list or array of labels, e.g. ``['a', 'b', 'c']``.
- A slice object with labels, e.g. ``'a':'f'``.
.. warning:: Note that contrary to usual python slices, **both** the
start and the stop are included
- A boolean array of the same length as the axis being sliced,
e.g. ``[True, False, True]``.
- A ``callable`` function with one argument (the calling Series or
DataFrame) and that returns valid output for indexing (one of the above)
See more at :ref:`Selection by Label <indexing.label>`
Raises
------
KeyError
If any items are not found.
See Also
--------
DataFrame.at : Access a single value for a row/column label pair.
DataFrame.iloc : Access group of rows and columns by integer position(s).
DataFrame.xs : Returns a cross-section (row(s) or column(s)) from the
Series/DataFrame.
Series.loc : Access group of values using labels.
Examples
--------
**Getting values**
>>> df = pd.DataFrame([[1, 2], [4, 5], [7, 8]],
... index=['cobra', 'viper', 'sidewinder'],
... columns=['max_speed', 'shield'])
>>> df
max_speed shield
cobra 1 2
viper 4 5
sidewinder 7 8
Single label. Note this returns the row as a Series.
>>> df.loc['viper']
max_speed 4
shield 5
Name: viper, dtype: int64
List of labels. Note using ``[[]]`` returns a DataFrame.
>>> df.loc[['viper', 'sidewinder']]
max_speed shield
viper 4 5
sidewinder 7 8
Single label for row and column
>>> df.loc['cobra', 'shield']
2
Slice with labels for row and single label for column. As mentioned
above, note that both the start and stop of the slice are included.
>>> df.loc['cobra':'viper', 'max_speed']
cobra 1
viper 4
Name: max_speed, dtype: int64
Boolean list with the same length as the row axis
>>> df.loc[[False, False, True]]
max_speed shield
sidewinder 7 8
Conditional that returns a boolean Series
>>> df.loc[df['shield'] > 6]
max_speed shield
sidewinder 7 8
Conditional that returns a boolean Series with column labels specified
>>> df.loc[df['shield'] > 6, ['max_speed']]
max_speed
sidewinder 7
Callable that returns a boolean Series
>>> df.loc[lambda df: df['shield'] == 8]
max_speed shield
sidewinder 7 8
**Setting values**
Set value for all items matching the list of labels
>>> df.loc[['viper', 'sidewinder'], ['shield']] = 50
>>> df
max_speed shield
cobra 1 2
viper 4 50
sidewinder 7 50
Set value for an entire row
>>> df.loc['cobra'] = 10
>>> df
max_speed shield
cobra 10 10
viper 4 50
sidewinder 7 50
Set value for an entire column
>>> df.loc[:, 'max_speed'] = 30
>>> df
max_speed shield
cobra 30 10
viper 30 50
sidewinder 30 50
Set value for rows matching callable condition
>>> df.loc[df['shield'] > 35] = 0
>>> df
max_speed shield
cobra 30 10
viper 0 0
sidewinder 0 0
**Getting values on a DataFrame with an index that has integer labels**
Another example using integers for the index
>>> df = pd.DataFrame([[1, 2], [4, 5], [7, 8]],
... index=[7, 8, 9], columns=['max_speed', 'shield'])
>>> df
max_speed shield
7 1 2
8 4 5
9 7 8
Slice with integer labels for rows. As mentioned above, note that both
the start and stop of the slice are included.
>>> df.loc[7:9]
max_speed shield
7 1 2
8 4 5
9 7 8
**Getting values with a MultiIndex**
A number of examples using a DataFrame with a MultiIndex
>>> tuples = [
... ('cobra', 'mark i'), ('cobra', 'mark ii'),
... ('sidewinder', 'mark i'), ('sidewinder', 'mark ii'),
... ('viper', 'mark ii'), ('viper', 'mark iii')
... ]
>>> index = pd.MultiIndex.from_tuples(tuples)
>>> values = [[12, 2], [0, 4], [10, 20],
... [1, 4], [7, 1], [16, 36]]
>>> df = pd.DataFrame(values, columns=['max_speed', 'shield'], index=index)
>>> df
max_speed shield
cobra mark i 12 2
mark ii 0 4
sidewinder mark i 10 20
mark ii 1 4
viper mark ii 7 1
mark iii 16 36
Single label. Note this returns a DataFrame with a single index.
>>> df.loc['cobra']
max_speed shield
mark i 12 2
mark ii 0 4
Single index tuple. Note this returns a Series.
>>> df.loc[('cobra', 'mark ii')]
max_speed 0
shield 4
Name: (cobra, mark ii), dtype: int64
Single label for row and column. Similar to passing in a tuple, this
returns a Series.
>>> df.loc['cobra', 'mark i']
max_speed 12
shield 2
Name: (cobra, mark i), dtype: int64
Single tuple. Note using ``[[]]`` returns a DataFrame.
>>> df.loc[[('cobra', 'mark ii')]]
max_speed shield
cobra mark ii 0 4
Single tuple for the index with a single label for the column
>>> df.loc[('cobra', 'mark i'), 'shield']
2
Slice from index tuple to single label
>>> df.loc[('cobra', 'mark i'):'viper']
max_speed shield
cobra mark i 12 2
mark ii 0 4
sidewinder mark i 10 20
mark ii 1 4
viper mark ii 7 1
mark iii 16 36
Slice from index tuple to index tuple
>>> df.loc[('cobra', 'mark i'):('viper', 'mark ii')]
max_speed shield
cobra mark i 12 2
mark ii 0 4
sidewinder mark i 10 20
mark ii 1 4
viper mark ii 7 1
"""
return _LocIndexer("loc", self)
@property
def at(self) -> "_AtIndexer":
"""
Access a single value for a row/column label pair.
Similar to ``loc``, in that both provide label-based lookups. Use
``at`` if you only need to get or set a single value in a DataFrame
or Series.
Raises
------
KeyError
If 'label' does not exist in DataFrame.
See Also
--------
DataFrame.iat : Access a single value for a row/column pair by integer
position.
DataFrame.loc : Access a group of rows and columns by label(s).
Series.at : Access a single value using a label.
Examples
--------
>>> df = pd.DataFrame([[0, 2, 3], [0, 4, 1], [10, 20, 30]],
... index=[4, 5, 6], columns=['A', 'B', 'C'])
>>> df
A B C
4 0 2 3
5 0 4 1
6 10 20 30
Get value at specified row/column pair
>>> df.at[4, 'B']
2
Set value at specified row/column pair
>>> df.at[4, 'B'] = 10
>>> df.at[4, 'B']
10
Get value within a Series
>>> df.loc[5].at['B']
4
"""
return _AtIndexer("at", self)
@property
def iat(self) -> "_iAtIndexer":
"""
Access a single value for a row/column pair by integer position.
Similar to ``iloc``, in that both provide integer-based lookups. Use
``iat`` if you only need to get or set a single value in a DataFrame
or Series.
Raises
------
IndexError
When integer position is out of bounds.
See Also
--------
DataFrame.at : Access a single value for a row/column label pair.
DataFrame.loc : Access a group of rows and columns by label(s).
DataFrame.iloc : Access a group of rows and columns by integer position(s).
Examples
--------
>>> df = pd.DataFrame([[0, 2, 3], [0, 4, 1], [10, 20, 30]],
... columns=['A', 'B', 'C'])
>>> df
A B C
0 0 2 3
1 0 4 1
2 10 20 30
Get value at specified row/column pair
>>> df.iat[1, 2]
1
Set value at specified row/column pair
>>> df.iat[1, 2] = 10
>>> df.iat[1, 2]
10
Get value within a series
>>> df.loc[0].iat[1]
2
"""
return _iAtIndexer("iat", self)
class _LocationIndexer(_NDFrameIndexerBase):
_valid_types: str
axis = None
def __call__(self, axis=None):
# we need to return a copy of ourselves
new_self = type(self)(self.name, self.obj)
if axis is not None:
axis = self.obj._get_axis_number(axis)
new_self.axis = axis
return new_self
def _get_setitem_indexer(self, key):
"""
Convert a potentially-label-based key into a positional indexer.
"""
if self.name == "loc":
self._ensure_listlike_indexer(key)
if self.axis is not None:
return self._convert_tuple(key, is_setter=True)
ax = self.obj._get_axis(0)
if isinstance(ax, ABCMultiIndex) and self.name != "iloc":
try:
return ax.get_loc(key)
except (TypeError, KeyError, InvalidIndexError):
# TypeError e.g. passed a bool
pass
if isinstance(key, tuple):
try:
return self._convert_tuple(key, is_setter=True)
except IndexingError:
pass
if isinstance(key, range):
return list(key)
try:
return self._convert_to_indexer(key, axis=0, is_setter=True)
except TypeError as e:
# invalid indexer type vs 'other' indexing errors
if "cannot do" in str(e):
raise
elif "unhashable type" in str(e):
raise
raise IndexingError(key) from e
def _ensure_listlike_indexer(self, key, axis=None):
"""
Ensure that a list-like of column labels are all present by adding them if
they do not already exist.
Parameters
----------
key : list-like of column labels
Target labels.
axis : key axis if known
"""
column_axis = 1
# column only exists in 2-dimensional DataFrame
if self.ndim != 2:
return
if isinstance(key, tuple):
# key may be a tuple if we are .loc
# in that case, set key to the column part of key
key = key[column_axis]
axis = column_axis
if (
axis == column_axis
and not isinstance(self.obj.columns, ABCMultiIndex)
and is_list_like_indexer(key)
and not com.is_bool_indexer(key)
and all(is_hashable(k) for k in key)
):
for k in key:
if k not in self.obj:
self.obj[k] = np.nan
def __setitem__(self, key, value):
if isinstance(key, tuple):
key = tuple(com.apply_if_callable(x, self.obj) for x in key)
else:
key = com.apply_if_callable(key, self.obj)
indexer = self._get_setitem_indexer(key)
self._has_valid_setitem_indexer(key)
iloc = self if self.name == "iloc" else self.obj.iloc
iloc._setitem_with_indexer(indexer, value)
def _validate_key(self, key, axis: int):
"""
Ensure that key is valid for current indexer.
Parameters
----------
key : scalar, slice or list-like
Key requested.
axis : int
Dimension on which the indexing is being made.
Raises
------
TypeError
If the key (or some element of it) has wrong type.
IndexError
If the key (or some element of it) is out of bounds.
KeyError
If the key was not found.
"""
raise AbstractMethodError(self)
def _has_valid_tuple(self, key: Tuple):
"""
Check the key for valid keys across my indexer.
"""
for i, k in enumerate(key):
if i >= self.ndim:
raise IndexingError("Too many indexers")
try:
self._validate_key(k, i)
except ValueError as err:
raise ValueError(
"Location based indexing can only have "
f"[{self._valid_types}] types"
) from err
def _is_nested_tuple_indexer(self, tup: Tuple) -> bool:
"""
Returns
-------
bool
"""
if any(isinstance(ax, ABCMultiIndex) for ax in self.obj.axes):
return any(is_nested_tuple(tup, ax) for ax in self.obj.axes)
return False
def _convert_tuple(self, key, is_setter: bool = False):
keyidx = []
if self.axis is not None:
axis = self.obj._get_axis_number(self.axis)
for i in range(self.ndim):
if i == axis:
keyidx.append(
self._convert_to_indexer(key, axis=axis, is_setter=is_setter)
)
else:
keyidx.append(slice(None))
else:
for i, k in enumerate(key):
if i >= self.ndim:
raise IndexingError("Too many indexers")
idx = self._convert_to_indexer(k, axis=i, is_setter=is_setter)
keyidx.append(idx)
return tuple(keyidx)
def _getitem_tuple_same_dim(self, tup: Tuple):
"""
Index with indexers that should return an object of the same dimension
as self.obj.
This is only called after a failed call to _getitem_lowerdim.
"""
retval = self.obj
for i, key in enumerate(tup):
if com.is_null_slice(key):
continue
retval = getattr(retval, self.name)._getitem_axis(key, axis=i)
# We should never have retval.ndim < self.ndim, as that should
# be handled by the _getitem_lowerdim call above.
assert retval.ndim == self.ndim
return retval
def _getitem_lowerdim(self, tup: Tuple):
# we can directly get the axis result since the axis is specified
if self.axis is not None:
axis = self.obj._get_axis_number(self.axis)
return self._getitem_axis(tup, axis=axis)
# we may have a nested tuples indexer here
if self._is_nested_tuple_indexer(tup):
return self._getitem_nested_tuple(tup)
# we maybe be using a tuple to represent multiple dimensions here
ax0 = self.obj._get_axis(0)
# ...but iloc should handle the tuple as simple integer-location
# instead of checking it as multiindex representation (GH 13797)
if isinstance(ax0, ABCMultiIndex) and self.name != "iloc":
result = self._handle_lowerdim_multi_index_axis0(tup)
if result is not None:
return result
if len(tup) > self.ndim:
raise IndexingError("Too many indexers. handle elsewhere")
for i, key in enumerate(tup):
if is_label_like(key):
# We don't need to check for tuples here because those are
# caught by the _is_nested_tuple_indexer check above.
section = self._getitem_axis(key, axis=i)
# We should never have a scalar section here, because
# _getitem_lowerdim is only called after a check for
# is_scalar_access, which that would be.
if section.ndim == self.ndim:
# we're in the middle of slicing through a MultiIndex
# revise the key wrt to `section` by inserting an _NS
new_key = tup[:i] + (_NS,) + tup[i + 1 :]
else:
# Note: the section.ndim == self.ndim check above
# rules out having DataFrame here, so we dont need to worry
# about transposing.
new_key = tup[:i] + tup[i + 1 :]
if len(new_key) == 1:
new_key = new_key[0]
# Slices should return views, but calling iloc/loc with a null
# slice returns a new object.
if com.is_null_slice(new_key):
return section
# This is an elided recursive call to iloc/loc
return getattr(section, self.name)[new_key]
raise IndexingError("not applicable")
def _getitem_nested_tuple(self, tup: Tuple):
# we have a nested tuple so have at least 1 multi-index level
# we should be able to match up the dimensionality here
# we have too many indexers for our dim, but have at least 1
# multi-index dimension, try to see if we have something like
# a tuple passed to a series with a multi-index
if len(tup) > self.ndim:
if self.name != "loc":
# This should never be reached, but lets be explicit about it
raise ValueError("Too many indices")
result = self._handle_lowerdim_multi_index_axis0(tup)
if result is not None:
return result
# this is a series with a multi-index specified a tuple of
# selectors
axis = self.axis or 0
return self._getitem_axis(tup, axis=axis)
# handle the multi-axis by taking sections and reducing
# this is iterative
obj = self.obj
axis = 0
for key in tup:
if com.is_null_slice(key):
axis += 1
continue
current_ndim = obj.ndim
obj = getattr(obj, self.name)._getitem_axis(key, axis=axis)
axis += 1
# if we have a scalar, we are done
if is_scalar(obj) or not hasattr(obj, "ndim"):
break
# has the dim of the obj changed?
# GH 7199
if obj.ndim < current_ndim:
axis -= 1
return obj
def _convert_to_indexer(self, key, axis: int, is_setter: bool = False):
raise AbstractMethodError(self)
def __getitem__(self, key):
if type(key) is tuple:
key = tuple(com.apply_if_callable(x, self.obj) for x in key)
if self._is_scalar_access(key):
try:
return self.obj._get_value(*key, takeable=self._takeable)
except (KeyError, IndexError, AttributeError):
# AttributeError for IntervalTree get_value
pass
return self._getitem_tuple(key)
else:
# we by definition only have the 0th axis
axis = self.axis or 0
maybe_callable = com.apply_if_callable(key, self.obj)
return self._getitem_axis(maybe_callable, axis=axis)
def _is_scalar_access(self, key: Tuple):
raise NotImplementedError()
def _getitem_tuple(self, tup: Tuple):
raise AbstractMethodError(self)
def _getitem_axis(self, key, axis: int):
raise NotImplementedError()
def _has_valid_setitem_indexer(self, indexer) -> bool:
raise AbstractMethodError(self)
def _getbool_axis(self, key, axis: int):
# caller is responsible for ensuring non-None axis
labels = self.obj._get_axis(axis)
key = check_bool_indexer(labels, key)
inds = key.nonzero()[0]
return self.obj._take_with_is_copy(inds, axis=axis)
@doc(IndexingMixin.loc)
class _LocIndexer(_LocationIndexer):
_takeable: bool = False
_valid_types = (
"labels (MUST BE IN THE INDEX), slices of labels (BOTH "
"endpoints included! Can be slices of integers if the "
"index is integers), listlike of labels, boolean"
)
# -------------------------------------------------------------------
# Key Checks
@doc(_LocationIndexer._validate_key)
def _validate_key(self, key, axis: int):
# valid for a collection of labels (we check their presence later)
# slice of labels (where start-end in labels)
# slice of integers (only if in the labels)
# boolean
pass
def _has_valid_setitem_indexer(self, indexer) -> bool:
return True
def _is_scalar_access(self, key: Tuple) -> bool:
"""
Returns
-------
bool
"""
# this is a shortcut accessor to both .loc and .iloc
# that provide the equivalent access of .at and .iat
# a) avoid getting things via sections and (to minimize dtype changes)
# b) provide a performant path
if len(key) != self.ndim:
return False
for i, k in enumerate(key):
if not is_scalar(k):
return False
ax = self.obj.axes[i]
if isinstance(ax, ABCMultiIndex):
return False
if isinstance(k, str) and ax._supports_partial_string_indexing:
# partial string indexing, df.loc['2000', 'A']
# should not be considered scalar
return False
if not ax.is_unique:
return False
return True
# -------------------------------------------------------------------
# MultiIndex Handling
def _multi_take_opportunity(self, tup: Tuple) -> bool:
"""
Check whether there is the possibility to use ``_multi_take``.
Currently the limit is that all axes being indexed, must be indexed with
list-likes.
Parameters
----------
tup : tuple
Tuple of indexers, one per axis.
Returns
-------
bool
Whether the current indexing,
can be passed through `_multi_take`.
"""
if not all(is_list_like_indexer(x) for x in tup):
return False
# just too complicated
if any(com.is_bool_indexer(x) for x in tup):
return False
return True
def _multi_take(self, tup: Tuple):
"""
Create the indexers for the passed tuple of keys, and
executes the take operation. This allows the take operation to be
executed all at once, rather than once for each dimension.
Improving efficiency.
Parameters
----------
tup : tuple
Tuple of indexers, one per axis.
Returns
-------
values: same type as the object being indexed
"""
# GH 836
d = {
axis: self._get_listlike_indexer(key, axis)
for (key, axis) in zip(tup, self.obj._AXIS_ORDERS)
}
return self.obj._reindex_with_indexers(d, copy=True, allow_dups=True)
# -------------------------------------------------------------------
def _getitem_iterable(self, key, axis: int):
"""
Index current object with an an iterable collection of keys.
Parameters
----------
key : iterable
Targeted labels.
axis: int
Dimension on which the indexing is being made.
Raises
------
KeyError
If no key was found. Will change in the future to raise if not all
keys were found.
Returns
-------
scalar, DataFrame, or Series: indexed value(s).
"""
# we assume that not com.is_bool_indexer(key), as that is
# handled before we get here.
self._validate_key(key, axis)
# A collection of keys
keyarr, indexer = self._get_listlike_indexer(key, axis, raise_missing=False)
return self.obj._reindex_with_indexers(
{axis: [keyarr, indexer]}, copy=True, allow_dups=True
)
def _getitem_tuple(self, tup: Tuple):
try:
return self._getitem_lowerdim(tup)
except IndexingError:
pass
# no multi-index, so validate all of the indexers
self._has_valid_tuple(tup)
# ugly hack for GH #836
if self._multi_take_opportunity(tup):
return self._multi_take(tup)
return self._getitem_tuple_same_dim(tup)
def _get_label(self, label, axis: int):
# GH#5667 this will fail if the label is not present in the axis.
return self.obj.xs(label, axis=axis)
def _handle_lowerdim_multi_index_axis0(self, tup: Tuple):
# we have an axis0 multi-index, handle or raise
axis = self.axis or 0
try:
# fast path for series or for tup devoid of slices
return self._get_label(tup, axis=axis)
except TypeError:
# slices are unhashable
pass
except KeyError as ek:
# raise KeyError if number of indexers match
# else IndexingError will be raised
if len(tup) <= self.obj.index.nlevels and len(tup) > self.ndim:
raise ek
return None
def _getitem_axis(self, key, axis: int):
key = item_from_zerodim(key)
if is_iterator(key):
key = list(key)
labels = self.obj._get_axis(axis)
key = labels._get_partial_string_timestamp_match_key(key)
if isinstance(key, slice):
self._validate_key(key, axis)
return self._get_slice_axis(key, axis=axis)
elif com.is_bool_indexer(key):
return self._getbool_axis(key, axis=axis)
elif is_list_like_indexer(key):
# an iterable multi-selection
if not (isinstance(key, tuple) and isinstance(labels, ABCMultiIndex)):
if hasattr(key, "ndim") and key.ndim > 1:
raise ValueError("Cannot index with multidimensional key")
return self._getitem_iterable(key, axis=axis)
# nested tuple slicing
if is_nested_tuple(key, labels):
locs = labels.get_locs(key)
indexer = [slice(None)] * self.ndim
indexer[axis] = locs
return self.obj.iloc[tuple(indexer)]
# fall thru to straight lookup
self._validate_key(key, axis)
return self._get_label(key, axis=axis)
def _get_slice_axis(self, slice_obj: slice, axis: int):
"""
This is pretty simple as we just have to deal with labels.
"""
# caller is responsible for ensuring non-None axis
obj = self.obj
if not need_slice(slice_obj):
return obj.copy(deep=False)
labels = obj._get_axis(axis)
indexer = labels.slice_indexer(
slice_obj.start, slice_obj.stop, slice_obj.step, kind="loc"
)
if isinstance(indexer, slice):
return self.obj._slice(indexer, axis=axis)
else:
# DatetimeIndex overrides Index.slice_indexer and may
# return a DatetimeIndex instead of a slice object.
return self.obj.take(indexer, axis=axis)
def _convert_to_indexer(self, key, axis: int, is_setter: bool = False):
"""
Convert indexing key into something we can use to do actual fancy
indexing on a ndarray.
Examples
ix[:5] -> slice(0, 5)
ix[[1,2,3]] -> [1,2,3]
ix[['foo', 'bar', 'baz']] -> [i, j, k] (indices of foo, bar, baz)
Going by Zen of Python?
'In the face of ambiguity, refuse the temptation to guess.'
raise AmbiguousIndexError with integer labels?
- No, prefer label-based indexing
"""
labels = self.obj._get_axis(axis)
if isinstance(key, slice):
return labels._convert_slice_indexer(key, kind="loc")
# see if we are positional in nature
is_int_index = labels.is_integer()
is_int_positional = is_integer(key) and not is_int_index
if is_scalar(key) or isinstance(labels, ABCMultiIndex):
# Otherwise get_loc will raise InvalidIndexError
# if we are a label return me
try:
return labels.get_loc(key)
except LookupError:
if isinstance(key, tuple) and isinstance(labels, ABCMultiIndex):
if len(key) == labels.nlevels:
return {"key": key}
raise
except TypeError:
pass
except ValueError:
if not is_int_positional:
raise
# a positional
if is_int_positional:
# if we are setting and its not a valid location
# its an insert which fails by definition
# always valid
return {"key": key}
if is_nested_tuple(key, labels):
return labels.get_locs(key)
elif is_list_like_indexer(key):
if com.is_bool_indexer(key):
key = check_bool_indexer(labels, key)
(inds,) = key.nonzero()
return inds
else:
# When setting, missing keys are not allowed, even with .loc:
return self._get_listlike_indexer(key, axis, raise_missing=True)[1]
else:
try:
return labels.get_loc(key)
except LookupError:
# allow a not found key only if we are a setter
if not is_list_like_indexer(key):
return {"key": key}
raise
def _get_listlike_indexer(self, key, axis: int, raise_missing: bool = False):
"""
Transform a list-like of keys into a new index and an indexer.
Parameters
----------
key : list-like
Targeted labels.
axis: int
Dimension on which the indexing is being made.
raise_missing: bool, default False
Whether to raise a KeyError if some labels were not found.
Will be removed in the future, and then this method will always behave as
if ``raise_missing=True``.
Raises
------
KeyError
If at least one key was requested but none was found, and
raise_missing=True.
Returns
-------
keyarr: Index
New index (coinciding with 'key' if the axis is unique).
values : array-like
Indexer for the return object, -1 denotes keys not found.
"""
ax = self.obj._get_axis(axis)
# Have the index compute an indexer or return None
# if it cannot handle:
indexer, keyarr = ax._convert_listlike_indexer(key)
# We only act on all found values:
if indexer is not None and (indexer != -1).all():
self._validate_read_indexer(key, indexer, axis, raise_missing=raise_missing)
return ax[indexer], indexer
if ax.is_unique and not getattr(ax, "is_overlapping", False):
indexer = ax.get_indexer_for(key)
keyarr = ax.reindex(keyarr)[0]
else:
keyarr, indexer, new_indexer = ax._reindex_non_unique(keyarr)
self._validate_read_indexer(keyarr, indexer, axis, raise_missing=raise_missing)
return keyarr, indexer
def _validate_read_indexer(
self, key, indexer, axis: int, raise_missing: bool = False
):
"""
Check that indexer can be used to return a result.
e.g. at least one element was found,
unless the list of keys was actually empty.
Parameters
----------
key : list-like
Targeted labels (only used to show correct error message).
indexer: array-like of booleans
Indices corresponding to the key,
(with -1 indicating not found).
axis: int
Dimension on which the indexing is being made.
raise_missing: bool
Whether to raise a KeyError if some labels are not found. Will be
removed in the future, and then this method will always behave as
if raise_missing=True.
Raises
------
KeyError
If at least one key was requested but none was found, and
raise_missing=True.
"""
ax = self.obj._get_axis(axis)
if len(key) == 0:
return
# Count missing values:
missing = (indexer < 0).sum()
if missing:
if missing == len(indexer):
axis_name = self.obj._get_axis_name(axis)
raise KeyError(f"None of [{key}] are in the [{axis_name}]")
# We (temporarily) allow for some missing keys with .loc, except in
# some cases (e.g. setting) in which "raise_missing" will be False
if raise_missing:
not_found = list(set(key) - set(ax))
raise KeyError(f"{not_found} not in index")
# we skip the warning on Categorical
# as this check is actually done (check for
# non-missing values), but a bit later in the
# code, so we want to avoid warning & then
# just raising
if not ax.is_categorical():
raise KeyError(
"Passing list-likes to .loc or [] with any missing labels "
"is no longer supported, see "
"https://pandas.pydata.org/pandas-docs/stable/user_guide/indexing.html#deprecate-loc-reindex-listlike" # noqa:E501
)
@doc(IndexingMixin.iloc)
class _iLocIndexer(_LocationIndexer):
_valid_types = (
"integer, integer slice (START point is INCLUDED, END "
"point is EXCLUDED), listlike of integers, boolean array"
)
_takeable = True
# -------------------------------------------------------------------
# Key Checks
def _validate_key(self, key, axis: int):
if com.is_bool_indexer(key):
if hasattr(key, "index") and isinstance(key.index, Index):
if key.index.inferred_type == "integer":
raise NotImplementedError(
"iLocation based boolean "
"indexing on an integer type "
"is not available"
)
raise ValueError(
"iLocation based boolean indexing cannot use "
"an indexable as a mask"
)
return
if isinstance(key, slice):
return
elif is_integer(key):
self._validate_integer(key, axis)
elif isinstance(key, tuple):
# a tuple should already have been caught by this point
# so don't treat a tuple as a valid indexer
raise IndexingError("Too many indexers")
elif is_list_like_indexer(key):
arr = np.array(key)
len_axis = len(self.obj._get_axis(axis))
# check that the key has a numeric dtype
if not is_numeric_dtype(arr.dtype):
raise IndexError(f".iloc requires numeric indexers, got {arr}")
# check that the key does not exceed the maximum size of the index
if len(arr) and (arr.max() >= len_axis or arr.min() < -len_axis):
raise IndexError("positional indexers are out-of-bounds")
else:
raise ValueError(f"Can only index by location with a [{self._valid_types}]")
def _has_valid_setitem_indexer(self, indexer) -> bool:
"""
Validate that a positional indexer cannot enlarge its target
will raise if needed, does not modify the indexer externally.
Returns
-------
bool
"""
if isinstance(indexer, dict):
raise IndexError("iloc cannot enlarge its target object")
else:
if not isinstance(indexer, tuple):
indexer = _tuplify(self.ndim, indexer)
for ax, i in zip(self.obj.axes, indexer):
if isinstance(i, slice):
# should check the stop slice?
pass
elif is_list_like_indexer(i):
# should check the elements?
pass
elif is_integer(i):
if i >= len(ax):
raise IndexError("iloc cannot enlarge its target object")
elif isinstance(i, dict):
raise IndexError("iloc cannot enlarge its target object")
return True
def _is_scalar_access(self, key: Tuple) -> bool:
"""
Returns
-------
bool
"""
# this is a shortcut accessor to both .loc and .iloc
# that provide the equivalent access of .at and .iat
# a) avoid getting things via sections and (to minimize dtype changes)
# b) provide a performant path
if len(key) != self.ndim:
return False
for k in key:
if not is_integer(k):
return False
return True
def _validate_integer(self, key: int, axis: int) -> None:
"""
Check that 'key' is a valid position in the desired axis.
Parameters
----------
key : int
Requested position.
axis : int
Desired axis.
Raises
------
IndexError
If 'key' is not a valid position in axis 'axis'.
"""
len_axis = len(self.obj._get_axis(axis))
if key >= len_axis or key < -len_axis:
raise IndexError("single positional indexer is out-of-bounds")
# -------------------------------------------------------------------
def _getitem_tuple(self, tup: Tuple):
self._has_valid_tuple(tup)
try:
return self._getitem_lowerdim(tup)
except IndexingError:
pass
return self._getitem_tuple_same_dim(tup)
def _get_list_axis(self, key, axis: int):
"""
Return Series values by list or array of integers.
Parameters
----------
key : list-like positional indexer
axis : int
Returns
-------
Series object
Notes
-----
`axis` can only be zero.
"""
try:
return self.obj._take_with_is_copy(key, axis=axis)
except IndexError as err:
# re-raise with different error message
raise IndexError("positional indexers are out-of-bounds") from err
def _getitem_axis(self, key, axis: int):
if isinstance(key, slice):
return self._get_slice_axis(key, axis=axis)
if isinstance(key, list):
key = np.asarray(key)
if com.is_bool_indexer(key):
self._validate_key(key, axis)
return self._getbool_axis(key, axis=axis)
# a list of integers
elif is_list_like_indexer(key):
return self._get_list_axis(key, axis=axis)
# a single integer
else:
key = item_from_zerodim(key)
if not is_integer(key):
raise TypeError("Cannot index by location index with a non-integer key")
# validate the location
self._validate_integer(key, axis)
return self.obj._ixs(key, axis=axis)
def _get_slice_axis(self, slice_obj: slice, axis: int):
# caller is responsible for ensuring non-None axis
obj = self.obj
if not need_slice(slice_obj):
return obj.copy(deep=False)
labels = obj._get_axis(axis)
labels._validate_positional_slice(slice_obj)
return self.obj._slice(slice_obj, axis=axis)
def _convert_to_indexer(self, key, axis: int, is_setter: bool = False):
"""
Much simpler as we only have to deal with our valid types.
"""
return key
def _get_setitem_indexer(self, key):
# GH#32257 Fall through to let numnpy do validation
return key
# -------------------------------------------------------------------
def _setitem_with_indexer(self, indexer, value):
"""
_setitem_with_indexer is for setting values on a Series/DataFrame
using positional indexers.
If the relevant keys are not present, the Series/DataFrame may be
expanded.
This method is currently broken when dealing with non-unique Indexes,
since it goes from positional indexers back to labels when calling
BlockManager methods, see GH#12991, GH#22046, GH#15686.
"""
# also has the side effect of consolidating in-place
from pandas import Series
info_axis = self.obj._info_axis_number
# maybe partial set
take_split_path = self.obj._is_mixed_type
# if there is only one block/type, still have to take split path
# unless the block is one-dimensional or it can hold the value
if not take_split_path and self.obj._mgr.blocks:
(blk,) = self.obj._mgr.blocks
if 1 < blk.ndim: # in case of dict, keys are indices
val = list(value.values()) if isinstance(value, dict) else value
take_split_path = not blk._can_hold_element(val)
# if we have any multi-indexes that have non-trivial slices
# (not null slices) then we must take the split path, xref
# GH 10360, GH 27841
if isinstance(indexer, tuple) and len(indexer) == len(self.obj.axes):
for i, ax in zip(indexer, self.obj.axes):
if isinstance(ax, ABCMultiIndex) and not (
is_integer(i) or com.is_null_slice(i)
):
take_split_path = True
break
if isinstance(indexer, tuple):
nindexer = []
for i, idx in enumerate(indexer):
if isinstance(idx, dict):
# reindex the axis to the new value
# and set inplace
key, _ = convert_missing_indexer(idx)
# if this is the items axes, then take the main missing
# path first
# this correctly sets the dtype and avoids cache issues
# essentially this separates out the block that is needed
# to possibly be modified
if self.ndim > 1 and i == info_axis:
# add the new item, and set the value
# must have all defined axes if we have a scalar
# or a list-like on the non-info axes if we have a
# list-like
len_non_info_axes = (
len(_ax) for _i, _ax in enumerate(self.obj.axes) if _i != i
)
if any(not l for l in len_non_info_axes):
if not is_list_like_indexer(value):
raise ValueError(
"cannot set a frame with no "
"defined index and a scalar"
)
self.obj[key] = value
return
# add a new item with the dtype setup
self.obj[key] = _infer_fill_value(value)
new_indexer = convert_from_missing_indexer_tuple(
indexer, self.obj.axes
)
self._setitem_with_indexer(new_indexer, value)
return
# reindex the axis
# make sure to clear the cache because we are
# just replacing the block manager here
# so the object is the same
index = self.obj._get_axis(i)
labels = index.insert(len(index), key)
self.obj._mgr = self.obj.reindex(labels, axis=i)._mgr
self.obj._maybe_update_cacher(clear=True)
self.obj._is_copy = None
nindexer.append(labels.get_loc(key))
else:
nindexer.append(idx)
indexer = tuple(nindexer)
else:
indexer, missing = convert_missing_indexer(indexer)
if missing:
self._setitem_with_indexer_missing(indexer, value)
return
# set
item_labels = self.obj._get_axis(info_axis)
# align and set the values
if take_split_path:
# Above we only set take_split_path to True for 2D cases
assert self.ndim == 2
assert info_axis == 1
if not isinstance(indexer, tuple):
indexer = _tuplify(self.ndim, indexer)
if isinstance(value, ABCSeries):
value = self._align_series(indexer, value)
info_idx = indexer[info_axis]
if is_integer(info_idx):
info_idx = [info_idx]
labels = item_labels[info_idx]
# Ensure we have something we can iterate over
ilocs = info_idx
if isinstance(info_idx, slice):
ri = Index(range(len(self.obj.columns)))
ilocs = ri[info_idx]
plane_indexer = indexer[:1]
lplane_indexer = length_of_indexer(plane_indexer[0], self.obj.index)
# lplane_indexer gives the expected length of obj[indexer[0]]
if len(labels) == 1:
# We can operate on a single column
# require that we are setting the right number of values that
# we are indexing
if is_list_like_indexer(value) and 0 != lplane_indexer != len(value):
# Exclude zero-len for e.g. boolean masking that is all-false
raise ValueError(
"cannot set using a multi-index "
"selection indexer with a different "
"length than the value"
)
pi = plane_indexer[0] if lplane_indexer == 1 else plane_indexer
def isetter(loc, v):
# positional setting on column loc
ser = self.obj._ixs(loc, axis=1)
# perform the equivalent of a setitem on the info axis
# as we have a null slice or a slice with full bounds
# which means essentially reassign to the columns of a
# multi-dim object
# GH6149 (null slice), GH10408 (full bounds)
if isinstance(pi, tuple) and all(
com.is_null_slice(idx) or com.is_full_slice(idx, len(self.obj))
for idx in pi
):
ser = v
else:
# set the item, possibly having a dtype change
ser._consolidate_inplace()
ser = ser.copy()
ser._mgr = ser._mgr.setitem(indexer=pi, value=v)
ser._maybe_update_cacher(clear=True)
# reset the sliced object if unique
self.obj._iset_item(loc, ser)
# we need an iterable, with a ndim of at least 1
# eg. don't pass through np.array(0)
if is_list_like_indexer(value) and getattr(value, "ndim", 1) > 0:
# we have an equal len Frame
if isinstance(value, ABCDataFrame):
sub_indexer = list(indexer)
multiindex_indexer = isinstance(labels, ABCMultiIndex)
# TODO: we are implicitly assuming value.columns is unique
for loc in ilocs:
item = item_labels[loc]
if item in value:
sub_indexer[info_axis] = item
v = self._align_series(
tuple(sub_indexer), value[item], multiindex_indexer
)
else:
v = np.nan
isetter(loc, v)
# we have an equal len ndarray/convertible to our labels
# hasattr first, to avoid coercing to ndarray without reason.
# But we may be relying on the ndarray coercion to check ndim.
# Why not just convert to an ndarray earlier on if needed?
elif np.ndim(value) == 2:
# note that this coerces the dtype if we are mixed
# GH 7551
value = np.array(value, dtype=object)
if len(ilocs) != value.shape[1]:
raise ValueError(
"Must have equal len keys and value "
"when setting with an ndarray"
)
for i, loc in enumerate(ilocs):
# setting with a list, re-coerces
isetter(loc, value[:, i].tolist())
elif (
len(labels) == 1
and lplane_indexer == len(value)
and not is_scalar(plane_indexer[0])
):
# we have an equal len list/ndarray
# We only get here with len(labels) == len(ilocs) == 1
isetter(ilocs[0], value)
elif lplane_indexer == 0 and len(value) == len(self.obj.index):
# We get here in one case via .loc with a all-False mask
pass
else:
# per-label values
if len(ilocs) != len(value):
raise ValueError(
"Must have equal len keys and value "
"when setting with an iterable"
)
for loc, v in zip(ilocs, value):
isetter(loc, v)
else:
# scalar value
for loc in ilocs:
isetter(loc, value)
else:
if isinstance(indexer, tuple):
# if we are setting on the info axis ONLY
# set using those methods to avoid block-splitting
# logic here
if (
len(indexer) > info_axis
and is_integer(indexer[info_axis])
and all(
com.is_null_slice(idx)
for i, idx in enumerate(indexer)
if i != info_axis
)
and item_labels.is_unique
):
self.obj[item_labels[indexer[info_axis]]] = value
return
indexer = maybe_convert_ix(*indexer)
if isinstance(value, (ABCSeries, dict)):
# TODO(EA): ExtensionBlock.setitem this causes issues with
# setting for extensionarrays that store dicts. Need to decide
# if it's worth supporting that.
value = self._align_series(indexer, Series(value))
elif isinstance(value, ABCDataFrame):
value = self._align_frame(indexer, value)
# check for chained assignment
self.obj._check_is_chained_assignment_possible()
# actually do the set
self.obj._consolidate_inplace()
self.obj._mgr = self.obj._mgr.setitem(indexer=indexer, value=value)
self.obj._maybe_update_cacher(clear=True)
def _setitem_with_indexer_missing(self, indexer, value):
"""
Insert new row(s) or column(s) into the Series or DataFrame.
"""
from pandas import Series
# reindex the axis to the new value
# and set inplace
if self.ndim == 1:
index = self.obj.index
new_index = index.insert(len(index), indexer)
# we have a coerced indexer, e.g. a float
# that matches in an Int64Index, so
# we will not create a duplicate index, rather
# index to that element
# e.g. 0.0 -> 0
# GH#12246
if index.is_unique:
new_indexer = index.get_indexer([new_index[-1]])
if (new_indexer != -1).any():
return self._setitem_with_indexer(new_indexer, value)
# this preserves dtype of the value
new_values = Series([value])._values
if len(self.obj._values):
# GH#22717 handle casting compatibility that np.concatenate
# does incorrectly
new_values = concat_compat([self.obj._values, new_values])
self.obj._mgr = self.obj._constructor(
new_values, index=new_index, name=self.obj.name
)._mgr
self.obj._maybe_update_cacher(clear=True)
elif self.ndim == 2:
if not len(self.obj.columns):
# no columns and scalar
raise ValueError("cannot set a frame with no defined columns")
if isinstance(value, ABCSeries):
# append a Series
value = value.reindex(index=self.obj.columns, copy=True)
value.name = indexer
else:
# a list-list
if is_list_like_indexer(value):
# must have conforming columns
if len(value) != len(self.obj.columns):
raise ValueError("cannot set a row with mismatched columns")
value = Series(value, index=self.obj.columns, name=indexer)
self.obj._mgr = self.obj.append(value)._mgr
self.obj._maybe_update_cacher(clear=True)
def _align_series(self, indexer, ser: ABCSeries, multiindex_indexer: bool = False):
"""
Parameters
----------
indexer : tuple, slice, scalar
Indexer used to get the locations that will be set to `ser`.
ser : pd.Series
Values to assign to the locations specified by `indexer`.
multiindex_indexer : boolean, optional
Defaults to False. Should be set to True if `indexer` was from
a `pd.MultiIndex`, to avoid unnecessary broadcasting.
Returns
-------
`np.array` of `ser` broadcast to the appropriate shape for assignment
to the locations selected by `indexer`
"""
if isinstance(indexer, (slice, np.ndarray, list, Index)):
indexer = tuple([indexer])
if isinstance(indexer, tuple):
# flatten np.ndarray indexers
def ravel(i):
return i.ravel() if isinstance(i, np.ndarray) else i
indexer = tuple(map(ravel, indexer))
aligners = [not com.is_null_slice(idx) for idx in indexer]
sum_aligners = sum(aligners)
single_aligner = sum_aligners == 1
is_frame = self.ndim == 2
obj = self.obj
# are we a single alignable value on a non-primary
# dim (e.g. panel: 1,2, or frame: 0) ?
# hence need to align to a single axis dimension
# rather that find all valid dims
# frame
if is_frame:
single_aligner = single_aligner and aligners[0]
# we have a frame, with multiple indexers on both axes; and a
# series, so need to broadcast (see GH5206)
if sum_aligners == self.ndim and all(is_sequence(_) for _ in indexer):
ser = ser.reindex(obj.axes[0][indexer[0]], copy=True)._values
# single indexer
if len(indexer) > 1 and not multiindex_indexer:
len_indexer = len(indexer[1])
ser = np.tile(ser, len_indexer).reshape(len_indexer, -1).T
return ser
for i, idx in enumerate(indexer):
ax = obj.axes[i]
# multiple aligners (or null slices)
if is_sequence(idx) or isinstance(idx, slice):
if single_aligner and com.is_null_slice(idx):
continue
new_ix = ax[idx]
if not is_list_like_indexer(new_ix):
new_ix = Index([new_ix])
else:
new_ix = Index(new_ix)
if ser.index.equals(new_ix) or not len(new_ix):
return ser._values.copy()
return ser.reindex(new_ix)._values
# 2 dims
elif single_aligner:
# reindex along index
ax = self.obj.axes[1]
if ser.index.equals(ax) or not len(ax):
return ser._values.copy()
return ser.reindex(ax)._values
elif is_scalar(indexer):
ax = self.obj._get_axis(1)
if ser.index.equals(ax):
return ser._values.copy()
return ser.reindex(ax)._values
raise ValueError("Incompatible indexer with Series")
def _align_frame(self, indexer, df: ABCDataFrame):
is_frame = self.ndim == 2
if isinstance(indexer, tuple):
idx, cols = None, None
sindexers = []
for i, ix in enumerate(indexer):
ax = self.obj.axes[i]
if is_sequence(ix) or isinstance(ix, slice):
if isinstance(ix, np.ndarray):
ix = ix.ravel()
if idx is None:
idx = ax[ix]
elif cols is None:
cols = ax[ix]
else:
break
else:
sindexers.append(i)
if idx is not None and cols is not None:
if df.index.equals(idx) and df.columns.equals(cols):
val = df.copy()._values
else:
val = df.reindex(idx, columns=cols)._values
return val
elif (isinstance(indexer, slice) or is_list_like_indexer(indexer)) and is_frame:
ax = self.obj.index[indexer]
if df.index.equals(ax):
val = df.copy()._values
else:
# we have a multi-index and are trying to align
# with a particular, level GH3738
if (
isinstance(ax, ABCMultiIndex)
and isinstance(df.index, ABCMultiIndex)
and ax.nlevels != df.index.nlevels
):
raise TypeError(
"cannot align on a multi-index with out "
"specifying the join levels"
)
val = df.reindex(index=ax)._values
return val
raise ValueError("Incompatible indexer with DataFrame")
class _ScalarAccessIndexer(_NDFrameIndexerBase):
"""
Access scalars quickly.
"""
def _convert_key(self, key, is_setter: bool = False):
raise AbstractMethodError(self)
def __getitem__(self, key):
if not isinstance(key, tuple):
# we could have a convertible item here (e.g. Timestamp)
if not is_list_like_indexer(key):
key = tuple([key])
else:
raise ValueError("Invalid call for scalar access (getting)!")
key = self._convert_key(key)
return self.obj._get_value(*key, takeable=self._takeable)
def __setitem__(self, key, value):
if isinstance(key, tuple):
key = tuple(com.apply_if_callable(x, self.obj) for x in key)
else:
# scalar callable may return tuple
key = com.apply_if_callable(key, self.obj)
if not isinstance(key, tuple):
key = _tuplify(self.ndim, key)
if len(key) != self.ndim:
raise ValueError("Not enough indexers for scalar access (setting)!")
key = list(self._convert_key(key, is_setter=True))
self.obj._set_value(*key, value=value, takeable=self._takeable)
@doc(IndexingMixin.at)
class _AtIndexer(_ScalarAccessIndexer):
_takeable = False
def _convert_key(self, key, is_setter: bool = False):
"""
Require they keys to be the same type as the index. (so we don't
fallback)
"""
# allow arbitrary setting
if is_setter:
return list(key)
return key
@property
def _axes_are_unique(self) -> bool:
# Only relevant for self.ndim == 2
assert self.ndim == 2
return self.obj.index.is_unique and self.obj.columns.is_unique
def __getitem__(self, key):
if self.ndim == 2 and not self._axes_are_unique:
# GH#33041 fall back to .loc
if not isinstance(key, tuple) or not all(is_scalar(x) for x in key):
raise ValueError("Invalid call for scalar access (getting)!")
return self.obj.loc[key]
return super().__getitem__(key)
def __setitem__(self, key, value):
if self.ndim == 2 and not self._axes_are_unique:
# GH#33041 fall back to .loc
if not isinstance(key, tuple) or not all(is_scalar(x) for x in key):
raise ValueError("Invalid call for scalar access (setting)!")
self.obj.loc[key] = value
return
return super().__setitem__(key, value)
@doc(IndexingMixin.iat)
class _iAtIndexer(_ScalarAccessIndexer):
_takeable = True
def _convert_key(self, key, is_setter: bool = False):
"""
Require integer args. (and convert to label arguments)
"""
for a, i in zip(self.obj.axes, key):
if not is_integer(i):
raise ValueError("iAt based indexing can only have integer indexers")
return key
def _tuplify(ndim: int, loc: Hashable) -> Tuple[Union[Hashable, slice], ...]:
"""
Given an indexer for the first dimension, create an equivalent tuple
for indexing over all dimensions.
Parameters
----------
ndim : int
loc : object
Returns
-------
tuple
"""
_tup: List[Union[Hashable, slice]]
_tup = [slice(None, None) for _ in range(ndim)]
_tup[0] = loc
return tuple(_tup)
def convert_to_index_sliceable(obj: "DataFrame", key):
"""
If we are index sliceable, then return my slicer, otherwise return None.
"""
idx = obj.index
if isinstance(key, slice):
return idx._convert_slice_indexer(key, kind="getitem")
elif isinstance(key, str):
# we are an actual column
if key in obj.columns:
return None
# We might have a datetimelike string that we can translate to a
# slice here via partial string indexing
if idx._supports_partial_string_indexing:
try:
return idx._get_string_slice(key)
except (KeyError, ValueError, NotImplementedError):
return None
return None
def check_bool_indexer(index: Index, key) -> np.ndarray:
"""
Check if key is a valid boolean indexer for an object with such index and
perform reindexing or conversion if needed.
This function assumes that is_bool_indexer(key) == True.
Parameters
----------
index : Index
Index of the object on which the indexing is done.
key : list-like
Boolean indexer to check.
Returns
-------
np.array
Resulting key.
Raises
------
IndexError
If the key does not have the same length as index.
IndexingError
If the index of the key is unalignable to index.
"""
result = key
if isinstance(key, ABCSeries) and not key.index.equals(index):
result = result.reindex(index)
mask = isna(result._values)
if mask.any():
raise IndexingError(
"Unalignable boolean Series provided as "
"indexer (index of the boolean Series and of "
"the indexed object do not match)."
)
result = result.astype(bool)._values
elif is_object_dtype(key):
# key might be object-dtype bool, check_array_indexer needs bool array
result = np.asarray(result, dtype=bool)
result = check_array_indexer(index, result)
else:
result = check_array_indexer(index, result)
return result
def convert_missing_indexer(indexer):
"""
Reverse convert a missing indexer, which is a dict
return the scalar indexer and a boolean indicating if we converted
"""
if isinstance(indexer, dict):
# a missing key (but not a tuple indexer)
indexer = indexer["key"]
if isinstance(indexer, bool):
raise KeyError("cannot use a single bool to index into setitem")
return indexer, True
return indexer, False
def convert_from_missing_indexer_tuple(indexer, axes):
"""
Create a filtered indexer that doesn't have any missing indexers.
"""
def get_indexer(_i, _idx):
return axes[_i].get_loc(_idx["key"]) if isinstance(_idx, dict) else _idx
return tuple(get_indexer(_i, _idx) for _i, _idx in enumerate(indexer))
def maybe_convert_ix(*args):
"""
We likely want to take the cross-product.
"""
ixify = True
for arg in args:
if not isinstance(arg, (np.ndarray, list, ABCSeries, Index)):
ixify = False
if ixify:
return np.ix_(*args)
else:
return args
def is_nested_tuple(tup, labels) -> bool:
"""
Returns
-------
bool
"""
# check for a compatible nested tuple and multiindexes among the axes
if not isinstance(tup, tuple):
return False
for k in tup:
if is_list_like(k) or isinstance(k, slice):
return isinstance(labels, ABCMultiIndex)
return False
def is_label_like(key) -> bool:
"""
Returns
-------
bool
"""
# select a label or row
return not isinstance(key, slice) and not is_list_like_indexer(key)
def need_slice(obj) -> bool:
"""
Returns
-------
bool
"""
return (
obj.start is not None
or obj.stop is not None
or (obj.step is not None and obj.step != 1)
)
def _non_reducing_slice(slice_):
"""
Ensurse that a slice doesn't reduce to a Series or Scalar.
Any user-paseed `subset` should have this called on it
to make sure we're always working with DataFrames.
"""
# default to column slice, like DataFrame
# ['A', 'B'] -> IndexSlices[:, ['A', 'B']]
kinds = (ABCSeries, np.ndarray, Index, list, str)
if isinstance(slice_, kinds):
slice_ = IndexSlice[:, slice_]
def pred(part) -> bool:
"""
Returns
-------
bool
True if slice does *not* reduce,
False if `part` is a tuple.
"""
# true when slice does *not* reduce, False when part is a tuple,
# i.e. MultiIndex slice
return (isinstance(part, slice) or is_list_like(part)) and not isinstance(
part, tuple
)
if not is_list_like(slice_):
if not isinstance(slice_, slice):
# a 1-d slice, like df.loc[1]
slice_ = [[slice_]]
else:
# slice(a, b, c)
slice_ = [slice_] # to tuplize later
else:
slice_ = [part if pred(part) else [part] for part in slice_]
return tuple(slice_)
def _maybe_numeric_slice(df, slice_, include_bool=False):
"""
Want nice defaults for background_gradient that don't break
with non-numeric data. But if slice_ is passed go with that.
"""
if slice_ is None:
dtypes = [np.number]
if include_bool:
dtypes.append(bool)
slice_ = IndexSlice[:, df.select_dtypes(include=dtypes).columns]
return slice_
| BugsInPy/BugsInPy/temp/projects/pandas/bug-19-fixed/pandas/pandas/core/indexing.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-19-buggy/pandas/pandas/core/indexing.py |
pandas-bug-152 | """
Data structure for 1-dimensional cross-sectional and time series data
"""
from collections import OrderedDict
from io import StringIO
from shutil import get_terminal_size
from textwrap import dedent
from typing import Any, Callable
import warnings
import numpy as np
from pandas._config import get_option
from pandas._libs import index as libindex, lib, reshape, tslibs
from pandas.compat import PY36
from pandas.compat.numpy import function as nv
from pandas.util._decorators import Appender, Substitution, deprecate
from pandas.util._validators import validate_bool_kwarg
from pandas.core.dtypes.common import (
_is_unorderable_exception,
ensure_platform_int,
is_bool,
is_categorical,
is_categorical_dtype,
is_datetime64_dtype,
is_datetimelike,
is_dict_like,
is_extension_array_dtype,
is_extension_type,
is_hashable,
is_integer,
is_iterator,
is_list_like,
is_object_dtype,
is_scalar,
is_string_like,
is_timedelta64_dtype,
)
from pandas.core.dtypes.generic import (
ABCDataFrame,
ABCDatetimeArray,
ABCDatetimeIndex,
ABCSeries,
ABCSparseArray,
ABCSparseSeries,
)
from pandas.core.dtypes.missing import (
isna,
na_value_for_dtype,
notna,
remove_na_arraylike,
)
import pandas as pd
from pandas.core import algorithms, base, generic, nanops, ops
from pandas.core.accessor import CachedAccessor
from pandas.core.arrays import ExtensionArray, SparseArray
from pandas.core.arrays.categorical import Categorical, CategoricalAccessor
from pandas.core.arrays.sparse import SparseAccessor
import pandas.core.common as com
from pandas.core.construction import extract_array, sanitize_array
from pandas.core.index import (
Float64Index,
Index,
InvalidIndexError,
MultiIndex,
ensure_index,
)
from pandas.core.indexers import maybe_convert_indices
from pandas.core.indexes.accessors import CombinedDatetimelikeProperties
import pandas.core.indexes.base as ibase
from pandas.core.indexes.datetimes import DatetimeIndex
from pandas.core.indexes.period import PeriodIndex
from pandas.core.indexes.timedeltas import TimedeltaIndex
from pandas.core.indexing import check_bool_indexer
from pandas.core.internals import SingleBlockManager
from pandas.core.strings import StringMethods
from pandas.core.tools.datetimes import to_datetime
import pandas.io.formats.format as fmt
import pandas.plotting
__all__ = ["Series"]
_shared_doc_kwargs = dict(
axes="index",
klass="Series",
axes_single_arg="{0 or 'index'}",
axis="""axis : {0 or 'index'}
Parameter needed for compatibility with DataFrame.""",
inplace="""inplace : boolean, default False
If True, performs operation inplace and returns None.""",
unique="np.ndarray",
duplicated="Series",
optional_by="",
optional_mapper="",
optional_labels="",
optional_axis="",
versionadded_to_excel="\n .. versionadded:: 0.20.0\n",
)
# see gh-16971
def remove_na(arr):
"""
Remove null values from array like structure.
.. deprecated:: 0.21.0
Use s[s.notnull()] instead.
"""
warnings.warn(
"remove_na is deprecated and is a private function. Do not use.",
FutureWarning,
stacklevel=2,
)
return remove_na_arraylike(arr)
def _coerce_method(converter):
"""
Install the scalar coercion methods.
"""
def wrapper(self):
if len(self) == 1:
return converter(self.iloc[0])
raise TypeError("cannot convert the series to {0}".format(str(converter)))
wrapper.__name__ = "__{name}__".format(name=converter.__name__)
return wrapper
# ----------------------------------------------------------------------
# Series class
class Series(base.IndexOpsMixin, generic.NDFrame):
"""
One-dimensional ndarray with axis labels (including time series).
Labels need not be unique but must be a hashable type. The object
supports both integer- and label-based indexing and provides a host of
methods for performing operations involving the index. Statistical
methods from ndarray have been overridden to automatically exclude
missing data (currently represented as NaN).
Operations between Series (+, -, /, *, **) align values based on their
associated index values-- they need not be the same length. The result
index will be the sorted union of the two indexes.
Parameters
----------
data : array-like, Iterable, dict, or scalar value
Contains data stored in Series.
.. versionchanged:: 0.23.0
If data is a dict, argument order is maintained for Python 3.6
and later.
index : array-like or Index (1d)
Values must be hashable and have the same length as `data`.
Non-unique index values are allowed. Will default to
RangeIndex (0, 1, 2, ..., n) if not provided. If both a dict and index
sequence are used, the index will override the keys found in the
dict.
dtype : str, numpy.dtype, or ExtensionDtype, optional
Data type for the output Series. If not specified, this will be
inferred from `data`.
See the :ref:`user guide <basics.dtypes>` for more usages.
copy : bool, default False
Copy input data.
"""
_metadata = ["name"]
_accessors = {"dt", "cat", "str", "sparse"}
# tolist is not actually deprecated, just suppressed in the __dir__
_deprecations = generic.NDFrame._deprecations | frozenset(
["asobject", "reshape", "valid", "tolist"]
)
# Override cache_readonly bc Series is mutable
hasnans = property(
base.IndexOpsMixin.hasnans.func, doc=base.IndexOpsMixin.hasnans.__doc__
)
_data = None # type: SingleBlockManager
# ----------------------------------------------------------------------
# Constructors
def __init__(
self, data=None, index=None, dtype=None, name=None, copy=False, fastpath=False
):
# we are called internally, so short-circuit
if fastpath:
# data is an ndarray, index is defined
if not isinstance(data, SingleBlockManager):
data = SingleBlockManager(data, index, fastpath=True)
if copy:
data = data.copy()
if index is None:
index = data.index
else:
if index is not None:
index = ensure_index(index)
if data is None:
data = {}
if dtype is not None:
# GH 26336: explicitly handle 'category' to avoid warning
# TODO: Remove after CategoricalDtype defaults to ordered=False
if (
isinstance(dtype, str)
and dtype == "category"
and is_categorical(data)
):
dtype = data.dtype
dtype = self._validate_dtype(dtype)
if isinstance(data, MultiIndex):
raise NotImplementedError(
"initializing a Series from a MultiIndex is not supported"
)
elif isinstance(data, Index):
if name is None:
name = data.name
if dtype is not None:
# astype copies
data = data.astype(dtype)
else:
# need to copy to avoid aliasing issues
data = data._values.copy()
if isinstance(data, ABCDatetimeIndex) and data.tz is not None:
# GH#24096 need copy to be deep for datetime64tz case
# TODO: See if we can avoid these copies
data = data._values.copy(deep=True)
copy = False
elif isinstance(data, np.ndarray):
pass
elif isinstance(data, (ABCSeries, ABCSparseSeries)):
if name is None:
name = data.name
if index is None:
index = data.index
else:
data = data.reindex(index, copy=copy)
data = data._data
elif isinstance(data, dict):
data, index = self._init_dict(data, index, dtype)
dtype = None
copy = False
elif isinstance(data, SingleBlockManager):
if index is None:
index = data.index
elif not data.index.equals(index) or copy:
# GH#19275 SingleBlockManager input should only be called
# internally
raise AssertionError(
"Cannot pass both SingleBlockManager "
"`data` argument and a different "
"`index` argument. `copy` must "
"be False."
)
elif is_extension_array_dtype(data):
pass
elif isinstance(data, (set, frozenset)):
raise TypeError(
"{0!r} type is unordered".format(data.__class__.__name__)
)
elif isinstance(data, ABCSparseArray):
# handle sparse passed here (and force conversion)
data = data.to_dense()
else:
data = com.maybe_iterable_to_list(data)
if index is None:
if not is_list_like(data):
data = [data]
index = ibase.default_index(len(data))
elif is_list_like(data):
# a scalar numpy array is list-like but doesn't
# have a proper length
try:
if len(index) != len(data):
raise ValueError(
"Length of passed values is {val}, "
"index implies {ind}".format(val=len(data), ind=len(index))
)
except TypeError:
pass
# create/copy the manager
if isinstance(data, SingleBlockManager):
if dtype is not None:
data = data.astype(dtype=dtype, errors="ignore", copy=copy)
elif copy:
data = data.copy()
else:
data = sanitize_array(data, index, dtype, copy, raise_cast_failure=True)
data = SingleBlockManager(data, index, fastpath=True)
generic.NDFrame.__init__(self, data, fastpath=True)
self.name = name
self._set_axis(0, index, fastpath=True)
def _init_dict(self, data, index=None, dtype=None):
"""
Derive the "_data" and "index" attributes of a new Series from a
dictionary input.
Parameters
----------
data : dict or dict-like
Data used to populate the new Series
index : Index or index-like, default None
index for the new Series: if None, use dict keys
dtype : dtype, default None
dtype for the new Series: if None, infer from data
Returns
-------
_data : BlockManager for the new Series
index : index for the new Series
"""
# Looking for NaN in dict doesn't work ({np.nan : 1}[float('nan')]
# raises KeyError), so we iterate the entire dict, and align
if data:
keys, values = zip(*data.items())
values = list(values)
elif index is not None:
# fastpath for Series(data=None). Just use broadcasting a scalar
# instead of reindexing.
values = na_value_for_dtype(dtype)
keys = index
else:
keys, values = [], []
# Input is now list-like, so rely on "standard" construction:
s = Series(values, index=keys, dtype=dtype)
# Now we just make sure the order is respected, if any
if data and index is not None:
s = s.reindex(index, copy=False)
elif not PY36 and not isinstance(data, OrderedDict) and data:
# Need the `and data` to avoid sorting Series(None, index=[...])
# since that isn't really dict-like
try:
s = s.sort_index()
except TypeError:
pass
return s._data, s.index
@classmethod
def from_array(
cls, arr, index=None, name=None, dtype=None, copy=False, fastpath=False
):
"""
Construct Series from array.
.. deprecated:: 0.23.0
Use pd.Series(..) constructor instead.
Returns
-------
Series
Constructed Series.
"""
warnings.warn(
"'from_array' is deprecated and will be removed in a "
"future version. Please use the pd.Series(..) "
"constructor instead.",
FutureWarning,
stacklevel=2,
)
if isinstance(arr, ABCSparseArray):
from pandas.core.sparse.series import SparseSeries
cls = SparseSeries
return cls(
arr, index=index, name=name, dtype=dtype, copy=copy, fastpath=fastpath
)
# ----------------------------------------------------------------------
@property
def _constructor(self):
return Series
@property
def _constructor_expanddim(self):
from pandas.core.frame import DataFrame
return DataFrame
# types
@property
def _can_hold_na(self):
return self._data._can_hold_na
_index = None
def _set_axis(self, axis, labels, fastpath=False):
"""
Override generic, we want to set the _typ here.
"""
if not fastpath:
labels = ensure_index(labels)
is_all_dates = labels.is_all_dates
if is_all_dates:
if not isinstance(labels, (DatetimeIndex, PeriodIndex, TimedeltaIndex)):
try:
labels = DatetimeIndex(labels)
# need to set here because we changed the index
if fastpath:
self._data.set_axis(axis, labels)
except (tslibs.OutOfBoundsDatetime, ValueError):
# labels may exceeds datetime bounds,
# or not be a DatetimeIndex
pass
self._set_subtyp(is_all_dates)
object.__setattr__(self, "_index", labels)
if not fastpath:
self._data.set_axis(axis, labels)
def _set_subtyp(self, is_all_dates):
if is_all_dates:
object.__setattr__(self, "_subtyp", "time_series")
else:
object.__setattr__(self, "_subtyp", "series")
def _update_inplace(self, result, **kwargs):
# we want to call the generic version and not the IndexOpsMixin
return generic.NDFrame._update_inplace(self, result, **kwargs)
@property
def name(self):
"""
Return name of the Series.
"""
return self._name
@name.setter
def name(self, value):
if value is not None and not is_hashable(value):
raise TypeError("Series.name must be a hashable type")
object.__setattr__(self, "_name", value)
# ndarray compatibility
@property
def dtype(self):
"""
Return the dtype object of the underlying data.
"""
return self._data.dtype
@property
def dtypes(self):
"""
Return the dtype object of the underlying data.
"""
return self._data.dtype
@property
def ftype(self):
"""
Return if the data is sparse|dense.
.. deprecated:: 0.25.0
Use :func:`dtype` instead.
"""
warnings.warn(
"Series.ftype is deprecated and will "
"be removed in a future version. "
"Use Series.dtype instead.",
FutureWarning,
stacklevel=2,
)
return self._data.ftype
@property
def ftypes(self):
"""
Return if the data is sparse|dense.
.. deprecated:: 0.25.0
Use :func:`dtypes` instead.
"""
warnings.warn(
"Series.ftypes is deprecated and will "
"be removed in a future version. "
"Use Series.dtype instead.",
FutureWarning,
stacklevel=2,
)
return self._data.ftype
@property
def values(self):
"""
Return Series as ndarray or ndarray-like depending on the dtype.
.. warning::
We recommend using :attr:`Series.array` or
:meth:`Series.to_numpy`, depending on whether you need
a reference to the underlying data or a NumPy array.
Returns
-------
numpy.ndarray or ndarray-like
See Also
--------
Series.array : Reference to the underlying data.
Series.to_numpy : A NumPy array representing the underlying data.
Examples
--------
>>> pd.Series([1, 2, 3]).values
array([1, 2, 3])
>>> pd.Series(list('aabc')).values
array(['a', 'a', 'b', 'c'], dtype=object)
>>> pd.Series(list('aabc')).astype('category').values
[a, a, b, c]
Categories (3, object): [a, b, c]
Timezone aware datetime data is converted to UTC:
>>> pd.Series(pd.date_range('20130101', periods=3,
... tz='US/Eastern')).values
array(['2013-01-01T05:00:00.000000000',
'2013-01-02T05:00:00.000000000',
'2013-01-03T05:00:00.000000000'], dtype='datetime64[ns]')
"""
return self._data.external_values()
@property
def _values(self):
"""
Return the internal repr of this data.
"""
return self._data.internal_values()
def get_values(self):
"""
Same as values (but handles sparseness conversions); is a view.
.. deprecated:: 0.25.0
Use :meth:`Series.to_numpy` or :attr:`Series.array` instead.
Returns
-------
numpy.ndarray
Data of the Series.
"""
warnings.warn(
"The 'get_values' method is deprecated and will be removed in a "
"future version. Use '.to_numpy()' or '.array' instead.",
FutureWarning,
stacklevel=2,
)
return self._internal_get_values()
def _internal_get_values(self):
return self._data.get_values()
@property
def asobject(self):
"""
Return object Series which contains boxed values.
.. deprecated:: 0.23.0
Use ``astype(object)`` instead.
*this is an internal non-public method*
"""
warnings.warn(
"'asobject' is deprecated. Use 'astype(object)' instead",
FutureWarning,
stacklevel=2,
)
return self.astype(object).values
# ops
def ravel(self, order="C"):
"""
Return the flattened underlying data as an ndarray.
Returns
-------
numpy.ndarray or ndarray-like
Flattened data of the Series.
See Also
--------
numpy.ndarray.ravel
"""
return self._values.ravel(order=order)
def compress(self, condition, *args, **kwargs):
"""
Return selected slices of an array along given axis as a Series.
.. deprecated:: 0.24.0
Returns
-------
Series
Series without the slices for which condition is false.
See Also
--------
numpy.ndarray.compress
"""
msg = (
"Series.compress(condition) is deprecated. "
"Use 'Series[condition]' or "
"'np.asarray(series).compress(condition)' instead."
)
warnings.warn(msg, FutureWarning, stacklevel=2)
nv.validate_compress(args, kwargs)
return self[condition]
def nonzero(self):
"""
Return the *integer* indices of the elements that are non-zero.
.. deprecated:: 0.24.0
Please use .to_numpy().nonzero() as a replacement.
This method is equivalent to calling `numpy.nonzero` on the
series data. For compatibility with NumPy, the return value is
the same (a tuple with an array of indices for each dimension),
but it will always be a one-item tuple because series only have
one dimension.
Returns
-------
numpy.ndarray
Indices of elements that are non-zero.
See Also
--------
numpy.nonzero
Examples
--------
>>> s = pd.Series([0, 3, 0, 4])
>>> s.nonzero()
(array([1, 3]),)
>>> s.iloc[s.nonzero()[0]]
1 3
3 4
dtype: int64
# same return although index of s is different
>>> s = pd.Series([0, 3, 0, 4], index=['a', 'b', 'c', 'd'])
>>> s.nonzero()
(array([1, 3]),)
>>> s.iloc[s.nonzero()[0]]
b 3
d 4
dtype: int64
"""
msg = (
"Series.nonzero() is deprecated "
"and will be removed in a future version."
"Use Series.to_numpy().nonzero() instead"
)
warnings.warn(msg, FutureWarning, stacklevel=2)
return self._values.nonzero()
def put(self, *args, **kwargs):
"""
Apply the `put` method to its `values` attribute if it has one.
.. deprecated:: 0.25.0
See Also
--------
numpy.ndarray.put
"""
warnings.warn(
"`put` has been deprecated and will be removed in a future version.",
FutureWarning,
stacklevel=2,
)
self._values.put(*args, **kwargs)
def __len__(self):
"""
Return the length of the Series.
"""
return len(self._data)
def view(self, dtype=None):
"""
Create a new view of the Series.
This function will return a new Series with a view of the same
underlying values in memory, optionally reinterpreted with a new data
type. The new data type must preserve the same size in bytes as to not
cause index misalignment.
Parameters
----------
dtype : data type
Data type object or one of their string representations.
Returns
-------
Series
A new Series object as a view of the same data in memory.
See Also
--------
numpy.ndarray.view : Equivalent numpy function to create a new view of
the same data in memory.
Notes
-----
Series are instantiated with ``dtype=float64`` by default. While
``numpy.ndarray.view()`` will return a view with the same data type as
the original array, ``Series.view()`` (without specified dtype)
will try using ``float64`` and may fail if the original data type size
in bytes is not the same.
Examples
--------
>>> s = pd.Series([-2, -1, 0, 1, 2], dtype='int8')
>>> s
0 -2
1 -1
2 0
3 1
4 2
dtype: int8
The 8 bit signed integer representation of `-1` is `0b11111111`, but
the same bytes represent 255 if read as an 8 bit unsigned integer:
>>> us = s.view('uint8')
>>> us
0 254
1 255
2 0
3 1
4 2
dtype: uint8
The views share the same underlying values:
>>> us[0] = 128
>>> s
0 -128
1 -1
2 0
3 1
4 2
dtype: int8
"""
return self._constructor(
self._values.view(dtype), index=self.index
).__finalize__(self)
# ----------------------------------------------------------------------
# NDArray Compat
_HANDLED_TYPES = (Index, ExtensionArray, np.ndarray)
def __array_ufunc__(
self, ufunc: Callable, method: str, *inputs: Any, **kwargs: Any
):
# TODO: handle DataFrame
cls = type(self)
# for binary ops, use our custom dunder methods
result = ops.maybe_dispatch_ufunc_to_dunder_op(
self, ufunc, method, *inputs, **kwargs
)
if result is not NotImplemented:
return result
# Determine if we should defer.
no_defer = (np.ndarray.__array_ufunc__, cls.__array_ufunc__)
for item in inputs:
higher_priority = (
hasattr(item, "__array_priority__")
and item.__array_priority__ > self.__array_priority__
)
has_array_ufunc = (
hasattr(item, "__array_ufunc__")
and type(item).__array_ufunc__ not in no_defer
and not isinstance(item, self._HANDLED_TYPES)
)
if higher_priority or has_array_ufunc:
return NotImplemented
# align all the inputs.
names = [getattr(x, "name") for x in inputs if hasattr(x, "name")]
types = tuple(type(x) for x in inputs)
# TODO: dataframe
alignable = [x for x, t in zip(inputs, types) if issubclass(t, Series)]
if len(alignable) > 1:
# This triggers alignment.
# At the moment, there aren't any ufuncs with more than two inputs
# so this ends up just being x1.index | x2.index, but we write
# it to handle *args.
index = alignable[0].index
for s in alignable[1:]:
index |= s.index
inputs = tuple(
x.reindex(index) if issubclass(t, Series) else x
for x, t in zip(inputs, types)
)
else:
index = self.index
inputs = tuple(extract_array(x, extract_numpy=True) for x in inputs)
result = getattr(ufunc, method)(*inputs, **kwargs)
if len(set(names)) == 1:
# we require names to be hashable, right?
name = names[0] # type: Any
else:
name = None
def construct_return(result):
if lib.is_scalar(result):
return result
elif result.ndim > 1:
# e.g. np.subtract.outer
if method == "outer":
msg = (
"outer method for ufunc {} is not implemented on "
"pandas objects. Returning an ndarray, but in the "
"future this will raise a 'NotImplementedError'. "
"Consider explicitly converting the Series "
"to an array with '.array' first."
)
warnings.warn(msg.format(ufunc), FutureWarning, stacklevel=3)
return result
return self._constructor(result, index=index, name=name, copy=False)
if type(result) is tuple:
# multiple return values
return tuple(construct_return(x) for x in result)
elif method == "at":
# no return value
return None
else:
return construct_return(result)
def __array__(self, dtype=None):
"""
Return the values as a NumPy array.
Users should not call this directly. Rather, it is invoked by
:func:`numpy.array` and :func:`numpy.asarray`.
Parameters
----------
dtype : str or numpy.dtype, optional
The dtype to use for the resulting NumPy array. By default,
the dtype is inferred from the data.
Returns
-------
numpy.ndarray
The values in the series converted to a :class:`numpy.ndarary`
with the specified `dtype`.
See Also
--------
array : Create a new array from data.
Series.array : Zero-copy view to the array backing the Series.
Series.to_numpy : Series method for similar behavior.
Examples
--------
>>> ser = pd.Series([1, 2, 3])
>>> np.asarray(ser)
array([1, 2, 3])
For timezone-aware data, the timezones may be retained with
``dtype='object'``
>>> tzser = pd.Series(pd.date_range('2000', periods=2, tz="CET"))
>>> np.asarray(tzser, dtype="object")
array([Timestamp('2000-01-01 00:00:00+0100', tz='CET', freq='D'),
Timestamp('2000-01-02 00:00:00+0100', tz='CET', freq='D')],
dtype=object)
Or the values may be localized to UTC and the tzinfo discared with
``dtype='datetime64[ns]'``
>>> np.asarray(tzser, dtype="datetime64[ns]") # doctest: +ELLIPSIS
array(['1999-12-31T23:00:00.000000000', ...],
dtype='datetime64[ns]')
"""
if (
dtype is None
and isinstance(self.array, ABCDatetimeArray)
and getattr(self.dtype, "tz", None)
):
msg = (
"Converting timezone-aware DatetimeArray to timezone-naive "
"ndarray with 'datetime64[ns]' dtype. In the future, this "
"will return an ndarray with 'object' dtype where each "
"element is a 'pandas.Timestamp' with the correct 'tz'.\n\t"
"To accept the future behavior, pass 'dtype=object'.\n\t"
"To keep the old behavior, pass 'dtype=\"datetime64[ns]\"'."
)
warnings.warn(msg, FutureWarning, stacklevel=3)
dtype = "M8[ns]"
return np.asarray(self.array, dtype)
# ----------------------------------------------------------------------
# Unary Methods
@property
def real(self):
"""
Return the real value of vector.
.. deprecated:: 0.25.0
"""
warnings.warn(
"`real` is deprecated and will be removed in a future version. "
"To eliminate this warning for a Series `ser`, use "
"`np.real(ser.to_numpy())` or `ser.to_numpy().real`.",
FutureWarning,
stacklevel=2,
)
return self.values.real
@real.setter
def real(self, v):
self.values.real = v
@property
def imag(self):
"""
Return imag value of vector.
.. deprecated:: 0.25.0
"""
warnings.warn(
"`imag` is deprecated and will be removed in a future version. "
"To eliminate this warning for a Series `ser`, use "
"`np.imag(ser.to_numpy())` or `ser.to_numpy().imag`.",
FutureWarning,
stacklevel=2,
)
return self.values.imag
@imag.setter
def imag(self, v):
self.values.imag = v
# coercion
__float__ = _coerce_method(float)
__long__ = _coerce_method(int)
__int__ = _coerce_method(int)
# ----------------------------------------------------------------------
def _unpickle_series_compat(self, state):
if isinstance(state, dict):
self._data = state["_data"]
self.name = state["name"]
self.index = self._data.index
elif isinstance(state, tuple):
# < 0.12 series pickle
nd_state, own_state = state
# recreate the ndarray
data = np.empty(nd_state[1], dtype=nd_state[2])
np.ndarray.__setstate__(data, nd_state)
# backwards compat
index, name = own_state[0], None
if len(own_state) > 1:
name = own_state[1]
# recreate
self._data = SingleBlockManager(data, index, fastpath=True)
self._index = index
self.name = name
else:
raise Exception("cannot unpickle legacy formats -> [%s]" % state)
# indexers
@property
def axes(self):
"""
Return a list of the row axis labels.
"""
return [self.index]
# ----------------------------------------------------------------------
# Indexing Methods
@Appender(generic.NDFrame.take.__doc__)
def take(self, indices, axis=0, is_copy=False, **kwargs):
nv.validate_take(tuple(), kwargs)
indices = ensure_platform_int(indices)
new_index = self.index.take(indices)
if is_categorical_dtype(self):
# https://github.com/pandas-dev/pandas/issues/20664
# TODO: remove when the default Categorical.take behavior changes
indices = maybe_convert_indices(indices, len(self._get_axis(axis)))
kwargs = {"allow_fill": False}
else:
kwargs = {}
new_values = self._values.take(indices, **kwargs)
result = self._constructor(
new_values, index=new_index, fastpath=True
).__finalize__(self)
# Maybe set copy if we didn't actually change the index.
if is_copy:
if not result._get_axis(axis).equals(self._get_axis(axis)):
result._set_is_copy(self)
return result
def _ixs(self, i: int, axis: int = 0):
"""
Return the i-th value or values in the Series by location.
Parameters
----------
i : int
Returns
-------
scalar (int) or Series (slice, sequence)
"""
# dispatch to the values if we need
values = self._values
if isinstance(values, np.ndarray):
return libindex.get_value_at(values, i)
else:
return values[i]
def _slice(self, slobj: slice, axis: int = 0, kind=None):
slobj = self.index._convert_slice_indexer(slobj, kind=kind or "getitem")
return self._get_values(slobj)
def __getitem__(self, key):
key = com.apply_if_callable(key, self)
try:
result = self.index.get_value(self, key)
if not is_scalar(result):
if is_list_like(result) and not isinstance(result, Series):
# we need to box if loc of the key isn't scalar here
# otherwise have inline ndarray/lists
try:
if not is_scalar(self.index.get_loc(key)):
result = self._constructor(
result, index=[key] * len(result), dtype=self.dtype
).__finalize__(self)
except KeyError:
pass
return result
except InvalidIndexError:
pass
except (KeyError, ValueError):
if isinstance(key, tuple) and isinstance(self.index, MultiIndex):
# kludge
pass
elif key is Ellipsis:
return self
elif com.is_bool_indexer(key):
pass
else:
# we can try to coerce the indexer (or this will raise)
new_key = self.index._convert_scalar_indexer(key, kind="getitem")
if type(new_key) != type(key):
return self.__getitem__(new_key)
raise
if is_iterator(key):
key = list(key)
if com.is_bool_indexer(key):
key = check_bool_indexer(self.index, key)
return self._get_with(key)
def _get_with(self, key):
# other: fancy integer or otherwise
if isinstance(key, slice):
return self._slice(key)
elif isinstance(key, ABCDataFrame):
raise TypeError(
"Indexing a Series with DataFrame is not "
"supported, use the appropriate DataFrame column"
)
elif isinstance(key, tuple):
try:
return self._get_values_tuple(key)
except Exception:
if len(key) == 1:
key = key[0]
if isinstance(key, slice):
return self._get_values(key)
raise
if not isinstance(key, (list, np.ndarray, Series, Index)):
key = list(key)
if isinstance(key, Index):
key_type = key.inferred_type
else:
key_type = lib.infer_dtype(key, skipna=False)
if key_type == "integer":
if self.index.is_integer() or self.index.is_floating():
return self.loc[key]
else:
return self._get_values(key)
elif key_type == "boolean":
return self._get_values(key)
if isinstance(key, (list, tuple)):
# TODO: de-dup with tuple case handled above?
# handle the dup indexing case GH#4246
if len(key) == 1 and isinstance(key[0], slice):
# [slice(0, 5, None)] will break if you convert to ndarray,
# e.g. as requested by np.median
# FIXME: hack
return self._get_values(key)
return self.loc[key]
return self.reindex(key)
def _get_values_tuple(self, key):
# mpl hackaround
if com.any_none(*key):
return self._get_values(key)
if not isinstance(self.index, MultiIndex):
raise ValueError("Can only tuple-index with a MultiIndex")
# If key is contained, would have returned by now
indexer, new_index = self.index.get_loc_level(key)
return self._constructor(self._values[indexer], index=new_index).__finalize__(
self
)
def _get_values(self, indexer):
try:
return self._constructor(
self._data.get_slice(indexer), fastpath=True
).__finalize__(self)
except Exception:
return self._values[indexer]
def _get_value(self, label, takeable: bool = False):
"""
Quickly retrieve single value at passed index label.
Parameters
----------
label : object
takeable : interpret the index as indexers, default False
Returns
-------
scalar value
"""
if takeable:
return com.maybe_box_datetimelike(self._values[label])
return self.index.get_value(self._values, label)
def __setitem__(self, key, value):
key = com.apply_if_callable(key, self)
cacher_needs_updating = self._check_is_chained_assignment_possible()
try:
self._set_with_engine(key, value)
except com.SettingWithCopyError:
raise
except (KeyError, ValueError):
values = self._values
if is_integer(key) and not self.index.inferred_type == "integer":
values[key] = value
elif key is Ellipsis:
self[:] = value
else:
self.loc[key] = value
except TypeError as e:
if isinstance(key, tuple) and not isinstance(self.index, MultiIndex):
raise ValueError("Can only tuple-index with a MultiIndex")
# python 3 type errors should be raised
if _is_unorderable_exception(e):
raise IndexError(key)
if com.is_bool_indexer(key):
key = check_bool_indexer(self.index, key)
try:
self._where(~key, value, inplace=True)
return
except InvalidIndexError:
pass
self._set_with(key, value)
if cacher_needs_updating:
self._maybe_update_cacher()
def _set_with_engine(self, key, value):
values = self._values
if is_extension_array_dtype(values.dtype):
# The cython indexing engine does not support ExtensionArrays.
values[self.index.get_loc(key)] = value
return
try:
self.index._engine.set_value(values, key, value)
return
except KeyError:
values[self.index.get_loc(key)] = value
return
def _set_with(self, key, value):
# other: fancy integer or otherwise
if isinstance(key, slice):
indexer = self.index._convert_slice_indexer(key, kind="getitem")
return self._set_values(indexer, value)
elif is_scalar(key) and not is_integer(key) and key not in self.index:
# GH#12862 adding an new key to the Series
# Note: have to exclude integers because that is ambiguously
# position-based
self.loc[key] = value
return
else:
if isinstance(key, tuple):
try:
self._set_values(key, value)
except Exception:
pass
if is_scalar(key):
key = [key]
elif not isinstance(key, (list, Series, np.ndarray)):
try:
key = list(key)
except Exception:
key = [key]
if isinstance(key, Index):
key_type = key.inferred_type
key = key._values
else:
key_type = lib.infer_dtype(key, skipna=False)
if key_type == "integer":
if self.index.inferred_type == "integer":
self._set_labels(key, value)
else:
return self._set_values(key, value)
elif key_type == "boolean":
self._set_values(key.astype(np.bool_), value)
else:
self._set_labels(key, value)
def _set_labels(self, key, value):
key = com.asarray_tuplesafe(key)
indexer = self.index.get_indexer(key)
mask = indexer == -1
if mask.any():
raise ValueError("%s not contained in the index" % str(key[mask]))
self._set_values(indexer, value)
def _set_values(self, key, value):
if isinstance(key, Series):
key = key._values
self._data = self._data.setitem(indexer=key, value=value)
self._maybe_update_cacher()
def _set_value(self, label, value, takeable: bool = False):
"""
Quickly set single value at passed label.
If label is not contained, a new object is created with the label
placed at the end of the result index.
Parameters
----------
label : object
Partial indexing with MultiIndex not allowed
value : object
Scalar value
takeable : interpret the index as indexers, default False
Returns
-------
Series
If label is contained, will be reference to calling Series,
otherwise a new object.
"""
try:
if takeable:
self._values[label] = value
else:
self.index._engine.set_value(self._values, label, value)
except (KeyError, TypeError):
# set using a non-recursive method
self.loc[label] = value
return self
# ----------------------------------------------------------------------
# Unsorted
@property
def _is_mixed_type(self):
return False
def repeat(self, repeats, axis=None):
"""
Repeat elements of a Series.
Returns a new Series where each element of the current Series
is repeated consecutively a given number of times.
Parameters
----------
repeats : int or array of ints
The number of repetitions for each element. This should be a
non-negative integer. Repeating 0 times will return an empty
Series.
axis : None
Must be ``None``. Has no effect but is accepted for compatibility
with numpy.
Returns
-------
Series
Newly created Series with repeated elements.
See Also
--------
Index.repeat : Equivalent function for Index.
numpy.repeat : Similar method for :class:`numpy.ndarray`.
Examples
--------
>>> s = pd.Series(['a', 'b', 'c'])
>>> s
0 a
1 b
2 c
dtype: object
>>> s.repeat(2)
0 a
0 a
1 b
1 b
2 c
2 c
dtype: object
>>> s.repeat([1, 2, 3])
0 a
1 b
1 b
2 c
2 c
2 c
dtype: object
"""
nv.validate_repeat(tuple(), dict(axis=axis))
new_index = self.index.repeat(repeats)
new_values = self._values.repeat(repeats)
return self._constructor(new_values, index=new_index).__finalize__(self)
def reset_index(self, level=None, drop=False, name=None, inplace=False):
"""
Generate a new DataFrame or Series with the index reset.
This is useful when the index needs to be treated as a column, or
when the index is meaningless and needs to be reset to the default
before another operation.
Parameters
----------
level : int, str, tuple, or list, default optional
For a Series with a MultiIndex, only remove the specified levels
from the index. Removes all levels by default.
drop : bool, default False
Just reset the index, without inserting it as a column in
the new DataFrame.
name : object, optional
The name to use for the column containing the original Series
values. Uses ``self.name`` by default. This argument is ignored
when `drop` is True.
inplace : bool, default False
Modify the Series in place (do not create a new object).
Returns
-------
Series or DataFrame
When `drop` is False (the default), a DataFrame is returned.
The newly created columns will come first in the DataFrame,
followed by the original Series values.
When `drop` is True, a `Series` is returned.
In either case, if ``inplace=True``, no value is returned.
See Also
--------
DataFrame.reset_index: Analogous function for DataFrame.
Examples
--------
>>> s = pd.Series([1, 2, 3, 4], name='foo',
... index=pd.Index(['a', 'b', 'c', 'd'], name='idx'))
Generate a DataFrame with default index.
>>> s.reset_index()
idx foo
0 a 1
1 b 2
2 c 3
3 d 4
To specify the name of the new column use `name`.
>>> s.reset_index(name='values')
idx values
0 a 1
1 b 2
2 c 3
3 d 4
To generate a new Series with the default set `drop` to True.
>>> s.reset_index(drop=True)
0 1
1 2
2 3
3 4
Name: foo, dtype: int64
To update the Series in place, without generating a new one
set `inplace` to True. Note that it also requires ``drop=True``.
>>> s.reset_index(inplace=True, drop=True)
>>> s
0 1
1 2
2 3
3 4
Name: foo, dtype: int64
The `level` parameter is interesting for Series with a multi-level
index.
>>> arrays = [np.array(['bar', 'bar', 'baz', 'baz']),
... np.array(['one', 'two', 'one', 'two'])]
>>> s2 = pd.Series(
... range(4), name='foo',
... index=pd.MultiIndex.from_arrays(arrays,
... names=['a', 'b']))
To remove a specific level from the Index, use `level`.
>>> s2.reset_index(level='a')
a foo
b
one bar 0
two bar 1
one baz 2
two baz 3
If `level` is not set, all levels are removed from the Index.
>>> s2.reset_index()
a b foo
0 bar one 0
1 bar two 1
2 baz one 2
3 baz two 3
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if drop:
new_index = ibase.default_index(len(self))
if level is not None:
if not isinstance(level, (tuple, list)):
level = [level]
level = [self.index._get_level_number(lev) for lev in level]
if len(level) < self.index.nlevels:
new_index = self.index.droplevel(level)
if inplace:
self.index = new_index
# set name if it was passed, otherwise, keep the previous name
self.name = name or self.name
else:
return self._constructor(
self._values.copy(), index=new_index
).__finalize__(self)
elif inplace:
raise TypeError(
"Cannot reset_index inplace on a Series to create a DataFrame"
)
else:
df = self.to_frame(name)
return df.reset_index(level=level, drop=drop)
# ----------------------------------------------------------------------
# Rendering Methods
def __repr__(self):
"""
Return a string representation for a particular Series.
"""
buf = StringIO("")
width, height = get_terminal_size()
max_rows = (
height
if get_option("display.max_rows") == 0
else get_option("display.max_rows")
)
min_rows = (
height
if get_option("display.max_rows") == 0
else get_option("display.min_rows")
)
show_dimensions = get_option("display.show_dimensions")
self.to_string(
buf=buf,
name=self.name,
dtype=self.dtype,
min_rows=min_rows,
max_rows=max_rows,
length=show_dimensions,
)
result = buf.getvalue()
return result
def to_string(
self,
buf=None,
na_rep="NaN",
float_format=None,
header=True,
index=True,
length=False,
dtype=False,
name=False,
max_rows=None,
min_rows=None,
):
"""
Render a string representation of the Series.
Parameters
----------
buf : StringIO-like, optional
Buffer to write to.
na_rep : str, optional
String representation of NaN to use, default 'NaN'.
float_format : one-parameter function, optional
Formatter function to apply to columns' elements if they are
floats, default None.
header : bool, default True
Add the Series header (index name).
index : bool, optional
Add index (row) labels, default True.
length : bool, default False
Add the Series length.
dtype : bool, default False
Add the Series dtype.
name : bool, default False
Add the Series name if not None.
max_rows : int, optional
Maximum number of rows to show before truncating. If None, show
all.
min_rows : int, optional
The number of rows to display in a truncated repr (when number
of rows is above `max_rows`).
Returns
-------
str or None
String representation of Series if ``buf=None``, otherwise None.
"""
formatter = fmt.SeriesFormatter(
self,
name=name,
length=length,
header=header,
index=index,
dtype=dtype,
na_rep=na_rep,
float_format=float_format,
min_rows=min_rows,
max_rows=max_rows,
)
result = formatter.to_string()
# catch contract violations
if not isinstance(result, str):
raise AssertionError(
"result must be of type unicode, type"
" of result is {0!r}"
"".format(result.__class__.__name__)
)
if buf is None:
return result
else:
try:
buf.write(result)
except AttributeError:
with open(buf, "w") as f:
f.write(result)
# ----------------------------------------------------------------------
def items(self):
"""
Lazily iterate over (index, value) tuples.
This method returns an iterable tuple (index, value). This is
convenient if you want to create a lazy iterator.
Returns
-------
iterable
Iterable of tuples containing the (index, value) pairs from a
Series.
See Also
--------
DataFrame.items : Iterate over (column name, Series) pairs.
DataFrame.iterrows : Iterate over DataFrame rows as (index, Series) pairs.
Examples
--------
>>> s = pd.Series(['A', 'B', 'C'])
>>> for index, value in s.items():
... print("Index : {}, Value : {}".format(index, value))
Index : 0, Value : A
Index : 1, Value : B
Index : 2, Value : C
"""
return zip(iter(self.index), iter(self))
@Appender(items.__doc__)
def iteritems(self):
return self.items()
# ----------------------------------------------------------------------
# Misc public methods
def keys(self):
"""
Return alias for index.
Returns
-------
Index
Index of the Series.
"""
return self.index
def to_dict(self, into=dict):
"""
Convert Series to {label -> value} dict or dict-like object.
Parameters
----------
into : class, default dict
The collections.abc.Mapping subclass to use as the return
object. Can be the actual class or an empty
instance of the mapping type you want. If you want a
collections.defaultdict, you must pass it initialized.
.. versionadded:: 0.21.0
Returns
-------
collections.abc.Mapping
Key-value representation of Series.
Examples
--------
>>> s = pd.Series([1, 2, 3, 4])
>>> s.to_dict()
{0: 1, 1: 2, 2: 3, 3: 4}
>>> from collections import OrderedDict, defaultdict
>>> s.to_dict(OrderedDict)
OrderedDict([(0, 1), (1, 2), (2, 3), (3, 4)])
>>> dd = defaultdict(list)
>>> s.to_dict(dd)
defaultdict(<class 'list'>, {0: 1, 1: 2, 2: 3, 3: 4})
"""
# GH16122
into_c = com.standardize_mapping(into)
return into_c(self.items())
def to_frame(self, name=None):
"""
Convert Series to DataFrame.
Parameters
----------
name : object, default None
The passed name should substitute for the series name (if it has
one).
Returns
-------
DataFrame
DataFrame representation of Series.
Examples
--------
>>> s = pd.Series(["a", "b", "c"],
... name="vals")
>>> s.to_frame()
vals
0 a
1 b
2 c
"""
if name is None:
df = self._constructor_expanddim(self)
else:
df = self._constructor_expanddim({name: self})
return df
def to_sparse(self, kind="block", fill_value=None):
"""
Convert Series to SparseSeries.
.. deprecated:: 0.25.0
Parameters
----------
kind : {'block', 'integer'}, default 'block'
fill_value : float, defaults to NaN (missing)
Value to use for filling NaN values.
Returns
-------
SparseSeries
Sparse representation of the Series.
"""
warnings.warn(
"Series.to_sparse is deprecated and will be removed in a future version",
FutureWarning,
stacklevel=2,
)
from pandas.core.sparse.series import SparseSeries
values = SparseArray(self, kind=kind, fill_value=fill_value)
with warnings.catch_warnings():
warnings.filterwarnings("ignore", message="SparseSeries")
return SparseSeries(values, index=self.index, name=self.name).__finalize__(
self
)
def _set_name(self, name, inplace=False):
"""
Set the Series name.
Parameters
----------
name : str
inplace : bool
whether to modify `self` directly or return a copy
"""
inplace = validate_bool_kwarg(inplace, "inplace")
ser = self if inplace else self.copy()
ser.name = name
return ser
# ----------------------------------------------------------------------
# Statistics, overridden ndarray methods
# TODO: integrate bottleneck
def count(self, level=None):
"""
Return number of non-NA/null observations in the Series.
Parameters
----------
level : int or level name, default None
If the axis is a MultiIndex (hierarchical), count along a
particular level, collapsing into a smaller Series.
Returns
-------
int or Series (if level specified)
Number of non-null values in the Series.
Examples
--------
>>> s = pd.Series([0.0, 1.0, np.nan])
>>> s.count()
2
"""
if level is None:
return notna(self.array).sum()
if isinstance(level, str):
level = self.index._get_level_number(level)
lev = self.index.levels[level]
level_codes = np.array(self.index.codes[level], subok=False, copy=True)
mask = level_codes == -1
if mask.any():
level_codes[mask] = cnt = len(lev)
lev = lev.insert(cnt, lev._na_value)
obs = level_codes[notna(self.values)]
out = np.bincount(obs, minlength=len(lev) or None)
return self._constructor(out, index=lev, dtype="int64").__finalize__(self)
def mode(self, dropna=True):
"""
Return the mode(s) of the dataset.
Always returns Series even if only one value is returned.
Parameters
----------
dropna : bool, default True
Don't consider counts of NaN/NaT.
.. versionadded:: 0.24.0
Returns
-------
Series
Modes of the Series in sorted order.
"""
# TODO: Add option for bins like value_counts()
return algorithms.mode(self, dropna=dropna)
def unique(self):
"""
Return unique values of Series object.
Uniques are returned in order of appearance. Hash table-based unique,
therefore does NOT sort.
Returns
-------
ndarray or ExtensionArray
The unique values returned as a NumPy array. See Notes.
See Also
--------
unique : Top-level unique method for any 1-d array-like object.
Index.unique : Return Index with unique values from an Index object.
Notes
-----
Returns the unique values as a NumPy array. In case of an
extension-array backed Series, a new
:class:`~api.extensions.ExtensionArray` of that type with just
the unique values is returned. This includes
* Categorical
* Period
* Datetime with Timezone
* Interval
* Sparse
* IntegerNA
See Examples section.
Examples
--------
>>> pd.Series([2, 1, 3, 3], name='A').unique()
array([2, 1, 3])
>>> pd.Series([pd.Timestamp('2016-01-01') for _ in range(3)]).unique()
array(['2016-01-01T00:00:00.000000000'], dtype='datetime64[ns]')
>>> pd.Series([pd.Timestamp('2016-01-01', tz='US/Eastern')
... for _ in range(3)]).unique()
<DatetimeArray>
['2016-01-01 00:00:00-05:00']
Length: 1, dtype: datetime64[ns, US/Eastern]
An unordered Categorical will return categories in the order of
appearance.
>>> pd.Series(pd.Categorical(list('baabc'))).unique()
[b, a, c]
Categories (3, object): [b, a, c]
An ordered Categorical preserves the category ordering.
>>> pd.Series(pd.Categorical(list('baabc'), categories=list('abc'),
... ordered=True)).unique()
[b, a, c]
Categories (3, object): [a < b < c]
"""
result = super().unique()
return result
def drop_duplicates(self, keep="first", inplace=False):
"""
Return Series with duplicate values removed.
Parameters
----------
keep : {'first', 'last', ``False``}, default 'first'
- 'first' : Drop duplicates except for the first occurrence.
- 'last' : Drop duplicates except for the last occurrence.
- ``False`` : Drop all duplicates.
inplace : bool, default ``False``
If ``True``, performs operation inplace and returns None.
Returns
-------
Series
Series with duplicates dropped.
See Also
--------
Index.drop_duplicates : Equivalent method on Index.
DataFrame.drop_duplicates : Equivalent method on DataFrame.
Series.duplicated : Related method on Series, indicating duplicate
Series values.
Examples
--------
Generate a Series with duplicated entries.
>>> s = pd.Series(['lama', 'cow', 'lama', 'beetle', 'lama', 'hippo'],
... name='animal')
>>> s
0 lama
1 cow
2 lama
3 beetle
4 lama
5 hippo
Name: animal, dtype: object
With the 'keep' parameter, the selection behaviour of duplicated values
can be changed. The value 'first' keeps the first occurrence for each
set of duplicated entries. The default value of keep is 'first'.
>>> s.drop_duplicates()
0 lama
1 cow
3 beetle
5 hippo
Name: animal, dtype: object
The value 'last' for parameter 'keep' keeps the last occurrence for
each set of duplicated entries.
>>> s.drop_duplicates(keep='last')
1 cow
3 beetle
4 lama
5 hippo
Name: animal, dtype: object
The value ``False`` for parameter 'keep' discards all sets of
duplicated entries. Setting the value of 'inplace' to ``True`` performs
the operation inplace and returns ``None``.
>>> s.drop_duplicates(keep=False, inplace=True)
>>> s
1 cow
3 beetle
5 hippo
Name: animal, dtype: object
"""
return super().drop_duplicates(keep=keep, inplace=inplace)
def duplicated(self, keep="first"):
"""
Indicate duplicate Series values.
Duplicated values are indicated as ``True`` values in the resulting
Series. Either all duplicates, all except the first or all except the
last occurrence of duplicates can be indicated.
Parameters
----------
keep : {'first', 'last', False}, default 'first'
- 'first' : Mark duplicates as ``True`` except for the first
occurrence.
- 'last' : Mark duplicates as ``True`` except for the last
occurrence.
- ``False`` : Mark all duplicates as ``True``.
Returns
-------
Series
Series indicating whether each value has occurred in the
preceding values.
See Also
--------
Index.duplicated : Equivalent method on pandas.Index.
DataFrame.duplicated : Equivalent method on pandas.DataFrame.
Series.drop_duplicates : Remove duplicate values from Series.
Examples
--------
By default, for each set of duplicated values, the first occurrence is
set on False and all others on True:
>>> animals = pd.Series(['lama', 'cow', 'lama', 'beetle', 'lama'])
>>> animals.duplicated()
0 False
1 False
2 True
3 False
4 True
dtype: bool
which is equivalent to
>>> animals.duplicated(keep='first')
0 False
1 False
2 True
3 False
4 True
dtype: bool
By using 'last', the last occurrence of each set of duplicated values
is set on False and all others on True:
>>> animals.duplicated(keep='last')
0 True
1 False
2 True
3 False
4 False
dtype: bool
By setting keep on ``False``, all duplicates are True:
>>> animals.duplicated(keep=False)
0 True
1 False
2 True
3 False
4 True
dtype: bool
"""
return super().duplicated(keep=keep)
def idxmin(self, axis=0, skipna=True, *args, **kwargs):
"""
Return the row label of the minimum value.
If multiple values equal the minimum, the first row label with that
value is returned.
Parameters
----------
skipna : bool, default True
Exclude NA/null values. If the entire Series is NA, the result
will be NA.
axis : int, default 0
For compatibility with DataFrame.idxmin. Redundant for application
on Series.
*args, **kwargs
Additional keywords have no effect but might be accepted
for compatibility with NumPy.
Returns
-------
Index
Label of the minimum value.
Raises
------
ValueError
If the Series is empty.
See Also
--------
numpy.argmin : Return indices of the minimum values
along the given axis.
DataFrame.idxmin : Return index of first occurrence of minimum
over requested axis.
Series.idxmax : Return index *label* of the first occurrence
of maximum of values.
Notes
-----
This method is the Series version of ``ndarray.argmin``. This method
returns the label of the minimum, while ``ndarray.argmin`` returns
the position. To get the position, use ``series.values.argmin()``.
Examples
--------
>>> s = pd.Series(data=[1, None, 4, 1],
... index=['A', 'B', 'C', 'D'])
>>> s
A 1.0
B NaN
C 4.0
D 1.0
dtype: float64
>>> s.idxmin()
'A'
If `skipna` is False and there is an NA value in the data,
the function returns ``nan``.
>>> s.idxmin(skipna=False)
nan
"""
skipna = nv.validate_argmin_with_skipna(skipna, args, kwargs)
i = nanops.nanargmin(com.values_from_object(self), skipna=skipna)
if i == -1:
return np.nan
return self.index[i]
def idxmax(self, axis=0, skipna=True, *args, **kwargs):
"""
Return the row label of the maximum value.
If multiple values equal the maximum, the first row label with that
value is returned.
Parameters
----------
skipna : bool, default True
Exclude NA/null values. If the entire Series is NA, the result
will be NA.
axis : int, default 0
For compatibility with DataFrame.idxmax. Redundant for application
on Series.
*args, **kwargs
Additional keywords have no effect but might be accepted
for compatibility with NumPy.
Returns
-------
Index
Label of the maximum value.
Raises
------
ValueError
If the Series is empty.
See Also
--------
numpy.argmax : Return indices of the maximum values
along the given axis.
DataFrame.idxmax : Return index of first occurrence of maximum
over requested axis.
Series.idxmin : Return index *label* of the first occurrence
of minimum of values.
Notes
-----
This method is the Series version of ``ndarray.argmax``. This method
returns the label of the maximum, while ``ndarray.argmax`` returns
the position. To get the position, use ``series.values.argmax()``.
Examples
--------
>>> s = pd.Series(data=[1, None, 4, 3, 4],
... index=['A', 'B', 'C', 'D', 'E'])
>>> s
A 1.0
B NaN
C 4.0
D 3.0
E 4.0
dtype: float64
>>> s.idxmax()
'C'
If `skipna` is False and there is an NA value in the data,
the function returns ``nan``.
>>> s.idxmax(skipna=False)
nan
"""
skipna = nv.validate_argmax_with_skipna(skipna, args, kwargs)
i = nanops.nanargmax(com.values_from_object(self), skipna=skipna)
if i == -1:
return np.nan
return self.index[i]
# ndarray compat
argmin = deprecate(
"argmin",
idxmin,
"0.21.0",
msg=dedent(
"""
The current behaviour of 'Series.argmin' is deprecated, use 'idxmin'
instead.
The behavior of 'argmin' will be corrected to return the positional
minimum in the future. For now, use 'series.values.argmin' or
'np.argmin(np.array(values))' to get the position of the minimum
row."""
),
)
argmax = deprecate(
"argmax",
idxmax,
"0.21.0",
msg=dedent(
"""
The current behaviour of 'Series.argmax' is deprecated, use 'idxmax'
instead.
The behavior of 'argmax' will be corrected to return the positional
maximum in the future. For now, use 'series.values.argmax' or
'np.argmax(np.array(values))' to get the position of the maximum
row."""
),
)
def round(self, decimals=0, *args, **kwargs):
"""
Round each value in a Series to the given number of decimals.
Parameters
----------
decimals : int
Number of decimal places to round to (default: 0).
If decimals is negative, it specifies the number of
positions to the left of the decimal point.
Returns
-------
Series
Rounded values of the Series.
See Also
--------
numpy.around : Round values of an np.array.
DataFrame.round : Round values of a DataFrame.
Examples
--------
>>> s = pd.Series([0.1, 1.3, 2.7])
>>> s.round()
0 0.0
1 1.0
2 3.0
dtype: float64
"""
nv.validate_round(args, kwargs)
result = com.values_from_object(self).round(decimals)
result = self._constructor(result, index=self.index).__finalize__(self)
return result
def quantile(self, q=0.5, interpolation="linear"):
"""
Return value at the given quantile.
Parameters
----------
q : float or array-like, default 0.5 (50% quantile)
0 <= q <= 1, the quantile(s) to compute.
interpolation : {'linear', 'lower', 'higher', 'midpoint', 'nearest'}
This optional parameter specifies the interpolation method to use,
when the desired quantile lies between two data points `i` and `j`:
* linear: `i + (j - i) * fraction`, where `fraction` is the
fractional part of the index surrounded by `i` and `j`.
* lower: `i`.
* higher: `j`.
* nearest: `i` or `j` whichever is nearest.
* midpoint: (`i` + `j`) / 2.
Returns
-------
float or Series
If ``q`` is an array, a Series will be returned where the
index is ``q`` and the values are the quantiles, otherwise
a float will be returned.
See Also
--------
core.window.Rolling.quantile
numpy.percentile
Examples
--------
>>> s = pd.Series([1, 2, 3, 4])
>>> s.quantile(.5)
2.5
>>> s.quantile([.25, .5, .75])
0.25 1.75
0.50 2.50
0.75 3.25
dtype: float64
"""
self._check_percentile(q)
# We dispatch to DataFrame so that core.internals only has to worry
# about 2D cases.
df = self.to_frame()
result = df.quantile(q=q, interpolation=interpolation, numeric_only=False)
if result.ndim == 2:
result = result.iloc[:, 0]
if is_list_like(q):
result.name = self.name
return self._constructor(result, index=Float64Index(q), name=self.name)
else:
# scalar
return result.iloc[0]
def corr(self, other, method="pearson", min_periods=None):
"""
Compute correlation with `other` Series, excluding missing values.
Parameters
----------
other : Series
Series with which to compute the correlation.
method : {'pearson', 'kendall', 'spearman'} or callable
* pearson : standard correlation coefficient
* kendall : Kendall Tau correlation coefficient
* spearman : Spearman rank correlation
* callable: callable with input two 1d ndarrays
and returning a float. Note that the returned matrix from corr
will have 1 along the diagonals and will be symmetric
regardless of the callable's behavior
.. versionadded:: 0.24.0
min_periods : int, optional
Minimum number of observations needed to have a valid result.
Returns
-------
float
Correlation with other.
Examples
--------
>>> def histogram_intersection(a, b):
... v = np.minimum(a, b).sum().round(decimals=1)
... return v
>>> s1 = pd.Series([.2, .0, .6, .2])
>>> s2 = pd.Series([.3, .6, .0, .1])
>>> s1.corr(s2, method=histogram_intersection)
0.3
"""
this, other = self.align(other, join="inner", copy=False)
if len(this) == 0:
return np.nan
if method in ["pearson", "spearman", "kendall"] or callable(method):
return nanops.nancorr(
this.values, other.values, method=method, min_periods=min_periods
)
raise ValueError(
"method must be either 'pearson', "
"'spearman', 'kendall', or a callable, "
"'{method}' was supplied".format(method=method)
)
def cov(self, other, min_periods=None):
"""
Compute covariance with Series, excluding missing values.
Parameters
----------
other : Series
Series with which to compute the covariance.
min_periods : int, optional
Minimum number of observations needed to have a valid result.
Returns
-------
float
Covariance between Series and other normalized by N-1
(unbiased estimator).
Examples
--------
>>> s1 = pd.Series([0.90010907, 0.13484424, 0.62036035])
>>> s2 = pd.Series([0.12528585, 0.26962463, 0.51111198])
>>> s1.cov(s2)
-0.01685762652715874
"""
this, other = self.align(other, join="inner", copy=False)
if len(this) == 0:
return np.nan
return nanops.nancov(this.values, other.values, min_periods=min_periods)
def diff(self, periods=1):
"""
First discrete difference of element.
Calculates the difference of a Series element compared with another
element in the Series (default is element in previous row).
Parameters
----------
periods : int, default 1
Periods to shift for calculating difference, accepts negative
values.
Returns
-------
Series
First differences of the Series.
See Also
--------
Series.pct_change: Percent change over given number of periods.
Series.shift: Shift index by desired number of periods with an
optional time freq.
DataFrame.diff: First discrete difference of object.
Examples
--------
Difference with previous row
>>> s = pd.Series([1, 1, 2, 3, 5, 8])
>>> s.diff()
0 NaN
1 0.0
2 1.0
3 1.0
4 2.0
5 3.0
dtype: float64
Difference with 3rd previous row
>>> s.diff(periods=3)
0 NaN
1 NaN
2 NaN
3 2.0
4 4.0
5 6.0
dtype: float64
Difference with following row
>>> s.diff(periods=-1)
0 0.0
1 -1.0
2 -1.0
3 -2.0
4 -3.0
5 NaN
dtype: float64
"""
result = algorithms.diff(com.values_from_object(self), periods)
return self._constructor(result, index=self.index).__finalize__(self)
def autocorr(self, lag=1):
"""
Compute the lag-N autocorrelation.
This method computes the Pearson correlation between
the Series and its shifted self.
Parameters
----------
lag : int, default 1
Number of lags to apply before performing autocorrelation.
Returns
-------
float
The Pearson correlation between self and self.shift(lag).
See Also
--------
Series.corr : Compute the correlation between two Series.
Series.shift : Shift index by desired number of periods.
DataFrame.corr : Compute pairwise correlation of columns.
DataFrame.corrwith : Compute pairwise correlation between rows or
columns of two DataFrame objects.
Notes
-----
If the Pearson correlation is not well defined return 'NaN'.
Examples
--------
>>> s = pd.Series([0.25, 0.5, 0.2, -0.05])
>>> s.autocorr() # doctest: +ELLIPSIS
0.10355...
>>> s.autocorr(lag=2) # doctest: +ELLIPSIS
-0.99999...
If the Pearson correlation is not well defined, then 'NaN' is returned.
>>> s = pd.Series([1, 0, 0, 0])
>>> s.autocorr()
nan
"""
return self.corr(self.shift(lag))
def dot(self, other):
"""
Compute the dot product between the Series and the columns of other.
This method computes the dot product between the Series and another
one, or the Series and each columns of a DataFrame, or the Series and
each columns of an array.
It can also be called using `self @ other` in Python >= 3.5.
Parameters
----------
other : Series, DataFrame or array-like
The other object to compute the dot product with its columns.
Returns
-------
scalar, Series or numpy.ndarray
Return the dot product of the Series and other if other is a
Series, the Series of the dot product of Series and each rows of
other if other is a DataFrame or a numpy.ndarray between the Series
and each columns of the numpy array.
See Also
--------
DataFrame.dot: Compute the matrix product with the DataFrame.
Series.mul: Multiplication of series and other, element-wise.
Notes
-----
The Series and other has to share the same index if other is a Series
or a DataFrame.
Examples
--------
>>> s = pd.Series([0, 1, 2, 3])
>>> other = pd.Series([-1, 2, -3, 4])
>>> s.dot(other)
8
>>> s @ other
8
>>> df = pd.DataFrame([[0, 1], [-2, 3], [4, -5], [6, 7]])
>>> s.dot(df)
0 24
1 14
dtype: int64
>>> arr = np.array([[0, 1], [-2, 3], [4, -5], [6, 7]])
>>> s.dot(arr)
array([24, 14])
"""
if isinstance(other, (Series, ABCDataFrame)):
common = self.index.union(other.index)
if len(common) > len(self.index) or len(common) > len(other.index):
raise ValueError("matrices are not aligned")
left = self.reindex(index=common, copy=False)
right = other.reindex(index=common, copy=False)
lvals = left.values
rvals = right.values
else:
lvals = self.values
rvals = np.asarray(other)
if lvals.shape[0] != rvals.shape[0]:
raise Exception(
"Dot product shape mismatch, %s vs %s" % (lvals.shape, rvals.shape)
)
if isinstance(other, ABCDataFrame):
return self._constructor(
np.dot(lvals, rvals), index=other.columns
).__finalize__(self)
elif isinstance(other, Series):
return np.dot(lvals, rvals)
elif isinstance(rvals, np.ndarray):
return np.dot(lvals, rvals)
else: # pragma: no cover
raise TypeError("unsupported type: %s" % type(other))
def __matmul__(self, other):
"""
Matrix multiplication using binary `@` operator in Python>=3.5.
"""
return self.dot(other)
def __rmatmul__(self, other):
"""
Matrix multiplication using binary `@` operator in Python>=3.5.
"""
return self.dot(np.transpose(other))
@Substitution(klass="Series")
@Appender(base._shared_docs["searchsorted"])
def searchsorted(self, value, side="left", sorter=None):
return algorithms.searchsorted(self._values, value, side=side, sorter=sorter)
# -------------------------------------------------------------------
# Combination
def append(self, to_append, ignore_index=False, verify_integrity=False):
"""
Concatenate two or more Series.
Parameters
----------
to_append : Series or list/tuple of Series
Series to append with self.
ignore_index : bool, default False
If True, do not use the index labels.
verify_integrity : bool, default False
If True, raise Exception on creating index with duplicates.
Returns
-------
Series
Concatenated Series.
See Also
--------
concat : General function to concatenate DataFrame or Series objects.
Notes
-----
Iteratively appending to a Series can be more computationally intensive
than a single concatenate. A better solution is to append values to a
list and then concatenate the list with the original Series all at
once.
Examples
--------
>>> s1 = pd.Series([1, 2, 3])
>>> s2 = pd.Series([4, 5, 6])
>>> s3 = pd.Series([4, 5, 6], index=[3, 4, 5])
>>> s1.append(s2)
0 1
1 2
2 3
0 4
1 5
2 6
dtype: int64
>>> s1.append(s3)
0 1
1 2
2 3
3 4
4 5
5 6
dtype: int64
With `ignore_index` set to True:
>>> s1.append(s2, ignore_index=True)
0 1
1 2
2 3
3 4
4 5
5 6
dtype: int64
With `verify_integrity` set to True:
>>> s1.append(s2, verify_integrity=True)
Traceback (most recent call last):
...
ValueError: Indexes have overlapping values: [0, 1, 2]
"""
from pandas.core.reshape.concat import concat
if isinstance(to_append, (list, tuple)):
to_concat = [self] + to_append
else:
to_concat = [self, to_append]
return concat(
to_concat, ignore_index=ignore_index, verify_integrity=verify_integrity
)
def _binop(self, other, func, level=None, fill_value=None):
"""
Perform generic binary operation with optional fill value.
Parameters
----------
other : Series
func : binary operator
fill_value : float or object
Value to substitute for NA/null values. If both Series are NA in a
location, the result will be NA regardless of the passed fill value
level : int or level name, default None
Broadcast across a level, matching Index values on the
passed MultiIndex level
Returns
-------
Series
"""
if not isinstance(other, Series):
raise AssertionError("Other operand must be Series")
new_index = self.index
this = self
if not self.index.equals(other.index):
this, other = self.align(other, level=level, join="outer", copy=False)
new_index = this.index
this_vals, other_vals = ops.fill_binop(this.values, other.values, fill_value)
with np.errstate(all="ignore"):
result = func(this_vals, other_vals)
name = ops.get_op_result_name(self, other)
if func.__name__ in ["divmod", "rdivmod"]:
ret = ops._construct_divmod_result(self, result, new_index, name)
else:
ret = ops._construct_result(self, result, new_index, name)
return ret
def combine(self, other, func, fill_value=None):
"""
Combine the Series with a Series or scalar according to `func`.
Combine the Series and `other` using `func` to perform elementwise
selection for combined Series.
`fill_value` is assumed when value is missing at some index
from one of the two objects being combined.
Parameters
----------
other : Series or scalar
The value(s) to be combined with the `Series`.
func : function
Function that takes two scalars as inputs and returns an element.
fill_value : scalar, optional
The value to assume when an index is missing from
one Series or the other. The default specifies to use the
appropriate NaN value for the underlying dtype of the Series.
Returns
-------
Series
The result of combining the Series with the other object.
See Also
--------
Series.combine_first : Combine Series values, choosing the calling
Series' values first.
Examples
--------
Consider 2 Datasets ``s1`` and ``s2`` containing
highest clocked speeds of different birds.
>>> s1 = pd.Series({'falcon': 330.0, 'eagle': 160.0})
>>> s1
falcon 330.0
eagle 160.0
dtype: float64
>>> s2 = pd.Series({'falcon': 345.0, 'eagle': 200.0, 'duck': 30.0})
>>> s2
falcon 345.0
eagle 200.0
duck 30.0
dtype: float64
Now, to combine the two datasets and view the highest speeds
of the birds across the two datasets
>>> s1.combine(s2, max)
duck NaN
eagle 200.0
falcon 345.0
dtype: float64
In the previous example, the resulting value for duck is missing,
because the maximum of a NaN and a float is a NaN.
So, in the example, we set ``fill_value=0``,
so the maximum value returned will be the value from some dataset.
>>> s1.combine(s2, max, fill_value=0)
duck 30.0
eagle 200.0
falcon 345.0
dtype: float64
"""
if fill_value is None:
fill_value = na_value_for_dtype(self.dtype, compat=False)
if isinstance(other, Series):
# If other is a Series, result is based on union of Series,
# so do this element by element
new_index = self.index.union(other.index)
new_name = ops.get_op_result_name(self, other)
new_values = []
for idx in new_index:
lv = self.get(idx, fill_value)
rv = other.get(idx, fill_value)
with np.errstate(all="ignore"):
new_values.append(func(lv, rv))
else:
# Assume that other is a scalar, so apply the function for
# each element in the Series
new_index = self.index
with np.errstate(all="ignore"):
new_values = [func(lv, other) for lv in self._values]
new_name = self.name
if is_categorical_dtype(self.values):
pass
elif is_extension_array_dtype(self.values):
# The function can return something of any type, so check
# if the type is compatible with the calling EA.
try:
new_values = self._values._from_sequence(new_values)
except Exception:
# https://github.com/pandas-dev/pandas/issues/22850
# pandas has no control over what 3rd-party ExtensionArrays
# do in _values_from_sequence. We still want ops to work
# though, so we catch any regular Exception.
pass
return self._constructor(new_values, index=new_index, name=new_name)
def combine_first(self, other):
"""
Combine Series values, choosing the calling Series's values first.
Parameters
----------
other : Series
The value(s) to be combined with the `Series`.
Returns
-------
Series
The result of combining the Series with the other object.
See Also
--------
Series.combine : Perform elementwise operation on two Series
using a given function.
Notes
-----
Result index will be the union of the two indexes.
Examples
--------
>>> s1 = pd.Series([1, np.nan])
>>> s2 = pd.Series([3, 4])
>>> s1.combine_first(s2)
0 1.0
1 4.0
dtype: float64
"""
new_index = self.index.union(other.index)
this = self.reindex(new_index, copy=False)
other = other.reindex(new_index, copy=False)
if is_datetimelike(this) and not is_datetimelike(other):
other = to_datetime(other)
return this.where(notna(this), other)
def update(self, other):
"""
Modify Series in place using non-NA values from passed
Series. Aligns on index.
Parameters
----------
other : Series
Examples
--------
>>> s = pd.Series([1, 2, 3])
>>> s.update(pd.Series([4, 5, 6]))
>>> s
0 4
1 5
2 6
dtype: int64
>>> s = pd.Series(['a', 'b', 'c'])
>>> s.update(pd.Series(['d', 'e'], index=[0, 2]))
>>> s
0 d
1 b
2 e
dtype: object
>>> s = pd.Series([1, 2, 3])
>>> s.update(pd.Series([4, 5, 6, 7, 8]))
>>> s
0 4
1 5
2 6
dtype: int64
If ``other`` contains NaNs the corresponding values are not updated
in the original Series.
>>> s = pd.Series([1, 2, 3])
>>> s.update(pd.Series([4, np.nan, 6]))
>>> s
0 4
1 2
2 6
dtype: int64
"""
other = other.reindex_like(self)
mask = notna(other)
self._data = self._data.putmask(mask=mask, new=other, inplace=True)
self._maybe_update_cacher()
# ----------------------------------------------------------------------
# Reindexing, sorting
def sort_values(
self,
axis=0,
ascending=True,
inplace=False,
kind="quicksort",
na_position="last",
):
"""
Sort by the values.
Sort a Series in ascending or descending order by some
criterion.
Parameters
----------
axis : {0 or 'index'}, default 0
Axis to direct sorting. The value 'index' is accepted for
compatibility with DataFrame.sort_values.
ascending : bool, default True
If True, sort values in ascending order, otherwise descending.
inplace : bool, default False
If True, perform operation in-place.
kind : {'quicksort', 'mergesort' or 'heapsort'}, default 'quicksort'
Choice of sorting algorithm. See also :func:`numpy.sort` for more
information. 'mergesort' is the only stable algorithm.
na_position : {'first' or 'last'}, default 'last'
Argument 'first' puts NaNs at the beginning, 'last' puts NaNs at
the end.
Returns
-------
Series
Series ordered by values.
See Also
--------
Series.sort_index : Sort by the Series indices.
DataFrame.sort_values : Sort DataFrame by the values along either axis.
DataFrame.sort_index : Sort DataFrame by indices.
Examples
--------
>>> s = pd.Series([np.nan, 1, 3, 10, 5])
>>> s
0 NaN
1 1.0
2 3.0
3 10.0
4 5.0
dtype: float64
Sort values ascending order (default behaviour)
>>> s.sort_values(ascending=True)
1 1.0
2 3.0
4 5.0
3 10.0
0 NaN
dtype: float64
Sort values descending order
>>> s.sort_values(ascending=False)
3 10.0
4 5.0
2 3.0
1 1.0
0 NaN
dtype: float64
Sort values inplace
>>> s.sort_values(ascending=False, inplace=True)
>>> s
3 10.0
4 5.0
2 3.0
1 1.0
0 NaN
dtype: float64
Sort values putting NAs first
>>> s.sort_values(na_position='first')
0 NaN
1 1.0
2 3.0
4 5.0
3 10.0
dtype: float64
Sort a series of strings
>>> s = pd.Series(['z', 'b', 'd', 'a', 'c'])
>>> s
0 z
1 b
2 d
3 a
4 c
dtype: object
>>> s.sort_values()
3 a
1 b
4 c
2 d
0 z
dtype: object
"""
inplace = validate_bool_kwarg(inplace, "inplace")
# Validate the axis parameter
self._get_axis_number(axis)
# GH 5856/5853
if inplace and self._is_cached:
raise ValueError(
"This Series is a view of some other array, to "
"sort in-place you must create a copy"
)
def _try_kind_sort(arr):
# easier to ask forgiveness than permission
try:
# if kind==mergesort, it can fail for object dtype
return arr.argsort(kind=kind)
except TypeError:
# stable sort not available for object dtype
# uses the argsort default quicksort
return arr.argsort(kind="quicksort")
arr = self._values
sortedIdx = np.empty(len(self), dtype=np.int32)
bad = isna(arr)
good = ~bad
idx = ibase.default_index(len(self))
argsorted = _try_kind_sort(arr[good])
if is_list_like(ascending):
if len(ascending) != 1:
raise ValueError(
"Length of ascending (%d) must be 1 "
"for Series" % (len(ascending))
)
ascending = ascending[0]
if not is_bool(ascending):
raise ValueError("ascending must be boolean")
if not ascending:
argsorted = argsorted[::-1]
if na_position == "last":
n = good.sum()
sortedIdx[:n] = idx[good][argsorted]
sortedIdx[n:] = idx[bad]
elif na_position == "first":
n = bad.sum()
sortedIdx[n:] = idx[good][argsorted]
sortedIdx[:n] = idx[bad]
else:
raise ValueError("invalid na_position: {!r}".format(na_position))
result = self._constructor(arr[sortedIdx], index=self.index[sortedIdx])
if inplace:
self._update_inplace(result)
else:
return result.__finalize__(self)
def sort_index(
self,
axis=0,
level=None,
ascending=True,
inplace=False,
kind="quicksort",
na_position="last",
sort_remaining=True,
):
"""
Sort Series by index labels.
Returns a new Series sorted by label if `inplace` argument is
``False``, otherwise updates the original series and returns None.
Parameters
----------
axis : int, default 0
Axis to direct sorting. This can only be 0 for Series.
level : int, optional
If not None, sort on values in specified index level(s).
ascending : bool, default true
Sort ascending vs. descending.
inplace : bool, default False
If True, perform operation in-place.
kind : {'quicksort', 'mergesort', 'heapsort'}, default 'quicksort'
Choice of sorting algorithm. See also :func:`numpy.sort` for more
information. 'mergesort' is the only stable algorithm. For
DataFrames, this option is only applied when sorting on a single
column or label.
na_position : {'first', 'last'}, default 'last'
If 'first' puts NaNs at the beginning, 'last' puts NaNs at the end.
Not implemented for MultiIndex.
sort_remaining : bool, default True
If True and sorting by level and index is multilevel, sort by other
levels too (in order) after sorting by specified level.
Returns
-------
Series
The original Series sorted by the labels.
See Also
--------
DataFrame.sort_index: Sort DataFrame by the index.
DataFrame.sort_values: Sort DataFrame by the value.
Series.sort_values : Sort Series by the value.
Examples
--------
>>> s = pd.Series(['a', 'b', 'c', 'd'], index=[3, 2, 1, 4])
>>> s.sort_index()
1 c
2 b
3 a
4 d
dtype: object
Sort Descending
>>> s.sort_index(ascending=False)
4 d
3 a
2 b
1 c
dtype: object
Sort Inplace
>>> s.sort_index(inplace=True)
>>> s
1 c
2 b
3 a
4 d
dtype: object
By default NaNs are put at the end, but use `na_position` to place
them at the beginning
>>> s = pd.Series(['a', 'b', 'c', 'd'], index=[3, 2, 1, np.nan])
>>> s.sort_index(na_position='first')
NaN d
1.0 c
2.0 b
3.0 a
dtype: object
Specify index level to sort
>>> arrays = [np.array(['qux', 'qux', 'foo', 'foo',
... 'baz', 'baz', 'bar', 'bar']),
... np.array(['two', 'one', 'two', 'one',
... 'two', 'one', 'two', 'one'])]
>>> s = pd.Series([1, 2, 3, 4, 5, 6, 7, 8], index=arrays)
>>> s.sort_index(level=1)
bar one 8
baz one 6
foo one 4
qux one 2
bar two 7
baz two 5
foo two 3
qux two 1
dtype: int64
Does not sort by remaining levels when sorting by levels
>>> s.sort_index(level=1, sort_remaining=False)
qux one 2
foo one 4
baz one 6
bar one 8
qux two 1
foo two 3
baz two 5
bar two 7
dtype: int64
"""
# TODO: this can be combined with DataFrame.sort_index impl as
# almost identical
inplace = validate_bool_kwarg(inplace, "inplace")
# Validate the axis parameter
self._get_axis_number(axis)
index = self.index
if level is not None:
new_index, indexer = index.sortlevel(
level, ascending=ascending, sort_remaining=sort_remaining
)
elif isinstance(index, MultiIndex):
from pandas.core.sorting import lexsort_indexer
labels = index._sort_levels_monotonic()
indexer = lexsort_indexer(
labels._get_codes_for_sorting(),
orders=ascending,
na_position=na_position,
)
else:
from pandas.core.sorting import nargsort
# Check monotonic-ness before sort an index
# GH11080
if (ascending and index.is_monotonic_increasing) or (
not ascending and index.is_monotonic_decreasing
):
if inplace:
return
else:
return self.copy()
indexer = nargsort(
index, kind=kind, ascending=ascending, na_position=na_position
)
indexer = ensure_platform_int(indexer)
new_index = index.take(indexer)
new_index = new_index._sort_levels_monotonic()
new_values = self._values.take(indexer)
result = self._constructor(new_values, index=new_index)
if inplace:
self._update_inplace(result)
else:
return result.__finalize__(self)
def argsort(self, axis=0, kind="quicksort", order=None):
"""
Override ndarray.argsort. Argsorts the value, omitting NA/null values,
and places the result in the same locations as the non-NA values.
Parameters
----------
axis : int
Has no effect but is accepted for compatibility with numpy.
kind : {'mergesort', 'quicksort', 'heapsort'}, default 'quicksort'
Choice of sorting algorithm. See np.sort for more
information. 'mergesort' is the only stable algorithm
order : None
Has no effect but is accepted for compatibility with numpy.
Returns
-------
Series
Positions of values within the sort order with -1 indicating
nan values.
See Also
--------
numpy.ndarray.argsort
"""
values = self._values
mask = isna(values)
if mask.any():
result = Series(-1, index=self.index, name=self.name, dtype="int64")
notmask = ~mask
result[notmask] = np.argsort(values[notmask], kind=kind)
return self._constructor(result, index=self.index).__finalize__(self)
else:
return self._constructor(
np.argsort(values, kind=kind), index=self.index, dtype="int64"
).__finalize__(self)
def nlargest(self, n=5, keep="first"):
"""
Return the largest `n` elements.
Parameters
----------
n : int, default 5
Return this many descending sorted values.
keep : {'first', 'last', 'all'}, default 'first'
When there are duplicate values that cannot all fit in a
Series of `n` elements:
- ``first`` : return the first `n` occurrences in order
of appearance.
- ``last`` : return the last `n` occurrences in reverse
order of appearance.
- ``all`` : keep all occurrences. This can result in a Series of
size larger than `n`.
Returns
-------
Series
The `n` largest values in the Series, sorted in decreasing order.
See Also
--------
Series.nsmallest: Get the `n` smallest elements.
Series.sort_values: Sort Series by values.
Series.head: Return the first `n` rows.
Notes
-----
Faster than ``.sort_values(ascending=False).head(n)`` for small `n`
relative to the size of the ``Series`` object.
Examples
--------
>>> countries_population = {"Italy": 59000000, "France": 65000000,
... "Malta": 434000, "Maldives": 434000,
... "Brunei": 434000, "Iceland": 337000,
... "Nauru": 11300, "Tuvalu": 11300,
... "Anguilla": 11300, "Monserat": 5200}
>>> s = pd.Series(countries_population)
>>> s
Italy 59000000
France 65000000
Malta 434000
Maldives 434000
Brunei 434000
Iceland 337000
Nauru 11300
Tuvalu 11300
Anguilla 11300
Monserat 5200
dtype: int64
The `n` largest elements where ``n=5`` by default.
>>> s.nlargest()
France 65000000
Italy 59000000
Malta 434000
Maldives 434000
Brunei 434000
dtype: int64
The `n` largest elements where ``n=3``. Default `keep` value is 'first'
so Malta will be kept.
>>> s.nlargest(3)
France 65000000
Italy 59000000
Malta 434000
dtype: int64
The `n` largest elements where ``n=3`` and keeping the last duplicates.
Brunei will be kept since it is the last with value 434000 based on
the index order.
>>> s.nlargest(3, keep='last')
France 65000000
Italy 59000000
Brunei 434000
dtype: int64
The `n` largest elements where ``n=3`` with all duplicates kept. Note
that the returned Series has five elements due to the three duplicates.
>>> s.nlargest(3, keep='all')
France 65000000
Italy 59000000
Malta 434000
Maldives 434000
Brunei 434000
dtype: int64
"""
return algorithms.SelectNSeries(self, n=n, keep=keep).nlargest()
def nsmallest(self, n=5, keep="first"):
"""
Return the smallest `n` elements.
Parameters
----------
n : int, default 5
Return this many ascending sorted values.
keep : {'first', 'last', 'all'}, default 'first'
When there are duplicate values that cannot all fit in a
Series of `n` elements:
- ``first`` : return the first `n` occurrences in order
of appearance.
- ``last`` : return the last `n` occurrences in reverse
order of appearance.
- ``all`` : keep all occurrences. This can result in a Series of
size larger than `n`.
Returns
-------
Series
The `n` smallest values in the Series, sorted in increasing order.
See Also
--------
Series.nlargest: Get the `n` largest elements.
Series.sort_values: Sort Series by values.
Series.head: Return the first `n` rows.
Notes
-----
Faster than ``.sort_values().head(n)`` for small `n` relative to
the size of the ``Series`` object.
Examples
--------
>>> countries_population = {"Italy": 59000000, "France": 65000000,
... "Brunei": 434000, "Malta": 434000,
... "Maldives": 434000, "Iceland": 337000,
... "Nauru": 11300, "Tuvalu": 11300,
... "Anguilla": 11300, "Monserat": 5200}
>>> s = pd.Series(countries_population)
>>> s
Italy 59000000
France 65000000
Brunei 434000
Malta 434000
Maldives 434000
Iceland 337000
Nauru 11300
Tuvalu 11300
Anguilla 11300
Monserat 5200
dtype: int64
The `n` smallest elements where ``n=5`` by default.
>>> s.nsmallest()
Monserat 5200
Nauru 11300
Tuvalu 11300
Anguilla 11300
Iceland 337000
dtype: int64
The `n` smallest elements where ``n=3``. Default `keep` value is
'first' so Nauru and Tuvalu will be kept.
>>> s.nsmallest(3)
Monserat 5200
Nauru 11300
Tuvalu 11300
dtype: int64
The `n` smallest elements where ``n=3`` and keeping the last
duplicates. Anguilla and Tuvalu will be kept since they are the last
with value 11300 based on the index order.
>>> s.nsmallest(3, keep='last')
Monserat 5200
Anguilla 11300
Tuvalu 11300
dtype: int64
The `n` smallest elements where ``n=3`` with all duplicates kept. Note
that the returned Series has four elements due to the three duplicates.
>>> s.nsmallest(3, keep='all')
Monserat 5200
Nauru 11300
Tuvalu 11300
Anguilla 11300
dtype: int64
"""
return algorithms.SelectNSeries(self, n=n, keep=keep).nsmallest()
def swaplevel(self, i=-2, j=-1, copy=True):
"""
Swap levels i and j in a :class:`MultiIndex`.
Default is to swap the two innermost levels of the index.
Parameters
----------
i, j : int, str (can be mixed)
Level of index to be swapped. Can pass level name as string.
copy : bool, default True
Whether to copy underlying data.
Returns
-------
Series
Series with levels swapped in MultiIndex.
"""
new_index = self.index.swaplevel(i, j)
return self._constructor(self._values, index=new_index, copy=copy).__finalize__(
self
)
def reorder_levels(self, order):
"""
Rearrange index levels using input order.
May not drop or duplicate levels.
Parameters
----------
order : list of int representing new level order
(reference level by number or key)
Returns
-------
type of caller (new object)
"""
if not isinstance(self.index, MultiIndex): # pragma: no cover
raise Exception("Can only reorder levels on a hierarchical axis.")
result = self.copy()
result.index = result.index.reorder_levels(order)
return result
def explode(self) -> "Series":
"""
Transform each element of a list-like to a row, replicating the
index values.
.. versionadded:: 0.25.0
Returns
-------
Series
Exploded lists to rows; index will be duplicated for these rows.
See Also
--------
Series.str.split : Split string values on specified separator.
Series.unstack : Unstack, a.k.a. pivot, Series with MultiIndex
to produce DataFrame.
DataFrame.melt : Unpivot a DataFrame from wide format to long format.
DataFrame.explode : Explode a DataFrame from list-like
columns to long format.
Notes
-----
This routine will explode list-likes including lists, tuples,
Series, and np.ndarray. The result dtype of the subset rows will
be object. Scalars will be returned unchanged. Empty list-likes will
result in a np.nan for that row.
Examples
--------
>>> s = pd.Series([[1, 2, 3], 'foo', [], [3, 4]])
>>> s
0 [1, 2, 3]
1 foo
2 []
3 [3, 4]
dtype: object
>>> s.explode()
0 1
0 2
0 3
1 foo
2 NaN
3 3
3 4
dtype: object
"""
if not len(self) or not is_object_dtype(self):
return self.copy()
values, counts = reshape.explode(np.asarray(self.array))
result = Series(values, index=self.index.repeat(counts), name=self.name)
return result
def unstack(self, level=-1, fill_value=None):
"""
Unstack, a.k.a. pivot, Series with MultiIndex to produce DataFrame.
The level involved will automatically get sorted.
Parameters
----------
level : int, str, or list of these, default last level
Level(s) to unstack, can pass level name.
fill_value : scalar value, default None
Value to use when replacing NaN values.
Returns
-------
DataFrame
Unstacked Series.
Examples
--------
>>> s = pd.Series([1, 2, 3, 4],
... index=pd.MultiIndex.from_product([['one', 'two'],
... ['a', 'b']]))
>>> s
one a 1
b 2
two a 3
b 4
dtype: int64
>>> s.unstack(level=-1)
a b
one 1 2
two 3 4
>>> s.unstack(level=0)
one two
a 1 3
b 2 4
"""
from pandas.core.reshape.reshape import unstack
return unstack(self, level, fill_value)
# ----------------------------------------------------------------------
# function application
def map(self, arg, na_action=None):
"""
Map values of Series according to input correspondence.
Used for substituting each value in a Series with another value,
that may be derived from a function, a ``dict`` or
a :class:`Series`.
Parameters
----------
arg : function, dict, or Series
Mapping correspondence.
na_action : {None, 'ignore'}, default None
If 'ignore', propagate NaN values, without passing them to the
mapping correspondence.
Returns
-------
Series
Same index as caller.
See Also
--------
Series.apply : For applying more complex functions on a Series.
DataFrame.apply : Apply a function row-/column-wise.
DataFrame.applymap : Apply a function elementwise on a whole DataFrame.
Notes
-----
When ``arg`` is a dictionary, values in Series that are not in the
dictionary (as keys) are converted to ``NaN``. However, if the
dictionary is a ``dict`` subclass that defines ``__missing__`` (i.e.
provides a method for default values), then this default is used
rather than ``NaN``.
Examples
--------
>>> s = pd.Series(['cat', 'dog', np.nan, 'rabbit'])
>>> s
0 cat
1 dog
2 NaN
3 rabbit
dtype: object
``map`` accepts a ``dict`` or a ``Series``. Values that are not found
in the ``dict`` are converted to ``NaN``, unless the dict has a default
value (e.g. ``defaultdict``):
>>> s.map({'cat': 'kitten', 'dog': 'puppy'})
0 kitten
1 puppy
2 NaN
3 NaN
dtype: object
It also accepts a function:
>>> s.map('I am a {}'.format)
0 I am a cat
1 I am a dog
2 I am a nan
3 I am a rabbit
dtype: object
To avoid applying the function to missing values (and keep them as
``NaN``) ``na_action='ignore'`` can be used:
>>> s.map('I am a {}'.format, na_action='ignore')
0 I am a cat
1 I am a dog
2 NaN
3 I am a rabbit
dtype: object
"""
new_values = super()._map_values(arg, na_action=na_action)
return self._constructor(new_values, index=self.index).__finalize__(self)
def _gotitem(self, key, ndim, subset=None):
"""
Sub-classes to define. Return a sliced object.
Parameters
----------
key : string / list of selections
ndim : 1,2
requested ndim of result
subset : object, default None
subset to act on
"""
return self
_agg_see_also_doc = dedent(
"""
See Also
--------
Series.apply : Invoke function on a Series.
Series.transform : Transform function producing a Series with like indexes.
"""
)
_agg_examples_doc = dedent(
"""
Examples
--------
>>> s = pd.Series([1, 2, 3, 4])
>>> s
0 1
1 2
2 3
3 4
dtype: int64
>>> s.agg('min')
1
>>> s.agg(['min', 'max'])
min 1
max 4
dtype: int64
"""
)
@Substitution(
see_also=_agg_see_also_doc,
examples=_agg_examples_doc,
versionadded="\n.. versionadded:: 0.20.0\n",
**_shared_doc_kwargs
)
@Appender(generic._shared_docs["aggregate"])
def aggregate(self, func, axis=0, *args, **kwargs):
# Validate the axis parameter
self._get_axis_number(axis)
result, how = self._aggregate(func, *args, **kwargs)
if result is None:
# we can be called from an inner function which
# passes this meta-data
kwargs.pop("_axis", None)
kwargs.pop("_level", None)
# try a regular apply, this evaluates lambdas
# row-by-row; however if the lambda is expected a Series
# expression, e.g.: lambda x: x-x.quantile(0.25)
# this will fail, so we can try a vectorized evaluation
# we cannot FIRST try the vectorized evaluation, because
# then .agg and .apply would have different semantics if the
# operation is actually defined on the Series, e.g. str
try:
result = self.apply(func, *args, **kwargs)
except (ValueError, AttributeError, TypeError):
result = func(self, *args, **kwargs)
return result
agg = aggregate
@Appender(generic._shared_docs["transform"] % _shared_doc_kwargs)
def transform(self, func, axis=0, *args, **kwargs):
# Validate the axis parameter
self._get_axis_number(axis)
return super().transform(func, *args, **kwargs)
def apply(self, func, convert_dtype=True, args=(), **kwds):
"""
Invoke function on values of Series.
Can be ufunc (a NumPy function that applies to the entire Series)
or a Python function that only works on single values.
Parameters
----------
func : function
Python function or NumPy ufunc to apply.
convert_dtype : bool, default True
Try to find better dtype for elementwise function results. If
False, leave as dtype=object.
args : tuple
Positional arguments passed to func after the series value.
**kwds
Additional keyword arguments passed to func.
Returns
-------
Series or DataFrame
If func returns a Series object the result will be a DataFrame.
See Also
--------
Series.map: For element-wise operations.
Series.agg: Only perform aggregating type operations.
Series.transform: Only perform transforming type operations.
Examples
--------
Create a series with typical summer temperatures for each city.
>>> s = pd.Series([20, 21, 12],
... index=['London', 'New York', 'Helsinki'])
>>> s
London 20
New York 21
Helsinki 12
dtype: int64
Square the values by defining a function and passing it as an
argument to ``apply()``.
>>> def square(x):
... return x ** 2
>>> s.apply(square)
London 400
New York 441
Helsinki 144
dtype: int64
Square the values by passing an anonymous function as an
argument to ``apply()``.
>>> s.apply(lambda x: x ** 2)
London 400
New York 441
Helsinki 144
dtype: int64
Define a custom function that needs additional positional
arguments and pass these additional arguments using the
``args`` keyword.
>>> def subtract_custom_value(x, custom_value):
... return x - custom_value
>>> s.apply(subtract_custom_value, args=(5,))
London 15
New York 16
Helsinki 7
dtype: int64
Define a custom function that takes keyword arguments
and pass these arguments to ``apply``.
>>> def add_custom_values(x, **kwargs):
... for month in kwargs:
... x += kwargs[month]
... return x
>>> s.apply(add_custom_values, june=30, july=20, august=25)
London 95
New York 96
Helsinki 87
dtype: int64
Use a function from the Numpy library.
>>> s.apply(np.log)
London 2.995732
New York 3.044522
Helsinki 2.484907
dtype: float64
"""
if len(self) == 0:
return self._constructor(dtype=self.dtype, index=self.index).__finalize__(
self
)
# dispatch to agg
if isinstance(func, (list, dict)):
return self.aggregate(func, *args, **kwds)
# if we are a string, try to dispatch
if isinstance(func, str):
return self._try_aggregate_string_function(func, *args, **kwds)
# handle ufuncs and lambdas
if kwds or args and not isinstance(func, np.ufunc):
def f(x):
return func(x, *args, **kwds)
else:
f = func
with np.errstate(all="ignore"):
if isinstance(f, np.ufunc):
return f(self)
# row-wise access
if is_extension_type(self.dtype):
mapped = self._values.map(f)
else:
values = self.astype(object).values
mapped = lib.map_infer(values, f, convert=convert_dtype)
if len(mapped) and isinstance(mapped[0], Series):
# GH 25959 use pd.array instead of tolist
# so extension arrays can be used
return self._constructor_expanddim(pd.array(mapped), index=self.index)
else:
return self._constructor(mapped, index=self.index).__finalize__(self)
def _reduce(
self, op, name, axis=0, skipna=True, numeric_only=None, filter_type=None, **kwds
):
"""
Perform a reduction operation.
If we have an ndarray as a value, then simply perform the operation,
otherwise delegate to the object.
"""
delegate = self._values
if axis is not None:
self._get_axis_number(axis)
if isinstance(delegate, Categorical):
# TODO deprecate numeric_only argument for Categorical and use
# skipna as well, see GH25303
return delegate._reduce(name, numeric_only=numeric_only, **kwds)
elif isinstance(delegate, ExtensionArray):
# dispatch to ExtensionArray interface
return delegate._reduce(name, skipna=skipna, **kwds)
elif is_datetime64_dtype(delegate):
# use DatetimeIndex implementation to handle skipna correctly
delegate = DatetimeIndex(delegate)
elif is_timedelta64_dtype(delegate) and hasattr(TimedeltaIndex, name):
# use TimedeltaIndex to handle skipna correctly
# TODO: remove hasattr check after TimedeltaIndex has `std` method
delegate = TimedeltaIndex(delegate)
# dispatch to numpy arrays
elif isinstance(delegate, np.ndarray):
if numeric_only:
raise NotImplementedError(
"Series.{0} does not implement numeric_only.".format(name)
)
with np.errstate(all="ignore"):
return op(delegate, skipna=skipna, **kwds)
# TODO(EA) dispatch to Index
# remove once all internals extension types are
# moved to ExtensionArrays
return delegate._reduce(
op=op,
name=name,
axis=axis,
skipna=skipna,
numeric_only=numeric_only,
filter_type=filter_type,
**kwds
)
def _reindex_indexer(self, new_index, indexer, copy):
if indexer is None:
if copy:
return self.copy()
return self
new_values = algorithms.take_1d(
self._values, indexer, allow_fill=True, fill_value=None
)
return self._constructor(new_values, index=new_index)
def _needs_reindex_multi(self, axes, method, level):
"""
Check if we do need a multi reindex; this is for compat with
higher dims.
"""
return False
@Appender(generic._shared_docs["align"] % _shared_doc_kwargs)
def align(
self,
other,
join="outer",
axis=None,
level=None,
copy=True,
fill_value=None,
method=None,
limit=None,
fill_axis=0,
broadcast_axis=None,
):
return super().align(
other,
join=join,
axis=axis,
level=level,
copy=copy,
fill_value=fill_value,
method=method,
limit=limit,
fill_axis=fill_axis,
broadcast_axis=broadcast_axis,
)
def rename(self, index=None, **kwargs):
"""
Alter Series index labels or name.
Function / dict values must be unique (1-to-1). Labels not contained in
a dict / Series will be left as-is. Extra labels listed don't throw an
error.
Alternatively, change ``Series.name`` with a scalar value.
See the :ref:`user guide <basics.rename>` for more.
Parameters
----------
index : scalar, hashable sequence, dict-like or function, optional
dict-like or functions are transformations to apply to
the index.
Scalar or hashable sequence-like will alter the ``Series.name``
attribute.
copy : bool, default True
Whether to copy underlying data.
inplace : bool, default False
Whether to return a new Series. If True then value of copy is
ignored.
level : int or level name, default None
In case of a MultiIndex, only rename labels in the specified
level.
Returns
-------
Series
Series with index labels or name altered.
See Also
--------
Series.rename_axis : Set the name of the axis.
Examples
--------
>>> s = pd.Series([1, 2, 3])
>>> s
0 1
1 2
2 3
dtype: int64
>>> s.rename("my_name") # scalar, changes Series.name
0 1
1 2
2 3
Name: my_name, dtype: int64
>>> s.rename(lambda x: x ** 2) # function, changes labels
0 1
1 2
4 3
dtype: int64
>>> s.rename({1: 3, 2: 5}) # mapping, changes labels
0 1
3 2
5 3
dtype: int64
"""
kwargs["inplace"] = validate_bool_kwarg(kwargs.get("inplace", False), "inplace")
if callable(index) or is_dict_like(index):
return super().rename(index=index, **kwargs)
else:
return self._set_name(index, inplace=kwargs.get("inplace"))
@Substitution(**_shared_doc_kwargs)
@Appender(generic.NDFrame.reindex.__doc__)
def reindex(self, index=None, **kwargs):
return super().reindex(index=index, **kwargs)
def drop(
self,
labels=None,
axis=0,
index=None,
columns=None,
level=None,
inplace=False,
errors="raise",
):
"""
Return Series with specified index labels removed.
Remove elements of a Series based on specifying the index labels.
When using a multi-index, labels on different levels can be removed
by specifying the level.
Parameters
----------
labels : single label or list-like
Index labels to drop.
axis : 0, default 0
Redundant for application on Series.
index, columns : None
Redundant for application on Series, but index can be used instead
of labels.
.. versionadded:: 0.21.0
level : int or level name, optional
For MultiIndex, level for which the labels will be removed.
inplace : bool, default False
If True, do operation inplace and return None.
errors : {'ignore', 'raise'}, default 'raise'
If 'ignore', suppress error and only existing labels are dropped.
Returns
-------
Series
Series with specified index labels removed.
Raises
------
KeyError
If none of the labels are found in the index.
See Also
--------
Series.reindex : Return only specified index labels of Series.
Series.dropna : Return series without null values.
Series.drop_duplicates : Return Series with duplicate values removed.
DataFrame.drop : Drop specified labels from rows or columns.
Examples
--------
>>> s = pd.Series(data=np.arange(3), index=['A', 'B', 'C'])
>>> s
A 0
B 1
C 2
dtype: int64
Drop labels B en C
>>> s.drop(labels=['B', 'C'])
A 0
dtype: int64
Drop 2nd level label in MultiIndex Series
>>> midx = pd.MultiIndex(levels=[['lama', 'cow', 'falcon'],
... ['speed', 'weight', 'length']],
... codes=[[0, 0, 0, 1, 1, 1, 2, 2, 2],
... [0, 1, 2, 0, 1, 2, 0, 1, 2]])
>>> s = pd.Series([45, 200, 1.2, 30, 250, 1.5, 320, 1, 0.3],
... index=midx)
>>> s
lama speed 45.0
weight 200.0
length 1.2
cow speed 30.0
weight 250.0
length 1.5
falcon speed 320.0
weight 1.0
length 0.3
dtype: float64
>>> s.drop(labels='weight', level=1)
lama speed 45.0
length 1.2
cow speed 30.0
length 1.5
falcon speed 320.0
length 0.3
dtype: float64
"""
return super().drop(
labels=labels,
axis=axis,
index=index,
columns=columns,
level=level,
inplace=inplace,
errors=errors,
)
@Substitution(**_shared_doc_kwargs)
@Appender(generic.NDFrame.fillna.__doc__)
def fillna(
self,
value=None,
method=None,
axis=None,
inplace=False,
limit=None,
downcast=None,
**kwargs
):
return super().fillna(
value=value,
method=method,
axis=axis,
inplace=inplace,
limit=limit,
downcast=downcast,
**kwargs
)
@Appender(generic._shared_docs["replace"] % _shared_doc_kwargs)
def replace(
self,
to_replace=None,
value=None,
inplace=False,
limit=None,
regex=False,
method="pad",
):
return super().replace(
to_replace=to_replace,
value=value,
inplace=inplace,
limit=limit,
regex=regex,
method=method,
)
@Appender(generic._shared_docs["shift"] % _shared_doc_kwargs)
def shift(self, periods=1, freq=None, axis=0, fill_value=None):
return super().shift(
periods=periods, freq=freq, axis=axis, fill_value=fill_value
)
def memory_usage(self, index=True, deep=False):
"""
Return the memory usage of the Series.
The memory usage can optionally include the contribution of
the index and of elements of `object` dtype.
Parameters
----------
index : bool, default True
Specifies whether to include the memory usage of the Series index.
deep : bool, default False
If True, introspect the data deeply by interrogating
`object` dtypes for system-level memory consumption, and include
it in the returned value.
Returns
-------
int
Bytes of memory consumed.
See Also
--------
numpy.ndarray.nbytes : Total bytes consumed by the elements of the
array.
DataFrame.memory_usage : Bytes consumed by a DataFrame.
Examples
--------
>>> s = pd.Series(range(3))
>>> s.memory_usage()
152
Not including the index gives the size of the rest of the data, which
is necessarily smaller:
>>> s.memory_usage(index=False)
24
The memory footprint of `object` values is ignored by default:
>>> s = pd.Series(["a", "b"])
>>> s.values
array(['a', 'b'], dtype=object)
>>> s.memory_usage()
144
>>> s.memory_usage(deep=True)
260
"""
v = super().memory_usage(deep=deep)
if index:
v += self.index.memory_usage(deep=deep)
return v
def isin(self, values):
"""
Check whether `values` are contained in Series.
Return a boolean Series showing whether each element in the Series
matches an element in the passed sequence of `values` exactly.
Parameters
----------
values : set or list-like
The sequence of values to test. Passing in a single string will
raise a ``TypeError``. Instead, turn a single string into a
list of one element.
Returns
-------
Series
Series of booleans indicating if each element is in values.
Raises
------
TypeError
* If `values` is a string
See Also
--------
DataFrame.isin : Equivalent method on DataFrame.
Examples
--------
>>> s = pd.Series(['lama', 'cow', 'lama', 'beetle', 'lama',
... 'hippo'], name='animal')
>>> s.isin(['cow', 'lama'])
0 True
1 True
2 True
3 False
4 True
5 False
Name: animal, dtype: bool
Passing a single string as ``s.isin('lama')`` will raise an error. Use
a list of one element instead:
>>> s.isin(['lama'])
0 True
1 False
2 True
3 False
4 True
5 False
Name: animal, dtype: bool
"""
result = algorithms.isin(self, values)
return self._constructor(result, index=self.index).__finalize__(self)
def between(self, left, right, inclusive=True):
"""
Return boolean Series equivalent to left <= series <= right.
This function returns a boolean vector containing `True` wherever the
corresponding Series element is between the boundary values `left` and
`right`. NA values are treated as `False`.
Parameters
----------
left : scalar
Left boundary.
right : scalar
Right boundary.
inclusive : bool, default True
Include boundaries.
Returns
-------
Series
Series representing whether each element is between left and
right (inclusive).
See Also
--------
Series.gt : Greater than of series and other.
Series.lt : Less than of series and other.
Notes
-----
This function is equivalent to ``(left <= ser) & (ser <= right)``
Examples
--------
>>> s = pd.Series([2, 0, 4, 8, np.nan])
Boundary values are included by default:
>>> s.between(1, 4)
0 True
1 False
2 True
3 False
4 False
dtype: bool
With `inclusive` set to ``False`` boundary values are excluded:
>>> s.between(1, 4, inclusive=False)
0 True
1 False
2 False
3 False
4 False
dtype: bool
`left` and `right` can be any scalar value:
>>> s = pd.Series(['Alice', 'Bob', 'Carol', 'Eve'])
>>> s.between('Anna', 'Daniel')
0 False
1 True
2 True
3 False
dtype: bool
"""
if inclusive:
lmask = self >= left
rmask = self <= right
else:
lmask = self > left
rmask = self < right
return lmask & rmask
@Appender(generic.NDFrame.to_csv.__doc__)
def to_csv(self, *args, **kwargs):
names = [
"path_or_buf",
"sep",
"na_rep",
"float_format",
"columns",
"header",
"index",
"index_label",
"mode",
"encoding",
"compression",
"quoting",
"quotechar",
"line_terminator",
"chunksize",
"date_format",
"doublequote",
"escapechar",
"decimal",
]
old_names = [
"path_or_buf",
"index",
"sep",
"na_rep",
"float_format",
"header",
"index_label",
"mode",
"encoding",
"compression",
"date_format",
"decimal",
]
if "path" in kwargs:
warnings.warn(
"The signature of `Series.to_csv` was aligned "
"to that of `DataFrame.to_csv`, and argument "
"'path' will be renamed to 'path_or_buf'.",
FutureWarning,
stacklevel=2,
)
kwargs["path_or_buf"] = kwargs.pop("path")
if len(args) > 1:
# Either "index" (old signature) or "sep" (new signature) is being
# passed as second argument (while the first is the same)
maybe_sep = args[1]
if not (is_string_like(maybe_sep) and len(maybe_sep) == 1):
# old signature
warnings.warn(
"The signature of `Series.to_csv` was aligned "
"to that of `DataFrame.to_csv`. Note that the "
"order of arguments changed, and the new one "
"has 'sep' in first place, for which \"{}\" is "
"not a valid value. The old order will cease to "
"be supported in a future version. Please refer "
"to the documentation for `DataFrame.to_csv` "
"when updating your function "
"calls.".format(maybe_sep),
FutureWarning,
stacklevel=2,
)
names = old_names
pos_args = dict(zip(names[: len(args)], args))
for key in pos_args:
if key in kwargs:
raise ValueError(
"Argument given by name ('{}') and position "
"({})".format(key, names.index(key))
)
kwargs[key] = pos_args[key]
if kwargs.get("header", None) is None:
warnings.warn(
"The signature of `Series.to_csv` was aligned "
"to that of `DataFrame.to_csv`, and argument "
"'header' will change its default value from False "
"to True: please pass an explicit value to suppress "
"this warning.",
FutureWarning,
stacklevel=2,
)
kwargs["header"] = False # Backwards compatibility.
return self.to_frame().to_csv(**kwargs)
@Appender(generic._shared_docs["isna"] % _shared_doc_kwargs)
def isna(self):
return super().isna()
@Appender(generic._shared_docs["isna"] % _shared_doc_kwargs)
def isnull(self):
return super().isnull()
@Appender(generic._shared_docs["notna"] % _shared_doc_kwargs)
def notna(self):
return super().notna()
@Appender(generic._shared_docs["notna"] % _shared_doc_kwargs)
def notnull(self):
return super().notnull()
def dropna(self, axis=0, inplace=False, **kwargs):
"""
Return a new Series with missing values removed.
See the :ref:`User Guide <missing_data>` for more on which values are
considered missing, and how to work with missing data.
Parameters
----------
axis : {0 or 'index'}, default 0
There is only one axis to drop values from.
inplace : bool, default False
If True, do operation inplace and return None.
**kwargs
Not in use.
Returns
-------
Series
Series with NA entries dropped from it.
See Also
--------
Series.isna: Indicate missing values.
Series.notna : Indicate existing (non-missing) values.
Series.fillna : Replace missing values.
DataFrame.dropna : Drop rows or columns which contain NA values.
Index.dropna : Drop missing indices.
Examples
--------
>>> ser = pd.Series([1., 2., np.nan])
>>> ser
0 1.0
1 2.0
2 NaN
dtype: float64
Drop NA values from a Series.
>>> ser.dropna()
0 1.0
1 2.0
dtype: float64
Keep the Series with valid entries in the same variable.
>>> ser.dropna(inplace=True)
>>> ser
0 1.0
1 2.0
dtype: float64
Empty strings are not considered NA values. ``None`` is considered an
NA value.
>>> ser = pd.Series([np.NaN, 2, pd.NaT, '', None, 'I stay'])
>>> ser
0 NaN
1 2
2 NaT
3
4 None
5 I stay
dtype: object
>>> ser.dropna()
1 2
3
5 I stay
dtype: object
"""
inplace = validate_bool_kwarg(inplace, "inplace")
kwargs.pop("how", None)
if kwargs:
raise TypeError(
"dropna() got an unexpected keyword "
'argument "{0}"'.format(list(kwargs.keys())[0])
)
# Validate the axis parameter
self._get_axis_number(axis or 0)
if self._can_hold_na:
result = remove_na_arraylike(self)
if inplace:
self._update_inplace(result)
else:
return result
else:
if inplace:
# do nothing
pass
else:
return self.copy()
def valid(self, inplace=False, **kwargs):
"""
Return Series without null values.
.. deprecated:: 0.23.0
Use :meth:`Series.dropna` instead.
Returns
-------
Series
Series without null values.
"""
warnings.warn(
"Method .valid will be removed in a future version. "
"Use .dropna instead.",
FutureWarning,
stacklevel=2,
)
return self.dropna(inplace=inplace, **kwargs)
# ----------------------------------------------------------------------
# Time series-oriented methods
def to_timestamp(self, freq=None, how="start", copy=True):
"""
Cast to DatetimeIndex of Timestamps, at *beginning* of period.
Parameters
----------
freq : str, default frequency of PeriodIndex
Desired frequency.
how : {'s', 'e', 'start', 'end'}
Convention for converting period to timestamp; start of period
vs. end.
copy : bool, default True
Whether or not to return a copy.
Returns
-------
Series with DatetimeIndex
"""
new_values = self._values
if copy:
new_values = new_values.copy()
new_index = self.index.to_timestamp(freq=freq, how=how)
return self._constructor(new_values, index=new_index).__finalize__(self)
def to_period(self, freq=None, copy=True):
"""
Convert Series from DatetimeIndex to PeriodIndex with desired
frequency (inferred from index if not passed).
Parameters
----------
freq : str, default None
Frequency associated with the PeriodIndex.
copy : bool, default True
Whether or not to return a copy.
Returns
-------
Series
Series with index converted to PeriodIndex.
"""
new_values = self._values
if copy:
new_values = new_values.copy()
new_index = self.index.to_period(freq=freq)
return self._constructor(new_values, index=new_index).__finalize__(self)
# ----------------------------------------------------------------------
# Accessor Methods
# ----------------------------------------------------------------------
str = CachedAccessor("str", StringMethods)
dt = CachedAccessor("dt", CombinedDatetimelikeProperties)
cat = CachedAccessor("cat", CategoricalAccessor)
plot = CachedAccessor("plot", pandas.plotting.PlotAccessor)
sparse = CachedAccessor("sparse", SparseAccessor)
# ----------------------------------------------------------------------
# Add plotting methods to Series
hist = pandas.plotting.hist_series
Series._setup_axes(
["index"],
info_axis=0,
stat_axis=0,
aliases={"rows": 0},
docs={"index": "The index (axis labels) of the Series."},
)
Series._add_numeric_operations()
Series._add_series_only_operations()
Series._add_series_or_dataframe_operations()
# Add arithmetic!
ops.add_flex_arithmetic_methods(Series)
ops.add_special_arithmetic_methods(Series)
"""
Data structure for 1-dimensional cross-sectional and time series data
"""
from collections import OrderedDict
from io import StringIO
from shutil import get_terminal_size
from textwrap import dedent
from typing import Any, Callable
import warnings
import numpy as np
from pandas._config import get_option
from pandas._libs import index as libindex, lib, reshape, tslibs
from pandas.compat import PY36
from pandas.compat.numpy import function as nv
from pandas.util._decorators import Appender, Substitution, deprecate
from pandas.util._validators import validate_bool_kwarg
from pandas.core.dtypes.common import (
_is_unorderable_exception,
ensure_platform_int,
is_bool,
is_categorical,
is_categorical_dtype,
is_datetime64_dtype,
is_datetimelike,
is_dict_like,
is_extension_array_dtype,
is_extension_type,
is_hashable,
is_integer,
is_iterator,
is_list_like,
is_object_dtype,
is_scalar,
is_string_like,
is_timedelta64_dtype,
)
from pandas.core.dtypes.generic import (
ABCDataFrame,
ABCDatetimeArray,
ABCDatetimeIndex,
ABCSeries,
ABCSparseArray,
ABCSparseSeries,
)
from pandas.core.dtypes.missing import (
isna,
na_value_for_dtype,
notna,
remove_na_arraylike,
)
import pandas as pd
from pandas.core import algorithms, base, generic, nanops, ops
from pandas.core.accessor import CachedAccessor
from pandas.core.arrays import ExtensionArray, SparseArray
from pandas.core.arrays.categorical import Categorical, CategoricalAccessor
from pandas.core.arrays.sparse import SparseAccessor
import pandas.core.common as com
from pandas.core.construction import extract_array, sanitize_array
from pandas.core.index import (
Float64Index,
Index,
InvalidIndexError,
MultiIndex,
ensure_index,
)
from pandas.core.indexers import maybe_convert_indices
from pandas.core.indexes.accessors import CombinedDatetimelikeProperties
import pandas.core.indexes.base as ibase
from pandas.core.indexes.datetimes import DatetimeIndex
from pandas.core.indexes.period import PeriodIndex
from pandas.core.indexes.timedeltas import TimedeltaIndex
from pandas.core.indexing import check_bool_indexer
from pandas.core.internals import SingleBlockManager
from pandas.core.strings import StringMethods
from pandas.core.tools.datetimes import to_datetime
import pandas.io.formats.format as fmt
import pandas.plotting
__all__ = ["Series"]
_shared_doc_kwargs = dict(
axes="index",
klass="Series",
axes_single_arg="{0 or 'index'}",
axis="""axis : {0 or 'index'}
Parameter needed for compatibility with DataFrame.""",
inplace="""inplace : boolean, default False
If True, performs operation inplace and returns None.""",
unique="np.ndarray",
duplicated="Series",
optional_by="",
optional_mapper="",
optional_labels="",
optional_axis="",
versionadded_to_excel="\n .. versionadded:: 0.20.0\n",
)
# see gh-16971
def remove_na(arr):
"""
Remove null values from array like structure.
.. deprecated:: 0.21.0
Use s[s.notnull()] instead.
"""
warnings.warn(
"remove_na is deprecated and is a private function. Do not use.",
FutureWarning,
stacklevel=2,
)
return remove_na_arraylike(arr)
def _coerce_method(converter):
"""
Install the scalar coercion methods.
"""
def wrapper(self):
if len(self) == 1:
return converter(self.iloc[0])
raise TypeError("cannot convert the series to {0}".format(str(converter)))
wrapper.__name__ = "__{name}__".format(name=converter.__name__)
return wrapper
# ----------------------------------------------------------------------
# Series class
class Series(base.IndexOpsMixin, generic.NDFrame):
"""
One-dimensional ndarray with axis labels (including time series).
Labels need not be unique but must be a hashable type. The object
supports both integer- and label-based indexing and provides a host of
methods for performing operations involving the index. Statistical
methods from ndarray have been overridden to automatically exclude
missing data (currently represented as NaN).
Operations between Series (+, -, /, *, **) align values based on their
associated index values-- they need not be the same length. The result
index will be the sorted union of the two indexes.
Parameters
----------
data : array-like, Iterable, dict, or scalar value
Contains data stored in Series.
.. versionchanged:: 0.23.0
If data is a dict, argument order is maintained for Python 3.6
and later.
index : array-like or Index (1d)
Values must be hashable and have the same length as `data`.
Non-unique index values are allowed. Will default to
RangeIndex (0, 1, 2, ..., n) if not provided. If both a dict and index
sequence are used, the index will override the keys found in the
dict.
dtype : str, numpy.dtype, or ExtensionDtype, optional
Data type for the output Series. If not specified, this will be
inferred from `data`.
See the :ref:`user guide <basics.dtypes>` for more usages.
copy : bool, default False
Copy input data.
"""
_metadata = ["name"]
_accessors = {"dt", "cat", "str", "sparse"}
# tolist is not actually deprecated, just suppressed in the __dir__
_deprecations = generic.NDFrame._deprecations | frozenset(
["asobject", "reshape", "valid", "tolist"]
)
# Override cache_readonly bc Series is mutable
hasnans = property(
base.IndexOpsMixin.hasnans.func, doc=base.IndexOpsMixin.hasnans.__doc__
)
_data = None # type: SingleBlockManager
# ----------------------------------------------------------------------
# Constructors
def __init__(
self, data=None, index=None, dtype=None, name=None, copy=False, fastpath=False
):
# we are called internally, so short-circuit
if fastpath:
# data is an ndarray, index is defined
if not isinstance(data, SingleBlockManager):
data = SingleBlockManager(data, index, fastpath=True)
if copy:
data = data.copy()
if index is None:
index = data.index
else:
if index is not None:
index = ensure_index(index)
if data is None:
data = {}
if dtype is not None:
# GH 26336: explicitly handle 'category' to avoid warning
# TODO: Remove after CategoricalDtype defaults to ordered=False
if (
isinstance(dtype, str)
and dtype == "category"
and is_categorical(data)
):
dtype = data.dtype
dtype = self._validate_dtype(dtype)
if isinstance(data, MultiIndex):
raise NotImplementedError(
"initializing a Series from a MultiIndex is not supported"
)
elif isinstance(data, Index):
if name is None:
name = data.name
if dtype is not None:
# astype copies
data = data.astype(dtype)
else:
# need to copy to avoid aliasing issues
data = data._values.copy()
if isinstance(data, ABCDatetimeIndex) and data.tz is not None:
# GH#24096 need copy to be deep for datetime64tz case
# TODO: See if we can avoid these copies
data = data._values.copy(deep=True)
copy = False
elif isinstance(data, np.ndarray):
pass
elif isinstance(data, (ABCSeries, ABCSparseSeries)):
if name is None:
name = data.name
if index is None:
index = data.index
else:
data = data.reindex(index, copy=copy)
data = data._data
elif isinstance(data, dict):
data, index = self._init_dict(data, index, dtype)
dtype = None
copy = False
elif isinstance(data, SingleBlockManager):
if index is None:
index = data.index
elif not data.index.equals(index) or copy:
# GH#19275 SingleBlockManager input should only be called
# internally
raise AssertionError(
"Cannot pass both SingleBlockManager "
"`data` argument and a different "
"`index` argument. `copy` must "
"be False."
)
elif is_extension_array_dtype(data):
pass
elif isinstance(data, (set, frozenset)):
raise TypeError(
"{0!r} type is unordered".format(data.__class__.__name__)
)
elif isinstance(data, ABCSparseArray):
# handle sparse passed here (and force conversion)
data = data.to_dense()
else:
data = com.maybe_iterable_to_list(data)
if index is None:
if not is_list_like(data):
data = [data]
index = ibase.default_index(len(data))
elif is_list_like(data):
# a scalar numpy array is list-like but doesn't
# have a proper length
try:
if len(index) != len(data):
raise ValueError(
"Length of passed values is {val}, "
"index implies {ind}".format(val=len(data), ind=len(index))
)
except TypeError:
pass
# create/copy the manager
if isinstance(data, SingleBlockManager):
if dtype is not None:
data = data.astype(dtype=dtype, errors="ignore", copy=copy)
elif copy:
data = data.copy()
else:
data = sanitize_array(data, index, dtype, copy, raise_cast_failure=True)
data = SingleBlockManager(data, index, fastpath=True)
generic.NDFrame.__init__(self, data, fastpath=True)
self.name = name
self._set_axis(0, index, fastpath=True)
def _init_dict(self, data, index=None, dtype=None):
"""
Derive the "_data" and "index" attributes of a new Series from a
dictionary input.
Parameters
----------
data : dict or dict-like
Data used to populate the new Series
index : Index or index-like, default None
index for the new Series: if None, use dict keys
dtype : dtype, default None
dtype for the new Series: if None, infer from data
Returns
-------
_data : BlockManager for the new Series
index : index for the new Series
"""
# Looking for NaN in dict doesn't work ({np.nan : 1}[float('nan')]
# raises KeyError), so we iterate the entire dict, and align
if data:
keys, values = zip(*data.items())
values = list(values)
elif index is not None:
# fastpath for Series(data=None). Just use broadcasting a scalar
# instead of reindexing.
values = na_value_for_dtype(dtype)
keys = index
else:
keys, values = [], []
# Input is now list-like, so rely on "standard" construction:
s = Series(values, index=keys, dtype=dtype)
# Now we just make sure the order is respected, if any
if data and index is not None:
s = s.reindex(index, copy=False)
elif not PY36 and not isinstance(data, OrderedDict) and data:
# Need the `and data` to avoid sorting Series(None, index=[...])
# since that isn't really dict-like
try:
s = s.sort_index()
except TypeError:
pass
return s._data, s.index
@classmethod
def from_array(
cls, arr, index=None, name=None, dtype=None, copy=False, fastpath=False
):
"""
Construct Series from array.
.. deprecated:: 0.23.0
Use pd.Series(..) constructor instead.
Returns
-------
Series
Constructed Series.
"""
warnings.warn(
"'from_array' is deprecated and will be removed in a "
"future version. Please use the pd.Series(..) "
"constructor instead.",
FutureWarning,
stacklevel=2,
)
if isinstance(arr, ABCSparseArray):
from pandas.core.sparse.series import SparseSeries
cls = SparseSeries
return cls(
arr, index=index, name=name, dtype=dtype, copy=copy, fastpath=fastpath
)
# ----------------------------------------------------------------------
@property
def _constructor(self):
return Series
@property
def _constructor_expanddim(self):
from pandas.core.frame import DataFrame
return DataFrame
# types
@property
def _can_hold_na(self):
return self._data._can_hold_na
_index = None
def _set_axis(self, axis, labels, fastpath=False):
"""
Override generic, we want to set the _typ here.
"""
if not fastpath:
labels = ensure_index(labels)
is_all_dates = labels.is_all_dates
if is_all_dates:
if not isinstance(labels, (DatetimeIndex, PeriodIndex, TimedeltaIndex)):
try:
labels = DatetimeIndex(labels)
# need to set here because we changed the index
if fastpath:
self._data.set_axis(axis, labels)
except (tslibs.OutOfBoundsDatetime, ValueError):
# labels may exceeds datetime bounds,
# or not be a DatetimeIndex
pass
self._set_subtyp(is_all_dates)
object.__setattr__(self, "_index", labels)
if not fastpath:
self._data.set_axis(axis, labels)
def _set_subtyp(self, is_all_dates):
if is_all_dates:
object.__setattr__(self, "_subtyp", "time_series")
else:
object.__setattr__(self, "_subtyp", "series")
def _update_inplace(self, result, **kwargs):
# we want to call the generic version and not the IndexOpsMixin
return generic.NDFrame._update_inplace(self, result, **kwargs)
@property
def name(self):
"""
Return name of the Series.
"""
return self._name
@name.setter
def name(self, value):
if value is not None and not is_hashable(value):
raise TypeError("Series.name must be a hashable type")
object.__setattr__(self, "_name", value)
# ndarray compatibility
@property
def dtype(self):
"""
Return the dtype object of the underlying data.
"""
return self._data.dtype
@property
def dtypes(self):
"""
Return the dtype object of the underlying data.
"""
return self._data.dtype
@property
def ftype(self):
"""
Return if the data is sparse|dense.
.. deprecated:: 0.25.0
Use :func:`dtype` instead.
"""
warnings.warn(
"Series.ftype is deprecated and will "
"be removed in a future version. "
"Use Series.dtype instead.",
FutureWarning,
stacklevel=2,
)
return self._data.ftype
@property
def ftypes(self):
"""
Return if the data is sparse|dense.
.. deprecated:: 0.25.0
Use :func:`dtypes` instead.
"""
warnings.warn(
"Series.ftypes is deprecated and will "
"be removed in a future version. "
"Use Series.dtype instead.",
FutureWarning,
stacklevel=2,
)
return self._data.ftype
@property
def values(self):
"""
Return Series as ndarray or ndarray-like depending on the dtype.
.. warning::
We recommend using :attr:`Series.array` or
:meth:`Series.to_numpy`, depending on whether you need
a reference to the underlying data or a NumPy array.
Returns
-------
numpy.ndarray or ndarray-like
See Also
--------
Series.array : Reference to the underlying data.
Series.to_numpy : A NumPy array representing the underlying data.
Examples
--------
>>> pd.Series([1, 2, 3]).values
array([1, 2, 3])
>>> pd.Series(list('aabc')).values
array(['a', 'a', 'b', 'c'], dtype=object)
>>> pd.Series(list('aabc')).astype('category').values
[a, a, b, c]
Categories (3, object): [a, b, c]
Timezone aware datetime data is converted to UTC:
>>> pd.Series(pd.date_range('20130101', periods=3,
... tz='US/Eastern')).values
array(['2013-01-01T05:00:00.000000000',
'2013-01-02T05:00:00.000000000',
'2013-01-03T05:00:00.000000000'], dtype='datetime64[ns]')
"""
return self._data.external_values()
@property
def _values(self):
"""
Return the internal repr of this data.
"""
return self._data.internal_values()
def get_values(self):
"""
Same as values (but handles sparseness conversions); is a view.
.. deprecated:: 0.25.0
Use :meth:`Series.to_numpy` or :attr:`Series.array` instead.
Returns
-------
numpy.ndarray
Data of the Series.
"""
warnings.warn(
"The 'get_values' method is deprecated and will be removed in a "
"future version. Use '.to_numpy()' or '.array' instead.",
FutureWarning,
stacklevel=2,
)
return self._internal_get_values()
def _internal_get_values(self):
return self._data.get_values()
@property
def asobject(self):
"""
Return object Series which contains boxed values.
.. deprecated:: 0.23.0
Use ``astype(object)`` instead.
*this is an internal non-public method*
"""
warnings.warn(
"'asobject' is deprecated. Use 'astype(object)' instead",
FutureWarning,
stacklevel=2,
)
return self.astype(object).values
# ops
def ravel(self, order="C"):
"""
Return the flattened underlying data as an ndarray.
Returns
-------
numpy.ndarray or ndarray-like
Flattened data of the Series.
See Also
--------
numpy.ndarray.ravel
"""
return self._values.ravel(order=order)
def compress(self, condition, *args, **kwargs):
"""
Return selected slices of an array along given axis as a Series.
.. deprecated:: 0.24.0
Returns
-------
Series
Series without the slices for which condition is false.
See Also
--------
numpy.ndarray.compress
"""
msg = (
"Series.compress(condition) is deprecated. "
"Use 'Series[condition]' or "
"'np.asarray(series).compress(condition)' instead."
)
warnings.warn(msg, FutureWarning, stacklevel=2)
nv.validate_compress(args, kwargs)
return self[condition]
def nonzero(self):
"""
Return the *integer* indices of the elements that are non-zero.
.. deprecated:: 0.24.0
Please use .to_numpy().nonzero() as a replacement.
This method is equivalent to calling `numpy.nonzero` on the
series data. For compatibility with NumPy, the return value is
the same (a tuple with an array of indices for each dimension),
but it will always be a one-item tuple because series only have
one dimension.
Returns
-------
numpy.ndarray
Indices of elements that are non-zero.
See Also
--------
numpy.nonzero
Examples
--------
>>> s = pd.Series([0, 3, 0, 4])
>>> s.nonzero()
(array([1, 3]),)
>>> s.iloc[s.nonzero()[0]]
1 3
3 4
dtype: int64
# same return although index of s is different
>>> s = pd.Series([0, 3, 0, 4], index=['a', 'b', 'c', 'd'])
>>> s.nonzero()
(array([1, 3]),)
>>> s.iloc[s.nonzero()[0]]
b 3
d 4
dtype: int64
"""
msg = (
"Series.nonzero() is deprecated "
"and will be removed in a future version."
"Use Series.to_numpy().nonzero() instead"
)
warnings.warn(msg, FutureWarning, stacklevel=2)
return self._values.nonzero()
def put(self, *args, **kwargs):
"""
Apply the `put` method to its `values` attribute if it has one.
.. deprecated:: 0.25.0
See Also
--------
numpy.ndarray.put
"""
warnings.warn(
"`put` has been deprecated and will be removed in a future version.",
FutureWarning,
stacklevel=2,
)
self._values.put(*args, **kwargs)
def __len__(self):
"""
Return the length of the Series.
"""
return len(self._data)
def view(self, dtype=None):
"""
Create a new view of the Series.
This function will return a new Series with a view of the same
underlying values in memory, optionally reinterpreted with a new data
type. The new data type must preserve the same size in bytes as to not
cause index misalignment.
Parameters
----------
dtype : data type
Data type object or one of their string representations.
Returns
-------
Series
A new Series object as a view of the same data in memory.
See Also
--------
numpy.ndarray.view : Equivalent numpy function to create a new view of
the same data in memory.
Notes
-----
Series are instantiated with ``dtype=float64`` by default. While
``numpy.ndarray.view()`` will return a view with the same data type as
the original array, ``Series.view()`` (without specified dtype)
will try using ``float64`` and may fail if the original data type size
in bytes is not the same.
Examples
--------
>>> s = pd.Series([-2, -1, 0, 1, 2], dtype='int8')
>>> s
0 -2
1 -1
2 0
3 1
4 2
dtype: int8
The 8 bit signed integer representation of `-1` is `0b11111111`, but
the same bytes represent 255 if read as an 8 bit unsigned integer:
>>> us = s.view('uint8')
>>> us
0 254
1 255
2 0
3 1
4 2
dtype: uint8
The views share the same underlying values:
>>> us[0] = 128
>>> s
0 -128
1 -1
2 0
3 1
4 2
dtype: int8
"""
return self._constructor(
self._values.view(dtype), index=self.index
).__finalize__(self)
# ----------------------------------------------------------------------
# NDArray Compat
_HANDLED_TYPES = (Index, ExtensionArray, np.ndarray)
def __array_ufunc__(
self, ufunc: Callable, method: str, *inputs: Any, **kwargs: Any
):
# TODO: handle DataFrame
cls = type(self)
# for binary ops, use our custom dunder methods
result = ops.maybe_dispatch_ufunc_to_dunder_op(
self, ufunc, method, *inputs, **kwargs
)
if result is not NotImplemented:
return result
# Determine if we should defer.
no_defer = (np.ndarray.__array_ufunc__, cls.__array_ufunc__)
for item in inputs:
higher_priority = (
hasattr(item, "__array_priority__")
and item.__array_priority__ > self.__array_priority__
)
has_array_ufunc = (
hasattr(item, "__array_ufunc__")
and type(item).__array_ufunc__ not in no_defer
and not isinstance(item, self._HANDLED_TYPES)
)
if higher_priority or has_array_ufunc:
return NotImplemented
# align all the inputs.
names = [getattr(x, "name") for x in inputs if hasattr(x, "name")]
types = tuple(type(x) for x in inputs)
# TODO: dataframe
alignable = [x for x, t in zip(inputs, types) if issubclass(t, Series)]
if len(alignable) > 1:
# This triggers alignment.
# At the moment, there aren't any ufuncs with more than two inputs
# so this ends up just being x1.index | x2.index, but we write
# it to handle *args.
index = alignable[0].index
for s in alignable[1:]:
index |= s.index
inputs = tuple(
x.reindex(index) if issubclass(t, Series) else x
for x, t in zip(inputs, types)
)
else:
index = self.index
inputs = tuple(extract_array(x, extract_numpy=True) for x in inputs)
result = getattr(ufunc, method)(*inputs, **kwargs)
if len(set(names)) == 1:
# we require names to be hashable, right?
name = names[0] # type: Any
else:
name = None
def construct_return(result):
if lib.is_scalar(result):
return result
elif result.ndim > 1:
# e.g. np.subtract.outer
if method == "outer":
msg = (
"outer method for ufunc {} is not implemented on "
"pandas objects. Returning an ndarray, but in the "
"future this will raise a 'NotImplementedError'. "
"Consider explicitly converting the Series "
"to an array with '.array' first."
)
warnings.warn(msg.format(ufunc), FutureWarning, stacklevel=3)
return result
return self._constructor(result, index=index, name=name, copy=False)
if type(result) is tuple:
# multiple return values
return tuple(construct_return(x) for x in result)
elif method == "at":
# no return value
return None
else:
return construct_return(result)
def __array__(self, dtype=None):
"""
Return the values as a NumPy array.
Users should not call this directly. Rather, it is invoked by
:func:`numpy.array` and :func:`numpy.asarray`.
Parameters
----------
dtype : str or numpy.dtype, optional
The dtype to use for the resulting NumPy array. By default,
the dtype is inferred from the data.
Returns
-------
numpy.ndarray
The values in the series converted to a :class:`numpy.ndarary`
with the specified `dtype`.
See Also
--------
array : Create a new array from data.
Series.array : Zero-copy view to the array backing the Series.
Series.to_numpy : Series method for similar behavior.
Examples
--------
>>> ser = pd.Series([1, 2, 3])
>>> np.asarray(ser)
array([1, 2, 3])
For timezone-aware data, the timezones may be retained with
``dtype='object'``
>>> tzser = pd.Series(pd.date_range('2000', periods=2, tz="CET"))
>>> np.asarray(tzser, dtype="object")
array([Timestamp('2000-01-01 00:00:00+0100', tz='CET', freq='D'),
Timestamp('2000-01-02 00:00:00+0100', tz='CET', freq='D')],
dtype=object)
Or the values may be localized to UTC and the tzinfo discared with
``dtype='datetime64[ns]'``
>>> np.asarray(tzser, dtype="datetime64[ns]") # doctest: +ELLIPSIS
array(['1999-12-31T23:00:00.000000000', ...],
dtype='datetime64[ns]')
"""
if (
dtype is None
and isinstance(self.array, ABCDatetimeArray)
and getattr(self.dtype, "tz", None)
):
msg = (
"Converting timezone-aware DatetimeArray to timezone-naive "
"ndarray with 'datetime64[ns]' dtype. In the future, this "
"will return an ndarray with 'object' dtype where each "
"element is a 'pandas.Timestamp' with the correct 'tz'.\n\t"
"To accept the future behavior, pass 'dtype=object'.\n\t"
"To keep the old behavior, pass 'dtype=\"datetime64[ns]\"'."
)
warnings.warn(msg, FutureWarning, stacklevel=3)
dtype = "M8[ns]"
return np.asarray(self.array, dtype)
# ----------------------------------------------------------------------
# Unary Methods
@property
def real(self):
"""
Return the real value of vector.
.. deprecated:: 0.25.0
"""
warnings.warn(
"`real` is deprecated and will be removed in a future version. "
"To eliminate this warning for a Series `ser`, use "
"`np.real(ser.to_numpy())` or `ser.to_numpy().real`.",
FutureWarning,
stacklevel=2,
)
return self.values.real
@real.setter
def real(self, v):
self.values.real = v
@property
def imag(self):
"""
Return imag value of vector.
.. deprecated:: 0.25.0
"""
warnings.warn(
"`imag` is deprecated and will be removed in a future version. "
"To eliminate this warning for a Series `ser`, use "
"`np.imag(ser.to_numpy())` or `ser.to_numpy().imag`.",
FutureWarning,
stacklevel=2,
)
return self.values.imag
@imag.setter
def imag(self, v):
self.values.imag = v
# coercion
__float__ = _coerce_method(float)
__long__ = _coerce_method(int)
__int__ = _coerce_method(int)
# ----------------------------------------------------------------------
def _unpickle_series_compat(self, state):
if isinstance(state, dict):
self._data = state["_data"]
self.name = state["name"]
self.index = self._data.index
elif isinstance(state, tuple):
# < 0.12 series pickle
nd_state, own_state = state
# recreate the ndarray
data = np.empty(nd_state[1], dtype=nd_state[2])
np.ndarray.__setstate__(data, nd_state)
# backwards compat
index, name = own_state[0], None
if len(own_state) > 1:
name = own_state[1]
# recreate
self._data = SingleBlockManager(data, index, fastpath=True)
self._index = index
self.name = name
else:
raise Exception("cannot unpickle legacy formats -> [%s]" % state)
# indexers
@property
def axes(self):
"""
Return a list of the row axis labels.
"""
return [self.index]
# ----------------------------------------------------------------------
# Indexing Methods
@Appender(generic.NDFrame.take.__doc__)
def take(self, indices, axis=0, is_copy=False, **kwargs):
nv.validate_take(tuple(), kwargs)
indices = ensure_platform_int(indices)
new_index = self.index.take(indices)
if is_categorical_dtype(self):
# https://github.com/pandas-dev/pandas/issues/20664
# TODO: remove when the default Categorical.take behavior changes
indices = maybe_convert_indices(indices, len(self._get_axis(axis)))
kwargs = {"allow_fill": False}
else:
kwargs = {}
new_values = self._values.take(indices, **kwargs)
result = self._constructor(
new_values, index=new_index, fastpath=True
).__finalize__(self)
# Maybe set copy if we didn't actually change the index.
if is_copy:
if not result._get_axis(axis).equals(self._get_axis(axis)):
result._set_is_copy(self)
return result
def _ixs(self, i: int, axis: int = 0):
"""
Return the i-th value or values in the Series by location.
Parameters
----------
i : int
Returns
-------
scalar (int) or Series (slice, sequence)
"""
# dispatch to the values if we need
values = self._values
if isinstance(values, np.ndarray):
return libindex.get_value_at(values, i)
else:
return values[i]
def _slice(self, slobj: slice, axis: int = 0, kind=None):
slobj = self.index._convert_slice_indexer(slobj, kind=kind or "getitem")
return self._get_values(slobj)
def __getitem__(self, key):
key = com.apply_if_callable(key, self)
try:
result = self.index.get_value(self, key)
if not is_scalar(result):
if is_list_like(result) and not isinstance(result, Series):
# we need to box if loc of the key isn't scalar here
# otherwise have inline ndarray/lists
try:
if not is_scalar(self.index.get_loc(key)):
result = self._constructor(
result, index=[key] * len(result), dtype=self.dtype
).__finalize__(self)
except KeyError:
pass
return result
except InvalidIndexError:
pass
except (KeyError, ValueError):
if isinstance(key, tuple) and isinstance(self.index, MultiIndex):
# kludge
pass
elif key is Ellipsis:
return self
elif com.is_bool_indexer(key):
pass
else:
# we can try to coerce the indexer (or this will raise)
new_key = self.index._convert_scalar_indexer(key, kind="getitem")
if type(new_key) != type(key):
return self.__getitem__(new_key)
raise
if is_iterator(key):
key = list(key)
if com.is_bool_indexer(key):
key = check_bool_indexer(self.index, key)
return self._get_with(key)
def _get_with(self, key):
# other: fancy integer or otherwise
if isinstance(key, slice):
return self._slice(key)
elif isinstance(key, ABCDataFrame):
raise TypeError(
"Indexing a Series with DataFrame is not "
"supported, use the appropriate DataFrame column"
)
elif isinstance(key, tuple):
try:
return self._get_values_tuple(key)
except Exception:
if len(key) == 1:
key = key[0]
if isinstance(key, slice):
return self._get_values(key)
raise
if not isinstance(key, (list, np.ndarray, Series, Index)):
key = list(key)
if isinstance(key, Index):
key_type = key.inferred_type
else:
key_type = lib.infer_dtype(key, skipna=False)
if key_type == "integer":
if self.index.is_integer() or self.index.is_floating():
return self.loc[key]
else:
return self._get_values(key)
elif key_type == "boolean":
return self._get_values(key)
if isinstance(key, (list, tuple)):
# TODO: de-dup with tuple case handled above?
# handle the dup indexing case GH#4246
if len(key) == 1 and isinstance(key[0], slice):
# [slice(0, 5, None)] will break if you convert to ndarray,
# e.g. as requested by np.median
# FIXME: hack
return self._get_values(key)
return self.loc[key]
return self.reindex(key)
def _get_values_tuple(self, key):
# mpl hackaround
if com.any_none(*key):
return self._get_values(key)
if not isinstance(self.index, MultiIndex):
raise ValueError("Can only tuple-index with a MultiIndex")
# If key is contained, would have returned by now
indexer, new_index = self.index.get_loc_level(key)
return self._constructor(self._values[indexer], index=new_index).__finalize__(
self
)
def _get_values(self, indexer):
try:
return self._constructor(
self._data.get_slice(indexer), fastpath=True
).__finalize__(self)
except Exception:
return self._values[indexer]
def _get_value(self, label, takeable: bool = False):
"""
Quickly retrieve single value at passed index label.
Parameters
----------
label : object
takeable : interpret the index as indexers, default False
Returns
-------
scalar value
"""
if takeable:
return com.maybe_box_datetimelike(self._values[label])
return self.index.get_value(self._values, label)
def __setitem__(self, key, value):
key = com.apply_if_callable(key, self)
cacher_needs_updating = self._check_is_chained_assignment_possible()
try:
self._set_with_engine(key, value)
except com.SettingWithCopyError:
raise
except (KeyError, ValueError):
values = self._values
if is_integer(key) and not self.index.inferred_type == "integer":
values[key] = value
elif key is Ellipsis:
self[:] = value
else:
self.loc[key] = value
except TypeError as e:
if isinstance(key, tuple) and not isinstance(self.index, MultiIndex):
raise ValueError("Can only tuple-index with a MultiIndex")
# python 3 type errors should be raised
if _is_unorderable_exception(e):
raise IndexError(key)
if com.is_bool_indexer(key):
key = check_bool_indexer(self.index, key)
try:
self._where(~key, value, inplace=True)
return
except InvalidIndexError:
pass
self._set_with(key, value)
if cacher_needs_updating:
self._maybe_update_cacher()
def _set_with_engine(self, key, value):
values = self._values
if is_extension_array_dtype(values.dtype):
# The cython indexing engine does not support ExtensionArrays.
values[self.index.get_loc(key)] = value
return
try:
self.index._engine.set_value(values, key, value)
return
except KeyError:
values[self.index.get_loc(key)] = value
return
def _set_with(self, key, value):
# other: fancy integer or otherwise
if isinstance(key, slice):
indexer = self.index._convert_slice_indexer(key, kind="getitem")
return self._set_values(indexer, value)
elif is_scalar(key) and not is_integer(key) and key not in self.index:
# GH#12862 adding an new key to the Series
# Note: have to exclude integers because that is ambiguously
# position-based
self.loc[key] = value
return
else:
if isinstance(key, tuple):
try:
self._set_values(key, value)
except Exception:
pass
if is_scalar(key):
key = [key]
elif not isinstance(key, (list, Series, np.ndarray)):
try:
key = list(key)
except Exception:
key = [key]
if isinstance(key, Index):
key_type = key.inferred_type
key = key._values
else:
key_type = lib.infer_dtype(key, skipna=False)
if key_type == "integer":
if self.index.inferred_type == "integer":
self._set_labels(key, value)
else:
return self._set_values(key, value)
elif key_type == "boolean":
self._set_values(key.astype(np.bool_), value)
else:
self._set_labels(key, value)
def _set_labels(self, key, value):
key = com.asarray_tuplesafe(key)
indexer = self.index.get_indexer(key)
mask = indexer == -1
if mask.any():
raise ValueError("%s not contained in the index" % str(key[mask]))
self._set_values(indexer, value)
def _set_values(self, key, value):
if isinstance(key, Series):
key = key._values
self._data = self._data.setitem(indexer=key, value=value)
self._maybe_update_cacher()
def _set_value(self, label, value, takeable: bool = False):
"""
Quickly set single value at passed label.
If label is not contained, a new object is created with the label
placed at the end of the result index.
Parameters
----------
label : object
Partial indexing with MultiIndex not allowed
value : object
Scalar value
takeable : interpret the index as indexers, default False
Returns
-------
Series
If label is contained, will be reference to calling Series,
otherwise a new object.
"""
try:
if takeable:
self._values[label] = value
else:
self.index._engine.set_value(self._values, label, value)
except (KeyError, TypeError):
# set using a non-recursive method
self.loc[label] = value
return self
# ----------------------------------------------------------------------
# Unsorted
@property
def _is_mixed_type(self):
return False
def repeat(self, repeats, axis=None):
"""
Repeat elements of a Series.
Returns a new Series where each element of the current Series
is repeated consecutively a given number of times.
Parameters
----------
repeats : int or array of ints
The number of repetitions for each element. This should be a
non-negative integer. Repeating 0 times will return an empty
Series.
axis : None
Must be ``None``. Has no effect but is accepted for compatibility
with numpy.
Returns
-------
Series
Newly created Series with repeated elements.
See Also
--------
Index.repeat : Equivalent function for Index.
numpy.repeat : Similar method for :class:`numpy.ndarray`.
Examples
--------
>>> s = pd.Series(['a', 'b', 'c'])
>>> s
0 a
1 b
2 c
dtype: object
>>> s.repeat(2)
0 a
0 a
1 b
1 b
2 c
2 c
dtype: object
>>> s.repeat([1, 2, 3])
0 a
1 b
1 b
2 c
2 c
2 c
dtype: object
"""
nv.validate_repeat(tuple(), dict(axis=axis))
new_index = self.index.repeat(repeats)
new_values = self._values.repeat(repeats)
return self._constructor(new_values, index=new_index).__finalize__(self)
def reset_index(self, level=None, drop=False, name=None, inplace=False):
"""
Generate a new DataFrame or Series with the index reset.
This is useful when the index needs to be treated as a column, or
when the index is meaningless and needs to be reset to the default
before another operation.
Parameters
----------
level : int, str, tuple, or list, default optional
For a Series with a MultiIndex, only remove the specified levels
from the index. Removes all levels by default.
drop : bool, default False
Just reset the index, without inserting it as a column in
the new DataFrame.
name : object, optional
The name to use for the column containing the original Series
values. Uses ``self.name`` by default. This argument is ignored
when `drop` is True.
inplace : bool, default False
Modify the Series in place (do not create a new object).
Returns
-------
Series or DataFrame
When `drop` is False (the default), a DataFrame is returned.
The newly created columns will come first in the DataFrame,
followed by the original Series values.
When `drop` is True, a `Series` is returned.
In either case, if ``inplace=True``, no value is returned.
See Also
--------
DataFrame.reset_index: Analogous function for DataFrame.
Examples
--------
>>> s = pd.Series([1, 2, 3, 4], name='foo',
... index=pd.Index(['a', 'b', 'c', 'd'], name='idx'))
Generate a DataFrame with default index.
>>> s.reset_index()
idx foo
0 a 1
1 b 2
2 c 3
3 d 4
To specify the name of the new column use `name`.
>>> s.reset_index(name='values')
idx values
0 a 1
1 b 2
2 c 3
3 d 4
To generate a new Series with the default set `drop` to True.
>>> s.reset_index(drop=True)
0 1
1 2
2 3
3 4
Name: foo, dtype: int64
To update the Series in place, without generating a new one
set `inplace` to True. Note that it also requires ``drop=True``.
>>> s.reset_index(inplace=True, drop=True)
>>> s
0 1
1 2
2 3
3 4
Name: foo, dtype: int64
The `level` parameter is interesting for Series with a multi-level
index.
>>> arrays = [np.array(['bar', 'bar', 'baz', 'baz']),
... np.array(['one', 'two', 'one', 'two'])]
>>> s2 = pd.Series(
... range(4), name='foo',
... index=pd.MultiIndex.from_arrays(arrays,
... names=['a', 'b']))
To remove a specific level from the Index, use `level`.
>>> s2.reset_index(level='a')
a foo
b
one bar 0
two bar 1
one baz 2
two baz 3
If `level` is not set, all levels are removed from the Index.
>>> s2.reset_index()
a b foo
0 bar one 0
1 bar two 1
2 baz one 2
3 baz two 3
"""
inplace = validate_bool_kwarg(inplace, "inplace")
if drop:
new_index = ibase.default_index(len(self))
if level is not None:
if not isinstance(level, (tuple, list)):
level = [level]
level = [self.index._get_level_number(lev) for lev in level]
if len(level) < self.index.nlevels:
new_index = self.index.droplevel(level)
if inplace:
self.index = new_index
# set name if it was passed, otherwise, keep the previous name
self.name = name or self.name
else:
return self._constructor(
self._values.copy(), index=new_index
).__finalize__(self)
elif inplace:
raise TypeError(
"Cannot reset_index inplace on a Series to create a DataFrame"
)
else:
df = self.to_frame(name)
return df.reset_index(level=level, drop=drop)
# ----------------------------------------------------------------------
# Rendering Methods
def __repr__(self):
"""
Return a string representation for a particular Series.
"""
buf = StringIO("")
width, height = get_terminal_size()
max_rows = (
height
if get_option("display.max_rows") == 0
else get_option("display.max_rows")
)
min_rows = (
height
if get_option("display.max_rows") == 0
else get_option("display.min_rows")
)
show_dimensions = get_option("display.show_dimensions")
self.to_string(
buf=buf,
name=self.name,
dtype=self.dtype,
min_rows=min_rows,
max_rows=max_rows,
length=show_dimensions,
)
result = buf.getvalue()
return result
def to_string(
self,
buf=None,
na_rep="NaN",
float_format=None,
header=True,
index=True,
length=False,
dtype=False,
name=False,
max_rows=None,
min_rows=None,
):
"""
Render a string representation of the Series.
Parameters
----------
buf : StringIO-like, optional
Buffer to write to.
na_rep : str, optional
String representation of NaN to use, default 'NaN'.
float_format : one-parameter function, optional
Formatter function to apply to columns' elements if they are
floats, default None.
header : bool, default True
Add the Series header (index name).
index : bool, optional
Add index (row) labels, default True.
length : bool, default False
Add the Series length.
dtype : bool, default False
Add the Series dtype.
name : bool, default False
Add the Series name if not None.
max_rows : int, optional
Maximum number of rows to show before truncating. If None, show
all.
min_rows : int, optional
The number of rows to display in a truncated repr (when number
of rows is above `max_rows`).
Returns
-------
str or None
String representation of Series if ``buf=None``, otherwise None.
"""
formatter = fmt.SeriesFormatter(
self,
name=name,
length=length,
header=header,
index=index,
dtype=dtype,
na_rep=na_rep,
float_format=float_format,
min_rows=min_rows,
max_rows=max_rows,
)
result = formatter.to_string()
# catch contract violations
if not isinstance(result, str):
raise AssertionError(
"result must be of type unicode, type"
" of result is {0!r}"
"".format(result.__class__.__name__)
)
if buf is None:
return result
else:
try:
buf.write(result)
except AttributeError:
with open(buf, "w") as f:
f.write(result)
# ----------------------------------------------------------------------
def items(self):
"""
Lazily iterate over (index, value) tuples.
This method returns an iterable tuple (index, value). This is
convenient if you want to create a lazy iterator.
Returns
-------
iterable
Iterable of tuples containing the (index, value) pairs from a
Series.
See Also
--------
DataFrame.items : Iterate over (column name, Series) pairs.
DataFrame.iterrows : Iterate over DataFrame rows as (index, Series) pairs.
Examples
--------
>>> s = pd.Series(['A', 'B', 'C'])
>>> for index, value in s.items():
... print("Index : {}, Value : {}".format(index, value))
Index : 0, Value : A
Index : 1, Value : B
Index : 2, Value : C
"""
return zip(iter(self.index), iter(self))
@Appender(items.__doc__)
def iteritems(self):
return self.items()
# ----------------------------------------------------------------------
# Misc public methods
def keys(self):
"""
Return alias for index.
Returns
-------
Index
Index of the Series.
"""
return self.index
def to_dict(self, into=dict):
"""
Convert Series to {label -> value} dict or dict-like object.
Parameters
----------
into : class, default dict
The collections.abc.Mapping subclass to use as the return
object. Can be the actual class or an empty
instance of the mapping type you want. If you want a
collections.defaultdict, you must pass it initialized.
.. versionadded:: 0.21.0
Returns
-------
collections.abc.Mapping
Key-value representation of Series.
Examples
--------
>>> s = pd.Series([1, 2, 3, 4])
>>> s.to_dict()
{0: 1, 1: 2, 2: 3, 3: 4}
>>> from collections import OrderedDict, defaultdict
>>> s.to_dict(OrderedDict)
OrderedDict([(0, 1), (1, 2), (2, 3), (3, 4)])
>>> dd = defaultdict(list)
>>> s.to_dict(dd)
defaultdict(<class 'list'>, {0: 1, 1: 2, 2: 3, 3: 4})
"""
# GH16122
into_c = com.standardize_mapping(into)
return into_c(self.items())
def to_frame(self, name=None):
"""
Convert Series to DataFrame.
Parameters
----------
name : object, default None
The passed name should substitute for the series name (if it has
one).
Returns
-------
DataFrame
DataFrame representation of Series.
Examples
--------
>>> s = pd.Series(["a", "b", "c"],
... name="vals")
>>> s.to_frame()
vals
0 a
1 b
2 c
"""
if name is None:
df = self._constructor_expanddim(self)
else:
df = self._constructor_expanddim({name: self})
return df
def to_sparse(self, kind="block", fill_value=None):
"""
Convert Series to SparseSeries.
.. deprecated:: 0.25.0
Parameters
----------
kind : {'block', 'integer'}, default 'block'
fill_value : float, defaults to NaN (missing)
Value to use for filling NaN values.
Returns
-------
SparseSeries
Sparse representation of the Series.
"""
warnings.warn(
"Series.to_sparse is deprecated and will be removed in a future version",
FutureWarning,
stacklevel=2,
)
from pandas.core.sparse.series import SparseSeries
values = SparseArray(self, kind=kind, fill_value=fill_value)
with warnings.catch_warnings():
warnings.filterwarnings("ignore", message="SparseSeries")
return SparseSeries(values, index=self.index, name=self.name).__finalize__(
self
)
def _set_name(self, name, inplace=False):
"""
Set the Series name.
Parameters
----------
name : str
inplace : bool
whether to modify `self` directly or return a copy
"""
inplace = validate_bool_kwarg(inplace, "inplace")
ser = self if inplace else self.copy()
ser.name = name
return ser
# ----------------------------------------------------------------------
# Statistics, overridden ndarray methods
# TODO: integrate bottleneck
def count(self, level=None):
"""
Return number of non-NA/null observations in the Series.
Parameters
----------
level : int or level name, default None
If the axis is a MultiIndex (hierarchical), count along a
particular level, collapsing into a smaller Series.
Returns
-------
int or Series (if level specified)
Number of non-null values in the Series.
Examples
--------
>>> s = pd.Series([0.0, 1.0, np.nan])
>>> s.count()
2
"""
if level is None:
return notna(self.array).sum()
if isinstance(level, str):
level = self.index._get_level_number(level)
lev = self.index.levels[level]
level_codes = np.array(self.index.codes[level], subok=False, copy=True)
mask = level_codes == -1
if mask.any():
level_codes[mask] = cnt = len(lev)
lev = lev.insert(cnt, lev._na_value)
obs = level_codes[notna(self.values)]
out = np.bincount(obs, minlength=len(lev) or None)
return self._constructor(out, index=lev, dtype="int64").__finalize__(self)
def mode(self, dropna=True):
"""
Return the mode(s) of the dataset.
Always returns Series even if only one value is returned.
Parameters
----------
dropna : bool, default True
Don't consider counts of NaN/NaT.
.. versionadded:: 0.24.0
Returns
-------
Series
Modes of the Series in sorted order.
"""
# TODO: Add option for bins like value_counts()
return algorithms.mode(self, dropna=dropna)
def unique(self):
"""
Return unique values of Series object.
Uniques are returned in order of appearance. Hash table-based unique,
therefore does NOT sort.
Returns
-------
ndarray or ExtensionArray
The unique values returned as a NumPy array. See Notes.
See Also
--------
unique : Top-level unique method for any 1-d array-like object.
Index.unique : Return Index with unique values from an Index object.
Notes
-----
Returns the unique values as a NumPy array. In case of an
extension-array backed Series, a new
:class:`~api.extensions.ExtensionArray` of that type with just
the unique values is returned. This includes
* Categorical
* Period
* Datetime with Timezone
* Interval
* Sparse
* IntegerNA
See Examples section.
Examples
--------
>>> pd.Series([2, 1, 3, 3], name='A').unique()
array([2, 1, 3])
>>> pd.Series([pd.Timestamp('2016-01-01') for _ in range(3)]).unique()
array(['2016-01-01T00:00:00.000000000'], dtype='datetime64[ns]')
>>> pd.Series([pd.Timestamp('2016-01-01', tz='US/Eastern')
... for _ in range(3)]).unique()
<DatetimeArray>
['2016-01-01 00:00:00-05:00']
Length: 1, dtype: datetime64[ns, US/Eastern]
An unordered Categorical will return categories in the order of
appearance.
>>> pd.Series(pd.Categorical(list('baabc'))).unique()
[b, a, c]
Categories (3, object): [b, a, c]
An ordered Categorical preserves the category ordering.
>>> pd.Series(pd.Categorical(list('baabc'), categories=list('abc'),
... ordered=True)).unique()
[b, a, c]
Categories (3, object): [a < b < c]
"""
result = super().unique()
return result
def drop_duplicates(self, keep="first", inplace=False):
"""
Return Series with duplicate values removed.
Parameters
----------
keep : {'first', 'last', ``False``}, default 'first'
- 'first' : Drop duplicates except for the first occurrence.
- 'last' : Drop duplicates except for the last occurrence.
- ``False`` : Drop all duplicates.
inplace : bool, default ``False``
If ``True``, performs operation inplace and returns None.
Returns
-------
Series
Series with duplicates dropped.
See Also
--------
Index.drop_duplicates : Equivalent method on Index.
DataFrame.drop_duplicates : Equivalent method on DataFrame.
Series.duplicated : Related method on Series, indicating duplicate
Series values.
Examples
--------
Generate a Series with duplicated entries.
>>> s = pd.Series(['lama', 'cow', 'lama', 'beetle', 'lama', 'hippo'],
... name='animal')
>>> s
0 lama
1 cow
2 lama
3 beetle
4 lama
5 hippo
Name: animal, dtype: object
With the 'keep' parameter, the selection behaviour of duplicated values
can be changed. The value 'first' keeps the first occurrence for each
set of duplicated entries. The default value of keep is 'first'.
>>> s.drop_duplicates()
0 lama
1 cow
3 beetle
5 hippo
Name: animal, dtype: object
The value 'last' for parameter 'keep' keeps the last occurrence for
each set of duplicated entries.
>>> s.drop_duplicates(keep='last')
1 cow
3 beetle
4 lama
5 hippo
Name: animal, dtype: object
The value ``False`` for parameter 'keep' discards all sets of
duplicated entries. Setting the value of 'inplace' to ``True`` performs
the operation inplace and returns ``None``.
>>> s.drop_duplicates(keep=False, inplace=True)
>>> s
1 cow
3 beetle
5 hippo
Name: animal, dtype: object
"""
return super().drop_duplicates(keep=keep, inplace=inplace)
def duplicated(self, keep="first"):
"""
Indicate duplicate Series values.
Duplicated values are indicated as ``True`` values in the resulting
Series. Either all duplicates, all except the first or all except the
last occurrence of duplicates can be indicated.
Parameters
----------
keep : {'first', 'last', False}, default 'first'
- 'first' : Mark duplicates as ``True`` except for the first
occurrence.
- 'last' : Mark duplicates as ``True`` except for the last
occurrence.
- ``False`` : Mark all duplicates as ``True``.
Returns
-------
Series
Series indicating whether each value has occurred in the
preceding values.
See Also
--------
Index.duplicated : Equivalent method on pandas.Index.
DataFrame.duplicated : Equivalent method on pandas.DataFrame.
Series.drop_duplicates : Remove duplicate values from Series.
Examples
--------
By default, for each set of duplicated values, the first occurrence is
set on False and all others on True:
>>> animals = pd.Series(['lama', 'cow', 'lama', 'beetle', 'lama'])
>>> animals.duplicated()
0 False
1 False
2 True
3 False
4 True
dtype: bool
which is equivalent to
>>> animals.duplicated(keep='first')
0 False
1 False
2 True
3 False
4 True
dtype: bool
By using 'last', the last occurrence of each set of duplicated values
is set on False and all others on True:
>>> animals.duplicated(keep='last')
0 True
1 False
2 True
3 False
4 False
dtype: bool
By setting keep on ``False``, all duplicates are True:
>>> animals.duplicated(keep=False)
0 True
1 False
2 True
3 False
4 True
dtype: bool
"""
return super().duplicated(keep=keep)
def idxmin(self, axis=0, skipna=True, *args, **kwargs):
"""
Return the row label of the minimum value.
If multiple values equal the minimum, the first row label with that
value is returned.
Parameters
----------
skipna : bool, default True
Exclude NA/null values. If the entire Series is NA, the result
will be NA.
axis : int, default 0
For compatibility with DataFrame.idxmin. Redundant for application
on Series.
*args, **kwargs
Additional keywords have no effect but might be accepted
for compatibility with NumPy.
Returns
-------
Index
Label of the minimum value.
Raises
------
ValueError
If the Series is empty.
See Also
--------
numpy.argmin : Return indices of the minimum values
along the given axis.
DataFrame.idxmin : Return index of first occurrence of minimum
over requested axis.
Series.idxmax : Return index *label* of the first occurrence
of maximum of values.
Notes
-----
This method is the Series version of ``ndarray.argmin``. This method
returns the label of the minimum, while ``ndarray.argmin`` returns
the position. To get the position, use ``series.values.argmin()``.
Examples
--------
>>> s = pd.Series(data=[1, None, 4, 1],
... index=['A', 'B', 'C', 'D'])
>>> s
A 1.0
B NaN
C 4.0
D 1.0
dtype: float64
>>> s.idxmin()
'A'
If `skipna` is False and there is an NA value in the data,
the function returns ``nan``.
>>> s.idxmin(skipna=False)
nan
"""
skipna = nv.validate_argmin_with_skipna(skipna, args, kwargs)
i = nanops.nanargmin(com.values_from_object(self), skipna=skipna)
if i == -1:
return np.nan
return self.index[i]
def idxmax(self, axis=0, skipna=True, *args, **kwargs):
"""
Return the row label of the maximum value.
If multiple values equal the maximum, the first row label with that
value is returned.
Parameters
----------
skipna : bool, default True
Exclude NA/null values. If the entire Series is NA, the result
will be NA.
axis : int, default 0
For compatibility with DataFrame.idxmax. Redundant for application
on Series.
*args, **kwargs
Additional keywords have no effect but might be accepted
for compatibility with NumPy.
Returns
-------
Index
Label of the maximum value.
Raises
------
ValueError
If the Series is empty.
See Also
--------
numpy.argmax : Return indices of the maximum values
along the given axis.
DataFrame.idxmax : Return index of first occurrence of maximum
over requested axis.
Series.idxmin : Return index *label* of the first occurrence
of minimum of values.
Notes
-----
This method is the Series version of ``ndarray.argmax``. This method
returns the label of the maximum, while ``ndarray.argmax`` returns
the position. To get the position, use ``series.values.argmax()``.
Examples
--------
>>> s = pd.Series(data=[1, None, 4, 3, 4],
... index=['A', 'B', 'C', 'D', 'E'])
>>> s
A 1.0
B NaN
C 4.0
D 3.0
E 4.0
dtype: float64
>>> s.idxmax()
'C'
If `skipna` is False and there is an NA value in the data,
the function returns ``nan``.
>>> s.idxmax(skipna=False)
nan
"""
skipna = nv.validate_argmax_with_skipna(skipna, args, kwargs)
i = nanops.nanargmax(com.values_from_object(self), skipna=skipna)
if i == -1:
return np.nan
return self.index[i]
# ndarray compat
argmin = deprecate(
"argmin",
idxmin,
"0.21.0",
msg=dedent(
"""
The current behaviour of 'Series.argmin' is deprecated, use 'idxmin'
instead.
The behavior of 'argmin' will be corrected to return the positional
minimum in the future. For now, use 'series.values.argmin' or
'np.argmin(np.array(values))' to get the position of the minimum
row."""
),
)
argmax = deprecate(
"argmax",
idxmax,
"0.21.0",
msg=dedent(
"""
The current behaviour of 'Series.argmax' is deprecated, use 'idxmax'
instead.
The behavior of 'argmax' will be corrected to return the positional
maximum in the future. For now, use 'series.values.argmax' or
'np.argmax(np.array(values))' to get the position of the maximum
row."""
),
)
def round(self, decimals=0, *args, **kwargs):
"""
Round each value in a Series to the given number of decimals.
Parameters
----------
decimals : int
Number of decimal places to round to (default: 0).
If decimals is negative, it specifies the number of
positions to the left of the decimal point.
Returns
-------
Series
Rounded values of the Series.
See Also
--------
numpy.around : Round values of an np.array.
DataFrame.round : Round values of a DataFrame.
Examples
--------
>>> s = pd.Series([0.1, 1.3, 2.7])
>>> s.round()
0 0.0
1 1.0
2 3.0
dtype: float64
"""
nv.validate_round(args, kwargs)
result = com.values_from_object(self).round(decimals)
result = self._constructor(result, index=self.index).__finalize__(self)
return result
def quantile(self, q=0.5, interpolation="linear"):
"""
Return value at the given quantile.
Parameters
----------
q : float or array-like, default 0.5 (50% quantile)
0 <= q <= 1, the quantile(s) to compute.
interpolation : {'linear', 'lower', 'higher', 'midpoint', 'nearest'}
This optional parameter specifies the interpolation method to use,
when the desired quantile lies between two data points `i` and `j`:
* linear: `i + (j - i) * fraction`, where `fraction` is the
fractional part of the index surrounded by `i` and `j`.
* lower: `i`.
* higher: `j`.
* nearest: `i` or `j` whichever is nearest.
* midpoint: (`i` + `j`) / 2.
Returns
-------
float or Series
If ``q`` is an array, a Series will be returned where the
index is ``q`` and the values are the quantiles, otherwise
a float will be returned.
See Also
--------
core.window.Rolling.quantile
numpy.percentile
Examples
--------
>>> s = pd.Series([1, 2, 3, 4])
>>> s.quantile(.5)
2.5
>>> s.quantile([.25, .5, .75])
0.25 1.75
0.50 2.50
0.75 3.25
dtype: float64
"""
self._check_percentile(q)
# We dispatch to DataFrame so that core.internals only has to worry
# about 2D cases.
df = self.to_frame()
result = df.quantile(q=q, interpolation=interpolation, numeric_only=False)
if result.ndim == 2:
result = result.iloc[:, 0]
if is_list_like(q):
result.name = self.name
return self._constructor(result, index=Float64Index(q), name=self.name)
else:
# scalar
return result.iloc[0]
def corr(self, other, method="pearson", min_periods=None):
"""
Compute correlation with `other` Series, excluding missing values.
Parameters
----------
other : Series
Series with which to compute the correlation.
method : {'pearson', 'kendall', 'spearman'} or callable
* pearson : standard correlation coefficient
* kendall : Kendall Tau correlation coefficient
* spearman : Spearman rank correlation
* callable: callable with input two 1d ndarrays
and returning a float. Note that the returned matrix from corr
will have 1 along the diagonals and will be symmetric
regardless of the callable's behavior
.. versionadded:: 0.24.0
min_periods : int, optional
Minimum number of observations needed to have a valid result.
Returns
-------
float
Correlation with other.
Examples
--------
>>> def histogram_intersection(a, b):
... v = np.minimum(a, b).sum().round(decimals=1)
... return v
>>> s1 = pd.Series([.2, .0, .6, .2])
>>> s2 = pd.Series([.3, .6, .0, .1])
>>> s1.corr(s2, method=histogram_intersection)
0.3
"""
this, other = self.align(other, join="inner", copy=False)
if len(this) == 0:
return np.nan
if method in ["pearson", "spearman", "kendall"] or callable(method):
return nanops.nancorr(
this.values, other.values, method=method, min_periods=min_periods
)
raise ValueError(
"method must be either 'pearson', "
"'spearman', 'kendall', or a callable, "
"'{method}' was supplied".format(method=method)
)
def cov(self, other, min_periods=None):
"""
Compute covariance with Series, excluding missing values.
Parameters
----------
other : Series
Series with which to compute the covariance.
min_periods : int, optional
Minimum number of observations needed to have a valid result.
Returns
-------
float
Covariance between Series and other normalized by N-1
(unbiased estimator).
Examples
--------
>>> s1 = pd.Series([0.90010907, 0.13484424, 0.62036035])
>>> s2 = pd.Series([0.12528585, 0.26962463, 0.51111198])
>>> s1.cov(s2)
-0.01685762652715874
"""
this, other = self.align(other, join="inner", copy=False)
if len(this) == 0:
return np.nan
return nanops.nancov(this.values, other.values, min_periods=min_periods)
def diff(self, periods=1):
"""
First discrete difference of element.
Calculates the difference of a Series element compared with another
element in the Series (default is element in previous row).
Parameters
----------
periods : int, default 1
Periods to shift for calculating difference, accepts negative
values.
Returns
-------
Series
First differences of the Series.
See Also
--------
Series.pct_change: Percent change over given number of periods.
Series.shift: Shift index by desired number of periods with an
optional time freq.
DataFrame.diff: First discrete difference of object.
Examples
--------
Difference with previous row
>>> s = pd.Series([1, 1, 2, 3, 5, 8])
>>> s.diff()
0 NaN
1 0.0
2 1.0
3 1.0
4 2.0
5 3.0
dtype: float64
Difference with 3rd previous row
>>> s.diff(periods=3)
0 NaN
1 NaN
2 NaN
3 2.0
4 4.0
5 6.0
dtype: float64
Difference with following row
>>> s.diff(periods=-1)
0 0.0
1 -1.0
2 -1.0
3 -2.0
4 -3.0
5 NaN
dtype: float64
"""
result = algorithms.diff(com.values_from_object(self), periods)
return self._constructor(result, index=self.index).__finalize__(self)
def autocorr(self, lag=1):
"""
Compute the lag-N autocorrelation.
This method computes the Pearson correlation between
the Series and its shifted self.
Parameters
----------
lag : int, default 1
Number of lags to apply before performing autocorrelation.
Returns
-------
float
The Pearson correlation between self and self.shift(lag).
See Also
--------
Series.corr : Compute the correlation between two Series.
Series.shift : Shift index by desired number of periods.
DataFrame.corr : Compute pairwise correlation of columns.
DataFrame.corrwith : Compute pairwise correlation between rows or
columns of two DataFrame objects.
Notes
-----
If the Pearson correlation is not well defined return 'NaN'.
Examples
--------
>>> s = pd.Series([0.25, 0.5, 0.2, -0.05])
>>> s.autocorr() # doctest: +ELLIPSIS
0.10355...
>>> s.autocorr(lag=2) # doctest: +ELLIPSIS
-0.99999...
If the Pearson correlation is not well defined, then 'NaN' is returned.
>>> s = pd.Series([1, 0, 0, 0])
>>> s.autocorr()
nan
"""
return self.corr(self.shift(lag))
def dot(self, other):
"""
Compute the dot product between the Series and the columns of other.
This method computes the dot product between the Series and another
one, or the Series and each columns of a DataFrame, or the Series and
each columns of an array.
It can also be called using `self @ other` in Python >= 3.5.
Parameters
----------
other : Series, DataFrame or array-like
The other object to compute the dot product with its columns.
Returns
-------
scalar, Series or numpy.ndarray
Return the dot product of the Series and other if other is a
Series, the Series of the dot product of Series and each rows of
other if other is a DataFrame or a numpy.ndarray between the Series
and each columns of the numpy array.
See Also
--------
DataFrame.dot: Compute the matrix product with the DataFrame.
Series.mul: Multiplication of series and other, element-wise.
Notes
-----
The Series and other has to share the same index if other is a Series
or a DataFrame.
Examples
--------
>>> s = pd.Series([0, 1, 2, 3])
>>> other = pd.Series([-1, 2, -3, 4])
>>> s.dot(other)
8
>>> s @ other
8
>>> df = pd.DataFrame([[0, 1], [-2, 3], [4, -5], [6, 7]])
>>> s.dot(df)
0 24
1 14
dtype: int64
>>> arr = np.array([[0, 1], [-2, 3], [4, -5], [6, 7]])
>>> s.dot(arr)
array([24, 14])
"""
if isinstance(other, (Series, ABCDataFrame)):
common = self.index.union(other.index)
if len(common) > len(self.index) or len(common) > len(other.index):
raise ValueError("matrices are not aligned")
left = self.reindex(index=common, copy=False)
right = other.reindex(index=common, copy=False)
lvals = left.values
rvals = right.values
else:
lvals = self.values
rvals = np.asarray(other)
if lvals.shape[0] != rvals.shape[0]:
raise Exception(
"Dot product shape mismatch, %s vs %s" % (lvals.shape, rvals.shape)
)
if isinstance(other, ABCDataFrame):
return self._constructor(
np.dot(lvals, rvals), index=other.columns
).__finalize__(self)
elif isinstance(other, Series):
return np.dot(lvals, rvals)
elif isinstance(rvals, np.ndarray):
return np.dot(lvals, rvals)
else: # pragma: no cover
raise TypeError("unsupported type: %s" % type(other))
def __matmul__(self, other):
"""
Matrix multiplication using binary `@` operator in Python>=3.5.
"""
return self.dot(other)
def __rmatmul__(self, other):
"""
Matrix multiplication using binary `@` operator in Python>=3.5.
"""
return self.dot(np.transpose(other))
@Substitution(klass="Series")
@Appender(base._shared_docs["searchsorted"])
def searchsorted(self, value, side="left", sorter=None):
return algorithms.searchsorted(self._values, value, side=side, sorter=sorter)
# -------------------------------------------------------------------
# Combination
def append(self, to_append, ignore_index=False, verify_integrity=False):
"""
Concatenate two or more Series.
Parameters
----------
to_append : Series or list/tuple of Series
Series to append with self.
ignore_index : bool, default False
If True, do not use the index labels.
verify_integrity : bool, default False
If True, raise Exception on creating index with duplicates.
Returns
-------
Series
Concatenated Series.
See Also
--------
concat : General function to concatenate DataFrame or Series objects.
Notes
-----
Iteratively appending to a Series can be more computationally intensive
than a single concatenate. A better solution is to append values to a
list and then concatenate the list with the original Series all at
once.
Examples
--------
>>> s1 = pd.Series([1, 2, 3])
>>> s2 = pd.Series([4, 5, 6])
>>> s3 = pd.Series([4, 5, 6], index=[3, 4, 5])
>>> s1.append(s2)
0 1
1 2
2 3
0 4
1 5
2 6
dtype: int64
>>> s1.append(s3)
0 1
1 2
2 3
3 4
4 5
5 6
dtype: int64
With `ignore_index` set to True:
>>> s1.append(s2, ignore_index=True)
0 1
1 2
2 3
3 4
4 5
5 6
dtype: int64
With `verify_integrity` set to True:
>>> s1.append(s2, verify_integrity=True)
Traceback (most recent call last):
...
ValueError: Indexes have overlapping values: [0, 1, 2]
"""
from pandas.core.reshape.concat import concat
if isinstance(to_append, (list, tuple)):
to_concat = [self]
to_concat.extend(to_append)
else:
to_concat = [self, to_append]
return concat(
to_concat, ignore_index=ignore_index, verify_integrity=verify_integrity
)
def _binop(self, other, func, level=None, fill_value=None):
"""
Perform generic binary operation with optional fill value.
Parameters
----------
other : Series
func : binary operator
fill_value : float or object
Value to substitute for NA/null values. If both Series are NA in a
location, the result will be NA regardless of the passed fill value
level : int or level name, default None
Broadcast across a level, matching Index values on the
passed MultiIndex level
Returns
-------
Series
"""
if not isinstance(other, Series):
raise AssertionError("Other operand must be Series")
new_index = self.index
this = self
if not self.index.equals(other.index):
this, other = self.align(other, level=level, join="outer", copy=False)
new_index = this.index
this_vals, other_vals = ops.fill_binop(this.values, other.values, fill_value)
with np.errstate(all="ignore"):
result = func(this_vals, other_vals)
name = ops.get_op_result_name(self, other)
if func.__name__ in ["divmod", "rdivmod"]:
ret = ops._construct_divmod_result(self, result, new_index, name)
else:
ret = ops._construct_result(self, result, new_index, name)
return ret
def combine(self, other, func, fill_value=None):
"""
Combine the Series with a Series or scalar according to `func`.
Combine the Series and `other` using `func` to perform elementwise
selection for combined Series.
`fill_value` is assumed when value is missing at some index
from one of the two objects being combined.
Parameters
----------
other : Series or scalar
The value(s) to be combined with the `Series`.
func : function
Function that takes two scalars as inputs and returns an element.
fill_value : scalar, optional
The value to assume when an index is missing from
one Series or the other. The default specifies to use the
appropriate NaN value for the underlying dtype of the Series.
Returns
-------
Series
The result of combining the Series with the other object.
See Also
--------
Series.combine_first : Combine Series values, choosing the calling
Series' values first.
Examples
--------
Consider 2 Datasets ``s1`` and ``s2`` containing
highest clocked speeds of different birds.
>>> s1 = pd.Series({'falcon': 330.0, 'eagle': 160.0})
>>> s1
falcon 330.0
eagle 160.0
dtype: float64
>>> s2 = pd.Series({'falcon': 345.0, 'eagle': 200.0, 'duck': 30.0})
>>> s2
falcon 345.0
eagle 200.0
duck 30.0
dtype: float64
Now, to combine the two datasets and view the highest speeds
of the birds across the two datasets
>>> s1.combine(s2, max)
duck NaN
eagle 200.0
falcon 345.0
dtype: float64
In the previous example, the resulting value for duck is missing,
because the maximum of a NaN and a float is a NaN.
So, in the example, we set ``fill_value=0``,
so the maximum value returned will be the value from some dataset.
>>> s1.combine(s2, max, fill_value=0)
duck 30.0
eagle 200.0
falcon 345.0
dtype: float64
"""
if fill_value is None:
fill_value = na_value_for_dtype(self.dtype, compat=False)
if isinstance(other, Series):
# If other is a Series, result is based on union of Series,
# so do this element by element
new_index = self.index.union(other.index)
new_name = ops.get_op_result_name(self, other)
new_values = []
for idx in new_index:
lv = self.get(idx, fill_value)
rv = other.get(idx, fill_value)
with np.errstate(all="ignore"):
new_values.append(func(lv, rv))
else:
# Assume that other is a scalar, so apply the function for
# each element in the Series
new_index = self.index
with np.errstate(all="ignore"):
new_values = [func(lv, other) for lv in self._values]
new_name = self.name
if is_categorical_dtype(self.values):
pass
elif is_extension_array_dtype(self.values):
# The function can return something of any type, so check
# if the type is compatible with the calling EA.
try:
new_values = self._values._from_sequence(new_values)
except Exception:
# https://github.com/pandas-dev/pandas/issues/22850
# pandas has no control over what 3rd-party ExtensionArrays
# do in _values_from_sequence. We still want ops to work
# though, so we catch any regular Exception.
pass
return self._constructor(new_values, index=new_index, name=new_name)
def combine_first(self, other):
"""
Combine Series values, choosing the calling Series's values first.
Parameters
----------
other : Series
The value(s) to be combined with the `Series`.
Returns
-------
Series
The result of combining the Series with the other object.
See Also
--------
Series.combine : Perform elementwise operation on two Series
using a given function.
Notes
-----
Result index will be the union of the two indexes.
Examples
--------
>>> s1 = pd.Series([1, np.nan])
>>> s2 = pd.Series([3, 4])
>>> s1.combine_first(s2)
0 1.0
1 4.0
dtype: float64
"""
new_index = self.index.union(other.index)
this = self.reindex(new_index, copy=False)
other = other.reindex(new_index, copy=False)
if is_datetimelike(this) and not is_datetimelike(other):
other = to_datetime(other)
return this.where(notna(this), other)
def update(self, other):
"""
Modify Series in place using non-NA values from passed
Series. Aligns on index.
Parameters
----------
other : Series
Examples
--------
>>> s = pd.Series([1, 2, 3])
>>> s.update(pd.Series([4, 5, 6]))
>>> s
0 4
1 5
2 6
dtype: int64
>>> s = pd.Series(['a', 'b', 'c'])
>>> s.update(pd.Series(['d', 'e'], index=[0, 2]))
>>> s
0 d
1 b
2 e
dtype: object
>>> s = pd.Series([1, 2, 3])
>>> s.update(pd.Series([4, 5, 6, 7, 8]))
>>> s
0 4
1 5
2 6
dtype: int64
If ``other`` contains NaNs the corresponding values are not updated
in the original Series.
>>> s = pd.Series([1, 2, 3])
>>> s.update(pd.Series([4, np.nan, 6]))
>>> s
0 4
1 2
2 6
dtype: int64
"""
other = other.reindex_like(self)
mask = notna(other)
self._data = self._data.putmask(mask=mask, new=other, inplace=True)
self._maybe_update_cacher()
# ----------------------------------------------------------------------
# Reindexing, sorting
def sort_values(
self,
axis=0,
ascending=True,
inplace=False,
kind="quicksort",
na_position="last",
):
"""
Sort by the values.
Sort a Series in ascending or descending order by some
criterion.
Parameters
----------
axis : {0 or 'index'}, default 0
Axis to direct sorting. The value 'index' is accepted for
compatibility with DataFrame.sort_values.
ascending : bool, default True
If True, sort values in ascending order, otherwise descending.
inplace : bool, default False
If True, perform operation in-place.
kind : {'quicksort', 'mergesort' or 'heapsort'}, default 'quicksort'
Choice of sorting algorithm. See also :func:`numpy.sort` for more
information. 'mergesort' is the only stable algorithm.
na_position : {'first' or 'last'}, default 'last'
Argument 'first' puts NaNs at the beginning, 'last' puts NaNs at
the end.
Returns
-------
Series
Series ordered by values.
See Also
--------
Series.sort_index : Sort by the Series indices.
DataFrame.sort_values : Sort DataFrame by the values along either axis.
DataFrame.sort_index : Sort DataFrame by indices.
Examples
--------
>>> s = pd.Series([np.nan, 1, 3, 10, 5])
>>> s
0 NaN
1 1.0
2 3.0
3 10.0
4 5.0
dtype: float64
Sort values ascending order (default behaviour)
>>> s.sort_values(ascending=True)
1 1.0
2 3.0
4 5.0
3 10.0
0 NaN
dtype: float64
Sort values descending order
>>> s.sort_values(ascending=False)
3 10.0
4 5.0
2 3.0
1 1.0
0 NaN
dtype: float64
Sort values inplace
>>> s.sort_values(ascending=False, inplace=True)
>>> s
3 10.0
4 5.0
2 3.0
1 1.0
0 NaN
dtype: float64
Sort values putting NAs first
>>> s.sort_values(na_position='first')
0 NaN
1 1.0
2 3.0
4 5.0
3 10.0
dtype: float64
Sort a series of strings
>>> s = pd.Series(['z', 'b', 'd', 'a', 'c'])
>>> s
0 z
1 b
2 d
3 a
4 c
dtype: object
>>> s.sort_values()
3 a
1 b
4 c
2 d
0 z
dtype: object
"""
inplace = validate_bool_kwarg(inplace, "inplace")
# Validate the axis parameter
self._get_axis_number(axis)
# GH 5856/5853
if inplace and self._is_cached:
raise ValueError(
"This Series is a view of some other array, to "
"sort in-place you must create a copy"
)
def _try_kind_sort(arr):
# easier to ask forgiveness than permission
try:
# if kind==mergesort, it can fail for object dtype
return arr.argsort(kind=kind)
except TypeError:
# stable sort not available for object dtype
# uses the argsort default quicksort
return arr.argsort(kind="quicksort")
arr = self._values
sortedIdx = np.empty(len(self), dtype=np.int32)
bad = isna(arr)
good = ~bad
idx = ibase.default_index(len(self))
argsorted = _try_kind_sort(arr[good])
if is_list_like(ascending):
if len(ascending) != 1:
raise ValueError(
"Length of ascending (%d) must be 1 "
"for Series" % (len(ascending))
)
ascending = ascending[0]
if not is_bool(ascending):
raise ValueError("ascending must be boolean")
if not ascending:
argsorted = argsorted[::-1]
if na_position == "last":
n = good.sum()
sortedIdx[:n] = idx[good][argsorted]
sortedIdx[n:] = idx[bad]
elif na_position == "first":
n = bad.sum()
sortedIdx[n:] = idx[good][argsorted]
sortedIdx[:n] = idx[bad]
else:
raise ValueError("invalid na_position: {!r}".format(na_position))
result = self._constructor(arr[sortedIdx], index=self.index[sortedIdx])
if inplace:
self._update_inplace(result)
else:
return result.__finalize__(self)
def sort_index(
self,
axis=0,
level=None,
ascending=True,
inplace=False,
kind="quicksort",
na_position="last",
sort_remaining=True,
):
"""
Sort Series by index labels.
Returns a new Series sorted by label if `inplace` argument is
``False``, otherwise updates the original series and returns None.
Parameters
----------
axis : int, default 0
Axis to direct sorting. This can only be 0 for Series.
level : int, optional
If not None, sort on values in specified index level(s).
ascending : bool, default true
Sort ascending vs. descending.
inplace : bool, default False
If True, perform operation in-place.
kind : {'quicksort', 'mergesort', 'heapsort'}, default 'quicksort'
Choice of sorting algorithm. See also :func:`numpy.sort` for more
information. 'mergesort' is the only stable algorithm. For
DataFrames, this option is only applied when sorting on a single
column or label.
na_position : {'first', 'last'}, default 'last'
If 'first' puts NaNs at the beginning, 'last' puts NaNs at the end.
Not implemented for MultiIndex.
sort_remaining : bool, default True
If True and sorting by level and index is multilevel, sort by other
levels too (in order) after sorting by specified level.
Returns
-------
Series
The original Series sorted by the labels.
See Also
--------
DataFrame.sort_index: Sort DataFrame by the index.
DataFrame.sort_values: Sort DataFrame by the value.
Series.sort_values : Sort Series by the value.
Examples
--------
>>> s = pd.Series(['a', 'b', 'c', 'd'], index=[3, 2, 1, 4])
>>> s.sort_index()
1 c
2 b
3 a
4 d
dtype: object
Sort Descending
>>> s.sort_index(ascending=False)
4 d
3 a
2 b
1 c
dtype: object
Sort Inplace
>>> s.sort_index(inplace=True)
>>> s
1 c
2 b
3 a
4 d
dtype: object
By default NaNs are put at the end, but use `na_position` to place
them at the beginning
>>> s = pd.Series(['a', 'b', 'c', 'd'], index=[3, 2, 1, np.nan])
>>> s.sort_index(na_position='first')
NaN d
1.0 c
2.0 b
3.0 a
dtype: object
Specify index level to sort
>>> arrays = [np.array(['qux', 'qux', 'foo', 'foo',
... 'baz', 'baz', 'bar', 'bar']),
... np.array(['two', 'one', 'two', 'one',
... 'two', 'one', 'two', 'one'])]
>>> s = pd.Series([1, 2, 3, 4, 5, 6, 7, 8], index=arrays)
>>> s.sort_index(level=1)
bar one 8
baz one 6
foo one 4
qux one 2
bar two 7
baz two 5
foo two 3
qux two 1
dtype: int64
Does not sort by remaining levels when sorting by levels
>>> s.sort_index(level=1, sort_remaining=False)
qux one 2
foo one 4
baz one 6
bar one 8
qux two 1
foo two 3
baz two 5
bar two 7
dtype: int64
"""
# TODO: this can be combined with DataFrame.sort_index impl as
# almost identical
inplace = validate_bool_kwarg(inplace, "inplace")
# Validate the axis parameter
self._get_axis_number(axis)
index = self.index
if level is not None:
new_index, indexer = index.sortlevel(
level, ascending=ascending, sort_remaining=sort_remaining
)
elif isinstance(index, MultiIndex):
from pandas.core.sorting import lexsort_indexer
labels = index._sort_levels_monotonic()
indexer = lexsort_indexer(
labels._get_codes_for_sorting(),
orders=ascending,
na_position=na_position,
)
else:
from pandas.core.sorting import nargsort
# Check monotonic-ness before sort an index
# GH11080
if (ascending and index.is_monotonic_increasing) or (
not ascending and index.is_monotonic_decreasing
):
if inplace:
return
else:
return self.copy()
indexer = nargsort(
index, kind=kind, ascending=ascending, na_position=na_position
)
indexer = ensure_platform_int(indexer)
new_index = index.take(indexer)
new_index = new_index._sort_levels_monotonic()
new_values = self._values.take(indexer)
result = self._constructor(new_values, index=new_index)
if inplace:
self._update_inplace(result)
else:
return result.__finalize__(self)
def argsort(self, axis=0, kind="quicksort", order=None):
"""
Override ndarray.argsort. Argsorts the value, omitting NA/null values,
and places the result in the same locations as the non-NA values.
Parameters
----------
axis : int
Has no effect but is accepted for compatibility with numpy.
kind : {'mergesort', 'quicksort', 'heapsort'}, default 'quicksort'
Choice of sorting algorithm. See np.sort for more
information. 'mergesort' is the only stable algorithm
order : None
Has no effect but is accepted for compatibility with numpy.
Returns
-------
Series
Positions of values within the sort order with -1 indicating
nan values.
See Also
--------
numpy.ndarray.argsort
"""
values = self._values
mask = isna(values)
if mask.any():
result = Series(-1, index=self.index, name=self.name, dtype="int64")
notmask = ~mask
result[notmask] = np.argsort(values[notmask], kind=kind)
return self._constructor(result, index=self.index).__finalize__(self)
else:
return self._constructor(
np.argsort(values, kind=kind), index=self.index, dtype="int64"
).__finalize__(self)
def nlargest(self, n=5, keep="first"):
"""
Return the largest `n` elements.
Parameters
----------
n : int, default 5
Return this many descending sorted values.
keep : {'first', 'last', 'all'}, default 'first'
When there are duplicate values that cannot all fit in a
Series of `n` elements:
- ``first`` : return the first `n` occurrences in order
of appearance.
- ``last`` : return the last `n` occurrences in reverse
order of appearance.
- ``all`` : keep all occurrences. This can result in a Series of
size larger than `n`.
Returns
-------
Series
The `n` largest values in the Series, sorted in decreasing order.
See Also
--------
Series.nsmallest: Get the `n` smallest elements.
Series.sort_values: Sort Series by values.
Series.head: Return the first `n` rows.
Notes
-----
Faster than ``.sort_values(ascending=False).head(n)`` for small `n`
relative to the size of the ``Series`` object.
Examples
--------
>>> countries_population = {"Italy": 59000000, "France": 65000000,
... "Malta": 434000, "Maldives": 434000,
... "Brunei": 434000, "Iceland": 337000,
... "Nauru": 11300, "Tuvalu": 11300,
... "Anguilla": 11300, "Monserat": 5200}
>>> s = pd.Series(countries_population)
>>> s
Italy 59000000
France 65000000
Malta 434000
Maldives 434000
Brunei 434000
Iceland 337000
Nauru 11300
Tuvalu 11300
Anguilla 11300
Monserat 5200
dtype: int64
The `n` largest elements where ``n=5`` by default.
>>> s.nlargest()
France 65000000
Italy 59000000
Malta 434000
Maldives 434000
Brunei 434000
dtype: int64
The `n` largest elements where ``n=3``. Default `keep` value is 'first'
so Malta will be kept.
>>> s.nlargest(3)
France 65000000
Italy 59000000
Malta 434000
dtype: int64
The `n` largest elements where ``n=3`` and keeping the last duplicates.
Brunei will be kept since it is the last with value 434000 based on
the index order.
>>> s.nlargest(3, keep='last')
France 65000000
Italy 59000000
Brunei 434000
dtype: int64
The `n` largest elements where ``n=3`` with all duplicates kept. Note
that the returned Series has five elements due to the three duplicates.
>>> s.nlargest(3, keep='all')
France 65000000
Italy 59000000
Malta 434000
Maldives 434000
Brunei 434000
dtype: int64
"""
return algorithms.SelectNSeries(self, n=n, keep=keep).nlargest()
def nsmallest(self, n=5, keep="first"):
"""
Return the smallest `n` elements.
Parameters
----------
n : int, default 5
Return this many ascending sorted values.
keep : {'first', 'last', 'all'}, default 'first'
When there are duplicate values that cannot all fit in a
Series of `n` elements:
- ``first`` : return the first `n` occurrences in order
of appearance.
- ``last`` : return the last `n` occurrences in reverse
order of appearance.
- ``all`` : keep all occurrences. This can result in a Series of
size larger than `n`.
Returns
-------
Series
The `n` smallest values in the Series, sorted in increasing order.
See Also
--------
Series.nlargest: Get the `n` largest elements.
Series.sort_values: Sort Series by values.
Series.head: Return the first `n` rows.
Notes
-----
Faster than ``.sort_values().head(n)`` for small `n` relative to
the size of the ``Series`` object.
Examples
--------
>>> countries_population = {"Italy": 59000000, "France": 65000000,
... "Brunei": 434000, "Malta": 434000,
... "Maldives": 434000, "Iceland": 337000,
... "Nauru": 11300, "Tuvalu": 11300,
... "Anguilla": 11300, "Monserat": 5200}
>>> s = pd.Series(countries_population)
>>> s
Italy 59000000
France 65000000
Brunei 434000
Malta 434000
Maldives 434000
Iceland 337000
Nauru 11300
Tuvalu 11300
Anguilla 11300
Monserat 5200
dtype: int64
The `n` smallest elements where ``n=5`` by default.
>>> s.nsmallest()
Monserat 5200
Nauru 11300
Tuvalu 11300
Anguilla 11300
Iceland 337000
dtype: int64
The `n` smallest elements where ``n=3``. Default `keep` value is
'first' so Nauru and Tuvalu will be kept.
>>> s.nsmallest(3)
Monserat 5200
Nauru 11300
Tuvalu 11300
dtype: int64
The `n` smallest elements where ``n=3`` and keeping the last
duplicates. Anguilla and Tuvalu will be kept since they are the last
with value 11300 based on the index order.
>>> s.nsmallest(3, keep='last')
Monserat 5200
Anguilla 11300
Tuvalu 11300
dtype: int64
The `n` smallest elements where ``n=3`` with all duplicates kept. Note
that the returned Series has four elements due to the three duplicates.
>>> s.nsmallest(3, keep='all')
Monserat 5200
Nauru 11300
Tuvalu 11300
Anguilla 11300
dtype: int64
"""
return algorithms.SelectNSeries(self, n=n, keep=keep).nsmallest()
def swaplevel(self, i=-2, j=-1, copy=True):
"""
Swap levels i and j in a :class:`MultiIndex`.
Default is to swap the two innermost levels of the index.
Parameters
----------
i, j : int, str (can be mixed)
Level of index to be swapped. Can pass level name as string.
copy : bool, default True
Whether to copy underlying data.
Returns
-------
Series
Series with levels swapped in MultiIndex.
"""
new_index = self.index.swaplevel(i, j)
return self._constructor(self._values, index=new_index, copy=copy).__finalize__(
self
)
def reorder_levels(self, order):
"""
Rearrange index levels using input order.
May not drop or duplicate levels.
Parameters
----------
order : list of int representing new level order
(reference level by number or key)
Returns
-------
type of caller (new object)
"""
if not isinstance(self.index, MultiIndex): # pragma: no cover
raise Exception("Can only reorder levels on a hierarchical axis.")
result = self.copy()
result.index = result.index.reorder_levels(order)
return result
def explode(self) -> "Series":
"""
Transform each element of a list-like to a row, replicating the
index values.
.. versionadded:: 0.25.0
Returns
-------
Series
Exploded lists to rows; index will be duplicated for these rows.
See Also
--------
Series.str.split : Split string values on specified separator.
Series.unstack : Unstack, a.k.a. pivot, Series with MultiIndex
to produce DataFrame.
DataFrame.melt : Unpivot a DataFrame from wide format to long format.
DataFrame.explode : Explode a DataFrame from list-like
columns to long format.
Notes
-----
This routine will explode list-likes including lists, tuples,
Series, and np.ndarray. The result dtype of the subset rows will
be object. Scalars will be returned unchanged. Empty list-likes will
result in a np.nan for that row.
Examples
--------
>>> s = pd.Series([[1, 2, 3], 'foo', [], [3, 4]])
>>> s
0 [1, 2, 3]
1 foo
2 []
3 [3, 4]
dtype: object
>>> s.explode()
0 1
0 2
0 3
1 foo
2 NaN
3 3
3 4
dtype: object
"""
if not len(self) or not is_object_dtype(self):
return self.copy()
values, counts = reshape.explode(np.asarray(self.array))
result = Series(values, index=self.index.repeat(counts), name=self.name)
return result
def unstack(self, level=-1, fill_value=None):
"""
Unstack, a.k.a. pivot, Series with MultiIndex to produce DataFrame.
The level involved will automatically get sorted.
Parameters
----------
level : int, str, or list of these, default last level
Level(s) to unstack, can pass level name.
fill_value : scalar value, default None
Value to use when replacing NaN values.
Returns
-------
DataFrame
Unstacked Series.
Examples
--------
>>> s = pd.Series([1, 2, 3, 4],
... index=pd.MultiIndex.from_product([['one', 'two'],
... ['a', 'b']]))
>>> s
one a 1
b 2
two a 3
b 4
dtype: int64
>>> s.unstack(level=-1)
a b
one 1 2
two 3 4
>>> s.unstack(level=0)
one two
a 1 3
b 2 4
"""
from pandas.core.reshape.reshape import unstack
return unstack(self, level, fill_value)
# ----------------------------------------------------------------------
# function application
def map(self, arg, na_action=None):
"""
Map values of Series according to input correspondence.
Used for substituting each value in a Series with another value,
that may be derived from a function, a ``dict`` or
a :class:`Series`.
Parameters
----------
arg : function, dict, or Series
Mapping correspondence.
na_action : {None, 'ignore'}, default None
If 'ignore', propagate NaN values, without passing them to the
mapping correspondence.
Returns
-------
Series
Same index as caller.
See Also
--------
Series.apply : For applying more complex functions on a Series.
DataFrame.apply : Apply a function row-/column-wise.
DataFrame.applymap : Apply a function elementwise on a whole DataFrame.
Notes
-----
When ``arg`` is a dictionary, values in Series that are not in the
dictionary (as keys) are converted to ``NaN``. However, if the
dictionary is a ``dict`` subclass that defines ``__missing__`` (i.e.
provides a method for default values), then this default is used
rather than ``NaN``.
Examples
--------
>>> s = pd.Series(['cat', 'dog', np.nan, 'rabbit'])
>>> s
0 cat
1 dog
2 NaN
3 rabbit
dtype: object
``map`` accepts a ``dict`` or a ``Series``. Values that are not found
in the ``dict`` are converted to ``NaN``, unless the dict has a default
value (e.g. ``defaultdict``):
>>> s.map({'cat': 'kitten', 'dog': 'puppy'})
0 kitten
1 puppy
2 NaN
3 NaN
dtype: object
It also accepts a function:
>>> s.map('I am a {}'.format)
0 I am a cat
1 I am a dog
2 I am a nan
3 I am a rabbit
dtype: object
To avoid applying the function to missing values (and keep them as
``NaN``) ``na_action='ignore'`` can be used:
>>> s.map('I am a {}'.format, na_action='ignore')
0 I am a cat
1 I am a dog
2 NaN
3 I am a rabbit
dtype: object
"""
new_values = super()._map_values(arg, na_action=na_action)
return self._constructor(new_values, index=self.index).__finalize__(self)
def _gotitem(self, key, ndim, subset=None):
"""
Sub-classes to define. Return a sliced object.
Parameters
----------
key : string / list of selections
ndim : 1,2
requested ndim of result
subset : object, default None
subset to act on
"""
return self
_agg_see_also_doc = dedent(
"""
See Also
--------
Series.apply : Invoke function on a Series.
Series.transform : Transform function producing a Series with like indexes.
"""
)
_agg_examples_doc = dedent(
"""
Examples
--------
>>> s = pd.Series([1, 2, 3, 4])
>>> s
0 1
1 2
2 3
3 4
dtype: int64
>>> s.agg('min')
1
>>> s.agg(['min', 'max'])
min 1
max 4
dtype: int64
"""
)
@Substitution(
see_also=_agg_see_also_doc,
examples=_agg_examples_doc,
versionadded="\n.. versionadded:: 0.20.0\n",
**_shared_doc_kwargs
)
@Appender(generic._shared_docs["aggregate"])
def aggregate(self, func, axis=0, *args, **kwargs):
# Validate the axis parameter
self._get_axis_number(axis)
result, how = self._aggregate(func, *args, **kwargs)
if result is None:
# we can be called from an inner function which
# passes this meta-data
kwargs.pop("_axis", None)
kwargs.pop("_level", None)
# try a regular apply, this evaluates lambdas
# row-by-row; however if the lambda is expected a Series
# expression, e.g.: lambda x: x-x.quantile(0.25)
# this will fail, so we can try a vectorized evaluation
# we cannot FIRST try the vectorized evaluation, because
# then .agg and .apply would have different semantics if the
# operation is actually defined on the Series, e.g. str
try:
result = self.apply(func, *args, **kwargs)
except (ValueError, AttributeError, TypeError):
result = func(self, *args, **kwargs)
return result
agg = aggregate
@Appender(generic._shared_docs["transform"] % _shared_doc_kwargs)
def transform(self, func, axis=0, *args, **kwargs):
# Validate the axis parameter
self._get_axis_number(axis)
return super().transform(func, *args, **kwargs)
def apply(self, func, convert_dtype=True, args=(), **kwds):
"""
Invoke function on values of Series.
Can be ufunc (a NumPy function that applies to the entire Series)
or a Python function that only works on single values.
Parameters
----------
func : function
Python function or NumPy ufunc to apply.
convert_dtype : bool, default True
Try to find better dtype for elementwise function results. If
False, leave as dtype=object.
args : tuple
Positional arguments passed to func after the series value.
**kwds
Additional keyword arguments passed to func.
Returns
-------
Series or DataFrame
If func returns a Series object the result will be a DataFrame.
See Also
--------
Series.map: For element-wise operations.
Series.agg: Only perform aggregating type operations.
Series.transform: Only perform transforming type operations.
Examples
--------
Create a series with typical summer temperatures for each city.
>>> s = pd.Series([20, 21, 12],
... index=['London', 'New York', 'Helsinki'])
>>> s
London 20
New York 21
Helsinki 12
dtype: int64
Square the values by defining a function and passing it as an
argument to ``apply()``.
>>> def square(x):
... return x ** 2
>>> s.apply(square)
London 400
New York 441
Helsinki 144
dtype: int64
Square the values by passing an anonymous function as an
argument to ``apply()``.
>>> s.apply(lambda x: x ** 2)
London 400
New York 441
Helsinki 144
dtype: int64
Define a custom function that needs additional positional
arguments and pass these additional arguments using the
``args`` keyword.
>>> def subtract_custom_value(x, custom_value):
... return x - custom_value
>>> s.apply(subtract_custom_value, args=(5,))
London 15
New York 16
Helsinki 7
dtype: int64
Define a custom function that takes keyword arguments
and pass these arguments to ``apply``.
>>> def add_custom_values(x, **kwargs):
... for month in kwargs:
... x += kwargs[month]
... return x
>>> s.apply(add_custom_values, june=30, july=20, august=25)
London 95
New York 96
Helsinki 87
dtype: int64
Use a function from the Numpy library.
>>> s.apply(np.log)
London 2.995732
New York 3.044522
Helsinki 2.484907
dtype: float64
"""
if len(self) == 0:
return self._constructor(dtype=self.dtype, index=self.index).__finalize__(
self
)
# dispatch to agg
if isinstance(func, (list, dict)):
return self.aggregate(func, *args, **kwds)
# if we are a string, try to dispatch
if isinstance(func, str):
return self._try_aggregate_string_function(func, *args, **kwds)
# handle ufuncs and lambdas
if kwds or args and not isinstance(func, np.ufunc):
def f(x):
return func(x, *args, **kwds)
else:
f = func
with np.errstate(all="ignore"):
if isinstance(f, np.ufunc):
return f(self)
# row-wise access
if is_extension_type(self.dtype):
mapped = self._values.map(f)
else:
values = self.astype(object).values
mapped = lib.map_infer(values, f, convert=convert_dtype)
if len(mapped) and isinstance(mapped[0], Series):
# GH 25959 use pd.array instead of tolist
# so extension arrays can be used
return self._constructor_expanddim(pd.array(mapped), index=self.index)
else:
return self._constructor(mapped, index=self.index).__finalize__(self)
def _reduce(
self, op, name, axis=0, skipna=True, numeric_only=None, filter_type=None, **kwds
):
"""
Perform a reduction operation.
If we have an ndarray as a value, then simply perform the operation,
otherwise delegate to the object.
"""
delegate = self._values
if axis is not None:
self._get_axis_number(axis)
if isinstance(delegate, Categorical):
# TODO deprecate numeric_only argument for Categorical and use
# skipna as well, see GH25303
return delegate._reduce(name, numeric_only=numeric_only, **kwds)
elif isinstance(delegate, ExtensionArray):
# dispatch to ExtensionArray interface
return delegate._reduce(name, skipna=skipna, **kwds)
elif is_datetime64_dtype(delegate):
# use DatetimeIndex implementation to handle skipna correctly
delegate = DatetimeIndex(delegate)
elif is_timedelta64_dtype(delegate) and hasattr(TimedeltaIndex, name):
# use TimedeltaIndex to handle skipna correctly
# TODO: remove hasattr check after TimedeltaIndex has `std` method
delegate = TimedeltaIndex(delegate)
# dispatch to numpy arrays
elif isinstance(delegate, np.ndarray):
if numeric_only:
raise NotImplementedError(
"Series.{0} does not implement numeric_only.".format(name)
)
with np.errstate(all="ignore"):
return op(delegate, skipna=skipna, **kwds)
# TODO(EA) dispatch to Index
# remove once all internals extension types are
# moved to ExtensionArrays
return delegate._reduce(
op=op,
name=name,
axis=axis,
skipna=skipna,
numeric_only=numeric_only,
filter_type=filter_type,
**kwds
)
def _reindex_indexer(self, new_index, indexer, copy):
if indexer is None:
if copy:
return self.copy()
return self
new_values = algorithms.take_1d(
self._values, indexer, allow_fill=True, fill_value=None
)
return self._constructor(new_values, index=new_index)
def _needs_reindex_multi(self, axes, method, level):
"""
Check if we do need a multi reindex; this is for compat with
higher dims.
"""
return False
@Appender(generic._shared_docs["align"] % _shared_doc_kwargs)
def align(
self,
other,
join="outer",
axis=None,
level=None,
copy=True,
fill_value=None,
method=None,
limit=None,
fill_axis=0,
broadcast_axis=None,
):
return super().align(
other,
join=join,
axis=axis,
level=level,
copy=copy,
fill_value=fill_value,
method=method,
limit=limit,
fill_axis=fill_axis,
broadcast_axis=broadcast_axis,
)
def rename(self, index=None, **kwargs):
"""
Alter Series index labels or name.
Function / dict values must be unique (1-to-1). Labels not contained in
a dict / Series will be left as-is. Extra labels listed don't throw an
error.
Alternatively, change ``Series.name`` with a scalar value.
See the :ref:`user guide <basics.rename>` for more.
Parameters
----------
index : scalar, hashable sequence, dict-like or function, optional
dict-like or functions are transformations to apply to
the index.
Scalar or hashable sequence-like will alter the ``Series.name``
attribute.
copy : bool, default True
Whether to copy underlying data.
inplace : bool, default False
Whether to return a new Series. If True then value of copy is
ignored.
level : int or level name, default None
In case of a MultiIndex, only rename labels in the specified
level.
Returns
-------
Series
Series with index labels or name altered.
See Also
--------
Series.rename_axis : Set the name of the axis.
Examples
--------
>>> s = pd.Series([1, 2, 3])
>>> s
0 1
1 2
2 3
dtype: int64
>>> s.rename("my_name") # scalar, changes Series.name
0 1
1 2
2 3
Name: my_name, dtype: int64
>>> s.rename(lambda x: x ** 2) # function, changes labels
0 1
1 2
4 3
dtype: int64
>>> s.rename({1: 3, 2: 5}) # mapping, changes labels
0 1
3 2
5 3
dtype: int64
"""
kwargs["inplace"] = validate_bool_kwarg(kwargs.get("inplace", False), "inplace")
if callable(index) or is_dict_like(index):
return super().rename(index=index, **kwargs)
else:
return self._set_name(index, inplace=kwargs.get("inplace"))
@Substitution(**_shared_doc_kwargs)
@Appender(generic.NDFrame.reindex.__doc__)
def reindex(self, index=None, **kwargs):
return super().reindex(index=index, **kwargs)
def drop(
self,
labels=None,
axis=0,
index=None,
columns=None,
level=None,
inplace=False,
errors="raise",
):
"""
Return Series with specified index labels removed.
Remove elements of a Series based on specifying the index labels.
When using a multi-index, labels on different levels can be removed
by specifying the level.
Parameters
----------
labels : single label or list-like
Index labels to drop.
axis : 0, default 0
Redundant for application on Series.
index, columns : None
Redundant for application on Series, but index can be used instead
of labels.
.. versionadded:: 0.21.0
level : int or level name, optional
For MultiIndex, level for which the labels will be removed.
inplace : bool, default False
If True, do operation inplace and return None.
errors : {'ignore', 'raise'}, default 'raise'
If 'ignore', suppress error and only existing labels are dropped.
Returns
-------
Series
Series with specified index labels removed.
Raises
------
KeyError
If none of the labels are found in the index.
See Also
--------
Series.reindex : Return only specified index labels of Series.
Series.dropna : Return series without null values.
Series.drop_duplicates : Return Series with duplicate values removed.
DataFrame.drop : Drop specified labels from rows or columns.
Examples
--------
>>> s = pd.Series(data=np.arange(3), index=['A', 'B', 'C'])
>>> s
A 0
B 1
C 2
dtype: int64
Drop labels B en C
>>> s.drop(labels=['B', 'C'])
A 0
dtype: int64
Drop 2nd level label in MultiIndex Series
>>> midx = pd.MultiIndex(levels=[['lama', 'cow', 'falcon'],
... ['speed', 'weight', 'length']],
... codes=[[0, 0, 0, 1, 1, 1, 2, 2, 2],
... [0, 1, 2, 0, 1, 2, 0, 1, 2]])
>>> s = pd.Series([45, 200, 1.2, 30, 250, 1.5, 320, 1, 0.3],
... index=midx)
>>> s
lama speed 45.0
weight 200.0
length 1.2
cow speed 30.0
weight 250.0
length 1.5
falcon speed 320.0
weight 1.0
length 0.3
dtype: float64
>>> s.drop(labels='weight', level=1)
lama speed 45.0
length 1.2
cow speed 30.0
length 1.5
falcon speed 320.0
length 0.3
dtype: float64
"""
return super().drop(
labels=labels,
axis=axis,
index=index,
columns=columns,
level=level,
inplace=inplace,
errors=errors,
)
@Substitution(**_shared_doc_kwargs)
@Appender(generic.NDFrame.fillna.__doc__)
def fillna(
self,
value=None,
method=None,
axis=None,
inplace=False,
limit=None,
downcast=None,
**kwargs
):
return super().fillna(
value=value,
method=method,
axis=axis,
inplace=inplace,
limit=limit,
downcast=downcast,
**kwargs
)
@Appender(generic._shared_docs["replace"] % _shared_doc_kwargs)
def replace(
self,
to_replace=None,
value=None,
inplace=False,
limit=None,
regex=False,
method="pad",
):
return super().replace(
to_replace=to_replace,
value=value,
inplace=inplace,
limit=limit,
regex=regex,
method=method,
)
@Appender(generic._shared_docs["shift"] % _shared_doc_kwargs)
def shift(self, periods=1, freq=None, axis=0, fill_value=None):
return super().shift(
periods=periods, freq=freq, axis=axis, fill_value=fill_value
)
def memory_usage(self, index=True, deep=False):
"""
Return the memory usage of the Series.
The memory usage can optionally include the contribution of
the index and of elements of `object` dtype.
Parameters
----------
index : bool, default True
Specifies whether to include the memory usage of the Series index.
deep : bool, default False
If True, introspect the data deeply by interrogating
`object` dtypes for system-level memory consumption, and include
it in the returned value.
Returns
-------
int
Bytes of memory consumed.
See Also
--------
numpy.ndarray.nbytes : Total bytes consumed by the elements of the
array.
DataFrame.memory_usage : Bytes consumed by a DataFrame.
Examples
--------
>>> s = pd.Series(range(3))
>>> s.memory_usage()
152
Not including the index gives the size of the rest of the data, which
is necessarily smaller:
>>> s.memory_usage(index=False)
24
The memory footprint of `object` values is ignored by default:
>>> s = pd.Series(["a", "b"])
>>> s.values
array(['a', 'b'], dtype=object)
>>> s.memory_usage()
144
>>> s.memory_usage(deep=True)
260
"""
v = super().memory_usage(deep=deep)
if index:
v += self.index.memory_usage(deep=deep)
return v
def isin(self, values):
"""
Check whether `values` are contained in Series.
Return a boolean Series showing whether each element in the Series
matches an element in the passed sequence of `values` exactly.
Parameters
----------
values : set or list-like
The sequence of values to test. Passing in a single string will
raise a ``TypeError``. Instead, turn a single string into a
list of one element.
Returns
-------
Series
Series of booleans indicating if each element is in values.
Raises
------
TypeError
* If `values` is a string
See Also
--------
DataFrame.isin : Equivalent method on DataFrame.
Examples
--------
>>> s = pd.Series(['lama', 'cow', 'lama', 'beetle', 'lama',
... 'hippo'], name='animal')
>>> s.isin(['cow', 'lama'])
0 True
1 True
2 True
3 False
4 True
5 False
Name: animal, dtype: bool
Passing a single string as ``s.isin('lama')`` will raise an error. Use
a list of one element instead:
>>> s.isin(['lama'])
0 True
1 False
2 True
3 False
4 True
5 False
Name: animal, dtype: bool
"""
result = algorithms.isin(self, values)
return self._constructor(result, index=self.index).__finalize__(self)
def between(self, left, right, inclusive=True):
"""
Return boolean Series equivalent to left <= series <= right.
This function returns a boolean vector containing `True` wherever the
corresponding Series element is between the boundary values `left` and
`right`. NA values are treated as `False`.
Parameters
----------
left : scalar
Left boundary.
right : scalar
Right boundary.
inclusive : bool, default True
Include boundaries.
Returns
-------
Series
Series representing whether each element is between left and
right (inclusive).
See Also
--------
Series.gt : Greater than of series and other.
Series.lt : Less than of series and other.
Notes
-----
This function is equivalent to ``(left <= ser) & (ser <= right)``
Examples
--------
>>> s = pd.Series([2, 0, 4, 8, np.nan])
Boundary values are included by default:
>>> s.between(1, 4)
0 True
1 False
2 True
3 False
4 False
dtype: bool
With `inclusive` set to ``False`` boundary values are excluded:
>>> s.between(1, 4, inclusive=False)
0 True
1 False
2 False
3 False
4 False
dtype: bool
`left` and `right` can be any scalar value:
>>> s = pd.Series(['Alice', 'Bob', 'Carol', 'Eve'])
>>> s.between('Anna', 'Daniel')
0 False
1 True
2 True
3 False
dtype: bool
"""
if inclusive:
lmask = self >= left
rmask = self <= right
else:
lmask = self > left
rmask = self < right
return lmask & rmask
@Appender(generic.NDFrame.to_csv.__doc__)
def to_csv(self, *args, **kwargs):
names = [
"path_or_buf",
"sep",
"na_rep",
"float_format",
"columns",
"header",
"index",
"index_label",
"mode",
"encoding",
"compression",
"quoting",
"quotechar",
"line_terminator",
"chunksize",
"date_format",
"doublequote",
"escapechar",
"decimal",
]
old_names = [
"path_or_buf",
"index",
"sep",
"na_rep",
"float_format",
"header",
"index_label",
"mode",
"encoding",
"compression",
"date_format",
"decimal",
]
if "path" in kwargs:
warnings.warn(
"The signature of `Series.to_csv` was aligned "
"to that of `DataFrame.to_csv`, and argument "
"'path' will be renamed to 'path_or_buf'.",
FutureWarning,
stacklevel=2,
)
kwargs["path_or_buf"] = kwargs.pop("path")
if len(args) > 1:
# Either "index" (old signature) or "sep" (new signature) is being
# passed as second argument (while the first is the same)
maybe_sep = args[1]
if not (is_string_like(maybe_sep) and len(maybe_sep) == 1):
# old signature
warnings.warn(
"The signature of `Series.to_csv` was aligned "
"to that of `DataFrame.to_csv`. Note that the "
"order of arguments changed, and the new one "
"has 'sep' in first place, for which \"{}\" is "
"not a valid value. The old order will cease to "
"be supported in a future version. Please refer "
"to the documentation for `DataFrame.to_csv` "
"when updating your function "
"calls.".format(maybe_sep),
FutureWarning,
stacklevel=2,
)
names = old_names
pos_args = dict(zip(names[: len(args)], args))
for key in pos_args:
if key in kwargs:
raise ValueError(
"Argument given by name ('{}') and position "
"({})".format(key, names.index(key))
)
kwargs[key] = pos_args[key]
if kwargs.get("header", None) is None:
warnings.warn(
"The signature of `Series.to_csv` was aligned "
"to that of `DataFrame.to_csv`, and argument "
"'header' will change its default value from False "
"to True: please pass an explicit value to suppress "
"this warning.",
FutureWarning,
stacklevel=2,
)
kwargs["header"] = False # Backwards compatibility.
return self.to_frame().to_csv(**kwargs)
@Appender(generic._shared_docs["isna"] % _shared_doc_kwargs)
def isna(self):
return super().isna()
@Appender(generic._shared_docs["isna"] % _shared_doc_kwargs)
def isnull(self):
return super().isnull()
@Appender(generic._shared_docs["notna"] % _shared_doc_kwargs)
def notna(self):
return super().notna()
@Appender(generic._shared_docs["notna"] % _shared_doc_kwargs)
def notnull(self):
return super().notnull()
def dropna(self, axis=0, inplace=False, **kwargs):
"""
Return a new Series with missing values removed.
See the :ref:`User Guide <missing_data>` for more on which values are
considered missing, and how to work with missing data.
Parameters
----------
axis : {0 or 'index'}, default 0
There is only one axis to drop values from.
inplace : bool, default False
If True, do operation inplace and return None.
**kwargs
Not in use.
Returns
-------
Series
Series with NA entries dropped from it.
See Also
--------
Series.isna: Indicate missing values.
Series.notna : Indicate existing (non-missing) values.
Series.fillna : Replace missing values.
DataFrame.dropna : Drop rows or columns which contain NA values.
Index.dropna : Drop missing indices.
Examples
--------
>>> ser = pd.Series([1., 2., np.nan])
>>> ser
0 1.0
1 2.0
2 NaN
dtype: float64
Drop NA values from a Series.
>>> ser.dropna()
0 1.0
1 2.0
dtype: float64
Keep the Series with valid entries in the same variable.
>>> ser.dropna(inplace=True)
>>> ser
0 1.0
1 2.0
dtype: float64
Empty strings are not considered NA values. ``None`` is considered an
NA value.
>>> ser = pd.Series([np.NaN, 2, pd.NaT, '', None, 'I stay'])
>>> ser
0 NaN
1 2
2 NaT
3
4 None
5 I stay
dtype: object
>>> ser.dropna()
1 2
3
5 I stay
dtype: object
"""
inplace = validate_bool_kwarg(inplace, "inplace")
kwargs.pop("how", None)
if kwargs:
raise TypeError(
"dropna() got an unexpected keyword "
'argument "{0}"'.format(list(kwargs.keys())[0])
)
# Validate the axis parameter
self._get_axis_number(axis or 0)
if self._can_hold_na:
result = remove_na_arraylike(self)
if inplace:
self._update_inplace(result)
else:
return result
else:
if inplace:
# do nothing
pass
else:
return self.copy()
def valid(self, inplace=False, **kwargs):
"""
Return Series without null values.
.. deprecated:: 0.23.0
Use :meth:`Series.dropna` instead.
Returns
-------
Series
Series without null values.
"""
warnings.warn(
"Method .valid will be removed in a future version. "
"Use .dropna instead.",
FutureWarning,
stacklevel=2,
)
return self.dropna(inplace=inplace, **kwargs)
# ----------------------------------------------------------------------
# Time series-oriented methods
def to_timestamp(self, freq=None, how="start", copy=True):
"""
Cast to DatetimeIndex of Timestamps, at *beginning* of period.
Parameters
----------
freq : str, default frequency of PeriodIndex
Desired frequency.
how : {'s', 'e', 'start', 'end'}
Convention for converting period to timestamp; start of period
vs. end.
copy : bool, default True
Whether or not to return a copy.
Returns
-------
Series with DatetimeIndex
"""
new_values = self._values
if copy:
new_values = new_values.copy()
new_index = self.index.to_timestamp(freq=freq, how=how)
return self._constructor(new_values, index=new_index).__finalize__(self)
def to_period(self, freq=None, copy=True):
"""
Convert Series from DatetimeIndex to PeriodIndex with desired
frequency (inferred from index if not passed).
Parameters
----------
freq : str, default None
Frequency associated with the PeriodIndex.
copy : bool, default True
Whether or not to return a copy.
Returns
-------
Series
Series with index converted to PeriodIndex.
"""
new_values = self._values
if copy:
new_values = new_values.copy()
new_index = self.index.to_period(freq=freq)
return self._constructor(new_values, index=new_index).__finalize__(self)
# ----------------------------------------------------------------------
# Accessor Methods
# ----------------------------------------------------------------------
str = CachedAccessor("str", StringMethods)
dt = CachedAccessor("dt", CombinedDatetimelikeProperties)
cat = CachedAccessor("cat", CategoricalAccessor)
plot = CachedAccessor("plot", pandas.plotting.PlotAccessor)
sparse = CachedAccessor("sparse", SparseAccessor)
# ----------------------------------------------------------------------
# Add plotting methods to Series
hist = pandas.plotting.hist_series
Series._setup_axes(
["index"],
info_axis=0,
stat_axis=0,
aliases={"rows": 0},
docs={"index": "The index (axis labels) of the Series."},
)
Series._add_numeric_operations()
Series._add_series_only_operations()
Series._add_series_or_dataframe_operations()
# Add arithmetic!
ops.add_flex_arithmetic_methods(Series)
ops.add_special_arithmetic_methods(Series)
| BugsInPy/BugsInPy/temp/projects/pandas/bug-152-fixed/pandas/pandas/core/series.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-152-buggy/pandas/pandas/core/series.py |
pandas-bug-37 | import operator
from typing import TYPE_CHECKING, Type, Union
import numpy as np
from pandas._libs import lib, missing as libmissing
from pandas.core.dtypes.base import ExtensionDtype
from pandas.core.dtypes.common import pandas_dtype
from pandas.core.dtypes.dtypes import register_extension_dtype
from pandas.core.dtypes.generic import ABCDataFrame, ABCIndexClass, ABCSeries
from pandas.core.dtypes.inference import is_array_like
from pandas import compat
from pandas.core import ops
from pandas.core.arrays import PandasArray
from pandas.core.construction import extract_array
from pandas.core.indexers import check_array_indexer
from pandas.core.missing import isna
if TYPE_CHECKING:
import pyarrow # noqa: F401
@register_extension_dtype
class StringDtype(ExtensionDtype):
"""
Extension dtype for string data.
.. versionadded:: 1.0.0
.. warning::
StringDtype is considered experimental. The implementation and
parts of the API may change without warning.
In particular, StringDtype.na_value may change to no longer be
``numpy.nan``.
Attributes
----------
None
Methods
-------
None
Examples
--------
>>> pd.StringDtype()
StringDtype
"""
name = "string"
#: StringDtype.na_value uses pandas.NA
na_value = libmissing.NA
@property
def type(self) -> Type[str]:
return str
@classmethod
def construct_array_type(cls) -> Type["StringArray"]:
"""
Return the array type associated with this dtype.
Returns
-------
type
"""
return StringArray
def __repr__(self) -> str:
return "StringDtype"
def __from_arrow__(
self, array: Union["pyarrow.Array", "pyarrow.ChunkedArray"]
) -> "StringArray":
"""
Construct StringArray from pyarrow Array/ChunkedArray.
"""
import pyarrow # noqa: F811
if isinstance(array, pyarrow.Array):
chunks = [array]
else:
# pyarrow.ChunkedArray
chunks = array.chunks
results = []
for arr in chunks:
# using _from_sequence to ensure None is converted to NA
str_arr = StringArray._from_sequence(np.array(arr))
results.append(str_arr)
return StringArray._concat_same_type(results)
class StringArray(PandasArray):
"""
Extension array for string data.
.. versionadded:: 1.0.0
.. warning::
StringArray is considered experimental. The implementation and
parts of the API may change without warning.
Parameters
----------
values : array-like
The array of data.
.. warning::
Currently, this expects an object-dtype ndarray
where the elements are Python strings or :attr:`pandas.NA`.
This may change without warning in the future. Use
:meth:`pandas.array` with ``dtype="string"`` for a stable way of
creating a `StringArray` from any sequence.
copy : bool, default False
Whether to copy the array of data.
Attributes
----------
None
Methods
-------
None
See Also
--------
array
The recommended function for creating a StringArray.
Series.str
The string methods are available on Series backed by
a StringArray.
Notes
-----
StringArray returns a BooleanArray for comparison methods.
Examples
--------
>>> pd.array(['This is', 'some text', None, 'data.'], dtype="string")
<StringArray>
['This is', 'some text', <NA>, 'data.']
Length: 4, dtype: string
Unlike ``object`` dtype arrays, ``StringArray`` doesn't allow non-string
values.
>>> pd.array(['1', 1], dtype="string")
Traceback (most recent call last):
...
ValueError: StringArray requires an object-dtype ndarray of strings.
For comparison methods, this returns a :class:`pandas.BooleanArray`
>>> pd.array(["a", None, "c"], dtype="string") == "a"
<BooleanArray>
[True, <NA>, False]
Length: 3, dtype: boolean
"""
# undo the PandasArray hack
_typ = "extension"
def __init__(self, values, copy=False):
values = extract_array(values)
skip_validation = isinstance(values, type(self))
super().__init__(values, copy=copy)
self._dtype = StringDtype()
if not skip_validation:
self._validate()
def _validate(self):
"""Validate that we only store NA or strings."""
if len(self._ndarray) and not lib.is_string_array(self._ndarray, skipna=True):
raise ValueError("StringArray requires a sequence of strings or pandas.NA")
if self._ndarray.dtype != "object":
raise ValueError(
"StringArray requires a sequence of strings or pandas.NA. Got "
f"'{self._ndarray.dtype}' dtype instead."
)
@classmethod
def _from_sequence(cls, scalars, dtype=None, copy=False):
if dtype:
assert dtype == "string"
result = np.asarray(scalars, dtype="object")
if copy and result is scalars:
result = result.copy()
# Standardize all missing-like values to NA
# TODO: it would be nice to do this in _validate / lib.is_string_array
# We are already doing a scan over the values there.
na_values = isna(result)
if na_values.any():
if result is scalars:
# force a copy now, if we haven't already
result = result.copy()
result[na_values] = StringDtype.na_value
return cls(result)
@classmethod
def _from_sequence_of_strings(cls, strings, dtype=None, copy=False):
return cls._from_sequence(strings, dtype=dtype, copy=copy)
def __arrow_array__(self, type=None):
"""
Convert myself into a pyarrow Array.
"""
import pyarrow as pa
if type is None:
type = pa.string()
values = self._ndarray.copy()
values[self.isna()] = None
return pa.array(values, type=type, from_pandas=True)
def _values_for_factorize(self):
arr = self._ndarray.copy()
mask = self.isna()
arr[mask] = -1
return arr, -1
def __setitem__(self, key, value):
value = extract_array(value, extract_numpy=True)
if isinstance(value, type(self)):
# extract_array doesn't extract PandasArray subclasses
value = value._ndarray
key = check_array_indexer(self, key)
scalar_key = lib.is_scalar(key)
scalar_value = lib.is_scalar(value)
if scalar_key and not scalar_value:
raise ValueError("setting an array element with a sequence.")
# validate new items
if scalar_value:
if isna(value):
value = StringDtype.na_value
elif not isinstance(value, str):
raise ValueError(
f"Cannot set non-string value '{value}' into a StringArray."
)
else:
if not is_array_like(value):
value = np.asarray(value, dtype=object)
if len(value) and not lib.is_string_array(value, skipna=True):
raise ValueError("Must provide strings.")
super().__setitem__(key, value)
def fillna(self, value=None, method=None, limit=None):
# TODO: validate dtype
return super().fillna(value, method, limit)
def astype(self, dtype, copy=True):
dtype = pandas_dtype(dtype)
if isinstance(dtype, StringDtype):
if copy:
return self.copy()
return self
return super().astype(dtype, copy)
def _reduce(self, name, skipna=True, **kwargs):
raise TypeError(f"Cannot perform reduction '{name}' with string dtype")
def value_counts(self, dropna=False):
from pandas import value_counts
return value_counts(self._ndarray, dropna=dropna).astype("Int64")
# Override parent because we have different return types.
@classmethod
def _create_arithmetic_method(cls, op):
# Note: this handles both arithmetic and comparison methods.
def method(self, other):
from pandas.arrays import BooleanArray
assert op.__name__ in ops.ARITHMETIC_BINOPS | ops.COMPARISON_BINOPS
if isinstance(other, (ABCIndexClass, ABCSeries, ABCDataFrame)):
return NotImplemented
elif isinstance(other, cls):
other = other._ndarray
mask = isna(self) | isna(other)
valid = ~mask
if not lib.is_scalar(other):
if len(other) != len(self):
# prevent improper broadcasting when other is 2D
raise ValueError(
f"Lengths of operands do not match: {len(self)} != {len(other)}"
)
other = np.asarray(other)
other = other[valid]
if op.__name__ in ops.ARITHMETIC_BINOPS:
result = np.empty_like(self._ndarray, dtype="object")
result[mask] = StringDtype.na_value
result[valid] = op(self._ndarray[valid], other)
return StringArray(result)
else:
# logical
result = np.zeros(len(self._ndarray), dtype="bool")
result[valid] = op(self._ndarray[valid], other)
return BooleanArray(result, mask)
return compat.set_function_name(method, f"__{op.__name__}__", cls)
@classmethod
def _add_arithmetic_ops(cls):
cls.__add__ = cls._create_arithmetic_method(operator.add)
cls.__radd__ = cls._create_arithmetic_method(ops.radd)
cls.__mul__ = cls._create_arithmetic_method(operator.mul)
cls.__rmul__ = cls._create_arithmetic_method(ops.rmul)
_create_comparison_method = _create_arithmetic_method
StringArray._add_arithmetic_ops()
StringArray._add_comparison_ops()
import operator
from typing import TYPE_CHECKING, Type, Union
import numpy as np
from pandas._libs import lib, missing as libmissing
from pandas.core.dtypes.base import ExtensionDtype
from pandas.core.dtypes.common import pandas_dtype
from pandas.core.dtypes.dtypes import register_extension_dtype
from pandas.core.dtypes.generic import ABCDataFrame, ABCIndexClass, ABCSeries
from pandas.core.dtypes.inference import is_array_like
from pandas import compat
from pandas.core import ops
from pandas.core.arrays import IntegerArray, PandasArray
from pandas.core.arrays.integer import _IntegerDtype
from pandas.core.construction import extract_array
from pandas.core.indexers import check_array_indexer
from pandas.core.missing import isna
if TYPE_CHECKING:
import pyarrow # noqa: F401
@register_extension_dtype
class StringDtype(ExtensionDtype):
"""
Extension dtype for string data.
.. versionadded:: 1.0.0
.. warning::
StringDtype is considered experimental. The implementation and
parts of the API may change without warning.
In particular, StringDtype.na_value may change to no longer be
``numpy.nan``.
Attributes
----------
None
Methods
-------
None
Examples
--------
>>> pd.StringDtype()
StringDtype
"""
name = "string"
#: StringDtype.na_value uses pandas.NA
na_value = libmissing.NA
@property
def type(self) -> Type[str]:
return str
@classmethod
def construct_array_type(cls) -> Type["StringArray"]:
"""
Return the array type associated with this dtype.
Returns
-------
type
"""
return StringArray
def __repr__(self) -> str:
return "StringDtype"
def __from_arrow__(
self, array: Union["pyarrow.Array", "pyarrow.ChunkedArray"]
) -> "StringArray":
"""
Construct StringArray from pyarrow Array/ChunkedArray.
"""
import pyarrow # noqa: F811
if isinstance(array, pyarrow.Array):
chunks = [array]
else:
# pyarrow.ChunkedArray
chunks = array.chunks
results = []
for arr in chunks:
# using _from_sequence to ensure None is converted to NA
str_arr = StringArray._from_sequence(np.array(arr))
results.append(str_arr)
return StringArray._concat_same_type(results)
class StringArray(PandasArray):
"""
Extension array for string data.
.. versionadded:: 1.0.0
.. warning::
StringArray is considered experimental. The implementation and
parts of the API may change without warning.
Parameters
----------
values : array-like
The array of data.
.. warning::
Currently, this expects an object-dtype ndarray
where the elements are Python strings or :attr:`pandas.NA`.
This may change without warning in the future. Use
:meth:`pandas.array` with ``dtype="string"`` for a stable way of
creating a `StringArray` from any sequence.
copy : bool, default False
Whether to copy the array of data.
Attributes
----------
None
Methods
-------
None
See Also
--------
array
The recommended function for creating a StringArray.
Series.str
The string methods are available on Series backed by
a StringArray.
Notes
-----
StringArray returns a BooleanArray for comparison methods.
Examples
--------
>>> pd.array(['This is', 'some text', None, 'data.'], dtype="string")
<StringArray>
['This is', 'some text', <NA>, 'data.']
Length: 4, dtype: string
Unlike ``object`` dtype arrays, ``StringArray`` doesn't allow non-string
values.
>>> pd.array(['1', 1], dtype="string")
Traceback (most recent call last):
...
ValueError: StringArray requires an object-dtype ndarray of strings.
For comparison methods, this returns a :class:`pandas.BooleanArray`
>>> pd.array(["a", None, "c"], dtype="string") == "a"
<BooleanArray>
[True, <NA>, False]
Length: 3, dtype: boolean
"""
# undo the PandasArray hack
_typ = "extension"
def __init__(self, values, copy=False):
values = extract_array(values)
skip_validation = isinstance(values, type(self))
super().__init__(values, copy=copy)
self._dtype = StringDtype()
if not skip_validation:
self._validate()
def _validate(self):
"""Validate that we only store NA or strings."""
if len(self._ndarray) and not lib.is_string_array(self._ndarray, skipna=True):
raise ValueError("StringArray requires a sequence of strings or pandas.NA")
if self._ndarray.dtype != "object":
raise ValueError(
"StringArray requires a sequence of strings or pandas.NA. Got "
f"'{self._ndarray.dtype}' dtype instead."
)
@classmethod
def _from_sequence(cls, scalars, dtype=None, copy=False):
if dtype:
assert dtype == "string"
result = np.asarray(scalars, dtype="object")
if copy and result is scalars:
result = result.copy()
# Standardize all missing-like values to NA
# TODO: it would be nice to do this in _validate / lib.is_string_array
# We are already doing a scan over the values there.
na_values = isna(result)
if na_values.any():
if result is scalars:
# force a copy now, if we haven't already
result = result.copy()
result[na_values] = StringDtype.na_value
return cls(result)
@classmethod
def _from_sequence_of_strings(cls, strings, dtype=None, copy=False):
return cls._from_sequence(strings, dtype=dtype, copy=copy)
def __arrow_array__(self, type=None):
"""
Convert myself into a pyarrow Array.
"""
import pyarrow as pa
if type is None:
type = pa.string()
values = self._ndarray.copy()
values[self.isna()] = None
return pa.array(values, type=type, from_pandas=True)
def _values_for_factorize(self):
arr = self._ndarray.copy()
mask = self.isna()
arr[mask] = -1
return arr, -1
def __setitem__(self, key, value):
value = extract_array(value, extract_numpy=True)
if isinstance(value, type(self)):
# extract_array doesn't extract PandasArray subclasses
value = value._ndarray
key = check_array_indexer(self, key)
scalar_key = lib.is_scalar(key)
scalar_value = lib.is_scalar(value)
if scalar_key and not scalar_value:
raise ValueError("setting an array element with a sequence.")
# validate new items
if scalar_value:
if isna(value):
value = StringDtype.na_value
elif not isinstance(value, str):
raise ValueError(
f"Cannot set non-string value '{value}' into a StringArray."
)
else:
if not is_array_like(value):
value = np.asarray(value, dtype=object)
if len(value) and not lib.is_string_array(value, skipna=True):
raise ValueError("Must provide strings.")
super().__setitem__(key, value)
def fillna(self, value=None, method=None, limit=None):
# TODO: validate dtype
return super().fillna(value, method, limit)
def astype(self, dtype, copy=True):
dtype = pandas_dtype(dtype)
if isinstance(dtype, StringDtype):
if copy:
return self.copy()
return self
elif isinstance(dtype, _IntegerDtype):
arr = self._ndarray.copy()
mask = self.isna()
arr[mask] = 0
values = arr.astype(dtype.numpy_dtype)
return IntegerArray(values, mask, copy=False)
return super().astype(dtype, copy)
def _reduce(self, name, skipna=True, **kwargs):
raise TypeError(f"Cannot perform reduction '{name}' with string dtype")
def value_counts(self, dropna=False):
from pandas import value_counts
return value_counts(self._ndarray, dropna=dropna).astype("Int64")
# Override parent because we have different return types.
@classmethod
def _create_arithmetic_method(cls, op):
# Note: this handles both arithmetic and comparison methods.
def method(self, other):
from pandas.arrays import BooleanArray
assert op.__name__ in ops.ARITHMETIC_BINOPS | ops.COMPARISON_BINOPS
if isinstance(other, (ABCIndexClass, ABCSeries, ABCDataFrame)):
return NotImplemented
elif isinstance(other, cls):
other = other._ndarray
mask = isna(self) | isna(other)
valid = ~mask
if not lib.is_scalar(other):
if len(other) != len(self):
# prevent improper broadcasting when other is 2D
raise ValueError(
f"Lengths of operands do not match: {len(self)} != {len(other)}"
)
other = np.asarray(other)
other = other[valid]
if op.__name__ in ops.ARITHMETIC_BINOPS:
result = np.empty_like(self._ndarray, dtype="object")
result[mask] = StringDtype.na_value
result[valid] = op(self._ndarray[valid], other)
return StringArray(result)
else:
# logical
result = np.zeros(len(self._ndarray), dtype="bool")
result[valid] = op(self._ndarray[valid], other)
return BooleanArray(result, mask)
return compat.set_function_name(method, f"__{op.__name__}__", cls)
@classmethod
def _add_arithmetic_ops(cls):
cls.__add__ = cls._create_arithmetic_method(operator.add)
cls.__radd__ = cls._create_arithmetic_method(ops.radd)
cls.__mul__ = cls._create_arithmetic_method(operator.mul)
cls.__rmul__ = cls._create_arithmetic_method(ops.rmul)
_create_comparison_method = _create_arithmetic_method
StringArray._add_arithmetic_ops()
StringArray._add_comparison_ops()
| BugsInPy/BugsInPy/temp/projects/pandas/bug-37-fixed/pandas/pandas/core/arrays/string_.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-37-buggy/pandas/pandas/core/arrays/string_.py |
pandas-bug-10 | BugsInPy/BugsInPy/temp/projects/pandas/bug-10-fixed/pandas/pandas/core/internals/blocks.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-10-buggy/pandas/pandas/core/internals/blocks.py |
|
pandas-bug-23 | BugsInPy/BugsInPy/temp/projects/pandas/bug-23-fixed/pandas/pandas/core/indexes/datetimelike.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-23-buggy/pandas/pandas/core/indexes/datetimelike.py |
|
pandas-bug-151 | BugsInPy/BugsInPy/temp/projects/pandas/bug-151-fixed/pandas/pandas/core/arrays/numpy_.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-151-buggy/pandas/pandas/core/arrays/numpy_.py |
|
pandas-bug-112 | BugsInPy/BugsInPy/temp/projects/pandas/bug-112-fixed/pandas/pandas/core/indexes/interval.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-112-buggy/pandas/pandas/core/indexes/interval.py |
|
pandas-bug-1 | BugsInPy/BugsInPy/temp/projects/pandas/bug-1-fixed/pandas/pandas/core/dtypes/common.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-1-buggy/pandas/pandas/core/dtypes/common.py |
|
pandas-bug-54 | BugsInPy/BugsInPy/temp/projects/pandas/bug-54-fixed/pandas/pandas/core/dtypes/dtypes.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-54-buggy/pandas/pandas/core/dtypes/dtypes.py |
|
pandas-bug-7 | BugsInPy/BugsInPy/temp/projects/pandas/bug-7-fixed/pandas/pandas/core/indexes/base.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-7-buggy/pandas/pandas/core/indexes/base.py |
|
pandas-bug-91 | BugsInPy/BugsInPy/temp/projects/pandas/bug-91-fixed/pandas/pandas/core/indexes/timedeltas.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-91-buggy/pandas/pandas/core/indexes/timedeltas.py |
|
pandas-bug-61 | BugsInPy/BugsInPy/temp/projects/pandas/bug-61-fixed/pandas/pandas/core/series.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-61-buggy/pandas/pandas/core/series.py |
|
pandas-bug-155 | BugsInPy/BugsInPy/temp/projects/pandas/bug-155-fixed/pandas/pandas/core/window/rolling.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-155-buggy/pandas/pandas/core/window/rolling.py |
|
pandas-bug-73 | BugsInPy/BugsInPy/temp/projects/pandas/bug-73-fixed/pandas/pandas/core/frame.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-73-buggy/pandas/pandas/core/frame.py |
|
pandas-bug-114 | BugsInPy/BugsInPy/temp/projects/pandas/bug-114-fixed/pandas/pandas/core/indexes/base.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-114-buggy/pandas/pandas/core/indexes/base.py |
|
pandas-bug-43 | BugsInPy/BugsInPy/temp/projects/pandas/bug-43-fixed/pandas/pandas/core/ops/__init__.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-43-buggy/pandas/pandas/core/ops/__init__.py |
|
pandas-bug-18 | BugsInPy/BugsInPy/temp/projects/pandas/bug-18-fixed/pandas/pandas/core/window/common.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-18-buggy/pandas/pandas/core/window/common.py |
|
pandas-bug-13 | BugsInPy/BugsInPy/temp/projects/pandas/bug-13-fixed/pandas/pandas/core/dtypes/missing.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-13-buggy/pandas/pandas/core/dtypes/missing.py |
|
pandas-bug-130 | BugsInPy/BugsInPy/temp/projects/pandas/bug-130-fixed/pandas/pandas/core/groupby/ops.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-130-buggy/pandas/pandas/core/groupby/ops.py |
|
pandas-bug-131 | BugsInPy/BugsInPy/temp/projects/pandas/bug-131-fixed/pandas/pandas/core/indexes/accessors.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-131-buggy/pandas/pandas/core/indexes/accessors.py |
|
pandas-bug-89 | BugsInPy/BugsInPy/temp/projects/pandas/bug-89-fixed/pandas/pandas/core/reshape/reshape.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-89-buggy/pandas/pandas/core/reshape/reshape.py |
|
pandas-bug-166 | BugsInPy/BugsInPy/temp/projects/pandas/bug-166-fixed/pandas/pandas/core/frame.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-166-buggy/pandas/pandas/core/frame.py |
|
pandas-bug-62 | BugsInPy/BugsInPy/temp/projects/pandas/bug-62-fixed/pandas/pandas/core/internals/blocks.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-62-buggy/pandas/pandas/core/internals/blocks.py |
|
pandas-bug-92 | BugsInPy/BugsInPy/temp/projects/pandas/bug-92-fixed/pandas/pandas/core/generic.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-92-buggy/pandas/pandas/core/generic.py |
|
pandas-bug-88 | BugsInPy/BugsInPy/temp/projects/pandas/bug-88-fixed/pandas/pandas/core/reshape/pivot.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-88-buggy/pandas/pandas/core/reshape/pivot.py |
|
pandas-bug-48 | BugsInPy/BugsInPy/temp/projects/pandas/bug-48-fixed/pandas/pandas/core/groupby/generic.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-48-buggy/pandas/pandas/core/groupby/generic.py |
|
pandas-bug-20 | BugsInPy/BugsInPy/temp/projects/pandas/bug-20-fixed/pandas/pandas/tseries/offsets.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-20-buggy/pandas/pandas/tseries/offsets.py |
|
pandas-bug-132 | BugsInPy/BugsInPy/temp/projects/pandas/bug-132-fixed/pandas/pandas/core/nanops.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-132-buggy/pandas/pandas/core/nanops.py |
|
pandas-bug-101 | BugsInPy/BugsInPy/temp/projects/pandas/bug-101-fixed/pandas/pandas/core/dtypes/cast.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-101-buggy/pandas/pandas/core/dtypes/cast.py |
|
pandas-bug-143 | BugsInPy/BugsInPy/temp/projects/pandas/bug-143-fixed/pandas/pandas/core/indexes/range.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-143-buggy/pandas/pandas/core/indexes/range.py |
|
pandas-bug-168 | BugsInPy/BugsInPy/temp/projects/pandas/bug-168-fixed/pandas/pandas/core/groupby/grouper.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-168-buggy/pandas/pandas/core/groupby/grouper.py |
|
pandas-bug-93 | BugsInPy/BugsInPy/temp/projects/pandas/bug-93-fixed/pandas/pandas/core/arrays/datetimelike.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-93-buggy/pandas/pandas/core/arrays/datetimelike.py |
|
pandas-bug-2 | BugsInPy/BugsInPy/temp/projects/pandas/bug-2-fixed/pandas/pandas/core/indexing.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-2-buggy/pandas/pandas/core/indexing.py |
|
pandas-bug-156 | BugsInPy/BugsInPy/temp/projects/pandas/bug-156-fixed/pandas/pandas/core/sparse/frame.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-156-buggy/pandas/pandas/core/sparse/frame.py |
|
pandas-bug-25 | BugsInPy/BugsInPy/temp/projects/pandas/bug-25-fixed/pandas/pandas/core/arrays/datetimes.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-25-buggy/pandas/pandas/core/arrays/datetimes.py |
|
pandas-bug-49 | BugsInPy/BugsInPy/temp/projects/pandas/bug-49-fixed/pandas/pandas/core/strings.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-49-buggy/pandas/pandas/core/strings.py |
|
pandas-bug-68 | BugsInPy/BugsInPy/temp/projects/pandas/bug-68-fixed/pandas/pandas/core/arrays/interval.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-68-buggy/pandas/pandas/core/arrays/interval.py |
|
pandas-bug-107 | BugsInPy/BugsInPy/temp/projects/pandas/bug-107-fixed/pandas/pandas/core/frame.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-107-buggy/pandas/pandas/core/frame.py |
|
pandas-bug-4 | BugsInPy/BugsInPy/temp/projects/pandas/bug-4-fixed/pandas/pandas/core/indexes/base.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-4-buggy/pandas/pandas/core/indexes/base.py |
|
pandas-bug-87 | BugsInPy/BugsInPy/temp/projects/pandas/bug-87-fixed/pandas/pandas/core/reshape/pivot.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-87-buggy/pandas/pandas/core/reshape/pivot.py |
|
pandas-bug-59 | BugsInPy/BugsInPy/temp/projects/pandas/bug-59-fixed/pandas/pandas/core/window/rolling.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-59-buggy/pandas/pandas/core/window/rolling.py |
|
pandas-bug-38 | BugsInPy/BugsInPy/temp/projects/pandas/bug-38-fixed/pandas/pandas/core/reshape/reshape.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-38-buggy/pandas/pandas/core/reshape/reshape.py |
|
pandas-bug-52 | BugsInPy/BugsInPy/temp/projects/pandas/bug-52-fixed/pandas/pandas/core/groupby/generic.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-52-buggy/pandas/pandas/core/groupby/generic.py |
|
pandas-bug-127 | BugsInPy/BugsInPy/temp/projects/pandas/bug-127-fixed/pandas/pandas/core/generic.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-127-buggy/pandas/pandas/core/generic.py |
|
pandas-bug-164 | BugsInPy/BugsInPy/temp/projects/pandas/bug-164-fixed/pandas/pandas/core/tools/datetimes.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-164-buggy/pandas/pandas/core/tools/datetimes.py |
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pandas-bug-167 | BugsInPy/BugsInPy/temp/projects/pandas/bug-167-fixed/pandas/pandas/core/indexes/base.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-167-buggy/pandas/pandas/core/indexes/base.py |
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pandas-bug-72 | BugsInPy/BugsInPy/temp/projects/pandas/bug-72-fixed/pandas/pandas/core/internals/blocks.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-72-buggy/pandas/pandas/core/internals/blocks.py |
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pandas-bug-138 | BugsInPy/BugsInPy/temp/projects/pandas/bug-138-fixed/pandas/pandas/core/reshape/tile.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-138-buggy/pandas/pandas/core/reshape/tile.py |
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pandas-bug-90 | BugsInPy/BugsInPy/temp/projects/pandas/bug-90-fixed/pandas/pandas/_testing.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-90-buggy/pandas/pandas/_testing.py |
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pandas-bug-153 | BugsInPy/BugsInPy/temp/projects/pandas/bug-153-fixed/pandas/pandas/core/internals/blocks.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-153-buggy/pandas/pandas/core/internals/blocks.py |
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pandas-bug-65 | BugsInPy/BugsInPy/temp/projects/pandas/bug-65-fixed/pandas/pandas/io/common.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-65-buggy/pandas/pandas/io/common.py |
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pandas-bug-36 | BugsInPy/BugsInPy/temp/projects/pandas/bug-36-fixed/pandas/pandas/core/dtypes/missing.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-36-buggy/pandas/pandas/core/dtypes/missing.py |
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pandas-bug-159 | BugsInPy/BugsInPy/temp/projects/pandas/bug-159-fixed/pandas/pandas/core/frame.py,BugsInPy/BugsInPy/temp/projects/pandas/bug-159-buggy/pandas/pandas/core/frame.py |